This paper provides an overview of the worldwide first commissioning of a gantry beamline with a rotator at the MedAustron synchrotron-based proton/ion cancer therapy facility in Wiener Neustadt, Austria. The gantry beamline consists of the high energy beam transfer (HEBT) line and the gantry beam transport system. It transports the beam from the synchrotron to the gantry-room isocenter. The HEBT transports the beam from the synchrotron to the gantry entrance, which is the coupling point between the HEBT and the gantry. The rotator is one of the HEBT modules, thus it is an integral part of the gantry beamline. The MedAustron rotator is the worldwide first rotator system used to match slowly extracted asymmetric beams from the synchrotron to the rotating gantry. In this paper, main attention is paid to ion-optical and beam-alignment aspects of the beamline commissioning. A novel orbit-correction and beam-alignment technique has been developed specifically for the beamline with the rotator. While the theoretical concept of the rotator has existed for almost two decades, the MedAustron rotator is the first hardware implementation of this concept all over the world. The presented overview of the beamline commissioning includes a description of the principal technical solutions and main results of the first beam-transport measurements. Since the measured beam size and beam position agree well with theoretical predictions, one can conclude that the proof-of-concept of the rotator-matching has been successfully accomplished.

Rotating gantries are commonly used in ion-therapy facilities to assist and support optimizing the dose distribution delivered to the patient. They are installed at the end of the beamlines and rotated mechanically in the treatment room. In synchrotron-based facilities, the gantries must be able to transport slowly extracted beams with essentially different emittance patterns in the two transverse planes. Such beams will be referred to as the asymmetric beams. A special device called rotator has been proposed as a possible solution. The worldwide first beamline with the rotator has been recently commissioned. The original rotator concept uses an "external" rotator that is a part (a module) of the beamline the gantry is connected to. In this paper, a novel gantry ion-optical concept integrating the rotator optics into the gantry optics is introduced. The first-order gantry transfer matrix satisfies the so-called sigma-matching ionoptical constraints, and-at the same time-it possesses the format of a rotator transfer matrix. The rotator-matching and the sigma-matching principles are combined in the gantry transfer matrix, which means that the sigma-matching gantry acts simultaneously as a rotator without the need for an extra rotator device. In addition, scattering in the gantry nozzle is used to balance the asymmetric beam emittances in the two transverse planes without an additional scattering foil. In this way, the presented ion-optical concept combines all three known matching techniques-the sigma matching, the rotator matching, and the scattering-foil matching-within the gantry beam transport system. Such a beam transport system provides the best matching result and full angular independence of the beam parameters at the gantry isocenter. It also makes it possible to optimize the beam parameters not only at the gantry isocenter but also at the beam monitors located in the gantry nozzle without increasing the number of gantry quadrupoles. There are two possible versions of such gantry optics: the point-to-point and the parallel-topoint optics. They both are presented in this paper. Theoretical calculations are supported by beam transport simulations performed with the WinAGILE code. Feasibility of the newly proposed ion-optical concept is demonstrated on the MedAustron proton gantry. However, it can be applied to any rotating gantry at any ion-therapy facility. The presented design is the first rotatorlike gantry ion-optical concept worldwide.

