673,142 research outputs found
Simulation and Efficiency Studies of Optical Photon Transportation and Detection with Plastic Antineutrino Detector Modules
In this work, the simulation of optical photons is carried out in an
antineutrino detector module consisting of a plastic scintillator connected to
light guides and photomultipliers on both ends, which is considered to be used
for remote reactor monitoring in the field of nuclear safety. Using Monte Carlo
(MC) based GEANT4 simulation, numerous parameters influencing the light
collection and thereby the energy resolution of the antineutrino detector
module are studied: e.g., degrees of scintillator surface roughness, reflector
type, and its ap- plying method onto scintillator and light guide surface, the
reflectivity of the reflector, light guide geometries and diameter of the
photocathode. The impact of each parameter is inves- tigated by looking at the
detected spectrum, i.e. the number photoelectrons per depositing energy. In
addition, the average light collection efficiency of the detector module and
its spatial variation are calculated for each simulation setup. According to
the simulation re- sults, it is found that photocathode size, light guide
shape, reflectivity of reflecting material and wrapping method show a
significant impact on the light collection efficiency while scin- tillator
surface polishing level and the choose of reflector type show relatively less
impact. This study demonstrates that these parameters are very important in the
design of plastic scintillator included antineutrino detectors to improve the
energy resolution efficiency
Simulation of waviness in neutron guides
As the trend of neutron guide designs points towards longer and more complex
guides, imperfections such as waviness becomes increasingly important.
Simulations of guide waviness has so far been limited by a lack of reasonable
waviness models. We here present a stochastic description of waviness and its
implementation in the McStas simulation package. The effect of this new
implementation is compared to the guide simulations without waviness and the
simple, yet unphysical, waviness model implemented in McStas 1.12c and 2.0
Study of heat and mass transfer applications in the field of engineering by using OpenFOAM
The aim of the project is to study OpenFOAM software and establish a well-based guide of standard and complex heat and mass transfer applications in engineering. OpenFOAM is a free, open source CFD software package. By being open, OpenFOAM offers users complete freedom to customise and extend its existing functionality. On the other hand, OpenFOAM offers a quick start user guide and there also is little available documentation and several examples. Thus, the project intends to: - Prepare an introductory and complete user guide to OpenFOAM with solved standard heat and mass transfer applications to the beginners, specially bachelor students ‐ Numerical simulation of complex heat and mass transfer applications in engineering with OpenFOAM in two‐ and three‐dimensional problems ‐ Practice in developing engineering projects by combining technical work with economic and environmental aspectsThe main tasks to be carried out in this project will be to: - Edit problems solved with OpenFOAM including explanations and detailed considerations in order to prepare a guide for new learners, specially bachelor students - Work in the study and analysis of heat and mass transfer simulations involving real engineering problems - Determine feasibility of the engineering project to be carried out - Study the socio-economics aspects in fluid dynamics applications solved by numerical simulation and fields of interest - Results analysi
The numerical simulation tool for the MAORY multiconjugate adaptive optics system
The Multiconjugate Adaptive Optics RelaY (MAORY) is and Adaptive Optics
module to be mounted on the ESO European-Extremely Large Telescope (E-ELT). It
is a hybrid Natural and Laser Guide System that will perform the correction of
the atmospheric turbulence volume above the telescope feeding the Multi-AO
Imaging Camera for Deep Observations Near Infrared spectro-imager (MICADO). We
developed an end-to-end Monte- Carlo adaptive optics simulation tool to
investigate the performance of a the MAORY and the calibration, acquisition,
operation strategies. MAORY will implement Multiconjugate Adaptive Optics
combining Laser Guide Stars (LGS) and Natural Guide Stars (NGS) measurements.
The simulation tool implements the various aspect of the MAORY in an end to end
fashion. The code has been developed using IDL and uses libraries in C++ and
CUDA for efficiency improvements. Here we recall the code architecture, we
describe the modeled instrument components and the control strategies
implemented in the code.Comment: 6 pages, 1 figure, Proceeding 9909 310 of the conference SPIE
Astronomical Telescopes + Instrumentation 2016, 26 June 1 July 2016
Edinburgh, Scotland, U
USERS' GUIDE TO THE MINNESOTA REGIONAL DEVELOPMENT SIMULATION LABORATORY
This manual is a users' guide to the Minnesota Regional Development Simulation Laboratory, called SIMLAB.Community/Rural/Urban Development,
Stacked Thompson Bandits
We introduce Stacked Thompson Bandits (STB) for efficiently generating plans
that are likely to satisfy a given bounded temporal logic requirement. STB uses
a simulation for evaluation of plans, and takes a Bayesian approach to using
the resulting information to guide its search. In particular, we show that
stacking multiarmed bandits and using Thompson sampling to guide the action
selection process for each bandit enables STB to generate plans that satisfy
requirements with a high probability while only searching a fraction of the
search space.Comment: Accepted at SEsCPS @ ICSE 201
Impact of Sodium Layer variations on the performance of the E-ELT MCAO module
Multi-Conjugate Adaptive Optics systems based on sodium Laser Guide Stars may
exploit Natural Guide Stars to solve intrinsic limitations of artificial
beacons (tip-tilt indetermination and anisoplanatism) and to mitigate the
impact of the sodium layer structure and variability. The sodium layer may also
have transverse structures leading to differential effects among Laser Guide
Stars. Starting from the analysis of the input perturbations related to the
Sodium Layer variability, modeled directly on measured sodium layer profiles,
we analyze, through a simplified end-to-end simulation code, the impact of the
low/medium orders induced on global performance of the European Extremely Large
Telescope Multi-Conjugate Adaptive Optics module MAORY.Comment: 7 pages, 5 figures, SPIE conference Proceedin
End to end numerical simulations of the MAORY multiconjugate adaptive optics system
MAORY is the adaptive optics module of the E-ELT that will feed the MICADO
imaging camera through a gravity invariant exit port. MAORY has been foreseen
to implement MCAO correction through three high order deformable mirrors driven
by the reference signals of six Laser Guide Stars (LGSs) feeding as many
Shack-Hartmann Wavefront Sensors. A three Natural Guide Stars (NGSs) system
will provide the low order correction. We develop a code for the end-to-end
simulation of the MAORY adaptive optics (AO) system in order to obtain
high-delity modeling of the system performance. It is based on the IDL language
and makes extensively uses of the GPUs. Here we present the architecture of the
simulation tool and its achieved and expected performance.Comment: 8 pages, 4 figures, presented at SPIE Astronomical Telescopes +
Instrumentation 2014 in Montr\'eal, Quebec, Canada, with number 9148-25
Evaporative cooling of an atomic beam
We present a theoretical analysis of the evaporative cooling of an atomic
beam propagating in a magnetic guide. Cooling is provided by transverse
evaporation. The atomic dynamics inside the guide is analyzed by solving the
Boltzmann equation with two different approaches: an approximate analytical
ansatz and a Monte-Carlo simulation. Within their domain of validity, these two
methods are found to be in very good agreement with each other. They allow us
to determine how the phase-space density and the flux of the beam vary along
its direction of propagation. We find a significant increase for the
phase-space density along the guide for realistic experimental parameters. By
extrapolation, we estimate the length of the beam needed to reach quantum
degeneracy.Comment: 13 pages, 7 figures, to be published in EPJ D, revised versio
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