First Phase Neutron Sattering Instrumentation at the China Advanced Research Reactor

After 50 years of service for the Research & Development in neutron science and technology, the Heavy Water Research Reactor (HWRR) (maximum power 10 MW) at China Institute of Atomic Energy (CIAE) was shut down in 2007. The 60MW China Advanced Research Reactor (CARR) at CIAE has taken over this role, which has reached the first criticality in May, 2010. It is a tank-in-pool type reactor using a D2O reflector for inverse neutron trap, and the designed optimal undisturbed thermal neutron flux is 8×1014 n/cm2•s. The reactor experiment hall houses a set of instruments connecting to 7 horizontal thermal neutron beam tubes, two of which are dual beam ports. Additionally, cold neutrons produced by a liquid hydrogen cold source are transported via 4 guide systems to the 30 × 60m2 guide hall, where a suite of scattering instruments are placed.

Guide hall

CARR is devoted to fundamental and applied research, of which the Neutron Scattering Laboratory (NSL) is responsible for neutron scattering and radiography research programs open to users in China and abroad. Ten neutron scattering instruments will be installed in the first phase: a high resolution powder diffractometer (HRPD), a residual stress diffractometer (RSD), a triple-axis spectrometers (CIAE-JCNS-TAS), a four-circle diffractometer (FCD), a texture diffractometer (TD), a thermal-neutron radiography station and another triple-axis spectrometers (IOP-CIAE-TAS) will be placed in the reactor experiment hall. A small-angle scattering instrument (SANS), a horizontal sample-geometry neutron reflectometer (NR), and a cold-neutron radiography station will be installed in the guide hall.

Reactor Hall

The latest development of neutron scattering instruments at NSL-CARR is briefly described as follows. HRPD is a new instrument entirely designed and built at CIAE. Currently, all the key components, including the sample table, detector arm, monochromator and the data-acquisition system, have been completed and arrived at CARR. The assembling and alignment of the components are under way. RSD is built in collaboration with Studsvik in Sweden; some key components such as the sample table and collimators were transferred from Sweden. The shielding drum, monochromator and its attitude adjusting table, and the PLC movement control system are designed by CIAE. All the components have been assembled and installed, and the instrument is under testing currently. HRPD and RSD will be the first two instruments to be commissioned at CARR. CIAE-JCNS-TAS, FCD and TD are imported from the Neutron Scattering Center of Juelich, Germany (FZJ) under Cooperation Agreement between FZJ and CIAE. The reassembling of CIAE-JCNS-TAS is completed and waiting for neutrons for further beam line alignment and electronics and mechanics adjustment. Some key components of FCD and TD, including the monochromator shielding, first collimator, beam monitor are under construction. The IOP-CIAE-TAS is co-developed by the Institute of Physics of CAS and NSL-CARR with the technical support from FRM II (Germany).

Layout of the neutron scattering instruments at CARR

The 30m SANS and the NR are co-developed by the Institute of Chemistry of CAS and NSL-CARR with gracious assistance from NIST (US). As major funding of the two instruments is provided by the Ministry of Science and Technology of China, which will be run in a Participating Research Team (PRT) user mode. At present, both instruments have been installed completely and are under test.

From the outset, NSL has consulted and worked closely with the international neutron community. In 2007, the first meeting of the International Advisory Committee for NSL-CARR on neutron science and technology and management was held in Beijing, China. The recommendation of this Committee has in part led to the funding by CIAE for the two radiography stations and a new user building.