Tohban Report 2014-04-23
From RHESSI Wiki
|Start Date:||16 Apr 2014|
|End Date:||23 Apr 2014|
|Next Tohban:||Hazel Bain, with backup Hugh Hudson|
|List all reports|
Activity is low to moderate, with lots of C flares (10 in last 24 hours). There are 10 active regions on the disk, with at least 5 producing C flares. There was a brief Major Flare Watch on the 18th in response to an M7.3 flare, but that AR started decaying soon after.
How many GOES flares occurred?
Flares above B, C, M, X class were 0 65 2 0
And how many of these are listed in the RHESSI flare list?
Flares above B, C, M, X class were 0 46 2 0
The SSR fill level had been relatively high (20-40%) throughout the week.
The SSR reached a high fill of over 40% a week ago due to detector noise. Changes were made to D9 and D6 In response to this, and these changes were successful in reducing excess counts and the memory fill steadily dropped afterwards. The memory is now emptying regularly.
No data gaps.
D6 and D9 were contributing a huge excess of noise counts that was stressing the memory. On the 17th, the front slow threshold on detector 9 was raised and the voltage was dropped on detector 6. This was effective in reducing the noise problem in both detectors.
Detector 8 rear segment is swamped by fast counts, so on April 18 the voltage was dropped on that detector. That had essentially no effect. Today, raised the detector 8 rear fast threshold to the max to see if that buys us anything. (Update: these seems to have been successful.)
The other detectors seem to be operating stably.
Detectors used for the livetime calculation are currently 1,2,5,7. I didn't see any bad attenuator motions this week.
April 23, 18:40 UTC: D8 rear fast threshold was raised to 0xFF.
2014-108-19:53:15 UTC: Detector 8 HV was dropped by 10 counts to 117 counts, or 2279 V.
14-107-16:26:00 /IDPUTABLE9 FRONTSLOWDAC 14-107-16:26:29 /IDPULOAD VALUE=0x1A
14-107-16:27:09 /IHVDAC DETECTOR=6, VOLTAGE=108
14-106-18:24:17 UTC: The detector set used for the livetime calculation was changed to G1, G2, G5, and G7. (This was in response to the attenuator issues last week.)
The idea of a second/backup tohban was discussed, since there are so many detector and related issues to watch out for that it's getting to be a bit much for one person to do. The second tohban will provide a second pair of eyes watching for things like spurious attenuator changes, increases in detector noise, or other problems. Since there's an extremely limited number of tohbans at SSL, the second tohban will be an outside volunteer (which also gives better time coverage).
|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|
|Detector problems?||6, 8, 9|