1. Anatoly Ronzhin, 23 June, 2009 Anatoly Ronzhin, June 23, 2009 The main results of the TOF study at MT beams, May-June 2009 The team: Anatoly Ronzhin, Hans Wenzel, Erik Ramberg, Mike Albrow, Sasha Pronko, Fermilab Andriy Zatserklyaniy, University of Puerto Rico Andriy, Sasha and Hans are the new member of our picosecond test beam community (“picoclub”).

2. Anatoly Ronzhin, 23 June, 2009 SiDet preparation before the test beam Most of the “pico” test beam equipment: dark boxes with Faraday cages, trigger and veto counters, MPPCs assembly, MCP PMT micrometric supports, tubes supports, alignment were prepared and tested at SiDet. Main timing parameters of all photodetectors (SiPms, MCP PMTs Photonis, 240, 210 Photek, response vs HV) obtained with PiLas laser. Good consistency with test beam data. During the tb used as perfect reference. Power supplies (HV, LV), SMA: splitters, attenuators, cables were tested before test beam. Frontend, including Ortec 9327, VT120 preamps, S. Los amplifiers, TACs. DAQ was prepared, tested (including AD114 readout). This allowed to complete our program in timely fashion. Plan of strategy for the test beam was carefully prepared

3. Anatoly Ronzhin, 23 June, 2009 Frontend, readout prep at SiDet Extensive study of VT120, 9327, SMA: att., cables, splitters, (including cable length influence on the time resolution) before the TB. E.g., it was found that 14 meters of cables length of the 9327 NIM out does not worsen “electrical” time resolution, still the same (about 1ch=3.1ps). This allowed to locate NIM and CAMAC crates in the TB control room w/o resolution deterioration. Extensive study of TAC 566 plus AD 114. Influence of SiPms clipping on the time resolution.

4. Anatoly Ronzhin, 23 June, 2009 World’s Best Beamline Time-of-Flight System? MT TOF. Base distance (B) between start and stop counters 8.7meters, time resolution 24 picoseconds (sigma) for positrons. Proton peak position given by arrow. Stop - Photek 240, normal to window particle’s incidence, window thickness – 9 mm of fused silica. Start – two quartz bars at Cherenkov angle, each viewed by Photek 210 MCP PMTs. The obtained time resolution could be improved with use, e.g., Photonics MCP PMT as start counter (our previous test beam data). Proton peak position marked by arrow Beam time resolution 24ps

5. Anatoly Ronzhin, 23 June, 2009 For memory Note: TOF based on Cherenkov radiators has momentum threshold Photek 240 “downstream” MT TOF counter perfectly fits to “normal” particles incidence with packaging “Upstream” TOF counter should be as “thin as possible”. Inverse “square root” dependence of the time resolution vs number photoelectrons is true for fixed light pulse shape. Not necessarily true for Cherenkov TOF application. The number of photoelectron increased partially due to increase of a pulse duration in the case. H.Wenzel, E.Wilson Hans Wenzel plot

6. Anatoly Ronzhin, 23 June, 2009 Photek 240, from specs. 9 mm thickness, 40 mm diameter fused silica input window. Tb - 7 phes/1 mm. 10/12 um pore TTS – 100 ps, HV? Cost reduction?

7. Anatoly Ronzhin, 23 June, 2009 Photek 240, currently “best”. 5-7 ps - “time jitter with 60-70 photoelectrons” obtained for the 240 on the beam. The level is require to explore exact deposit of “electrical time resolution”, “frontend jitter” into the value. Andriy is working on convolution of the Vavilov- Cherenkov light, 240 QE, quartz transparency to explain 7phes/1mm of “fused silica” 240 window. Next SiDet plan: timing uniformity along PC, SPTR dependence on HV. With PiLas, Ortec. More study of electrical time resolution deposit.

8. Anatoly Ronzhin, 23 June, 2009 Photek 210 “response vs. HV”, 210, 240 signals on TB Ch1-trigger Ch2-Photek 210, 1, 9327 analog out Ch3-Photek 210, 2, 9327 analog out Ch4-Photek 240, 9327 analog out Ch1-trigger Ch2-trigger plus VETO Ch3-Photek 210 signal for PH analysis Ch4-Photek 240 signal for PH analysis SiDet setup for 240, 210 study TTS – 30 ps, HV?

