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To show the Hertz-Knudsen equation is applicable to the prediction of the evaporation rates of Li and volatile impurities from the Li target surface at the International Fusion Materials Irradiation Facility (IFMIF), we analytically and experimentally studied these rates for a high-speed Li jet via engineering-scale tests performed under IFMIF conditions (vacuum pressure: 10−3 Pa, Li temperature: 250 °C, jet speed: 7–15 m/s). The rates of evaporation and deposition were analytically predicted using the Hertz–Knudsen equation and the cosine law with known Li impurity concentrations (36 wppm for Na and 10 wppm or less for K). As pointed out in earlier works, Na and K are volatile impurities in Li. The evaporation rates of Na and K from liquid Li at a temperature of 250 °C are non-negligible, even if their concentrations in Li are as small as tens of wppm. To measure the deposition rate of evaporants from the Li jet, we used a quartz crystal microbalance and a neutralization titration method. The measured deposition rate was highly consistent with the deposition rate estimated analytically for weak evaporation. Also, the measured deposition rate was independent of the flow speed in the range of 7–15 m/s. We concluded that combining the Hertz–Knudsen equation and the cosine law is a reliable method for predicting the evaporation and deposition rates of Li and volatile impurities from a Li jet surface at the IFMIF.

The Radio Frequency Quadrupole (RFQ) linac and 1.6 MW RF power system of the Linear IFMIF Prototype Accelerator (LIPAc) facility in the International Fusion Energy Research Center (IFERC) in Rokkasho (Japan) has been installed and conditioned. During the assembly and uning process, the RFQ cavity was protected with a temporary tent from the potential deterioration of performance caused by dust. The vacuum in the cavity was improved through the 100 °C baking rocess of the cavity. The high power test of the 175 MHz RF systems up to 200 kW in CW for each of the eight RF chains was performed for checking its stable output reproducibility in Japan, before connecting 9–3/16 inch coaxial transmission lines from the RF chains to the RF input couplers of the cavity. It was confirmed that the eight RF chains provided the balanced RF power to the single RFQ cavity inphase using a feedback loop and a synchronization system. The peak power in the cavity achieved 150 kW in the pulsed mode, which corresponds approximately to the required electric field to accelerate proton beam. Such RF conditioning process is ongoing to achieve 600 kW approximately required for deuteron beam commissioning planned in 2018.

The necessity of a neutron source for fusion materials research was identified already in the 70s. Though neutrons induced degradation present similarities on a mechanistic approach, thresholds energies for cru- cial transmutations are typically above fission neutrons spectrum. The generation of He via 56 Fe (n, α) 53 Cr in future fusion reactors with around 12 appm/dpa will lead to swelling and structural materials embrittlement. Existing neutron sources, namely fission reactors or spallation sources lead to different degradation, attempts for extrapolation are unsuccessful given the absence of experimental observations in the operational ranges of a fusion reactor. Neutrons with a broad peak at 14 MeV can be generated with Li(d,xn) reactions; the technological effort s that started with FMIT in the early 80s have finally ma- tured with the success of IFMIF/EVEDA under the Broader Approach Agreement. The status today of five technological challenges, perceived in the past as most critical, are addressed. These are: 1. the feasibil- ity of IFMIF accelerators, 2. the long term stability of lithium flow at IFMIF nominal conditions, 3. the potential instabilities in the lithium screen induced by the 2 ×5 MW impacting deuteron beam, 4. the uniformity of temperature in the specimens during irradiation, and 5. the validity of data provided with small specimens. Other ideas for fusion material testing have been considered, but they possibly are ei- ther not technologically feasible if fixed targets are considered or would require the results of a Li(d,xn) facility to be reliably designed. In addition, today we know beyond reasonable doubt that the cost of IFMIF, consistently estimated throughout decades, is marginal compared with the cost of a fusion reactor. The less ambitious DEMO reactor performance being considered correlates with a lower need of fusion neutrons flux; thus IFMIF with its two accelerators is possibly not needed since with only one acceler- ator as the European DONES or the Japanese A-FNS propose, the present needs > 10 dpa/fpy would be fulfilled. World fusion roadmaps stipulate a fusion relevant neutron source by the middle of next decade, the success of IFMIF/EVEDA phase is materializing this four decades old dream.

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.