Constraction and Development of laser-furnace TOF-Mass Spectrometer

对swnt中间体及其前体的研究对于理解swnt的生长机制特别有趣。本文研制了一种新型含碳材料烟尘的制备和分析装置，该装置由激光炉和LD TOF质谱联用组成。该仪器被称为高温激光汽化- LD TOF质谱仪。它由一个在石英管（内径28毫米）中有靶棒的电炉、一个烟灰沉积的样品板（15×15毫米）转移室和一个线性反射TOF质谱仪组成。Ni(0.6 at.%)/Co（0.6 at.%）%)或Ni (4.2 at.%)/Y（1.0 at.%）。%)掺杂石墨复合棒(Toyo Tanso Co.Ltd。（5×5×20 mm）作为靶棒。利用Nd: YAG激光器（532 nm, 10Hz, 6-7ns， 600 mJ/脉冲，直径约0.1 mm光斑；Spectra-Physics GCR-250）的二次谐波输出，在温度范围为30 ~ 1000℃的氩气流（760 Torr, 300 ml/min）条件下蒸发金属掺杂的图形复合棒。采取了特别的预防措施使目标棒的新鲜表面汽化。在水冷镍板上收集了含有各种新碳种的煤烟以及富勒烯和单壁碳纳米管。该板被厌氧转移到LD TOF质谱仪的加速区，使我们能够进行原位TOF质量分析。质谱分析在LD TOF-MS室进行。线性反射型LD TOF质谱仪采用垂直激光解吸。另一个Nd: YAG激光器（355nm 2Hz, HOYA Continuum MINILIGHT II）的三次谐波输出解吸并电离板上的烟尘产物。利用这种新装置，我们首次可以生产、分离和表征较小的富勒烯，如C36种。我们还发现C36的形成与单壁碳纳米管的形成密切相关。

Investigations of SWNT-intermediates and its precursors are particularly interesting in understanding the growing mechanism of SWNTs. We have developed a new apparatus to produce and analyze soot containing new carbon materials, which consists of a laser-furnace combined anaerobically with a LD TOF mass spectrometer.The apparatus is called as the high-temperature laser vaporization- LD TOF mass spectrometer. It consists of an electric furnace with a target rod in a quartz tube (28 mm inner diameter), a transferring chamber of a sample plate (15×15 mm) on which soot deposits, and a linear reflectron TOF mass spectrometer. Ni(0.6 at.%)/Co(0.6 at.%) or Ni (4.2 at.%)/Y(1.0 at.%) doped graphite composite rods (Toyo Tanso Co.Ltd., 5×5×20 mm) were used for target rods.The second-harmonic output of a Nd : YAG laser (532 nm, 10Hz, 6-7ns, 600 mJ/pulse, ca.1mm diam.spot ; Spectra-Physics GCR-250) was used to vaporize the metal-doped graphic composite rod at a temperature range of 30 -1,000 deg C in an Ar flow (760 Torr, 300 ml/min.) condition. Special precaution was taken to vaporize the fresh surface of the target rod.The soot containing various new carbon species together with fullerenes and SWNTs were collected on a water cooled nickel plate. The plate was anaerobically transferred to the acceleration region of the LD TOF mass spectrometer, which enable us to perform in situ TOF mass analyses. The mass analysis was done in the LD TOF-MS chamber.The linear reflectron-type LD TOF mass spectrometer employs vertical laser desorption. The third-harmonic output of the other Nd : YAG laser (355nm 2Hz, HOYA Continuum MINILIGHT II) desorbes and ionizes the soot product on the plate.With this new apparatus we can produce, separate/isolate and characterize smaller fullerenes such as C36 species for the first time. We also found that the formation of C36 species is closely related that of single-wall carbon nanotubes.