From:	SMTP%"jrc1@hep.phy.cam.ac.uk" 16-NOV-1997 21:23:18.46
To:	ATLAS-SCT@atlas-lb.cern.ch
CC:	
Subj:	Update on currents of irradiated detectors



               Update on Current Values of Irradiated Detectors
               ________________________________________________

               For Module and System Cooling Specifications
            

Both p-in-n and n-in-n detectors have recently been irradiated to 3 x 10^14
p/cm^2 in the PS (final ATLAS irradiation level with TDR contingency).
3 p-in-n and 3 n-in-n detectors have been annealed to the final level
defined by the (arbitrary) warm-up scenario described in the TDR.
In this sample, there is no systematic difference between the currents of
the p-in-n and n-in-n detectors at a given voltage.  The average current
values measured from 4 detectors at the end of the warm-up are:

              Voltage            Average Current of 1 barrel   Spread between 
                                 detector at -10 deg C          Detectors

               300V                       500 uA                 +- 30uA
               400V                       560 uA                 +- 30uA
               500V                       660 uA                 +- 60uA


Converting these currents to the standard 0 deg C:

               Voltage                 Detector current at 0 deg C
                
                300V                      1346 uA
                400V                      1507 uA
                500V                      1777 uA

Converting to current and power per unit area at 0 deg C for thermal runaway 
calculations:

               Voltage        Current/unit area      Power/unit area
                                   uA/mm^2             uW/mm^2

                300V               0.352                106
                400V               0.394                158
                500V               0.464                232



                                          Janet and Craig