Detector 4

From RHESSI Wiki

Revision as of 18:14, 23 August 2015

This page contains information about changes/issues for RHESSI detector 4 after the 2014 anneal. Detector updates from 2012-mid 2014 can be found here: Detector 4 anneal 2012

Notes

After the 2014 anneal, detector 4 is UNSEGMENTED.

• On May 21 starting at 19:24 UTC we raised up the Slow threshold for the Front segment.

15-141-19:24:10 start idib_chg_thrshld (4, FRONT, SLOW, 0x68)  --> Was 0x60
15-141-19:24:22 /IDPUDUMPTABL TABLE=DIBTBL4
15-141-19:24:22 /IDPUTABLE4 OFFSET=FRONTSLOWDAC
15-141-19:24:31 /IDPLOAD VALUE=0x68

• Raised front fast threshold due to elevated counts. This change reduced counts and increased livetime

2015-152-17:00:18 /IDPUTABLE4 OFFSET=FRONTFASTDAC
2015-152-17:00:31 /IDPLOAD VALUE=0x60  ; was 0x50

• On 2015 July 7, D4 front fast threshold was raised due to decreased livetime.

2015-188-18:48:17 /IDPUTABLE4 OFFSET=FRONTFASTDAC
2015-188-18:48:34 /IDPLOAD VALUE=0x70  ; was 0x60

• 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.

2015-191-19:21:17 /IDPUTABLE4 OFFSET=FRONTFASTDAC
2015-191-19:21:25 /IDPLOAD VALUE=0x80  ; was 0x70

• The front fast threshold was increased on July 24 2015 due to low livetime due to high fast rates. This action was effective in raising the livetime, to ~90%.

2015-205-17:22:21 /IDPUTABLE4 OFFSET=FRONTFASTDAC
2015-205-17:22:30 /IDPLOAD VALUE=0x90  ; was 0x80

• 2015-08-13: Front slow valid threshold was raised by 10 steps; trying to get the slow valid rates down.

 2015-225-16:45:08 /IDPUTABLE4 OFFSET=FRONTSLOWDAC
 2015-225-16:45:20 /IDPLOAD VALUE=0x80  ; was 0x70

• On Aug 20, 2015 the front fast threshold was raised, in two commands of 16 steps each, in order to lower fast rates and free up livetime. This was successful but probably needs to be repeated. Livetime rose from ~0% to ~50%. The D4 threshold should be raised again to further raise the livetime.

15-232-22:17:53 start idib_chg_thrshld (4, FRONT, FAST, 0xA0)
15-232-22:18:12 /IDPUDUMPTABL TABLE=DIBTBL4
15-232-22:18:12 /IDPUTABLE4 OFFSET=FRONTFASTDAC
15-232-22:18:25 /IDPLOAD VALUE=0xA0

15-232-22:19:13 start idib_chg_thrshld (4, FRONT, FAST, 0xB0)
15-232-22:19:23 /IDPUDUMPTABL TABLE=DIBTBL4
15-232-22:19:23 /IDPUTABLE4 OFFSET=FRONTFASTDAC
15-232-22:19:32 /IDPLOAD VALUE=0xB0

D4 front slow LLD threshold history

D4 front fast LLD threshold history

D4 rear slow LLD threshold history

D4 rear fast LLD threshold history

D4 HV history