Keyword: quadrupole
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MOPO028 Survey and Alignment System of 100 MeV/100 kW Electron Linear Accelerator target, survey, electron, neutron 87
 
  • O. Bezditko, I.I. Karnaukhov, A.Y. Zelinsky
    NSC/KIPT, Kharkov, Ukraine
 
  For successful operation and working of electron linear accelerator of "NEUTRON SOURCE" driver it is necessary that all the acceleration sections, the quadrupole triplets, the quadrupole lenses, the dipole magnets, the scanning magnets and the chicane should be installed in design position according design parameters. Accuracies of all electromagnetic elements installation are 150 mkm for all three rotation freedom. The whole process, fiducialization and developing of survey net, alignment is controlled by laser tracker Leica AT 401.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO028  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO087 Cold Test of Hybrid RFQ Prototype rfq, cavity, simulation, DTL 184
 
  • P.Y. Yu, Y. He, C.X. Li, F.F. Wang, Z.J. Wang, B. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
 
  Hybrid RFQ is proposed as a potential good choice at the low-energy range of linear accelerator, which is combined by four-vane RFQ structure and CH-DTL structure. It has higher energy gain rate compared to conventional RFQ, and it is more compact than traditional DTL. In order to research on process exploration and RF parameters of this structure, an aluminium prototype is developed. The cold test of Hybrid RFQ prototype is completed. This paper will present the results and analysis of the test.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO087  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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MOPO096 Realistic Modeling of MEBT for the New LANSCE RFQ Injector DTL, emittance, rfq, proton 211
 
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
 
  The new RFQ-based proton injector at LANSCE requires a specialized medium-energy beam transfer (MEBT) after the RFQ at 750 keV due to a following long (~3 m) existing common transfer line that also transports H beams to the DTL entrance. The horizontal space for MEBT elements is limited because two beam lines merge at 18-degree angle. The MEBT includes two compact quarter-wave RF bunchers and four short quadrupoles with steerers, all within the length of about 1 m. The beam size in the MEBT is large, comparable to the beam-pipe aperture, hence non-linear 3D fields at large radii and field-overlap effects become important. With CST Studio codes, we calculate buncher RF fields and quadrupole and steerer magnetic fields, and use them for particle-in-cell beam dynamics modeling of MEBT with realistic beam distributions from the RFQ. Our results indicate significant emittance growth in MEBT not predicted by the standard beam dynamics codes. Its origin is traced mainly to the quadrupole edge fields; the buncher RF fields also contribute noticeably. Proposed design modifications improve the MEBT performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO096  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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MOPO116 Study on the Control Technology of Large-load Time Constant Accelerator Magnet Power Supply controls, power-supply, collider, simulation 239
 
  • X. Wang, F. Long
    IHEP, Beijing, People’s Republic of China
 
  With the increasing application of power supply to industrial system, digital control system has become the mainstream of modern industrial control system. The wide application of digital control system has also led to the rapid development of digital controller. In the field of accelerator magnet power supply, the adoption of digital closed-loop control has become a trend in recent years. Due to the system’s tracking and regulation characteristics, the output current will slowly track the change of the given value in the course of the given current gradually rising. When the system reaches steady state, the disturbance of the system requires the regulator to adjust at a faster rate to correct the impact of the disturbance on the system. Today’s digital power supply control method mainly reflected in when load time constant is large, interference or load change, the power output is prone to overshoot or adjust the time is long, so the tracking and adjustment features cannot be met simultaneously. Therefore, this paper will study the power supply digital control technology for large - load time constant and the independent control method of tracking and regulating.  
poster icon Poster MOPO116 [0.307 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO116  
About • paper received ※ 21 August 2018      issue date ※ 18 January 2019  
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TU2A03 Layout of the New FAIR Post-stripper DTL for Intense Heavy Ion Beams DTL, cavity, operation, emittance 303
 
