Abstract: A motion detection system including a lens arranged to focus infrared radiation; a variably positionable optical attenuator arranged for variable positioning thereof opposite the focusing lens, operable for variably attenuating infrared radiation focused by the focusing lens, an extent and a magnitude of the variable attenuation being dependent on a position and on a set of physical characteristics of the variably positionable optical attenuator; a PIR sensor positioned opposite the focusing lens and the variably positionable optical attenuator, operable for sensing the focused and attenuated infrared radiation; and a human motion detection indication generator operable for ascertaining whether an intensity of infrared radiation sensed by the PIR sensor is above a human-generated infrared radiation detection threshold and, responsive thereto, for generating an indication of detection of human motion.

Abstract: A radiation detector is provided. The radiation detection comprises a semiconductor crystal for detecting radiation. The semiconductor crystal comprises a top surface, a bottom surface, and at least one side surface. At least one anode is arranged on at least one of the top surface, the bottom surface, and the at least one side surface. At least one cathode is arranged on at least another one of the top surface, the bottom surface, and the at least one side surface. The at least one anode each has a stripe shape, the at least one cathode each has a planar or curved shape, and the at least one cathode and the at least one anode extend in parallel with respect to each other to a length substantially equal to that of the anode. Such an electrode structure can improve energy resolution and detection efficiency of the radiation detector effectively.