Angular distributions of fast photoneutrons from thirteen elements,

1968 ◽  
Vol 46 (16) ◽  
pp. 1823-1825 ◽  
Author(s):  
J. W. Jury ◽  
J. S. Hewitt ◽  
K. G. McNeill

The angular distribution of fast (> 5 MeV) photoneutrons from V, Cr, Mn, Br, Mo, Ru, Rh, Pa, Sb, La, Pr, Pt, and Pb have been measured at bremsstrahlung energies of about 22 MeV. The results expand and confirm previously noted variations of anisotropy with neutron occupation number, and in particular they confirm the peaking of the anisotropy at the closing of p and d subshells.

1959 ◽  
Vol 37 (12) ◽  
pp. 1418-1437 ◽  
Author(s):  
A. P. Baerg ◽  
R. M. Bartholomew ◽  
F. Brown ◽  
L. Katz ◽  
S. B. Kowalski

Angular distributions of photofission fragments relative to the photon beam have been measured as a function of maximum bremsstrahlung energy in the range 6–20 Mev. The nuclides U-233, U-235, Np-237, Pu-239, and Am-241 give an isotropic distribution at all energies studied. The nuclides Th-232, U-234, U-236, U-238, and Pu-240 give anisotropic distributions which can be described by an equation of the form W(θ) = 1 + α sin2 θ where θ is the angle between fragment and beam. The degree of anisotropy is large at low energy and falls rapidly as the energy is increased. At a given energy Th-232 has the greatest degree of anisotropy and Pu-240 the least.


1967 ◽  
Vol 45 (9) ◽  
pp. 2851-2857
Author(s):  
S. M. Hussain ◽  
K. G. McNeill

Measurements have been made of the angular distributions of fast (E > 5 MeV) photoneutrons from eight elements in the region Z = 28 to Z = 50, and from lead, using threshold detectors. It is found that there is evidence for peaking of the anisotropy of these photoneutrons at the closing of the. N = 56 subshell.


1968 ◽  
Vol 46 (6) ◽  
pp. 753-758 ◽  
Author(s):  
E. Formann ◽  
F. P. Viehböck ◽  
H. Wotke

Based on the hard-sphere potential approximation, angular distributions of scattered particles at different mass ratios M1:M2 were calculated. The results were compared with experiments carried out with the following atoms:[Formula: see text]The sputtered particles from the target as well as from the incident-ion beam were collected on graphite rods and measured by either activation analysis or a radioactive tracer technique.


Recent investigations have shown that the inelastic scattering of electrons in gases exhibits some very interesting phenomena. In previous papas we have described the angular distribution of the scattering of electrons which have lost a discrete amount of energy. Papers I and II described preliminary results which established the existence of diffraction effects at large angles in a number of gases. In Paper III the measurements were carried out over a range of velocities lower than those previously studied, results being obtained for incident electron energies down to within a few volts of the excitation potential. angular distributions were obtained for the inelastic scattering of electrons in hydrogen, helium, and argon between the angles 10° and 155°. The present paper describes the extension of the measurements to methane, nitrogen, neon and mercury vapour.


The methods previously described have been applied to a study of the elastic scattering of 4·2 MeV protons by deuterium, helium, nitrogen, oxygen, neon, argon, chlorine and bromine. The results obtained with deuterium and helium as the scattering gases are compared with those of other experimenters working with protons of different energies. The angular distributions of the protons elastically scattered by nitrogen and oxygen, together with the results for carbon obtained in previous measurements, can be simply described in terms of an S -component interacting with the Coulomb term in the formula for the scattered wave. Values are obtained in each case for the magnitude of the parameter which defines the amplitude and phase of the S -wave. The angular distribution of the protons inelastically scattered by neon has been investigated and evidence obtained for similar collision processes in experiments with argon and chlorine.


1951 ◽  
Vol 4 (3) ◽  
pp. 296
Author(s):  
SL Martin

When nuclear emulsions are used in the investigation of the angular distributions of scattered particles those tracks which pass through the emulsion surface cannot be accepted for measurement and in consequence the observed angular distribution must be corrected to allow for this. In the present paper, formulae are developed for the case of particles recoiling from a mono-energetic beam of particles incident at any angle on the surface. The effect of small-angle scattering is neglected but on the basis of work done by Powell and Occhialini it is believed that the formulae are valid for recoil energies at least as great as 5 MeV. Curves are given from which the factor can be obtained in any given case.


A thin gas target was used and the particles from the reactions were detected by a proportional counter. The results show that the total cross-section for the two reactions is the same to within 1%, but that the angular distributions of the products are significantly different. The asymmetry coefficient for the reaction D( d , n ) 3 He is given by 0·31 + 0·0058 E , compared with 0·13 + 0·0047 E for reaction D( d , p ) 3 H, where E is the bombarding energy in kilovolts.


1966 ◽  
Vol 44 (12) ◽  
pp. 2961-2971 ◽  
Author(s):  
S. K. Mark ◽  
P. M. Portner ◽  
R. B. Moore

Elastic and inelastic scattering of protons on 7Li, 9Be, and 12C have been studied, using the 100-MeV proton beam from the McGill synchrocyclotron. Differential cross sections for the various groups of scattered protons were measured over an angular range of 5° to 90° (lab). For proton groups resulting from a quadrupole excitation in the target nucleus, the angular distribution was found to increase at scattering angles less than 10°. Angular distributions corresponding to an octupole excitation were observed to decrease at small angles. The results have been compared with existing data in this energy region.


Author(s):  
MQ Liu ◽  
JL Mo ◽  
DW Wang ◽  
JX Li ◽  
MH Zhu ◽  
...  

This study experimentally investigated the influence of angular distribution of a grooved surface on wear properties as well as friction-induced vibration and noise characteristics. The surfaces of brake disc material were modified by cutting grooved surfaces with different angular distributions. The differences between the grooved and smooth surfaces in friction and wear and friction-induced vibration and noise were evaluated. This was performed via a pad-on-disc test configuration where the brake pad material was used as a counterface. The test results indicated that all the grooved surfaces with different angular distributions had significant potential in improving friction and wear behaviors of the contact surfaces and also in reducing the amplitudes of high-frequency vibration accelerations and noise pressure levels. Additionally, the results indicated that the ability of the grooved surfaces to suppress the generation of noise is closely related to the angular distribution of the grooves and the interference length of the grooved surfaces on the contact interface. The grooved surface allowed for entrapping and exhausting wear debris from the contact interface, which improved the wear status, and this was one of the reasons for the noise reduction of the grooved surface to a certain extent. Meanwhile, another reason was that the grooved surface interrupted the concentrated contact pressure and changed the contact pressure distribution on the leading edge of the contact surface.


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