International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

International Tables for Crystallography (2006). Vol. C, ch. 4.4, p. 461

Section 4.4.6. Absorption coefficients for neutrons

B. T. M. Willish

4.4.6. Absorption coefficients for neutrons

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The cross sections σ discussed in Section 4.4.4 represent the area of each nucleus as seen by the neutron. To calculate the beam attenuation arising from absorption it is more convenient to use the macroscopic cross section , which is the cross section per unit volume in units of cm−1. is derived by multiplying σ for the element by the number of atoms per unit volume. Thus, for element j, with density and atomic weight , where is Avogadro's number.

Table 4.4.6.1 gives the macroscopic absorption cross sections of the elements. They are tabulated for a neutron velocity v = 2200 m s−1, corresponding to a wavelength of 1.80 Å. The cross sections are larger at longer wavelengths (Section 4.4.4). Apart from a few exceptions, such as boron and cadmium, the absorption cross section is vastly smaller than for X-rays. The 1/e penetration depth (l) is listed separately – most metals, for example, have a penetration depth of several cm. The data in Table 4.4.6.1 have been derived from the review article by Hutchings & Windsor (1987).

 Table 4.4.6.1| top | pdf | Absorption of the elements for neutrons (λ = 1.80 Å)
AtomΣa (cm−1)l (cm)
H 0.0141 0.288
D 0.0000 6.17
He 0.0001 20.22
Li 3.2698 0.300
Be 0.0009 1.059
B 105.41 0.009
C 0.0004 1.58
N 0.0662 2.14
O 0.0001 5.52
F 0.0003 6.82
Ne 0.0017 8.71
Na 0.0135 10.22
Mg 0.0027 6.11
Al 0.0139 9.48
Si 0.0085 8.45
P 0.0061 8.04
S 0.0208 16.14
Cl 0.9109 0.731
Ar 0.0143 2.03
K 0.0279 18.12
Ca 0.0099 12.35
Sc 1.0906 0.491
Ti 0.3453 1.74
V 0.3658 1.35
Cr 0.2558 1.82
Mn 1.0900 0.789
Fe 0.2174 0.82
Co 3.3440 0.260
Ni 0.4104 0.475
Cu 0.3202 1.00
Zn 0.0730 2.89
Ga 0.1480 2.04
Ge 0.1016 2.07
As 0.2091 2.15
Se 0.4292 1.36
Br 0.1623 3.31
Kr 0.3882 1.97
Rb 0.0041 13.09
Sr 0.0227 7.44
Y 0.0388 3.66
Zr 0.0079 3.42
Nb 0.0640 2.42
Mo 0.1637 1.75
Tc 1.4281 0.542
Ru 0.1886 1.48
Rh 10.544 0.092
Pd 0.4687 1.29
Ag 3.7120 0.249
Cd 116.80 0.008
In 7.4135 0.133
Sn 0.0231 4.87
Sb 0.1689 3.20
Te 0.1386 4.01
I 0.1458 4.36
Xe 0.3904 2.27
Cs 0.2458 3.57
Ba 0.0189 13.39
La 0.2402 2.00
Ce 0.0182 9.60
Pr 0.3333 2.46
Nd 1.4763 0.496
Sm 171.23 0.005
Eu 95.715 0.010
Gd 1474.1 0.000
Tb 0.7334 1.05
Dy 29.731 0.030
Ho 2.0791 0.424
Er 5.1861 0.182
Tm 3.4919 0.269
Yb 0.8513 0.717
Lu 2.5889 0.354
Hf 4.6648 0.195
Ta 1.1434 0.676
W 1.1609 0.681
Re 6.1692 0.143
Os 1.1444 0.442
Ir 30.064 0.032
Pt 0.6843 0.682
Au 5.8181 0.159
Hg 15.146 0.061
Tl 0.1200 2.15
Pb 0.0056 2.68
Bi 0.0009 3.84
Ra 0.1706 2.95
Th 0.2244 1.68
Pa 8.0405 0.118
U 0.3650 1.26
Np 9.0534 0.10
Pu 14.481 0.069
Am 2.5522 0.351

References

Hutchings, M. T. & Windsor, C. G. (1987). Industrial applications of neutron scattering. In Methods of experimental physics, Vol. 23, Part C, edited by K. Sköld & D. L Price. New York: Academic Press.