Hilsabeck T J, Hares J D, Kilkenny J D, Bell P M, Dymoke-Bradshaw A K L, Koch J A, Celliers P M, Bradley D K, McCarville T, Pivovaroff M, Soufli R, Bionta R
General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA.
Rev Sci Instrum. 2010 Oct;81(10):10E317. doi: 10.1063/1.3479111.
A 5 ps gated framing camera was demonstrated using the pulse-dilation of a drifting electron signal. The pulse-dilation is achieved by accelerating a photoelectron derived information pulse with a time varying potential [R. D. Prosser, J. Phys. E 9, 57 (1976)]. The temporal dependence of the accelerating potential causes a birth time dependent axial velocity dispersion that spreads the pulse as it transits a drift region. The expanded pulse is then imaged with a conventional gated microchannel plate based framing camera and the effective gating time of the combined instrument is reduced over that of the framing camera alone. In the drift region, electron image defocusing in the transverse or image plane is prevented with a large axial magnetic field. Details of the unique issues associated with rf excited photocathodes were investigated numerically and a prototype instrument based on this principle was recently constructed. Temporal resolution of the instrument was measured with a frequency tripled femtosecond laser operating at 266 nm. The system demonstrated 20× temporal magnification and the results are presented here. X-ray image formation strategies and photometric calculations for inertial confinement fusion implosion experiments are also examined.
利用漂移电子信号的脉冲展宽演示了一台5皮秒选通分幅相机。脉冲展宽是通过用随时间变化的电势加速光电子衍生的信息脉冲来实现的[R. D. 普罗瑟，《物理学杂志E》9，57（1976年）]。加速电势的时间依赖性导致了与产生时间相关的轴向速度色散，在脉冲穿过漂移区时使其展宽。然后用传统的基于选通微通道板的分幅相机对展宽后的脉冲进行成像，与单独的分幅相机相比，组合仪器的有效选通时间缩短了。在漂移区，通过一个强轴向磁场防止电子图像在横向或像平面上散焦。对与射频激发光电阴极相关的独特问题的细节进行了数值研究，最近还构建了基于这一原理的原型仪器。用一台工作在266纳米的三倍频飞秒激光测量了该仪器的时间分辨率。该系统展示了20倍的时间放大率，结果在此给出。还研究了惯性约束聚变内爆实验的X射线图像形成策略和光度计算。
