Abstract: [OBJECT]The present invention provides CT system capable of obtaining tomographic images having high in the image quality regardless of a change in the ambient temperature for a long period of time even if a cooling device is simple. [MEANS FOR ACHIEVING THE OBJECT] Computerized tomography system, comprising: a detecting device to detect radiation rays that penetrates an object to be detected; and a collimator to restrict radiation rays that are entered to the detecting device, wherein a separation gap for separating thermally the collimator and the detecting device is defined between an end surface 6f of the collimator 6 at the detecting device side and an end surface of the a detector holder at the collimator side in the detecting device, and the separation gap is hermetically sealed.

Abstract: The gas circuit breaker comprises a metal container filled with an insulating gas; first and second contacts disposed opposite each other in the metal container so that they can be brought into and out of engagement with each other; and a metal shield arranged in the metal container to enclose the two contacts. A part or a whole of the surface of the shield is oxidized and covered with a fluororesin layer. The gas circuit breaker with this construction can protect the shield surface against flaking and scores when subjected to mechanical impacts and can maintain high dielectric strength without increasing the size of the circuit breaker.