LSC – Laboratory for Liquid Scintillation Spectrometry

Jožef Stefan Institute
Jamova 39
SI-1000 Ljubljana
Slovenia

T:+38614773970, +38614773264, +38614773841

Leader: Dr Jasmina Kožar LogarCoworkers: Klara Poiškruh, Dr Romana Krištof

Activities

Acredited measurements according to ISO 17 025– determination of tritium (H-3), radiocarbon (C-14), gross alpha and beta activity:

Environmental samples (Off-site Radiological Monitoring of Krško Nuclear Power Plant, Survey of Radioactivity in the Environment in the Republic of Slovenia, Survey of Radioactivity in the vicinity of Uranium mine Žirovski vrh and repository of radiactive vaste in Brinje),
Tap and bottled water (study of radiologic exposure of the population),
Thermal and other groundwater (datirng, hydrology studies, vulnerability estimations),
Food ans bottled water (authority's needs, import and export controls),
Coatings, resins, chemicals, fuels, etc. (determination of bio-origin),
urine (survey of workers in nuclear industry).

Development and implementation of new analytical methods for radioactivity measurements by Liquid scitnillation spectrometry:

tritium in water and urine – different methods that vary in sample preparation and sensitivity,
tissue free water tritium (TFWTj and organically bond tritium (OBT) in biological samples,
radiocarbon in liquids, gases and solids,
gross alpha and beta activity in water samples,
characterization of rapid method of IAEA for determination of Ra-226 and Ra-228 in water samples.

Education and trainings:

gaining experience in an accrtedited laboratory for sudents of all llevles of education,
organization of working practice for Slovenian and foreign sudents,
mentorstvo pri diplomskih, magistrskih in doktorskih nalog za domače in tuje študente in univerze,
mentoring in B.Sc, M.Sc and Ph.D theses for Slovenian and foreign students and Universities,
visits of foreign university professors,
conducting of workshops for adminitration, authorities, public service providers, concessionaires, companies,
invited lectures at international workshops, universities, organizations, companies.

Preparation, characterization and testing of reference materials and intercomparison samples in cooperation with following institutions:

ARPA Lombardia, Italy,
IARMA, Scotland,
IAEA.

Research and Development Activity, expert studies:

Applicative and fundamental national and international research projects,
Industrial projects – method development, measurements of specific samples, evaluation of results,
Environmental and radiological studies for authorities and administration,
Evaluation of environmental monitorings, ekspertises for international organizations IAEA),
Design of specific equipment for in –house analyrical methods.

Methods

Tritium in water

Two methods are performed for determination of tritium in water samples (direct and electrolytic enrichment method).

Sample preparation: After distillation, pH and conductivity are checked. In the direct method, a scintillation cocktail is added to the distillate. Sodium peroxide is added to the distillate in the frame of electrolytic enrichment method. Half a liter of the sample is electrolytically enriched. After pre-concentration of the sample by electrolysis, lead chloride is added and a second distillation is carried out. A scintillator cocktail is added to the distilled sample with appropriate pH value.

Measurement: in Liquid Scintillation Counter Quantulus 1220 (Wallac, PerkinElmer). Certified standard solutions are used for counter calibration and quench curve preparation.

Tritium in urine

There are three different procedures of sample preparation (direct, distillation and neutralization method).

Sample preparation: Scintilation coctail is added to the sample in the frame of direct method. The steps within distillation method are: distillation, determination of pH value and repetition of distillation if necessary, addition of scintillation cocktail. Neutralization is performed by hydrogen peroxide. Scintillation cocktail is added to discolorated sample

Measurement:. in Liquid Scintillation Counter Quantulus 1220 (Wallac, PerkinElmer). Certified standard solutions are used for counter calibration, quench curve preparation and standard addition method.

Tissue Free Water Tritium (TFWT)

Two procedures are available for sample preparation (lyophilisation and azeothropic distillation).

Sample preparation: Fresh and clean sample is cut into small pieces. The water is acquired by azeotrophic distillation or lyophilisation. Scintillation cocktail is added to the sample with proper pH..

Measurement: in Liquid Scintillation Counter Quantulus 1220 (Wallac, PerkinElmer). Certified standard solutions are used for counter calibration, quench curve preparation and standard addition method.

Organically Bound Tritium (OBT)

Sample preparation: Dried and ground sample is combusted. CO2 after complete oxidation can be used for C-14 analysis., but the combusted water is lyophilized after neutralization by sodium peroxide and potassium permanganate. PH value is checked and lyophilisation is repeated if necessary. So treated sample is mixed with scintillation cocktail.

Bio-origin in fuels, coatings, resins and other liquid samples – direct method

Sample preparation: Appropriate scintillation cocktail is added to weighed sample in optimized ratio.

C-14 in liquid, gaseous and solid materials – absorption method

Sample preparation: Carbon within dried sample is transformed to CO2 by combustion or appropriate chemical reaction. The gas is cleaned and cought into weighed and colled trap, filled by the liquid absorber. The quantity of captured CO2 is determined by weighing. The final step of sample preparation is addition od scintilation cockatil.

