[ RadSafe ] " Technology to detect radiation has progressed "

[Jim Hardeman]

Steven --
 
Good point. Even the best gamma spectroscopy algorithm is going to make an erroneous identification, and if the user has only enough training to blindly assume that the nuclide ID is correct, you can get yourself into a world of trouble. As an example, we were evaluating one of the new (I'm not going to use any brand names) rad-pager / nuclide ID combination units a while back -- in addition to the standard NaI probe used to DETECT elevated radiation, the unit also uses a small CZT detector to IDENTIFY the radionuclide(s) present.
 
One of my standard acceptance tests is to look at a red / orange FiestaWare platter -- makes a great check source w/ a contact radiation level of ~50 uR/hr. I placed this unit on top of the platter and set it to count -- it took 10 minutes to acquire a spectrum (vs. 1 for more of the handheld units we use) and then only identified U-235 -- where most other units I've used would either return U-Nat or both U-238 and U-235 in roughly the correct proportions w/ a 1-minute count.
 
This instrument is being marketed to law enforcement folks -- folks who would normally wear only a rad pager, and then would have to call someone else to back them up w/ nuclide identification. I'm not sure, however, that at slightly elevated radiation levels even the most qualified gamma spectroscopist could make an accurate assessment. The only thing preventing these things from hanging on every street cop is the COST. I shudder to think what would happen should a similar mis-identification occur in the field ...
 
What hasn't been said yet in this chain is how these nuisance radiation alarms affect state radiation control programs. In most states, the state radiation control program is responsible for investigating findings of elevated radiation in the environment -- whether it's a trash truck at the gate of a landfill, a load of scrap metal that set off the detector at a steel mill, or (if we ever find out about it) a hit during a security sweep. Radiation is one of those things where "the more you look, the more you're going to find" -- and if you have a small, static group of folks equipped and trained to go in after detection to assess what you've actually detected -- and then you increase detection capability w/o also increasing the capability to assess and identify, you're going to run those folks ragged "chasing gnats" -- not that I would know anything about that <sigh>
 
Of course, all this is my $0.02 only ...
 
Jim Hardeman
Jim_Hardeman at dnr.state.ga.us 

>>> Steven Dapra <sjd at swcp.com> 8/23/2007 21:17 >>>
Aug. 23


At 09:12 AM 8/23/07 -0500, Geo>K0FF wrote:

>----- Original Message ----- From: <nssihou at aol.com>
>To: <idias at interchange.ubc.ca>; <neildm at id.doe.gov>; <sjd at swcp.com>; 
><brent.rogers at ansto.gov.au>; <radsafe at radlab.nl>
>Sent: Thursday, August 23, 2007 6:17 AM
>Subject: Re: [ RadSafe ] " Technology to detect radiation has progressed "
>
>>
>>Most scrap yards now have radiation monitors and check metal as it enters 
>>the site. Unfortunately, the radioactive material is not always seen if 
>>shielded by a lot of other steel scarp. Texas has had several source? 
>>melts over the last few years. Before radiation monitors, I'm sure lots 
>>of radioactive incidents went undetected.

[edit]

>>The bigger problem is that we have larger and larger numbers of radiation 
>>monitoring devices and fewer and fewer qualified persons operating them.
>
>**(Geo) Correct, this is part of a learning curve issue, and will be 
>addressed by smarter equipment, not by better trained personnel. And so it 
>goes.
>Check Radsafe Archives for comment by J. Marshall Reber on this subject.

         Smarter equipment can not take the place of better trained 
operators.  Operators are needed who can interpret what they see (detect) 
and --- we hope --- apply some reasoning power to it.  Arbitrarily relying 
on equipment may cause more problems than it will solve.  Can a machine 
tell when it has a false positive?  Can it distinguish between NORM and the 
dreaded "dirty bomb"?  What happens when a car carrying a cancer patient 
who has undergone rad therapy goes past the detector?  (That's how this 
thread got started.  Remember?)

Steven Dapra
sjd at swcp.com 


_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood the RadSafe rules. These can be found at: http://radlab.nl/radsafe/radsaferules.html 

For information on how to subscribe or unsubscribe and other settings visit: http://radlab.nl/radsafe/