What material is used to make the case of an X-ray tube?

Question

can tell me the reason?

Answer 1

Glass is a good thing to make it out of because it is easy to make glass very clean. It needs to be very clean because an x-ray tube is under high vacuum. If the inside of your container isnt very clean (metals absorb hydrogen, which can come out of the metal when it is under vacuum) it can outgas and you will no longer have a high vacuum. The pressure inside a vacuum electronic device is usually in the range of 10^-7  to 10^-9 torr, for comparison atmospheric pressure is 760 torr.

You need high vacuum so that the electrons in the x-ray tube will not hit anything on their way from the cathode to the anode/target. If they hit something on the way it could form a plasma inside the tube which would short out your system and you would burn out your power supply instead of making x-rays.

Answer 2

Outer case is lead.

Answer 3

The case is blown glass.

Here is an example where an x-ray tube is made from

hand-blown glass with a magnesium coating on the inside: