Search

Long-range beam-beam (LRBB) interactions can be a source of emittance growth and beam losses in the LHC during physics and will become even more relevant with the smaller '* and higher bunch intensities foreseen for the High Luminosity LHC upgrade (HL-LHC), in particular if operated without crab cavities. Both beam losses and emittance growth could be mitigated by compensat-ing the non-linear LRBB kick with a correctly placed current carrying wire. Such a compensation scheme is currently being studied in the LHC through a demonstration test using current-bearing wires embedded into col-limator jaws, installed either side of the high luminosity interaction regions. For HL-LHC two options are considered, a current-bearing wire as for the demonstrator, or electron lenses, as the ideal distance between the particle beam and compensating current may be too small to allow the use of solid materials. This paper reports on the ongoing activities for both options, covering the progress of the wire-in-jaw collimators, the foreseen LRBB experiments at the LHC, and first considerations for the design of the electron lenses to ultimately replace material wires for HL-LHC., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The compensation of long-range beam-beam interaction with current wires is considered as a possible technology for the HL-LHC upgrade project. A demonstration experiment is planned in the present LHC machine starting in 2018. This paper summarizes the tracking studies of long range beam-beam effect compensation in the LHC aimed to aid in planning the demonstration experiment. The impact of wire compensators is demonstrated on the tune footprints, dynamic aperture, beam emittance and beam intensity degradation. The simulations are performed with SIXTRACK code. The symplectic transport map for the wire element, its verification and implementation into the code are also discussed., Proceedings of the North American Particle Accelerator Conf., NAPAC2016, Chicago, IL, USA

An electronic unit is required for each CLIC “Two Beam Module”. This study aims to estimate the potential damage due to the prompt radiation to the electronics units installed inside the CLIC Main Linac tunnel. Sets of Monte-Carlo simulations have been done to estimate damage to electronics installed at various locations inside the tunnel. Continuous and point beam losses have been considered for CLIC Main and Drive beams. Lead and iron in combination with a polyethylene layer were investigated as a possible shielding. The upper limits of the estimated quantities are presented for stand alone and shielded electronics.

Experimental studies of neutron spectra of three different subcritical assemblies driven by an accelerator (Accelerator Driven Systems – ADS) for investigation of the possibility of transmutation and energy amplification have been carried out. The assemblies were constructed in the framework of the international project “Energy and Transmutation of Radioactive Wastes” and experiments with them are running in the Veksler and Baldin Laboratory of High Energy Physics of the Joint Institute for Nuclear Research (Dubna, Russia) at the accelerator complex “Nuclotron”. In this paper the results of measurements of 239Pu(n, f), 235U(n, f), 238U(n, f) and 238U(n,γ) reactions cross-sections and reactions rates using solid state nuclear track detectors and activation gamma-spectroscopy are presented. A comparison of the experimental results with FLUKA calculations is given. The obtained experimental values characterize the neutron spectra in the experimental points and allow the efficiency of the ADS technology for the systems with similar parameters to be evaluated., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany