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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
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)
- April 7 2015: the front fast threshold was raised due to high fast rates that were significantly reducing livetime. This helped, but not a lot, so the action will probably be repeated soon.
15-097-19:56:35 /IDPUTABLE6 OFFSET=FRONTFASTDAC 15-097-19:56:45 /IDPLOAD VALUE=0x80 ; was 0x70
- April 9 2015: The front fast and the front slow threshold were raised up to recover the livetime and trying to reduce the noise on the slow valid counts.
15-099-17:32:59 /IDPUTABLE6 OFFSET=FRONTFASTDAC 15-099-17:33:11 /IDPLOAD VALUE=0xA0
15-099-21:17:16 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 15-099-21:17:27 /IDPLOAD VALUE=0x15
- On April 14 starting at 14:06 UT we made the next changes for detectors 6 trying to decrease valid counts on the Slow Front segment.
15-104-14:11:57 /IDPUTABLE6 OFFSET=FRONTFASTDAC 15-104-14:12:05 /IDPLOAD VALUE=0xA8 15-104-15:45:14 /IDPLOAD VALUE=0xB0 15-104-15:46:24 /IDPLOAD VALUE=0xB8 15-104-15:47:36 /IDPLOAD VALUE=0xB0
15-104-15:49:18 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 15-104-15:49:25 /IDPLOAD VALUE=0x1A 15-104-15:50:30 /IDPLOAD VALUE=0x1F 15-104-15:52:06 /IDPLOAD VALUE=0x15
- On May 21 starting at 19:23 UTC we made the next changes on Front Slow threshold:
15-141-19:25:36 start idib_chg_thrshld (6, FRONT, SLOW, 0x20) --> Was 0x15 15-141-19:25:46 /IDPUDUMPTABL TABLE=DIBTBL6 15-141-19:25:47 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 15-141-19:25:55 /IDPLOAD VALUE=0x20
- On May 26 we lowered the HV on detector 6 by 30 counts to a value of 1984 V. This change gave detector 6 the lowest voltage of all the detectors. G6 remained segmented through the pass.
2015-146-19:11:11 /IHVDAC DETECTOR=6, VOLTAGE=103 (1985 V)
We also increased the rear fast threshold on detector 6 by 0x08
2015-146-19:13:07 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-146-19:13:25 /IDPLOAD VALUE=0x68 ; was 0x60
- On 2015 July 7, D6 rear fast threshold was raised due to decreased livetime
2015-188-18:49:02 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-188-18:49:19 /IDPLOAD VALUE=0x70 ; was 0x68
- The rear fast threshold was changed on July 13 2015 due to dropping livetime in the rear:
2015-194-16:34:40 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-194-16:34:52 /IDPLOAD VALUE=0x80 ; was 0x70
- The rear fast threshold was changed on July 24 2015 due to low livetime. However, the change probably wasn't needed; the tohban hadn't noticed that a change had already been made a few days ago. The next tohban can reverse the change if desired.
2015-205-17:19:29 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-205-17:19:45 /IDPLOAD VALUE=0xB0 ; was 0xA0
- Aug. 24, 2015: Detector 6: Both front and rear fast thresholds were raised again. This successfully brought the livetime up to 75% in the front, but didn't really change anything in the rear. Another attempt was made with the rear fast threshold, but again no change. The slow threshold was also raised, which brought the slow rates down from 200k to 5k.
2015-236-20:44:59 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2015-236-20:45:10 /IDPLOAD VALUE=0xD0 ; was 0xB0
2015-237-00:02:53 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 2015-237-00:03:04 /IDPLOAD VALUE=0x25 ; was 0x20
2015-236-20:47:27 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-236-20:47:36 /IDPLOAD VALUE=0xC0 ; was 0xB0
2015-237-00:04:26 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-237-00:04:34 /IDPLOAD VALUE=0xD0 ; was 0xC0
- Detector 6 was showing elevated slow front rates. We made a HV change on August 28, lowering the voltage by 200V. The change made the slow front rates to decrease, but still the detector shows elevated slow front counts. On August 31, the rear fast threshold was raised to increase the detector livetime.
2015-240-17:32:26 /ihvdac detector=6, voltage=93 (from 1984 to 1789 V)
2015-243-18:01:47 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-243-18:01:56 /IDPLOAD VALUE=0xE0 ; was 0xD0
- The rear fast threshold was changed on Sep 9 2015 due to low livetime.
