Study On Wide-spectrum High-resolution Fast Detection Technology Of Atomic Emission Spectrometer

Atomic Emission Spectrometry(AES)is widely used in scientific areas like physics,biology and chemistry.With the advance of science and technology,higher requirements have been demanded for the sensitivity,the spectral range and the speed of the atomic emission spectrometry instrument.But there exist irreconcilable conflicts between high resolution and wide spectrum in a grating spectrometer.For now,most of the existing atomic emission spectrometers detect signals of different wavelengths by setting up multiple gratings and single-point detectors,which can not fundamentally solve the problems including low speed and narrow spectrum range.Thus it can't meet the demands of quick detections with high resolution and wide spectrum range at the same time.The high-speed detection techniques used in atomic emission spectrometers with wide range and high resolution can significantly improve the detection of spectral range and spectral resolution,which is of great value in the studies and researches on chemical elements.Because of the mutual restriction among wide range,high resolution and quick detection in atomic emission spectrometers,solutions are needed to widen the spectral range,increase the resolution and quicken the section speed,and it is of key importance to look deeper into core techniques about the designing,wide-spectral-range scanning,quick detection and distant transmission of the optical system of the high-resolution spectrometer.This paper proposes an overall designing scheme for atomic emission spectrometers,and great emphases are laid on how to optimize the optical system design of the spectrometer.Based on the relative theories on atomic emission spectrometers and optical aberration,analyses are made about the factors affecting the spectral resolution,spectral range and detecting speed of a spectrometer.Analyses are also made about those affecting the resolution of a spectrometer based on the basic theories on grating spectrometers and optical aberration,and derived equations are introduced to explain how the devices in the spectrometer affect the resolution.The incident slit width required in a spectrometer can be calculated by matching the pixel resolutions,considering the parameters of the photo detector and the field diaphragm;an angle displacement platform are used to rotate the grating in order to scan with the desired wide spectral range;comparisons are made between the performances of photomultiplier tube(PMT)and charge coupled device(CCD),and based on the result CCD is the better choice for quick detection.Then the overall designing scheme is introduced for quick-detection atomic emission spectrometers with wide spectral range and high resolution.The wavelength of the center and the edges cannot achieve high resolution simultaneously,so an initial structure design method of the dispersive system of spectrometer is proposed.An optimized grating dispersive optical system can be designed with this method.After a simulation,the RMS value of the full field of view between 200 nm and 1000 nm is smaller than the two detector pixel size of 32?m,and the wavelength difference of 0.01 nm can be distinguished in different bands.This resolution meets the design requirements.According to the optical principle of double telecentricity of object image,a fore-optics for atomic emission spectrometer is introduced,which the source signal of the atomic emission spectrometer is transmitted to the incident slit of the spectrometer at a magnification of 1:1,and thus long-distance transmission(1400mm)of light signals can be realized in atomic emission spectrometer.