M. Comunian

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Linear IFMIF Prototype Accelerator (LIPAc) Radio Frequency Quadrupole's (RFQ) RF couplers enhancement towards CW operation at nominal voltage

Fusion engineering and design, Jul 1, 2024

Ion transport and gas collision effects in a radio frequency quadrupole cooler: installation in the Eltrap solenoid and beam calculations

Journal of plasma physics, Feb 1, 2024

Stationary-Pic Simulation of High Stability Microwave Discharge Ion Sources

2022 IEEE International Conference on Plasma Science (ICOPS)

Beam Dynamics of the Linac ALPI-PIAVE in View of Possible Upgrades Scenario for the SPES Project

At the Legnaro National Laboratories it is operating a Super Conducting linac for nuclear studies... more At the Legnaro National Laboratories it is operating a Super Conducting linac for nuclear studies named ALPI. The ALPI linac is injected either by a XTU tandem, up to 14 MV, or by the s-c PIAVE injector, made with 2 SCRFQ. In this article will be report the beam dynamics simulations for some possible scenario upgrade of the linac operate by a new injector, made with a new RFQ.

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Commissioning of high current H+/D+ ion beams for the prototype accelerator of the International Fusion Materials Irradiation Facility

Review of Scientific Instruments, 2020

The Linear IFMIF (International Fusion Materials Irradiation Facility) Prototype Accelerator (LIP... more The Linear IFMIF (International Fusion Materials Irradiation Facility) Prototype Accelerator (LIPAc) is aiming at demonstrating the low energy section of a 40 MeV/125 mA IFMIF deuteron accelerator up to 9 MeV with a full beam current in cw operation. For such a high-power beam, the LIPAc injector is required to produce a 100 keV D+ beam with 140 mA and match it for injection into the Radio Frequency Quadrupole (RFQ) accelerator. The injector is designed by CEA-Saclay based on the high intensity light ion source (SILHI). In 2019, the commissioning of the RFQ to demonstrate the D+ beam acceleration at a low duty cycle (0.1%) was conducted. A nominal beam current of 125 mA D+ beam was accelerated up to 5 MeV through the RFQ successfully. The LIPAc injector fully satisfied the requirements for RFQ beam commissioning at the pulse mode.

Analysis of grid size and ion temperature effects in retarding field energy analyzers (RFEA)

AIP Advances, 2018

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IFMIFDynamics-L&PB 2014

High Current Ion Sources, Beam Diagnostics and Emittance Measurement

Singly charged ion sources can easily surpass the 1 kW beam power, as in TRIPS (H + , 60 mA, 80 k... more Singly charged ion sources can easily surpass the 1 kW beam power, as in TRIPS (H + , 60 mA, 80 kV, now in-stalled at LNL) or in NIO1 (H − , 130 mA distributed into 9 beamlets, 60 kV, a project of RFX and INFN-LNL). Beam diagnostic constitutes an important instrument in the high current source development. Even if calorimetric and op-tical beam profile monitors become possible, still a phase space plot of the beam will be the most useful tool for vali-dation of extraction simulation and for input of subsequent beam transport optimization. Improvements in extraction beam simulations are briefly reported, and effect of space charge neutralization is discussed. Since preliminary de-sign of the traditional two moving slit beam emittance me-ter show problems with slit deformations and tolerances and with secondary emission, an Allison scanner was cho-sen with the following advantages: only one movement is needed; data acquisition is serial and signal can have an adequate suppression of s...

ESS Conceptual Design Report

The high intensity spallation neutron source ESS is well set to start construction in 2013 and to... more The high intensity spallation neutron source ESS is well set to start construction in 2013 and to deliver �rst neutrons in 2019. The project itself has been 20 years in gestation but there has been a determination amongst the user community and those working in national and international neutron laboratories in Europe that it would be built. That determination is what has brought the project in where it is today. The baseline speci�cation is for a 5 MW power, long pulse facility delivering neutrons to 22 independent instruments for the study of materials in all their diversity from pharmaceuticals and membranes, to colloids and polymers, to magnetic and superconducting materials, and on to engineering and archeological artefacts. The user community is rich and equally diverse, containing approximately 6000 individuals according to �gures produced by ENSA, the European Neutron Scattering Association. This Conceptual Design Report represents the work of about 250 individual scientists and engineers around Europe and the rest of the world, with about 100 of them located in the central team in Lund in southern Scandinavia where the facility is to be built, with Sweden and Denmark as co-hosts. As this team has grown over the past 2 years, the work intensity and output has risen considerably. It has taken some time for the realisation that ESS is �nally to be built, to be fully digested, but it is clear now that this is indeed accepted. The CDR is a technical document. It does not address organisational matters, nor governance matters and less so �nancial matters, although it must be emphasised that these subjects are borne in mind in arriving at the scope of ESS and hence the speci�cation of the facility. Over the next 12 months, work will be engaged upon which will result in a Technical Design Report being produced together with a series of other documents such as an updated Costing Report. These documents will demonstrate the sound foundation upon which the project is to be constructed and are a necessary, but not su�cient, achievement to lead on seamlessly to construction. Su�ciency would require our 17 partner countries to reach a political and �nancial agreement. We are con�dent that it is within their capabilities and resources to do so, and we look to them for such a signal.

Design study of a re-bunching RFQ for the SPES project

Journal of the Korean Physical Society, 2014

ABSTRACT An upgrade to the 2nd generation of the selective production of exotic species (SPES) to... more ABSTRACT An upgrade to the 2nd generation of the selective production of exotic species (SPES) to produce a radioactive ion beam (RIB) has been studied at the istituto nazionale di fisica nucleare — laboratory nazionali di Legnaro (INFN-LNL). Due to the long distance between the isotope separator online (ISOL) facility and the superconducting quarter wave resonator (QWR) cavity acceleratore lineare per ioni (ALPI), a new re-buncher cavity must be introduced to maintain the high beam quality during the beam transport. A particular radio frequency quadrupole (RFQ) structure has been suggested to meet the requirements of this project. A window-type RFQ, which has a high mode separation, less power dissipation and compact size compared to the conventional normal 4-vane RFQ, has been introduced. The RF design has been studied considering the requirements of the re-bunching machine for high figures of merit such as a proper operation frequency, a high shunt impedance, a high quality factor, a low power dissipation, etc. A sensitivity analysis of the fabrication and the misalignment error has been conducted. A micro-movement slug tuner has been introduced to compensate for the frequency variations that may occur due to the beam loading, the thermal instability, the microphonic effect, etc.

Frequency map analysis for high intensity beams

AIP Conference Proceedings, 1999

The Frequency Map analysis is applied to the Particle-Core model for an intense beam in a FODO ce... more The Frequency Map analysis is applied to the Particle-Core model for an intense beam in a FODO cell. We show that the Frequency Map allows to get an useful picture of the phase space even in the unmatched cases and we point out the importance of the resonances between the betatronic frequencies and the envelope frequencies in the stability problem

CTF developments and results

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Plasma-beam traps and radiofrequency quadrupole beam coolers

Review of Scientific Instruments, 2014

Two linear trap devices for particle beam manipulation (including emittance reduction, cooling, c... more 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.