2015-252-17:53:05 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-252-17:53:18 /IDPLOAD VALUE=0xF0 ; was 0xF0
- On September 14 2015 we raised the rear fast threshold on D6 from 0xF0 to 0xFF and on September 15 we raised the RHESSI D6 front slow threshold from 0x25 to 0x30.
2015-257-17:35:39 /IDPUTABLE6 OFFSET=REARFASTDAC 2015-257-17:35:49 /IDPLOAD VALUE=0xFF ; was 0xF0
2015-258-17:09:29 /IDPUTABLE6 OFFSET=frontslowDAC 2015-258-17:09:38 /IDPLOAD VALUE=0x30 ; was 0x25
- 2nd October 2015: We increased the front slow thresholds, on detectors G3 and G6.
15-278-21:29:49 start idib_chg_thrshld(6, FRONT, SLOW, 0x40) ; was 0x30 15-278-21:29:53 /IDPUDUMPTABL TABLE=DIBTBL6 15-278-21:29:53 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 15-278-21:30:03 /IDPLOAD VALUE=0x40
- 5th October 2015: We increased the front slow thresholds G6
15-279-00:40:54 start idib_chg_thrshld (6, FRONT, SLOW, 0x50) ; was 0x40 15-279-00:40:58 /IDPUDUMPTABL TABLE=DIBTBL6 15-279-00:40:58 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 15-279-00:41:08 /IDPLOAD VALUE=0x50
- On October 8, the front fast threshold was raised to try and raise livetime. Prior to these changes, D6 front livetime was at ~20%. As the changes were made on a BGS pass, the D6 front fast rates fell from 100k to 9000, and the front LT rose to 78%, but then worsened a lot the next day, so more action was taken (see next item).
2015-281-21:49:49 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2015-281-21:49:59 /IDPLOAD VALUE=0xFF ; was 0xE0
- On October 12, the HV on detector 6 was dropped by 200V, to ~1600V. The reasons for this: D6 front livetime had plummeted, and the fast threshold was already maxed. I considered raising the slow threshold but concluded that this is unlikely to help the problem -- the previous two slow threshold raises did no good at all, spectrograms have shown that the event noise is across the energy spectrum, not exclusively at low energies, and right now it's clearly the high fast rates that are eating up all the livetime, not the slows. So something is necessary to reduce fast rates, and an HV drop is the only shot at that. This also may help some of the other issues with D6. A first look at the results indicates that this change was successful in reducing fast rates and raising livetime. Hooray! Livetime is at ~80% after the voltage drop. Continue to watch this detector.
2015-285-21:52:42 /IHVDAC DETECTOR=6, VOLTAGE=83 ;1593 V (was 1789 V)
- On October 28 in an attempt to lower the high reset rates and the front slow counts registered the HV on the detector was changed to ~1397.
2015-301-20:28:46 /ihvdac detector=6, voltage=73
- November 11, front slow threshold lowered from 0x50 to 0x40. The noise appears
relatively flat at those values, and we shouldn't experience too much additional noise counts.
2015-318-07:03:56 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 2015-318-07:04:07 /IDPLOAD VALUE=0x40 ; was 0x50
- 2015 December 10 & 12, front slow threshold lowered in an attempt to recover energy spectrum before GRIPS.
2015-344-19:58:19 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 2015-344-19:58:28 /IDPLOAD VALUE=0x30 ; was 0x40
2015-346-00:33:12 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 2015-346-00:33:22 /IDPLOAD VALUE=0x20 ; was 0x30
- 2016 January 8: The slow front threshold was increased from 0x30 to 0x80.
2016-008-01:32:23 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 2016-008-01:32:32 /IDPLOAD VALUE=0x80 ; was 0x30
- 2016 January 13, 15: We dropped the D6 HV to 500 V, to reduce noise and see if any spectrum could be recovered. No luck there, so on 15 january, we dropped the HV to 200 V. D6 desegmented and began to fill the memory. We raised the HV back to 500 V, and turned events off.
