Neutron capture cross sections of 232T/i have been measured relative to 197Au in the energy region from 30 keV to 600 keV. The neutron source was the reaction 7Li(p, n) produced on the 4 MV Van de Graaff Accelerator of the Centre d' Etudes Nucléaires de Bordeaux (CENBG). Preliminary analysis of the measurements indicates that the cross sections are closer to the JENDL database values.

We summarize here the results of the TARC experiment whose main purpose is to demonstrate the possibility of using Adiabatic Resonance Crossing (ARC) to destroy efficiently Long-Lived Fission Fragments (LLFFs) in accelerator-driven systems and to validate a new simulation developed in the framework of the Energy Amplifier programme. An experimental set-up was installed in a CERN PS proton beam line to study how neutrons produced by spallation at relatively high energy (En⩾1MeV) slow down quasi-adiabatically with almost flat isolethargic energy distribution and reach the capture resonance energy of an element to be transmuted where they will have a high probability of being captured. Precision measurements of energy and space distributions of spallation neutrons (using 2.5 and 3.5 GeV/c protons) slowing down in a 3.3 m×3.3 m×3 m lead volume and of neutron capture rates on LLFFs 99Tc, 129I, and several other elements were performed. An appropriate formalism and appropriate computational tools necessary for the analysis and understanding of the data were developed and validated in detail. Our direct experimental observation of ARC demonstrates the possibility to destroy, in a parasitic mode, outside the Energy Amplifier core, large amounts of 99Tc or 129I at a rate exceeding the production rate, thereby making it practical to reduce correspondingly the existing stockpile of LLFFs. In addition, TARC opens up new possibilities for radioactive isotope production as an alternative to nuclear reactors, in particular for medical applications, as well as new possibilities for neutron research and industrial applications.

The neutron capture cross section of Th-232 has been measured relative to sigma (n, gamma )for Au-197 and sigma (n,f) for U-235 in the energy range from 60 keV to 2 MeV. Neutrons were produced by the Li-7(p,n) and T(p,n) reactions at the 4-MV Van de Graaff Accelerator of CEN Bordeaux-Gradignan. The activation technique was used, and the cross section was measured relative to the Au-197(n,gamma) standard cross section up to 1 MeV The characteristic gamma lines of the product nuclei Pa-233 and Au-118 were measured with a 40% high-purity germanium detector. Above this energy, the reaction U-235(nf) was also used as a second standard, and the fission fragments were detected with a photovoltaic cell. The results, after applying the appropriate corrections, indicate that the cross sections are close to the JENDL-3 database values up to 800 keV and over 1.4 MeV. For energies in the intermediate range, our values are slightly lower than those from all the libraries.

Energy and space distributions of spallation neutrons (from 2.5 and 3.57 GeV/c CERN proton beams) slowing down in a 3.3 × 3.3 × 3 m3 lead volume and neutron capture rates on long-lived fission fragments 99Tc and 129I demonstrate that Adiabatic Resonance Crossing (ARC) can be used to eliminate efficiently such nuclear waste and validate innovative simulation.

beta-delayed one- and two-proton and alpha spectroscopic studies of the neutron-deficient nuclei Si-22,Si-23,Si-24 and Al-22 produced in projectile fragmentation of a Ar-36 primary beam at 95 MeV/u have been performed at GANIL. Isotopes of interest were analyzed using the LISE3 spectrometer and were implanted in a telescope made of silicon detectors and a micro-strip gaseous counter where decay particles were detected.

A relativistic primary beam of Ni-58 from the SIS synchrotron at GSI was used to produce proton-rich isotopes in the titanium-to-nickel region by projectile fragmention at the FRS. We report here on the first observation of the T-z = -7/2 nuclei Fe-45 and Ni-49. In addition, the new isotope Cr-42 (T-z = -3) was identified. This opens the route to the yet unobserved doubly-magic nucleus Ni-48.

β-delayed one- and two-proton and α spectroscopic studies of the neutron-deficient nuclei 22,23,24Si and 22Al produced in projectile fragmentation of a 36Ar primary beam at 95 MeV/u have been performed at GANIL. Isotopes of interest were analyzed using the LISE3 spectrometer and were implanted in a telescope made of silicon detectors and a micro-strip gaseous counter where decay particles were detected.

The use of accelerator driven system (ADS) like for instance the Energy Amplifier concept (EA) proposed by C. Rubbia and his group might be one of the solutions to solve the energy problem and in particular to answer the question: what could we do with the nuclear waste produced by the present nuclear reactors? We present in this paper the EA concept, which is illustrated by two experiments performed at the CERN-PS facility. One of them is the TARC (Transmutation by Adiabatic Resonance crossing) experiment which is designed to demonstrate the high efficiency offered by the EA to destroy the long-lived fission fragments.

