Detection of atomic oxygen by laser-induced fluorescence spectroscopy at 130 nm

Döbele, H. F.; Hörl, M.; Röwekamp, M.; Reimann, B.

doi:10.1007/bf00694803

Cited by 17 publications

(3 citation statements)

References 14 publications

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“…Other species of interest, however, such as atomic hydrogen, oxygen, nitrogen, and also rare gas atoms like neutral xenon or krypton would require laser wavelengths in the VUV. In order to circumvent such short excitation wavelengths, which would result in significantly more complex set-ups including Raman-shifted lasers [14,15], simultaneous absorption of two photons can be applied. Examples of TALIF spectroscopy for plasma diagnostics are the determination of particle densities of low-Z atoms in plasma flows or jets [16][17][18][19][20][21][22], whereas measurements in rare gases, such as on neutral xenon or krypton, have been reported significantly less frequently, with concentration on the investigation of the neutral density depletion in helicon plasmas [23][24][25] or on a microwave cathode [26].…”

Section: Introductionmentioning

confidence: 99%

Single- and two-photon absorption laser-induced fluorescence spectroscopy in rare gases for gridded ion thruster diagnostics

et al. 2022

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Methods based on laser-induced fluorescence spectroscopy are widely used for spatially resolved non-intrusive diagnostics of atomic or molecular densities and velocity distributions in plasma applications. With regard to electric space propulsion, one focus is on the investigation of rare gases such as xenon or krypton, which are currently the favored propellants in gridded ion- and Hall-effect thrusters. For gridded ion engines, diagnostics of neutral atoms is of interest since charge-exchange processes between neutrals and ions are the main driver of accelerator grid erosion, which limits the lifetime of a gridded ion thruster. Extending the capabilities of the advanced electric propulsion diagnostics platform which has been developed by the IOM and partners, single- and two-photon absorption laser-induced fluorescence diagnostics have been set-up recently at our institute. Both experimental set-ups, and as a series of first applications, measurements of krypton neutrals in the plume of the radiofrequency ion thruster RIT-10 (ArianeGroup GmbH), and xenon neutrals within the discharge chamber of a gridded radiofrequency ion source developed at IOM, are presented.

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Section: Introductionmentioning

confidence: 99%

Single- and two-photon absorption laser-induced fluorescence spectroscopy in rare gases for gridded ion thruster diagnostics

et al. 2022

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“…In the past, several studies have used 130 nm radiation for exciting O( 3 P) atoms to the 3s 3 S o 1 state prior to detection. It is, for instance, possible to detect laser-induced fluorescence after this excitation step [10]. Another method uses a second laser with a wavelength of 305 nm to excite the intermediate 3s state to high-lying Rydberg states which are then field ionised in a time-of-flight Oatom Rydberg tagging experiment [11,12].…”

Section: Introductionmentioning

confidence: 99%

Laser ionisation detection of O(³P_j) atoms in the VUV; application to photodissociation of O₂

et al. 2021

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Detection of O( 3 P j ) atoms using one-photon resonant excitation to the 3s 3 S o 1 state at ∼130 nm followed by near-threshold ionisation, i.e. 1 + 1' resonance-enhanced multi-photon ionisation, has been investigated. The aim was to achieve low ion recoil, improved sensitivity, and reliable angular momentum polarisation information, with an as simple as possible laser setup. An efficient 1 + 1' scheme has been found where the VUV light for the first step is generated by difference frequency (2ω 1 − ω 2 ) VUV generation, and the ionisation step 1' uses 2ω 2 around 289 nm. The presented scheme induces 9 m/s recoil of the O + ion using a two-dye laser system, and zero recoil should be possible by generating 302 nm radiation with a third dye laser. While this approach is much more sensitive than a previous 1 + 1' scheme using 212.6 nm for the 1' step, we found that the relatively intense radiation of the 2ω 2 beam does not saturate the 1' step. To test the ability of this scheme to accurately determine branching ratios, fine structure yields, and angular distributions including polarisation information, it has been applied to O 2 photodissociation around 130 nm with subsequent O( 3 P j ) fragment detection.

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“…In the past, several studies have used 130 nm radiation for exciting O( 3 P ) atoms to the 3s 3 S o 1 state prior to detection. It is, for instance, possible to detect laser-induced fluorescence after this excitation step [10]. Another method uses a second laser with a wavelength of 305 nm to excite the intermediate 3s state to high-lying Rydberg states which are then field ionized in a time-of-flight O-atom Rydberg tagging experiment [11,12].…”

Section: Introductionmentioning

confidence: 99%

Laser ionization detection of O($^3P_j$) atoms in the VUV; application to photodissociation of O$_2$

Wang,

Parker,

van de Meerakker

et al. 2021

Preprint

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Detection of nascent O( 3 Pj, j = 2, 1, 0) atoms using one-photon resonant excitation to the 3s 3 S o 1 state at ∼130 nm followed by near-threshold ionization, i. e., 1 + 1' resonance enhanced multi-photon ionization (REMPI), has been investigated. The aim was to achieve low ion recoil, improved sensitivity, and reliable angular momentum polarization information, with an as simple as possible laser setup. An efficient 1 + 1' scheme has been found where the VUV light for the first step 1 is generated by difference frequency (2ω1 − ω2) VUV generation by four wave mixing in Kr gas, and the ionization step 1' uses 2ω2 at 289 nm. The presented scheme induces 9 m/s recoil of the O + ion using a two-dye laser system, and zero recoil should be possible by generating 302 nm radiation with a third dye laser. While this approach is much more sensitive than a previous 1 + 1' scheme using 212.6 nm for the 1' step, we found that the relatively intense 289 nm radiation does not saturate the 1' step. In order to test the ability of this scheme to accurately determine branching ratios, fine structure yields, and angular distributions including polarization information, it has been applied to O2 photodissociation around 130 nm with subsequent O( 3 Pj) fragment detection.

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Detection of atomic oxygen by laser-induced fluorescence spectroscopy at 130 nm

Cited by 17 publications

References 14 publications

Single- and two-photon absorption laser-induced fluorescence spectroscopy in rare gases for gridded ion thruster diagnostics

Single- and two-photon absorption laser-induced fluorescence spectroscopy in rare gases for gridded ion thruster diagnostics

Laser ionisation detection of O(³P_j) atoms in the VUV; application to photodissociation of O₂

Laser ionization detection of O($^3P_j$) atoms in the VUV; application to photodissociation of O$_2$

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Detection of atomic oxygen by laser-induced fluorescence spectroscopy at 130 nm

Cited by 17 publications

References 14 publications

Single- and two-photon absorption laser-induced fluorescence spectroscopy in rare gases for gridded ion thruster diagnostics

Single- and two-photon absorption laser-induced fluorescence spectroscopy in rare gases for gridded ion thruster diagnostics

Laser ionisation detection of O(3Pj) atoms in the VUV; application to photodissociation of O2

Laser ionization detection of O($^3P_j$) atoms in the VUV; application to photodissociation of O$_2$

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Laser ionisation detection of O(³P_j) atoms in the VUV; application to photodissociation of O₂