Tohban Report 2015-12-02

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Tohban Reports
Start Date: 25 Nov 2015
End Date: 2 Dec 2015
Tohban: Jim McTiernan
Tohban email:
Next Tohban: TBD
List all reports


Solar Activity

The sun is quiet: How many GOES flares occurred?

 Flares above B, C, M, X class were      2     1     0     0

RHESSI flare list contains 0 over the time range 24-Nov-15 01-Dec-15

No overlapping RHESSI flares to count, sorry

RHESSI did observe a few flares, but the flare position algorithm is no longer working.

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 16% at the end of the last BGS pass yesterday.

On 30 November (day 334) the SSR read pointer was skipped forward to day 334 at 16:00 UTC. This skip dropped the SSR fill level from 55% to 12% full, and essentially skipped over data recorded between 29-Nov-2015-12:00 and 30-Nov-2015-16:00 UTC.

Spacecraft Status

The cold plates, 1 and 2 were at 136.9 and 135.4 K, on 2015-11-30.

Data Gaps

No VC1 Gaps

VC3 Gaps



2015-11-25T18:10:00.000 -- 2015-11-25T18:15:00.000 300.00000

2015-11-29T11:55:00.000 -- 2015-11-30T00:00:00.000 43500.000

2015-11-30T00:00:00.000 -- 2015-11-30T16:00:00.000 57600.000

Detector issues

(From B. Dennis)

Detector 2 is unsegmented, Detector 9 is off, detector 4 is not recording events.

Front detectors:

Detectors 1, 5, and 7 look normal but see below for problem with Detector 7 imaging. Detector 3 has pulses only above ~100 keV. Detector 4 has no front segment counts (D4 is not recoreding events). Detector 6 has high low energy counting rate possibly leading to high pulse pile-up from ~15 to 40 keV. Suggest increasing slow threshold to ~10 keV. Detector 8 has very few counts and high dead time. Detector #9 is off.

On 25-Nov-2015, we increased thresholds on G7 and G3, and preformed a 200 V HV drop on detector 7 and Rear fast threshold change on G5.

2015-329-21:24:25 /IDPUTABLE3 OFFSET=FRONTSLOWDAC 2015-329-21:24:36 /IDPLOAD VALUE=0x30  ; was 0x15

2015-329-21:24:47 /IDPUTABLE7 OFFSET=FRONTSLOWDAC 2015-329-21:24:59 /IDPLOAD VALUE=0x30  ; was 0x10

2015-330-00:27:47 /ihvdac detector=7, voltage=181 (3504 V)

2015-330-00:28:40 /IDPUTABLE5 OFFSET=REARFASTDAC 2015-330-00:28:49 /IDPLOAD VALUE=0xA0 ; was 0x90

On 30-Nov-2015, we decreased the HV on detector 3 in 4 steps of approximately 200 V each, lowering the HV from 2255 to 1470 V. We also increased again the G3 front slow threshold from 0x50 to 0xC0.

2015-334-22:24:52 /ihvdac detector=3, voltage=107 2015-334-22:25:51 /ihvdac detector=3, voltage=97 2015-334-22:26:32 /ihvdac detector=3, voltage=87 2015-334-22:27:21 /ihvdac detector=3, voltage=77 (1470 V)

2015-334-22:28:41 /IDPUTABLE3 OFFSET=FRONTSLOWDAC 2015-334-22:28:50 /IDPLOAD VALUE=0xC0  ; was 0x50

On 1-dec-2015, we decreased the HV on G3 by 200 V, lowering the HV from 1274 V.

Other notes

On 25-Nov-2015 the detectors used in the attenuator logic were changed to from 1,1,7, and 7 to 1,1,5, and 5, and a new attenuator threshold table was loaded using 2008 values as the base and the current background, 10.2% as the offset:

threshold deadtime

Minl0 0.0 %

Maxl0 15.3 %

Minl1 11.7 % (this is where the thin comes out)

Maxl1 17.2 %

Minl2 11.0 %

Maxl2 25.1 %

Minl3 12.5 % (this is where the thick comes out)

Maxl3 100 %

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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