Date of Award
January 2015
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Physics & Astronomy
First Advisor
Ephraim Fischbach
Committee Member 1
Andrew Hirsch
Committee Member 2
Mark Haugan
Committee Member 3
Fuqiang Wang
Abstract
The aim of this work is to make an accurate determination of the half-life of $^{32}$Si as well as to investigate reported variations in nuclear decay rates. Primarily, we focus on a previous experiment at Brookhaven National Lab (BNL) \cite{BNL}, which measured the ratio of interwoven $^{32}$Si and $^{36}$Cl decays over a 4 yr period and reported unexplained annual periodicities. Utilizing the very same sources and shuffling apparatus, we have observed the decay of $^{32}$Si and $^{36}$Cl for more than 6,000 hours each, over the last $\sim 2$ yr, while recording $\sim 5\times 10^6$ individual environmental readings. The half-life of $^{32}$Si, which has been quoted between 101(18) yr and 330(40) yr, is redetermined by this data to be $159.4\textrm{ yr} \pm 1.9\textrm{ yr (statistical)} \pm 3.7\textrm{ yr (systematic) with } \chi^2_{DOF} = 1.01$. We have also observed a periodic signal in the $^{32}$Si/$^{36}$Cl ratio decay data, similar to that in the original experiment at BNL, which we analyze at length. Finally, a related topic concerning self-induced decay and its relationship to systematic dead-time corrections is presented.
Recommended Citation
Heim, Jordan, "The Determination of the Half-Life of Si-32 and Time Varying Nuclear Decay" (2015). Open Access Dissertations. 1415.
https://docs.lib.purdue.edu/open_access_dissertations/1415