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Is this text relevant?

  1. Jul 24, 2011 #1
  2. jcsd
  3. Jul 24, 2011 #2

    Vanadium 50

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    Relevant to what?

    This is a result that no independent group has been able to confirm.
     
  4. Jul 24, 2011 #3

    Drakkith

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    I don't believe the effect has been reproduced by anyone. If not, then no, it is not really relevant.
     
  5. Jul 24, 2011 #4

    bcrowell

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    FAQ: Do rates of nuclear decay depend on environmental factors?

    There is one environmental effect that has been scientifically well established for a long time. In the process of electron capture, a proton in the nucleus combines with an inner-shell electron to produce a neutron and a neutrino. This effect does depend on the electronic environment, and in particular, the process cannot happen if the atom is completely ionized.

    Other claims of environmental effects on decay rates are crank science, often quoted by creationists in their attempts to discredit evolutionary and geological time scales.

    He et al. (He 2007) claim to have detected a change in rates of beta decay of as much as 11% when samples are rotated in a centrifuge, and say that the effect varies asymmetrically with clockwise and counterclockwise rotation. He believes that there is a mysterious energy field that has both biological and nuclear effects, and that it relates to circadian rhythms. The nuclear effects were not observed when the experimental conditions were reproduced by Ding et al.

    Jenkins and Fischbach (2008) claim to have observed effects on alpha decay rates at the 10^-3 level, correlated with an influence from the sun. They proposed that their results could be tested more dramatically by looking for changes in the rate of alpha decay in radioisotope thermoelectric generators aboard space probes. Such an effect turned out not to exist (Cooper 2009). Undeterred by their theory's failure to pass their own proposed test, they have gone on to publish even kookier ideas, such as a neutrino-mediated effect from solar flares, even though solar flares are a surface phenomenon, whereas neutrinos come from the sun's core. An independent study found no such link between flares and decay rates (Parkhomov 2010a). Laboratory experiments[Lindstrom 2010] have also placed limits on the sensitivity of radioactive decay to neutrino flux that rule out a neutrino-mediated effect at a level orders of magnitude less than what would be required in order to explain the variations claimed in [Jenkins 2008].

    Jenkins and Fischbach's latest claims, in 2010, are based on experiments done decades ago by other people, so that Jenkins and Fischbach have no first-hand way of investigating possible sources of systematic error. Other attempts to reproduce the result are also plagued by systematic errors of the same size as the claimed effect. For example, an experiment by Parkhomov (2010b) shows a Fourier power spectrum in which a dozen other peaks are nearly as prominent as the claimed yearly variation.

    Cardone et al. claim to have observed variations in the rate of alpha decay of thorium induced by 20 kHz ultrasound, and claim that this alpha decay occurs without the emission of gamma rays. Ericsson et al. have pointed out multiple severe problems with Cardone's experiments.

    He YuJian et al., Science China 50 (2007) 170.

    YouQian Ding et al., Science China 52 (2009) 690.

    Jenkins and Fischbach (2008), http://arxiv.org/abs/0808.3283v1, Astropart.Phys.32:42-46,2009

    Jenkins and Fischbach (2009), http://arxiv.org/abs/0808.3156, Astropart.Phys.31:407-411,2009

    Jenkins and Fischbach (2010), http://arxiv.org/abs/1007.3318

    Parkhomov 2010a, http://arxiv.org/abs/1006.2295

    Parkhomov 2010b, http://arxiv.org/abs/1012.4174

    Cooper (2009), http://arxiv.org/abs/0809.4248, Astropart.Phys.31:267-269,2009

    Lindstrom et al. (2010), http://arxiv.org/abs/1006.5071, Nuclear Instruments and Methods in Physics Research A, 622 (2010) 93-96

    F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956

    Ericsson et al., Comment on "Piezonuclear decay of thorium," Phys. Lett. A 373 (2009) 1956, http://arxiv4.library.cornell.edu/abs/0907.0623 [Broken]

    Ericsson et al., http://arxiv.org/abs/0909.2141
     
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