CJ
Member
Yesterday I decided to have a play with my radiation detector in a Peak District cave/mine as I was curious to compare the background levels of radiation compared to the surface. First of all, it's worth pointing out that this device does NOT use a Geiger-Müller tube, it's a scintillation counter..
For anyone who doesn't know; scintillation counters are far superior when it comes to radiation sensitivity and detecting lower levels of radiation. The other advantage is that they're much tougher and doesn't rely on a fragile glass tube. All in all, they're pretty cool bits of tech... However, they're only really good for detecting X-ray/gamma and beta radiation. This means that I'm only detecting the beta and gamma radiation associated with the decay of radon daughters. I have not done a literature review, so I'm sure there's already an abundance of studies into the comparative background radiation found underground, but reading them is less fun.
^^
As you can see, above the shaft I'm getting an average count per min of 36, and an average reading of 0.06µSv per hour.
^^
Below ground I'm getting an average CPM of 99 and twice the average µSv/h
In summary: for every hour spent underground, I was exposed to around 0.12µSv/h!! DOUBLE what I would be exposed to above ground.
To put this into perspective, that's the same as A CHEST X-RAY! Just kidding... It's actually the same as 1x 150g banana per hour (albeit cumulative).
Those numbers do add up over time, especially when each digging session can easily be 6-8h+
But I'd wager that the exposure to alpha particles are more "concerning" (comparatively speaking)?
For more info on radiation dosing and comparisons: Radiation Exposure Chart
For anyone who doesn't know; scintillation counters are far superior when it comes to radiation sensitivity and detecting lower levels of radiation. The other advantage is that they're much tougher and doesn't rely on a fragile glass tube. All in all, they're pretty cool bits of tech... However, they're only really good for detecting X-ray/gamma and beta radiation. This means that I'm only detecting the beta and gamma radiation associated with the decay of radon daughters. I have not done a literature review, so I'm sure there's already an abundance of studies into the comparative background radiation found underground, but reading them is less fun.
^^
As you can see, above the shaft I'm getting an average count per min of 36, and an average reading of 0.06µSv per hour.
^^
Below ground I'm getting an average CPM of 99 and twice the average µSv/h
In summary: for every hour spent underground, I was exposed to around 0.12µSv/h!! DOUBLE what I would be exposed to above ground.
To put this into perspective, that's the same as A CHEST X-RAY! Just kidding... It's actually the same as 1x 150g banana per hour (albeit cumulative).
Those numbers do add up over time, especially when each digging session can easily be 6-8h+
But I'd wager that the exposure to alpha particles are more "concerning" (comparatively speaking)?
For more info on radiation dosing and comparisons: Radiation Exposure Chart