09.03.2007
PARTNER SEARCH FOR FP7 PROJECT ENV.2007.1.2.1.1.
Contact person
dr Nataša Todorović
e-mail: zikic@im.ns.ac.yu
The Nuclear Physics Laboratory, member of Department of Physics, Faculty of Sciences,
University of Novi Sad Serbia, have a long-term experience of indoor radon
measurements. The Laboratory is the national focal point for European radon mapping by
the European Commission Joint Research Centre (http://radonmapping.jrc.it).
The list of present equipment for radon measurements is given below:
1. Alpha-ray spectrometer dedicated to the measurement of low levels of radon, and
other alpha-ray emitting isotopes, in different gaseous and liquid media. Canisters
with charcoal for passive adsorption of radon from the air, the gamma-ray
spectroscopy of which, providing proper calibration, yields the concentration of
radon in the air.
2. Two hyper pure HPGe germanium spectrometers of nominal efficiencies of 36%
shielded by 12 cm thick lead shield with the Canberra four input Multiport data
acquisition system.
3. The big low-background iron chamber of a useful volume of 1 m3, with 25 cm thick
walls, made out of pre-WWII iron (free of 60Co). The chamber accommodates
another HPGe detector actively shielded with a large (9”x9”) NaI(Tl) annulus
acting also as a Compton suppressor.
4. Shallow underground laboratory. It is situated at the depth equivalent to 30 meters of
water, what reduces the cosmic-ray muon flux 4.5 times as compared to the flux at
the surface. It has an active area of about 60m2 and is completely lined with
aluminum foil 1 mm thick, which is hermetically sealed against the penetration of
radon from the surrounding soil and concrete used for construction. The laboratory
is continuously ventilated with fresh air which is filtered through the battery of
coarse and fine charcoal active filters in such a way that an overpressure of some 2
mbar is maintained over the atmospheric pressure. This is aimed at keeping the
radon from eventually leaking into the laboratory. The levels of radon lower than 10
Bq/m3 are routinely achieved. The pressure-buffer corridor with double air-tight
doors keeps the laboratory space radio pure.
Sampling strategy:
Indoor radon activity concentration in air has been measured at the whole area of the
province Vojvodina. Special attention has been paid to rural regions of 45 municipalities
and type of dwellings, characteristic for Vojvodina region. The main aim of the present
study was to exploit the critical group for radon exposure. Thus the mean values obtained
for the whole region should be most probably considered as upper limits at the evaluation
of the radon doses.
The Southern area of the country is geologically very different from the Danube Basin
and probably will be faced with the quite different radon build-up problems.
Measurement technique
Detector type
Track-etch
detectors
(CR-39)
Measurements time
(days)
90
Season
Winter
Measurement
location
Living room
Measurement time (units in days)
Detector type
Mean Std. Dev. Min. Max.
Track-etch detectors
90
NA
NA
NA
Statistics of the measurements
3
Measurements statistics (units in Bq/m )
Measurements Mean Geo. Mean Std. Dev. Min. Max.
968
144
104.6
120
2
893
Estimated mean annual radon levels in dwellings of the Province of
Vojvodina
3
Mean
% of dwellings above 200 Bq/m and % of dwellings above
3
(Bq/m )
144
below 400 Bq/m
18
3
3
400 Bq/m
4
Maps:
Indoor radon activity concentration in air has been measured at the whole area of the
province Vojvodina (on 1000 locations) by plastic track detectors CR-39. On the base of
the obtained results, the average indoor activity concentrations of 222Rn for individual
municipalities and for the whole province of Vojvodina were estimated. In Vojvodina
the average indoor radon activity concentration yields 144 Bq/m3 .
Distribution of indoor radon activity concentrations measured by CR-39 during the
period December 2002 – March 2003
Radon
map of Vojvodina. Numbers given along the names of municipalities indicate
geometric mean radon concentration in Bqm-3.
The method of the adsorption on activated charcoal canister was applied in some
measurements of radon activity concentrations. The canister gamma activity (the activity
of 214Bi and 214Pb radon daughters) was measured by means of high resolution
germanium and NaI(Tl) scintillation spectrometers. The efficiency of the detectors was
determined using the EPA 226Ra Reference source. The canisters were exposed for two
days. The typical time between the end of the exposion and the beginning of the
measurement was about two hours. Gamma spectrometric measurements were performed
with high resolution HPGe gamma spectrometer with nominal efficiency 22%, was
placed in another schielding chamber with iron walls 25 cm thick. In order to achieve
5% statistical accuracy at 100 Bq/m3 the time of measurement was usually 1 hour. In our
measuring chamber the radon levels are very low (less than 5Bq/m3) so radon
fluctuations could not affect the results of most measurements.
On Fig. results of measurements of indoor radon concentrations in Novi Sad flats by
charcoal cannisters are presented. The results of the statistical analysis of about 180
measurements are listed in Table.
Frequency distribution of radon activity concentrations in Novi Sad flats during period
1992-2003
Maximum (Amax), minimum (Amin) and average indoor radon activity concentration Aav
A in Novi Sad flats
radionuclide
222
Rn
Amax
[Bq/m3]
391
Amin
[Bq/m3]
2
Aav
[Bq/m3]
50
A
[Bq/m3]
69
The mean value of indoor radon activity concentration obtained by charcoal canisters
is (50 ± 69) Bq/m3. Only 5 % of the results exceed the 200 Bq/m3 value accepted as an
intervention level in Serbia. The highest results are obtained for flats on ground level.
