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

2 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 d c :

3 Si - Diamond comparison SiliconCVD-Diamond Resistivity,  ×cm 2.3× Carrier density, cm -3 15×10 10 <10 3 Dielectric constant Capacitance (1 cm 2, 500  m), pF 3517 Breakdown field, V/cm3× Energy/(e - -h pair), eV3.613 Mobility, cm 2 /(V×s) e-e h Average e - -h number per 100  m (for MIP) Energy deposition per 100  m (for MIP), keV 4050 Charge collection distance d c,  m ; d c = f(l)

4 Test Set Up 5 mm SC. 2 SC. 1 Si/diamond lead (for cosmics only) Sr/cosmics & Gate PA discr delay ADC

5 Test Set Up

6 Electronics calibration PA : VV 50-3 (charge sensitive) ADC : CAEN V bit ENC = 700 e (diamond sensor connected ) gen 50 1 pF CwCw C v = g·C f CfCf

7 Sr source + triggering system 5 mm 90 Sr SC. 2 SC. 1 Si/diamond (300  m) &

8 Sr source + triggering system E mip = 1.25 MeV dE/dx = 3.56 MeV/cm R = 0.3 cm E mip = 1.5 MeV dE/dx = 5.57 MeV/cm R = 0.2 cm => ~mip - signal

9 Signals from 90 Sr – silicon : Si (mip)

10 Signals from 90 Sr – diamond : Selftriggering: discr delay in gate ADC PA diamond Sr Diamond (noise) Diamond (whole  - spectra)

11 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 Problems and further steps : Expected noise ≤ 350 e

12 Fraunhofer Institute (Freiburg) :  (12 x 12 mm)  300 and 200  m  Different surface treatments Prokhorov Institute (Moscow) (Dubna group) Further steps : New diamond samples :