nucreonics DATA SHEET no. 23 
Thermal-Neutron Data For the Elements 
By M. V. DAVIS and D. T. HAUSER 
Hanford Laboratories Operation 
General Electric Company 
Richland, Washington 
The widespread acceptance of an 
earlier thermal-neutron-data tabula- 
tion by Kroeger (1) has stimulated this 
updated compilation. Intended pri- 
marily for calculations related to reac- 
tor studies, it should also prove useful 
in neutron-source and shielding studies. 
The material, for the most part, is 
found in the references or calculated 
using standard techniques, such as are 
presented by Glasstone and Edlund (2). 
The cross sections are the 2,200-m/sec 
cross sections. Non-1/v cross sections 
are corrected to yield a result equiva- 
lent to a 1/v cross section in a Max- 
wellian thermal-neutron flux. 
The average value for the cosine of 
the scattering angle, fio, is calculated 
from fio = 2/3A, where A is the mass 
of the scattering nucleus. 
The average logarithmic energy 
decrement, ~, is found from the ap- 
proximation = 2/(A + 34) for the 
elements with mass larger than 10. 
For the lighter elements, § = 1+ 
((A — 1)?/2A4]fln (A — 1)/(A + 1). 
The diffusion coefficient is D = L?Z, 
or D = ),/3(1 — fo), where A,/(1 — fo) 
is the transport mean free path. The 
transport cross sections and mean free 
path were deleted to allow space for the 
resonance integral, the moderation area 
and the diffusion coefficient. 
The cross sections given in the table 
are the absorption (a), scattering (s) 
and total (t) cross sections. 
* s * 
This work was performeu under the auspices 
of the U. S. Atomic Energy Commission. 
BIBLIOGRAPHY 
1. H. R. Kroeger, Nucteontcs &, No. 4, 51 (1949) 
#. 8. Glasstone, M. C. Edlund, ‘‘ The Elements of 
Nuclear Reactor Theory’’ (D. Van Nostrand, 
Princeton, 1952) 
. D. J. Hughes, J. A. Harvey, Neutron Cross 
Sections, BNL-325 (1955) 
. J. F. Stehn, E. F. Clancy, General Electric 
Chart of the Nuclides, 5th ed. (1956) 
“The Reactor Handbook, Vol. 1, Physics,” 
AECD-3645 (1955) 
. R. L. Macklin, H. 8. Pomerance, Resonance 
Capture Integrals, in “‘Progress in Nuclear 
Energy,” vol. 1 (McGraw-Hill Book Co., New 
York, 1956) 
. E. Critoph, CRRP-655 AECL No. 350 (1956) 
. H. Neumann. Effective scattering masses for 
mixtures, HW-48814 (1957) 
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* Atonle ne. i- 
Neutron Data 
w= X 108 /x = X 10-5 
{ Activation integral $ Measured 
* Molecules/cm? 
233 
