Re: A "dirty bomb" question

[Dimiter Popoff <tgi@cit.bg>]

 The 241Am 59.5 keV gamma peak is well pronounced (apr. 36% yield), there are

also some with much lower yield at lower energies (apr. 2.3% @ 26 keV

etc.).

 However, the 241Am smoke detector sources I have seen are mounted in a

thick brass housing which would probably make them undetectable

with a GM tube. A source which was doing 40 kCpS on a Ge detector,

when turned with the brass side to the detector was de facto invisible

(well, I did not have the patience to collect an hours spectrum on that,

I was using and not evaluating the source). Anyway, the GM counter

is unlikely to be very useful around a closed smoke detector.



Dimiter



--------------------------------------------------------------------

Dimiter Popoff

Transgalactic Instruments, Gourko Str. 25 b, 1000 Sofia, Bulgaria

http://transgalactic.freeyellow.com











> From: "Syd Levine (AnaLog)" <AnaLog@logwell.com>

> Cc: <radsafe@list.vanderbilt.edu>

> Subject: Re: A "dirty bomb" question

> Date: Tue, 28 Oct 2003 11:22:46 -0600

>

> True, but it also puts out a 59.5 meV gamma, and I think a 14 meV gamma as

> well.  The 59.5 meV gamma is handy for setting the discrimination circuit in

> gross count scintillation gamma ray oil well logging tools.

> 

> Syd H. Levine

> AnaLog Services, Inc.

> Phone:  270-276-5671

> Telefax:  270-276-5588

> E-mail:  analog@logwell.com

> URL:  www.logwell.com

> 

> ----- Original Message ----- 

> From: "Thomas M Lashley" <lashleyt@DTEENERGY.COM>

> To: "Richard L. Hess" <lists@richardhess.com>

> Cc: <radsafe@list.vanderbilt.edu>

> Sent: Tuesday, October 28, 2003 6:29 AM

> Subject: Re: A "dirty bomb" question

> 

> 

> > I thought ionization smoke detectors used an alpha source like

> americium-241.

> >

> > Tom Lashley

> > mailto:LashleyT@DTEenergy.com

> >

> > "Richard L. Hess" wrote:

> >

> > > I don't know about this smoke detector thing. I have two models of smoke

> > > detectors in my house--both must be photoelectric--because my CDV-700

> > > didn't click more near them (with the beta shield open) than away from

> them

> > > and it seems to be working and reasonably calibrated based on the

> uranium

> > > check source on the side.

> > >

> > > Cheers,

> > >

> > > Richard

> > >

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