Title: NA61/SHINE facility at the CERN SPS: beams and detector system
Author: N. Abgrall, O. Andreeva, A. Aduszkiewicz, Y. Ali, T. Anticic, N. Antoniou,
Andrzej Grzeszczuk, Emil Kaptur, Jan Kisiel, Seweryn Kowalski, Szymon Puławski, Katarzyna Schmidt, Andrzej Wilczek, Wiktor Zipper i in.
Citation style: Abgrall N.,. Andreeva O, Aduszkiewicz A., Ali Y., Anticic T., Antoniou N., Grzeszczuk Andrzej, Kaptur Emil, Kisiel Jan, Kowalski Seweryn, Puławski Szymon, Schmidt Katarzyna, Wilczek Andrzej, Zipper Wiktor i in. (2014). NA61/SHINE facility at the CERN SPS: beams and detector system. "Journal of Instrumentation" (Vol. 9, iss. 6
(2014), art. no. P06005), doi 10.1088/1748-0221/9/06/P06005
Journal of Instrumentation
OPEN ACCESS Related content
- New pixelized Micromegas detector for the NA61/SHINE facility at the CERN SPS: beams COMPASS experiment D Neyret, M Anfreville, Y Bedfer et al. and detector system - The triple GEM detector as beam monitor for relativistic hadron beams E Aza, M Magistris, F Murtas et al. To cite this article: N Abgrall et al 2014 JINST 9 P06005 - The NA61/SHINE long target pilot analysis for T2K Nicolas Abgrall and the NA61/SHINE collaboration View the article online for updates and enhancements. Recent citations
- Hadron yields and fluctuations at energies available at the CERN Super Proton Synchrotron: System-size dependence from Pb + Pb to p+p collisions A. Motornenko et al
- Study of pion kaon and proton in proton–carbon interactions at 158 GeV/c using hadron production models Y. Ali et al
- Influence of target material impurities on physical results in relativistic heavy-ion collisions D. Bana et al
This content was downloaded from IP address 155.158.37.226 on 25/03/2019 at 10:41 2014 JINST 9 P06005 m a u h t d k b i s c , l u g f s p EDIALAB , o r June 5, 2014 u M p n : April 14, 2014 , b g : A. Bravar, January 23, 2014 T. Paul, J. Kisiel, k : a ISSA f Z. Majka, c S r K. Sakashita, B. Rossi, D. Jokovic, V.P. Kondratiev, M. Shibata, A. Marchionni, UBLISHED b V. Matveev, W. Dominik, G. Stefanek, CCEPTED x j b A. Redij, h P l c T. Czopowicz, h A d N. Antoniou, a ECEIVED l e R M. Ga´zdzicki, A. Kurepin, T. Nakadaira, B.A. Popov, q g a k A. Haesler, M. Bogusz, j b I. Efthymiopoulos, D. Kolev, M. Kirejczyk, i D. Manic, UBLISHINGFOR c E. Rondio, g doi:10.1088/1748-0221/9/06/P06005 o P. Staszel, z A. Ivashkin, A. Sadovsky, S. Di Luise, T. Anticic, d A.D. Panagiotou, M. Ravonel, s A. Fulop, m f J. Pluta, M. Cirkovic, d q y T. Matulewicz, D. Sgalaberna, IOPP q f 2 , i S. Murphy, s F. Guber, d s t ´ R. Engel, ckowiak-Pawłowska, ´ ¨ nski, ohrich, k Y. Ali, A. Krasnoperov, c Z. Sosin, M. Bogomilov, ´ nski, t G. Palla, D. R i k S. Igolkin, M. Ma Z. Fodor, x n W. Rauch, D. Manglunki, v g V.I. Kolesnikov, m l D. Kielczewska, l F. Diakonos, UBLISHEDBY u t P. Seyboth, i R. Płaneta, P ´ owczy M. Rybczy u H.-J. Mathes, p r q K. Dynowski, A. Grzeszczuk, P. Christakoglou, J. Blumer, n k g A. Robert, St. Mr S. Kowalski, a R. Idczak, p v d p D. Maletic, J. Puzovic, E. Kaptur, t g T. Palczewski, M. Słodkowski, f A. Aduszkiewicz, G.A. Feofilov, C. Pistillo, u c b T. Kobayashi, o b K. Marton, H. Dembinski, T. Sekiguchi, V.V. Lyubushkin, w b a t q A. Rustamov, h A. Blondel, h M. Messina, J. Dumarchez, S.A. Bunyatov, g m S. Puławski, M. Hierholzer, K. Grebieszkow, d A. Fabich, P. Koversarski, V. Marin, E. Richter-Wa¸s, c u b A.I. Malakhov, p a d O. Andreeva, r A. Laszlo, K. Nishikawa, k O. Petukhov, F. Bay, A. Kapoyannis, a E. Skrzypczak, S. Debieux, K. Schmidt, p d 1 g e , A. Rubbia, CERN 2014 for the benefit of the NA61/SHINE collaboration, published under the f q l k S. Kleinfelder, i c terms of the Creative Commons Attribution 3.0 License by IOP Publishing Ltd and Sissa q Deceased. Corresponding author. 1 2 R. Renfordt, G.L. Melkumov, M. Nirkko, W. Peryt, M. Posiadala, M. Roth, Medialab srl. Anypublished further article’s distribution title, journal of citation this and work DOI. must maintain attribution to the author(s) and the J. Brzychczyk, T. Drozhzhova, A. Ereditato, B. Maksiak, A. Marcinek, M. Savic, R. Sipos, B. Baatar, N. Davis, T. Kiss, A. Korzenev, D. Larsen, The NA61/SHINE collaboration N. Abgrall, NA61/SHINE facility at the CERN SPS:detector beams system and K. Kadija, M. Golubeva, T. Hasegawa, 2014 JINST 9 P06005 s i g D. Veberic, f t Z. Włodarczyk, t V. Tereshchenko, u M. Vassiliou, i A. Wilczek, and W. Zipper m n M. Tada, i M. Unger, i L. Zambelli M. Szuba, d e L. Vinogradov, q ¨ at, R. Ulrich, ´ nski, v T. Susa, r O. Wyszy L. Turko, s j G. Vesztergombi, m H. Stroebele, x R. Tsenov, q ¨ ¨ ur Teilchenphysik (IPP), ETHZ Hoenggerberg, Swiss Federal Institute of Technology, ur Kernphysik, Goethe-Universit ˇ cka 54, HR-10000 Zagreb, Croatia ˙ za 69, PL-00-681 Warsaw, Poland Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow, Poland Rudjer Boskovic Institute, Bijeni Nuclear and Particle Physics Division, UniversityPanepistimiopolis, of Ilisia Athens, GR 157 71 Athens, Greece Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow region, Russia Institut f Schafmattstr. 20, CH-8093 Zurich, Switzerland Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Karlsruhe, Germany Department of Atomic Physics, Faculty of5 Physics, J. Sofia Bourchier University Blvd, “St. 1164 Kliment Sofia, Ohridski”, Bulgaria Faculty of Physics, Warsaw University of Technology, Koszykowa 75, PL-00-662 Warsaw, Poland Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia St. Petersburg State University, Ulyanovskaya str. 1, 198504 St. Petersburg, Russia LPNHE, Universites Paris VI and VII, Case 200, 4 Place Jussieu, 75005 Paris,European France Organization for Nuclear Research (CERN), CH-1211 Geneva 23, Switzerland Albert Einstein Center for Fundamental Physics,Sidlerstrasse Laboratory 5, for High CH-3012 Energy Bern, Physics, Switzerland University ofDepartment Bern, of High Energy Physics, Wigner Research Centre for Physics ofKonkoly-Thege the M. Hungarian u. Academy 29-33, of 1121 Sciences, Budapest, Hungary Institut f Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland Departement de Physique Nucleaire et Corpusculaire,24 University quai of Ernest-Ansermet, Geneva, CH-1211 Geneva 4,Institute Switzerland for Nuclear Research, 60-th October Anniversary prospect 7A, 117 312Faculty of Moscow, Russia Physics, University of Warsaw, Ho Max-von-Laue-Straße 1, D-60438 Frankfurt am Main, Germany Institute of Physics, Jan Kochanowski University, Swietokrzyska 15, 25-406 Kielce, Poland i j l t s r f e c k g h n o p q a b d m J. Stepaniak, T. Tolyhi, V.V. Vechernin, A. Wojtaszek-Szwarz, 2014 JINST 9 P06005 Be beams) in 2011. 7 : 1401.4699 : Particle identification methods; Time projection chambers; Instrumentation for ra- : NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a multi-purpose experi- RINT rplaneta@mail.cern.ch P IVE NA61/SHINE has greatly profited from the long development of the CERN proton and ion This paper describes the state of the NA61/SHINE facility — the beams and the detector X BSTRACT EYWORDS R National Centre for Nuclear Research, Andrzeja Sołtana 7, 05-400 Otwock, Poland Fachhochschule Frankfurt am Main, Nibelungenplatz 1, D-60318 Frankfurt am Main, Germany Department of Physics and Technology, University ofAllegt. 55, Bergen, 5007 Bergen, Norway E-mail: Department of Electrical Engineering and Computer4416 Science, Engineering University Hall, of Irvine, California, CA, 92697-2625, U.S.A. Institute of Particle and Nuclear Studies,1-1 High Oho, Energy Tsukuba, Accelerator 305-0801, Research Organization Japan (KEK), Department of Physics and Astronomy, Universitypl. of M. Wrocław, Borna 9, 50-204 Wrocław, Poland z y v x u w A K A mental facility to study hadroncollisions production at in the hadron-proton, CERN hadron-nucleus and Superbeams nucleus-nucleus Proton in 2009 Synchrotron. and It with ion recorded beams the (secondary first physics data with hadron sources and the accelerator chain ashas well recently as been the H2 modified beamlinebeams to of for the NA61/SHINE. also CERN Numerous serve North components Area. asits of The the predecessors, a latter NA61/SHINE in fragment set-up particular, were separatorupgrades the inherited as of from last the needed one, legacy equipment to the were produce NA49 introduced by the experiment. the Be NA61/SHINE Important Collaboration. newsystem — detectors before and the CERN Long Shutdown I, which started in March 2013. dioactive beams (fragmentation devices; fragmentarators; and isotope, ion separators and incl. atom ISOL;tectors traps; isobar weak-beam sep- diagnostics; radioactive-beam ion sources); Trigger de- 2014 JINST 9 P06005 3 – 1 – 2.1 Proton acceleration2.2 chain3 Ion accelerator2.35 chain H2 beamline6 2.4 Hadron beams7 2.5 Primary and secondary ion beams9 3.1 Beam counters 3.2 A-detector 3.3 Beam Position3.4 Detectors Z-detectors 3.5 Trigger system 4.1 VTPC, MTPC4.2 and GAP-TPC He beam4.3 pipes Magnets 4.4 Gas system4.5 and monitoring TPC Front4.6 End Electronics Physics performance 5.1 ToF-L, ToF-R 5.2 ToF-F 6.1 Calorimeter design 6.2 PSD photodetectors 6.3 Performance of the PSD calorimeter 14 7.113 Targets 7.2 Low Momentum Particle14 Detector 18 8.115 16 Readout electronics8.2 and DAQ Detector Control System 22 24 19 25 22 34 26 32 32 29 37 40 43 36 Contents 12 Introduction 2 Beams 3 Beam detectors and trigger system 4 TPC tracking system 5 Time of Flight systems 612 Projectile Spectator Detector 7 Targets and LMPD 8 Data acquisition and detector control systems 17 9 Summary and outlook 26 31 40 36 44 2014 JINST 9 P06005 Be beams) in 2011. The first 7 – 2 – strongly interacting matter which is pursuedcollisions by and investigating p+p, p+Pb and nucleus-nucleus beam flux in thereliable long-baseline simulations neutrino of cosmic-ray oscillation air experiments showers [5,6]. [3,4] as well as for more NA61/SHINE has greatly profited from the long development of the CERN proton and ion The layout of the NA61/SHINE detector is sketched in figure1. It consists of a large accep- This paper describes the NA61/SHINE facility, the beams and the detector system. Special The experiment was proposed to CERN in November 2006 [1]. Based on this proposal pi- (i) study the properties of the onset of deconfinement [2] and search for the critical point of (ii) precise hadron production measurements for improving calculations of the initial neutrino sources, the accelerator chain,has as well recently as been the modifiedbeams H2 to for beamline NA61/SHINE. also of Numerous serve the components CERN asits of predecessors, North the a in NA61/SHINE Area. particular, fragment set-up the were separator last The inherited one, as latter from the needed NA49 experiment. to producetance hadron the spectrometer with Be excellent capabilities inand charged particle identification momentum by measurements a setThe of high six resolution Time forward Projection calorimeter,around the Chambers the Projectile as beam Spectator direction, well Detector, which as measures inber Time-of-Flight nucleus-nucleus energy of detectors. reactions flow spectator is (non-interacted) primarily a nucleonshadron-nucleus measure interactions, and of the thus collision the centrality related num- is to determinedticles emitted by the from counting centrality the low nuclear momentum of target par- the withAn the collision. array LMPD of detector beam (a For detectors small identifies TPC) beam surroundingions, particles, the and secondary target. hadrons measures and precisely ions their as trajectories. well as primary attention is paid to theThe presentation of components the inherited components from which thebriefly were past here. constructed experiments for The and paper NA61/SHINE. described is organized elsewhereare as are introduced follows. presented and In only section2 thetheemployed North proton hadron and Area and ion H2 ion acceleration beamline beams chains as are is given. the described. trigger The system NA61/SHINE Moreover beam arewhich basic and presented consists properties trigger in of detectors of section3. the as the TPC Section4 well detectorsgasis and with devoted two front to super-conducting end magnets. the electronics, The TPC twoProjectile Time tracking of beam Spectator Flight system Detector pipes system in filled is section6. with described In in helium 7 section section5 andthe the targets and the Low Momentum Particle experimental results were published in [8,9]. lot data taking took placeCERN in and September the collaborating 2007. institutionshadron The was beams signed Memorandum were in recorded of in October Understanding 2009 2008. [7] and with between The ion first beams (secondary physics data with 1 Introduction NA61/SHINE (SPS Heavy Ion andhadron Neutrino production Experiment) in [1] hadron-proton, is hadron-nucleusSuper a and Proton multi-purpose nucleus-nucleus Synchrotron facility collisions (SPS). to at The the study NA61/SHINE physics CERN goals include: 2014 JINST 9 P06005 PSD (horizontal) z - x ToF-L ToF-R S5 ToF-F MTPC-L MTPC-R ~13 m VTPC-2 – 3 – V1 BPD-3 p Vertex magnets Vertex V1 TPC GAP S4 V0 S2 VTPC-1 s pulse length [12]. The 50 MeV proton beam from LINAC2 is then µ THC BPD-1 BPD-2 S1 Target CEDAR z . Schematic layout of the NA61/SHINE experiment at the CERN SPS (horizontal cut in the beam The CERN accelerator chain, with its components relevant for NA61/SHINE beams exposed, mm mrad, during a 120 x y Beam π plane, not to scale). The2009 beam is and presented. trigger counter The configurationdirection chosen used is for right-handed along data coordinate taking the system on z is p+p axis. shown interactions on in The the magnetic plot. field bends The charged incoming particle beam trajectories in the Figure 1 is shown in figure2.accelerators, before From they reach the the SPS source, forArea the final and acceleration beams and the subsequent of NA61/SHINE extraction to ions experiment. theinjector and North chain The to protons protons the pass and PS, through required ions to follow a match a series the different beam of path parameters2.1 for in their the acceleration. pre- Proton acceleration chain The proton beam is generated fromvide hydrogen a gas beam by current a of duo-plasmatronand up ion bunches to source, the 300 which mA beam, can [10]. and pro- varez The accelerates drift Radio-Frequency it tube Quadrupole to linear RFQ2 750 [11] keV accelerator.of focuses for the The injection three beam into tanks LINAC2, atrate have a the of a three-tank exit 0.8 total Al- Hz, of length LINAC2 the of delivers15 a 33.3 tanks m, current is and of respectively the up 10.3, energy to 170 30.5, mA within and a 50 MeV. 90% transverse emittance With of a repetition plane. The drift direction in the TPCs is along the y (vertical) axis. Detector are presented.section8. Finally, Section9 datacloses the acquisition paper and with summary detector and control outlook. systems are described2 in Beams This section starts from the presentationtinues of with the a CERN brief proton and descriptionexperiment. ion of accelerator the chains, H2 and con- beamline and secondary hadron and ion beams for the 2014 JINST 9 P06005 for c beam / c /
) I (
o s m s k
a 0 S
3 n 7 a r G s no i r a ut
e
ne r CNGS A
* t s a 8 1 E T S P – 4 – LEIR
SS , the beam passes from an intermediate flat-top where the
3 c
C E D L O S I
A s N I L / n B PP o i
NA61/SHINE
PS
b
SS 2 LHC
C P *
r A
N
a I L
a b
e p
r p stripper
A AD
h
t * r
o N , on fixed harmonic 4620 (200 MHz). At the top momentum, the beam c F /
2 O
