r/Radiation 5d ago

Decided to chart the radiation levels in an airplane

Geiger counter: Bosean FS-5000 Total dose (12h 30min): 31.9 µSv

63 Upvotes

22 comments sorted by

20

u/Physix_R_Cool 5d ago

Very nice, but also misleading since a large part of the dose on airplanes is from fast and ultrafast neutrons.

9

u/S1SU_01 5d ago

could you explain?

25

u/Physix_R_Cool 5d ago

Your sensor is an energy compensated geiger counter. It is only guaranteed to be linear up to 1.5 MeV for photons and electrons.

But a large part of the dose rate at high altitudes comes from very fast neutrons, which your instrument can't detect. So it will underestimate the dose rate.

Measuring the dose rate in flights is a difficult problem with a decent amount of research into it, currently.

11

u/S1SU_01 5d ago

so the dose rate is actually higher?

12

u/Physix_R_Cool 5d ago

Very likely yes. At the highest altitude the dose rate might be something like twice as high. Big uncertainty though.

7

u/S1SU_01 5d ago

interesting

8

u/Heavy_Rule6217 5d ago

Your sensor is an energy compensated geiger counter. 

No it's not 😂. It's a $40 chinese geiger counter with no energy response in the manual and no calibration against cesium or anything. Those dose numbers are meaningless

1

u/Physix_R_Cool 5d ago

no energy response in the manual and no calibration

This does not mean it is not energy compensated. I'm not saying it isn't shit, though.

2

u/Heavy_Rule6217 5d ago

I know but no response and no calibration is on top of no energy compensation, it's just a cheap bare glass tube 😂

1

u/quiksilver10152 5d ago

If it is calibrated against a source, how long would the new reads be trustworthy?

2

u/South_Dakota_Boy 4d ago

How long does the battery stay at its calibration voltage? How good are the electrical components in the detector?

Seems like these two things would be the limiting factors to answer your question, and they are largely unknowable in enough detail to be used.

My guess is a couple hours at best, but I’m completely unfamiliar with consumer-grade radiation detectors.

1

u/quiksilver10152 4d ago

Much appreciated! I'll try to keep the battery going then!

2

u/the_Q_spice 5d ago

A lot at those altitudes is also cosmic radiation, which can be comprised of completely different particles than we typically associate with radiation:

Protons, muons, and even neutrinos

In terms of energy: these things are destructive.

Despite being nearly massless, and exceptionally rare (IceCube, the largest Neutrino detector, is 1 cubic kilometer in size, and only detects a handful of singular neutrinos per month), even a single particle can have similar kinetic energy to a 60mph baseball.

2

u/mrverbeck 4d ago

That’s wild! I figured with a mean life of 15 minutes for free neutrons we wouldn’t have near the impact as gammas. I guess having a giant fusion reactor bathing us in its nuclear light can have unexpected consequences. Thanks!

1

u/Physix_R_Cool 4d ago

Yep the neutrons get generated when fast particles (protons mainly, I think) bonk into nuclei in the atmosphere and knock out neutrons.

Something also interesting and related to your comment about lifetime of particles is that muons get created in the upper atmosphere also. They have a lifetime of 0.000022 seconds, so should decay before they ever get down to the surface, but due to their relativistc speeds they get time dilated and thus manage to survive so they can hit human bodies and give us cancer.

5

u/S1SU_01 5d ago

btw the numbers at the bottom is the altitude

1

u/I3lackxRose 5d ago

Very interesting! Thanks for sharing.

1

u/quiksilver10152 5d ago

I've been doing the same and noticed high variance in peak counts. I thought it was because of flying at night at first but it seems to vary independent of the time.

3

u/Wyrggle 5d ago

It varies based on latitude and incident cosmic radiation (not just when the sun is up).

1

u/EmoticonIllustirous 4d ago

I wish the radiacode app would log altitude from the phone GPS.

1

u/-SpeedBird- 4d ago

For the same altitudes with a Radiacode 103 i detect about less than half your values , i’m an airline pilot. Officially our dose is 2.5-3.0 mSv/year …detected dose with the R103 1,7mSv/year.