The BER II neutron source is back in operation and available for experiments following the interruption in availability
The High-Field Magnet (HFM) has attained 26 tesla in an initial test and thereby exceeded expectations. The HFM team is pleased about the well-deserved success.
© HZB/Ingo Kniest
Maintenance work has been successfully concluded – the High-Field Magnet has successfully attained 26 tesla in initial testing. New scientific experiments have become possible.
Berlin, February 2015: following conclusion of more than a of year of repairs and refurbishing, the BER II neutron source will shortly be available to its international user group again. The facility was powered up on Wednesday, February 18 and attained its nominal power level of 9,5 megawatts. Scientists of HZB are meanwhile preparing the measurement equipment so that experimental work can resume following a brief start-up period.
During the service interruption, a weld joint was eliminated that was known to be a potential weak point. This involved a weld joint for a seal located in the area of the separator between the two reactor pool halves. Damage to this weld joint was discovered in 2010 and has been carefully monitored since that time. This did not involve a component critical to safety; nevertheless, it was decided in 2013 to completely remove the weld joint.
At the same time, the new High-Field Magnet went through final assembly and was setup in its final operating position inside in the Neutron Guide Hall. Its 26-tesla magnetic field was first generated in December 2014 and it maintained this value stably over a longer period of time. So it even exceeded its target value of 25 tesla.
Following the maintenance period, an important objective was reached with the successful resumption in BER II operations: participants of the international Neutron School can again be offered actual neutron experiments of the customary high quality. The 12-day advanced course for young scientists will be taking place in Berlin for the 35th time, from February 26th to March 6th.
Developing and successfully setting up the High-Field Magnet, unique for neutron experiments, has only taken 7.5 years. All of the comparable hybrid magnet construction projects worldwide during the past 25 years have taken between 9.5 and 16 years. The brief project length can therefore be viewed as top of its class. In addition, the project remained within its planned budget of just under 21 mil. EUR after adjusting for inflation.
The High-Field Magnet represents yet another first-class instrument that is being connected to the neutron source for the final BER II support period. Completely new kinds of experiments become possible that will open up access to new science, such as researching superconduction and magnetic phase transitions in solid-state materials, for example.
- Spintronics at BESSY II: Real-time analysis of magnetic bilayer systemsSpintronic devices enable data processing with significantly lower energy consumption. They are based on the interaction between ferromagnetic and antiferromagnetic layers. Now, a team from Freie Universität Berlin, HZB and Uppsala University has succeeded in tracking, for each layer separately, how the magnetic order changes after a short laser pulse has excited the system. They were also able to identify the main cause of the loss of antiferromagnetic order in the oxide layer: the excitation is transported from the hot electrons in the ferromagnetic metal to the spins in the antiferromagnet.
- Electrocatalysts: New model for charge separation at the solid-liquid interfaceHydrogen is at the heart of the transition to carbon neutrality, as both an energy carrier and a reagent for green chemistry. However, large-scale production of hydrogen via electrolysis, as well as the production of many other chemical products, requires significantly cheaper and more efficient catalysts. A precise understanding of the electrochemical processes that take place at the interface between the solid catalyst and the liquid medium is highly useful for developing better electrocatalysts. In the journal Nature Communications, an European team has now presented a powerful model that determines charge separation at the interface, the formation of the electric double layer and local electric potential variations, and the resulting influence on the catalytic activity.
- Environmental Chemistry at BESSY II: Radicals in waterwaysHow do radicals form in aqueous solutions when exposed to UV light? This question is important for health research and environmental protection, for example with regard to the overfertilisation of water bodies by intensive agriculture. A team at BESSY II has now developed a new method of investigating hydroxyl radicals in solution. By using a clever trick, the scientists gained surprising insights into the reaction pathway.