BARREL 2010 Test Campaign


A. flight 6 quicklook info



The second flight this year (payload A) was launched at about 21:00:53UT on 17 Dec 2010. This unit used different solar panels, a modified magnetometer (and a different magnetometer orientation), and no x-ray detector. Payload A battery temperature starting climbing beyond normal sunlight-induced variation around 05:00UT on 19Dec. A power disruption occurred near 08:07, resulting in loss of contact with the payload. CSBF cut down the payload through an independent cutdown system at 08:58UT. Following cutdown and landing, there have been multiple short contacts with the payload, in which it is apparent that the system has been power-cycling. balloon track

quick-look pdf plots from flight 6 of the test campaign



B. flight 5 quicklook info


The first flight this year (payload B) was launched at 21:44:36UT on 13 Dec 2010. The trip to ceiling was unusually slow, but the balloon is holding altitude nicely. It appears that there was a high voltage anomaly near 07:09UT on 14Dec 2010, after which the system seems quieter and has slightly lower gain. Magnetometer offsets are larger than expected. Power system continues to work nominally. Flight over: cut down at 00:02UT on 19 Dec 2010, prior to overflying Australian airspace. balloon track

quick-look pdf plots from flight 5 of the test campaign

detector effects of HV anomaly

A detector anomaly can be seen at high time resolution in the four fast spectrum channels (ch1, ch2, ch3, ch4). The lowest energy range shows two count rate spikes followed by a slow count rate decline. The decline is consistent with the HV supply oscillator shutting off and discharging---this takes several seconds, during which time the pmt gain drops. Lower pmt gain means we detect only the higher energy parts of the spectrum, where the flux is lower. Hence, the count rates drop, until we see nothing. When the output high voltage drops low enough, the oscillator restarts and pmt gain quickly recovers, so counts re-appear.

Uncalibrated slow spectra acquired from the files that started at 05:40:20 (red trace, before anomaly) and 08:36:11 (blue trace, after anomaly), show changes: the 511keV peak shifted left, corresponding to a lowering of the high voltage supply, and noise counts at the low energy end have decreased. The noise count change at the low end is consistent with the decreased level and fuzz in the low level discriminator rate counters.