Matters which are worthy of attention in the welding of NYZ medical accelerating tube are described. The accelerating tube should be divided into many parts to be welded according to the welding facility. The weld seams between parts

as far as possible

should be chosen near the observation windows and far away from the low temperature sections of the hydrogen stove. Weld interfaces must contact well each other during assembling

and remain perpendicular to the vertical line to minimize deform and displacement between rings and plates during sling and to assure tightness of seams. Before the short parts and the whole accelerating tube are sent into the stove and after welded

the straightness of assembling must be checked.