Tohban Report 2014-08-27

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Tohban Reports
Start Date: 20 Aug 2014
End Date: 27 Aug 2014
Tohban: Lindsay Glesener
Tohban email:
Next Tohban: Hazel Bain
List all reports


Solar Activity

There was low / medium solar activity this week. There is one AR producing several C class flares still on the disk now, but it will rotate off the disk in the next few days.

How many GOES flares occurred?

 Flares above B, C, M, X class were     10    46     5     0

And how many of these are listed in the RHESSI flare list?

 Flares above B, C, M, X class were      2    29     4     0

And how many had EXCELLENT coverage?

 Flares above B, C, M, X class were      0     0     0     0

There were RHESSI flares/GOES flares 223 / 61 over the time range 19-Aug-14 26-Aug-14

Memory Management

The SSR is emptying at the end of the daily pass set, with a maximum fill of 25%. (Note that this is even after we made the change to normal / vigorous from active vigorous late last week.)

Because we have memory to spare, and because David would like eclipse data to aid a new wave of TGF work, we will turn on eclipse data for both the front and rear segments. The next tohban should keep a close eye on the memory after this change takes effect.

Spacecraft Status

The segmentation status has not changed, with 1,3,8, and 9 stably segmented and D6 segmented most of the time, but losing segmentation during/following SAA passages. This segmentation is expected to become more stable over time.

Data Gaps

There were no data gaps.

Detector issues

Detector 9 was noisy last week, so the voltage was dropped by 20 steps on August 20. (See commanding list below.) This succeeded in eliminating the noise.

Similarly, Detector 2 became noisy starting on the 20th, so its HV was dropped by 20 steps on August 21. This also worked.

The recurring light leak issue has reared its ugly head. As usual, this produces fast rates in D2 and D3 (and to a lesser extent in some of the others, notably D5 and D9) at times when Earth glow leaks into the cryostat. This does not harm the detectors but cuts into the livetime. Because D2 is unsegmented and D3 is segmented, the problem shows up in the front fast rates for D2 and the rears for D3. To mitigate the problem, the D2 front fast threshold was raised from 0x30 to 0x38 and the D3 rear fast threshold was raised from 0x45 to 0x50 on August 26. (See command list below.) An initial look shows that this didn't fix the problem, but we should wait for a bit more data before determining if more steps should be taken.

Spacecraft Operations

On August 20 (DOY 232) at 20:57 UT, several changes were made:

On August 21 (DOY 233) at 20:41:14 UT, the HV on D2 was lowered by 20 counts to 4117V.

On August 26 (DOY 238) the following threshold changes were made:

On August 27 (DOY 239) the following changes were made, at 20:39 UT:

Other notes

Several other topics were discussed; please see individual emails and presentations for details. Topics included:

Decimation Normal/Vigorous
HLAT Decimation Rear decimation weight 6, no front decimation
Night time data (fronts) +/- 4 min for most of week, changed to full eclipse data today.
Night time data (rears) +/- 4 min for most of week, changed to full eclipse data today.
Attenuator operation Active
Detector problems? Noise in 2, 9, but resolved.
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