Hasegawa, B.H., Stebler, B., Rutt, B.K., Martinez, A., Gingold, E.L., Barker, C.S., Faulkner, K.G., Cann, C.E. and Boyd, D.P., 1991. A prototype high‐purity germanium detector system with fast photon‐counting circuitry for medical imaging. Medical physics, 18(5), pp.900-909.