Wallac Oy

Wallace Oy

Tapio Yrjonen

Kauko Lehtinen

Timo E Oikari

Vesa Sonne

Heikki K Kouru

Stefan Jarnstrom

Tuula Stark

Markku Varjonen

Jan Ostrup

Jan Strup

Urpo Pietila

Tim Rawlins

Stuart Webb

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.

Apparatus for counting liquid scintillation samples

A method for the evaluation of sample activities in multidetector liquid scintillation counters. All prepared quench curve standards are measured only in one reference detector in order to establish the relationship between the quench levels and the counting efficiencies. In addition, only two of the standards, preferably those with lowest and highest level of quench, are measured in every detector in order to establish the relationship of the quench levels between the reference detector and any other detector and in order to establish the relationship of the counting efficiencies between the reference detector and any other detector. The activities of unknown samples are evaluated by utilizing the predetermined relationships.

Method for evaluating sample activities in a multidetector liquid

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).

Method for measuring samples with liquid scintillation counting and a

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.

Method and a device for preventing optical crosstalk between liquid

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 information.

Method for measuring liquid scintillation samples deposited on

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. In cases where the samples on the sample plate are measured from the top by a single photomultiplier tube the foil is reflective to reflect scintillation light to the photomultiplier tube. In cases where the samples on the sample plate are measured from the bottom by a single photomultiplier tube a reflective adhesive foil is attached to the top of the sample plate to reflect scintillation light to the photomultiplier tube.

Arrangement for counting liquid scintillation samples on bottom-window

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.

Arrangement for counting liquid scintillation samples on multi-well

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.

Method for correcting measuring values when measuring liquid

Method for performing liquid scintillation counting and detection

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.

The present invention provides a scintillation counter that includes a measuring chamber accommodated to take the sample and viewed by two photodetectors, preferably photomultipliers, that can be operated in coincidence. Associated with the chamber is an additional scintillator, preferably an inorganic crystal scintillator, optically isolated from the chamber by a light-permeable wall and mounted so that the scintillation light generated in the additional scintillator is guided predominantly only to one of the two photodetectors. A comparator is used for registering pulse amplitude disparity between the photodetectors to distinguish low-disparity, sample generated pulses and high-disparity, additional scintillator generated pulses.

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Turku, Finland

Tapio Yrjonen