Search

International audience; The computation of analytic and numerical beam based quantities are derived for full 3D representation of the quadrupoles magnetic field, which can be computed by finite element code or measured. The impact of this more accurate description of the non homogeneity of the field is estimated on beam based observables and non linear correctors strengths, and compared with the less accurate models in the case of HL-LHC.

Accelerator physics needs advanced modeling and simulation techniques, in particular for beam stability studies. A deeper understanding of the effects of magnetic fields non-linearities will greatly help in the improvement of future colliders design and performance. In *, a new tracking method was proposed to study the effect of the longitudinal dependency of the harmonics on the beam dynamics. In this paper, the study will focus on the effects on observable quantities in beam based measurements, for the case of HL-LHC Inner Triplet and with possible tests in LHC., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

The Accelerator Test Facility 2 (ATF2) at KEK is a prototype for the Final Focus Systems of the future e⁺e⁻ linear colliders, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC). In this paper both simulation and experimental results are presented with special emphasis on intensity-dependent effects. The importance of these effects is shown using the PLACET code and realistic ATF2 machine simulations (including beam jitter, misalignment, wakefield, Beam Based Alignment (BBA) correction, …). The latest experimental results are also presented, in particular the impact of the beam intensity on the beam size at the IP., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

International audience; NICA (Nuclotron-based Ion Collider fAcility) [1] is a heavy-ion collider for studying the properties of hot and dense baryonic matter to be constructed at JINR (Dubna). A major restricting factor on the NICA’s transverse dynamic aperture is the nonlinear fringe field of final-focus quadrupole lenses. We propose to enhance the NICA dynamic aperture with a set of multipole lenses whose characteristics and configuration are optimized using a genetic algorithm.

International audience; Aiming to simplify the machine detector interface of the Compact Linear Collider (CLIC), a new detector model has been designed allowing the last quadrupole QD0 of the final focus system (FFS) to be located outside of the experiment with a distance L* from the interaction point of 6 m. In this paper, the beam delivery system (BDS) has been reoptimized, offering a luminosity performance that exceeds the design requirements by 11% for the total luminosity and by 7% in the energy peak. A simulation campaign has been carried out and has proved the feasibility of recovering the luminosity under realistic transverse misalignments of the FFS optics, by means of different orbit and aberration correction techniques, making this long L* design a realistic candidate for the future CLIC BDS.

International audience; The Compact Linear Collider (CLIC) project is right in the development phase. In this prospect, the main objective of the final focus stabilization is to succeed in damping ground motion vibration at the sub-nanometer scale to avoid any unwanted motion of the two last final focus magnets. Active vibration control using high-resolution industrial seismic sensors has already shown its limits in the desired range of attenuation [4-100] Hz. Hence, a dedicated inertial sensor has been designed, tuned to fit CLIC requirements. It doesn't contain any feedback or coil which would linearize its dynamic in its bandwidth [0.1-100] Hz, avoiding electrical noise or thermal noise, and when used for active control, enhancing its performances thanks to the internal resonance. An analytical modeling of the sensor dynamic behavior also shown experimentally gives a first internal resonance around 11 Hz. This paper is complemented by a comparative measurement with high precision industrial sensors. A noise level 2.5 times better (0.04 nm at 4 Hz) has been achieved. This sensor has also been tested in the context of vibration rejection with a sub-nanometer active vibration rejection support. Experimental results have been compared with the one obtained with the state-of-the-art industrial sensors. Vertical seismic motion attenuation results have shown unprecedented performances. A damping ratio of 8.5 has been achieved at 4 Hz, leading to an rms displacement of the support of 0.25 nm thanks to the active support prototype and the dedicated sensor.

The SuperKEKB B-Factory at KEK (Japan), after few years of shutdown for the construction and renovation, has finally come to the Phase-1 commissioning of the LER and HER rings, without the final focus system and the Belle II detector. Vacuum scrubbing, optics tuning and beam related background measurements were performed in this phase. Low emittance tuning techniques have also been applied in order to set up the rings for Phase-2 with colliding beams next year. An update of the final focus system construction, as well as the status of the injection system with the new positron damping ring and high current/low emittance electron gun is also presented., Proceedings of the North American Particle Accelerator Conf., NAPAC2016, Chicago, IL, USA