Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!ig!ames!lll-lcc!rzh
From: rzh@lll-lcc.UUCP (Roger Hanscom)
Newsgroups: sci.electronics
Subject: Radiation Detectors
Message-ID: <2449@lll-lcc.UUCP>
Date: 26 Apr 89 19:01:52 GMT
Organization: Lawrence Livermore Labs, LCC, Livermore Ca
Lines: 39


  I'm not a radiation physicist, but I have had some experience with some
of the issues discussed in "Radiation Detectors/Counters" by neal@lynx.UUCP
(Neal Woodall)

  The radiation sciences have an interesting problem.  While particles
and radioactive decay are relatively easy to measure and the units used
in these measurements can be readily defined, the effects of these
phenomena on human tissue are much more complex and poorly known.  REMs
vary with the tissue that is exposed to radiation.  Hands, limbs, etc
can take higher levels of REMs than gonads, for instance.  It is my
understanding that there are government defined threshold levels of
radiation dosage, but there is often no real knowledge, proven over
extended periods of time, of whether these levels are appropriate --
or even safe.  There is probably some variability, between organisms,
as to what "safe" levels are.  So, when you are in the realm of particles
and radiation, it is a hard science.  When considering the effects
on living organisms, things are less concrete.  However, one can say
(bogus numbers here, just an example) that 100 gigachurps will kill
a human, but 10 won't.  At least you won't die on the spot, but will
exposure to 10 kill you in 30 years?  Does anybody *really* know?
And, even worse, where does the government draw the line between 10
and 100 as the "safe" threshold?

  On radioactive mineral specimens:  The radiation from them is one
thing to be careful of, but I'd be more concerned with the by-products
of their radioactive decay .... radon and other nasties, for example.
When I was a graduate student, Cliff Frondel (one of *THE* experts
on rare radioactive minerals) had a row of cabinets in his office
(in the Museum there at Harvard University) that housed one of the
world's most complete collections of naturally radioactive materials.
He was in his office a lot.  The Health Services people looked it over, 
and only forced him to install an exhaust fan nearby!  Are there any
mineralogists out there??  Is Cliff still alive (he was approaching
retirement age at the time -- 20 years ago)?  

        roger         rzh%freedom.llnl.gov@lll-lcc.llnl.gov
                      ucbvax!lll-lcc!freedom!rzh
    Upstairs, Over a Vacant Lot, Inc.