Beta ray back-scattering appts. - for thin film measurement using beta point source, aperture ring and geiger-mueller counter on adjustable mounting

摘要

Thin films are measured by beta ray backscattering. The measuring appts. includes a beta point source supported coaxially with an aperture ring and a Geiger-Muller counter. Axial spacing is adjustable using two axially movable partial tubes with fine adjustment. A locking arrangement is provided for the fine adjustment. The tubes are connected to the anode and cathode of the counter. The device is compact and formed as a readily replaceable unit. It can be accurately set for work with very small apertures.