The owners of this flats and houses were advised how to solve the radon build-up
problem. The lognormal distribution obtained proves the random nature of the radon
build-up in the flats investigated.
The results are above the expectations for the low-land districts and show that
dominant sampling in new city flats can seriously underestimate the radon buildup
problem.
Selected References:
 S. Forkapić, I. Bikit, J. Slivka, Lj. Čonkic, M. Vesković, N. Todorović, E. Varga,
D. Mrđa and E. Hulber (2006) INDOOR RADON IN RURAL DWELLINGS OF
THESOUTH-PANNONIAN REGION, Radiation Protection Dosimetry (2006), 1 of
6 doi:10.1093/rpd/ncl156

Curcic, S., I. Bikit, Lj. Conkic, M. Veskovic, J. Slivka, E. Varga, N. Todorovic, D.
th
Mrdja (2004). The first radon map of Vojvodina. In: Proceedings of the 11
International Congress of the International Radiation Protection Association, 23-28
May 2004, Madrid, Spain (paper 6a11 published on CD).
• Curcic S.M., I. Bikit, J. Slivka, M.J. Veskovic, Lj. U. Conkic, E. Varga (2003).
Radioecological problems in home building in the city of Novi Sad. In: Proceedings
th
of the 6 International Symposium &Exhibition on Environmental Contamination in
Central and Eastern Europe and the Commonwealth of Independent States, 1-4
September 2003, Prague, Czech Republic (Book of Abstracts p.138, published on
CD).
• Curcic, S., I. Bikit, J. Slivka, Lj. Conkic, M. Veskovic, E. Varga, N. Zikic-Todorovic, D.
Mrdja (2003). The first radon map of Vojvodina. In: Proceedings of the XXII
Symposium of Yugoslav Radiation Protection Association, Petrovac, Serbia and
Montenegro, pp. 195-198.
Biography of the key personnel and the staff
Key personnel:
Dr. Istvan Bikit is a Professor of nuclear physics at the Faculty of Sciences in Novi Sad.
He obtained his PhD form the University of Novi Sad in 1976. His international
experiences includes visiting positions at Sussex University (Brighton, UK), ICTP
(Trieste, Italy), Laue-Langevin Institute (Grenoble, France), NIST (Geithersburg, US),
and Institute of Surface Chemistry and Isotopes (Budapest, Hungary). He has led national
and international projects in fundamental and applied nuclear physics research in
continuity from 1981 onwards, including the bilateral project with US “Improvements on
the determination of low-levels of gamma radioactivity” (JF-847 NIST, 1988-90). He
was the Dean of the Faculty of Sciences and is the Director of the Department of Physics,
University of Novi Sad. His research fields of interest are: nuclear structure, low
background gamma spectroscopy, physics of rare nuclear events and radioecology.
Dr. Miroslav Veskovic is Professor of nuclear, particle and medical physics at the
Faculty of Sciences in Novi Sad. He received his PhD degree at the University of Novi
Sad in 1989. He was a research fellow at the Sussex University in 1986-87, Oak Ridge
National Laboratory in 1989, CERN in 1991-92, and a visiting professor at Oxford
University for two years, from 1994 to 1996. Within the Faculty of Sciences in Novi Sad
he has served as the Head of the Nuclear Physics Group (1996-2000) and the Head of the
Department of Physics (2000-2002). He served as the vice-Rector of the University of
Novi Sad in charge of research and development, and currently serves as the Dean of the
Faculty of Sciences. His research interests are low temperature nuclear orientations,
nuclear structure, nuclear spectroscopy, physics of rare nuclear events, low background
gamma spectroscopy, environmental protection, radioecology, and medical physics.
Dr. Ivan Aničin is a Professor of nuclear physics at the Faculty of Physics of the
University of Belgrade. His PHD degree he obtained in 1973, from the University of
Belgrade. His scientific interests are concentrated mainly in the field of different
branches of nuclear spectroscopy, pure and applied. In particular, he specialized in
angular correlations of nuclear radiations, and later on in low-background studies of rare
nuclear and particle processes. He also participates in the CMS collaboration at CERN,
Geneva. He has spent two years in England, France and Germany, collaborating with
different researchers in the field of nuclear physics.
Dr. Jaroslav Slivka is a Professor of nuclear physics at the Faculty of Sciences in Novi
Sad. He obtained his PhD form at the University of Novi Sad in 1986. He was a research
fellow at the Institute of Physics in Zurich University in 1982-1984 working in the field
of Moessbauer spectroscopy. His recent research interests are nuclear structure, physics
of rare nuclear events, low background gamma spectroscopy and radioecology.
Dr. Miodrag Krmar is a Professor of nuclear physics at the Faculty of Sciences in Novi
Sad. He obtained his PhD form at the University of Novi Sad in 1996. As a research
fellow he joint two times the JINR Dubna (Moscow) working on nuclear structure
problems by means of nuclear orientation techniques. His research interests are nuclear
structure, physics of rare nuclear events, low background gamma spectroscopy,
radioecology and medicine physics. He is a member of American Society of Physicist in
Medicine.
Dr Nataša Todorović
Dr Tijana Prodanović
Mr Dušan Mrđa
Mr Sofija Forkapić