The physics programme and the design are described of a new collider for particle and nuclear physics, the Large Hadron Electron Collider (LHeC), in which a newly built electron beam of 60 GeV, up to possibly 140 GeV, energy collides with the intense hadron beams of the LHC. Compared to HERA, the kinematic range covered is extended by a factor of twenty in the negative four-momentum squared, $Q^2$, and in the inverse Bjorken $x$, while with the design luminosity of $10^{33}$ cm$^{-2}$s$^{-1}$ the LHeC is projected to exceed the integrated HERA luminosity by two orders of magnitude. The physics programme is devoted to an exploration of the energy frontier, complementing the LHC and its discovery potential for physics beyond the Standard Model with high precision deep inelastic scattering measurements. These are designed to investigate a variety of fundamental questions in strong and electroweak interactions. The physics programme also includes electron-deuteron and electron-ion scattering in a $(Q^2, 1/x)$ range extended by four orders of magnitude as compared to previous lepton-nucleus DIS experiments for novel investigations of neutron's and nuclear structure, the initial conditions of Quark-Gluon Plasma formation and further quantum chromodynamic phenomena. The LHeC may be realised either as a ring-ring or as a linac-ring collider. Optics and beam dynamics studies are presented for both versions, along with technical design considerations on the interaction region, magnets and further components, together with a design study for a high acceptance detector. Civil engineering and installation studies are presented for the accelerator and the detector. The LHeC can be built within a decade and thus be operated while the LHC runs in its high-luminosity phase. It thus represents a major opportunity for progress in particle physics exploiting the investment made in the LHC.

A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector

Our knowledge of the fundamental particles of nature and their interactions is summarized by the standard model of particle physics Advancing our understanding in this field has required experiments that operate at ever higher energies and intensities, which produce extremely large and information-rich data samples The use of machine-learning techniques is revolutionizing how we interpret these data samples, greatly increasing the discovery potential of present and future experiments Here we summarize the challenges and opportunities that come with the use of machine learning at the frontiers of particle physics

/pdf/machine-learning-at-the-energy-and-intensity-frontiers-of-39f23mkiln.pdf

Machine learning at the energy and intensity frontiers of particle physics.

The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.

The International Linear Collider Technical Design Report - Volume 3.II: Accelerator Baseline Design

The Integrable Optics Test Accelerator (IOTA) is a storage ring for advanced beam physics research currently being built and commissioned at Fermilab. It will operate with protons and electrons using injectors with momenta of 70 and 150 MeV/c, respectively. The research program includes the study of nonlinear focusing integrable optical beam lattices based on special magnets and electron lenses, beam dynamics of space-charge effects and their compensation, optical stochastic cooling, and several other experiments. In this article, we present the design and main parameters of the facility, outline progress to date and provide the timeline of the construction, commissioning and research. The physical principles, design, and hardware implementation plans for the major IOTA experiments are also discussed.

https://iopscience.iop.org/article/10.1088/1748-0221/12/03/T03002/pdf

IOTA (Integrable Optics Test Accelerator): Facility and Experimental Beam Physics Program

We report on the application of machine learning (ML) methods for predicting the longitudinal phase space (LPS) distribution of particle accelerators. Our approach consists of training a ML-based virtual diagnostic to predict the LPS using only nondestructive linac and e-beam measurements as inputs. We validate this approach with a simulation study for the FACET-II linac and with an experimental demonstration conducted at LCLS. At LCLS, the e-beam LPS images are obtained with a transverse deflecting cavity and used as training data for our ML model. In both the FACET-II and LCLS cases we find good agreement between the predicted and simulated/measured LPS profiles, an important step towards showing the feasibility of implementing such a virtual diagnostic on particle accelerators in the future.

