Formation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">H</mml:mi><mml:mn /><mml:mo>(</mml:mo><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>2</mml:mn><mml:mn /><mml:mo>)</mml:mo><mml:mn /></mml:math>atoms by the nearly resonant process<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mm

Pradel, Pierre; Roussel, F.; Schlachter, A. S.; Spiess, G.; Valance, Alexandre

doi:10.1103/physreva.10.797

Cited by 74 publications

(17 citation statements)

References 48 publications

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“…11 The optimum temperature of the liquid cesium for the production of metastable atoms in our case is 160°C. A 10 g charge of cesium lasts several months.…”

Section: Methodsmentioning

confidence: 75%

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Precision Lamb-shift polarimeter for polarized atomic and ion beams

Engels

Emmerich

Ley

et al. 2003

Review of Scientific Instruments

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The Lamb-shift polarimeter described here enables the polarization of a beam of hydrogen ͑deuterium͒ atoms, or of a slow proton ͑deuteron͒ beam, to be measured with an absolute precision better than 1% within a few seconds. The polarimeter measures the intensity ratios of Lyman-␣ transitions after Stark quenching of metastable hyperfine substates that were selected in a spin filter. For that purpose the hydrogen ͑deuterium͒ atoms are ionized in a Glavish-type ionizer. By charge exchange of the protons ͑deuterons͒ in cesium vapor, atoms in the metastable 2S state are produced. For a hydrogen beam of 3ϫ10 16 atoms/s, ϳ3ϫ10 6 photons/s are registered in a photomultiplier, i.e., the polarimeter efficiency is about 10 Ϫ10. The signal-to-background ratio in the Lyman-␣ spectrum is excellent, thus beam intensities of one to two orders of magnitude less would still be sufficient to carry out a precise measurement. The different components of the polarimeter affect the measured polarization in several ways. It was, therefore, crucial to determine precisely the associated correction factors in order to derive the nuclear polarization from the measured Lyman-␣ spectra.

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“…11 The optimum temperature of the liquid cesium for the production of metastable atoms in our case is 160°C. A 10 g charge of cesium lasts several months.…”

Section: Methodsmentioning

confidence: 75%

“…Beam intensities of less than 10 15 atoms/s or 10 11 protons/s are required. Therefore, polarization measurements of the gas in a storage cell target appear feasible with a small number of atoms effusing from the cell.…”

Section: Introductionmentioning

confidence: 99%

Precision Lamb-shift polarimeter for polarized atomic and ion beams

Engels

Emmerich

Ley

et al. 2003

Review of Scientific Instruments

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“…It is created either by collisions with H 2 residual gas along the beam path, or by resonant charge exchange in a cell containing cesium vapor [1], labelled B on the photo of figure 3. We work with a 500 eV ion beam, which corresponds to the maximum cross section of this charge exchange process [16]. The beam is directed into a measurement chamber, labelled C on the photo of figure 3.…”

Section: Description Of the Diagnosticmentioning

confidence: 99%

Lamb-shift and electric field measurements in plasmas

Doveil¹,

Chérigier-Kovacic²,

Ström³

2016

Plasma Phys. Control. Fusion

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The electric field is a quantity of particular relevance in plasma physics. Indeed, its fluctuations are responsible for different macroscopic phenomena such as anomalous transport in fusion plasmas. Answering a long-standing challenge, we offer a new method to locally and non-intrusively measure weak electric fields and their fluctuations in plasmas, by means of a beam of hydrogen ions or atoms. We present measurements of the electric field in vacuum and in a plasma where Debye shielding is measured. For the first time, we have used the Lamb-shift resonance to measure oscillating electric fields around 1 GHz and observed the strong enhancement of the Lyman-α signal. The measurement is both direct and non-intrusive. This method provides sensitivity (mV cm −1 ) and temporal resolution (ns) that are three orders higher compared to current diagnostics. It thus allows measuring fluctuations of the electric field at scales not previously reached experimentally.

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“…Some collision studies on excited particles at high energy (E > 1 keV) such as He (2 'S, 2 3S) and H (2 S) in collision with rares gases or molecules have been carried out to determine the electron capture, electron loss or collisional destruction crosssection of the excited species [6][7][8]; in these experiments only the fast product of the reaction was Table I). The initial state of the collision complex is embedded in a continuum and is subject to autoionization at small distances (Penning ionization).…”

Section: Introductionmentioning

confidence: 99%

Chemi-ionization reactions involving metastable helium atoms at high energy

Pradel

Laucagne

1983

J. Phys. France

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-Total chemi-ionization cross-sections have been measured over the 15 to 1 500 eV energy interval for collisions of He 2 1S and 2 3S metastable atoms with Ne, H2, N2, O2 and CO, using a slow ion measurement technique. With molecular targets these measurements have shown a strong energy dependence for the total ionization cross-section without dissociation. In the case of dissociative ionization an energy threshold appears, dependent on the energy defect of the reaction.

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Formation ofH(n=2)atoms by the nearly resonant processH+

Cited by 74 publications

References 48 publications

Precision Lamb-shift polarimeter for polarized atomic and ion beams

Precision Lamb-shift polarimeter for polarized atomic and ion beams

Lamb-shift and electric field measurements in plasmas

Chemi-ionization reactions involving metastable helium atoms at high energy

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