Magnetic-field coils for metastability-exchange optical pumping, optical spectroscopy, and magnetic resonance of helium
Résumé
Optical pumping on the 2$^3$S-2$^3$P transition (1083 nm) of metastable $^3$He or $^4$He atoms is used for science and applications. Gas is usually enclosed in elongated cells with lengths ranging from several centimeters to several meters for efficient absorption, and good magnetic-field homogeneity is needed for reduced diffusion-induced relaxation. We describe a coil system providing a fairly uniform field of arbitrary direction over cell volumes, briefly discuss optimisation parameters and provide example of computed field maps.