Tohban Report 2015-01-28

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Revision as of 20:35, 27 January 2015

Rear fast counts are high again, so we raised the rear fast threshold by 16 steps, in two sets of 8, on the 2015-01-21 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

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.

 21:57:13 UTC / D6 front slow threshold to 0x30 (was 0x0C).

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!

A spin-up was performed on Monday, Jan 26 from about 14.5 RPM to 14.97 between 20:29 and 22:06 UTC. There were no anomalies.

Decimation	Normal / Vigorous
Night time data (fronts)	On
Night time data (rears)	On
Require extra passes?	No
Requirement for moving pointer?	No
Attenuator operation	Normal

@@ Line 33: / Line 33: @@
 -021-23:36:55 /idpuload value=0x60
-* D6 has been showing some strange peaks in the spectrum.  We should keep an eye on this and try changing the slow front threshold to see if that affects it.
+* 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.
+:57:13 UTC / D6 front slow threshold to 0x30 (was 0x0C).
+* 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!
 == Other notes ==