oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Additional experimental evidence for a solar influence on nuclear decay rates  [PDF]
Jere H. Jenkins,Kevin R. Herminghuysen,Thomas E. Blue,Ephraim Fischbach,Daniel Javorsek II,Andrew C. Kauffman,Daniel W. Mundy,Peter A. Sturrock,Joseph W. Talnagi
Physics , 2012, DOI: 10.1016/j.astropartphys.2012.07.008
Abstract: Additional experimental evidence is presented in support of the recent hypothesis that a possible solar influence could explain fluctuations observed in the measured decay rates of some isotopes. These data were obtained during routine weekly calibrations of an instrument used for radiological safety at The Ohio State University Research Reactor using Cl-36. The detector system used was based on a Geiger-Mueller gas detector, which is a robust detector system with very low susceptibility to environmental changes. A clear annual variation is evident in the data, with a maximum relative count rate observed in January/February, and a minimum relative count rate observed in July/August, for seven successive years from July 2005 to June 2011. This annual variation is not likely to have arisen from changes in the detector surroundings, as we show here.
Evidence for Solar Influences on Nuclear Decay Rates  [PDF]
Ephraim Fischbach,Peter A. Sturrock,Jere H. Jenkins,Daniel Javorsek II,John B. Buncher,John T. Gruenwald
Physics , 2010,
Abstract: Recent reports of periodic fluctuations in nuclear decay data of certain isotopes have led to the suggestion that nuclear decay rates are being influenced by the Sun, perhaps via neutrinos. Here we present evidence for the existence of an additional periodicity that appears to be related to the Rieger periodicity well known in solar physics.
Solar Influence on Nuclear Decay Rates: Constraints from the MESSENGER Mission  [PDF]
Ephraim Fischbach,K. Joseph Chen,Robert E. Gold,John O. Goldsten,David J. Lawrence,Ralph J. McNutt Jr.,Edgar A. Rhodes,Jere H. Jenkins,James M. Longuski
Physics , 2011, DOI: 10.1007/s10509-011-0808-5
Abstract: We have analyzed Cs-137 decay data, obtained from a small sample onboard the MESSENGER spacecraft en route to Mercury, with the aim of setting limits on a possible correlation between nuclear decay rates and solar activity. Such a correlation has been suggested recently on the basis of data from Mn-54 decay during the solar flare of 13 December 2006, and by indications of an annual and other periodic variations in the decay rates of Si-32, Cl-36, and Ra-226. Data from five measurements of the Cs-137 count rate over a period of approximately 5.4 years have been fit to a formula which accounts for the usual exponential decrease in count rate over time, along with the addition of a theoretical solar contribution varying with MESSENGER-Sun separation. The indication of solar influence is then characterized by a non-zero value of the calculated parameter \xi, and we find \xi=(2.8+/-8.1)x10^{-3} for Cs-137. A simulation of the increased data that can hypothetically be expected following Mercury orbit insertion on 18 March 2011 suggests that the anticipated improvement in the determination of \xi could reveal a non-zero value of \xi if present at a level consistent with other data.
Further Evidence Suggestive of a Solar Influence on Nuclear Decay Rates  [PDF]
Peter A. Sturrock,Ephraim Fischbach,Jere H. Jenkins
Physics , 2011, DOI: 10.1007/s11207-011-9807-5
Abstract: Recent analyses of nuclear decay data show evidence of variations suggestive of a solar influence. Analyses of datasets acquired at the Brookhaven National Laboratory (BNL) and at the Physikalisch-Technische Bundesanstalt (PTB) both show evidence of an annual periodicity and of periodicities with sidereal frequencies in the neighborhood of 12.25 year^{-1} (at a significance level that we have estimated to be 10^{-17}). It is notable that this implied rotation rate is lower than that attributed to the solar radiative zone, suggestive of a slowly rotating solar core. This leads us to hypothesize that there may be an "inner tachocline" separating the core from the radiative zone, analogous to the "outer tachocline" that separates the radiative zone from the convection zone. The Rieger periodicity (which has a period of about 154 days, corresponding to a frequency of 2.37 year^{-1}) may be attributed to an r-mode oscillation with spherical-harmonic indices l=3, m=1, located in the outer tachocline. This suggests that we may test the hypothesis of a solar influence on nuclear decay rates by searching BNL and PTB data for evidence of a "Rieger-like" r-mode oscillation, with l=3, m=1, in the inner tachocline. The appropriate search band for such an oscillation is estimated to be 2.00-2.28 year^{-1}. We find, in both datasets, strong evidence of a periodicity at 2.11 year^{-1}. We estimate that the probability of obtaining these results by chance is 10^{-12}.
The Case for a Solar Influence on Certain Nuclear Decay Rates
Sturrock, Peter;Fischbach, Ephraim;Javorsek II, Daniel;Jenkins, Jere;Lee, Robert
High Energy Physics - Phenomenology , 2013,
Abstract: Power-spectrum analyses of the decay rates of certain nuclides reveal (at very high confidence levels) an annual oscillation and periodicities that may be attributed to solar rotation and to solar r-mode oscillations. A comparison of spectrograms (time-frequency displays) formed from decay data and from solar neutrino data reveals a common periodicity with frequency 12.5 year-1, which is indicative of the solar radiative zone. We propose that the neutrino flux is modulated by the solar magnetic field (via Resonant Spin Flavor Precession) in that region, and we estimate the force and the torque that could be exerted on a nuclide by the solar neutrino flux.
