Observations of naphthalene scintillations due to tritium beta rays /

It seems desirable to report here some preliminary observations on the scintillations produced in commercial naphthalene by the beta rays from tritium and by the bremsstrahlung coming from tritium occluded in tantalum. Of immediate interest is the lower limit set on the conversion efficiency from beta ray to visible light energy. A small amount of gaseous tritium was put in direct contact with finely powdered naphthalene crystals in a 15 cu cm glass Kjeldahl flask, an identical flask but without tritium being used as a control, to find the direct action of the betas. A tantalum disk containing tritium occluded throughout its volume was placed near a solid piece of naphthalene to investigate the effect of soft x-rays since this is almost a pure source of such radiation. Both sources produced scintillations which were observed with a 1P21 photomultiplier, the pulses amplified by a Los Alamos Model 501 amplifier. The photomultiplier was not refrigerated. The rise time and total pulse length, easily observed on a 248A Dumont scope were respectively 0.05 microsecs and 0.2 microsecs. The gas concentration was not well known because the initially too high counting rates necessitated two depletions. jg p.2.Work performed at the Los Alamos Scientific Laboratory."Date Declassified: September 2, 1948.""AECD-2273; (LADC-552)."Includes bibliographical references (p. 3).It seems desirable to report here some preliminary observations on the scintillations produced in commercial naphthalene by the beta rays from tritium and by the bremsstrahlung coming from tritium occluded in tantalum. Of immediate interest is the lower limit set on the conversion efficiency from beta ray to visible light energy. A small amount of gaseous tritium was put in direct contact with finely powdered naphthalene crystals in a 15 cu cm glass Kjeldahl flask, an identical flask but without tritium being used as a control, to find the direct action of the betas. A tantalum disk containing tritium occluded throughout its volume was placed near a solid piece of naphthalene to investigate the effect of soft x-rays since this is almost a pure source of such radiation. Both sources produced scintillations which were observed with a 1P21 photomultiplier, the pulses amplified by a Los Alamos Model 501 amplifier. The photomultiplier was not refrigerated. The rise time and total pulse length, easily observed on a 248A Dumont scope were respectively 0.05 microsecs and 0.2 microsecs. The gas concentration was not well known because the initially too high counting rates necessitated two depletions. jg p.2.Mode of access: Internet