2008 JINST 3 S08006 . 1 − s 2 − SISSA cm July 10, 2008 10% due to 30 April 11, 2008 : : ∼ August 14, 2008 : eV. Two LHCf 17 CCEPTED ECEIVED A R http://www.iop.org/EJ/jinst/ UBLISHED UBLISHINGAND P P 140 m from an interaction XPERIMENTS ± E HYSICS 10 days of operation at luminosity P ∼ . After 1 − s NSTITUTEOF 2 I − CCELERATOR AND cm :A 29 -rays with energy from 100 GeV to 7 TeV. This has been γ 10 ∼ UBLISHEDBY OLLIDER P 8.4. Detectors, data acquisition and electronics are optimized to C > η 40 mm, the energy resolution is expected to be better than 6% and the × ADRON H , the light output of the plastic scintillators is expected to degrade by ARGE 1 − : Photon detectors for UV, visible and IR photons; Scintillators, scintillation and s : LHCf is an experiment dedicated to the measurement of neutral particles emitted 2 − 20 mm to 40 mm × cm CERNL 29 2008 IOP Publishing Ltd and SISSA BSTRACT EYWORDS 10 HE c A K T The LHCf Collaboration in the very forward regionthe of hadron LHC interaction collisions. models that The areThis physics used is goal in possible is the to study since provide of the data Extremely laboratory High-Energy for Cosmic-Rays. equivalent calibrating collision energy of LHC is 10

light emission processes; Solid state detectors;identification Calorimeters; methods; Gamma Particle detectors; tracking Particle detectors; Photonphotons; detectors Gamma for detectors; UV, visible Particle detectors; and Radiation IR acquisition damage concepts; to Detector detector control materials; systems; Data Front-endconcepts electronics and for systems; detector Analysis readout; and Trigger statisticalcalibration methods; and Pattern fitting recognition, methods; cluster Simulation finding, methodsfibers and and programs; light Scintillators guides; and Detector scintillating alignment and calibration methods; Overall mechanics design. detectors, consisting of imaging calorimeterssition made sensitive of sensors, tungsten are plates,point plastic installed (IP). scintillator at Although and zero the po- degree lateral20 collision dimensions mm of angle these calorimeters are very compact, ranging from radiation damage. This degradationfrom will a be laser. monitored and corrected for using calibration pulses position resolution better than 0.2 mm for confirmed by test beam results at thein CERN the SPS. These pseudo calorimeters rapidity can range measureoperate particles during emitted the early phase of the LHC commissioning with luminosity below 10 LHCf is expected toweek obtain or data so to of operation compare at with luminosity the major hadron interaction models within a ∼ The LHCf detector at the CERNCollider Large Hadron 2008 JINST 3 S08006 e e b d K. Fukui, J. Velasco, d l K. Masuda, S. Ricciarini, e h D.A. Faus, T. Mase, a h W.C. Turner, k A.L. Perrot, b D. Macina, g A. Tricomi, P. Papini, i g R. D’Alessandro, c S. Torii, – ii – j m Y. Muraki, K. Kasahara, g e G. Castellini, b T. Tamura, Y. Itow, e f M. Mizuishi, and K. Yoshida e M. Bongi, e a K. Taki, g H. Menjo, e M. Haguenauer, L. Bonechi, H. Watanabe b a b Y. Shimizu, e Solar-Terrestrial Environment laboratory, Nagoya University, Nagoya, Japan Ecole-Polytechnique, Paris, France Research Institute for Science and Engineering,CERN, Waseda Geneva, University, Tokyo, Switzerland Japan Konan University, Kobe, Japan Kanagawa University, Yokohama, Japan Università degli Studi di Catania andLBNL, INFN Berkeley, Sezione California, di USA Catania, Catania, Italy Shibaura Institute of Technology, Saitama, Japan Corresponding authors: Daniela Macina (Daniela.Macina@cern.ch) and Yoshitaka Itow) ([email protected] IFAC CNR and INFN Sezione diIFIC, Firenze, Centro Firenze, Mixto Italy CSIC-UVEG, Valencia, Spain A. Viciani, Università degli Studi di Firenze andINFN INFN Sezione Sezione di di Firenze, Firenze, Firenze, Firenze, Italy Italy O. Adriani, M. Grandi, T. Sako, The LHCf Collaboration Y. Matsubara, i j l f e c k g h a b d m 2008 JINST 3 S08006 – iii – mass reconstruction capability 29 0 π 4.2.1 Results4.2.2 for the calorimeters Position4.2.3 resolution of the SciFi Position4.2.4 resolution of the silicon tracker Demonstration of 28 24 27 2.1 Detector6 overview 2.2 Calorimeter6 2.3 SciFi and2.4 MAPMT Silicon strip2.5 detector Manipulator 2.6 Front counters 3.1 Global flow3.2 of trigger and DAQ Electronics and3.3 DAQ for the SciFi Electronics detector and DAQ for the silicon tracking detector . 4.1 Expected performance4.2 of the LHCf detectors Results of SPS beam tests 4.3 Results of radiation damage tests 18 10 17 11 16 19 14 14 24 31 1.1 Physics of1.2 the LHCf1 experiment Experimental3 overview 2 The detectors6 3 Trigger and DAQ electronics 4 Performance of the LHCf detectors 5 Summary Bibliography 16 19 33 35 Contents The LHCf Collaboration 11 Introduction ii 2008 JINST 3 S08006 eV) has great scientific interest 19 eV and the GZK cut-off might not 20 bursts [2] and so on. However another result 0 – 1 – eV [6]. 19 10 × Ten years have passed since the air shower experiment AGASA reported that the cosmic Measurement of the chemical composition of the highest energy cosmic rays can also give 1.1 Physics of the LHCfResearch experiment on the highest energy cosmic-rays (energy above 10 Introduction since their origin, propagation and interactionsphysics. are unknown To and give may an yield idea informationwith of about the new the spectrum type and of composition informationLHCf of available experiment can the we make briefly highest a summarize energy contribution the cosmic to situations this rays field. and then describeray how spectrum the at the highest energy may extend beyond 10 obtained by the HiRes experimentAGASA was experiment consistent used with the a existenceployed large of a array the novel of calorimetric GZK technique cut-off surface utilizing [3].new detectors observation results of The whereas have been atmospheric the published fluorescence. by HiRes Recently theence experiment ICRC07 Auger [4]. collaboration em- at Auger the employs a internationaltelescopes combination cosmic-ray of and confer- surface the detectors new and results atmospheric support fluorescence experiments the are existence shown of in the GZK figure 45% cut-off.1.1 . then The their results If results of the would these be energy three in scale agreement of with the the others. AGASAimportant results information were about where reduced they by are produced.duction Several of astronomical the candidates for highest the energy pro- energy cosmic obtained rays depends have on been the composition discussed totravel in be through the accelerated. nearby literature The inter-galactic highest and energy space the cosmic-rays almostreported maximum can without that deviation the by arrival direction magnetic of fields.active the galactic Auger highest nuclei has energy (AGN) [5]. events is This correlated naturallyHowever composition suggests with that measurements the the reported distribution primaries by of are Auger mostmixture indicate likely of that protons. protons the and primary heavy composition nucleistatistics is (Fe) for a up composition to analysis the - highest 4 energy where they so far have sufficient Chapter 1 exist [1]. Ifexplanation this like were the true, decay the of origin cosmic of strings or the Z highest energy cosmic-rays would need an exotic 2008 JINST 3 S08006 eV. LHCf is an 17 . In this paper, an 1 eV. − 17 s 2 − eV which is 6 orders of 20 cm S or Tevatron. The perturba- 30 ¯ p p AGASA HiRes mono Auger’07

