Date of Award

Spring 2015

Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Ephraim Fischbach

Committee Chair

Ephraim Fischbach

Committee Member 1

Andrew S. Hirsch

Committee Member 2

John P. Finley

Committee Member 3

Virgil E. Barnes


We investigate experimental evidence for time-varying nuclear decay rates, in contrast to the widely-accepted view that nuclear decaying isotopes disintegrate at a constant rate unaffected by external conditions. We study several past cases of radioactive isotopes exhibiting annual periodicities in their decay rates, presumably related to the annual variation in Earth-Sun distance. Following recent indications of shorter-lived anomalies in 54Mn decay rates concomitant with an X-class flare in 2006, we attempt to design and develop a series of unique signal detection algorithms to identify regions of anomalous activity in a nuclear decay signal. With stringent threshold cut-offs and filtering processes, these regions are isolated as exhibiting statistically significant deviations from an expected exponential decay model. The isolated decay flags are compared to daily distributions of multiple solar indices associated with heightened flare activity. We present the findings from a 2 year period of data collection on 54Mn. Of the several computational checks performed to verify the validity of these results, none were able to produce values as good as those generated from the actual decay measurements.

Included in

Nuclear Commons