Abstract: Cell, whose interior (3) is filled with liquid, whose radioactivity is measured by a scintillator or other detector install thereon. The invention consists of equipping the cell with rinsing means in order to wash the cell side wall (2) and the sealing or blanking plate (13) with respect to impurities deposited thereon and interfering with the measurement as a result of their natural radioactivity. Blowing means are provided above the free surface of the radioactive liquid in order to oppose its vaporization, which would produce other deposits.

Abstract: A continuous sample detector includes a sample chamber, a cell body and one or more standard sources of radiation. Mounted in the sample chamber, the cell body has a cell, a coil of transparent tubing through which the sample solution continuously passes during the measurement. The standard source of radiation is mounted adjacent to the cell body. The detector also includes a sensor mounted and arranged proximate the cell and the standard source to encounter relative reciprocation for allowing the sensor to alternately sense radiation of the cell and the standard source. The detector is operated by connecting sample lines to the cell body. The sensor and cell are then positioned to detect radiation from the cell with the sensor, while a sample flow is pumped through the cell. The system is calibrated by disposing the sensor and the standard source to detect radiation from the standard source with the sensor, without disconnecting the sample lines from the cell body.

Abstract: A scintillation measurement system for measuring optical events produced by scintillators in response to the radioactive decay of a constituent or constituents of a sample to be measured comprises a sample support for positioning a sample in a sample well; a bismuth germanate (BGO) scintillation crystal, such as Bi.sub.4 Ge.sub.3 O.sub.12, located adjacent the sample well; a plurality of photodetectors located outside the bismuth germanate crystal for detecting optical events occurring in the sample well or in the bismuth germanate crystal and converting those optical events into electrical pulses; and a pulse analyzing system for receiving the electrical pulses from the photodetectors and determining whether such pulses represent .alpha., .beta. or .gamma. events. This system can be used with samples containing .alpha., .beta. and .gamma. emitters, or any combination thereof.

Abstract: A method and apparatus for determining .beta.-ray emitters to determine radioactivity of tritium with a high sensitivity and without contamination of a radiation recording plate with radioactivity, wherein a plastic microplate is provided having a number of flat bottomed wells interconnected by a plurality of shallow vent channels having a depth ranging from about 2 mm to 6 mm formed therein. The radiation recording plate is disposed facing tile microplate through a spacer. A metal exposure container which is sealed accommodates the resulting assembly of the microplate, spacer and the radiation recording plate.

Abstract: A device for counting liquid scintillation samples which can count a single sample or several samples simultaneously. A transport system moves samples from a storage section to a counting section. The samples are placed on sample plate holders to assist the transport system in movement of the sample from the storage section to the counting section.

Abstract: Methods and apparatus are provided for identifying a radionuclide in a liquid sample containing at least one unknown radionuclide, in which specific properties which are essentially linear over extended quench ranges are employed as the primary basis for identifying the radionuclide. For example, the endpoint or maximum energy of a sample is related to Mantel's average energy or a property proportional to the average energy (such as isotope center number) in order to establish characteristic relationships for radionuclides of interest; comparison of measured values with characteristic values for specific radionuclides may in some cases be sufficient to identify a radionuclide unambiguously. The relationships between isotope center number, full width of the spectrum at half its maximum height and maximum energy may be exploited to provide a pair of characteristic equations for each radionuclide.

Abstract: A liquid scintillation medium for homogeneous flow systems which comprises solvent, fluor and optionally surfactant, wherein the solvent comprises benzyltoluene. The solvent may comprise the positional isomers of benzyltoluene, and other solvents such as diphenylethane. This new solvent system for use in flow-through scintillation counting is characterized by low viscosity, high flash point and low vapour pressure.

