An aircraft-based Ion Trap Mass Spectrometer Instrument ITCIMS for measurements of atmospheric trace gases and ions aboard HALO - Phase 2: Extensions of ITCIMS capabilities, flight tests on the FALCON, and deployment on HALO

HALO-ITCIMS项目的第二阶段旨在扩展能力，并在研究飞机HALO上部署一种新型的、高度通用的基于飞机的离子阱质谱仪（离子阱化学电离质谱仪）。ITCIMS能够对大气痕量气体（包括超痕量气体和气相离子）进行快速和非常敏感的原位测量。ITCIMS仪器可以在多种模式下工作，包括主动和被动CIMS（化学电离质谱），用于使用负离子和正离子试剂检测痕量物质。主动CIMS模式涉及板载离子源产生的试剂离子。被动cims模式（PACIMS）涉及环境大气离子作为试剂离子，并且非常敏感（最小可检测的大气痕量气体摩尔分数：约0.0001 pptv）。此外，ITCIMS可以在离子碎裂模式下运行，这允许对质量选择的离子进行碰撞碎裂研究。这种模式对离子的识别非常有帮助，从而也有助于CIMS检测到的中性物质。ITMS的主要优点是其出色的占空比和能够同时和非常快速地测量非常大的质谱范围（20- 4000原子质量单位）。对于计划的主动cims测量，ITCIMS仪器将最好在负试剂离子模式下操作，而计划的PACIMS测量将涉及环境负离子和正离子作为试剂离子。HALO上的ITCIMS的微量气体测量重点将放在对大气光化学和气溶胶形成具有重要作用的物种上。要测量的重要气体包括：PAN、PPN、M-PAN、N2O5、HNO3、HCN、HCl、SO2、ClNO2、Br2、BrO、有机酸、H2SO4、NH3、（CH3）2CO和其他有机物。HALO-ITCIMS项目第二阶段包括5个主要部分：(1) ITCIMS能力的扩展，重点是中性痕量气体检测的新型离子-分子反应方案，以及大气气相离子测量的改进。(2)ITCIMS和新型离子反应方案的实验室测试，也将通过DLRIPA最近建立的新型非常强大的实验室质谱仪（双曲棒三重四极杆质谱仪，提供非常高的质量分辨率和质量精度）。TQMS还提供了一种替代的质量选择离子碎片模式)(3)在“猎鹰”号研究飞机和“光晕”号研究飞机上对ITCIMS进行测试(4)为在“光晕”号上部署第二台ITCIMS仪器进行改装(5)在使用“光晕”号的大型科学测量活动框架内部署ITCIMS仪器。

The second phase of project HALO-ITCIMS aims for an extension of the capabilities and the deployment aboard the research aircraft HALO of a novel and highly versatile aircraft-based ion trap mass spectrometer-instrument ITCIMS (Ion Trap Chemical Ionization Mass Spectrometer). The ITCIMS has the capability to make fast and very sensitive in-situ measurements of atmospheric trace gases, including also ultra-trace gases, and gas-phase ions. The ITCIMS instrument can be operated in various modes including active and passive CIMS (chemical ionization mass spectrometry) for trace substance detection using negative and positive reagent ions. The active CIMS mode involves reagent ions generated by an onboard ion source. The passive CIMS-mode (PACIMS) involves ambient atmospheric ions as reagent ions and is extremely sensitive (smallest detectable atmospheric trace gas mole fraction: about 0.0001 pptv). In addition, the ITCIMS can be operated in an ion fragmentation mode, which allows collisional fragmentation studies of mass selected ions. This mode is extremely helpful for the identification of ions and thereby also of neutral species to be detected by CIMS. Major advantages of the ITMS are its excellent duty cycle and its ability to offer simultaneous and very fast measurements of a very large mass spectral range (20- 4000 atomic mass units). For the planned active CIMS-measurements the ITCIMS instrument will be operated preferably in the negative reagent ion mode while planned PACIMS measurements will involve ambient negative and positive ions as reagent ions. The focus of the trace gas measurements by ITCIMS aboard HALO will be on species having major roles in atmospheric photochemistry and aerosol formation. Important gases to be measured include among others: PAN, PPN, M-PAN, N2O5, HNO3, HCN, HCl, SO2, ClNO2, Br2, BrO, organic acids, H2SO4, NH3, (CH3)2CO, and additional organics. Phase 2 of the HALO-ITCIMS project has 5 major parts: (1) Extensions of the ITCIMS capabilities focussing on novel ion-molecule reaction schemes for neutral trace gas detection and focussing also on improvements of atmospheric gas-phase ion measurements (2) Tests of ITCIMS and novel ion reaction schemes in the laboratory, which will be also by a novel very powerful laboratory mass spectrometer recently set up at DLRIPA (triple quadrupole mass spectrometer with hyperbolic rods offering a very high mass resolution and mass precision. The TQMS also offers an alternative mass selected ion fragmentation mode) (3) Tests of ITCIMS on the research aircraft FALCON and on the research aircraft HALO (4) Conversion of a second ITCIMS instrument for the deployment aboard HALO (5) Deployment of the ITCIMS instrument within the framework of large scientific measurement campaigns using HALO.