A target for producing polarized Na-21 by optical pumping

We describe a target used to produce Na-21, a 22.5 s half-life positron emitter, in 2.5 bar of Ne-20 gas. The Na-21 was subsequently polarized in situ using a pulsed dye laser, with a maximum nuclear vector polarization \[J]\ = 0.70(2). The Ne-20 gas also serves as a buffer, increasing the diffusion time to the target chamber walls to about 12 s. Integrating over this time interval, the target gives an average activity of greater than 10(6) s(-1) with \[J]\ = 0.62.