Abstract: A method and a liquid scintillation counter for measuring a sample, a mixture of the specimen to be analysed and a scintillator, in a liquid scintillation counter where the sample (14) is measured with two photo multiplier tubes (23, 24) situated on different sides of the sample. The photo multiplier tubes situated on different sides of the sample operate in coincidence. Asymmetric samples are measured in such a way that the counting efficiency is measured with the photo multiplier tubes (23, 24) operating in coincidence ad calculated using the amount of coincidence pulses, whereas the amplitude and the pulse height distribution are measured only with one photo multiplier tube (23 or 24).

Abstract: A method for use in liquid scintillation counting for detecting, recording and analyzing scintillation phenomena due to ionizing radiation in a device having a measuring chamber into which the sample is placed and which sample is measured with at least two light detectors. The occurrences of the measurement are recorded so completely that the measurement can be reconstructed and the analyzing principle can be decided afterwards.

Abstract: A metal ion detection and quantification system in which the displacement of a radioactive isotope from a material that binds both the metal ion of interest and the radioactive isotope. The material in question binds the radioactive isotope with less force than the isotope of interest. The extent of release of the radioactive isotope is used to determine the concentration of the metal ion of interest. In one embodiment of the invention, the material used to bind the metal ion and radioactive ion is a protein of the metallothionein class of proteins.

Abstract: An invention for preventing optical crosstalk in a process of counting liquid scintillation samples deposited in a sample plate, the sample plate composed of a plurality of sample wells, the optical crosstalk being caused by mutual optical affection between samples deposited in the sample wells. Sample wells are provided with tubes made of material impermeable but reflective or scattering for scintillation light generated by the samples.

Abstract: A method for scintillation counting and a scintillation counter exploiting a coincidence technique, in which the coincidence resolving time is flexible and can be automatically adjusted to fit the scintillation characteristics of each sample separately. This is accomplished by measuring during a short initial period the pulse length of the scintillation pulses, and adjusting the coincidence resolving time of the coincidence analyzer before the actual counting of the sample.

Abstract: The present invention is a scintillator which emits light in response to radiation. The scintillator is capable of being reversibly changed between solid and liquid phases, whichever is desired, by temperature control. The scintillator comprises a fluorescent substance for converting radiation energy into light energy; a solvent which transfers radiation energy to the fluorescent substance and dissolves and diffuses the fluorescent substance and a radioactive substance acting as an object of measurement to thereby homogenize them; and a fixing substance which enables the solvent, the fluorescent substance and the radioactive substance to be fixed in a solid state and also liquified upon heating, the fixing substance being capable of phase change reversibility.

Abstract: An arrangement for counting liquid scintillation samples on bottom-window multi-well sample plates in a liquid scintillation counter. The sample plates include a plurality of samples wells having light impermeable side walls and a light permeable bottom sheet which covers and forms the bottoms of said sample wells. The liquid scintillation counter includes at least one photomultiplier tube and a sample plate holder. The sample plate holder includes a device to hold sample plates of different sizes and a device to enable transporting of the sample plate holder by the scintillation counter. For preventing light passage between sample wells in the permeable bottom sheet a light permeable adhesive foil provided with black lines or other light passage preventing treatment between the sample wells is attached to the bottom side of the sample plate.

Abstract: An arrangement for counting liquid scintillation samples on a sample plate in a liquid scintillation counter having at least one photomultiplier tube. The sample plate contains a plurality of open-bottomed wells sealed with at least one filtration membrane impregnated with a solid meltable scintillator. The arrangement includes a sample plate holder for holding and transporting the sample plate in the liquid scintillation counter. The holder includes a device to hold sample plates of different sizes and a device to enable transportation of the sample plate in the liquid scintillation counter.

Abstract: A method for producing standardization samples (11, 21) for obtaining the quench curve which describes the relationship between the counting efficiency and the amount of the quench of the sample is described. According to this method the different quench levels of the standardization samples are performed by covering different standardization samples with scintillation photons permeable foils (12, 13, 14, 25) having variable amounts of black dots (22, 23, 24), which absorb of produced scintillation photons.

