Beam Instrumentation for Exotic Ion Beams

Within the CATHI project for the HIE-ISOLDE upgrade, the group's work currently focuses on the development and implementation of cutting-edge instrumentation to measure the very faint currents that HIE-ISOLDE radioactive ion beams will provide. Study into solid-state detectors (Silicon and Diamond) are being carried out to fulfil the measurement requirements for the sensors, mainly concentrating on radiation hardness.

The properties to be measured are:

  • Beam current. This is essential in order to optimize the transmission. A Faraday cup is the main solution for measuring stable beam currents. Due to the limited longitudinal space available a new design of the Faraday cup is needed, so that its length cannot exceed 20 mm, while the diameter should be 30 mm, covering the full beam.

  • Transverse beam profile. It is roughly a Gaussian bell measured by Profile Monitor configuration, that is, the Faraday cup with a slit scanner in front. The slit scanner has two slits, one horizontal and one vertical. When the slit scanner crosses the beam path, only small beamlets reach the Faraday cup, and then the transverse beam profile is reconstructed automatically.

  • Beam Position. It will be measured using either the slit scanner or  collimator blades, together with the Faraday cup downstream.

  • Emittance. The measurement device is actually comprised of two short diagnostic boxes one after another, at a certain distance, so one slit from the first box will block the beam, and the second one in the last box will scan the profile of that position to get an accurate measurement of the beam’s angular distribution. It is a phase space sampling technique, which allows scientists to know the behavior of the particle beam.

Compact Faraday Cup



Currently involved QUASARs:



Selected publications:

  • S. Aghiona, O. Ahlénc, C. Amslerd,..., J. Harasimovicz,..., A. Sosa,…, C. P. Welsch et al., 'Prospects for measuring the gravitational free-fall of antihydrogen with emulsion detectors', Journal of Instrumentation 8 P08013  (2013) (P08013)
  • A. Sosa, A. Jeff, C.P. Welsch, 'Secondary EMission Monitor for keV Ion and Antiproton Beams', IBIC 2013, Oxford, UK (2013)
  • A Parfenova, P Farantatos, R Mompo, M Timmins, W Andreazza, E Zografos, ED Cantero, AJ Kolehmainen, G Vandoni, J Bauche, A Sosa, D Lanaia, MA Fraser, E Siesling, B Goddard, M Martino, D Voulot, Y Kadi. , 'Design and Performance of the Beam Transfer Lines for the HIE-ISOLDE Project', Proc. IPAC, Shanghai, China (2013).
  • A. Sosa, E. Bravin, M.A. Fraser, .J Galipienzo, Y. Kadi, A. Larman, C. P. Welsch, 'Beam instrumentation for the HIE-ISOLDE linac at CERN',   Proc. IPAC, New Orleans, USA (2012)