The Atomic Beam Source creates a jet of cold Helium-3 gas and passes it through a series of quadrupole magnets that focus one spin state and defocuses the other. The defocused atoms are pumped away, leaving a highly polarized beam.
A suite of carefully designed magnetic coils (Need figure from Chris C.) orients the spins in the correct direction and maintains the polarization through the MSE layers and into the 30 milliGauss holding field.
The beam is directed into a volume of liquid helium. By slightly raising the temperature of this volume the Helium-3 atoms can be quickly transported to the measurement cells – an effect known as “heat flush”. This effect was imaged using a neutron beam
At the end of a measurement cycle this process must be reversed; by cooling a small volume of Helium the somewhat depolarized Helium-3 can be pulled out of the measurement cell. We isotopically purify the Helium in our measurement cell to one part in 1012 every measurement cycle!
Oak Ridge National Laboratory is managed by UT-Battelle LLC for the US Department of Energy