Hf栅极栅电子发射的研究

Emission Characteristics of Hafnium-Metal Grid of Microwave Tubes

栅发射在栅控行波管及速调管中是较为普遍的现象,为了降低栅发射,通常采用高功函数金属作为栅极或在栅极表面沉积高功函数物质或沉积能与蒸散到栅极上的活性物质反应形成高功函数化合物的金属。本文直接采用纯金属Hf作为栅极,与普通Mo栅极对比,研究了Hf栅极在模拟电子管中管子激活前、阴极激活后栅发射的情况,并对氧化物阴极加速寿命中栅发射情况进行测试分析。结果表明:在阴极激活前后及寿命过程中,纯Hf栅极具有较小的栅发射电流。

The grid control microwave tube was fabricated,with its grid made of pure hafnium（Hf） metal,and its cathodes coated by liquid immersion,either with the porous Ba and W composite films or with the high-work function oxides films,respectively.The emission characteristics of the Hf grid were evaluated in the simulated microwave tube,before and after the activation of the cathodes,were evaluated and compared with those of the conventional molybdenum（Mo） grid.The preliminary results show that the emission currents of the Hf grid are lower than those of the Mo grid,before and after the cathode activation,and in the accelerated lifetime test as well.Possible mechanism was also tentatively discussed.