Developing Polarized neutron capability at the China Spallation

中国散裂中子源 Developing Polarized neutron capability at the China Spallation Neutron Source Zachary Buck PSTP Knoxville, TN September 26 th, 2019

Table of contents 1. Overview of China Spallation Neutron Source (CSNS) 2. Polarized Neutron at CSNS • SEOP 3 He neutron spin filter system • Current beamlines and implementation 3. Future development of CSNS polarized neutron

Intro to CSNS Beijing v Joining a few others to make it the 4 th spallation neutron source worldwide China Shanghai Hong Kong v Located in the city of Dongguan in Guangdong Province, China Guangzhou Dongguan v Population in Dongguan: 8. 2 million CSNS v Tropical climate Shenzhen Hongkong Macao The “Big Bay” area

China Spallation Neutron Source (CSNS) Site

Intro to CSNS http: //english. ihep. cas. cn/csns/doc/1959. html

Polarized Neutrons at CSNS • Developing Polarized Neutron capabilities for CSNS • Polarized 3 He (Primary polarization method) • Supermirror and Heusler Crystal (Supplementary methods) • Deploying Polarized Neutrons onto existing and future beamlines • Polarized reflectometer, SANS and Powder Diffractometer • Future beamlines are investigating polarized option and design • Future of Polarized Neutrons at CSNS • Complete R&D capability for a polarized neutron beamline • Polarization analysis, polarization manipulation, magnetic field simulation capability

SEOP 3 He neutron spin filter at CSNS q Isolated Pumping station in laser lab at the target station for easy delivery. q Filling station to make new 3 He cell with various parameter to fit different beamline requirement. q Transportation cart to allow off-situ transfer and monitoring 3 He polarization on beamline q Integrated control system for heating, signal processing and interlock. Linked with public notification system (Wechat) q In-situ system in development Current off-situ system

SEOP 3 He neutron spin filter at CSNS Oven and main coil Current source and control panel Laser and Optics Vacuum system and RGA Gas mixing system and pressure gauge N 2 and 3 He gas through purifier

Implementing Polarized Neutrons onto current beamlines v Multiple purpose Reflectometer (MPR) http: //english. ihep. cas. cn/csns/doc/2038. html v General Purpose Power Diffractometer http: //english. ihep. cas. cn/csns/doc/2037. html v Small Angle Neutron Scattering http: //english. ihep. cas. cn/csns/doc/2039. html

Polarized Neutron at the MPR beamline q Replacing supermirror analyzer after the sample q Improving overall polarization and beam size q Both off-situ and in-situ

Polarization Testing Station q BL-20 at the CSNS (8 m long) q Peak intensity 2. 4 Å q 2 Å - 8 Å wavelength band v Test station of polarized neutron devices and setups (Polarizer, Analyzer, guide field, flipper, spin transportation device, etc. ) v Research and develop new polarized neutron experiment method

Future of Polarized Neutrons at CSNS q Implement polarized neutron for future beamlines at the CSNS site v Non-elastic scattering, neutron imaging, Engineering Diffractometer, etc. q Developing better polarized neutron experimental capabilities at the spallation source v Improving polarization and developing customized polarization instrument q Developing new polarized neutron methods for time-of-flight neutron v Neutron polarization manipulation for time-of-flight neutron v Neutron polarization analysis for time-of-flight neutron

Conclusion q China Spallation Neutron Source is a new spallation source among the world, currently under rapid development q At CSNS, we are working on developing polarized neutron capability to implement on the current and future beamlines q Future development at CSNS involves better polarization capability and new polarized neutron method for time-of-flight neutron

Polarized Neutron Team Thank you for your attention This work was supported by the National Nature Science Foundation of China (No. 11875265), the Scientific Instrument Developing Project of the Chinese Academy of Sciences (3 He based neutron polarization devices)，the Institute of High Energy Physics, and the Chinese Academy of Science