fixed tritium contamination

["Les Slaback, Health Physics" <SLABACK@micf.nist.gov>]

Detecting fixed tritium contamination depends (of course) on the object and     
 surface and the desired sensitivity.  All of the following are possible        
candidates:                                                                     
                                                                                
1. windowless survey instrument (flat clean surface, no other radiation)        
                                                                                
2. windowed detector to see the x-rays produced by the tritium betas            
     (poor sensivity, calibration depends on the material and depth distr.)     
                                                                                
3. helium detector like DoE and Eberline have produced, reported to be very     
sensitive (object must be small enough to fit in the chamber)                   
                                                                                
4. destructive sampling                                                         
                                                                                
Any other suggestions/methods?                                                  
                                                                                
Assaying/estimating the TDO content of the primary heat exchanger tubes         
when we disposed of our heat exchanger (from a heavy water reactor) was         
certainly a challenge.                                                          
                                                                                
SLABACK@MICF.NIST.GOV  [NBSR Health Physics Group]                              
    ...a little risk, like a bit of spice, adds flavor to life                  
                                                                               
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