PMID- 1466451
OWN - NLM
STAT- MEDLINE
DCOM- 19930119
LR  - 20190717
IS  - 0003-2700 (Print)
IS  - 0003-2700 (Linking)
VI  - 64
IP  - 20
DP  - 1992 Oct 15
TI  - Use of spherical targets to minimize effects of neutron scattering by hydrogen in 
      neutron capture prompt gamma-ray activation analysis.
PG  - 2366-71
AB  - For hydrogenous targets that are thinner than they are wide, element 
      sensitivities (counts.s-1.mg-1) for determining concentrations of elements by 
      neutron capture prompt gamma-ray activation analysis (PGAA) are enhanced relative 
      to sensitivities obtained from measurements on nonhydrogenous materials. These 
      enhancements are caused mainly by elastic neutron scattering by H, which changes 
      the average neutron fluence rate within the matrix. The magnitude of the effect 
      depends on the macroscopic scattering and absorption cross sections and on the 
      size, shape, and orientation of the target with respect to the neutron beam. 
      Sensitivities increase linearly with H density for thin targets of constant size 
      and shape and also vary with target shape. Theoretical work was shown that 
      element sensitivities for hydrogenous targets in the form of spheres are least 
      affected by neutron scattering. Methods were devised for creating solid spheres 
      and for containing liquids in spherical shapes. Element sensitivities were 
      determined for spheres and disks of several hydrogenous materials. For H, B, Cl, 
      K, Br, and Cd, sensitivities for spheres were found to be less affected by 
      neutron scattering. Exceptions were Sm and Gd sensitivities measured in liquids 
      contained in quartz globes.
FAU - Mackey, E A
AU  - Mackey EA
AD  - Department of Chemistry and Biochemistry, University of Maryland, College Park 
      20742.
FAU - Gordon, G E
AU  - Gordon GE
FAU - Lindstrom, R M
AU  - Lindstrom RM
FAU - Anderson, D L
AU  - Anderson DL
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - Anal Chem
JT  - Analytical chemistry
JID - 0370536
RN  - 7YNJ3PO35Z (Hydrogen)
SB  - IM
MH  - Chemistry Techniques, Analytical/*methods
MH  - Gamma Rays
MH  - Hydrogen
MH  - Neutron Activation Analysis/*methods
MH  - Neutrons
MH  - *Scattering, Radiation
EDAT- 1992/10/15 00:00
MHDA- 1992/10/15 00:01
CRDT- 1992/10/15 00:00
PHST- 1992/10/15 00:00 [pubmed]
PHST- 1992/10/15 00:01 [medline]
PHST- 1992/10/15 00:00 [entrez]
AID - 10.1021/ac00044a012 [doi]
PST - ppublish
SO  - Anal Chem. 1992 Oct 15;64(20):2366-71. doi: 10.1021/ac00044a012.