Tracking Studies in the LHeC Lattice

The Large Hadron Electron Collider (LHeC) is a proposed upgrade of the LHC to provide electron-proton collisions and explore a new regime of energy and luminosity for nucleon-lepton scattering. A nominal design has previously been presented, featuring a lattice and optical configuration to focus one of the proton beams of the LHC (reaching a value of β*=10 cm) and to collide it head-on with an electron beam to produce collisions with the desired luminosity of L=10³³ cm⁻² s⁻¹. The proton beam optics is achieved with the aid of a new inner triplet of quadrupoles at L*=10 m from the interaction point and the extension of the Achromatic Telescopic Squeezing (ATS) Scheme used for the High Luminosity-LHC project. The flexibility of this design has been studied in terms of minimising β* and increasing L*. In this work, particle tracking is performed in a thin lens approximation of the LHeC proton lattice to compute the dynamic aperture and perform frequency map analysis for different types of chromatic correction schemes, in order to find the one who will provide the most beam stability and to study the effects of non linearities

LHeC optics with β∗ = 10 cm and L∗ = 15 m

New proton optics have been designed for LHeC taking into account new final focus magnet designs and ensuring a full compatibility with HL-LHC version 1.3. The distance between the interaction point (IP) and the first quadrupole has been increased to 15 m to alleviate synchrotron radiation. The smallest β∗ found compatible with magnet aperture is β∗ = 10 cm. Chromaticity correction is demonstrated down to β∗ = 7 cm with acceptable Dynamic Aperture (DA). Ideas and challenges are discussed for β∗ = 5 cm and a new possible final focus based on quadrupole doublets

RF multipoles deliverable

The crab cavities to be installed in the High-Luminosity LHC (HL-LHC) aim to provide an increase in luminosity by restoring head-on collisions and therefore reducing the loss of luminosity due to the crossing angle. The crab cavities rotate the beam by providing z-dependent kicks near the interaction point. Two designs have been cast for this task: the RF dipole (RFD) and the Double Quarter Wave (DQW); a prototype of the latter one has been installed in the SPS and in 2018 the first successful crabbing of proton beams was achieved. As the design of both these crab cavities has to be very compact to be able to fit between the two beams, this causes a loss of axial symmetry that gives rise to high order multipoles. This study aims to explore the impact and tolerances of the high order multipoles on beam dynamics by performing DA studies on the HL-LHC lattice

LHeC IR Optics Design Integrated into the HL-LHC Lattice

The LHeC is a proposed upgrade to the LHC to provide electron-proton collisions and explore the new regime of energy and intensity for lepton-nucleon scattering. The work presented here investigates optics and layout solutions allowing simultaneous nucleon-nucleon and lepton-nucleon collisions at separate interaction points compatible with the proposed HL-LHC lattice. A first lattice design has been proposed that collides proton beam 2 with the electron beam. The nominal design calls for a β^{*} (beta function in the interaction point ) of 10 cm using an extended version of the Achromatic Telescopic Squeezing (ATS) scheme, and a L* (distance to the inner triplet) of 10 m. Modifying these two parameters, β^{*} and L*, can provide benefits to the current design since the values of these parameters have direct effects on the luminosity, the natural chromaticity and the synchrotron radiation of the electron beam. This work aims to explore the range over which these parameters can be varied in order to achieve the desired goal

A code for optimising triplet layout

One of the main challenges when designing final focus systems of particle accelerators is maximising the beam stay clear in the strong quadrupole magnets of the inner triplet. Moreover it is desirable to keep the quadrupoles in the inner triplet as short as possible for space and costs reasons but also to reduce chromaticity and simplify corrections schemes. An algorithm that explores the triplet parameter space to optimise both these aspects was written. It uses thin lenses as a first approximation for a broad parameter scan and MADX for more precise calculations. The thin lens algorithm is significantly faster than a full scan using MADX and relatively precise at indicating the approximate area where the optimum solution lies

HE-LHC Final Focus: Flat Beam Parameters and Energy Deposition Studies

The High Energy LHC (HE-LHC) project is studying the feasibility of a new proton-proton collider with a beam energy of 13.5 TeV. The nominal optics features a β^{*} of 0.25 m and crab-cavities. Here we present a flat-beam optics that can be used with a non-zero crossing angle, in the absence of crab cavities. This is followed by energy deposition studies for the superconducting quadrupoles and dipole separators. The total dose in these magnets coming from the collision debris is evaluated