Anyone entering the huge site of the ￥2.2bn (USD330m) China Spallation Neutron Source (CSNS) can be in no doubt it will be a major facility

The China Spallation Neutron Source expects first neutrons in October 2017. (Physics World)

for China once open to users in March 2018. Occupying 0.67km² of land in the hills some 30km south-east of Dongguan, the CSNS will be one of the largest scientific facilities in China. Indeed, it is so large that a new branch of the Institute of High Energy Physics in Beijing has been opened on site with 400 positions, 240 of which have already been filled.

While there are nuclear reactors in China that provide neutrons for researchers – such as the China Advanced Research Reactor in Beijing – the country has previously lacked a spallation neutron source. The CSNS features a 200m-long 80MeV linac that accelerates protons which are fed into a 1.6GeV 238m-circumference synchrotron. The protons are fired into a solid tungsten target that can produce a 100kW beam of neutrons with 25 bunches of particles released every second. The facility has room for a total of 20 instruments.

Construction of the CSNS began in 2012 with first neutrons set for October 2017. Half of the money to build the CSNS has been provided by the local Guangdong government, with the rest from central government. “The local government wanted a big science project as there is not one in south China,” says Ma Li, standing vice chief manager of the CSNS. “The CSNS was a good option.”

The first phase of the CSNS is expected to contain three instruments that already have funding – a powder diffractometer, a small-angle neutron scattering instrument and a reflectometer. Two more instruments are in the pipeline including a high-pressure powder diffractometer and an engineering diffractometer, which is being built in collaboration with the ISIS Neutron and Muon Source in Oxfordshire, UK.

One challenge for China is that its neutron community is relatively small. This is being addressed via training schemes to boost the numbers of scientists and students who will be able to use neutrons for their research. In 2013 the Chinese Physical Society also set up a neutron scattering group to help in this endeavour.

With just a handful of instruments initially, CSNS officials are already addressing the expected rise in demand for more by submitting a funding proposal to the Chinese Academy of Sciences. These second-phase instruments will likely focus on the dynamics of materials and include spectrometers. “We want to attract users to build instruments at the CSNS,” says Li.

Plans are even afoot to boost the power of the neutron beam to 500kW by increasing the energy of the linac to 250MeV using superconducting magnets. Space has also been allocated for a second target station that would vastly boost the number of instruments and produce neutrons with a different frequency suitable for experiments in the life sciences.(Physics World)