From dsmith@apollo.ssl.berkeley.edu Mon Jul 22 12:35:24 2002
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From: David Smith <dsmith@ssl.berkeley.edu>
Reply-To: David Smith <dsmith@ssl.berkeley.edu>
Subject: co-Tohban report, 7/22
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co-Tohban report, 7/22/02, David Smith

We got excellent coverage of the peak of the X-3 flare on July 20 to
make up for missing the rise and peaks of smaller X flares on July 15
and July 18.

M flares were seen on July 17 and 18.

We skipped about 1/2 day of quiet-Sun data twice to manage memory:
Once on July 16 and once on July 21.  The thin shutter was put
in on the 16th, out on the 18th, and back in on the 19th.

On the July 20 flare, once the *thick* attenuator had used up
its 5 chopping cycles during the early decline phase of the X3
flare, it went to its default position -- out (the default
is in for the thin shutter).  This resulted
in some very saturated/piled-up data for the rest of the orbit,
and probably about an extra 10% of the SSR that we wouldn't otherwise
have filled. Hugh Hudson suggested that we might want to reconsider this 
default.

Rear decimation is still occuring at all high magnetic latitude zones
regardless of night/day.  I have nearly completed an algorithm to
identify decimation transitions from quicklook data, which is not 100%
reliable but is much faster than taking spectra for every minute of
the mission.  I will try to get this to Jim and Richard shortly for
approval and I will ask Peter Schroeder to help me in applying it to
the mission data record to date.

On the 17th I lowered the HV on G2 from 2400 to 2000 V to try to
lower the rate of arcing and the rate of resets and electronic
noise counts -- all three had been recently increasing.  The
latter two decreased immediately, and we are waiting to see whether
the detector is now less likely to arc.  Peter Schroeder had
noticed that the arcing had after-effects we hadn't seen before:
for about 1/2 hour after each arc (there was an average of
one per day), the detector efficiency and
gain were both considerably lowered.

Reminder to the new tohban and the operators: please email me right away
when shutter state is changed or decimation changed or 
memory is skipped, for my event pages, including the time the change
takes effect.

Thanks,

David