The SPES facility (Selective Production of Exotic Species), that is the INFN project for a Nuclear Physics facility with Radioactive Ion Beams (RIBs) is in advanced construction at the Legnaro National Laboratories. It will mostly provide neutron-rich exotic beams, through the production of ﬁssion fragments (1013 ﬁss/s) by an intense proton beam (200μA) on a direct UCx target. Several other targets will be developed, in order to provide users a large beam selection. Forefront research in nuclear structure and dynamics will be performed in the forthcoming years, studying a nuclear chart region far from stability. The expected beam intensities, their quality and their maximum available energies (up to 11MeV/n for A � 130) will provide the users with a modern and highly perfomant facility. Coordinated eﬀorts are being dedicated to the developments and upgrading of both the accelerator complex and of up-to-date experimental set-ups

Andrighetto, A.

Antonini, P.

Ballan, M.

Gramegna, F.

Prete, G.

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DOI 10.1393/ncc/i2018-18195-3Colloquia: IWM-EC 2018IL NUOVO CIMENTO 41 C (2018) 195The SPES exotic beam ISOL facility: Status of the project,technical challenges, instrumentation, scientific programF. Gramegna(1), G. Prete(1), A. Andrighetto(1), P. Antonini(1),M. Ballan(1), M. Bellato(2), L. Bellan(1), D. Benini(1), G. Bisoffi(1),J. Bermudez(1), G. Benzoni(3), D. Bortolato(1), F. Borgna(1),M. Calderolla(1), A. Calore(1), S. Canella(1), S. Carturan(1),N. Ciatara(1), M. Cinausero(1), P. Cocconi(1), A. Cogo(1), D. Conventi(1),V. Conte(1), M. Comunian(1), L. Costa(1), S. Corradetti(1), G. De Angelis(1),C. De Martinis(1)(4), P. De Ruvo(1), J. Esposito(1), E. Fagotti(1),D. Fabris(2), P. Favaron(1), E. Fioretto(1), A. Galatá(1), F. Gelain(1),M. Giacchini(1), D. Giora(1), A. Gottardo(1), M. Gulmini(1), M. Lollo(1),A. Lombardi(1), M. Manzolaro(1), M. Maggiore(1), D. Maniero(1),T. Marchi(1), P. F. Mastinu(1), A. Monetti(1), F. Pasquato(1),R. Pegoraro(1), A. Pisent(1), M. Poggi(1), S. Pavinato(1), L. Pranovi(1),D. Pedretti(1), C. Roncolato(1), M. Rossignoli(1), L. Sarchiapone(1),D. Scarpa(1), J. J. Valiente Dobon(1), V. Volpe(1), A. Vescovo(1)and D. Zafiropoulos(1)(∗)(1) INFN, Laboratori Nazionali di Legnaro - Legnaro (PD), Italy(2) INFN, Sezione di Padova - Padova, Italy(3) INFN, Sezione di Milano - Milano, Italy(4) Dipartimento di Fisica, Università di Milano - Milano, Italyreceived 3 December 2018Summary. — The SPES facility (Selective Production of Exotic Species), thatis the INFN project for a Nuclear Physics facility with Radioactive Ion Beams(RIBs) is in advanced construction at the Legnaro National Laboratories. It willmostly provide neutron-rich exotic beams, through the production of fission frag-ments (1013 fiss/s) by an intense proton beam (200 μA) on a direct UCx target.Several other targets will be developed, in order to provide users a large beam se-lection. Forefront research in nuclear structure and dynamics will be performed inthe forthcoming years, studying a nuclear chart region far from stability. The ex-pected beam intensities, their quality and their maximum available energies (up to11 MeV/n for A  130) will provide the users with a modern and highly perfomantfacility. Coordinated efforts are being dedicated to the developments and upgradingof both the accelerator complex and of up-to-date experimental set-ups.(∗) On behalf of the SPES Collaboration.Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0) 12 F. GRAMEGNA et al.1. – IntroductionAdvanced scientific infrastructures are needed to progress in many fields of science,and they are overall important in nuclear and sub-nuclear physics. In particular, theconstruction of still more powerful radioactive beam facilities allows to deeply advancein understanding nuclear structure. Moreover, using post-accelerated radioactive beamseven nuclear reaction studies can be performed, which enlarge the knowledge of nuclearmatter far from stability. One of such new facility is SPES, the INFN RIB infras-tructure, which is under construction at the Legnaro National Laboratory in Italy [1].The layout of the facility is shown in fig. 1. The project was born few years ago withthe intent to construct a multipurpose facility. Four different phases were in fact de-fined: α-phase - construction of the main building and installation and commissionigof a proton driver based on a high intensity (up to 750μA) 70 MeV commercial cy-clotron; β-phase - construction of a RIB facility with a low energy area (non reaccel-erated beams) and a post-acceleration beam facility, by upgrading the ALPI Linac ofLNL; γ-phase - related to the development of two areas: on one side the RILAB ac-tivity, to which a bunker is dedicated, where research on new radio-isotopes productionwill be performed and where the activity will be dedicated to cross section measure-ments, high power new target tests, radioisotope production tests and connected testsof radio-pharmaceuticals; on the other end, a production facility in collaboration witha private company is going to be defined and to be operated in the RIFAC bunkerand related pharmaceutical laboratories; this part is under discussion for a cooperationbetween INFN and a private company in order to produce radio-isotopes for medicaldiagnosis and therapy; δ-phase - neutron beam production by interaction of protonswith heavy and light targets for either continuum spectra production (SEE: Single EventFig. 1. – Upper part: view of the new SPES building (on the right) and of the TANDEM-ALPIcomplex (on the left). Lower part: layout of the SPES facility.THE SPES EXOTIC BEAM ISOL FACILITY ETC. 3Effect study) or quasi mono-energetic spectra: applications of the neutron source rangefrom nuclear astrophysics to test of electronics in space and characterization of nuclearwaste.2. – The SPES β-projectThe main part of the project is related to the production of a Radioactive Ion Beam(RIB) facility and, in particular, an ISOL facility devoted to the production of neutron-rich element by means of fission induced by protons on uranium: an intense protonbeam (200 μA) is directly sent onto a sliced UCx target, with the final aim to produceup to 1013 fiss/s [2]. The proton driver is a B70 cyclotron, produced by the BESTcompany [3] and can deliver two beams simultaneously, at the moment with the sameenergy but with the possibility of modulating different intensities at the two ports. TheB70 cyclotron have been installed and commissioned and it is ready to operate as is shownin fig. 2. A training period for the personnel has been performed and will continue inthe forthcoming period. The machine has demonstrated to be stable and reliable and aproton beam of 70 MeV with a current up to 500μA has been sent onto a high powerbeam dump (35 kW).The core of the project is the Target-Ion Source (TIS) system [4], which is designedto substain up to 8 kW of power on the target. The TIS is integrated in the FrontEnd, a peculiar part of the SPES accelerator which is installed inside the productionbunker. The offline FE actually under test is shown in fig. 3. It couples the cyclotronto the TIS itself proton entrance channel and, downstream, it consists of a first selectionFig. 2. – Views from the SPES building area where the B70 BEST cyclotron is installed. In thelower picture the beam line towards the RIB production is in the foreground.4 F. GRAMEGNA et al.Fig. 3. – Picture of the offline Front End of SPES.stadium of the produced Radiactive Beams (Wien Filter). The proton beam impingesat 90◦ degree with respect to the extracted RIB, interacts in the UCx target and finallystops in the last part of the target set-up (Beam Dump), which consists of a series ofgraphite disks. In order to satisfy different needs, three kind of TIS have been developed:a Surface Ion Source (good efficiency and selectivity for elements like Rb, cs, Ba); aPlasma Ion Source (necessary to ionize elements with high ionization potential, but withvery poor selectivity); a Laser Ion Source (which is based on the laser resonant photo-ionization and it is very powerful and highly selective) [5]. The produced RIBs after theirextraction by the TIS are directed towards the Wien Filter, which can provide a selectionof ΔM/M  1/150. The major part of the produced radioactivity is kept, so far, insidethe bunker itself. Then, outside the bunker, a first series of elements (a Magnetic Dipoleplus a series of electrostatic elements) will complete the selection reaching a resolutionof ΔM/M  1/200. All this is called Low-Resolution Mass Separator system (LRMS).Two safety systems (SS) are provided for maintenance operation, able to unlock thetarget ion-source system from the Front End and to replace it remotely. The main SSis a horizontal Automated Guided Vehicle (AGV) based system, which moves into thebunker, dismount the target and takes it to the temporary storage. A second handlingis provided vertically, in case the horizontal system is mulfunctioning: in the roof of thebunker a series of concrete blocks can be removed and a crane-like system can operateand remove the target. A strong study on radiation hard material has been performedin collaboration with the Pavia University and INFN section, since the Front End mustoperate under a high radiation field inside the bunker: an upgraded version of the FE hasbeen designed, in which many parts have been replaced in order to fullfill the requirementsof radiation hardness of materials and sealing.The layout of the transport line from the production bunker to the low-Energy area(non-reaccelerated RIBs) is shown in fig. 4: after the Wien Filter, which is still installedin the production bunker the beam is selected and sent to a 90◦ Magnetic Dipole andthen transported through a series of electrostatic elements (Triplets, Dipoles) until aDiagnostic Tape Station, designed to characterize the produced beams at the exit of theLRMS. Furthermore, the RIBs may also be transported towards a Beam Cooler necessaryto couple the emittance of the beam to the High-Resolution Mass Spectrometer (HRMS),THE SPES EXOTIC BEAM ISOL FACILITY ETC. 5Fig. 4. – Layout of the SPES production area, from the Cyclotron area towards the productionbunker, where the Front End is