Tohban Report 2016-05-04

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Tohban Reports
Start Date: 27 Apr 2016
End Date: 04 May 2016
Tohban: Mitsuo Oka
Tohban email:
Next Tohban: Jim McTiernan
List all reports


Solar Activity

The activity has been low throughout the week, although there were 8 C-class flares. There are currently 7 active regions on disk and they are not showing any complex features. Also, 3 of them are expected to rotate off the disk within a few days.

How many GOES flares occurred?

 Flares above B, C, M, X class were     45     8     0     0

RHESSI flare list contains 3 over the time range 26-Apr-16 03-May-16

No overlapping RHESSI flares to count.

Memory Management

Decimation was active/vigorous for the full time period. Detectors 1, 4 and 7 were turned on during the week. The SSR remained low, emptying at the end of daily pass sets. Spin rate is ~15rpm. Shadow length beginning to decrease, expected minimum on May 14.

Spacecraft Status

Currently, the cold plates 1 and 2 are at 134.4 and 133.1. On 2016-04-27, the cold plates, 1 and 2 were at 134.3 and 132.9 K. Cryocooler power at 72 W. Acceleration is low at around 10mg. Cold tip 1 and 2 temperatures are 112 and 111 degrees.

High voltage turn on (Phase 1) started on April 27. See "Detector issues" below for more details. The power setting was kept at 95% at the time of the turn-on, but was raised to 100% on April 28. It was kept at 100% for the remainder of the week, slightly exceeding the 100% guideline as the temperatures continue to naturally increase due to the declining Sun fraction. Detector 1 is segmented and is being used for the attenuator logic. The threshold values are as follows, given in "% deadtime." A2 is shown for completeness, but is not currently used.

0.00 %   Min A0
6.27 %   Max A0
2.74 %   Min A1
8.23 %   Max A1
1.96 %   Min A2
16.08 %   Max A2
3.53 %   Min A3
100.0 %   Max A3

Adjustments to ADP were also made.

Data Gaps


 GAP START TIME              GAP END TIME                   GAP (SEC)
 2016-04-27T23:25:00.000 -- 2016-04-28T00:00:00.000       2100.0000
 2016-04-28T00:00:00.000 -- 2016-04-28T00:50:00.000       3000.0000

Detector issues

High voltage turn on (Phase 1)

April 27: HV ramped up to 1985 V with no sign of segmentation.

April 28: Cryocooler power raised to 100% and the HV ramped to 3995 V. While D1 is segmented, D4 and D7 are not segmented and they continued to have high slow/fast valid rates.

May 03: HV on D4 & D7 ramped to the maximum voltage ~5000 V, but they were not segmented. Eventually, they were turned off, hoping to minimize additional heating.

So far, D1 is behaving well with the energy resolution of ~1.5 keV. As for threshold changes, on 2016 April 29, D4 Front fast and front-slow thresholds were raised to 0x38 and 0x30, respectively. Also, D7 Front fast and front-slow thresholds were raised to 0x50 and 0x70, respectively.

D3 and D5 are to be turned on after this Ops meeting.

Spacecraft Management

Decimation Active/Vigorous
HLAT Decimation Rear decimation weight 6, no front decimation
Night time data (fronts) +/- 4 minutes
Night time data (rears) +/- 4 minutes
Require extra passes? No
Requirement for moving pointer? No
Attenuator operation Working as expected
Detector problems? See notes above.
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