Radiation from probe surfaces bombarded by electrons

Metals in the form of small probe surfaces are held at a positive potential in the highly ionized region of a discharge (commonly a csesium discharge) and aider intense electron bombardment emit radiation. Photographic spectro- photometry measurements are made. Radiations at 7 volts from W, Al, Be, Ai alloyed with Cs, Th, and Pt are similar in intensity and intensity distribution. The spectral energy distribution on a wave-length scale is nearly constant between Q400 and 2,400 A with a radiation flux of about 20 ergs for a wave-length range of 1m and for a current density of 1 ampere per cm 2 . J (X) for Cu has a pronounced increase in the red and for silver a tenfold increase between 3,200 and 3,600 A.