Sputter erosion measurements of titanium and molybdenum by cavity ring-down spectroscopy

Surla, V.; Wilbur, P. J.; Johnson, Mark L.; Williams, John D.; Yalin, Azer P.

doi:10.1063/1.1786354

Cited by 18 publications

(21 citation statements)

References 9 publications

(4 reference statements)

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“…The approach presented here uses cavity ring-down spectroscopy (CRDS), a technique which is also based on LAS but which provides significantly improved sensitivity through the use of an optical cavity. Past work has developed and validated CRDS measurements of sputtered refractory metal and boron nitride targets exposed to ion beams [23][24][25][26][27][28]. Here, we show for the first time that the method can be extended to a CRDS erosion sensor for Hall thrusters, thereby providing a new method for thruster development and life testing.…”

mentioning

confidence: 81%

Sputter Erosion Sensor for Anode Layer-Type Hall Thrusters Using Cavity Ring-Down Spectroscopy

Yamamoto

Tao

Rubin

et al. 2010

Journal of Propulsion and Power

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We report the development of a sputter erosion monitoring system to study Hall thruster lifetime and contamination. The laser-based sensor uses the continuous-wave cavity ring-down spectroscopy technique and allows for in situ measurements in near-real time. The continuous-wave cavity ring-down spectroscopy technique diagnostic allows direct probing of sputter products in their ground state, thereby providing a reliable quantitative measure of their overall number density. Combining the number density of sputtered particles with their velocity allows determination of the flux of sputtered particles and erosion rate. We perform proof of principle experiments, in which sputtered manganese atoms from the acceleration channel of an anode layer-type Hall thruster are measured. The measurement strategy is to detect the manganese atoms via an absorption line from the ground state at a wavelength of 403.076 nm (air). The measured path-integrated number density of sputtered manganese atoms is 1:7 0:3 10 13 m 2 for an argon anode mass flow rate of 2:08 mg=s and a discharge voltage of 250 V. A finite element sputter model is used to compare the cavity ring-down spectroscopy results against validating mass loss measurements and shows good agreement. Nomenclature A ki = Einstein A coefficient, 1=s Abs = absorbance c = speed of light, 2:998 10 8 m=s E b = binding energy, J E i = energy of state i, J E k = energy of state k, J g i = degeneracy of state i g k = degeneracy of state k k = absorption coefficient, m 1 l = length of the ring-down cavity, m l abs = path length of absorbing species, m N i = lower-state concentration, m 3 R = mirror reflectivity St; = ring-down signal as a function of time and laser frequency S 0 = initial ring-down signal x = position along the optical axis, m = laser frequency, Hz ki = resonant frequency of transition, Hz = ring-down time, s 0 = empty cavity ring-down time, s

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mentioning

confidence: 81%

Sputter Erosion Sensor for Anode Layer-Type Hall Thrusters Using Cavity Ring-Down Spectroscopy

Yamamoto

Tao

Rubin

et al. 2010

Journal of Propulsion and Power

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“…Recently, CRDS has been used to study sputter erosion of a metallic target. (36,37) In those studies, the ion beam source and the target were housed in a vacuum chamber with a background pressure of 10 −6 -10 −7 Torr. Energetic argon ions bombarded a metallic target and elements were generated around the surface of the target.…”

Section: Combustion Flame Chemistry and Plasma Diagnosticsmentioning

confidence: 99%

Cavity Ringdown Laser Absorption Spectroscopy

Wang

Miller

Winstead

2008

Encyclopedia of Analytical Chemistry

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Cavity ringdown spectroscopy (CRDS) has developed rapidly during the last two decades and has been implemented for a variety of applications ranging from fundamental spectroscopic studies, trace chemical detection for environmental monitoring, combustion flame chemistry and plasma diagnostics, elemental and isotopic measurements, breath gas analysis, and fiber ringdown chemical and physical sensor development. A host of chemical species, including atoms, ions, molecules, clusters, and free radicals, have been studied by CRDS. The experimental ringdown scheme has also evolved from an original mirror‐based format to various new forms for detection and analysis of analytes in either gas phase or liquid solutions. Recent research effort has also extended the CRDS approach for fiber optical sensor development. CRDS has become a mature spectrometric technique for a range of prototype and commercial instrumentation. This article provides a review of the latest developments in CRDS applications, specifically emphasizing new trends in elemental and isotopic analysis, plasma diagnostics, breath gas analysis, and new fiber ringdown techniques for sensor development. The introduction of cutting‐edge laser sources into CRDS methods, the combination of CRDS with conventional analytical tools, and current CRDS instrumentation are also briefly discussed.

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“…Detailed reviews of the technique may be found in references 28 and 29. Our previous development of CRDS for sputter diagnostics has been previously described [24][25][26][27] . As shown in Fig.1, the absorbing sample is contained within a high-finesse optical cavity typically formed from two (or three) highreflectivity (R) mirrors with R ~0.9999.…”

Section: Cavity Ring-down Spectroscopymentioning

confidence: 99%

“…The work presented here builds upon our previous development of cavity ring-down spectroscopy (CRDS) for sputtering measurements [24][25][26][27] . CRDS is a highly sensitive laser-based absorption method allowing species-specific measurement of concentrations of trace species.…”

Section: Introductionmentioning

confidence: 99%

Species-Specific Sputtering Measurements with Cavity Ring-Down Spectroscopy (Preprint)

Surla¹,

Tao²,

Yalin³

2007

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 3. DATES COVERED (From -To) Edwards AFB CA 93524-7013 SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) Air Force Research Laboratory (AFMC) AFRL/PRS SPONSOR/MONITOR'S Pollux Drive NUMBER(S) Edwards AFB CA 93524-7048 AFRL-PR-ED-TP-2007-275 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited (PA #07231A) SUPPLEMENTARY NOTESFor presentation at the 43 rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Cincinnati, OH, 8-11 July 2007. ABSTRACTWe report sputtering studies using cavity ring-down spectroscopy (CRDS). The high sensitivity of the technique and its non-intrusive nature make it amenable to both in situ device studies as well as basic characterization studies. We provide demonstrative measurements of sputtered particles showing the ability to determine species-specific number density and velocity. We summarize a spatial-scanning approach for differential sputter yield measurements and give a measurement example based on a tantalum target. We discuss the use of CRDS for measurement of multi-component materials and provide experimental results for detection of a Fe-Mn target as well as a proposed detection scheme for boron nitride.

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Sputter erosion measurements of titanium and molybdenum by cavity ring-down spectroscopy

Cited by 18 publications

References 9 publications

Sputter Erosion Sensor for Anode Layer-Type Hall Thrusters Using Cavity Ring-Down Spectroscopy

Sputter Erosion Sensor for Anode Layer-Type Hall Thrusters Using Cavity Ring-Down Spectroscopy

Cavity Ringdown Laser Absorption Spectroscopy

Species-Specific Sputtering Measurements with Cavity Ring-Down Spectroscopy (Preprint)

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