Author: Li, H.P.
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TUPAL050 Progress Work on a CW Deuteron RFQ with Magnetic Coupling Windows 1123
SUSPF054   use link to see paper's listing under its alternate paper code  
 
  • Q. Fu, M.J. Easton, P.P. Gan, S.L. Gao, H.P. Li, Y.R. Lu, Q.Y. Tan, Z. Wang, K. Zhu
    PKU, Beijing, People's Republic of China
  • W.P. Dou, Y. He
    IMP/CAS, Lanzhou, People's Republic of China
 
  Funding: This work was supported by the National Basic Research Program of China (Grant No. 2014CB845503).
A new 162.5 MHz RFQ has been built for a joint 973 project between Peking University (PKU) and Institute of Modern Physics (IMP). It is designed to deliver 50-mA deuteron beams to 1 MeV in CW mode, with an inter-voltage of 60 kV and a length of 1.809 m. Due to its window-type structure, the RFQ has compact cross-section, sufficient mode separation and high specific shunt impedance. It consists of two segments fabricated and installed at IMP. The assembling error of the cavity is less than 0.05 mm. The RF measurements show good electrical properties of the resonant cavity with a measured unloaded quality factor equal to 96.4% of the simulated value. After tuning, we obtained the nominal frequency and field unbalance within 1.0%. Preparation of high-power test of this RFQ is underway. This paper will cover the fabrication details and RF measurements, as well as the progress of high-power test.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL050  
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TUPAL051 Program for High-Intensity RFQ Design With Matched and Equipartitioned Design Strategy 1126
 
  • H.P. Li, M.J. Easton, Q. Fu, P.P. Gan, Y.R. Lu, Q.Y. Tan, Z. Wang, K. Zhu
    PKU, Beijing, People's Republic of China
 
  The deuteron driver accelerator of the Beijing Iso-tope Separation On-Line (BISOL) facility will acceler-ate and deliver a 20 mA deuteron beam to the targets with an energy of 40 MeV. As the injector of the driver linac, an RFQ is required to bunch and accelerate the 20 mA deuteron beam to 3 MeV with very high beam quality. In order to fulfil these requirements and re-duce time spent on optimization, an RFQ design pro-gram named RFQEP has been developed to generate the input file for the PARMTEQM code. In this program, the ‘matched and equipartitioned' design strategy is adopted to prevent halo formation and to avoid struc-ture resonances in high intensity RFQs. The detailed design aspects are studied in this paper and simulation results are given for an RFQ designed by this code, which shows the accuracy and the merits of the new program.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL051  
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TUPAL052 Multi-Physics Analysis of a CW IH-DTL for CIFNEF 1129
 
  • Q.Y. Tan, M.J. Easton, Q. Fu, P.P. Gan, H.P. Li, Y.R. Lu, Z. Wang
    PKU, Beijing, People's Republic of China
 
  The Compact Intense Fast NEutron Facility (CIFNEF) project aims to produce high intense neutrons via the 7Li (d, n) 8Be reaction using a 5 MeV, 10 mA deuteron linac. The main components of the linac are an ion source, a short radio frequency quadrupole (RFQ) and an interdigi-tal H-mode drift tube linac (IH-DTL). The IH-DTL will accelerate the continuous wave (CW) deuteron beam from 1 MeV to 5 MeV with a total cavity length of 1.25 m using Kombinierte Null Grad Struktur (KONUS) design, achieving an accelerating gradient of 3.2 MV/m. The RF power loss for the whole cavity is estimated to be 85 kW. This high power loss is a significant challenge to the cooling design, as it could cause large rises in tempera-ture, thermal deformation and frequency drift. A detailed multi-physics analysis of the CW IH-DTL is presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL052  
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THPAK075 Simulation of Particle Interactions in a High Intensity Radio-Frequency Quadrupole for Molecular Hydrogen Ions 3405
 
  • M.J. Easton, H.P. Li, Y.R. Lu, Z. Wang
    PKU, Beijing, People's Republic of China
  • J. Qiang
    LBNL, Berkeley, California, USA
 
  High-intensity deuteron accelerators run the risk of deuteron-deuteron interactions leading to activation. For this reason, in the commissioning phase, a molecular hydrogen ion (H2+) beam is often used as a model for the deuteron beam without the radiation risk. However, composite ions are susceptible to particle interactions that do not affect single ions, such as stripping of electrons and charge exchange. Such interactions affect the beam dynamics results, and may lead to production of secondary particles, which in high-intensity beams may cause damage to the accelerator and reduce the quality of the beam. In order to understand these effects, we have modified the IMPACT-T particle tracking code to include particle interactions during the tracking simulation through a high-intensity continuous-wave (CW) radio-frequency quadrupole (RFQ). This code is also designed to be easily extensible to other interactions, such as collisions or break-up of heavier ions. Preliminary results and possibilities for future development will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK075  
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THPAK076 Development and Benchmarking of the IMPACT-T Code 3408
SUSPF089   use link to see paper's listing under its alternate paper code  
 
  • H.P. Li, M.J. Easton, Y.R. Lu, Z. Wang
    PKU, Beijing, People's Republic of China
  • J. Qiang
    LBNL, Berkeley, California, USA
 
  The multi-particle tracking code IMPACT-T is widely used to calculate the particle motion in high intensity linacs. The code is a self-consistent three-dimensional beam dynamics simulation toolbox that utilizes the particle-in-cell method in the time domain. In the collaboration between PKU and LBNL, an RFQ module was implemented to the IMPACT-T code, which enables simulations of the accelerator front-end. In order to benchmark the newly developed module in the IMPACT-T code, we have simulated the beam transport in Beijing Isotope Separation On-Line (BISOL) high intensity deuteron driver linac. It consists of a 3 MeV RFQ and 40 MeV superconducting HWR linac with five cryomodules. After comparing the simulation results with PARMTEQM, TraceWin and Toutatis, we obtained a very good agreement, which represents the validation of the new code.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK076  
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THPAL070 Multi-Physics Analysis of Two Bunchers for CIFNEF 3815
 
  • Q.Y. Tan, M.J. Easton, Q. Fu, P.P. Gan, H.P. Li, Y.R. Lu, Z. Wang
    PKU, Beijing, People's Republic of China
 
  CIFNEF(Compact Intense Fast NEutron Facility) project will accelerate and deliver a 5 MeV deuteron beam to the targets to produce high-intense neutrons. A 2.5 MHz pulsed deuteron beam with bunch width within 2 ns is needed on the targets at last. To fulfill the special requirements of the beam dynamics, two types of bunchers are adopted in the CIFNEF. One is a 10.156 MHz buncher used in the low energy beam transport (LEBT) line to longitudinally focus the 50 keV deuteron beam to the RFQ longitudinal acceptance with 4 kV effective voltage. A lumped element model is adopted because of the low frequency and it consists of an inductance coil in parallel with the capacitance of drift tube. The other one is an 81.25 MHz buncher used in the high energy beam transport (HEBT) line to longitudinally focus the 5 MeV deuteron beam to 2 ns. A QWR cavity with 2-gaps is used to provide 150 kV effective voltage. Thermal and structural analyses have been carried out on these two bunchers. Details of simulations of these two bunchers are presented and discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL070  
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