Simple and Sensitive Magnetic Resonance Spectrometer Using Thermal Detection and Square Wave Frequency Modulation

Abstract

The special features of this spectrometer are square wave frequency modulation and thermal detection. The modulation results from switching the microwave source between two eigenfrequencies of the cavity, obtaining pulsed frequency modulation without amplitude modulation in the microwave field. This technique is in many respects superior to the conventional static field modulation and has comparable noise suppression. The thermal detection is based on resistance modulation of a silicon monocrystal plate in contact with the sample and constitutes a very sensitive detection method at low temperatures.