激光干涉光谱仪器中的低温度响应舱体

Low Temperature Response Chamber in Laser Interferometer-Spectrometer

文章讨论了精密激光干涉光谱仪器的干涉腔环境温控技术。激光干涉测量技术是一种高精度光学测量技术,广泛应用于长度测量、速度/加速度测量、光学参数测量、气体浓度测量、空气颗粒度测量等领域,具有非接触测量、精度高、灵敏度高、量程较大等显著优势,同时也对仪器设备的环境适应性设计提出了更高的要求。在基于干涉放大的吸收光谱腔的设计过程中,为避免由于温度、自振等干扰给系统带来的固有误差,在结构设计中采用应力屏蔽或吸收的形式能够很好的降低外界振动激励,而对于温度的响应就显得尤为重要。文章设计了一款用于激光干涉放大吸收光谱仪器中应用的低温度响应保温舱体,采用多层保温材料结合可控换热窗口的设计,在内部发热功率一定的情况下,通过解传导、对流换热线性方程组确立了舱体内外温差与内部对流换热系数之间的关系,为各层保温材料的换热系数选取与厚度设计提供了可靠依据。在外界为室温常态的对流状态时(对流换热系数约为3.0W/m^2/K),50W的内部发热情况下,能够实现内外75℃左右的温差,并通过有限元软件验证计算;且由于隔热设计,系统对高频正弦谐波输入的温度具有降低响应速度和幅度的良好效果,得到了较大的阻尼系数。该设计能够为干涉测量仪器提供良好的运行环境,降低系统固有的温度干扰,实现长期稳定的精密测量。

Laser interference detective is a kind of high precision optical measurement technology.Due to the significant advantages of non-contact,high precision,high sensitivity and wide measure range,it has been extensively applied to length measurement,velocity/acceleration measurement,optic parameters detective,trace gas detective,particle ratio within air detective,etc.The interferential cavity amplified optic spectral measurement tech is one of the most important application in laser interference detective.It employs ultra-highly precision in measuring the spectrum corresponding to the stability of geometric dimensions of the cavity.Along with such micro-and nano-measurement scale,preference for mechanical stability against the variable environment is extremely desired.In general,temperature disturbance and mechanical vibration respond for systematical error,and vibration shielding/absorbing is always adapted in the structure.While,the temperature isolation and response are more dominating.An insensitive temperature response chamber for laser interferential signal amplified spectral measurement device is presented in this article.The mainly temperature management strategy is the combination of multi-layer of isolations and actively manipulated heat transfer port.Simultaneously solving the equations of heat conduction and heat convection,either the temperature difference between the internal and external,or the appropriate internal convective coefficient is definitely determined.When internal heat generation rate is 50 W,it achieves an 75℃ difference while the external convection is generally stable(3.0 W/m^2/K).The finite element analysis(FEA)agrees well.Based on these implements,it tends to reduce the response period and magnitude of the temperature variation in internal significantly when accompanying a high frequency sinusoidal harmonic temperature input in this system.A high temperature resistance is achieved within the system.We believe that the presented configuration can provide a stable environment,reduce the intrinsic temperature disturbance and maintain the long-period precision.