共查询到20条相似文献,搜索用时 187 毫秒
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模拟光电阴极灵敏度测试仪对GaAs阴极激活光源进行校准,并对透、反射阴极光电流比值对灵敏度的影响进行了讨论,实验结果证明,P^ 衬底和阴极组件激活灵敏度的差别主要来源于台外工艺质量的影响。 相似文献
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透射式GaAs光电阴极研究 总被引:2,自引:2,他引:0
本文叙述了透射式GaAs光电阴极的原理和制作过程,详细地研究了透射式GaAs光阴极的激活工艺,获得了500μA/1m的积分灵敏度. 相似文献
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我们在一台制作第三代象增强器的超高真空系统中安装了俄歇(Auger)能谱仪,以其对GaAs光电阴极的制备过程进行在线监测分析,其中包括选择性腐蚀过程的俄歇观测,阴极激活前清洁措施的效果评价和Cs-O激活过程中As/Ga俄歇信号比对光电灵敏度的影响,Cs源纯度的分析及对光电发射的影响。根据分析结果,激活出了1000μA/lm的反射式光电阴极和500μA/lm的透射式光电阴极。 相似文献
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透射式GaAs光电阴极激活技术研究 总被引:3,自引:0,他引:3
通过对成像器件GaAs负电子亲合势(NEA)光电阴极激活技术的研究,运用分析仪器进行工艺质量在线监测,在大、薄、匀的GaAs外延层激活出的台内阴极灵敏度大于1300μA/lm。 相似文献
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NEA光电阴极的(Cs,O)激活工艺研究 总被引:7,自引:3,他引:4
在自行研制的负电子亲和势光电阴极性能评估实验系统上,首次利用动态光谱响应技术和变角X射线光电子能谱(XPS)表面分析技术研究了GaAs光电阴极的(Cs,O)激活工艺.获得了首次导Cs、(Cs,O)导入以及(Cs,O)循环的优化激活条件.XPS分析给出GaAs(Cs,O)的最佳激活层厚度为0.82 nm,首次导Cs达到峰值光电发射时的Cs覆盖率为0.71个单层.在优化激活条件下,可以在国产反射式GaAs上获得1025 μA/lm的积分灵敏度. 相似文献
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GaAs光电阴极在进行Cs-O激活前.激活层表面必须达到原子级洁净。最常用且最有效的洁净方法是高温热清洗法。然而.在热清洗过程中对处在真空系统中的光电阴极表面温度进行精确测量却是非常困难的。本文采用四极质谱仪对GaAs光电阴极激活前的热清洗过程进行分析.确定了最佳的热清洗温度及热清洗工艺,较好地解决了GaAs光电阴极激活前的热清洗工艺问题。 相似文献
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利用X射线光电子能谱(XPS)仪对激活后的GaAs真空电子源进行了随时间衰减变化的XPS分析,分析发现了电子源阴极表面各元素百分含量随时间的变化,揭示了杂质气体吸附造成的偶极矩方向的改变是电子源灵敏度显著下降的主要原因.基于上述结论,通过分析真空系统中杂质气体的吸附过程,推导并得到了GaAs电子源衰减模型.该模型从理论上揭示了GaAs电子源的指数衰减规律以及寿命与真空度的反比关系,与实验现象完全一致.
