The Microirradiation, Neutron Metrology and Dosimetry Laboratory (LMDN) is located in south-east of France, at Cadarache.
The activities of LMDN mainly concern metrology and spectroscopy of neutron radiation fields, through the following missions:
- Conduct studies and research on techniques for characterization of mixed radiation fields (n, gamma) energy distributions of neutron fluence. In particular, implement experimental means and associated simulation means involved in the field of neutron spectrometry;
- Develop and operate facilities providing neutron reference radiation and associated instruments for neutrons metrology. These facilities are in place for internal needs of the IRSN in its dosimetry studies. They are also available to any user outside, including for calibrations needs, as part of BNM/COFRAC. The LMDN is a laboratory associated with the French National Bureau of Metrology (BNM);
- Carry out studies and metrological expertises aimed at characterizing the radiation field at work stations, especially in mixed field (n, gamma), in the areas of civil and military nuclear activities;
- Realize provisions of benchmarking services, studies and expertises for the qualification and good use of radioprotection instruments.
Vincent Gressier, head of laboratory
Bruno Asselineau, engineer
Richard Babut, researcher
Véronique Lacoste, researcher
Nelson Magalotti, engineer
Alain Martin, analysis technician
Jérôme Médard, engineer (CNRS/LPSC)
Michel Pepino, technician
Michael Petit, engineer
François Vianna, research engineer
Thibaut Vinchon, researcher
Jean-Christophe Vola, technician
Facilities and techniques
LMDN facilities at Cadarache help to develop and evaluate the performances of various detectors used in neutron measurement. These performances can be studied in a wide energy range (10 decades) to cover up situations that can be encountered on the various workplaces. For this purpose, several approaches are used by the LMDN:
The study and calibration of dosimeters with the Van Gogh irradiator of the CEZANE facility, consisting of three sources of reference (americium-beryllium and californium alone and californium moderated by deuterium) emitting neutrons in a range of intermediate and high energy (fast neutron) defined and constant, in accordance with ISO standards. Through these sources, the IRSN is associated laboratory at the National Metrology Office (BNM) and is accredited by COFRAC for calibration of detectors and dosimeters (Accreditation n° 2-55 available on www.cofrac.fr
). This irradiator allows to study and to calibrate measuring instruments with respect to fixed references, that do not often match with situations of exposure observed at the workplace.
The study and testing of dosemeters on neutron energy distributions corresponding to the conditions actually observed at the workplace. These studies are carried out in CEZANE facility with two electrostatic accelerator producing neutrons of fixed energy (by approximately 3 and 14.5 MeV) coupled to a moderator device named CANEL. These facilities can experimentally produce a neutron beam with a "realistic" energy distribution, very close to the observed conditions at the workplace. They also allow to assess the performance of detectors and dosimeters under conditions similar to their actual use.
The study of the response of measuring instruments according to the energy of neutrons. To evaluate the behavior of radioprotection instruments with regards to the radiation energy, they should be placed in a neutron field of well-defined and well known energy (monoenergetic neutrons), and to vary the energy with perfect control. In 2000, the IRSN decided to establish a facility, called AMANDE, to produce mono energy neutrons of metrological quality. This facility is operational since 2006.
The laboratory is involved in:
The characteristics of radiation fields in nuclear (research, industry, medical) and military environments
The control of performance and knowledge of the behavior of neutron measuring devices in different nuclear environments,
The control of analysis tools (codes of deconvolution, data processing, determination of uncertainties, etc.).
The study and "realistic" reproduction in the laboratory of neutron radiation fields, representative of those encountered in a nuclear environment, in order to study the response in equivalent dose and the calibration factor that best suits the actual situation of exposure of radiation devices.
The laboratory has the means of calculation (such as Monte-Carlo codes of transport) to model as well its reference facilities, the environments for which it realises expertises and for the characterization of different neutron measuring instruments that it uses or characterize for their approval.
The laboratory also participates in national and international working groups for standards in the field of neutron metrology (ISO, ICRU, ICRP, etc.).