Detector 3
From RHESSI Wiki
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15-232-22:16:41 /IDPLOAD VALUE=0x50 | 15-232-22:16:41 /IDPLOAD VALUE=0x50 | ||
| - | * By Aug 24, 2015 rear livetime was so low that the detector had entered "reverse mode" where fast rates are not fully shown, and so fast threshold changes give the opposite effect to that you might expect. (Light leak shows up as livetime peaks, not valleys, in this mode.) The rear fast threshold was raised in two jumps. The first raise apparently increased fast rates and worsened livetime (due to this "reverse mode") but the second raise was successful in bringing down the fast rates and restoring livetime. | + | * By Aug 24, 2015 rear livetime was so low that the detector had entered "reverse mode" where fast rates are not fully shown, and so fast threshold changes give the opposite effect to that you might expect. (Light leak shows up as livetime peaks, not valleys, in this mode.) The rear fast threshold was raised in two jumps. The first raise apparently increased fast rates and worsened livetime (due to this "reverse mode") but the second raise was successful in bringing down the fast rates and restoring livetime to ~64%. |
2015-236-20:45:42 /IDPUTABLE3 OFFSET=REARFASTDAC | 2015-236-20:45:42 /IDPUTABLE3 OFFSET=REARFASTDAC | ||
2015-236-20:45:54 /IDPLOAD VALUE=0x80 ; was 0x70 | 2015-236-20:45:54 /IDPLOAD VALUE=0x80 ; was 0x70 | ||
Revision as of 16:37, 26 August 2015
This page contains information about changes/issues for RHESSI detector 3 after the 2014 anneal. Detector updates from 2012-mid 2014 can be found here: Detector 3 anneal 2012
Contents |
Notes
Detector 3 is SEGMENTED following the 2014 anneal (yay!)
- 2014-Aug-26: D3 is suffering a lot from the known light leak problem. This does not affect the quality of the data but greatly reduces livetime at times when light leaks in through the cryostat port. To alleviate this problem, the G3 rear fast threshold was raised from 0x45 to 0x50 at 2014-238-19:22:56 UTC. This didn't seem to fix the problem.
- Another threshold change b/c of light leak:
14-241-18:34:11 /IDPUTABLE3 REARFASTDAC ;Load address 0x25CC 14-241-18:34:31 /IDPULOAD VALUE=0x60 ;Rear fast from ox50 to 0x60
- Front Fast threshold increase due to light leak. This lowered fast counts and increased livetime
2015-152-16:58:07 /IDPUTABLE3 OFFSET=FRONTFASTDAC 2015-152-16:58:16 /IDPLOAD VALUE=0x30 ; was 0x22
- The front fast threshold was increased on July 10 2015 due to low livetime due to high fast rates. This action was effective in raising the livetime.
2015-191-19:20:47 /IDPUTABLE3 OFFSET=FRONTFASTDAC 2015-191-19:20:58 /IDPLOAD VALUE=0x40 ; was 0x30
- On Aug 20, 2015 the front fast threshold was raised in order to lower fast rates and free up livetime. This was successful: Livetime rose from ~50% to >90%.
15-232-22:16:08 start idib_chg_thrshld (3, FRONT, FAST, 0x50) 15-232-22:16:30 /IDPUDUMPTABL TABLE=DIBTBL3 15-232-22:16:30 /IDPUTABLE3 OFFSET=FRONTFASTDAC 15-232-22:16:41 /IDPLOAD VALUE=0x50
- By Aug 24, 2015 rear livetime was so low that the detector had entered "reverse mode" where fast rates are not fully shown, and so fast threshold changes give the opposite effect to that you might expect. (Light leak shows up as livetime peaks, not valleys, in this mode.) The rear fast threshold was raised in two jumps. The first raise apparently increased fast rates and worsened livetime (due to this "reverse mode") but the second raise was successful in bringing down the fast rates and restoring livetime to ~64%.
2015-236-20:45:42 /IDPUTABLE3 OFFSET=REARFASTDAC 2015-236-20:45:54 /IDPLOAD VALUE=0x80 ; was 0x70
2015-237-00:03:38 /IDPUTABLE3 OFFSET=REARFASTDAC 2015-237-00:03:48 /IDPLOAD VALUE=0x90 ; was 0x80
D3 front slow LLD threshold history
| post 2014 anneal | 0x0C |
D3 front fast LLD threshold history
| post 2014 anneal | 0x22 |
| 2015-06-03 16:58:16 UTC | 0x30 (was 0x22) |
| 2015-07-09 19:20:58 UTC | 0x40 (was 0x30) |
| 2015-08-20 22:16:41 UTC | 0x50 (was 0x40) |
D3 rear slow LLD threshold history
| post 2014 anneal | 0x30 |
D3 rear fast LLD threshold history
| post 2014 anneal | 0x45 |
| 2014-08-26 19:22:56 UTC | 0x50 (was 0x45) |
| 2014-08-29 18:33:28 UTC | 0x60 (was 0x50) |
| 2015-08-24 20:45:54 UTC | 0x80 (was 0x70) |
| 2015-08-25 00:03:48 UTC | 0x90 (was 0x80) |
D3 HV history
| post 2014 anneal | 3995 V |
