Richard Bindel1, Lei Cao1,2, Heather Chen-Mayer3, Rick Paul1,

and Elizabeth Mackey1


1 Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA


2 Department of Material and Engineering, University of Maryland, College Park, MD 20742, USA


3 Physics Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA


Prompt gamma-ray activation analysis (PGAA) provides a non-destructive means of simultaneously determining the presence and amount of various elements in a sample.  The technique is relatively insensitive to the physical form of the sample, and no special preparation, e.g. dissolving, atomization, etc., is required.  PGAA involves irradiating a sample with a collimated beam of neutrons while concurrently observing production of gamma rays, which, in turn, have energies characteristic of the elements from which they originated.

At the NCNR, collimated neutron beams may be restricted in diameter by means of circular apertures, and this in turn restricts the volume that is probed in a PGAA measurement.  However, reducing the size of the impinging neutron beam results in a reduced production of gamma rays and subsequently longer acquisition times.  Therefore, a spatially resolved measurement using a very thin beam of neutrons is impractical.  However, it has been previously demonstrated that, rather than restricting a beam using apertures, a neutron lens can be used to focus a broad-diameter beam of cold neutrons onto a small spot.  In this case, the measurement can be restricted to a small volume without such a great loss in count rate.  The continuation of an earlier project using a neutron lens to provide mm3-spatial resolution technique will be described.






CATEGORY: Chemistry


Name:  Richard Bindel



Mentors Name:  Elizabeth Mackey

Analytical Chemistry Division, CSTL

Room B169, Building 235, Mail stop 8395

Tel: (301) 975-5149

Fax: (301) 208-9279

Email: richard.bindel@nist.gov


Is your mentor a Sigma Xi Member? No