Laura Monaco - Overview on accelerator activities of the INFN Milano LASA SRF Group
10 Nov 2023
The Superconducting RF group at Laboratorio Acceleratori e Superconduttività Applicata (LASA) of INFN Milano started its activities in the 90’s. As founder of the TESLA collaboration, we actively participated in the Tesla Test Facility, contributing to the high brightness electron source with Cs2Te photocathodes, SRF cavities, cryomodule, cryomodule diagnostic and ancillaries. We then enlarged our competences to proton SRF cavities in different projects from the Italian TRASCO, the European ADS program to the design of the American SNS cavities. Thanks to all these competences, we made a further step forward and we joined European XFEL as co-leader of the 1.3 GHz cavities series production, cryomodules and tuners. In the Eu-XFEL context, we also designed, produced, installed, and commissioned a fully operational 3.9 GHz cryomodule, the first module in operation in the whole linac. The know-how on cavity design, prototyping, and testing has been then applied to the In-Kind contribution to the ESS project and, recently, to the PIP-II project where medium and low beta SRF cavities for proton have been required. Concurrently, we have continued the activities on photocathodes developing systems for the photocathode production, transport, and installation in the major high brightness user facilities worldwide. The INFN plug is becoming recognized worldwide as a standard and the performance of the Cs2Te, with lifetime up to 4 years in user operation make them the state-of-the-art reference for the photocathode community.
The talk will provide an overview of the main competences, achievements, and experiences of the SRF group, describing our activities both in the R&D and production fields, with a look at future activities as well.
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Lorenzo Neri - PIC modeling proton sources
13 ott 2023
The requirements for future accelerator chains need to increase the injected beam brilliance significantly, still keeping high the beam quality in terms of reliability, reproducibility and stability. A roadmap for ion source development may consist of several steps: plasma simulation, multiphysics simulation of each system component, high-level control system, plasma characterisation, beam characterisation, data analysis and, again, plasma simulation. The cycle starts and ends with plasma simulation because it is the instrument that shows how different phenomena take part in the plasma and beam formation and because, in such a way, the accuracy grows with each cycle. Commercial multiphysics simulation tools are essential for adequately designing all ion source equipment: magnets, intense electrostatic field regions, microwave propagation and coupling, thermal dissipation and vacuum. The dependence of source performances from source parameters (magnetic field profile, gas pressure, microwave power) has been widely investigated using a high-level control system* able to test tens of thousands of source configurations without human interaction. This kind of characterisation allowed us to identify a new magnetic configuration, High Stability Microwave Discharge Ion Sources**, that produces a beam with high stability, intensity and brilliance. The plasma simulation tool we developed discloses the role of two types of electrostatic waves in plasma formation and their correlation to stability. The simulation provides a complete view of ions and electrons energy and density distributions, the formation of the plasma meniscus and the beam extraction. The paper will present the results obtained with this development procedure on Microwave Discharge Ion Sources and how we started to apply it to the Electron Cyclotron Resonance Ion Sources development.
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Luca Serafini - Large recoil, symmetric photonic colliders, a way towards ultra-low emittance positron beams and intrinsically mono-chromatic gamma-ray beams
14 luglio 2023
We illustrate the generation of secondary particle beams in electron/photon collisions with various set-ups, going from synchrotron radiation (electron - virtual photon collision, i.e. negligible recoil) towards Inverse Compton Scattering at very large recoil, showing that the statistical properties of secondary beams (bandwidth, emittance) greatly benefit from peculiar effects of large recoil collisions, mainly connected to the slowing down of the center of mass reference system movement in the laboratory, that in turns is associated to lowering the Lorentz boost applied to the secondary beam. Exploiting such a property, we can study the generation of ultra-low emittance positron beams and/or very
small bandwidth X/g ray beams (the case of muon beams was discussed in a previous seminar of this series). Furthermore, we recently found a particular mode of electron-photon collisions that we named Symmetric Compton Scattering: it is characterised by a steady center of mass system and it represents exactly the divide between Inverse Compton Scattering and Direct Compton effect (that one discovered by A. Compton in 1923 and explained by him invoking the quantum nature of light, i.e. the existence of photons). SCS is the only electron-photon collision characterised by a vanishing correlation between the energy of the scattered photons and their scattering angle: such a property, when SCS occurs at large recoils, transfers mono-chromaticity from the incident electron beam to the scattered photon beam, opening the way to the generation of mono-chromatic gamma-ray beams using moderate energy electron beams colliding with large bandwidth X-ray beams (like those generated via bremsstrahlung), representing a compact, laser-less, more sustainable alternative to present ICS sources for nuclear photonics and photo-nuclear physics. SCS may have further interesting applications in cosmology (see Synchro-Compton catastrophe) and in plasma physics (plas
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Caroline Czelusniak - LABEC lab
16 giugno 2023
The term “cultural heritage” (CH) has been slowly changing to “social heritage” over the years. When we talk about cultural heritage studies we are not only talking about artworks such as paintings and sculptures but everything that concerns the study of our history, such as objects of anthropological interest. The diversity behind the characteristics of the materials to be studied (bones, organic pigments, metals) is so vast that different analytical techniques are applied in order to answer all the questions performed by historians, restorers, archaeologists, geologists, and all the other professionals involved in the CH field. In this framework, taking into account the historical value of the CH samples, accelerators based techniques are fundamental because they allow high performance, non-invasive and non-destructive analysis, or even when necessary, just a small amount of material is needed. Moreover, the accelerator based techniques offer a complete set of diagnostic analysis which cover the majority of the case studies found in CH. For this reason, a brief summary of the facilities and their techniques used for social heritage studies will be presented, starting from the big ones which perform neutron or muon radiography, passing through light sources and small accelerators. In addition, in the last years the demand for transportable instrumentation in the CH field has grown, which opened a new field of technological research: transportable accelerators. For this reason, the INFN (Florence division) in collaboration with CERN built MACHINA (Movable Accelerator for Cultural Heritage In-situ Non-destructive Analysis), the first transportable accelerator specifically for CH studies to be installed inside the Opificio delle Pietre Dure of Florence, a renowned restoration center.
