All-loop calculations of total, elastic and single diffractive cross sections in RFT via the stochastic approach

We apply the stochastic approach to the calculation of the Reggeon Field Theory (RFT) elastic amplitude and its single diffractive cut. The results for the total, elastic and single difractive cross sections with account of all Pomeron loops are obtained.Comment: 4 pages, 3 figures; prepared for the proceedings of the workshop 'Diffraction-2012', Puerto del Carmen, Lanzarote, September 10 - 15, 201

Coherent medium-induced gluon radiation in hard forward 1→11\to 1 partonic processes

We revisit the medium-induced coherent radiation associated to hard and forward (small angle) scattering of an energetic parton through a nuclear medium. We consider all $1\to 1$ hard forward processes ($g \to g$, $q \to q$, $q \to g$ and $g \to q$), and derive the energy spectrum of induced coherent radiation rigorously to all orders in the opacity expansion and for the specific case of a Coulomb scattering potential. We obtain a simple general formula for the induced coherent spectrum, which encompasses the results corresponding to previously known special cases.Comment: 35 pages, 10 figures; title changed, introduction developed and references added, detailed discussion added in Section VI, all results unchanged; version v2 corresponds to the published versio

Neutron absorption in supermirror coatings: Effects on shielding

The quantification of the dose rate and the composition of the dose in the vicinity of supermirror coated guides is essential for designing shielding for beamlines transporting neutrons with a high flux. We present results on a calculation of radiative neutron absorption in Ni/Ti and NiMo/Ti supermirror coatings which leads to the emission of high energy gamma rays. A simple parameterization of the absorption probability in the coating materials per incident neutron is given as a function of momentum transfer at reflection

Beamline Simulation for the NNBAR Experiment at the European Spallation Source

The HIBEAM and NNBAR experiments are a proposed fundamental science experiments at the European Spallation Source, performing high precision searches for neutron conversions in several baryon number violating (BNV) channels. For simulations of the NNBAR beamline, a new sampling method has been developed. The method is based on probability density evaluation and duct source biasing and enables the simulations of the entire NNBAR beamline with high statistics while also preserving correlations of the neutron tracks

McStas and Scatter Logger driven calculations of prompt gamma shielding for neutron guides

McStas ScatterLogger component bundle was adapted for evaluating a contribution to dose rate around neutron guides arising from prompt gamma radiation accompanying neutron capture in the supermirror guide coating upon specular reflection. Thickness of typical shielding materials needed to reduce this contribution to the desired level can be now evaluated directly from running a ray-tracing simulation of the instrument in McStas. An overview of the corresponding modifications to the existing McStas components and description of the newly written supplementary ones is given together with examples and use instructions.publishedVersio