Abstract
Abstract
The Super-FRS at the FAIR accelerator complex will adopt Chemical
Vapor Deposition diamond detectors as radiation-hard particle rate
counters.
Their role will be to monitor the beam transmission for beams
with ions rates up to 107 ions/spill and to calibrate the other
beam diagnostics devices that are in duty at higher beam
intensities.
The target vacuum chamber of the Super-FRS hosts a 7 × 7 mm2 single crystal diamond and a 25 × 25 mm2 polycrystalline
diamond: they are required to detect crossing particles with high
efficiency (> 98%) in the case of heavy ion species (Ar to U), and
to stand for several years in an environment in which they can
potentially accumulate a dose of a few MGy per year.
Laboratory measurements and beam test campaigns were arranged in the
past years for the validation of the proposed sensors, in particular
for the case of the polycrystalline technology.
Here we report the outcome of the irradiation of a sensor based on a
20 × 20 mm2 polycrystalline diamond produced by Element
Six, with high intensity 1 GeV/nucleon Pb and U beams at GSI
(Darmstadt). The detector signal shape characteristics and the ion
counting efficiency have been monitored by interleaving periods of low
ions rates, to evaluate possible damages or performance degradation
during and after a total bombardment of about 6 × 1011 heavy ions.