|revised 4/15/99, 5/3/99||back to HETG HSI Analyses|
To measure the QE depression value in the B-K image, a straight line was fit between subregions of the B-K projected LRF which were uneffected by the depression (asterisks in top panel). The ratio of measured counts to the line fit value was then fit to a horizontal line (nominally at 1.0) and a Gaussian depression (illegible center panel, replotted in lower panel).
Fitting results i ctr dctr hght dhght sig dsig area darea 1 2043.046 1.0697 -0.17 0.013 12.1442 1.2423 -2.67 -0.342 Cont= 1.00 dCont= 0.01 Chisq= 1.08The Gaussian "hght" of -0.17 corresponds to a QE depression value of 0.83, averaged over the events selected.
Setting the QE depression value to 0.83 (in hsi_qe_depress.pro) and using statistial creation of the missing events yields a good fit to just the straight line.
QE_DEPRESS = 0.830 : Candidates for correction: 87665 Candidates added: 2618 Fitting results i ctr dctr hght dhght sig dsig area darea 1 2043.184 0.7665 -0.09 0.036 1.6701 0.7082 -0.19 -0.110 Cont= 1.01 dCont= 0.00 Chisq= 1.33
The above analyses were carried out in the procedure hsi_B_tile_anal.pro.
This web page is: http://space.mit.edu/HETG/hsi/B-K_tile_anal.html
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