MC4: Hadron Accelerators
A14 Neutron Spallation Facilities
Paper Title Page
MOPAB198 Study on Magnet Sorting of the CSNS/RCS Dipoles 665
 
  • Y. Li, Y.W. An
    IHEP, Beijing, People’s Republic of China
  • Z.P. Li, S.Y. Xu
    DNSC, Dongguan, People’s Republic of China
 
  The 1.6GeV rapid cycling synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high-power pulsed proton machine aiming for 500kW output beam power. Now, the routine output beam power has been increased to 100kW. However, the horizontal bare orbit in the ring is large (15mm) and the number of correctors is small, which brings great challenges to the ramp-up of beam power. It is found that the bare orbit in AC mode is 3-4mm larger than that in DC mode. The reason is that the AC dipoles field error is larger than DC dipoles field error. Therefore, it is proposed to sort dipoles again according to the AC dipoles field error. In order to reduce the risk of beam commissioning, fewer magnets should to be moved to achieve smaller orbit. The best results of moving two to six magnets were calculated. After sorting, the orbit can be reduced by 3-4mm, which reduces the difficulty of orbit correction.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB198  
About • paper received ※ 16 May 2021       paper accepted ※ 21 May 2021       issue date ※ 14 August 2021  
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MOPAB200 Parameters Measurements of Proton Beam Extracted from CSNS/RCS 668
 
  • Z.P. Li, Y.W. An, M.Y. Huang
    IHEP, Beijing, People’s Republic of China
  • Y. Li, S.Y. Xu
    DNSC, Dongguan, People’s Republic of China
  • H.Y. Liu
    IHEP CSNS, Guangdong Province, People’s Republic of China
 
  In order to study the emittance evolution of the circulating beam in the fast-cycling synchrotron (RCS) of the Chinese Spallation Neutron Source (CSNS), parameter measurements of the beam extracted at different times were carried out. The measurements were mainly based on wire-scanners mounted in RCS to target transport line (RTBT) for beam profile measurement, and different methods were applied in the solution processes. The emittance and C.S parameters of the extracted beam at different times were obtained and studied, which provided an important reference basis for the beam commissioning of RCS. The beam envelope along the RTBT has been matched and re-measured, which was in good agreement with the design optics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB200  
About • paper received ※ 19 May 2021       paper accepted ※ 21 May 2021       issue date ※ 25 August 2021  
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TUPAB176 ESS Proton Beam Trajectory Correction 1809
 
  • N. Blaskovic Kraljevic, M. Eshraqi, N. Milas, R. Miyamoto
    ESS, Lund, Sweden
 
  The proton linac of the European Spallation Source (ESS) is under construction in Lund, Sweden. Beam trajectory correction is essential to mitigate the effect of accelerator element misalignment, constituting the first step to minimise beam losses. The correction will be performed using correctors distributed along the accelerator, based on the beam position monitor (BPM) readout. Three trajectory correction techniques are considered: one-to-one steering, Singular Value Decomposition (SVD), and MICADO (selecting a subset of correctors for the trajectory correction). The performance of the three methods is simulated for the ESS linac and a comparison of the outcomes is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB176  
About • paper received ※ 19 May 2021       paper accepted ※ 15 June 2021       issue date ※ 27 August 2021  
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TUPAB192 Studies on Momentum Collimation for CSNS-RCS Upgrades 1855
 
  • Y.W. An, J. Chen, S.Y. Xu, Y. Yuan
    IHEP, Beijing, People’s Republic of China
  • X.H. Lu, J.B. Yu
    IHEP CSNS, Guangdong Province, People’s Republic of China
 
  The CSNS project was a high intensity pulsed facility, and achieved the the design goal of 100kW in 2020. The upgrades of the CSNS are proposed, and the momentum collimator is a component of the upgrades. This paper will show the design scheme of the momentum collimator and the simulation results are also presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB192  
About • paper received ※ 18 May 2021       paper accepted ※ 15 June 2021       issue date ※ 28 August 2021  
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TUPAB195 Local Orbit Correction Application for CSNS-RCS High Intensity Commissioning 1865
 
  • Y.W. An, Y. Li, S.Y. Xu, Y. Yuan
    IHEP, Beijing, People’s Republic of China
  • M.T. Li
    IHEP CSNS, Guangdong Province, People’s Republic of China
 
