中性粒子分析仪的研究现状

中性粒子分析仪(NPA)作为托卡马克(Tokamak)装置的重要诊断工具,在等离子体物理研究中具有重要科学意义和广泛应用前景。NPA通过精确测量从等离子体中逃逸的中性粒子,可获取等离子体内部的关键信息,包括离子温度、快离子能谱分布和氢同位素比例等。自20世纪60年代首台NPA问世以来,经过60余年的技术发展,其诊断能力已经实现了质的飞跃,并且发展出了多种类型的NPA。针对中国环流3号(HL-3)装置的快离子物理研究,四川大学与核工业西南物理研究院联合研制了基于LYSO+SiPM探测器的串联式平行电磁场结构的NPA(E//B NPA)。该E//B NPA已安装到HL-3装置,并在等离子体放电实验中成功测量到高能量氘(D)中性粒子能谱,为今后HL-3装置中性粒子诊断及快离子研究奠定了坚实的技术基础。

DEVELOPMENT OF A NEUTRAL PARTICLE ANALYZER FOR THE HL-1M TOKAMAK

A neutral particle energy analyzer (NPA) has been developed to investigate the energy spectra of neutral particles emitted from the HL1M tokamak plasma. The NPA consists of a pair of 45o parallel electrostatic plates, a gas stripping cell, a column of channeltrons for recording ions,and the relevant instrumentation and software. There are eight energy channels in the NPA with energy ratio of 8 between the lowest energy channel and the highest one. Calibration experiment is the key issue for the development of NPA. Calibrations of energy, energy resolution and registration efficiency have been carried out. The scattering of neutrals through the stripping gas impingement, which is severe for the particle energy we concerned, has also been measured to calibrate the registration efficiency accurately. With the NPA, the heating effects of lower hybrid wave on the plasma ions in the HL1M tokamak for different plasma parameters, especially for different plasma density, have been investigated.