Preparation of carbon samples for 14C dating by the AMS technique - AMS 14C
The Radiocarbon Laboratory of the Rudjer Bošković Institute (RBI) in Zagreb has long experience in 14C dating. Since 1969 we have used the gas proportional counter technique with sample conversion to methane, and since 2002 the liquid scintillation counting technique with either benzene synthesis or direct absorption of CO2 obtained from the sample. These techniques require 2-5 g of carbon. In order to expand our activities to very small samples of the size of mg, we developed preparation of carbon (graphite) from small samples for 14 C dating and to measure the prepared graphite targets in one of the AMS (Accelerator Mass Spectroscopy) facilities in Europe, namely SUERC (Scottish Universities Environmental Research Centre, University of Glasgow, UK). To achieve this, we trained our staff in the SUERC AMS laboratory, for a short-term temporary job position for software specialist who would upgrade our preparation and measurement systems. We hosted an expert in AMS dating (from SUERC) who transferred his knowledge and experience, and performed intercomparison studies of samples prepared in our Laboratory and in the SUERC. We asked also for some small pieces of equipment, spare parts, standard samples of known 14C activity and chemicals, with the aim of reinforcing research potential of the Laboratory. The proposal was structured into 6 work packages. The expected results are a fully operational graphite preparation line in the RBI Laboratory; establishment of co-operation with the UGLA-SUERC Laboratory for measurements of the graphite targets using their accelerator; training and career development of researchers in Croatia; improved competitiveness of the RBI Laboratory for future international projects; better opportunities for integration into the European Research Area (ERA), and creation of improved market opportunities for the research centre in WBC. Scottish Universities Environmental Research Centre (SUERC) of the University of Glasgow (UGLA) was the subcontractor on the Project with the major task of measurement of graphite samples prepared at the RBI and participation in the interlaboratory intercomparison. Also, the specialized trainings were realized at SUERC and their experts visited the RBI laboratory. A good co-operation has been established between RBI and SUERC, the experience of the SUERC staff gained in the development of their line, as well as in the day-to-day preparation and measurement routine, helped us in faster implementation of a new system and it is foreseen to continue this co-operation also in future.
Presentation of research results obtained by the existing methods at scientific symposia:
B.Obelić, I.Krajcar Bronić, J.Barešić, A.Sironić, B.Breznik: 14C in biological samples from the vicinity of NPP Krško. IRPA Regional Congress: Regional and Global Aspects of Radiation Protection, Brasov, Romania, 24.9.-28.9.2007. Final Programme and Abstracts. Bucurest, Romania: IRPA, 163-164 T9-P14. Abstract only in Book of abstracts and on web page http://www.irpa2007romania.com/ALL/T9.pdf. Full paper T9-P14 on CD ROM.
I.Krajcar Bronić, K.Minichreiter: New 14C dates of the oldest Early Neolithic settlements in Croatia. Radiocarbon and Archaeology 5th International Symposium, 26-28 March 2008, Zurich, Switzerland, poster presented and abstract published in Proceedings, p.79http://www.c14archaeology.ethz.ch/ProgramAbstracts.pdf .
I.Krajcar Bronić, B. Obelić, A. Sironić, J. Barešić, B. Breznik: 14C in biological samples and in the atmosphere around Nuclear Power Plant Krško (NEK) in Slovenia. IRPA-12 (12th International Congress of the International Radiation Protection Association), Buenos Aires, Argentina, 19-24 Oct.2008. Poster presented, abstract published in Proceedings, p.180.
B.Obelić, I. Krajcar Bronić, J.Barešić, A.Sironić, B.Breznik: 14C activity in close vicinity of NEK. 7th Symposium of Croatian Radiation Protection Association, Opatija, Croatia, 28-31.5.2008., in Proceedings of the 7th CRPA Symposium, Editors: D.Barišić, Ž.Grahek, I.Krajcar Bronić, S.Miljanić. CRPA, Zagreb, Croatia, 2008. 222-229.
I.Krajcar Bronić, N.Horvatinčić, J.Barešić, B.Obelić: Measurement of 14C activity by liquid scintillation counting. 5th International Conference on Radionuclide Metrology - Low-level Radioactivity Measurement Techniques. Braunschweig, Germany, 22 – 26 Sept 2008, PTB, 2008. p.047 (oral presentation).
Presentation of database and research results obtained by the AMS method at scientific symposia:
A.Portner, I.Krajcar Bronić, B.Obelić: ZAGRADA – new radiocarbon database. 7th Symposium of Croatian Radiation Protection Association, Opatija, Croatia, 28-31.5.2008, in Proceedings of the 7th CRPA Symposium, Editors: D.Barišić, Ž.Grahek, I.Krajcar Bronić, S.Miljanić. CRPA, Zagreb, Croatia, 2008, 52-58.
