Pulsed soft X-ray tube of novel design

A ceramic envelope X-ray tube was developed to give short pulses (10^-7seconds) of very intense, soft radiation (peak dose rate of the order of 10⁹roentgens/second, anode voltage 20 KV). The triple-oxide cathode is planar, has a 9/16" diameter, and is separated from the target by a normally closed, magnetically operated shutter which prevents barium oxide evaporation from cathode to target. A pulsed electromagnet opens the shutter in synchronism with a cathode "hot shot" for" increased emission and application of anode voltage. The tube is operated space charge limited to avoid cathode sparking. The target is a layer of gold, about 0.6 microns thick, evaporated directly onto the 0.010" beryllium window. The output radiation pulse has been found to exceed 160 roentgens for a peak target current of 180 amperes. Novel features of design, construction, and circuitry will be briefly described.