Beam Diagnostics Measurements at 3MeV of the LINAC4 H⁻ Beam at CERN

Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366), 1999

Six years before the scheduled commissioning of the LHC at CERN, the basic list of beam instruments has been established. This early date is needed due to the impact of the mechanical design of some detectors (mainly the beam position detectors) on the cryogenic part of the machine as well as for other projects due to the long R&D period (emittance measurements, tune and chromaticity diagnostics and control). This paper gives a detailed overview of the basic requirements and specifications of all beam instruments foreseen for transfer lines and main rings.

2006

Even though CERN's Large Hadron Collider (LHC) is mainly conceived to accelerate protons, a heavy ion physics program is also foreseen. In order to reach the luminosity required for LHC, the ion accelerator chain needed to be upgraded, and a central part is the new Low Energy Ion Ring (LEIR). Its role is to transform a series of long, low-intensity ion pulses from Linac-3 into short, high-density pulses which will be further accelerated in the PS and SPS rings before injection into LHC. To do so the injected pulses are stacked and phase-space cooled using electron cooling before acceleration to the ejection energy of 72 MeV/u. This note describes the different types of instruments used in the LEIR ring and transfer lines and reports on the first results obtained with O4+ and Pb54+ beams.

2011

The Hsource and the low energy beam transport (LEBT) line will determine to a large extend the performance of Linac-4, the new machine foreseen at CERN as injector into the PS Booster. For this reason a test stand is being set up, consisting of the source, the LEBT, the RFQ and the chopper line. Up to now only the source and LEBT are installed. First measurements have been performed using a Faraday Cup to measure the total source intensity, a slit and grid emittance meter for transverse emittance measurements as well as a spectrometer for energy spread measurements. Beam intensity, profile, transverse emittance and energy spread have been measured. The paper discusses measurements done on Hbeams at 35 kV extraction voltage as well as proton beams at 45 keV.

Proceedings of The European Physical Society Conference on High Energy Physics — PoS(EPS-HEP2021), 2022

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2005

Modern diagnostic techniques provide detailed information on beam conditions in injector, transport, and final focus experiments in the HIF-VNL. Parameters of interest include beam current, beam energy, transverse and longitudinal distributions, emittance, and space charge neutralization. Imaging techniques, based on kapton films and optical scintillators, complement and in some cases, may replace conventional techniques based on slit scans. Time-resolved optical diagnostics that provide 4-D transverse information on the experimental beams are in operation on the existing experiments. Current work includes a compact optical diagnostic suitable for insertion in transport lines, improved algorithms for optical data analysis and interpretation, a high-resolution electrostatic energy analyzer, and an electron beam probe. A longitudinal diagnostic kicker generates longitudinal space-charge waves that travel on the beam. Time of flight of the space charge waves and an electrostatic energy analyzer provide an absolute measure of the beam energy. Special diagnostics to detect secondary electrons and gases desorbed from the wall have been developed.

2018

The strategy for machine protection and quench prevention of the super-conducting elements of the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is heavily reliant on its beam loss monitoring system. This is one of the most complex and large-scale beam instrumentation systems deployed anywhere in the world. In order to augment the system's dependability and verify the correct connection of each of the approximately 4000 detectors distributed around the 27 km LHC ring to its assigned channel in the electronic system, a mobile irradiation instrument has been designed and built. This instrument can be easily and safely transported along the LHC tunnel and imitate a localised beam loss at each BLM detector. This paper describes the concept of the instrument, its engineering design, the safety measures included and recent upgrades. Possible future improvements of the device are also considered.

2018

A new generation of beam wire scanner (BWS), for transversal beam profile monitoring, is under development on the framework of the LHC Injector Upgrade project at CERN. Two pre-series prototypes have been built and installed in the Super Proton Synchrotron and Proton Synchrotron Booster, to assess the performance of the upgraded BWS concept. This contribution shows the outcome of the measurement campaigns carried out on the first BWS prototypes, both in the laboratory and with proton beams. An evaluation of a high dynamic range acquisition system for the measurement of the secondary showers produced by the beam-wire interaction is also presented.

2017

During the Long Shutdown 2 (LS2) at CERN in 2019/20, the Proton Synchrotron Booster (PSB) will undergo a profound upgrade in the framework of the LHC Injector Upgrade (LIU) project involving also the connection to the new Linac4 injector. The 160 MeV Linac4 H − injection entails a complete replacement of the PSB injection section, including a stripping foil system, injection chicane, an H 0 /H − dump and novel beam instrumentation. The equivalent of half of this new injection chicane was temporarily installed in the Linac4 transfer line to evaluate the performance of the equipment and prepare controls, interlocks and applications for the connection. Outcomes of this so-called Half-Sector Test (HST) are presented in this paper.

AIP Conference Proceedings, 2004

An Energy Recovery Linac (ERL) test facility is presently under construction at BNL. The goals of this test facility are first to demonstrate stable intense CW electron beam with parameters typical for the RHIC e-cooling project (and potentially for eRHIC), second to test novel elements of the ERL (high current CW photo-cathode, superconducting RF cavity with HOM dampers, and feedback systems), and finally to test lattice dependence of stability criteria. Planned diagnostics include position monitors, loss monitors, transverse profile monitors (both optical and wires), scrapers/halo monitors, a high resolution differential current monitor, phase monitors, an energy spread monitor, and a fast transverse monitor (for beam break-up studies and the energy feedback system). We discuss diagnostics challenges that are unique to this project, and present preliminary system specifications. In addition, we include a brief discussion of the timing system.

This introductory course gives an overview of why diagnostics equipment is crucial for running accelerator facilities. Even if significant progress has been made over the last two decades in terms of designing and modelling an accel- erator, model and reality differ all the time. The commissioning stages of a synchrotron light source and the stability of the beam positions are taken as examples. The main orbit disturbances are driven by alignment errors, drifts with temperature, vibrations, timing system jitters. Reaching a high level of stability and beam availability in facilities is very challenging. This is attained by driving forward the equipment performance. This starts off with the design of the building and the girders supporting the equipment, the optimization of magnets, the stability and precisionof the power supply, the diagnostics elec- tronics, and the careful design of the beamlines. In addition, passive and active corrections have to be devised to maintain the highl...