A.Sironić, N.Horvatinčić, I.Krajcar Bronić, B.Obelić, J.Barešić: Measurement of 14C activity by the AMS technique. 7th Symposium of Croatian Radiation Protection Association, Opatija, Croatia, 28-31.5.2008, in Proceedings of the 7th CRPA Symposium, Editors: D.Barišić, Ž.Grahek, I.Krajcar Bronić, S.Miljanić. CRPA, Zagreb, Croatia, 2008, 89-95.
I.Krajcar Bronić, N.Horvatinčić, A.Sironić, B.Obelić, J.Barešić, A.Portner: A new graphite preparation line for AMS 14C dating in the Zagreb Radiocarbon Laboratory . Eleventh International Conference on Accelerator Mass Spectrometry AMS-11, Rome, Italy, 14-19 September, 2008, Book of abstracts printed and available at http://www.ams11.org/public/Bookofabstract_AMS11.pdf (poster presentation).
Popular presentations and public lectures
I.Krajcar Bronić: Kruženje ugljika i vode u prirodi praćeno izotopima / Isotopes in studies of natural carbon and water cycles. In Croatian. Talk and publication in: Fizika u ekologiji - 23. ljetna škola mladih fizičara, (Physics in ecology, 23rd Summer school of young physicists). Eds. T.Ban, Z.Vučić, Labin, 2007. HFD (Croatian Physical Society), Zagreb. 50-59. ISBN 978-953-7178-08-6. http://www.hfd.hr/ljskola/arhiva/2007/zbornik.html .
I. Krajcar Bronić: 14C dating of archaeological artefacts . Lecture,12 Feb.2008 in Sisak, Croatia. In Croatian, to public.
I.Krajcar-Bronić: Implementation of AMS 14C dating at RBI through participation in IAEA and EU FP6 projects , invited talk, IAEA Regional Training Course on How to Write Competitive Research Proposals for Various Funding Programmes, RER/0/023, Zagreb, 18– 20 March 2008.
B. Obelić: Datiranje metodom 14C – nove tehnike na Institutu Ruđer Bošković" / 14C dating – new techniques at the RB Institute , the seminar of the Department of Experimental Physics, Zagreb, 23 Oct 2008.
V.Kotarski: Activities of the Ruđer Bošković Institute in Framework programs. presentation (in Croatian) by RBI – Office for International Projects, Seminar on 7. Framework Program for research and technological development (FP7) – opportunities of cooperation for SME, Zagreb, 6 Nov 2008.
I. Krajcar Bronić: Priprema uzoraka za 14C datiranje AMS tehnikom – o 14C Laboratoriju i projektu AMS-14C / Preparation of carbon samples for 14C dating by the AMS technique – the Radiocarbon Laboratory and the AMS-14C project. Talk at the Workshop on AMS-14C, Zagreb, 29 Nov 2008.
B. Obelić: Određivanje starosti metodom 14C / Radiocarbon dating. Talk at the Workshop on AMS-14C, Zagreb, 29 Nov 2008.
J.Barešić: Priprema uzoraka za datiranje metodom 14C / Sample preparation for 14C dating. Talk at the Workshop on AMS-14C, Zagreb, 29 Nov 2008
I. Krajcar Bronić: Tehnike mjerenja 14C / 14C measurement techniques. Talk at the Workshop on AMS-14C, Zagreb, 29 Nov 2008.
B.Obelić: Primjeri datiranja u arheologiji / Examples of dating in archaeology at the Ruđer Bošković Institute Radiocarbon Laboratory. Talk at the Workshop on AMS-14C, Zagreb, 29 Nov 2008.
N.Horvatinčić: 14C u okolišu: geokronologija, paleoklimatologija i ekologija / 14C in environment: geochronology, paleoclimatology and ecology. Talk at the Workshop on AMS-14C, Zagreb, 29 Nov 2008.
A. Portner: ZAGRADA – nova baza podataka / ZAGRADA – a new radiocarbon database . Talk at the Workshop on AMS-14C, Zagreb, 29 Nov 2008.
B. Obelić: Overview of dating results at the RBI Radiocarbon Laboratory. Lecture at Regional Training Course on Dating Techniques in Archaeometry, Zagreb, Croatia, 5-9 May 2008.
I.Krajcar Bronić: The earliest Neolithic settlements in Croatia. Lecture at Regional Training Course on Dating Techniques in Archaeometry, Zagreb, Croatia, 5-9 May 2008.
N. Horvatinčić: AMS and Radiometric Dating of an Etruscan Book and Associated Mummy from the Archaeological Museum in Zagreb , Lecture at Regional Training Course on Dating Techniques in Archaeometry, Zagreb, Croatia, 5-9 May 2008.