RE: Looking for vendor-polyethylene pig for neutron source

["Dr Christoph Hofmeyr" <chofmeyr@nnr.co.za>]

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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