MedAustron is a synchrotron-based hadron therapy center located in Lower Austria. Accelerated proton beams with energies of 62-252 MeV/u are used to treat patients since 2016. The carbon ion beam is currently under commissioning and will provide treatment in 2019 with energies of 120-400MeV/u. Two of the four irradiation rooms are used for clinical treatment while the preparation of the Gantry beam line is ongoing. Proton beams of up to 800 MeV will be provided for non-clinical research. The Injector features three identical ECRIS from Pantechnik, two of which are used to generate the proton and the carbon beam respectively. The medical environment of the accelerator puts strict requirements on the ion source long-term stability operation. The extracted beam current from the source allow for maximum current fluctuations on the order of ±2.5% on continuous run. In this work we discuss the impact of the ion source performances on the characteristics and stability of the entire accelerator. Further, we discuss the latest progress on carbon commissioning and the future perspectives with particular emphasis on the source requirements. INTRODUCTION The MedAustron is a synchrotron-based therapy center for cancer treatment. The design of the accelerator is based on PIMMS and CNAO [1,2]. Currently 26 patients (fractions) per day are treated with proton ion beams since 2016. Medical treatment with carbon ions is planned to start in 2019 [3]. A proton beam up to 800 MeV/u will be provided for non-clinical research. The Injector shown in Fig. 1 features three identical Supernanogan ECRIS from Pantechnik. One is reserved for proton beams production and one for carbon beams production. The third is foreseen as future use for clinical and non-clinical research. The extracted beam from the source at 8 keV/u is transported through the LEBT line to the linear accelerator. The LINAC contains a Radio Frequency Quadrupole (RFQ) module which accelerates the beam to 400 keV/u followed by a Buncher and an IH-Tank cavity where the energy reaches 7 MeV/u and finally by a Debuncher cavity. Through the Mid Energy Beam. Transport (MEBT) line the beam is then injected in the synchrotron where it reaches the clinical e non-clinical energies mentioned before. A slow extraction 3rd order resonance method via Betratron Core is used to extract the particles from the synchrotron. Through the High Energy Beam Line (HEBT) the beam is sent to four available irradiation rooms: IR1 with horizontal beamline for non-clinical research, IR2 with a horizontal and a vertical beamline, IR3 with a horizontal beamline and IR4 with a proton Gantry. The weekly machine uptime during clinical operation between 90% and 97% [4]. THE IONS SOURCE The identical design and the availability of three independent source lines allows for parallel running of the sources and for source switching in case of emergency. The ion beam in the source is produced through the Electron Cyclotron Resonance (ECR) heating mechanism [5]. The neutral gas is brought into a state of plasma magnetically confined in the vacuum vessel and the ions are extracted from the chamber with a dedicated extraction system. The Supernanogan of Pantechnik has been described in detail in [6]. It operates at 14.5 GHz heating frequency and is it entirely equipped with permanent magnets both for the radial magnetic field than for the longitudinal magnetic field with a BECR of 0.5 T. An axial mirror ratio Bmax/Bmin about two times higher than the ECR resonance magnetic field is obtained [5]. The plasma has limited contact to the chamber walls and the high charge state ions concentrate in the center of the extracted beam with a triangular intensity distribution. The longitudinal beam profile depends mainly on extraction parameters with respect to the plasma potential. The source body is placed at 24 kV, while a puller electrode is placed at negative potentials of about 2 kV to accelerate the beam towards the focus. The focus electrode on the order of 1.5 kV is fine tuned to adapt the beam size to the focal point of the dipole magnet for a good transmission into the beam line and further matching into the RFQ. The DC Bias tip, introduced from the backside of the vacuum chamber into the plasma, reduces the ion losses towards the injection. The RF tuner position is used to reduce the reflected power. The typical source parameters used for the proton and the carbon source are indicated in table 1: ___________________________________________ † nadia.gambino@medaustron.at 23th Int. Workshop on ECR Ion Sources ECRIS2018, Catania, Italy JACoW Publishing ISBN: 978-3-95450-196-0 doi:10.18429/JACoW-ECRIS2018-MOB2 Applications MOB2 5 Co nt en tf ro m th is w or k m ay be us ed un de rt he te rm so ft he CC BY 3. 0 lic en ce (© 20 18 ). A ny di str ib ut io n of th is w or k m us tm ai nt ai n at tri bu tio n to th e au th or (s ), tit le of th e w or k, pu bl ish er ,a nd D O I.

