Measurement of spin-exchange and relaxation parameters for polarizing 21Ne with K and Rb

Hyperpolarized K-3He comagnetometers have been used for tests of fundamental physics and inertial rotation sensing. These experiments will demonstrate increased sensitivity if the 3He buffer gas is replaced with 21Ne. We measure the parameters necessary to realize implementation of an alkali-metal–21Ne comagnetometer for two promising alkali-metal species, Rb and K. The spin-exchange rate constant for K with 21Ne and Rb with 21Ne are measured using two different methods. We also make the first measurement of the K-21Ne contact spin interaction. Measurements for the Rb-21Ne contact spin interaction, as well as the spin-destruction coefficients for 21Ne with both alkali-metal species are consistent with previous measurements. Additionally the quadrupolar spin-relaxation rate of 21Ne is measured. Finally, the feasibility of utilizing polarized 21Ne for operation in a comagnetometer is discussed.