Based on the Standard Type, the portable type Ultra-low Concentration UV-DOAS Gas Measurement Optical Module reduces the volume of spectrometer and cancels the optical fiber, which makes the module more integrated and compact, and is more suitable for the development of portable instruments.

When the UV-Vis light of continuous spectrum passes through the target gas- in the gas cell, light of specific wavelength will be absorbed by the Target gas. The absorption (absorbance) of light is proportional to the concentration of the target gas. An empirical relation curve between the laboratory calibrated absorbance and the concentration of the sample gas is established by spectral analysis and chemometrics methods, then the concentration of the target gas can be calculated in real time according to the absorbance of the sample gas.  

LYDOAS UV-DOAS gas measurement module adopts a new type of multi-reflection gas chamber designed by LaoYing. After multiple reflections by the concave reflector in the gas chamber, the incident light finally converges to the light outlet. Since the light beam is reflected by reflectors fixed at both ends of the gas chamber the chamber wall is not involved in the light reflection, thus avoiding signal drift, sensitivity loss, etc. caused by aging of the gas chamber with traditional inner wall and ensuring the optical path stability in long-term use. The multi-reflection technique can achieve both small size and long optical path at the same time, and the optical path can be customized according to application requirements.

Note: The concentration in the table is the mass concentration under the standard state (temperature 273.15 K, pressure 101.325 kPa).