Detector 6

From RHESSI Wiki

Revision as of 18:26, 1 April 2015

This page contains information about changes/issues for RHESSI detector 6 after the 2014 anneal. Detector updates from 2012-mid 2014 can be found here: Detector 6 anneal 2012

Notes

After the 2014 anneal, detector 6 began its reincarnated life as an unsegmented detector but segmented shortly after (see below).

• On 2014 August 14, the HV on D6 was raised to 4926V in an attempt to segment it. This was successful, and D6 now operates as a segmented detector. Since its segmentation is borderline as of Aug/Sept 2014, it commonly unsegments during and just after the SAA.

• On 2014 Jan 8, the rear fast threshold was raised since fast counts were eating up a lot of livetime.

 15-008-17:44:55 /IDPUTABLE6 OFFSET=REARFASTDAC
 15-008-17:45:18 /IDPULOAD VALUE=0x50           ;(was 0x45)

• * D6 has been showing some strange peaks in the spectrum; these are best seen as multiple lines (that drift) in spectrograms. On Monday, Jan 28 we raised the slow front threshold on D6 to ~10 keV and kept it there for a day before returning to the nominal ~3 keV. This is intended to see if the slow threshold affects the abnormal spectral lines.

 15-026-21:57:13 / D6 front slow threshold to 0x30 (was 0x0C).
 15-027-21:37:03 / D6 front slow threshold to 0x0C (was 0x30).

• D6 fast rates are a bit high (have been rising slowly over the past week). It would be a good idea to raise the front fast threshold a touch. I didn't want to do this at the same time as the slow threshold experiment!

• D6 front fast threshold was adjusted from default (0x22) due to increased rates, based on the above suggestion. Rates dropped from 3300 to 1250 when the change was made.

 15-030-00:19:54 /IDPUTABLE6 OFFSET=FRONTFASTDAC
 15-030-00:20:17 /IDPLOAD VALUE=0x30   ; was 0x22

• On 2015 February 27 Front Fast threshold was raised

15-058-21:41:11 /IDPUTABLE6 OFFSET=FRONTFASTDAC
15-058-21:41:44 /IDPLOAD VALUE=0x40 (was 0x30)

• Another raise to D6 front fast threshold on 2015 March 9:

 15-068-01:26:56 /IDPUTABLE6 OFFSET=FRONTFASTDAC
 15-068-01:27:07 /IDPLOAD VALUE=0x50

• On 2015 March 13 another raise was made to D6 front fast threshold and a raise of the rear fast threshold was made:

 15-072-22:04:01 /IDPUTABLE6 OFFSET=FRONTFASTDAC
 15-072-22:04:22 /IDPLOAD VALUE=0x60
 
 15-072-22:05:07 /IDPUTABLE6 OFFSET=REARFASTDAC
 15-072-22:05:17 /IDPLOAD VALUE=0x60

• Again 2015 March 17 D6 front fast threshold was increased:

 15-076-20:44:01 /IDPUTABLE6 OFFSET=FRONTFASTDAC
 15-076-20:44:14 /IDPLOAD VALUE=0x70

On 2015 March 20 D6 HV was dropped in two 10 step increments, twice. Also we attempted to lower the front fast threshold to 0x50, but changed this almost immediately when the live time dropped to 3%:

 15-079-21:10:49 /IHVDAC DETECTOR=6, VOLTAGE=243
 15-079-21:12:47 /IHVDAC DETECTOR=6, VOLTAGE=233

 15-079-22:49:23 /ihvdac detector=6, voltage=223
 15-079-22:50:44 /ihvdac detector=6, voltage=213

 15-079-22:52:39 /IDPUTABLE6 OFFSET=FRONTFASTDAC
 15-079-22:52:58 /IDPLOAD VALUE=0x60

 15-079-22:55:07 /IDPUTABLE6 OFFSET=FRONTFASTDAC
 15-079-22:55:19 /IDPLOAD VALUE=0x50

 15-079-22:55:53 /IDPUTABLE6 OFFSET=FRONTFASTDAC
 15-079-22:56:01 /IDPLOAD VALUE=0x70

On 2015 March 25 D6 HV was dropped in 20 steps.

15-084-22:45:15 /ihvdac detector=6, voltage=203
15-084-22:46:45 /ihvdac detector=6, voltage=193 (3750 V)

D6 front slow LLD threshold history

D6 front fast LLD threshold history

D6 rear slow LLD threshold history

D6 rear fast LLD threshold history

D6 HV history