Ueda Tatsuki, Fujioka Shinsuke, Nozaki Shinya, Azuma Rumiko, Chen Yen-Wei, Nishimura Hiroaki
Institute of Laser Engineering, Osaka University, 2-6, Yamada-oka, Suita, Osaka, 565-0871, Japan.
Rev Sci Instrum. 2010 Jul;81(7):073505. doi: 10.1063/1.3460623.
A coded imaging and decoding (image reconstruction) scheme was developed for diagnosing a hot and dense region emitting hard x-rays and neutrons in laser-fusion plasmas. Because the imager was a uniformly redundant array of penumbral aperture (URPA) arranged in an M-matrix, URPA leads to N times (N: the total number of apertures) enhancement of signal intensity in comparison with a single penumbral aperture. A recorded penumbral image was reconstructed by a computer-based heuristic method to reduce artifacts caused by noises contained in a penumbral image. Applicability of this technique was investigated by imaging x-rays emitted from laser-produced plasmas, demonstrating a spatial resolution of 16 microm. Under the present conditions, the spatial resolution was determined dominantly by a detector resolution (10.5 microm) and a signal-to-noise ratio of the obtained penumbral image.
开发了一种编码成像和解码(图像重建)方案,用于诊断激光聚变等离子体中发射硬X射线和中子的高温高密度区域。由于成像器是排列成M矩阵的半影孔径均匀冗余阵列(URPA),与单个半影孔径相比,URPA可使信号强度增强N倍(N为孔径总数)。通过基于计算机的启发式方法重建记录的半影图像,以减少半影图像中所含噪声引起的伪影。通过对激光产生的等离子体发射的X射线进行成像,研究了该技术的适用性,显示出16微米的空间分辨率。在当前条件下,空间分辨率主要由探测器分辨率(10.5微米)和所获得半影图像的信噪比决定。