The Determination of the Half-Life of Si-32 and Time Varying Nuclear Decay

The aim of this work is to make an accurate determination of the half-life of ³²Si 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 ³²Si and ³⁶Cl 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 ³²Si and ³⁶Cl for more than 6,000 hours each, over the last $\sim 2$ yr, while recording \sim 5\times 10⁶ individual environmental readings. The half-life of ³²Si, 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 } \chi²_DOF = 1.01. We have also observed a periodic signal in the ³²Si/³⁶Cl 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.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics & Astronomy

Year

2015

Author dc:creator

• Heim, Jordan

Contributors dc:contributor

• Ephraim Fischbach
• Andrew Hirsch
• Mark Haugan
• Fuqiang Wang

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/1415

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-2631