A. Calcaterra, R. de Sangro, G. Felici, G. Finocchiaro, P. Patteri, M. Piccolo INFN LNF XIII SuperB General Meeting DCH-I parallel session Elba, 30 May 2010

Experimental Setup 30/05/20102G. Finocchiaro Prototype 1  6x4 hexagonal cells à la B A B AR – Guard wires to ensure uniformity of electric field among cells – Aluminized mylar windows on entrance-exit faces – small gas volume low rate on cosmics fast gas mixture switching times LST Telescope:  Two identical assemblies of 26 tubes each  3 cm diameter, 100 μm wires  40%-60% Ar-iC 4 H 10 mixture

Tracks extrapolated in Proto1 30/05/20103G. Finocchiaro Mylar windows 10cm lead p cut ~150MeV/c

Tracks extrapolated in Proto1 30/05/20104G. Finocchiaro

Illumination from tracks in Proto1 30/05/20105G. Finocchiaro …in the four internal layers 80%He-20%iC 4 H HV=1960V

Illumination from tracks in Proto1 30/05/20106G. Finocchiaro …in the four internal layers 80%He-20%iC 4 H HV=2160V

Track Impact Parameter Resolution 30/05/20107G. Finocchiaro Telescope single tube spatial resolution ~100  m

Space-Time Relations 30/05/20108G. Finocchiaro 95%He-5%iC 4 H HV=1600V

Space-Time Relations 30/05/20109G. Finocchiaro 95%He-5%iC 4 H HV=1600V

Track Fit Residuals 30/05/201010G. Finocchiaro 95%He-5%iC 4 H HV=1600V

Spatial resolution – 95%He-5%iC 4 H 10 30/05/201011G. Finocchiaro HV=1550V HV=1650V

Spatial resolution – 80%He-20%iC 4 H 10 30/05/201012G. Finocchiaro HV=1960VHV=2160V

35%He-65%CH 4 - HV=2760V 30/05/201013G. Finocchiaro t vs. xQ vs. x

35%He-65%CH 4 - spatial resolution 30/05/201014G. Finocchiaro HV=2760V cell (3,2) cell (2,2)

51%He-49%CH 4 - t vs x 30/05/201015G. Finocchiaro 2460V 2410V 2360V

51%He-49%CH 4 - Q vs x 30/05/201016G. Finocchiaro 2460V 2410V 2360V

51%He-49%CH 4 - spatial resolution 30/05/201017G. Finocchiaro HV=2460VHV=2410V

67%He-33%CH 4 - t vs x 30/05/201018G. Finocchiaro 67%He-33%CH HV=2510V 67%He-33%CH HV=2410V

67%He-33%CH 4 - Q vs x 30/05/201019G. Finocchiaro 67%He-33%CH HV=2510V 67%He-33%CH HV=2410V

67%He-33%CH 4 - spatial resolution 30/05/201020G. Finocchiaro HV=2510V HV=2410V HV=2310V

79%He-21%CH 4 - t vs x 30/05/201021G. Finocchiaro HV=2210V HV=2110V

79%He-21%CH 4 - Q vs x 30/05/201022G. Finocchiaro HV=2210V HV=2110V

79%He-21%CH 4 - spatial resolution 30/05/201023G. Finocchiaro HV=2210V cell (3,2) cell (2,2)

Gas Mixture Comparison 19/03/2010G. Finocchiaro24  (g/cm 3 ) x1 0 4 X0(m)N P (cm  )N T (cm  )t max (ns)  (  m) 80%He-20%iC 4 H %He-10%iC 4 H %He- 5%iC 4 H %He-65%CH %He-49%CH %He-33%CH %He-21%CH N.B.: t max and space resolution depend on other parameters. Figures shown are preliminary and indicative.

Read 4 channels of proto1 through DRS4 (*) “evaluation board” Channel arrangement chosen to see cosmic ray tracks Same channels (after active splitters) as in the standard DAQ chain Waveform Digitization 30/05/2010G. Finocchiaro25 (*) A switched capacitor array (SCA) with 1024 cells, capable of digitizing eight analog signals with high speed (6 GSPS) and high accuracy (11.5 bit SNR) on a single chip ( [only 4 channels read-out with current version of firmware] Same acquisition trigger (scintillator counters coincidence) as telescope+proto1 setup shown so far − Due to technical reasons, still recording events using different programs (running on different computers!)  work in progress to correlate waveforms with reconstructed tracks −Proto1 preamp bandwidth only ~100MHz  just a sandbox for now

We see coincidences! Waveform Digitization 30/05/2010G. Finocchiaro26 80%He-20%iC 4 H 10 HV=2060V

…and could even count clusters! (with low efficiency, and a lot of fantasy…) Waveform digitization 30/05/2010G. Finocchiaro27 80%He-20%iC 4 H 10 HV=2060V

Waveform digitization 30/05/2010G. Finocchiaro28 97%He-3%iC 4 H 10 HV=1500V Events are written to disk, and read back

Waveform digitization 30/05/2010G. Finocchiaro29 80%He-20%iC 4 H 10 - HV=1960V First 200 waveforms for the four channels (not on the same scale) RMS ~2mV

Time Spectra with varying thresholds 30/05/2010G. Finocchiaro30 80%He-20%iC 4 H 10 - HV=1960V - 5 mV - 10 mV - 12 mV - 15 mV

Summary First preliminary v drift and spatial resolution results on He-based gas mixtures with different quencher contents – important dependence on other operating conditions, e.g. HV and discrimination threshold see also Matteo’s talk in DCH session #2 on the B A B AR DCH performances Starting waveform digitization studies – faster preamps, and full integration with DAQ program next steps 30/05/2010G. Finocchiaro31