  • S. Mickat, X. Du, P. Gerhard, L. Groening, M. Heilmann, M. Kaiser, A. Rubin, V. Srinivasan, W. Sturm
    GSI, Darmstadt, Germany
 
  The new post-stripper DTL at GSI shall accelerate uranium beams with space charge induced tune depressions of up to 37% to 11.4 MeV/u. Emittance dilution must be kept below few percent. However, the layout must also allow for delivery of lightest ions to just 3.0 MeV/u. This broad-banded range of requirements imposes huge challenges on the layout and fabrication especially of the cavities and drift tube magnets.  
slides icon Slides TU2A03 [4.777 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU2A03  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO004 RF Design and Cold Model Measurement of an IH-DTL for HIMM Injector DTL, cavity, linac, simulation 329
 
  • H. Du, Q.Y. Kong, Z.S. Li, K.D. Wang, X. Yin
    IMP/CAS, Lanzhou, People’s Republic of China
 
  An interdigital H-mode drift tube linac (IH-DTL) will be constructed as a postinjector linac for the Heavy Ion Medical Machine (HIMM). Its resonant frequency, injec-tion and final energies are determined from beam dynamics and hardware parameters considerations of the entire machine to be 162.5MHz, 600keV/u and 4MeV/u, respectively. The beam duty cycle of the injector linac is less than 0.1% based on the injection requirements of the synchrotron. Beam dynamics and RF structure design and optimize of the IH-DTL has been finished. The maximum surface electric field is less than 2.0-times the Kilpatric limit for accelerating C4+ beam. This IH-DTL contains 42 accelerating gaps and two focusing quadrupole triplets. In order to examine the field distribution of the IH-DTL which reaches the length of 3.17m, an aluminum alloy 1:1 cold model cavity with 4 moveable tuners and 2 empty focusing magnet shell was constructed. The relative intertube-distance errors are less than ±50μm. The measurements show that the gap voltage values can match the CST-MWS simulating results within relative difference of ±3% by adjusting the 4 moveable tuners.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO004  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO085 Modelling of Beam Parameters of RF Linac for GBS-ELI-NP linac, simulation, gun, cathode 528
 
  • P.S. Tracz
    IFIN-HH, Bucharest - Magurele, Romania
 
  The Gamma Beam System at the ELI-NP (Extreme Light Infrastructure - Nuclear Physics) currently being constructed in Magurele/Bucharest, Romania will be a high-brilliance advanced source of gamma rays based on laser Compton back-scattering. For a successful operation of the GBS a high brightness low emittance electron beam is of crucial importance. The warm RF linac is designed in two stages - one with the beam up to 300 MeV, and another one about 720 MeV. The S-band photo-injector is combined with a C-band linac. The beam is transported by transfer lines to the interaction points. In this paper we report the results of computer simulations of the electron beam transport in the low energy linac and transfer line up to the low energy interaction point (IP1). The simulation model makes it possible to predict the beam parameters to be recuperated in case of failure of any magnetic or accelerating elements as well as it enables to determine the optimal parameters of replaced components. It will be used for the development of the Gamma Beam System in the future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO085  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO114 Beam Dynamics Studies for the CSNS DTL Due to a Quadrupole Fault lattice, DTL, linac, MMI 573
 
  • J. Peng, M.T. Li, Y.D. Liu, X.H. Lu, X.B. Luo
    CSNS, Guangdong Province, People’s Republic of China
  • Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, S. Wang, S.Y. Xu, Y. Yuan
    IHEP, Beijing, People’s Republic of China
 
