GOOD RESOURCE: Radiation Network

     Thank you, Kathryn Roux Dickerson, friend and researcher par excellence! Kathryn sleuthed out exactly what I've been looking for, a site with no government connection or political agenda, which gives actual numerical readings from Geiger counters (in the hands of volunteers) around the country.
     Isn't good ol' Yankee ingenuity wonderful--oops, Kathryn, let me hastily correct that to read American ingenuity!

Radiation Network is a fire hose of everything you want to know about radiation. It is overwhelming unless you take it step by step. (You can start with the link to Message at the top--or just start reading the presenting page. If you find yourself starting to hyperventilate, slow down.) The subject is far more complicated than I had feared but this site makes it clear if you don't panic. (I have to tell you, when I Googled "half-life" the other day to give you an accurate definition and found it headed "PHYSICS" I panicked! All I know about physics I learned in a 6-week summer course on the physical sciences at Portland State University, to meet my B.A, requirement--and each of those sciences was covered in one of those weeks. (We rolled a ball bearing down an incline, we fingered talc--uh, that's all I remember.)
     I remember our teacher giving us a quiz that included the statement, "Physical science is easy and fun. T or F" At the end of the six weeks one of my friends asked me, "Well, was it easy and fun?" I took the binder of class handouts and my notes, dropped it in the wastebasket and said, "It's easy and fun and FINISHED." If I had had any idea I was studying physics when I tried to broaden my miniscule knowledge of radiation I would have freaked out.)

Helpful quotes from the US Radiation Map website:
   The numbers represent radiation Counts per Minute, abbreviated CPM, and under normal conditions, quantify the level of background radiation, i.e. environmental radiation from outer space as well as from the earth's crust and air.  Depending on your location within the US, your elevation or altitude, and your model of Geiger counter, this background radiation level might average anywhere from 5 to 60 CPM, and while background radiation levels are random, it would be unusual for those levels to exceed 100 CPM.  Thus, the "Alert Level" for the National Radiation Map is 100 CPM, so if you see any Monitoring Stations with CPM value above 100, further indicated by an Alert symbol over those stations, it probably means that some radioactive source above and beyond background radiation is responsible.
Alert Level - You are an astute group!  A few of you already noticed that we recently lowered the Alert Level for the Map from 130 to 100 CPM.  It was probably too high in the first place.  The optimal setting for a Radiation Alert is one that is not so low as to invite false alerts from momentary spikes in radiation, yet not so high as to defeat its original purpose.

 

Units of Measurement - It is confusing - Rems, Rads, Roentgens, Sieverts, CPM, mili, micro... In the US, the standard unit to quantify dosage is the Roentgen, or more particularly, usually milli-Roentgens per hour, abbreviated as mR/hr, or micro-Roentgens per hour, written as uR/hr.

     Meanwhile, in Japan and most other countries, the common unit is the Sievert, and in practice usually micro-Sieverts per hour, written as uSv/hr.  It is easy to convert - 1 mR/hr equates to 10 uSv/hr, so a reading out of Japan of 500 uSv/hr would equal 50 mR/hr - just divide by 10.  Some people use the term Rads or Rems as substitutes for Roentgens, and for all intents and purposes, they are interchangeable, although not scientifically correct.

     A cautionary note - because of the large array of radiation units, when stating a reading, it is meaningless, dangerous, and irresponsible to give just the number - always follow that number with the corresponding unit of measurement - not doing so breeds wild rumors.

     But the Radiation Map uses CPM - why?  Well, because CPM, or Counts per Minute, corresponds directly to the output of the compatible Geiger Counters, and CPM levels are also user-friendly integral numbers. . .

Note: If I am sexist shoot me but in my opinion any mathematical conversions like the ones above require a husband. 

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