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A particle-core-MD model for intrabeam scattering and halo formation in high current beams in a FODO channel

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2002

ABSTRACT An essential problem for the successful operation of high current linear ion accelerator... more ABSTRACT An essential problem for the successful operation of high current linear ion accelerators is the control of beam losses due to halo particles. As a possible mechanism for the formation of such a halo we concentrate on the interplay between intrabeam scattering (IBS) and the incidence of particles which are driven to high amplitudes by resonances with the nonlinear space charge fields of a mismatched beam. Since a fully microscopic numerical treatment including all the mutual Coulomb interactions between the beam ions requires much too high computational effort, we developed an approximative method. These particle-core-molecular-dynamics (PCMD) simulations suitably join the mean-field description of the time evolution of the beam in framework of the envelope equations and a microscopic calculation of the Coulomb interactions between pseudo-particles with a renormalized charge. With this method we studied matched and mismatched continuous KV-beams in a FODO channel. In first simulation runs we observed a significant difference in the formation of a cloud of particles around the beam core between matched and mismatched beams when IBS is present. While for a matched beam with IBS no particles with increasing amplitudes have been found, such particles appear at the same IBS rate for a mismatched beam. These results suggest that in a mismatched beam even rather small IBS rates seem to act as a non-negligible source for a halo formation. To conclude from these observations on intense real beams in a high current linac needs, however, further verification of the proposed PCMD method.

CLIC Test Facility developments and results

Proceedings Particle Accelerator Conference

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Istituto Nazionale DI Fisica Nucleare

In this report the theoretical and experimental activities for the development of superconducting... more In this report the theoretical and experimental activities for the development of superconducting microwave cavities for the detection of gravitational waves are presented. Electronic address: gianluca.gemme@ge.infn.it Typeset byREVTEX Published by SIS–Pubblicazioni Laboratori Nazionali di Frascati

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Design of High Resolution Mass Spectrometer for SPES

Within the framework of the SPES (Selective Production of Exotic Species) project at National Ins... more Within the framework of the SPES (Selective Production of Exotic Species) project at National Institute of Nuclear Physics (INFN laboratory, Legnaro, Italy) the High Resolution Mass Spectrometer (HRMS) will be build. HRMS needs to provide full separation of the ions with mass resolution 1/20000 for the following breeding and acceleration on ALPI Linac. In this article the main design choice of the HRMS and of the transport channel will be reported.

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Beam Dynamics of the First Beams for IFMIF-EVEDA RFQ Commissioning

The installation of the IFMIF-EVEDA RFQ, MEBT, LEBT, source and beam dump was completed in Septem... more The installation of the IFMIF-EVEDA RFQ, MEBT, LEBT, source and beam dump was completed in September 2017. The beam dynamics of the first beams for the IFMIF-EVEDA RFQ commissioning is presented. Moreover, a proposal for the CW RFQ steady state commissioning is shown, with a focus on the beam dynamics challenges of the beam transport after the RFQ.

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Beam Dynamics Simulation and Measurements for the IFMIF/EVEDA Project

In the framework of IFMIF/EVEDA project the source and RFQ are ready to be tested with beam. In t... more In the framework of IFMIF/EVEDA project the source and RFQ are ready to be tested with beam. In this article the beam dynamics simulation and the measurement performed in preparation of the first beam injection are presented. The installed line is composed by the proton and deuteron Source with the LEBT composed of two solenoids that inject in the 10 meters long RFQ, the MEBT, diagnostic plate and the beam dump. The line is prepared to be tested with protons of 8 mA in pulsed mode (up to 0.1%).

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A 100 MeV Superconducting Proton Linac: Beam Dynamics Issues

Proton linacs with beam intensities between 10 and 120 mA in CW are under study in various labora... more Proton linacs with beam intensities between 10 and 120 mA in CW are under study in various laboratories, for applications that go from fundamental physics to energy production and nuclear waste transmutation. The majority of the projects consider, for energy above 100 MeV, the use of a superconducting linac, which is particularly convenient for "moderate" currents (10-50 mA). For the low energy part the situation is unclear, and the advantages of a superconducting structure have not been generally recognized yet. In this paper we consider a possible architecture for a 100 MeV linac based on independently phased resonators, and we give a first analysis of the beam dynamics issues, and the resulting cavity specifications. The flexibility of such a linac, for the use with different charge over mass ratios and beam currents, will be underlined.

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