MedAustron is a synchrotron-based hadron therapy center located in Lower Austria. Accelerated proton beams with energies of 62–252 MeV/u are used to treat patients since 2016. The carbon ion beam is currently under commissioning and will provide treatment in 2019 with energies of 120–400MeV/u. Two of the four irradiation rooms are used for clinical treatment while the preparation of the Gantry beam line is ongoing. Proton beams of up to 800 MeV will be provided for non-clinical research. The Injector features three identical ECRIS from Pantechnik, two of which are used to generate the proton and the carbon beam respectively. The medical environment of the accelerator puts strict requirements on the ion source long-term stability operation. The extracted beam current from the source allow for maximum current fluctuations on the order of ±2.5% on continuous run. In this work we discuss the impact of the ion source performances on the characteristics and stability of the entire accelerator. Further, we discuss the latest progress on carbon commissioning and the future perspectives with particular emphasis on the source requirements.

MedAustron is a synchrotron-based Particle Therapy Accelerator located in Wiener Neustadt, Austria, which is delivering beams for medical treatment since end of 2016. The accelerator provides clinical proton beams in the energy range 62-252 MeV and is designed to provide carbon ions in the range 120-400 MeV/n to three ion therapy irradiation rooms IRs, including a room with a proton Gantry. Proton beams of up to 800 MeV will be provided to a fourth room dedicated to research. Presently, proton beams are delivered to the fixed horizontal beam lines of three rooms. Beam commissioning of the vertical beam line of the second IR is being completed and the beam line is in preparation for clinical treatment. Commissioning of the accelerator with carbon ions is advancing and first clinical beams have been sent to the IRs, while the preparation for the Gantry beam line is ongoing. A slow extraction 3rd order resonance method is used to extract particles from the synchrotron between 0.1-10 seconds to favor control of the delivered dose during clinical treatments. The main characteristics of the accelerator and results obtained during the latest commissioning activities are presented.

The MedAustron therapy accelerator[1,2] is intended to treat cancer patients with proton and carbon beams of 62252 MeV and 120-400MeV/u respectively. The accelerator features three Supernanogan ECR ion sources, a 400keV/u RFQ and a 7MeV/u interdigital H-mode Linac. A middle energy beam transfer line also serves as injector into a 77m synchrotron from which the beam may be transferred to 4 different irradiation rooms, 3 of which are dedicated to medical treatment. The therapy accelerator is in clinical operation since end 2016 [2] and is currently solely configured for the use of protons. After activation of a new vertical beam line the next clinical objective is to enable treatments using C6+ ions which triggered the carbon commissioning of the accelerator in 2017. This paper will discuss the ongoing carbon commissioning in the different sections of the accelerator, achieved efficiencies and outlook on future carbon activities. CARBON COMMISSIONING As the beam commissioning is tackled while parts of the machine are already in clinical use for proton therapy, the respective beam time is rather limited. Yet there is an important advantage to this situation which is that one profits from comfortable preparation and anylsis times in between dedicated beam commissioning shifts. Therefore a commissioning strategy was chosen as to preliminary test different parts of the machine as early as possible under different situations to identify and mitigate complications already at an early stage. The presented commissioning performance is preliminary results from the first tests of the MedAustron accelerator complex with carbons. Ion Source Three identical Supernanogan electron cyclotron resonance ion sources (ECRIS) are installed at MedAustron. Source 1 is driven with hydrogen gas for “proton” production (H+) whereas Source 2 is tuned for carbon ( C4+) and uses a CO2 and He gas mixture. Source 3 serves as a spare source and will be commissioned with multiple ion types for non-clinical research and to allow a swift substitution if need be. The commissioning of the second ion source for medical treatment with carbon beam is almost finalized. Stable source settings have been found which allow to reach the nominal carbon current for medical treatment (on the order of 150 μA). Long term stability tests of the extracted beam current showed only single deviations of the nominal current <5% within 45hours periods. The installation of an overpressure valve between gas bottle pressure reducer and injection mass flow controller mitigates a pressure build up in the CO2 line and improved plasma stability considerably. Commissioned source settings for optimal performance are summarized in Table 1. A more detailed description of the source commissioning can be found in [2]. Linac & MEBT As the ion sources deliver the same charge to mass ratio independent of the used particle type (H+ or C4+) the Linac is optimized for exactly this situation. Thus the electromagnetic field strengths and phase delays barely need adjusting in respect to proton operation as foreseen by design. The main commissioning effort concerning the Table 1: Detailed source settings of the Supernanogan ECRIS for carbon usage. RF Freq. [GHz] 14.464

