Mean lifetimes of levels in 55Co

doi:10.1016/0375-9474(76)90156-1

Nuclear Physics A

Volume 261, Issue 3, 3 May 1976, Pages 427-438

https://doi.org/10.1016/0375-9474(76)90156-1 Get rights and content

Abstract

The mean lifetimes of levels in ⁵⁵Co below 5.2 MeV have been investigated with the Doppler-shift attenuation method and the ⁵⁴Fe(³He, d)⁵⁵Co reaction at 12 MeV. Scattered particles were detected in two E-ΔE telescopes at ±55° with respect to the beam axis, in coincidence with γ-rays observed at 90° and 130° in a 50 cm³ Ge(Li) detector. Mean lifetimes are reported for the following levels (energy in keV, lifetime in fs): 2166 (139±18), 2566 (680±200), 2923 (>245), 2939 (190±65), 3303 (99±22), 3323 (54±15), 3642 (680₋₃₀₀⁺⁴⁰⁰), 3943 (>170), 4164 (54±15), 4180 (<16), 4722 (<33), 4749 (<70) and 5174 (<40). The experimental results are compared with a detailed shell-model calculation.

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Nuclear Data Sheets for A = 55
2008, Nuclear Data Sheets
Nuclear data sheets update for A = 55
1991, Nuclear Data Sheets
Nuclear data sheets for A = 55
1985, Nuclear Data Sheets
Analysing powers of the 54Fe(He,d)55Co and 54Fe(3He, α)53Fe reactions
1981, Nuclear Physics, Section A
The differential cross sections and analysing powers of the ⁵⁴Fe(³He, d)⁵⁵Co and ⁵⁴Fe(³He, α)⁵³Fe reactions were measured for strong transitions populating both T_< and T_> states of the final nuclei using a 33 MeV polarized ³He beam. The sensitivity of the analysing powers to the total angular momentum transfer allowed model-independent determination of spins for all levels observed. The main features of the experimental data could be reproduced satisfactorily by the DWBA formalism only with certain combinations of the optical-model potentials. The analysing power of the indirect transition, when compared with coupled-reaction calculations, show a marked sensitivity to the reaction mechanism.
A study of some resonances in the 54Fe(p, γ)55Co reaction
1980, Nuclear Physics, Section A
Excitation functions for the ⁵⁴Fe(p, γ)⁵⁵Co reaction have been recorded in the energy region E_p = 1100–1760 keV. The decay schemes and branching ratios of ten resonances have been investigated. Angular distributions of primary γ-rays have been measured for three resonances to establish resonance spins. Resonance strengths for six resonances and gamma widths for three resonances have been determined. The isobaric analogues of the ground ( $J^{π} = 72^{−}) and 1919 keV$ $J^{π} = 32$ ⁻) states of the parent nucleus ⁵⁵Fe have been identified at 4722 and 6712 keV respectively in ⁵⁵Co. The Coulomb displacement energies of the observed analogue pairs (0–4722 keV) and (1919–6712 keV) have been obtained. The strengths of the possible analogue-antianalogue transitions for the proton capture state at E_p = 1679 keV have also been determined.
The 58, 60, 62, 64Ni(p, α)55, 57, 59, 61Co reactions and their description by the semi-microscopic model for three-nucleon transfer
1979, Nuclear Physics, Section A
The (p, α) reaction on the even-A nickel isotopes has been studied at an incident proton energy of 30 MeV. Between 14 and 26 states, or groups of states, were analysed for each of the residual cobalt isotopes. For these transitions angular distributions were determined from θ_lab = 7.5° to 70°. In all reactions the proton-hole states $(0 f_{72}, 1 s_{12} and 0 d_{32})$ stand out in the spectra. Also, states formed by the weak-coupling of the proton-holes to excitations of the neutron core were seen. Differences in the relative strengths of the positive-parity hole states between the proton pickup and the (p, α) data can be explained by a semi-microscopic model for three-nucleon transfer. Also the strength distribution of the transitions to the lowest weak-coupling quintuplet is correctly predicted. These results underline the importance of the inclusion of non-zero coupled neutron pairs into the description of (p, α) reactions. Several T_> states are observed in the ⁵⁸Ni(p, α)⁵⁵Co reaction.

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^☆: Work supported in part by the US Energy Researcand Development Administration.

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Nuclear Physics A

Abstract

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Nuclear Data Sheets for A = 55

Nuclear data sheets update for A = 55

Nuclear data sheets for A = 55

Analysing powers of the <sup>54</sup>Fe(He,d)<sup>55</sup>Co and <sup>54</sup>Fe(<sup>3</sup>He, α)<sup>53</sup>Fe reactions

A study of some resonances in the <sup>54</sup>Fe(p, γ)<sup>55</sup>Co reaction

The <sup>58, 60, 62, 64</sup>Ni(p, α)<sup>55, 57, 59, 61</sup>Co reactions and their description by the semi-microscopic model for three-nucleon transfer

Mean lifetimes of levels in 55Co☆

Abstract

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Mean lifetimes of levels in ⁵⁵Co☆