PSD news, plans

1. PSD news, plans F.Guber, A.Ivashkin INR, Moscow • Status of the PSD calibration • Plan of construction of the 12 last modules • Discussion of beam position of the PSD at nearest ion run • Status of A-detector and test run at T10 (26 Sep- 10 Oct)

2. Status of the PSD calibration • -Calibration start at 2 September; • -16 small + 16 large modules have been calibrated at 3 sets of MAPDs voltages • with 158 GeV beam (~50% protons +50% pions), No muons in the beam! • Count rate ~2x105 per spill; DAQ rate – 104 per spill. • At present, energy resolution measurements with pure proton trigger are ongoing; • After that measurement of homogeneity energy resolution across the PSD wii be done; • - In parallel, Marina treat the data to extract calibration parameters and energy resol.

3. Problems during the calibration • Platform remote control is not working! We use video camera to install the PSD. • Drawbacks – can not be install better than +/- 1cm. Simulation have been done • for point like beam at the center of module. -It was found that noise level for 24 modules for one Wiener LV PS is few times less than for another 6 modules with second Wiener PS. Problem was solved yesterday by separate LV PS at opposite crate slots. Now level of noise is acceptablefor both Wiener PS!!

4. Example of energy reconstruction in one module by matrix method of calibration Simulation - 8.3%

5. Plan of construction of the last 12 modules • All components for last 12 modules are at CERN excluding scint. plates. • Delivery plan of the Kharkov firm: • - to deliver 250 pc at CERN before 20 September; • - to deliver 500 pc before 15 October. • Taking this schedule into account and possible delays we propose to postpone • start of modules assembling by INR technicians to beginning of November • and assemble 12 modules during period of ion run when INR team will be here. • Then, the full PSD with new 12 modules can be assembled just after physics run • or later at the beginning of next year. • It is quite undesirable to install this 12 modules (even they will be assembled • before November run because in this case we should disconnect practically all • cables, remove modules from top of the PSD etc. • It is risk that something will be broken during this operation, wrong reconnected etc. • And more important argument that for physics this year this modules are not • necessary.

6. 1540 cm PSD 600cm 100cm 2300 cm from target Beam position of the PSD at Nov2011 ion run ? 30 AGeV, 23 m 40 AGeV, 23 m 80 AGeV, 23 m 158 AGeV, 23 m

7. Status of A-detector and test run at T10 (26 Sep- 10 Oct) New A-detector will be tested at T10, Scintillator bar, 2 spare PMTs (from HADES TOF) and mechanics are available; New electronics- DT5742 Switched Capacitor Digitizer for upgrade NA61 TOF readout will be tested at T10 16+1 channel 12 bit 5 GS/s Switched Capacitor ADC 1 Vpp input dynamics, single ended, 50 Ohm, MCX coaxial connectors Based on DRS4 chip (Paul Scherrer Institute design) 1024 storage cells per channels (200 ns recorded time per event @ 5GSample/s) Memory buffer: 128 events/ch (optional: 1024 events/ch)