Quasioptical design for an EPR spectrometer based on a horizontal-bore superconducting solenoid

We describe a novel high-frequency electron paramagnetic resonance (HF-EPR) spectrometer design based on a horizontal-bore superconducting solenoid. D esigns for components of a quasioptical HF-EPR spectrometer operating with a horizontal-bore 7.85 T solenoid are discussed. A rigid concentric tube co nstruction permits precise placement and control of the optical elements in the magnet bore. A mechanically coupled, sliding optical table bearing the quasioptical bridge is another essential feature of the design. The horizo ntal configuration greatly improves optical alignment as well as physical a ccess to the sample area compared to existing vertical-bore instruments. As a result, the minimum spin concentration that is detectable with an inexpe nsive room-temperature diode is comparable to the lowest values reported fo r aqueous samples in vertical-bore magnets using high-sensitivity detectors .