The China Advanced Research Reactor (CARR) is a high-flux and multipurpose research reactor, located at the campus of China Institute of Atomic Energy(CIAE) in Beijing. It is a tank-in-pool inverse neutron trap type reactor with a power of 60MW. The peak flux in a heavy-water reflector is about 8.0×10^14 n/cm2/s. It has 9 horizontal beam tubes and 25 vertical channels. A liquid D2 cold neutron source will be equipped in 2015. Cold neutrons would be transferred to the neutron guide hall (30×60 m2) via 4 neutron guides. CARR went first critical on May 13th 2010 and reached the full power for 72 hours on March 13th 2012. Now it is waiting for the official permission to start the regular operation.
Fig. 1. CARR at the Campus of China Institute of Atomic Energy
As one of main applications of CARR, neutron scattering laboratory in CIAE is in charge of neutron scattering and neutron imaging instruments, which are located in the 38×38 m2 reactor hall and the 30×60 m2 cold neutron guide hall, as illustrated in Fig.2. At the first phase, cooperating with Peking University, Institute of Chemistry of Chinese Academy of Sciences (CAS), Institute of Physics of CAS, Juelich center in Germany and the partner from Sweden, nine instruments are complete and under commissioning, which are a High Resolution Powder Diffractometer (HRPD), a High Intensity Powder Diffractometer (HIPD) a Residual Stress Diffractometer (RSD), a texture diffractometer (TD), a four circle diffractometer (FCD), two Triple Axis Spectrometers (TAS), a reflectometer (RF), a Small Angle Neutron Scattering instrument (SANS) were constructed. At the same time, some sample environments, such as cryostat (4 K to 500 K), furnace (room temperature to 1800K), high pressure (10GPa), Magnet (7 T, 1.6 K to 300K) , are also equipped. At the second phase, a Cold Triple Axis Spectrometer (CTAS) and a Multi Axis Crystal Spectrometer (MACS) in cooperation with Renmin University of China, a Engineering Neutron Diffractometer (END) in cooperation with Central South University, a Thermal Neutron Imaging (TNI) and a Cold Neutron Imaging (CNI) are being designed and under construction. Furthermore, the third phase instrument proposal was handed in and under review procedure.
As an open user center CIAE makes the facilities at CARR available to scientists from all over the world, the users are also welcomed to involve building their own instruments at CARR. Till now three institutes and three universities from the world involve the instrument construction. At the end of 2013, the China Advanced Research Reactor run 42 hours with 20 MW. During the reactor operation, all of the instruments around the reactor were optimized and got their diffraction patterns, even phonon dispersion curves. The experimental results look quite promising. So the instruments at CARR are ready and will come to serve users soon!
Fig.2. Layout of the Neutron Scattering Instruments at CARR
