SPES (Selective Production of Exotic Species) is a facility under construction at INFN-LNL (Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro), aimed to produce intense neutron-rich radioactive ion beams

(RIBs). These will be obtained using the ISOL (Isotope Separation On-Line) method, bombarding a uranium carbide target with a proton beam of 40MeV energy and currents up to 200 μA. The target configuration was designed to obtain a

high number of fissions, up to 1013 per second, low power deposition and fast release of the produced isotopes. The exotic isotopes generated in the target are ionized, mass separated and re-accelerated by the ALPI superconducting LINAC at energies of 10AMeV and higher, for masses in the region of A = 130amu, with an expected rate on the secondary target up to 109 particles per second. In this work, recent results on the R&D activities regarding the SPES RIB production target-ion source system are reported

Andrighetto, Alberto

Ballan, M.

Boratto, E.

Borgna, Francesca

Corradetti, Stefano

De Ruvo, L.

Ferrari, M.

Guerzoni, M.

Manzolaro, Mattia

Margotti, A.

Meneghetti, G.

Monetti, Alberto

Mozzi, A.

Oboe, Roberto

Prete, G.

Rossignoli, Massimo

Sattin, N.

Scarpa, D.

Silingardi, R.

Vivian, Gianluca

Zenoni, Aldo

SPES (Selective Production of Exotic Species) is a facility under construction at INFN-LNL (Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro), aimed to produce intense neutron-rich radioactive ion beams (RIBs). These will be obtained using the ISOL (Isotope Separation On-Line) method, bombarding a uranium carbide target with a proton beam of 40 MeV energy and currents up to 200 μA. The target configuration was designed to obtain a high number of fissions, up to 10^13 per second, low power deposition and fast release of the produced isotopes. The exotic isotopes generated in the target are ionized, mass separated and re-accelerated by the ALPI superconducting LINAC at energies of 10AMeV and higher, for masses in the region of A = 130amu, with an expected rate on the secondary target up to 10^9 particles per second. In this work, recent results on the R&D activities regarding the SPES RIB production target-ion source system are reported

Andrighetto, A.

Corradetti, S.

Borgna, F.

Manzolaro, M.

Monetti, A.

Rossignoli, M.

Vivian, G.

Oboe, R.

Zenoni, A.

