title: Room temperature hyperpolarization of nuclear spins in bulk.
abstract: Dynamic nuclear polarization (DNP), a means of transferring spin polarization from electrons to nuclei, can enhance the nuclear spin polarization (hence the NMR sensitivity) in bulk materials at most 660 times for (1)H spins, using electron spins in thermal equilibrium as polarizing agents. By using electron spins in photo-excited triplet states instead, DNP can overcome the above limit. We demonstrate a (1)H spin polarization of 34%, which gives an enhancement factor of 250,000 in 0.40 T, while maintaining a bulk sample (∼ 0.6 mg, ∼ 0.7 × 0.7 × 1 mm(3)) containing >10(19) (1)H spins at room temperature. Room temperature hyperpolarization achieved with DNP using photo-excited triplet electrons has potentials to be applied to a wide range of fields, including NMR spectroscopy and MRI as well as fundamental physics.
authors.affiliation: Department of Systems Innovation, Division of Advanced Electronics and Optical Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan;RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama 351-0198, Japan; and.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Tateishi
authors.affiliation: Department of Systems Innovation, Division of Advanced Electronics and Optical Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan; negoro@ee.es.osaka-u.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Negoro
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Nishida
authors.affiliation: Department of Systems Innovation, Division of Advanced Electronics and Optical Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan;
authors.forename: Akinori
authors.initials: A
authors.lastname: Kagawa
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Morita
authors.affiliation: Department of Systems Innovation, Division of Advanced Electronics and Optical Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan;
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kitagawa
mesh_terms: D004601:Elementary Particles; D060526:Magnetic Fields; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D013696:Temperature; D013816:Thermodynamics
keywords: pentacene; polarized target; quantum simulation; regioselective deuteration; sensitivity enhancement