Measurement of the polar intensity distribution of X-ray emitted by a Z-pinch

Summary form only given, as follows. The polar distribution of X-rays emitted by a Z-pinch has been inferred from the darkening of radio chromic film exposed on Double Eagle. For these measurements, a 3 cm wide film was mounted on a 72 cm radius arc with one end at the mid plane of the 2 cm long Al wire pinch. The width of the film was covered by three strips, 1 cm wide, of aluminized Kapton foil having one, two and three layers 8.3 /spl mu/m each over the entire 35 cm length of arc. These three layers of Kapton filtered out the UV radiation and provided three levels of film exposure at each angular position. The exposed radio chromic film was scanned with a microdensitometer and the results displayed as three curves of optical density (OD) variation with angle from the mid plane. The calibration procedure assumed that the same optical density results on different regions of radiochromic film filtered by different Kapton filters if the energy density on the film is the same in each case, ie: if U(/spl theta//sub n/)T/sub /spl alpha//=U(/spl theta//sub m/)T/sub /spl beta//. This allows us to relate the energy density U(/spl theta//sub n/), at a finite number of angular position /spl theta//sub n/ to the energy density at the mid plane as a combination of transmission ratios through the three Kapton filters. By adjusting the values of the transmission ratios, a smooth emitted intensity profile is obtained. The intensity is observed to decrease significantly more rapidly with angles from the mid plane than the cosine dependence that is expected. This variation may be indicative of radiation characteristics not currently considered. It also implies that the fluence near the mid plane may be higher than the value inferred from measurements made at some angle below it.