Electronic alpha particle counter

A radon-222 alpha particle counter for detection of radon gas concentrations near the ground surface including an elongated tubular housing, an alpha particle permeable, visible light impermeable window, a semiconductor detector in spaced relation to said window, and a confined alpha particle permeable gas medium between said window and said detector, circuitry for counting alpha particle impulses, and means for attenuating moisture from said gaseous medium.

An alpha particle detection apparatus having an alpha particle path including an alpha particle permeable, light impermeable membrane, a water-tight gas filled space less than one inch wide, and a surface barrier semiconductor, and means for attenuating moisture from said gas filled space.

An alpha particle detection apparatus including an elongated tubular housing having an alpha particle entry and detection end, and solid state circuitry means contained in said housing for counting alpha particle impulses and converting them to a count representing signal, and count signal transmitting end, an annular closure ring at said alpha particle entry end in sealing engagement with said housing, an alpha particle permeable, visible light impermeable membrane across the end of said housing and retained thereon by said closure ring, an inwardly directed abutment in said tubular housing having an opening therethrough for passage of alpha particles, a surface barrier semiconductor detector secured against said abutment and spaced inwardly from said membrane and defining with said membrane, said housing and said closure a gas filled cavity permeable to alpha particles, and means including a shaped desiccant disposed in said cavity for attenuating moisture from said gas.

In combination in a nuclear particle counting device including an elongated tubular body closed at one end and having a thin nuclear particle permeable membrane at the other end thereof, a rigid perforated plate for supporting said membrane being in surface-to-surface contact with said membrane and having myriad holes therethrough of from 0.001 to 0.5 inch diameter, means for supporting said perforated plate in said one end of said device on the downstream side of said membrane opposite the side of said membrane exposed to pressure, said membrane and said perforated plate coacting to close said other end of said body, means carried in said body for detecting nuclear particles which permeate said membrane and said perforated plate, and means for counting said detected particles.