2016-013-23:02:09 /ihvdac detector=6, voltage=28 ; 500 V
2016-015-01:41:44 /ihvdac detector=6, voltage=11 2016-015-23:40:07 /ITMOFF VALUE=DIB6 ; off permanently 2016-015-23:40:25 /IHVDAC DETECTOR=6, VOLTAGE=28 ; 500 V
Post 2016 anneal
- This detector was turned on on 26 January 2017
- On 9-Feb-2017, the front fast threshold was raised from 0x70 to 0x80
2017-039-20:11:12 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2017-039-20:11:21 /IDPULOAD VALUE=0x80 ; was 0x70
- On 21-Feb-2017, front fast threshold was raised from 0x80 to 0x90
17-052-17:21:46 start idib_chg_thrshld(6,FRONT,FAST,0x90) ; was 0x80 17-052-17:22:22 start show_temps_avg 17-052-17:22:40 CP1: 152.6 K 17-052-17:22:40 CP2: 151.2 K 17-052-17:22:40 CT1: 127.9 K 17-052-17:22:40 CT2: 126.1 K 17-052-17:22:40 TST: 189.0 K 17-052-17:22:40 cp1 - ct1 = 24.61 K 17-052-17:22:40 Cryo Power: 75.4 W 17-052-17:22:40 Cryo Accel: 12.1 mG
- On May 15 at 17:50 we lowered the HV from ~3400V to ~2000 V as an experiment to increase the Livetime. The experiment worked well.
2017-135-17:50:10 /ihvdac detector=6, voltage=103 ; 2000 V
- 16 August 2017, raised front slow threshold to reduce low energy noise
17-228-19:57:37 start idib_chg_thrshld(6,FRONT,SLOW,0x1C) 17-228-19:57:41 /IDPUDUMPTABL TABLE=DIBTBL6 17-228-19:57:41 /IDPUTABLE6 OFFSET=FRONTSLOWDAC 17-228-19:57:48 /IDPULOAD VALUE=0x1C
- On 27-sep-2017, the front fast rate threshold for detector 6 was lowered to 0x20, in an attempt to set the threshold to such a low value that individual fast rate counts would not be distinguished, thus reducing the fast rates and increasing live time. This was not successful, and the threshold was raised back to 0xFF.
Here are the command times (UTC):
2017-270-19:33:14 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2017-270-19:33:24 /IDPULOAD VALUE=0x80 ; was 0xFF
2017-270-19:34:03 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2017-270-19:34:08 /IDPULOAD VALUE=0x40
2017-270-19:34:45 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2017-270-19:34:50 /IDPULOAD VALUE=0x30
2017-270-19:35:30 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2017-270-19:35:35 /IDPULOAD VALUE=0x20
2017-270-19:36:21 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2017-270-19:36:29 /IDPULOAD VALUE=0x10
2017-270-19:37:30 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2017-270-19:37:35 /IDPULOAD VALUE=0x00
2017-270-19:38:14 /IDPUTABLE6 OFFSET=FRONTFASTDAC 2017-270-19:38:18 /IDPULOAD VALUE=0xFF
- 3 November 2017: Rear fast threshold raised to 0xFF
17-307-16:32:54 start idib_chg_thrshld(6,rear,fast,0xFF) , was 0x60 17-307-16:32:58 /IDPUDUMPTABL TABLE=DIBTBL6 17-307-16:32:58 /IDPUTABLE6 OFFSET=REARFASTDAC 17-307-16:33:08 /IDPULOAD VALUE=0xFF
D6 front slow LLD threshold history
|post 2014 anneal||0x0C (after segmentation)|
|2015 Jan 26 21:57:13 UTC||0x30 (was 0x0C)|
|2015 Jan 27 21:37:03 UTC||0x0C (was 0x30)|