9. Anatoly Ronzhin, 23 June, 2009 Some of the MPPCs results obtained at SiDet and MT, time resolution, sigma 35 ps, best? 35ps/MPPC Ch1-trigger Ch2-MPPC 1 9327 analog out Ch3-MPPC 2 9327 analog out Ch4-Photek 240 9327 analog out MPPC’s SPTR dependences on overvoltage Time resolution vs 9327 input amplitude 35ps/MPPC, test beam data

10. Anatoly Ronzhin, 23 June, 2009 Also tested at TB Normal incidence, Photek 210Qbars, viewed by Photek 210 Qbar, viewed by 2 Photek 210 Aerogel Cher. counter

11. Anatoly Ronzhin, 23 June, 2009 1.48x48 mm2 total sensitive area, 6x6 mm2 of the one channel size. Quartz radiator 50x50 mm2, 5 mm of thickness, covered the all MCP sensitive area, optical contact between the MCPs and quartz radiator, the MCP’s 2 mm thick input window. Sergey Los CB prototype of “active SUM” of the 64 channels. 2. Obtained about 30 ps per MCP. The time resolution is mostly due to larger capacitance, if to compare with the MCP “passive readout”. We got 14 ps time resolution for the same MCP with 2x2 chs “passive readout” on the Aug. 2008 test beam. 3.Plans. In the beamline application the upstream TOF counter should be as “thin as possible” and downstream counter’s thickness not so important (ECAL, HCAL, muon, behind). In the current state it’s possible to use MCP PMT as “start counter”. S.Los continue to investigate “passive readout”. 64 chs, 8x8 MCP PMTs, Fermilab Test Beam Results

12. Anatoly Ronzhin, 23 June, 2009 Equations for sigma calculations Copy from beam elog. We had three detectors in beamline, I, II, III. Suppose the "intrinsic time resolution" of the detectors are I, II, III. (sigma of Gauss fit, for each of them). The measured values are T12, T13, T23 (sigma of Gauss for each of them, after all possible corrections). We neglect "electrical time resolution" of the readout, our SiDet and previous tb data shows up about 2-4 ps. We easy have 3 equations with 3 variables. I^2 + II^2 = T12^2 (1) I^2 + III^2 = T13^2 (2) II^2 + III^2 = T23^2 (3) unfolding, e.g. III from the 3 equations, we have III = sqrt (T13^2 + T23^2 - T12^2)/sqrt 2, I = sqrt (T12^2 + T13^2 - T23^2)/sqrt 2, II = sqrt (T12^2 + T23^2 - T13^2)/sqrt 2, Returned back to the setup with 2 Qbars and Photek 240. Both 1-3 and 2-3 combination gives us 10-11 channels of the time resolution, same as yesterday. Tomorrow will move Photek 240 downstream, about 10 meters. Both Qbars, (1 and 2) will stay in the dark box in current position. We can improve our total time resolution by factor of 1.4 by measuring time of flight twice (1-3 and 2-3), so the final time resolution should be about 7-8 channels or 22-25 ps (for positron only, for other particles will be dependent on the momentum spread). Sum 1-3 and 2-3 will “kill” time jitter due to the beam size. It should be good to arrange histo for 1-3 plus 2-3, event by event, devided by 2 for that. It would be also good to have in hands table with the time of flight difference for positrons, muons, pions and protons (for 4, 3, 2, 1 GeV of the momentum) and 1 meter of the base distance to be prepared for the tomorrow exercises. Histos and table done by Andriy and Sasha, thanks Anatoly

13. Anatoly Ronzhin, 23 June, 2009 Preliminary Summary 24 ps, sigma, obtained for MT TOF system 5-7 ps, sigma, Photek 240, for particles with “normal incidence”, (beta=1) 12 ps – Photek 210 17 ps – double Qbars 35 ps, – for MCCPs 33.5 ps – for aerogel The analysis is not completed, continued

14. Anatoly Ronzhin, 23 June, 2009 TABLE with time resolution and number of photoelectrons of the tested photodetectors