Rules: 1. practicing Ph.Ds. (Physics) not permitted to reply 'till
Tuesday after 1800 PDT. [Especially JD, ME, and BW]
2. No Googling, or other references. This is to use your general
knowledge and "common sense".
Friday I had a delightful discussion w/ an expert neutron scatterer.
He pointed out some interesting non intuitive behavior that even
occasionally experts overlook during their practice. (This is a hint.)
1. The common scheme is to have a source of neutrons selected for
velocity (wave length) followed by a crystal and then a detector. If
the analyst wishes to know the time (duration) of interaction w/ the
crystal, what dimension (length) should (s)he use. Why?
2a. Alignment of the above w/, for example, a LASER is not sufficient, why?
2b. The answer to 2a suggests a handy method of velocity selection.
(Hints: It's analogous to one of the methods used to velocity select
electrons. Give away hint: Think parabola.)