Abstract: Apparatus for measuring the .alpha. activity of a solution and used for determining the plutonium concentration of a solution sampled from an irradiated nuclear fuel reprocessing installation and which comprises a rotary drum (20), which samples a film of solution in a vessel (20), in order to place it in front of a measuring probe (22). Between the probe (22) and the drum (20) is positioned a sealing disk (40) having three positions, which has an effective measuring region (48), a measuring chain quality checking region and a blank measuring region. In order to avoid a solution deposit by condensation on the disk (40) or on the end of the probe (22), a protective gas injection system (49) having passages traversing the vessel cover (16), scavenges the upper face of the sealing disk at three locations corresponding to the three active regions of the latter. A substantially uniform distribution of the gas flow between said three locations is ensured. The protective gas is then sucked in by a tube (122).

Abstract: A method for filtration assaying a particulate sample labelled with low-energy radioactive isotopes measurable by scintillation counting. The method aspect of the invention includes the step of providing a sample comprising sample particles labelled with low-energy radioactive isotopes in a liquid medium. Scintillant particles are added to the liquid medium. The sample is then filtered with a filter medium adapted to retain the sample particles and the particles of scintillant, such that after filtration the sample particles are each surrounded by scintillant. A photodetector is then used to detect light emitted by the scintillant on the filter medium.

Abstract: A method and apparatus for detecting the line of flight, point of entry and angle of entry of an energetic, ionizing particle uses a helical array of scintillating optical fibers.

Abstract: A continuous air monitor is provided with the capabilities of monitoring certain transuranic and other airborne radioactive particulate with high accuracy and low false alarm rates in the presence of radon and thoron daughter products. A multiple filter sampling approach is used wherein air flow is directed on a alternating basis to each sampling filter in turn. Each filter collects particulate in the size range of interest. Beta and/or alpha activity can be continuously measured on each filter. The air flow can be directed through a chamber where radon and/or thoron gas portions of the air may decay into their daughters and the quantities thereof may be separately measured.

Abstract: Disclosed herein is a radiation detector providing for the in situ automatic sampling of fluids containing substances emitting radiation, especially Cerenkov radiation. The detector permits sampling within well casings and is self-purging such that no additional provisions must be established for the storage and disposal of contaminated fluids.

Abstract: A method for correcting measuring values when measuring liquid scintillation samples deposited on sample plates by a photodetector which will be affected by scintillation photons from other samples in the plate in addition to the sample being measured. Said correction is done by pre-determining affection of the other samples of the plate as a function of quench level and correcting observed measuring values using this function.

Abstract: "A method for liquid scintillation counting of the radioactive nuclides of the natural decay chains of Th-232, U-238 and U-235 by detecting decay events of the short-lived members Po-212, Po-214 and Po-215 of these decay chains by the principle of delayed coincidence, characterized in that a separate pulse height spectrum is recorded for those pulses of the counting device which occur within a fixed short time interval after a preceding pulse. The successive decays cause pairs of quickly succeeding pulses to be detected; the coincidence of these pulses within a brief time interval makes it possible to distinguish the decay events from other decay events. The invention further permits simultaneous counting of different isotopes by fixing several short time intervals following a first pulse, and assigning a second pulse following the first pulse to one of several separate pulse height spectra in accordance with the length of the time interval within which the second pulse occurs.

Abstract: A method for performing liquid scintillation counting by the liquid scintillation counter that measures radioactive samples on a measurement support, such as a filter plate or alike, which has the sample associated therein. According to the method, the detection material, such as scintillator, is added to the measurement support before the measurement. The method according to the invention is characterized by adding detection material, such as scintillator, in melted form into the measurement support and performing the measurement after the detection material has solidified. On the filter plate is added for instance a mixture of paraffin and scintillator. One component in the detection material can be plastic scintillator.

Abstract: A system for in-situ measurement of the radioactivity of multiple samples while the samples are in a multiple-well sample tray, with a scintillator in each sample-containing well for producing light pulses in response to radiation from the respective samples. Multiple photomultiplier tubes are positioned adjacent to the sample wells containing the scintillator for simultaneously measuring the radioactivity of multiple samples with only a single photomultiplier tube sensing the scintillations from each well and converting the sensed scintillations into corresponding electrical pulses. The electrical pulses from each photomultiplier tube are processed to discriminate between pulses attributable to sample events within the wells and pulses attributable to non-sample events such as photomultipler tube noise.

Abstract: The object of the invention is a method for the evaluation of sample activities in multidetector liquid scintillation counters. According to the invention the memory of said apparatus is provided with a theoretically derived model for each isotope between the counting efficiencies and the quench levels. In addition at least one standard is measured in each detector in order to establish relationships between said theoretical model and each detector. The activities of an unknown sample is evaluated by utilizing said theoretical model and said relationship.

Abstract: A method for correction of the counting error in liquid scintillation counting in the attenuation of light passing through a sample solution is measured before or after the actual liquid scintillation counting takes place. By means of the attenuation measurement the error in the liquid scintillation counting result, caused by the colorness of the sample solution, and/or by the counting apparatus, is corrected. The apparatus has a liquid scintillation counter provided with cylinder shaped optics. A photometer is incorporated in the liquid scintillation counter. By means of the photometer, the attenuation of light passing through the sample solution is measured before or after the actual liquid scintillation counting measurement, where said attenuation is caused by the colorness of the sample solution and/or due to features of the apparatus.

Abstract: The counting error due to variations in the counting efficiency as a function of the volume of the sample is corrected. The sample is placed into a sample container which is placed into a vertically positioned cylinder shaped counting chamber. Photomultiplier tubes are disposed on the opposite ends of the counting chamber. At least two of the following spectra are measured in the coincidence counting: the sum spectrum q observed by both of the photomultiplier tubes, the spectrum q(y) observed by the upper photomultiplier tube and the spectrum q(a) observed by the lower photomultiplier tube. The counting error is corrected by the correction coefficient obtained from these spectra.

Abstract: The present invention is a scintillator which emits light in response to radiation. The scintillator is capable of being reversibly changed between solid and liquid phases, whichever is desired, by temperature control. The scintillator comprises a fluorescent substance for converting radiation energy into light energy; a solvent which transfers radiation energy to the fluorescent substance and dissolves and diffuses the fluorescent substance and a radioactive substance acting as an object of measurement to thereby homogenize them; and a fixing substance which enables the solvent, the fluorescent substance and the radioactive substance to be fixed in a solid state and also liquified upon heating, the fixing substance being capable of phase change reversibility.

Abstract: A low-level liquid scintillation measurement system for counting sample optical events resulting from the radioactive decay of a constituent of a sample to be measured while reducing the counting of background optical events which are optical events produced by background radiation and which create electrical pulses other than pulses representing a sample optical event.

Abstract: A device for simultaneously measuring the level of particle and quantum radiation of a plurality of samples which includes a microplate having a plurality of wells for accommodating the plurality of samples. A plurality of light conductors, at least one for each well, is positioned to receive light from each well and forward it to a photodetector. When luminescence is determined, each well has only one conductor associated therewith and when liquid scintillation is determined, each well has two light conductors associated therewith.

Abstract: A device and method for measuring properties of certain substances such as analytes are provided. The device includes a probe housing having an optical fiber associated therewith. The housing is capped on one end by a porous membrane which is permeable to the analyte being studied. The housing also includes a reflective surface member disposed between the end of the optical fiber and the membrane, thereby defining a chamber. The reflective surface member does not allow light to be transmitted into or out of the chamber. However, a dye-labeled analog-analyte can permeate the reflective surface member and thereby allow a measurement to be taken which is related to the concentration of the analyte being studied. An embodiment for use in vivo is provided. A related method is also provided.

Abstract: Liquid scintillation counter includes a memory having stored spectra of known counting efficiencies and known levels of quench, for the isotopes to be meansured. A device extracts from the spectra, using the determined quench level value for each of the N isotopes, a reference spectrum representing a pure isotope spectrum at the determined quench level. A device determines for each extracted reference spectrum a factor by which the extracted reference spectrum is to be multiplied in order to fit the sum of the multiplied reference spectra to the sample spectrum. Each factor is directly related to the amount of each isotope in the sample.

