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As part of the engineering validation and engineering design activities (EVEDA) phase for the international fusion materials irradiation facility IFMIF, major elements of a lithium target facility and the test facility were designed, prototyped and validated. For the lithium target facility, the EVEDA lithium test loop was built at JAEA and used to test the stability (waves and long term) of the lithium flow in the target, work out the startup procedures, and test lithium purification and analysis. It was confirmed by experiments in the Lifus 6 plant at ENEA that lithium corrosion on ferritic martensitic steels is acceptably low. Furthermore, complex remote handling procedures for the remote maintenance of the target in the test cell environment were successfully practiced. For the test facility, two variants of a high flux test module were prototyped and tested in helium loops, demonstrating their good capabilities of maintaining the material specimens at the desired temperature with a low temperature spread. Irradiation tests were performed for heated specimen capsules and irradiation instrumentation in the BR2 reactor at SCK-CEN. The small specimen test technique, essential for obtaining material test results with limited irradiation volume, was advanced by evaluating specimen shape and test technique influences.

The LHC machine is composed of arcs and insertion regions where superconducting magnets, working at temperatures of 1.9 K and 4.5 K, have flexibly interconnected beam vacuum chambers. These interconnects must respect strict requirements in terms of impedance, aperture, space optimization and reliability. A complete interconnect design was first developed for the arc regions, and from which a total of 20 variants have been created according to the different functional requirements of each pair of cryostats along the machine. All design features and manufacture processes were validated through extensive testing. Manufacture and assembly cost was minimised by using a modular interconnect design, with common components shared among different design variants. A detailed quality assurance structure was implemented in order to achieve the high level of reliability required. This paper presents the layout of cold beam vacuum interconnects along with details of development and testing performed to validate design and integration.

The Large Hadron Collider (LHC), the next accelerator being constructed on the CERN site, will accelerate and collide 7 TeV protons and heavier ions up to lead. More than 1700 cryomagnets working at 1.9 or 4.5 k will form part of the magnetic lattice of the LHC. The beam pipe passage from cryogenic temperatures to room temperature zones will be achieved by 200 cold to warm transitions (CWTs). The CWTs will compensate for longitudinal and transversal displacements between beam screens and cold bores, ensuring vacuum continuity without limiting the aperture for the beam. The transverse impedance contribution is kept below the assigned total budget of 1 MO/m by means of a 4 µm thick Cu coating that also minimises the dynamic heat load through image currents. Tests have been performed that confirm that the static heat load per CWT to the cryomagnets remains below 2.5 W, hence validating the design.

The history of particle colliders begins in the early 60's when an idea previously patented by R. Wideroe in 1953 is constructed. The design of the vacuum chamber in their experimental area became essential as it was the rst physical barrier that the particles to be detected needed to traverse. The interaction of the products of the collisions with the vacuum chamber structural materials, hindered the identification of the significative events. This Thesis analyses the historical evolution of the experimental vacuum chambers and summarizes the technical criteria that are to be fulfilled. The Large Hadron Collider (LHC) presently under construction at CERN is the last generation of particle colliders. Four big experiments will be in operation (ATLAS, CMS, ALICE and LHCb) in the LHC with diferent physics objectives. In particular, LHCb will be devoted to the study of CP violation and the design of its vacuum chamber is the scope of this Thesis. Physics simulations with an initial design consisting of a conical aluminium vacuum chamber with stainless steel flanges and bellows expansion joints, foresaw redundancies in the experiment detection channels that would make it inefficient. The reduction of the radiation background generated after the interactions of the products of the proton collisions with the vacuum chamber materials became essential. Berillium became the ideal candidate as structural material for the vacuum chamber due to its excellent mechanical properties and high transparency to radiation. Nonetheless, its toxicity, difficult machining and complicated weld hampers its use. TIG welding of beryllium to beryllium and to aluminium AA2219 was qualified for UHV applications as per ISO Norms applicable for aluminium welding. On the other hand, beryllium high price led to consider beryllium-aluminium composites for the fabrication of the LHCb vacuum chamber. The mechanical characterization of the berylliumaluminium HIP AlBeMet AM162 at the required bakeout temperatures of 200°C and 250°C was completed. In turn, the electron beam welding of beryllium-aluminium to beryllium-aluminium and to aluminium AA2219 was qualified for UHV applications following ISO Norms applicable for aluminium welding. Once characterized mechanically the materials and demonstrated the feasibility of the welding, nite element analysis were performed to design the vacuum chamber; as well as to design other special components integrated in it. The fabrication and thorough tests conducted with prototypes is described; in particular, an aluminium AA6061 OD860 mm window 2 mm thick that UHV seals one of the detectors, two bellows expansion joint aluminium fabricated in AA2219 and two optimized aluminium AA2219 UHV anges. The final design consisting of a TIG welded conical structure 12 m long fabricated in berillium with thickness ranging between 1 and 2.4 mm, implementing the validated aluminium window, optimized flanges and bellows expansion joints, will allow a factor 5 reduction of the radiation background generated by the initial vacuum chamber allowing the study of the physics that the LHCb experiment is designed for.

We present a preliminary risk analysis for the LHCb vertex locator (VELO). The scope of this risk analysis is to identify possible failure scenarios at the LHCb VELO and estimate the ensuing damage to equipment and downtime for LHC. Further, on the basis of a (preliminary) risk level for acceptability, we formulate requirements and suggest a number of precautions for the design of the VELO system.

Error fields in Tokamaks are small departures of the exact axisymmetry of the ideal magnetic field configuration. Their reduction beyond a threshold value by the error field correction coils is essential since sufficiently large static error fields lead to discharge disruption. The error fields are originated not only by coils fabrication and installation alignment tolerances, joints and busbars but also due to the presence of ferromagnetic elements. The start of plasma current flattop with relatively low plasma density is considered as a critical state of the 15 MA scenario for the onset of locked modes causing disruptions. A figure of merit, the ‘3-mode’ criterion, based on the lowest error field harmonics [(1,1); (2,1); (3,1)] was chosen to assess the error fields expected in ITER. Analysis performed last years in an independent way by CREATE (EU) and Efremov Inst. (RF) groups has allowed a deep understanding of the error fields induced by all the possible sources. Both groups were successfully benchmarked with the estimation of the error fields induced by a given deformed shape of a TF coil obtaining a perfect match of the results up to 2 orders of magnitude smaller than the defined threshold of B3-mode/Bto [1] ).