[en] A technique for the preparation of homogeneous minor-actinide layers by the multiple-painting method is described in detail. The advantages of the method used, as well as characteristics of the layers, are discussed

No abstract available

No abstract available

[en] High resolution measurements of fission observables can be done with the recoil mass spectrometer Lohengrin at the Institut Laue-Langevin in Grenoble, France, which was designed to measure fission fragment characteristics from neutron induced fission. The mass separator permits the placement of an actinide layer in a high thermal neutron flux. It separates fragments according to atomic mass, kinetic energy and ionic charge state by the action of magnetic and electric fields, and allows us to determine these distributions, isotopic yields, and the fragment gamma-decay characteristics. Almost all fissile isotopes ranging from Th to Cf have been investigated with Lohengrin, and in particular mass and nuclear charge distributions for light fission products have been determined. The experimental set-up used to investigate the mass yield and the fission fragment kinetic energy distributions in the heavy mass region, or in the light mass region, is done by coupling a high resolution ionization chamber to the spectrometer. For low mass fission products a double anode ionization chamber is used to determine furthermore isotopic yields within a mass line. For fission fragments of higher mass this separation is no longer possible, and gamma-spectrometry is used instead to identify the contributing nuclear charges. The experimental set-up is shortly described in the present paper, and we present preliminary results for measurements of thermal neutron induced fission in ²³⁵U(n,f), ²³⁹Pu(n,f) and ²⁴¹Pu(n,f). (authors)

[en] The stopping power of fission fragments from ²⁵²Cf(sf) has been measured in thin foils of C, Ni, Au, Al₂O₃ and Mylar as a function of fragment mass and energy. The chosen stopping materials are frequently used as the backing of sources and targets or entrance windows of gas detectors. The experimental setup allowed registration of velocities of two fission fragments and energy of one of them. In this way fragment masses could be unambiguously determined and the pulse-height defect of the silicon detector verified. The measured stopping power data for fission fragments cover masses between A = 101 and A = 148. The results are compared with semi-empirical predictions of SRIM 2003 code, LSS theory and theoretical calculation by Sigmund (PASS code). The best representations of the data are achieved by a semi-empirical formula based on classical Bohr theory. The formula was successfully tested also on the available data for Ar, Ca, Kr, Xe and Au ions in the energy range 0.2-6 MeV/u slowing down in carbon, nickel and gold