1. An x-ray device comprising:a housing configured for maintenance of a low fluid pressure environment in a chamber of the housing, the housing having a window, the housing being substantially opaque to x-rays other than the window, which is substantially transparent to x-rays;
a driving roller;
a motor for driving the driving roller;
a contact rod at least partially within the chamber;
a continuous band looped around the driving roller and in contact with the contact rod, the continuous band defining a loop with at least a portion of the contact rod within the loop, the continuous band and the contact material being comprised of materials such that varying contact between the continuous band and the contact material generates relative charge imbalance.