1 * T T - n protons per ring. After acceleration to 1.4 GeV, the beam from the four rings is extracted . Schematic layout of the CERN accelerator complex relevant for the NA61/SHINE ion and proton 13 is accelerated to 400 GeV is de-bunched and slowly extracted overduration several for seconds the using North a Area third-integer resonance. experimentsand depends its The on users, spill the and can overall be optimisation between for 4.5 the s SPS and machine 10 s with a duty cycle of about 30%. RF system splits the eight bunchestop into momentum, two the and beam changes is thethe operation de-bunched to and RF harmonic re-captured structure sixteen. at of At harmonic the the from 420 receiving in the machine, PS order over the to five 6.8 easily turns km using match turn circumference a extraction staircase-shaped SPS. is kicker pulse. unique The to This beam “continuoustakes the is transfer” two PS. extracted multi- PS As cycles the to SPS fillare is the used 11 SPS for with times the the rising larger and five-turn than extraction. falling the edge The PS of remaining in the two circumference, SPS half-turn it injection gaps kicker. In the SPS, the 14 GeV Figure 2 beam operation. (Top view, not to scale). distributed in the four ringstransfer line. of the The multi-turn PS injection boosterover system 10 (PSB) of using the PSB a allowsand staircase-like to recombined kicker accumulate in magnet for the in up extraction to the accelerator line, 13 [13]. to turns, The be PS sent hasinjection a to into circumference the of the Proton 628 Super Synchrotron m and Proton (PS),experiments, accelerates the CERN’s Synchrotron the PSB oldest (SPS). beam beams after to In recombination 14which GeV consists a are of typical injected a into proton train the cycle of eight eighteight. for consecutive bunches During buckets the (two the of acceleration fixed-target per the to ring), RF 14 GeV of the PS that operates at harmonic 2014 JINST 9 P06005 ◦ 21, in order to , 24 , 12 s pulse. The LINAC3 , µ century [16] in order to 14 , st 16 = h cavities, and fast-extracted towards the PS. At TM ions. – 5 – 9 ions each, are injected into the SPS, with a bunch-to- 8 169, using one of the PS’s three 80 MHz cavities. At the Pb is inserted in a filament-heated crucible at the rear of 10 = m thick carbon foil provides the first stripping stage at the × 208 h µ 1%, according to the time along the 200 3 ± . , and the time dependence of the momentum distribution coupled with the large ◦ A of Pb54+ from LINAC3 is injected over about 70 turns into the Low Energy Ion Ring µ In the PS, the two ion bunches from LEIR are injected into two adjacent buckets of harmonic A sample of isotopically pure The two bunches, now about 3 currently operates at 5 Hz. A 0 this point the total beam intensity is about 10 value (10 m) of the dispersion functionto in six the times, injection region. every The 200transverse ms. injection and process longitudinal The is emittances. repeated whole up At process theharmonic is end 2, performed of accelerated the under to seven 72 electron MeV/u injections, cooling by the reducing Finemet beam is the bunched on 16 and accelerated by theexpansion. 3–10 MHz This process system consists to of 5.9 a GeV/u, series with of an harmonic intermediate changes: flat-top for batch the ECR source, whilst oxygenlong is pulse injected of as 14.5 support GHzturn gas. microwaves ionizes accelerates the With electrons a leadafterglow 10 to vapor Hz mode, at form repetition i.e. the an rate, the surface a oxygen microwavestate 50 of pulse ions plasma, ms from the is which the switched crucible. source in off, increasessource dramatically. when The with The the source an ions intensity operates are energy of electrostatically in of extracted the the 2.5 from high keV/u. so-called the charge Out of the different ion species and charge states, a 135 exit of LINAC3, followed byabout a 22 spectrometer which selects(LEIR), the whose Pb54+ unique charge injection state. systemregular fills A the multi-turn current 6-dimensional injection of phase with space. aseptum This decreasing tilted is at horizontal 45 achieved bump, by supplemented a by an electrostatic 2.2 Ion accelerator chain The CERN ion production complex wastarget first programme designed [14, in15]. the It 1990scope was for with rejuvenated the the at LHC’s needs the stringent of beginning demands the of forin high SPS the the brightness 21 fixed ECR ion source. beams Here]. [17 the The case ions of are the generated Pb beam production is considered as an example. spectrometer situated at the exit of(Pb29+) the to enter source the selects LINAC3 those accelerator. leadlong The ions beam RFQ which is which first were operates accelerated ionized to 29 atadapts 250 times keV/u 101.28 the MHz. by the longitudinal 2.66 The bunch m RFQcavity parameters interdigital is to H followed (IH) the by structure, a rest30 that MV four-gap of brings of RF the the accelerating cavity voltage, beam linear which forat energy accelerator a up the which total to same acceleration 4.2 is frequency MeV/u length a as202.56 requiring of MHz. about three- the 8.13 m. RFQ Finally, The (101.28 a MHz), firstbeam 250 while kV momentum cavity over operates the “ramping a range second cavity”, of and also third operating cavities at operate 101.28 MHz, at distributes the bucket transfer into the 200seconds; MHz the system. repetition rate This is process limited can by be the repeated duration of up the to LEIR 12 cycle, times while every the 3.6 total number of finally reach a bunch spacing ofbunches 200 are ns at finally the rebucketed top into energy. Before the fast extraction to the SPS, the exit of the PS, thethick beam aluminium traverses foil. a final stripping stage to produce Pb82+ ions, through a 1 mm 2014 JINST 9 P06005 13 . Alternatively c meters is set by · / the charge of the Z in Tesla , and c ρ / B , where Z / b p 33 . 3 ≈ – 6 – ρ B up to the top SPS energy of 400 GeV c / 9 GeV from which only a fraction of about 40% interacts in the targets, ∼ c / is the momentum of the beam particles in GeV b p The North Area target cavern (TCC2) where the T2 target is located, is about 11 m under- The momentum selection in the beam is done in the vertical plane, as shown in figure3, where ground in order to containbeam the from radiation the SPS. produced In from the the proton impact mode the of extracted the intensity high-intensity from the extracted SPS is typically a few 10 the beamline basically consists of two largerigidity, spectrometers i.e. able to the select momentum particles according to to charge their ratio injections is currently limited by theof SPS the controls ions hardware. during acceleration At wouldthe a yield range fixed a harmonic, of too the the large heavy travelling frequencya mass wave swing fixed cavities (198.51–200.39 MHz) of harmonic, for the the SPSinteger ions (199.5–200.4 harmonic MHz). are number accelerated Hence, is using used, insteadbeam the by of passage turning using “fixed the and frequency” RF switching method, ON itits in at OFF next the which during beam cavity a its centre passage non- absence, frequency throughof to during the the correct the cavities. the frequency. RF The Aside phaseto phase from and be is be its constrained adjusted ready in complexity, by for one aSPS, an relatively drawback the appropriate short of ion modulation portion the beam, (40%) method ofthen after is the acceleration slowly that circumference to extracted of the to the the beam required theacceleration machine. has range energy, North is in In Area left SPS the using varies torange the between de-bunch due third the to naturally integer stability 13 and GeV/u, reasons, resonance is and whichthe like 160 magnets. is GeV/u for due The the protons. to spill lowest duration the possible is limits The overall operational preferred in structure to the depends be power on long supplies the at and number about energy of 10 in users s, although at as the2.3 for SPS. the protons the H2 beamline The extracted beam from the SPSand is transported then over split about into 1 km threecles by parts bending are and each created. focusing one magnets The directedtransport H2 towards momentum a secondary selected primary beamline secondary target emerges particles whereNA61/SHINE from to experiment secondary the the is parti- Experimental T2 located in Hall primary the North targetget middle 1 and being part (EHN1). at of is 535 EHN1, The able m the distance to NA61/SHINEa from production the tar- wide T2 range target. of The momenta H2the from beamline beam can transport can charged transport particles in radiation a safety primary conditions for beam the of experimental protons hall. or ions, of low intensity to comply with the protons per cycle at 400and GeV the rest is dumped inural a shielding controlled for way radiation in and the thethe TCC2 height muon difference cavern. background to The to the surrounding the experimental earth experiments. hallof acts is The as different sufficient T2 nat- to lengths. target reduce station hosts Fromrequested several these beryllium secondary (Be) the particle plates momentum target and plate type.using is a Beams chosen target for which length NA61/SHINE of best arestream 100 usually optimizes dipole or produced the magnets 180 mm. that yield can of A modifyand further the the thus optimisation incident the can angle production of be angle the achieved of primary using the proton a secondary beam set particles on of emitted the up- into target the H2 beamline. the beam optics, particle (in proton charge units). For the energies discussed here the particle momentum can be 2014 JINST 9 P06005 . , ) p Z / A ( the par- b γ m 31 . 3 ≈ 45 mm. ρ ± B Xe ion beams in the times the atomic mass 131 A Ar and 40 7%. Besides the magnetic spectrom- . 1 ± is the beam Lorentz factor and b γ Be ions were produced via fragmentation of the 7 – 7 – , where m b γ = b p . For the start of the ion physics program of the experiment sec- c / GeV were used, as well as attenuated primary Pb82+ ion beams in the range A ) to the NA61/SHINE experiment, produced at the T2 target from the im- c − / π , to 158 − 931 GeV). So finally the rigidity relation for the beamline is K . c 0 / , p = to 350 GeV GeV Be ion beams in the same momentum range were used, as primary ions other than Pb82+ c and ¯ . Schematic view of the vertical plane of the H2 beamline in the configuration used for the ion A 7 / + π For the NA61/SHINE experiment secondary hadron beams in the momentum range from , + Figure 3 fragment separation. The dimensions aredifference not between to T2 scale, and e.g. the the EHN1 beamline is is about more 12 than m, 600 the m aperture long, of the thewritten height quadrupoles in is the relativistic limit as Pb82+ ions in the T2 target. Starting in 2015 attenuated primary were not available before 2015. The secondary ticle mass, which can beunit expressed (1amu in terms of the atomic mass number ondary from 13 13 GeV Each spectrometer consists of six dipoleand magnets collimators that defining deflect the the central beamof trajectory. by about a The total 0.13% beam angle and spectrometer of a haseters, 41 mrad maximum an the rigidity intrinsic beamline resolution acceptance is of position, equipped profile with and dedicated intensity devices atCherenkov which various or locations, provide pulse as information height well and onlike as spectrum heavy the particle ions. analysis beam identification detectors detectors to like identify multiply charged particles same momentum range will be delivered toof NA61/SHINE. the The hadron next and section ion presents further beams details employed by the experiment2.4 before Long Shutdown I. Hadron beams The H2 beamline can transport and deliver positively or negatively charged secondary hadrons ( K 2014 JINST 9 P06005 , ) c / )) per middle − K ( + ), 31 ( K left ), or − π ( + π are presented in figure4. The ) or p c ( ¯ / p and 158 GeV and Nitrogen for lower momenta. The counter c c / / – 8 – , 31 GeV c / filled Cherenkov detectors, similar in construction to those used at present but operating up 2 ). right ( c / . . Counts of hadrons per incident beam particle from the CEDAR counter as a function of the gas c / detector in anti-coincidence. The pressure range at which counts of a wanted hadron ( Ref. [19] discusses H 1 1 to 5 GeV pact of the primary protonmomentum beam selected from hadrons the are SPS. mixedtions For with with a muons, the given electrons beam collimators and tune, orbeamline tertiary i.e. the is rigidity hadrons beam equipped selection, from aperture the limits. interac- withCounter a In with special order Achromatic to Ring differential Focus select Cherenkov (CEDAR)Helium the counter, [18] for wanted counter. the beam hadrons, This Cherenkov momenta the counter higher Differential uses than a 60 gas GeV as radiator, and 158 GeV has a sophisticated optical systemof that collects a and diaphragm focuses whose the openingonly Cherenkov can photons the be onto photons tuned, the from in plane the relationcounter. wanted to By species a using to given a pass gas coincidence throughcan pressure, logic, and be such 6-, get as achieved. 7- detected to or by For allow 8-beam the the fold, trigger. 8 NA61/SHINE a PMTs experiment positive of tagging the the of 6-fold the coincidence wanted signal particles is used forincident the particle are maximalwanted is hadron found peak by is performing expected.pressure a range Results pressure for of beams scan the at in gas 13 pressure the GeV scan domain performed where in the the full relevant Figure 4 pressure within the pressure range which covers maxima of pions, kaons and protons at 13 ( final setting is thevalue pressure of corresponding the optimal to pressure depends the onsince centre possible the admixtures of production in the the angle gas, wanted ofthe as Cherenkov hadron well signal radiation as peak. peaks on is and temperature, a their TheThe function separation actual of can counter be the is modified gas installed by density.divergence. in changing However The to the a make width aperture sure special of of the location theof light is diaphragm. the of collected CEDAR the with counter high beamline has symmetry,Under an to where standard angular be the operational alignment performed conditions beam each the time has detectionThe number the efficiency almost of of beam misidentified zero the particles position is detectors at lower isthe than the trigger 0.8%. better detector definition than For also changes. beam 95%. requires momenta the lower signal than20] from 40 a GeV carbon dioxide-filled Threshold Cherenkov [19, 2014 JINST 9 P06005 . c 4) / = Z ions at 5 ions. The 8 10 × 6 ∼ Ni. 56 Be has more protons ( 7 D up to 2 Be fragments are accompanied mainly 7 Be and the nuclei with a charge difference 8 B). Furthermore 9 Be and Li, – 9 – 6 5 Be are isotopes 7 3). Such nuclear configurations are disfavored with increasing nuclear mass, = N , and the desired ions produced from the fragmentation of the primary Pb beam ) Z / Be ion (“wanted ion”) was selected for the NA61/SHINE beam, because it has no long- A 7 ( b γ The selection and transport of a specific ion species from a fragmented heavy (Pb82+) ion The At low energies, a better selectivity of the wanted ions is achieved with the “fragment sep- The H2 beam optics provides a smooth focus at the target of the NA61/SHINE experiment The transport of primary ions in the H2 beamline is straightforward. The beam tune, i.e. D and He ions whose rigidity overlaps with the one of the wanted ions due to Fermi motion. ∼ 2 of one and a similar mass to charge ratio (e.g. beam for nuclear reaction experiments isi.e. not straightforward. The H2 beamlinewill selects be on mixed rigidity, with a variety ofrigidity values other within nuclei the with beam similar acceptance. mass Moreover,the to rigidity charge overlaps same occur ratios mass not and to only slightly for charge different ions ratiowhich with but smears also fragment momenta. for Without neighbouring Fermi elementsregion motion due almost the undisturbed to fragments with the would the leave nuclear same the Fermi momentum interaction motion per motion nucleon depends as on the the incident fragment Pb ions. andlight projectile The nuclear Fermi mass, fragments and by can up spread to the 3–5%, longitudinal much momenta larger for than the beam acceptance. aration” method [21], profiting fromIn the the first double spectrometer, spectrometer ions of areratio selected for the within the H2 a fragments beamline rigidity as (see valuefirst produced that figure 3). spectrometer, by a maximizes the piece the primary of wanted fragmentation material todependence target. (called all of degrader) At their is the introduced, charge. focal in pointseparated which Then according of ions in to the lose the their energy charge second in state, spectrometer which the then different can ions be selected will using be a spatially thin slit (collimator). the experiment. lived near neighbours and thus allowsions. to The make near a neighbours light to ion beam with a large ratiothan of neutrons wanted ( to all by A problematic choice of wantedwhich ion would species be would accompanied be by a stable nucleus or with long mass lived nuclei to from charge ratio of two, since a surplus of protons causespotential of a the Coulomb fewer repulsion neutrons. which As cannot can be be balanced seen by in the figure5, attractive intensity is further reduced in the H2 beamline by collimation, down to a rate of a few 10 with an RMS width slightly larger than 2 mm at the lowest momenta and 1.2 mm at 158 GeV rigidity is set to match the ionare momentum adapted extracted to from the the SPS, non-standard and (high)and the charge detectors classification of in in the the the beamline beam Experimental particles. Hall,typically the To using respect intensity a the in single the radiation (or SPS limits double) machine injection is into kept the to SPS a resulting minimum, in a total of The momentum spread is typically lower than 1%, defined by2.5 the collimator settings in Primary the and line. secondary ionThe beams physics program of NA61/SHINE(Xe) requires beams ions. of Beryllium For (Be),the reasons Argon fragmentation (Ar) of and of compatibility Xenon Pb withNA61/SHINE. ions, the LHC whereas program the the Ar Be and beam Xe is beams obtained will from be specifically produced for 2014 JINST 9 P06005 ) ) A E are / c ) and E / ∆ 2 45 left Z GeV 40 A with settings ion beams. C c c GeV/c / / 35 A GeV 30 GeV Pb beam incident on A A c B / 25 Be for data taking. at CERN SPS 7 for NA61/SHINE 20 GeV and 150 Be beam at 150 Be beam at 7 A , and 40 Be A c 7 15 / and thus a check of the purity of Pb ions per spill from the SPS is 10 c 8 GeV Li / A 5 spectra of ions for the carbon ( He GeV d ) of the ions. The latter allows mass ( , 75 0 tof A 4 3 2 5 c
