Tohban Report 2015-09-02

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Tohban Reports
Start Date: 26 Aug 2015
End Date: 2 Sep 2015
Tohban: Juan C. Martinez Oliveros
Tohban email: oliveros@ssl.berkeley.edu
Next Tohban: Mitsuo Oka
List all reports



Contents

Solar Activity

Solar activity was moderate at the beginning of this week but now it remains low. There are currently 4 ARs on the disk with the probability of some isolated C class flare in the following days.

How many GOES flares occurred?

 Flares above B, C, M, X class were      4    37     4     0

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

 Flares above B, C, M, X class were      3    31     3     0

And how many had EXCELLENT coverage?

 Flares above B, C, M, X class were      2    21     1     0

There were RHESSI flares/GOES flares 152 / 45 over the time range 26-Aug-15 02-Sep-15


Memory Management

The SSR fill level reached a maximum of ~54% and a minimum of about ~24% during the week.

The SSR fill level seems to be better at the end of this week, but it is unclear if the reason are the changes performed to the instrument or the decrease in solar activity or both.

Spacecraft Status

The cold plate 1 and 2 are at about 134.4 K and 133.3 K respectively.

Data Gaps

GAPS IN APP_ID = 102 (VC3-MONITOR RATES) WITH PACKET RATE LT 30
N_GAPS           1
GAP START TIME              GAP END TIME                   GAP (SEC)
2015-08-28T12:20:00.000 -- 2015-08-28T12:25:00.000       300.00000

Detector issues

The focus of this week was to lower the ssr fill volume, and in particular to work with detectors 4 and 6.

Detector 3: The front slow count rates were elevated, to try to bring them down we raised the slow front threshold by 0x10 on August 27th. This has an immediate effect lowering the slow front counts by a factor of 2. We also raised the front and rear fast threshold to increase the livetime.

2015-239-17:57:41 /IDPUTABLE3 OFFSET=FRONTSLOWDAC
2015-239-17:57:50 /IDPLOAD VALUE=0x1C  ; was 0x0C
2015-239-19:33:13 /IDPUTABLE3 OFFSET=REARFASTDAC
2015-239-19:33:23 /IDPLOAD VALUE=0xA0 ; was 0x90
2015-239-21:13:25 /IDPUTABLE3 OFFSET=FRONTFASTDAC
2015-239-21:13:33 /IDPLOAD VALUE=0x60  ; was 0x50

Detector 4: As was discussed during the last meeting, detector 4 showed elevated slow front rates. Following the suggestions of the previous tohban, on August 27 the slow front threshold was increased but no change was observed at all. As the front fast rates were also elevated, a change in the front fast threshold was performed. This change increased its livetimes and the slow front rates, as was expected. Then we decrease D4 HV by 200V, a very conservative value as we would like the detector to segment. However the HV change did not have any impact the front slow rates. The detector remains in the same condition with the slow front threshold at 0xC3.

2015-239-17:55:53 /IDPUTABLE4 OFFSET=FRONTSLOWDAC
2015-239-17:56:02 /IDPLOAD VALUE=0x90  ; was 0x80
2015-239-17:56:56 /IDPUTABLE4 OFFSET=FRONTSLOWDAC
2015-239-17:57:05 /IDPLOAD VALUE=0xA0  ; was 0x90
2015-239-19:34:23 /IDPUTABLE4 OFFSET=FRONTSLOWDAC
2015-239-19:34:32 /IDPLOAD VALUE=0xC0  ; was 0xA0
2015-239-19:37:01 /IDPUTABLE4 OFFSET=FRONTFASTDAC
2015-239-19:37:09 /IDPLOAD VALUE=0xF0  ; was 0xE0
2015-239-19:39:38 /IDPUTABLE4 OFFSET=FRONTSLOWDAC
2015-239-19:39:47 /IDPLOAD VALUE=0xC3  ; was 0xC0

We lowered G4 HV from 4500 to ~4300V

Detector 7: On August 27 D7 rear fast threshold was rasied to increase its livetime. 2015-239-17:58:24 /IDPUTABLE7 OFFSET=REARFASTDAC 2015-239-17:58:32 /IDPLOAD VALUE=0x80 ; was 0x70


Detector 6: Other detector showing elevated slow front rates is detector 6. We made a HV change on August 28, lowering the voltage by 200V. The change made the slow front rates to decrease, but still the detector shows elevated slow front counts. On August 31, the rear fast threshold was raised to increase the detector livetime.

2015-240-17:32:26 /ihvdac detector=6, voltage=93 (from 1984 to 1789 V)
2015-243-18:01:47 /IDPUTABLE6 OFFSET=REARFASTDAC
2015-243-18:01:56 /IDPLOAD VALUE=0xE0 ; was 0xD0

Detector 8: Detector 8 fast front threshold was raised on August 28.

2015-240-17:35:09 /IDPUTABLE8 OFFSET=FRONTFASTDAC
2015-240-17:35:18 /IDPLOAD VALUE=0x60  ; was 0x50

Detector 2: Detector 2 fast front threshold was raised on August 28.

2015-240-20:51:39 /IDPUTABLE2 OFFSET=FRONTFASTDAC
2015-240-20:51:49 /IDPLOAD VALUE=0x70  ; was 0x60


In conclusion: detectors 3,4,6 and 8 still show elevated slow front rates. It is recommended to the next tohban to keep an eye on detectors 6 and 8.


Other notes

Spacecraft Management

Decimation Active/Vigorous
Night time data (fronts) +- 4 minutes
Night time data (rears) +- 4 minutes
Require extra passes? No
Requirement for moving pointer? No
Attenuator operation Normal
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