TABLE OF ELECTRON WAVE FUNCTIONS AT THE NUCLEAR SURFACE

Abstract

The beta and gamma radiations of 21-hr I/sup 133/ were investigated by single-crystal and multicrystal scintillation spectrometers, and a scheme is proposed for the energy levels of Xe/sup 133/. The level scheme of Ge/sup 74/ was obtained by means of single-crystal and multicrystal beta- and gammaray spectrometry using sources of Ga/sup 74/ and As/sup 74/. The angular correlation for the 0.60-0.60-Mev cascade was measured. Both beta- and gamma-ray single- crystal measurements and gamma-beta and gamma-gamma coincidence experiments were performed on the decay of I/sup 132/. Also, gamma-gamma angular correlations were measured for all the prominent gamma rays. This information has led to a level scheme in Xe/sup 132/ involving excited states at 0.673, signments of 2, 4, 3, and 4 for the first four of these. A study of 2.7-hr Pm/sup 150/ established that the most energetic beta ray, at 3.16 plus or minus 0.11 Mev, decays to the first excited state of Sm/sup 150/ at 0.333 Mev. A partial decay scheme based on beta-gamma coincidence spectrometry was formulated with excited states in Sm/sup 150/ at 0.333, 1.18, 1.66, and 2.08 Mev. The measurement of the neutron- absorption cross sections of Ce/sup 141/ and Ce/sup 144/ by the activation method is in progress. Separation of the 5.9-hr Pr/sup 145/ daughter of the 3-min Ce/ sup 145/ produced by the (n, gamma ) reaction on Ce/sup 144/ from the associated cerium isotopes was accomplished by the extraction of tetravalent cerium with di(2-ethyl-hexyl)phosphoric acid in n-heptane. Preliminary results of several irradiations of Ce/sup 144/ in the LITR indicate an effective neutron cross section of (6 plus or minus 2) x 10/sup -24/ cm/sup 2/atom. Flux depressions in the vicintty of and within infinite cadmium slabs were calculated using the SNG reactor code on the IBM-704 computer at K-25. These results are pertinent to burnout calculations concerning cadmium filters during long irradiations. An upper limit of 0.1 barn was set for the formation cross section of the 25-sec isomer of Po/sup 211/ from Po/sup 210/ for thermal reactor neutrons. An upper limit of about 7 x 10/sup 5/ years was obtained for the haif life of Bi/sup 208/ by measuring the disintegration rate and measuring qualitatively the Bi/sup 208/ Bi/sup 209/ ratio; this value is consistent with an approximate estimate of 7.5 x 10/sup 5/ years by C. H. Miller and co-workers at Chalk River. A value of 870 barns was determined for the fission resonance integral of U/sup 233/ from analyses of three fission products: Sr/sup 89/, Mo/sup 99/, and Ba/sup 140 /. This value may be compared with two values, 900 and 820 barns, calculated from available resonance data. Work on electron depolarization by scattering and the effect of multiple scattering on scattering asymmetry, along with changes in experimental equipment, will allow the use of weaker sources in beta-ray polarization measurements. (auth)