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ePaper created 2013-08-02, 08:40:53 | version 1.25.20
2|2013 Research in Jülich 19 involves a neutron beam that briefly acti- vates the atomic nuclei in the material to be analysed. The activated nuclei react promptly – within a maximum of a tril- lionth of a second – by emitting gamma radiation characteristic of each element. The result is a spectrum of signals, the position and amplitude of which provide information on the type and quantity of the elements contained in a drum. In the subsequent period, Mauerhofer and his then PhD student John Kettler, who now works at the Institute of Nuclear Fuel Cycle at RWTH Aachen Uni- versity, set up a test facility, initially for 100-litre drums, and later, with PhD stu- dent Andreas Havenith, for 200-litre drums. This facility included a commer- cial neutron source. The rod-shaped de- vice irradiates the specimen with neu- trons, electrically neutral building blocks of atomic nuclei that do not occur natu- rally in isolation. Further components of the facility include a graphite chamber that decelerates the neutrons and re- flects them, and a detector that mea- sures the prompt gamma radiation of the specimen. PATENT PENDING The team headed by Mauerhofer invest- ed the most time and energy in the de- velopment of software that delivers nu- merical values for the composition of elements from the gamma spectrum obtained. A patent application has been filed for the new analysis technique. The scientists named the entire method MEDINA, which is short for ‘Multi- Element Detection based on Instrumen- tal Neutron Activation’. Mauerhofer is familiar with the reser- vations that crop up when people hear about the planned use of MEDINA for the analysis of electronic waste. “Yes, radiation protection measures are nec- essary,” he confirms. But, he continues, similar measures are also necessary in doctors’ surgeries and medical laborato- ries when taking X-rays or handling radioactive substances. “In addition, the radioactivity of the investigated materi- als no longer exceeds the natural radio- activity of a potato, for example, only half an hour after the measurement,” says Mauerhofer. He is convinced that MEDINA is much more efficient than conventional analysis techniques: “The latter require a lot of staff and time, not to mention the chemicals and energy that are needed for wet-chemical sample prepa- ration.” Above all, however, MEDINA does away with the need for the com- plex sampling process involved in tech- niques currently used. MEDINA would allow waste to be screened automati- cally on a conveyor belt for valuable ma- terials, so to speak. However, for this scenario to become reality, the scien- tists are reliant on support from indus- try. They have to adapt MEDINA to suit the needs of the recycling sector in terms of detection limits and reliability of analyses. Technology transfer expert Mahr is optimistic: “The interest is there, and we’re already in concrete ne- gotiations with one company on joint further development.” :: Dr. Frank Frick RESEARCH AT THE CENTRE | Innovations having to open them,” says Dr. Eric Mauerhofer from IEK. According to cur- rent planning, these drums will be taken to Schacht Konrad near the town of Salzgitter for final disposal from 2019. They contain radioactive elements as well as toxic agents, including lead, cad- mium, and mercury. The regulatory au- thorities have set limits for their final disposal that must be met – this is the reason for the search for a safe and in- expensive method of analysing the con- tents of these drums. Mauerhofer was convinced that a measuring technique he was familiar with could do the trick: prompt gamma neutron activation analysis. This method Dr. Andrea Mahr has sounded out the market for the new technology. Dr. Eric Mauerhofer has developed the MEDINA measuring technique and is now planning to fit it up for efficiently analys- ing electronic waste. 300g gold 100g palladium