LLRC: Advice on Geiger counters

People are asking for advice on Geiger Counters. In this emergency anything is better than nothing. There are lots of Russian Geiger Counters on ebay.
You need one that will measure down to background levels. This means it needs to be able to display 0.05microSieverts (50nSv) or MicroGrays (mGy) per hour. Background should be about .05 to 0.1 microSieverts per hr. Thats 0.005mR to .01mR/h (Rem Roentgen)
Do not worry about calibration (see footnote).
Don’t wait until you think the fallout might have arrived. Take readings outdoors immediately to establish the baseline value of what’s normal for your area. Note down the readings. Ideally, email us and tell us where you are and what your baseline reading is.
Keep taking readings regularly – several times a day. Don’t panic if there’s a small increase when it rains – that’s normal. Take avoiding action (see below) if the reading increases to double the baseline value and at that point inform us.

NOTE: We have said Geiger Counters cannot measure or detect the presence of alpha emitters like Plutonium and Uranium or beta emitters like Tritium and Strontium 90. This remains true but it is very likely that those contaminants will arrive together with gamma emitters like Caesium 137 which act as a flag. To put it another way, if the gamma signal increases, make the precautionary assumption that you are detecting the whole cocktail of radionuclides from the reactor and from the spent fuel rods that have been blown into the air or burned. Take what action you can:-
·        stay indoors and keep doors and windows shut.
·        Drink bottled water (even if it’s only tap water that you drew off and stored before the fallout arrived),
·        use tinned milk,
·        don’t eat local produce unless it was harvested earlier.

Footnote on calibration: Purists and pro-nuclear critics will bitch about calibration (i.e. standardizing your instrument against a known radiation source). You must not worry about it. This is about public protection, so accurate values are nowhere near as important as any variations you find measured on your monitor. So long as you keep using the same Geiger Counter you have a reliable way of spotting the changes.

By piotrbein


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