42 research outputs found
Target Optimisation Studies for Surface Muon Production
The current paper discusses possible designs for a stand alone muon target for MuSR studies of condensed matter science. Considering the ISIS 7 mm graphite target as a reference, Geant4 simulations have been performed in order to optimize the target parameters with respect to muon and pion yield. Previous studies suggested that the muon production can be optimized by using a thin graphite slab target with an incident proton energy significantly lower than initially considered. Surface muon production obtained by firing an 800 MeV proton beam energy onto the target is simulated and potential improvements to the target material, geometry and angle orientation with respect to the incoming proton beam as well as an estimated performance of the muon target are presented in this paper. Implications for the ISIS muon facility are also discussed. A comparison of the pion production cross section between experimental data and three theoretical models for the latest four Geant4 versions is also included in this paper
GEANT4 Target Simulations for Low Energy Medical Applications
The GEANT4 code offers an extensive set of hadronic models for various projectiles and energy ranges. These models include theoretical, parameterized and, for low energy neutrons, data driven models. Theoretical or semi-empirical models sometimes cannot reproduce experimental data at low energies(<100MeV), especially for low Z elements, and therefore recent GEANT4 developments included a new particle\hp package which uses evaluated nuclear databases for proton interactions below 200 MeV. These recent developments have been used to study target designs for low energy proton accelerators, as replacements of research reactors, for medical applications. Presented in this paper are results of benchmarking of these new models for a range of targets, from lithium neutron production targets to molybdenum isotope production targets, with experimental data. Also included is a discussion of the most promising target designs that have currently been studied
5MW Power Upgrade Studies of the ISIS TS1 Target
The increasing demand for neutron production at the ISIS neutron spallation source has motivated a study of an upgrade of the production target TS1. This study focuses on a 5 MW power upgrade and complete redesign of the ISIS TS1 spallation target, reflector and neutron moderators. The optimisation of the target-moderator arrangement was done in order to obtain the maximum neutron output per unit input power. In addition, at each step of this optimisation study, the heat load and thermal stresses were calculated to ensure the target can sustain the increase in the beam power
GEANT4 Simulations of Proton-Induced Spallation for Applications in ADSR Systems
In order to assess the feasibility of spallation driven fission and transmutation, we have simulated proton induced neutron production using GEANT4, initially benchmarking our simulations against published experimental neutron spectra produced from a thick lead target bombarded with 0.5 and 1.5 GeV protons. The Bertini and INCL models available in GEANT4, coupled with the high precision (HP) neutron model, are found to adequately reproduce the published experimental data. Given the confidence in the GEANT4 simulations provided by this benchmarking, we have then proceeded to simulate neutron production as a function of target geometry and thence to some preliminary studies of neutron production in an ADSR with the geometry similar to that of the proposed Belgian MYRRHA project. This paper presents the results of our GEANT4 benchmarking and simulations
Simulations of Muon production targets
We review the recent simulations of muon production targets using the GEANT4 framework. Options for modifying the ISIS target are considered, as well as a wider study considering different materials, geometries and incident beam energies
GEANT4 Studies of Magnets Activation in the HEBT Line for the European Spallation Source
The High Energy Beam Transport (HEBT) line for the European Spallation Source is designed to transport the beam from the underground linac to the target at the surface level while keeping the beam losses small and providing the requested beam footprint and profile on the target. This paper presents activation studies of the magnets in the HEBT line due to backscattered neutrons from the target and beam interactions inside the collimators producing unstable isotopes
Induced activation in accelerator components
The residual activity induced in particle accelerators is a serious issue from the point of view of radiation safety as the long-lived radionuclides produced by fast or moderated neutrons and impact protons cause problems of radiation exposure for staff involved in the maintenance work and when decommissioning the facility. This paper presents activation studies of the magnets and collimators in the High Energy Beam Transport line of the European Spallation Source due to the backscattered neutrons from the target and also due to the direct proton interactions and their secondaries. An estimate of the radionuclide inventory and induced activation are predicted using the GEANT4 code
Neutron Spallation Studies for an Accelerator Driven Subcritical Reactor
NuÂcleÂar power proÂducÂtion can benÂeÂfit from the deÂvelÂopÂment of more comÂpreÂhenÂsive alÂterÂnaÂtives for dealÂing with long-term raÂdioacÂtive waste. One such alÂterÂnaÂtive is an acÂcelÂerÂaÂtor-drivÂen subÂcritÂiÂcal reÂacÂtor (ADSR) which has been proÂposed for both enÂerÂgy proÂducÂtion and for burnÂing raÂdioacÂtive waste. Here we inÂvesÂtiÂgate the efÂfects of the size of the ADSR spalÂlaÂtion tarÂget on the total neuÂtron yield inÂteÂgratÂed over the neuÂtron enÂerÂgy and emisÂsion angle. The conÂtriÂbuÂtion to the total neuÂtron yield from the (n, xn) neuÂtron inÂterÂacÂtions is evalÂuÂatÂed at proÂton beam enÂerÂgies beÂtween 0.4 and 2 GeV. CalÂcuÂlaÂtions have been carÂried out with the GEANÂT4 simÂuÂlaÂtion code using the Liege inÂtranuÂcleÂar casÂcade model and the reÂsults are comÂpared to the the LAHET/MCNP code packÂage preÂdicÂtions
Impact of the Energy of the Proton Driver on Muon Production
Simulations studies have been carried out to examine the
impact of the energy of the proton driver on muon production.
The muon flux is calculated as a function of proton
energy over a wide range, which covers the energies at the
existing muon and neutron facilities worldwide. The muon
and higher energy pion yields are normalised per beam current
and accelerator power. The case of a higher energy of
the proton driver at the ISIS muon facility is also examined
Material Studies for the ISIS Muon Target
The ISIS neutron spallation source uses a separate muon
target 20 m upstream of the neutron target for MuSR research.
Because ISIS is primarily a neutron source, it imposes
restrictions upon the muon target, which normally
are not present at other muon facilities like PSI or TRIUMF.
In particular it is not possible to use thicker targets
and higher energy proton drivers because of the loss of neutrons
and the increased background at neutron instruments.
In this paper we investigate possible material choices for
the ISIS muon target for increased muon yield