Scintillation counting system for in-situ measurement of radioactive samples in a multiple-well plate
First Claim
1. A method for in-situ measurement of the radioactivity of multiple beta-emitting samples while the samples are in a multiple-well sample tray in which each well is open at its upper end, said method comprisingproviding a scintillator in the lower portion of each sample-containing well where the scintillator is directly exposed to the beta emissions from the respective samples for producing light pulses in response to said beta emissions,positioning multiple photomultiplier tubes adjacent to the open upper ends of said sample wells containing said 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 face of each photomultiplier tube covering substantially the entire open upper end of the corresponding sample well,processing the electrical pulses from each photomultiplier tube to discriminate between pulses attributable to sample events within said wells and pulses attributable to non-sample events such as photomultiplier tube noise, said discrimination being effected by determining whether a selected number of electrical pulses occurs within a prescribed time interval, the occurrence of said selected number of pulses within said prescribed time interval signifying a sample event, andsupplying only the electrical pulses attributable to sample events to a pulse analyzer.
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Accused Products
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. The discrimination is effected by determining whether a selected number of electrical pulses occurs within a prescribed time interval, the occurrence of the selected number of pulses within the prescribed time interval signifying a sample event. Only the electrical pulses attributable to sample events are supplied to a pulse analyzer.
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Citations
16 Claims
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1. A method for in-situ measurement of the radioactivity of multiple beta-emitting samples while the samples are in a multiple-well sample tray in which each well is open at its upper end, said method comprising
providing a scintillator in the lower portion of each sample-containing well where the scintillator is directly exposed to the beta emissions from the respective samples for producing light pulses in response to said beta emissions, positioning multiple photomultiplier tubes adjacent to the open upper ends of said sample wells containing said 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 face of each photomultiplier tube covering substantially the entire open upper end of the corresponding sample well, processing the electrical pulses from each photomultiplier tube to discriminate between pulses attributable to sample events within said wells and pulses attributable to non-sample events such as photomultiplier tube noise, said discrimination being effected by determining whether a selected number of electrical pulses occurs within a prescribed time interval, the occurrence of said selected number of pulses within said prescribed time interval signifying a sample event, and supplying only the electrical pulses attributable to sample events to a pulse analyzer.
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9. A scintillation counting system for simultaneously measuring the radioactivity of multiple radioactive samples, said system comprising
a sample tray forming multiple sample wells arranged in an array of x columns and y rows, each of said wells being open at its upper end, a scintillator in each sample well for making direct contact with a sample placed therein and producing light pulses in response to radiation from said sample, multiple photomultiplier tubes ("PMTs") arranged in a matrix such that each PMT is aligned with a different one of said sample wells adjacent the open upper ends of the wells, and each sample well has only one PMT aligned with it, for converting the light pulses from the scintillators in the respective wells into corresponding electrical pulses, the face of each photomultiplier tube covering the entire area of the open upper end of the corresponding sample well, electronic signal processing means receiving said electrical pulses from said PMTs and determining whether a selected number of electrical pulses occurs within a prescribed time interval, the occurrence of said selected number of pulses within said prescribed time interval signifying a sample event, and a pulse analyzer receiving only the electrical pulses attributed to sample events.
Specification