Electron Spin Resonance (ESR), also known as Electron Paramagnetic Resonance (EPR), is a powerful analytical method to detect, analyze and determine the characteristics of unpaired electrons in a substance. It is clear that the state of electrons in a substance have a strong influence on its characteristics and functionality, so evaluation by ESR is becoming more and more important. Many types of substances, from electronic materials to catalysts to biological samples can be studied regardless of whether they are solid, liquid, or gas. A wide range of ESR techniques are possible using suitable attachments together with the basic instrument.
Recently, it has been widely accepted that even relatively few unpaired electrons in a sample can affect the function of the material, so lower detection limits (higher sensitivity) is required of ESR measurements. JEOL has achieved higher sensitivity by developing a low-noise Gunn oscillator for its new spectrometer, the JES X3 series.