THVIR —  MC7 & MC8 Presentations   (14-May-20   09:00—16:00)
Paper Title Page
A 2MW Mercury Target for Neutron Production  
  • C.N. Barbier, E.E. Dominguez, K.C. Johns, J.R. Weinmeister, D.E. Winder
    ORNL, Oak Ridge, Tennessee, USA
  Funding: This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE).
Upgrades are underway at the Spallation Neutron Source at ORNL to increase the proton beam power from 1.4 MW to 2.8 MW to increase the neutron intensity at the first target station up to 2 MW and support the future operation of the second target station. The first target station uses a mercury target and its lifetime is mainly restricted by cavitation erosion: when the proton beam pulses hit the target, strong pressure waves are developed causing cavitation damage. A successful approach to mitigate the pressure wave has been to inject small helium bubbles into the mercury. Experience at SNS shows that even a small amount of Helium was enough to successfully mitigate the pressure wave and the cavitation erosion at 1.4 MW. However, at higher power more mitigation will be necessary. A substantially new design target vessel design will be presented that leverages lessons from operational experience and post-irradiation examination of previous targets. The 2MW target will be equipped with two methods of gas injection: swirl bubblers to introduce small bubbles and a second gas injection port closer to the nose. Operation history and R&D related to this new target will be presented.
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In-Situ Amorphous Carbon Coating of the Beam Screens of LHC’s Standalone Magnets  
  • P. Costa Pinto, V. Baglin, P. Chiggiato, A.R. Costa, P. Cruikshank, P. Demolon, S. Fiotakis, M. Himmerlich, H. Kos, N. Kos, G. Marinaro, M. Taborelli, J. Tagg, D.A. Zanin
    CERN, Geneva, Switzerland
  The heat load generated by the Electron Cloud (EC) in some superconducting magnets of the LHC has been recognized as a limiting factor for the operation of the High Luminosity LHC (HL-LHC). To overcome this problem, CERN launched a program to develop an "in-situ" coating technology to deploy amorphous carbon thin films - with a secondary electron yield below 1.1 - in the inner walls of the beam screens of selected magnets in the LHC tunnel. This includes the inner triplets for the two experiments in points 2 and 8, (ALICE and LHC-b), and some standalone magnets of their respective matching sections. In this work, we report on the first "in-situ" coating campaign that is being performed in Long Shutdown 2 (LS2, 2019-2020). The milestones of the R&D program are presented, namely achieving low secondary electron emission (by carbon and co-deposition of titanium); ensuring adhesion to the substrate (ion etching and titanium under layer); and implementing the mechanical setup to displace the sputtering source along 20 meters of beam screen in ultrahigh vacuum. The procedure is described as well as the main difficulties and achievements during the implementation in the tunnel.  
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Full Energy Beam Exploitation Beam Line on CLARA for Novel Applications  
  • D. Angal-Kalinin, M. Colling, J.K. Jones, E.W. Snedden
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • B.D. Fell
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • J.K. Jones
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  CLARA (Compact Linear Accelerator for Research and Applications) is a test facility for Free Electron Laser (FEL) research and other applications at Daresbury Laboratory. In order to provide full energy (250 MeV) beam to users for exploitation, a Full Energy Beam Exploitation (FEBE) line is designed to extract beam before the FEL section. The beamline consists of dogleg designed to cancel coherent synchrotron radiation (CSR) for a compressed start-to-end bunch and can also be used to compress bunch to avoid CSR blow up in the main beam line before beam is diverted to FEBE line. Following user consultation, we have developed the design to allow beam experiments combining electron beam, laser and jet target experiments. The design incorporates flexibility to re-configure experiments easily and incorporates number of diagnostics pre and post the interaction point. We present design of this beamline with tracked bunch parameters at different charges to deliver range of parameters to users.  
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Global Production of SRF Systems  
  • P. Zhang
    IHEP, Beijing, People’s Republic of China
  Many large accelerator facilities are based on superconducting RF technology. Sophisticated but meanwhile well established technical platforms are used. The exchange of knowledge and more and more the sharing of infrastructure is key to success. The world-wide network of platforms and the links between recent large projects will be described. Both long-established efforts as well as new and emerging efforts e.g. in China, will be described, based on material collected from colleagues around the world. The need of sustained operation will be highlighted.  
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SIS100 Dipoles From Design to Testing of Series Magnets  
  • A. Szwangruber, P. Aguar Bartolome, A. Bleile, E.S. Fischer, F. Kaether, J. Ketter, F. Kurian, J.P. Meier, S.S. Mohite, C. Roux, P.J. Spiller, K. Sugita, P.B. Szwangruber, A. Warth, A. Zaghloul
    GSI, Darmstadt, Germany
  The international Facility for Antiproton and Ion research (FAIR) is currently under construction in Darmstadt, Germany. The magnet system of the main accelerator SIS100 utilises 415 fast-cycling superconducting magnets which were designed at GSI and contracted either at industry or by collaboration partners. The production of series dipole magnets started in November 2016 with the first magnet delivered in September 2017. The main steps on the way from the magnet design to series production including selected aspects of fabrication will be presented. Furthermore, an overview of acceptance tests and measurement results for main operational parameters will be shown.  
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RF Test Results of a Superconducting Cavity Cooled by a Cryocooler  
  • G. Ciovati, G. Cheng, K.A. Harding, R.A. Rimmer
    JLab, Newport News, Virginia, USA
  Funding: Work supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and by G. C. 2008 PECASE award.
The convergence of high-quality Nb3Sn film coatings and cryocoolers with more than 1 W of cooling power at 4 K, makes it possible to envision superconducting radiofrequency cavities operating at accelerating gradients of the order of 10 MV/m, cooled by conduction with a crycooler rather than by contact with a liquid He bath. Such possibility might open the possibility of applying the SRF technology to industrial accelerators. This contribution describes the design of a test stand for conduction cooling experiments and the rf test results of a 1.5 GHz single-cell cavity cooled using a single cryocooler.
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Plasma Processing to Reduce Field Emission in LCLS-II 1.3 GHz SRF Cavities  
  • B. Giaccone, P. Berrutti, M. Martinello
    Fermilab, Batavia, Illinois, USA
  • B. Giaccone
    IIT, Chicago, Illinois, USA
  A collaboration between FNAL, SLAC and ORNL is working to develop plasma processing for 1.3GHz LCLS-II cavities. Key strength of this technique is that it can be applied in situ inside the cryomodule to mitigate field emission due to hydrocarbon contamination. A new method that uses Higher Order Modes has been developed at FNAL for plasma ignition and plasma transfer inside the 9-cell cavity. Plasma processing has been applied to multiple single cell and 9-cell cavities showing positive results; its effectiveness is discussed in terms of Q and Radiation vs E performance before and after processing.  
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High Efficient GaN/SiC Solid-State Technology for 1.3GHz Superconducting Cavity RF Power Source  
  • H.S. Jeong, S. Cho, H. Jung, B.G. Kang, H.J. Yoo, T.S. Yoon
    RFHIC, GyeongGi-Do, Republic of Korea
  The conventional RF power source of the accelerator, Klystron, has been used for a long time. Now, the solid-state technology is getting spotlight because of its competitive cost, easy maintenance, low/safe power supply voltage. Although LDMOS transistors are commonly known in the accelerator field, Gallium Nitride on Silicon Carbide or GaN/SiC transistor has proven its superior RF performances, higher efficiency, and smaller size in the telecom and the military field. RFHIC introduces a new GaN/SiC transistor which is specialized for 1.3GHz superconducting cavity RF power source. It maximizes its efficiency, 80%, with efficiency-contour matching techniques at 550W CW, using two 41.8mm gate-width GaN/SiC dies. The transistor is simulated with ADS, and the load-pull test verifies its performance. This transistor is utilized in designing a 2kW solid-state power amplifier with 70% efficiency. It consists of four 550W transistors with T-junction combining technology. Indeed, it contains accurate power monitoring and reflected power protection circuits. The ultimate goal of this 1.3GHz GaN/SiC solid-state technology is to replace current CW klystron up to several hundred kW.  
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Magnetic Measurements and Fiducialisation of the ESRF-EBS Magnets  
  • G. Le Bec, J. Chavanne, L. Lefebvre, D. Martin, C. Penel
    ESRF, Grenoble, France
  The Extremely Brilliant Source (EBS) is a low emittance storage ring based lightsource installed at the ESRF. The EBS storage ring is built with more than one thousand small aperture magnets, including dipoles with stair-like field profile, combined dipole-quadrupoles, high gradient quadrupoles and higher order multipole magnets. All of these magnets were magnetically characterized and fiducialised with Moving Stretched-Wire (MSW) measurement benches developed at the ESRF. The multipole strengths of all magnets, including curved combine magnets, were obtained from MSW measurements. A detailed fiducialisation uncertainty analysis was made and estimated to about 20 µm for the bench and 33 µm when the mechanical shimming of the magnet axis is taken into account. Measurement and fiducialisation statistics will be shown and compared to design expectations.  
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Cryogenic-Copper Accelerating Structures: New Frontier for Beam Brightness, Efficiency and Cost-Capability  
  • M.H. Nasr, M. Breidenbach, E.A. Nanni, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  The operation of normal conducting (NC) linacs at cryogenic temperatures creates new frontiers of ultra-high gradient performance of accelerator structure. Reducing the operating temperature of NC linacs to cryogenic-temperature decreases the surface resistance compared to room-temperature operation. This results in large increase in the shunt impedance and the intrinsic quality factor of the cavity, which enables higher gradient operation as well as increased beam loading capabilities. Moreover, low temperature operation increases surface hardness and results in large reduction in breakdown rates compared to room-temperature operation. We are experimentally investigating the operation of an X-band, 20 cells, standing wave, linac at LN temperature of 77k. This structure was previously processed and tested at room-temperature for reference. Operating with LN results in much reduced cost compared to the complicated setup required for operation with LHe, and still provides much enhanced characteristics of NC accelerator structures. In this paper, we will present the experimental setup and initial measurement results of our NC linac testing at cryogenic-temperature at SLAC.  
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Introduction to 3D Printing Techniques for Accelerator Vacuum Systems  
  • T. Ha, S.H. Kim, C.D. Park, S. Shin
    PAL, Pohang, Republic of Korea
  • HG. Kim, H.K. Park
    KITECH, Gangneung, Republic of Korea
  A large variety of small aperture magnets is required for modern low emittance storage rings. These magnets restrict the flexibility of the vacuum system. The low conductance of the vacuum chamber together with the small aperture is the main limiting factor for achieving the required vacuum performance. In addition it is challenging to accommodate high heat loads from synchrotron radiation because of the tight space available for the vacuum parts. Metal 3D printing techniques for vacuum system components of 4th generation storage ring (4GSR) could mitigate some of the difficulties. An overview of the world-wide status, the expected benefits and the challenges of 3D printing techniques for accelerator vacuum systems is presented. Projects at existing and future synchrotron facilities are described. One example is the design of the vacuum system for the PAL-4GSR at Pohang Accelerator Laboratory (PAL), which includes 3D printed NEGs for distributed pumping and a compact sputter ion pump with 3D printed anode structures.  
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THVIR12 FLASH Radiation Therapy: Accelerator Aspects 71
  • A. Patriarca, L. De Marzi, V. Favaudon, S.J. Meyroneinc
    Institut Curie - Centre de Protonthérapie d’Orsay, Orsay, France
  One of the new paradigms in radiation therapy (RT) is the FLASH dose delivery irradiation technique. The FLASH methodology consists in delivering millisecond pulses of radiation (total beam-on time < 100-500 ms) delivered at a high mean dose-rate (> 40-100 Gy/s) and pulse amplitude (> 106 Gy/s), over 2000 times faster than in conventional RT. New accelerator ideas are under development or are being tested to deliver this type of beam. In this paper we will report the accelerator technology used for the pre-clinical studies and the necessary developments to deliver this novel dose RT technique.  
DOI • reference for this paper ※  
About • paper received ※ 01 June 2020       paper accepted ※ 12 June 2020       issue date ※ 10 October 2020  
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THVIR13 CERN-MEDICIS: A Unique Facility for the Production of Non-Conventional Radionuclides for the Medical Research 75
  • C. Duchemin, T. Stora
    CERN, Meyrin, Switzerland
  • J.P. Ramos
    SCK•CEN, Mol, Belgium
  The MEDICIS facility is a unique facility located at CERN dedicated to the production of non-conventional radionuclides for research and development in imaging, diagnostics and radiation therapy. It exploits in a Class A work sector, a dedicated isotope separator beam line, a target irradiation station at the 1.4 GeV Proton Synchroton Booster (PSB) and receives activated targets from external institutes during CERN Long Shut-Downs. The target is heated up at high temperatures to allow for the diffusion and effusion of the atoms out of the target that are subsequently ionized. The ions are accelerated and sent through an off-line mass separator. The radionuclide of interest is extracted through mass separation and implanted into a thin metallic collection foil. After collection, the batch is prepared to be dispatched to a research center. In the near-future, the radiochemistry process will also be performed in MEDICIS. Since its commissioning in December 2017, the facility has provided novel radionuclides such as Tb-149, Tb-155, Tm-165, Er-169 and Yb-175 with high specific activity, some for the first time, to European research institutes part of the collaboration.  
DOI • reference for this paper ※  
About • paper received ※ 09 June 2020       paper accepted ※ 12 June 2020       issue date ※ 10 October 2020  
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THVIR14 Development of a Hybrid Electron Accelerator System for the Treatment of Marine Diesel Exhaust Gases 80
  • T. Torims, K. Kravalis, G. Pikurs, A. Ruse
    Riga Technical University, Riga, Latvia
  • A.G. Chmielewski, A. Pawelec, Z. Zimek
    Institute of Nuclear Chemistry and Technology, Warsaw, Poland
  • G. Mattausch
    Fraunhofer FEP, Dresden, Germany
  • M. Vretenar
    CERN, Meyrin, Switzerland
  Funding: This project has received funding from the European Union¿s Horizon 2020 Research and Innovation programme under Grant Agreement No 730871
Project seeks to tackle the shipping industry’s most pressing problem, its large-scale emissions of SOx, NO and PM, by developing a hybrid exhaust gas-cleaning technology that combines an EB accelerator with improved wet-scrubbing technology. It is unique - in a single technological system - addresses all three types of emissions simultaneously. It promises to be cheaper and more efficient than existing solutions. There are two main stages involved: 1) SO2 and NOx oxidation during irradiation of wet gases by the EB from the accelerator and 2) the pollution products absorption into aqueous solution. For the very first time, test trials in the real maritime environment where conducted and attracted interest of maritime industry, policy makers and accelerator community. Proof-of-Concept clearly confirmed potential of this accelerator technology and formed basis for the full-scale project where this hybrid system will be applied to the sea-going ferry on the regular traffic. Considering that this project is of highest relevance to the accelerator community at large, we will be happy to present it and disseminate its promising results along with the related unfolding activities.
DOI • reference for this paper ※  
About • paper received ※ 01 June 2020       paper accepted ※ 11 June 2020       issue date ※ 10 October 2020  
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THVIR15 Accelerators for Applications in Energy and Nuclear Waste Transmutation 86
  • A. Fabich
    EBG MedAustron, Wr. Neustadt, Austria
  • H. Ait Abderrahim, U. Dorda, D. Vandeplassche
    SCK•CEN, Mol, Belgium
  Accelerator Driven Systems (ADS) is a concept using high power proton accelerators in energy production and nuclear waste transmutation. Amongst typical beam performance requirements, the operational reliability of the accelerator is exceptionally demanding. The advantages and challenges of different driver options, like cyclotrons and linacs, are evaluated and worldwide design studies are summarized. The MYRRHA design is based on a 600 MeV superconducting proton linac. The first stage towards its realization was recently approved to be constructed by SCK•CEN in Belgium. The 100 MeV linac will serve as technology demonstrator for MYRRHA as well as driver for independent two target stations, one for fusion material research and one for research and medical isotope production. MYRRHA in its final implementation is envisaged as an international collaboration.  
DOI • reference for this paper ※  
About • paper received ※ 29 May 2020       paper accepted ※ 09 October 2020       issue date ※ 10 October 2020  
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