  The China Spallation Neutron Source(CSNS) accelera-tor systems is designed to deliver a 1.6GeV, 100kW pro-ton beam to a solid metal target for neutron scattering research. It consists of a 50keV H Ion Source, a 3MeV Radio Frequency Quadrupole (RFQ), an 80MeV Drift Tube Linac (DTL), and a 1.6GeV Rapid-cycling Synchro-tron (RCS). The DTL consists of four tanks. In 2017, three of four tanks have been commissioned successfully, and beam has been accelerated to 61MeV with nearly 100% transmission. However, in July 2017, one quadrupole contained in the drift tube was found fault, the beam transmission decreased to 80%. A new lattice has been designed and the 100% transmission has recovered. In January 2018, the last tank of the DTL has been commissioned and accelerated the H beam to the design energy of 80MeV for the first time. The commissioning progress and the measurement results before and after lattice adjustment will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO114  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO116 Particle Dynamics Optimization in DTL cavity, focusing, DTL, emittance 579
 
  • I. Skudnova
    Saint Petersburg State University, Saint Petersburg, Russia
 
  The research concerns ion dynamics in linear accelerators with drift tubes (DTL). Permanent quadrupole magnets are placed inside some of the drift tubes. Frequency of the field is 432 MHz. Electromagnetic fields and particle dynamics in the cavity are calculated using Comsol Multiphysics software. The input energy of the beam is 6 MeV, output 10 MeV. Initial beam is assumed to come from Radio Frequency Quadrupole accelerator (RFQ). The considered parameters are drift tubes radii, cavity diameter, gradient of the magnetic field from quadrupoles inside drift tubes and focusing lattice. Effectiveness is estimated by the emittance growth.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO116  
About • paper received ※ 14 September 2018      issue date ※ 18 January 2019  
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THPO028 Magnetic Field Measurement and Analysis for Drift Tube Linac of CSNS DTL, cavity, drift-tube-linac, linac 738
 
  • B. Li, M.X. Fan, A.H. Li, P.H. Qu, Y. Wang, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  • Q. Chen, K.Y. Gong, W. Kang, H.C. Liu, J.X. Zhou
    IHEP, Beijing, People’s Republic of China
 
  Funding: The National Natural Science Foundation of China(11105166); Youth Innovation Promotion Association(2015011)
A 324MHz Alvarez-type Drift Tube Linac (DTL) is used to accelerate the H ion beam from 3 to 80 MeV with peak current 15mA for China Spallation Neutron Source (CSNS). DTL is composed by 36 meters cavity and 161 DTs, the DT magnet coil adopted SAKAE structure with compact, smaller aperture. Magnetic field is measured by self-developed high precision rotating coil measurement system. This paper introduces the rotating coil measure-ment system simply and presents the 161 DTs magnetic field measurement results comprehensively, include mag-netic field center offset, integral magnetic field, higher-order harmonics. In addition, cooling test result of magnet coil is also presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO028  
About • paper received ※ 31 August 2018      issue date ※ 18 January 2019  
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THPO033 The Development of Permanent Magnet Quadrupoles for Xipaf DTL multipole, DTL, permanent-magnet, radiation 753
 
  • B.C. Wang, M.T. Qiu, Z.M. Wang, C.Y. Wei
    NINT, Shannxi, People’s Republic of China
  • C.T. Du, Q.K. Guo, X.W. Wang, Q.Z. Xing, S.X. Zheng
    TUB, Beijing, People’s Republic of China
 
  Permanent magnet quadrupoles (PMQs) are developed for the DTL of Xi’an 200 MeV Proton Application Facility (XiPAF). In this paper, we describe the fabrication and measurements for the Halbach-type PMQs. The main procedure of the PMQ manufacture is presented. And the magnetic measurements of PMQs are carried out with the help of vibrating wire, Hall probe and rotating coil respectively. The results show the PMQs are able to meet the requirements of XiPAF DTL.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO033  
About • paper received ※ 10 September 2018      issue date ※ 18 January 2019  
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THPO052 High Power Test of the LEAF-RFQ rfq, acceleration, cavity, operation 808
 
  • L. Lu, Y. He, W. Ma, L.B. Shi, L.T. Sun, L.P. Sun, L. Yang, Y. Yang, H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
 
