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Paul Scherrer Institut

Proton Irradiation Facility at Laboratory For Particle Physics    

Paul Scherrer Institut

CH-5232 Villigen PSI

Phone +41 56 310 21 11

Fax +41 56 310 21 99








 PIF Group Home

 PIF Home


 Experimental Site

 Main Features

   Sample Frame



  Beam Order

   Proton Tests 

   Electron Tests

  Some Essentials

  Useful Links

  Annual Reports



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E-Mail: wojtek.hajdas@psi.ch

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High Energy Site

Experimental Site

The initial proton beam for PIF is delivered from the PROSCAN accelerator with 
the help of the primary energy degrader, which allows setting the initial beam energy
from 230 MeV down to 74 MeV. The beam is subsequently guided to the Experimental
Area where PIF facility is located. 
Having energy of the beam degraded directly after accelerator exit causes also
its intensity reduction on target. 
Additional safety reasons put the maximum beam intensity in the PIF area up to
2 nA for energies above 200 MeV, 5 nA for energies from 100 MeV to 200 MeV and
10 nA for energies below 100 MeV.   As PROSCAN accelerator serves also two GANTRY stations
and OPTIS2 facility for the cancer treatment, most of PIF exposures are conducted
during weekends and short night-shifts.

The PIF experimental area is located in the PROSCAN accelerator Hall as showed in the Figure below.

Figure 1. PIF-PROSCAN Hall with the PIF Experimental Area.

PIF area is equipped with the beam-line elements and PIF arrangement as showed below (Photo 1).


Photo 1. PIF area downstream view with the last quadrupole magnets, beam monitors and PIF station. One can see the XY-table with beam collimator.

The PIF experimental set-up consists of the local PIF energy degrader, beam collimating 
and monitoring devices (Photo 2).

Photo 2. PIF arrangement with the ionization chamber, energy degrader and wire chamber.

Movable XY table with the sample holder (see Photo 3) enables easy mounting of the
user's device under test (DUT) on the beam. 

Photo 3. PIF arrangement rear view with the XY-table, its movable arm and DUT sample holder.

The laser mounted downstream from the XY table allows centering the DUT and control 
its position (see Photo 4).

Photo 4. PIF area downstream view with the laser for sample centering and the beam dump. 

Irradiations are usually carried out in air. The maximum available energy is 230 MeV and the 
maximum current is limited to about 2 nA due to air activation in the experimental area.

According to the experience and user requirements, the monitor detectors are selected for each
experiment individually: ionization chambers, Si-detectors, plastic scintillators. In addition, the gamma and neutron dosimetry is routinely performed (see Photo 5 below).

Photo 5. PIF area neutron and gamma dosimeters.

Schematic view of the experimental hall from the point of view of beam-lines and area locations is shown in Figure below:

Figure 2. PROSCAN Hall, accelerator, beam-lines and tests areas. PIF site is marked as ‘EXP.’.

The irradiation is controlled from the experimental barrack located on top of the PIF area (see Photo below).

Photo 6. PIF operator table in the barrack.

Beam flux values are monitored through a set of counters and a PC-based data acquisition system. 
The system monitors proton flux and dose rate, calculates the total deposited dose and 
controls the position of the sample as well as beam focus parameters. It also allows for 
setting the beam energy with the help of the PIF local energy degrader. This makes it
possible  to perform fully automated irradiations with arbitrary proton spectra.

Photo 7. One of the users tables.

The experimenters have for their use and needs of their data test setup the second part of the PIF barrack as seen on the Photo above. Standard laboratory and electronic equipments is also available.

Main Features

·         Initial proton energies: 230, 200, 150, 100 and 74 MeV
(can be modified if requested)

·         Energies available using the PIF degrader:
quasi continuously from 6 MeV up to 230 MeV

·         Energy straggling for the initial beam energy of 74.3 MeV:
e.g. FWHM=2.4 MeV at 42.0 MeV, FWHM=5.6 MeV at 13.3 MeV.

·         Maximum beam intensity at 230 MeV: 2 nA (at 74.5 MeV ca. 5 nA effectively)

·         Maximum flux at 230 MeV for the focused beam:
~ 2*109 protons/sec/cm2

·         Beam profiles are of Gaussian-form with standard (typical):
FWHM=10 cm

·         Irradiations take place in air

·         The maximum diameter of the irradiated area: f 9 cm

·         The accuracy of the flux/dose determination: 5%

·         Neutron background: less than 10-4 neutrons/proton/cm2

·         Irradiations, devices and sample positioning are supervised by the computer

·         Sample mounting frame 25 x 25 cm2 (SEU and HIF facilities compatible)
is attached to the XY table

·         Data acquisition system allows automatic runs with user pre-defined
irradiation criteria