The MUNES project (MUltidisciplinary NEutron Source) aims at the realization of an intense accelerator-based source of thermal neutrons, suitable for Boron Neutron Capture Therapy (BNCT). This ...exploits the interaction of 5 MeV protons onto a beryllium target, producing a fast neutron spectrum, which is moderated to the thermal range by a large assembly made of a Polytetrafluoroethylene (PTFE) tank filled with heavy water, surrounded by graphite blocks. The thermal neutron field is extracted through a bismuth beam port. The microdosimetric characterization of this field was performed using a cylindrical avalanche-confinement Tissue Equivalent Proportional Counter (TEPC) equipped with interchangeable cathode walls, positioned in front of the beam port. Measurements were taken both with a boron-doped wall and with an undoped one. The comparison of the two microdosimetric distributions allows to distinguish the relative dose contribution due to alpha particles and lithium ions from the BNC reaction from that of photons and other particles from neutron interactions on the cathode walls. The Relative Biological Effectiveness (RBE) was also calculated from the convolution of the measured spectra with a biological weighting function. This paper describes the experimental microdosimetric approach and the results of measurements with a boron-loaded cathode performed for the first time at an accelerator-based BNCT source.
•Microdosimetric spectra were taken at an accelerator-based neutron source for BNCT.•Measurements were performed both with boron-doped and undoped detector walls.•The dose fractions due to gamma, neutron and BNC processes were discriminated.•RBE and RBE-weighted dose were calculated using a biological weighting function.
Abstract
The Linear IFMIF Prototype Accelerator (LIPAc) is designed to accelerate 125mA of deuteron beam to 9MeV in continuous wave (CW). The superconductive RF Linac has not yet been installed and ...the final accelerating stage now under commissioning is the RFQ. This system has been designed and developed by INFN (Italy) before installation in QST (Japan). The RFQ is the longest in the World with its 9.8m and requires RF power injection from 8 independent and synchronized coupler ports. LIPAc demonstrated the acceleration of 125mA deuteron beam at 5MeV for 1ms with a 1s repetition period in 2019. A fundamental milestone to extend beam operations to CW is the completion of the RFQ cavity RF conditioning up to CW. This work presents the strategy followed to successfully reach CW RF injection at 80% of the nominal 132kV vane voltage. The field distribution correction scheme (acting on cooling system at various power levels) was successfully verified. We discuss as well the main challenges encountered on the way, which include updates of the RF system, failure of a circulator (by arcs) and the damages occurred on some of the RF couplers. Finally, the recent status and outlook will be provided.
Abstract
The LNL accelerator complex is equipped with two stable ion beams injectors, employing respectively negative and positive ion sources. In particular, a sputtering-type negative ion source ...and an Electron Cyclotron Resonance Ion Source (ECRIS) are installed on high voltage platforms, to provide the optimum injection energy in the downstream accelerators. Recently, the two injectors have been object of upgrades and developments, in order to improve the overall safety and reliability of the two systems, as well as the beams available for the users. This contribution describes the work related to the above-mentioned activities, the technical choices employed and the latest results on ion beams production.
Abstract
The Linear IFMIF Prototype Accelerator (LIPAc) is a high intensity D
+
linear accelerator; demonstrator of the International Fusion Material Irradiation Facility (IFMIF). In summer 2019 the ...IFMIF/EVEDA Radio Frequency Quadrupole (RFQ) accelerated its nominal 125 mA deuteron (D
+
) beam current up to 5 MeV, with 90% transmission for pulses of 1 ms at 1 Hz. This success was possible thanks to an intense previous campaign of modelization and measurements in order to characterize the RFQ input beam, which is affected by the ECR ion source extraction and the low energy beam transport. The simulation models used with the measurement benchmarks are here presented.
Worldwide efforts to tackle the nature of exotic nuclei comprise the construction of new-generation Radioactive Ion Beam facilities. The Italian community is deeply involved in the process and the ...construction of SPES at Legnaro National Laboratories (INFN) is progressing. This contribution describes the layout of SPES in all its flavours, from Nuclear Physics to Applications in Nuclear Medicine and Neutron Physics. In particular, the status of the SPES-β ISOL facility, together with some of the relevant physics cases and the associated equipment are described.
Abstract
The ADIGE (Acceleratore Di Ioni a Grande carica Esotici) injector consists of an electrostatic 1+ beam line, equipped with ion sources able to produce a wide variety of beams, coupled to a ...magnetic beam line, where charge multiplication is accomplished by implementing an Electron Cyclotron Resonance (ECR) based charge breeder. The injector is totally integrated in the SPES (Selective Production of Exotic Species) beam line, to allow the post-acceleration of radioactive ions and is now in an advanced phase of installation. The electrostatic 1+beam line has been put into operation and is now producing beams from alkali metals. This contribution concerns the first results of the beam commissioning of this part of the injector, with the description of the initial debug phase and the solutions adopted to ensure a reliable and continuous operation. Preliminary results of the 1+ beam line characterization will be shown, with a comparison between simulated and measured emittances.
LINUS is a project at the INFN Legnaro National Laboratories (LNL, Italy) to create a suite of different neutron sources (LSNS, NEPIR, SLOWNE) driven by existing accelerators. LSNS, driven by a 40 ...mA, 5 MeV proton RFQ, will use Li and Be targets to deliver cold, thermal, epithermal and fast neutrons. The SPES high current (0.75 mA), 70 MeV proton cyclotron will drive the NEPIR and SLOWNE facilities. NEPIR will alternatively deliver quasi mono-energetic neutrons with energy peak down to 20 MeV, and a neutron beam with a continuous energy distribution similar to that of neutrons present in the Earth atmosphere in the accessible energy range. SLOWNE is an intense neutron source for applications outside the LSNS range.
Progress in the design and construction of SPES at INFN-LNL Bisoffi, G.; Prete, G.; Andrighetto, A. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
06/2016, Letnik:
376
Journal Article
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INFN-LNL is constructing an ISOL (Isotope Separation On Line) facility delivering neutron rich ion beams at 10AMeV or beyond, making use of the linear accelerator ALPI as the secondary accelerator. ...The facility includes a direct ISOL target based on UCx and able to reach 1013fissions/s. In parallel, an applied physics facility will be developed, with applications in medicine and neutron production. The SPES project is a national facility, approved and funded. Commissioning with the first exotic species is expected in 2019. The primary accelerator is a commercial cyclotron, which will send a 40MeV, 200μA proton beam onto an UCx target, connected to SIS, PIS and LIS ion sources. The extracted beam is purified through a Low Resolution Mass Separator (LMRS, i.e. a Wien filter and a dispersive dipole), a beam cooler and a High Resolution Mass Separator (HRMS) and sent to an ECR charge breeder to boost the exotic beam charge state. The highly charged exotic beam is further separated in a MRMS (Medium Resolution Mass Separator) and injected into a 100% duty cycle RFQ and into the existing superconducting linac ALPI, which will be refurbished and upgraded to be an efficient exotic beam accelerator. The upgrade of ALPI will give ∼10AMeV energy to 132Sn19+, taken as the reference ion beam. The paper presents the status of the design and construction of the SPES facility.
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