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Nuclear Data Sheets for A = 139

The experimental nuclear spectroscopic data for known nuclides of mass number 139 (Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy) have been evaluated and presented together with adopted properties for levels and gamma rays. This evaluation represents a revision of previous one (2001Bu16) by T.W. Burrows. Since then extensive new data have become available for many A=139 nuclides although, no excited state data are yet available for {sup 139}Sn, {sup 139}Sb, {sup 139}Tb, and {sup 139}Dy. The decay schemes of {sup 139}Sn, {sup 139}Sb, {sup 139}I, {sup 139}Tb and {sup 139}Dy nuclei are not known, and those for {sup 139}Gd and {sup 139}Eu are poorly known. Particle-transfer data are available for {sup 139}Ba, {sup 139}La, {sup 139}Ce and {sup 139}Pr. Limited high-spin data are available for {sup 139}Te, {sup 139}I, {sup 139}Cs, {sup 139}Ba, {sup 139}La and {sup 139}Ce, while such data are extensive for {sup 139}Pr, {sup 139}Nd, {sup 139}Pm, {sup 139}Sm, {sup 139}Eu and {sup 139}Gd. Recent {sup 139}Pm high-spin data from two independent studies using the same reaction and similar beam energy are in conflict and could be improved using state-of-the-art large gamma-detector arrays in contrast to the smaller arrays currently used. Cases for which no new experimental information are available since the last update have undergone checking resulting in some changes in the current work, but for the most part these are taken from the previous evaluations. Thus, the present work has greatly benefited from all prior NDS evaluations (2001Bu16, 1989Bu12, 1981Pe04, 1974Gr46), but at the same time data presented herein supersede those in the earlier evaluations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Reactor production of promethium-147

In this paper, we describe the 147 Pm production yields and level of impurities from several targets that consisted of milligram quantities of highly enriched 146 Nd oxide irradiated at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory for durations ranging from 24 to180 h. A comparison between theoretical and experimental data are also presented, and attempts were made to empirically evaluate the neutron capture cross-sections of 41.3-d 148m Pm and 5.4-d 148g Pm. For a one-cycle irradiation (~24 days), 147 Pm yield reaches a maximum value of 101.8 MBq/mg (2.75 mCi/mg) at 60 days after the end of bombardment. Because of large neutron capture cross-sections of 147 Pm, the yield of 147 Pm does not significantly increase with longer irradiation. Our estimates of the thermal neutron capture cross-section and resonance integral for 146 Nd at 1.48 ± 0.05 b and 2.56 ± 0.25 b, respectively, were consistent with the reported values. The effective neutron capture cross-section of 147 Pm to 148m Pm was 53.3 ± 2.7 b - a factor of 2 lower than the 98.7 ± 6.5 b calculated from reported cross-sections. The measured σ eff to the ground state (5.37-d 148g Pm) was 82.0 ± 4.1 b; ~34 % lower than the value of 139 ± 0 b calculated from reported cross-sections. In this work, we also describe the development of a chemical process based on extraction and ion-exchange chromatography for separation of 147 Pm from milligram quantities of 146 Nd and other impurities. Sequential separation of Pm from the Nd target and from other radioisotopic impurities ( 153 Gd and 154&155 Eu, 192 Ir, and 60 Co) was achieved using a LN extraction resin in HCl media followed by further purification of Pm from 60 Co and 192 Ir using a low cross-linking cation exchange resin. Based on these data, we estimated that two rounds of purification under our experimental conditions can provide a mass separation factor of > 104 between Pm and Nd. Our data indicate that curie quantities of 147 Pm with suitable chemical and radioisotopic purity for applications in beta voltaic batteries can be produced by irradiating gram quantities of highly enriched 146 Nd in the flux trap of HFIR for one cycle.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