/
tof 10 10 10 10 counts GeV C (open blue histogram) content. Comparison with A – 10 – 11 2 45 Z 40 C GeV/c 35 A 30 Be particles with 10 to 20 times more unwanted ions. 7 ) and time of flight ( 2 B 25 Z at CERN SPS for NA61/SHINE 20 Be to all ions is maximized (see figure5). Ion fluxes at the NA61/SHINE Be beam at 13 Be beam at 7 7 Be 7 15 10 ) peaks resulting from fragmentation of the primary Pb beam at 13.9 Li 5 He right Be (filled purple histogram) or the d . Charge spectrum measured with the Quartz Z-detector for 13 7 0 Be) is seen in the Be spectrum. We therefore decided to select 2 3 4 7
10 10 10 counts Be beam. This is illustrated in figure6 where the The optional degrader (1 or 4 cm thick Cu plate) is located between the two spectrometer During the 2011 running period the NA61/SHINE collaboration used the beamline configura- Under typical running conditions a beam of several 10 The fragment separation method was tested in 2010 with a 13.9 7 Figure 5 sections (see figure3). The composition ofwhich the measure ion the beam can charge be ( monitored by scintillator counters tion without degrader at beam momenta of 150 figure5 demonstrates that bynearly using an the order of degrader magnitude. the ratio of wanted to all ions is improved by apparatus were 5000 to 10 000 The drawback of this methodblow-up is due a to loss multiple scattering of in beam theness. intensity material of Thus due the a to degrader high nuclear which separation rises interactionsloss power with and of increasing of the thick- intensity. the beam Furthermore, fragment for separator a spectrometerenergy given goes loss degrader along thickness are both to with the a a nuclear large high cross extentincreases energy section with independent. and decreasing the This energy. means that the separation power ( focused onto the 180 mmtarget long the Pb fragmentation beam target undergoes (mostly made peripheral)resulting of collisions with mix Be. the of (light) nuclear target During fragments nuclei. its is Partfraction captured of passage of by the through the the H2 the created beamline, tuned to a rigidity such that the determination of the ionsthe for momenta lower than 20 beryllium ( shown. The carbon spectrumisotope shows ( clear evidence for two isotopes, whereas only thethe single primary Be target of the H2given rigidity beamline setting with the the charge distributions 4 resulting cmeither from thick the two degrader collimator in settings which place. optimize Figure7 shows for a 2014 JINST 9 P06005 2 Z (the lower 1380 60 c / ) peaks resulting 50 1360 GeV A right TDC channel * 25 ps spectra with the selected 40 1340 2 Z 2 Z 30 and at 13 c : the 1320 / 20 ) and beryllium ( GeV Bottom A Be ions without incurring the penalty 1300 left 7 run-013540 Entries = 3465 run-013545 Entries = 2898 10 , 19 c / C (open blue) fragments. The primary Pb beam . The spectrum of carbon is fitted by a sum of two 1280 c
0 0 11
80 60 40 20 80 60 40 20 /
Counts 140 120 100 120 Counts 100 GeV ). The spectra were measured by the A-detector. A GeV – 11 – A right 2 Z 1380 60 1360 50 Be (filled purple) and TDC channel * 25 ps 7 40 ) and beryllium ( 1340 0 10 20 30 40 50 60 2 3 1 left
10
10 10 . Counts 30 c / 1320 GeV 20 A Be ions. This choice allowed tagging pure 1300 7 : the time of flight spectra of ions for the carbon ( 10 Top . Fragment charge distributions obtained with the H2 beamline in fragment separator mode and . 1280 0 0
50 80 60 40 20
300 250 200 150 100 Counts 120 100 200 180 160 140 Counts from fragmentation of the primary Pb beam at 13.9 Gauss functions, whereas that of beryllium by a single Gaussian. (gray area) peaks of carbon ( collimator settings optimized for momentum is 13.9 Figure 7 optimised for Figure 6 on intensity from the degrader2012 while and still early resulting 2013 fragmented in ion an beams acceptable at 30 ratio of wanted to all ions. In momentum limit of the accelerator capabilities) were provided to NA61/SHINE. 2014 JINST 9 P06005 ). 0 co- X z 20 m and . 7 − ] 0 93 m, V1 . X and radiation length 6 I 0.070 0.070 1.175 0.470 1.175 1.175 1.175 3.526 2.034 0.070 [% − λ ] in 2013. I c λ / 0.025 0.025 0.635 0.254 0.635 0.635 0.635 1.904 0.562 0.025 Material budget [% GeV A 90 42 42 16 81 20 14 70 81 58 11 72 74 ...... 146 ...... 80 . 6 5 6 2 6 6 [m] 14 36 14 14 13 36 9 − − − − − − ≈ − − − − − − − ≈ − Position and 30 in 2009 (an additional interaction trigger was c c / 8 10 20 20 / in 2011, = c = = = Hole / [mm] φ GeV – 12 – φ φ φ , for which positions varied up to 50 cm depending on the p A 5 6 6 6 . . . . 10 10 10 , 19 5 2 5 5 5 2 detectors were not surveyed, therefore are known only approxi- 15 c 10 32 32 32 × × × / p × × × × × × × × and 350 GeV × × × 5 60 c 28 26 20 20 40 300 100 300 80 / 48 48 48 × GeV and 158 GeV [mm] × × = = = = × × × = c × × × A φ φ φ φ 60 / Dimensions φ 150 160 48 48 48 300 100 300 p p Typical thin target position Z A S1 S2 S3 S4 S5 V1 V0 V0 V1 BPD-1 BPD-2 BPD-3 Detector Be interactions at 13 9 23 m. Positions of the A and V0 . . Summary of typical beam detector parameters: dimensions, positions along the beamline ( +C interactions at 158 GeV 7 − Be + The locations of the beam detectors in four exemplary configurations of the beamline are − used with the S5 counter instead7 of S4 to estimate the trigger bias), of the replica target), p (c)h (a) p+p interactions at 13 GeV Colour indicates the detector function ingreen the are NA61/SHINE used trigger. in Namely coincidence, signalstrigger in of logic. red detectors in in anti-coincidence and detectors in blue are not used in the (d) (b) p+(T2K replica target) interactions in 2009 and 2010 (the S3 detector was glued to the surface 3 Beam detectors and trigger system A set of scintillation andstream of Cherenkov the counters target as provide precise wellof timing as the reference, incoming the along beam beam with particles. charge position Interaction andger counters detectors position on located located measurement downstream interactions of in up- the the target target. allow to Typical parameters trig- of these detectors areindicated summarized in in figure8. table1. These were used for data taking on (from top to bottom): employed target. E.g. for the liquid hydrogen target the positionsmately. were: BPD-3 Table 1 Positions of most of thesesequent detectors runs. varied in Exceptions time are by BPD-3, a V1 and few cm V1 due toV1 dismounting and remounting in sub- ordinates) and their material budget (in terms of the nuclear interaction length 2014 JINST 9 P06005 PSD BEAM BEAM BEAM
42 m. In the case of
. BEAM
S5 ≈ ≈ ≈ ≈ 14 − 42 m. As the time of flight . S4 S4 S4 = z 36 − = z VTPC−1 VTPC−1 VTPC−1 VTPC−1 Target Target Target Target 3 3 3 3 S3 − − − − V1 p V1 V1 p BPD BPD BPD BPD V1 – 13 – V1 p Z V0 V0 V0 S2 S2 S2 S2 BPD−2 BPD−2 BPD−2 BPD−2
THC
≈ ≈ ≈ ≈ S1 S1 S1 S1 BPD−1 BPD−1 BPD−1 BPD−1 . Schematic layout (horizontal cut in the beam plane, not to scale) of the beam detectors in four A m thickness yielding sufficient timing and pulse height resolution from the Cherenkov effect. CEDAR CEDAR µ d) c) b) a) Figure 8 configurations of the beamline, see text for details. 3.1 Beam counters Minimization of the total detector materialbeams. in A the minimal set beamline of is plastic a scintillatorThe (BC-408) major first beam concern, detector counters S1 especially (see is figure8) with located is ion upstream therefore of used. the target at position Downstream of the S2 detector two 1 cm thick veto scintillator detectors V0 and V1 are positioned resolution in low-multiplicity events has tothick) rely on is a equipped precise with reference four time, photomultiplierscounter the directly S2 S1 coupled (0.2 counter cm to (0.5 thick) the cm is scintillator. locatedprimary The just heavy second ion behind beam beams the the BPD-2 S1 detector and200 at S2 scintillator detectors will be replaced by quartz detectors of 2014 JINST 9 P06005 )). right were constructed in are shown in figure6 2 c 85/15 gas mixture. Two / 2 48mm Be) spectrum demonstrates a GeV ) V1 detector also has a 1 cm 7 2 A × Be ions and its nearest isotopes is 7 10 cm × are installed for configurations of beam 0 between and distance of 140 m. proportional signal amplitude simultaneously c 2 tof / and V1 0 GeV – 14 – particles/second) shapers based on AD817 integrated A 5 plane) the detectors are centred at the maximum of the y )) with active areas of 48 - x left m tungsten wires with 2 mm pitch) are sandwiched between ). The single isotope beryllium ( µ m aluminized Mylar. The outer cathode planes of these detectors µ 72 m, respectively. The round V0 detector has outer diameter of 8 cm bottom . 6 − 11 m and 9.80 m, respectively. They are used to select interactions of . ) with light readout from both sides of the scintillator bar by the two fast 2 = 3 z − = 5 cm . z 1 Be. It was located about 140 m upstream of the target and measured the time of 7 × 5 16 m and . . 0 ) of beam ions between A- and S1 detectors. It consists of a plastic scintillator (BC-408) 14 × tof − Each BPD measures the position of the trigger-selected beam particle in two orthogonal direc- The time of flight spectra measured by the A-detector at 13.6 ) for carbon and beryllium ions selected by the Z = resolution of 60 ps. The expected difference of z top tions independently using two planes of orthogonalis strips. induced On with each a strip plane widthfor a of charge a distribution about cluster 5 in each strips plane.above on a The average. threshold value cluster (to The is remove reconstruction defined signals frompositions as algorithm pedestal weighted a first fluctuations). with set Then, searches the of an signal average adjacent of amplitudes stripsthe the on position with strip the of signal the strips amplitudes beam is particle calculated (the for so-called the centroid cluster method). to A estimate 3-dimensional point measured at ( measured in the A-detector ( tof about 170 ps at the beam momentum of 13.6 2009. These detectors areorthogonal proportional chambers sense operated wire with planes Ar/CO (15 beam profile. 3.2 A-detector The A-detector was constructedsingle to isotope verify whether the secondary Be beam consists only of the 3.3 Beam Position Detectors The positions of the incomingof beam three particles Beam in Position the transverse DetectorsNA61/SHINE plane (BPDs) BPDs are placed measured (see along by the9( figure a beamline telescope upstream of the target. The three cathode planes made of 25 are sliced into strips of 2 mmbeam pitch which particles are at connected high to the intensities readout (aboutamplifiers electronics. were 10 In constructed. order The to width detect ofof their output output signal signals is observed about with 350 the ns. NA49 Negative shapers undershoots are practically eliminated (see figure9( and in the centre a hole of 1 cm diameter. The square (10 flight ( bar (15 central hole. Additionally two vetoline detectors a), V0 b) and c), respectively. Forpositioned. configuration b) the The Threshold S4 Cherenkov, THC, and detectorof is S5 the also detectors target (2 at cm diameter, 0.5 cm thickness) are located downstream beam particles in theparticle target. signal in the Interactions counter. in Thetransverse beam the counter to target parameters the are are summarized beam signaled in direction table1. by (the In the the plane absence of the beam PMTs, EMI 9133. The timetest resolution in of the the T10 A-detector beam was of measured the to CERN be PS about using 80 pions. ps during a 2014 JINST 9 P06005 x . c 21 m, / (top row) z ) = - 2 x − m] m m 400 400 µ µ µ BPD RMS 130 RMS 104 , 1 200 200 ) beam at 158 GeV − − 0 0 π residual [ BPD ( -200 -200 d BPD3x BPD3y -400 -400 planes independently. Distributions z m m - 400 400 µ µ y : the signal generated by a BPD pre-amplifier direction ( RMS 171 RMS 154 z 200 200 and Right z - 0 0 x – 15 – m. Differences of the RMS widths are mainly due -200 -200 µ BPD2x BPD2y -400 -400 100 ∼ 400 400 m m µ µ RMS 56 RMS 57 200 200 0 0 8 m). This observation agrees qualitatively with predictions of Monte -200 -200 ) = 3 BPD1x BPD1y -400 -400
−
