A portable EPR system for the absolute polarimetry of noble gases

A simple and portable electron paramagnetic resonance (EPR) system has been developed for the absolute polarimetry of noble gases polarized by spin-exchange optical pumping. By using modern digital technology together with software implementation of phase-sensitive detection and feedback control, the new system has become much more compact than the conventional EPR apparatus and can be easily transported anywhere. The main components of the new EPR system are a computer and a PC-based oscilloscope with a built-in function generator. The raw signal data is processed in real time by a computer, which offers great flexibility to the new system. By modifying the data-processing algorithm, it can be customized and applied to other scientific and engineering measurements that utilize phase-sensitive detection.