Airport dosimetry - Reply

["Ryge, Peter" <peter@ancore.com>]

The SAIC EDS-3 thermal neutron explosive detection system contains a 
Cf-252 source of up to 150 ęg located below the bag in a moderator.  Bags 
move rapidly through on a conveyor belt, exposing the bag to the maximum 
flux for about a second or so.  The estimated fast neutron fluence at the 
bag is about 2.5e5 n/cm2 and thermal about 4.5e5 n/cm2, which converts to 
about 20 mrem using table 1004(b).2 of 10CFR20.1004.  A gamma/x-ray 
personal dosimeter shows about 1mR per pass.

The EDS-3  was developed and built by the Advanced Nucleonics Division of 
SAIC  which is a separate company as of Nov 1, 1997 called Ancore 
Corporation, affiliated with and partly owned by SAIC.  Ancore is 
continuing its work, especially in automatic non-intrusive inspection for 
concealed explosives, drugs, and other contraband.  

Six EDS-3 systems were built and operated in various airports for a year 
or two each, ending in 1994. None is presently deployed.  I am not aware 
of any other neutron-based inspection system being used in airports. 

Please contact me if you have further questions.

Peter Ryge, VP Engineering, Alt. RSO
Ancore Corporation
2950 Patrick Henry Drive, Santa Clara CA 95054
tel: 408/727-0607   fax: 408/727-8748
email: peter@ancore.com   http://www.ancore.com