Study of the dependence of Au-198 half-life on source geometry

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Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment 622,1 (2010) 93-96;


We report the results of an experiment to determine whether the half-life of Au-198 depends on the shape of the source. This study was motivated by recent suggestions that nuclear decay rates may be affected by solar activity, perhaps arising from solar neutrinos. If this were the case then the beta-decay rates, or half-lives, of a thin foil sample and a spherical sample of gold of the same mass and activity could be different. We find for Au-198, (T-1/2)(foil)/(T-1/2)sphere = 0.999 +/- 0.002, where T-1/2 is the mean half-life. The maximum neutrino flux at the sample in our experiments was several times greater than the flux of solar neutrinos at the surface of the Earth. We show that this increase in flux leads to a significant improvement in the limits that can be inferred on a possible solar contribution to nuclear decays. (C) 2010 Elsevier B.V. All rights reserved.

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