Versatile X-Ray Beam Scanner

A chopper for interrupting a beam of particles, the beam of particles characterized by a propagation direction, the chopper comprising:

• a. an obscuring element substantially opaque to passage of the particles in the propagation direction;
• b. at least one through-hole in the obscuring element adapted for passage through the obscuring element of particles in the propagation direction, the through-hole characterized by a tapered dimension in a plane transverse to the propagation direction;
• c. an actuator for moving the obscuring element in such a manner as to cause at least a portion of the beam of particles to traverse the at least one through hole on a periodic basis.

A chopper for interrupting a beam of particles, the beam of particles characterized by a propagation direction, the chopper comprising:

• a. an obscuring element substantially opaque to passage of the particles in the propagation direction;
• b. at least one through-hole in the obscuring element adapted for passage through the obscuring element of particles in the propagation direction, the through-hole characterized by a rectangular cross section in a plane transverse to the propagation direction.

A collimator for narrowing a beam of particles, the beam of particles characterized by a propagation direction, the collimator comprising:

• a. an obscuring element substantially opaque to passage of the particles in the propagation direction;
• b. a gap in the obscuring element adapted for passage through the obscuring element of particles in the propagation direction, the gap characterized by a length taken along a long dimension and a width taken along narrow dimension, both the long and narrow dimensions transverse to the propagation direction,
• wherein the width of the gap varies as a function of distance along the long dimension relative to an edge of the gap.