{"id":{"repo_id":"purdue-thes","oai_identifier":"oai:docs.lib.purdue.edu:open_access_dissertations-2631"},"canonical_url":"https://search.dev.ndltd.org/etd/purdue-thes/oai:docs.lib.purdue.edu:open_access_dissertations-2631","repository":{"repo_id":"purdue-thes","name":"Purdue University","base_url":"https://docs.lib.purdue.edu/do/oai/"},"display":{"title":"The Determination of the Half-Life of Si-32 and Time Varying Nuclear Decay","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.","abstract_html":"The aim of this work is to make an accurate determination of the half-life of <span class=\"etd-inline-math\"><sup>32</sup></span>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 <span class=\"etd-inline-math\"><sup>32</sup></span>Si and <span class=\"etd-inline-math\"><sup>36</sup></span>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 <span class=\"etd-inline-math\"><sup>32</sup></span>Si and <span class=\"etd-inline-math\"><sup>36</sup></span>Cl for more than 6,000 hours each, over the last $\\sim 2$ yr, while recording <span class=\"etd-inline-math\">\\sim 5\\times 10<sup>6</sup></span> individual environmental readings. The half-life of <span class=\"etd-inline-math\"><sup>32</sup></span>Si, which has been quoted between 101(18) yr and 330(40) yr, is redetermined by this data to be <span class=\"etd-inline-math\">159.4\\textrm{ yr} \\pm 1.9\\textrm{ yr (statistical)} \\pm 3.7\\textrm{ yr (systematic) with } \\chi<sup>2</sup><sub>DOF</sub> = 1.01</span>. We have also observed a periodic signal in the <span class=\"etd-inline-math\"><sup>32</sup></span>Si/<span class=\"etd-inline-math\"><sup>36</sup></span>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.","abstract_has_math":true,"creators":["Heim, Jordan"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation","degree_discipline":"Physics & Astronomy","degree_department":null,"school":null,"contributors":["Ephraim Fischbach","Andrew Hirsch","Mark Haugan","Fuqiang Wang"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-01-01T08:00:00Z","date_published":"2015-01-01T08:00:00Z","updated_at":"2026-07-24T03:54:44Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://docs.lib.purdue.edu/open_access_dissertations/1415","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Ephraim Fischbach","Andrew Hirsch","Mark Haugan","Fuqiang Wang"]},{"key":"dc:creator","label":"Author","values":["Heim, Jordan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics & Astronomy"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://docs.lib.purdue.edu/open_access_dissertations/1415"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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."]},{"key":"dc:title","label":"Title","values":["The Determination of the Half-Life of Si-32 and Time Varying Nuclear Decay"]}]}],"canonical_facts":{"dc:contributor":["Ephraim Fischbach","Andrew Hirsch","Mark Haugan","Fuqiang Wang"],"dc:creator":["Heim, Jordan"],"dc:description.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."],"dc:identifier":["https://docs.lib.purdue.edu/open_access_dissertations/1415"],"dc:title":["The Determination of the Half-Life of Si-32 and Time Varying Nuclear Decay"],"thesis:degree_discipline":["Physics & Astronomy"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T03:54:44Z"}