Scintillation Detectors in Nuclear and High-Energy Physics - Based on Inorganic Scintillators - R

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Scintillation Detectors in Nuclear and High-Energy Physics - based on inorganic scintillators - R. W. Novotny 2nd Physics Institute, University Giessen

BaF2 • short history • what is required and what can be provided? • basic properties of scintillators • particle detection PWO • energy measurement • particle identification/discrimination • time-of-flight • pulse-shape analysis • phoswich technique CeF3 LYSO • photon/electron detection • low energy • calorimetry • outlook into near and far future history of scintillators

SrI2:Eu 1968/2008 LSO:Ce,Ca 2007

LuI3:Ce 2003 LaBr3:Ce 2001 LYSO:Ce 2001 LuYAP:Ce 2001

LaCl3:Ce 2000 LuAP:Ce 1994 LSO:Ce 1982

Invention of the photomultiplier tube ZnS

CdWO4 Late 1800s …. BaPt(CN)4

M. J. Weber, J. Lumin. 100 (2002) 35

discovery and development of new scintillator materials are strongly correlated with basic research and technology in physics ... historical development:

• 1895 discovery of X-rays tilting table for fluoroscopy, Paris 1896 • 1896 natural radioactivity low energetic probes of a few MeV • 1931 Van de Graaft - generator ( TANDEM) linear accelerator principles: HF-resonators cyclotron energy of reaction products increases according to the available bombarding energy: MeV TeV investigations in nuclear, medium and high energy physics

• near Cb -barrier: nuclear excitations, „binary“ reactions single particle or photon detection • near Fermi-energy: high excitations, DIC, multi-fragmentation multi-particle production, high photon multiplicities • medium ... relativistic energies: study of hot and compressed matter meson production, global parameters similar development in HE physics: exploratory experiments, resonance studies, jet-physics, Higgs - search, ...

research trend in astrophysics very similar ! detection/identification/discrimination of charged and neutral hadrons dE/dx limitation due to the large hadronic interaction length dE ~m⋅ z2 λ >> Xo dx

• complete stopping total kinetic energy << 1 GeV β⋅γ energy no shower detection • energy loss ∆E MIP

position • limited by the size of the individual detector module velocity • time-of-flight for low-energy particles

• ∆E-E technique PID • intrinsic sensitivity (pulse shape) detection/identification/discrimination of charged and neutral hadrons

neutrons: En < 20 MeV (n,γ) capture reactions n+63 Li →α+ H n+10 B →α+ 7 Li nHepH+33 →+

En > 20 MeV (n,p) En > 1 GeV hadronic shower electromagnetic probes 7 183 7 A 1 σ = α⋅ 22 ≈ ⋅ ⋅ pair 4 re Z ln 1/3 photons 9 Z 9NA0 X

electrons Bremsstrahlung

dE E EM − = dx X0 shower

1 radiation length X ~ o Z2 electron energy / MeV requirements for electromagnetic calorimetry:

energy and position measurement of e+/- and photons invariant mass reconstruction

decay of neutral mesons γ in 2 photons π0 π0 counts γ η 2 m γγc = 2E1E2 (1 − cosΘ12 ) mγγ / MeV electromagnetic shower

visualized with a Wilson chamber 30 cm NaI(Tl) Eγ 50 MeV γ 20 cm 500 MeV 5 GeV 50 GeV

PbWO4 10 X0

γ 2RM

G4-simulations experimental conditions ref.: LHC/FAIR

beam luminosity: up to 1034 cm-2 s-2 events/interactions: up to 109 s-1 high multiplicities: heavy ion reactions ! high occupancies: large shower dimensions high radiation dose: in 10 years neutrons: 1017 n/cm2 γ−rays : 107 Gy

• fast response (trigger, read-out) • high granularity • compact (operation in magnetic field) • radiation hard basic processes in luminescence centre – LC inorganic scintillators Intrinsic or Dopant e ionic crystal conduction band host material

Egap > ~ 4 - 12 eV

valence band VIS 400 - 800 nm 3.1 - 1.6 eV h UV 180 - 400 nm 6.9 - 3.1 eV VUV < 180 nm > 6.9 eV thermalization ideal absorption in air transport model

C.W.E. van Eijk scintillator basics scintillation mechanism = conversion of ionization energy into visible light (hνrad) hν ⋅ N general efficiency: η = rad ph Edep

