Aikin A C, Maier E J
Laboratory for Planetary Atmospheres, Goddard Space Flight Center, Greenbelt, Maryland 20771.
Rev Sci Instrum. 1978 Aug;49(8):1034. doi: 10.1063/1.1135518.
A balloon-borne photoionization mass spectrometer used to measure stratospheric trace gases is described. Ions are created with photons from high-intensity krypton discharge lamps and a quadrupole mass analyzer is employed for ion identification. Differential pumping is achieved with liquid helium cryopumping. To insure measurement of unperturbed stratospheric air, the entire system is contained in a sealed gondola and the atmospheric sample is taken some distance away during descent. The photoionization technique allows the detection of a low ionization potential constituent, such as nitric oxide, at less than a part in 10(9) in the presence of the major atmospheric gases and their isotopes. Operation of the mass spectrometer system was demonstrated during a daytime flight from Palestine, Texas on 26 April 1977. The sensitivity achieved and the unique selectivity afforded by this technique offer a capability for trace constituent measurement not possible with the more conventional electron impact ionization approach.
本文描述了一种用于测量平流层痕量气体的气球携带式光致电离质谱仪。离子由高强度氪放电灯产生的光子形成，采用四极质量分析仪进行离子识别。通过液氦低温泵实现差动抽气。为确保测量未受扰动的平流层空气，整个系统置于密封吊舱内，在下降过程中于一定距离处采集大气样本。光致电离技术能够在主要大气气体及其同位素存在的情况下，检测出低电离势成分，如一氧化氮，检测限低于十亿分之一。1977年4月26日，该质谱仪系统在从得克萨斯州巴勒斯坦进行的一次白天飞行中进行了演示。该技术所达到的灵敏度和独特的选择性为痕量成分测量提供了一种采用更传统的电子碰撞电离方法无法实现的能力。
