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Marc Timmins

Publications and source records attributed to Marc Timmins.

2 recordsLinked to original sources

Introduction to the Mechanical Design of Accelerators

Particle accelerators represent some of the most sophisticated engineering achievements of our time. Their construction requires a unique combination of physics insight and mechanical engineering expertise. The aim of this paper is to provide young mechanical engineers with an introduction to the principles, methods, and challenges associated with the mechanical design of accelerators. The lecture upon which this proceeding is based emphasized the translation of functional requirements into engineering specifications, the critical importance of robust and reliable design, and the need for precisely defined drawings supported by international standards such as ISO GPS and GD&T. Through illustrative examples and a practical case inspired by CERN's existing components, the paper underlines the necessity of anticipating lifecycle demands, ensuring manufacturability, and safeguarding operational reliability. Particular emphasis is placed on the contractual value of 2D drawings, the practical application of functional dimensioning, and tolerance chain analysis. By reviewing common pitfalls and exploring best practices, the paper seeks to orient engineers towards design choices that balance cost, reliability, and performance.

physics.acc-ph

Design of the third-generation lead-based neutron spallation target for the neutron time-of-flight facility at CERN

The neutron time-of-flight (n_TOF) facility at the European Laboratory for Particle Physics (CERN) is a pulsed white-spectrum neutron spallation source producing neutrons for two experimental areas: the Experimental Area 1 (EAR1), located 185 m horizontally from the target, and the Experimental Area 2 (EAR2), located 20 m above the target. The target, based on pure lead, is impacted by a high-intensity 20-GeV/c pulsed proton beam. The facility was conceived to study neutron-nucleus interactions for neutron kinetic energies between a few meV to several GeV, with applications of interest for nuclear astrophysics, nuclear technology, and medical research. After the second-generation target reached the end of its lifetime, the facility underwent a major upgrade during CERN's Long Shutdown 2 (LS2, 2019-2021), which included the installation of the new third-generation neutron target. The first and second-generation targets were based on water-cooled massive lead blocks and were designed focusing on EAR1, since EAR2 was built later. The new target is cooled by nitrogen gas to avoid erosion-corrosion and contamination of cooling water with radioactive lead spallation products. Moreover, the new design is optimized also for the vertical flight path and EAR2. This paper presents an overview of the target design focused on both physics and thermo-mechanical performance, and includes a description of the nitrogen cooling circuit and radiation protection studies.

physics.ins-det