N ph relative light output: L R = Edep ξ eh = β⋅ Eg Eg : band − gap β = 1.5 − 2 : ionic crystals energy to generate an e/h-pair: β = 3 − 4 : covalent binding

thermalization

Eγ Nph = ⋅S ⋅Q β⋅Egap C.W.E. van Eijk, NIM A460 (2001) 1 relevant properties of the most common crystal scintillators

crystal NaI(Tl) CsI(Tl) BaF2 CeF3 BGO PbWO4 LYSO 3 density g/cm 3.67 4.51 4.89 6.16 7.13 8.28 7.1 radiation length cm 2.59 1.85 2.06 1.68 1.12 0.89 1.2

Moliere radius cm 4.8 3.8 3.4 2.6 2.3 2.1 2.4 nuclear interaction 41.4 36.5 29.9 22.0 18.0 21.0 length cm luminescence nm 410 565 310 310 480 420 420 420 195,210 340 decay time ns 230 1300 620 30 300 5-15 40 35 0.6 9 dLY/dT %/oC -1.8 ~ 0 ~ 0.3 -0.8 -1.8 0 at RT 0 relative light output 1 1 0.25 0.10 0.09 0.02 1 compared to NaI(Tl) 0.04 typical inorganic scintillators

identical volume: 3 (X0)

γ-ray spectra measured with different scintillators emission and transmission spectra of different scintillators

temperature dependence of different scintillators how everything started: R.Hofstadter, Phys.Rev. 74 (1948) 100

NaI with source

NaI without source particle detection:

low beam and scintillators cannot compete with solid state or gaseous detectors particle energies: due to statistics

higher energies scintillators allow large and granular solid angle, stopping power > 5 MeV/u and fast response (but: also depending on photosensor) most common: CsI(Tl), BaF2, BGO, ... NaI(Tl)

MSU Miniball R.T.De Souza et al.,NIM A295 (1990) 109 DWARF Ball/Wall D.W.Stracener et al., NIM A294 (1990) 485 AMPHORA D.Drain et al., NIM A281 (1989) 528 MEDEA E.Migneco et al., NIM A314 (1992) 31 particle ID:

γ + C → π0 + X + ... 250 • time-of-flight BaF2 (TAPS) 200 E (MeV) 150 2 AGeV Ca+Ca 100 flight ns / flight - 50 of -

0 0 2 4 6 8 10 time t (ns)

time resolution: σt > 85 ps energy / MeV C.W.E. van Eijk BaF2

kinetics of the two fast scintillation components at λ = 195nm and λ = 220nm

P.Schotanus et al., NIM A259 (1987) 586 particle ID: • ∆E-E telescope via phoswich technique combination of a fast and slow scintillator common readout with photomultiplier

• two organic scintillators: NE102A / NE115 • fast plastic and slow inorganic scintillator: NE102A / BGO NE102A / CsI(Tl) 35MeV/u Ar+Au H He fast

MSU Miniball slow • identification via pulse shape analysis PSA due to intrinsic luminescence properties: scintillation components show different response to

electromagnetic or hadronic probes CsI(Tl), BaF2, ...

time proton

s s

a n f to - ho photon E p

ns oto pr fast component

total light output E-total signal integration width

plastic BaF -detector VETO 2

identification of charged and neutral events • identification via pulse shape analysis PSA all events

reaction products: 2 AGeV Ar + Ca

charged neutral events events protons photons

n • identification via pulse shape analysis PSA visualisation of PSA in polar coordinates

transformation:

radius / MeV short radius= short2 + long2 , angle= atan( ) long

protons π+ photons

angle / ° time • identification via PSA and charged particle

tt phoswich technique ss

EE ns t to plastic/BaF d ho 2 p p

fast component

total light output E-total signal integration width

phoswich: plastic/BaF2

BaF2-detector

plastic scintillator common PM-read-out MEDEA @ LNS Catania 180 BaF2 detectors (10X0), PM-readout 120 plastic phoswich

plastic BaF2 MEDEA @ LNS Catania particle ID via TOF and PSA

plastic phoswich: NE102A/NE115

BaF2: PSA

H fast photons He

total Miniball @ MSU

188 fast plastic / CsI(Tl) telescopes Coverage: 89% 4π

AMPHORA detector @ SARA

neutron detection DWARF Ball/Wall 105 plastic/CsI(Tl) elements

particle ID

detection of γ-rays in a Ge detector in coincidence with charged particle to select reaction channels INDRA@GANIL/GSI

PID: PSA of CsI(Tl)

