Neutron Scattering

led remotely. It is rauch more convenient to turn on the source when needed by replacing y-
radiation by bremsstrahlung generated by electron bombardment of a heavy metal target .
Using e.g . 35 MeV electrons, we obtain a yield of about 10 -2 n/e resp . 0.8 x 10 14 n/s per mA .
Neutron induced nuclearfission (thé nuclear reacior)
Of all neutron sources realized up to now, nuclear reactors are still thé most intense ones .
We had therefore dedicated a detailed chapter for this kind of source (chapter 1.3) .
For comparison we have compiled thé yields, heat deposition, source strengths and power
densities ofthé varions reactions in thé following Table 1.A .1 .
Reaction Yield Heat deposition Source strength Source power
[MeV / n] [n/s] Density
/ Liter
Spontaneous fission 252Cf 3 .75 n/fission 100 2 x 1012 9-1 0.9
39 W/
9Be (d,n) (15 meV) 1 .2 x 10-2 n/d 1200 8 x 1013 mA-1 -
3H (d,n) (0 .2 MeV) 8 x 10-5 n/d 2500 5 x 101 ' mA"' -
Spallation 28 n/p 20 10 18 0.5 (ESS)
1.33 GeV protons on Hg
Photoproduction 1 .7 x 10 -2 n/e 2000 4 x 10 14 5 (Harwell)
W e,n 35 MeV
235U frssion 1 n/fission 200 2 x 1018 1 .2*
nuclear chain reaction
(HFRGrenoble
* At thé hot spot 3 .3 MW/L. For 2 x 10 18 source neutrons per second this gives a thermal flux of 10' 5 n cm2 s
Table I.A.1
Yield, heat déposition, source strength andpower densityfor selected neutron
sources
Literature
[1] S. Glasstone, A. Sesonske, Nuclear Reactor Engineering ; van Nostrand Comp . Inc ., 1963
[2] K.H . Beckurts, K.Wirtz, Neutron Physics ; Springer-Verlag, 1964
[3] G. Bauer, H. Conrad, K. Friedrich, G. Milleret,H. Spitzer; Proceedings 5 11' International
Con£ on Advanced Neutron Sources, Jül-Conf-45, ISSN 0344-5789, 1981
[4] S. Cierjacks, Neutron Sources for Basic Physics and Applications ; Pergamon Press, 1983
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