Canted Cosine Theta (CCT) magnet is an interesting design for compact accelerators or gantry systems for hadron-therapy. It offers great flexibility in generating complex field harmonics in straight and curved configurations while remaining compact. The Fusillo project based at CERN aims to design, build, and test a Nb-Ti curved CCT dipole demonstrator generating 3 T at 4.5 K in a large aperture of 236 mm, bent over 90(degrees) with a small bending radius of 1 m, and multi-harmonic field features to correct for the curvature. In this paper, we describe the fabrication process, the winding and the assembly of a Fusillo demonstrator that at present is being cold tested in liquid helium.

Due to its flexibility in generating advanced field harmonic corrections and potential for low cost compared to traditional designs, the Canted Cosine Theta (CCT) configuration is particularly interesting for compact particle accelerators and gantries for medical applications. This paper presents the design of a curved demonstrator named Fusillo, a Canted Cosine Theta Nb-Ti dipole magnet that is being developed at CERN, featuring a large aperture of 236 mm, a small bending radius of 1 m, a bending angle of 90 $^{\circ }$ , and multi-harmonic field correction, with a 3.61 T conductor peak field. We detail the magnetic coil design, incorporating high-order magnetic field correction of the errors produced by the heavily curved coil, peak field reduction at the coil ends, the development of a new rope type cable, and the mechanical design and the development of the former that supports the coil and provides the curved shape. We also present the first results of a subscale model used to qualify the coil's former manufacturing process, the rope cable, the coil winding optimization, and the coil impregnation system.

During the Long Shutdown 2 (LS2) at CERN, several upgrades were performed to beam intercepting devices in the framework of the HL-LHC Project. Upgraded equipment included two internal injection beam dumps (TDIS) intended for LHC machine protection located at the injection points from the SPS to the LHC. These two units have been assembled, tested and then installed around LHC Point 2 and Point 8 and are currently ready to get commis-sioned with beam. They are 5.8 m-long, three-module-seg-mented vacuum tanks, with large aperture to accommodate the injected and circulating beams and equipped with absorbing materials. These comprise graphite and higher-Z alloys that are embedded in sub-assemblies reinforced with back-stiffeners made of molybdenum alloy containing Ti and Zr (TZM).

The installation of Superconducting Radio Frequency (SRF) Crab Cavities is one of the key upgrades in the framework of the High Luminosity Large Hadron Collider (HL-LHC) at CERN. These devices - built out of 4mm thick niobium sheets - are shaped into complex geometries entailing very tight tolerances, in order to comply with strict SRF requirements. Numerical simulations of the sheet metal forming processes are used to optimize the fabrication of these SRF cavities by assessing different shaping approaches and tooling. Results of thickness distribution and geometrical shapes obtained from simulations are explored for an advanced design of the tooling. The tooling yields optimized shapes respecting the rigorous demands from the RF design. The following contribution details the numerical model used, presents the procedure and outcome of an advanced modeling of tooling and evaluates fabricated pieces.

Linac4 cesiated surface H− sources are routinely operated for the commissioning of the CERN’s Linac4 and on an ion source test stand. Stable current of 40-50 mA are achieved but the transmission through the LEBT of 80% was below expectations and triggered additional beam simulation and characterization. The H− beam profile is not Gaussian and emittance measurements are larger than simulation. The status of ongoing development work is described; 36 mA H− and 20 mA D− beams were produced with a 5.5 mm aperture cesiated surface ion source. The emittances measured at the test stand are presented. During a preliminary test, the Linac4 proton source delivered a total beam intensity of 70 mA (p, H2+, H3+).

