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12
NEW PROTON IRRADIATION FACILITY IN PROSCAN AREA
W. Hajdas, R.Brun, K.Egli (PSI), R.Harboe-Sorensen, A.Mohamadzadeh, R.De Marino (ESA-ESTEC)
New Proton Irradiation Facility PIF test site was installed in the experimental area of the PROSCAN biomedical
accelerator. First protons were delivered in September 2008 and since then several test and exposure runs were
successfully conducted. Primary beam energies can be set between 70 and 250 MeV. Further reduction down to few
MeV is possible with a local degrader. Beam profiles can be adjusted to uniformly cover targets with areas of tens
cm2. Beam intensities of up to 10 nA allow for efficient irradiations by both space and particle physics communities.
The new exposure site of the PIF facility has been installed
in the experimental area of the PROSCAN biomedical
accelerator – see Fig. 1. The area has been commissioned in
August 2008 and first beam have been successfully
delivered in September. Experimental setup for PIF
irradiations is arranged in a similar manner as in the low
energy site in the NEB area. This way, the former facility
users can conduct their standard tests without any
additional modifications. Moreover the beam line itself has
been equipped with new, more advanced diagnostics like
extra profile and current monitors. The experimental setup
consists of a large bench with a local dosimetry block and a
user frame fixed on the XY-table. A laser aligned with the
beam line axis is mounted at the rear side of the bench. The
beam dump is located directly in the area wall. The
dosimetry block consists of two flat, air filled ionization
chambers ICs and the XY wire chamber WC for monitoring
of the beam intensity and profiles. A local energy degrader
made of 7 Cu-plates of various thicknesses is placed
between the chambers – see Fig. 2. The degrader allows for
a quasi continuous setting of the energy on target down to
ca. 10 MeV. Both setting of the energy with the degrader
based on the SRAM memory. The SUE monitor was
provided for PIF by the European Space Agency ESA – the
main user of the facility.
Fig. 2: Dosimetry block (ICs, WC) and energy degrader.
Fig. 3: Plastic scintillator detectors on DUT frame.
Fig. 1: Location of the PIF facility at PROSCAN.
and positioning of the user device under test DUT with the
XY-table are remotely controlled from the PIF
measurement barrack that is located on the roof of the
experimental area. Calibrations of the beam intensity
measured by the ionization chambers are performed using
small plastic scintillator detectors of precisely know area.
The detectors are mounted exactly at the position of DUT
and count single protons passing through the scintillator –
see Fig. 3. Calibration runs are performed before starting
the DUT exposures at low beam intensity for all energies
used in the experiment. Further verification of the proton
flux is possible with a Single Event Upset SEU Monitor
Initial energies of protons entering the area can be set
between 70 and 250 MeV. Beam optics setups available to
date exist for energies of 235, 200, 150, 100 and 70 MeV.
They are optimized for both wide and narrow field beams at
DUT with FWHM between 60 and 6 mm respectively.
Maximum beam intensities allowed for the PIF site are 2
nA for energies above 200 MeV and 10 nA for energies
below 100 MeV. The intensity can be remotely set from the
operating console in the PIF barrack. As the day shifts are
reserved for biomedical applications, the facility runs either
during the late and night shifts or at weekends. Beam setup
and its diagnostic are user friendly and can be performed
locally. First tests also showed both high quality of the
beam and stability of the beam-line settings. It should
assure reliable exposures and large number of users tests.