direction. Plots are for the negatively charged hadron (mainly counts z : the schematic layout of the BPD detector. BPD , 2 Left . Distributions of residuals associated with beam track fits in each of the BPDs in the . − (bottom row) planes. Differences in RMS widths are mainly due to non-equal distances between the z - In order to reconstruct a beam particle track, least squares fits of straight lines are performed y BPD ( (upper curve) and the corresponding signal at the output of a shaper (lower curve). The time scale of the Carlo calculations. 3.4 Z-detectors In order to select secondarydetectors) ions were by constructed their and tested. charge These at are: the trigger level, two Cherenkov counters (Z- Figure 10 to the positions measured by the three BPDs in axis is 500 ns per division. and detectors in the by a given BPD is builtposition from of two the transverse BPD coordinates along the measured beamline. by the two strip planes and the d Figure 9 to non-equal distances between the detectors in the of residuals associated withbutions those indicate fits the are orderagreement of shown with magnitude in the of figure design the10. value accuracy of of The the RMS BPD widths measurements, of which the is in distri- 2014 JINST 9 P06005 . , c c / / the c / GeV GeV A A GeV A as the radiator 3 5mm . 2 × 40 × Be interactions. 9 Be + 7 0023 requiring a minimum gas pressure of . gas radiator. The construction of this detector 1 10 ≈ F 4 – 16 – per nucleon. For the momentum of 13 c / He peak was 18–19%. However, it was estimated that at the 4 gas at normal conditions is about 1.00142 leading to a Cherenkov 10 distributions measured by the QD for secondary ion beams of 13 F 4 2 Z per nucleon. Thus the detector performance is largely independent of the beam momentum used in the data taking on Be beams in 2011–2013. c 7 m thick aluminized Mylar foil and focused by a parabolic mirror onto a single c / / µ GeV A 88 GeV . is equipped with two photomultipliersOptical (X2020Q) grease (BC630) attached is to applied both betweengood sides the light PMTs of transmission. and the the quartz quartz plate plate. in order to achieve is based on the standardby CERN a threshold Cherenkov 25 unit. Cherenkov photons are reflected photomultiplier, Hamamatsu R2059. 0 Both Z-detectors were positioned between BPD-2 and BPD-3 (see figure8). The large refrac- The trigger is formed using several of the beam counters listedThe in core table1, of the the trigger Cherenkov logic is an FPGA (Xilinx XC3s1500) running at 120 MHz embedded Figure5 presents Both detectors were tested during the 2011 run using the secondary ion beam at 150 ≈ (i) beam logic (i) The Quartz Detector (QD) with a quartz (GE214P) plate 160 (ii) The Gas Detector (GD) uses a 60 cm long C (ii) beam particle identification (iii) interaction logic. threshold momentum of about 17.6 GeV momentum in the momentum rangefraction relevant for index the of NA61/SHINE the energy scan C program. The re- tion index of the quartzof radiator of about 1.458 leads to a low Cherenkov threshold momentum detectors for beam particle (hadrons orin ions) figure8. identification, and the PSD calorimeter, as illustrated in a CAMAC Universal Logic Module,ibility the with CMC206 the [22]. legacy CAMAC NA49 is electronics. used The for trigger backward logic compat- is divided into three main blocks: lowest acceptable value of the refraction index is The ADC signals measured in the Quartzand and He Gas Detectors beam showed well particles. separatedwidth peaks Both of to proton detectors mean performed value well ratiolowest at for beam this the momentum momentum, the namely performanceresolution the of and measured the the GD material budget willlarger (at deteriorate than the both for sufficiently in the high QD). terms gaswith of Therefore secondary pressure the the it charge QD is was about used a as factor the of Z-detector 2.5 for the physics data taking 3.5 Trigger system In designing the NA61/SHINE trigger system, particularand attention robust was paid system to capable developing a of flexible (pions, handling kaons, protons, and ions) selecting and different targets reactions as required using by a the variety NA61/SHINE of physics programme beams [1]. 1.63 bar. and 150 2014 JINST 9 P06005 ∧ BEAM T ( N ) allows for the direct INT T , ) INT ) T ∧ BEAM T ( : BEAM N T ) and interaction triggers ( – 17 – ( INT P N BEAM = TPCs: VTPC-1 and VTPC-2) are located in the magnetic T INT P Vertex TPCs: MTPC-L and MTPC-R) are positioned downstream of the magnets Main is the number of events which satisfy the beam trigger condition and ) BEAM T ( N is the number of events which satisfy both the beam trigger and interaction trigger conditions. 10 Hz. The TPCs consist of a large gas volume in which particles leave a trail of ionization electrons. An overview of the main parameters of the different TPCs is given in table2. The simultaneous use of the beam ( Analog signals from the beam counters are first discriminated with constant fraction and lead- ) ≈ INT A uniform vertical electricMylar field strips is that established are byelectrons kept a drift at surrounding with constant the field velocity cage appropriatetheir under position, made electric the arrival of potential influence time, of aluminized by andorder the a total to field voltage achieve towards number high divider the are spatial top chain. measuredone resolution plate square with the where centimeter proportional The area, chamber wire a top total chambers.of plates of the are about In track 180 subdivided signals 000 into and for pads the allpoints known of TPC’s. along pixel From the about positions the particle one recorded trajectories. gets arrival times a sequence of 3-dimensional measured determination of the interaction probability, where T 4 TPC tracking system The main tracking devices of theChambers NA61/SHINE (TPC). experiment are Two four of large them volumefield, ( Time two Projection others ( symmetrically to the beamline.two In VTPCs. addition It a is smallerangles. centred TPC Also on (GAP-TPC) the the is Low beamline mountedTPC Momentum chambers. Particle between for Detector The the measuring presented TPCs particles allow inUp with reconstruction section of the to7.2 over smallest 234consist 1000 production of clusters tracksprecise two in and measurements. a small samples single of Pb+Pb interaction. energy loss per particle trajectory provide high statistics for ing edge discriminators before enteringsignals (12 a ns width) second and discriminator, convert them whoselogic to signals role ECL levels, are is as also required to recorded by shapelogic in the FPGA in the pattern trigger the units logic logic. analysis on These of an triggerwidths event-by-event basis data. prevents for also The verifying combined the the use pile-up trigger ofnator in two is the around discriminators trigger 100 with ns, logic different while output (thedead the length time length of of of the the the trigger second output system discriminator isof of is around the 12 100 ns). ns, first Correspondingly, small discrimi- the compared to the dead time gated trigger rate Up to four different triggers cantrigger. be Different run trigger simultaneously with configurations a arefor selectable off-line recorded 12 selection. in bit a pre-scaler for pattern each unit on an event-by-event basis 2014 JINST 9 P06005 70 × 5 28 (90/10) . 1 7 2 96 1.3 × 672 173 10.2 81 58.97 4 × GAP-TPC 30 Ar/CO 40 180 × 5 × . 5 (95/5) 2 × 19 90 2.3 390 170 5 40, 5 63 360 111.74 and a height of the field cage of × 192, 128 × MTPC-L/R 2 top surface area and 0.67 m depth. 6 Ar/CO . 390 2 3 9m . 3 5m . 2 × 98 9 in the proportion 95/5. The track signals are × . × 28 3 2 0 (90/10) . × × 2 200 13 72 1.4 195 192 5 2 66.60 . 27 648 × 3 VTPC-2 – 18 – 250 Ar/CO m. The drift volume is enclosed by a gas box made of a µ s. The support of the Mylar strips is provided by tubes of ) 98 µ 16 × ( 3 (90/10) 28 × 2 200 13 72 1.4 192 195 2 66.60 × 26 886 × VTPC-1 5 . 3 250 Ar/CO s] µ m Mylar. The readout plane consists of 7 padrows with 96 pads each, the pad in the proportion 90/10 is employed. The readout is performed by 6 proportional µ 2 H) [cm] × W × . Parameters of the VTPCs and MTPCs. The pad length in the VTPC-1 equals 16 mm only in the two Between VTPC-1 and VTPC-2 an additional tracking device, the GAP-TPC [24], is located Each Vertex TPC consists of a gas box with 2 Gas mixture # of sectors # of padrows # of pads/padrow Pad size [mm] Drift length [cm] Drift velocity [cm/ Drift field [V/cm] Drift voltage [kV] size (L No. of pads/TPC The inserted field-cage structures excludewhich the the particle region density of in 0.12 Pb+Pbmixture m reactions of on Ar/CO is so either high side that of trajectories cannot the be beamline resolved. in A gas chambers on the top which providetrajectories. up More to details 72 about the measurements Vertex and and ionization Main samples TPCs on can the be found particle directly in ref. on [23]. the beamline. ItVTPCs covers and the MTPCs. gap High left momentum for tracksusing the can the additional be beam points better between measured extrapolated in the the back sensitive GAP-TPC.but to volumes Particles the measured originating of primary from the only vertex the primary in vertex high the momentum MTPCs tracks can outside beits the better material magnetic distinguished field. budget from was Sincelength. conversion minimized The the electrons design to beam follows faking that 0.15% passes of the offigure through other11). TPCs a this described The radiation above detector electric (the field schematic length layout inMylar and is the strips shown drift in 0.05% connected volume by of is a generated an resistorwith by chain. a interaction a field resulting The cage electric drift made field time from is of aluminized 10.2 about kV 50 over 58.97 cm (173 V/cm) glass-epoxy with a wall thickness ofsingle 100 layer of 125 4.1 VTPC, MTPC and GAP-TPC Each Main TPC has aabout readout 1.1 m. surface at It is the filledread top with out of a by 3 gas 25 mixture proportional ofon chambers Ar/CO each providing particle up trajectory. to The 90 accuracyfor measured of a points the particle and measurement is of ionization about the samples 4%. average ionization energy loss Table 2 upstream sectors. In the MTPCsmore the pads 5 per sectors padrow. closest to the beam have narrower pads and correspondingly 2014 JINST 9 P06005 m
µ 81.5 cm 81.5 m) gas-
µ 38.4 cm 38.4 ). right 30 cm 19.6 cm (Sketch not to scale) (90/10) like in the VTPCs. For ) and bottom view ( 2 Pads Columns Wire Gas box left
support
Beam
70 cm 70 59 cm 59 25 cm = – 19 – Support frame 0 X , 3 1390 cm. = materials minimizes the probability of secondary interaction 0 X Z , 92 g/cm 3 . 1 = ρ 03 g/cm -electrons by a factor of about 10. This is needed in order to decrease (Sketch not to scale) . δ 0 = ρ . Schematic layout of the GAP TPC: front view ( Figure 11 seal HR CT board Top plate RTV seal Pad plane Wires Columns Field cage Mylar gas box HV plate Epoxy Font−end cards (i) Tedlar polyvinyl fluoride (PVF) film (ii) Carbon Fiber M55J, (iv) Airex foam, (iii) Toray and leakage-tight Tedlar polyvinyl fluoride (PVF) film(pipes [25] to of produce 75 2.5 and m 96 length mmwere cylinder diameters), made envelopes which by gluing form the the Tedlar film He towith gas special Airex and rigid, foam light-weight protective [26]. carbon gas This fiber volumes. provides endcaps low-mass strengthened Thesealing. beam pipes pipe fixation, Use separation of of gases light-weightprocesses. and low- hermetic The used materials [25–27] include: dimensions are 28 mm by 4the mm. readout three The standard gas TPC composition front is end Ar/CO cards are used4.2 together with one concentrator He board. beam pipes He filled beam pipesreduce were the installed number in of Aprilsignificantly 2011 event-by-event fluctuations of in the track the density gas inuncertainties the volume of TPCs and fluctuation of thus reduce measurements the systematic innecessitated VTPCs nucleus-nucleus cutting in collisions. openings order in Installation to theopenings of double were the drilled wall pipes using Mylar specially envelopes developedfrom of tools getting which VTPC-1 into the prevented and inner dust VTPC-2. volume and ofpositioned debris the The around of TPCs. the material These beam openings axis into the andwall gas were thickness volume used carbon were for precisely fiber gluing rings) theVTPC providing lightweight support volumes. interface for The units the (200 lightest Hepresent beam possible pipes He technology. and beam ensuring The pipe hermetic close-to-normal structure gas was produced pressure that conditions is allow feasible to with use thin (30 2014 JINST 9 P06005 ) is flushed 2 – 20 – : the He beam pipe photo. : schematic layout of the He beam pipe installed in the VTPC-1 gas volume between the two Bottom Top . The construction is gas tight allowing separation of the working gas of the VTPCs from the Figure 12 helium used in the central pipe. In addition, during the operation an inert gas (CO field cages. through the outer envelope of thethe pipe VTPC-1, (the with protective gas gas supply volume).was lines The connected, constructed He is to beam shown maintain pipe in the installedrespect figure in overpressure to12. gradients the A in pressure special the in gaspipes. the two supply VTPCs. gas system The volumes This of He is themechanical mandatory pipes pipes stability to were when with ensure tested operating the different under mechanical modesof stability working of helium of conditions gas from the circulation the of in central the thenot pipes VTPCs. VTPCs. show to any the No excessive outer leakage They charging-up envelope which showed wasGas could good tightness observed. distort of the The the drift surface fixations field of of inby the the the pipes monitoring pipes active to of did VTPC the the Mylar volume. oxygen foils contentgas closing decreased the in to VTPC the a field VTPC few cage ppms gas. was duringat tested the The first this oxygen 48 level. contamination hours of of The purge the measured (seesame working figure level as)13 of and that oxygen remained observed constant impurity during the after operation gas before stabilization the in installation the of VTPCs the was He the beam pipes. 2014 JINST 9 P06005 ) c / -300 -350 50 VTPC-1 VTPC-2 -400 thick Mylar × 40 thin Mylar Ly × -450 fitted vertex z [cm] /h) Ly 3 2011: He beam pipe until 2010: without He beam pipe TPC window 2009-10: 2 1 2011: 30 -500 purging time [h] air – 21 – He box 20 window 2009-11: ) before the He beam pipe installation (2009 and 2010 y Ly thin Mylar Ly c -550 purge flux reduced by factor 2 6 ppm - typical level purge after 24 h of standard helium y / y cell LHT y target empty y 10 -600 standard purge flux (1 m standard purge 0 4 3 2 1
10
10 10 10 -650 oxygen content [ppm] content oxygen upstream flange . Oxygen level in the VTPC volumes during the gas purging period. 2 5 3 4 1 -700
10
10 10 10 10
events N Figure 13 . Interaction vertex distribution along the beam axis (data from p+p interactions at 158 GeV It is important to mention that the He beam pipe goes in between the two field cages and thus does not distort the driftaxis field. (data Figure for14 p+p interactionsshows at the 158 interaction GeV vertex distribution along the beam before the He beam pipewith installation helium (2009 gas and (2011 2010 data). data) and with the He beam pipes installed and filled data) and with the He beambeam pipes pipes installed reduce and the filled number with offactor helium background of gas interactions 10. (2011 in data). the volume Clearly, the of He the VTPCs by about a Figure 14 2014 JINST 9 P06005 and Am c 241 / 01 mbar via frequency . 0 ± 50 m Mylar. Nitrogen is flushed . µ C. Filters also absorb water contamination in ◦ . In normal operation, the fresh gas is supplied at – 22 – 2 (93/7) mixture at 200 /h for VTPCs and MTPCs, respectively. Fresh gas is mixed through 2 3 gas mixtures. The filters are regenerated after typically 4–6 months 2 The standard configuration for data taking at beam momentum per nucleon of 150 GeV Each system recirculates the gas with a compressor at a rate of about 20% of the detector vol- Oxygen is cleaned from the detector gas by filter columns containing active Cu-granules cho- Two bypass lines allow to start recirculation with the TPC isolated, and to replace the oxygen The VTPC and MTPC walls are made of two layers of 125 The monitoring of gas quality is one of the major tasks of the NA61/SHINE TPC gas system. mass flow controllers from pure Ar and CO ume per hour, i.e. 0.9 and 3 m sen for use withoperation the periods, using CO Ar/H filter without stopping the system.from In overpressure. case of compressor failure a safety bubbler protects the TPC Small amounts of gas canthe be flow directed controllers to are measuring followedas units. by the online Non-linearities required measurements and setting of calibration accuracy driftto drift is velocity of measure beyond and the the gas specifications fresh amplification, Each of gas of the the mixture flow gas regulators. (point systems hasDrift A It a velocity is in system is possible of figure measured a15), in drift a velocity and drift monitor the and detector four gas using gas the from amplitude drift the monitors. time TPC difference (point from a B). pair of 4.3 Magnets The two identical super-conducting dipole magnetsat with currents a of 5000 maximum A total have bending aimately power width 2000 of of mm 5700 9 and mm Tm and 5800 mm athat downstream length the of of 3600 opening the mm. in target. Their the centres Thegap are bending shape of approx- plane of 1000 is the mm maximized magnet between at yokesan the is the iron-free upper such central downstream and bore end. of lower 2 Insidecomponents coils m the reach diameter. leaves magnets up This room to a causes for 60% large of the fieldmagnetic the inhomogeneities VTPCs. field central where field the inside The at minor the coils theprobes. sensitive extremities have of volumes the of active the TPC volumes. Vertex The TPCs was precisely measuredhigher by is Hall nominally 1.5 T, infields the are first reduced and proportional 1.1 to T the inMore beam the details momentum second about keeping magnet. the the At ratio magnets lower of can beam the found momenta two in fields the ref. constant. [23]. 4.4 Gas system and monitoring The gas in thedrawing VTPCs of and one gas MTPCs system is is presented supplied in by figure 15. four independent gas systems. A schematic only 3% detector volume perculation hour; flow is in controlled purge by mode,modulation regulating the of the the full TPC compressors. recirculation overpressure rate to is 0 used. The recir- the gas. Water content isseveral reduced tens to of 10–20 ppm ppm afterwards. during the first two weeks after regeneration, and between the layers, to prevent airor from a contaminating potential the leak. TPC gas by diffusion through the walls, 2014 JINST 9 P06005 s per µ 2 N TPC envelope 2 Ar CO C. ◦ 1 O sensors. Gas purities of 2–5 ppm . 2 A /H 2 massflowmeters C recirculation control Fe photons in a proportional tube. The mixing and – 23 – 55 D safety bubbler TPC bypass line Oxygen filter compressor
