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Da Ros A, Vezinet D, Colledani G, Fenzi-Bonizec C, Moureau G, Bertschinger G. Electron and ion temperature measurement with a new x-ray imaging crystal spectrometer on WEST. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:043505. [PMID: 38587445 DOI: 10.1063/5.0179905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 03/21/2024] [Indexed: 04/09/2024]
Abstract
A new x-ray imaging crystal spectrometer (XICS) has been installed, aligned, and used during experimental campaigns on the WEST tokamak. It has three interchangeable crystals for measuring the Ar XVII, Ar XVIII, and Fe XXV spectra, respectively. A patented rotating table holding the crystals is used to monitor the crystal facing the plasma remotely and without changing the position of the camera. Here, the focus is made on the Ar XVII spectrum, between 3.93 and 4.00 Å. The design of the diagnostic is presented, and a synthetic diagnostic, implemented with the Python library ToFu, is used to show the instrument's operational performance and limits. The instrument function exhibits the following two main features: a distortion for the Ar XVII spectrum, presumably due to the crystal manufacturing in two parts, and the measurement of three W spectral lines on the Ar XVI spectrum. Line of sight-integrated profiles of the electron and ion temperatures are thus extracted from the Ar XVII spectrum from two distinct spectral line ratios and from the Doppler broadening, respectively. The bremsstrahlung emission and the W line measurements are the two main limitations to compute the electron temperature. Tomographic inversions are also implemented with the library ToFu and used in order to obtain the local electron and ion temperature profiles, which are compared to other measurements from the WEST ECE (electron cyclotron emission) diagnostic. It is shown that both the XICS line-integrated and ECE Te measurements are in better agreement. Systematic differences are shown between the electron temperature profiles calculated from the two available line ratios.
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Affiliation(s)
- A Da Ros
- CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
| | - D Vezinet
- CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
| | - G Colledani
- CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
| | | | - G Moureau
- CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
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2
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Electron self-energy corrections using the Welton concept for atomic structure calculations. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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3
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Paul N, Bian G, Azuma T, Okada S, Indelicato P. Testing Quantum Electrodynamics with Exotic Atoms. PHYSICAL REVIEW LETTERS 2021; 126:173001. [PMID: 33988393 DOI: 10.1103/physrevlett.126.173001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/17/2020] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Precision study of few-electron, high-Z ions is a privileged field for probing high-field, bound-state quantum electrodynamics (BSQED). However, the accuracy of such tests is plagued by nuclear uncertainties, which are often larger than the BSQED effects under investigation. We propose an alternative method with exotic atoms and show that transitions may be found between circular Rydberg states where nuclear contributions are vanishing while BSQED effects remain large. When probed with newly available quantum sensing detectors, these systems offer gains in sensitivity of 1 to 2 orders of magnitude, while the mean electric field largely exceeds the Schwinger limit.
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Affiliation(s)
- Nancy Paul
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, Case 74; 4, place Jussieu, F-75005 Paris, France
| | - Guojie Bian
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, Case 74; 4, place Jussieu, F-75005 Paris, France
- Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, 100088 Beijing, China
| | - Toshiyuki Azuma
- Atomic, Molecular and Optical Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Shinji Okada
- Chubu University, Kasugai, Aichi 487-8501, Japan
| | - Paul Indelicato
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, Case 74; 4, place Jussieu, F-75005 Paris, France
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Sun YR, Hu SM. Precision spectroscopy of atomic helium. Natl Sci Rev 2020; 7:1818-1827. [PMID: 34691519 PMCID: PMC8288801 DOI: 10.1093/nsr/nwaa216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/15/2019] [Accepted: 03/13/2020] [Indexed: 11/13/2022] Open
Abstract
Helium is a prototype three-body system and has long been a model system for developing quantum mechanics theory and computational methods. The fine-structure splitting in the 23P state of helium is considered to be the most suitable for determining the fine-structure constant α in atoms. After more than 50 years of efforts by many theorists and experimentalists, we are now working toward a determination of α with an accuracy of a few parts per billion, which can be compared to the results obtained by entirely different methods to verify the self-consistency of quantum electrodynamics. Moreover, the precision spectroscopy of helium allows determination of the nuclear charge radius, and it is expected to help resolve the 'proton radius puzzle'. In this review, we introduce the latest developments in the precision spectroscopy of the helium atom, especially the discrepancies among theoretical and experimental results, and give an outlook on future progress.