MedAustron is a synchrotron based medical accelerator facility for particle therapy providing protons and carbon ions with clinical energies from 60 MeV to 250 MeV and 120 MeV/n to 400 MeV/n respectively. The facility features four irradiation rooms, three of which are dedicated to clinical operation and a fourth one to non-clinical research. Commissioning of all fixed lines has been completed for protons, while the commissioning for carbon ions and a proton gantry is ongoing. For the commissioning of carbon ions, precise measurements of the transverse beam emittance in the synchrotron are of importance, to minimize beam losses and to correct for possible emittance variations due to the different clinically relevant beam intensities defined by a degrader at the end of the Linac. The transverse beam emittance in the MedAustron synchrotron is measured via scraping at non-dispersive regions of the ring. The analysis procedure as well as emittance reconstruction accuracy for simulated data will be described in this paper, together with measurement results from the carbon commissioning.

This paper presents a systematic study of the halo collimation of ion beams from proton up to uranium in synchrotrons. The projected Facility for Antiproton and Ion Research synchrotron SIS100 is used as a reference case. The concepts are separated into fully stripped (e.g., U-238(92+)) and partially stripped (e.g., U-238(28+)) ion collimation. An application of the two-stage betatron collimation system, well established for proton accelerators, is intended also for fully stripped ions. The two-stage system consists of a primary collimator (a scattering foil) and secondary collimators (bulky absorbers). Interaction of the particles with the primary collimator (scattering, momentum losses, and nuclear interactions) was simulated by using FLUKA. Particle-tracking simulations were performed by using MAD-X. Finally, the dependence of the collimation efficiency on the primary ion species was determined. The influence of the collimation system adjustment, lattice imperfections, and beam parameters was estimated. The concept for the collimation of partially stripped ions employs a thin stripping foil in order to change their charge state. These ions are subsequently deflected towards a dump location using a beam optical element. The charge state distribution after the stripping foil was obtained from GLOBAL. The ions were tracked by using MAD-X.

Activation data for an aluminum target irradiated by 200MeV/u 238U ion beam are presented in the paper. The target was irradiated in the stacked-foil geometry and analyzed using gamma-ray spectroscopy. The purpose of the experiment was to study the role of primary particles, projectile fragments, and target fragments in the activation process using the depth profiling of residual activity. The study brought information on which particles contribute dominantly to the target activation. The experimental data were compared with the Monte Carlo simulations by the FLUKA 2011.2c.0 code. This study is a part of a research program devoted to activation of accelerator construction materials by high-energy (⩾200MeV/u) heavy ions at GSI Darmstadt. The experimental data are needed to validate the computer codes used for simulation of interaction of swift heavy ions with matter.

The FAIR synchrotron SIS100 will be operated with high-intensity proton and ion beams [1]. The collimation system should prevent beam loss induced degradation of the vacuum, activation of the accelerator structure and magnet quenches. A conventional two-stage betatron collimation system is considered for the operation with protons and fully-stripped ions [2]. We propose to use 1 mm thick tungsten foil as the first stage – primary collimator (scatterer) and two 400 mm blocks at as the second stage – secondary collimators (absorbers).

The FAIR synchrotron SIS 100 will be operated with high-intensity proton and heavy-ion beams. The collimation system should prevent beam loss induced degradation of the vacuum, activation of the accelerator structure and magnet quenches. A conventional two-stage betatron collimation system is considered for the operation with protons and fully-stripped ions. Particle tracking and ion-collimator interaction simulations of the collimation system were performed. The angular and momentum distributions of the scattered halo particles were described using analytical models and numerical tools like ATIMA and FLUKA. MADX was used for the multi-pass tracking simulations. The results obtained for the collimation cleaning eciency as a function of the ion species and beam energy together with the detailed beam losses distributions along the ring circumference are presented. This work highlights the main aspects of the collimation of fully-stripped ion beams in the intermediate energy range using conventional two-stage systems.

EuCARD is a joined accelerator R&D initiative funded by the EU. Within this program, GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt is performing R&D on materials for accelerators and collimators in workpackage 8 (ColMat). GSI covers prototyping and testing of a cryogenic ion catcher for FAIR’s main synchrotron SIS100, simulations and studies on activation of accelerator components e.g. halo collimatiors as well as irradiation experiments on materials foreseen to be used in FAIR accelerators and the LHC upgrade program. Carbon-carbon composites, silicon carbide and copper-diamond composite samples have been irradiated with heavy ions at various GSI beamlines and their radiation induced property changes were characterized. Numerical simulations on the possible damage by LHC and SPS beams to different targets have been performed. Simulations and modelling of activation and long term radiation induced damage to accelerator components have started. A prototype ion catcher has been built and first experiments have been performed in 2011. New collaborations with other institutes and industry participating in the EuCARD framework have been established and findings of the joined R&D effort influence decisions in the FAIR project and LHC upgrade. This work offers an overview and points out highlights of the GSI’s ColMat activities which are not separately presented within other contributions to this proceedings. ION INDUCED DAMAGE IN MATERIALS FOR LHC COLLIMATORS JAW To study radiation-induced dimensional changes and degradation of thermo-mechanical properties, graphite and AC 150 carbon-carbon composite samples were irradiated with heavy and light ions. The irradiation experiments were performed at energies of 11.1 MeV/u, with GSI the UNILAC accelerator at GSI. Similar studies have been started on new candidate materials such as diamond-metal composites. Depending on the specific modifications and functional properties, the most suitable material will be selected for the construction of collimators to be used for FAIR and the LHC upgrade. ∗Work supported by the EU program EuCARD, WP 8, ColMat † j.stadlmann@gsi.de Figure 1: Profilometer scan across the pristine-irradiated border of a AC150 carbon-carbon composite sample, exposed to 1·10 U ions/cm, 11.1 MeV/u, showing outof-plane contraction of irradiated part. Carbon fiber-carbon composite (CFC) Dimensional changes of AC 150 grade carbon fibercarbon composite (CFC) exposed to swift heavy ions were studied by profilometry. A diamond tip is scanned across the interface between irradiated and masked non-irradiated interface. Profilometry of CFC irradiated samples are performed on samples cut along two perpendicular orientations of the fibers. Ion-irradiated CFCs are shrinking along the ion beam direction. This behavior shows that the dimensional change contribution is dominated by the fibers. The graphitic matrix swells on the ion beam direction due to the evolution of the irradiated material towards glassy carbon, which has a lower density (≈ 1.5 g/cm [1]). This effect is specific for ion irradiation, and scales with the linear energy-loss. The fibers are swelling along the radius and are contracting along the axis. Fibers are consisting of coaxial disposed planes, in case of PAN (Polyacrylonitrile) derived fibers. For pitch derived fibers the arrangement of graphitic planes is more complex, but the axis of the planes is always perpendicular to the axis of the fibers. PAN derived fibers are more sensitive to radiation induced damage than pitch derived ones. The radiation-induced shrinking of our CFC material is dominated by fiber axial shrinking (graphitic in-plane contraction that tends to heal vacancies produced by irradiation). The swelling of the fibers is accommodated by the porosity within the graphitic matrix and at the fiber matrix interfaces. The behavior differs along the two cutting directions of the CFC material due to different types of fibers and weaving for this two directions. The strongest contraction effect takes place along the well oriented fibers seen on the “in plan”-cut micrograph, reaching ≈ 4-5 μm (see Fig. 1). — pristine — 1x10 i/cm 12 2

