Keyword: ECR
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MOPGW064 On Wakefield in Dielectric Waveguide with Shallow Corrugation of Metallic Wall GUI, radiation, wakefield, impedance 237
 
  • A.V. Tyukhtin, E.R. Akhmatova, T.Yu. Alekhina, S.N. Galyamin, V.V. Vorobev
    Saint Petersburg State University, Saint Petersburg, Russia
 
  Funding: This work was supported by the Russian Science Foundation (Grant # 18-72-10137).
Bunch radiation in periodical waveguides was mainly analyzed for situations when wavelengths are comparable to the structure period (Smith-Purcell emission). However, it is also of interest to study the "long-wave radiation" with wavelengths which are much larger than the structure period*,**. In such situation, the exact boundary conditions on the complicated periodic surface can be replaced with the equivalent boundary conditions (EBC) which must be fulfilled on the smooth surface. Earlier we considered with this approach radiation of the bunch moving along the axis of circular vacuum corrugated waveguide**. Comparison of analytical results with COMSOL simulations showed high accuracy of the EBC method. Here we analyze an analogous problem for the waveguide with corrugated wall and dielectric filling under condition that Cherenkov effect takes place in the dielectric. Due to this fact the radiation differs radically from that in the vacuum waveguide. At the same time, the radiation has essential differences from the one in the usual dielectric waveguide. The radiation properties in the waveguide under consideration and its differences from the radiation in the waveguide with smooth wall are analyzed.
* G. Stupakov, K. Bane, Phys. Rev. ST-AB, 15 (2012) 124401.
** A.V. Tyukhtin et al, J. of Instrumentation, 13 (2018) C04009.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW064  
About • paper received ※ 15 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPMP007 Design of a Compact Power Distribution System for the ILC cavity, cryomodule, acceleration, collider 436
 
  • B. Du, N. Liu
    Sokendai - Hayama, Hayama, Japan
  • T. Matsumoto, S. Michizono, T. Miura, F. Qiu
    KEK, Ibaraki, Japan
  • T. Matsumoto, T. Miura, F. Qiu
    Sokendai, Ibaraki, Japan
 
  The Local power distribution system (LPDS) of the In-ternational Linear Collider (ILC) is constructed to transmit RF power from the 10 MW klystron to 39 cavi-ties. Each eight or nine 9-cell cavities is assembled in one cryomodule. The variable hybrid is used to adjust the power dividing ratio due to the different required power of each cavity and the variable phase shifter is used to compensate the phase drift caused by the variable hybrid. More compact LPDS is expected to be integrated on the cryomodule decreasing financial cost. We re-design the shorter variable hybrid with a margin of power ratio of ±25% and phase shifter of total phase range being 35° for compensating hybrid and on-crest searching. Fixed phase shifters are designed to adjust the phase difference between adjacent cavities for beam acceleration. Simu-lated results of total compact LPDS can meet the re-quirements of ILC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP007  
About • paper received ※ 16 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS072 RF DESIGN OF AN 81.25 MHz BENT-VANE TYPE RFQ rfq, cavity, linac, simulation 1015
 
  • L. Yang, T. He, Y. He, L. Lu, C.C. Xing, L. Yang
    IMP/CAS, Lanzhou, People’s Republic of China
  • A.H. Li
    IHEP, Beijing, People’s Republic of China
 
  The bent-vane type RFQ is proposed at IMP, Chinese Academy of Sciences, which can downsize cross section and has the simple cooling system in low frequency field. The vanes of the four-vane type RFQ are bent to form the new RFQ structure. In order to research its RF properties, the prototype cavity of an 81.25 MHZ bent-vane type RFQ is designed. This paper presents the preliminary RF design of the prototype cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS072  
About • paper received ※ 17 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPTS081 Design of the Transferline to the ESS Target and Beam Dump at Reduced Beam Energy target, linac, quadrupole, ion-source 1034
 
  • Y.S. Qin, M. Eshraqi, Y. Levinsen, R. Miyamoto
    ESS, Lund, Sweden
 
  The European Spallation Source (ESS) linac transfer-lines to the target and beam dump are designed for the 2 GeV beam energy. The commissioning and operation of the accelerator will start at a reduced energy of 571 MeV with the high beta part of the linac unpowered. The beam power at this energy is still above 1 MW and a proper transport from the last accelerating cavity to the target is essential. Beam dynamics design of the High Energy Beam Transport (HEBT) and Accelerator to Target (A2T) are studied based on this reduced energy in this paper, including phase advance optimization and rematch. Among the factors which are analyzed are the envelope and beam size on the target which are kept close to their values at 2 GeV and losses along the linac and the transfer lines.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS081  
About • paper received ※ 10 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPMP004 Dynamic Pressure in the LHC - Influence of Ions Induced by Ionization of Residual Gas by Both the Proton Beam and the Electron Cloud electron, proton, vacuum, experiment 1236
 
  • S. Bilgen, C. Bruni, B. Mercier, G. Sattonnay
    LAL, Orsay, France
  • V. Baglin
    CERN, Geneva, Switzerland
 
  Funding: work supported by FCC project (CERN & LAL-CNRS-IN2P3)
Ultra-High Vacuum is an essential requirement to reach design performances in high-energy particle colliders. For the future HL-LHC or FCC study, the understanding of the beam interactions with the vacuum chamber is fundamental to provide solutions to mitigate the pressure rises induced by electronic, photonic and ionic molecular desorption. Studies were performed on the ions, produced by molecular ionization generated by the proton beam and the electron cloud, and stimulating molecular desorption by the surface bombardment. In-situ measurements were carried out, on the LHC Vacuum Pilot Sector (VPS)*, to monitor the dynamic pressure, and to collect the electrical signals due to the electron cloud and to the ions interacting with the vacuum chamber walls. Experimental measurements of electrical signals recorded by copper electrodes were compared to calculations taking into account both the Secondary Electron Yield of copper and electron energy distribution. Finally, it seems that copper electrodes were not fully conditioned and an ion current could be estimated.
* THE LHC VACUUM PILOT-SECTOR PROJECT
B. Henrist, V. Baglin, G. Bregliozzi, and P. Chiggiato, CERN, Geneva, Switzerland
Proceedings of IPAC2014, Dresden, Germany.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP004  
About • paper received ※ 01 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPMP042 The Beam Cleaning Analysis for the TPS Vacuum System vacuum, MMI, radiation, operation 1344
 
  • Y.C. Yang, C.K. Chan, C.-C. Chang, A.Y. Chen, J.-Y. Chuang, C.H. Huang
    NSRRC, Hsinchu, Taiwan
 
  Commissioning for the TPS, a low-emittance 3-GeV synchrotron ring, started in December 2014 and is now currently operating in top-up mode at 400mA for users. Until the last machine shut down in December 2018, a total beam dose of 4919 Ah was accumulated and the beam cleaning effect decreased the dynamic pressure to 1.5×10-11 Pa/mA. During past years operation, several vacuum chambers were replaced to improve vacuum performance and avoid exposure to synchrotron radiation from insertion devices. In this paper, the beam cleaning evolution of new vacuum sections will be discussed and compared with experience in the rest of the storage ring. A particular cleaning evolution could be predicted and can be referenced for machine shutdown planning in the future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP042  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW064 Trials of Beam-Based Sextupole Calibration through 2nd Order Dispersion sextupole, storage-ring, optics, lattice 1551
 
  • D.K. Olsson, Å. Andersson, M. Sjöström
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  In order to achieve nominal performance in terms of the dynamic aperture and lifetime of a storage ring, it is important to be able to characterise and correct its second order optics. At the MAX IV 3 GeV storage ring in Lund, Sweden, the linearity of the 2nd order dispersion with chromatic sextupole field strengths has been utilised to investigate the sextupole circuits. The beating induced in the 2nd order dispersion when reducing the strength of a sextupole magnet can be compared to the beating in simulations. From this a beam-based sextupole calibration curve can be found. This work was inspired by similar work done at ESRF.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW064  
About • paper received ※ 13 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPGW106 Present Status of the PF-ring and PF-AR Operations operation, injection, photon, undulator 1654
 
  • R. Takai, T. Honda, Y. Kobayashi, S. Nagahashi
    KEK, Ibaraki, Japan
 
  The Photon Factory at KEK has been managing two synchrotron radiation sources, the PF-ring and PF-AR, for over 30 years. Although their operation time has been decreasing in recent years for budget reasons, continuous efforts to improve their performance have been made. In this paper, the operational status of these light sources for FY2018 is described. At the PF-ring, a first-generation undulator was renewed with the beamline components. A vacuum chamber for the new undulator was applied the NEG coating on the inner surface. This is the first attempt in Japanese light sources that the NEG-coated chamber is used for undulators. At the PF-AR, the top-up injection using the direct beam transport line was introduced to the user operation for the first time. Since modification of the beam injector LINAC for enabling simultaneous injection to the four different rings (the PF-ring, PF-AR, SuperKEKB HER and LER) was completed, this top-up operation no longer disturbs the operation of the other three rings. A low-energy operation of the PF-AR was also tested to secure more operation time within the limited budget.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW106  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPTS070 Systematic Benchmarking of a Planar (N)UNCD Field Emission Cathode cathode, gun, experiment, electron 2083
 
  • J.H. Shao, M.E. Conde, W. Liu, J.G. Power, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • S.V. Baryshev, M.S. Schneider
    Michigan State University, East Lansing, Michigan, USA
  • G. Chen
    IIT, Chicago, Illinois, USA
  • K. Kovi
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • L.K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois, USA
 
  Planar nitrogen-incorporated ultrananocrystalline diamond, (N)UNCD, is a unique and attractive field emission source because of the capability to generate high charge beam, the simplicity of production without shaped emitters, and the ease of handling with moderate vacuum requirement. In the presented study using an L-band normal conducting single-cell rf gun, a (N)UNCD cathode has been conditioned to 42 MV/m with a well-controlled manner and reached a maximum charge of 15 nC and an average emission current of 6~mA during a 2.5 us emission period. The systematic study of emission properties during the rf conditioning process illustrates the tunability of (N)UNCD in a wide range of surface gradients. This research demonstrates the versatility of (N)UNCD cathode which could enable multiple designs of field emission rf injector for industrial and scientific applications.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS070  
About • paper received ※ 20 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPTS091 Physics of Electron Beam Generation and Dynamics From Diamond Field Emitter Arrays electron, simulation, cathode, experiment 2137
 
  • C. Huang, H.L. Andrews, R.C. Baker, R.L. Fleming, D. Kim, T.J. Kwan, V.N. Pavlenko, A. Piryatinski, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
 
  Funding: Work supported by the LDRD program at Los Alamos National Laboratory
Many applications such as compact accelerators and electron microscopy demand high brightness electron beams with small beam size and low emittance. Electric-field-assisted diamond emitters manufactured from semiconductor processes are strong candidates for cathodes in such sources. The micro-scale pyramid structure of the emitter has the desirable attribute of significant field enhancement at the sharp interfaces (apex and edges) to facilitate electron emission. We use the LSP particle-in-cell code to simulate the diamond emitter in a diode setup and obtain the beam size and divergence. An empirical fit of the fields around the apex is extracted for detail study. The trend of the beam divergence observed in the simulation is further corroborated using electron’s trajectory in the empirical field model.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS091  
About • paper received ※ 15 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEXPLS1 High Performance ECR Sources for Next-Generation Nuclear Science Facilities plasma, ion-source, ECRIS, electron 2224
 
  • D. Leitner
    LBNL, Berkeley, California, USA
 
  Modern heavy-ion accelerators require intense heavy-ion beams with high charge state. Electron Cyclotron Resonance (ECR) sources are the primary tool for generating such beams. Advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to significant improvements in ECR source performance over the last several decades. The current state of the art is represented by third-generation sources operating at frequencies around 28 GHz and peak coil fields of about 7 T using NbTi conductor. Fourth-generation ECR ion sources with an operating frequency above 40 GHz have the potential to quadruple the source output beam current. These sources will need to incorporate advanced conductor technologies and/or novel coil configurations in order to exceed the limitations of the present structures. This talk will present worldwide efforts currently underway to develop high-performance ECR sources using new design approaches in support of next-generation nuclear physics facilities.  
slides icon Slides WEXPLS1 [8.012 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEXPLS1  
About • paper received ※ 16 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEXXPLS3 Is it Possible to Use Additive Manufacturing for Accelerator UHV Beam Pipes? electron, vacuum, laser, experiment 2240
 
  • G. Sattonnay, M. Alves, S. Bilgen, B.J. Bonnis, A. Gonnin, D. Grasset, S. Jenzer, F. Letellier-Cohen, B. Mercier, E. Mistretta
    LAL, Orsay, France
  • F. Brisset
    ICMMO, Orsay, France
 
  Funding: Work supported by a grant from IN2P3/CNRS, program I3D metal
Recently, additive manufacturing (AM) has revolutionized mechanical engineering by allowing the quick production of mechanical components with complex shapes. AM by selective laser melting (SLM) is an advanced manufacturing process which uses lasers to melt metal powders one layer at a time to produce final 3D components. This technology could be also used to make Ultra High Vacuum components. Therefore, we investigated in this work the reproducibility of AM 316L stainless steel properties for different specimen supplied by several manufacturers with the same SLM process. Clearly, the microstructure and therefore the mechanical properties of the investigated AM samples are different as a function of manufacturers: indeed, they are largely influenced by processing parameters, which produces heterogeneous and anisotropic microstructures that differ from traditional wrought counterparts. Samples were also submitted to bake cycles at high temperature, in order to check the structural stability of material properties after heat treatments. The outgassing rates and the secondary emission yield of vacuum components constructed from AM 316L were also measured. Finally, the possibility to use AM for accelerator beam pipes will be discussed.
 
slides icon Slides WEXXPLS3 [9.009 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEXXPLS3  
About • paper received ※ 01 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPMP028 Crystal for Slow Extraction Loss-Reduction of the SPS Electrostatic Septum extraction, proton, experiment, alignment 2379
 
  • L.S. Esposito, P. Bestman, M.E.J. Butcher, M. Calviani, M. Di Castro, M. Donzé, M.A. Fraser, M. Garattini, Y. Gavrikov, S.S. Gilardoni, B. Goddard, V. Kain, J. Lendaro, A. Masi, M. Pari, J. Prieto, R. Rossi, W. Scandale, R. Seidenbinder, P. Serrano Galvez, L.S. Stoel, F.M. Velotti, V. Zhovkovska
    CERN, Geneva, Switzerland
  • F.M. Addesa, F. Iacoangeli
    INFN-Roma, Roma, Italy
  • A.G. Afonin, Y.A. Chesnokov, A.A. Durum, V.A. Maisheev, Yu.E. Sandomirskiy, A.A. Yanovich
    IHEP, Moscow Region, Russia
  • J.E. Borg, M. Garattini, G. Hall, T. James, M. Pesaresi
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • A.S. Denisov, Y. Gavrikov, Yu.M. Ivanov, M.A. Koznov, L.G. Malyarenko, V. Skorobogatov
    PNPI, Gatchina, Leningrad District, Russia
  • F. Galluccio
    INFN-Napoli, Napoli, Italy
  • A.D. Kovalenko, A.M. Taratin
    JINR, Dubna, Moscow Region, Russia
  • F. Murtas
    INFN/LNF, Frascati, Italy
  • A. Natochii
    LAL, Orsay, France
 
  The use of a bent crystal was investigated in order to reduce the losses at the CERN Super Proton Synchrotron (SPS) electrostatic septa (ZS) during the slow extraction of 400 GeV protons toward the North Area. The crystal, installed a few meters upstream the ZS, bends protons that would otherwise impinge on the ZS wires. Since particle deflection with good efficiency is achieved only when the crystal lattice is aligned within ~10 urad to the trajectory of the particles (at p = 400 GeV/c), a compact goniometer was built to allow the correct angular alignment of the crystal with respect to the incoming beam with a precision of few urad. In this paper, we report on the crystal features measured during a dedicated beam test by the UA9 experimental installation in the CERN H8 beam line. Details of the goniometer and its installation are also reported. The first results achieved during dedicated Machine Development (MD) sessions are finally presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP028  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPGW081 Unsupervised Machine Learning for Detection of Faulty Beam Position Monitors optics, simulation, ISOL, MMI 2668
 
  • E. Fol, J.M. Coello de Portugal, R. Tomás
    CERN, Meyrin, Switzerland
 
  Unsupervised learning includes anomaly detection techniques that are suitable for the detection of unusual events such as instrumentation faults in particle accelerators. In this work we present the application of decision trees-based algorithm to faulty BPMs detection at the LHC. This method achieves significant improvements in quality of optics measurements and allows to identify relevant signal properties that contribute to fault detection.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW081  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPGW088 Characterisation of Electro-Optic Pickups for High Bandwidth Diagnostics at the High Luminosity LHC pick-up, simulation, proton, luminosity 2690
 
  • A. Arteche, A. Bosco, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • S.E. Bashforth, A. Bosco, S.M. Gibson, I.S. Penman
    JAI, Egham, Surrey, United Kingdom
  • M. Krupa, T. Lefèvre
    CERN, Geneva, Switzerland
 
  Funding: Work supported by UK STFC grants ST/N001583/1, JAI at Royal Holloway University of London and CERN.
A high bandwidth electro-optical beam position monitor is under development for the High Luminosity LHC. A series of measurements of the electro-optic signals were previously obtained by an EO-BPM prototype installed in the SPS. This paper focuses on an advanced design that would further improve the sensitivity of the pick-up by optimising the shape of the metallic electrode mounted onto the crystal. The proposed upgraded electro-optic pickups significantly increase the image field profile of the passing bunch inside a lithium niobate crystal embedded within the pickup. This work is based on parametric studies, performed using CST particle studio, investigating various electro-optic (electrode and crystal) configurations. We present the expected performance of the different designs, alongside with their evaluation on a test bench, highlighting the most relevant choice for a prototype pick-up to be installed on LHC
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW088  
About • paper received ※ 22 May 2019       paper accepted ※ 24 May 2019       issue date ※ 21 June 2019  
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WEPRB047 High-Power Test of a 12 Cell Accelerating Structure Build in Halves klystron, vacuum, shielding, GUI 2912
 
  • M.M. Peng, Y.L. Jiang, J.Y. Liu, Z.N. Liu, X.C. Meng, J. Shi, H. Zha
    TUB, Beijing, People’s Republic of China
 
  An X-band 12 cell travelling-wave accelerating structure has been developed and high-power tested at Tsinghua University in China. This structure works at 2⁄3 π at the frequency of 11.424 GHz. It is a 12-cell constant-impedance structure build in halves and was silver-brazed as a vacuum tight structure. The high power test was conducted at Tsinghua X-band high power test facility [1] with a 50-MW X-band klystron at a repetition rate to 40 Hz. The final input power was 51.23 MW with a 200 ns pulse width, which means an accelerating gradient of 88.58 MV/m was reached. This paper presents the high power test results including the gradient and breakdown history.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB047  
About • paper received ※ 10 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPRB059 Dark Current Analysis at CERN’s X-band Facility radiation, operation, electron, linac 2944
 
  • D. Banon-Caballero, M. Boronat, V. Sánchez Sebastián, A. Vnuchenko
    IFIC, Valencia, Spain
  • N. Catalán Lasheras, S. Pitman, M. Widorski, W. Wuensch, V. del Pozo Romano
    CERN, Meyrin, Switzerland
  • A. Faus-Golfe
    LAL, Orsay, France
  • B. Gimeno
    UVEG, Burjasot (Valencia), Spain
  • T.G. Lucas, M. Volpi
    The University of Melbourne, Melbourne, Victoria, Australia
  • W.L. Millar
    Lancaster University, Lancaster, United Kingdom
  • J. Paszkiewicz
    University of Oxford, Oxford, United Kingdom
 
  Dark current is particularly relevant during operation in high-gradient linear accelerators. Resulting from the capture of field emitted electrons, dark current produces additional radiation that needs to be accounted for in experiments. In this paper, an analysis of dark current is presented for four accelerating structures that were tested and conditioned in CERN’s X-band test facility for CLIC. The dependence on power, and therefore on accelerating gradient, of the dark current signals is presented. The Fowler-Nordheim equation for field emission seems to be in accordance with the experimental data. Moreover, the analysis shows that the current intensity decreases as a function of time due to conditioning, but discrete jumps in the dark current signals are present, probably caused by breakdown events that change the emitters’ location and intensity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB059  
About • paper received ※ 10 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPRB114 Understanding and Pushing the Limits of Nitrogen Doping cavity, SRF, niobium, experiment 3078
 
  • D. Bafia, M. Checchin, A. Grassellino, M. Martinello, O.S. Melnychuk, S. Posen, A.S. Romanenko, D.A. Sergatskov
    Fermilab, Batavia, Illinois, USA
  • D. Bafia, J. Zasadzinski
    IIT, Chicago, Illinois, USA
  • D. Gonnella
    SLAC, Menlo Park, California, USA
  • A.D. Palczewski
    JLab, Newport News, Virginia, USA
 
  This work will describe Fermilab experiments that focus on the optimization of doping parameters to achieve low sensitivity to trapped magnetic flux while maintaining very high Q characteristic of nitrogen doped cavities and same or higher quench fields. Working partially in the context of LCLS-2 higher energy upgrade, new doping recipes are pursued and have been found to vary the mean free path of the resonator which is related to the sensitivity to trapped magnetic flux. Moreover, a correlation has been found between lighter doping and higher quench fields while maintaining sufficiently low surface resistance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB114  
About • paper received ※ 18 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPTS082 Luminosity Studies of Asymmetric Crab Crossing in JLEIC luminosity, collider, electron, cavity 3311
 
  • E.A. Nissen
    JLab, Newport News, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, world-wide license to publish or reproduce this manuscript.
The proposed Jefferson Lab Electron Ion Collider (JLE-IC) currently plans to use a crab crossing scheme to max-imize the available luminosity. It had been suggested that space and cost savings, as well as hadron beam quality improvements, could be realized by leaving the ion beam un-crabbed and increasing the crabbing angle of the elec-tron beam. This and variations in-between equal and totally one-sided crabbing are examined for both JLEIC and LHC parameters, with various changes in crabbing angle and frequency studied to maximize luminosity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS082  
About • paper received ※ 14 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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THPGW030 Towards the First Beams from the ADIGE Injector for the SPES Project plasma, injection, ion-source, instrumentation 3647
 
  • A. Galatà, L. Bellan, J. Bermudez, G. Bisoffi, D. Bortolato, M. Comunian, A. Conte, M. De Lazzari, P. Francescon, F. Gelain, D. Marcato, M.O. Miglioranza, M.F. Moisio, E. Munaron, S. Pavinato, D. Pedretti, A. Pisent, M. Roetta, C. R. Roncolato, M. Rossignoli, G. Savarese
    INFN/LNL, Legnaro (PD), Italy
  • V. Andreev
    ITEP, Moscow, Russia
  • J. Angot, D. Bondoux, T. Thuillier
    LPSC, Grenoble Cedex, France
  • M.A. Bellato
    INFN- Sez. di Padova, Padova, Italy
 
  The ADIGE (Acceleratore Di Ioni a Grande carica Esotici) injector of the SPES (Selective Production of Exotic Species) project is now in an advanced phase of installation. Its main components have been designed following particular needs of the project: first, an Electron Cyclotron Resonance (ECR)-based Charge Breeder (SPES-CB), to boost the charge states of the radioactive ions produced at SPES and allow their post-acceleration. Then, a stable 1+ source and a complete electrostatic beam line to characterize the SPES-CB. Finally, a unique Medium Resolution Mass Spectrometer (MRMS, R=1/1000), mounted on a high voltage platform downstream the SPES-CB, to clean the radioactive beam from the contaminants induced by the breeding stage. This contribution describes the status of the injector, in particular the installation of the platform housing the MRMS, the access and safety system adopted and the first beams to be extracted from the stable 1+ source.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW030  
About • paper received ※ 30 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPGW058 Design and Study of a 6 Degree-Of-Freedom Universal Adjustment Platform for HL-LHC Components alignment, radiation, operation, target 3720
 
  • M. Sosin, T. Blaszczyk, A. Herty, J. Jaros, H. Mainaud Durand
    CERN, Meyrin, Switzerland
 
  In the accelerator domain, the safe and easy alignment of components located in radioactive areas, is a main concern. The position of devices, such as magnets and collimators, has to be adjusted in a fast and ergonomic way to decrease the ionizing dose received by the personnel. Each equipment type has its own unique set of requirements such as the weight, or the desired position accuracy. The two opposite approaches are, on one hand, a simple and time-consuming manual adjustment, using regulating screws and shims, and, on the other hand, the use of precise and expensive automatic positioning stages and platforms. In the frame of the High Luminosity LHC project, in order to fulfill the safety and technical requirements of alignment for lightweight components, a standardized system is under development. It will provide easy, low-cost and fast adjustment capability for several types of components that could be embarked on it. This paper describes the design, the study and the test results of such a universal adjustment solution. The engineering approach, the lessons learned, the issues and the mechanical components behavior are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW058  
About • paper received ※ 10 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPRB055 DAMAGE BEHAVIOR OF TUNGSTEN TARGETS FOR 6 MEV LINEAR ACCELERATORS target, experiment, electron, controls 3934
 
  • Z.H. Wang, Z.N. Liu, J. Shi, H. Zha
    TUB, Beijing, People’s Republic of China
 
  The target in electron linear accelerator is subjected to high-frequency and intense thermal shocks. Elevated temperatures in the target may lead to target recrystallization, fatigue cracking, creep and vaporization. In this study, experiments were carried out to investigate the damage behaviour of tungsten targets in 6 MeV linear accelerators under pulsed electron beam. The results show that recrystallization occurs after loading 6 MeV electron beam with repetition frequency of 220 Hz, pulse width of 4μs and mean current of 151μA for 248 s. Deformation and cracking caused by recrystallization are observed on the surface of the target.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB055  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPRB083 Detailed Analysis Of The Baseline Dose Levels And Localized Radiation Spikes In The Arc Sections Of The Large Hadron Collider During Run 2 radiation, operation, experiment, monitoring 4009
 
  • K. Bilko, M. Brugger, R. Garcia Alia, F.J. Harden, Y. Kadi, O. Stein
    CERN, Geneva, Switzerland
 
  The Large Hadron Collider (LHC) has eight insertion regions (IRs) which house the large experiments or accelerator equipment. These IRs are interconnected with the arc sections consisting of a periodic magnet structure. During the operation of the LHC small amounts of the beam particles are lost, creating prompt radiation fields in the accelerator tunnels and the adjacent caverns. One of the main loss mechanisms in the LHC arc sections is the interaction of the beam particles with the residual gas molecules. The analysis of the dose levels based on the beam loss measurement data shows that the majority of the measurements have similar levels, which allow to define baseline values for each arc section. The baseline levels decreased during the years 2015, 2016 and stabilised in 2017 and 2018 at annual dose levels below 50 mGy, which can be correlated with the residual gas densities in the LHC arcs. In some location of the arcs radiation spikes exceed the base line by more than two orders of magnitude. In addition to the analysis of these dose levels, a novel approach of identifying local dose maxima and the main driving mechanisms creating these radiation spikes will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB083  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPRB087 Study of the Energy Savings Resulting from the East Area Renovation experiment, operation, power-supply, radiation 4023
 
  • B. LM. Lamaille, F. Dragoni, S. Evrard, F.J. Harden, E. Harrouch, M. Lazzaroni, R. Lopez, K.D. Papastergiou
    CERN, Meyrin, Switzerland
 
  CERN’s East Experimental Area, situated on the Swiss side of the Meyrin site, with its four beamlines, has served physics for more than 40 years. As the building and equipment are reaching their end of life, a thorough consolidation project has been initiated in order to pro-vide many more years of reliable operation. This article addresses the different proposed solutions to reduce significantly the energy consumption of the East Area. It outlines the methodology applied to estimate as precisely as possible the future attained energy savings, which will result in an estimated reduction of approximately 80% in electricity usage (from 11 GWh to 2 GWh per year) and of approximately 65% in gas usage for heating purpose (from 3 GWh to 1 GWh per year).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB087  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPRB118 Study on the Influence of the Range Shifter Material in a Scanning Nozzle for Proton Therapy Based on Monte Carlo Method proton, neutron, scattering, radiation 4100
 
  • Y.C. Yu, H.D. Guo, Y.Y. Hu, X.Y. Li, Y.J. Lin, P. Tan, X.D. Tu, L.G. Zhang
    HUST, Wuhan, People’s Republic of China
 
  Range shifter plays a key role in decreasing the energy of the proton beam to realize shallow tumours treatment with the scanning nozzle in Huazhong University of Science and Technology Proton Therapy Facility (HUST-PTF). To control the transverse scattering and decrease the damage to healthy tissue caused by secondary particle, influence of the range shifter material was studied. In this paper, the Monte Carlo software Geant4 and FLUKA are applied to analyse the transport process of proton beam in the range shifters made of six different materials: PMMA, Lexan, Lucite, Polyethylene, Polystyrene, and Wax. The beam spot sizes at the iso-center with or without range shifter was calculated for the HUST-PTF scanning nozzle. The relationship between the thickness of the range shifters of the six materials and the proton energy was obtained. The secondary neutron yield at the end of the nozzle was also analysed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB118  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPTS037 The Deformation-Stress Simulation and Measurement of Titanium Foil Strip for Hadron Monitor electron, simulation, experiment, hadron 4187
 
  • A.X. Wang, J.X. Chen, H.Y. He, L. Liu, X.J. Nie, C.J. Ning, J.L. Sun, G.Y. Wang, J.B. Yu, Y.J. Yu, J.S. Zhang, D.H. Zhu
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • L. Kang
    IHEP, Beijing, People’s Republic of China
 
  The measurement of beam profile by hadron monitor is in fact the measurement of the positive current after the secondary electrons escaped. According to the situation that the number of beam particles is small and the current signal is weak, the material titanium with high secondary electron generation rate is select by material comparison, and the foil strip type is used to increase the cross section area to obtain lager current level. On account of dead weight itself, as well as thermal expansion and contraction, the foil strip shall be loose. The loosen strip will deviate from its theoretical position, and cause the measuring error. Therefore, the deformation-stress of Ti foil strip (1000*50*0.1) was simulated under the pretension (10~90N) with the finite element software ANSYS. A set of experiment device with pretension adjustment and heating for the foil strip was designed, and then the deformation-stress was tested by a high precision 3-D imaging measurement system. Compared with the simulation results, the pretension would better set at about 50N.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS037  
About • paper received ※ 12 May 2019       paper accepted ※ 19 May 2019       issue date ※ 21 June 2019  
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THPTS045 Preparation of Titanum-Zirconium-Vanadium Films by Quantitative Deposition vacuum, experiment, electron, operation 4210
 
  • J.Q. Shao, C. Chen, X.Q. Ge, W. Li, S. Wang, Y. Wang, W. Wei, B. Zhang, Y.X. Zhang, B.L. Zhu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  TiZrV has been used in vacuum technology and electric vacuum devices due to its high pumping speed and low activation temperature in recent years. At the same time, many preparation methods have been developed. Different from the current coating method of magnetron sputtering, this paper discusses the preparation of thin film coating from the viewpoint of vacuum sintering, which is flexible in design and more suitable for operation. Based on the analysis of the surface morphology of the sintered film, the feasibility and operability of the experimental method were explored from the surface compactness of the getter.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS045  
About • paper received ※ 25 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPTS048 Design of Longitudinal Gradient Bending Magnet of HALS multipole, permanent-magnet, synchrotron, lattice 4215
 
  • B. Zhang, C. Chen, Z.L. Ren, X.Q. Wang, H. Xu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  Hefei Advanced Light Source (HALS) is a diffraction limited light source, which was proposed and expected to be built in the next few years by National Synchrotron Radiation Laboratory (NSRL) of China. Just like other new light sources, longitudinal gradient bending magnet (LGB) will be adopted to suppress the beam emittance. The magnet consists of 7 modules with different magnet-ic field. Each module has yoke and poles with the same size but different amount of permanent magnet to gener-ate field gradient. FeNi alloy is used to shunt magnetic flux and thus improve the temperature stability. Correc-tor coil or movable wedge can be used to adjust the field. Impact of magnetization direction error of permanent magnet block and parallelism error of poles on multi-poles is also evaluated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS048  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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