– 2 – log (Energy [eV]) S have been available for calibration of the forward neutral pion pro- 18.5 19 19.5 20 ¯

p

eV [9]. The 14 TeV center of momentum energy of the Large Hadron p

−32 −34 −36

/eV]) log (Flux [/sr/sec/m (Flux log 14 2 : Energy spectra of primary cosmic-rays obtained by three large experiments. The red, If it turns out that the highest energy primaries have significant Fe composition thenIt the is well known that understanding the results of cosmic ray experiments depends strongly There are two key quantities at the primary interaction vertices which determine the devel- Figure 1.1 blue and black points represent the result of AGASA, HiRes and Auger, respectively. “GZK-cut off”-like feature couldcrowave background perhaps (CMB) be photons. interpretedstanding of Further as all investigations measurements. photo-dissociation are needed by for cosmic a mi- consistenton under- the use of Montehave Carlo not codes. been verified However experimentally the near hadronic the interaction GZK models energy used region in 10 these codes Collider (LHC) will push the laboratory equivalent collision energy up to 10 duction spectrum at 10 opment of air showers; theat total very inelastic forward cross section angles. andemployed the The by particle the former production TOTEM will [7] energy be or spectra ward ATLAS measured production collaborations at [8]. spectra in LHC Therefore LHC a with is new roman strongly measurement pot desired on for- to detectors calibrate such the as models at 10 magnitude higher than the laboratorytive QCD equivalent models energy used of for the simulationmodels of S calibrated air with shower experimental experiments data are whereexperiment essentially they taken phenomenological are at available. the So S far only data from the UA7 experiment to perform a measurementspectra of of neutral the pions very and forward neutrons.phase Measurement production of will cross the be sections done LHC in and commissioning a energy before short the period during luminosity the reaches early 10 overview of the LHCf instrumentation iselsewhere given. [10]. Previous After study providing of an the outlinedetectors of prototype and the detectors the LHCf is data experiment found in acquisition section systemIn1.2 , will section4, the be simulation details described studies of in of the section2 the expectedandresults performance section3, from during respectively. beam the tests LHC performed operation in and 2007 the at first the CERN SPS are reported. 2008 JINST 3 S08006 × w – 3 – 100 mm square there is an instrumentation slot of 96 mm × extending from 67 mm below the beam height to the top of the TAN. The l 1000 mm : Geometry of the IP1 area of LHC. The structure seen in the center represents the 100 mm square centered on the zero degree crossing angle beamline. In the crotch of this × h × The LHCf detectors are two independent shower calorimeters inserted in the TAN instrumen- 140 m from interaction points (IP) 1 and 5 in order to protect the outer superconducting beam 607 mm aperture for the LHCf measurements isof limited the by the beam width pipe of in theprojected the slot to and D1 the by dipole detector the projected plane vertical to andThis aperture unique the of location the TAN. covers The instrumentation the cross slot pseudo-rapidity of sections range the of from TAN the 8.4 are to D1 drawn infinity. beam intation pipe figure slots1.4. on both sides ofthe instrumentation IP1. slots Each followed by occupies BRAN a luminosity 300the monitors mm 100 ATLAS mm length ZDCs in in [11]. length the12] [ Both and mostcalorimeters the finally upstream LHCf made position detectors of of consist plastic of scintillatorslayers a interleaved are pair inserted with of in tungsten small order sampling converters. touse and provide Position different imaging incident sensitive shower techniques positions. and The geometry two for detectors the are similar, purposes but of redundancy and consistency checks of Figure 1.2 ATLAS detector surrounding the interaction point.indicates the The straight long line straight from sectionplaces top-left of marked to ’TAN’ the at bottom-right LHC both sides tunnel of and IP1. the LHCf detectors are1.2 installed at the Experimental overview The LHC has massive± zero degree neutralseparation absorbers dipoles (D2) (Target from Neutral neutralparticles Absorber; particle from debris TAN) the from located IP the areTAN. IP swept Inside (figure aside TAN,1.2 the by beam figure the vacuum1.3). innerbeam chamber beam tube makes Charged separation a facing dipole Y the D1 shaped IPhas before transition to reaching from been two the a carefully separate single machined common beam100 to tubes mm joining have to a the uniform“Y-chamber”, arcs just one behind of the radiation 100 LHC. mm length The projected Y-chamber thickness over a 2008 JINST 3 S08006 protons per 10 -ray energy spectrum that can be measured. γ T -ray incident position and recon- γ -rays, measure the γ – 4 – coverage without scanning and/or employing a finite crossing . Owing to the limitations imposed by radiation and the configu- 1 T − s 2 − cm 30 -ray pair invariant mass distribution that shows a clear peak at the neutral pion mass. : Photo of the TAN absorber located 140 m from the IP. Left: TAN fully assembled in γ range would be further increased by operation with a non-zero beam crossing angle of T rad, because the center of neutral particle flux moves downward. The geometry of detector 2 LHCf is not designed to be a radiation hard detector and so will be removed when the LHC With these detectors we will be able to identify Both detectors are supported by manipulators mounted to the top surface of the TAN in order µ 100 GeV) with a few per cent energy resolution, measure the > ration of the DAQ, data taking of LHCf is planed for the 43 bunch operation and 10 ( struct the Hadron showers of highdecreased energy energy resolution neutrons of at about 30%. zero degrees can beluminosity also exceeds measured, 10 however, with angle. In front of each detector,provide a useful Front trigger Counter information (FC) by made of covering plastic a scintillators larger is aperture inserted. than the They calorimeters. Figure 1.3 is designed to maximize the P the LHC tunnel seen fromfacing the the IP. IP The 96 side. mm gap Right: between the TAN two during beam pipes assembly allows at space for CERN installationthe seen of measurements. from detectors. In the addition, top coincidence betweenbackground these due detectors to may beam-gas be interactions useful andters for for are rejection application designed of to to diffractive have physics. energyWith and The such position calorime- properties, resolutions better the than experimentmodels 5% used will and in 0.2 be cosmic-ray mm, studies, able respectively. or toin to LSS1L discriminate construct new (Arm between 1; models. the In IP8 this majorIP2 side) paper, side) interaction is the is referred detector referred installed as as detectoron 1 detector the 2. and left the Standing and detector detector inside 2 installed the is in LHC on LSS1R the ring right. (Arm and 2; lookingto at have IP1, the detector capability 1 of is remotelyshows the moving geometrical the configuration detectors of each vertically detector byof viewed a from the IP1. 120 smaller mm In calorimeters stroke. default is setting, Figure the the placed center 1.4 detectors on vertically the from horizontal their midplane. defaultThe positions Using increases P the the manipulators range of to P move 140 2008 JINST 3 S08006 position TAN slot internal walls TAN projection at the of the dipole region elliptical vacuum pipe 96 211.8 calorimeter towers

) will occupy the region in front of the BRAN.

