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Re: Looking for vendor-polyethylene pig for neutron source
We used to us paraffin in the oil biz, but the fire hazard required a
changed to boron foam.
Syd
----- Original Message -----
From: "Dr Christoph Hofmeyr" <chofmeyr@nnr.co.za>
To: <twicklan@middlebury.edu>
Cc: <radsafe@list.vanderbilt.edu>
Sent: Tuesday, November 11, 2003 2:21 AM
Subject: RE: Looking for vendor-polyethylene pig for neutron source
> Bobby,
> Traditionally a sturdy drum filled with wax (optional borax added) was
often used with a source-sized hole down the middle to store a neutron
source. If that is considered a fire hazard, water (again with borax
optional) could be considered. If most of the (thermalized)neutrons are
captured in boron, the gamma energy is about 480 keV, compared with the
rather penetrating 2.22 MeV if captured in hydrogen.
> Chris Hofmeyr
>
> -----Original Message-----
> From: Bobby Faulkner [mailto:bfaulkner@premiertechnology.cc]
> Sent: 10 November 2003 07:54
> To: Wickland, Tim; radsafe@list.vanderbilt.edu
> Subject: RE: Looking for vendor-polyethylene pig for neutron source
>
>
> Mr Wickland,
>
> Try Thermo Electron Corporation http://www.neutron-shielding.com/
> I have used their products for applications requiring neutron shielding
> on many occasions. [5% Boron-Polyethylene excellent attenuation of thermal
> neutrons and significant reduction of capture-gamma dose].
>
> Regards,
>
> Bobby Faulkner
> Project Engineer
> (208) 238-5531
> Premier Technology, Inc.
> http://www.premiertechnology.cc
> Tim,
> Traditionally a sturdy drum filled with wax (optionally with borax mixed
in) with a source diameter hole down the middle has been used to good
effect. If this is regarded as too much of a fire hazard, water (optionally
with borax) can be considered. The capture of a thermalized neutron in
boron gives a softish 480 keV gamma, while capture in hydrogen results in a
penetrating 2.22MeV gamma. For the same reason borated polythene is
preferable.
> Chris Hofmeyr
> chofmeyr@nnr.co.za
>
> -----Original Message-----
> From: Wickland, Tim [mailto:twicklan@middlebury.edu]
> Sent: Friday, November 07, 2003 2:57 PM
> To: 'radsafe@list.vanderbilt.edu'
> Subject: Looking for vendor-polyethylene pig for neutron source
>
>
> We are in the process of leasing a 1 mCi Cf-252 sealed neutron source from
ORNL under its university loan program. At first we thought that we would be
allowed to keep the lead-lined polyethylene pig the source ships in, but now
we're told we must return it as soon as we receive the source.
>
> Does anyone know of a vendor who carries such a pig ready-made? Or are we
going to have to make our own?
>
> We're also looking for a source of polyethylene bricks, or are these also
a make-it-yourself item?
>
> Thanks for any info you can provide.
>
> Timothy H. Wickland
> Director, Sciences Support Services
> Bicentennial Hall 333
> Middlebury College
> Middlebury, VT 05753
>
> twickland@middlebury.edu
> (802) 443-5421 (voice)
> (802) 443-2072 (FAX)
>
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