Linear accelerator heat variation jig

The present invention relates to a heat variation jig capable of changing and accommodating to thermal expansion caused by heat treatment. In the conventional application of brazing, the inside wall of the accelerator tends to wrinkle and deform, thereby shortening its entire length. The present invention provides a heat variation jig which overcomes this disadvantage. In the present invention, the jig has approximately the same value as that of heat expansion caused by heat treatment. Flanges are mounted at both ends of the heat-treated body. The thermal expansion characteristic of the body is compensated for by cooperation between one of the flanges and a spring; the cooperation between spring and a stainless bar allows the same heat expansion characteristics as the acceleration portion to be obtained. The stainless bar is mounted so that a drum body is pierced through the accleration portion. Applying the said jig, the entire length does not shorten. Within 100 minutes from the beginning of heating, heat expansion rapidly develops in the acceleration portion, with its expansion equalling that of the stainless bar in 165 minutes. The heat resistant spring has an accuracy of 4/1000. The present invention applies not only to brazing jigs but also to any kind of heat treatment. (M. Ishida)