Gain

To provide an indication of the gain, for each observation, the 10-35 keV pulse height spectra, which include the collimator silver line, from the top- and mid-layers (all detectors combined to provide good signal-to-noise) were fitted with a model consisting of a second order polynominal plus Gaussian emission line. The best-fit energy of the Gaussian is given in the database table and is accurate to approximately 0.5 keV. In addition, four plots were produced during the extraction of data. These show the pulse height spectra from 20 to 35 keV for the top- and mid-layers and for each detector in use (two detectors per plot; see table 1). An example of these plots is shown in figure 2. The plots are stored as images ( GRAPHICS INTERCHANGE FORMAT or GIF), and can be viewed with image manipulation programs (e.g. XV⁵) or browsers capable of displaying images (e.g. Netscape Navigator) to verify that the silver line is at the expected energy of 22.1 keV for individual layers. Individual plots may be missing if the detectors were excluded during the pipeline processing (e.g. because of electronic noise on detectors 5 & 6).