Optimization of dynamic nuclear polarization system for contrast variation in small angle neutron scattering

Noda, Yohei

We have applied proton spin polarization to contrast variation method in small angle neutron scattering (SANS) study. Especially, we succeeded in applying this technique to silica-filled rubber, which is not easily fabricated in a deuterated form. At the last SANS experiment, degree of proton spin polarization (i.e., the population difference between up and down spins) was limited (26 % at maximum). It is essential to enhance proton spin polarization further in order to modify scattering contrast widely and separate partial scattering functions presicely. Toward this, as a result of inteisifying microwave irradiation, we finally enhanced proton spin polarization up to 50.8% for TEMPO-doped polystyrene. The achieved result will improve performance in SANS experiment at J-PARC.