Research on a ferrite-silicon carbide hybrid high-order mode damper for accelerators
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摘要: 大电流加速器束管中,当带电粒子流通过束管时,会在束管中激励起高频场,为了降低对束流的影响,束管中产生的高次模需要利用阻尼器将高频场能量转换成热量并通过冷却装置导走。介绍了某混合型高次模阻尼器的研制及主要性能,阻尼器所采用的吸收材料为铁氧体和碳化硅,其通过金属化和钎焊实现与金属基板的焊接。通过CST和COMSOL软件分别开展了微波性能仿真和热仿真,对阻尼器的结构进行了优化设计。阻尼器的测试结果表明,该混合型阻尼器的吸收效率与计算结果在1.7 GHz以下频段相接近,在1.7 GHz以上高频段后,仿真吸收效率高于实测结果,相差较大;真空漏率、极限真空、水路耐压均满足超导高频腔设计需求。Abstract: In large current accelerator beam tubes, high-frequency fields are generated when charged particles circulate within the beam pipe. To mitigate the impact on beam current, it is essential to use high-order mode damper that convert the high-energy fields into heat, which can then be dissipated by a cooling system. This paper presents the research, fabrication, and key performance characteristics of a hybrid high-order mode damper. The absorbing materials utilized in the damper include ferrite and silicon carbide, which can be welded to metal substrates through metallization and welding techniques. Microwave performance simulations and thermal simulations were conducted using CST and COMSOL software, respectively, leading to an optimized damper structure. Test results demonstrate that the absorption efficiency of the hybrid damper aligns closely with calculated values in the frequency range below 1.7 GHz. However, while the simulated absorption efficiency exceeds the measured results above 1.7 GHz, significant discrepancies between the two sets of results were observed. Additionally, the vacuum leak rates, ultimate vacuum, and water resistance meet the design requirements for superconducting high-frequency cavities.
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Key words:
- high-order-mode /
- damper /
- ferrite /
- silicon carbide /
- welding
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表 1 混合型高次模阻尼器在吸收功率为10 kW时的温度分布仿真及测试结果
Table 1. Simulation and measurement results of temperature distribution for the hybrid high-order mode damper with an absorbed power of 10 kW
simulation results measurement results temperature difference between the inlet and outlet cooling water/℃ 2.3 1.1 表 2 混合型高次模阻尼器的性能测试结果
Table 2. Performance test results of the hybrid high-order mode damper
vacuum leak rates/(Pa·L·s−1) ultimate vacuum/Pa water-resistant/MPa 5×10−10 4.6×10−8 0.92 表 3 混合型高次模阻尼器的设计要求及性能测试结果
Table 3. Design requirements and performance test results of the hybrid high-order mode damper
absorbed
power/kWabsorption
efficiencyvacuum leak
rates/
(P·L·s−1)ultimate
vacuum/
Pawater-
resistant/
Mpatemperature difference
between the outlet and
inlet cooling water/℃design
requirements≥10 operating frequency band(0.6~3.0GHz)≥30%,
critical frequency bands(0.8~1.5GHz)≥50%≤1×10−7 ≤6.5×10−8 ≥0.9 ≤5 simulation
results10 operating frequency band(0.6~3.0GHz)≥53%,
critical frequency bands(0.8~1.5GHz)≥61%— — — — — — 2.3 measurement
results10.2 operating frequency band(0.6~3.0GHz)≥38%,
critical frequency bands(0.8~1.5GHz)≥60%5×10−10 4.6×10−8 0.92 1.1 -
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