Good work Bob.
Eliminating a possible radon signal will make a stronger case from gammas when the experiment is replicated. Russ’s suggestion is wise… the Aware device is also worth buying as it is simple, responsive and permits data-logging of radiation in another way which will overlap with the NaI. From: Russ George Interesting work. One simple thing to perhaps try is to set up a ‘radon flea’ trap at the lab, capture some ‘fleas’ and examine their spectra with the instrument. This comparison would settle this question one way or the other pretty quick and easy. The fellow who runs Aware Electronics and make Geigers has pages and pages of info on catching and examining radon fleas. http://www.aw-el.com Russ From: Bob Higgins Based on comments from Jones and others, I have done some analysis to determine if the GS5.2 signal in Spectrum-07 could have come from gamma produced from radon gas decay progeny. First, Alan Goldwater produced a map showing the areas where radon levels were high in his area. In the area of his lab, radon levels are low, but they are higher where Jeff Morris did his work. Internet participant, Ecco, found a plot of gamma emissions from radon progeny - I put it here: https://drive.google.com/open?id=0B5Pc25a4cOM2cnV6U0V5Z3MxSXM I took this graph, digitized it, calibrated the energy scale, and resampled it to the same energy scale and samples as the GS5.2 Spectrum-07 calibrated signal data. Then I hypothesized, what if the Spectrum-07 signal came from radon? So, I normalized the radon progeny spectrum to have the same total counts as the Spectrum-07 signal and overlaid the two on the same graph. You can find the high resolution graph here: https://drive.google.com/open?id=0B5Pc25a4cOM2Yk8xQlNZOHo3ZVk I am going to try to include a small version of the graph in this email, but I am not it will be passed on: What can be seen in the overlay is that the two spectra are clearly different. If the GS5.2 Spectrum-07 signal were due to radon progeny gamma, a distinct peak would have been seen at 610 keV, and by contrast, the GS5.2 Spectrum-07 signal is clearly smooth.
