Towards a relational geography of disability

In this paper we develop linkages between non-representational theory and emerging work by disability scholars in geography. We argue that non-representational thinking has the potential to advance our understanding of the complex and emergent geographies of dis/ability. We first outline key dimensions of non-representational thinking within geography. We then explore how this perspective has begun to, and might further inform, geographical scholarship on disability. Next, we extend our thinking to consider how NRT might provide the basis for a critical geography of the ‘able-body’. We conclude by reflecting on the conceptual, political, methodological and empirical implications of our argument

Performance evaluation of the Boron Coated Straws detector with Geant4

The last decade has witnessed the development of several alternative neutron detector technologies, as a consequence of upcoming neutron sources and upgrades, as well the world-wide shortage of $^3$He. One branch of development is the family of $^{10}$B-based gaseous detectors. This work focuses on the boron coated straws (BCS) by Proportional Technologies Inc., a commercial solution designed for use in homeland security and neutron science. A detailed Geant4 simulation study of the BCS is presented, which investigates various aspects of the detector performance, e.g. efficiency, activation, absorption and the impact of scattering on the measured signal. The suitability of the BCS detector for Small Angle Neutron Scattering (SANS), direct chopper spectrometry and imaging is discussed.Comment: 50 pages, 37 figures, minor changes after review, results unchange

One-ended subgroups of graphs of free groups with cyclic edge groups

Consider a one-ended word-hyperbolic group. If it is the fundamental group of a graph of free groups with cyclic edge groups then either it is the fundamental group of a surface or it contains a finitely generated one-ended subgroup of infinite index. As a corollary, the same holds for limit groups. We also obtain a characterisation of surfaces with boundary among free groups equipped with peripheral structures.Comment: 22 pages, 3 figures, corrected typos in the introductio

Residually free 3-manifolds

We classify those compact 3-manifolds with incompressible toral boundary whose fundamental groups are residually free. For example, if such a manifold $M$ is prime and orientable and the fundamental group of $M$ is non-trivial then $M \cong \Sigma\times S^1$, where $\Sigma$ is a surface.Comment: 19 pages, referee's comments incorporated, to appear in Algebraic & Geometric Topolog

Suppression of intrinsic neutron background in the Multi-Grid detector

One of the key requirements for neutron scattering instruments is the Signal-to-Background ratio (SBR). This is as well a design driving requirement for many instruments at the European Spallation Source (ESS), which aspires to be the brightest neutron source of the world. The SBR can be effectively improved with background reduction. The Multi-Grid, a large-area thermal neutron detector with a solid boron carbide converter, is a novel solution for chopper spectrometers. This detector will be installed for the three prospective chopper spectrometers at the ESS. As the Multi-Grid detector is a large area detector with a complex structure, its intrinsic background and its suppression via advanced shielding design should be investigated in its complexity, as it cannot be naively calculated. The intrinsic scattered neutron background and its effect on the SBR is determined via a detailed Monte Carlo simulation for the Multi-Grid detector module, designed for the CSPEC instrument at the ESS. The impact of the detector vessel and the neutron entrance window on scattering is determined, revealing the importance of an optimised internal detector shielding. The background-reducing capacity of common shielding geometries, like side-shielding and end-shielding is determined by using perfect absorber as shielding material, and common shielding materials, like B$_{4}$C and Cd are also tested. On the basis of the comparison of the effectiveness of the different shielding topologies and materials, recommendations are given for a combined shielding of the Multi-Grid detector module, optimised for increased SBR.Comment: 26 pages, 18 figures, revise

Geant4 based simulations for novel neutron detector development

A Geant4-based Python/C++ simulation and coding framework, which has been developed and used in order to aid the R&D efforts for thermal neutron detectors at neutron scattering facilities, is described. Built upon configurable geometry and generator modules, it integrates a general purpose object oriented output file format with meta-data, developed in order to facilitate a faster turn-around time when setting up and analysing simulations. Also discussed are the extensions to Geant4 which have been implemented in order to include the effects of low-energy phenomena such as Bragg diffraction in the polycrystalline support materials of the detector. Finally, an example application of the framework is briefly shown.Comment: Proceedings for the 20th International Conference on Computing in High Energy and Nuclear Physics (CHEP

Prospects in MPGDs development for neutron detection

Compared to Multi Wires Proportional Chambers (MWPC), Micro-Pattern Gas Detectors (MPGD) used in HEP to detect MIPs offer better spatial resolution, counting rate capability, and radiation hardness; their fabrication is also more reproducible. Provided similar advantages are applicable to detect neutrons, MPGDs might contribute significantly to the development of neutron scientific instrumentation. In order to evaluate the prospects of neutron MPGDs, it is worth knowing the applications which would benefit from a gain in performance, and if they offer a competitive alternative to conventional 3He detectors. These questions have been at the focus of the workshop "Neutron Detection with Micro-Pattern Gaseous Detectors" organized by RD51 in collaboration with HEPTech, which took place at CERN on October 14-15, 2013. The goal of this workshop was to help disseminating MPGD technologies beyond High Energy Physics, and to give the possibility to academic institutions, potential users and industry to meet together. This summary article starts with a short summary of the state of the art of MPGD techniques for HEP; then specificities in the design of neutron detector are described; the consequence of the 3He shortage are briefly discussed; requirements for neutron scattering science at current facilities and at the future ESS are described; finally, we give some recommendations about possible directions where we believe the development of neutron MPGDs is of particular interest for possible use on neutron scattering instruments.Comment: Summary based on presentations during RD51 Academia-Industry Matching Event, CERN October 14-15, 201

Recommended Locations of Beam Loss Monitors for the ATLAS Roman Pots

This note suggests suitable locations to position beam loss monitors to observe losses on the ATLAS Roman Pot station located close to 240m from IP1. This monitoring is envisaged to help to avoid quenches of the super- conducting magnets downstream of the roman pots and to avert damage to either the LHC machine elements or the roman pot detectors. The results presented in this note indicate the locations where the BLMs should be installed. The recommended locations are determined using previous simulation results on BLM response to losses; therefore these results should be considered in conjunction with the previous results. A more detailed note on the topic will follow later

Recommended Locations of Beam Loss Monitors for the TOTEM Roman Pots

This note presents results from simulations of losses on the TOTEM Roman Pot stations located close to 150m and 220m from IP5. These results are used to evaluate suitable locations to position beam loss monitors to monitor these losses, and help to avoid quenches of the super-conducting magnets downstream of the roman pots. The results presented in this note indicate the locations where the BLMs should be installed. A more detailed note on the topic will follow later