Status of and Future Plans for the CERN LINAC4 Emittance Meter based on Laser Electron-Detachment and a Diamond Strip-Detector

Thomas Hofmann, Enrico Bravin, Uli Raich, Federico Roncarolo, Francesca Zocca, Gary Boorman, Alessio Bosco, Stephen Gibson, Konstantin Kruchinin, E. Griesmayer

Research output: Chapter in Book/Report/Conference proceedingConference contribution


LINAC4 has started its staged commissioning at CERN. After completion it will accelerate high brightness H− beams to 160 MeV. To measure the transverse profile and emittance of the beam, a non-destructive method based on electron photo-detachment is proposed, using a pulsed, fibre-coupled laser to strip electrons from the H− ions. The laser can be focused and scanned through the H− beam, acting like a conventional slit. A downstream dipole separates the neutral H0 beamlet, created by the laser interaction, from the main H− beam, so that it can be measured by a diamond strip-detector. Combining the H0 beamlet profiles with the laser position allows the transverse emittance to be reconstructed. A prototype of this instrument was tested while commissioning the LINAC4 at 3 and 12 MeV. In this paper we shall describe the experimental setup, challenges and results of the measurements, and also address the characteristics and performance of the diamond strip-detector subsystem. In addition, the proposal for a permanent system at 160 MeV, including an electron detector for a direct profile measurement, will be presented.
Original languageEnglish
Title of host publication3rd International Beam Instrumentation Conference
Subtitle of host publicationMonterey, CA, USA, September 14-18, 2014.
ChapterBeam Profile Monitors
Number of pages5
ISBN (Electronic)978-3-95450-141-0
Publication statusPublished - 18 Sept 2014

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