[en] The values of the total kinetic energy (TKE) of fission fragments published until now show discrepancies up to several MeV's depending on the type of experiment. Therefore, a novel method was developed to get more reliable figures of high precision by avoiding systematic errors of earlier measurements. Moreover, the determination of primary fragment mass- and energy-distributions is feasible

[en] Experimental results obtained for thermal neutron induced fission of heavy nuclei are reviewed. The salient features observed in cold fragmentation for total kinetic energy TKE_max and for nuclear charges Z of fragments with given mass A are discussed and interpreted in terms of a scission point model

[en] An unexpectedly high probability of collisions between the fission particles and the atoms in an ionization chamber along the entire particle track causes a strong fluctuation of the shapes of the Bragg curves. This fluctuation imposes an upper limit of the charge resolution ΔZ/Z which can be achieved

[en] To study fission processes with high resolution and efficiency the instruments called ''Cosi fan tutte'' and ''DIOGENES'' were built at Institute Laue-Langevin, Grenoble. The design of the instruments are shown. First test results are presented. The instrument COST FAN TUTTE will study thermal neUtron induced fission reactions and take velocities, kinetic energies, final masses, initial masses, neutron emission numbers and nuclear charges of fragments. The ''Cosi fan tutte'' comprises a combination of a time-of-flight device and an energy detector for each of the two fragments. The facility ''DIOGENES'' is made up from two toroidal concentric ionization chambers surrounding the fissile targets. The inner chamber is to detect the fragments kinetic energies and emission angles while the outer one identifies the ternary light particle and measures their emission angles and residual energies. A first experiment has been run for ²³⁵U(n, f). Some 2x1O⁵ ternary fission events have been collected. The data are under evaluation and some preliminary results are given

[en] With the aim of determining masses of fission fragments by measuring velocities and kinetic energies, specially adapted time-of-flight detectors and ionization chambers were developed. The combination of both the time-of-flight and ionization chamber, to produce an energy-time-of-flight spectrometer, was tested with fragments from the /sup 235/U(n,f) reaction. In the light group of fission fragments, all masses are resolved individually with a mass resolving power m/δm = 170 for m = 95. At high energies also the heavy masses are resolvable. A possible nuclear-charge determination by the instrument is discussed

[en] The pulseheight response X of surface barrier detectors and an axial ionization chamber has been taken for fission fragments of given mass M and energy E. Fragments of accurately known M and E were obtained from the mass separator Lohengrin at the ILL. The energies on Lohengrin were calibrated by a time-of-flight technique, Pulse-height spectra from /sup 252/Cf(sf) were recorded in parallel. It could again be shown that the Energy E is well described by the relationship E = (a+a'M)X + (b+b'M). In the case of surface barrier detectors, the calibration constants desired differ, however, markedly from previously reported values. The new constants yield for the reaction /sup 235/U(n/sub th/,f) kinetic energies of the fission fragments which are in perfect agreement with recent velocity measurements

[en] Angular momenta of fission fragments are sometimes exceeding 10 ℏ for thermal neutron induced and spontaneous fission. This is surprising since in the latter case the mother nucleus may have zero spin (e.g. "2"5"2Cf). In theory fragment spins are explained as a quantum mechanical effect. It is argued that they are due to zero-point oscillations of fragments being deformed at scission. In contrast to current theory it is shown that, for the specific case of near-magic "1"3"2Te, a large spin is generated by thermal excitation of single-particle states. (author)

[en] The new built Cosi Fan Tutte facility installed at the High Flux Reactor of the ILL in Grenoble was used to obtain correlated mass, kinetic energy and nuclear charge of the fission fragments from U235(n/sub th/,f) and Th229(n/sub th/,f)

[en] Cold binary fission has been studied in the spontaneous decay of ²⁵²Cf (sf). Cold fission for the mass split 132/120 is especially interesting because here it is the doubly magic ¹³²Sn which is dominating the yield for a range of total excitation energies 0< TXE<10MeV. For the reaction ²⁴²Am(n,f) induced by thermal neutrons the yields of the heaviest cluster being emitted as ternary particles have been investigated at the mass spectrometer Lohengrin of the institute Laue-Langevin. The emission of the heaviest clusters (³³, ³⁴, ³⁵Si) is a cold process with all three reaction partners being born in or very close to their ground states

[en] The mass and energy distribution of fission fragments in /sup 249/Cf(n/sub th/,f) were determined by combining TOF and energy data of the fragments. The first results are discussed