R. Armbruster

Mesure des pouvoirs d'arrêt de C, Ca, Au Et CaF2 pour des protons d'énergie comprise entre 0.4 et 6 MeV

Abstract Proton stopping powers have been measured for C, Ca, Au and AaF 2 in the energy region 0.4 to 6.0 MeV. The values of ΔE were obtained from the energy displacements, observed with a solid state junction, of the scattered proton beam when it traversed thin target films. The values of ΔX were obtained from weighings of the films. Numerous measurements on several targets of each substance, and rigid controls in all phases of target preparation and handling, have given stopping power values with a maximum probable uncertainty of ±3.5% for C, Ca and Au, and ±5% for CaF 2 . Mean excitation-ionization potentials are also calculated.

A spectroscopic study of 18F: (I). The 17O(p, p)17O and 17O(p, α0)14N reactions

Abstract The 17 O(p, p) 17 O and 17 O (p, α 0 ) 14 N reactions have been studied in the energy range E p = 0.5–1.33 MeV. Excitation functions for elastic scattering measured at several angles give l p values for six resonances and J π ; T values of 3 + ; 1 and 2 + ; 1 for the states at 6.16 and 6.28 MeV, respectively. From both reactions, J π limitations were found for six resonant levels. The 17 O(p, α 0 ) 14 N reaction also yields information on T -assignments and level formation parameters. Experimental results are discussed in terms of shell-model configurations.

A spectroscopic study of 18F: (II). The 17O(p, γ)18F reaction

Abstract Thirteen resonances corresponding to excitations between 6 and 7 MeV have been observed in the 17 O(p, γ) 18 F reaction between E p = 440 and 1440 keV. For most of the levels, precise energies, branching ratios, and resonance strengths were determined. In some cases, natural resonance widths and transition strengths could be given. A reaction Q -value of 5603 ± 3 keV was found. Angular distributions of γ-rays and γ-γ correlation measurements, together with 17 O(p, p) and 17 O(p , α 0 ) data, were used to determine J π values and mixing ratios. The levels are discussed in terms of weak coupling shell-model configurations.

Étude des niveaux de 38Ar formés dans la réaction 34S(α,γ)38Ar

Abstract Eighteen resonances were observed in the reaction 34 S(α,γ) 38 Ar, in the range E α = 3.6–4.8 MeV. Spins and parities have been determined by angular distribution and correlation measurements. The measured transition strengths and branching ratios are discussed.

Étude des niveaux du 32S formés au moyen de la réaction 28Si(α, γ)32S

Abstract Sixteen resonances were observed in the reaction 28 Si(α, γ) 32 S in the range E α = 4.2–6.0 MeV. Spins and parities have been determined by angular distribution and correlation measurements. The lifetime of the 4.29 MeV levels of 32 S was deduced from a Doppler-shift attenuation measurement as τ m = 94±30 fs. The transition strengths, deduced from measured resonance strengths and branching ratios, exhibit the expected inhibition of dipole transitions in self-conjugated nuclei.