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Adriano Pepato – AM per Acceleratori
19 maggio 2023
DIAM (Development and Innovation on Additive Manufacturing) is a workgroup of the INFN Padua division, focused on scientific and technological research in the field of Additive Manufacturing (AM) technologies. Three Laser Powder Bed Fusion (L-PBF) machines and equipment for post-production are available at DIAM, to allow the production and the analysis of additively manufactured materials such as copper, copper alloys, aluminium alloys, titanium alloys, Inconel 718, stainless steel, and refractory metals (Ta, Nb, W, Mo), which are particularly suitable for Nuclear Fusion and Particle Accelerator communities. DIAM participates in several international projects, implementing the AM in advanced fields such as nuclear fusion (e.g. DTT project) and particle accelerators (e.g. SPES project). The R&D programs include the development of AM powder alloys, the characterization of AM processes and produced materials, and finally, the implementation of Design for Additive Manufacturing (DfAM) technics in order to additively produce prototypes for components testing and validation. Several collaborations with public research organizations (such as PoliTo, PoliMi, University of Padua, CERN, ASI, ProM) and industries (EOS, TRUMPF, Pres-X, BAKER-HUGHES) make up the network on which DIAM chooses to implement the assigned INFN projects.
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Luca Piersanti – Design, test and commissioning of high gradient accelerating structures at LNF
14 aprile 2023
In the recent years there has been an increasing push towards the development of high gradient normal conducting accelerating structures for electron accelerators. In high brightness photo-injector facilities, for instance, the beam quality is directly related to the peak electric field on the cathode, so that the higher the field the better the beam parameters (e.g. emittance).
Moreover, the interest towards ultra-high gradient structures (>50 MV/m) as building blocks of future particle accelerators has been historically driven by CERN and SLAC, but in the last years other Laboratories showed an increasing enthusiasm for this topic. A design study for an X-band driven FEL source (Compact Light), and the Eupraxia@SPARC_LAB project to name a few.
The seminar will introduce the different kind of accelerating structures commonly used in electron linacs, defining main features, efficiency parameters, construction and design limitations. The introduction will be completed with a short state of the art of accelerating structures currently in operation in other international laboratories.
Then, a complete overview of the past, present and future prototyping activities on normal conducting accelerating structures at LNF will be presented. In particular, the R&D activity and high-power tests on three different structure categories will be covered:
(i) high gradient C-band travelling wave structures (designed for SPARC_LAB energy upgrade and ELI-NP project); (ii) high gradient clamped photo-guns working in S-band (SPARC_LAB, UCLA, ELI-NP) and C-band (I-FAST); (iii) ultra-high gradient X-band travelling wave structures (EuPRAXIA@SPARC_LAB prototype).
Finally, a discussion on the future applications and challenges will close the seminar.
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Grazia D'Agostino- InnovaTron: An innovative compact high-intensity proton cyclotron
10/02/2023
Radioisotopes for nuclear medicine can be produced either by nuclear reactors or accelerators. Commercial cyclotrons (E = 15-70 MeV) achieve currents up to or just above 1 mA. Both proton and H- cyclotrons are used. One of the decisive issues in the design and operation of cyclotrons is the choice of the beam extraction method. Typical methods are extraction by electrostatic deflector and by stripping.
The electrostatic deflector strongly limits the maximum beam intensity because of losses and induced heat-load on its septum. The latter method requires acceleration of H- beams which are sensitive for rest gas and Lorentz stripping and therefore require good vacuum and not too high magnetic field.
The self-extracting cyclotron is a promising tool for large-scale production of medical radioisotopes. The 14 MeV H+ machine uses an internal ion source and a magnetic field that features a sharp transition from the stable isochronous zone to the unstable fringe field, allowing spontaneous beam extraction. First harmonic coils increase the turn-separation at the entrance of the extraction path.
In 2000 a prototype build by the IBA company provided the proof-of-principle for self-extraction by the extraction of a proton current close to 2 mA. Recently, a simulation study has been done to improve the concept of self-extraction. Proton currents up to 5 mA are aimed for from the improved self-extracting cyclotron called InnovaTron.
A major variable of the beam simulations is the space charge effect in the cyclotron centre. An approach has been developed for a more accurate simulation of the beam extracted from the ion source and its acceleration in the first accelerating gaps under space charge conditions. The main features of the InnovaTron cyclotron are presented together with detailed results obtained for central region studies including space charge in beam dynamics simulations.
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Stefania Farinon and Dr.Marco Statera - Special Superconducting magnets for HiLumi LHC
13/01/2022
The luminosity upgrade of the Large Hadron Collider at CERN, which aims to increase the luminosity by a factor of more than five, includes as a relevant feature the replacement of many superconducting magnets, which are, to varying degrees, technically challenging and at the edge of technology. With 40 years of experience in the development of superconducting magnets, the Genoa and Milan Sections of INFN are involved in the development of some of these magnets that, while based on established NbTi technology, have required significant development activities by our laboratories. We are talking about the MBRD dipole, which separates and recombines the beams before and after the interaction points in CMS and ATLAS, and the higher-order correctors, a family of magnets that includes quadrupoles, sextupoles, octupoles, decapoles and dodecapoles. This seminar will explain all the activities carried out, from design to magnet series fabrication, to meet the performance required to be installed in the LHC.
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