Measurement of the populations of metastable levels in gadolinium vapor by diode laser-based UV and near-IR absorption spectroscopy

Jung, Euo Chang; Ko, Kwang–Hoon; Rho, Sipyo; Lim, Changhwan; Kim, Cheol‐Jung

doi:10.1016/s0030-4018(02)01961-2

Cited by 8 publications

(6 citation statements)

References 16 publications

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“…Hence, CRDS with diode laser sources is an almost universal technique for monitoring plasma species, temperature and other parameters. Determination of a variety of elements by atomic absorption with the tunable diode lasers have been reported (e.g., Al, 14 Ba, 15 Ca, 16 Cr, 17 Cs, 18 Cu, 19 Gd, 20 Hg, 21 I, 22 In, 23 K, 24 La, 25 Li, 26 Mn, 27 Pb, 24 Rb, 11,18 Sm, 28 U, 29 Y, 30 Zr 31 ) and many more listed 32 as possible at doubled laser frequency: Ag, Co, Eu, Fe, Ga, Hf, Ho, Lu, Mo, Nb, Nd, Ni, Os, Re, Rh, Ru, Sc, Tb, Th, Ti, Tl, Tm, V, and W. Densities of common molecular contaminants and major plasma constituents, such as H 2 O, OH, O 2 , CO, CO 2 , CH 4 , NH 3 , HCl, and HBr have also been measured by diode laser based absorption. [33][34][35][36][37][38][39] Measurement of the CF 2 and CF 4 etching-related molecules at combination bands (3ν 1 +ν 3 ) and (ν 1 +3ν 3 ) around 2.12 µm by cw-CRDS has been suggested.…”

Section: Continuous-wave Cavity Ring-down Spectroscopymentioning

confidence: 99%

Sensor for monitoring plasma parameters

2004

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A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used as part of sensing hardware for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3, 45, and 90% N2 in Ar) at pressure 0.5-70 Pa and inductive power of 100 and 300 W. The results were compared to rotational temperature derived from the N2 emission at the (0,0) transition of the C - B system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar* and N2*) that varied depending on conditions. A two-dimensional, two-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro- and nano-fabrication plasma processing, thus enabling the diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable tracking the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma.Comment: Presented at the Photonics West conference, Lasers and Applications in Science and Technology, San Jose, CA, January 2004. This version gives a more detailed introduction on diode lasers as diagnostic tool for micro/nano-fabrication. A follow-up paper published in Plasma Sources Sci. Technol., v.13, 691-700 (2004) featured improvements in plasma simulatio

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Section: Continuous-wave Cavity Ring-down Spectroscopymentioning

confidence: 99%

Sensor for monitoring plasma parameters

2004

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“…Journal of Spectroscopy optogalvanic laser absorption spectroscopy [19] and population density measurements [20] in the meta-stable levels of Gd I. IS and hfs studies have been done by Jia et al [21] in high lying odd-parity levels of Gd I usig resonantly enhanced Doppler-free two-photon spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Experimental Studies on Electronic Configuration Mixing for the Even-Parity Levels of Gd I Using Isotope Shifts Recorded in the Visible Region with FTS

Ankush

Deo

2013

Journal of Spectroscopy

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Electronic configuration (4f 7 6s 2 6p + 4f 7 5d6s6p + 4f 7 5d 2 6p) mixing studies in the high even-parity energy levels of Gd I spectrum have been carried out on the basis of isotope shift (IS) Δ 156,160 data recorded in 49 spectral lines partially in the visible wavelength region on Fourier Transform Spectrometer (FTS) and the relevant spectral line IS data available in the literature. We employed "Sharing rule" to the experimentally observed level isotope shifts (LIS) of the even-parity levels for finding the percentage composition of each configuration being mixed. An FTS spectrum of Gd I in the region of 365-495 nm acquired employing the highly enriched Gd isotopes in liquid nitrogen cooled hollow cathode lamp (HCL) as a light source and photomultiplier tube as the detector. The studies of altogether 48 even-levels have revealed that amongst the 20 high even parity levels assigned previously to >95% 4f 7 5d6s6p configuration, 10 levels have agreed very well whereas 7 have exhibited large contribution of 4f 7 5d6s6p configuration compared to 4f 7 5d 2 6p configuration and 3 levels have equal contribution of 4f 7 5d6s6p and 4f 7 5d 2 6p configurations. Out of 8 unassigned levels, 6 have dominant 4f 7 5d6s6p configuration compared to 4f 7 5d 2 6p configuration and the remaining two have dominancy in 4f 7 5d 2 6p configuration.

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“…In such experiments where state resolved ͑ground, metastable, etc.͒ atom population needs to be measured, methods such as laser-induced fluorescence, 15 laser absorption spectroscopy ͑dye and diode lasers͒, [16][17][18][19][20][21] and resonance photoionization technique 22 have been used. Dye laser systems have the advantage of tunability over a broad wavelength range but they are expensive and cumbersome for large-scale applications.…”

Section: Introductionmentioning

confidence: 99%

Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation

Majumder

Dikshit

Bhatia

et al. 2008

Review of Scientific Instruments

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State resolved atom population of metal vapor having low-lying metastable states departs from equilibrium value. It needs to be experimentally investigated. This paper reports the use of hollow cathode lamp based atomic absorption spectroscopy technique to measure online the state resolved atom density (ground and metastable) of metal vapor in an atomic beam produced by a high power electron gun. In particular, the advantage of availability of multiwavelength emission in hollow cathode lamp is used to determine the atom density in different states. Here, several transitions pertaining to a given state have also been invoked to obtain the mean value of atom density thereby providing an opportunity for in situ averaging. It is observed that at higher source temperatures the atoms from metastable state relax to the ground state. This is ascribed to competing processes of atom-atom and electron-atom collisions. The formation of collision induced virtual source is inferred from measurement of atom density distribution profile along the width of the atomic beam. The total line-of-sight average atom density measured by absorption technique using hollow cathode lamp is compared to that measured by atomic vapor deposition method. The presence of collisions is further supported by determination of beaming exponent by numerically fitting the data.

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Measurement of the populations of metastable levels in gadolinium vapor by diode laser-based UV and near-IR absorption spectroscopy

Cited by 8 publications

References 16 publications

Sensor for monitoring plasma parameters

Sensor for monitoring plasma parameters

Experimental Studies on Electronic Configuration Mixing for the Even-Parity Levels of Gd I Using Isotope Shifts Recorded in the Visible Region with FTS

Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation

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