BETA-SPECTRUM OF IN-115

Liquid scintillator solutions based on the solvent phenethyl alcohol are loaded with the salt indium trifluoroacetate to concentrations as high as 200 g In/1. Using a scintillator solution loaded with 51 g In/1 in a low background chamber with muon anticoincidence and Pb walls 20 cm thick, a β- decay spectrum from In115 is obtained and fitted with a sixth order polynomial in (Eendpoint-E)Eendpoint). From these data we find T12(In115)=4.41(25)×1014 yr and Eendpoint(In115)=482(15) keV. These low background experiments also show that indium loaded liquid scintillators are excellent neutron detectors. Their sensitivity for epithermal neutrons in particular is excellent. It is expected that these results will be useful in designing a solar neutrino capture detector of the type suggested by Raghavan. RADIOACTIVITY In115; measured T12, Eβ. In-loaded liquid scintillator, 90 keV FWHM at 390 keV. © 1979 The American Physical Society.