1. PMT SPE Measurement @ Chiba (new parameters for next version of ROMEO) (new parameters for next version of ROMEO) Yusuke Hasegawa et al., presented by Hiroko Miyamoto & Kotoyo Hoshina Dept. of Physics, CHIBA University and UW Madison

2. SPE response for ROMEO Make Model of Charge Response function for the PMT simulation (ROMEO). Fitting Function? Fitting parameters? Examine SPE waveform. Tube to Tube Variance of Pulse Width

3. Electronics of Charge Response 70nse c CAMAC Crate Controller Crate Controller ADC GP-IB Function Generator Function Generator NIM PCI Card CAMAC Interface CAMAC Interface GP-IB Interface GP-IB Interface Gate Generator Gate Generator LinuxPC Sync. PMT Freezer(-32 ℃ ) Gate Signal Discriminator TTL-NIM Converter TTL-NIM Converter 2kHz, ~ 0.01 photo- electron/shot 4 ~ 6nse c 375 nm UV LED diffus er ~ 100ns

5. PMT Setting in the Freezer Base circuit Diffuser attached to UV LED

6. The parameterization of PMT SPE charge response  Fitted the spe charge response with 1 exponential + 1 gaussian terms.  The exponential term comes from a incomplete multiplication at a dynode.  Integration from qped to infinity is 1(normalized) 2 ()

7. Charge Response @ different gains @1x10 7 @5x10 7 @1x10 8 TA1052 (GPMT)

8. The obtained parameters  total 118 PMTs (FY 2004 ~ 2006)  Many PMTs failed to fit at low gain Summarized by Y. Hasegawa sq0/q0qtau/q0 p_ex http://www.ppl.phys.chiba-u.jp /research/IceCube/pmt/SPE/CRAnalysis.html TA2086 (current ROMEO)

9. The averaged charge response for each gain gain=5x10 7 gain=12x10 7 gain=8x10 7 PMT to PMT difference is larger than the gain dependence! qtau/q0 p_ex sq0/q0 qt/q0:0.42, sq0/q0:0.27 p_ex:0.36 qt/q0:0.50, sq0/q0:0.30 p_ex:0.29 qt/q0:0.51, sq0/q0:0.29 p_ex:0.32

10. The all averaged charge response All averaged charge response (gain >5x10 7 ) Current ROMEO (TA2086)  Averaged charge response is now close to J.Kelley’s measurement  ~ 10% of P.E. are below threshold (0.2 p.e.) p.e. sq0/q0qtau/q0p_exIntegral <0.2p.e. averaged0.28250.49350.2969 9.73% ROMEO0.36500.12190.276523.09% Arbitrary unit

11. Electronics of Waveform Taking 75nsec GP-IB Oscilloscope CH2 CH1 Oscilloscope CH2 CH1 GP-IB Function Generator Function Generator NIM Divider Discriminator Gate Generator Gate Generator Coincidence PCI Board GP-IB Interface GP-IB Interface Gate Generator Gate Generator LinuxPC TTL-NIM Converter TTL-NIM Converter Sync. PMT Freezer(-32 ℃ ) Trigger Signal Discriminator Level : 10 [mV] @ 5x10 7 Gain ( ~ 0.4 p.e.) 2kHz, ~ 0.01 photo- electron/shot diffus er 375 nm UV LED 1,000 samples/measurement

12. SPE Waveform pulse Gaussian Fit [ns] [mV]

13. SPE Waveform width FY2004 ~ FY2007 2004200520062007

14. SPE Waveform width FY2004 ~ FY2007 total Average: 2.192 Current Romeo: 2.18659

15. 2.192 2.455 2.113 Current Romeo: 2.18659 SPE Waveform width FY2004 ~ FY2007

16. Summary Averaged charge response and waveform width over 100 PMTs are calculated, ready to be implemented into the new version of ROMEO. Averaged charge response is now close to J.Kelley’s DOM measurement. ~10% of P.E. are below threshold (0.2 p.e.) Waveform width shows some significant change at around the end of FY2006. -> Study will be continued..

17. END

18. Module NameModelCompanyNotes Function Generator33120AAgilent Technology OscilloscopeTDS2012Tektronix2ch, digital strage ADC (Analog to Digital Converter) 2249ALeCroy0.25pC/bin, full scale, 256pC(1024ch) Crate controllerCC/7700Toyo technica Dual gate generatorKN1500Kaizu Works 8ch DiscriminatorN-TM405Technoland 4-hold 1- veto coincidence 470Kaizu Works Quad High VoltageRPH-22Repic 16ch TTL-NIM Level Adopter KN206Kaizu Works Preset scaler controller150Kaizu Works Dual variable delay330Kaizu Works Nichia UV LEDNSHU550ANichia375nm, 220Ω driving Measurement Setup - Module