July 21st- Day 17

Flux. Questions. Germanium. Fire drill. Heatwave. BBQ.

After fitting the intensity data we plotted in matlab, we used the equation of the line to estimate the number of counts at full power (50 keV and 0.6 mA) <2712700 counts>. Because we took 100 second spectra, we then divided this number by 100 to get the estimated counts per 1 second at full power <27127 counts>. We then took this number and divided it by the transmission of air (0.62670) found using the www.cxro.lbl.gov website <43285.46>. Then to account for varying spot sizes, we had to divide by 16 because the area of the spot size we obtained was 16 times smaller than the area of the 200 micron spot size pin hole we had taken the spectra with <2705.341>. This flux calculation is significantly smaller than the flux we had previously calculated using the optic and copper filter. This was the expected result. Because the detector has such a high efficiency, taking the detector's transmission efficiency into account has no significant contribution to the flux. This is because all of the x-rays pass through the Be window.
We got a chance to ask Alex a bunch of questions. What we had been doing for the past month or so was characterizing the optic, Si(111) to be specific. This optic would stay at XOS to be used as a reference when making other optics. However, similar optics would be sent to customers, companies like Jordan Valley. JV could be using the optic as a part of their semiconductor for some imaging purpose. Their semiconductor might use multiple beams to collect different data. Alex wasn't too sure sure exactly what they were using the optic for. We used a monochromatic convergent beam to take measurements. Applications could include anything from edxrf or wdxrf to imaging. Based on the customers' desired spot size, energy, and total working distance, XOS picks out a crystal that will fit the parameters. Crystals will accept different energies based on their lattice structure. The lower the spot size, the lower the acceptance. Graphite, if used as a crystal, accepts a much wider range of energies when compared to silicon. As a result the resolution of graphite suffers. When a crystal is bent it can accept an even greater range of energies. With our Si(111) optic, the divergence was large because of the convergent beam. A parallel beam would have a divergence of around 0.01 degrees.
We also started setting up a new set up for Ge(111). The Bragg angle is 15.89 degrees and the IFD/ OFD is 123mm. However, we would need a new source/ power supply that would not be available until next week, so we could not get very far. 

*Numbers in brackets represent the calculated number after doing the described operations.