For the Earth and in Space: New Measuring Device for Monitoring Radiation

A new type of measuring device which can even register several types of radiation simultaneously, comes at the right time here. The physicist Dr. Marlies Luszik-Bhadra from the Physikalisch-Technische Bundesanstalt has, together with a partner from industry, developed a measuring device which can measure neutron- and photon radiation at the same time.

This personal dosimeter is a handy device which has a direct readout and an alarm function. It was possible by means of an invention – the essential principles of which have been patented – to make the dosimeter especially light and compact. For the technology transfer to the Synodys group, Marlies Luszik-Bhadra and her colleagues Wilfried Wendt and Mathias Weierganz receive this year's Technology Transfer Prize of the Industrie- und Handelskammer Braunschweig (Braunschweig Chamber of Commerce and Industry).

Natural neutron radiation surrounds us constantly – caused by the collision of high-energy cosmic particles with the molecules of our Earth's atmosphere. The intensity of this neutron radiation increases thereby with height and is especially relevant for flights, so that the radiation dose of flight personnel is continuously monitored. In contrast to this, humans themselves are responsible for the artifical neutron radiation on the ground. It is found in medical applications such as in tumour therapy, is used in non-destructive material testing, and is always present in nuclear power plants.

In general, however, neutron radiation seldom occurs alone. In most cases it is even the smaller component – above all in comparison to photon radiation (gamma radiation). A measuring device which includes both radiation components simultaneously is thus an ideal tool to monitor radiation-critical environments.

The personal dosimeter developed by Luszik-Bhadra, together with the Synodys group, is able to measure both radiation components in a handy and moreover very light device. It is the currently smallest dosimeter for mixed neutron/photon radiation fields. Compared to conventional laboratory electronics, the construction is smaller by a factor of 1000. The innovative idea thereby is in the interior construction of the detector. Whereas up to now, several semiconductor detectors have always been used for the construction of a neutron dosimeter, the new dosimeter gets by with a single detector surrounded by several thin absorber layers.

Hence the dosimeter is open to diverse fields of application: from medicine to nuclear technology and also to space-related assignments. For the crew of the International Space Station ISS – a place with especially intensive radiation – the measurement of the current radiation exposure is of particular importance. Up to now, passive dosimeters have been used here which can only be evaluated later on the Earth. A test application of the new direct-readout dosimeter is now being discussed with the European Space Agency ESA.