Electrical features of diamond sensors

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Electrical features of diamond sensors
D. Drachenberg, E. Kouznetsova, W. Lange, W.
Lohmann
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Diamond samples

• Fraunhofer Institute (Freiburg)
• (12 x 12 mm)
• 300 and 200 um
• Different surface treatments
• 1 substrate side polished 300 um
• 2 cut substrate 200 um
• 3 growth side polished 300 um
• 4 both sides polished 300 um
• Metallization

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Main characteristics initial measurements

• I(V) curve leakage current
• two polarities
• Charge collection distance before irradiation
• Sr-source
• two polarities

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I(V) dependence

• Extremely low currents
• gt
• Shielding
• N2 atmosphere

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I(V) dependence
Open circuit measurements
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I(V) dependence
Usual I(V) curve
Non-ohmic curve
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I(V) dependence
Time dependence
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I(V) dependence
Reproducibility
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IV dependence
Comparison
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I(V) dependence

• Current results
• Average resistance (1013-1014) Ohm (ohmic
  behavior)
• Different I(V) behaviors were obtained even
  within groups of the same surface treatment
• I(t) dependence shows polarization effects which
  correspond to the hysteresis of the I(V) curves
• Further steps
• long term measurements
• under irradiation

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Charge collection distance measurements for
diamond sensors
D. Drachenberg, E. Kouznetsova, W. Lange, W.
Lohmann
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CCD
Qmeas. Qcreated x ccd / L

• Not irradiated samples
• CCD f(HV)
• Both polarities

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SimulationsSr diamond
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Spectra obtained noise and Sr signal
noise
Sr
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CCD- before irradiation (1)
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CCD- before irradiation (2)
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CCD- before irradiation
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SimulationsAm diamond
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CCD a spectra
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CCD

• Current results
• Values of CCD before irradiation
• (10 - 60) um
• Surface treatment has an influence on CCD
• Good resistance doesnt mean high CCD
• Further steps
• Measurements of CCD dependence on an irradiation
  dose
• Surface test
• measurements with an a-source
• ( 10 um of penetration)
• Homogeneity over the area
• with a narrow collimated Sr