Energy and target material dependence of the neutron yield induced by proton and deuteron bombardment

The neutron yield for compact accelerator driven neutron sources depends on the target material, the ion type and its energy. When such sources are operated with low energy proton beams below 30 MeV, typical target materials are lithium and beryllium. New developments indicate that higher energies or a deuteron beam might be useful to increase the neutron yield at constant accelerator power. Here we present the total neutron yield analytically calculated for protons and deuterons at energies up to 100 MeV for various target materials. The total neutron yield depends on the involved cross sections and the stopping power of the target material. This study shows that for energies lower than 30 MeV light target materials with a deuteron beam are preferable whereas for energies above 30 MeV heavy target materials show a high neutron yield with little difference for a proton or deuteron beam.

Sensibility of grey particle production system to energy and centrality in 60A and 200A GeV 16O–Nucleus interactions

The grey particle production following 60 A and 200[Formula: see text]A GeV [Formula: see text]O interactions with emulsion nuclei is investigated at different centralities. The evaporated target fragment multiplicity is voted as a centrality parameter. The target size effect is examined over a wide range, where the C, N and O nuclei present the light target group while the Br and Ag nuclei are the heavy group. In the framework of the nuclear limiting fragmentation hypothesis, the grey particle multiplicity characteristics depend only on the target size and centrality while the projectile size and energy are not effective. The grey particle is suggested to be a multisource production system. The emission direction in the 4[Formula: see text] space depends upon the production source. Either the exponential decay or the Poisson’s peaking curves are the usual characteristic shapes of the grey particle multiplicity distributions. The decay shape is suggested to be a characteristic feature of the source singularity while the peaking shape is a multisource super-position. The sensibility to the centrality varies from a source to other. The distribution shape is identified at each centrality region according to the associated source contribution. In general, the multiplicity characteristics seem to be limited w.r.t. the collision system centrality using light target nuclei. The selection of the black particle multiplicity as a centrality parameter is successful through the collision with the heavy target nuclei. In the collision with the light target nuclei it may be qualitatively better to vote another centrality parameter.

Transverse and Longitudinal Lambda Polarization in Lepton Scattering by Unpolarized Nucleons at HERMES

Transverse and longitudinal polarization of [Formula: see text] hyperons has been studied. The transfere of polarization from high-energy positron to [Formula: see text] hyperon has been measured. The longitudinal spin transverse coefficient is found to be [Formula: see text] = [Formula: see text]. The transverse polarization of [Formula: see text] and [Formula: see text] hyperons has been measured in inclusive quasireal photoproduction process for various target nuclei. The polarization observed is positive for light target nuclei and compartaible with zero for heavy target nuclei.

The Design of a Portable Instrument for Straightness Measurement of Large Machine Tool

The paper inctroduces the guide for the design of a portable instrument for straightness measurement of large machine tool. the measuring instrument is designed with two-quadrant photocell which is used as the position sensor, single-chip for the processor is MSP430F427 which have LCD driver circuit, the instrument is charged by lithium battery-powered. Its size is small, no external connection when it is used, data acquisition, processing and error displayed can be done in the part of light target. It have the advantage of convenience, simple and high measurement accuracy when it is used.

ALPHA SPECTROSCOPIC FACTOR OF 16O FROM ITS BREAKUP USING CONTINUUM DISCRETIZED COUPLED CHANNEL (CDCC) METHOD

In this work we extract the alpha spectroscopic factor ( S α) of 16 O ground state from breakup reaction. The CDCC theory is used to extract S α by comparison with 16 O breakup data from a light target (27 Al ). Extracted values show a small dependence on the single particle binding potential of 16 O at forward angles. At incident energies between 72 to 125 MeV S α varies from 2.29-2.83 (Wood Saxon binding potential) and between 2.42-3.72 (Gaussian potential).

PHOTOPRODUCTION OF MESONS OFF LIGHT NUCLEI

During the last few years photoproduction of mesons off light target nuclei (2 H , 3 He , 7 Li ) has been systematically studied at the tagged photon beams of the Bonn ELSA accelerator and the Mainz MAMI accelerator. The experiments used the combined Crystal Barrel/TAPS setup in Bonn and the Crystal Ball/TAPS setup in Mainz. Most measurements investigated meson photoproduction off the neutron for many different reaction channels in order to establish the iso-spin structure of electromagnetic resonance couplings. This project used mostly deuteron targets. The measurements with the He and Li targets aimed at the search for η-mesic nuclei and hadron in-medium properties.

CENTRAL COLLISIONS INDUCED BY LIGHT TARGET NUCLEI

For the interactions of p, 3 He , 4 He , and 6 Li with emulsion at 4.5 A GeV/c, an experimental study has been performed. The type of interactions chosen was central, which enables to analyze a specific interaction mechanism. The selection of the central events has been in the framework of the particles emitted beyond the kinematic limits (θ Lab ≥90°). This selection provides a strict criterion to distinguish the central collisions. For the sake of comparison, an additional criterion is introduced. It deals with interactions that exhibit an absence of projectile fragmentation. A detailed study of the emitted pions multiplicity is presented. The focusing is on the light emulsion target H and CNO in comparison with the heavy AgBr . The analysis reveals that the occultation of light projectile nuclei is possible in CNO targets along with the complete occultation in AgBr .