Levels in Gd156 FED in the β-decay of Eu156

doi:10.1016/0029-5582(62)90173-6

Nuclear Physics

Volume 29, January–February 1962, Pages 153-176

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Abstract

The disintegration scheme of Eu¹⁵⁶ has been studied using the Chalk River high-resolution β-ray spectrometer, scintillation spectrometers and coincidence techniques. The internal conversion electron spectrum was studied at momentum resolution settings in the range 0.02–0.08%. Conversion lines were observed corresponding to 28 γ-transitions in Gd¹⁵⁶ of energies in keV: 88.97 (E2), 199.19 (E2), 599.5 (E1), 646.3 (E1), 709.9, 723.5, 811.8 (M1), 865.8, 867.1 (E1), 960.8 (E1), 1040.5, 1049.5, 1065.1 (E2), 1079.2, 1153.4 (E1), 1154.0 (E2), 1168.5, 1230.7 (E1), 1242.4 (E1), 1277.4, 1366.4 (E1), 1876.8 (M1, E2), 1937.5 (M1, E2), 1965.8 (M1, E2), 2026.4 (M1, E2), 2097.8 (M1, E2), 2181.0 (M1, E2) and 2186.8 (M1, E2). The multipolarity assignments for the two lowest energy transitions were deduced from the L sub-shell conversion line intensity ratios; the others are based on the K-conversion coefficients deduced in this work. The β-ray spectrum of Eu¹⁵⁶ has at least four components of energies 2430±10 keV (33%), 1195±15 keV (14%), 485±20 keV (36%) and a low energy component of < 350 keV (≈ 17%). A β-γ coincidence experiment shows that the 2430 keV component feeds the ground state of Gd¹⁵⁶. Considerations of gamma-ray energy sums and γ-γ coincidence experiments establish levels in Gd¹⁵⁶ at energies in keV of 0(0+), 88.97 (2+1), 288.16 (4+), 1154.0 (2+) 1242.4 (1−), 1319.7, (2−), 1366.4 (1−) 1965.8 (1,2+), 2026.4 (1,2+), 2181.0 (1, 2+) 2186.8 (1, 2+) and 2203.4 (0, 1, 2+). Most of the low spin levels in Gd¹⁵⁶ which are fed in the β-decay of Eu¹⁵⁶ (0) were not observed in the electron capture decay of Tb¹⁵⁶(3, 4−).

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Levels in Gd156 FED in the β-decay of Eu156

Abstract

Nuclear Physics

Nucl. Instr. Methods

J. Inorg. and Nuclear Chem.

Nuclear Physics

Mat. Fys. Medd. Dan. Vid. Selsk.

Nuclear Physics

Bull. Am. Phys. Soc.

Bull. Am. Phys. Soc.

Bull. Am. Phys. Soc.

Levels in Gd¹⁵⁶ FED in the β-decay of Eu¹⁵⁶