Intercomparison of radiation protection devices in a high-energy stray neutron
ﬁeld, Part I: Monte Carlo simulations
, S. Agosteo
, G. Fehrenbacher
, C. Hranitzky
, T. Radon
, M. Wind
Austrian Research Centers GmbH – ARC, 2444 Seibersdorf, Austria
Politecnico di Milano, Dipartimento di Energia, piazza Leonardo da Vinci 32, 20133 Milano, Italy
r Schwerionenforschung – GSI, Planckstrasse 1, 64291 Darmstadt, Germany
Received 27 June 2008
Received in revised form
12 November 2008
Accepted 15 March 2009
An intercomparison of radiation protection devices in a high-energy stray neutron ﬁeld was held in the
framework of the COordinated Network for Radiation Dosimetry [CONRAD, http://www.eurados.org/
conrad/conrad_overview.htm], ﬁnanced by the European Commission. An irradiation hall of the GSI
r Schwerionenforschung, Darmstadt, Germany) was the facility selected for this bench-
mark experiment. The measurements were carried out outside the shielding barriers of this facility,
while bombarding a thick carbon target with a beam of 400 MeV/u carbon ions. This paper describes the
Monte Carlo simulations which were performed in order to characterize the radiation ﬁeld at the
measurement positions. Two codes were used for this purpose, namely FLUKA and MCNPX. Different
approaches were adopted for the simulations and the results are compared and discussed. The results of
the different simulations were in a satisfactory agreement. The comparisons with the measurements are
discussed in Wiegel et al. [Intercomparison of radiation protection devices in a high-energy stray neutron
ﬁeld. Part II: Bonner sphere spectrometry. Radiat. Meas., 2008] and Silari et al. [Intercomparison of
radiation protection devices in a high-energy stray neutron ﬁeld. Part III: instrument response. Radiat.
Ó 2009 Elsevier Ltd. All rights reserved.
In the framework of the Coordinated Network for Radiation
Dosimetry (CONRAD), two working groups, WP4 ‘‘Computational
Dosimetry’’ and WP6 ‘‘Complex Radiation Fields at Workplaces’’,
collaborated on a dosimetry intercomparison held at an irradiation
facility delivering carbon ion beams. The organizational framework
for this project was provided by the European Radiation Dosimetry
Group EURADOS. The two groups focussed their common tasks on
the dosimetry of the radiation ﬁelds outside the shields of an
experimental hall at GSI (Gesellschaft fu
Darmstadt, Germany). The intercomparison was set up by using
a beam of 400 MeV/u carbon ions impinging on a thick carbon
target. Since the maximum energy of the carbon ion beams
employed for radiation therapy of deep-seated tumours is
400 MeV/u, this represents a typical situation encountered at
workplaces in hadrontherapy centers. A thick carbon target was
used since the secondary radiation (mainly neutrons) produced is
representative of that generated during patient’s irradiation (ICRU,
The number of hadrontherapy facilities performing carbon ion
therapy is growing all over the world (see Ref. PTCOG). Together
with GSI (Darmstadt, Germany), HIMAC (Chiba, Japan) and HIBMC
(Hyogo, Japan) are operating, while CNAO (Pavia, Italy), the one in
Heidelberg (Germany), the one at Gunma University (Japan) and
PTC (Marburg, Germany) are under construction. Other facilities
like MED-AUSTRON (Austria) are still at the stage of feasibility study.
The dosimetry of the radiation ﬁelds at these workplaces is there-
fore of primary importance and requires a careful investigation.
Radiation therapy was routinely performed at GSI in Cave M
(Fig.1). Cave A was chosen for the present experiment as a facility for
simulating the radiation ﬁelds at workplaces, in order not to inter-
fere with patients’ irradiation during the measurement campaign.
The task of WP4 was to simulate Cave A and to calculate the dose
and the neutron spectra outside the shielding barriers, while that of
WP6 was to compare various detection systems and techniques for
the dosimetry of these radiation ﬁelds. This work mainly focuses on
the description and the discussion of the Monte Carlo simulations.
The measurements and the comparison of the calculations with the
Corresponding author at: Austrian Research Centers GmbH – ARC, Health
Physics, 2444 Seibersdorf, Austria. Tel.: þ43 50550 2482; fax: þ43 50550 2502.
E-mail address: soﬁa.firstname.lastname@example.org (S. Rollet).
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1350-4487/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved.
Radiation Measurements 44 (2009) 649–659