X-ray streak camera tube with two photocathodes

Jin Li, Pin Yang, Zhi-Wen Yang, Xing Zhang, Shen-Ye Liu, Jian-Jun Dong, Zheng-Hua Yang, Kuan Ren, Ying-Jie Li, Lu Zhang, Xin Hu, Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
2022 Wuli xuebao  
<sec>The time-resolved X-ray spectroscopy measurement system based on X-ray streak camera technology is indispensable diagnostic equipment in the study of laser inertial fusion research and high-energy-density physics. However, limited by the effective photocathode length of the X-ray streak tube, the time-resolved spectral measurement system usually used has the shortcomings of narrow spectrum range and poor spectral resolution.</sec><sec>In order to overcome the shortcomings, a novel
more » ... nel streak tube is developed, which consists of a photocathode, a prefocusing electrode group in temporal direction, an electric quadrupole lens electrode group, a main focusing electrode group in temporal direction, a deflector plate, and a phosphor screen.The photocathode has two slits. When X-rays are incident, two electron beams can be emitted simultaneously. The electric quadrupole lens electrode group is composed of 8 arc electrodes. Two electric quadrupole lenses are formed by the 8 arc electrodes in the spatial direction. The two electron beams emitted from the cathode of the streak tube are first accelerated and prefocused by the prefocusing electrode group in the time direction, and then compressed by the main focusing electrode group in the time direction. In the spatial direction, the two electron beams are focused by the two electric quadrupole lenses independently.This novel streak tube structure can focus two electron beams at the same time, thereby increasing the effective photocathode length and maintaining the compact structure of streak tube without increasing the aberration.</sec><sec>The cathode voltage of the designed streak tube is –12kV, the distance from cathode to grid is 5 mm, and the cathode-grid field strength is 2.4kV/mm. The cathode is divided into two sections, the spacing between sections is about 13mm, the length of each section is more than 20 mm, the magnification of the image converter tube is about 1.56 times, the distance between the cathode and the phosphor screen is 300 mm, and the longest size along the cathode direction is 90 mm. The test results of the performance of the streak tube show that the actual effective cathode length of the developed tube reaches 44 mm, the spatial resolution is better than 15 lp/mm, and the deflection sensitivity is better than 40mm/kV. The effective cathode and spatial resolution of the tube can be increased to 50 mm and 25 lp/mm lp/mm by further optimizing the structure of the tube and removing the image intensifier with a high sensitivity image recording system, respectively.</sec>
doi:10.7498/aps.71.20221194 fatcat:oylu2u4wp5e7xk5gikiaxp5ifq