. Schematic layout of one of the four TPC gas recirculation systems. The gas flow direction is pressure measurement pressure B exhaust Oxygen and water contamination in the TPC gas (point B), filtered gas (point C), and the input The gas circulation is typically started 1–2 weeks before the beginning of detector operation. The drift velocity decreases by about 1% after purge which is attributed to out-gassing of the The GAP-TPC with a volume of only about 150 l uses a much simpler gas system. About sources at 10 cm distance. The gas amplification is checked in the amplitude monitors. The Figure 15 marked by arrows next to thecan valves. be The directed letters to A, the B, measuring C devices. and D mark points where small amounts ofα the gas amplitude monitors measure the signal from monitoring equipment is temperature stabilized to better than 0 gas mixture (point D) can be measured with two pairs of O First, the detector is flushed withof fresh the gas input for 2 flow daysvelocity meters in approaches the the a purge gas stable mode. mixtures valuefor Due needs exponentially the to with several VTPCs limited and a precision days 35 time to hours constant for stabilize of the after MTPCs approximately (see purge. 28 figure hours 16). detector The material. drift This iswater compensated by contamination a increases, slight the increasethe drift of typical velocity the water decreases; argon content. content the of effect Also, is several when the tens on of the order ppm. of The 1% change for is slow (about 0.000220 cm/ l/h of fresh gas mixture isis flushed also through passed this through detector. a The drift gas velocity coming monitor. out from the GAP-TPC oxygen and about 20–100 ppm water are typically achieved. day) and is taken intomeasurements and account more in precise off-line the drift drift velocity velocity determinations. calibration based on the online drift velocity 2014 JINST 9 P06005 . The disap- 4 10 · 5 s in the GAP-TPC. ≈ µ : change of the drift velocity in the MTPCs after s in the MTPCs and 1.3 cm/ Right 0. Note that the vertical scale is expanded by a factor 2 µ – 24 – = t 90/10 in the VTPCs and GAP-TPC, and 95/5 in the MTPCs. 2 s in the VTPCs, 2.3 cm/ µ contents by 0.1% at time 2 : drift velocity after purge measured for VTPC-1 (circles) and VTPC-2 (squares). The curves Left . The gas composition is Ar/CO One FEE channel is dedicated to each readout pad, pre-amplifies the signal and stores the The TPC FEE system [28, 29] was inherited from NA49 along with the TPC system. 4.5 TPC Front End Electronics The electron trace of the tracktion ionization planes in of the the TPC TPCs, gas which driftsthrough are in the operated the gating in electric field the grid to proportional andmultiplication the amplification on the amplifica- range. the cathode After sense passing grid, wires the of the drifted field electrons and get sense amplified wire by plane gas by about electron with respect to the left plot. The higher argon content in theout MTPCs is the required longer to drift obtain length highervelocities drift (the are velocity safety 1.4 necessary limit cm/ to on read the drift high voltage is about 20 kV). Typical drift analog charge of a given time sampleused. in It a is capacitor array. also 256 possibleby time to a slices use global with clock 512 200 for ns time the time slices full binshandled with TPC are by system 100 each ns in FEE order time to card, bins. eliminate thusthe relative The the analog phase time full charges shifts. are sampling TPC 32 stored system is channels in are comprises driven ADC the about on capacitor 6000 the arrays TPC card, their FEE and digitization cards. is the performed digitized After via charge a values Wilkinson are forwarded to the readout electronics. the reduction of CO pearance of this amplified electron signalsignal on on the the sense two-dimensionally wires capacitively segmentedReadout induces pad of an the plane opposite-sign charge just signal behind ofinformation the the pads on field in the and consecutive particle short sense trajectories time traversing wireis intervals the provides plane. performed the 3 by TPCs. dimensional the The TPC electronic Front readout End of Electronics the (FEE). pads Figure 16 show the exponential dependence fitted to the data. 2014 JINST 9 P06005 ) 2 c / and left , re- ( 2 y c c / / 6 MeV . Results . T 0 p ± 1 MeV . 8 0 . ) charged parti- and ± 3 left y particles from their . 0 S is shown in figure 20. K c candidates found in p+p and 9 / . The magnetic fields were 2 0 2 S c c , respectively. K / / c / 2 MeV ) and negatively ( ± right and 158 GeV c / are in reasonable agreement with the PDG candidates in p+p interactions at 20 GeV 0 S 2 c K calculated for different particle species. / dx / – 25 – dE 1MeV . are plotted in figure .17 The measured peak positions 0 for negatively charged pions produced in p+p interactions c / ± T p 3 . is shown in figure 18. The measuring resolution of pion rapidity and 498 . c 2 is illustrated in figure .19 The resolution was calculated as the FWHM 2 and 158 GeV c / c T / c / p , respectively. The FWHM values are 17 / 2 c ). The curves show the result of a fit with the sum of a Lorentzian function for the / 6 MeV 6MeV . . right 0 ( 1 MeV 497 c . ± and 158 GeV / 0 / c = and transverse momentum / ± . Invariant mass distribution of reconstructed 0 S y 3 K . m The specific energy loss in the TPCs for positively ( The track reconstruction efficiency and resolution of kinematic quantities were studied using The quality of measurements was studied by reconstructing masses of 8MeV . decay topology. As an example the invariant mass distributions of 0 of the distribution of the difference between the generated and reconstructed transverse momentum presented in figures 18 and track19 selectionwere criteria obtained used forregions in negatively where the charged the pions data reconstruction efficiency passing analysis drops the [32], below event 90%. including and rejection of the azimuthal angle at 20 GeV cles as a function of momentumCurves show measured parametrizations for of p+p the interactions mean at 80 GeV a GEANT3 simulation oftracks the to detector their [30]. reconstructed partners. Estimatesrapidity As were examples, obtained the by reconstruction matching efficiency as of a generated function of 4.6 Physics performance Several examples of the physics performance of thewere TPC obtained system from are calibrated presented in data. this Details section, on which the calibration procedure can be found in ref. [31]. interactions at 20 GeV 496 value spectively. The red dashed verticalset line for marks a the total bending PDG power value of of 1.1 Tm 497.6 MeV and 9 Tm at 20 GeV and 498 Figure 17 signal and a second order polynomial for the background. The fitted peak positions are 496 and 158 GeV V
2014 JINST 9 P06005 efficiency [%] [%] efficiency (5.1) 100 99 98 97 96 95 4 , respectively. y c / 97 3 96 98 98 158 GeV/c 99 99 99 98 98 and 158 GeV c / 99 99 99 99 99 99 97 98 2 99 99 99 99 99 99 99 99 98 99 99 99 99 99 99 99 98 . 100 1 1 99 99 99 99 99 99 99 98 97 − , measured in the TPCs: p 2 99 99 99 99 99 99 99 99 100 ) total surface (see figure 21) are placed behind 2 tof 99 99 99 99 99 99 l 2 100 99.5 99 98.5 98 97.5 97 96.5 96 95.5 95 100 100 100 ( 0 4 1 0 2 0
y
c
99 99 99 99 99
– 26 – 1.5 0.5 100 100 100
T p [GeV/c] 2 p 99 99 99 99 100 100 100 = 3 97 96 2 m , and momentum, l 99 20 GeV/c 98 96 ) as a function of pion rapidity and transverse momentum. The mag- 99 99 99 98 right 2 ( c 99 99 99 99 98 98 / 99 99 99 99 99 97 98 98 1 99 99 99 99 99 99 98 97 99 99 99 99 99 99 98 98 100 ) and 158 GeV 99 99 99 99 99 99 99 98 98 , with the track length, 0 left 1 0 . The reconstruction efficiency of negatively charged pions produced in p+p interactions at (
tof
98 97 0.5 1.5 T c
/ p [GeV/c] The particle’s mass squared is obtained by combining the information from the particle’s time the MTPCs. The trackcontains length 891 of individual particles scintillation produced detectorsphotomultiplier in with tube glued the rectangular to dimensions, target the is eachto short about having the side. a 14 photocathode The single meters. diameter, scintillators a havethe Each a height shortest wall thickness of scintillators of 34 23 mm positioned mmoperating and closest matched voltage horizontal to for width the the of PMTs beamline 60,For in and the 70 the the ToF-L, ToF-L or photomultiplier is longest signals 80 about mm, on entercustom 1600 constant-fraction with the V made), discriminator and far modules housed in (CFD, end. in the KFKI VME ToF-Rpassed crates The is through (WIENER) around where 1300 the V. the actual analoganalog-to-digital discriminator signals converters are units. (96 split channel before One ADC being LeCroy output 1885F) signal while is the directly other sent signal to passes first FASTBUS of flight, 5 Time of Flight systems Since particle identification based onlycrossover on region energy of loss the measurement Bethe-Blochparticle can curves, identification not NA61/SHINE be by also performed Time uses ininherited of additional the from Flight and NA49. (ToF) independent detectors. Inphysics needs, The order a ToF-L to new and forward extend detector ToF-Rjust the (ToF-F) detectors behind was identification the constructed. were MTPCs. of It is NA61/SHINE placed to between the satisfy ToF-L/R, neutrino 5.1 ToF-L, ToF-R Two walls, ToF-L(eft) and ToF-R(ight), of 4.4 m netic fields were set for a total bending power of 1.1 Tm and 9 Tm at 20 GeV Figure 18 20 GeV
2014 JINST 9 P06005
T
10 resolution) (y
× resolution [MeV/c] [MeV/c] resolution p 3 ) as a function 40 35 30 25 20 15 10 5 0 50 45 40 35 30 25 20 15 10 5 050 45 0 4 4 right ) measurements for y ( c / 6 6 24 16 bottom 8 6 3 3 12 14 36 35 28 18 9 7 21 11 31 23 13 44 33 33 28 16 158 GeV/c 158 GeV/c 7 5 41 47 32 20 18 15 12 35 30 33 36 36 24 14 2 2 ) and 158 GeV 6 4 3 11 34 26 22 19 30 30 33 33 34 28 20 14 10 57 . The magnetic fields were set for a total left ( T 5 4 3 3 7 21 11 26 24 16 12 12 12 13 10 38 26 18 c p / , respectively. c 6 6 8 9 9 9 1 8 7 6 5 4 4 4 3 1 11 12 13 10 / 5 6 8 8 8 8 8 6 6 5 4 3 3 10 13 13 12 10 8 8 7 5 4 3 2 6 8 9 10 10 12 12 12 16 12 10 40 40
) and transverse momentum ( 1 1 0
y 0 0
3
T
T – 27 –
1.5 0.5 1.5 0.5 p p and 158 GeV c / 4 8 3 3 20 GeV/c 20 GeV/c 7 5 13 20 15 13 , scaled by 10 top 8 6 17 28 22 18 17 26 24 18 2 2 7 8 7 8 6 4 11 12 15 16 19 10 15 10 5 6 7 8 9 7 5 4 4 11 15 16 16 16 10 12 1 7 5 3 5 6 6 8 8 9 1 11 13 14 29 20 20 13 5 4 5 6 7 8 4 11 24 39 30 26 19 14 10 10 13 16 5 3 4 4 5 5 5 6 8 54 58 40 30 23 14 10 14 16 0 0
1 1
0 0
. Resolution of rapidity (
0 T T
0.5 1.5 0.5 1.5 [GeV/c] p [GeV/c] [GeV/c] p The calibration procedure is based on extrapolation of the tracks reconstructed in the MT- The overall time resolution of the ToF-L/R system is estimated based on the distribution of the Figure 19 PCs into the area offor appropriate the signals ToF in detectors, the identifying correspondingtions scintillators TDC are performed and they depending ADC extrapolate on channels. charge toeach Afterwards deposition and and detailed scintillator. checking relative correc- Corrections position for of the theposition incident position of particle of the in the beam main particle interaction in (in the S1 case counter of are thick also targets) done. differences and between the measured time of flight for particles identified as pions and that predicted negatively charged pions produced in p+p interactionsof at pion 20 rapidity GeV and transverse momentum.of Here the resolution differences was betweee calculated the as generatedbending and the power reconstructed FWHM of y of and 1.1 the Tm distribution and 9 Tm at 20 GeV through the discriminator unit and isTDC then LeCroy sent 1775A). to time-to-digital For converters ToF-R (64(96 the channel channel PMT FASTBUS ADC signals are LeCroy firstStr138) 1882F) split, followed while by then the a one other TDC line (64TDCs line is channel is sent goes FASTBUS provided to TDC into by an LeCroy a ADC the 1772A).signal FASTBUS S11 The comes CFD PMT start from (Struck of the signal DIS CFDs for the if the upstream their S1 input beam is above counter a (scintillator) threshold. while the stop 2014 JINST 9 P06005 c / 3 3 3 (up to 5 GeV c / ) charged particles as 60x34x23 mm 80x34x23 mm 70x34x23 mm left Scintillator dimensions: . Curves show parametrizations of the c / distribution is plotted as a function of ) and negatively ( 2 measurement (the intrinsic ToF detector m right tof – 28 – information) and pions and protons for even higher 190 cm 190 dx / dE ). left , ) shows mass squared as a function of particle momentum for p+p . Schematic layout of scintillators in the ToF-R detector. left , bottom . The standard deviation of the c top /
Figure 21 119 cm 119 calculated for different particle species. dx . Specific energy loss in the TPCs for positively ( / information is used along with dE This resolution allows to separate pions and kaons for momenta up to 3 GeV tof momentum in figure 22( interactions at 80 GeV if momenta. Figure 22( from the measured momentumdescribed and by trajectory a assuming Gaussian the where,observed pion for in mass. ToF-L, p+p while and The a Be+Bethe standard distribution collisions, time deviation can a resolution of be standard 80 includes ps deviation all was of contributions observed 95 to for ps ToF-R. the was This value for a function of momentum measuredmean for p+p interactions at 80 GeV resolution as well as the start detector resolution, uncertainties in tracking, etc.). Figure 20 2014 JINST 9 P06005 ) with . Each 2 informa- ) detectors tof right 120 cm × Bicron BC-408 ) and ToF-F ( left distribution as a function of particle momentum 2 photomultipliers Fast-Hamamatsu R1828, for m 00 . The lines show the expected mass squared values for c / – 29 – ). right , a large fraction of the tracks are produced by low-momentum particles c : the standard deviation of the / . They are staggered with 1 cm overlap to ensure full coverage in the ToF-F ) and the ToF-F ( 3 Bottom left : mass squared versus momentum measured by ToF-L/R ( 5 cm . 2 Top × . 10 Due to aging of the electronics two upgrades are foreseen. The HV supply will be partially The ToF-F consists of 80 scintillator bars oriented vertically (see figure ).23 The bars were × Figure 22 for particles produced in p+p interactions at 80 GeV different hadrons. for the ToF-L/R ( replaced and an upgrade ofsystem, the ensure readout its electronics long-term functioning, is and planned. also improve This the should, quality modernize of the the obtained whole geometrical acceptance. This configuration provides a total active area of 720 tion, primarily the resolution. 5.2 ToF-F The NA61/SHINE data taking for thefication T2K in neutrino a oscillation experiment phase requires space particle regionproton identi- which beam is at not 31 covered GeV by the ToF-L/R. When operating at the T2K scintillator bar is reada out total on of both 160 sides readout with channels. 2 The scintillators are plastic scintillator ( which exit the spectrometer betweenthe the forward ToF-L and ToF (ToF-F), ToF-R. was An thereforedownstream additional end constructed time of to the of provide MTPCs flight full (see detector, figure1). time of flight coverage oftested the and mounted inplaced groups on of the left 10 side120 on and independent half frames on (modules) the out right side of of which the half detector. were The size of each scintillator is 2014 JINST 9 P06005 , 0 0 t t
, has an offset, coaxial cables. In 10 cm 10 t
Ω
cm 120 distribution accordingly. In a first π t − t = tof
– 30 –
721 721 cm (top view) (front (front view) . The schematic layout of scintillators in the ToF-F detector.
