An electron beam test stand was designed and constructed at CERN, under the umbrella of the Hi-Lumi project, to tests components for the Hollow Electron Lens (HEL), and in collaboration with the ARIES project for testing the Space Charge Compensation gun. The test facility features normal conductive magnets providing solenoid fields of the order of fractions of Tesla, beam diagnostics including screens (YAG, Cromox and OTR) for the full electron beam characterisation, a Faraday Cup collector to measure the total electron current, and a high voltage power supply up to 40 kV (with the possibility of biasing both gun and collector). It offers the possibility of testing high current and high perveance guns, different beam instrumentation (Beam Position Monitors and Beam Gas Curtain monitors are some examples), electron collectors, and beam pulse modulators. In this paper the facility is described and the first results validating the design of the HEL gun are presented.

The Hollow Electron Lens (HEL) was proposed to actively remove the beam halo of the proton beam for the HL-LHC upgrade. Currently, the concept of generating such an electron beam is being tested in a dedicated Electron Beam Test Stand (EBTS) at CERN. It currently produces a hollow electron beam with 7 keV energy and 0.4 A current 25 us pulsed with 2 Hz which will be confined in a strong solenoid field. A gas curtain-based beam profile monitor was developed to characterize the beam non-invasively during operation. It injects a directional gas sheet at 45 degrees to interact with the electron beam. Gas particles are excited and emit fluorescent photons which are collected by an intensified camera system. This allows the reconstruction of the profile of the hollow electron beam. This contribution presents the design of the monitor and discusses the initial results obtained with a hollow electron beam at the EBTS.