An IR Imaging and Spectral Diagnostic System for Alcator C-Mod

70572 In the Alcator C-Mod fusion experiment, increased plasma heating and current drive will heat the diverter plates, creating the possibility of damage. It is therefore important to monitor those structures, as well as the surrounding parts of the walls that cannot be seen directly through the ports. Infrared-transmitting optical fiber bundles could be used to carry images out of the device. However, these fibers have only recently been developed. Before building a diagnostic system, it must be determined whether the fibers will retain their characteristics in the hostile environment of the plasma chamber. Therefore, this project will first determine the effect, if any, of radiation on fiber transmission and also measure any spurious luminosity produced in the fiber by the plasma discharge. Then, the new diagnostic will be designed for fabrication and installation during Phase II. In Phase I, sample fibers will be left in the machine for an extended time and then the effect of cumulative damage on the transmission will be measured. Then the fibers will be observed during machine pulses to check for radiation-induced luminosity. Lastly, the new diagnostic will be designed. Commercial Applications and Other Benefits as described by the awardee: An infrared imaging capability that allows one to observe hard-to-access structures in hostile environments should have other applications in addition to fusion science. Potential users include power plants, chemical plants, and hospitals.