The Synchrotron Ultraviolet Radiation Facility (SURF III) at the National Institute of Standards and Technology provides a unique research opportunity in precision measurement with its continuous and calculable radiation stretching from the soft x-ray to the far infrared. In response to the rapid development of ultraviolet photodetectors for applications from industrial photolithography to astrophysics, we have developed absolute measurements capabliity with high accuracy to characterize photodectors. The absolute measurements at SURF III are based on a high-accuracy liquid-helium cooled cryogenic radiometer for measuring the power of the dispersed radiation from the SURF III through a monochromator. Typical uncertainty for the measurement by cryogenic radiometer in the ultraviolet is better than 0.5%. Equipped with such tool, we were able to study a variety of ultraviolet detectors of their spectral responsivities, surface reflectivities and the effects of radiation damage. Due to the accuracy of these measurements, the internal quantum efficiencies of the photodetectors can be derived and theoretically modeled to provide information on the mechanism of photon detection.
Citation: Review of Scientific Instruments
Issue: No. 3
Pub Type: Journals
cryogenic radiometer, detector standards, electrical substitution, radiometry, responisvity, synchrotron radiation, UV detector