HIGH PROTON POLARIZATION, up to 32%, has been achieved at liquid-nitrogen temperatures (77 K) and with modest 0.3-Tesla magnetic fields in an experiment at Kyoto University in Japan. Among a proton's attributes is the orientation of its intrinsic spin; this directionality can come into play when the proton interacts with the spins of other particles or with a radio frequency field. For comparison, proton polarization levels in MRI medical imaging is a paltry .0003% (still good enough for spotting tumors) using room temperature and magnetic fields typically of 1 Tesla (10,000 gauss). Targets for particle physics using accelerators can achieve polarizations of up to about 70% but even higher fields (2 or 5 T) are needed as well as low liquid-helium temperatures (typically 0.3 K).

In the Kyoto experiment, the electrons in pentacene (an aromatic organic molecule chain) are polarized optically with a laser beam. Next, microwaves force the polarization to be transferred to protons in the molecules. The researchers (M. Iinuma, 011-81-824-24-7373, iinuma@photon.hepl.hiroshima-u.ac.jp) suspect that their approach will find applications in particle physics (where targets polarized in smaller fields and warmer temperatures would permit the detection of slower charged particles amid high intensity beams) and in chemistry/biology (where the new method provides higher sensitivity than the existing NMR).

Polarized protons would be portable in a small box for more than 3 hours at almost zero magnetic field. The new polarization method should also benefit MRI imaging (where high polarization can improve spatial resolution of pictures ), the task of transfering spin to normally-hard-to-detect C-13 atoms, and NMR-based quantum computing (wherein information storage and processing are vested in spins). The Kyoto physicists, through various improvements, hope to extend their method to room temperatures. (Iinuma et al., Physical Review Letters, 3 January /pnu/2000/; Select Article; figure at www.aip.org/png)