Si-CsI(Tl) telescopes CsI(Tl) PSA particle detection: at medium and high energies secondary reactions and development of hadronic shower options: TOF, ∆E vs TOF correlations 180 MeV d

calorimetry, but interaction length ~ 10 X0 counts

BaF2 “proton calibration” energy / a.u.

t d p Ep= 50 MeV Ep= 200 MeV p π p

π counts

flight relative to photonsns / relative - of flight MIP d t d time

15 cm PbWO4 energy / MeV particle detection: neutron detection TAPS neutron efficiency depends strongly on energy and detector threshold

En < 300 MeV: neutron identification via exclusively measured reaction γ + p π0 + π+ + n

efficiency: En > 750 MeV 17% efficiency efficiency

threshold

reconstructed energy / MeV particle detection: thermal neutron detection

capture reactions of 6Li n + 6Li (7.5%*) → 3H + 4He (4.8 MeV) σ = 941 barn @ 1.8 Å

6Li glass 6LiI:Eu 662 keV neutron 1332 keV ~ 4.1 MeV 662 keV neutron

By courtesy of Paul Schotanus, Scionix By courtesy of Paul Schotanus, A.Syntfeld et al, IEEE Trans Nucl Sci Scionix vol 52, no 6, 3151-3156, 2005 photon detection: spectroscopy with scintillators could not compete with Si or Ge solid state detectors at very low energies !

NaI(Tl) but: high efficiency provides optimum material for anti-Compton suppression (BGO most common) counts Ge

energy

Euroball, Eurogam, Gammasphere, ...

energy / keV photon detection: response to low energy photons

example: BaF2 @ RT fast γ 60Co α

α total

total 137Cs 1.3 MeV α

fast advantage of Ce3+ luminescence

Ce3+ luminescence center why Ce3+ ? e conduction band

relaxation 5d

core excitation emission and 1 electron in 4f 4f state valence band h

5d → 4f allowed dipole transition fast response τ ~ 20 ns

C.W.E. van Eijk Lu SiO :Ce LuAlO :Ce RbGd Br :Ce crystal 2 5 3 2 7 LaCl :10%Ce (LSO) (LuAP) 1) 3 density g/cm3 7.40 8.39 4.8 3.9 radiation length cm 1.1 1.1 2.03 ? luminescence nm 420 365 415 350 decay time ns 40 17 50 20 440 330 2000 relative light output 0.63 0.30 1.4 ~ 1 compared to NaI(Tl) LaCl3:Ce

LaCl3:Ce 32keV Ba 4 mm x 6 mm ΔE/E = 3.1%

La X-ray escape peak Counts

400 500 600 700 800 0 200 400 600 800 Energy (keV)

E.V.D. van Loef, P. Dorenbos, C.W.E. van Eijk, K. W. 4” x 6” Krämer, H.U. Güdel, Appl. Phys. Lett. 77 (10) (2000) 1467. ΔE/E = 4.1% 3+ LaBr3:Ce LaBr3: 5%Ce energy resolution 1.2 Pulse height spectrum 662 keV gamma rays

1.0 61,000 ph/MeV 2.8 % FWHM 0.8 NaI:Tl light yield 70,000 photons/MeV 0.6 6.5 % R=2.9%FWHM (NaI:Tl 40,000 ph/MeV) 0.4 counts (arb. units)

0.2 decay time 16 ns

0.0 (NaI:Tl 230 ns) 0 100 200 300 400 500 600 700 800 energy (keV)

E.V.D. van Loef, P. Dorenbos, C.W.E. van Eijk, K.W. Krämer, H.U. Güdel Appl Phys Lett 79(2001)1573 380 scintillators become comparable to Ge … ∆E 1+ v(M) R = = 2.35 E Nphe v(M) = 0.1 ... 0.2

fundamental limit - Poisson statistics - v(M) = 0.1 1995

energy resolution for Eγ=662 keV as a function of the photoelectron yield in the PMT

P.Dorenbos , NIM A486 (2002) 208

non-proportionality ! photon detection: large size NaI(Tl) crystal @ BNL

Eγ < 50MeV

24cmØ x 35 cm shielded by an active annular plastic array

resolution: 2.2% (FWHM)@ 22 MeV

A.M.Sandorfi et al., NIM 222 (1984) 479 photon detection: high efficiency, modularity and large solid angle 4π NaI(Tl) DA-HD Crystal Ball

