Machine layout and performance

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC

Low energy and high energy dumps for ELI-NP accelerator facility: rational and Monte-Carlo calculationsș results

ELI-NP will be a new international research infrastructure facility for laser-based Nuclear Physics to be built in Magurele, south west of Bucharest, Romania. For the machine to operate as an intense γ rays’ source based on Compton back-scattering, electron beams are employed, undergoing a two stage acceleration to 320 MeV and 740 MeV (and, with an eventual energy upgrade, also to 840 MeV) beam energies. In order to assess the radiation safety issues, concerning the effectiveness of the dumps in absorbing the primary electron beams, the generated prompt radiation field and the residual dose rates coming from the activation of constituent materials, as well as the shielding of the adjacent environments against both prompt and residual radiation fields, an extensive design study by means of Monte Carlo simulations with FLUKA code was performed, for both low energy 320 MeV and high energy 720 MeV (840 MeV) beam dumps. For the low energy dump we discuss also the rational of the choice to place it in the building basement, instead of installing it in one of the shielding wall at the machine level, as it was originally conceived. Ambient dose equivalent rate constraints, according to the Rumenian law in force in radiation protection matter were 0.1 /iSv/h everywhere outside the shielding walls and 1.4 μiSv/h outside the high energy dump area. The dumps’ placements and layouts are shown to be fully compliant with the dose constraints and environmental impact

Low energy and high energy dumps for ELI-NP accelerator facility: rational and Monte-Carlo calculationsș results

ELI-NP will be a new international research infrastructure facility for laser-based Nuclear Physics to be built in Magurele, south west of Bucharest, Romania. For the machine to operate as an intense γ rays’ source based on Compton back-scattering, electron beams are employed, undergoing a two stage acceleration to 320 MeV and 740 MeV (and, with an eventual energy upgrade, also to 840 MeV) beam energies. In order to assess the radiation safety issues, concerning the effectiveness of the dumps in absorbing the primary electron beams, the generated prompt radiation field and the residual dose rates coming from the activation of constituent materials, as well as the shielding of the adjacent environments against both prompt and residual radiation fields, an extensive design study by means of Monte Carlo simulations with FLUKA code was performed, for both low energy 320 MeV and high energy 720 MeV (840 MeV) beam dumps. For the low energy dump we discuss also the rational of the choice to place it in the building basement, instead of installing it in one of the shielding wall at the machine level, as it was originally conceived. Ambient dose equivalent rate constraints, according to the Rumenian law in force in radiation protection matter were 0.1 /iSv/h everywhere outside the shielding walls and 1.4 μiSv/h outside the high energy dump area. The dumps’ placements and layouts are shown to be fully compliant with the dose constraints and environmental impact

An intrinsically safe facility for forefront research and training on nuclear technologies - Burnup and transmutation

The currently dominant open fuel cycles have resulted in the gradual accumulation of (relatively) large quantities of highly radioactive or fertile materials in the form of depleted uranium, plutonium, minor actinides (MA) and long-lived fission products (LLFP). For low-activity wastes a heavily shielded surface repository is required. Spent fuel can be instead directly buried in deep geological repositories or reprocessed in order to separate U and Pu and eventually also MA and LLFP from other materials. These elements can be further burnt by modern reactors but not yet in sufficient quantities to slow down the steady accumulation of these materials in storage. Using ADS, the residual long-lifetime isotopes can be transmuted by nuclear reactions into shorter-lifetime isotopes again storable in surface repositories. However, in order to perform transmutations at a practical level, high-power reactors (and consequently high-power accelerators) are required; particularly, a significant transmutation can be reached not only by increasing the beam current to something of the order of a few tens of mA, but also by increasing the beam energy above 500MeV in order to reach the spallation regime. Such high-power infrastructures require intermediate test facilities with lower power and higher safety level for the investigation of their dynamics and transmutation capabilities: the ADS proposed in this study could accomplish many of these constraints

Impedance simulations and measurements on the LHC collimators with embedded beam position monitors

The LHC collimation system is a critical element for the safe operation of the LHC machine. The necessity of fast accurate positioning of the collimator’s jaws, recently introduced the need to have button beam position monitors directly embedded in the jaws extremities of the LHC tertiary collimators and some secondary collimators. This addition led to a new design of these collimators including ferrites to damp higher order modes instead of rf fingers. In this work we will present the impedance bench measurements and simulations on a TCT (Transverse Tertiary Collimator) prototype including estimations for beam stability for the LHC