Observation of a 96% proton polarization in irradiated ammonia
Abstract
Using dynamic nuclear polarization we obtained proton spin-polarization values of +(95+/-5)% and -(97+/-5)% in radiation-doped frozen ammonia. Moreover, the polarization reached 90% in about 25 min. These results were obtained using our new 1-K high cooling power 4He evaporation refrigerator operating in a 5-T magnetic field with 140-GHz microwaves. This unexpectedly large and rapid polarization coupled with about 1 W of cooling power should allow significant improvements in high-energy spin-physics experiments and may have some physics interest in itself.
- Publication:
-
Physical Review Letters
- Pub Date:
- May 1990
- DOI:
- 10.1103/PhysRevLett.64.2627
- Bibcode:
- 1990PhRvL..64.2627C
- Keywords:
-
- 33.25.Hv;
- 29.25.Kf;
- 75.25.+z;
- Spin arrangements in magnetically ordered materials