  The China Spallation Neutron Source (CSNS) is a high intensity hadron pulse facility which achieved the design goal in March, 2020. The Rapid Cycling Synchrotron (RCS) is the important part of the CSNS which accelerates the proton beam from 80MeV to 1.6GeV. During the high intensity commissioning of the RCS, an local orbit correction application was developed. Because of the good performance of the local orbit controlling at the ramping stage, the beam loss was optimized effectively in the process of the acceleration. In the paper, the efficiency of the beam loss optimization during the acceleration is given and the future plans were proposed.  
poster icon Poster TUPAB195 [2.279 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB195  
About • paper received ※ 13 May 2021       paper accepted ※ 17 June 2021       issue date ※ 01 September 2021  
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TUPAB198 ESS DTL Tuning Using Machine Learning Methods 1872
 
  • J.S. Lundquist, N. Milas, E. Nilsson
    ESS, Lund, Sweden
  • S. Werin
    Lund University, Lund, Sweden
 
  The European Spallation Source, currently under construction in Lund, Sweden, will be the world’s most powerful neutron source. It is driven by a proton linac with a current of 62.5 mA, 2.86 ms long pulses at 14 Hz. The final section of its normal-conducting front-end consists of a 39 m long drift tube linac (DTL) divided into five tanks, designed to accelerate the proton beam from 3.6 MeV to 90 MeV. The high beam current and power impose challenges to the design and tuning of the machine and the RF amplitude and phase have to be set within 1% and 1 degree of the design values. The usual method used to define the RF set-point is signature matching, which can be a time consuming and challenging process, and new techniques to meet the growing complexity of accelerator facilities are highly desirable. In this paper we study the usage of Machine Learning to determine the RF optimum amplitude and phase. The data from a simulated phase scan is fed into an artificial neural network in order to identify the needed changes to achieve the best tuning. Our test for the ESS DTL1 shows promising results, and further development of the method will be outlined.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB198  
About • paper received ※ 17 May 2021       paper accepted ※ 21 June 2021       issue date ※ 13 August 2021  
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TUPAB199 Progress on the Proton Power Upgrade at the Spallation Neutron Source 1876
 
  • M.S. Champion, C.N. Barbier, M.S. Connell, J. Galambos, M.P. Howell, S.-H. Kim, J.S. Moss, B.W. Riemer, K.S. White
    ORNL, Oak Ridge, Tennessee, USA
  • E. Daly
    JLab, Newport News, Virginia, USA
  • N.J. Evans, G.D. Johns
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science.
The Proton Power Upgrade Project at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory will double the proton power capability from 1.4 to 2.8 MW. This will be accomplished through an energy increase from 1.0 to 1.3 GeV and a beam current increase from 26 to 38 mA. The energy increase will be accomplished through the addition of 7 cryomodules to the linear accelerator (Linac). The beam current increase will be supported by upgrading several radio-frequency systems in the normal-conducting section of the Linac. Upgrades to the accumulator ring injection and extraction regions will accommodate the increase in beam energy. A new 2-MW-capable target and supporting systems will be developed and installed. Conventional facility upgrades include build-out of the existing klystron gallery and construction of a tunnel stub to facilitate future beam transport to the second target station. The project received approval to proceed with construction in October 2020. Procurements are in progress, and some installation activities have already occurred. Most of the installation will take place during three outages in 2022-2023. The project early finish is planned for 2025.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB199  
About • paper received ※ 10 May 2021       paper accepted ※ 28 May 2021       issue date ※ 21 August 2021  
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THPAB180 Simulation of 4D Emittance Measurement at the Spallation Neutron Source 4119
 
  • A.M. Hoover
    UTK, Knoxville, Tennessee, USA
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Similar to the KV distribution, the Danilov distribution has an elliptical shape and uniform density in the transverse plane and maintains these properties under any linear transport. Efforts are underway at the Spallation Neutron Source (SNS) to paint a Danilov distribution in the accumulator ring. After the beam has been painted, the level to which it approximates an ideal Danilov distribution must be quantified. One way to do this is to measure the four-dimensional emittance, which is ideally zero due to linear relationships between the phase space variables. To measure this emittance, we will utilize a standard method of reconstructing the covariance matrix using various optics settings in conjunction with beam profile measurements. We present the results of preliminary simulations which aim to optimize this measurement scheme for the SNS Ring to Target Beam Transport (RTBT) line.  
poster icon Poster THPAB180 [2.525 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB180  
About • paper received ※ 19 May 2021       paper accepted ※ 12 July 2021       issue date ※ 25 August 2021  
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