RE: 38,222CPM

["Bob Scott" <bscott@4scotts.net>]

I haven't seen anyone on this thread try to determine the activity of

this specimen in Ci, so here's a 'rough and dirty'.



With a count rate stated at 38,222 cpm, if we accept this as a real

number and not just made up, then we know that the tester was using a

count rate meter, not a simple survey meter.  We don't know the count

time, so a simple square root of the count rate gives a SD of about 200

cpm.  If we assume that the count rate meter had an end-window GM

detector connected, then for mixed gamma-beta we could suggest an

efficiency between 5% and 15%, so for the fun of it, call it 10%

efficient.  So maybe we're seeing 400,000 dpm.  There's a lot of

backscatter, sidescatter and self-absorption (all depending upon the

counting geometry and size of rock).  Just for the fun of it, lets say

that on or near the surface of this specimen there might be 4,000,000

dpm.  At 2.22 E6 dpm / microcurie, you might have on or near the surface

of this rock maybe 2 microcuries.  It almost certainly is naturally

occurring radioactivity.



> 

> >Hey folks:

> >

> >Just a quick question; What type of rock would exhibit 38,222CPM?



	You obviously have to see the rock and classify it by

appearance, not by the amount of activity contained in it, to determine

its type.



> >Could this be a rock with a vein of ore such as Uranium (any

variety)?

> >Could this rock be from Western New York State?

> >Would this "rock" 



	Why did you use quotes on "rock" here?





> >be considered radioactively "hot" and would it present

> >a danger say if handled and then went to lunch without washing ones

hands?



	By my earlier calculation, this would not be a hot rock, and it

would not present a danger if handled.



> >How would I properly dispose of this specimen?



	Take it out in your garden and use it as edging.  Or put it in

the trash so that it can go to the landfill or wherever your trash is

taken.



Bob Scott 







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