SVIBOR - Project code: 1-07-064

MINISTRY OF SCIENCE AND TECHNOLOGY

Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69
E-mail: ured@znanost.hr

SVIBOR - Collecting Data on Projects in Croatia

Project code: 1-07-064

NATURAL ISOTOPES H-3, C-14, Th/U AND IONIZATION IN GASES

Main researcher: SRDOČ, DUŠAN (44284)

Assistants

OBELIĆ, BOGOMIL (33855)
HORVATINČIĆ, NADA (16101)
KRAJCAR-BRONIĆ, INES (112976)
SLIEPČEVIĆ, ADICA (43691)

Type of research: basic
Duration from: 01/01/91. to 12/31/95.

Papers on project (total): 77
Papers on project quoted in Current Contents: 21

Institution name: Institut "Ruđer Bošković", Zagreb (98)
Department/Institute: Department of Physics - Division for Experimental Physics
Address: 10001 Zagreb, P.p.1016, Bijenička 54
City: 10000 - Zagreb, Croatia

Communication: Phone: 385 (0)1 425 809; Fax: 385 (0)1 434 467; Fax: 385 (0)1 425 497; E-mail: obelic@olimp.irb.hr; E-mail: horvatin@olimp.irb.hr; E-mail: krajcar@olimp.irb.hr

Summary: Measurements of the specific activity of cosmogenic radionuclides (tritium, H-3 and radiocarbon, C-14) and radionuclides of uranium series were enabled in the last thirty years by the development of the measuring techniques. By C-14 dating method the ages of numerous archaeological, palaeontological and geological samples were determined. Hydrological characteristics (the mean residence time, recent infiltration, recharge area) of water-bearing layers of geothermal waters in NW Croatia and groundwaters in E Croatia were determined by isotopic methods (H-2, H-3, C-13, C-14, O-18). Geochronology of quaternary deposits, especially in karst regions in numerous speleological and travertine findings was determined. Cave formation and travertine deposits were dated by C-14 method up to 40000 years and by isotopes from uranium series (U-234/U-238, Th-230/U-234) up to 400000 years. The process of carbonate precipitation in freshwater has been studied by physico-chemical, isotopic and biological measurements. Measurements of C-14 and H-3 in the atmosphere, biosphere and hydrosphere have been applied in ecological studies. These characteristic applications of measurement of low specific activity were enabled by fundamental researches in the field of detection of ionizing radiation. The most important quantities studied in this project are the mean energy required to form an ion pair (W) in pure gases and gas mixtures, statistical fluctuations of the number of formed ion pairs (the Fano factor F) and charge multiplication in detectors. Theoretical study of interaction of electrons with atomic and molecular gases has been extended to subexcitation and thermal electrons.

Keywords: radioactive isotopes, H-3 (tritium), C-14 (radiocarbon), radiocarbon dating, stable isotopes, H-2, C-13, O-18, Th-230/U-234 dating, archaeology, hydrogeology, geochronology, aquatic chemistry, ionizing radiation, mean energy to form an ion pair (W), gas mixtures, electron degradation, electron thermalization

Research goals: The activity in the Laboratory was directed into two scientific fields: ISOTOPIC INVESTIGATIONS: Isotopic composition of surface and groundwater compared with the isotopic composition of precipitation gives important information about water movement: mean residence time of water in aquifers, the catchment area and the mixing ratio of groundwaters with surface waters. The data obtained have a significant application in hydrological investigations, contamination of surface and groundwaters and in investigation of precipitation processes of carbonates in karst waters. Measurement of the C-14 activity in various geological samples (carbonate sediments as speleothems, tufa and lake deposits) give important information about the age of geological formations in Holocene. Measurements of the concentration of isotopes C-14 and Th-230/U-234, as well as O-18, in carbonate sediments give a significant contribution to the study of palaeoclimatic conditions of the formation of quaternary depostis. Dating of archaeological samples of organic origin (bones, wood, charcoal, linen) is one of basic applications of radiocarbon method. The C-14 activity in the atmosphere and biosphere is systematically measured in order to determine environmental contamination. IONIZATION PROCESSES IN GASES: Exact knowledge of W values, the mean energy required to form an ion pair, is important in various applications of ionizing radiation, as well as in theoretical investigations. One of the goals of this project is to assess critically the existing W and F values for various ionizing particles in a variety of gases with an emphasis on gas mixtures. The aim of the experimental investigation of ionization in gases is to determine dependence of W and F values on the mixture parameters and the conditions in the proportional counter, as well as to define the experimental conditions that result in the best energy resolution. The goal of theoretical studies of electron degradation process in various energy regions is to define some fundamental principles underlying the degradation process in various gases and gas mixtures. These principles can be useful for application in plasma physics and radiation detection development.

