[ RadSafe ] formula and its derivation for rectangular extendedradioa...

Sat Jul 13 01:41:12 CDT 2013

Dear all,
I don't know if this is asked for exactly, but I use a very simple equation
to estimate doses from containers full of minerals. All one needs is the
surface dose rate - which is better to be measured (but can, of course be
estimated as well).  It goes like that:

EDR = EDRsurface × [1 – d/(d2 + A × B/3.14)0.5]

All in meters: d – distance to the source, A – height, B – width.
Seems to work rather nicely when the surface dose rate is above 5-6
microSv/hour, and takes about a minute or less to estimate.  But I honestly
have no recollection by now where did I get it from...  If anyone has a
reference to this - I'll very much appreciate it.
Kind regards
Nick

On Sat, Jul 13, 2013 at 2:00 PM, <JPreisig at aol.com> wrote:

> Mike Brennan/Radsafe:
>
>       That's an interesting idea.
>
>       MCNP modeling shouldn't take a week, if one  already has MCNP on a
> PC.  And PC's these days are
> so very powerful.  Problem setup for a rectangular source should take
> about one day, and a first MCNP
> run should take 4 to 8 hours or less.  Perhaps then, one can directly
> compare these Monte Carlo results with your measurements.
>
>      In the olden days, I sure would like to have come  up with an analytic
> and/or numerical solution.  Solving problems this way  forces one to
> seriously understand the problem.  The book on Mathematical  Physics by
> Arfken
> might be real helpful for getting an analytical or numerical  solution.
>  The
> book Numerical Recipes by
> Press, Teukolsky et al. has many different numerical solution algorithms,
> complete with Fortran or C
> computer code.
>
>     Pick a solution method or two and get cranking.   You can't use MCNP on
> the CHP exam!!!!
>
>     Joe Preisig
>
>
>
>
> In a message dated 7/12/2013 5:05:48 P.M. Eastern Daylight Time,
> Mike.Brennan at DOH.WA.GOV writes:
>
> I know  this is rather old school, but if the source really exists, and
> there are  actually people who do things near it, how about a
> "tag-and-release"  dosimetry program?  Sometimes a day of measurement can
> replace a week  of modeling.
>
> -----Original Message-----
> From:  radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu]  On Behalf Of dcoble tds.net
> Sent: Friday, July 12, 2013 12:15 PM
> To: The  International Radiation Protection (Health Physics) Mailing List
> Subject:  Re: [ RadSafe ] formula and its derivation for  rectangular
> extendedradioa...
>
> Micro shield tm  works  also.
>
> On Friday, July 12, 2013,  <JPreisig at aol.com>  wrote:
> > Radsafe:
> >
> >       I know this  is overkill or too expensive or  time consuming for
> > some  people/facilities, but one could readily set up a  rectangular
> >  radiation source using MCNP (Monte Carlo Neutral Particle Program)
> > and do a Monte
> Carlo
> > Run (or a few) and solve the  problem.  Do some of the  simpler
> > computer radiation codes  model a rectangular source????
> >
> >       Regards,   Joe Preisig
> >
> >
> >
> >
> > In a  message dated 7/12/2013 2:36:29 P.M. Eastern Daylight Time,
> >  daniel.s.simpson at nasa.gov writes:
> >
> >  George:
> >
> >
> >
> > I don't see a WORD file   attached.
> >
> >
> > Daniel S. Simpson
> > Deputy Chief, Code  350 Occupational  Safety & Health Division National
>
> >  Aeronautics and Space  Administration Goddard Space Flight Center
> >  Greenbelt, MD   20771
> > (301) 286-2281
> > Fax: (301) 286-1745
> >
> >
> >
> > -----Original   Message-----
> > From: radsafe-bounces at health.phys.iit.edu
> >  [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of George
> > Chabot
> > Sent: Friday, July 12, 2013 2:22 PM
> > To: 'The  International  Radiation Protection (Health  Physics)
> MailingList'
> > Subject: Re: [ RadSafe ]  formula and  its derivation for rectangular
> > extended radioactive sources   exposure rate
> >
> >
> >
> > Regarding the rectangular  source, attached is a  Word document showing
>
> > the equation  development. It is not possible to obtain a  complete
> > algebraic  solution to the required integration, but the resulting
> >  equation is
> easily
> > solved using numerical  integration.
> >
> >
> >
> > George   Chabot
> >
> >
> >
> > -----Original  Message-----
> >
> > From:
> >  radsafe-bounces at health.phys.iit.edu<mailto:
> radsafe-bounces at health.phys.iit.edu>
> >
> >  [mailto:radsafe-bounces at health.phys.iit.edu]  On Behalf Of Danak,
> > Subhash
> M
> > CTR DOD CAPMED FBCH
> >
> > Sent:  Thursday, July  11, 2013 10:28 AM
> >
> > To:   radsafe at health.phys.iit.edu<mailto:radsafe at health.phys.iit.edu>
> >
> >  Subject:  [ RadSafe ] formula and its derivation for rectangular
> >  extended radioactive  sources exposure  rate
> >
> >
> >
> > I like to review formula for  rectangular  radioactive sources exposure
> rate.
> >
> > Please  provide one.
> >
> > I thank   you.
> >
> >
> >
> >  Subhash
> >
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