Current Radiation Intensity
http://en.wikipedia.org/wiki/Geiger_counter tells you how much radiation is in the environment you are in.
Kearny Fallout Meter
The http://en.wikipedia.org/wiki/Kearny_Fallout_Meter designed as part of the Nuclear War Survival Skills package, well tested and calibrated, can be made relatively simply. This is a well-proven but simple scientific instrument.
Total Radiation Exposure
http://en.wikipedia.org/wiki/Dosimeter measures the total cumulative exposure to radiation over time, which roughly correlates to health impacts.
improvised film dosimeter
http://en.wikipedia.org/wiki/Film_badge_dosimeter
Is it possible to use an unexposed roll of 35mm film carried in one's pocket as an improvised equivalent of the film badge dosimeter? Issues include
- the film badge dosimeter is professionally produced and calibrated
- rolls of 35mm film may be far, far too variable in either thickness of metal and plastic coating, or film sensitivity to be calibrated accurately to actual radiation exposure
- even if the improvised film dosimeter can be calibrated to actual radiation exposure there is a severe problem - see "measuring the right thing" below
Can anybody with access to proper dosimeters, radioactive sources and a lab take a crack at calibrating some common 35mm film cannisters with standard industrial safety equipment to see if any useful data can be gathered about personal exposure from a 35mm film roll?
Measuring the Right Thing
Dosimeters cannot accurately predict damage from radiation in situations where you have things like burning nuclear fuel for the following reason. There are three kinds of radiation - alpha, beta and gamma. Alpha and beta will be mostly absorbed by thin layers of metal and plastic, but gamma will pass straight through. A dosimeter, therefore, mostly measures gamma rays. However, most of the long term health impact from exposure to nuclear accidents is done by accidentally inhaled particles of radioactive material which then lodge in the body. Once in the body, the alpha and beta emissions from the lodged particles do not show up on the dosimeter.
Therefore, the dosimeter indicates the *minimum* level of radiation to which a person has been exposed, **not the maximum level** and therefore may not be all that useful for estimating exposure. However, being able to reliably estimate minimum exposure may be useful in catastrophic situations where people are working in contaminated environments without proper dosimeters or safety equipment - a truly catastrophic scenario, such as a terrorist nuclear weapon.