M. Maggiore

Plasma-beam traps and radiofrequency quadrupole beam coolers

Two linear trap devices for particle beam manipulation (including emittance reduction, cooling, control of instabilities, dust dynamics, and non-neutral plasmas) are here presented, namely, a radiofrequency quadrupole (RFQ) beam cooler and a compact Penning trap with a dust injector. Both beam dynamics studies by means of dedicated codes including the interaction of the ions with a buffer gas (up to 3 Pa pressure), and the electromagnetic design of the RFQ beam cooler are reported. The compact multipurpose Penning trap is aimed to the study of multispecies charged particle samples, primarily electron beams interacting with a background gas and/or a micrometric dust contaminant. Using a 0.9 T solenoid and an electrode stack where both static and RF electric fields can be applied, both beam transport and confinement operations will be available. The design of the apparatus is presented.

Design of the ELIMAIA ion collection system

A system of permanent magnet quadrupoles (PMQs) is going to be realized by INFN-LNS to be used as a collection system for the injection of laser driven ion beams up to 60 MeV/u in an energy selector based on four resistive dipoles. This system is the first element of the ELIMED (ELI-Beamlines MEDical and Multidisciplinary applications) beam transport, dosimetry and irradiation line that will be developed by INFN-LNS (It) and installed at the ELI-Beamlines facility in Prague (Cz). ELIMED will be the first users open transport beam-line where a controlled laser-driven ion beam will be used for multidisciplinary researches. The definition of well specified characteristics, both in terms of performances and field quality, of the magnetic lenses is crucial for the system realization, for the accurate study of the beam dynamics and for the proper matching with the magnetic selection system which will be designed in the next months. Here, we report the design of the collection system and the adopted solutions in order to realize a robust system form the magnetic point of view. Moreover, the first preliminary transport simulations are also described.

Diagnostic for the radiotherapy use of laser-accelerated proton beams

A research project, LILIA (Laser Induced Light Ion Acceleration), has been funded at INFN (Italian Institute for Nuclear Physics) with the aim of studying the mechanisms of charged particle acceleration by high power lasers. In Italy, at LNF–INFN of Frascati, a high power laser (intensity in the range 1020–1021 W/cm2, 10 Hz repetition rate and high contrast, of the order of 1010, between main pulse and pre-pulse) named FLAME will be operative within 2010. The activities related to this project, along with the FLAME peculiarities, will result in a significant synergy to improve research on plasma acceleration in Italy. In this frame our group is involved in the design and construction of a spectrometer, based on the Thomson configuration, in order to diagnose the ion ejection from the laser-generated plasma. This kind of analyzer allows retrieval of most of the information regarding the energy and species of beams produced from a single laser shot.The main goal is to realize a compact system which is both very practical and optimized with regards to the mass and energy resolution of particles obtained by laser-plasma interactions. The preliminary design has to be able to analyze and resolve beams of protons and ions up to a total energy of 10 MeV. However, the technical choices adopted in this prototype have to be applied in the final device, which concerns a challenging spectrograph able to analyze beams of 150 MeV of total energy. An intensive study by means of 3D electromagnetic FEM code and beam dynamics was accomplished, and the results will be shown. The first prototype of the spectrometer is being realized and tested at LNS–INFN of Catania (Italy). After magnetic and electric measurements, the device will be calibrated, and the detectors will be tested with proton and carbon beams delivered by the accelerators operating at LNS–INFN of Catania within the expected energy range (0.1–10 MeV) and for different charge-to-mass ratios (Q=+1 to+6). The results of these tests will also be presented and discussed.

ELIMED, MEDical and multidisciplinary applications at ELI-Beamlines

ELI-Beamlines is one of the pillars of the pan-European project ELI (Extreme Light Infrastructure). It will be an ultra high-intensity, high repetition-rate, femtosecond laser facility whose main goal is generation and applications of high-brightness X-ray sources and accelerated charged particles in different fields. Particular care will be devoted to the potential applicability of laser-driven ion beams for medical treatments of tumors. Indeed, such kind of beams show very interesting peculiarities and, moreover, laser-driven based accelerators can really represent a competitive alternative to conventional machines since they are expected to be more compact in size and less expensive. The ELIMED project was launched thanks to a collaboration established between FZU-ASCR (ELI-Beamlines) and INFN-LNS researchers. Several European institutes have already shown a great interest in the project aiming to explore the possibility to use laser-driven ion (mostly proton) beams for several applications with a particular regard for medical ones. To reach the project goal several tasks need to be fulfilled, starting from the optimization of laser-target interaction to dosimetric studies at the irradiation point at the end of a proper designed transport beam-line. Researchers from LNS have already developed and successfully tested a high-dispersive power Thomson Parabola Spectrometer, which is the first prototype of a more performing device to be used within the ELIMED project. Also a Magnetic Selection System able to produce a small pencil beam out of a wide energy distribution of ions produced in laser-target interaction has been realized and some preliminary work for its testing and characterization is in progress. In this contribution the status of the project will be reported together with a short description of the of the features of device recently developed.

