Ballistic heat pulses in spin-polarized atomic hydrogen toT=200mK

Abstract

We have used a heater and bolometer to create and detect ballistic heat pulses of spin-polarized hydrogen atoms (Harrow-down). Energy can be effectively coupled from helium-covered walls to the Harrow-down gas without recombination. The energy loss coefficient of Harrow-down on /sup 4/He has been measured to be 0.2 +- 0.1. This technique can be considered as the generation of very-low-velocity atomic beams of Harrow-down, down to 200 mK.