EXPERIMENTAL-OBSERVATION OF TRANSMISSION-EMISSION-TYPE AND SELF-EMISSION-TYPE RADIATION TRANSPORT IN X-RAY-PRODUCED PLASMAS

Radiation transport in x-ray-produced plasmas was experimentally studi ed. Thin foils of low-Z and high-Z materials were heated by external x rays from one side, and x rays emanating from the opposite side were observed. Careful measurements were made to distinguish between self-e mitted x rays from the heated plasma and a transmitted component of th e heating x rays. The results clearly demonstrate the existence of two types of radiation transport. The transmitted x rays play a major rol e in radiation transport in the case of a low-Z material which is opti cally thin after burnthrough, and the self-emitted x rays play a major role in the case of a high-Z material which is optically thick even a fter burnthrough.