S. Passarello

Enhancement of ion current from the TRIPS source by means of different electron donors

A series of measurements were carried out with the TRasco Intense Proton Source (TRIPS) to determine the effectiveness of different materials as electron donors. It is well known that the use of boron nitride (BN) disks inside the plasma chamber increases the current extracted from microwave discharge ion sources, generating additional electrons. In the past, one of the two disks was replaced by a 40μm Al2O3 coating over the extraction electrode, which gave some increase of current, but after less than 200h was heavily damaged. The tests here reported concern three different options: (a) thicker Al2O3 layer (100μm) deposited over the extraction electrode; a 1-mm-thick aluminium foil over which an alumina layer is deposited, inserted in the plasma chamber; a 5-mm-thick Al2O3 tube embedded in the plasma chamber of the TRIPS source (the outer diameter of the tube being slightly smaller than the inner diameter of the chamber). The tests were carried out in the same conditions as for magnetic field topology an...

ELIMED a new concept of hadrontherapy with laser-driven beams

ELIMED (Medical Applications at Extreme Light Infrastructure) is a task-force originally born by an idea of ELI-Beams (Prague, CZ)and INFN-LNS (Italian Institute for Nuclear Physics of Catania, I) researchers. It now involves other groups interested in the possibility to design and develop a new generation of hadrontherapy facilities using laser-accelerated ion beams. ELIMED main goal is to perform proof-of-principle experiments aimed to demonstrate that laser-accelerated high-energy proton beams (up to 70 MeV in the first phase) can be potentially used for the specific case of ocular proton therapy. For this purpose new devices for beam handling and transport will be developed as well as new methods for radiobiology and dosimetry. The involvement of INFN-LNS group takes advantage of the well-established expertise in dosimetry measurements and Monte Carlo calculations for medical physics, which has been achieved in several years of eye tumor treatments in the CATANA proton therapy facility. Recently, in the framework of an INFN activity, they have also designed, fabricated, calibrated and experimentally tested at PALS laser laboratory (Cz) a Thomson Parabola ion spectrometer with a wide acceptance and able to characterize laser-driven proton beams up to 20 MeV.

Status Of The EXCYT Facility at INFN‐LNS

The EXCYT facility (EXotics with CYclotron and Tandem) at the INFN‐LNS is based on a K‐800 Superconducting Cyclotron injecting stable heavy‐ion beams (up to 80 MeV/amu, 1 eμA) into a target‐ion source assembly to produce the required nuclear species, and on a 15 MV Tandem for post‐accelerating the radioactive beams. Since December 1999 the Superconducting Cyclotron operates in a stand‐alone mode by means of the new axial injection beam line. The primary beam line has been already mounted and tested. The part of mass separator on the two high‐voltage platforms together with low intensity diagnostics is already installed while the ancillary items along with the part of mass separator at ground potential will be installed during the next stop of accelerator operations. The target‐ion source unit has been successfully tested on‐line at GANIL. The goal of such efforts will be represented by the test of the mass separator with stable beams planned at LNS by the end of the year. The commissioning of the EXCYT fa...

Electrostatic Deflectors: New Design for High Intensity Beam Extraction

During the last years big effort was devoted to increase the electrostatic deflectors’ reliability; this provided a better comprehension of the most significant effects concerning their working conditions. Deflectors were checked during the normal operation of the K800 Superconducting Cyclotron (CS) at LNS, at the operating pressure of 1 10-6mbar and a magnetic field of 3.5 T, the maximum cathodes voltage was – 60kV (120 kV/cm). The maximum extracted beam power was, up to now, 100 W; it is foreseen to extract up to 500 W. In this contribution we present the study, the tests and the design of a new water cooled electrostatic deflector. Particular effort was applied to optimise the beam extraction efficiency, the thermal dissipation, and the mechanical stability. In particularly we implemented new insulators, new anodised aluminium cathodes, new Ta septum, new voltage and water feedthroughs and a more efficient cooling system. All these improvements were performed to increase the mean time between failure and the beam current stability.