There is really no difference between a high-vacuum chamber and a common or laboratory vacuum chamber. They must both be designed to withstand an external pressure of one atmosphere, with a margin sufficient to eliminate the possibility of collapse. It is important to consider the external mounting forces on the tank, and the mass of equipment that might be operated inside the chamber.
Flat plates should be avoided in the construction. All surfaces must be curved in at least one dimension. The minimum weight solution would be a sphere, but that is difficult to fabricate because it has a double-curved surface, so a circular chamber with conical ends will be easier to fabricate.
The design problem is dependent on what will be inside the vacuum chamber. If there is room for internal baffles, or support plates, like in a vacuum reservoir, or a fuel tank, then the design can be simplified and the weight significantly reduced. An alternative topology is to fabricate ridges or fins on the outside surface of the chamber.
If the pressure difference is cycled often, then fatigue analysis will be needed. The fuselage of an aircraft has a lifetime determined by the number of flight cycles.
1. What is the purpose or application of this chamber?
2. What are the real dimensions, and the units?
3. What access to the chamber is required?
4. How many cycles of evacuation will occur?