Study On Nondestructive Testing Based On Raman And Infrared Spectroscopy

Detection technology based on optical spectrum analysis,which is non-contacting,non-destructive,safe and fast,has broad and important civil and military applications.In military applications,we obtained the pressure characteristics of new ammunitions by Raman spectrum measurement and first-principles calculation.In civil applications,for the request of remote detection of hot gases and detection of dangerous chemical gases,we have built a gas pool and investigated the infrared spectra of CO2,which provides basis for infrared-spectrum-based early-warning.Based on the measured Raman spectrum of RDX grains and first-principles calculations,it is found that the internal pressure in RDX grains is linearly dependent on the pressure induced Raman spectrum shift.This linear relation can be calibrated in the laboratory,based on which the internal pressure in the irregular-shaped RDX can be retrieved from the difference of the Raman spectrum of the target and the standard sample.In this way,the non-destructive measurement of the internal pressure of RDX can be realized with merits high sensitivity and good consistency,etc.To realize the early warning of fire and toxic gases,it is necessary to build a library of the infrared(IR)spectra of the gases under different concentrations,and temperatures,which can be used to retrieve the properties of the target gases by comparison of the measured IR spectra with those in the library.In order to measure the IR spectra of gases under different concentrations and temperatures,we have made a gas pool.The gas is introduced into the pool and the concentration and temperature can be controlled,respectively.With this gas pool,we are able to measure the IR spectra of gases and the highest temperature available is 350 ? Bruker IFS125HR Fourier transform IR spectrometer with Ultra high resolution is employed to measure the IR spectrum of CO2 under different concentrations and temperatures,the characteristics of its fine spectrum and spectral self-absorption effect is observed,which leads to a preliminary library of CO2 IR spectra.