Development and test of a ∼800kV, ∼35 kA air insulated LTD pulser for radiography application

AWE is replacing its current Mevex X-ray machine (~800kV, 35kA, 60ns pulse) to improve reliability and maintainability. A design using a Linear Transformer Driver (LTD) insulated with dry air at atmospheric pressure has been developed by ITHPP. A testbed using 3 cavities, made from 2 bricks of two GA35460M 8nF, 100kV capacitors, a multigap multichannel switch and a magnetic core, has been developed and extensively tested [1]. This led to the development of the full generator that uses 17 cavities in series to produce an 800kV output voltage on a vacuum insulated line and a 23-25Ω diode. The ~4.3m long inner stalk is cantilevered by the back of the pulser and is positioned by a 3 point adjustable support. This setting is completed by 2 internal tensioning cables to compensate for flexing and provide fine adjustment of the diode end. The assembly of the generator has been done on the 1^st half of 2015. The machine can be operated with negative and positive polarity outputs to satisfy operational requirements given by AWE. The tests results of this generator in both polarities are presented in terms of output performances. The reproducibility and reliability of the full system is also analyzed.