Capture-Gamma Determination ofV51Levels

Abstract

A fast-coincidence scintillation spectrometer has been developed for thermal-neutron capture-gamma studies at the Livermore 1-Mw pool-type reactor. The added-neutron binding energy in V 51 was measured as 11.1 ±0.1 Mev. Cascade radiations for V 51 * were observed and a decay scheme is established which verifies a previously proposed (p,p') level scheme. Spin assignments for most of the V 51 (p,p f ) reported levels below 4.0 Mev are proposed and the level order for the (I/7/2) 3 proton configuration levels is established as 7/2" (ground state), 5/2", 3/2~, 11/2", 9/2",' and 15/2~ spin with excitation energies of 0.32, 0.93, 1.61, 1.81, and 2.70 Mev, respectively. Of the various nuclear force assumptions that can be made, the short-range force approximation (5-type interaction) and weak surface-coupling effects for V 51 * configuration states appear to give the best match between theory and experiment. A previous calculation using experimentally measured splittings of the j 2 configuration together with tabulated coefficients of fractional parentage gives excellent agreement with experiment. Evidence is also found for (l/V/2 2 )o2^3/2and (l/ 7 /2 2 )ol/5/2-proton single-particle levels at 2.41 and 2.55 Mev, respectively, as well as for additional low-spin states between 2.70 and 3.38 Mev which possibly represent even states resulting from excitation of a lower shell proton to give a (l/V/2 4 )o configuration plus a proton hole in the vacated shell. Experimental results suggest that the V 51 * 20-28 core is a more rigid structure than the Ca 43

Spectroscopy in the Nuclear1f72Shell

“…Rev. 124, 1500(1961 predicted in each scheme are the same, the wave functions strongly overlap. There are several cases, however, in which Lawson's predictions are quite different from the present ones; one of these, Ti 45 , is now being measured 39 and may help to resolve the question of relative success.…”

Thermal neutron capture in50V

“…The latest and most precise value for the total thermal neutron crosssection is reported by Vertebnyi et al [1] as 48+4b. Only one previous study [3] has been reported in which primary capture radiation from an enriched target was observed. Fragmentary information [2] regarding the spectrum of 7 rays following capture has been obtained from the study of radiation produced in a natural vanadium target.…”

Determining Experimental Transition Strengths of 52 V by Two-Step Gamma Cascades

“…The exited states of 52 V have been studied from 60's of the last century. The 52 V level scheme has mainly been performed by means of the 51 V(d, p) 52 V and 51 V(n, ) 52 V reactions [3,4,5,6,9]. The Ritz algorithm was used to construct nuclear level scheme from low energy neutron capture gamma rays.…”