Update of the lifetime performance of Dendresist vacuum insulator coating

Composite material vacuum insulators have been developed over the last few years to improve the lifetime performance of the vacuum interface of the large multiterrawatt X-ray testing facilities. These composite insulators consist of a base of polyurethane coated by a dendrite resistant epoxy compound called Dendresist. The polyurethane is mechanically rugged and withstands the shock environment while the epoxy vacuum surface coating was developed to minimize the dendrite damage caused by the high voltage electron environment. These composite insulators have now been used for over a year on the following operational facilities: PITHON, Double-Eagle and Decade Module 2 (DM2). This paper reviews the design and development of the new insulator material and updates the lifetime database from the operational X-ray facilities.