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The time differential perturbed angular distribution technique with LaBr 3 detectors has been applied to the I π = 11 2 − isomeric state (E x = 846 keV, τ = 107 ns) in 107 Cd, which was populated and recoil-implanted into a gadolinium host following the 98 Mo(12 C, 3n) 107 Cd reaction. The static hyperfine field strength of Cd recoil implanted into gadolinium was thus measured, together with the fraction of nuclei implanted into field-free sites, under similar conditions as pertained for a previous implantation perturbed angular distribution g-factor measurement on the I π = 10 + state in 110 Cd. The 110 Cd g(10 +) value was thereby reevaluated, bringing it into agreement with the value expected for a seniority-two νh11 /2 configuration.

Background: The even cadmium isotopes near the neutron midshell have long been considered among the best examples of vibrational nuclei. However, the vibrational nature of these nuclei has been questioned based on E2 transition rates that are not consistent with vibrational excitations. In the neighbouring odd-mass nuclei, the g factors of the low-excitation collective states have been shown to be more consistent with a deformed rotational core than a vibrational core. Moving beyond the comparison of vibrational versus rotational models, recent advances in computational power have made shell-model calculations feasible for Cd isotopes. These calculations may give insights into the emergence and nature of collectivity in the Cd isotopes.Purpose: To investigate the nature of collective excitations in the A ∼ 100 region through experimental and theoretical studies of magnetic moments and electromagnetic transitions in 111 Cd. Method:The spectroscopy of 111 Cd has been studied following Coulomb excitation. Angular correlation measurements, transient-field g-factor measurements and lifetime measurements by the Doppler-broadened line shape method were performed. The structure of the nucleus was explored in relation to particle-vibration versus particlerotor interpretations. Large-scale shell-model calculations were performed with the SR88MHJM Hamiltonian.Results: Excited-state g factors have been measured, spin assignments examined and lifetimes determined. Attention was given to the reported 5/2 + 753-keV and 3/2 + 755-keV states. The 3/2 + 755-keV level was not observed; evidence is presented that the reported 3/2 + state was a misidentification of the 5/2 + 753-keV state.Conclusions: It is shown that the g factors and level structure of 111 Cd are not readily explained by the particlevibration model. A particle-rotor approach has both successes and limitations. The shell-model approach successfully reproduces much of the known low-excitation structure in 111 Cd.

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We have performed measurements of sodium nuclear recoils in NaI:Tl crystals, following scattering by neutrons produced in a 7Li(p,n)7Be reaction. Understanding the light output from such recoils, which is reduced relative to electrons of equivalent energy by the quenching factor, is critical to interpret dark matter experiments that search for nuclear scattering interactions. We have developed a spectrum-fitting methodology to extract the quenching factor from our measurements, and report quenching factors for nuclear recoil energies between 36 and 401 keV. Our results agree with other recent quenching factor measurements that use quasi-monoenergetic neutron sources. The new method will be applied in the future to the NaI:Tl crystals used in the SABRE experiment.

The conversion electrons from the decay of the 35.5-keV excited state of 125 Te following the electron capture decay of 125 I have been investigated at high resolution using an electrostatic spectrometer. The penetration parameter λ = −1.2(6) and mixing ratio |δ(E2/M 1)| = 0.015(2) were deduced by fitting to literature values and present data. The shake probability of the conversion electrons is estimated to be 0.5, more than two times larger than the predicted value of 0.2.

The emergence of nuclear collectivity near doubly-magic 132 Sn was explored along the stable, eveneven 124−130 Te isotopes. Preliminary measurements of the B(E2; 4 + 1 → 2 + 1 ) transition strengths are reported from Coulomb excitation experiments primarily aimed at measuring the g factors of the 4 + 1 states. Isotopically enriched Te targets were excited by 198-205 MeV 58 Ni beams. A comparison of transition strengths obtained is made to large-scale shell-model calculations with successes and limitations discussed.

A new tabulation of electronic factors is reported for electron conversion for elements of Z from 5 to 126 and electronic factors for electron-positron pair conversion for elements of even Z from 4 to 100.The electronic factors for electron conversion, Ω CE (E0), were calculated using a modified version of the CATAR program developed by Pauli and Raff with a relativistic-Hartree-Fock-Slater approach (Comp. Phys. Comm. 9 (1975) 392). The electronic factors for electron-positron pair conversion, Ω IP F (E0), were calculated using the model developed by Wilkinson (Nucl. Phys. A133 (1969) 1). The data tables presented here cover all atomic shells up to R2 and transition energies from 1 keV to 6000 keV and from 1100 keV to 8000 keV for pair conversion. A comparison with previous electronic factor tabulations is presented. Ratios of experimental Ω(E0) values for 83 E0 transitions in 8 ≤ Z ≤ 98 are compared to this tabulation. Two examples of how to use the tabulation to extract E0 strengths are also included.