W.G. Davies

Stopping power measurement for 19F, 24Mg, 27Al, 32S and 35Cl at energies ∼0.2 to ∼3.5 MeV/nucleon in Ti, Fe, Ni, Cu, Ag and Au

Abstract Stopping powers have been measured for beams of 19 F, 24 Mg, 27 Al, 32 S and 35 Cl for energies ∼0.2 to ∼3.5 MeV/nucleon in Ti, Fe, Ni, Cu, Ag and Au to an accuracy of ±4%. The results are compared with previous experimental values and with the semiempirical tabulation of Northcliffe and Schilling. A stopping power table for these six materials containing all projectiles in the range 8 ≤ Z ≤ 20 is presented.

The level structures of 85, 87Sr from (d, p) reactions

Abstract The reactions 84 Sr(d, p) 85 Sr and 86 Sr(d, p) 87 Sr have been studied at a bombarding energy of 12 MeV. Thirty-four levels below 4.5 MeV of excitation have been identified in 87 Sr and fifty-four levels below 3.5 MeV have been identified in 85 Sr. Transferred orbital angular momenta and spectroscopic information have been deduced from a DWBA analysis of the proton differential cross sections. It has been found that the lowest-lying excited states arise from 1g 9 2 , 2p 1 2 and 2p 3 2 configurations. The 1f 5 2 shell appears to be completely filled in these low-mass strontium isotopes.

Effective interaction among 1g92 and 2p12 neutrons in the strontium isotopes

Abstract In the seniority scheme an effective interaction shell-model calculation has been carried out for the low-lying structure of the strontium istopes. The model predictions are compared with existing experimental data and the quality of the seniority quantum number evaluated. Differences between effective neutron matrix elements have been determined and compared with the corresponding proton case. Comparisons of predicted two-neutron transfer cross sections with experimental data have been used to remove ambiguities in the sign of certain off-diagonal matrix elements.

EFFECTIVE INTERACTION AMONG 1g/sub 9/2/ AND 2p/sub 1/2/ NEUTRONS IN THE STRONTIUM ISOTOPES.

Abstract In the seniority scheme an effective interaction shell-model calculation has been carried out for the low-lying structure of the strontium istopes. The model predictions are compared with existing experimental data and the quality of the seniority quantum number evaluated. Differences between effective neutron matrix elements have been determined and compared with the corresponding proton case. Comparisons of predicted two-neutron transfer cross sections with experimental data have been used to remove ambiguities in the sign of certain off-diagonal matrix elements.

The use of 4He ion-implanted targets to obtain accurate nuclear lifetimes from analysis of doppler broadened lineshapes

Abstract The inverse reactions 4 He( 24 Mg, 4 He) 24 Mg and 4 He( 35 Cl, p) 38 Ar have been used to measure the mean lifetimes of the first excited states of 24 Mg and 38 Ar. The Doppler broadened lineshapes were analyzed using scaled experimental stopping powers and yielded results of 1.82 ±0.14 ps for the 1.37 MeV level in 24 Mg and 0.72 ± 0.05 ps for the 2.17 MeV level in 38 Ar.

The conservation of seniority in the 1g92 neutron shell

Abstract The results of one- and two-neutron transfer reactions across the strontium isotopes are applied to a study of the conservation of seniority in the 1 g 9 2 neutron shell.

Hole states of 20F and 20Ne

Abstract The structure of the low-lying states of 20F has been investigated with the reaction 21Ne(d, 3He)20F induced by 26 MeV deuterons. Spins, parity assignments and spectroscopic factors for the populated states are compared with the predictions of the Nilsson model and recent shell-model and projected Hartree-Fock calculations. The reaction 21Ne(d, t)20Ne, studied simultaneously, excites strongly the T = 1 states in 20Ne which are analogues of the low-lying states of 20F. The spectroscopic factors of parent and analogue are consistent to within 20% for states excited by a single l-transfer.

Study of low-lying states in 92Tc with the 92Mo(3He, t) reaction

Abstract States in 92 Tc have been studied by means of the 92 Mo( 3 He, t) reaction at 27.5 MeV. The Q -value for this reaction and the excitation energy of the isobaric ground state analogue of 92 Mo were determined to be −7.882 ± 0.030 MeV and 3.813 ± 0.030 MeV respectively. Strongly populated levels in 92 Tc appear to belong to configurations arising from the (1g 9 2 ) π (1g 9 2 ) ν −1 multiplet.

Effects of exchange and final-state interactions in the reactions 2H(3He, 3H p)p and 2H(3He, 3He p)n

Abstract Absolute coincidence cross sections for the 2 H( 3 He, 3 He p)n and 2 H( 3 He, 3 H p)p reactions were measured at E He = 35.9 MeV. Spectra dominated by the nucleon-nucleon final-state interaction (FSI) are fitted by a fully antisymmetrized PWBA theory which includes the effects of FSI in all its matrix elements. Previously reported 26.8 MeV data showing both FSI and quasi-elastic scattering (both with and without charge exchange) are also fitted by the theory, which qualitatively describes the shapes of all these spectra and the ratios of the cross sections for the various processes. Predictions of Watson-Migdal theory are fitted to the FSI spectra and differences between the two theories are analyzed.

Lifetimes of levels in 38Ar

Abstract The mean lifetimes of the Jπ = 0+and 5− levels in 38Ar at 3377 and 4585 keV have been easured to be 34 ± 5 ps and 196 ± 10 ps, respectively, using a coincidence recoil-distance Doppler-shift method and the 35Cl(α, pγ)38Ar reaction. The lifetime of the 4− level at 4480 keV excitation was measured to be 1.6−0.4+1.2 ps by the Doppler-shift attenuation method. All three lifetimes are significantly longer than recent theoretical predictions.