Abstract: Liquid scintillation counter includes a memory having stored spectra of known counting efficiencies and known levels of quench, for isotopes to be measured. A device extracts from the spectra, by using the determined quench level value for each of the N isotopes, a reference spectrum representing a pure isotope spectrum at the predicted quench level. A device determines for each extracted reference spectrum a factor by which the extracted reference spectrum is to be multiplied in order to fit the sum of the multiplied reference spectra to the sample spectrum. Each factor is directly related to the amount of each isotope in the sample. A device computes a goodness-of-fit value and predicts a new value for the quench level based on this goodness-of-fit value. A method in liquid scintillation counter includes predicting a first value of the quench level of the scintillation sample.

Abstract: Prior art methods for quantitation of radioisotopically labeled molecules employ isotopes emitting a single electron, positron or gamma-photon. Their sensitivity is limited by background events which cannot be distinguished from the decays of the isotopic label. There are isotopes decaying with concurrent production of a positron and a gamma photon, with a subsequent positron-electron annihilation producing paired 511 keV gammas with opposite momenta. The Coincident Gamma-photon Detector (CGD) registers a count when coincident gamma-photons of known energies are detected. When set to the triple gamma signature of a particular isotope, the CGD achieves exceptional background rejection with resultant improved capacities to quantitate minute traces of the isotope. With the increased sensitivity thus achieved, there are advantageous novel uses of the multiple gamma producing isotopes, for the quantitation of molecules in which they can be incorporating or adducted to.

Abstract: An arrangement for improving the counting of liquid scintillation samples including a plurality of separate sample wells, a plate holder surrounding the sides of each sample well so that each plate holder forms an optically separate compartment for each sample well, at least one photomultiplier tube adjacent each sample well, and a coating of light reflective or light scattering material on the inner surfaces of said plate holders.

Abstract: An apparatus for counting liquid scintillation samples which includes a sample plate containing a plurality of cup-shaped sample wells, a photomultiplier assembly over the tops of said cup-shaped sample wells, a photomultiplier assembly beneath the bottoms of said cup-shaped sample wells and light reflective tubes extending upwardly from said lower photomultiplier assembly and surrounding each cup-shaped sample well.

Abstract: Determining whether a liquid scintillation sample is single- or multi-phase includes transforming all or a portion of a Compton Spectrum of data into different namely integrated, geometric space. A predetermined parameter in the selected geometric space, indicative of the phase content of the sample is selected, and compared with the data in the different geometric space. This provides a determination of the phase content of the sample. The linearity of the data indicates the phase content.

Abstract: A noninvasive pulsed fluorescence gas velocimeter that determines dynamic parameters of a gas flow from detection of fluorescent re-radiation of excited molecules of the gas. The present invention has higher altitude capability than devices that utilize particulate scattering. The velocimeter requires no probes and utilizes a laser or other light source that does not perturb the gas flow being measured.

Abstract: Monitoring and measuring colored samples by the techniques of liquid scintillation counting employs the relationship of absorbance and counting efficiency. A determination of whether color quench correction is required is made. Should a color monitor detect a color intensity which requires color correction, then efficiency correction is performed here. Both the color monitor and the color correction of efficiency are incorporated into a liquid scintillation counter which performs color monitoring, measurement and correction automatically.

Abstract: An apparatus for detecting radioisotopes in fluids (e.g., in gas/liquid chromatography) comprises a bundle of scintillating optical fibres 12 extending along the interior of a conduit 10 through which a fluid may flow. The bundle of scintillating optical fibres has ends 14, 16 passing through the side of the conduit 10 to connect with light detecting means 18, 20. Other embodiments and methods of use are disclosed.

