ISSN:
1573-7357
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract We have used the method of fractional distillation to produce an enhanced nuclear polarization of a saturated 3 He- 4 He mixture. For the experimental study reported in this paper, we have developed an all plastic distillation setup, which allows high 3 He circulation rates at low temperatures (18 μmol/s at 150 mK) up to the highest magnetic fields (22.5 T). The magnetization has been measured with a torque magnetometer. The nuclear magnetic relaxation time T1 of the 3 He- 4 He mixture was found to increase with the square of the magnetic field, indicating that T1 is dominated by surface relaxation. As a consequence, the enhancement of the magnetization due to the distillation process, which is amongst others proportional toT1 , increased also with the square of the magnetic field. At the highest field at 140 mK, a polarization of 8% of the 3 He- 4 He mixture has been obtained, 1.6 times the equilibrium value. Various ways to improve the set-up are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022541006442
