IPAC2018 - List of Authors (Lu, Y.R.)

Paper	Title	Page
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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THPAL069	Simulation of a 10 mm Diameter Cascaded Plasma Window	3812
	P.P. Gan, S. Huang, Y.R. Lu, S.Z. Wang, K. Zhu PKU, Beijing, People's Republic of China
	As a windowless vacuum device, the 10 mm diameter 60 mm long plasma window designed by Peking University only achieved to separate 28.8 kPa from 360 Pa experimentally with 50 A direct current and 2.5 kW power. Based on our 10 mm diameter plasma window, we have proposed a cascaded plasma window to achieve the isolation of atmosphere and high vacuum. In this paper, a numerical 2D FLUENT-based magneto-hydrodynamic simulation on 10 mm diameter cascaded plasma window was developed. The gas inlet, arc creation and plasma expansion segments are all contained in this model. A set of parameters including pressure, temperature, velocity and current distribution were obtained and analysed. In our first simulation, the isolation of 100 kPa and 50 Pa pressure has been realised, and some interesting phenomena occurred.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL069
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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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THPAL071	Preliminary Emittance Measurement of Laser Driven Proton Beam Employing a Quadruple Triplet Magnet	3818
SUSPL089	use link to see paper's listing under its alternate paper code
	Wu,M.J. Wu, Y.X. Geng, Q. Liao, C. Lin, H.Y. Lu, Y.R. Lu, W.J. Ma, Y.R. Shou, X. Xu, X.Q. Yan, Y.Y. Zhao, J.G. Zhu, K. Zhu PKU, Beijing, People's Republic of China
	The Compact Laser Plasma Accelerator (CLAPA) has been built recently at Peking University, which composed of a 200TW laser acceleration platform and a beam line system. Proton with energy spread of <1%, up to 10 pC charge and different energies below 10 MeV have been produced and transported to the irradiation platform. Emittance is a critical parameter for beam transportation. The preliminary emittance measurement has been per-formed for CLAPA's proton beams using the quadrupole scan technique (QST). In the experiment, the focal spot size of the proton beam was changed by scanning the current of a quadrupole triplet magnet. The result shows that the normalized emittance is smaller than 0.01 mm·mrad for 5 MeV laser driven protons, which is on the same level of the previously reported work.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL071
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAL069

Simulation of a 10 mm Diameter Cascaded Plasma Window

3812

P.P. Gan, S. Huang, Y.R. Lu, S.Z. Wang, K. Zhu
PKU, Beijing, People's Republic of China

As a windowless vacuum device, the 10 mm diameter 60 mm long plasma window designed by Peking University only achieved to separate 28.8 kPa from 360 Pa experimentally with 50 A direct current and 2.5 kW power. Based on our 10 mm diameter plasma window, we have proposed a cascaded plasma window to achieve the isolation of atmosphere and high vacuum. In this paper, a numerical 2D FLUENT-based magneto-hydrodynamic simulation on 10 mm diameter cascaded plasma window was developed. The gas inlet, arc creation and plasma expansion segments are all contained in this model. A set of parameters including pressure, temperature, velocity and current distribution were obtained and analysed. In our first simulation, the isolation of 100 kPa and 50 Pa pressure has been realised, and some interesting phenomena occurred.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL069

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAL071

Preliminary Emittance Measurement of Laser Driven Proton Beam Employing a Quadruple Triplet Magnet

3818

SUSPL089

use link to see paper's listing under its alternate paper code

Wu,M.J. Wu, Y.X. Geng, Q. Liao, C. Lin, H.Y. Lu, Y.R. Lu, W.J. Ma, Y.R. Shou, X. Xu, X.Q. Yan, Y.Y. Zhao, J.G. Zhu, K. Zhu
PKU, Beijing, People's Republic of China

The Compact Laser Plasma Accelerator (CLAPA) has been built recently at Peking University, which composed of a 200TW laser acceleration platform and a beam line system. Proton with energy spread of <1%, up to 10 pC charge and different energies below 10 MeV have been produced and transported to the irradiation platform. Emittance is a critical parameter for beam transportation. The preliminary emittance measurement has been per-formed for CLAPA's proton beams using the quadrupole scan technique (QST). In the experiment, the focal spot size of the proton beam was changed by scanning the current of a quadrupole triplet magnet. The result shows that the normalized emittance is smaller than 0.01 mm·mrad for 5 MeV laser driven protons, which is on the same level of the previously reported work.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL071

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)