The general purpose powder diffractometer at CSNS

The general purpose powder diffractometer (GPPD) at the China Spallation Neutron Source (CSNS) is designed to be a flexible and versatile instrument for a wide range study of crystallographic and magnetic structures. Decoupled poisoned hydrogen moderator is used as its neutron source. The distance between the sample and moderator is 30 m. Focusing neutron guide and an interchangeable neutron guide/collimator system are employed to transport neutron. The instrument can be optimally configured for individual experiments with desired resolution. There are three detector banks (high-angle, 90 degrees, and low-angle), covering a wide d-spacing from 0.05 to 28.11 angstrom. The best resolution will be better than 0.2% at high angle detector bank. The neutron flux at the sample position will be at the order of 10(7) n/s/cm(2). Now the construction of GPPD main building and fabrication of most key components have been done within 2016. The off-line integrated test with related system is going on well. The project will be completed in the end of March 2018, as one of the three day-one instruments for CSNS.