Hannover Messe Moderator for neutron beam sources: Researchers show a cold heart

Editor: Theresa Knell

As a contribution to the European Spallation Neutron Source, Jülich Research Centre has developed a special moderator. These scientists are presenting the project at the fair.

Cold hearts during a test with liquid nitrogen (T = -196 °C).
Cold hearts during a test with liquid nitrogen (T = -196 °C).
(Source: Hannover Messe)

The European Spallation Neutron Source (ESS) is being built in Lund in southern Sweden for 1.85 billion euros. The German share amounts to around 190 mln. euros and is coordinated by the research centre in Jülich.

For this project, the researchers in Jülich have developed, using a high-strength aluminium alloy, a moderator filled with para-hydrogen. This pressure vessel, known as the Cold Part, is operated at -250°C and 10 bar pressure, dissipating at the same time around 4000 W of radiant heat. Its task is to slow down to 0.5 km/s neutrons coming from the target at around 20,000 km/s during experiments. Only at this reduced speed do experiments become possible. This relatively small element also determines the quality of the neutron beam, the Hannover Messe reports. There are always two hearts joined to a cooling structure to form one unit for slowing the neutrons before they enter the beamline and to enable experiments.

Visit Forschungszentrum Jülich at Hannover Messe in Hall 2, Booth B30 (Joint Booth Nordrhein-Westfalen).

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