excited

pulserver.virtual.excited()

Return the slabs the excitation pulses of the cache beside a sequence file excite; None where one excites every isochromat.

A pulse’s slab holds the fields at which it changes the magnetization at rest by at least threshold of the most it changes it, at its nominal amplitude or twice it: the pulse is played on a line of isochromats along its gradient, turned by rotation as simulate() turns it. A pulse played without a gradient, or under one that changes during it, excites every isochromat, and so do pulses played under more than 16 gradients, as a ZTE scan’s are. Only the pulses the cache labels excitations are counted: what the others tip into the transverse plane outside the slabs, such as the free induction decay of an imperfect refocusing pulse, is left out of a scan simulated in them.