Some theoretical considerations of ion optics of the mass spectrometer ion source: II. Evaluation of ion beam transmission efficiency

Abstract. Knowledge about mass discrimination effects in a chemical ionization mass spectrometer (CIMS) is crucial for quantifying, e.g., the recently discovered extremely low volatile organic compounds (ELVOCs) and other compounds for which no calibration standard exists so far. Here, we present a simple way of estimating mass discrimination effects of a nitrate-based chemical ionization atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer. Characterization of the mass discrimination is achieved by adding different perfluorinated acids to the mass spectrometer in amounts sufficient to deplete the primary ions significantly. The relative transmission efficiency can then be determined by comparing the decrease of signals from the primary ions and the increase of signals from the perfluorinated acids at higher masses. This method is in use already for PTR-MS; however, its application to a CI-APi-TOF brings additional difficulties, namely clustering and fragmentation of the measured compounds, which can be treated with statistical analysis of the measured data, leading to self-consistent results. We also compare this method to a transmission estimation obtained with a setup using an electrospray ion source, a high-resolution differential mobility analyzer and an electrometer, which estimates the transmission of the instrument without the CI source. Both methods give different transmission curves, indicating non-negligible mass discrimination effects of the CI source. The absolute transmission of the instrument without the CI source was estimated with the HR-DMA method to plateau between the m∕z range of 127 and 568 Th at around 1.5 %; however, for the CI source included, the depletion method showed a steady increase in relative transmission efficiency from the m∕z range of the primary ion (mainly at 62 Th) to around 550 Th by a factor of around 5. The main advantages of the depletion method are that the instrument is used in the same operation mode as during standard measurements and no knowledge of the absolute amount of the measured substance is necessary, which results in a simple setup.

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Effect of preacceleration on intense ion‐beam transmission efficiency

Applied Physics Letters ◽

10.1063/1.90364 ◽

1978 ◽

Vol 33 (4) ◽

pp. 278-279 ◽

Cited By ~ 18

Author(s):

J. H. Whealton ◽

C. C. Tsai ◽

W. K. Dagenhart ◽

W. L. Gardner ◽

H. H. Haselton ◽

...

Keyword(s):

Ion Beam ◽

Transmission Efficiency ◽

Beam Transmission

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The Gas Field Ion Source for Finely Focused Ion Beam Systems

MRS Proceedings ◽

10.1557/proc-396-687 ◽

1995 ◽

Vol 396 ◽

Author(s):

W. Thompson ◽

A. Armstrong ◽

S. Etchin ◽

R. Percival ◽

A. Saxonis

Keyword(s):

Metal Ion ◽

Focused Ion Beam ◽

Vacuum Chamber ◽

Ion Beam ◽

Beam Current ◽

Ion Source ◽

Max Planck ◽

Gas Field ◽

Ion Optics ◽

Ion Species

AbstractThe Gas Field Ion Source, GFIS, promises a 109A/(cm2 str) brightness, small beam sizes, and inert gas ion species. If this performance could be demonstrated on a commercial system, the GFIS might replace the liquid metal ion source as the standard source for FIB applications. Recent work at the Max-Planck-Institut für Kernphysik (MPI-K) in Heidelberg, Germany has shown that a GFIS with a ‘Super Tipped’ emitter can be reliably fabricated and can be run with stable helium beam current for more than 200 hours. However, this GFIS source must operate in a bakable UHV chamber, at cryogenic temperatures, and at high voltages with low vibration. A GFIS is now being integrated with high resolution ion optics and a vacuum chamber designed for studying GFIS image quality and ion induced chemistry.

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Characterization of the mass dependent transmission efficiency of a CIMS

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-8-11369-2015 ◽

2015 ◽

Vol 8 (11) ◽

pp. 11369-11399 ◽

Cited By ~ 2

Author(s):

M. Heinritzi ◽

M. Simon ◽

G. Steiner ◽

A. C. Wagner ◽

A. Kürten ◽

...

