Exploring Carbon New phases by Laser-Induced Shock Waves

通过激光诱导冲击波探索碳新相

基本信息

批准号：
08405044
负责人：
KONDO Ken-ichi
金额：
$ 20.35万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

Metastable phases of diamond, amorphous and nanocrystalline diamond, were produced by SCARQ (shock compression and rapid quenching) method based on the shock-gun technology, This method was also applied to a laser-shock technology, which was developed in this study. Two-types of laser-shock method were investigated ; one was the direct use of laser-induced ablation pressures, and the other was the use of the laser-driven flyer impact, For the latter, thin aluminum foils were accelerated by a high power Nd : YAG pulse laser and impacted PMMA window placed at a certain distance. Arrival time of the flyers was detected by a streak camera. Spatial changes in the arrival time revealed the curved flyer shape depending on the laser energy distribution which resulted in velocity distribution. Moreover, these profiles were strongly dependent on the distance from focal point of laser. Therefore, it was difficult to reduce the focal spot size less than 0.1 mm whose value was required for achieving the diamond transition pressure of 50 GPa. These experimental data were described by computer simulation based on one-dimensional hydro-code.The structural change of fullerene films subjected to laser-shock compression using the laser was investigated by Raman scattering. Some samples transformed into fullerene polymer, and the photo-induced structural change of fullerene was also investigated.An infrared radiometer for the accurate measurement of shock temperature was developed in order to investigate shock-induced, dynamic reaction processes of materials. To determine the IR-radiometer, the shock temperature measurements of carbon tetrachloride were conducted below 10 GPa, and the results confirmed that the system was available to measure relatively moderate shock temperatures lower than 1000 K.However, the system might be available at higher temperature in the case of laser-shock because of the small shock-compressed area.

基于冲击枪技术的Scarq（冲击压缩和快速淬火）方法生产了钻石，无定形和纳米晶体钻石的可稳定阶段，该方法还应用于本研究中开发的激光震动技术。研究了两种激光震动法。一个是直接使用激光诱导的消融压力，另一个是使用激光驱动的传单撞击，对于后者，通过高功率ND：YAG脉冲激光器加速了薄的铝箔，并在某个距离处放置了PMMA窗口。传单的到达时间是通过条纹摄像头检测到的。到达时间的空间变化揭示了弯曲的传单形状，具体取决于激光能量分布，从而导致速度分布。此外，这些曲线很大程度上取决于与激光焦点的距离。因此，很难将焦点尺寸降低小于0.1 mm的焦点尺寸，这些焦点是达到50 GPA的钻石过渡压力所需的值。这些实验数据通过基于一维水电代码的计算机仿真来描述。通过拉曼散射研究了使用激光进行激光震压压缩的富勒烯膜的结构变化。一些样品转化为富勒烯聚合物，还研究了光诱导的富勒烯的结构变化。为了研究电击诱导的材料动态反应过程，开发了精确测量冲击温度的红外辐射计。为了确定IR-radioter，在10 GPA以下进行了四氯化碳的冲击温度测量值，结果证实该系统可用于测量相对中等的休克温度低于1000 K的相对中等的休克温度。