RARE NUCLEAR REACTIONS INDUCED BY 14.8 Mev NEUTRONS (thesis)
8 = 8 9 9 < 7 > 8 7 .8 plus or minus 0.8 Mev were measured for STA(n,n alpha ) + (n, alpha n)! reactions on the isotopes Cu/ sup 65/, Zn/sup 70/, Ga/sup 71/, and Nb/sub 93/ while maximum crosssection limits for this reaction were determined for V/sup 51/ In/sup 115/, Au/sup 197/, and Tl/ sup 203/. Crosssection limits also were established for (n,2p) reactions on Si/ sup 29/, K/sup 41/, Sc/sup 45/, Ti/sup 50/, V/sup 51/, Mn/sup 55/, As/su p 75/, Y/ sup 89/, Nb/sup 93/, Cs/sup 133/, 9/; and for (n,He/sup 3) reactions on K/sup 41/ , Sc/sup 45/, V/sup 51/, Mn/sup 55, Co/sup 59/, Cu/sup 63/, As/sup 75/, Nb/sup 9 3/, Rh/sup 103/, Cs/sup 133/, Au/sup 197/, and Tl/sup 205/. Cross-section values for (n, gamma ) reactions on Y/sup 89/, ctions on Pr/sup 141/, Au/sup 197/, and Tl/sup 203/ were determined. The STA(n,np) + (n,pn)! reaction was detected with Ni/sup 58/ but not with Mo/sup 92/. A cross-section value was established for the former and a maximum limit for the latter. Absolute disintegration rates required for these determinations were obtained by employing beta and gamma counting methods, while monitor reactions served to eliminate neutron flux measurements. Extensive use was made of radiochemical separations in order to isolate the low-yield, rare-reaction products. Cross sections for (n,p), (n, alpha ) and (n,2n) reactions were investigated. Theoretical cross sections determined for (n, alpha n) reactions were found to agree with the experimentally determined STA(n,n alpha ) + (n, alpha n)! cross sections, thereby suggesting that the path for this reaction sum is predominamtly an (n, alpha n) process. The corresponding experimental (n, alpha gamma ) cross sections were predicted within a factor of two. The Statistical Theory predicts (n,2p) cross sections to be significant for certain low-Z nuclides, e.g., Cr/sup 50/, Ni/sup 58/, Kr/sup 78/, and Mo/sup 92/. N one of these particular nuclides is susceptible to investigation by activation methods. Generally, the theoretical estimates for (n,2n) cross sections were in agreement with the experimental cross sections. Both (n, alpha gamma ) and (n,p gamma ) theoretical estimntes were much lower than experimental for the higher-A nuclides studied; however, this difference is less for lower-A nuclides. The theoretical (n, alpha gamma ) cross sections agree with experiment more often than do the (n,p gamma ) cross sections. (auth) O H2243 Experimental results for the Y/sup 89/(n,n' gamma ) reaction are summarized, including the primary gamma -ray decay modes for eight low-lying states of Y/sup 89/. The significance of the 3/2and 5/2-spin assignments for the 1.51- and 1.75-Mev levels of Y/sup 89/ is discussed. Angular distribution measurements for (n,n' gamma ) radiations from Sr/sup 88/, Y/sup 89/, and Ce/sup 140/ are in progress polarization measurements were made for the scattering of 3.3-Mev neutrons from Ca, Zn, Se, Sr, Y, Ag, In, and Sb. Experimental studies relating to (p,n gamma ) reactions included the measurement of a thin-target excitation curve of 393-kev radiation arising from the Sr/sup 88/(p,n gamma )Y/ sup 88/ reaction, which followed a ( DELTA E)/sup 3/2/ law near threshold. Studies of radioactivities produced by (p,n) reactions yielded improved gamma energies for some of the prominent gamma rays from 78-hr Zr/sup 89/ (908 plus or minus 3, 1703 plus or minus 9 kev) and 4.2-min Zr/sp 89m/ (1506 plus or minus 5 kev) and an improved va1ue for the half life of Zr/sup 89/ (preliminary value: 78.4 plus or minus 0.1 hr). An experimental study of gamma-gamma angular correlations perturbed by the hyperfine interaction was initiated, with the objective of investigating nuclear moments of excited states. In this connection, a theoretical investigation of a correlation perturbed by a static anisotropic hyperfine interaction was undertaken. One feature of the theoretical results was that under certain conditions, an angular correlation resonance experiment'' is possible, in which the coincidence counting rate, for fixed positions of the detectors, exhibits sharp interference peaks as a function of the magnetic
- Research Organization:
- Arkansas. Univ., Fayetteville
- NSA Number:
- NSA-17-002242
- OSTI ID:
- 4770919
- Report Number(s):
- TID-16949
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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RARE NUCLEAR REACTIONS INDUCED BY 14.7-Mev NEUTRONS
(n,2n), (n,p), AND (n,/cap alpha/ EXCITATION FUNCTIONS OF SEVERAL NUCLEI FROM 7.0 TO 19.8 MEV
Related Subjects
ACTIVATION
ALPHA PARTICLES
ARSENIC 75
BROMINE 81
CESIUM 133
CHROMIUM 50
COBALT 59
COPPER 63
COPPER 65
CROSS SECTIONS
ENERGY RANGE
GALLIUM 71
GAMMA RADIATION
GERMANIUM 76
GOLD 197
HELIUM 3
INDIUM 115
KRYPTON 78
LANTHANUM 139
MANGANESE 55
MEASURED VALUES
MEV RANGE
MOLYBDENUM 92
NEUTRON BEAMS
NEUTRONS
NICKEL 58
NIOBIUM 93
NUCLEAR REACTIONS
NUMERICALS
POTASSIUM 41
PRASEODYMIUM 141
PROTONS
RADIOCHEMISTRY
RHODIUM 103
RUBIDIUM 87
SCANDIUM 45
SEPARATION PROCESSES
SILICON 29
SILVER 107
SILVER 109
STATISTICS
TERBIUM 159
THALLIUM 203
THALLIUM 205
TITANIUM 50
VANADIUM 51
YTTRIUM 89
ZINC 70