Neutron slow--------scattering

If one wanted to predict slow neutron incoherent scattering from CO then, in the Gaussian approximation, all one would need would be the... 

Boutin, H., H. Prask, S. F. Trevino, and H. Danner Study of the low-frequency molecular motions in polyethylene and the -paraffins by slow neutron inelastic scattering. Proceedings of Symposium on Inelastic Scattering of Neutrons, Bombay, Dec. 1964, Vol II, 407—419 pp. I. A. E. A., Vienna, 1965. 

Nexkin, M. Slow-neutron inelastic scattering and neutron thermalization. 

DIFFUSIVE MOTIONS IN BENZENE AND TOLUENE STUDIED WITH SLOW NEUTRONS. FROM PROCEEDINGS OF A SYMPOSIUM ON NEUTRON INELASTIC SCATTERING HELD BY THE INTERNATIONAL ATOMIC ENERGY AGENCY IN COPENHAGEN,... 

The multiplication factors were calculated using the 16-group cross sections of Hansen and Roach for uranium and carbon and the KENO code which is a multigroup Monte Carlo method with isotropic scattering and with neutron slowing down treated by a transfer matrix. Twenty-one thousand neutron histories (105 batches of 200 source neutrons each) were calculated requiring a time of 20 min on the IBM 360-75 for each proUem. The source neutrons were put in the uranium uniformly and the first five batches were discarded. 

The last equality follows from the fact that no neutrons can be lost in a medium of pure scattering material, and the number of neutrons slowing... 

A typical history of a neutron slowing down in a medium which contains both absorbing and scattering materials was described in Sec. 2.1a. An important feature of this process was that at every collision between a neutron and a nucleus there was a finite probability that the neutron could be absorbed. The probability that a neutron is absorbed upon making a collision is 2o(iJ)/2t( ), and that it be scattered,... 

Neutron slowing down is due only to elastic-scattering > (7.106)... 

Answer The thermal shield acts as a filter which strains out the thermal neutrons and most of the pile gammas, and so prevents overheating of the biological shield. The thermal shield scatters fast neutrons, slowing them down considerably, but most of the fast and Intermediate neutrons are not conqpletely slowed down and captured until they enter the biological shield. 

The Q and ft) dependence of neutron scattering structure factors contains infonnation on the geometry, amplitudes, and time scales of all the motions in which the scatterers participate that are resolved by the instrument. Motions that are slow relative to the time scale of the measurement give rise to a 8-function elastic peak at ft) = 0, whereas diffusive motions lead to quasielastic broadening of the central peak and vibrational motions attenuate the intensity of the spectrum. It is useful to express the structure factors in a form that permits the contributions from vibrational and diffusive motions to be isolated. Assuming that vibrational and diffusive motions are decoupled, we can write the measured structure factor as... 

Silylated diamines, 156, 187-188 Silylated monomers, 72 Silylation, distillation and, 338 6NT6 alternating polyesteramide, synthesizing, 189-190 6,6 -linked polymers, 480 Size exclusion chromatography (SEC) analyses, 90, 490 Slabstock foam, 233-234 Slow monomer addition, 57 Small-angle neutron scattering (SANS), 282... 

As indicated, the power law approximations to the fS-correlator described above are only valid asymptotically for a —> 0, but corrections to these predictions have been worked out.102,103 More important, however, is the assumption of the idealized MCT that density fluctuations are the only slow variables. This assumption breaks down close to Tc. The MCT has been augmented by coupling to mass currents, which are sometimes termed inclusion of hopping processes, but the extension of the theory to temperatures below Tc or even down to Tg has not yet been successful.101 Also, the theory is often not applied to experimental density fluctuations directly (observed by neutron scattering) but instead to dielectric relaxation or to NMR experiments. These latter techniques probe reorientational motion of anisotropic molecules, whereas the MCT equation describes a scalar quantity. Using MCT results to compare with dielectric or NMR experiments thus forces one to assume a direct coupling of orientational correlations with density fluctuations exists. The different orientational correlation functions and the question to what extent they directly couple to the density fluctuations have been considered in extensions to the standard MCT picture.104-108... 

The application of neutron spin-echo spectroscopy to the analysis of the slow dynamics of biomolecules is still in its infancy, but developing fast. The few published investigations either pertain to the diffusion of globular proteins in solution [332-334] or focus on the internal subnanosecond dynamics on the length scale, <10 A as measured on wet powders [335,336]. The latter regime overlaps with other quasi-elastic neutron scattering methods as backscattering and TOE spectrometry [337-339]. 

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