关键词:
电子源
X射线光电子能谱
衰减模型
真空度 相似文献
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Earley L.M. Scott G.L. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1990,18(2):247-249
A miniature laser-triggered high-voltage vacuum switch with a fused KCl and Ni cathode is discussed. The switch uses metal-ceramic construction with a sapphire window in the anode to allow the laser beam to strike the cathode surface. Reliable triggering is achieved with only 20 μJ of laser energy. The switch was operated with a gap voltage ranging from 500 V to 3 kV, with switching currents up to a 5 kA peak. Switch life greater than 1000 shots without performance degradation has been observed on 50 prototype devices. The function time of the switch varies from 10±1 ns at 3 kV to 100±50 ns at 500 V 相似文献
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M. M. Nikitin 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(2):285-290
Cathodic and anodic discharges are effective sources of coating material ionized fluxes. Of special interest is the use of
anodic discharges, particularly discharges with a thermoelectronic cathode. The discharge forms fluxes in high vacuum with
regulated ionization and the absence of micro liquid droplets. The initiation conditions and characteristics of the discharge
in the voltage range from 50 to 500 V with currents up to 5 A were investigated. The dependence of vacuum, interelectrode
distance, and cathode heating temperature were considered. Conditions for the production of coating material fluxes with maximum
ionization were established. 相似文献
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真空残气对GaAs阴极发射性能的影响 总被引:5,自引:1,他引:4
针对三代微光像增强器的GaAs阴极灵敏度下降,分析真空残气对阴极发射性能的影响。实验结果表明,有害气体是造成阴极灵敏度下降的主要因素。 相似文献
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In this paper, a vacuum system is employed to compare the emission stabilities of the same ZnO cathode in a sealed field emission (FE) device and under ultrahigh vacuum (UHV) conditions. It is observed that the emission current is more stable under the UHV level than in the device. When all conditions except the ambient gases are kept unchanged, the emission current degradation is mainly caused by the residual gases in the sealed device. The quadrupole mass spectrometer (QMS) equipped on the vacuum system is used to investigate the residual gas components. Based on the obtained QMS data, the following conclusions can be drawn: the residual gases in ZnO-FE devices are H2, CH4, CO, Ar, and CO2. These residual gases can change the work function at the surface through adsorption or ion bombardment, thereby degrading the emission current of the cathode. 相似文献
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With the improvement of the current level of power grids, the requirements of the opening level of the vacuum switches are also increasing. Vacuum arc cathode spots provide steam and electrons and, to a certain extent, determine the opening capacity of the vacuum switch. In this paper, a vacuum arc cathode spot research platform based on the de-mountable vacuum chamber is constructed. The characteristics of the vacuum arc cathode spots under the transverse magnetic field (TMF) contacts are assessed by a high-speed charge coupled device. The experimental results show that the cathode spot diffusion process can be divided into three processes through cathode spot distribution, arc voltage and current: initial diffusion stage of cathode spots, unstable motion stage of cathode spots, and extinguishing stage. The motion mode of cathode spots during unstable motion stage can be divided into cathode spots group stagnation (CSGS) to multi-cathode jet (MCJ) switch mode, cathode spots group motion (CSGM) to MCJ switch mode, CSGM mode, and MCJ mode. The effects of peak current and contact diameter on unstable motion mode were analysed. 相似文献
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The energy and current balances in the diode unit of a high-current pulsed electron accelerator (350–500 keV, 60 ns, 250 J per pulse) are compared for an explosive emission cathode (made of graphite, copper, or carbon felt) and a multipoint (graphite or copper) cathode. The planar diode with the continuous cathode is shown to be more efficient in terms of conversion of the applied energy to electron energy (more than 90%) despite a delay in the plasma surface formation. With the impedance of the planar diode matched to the output resistance of the nanosecond generator, the efficiency of the diode does not depend on the time of plasma formation on the cathode. In the case of the graphite cathode, the plasma formation delay reduces the fraction of slow electrons in the forming electron beam and reduces electron losses in anode foil when the beam is extracted from the vacuum space of the diode chamber into the reactor. 相似文献
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本文基于IE514分离规结构, 建立了碳纳米管阴极电离规物理模型, 根据电离规标准方程, 利用离子光学模拟软件SIMION 8.0分别研究了电极电压对灵敏度和Igrid/Ie的影响. 结果表明, 随着阳极/门极电压比值增大(Vgrid/Vgate), Igrid/Ie也将增大, 然而, 当阳极电压增大时, 会导致灵敏度降低, 进而影响真空测量下限的延伸; 该模拟结果与相关文献报道的实验结果符合性很好. 因此, 选择合适的电极电压, 将有利于提高灵敏度, 增大阳极电流, 进一步延伸真空测量下限. 本文所采用的数值模拟方法可推广应用于各种新型碳纳米管阴极极高真空电离规的研发和理论分析中, 为解决极高真空测量难题提供了有效的研究途径.
关键词:
碳纳米管阴极电离规
电极电压
灵敏度
阳极电流 相似文献