July 7th- Day 13

After a month of research all we have is... a little image!

Measuring the intensity would need a different approach rather than measuring the x-rays straight from the source because it would over saturate the detector. Instead, Alex told us to take 100 second spectra slowly building up layers in the filter. The Cu filter we had been using consisted of 8 layers. To take the spectra we needed to take apart the filter and run scans while still having a reasonable dead time (<10% optimal, but <30% is acceptable). After realizing we had been going about the wrong procedure and altering the current, we also realized our results made no sense. After getting assistance, Alex informed us that we needed to keep the current the same. However, we still were obtaining a high dead time while only using a few layers in our Cu filter. We would have needed to use an extremely low current, but at such a low current the tube is unstable so the results would not be accurate. Instead, Alex had us run different spectra using all 8 layers of the filter at a constant 50.7 kV. We were to increase the current by .05 mA intervals and take count readings. Plotting this data resulted in a linear line from which we could calculate the counts if the spectra was run at full power per 100 seconds. Dividing by 100 resulted in the number of counts per second at full power. This number divided by the transmission efficiency (taken from www.cxro.lbl.gov) resulted in the flux taking the Cu filter into account. The same mathematical procedure was then used to find the flux taking the air into account. After that, we placed an orange film really close to the optic to obtain a picture. With this image, one can see the defects of the crystal due to the various shading within the image. We then measured out 400mm from the optic at the Bragg angle of 14.22 degrees and obtained another image of the optic. This image was larger than our previous imaged and reflected with respect to a vertical axis.