I’ve been writing my dissertation lately, and for the most part it’s going pretty well…but I can drive myself crazy deciding how broad a discussion to take when describing a very narrow subject area.

For instance I’ve been brushing up on all my old x-ray optics papers.  I’ve decided to spend the most time on how energy-selective optics work, focusing on dynamical diffraction and the Rowland circle.  I worked out the Darwin width for a perfect crystal with and without dispersion corrections.  Still, who the hell knows what a Darwin width is…so I decided to back up and talk about where Bragg diffraction actually comes from.   I thought it would be nice to do it in terms of form factors to explain dispersion corrections later, so I decided to do it in reciprocal know with a form factor for a collection of atoms on a lattice.

But then I thought, what if you want to know what the individual form factor is for an atom?  …and for that matter for an individual electron.  Which meant that I was all the way back to classical Thomson radiation, where the electric field of the x-ray induces the electron to wiggle back and forth, causing dipole radiation.  But wait–why does an electron radiate when it accelerates?

While I believe that there’s value in ‘seeing the forest among the trees’ as Jerry quips all the time, I think I’m starting taking it way too far…