Abstract: A carrier for at least on beta-particle-emitting sample to be measured in a scintillation counter comprises a sorption sheet on which the sample is to be deposited, a transparent bag within which the sorption sheet with the sample is to be contained, and a scintillant to be contacted with the sample within said bag. According to the invention the scintillant is a meltable solid scintillant which is coated onto at least part of the sorption sheet and/or the inside of the transparent bag, and which is to be melted to envelop and permeate the sample before measurement thereof.

Abstract: A method of detecting radioactive substance in a liquid sample which comprises steps of:(1) supplying a radiation-measuring instrument containing a stimulable phosphor with the liquid sample continuously or intermittently;(2) keeping said measuring instrument in contact with the liquid sample for a given period of time to cause the instrument to absorb at least a portion of radiation energy emitted by the radioactive substance in said liquid sample; and(3) irradiating said measuring instrument with an electromagnetic wave to release the radiation energy stored in the instrument as stimulated emission, and photoelectrically detecting the stimulated emission to measure radioactivity of said liquid sample sequentially.The method is particularly useful when employed in conjunction with liquid chromatography.

Abstract: A spectrometer for MEV neutrons relies upon total energy absorption to measure neutron energy. Neutrons are thermalized in a liquid scintillator-moderator providing a first light pulse and are subsequently captured in a Li-6 glass scintillator providing a second light pulse. The light pulses are converted into first and second electronic signals by photomultipliers. A coincidence signal is required from the neutron capture prior to gating electronic circuitry for measuring the amplitude of the first electronic signal. The dual signal from a single neutron provides a mechanism for discrimination against background events arising either from gamma rays or from ambient, low-energy neutrons. The spectrometer is particularly useful in situations in which the neutron source intensity is very low.

Abstract: A solution which increases the efficiency of radon extraction from either dry or moist charcoal samples is disclosed. The addition of low molecular weight organic solvents such as methanol or ethanol to liquid scintillation counting solution increases radon extraction from 20-500% over known counting solutions. The increased efficiency appears to occur from increased penetration of the charcoal by the low molecular weight solvent which dissolves the radon gas and the subsequent diffusion of the low molecular weight solvent out of the charcoal and into the liquid scintillation counting solution.

Abstract: Detection and quantitative measurement of the radioactive isotope of .sup.222 Rn, as encountered in air in habitats is accomplished in a passive detection system in which the radon at the test site is adsorbed into an adsorbent, e.g. activated charcoal, held in a vial made especially for liquid scintillation counting, and the radon is subsequently desorbed into a liquid scintillation desorbent placed in the same vial and the counting of the radon activity in the vial is accomplished by liquid scintillation techniques.

Abstract: In a liquid scintillation counter the light output from a liquid scintillation sample containing radioactive isotopes of unknown activity is measured by means of a detector. A pulse height analyzer having discriminators that are combined to define pulse height windows, is connected to the detector for measuring and temporarily storing count rates for each of the windows. Moreover, there are means for determining a value for the quench level of the sample. According to the invention the number of pulse height windows is at least N+1, when the number of isotopes is N,N being .gtoreq.2. There are memory means for storing for each of said windows representations of counting intensities determined by measuring calibration samples of each isotope at different levels of quench.

Abstract: A sample counting support for scintillation counting of a radioactive labeled sample comprises a base material covered with a thin layer of dry solid scintillator in a substantially permanent form so that the support may receive the sample and produce light emissions in response to particules emitted by a radioactive substance labelling said sample.

Abstract: This invention is a technique to determine radioactivity of low energy beta emitters using liquid scintillator. Corrections for regression equations which represent the relationship between counting efficiency of a standard and counting rate of a sample make it possible to obtain the radioactivity of the low energy beta emitters. It is very difficult for the emitters to be measured with the conventional efficiency tracing technique.

Abstract: A sheet-form radiation-measuring instrument for measuring radioactivity of a liquid sample, having a liquid-retaining member capable of retaining a liquid sample containing a radioactive substance, a transparent protective film of synthetic polymer material and a stimulable phosphor member containing a stimulable phosphor therein. The instrument may be in an integrate structure or a separate structure.