To test a hypothesis that high electrostatic potential may affect the rate of natural radioactive decay I have taped three samples Cd-109, Zn-65, and Po-210 (0.1 uCi each) to the top load of a high-voltage Tesla coil energized to a very high potential – Fig. 1.

The samples were exposed to few million volts of the coil’s potential for an hour, measured, then exposed for another hour to a somewhat higher potential (harder coil drive), them measured again. Gamma activity was measured before the exposure and after using the setup shown on Fig. 2.

To measure gamma spectrum I used a Bicron 2×2 NaI(Tl) probe coupled to a Scionix self-biased PMT base connected to a PicoScope 4262 running PulseCounter software.

Cd-109 activity diminished very little after the exposure – Fig. 3.

Although the change in activity is deemed statistically significant (P<0.000), the reduction is only 1% and can possibly be caused by an unknown systematic error (like sample placement inaccuracy).

There was no change in Zn-65 activity at all – Fig. 4.

Po-210 activity was measured using the setup shown on Fig. 5.

The alpha-counting setup consisted of the MCA-LITE connected to the Eberline AC-3 alpha probe. Po-210 alpha counts appear to have reduced significantly, down 20% compared to the original sample – Fig. 6.

These results are encouraging although it is difficult to rule-out sample migration due to electrostatic forces since the Po-210 sample is not embedded in plastic but rather is deposited on a film inside the plastic sample holder. Because it takes a very small amount of material to produce a 0.1 uCi Po-210 source such sample migration cannot be ruled out and may be responsible for the observed reduction in alpha activity.

Conclusion

Exposure to high voltage Tesla coil does not seem to affect gamma activity of Zn-65 or Cd-109. However, there was a significant (20%) reduction in Po-210 activity. However, the reduction of the Po-210 activity was not cumulative: the second exposure dud not further reduce the counts, therefore the reduction is most likely caused by the sample migration.