[ RadSafe ] Calculate Dose from Flash X-ray?

[JPreisig at aol.com]

Hi,
 
      I suspect MCNP can model (Monte Carlo  Neutral Particle Program) , 
your problem.
Buy MCNP and learn how to use it or find someone who will run the problem  
for you. 
 
      I'm not sure if MCNP can compute the X-rays  coming off the target.  
Try EGS???
 
      
Your problem is  essentially a beam of electrons striking a target of known 
geometry, and you  want
to find Roentgens/rad/rem (maybe someday I'll go SI) at some distance from  
the target.
I expect, if I had MCNP running right now, that I could set up the problem  
geometry in about
one day.  I probably could get you computational run results in about  a 
day or two later.
 
     Nowadays, with my current PC, the runs might take  10 minutes to 
several hours.  Back about
14 years ago, a run would probably take a full evening.
 
      One can set up an MCNP tally (Monte Carlo  modelling) detector at 
various positions of 
interest, one meter away (or whatever) from the target.  In MCNP  you would 
specify the distance
and various angles (or x,y,z position) from the target.
 
      One would also have to specify the  characteristics of the electron 
beam source, which you
seem to know.  I think MCNP has the ability for the user to supply a  time 
dependent source term of
electrons.  If not, you could run MCNP multiple times with source on  and 
source off?
 
      Heck, you could model neutrons in a reactor,  using MCNP's repeated 
structures
capability.
 
      And you could even do some crude modelling  of initiation of a 
nuclear device, if all the cross
section data is available.
 
     Fermi probably would have really liked to have a  copy of MCNP back 
then.  I've read, he used
to do Monte Carlo calculations in his head at night (too much  expresso???).
 
     For more nuclear fun, google search on:   calutron, diffusion, 
centrifuge and uranium,
strong focusing, alternating gradient, etc.  
 
     Oh sometimes channeling has to do with people  trying to channel to 
other beings???
The nuclear meaning of channeling can be found in the nuclear physics book  
by Segre.
It has to do with directing a beam of electrons or protons (or  whatever) 
along the principal???
axes??? of the crystal, and seeing what happens.  See gamma laser  also???
 
 
      Regards,    Joseph R. (Joe)  Preisig, PhD
 
 
     
 
 
                                 In a message dated 8/12/2011 7:00:43 P.M. 
Eastern Daylight Time, tdc at xrayted.com  writes:
 
That's a  pretty hefty x-ray machine!!  Assuming it can go CW - which I 
very  much doubt.

So - what do you mean by "beam strength"?  Average  rate within the pulse 
is pretty straight forward - ie, trivial - but  surely the pulse is not 
"flat" - I assume this is a CD unit or some sort  of "flash x-ray 
machine".  For anything other than that you did not  supply enough 
parameters.

Tells us what you want - and we can tell  you what additional parameters 
are needed.

On 8/11/2011 9:55 AM,  Bill Miller wrote:
> The vendor said the measured dose at 1 meter from a  450 kV, 6000 A X-Ray
> unit with a 25 nanosecond burst is 18  milli-R.  Is there a way to 
calcualte
> the expected beam strength  from this unit?  thanks
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