[ RadSafe ] Taiwan/rebar etc.

JPreisig at aol.com JPreisig at aol.com
Thu Mar 22 07:15:27 CDT 2012

     From:    _jpreisig at aol.com_ (mailto:jpreisig at aol.com)    .
     Dear Radsafe:
             I  hope any study done about the rebar containing Co-60 or 
whatever, has included  the 
shielding effects of the concrete around the rebar.  Yes, concrete  isn't 
great shielding material for 
Co-60 gammas, but the concrete shielding effects must be modelled or  
accounted for.
            Such a  problem could easily be modelled using MCNP (Monte 
Carlo Neutral Particle
Program).  The problem could be setup in a few days and the first  results 
would be generated
in the next few days after that.  Sounds like a nice grad student  project. 
 MCNP is available
through Los Alamos, RSICC (ORNL) or perhaps via the internet.  It can  
handle neutron and/or
gamma/photon problems.  MCNPX or whatever now extends the modelled  energy 
range of neutrons
etc. well above 20 MeV.
            A long,  moderately warm Summer is coming here in the USA???
Oaxaca, Mexico earthquake (magnitude 7.4) happened in the last few  days.
           Be  good...     Regards,    Joseph R. (Joe)  Preisig, PhD
PS   For S. Perle and you folks at Mirion, perhaps you might want  to look 
into bubble dosimeters
       as a means of doing neutron  badging.  I remember seeing a graph of 
bubble dosimeter response,
       and that it went from thermal energies  to about 15 MeV.  Bob Apfel 
and/or that
       gentleman up in Canada were both  involved in neutron bubble 
dosimetry.  I don't think Dr.
       Apfel is still around????
                One could probably use a CCD (Charge Couple Device) or 
perhaps some modern 
       mini-camera to have the badge user do  badge counting at their 
location???  Then use modern
       algorithms to find actual neutron dose  equivalent.  The new Mirion 
dosimeter system can clearly
       be still used to arrive at any  gamma/photon component.  Good 

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