A comparison of two methods used for determination of tritium concentration in urine samples by liquid scintillation counter

Background Tritium(3H)emits low-energy beta particles with a maximum energy of 18.6 keV.Liquid scintillation counting technique(LSC)is mostly used for the detection and quantification of low-energy emitters like H-3.The most widely used method to determine the level of tritium in humans is testing urine.Method In this study,tritium activity concentrations in urine samples taken from 20 adults were measured.Their ages range from 23 to 50.Eight of them are female,and others are male.The tritium activity concentrations in urine samples were determined with two different methods.Also,two standard samples were used to compare urine samples.Result The efficiency values were found with two different methods(26.07%for the first method and 26.14%for the second method).According to the comparison results,the tritium concentration differences between these methods were found in a negligible level for urine samples and in an acceptable level for standard samples.Conclusion The tritium activity concentrations in urine and standard samples were calculated using two different methods.According to the comparison results,these two methods can be used for determination of tritium concentrations in urine samples.

Standardization of Tritium Water by TDCR Method

The triple-to-double coincidence ratio （TDCR） method of liquid scintillation count- ing is an absolute measurement method of radioactivity. The formulation of the TDCR method and the established TDCR liquid scintillation counter are presented in this paper. The NIST standard reference material （SRM） of tritium water was measured to verify the performance of the TDCR liquid scintillation counter.

Determination of Radon Content in Water Respecting to Directive of Council 2013/51/EURATOM

In accordance with the recommendations of the most recent Directive of Council EURATOM No. 2013/51, which concerns requirements for the protection of the health of the general public with regard to radioactive substances in water intended for human consumption, we are obligated to monitor the level of approximate dose of radioactive substances. The directive indicates two basic isotopes: tritium and radon, which ought to be monitored continuously. Essential are also para-metric values as well as frequency, methods of monitoring of radioactive substances and equipment requirements. Directive states that measurements of content of tritium and radon ought to be taken as well as calculations of approximate dose natural and artificial radionuclides content should be done, apart from tritium, potassium-40, radon and short-living products of radon disintegration. In case if one of radioactive concentrations is over 20% of computational value or concentration of tritium is over parametric value analysis of additional radionuclides is required. A detailed list of radionuclides is presented in appendix No. 3 in the Directive. Laboratory of Nuclear Control Systems and Methods in the Institute of Nuclear Chemistry and Technology (INCT) worked out a Miniature Liquid Scintillation Counter (LCS) [1] [2], within a project titled “New generation of intelligent radiometric devices with cordless transmission of information” (UDA-POIG.01.03.01-14-065/08) co-financed by European Union from the European Regional Development Fund (ERDF). This Miniature Liquid Scintillation Counter may be used as a basic equipment resulting in the above mentioned directive. This article presents results of conducted research based on LCS and comparison of this results with the measurements carried out by Accredited Laboratory for Cali-bration of Dosimetric and Radon Instruments in Central Laboratory for Radiological Protection in Warsaw (CLOR).

A study of time over threshold (TOT) technique for plastic scintillator counter

A new charge measurement method, time over threshold （TOT）, has been used in some gas detectors lately. HereTOT is studied for TOF system, made of plastic scintillator counter, which can simplify the electronics of the system. The signal characteristics are measured and analyzed with a high quality oscilloscope, including noise, pedestal, signal amplitude, total charge, rise time and the correlation between them. The TOT and charge are related and can be fitted by some empirical formula. The charge measurement resolution by TOT is given and this will help the design of TOF electronics.

Method for improving the time resolution of a TOF system

In order to study the possibility of improving the timing performance of the time of flight （TOF） systems, which are made of plastic scintillator counters, and read out by photomultiplier tubes （PMT） with mesh dynodes and conventional electronics, we have conducted a study using faster PMTs and ultra fast waveform digitizers to read out the plastic scintillators. Different waveform analysis methods are used to calculate the time resolution of such a system. Results are compared with the conventional discriminating method based on a threshold and pulse height. Our tests and analysis show that significant timing performance improvements can be achieved by using this new system.