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KEK Test Beam Phase I (May 2005)

KEK Test Beam Phase I (May 2005). Makoto Yoshida Osaka Univ. MICE-FT workshop @ Daresbury Aug 30th, 2005. Contents. KEK beam test (KEK-PS T571) Equipments Setup TOF hodoscopes Timing resolution Operation in magnetic field Aerogel Cherenkov Counter (ACC)

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KEK Test Beam Phase I (May 2005)

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  1. KEK Test BeamPhase I (May 2005) Makoto Yoshida Osaka Univ. MICE-FT workshop @ Daresbury Aug 30th, 2005

  2. Contents • KEK beam test (KEK-PS T571) • Equipments • Setup • TOF hodoscopes • Timing resolution • Operation in magnetic field • Aerogel Cherenkov Counter (ACC) • Response for pions, muons and electrons • Beam survey • Focusing magnets • Lead diffuser • muon rate in low momentum beam

  3. KEK-PS T571 • May 26th– June 2nd at KEK-PS p2 beam line • Super-conducting solenoid • 1T magnetic field • 40cm x 40cm TOF hodoscopes • p/m separation by TOF • Momentum measurement for low momentum particles • Aerogel Cherenkov counter • Refractive index : 1.05 • Discriminate p/m/e by light yield in combination with TOF

  4. Q3 Q4 D4 Setup T1 2cm-thick scintillator Aerogel Diffuser Defining Counters TOF hodoscope

  5. Super conducting solenoid 1Tesla Magnetic field φ８５０mm Side view length 1.3m Super-JACEE for balloon experiment Front view

  6. Fine mesh PMT R6504S ,19DY Shape of TOF using guide7 Long light guide Magnetic field is not parallel to PMT axis Could cause spoil of PMT gain Momentum for beam test 300 – 600 MeV/c Particle identification 3sp/m separation @600MeV/c sTOF < 230 ps Up stream : 50ps Down stream （hodoscope) : 50ps Downstream TOF Counter TOF hodoscope

  7. Defining counter / TOF hodoscope TOF 1  5 TOF 6  10 Defining counter inside solenoid 5x5 TOF hodoscope

  8. Test for TOF performance • Calibrate TOF counters in 40cm x 40cm large area • upstream TOF counter s~40ps • Diffuser (5cm-t lead block) • Negative 3GeV/c (p-) • Solenoid ON/OFF Finger counter 5cm lead block T1 ~30cm ~900cm TOF hodoscope

  9. 3Gev/c p- w/o magnetic field s(TOF8-T1)=77.3ps s(T1)=41.8ps s(TOF8)=65.0ps Timing resolution of TOF hodoscope -400ps 400ps TOF8-T1

  10. Timing resolutionin fringing magnetic field No significant loss of timing resolution in magnetic field

  11. w/o magnetic field s(hodoscope)=53.6ps w/ magnetic field s(TOFhodoscope)=53.0ps Timing resolution of hodoscope σ＝68.0ps σ＝67.5ps (Average of horizontal and vertical TOF counters) -T1

  12. Position dependence of TOF resolution • w/o magnetic field • w/ magnetic field No significant position dependence : 50ps-60ps

  13. Improvement of Aerogel • Development of ACC used for redandunt PID of e,m,p in SciFi tracker test. • Aerogel in Feb. 2005 • refractive index n=1.03 • Effective momentum range : 426 - 565MeV/c • Npe was measured to be 18 p.e for electrons. • New Aerogel • Adapt to low momentum m beam • The Aerogel (index = 1.05) was selected in May,2005. • m PID in the range of 328 - 434MeV/c is possible. • Furthermore the Aerogel have some advantage. It is new type Aerogel developed by Matsushita Electric Works, Ltd. and improved on transparency (over 90%).

  14. ACC performance 0.425GeV/c Negative e- m- p-

  15. ACC light yield • Fit left edge of ADC distribution with Gaussian • tail on the right cannot be described by Poisson distribution • tail could be caused by after-pulse in Fine-Mesh PMT • need to select proper gate width • Light yield of ACC = 32 p.e. • ADC mean = 46.8 • ADC sigma = 8.3 • (46.8/8.3)2 = 32 p.e. • Performance is improved significantly • Feb. 2005: 18 p.e. (n=1.03) • May 2005: 32 p.e. (n=1.05)

  16. (1.051)2 Cross check for ACC light yield • Npe is proportional to 1-1/(b2n2) • Npe = 0  n2=1/b2 • Scan beam momentum from 325 MeV/c to 450 MeV/c • Measured refractive index of the ACC is 1.051 • Our calculation in the previous slide is confirmed to be valid 1/b2

  17. Defining counter efficiency 40cm x 40cm 24cm x 24cm Good efficiency e > 99%

  18. Q3 Q4 D4 Focusing study Q3=83 Q4=73 Q3=68 Q4=52 Q3=117 Q4=161 sx=11.6 sy=11.0 sx= 11.5 sy= 10.8 sx=11.9 sy=11.3 Modification on focusing magnet current for 0.3GeV/c beam does not affect on beam profile so much

  19. Diffuser study -0.3GeV/c Beam divergence w/o solenoid increase to ~20cm/200cm=100mrad @15mmPb

  20. Muon yield in low momentum beam -0.3GeV/c 5475 m / 16min =6Hz e- p- m- -0.4GeV/c 9000 m / 10min =15Hz

  21. Summary • Beam test with SC solenoid was performed at KEK-PS p2 beam line during May 26th– June 2nd • TOF performance was checked in magnetic field • Intrinsic resolution of the counter better then 70ps • Resolution of the TOF hodoscope (average of horizontal & vertical) ~ 50-60ps • ACC (refractive index = 1.05) was tested • good performance to discriminate p/m/e at 0.425GeV/c • Beam parameter was surveyed to be optimized for Autumn beam test • The effect of lead diffuser was measured, will be compared with simulations.

  22. TOF measurement by VME TDC • CAEN V1290 • 25ps resolution • 16 LEMO inputs • multi-hit/multi-event buffer (32k x 32 bit) +1GeV/c TOF at center S=150ps S=180ps w/o timewalk correction

  23. VME ADC .vs. TDC • CAEN V792 • 12bit resolution • 32 inputs with 2 flat connectors • multi-event buffer (32 events) TOF2A TOF2B Something mis-configuration on the ADC module for TOF counters

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