PHYSICS DIVISION PROGRESS REPORT FOR APRIL 1, 1958 TO JUNE 30, 1958

Technical Report · Fri Oct 31 04:00:00 EST 1958

OSTI ID:4305565

Mechanisms for thermonuclear reactions in stars were investigated in an attempt to explain Cf/sup 254/ production. The gamma branching ratio for Rb/sup 86/ was measured as 5.7 plus or minus 0.2%, fission product mass distributions were obtained for U/sup 236/. Energy levels, spins, and parities are tabulated for O/sup 18/. Energies and intensities were measured for four gamma rays from the reaction Mg/sup 26/ ( alpha ,n gamma ) Si/sup 29/. Excitation energies and excitation cross section ratios are tabulated for F/sup 18/, Na/sup 23/, Ti/sup 47/, and Mn/sup 5 excitation by He/sup 3/ and He/sup 4/. Calculations of gamma transition probabilities were carried out for excited levels in F/sup 18/. Neutron detectors were evaluated for their applicability to (p,n) threshold experimentation in tandem accelerators. Initial tests on the Chalk River tandem Vande Graaff accelerator are described. Gamma energies, spins, and parities were determined for levels in B/sup 11/ resulting from the reaction Li/sup 7/( alpha , gamma ) An unusually abrupt decrease in cosmic radiation occurred on February 11, 1958. The variation as detected by three counter; is tabulated. Neutron spectrometer and spectrometer data recording equipment developments are reviewed. Gamma energies are tabulated for (n, gamma ) reactions in Gd/sup 157/, Te/sup 123/ , Ti, Mg/sup 25/, S/sup 3 and P/sup 32/. Pressure effects cn neutron scattering in liquid He were measured between 3.7 and 21.4 atmospheres. The new NRX control system was completely tested and put into regular use. Basic studies of transistor pulse amplifiers were continued. The convergence of the spherical harmonics approximation to the extrapolated end-point, Z/sub 0/, and the current- to-flux ration, j(o)/e(o), in the Milne problem was examined. The results are given from neutron resonance absorption studies of an NRX natural U rod. Work was continued on the development of the mathematics for describing neutron spectra in the vicinity of absorbing slabs. The many-level formula was used in examining neutron resonances in Pu/sup 239/. The model of a nucleus obtained using a cut-off oscillator potential as asingle particle single potential was improved by introducing separate potentials for neutrons and protons. (For preceding period see PR-P-37.) (D.E.B.)

• Research Organization: Atomic Energy of Canada Ltd. Chalk River Project, Chalk River, Ont.
• NSA Number: NSA-12-016634
• OSTI ID: 4305565
• Report Number(s): PR-P-38; AECL-673
• Country of Publication: Canada
• Language: English

Related Subjects

ABSORPTION-- FUEL ELEMENTS-- NRX-- REACTORS-- RESONANCE NEUTRONS-- RODS-- URANIUM
ABSORPTION-- MATHEMATICS-- NEUTRONS-- NUMERICALS-- RODS-- SPECTRA
ALPHA BEAMS-- BEAMS-- CROSS SECTIONS-- ENERGY-- EXCITATION-- FLUORINE 19-- MANGANESE 55- - SODIUM 23-- TABLES-- TRITONS
ALPHA BEAMS-- BORON 11-- ENERGY LEVELS-- GAMMA RADIATION-- LITHIUM 7-- NUCLEAR REACTIONS-- PARITY-- SPIN
ALPHA BEAMS-- ENERGY LEVELS-- GAMMA RADIATION-- MAGNESIUM 26-- NEUTRONS-- NUCLEAR REACTIONS-- SILICON 29
AMPLIFIERS-- PLANNING-- PULSES-- TRANSISTORS
ASTROPHYSICS-- CALIFORNIUM 254-- PRODUCTION-- STARS-- THERMONUCLEAR REACTIONS
CONTROL SYSTEMS-- NRX-- REACTORS-- TESTING
PHYSICS