COOPERATION - PROJECTS

Name of project: CI1/900589 Application of Analytical Methods in Archaeology
Name of institution: Commission of the European Communities, DG XII G3, SDME R2/144
City: 1049 - Bruxelles, Belgija
Name of project: JF-802/NSF Total Ionization Yield, the Fano Factors and Stochastic Distribution of Ions in Gases of Radiological Interest
Name of institution: National Science Foundation (US-Yugoslav Joint Board for Scientific Research)
City: DC - Washington, SAD
Name of project: JF-800/NSF Study of Origin and Diagenesis of Travertine Deposits
Name of institution: National Science Foundation (US-Yugoslav Joint Board for Scientific Research)
City: DC - Washington, SAD
Name of project: JF-839/NSF The Role of Biota in the Precipitation of Calcium Carbonate in Freshwater
Name of institution: National Science Foundation (US-Yugoslav Joint Board for Scientific Research)
City: DC - Washington, SAD
Name of project: 5293/RB Total Ionization Yield for Low Energy Photons and Electrons Absorbed in Polyatomic Gases and Tissue-equivalent Gas Mixtures
Name of institution: International Atomic Energy Agency
City: 1400 - Beč, Austrija

COOPERATION - INSTITUTIONS

Name of institution: Centro ricerca applicata e documentazione
Type of institution: Institution whose primary activities ar
Type of cooperation: Systematic exchange of information
City: 33100 - Udine, Italija
Name of institution: Inštitut Jožef Stefan
Type of institution: State institute
Type of cooperation: Systematic exchange of information
City: 61000 - Ljubljana, Slovenija
Name of institution: Filozofski fakultet Sveučilišta u Zagrebu
Type of institution: University/Faculty
Type of cooperation: Systematic exchange of information
City: 10000 - Zagreb, Croatia
Name of institution: Znanstvenoistraživački centar Hrvatske akademije znanosti i umjetnosti
Type of institution: Other
Type of cooperation: Systematic exchange of information
City: 10000 - Zagreb, Croatia
Name of institution: Institute of Isotopes of the Hungarian Academy of Sciences
Type of institution: Other
Type of cooperation: Systematic exchange of experts
City: 1525 - Budapest, Mađarska
Name of institution: International Atomic Energy Agency
Type of institution: International organization
Type of cooperation: Systematic exchange of information
City: 1400 - Beč, Austrija
Name of institution: Argonne National Laboratory
Type of institution: State institute
Type of cooperation: Joint publishing of scientific papers
City: 60439 - Argonne, Illinois, SAD
Name of institution: Physikalisch-Technische Bundesanstalt
Type of institution: State institute
Type of cooperation: Systematic exchange of experts
City: 38116 - Braunschweig, Njemačka
Name of institution: University of Glasgow
Type of institution: University/Faculty
Type of cooperation: Systematic exchange of information
City: Glasgow, Scotland, Velika Britanija
Name of institution: Universitat Autonoma de Barcelona - Department de Geologia, Unitat de cristal.lografia
Type of institution: University/Faculty
Type of cooperation: Systematic exchange of experts
City: 08193 - Bellaterra/Barcelona, Spanjolska
Name of institution: University of Texas
Type of institution: University/Faculty
Type of cooperation: Joint project
City: Houston, Texas, SAD
Name of institution: Geološki institut Zagreb
Type of institution: State institute
Type of cooperation: Systematic exchange of information
City: 10000 - Zagreb, Croatia
Name of institution: INA - Geološki konzalting
Type of institution: Economical/Production
Type of cooperation: Occasional exchange of information
City: 10000 - Zagreb, Croatia
Name of institution: Geološki fakultet, Zagreb
Type of institution: University/Faculty
Type of cooperation: Systematic exchange of information
City: 10000 - Zagreb, Croatia
Name of institution: Geološki zavod Ljubljana
Type of institution: State institute
Type of cooperation: Systematic exchange of information
City: 61000 - Ljubljana, Slovenija
Name of institution: University of Bern - Institute of Physics
Type of institution: University/Faculty
Type of cooperation: Systematic exchange of experts
City: Bern, Švicarska
Name of institution: University of Bern - Geological Institute
Type of institution: University/Faculty
Type of cooperation: Systematic exchange of information
City: Bern, Švicarska
Name of institution: Brookhaven National Laboratory
Type of institution: State institute
Type of cooperation: Joint publishing of scientific papers
City: Upton, Long Island, New York, USA

Other information about the project.


Ministry of Science and Technology	Croatian language	Svibor homepage	Alphabetic list	Sorted on project code	Sorted on institutions	Search	Help

Last update: 09/25/95
Information: svibor@znanost.hr