Taking the Scans necessary for the Calibration

For the detector calibration, you'll have to record a number of scans on the STXM 5 microscope. In each case, make sure the microscope chamber is covered properly with the black cloth to make sure no ambient light can cause additional signals on the detector.

Detector Map:

A map of the detector response function is acquired by scanning the detector over a pencil beam. With the zone plate and OSA removed, insert a 5 or 10 micron pinhole as sample and place it over a bright spot of the exit window. This forms a straight pencil beam. If the ZP is already aligned, it might be enough to remove the OSA and place the pinhole over a bright spot on the ZP window outside the ZP. It is important that you don't use the focused beam for this scan!

Then, center the detector over the pencil beam and record a detector scan. To include the whole detector, the field size must be greater than 1,200microns in both X and Y. The resulting scan will ideally look like in Fig. 15 if you look at the sum of all segments ("BF total").

Make sure you make good use of the detector's dynamic range by adjusting the dwell time and / or the slit settings such that the largest signal you measure in any segment is just below 6Volts. For that, in SM_GUI, set the Signal Type to "Raw Counts / mVolts", cycle through all segments, click on "Full Scale" and check the maximum (which is given in mVolts). Make sure none of the segments is in saturation!.

Figure 15: A detector map (sum of all segments)

Dark Scans:

Cover the microscope chamber with black cloth, keep the shutter closed (no x-rays) and record at least four piezo scans with different dwell times between 1 and 10ms. Make sure all silicon detector channels are recorded (which is set by default if the silicon detector is inserted). You could scan 100 $\times$ 100 pixels with a very small pixel size (1nm). All dark scans must have the same parameters except for the dwell time (at least, the number of pixels must be the same for all).

Remember the file names of the scans recorded above. As long as you have the files, you don't have to do the calibration on the microscope computer.