The β-decay properties of the neutron-deficient nuclei 25 Si and 26 P have been investigated at the GANIL/LISE3 facility by means of charged-particle and γ-ray spectroscopy. The decay schemes obtained and the Gamow-Teller strength distributions are compared to shell-model calculations based on the USD interaction. B(GT ) values derived from the absolute measurement of the β-decay branching ratios give rise to a quenching factor of the Gamow-Teller strength of 0.6. A precise half-life of 43.7 (6) ms was determined for 26 P , the β −(2)p decay mode of which is described.PACS. 29.30.Ep Charged-particle spectroscopy -29.30.Kv X-and gamma-ray spectroscopy -23.90.+w

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In an experiment at the SISSI-LISE3 facility of GANIL, the decay of the proton drip line nucleus 45Fe has been studied. Fragment-implantation events have been correlated with radioactive decay events in a 16x16 pixel silicon-strip detector. The decay-energy spectrum of 45Fe implants shows a distinct peak at (1.14+/-0.04) MeV with a half-life of T(1/2)=(4.7(+3.4)(-1.4)) ms. None of the events in this peak is in coincidence with beta particles. For a longer correlation interval, daughter decays of the two-proton daughter 43Cr can be observed after 45Fe implantation. The decay energy for 45Fe agrees nicely with several theoretical predictions for two-proton radioactivity.

We have measured the Coulomb dissociation of 8 B into 7 Be and proton at 254 MeV/nucleon using a large-acceptance focusing spectrometer. The astrophysical S17 factor for the 7 Be (p,γ) 8 B reaction at Ec.m. = 0.25 − 2.78 MeV is deduced yielding S17(0) = 20.6±1.2 (exp.) ± 1.0 (theo.) eV-b. This result agrees with the presently adopted zero-energy S17 factor obtained in direct-reaction measurements and with the results of other Coulomb-dissociation studies performed at 46.5 and 51.2 MeV/nucleon. PACs: 25.40.Lw, 25.70.De, 26.65.+t The precise knowledge of the solar thermonuclear fusion of 8 B (from 7 Be plus proton) is crucial for estimating the 8 B solar neutrino flux and the predicted neutrino rates in terrestrial neutrino measurements. The relevant 7 Be(p,γ) 8 B cross section σ(E) is parameterized in terms of the astrophysical factor S 17 (E) which is defined by2 /hv is the Sommerfeld parameter. The flux of 8 B solar neutrinos is particularly important for the results of the Homestake, Super Kamiokande, and SNO experiments [1] which measure high-energy solar neutrinos mainly or solely from the 8 B decay. Unfortunately, this cross section has not been known with sufficient accuracy for a long time, despite the fact that several comprehensive direct measurements were reported for the 7 Be(p,γ) 8 B reaction [2][3][4][5][6]. The main difficulty in such experiments is the determination of the effective target thickness of the radioactive 7 Be target. This difficulty is reflected in the fact that the results of these measurements can be grouped into two distinct data sets which agree in their energy dependence but disagree in their absolute normalization by about 30%. In view of this discrepancy, experimental studies with different methods are highly desirable.As an alternative approach one can measure the inverse process, the Coulomb dissociation (CD) of 8 B into 7 Be and proton [7]. The CD yields are enhanced because thicker targets can be used and a larger phase space is available for CD. This method uses stable targets and thus is free from the difficulty of determining the effective target thickness. On the other hand, direct (p,γ) and Coulomb dissociation measurements have different sensitivities to the multipole composition of the photon fields. The E2 amplitude is enhanced in CD due to the large flux of E2 virtual photons, whereas it can be neglected in the (p,γ) reaction.Recently, Motobayashi et al. have performed a CD experiment at E( 8 B) = 46.5 MeV/nucleon, yielding values for S 17 in the energy range 0.6−1.7 MeV [8]. The extracted (p,γ) cross section is consistent with the results from the lower group of direct-reaction data points [4][5][6]. Another measurement at 51.9 MeV/nucleon by the same group with improved accuracy led essentially to the same conclusion [9].In this article, we report on an experiment of the CD of 8 B at a higher energy of 254 MeV/nucleon performed at the SIS facility at GSI, Darmstadt, Germany. The present incident energy has several advantages compared to those used in Refs. ...

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-The spallation residues produced in the bombardment of 56 F e at 1.5, 1.0, 0.75, 0.5 and 0.3 A GeV on a liquid-hydrogen target have been measured using the reverse kinematics technique and the Fragment Separator at GSI (Darmstadt). This technique has permitted the full identification in charge and mass of all isotopes produced with cross-sections larger than 10 −2 mb down to Z = 8. Their individual production cross-sections and recoil velocities at the five energies are presented. Production cross-sections are compared to previously existing data and to empirical parametric formulas, often used in cosmic-ray astrophysics. The experimental data are also extensively compared to different combinations of intra-nuclear cascade and de-excitation models. It is shown that the yields of the lightest isotopes cannot be accounted for by standard evaporation models. The GEMINI model, which includes an asymmetric fission decay mode, gives an overall good agreement with the data. These experimental data can be directly used for the estimation of composition modifications and damages in materials containing iron in spallation sources. They are also useful for improving high precision cosmic-ray measurements.