A neutron beam was successfully obtained at the China Spallation Neutron Source (CSNS) for the first time on 28^th August. This is a great milestone for the CSNS project, marking the completion of the main construction and the start of the test operation phase. As a national large scientific facility, CSNS has made outstanding achievements. The CSNS project should be fully completed and open to domestic and international users by 2018 as scheduled.

On the morning of 28th August, the target and instrument control room were packed with people, looking forward to witnessing this historic moment. CSNS staff had carefully prepared for the first production of the neutron beam, before Professor Chen Hesheng, CSNS project manager, gave the order. At 10:56, a proton beam pulse from the accelerator collided on the tungsten target for the first time. Two neutron detectors at the No.6 and No.20 beam lines, corresponding to two types of moderator, measured the neutron spectrum, which indicates the successful production of the neutron beam.

“The idea of building the CSNS in China was first proposed at the Xiangshan Science Conference in February 2001,” said Chen Hesheng, “The Chinese Academy of Sciences (CAS) has given CSNS a lot of support since 2006. We worked with more than 100 organizations all over the country, especially in producing equipment for the accelerator, target and instrument systems. We managed to overcome many technical problems and as a result, our equipment localization rate is over 96% and much of it has reached a world-leading level.”

The CSNS team has spent nearly 6 years on this project and witnessed many significant moments. The groundbreaking ceremony was held in October 2011. In October 2014, the Hˉ ion source, the first piece of accelerator equipment, was installed into the linac tunnel. In July 2017, a proton beam was successfully accelerated to 1.6 GeV in the rapid cycling synchrotron (RCS). Now, on August 28th, 2017, a neutron beam was obtained.

To produce the beam, the tungsten target was bombarded with a proton beam, which successfully drove neutrons from the nuclei of the target atoms. This shows that the design, fabrication, installation and commissioning of the accelerator and target station systems are complete, to a high level of quality and reliability.

The world's fourth pulsed spallation neutron source, CSNS has a wide range of applications in research areas like materials science, life sciences, physics, chemical industry, new energy and so on. CSNS will serve as a high-level scientific research platform, help improve national sustainable development, and fulfill the national needs. Also, CSNS will become a large research center in Guangdong Province. “It is certain that the CSNS, as a world-class comprehensive research base, will make great contributions to scientific innovation in the Guangdong-Hong Kong-Macao Greater Bay Area,” said Chen Hesheng in a recent speech.

CSNS is composed of a linac with a modest but upgradable energy of 80 MeV, a rapid cycling synchrotron (RCS) of energy 1.6 GeV, 2 beam lines, a target station with a solid tungsten target, and 3 instruments for the first phase including a General-Purpose Powder Diffractometer (GPPD), a Small-Angle Neutron Scattering instrument (SANS) and a multi-purpose reflectometer (MR). The GPPD is used as a tool to study crystal structure and the magnetic structure of materials. SANS is a very important neutron technique useful for probing structures from around 1 nanometer to more than 100 nanometers. It has a wide range of applications from studies of polymers to nanoparticles. The MR is for studying the surface and interface structure of materials through analyzing the reflected neutrons from the sample.