Archivio istituzionale della ricerca - Università di Brescia

The SPES High Power ISOL production target

ANDRIGHETTO, ALBERTO

CORRADETTI, STEFANO

BORGNA, FRANCESCA

MANZOLARO, MATTIA

VIVIAN, GIANLUCA

OBOE, ROBERTO

ZENONI, ALDO

MONETTI, ALBERTO

ROSSIGNOLI, MASSIMO

Archivio istituzionale della ricerca - Università di Padova

Scientific Open-access Literature Archive and Repository

DOI 10.1393/ncc/i2015-15194-xColloquia: UCANS-VIL NUOVO CIMENTO 38 C (2015) 194The SPES High Power ISOL production targetA. Andrighetto(1)(∗), S. Corradetti(1), M. Ballan(1)(2), F. Borgna(1)(3),M. Manzolaro(1), D. Scarpa(1), A. Monetti(1)(4), M. Rossignoli(1)(4),R. Silingardi(1), A. Mozzi(1), G. Vivian(1)(4), E. Boratto(1), L. De Ruvo(1),N. Sattin(1), G. Meneghetti(4), R. Oboe(5), M. Guerzoni(6), A. Margotti(6),M. Ferrari(7), A. Zenoni(7) and G. Prete(1)(1) INFN, Laboratori Nazionali di Legnaro - Legnaro (PD), Italy(2) Dipartimento di Fisica e Scienze della Terra, Universita` di Ferrara - Ferrara, Italy(3) Dipartimento di Scienze del Farmaco, Universita` di Padova - Padova, Italy(4) Dipartimento di Ingegneria Industriale, Universita` di Padova - Padova, Italy(5) Dipartimento di Tecnica e Gestione dei Sistemi Industriali, Universita` di PadovaVicenza, Italy(6) INFN, Sezione di Bologna - Bologna, Italy(7) Dipartimento di Ingegneria Meccanica e Industriale, Universita` di Brescia - Brescia, Italyreceived 22 February 2016Summary. — SPES (Selective Production of Exotic Species) is a facility underconstruction at INFN-LNL (Istituto Nazionale di Fisica Nucleare - LaboratoriNazionali di Legnaro), aimed to produce intense neutron-rich radioactive ion beams(RIBs). These will be obtained using the ISOL (Isotope Separation On-Line)method, bombarding a uranium carbide target with a proton beam of 40MeV en-ergy and currents up to 200μA. The target configuration was designed to obtain ahigh number of fissions, up to 1013 per second, low power deposition and fast releaseof the produced isotopes. The exotic isotopes generated in the target are ionized,mass separated and re-accelerated by the ALPI superconducting LINAC at energiesof 10AMeV and higher, for masses in the region of A = 130 amu, with an expectedrate on the secondary target up to 109 particles per second. In this work, recentresults on the R&D activities regarding the SPES RIB production target-ion sourcesystem are reported.PACS 29.25.Rm – Sources of radioactive nuclei.PACS 29.38.-c – Radioactive beams.1. – The SPES facilityIn the SPES [1] facility (layout shown in fig. 1), the radioactive ions will be producedwith the ISOL [2] technique by means of the proton-induced fission of uranium contained(∗) E-mail: alberto.andrighetto@lnl.infn.it (corresponding author)Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0) 12 A. ANDRIGHETTO et al.Fig. 1. – The SPES facility, with indication of its main systems.in the UCx (uranium dicarbide and residual graphite) [3] direct target and subsequentlyreaccelerated using the ALPI [4] accelerator complex. The Best C70 cyclotron will beused as a primary proton beam driver, with variable energy (30–70MeV) and a maxi-mum current of 0.8mA. In order to reach an in-target fission rate of 1013 fissions/s, aproton beam current of 200μA, 40MeV energy is necessary. The reaction products areextracted from the target by thermal processes (diffusion-effusion), ionized, mass sepa-rated and injected into the re-accelerator. In the SPES facility the first mass selectionwill be performed by a Wien Filter with a 1/100 mass resolution, installed just afterthe first electrostatic quadrupole triplet inside the production bunker. The transfer linetoward ALPI is equipped with several beam handling systems to purify the beam. In par-ticular, a Beam Cooler and a High Resolution Mass Separator (HRMS) with a 1/20000mass resolution will be developed and installed. Before the injection in the ALPI super-conducting LINAC, the charge state of the beam will be increased by means of a ECRCharge Breeder.2. – The target - Ion source unitIn an ISOL facility like SPES, the production target coupled with the ion sourcerepresents the core of the system. The SPES target is constituted by 7 UCx and 3graphite co-axial discs, with diameter and thickness of 40 and 1mm, respectively. Theprimary proton beam will be stopped in the target, dissipating its power and generatingby fission exotic nuclei in the 80 < A < 160 mass range. The exotic species will beFig. 2. – Elements produced at SPES with different ionization techniques.THE SPES HIGH POWER ISOL PRODUCTION TARGET 3Fig. 3. – Calculated target temperature distribution due to the proton beam power deposition.extracted from the target, ionized and accelerated to form the RIB. The main elementsproduced in the fission process are represented in fig. 2, together with an indication ofthe ionization mechanisms that will be used. Two different types of ion source will beadopted: the SPES surface ion source (SIS) and the SPES plasma ion source (PIS).In the first case, both the surface [5] and the laser [6] ionization mechanisms will beexploited (in the latter, the ion source is named laser ion source, LIS). In the PIS, thefission fragments are ionized according to the electron impact method [7].In order to gain knowledge of the thermal behavior of the target when impinged bythe