40 l 20

– 5 – 5 99 mm × h beam center 605 mm

R47.8 ×

w 87.7 ) a few minutes of data taking can provide enough statistics to discrimi- 1 − s 2 − cm 29 : Cross sections of detector 1 (top) and detector 2 (bottom). Grey squares indicate the The purpose of the Cu barsshielding is for to the generate downstream showers D2 for magnets. detectionsame The by length LHCf the in calorimeters BRAN and as nuclear the well interaction Cu aswith lengths bars to LHCf so have provide and the nearly with the BRAN the signals Cu will bars. be very similar for operation nate between hadron interaction models.LHCf After detector a will week be or removed sothree from of Cu TAN operation bars during it (each a is 94 brief mm anticipated machine that stop. the In the absence of LHCf Figure 1.4 calorimeters in the detectors whileVertical and a elliptical green blue square lines shows indicatethe the the beam physical coverage pipe, aperture of respectively. limited the by the silicon walls strip of sensor. the TAN and bunch which are foreseen at theluminosity very (10 beginning of LHC commissioning. At this low intensity and 2008 JINST 3 S08006 aluminum box for each detector as l for detector 2. The first two pairs are 0 280 mm × h – 6 – 620 mm × w for detector 1 and 6, 12, 30 and 42 X 0 , respectively. Most of the tungsten layers are attached to holders made of G10 λ and 1.7 Calorimeter components (scintillator, tungsten and PMT), position sensors and their front- 0 2.1 Detector overview Both LHCf detectorscalorimeters employ is two similar imaging (exceptquite for shower their different. calorimeters. sizes and Detector 1while orientation), While uses detector the 2 scintillating the uses position silicon fibers sensitive structure strip6, sensors (SciFi) sensors. 10, of are and 30 Four the Multi-anode and X-Y 42 PMTs pairs X of (MAPMTs), the position sensors are installed at The detectors Chapter 2 optimized to detect the showerfor hadronic maximum showers of developed deep gamma-ray in inducedessary the showers calorimeters. not only These and position to the sensitive obtain other sensorsthe the are two effect transverse nec- are of momentum leakage of the fromwith incident the respect primary edges to but the of total also the energy tocan calorimeters. is correct only correct for a Because for function the this of fraction effect thecorrection by of position are and measuring shower found independent the leakage elsewhere of position [10]. the of energy, we the shower. Details of theend shower electronics leakage are packed in a 92 mm shown in figure 2.1, 2.2, 2.3 .One The size wall is of designed the to box fitfront-end the for circuitry narrow detector instrumentation for 2 slot the is in silicon the made strips.by TAN. of The the copper detectors manipulators. to in their better In boxes dissipate frontscintillators are the called of attached the heat each to Front generated detector and Counter by supported (facing (FC) the the is IP), installed. a counter composed of thin2.2 plastic Calorimeter The longitudinal (along the beam direction) structurecalorimeter of the consists calorimeter of is 16 shown layers in of figure (Eljen2.4. tungsten Technology plates EJ-260) Each for interleaved measuring with the 3 deposited mm energy.is thick The 7 plastic thickness mm scintillators of for the the tungsten first plates 11is layers 220 and mm. 14 mm In for units the44 of rest. radiation X Including the and position hadron sensors interaction the lengths total length the total length of a calorimeter is 2008 JINST 3 S08006 Sr 90 20 mm × 4 mm grid with a × 32 mm for detector 2. The cross 10%, and is corrected in further × ± 25 mm and 32 mm – 7 – × impedance (C-50-3-1) has a delay of 4.23 ns/m and attenuates the : Photo of detector 1 (left) and detector 2 (right). Ω Figure 2.1 40 mm for detector 1 and 25 mm × Each plastic scintillator is viewed by an acrylic light guide and then read out by a PMT The coaxial cable of 50 -ray source through a 2 mm diameter collimator. An example of the measured non-uniformity while the holders near the siliconpinned layers in are made position of with Delrin. two G10 All the rods. layers The are transverse stacked sizes together of and the calorimeters are 20 mm and 40 mm sections of two detectors are shown(9 mm), in electro-magnetic figure showers1.4 . are Because well ofthe contained incident the even position for small provided such Moliere by small radius the calorimeters. of position In sensitive tungsten layers addition is used to correct(HAMAMATSU for R7400U) shower-leakage. through 1 mm diameteramplified optical by fibers. pre-amplifiers installed The on signals thethe from top counting the of PMTs room the are TAN (USA15) (amplification through factorscintillation 200 = light m is 4.8) coaxial not and collected cables. sent uniformly to of over Because the light of area yield of the a has light scintillator. been guidesembly. The measured position geometry, for dependence The each light scintillator yield light-guideβ from combination the before scintillators detector as- wasof measured light on yield is a shown 4 inmuons mm in figure a2.5 . test beam The at correction theanalysis of SPS. as this Typical described non-uniformity non-uniformity in is was section about also4.2.1. checked with pulse height from the amplifierslinearity by over a a factor wide of dynamic range, 5chosen. the but combination The transfers of scintillator 90% scintillator has of andAlso a the PMT the total long have bias been charge. decay resistor carefully time To network (9.4wide obtain of nsec) dynamic the to range. PMT reduce was the optimized peak to current assure in a the good PMT. linear response over a

2008 JINST 3 S08006 PMT H7400 PMT

20mm tower 32 x 110 x 32

40mm tower MAPMT FEC MAPMT MAPMT – 8 –

90 608 : Front cut-away view of detector 1 showing the structure of the calorimeters, flexible These linearity curves have been measured for all PMT’s for various values of bias HV. At The linearity of the system is measured using a fast nitrogen laser (USHO KEN-1020; emis- Figure 2.2 sion wavelength at 337 nm).the Because scintillator the with nitrogen a laser 0.3as directly nsec excites that pulse, the excited the wavelength by shifter time awith in profile charged different particle. of bias HV. the The Figure scintillation modified2.6 a PMT lightshows single shows the is good minimum typical nearly ionizing linearity particle linearity with the (MIP) a of same can typical the be HV PMT detected of response with 400 V about while typical 1000 V operating HV. HV, the linearity was checked for all the PMT’s by changing the intensity of the light guide fibers, PMTs, MAPMTs front-endenlarged view circuit of box the and left inner one. cabling. The right figure is an 2008 JINST 3 S08006 5 -ray. γ – 9 –

90 608 : Front cut-away view of detector 2 showing the structure of the calorimeters, flexible In order to monitor and correct for time variation of gain or radiation damage to the scintilla- tors, a fast nitrogen laser willthrough 200 be m installed bundles in of USA15 quartz fibers. forwill be periodically Pulse monitored illuminating to during pulse each the variation scintillator of run laser by intensity two is dedicated about PMTs 20% at and USA15. Figure 2.3 MIPs expected at the shower maximum of a 10 TeV light guide fibers, PMTs, silicon layers,figure their is an front-end enlarged circuit view boards of and the inner left cabling. one. The right fast nitrogen laser preciselyexample with of a the linearity variety of of theintensity neutral PMT in response. density Here units (ND) the of filters. horizontalvertical axis the axis indicates Figure equivalent the is number2.7 nitrogen the laser ofshows output(<5% an shower of deviation) for particles the incident (MIPs) PMT. light Thus intensity detected varying all at from the that a corresponding PMTs to layer. were 1 MIP checked The up to to assure the 10 good linearity 2008 JINST 3 S08006 Scintillator Tungsten Silicon Scintillator Tungsten SciFi – 10 – Longitudinal size (mm) Longitudinal size (mm) -rays. β

Detector#2 Detector#1 0 50 100 150 200 0 50 100 150 200

25, 32 mm 32 25, 20, 40 mm 40 20, : Longitudinal structure of detector 1 (top) and detector 2 (bottom); grey, light blue, : Position dependence of the light yield in a plastic scintillator. Color scale indicates

5 0 5 0 Vertical size Vertical Vertical size Vertical -5 -5 45 40 35 30 25 20 15 10 45 40 35 30 25 20 15 10 Figure 2.5 relative signal intensity generated by 2.3 SciFi and MAPMT The position sensor of detector38). 1 is A composed SciFi of belt 4 consists X-Y of pairs 20 of (40) SciFi’s SciFi in belts a (KURARAY SCSF- single hodoscope plane for the 20 mm (40 mm) Figure 2.4 orange and red indicate therespectively. layers of tungsten, plastic scintillator, SciFi and silicon strip sensor, 2008 JINST 3 S08006 m thick µ ˙ mm calorimeters 64 mm total surface area, which × m pitch is implanted on the junction side. µ – 11 – : Linearity of scintillator and PMT excited by a nitrogen laser. Horizontal axis is the Figure 2.6 incident laser intensity in units of equivalent(1 MIPs AD and count vertical corresponds axis to is 0.025 AD pC). count Results of are the given PMT for output PMT HVcalorimeter. bias from Each 375V to SciFi 1100V. hasacrylic 1 water mm paint square to improve cross-section. lightto collection fix The efficiency, the to SciFi’s SciFi in reduce a belts cross plane. talka are Because between SciFi fixing painted SciFi’s, belt the and with are SciFi’s with covered white paint with is kapton not tape. very strong, Hodoscope both planes surfaces of of the 20 mm and 40 that are inserted in thewith same the layer are scintillator glued and on480. tungsten the acrylic layers Each frame with SciFi (figure G102.8) is1 mm rods. and connected pinned diameter. channel together The by The total(HAMAMATSU channel clear number H7546). with fiber of optical is The SciFi cement attached SciFi channelsphoto to as photon electrons. is a a yield We clear need light of round 8 guidechannels a fiber MAPMTs of to single to of the read one MIP 8 out MAPMTs of corresponds 480 (512) 64 to exceeds channels that of anodes more of SciFi’s, of than the so SciFi’s. a 5 the total MAPMT number2.4 of Silicon strip detector The position sensor ofplane detector consists 2 of is 2 single-sided composedbarrel sensors, of identical part 4 to of those planes the used oftwo Semi-Conductor by orthogonal the Tracker microstrip coordinates. ATLAS (SCT) silicon experiment These [13] for sensors. silicon , the is sensors enough which have Each to 64 are cover mm used the entiren-type for cross wafer. the A section sequence measurement of of the of 768 calorimeter, p+The and microstrips PACE3 chip, with are a 80 produced 32 ch on device a designed to 285 work with the LHC 40 MHz clock and produced for the 2008 JINST 3 S08006 m. -ray µ γ 5 5 10 10 4 4 Number of particles Number of particles 10 10 – 12 – 3 3 10 10 3 4

