M. Bonesini - 3/10/061 M. Bonesini INFN Milano Some results from BTF testbeam on TOF

M. Bonesini - 3/10/062 The BTF testbeam Testbeam at BTF for 10 days in July 06 Data taken both with MCA and full DAQ setup We have tested TOF resolutions, not rate effects (for this we can do only lab tests with our laser system) Energy range MeV e - /e + Max rep rate50 Hz Pulse duration 10 ns Current/pulse particles

M. Bonesini - 3/10/063 electron beam finger 1 Bar 1 Bar 2 Bar 3 finger 2 PMT left scintillator PMT right TOF bar Discr PLS711 TAC Ortec 566 MCA Ortec Trump 8K TAC measures t_ L -t_ R

M. Bonesini - 3/10/064 MCA Maestro analysis data were analized online with the MAESTRO program (WINDOWS based) later they were reanalized offline (see plots) writing ASCII files from saved MCA plots and fitting results with a gaussian in PAW results are marginally worse (eg typically <10% increase in resolution)

M. Bonesini - 3/10/065 Comparison MCA analysis-PAW reanalysis Left is BC420 re- analized data, next slide the original MCA Maestro data  t ~56 ps

M. Bonesini - 3/10/066  t  ps

M. Bonesini - 3/10/067 4cm width bars: UPS95F  t ~56 ps  t ~50 ps Lightguide is a Winston coneLightguide is fishtail

M. Bonesini - 3/10/068 4cm bars: BC420  t ~56 ps  t ~ 63 ps Lightguide fishtail BC800 Lightguide fishtail REPSOL glass

M. Bonesini - 3/10/069 6cm bars: BC404, BC420, BC408  t ~46 ps  t ~45 ps  t ~60 ps Long non-gaussian tails BC-404 / BC-420 seem equivalent, BC-408 (as expected) worse

M. Bonesini - 3/10/0610 Position scan along a BC420 bar resolution is worse at the edges probably due to the PMT rough gain calibration (but still ~ 60 ps) x=0 cm is the edge of the bar, x=20 cm the center

M. Bonesini - 3/10/0611 Conclusions BC420 scintillator seems more than adequate, but also low-cost UPS95F or BC404 are valid alternatives no gain from complicate lightguide design (Winston cone) as respect to simple fish-tail one Resolution with FAST conventional PMTs (R4998) seems better than with 1” fine-mesh PMTs results depend heavily on BTF beam instabilities, but resolution is fine ~60 ps: in principle an MCA analysis must give worse results than a “full glory” analysis taken with DAQ (ADC infos, more clever beam selection, …) unless you have problems with TDC (but CAEN V1290 claimed resolution is 35 ps against V775 resolution of 28 ps), DAQ, data treatment …