primary proton beam, its temperature distribution was numerically simulated makinguse of the FEM (Finite Element Method) software ANSYS R©. The power distributionon the target was accurately calculated by means of the Monte Carlo based softwareFLUKA [1]. Figure 3 represents the target temperature results of the numerical model.It is possible to appreciate that the seven target discs temperature level is generallybetween 2000 and 2300 ◦C. The target and ion source unit is contained inside a watercooled, high vacuum aluminum chamber which is connected to the proton and RIB beamlines by means of quick connectors and gate valves.3. – The target materialThe properties required for the SPES target material are related to the efficiency ofthe release process, which can be divided into two different phases: a) the diffusion of theisotopes, generated inside the material, towards its grains surfaces (governed by Fickslaws), b) the effusion in high vacuum, either in the material pores or in the free spacessurrounding the target discs, towards the ion source. A large number of parameters canfavor the fast release of isotopes, both relative to the material properties and to thetarget operative conditions. The characteristics required for a material to work with ahigh efficiency as an ISOL target can be summarized as: a) high cross section for thefission reaction, b) ability to work at high temperatures (more than 2000 ◦C) in highvacuum without degradation of its thermo-mechanical properties, c) sufficient thermalemissivity and conductivity to dissipate the power generated by its interaction with theprimary beam without undergoing structural damage, d) high porosity and permeabilityto the created exotic species. In recent years [3], the synthesis, characterization and on-line test of uranium carbide thin discs (SPES target prototypes) have been successfullycarried out, and the production methodology can be considered ready to be used toproduce real UCx targets when SPES will be fully operative.4. – The target remote handlingThe target handling system consists of two independent apparatus, called verticaland horizontal devices that will move the target chamber to and from the on-line zone4 A. ANDRIGHETTO et al.(bunker). The vertical handling device will access the bunker through a hole on theroof and it will grab the target chamber using an interface tool placed on top of thechamber. On the other hand, the horizontal handling device will access the bunker usinga door. In this case, the interface tool is located on the rear of the chamber. Both deviceswill place and grab the chamber on a coupling table where a series of electro-pneumaticactuators will couple and uncouple the target chamber to the beam lines and open andclose the vacuum valves. The horizontal system is constituted of a PLC (ProgrammableLogical Controller) controlled Automatic Guide Vehicle (AGV) that will move the targetchamber to and from the bunker area and a Cartesian handling system, located on thetop of the AGV, that will move the target chamber to and from the coupling table oncethe vehicle is in position. The AGV will be guided automatically by means of an opticalsystem; moreover, manual operation of the AGV by an operator will be available.5. – ConclusionsSPES is the main nuclear physics project in Italy for the next years. It is an up todate project in the field of Nuclear Physics and in particular in the field of RIBs. TheSPES RIB complex will represent also an important step towards the development of thefuture European project EURISOL [8].∗ ∗ ∗The authors wish to thank Michele Lollo, Edoardo Visentin and Flavio Pasquato ofINFN-LNL for their precious technological support.REFERENCES[1] Monetti A., Andrighetto A., Petrovich C., Manzolaro M., Corradetti S.,Scarpa D., Rossetto F., Martinez Dominguez F., Vasquez J., Rossignoli M.,Calderolla M., Silingardi R., Mozzi A., Borgna F., Vivian G., Boratto E.,Ballan M., Prete G. and Meneghetti G., Eur. Phys. J. A, 51 (2015) 128.[2] Stora T., Nucl. Instrum. Methods B, 317 (2013) 402.[3] Corradetti S., Andrighetto A., Manzolaro M., Scarpa D., Vasquez J.,Rossignoli M., Monetti A., Calderolla M. and Prete G., Eur. Phys. J. WoC, 66(2014) 11009.[4] Bisoffi G., Bassato G., Battistella A., Bermudez J., Bortolato D., CanellaS., Chalykh B., Comunian M., Facco A., Fagotti E., Galat A., Giacchini M.,Gramegna F., Lamy T., Modanese P., Palmieri A., Pengo R., Pisent A., PoggiM., Porcellato A., Roncolato C. and Scarpa D., Eur. Phys. J. WoC, 66 (2014) 11003.[5] Manzolaro M., Andrighetto A., Meneghetti G., Rossignoli M., Corradetti S.,Biasetto L., Scarpa D., Monetti A., Carturan S. and Maggioni G., Nucl. Instrum.Methods B, 317 (2013) 446.[6] Scarpa D., Makhathini L., Tomaselli A., Grassi D., Corradetti S., ManzolaroM., Vasquez J., Calderolla M., Rossignoli M., Monetti A., Andrighetto A. andPrete G., Rev. Sci. Instrum., 85 (2014) 02B908.[7] Manzolaro M., Andrighetto A., Meneghetti G., Monetti A., Scarpa D.,Rossignoli M., Vasquez J., Corradetti S., Calderolla M. and Prete G., Rev.Sci. Instrum., 85 (2014) 02B918.[8] Blumenfeld Y., Butler P., Cornell J., Fortuna G. and Lindroos M., Int. J. Mod.Phys. E, 18 (2009) 1960.

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The SPES High Power ISOL production target

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