高功率激光放大器片腔洁净度实验研究

在氙灯放电泵浦过程中，放大器片腔内材料在高强度氙灯光辐照下，存在显著的热解过程，产生大量的微米级悬浮粒子。在两种实验条件下对粒子数进行了测量:一是放大器氙灯泵浦结束之后悬浮粒子的自然消散过程；二是氙灯泵浦结束之后利用大气流量的超纯氮气冲洗片腔之后的粒子数测量。研究结果表明，正常情况下，氙灯泵浦结束后片腔洁净度达到了10~50万级气溶胶的水平(在粒子直径Φ 0.5 μm的水平上)。利用大气流量的超纯N2气冲洗片腔能够在短时间内显著地提高片腔的洁净度。

A method for high power microwave beam scan by spin and swing

For high power microwave application, the offset parabolic antennas have advantages of lower side lobes, lower standing wave ratio, high efficiency and avoiding breakdown comparing with the center feed parent. Without any rotary RF joint in the high power microwave transmit system, the scan can be achieved by spinning the reflector around the axe of the feed and swinging the reflector and feed around the focus in the ( x,z ) plane by using a vacuum flexible elliptical waveguide. By geometric approach, the scan functions are presented. The scan properties are characterized with the maximum elevation angle range at a definite distance. The renations between the scan characteristics and the antenna geometric and spin swing parameters are given for the antenna design. The spin swing single offset parabolic antenna has small transmission loss and simpler mechanical scan construction.