Electron spin resonance, also known as electron paramagnetic resonance, refers to the phenomenon that a resonance transition between magnetic energy levels occurs when the electron spin magnetic moment is impacted by an electromagnetic wave of specified frequency in a magnetic field. This phenomenon can be observed in paramagnetic substances with unpaired spin magnetic moment (i.e. compounds containing unpaired electrons). Thus, electron spin resonance is an important method to reveal the microstructure of a substance by probing the unpaired electrons in the material and analyzing how they interact with surrounding atoms. This method has high sensitivity and resolution, and it is a nondestructive detection technique for analyzing the internal structure of materials. This technique has been widely used in physics, chemistry, biology and medicine, and other fields of study.
This apparatus of electron spin resonance in microwave band is upgraded from an old version by adding a microwave frequency meter to measure microwave frequency and a digital Gauss meter to accurately measure resonance magnetic field. It can be used for modern physics experiments, as well as R&D applications in research laboratories. Using this apparatus, the following experiments can be conducted:
1. Observe the electron spin resonance phenomenon of a standard DPPH sample.
2. Measure working frequency and estimate the required constant magnetic field under resonance conditions.
3. Measure constant magnetic field and calculate the g-factor of DPPH sample under resonance conditions.
4. Adjust sample cavity length, measure positions of resonance points, & calculate waveguide wavelength.