Summary: Spent the day characterizing the NaI detector. The cool bit is that the 32 keV peak from Cs137 is visible in the spectrum. It was distinguished from the background and the pedestal by subtracting a background spectrum from a spectrum with the source. With the background subtracted out, the peak was clearly visible. This is important because while the maximum predicted x-ray energy from the experiment is in the range of 150 keV, the radiation may be over a spectrum that contains lower energies. The smaller the energy we can detect, the better. It looks like the detector signal may not be linear with the PMT running at the high gain necessary to resolve the 32 keV peak. This isn’t entirely unexpected. Tomorrow lower gain tests will be run to see if the detector is any more linear at lower gains. Linearity in this case means can the calculated voltage per channel on the detector predict where other peaks in the spectrum are....