Figure 23
120 cm 120
Most of the electronics for the ToF-F were inherited from the two NA49 Grid ToFs [33] which were not used since their1700 V acceptance supplied coverage by is LeCroy1461 marginal.signals independent are Each transported 12-channel PMT from high the channel voltage ToF is to (HV) operated the cards. counting near house by The 26 analog m RG58 50 a scintillation rise time ofmaximal emission 0.9 ns, wavelength is a about decay 400 nm timetail perfectly PMMA matching of the (Poly 2.1 PMT methyl ns spectral methacrylate) and response. light-guidesbars attenuation Fish were and length glued light-guides of on were both 210 wrapped cm. ends inguide for aluminium Their and the foils readout. to covered ensure The with lightbetween reflection black the towards PMTs plastic the and light- the foils light-guides a andPMT 3 and mm tape. light-guide thick is silicone inserted cylinder In matching at the the order diameter interface. of to the ensure proper optical contact order to obtain fast logicresponse signals the and cables not are plugged be into influenced ConstantVME by Fraction module). the Discriminators At (16-channel variations the KFKI input in CFD5.05 these amplitude includethe an of internal integrated the passive charge divider PMT of and 1:3 to timeoutput. provide measurements, the signals respectively, for In and order the to necessarychosen between minimize delay the the lines PMT at outputs crosstalk and their ofchannels the the CFD serve inputs. as neighbouring The “stop” channels output signals signals anby for of appropriate the the the fast CFDs order time beam of is of counter the flight PMT- S1LeCroy measurements. of FASTBUS the Time-to-Digital The central Converter start trigger (TDC) signal system. unitsrange is The digitizing with provided time the a measurement time sampling is in carried timeAnalog-to-Digital 12 out Converter of bits by (ADC) 25 dynamic units ps. into 12which The bits. is analog The specific signals time to of measurement, each thewas therefore channel PMTs carefully as are adjusted it converted on by depends aparticles channel are LeCroy on pions by cable and channel length, shifting basis the PMT by mean first gain value assuming of or the that CFD all response. produced 2014 JINST 9 P06005 3 10 × t [ps] ∆ =109.9 ps 2 / σ mean=109.1 ps – 31 – , and good transverse uniformity of this resolution. The ) GeV ( E p / -2 -1 0 1 2 110 ps. 0
). The intrinsic resolution of the ToF-F was also determined (see fig- ≈ 600 400 200 60% Entries < ps 2 right E √ 155 / E = σ tof σ . Distribution of the difference between a particle’s time of flight measured independently by the resolution of about 110 ps for a single measurement. The mass-squared distribution and its standard deviation as a function of momentum are pre- tof PSD is a fully compensating modularrequirements. lead/scintillator hadron calorimeter [34, 35] and meets these 6 Projectile Spectator Detector The development and construction oftant the forward upgrades hadron of calorimeter the wasSpectator NA61/SHINE one Detector of experimental (PSD). the setup. most The impor- This purposetator energy of calorimeter in the is nucleus-nucleus calorimeter called collisions. is theof The the PSD projectile Projectile measurement is spectators) of used collisions projectile to at select spec- surement the central of trigger (with level. a the small Moreover, energy number theinteracting carried precise nucleons by event-by-event from mea- projectile the projectile spectatorslution with enables of the the the precision PSD of extraction is one important ofexpected nucleon. for to the the The be study number high sensitive of of to energy fluctuations propertieshadron-resonance reso- in nucleus-nucleus of matter. collisions the Namely, which phase the are transition PSDby between provides the the the variation quark-gluon of precise plasma the control and caused number over by of fluctuations variation interacting caused of nucleons the and collisionergy thus geometry. resolution, excludes Basic the design “trivial” requirements fluctuations of the PSD are good en- Figure 24 overlapping scintillator bars of thea ToF-F detector. The width of the distribution is about 155 ps, indicating iteration, this method allows to discriminate pionsonly from pions. protons and was then repeated by selecting sented in figure 22( ure 24). This was achieved byand selecting plotting particles the time that difference hit between thea the region resolution two where signals. the scintillators The overlap Gaussian fit to the distribution gives 2014 JINST 9 P06005 2 c / .A 2 GeV 20 cm A × ). In order 120 cm ) and the fully × right centre and weight of 120 kg each. Such 2 ), consists of 60 pairs of alternating ). The central part of the PSD consists 10 cm left centre × – 32 – ), schematic view of single module ( left ). right . The PSD: schematic front view ( m. This tube was inserted for data taking with ion beams of momenta larger than 40 Each module, schematically shown in figure 25( Light readout is provided by Kuraray Y11 WLS-fibers embedded in round grooves in the µ scintillator plates. Thetiles WLS-fibers are from collected each together in longitudinaloptical a section connectors single at of optical the 6 connector downstream at consecutivelongitudinal face the scintillator segmentation of end into the of module 10 the is sectionsmodule module. read and ensures delivers Each out good information of by on uniformity the the a of typeTen 10 single photodetectors of light photodiode. per particle collection module which The caused are along the placed the observed atelectronics. particle the A shower. rear photograph side of of the the fully module assembled together calorimeter with is the shown front in end figure 25( fine transverse segmentation decreases thereconstruction spectator of occupancy the in reaction one plane.modules module with The and a outer weight improves of part the 500 of kg each. the PSD consists oflead 28 plates large and 20 scintillator tilesis with tied 16 mm together and with 4 0.5 mm mmtape thickness, thick and steel respectively. box tape The and are stack placed spot-welded ofof in together plates the a providing modules box appropriate corresponds made to mechanical of 5.7 rigidity. 0.5 nuclear mm The interaction thick full lengths. steel. length Steel to fit the PSD transverse dimensionsNA61/SHINE to the target region and populated the by calorimeter spectatorsenergy. the is distance increased between Interactions from the of 17 m spectatorshelium to upstream 23 tube m of with of the increasing length PSD collision housing 5.5 were the m minimized MTPCs. and by diameter The the125 entrance 125 installation cm and of between exit a Mylar the windowswhen upstream of the PSD distance the between face tube the had and target and a the the thickness PSD hut of was6.2 about 23 m. PSD photodetectors The longitudinal segmentation of theper module calorimeter for modules the requires signal 10 readout. individual Silicon photodetectors photomultipliers SiPMs or micro-pixel avalanche pho- Figure 25 6.1 Calorimeter design The PSD calorimeter consists of 44 modules which cover a transverse area of 120 assembled detector ( schematic front view of the PSDof is 16 shown small in modules figure with25( transverse dimension of 10 2014 JINST 9 P06005 ), depen- left Hz. The average Hz. To check the 5 5 ) and on the number of . Such a limited number 2 centre and higher is achievable. The 2 mm pixels/mm / 3 4 active area fits well the size of the WLS-fiber 2 3 mm – 33 – × . Their 3 2 ). left ). right in a single photodetector. 5 , see figure 26( . Performance of MAPD-3A photodiodes: dependence of gain on the bias voltage ( 4 10 Since the PSD calorimeter has no beam hole to ensure maximum acceptance for the spectators, The MAPD-3A photon detection efficiency (PDE) for the Y11 WLS-fiber emission spectrum × amplitude in one longitudinal section of aTherefore, PSD module an is important expected to requirement be for aboutleast 1500 the photoelectrons. in calorimeter the readout central is region. amust high In be count fast particular, rate enough the capability, to recovery at count deliver time stable rate of amplitudes capability the at of selected signal the MAPD-3Apulses frequencies MAPD-3A photodiode was up measured. the to The dependence 10 stability of of its the amplitude amplitude of on the the pulses at frequency different of operation light frequencies Figure 26 the central part of the PSD is exposed to ion beams with intensities up to 10 todiodes, MAPDs [36, 37] are aninternal gain, optimum compactness, choice low cost due and to immunity theirhadron to the remarkable calorimeter nuclear applications properties counter have such effect. some as Moreover, specific forward high linearity requirements of such the as large photodetector dynamic responselinearity range of to and MAPDs intense are limited light by pulses. thewith finite individual number However, surface of the pixels. resistors dynamic Most have range of a the and pixel existing types density of of MAPD 10 reaches 15% at 510 nmdifferent samples and of is MAPD-3A similar detectors rangesis to from 4 the 65 V performance to of 68 V. PMTs. The maximum The achieved gain operation voltage for dence of signal amplitudeincident (in photons arbitrary ( units) on the count rate capability ( leads to serious restrictions ofphotons MAPD is comparable applications and in even calorimetry, largerphotons than where hit the the the pixel same number number. pixel, of The leads effect tointensity. detected of significant non-linear saturation, Evidently, MAPD when the response a to MAPD few lightthan has pulses the with linear number high response of incident only photons.to if the This the traditional feature PMTs. number represents However, of a this drawback disadvantagemicro-well pixels is of structure is essentially MAPDs reduced [36], much compared for larger for MAPDs withabove which individual considerations a motivated the pixel choice of density photodiodesPhotonics of of type Inc. 10 MAPD-3A (Singapore) produced by [37] Zecotek have for a the pixel density readout of 15000/mm ofbunch the from PSD one longitudinal hadron section calorimeter. ofmore the than These 10 PSD modules MAPDs and provides a total number of pixels of 2014 JINST 9 P06005 : energy . Taking 4 ). As seen, 10 Right × right , on the pion energy is shown in E / ). As seen, the MAPD-3A amplitude E σ centre – 34 – transverse size is too small to contain the entire hadron 2 , of the tested PSD prototype as a function of hadron beam energy. E 30 cm / E × σ 3 array) was assembled and tested in the H2 beamline using hadron beams × momentum. The calibration of all readout channels was done with a muon beam. c / : energy resolution, ). Left left . The dependence of the measured energy resolution, In order to check the photodetector linearity, measurements of MAPD amplitudes were per- The reported comprehensive studies confirm that the selected MAPD-3A photodetectors sat- The tested prototype with 30 Figure 27 The solid line is a fit to the experimental data points by the function shown in the inset. shower. Therefore, a non-negligible lateralconfirm shower that leakage about is 16% expected. ofof the Monte hadron Carlo shower shower simulations leakage energy on escapes from the the energy tested resolution array. was The influence studied in refs. [38, 39], where a third term in spectrum measured in the first sectionof of muons the and central positrons. module for a 30 GeV hadron beam containing a fraction of the light emitting diode wasproduced checked by by a the normal MAPD-3A PMT. is The presented obtained in behavior figure of the26( amplitude of 20–158 GeV The energy resolution of the tested array was estimated from data taken with the hadron beams. formed with light pulses of differenta intensity. reference The photodiode number with of known incident quantum photonsthe was efficiency MAPD and determined amplitude by gain on equal to the one. number The of dependence incident of photons is shown in figure 26 ( isfy the requirements of theinstalled NA61/SHINE in experiment. the 44 At PSD present,physics modules with 440 and beryllium MAPD-3A show and detectors stable proton are operation beams. during data taking for6.3 calibration and Performance of the PSD calorimeter In order to checkbeams the of performance various of momenta. thenine During calorimeter, small the several modules first (3 tests stage were of performed the with R&D hadron (in 2007) a PSD module array of would drop about 5% for the maximum beam intensity foreseen. the MAPD linearity is preservedinto for account light the pulses different photon withthe detection number same pixel efficiencies of density of photons as about the up15000 MAPD-3A 25% to photoelectrons. type), for 6 the the linear tested response is MAPD expected (with for amplitudes up to figure 27( 2014 JINST 9 P06005 Be colli- 9 Be ions in 7 ) distinguish Be + 7 top with and without c / GeV A Be beam was used other 7 ). The right-side peak in the right protons as a function of the module c / ) without cut (red) and with cut (blue) on left Be collisions the PSD was also used in the trig- 9 is about 6.5%. c – 35 – : PSD energy distributions recorded during the data taking / Be + 7 Right . Spectra are shown for the beam trigger (blue) and for the interaction c / GeV A . Spectra are shown for the beam trigger (blue) and interaction trigger (red). ) shows the measured energy of 158 GeV beam ions is shown in figure 28( c / c top / Be ions by the Z-detector. : PSD energy distributions for the secondary ion beam at 75 7 ) shows the PSD energy spectra recorded during the data taking for GeV Left GeV A positively charged H2 beam is shown in figure 27( Be interactions at 75 . A 9 c right / Be peak in the amplitude distribution of the Z-detector. Clear identification of During the 2011–2013 data taking for The spectrum of deposited energy in the first section of the central module exposed to the Figure 29( Be + 7 7 the ger for online rejection ofions the were most also peripheral present events.ter in As by the a 75 secondary beam. The distribution of the energy deposited in the calorime- Figure 28 30 GeV selection of the for trigger (red) events. addition to the stochastic andThe constant fit terms of the was experimental added data with ingives the the the three-term parameterization coefficient formula, of assuming of a the the fixed stochastic leakageThe resolution. term term non-zero of equal constant 16%, to term 56.1% might be andnot an of provide indication the full that constant compensation. the term selected equal lead/scintillator to sampling 2.1%. does spectrum corresponds to full positron energybe absorption regarded in as the an first electromagnetic longitudinal calorimeterlead section with absorber which coarse (96 can mm) sampling. compared Due to tosorbed the the in scintilator large the tiles thickness lead (24 of and mm) only mostthe about of energy 0.7 the resolution GeV positron for is energy deposited positrons is in at ab- the 30 GeV scintillator