A Hollow Electron Lens (HEL) is currently under development for the High-Luminosity upgrade of the Large Hadron Collider (HL-LHC). In this device, a hollow electron beam co-propagates with a central proton beam and provides active halo control in the LHC. To ensure the concentricity of the two beams, a non-invasive diagnostic instrument is currently being commissioned. This instrument is a compact version of an existing prototype that leverages beam induced fluorescence with supersonic gas curtain technology. This contribution includes the design features of this version of the monitor, recent progress, and future plans for tests at the Cockcroft Institute and the electron lens test stand at CERN.

Non-Invasive Beam Profile Monitoring for the HL-LHC Hollow Electron Lens

Experiments with low energy antiprotons are at the cutting edge of science and offer unique opportunities to test some of the fundamental laws of physics. The experiments are, however, very difficult to realize. They critically depend on high performance numerical tools that can model realistic beam transport and storage and also require advanced beam monitors and detectors that can fully characterize the beam. Finally, novel experiments need to be designed that exploit the enhanced beam quality that the new ELENA ring at CERN provides. This paper presents some selected findings from the panEuropean AVA network's three scientific work packages. It shows results from studies into electron cooling at the new ELENA storage ring, research into carbon nanotubes as cold electron field emitters for electron cooling and how antiproton-atom collision experiments can be optimized using GEANT4. Finally, the paper gives an overview of the network’s interdisciplinary training program.

New Opportunities in Low Energy Antiproton Research

Recent Progress on the Commissioning of a Gas Curtain Beam Profile Monitor Using Beam Induced Fluorescence for High Luminosity LHC

Characterization of a supersonic molecular beam for charged particle beam profile monitor

The Beam-Gas Curtain or BGC is the baseline instrument for monitoring the concentricity of the LHC proton beam with a hollow electron beam for the hollow e-lens (HEL) beam halo suppression device which is part of the High-Luminosity LHC upgrade. The proof-of-principles experiments of this gas-jet monitor have now been developed into a prototype instrument which has been built for integration into the LHC ring and is now under phased installation for operation in the upcoming LHC run. This paper describes the challenges overcome to produce a gas-jet fluorescence monitor for the ultra-high vacuum accelerator environment. It also presents preliminary results from the installation of the instrument at CERN.

Design of a prototype gas jet profile monitor for installation into the large hadron collider at cern ∗

Non-invasive beam profile monitor for medical accelerators.

The interaction between antiprotons and hydrogen or helium atoms is a fundamental problem in many-particle atomic physics, attracting strong interest from both theory and experiments. Atomic collisions are ideal to study the three and four-body Coulomb problem as the number of possible reaction channels is limited. Currently, only the total cross-sections of such interactions have been measured in an energy range between keV and a few MeV. This contribution investigates the discrepancies between different theories and available experimental data. It also describes a pathway for obtaining differential cross-sections. A purpose-designed experimental setup is presented and detailed Geant4 simulations provide an insight into the interaction between short (ns) antiproton bunches and a dense gas-jet target.

Narender Kumar

Papers

Non-invasive beam profile monitor for medical accelerators.

Non-Invasive Beam Profile Monitoring for the HL-LHC Hollow Electron Lens

Recent Progress on the Commissioning of a Gas Curtain Beam Profile Monitor Using Beam Induced Fluorescence for High Luminosity LHC

Design of a prototype gas jet profile monitor for installation into the large hadron collider at cern ∗

Optimization of Antiproton-Atom Collision Studies Using GEANT4