Neutrons instead of alchemy – tracing elements at the Deutsches Museum

Can gold really be made from lead? Dr Christian Stieghorst posed this ever-present question in his lecture at the Deutsches Museum. The instrument scientist specialising in Prompt Gamma Activation Analysis (PGAA) and Neutron Activation Analysis (NAA) at FRM II in Garching has long been involved in neutron research and, for one evening, offered insights into the diverse world of analytical methods using neutrons.

Elemental analysis with neutrons – a multi-purpose method

Neutrons are particularly well suited to research because they penetrate deep into matter without damaging it, whilst delivering highly precise measurement results. The interaction between neutrons and atomic nuclei releases characteristic gamma radiation – and this radiation can be used to determine exactly which elements are present in a sample and in what quantities. This technique is also used in PGAA and NAA.

Searching for chemical fingerprints

Neutron-based elemental analysis is used in a wide variety of research fields: in environmental research, for example, where lichens are used as ‘biomonitors’. “Lichens just happen to be growing on trees. They take all their nutrients from the air – and pollutants along with them,” explains Christian Stieghorst. These substances can then be analysed in the laboratory to determine their concentration and exact composition.

Following the talk, the audience had a number of questions, which Christian Stieghorst answered. The most important question, however, remained: Can gold really be produced using neutrons from lead? The short answer: Unfortunately not. Christopher Stieghorst explains why exactly in his talk, which is still available to watch on YouTube.