Cosmic Radiation?

[DUAL RATED]

Im curious to find out what equipment is being used out there to monitor Cosmic radiation, actual detection or just calculations based on average exposure etc in a computer program

[Jeff Claims]

Try here for clues:
http://domino.lancs.ac.uk/INFO/LUNews.nsf/Tx/45C1D2A79459617580256E1B003510E9 (http://)

J.

[fear_not]

A simple dosimeter would to the trick. I actually wonder why no pilot (+flightcrew) is required to use the dosimeter.
By us at the university, we are required to use one when ever their is a slight chance for a periodical exposur to any form of harmfull radiation.
http://en.wikipedia.org/wiki/Dosimeter

[idg]

F_N,

I don't believe that a 'normal' dosimeter will do the trick because it's designed to read the wrong sort of exposure.

We assumed this when conducting a trial a long time ago in HKG. The control badges that were left in the desk of the association headquarters registered more radiation than those carried by many of our crews for several months!

The reason we assumed when checking later was that since HKG is built on granite, which has a much higher normal rediation level than 'terra firma', the control badges were being 'contaminated' with this radiation.

Memory is a bit hazy as to which radiation is which but you definitely have to get the right kit to measure it.

[fear_not]

@idg

theire are 3 kinds of radiation:

1. aplha rays (high speed helium nucleus)
zero danger outside the body (the skin stops the alpha ray)
high danger if the radioactive substance emiting it is inside the body

2. beta rays (high speed electrons)
low danger outside the body (penetrates the skin by a few milimeters)
medium danger inside the body

3. gamma rays (high energy EM)
high danger outside the body (goes through the whole body)
low danger inside the body

You are right does dosimeter work on the basis that ionisation occures as the rays go through the detector.
Alpha and beta rays are strong ionising rays while gamma rays dont realy ionise that strongly. So a dosimeter will have difficulties recording gamma rays.

That building where you headquaters seems to have a high contamination of radon (I believe they radiate alpha rays, but i am not sure would have to look that one up) gas produced by the decay of uranium inside of granit.
I dont know how much the dosimeter measured on the ground but one shouldnt underestimate the risk caused by radon. Maybe they should get better ventilation at the headquater to reduce the level of radon.

Comming back to how to measure the radiation on the plane. Probably a semconductor detector would to the trick of measuring the gamma rays. Im not sure how expensive they are but they are definatly more expensiv than any dosimeter (1000-10000 ¤/$).

Hope this was helpfull.

It is calculated according to the sectors flown, average altitude and latitude, flight time and so on.

@I-FORD
These figures would only be correct by normal sun activitys. If theire is a high sun activity those numbers should be higher.

[pax2908]

This may be of interest
http://www.sievert-system.org/
http://www.arcs.ac.at/compsimul/innovlab/projekte/acrem_summary_of_final_report.pdf

This paper has an introduction describing the types (and origin) of particles involved
http://www.estec.esa.nl/wmwww/wma/spweather/workshops/SPW_W3/PROCEEDINGS_W3/solspa1.pdf

[End_of_Descent]

fear_not,

nice post. You should, however, include a some more sources of radiation into your list.

There are high energy particles from outer space and the sun entering the atmosphere (primary radiation), mainly protons and neutrons. There are also cosmic showers created by high energy particles hitting nuclei (oxygen, nitrogen) of the atmosphere, causing huge showers of secondary particles e.g. electrons, muons, pions, kaons and so on.

Cosmic showers are the most important contribution to the radiation in an airplane. They are also the reason why the dose of radiation is higher at high altitudes.

(Alpha, Beta and Gamma ray are usually associated with the decay of a single atom.)

EoD

[fear_not]

End_of_Descent

You are right with the nature of cosmic radiation. The one importand thing witch isnt mentioned yet is what makes a radiation dangerous.

The danger potential in any form of radiation (aplha, beta [and gamma] the exotic) is the potential to ionize the medium through which they travel.
This ionizising potential is interresstingly, low at very high velocity/energy of the charged particles. It only becomes high at lower velocity/energys. Because energy/velocity is lost through by the ionisation of the medium through which they travel the deacceleration of the charged particles is much faster at lower velocity. The distance travled by charged particles where a dangerous high ionization is caused is quit short. It becomes shorter with increased mass of the traveling particle. Thats also the reason why alpha particles arnt that dangerous (high mass).

As far as I know the Muons that are being created by the cosmic radiation have a very high energy and very short lives ( halflife= 2,2 · 10-6 s) , so that nearly all of them decay into electrons(beta minus rays) and positrons (beta plus rays) before they can to any ionization damage.

The Pions deacy into muons and gamma radiation and have a even shorter half live than the muons.

So I believe most of the dangerous radiation at that altitude will be gamma rays caused by the primary shower, exited atoms, secondary showers and decaying neutral pions. The alpha and beta radiation caused at that altitude should not realy pose any threat.

I hope this forum isnt being now abused by me in becoming scientific forum.
Also have to say a disclamer, im doing my masters in materialphysic not in nuclear physic.

[End_of_Descent]

fear_not,

I agree, we should stop and avoid a scientific discussion here ... by chance I work in physics as well. I have a PhD in semiconductor physics which is not nuclear physics as well. :D
Just one more comment, most of the muons are not yet decayed at altitude because of Einstein's time dilatation. So my estimate is that most ionizing particles are still present and gamma radiation is negligile, also because of their low ionization. But I need to do some reading here...

EoD

[fear_not]

End_of_Descent

Im going to see, if I can have a nice chat with somebody who works in that area.


On a different note, I have a friend who began working as a stewardes at austrian airlines.
Aparently they had a special training course about the health risks on flying. In that course the teachers didn' mention anything about radiation risks.
Their even was a question from one of trainees about radiation risk. The reply was, that their isnt any danger at all.

Is this also by other airlines usual. It sounds very reckless to me, if their is no mention to the becoming flightcrew about radiation risks.

After all 2,4 millisievert per year is a unusual high radiation exposure.

I checked the Table about radiation exposure. Annything under 250 millisievert doesnt cause any immidiat effects.

Everything above 250 millisievert can cause measurable immidiat changes in the body.

Anything above 1 sievert (1000millisievert) begins with an accute radiation poisoning. At 2 sievert their is a 10% chance of death in the shortterm (within weeks).

The average radiation exposure of a person living in germany per year is:

2.1 mSv/year exposure thorugh natural Radiation (of which 1/year mSv comes from exposure to Radon [depends on the area])

The maximum unnatural radiation that is alowed for the normal population in germany is 1mSv/year.

The maximum dosis for people working in a workplaces where their is a high exposure to radiation is 20 mSv/year.