1 TRD-prototype test at KEK-FTBL 11/29/07~12/6 Univ. of Tsukuba Hiroki Yokoyama The TRD prototype is...
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Transcript of 1 TRD-prototype test at KEK-FTBL 11/29/07~12/6 Univ. of Tsukuba Hiroki Yokoyama The TRD prototype is...
1
TRD-prototype testat KEK-FTBL
11/29/07~12/6
Univ. of TsukubaHiroki Yokoyama
The TRD prototype is borrowed from GSI group (thanks Anton).
KEK-FTBL
• KEK, Fuji Test Beam Line• 2007/11/29-12/6• 3GeV/c,electron beam
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Beam Area
TRD-prototype
3
4
setup
Scintillation CounterTRD MRPC PbGlass
Trig for TOF
measurement• Pad Response Function• Amplification of signals (through anode voltage and
gas dependence)• Electron attachment (through drift voltage
dependence)• Drift velocity (through drift voltage and gas
dependence)• Absorption of TR-photon ( absorption length in
2type gases, Ar+CO2(85,15),Xe+CO2(85,15))• Angle dependence of position resolution
Pad Response Function
• distance from CM vs. proportion of induced charge to sum of them.• Full width of signal sharing in azimuthal direction is 3pads.
6Pulse height is defined as sum of three adjacent pad’s induced charges.
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Gas GainAr+CO2(85,15) Xe+CO2(85,15) Drift Voltage
-2100VAnode Voltage
1500V1450V1400V1350V1300V
Gas gain by avalanche can be fitted by exponential
function of anode voltagePul
se h
eigh
t at
Am
p re
gion
Me
an
pu
lse
he
igh
t
time time
Anode voltage
Anode voltage vs pulse height
Ar+CO2(85,15)Xe+CO2(85,15)
Mea
n pu
lse
heig
ht
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Drift velocity Anode Voltage
1500VDrift Voltage
-2100V-2000V-1900V-1800V-1700V
Drift velocity for Ar gas is about three times larger than that for Xe gasD
rift
Ve
loci
ty
Electric Field of Drift region
Electric field vs Drift velocity
Ar+CO2(85,15)Xe+CO2(85,15)
time time
Ar+CO2(85,15) Xe+CO2(85,15)
Me
an
pu
lse
he
igh
t
Me
an
pu
lse
he
igh
t
Electron attachment
9The attenuation of signal by H2O or oxygen depends on time that
electrons stay in the chamber.
Attenuation of signal by electron attachment
a/b is defined as sign of electron attachment.
a
b
Stay time of electron
a/b
Ar+CO2(85,15)Xe+CO2(85,15)
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Anode Voltage1500V
Drift Voltage-2100V
With RadiatorWithout Radiator
before after
before after
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TR-photon signal(1)•Correct time distribution to be flat shape in the drift region
time
time time
time
Ar+CO2(85,15)
Xe+CO2(85,15)
TR-photon attachment
Depth of detector from drift electrode(mm)
Ar+CO2(85,15)Xe+CO2(85,15)
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TR-photon signal(2)
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Depth of TRD-prototype is 30mm.95%(in Xe),28%(in Ar) TR-photon energy is absorbed.
•Calculate the TR photon contribution as the difference between time distributions with/without radiator.•By slope of exponential fit, I calculated absorption length of TR-photon in each gas.
absorption length
€
λ =89mm(in Ar)
10mm(in Xe)
⎧ ⎨ ⎩
⎫ ⎬ ⎭
resolution in azumuthal direction
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Data for fit
Calculate center
1pad(=8mm)
Resolution(angle 0°)is about 400μm12
Pad number
Measure difference between this point and fited line
Angle=20°
angle resolution
0° 391±10μm
10° 605±28μm
20° 1071±22μm
30° 1614±45μm
time time
Pad
nu
mbe
r
summary• Signal share is less than 3 pads.• Gas gain by avalanche can be fitted by
exponential function of anode voltage.• Drift velocity in Ar gas is about three times
larger than that in Xe gas.• The attenuation of signal by hydrogen and
oxygen depends on time that electrons stay in the chamber.
• absorption length in Xe(Ar) is 10mm(89mm)• Resolution(angle 0°) is 391μm.
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