Two New Promethium Isotopes; Cross Sections of Some Samarium Isotopes for 14.8-Mev Neutrons

Wille, R.; Fink, R.W.

doi:10.1103/physrev.112.1950

Cited by 36 publications

(2 citation statements)

References 10 publications

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“…Therefore, we have investigated the/?--decay of 152pm and have found [17] three isomers with half-lives of 4.2+0.2rain, 7.5+0.2min and 15.0+ 1.0min. Previous studies [18][19][20][21][22][23][24] on the decay of ~SZPm have reported only half-lives and a few ~,-rays, but discrepancies even existed in the half-lives. In the course of our investigations Daniels and Hoffman [25] have independently discovered three isomers of 152pm and have investigated their decay in some detail.…”

Section: Introductionmentioning

confidence: 89%

Decay of the 4.2-min152Pm into levels of152Sm

et al. 1975

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Abstract. After bombardments of enriched 152Sm with 14-MeV neutrons, three isomers of ~ s 2 Pm, produced by the (n, p) reaction, have been observed with half-lives of 4.2 _+ 0.2 min, 7.5+0.2min and 15.0+ 1.0 rain. Sources of pure 4.2-rain ~S2pm were obtained by separating the promethium from its parent ll-min 152Nd produced by thermal-neutron induced fission of 235U. The beta and gamma radiations of the 4.2-min 152pm have been investigated using semiconductor and scintillation spectrometers. Most of the y-ray transitions could be placed in a level scheme for ~SZSm. Especially interesting is a level at 1 083 keV for which the assignment U =0 + is proposed. In a 4g/~ 7 experiment, the ground state feeding of 152Sm in the /~--decay of the 4.2-rain ~52Pm has been measured to be 61 o/o of all/%ray transitions. A Q/j-value of 3.4 + 0.2 MeV has been obtained.

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Section: Introductionmentioning

confidence: 89%

Decay of the 4.2-min152Pm into levels of152Sm

et al. 1975

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“…152 Pm was discovered by Wille and Fink in the 1958 paper "Two new promethium isotopes; cross sections of some samarium isotopes for 14.8-MeV neutrons" [178]. Enriched 152 Sm 2 O 3 was bombarded with 14.8-MeV neutrons produced in the reaction 3 H(d,n) 4 He from the Arkansas Cockroft-Walton accelerator.…”

Section: Pmmentioning

confidence: 99%

Discovery of cesium, lanthanum, praseodymium and promethium isotopes

May

Thoennessen

2012

Atomic Data and Nuclear Data Tables

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Currently, forty-one cesium, thirty-five lanthanum, thirty-two praseodymium, and thirty-one promethium, isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.summarizing the discovery of isotopes, beginning with the cerium isotopes in 2009 [1]. Guidelines for assigning credit for discovery are (1) clear identification, either through decay-curves and relationships to other known isotopes, particle or γ-ray spectra, or unique mass and Z-identification, and (2) publication of the discovery in a refereed journal. The authors and year of the first publication, the laboratory where the isotopes were produced as well as the production and identification methods are discussed. When appropriate, references to conference proceedings, internal reports, and theses are included. When a discovery includes a half-life measurement the measured value is compared to the currently adopted value taken from the NUBASE evaluation [2] which is based on the ENSDF database [3]. In cases where the reported half-life differed significantly from the adopted half-life (up to approximately a factor of two), we searched the subsequent literature for indications that the measurement was erroneous. If that was not the case we credited the authors with the discovery in spite of the inaccurate half-life. All reported half-lives inconsistent with the presently adopted half-life for the ground state were compared to isomers half-lives and accepted as discoveries if appropriate following the criterium described above. If the first observation of an isotope corresponded to an isomeric state, the first observation of the ground state is also included.The first criterium excludes measurements of half-lives of a given element without mass identification. This affects mostly isotopes first observed in fission where decay curves of chemically separated elements were measured without the capability to determine their mass. Also the four-parameter measurements (see, for example, Ref.[4]) were, in general, not considered because the mass identification was only ±1 mass unit.The second criterium affects especially the isotopes studied within the Manhattan Project. Although an overview of the results was published in 1946 [5], most of the papers were only published in the Plutonium Project Records of the Manhattan Project Technical Series, Vol. 9A, "Radiochemistry and the Fission Products," in three books by Wiley in 1951 [6]. We considered this first unclassified publication to be equivalent to a refereed paper. 2The initial literature search was performed using the databases ENSDF [3] and NSR [7] of the National Nuclear Data Center at Brookhaven National Laboratory. These databases are complete and reliable back to the early 1960's. For earlier references, several editions of the Table of Isotopes were used [8][9][10][11][12][13]. A good reference for the discovery of the stable isotopes was the se...

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