98 96 94 92 90

110 102 100 10 108 106 104 10 Deviation from linear fit linear from Deviation ADC counts(0.025pc/count) ADC : Linearity and dynamic range for one of the PMTs at nominal HV. The filled circles In this way we havetwo a printed total circuit of boards). 384also channels The used for silicon to sensor each provide is silicon bias glued sensorMicrostrips to on (12 the on a PACE3 sensor the chips, thin through housed silicon fiberglass its on sensorsof fan-out backplane circuit have INFN-Florence. by been that means The is of wire-bonded front-end a toin electronics conducting the turn glue are fan-out are [15]. glued lines wire-bonded to in totracking dedicated the the layer kapton clean is boards fan-out then room and circuits, glued to that on the a fiberglass 0.5 mm circuit, thick as aluminum shown layer in (used figure for mechanical2.9. support) and Each shower maximum is indicated by an arrow. CMS Silicon Preshower Detector [14], has beenadjusted chosen working for point, the front-end the read-out. chipsdeviation With a from have properly a linearity of high 6%). dynamicradius range in Due (up tungsten, to to we the 600 decided limited MIPs to space with read inside a out the maximum every TAN and other the strip; small the Moliere read-out pitch is hence 160 Figure 2.7 show the result of theSPS. laser Horizontal calibration axis while shows the relativeof open intensity MIPs circles of determined show from the the the laser result beam light of test. in the The units beam mean of test number the of at equivalent shower number particles at the 7 TeV 2008 JINST 3 S08006 – 13 – : Photograph of a silicon layer during the assembly phase. Figure 2.9 : Photo of the SciFi hodoscope glued on the acrylic frame. Left and right parts are single covered by a blackcircuitry Delrin part. frame This metal on frame the isend also silicon used circuits to and dissipate extract by the approximately heat 60 athick produced W copper by 8.5 in mm wall the chips total) used thick (silicon in by front- aluminum the means detector frame of package on of a detector the good 2. thermal contact with the hodoscope planes of 40 mm and 20 mm calorimeters, respectively. Figure 2.8 2008 JINST 3 S08006 ) and calculating 2 and R 1 m. When the motor is driven with 15 V DC µ – 14 – 2.0 mm; Saint-Gobain Crystals BC404) are aligned in × 80 mm m. This same result was obtained several times at intervals of × µ measured at the same time for various positions. The rms deviation of the pot P , one can obtain a good position resolution. The use of a resistance ratio compensates 2 R 1 + R 1 R The absolute position of the detector is measured by two methods. One is to use a linear = coverage as well as to retract the detectors from the beam line to avoid unnecessary radiation T pot for the possible effect of temperatureencoder change. value To determine and the resolution we compared the optical the vertical and horizontal directionsBetween to the compose two a layers, double aare layer copper plate counter sent of as through 0.5 shown an mm in acrylic thickness10) figure is light placed2.10. inserted. guide outside and Scintillation of light opticalroom the outputs fibers and TAN to recorded instrumentation four by slot. PMTs ADCs.additional (HAMAMATSU The H3164- trigger The signals information. PMT are The signals also FCin sent are can both to sent Arms be discriminators with to used and as to the may widebeam-gas tag be counting an interactions IP acceptance used and interactions as for with beam-halo possible an for particles interactionsFC reducing produced with can background the events also beam produced be by pipe usedby upstream in the of anti-coincidence the calorimeters mode TAN. and to The interactions. not ensure charged that Using particle neutral the background particles segmentedmeasurement structure are produced of of being by incident the detected particles. beam-gas FC, and we beam-halo also expect a certain level of position nominal voltage, the detector movessends with out a two speed sequences of of pulsesreceives 10 these mm/min. with pulses different and During phases. gives the movement A position of the counterknown the to encoder installed detector. be in However, generally, susceptible the optical encoders to counting are radiation room a damage. backup. Consequently a The potentiometer potentiometer has (Mutohpoint been RECTI moving prepared with P12) for the is detector. simply By a measuring variable two variable resistance resistances with (R the sliding residual from a linear fitone was week. 70 2.6 Front counters The FCs have a thickness ofof 8 thin mm plastic and scintillators are (40 mm inserted in front of detector 1 and detector 2. Two pairs 2.5 Manipulator The manipulators move theP detectors in the verticaldamage when direction data in is not order beinglimited taken. to access The increase to manipulators the can the TAN be area range operated andto remotely. of its be Considering high as the radiation robust environment, as the possible manipulatorsdriven by to were DC avoid designed power any supplied mechanical from trouble thepolarity during control of LHC room. operation. the The movement power A direction supply DC isare motor that determined installed is by is at the also the top switched and in bottom the to control limit room. the stroke. Twooptical mechanical encoder (Mutoh switches DS-25) with a precision of 25 P 2008 JINST 3 S08006 – 15 – : A schematic view of a front counter (FC). Two pairs of plastic scintillators segmented Figure 2.10 in vertical and horizontal directions are indicatedthickness by is light blue inserted rectangles. between the A copper pairs. platelight The of guide scintillator 0.5 and mm light optical outputs fibers. are fed to PMTs via an acrylic 2008 JINST 3 S08006 Data sent to USA15

