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Today, we successfully completed in-beam commissioning polarised neutrons using our Metastable-Exchange Optical Pumping System, and associated polarised-neutron infrastructure, on the 6th instrument at OPAL, the Taiwan-funded SIKA cold-neutron 3-axis spectrometer.
The latest test on SIKA yields 95% neutron polarisation at 20% transmission through a polarised 3He cell for 14.8 meV / 2.35 Å neutrons. The result agrees with what is expected from the selected setup. With this test, we have fulfilled the final requirement of neutron tests on all 6 instruments supported by the Polarised 3He project. Many people in the Bragg Institute and in ANSTO have gone above and beyond the call of duty to achieve this success, and together we have fulfilled many goals within a tight time frame:
(1) Commission a complex 3He polarising station;
(2) Commission an array of associated polarised 3He equipment;
(3) Construct and test the infrastructure for all 6 specified OPAL instruments: PELICAN, PLATYPUS, QUOKKA, SIKA, TAIPAN, and WOMBAT;
(4) Carry out neutron tests to verify polarised 3He reaches the desired performance in neutron polarisation and transmission on all 6 instruments.
While we have fulfilled the specific project requirements, there is still much to do, fully and seamlessly to operate the equipment for full polarisation analysis (controlling magnetic field environment, accommodating different sample environment, etc.) Full polarisation analysis is already available to users on WOMBAT and TAIPAN. We are now aiming to have polarisation analysis using polarised 3He on PELICAN, PLATYPUS, QUOKKA, and SIKA available in 2015, and to expand the use of polarised neutrons in conjunction with different sample environments.
Congratulations to Hal Lee and Tim d'Adam, who led and implemented this effort and also to the Institut Laue-Langevin (in Grenoble, France) who provided the whole system and the initial set of cells, along with lots of advice and collaborative help.
Published: 29/11/2014