Tohban Report 2015-09-16

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Tohban Reports
Start Date: 9 Sep 2015
End Date: 16 Sep 2015
Tohban: Jim McTiernan
Tohban email:
Next Tohban: TBD
List all reports


Solar Activity

Very little activity, but it's been picking up; all but one of the C flares has been in the last two days.

How many GOES flares occurred?

 Flares above B, C, M, X class were     21    11     0     0

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

 Flares above B, C, M, X class were     10     4     0     0

And how many had EXCELLENT coverage?

 Flares above B, C, M, X class were      9     2     0     0

There were RHESSI flares/GOES flares 35 / 32 over the time range 09-Sep-15 17-Sep-15

Memory Management

Decimation was active/vigorous for the full time period. Both front and rear detectors are off during SC night, except for 4 minutes on either side. The SSR is at 25%, with all BGS passes done for the day.

Spacecraft Status

The cold plates, 1 and 2 were at 135.3 and 133.8 K, on 2015-09-14. The solar array temperature (1) and the Cryocooler power converter temperature are consistently above thier yellow limits, at 100 and 53 C, respectively. Maybe we need a limits change

Data Gaps

VC1 Gaps GAP START TIME GAP END TIME GAP (SEC) 2015-09-09 18:45:00.000 2015-09-09 18:50:00.000 300.00000

VC3 Gaps 2015-09-11 18:25:00.000 2015-09-11 20:00:00.000 5700.0000 2015-09-12 07:35:00.000 2015-09-12 08:50:00.000 4500.0000 2015-09-15 13:25:00.000 2015-09-16T00:00:00.000 38100.000

Detector issues

Detectors 2 and 4 are unsegmented. Detector 9 is not recording events. On Sept 14, we raised the rear fast thresholds on D3 from 0xA0 to 0xB0, and for D6 from 0xF0 to 0xFF, and reduced the HV on D4 to 3600 V.

2015-257-17:33:14 /IDPUTABLE3 OFFSET=REARFASTDAC 2015-257-17:33:22 /IDPLOAD VALUE=0xB0 ; was 0xA0

2015-257-17:35:39 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-257-17:35:49 /IDPLOAD VALUE=0xFF ; was 0xF0

2015-257-17:36:45 /IHVDAC DETECTOR=4, voltage=185 (3602 V, was 3897 V)

Live times increased slightly, but are rapidly decreasing.

On Sept 15 we raised the RHESSI D6 front slow threshold from 0x25 to 0x30, and the D8 front slow threshold from 0x0C to 0x20, to address increased low-energy noise. Little effect on the live-time was noticed.

2015-258-17:09:29 /IDPUTABLE6 OFFSET=frontslowDAC 2015-258-17:09:38 /IDPLOAD VALUE=0x30 ; was 0x25

2015-258-17:09:51 /IDPUTABLE8 OFFSET=frontslowDAC 2015-258-17:10:22 /IDPLOAD VALUE=0x20  ; was 0x15



for the live-time history of the last few days, starting at 2015-09-14 00:00 UT. detectors 3 and 4 front are losing live-time rapidly. All of the working rear detectors (1,3,5,6,7,8) are losing live-time.

Other notes

The thin attenuator was stuck in on 11-Sep-2015. "The thin attenuator went in 2015-254-21:35 UTC. (September 11 2:35 PM local) we were in the back orbit at the time and our first indication came in the early morning Saturday, (1:30 AM local). The good news is that our new attenuator management scheme commanded the attenuator out 2015-257-01:34 UTC. However, these new attenuator commands in the ATS will produced an IDPU error each time an "out" command is issues when the attenuator is already out. These errors could mask a real IDPU error."

We also changed the attenuator logic on 15-sep-2015 as follows: "The thin will now come out at a 3.53% dead time and the thick will come out at 3.92% Given the current performance out of detector 1 and 7 we will probably have to increease these again to allow the attenuator to come out. In the mean time I manually commanded the attenuator out during the pass."

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 See Above
Detector problems? See motes above.
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