Neutron Position Sensitive Detectors for the ESS

The European Spallation Source (ESS) in Lund, Sweden will become the world's leading neutron source for the study of materials. The instruments are being selected from conceptual proposals submitted by groups from around Europe. These instruments present numerous challenges for detector technology in the absence of the availability of Helium-3, which is the default choice for detectors for instruments built until today and due to the extreme rates expected across the ESS instrument suite. Additionally a new generation of source requires a new generation of detector technologies to fully exploit the opportunities that this source provides. The detectors will be sourced from partners across Europe through numerous in-kind arrangements; a process that is somewhat novel for the neutron scattering community. This contribution presents briefly the current status of detectors for the ESS, and outlines the timeline to completion. For a conjectured instrument suite based upon instruments recommended for construction, a recently updated snapshot of the current expected detector requirements is presented. A strategy outline as to how these requirements might be tackled by novel detector developments is shown. In terms of future developments for the neutron community, synergies should be sought with other disciples, as recognized by various recent initiatives in Europe, in the context of the fundamentally multi-disciplinary nature of detectors. This strategy has at its basis the in-kind and collaborative partnerships necessary to be able to produce optimally performant detectors that allow the ESS instruments to be world-leading. This foresees and encourages a high level of collaboration and interdependence at its core, and rather than each group being all-rounders in every technology, the further development of centres of excellence across Europe for particular technologies and niches.Comment: 8 pages, 1 figure. Proceedings from the 23rd International Workshop on Vertex Detectors, 15-19 September 2014, Macha Lake, The Czech Republic. PoS(Vertex2014)02

Evolution control for software product lines: An automation layer over configuration management

Modern software organizations increasingly aim at the development of individualized customer solutions in a cost-effective way. Product line engineering is a paradigm on the rise that addresses this goal and achieves true order of magnitude improvements in efficiency, quality and time-to-market. In order to achieve these improvements product line engineering builds on strategic software reuse. In this regard the development lifecycle is decomposed in two major parallel running activities: family and application engineering. The former develops software assets for reuse across the product line while the latter applies reusable assets in the context of particular products. In order to keep the evolution of a product line under control family and application engineering must be continuously coordinated. Software Configuration Management (SCM) is an established and mature technology for evolution control of software systems. However traditional SCM does not address explicitly the particular needs of product line engineering. When a product line evolves the number of product line members and variations increase significantly. In terms of scalability SCM systems can deal with the increased complexity. However, the execution of multiple configuration management operations becomes necessary in order to carry out evolution control scenarios within a product line. Therefore, users of SCM systems can easily get overwhelmed while trying to make use of SCM mechanisms in order to keep product line evolution under control. In this context a serious amount of effort is often spent in practice to synchronize changes between family and application engineering. In some cases the synchronization is even neglected as the additional burden is not bearable. This in turn leads to unnecessary duplication of work and other serious problems. In the long term an organization possibly faces significant deficiencies in the timely delivery of software products. Overall problem addressed by this thesis is that software configuration management requires significant effort, when used for the coordination of product line engineering processes. Main Goal of this thesis is to reduce the software configuration management effort for the coordination of product line engineering processes. This thesis introduces a virtual layer - called Customization Layer in the following - that bridges the gap between product line engineering and SCM. The layer offers a set of specialized evolution control operations for product lines, while conventional SCM operations are used behind the scenes and in an automated way. The idea of the Customization Layer is accompanied by a method that enables the specification of the product line at hand and the selection of the necessary evolution control scenarios. Subsequently the method provides guidelines for the implementation of the scenarios based on the configuration management system available within an organization. The approach has been validated through structural and usability evaluation, experimental studies as well as partially through a case study with an industrial organization. The results have shown potential for significant improvements in terms of efficiency and effectiveness of evolution control

Study and application of micrometric alignment on the prototype girders of the CLIC Two-Beam Module

The Compact LInear Collider (CLIC), currently under study at CERN, aims at the development of a Multi-TeV e+ e- collider. The micro-precision CLIC RF-structures will have an accelerating gradient of 100 MV/m and will be mounted and aligned on specially developed supporting girders. The girder fabrication constraints are dictated by stringent physics requirements. The micrometric pre-alignment over several kilometers of girders, allow for the CLIC structures to fulfill their acceleration and collision functionality. Study of such girders and their sophisticated alignment method, is a challenging case involving dedicated mechanical design as well as prototype production and experimental testing

Design and Study on a 5 Degree-of-freedom Adjustment Platform for CLIC Drive Beam Quadrupoles

Since several years CERN is studying the feasibility of building a high energy e⁺ e^{−} linear collider: the CLIC (Compact LInear Collider). The pre-alignment precision and accuracy requirement for the transverse positions of the linac components is typically 14 micrometers over a sliding window of 200m. One of the challenges is precise adjustment of Drive Beam quadrupole’s magnetic axis. It has to be done with micrometric resolution along 5 DOF in a common support’s coordinate system. This paper describes the design and the study of a solution based on flexural components in a type of “Stewart Platform” configuration. The engineering approach, the lessons learned (“know how”), the issues of adjustment solution and the mechanical components behaviors are presented

Determination of the Magnetic Axis of a CLIC Drive Beam Quadrupole with respect to External Alignment Targets using a Combination of WPS, CMM and Laser Tracker Measurements

CERN is currently studying the feasibility of building a high energy e⁺ e^{−} linear collider: the CLIC (Compact LInear Collider). One of the engineering challenges is the pre-alignment precision and accuracy requirement on the alignment of the linac components. For example, the magnetic axis of a Drive Beam Quadrupole will need to be aligned within 20 um rms with respect to a straight reference line of alignment. The fiducialisation process which is the determination of the magnetic axis with respect to external alignment targets, that is part of this error budget, will have to be performed at an accuracy never reached before. This paper presents the strategy proposed for the fiducialisation of the Drive Beam quadrupole, based on a combination of CMM measurements, WPS measurements and Laser tracker measurements. The results obtained on a dedicated test bench will be described as well