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核爆炸瞬间释放的中子、γ射线和核电磁脉冲对磁性材料及器件会产生各种影响,引起性能变化。中子能使磁性材料产生永久性损伤的主要原因是高能中子与材料相互作用使晶格原子产生位移效应。γ辐射可引起电离效应,产生瞬时光电流,对材料及器件造成瞬时干扰,甚至永久性损伤。静态实验证明,当中子流量达10~(16)中子/厘米~2、γ剂量率为10~8拉德(硅)/秒时,磁性器件的性能无显著改变。核爆瞬间,在相当大的范围内产生强大的电磁脉冲,其电场强度为10~4—10~5伏/米,脉冲波形持续时间为几百10~(-9)秒,频谱范围从10~2千赫兹到10~2兆赫兹。由于磁性器件外部屏蔽不完善或结构本身的孔隙,使外部电磁脉冲可以渗透到内部。即使屏蔽很完善,在几百公里范围内的强γ辐射也会在器件内部感生内电磁脉冲。这些都会干扰或破坏磁性器件的正常工作性能。因此在核辐射条件下,研究这些材料和器件的动态性能具有重要意义。
Neutron, γ-ray and nuclear electromagnetic pulses released instantaneously from a nuclear explosion have various effects on magnetic materials and devices and cause changes in performance. The main reason that neutrons can make permanent damage to magnetic materials is that the interaction between high energy neutrons and materials causes displacement of lattice atoms. Gamma radiation can cause ionization effects, producing instantaneous photocurrent, instantaneous interference with materials and devices, and even permanent damage. Static experiments show that there is no significant change in the performance of the magnetic device when neutron flux reaches 10-16 neutron / cm 2 and γ dose rate is 10-8 Vdc / s. Nuclear explosion moment, in a very large range of strong electromagnetic pulse, the electric field strength of 10 ~ 4-10 ~ 5V / m, pulse waveform duration of hundreds of 10 ~ (-9) seconds, the spectrum range from 10 ~ 2 kHz to 10 ~ 2 MHz. Due to imperfections in the external shielding of the magnetic device or the porosity of the structure itself, external electromagnetic pulses can penetrate into the interior. Strong gamma radiation, within a few hundred kilometers, induces internal electromagnetic pulses inside the device, even with well-shielded. These will interfere with or destroy the normal performance of magnetic devices. Therefore, under the condition of nuclear radiation, it is of great significance to study the dynamic performance of these materials and devices.