The Case for a Solar Influence on Certain Nuclear Decay Rates  [PDF]
Peter Sturrock,Ephraim Fischbach,Daniel Javorsek II,Jere Jenkins,Robert Lee
Physics , 2013,
Abstract: Power-spectrum analyses of the decay rates of certain nuclides reveal (at very high confidence levels) an annual oscillation and periodicities that may be attributed to solar rotation and to solar r-mode oscillations. A comparison of spectrograms (time-frequency displays) formed from decay data and from solar neutrino data reveals a common periodicity with frequency 12.5 year-1, which is indicative of the solar radiative zone. We propose that the neutrino flux is modulated by the solar magnetic field (via Resonant Spin Flavor Precession) in that region, and we estimate the force and the torque that could be exerted on a nuclide by the solar neutrino flux.
Alpha-decay Rates of Yb and Gd in Solar Neutrino Detectors  [PDF]
M. Fujiwara,T. Kawabata,P. Mohr
Physics , 2002, DOI: 10.1088/0954-3899/28/4/305
Abstract: The $\alpha$-decay rates for the nuclides $^{168,170,171,172,173,174,176}$Yb and $^{148,150,152,154}$Gd have been estimated from transmission probabilities in a systematic $\alpha$-nucleus potential and from an improved fit to $\alpha$-decay rates in the rare-earth mass region. Whereas ${\alpha}$-decay of $^{152}$Gd in natural gadolinium is a severe obstacle for the use of gadolinium as a low-energy solar-neutrino detector, we show that ${\alpha}$-decay does not contribute significantly to the background in a ytterbium detector. An extremely long ${\alpha}$-decay lifetime of $^{168}$Yb is obtained from calculation, which may be close to the sensitivity limit in a low-background solar neutrino detector.
Rising and Decay Rates of Solar Quiet Daily Variation and Electrojet at Equatorial Region
A.B. Rabiu,Nandini Nagarajan,K. Saratchandra
Online Journal of Earth Sciences , 2012,
Abstract: The rates of rising and decay of solar quiet daily variation, Sq and equatorial electrojet, EEJ, strength at equatorial zone have been quantified and examined over a long term (1980-2000). A quantitative measurement of the rising and decay rates are proposed and used in the study. Estimated rates and their ratios are subjected to morphological and statistical analysis. The rising and decay rates exhibit day-to-day variability and traditional geomagnetic equinoctial maximum. The daily rates are solar controlled with Sq showing greater response to solar activity than EEJ. The rising rate is greater than decay rate for both current systems. Electromagnetic induction effect is expected to be greater during the rising of the currents. While EEJ builds faster than Sq, they both exhibit insignificant different decay rates. The cumulative mean values of (rising; decay) rates for the entire period are (10.49; 7.02) nT h-1 and (8.54; 7.09) nT h-1 for EEJ strength and Sq, respectively. The diurnal rates demonstrate positive correlation with the ionospheric and existing Sq current /EEJ model parameters. The ratio of the rising rate to decay rate has an average value of 1.57±0.51nT h-1 for EEJ and 1.22±0.26 nT h-1 for WSq. The results indicate that the effect of local wind activity on the ionospheric dynamo process is more pronounced in the EEJ field than Sq.
An Analysis of Apparent r-Mode Oscillations in Solar Activity, the Solar Diameter, the Solar Neutrino Flux, and Nuclear Decay Rates, with Implications Concerning the Solar Internal Structure and Rotation, and Neutrino Processes  [PDF]
P. A. Sturrock,L. Bertello,E. Fischbach,D. Javorsek II,J. H. Jenkins,A. Kosovichev,A. G. Parkhomov
Physics , 2012, DOI: 10.1016/j.astropartphys.2012.11.011
Abstract: This article presents a comparative analysis of solar activity data, Mt Wilson diameter data, Super-Kamiokande solar neutrino data, and nuclear decay data acquired at the Lomonosov Moscow State University (LMSU). We propose that salient periodicities in all of these datasets may be attributed to r-mode oscillations. Periodicities in the solar activity data and in Super-Kamiokande solar neutrino data may be attributed to r-mode oscillations in the known tachocline, with normalized radius in the range 0.66 to 0.74, where the sidereal rotation rate is in the range 13.7 to 14.6 year-1. We propose that periodicities in the Mt Wilson and LMSU data may be attributed to similar r-mode oscillations where the sidereal rotation rate is approximately which we attribute to a hypothetical inner tachocline separating a slowly rotating core from the radiative zone. We also discuss the possible role of the RSFP (Resonant Spin Flavor Precession) process, which leads to estimates of the neutrino magnetic moment and of the magnetic field strength in or near the solar core.
Disproof of solar influence on the decay rates of 90Sr/90Y  [PDF]
Karsten Kossert,Ole N?hle
Physics , 2014, DOI: 10.1016/j.astropartphys.2015.03.003
Abstract: A custom-built liquid scintillation counter was used for long-term measurements of 90Sr/90Y sources. The detector system is equipped with an automated sample changer and three photomultiplier tubes, which makes the application of the triple-to-double coincidence ratio (TDCR) method possible. After decay correction, the measured decay rates were found to be stable and no annual oscillation could be observed. Thus, the findings of this work are in strong contradiction to those of Parkhomov [1] who reported on annual oscillations when measuring 90Sr/90Y with a Geiger-M\"uller counter. Sturrock et al. [2] carried out a more detailed analysis of the experimental data from Parkhomov and claimed to have found correlations between the decay rates and processes inside the Sun. These findings are questionable, since they are based on inappropriate experimental data as is demonstrated in this work. A frequency analysis of our activity data does not show any significant periodicity.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.