Structural Design And Simulation Analysis Of Main Magnet For Miniaturized NMR Instrument

Nuclear magnetic resonance(NMR:nuclear magnetic resonance)as a new measurement technology has the advantages of high detection accuracy,nondestructive sample,fast detection speed and so on.Has been widely used in medical imaging,oil exploration,material testing,food safety and other fields.However,there are many problems such as large volume,high cost of manufacture and maintenance,which restrict the use of NMR instruments.In order to improve the development of nuclear magnetic resonance(NMR)in daily civil detection,to reduce the cost of the instrument,to meet the technical requirements such as on-site detection and easy to carry,the study of the miniaturized NMR spectrometer is of great significance.The purpose of this paper is to study the small portable nuclear magnetic resonance(NMR)technology based on hogwash oil.The purpose of this paper is to develop a kind of small nuclear magnetic resonance instrument which can carry on the spot and sample the sample quickly.This paper is mainly the main magnet structure around the miniaturized nuclear magnetic resonance spectrometer is designed and simulated,and the magnet and select the RF coil,goal is to design a high magnetic field strength,good uniformity for the NMR detection of magnet structure.This paper mainly completed the following work:(1)this paper analyzes the development status of the domestic and international miniaturized nuclear magnetic resonance(NMR).(2)miniaturized NMR contrast to analyze a variety of main magnet structure,magnetic field and magnetic structure of permanent magnet has been calculated,so as to determine the size and the main magnet shimming adjustment reference.(3)the traditional type of magnet structure has been optimized by adding external magnetic yoke a loop increases the field strength,installing the optimized pole to eliminate the problem of end magnetic field is not uniform,in order to improve the uniformity of air gap magnetic field.(4)for the traditional permanent magnet material,the magnetic field intensity is low,the uniformity is poor,and the air gap field attenuates rapidly.This paper presents a scheme of using magnetic Haier Beck array(Halbach)as the main magnet.The magnetic field generated by the Halbach structure has the advantages of single polarity,high strength,uniform distribution and almost no magnetic leakage.According to this characteristic,a double nested Halbach main magnet is designed.(5)through the simulation of the main magnet model,the distribution of air gap field in the cavity of the main magnet is analyzed in detail.For the design of the main magnet of the nuclear magnetic resonance,a matched RF coil is selected.Finally,this paper summarizes the full text,and makes suggestions for the next step...