plates. As a consequence, the fragmented beam isure seen28( here as well as contamination of deuteron and helium ions. Fig- sions at 75 number on which thedifferent beam energy reconstruction was methods centred. by colour.modules, Histograms Red while corresponds and to blue curves the is energy inspot. sum for figure As of the seen,29( all the sum PSD mean ofcases. values of the reconstructed corresponding energies are clusters close of to the modules real around beam energy the in beam both 2014 JINST 9 P06005 ) c ≈ / z top left , for 158 GeV E / E σ ). bottom right , obtained for each of the 44 modules E / ). Energy resolution, proton energy in the PSD modules ( E c σ / top right – 36 – . The boiling rate in the liquid hydrogen was not mon- 3 07 g/cm . present in the target after removal of liquid hydrogen was esti- 0 protons. The small variations in the energy resolution can be ex- GH = c ρ / LH ρ ) presents the energy resolution, bottom . Mean values of reconstructed incident 158 GeV Figure 29( 581 cm. In data taking on p+Pb interactions the target was surrounded by the LMPD detector. protons (bottom left) and distributions of resolution for the 44 modules ( Figure 29 and distributions of mean values for the 44 modules ( − 7.1 Targets For data taking on p+p interactionsteraction the length) liquid and hydrogen 3 target cm (LHT) diameterfilled of was 20.29 with cm placed length para-hydrogen 88.4 cm (2.8% obtained in- upstream75 of in mbar overpressure the a with VTPC-1. respect closed-loop to The liquefactionliquid the target hydrogen atmosphere. system was density At is which the atmospheric was pressureitored operated of during 965 at mbar the the data takingData and taking with thus inserted the and liquid removedculate hydrogen liquid a density hydrogen data-based in correction is the for known LHT interactionsdensity only was with of approximately. alternated material gaseous in surrounding hydrogen order the liquid tomated hydrogen. cal- from The the ratio of high multiplicity events observed in a small fiducial volume around the plained by the precision oftests the and energy with calibration. the MC These simulations. results are consistent with the prototype 7 Targets and LMPD The targets used by NA61/SHINE are positioned upstream of the VTPC-1 and centred at from the scan with 158 GeV 2014 JINST 9 P06005 . 3 at × × LH Be. 3 ρ 9 / 5(H) 5(W) GH . . . ρ 2 ) 83 g/cm . I 1 λ × ( = ρ 5(W) . Pb). The target density was 11.34 g/cm a thin graphite target of dimensions 2 C and dimensions were 2 ◦ 204 c / . The targets consisted of more than 99.4% , placed in an aluminium container filled with he- 3 3 – 37 – at 20 3 Pb, 1.4% 84 g/cm 3(L) cm . . 206 1 0 85 g/cm . = × 1 ρ Be collisions in the period 2011–2013 two beryllium targets were = 9 5(H) . ρ 2 Pb, 24.1% Be + × 7 207 and density 5(W) 3 . and 2 Pb, 22.1% +C measurements at 158 and 350 GeV 3 2(L) cm π 208 × For hadro-production measurements also a thick graphite target, a replica of the T2K target, For data taking on For data taking on p+Pb collisions a special thin Pb target disc was used in order to reduce in- For C with a molar mass of 207.2 g/mol. The target disc was placed in a Tedlar [25] foil container ◦ 2(L) cm 5(H) . . lium gas, was employed bysurements NA61/SHINE. of interest The for same the target T2Kinformation was neutrino about oscillation used primary experiment for interactions in hadro-production Japan. of mea- target In protons along these on the measurements carbon beam was axis was extracted. equivalent to The about thickness 4% of of this a nuclear interaction length was used. It consists of a 90 cm long rod with a radius of 1.3 cm and a density of 2 target absorption of slow protons which are measuredtagging. by the Two LMPD different and are target used thicknesses, forstudy event 0.5 centrality of mm in-target and absorption 1 of mm, slowa were protons. diameter used The of to transverse 1 allow shape cm. an of(52.4% experimental The the target target was material circular, purity with was 99.98% lead with natural isotopefilled composition with atmospheric pressure heliumin gas the in vicinity order of to the reduce target.for background The reference of target data off-target was taking collisions removable with frominteractions. the the beamline target using removed a needed pneumatic to piston estimate background due to off-target target centre for data taken withvaried inserted within and the removed liquid range hydrogen. 0.4–0.6%. Theless The density typical at ratio absolute higher uncertainty and of more thisthe at ratio LHT lower is varied beam during 0.1 momenta. the at data-taking 40 This GeV/c, period. indicates that the operational conditionsused. of Their density was The most abundant contaminant werean oxygen aluminium nuclei container (about filled 0.4%). with The atmospheric pressure Be helium targets gas. were placed in 20 The replica and the actual targettarget of is T2K surrounded are by shown aluminium in flangesthe figure which target30 . are holder The inserted allow upstream into to part a alignbeam of target the axis the holder. is target graphite Three parallel equivalent screws to to in about thewas 1.9 beam placed interaction axis. at lengths. The around The target 50 downstream cmreplica thickness face target from along of allow VTPC-1. the the to replica Hadro-production constrain target thethe measurements target contributions taken (for from with details primary the see and T2K [40]). secondary interactions within 7.2 Low Momentum Particle Detector In hadron-nucleus interactions the collision centralitylow can momentum be protons deduced (the from so-called theMomentum grey number protons). Particle of Detector For emitted (LMPD), this was purposesize a constructed TPC special [41]. detector, chambers the The on Low detectordetection the layers consists picking two of up the sides two ionization small signal oflayers of the radially plastic emitted absorber target particles. layers Between with are the inserted. a detection Therefore vertical the drift range field, of particles and in a the detector sequence material of 1 2014 JINST 9 P06005 ). The ionization : schematic layout of left Bottom ). The signal of protons with right – 38 – ) shows the distributions of interaction vertex coordinates bottom : technical drawing (side view) of the replica target used during the NA61/SHINE data Top . The final version of the LMPD, see figure 31 along with table3, was manufactured in 2011, The operational parameters of the LMPD were optimized during the 2011 test. In particular, a taking consisting of a 90 cm long graphite rod and aluminium support flanges. Figure 30 can be determined. The range andtype, energy and loss therefore by event-by-event ionization counting of of apossible. the particle number Prototypes depends of of on emitted the its low detector energy energy were and protons tested becomes in 2009 and 2010. and was first tested intector, the in NA61/SHINE parasitic experimental mode. area, downstreamcapability The of of tests the proton showed NA61/SHINE the de- identification expected andevent overlayed performance of with of counting the the reconstructed the clusters detector, low and namely energy tracks its is (grey) seen protons. in figure A32( typical raw gradual decrease of amplification in the layers close to the target was introduced. This is necessary the complete geometry of thethe T2K replica target. target. The overlaid red rectangle represents the simplified geometry of produced by particles with fixeda range selected is penetration shown range innuclei. is figure The clearly( 32 cluster visible reconstruction uses along astruction with closest uses neighbour other the search Hough fragment algorithm, transform while procedure species the combinedpattern such track with the recon- recognition. as maximum likelihood helium Figure principle for 32( reconstructed from LMPD tracks fortarget events (blue recorded histograms). with inserted The (redand signal histograms) the of and contribution events removed from from non-target interactions interactions is in small. the Pb target is clearly visible 2014 JINST 9 P06005 p+Pb physics c / 5 . 22 6 × 2 × (85/15) 5 ) 4 . × 2 10 0.9 140 195 20.5 2 15 LMPD 4–9 ( × Ar/CO 0.5, 1.0, 2.0, 2.5 29 8,8, 14,14, 16,16, 16,16, 16,16 – 39 – s]
Vertex magnet . Parameters of the LMPD. µ : Front view photograph of the LMPD detector from the location H) [cm] Right Table 3 × W Target 0.55 m × Drift length [cm] Drift velocity [cm/ Drift field [V/cm] Drift voltage [kV] drift gas # of sectors # of padrows # of pads/padrow Absorber thickness [mm] size (L No. of pads/sector Pad size [mm] "Jura−side" "Saleve−side" 0.8 m : schematic top view of the LMPD and the associated beamline. The internal structure of
Left m 0.06 . BPD−3 V1 Beam data were taken with the LMPDprotons surrounding and the thus characterizing target. the This centrality allows of detection the and p+Pb tagging collisions. of grey in order to adjust the dynamiclarge range statistics physics-quality for data the were expected recorded highlystream in ionizing parasitic of particles. mode MTPCs. with After They the optimization allow LMPDtarget a located material. systematic down- During study the of last gray 3 dayswas proton of mounted production the at and 2011 the absorption data nominal taking in position, period and the the with preliminary final proton physics-quality test beams, p+Pb of the data LMPD the were operational recorded parameters. for Then, in 2012 large statistics 158 GeV upstream of the LMPD. Thesurrounding Pb the target target is disc. locatedStandard in The NA61/SHINE the TPC field centre front cage within end strips the electronics thin (copper were used Tedlar strips foil for on readout He capton) (on container top). of tube the LMPD are also visible. Figure 31 LMPD is also shown: thinparticular absorber layers setting reside can between be sensitivelayer layers used or depicted to stopped by inside determine coloured the bands. whether absorber. The a given particle from the target crossed the absorber 2014 JINST 9 P06005 500 6 400 4 Target IN Target OUT Target 2 300 He : energy deposit of particles 0 200 -2 p+Pb collision, overlayed with the Protons c Top right 100 / -4 Vertical coordinate (mm) Vertical 0 3 2 -3 1 -2 -4
Particles stopped in 2nd absorber stopped in 2nd Particles
10
10 10 10 10 10 Entries Energy depositEnergy on the 1st layer (keV) [a.u.] Yield : distribution of reconstructed interaction coordinate for – 40 – 6 Bottom 4 Target IN Target OUT Target 2 0 -2 : event display of the LMPD for a typical 158 GeV -4 Top left Horizontal coordinate (mm) . -6 -3 -4 -5 -6 -2
10 10 10 10 10 Yield [a.u.] Yield In case of the TPC system, the FEE cards [28, ]29 only host pre-amplifiers, shapers, and time- Figure 32 reconstructed clusters and tracks. Greenposition colour of indicates the the reconstructed energy clusters, depositparticle blue (ADC), tracks lines red point depict to points the a indicate straight commontraversing the particle production the tracks vertex first fitted within absorber, to the but the target. stoppedwith clusters. within that the The of second other absorber layer. nuclei The are proton clearly energy seen. deposit along sampling capacitor arrays formanaged 32 by channels, the along readout with Mother ADCs. Boards, The which necessary transmit the command necessary logic clock is signals to steer the data taking with target inserted and removed. The off-target background is small. 8 Data acquisition and detector control8.1 systems Readout electronics and DAQ The readout electronics [42] consists of threethe main TPC parts: FEEs, the the electronics electronics responsible for for readingfor reading out out reading the out FASTBUS the based CAMAC ToF system, based and beam the detectors electronics (see figure 33). 2014 JINST 9 P06005 Central DAQ PC DAQ Central Central DAQ PC DAQ Central PCI-X PCI-X R R C O 4 4 1 1 DDL DDL receivers receivers link bridges link bridges Fiber connectionFiber Fiber connectionFiber CAEN VME – USB USB – VME CAEN CAEN VME – USB USB – VME CAEN
C C B B B B 8 8 8 8 2 2 – 41 – 1 1 Boxes Boxes Concentrator Concentrator LVDS connection LVDS LVDS connection LVDS E C A N E C A N B M E E M M M M 32 32 I I F F C C Readout Readout VME/VSB crate VME/VSB VME/VSB crate VME/VSB 1 Mother Boards Mother 1 Mother Boards Mother . Block diagram of the three main parts of the NA61/SHINE readout system: TPC readout, ToF TOF Beam Fastbus CAMAC 1 1 24 24
The ToF system uses legacy front end electronics based on FASTBUS technology. The readout TPC Front-End TPC TPC Front-End TPC Electronic cards Electronic Electronic cards Electronic of the beam-related detectors (Beam Positionand Detectors, beam TDCs) counter is pattern based units, scalers, onto-VME ADCs traditional bridge, CAMAC makes units. connection to A VMEtively. FASTBUS-to-VME In crates bridge each dedicated of and to these a ToF two and CAMAC- VME CAMAC crates readout, a FIC8234 respec- processor-based controller runs a low level OS9 Figure 33 readout and CAMAC readout of beam detectors. time sampling, ADC conversion andADC value data for transmission each process. timeand slice The of zero FEE each compressed cards TPC on pad. produceof the a These serving Mother are 9 24 pedestal Boards. bit FEE subtracted,SRAM cards, noise The units suppressed were 250 for implemented pedestal Mother using table Boards,Boards, Cyclone storage. which the II Upon time are FPGA an sampling each (EP2C35F672) event withADC capable arrays trigger, subsequent values are which and digitization read is out begins and fanned on processed out ondata the the to stream FEE fly is all by cards, serialized the Mother onto Mother after a Boards which ground-independent withBoxes, LVDS polling. the which connection The can line processed toward receive the data Concentrator fromare 32 Mother implemented Boards. on These Cyclone boxes II actindependence FPGA like for further (EP2C20F484) the serializers long-distance arrays. and transfer, the In DDLpoint order optical to to transfer the line ensure [43, Central galvanic]44 DAQ ground is PC.stream used is from The this triggered data by reaches the theof Central lower the DAQ level first in electronics data push-data headers and mode, attrigger not i.e. the electronics. via the Concentrator the Box data Central level, a DAQ. Busy Upon signal the is issued arrival as a feedback to the 2014 JINST 9 P06005 – 42 – channel on a first-come first-served basis. channel on a first-come first-served basis. (i) The receiver process for the DDL channels. This looks for data on any DDL (ii) The receiver process for the VME channels. This looks for data on any VME odically gets scaler status information from the trigger server. cally gets information from the DCS server. event server upon request.lelization This of starts data the receiving. following two processes for efficient paral- (i) The logger and monitoring/consistency checking process. (ii) The communication unit with the trigger system for summary information. This peri- (iv) The recorder process building the