Tohban Report 2015-09-02
| 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 | |
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 |