Design and experimental progress of a 105/140 GHz dual-frequency MW-level gyrotron
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摘要: 介绍了105/140 GHz双频兆瓦级回旋管的设计和最新实验进展。该回旋管的谐振腔、准光模式变换器、BN输出窗采用了双频共用的设计,电子枪采用了双频复用的双阳极磁控注入枪,收集极采用单级降压。在现有实验室电网功率容量有限的情况下,进行脉冲调试,得到的实验结果为:在重频1 Hz、ms连续短脉冲条件下,在105 GHz点和140 GHz点脉冲功率分别达到710 kW和1.057 MW,脉宽0.7 ms,对应总效率分别为34%和49%。在105 GHz点通过脉宽延展和老炼,进一步得到300 kW/2 s和400 kW/1 s的秒级脉宽实验结果,BN窗片的温度在两种状态下温度分别达到606 ℃和503 ℃,波束频率单一,没有杂模。实验基本上验证了该器件的物理设计。Abstract: The design and latest experimental progress of a 105/140 GHz dual-frequency megawatt-level gyrotron for fusion applications are presented. The resonant cavity, quasi-optical mode converter and BN output window of the gyrotron adopt the design of dual-frequency sharing, the electron gun adopts the triode magnetron injection gun with dual-frequency multiplexing, and the collecting pole adopts the single-stage depressed collector. The experimental results are as follows: under the ms short-pulse condition with repetitive rate of 1 Hz, pulse powers of 710 kW at 105 GHz and 1.057 MW at 140 GHz have been achieved. The pulse width is 0.7 ms, and the total efficiency is 34% at 105 GHz and 49% at 140 GHz, respectively. Through pulse width extension and aging, the experimental results of 105 GHz/300 kW/2 s, 105 GHz/400 kW/1 s and 140 GHz/400 kW/1 s are obtained. The temperature of BN window reaches 606 ℃, 503 ℃ and 633 ℃, respectively, in the three states. The frequencies during long-pulse operations are stable, indicating that there are no parasitic modes. The experiment basically verifies the physical design of the device.
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表 1 105/140 GHz MW回旋管设计参数
Table 1. Design parameters of the 105/140 GHz MW gyrotron
No. parameter value 1
2
3output power
pulse width
total beam voltage1.0 MW
continuous wave
−81 kV4 beam current 40 A 5 MIG triode type 6 cavity mode TE18,7@105 GHz; TE24,9@139.3 GHz 7 working magnetic field 4.1 T@105 GHz; 5.5 T@140 GHz 8 output mode quasi-Gaussian beam 9 window BN disk for short-pulse operation; CVD diamond for MW-level CW operation 10 collector single-stage depressed collector (SDC) 11 efficiency >30% (45% with SDC) -
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