Low frequency NMR polarimeter for hyperpolarized gases

An inexpensive and self-contained apparatus for pulsed NMR at 30-250 kHz is described. The intended application is monitoring of the spin polarization of rare gas nuclei in a laser-polarizing apparatus in fields of order 30 G. In addition, the device provides a convenient method for following the polarization decay during storage and transport. Some of the features are a flexible pulse generator, splitting of transmitter RF cycles by the RF gate, a Q switch, and a wide range of receiver gains.