Hypothesis
My intuition tells me that high electrostatic potential must increase the rate of natural radioactive decay. I hypothesize that high positive electrostatic potential accelerates clocks at nuclear level. To test this hypothesis I decided to take relatively unstable (i.e. relatively short-lived) isotopes of 109Cd (half-life of 461 days) and 65Zn (half-life of 244 days), place them on a positive-polarity van der Graaf generator – Fig. 1, charge the generator to max potential (1.6 megavolt in my case), and measure the sample activity before and after the exposure.
If the exposure to the high positive electrostatic potential indeed accelerates nuclear time I should detect a reduction in sample activity after the exposure.
Zn-65
The activity of my samples (which I procured from Spectrum Techniques) was 0.1 uCi each. I have measured the 65Zn activity using the 2″ Bicron NaI(Tl) detector coupled to the Scinonix VD-14HV base connected to the PicoScope 4262 running the PulseCounter software – Fig. 2.
I did not detect any reduction in gamma activity after running 3 separate experiments where I exposed the sample to the positive-polarity VDG for 1 hour each time. The sample activity remained at ~556 CPS as measured by my setup – Fig. 3.
Cd-109
To measure 109Cd activity I used a CapeSym SC-14x25c SrI2 detector coupled to the same PicoScope 4262 running the PulseCounter software – Fig. 4.
I did not detect any reduction in gamma activity after running 3 separate experiments where I exposed the sample to the positive-polarity VDG for 1 hour each time. The sample activity remained at ~830 CPS as measured by my setup – Fig. 5.
Never mind that the the software reports the change of activity as ‘significant’. The change is due to a systematic error resulting from the imprecise sample position with respect to the detector. This and other sources of systematic errors I have addressed in my previous blog post. The SrI2 detector temperature also changed between the runs, which resulted in slight shift of the 22 keV peak, which nevertheless did not affect the total counts. The bottom line is – there is no obvious change in activity after 3 separate exposures to the positive polarity VDG. The observed minor changes are random (i.e. both bigger and smaller than the baseline corresponding to the activity of the ‘virgin’ sample) and most definitely result from imprecise sample positioning.
Conclusion
Although I was not able to show the reduction in sample activity due to positive-polarity VDG exposure I did not yet disprove the hypothesis. The obvious flaw of the experiment was poor quality of the VDG generator, which I purchased from Physics Playground. This generator is a toy that is not meant to run for hours on end. Plastic parts and rubber pulleys fail constantly. Also, the generator must be fitted with an electrostatic field meter to monitor the electrostatic potential. I do not know if the generator actually achieved the 1.6 megavolt potential claimed in the specification. Or perhaps larger potential is necessary to see the effect.
However, the results obtained so far do not support the hypothesis.
PS Placing the samples inside the VDG sphere did not produce a measurable reduction in counts. Therefore, I detected no reduction of activity regardless of the sample placement on top or inside the VDG sphere.
PPS Switching the VDG polarity from positive to negative did not make a difference. Although the electrostatic charge was greater when using the negative polarity.
PPPS Po-210 decay rate is not affected by the negative multi-hour polarity VDG exposure.