1 / 14

PMT Test @ Univ. of Tokyo

PMT Test @ Univ. of Tokyo. Yasuko HISAMATSU. ICEPP,. MEG Collaboration meeting Feb. 10th, 2004. PMT Output Deterioration. During the pi0 beam test @PSI, output from some PMTs reduced by 20-30% when beam was ON. (The background was estimated to be ~ 1.5*10^6p.e. per sec)

Download Presentation

PMT Test @ Univ. of Tokyo

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. PMT Test @ Univ. of Tokyo Yasuko HISAMATSU ICEPP, MEGCollaboration meeting Feb. 10th, 2004

  2. PMT Output Deterioration • During the pi0 beam test @PSI, output from some PMTs reduced by 20-30% when beam was ON. (The background was estimated to be ~ 1.5*10^6p.e. per sec) • Similar change was observed under the background simulated using LED pulses -> The Deterioration of old type PMT output due to the high rate background. • Output from Al Strip Type PMT (new type) needs to be tested under the high rate background, 10^6 ~ 10^8 p.e. per sec . Yasuko HISAMATSU MEG Collaboration Meeting @ PSI February 2004

  3. PMT Test @ Univ. of Tokyo PMT (Al Strip Type) TB0094 TB0102 TB0239 TB0268 TB0284 TB0302 TB0415 TB0439 TB0568 • Set up Liq. Xe PMT 5.5MeV alpha peak Alpha source(241Am ) LED PMT ADC channel Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

  4. PMT Test facility @Univ. of Tokyo Purification system Chamber Inside alpha source LED Xe tank Liq.Xe chamber PMT

  5. Condition and Procedure • alpha source : ~200Hz, • LED pulse height: 500p.e. ~ 12000p.e. per event pulse shape: ~10nsec rate: 100Hz ~ 10KHz • Trigger: alpha self trigger (veto by LED driver pulse) • Procedure • Pedestal Run & Gain calibration using LED • Alpha Run @ LED OFF • Alpha Run @ LED ON (LED : high rate background) • -Change LED Pulse height, rate and PMT gain Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

  6. Condition and Procedure • DAQ: -Alpha run with LED OFF -Alpha run with LED ON • The cause of the change in PMT output • Breeder current ? • Deterioration of photocathode? The change in PMT output? Low gain run Peak/Sigma (gain independent) Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

  7. Thermal neutron background estimation • Condition of the estimation • 16 n/cm^2/sec (MEG TN022) • From all direction • 6*10^5 photons ( : ~9MeV gamma ) are generated in LP MC 5.2 * 10^6 p.e. /PMT/sec @LP • Scaled to the final detector (surface area) 3.2 * 10^7 p.e./PMT/sec @final detector = 5.0 *10^-6 A @10^6gain PMTs were tested under the background of 10^6 ~ 10^8 p.e./sec

  8. For instance…TB0415 5*e^5 gain peak (LED ON)/peak (LED OFF) 1*e^6 gain peak (LED ON)/peak (LED OFF) 10^7p.e. per sec 1*e^6 gain (peak/sigma @LED ON)/ (peak/sigma @LED OFF)

  9. Result X: number of photoelectrons per second from LED Y: alpha peak (@LED ON) / alpha peak (@LED OFF) TB0094 TB0302 TB0568 TB0102 TB0284 TB0439 5*e5gain TB0268 TB0415 TB0239 Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

  10. Result X: number of photoelectrons per second from LED Y: alpha peak (@LED ON) / alpha peak (@LED OFF) 1*e6gain TB0094 TB0302 TB0568 TB0102 TB0284 TB0439 TB0268 TB0415 TB0239 Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

  11. Result X: number of photoelectrons per second from LED Y: (peak/sigma @LED ON) / (peak/sigma @LED OFF) 5*e5gain TB0094 TB0302 TB0568 TB0102 TB0284 TB0439 TB0268 TB0415 TB0239 Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

  12. Result X: number of photoelectrons per second from LED Y: (peak/sigma @LED ON) / (peak/sigma @LED OFF) 1*e6gain TB0094 TB0302 TB0568 TB0439 TB0102 TB0284 TB0268 TB0415 TB0239 Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

  13. X: event number Y: ADC count PMT Output vs Elapsed Time TB0239 1*10^6gain Background 1.33*10^8pe/sec 5*10^5gain Background: 8.32*10^7pe/sec ~10sec ~20sec • DAQ started 2 ~ 10 sec after the LED had been turned on. • Stable output up to 5*10^7 photoelectrons/sec Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

  14. Summary • 9 Al Strip Type PMTs (new type) have been tested under the high rate background environment at the university of Tokyo. • So far, for the 9 PMTs, the stability of PMT output is better than 10% under the background up to 10^7 p.e. per sec. • For the 8 PMTs out of 9 PMTs, no output deterioration under background of ~1.5*10^6p.e. per sec. • For a PMT, TB0239, the output deterioration due to the breeder circuit was found under the background of ~1.9 * 10 ^6p.e. per sec. • The background number of photoelectrons should be suppressed to 10*6 p.e./sec. • Necessary to suppress thermal neutrons to 1/10. • Neutron background measurements @piE5 using LP is recommended. Yasuko HISAMATSU MEG Collaboration Meeting @PSI February 2004

More Related