The part that I keep getting stuck on is chief radiologist Levashov’s report. It’s clear that all of the Ravine 4 were wearing clothing with radioactive contamination well above background, and some of the clothing samples exceeded sanitary guidelines for nuclear workers. But these are hikers, not nuclear workers, so anything significantly above background should raise eyebrows. The Ravine 4 were also the last to be discovered (according to the official records, although they may have been re-discovered if the 1079 theory is correct) and the only ones tested for radiation, at least according to extant records.
If Levashov is truthful and competent, the radiation is beta only. No alpha or gamma detected. This really should raise eyebrows because pure beta emitters are typically manmade isotopes like Sr-90. What would hikers be doing contaminated with Sr-90?
Now there is a caveat here. I remember being very surprised after a Chernobyl trip because a small amount of contamination accidentally found on clothing appeared to be beta only, when I know for a fact that the fission products left in Chernobyl mainly give off a lot of both beta and gamma due to Sr-90 and Cs-137. I later learned that the issue is Geiger counter efficiency. A Geiger counter will register a count for nearly 100% of betas that hit it (assuming they are energetic enough to get through the window), but only a small % of gammas will register a count; most gammas get ignored by the Geiger tube. The amount of contamination was small enough that the beta activity was noticeably above background, but a few percent of the the gamma activity would not register significantly above background. (A more accurate instrument like a NaI(Tl) scintillator has a much higher gamma counting efficiency, but Sverdlovsk probably didn’t have such sophisticated equipment and relied on Geiger counters.)
So it is possible that beta-gamma contamination of the clothing would be recorded as beta-only if the amount was small enough that only the beta could be detected above background. That said, alpha detection is fairly efficient, so any significant amount of alpha contamination (Radium, Thorium, Uranium) can be ruled out.
Lately, I’ve been considering the 1079 theory that the bodies were moved. Could whatever was used to move them before Ivanov’s team re-discovered them have contaminated them? Or could something have happened to them during the move that contaminated them?
Today, I had a new idea. I’m not sure if it is viable, but it can definitely be quantified.
Farmers use chemical fertilizer. Potassium is a common ingredient. For example, potash, which includes potassium compounds such as K2O. Could the bodies have been transported in a truck that carried potash? Also, potash is used for ice melting. Could people have dumped potash on the bodies to speed their thawing during the first investigation before they were brought back to the mountain? (Again, assuming the 1079 theory…)
Let’s try to quantify this. 0.0117% of all potassium is K-40, which is radioactive. K-40 has a 1.251x10^9 year half life. 10.72% of the time it decays by electron capture, emitting a gamma. 89.28% of the time it emits a beta. Yes, it’s not pure beta, but we will examine this later.
The most radioactive clothing was Dubinina’s brown sweater. I also want to double-check Levashov. This measured 640 counts per minute. The background for the instrument was 90 counts per minute. So the sweater was 550 counts per minute. Now there’s an 8.9 correction factor, so the beta activity of the sweater is 4895 cpm. The table lists it as 4900, so we are in agreement and will use that. 4900 cpm / 60 seconds/min = 81.67 Bq (beta decays per second.) If we assume this is all K-40, 81.67 / 0.8928 = 91.5 Bq of K-40 activity.
Now let’s look at electron capture decays producing a gamma. 91.5 Bq * 0.1072 * 0.03 / 8.9 * 60 seconds = 1.2 counts per minute gamma. (I’m making the assumption that the detector is 3% efficient on detecting gammas. I’m also assuming the beta efficiency is 100%, meaning the 8.9 correction factor is all due to detector geometry, and that same geometry applies to gammas.) Considering background is 90 cpm, an additional 1.2 cpm of gamma would likely be considered insignificant. Of note, soil from the site was reported at 96 cpm, so 6 cpm above background, and Levashov did not consider that significant. So I believe K-40 contamination in this amount would be reported by Levashov as beta only.
Next, we need the K-40 specific activity.
SA = (NA * ln 2) / (T1/2 * M) = (6.022E23 * 0.6931) / (1.251E9 * 365 * 24 * 3600 * 40) = 264,500 Bq / g K-40
So we can find the mass of the K-40 that will produce this activity:
91.5 / 264,500 = 346 micrograms K-40
Using the elemental abundance:
346E-6 / 0.000117 = 2.96 g K
Using the molecular weights for K2O:
2.96 g * (39*2+16)/(39*2) = 3.56 g K20
We know Dubinina’s sweater sample was 75 cm^2. So if it was contaminated with 3.6 g potash at the time of discovery, this would exactly explain the radioactivity. That said, that seems like more than one would pick up via trace contamination. I question whether a wheelbarrow that previously held potash would transfer 3.6 g potash to 75 cm^2 of clothing if used to transport the body.
But is it possible that people tried to deice the Ravine 4 bodies with potash or another substance containing potassium, such as potassium chloride? That seems like it might transfer the necessary amounts to their clothing such that if the bodies were then returned to the site and dumped in the ravine, the clothing would still be radioactive.
I’m still a little wary about water solubility, e.g. that the potash or KCl stayed in their clothes and didn’t wash away during the running water in the ravine, as I think they would be water soluble. Also, it must have really got into the clothing, because washing the clothes in the lab in cold water for 3 hours only removed 30-60% of the radioactivity.
Also, it doesn’t explain why anyone on Ivanov’s team would have a Geiger counter and use it to check the bodies for radiation in the first place.
Still, potassium is one simple explanation for the bizarre beta-only results that Levashov observed, which doesn’t require a purified manmade isotope like Sr-90.