/pdf/machine-learning-based-longitudinal-phase-space-prediction-2pqsmd0cg5.pdf

Machine learning-based longitudinal phase space prediction of particle accelerators

The PIP-II accelerator is a proposed upgrade to the Fermilab accelerator complex that will replace the existing, 400 MeV room temperature LINAC with an 800 MeV superconducting LINAC. Part of this upgrade includes a new injection scheme into the booster that levies tight requirements on the LLRF control system for the cavities. In this paper we discuss the challenges of the PIP-II accelerator and the present status of the LLRF system for this project.

Low Level RF Control for the PIP-II Accelerator

For the PIP-II Injector Test (PI-Test) at Fermilab, a four-vane radio frequency quadrupole (RFQ) is designed to accelerate a 30-keV, 1-mA to 10-mA, H- beam to 21 MeV under both pulsed and continuous wave (CW) RF operation The available headroom of the RF amplifiers limits the maximum allowable detuning to 3 kHz, and the detuning is controlled entirely via thermal regulation Fine control over the detuning, minimal manual intervention, and fast trip recovery is desired In addition, having active control over both the walls and vanes provides a wider tuning range For this, we intend to use model predictive control (MPC) To facilitate these objectives, we developed a dedicated control framework that handles higher-level system decisions as well as executes control calculations It is written in Python in a modular fashion for easy adjustments, readability, and portability Here we describe the framework and present the first control results for the PI-Test RFQ under pulsed and CW operation

Resonant Frequency Control For the PIP-II Injector Test RFQ: Control Framework and Initial Results

The SLAC National Accelerator Laboratory is building LCLS-II [1], a new 4 GeV CW superconducting (SCRF) Linac as a major upgrade of the existing LCLS. The LCLSII Low-Level Radio Frequency (LLRF) collaboration [2] is a multi-lab effort within the Department of Energy (DOE) accelerator complex. The necessity of high longitudinal beam stability of LCLS-II imposes tight amplitude and phase stability requirements on the LLRF system (up to 0.01% in amplitude and 0.01° in phase RMS) [3]. This is the first time such requirements are expected of superconducting cavities operating in continuous-wave (CW) mode. Initial measurements on the Cryomodule test stands at partner labs have shown that the early production units are able to meet the extrapolated hardware requirements to achieve such levels of performance [4]. A large effort is currently underway for system integration, Experimental Physics and Industrial Control System (EPICS) controls, transfer of knowledge from the partner labs to SLAC and the production and testing of 76 racks of LLRF equipment.

RF Controls for High-Q Cavities for the LCLS-II

This paper describes a recent effort to develop and benchmark a simulation tool for the analysis of radio frequency (RF) transients and their compensation in an H-linear accelerator. Existing tools in this area either focus on electron linear accelerators (LINACs) or lack fundamental details about the low level radio frequency system that are necessary to provide realistic performance estimates. In this paper, we begin with a discussion of our computational models followed by benchmarking with existing beam-dynamics codes and measured data. We then analyze the effect of RF transients and their compensation in the Proton Improvement Plan-II LINAC, followed by an analysis of calibration errors and how Newton’s method-based feedback scheme can be used to regulate the beam energy to within the specified limits.

RF Transient Analysis and Stabilization of the Phase and Energy of the Proposed PIP-II LINAC

Calabazas Creek Research, Inc., in collaboration with Fermilab and Communications & Power Industries, LLC. (CPI), is developing a phase locked, 100 kW peak, 10 kW average magnetron-based RF system for driving accelerators. Phase locking will be achieved using an approach originating at Fermilab [1] that includes control of both amplitude and phase on a fast time scale.

Brian Chase

Papers

Low Level RF Control for the PIP-II Accelerator

Resonant Frequency Control For the PIP-II Injector Test RFQ: Control Framework and Initial Results

RF Controls for High-Q Cavities for the LCLS-II

RF Transient Analysis and Stabilization of the Phase and Energy of the Proposed PIP-II LINAC

Advanced, phase-locked, 100 kW, 1.3 GHz magnetron