Abstract: An irradiator is disclosed for irradiating dosimeters type used to monitor environmental exposure or exposure of personnel to radiation. The irradiated dosimeters are used as standards against which dosimetry analysis equipment is calibrated. The invention provides an improved design for an irradiator which permits uniform irradiation of dosimeters over a wide range of radiation doses and which can provide both primary and secondary standards for calibration purposes. The irradiator includes a shielded housing designed with an optimum geometry to ensure uniform dosage across the face of the dosimeter, a filter to prevent undesirable scattered radiation from reaching the dosimeter during exposure, and a movable radiation attenuator to permit large differences in desired dose to be easily accommodated.

Abstract: An over-door interphone system for telephonic communication between a master station unit inside of a house and a remote station unit outside of an entrance door of the house is provided with a night-vision monitoring device. The night-vision monitoring device has a television camera comprising a solid-state camera sensitive to an infrared light. The solid-state camera is responsible for successfully incorporating the television camera within a less bulky housing of the remote station unit as well as for monitoring the image of a visitor by the camera without being noticed. Also, there can be utilized an illumination device producing an infrared which is hardly perceived by the visitor, ensuring monitoring of the visitor at night without a giving unfavorable impression thereto.