Abstract: A small superconducting undulator with a period less than 1 cm, referred to here as a “super-mini” undulator. The embodiment of the super-mini encompasses of two coils wound bifilarly around a pair of bobbins in a racetrack configuration, such that the currents in adjacent coil segments run antiparallel to each other. If such coils are arranged alongside each other, separated only by a small gap on the order of a couple of millimeters, a spatially alternating magnetic field is produced that makes a passing electron beam undulate and emit undulator radiation. The wound bobbins are mounted within a frame and combined with upper and lower pole pieces to close gap between the wire coils.

Abstract: The present invention permits solder joints to be made directly to via and through holes without the solder being wicked into the vias or through holes, by filling plated through holes with an epoxy or cyanate fill composition. When cured and overplated, the fill composition provides support for the solder joint and provides a flat solderable surface for the inter-connection. In certain embodiments, the cured fill compositions, offer a further advantage of being conductive. The invention also relates to several novel methods for filling through holes with such fill compositions, and to resistors located in through holes and vias.