The ITER core imaging x-ray spectrometer: X-ray calorimeter performance

Beiersdörfer, P.; Brown, G. V.; Clementson, J.; Dunn, James P.; Morris, Kevin L.; Wang, E.; Kelley, R. L.; Kilbourne, Caroline A.; Porter, F. S.; Bitter, M.; Feder, R.; Hill, K. W.; Johnson, D.; Barnsley, R.

doi:10.1063/1.3495789

Cited by 19 publications

(10 citation statements)

References 11 publications

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“…Our work is motivated in part by renewed interest in the spectral emission of tungsten from magnetically confined high-temperature plasmas as illustrated by recent publications [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Tungsten will likely be a constituent of plasmas generated by the ITER (Latin, "the way") tokamak [17], and spectroscopic diagnostics are currently being developed that use radiation from tungsten ions for determining ITER plasma parameters [10,13,18].…”

Section: Introductionmentioning

confidence: 99%

“…Tungsten will likely be a constituent of plasmas generated by the ITER (Latin, "the way") tokamak [17], and spectroscopic diagnostics are currently being developed that use radiation from tungsten ions for determining ITER plasma parameters [10,13,18]. An overview of recent results from the Livermore WOLFRAM spectroscopy project was presented recently by Clementson et al [3], which includes experimental investigations at the EBIT-I and SuperEBIT electron beam ion traps.…”

Section: Introductionmentioning

confidence: 99%

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Relativistic many-body calculations of excitation energies, oscillator strengths, transition rates, and lifetimes in samariumlike ions

Safronova

Beiersdörfer

2013

Phys. Rev. A

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The unique atomic properties of samariumlike ions, not yet measured experimentally, are theoretically predicted and studied in this paper. Excitation energies, oscillator strengths, transition probabilities, and lifetimes are calculated for (5s 2 + 5p 2 + 5d 2 + 5s5d + 5s5g + 5p5f )-(5s5p + 5s5f + 5p5d + 5p5g) electric dipole transitions in Sm-like ions with nuclear charge Z ranging from 74 to 100. Relativistic many-body perturbation theory (RMBPT), including the Breit interaction, is used to evaluate retarded E1 matrix elements in length and velocity forms. The calculations start from a 1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 6 4d 10 4f 14 Dirac-Fock potential. First-order perturbation theory is used to obtain intermediate coupling coefficients, and the second-order RMBPT is used to determine the matrix elements. The contributions from negative-energy states are included in the second-order E1 matrix elements to achieve agreement between length-form and velocity-form amplitudes. The resulting transition energies and transition probabilities, and lifetimes for Sm-like W 12+ are compared with results obtained by the relativistic Hartree-Fock approximation (COWAN code) to estimate contributions of the 4f -core-excited states. Trends of excitation energies and oscillator strengths as the function of nuclear charge Z are shown graphically for selected states and transitions. This work provides a number of yet unmeasured atomic properties of these samariumlike ions for various applications and as a benchmark for testing theory.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Relativistic many-body calculations of excitation energies, oscillator strengths, transition rates, and lifetimes in samariumlike ions

Safronova

Beiersdörfer

2013

Phys. Rev. A

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“…Apart from that x-ray bolometers exhibit today a resolution near that of crystal spectrometers. [28][29][30][31][32] Here, however, wavelengths can be measured relatively only.…”

Section: Introductionmentioning

confidence: 99%

High-precision laser-assisted absolute determination of x-ray diffraction angles

Kubiček

Braun

Bruhns

et al. 2012

Review of Scientific Instruments

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A novel technique for absolute wavelength determination in high-precision crystal x-ray spectroscopy recently introduced has been upgraded reaching unprecedented accuracies. The method combines visible laser beams with the Bond method, where Bragg angles (θ and -θ) are determined without any x-ray reference lines. Using flat crystals this technique makes absolute x-ray wavelength measurements feasible even at low x-ray fluxes. The upgraded spectrometer has been used in combination with first experiments on the 1s2p(1)P(1) → 1s(2)(1)S(0) w-line in He-like argon. By resolving a minute curvature of the x-ray lines the accuracy reaches there the best ever reported value of 1.5 ppm. The result is sensitive to predicted second-order QED contributions at the level of two-electron screening and two-photon radiative diagrams and will allow for the first time to benchmark predicted binding energies for He-like ions at this level of precision.

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“…As a result, it was thought that the strongest line of the W 64+ spectrum provided an excellent means for measuring the plasma ion temperature and bulk ion velocity based on its broadening and shift [28,30]. Accurate knowledge of the rest energy of the line is thus of great importance for such diagnostic applications as bulk plasma velocity measurements.…”

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confidence: 99%

L-shell x-ray emission from neonlike W64+

et al. 2012

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We present high-resolution crystal spectroscopy measurements of the n = 3 → n = 2 L-shell x-ray transitions of neonlike W 64+ , which include seven electric dipole allowed transitions, two electric quadrupole transitions, and one magnetic quadrupole transition. The resulting wavelength data are compared to recent calculational results, allowing us to clearly distinguish between different theoretical approaches, which need to take into account not only substantial electron correlations effects but also radiative contributions, which in case of the transition from upper level (1s 2 2s 1/2 2p 6 3p 3/2) J=1 to the closed-shell neonlike ground state exceeds 20 eV. Best agreement is found with calculations utilizing the relativistic multi-reference Møller-Plesset approach. In addition to the emission from W 64+ , we have observed several innershell collisional satellite lines associated with oxygenlike W 66+ , fluorinelike W 65+ , sodiumlike W 63+ , and magnesiumlike W 62+ , which provide benchmarks for future calculations as well as for recent calculations using the relativistic many-body perturbation theory. The present measurements also provide accurate rest wavelengths for establishing the instrumental dispersion needed for future measurements of the core plasma motion in the ITER tokamak and show that the candidate W 64+ line for such measurements remains well isolated from neighboring collisional satellite lines even when broadened by the expected, high temperatures in this device.

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The ITER core imaging x-ray spectrometer: X-ray calorimeter performance

Cited by 19 publications

References 11 publications

Relativistic many-body calculations of excitation energies, oscillator strengths, transition rates, and lifetimes in samariumlike ions

Relativistic many-body calculations of excitation energies, oscillator strengths, transition rates, and lifetimes in samariumlike ions

High-precision laser-assisted absolute determination of x-ray diffraction angles

L-shell x-ray emission from neonlike W64+

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