In all existing large particle accelerators (Tevatron, HERA, RHIC, LHC) the main superconducting magnets are based on Rutherford cables, which are characterized by having: strands fully transposed with respect to the magnetic field, a significant compaction that assures a large engineering critical current density and a geometry that allows efficient winding of the coils. The Nb3Sn magnets developed in the framework of the HL-LHC project for improving the luminosity of the Large Hadron Collider (LHC) are also based on Rutherford cables. Due to the characteristics of Nb3Sn wires, the cabling process has become a crucial step in the magnet manufacturing. During cabling the wires experience large plastic deformations that strongly modify the geometrical dimensions of the sub-elements constituting the superconducting strand. These deformations are particularly severe on the cable edges and can result in a significant reduction of the cable critical current as well as of the Residual Resistivity Ratio (RRR) of the stabilizing copper. In order to understand the main parameters that rule the cabling process and their impact on the cable performance, CERN has developed a 3D Finite Element (FE) model based on the LS-Dyna® software that simulates the whole cabling process. In the paper the model is presented together with a comparison between experimental and numerical results for a copper cable produced at CERN.

CERN’s Proton Synchrotron Booster (PSB) is undergoing a major upgrade program in the frame of the LHC Injectors Upgrade (LIU) project. During the first long LHC shutdown (LS1) some parts of the upgrade have already been implemented, and the machine has been successfully re-commissioned. More work is planned for the upcoming end-of-year technical stops, notably in 2016/17, while most of the upgrade is planned to take place during the second long LHC shutdown (LS2). We report on the upgrade items already completed and commissioned, the first Run 2 beam performance and give a status of the ongoing design and integration work.

Two volume sources equipped with DESY and CERN plasma generators and a low voltage electron dump were operated at 45 kV in the Linac4 tunnel and on a dedicated test stand. These volume sources delivered approximately 20 mA and ensured the commissioning of the Radio Frequency Quadrupole accelerator and of the first section of the Drift Tube Linac. CERN's prototype of a cesiated surface source equipped with this electron dump was operated continuously from November 2013 to April 2014 on the ion source test stand and is being commissioned in the Linac4 tunnel. Before cesiation, the prototype conditioned in volume mode provided up to 30 mA H- beam. Short cesiations, of the order of 10 mg effectively reduced the intensity of co-extracted electrons down to 2 - 8 times the H- current; this cesiated surface operation mode delivered up to 60 mA H- beam. An H- beam of the order of 40 mA was sustained up to four weeks operation with 500 mu s pulses at 1.2s spacing. A new extraction was designed to match these beam properties. A copy of BNL's magnetron produced at CERN was tested at BNL and delivered at 40 kV H- beam exceeding Linac4's nominal intensity of 80 mA.In this contribution, the performances, dynamic response to cesiation, stability and availability of these prototypes are described. The needed optimization of the emittance of H- beam above 40 mA is presented, which requires an evolution of the front end that encompasses implementation of a large ceramic insulator.

Collimators for last-generation particle accelerators like the LHC, must be designed to withstand the close interaction with intense and energetic particle beams, safely operating over an extended range of temperatures in harsh environments, while minimizing the perturbing effects, such as instabilities induced by RF impedance, on the circulating beam. The choice of materials for collimator active components is of paramount importance to meet these requirements, which are to become even more demanding with the increase of machine performances expected in future upgrades, such as the High Luminosity LHC (HL-LHC). Consequently, a farreaching R&D program has been launched to develop novel materials with excellent thermal shock resistance and high thermal and electrical conductivity, replacing or complementing materials used for present collimators. Molybdenum Carbide Graphite and Copper-Diamond composites have been so far identified as the most promising materials. The manufacturing methods, properties and application potential of these composites will be reviewed along with the experimental program which is to test their viability when exposed to high intensity particle beams.

CERN's 160 MeV H(-) linear accelerator (Linac4) is a key constituent of the injector chain upgrade of the Large Hadron Collider that is being installed and commissioned. A cesiated surface ion source prototype is being tested and has delivered a beam intensity of 45 mA within an emittance of 0.3 π ⋅ mm ⋅ mrad. The optimum ratio of the co-extracted electron- to ion-current is below 1 and the best production efficiency, defined as the ratio of the beam current to the 2 MHz RF-power transmitted to the plasma, reached 1.1 mA/kW. The H(-) source prototype and the first tests of the new ion source optics, electron-dump, and front end developed to minimize the beam emittance are presented. A temperature regulated magnetron H(-) source developed by the Brookhaven National Laboratory was built at CERN. The first tests of the magnetron operated at 0.8 Hz repetition rate are described.

