Abstract: Apparatus is provided for use in detecting the input voltage applied to a radiation source operating at an unknown voltage within a given voltage range. The apparatus includes a set of radiation absorbing filters including a first filter which includes a first chemical element and a second filter which includes a second chemical element. These elements are chosen so that the filters exhibit different radiation absorption characteristics within the given voltage range. The filters are adapted to be positioned so that the first and second filters are irradiated by the radiation source with the radiation impinging upon a surface of each filter and partially absorbed thereby as it passes therethrough so as to exit therefrom as attenuated radiation. A detector receives the attenuated radiation passed by the first and second filters and provides first and second signals having magnitudes which vary with the attenuated radiation respectively passed by the first and second filters.

Abstract: Apparatus is provided for use in detecting the peak voltage applied to a radiation source operating at an unknown input voltage. The apparatus includes a set of radiation absorbing filters including a first filter which includes a first element that exhibits a known K-absorption edge and a second filter constructed of a second element so that the filters exhibit essentially the same radiation absorption characteristics below the K-absorption edge of the first filter. The filters are adapted to be positioned so as to be irradiated by the radiation source so that the radiation impinges upon a surface of each filter and is partially absorbed as it passes therethrough so as to exit therefrom as attenuated radiation. A detector, such as X-ray film or a pair of photodiodes, is positioned for receiving the attenuated radiation passed by the first and second filters and provides an output indication when the radiation passed by the filters is differently attenuated.