  High power heavy ion drivers require a CW low-frequency accelerator for initial acceleration. A CW four-vane radio frequency quadrupole (RFQ) accelerator is designed to accelerate heavy ions A/q up to 7 from 14 keV/u to 500 keV/u, as a new injector for the Low Energy Accelerator Facility (LEAF) at Institute of Modern Physics (IMP). The measurements of low power test were reported previously. In this paper, the results of high power test of the RFQ, including the test of the acceleration systems and beam profiles, will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO052  
About • paper received ※ 07 September 2018      issue date ※ 18 January 2019  
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THPO064 Tuning of a Four-vane RFQ for Xi’an 200 MeV Proton Application Facility rfq, dipole, cavity, coupling 838
 
  • X.D. Yu, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, X.W. Wang, Q.Z. Xing, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  • B.C. Wang, Z.M. Wang, C. Zhao
    NINT, Shannxi, People’s Republic of China
 
  This paper mainly describes the procedures and results of tuning a four-vane Radio Frequency Quadrupole (RFQ) accelerator for the Xi’an 200 MeV Proton Application Facility (XiPAF) project. The 3-meter-long RFQ will accelerate a 50 keV H beam from the ECR source to 3 MeV, and deliver it to the downstream drift tube linac (DTL) with a peak current of 5 mA, pulse length of 10-40 μs and maximum repetition rate of 0.5. The machining, assembly, and RF tuning of the RFQ cavity has been completed successfully. After tuning, the relative error of the operating quadrupole mode field is within ±2.7%, and the dipole mode com-ponent is within ±1.9% of the quadrupole mode. The RFQ now is ready for high-power RF conditioning.  
poster icon Poster THPO064 [1.413 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO064  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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THPO118 Beam Transverse Coupling and 4D Emittance Measurement Simulation Studies for PITZ emittance, coupling, simulation, gun 945
 
  • Q.T. Zhao, M. Krasilnikov, H.J. Qian, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • Q.T. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
 
  The Photo Injector Test Facility at DESY, Zeuthen site (PITZ) was built to test and optimize high brightness electron sources for Free Electron Lasers (FELs) like FLASH and the European XFEL. Although the beam emittance has been optimized and experimentally demonstrated to meet the requirements of FLASH and XFEL, transverse beam asymmetries were observed during operation of the RF guns. Based on previous studies [1], the beam asymmetries most probably stem from beam transverse coupling by quadrupole field errors in the gun section. A pair of normal and skew gun quadrupoles was successfully used for reducing the beam asymmetries in experiment. In this paper, we discuss the beam transverse coupling between X and Y planes due to quadrupole field errors and its impact onto horizontal and vertical rms emittance. Multi-quads scan and two quads with rotated slits scan were proposed to measure the 4D beam matrix for PITZ and tested by simulation, which will give the residual beam coupling after gun quadrupoles compensation and would be helpful for minimizing the 2D rms emittance experimentally.  
poster icon Poster THPO118 [1.521 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO118  
About • paper received ※ 08 September 2018      issue date ※ 18 January 2019  
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FR1A01 Results From the 6D Diagnostics Test Bench at SNS simulation, experiment, diagnostics, emittance 966
 
  • B.L. Cathey
    ORNL RAD, Oak Ridge, Tennessee, USA
  • A.V. Aleksandrov, S.M. Cousineau, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This work has been partially supported by NSF Accelerator Science grant 1535312.
This paper presents the method and results for measuring the full six-dimensional phase space of a low energy, high intensity hadron beam. This was done by combining four-dimensional emittance measurement techniques along with dispersion measurement and a beam shape monitor to provide the energy and arrival time components. The measurements were performed on the new Beam Test Facility (BTF) at the Spallation Neutron Source (SNS), a 2.5 MeV functional duplicate of the SNS accelerator front end. The results include a correlation the had not previously been observed.
 
slides icon Slides FR1A01 [7.083 MB]  
poster icon Poster FR1A01 [1.742 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-FR1A01  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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