event, writing to disk and forwarding to the above (iii) The communication unit with the DCS system for summary information. This periodi- serving up to 16 monitoring clients. interpreter written using the GNU libreadline library. The readout of the PSD, is designed along the principles of the TPCDue readout, to and acts the similarly push-data mode method, the event data in the different hardware channels arrive at The Central DAQ software runs on a single Central DAQ PC (X7DB8-X motherboard, 64 bit, (i) The core software of the Central DAQ written in C. Its user interface is a command line (ii) The Central DAQ GUI script written in Tcl/Tk language. (iv) The following processes created upon run start: (iii) The event server, created upon Central DAQ start for event monitoring. This is a fork-server to the Mother Boards in the TPC readout system. the Central DAQ software asynchronously. Thein synchronization the is sub-events performed on via the triggereach counters final minute, event-building the level. data Foraddition, pipelines periodic the are checks Busy drained the signal and of dataisolated the each stream TTL trigger hardware is to channel counter RS232 halted register is synchronicity in monitoredstuck is order Busy via to verified. signal a make caused custom sure by In that made a the hardware galvanically event failure. stream is never haltedtotal due 8 to cores of a Intel Xeonport). CPU @ The 2 main GHz, components 8 GB of memory, the 10 software PCI-X and slots, their 4 functions USB are ports, as and follows: a serial based software as low levelinterrupt, DAQ. the As latter are the used processorsby to are the initiate capable experiment’s low of accurate level receiving pre-trigger data signal, external taking.is but confirmed signals The by the as measurement the measurement units main-trigger data are signal areto within triggered only the the FIC8234 read time-out controllers out limit. to if In initiate this thatmemory readout. case unit The an in data interrupt the are is VME transfered passed crate. viaand The the a bridges received trigger data to counter are a stored MM6390 is inthe incremented. a trigger Meanwhile ring counter, buffer the and overwriting the Central older new DAQ data Central events polls are DAQ’s for ring drained the buffer. via incrementation a Feedback of CAEN toCORBO V1718 and register VME-to-USB control units bridge in of to the the the pertinent Busy VME logic crates. is performed via RCB8047 2014 JINST 9 P06005 TCP TCP Monitors Database Database Measurement Access Server Access TCP grabber database RS232 CA – 43 – fiber GPIB CA Server Hardware Caenet Application Measurement . Block diagram of the NA61/SHINE Detector Control System. TCP Control / Monitoring Control Figure 34 The central DAQ software is completed by a system of failure-tolerant scripts with checksum The system monitors parameters of the gas mixture in the TPCs (temperatures, pressure, flow, The block diagram of the DCS is shown in figure 34. Although the system logically consists (i) Gas subsystem, (ii) High Voltage subsystem, (iv) PSD subsystem, (iii) Low Voltage subsystem, the main part of the system isPCs. a single It EPICS-based [45] communicates measurement with server distributed various over hardware a few (CAMAC, VME, PLC, etc.) via various interfaces The GUI and the command line interpreterprocesses communicate of via standard the Unix forked pipes and Cread log program into files. communicate The a via special LinuxPhysmem fast shared is shared mapped memory. memory, by called a The special Physmem, data Linux itself outside kernel gets module the shipped reach with of theand size DDL the verification, libraries. which Linux move the kernel. recorded dataonto after the consistency and tape Quality Assessment system check ofaverage event CASTOR. size was The 2 typical Mbytes. trigger rate in our8.2 experiment was 60 Hz Detector and Control the System The NA61/SHINE Detector Control Systemtrolling (DCS) of is the responsible working for conditions online of the monitoring detectors. and con- water and oxygen content, driftof velocity, amplification, the etc.). high voltage It in also thealso sets sub-detectors: controls and low LMPD, monitors voltage TPCs, parameters power BPDs supplies and of the the front beam end counters. electronics The andof system enables the its following cooling. subsystems: 2014 JINST 9 P06005 – 44 – All measured data is stored in theThere relational are database two (PostgreSQL) GUIs by available. one of One the of EPICS them, which controls the Measurement Server and NA61/SHINE has greatly profited from the long development of the CERN proton and ion This paper describes the facility — the beams and the detector system — as used up to March Upgrades of the facility are continuing and the physics goals are being expanded [4]. Among This paper will be followed by further publications presenting more details on the components clients. It can be accessed only via the Database Access Servermonitors by issuing its ASCII performance, commands. is another one EPICS can client be run and anywhere and canthe is be graphically database. presenting run results only of measurements in retrieved from the experimental area. The 9 Summary and outlook NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) ishadron a production multi-purpose facility in for hadron-proton, the study hadron-nucleusSuper of and Proton nucleus-nucleus Synchrotron. collisions at the CERN sources, the accelerator chain,has as well recently as been the modifiedbeams H2 to for beamline also NA61/SHINE. of serve the Numerous components CERN asits predecessors, of North a in the Area. particular, fragment NA61/SHINE the setup separator last The were one, as latter the inherited needed NA49 from experiment. to produce2013, the the start of Be the CERNcomponents Long Shutdown which I. were Special constructed attention for was NA61/SHINE.tor, paid the These to Forward-ToF wall, are: the the presentation the Low of Projectile Momentum the Particle SpectatorPosition Detector, Detectors, Detec- the the Z- digital and part A-detectors, of the theDetector Beam TPC Control readout and System the and DAQ system, the theand He-beam Trigger the System, pipe. the H2 Moreover beamline the modified upgraded toherited CERN serve from accelerator as the past a chain experiments fragment and separator describedTime are elsewhere Projection are described. Chambers presented The only and components briefly. their in- Thesewalls gas are as the system, well the as two the super-conducting beam magnets, and trigger the counters. ToF-L/R NA61/SHINE upgrades under preparationVertex Detector, are: upgrade of construction the ToF of andextension PSD Forward-TPCs of readout the and systems, gas upgrade of system. of a the ToF Silicon HV system and which were newly constructed for the NA61/SHINE facility. Acknowledgments This work was supported71989), by the the Polish Hungarian Ministry Scientific202 of Research 48 Science Fund 4339, and (grants Higher NN OTKAMPD Education 202 68506 program, (grants 23 and co-financed 667/N-CERN/2010/0, 1837 by NN and the 7150/E-338/M/2013), European the Union Foundation within for the Polish European Science Regional — Development (RS232, Caenet, TCP/IP, GPIB, etc.), performssible all for the the measurements clients and via makespresence the the of results Channel the acces- Access clients protocol. or the The database server availability. runs constantly regardless of the 2014 JINST 9 P06005 , , , ]. . , , CERN-2011-004 , (2012) 035210 (2004) 50. , Chicago U.S.A. (1998). arXiv:1006.1765 hep-ex/0106019 , CERN-90-01 (1990). , C 85 (2011) 034604 , CERN-PS-92-34, in Proceedings A 523 C 84 (2011) 307[ Phys. Rev. all.pdf. , Present performance of the CERN proton B 42 , Berlin Germany (1992). final Phys. Rev. Study of hadron production in hadron-nucleus and , Properties and performance of the prototype Measurement of production properties of positively Measurements of cross sections and charged pion NA61/SHINE plans beyond the approved program Onset of deconfinement in nucleus-nucleus collisions: Nucl. Instrum. Meth. 2nd International Particle Accelerator Conference , – 45 – , CERN-SPSC-2006-034 (2006). The cosmic-ray experiment KASCADE Fifty years of the CERN Proton Synchrotron Acta Phys. Polon. , The JHF-Kamioka neutrino project XIX Linear Accelerator Conference Linac 98 (2003) 490. A 513 ]. ]. Overview of the status and developments on primary ion sources at CERN Concept for a lead-ion accelerating facility at CERN collaboration, J. Abraham et al., collaboration, N. Antoniou et al., The RFQ2 complex: the future injector to CERN Linac 2 UGER UTURE A 3rd European Particle Accelerator Conference , in Proceedings of the IERRE arXiv:1102.0983 arXiv:1112.0150 (2011). Linac [ charged kaons in proton-carbon interactions at[ 31 GeV/c of the spectra in proton-carbon interactions at 31 GeV/c ,CERN-ATS-2011-172 in Proceedings of the San Sebastian Spain, 4–9 Sep 2011, pp. THPS025. nucleus-nucleus collisions at the CERN SPS review for pedestrians and experts CERN-SPSC-2012-022, SPSC-P-330-ADD-6 (2012). Nucl. Instrum. Meth. Memorandum of understanding for collaboration inproduction the in NA61/SHINE hadron-nucleus experiment and for nucleus-nucleus study collisionshttp://na61.web.cern.ch/na61/pages/downloads/mou of at hadron the CERN SPS instrument for the Pierre Auger Observatory [9] NA61/SHINE collaboration, N. Abgrall et al., [8] NA61/SHINE collaboration, N. Abgrall et al., [1] NA49-F [2] M. Gazdzicki, M. Gorenstein and P. Seyboth, [5]P [7] [3] T2K collaboration, Y. Itow et al., [4] NA61/SHINE collaboration, N. Abgrall et al., [6] KASCADE collaboration, T. Antoni et al., [14] H. Haseroth ed., [13] S. Gilardoni and D. Manglunki eds., [12] C.E. Hill, A.M. Lombardi, E. Tanke and M. Vretenar, [10] R. Scrivens et al., [11] M. Weiss, Fund, the National ScienceAgency Centre of of Education of Poland the (grantRNP Ministry 2.2.2.2.1547), UMO-2012/04/M/ST2/00816), of the the Education Russian Federal and Academysearch Science of (grants of Science 08-02-00018, the and 09-02-00664, Russian theCulture, Federation and Russian (grant 12-02-91503-CERN), Sports, Foundation the for Science Ministry Basic18071005, of and Re- Education, 19034011, Technology, Japan, 19740162, 20740160(grants Grant-in-Aid GA and for 1480/2-1, GA 20039012), Scientific 1480/2-2), Bulgarian the Research2010), National Scientific Ministry German (grants Fondation of Research (grant Education DDVU and Foundation 02/19/ tionalfonds Science Foundation of (grant the 200020-117913/1) Republic and of ETH Serbia Research (grant Grant OI171002), TH-01 07-3. Swiss Na- References 2014 JINST 9 P06005 , , , , ˇ Cerenkov , (2014) 2794 . varga.pdf C 74 , A threshold gas Eur. Phys. J. , , GeV/c (1978) 572. , , CERN-DD-78-2, CERN-DD-78-2-REV , CERN-93-01 (1993). Simulation program for particle physics 25 US/. 158 Performance of compensated tile-fiber hadron and Calibration and analysis of the 2007 data Measurement of negatively charged pion spectra in The Cedar (Cherenkov differential counters with 80 Film/en , (2001) 381. Secondary exotic nuclear beams – 46 – 40 , (2000) 237. PVF (2000) 406. The NA49 large acceptance hadron detector 31 , A 461 20 A 453 A 451 (1963) 165. = IEEE Trans. Nucl. Sci. lab , 22 collaboration, Y. Fujii, (1995) 163; (1997) 535. (1999) 210. (1992) 265. (1990) 1230. 45 LHC design report. Vol. I: The LHC main ring. Chapter 21: The LHC as a LHC design report. Vol. III: The LHC injector chain. Part 4: The LHC ion ROUP 37 G Study of the compensated lead hadron calorimeter on hadron, electron and A 385 B 70 A 430 ][CERN-PH-EP-2013-182]. A 4096 cell switched capacitor analog waveform storage integrated circuit The separation techniques for secondary beams CERN heavy-ion facility design report Nucl. Instrum. Meth. , CERN-2004-003-V-1 (2004). Design and performance of TPC readout electronics for the NA49 experiment , The grid-geometry time-of-flight detector used in the NA49 experiment at the , CERN-2004-003-V-3 (2004). Some information on threshold Cherenkovs Nucl. Instrum. Meth. Nucl. Instrum. Meth. , , Study of inclusive and correlated particle production in elementary hadronic interactions Nucl. Instrum. Meth. ¨ , uning et al. eds., ALORIMETER ¨ unzenberg, arXiv:1310.2417 calorimeter [ lead-ion beams CERN SPS experiments, GEANT: user guide and reference(1978). manual Ph.D. Thesis, Budapest Hungary (2003), http://edms.cern.ch/file/900941/1/phd IEEE Trans. Nucl. Sci. Nucl. Instrum. Meth. CERN-SPSC-2008-018, SPSC-SR-033 (2008). inelastic p+p interactions at p lead ion collider injector chain achromatic ring focus) project . http://web.archive.org/web/20070718185118/http://sl.web.cern.ch/SL/eagroup/XCETinfo.html Ann. Rev. Nucl. Part. Sci. Nucl. Instrum. Meth. Nucl. Instrum. Meth. G. M counter [34] G.A. Alekseev et al., [35]JLCC [33] G. Palla et al., [25] Tedlar, http://www2.dupont.com/Tedlar [31] NA61/SHINE collaboration, N. Abgrall et al., [29] F. Bieser et al., [26] Airex foams, . http://www.3acomposites.com/index.php?cmd=39 [27] Carbon fiber Toray, . http://www.toraycfa.com/pdfs/M55JDataSheet.pdf [28] S.A. Kleinfelder, [30] R. Brun, R. Hagelberg, M. Hansroul and J.C. Lassalle, [32] NA61/SHINE collaboration, N. Abgrall et al., [18] C. Bovet, S. Milner, A. Placci and M. Placidi, [16] M. Benedikt et al. eds., [17] O.S. Br [21] H. Geissel, G. Munzenberg and K. Riisager, [22] Cheesecote Mountain CAMAC, Pomona NY U.S.A., [23] . http://www.cmcamac.com/ NA49 collaboration, S. Afanasev et al., [24] D. Varga, [15] D.J. Warner ed., [19] M. Vivargent, G. Von Dardel, R. Mermod, G. Weber and K. Winter, [20] L. Gatignon, 2014 JINST 9 P06005 , , , 10th ]. ]. Three advanced designs of 5th Workshop on Electronics for , in Proceedings of the arXiv:1401.4392 arXiv:1207.2114 , Boston U.S.A. (2004), p. 273. (2014) [ (2013) 99[ Pion emission from the T2K replica target: method, A 701 , in Proceedings of the Low momentum particle detector for the NA61 – 47 – (1994) 326. Test results of a fully projective lead/scintillating fiber Nucl. Instrum. Meth. A A 337 (2006) 70. (1991) 481. Nucl. Instrum. Meth. , A 567 A 308 , submitted to , Snowmass U.S.A. (1999), p. 493. The ALICE data-acquisition read-out receiver card Electron, pion and multiparticle detection with a lead/scintillating-fiber calorimeter The ALICE detector data link Design and performance of the online system for the NA61/SHINE experiment Nucl. Instrum. Meth. , LHC Experiments Workshop on Electronics for LHC and Future Experiments micro-pixel avalanche photodiodes: their present status,Nucl. maximum Instrum. possibilities Meth. and limitations Nucl. Instrum. Meth. calorimeter results and application experiment at CERN in preparation. [45] EPICS, . http://www.aps.anl.gov/epics [44] W. Carena et al., [41] K. Marton, G. Kiss, A. Laszlo and D. Varga, [37] Zecotek, . http://zecotek.com [38] D. Acosta et al., [39] RD1 collaboration, J. Badier et al., [40] NA61/SHINE collaboration, N. Abgrall et al., [43] G. Rubin et al., [36] Z. Sadygov, A. Olshevski, I. Chirikov, I. Zheleznykh and A. Novikov, [42] E. Denes et al.,