Some new properties of 254Es and 255Es

Fields, P. R.; Diamond, H.; Friedman, A.M.; Milsted, J.; Lerner, J.; Barnes, R.F.; Sjoblom, R.K.; Metta, D.N.; Horwitz, E.P.

doi:10.1016/0375-9474(67)90725-7

Cited by 27 publications

(5 citation statements)

References 15 publications

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“…Contrary to some previous predictions, the conclusion was that odd-odd nuclides cannot be expected to have a significantly greater stability against spontaneous fission than cor responding odd-A nuclei. On the other hand, Fields et al (117) have had another look at 254Es and have come up with the result that its half-life is longer than 2.5 X 107 years, which is inconsistent with this conclusion.…”

Section: Other Work On Transuranium Elementsmentioning

confidence: 84%

“…If the upper oxidation states are stable, volatile hexa-or octafluorides might be useful for chemical separa tion purposes. Certain predicted volatility characteristics of compounds of elements 115,116,117, and 118 (eka-bismuth, eka-polonium, eka-astatine, and eka-radon) may offer advantages; this of course is especially true for element 118. The predicted electronic structures (182) of these elements are included in Table VIII Table. 3.4.6 Procedures for chemical identification of new elements.-Predictions of the chemical properties of the heavy elements enable the investigator to devise identification procedures based on separative techniques such as ion exchange, volatility processes, precipitation reactions, solvent extraction, and oxidation-reduction reactions in aqueous solution.…”

Section: Seaborgmentioning

confidence: 96%

“…2.6.6 Einsteinium, fermium isotopes.-The synthesis of several new isotopes of einsteinium and fermium and the measurement of additional radio active properties of other isotopes of these elements have been accomplished by investigators in the USA (117,121,122,(130)(131)(132)(133)(134) and in the USSR (135,136) as shown in Table IV. 2.6.7 Short-lived spontaneous fission isotopes of fermium.-Hulet et al (134) of the Lawrence Radiation Laboratory at Livermore have attempted, without success, to observe the formation of 268Fm by neutron irradiation of !li7Fm in the ultra-high flux of a Savannah River reactor, which indicates that this much sought-after isotope has a T1/2< 5 sec if formed with a I-barn cross section. Also of interest are : the recent observation that 246Fm, nomi nally a 1.2-sec alpha-particle emitter, also decays by spontaneous fission, the ratio of spontaneous fission events to alpha-decay events being about 0.08 (130) ; the observation that 248Fm decays by spontaneous fission (0.…”

Section: Other Work On Transuranium Elementsmentioning

confidence: 99%

See 2 more Smart Citations

Elements Beyond 100, Present Status and Future Prospects

Seaborg¹

1968

Annu. Rev. Nucl. Sci.

141

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Section: Other Work On Transuranium Elementsmentioning

confidence: 84%

Section: Seaborgmentioning

confidence: 96%

Section: Other Work On Transuranium Elementsmentioning

confidence: 99%

See 1 more Smart Citation

Elements Beyond 100, Present Status and Future Prospects

Seaborg¹

1968

Annu. Rev. Nucl. Sci.

141

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“…FIELDS etal. [6] in 1967 reported a value of 338 barns in an ORR irradiation in which a(Co) = 36 barns was used. The first two-group measurement was made by FOLGER etal.…”

Section: Resultsmentioning

confidence: 99%

“…(39 3h) [6] in 1967 reported an effective cross section of 13 barns in an ORR irradiation based upon a(Co) = 36 barns. A two-group measurement made at Savannah River in 1972 by HARBOUR and MACMURDO [8] gave a th < 3 and I = 4299 ±218 barns using a th (Co) = 37.3 and /(Co) = 70 barns with a 0.412 eV cutoff.…”

Section: Resultsmentioning

confidence: 99%

The Thermal Neutron Capture Cross Section and Resonance Integral of ²⁵³Es¹

et al. 1984

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Es capture cross sections/Thermal cross sections and resonance integrals!Formation of ls,m Esand" 4 *Es AbstractIntegral neutron cross sections have been measured for 2S3 Es. The partial thermal capture cross sections and resonance integrals forming the 39.3-hour 2 S4m Es and the 276-day 2 54g Es relative to cobalt standards are reported. Analysis of alpha spectra in experiments measuring 254m Es formation gives σ^, = 178 ± 15 and / = 3750 ± 200 barns. Mass spectrographs analyses in experiments measuring 254g Es formation give a t h = 5.8 ± 0.7 and / = 114 ±7 barns.In this paper we describe the measurement of the neutron capture cross section of 253 Es. 253 Es captures neutrons to form the 39.3-hour isomer, 2S4m Es, as well as the 275.7-day ground state 254g Es. (See Fig. 2.) Because of the marked difference in the spin states of these two nuclides, no isomeric transition has been detected in the decay of 254m Es to form 254g Es. Thus, neutron capture in 2S3 Es to form 254g Es provides the only pathway to that isotope. Capture in 253 Es to form 254m Es has the consequence of lowering the 2S4g Es yield by burning out the 253 Es target.

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