Applied Sciences

Research

Jump to: Review

17 pages, 10043 KiB

Open AccessArticle

Research and Design of the RF Cavity for an 11 MeV Superconducting Cyclotron

by Yue Wu, Zi-Feng He, Wei-Shi Wan, Pan-Pan Zheng and Hua-Fei Yu

Appl. Sci. 2024, 14(9), 3549; https://doi.org/10.3390/app14093549 - 23 Apr 2024

Viewed by 313

Abstract

In contrast to the room temperature cyclotron, the superconducting cyclotron’s high operational magnetic field and small extraction radius lead to a magnet design with a reduced radius. This limits the space available for the RF cavity in the 11 MeV superconducting cyclotron, necessitating [...] Read more.

In contrast to the room temperature cyclotron, the superconducting cyclotron’s high operational magnetic field and small extraction radius lead to a magnet design with a reduced radius. This limits the space available for the RF cavity in the 11 MeV superconducting cyclotron, necessitating a more compact RF cavity design. By using the transmission line theory, the complex structure of the quarter-wavelength coaxial cavity can be represented as a microwave circuit. Through relevant theoretical analytical formulas, equivalent circuit parameters can be derived. The resonant frequency of the RF cavity is then determined using the equivalent circuit method. The optimization of the RF cavity structure was achieved by creating a numerical model and conducting finite element numerical calculations on the high-frequency resonant system. The comparative results between the equivalent circuit and numerical calculations indicate that the frequency error remains within 0.1%, validating the compact RF cavity design. A multiple linear regression analysis facilitates the prediction of resonance frequency across various parameter variables. By analyzing the fitting formula, RF cavity machining error requirements are established, ensuring a prediction error within 1%, thus meeting engineering design criteria. Full article

(This article belongs to the Special Issue Advances in Particle Acceleration: Novel Techniques, Instruments and Applications)

► Show Figures

Figure 1

15 pages, 2877 KiB

Open AccessArticle

Plasma Accelerator Utilizing the Medium of Near-Earth Space for Orbital Transfer Vehicles

by Alexander R. Karimov, Paul A. Murad, Vladimir A. Yamschikov and Dmitriy S. Baranov

Appl. Sci. 2023, 13(24), 13195; https://doi.org/10.3390/app132413195 - 12 Dec 2023

Cited by 1 | Viewed by 848

Abstract

The development of plasma accelerators for spacecraft propulsion that can capture space matter and energy shows great promise for spacecraft advancement. Such a technical approach offers a viable solution to the challenges associated with traditional rocket fuel. In the present paper, we explore [...] Read more.

The development of plasma accelerators for spacecraft propulsion that can capture space matter and energy shows great promise for spacecraft advancement. Such a technical approach offers a viable solution to the challenges associated with traditional rocket fuel. In the present paper, we explore the utilization of interplanetary matter as fuel for plasma thrusters on space vehicles, specifically for flights within the vicinity of Earth. Herein, solar radiation is considered a source of energy for the ionization and acceleration of particles captured from the space environment. Full article

(This article belongs to the Special Issue Advances in Particle Acceleration: Novel Techniques, Instruments and Applications)

► Show Figures

Figure 1

18 pages, 9204 KiB

Open AccessArticle

Design of a Miniaturized Electron Cyclotron Resonance Ion Source for High-Voltage Proton Accelerator

by Hua-Fei Yu, Zi-Feng He, Ming-Hua Zhao, Wei-Shi Wan, Huan-Ling Liu, Yue Wu, Wen-Zhuang Lv, Da-Yong Zhou and Huan-Ting Lu

Appl. Sci. 2023, 13(15), 8831; https://doi.org/10.3390/app13158831 - 31 Jul 2023

Cited by 1 | Viewed by 1415

Abstract

The Electron Cyclotron Resonance (ECR) ion source fulfills high-current, high-efficiency, and compactness requirements for high-voltage proton accelerators. It is a cathode-free source that uses microwaves to heat a magnetically confined plasma, so there is no cathode loss resulting in a short service life. [...] Read more.

The Electron Cyclotron Resonance (ECR) ion source fulfills high-current, high-efficiency, and compactness requirements for high-voltage proton accelerators. It is a cathode-free source that uses microwaves to heat a magnetically confined plasma, so there is no cathode loss resulting in a short service life. We finished the design for a miniaturization ECR ion source system, including a microwave system and source body. The traditional microwave system’s scale, which is approximately 1 m, has been reduced to 0.234 m, and the transmission efficiency is greater than 90%. The influence of cavity size and magnetic field distribution on gas ionization is analyzed under the condition that the outer size of the permanent magnet ring is limited, and the optimal scheme of cavity size and saddle-shaped magnetic field distribution is obtained. This design meets the requirement of fitting the ion source system into the restricted space in the high-voltage accelerator’s head. Full article

(This article belongs to the Special Issue Advances in Particle Acceleration: Novel Techniques, Instruments and Applications)

► Show Figures

Figure 1

17 pages, 32881 KiB

Open AccessArticle

Nb₃Sn Cavities Coated by Tin Vapor Diffusion Method at Peking University

by Gai Wang, Shengwen Quan, Lin Lin, Manqian Ren, Jiankui Hao, Fang Wang, Fei Jiao, Feng Zhu, Senlin Huang, Xueqing Yan and Kun Zhu

Appl. Sci. 2023, 13(15), 8618; https://doi.org/10.3390/app13158618 - 26 Jul 2023

Viewed by 877

Abstract

Nb₃Sn-coating experiments on samples and single-cell cavities were conducted at Peking University (PKU) to understand the Nb₃Sn growth process using the vapor diffusion method. The evaporation of tin and tin chloride used in the vapor diffusion process was simulated [...] Read more.

