1. TIMING COUNTER: status report Giorgio CECCHET, PSI July 11th, 2003

2. Timing counter MC activities Tests on PM characteristics Preliminary results of May test Tests in magnetic field Possible new ideas on “transverse counter”

3. Montecarlo activities Reorganization of code repository Critical revision of TC code Rievaluation of main geometrical parameters of TC

4. Length 70 cm Angle (-140,10)° Radius 28.2 0.5 29.0 2.0

5. Tests on PM characteristics Basic tests on gain and TTS Photomultiplier used Hamamatsu fine mesh 1,5”, 19 dynodes H8409-70mod

9. MMICRO CHANNEL PLATE PMT Serial n.Q.E. % (500nm) V MCP (10^6) Noise (0.5 p.e.) 325619,22450V100kHz 723718,52160V140kHz Active diameter:20 mm Test wavelength 670 nm Ligh spot diameter8 mm

12. May 2003 test On May 2003 two scintillators (80x5x1) assembled with 1.5” and 2” PM’s and taken to  E5 area Aim: measure rough count rate in conditions similar to final

16. Main results Position similar to final in the Cobra (30 cm off beam axis) Rates: Beam off -> Bck: 25evs/s Beam on, no mu stopper -> 0.5 Mhz Beam on, with mu stopper -> 5 Mhz PMT saturation: 25Hz->10KHz : 1.8 V/pulse 20KHz: 1.7V/pulse 200KHz: 0.4 V/ pulse PMT with higher anode current are nedeed (2” PM better than 1.5”) Need to design a higher current voltage divider?

17. With collimated beam (10 mm dia.): measure of arrival time differences between 2 PMTs and calculation of time resolution FWHM using the formula: Sigma*2.35/sqrt(2) We obtain 175 ps FWHM for the single PMT, in absence of magnetic field.

18. Magnetic field tests One week ago magfield tests started Conventional magnet in LASA (Milan) with 12 cm headroom and field up to 1.2 Tesla water cooled

21. Setup used A very simple setup was used to take the light from a blue diode to the photocathode

26. New ideas Investigate the possibility of using a 5x5 mm2 APD from Hamamatsu to readout optical fibers as transverse (trigger) counter. Few samples made available from PSI and under investigation in Genoa

29. More work to be done Complete timing test on single PM in magnetic field Test scintillator coupled to PM’s in magfield (MARISA) Full testing of APD’s and optical fibers Exploit the full capabilities of fine mesh PM’s (new voltage divider?....) Engineering test of 3-4 scintillators and similar number of fibers during Oct-Nov beam time

30. Rotable support for 1-2 PMT/MCP for MARISA magnet under construction. B= 0-1.6 T Measurement of single PMT parameters (gain/TTS vs B) at different angles with B 2-PMTs and scintillators assembly. B field measurements: planned form july 15 to 30

31. Not to mention work going on Helium bag!

32. Schedule We think now we do not have yet enough infos to make a correct choice of the PM to be used in the TC. We are confident that the new tests will lend us to a reliable decision.

33. 2002200320042005 Test Milestone AssemblyDesignManufactoring Design PMT EvaluationPMT