Physical design and tuning of the long radio frequency quadrupole for accelerator-based boron neutron capture therapy

IF 1.4 3区物理与天体物理 Q3 INSTRUMENTS & INSTRUMENTATION

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment Pub Date : 2026-06-01 Epub Date: 2026-02-04 DOI:10.1016/j.nima.2026.171363

Haoquan Su , Haipeng Li , Wenlong Pan , Guoqing Kong , Wentao Deng , Jinglun Li , Jinwen Shuai , Sheng Wang

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引用次数: 0

Abstract

A continuous-wave radio-frequency quadrupole (RFQ) accelerator for boron neutron capture therapy (BNCT) has been designed, tuned, and experimentally validated. The RFQ delivers a beam energy of 2.8 MeV with a design input current of 25 mA. Optimized beam dynamics resulted in a transmission efficiency above 99.66% and a transverse emittance growth below 5.5%. The RF structure employs optimized cross-section and undercut geometries, achieving a cavity quality factor of 14, 286. π-mode stabilizing loops were introduced to enhance mode separation, and 100 tuners were implemented for field and frequency control. Multiphysics simulations predict a maximum temperature rise of 32.5 °C and a frequency shift of −91 kHz under CW operation. During low-power measurements and full-cavity tuning, a sag compensation method based on catenary fitting was developed to correct gravity-induced field distortions. After tuning, the operating frequency was set to 165.118 MHz, with dipole and quadrupole perturbative components controlled within ±1% and ±1.2%, respectively, and the measured Q value reaching 87% of the simulated value. Error analysis indicates that, within tuning tolerances, the transmission efficiency remains above 99.5%, the beam centroid shift is below 0.05 mm, and the output energy variation is less than 0.01 MeV. Beam commissioning demonstrated a output peak current of 22.1 mA and a transmission efficiency exceeding 94% at 125 Hz repetition rate and pulse width of 900 μs. Time-of-flight measurements yielded a proton energy of 2.812 ± 0.002 MeV, confirming the reliability of the RFQ design and tuning.

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基于加速器的硼中子俘获治疗的长射频四极物理设计与调谐

一种用于硼中子俘获治疗（BNCT）的连续波射频四极（RFQ）加速器已经设计、调谐并实验验证。RFQ的光束能量为2.8 MeV，设计输入电流为25 mA。优化后的光束传输效率达到99.66%以上，横向发射度增长低于5.5%。射频结构采用优化的横截面和凹边几何形状，实现了14286的腔质量因子。引入π模稳定环加强模式分离，采用100个调谐器进行场频控制。多物理场模拟预测，在连续波操作下，最高温升为32.5°C，频率漂移为- 91 kHz。在低功率测量和全腔调谐过程中，提出了一种基于悬链线拟合的垂度补偿方法来校正引力场畸变。调优后，将工作频率设置为165.118 MHz，偶极和四极微扰分量分别控制在±1%和±1.2%以内，实测Q值达到模拟值的87%。误差分析表明，在调谐公差范围内，传输效率保持在99.5%以上，光束质心位移小于0.05 mm，输出能量变化小于0.01 MeV。波束调试表明，在125 Hz重复频率和900 μs脉冲宽度下，输出峰值电流为22.1 mA，传输效率超过94%。飞行时间测量得到的质子能量为2.812±0.002 MeV，证实了RFQ设计和调谐的可靠性。

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来源期刊

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment 物理-光谱学

CiteScore

3.20

自引率

21.40%

发文量

787

审稿时长

1 months

期刊介绍： Section A of Nuclear Instruments and Methods in Physics Research publishes papers on design, manufacturing and performance of scientific instruments with an emphasis on large scale facilities. This includes the development of particle accelerators, ion sources, beam transport systems and target arrangements as well as the use of secondary phenomena such as synchrotron radiation and free electron lasers. It also includes all types of instrumentation for the detection and spectrometry of radiations from high energy processes and nuclear decays, as well as instrumentation for experiments at nuclear reactors. Specialized electronics for nuclear and other types of spectrometry as well as computerization of measurements and control systems in this area also find their place in the A section. Theoretical as well as experimental papers are accepted.