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Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

The new Bern cyclotron laboratory aims at industrial radioisotope production for PET diagnostics and multidisciplinary research by means of a specifically conceived beam transfer line, terminated in a separate bunker. In this framework, an innovative beam monitor detector based on doped silica and optical fibres has been designed, constructed, and tested. Scintillation light produced by Ce and Sb doped silica fibres moving across the beam is measured, giving information on beam position, shape, and intensity. The doped fibres are coupled to commercial optical fibres, allowing the read-out of the signal far away from the radiation source. This general-purpose device can be easily adapted for any accelerator used in medical applications and is suitable either for low currents used in hadrontherapy or for currents up to a few μA for radioisotope production, as well as for both pulsed and continuous beams.

In the developed countries every 10 million inhabitants about 20′000 oncological patients are irradiated every year with high‐energy photons (called X‐rays by radiotherapists) produced by electron linacs. This is the so called “conventional” radiotherapy. Hadrontherapy is a novel technique of radiotherapy which instead of X‐rays employs beams of charged hadrons, protons and carbon ions in particular. Due to their physical and radiobiological properties, they allow to obtain a more conformal treatment than X‐rays, sparing better the surrounding healthy tissues with a subsequent larger control rate. By now about 40′000 patients have been treated worldwide with protons and 15 hospital based centres are either running or under construction. Carbon ion beams deliver the dose as precisely as protons and are characterized by a larger biological effectiveness than X‐rays and protons. They are therefore particularly suited to treat radio resistant tumours, as proven by the clinical studies performed on about 2′300...

The K0sK0s final state in two-photon collisions is studied with the L3 detector at LEP using data collected at centre-of-mass energies from 91 GeV to 202 GeV. The mass spectrum is dominated by the formation of the f_2'(1525) tensor meson in the helicity two state. The two-photon width times the branching ratio is measured to be Gamma_{gamma gamma}(f_2'(1525))Br(f_2'(1525)->KKbar) = 0.076 +- 0.006 +- 0.011 keV. Clear evidence for destructive f_2(1270)-a_2(1320) interference is observed. In addition a clear signal for f_J(1750) is observed. The study of the decay angular distribution in the 1750 MeV mass region shows that the spin two helicity two wave is dominant. No signal is observed in the region around 2.2 GeV. The upper limit for the two-photon partial width of the \xi(2230) tensor glueball candidate of Gamma_{gamma gamma}(\xi(2230))Br(\xi(2230)->K0sK0s)