INFRARED OUTPUT FROM A COMPACT HIGH-PRESSURE ARC SOURCE

The radiant energy from a very small mercury are source has been measu red over the wavelength range 2-1000 mu m and compared with a globar a nd a standard mercury are source. As expected, in the far infrared the output is primarily from the are plasma and below 100 mu m from the f used quartz envelope, Due to its small surface area the envelope reach es a temperatures of similar to 1365 K and gives comparable brightness to a globar in the near and middle-infrared, except at the restrahlen bands of quartz near 9 and 22 mu m. In the region from 30-100 mu m th e new source output rises steadily compared with the globar, predomina ntly due to a reduction in emissivity of the latter. In the far-infrar ed the are temperature is similar to that of the standard mercury lamp with an effective temperature approaching 5000 K.