Chandra Advanced CCD Imaging Spectrometer (ACIS) prototype calibration
Chandra Advanced CCD Imaging Spectrometer (ACIS) prototype calibration
CCDs (charge-coupled devices), in addition to making good optical light detectors for your digital camera also make good X-ray detectors. My senior thesis at the Massachusetts Institute of Technology (MIT) Center for Space Research under George Ricker and Mark Bautz involved studying the low-energy quantum efficiency of CCDs similar to those used on the Chandra X-ray Observatory. I used a fluorescent soft X-ray source producing K-shell emissions from elements in the C to Cl range (277-2622 eV). The X-ray source worked by bombarding targets with alpha particles. I measured the X-ray emission from the fluorescent targets using a small, thin-windowed proportional counter, a skill that came in handy later in graduate school. Unfortunately, one of the targets (polyvinyl chloride) had become "hot," emitting what appeared to be beta particles. These made large splotches on the CCD images, which interfered with the accuracy of the results. Even more unfortunately, I didn't figure out exactly what was going on with the PVC target until the day before my thesis was due! By the good graces of the MIT physics department, I was able to spend a few days tracing the possible nuclear reactions that led to the "hot" PVC target, finding that indeed alpha bombarded 37Cl was possible likely source of beta particles. I wrote everything up and only had nightmares about "that unfinished chapter" for a few weeks. Before starting my thesis, I worked on a UROP project in the same lab calibrating high activity 55Fe sources to study CCD degredation.
- High vacuum systems
- CAMAC crate electronics
- low-level CCD controllers
- Radioactive sources
Jeffrey P. Morgenthaler 2003-04-23
