The readsorption of 4He atoms on a constantan heater surface was studied after flash desorption by the heat pulse technique. The replenishment of the desorbed film after the heat pulse was found to be essentially linear with the time between the pulses, reaching saturation at some critical value, trc, which strongly depended on the pressure in the vapor, Pg. With the help of kinetic theory for the flux of atoms striking a surface, the measured value of trc could be calibrated to give Pg. We have verified this formula directly and used it to measure pressures down to 10-9 Torr.
Bibliographical noteFunding Information:
* This work was supported ** BantreII Fellow.