Validation of photon emission based signals using an energy window network in conjunction with a fundamental mode discriminator circuit

A system for detecting photon emissions, each occurring at an energy of interest within a range thereof, comprising:

• a crystal detector assembly having an input confronting said photon emissions and responsive thereto to derive electrical parameter signals each having an amplitude corresponding with said energy of interest;
• a first comparator network responsive to each said electrical parameter signal and having an output, L, of given pulse width when said signal exhibits a said amplitude of value above a threshold value;
• a second comparator network responsive to each said electrical parameter signal and having an output, H, of pulse width substantially equal to said given pulse width when said signal exhibits a said amplitude of value above an upper limit value;
• an asynchronous, sequential, fundamental mode discriminator circuit responsive to said output, L, and said output, H, having three stable states a, b, and c, and having an event output and a no-event output condition, and having said no-event output condition when in a said stable state, said discriminator circuit transitioning from said state a to said state b upon the occurrence of said output, L, without the presence of said output, H, responsive when in said stable state b to the occurrence of said output H in the presence of said output L to transition with a said no-event output condition to said stable state c, and responsive when in said stable state c to the termination of said outputs L and H to transition with a said no-event output condition to said stable state a;
• and
• control means responsive to each derived said event output for effecting an evaluation thereof.