In the TARC experiment the differential neutron flux phi(E, (r) over right arrow) of a spallation of 2.5 and 3.5 GeV/c proton in large lead block is measured in the range between 0.1 eV and 1.5 MeV. A new technique, using small quantities (less than 0.1 gram) of material. is used for measuring the transmutation rate as a function of neutron energy in the range between 0.1 eV up to a few keV. The method is applied to a target of 86 mg (Tc-99) mixed with 1.7 g of Aluminum. From these measurements the energy profile of the capture cross section can be extracted.

In an experiment at the LISE3 facility of GANIL, we used the projectile fragmentation of a 36Ar primary beam at 95 MeV/nucleon to produce the isotope 24Si. The beta decay half-life of 24Si has been determined to be T1/2 = (140 ± 8) ms, in agreement with earlier measurements. In addition to the decay of the isobaric analog state, several proton peaks are observed for the first time allowing to identify most of the Gamow-Teller transitions to unbound states and to present a partial decay scheme for 24Si. These results are compared with shell-model predictions.

23Si isotopes have been produced as projectile fragments of a 36Ar primary beam at 95 MeV/nucleon at the LISE3 spectrometer of GANIL. After implantation in a detector telescope, β-delayed one-proton and β-delayed two-proton emission has been observed. The main one-proton peaks are at (1.32±0.04)MeV, (2.40±0.04)MeV, and (2.83±0.06)MeV. The total decay energy for the β2p decay is (6.18±0.10)MeV for the decay to the ground state and (5.86±0.10)MeV for the decay to the first excited state in the daughter nucleus. However, energetically possible decays via βpα and β3p emission have not been identified. The spectra allowed us to determine the excitation energy of the isobaric analogue state in 23Al. This enabled us to calculate the coefficients of the T = 5/2 isobaric multiplet mass equation for A = 23. The mass excess of the 23Si ground state was deduced. This value is compared to different theoretical predictions. Additionally, we determined the branching ratios for the different decay branches. A half-life measurement yielded T1/2 = (40.7±0.4)ms.

The proton-rich nuclei Cr-44, Mn-47, Fe-48,Fe-49 and Co-50 have been produced by fragmentation of a Ni-58 beam at 650 MeV/u. The isotopic separation of these nuclei has been achieved with the GSI Projectile-Fragment Separator FRS. The isotopes have been identified in flight by Delta E-ToF-B rho measurements. After implantation in a stack of seven silicon detectors, the signals measured for implantation and radioactive decay were unambiguously correlated in time due to low counting rates. On the basis of the two proton peaks observed for Co-50 at (2034+/-30) keV and (2740+/-41) keV with a half-life of (44+/-4) ms, a partial decay scheme is proposed for this nucleus. A single proton peak at (959+/-33) keV was observed for Fe-48 with a half-life of (44+/-7) ms. This emission is attributed to the decay of the T = 2 isobaric analog state in Mn-48. No deviation from the quadratic form of the isobaric multiplet mass equation is observed. Additional information on beta-delayed proton branches of Fe-49, Cr-44 and Mn-47 was also obtained.

A primary beam of ${}^{58}$Ni at 600 MeV/nucleon from the SIS synchrotron at GSI was used to produce proton-rich isotopes in the titanium-to-nickel region by projectile fragmention on a beryllium target. The fragments were separated by a projectile-fragement separator and unambiguously identified. We report here the first observation of the ${T}_{z}\\phantom{\\rule{0ex}{0ex}}=\\phantom{\\rule{0ex}{0ex}}\\ensuremath{-}7/2$ nuclei ${}^{45}$Fe and ${}^{49}$Ni, the most proton-rich nuclei ever synthesized with an excess of seven protons. In addition, the new isotope ${}^{42}$Cr $({T}_{z}\\phantom{\\rule{0ex}{0ex}}=\\phantom{\\rule{0ex}{0ex}}\\ensuremath{-}3)$ was identified. According to commonly used mass predictions, these isotopes are all unbound with respect to two-proton emission from their ground states. From the nonobservation of ${}^{38}$Ti $({T}_{z}\\phantom{\\rule{0ex}{0ex}}=\\phantom{\\rule{0ex}{0ex}}\\ensuremath{-}3)$ in this experiment, an upper limit of 120 ns is deduced for the half-life of this isotope.