The Bonn polarized target NMR-system

The Bonn frozen spin target is used for meson photoproduction experiments in combination with the facility PHOENICS at ELSA. The maximum polarization field of 7 T is provided by a superconducting solenoid. For electron scattering experiments a target apparatus which uses a superconducting 4 T magnet in a Helmholtz configuration is employed. For dynamic nuclear polarization of protons or deuterons various microwaves sources with frequencies of 70 GHz, 98 GHz or 140 GHz are available. Ammonia, butanol and lithium hydrids are used as target materials. in part of the polarization detection system is the so-called Liverpool nuclear magnetic resonance module, which ensures a high flexibility for the polarization measurements of different nuclear species, e.g. 15N at 2.5 T (fL=10.8 MHz) and protons at 50 T (fL=213 MHz).