[en] The geometrical efficiency equation for a proton recoil telescope exposed to a monoenergetic point neutron source is solved by a power series expansion that permits simple and accurate reduction of raw telescope data to absolute neutron fluxes or source strengths. Two parameters are allotted for description of source anisotropy and three parameters are allotted for description of hydrogen scattering anisotropy in the center-of-mass system. The relativistic transformation of the hydrogen differential scattering cross section from center-of-mass to laboratory system is used

No abstract available

No abstract available

[en] The present work outlines a procedure to optimise the experimental parameters for elastic recoil detection analysis (ERDA). (author)

[en] Retention of He implanted into W single crystals and the He irradiation effects on H behavior were studied by ion beam analysis techniques. During implantation of ⁴He⁺ with 2-10 keV at 295 K, an accumulation of H started in the He implanted layer when the retained He concentration saturated. For the crystal irradiated by 10 keV He⁺ at 820 K, a remarkable increase of H was found in the He saturated layer, after stopping the implantation and cooling down the crystal below 400 K. Though blisters and exfoliation were observed for the surface irradiated at 820 K, less lattice disorder was found in the implanted layer and the thermal release of H occurred at lower temperature, in comparison with the crystal implanted at 295 K

[en] The glancing angle geometry is chosen to enable application of the elastic recoil detection microanalysis on thick geological samples, for hydrogen content determination. Simultaneous PIXE measurements can be used to eliminate the problem of uncertainties in beam charge collection. The method is applied to determine the hydration characteristics of silicates, produced experimentally at high pressure and temperature simulating the lower crust and upper mantle conditions. Preliminary results show that the technique can be applied readily on a microscopic (<100 μm) scale for determination of H at fraction of atomic percent level. 9 refs., 3 figs

[en] In Paris, we are using an atom interferometer to precisely measure the recoil velocity of an atom that absorbs a photon. In order to reach a high sensitivity, many recoils are transferred to atoms using the Bloch oscillations technique. In this paper, I will present in details this technique and its application to high precision measurement. I will especially describe in details how this method allows to perform an atom recoil measurement at the level of 1.3×10−9. This measurement is used in the most precise determination of the fine structure constant that is independent of quantum electrodynamics.

[en] A general treatment of indirect recoil implantation following nuclear reactions is given for the first time. This method allows implantation into any substrate of a wide range of species produced by nuclear reactions either in a thin sacrificial target or from a solid target. It is demonstrated that this can be done whilst avoiding primary beam damage to the substrate. Two cases are considered, the general one in which non-elastic nuclear reactions produce the recoil species of interest and secondly the special case of elastic recoils. In both cases a number of novel features of the process not previously described are outlined. For example, by controlling the angular acceptance of the substrate for recoil products the method can be tailored to give well controlled implantation profiles very similar to direct implantation (i.e., approximately Gaussian in range) or more extensive depth distributions whose profiles are simply determined by the centre of mass angular distribution of the reaction product. The flux of particles available for implantation is approximately 10^-4 smaller than from direct implantation facilities, but is comparable to the useful implantation dose achieved by the established technique of direct elastic recoil implantation. The radiation damage is little more than that associated with the indirect implant itself in contrast to direct elastic recoil implantation where the potential damage produced often mediates against the use of that technique. The main advantage of this relatively new method over the conventional methods is the wider range of species which can be implanted with minimum damage to the substrate. These include elements which cannot be conveniently produced from ion sources as well as exotic species which cannot be produced other than by nuclear reactions; radioactive species are good examples of both cases. (orig.)

[en] A recently-developed numerical procedure for the reconstruction of the neutron and gamma energy-spectra (by unfolding the recoils) is presented together with test results using a response function from a large liquid scintillator NE-213 and various experimental and simulated recoil spectra. The basic problem in spectra-unfolding is the instability of the backward transformation, which leads to useless pseudo-solutions unless special care is taken. The essential improved performance of the new method is due to the suppression of the pseudo-components by two measures: the energy distribution is approximated by a sum of either harmonic or Legendre polynomial basis functions (thus preventing high-frequency spurious oscillations) and this spectrum is constrained to be nonnegative. The basis functions are folded with the response function and then used as components for a constrained least-square fit to the pulse-height data. So the essence of the procedure is a sequence of multi-parameter minimizations subject to a set of inequality constraints. (Auth.)

[en] A liquid hydrogen system has been developed that serves as a scatterer for the High-Acceptance Recoil Polarimeter (HARP). In order to satisfy the conflicting design requirements regarding safety, the volume of the system, the energy loss of the recoiling protons, and the location of the cryogenic unit, a self-supporting thin-walled modular cryogenic system has been developed. The system was successfully operated during two commissioning runs of HARP in a high-luminosity electron scattering environment. The operational parameters of the system have been continuously monitored and are quantitatively understood