The unprecedented energy intensities of modern hadron accelerators yield special problems with the materials that are placed close to or into the high intensity beams. The energy stored in LHC in a single beam is equivalent to about 80 kg of TNT explosive, stored in a transverse beam area of 0.2 mm × 0.2 mm. The materials placed close to the beam are used at, or even beyond, their damage limits. However, it is very difficult to predict structural efficiency and robustness accurately: beam-induced damage occurs in a regime where practical experience does not exist. This study is performed in order to estimate the damage on a copper component due to the impact with a 7 TeV proton beam generated by LHC. The case study represents an accidental case consequent to an abnormal release of the beam, in which 8 bunches irradiate the target directly. The energy delivered on the component is calculated using the FLUKA code and then used as input in the numerical simulations, that are carried out via the FEM code LS-DYNA. Different numerical models are realized trying to obtain the simplest model able to correctly describe the material response without affecting the goodness of the results.

At present, the beam-based alignment of the LHC collimators is performed by touching the beam halo with both jaws of each collimator. This method requires dedicated fills at low intensities that are done infrequently and makes this procedure time consuming. This limits the operational flexibility, in particular in the case of changes of optics and orbit configuration in the experimental regions. The performance of the LHC collimation system relies on the machine reproducibility and regular loss maps to validate the settings of the collimator jaws. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with jaw-integrated Beam Position Monitors (BPMs) was proposed and successfully tested with a prototype (mock-up) collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper, the results of these experiments are discussed. The non-linear response of the BPMs is compared to the predictions from electromagnetic simulations. Finally, the measured alignment accuracy is compared to the one achieved with the present collimators in the LHC.

State-of-the art complex numerical methods based on advanced wave propagation codes have been developed to study the extreme phenomena induced in Beam Intercepting Devices (BID) by accidental beam impacts. A first study, based on these methods, led to the identification of damage thresholds for LHC Tertiary Collimators which were presented at Chamonix workshop in 2011. However, numerical simulations were unavoidably affected by uncertainties due to the limited knowledge of the material constitutive models; two experiments in the HiRadMat facility were proposed to address this issue: the destructive test of a complete tertiary collimator for a thorough, integral assessment of beam accident consequences (HRMT09) and a controlled test on a multi-material test bench hosting a variety of specimens conveniently instrumented for online and offline measurements (HRMT14). Both experiments were very successful and confirmed the effectiveness of numerical methods and material models to reliably predict beam-induced damages. Preliminary data acquired during HRMT14 provided interesting results on the ability of various materials to withstand extreme accidents. These tests also highlighted additional potential machine protection issues, on top of mechanical damage, induced by the projection of fragments out of the tungsten jaw: these include UHV degradation, chamber pollution, contamination, etc. In line with updated accident scenarios, new damage limits are proposed for LHC Tertiary Collimators.

The correct functioning of a collimation system is crucial to safely operate highly energetic particle accelerators, such as the Large Hadron Collider (LHC). The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs) in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN High-Radiation to Materials (HiRadMat) facility, involved 440 GeV proton beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained, together with some first outcomes from visual inspection and a comparison of such results with numerical simulations.

In view of High Luminosity LHC (HL-LHC) upgrades, collimator materials may become a limit to the machine performance: the high RF impedance of Carbon-Carbon composites used for primary and secondary collimators can lead to beam instabilities, while the Tungsten alloy adopted in tertiary collimators exhibits low robustness in case of beam-induced accidents. An R&D program has been pursued to develop new materials overcoming such limitations. Molybdenum-Graphite, in addition to its outstanding thermal conductivity, can be coated with pure molybdenum, reducing collimator impedance by a factor of 10. A new secondary collimator is being designed around this novel composite. New high-melting materials are also proposed to improve the robustness of tertiary collimators. New collimators will also be equipped with BPMs, significantly enhancing the alignment speed and the beta-star reach. This implies additional constraints of space, as well as detailed static and fatigue calculations on cables and connectors. This paper describes the mechanical design and the engineering calculations of such future collimators, focusing on the study via state-ofthe-art numerical methods of interactions between the particle beams and the new materials adopted.