Abstract
Calibration of laser measurement equipment requires the use of an accurate and stable source of power. Lasers are not generally suitable for this purpose. The Bureau of Radiological Health, Food and Drug Administration, has been supplied with two National Bureau of Standards C-Series Calorimeters which rely upon high accuracy D.C. electrical power substitution as a calibration reference. The NBS-supplied system is discussed. An alternate, moderate cost commercial electrical substitution calorimeter system is discussed with respect to its applicability and accuracy when performing laser measurement equipment calibration.