installed and, finally the transport line toward the low-energy1+ area for non-reaccelerated beam physics. In the upper left part of the layot the HRMS areais also shown.which is under design, in order to reach a separation up to ΔM/M = 1/20000.At the exit of the HRMS the transport line can be splitted: on one side the highlyresolved RIB can be sent back to the Low Energy Area, on the other side it can be senttowards the post-accelerator. A Charge Breeding Stage (CB), necessary to charge up theisotopic species from 1+ to n+, is foreseen before the injection in the post accelerator.After the CB a further Medium Resolution Mass Spectrometer (MRMS) is used to cleanup from possible contaminants generated in the Charge Breeder plasma chamber. In fig. 5a picture of the Charge Breeder, which is under installation at LNL is shown togetherwith some optical elements of the 1+ transport line, called ADIGE.The installation of optical elements, power supplies and of the High Voltage platformof the MRMS has been performed together with the realization of electrical and watercooling plants. In order to couple the 1+ transport line and therefore to properly injectthe RIBS into the ALPI post accelerator, a new normal conductive Resonant FrequencyQuadrupole (RFQ), entirely designed at LNL is being constructed: the RFQ injection en-ergy is 5.7 keV/n and the exit energy 727 keV/n. The 24 RFQs electrodes were deliveredand the construction of the tanks is progressing.The ALPI post-accelerator is undergoing a major upgrading: transmission proper-ties, beam intensities and energies will be improved. The main objectives of the ALPIupgrade are: a) the increase the reliability of the accelerator; b) limit the heavy ionbeams (A/Q = 6–7) losses (maintainability increases with a low contaminated machine);c) increase the energy and the beam current for RIB experiments. The strategy cov-ers also an improved beam instrumentation which should permit the implementation ofsemi-automatic procedures to allow a better tuning and better reproducibility.6 F. GRAMEGNA et al.Fig. 5. – The ADIGE Installation phase. Top left: transport line towards the MMRS. Top right:Cabling the Charge Breeder. Bottom: n+ transport line towards the RFQ.Fig. 6. – Picture of the Tape Station systems in costruction at LNL: two for beam diagnosticsand characterization and one for β-decay study. On the right picture a particular of the capstainfor the tape rolling.THE SPES EXOTIC BEAM ISOL FACILITY ETC. 7The SPES performances in terms of beam intensities at the production/extractionpoint (after the 1+ ionization) and, for post accelerated RIBs, at the secondary targetposition (experiment) have been evaluated with MCNPX and reported on the LNL web-site [6]. Users can download the Beam Tables together with the description of the systemfrom the web page. Moreover, specific tests on the TIS system have been performed andhave demonstrated the capability of the sliced SPES target to produce extra yields withrespect to the bulk configuration, which was originally used at HRIBF at Oak RidgeNational Laboratory (USA) [7].The SPES scientific program has been discussed in several international meet-ings, where a Scientific Advisory Committe has analyzed the several Letters of Intentwhich were presented. Up to date instrumental set-ups (PRISMA [8], GARFIELD [9],GALILEO [10] etc.) together with specific ancillary detectors are present at LNL andhave been updated to be used with RIBS. Some other apparatus, developed within Eu-ropean Collaborations, will be travelling (like AGATA [11], FAZIA [12] and NEDA [13])and will come to LNL for specific experimental campaigns. Some more instruments areunder development on purpose for the experimental activity at SPES, like for examplean Active Target for SPES (ATS) and a β-decay station as shown in fig. 6. In fact, asis shown in the picture two tape stations will be constructed for beam diagnostics andcharacterization, while a third one for β-decay studies.REFERENCES[1] https://web.infn.it/spes.[2] Gramegna F. et al., Acta Phys. Pol. B, 46 (2015) 591; 69 (999) 1666.[3] http://www.bestcyclotron.com/products.html.[4] Andrighetto A. et al., Eur. Phys. J. A, 25 (2005) 41.[5] Scarpa D. et al., Eur. Phys. J. A, 47 (2011) 32.[6] https://web.infn.it/spes/index.php/news/spes-beam-tables.[7] http://accelconf.web.cern.ch/AccelConf/a98/APAC98/5C003.PDF.[8] Stefanini A. M. et al., Nucl. Instrum. Methods A, 701 (2002) 217c.[9] Bruno M., Gramegna F. et al., Eur. Phys. J. A, 49 (2013) 128.[10] Ur C. A., J. Phys. Conf. Ser., 366 (2012) 012044.[11] Akkoyun S. et al., Nucl. Instrum. Methods A, 668 (2012) 2658; Gadea A. et al., Nucl.Instrum. Methods A, 654 (2011) 88.[12] Bougault R. et al., Eur. Phys. J. A, 50 (2014) 47.[13] Jaworski G. et al., Nucl. Instrum. Methods A, 673 (2014) 64.

The SPES exotic beam ISOL facility: Status of the project, technical challenges, instrumentation, scientiﬁc program

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The SPES exotic beam ISOL facility: Status of the project, technical challenges, instrumentation, scientiﬁc program

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