Test%20results%20and%20status%20on%20T0

1
Test results and status on T0

• T0 start counter for pp collisions

ShinIchi Esumi Inst. of Physics, Univ. of Tsukuba

test experiment at KEK-PS analysis results and
simulations photon conversion rejection Summary,
open questions and plan
2
Proposed
T0 in PHENIX
T0
TOF
Hiroshi Tsuruoka, Masaya Ono
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Test experiment at KEK-PS

• time resolution
• position dep.
• thickness dep.
• width dep.
• light guide
• B-field dep.

2GeV/c pi- beam
start1
start2
veto
define1
conv. rej.
T0
B-field
Fine mesh PMT Hamamatsu 2inch R5924
define2
4

5
Time resolution
Slewing correction
ST1-ST2
T0 59ps ST1 39ps ST2 31ps
TDC
ST1-T0
ST2-T0
ADC
(T0R-T0L)/2
beam width (def. size) 1cm/15cm/ns/sqrt(12)
20ps
s(T0) 59ps
Yoshiaki Kuroki, Masaya Ono
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HV/position dependence
Masaya Ono, Hiroshi Tsuruoka
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Thickness/width/light guide dependence
Masaya Ono, Hiroshi Tsuruoka
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B-field dependence
Masaya Ono, Hiroshi Tsuruoka
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Simulation
with GEANT/pisa reconstruction
s(dP/P)
with T0
T0 (thickness 1.5cm)
without T0
no mult. scatt.

• momentum resolution

momentum (GeV/c)
Akio Kiyomichi, Miwako Suzuki, Ayako Danmura
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Photon conversion rejector
p
e
e
e
TEC/TOF

• thin scintillator in front of T0
• to reject photon conversion at T0
• high efficiency and low BG

RICH
DC/PC
T0
PCR
g
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Test setup
Plastic Scintillator (BC 404,BC408)
WLS-fiber(BCF-92)
pedestal
13 photons
Ayako Danmura
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Comparison with simulation
dEdx from GEANT ltNpegt from experiment Poisson
statistics count efficiency with Npe threshold
1
0.0 0.2 0.4
Ayako Danmura
13
Signal/noise for F to ee
Noise
S2/N
Signal
Thickness (cm)
S2/(2NS)
NN/10
NN/100
Thickness (cm)
Ayako Danmura
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Mechanical design
Hiroshi Tsuruoka
15
Summary

• Time resolution about 60ps
• It does not depend on position nor B-field
• Fine mesh 2inch PMT (R5924) x25 ordered
• 1.5x8x100(cm3) and 10cm light guide x8 slats
• Readout electronics (8ch x 3) from BBC

Open questions

• Photon conversion rejector option? (read-out)
• Removable T0 only for hadron PID run?

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Schedule
fine mesh 2inch PMT (R5924) x25 ordered PMT
delivery scintillator and light guide
order mechanical structure design and
order shipping all the materials to BNL assembly
installation after heavy ion run one week access
to complete
2001.1
2001.3
2001.4
2001.6
2001.8