Digitize Sample&Digitize

at TAN at TRG to MAPMT&silicon to TRG – 16 – PMT Signal PMT Discri Shower LEVEL2 TRG ADC Clear ADC Gate Time after collision (nsec) : The timing chart for trigger and DAQ. Figure 3.1 (4800ns depth analog memory) event L2 ¡ƒ L1 PMT Signal silicon Signal MAPMT Signal BPTX Discri 1,2 BPTX1,2 BPTX Coinci. LEVEL1 TRG 0 500 1000 1500 2000 2500 Signal in USA15 collision 3.1 Global flow of triggerData and acquisition DAQ is carriedoptimized out for in 43 bunch the operation.figure ATLAS counting3.1. A room timing Signals diagram (USA15). fromcables. of the trigger A All detectors first and the level data reach trigger sequences acquisition theusing is is two are electronics generated BPTX shown when in signals in a the generated bunch byfrom counting crossing two (BX) the room Beam occurs interaction though Position that point. Monitors 200 can m (BPMs)for be At installed the identified every plastic 175 m first scintillators away (CAEN level V965). trigger,detectors The is a particle 466 500 flight nsec nsec time and gate from the theThe signal signal interaction propagation is signals point time sent to between from our the to plastic detector the(CAEN and scintillators ADC V814B) USA15 arriving is by at 860 custom nsec. USA15 maderespectively. are NIM The split FANOUT outputs modules into of with ADCs the amplification discriminators and factors are discriminators of sent 1 to and VME 4, FPGA boards (GND GPIO GN- Trigger and DAQ electronics Chapter 3 2008 JINST 3 S08006 sec after the first µ sec during LHCf operation, we can easily µ – 17 – events from both arms. Two other PCs, one for each arm, also 8 The data acquisition is carried out independently for the two arms. However in case of a high The data acquisition is carried out using the MIDAS package (Maximum Integration Data In order to synchronize with ATLAS events in possible further analysis, we count the number level trigger, the ADC isread cleared. data, a At final the signal to secondtrigger collect level is all trigger, sent the if data to is the the issued.For acquisition FECs the For PC to silicon the is sample SciFi tracker and enabled in in detector digitize detector to digitized 1, 2, the as the the MAPMT described second signal in signal level stored section as in3.3.and described the recorded analog Then in together memory digitized section with at pulse. 3.2 the the height calorimeter proper data data. timing is is sent to the countingbackground room counting rate, which can bethan expected expected, if we the can residual use gasFC a with in coincidence large the between acceptance beam the coverage pipe are two isthe expected arms far to opposite to supply worse side. suppress coincidence signals this with background. the detector The on Acquisition System, [16]). Onedetector MIDAS 2. server The PC raw controls data sizes two ofDAS front a format. single end The event MIDAS PCs for server two for PC arms detectorof also are 1 performs data, 1.2 and a kbytes corresponding and RAID1 to 14 storage about kbytes and 10 incommunicate can the with store MI- the up MIDAS to server 1.5 for Tbytes aconverted to fast the analysis ROOT during format the by which run.analysis fast The on-line tools MIDAS analysis format [17]. will can be Some be made basic withdistributed results the in standard of the ROOT the CERN fast network every analysiscontrol second (counting data through rate, (electronics the event temperature, Data position, HV, Interchange LV etc.) Protocol values,Some (DIP). manipulator important are Slow machine position, conditions etc) (luminosity, are crossing also angle,DIP etc.) recorded. and are recorded also in received our through data the base. of the ATLAS level-1 (L1A) triggers and 40are MHz reset clock (Bunch roughly Clock every or second BC)ATLAS. counts. These by counts These the are counts latched Event and Counter stored in ResetLHCf FIFO trigger (ECR) when is a signal L1A generated. that signal Time arrives is synchronization andwith readout of also one when the issued a second acquisition from PC accuracy with can theof enable CERN the us time PC server clock to and correlate the LHCfBecause BC the and count interval gives ATLAS between the events. bunch absolute crossings The time willidentify of combination be the each 2 correlated event with events. a These precision methodsdetector of will 1 25 also and nsec. be detector 2. used to identify the coincident events of 3.2 Electronics and DAQ forThe the MAPMT SciFi signals detector are readwhich out analog with ASICs the Front (VA32HDR14),chips, End ADCs each Circuits of and (FECs) which sequencers contains packed 32 in are sets the of mounted. detector preamplifier, on shaping amplifier, Two sample VA32HDR14 and hold circuits, 0324-3). Then the second levelthan trigger 300 is particles issued corresponding when tologic more the and than energy energy 3 threshold threshold successive will of layers be abouttime detect further 100 of more optimized GeV. Details considering LHC of the operation. actual the beam trigger If conditions the at the second level trigger is not generated within 1 2008 JINST 3 S08006 s after the shower matches with the peaking time of – 18 – µ s. The digital data are transferred in a serial line from the µ s. The peak voltages recorded by the sample and hold circuits µ The analog preamplifier (PACE3) outputs are digitized by custom made ADC boards with 12 and one analog multiplexer, areof used the to shaping read out amplifier theare is 64 read 1.9 out channels through for an onedigital analog MAPMT. conversion multiplexer. Peaking of time One 32 channels ADC in coupleddetector 64 to via one LVDS VA32HDR14 to performs an the interfaceare board carried installed out on when the ain VME trigger section bus. signal3.1. arrives The The at trigger processes the signal afterthe arriving FEC shaping sampling 1.9 according amplifier. to the level-2 trigger described 3.3 Electronics and DAQ forThe the DAQ silicon used tracking for detector thefor silicon . the part large of LHC detector 2 experiments, inserted isthe in LHCf mainly custom requirements. based made on boards the and fast produced electronics taking developed into account bit resolution. These boardsof are the mounted, optical piggy-back, link on communicationsPACE3 a and chips. clock, mother Two level-2 board silicon trigger which detectorsof and also are 4 slow serviced takes control mother by care distribution boards one to areformation, mother the installed board are in in sent the such via TAN a optical area.room. way fiber The that The links receiver a digitized to board total data, a formatsto the along VME digest. data with receiver The in board other PACE3 an chips in status appropriate receive the in- system the way Atlas LHC developed for 40 at USA15 the MHz CERN common counting clock detector for and 2(FEC) LHC level-2 DAQ module [18]. trigger through (developed The the for signals TTCrx themands are needed CMS coded to experiment through properly set a]) [19 the Front which PACE3are internal End also sent registers. Controller through takes From the optical care FEC links of these downdecodes fast the the to control signals the I2C signals and experiment com- sends in them the viaules(CCUM) tunnel. an on electrical A the token custom ring mother to receiver boards. the boardboth Clock clock, then and These trigger Control and CCUM Unit I2C Mod- [19], commands developed for for the PACE3 the chips. CMS tracker, decode 2008 JINST 3 S08006 ) 0 X ) with com- λ -ray energy is γ -rays. γ and 1.7 0 X -rays. Selecting events with γ -ray energy. Here the γ ˙ mm calorimeter after shower leakage cor- 20 × – 19 – ), the detector still can be used as a hadron shower calorimeter. To minimize longitudinal The number of shower particles contained in calorimeter is plotted in figure 4.1 as a function The expected energy resolution of the 20 mm While the total length of the calorimeters expressed in nuclear interaction lengths is small λ 4.1 Expected performance of theHere LHCf we detectors present the resultsdetectors described of in Monte section2. Carlo Detector studieslater performance in for was section evaluating also 4.2 the checked In performance bywas these beam of studies, used tests the EPICS for described LHCf [20], detector whichwhich simulation. is have widely been used EPICS well in simulates benchmarked airprimary by all shower hadronic results experiments, interaction electromagnetic from model and used EGS4 in hadronic orused this CERN in processes section test air is shower DPMJET3 beam simulations. [21] experiments. which is The also commonly Energy resolution The LHCf detectors consist of tungsten sampling shower calorimeters (44 Performance of the LHCf detectors pact apertures which results in shower particle leakage from the edges ofof the the distance calorimeters. between the showernegligible, center we and the have nearest found edge. thatUsing Though it the the does leakage fraction not shower is depend position not function on measured in the figure by energy4.1, of the the measured the position shower incident energy sensitive primary can layers be particle. corrected together forrection with shower is leakage. the plotted leakage inreconstructed figure from4.2 theas energy a deposited by function shower of particles incident after the 3rd tungsten layer (at 6 Chapter 4 shower leakage, events aredetector. selected Selecting which events start for their whichrequiring shower the that the shower development energy axis near deposited is the in 2 the mm front first or of radiation more length the from exceeds that the deposited closest by edge, 20 and MIPs, (1.7 in order to prevent contaminationshower due axis to 2 background mm of or low morerection, energy from the the expected nearest energy edge resolution is of 6.3% the for calorimeter 100 and GeV applying and the 2.8% leakage for 1 cor- TeV 2008 JINST 3 S08006 20 mm × as a function of 0 -rays. The effect of γ -rays for the 20 mm γ m for 1 TeV µ – 20 – : Example of the shower leakage function for 2 TeV calorimeter. The upperdistance plot of shows the the incident number positionter from of correction by the shower the nearest particles leakage edge.shower after function. positions The 6 are The X 2 lower blue mm plot arrow or shows more shows the from the the fiducial same nearest area data edge. where af- thethen incident a 30% energy resolution ising expected the for cuts 6 discussed TeV neutrons. above is The about detection 4%. efficiency after apply- Position determination The simulated position resolutionincident of shower the position SciFi is estimated layersweighted from for the by detector fiber 1 their with is ADC the shown100 peak counts. GeV in signal to and figure 7 The TeV the4.3. though adjacent resolution itthe 2 is worsens The silicon fibers at better layers higher of than energy detector due 0.2 2saturation mm to was is saturation. over almost also The negligible simulated the position at and energy resolution this it of energy. range is of 15 Figure 4.1 2008 JINST 3 S08006 140 m ± decays, neutrons or neutral 0 π -ray events. Here the acceptance is γ Energy (GeV) Energy (GeV) -rays from γ 3 3 10 10 -ray energy determination. The upper plot shows γ – 21 – and after the shower leakage correction. The lower plot 0 2 2 10 10 5 4 1

