JINST Instrumentation Theses Archive

Ph.D. degree thesis
accepted by Universit� Claude Bernard Lyon I, Institut de Physique Nucl�aire, France and Fondazione TERA, Italy, in 2005

Paolo Berra

Supervisors: Ugo Amaldi, Albert Demeyer and Joseph Remillieux

Design, construction and tests of a 3 GHz proton linac booster (LIBO) for cancer therapy

 Keywords:

• Instrumentation for particle accelerators and storage rings - high energy (linear accelerators, synchrotrons)
• Instrumentation for hadron therapy
• Acceleration cavities and magnets superconducting (high-temperature superconductor; radiation hardened magnets; normal-conducting; permanent magnet devices; wigglers and undulators)

 Abstract:
In the last ten years the use of proton beams in radiation therapy has become a clinical tool for treatment of deep-seated tumours. LIBO is a RF compact and low cost proton linear accelerator (SCL type) for hadrontherapy. It is conceived by TERA Foundation as a 3 GHz Linac Booster, to be mounted downstream of an existing cyclotron in order to boost the energy of the proton beam up to 200 MeV, needed for deep treatment (~25 cm) in the human body. With this solution it is possible to transform a low energy commercial cyclotron, normally used for eye melanoma therapy, isotope production and nuclear physics research, into an accelerator for deep-seated tumours. LIBO is also naturally very suitable for the spot scanning techniques now in use in hadrontherapy for the beam delivery to the tumour.

A prototype module of LIBO has been built and successfully tested with full RF power at CERN and with proton beam at INFN Laboratori Nazionali del Sud (LNS) in Catania, within an international collaboration between TERA Foundation, CERN, the Universities and INFN groups of Milan and Naples.

As a consequence of these tests we prove, for the first time, that it is possible to inject and accelerate proton beams from a cyclotron into a 3 GHz linear accelerator. The prototype construction proves also that standard technology can be adopted for fabrication, covering at the same time the stringent physical performances of a compact linac for hadrontherapy. A final accelerating gradient of 29 MV/m has been then reached, so even better than the design value of 15.3 MV/m. The mid-term aim of the project is the technology transfer of the accumulated know-how to a consortium of companies and to bring this novel medical tool to hospitals. The design, construction and tests of the LIBO prototype are described in detail.