ECPM 2006, Nice, France, 2-4 November DESIGN STUDIES OF THE 300AMEV SUPERCONDUCTING CYCLOTRON FOR HADRONTHERAPY Mario Maggiore Laboratori Nazionali del Sud Catania, Italy

ECPM 2006, Nice, France, 2-4 November OUTLINE INTRODUCTION MAGNETIC CIRCUIT PRELIMINARY EXTRACTION RESULTS INJECTION STUDY CAVITY DESIGN CONCLUSIONS

ECPM 2006, Nice, France, 2-4 November The 300 AMeV choice At the end of 2005 the SCENT project has been completed. The preliminary studies of a superconducting cyclotron able to accelerate ions with mass to charge ratio of 0,5 up to energy of 250A MeV were carried out by the Accelerator R&D group of LNS. In the March 2006, we have investigated the possibility to increase the extraction energy of the carbon ions up to 300 AMeV, keeping unchanged the main parameter of the machine. Moreover, we tried to extract the proton beam by the stripping process at the energy of 250 AMeV. Today…”The agreement between the Italian National Institute for Nuclear Physics and the Belgian firm Iba for the marketing, in biomedical field, of the first superconductive cyclotron producing protons and carbon ions as well, has been made official today. The innovative project, that will developed by the Infn Southern National Laboratories and realized with the contribution of the Iba specific twenty-year experience in the field of cyclotrons for medical applications, was conceived for the hospital centres of oncological hadrontherapy.” Medical News Today, 23 July 2006

ECPM 2006, Nice, France, 2-4 November Why 300AMeV is better than 250AMeV (carbon ions) ? Courtesy of HIMAC C 300 AMeV  174 mm depth C 250 AMeV  75 % of targets

ECPM 2006, Nice, France, 2-4 November Two machines not quite similar… 250 AMeV (p, 12 C 6+ ) 300 AMeV ( 12 C 6+ ) 250MeV (p) Pole Radius1325 mm B average (R ext )3.9 tesla  4.2 tesla Yoke diameter4900 mm  5100 mm Yoke height2900 mm Hill gap50 mm  30 mm Valley gap1050 mm  900 mm(variable) Max spiral angle73 deg  80 deg Weight340 tons  420 tons Current density41 amp/mm 2  45 amp/mm 2 Extraction Syst. 2 ED placed in the hills + stripping  2 ED placed in the valleys + stripping Number of cavities4 RF frequency(h=4)93 MHz  97 MHz

ECPM 2006, Nice, France, 2-4 November Magnetic circuit design A wider valley (45 deg) allows to get an higher energy gain per turn and to place a wide ED (43 deg) in order to keep relatively low the local electric field and make easy the extraction process. But… and Spiral angle versus radius flutter

ECPM 2006, Nice, France, 2-4 November Preliminary extraction results ED1 ED2 Radial env. Vertical env. MC Protons by 246 MeV Carbon by ED 300A MeV Beam envelopes C 300AMeV 246 MeV

ECPM 2006, Nice, France, 2-4 November Central region design E inj =25 AKeV V inflect = 14 KV gap inflect = 6 mm E inflect = 23KV/cm B o =3.22 tesla V dee = 70 KV E gap = 90 KV/cm SEE POSTER SESSION CENTRAL REGION DESIGN OF THE 300 AMeV SUPERCONDUCTING CYCLOTRON L. Calabretta, D. Battaglia, D. Campo, M. Maggiore, LAC Piazza, D. Rifuggiato

ECPM 2006, Nice, France, 2-4 November Cavity Design f o = MHz Q= 9200 max =100KV R sh = KΏ P loss =68 kW/cav N stem = 4 Height= 84 cm Length =230 cm Width = 43 deg

ECPM 2006, Nice, France, 2-4 November The fine tuning system Work in progress

ECPM 2006, Nice, France, 2-4 November Estimation of the forces acting on the trim rods 600 kg ! 20 cm =5 cm

ECPM 2006, Nice, France, 2-4 November Pole cap deformation due to the magnetic forces Applied load: 3000 tons Max displacement: 0.1 mm

ECPM 2006, Nice, France, 2-4 November Coils parameters Coil Parameters Size150x210 mm 2 Current density 45 amp/mm 2 Inner Radius1420 mm Distance from the M.P. 70 mm Energy Stored35 MJ Nominal Current (I) 900÷1000 amp Total current (NI)1.4 Mamp Max Magnetic field4.4 tesla Axial Force-9.09 MN Average Hoop Stress (peak) 156 (284) MPa

ECPM 2006, Nice, France, 2-4 November Conclusion The studies done so far show that the energy range of 300 AMeV for Carbon ions, can be achieved keeping the main structural parameters of the SCENT machine. We shown that it is possible to extract the proton beams by stripping at the energy of 250 MeV. Despite the high magnetic field and the low injection energy, we designed the central region working with four 70KV. More detailed design studies concerning the RF cavities, the dynamic’s beam, the fine tuning system and other, are in progress.

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ECPM 2006, Nice, France, 2-4 November