物理学报
物理學報
물이학보
2015年
8期
086801-1-086801-7
,共1页
绝缘样品%表面电位%电子产额%数值模拟
絕緣樣品%錶麵電位%電子產額%數值模擬
절연양품%표면전위%전자산액%수치모의
insulating sample%surface potential%electron yield%numerical simulation
采用数值计算和实验测量相结合的方法,阐明了高能电子束照射下绝缘厚样品的表面电位和电子产额动态特性。结果表明:由于电子在样品内部的散射和输运,沿着深度方向,空间电位先缓慢下降到最小值,然后逐渐升高并趋近于零;随着电子束照射,样品的表面电位逐渐下降,可至负千伏量级,电子总产额逐渐增大至一个接近于1的稳定值;电子束停止照射后,长时间放置下,表面电位将逐渐升高,但带电并不会消除;表面电位随电子束能量的升高近似线性下降,随入射角的增大而升高,而随样品厚度的增大仅略有下降。
採用數值計算和實驗測量相結閤的方法,闡明瞭高能電子束照射下絕緣厚樣品的錶麵電位和電子產額動態特性。結果錶明:由于電子在樣品內部的散射和輸運,沿著深度方嚮,空間電位先緩慢下降到最小值,然後逐漸升高併趨近于零;隨著電子束照射,樣品的錶麵電位逐漸下降,可至負韆伏量級,電子總產額逐漸增大至一箇接近于1的穩定值;電子束停止照射後,長時間放置下,錶麵電位將逐漸升高,但帶電併不會消除;錶麵電位隨電子束能量的升高近似線性下降,隨入射角的增大而升高,而隨樣品厚度的增大僅略有下降。
채용수치계산화실험측량상결합적방법,천명료고능전자속조사하절연후양품적표면전위화전자산액동태특성。결과표명:유우전자재양품내부적산사화수운,연착심도방향,공간전위선완만하강도최소치,연후축점승고병추근우령;수착전자속조사,양품적표면전위축점하강,가지부천복량급,전자총산액축점증대지일개접근우1적은정치;전자속정지조사후,장시간방치하,표면전위장축점승고,단대전병불회소제;표면전위수전자속능량적승고근사선성하강,수입사각적증대이승고,이수양품후도적증대부략유하강。
The surface potential and electron yield dynamic characteristics of an insulating thick sample under high-energy electron beam irradiation are obtained by combining the numerical simulation and experimental measurement. The numerical model takes into account the electron scattering, charge trapping, and charge transport. The results show that due to the electron scattering and transport, the space charge is weakly positive in the near surface and strongly negative inside sample; along the depth direction, the space potential decreases to a minimum value slowly, and then increases gradually and finally tends to zero; with the electron beam irradiation, the surface potential decreases to the negative kV magnitude gradually, and the total electron yield gradually increases to a stable value that is slightly less than unity. After stopping irradiation, the surface potential increases gradually, but charges are not eliminated completely. The surface potential decreases linearly with the increase of the beam energy, and increases with the increase of the incident angle, however it decreases slightly with the increase of the sample thickness.