From RHESSI Wiki
This page contains information about changes/issues for RHESSI detector 9 after the 2014 anneal. Detector updates from 2012-mid 2014 can be found here: Detector 9 anneal 2012
Notes
Detector 9 is SEGMENTED after the 2014 anneal!
- 2014 August 20: Due to sporadic noise in D9, the HV was dropped by 20 counts (now at 3600V). Commanding was at 20:57 UTC. This successfully quieted the noise. The noise was mainly fast counts, which cut drastically into the livetime.
- 2014 October 8: This detector has started to show some periodical spikes during last couple of days. Still is not clear what is their origin. It seems to be periodic with the orbit. So far no action taken.
- 2014 Oct 31: Elevated noise during the period of Oct 31 - Nov 2. The onset, as well as the abatement was sudden. No commanding was done and the noise returned to regular levels.
- On 2014 Jan 8, the rear fast threshold was raised since fast counts were eating up a lot of livetime.
15-008-17:45:50 /IDPUTABLE9 OFFSET=REARFASTDAC
15-008-17:46:04 /IDPULOAD VALUE=0x50 ;(was 0x45)
- Rear fast counts are high again, so we raised the rear fast threshold by 16 steps, in two sets of 8, on the BGS pass starting at ~3:30 PST. The new value is 0x60 (was 0x50). Fast rates as eyeballed from the realtime data were approx 58,000 (pre-adjustment), 12,000 (after 8 steps up), and 1600 (after 16 steps up). Livetime percentages were approx 60%, 90%, and 98%, respectively.
15-021-23:33:58 /idpudumptabl table=dibtbl9
15-021-23:34:03 /idputable9 offset=rearfastdac
15-021-23:34:34 /idpuload value=0x58
15-021-23:36:47 /idputable9 offset=rearfastdac
15-021-23:36:55 /idpuload value=0x60
D9 front slow LLD threshold history
D9 front fast LLD threshold history
D9 rear slow LLD threshold history
D9 rear fast LLD threshold history
| post 2014 anneal | 0x45
|
| 2014-Jan-08 17:46:04 | 0x50 (was 0x45)
|
| 2014-Jan-22 23:34:34 | 0x58 (was 0x50)
| 2014-Jan-22 23:36:55 | 0x60 (was 0x58)
|
D9 HV history
| post 2014 anneal | 3995 V
|
| 2014-Aug-20 | 3603V (was 3995V)
|
