High Energy collisions of nuclei usually lead to the emission of evaporation neutrons from both “beam” and “target” nuclei. At the RHIC heavy ion collider with 100GeV/u beam energy, evaporation neutrons diverge by less than 2 milliradians from the beam axis. Neutral beam fragments can be detected downstream of RHIC ion collisions (and a large aperture Accelerator dipole magnet) if θ ≤ 4 mr but ...

It is usually assumed in stellar nucleosynthesis calculations that neutrons art completely thcrmalizcd. Hence, if the cross section of a neutron-induced reaction has a threshold, or it is suppressed by the Coulomb barrier in the exit channel, the reaction rate is quite low. However, the contribution front the decelerating fast neutrons has been neglected previously. We show that, though ihe fra...

background: polyethylene composites including boron can be used as an effective neutron shield. our investigation focuses on manufacturing borated polyethylene nano-composite. the purpose of this study is to design a radiation shield for use in both neutron and gamma fields. materials and methods: borated polyethylene shields containing 2%, and 5% weight percentage of boron nano-particles were ...

background: a boron neutron capture therapy (bnct) facility, based on a dt neutron generator, with the final goal to find out a potential, alternative, solution to existing bnct treatment facilities which are based on nuclear reactors is examined. materials and methods: with the aim of the mcnp4b monte carlo code different beam-shaping assembly (bsa) configurations were considered. lead was sel...

Standard GRB fireballs must carry free neutrons. This crucially changes the mechanism of fireball deceleration by an external medium. As the ion fireball decelerates, the coasting neutrons form a leading front. They gradually decay, leaving behind a relativistic trail of decay products mixed with the ambient medium. The ion fireball sweeps up the trail and drives a shock wave in it. Thus, obser...

We measured the first azimuthal distributions of triple–differential cross sections of neutrons emitted in heavy-ion collisions, and compared their maximum azimuthal anisotropy ratios with Boltzmann–Uehling–Uhlenbeck (BUU) calculations with a momentum-dependent interaction. The BUU calculations agree with the tripleand double-differential cross sections for positive rapidity neutrons emitted at...

Relativistic neutron-loaded outflows in gamma-ray bursts are studied at their early stages, before deceleration by a surrounding medium. The outflow has four components: radiation, electrons, protons and neutrons. The components interact with each other and exchange energy as the outflow expands. The presence of neutrons significantly changes the outflow evolution. Before neutrons decouple from...

X-ray imaging instruments will operate in a harsh ionizing radiation background environment on implosion experiments at the National Ignition Facility. These backgrounds consist of mostly neutrons and gamma rays produced by inelastic scattering of neutrons. Imaging systems based on x-ray framing cameras with film and CCD’s have been designed to operate in such harsh neutron-induced background e...

Boron Neutron Capture Therapy (BNCT) can be performed at a facility with a nuclear reactor or at hospitals that have developed alternative neutron sources. A beam of epithermal neutrons penetrates the brain tissue, reaching the malignancy. Once there the epithermal neutrons slow down and these low-energy neutrons combine with boron 10 (delivered beforehand to the cancer cells by drugs or antibo...

The general theory of neutron scattering is presented, valid for the whole domain of slow neutrons from thermal to ultracold. Particular attention is given to multiple scattering which is the dominant process for ultracold neutrons (UCN). For thermal and cold neutrons, when the multiple scattering in the target can be neglected, the cross section is reduced to the known value. A new expression ...