Electron Beam Production by Pyroelectric Crystals
Electron Beam Production by Pyroelectric Crystals
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热释电晶体产生电子束
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
S. Shafroth
中科院分区：
文献类型：
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作者：
J. Brownridge;S. Shafroth
热释电晶体用于产生能量大于170 keV的自聚焦电子束。不需要高压电源或电子枪。该系统的工作原理是简单地将LiNbO3或LiTaO3晶体在稀释气体中的温度改变约100摄氏度。给出了电子束能谱和正离子能谱及其谱图。晶体温度100℃的变化会引起自发的极化变化。极化的变化将表现为晶体表面电荷的变化。正是这种未补偿的电荷产生了电场，电场加速了电子或正离子，并产生了等离子体，等离子体又聚焦了电子或正离子。加速电子或正离子的来源是晶体表面附近电离的气体分子。当晶体表面是负电子加速远离它，正离子被吸引到表面。这些正离子减少了表面上的净负电荷，从而减少了电场，这导致电子能量随着时间的推移而减少，即使焦点性质保持不变。当表面为正极时，正极离子束能量也会随着时间的推移而减少。我们将展示视频剪辑、照片和电子数据，展示这些电子束的许多特征和应用。
Pyroelectric crystals are used to produce self-focused electron beams with energies greater than 170 keV. No high voltage power supply or electron gun is needed. The system works by simply changing the temperature of a crystal of LiNbO3 or LiTaO3 by about 100oC in dilute gas. Electron beam energy spectra as well as positive-ion-beam energy spectra and profiles are shown. A change in the crystal temperature of 100oC will cause a spontaneous change in polarization. The change in polarization will be manifested by a change in charge on the surface of the crystal. It is this uncompensated charge that produces the electric field, which accelerates the electrons, or the positive ions and gives rise to the plasma, which in turn focuses them. The source of the accelerated electrons or positive ions is gas molecules ionized near the crystal surface. When the crystal surface is negative electrons are accelerated away from it and positive ions are attracted to the surface. These positive ions reduce the net negative charge on the surface thereby reducing the electric field, which causes the electron energy to decrease over time even though the focal properties remain unchanged. When the surface is positive the reverse obtains and the positive ion beam energy decreases over time as well. We will present video clips, photographic and electronic data that demonstrate many of the characteristics and applications of these electron beams.