New technique for improved low-temperature SQUID NMR measurements

A description of the technique used for performing a variety of SQUID NMR measurements in fields varying from 3.7 to 309 G is presented. Pulsed NMR, cw NMR, adiabatic fast passage, and static susceptibility measurements have been made on liquid 3He, using the same detection system, in the temperature range 1.2K–2mK. The spin-lattice relaxation times varied from 100 s at 1 K to as fast as 0.26 ms at 2 mK. The spin–spin relaxation times varied from 3×10−5 s in 309 G to nearly 3×10−3 s in 3.7 G.