[ RadSafe ] RE: Thermal neutron counting

Tue Apr 11 12:27:18 CDT 2006

Don,

LiF is very good at this.  TLD-700 and TLD-600 chips could be used to
measure background and actual Nth counts at the same time, in the same place
(as TLD-700 is "insensitive" to thermal neutrons).  You would probably want
to quantify the TLD-700 insensitivity anyway.  You could also do this with
TLD-100 dosimeters which are sensitive to thermal neutrons as they contain
natural abundance Li-6 and are less sensitive to thermal neutrons. 

Another tactic would be to use a radiator, where you put LiF or boron onto a
plastic material like CR-39 and measure the pits created by dissolution of
Li-6 and fragments creating pits on CR-39 (which would then be developed).

Another method may be to look at activation of metals.  I guess it depends
on the field you are looking at and how low a dose you need to measure.  One
problem with activation is that you have to assume the fluence is constant
and do a production rate and decay rate to find where you are in achieving
equilibrium.

Good luck,

Rob

Robert J. Gunter, CHP
CHP Consultants
Oak Ridge, TN
Ph:  (865) 387-0028
Fax: (865) 483-7189
rjgunter at chpconsultants.com
Products and Services at:
www.chpconsultants.com

Message: 11
Date: Mon, 10 Apr 2006 09:28:53 -0700
From: "Mercado, Don" <don.mercado at lmco.com>
Subject: [ RadSafe ] Thermal Neutron Counting
To: radsafe <radsafe at radlab.nl>
Message-ID:
	<3D92CA467E530B4E8295214868F840FE81F699 at emss01m12.us.lmco.com>
Content-Type: text/plain; charset=us-ascii

Greetings all,

A researcher here approached me this morning wanting to count thermal
neutrons around a device for a month. He says that there can't be any
power/electronics involved with the detector. I thought of activation
foils and I'm working with our dosimetry company to see what they can do
for us, but I thought I'd come to the well for advice.

What would you suggest for counting thermal neutrons in this case? Any
help would be greatly appreciated.

Donald P. Mercado
Radiation Safety Officer
Explosives Safety Officer
Lockheed Martin Space Systems Company
O/9K-2S, B/157
1111 Lockheed Martin Way
Sunnyvale, CA 94089
Ph. (408) 742-0759
Fx. (408) 756-0504
Don.Mercado at lmco.com
"Life is not a journey to the grave with the intention of 
arriving safely in a pretty and well preserved body, but 
rather to skid in broadside, thoroughly used up, totally 
worn out, and loudly proclaiming 
-- WOW!!! -- What a Ride!!!"

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

Message: 13
Date: Mon, 10 Apr 2006 10:32:23 -0700
From: "Sandy Perle" <sandyfl at earthlink.net>
Subject: Re: [ RadSafe ] Thermal Neutron Counting
To: "Mercado, Don" <don.mercado at lmco.com>,
	radsafe at radlab.nl
Message-ID: <443A3437.3250.CAEDA9 at sandyfl.earthlink.net>
Content-Type: text/plain; charset=US-ASCII

On 10 Apr 2006 at 9:28, Mercado, Don wrote:

> A researcher here approached me this morning wanting to count thermal
> neutrons around a device for a month. He says that there can't be any
> power/electronics involved with the detector. I thought of activation
> foils and I'm working with our dosimetry company to see what they can do
> for us, but I thought I'd come to the well for advice.
> 
> What would you suggest for counting thermal neutrons in this case? Any
> help would be greatly appreciated.

Are you looking for an actual dose from the thermal neutrons? If so, 
TLD is extremely sensitive to thermal neutrons.

-------------------------------------
Sandy Perle
Senior Vice President, Technical Operations
Global Dosimetry Solutions, Inc.
2652 McGaw Avenue
Irvine, CA 92614 

Tel: (949) 296-2306 / (888) 437-1714  Extension 2306
Fax:(949) 296-1144

E-Mail: sperle at dosimetry.com
E-Mail: sandyfl at earthlink.net 

Global Dosimetry Website: http://www.dosimetry.com/ 
Personal Website: http://sandy-travels.com/ 

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

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