ACIS Shift report M357 Jul 14 1700, GMT 196:21:00


PLAN:
 
   The plan was to execute CAP 635 to collect more Squeegy mode data
on I0 in the maximum angular resolution case.

SUMMARY:

   The radiation environment was too high to permit ACIS operations.
Therefore, we did not execute any of CAP 635.  Rather, we wrote CAP
636 to send one command to power down the FEPs.


NEXT PLAN:

   Tomorrow (Saturday July 15th) we have a COM at 2:20pm local time.
If the radiation levels subside enough that it is safe to operate ACIS,
we would like to start a CTI measurement to see if this "Hard" proton
event has produced damage in the CCDs.


1) Detailed Timeline:

GMT
196:19:30   AOS on DSS 66
196:19:31   FP temp = -113.2 C, YIKES ! that is warm ! good thing we
	    did Squeegy R7 yesterday.
196:19:35   EPHIN rates
	    E150=50048, E300=28864, E1300=9024, P4=14464, P41=2120  cts/sample
	    altitude 42457 km
	    These rates are a factor of 4-20 times higher than the 
	    thresholds at which we safe the SIs.  Therefore, we cannot
	    turn on ACIS.
196:20:00   We drop off to participate in the telecon to discuss the
	    high radiation environment.
196:21:00   Telecon decides to terminate the load.
196:21:30   execute CAP 636 to power-down the FEPs
196:21:50   EPHIN rates
	    E150=50176, E300=29952, E1300=8896, P4=15680, P41=2112 cts/sample
	    altitude 61760 km
	    Notice how the rates have roughly stayed the same even though
	    Chandra is now at 62,000 km.  So, we clearly are seeing a very
	    high radiation environment outside of what we would typically
	    consider the radiation belts.
196:22:00   FP temp = -119.2 C
	    focal plane is cooling very slowly.
196:22:25   FP temp = -119.9 C
196:23:30   LOS 


SOT LEAD: Tom Aldcroft
ACIS: Paul Plucinsky, Catherine Grant, Bev LaMarr