YPWO

1
Y?????????????(PWO)??????????????
Performance of a EM calorimeter of Y-doped
Lead-Tungustate Crystals
Contents motivationPWO crystalBeam test
150MeV electron beam Energy resolutionAPD
readout Summary and outlook
?58????? ???? ??????? ????,????,????,???, ????,??
??,????,???? (????????????????)
2
Motivation

• A large amount of particles is produced in ultra
  relativistic heavy ion collisions in a unit solid
  angle.
• We need high energy resolution and high
  granularity electromagnetic calorimeter.
• Lead-Tungstate (PWO) calorimeteris the best
  candidate.
• At previous JPS, Furuhashi reporteda property of
  single PWO crystal.
• New Progress
• Energy resolution of 3x3 PWO arrayreadout by
  PMT.
• Readout by APD only forthe central PWO of the
  array.

From ParticleDataGroup
3
PWO crystal dense, fast and radiation-hard
scintillator
Y-doped PbWO4 Density 8.28 g/cm3 Radiation
length 0.89 cm Moliere radius 2.2 cm Peak
emission 420440 ns Refractive index 2.3
Furukawa Co.
20mm20mm200mm 22 radiation length 0.9 moliere
radius
transmittance
with Spectrophotometer Hitachi U3010

• Slightly yellowish due to the absorption bands
  in the blue region of lead oxide
• Internal absorption length 56 cm at 420 nm

4
Beam test _at_ REFERRelativistic Electrons
Facility for Education and Research
REFER ring
No RF 150MeV electrons 10Hz
trigger signal PWO signal ring current
circulation
Extraction 500?
injection
5
Beam test _at_ REFERRelativistic Electrons
Facility for Education and Research
Top View
Slide table
3x3 PWO PMT
150MeV e-
Trigger counter
collimator
Lab. Jack
Side View
6
Beam test _at_ REFERCalibrations for each PMT with
150MeV electron
Single PWOPMT ADC histogram
Single electron s/E 10
Ee 117 MeV s/E 13
Double electron
Inject electron into each 9 PWOPMTs for
calibration
GEANT4 simulation
Typical PMT output Average count rate a few
kHz Extraction time 500us 10Hz
Count rate 106Hz
7
9 PWO Energy resolutionSumming up of 9 PWOPMT
output
Peak 145MeV s/E 8.3
Summing Up
s/E 10
97 of the incident energy was deposited. Energy
resolution of 8.3 at 150MeV (include beam energy
fluctuation)
s/E 3.2/vE ( Ref. Particle Data Group 3 /vE )
8
APD readoutReplace a PMT at the central crystal
with APD

• Readout by APD only for the central PWO.
• HamamatsuAPD S8664-55HamamatsuPreAmp H4083 NSC
  LM6172

5mm5mm
Gate for Peak sensing ADC (Hoshin C008H) Neighbor
PMTs APDAMP output (100mV 3us)
9
APD result
s/E15
Summing Up
s/E18
Succeed readout PWO photons by APDP.S.ADC Need
to reduce noises to improve s/E Optimize the
pre-amplifier design for APD
10
SimulationA Monte Carlo simulation of the PWO
photon spectrometer
10 ?0 s in the acceptance (dN/d?76) d?/dp?exp(-p
/0.3) (1ltplt5 GeV/c) flat distribution in y and ?
GEANT4 Simulation
The Photon Spectrometer coverage 1m 1 m crystal
size 2020200 mm3 array size 50 50 distance
from IP 3 m ? coverage ?0.17
Deposit Energy vs. Hit Position at the PWO
Spectrometer
11
Summary and outlook

• ltSummarygt
• s/E 3.2/vEGeV
• E/Eincident 97
• Succeed readout PWO photons by APD.
• ltoutlookgt
• A new pre-amplifier for APD is under building.
• Another beam tests at Tohoku-LNS is planned .

12
Scintillating propertiesmeasurements of Light
Yield Decay Time
Temperature chamber -40?100? ESPEC PU-1K
room temperature
13
Scintillating propertiestemperature dependence
Light Yield
Mean decay time
14
Beam test _at_ KEK-PSPWO calorimeter test in T496
p2 beam line unseparated beam 1 GeV/c 3 GeV/c
proton , pion or electron
15
Beam test _at_ KEK-PSPWO calorimeter results
electron
Deposit energy distribution PWO(B)PMT(Hamamatsu
R7056)
Results Single PWO crystal 5.4/vE(GeV)
experiment 4.6/vE(GeV) simulation 9 PWO
crystals in a 33 matrix 2.1/vE(GeV) expectation