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NAVIDOS has started its measuring operation on a Lufthansa Airbus A340 since August 15, 2008

29.09.2008

After an extensive testing phase, the dosimetry system NAVIDOS, developed by PTB and Christian Albrechts University in Kiel, was installed by Lufthansa Technik in August 2008 on a Lufthansa Airbus A340-300 and put into operation on August 15, 2008. The aim of the measurements is to investigate the influences which solar activity, for example, or the change of the magnetic field of the Earth have on the area dose rate at flight altitudes. In addition, the measurements serve to ensure the quality of the dose determination for the flying personnel.

With the introduction, in 2001, of the new Radiation Protection Ordinance, the EU Directive 96/29/EURATOM - which had already been valid for some time - was transposed into national law also in Germany. As a result, flying personnel are now regarded as being "occupationally exposed to radiation". In Germany, approx. 30,000 persons fall into this group. The radiation dose is determined in accordance with a recommendation from the Radiation Protection Commission, by means of computational programs which have been tested by the Physikalisch-Technische Bundesanstalt (PTB) and have been approved by the Federal Civil Aviation Authority. For the testing, dose measurement values are used which have been determined at different flight altitudes worldwide.

Due to the size of the flight case and its mass of more than 20 kg, further technical improvements became necessary through which installing the flight case in a passenger aircraft is considerably facilitated. Here, the miniaturization of the measuring instruments represented significant progress. For this purpose, the NAVIDOS (Navigation & Dosimetry) measuring system was developed in a cooperation between PTB and the Institute for Experimental and Applied Physics of the Christian Albrechts University in Kiel (CAU). NAVIDOS is based on the dosimetry telescope ("DOSTEL") developed in 1996 by the CAU and the Deutsches Zentrum für Luft- und Raumfahrt (DLR, German Aerospace Center). This particle telescope - which relies on two Si semiconductor detectors - was conceived for measurements in space. In designing the instrument, the requirements of the American Space Agency NASA with respect to power consumption, insensitivity to vibrations, flashing and electromagnetic radiation were taken into account. During measurements performed on the NASA shuttle flights STS76 (1996), STS81 (January 1997) and STS84 (May 1997) and at the space station MIR (October 1997 to January 1998), DOSTEL furnished proof of its efficiency. Two DOSTEL units were, among other things, used for the Dosimetric Mapping (DOSMAP) experiment (April 2001 to July 2001) at the International Space Station ISS. Currently, an enhanced instrument is carrying out measurements as a radiation monitor on the European Exposure Technology Facility (EuTEF). Also in measurement campaigns for area dose rate measurements in passenger aircrafts, DOSTEL has proved to be a reliable measuring instrument.

Furthermore, NAVIDOS comprises a highly sensitive GPS receiver, a sensor for measuring the ambient air pressure and a miniature data logger which has been developed by PTB and ensures a simultaneous readout of all the measurement data (energy spectrum and counting rates, local data and air pressure) and their storage on an externally accessible SD memory card. Thanks to its compact construction (approx. 17 cm x 17 cm x 12 cm; mass: approx. 4 kg), NAVIDOS is considerably lighter than the flight case. This facilitates individual measuring flights as well as its installation in passenger aircrafts.

After an extensive testing phase, NAVIDOS was installed by Lufthansa Technik in August 2008 on a Lufthansa Airbus A340-300 and put into operation on August 15, 2008. The aim of the measurements is to investigate the influences which solar activity, for example, or the change of the magnetic field of the Earth have on the area dose rate. In addition, the measurements serve to ensure the quality of the dose determination for the flying personnel.

The measurements are performed within the scope of the RAMONA ("Radiation Monitoring Onboard Aircraft") cooperation, for which PTB, the Institute for Experimental and Applied Physics of the Christian Albrechts University Kiel (CAU), the Radiation Biology Department of the Institute for Aerospace Medicine of the German Aerospace Center (DLR), the Institute for Geophysics and Extraterrestrial Physics of the Braunschweig Technical University, Deutsche Lufthansa AG (DLH) and the air transport company LTU have joined together. The development of NAVIDOS was promoted by the Federal Ministry for Transport, Building and Urban Affairs (Research Project L-4/2006-50.0320./2006 "Radiation exposure at flight altitudes").

The NAVIDOS measuring system (left) was installed in a Lufthansa Airbus A340-300 (right).