How do I make something exactly? This is a very difficult question. Before studying experimental physics, I have never thought about a tolerance. But, after studying, I realized it is so important to make a sort of decision. In the CAD world, everything is perfect except a few stupid mistakes, which are usually done by myself. In the Geant4, I also have to decide the tolerance, which is called cut and some special parameters. If they are inappropriate for a simulation, total time consuming will be longer than a suitable one.
Today I struggled to find out the solution about the tolerance about an electron fiber detector.
All of the drawing of an part seems to be fine. All mechanical parts also are good quality. They fit well each other. If one of the bolts, which can be used to connect each other, is not fixed well, every performance is good. But if all of bolts is fixed well, then one part, which is a slide that can move the fiber bundle mount and cart of photomultiplier in two directions, can move very tough. It might come from the mismatch two parallel supporter, which can support SKL liner small slide, the distance tolerance between two slides and so on. I do not know what a really problem is.
I am afraid of saying something exactly.
Doing physics is to accept the limitation of human being.
Doing physics is to understand what human being is.
Doing physics is to know what human being can do.