Keyword(s):

Mass Spectrometer ◽

Chemical Ionization ◽

Transmission Efficiency ◽

Ion Source ◽

Mass Discrimination ◽

Perfluorinated Acids ◽

Relative Transmission ◽

The Absolute ◽

Primary Ions

Abstract. Knowledge about mass discrimination effects in a Chemical Ionization Mass Spectrometer (CIMS) is crucial for quantifying e.g. the recently discovered Extremely Low Volatile Organic Compounds (ELVOCs) and other compounds for which no calibration standard exists so far. Here, we present a simple way of estimating mass discrimination effects of a nitrate based Chemical Ionization Atmospheric Pressure interface Time of Flight (CI-APi-TOF) mass spectrometer. Characterization of the mass discrimination is achieved by adding different perfluorinated acids to the mass spectrometer in amounts sufficient to deplete the primary ions significantly. The relative transmission efficiency can then be determined by comparing the decrease of signals from the primary ions and the increase of signals from the perfluorinated acids at higher masses. This method is in use already for PTR-MS, however its application to a CI-APi-TOF brings additional difficulties, namely clustering and fragmentation of the measured compounds, which can be treated with statistical analysis of the measured data, leading to self-consistent results. We also compare this method to a transmission estimation obtained with a setup using an Electrospray Ion source, a High Resolution Differential Mobility Analyzer and an electrometer, which estimates the transmission of the instrument without the CI source. Both methods give different transmission curves, indicating non-negligible mass discrimination effects of the CI source. The absolute transmission of the instrument without the CI source was estimated with the HR-DMA method to plateau between the m / z range of 127 and 568 Th at around 1.5 %, however for the CI source included, the depletion method showed a steady increase in relative transmission efficiency from the m / z range of the primary ion (mainly at 62 Th) to around 550 Th by a factor of around 5. The main advantages of the depletion method are that the instrument is used in the same operation mode as during standard measurements and no knowledge of the absolute amount of the measured substance is necessary, which results in a simple setup.

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Nucleation and Early Growth of Sputtered thin Films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069570 ◽

1970 ◽

Vol 28 ◽

pp. 516-517

Author(s):

Dudley M. Sherman ◽

Thos. E. Hutchinson

Keyword(s):

Thin Films ◽

Electron Beam ◽

Ion Beam ◽

Ion Source ◽

Water Cooling ◽

Stages Of Growth ◽

Lens Assembly ◽

Microscope Technique ◽

Ion Beam Sputter Deposition

The in situ electron microscope technique has been shown to be a powerful method for investigating the nucleation and growth of thin films formed by vacuum vapor deposition. The nucleation and early stages of growth of metal deposits formed by ion beam sputter-deposition are now being studied by the in situ technique.A duoplasmatron ion source and lens assembly has been attached to one side of the universal chamber of an RCA EMU-4 microscope and a sputtering target inserted into the chamber from the opposite side. The material to be deposited, in disc form, is bonded to the end of an electrically isolated copper rod that has provisions for target water cooling. The ion beam is normal to the microscope electron beam and the target is placed adjacent to the electron beam above the specimen hot stage, as shown in Figure 1.

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Features of tests of miniature gas-filled spark gaps on tightness in the conditions of unstable work ion source of mass spectrometer

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2018-4-62-69 ◽

2018 ◽

pp. 62-69

Author(s):

S. A. Bushin

Keyword(s):

Mass Spectrometer ◽

Ion Source

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Optimizing Gas-Assisted Processes for Ga and Xe FIB Circuit Edit Application

ISTFA 2016: Conference Proceedings from the 42nd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2016p0397 ◽

2016 ◽

Author(s):

Valery Ray ◽

Josef V. Oboňa ◽

Sharang Sharang ◽

Lolita Rotkina ◽

Eddie Chang ◽

...

Keyword(s):

Inductively Coupled Plasma ◽

Structural Damage ◽

Focused Ion Beam ◽

Ion Beam ◽

Beam Width ◽

Ion Source ◽

Reconstruction Technique ◽

Beam Diameter ◽

Current Profile ◽

Single Beam

Abstract Despite commercial availability of a number of gas-enhanced chemical etches for faster removal of the material, there is still lack of understanding about how to take into account ion implantation and the structural damage by the primary ion beam during focused ion beam gas-assisted etching (FIB GAE). This paper describes the attempt to apply simplified beam reconstruction technique to characterize FIB GAE within single beam width and to evaluate the parameters critical for editing features with the dimensions close to the effective ion beam diameter. The approach is based on reverse-simulation methodology of ion beam current profile reconstruction. Enhancement of silicon dioxide etching with xenon difluoride precursor in xenon FIB with inductively coupled plasma ion source appears to be high and relatively uniform over the cross-section of the xenon beam, making xenon FIB potentially suitable platform for selective removal of materials in circuit edit application.

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