Electrode structure of a compact microwave driven capacitively coupled atomic beam source

Abstract

A compact magnetic field free atomic beam source was designed, assembled and tested the performance to produce hydrogen and nitrogen atoms. A forced air-cooled solid-state microwave power supply at 2.45 GHz frequency drives the source up to 100 W through a coaxial transmission cable coupled to a triple stub tuner for realizing a proper matching condition to the discharge load. The discharge structure of the source affected the range of operation pressure, and the pressure was reduced by four orders of magnitude through improving the electrode geometry to enhance the local electric field intensity. Optical emission spectra of the produced plasmas indicate production of hydrogen and nitrogen atoms, while the flux intensity of excited nitrogen atoms monitored by a surface ionization type detector showed the signal level close to a source developed for molecular beam epitaxy applications with 500 W RF power.

Structural Analysis of Phospholipid Using Hydrogen Abstraction Dissociation and Oxygen Attachment Dissociation in Tandem Mass Spectrometry

“…OH • and 3 O were generated by an in-house built radical source based on a microwave-driven capacitively coupled plasma generator, as shown in Figure S1 . A 2.45-GHz microwave was applied to the quarter-inch (6.35 mm) outer diameter copper tube via an N-type radio frequency (RF) connector and a coaxial cable from a solid-state type microwave power generator (Tokyo Keiki Inc., TMEB101B00B).…”

Tandem Mass Spectrometry of Peptide Ions by Microwave Excited Hydrogen and Water Plasmas

“…Optical fibers fixed at the center of the view port facing the ECR-ICP source orifice deliver optical signals to the two optical multichannel analyzers to investigate the OES in both visible light region (Ocean optics USB 2000+), and ultraviolet region (Ocean optics Flame-S), respectively. Figure 2 shows the typical OES from the ECR-ICP and CCP 9 for hydrogen. Since the signal depends on the size of the aperture, gas pressure, and matching condition, the ordinates do not coincide among different spectra.…”

“…Following Demirev's experiment of H radical (H • ) production in Fourier transform ion cyclotron resonance (FT-ICR), 10 relative H radical density inside the ion trap was estimated by observing H radical attachment to fullerene ions. Figure 3 show the isotopic distribution of C 60 +• observed at 1.0 s of reaction time using (A) ICP discharge, (B) CCP discharge, 9 and (C) thermal cracking used in our previous work of HAD 5 operated with pure H 2 gas. The flow rates of input H 2 gas are set to 4 sccm in thermal cracking source and 100 sccm in microwave plasma source.…”

“…Our previous work indicated that the electrode geometry to enhance the local electric field was an important factor to reduce the operation gas pressure and increase the degree of dissociation with 2.45 GHz microwave driven CCP atomic sources. 9 Further study on atomic source using 2.45 GHz microwave plasma excitation is being made, and we report the HAD performance of an electrodeless discharge system, which we call ECR-ICP (electron cyclotron resonance-inductively coupled plasma) source. An optical emission spectroscopy confirmed the presence of radical species in the discharge plasma for both CCP and ECR-ICP configuration.…”

Identifying Double Bond Positions in Phospholipids Using Liquid Chromatography-Triple Quadrupole Tandem Mass Spectrometry Based on Oxygen Attachment Dissociation

“…7) As reported by Shimabukuro and co-workers, the microwave-driven ICP source generates a higher radical ux than the microwave-driven CCP source at a high vacuum (< 0.1 Pa). 10,11) Since the gas pressure of the collision cell is equivalent to the operating pressure of the microwave-driven ICP (≈ 0.1 Pa), the latter can be directly connected to the collision cell without the need for di erential pumping.…”