RESIK & Diogeness NEWS
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(Week 26 - Week 30, 2003, 23 Jun - 27 Jul)
In the display above (click to enlarge), the solar X-ray fluence seen by RESIK (black points) is plotted atop GOES red line. No RESIK spectra are available yet.
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Operation mode: |
1 s DGI has been used.
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Calibrations made: |
No calibrations made
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ADS Settings: |
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| (ORD1) HV: Det. A - 1480 V, Det. B - 1419 V. | (ORD3) HV: Det. A - 1389 V, Det. B - 1328 V. | ||||||
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Channel |
l Band |
ADS |
Channel |
l Band |
ADS | ||
| #1 | #2 | 3.37 - 3.88 Å | 115 - 195 | #1 | #2 | 1.16 - 1.29 Å | 55 - 110 |
| #2 | #0 | 3.82 - 4.33 Å | 75 - 170 | #2 | #0 | 1.27 - 1.44 Å | 80 - 160 |
| #3 | #3 | 4.31 - 4.89 Å | 170 - 250 | #3 | #3 | 1.44 - 1.63 Å | 90 - 160 |
| #4 | #1 | 4.96 - 6.09 Å | 145 - 205 | #4 | #1 | 1.65 - 2.03 Å | 135 - 200 |
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 spectroscopic notation
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Note, that the link to the catalogue page is now: http://www.cbk.pan.wroc.pl/resik_catalogue.htm.
RESIK Status After Recovery of Technical Part
As promised, here we
update the instrument status. We have been waiting for some good news to come,
and this caused present Newsletter to cover weeks 26 - 30.
These were quite busy months for the Wroclaw
RESIK team, as we have been analyzing the instrument electronic construction and operation to the very last
piece and byte in order to understand the reason of the 23rd May sudden failure.
As we understand now, the failure was due to fatal malfunction of the
secondary power unit, we have been using since March 14 (see Weekly 10,
2003). We
have made numerous following checks over the last two months in order to
investigate this backup power supply and recently concluded that the unit is dead indeed.
No further checks of backup power supply health are planned before the end of
2003. The primary power supply unit did not show further signs of ailing since
March, and the trend to lower the supplied voltage vanished. At present the
necessary voltages are provided as specified for ± 12V, however, instead of
having 5 V, the unit supply ~4.2 V to the spectrometer electronics. This is
enough for the HV power supply to be activated and so called technical cards
to function as specified.
Also, the processing of the signals from the detectors appears to work fine (i.e. position
encoding) so the spectra are being build-up, however they can
not be formatted and send to telemetry as the responsible microprocessor
cannot load its loading programme.
In the following Figures, we will show some of the present signals received
from RESIK.
Figure 1. The comparison of PHA analysis of solar signal before failure (upper) and at present. The "worst case" is shown (detector A) for which the change is larger. See the Table for more numbers.
Figure 2. Plot of the temperature (°C) - time behaviour as recorded within RESIK. The modulation seen is due to variations of the satellite orbital position (i.e. day/night).
The missing "good health" signal from the science microprocessor caused that the entire spectrometer has been seen as "dead" by the main computer COMP, since no appropriate response has been received. However, some patchy responses observed milliseconds after the contact attempt, lead us to believe that not all is lost. We (Mirek Kowalinski) started to modify step by step the RESIK main operational programme in order to bring down the instrument health info. In this respect it has been very helpful that Witold Trzebinski just finished construction of full backup RESIK electronic hardware including the computer and spectrometer (except detectors and front-end electronics). He succeeded to contact with the initial loader of RESIK ground computer from the keyboard and reproduced the full path of the signal down to Russian SSNI (mockup) acceptance. Using this backup unit, it has been possible to check on the ground all modifications to the RESIK operational programme. On July 29, 2003 the last stable version of the programme has been uploaded, resulting in RESIK technical part resuming operations (Dump No. 11188). With this programme RESIK acts now as X-ray broad-band four-channel photometer (in first order reflection), taking the measurements of solar integral fluence in the wavelength bands as indicated for the ORD1 mode (see Table above). The measurements are being made each second. Example of the RESIK record and GOES lightcurve is shown at the top.
Inspection of the PHA signal, namely the position of the peak due to solar-induced Si crystal fluorescence shows that the peaks have moved to higher bins and widened between March and present. This is shown in the Table.
This change is due to the falling level of
low voltage power supply which is over-corrected by the HV power supply unit (since
March, the 5 V level dropped from level=20 to 15). This over-correction caused
the HV to became higher, which caused the fluorescence peak on the PHA to move
up. The variation is the most substantial for detector
A.
We will closely look for the future variation of the PHA position, and try to
optimize again the settings for the ADS in order to select the solar signal in
the way as it has been done before the failure.
Prepared by: Janusz Sylwester js@cbk.pan.wroc.pl and Mirek Kowalinski mk@cbk.pan.wroc.pl
The report presented has been done in "real time" and so it may contain jargon, blunders, or trivialities. We do not have also an English native speaker in our Wroclaw group!
We would be happy to discuss problems mentioned above in more details if necessary.
RESIK data are in the open public domain and can be requested from: http://surfwww.mssl.ucl.ac.uk/surf/data_request.html.
Previous RESIK_weekly notes are in the archive: http://www.cbk.pan.wroc.pl/resik_archive.htm
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