Development of a silicon detector monitor for the HIE-ISOLDE superconducting upgrade of the REX-ISOLDE heavy-ion linac

A silicon detector monitor has been developed and tested in the framework of the beam diagnostics development program for the HIE-ISOLDE superconducting upgrade of the REX-ISOLDE heavy-ion linac at CERN. The monitor is intended for beam energy and timing measurements aimed at the phase tuning of the superconducting cavities. Tests were performed with a stable ion beam, composed of carbon, oxygen and neon ions accelerated to energies from 300keV/u to 2.82MeV/u. The energy measurements performed allowed for beam spectroscopy and ion identification with a resolution of 1.4%-0.5% rms in the measured energy range. The achieved resolution is suited for a fast phase tuning of the cavities, which was demonstrated with the third REX 7-gap resonator. The time structure of the beam, characterised by a bunch period of 9.87ns, was measured with a resolution better than 200ps rms. This paper describes the results from all these tests and provides details of the detector set-up.