Radiation and Local Interest, Learning, Anticlimax

I received a Geiger counter over the holiday. After reading some reviews, it seemed prudent to open it up and see what I had. I was happy to see that it uses a decent Geiger Muller tube, though an upgrade looked to be cheap and easy. Disappointingly, this unit does not click when a particle is detected, but I may get around to adding that feature someday.

Not far from where I live, and up-wind as it turns out, is the former site of a Rockwell munitions plant, which had some fires and fallout in the 50s and 60s, as well as serious violations of storage regulation, leading to more plutonium than a neighborhood would like to hear about getting blown across the landscape.

A couple of decades ago, this site was cleaned up and ultimately became a wildlife refuge. Over the weekend I decided to go for a walk, and take my device with me. I’d been measuring an average of 0.12uSv/h at my desk, and actually found the same or lower levels while walking the park. As this is where I live, I was glad to see no noticeable difference.

With my limited understanding, I read this a couple of ways.

  1. It’s likely that the cleanup effort was successful, as NGOs in my area take these things very seriously, even if the private industry that made the mess in the first place did not.
  2. The material, and the source of the fires, was plutonium. Plutonium, IIRC, emits primarily alpha particles, which are relatively easy to contain. It is entirely possible that disturbed soil could shake out more particles, or that the case of my device is capable of blocking alpha particles.
  3. I have no way to verify my device, so I really just have to trust it as it is. Perhaps as I learn more I can perform some experiments to help me better understand the limitations of this cheap, consumer device.

In any case, this has already been a fun device to own, and opens doors to further learning on my part, which I greatly enjoy.


Having written this, there are more thoughts banging around in my head:

  • How can I dump the firmware on the device?
  • If I understand correctly, the MCU is an clone of the STM “blue pill” processor
  • There are 4 interface pads just north of the MCU on the board, how can those be utilized?
  • Is there a possibility of adding features to this kind of device by dumping and forking the firmware?

RE: point 2, did you take the device out to the site with the case open or off to see if there was any change in measured particles? Might be a way to answer the question of whether the case itself is capable of blocking any types of radiation thereby giving an incorrect reading.

Just a thought.

And yeah, what kind of Geiger counter doesn’t click or beep while measuring particles??? Definite design fail I think, unless it’s supposed to be something that you take in to some plant surreptitiously before blowing the whistle on radiological violations. :slight_smile:

Learning more about alpha particles, they not only are easily blocked, but travel only centimeters. Should I decide to shift focus to them, it might mean different conditions, different equipment.

There is a small hack to add a capacitor and wire from the LED driver - it does blink an LED on detection - to the piezo transducer. When I feel like this kind of task, I’m very likely to do that. That is, if I don’t dump and modify the firmware.

1 Like

This is really interesting, having one for personal use.

We have a nuclear waste facility very close by, it’s actually where a number of the local hiking and mountain bike trails are now. It’s also next to a waste dump and they have underground trash fires in the summers and I’ve always been curious how contained everything is there.

1 Like

Now I also want to have a Geiger counter, even though I have no knowledge about the subject matter. On the village I grew up in, my grandma told me back then that they weren’t allowed to eat vegetables after the radioactive cloud from Chernobyl passed over Germany :confused:

1 Like

I’ve had one on my back-burner want list for many years. I should have bought the old but basically brand new Civil Defense one I saw in a consignment shop back in the nineties. If only I hadn’t been broke at the time. :expressionless: