Keyword: injection
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TUPO070 Design and Commissioning of KEK New Vacuum Furnace for SRF Cavity Development cavity, vacuum, MMI, SRF 496
 
  • K. Umemori, M. Egi, E. Kako, T. Konomi, S. Michizono, H. Sakai
    KEK, Ibaraki, Japan
 
  Recently new techniques such as Nitrogen-doping and Nitrogen-infusion have been developed to improve performance of SRF (Superconducting RF) cavities. We purchased a new vacuum furnace, which is key to realize these techniques. Cleanness of the furnace is most important issue. The furnace has a cryo-pump and whole of vacuum system is oil-free system. Target vacuum level after cooling down is 1x10-6 Pa. Heater, reflectors and support table were made from Molybdenum to avoid contamination during heat treatment. Metal gaskets are used for all vacuum seals, except big doors. Maximum operation temperature is 1150 degree C. Size is around 1 m diameter and 2m long for a 1.3 GHz 9-cell cavity. Entrance of furnace is covered by a clean booth. The furnace was fabricated, assembled at KEK COI building and commissioned this year. After several burning runs, target vacuum pressure was achieved after cooling down to room temperature. Design of the furnace and performance during commissioning runs are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO070  
About • paper received ※ 19 September 2018      issue date ※ 18 January 2019  
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TUPO071 Study on Nitrogen Infusion for 1.3 GHz SRF Cavities Using J-PARC Furnace cavity, SRF, background, vacuum 499
 
  • K. Umemori, T. Dohmae, M. Egi, Y. Hori, E. Kako, T. Konomi, S. Michizono, T. Saeki, H. Sakai, Y. Yamamoto
    KEK, Ibaraki, Japan
  • J. Kamiya
    JAEA/J-PARC, Tokai-mura, Japan
  • S. Kurosawa, K. Takeishi
    JAEA, Ibaraki-ken, Japan
  • T. Okada
    Sokendai, Ibaraki, Japan
 
  Nitrogen infusion (N-infusion) is new surface treatment technique for niobium SRF (Superconducting RF) cavities. After cooling down from 800 degree C heat treatment, a vacuum furnace and cavities are kept 120 degree C, 48 hours with about 3 Pa Nitrogen. Improvement of Q-value and accelerating gradient is expected. We used J-PARC furnace, since N-infusion procedure requires clean vacuum furnace. It has a cryo-pump and turbo molecular pumps and its vacuum system is oil-free system. Six times of N-infusion tests were carried out, while changing vacuum condition, N-infusion temperature, Nitrogen pressure, niobium material and so on. Niobium caps were mounted on cavities to avoid contaminations on inner surfaces. Some of trials were successful and vertical test results showed improvement of Q-values and accelerating gradient. However, some of them were not. Most of bad cases showed degradation of Q-values above 5 MV/m. Details of heat treatment procedure including N-infusion and vertical test results are shown in this presentation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO071  
About • paper received ※ 20 September 2018      issue date ※ 18 January 2019  
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TUPO073 Niobium Sample Analysis for Nitrogen Infusion and Doping cavity, niobium, vacuum, ECR 506
 
  • T. Konomi, E. Kako, S. Michizono, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
  • T. Nagata
    ULVAC, Inc., Tsukuba, Japan
  • T. Nojima
    Tohoku University, Sendai, Japan
 
  KEK has been investigating the better conditions of the heat treatment in nitrogen, which are called as nitrogen doping and nitrogen infusion. We have tried to understand the high gradient performance of the cavity from the analyses of samples which were prepared in the same conditions for the cavity. The main tools are D-SIMS for the depth profile of the elemental concentration, XPS for composition analysis and SQUID magnetometry for the critical DC magnetic field measurement. The difference in the depth profiles of the nitrogen, carbon and oxygen between the heat treatment conditions was observed in vacuum and furnace temperature of nitrogen infusion by D-SIMS and XPS. Such a difference correlates with the vortex penetration field measured by SQUID. In particular, that of nitrogen doping sample was greatly degraded, while that of nitrogen infusion sample was slightly improved. The tendency is similar to the RF high gradient test results. Details of the sample analysis are shown in this presentation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO073  
About • paper received ※ 18 September 2018      issue date ※ 18 January 2019  
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TUPO101 Design of Practical HSC Type Injector for Cancer Therapy rfq, linac, DTL, cavity 557
 
  • C.C. Xing, T. He, C.X. Li, J. Li, L. Lu, L. Yang
    IMP/CAS, Lanzhou, People’s Republic of China
 
  The Hybrid single cavity(HSC), which is designed for 20 mA beam acceleration, is a new HSC Type Injector for Cancer Therapy. Its designed particle, resonant frequency, injection and final energies are designed from beam-optics considerations of the entire system to be C6+, 100MHz, 20keV/u and 0.6MeV/u. In order to achieve these requirements, keeping the Maximum surface electric field to less than 1.9-times the Kilpatrick limit, the RFQ becomes about 1.2 m long and the DTL is about 2.5 m long. The total efficiency of transmission is more than 80%.  
poster icon Poster TUPO101 [0.345 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO101  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO115 Beam Parameters Measurement and Correction in CSNS Linac linac, emittance, MMI, DTL 576
 
  • Z.P. Li, Y. Li
    IHEP, Beijing, People’s Republic of China
  • J. Peng
    CSNS, Guangdong Province, People’s Republic of China
 
  All the beam parameters of China Spallation Neutron Source (CSNS) linac had achieved the acceptance goals in January 2018 after a 2-year commissioning. Parameters of the H beam were carefully studied and corrected. Beam energy was measured and the energy dispersion are reduced. Transverse emittance are obtained by different tools and methods. Linear optics measurements and corrections were carried out under varied beam energies and peak intensities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO115  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TH1P01 Commissioning of CERN LINAC4 linac, MMI, proton, emittance 658
 
  • A.M. Lombardi
    CERN, Geneva, Switzerland
 
  This talk reviews the commissioning effort of CERN’s new H linear accelerator, Linac4, which is presently undergoing a beam quality and reliability run. Linac4 will be connected to the LHC proton injector chain during the next long LHC shutdown (LS2) and will then replace the 50MeV proton Linac2.  
slides icon Slides TH1P01 [4.591 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TH1P01  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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THPO001 Design Study on CEPC Positron Damping Ring System damping, linac, positron, emittance 672
 
  • D. Wang, Y.L. Chi, J. Gao, D.J. Gong, C. Meng, G. Pei, J.R. Zhang
    IHEP, Beijing, People’s Republic of China
 
  The primary purpose of CEPC damping ring is to reduce the transverse phase spaces of positron beam to suitably small value at the beginning of linac and hence reduce the beam loss in the booster. Before damping ring, an energy spread compression structure is designed to match the RF acceptance of damping ring. A longitudinal bunch length control is also necessary to meet the energy spread requirement in the linac by a bunch compressor system after the damping ring. Both designs for damping ring and energy/bunch compressors are discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO001  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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THPO004 Pulsed Operation of CEBAF for JLEIC Injection cavity, electron, beam-loading, linac 682
 
  • J. Guo, J.M. Grames, R. Kazimi, F. Lin, T. E. Plawski, R.A. Rimmer, H. Wang
    JLab, Newport News, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
JLab Electron Ion Collider (JLEIC) is planning to use the recently upgraded 12 GeV CEBAF 1497 MHz SRF CW recirculating linac as a full-energy injector for the electron collider ring. The JLEIC electron injection requires 3-4µs long bunch trains with a 20-400ms spacing in between, resulting in uneven beam loading for the CW CEBAF. With the high beam current in JLEIC collider rings, the low duty factor of injection also requires to a very high pulsed beam current from CEBAF, exacerbating the transient beam loading issue. In this paper, we will present CEBAFs detailed pulsed operation scheme for JLEIC injection, as well as some experimental results at CEBAF.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO004  
About • paper received ※ 20 September 2018      issue date ※ 18 January 2019  
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THPO017 Progress of the Novel Three-dimensional Spiral Injection Scheme Test Experiment kicker, site, electron, experiment 717
 
  • M.R. Rehman
    Sokendai, Ibaraki, Japan
  • K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa
    KEK, Ibaraki, Japan
  • H. Iinuma
    Ibaraki University, Hitachi, Ibaraki, Japan
 
  Funding: This work was supported by JSPS KAKENHI Grant Number JP26287055 and JP 23740216.
A new muon g-2/EDM experiment at J-PARC (E34) is under preparation in order to resolve a 3𝜎 discrepancy of muon anomalous magnetic dipole moment between the measurement and the standard model prediction. The E34 experiment will employ a unique three-dimensional spiral injection scheme in order to store the muon beam into a small storage orbit. In order to demonstrate the feasibility of this novel injection scheme, the Spiral Injection Test Experiment (SITE) with the electron beam is under construction at KEK Tsukuba campus. The goals of the SITE are divided into two phases. In the first phase of the SITE, 80 keV DC electron beam was injected and detected as a fluorescent light due to the de- excitation of the nitrogen gas into solenoidal storage magnet. In the second phase of the SITE, the pulsed electron beam, and a pulsed magnetic kicker are developed in order to keep the pulsed beam on the very midplane of the solenoidal storage magnet. This paper describes the achievements of the first phase of SITE and progress towards the second phase.
*H. Iinuma et al., Nuclear Instruments and Methos in Physics Research A, 832, 51-62 (2016).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO017  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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THPO061 Beam Characterization of the MYRRHA-RFQ rfq, diagnostics, proton, simulation 830
 
  • P.P. Schneider, M. Droba, O. Meusel, H. Podlech, A. Schempp
    IAP, Frankfurt am Main, Germany
  • D. Noll
    CERN, Geneva, Switzerland
 
  Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) #05P15RFRBA and HORIZON 2020 for the MYRRHA project #662186 and HIC for FAIR.
The Linear Accelerator for the MYRRHA project* is under construction. In a first step the linac up to 100 MeV will be realized. The LEBT section has been set into operation in Belgium and the RFQ is installed in summer 2018. A system to analyze the ion beam consisting of a slit-grid emittance scanner, a beam dump and a momentum spectrometer, called diagnostic train descripted in **, will be set on the rails to characterize the beam at the RFQ injection point. The results will be used to adjust the optimal matching for the RFQ. After the measurements downstream the LEBT, the diagnostic train begins its journey along the beam line and at the first station the RFQ is installed. The accelerated beam of the RFQ is then analyzed and optimized. In addition to optimization of transmission the artificial production of beam offsets in the LEBT is of special interest. These will be measured at the injection point to estimate the range of possible offsets. In the following measurements these offsets will be used to study the influence of the offsets on the RFQ performance. Furthermore, the RFQ parameters are varied to see their influence on the beam transport, transmission and beam quality.
* H.Aı̈t Abderrahim et al. "MYRRHA: A multipurpose accelerator driven system for research & development", 2001
** 1st Experiments at the CW-Operated RFQ for Intense Proton Beams, LINAC16
 
poster icon Poster THPO061 [4.610 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO061  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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FR1A05 Development of Pulsed Gas Strippers for Intense Beams of Heavy and Intermediate Mass Ions target, heavy-ion, operation, linac 982
 
  • P. Gerhard, W.A. Barth, M. Bevcic, Ch.E. Düllmann, L. Groening, K.P. Horn, E. Jäger, J. Khuyagbaatar, J. Krier, M.T. Maier, P. Scharrer, A. Yakushev
    GSI, Darmstadt, Germany
  • W.A. Barth, Ch.E. Düllmann, J. Khuyagbaatar
    HIM, Mainz, Germany
  • Ch.E. Düllmann
    Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany
 
  The GSI UNILAC together with SIS18 will serve as injector for the future FAIR. A modified 1.4~MeV/u gas stripper setup has been developed, aiming at an increased yield into the particular desired charge state. The setup delivers short pulses of high gas density in synchronization with the beam pulse. This provides a higher gas density. Different gases as stripping targets were tested. Measurements with various isotopes and gas densities were conducted to investigate the stripping properties. High intensity beams of 238U4+ were successfully stripped using hydrogen as stripping gas. The stripping efficiency was significantly increased while the beam quality remained suitable. The new stripper setup and major results achieved during the development are presented. Problems with the fast valves arose while they were used for a longer duration. Another revision of the setup took place to exchange the valves. In parallel, the installation of the required infrastructure for regular operation of the gas stripper using hydrogen was planned.  
slides icon Slides FR1A05 [10.013 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A05  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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