10

10 10 Energy resolution (%) resolution Energy Number of particles of Number : The linearity and resolution in the Figure 4.4 shows the geometrical acceptances for single drawn as a function ofpoint the of distance between a the particle center on of LHCf. the neutral particle Without flux beam and crossing the angle, impact detector 1 will locate the center of kaons reach the detector. In the casea of few 7 + cm 7 around TeV collisions, the theirof center flux the is of mostly proton the concentrated beam neutral within at particle collision flux projected arriving to from the detector the plane. IP, which is the direction Figure 4.2 number of shower particles after 6 X shows energy resolution up to 7 TeV.after Here the the open saturation circles effect are of the the data SciFi before has and been the taken filled into circles account. Detector geometry and acceptance The LHCf detectors are installed between twofrom beam pipes the embedded in IP. the At TAN absorbers secondary this particles location, so that the only neutral inner particles beam such as separation dipole has swept away all the charged 2008 JINST 3 S08006 rad µ 20 mm rad, the × µ rad] µ Energy (GeV) Direction [ region covered by the detector will be T Detector #1 Detector #2 3 10 40 mm calorimeter will be cut off by the beam-pipe – 22 – × correlation plot of photons for 7 + 7 TeV proton collisions. The γ Distance from the beam center [cm] T -P γ 2 0 50 100 150 200 250 300 350 400 0 1 2 3 4 5 6 10 1 0 -1

-2

acceptance of detector 1 defined by the vertical aperture of the beam pipe in the

0.8 0.6 0.4 0.2

Position resolution (mm) 10 resolution Position 10 T Geometrical Acceptance Geometrical P 43.8 mm at the D1 magnet location. With a beam crossing angle of 140 ± : Position resolution of SciFi up to 7 TeV. The effect of saturation of the SciFi is taken : Geometrical acceptance of detector 1 (solid blue) and detector 2 (dotted red) for single 20 mm calorimeter at the center of beam-pipe where center of the flux of neutral particles × Figure 4.5 shows the E -ray events as function of the distance from the beam axis. curve shows the D1 magnet. The upper and the lower curves correspond to the beam crossing angles of 140 aperture of Figure 4.4 γ 20 mm exists. In this case, about half of the 40 mm center of neutral particle flux moves downward by 2 cm. Inenhanced. this case the center of 20 mm into account in the filled circles but not in the open circles. Figure 4.3 calorimeter will be adjusted downward by 2 cm and the P 2008 JINST 3 S08006 1 F can be recorded by X γ T -rays, one each hitting rad γ µ [GeV] 0 rad, respectively. µ gamma rad E µ trajectory at production to the detector detection are shown in figure 4.6 for 1, 0 0 π rad. and 0 -rays with energies higher than 2 TeV can π γ µ 140 1000 0.1 – 23 – correlation plot. High energy photons with small P 100 γ T 1 0 -P

γ 1.4 1.2 0.8 0.6 0.4 0.2

gamma T P [GeV/c] mass peak can be used for the absolute calibration of the energy scale. It also helps for 0 : The E π production angle. 0 rad,respectively. The photons that fall in the area under the curves will be detected by mass can be reconstructed in the invariant mass distribution of two π µ 0 The π reconstruction 0 and 0 LHCf. From these curves it can be seen that almost all the two tower calorimeters ofafter detector taking 1 into or account detector 5% 2. energy resolution The and expected 0.2 mass mm resolution position resolution. isrejection of about beam-gas 5% interactions by giving avertex. constraint The for acceptance location of of the detector neutral2 1 pion and and production 5 detector TeV. 2 In these for estimations,on the the crossing horizontal angle is midplane zero asbetween and the shown the impact in small point calorimeters figure defined are by1.4.and located extrapolation the of center The the of lower the neutral horizontal particleas axis flux the from gives the the IP. The distance top horizontal axis expresses this distance Figure 4.5 be detected by LHCf. π The the LHCf shower counter.from The the curves configuration show of geometrical the cutscurve beam (red) for pipe correspond our to and shower beam magnets. crossing calorimeter angles arising The of upper 140 curve (magenta) and the lower 2008 JINST 3 S08006 6 rad] µ 45 2.0TeV 1.0TeV 5.0TeV Direction [ Energy 0 π energies are plotted as func- 23 0 π 100 150 200 250 300 350 400 450 0 0 position from the beam center [cm] π 01 05 0 01 03 02 05 04 .

. . . .

0 0 0 Geometrical Acceptance of Arm#2 Arm#2 of 0 Acceptance Geometrical 0 – 24 – ’s. Left and right plots show the acceptances for detec- 6 0 rad] µ π Direction [ Direction 2.0TeV 1.0TeV 5.0TeV Energy 0 π trajectory at production to the plane of the detector. 0 π 100 150 200 250 300 350 400 450 12345 0 0 position from the beam center [cm] : Geometrical acceptance for π 0 05 0 01 02 03 05 04 .

. . . . In this article we briefly report preliminary results for detector 1 from the SPS2007 beam test. The beam test setup is illustrated in figure 4.7 . One of the detectors was placed on a movable

0 0 0 0 0 Geometrical Acceptance of Arm#1 Arm#1 of Acceptance Geometrical Figure 4.6 tor 1 and detector 2, respectively.tions Acceptances of the for distance three between different theextrapolating center the of the neutral particle flux and the impact point defined by table in the beam area.gered by Data scintillators from placed in the front calorimeters ofstrip and the detector detector. position (ADAMO) At sensors [22] the installed was same between time, recordedrecorded. data the when These from detector trig- data an and external are the silicon used triggercomparison to scintillators with precisely were the determine also internal the position incident sensitive position layers. of the beam particle for A detailed report on the analysis as well as results for detector4.2.1 2 is in preparation. Results for the calorimeters In the beam test, thein PMTs which were operated PMTs at were severalcalorimeters operated different is gains. with optimized to a Low cover gain gainmodes 100 is GeV of ranging a to from 1 default 7 000. 3 TeV mode, 000 electromagnetic toresolution showers. With 10 and 000 Some this possibly are higher overcoming gain, optimized gain unexpected for the noisewhich measurements in are dynamic below only the 1 range available DAQ TeV in electronics. with of the improved For SPS the the test beam, muon the runs, PMTs were operated at the highest gain of about 4.2 Results of SPS beamThe tests assembly of the detectorsCERN was SPS finished North in Area April H4 2007 beamlineexposed and from to their 24 electron, performance August hadron was to and tested 11and muon at September 200 beams. the GeV, 2007. hadron Electron Both beams beams detectors with withof were energies energies 150 of GeV of were 150 50, used. and 100, 350 150, GeV 180 and a muon beam with an energy 2008 JINST 3 S08006 0mm – 25 – 730mm 1050mm 2 mm from the nearest edge of the calorimeter are used. The energy resolutions > : Setup of the SPS experiment. Beam enters from right along the red arrow. Two plastic The gain calibration of each plastic scintillator layer was carried out by using the electromag- Summing up the signal in all the layers except the first, the energy resolution is defined as The position of the shower axis was determined by the SciFi layers by finding the peak of to measure a single MIP. The relative gains of the different modes were measured during the 5 the lateral shower shape. GainSciFi calibration layer. was Position carried resolution was out checked for withcorrect all ADAMO. for The of the measured the shower position axis scintillating dependence was fibers of usedeffect in to light by each referring yield to from the plastic previously scintillators measured and non-uniformity the maps shower and leakage shower leakagenetic studies. showers produced by electron beams.for a Figure 4.8 100 GeV/cshows electron an ADCparticles beam. distribution is The at also the energy shown. 4th that By layer ergy is comparing deposited expected the by from two shower MC distributions particles simulations abeam is of conversion energies factor were determined the obtained from for shower and ADC each are totors compared layer. en- are with consistent Conversion each at other factors the in for 2% figure level different deposited4.10. for by 50 We found a - these single 200 GeV fac- MIP, the electrons. muonthe To check data relative consistency was PMT with analyzed the gain as energy difference shownwas for in taken figure the into4.9. different account. In HV The this settings pedestal comparison, also for fluctuations taken the of into 8 electron account AD and in counts thedistributions. the (rms) muon MC due runs to calculations. electrical We noise can was observe good agreement between theroot-mean-square two of the distribution. Hereconstructed to showers lie for which the incident particle position is re- Figure 4.7 pre-assembly calibration for each PMT as described in section 2.2. obtained in the beam testgain and operation. in Resolution MC was simulationnoise worst are level for plotted during 50 in the GeV figure SPS with beam4.11 low test. gainfor (450V high The HV) gain electrical due and noise to low was the negligible electrical for the high gain mode scintillators indicated by blue rectangles wereshow used the to silicon trigger tracker, ADAMO, beam placed particles. inrectangle. Five front open The of rectangles two the LHCf black-blue detector structuresand that shown ADAMO is in were drawn placed the as on detector a a are big movable grey the stage. calorimeters. The detector 10 2008 JINST 3 S08006 dE [MeV] ADC counts ADC counts Beam Test Simulation – 26 – Beam Test Beam Simulation 00 100 200 200 300 400 400 0