Spin-Spectrometer @ ORNL

72 NaI(Tl) modules 162 NaI(Tl) modules 17.8 cm deep, canned 20.0 cm deep, canned inner open sphere 32cmØ inner open sphere 50cmØ photon detection: 4π BaF2 arrays Crystal Castle @CRN Strasbourg

42 modules 15 cm deep, canned open sphere 20 cmØ

4π BaF2 Karlsruhe 42 hex. crystals 10 cm diameter, 14 cm long study of neutron capture En: 5 - 200 keV γ nuclear structure physics detection of -decay cascade

significant background due to radiactive contaminations

480 BGO crystals ∆ϕ = 11.25° GRAAL – experiment 24 cm length ( 21 R.L.) ∆ϑ = 6°÷10° 15 sectors in ϑ, ϑ ∈ [25°,155°] ∆Ω = 0.9 x 4π 32 sectors in ϕ, ϕ ∈ [0°,360°] @ Grenoble 32 NE102 scintillators 128 Φ = 1.5" PMT l = 43 cm BGO 352 Φ = 2.0" PMT h = 5 mm

study of photonuclear reactions Rugby Ball photon spectrometer TAPS

σ [662keV,137 Cs]= 4.9% (15.1%) fast: 195, 210 nm E slow: ~ 310 nm

Ø / E / TAPS detector: 12X0 59mm σ fast

slow

photon energy / GeV

σ lineshapes measured with tagged photons [10 GeV] = 5.1% shower leakage ! E TAPS: the modularity allows large flexibility ... operating since almost 15 years

TAPS/CERES@CERN cluster structure @GANIL

two- arm concept @GSI TAPS A2@MAMI 511 modules Mainz tagged photon facility Eγ< 1.5GeV on-line data complete new readout CeF3 large size each tower consists of 2-4 elements total length ~ 400mm ~ 25 Xo individually wrapped ?. 3500 2 u Eγ = 55 MeV 30x30mm . read-out with PM-tubes a 3000

/ 227 MeV

s t 2500 480 MeV σ 2.17% n = + 2.70% u 2000 E o experiment E[GeV] c 20x20mm2 1500 769 MeV Eγ=54.6 MeV 1000 GEANT 500 σ/E=11.5%

0 0 200 400 600 800 1000 energy / MeV but: improved excellent time resolution ( PM read-out ) material needed σ < 170 ps E.Auffray et al. NIM A378(1996)171 t e, µ, π: 10 – 150 GeV/c response σ/E ~ 0.5% @ 50 GeV at high energies with Si PD read-out the advantage of homogeneous calorimeters based on inorganic scintillators:

P.Lecoq et al., NIM 2003 device crystal modules depth photosensor B where beam energy 3 10 X0 T GeV Crystal NaI(Tl) 0.7 16 PMT 0 SLAC - Ball MAMI 1.5 Crystal Ball 22Na

σ 2.7% = E 4 E / GeV • 672 NaI(Tl) crystals • energy resolution: 3.5% @ 300 MeV 2.6% @ 1 GeV • solid angle: 93% von 4π Crystal Ball

the famous charmonium spectroscopy device crystal modules depth photosensor B where beam energy 3 10 X0 T GeV Crystal CsI(Tl) 1.4 16 SiPD 0 LEAR Barrel ELSA 3

σ 2.0% = E E / GeV Crystal Barrel detector concept

CsI(Tl)

WLS

PD read-out

the advantage of 4π Crystal Barrel + Midi -TAPS @ ELSA, Bonn

future set-up Wide Angle Shower Apparatus WASA @ CELSIUS - COSY

1012 CsI(Na) crystals readout via light-guide outside the iron yoke with PM

16 X0 device crystal modules depth photosensor B where beam energy 3 10 X0 T GeV CLEO II CsI(Tl) 7.8 16 Si PD 1.5 CESR 6

σ = 3.8%@180MeV E σ = 1.6%@ 5.0GeV E device crystal modules depth photosensor B where beam energy 3 10 X0 T GeV Belle CsI(Tl) 8.8 16 Si PD 1 KEK 8+3.5 BaBar CsI(Tl) 6.8 16 Si PD 1 SLAC 9+3.1

σ = 2.8%@100MeV E σ = 1.9%@ 400MeV E 16 Xo

σ 2.3% = ⊕1.35% E 4 E

position resolution Belle

mass resolution of reconstructed neutral pions KTeV

sub-mm position resolution

wall of CsI BESS III

Magnet yoke SC magnet, 1T RPC

TOF, 90ps

Be beam pipe

MDC, 120 µm

CsI(Tl) calorimeter, 2.5 % at 1GeV BESS III CsI(Tl)

