Broad spectral electromagnetic radiation calorimeter: Centimeters to microns

Abstract

A specially designed calorimeter is presented capable of measuring total electromagnetic radiated power, in a single pulse mode over the complete spectral range, microwaves to far infrared. The device is assembled in the shape of a pyramid made from thin sheets of graphite absorber, giving it an operating range from centimeter wavelengths to the infrared region with an absorption coefficient of 0.99 at 1.25 cm wavelength. The calorimeter is capable of yielding a linear voltage response from less than 8 mJ up to at least 35 J with an overall sensitivity of 0.05 V/J. The device has the added feature of yielding information on waveguide modes. An example of the calorimeter use is presented.