0 -50 0 50 100 150 200

50

800 600 400 200 N

∆ 150 100 N ∆ : The ADC distribution at the 4th scintillation layer for 100 GeV electron showers : The ADC distribution at the 4-th scintillation layer for 150 GeV muon tracks (solid). Figure 4.9 The energy distribution expected from MC calculations (dashed) is also shown. (600V HV). In any case, weulations have showing obtained the excellent energy agreement resolution between is the satisfactory data for and the the experiment. MC sim- Figure 4.8 (solid). The distributionshown. of deposited energy expected from MC calculations (dashed) is also 2008 JINST 3 S08006 50GeV 100GeV 150GeV 180GeV 200GeV Energy [GeV] Beam (450V) Beam (600V) Simulation(450V) Simulation(600V) – 27 – inside the calorimeter. The position of each SciFi is 0 Layer 0 50 100 150 200

0 2 4 6 8 10 12 5 0

10

E/E [%] E/E

4 2 0 ∆

-2 -4 A[%] ∆ : Energy resolution for electrons with two different bias HV values are given. The : Comparison of gain conversion factors obtained from electron showers of different results of MC simulation are also plotted with blue circles. 4.2.2 Position resolution of theThe SciFi position resolution of thelateral SciFi spread hodoscope of used electron incalibrated showers beforehand detector at by 1 detecting 6 has a X muon been trackof studied which the is by detector also [22]. using detected The by the center ADAMO placed of in the front shower is determined from the peak signal and the signals in Figure 4.11 Figure 4.10 energy. Here the relative differences from the 150 GeV beam are shown for each layer. 2008 JINST 3 S08006 m µ m (mm) µ -ray impact γ ADAMO = 159 y - Y σ ARM1 Y m in the Y direction. The µ 2 mm from the nearest edge were m in the Y direction. The results µ > m to 160 -ray energy. From a MC simulation of γ µ -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 0 ARM1-ADAMO Residuals ARM1-ADAMO 800 600 400 200 1000 20 mm tower. The electron beams were uniformly × – 28 – m. The same analysis has been carried out for electron µ m (mm) µ =160 ADAMO y m in the X direction and 230 = 172 σ x µ - X σ 40 mm tower was done at an electron beam energy of 100 GeV, and the ARM1 X × m and m in the X direction and from 210 µ µ =170 x σ : Position resolution of the SciFi in detector 1. Distributions of the difference between m to 170 µ A very preliminary data analysis has been done to give an estimate of the spatial resolution for -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 0 ARM1-ADAMO Residuals ARM1-ADAMO 800 600 400 200 1000 the system, we calculated anfor expected photon impact energy greater point than reconstruction 100 resolution GeV. better than 100 the silicon based system of detector 2.of This analysis the was done trajectory using ADAMO of fortrajectories the each reconstruction of particle single minimum hitting ionizing the particles. calorimeter. ADAMO was designed measuring the Figure 4.12 the shower center and incidentare particle plotted. position The results determined for by X SciFi and and Y directions ADAMO, are respectively, shown in thethe two left adjacent and fibers right weighted plots, by their respectively. is AD counts. compared The center with determined the by thedifferences incident SciFi between hodoscope particle these position measurements estimatedfor in by 200 the GeV ADAMO. electrons X The observed and by distributions the Y of 20 directions mm the are presented in figure 4.12 are very close to the 0.2information mm between desired the position resolution LHCf for detectoran energy and above improvement ADAMO 100 in GeV. has resolution Mis-alignment not is expected. yet been taken into account, hence 4.2.3 Position resolution of theThe silicon silicon tracker based tracker ofpoint detector on 2 the allows calorimeter, that for improves a with very increasing the good reconstruction of the scanned over the surface of the calorimeter, and the events selected for this analysis.deviation The of distributions can bebeams fit of 50, by 100, Gaussian 150 and distributionsfrom 180 with GeV. 200 The a resolution becomes standard slightly betteranalysis with for increasing the energy 40 mm resolution obtained was 170 2008 JINST 3 S08006 0 inside 0 ±± 0.00112 0.00112 ±± 29.64 / 15 29.64 / 15 ±± 508.7 508.7 (mm) -ray pairs entering in the γ m ’s, a carbon target of 60 mm 0.04861 0.04861 µ 0 ADAMO 0.003537 0.003537 π -X = 49 ARM2 mass reconstruction, an experiment σ X m. 0 inside the calorimeter and the impact / ndf / ndf 22 µ π Sigma Sigma χχ Prob Prob Constant Constant Mean Mean 0.01328 0.01328 0.001311 0.001311 18.018.0 0 – 29 – mass reconstruction capability 0 π m for minimum ionizing particles, the width of this distribution is dominated µ -1 -0.5 0 0.5 1 : Position resolution of the silicon strip sensor in detector 2. Distribution of the dif- 0 100 200 300 400 500 ARM2-ADAMO Residuals ARM2-ADAMO Figure 4.13 shows the distribution of the differences between the measured positions of the 4.2.4 Demonstration of To demonstrate the capability ofwas performed the at LHCf the SPS detectors H4 for thickness test was beam placed with detector 10 1. m in To produce beam. front of With the this detector geometry and and thecalorimeters. energy, target we The was PMTs can exposed were expect to operated typically a atthe 20 350 800 GeV GeV gain V. With proton at this the voltage nominal theso voltage gain that is of both 40 450 calorimeters V. times To were higher trigger required than on to have gamma-ray signals pairs, corresponding the to trigger more than logic 40–80 was MIPS set in Figure 4.13 ferences between the measured positions of the shower centers of 200 GeV electrons at 6 X in good approximation by thethat LHCf the center silicon of spatial a resolution. 200 GeV These e.m. first shower results can show be reconstructed therefore on the silicon layer located at 6 X the calorimeter and the impact points extrapolated at the same depth by using the ADAMO tracker. shower centers on thepoints LHCf extrapolated silicon at layer the located sametrons depth at events by 6 has using X been the used ADAMOresolution for tracker. of this A a analysis. data few Because set the of ADAMO 200 GeV system elec- has an intrinsic spatial inside the calorimeter with a spatial resolution of about 50 2008 JINST 3 S08006 ’s. Here we note that the 0 π -ray pairs observed in the SPS test γ -ray pairs, each having energy more than γ (135 MeV) implies the calibration and analysis 0 π – 30 – (135 MeV) implies the calibration and analysis procedure 0 π Invariant mass [GeV] 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 protons entered the carbon target, 300 000 events generated the trigger and were

-rays in this test (20–50 GeV) was below the range that will be investigated in 0

