Date: Wed, 30 Jun 2004 12:07:58 +0200 Subject: JEM-X2 activation Folks, Now all the data are in from the JEM-X2 re-activation. The results are more or less as expected. The gain started out low, as in the previous re-activation. It was important to run for a full orbit, as the gain only reached the fully stable level after about 1 day, partly due to the lower initial temperature after eclipse. The stable gain level reached, adjusted for HV setting and temperature, is about 7% higher than during the Crab calibration in orbit 170. This is somewhat unexpected, as we presumed the gain increase only to proceed with the HV on. There was a variable hot spot causing a stripe in the JEM-X2 shadowgram around X=203. The activity of this hot spot stopped after about 30 hours of operation. We believe this hot spot activity to be related to the hardware trigger spikes that were observed during orbit 170. During orbit 170 we were operating with different selection criteria, effectively filtering out the events from the accepted events (leaving no clues in the data about the location of a hot spot). The opening of the selection criteria below PHA 115 were in orbit 208 letting in some of these events, which would otherwise fall on the criteria of 'low signal in the back-plane'. However, the average increase in the background level during the hot spot activity was less than 5 c/s and did not change the TM load significantly. The events must of course be filtered out in the science analysis. The good news is that the hot spot activity seemed to stop after 30 hours (aside from a few very, very faint and short episodes towards the end of the orbit). The data gathered in this session were very valuable and we should discuss the lessons learned. Søren Søren Brandt wrote: > > Folks, > > The JEM-X2 activation in rev. 208 is proceeding more or less as > expected. > There seems to be a hot spot on an anode strip around RAWX 203 causing > a variable excess background in the low energy band. > The gain is increasing as during the last activation, but following > a path a bit different due to the post-ecclipse thermal environment. > > Søren > > Salma.Fahmy@esa.int wrote: > > > > Dear All, > > > > To clarify, JEM-X2 will be activated in revolution 208, but not in 207. > > > > Best regards, > > Salma > > > > |--------+-----------------------> > > | | Michael | > > | | Schmidt | > > | | | > > | | 24/06/2004 | > > | | 09:43 | > > | | | > > |--------+-----------------------> > > >----------------------------------------------------------------------------| > > | | > > | To: Salma Fahmy | > > | cc: | > > | Subject: JEM-X2 activation in orbit 207 | > > >----------------------------------------------------------------------------| > > > > ----- Forwarded by Michael Schmidt/esoc/ESA on 24/06/2004 09:43 ----- > > |--------+-----------------------> > > | | Søren Brandt | > > | | | > > | | | > > | | 24/06/2004 | > > | | 09:40 | > > | | | > > |--------+-----------------------> > > >----------------------------------------------------------------------------| > > | | > > | To: ISDC shift team | > > | cc: Astrid Orr , Michael Schmidt | > > | , Peter Kretschmar | > > | , nl@dsri.dk, carl@dsri.dk | > > | Subject: JEM-X2 activation in orbit 207 | > > >----------------------------------------------------------------------------| > > > > Dear shift team, > > > > JEM-X2 will be activated during rev. 207 to monitor its performance. > > We consider this a routine operation and do not plan any real time > > monitoring by being present at ISDC or MOC. We will perform the > > off-line analysis of the Instrument Station data here in Copenhagen. > > However, if anything unusual seems to happen, please contact me at > > any time on +45 2326 5184. > > > > Søren Brandt