Nb₃Sn-coating experiments on samples and single-cell cavities were conducted at Peking University (PKU) to understand the Nb₃Sn growth process using the vapor diffusion method. The evaporation of tin and tin chloride used in the vapor diffusion process was simulated and experimentally analyzed. The results show that the nucleation process is generally uniform, and the atomic ratios of Nb/O and Sn/O were found to be 1:2 within the 10 nm surface of the nucleated samples. Three tin sources were distributed along the cavity axis to obtain a uniform grain size on the cavity surface, and a surface tin content of 25~26% was achieved. The tin segregation effect was found in long-time coatings or coatings with insufficient tin, resulting in a low Sn% and bad cavity performance. By overcoming the tin segregation problem, a Nb₃Sn cavity with a 750 nm grain size was produced by 1200 °C coating for 80 min and 1150 °C annealing for 60 min. The acceleration gradient reached 17.3 MV/m without quenching and an obvious Q-slope at 4.2 K. The relationship between coating recipes and vertical test results is discussed and conclusive advice is provided in this paper. Full article

(This article belongs to the Special Issue Advances in Particle Acceleration: Novel Techniques, Instruments and Applications)

► Show Figures

Figure 1

18 pages, 3139 KiB

Open AccessArticle

DYNAMION—A Powerful Beam Dynamics Software Package for the Development of Ion Linear Accelerators and Decelerators

by Stepan Yaramyshev, Winfried Barth, Simon Lauber, Maksym Miski-Oglu, Anna Rubin, Uwe Scheeler, Hartmut Vormann and Markus Vossberg

Appl. Sci. 2023, 13(14), 8422; https://doi.org/10.3390/app13148422 - 21 Jul 2023

Viewed by 861

Abstract

Numerous ambitious particle accelerator facilities, based on proton and ion linear accelerators, have recently been in development for fundamental research, as well as for industrial applications. The advanced design of such new machines, as well as the upgrade and optimization of existing linacs, [...] Read more.

Numerous ambitious particle accelerator facilities, based on proton and ion linear accelerators, have recently been in development for fundamental research, as well as for industrial applications. The advanced design of such new machines, as well as the upgrade and optimization of existing linacs, requires adequate, precise and reliable tools to simulate beam dynamics. The software package DYNAMION, created about 30 years ago, is undergoing systematic improvement and further development in order to characterize modern ion linacs and to provide solutions for its intrinsic complex problems. The DYNAMION code features Front to End beam dynamics simulations under space charge conditions in a linac system, comprising an arbitrary sequence of accelerating-focusing structures and beam transport lines. The evolution of a macroparticle ensemble could be analyzed at a high level of specification. A 3D distribution of the external electrical field (RFQ, DTL) is modeled using integrated internal solvers. Optionally, a 3D electromagnetic field mapping, supplied by specialized external codes, could be used. The recent status of the DYNAMION software package is presented in this paper. Furthermore, the performance of the code is demonstrated on the basis of its application for various linear accelerator/decelerator projects. Full article

(This article belongs to the Special Issue Advances in Particle Acceleration: Novel Techniques, Instruments and Applications)

► Show Figures

Figure 1

12 pages, 2632 KiB

Open AccessArticle

Upgrades of a Small Electrostatic Dust Accelerator at the University of Stuttgart

by Yanwei Li, Marcel Bauer, Sebastian Kelz, Heiko Strack, Jonas Simolka, Christian Mazur, Maximilian Sommer, Anna Mocker and Ralf Srama

Appl. Sci. 2023, 13(7), 4441; https://doi.org/10.3390/app13074441 - 31 Mar 2023

Viewed by 1263

Abstract

In this paper, we describe the upgrade of a small electrostatic dust accelerator located at the University of Stuttgart. The newly developed dust source, focusing lens, differential detector and linac stage were successfully installed and tested in the beam line. The input voltage [...] Read more.

