4p64d8–(4d75p + 4d74f + 4p54d9) Transitions in Xe XI

Churilov, S S; Joshi, Y N; Reader, Joseph; Kildiyarova, R R

doi:10.1088/0031-8949/70/2-3/009

Cited by 39 publications

(48 citation statements)

References 31 publications

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“…In the EBIT spectra, the observed UTA peaks at an energy of 10.84 nm, which is slightly higher than the observed emission peak of Xe XI at 11.17 nm [39]. The count rates within a 0.27 nm band centred here are compared with the counts at 13.5 and 11.17 nm in table 1.…”

Section: Resultsmentioning

confidence: 78%

“…There are also features in the 13.5 nm band that are not evident in the 500 eV spectrum. These observations are consistent with the production of higher charge states as the energy of the electron beam is increased.In the EBIT spectra, the observed UTA peaks at an energy of 10.84 nm, which is slightly higher than the observed emission peak of Xe XI at 11.17 nm [39]. The count rates within a 0.27 nm band centred here are compared with the counts at 13.5 and 11.17 nm in table 1.…”

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confidence: 78%

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UTA versus line emission for EUVL: studies on xenon emission at the NIST EBIT

Fahy¹,

Dunne²,

McKinney³

et al. 2004

J. Phys. D: Appl. Phys.

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Abstract:Spectra from xenon ions have been recorded at the NIST EBIT and the emission into a 2% bandwidth at 13.5 nm arising from 4d_5p transitions compared with that from 4d_4f and 4p_4d transitions in Xe XI and also with that obtained from the unresolved transition array (UTA) observed to peak just below 11 nm. It was found that an improvement of a factor of five could be gained in photon yield using the UTA rather than the 4d_5p emission. The results are compared with atomic structure calculations and imply that a significant gain in efficiency should be obtained using tin, in which the emission at 13.5 nm comes from a similar UTA, rather than xenon as an EUVL source material. BACKGROUND:The search for the optimum radiation source at 13.5 nm is one of the main challenges in EUV physics today. Currently the quest is to find a source with a conversion efficiency (CE) of 3% into 2% bandwidth as defined by the needs of the microelectronic industry [1]. The earliest work was performed with laser produced plasmas generated on solid targets. Kauffman et al. [2] attained a CE close to 1% into 3% bandwidth using 7.5 ns, 300 mJ frequency doubled Nd:YAG pulses focussed to a power density of 2×10 . In their work they performed an extensive survey of the emission from a large range of elements and found that the emission at the required wavelength peaked near tin. At higher power densities they noted that the intensity decreased. Shevelko et al. [4] also undertook an extensive study of the spectra of a large number of elements from laser produced plasmas with a KrF excimer laser focussed to a power density of 10 12 Wcm -2 onto planar targets including tin and found that the maximum intensity was in fact obtained for Ge and Re under these conditions. So early work already pointed to the sensitivity of the emission of specific elements to laser power density.In order to avoid the debris problems associated with solid targets other target materials were sought with strong emission in the 13-14 nm region. Jin and Richardson [5] used mass limited water ice targets, where the emission is from the O VI lines near 2 13 nm, to limit the debris. However, all of their early work with mass-limited targets produced significant levels of debris both in the form of ions and particulates of various sizes. The need to reduce particulate emission led to the choice of xenon. There is a line group between 13-14 nm in the spectrum of Xe which has been shown by a number of researchers to arise from 4d 8 _ 4d 7 5p transitions in Xe XI [6]. These lines have recently been identified by Churilov et al. [7] by comparison of new very high resolution data with atomic structure calculations using the suite of codes developed by Cowan [8]. Considerable work has been expended on exploring the feasibility of using laser produced plasmas of xenon clusters produced by supersonic jets or gas puffs from nozzles or solid xenon targets [9]. The highest conversion efficiencies (1.2% into 2% bandwidth) have been achieved using solid xenon by Shields et al. [1...

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Section: Resultsmentioning

confidence: 78%

mentioning

confidence: 78%

UTA versus line emission for EUVL: studies on xenon emission at the NIST EBIT

Fahy¹,

Dunne²,

McKinney³

et al. 2004

J. Phys. D: Appl. Phys.

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“…The wavelength calibration of the spectra has been done based on recorded and identified lithium-like lines from the oxygen plasma. The grazing incidence spectrograph (GIS) spectra were determined with an accuracy of 0.5 Å in comparison with the theoretically calculated lines by Churilov et al [35]. The spectral resolution of the GIS was about 0.2 Å in the EUV range and that of the transmission grating spectrograph (TGS) was about 0.6 nm.…”

Section: Experimental Conditionsmentioning

confidence: 97%

“…10b indicates the highest T e observed in our experiments on EUV generation. The spectra are wavelength-calibrated with the use of published Xe +10 peaks [35].…”

Section: Measurements With the Transmission Grating Spectrographmentioning

confidence: 99%

Characterization and optimization of the laser-produced plasma EUV source at 13.5 nm based on a double-stream Xe/He gas puff target

et al. 2010

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The paper describes a debris-free, efficient laserproduced plasma source emitting EUV radiation. The source is based on a double-stream Xe/He gas-puff. Its properties and spectroscopic signatures are characterized and discussed. The spatio-spectral features of the EUV emission are investigated. We show a large body of results related to the intensity and brightness of the EUV emission, its spatial, temporal, and angular behavior and the effect of the repetition rate as well. A conversion efficiency of laser energy into EUV in-band energy at 13.5 nm of 0.42% has been gained. The electron temperature and electron density of the source were estimated by means of a novel method using the FLY code. The experimental data and the Hullac code calculations are compared and discussed. The source is well suited for EUV metrology purposes. The potential of the source for R. Rakowski ( ) ·

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“…The analyses of the UTA structure for tin and xenon are not discussed here because they have already been done in detail [6,18,19,20]. In this study, assignments of the strong discrete lines from tin and xenon ions, and the complicated broad features of tungsten ions have been performed with the help of comparisons with the previous experimental results, the experimental spectra in charge exchange collisions [21] and the theoretical calculations by Cowan code.…”

Section: Analysesmentioning

confidence: 99%

Measurement of EUV Spectra from High Z Elements in the Large Helical Device

Suzuki¹,

Katō²,

Sakaue³

et al. 2011

AIP Conference Proceedings

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Abstract. Extreme ultra-violet (EUV) emission spectra from highly charged tin, xenon and tungsten ions have been measured in optically thin high-temperature plasmas produced in the Large Helical Device (LHD) at the National Institute for Fusion Science by using a grazing incidence spectrometer and a tracer-encapsulated solid pellet (TESPEL) injector. Quasi-continuous spectral features arising from unresolved transition array (UTA) of open 4d subshell ions were commonly observed for tin, xenon and tungsten around 13.5, 11, and 5 nm, respectively, when edge plasma was cooled enough. The spectral appearance obviously depends on edge electron temperature and atomic number. In the case of intermediate edge temperature, sharp discrete lines from highly charged open 4s or 4p subshell ions are clearly observed for tin and xenon in longer wavelength side of the UTAs but not for tungsten. Assignments of the strong discrete lines have been performed with the help of comparisons with the other experimental data and the theoretical calculations by Cowan code. Contribution of open 4f subshell ions should also be considered to interpret the whole spectra from tungsten ions.

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4p⁶4d⁸–(4d⁷5p + 4d⁷4f + 4p⁵4d⁹) Transitions in Xe XI

Cited by 39 publications

References 31 publications

UTA versus line emission for EUVL: studies on xenon emission at the NIST EBIT

UTA versus line emission for EUVL: studies on xenon emission at the NIST EBIT

Characterization and optimization of the laser-produced plasma EUV source at 13.5 nm based on a double-stream Xe/He gas puff target

Measurement of EUV Spectra from High Z Elements in the Large Helical Device

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