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大能力，并在研究飞机Halo上部署一种新型和高度通用的机载离子陷阱质谱仪-仪器ITCIMS(离子陷阱化学电离质谱仪)。ITCIMS有能力对大气痕量气体进行快速、非常灵敏的现场测量，包括超微量气体和气相离子。ITCIMS仪器可在多种模式下工作，包括主动和被动CIMS(化学电离质谱仪)，使用阴离子和阳离子进行痕量物质检测。主动CIMS模式包括由机载离子源产生的试剂离子。被动式电感耦合等离子体质谱(PACIMS)以环境大气离子为试剂离子，具有极高的灵敏度(最小可检测到的大气痕量气体摩尔分数约为0.0001 PPTV)。此外，ITCIMS可以在离子碎裂模式下运行，这允许对大量选定的离子进行碰撞碎裂研究。这种模式对离子的鉴定非常有帮助，因此对电离质谱仪要检测的中性物种也是非常有帮助的。ITMS的主要优势在于其出色的占空比，并且能够提供对非常大的质量光谱范围(20-4000原子质量单位)的同时和非常快速的测量。对于计划中的主动CIMS测量，ITCIMS仪器将优先在负试剂离子模式下运行，而计划中的PACIMS测量将使用环境中的负离子和阳离子作为试剂离子。光环上ITCIMS的痕量气体测量的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。需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项目第二阶段包括五个主要部分：(1)扩展ITCIMS的能力，侧重于中性痕量气体探测的新型离子-分子反应机制，并侧重于改进大气中痕量离子的测量；(2)ITCIMS测试和实验室中的新型离子反应计划，这也将是最近在DLRIPA(具有双曲线棒的三重四极杆质谱仪)安装的一台新型的非常强大的实验室质谱仪，提供非常高的质量分辨率和质量精度。TQMS还提供了另一种质量选择离子破碎模式)(3)在猎鹰研究飞机和HALO研究飞机上进行ITCIMS测试(4)改装第二台ITCIMS仪器，以便在HALO上部署(5)在使用HALO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.