通过对T型光声池内模式分布、温度分布以及边界条件的分析,建立了共振频率与温度关系的数学模型。分析了品质因子温度的关系及其影响因素。在-100~0℃范围内对光声池的温度稳定性、共振频率、系统灵敏度进行了测量和分析,结果表明,共振频率随温度的降低而减小,系统的灵敏度受温度影响较小。在-100~0℃范围内对不同浓度CO2探测的最小浓度范围为3.2~5.2mg.m-3,说明该系统可用于痕量气体探测;克服了麦克风低温下灵敏度降低的问题,为低温下进行痕量气体探测提供了一种新的研究方法。
A homemade low-temperature T shape photoacoustic system(PAS) in the range from 0 to-100 ℃ is well established.The mode distribution,the temperature dependence of the resonant frequency,Q-factor and the sensitivity of the PAS were investigated.The measurement of the carbon dioxide in the range from 0 to-100 ℃ showed that the system can be used in trace gas detection under low-temperature.The results show that the PAS can be used to study the atmospheric molecules continuous absorption at low-temperature.