Perturbation of nuclear decay rates during the solar flare of 2006 December 13
TL;DR: In this paper, the decay rate of 54 Mn was detected during the solar flare of 2006 December 13, whose X-rays were first recorded at 02:37 UT (21:37 EST on 2006 December 12).
About: This article is published in Astroparticle Physics.The article was published on 2009-07-01 and is currently open access. It has received 99 citations till now. The article focuses on the topics: Radioactive decay & Solar flare.
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TL;DR: The question of whether nuclear decay rates (or half-lives) are time-independent constants of nature, as opposed to being parameters which can be altered by an external perturbation has been discussed in this paper.
Abstract: This paper presents an overview of recent research dealing with the question of whether nuclear decay rates (or half-lives) are time-independent constants of nature, as opposed to being parameters which can be altered by an external perturbation. If the latter is the case, this may imply the existence of some new interaction(s) which would be responsible for any observed time variation. Interest in this question has been renewed recently by evidence for a correlation between nuclear decay rates and Earth–Sun distance, and by the observation of a dip in the decay rate for 54Mn coincident in time with the solar flare of 2006 December 13. We discuss these observations in detail, along with other hints in the literature for time-varying decay parameters, in the framework of a general phenomenology that we develop. One consequence of this phenomenology is that it is possible for different experimental groups to infer discrepant (yet technically correct) results for a half-life depending on where and how their data were taken and analyzed. A considerable amount of attention is devoted to possible mechanisms which might give rise to the reported effects, including fluctuations in the flux of solar neutrinos, and possible variations in the magnitudes of fundamental parameters, such as the fine structure constant and the electron-to-proton mass ratio. We also discuss ongoing and future experiments, along with some implications of our work for cancer treatments, 14C dating, and for the possibility of detecting the relic neutrino background.
102 citations
11 Aug 2010-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a detailed analysis of the responses of the detectors actually used in the BNL and PTB experiments, and show that sensitivities to seasonal variations in the respective detectors are likely too small to produce the observed fluctuations.
Abstract: In a recent series of papers evidence has been presented for correlations between solar activity and nuclear decay rates. This includes an apparent correlation between Earth–Sun distance and data taken at Brookhaven National Laboratory (BNL), and at the Physikalisch-Technische Bundesanstalt (PTB). Although these correlations could arise from a direct interaction between the decaying nuclei and some particles or fields emanating from the Sun, they could also represent an “environmental” effect arising from a seasonal variation of the sensitivities of the BNL and PTB detectors due to changes in temperature, relative humidity, background radiation, etc. In this paper, we present a detailed analysis of the responses of the detectors actually used in the BNL and PTB experiments, and show that sensitivities to seasonal variations in the respective detectors are likely too small to produce the observed fluctuations.
63 citations
TL;DR: In this article, a spectral analysis of nuclear decay data displaying annually varying periodic fluctuations is presented. But, the spectral properties of the decay data were not analyzed and no common phases were found between the factors investigated and those exhibited by the nuclear decay.
51 citations
TL;DR: In this paper, the authors presented experimental evidence in support of the recent hypothesis that a possible solar influence could explain fluctuations observed in the measured decay rates of some isotopes during routine weekly calibrations of an instrument used for radiological safety at The Ohio State University Research Reactor using 36 Cl.
48 citations
TL;DR: In this paper, the activity of a 137C source has been measured by means of a HPGe detector installed deep underground in the Gran Sasso Laboratory, which allowed the search for time variations of the decay constant with periods from a few hours to 1 year.
47 citations
References
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TL;DR: In this paper, the decay rates of 32 Si and 226 Ra have been investigated at Brookhaven National Laboratory (32 Si) and at the Physikalisch-Technische-Bundesanstalt in Germany (226 Ra).
185 citations
TL;DR: In this article, the authors reexamined their previously published data to search for evidence of correlations between the rates for the alpha, beta-minus, beta plus, and electron capture decays of 22Na, 44Ti, 108Agm, 121Snm, 133Ba, and 241Am and the Earth?Sun distance.
85 citations
TL;DR: In this paper, the power output of the radioisotope thermoelectric generators aboard the Cassini spacecraft was used to test the conjecture that small deviations observed in terrestrial measurements of the exponential radioactive decay law are correlated with the Earth-Sun distance.
81 citations
TL;DR: In this paper, the authors estimate the magnitude of the signals expected for realistic cosmic neutrino background in detectors attempting to measure the mechanical forces exerted on macroscopic targets by the elastic scattering of relic neutrinos.
Abstract: Here we estimate the magnitude of the signals expected for realistic cosmic neutrino backgrounds in detectors attempting to measure the mechanical forces exerted on macroscopic targets by the elastic scattering of relic neutrinos. We study effects proportional to the weak coupling constant ${G}_{F}$ and to ${G}_{F}^{2}$ for Dirac and Majorana neutrinos, either relativistic or nonrelativistic, both gravitationally bound or not.
61 citations
TL;DR: In this paper, a broad-beam 238Pu/Be neutron irradiator has been previously developed for exclusive use in in vivo neutron activation analysis in humans and the initial calibrations of the facility provided only a fixed value for the thermal neutron flux.
Abstract: A broad-beam 238Pu/Be neutron irradiator has been previously developed for exclusive use in in vivo neutron activation analysis in humans. The initial calibrations of the facility provided only a fixed value for the thermal neutron flux. Adjustment of this flux value for decay of the neutron source was later introduced and was based on the physical half-life of 238Pu. The current findings would suggest, however, that a more appropriate value for the effective half-life for the total body irradiator is 141.7+or-2.5 y. In addition, variations in the induced counts for a Mn standard on a yearly basis indicate that seasonal differences of approximately 0.5% can be present between the winter and summer months.
38 citations