In this paper, we describe the upgrade of a small electrostatic dust accelerator located at the University of Stuttgart. The newly developed dust source, focusing lens, differential detector and linac stage were successfully installed and tested in the beam line. The input voltage range of the dust source was extended from 0–20 kV to 0–30 kV. A newly developed dust detector with two differential charge sensitive amplifiers is employed to monitor particles with speeds from several m/s to several km/s and with surface charges above 0.028 fC. The post-stage linac provides an additional acceleration ability with a total voltage of up to 120 kV. The entire system of this dust accelerator works without protection gas and without a complex high voltage terminal. The volumes to be pumped down are small and can be quickly evacuated. The new system was used to accelerate micron- and submicron-sized metal particles or coated mineral materials. Improvements in the acceleration system allow for a wider variety of dust materials and new applications. Full article

(This article belongs to the Special Issue Advances in Particle Acceleration: Novel Techniques, Instruments and Applications)

► Show Figures

Figure 1

23 pages, 3445 KiB

Open AccessArticle

X-ray Free Electron Laser Accelerator Lattice Design Using Laser-Assisted Bunch Compression

by Haoran Xu, Petr M. Anisimov, Bruce E. Carlsten, Leanne D. Duffy, Quinn R. Marksteiner and River R. Robles

Appl. Sci. 2023, 13(4), 2285; https://doi.org/10.3390/app13042285 - 10 Feb 2023

Cited by 1 | Viewed by 1509

Abstract

We report the start-to-end modeling of our accelerator lattice design employing a laser-assisted bunch compression (LABC) scheme in an X-ray free electron laser (XFEL), using the proposed Matter-Radiation Interactions in Extremes (MaRIE) XFEL parameters. The accelerator lattice utilized a two-stage bunch compression scheme, [...] Read more.

We report the start-to-end modeling of our accelerator lattice design employing a laser-assisted bunch compression (LABC) scheme in an X-ray free electron laser (XFEL), using the proposed Matter-Radiation Interactions in Extremes (MaRIE) XFEL parameters. The accelerator lattice utilized a two-stage bunch compression scheme, with the first bunch compressor performing a conventional bulk compression enhancing the beam current from 20 A to 500 A, at 750 MeV. The second bunch compression was achieved by modulating the beam immediately downstream of the first bunch compressor by a laser with 1-

μ m

wavelength in a laser modulator, accelerating the beam to the final energy of 12 GeV, and compressing the individual 1-

μ m

periods of the modulated beam into a sequence of microbunches with 3-kA current spikes by the second bunch compressor. The LABC architecture presented had been developed based on the scheme of enhanced self-amplified spontaneous emission (ESASE), but operated in a disparate regime of parameters. Enabled by the novel technology of the cryogenic normal conducting radiofrequency photoinjector, we investigated an electron beam with ultra-low emittance at the starting point of the lattice design. Our work aimed at mitigating the well-known beam instabilities to preserve the beam emittance and suppress the energy spread growth. Full article

(This article belongs to the Special Issue Advances in Particle Acceleration: Novel Techniques, Instruments and Applications)

► Show Figures

Figure 1

Review

Jump to: Research

36 pages, 7254 KiB

Open AccessReview

Transformative Technology for FLASH Radiation Therapy

by Reinhard Schulte, Carol Johnstone, Salime Boucher, Eric Esarey, Cameron G. R. Geddes, Maksim Kravchenko, Sergey Kutsaev, Billy W. Loo, Jr., François Méot, Brahim Mustapha, Kei Nakamura, Emilio A. Nanni, Lieselotte Obst-Huebl, Stephen E. Sampayan, Carl B. Schroeder, Ke Sheng, Antoine M. Snijders, Emma Snively, Sami G. Tantawi and Jeroen Van Tilborg

Appl. Sci. 2023, 13(8), 5021; https://doi.org/10.3390/app13085021 - 17 Apr 2023

Cited by 7 | Viewed by 3846

Abstract

The general concept of radiation therapy used in conventional cancer treatment is to increase the therapeutic index by creating a physical dose differential between tumors and normal tissues through precision dose targeting, image guidance, and radiation beams that deliver a radiation dose with [...] Read more.

The general concept of radiation therapy used in conventional cancer treatment is to increase the therapeutic index by creating a physical dose differential between tumors and normal tissues through precision dose targeting, image guidance, and radiation beams that deliver a radiation dose with high conformality, e.g., protons and ions. However, the treatment and cure are still limited by normal tissue radiation toxicity, with the corresponding side effects. A fundamentally different paradigm for increasing the therapeutic index of radiation therapy has emerged recently, supported by preclinical research, and based on the FLASH radiation effect. FLASH radiation therapy (FLASH-RT) is an ultra-high-dose-rate delivery of a therapeutic radiation dose within a fraction of a second. Experimental studies have shown that normal tissues seem to be universally spared at these high dose rates, whereas tumors are not. While dose delivery conditions to achieve a FLASH effect are not yet fully characterized, it is currently estimated that doses delivered in less than 200 ms produce normal-tissue-sparing effects, yet effectively kill tumor cells. Despite a great opportunity, there are many technical challenges for the accelerator community to create the required dose rates with novel compact accelerators to ensure the safe delivery of FLASH radiation beams. Full article

(This article belongs to the Special Issue Advances in Particle Acceleration: Novel Techniques, Instruments and Applications)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Advances in Particle Acceleration: Novel Techniques, Instruments and Applications

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (8 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI