First Neutrons from Next Generation Neutron Source in Jülich
20 December 2022
Accelerator-driven, low-energy compact neutron sources are considered worldwide as the next generation of neutron sources for a wide range of applications. Researchers from JCNS at Forschungszentrum Jülich have now achieved a breakthrough by delivering the first neutrons using a new powerful target/moderator technology developed in Jülich.
More than 16 years after the permanent shutdown of the DIDO research reactor at Forschungszentrum Jülich, a new type of neutron research facility was put into operation on the FZJ site. Currently, the platform houses three beamlines: a detector test stand, a time-of-flight (ToF) diffractometer, and the HERMES neutron reflectometer from the decommissioned Orphée reactor, contributed through a collaboration with LLB (Saclay).
This impressive milestone was achieved on 12 December 2022 as part of the High Brilliance Neutron Source (HBS) project with the first neutrons at the Target Moderator Reflector (TMR) unit of an experimental test station for a High Current Accelerator-driven Neutron Source (HiCANS) in the "Big Karl" area of the Institute of Nuclear Physics (IKP). Protons delivered by IKP's JULIC cyclotron produced these first neutrons at the tantalum target developed for the HBS project at TMR. Both thermal and cold neutrons were measured at all three positions around the TMR facility.
The TMR unit was developed over the past two years and is the result of a collaboration between JCNS and ZEA-1. The 68-ton biological shielding is a unique modular design that can accommodate up to 8 individual experiments. It is connected to the IKP's JULIC proton cyclotron via a dedicated proton transfer beamline. A newly developed high-power tantalum neutron target with an internal microfluidic water-cooling loop was installed to test its performance for the HBS neutron source project. A methane-based cryogenic cold moderator system for cold neutron production was also introduced and tested.
In collaboration with CEA / LLB, the former HERMES time-of-flight reflectometer was transferred from Saclay to Jülich and installed in the Big Karl area. It will be used to demonstrate the performance of a reflectometer at a pulsed neutron source based on an accelerator.
The new neutron source will be used to gain experience in handling targets and moderators and to develop advanced moderators and reflectors for the future HBS as well as instrument concepts. In the process, the neutron flux is not very high due to the low current of the proton beam, so experiments to prove the principle can be performed and developed.
This great achievement required many different types of expertise and was made possible by the excellent collaboration between several institutes and infrastructure units within FZJ - from engineering (ZEA-1) and infrastructure (T) to nuclear physics (IKP), neutron research (JCNS) and external collaborations, in particular with LLB, France.
With the installation of the replica of the HBS TMR unit, Forschungszentrum Jülich has taken an important step towards HiCANS neutron sources that will provide brilliant beams for science and industry at resilient, sustainable, flexible neutron research facilities with moderate operating costs and easy user access.