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Summary of First Laser Measurements on Irradiated Detectors. Nicholas Ptak Colin Parker 2/1/11. Introduction. So far, 7 irradiated detectors have been tested at different temperatures W17-BZ2 at –15C [4x10^12 p-stop,1x10^13 protons] W17-BZ4D at –10C [4x10^12 p-stop,1x10^13 protons]
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Summary of First Laser Measurements on Irradiated Detectors Nicholas Ptak Colin Parker 2/1/11
Introduction • So far, 7 irradiated detectors have been tested at different temperatures • W17-BZ2 at –15C [4x10^12 p-stop,1x10^13 protons] • W17-BZ4D at –10C [4x10^12 p-stop,1x10^13 protons] • W18-BZ2 at –15C [4x10^12 p-stop,1x10^13 protons] • W18-BZ4C at –10C and –15C [4x10^12 p-stop,1x10^13 protons] • W18-BZ4D at –15C [4x10^12 p-stop,1x10^13 protons] • W50-BZ2 at –15C [4x10^12 p-stop,1x10^13 protons] • W50-BZ4D at –10C [4x10^12 p-stop,1x10^13 protons]
Farside Punchthrough • In most detectors, there seemed to be no punchthrough on the farside. The voltages on the near and far sides were very close to equal, and limits on the resolution of the measurements as well as other possible unaccounted for resistances made it difficult to show 0 current on the strip, and sometimes resulted in calculations of negative Reff. • Only 1 detector so far has shown punchthrough on the far side. The tests on the W17-BZ4D and W18-BZ4D detectors were done at two different temperatures and show the difference in Reff far with temperature • W50-BZ4D also showed a possibility for punchthrough
Saturation • Some of the detectors tested seemed not to reach saturation at 200 volts • Including higher bias voltages should be considered for future tests
Current vs Reff • It was also noted that the current vs Reff curves roughly followed a i^-0.5 dependence for the near side punchthrough
Comparison with non-irradiated detectors • One test was done so far to compare irradiated with non-irradiated detectors • The current in the irradiated detector was lower and Reff higher • Neither detector reached saturation before 200V bias
Summary • Farside punchthrough is only seen in some detectors • The detectors should be tested at higher bias voltages to look at saturation • The next tests will be done on the W50 zone 4s to compare punchthrough structures and in comparisons with non-irradiated detectors