Calibration and energy resolution study of a high dispersive power Thomson Parabola Spectrometer with monochromatic proton beams

A high energy resolution, high dispersive power Thomson Parabola Spectrometer has been developed at INFN-LNS in order to characterize laser-driven beams up to 30- 40 MeV for protons. This device has parallel electric and magnetic field to deflect particles of a certain charge-to-mass ratio onto parabolic traces on the detection plane. Calibration of the deflection sector is crucial for data analysis, namely energy determination of analysed beam, and to evaluate the effective energy limit and resolution. This work reports the study of monochromatic proton beams delivered by the TANDEM accelerator at LNS (Catania) in the energy range between 6 and 12.5 MeV analysed with our spectrometer which allows a precise characterization of the electric and magnetic deflections. Also the energy and the Q/A resolutions and the energy limits have been evaluated proposing a mathematical model that can be used for data analysis, for the experimental set up and for the device scalability for higher energy.

Design of a large acceptance, high efficiency energy selection system for the ELIMAIA beam-line

A magnetic chicane based on four electromagnetic dipoles is going to be realized by INFN-LNS to be used as an Energy Selection System (ESS) for laser driven proton beams up to 300 MeV and C6+ up to 70 MeV/u. The system will provide, as output, ion beams with a contrallable energy spread varying from 5% up to 20% according to the aperture slit size. Moreover, it has a very wide acceptance in order to ensure a very high transmission efficiency and, in principle, it has been designed to be used also as an active energy modulator. This system is the core element of the ELIMED (ELI-Beamlines MEDical and Multidisciplinary applications) beam transport, dosimetry and irradiation line that will be developed by INFN-LNS (It) and installed at the ELI-Beamlines facility in Prague (Cz). ELIMED will be the first users open transport beam-line where a controlled laser-driven ion beam will be used for multidisciplinary research. The definition of well specified characteristics, both in terms of performance and field quality, of the magnetic chicane is crucial for the system realization, for the accurate study of the beam dynamics and for the proper matching with the Permanent Magnet Quadrupoles (PMQs) used as a collection system already designed. Here, the design of the magnetic chicane is described in details together with the adopted solutions in order to realize a robust system form the magnetic point of view. Moreover, the first preliminary transport simulations are also described showing the good performance of the whole beam line (PMQs+ESS).

Errors and optics study of a permanent magnet quadrupole system

Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines [1]. Nowadays, energy and angular spread of the laser-driven beams are the main issues in application and different solutions for dedicated beam-transport lines have been proposed [2,3]. In this context a system of permanent magnet quadrupoles (PMQs) is going to be realized by INFN [2] researchers, in collaboration with SIGMAPHI [3] company in France, to be used as a collection and pre-selection system for laser driven proton beams. The definition of well specified characteristics, both in terms of performances and field quality, of the magnetic lenses is crucial for the system realization, for an accurate study of the beam dynamics and the proper matching with a magnetic selection system already realized [6,7]. Hence, different series of simulations have been used for studying the PMQs harmonic contents and stating the mechanical and magnetic tolerances in order to have reasonable good beam quality downstream the system. In this paper is reported the method used for the analysis of the PMQs errors and its validation. Also a preliminary optics characterization is presented in which are compared the effects of an ideal PMQs system with a perturbed system on a monochromatic proton beams.

Beamline design for the transport of high intensity beams

Abstract At Laboratorio Nazionale del Sud high beam intensity tests have been carried out for xenon ion beams with the superconducting electron cyclotron resonance source SERSE. These tests confirmed the need to review the main concepts of the beam extraction analysis and transport when high currents of low energy beams are produced. It was demonstrated that the transport of low energy beams and the injection in the cyclotron becomes critical as soon as the extracted current exceeds a few milliamperes. The paper describes the main features of the GyroSERSE source, which is an upgraded version of the SERSE source, and the KOBRA-3D calculations carried out to obtain relatively low emittance beams. The study of the analysis beamline with the GIOSP code is also presented.

The charge breeder beam line for the selective production of exotic species project at INFN-Legnaro National Laboratoriesa)

SPES (Selective Production of Exotic Species) is an INFN (Istituto Nazionale di Fisica Nucleare) project with the aim at producing and post-accelerating exotic beams to perform forefront research in nuclear physics. To allow post-acceleration of the radioactive ions, an ECR-based Charge Breeder (CB) developed on the basis of the Phoenix booster was chosen. The design of the complete beam line for the SPES-CB will be described: a system for stable 1+ beams production was included; special attention was paid to the medium resolution mass spectrometer after the CB to limit possible superposition of the exotic beams with the impurities present in the ECR plasma.

The Energy Selection System for the laser-accelerated proton beams at ELI-Beamlines

ELI-Beamlines is one of the four pillars of the ELI (Extreme Light Infrastructure) pan-European project. It will be an ultrahigh-intensity, high repetition-rate, femtosecond laser facility whose main goals are the generation and applications of high-brightness X-ray sources and accelerated charged particles. In particular medical and multidisciplinary applications with laser-accelerated beams are treated by the ELIMED task force, a collaboration between different research institutes. A crucial goal for this network is represented by the design and the realization of a transport beamline able to provide ion beams with suitable characteristics in terms of energy spectrum and angular distribution in order to perform dosimetric tests and biological cell irradiations. A first prototype of transport beamline has been already designed and some magnetic elements are already under construction. In particular, an Energy Selector System (ESS) prototype has been already realized at LNS-INFN. This paper reports about the studies of the ESS properties as, for instance, energy spread and transmission efficiency, carried out using the GEANT4 Monte Carlo code.