First results from silicon and diamond sensors

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First results from silicon and diamond sensors
K. Afanasiev1, I. Emeliantchik1, E.
Kouznetsova2, W. Lohmann2, W. Lange2 1 NC
PHEP, Minsk 2 DESY Zeuthen
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CVD diamond

• Radiation resistant ( up to 10 MGy)
• Fast (charge collection time 10 ps)
• Low dielectric constant gt Low capacitance
• but
• Low signal lt ½ signal from silicon
• Charge collection distance dc

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Si - Diamond comparison
    Silicon CVD-Diamond
Resistivity, Wcm Resistivity, Wcm 2.3105 1013-1016
Carrier density, cm-3 Carrier density, cm-3 151010 lt103
Dielectric constant Dielectric constant 11.9 5.7
Capacitance (1 cm2, 500 mm), pF Capacitance (1 cm2, 500 mm), pF 35 17
Breakdown field, V/cm Breakdown field, V/cm 3105 107
       
Energy/(e--h pair), eV Energy/(e--h pair), eV 3.6 13
Mobility, cm2/(Vs) e- 1350 1800 - 2200
Mobility, cm2/(Vs) h 480 1200 - 1600
       
Average e--h number per 100 mm (for MIP) Average e--h number per 100 mm (for MIP) 9200 3600
Energy deposition per 100 mm (for MIP), keV Energy deposition per 100 mm (for MIP), keV 40 50
Charge collection distance dc, mm Charge collection distance dc, mm   60 - 250 dc  f(l)
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Test Set Up
Si/diamond
5 mm
SC. 2
lead (for cosmics only)
SC. 1
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Test Set Up
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Electronics calibration

• PA VV 50-3
• (charge sensitive)
• ADC CAEN V265 12 bit

Cf
1 pF
gen
50
Cw
Cv gCf
(diamond sensor connected )
ENC 700 e
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Sr source triggering system
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Sr source triggering system
gt mip - signal
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Signals from 90Sr silicon
Si (mip)
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Signals from 90Sr diamond

• Selftriggering

Diamond (whole b-spectra)
Diamond (noise)
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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
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Further steps
New diamond samples

• Fraunhofer Institute (Freiburg)
• (12 x 12 mm)
• 300 and 200 mm
• Different surface treatments
• Prokhorov Institute (Moscow)
• (Dubna group)