Total activity of alpha and beta emitters in water / gross alpha and beta emitters (GAB method)

Samples can be prepared on two different ways, using direct method or pre-concentration.

Sample preparation: Samples are acidified to aprropriate pH value and mixed with scintillation cocktail. Pre-concentration is reached by evaporation of acidified samples at stable temperature. Scintillation cocktail is added to the sample with appropriate pH when cooled to the room temperature.

Measurement: in Liquid Scintillation Counter Quantulus 1220 (Wallac, PerkinElmer).Pair of certified standard solutions are used for counter calibration and determination of windows.

Other Projects and Programmes

Programmes:

Hadron Systems Structure

International Projects

(2010 – 2011) BI-HR/10-11-009: Measurement of tritium activity in natural waters using electrolytic enrichment
(2010 – 2014) BC 381. 170. 10010. H1060731: Repeatability and reproducibility testing of a procedure for the rapid determination of Ra-226 and Ra-228 in water by liquid scintillation counting, pilot study in the frame of IAEA
(2005 – 2010) RER-7003-9008: Marine Environmental Assessment of the Mediterranean Sea (RER-7003-9008);
(2012 – 2013) BI-RO/12-13-016: LSC methods for determination of H-3 and C-14 in environmental samples; bilateral cooperation with Romania, 2012 – 2013
(2017) Elaboration of medium term strategy of the IAEA in reference material production and proficiency test organization
(2013 – nowadays) Preparation and characterization of reference materials and intercomparison samples

National Projects

(2005 – 2008) L1-7035-0106: Dating of Waters by H-3 and Pb-210: groundwater Dynamics and Vulnerability of Deep Aquifers
(2006 – 2008) V1-0293: Age, origin and dynamics of waters of deep aquifers of Ljubljansko Barje
(2006 – 2008) V2-0379: Tracking of tritium along Sava river and in the environment of Nuclear Power Plant Krško
(2006 – nowadays) Off-site radiological monitoring of Krško Nuclear Power Plant, Slovenia
(2008 – 2011) L1-0347: Natural hydro-chemical backgrounds and dynamics of Slovenian ground waters
(2008 – 2011) J7-0363: Natural and anthropogenic gamma and beta emitters in groundwaters in Slovenia
(2008 – nowadays) Tritium in mineral and thermal waters of Slovenia
(2009 – 2010) N161300-09-0328: Development and validation of the method for determination of bio-origin in fuels
(2009 – novadays) Determination of bio-origin in fuels
(2010 – 2011) Tritium Analysis and interpretation of the results
(2011 – 2014) Groundwater age determination in deep aquifers of Slovenia
(2015) N4500105754: Radioactivity of mineral waters in the regulations around the World
(2015) C2717-15-232006: Tritium in tap waters of Slovenia
(2015 – 2019) C2717: Gross alpha / beta measurements in tap waters of Slovenia
(2017) AMIIGA - Tritium in groundwater around Ljubljana
(2017) Specific analysis on special sampling points
(2017 – 2020) Determination of bio origin in melamine resins and their input materials
(2018) Gross alpha / beta measurements on special sampling points – trends and values
(2020) Specific analysis on special sampling points

External coworkers

Mitja Centrih
Polona Gerjol
Urška Petrač
Nataša Čipanovska
Sonja Gabrijelčič
Matic Dokl
Polona Mertelj

Radioactivity is (above all) a natural phenomenon that can be used as a tool in medicine, geology, industrial processes and wherever. It can be a clock, a tracer of natural and other processes, therapy, energy. Some of these wonderful possibilities are also addressed by the Laboratory of Liquid Scintillation Spectrometry (LSC Laboratory), established in 2005 within the Infrastructure Group ISMIS of Department of Low and Medium Energy Physics at the Jožef Stefan Institute.

The results of the LSC Laboratory are useful for the control of natural and artificial radioactivity in the environment, such as in drinking water, rivers and agricultural crops. Special attention is paid to samples from the surroundings of nuclear facilities. Using radioactivity measurements, we can point out the degree of vulnerability of groundwater and estimate its resident time in aquifer. For fuels, lubricants, coatings, resins, oils, chemicals, we can tell whether and to what extent they are obtained from bio-components or renewable sources. By measuring the content of radionuclides, physiological processes, transport of nutrients and other substances in the soil, in the air, in individual cells, in complex organisms can be followed.

The LSC Laboratory provides accredited analyzes of radionuclide content, especially alpha and beta emitters (H-3, C-14, gross alpha and beta activity). The most common users of our services are Slovenian and foreign authorities, industry, scientific research groups and of course curious individuals. The LSC Laboratory develops and introduces new analytical methods, encourages their use in various fields, interprets the results and places them in a broader framework, educates society, community of experts and students at all levels of education. In the metrology field, we cooperate in the preparation of reference materials and interlaboratory tests.

The backbone of the LSC Laboratory are three liquid-scintillation counters that boast a high degree of stability and extremely low measurement backgrounds. This allows us to accurately measure the content of radioactive substances even in samples where radionuclides only appear in traces. Liquid scintillation spectrometry is based on the detection of photons evoked by radioactive decays in fluorescent substances that added to previously chemically treated samples.