Ch. Veyssiere

Thermal neutron capture cross section for the K isomer {sup 177}Lu{sup m}

The thermal neutron radiative capture cross section for the K isomeric state in {sup 177}Lu has been measured for the first time. Several {sup 177}Lu{sup m} targets have been prepared and irradiated in various neutron fluxes at the Lauee Langevin Institute in Grenoble and at the CEA reactors OSIRIS and ORPHEE in Saclay. The method consists of measuring the {sup 178}Lu activity by {gamma}-ray spectroscopy. The values obtained in four different neutron spectra have been used to calculate the resonance integral of the radiative capture cross section for {sup 177}Lu{sup m}. In addition, an indirect method leads to the determination of the {sup 177}Lu{sup g} neutron radiative capture cross section.

Actinide Fission and Capture Cross Section measurements at ILL: the Mini‐INCA project

Fission cross section of short‐lived minor actinides is of prime importance for the incineration of minor actinides in high and thermal neutron fluxes. But due to the shortness of their half‐lives, measurements are difficult to handle on these isotopes and the existing data present some large discrepancies. An original method has been developed, in the framework of the Mini‐INCA project at ILL, to measure the fission and capture cross sections of minor actinides with low error bars associated even for short‐lived isotopes. This method lies on a quasi on‐line alpha‐ and gamma‐spectroscopy of irradiated samples and on the use of fission micro‐chambers. Coupled to a very powerful Monte‐Carlo simulation, both microscopic information on nuclear reactions (total and partial cross sections for neutron capture and/or fission reactions) and macroscopic information on transmutation and incineration potentials could be gathered. In this paper, the method is explained in its originality and some recent results are gi...

The Minor Actinide Transmutation‐Incineration Potential Studies in High Intensity Neutron Fluxes

In the framework of nuclear waste transmutation studies, the Mini‐INCA project has been initiated at CEA/DSM with objectives to determine optimal conditions for transmutation and incineration of Minor Actinides (MA) in high intensity neutron fluxes. Our experimental tools based on alpha‐ and gamma‐spectroscopy of irradiated samples and the development of fission micro‐chambers could gather both microscopic information on nuclear reactions (total and partial cross sections for neutron capture and/or fission reactions) and macroscopic information on transmutation and incineration potentials. Cross sections of selected actinides (241Am, 242Am, 242Pu, 237Np, 238Np) have already been measured at ILL, showing some discrepancies when compared to evaluated data libraries but in overall good agreement with recent experimental data.

Thermal Neutron Capture and Thermal Neutron Burn‐up of K isomeric state of 177mLu: a way to the Neutron Super‐Elastic Scattering cross section

Thermal neutron radiative capture and burn‐up measurements of the K isomeric state in 177Lu form part of an original method to indirectly obtain the neutron super‐elastic scattering cross section at thermal energy. Neutron super‐elastic scattering, also called neutron inelastic acceleration, occurs during the neutron collisions with an excited nuclear level. In this reaction, the nucleus could partly transfer its excitation energy to the scattered neutron.