[en] Short communication

[en] Direct mass measurements of A=80 isobars were performed using the second cyclotron of SARA (systeme accelerateur rhone-alpes) of the ISN (institut des sciences nucleaires) in Grenoble as a time-of-flight mass spectrometer. Using the 300 MeV ⁵⁸Ni+²⁷Al reaction, the isobars ⁸⁰Rb,⁸⁰Sr,⁸⁰Y, and ⁸⁰Zr (only one event.) were measured. For ⁸⁰Y we found a mass value of 79.934320(180) u, corresponding to a decay energy Q (⁸⁰Y→⁸⁰Sr) of (9120± 170) keV. Comparing this value to the former experiments of Lister et al. and Della Negra et al. results in a difference of about 2.2 MeV. However, it does agree with the recommended value of Audi and Wapstra, which is derived from systematic trends. For ⁸⁰Zr the single event was identified with a probability of 0.999975 and a mass value of 79.940400(1600) u could be deduced from our experiment. (orig.)

[en] Transfer reactions at four near-barrier energies for the systems ³²S+^102,104Ru were studied. The differential cross sections of the strong transfer channels were measured with an experimental set-up yielding good mass number, nuclear charge and energy resolution. With a semiclassical coupled channel model the measured transfer cross sections were analyzed and transfer form factors were extracted. At energies even slightly above the Coulomb barrier, slope anomalies were observed. If the reasons for slope anomalies are not taken into account, the determination of transfer form factors out of such measurements can be incorrect. It is shown in this paper how such a wrong determination of form factors can be avoided even when slope anomalies occur. With the help of the extracted transfer form factors fusion excitation functions and barrier distributions of the systems ³²S+^102,104Ru were calculated. This proves that transfer channels play an important role in sub-barrier fusion processes for the studied systems. (orig.)

[en] Accurate mass measurements were performed using the second cyclotron of SARA (Systeme Accelerateur Rhone-Alpes) of the ISN (Institut des Sciences Nucleaires) in Grenoble as a time-of-flight mass spectrometer. Using the 300 MeV ⁵⁸Ni + ²⁷Al reaction proton-rich A=80 isobars were measured. For example ⁸⁰Y which is very interesting, due to the 2.2 MeV difference between the experimental mass value and the recommended value by Audi and Wapstra. (orig.)