• barrel: 5280 crystals, endcap: 960 crystals • each crystals (5.2x 5.2 – 6.4 x 6.4) x 28cm3 • readout: 13,000 photodiodes, 1cm × 2cm L3 @ LEP/CERN BGO

22 Xo ~ 12.000 crystals device crystal modules depth photosensor B where beam energy 3 10 X0 T TeV

CMS PbWO4 82 26 APD/VPT 4 LHC 7 ECAL

σ = 0.5%@120GeV E CMS ECAL

super- module

energy response PHOS @ALICE LHC PWO

PHOS (PHOton Spectrometer) area: 8 m2 17920 PWO channels (22x22x180mm3) 4.4m distance to IP 0 study of initial phase of HI collision: APD-readout@-25 C 0 via direct photons, high pT γ, π PHOS @ALICE LHC PWO

time response

σ 0.013 0.036 = ⊕ ⊕ 0.011 E / GeV E E E energy response HYCAL @ JLAB PWO PrimEx experiment (πo lifetime)

1152 crystals HYCAL @ JLAB position reconstruction

energy resolution in PWO array

πo reconstruction

σM= 2.3 MeV energy response in the different detector sections

invariant mass / MeV DVCS @ CLAS/JLab inner calorimeter

424 PbWO4 crystals stabilized at ~ +16oC readout by APD (5x5mm2)

160mm 13.33mm 16mm the PANDA detector at FAIR PWO-II 200mm (23Xo) • photon detection with high resolution over a large dynamicbarrel range: 10MeV < Eγ < 15GeV ~11.000 • high count-rate capability (2∙107 Annihilations/s) • nearly 4π coverage endcaps • sufficient radiation hardness ~4.000 crystals shashlyk• timing-type information for trigger-less DAQ concept SamplingTarget Calorimeter Spectrometer

4π detector for spectroscopy and reaction dynamics with antiprotons the Target Spectrometer: based on high-quality PWO-II prototype performance

deposited energy / MeV counts 858 MeV 158 MeV 1.44 GeV

σ / E / % PROTO 60 • MeV / energy incidentphoton digitization: shaping /peak E σ = 1 E . 78 / - GeV sensing ADC % + 0 . 69 % readout via SADC: further improvement

energy-resolution ( 3x3 matrix )

1 ns

time resolution prototype performance PROTO 60 15 GeV positrons

σ/E= 1.4%

σ(x,y)~1mm limited radiation hardness with respect to photons/hadrons reduction of PWO dose: 30Gy, 60Co absorption coefficient

24 GeV/c protons 1.8 x 1013p/cm2 150MeV protons fluence: (1.32±0.11)1013cm-2

G. Dissertori et al., NIM A684 (2012)57 impact on optical absorption coefficient at emission wavelength after proton irradiation

high probability of fission in PWO or LYSO: highly ionizing fission fragments

CeF3: shows significantly higher radiation hardness + thermal recovery recovery of radiation damage @RT

1,0 0,9 100@RT 0,8 Spontaneous o @T=LED_1550nm -25 C 0,7 90 LED_1300nm 470 nm 1 - 0,6 525 nm 640 nm 80 0,5 840 nm 0,4 70 LED_1060nm 0,3 935 nm ∆k (420 nm) ∆k / m 0,2 60 LED_940nm LED_464nm 0,1 50 0,0 recovery of normalized light yield / % 0 200 400 600 800 1000 1200 1400 1600 0 50 100 150 200 illumination time / min illumination time / min

applied integral dose of 60Co: D = 30Gy inorganic fibers

Micro-Pulling-Down Method: Investigated Scintillators:

installation @ FiberCryst LuAG:Ce LuAG:Ce fibers ( Ø 1.0 - 2.0 mm, length = 23 cm)

all fibers grown with the same low pulling speed fibers cut ~ 0.5 cm away from seed 241 Ce concentration varied response to Am

old sample (2010) μ ~ 1.0 cm-1, high pulling speed

0.15 % Ce

25 µm SiPM

best sample of run 1 – 2013 μ = 0.13 cm-1 , low pulling speed 0.075 % Ce progress in fiber developement: LYSO:Ce

Comparison of the different fibers Development of the fiber quality and the rectangular LYSO:Ce rods new calorimeter concepts

dual readout / new sampling concepts

LuAG

K. Pauwels et al. SCINT 2013 homogeneity:

LuAG and Cu similar density