Optical Transition Radiation (OTR) is commonly used in imaging systems of highly relativistic charged particle beams as the light yield and collection efficiency would increase with beam energy. For low beam energies, scintillating screens are typically preferred but would saturate or even get damaged when using high beam current. For such a beam, OTR screens can, therefore, still be an attractive diagnostic tool when using thermally resistant materials such as Glassy Carbon. This work presents the OTR based beam imaging measurements of a high-intensity low energy (7keV) hollow electron beam at the Electron Beam Test Stand at CERN. The mechanical design of the monitor as well as the expected OTR angular distribution are presented. Beam images performed with an aluminium oxide scintillating screen are also shown and compared to the OTR results.

Optical Transition Radiation (OTR) is commonly used in imaging systems of highly relativistic charged particle beams as the light yield and collection efficiency increase with beam energy. For low beam energies, scintillating screens are typically preferred but they saturate or even get damaged when using a high beam current. For such a beam, OTR screens can, therefore, still be an attractive diagnostic tool when using thermally resistant materials such as Glassy Carbon. This work presents the OTR-based beam imaging measurements of a high-intensity low energy (7~keV) hollow electron beam at the Electron Beam Test Facility (EBTF) at CERN. The mechanical design of the monitor, as well as the expected OTR angular distribution, are presented. Beam images obtained with an aluminium oxide scintillating screen are also shown and compared to the OTR results. This contribution presents the design of the monitor and discusses the initial results obtained with a hollow electron beam at the EBTF.

A beam profile monitor using gas jet technology is being designed and manufactured at the Cockcroft Institute for high intensity electron beams. It generates a thin, supersonic gas sheet that traverses the beam at a 45-degree orientation and measures the beam-induced fluorescence interactions to produce a 2D beam profile image. The gas sheet acts similar to a scintillating screen, but remains non-invasive. This contribution summarises the method developed towards optimising the injection of a gas jet monitor for the example use-case of the Hollow Electron Lens. A multi-objective genetic algorithm is used with a Monte-Carlo particle tracking simulation to optimise the geometric features of the jet injection chambers. The algorithm optimises for several key features of the jet that will improve it as a diagnostic tool. Specifically, at the point of interaction, the jet’s density, uniformity and geometric dimensions are considered. The work developed in this contribution is not limited to diagnostics and can be expanded upon in other disciplines such as plasma wakefield gas injections.

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.