Abstract: A method of detecting and suppressing extraneous radiation influences in radiometric measurements utilizes, in addition to the measurement channel that extends at least essentially over the entire usable pulse amplitude spectrum, at least one substitute channel that encompasses only a fractional range of the usable pulse amplitude spectrum. The measurement channel (MK) and substitute channel (EK) are calibrated in terms of the same variables, such as fill level or volume. A comparison between the measurement values, defined by the respective pulse rates of the measurement channel and substitute channel, is brought about in such a way that the value of the linkage varies significantly if extraneous radiation occurs.

Abstract: A method of detecting and suppressing extraneous radiation influences in radiometric measurements utilizes, in addition to the measurement channel that extends at least essentially over the entire usable pulse amplitude spectrum, at least one substitute channel that encompasses only a fractional range of the usable pulse amplitude spectrum. The measurement channel (MK) and substitute channel (EK) are calibrated in terms of the same variables, such as fill level or volume. A comparison between the measurement values, defined by the respective pulse rates of the measurement channel and substitute channel, is brought about in such a way that the value of the linkage varies significantly if extraneous radiation occurs.

Abstract: A method for discrimination and simultaneous or separate measurement of single or multiple electronic events in an opto-electronic detector, such as a photo-multiplier, wherein information for the discrimination of these events is obtained from the signal progression occurring at the detector output within a predeterminable time window. According to this method, a characteristic parameter (T.sub.M ; t.sub.b -t.sub.a) is obtained for the temporal "center of gravity" of the progression of the signal itself or its integral over the time window (T.sub.F), the value of which is compared with a reference value (T.sub.S ; C.sub.1) which this parameter assumes during a single photo-electron event.

Abstract: A counting tube for detecting radioactive radiation exclusively uses cathode pads for signal detection, which are disposed electrically insulated on the interior of an inner wall of the counting tube housing opposite the sample. A discrete electronic evaluation element is preferably allocated to each cathode element, which makes possible parallel evaluation of the counting tube signal. The cathode pads are in particular laminated in the form of a metal-coated conductive surface on a support plate made of an insulating material. The field of application of such counting tubes with the exclusive use of cathode pads is in particular in connection with multiple counting tubes where the partial areas of a total area to be measured are intended to be individually detected and evaluated.

Abstract: A method for measuring the radioactivity in eluates from liquid chromatography columns in which a portion of the eluate stream is split off and mixed with a scintillation fluid in a timed sequence wherein the volume of eluate and the volume of scintillation cocktail are quantitatively and reproduceably controlled. An apparatus for the practice of this method comprising a two-position valve on the affluent stream, a two-position valve on a pumped closed loop of scintillation cocktail a means for simultaneously setting the position of each valve and a mixing chamber discharging to a scintillation counter is also described. By the practice of this method, it is possible to determine the radioactivity of the eluate as well as to preserve a sample of the eluate for further analysis.