%A"Goldan, P. D." %A"Cahn, J. H." %A"Goldstein, L." %D1963 %I; Univ. of Illinois at Urbana-Champaign, IL (United States) %2Sponsor not identified %J[] %KPHYSICS, ABSORPTION, COLLISIONS, DECAY, DENSITY, ELASTICITY, ELECTRONS, ENERGY, FREQUENCY, GLOW DISCHARGES, HEATING, HELIUM, INTERACTIONS, LOW TEMPERATURE, MASERS, MICROWAVES, MOTION, PLASMA, RADIATIONS, STABILITY, THERMODYNAMICS %PMedium: ED; Size: Pages: 13 %TELECTRON ENERGY DECAY IN HELIUM AFTERGLOW PLASMAS AT CRYOGENIC TEMPERATURES %XStudies of decaying afterglow plasmas in helium were ined near 4 deg K by immersion in a liquid helium bath. By means of a Maser Radiometer System, the electron temperature was followed below 200 deg K. Guided microwave propagation and wave interaction techniques premit determination of election number density and collision frequencies for momentum transfer. Electron temperature decay rates of the order of 150 mu sec/p(mm Hg alpha 4.2 deg K) were found. Since thermal relaxation by elastic collisions should be some two orders of magnitude faster than this, the electrons appear to be in quasiequilibrium with a slowly decaying internal heating source. Correlation of the expected decay rates of singlet metastable helium atoms with the electron temperature decay gives good agreement with the present experiment. (auth) %0Conference %NCONF-364-3; AED-Conf-195-6; %1 %CUnited States %Rhttps://doi.org/ DTIE %GEnglish