Liquid scintillation counting (LSC) techniques can be used for radionuclide standardization when the calculation of detection efficiency is possible. This is done using a model of the physicochemical processes involved in light emission and also of the statistics of photon emission: the free parameter model. This model can then be applied in two ways: by deducing the free parameter from the measurement of a tracer (the CIEMAT/NIST method) or by calculating this free parameter from coincidence ratio in a specific LS counter (the TDCR method). The purpose of this paper is to describe both these models and some practical issues that need to be addressed if LSC is to be effectively used in radionuclide metrology.

https://iopscience.iop.org/article/10.1088/0026-1394/44/4/S06/pdf

Radionuclide metrology using liquid scintillation counting

The fluorescence quantum yield Φ f is a key property that characterizes the ability of a fluorophore to convert absorbed photons into emitted photons under various environmental conditions. Knowledge of it is important for the successful development of fluorometric indication and visualization methods and for the understanding of light-driven processes in the natural sciences. Φ f is a molecule- or material-related parameter and can thus significantly differ from the fraction of absorbed photons that are actually measured as the fluorescence signal of a certain sample, e.g., when the signal is modulated by reabsorption, self-quenching or polarization effects. The determination of Φ f can be performed in absolute measurements or relative to a fluorescent standard material with a known Φ f by optical or calorimetric methods. Here the different procedures and techniques are described and compared, and the suitability of a representative number of dyes that have been proposed as fluorescence reference materials in the past 25 years is discussed. Besides addressing specific issues such as low-temperature measurements and the appropriate choice of standards and measurement conditions, we conclude with recommendations for better standardization and quality management in this area.

Fluorescence Quantum Yields: Methods of Determination and Standards

Advances in technologies for the measurement of uranium in diverse matrices

Separation and measurement of thorium, plutonium, americium, uranium and strontium in environmental matrices

We review developments in radiocarbon measuring techniques from the Libby counter through proportional gas counters and liquid scintillation spectrometers to the more recent developments of accelerator mass spectrometry (AMS), followed by a coupling of gas chromatography with AMS for compound-specific 14C analyses. While during the first 60 yr of 14C measurements beta counting, specifically gas counting, was the dominant technique, in the future of 14C science AMS will be the dominant technology.

/pdf/developments-in-radiocarbon-technologies-from-the-libby-1c64m0xi7b.pdf

Developments in radiocarbon technologies: from the libby counter to compound-specific ams analyses

PME, A Model Scintillation Salute with a Large Stokes' Shift. Scintillation Counting of Harvested Biological Samples with Low Energy Beta Emitters Using Solid Scintillant Filters. Di-isopropylnaphthalene-A New Solvent for Liquid Scintillation Counting. Safe Scintillation Chemicals for High Efficiency, High Throughout Counting. New Organic Scintillators. Advances in Scintillation Cocktails. Solidifying Scintillators for Solid Support Samples. New Red-emitting Liquid Scintillator with Decay Times Near One Nanosecond. New Developments in X-Ray Sensitive Liquid Scintillators Act Egg/em*. Liquid Scintillation Alpha Spectrometry: A Method for Today and Tomorrow. Application of High Purity Synthetic Quartz Vials to Liquid Scintillation Low Level 14C Counting of Benzene. An Introduction to Flat-bed ISC: The One Word Beta Plate Counter. A New, Rapid Analysis Technique for Quantitation of Radioactive Samples Isolated on a Solid Support. Dynodic Efficiency of Beta Emitters. Solid Scintillation Counting: A New Technique-Theory and Applications. Photon Scattering Effects in Heterogeneous Scintillator Systems. Some Factors Affecting Alpha Particle Detection in Liquid Scintillation Spectrometry. Modern Techniques for Quench Correction and DPM Determination in Windowless Liquid Scintillation Counting: A Critical Review. Multi-label Counting Using Digital Overlay Technique. A New Quench Curve Fitting Procedure: Fine-tuning of a Spectrum Library. The Effect on Quench Curve Shape of the Solvent and Quencher in a Liquid Scintillator Counter. Modem Applications in Liquid Scintillation Counting. A New Procedure for Multiple Isotope Analysis in Liquid Scintillation Counting. The Standardization of Beta-gamma Emitting Nuclides by Liquid Scintillation Counting. The Standardization of Sulphur-35 Methionine by Liquid-Scintillation Efficiency Tracing with Hydrogen-3. A Review and Experimental Evaluation of Commercial Radiocarbon Dating Software. Efficiency Extrapolation Adapted to Liquid Scintillation Counters. Applications of Quench Monitoring Using Transformed External Standard Spectrum (tSIE). Scintillation Proximity Assay: Instrumentation Requirements and Performance. The ISC Approach to Radon Counting in Air and Water. Liquid Scintillation Screening Method for Isotopic Uranium in Drinking Water. Assessment and Assurance of the Quality in the Determination of Low of Tritium in Ground Water. Use of Liquid Scintillation in the Appraisal of Nonradioactive Waste Shipments from Nuclear Facilities. Development of Aqueous Tritium Effluent Monitor. Rapid Termination of PU Content on Filters and Smears Using Alpha Liquid Scintillation. Vagaries of Wife Testing Data. The Determination of 234TH in Water Column Studies by Liquid Scintillation Counting. Performance of Small Quartz Vials in a Low Level, High Resolution Liquid Scintillation Spectrometer. The Optimization of Scintillation Counters Employing Burst Counting Circuitry. Statistical Considerations of Very Low Background Countrates in Liquid Scintillation Spectrometry with Applications to Radiocarbon Dating. Liquid Scintillation Counting Performance Using Glass Vials in the Wallac 1,220 Quantulus(TM). Time Resolved Liquid Scintillation Counting. Comparison of Various Anticoincident Shields in Liquid Scintillation Counters. The Effect of Altitude on the Background of Low Level Liquid Scintillation Counter. Calculational Method for the Resolution of Strontium-90/Strontium-89 Counts from Cerenkov and Liquid Scintillation Counting. Determination of RN-222 and RA-226 in Drinking Water by Low Level Liquid Scintillation Counting-Surveys in Austria and Arizona. A New Simplified Determination Method for Environmental SR-90 by Ultra Low Level Liquid Scintillation Counting. Mixed Waste-A Review from a Generator's Perspective. Disposal of Scintillation Cocktails. Liquid Scintillation Waste. Liquid Scintillation Counting of Radon and Its Daughters. LSC Standardization of P-32 in Inorganic and Organic Samples by the Efficiency Tracing Method. ANSI Standards for Liquid Scintillation Counting. A General Method for Determining Sample Efficiencies in Liquid Scintillation Counting. Absolute Activity Liquid Scintillation Counting: An Attractive Alternative to Quench-Corrected DPM for Higher Energy Isotopes. Chemical and Color Quench Curves Over Extended Quench Ranges. The Characteristics of the CH Number Method in Liquid Scintillation Counting. Low Level Scintillation Counting With a LKB Quantulus Counter. 600 pp.

Harley Ross

Papers

Liquid Scintillation Counting and Organic Scintillators