The 0.8 counter (sometimes known as the Robinson counter) is an accurately
calibrated defined solid angle instrument. The detector is a 0.048 cm
thick CsI(Tl) scintillation crystal attached through a lightpipe to a
5 in (12.7 cm) electronmultiplier phototube. A three dimensional
central baffle combined with a large diameter outside aperture provides a
geometry factor which is independent of source position within a radius of
0.5 cm H2 gas fills the cavity to enable the alpha particles to
reach the detector without significant loss of energy.
Reference: Backscattering of Alpha Particles from Thick Metal Backings
as a Function of Atomic Weight. J.M.R. Hutchinson, C.R. Naas,
D.H. Walker, and W.B. Mann. Int. J. Appl. Radiat. Isotopes, 19,
517 (1968).
counter (sometimes known as the Robinson counter) is an accurately
calibrated defined solid angle instrument. The detector is a 0.048 cm
thick CsI(Tl) scintillation crystal attached through a lightpipe to a
5 in (12.7 cm) electronmultiplier phototube. A three dimensional
central baffle combined with a large diameter outside aperture provides a
geometry factor which is independent of source position within a radius of
0.5 cm H2 gas fills the cavity to enable the alpha particles to
reach the detector without significant loss of energy.
