The Research Of ESR Signal Acquisition Technology

Electron spin resonance (ESR) is a powerful tool to explore the micro-physical structure of paramagnetic, Its research object is material which have unshared pair electron. Such as atom and molecular which has an odd number of electron, and ion that has not been filled of in the electron shell, radical which is produced by radiation and semiconductors, metals and so on. Through research about the resonance lines, we can get the unshared electronic state of molecules, atoms and ions; and its surrounding environment information. In order to obtain the information on the structure of matter and chemical bonds. So electron spin resonance is an important modern physics experimental technique。It had been widely applicabled in physics, chemistry, biology, medicine and other fieldsRadio-frequency electron spin resonance experiment is an important classical physics experiment instruments. AT present, all colleges and universities have offered the electronic spin resonance experiments courses and they use the traditional spin resonance device to do the experiments. Its principle is to capture the resonace signal by scanning the magnetic field and transport the electron spin resonance signal to the oscilloscope to watch. The research of this topic is mainly to make further improvements to traditional electron spin resonance instrument and in the sweeping field methods of the radio-frequency electron spin resonance instrument we will do innovation.The traditional field sweep method of radio frequency electron spin resonance instrument is superpose the alternating magnetic which is produced by connecting the 50Hz simple alternating current mains supply to the field sweep coils(through the transformer).By this methods, we can observe the resonance signal. Its biggest drawback is susceptible to frequency interference, and thus measurement accuracy is not high enough. This paper solved this problem by changing the sweep field signal.I researched a lot of different signal generation methods,and choose MCU to control the output frequency of 100Hz to 300Hz variable sweep triangular waveform current,let it scan the magnetic field. This method can avoid the frequency interference and improve detection sensitivity, and to make the resonance spectral line have a better resolution.The subject adopts the designed method that combination the hardware and software. According MCU control theory, combined with the basic structure of CHMM₁ electron spin resonance instrument that experiments used.I designed MCU control output triangular wave signal, pass through power amplification to drive sweep field coils to scan the magnetic field and successfully observed the resonance signals of the object measured,and finally completed the purposes and requirements of the topics of research.