Proton Polarization at Room Temperature wih Laser and it's application

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We have polarized protons in molecular crystals of naphthalene doped with pentacene using a dye laser in 3 KGauss at the temperature higher than 77 Kelvin. In this new method electrons are excited to high singlet states with the laser beam, where the spin-orbit interaction causes the transition from singlet states to intermediate triplet states. The populations of the Zeeman sublevels of the lowest triplet states with Z-components of the total electron spin+1,0, -1 are 12,76 and 12% respectively. During the lifetime of the triplet state (some 20 microsec) microwave irradiation occurs and the external field is swept simultaneously to transfer the population difference of electrons between two Zeeman sublevels to the proton polarization by means of the integrated solid effect. Electrons on the triplet states decay to the ground state, where the proton spin remains polarized for a long time.We have tried to polarize protons in naphthalene doped with pentacene (0.01 mol%) with a high-power pulsed dye-laser (lambda=590-605nm) and got about 34% polarization at liquid nitrogen temperature. The enhancement factor corresponding to this value is 8*10^4. The relaxation times of protons are about 1,000 and 160 minutes in hte field of 3KG and 7G respectively. The method is applicable to the wide fields of spin physics. Since the target has no heating problem and no serious problem of radiation damage, it can be used for high-intensity beams of hadrons and electrons. Secondly, the target is useful for experiments with very low-momentum charged particles, since the necessary magnetci field to keep the polatization is extremely low.