[Milsurplus] Clear protective spray on panels?

[Peter Gottlieb]

You are very correct about readings when very close, I have seen this.  
The trouble is, for calibration, finding a strong enough source to have 
an even field strength at a reasonable distance.  Getting the unit 
calibrated is extremely expensive, last I checked, about $350.



WA5CAB at cs.com wrote:
> FWIW, 2 mR/hr is the boundary level at which placards had to be placed when 
> doing industrial radiography, and for instrument calibration benches (or 
> used to be - I haven't kept up with the regs since I stopped having to worry 
> about Cesium, Irridium or Cobalt sources).  Also, when measuring surface 
> conditions, as on a meter glass, it's important to know where in the instrument 
> the detector actually is.  Because the dose rate varies by the inverse 
> square law, at distances under a few inches you can get significantly different 
> readings with different model instruments.
>
> In a message dated 7/3/2009 11:58:14 AM Central Daylight Time, 
> nerd at verizon.net writes: 
>   
>> I have an old altimeter which is pretty "hot" from the radium on the 
>> dial, it gets about 2 mR through the glass.  The thorium mantles for 
>> Coleman stoves will do about 0.5 mR.  Other than that I can measure a 
>> little higher than normal activity from the granite countertops in the 
>> condo I'm renting and that's all I have ever found.  I'm always looking 
>> for examples of radioactivity but not too much around!  (I obviously 
>> don't keep the altimeter close to me!)
>>
>> Btw, I have one of those PDR-27 counters, a later model which is all 
>> solid state.  It hasn't been calibrated but agrees pretty well with one 
>> that was current so it is probably in the ballpark.
>>
>> Peter
>>
>>
>>
>> Michael Tauson wrote:
>>     
>>> On Fri, Jul 3, 2009 at 5:57 AM, Mike Morrow<kk5f at earthlink.net> wrote:
>>>   
>>>       
>>>> Good God...this is the stuff of Art Bell and Mother Earth News!
>>>>     
>>>>         
>>> Ahhh ... but it's good fodder for SF writers too.  God bless the
>>> conspiracy theorists; they keep coming up with cooler story lines than
>>> a lot of authors do.  ;-)
>>>
>>>       
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
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