Tests on sensors delivered from Hamamatsu
Tests on sensors delivered from Hamamatsu
The silicon detectors were hand delivered to
Fermilab on December 10th 1999.
Six detectors (3 wide, 3 narrow) were taken to Liverpool for testing.
This plot shows the I-V characteristics for the 6 sensors.
Comparing to the Hamamatsu spec-sheets we note:
The currents are about half that in the spec-sheets.
This is probably because we waited 10 minutes for the sensors
to reach equilibrium before starting the measurements.
One sensor experiences breakdown at 450V instead of the
800V on the spec-sheet. We are currently attempting to
see if this is an intrinsic fault of the detector or
not.
We have
measured the interstrip capacitance on all detectors
to be about 1.2 pF/cm.
The capacitance including the first and second nearest neighbours
(but not the back plane) is
about 9pF over a length of 7.84cm.
The results are not strong functions
of frequency, bias voltage or detector type.
Update on the bad sensor
The bad sensor was washed in order to clean away surface contaminants.
This improved its performance as can be seen in the updated plot of
IV characteristics.
The interstrip capacitance
and the CV curve for this sensor
also look normal.
Summary of Detector Characteristics
We have measured the following properties of the detectors:
| Strip implant resistance cm-1 | ~ 95 kOhm/cm |
| Polisilicon resistors | ~ 2.5 MOhm |
| Interstrip capacitance | ~ 1.15 pF/cm |
| Strip to backplane cpacitance | ~ 0.19 (+- .03) pF/cm |