7 γ 60 50 40 30 20 10

N/0.01GeV 10 -ray pairs. ∆ γ × : Invariant mass distribution calculated from the 100 GeV). > After 6 procedure are working correctly. The background ishit caused by the uncorrelated two pairs calorimeters those simultaneously. accidentally Theevents background distribution in was the evaluated by two shifting calorimeters the figure so4.14 thatby any dashed line correlated and pairsenergy confirms disappear. range the of peak The is result really isLHCf produced ( also by shown in 20 GeV, are identified inpositions 0.6% of of the pair, these the recordedin invariant figure mass events.4.14 . was calculated. A From clear The the peak invariant energies at mass and the distribution mass is the of shown transverse the any of the layers from 2 tothat 5. none of At the the same last time, two to scintillation reduce layers the in large both proton calorimeters background,recorded. have we a required Data signal reduction exceeding was 20 carried out MIPs. i.e., based on position the processes determination described based inlight the on previous collection, the sections, leakage SciFi correction, data,The and 2 mm difference conversion between edge from the cut, measured PMTaccounted correction signals gain for for in to based non-uniform the on energy the nominal deposited. laser beam calibration tests data. and Clear in this special run was also beam. A clear peakwere at working the correctly. mass The of backgrounduncorrelated shown in the dashed histogram was calculated by using Figure 4.14 2008 JINST 3 S08006 - - 0 γ γ 10 × particles 8 60% of the ∼ C ion beams. Ab- 40% to 12 ∼ -rays showed a decrease of light γ Gy/h and increasing rate from 2 4 10 × -rays. The scintillator light outputs are almost γ Gy/h, 8 – 31 – 4 C beam. Irradiation of the fiber light-guide showed a 12 10 × -ray tests, similar materials were irradiated by a 100 TBq γ -rays. The long-term recovery was measured by using a radioactive beta-ray γ . We have tested the tolerances of our plastic scintillators and clear-fiber light- 1 − s Co Radiation Facility of Nagoya University. Effects of irradiation such as a change in 2 C beam itself and for UV light (350 nm) from a filtered Xe flash lamp (Hamamatsu − 60 12 Sr) for several days or more. Figure 4.15 shows the variation of the scintillator and light Gy/h) were compared. For . The degradation of scintillator light outputs were evaluated by measuring the signal for 4 90 2 cm − 10 In conclusion, the plastic scintillators can be damaged by irradiation with heavy ions and For the heavy ion test, two kinds of plastic scintillator (EJ-260 and BC-404) and a clear- 29 × cm 1 Co source. The absorbed dose was calculated from the geometry of the source and target materi- − source ( 60 als. Two dose rates (22 Gy/h andand 250 Gy/h) the were irradiated used materials. by changing Thethe the distance evaluation Xe between of flash the the lamp. source light Theboth output short-term heavy was recovery ions done of and damage by was using also UV measured light just from after irradiationguide by light outputs for irradiation by heavy ions and to 8 small decrease of light transmission forparency the wavelength due of to 490 nm irradiation. because The ofoutput the measurement similar decrease for to in irradiation that trans- for by heavy100 Gy ions. and The light to output 80% decreasesfew at to hours 500 90% Gy. after of finishing The the the initial damagedor irradiation, value scintillators more, but around a showed the clear a extent recovery of tendency wasinitial recovery to observed light was and recover output very the within before small. light a irradiation. output After increased one from day constant up to ten Gy100 Gy of or absorbed more. dose Most and samplesat show then the a decrease decrease maximum to of absorbed light 90%irradiation dose output of measured to of the by 40% 30 UV pre-irradiation of kGy. light the value or pre-irradiation There at by value was the no significant difference in the effects of the weak L4633-01). Different irradiation rates (3 rays at the fiber light-guide (CLEARPSM, Kuraray)sorbed were radiation irradiated dose was with measured 290plastic MeV/n by scintillators. an air The ionization final chambers integrated coupled with dose measurements was by 30 kGy with a beam intensity of 10 rays but the decrease of thedependence light of output radiation is damage not large onrate, for and the doses so type of on of interest were for scintillator,days observed. after LHCf. the irradiation. Partial No type Normally, recovery the significant of of LHCf decreased detectors radiation,one will light week receive the output a oepration. irradiation dose is of This observed several is over tens enough of several Gy to during complete the measurements unless background event rates guides to ionizing radiation.a The synchrotron test at experiments HIMAC were of NIRS carried (National out Institute with of a Radiological heavythe Science, ion light Japan) output beam and from with from the plasticscintillation scintillators photons and and change also in the transparency recovery from of radiation the damage light with guides time for were the measured. 4.3 Results of radiation damageThe tests LHCf detectors will beal. exposed (2003) calculated to the a absorbed considerable dosethe distribution amount LHCf around of detector the would ionizing TAN]. [23 receive radiation. a Theirof maximum result Mokhov 10 radiation showed et dose that of 10 Gy/day at a nominal luminosity 2008 JINST 3 S08006 -rays. γ – 32 – : The variation of the scintillator light outputs (EJ260 and BC404) and light guide are very high and the runby the must laser be calibration extended. system A and small the decrease accuracy of of energy light measurement output will can not be be corrected affected. for Figure 4.15 transmission for irradiation by heavy ions and 2008 JINST 3 S08006 . After a 1 − s 2 − cm 29 eV. In this paper, we have given an ex- 17 – 33 – 140 m from IP1 where the neutral particle absorbers ± . The event rates are expected to be high enough that LHCf 1 − s 2 − cm 30 range that can be measured and to remove the detectors from unnecessary T . 1 − s 2 − Two LHCf detectors are installed at 10% due to radiation damage. Radiation damage will be monitored and corrected for with a cm ∼ 30 can get all of its data in one week of LHC operation at the luminosity of 10 radiation damage when they are8.4 not to in infinity. use. Data Theing experiment acquisition room, covers during USA15. a LHC An pseudo operation event rapiditydeveloped will tagging range to scheme be correlate from based carried LHCf on and out thequisition ATLAS in time events and the stamp for electronics of possible ATLAS are count- the further optimized LHC analysis.with to clock operate luminosity Detectors, has during below data been the 10 ac- early phases of LHC commissioning The LHCf is an experimentin to order measure to very calibrate forward theCosmic-Rays neutral hadron at particles interaction a emitted models in used laboratory LHC in equivalent simulation collisions energy of of Extremely 10 High Energy Summary perimental overview, a description ofsimulation details of of performance of the the instrumentation detectorsof and during SPS LHC data test operation beam acquisition and experiments. system, reported preliminary results (TAN) are located. Each of theters two made detectors of is tungsten composed plates, oftive plastic two layers scintillators independent are and sampling scintillation position calorime- fibers sensitive layers.detectors and for multi-anode The photomultipliers detector position 2. for sensi- detector Because 1compact, of but and the are silicon still limited strip capable space of forcient measuring resolutions. installation, energy and these Simulations position predict calorimeters of that are theresolution the very incident as energy particles good resolution with as is suffi- 0.2 better mmin than at 100 5% SPS GeV; and these test the predictions have position beams beenbackground confirmed at events by generated CERN. measurements by The beam-gas use interactionsconditions during may of early not front LHC be operation scintillation as whentors good counters vacuum to as is anticipated. increase expected the The P to detectors are help equipped reduce with vertical manipula- week of operation under theseby conditions, the output ofpulsed the laser plastic calibration system. scintillators The will10 LHCf be detectors degraded will be removed once the luminosity exceeds Chapter 5 2008 JINST 3 S08006 – 34 – This work is partly supported byfor Grant-in-Aid for Scientific Scientific Research Research on (B:16403003), Priority Grant-in-Aid and Areas (Highest Grant-in-Aid Cosmic Rays: for 15077205, YoungSports, 1733004, Scientists Science 19012003) and (B:18740141), Technology (MEXT) byMitsubishi of Foundation the Japan. in Japan Ministry This and of byreceipt work of Istituto is Education, a Nazionale also Japan di Culture, Society partially Fisica for supported Nucleareacknowledged. the by (INFN) The Promotion in authors of the Science would Italy. (JSPS) like The Research to Fellowship thank (H.M.) CERN is for also the support shown to our experiment. Acknowledgments 2008 JINST 3 S08006 , 92 479 Nucl. Instrum. , Intl. Cosmic th , Merida Mexico Phys. Rev. Lett. , , CERN-LHCC-2007-001, Proc. of 30 , (1998) 1163. 81 (2003) 258. Intl. Cosmic Ray Conference (2007) 938. 50 th – 35 – ’s in the fragmentation region at the SppS collider, 318 0 π Phys. Rev. Lett. Correlation of the Highest-Energy Cosmic Rays with , Science Proc. of 30 , , The TOTEM Experiment at the CERN Large Hadron Collider ATLAS Forward Detectors for Measurement of Elastic Scattering Zero Degree Calorimeters for ATLAS IEEE Trans. Nucl. Sci. The UHECR spectrum measured at the Pierre Auger Observatory and Measurement of the Flux of Ultrahigh Energy Cosmic Rays from , (1990) 531. Extremely high-energy neutrinos and their detection. Astrophys. J. 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