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(Week 07, 2003, 10 Feb. - 16 Feb.)
In the display above (click to enlarge), the solar X-ray fluence seen by RESIK (black points) is plotted atop GOES red line. Only periods with good spectral measurements are indicated. The total number of good spectral measurements is given in the title line.
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Operation mode: |
Since 01 February 2003 the DGI rate has been set to 4 s. '3rd order reflections' (ORD3) is used as stand by mode. 3rd order measurements are indicated on the main catalogue page http://www.cbk.pan.wroc.pl/resik_catalogue.htm (cf. green boxes).
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Calibrations made: |
No calibrations made
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ADS Settings: |
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| (ORD1) HV: Det. A - 1450 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 | 55 - 110 | #1 | #2 | 1.16 - 1.29 Å | 110 - 230 |
| #2 | #0 | 3.82 - 4.33 Å | 80 - 165 | #2 | #0 | 1.27 - 1.44 Å | 110 - 230 |
| #3 | #3 | 4.31 - 4.89 Å | 90 - 160 | #3 | #3 | 1.44 - 1.63 Å | 110 - 230 |
| #4 | #1 | 4.96 - 6.09 Å | 135 - 200 | #4 | #1 | 1.65 - 2.03 Å | 140 - 230 |
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 spectroscopic notation
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Data gaps due to missing telemetry: ~ 3.8 h.
Note, that the link to the catalogue page is now: http://www.cbk.pan.wroc.pl/resik_catalogue.htm.
RESIK and GOES
It is by fortuitous coincidence that RESIK spectrometer covers nearly entire spectral ranges observed routinely by GOES X-ray sensors, i.e. well known 1 Å - 8 Å and 1 Å - 4 Å bands. Records of global solar flux variations in these two bands are available each minute on line from NOAA Boulder (http://www.sel.noaa.gov/rt_plots/xray_1m.html). The GOES X-ray fluxes are measured using very stable detectors and serve as a photometric reference for solar purposes.
Having this in mind, we tried to
cross-check, the stability of RESIK X-ray proportional detectors, by comparing
the integral fluxes measured by RESIK with those measured at the same time by
GOES instruments. In the Figures below, we show examples of such comparison
made for selected strong flares commonly observed. Selected events sample the
entire period of RESIK observations around 20 months long by now.
Figure 1. „Correlation plots” showing the relation of RESIK total count rate observed in Channels #1 and #2 (detector A and B respectively) and the level of GOES flux observed in 1 Å – 8 Å band. For comparison, the „dependence” for so-called qualified events is displayed. The qualified events represent this part of RESIK X-ray photons which contributes to the solar spectrum observed in the appropriate channel. The points have been plotted for the decay phase of 3rd August 2002 X-class flare (see page http://www.cbk.pan.wroc.pl/2002/RDC_200208/resik_prC_05628_20020803_1736.png in RESIK Catalogue for more information).
Figure 2. The same as in Figure 1 but for seven strong flares (decay phases only), representative for various stages of RESIK operation. The selected events cover the time interval since 25th August 2001 to 1st February 2003. The colour of the points plotted is different for each event. The down-bend seen on the „qualified events” dependence is due to saturation effects within the on-board position encoding electronics. It takes time (~30 μsec) to assign the arrival positions (wavelengths) for the incoming X-ray photons.
There are several effects clearly seen from the plots presented.
• The dependences for „all counts” form the single line for all flare decays. This inform us that the detectors characteristics have been stable for the last ~20 months.
• The „all counts” lines are placed at the very similar level for detectors A and B. This indicates that their responses are quite similar (if not identical).
• The „qualified events” line drops down around GOES level X. This means that no spectra can be recorded by RESIK (in the first order of reflection) for flares above this threshold.
• The dead-time of the position encoding electronics is longer for detector A, as the observed drop for this detector is more abrupt.
We hope, that these position sensitive detectors developed at MSSL, UK (http://www.mssl.ucl.ac.uk/www_detector/propcounters/report95.htm) will serve the RESIK project as long as analogous detectors served the Yohkoh BCS spectrometer.
Report prepared by: Barbara Sylwester bs@cbk.pan.wroc.pl and Janusz Sylwester js@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
Page made on 21 February 2003 by: Anna Kepa ak@cbk.pan.wroc.pl and Jarek Bakala jb@cbk.pan.wroc.pl
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