|2015 Apr 09 21:17:27 UTC||0x15 (was 0x0C)|
|2015 Apr 14 15:49:25 UTC||0x1A (was 0x15)|
|2015 Apr 14 15:50:30 UTC||0x1F (was 0x1A)|
|2015 Apr 14 15:52:06 UTC||0x15 (was 0x1F)|
|2015 May 21 19:25:36 UTC||0x20 (was 0x15)|
|2015 Aug 25 00:03:04 UTC||0x25 (was 0x20)|
|2015 Sep 15 00:17:09 UTC||0x30 (was 0x25)|
|2015 Oct 02 21:29:49 UTC||0x40 (was 0x30)|
|2015 Oct 05 00:40:54 UTC||0x50 (was 0x40)|
|2015-11-14 07:04:07 UTC||0x40 (was 0x50)|
|2015-12-10 19:58:19 UTC||0x30 (was 0x40)|
|2015-12-12 00:33:22 UTC||0x20 (was 0x30)|
|2016-01-08 01:32:32 UTC||0x80 (was 0x30)|
|post 2016 anneal||0x68|
D6 front fast LLD threshold history
|post 2014 anneal||0x22 (after segmentation)|
|2015-Jan-30 00:20:17||0x30 (was 0x22)|
|2015-Feb-27 21:41:44||0x40 (was 0x30)|
|2015-Mar-09 01:27:07||0x50 (was 0x40)|
|2015-Mar-13 22:04:22||0x60 (was 0x50)|
|2015-Mar-17 20:44:14||0x70 (was 0x60)|
|2015-Mar-20 22:52:58||0x60 (was 0x70)|
|2015-Mar-20 22:55:19||0x50 (was 0x60)|
|2015-Mar-20 22:56:01||0x70 (was 0x50)|
|2015-Apr-07 19:57||0x80 (was 0x70)|
|2015-Apr-09 17:33||0xA0 (was 0x90)|
|2015-Apr-14 14:12||0xA8 (was 0xA0)|
|2015-Apr-14 15:45||0xB0 (was 0xA8)|
|2015-Apr-14 15:46||0xB8 (was 0xB0)|
|2015-Apr-14 15:48||0xB0 (was 0xB8)|
|2015-Aug-24 20:45:10||0xD0 (was 0xB0)|
|2015-Sep-21 19:47:33||0xE0 (was 0xD0)|
|2015-Oct-08 21:49:59||0xFF (was 0xE0)|
|post 2016 anneal||0x40|
|2017-Feb-08 20:11:21||0x80 (was 0x70)|
|2017-Feb-21 17:22:22||0x90 (was 0x80)|
|2017-Feb-28 20:49:32||0xB0 (was 0x90)|
D6 rear slow LLD threshold history
|post 2014 anneal||0x30 (after segmentation)|
|post 2016 anneal||0x30|
D6 rear fast LLD threshold history
|post 2014 anneal||0x45 (after segmentation)|
|2015-Jan-08 17:45:18||0x50 (was 0x45)|
|2015-Jan-08 17:45:18||0x50 (was 0x45)|
|2015-Mar-17 22:05:17||0x60 (was 0x50)|
|2015-May-26 19:13:07||0x68 (was 0x60)|
|2015-Jul-07 18:49:19||0x70 (was 0x68)|
|2015-Jul-13 16:34:52||0x80 (was 0x70)|
|2015-Jul-29 17:19:45||0xB0 (was 0xA0)|
|2015-Aug-24 20:47:36||0xC0 (was 0xB0)|
|2015-Aug-25 00:04:34||0xD0 (was 0xC0)|
|2015-Aug-31 18:01:56||0xE0 (was 0xD0)|
|2015-Sep-09 17:53:18||0xF0 (was 0xE0)|
|2015-Sep-14 17:35:49||0xFF (was 0xF0)|
|post 2016 anneal||0x45|
|2017-Nov-03 16:32:54||0xFF (was 0x60)|
D6 HV history
|post 2014 anneal||4510 V (unsegmented)|
|2014-Aug-14 03:40 UTC||4926 V (was 4510 V) (segmented)|
|2015-Mar-20 21:12 UTC||4500 V (was 4926 V)|
|2015-Mar-20 22:50 UTC||4142 V (was 4500 V)|
|2015-Mar-25 22:47 UTC||3750 V (was 4142 V)|
|2015-May-26 19:11 UTC||1985 V (was 2573 V)|
|2015-Aug-28 17:32 UTC||1789 V (was 1985 V)|
|2015-Oct-12 21:52:42 UTC||1593 V (was 1789 V)|
|2015-Oct-28 20:28:46 UTC||1397 V (was 1593 V)|
|2016-Jan-13 23:02:09 UTC||500 V (was 1000 V)|
|2016-Jan-15 01:41:44 UTC||200 V (was 500 V)|
|2016-Jan-15 23:40:25 UTC||500 V (was 200 V)|
|post 2016 anneal||0V|
|2016-Mar-01 12:37:00 UTC||3480 V|
|2017-May-15 17:50:10 UTC||2000 V (was 3400 V)|