AW: [ RadSafe ] radiation in therapy room -- [was NRC Says Indian Point, Other Radioactive Leaks Led to Mistrust]

[John Jacobus]

Rainer, et.al.,
The phenomenon that Stewart is probably referring to
is photoneuton activation.  Photons above about 9 Mev
create thermal neutrons by a (gamma,n) reaction. The
neutrons are absorbed to cause neutron activation of
stable isotopes in the treatment room, including those
in the the patient.  

See
http://www.hps.org/publicinformation/ate/q2247.html

The photons are created when the accelerated electrons
creat bremsstahlung radiaton in the tantalum target of
the accelerator.


--- Rainer.Facius at dlr.de wrote:

> Stewart,
>  
> which nuclear reactions with stable nuclei can be
> triggered by 20 MeV electrons creating thereby
> radioactive, i.e. unstable nuclei?
>  
> Rainer
> 
> ________________________________
> 
> Von: radsafe-bounces at radlab.nl im Auftrag von
> stewart farber
> Gesendet: Mo 09.10.2006 05:51
> An: radsafe at radlab.nl; sandyfl at earthlink.net;
> BLHamrick at aol.com
> Betreff: Re: [ RadSafe ] NRC Says Indian Point,Other
> Radioactive Leaks Led to Mistrust
> 
> 
> 
> Hi all,
> Before dismissing the quote out of hand, bear in
> mind we really don't know
> for sure what is being referrred to.
> 
> If by "x-ray equipment" the article is making
> reference to a linear
> accelerator [linac] used in radiation oncology [and
> not just a simple x-ray
> unit used for diagnostic purposes], these linac
> units can put out a steady
> beam of photons in multiple energies of from 6MV to
> 18MV or more [as well as
> electrons in multiple energies up to 20 MeV or
> more]. Linacs can be used to
> irradiate target materials which can make
> radioactive isotopes which could
> theoretically be used for illicit purposes.  Just a
> thought which should be
> recognized.
> 
> Hospitals and therapy centers often upgrade their
> installed linacs and the
> older units are deinstalled and sold in the US and
> abroad.
> 
> Stewart Farber, MS Public Health
> The Prometheus Group, LLC
> [203] 367-0791 [office]
> email: radproject at sbcglobal.net
> 
> ----- Original Message -----
> From: <BLHamrick at aol.com>
> To: <sandyfl at earthlink.net>; <radsafe at radlab.nl>
> Sent: Sunday, October 08, 2006 9:24 PM
> Subject: Re: [ RadSafe ] NRC Says Indian Point,Other
> Radioactive Leaks Led
> to Mistrust
> 
> 
> >
> > My favorite part of the RDD nonsense written is
> the excerpt below.
> > Ummm...good luck with finding radioactive material
> in the x-ray equipment.
> >
> > Barbara
> >
> > In a message dated 10/8/2006 6:20:38 P.M. Pacific
> Standard Time,
> > sandyfl at earthlink.net writes:
> >
> > Scientists responsible for analysing the seizures
> have given warning
> > that traffickers are turning to hospital X-ray
> equipment and
> > laboratory supplies as an illicit source of
> radioactive material.
> >
> >
> >
> >
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+++++++++++++++++++
May we never confuse honest dissent with disloyal subversion. 
Dwight D. Eisenhower  

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com

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