[ RadSafe ] variability of decay constants

[HOWARD.LONG at comcast.net]

"Variation of Constant" 

Wow! Is nuclear decay, like human decay, 

inevitable but somewhat unpredictable? 



Is nuclear physics, like physician observation, 

art as well as science?  Humbling! 



Howard Long 



----- Original Message ----- 
From: "George Stanford" <gstanford at aya.yale.edu> 
To: "Peter Bossew" <Peter.Bossew at reflex.at> 
Cc: radsafe at radlab.nl 
Sent: Sunday, July 26, 2009 12:24:50 PM GMT -08:00 US/Canada Pacific 
Subject: Re: [ RadSafe ] variability of decay constants 

Peter: 

      Thanks -- interesting. 

      Paper #1 seems ill-founded.  Since seasonal 
temperatures have a phase delay of about a month, 
it only take a glance at the charts in that paper 
to see that the correlation with seasonal 
temperature would be much better than with earth-sun distance. 

      Paper #2 shows how the temperature changes 
can affect the measurements and account for the 
observations  Small seasonal changes in the 
temperature in the laboratory can cause changes in: 
-  argon density in an ionization chamber, affecting counter sensitivity; 
-  air density between radioactive source and 
detector, affecting beta-ray transmission. 

      When you're trying to measure effects as 
small as +/- 0.15%, you've got to be pretty darn 
careful with your experimental conditions. 

      It looks as though decay probabilities remain immutable. 

      -- George 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

At 02:20 PM 7/25/2009, Peter Bossew wrote: 
For those interested in more fundamental questions: 2 articles on the 
alleged temporal variability of decay constants. 

1) 
Evidence for Correlations Between Nuclear Decay Rates and Earth-Sun 
Distance 
Jere H. Jenkins et al., 
http://arxiv.org/abs/0808.3283v1 

Abstract 
Unexplained periodic fluctuations in the decay rates of Si-32 and Ra-226 
have been reported by groups at Brookhaven National Laboratory (Si-32), 
and at the Physikalisch-Technische-Bundesandstalt in Germany (Ra-226). We 
show from an analysis of the raw data in these experiments that the 
observed fluctuations are strongly correlated in time, not only with each 
other, but also with the distance between the Earth and the Sun. Some 
implications of these results are also discussed, including the suggestion 
that discrepancies in published half-life determinations for these and 
other nuclides may be attributable in part to differences in solar 
activity during the course of the various experiments, or to seasonal 
variations in fundamental constants. 


2) 
Oscillations in radioactive exponential decay 
T.M. Semkov et al. 
Physics Letters B 675,5 (2009) 415­419 
doi:10.1016/j.physletb.2009.04.051 

Abstract 
Several older and recent reports provided evidence for the oscillatory 
character of the exponential decay law in radioactive decay and attempted 
to explain it with basic physics. We show here that the measured effects 
observed in some of the cases, namely in the decay of 226Ra, 32Si in 
equilibrium, and 36Cl, can be explained with the temperature variations. 

(more lit. there) 


Peter 

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