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The two plasma gases operate by different mechanisms. We have demonstrated the enhancement in mass spectrometric signal obtained when using hydrogen-doped argon as the support gas in an ADI source compared with the signal obtained with the pure gas discharge. There is a wide variety of gas mixtures that could be tested to enhance the ionization efficiency when using plasma gases such as helium, argon, and nitrogen.
More research is needed in this field to exploit the many potential advantages. Experiments with downstream grounds emphasize the complex nature of the interaction of the discharges, particularly the DBDs, with their surroundings. Their performance depends strongly on the environment in which they are operated. The operating conditions of the mass spectrometer as well as interactions with conducting surfaces present while operating ADI plasma sources have significant effects on the signal enhancement with added H 2.
Takats, Z. Science , — Cody, R. Harper, J. Andrade, F. Desorption-ionization for the direct analysis of solid compounds. Na, N. Mass Spectrom.
Venter, A. Article Google Scholar. Monge, M. Chan, G. Wright, J. Heywood, M. Albritton, D. Data Nucl. Data 22 , 1—89 Bedford, D. Eiden, G. Selective removal of plasma matrix ions in plasma source mass spectrometry. Koppenaal, D. Rothwell, H. McKay, K.
Plasma Sources Sci. Hunter, E. Data 27 , — Sung Lee, H. Hayen, H. Wiley, J. Analyst , — Reininger, C. Acta B , 98— Hanley, D. Jackson, A. Shelley, J. Bogaerts, A. Acta B 57 , — Herman, J. Laidani, N. D Appl. Download references. Wade C. Ellis, Charlotte R. Lewis, Anna P.
You can also search for this author in PubMed Google Scholar. Correspondence to Paul B. Reprints and Permissions. Ellis, W. Download citation. Received : 05 November Revised : 06 June Accepted : 11 June Published : 05 July Issue Date : September Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content.
Search SpringerLink Search. Download PDF. Experimental Chemicals The chemicals used in this study were chosen to match previous studies [ 9 , 10 , 20 , 21 ] done with pure helium and hydrogen-doped helium. Figure 1. Full size image. Results and Discussion Optimal Amount of Hydrogen in Argon By performing experiments with differing ratios of hydrogen in argon, we were able to ascertain the best point at which to perform other analyses.
Figure 2. Figure 3. Figure 4. The gases he uses are helium, neon, argon, krypton, and xenon. These same gases are used in neon signs because they are so easy to turn into plasma.
However, they are very hard to ionize which brings us to the following question: why indeed are all these gases so easy to turn into a plasma when they are so difficult to ionize? Watch the video to find out the answer.
By subscribing, you agree to our Terms of Use and Privacy Policy. What this software basically does is computing the electron energy distribution function EEDF given the cross section data of the gas which is experimentally obtained data. For the same Electric field to gas density ratio, the mean energy of an electron in He gas is much larger than what it is in O2.
I did the following plot of mean electron energy as function of reduced electric field in both air and Helium. The reduced electric field is the electric field devided by number density.
Its unit is Townsend. So for example at Td, mean electron energy of an electron in helium is higher than the first ionization energy of Helium, while in air it is lower than first ionization energy of either O2 or N2.
The reason the mean free path differs significantly is that N2 and O2 are more chemically active compared to He, which means the electrons have too many possible ways of spending their energy in rotational and vibration excitation, dissociation and excitation to metastable states while in He those ways are very limited.
Also it is true that the mass of a Helium atom is much smaller than the mass of O2 or N2 molecule, being the basic unit in the gas. So from a rough geometrical perspective, the He atoms are smaller in size than O2 or N2 molecules.
The geometrical size is not really relevant but it helps to explain the concept. So I think when they say it stabilizes the system, they also mean that it mediates the energy in the system, from the discharge input to the chemistry. Sign up to join this community. The best answers are voted up and rise to the top.
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