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First results from silicon and diamond sensors. K. Afanasiev 1 , I. Emeliantchik 1 , E. Kouznetsova 2 , W. Lohmann 2 , W. Lange 2 1 NC PHEP, Minsk 2 DESY Zeuthen. CVD diamond :. Radiation resistant ( up to 10 MGy) Fast (charge collection time ~ 10 ps)
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First results from silicon and diamond sensors K. Afanasiev1, I. Emeliantchik1, E. Kouznetsova2, W. Lohmann2, W. Lange2 1NC PHEP, Minsk 2DESY Zeuthen
CVD diamond : • Radiation resistant ( up to 10 MGy) • Fast (charge collection time ~ 10 ps) • Low dielectric constant => Low capacitance but • Low signal : < ½ signal from silicon Charge collection distance dc:
Sr/cosmics ADC PA delay discr & Gate discr Test Set Up Si/diamond 5 mm SC. 2 lead (for cosmics only) SC. 1
PA : VV 50-3 (charge sensitive) ADC : CAEN V265 12 bit Electronics calibration Cf 1 pF gen 50 Cw Cv = g·Cf (diamond sensor connected ) ENC = 700 e
90Sr Si/diamond (300 mm) 5 mm SC. 2 & SC. 1 Sr Sr Y Y E, MeV Sr source + triggering system
Emip = 1.25 MeV dE/dx = 3.56 MeV/cm R = 0.3 cm Emip = 1.5 MeV dE/dx = 5.57 MeV/cm R = 0.2 cm Sr source + triggering system => ~mip - signal
Signals from 90Sr – silicon : Si (mip)
Sr ADC delay in PA diamond discr gate Signals from 90Sr – diamond : • Selftriggering: Diamond (whole b-spectra) Diamond (noise)
Problems and further steps : • Noise level is not optimal for signal/noise separation • Possible solutions : • Noise optimization of the existing preamplifier or • Switch to Amptek A250: • New trigger scintillator matching the size of the sensor Expected noise ≤ 350 e
Further steps : New diamond samples : • Fraunhofer Institute (Freiburg) : • (12 x 12 mm) • 300 and 200 mm • Different surface treatments • Prokhorov Institute (Moscow) (Dubna group)