A new experimental technique is developed to determine simultaneously the total hemispherical emittance, solar absorptance, and absorptance—emittance ratio for metals at cryogenic temperatures. The method compares the temperature response of thin metal samples to a sinusoidal perturbation of an imposed radiant intensity. Emittance data are presented for aluminum, copper, and 304 stainless steel over the temperature range 150–500 K. From the data, the applicability of the cyclic radiant intensity method is evaluated, and the problems associated with extending the method to temperatures below 150 K are discussed.
Ernie W. Spisz and John R. Jack, "Experimental Measurements of Thermal Radiation Properties by Cyclic Incident Radiation," Appl. Opt. 7, 2259-2263 (1968)