The present invention relates to a method and apparatus for hyperpolarizing a noble gas by spin-exchange optical pumping which includes a polarization cell containing the noble gas, a primary alkali metal and an auxiliary alkali metal. The polarization cell is illuminated with radiation to optically polarize the primary alkali metal. This enables spin-exchange interaction between the primary alkali metal, the auxiliary alkali metal and the noble gas resulting in a hyperpolarized noble gas.