90-Mev Neutron-Proton Scattering at Large Proton Angles

TLDR: Hadley et al. as mentioned in this paper measured the scattering cross section for neutrons for center of mass angles from 36° to 180° and showed that the cross section curve does not lie on a curve that is symmetrical about 90°.

Abstract: 90 Mev Neutron ... Proton Scattering B:t Large Proton Angles, Roger Wallace Radiation ,Laboratory, Department of Physics University of California, Berkeley, California September 5, 1950 Neutron-proton scattering with 90 Mev neutrons has been investigated by . 1 2 others, ' using a proportional counter technique and also using a cloud chamber. They measUred the scattering cross section for neutrons for center of mass angles from 36° to 180°. The present experiment was an attempt to . 1 . overlap the data of Hadley, et al. from 74° to 36° and to extend the cross section measurements to smaller angles. This experiment was performed with nuclear emulsions in order to permit the detection of protons down to about 1. 5 Mev, and to avoid systematic errors that might be present in the case of other methods of detection. The results agree with those of Hadley, et al., within the probable error, and the cross section curve exhibits beyond 36° the sanie_general trend as the curve measured by Hadley, et al. The measurements con:fir.m .. the fact that there is probably not complete symmetr;v,,o~ .~he n-p cross section curve about 90° in the center of mass system. 1 J .• Hadley, E. L. Kelly, C. E. Leith, E. Segr~, C. Wiegand, and H. York, Experiments on N-P Scattering with 90 and 40 Mev Neutrons, Phys~ Rev. 12, 351 (1949) \\ 2 K. Brueckner; W. Hartsough, E. Hayward and W. Powell, Neutron-Proton ·scattering at 90 Mev, Phys. Rev. 22; 555 (1949) :• ·' UCRL-869 Unclassified Distribution Page 4 90 Mev Neutron-Proton Scattering at Large Proton Angles Roger Wallace Radiation Laboratory, Depa~tment of Physics University of California; Berkeley, California September 5, 1950 ° Introduction Neutron-proton scattering cross sect}ons have been measured using the 90 : ' . . . ,· . · Mev neutrons from the 184-inch Berkeley cyclotron by several different 1 investigators. Hadley,· et aL, used two different arrangements of proportional counters. Their results· are shown in Figure 8. It is seen that their points do not lie on a curve that is symmetrical about 90°. This experiment was performed to find out if the cross section does rise in the small angle region. It has been felt by some that the cross section curve (Figure 8) was flat to the left of 70° and did not rise. The results of this experiment serve to confirm-the rising slope of the curve i? the small angle range, in agree2 ment with Hadley, et al. B~uecker, et al., using a cloud chamber technique, have observed an angular dependence of the n-p cross section similar to that observed by Hadley, et al. The results of the present experiment also agree well with the cloud chamber data. Apparatus and Procedure The main part of the apparatus consisted of ·a nuclear plate camera, similar in design to that used by Panofsky and Fillmore.3 The camera and associated shielding (Figure 1) were mounted on a support, aligned in the 90 Mev neutron beam of the :L84:=inch.cyclotron, similar to the paraffin 'l -' W. K. H. Panofsky and F. L. Fillmore·, The Scattering of Protons by Protons near 30 M~v, Phys. Rev. 7.2,, 57 (1950)

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Full text

Lawrence Berkeley National Laboratory
Recent Work
Title
MeV NEUTRON-PROTON SCATTERING AT LARGE PROTON ANGLES
Permalink
https://escholarship.org/uc/item/36029248
Author
Wallace, Roger Wayne.
Publication Date
1952-11-06
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UNIVERSITY
OF
CALIFORNIA
R,adiation
Laboratory
Contract
No.
W
-7405-eng-48
UCRL-869
Rev.
90
MEV
NEUTRON
-PROTON
SCATTERING
..
AT
LARGE
PROTON
ANGLES
'
Roger
Wayne
Wallace
(Thesis)
November
6,
1952
Berkeley,
California

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TABLE
OF
CONTENTS
I
Introduction
II
Apparatus
and
Procedure
III
Recording
of
Data
IV
Treatment
of
Data
V
Conclusions
Ta.ble
I
References
Figure
Captions
Figures
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