Residual activity is one of the main beam-loss limiting factor in high-energy proton accelerators. In order to ensure 'hands-on' maintenance 4 h after the shutdown, the losses of proton beam should be kept below 1 W/m. It has been shown in our previous publications that the beamloss criteria for heavy-ion machines may be established by rescaling the '1 W/m criterion' for protons into a similar 'n W/m' criteria for different heavy ions. For protons the scaling factor is obviously 1. Scaling factors for other ions depend on the charge number of the ion and on the beam energy. For example, for U ions with energy E = 200 MeV/u the scaling factor is 60, i.e. 60 W/m losses of U beam are tolerable from the 'hands-on' maintenance point of view, whereas for U ions with E=1 GeV/u the scaling factor is just 5. In the present paper we show that this scaling factor concept has natural limits of applicability. In the case of very low beam energies or in the case of long-term accumulation of the residual activity, the tolerable beam-loss criteria cannot be obtained by simple rescaling of the '1 W/m criterion' with one single number.

Experimental and simulation data concerning fragmentation of 238 U ion beam in aluminum, copper, and stainless-steel targets with the initial energy 500 and 950 MeV=u are collected in the paper. A rangeverification technique based on depth profiling of residual activity is presented. The irradiated targets were constructed in the stacked-foil geometry and analyzed using gamma-ray spectroscopy. One of the purposes of these experiments was depth profiling of residual activity of induced nuclides and projectile fragments. Among the projectile fragments, special attention is paid to the 237 U isotope that has a range very close to the range of the primary 238 U ions. Therefore, the depth profiling of the 237 U isotope can be utilized for experimental verification of the 238 U primary-beam range, which is demonstrated and discussed in the paper. The experimental data are compared with computer simulations by FLUKA, SRIM, and ATIMA, as well as with complementary experiments.

The operation of high power high brightness accelera- tors requires huge efforts for beam cleaning and machine protection. Within the WP 8 (ColMat) of the EU re- search framework EuCARD(1) we investigate new materi- als and methods for beam collimation and machine protec- tion. We present an overview of these activities at the GSI Helmholtzzentrum fur Schwerionenforschung, Darmstadt. Simulations of accidental beam losses in LHC and SIS100 have been performed. Scenarios for halo collima- tion of heavy ions and protons in SIS100 routine opera- tion have been investigated. A prototype of a cryogenic collimator for charge exchange losses during intermediate charge state heavy ion operation in SIS100 has been build and tested with beam. Several candidates of advanced com- posite materials for collimation system upgrades of present and future high power accelerators have been irradiated and their properties are being characterized. Most deliverables and milestones of the R&D pro- gramme were already reached before the end of the funding period.

I. Strašı́k, V. Chetvertkova, E. Mustafin, M. Pavlovič, and A. Belousov GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, D64291 Darmstadt, Germany IAP Goethe Universität Frankfurt am Main, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main, Germany FEI STU, Ilkovičova 3, SK-81219 Bratislava, Slovak Republic Technische Universität Darmstadt, Karolinenplatz 5, D-64289 Darmstadt, Germany (Received 18 October 2011; published 3 July 2012)

Various processes related to the beam dynamics can cause the beam halo formation which is one of the reasons for uncontrolled beam losses. The beam losses i nteract with the accelerator structure and can cause vario us problems such as: vacuum degradation due to desorption process, superconducting magnets quenches, activation of the accelerator structure, background in experiments or radiation damage of the equipment and devices [1]. The purpose of the halo collimation is to reduce above mentioned problems and to provide a well defined storing location for beam losses.