Abstract: A hand held radiation detector may be used for scanning of a surface from a distance to obtain a gross indication of temperature variations in the surface. The radiation detector is provided with a nosepiece having a conical cup therein which can be placed directly against a surface. The radiation sensor views the surface through the cup to obtain an accurate indication of temperature substantially independent of the emissivity of the surface. The radiation sensor and a temperature sensor are potted with high conductivity material in an insulating sleeve within the nosepiece. The nosepiece is of high conductivity material and is thermally connected to a main housing which serves as a heat sink. Temperature indications are obtained from the sensed radiation indication by means of a piecewise linear gain analog circuit.

Abstract: A hand held radiation detector is adapted for scanning the subject while a bar graph at one end of the detector is observed. The field of view of the radiation detector is variable by means of removable lens assemblies which have Fresnel lenses positioned at the focal lengths of the lenses from the radiation sensor. The lens assemblies are matched to provide the same flux density to the radiation sensor independent of the field of view. Crosshairs provided on the rear of a lens support assist in aiming the radiation detector. The time constant of the display is varied with the sensitivity of the display.

Abstract: A radiation detector includes a flat housing 14 having a radiation sensor 16 at one end thereof and a bar graph display 18 at the other end thereof. The bar graph display provides an indication of radiation sensed from a limited surface area as the sensor is scanned across an extended surface area. The width of the housing 14 is such that, when the housing is held at about arm's length in the line of sight, the width defines a field of view which approximates the field of view of the radiation sensor.