UHV Microbalance and Quartz Oscillator at Low Temperatures

Abstract

The intensities of beams of rubidium atoms were determined simultaneously by two independent methods with a magnetically compensated microbalance and with a resonating quartz oscillator, the latter serving as the pan of the microbalance. Both systems were operating at 180 K inside a cooled glass Dewar. Taking into account the temperature changes of the weighing ensemble during deposition caused mainly by the condensation of Rb atoms and the warming up of the surrounding Dewar, the Rb atom beam intensities, determined by the microbalance and independently by the frequency shift of the resonating quartz, agree to within 2%. In a separate experimental setup the measurements of the Rb atom beam intensities with a calibrated Pt-ionization foil and with the quartz oscillator at 81 K agree also to within 2%.