Abstract
Hollow Electron Lenses (HEL) will be installed at the High Luminosity Large Hadron Collider to provide a continuous and controlled depletion of beam halo particles by interaction with a superimposed hollow electron beam, of intensity as high as 5 A, and radii 1.1–2.2 mm for 7 TeV LHC operations. In this paper, issues related to the propagation of high intensity hollow electron beams are discussed and the simulations of the electron beam dynamics with feedback to the HEL design are presented. The main results are the rise of the electron beam accelerating voltage from 10 kV, as in the initial proposal, to 15 kV and the validation of the 5 T magnetic field at the main solenoids as being sufficient to guarantee a stable electron beam.
Highlights
Hollow Electron Beam main parametersAt the Hollow Electron Lenses (HEL), the 5 A electron beam is generated by thermionic effect at an annular Scandium doped dispenser [12] (called hereafter cathode), heated to about 900◦C
Collider to provide a continuous and controlled depletion of beam halo particles by interaction with a superimposed hollow electron beam, of intensity as high as 5 A, and radii 1.1–2.2 mm for 7 TeV
Issues related to the propagation of high intensity hollow electron beams are discussed and the simulations of the electron beam dynamics with feedback to the Hollow Electron Lenses (HEL)
Summary
At the HEL, the 5 A electron beam is generated by thermionic effect at an annular Scandium doped dispenser [12] (called hereafter cathode), heated to about 900◦C. For easiness of operation of the HEL, only the field at the cathode will be controlled, leaving all other magnets at constant current (or field) The drawback of this choice is that in the present configuration, optimised for operation at nominal LHC beam energy (7 TeV), is not suited to work at LHC beam at injection energy (450 GeV). Given a maximum magnetic field at the mains of 5 T, a maximum field at the cathode of 4 T, and cathode raddi equal to 4.02–8.05 mm, the largest electron beam size achievable in the interaction region will be of 3.6–7.2 mm, which is smaller than the LHC beam at injection energy (450 GeV). The expected beam shape evolution through the gap is shown in figure 3
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
