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Title: Quantitative detection of tiny amounts of helium isotopes in a hydrogen isotope atmosphere using a standard-resolution quadrupole mass spectrometer

Abstract

This article describes a new method to quantitatively detect extremely small amounts of helium (and eventually other inert gases) in complex gaseous mixtures, even in the presence of very high concentrations of hydrogen isotopes, despite using a conventional (i.e., standard-resolution) quadrupole mass spectrometer. This is accomplished by means of two nonevaporable getter (NEG) pumps, which effectively remove all active components in the original gas mixture with particular regard to hydrogen isotopes. Obviously, noble gases are preserved. The gas sample to be analyzed is initially admitted in a first chamber equipped with a NEG pump operating at high temperature ({approx_equal}450 deg. C), in order to remove most of the active gases quickly. The residual gas mixture is then allowed to expand through a gate valve into the analysis chamber, where a second NEG pump, operating at room temperature, completes the selective pumping action and removes to high degree hydrogen isotopes and other chemically active gases. The turbomolecular pump, which is used to evacuate the chamber, is excluded during the analysis. The results of extensive tests carried out with a fully automated facility built at ENEA Frascati are reported, demonstrating the effectiveness of this method which allows detection of {sup 4}He/D{sub 2}more » peak ratios as small as {approx_equal}2.5x10{sup -7}. During these tests, a quadrupole mass spectrometer which can operate in both standard- and high-resolution modes has been used. This latter operating mode has been selected, when necessary, in order to provide evidence for the absence of deuterium contributions to mass 4.« less

Authors:
; ;  [1]
  1. ENEA-Unita Tecnico Scientifica Fusione-Centro Ricerche Frascati, Via E. Fermi, 45 Frascati (Rome) (Italy)
Publication Date:
OSTI Identifier:
20853952
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films; Journal Volume: 25; Journal Issue: 1; Other Information: DOI: 10.1116/1.2395948; (c) 2007 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DETECTION; DEUTERIUM; HELIUM; HELIUM 4; MASS SPECTROMETERS; MIXTURES; PUMPS; QUADRUPOLES; RESOLUTION; TEMPERATURE RANGE 0273-0400 K; TEMPERATURE RANGE 0400-1000 K

Citation Formats

Frattolillo, A., De Ninno, A., and Rizzo, A. Quantitative detection of tiny amounts of helium isotopes in a hydrogen isotope atmosphere using a standard-resolution quadrupole mass spectrometer. United States: N. p., 2007. Web. doi:10.1116/1.2395948.
Frattolillo, A., De Ninno, A., & Rizzo, A. Quantitative detection of tiny amounts of helium isotopes in a hydrogen isotope atmosphere using a standard-resolution quadrupole mass spectrometer. United States. doi:10.1116/1.2395948.
Frattolillo, A., De Ninno, A., and Rizzo, A. Mon . "Quantitative detection of tiny amounts of helium isotopes in a hydrogen isotope atmosphere using a standard-resolution quadrupole mass spectrometer". United States. doi:10.1116/1.2395948.
@article{osti_20853952,
title = {Quantitative detection of tiny amounts of helium isotopes in a hydrogen isotope atmosphere using a standard-resolution quadrupole mass spectrometer},
author = {Frattolillo, A. and De Ninno, A. and Rizzo, A.},
abstractNote = {This article describes a new method to quantitatively detect extremely small amounts of helium (and eventually other inert gases) in complex gaseous mixtures, even in the presence of very high concentrations of hydrogen isotopes, despite using a conventional (i.e., standard-resolution) quadrupole mass spectrometer. This is accomplished by means of two nonevaporable getter (NEG) pumps, which effectively remove all active components in the original gas mixture with particular regard to hydrogen isotopes. Obviously, noble gases are preserved. The gas sample to be analyzed is initially admitted in a first chamber equipped with a NEG pump operating at high temperature ({approx_equal}450 deg. C), in order to remove most of the active gases quickly. The residual gas mixture is then allowed to expand through a gate valve into the analysis chamber, where a second NEG pump, operating at room temperature, completes the selective pumping action and removes to high degree hydrogen isotopes and other chemically active gases. The turbomolecular pump, which is used to evacuate the chamber, is excluded during the analysis. The results of extensive tests carried out with a fully automated facility built at ENEA Frascati are reported, demonstrating the effectiveness of this method which allows detection of {sup 4}He/D{sub 2} peak ratios as small as {approx_equal}2.5x10{sup -7}. During these tests, a quadrupole mass spectrometer which can operate in both standard- and high-resolution modes has been used. This latter operating mode has been selected, when necessary, in order to provide evidence for the absence of deuterium contributions to mass 4.},
doi = {10.1116/1.2395948},
journal = {Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films},
number = 1,
volume = 25,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • Deuterium pressure in deuterium-helium mixture gas is successfully measured by a common quadrupole mass spectrometer (model: RGA200) with a resolution of ∼0.5 atomic mass unit (AMU), by using varied ionization energy together with new developed software and dedicated calibration for RGA200. The new software is developed by using MATLAB with the new functions: electron energy (EE) scanning, deuterium partial pressure measurement, and automatic data saving. RGA200 with new software is calibrated in pure deuterium and pure helium 1.0 × 10{sup −6}–5.0 × 10{sup −2} Pa, and the relation between pressure and ion current of AMU4 under EE = 25 eVmore » and EE = 70 eV is obtained. From the calibration result and RGA200 scanning with varied ionization energy in deuterium and helium mixture gas, both deuterium partial pressures (P{sub D{sub 2}}) and helium partial pressure (P{sub He}) could be obtained. The result shows that deuterium partial pressure could be measured if P{sub D{sub 2}} > 10{sup −6} Pa (limited by ultimate pressure of calibration vessel), and helium pressure could be measured only if P{sub He}/P{sub D{sub 2}} > 0.45, and the measurement error is evaluated as 15%. This method is successfully employed in EAST 2015 summer campaign to monitor deuterium outgassing/desorption during helium discharge cleaning.« less
  • To apply mass spectrometers and ionization gauges to thermonuclear fusion devices such as pressure gauges, we measured the relative sensitivities (normalized to H/sub 2/) of Bayard--Alpert (B--A) gauges (UGD-1S and UGS-1A, ANELVA Co.) and a quadrupole mass spectrometer (MSQ-150A, ULVAC Co.) for hydrogen isotopes. In the case of the B--A gauges, the relative sensitivities were determined as R/sup HD//sub B/ = 1.07, R/sup =//sub B/ = 0.99, R/sup HT//sub B/ = 1.03, R/sup DT//sub B/ = 0.97, and R/sup =//sub B/ = 0.95. In the case of the quadrupole mass spectrometer, they were R/sup HD//sub M/ = 1.09, R/sup =//submore » M/ = 0.99, R/sup HT//sub M/ = 1.06, R/sup DT//sub M/ = 0.96, and R/sup =//sub M/ = 0.88. These values agreed quite well with those observed by Dibeler et al. for the mass spectrometer of the magnetic deflection type. It was revealed that the relative sensitivities of the quadrupole mass spectrometer were essentially the same as those for the B--A gauges except T/sub 2/.« less
  • The technique of Resonance Ionization Spectroscopy (RIS) is being extended to develop a means for counting individual atoms of a selected isotope of a noble gas. In this method, lasers are used for RIS to obtain atomic species (Z) selectivity and a small quadrupole mass spectrometer provides isotopic (A) selectivity. A progress report on the objective of counting each atom of a particular isotope of a noble gas is given. 11 references, 4 figures.