The Dosimetry Group operates a system capable of performing electron beam processing, which consists of a Van de Graaff electron accelerator and a sample scanning mechanism. One such application is in the area of radiation hardness testing of solar cells.
NIST irradiates solar cells that are manufactured by leading developers of high-efficiency solar photovoltaic cells for space applications. As part of the space-qualification process, the performance of these cells in a space environment must be validated. This validation process includes the characterization of the cells in terms of their resistance to radiation. It is important to learn how each new solar cell design performs in a radiation environment, and the electron beam processing of the samples conducted by NIST supplies the manufacturer with invaluable performance data in the development of these devices.
Several samples can be processed simultaneously by sweeping the samples back and forth under the electron beam using a 1D or 2D scanning mechanism. The incident electron fluence is determined by an onboard Faraday cup mounted to the scanner.