Shift report A July 28 1999, 8:00am EDT, GMT 209:12:00

We had a GREAT night.  We turned on the CCDs for the first time and
all is well !!!!!!


ACIS Activities this Shift

1. Set Focal Plane to -90 C
2. Load Standard Patches
3. Diagnostic Mode
4. Raw Mode 
5. OBF Integrity
6. Dark Current


Spacecraft Activities:
  - a rather extreme yaw of 167 degrees 
  
Quick Notes:
1. Set Focal Plane -90 C
   - Yousaf reports a change to the procedure to identify the
correct scripts

2. Load Standard Patches
  - OCC command system is running very slow, this causes a couple of
commands to be skipped which prevents the warm boot from taking
effect.  The solution is to change the "Clear to Send Mechanism" to
"CAR" and to disable the FSV processing.

3. Diagnostic Mode
  -  All ten CCDs are powered for the first time !!!!!
  - The electronics look good !!!!
  
4. Raw Mode
  - We sent down 2 raw frames from each of the ten CCDs 
and all look OK.

5. OBF Integrity Test
  - We collected biases with the LED on and off.   This tells
us that the OBF is still intact.  Good news !!!!
 

6. Dark Current Measurement
  - We collected biases at 3.3s and 9.9s at -90 C and -110 C.
We will do -120 C 12 hours from now after our perigee passage.
  - there was a typo in the first script I_1_DARK_CUR_A.ssc for the
the first command load, it is "1A_WD001_137.CLD", it should be
"1A_WD000_137.CLD"


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More detailed notes from Mark Bautz:

Notes from ACIS CCD Checkout Activities, Shift A6

ACIS CCDs were read out for the first time since the launch of Chandra. All 
detectors are transferring charge as expected, and overclock noise levels
are consistent with pre-launch values (2.5 electrons, RMS, or better).  The optical
blocking filters are intact.  Dark current levels, measured at focal plane temperatures
of -90C and -110C are as expected.

Observed raw background event rates are about a factor of two higher than expected.
We have not yet measured background rejection efficiency.  

The instrument successfully
computed bias maps for each detector. The default bias-computation parameter values
provide excellent performance for the back-illuminated detectors. Bias maps for the
front-illuminated detectors show some residual charge from charged particle events. 
This residual charge adds the equivalent of  about 1.5 electrons, RMS, in quadrature,
to bias map noise.  We expect to be able to reduce this residual charge by adjusting
bias compuation parameters.

In summary, ACIS detectors, analog signal chains and optical blocking filters appear
to be in excellent health.

**************************************************************************************

Data processing
- most of the realtime data has been processed into images and
examined by Shanil and Steven


Staff for this shift

ACIS: Bob Goeke, Mark Bautz, Peter Ford, Royce Buehler, Yousaf Butt,
Paul Plucinsky, Shanil Virani, Michael Pivovaroff, Gordon Garmire,
Steven Buczkowski

SOT Lead: Bill Podgorski
ACA: Rob Cameron
EPHIN: Eric Martin



Paul