Ultraviolet radiometry with synchrotron radiation and cryogenic radiometry.

Area of Science:

• Metrology
• Optics
• Materials Science

Background:

• Cryogenic radiometry offers the highest accuracy for primary detector-based standards.
• Synchrotron radiation provides a unique, continuous spectrum across a wide wavelength range.
• Accessing difficult spectral regions requires advanced radiometric techniques.

Purpose of the Study:

• To establish a new cryogenic radiometer-based facility for ultraviolet (UV) radiometry.
• To enable precise characterization of photodetectors and optical materials in the UV spectrum.
• To investigate UV radiation damage mechanisms in photodetectors.

Main Methods:

• Integration of a high-throughput normal incidence monochromator with an absolute cryogenic radiometer.
• Utilizing synchrotron radiation from the Synchrotron Ultraviolet Radiation Facility II.
• Performing absolute radiometric measurements from 125 nm to 320 nm.

Main Results:

• Demonstrated absolute spectroradiometric calibration of photodetectors.
• Characterized photodetector spatial responsivity, spectroreflectance, and internal quantum efficiency.
• Provided insights into UV radiation damage processes in photodetectors.

Conclusions:

• The new facility offers precise UV radiometric measurements for detector and optical material characterization.
• This capability advances the understanding of UV radiation effects on photodetectors.
• The facility supports diverse UV optical materials characterization applications.