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Affiliation(s)
- Yu R Sun
- Hefei National Laboratory for Physical Sciences at Microscale, iChem Center, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Shui-Ming Hu
- Hefei National Laboratory for Physical Sciences at Microscale, iChem Center, University of Science and Technology of China, Hefei 230026, China
- CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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5
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Salhi DE, Ben Nasr S, Jelassi H. MCDHF/RCI extended calculations of energy levels, radiative properties, AJ, BJ hyperfine interaction constants, and Landé gJ-factors for Ar XVII. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108817] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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6
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Chen Z. Polarization of x-ray radiation after electron-impact excitation of ions in plasmas. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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7
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A vacuum double-crystal spectrometer for reference-free X-ray spectroscopy of highly charged ions. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2014.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Epp SW. Comment on "Testing three-body quantum electrodynamics with trapped Ti20+ ions: evidence for a Z-dependent divergence between experiment and calculation". PHYSICAL REVIEW LETTERS 2013; 110:159301. [PMID: 25167321 DOI: 10.1103/physrevlett.110.159301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Indexed: 06/03/2023]
Affiliation(s)
- S W Epp
- Max Planck Advanced Study Group, Center for Free-Electron Laser Science, 22607 Hamburg, Germany and Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
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Chantler CT, Kinnane MN, Gillaspy JD, Hudson LT, Payne AT, Smale LF, Henins A, Pomeroy JM, Tan JN, Kimpton JA, Takacs E, Makonyi K. Testing three-body quantum electrodynamics with trapped Ti20+ ions: evidence for a Z-dependent divergence between experiment and calculation. PHYSICAL REVIEW LETTERS 2012; 109:153001. [PMID: 23102303 DOI: 10.1103/physrevlett.109.153001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Indexed: 06/01/2023]
Abstract
We report a new test of quantum electrodynamics (QED) for the w (1s2p(1)P(1)→1s(2)(1)S(0)) x-ray resonance line transition energy in heliumlike titanium. This measurement is one of few sensitive to two-electron QED contributions. Systematic errors such as Doppler shifts are minimized in our experiment by trapping and stripping Ti atoms in an electron beam ion trap and by applying absolute wavelength standards to calibrate the dispersion function of a curved-crystal spectrometer. We also report a more general systematic discrepancy between QED theory and experiment for the w transition energy in heliumlike ions for Z>20. When all of the data available in the literature for Z=16-92 are taken into account, the divergence is seen to grow as approximately Z(3) with a statistical significance on the coefficient that rises to the level of 5 standard deviations. Our result for titanium alone, 4749.85(7) eV for the w line, deviates from the most recent ab initio prediction by 3 times our experimental uncertainty and by more than 10 times the currently estimated uncertainty in the theoretical prediction.
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Affiliation(s)
- C T Chantler
- School of Physics, The University of Melbourne, Parkville 3010, Australia.
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Amaro P, Schlesser S, Guerra M, Le Bigot EO, Isac JM, Travers P, Santos JP, Szabo CI, Gumberidze A, Indelicato P. Absolute measurement of the relativistic magnetic dipole transition energy in heliumlike argon. PHYSICAL REVIEW LETTERS 2012; 109:043005. [PMID: 23006085 DOI: 10.1103/physrevlett.109.043005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Indexed: 05/22/2023]
Abstract
The 1s2s (3)S(1)→1s(2) (1)S(0) relativistic magnetic dipole transition in heliumlike argon, emitted by the plasma of an electron-cyclotron resonance ion source, has been measured using a double-flat crystal x-ray spectrometer. Such a spectrometer, used for the first time on a highly charged ion transition, provides absolute (reference-free) measurements in the x-ray domain. We find a transition energy of 3104.1605(77) eV (2.5 ppm accuracy). This value is the most accurate, reference-free measurement done for such a transition and is in good agreement with recent QED predictions.
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Affiliation(s)
- Pedro Amaro
- Laboratoire Kastler Brossel, Ecole Normale Supérieure, CNRS, Université Pierre et Marie Curie-Paris 6, Case 74, 4 Place Jussieu, F-75005 Paris, France
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11
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Kubicek K, Braun J, Bruhns H, López-Urrutia JRC, Mokler PH, Ullrich J. High-precision laser-assisted absolute determination of x-ray diffraction angles. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:013102. [PMID: 22299924 DOI: 10.1063/1.3662412] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
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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Affiliation(s)
- K Kubicek
- Max-Planck-Institute for Nuclear Physics, Heidelberg, Germany.
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Thorn DB, Gu MF, Brown GV, Beiersdorfer P, Porter FS, Kilbourne CA, Kelley RL. Precision measurement of the K-shell spectrum from highly charged xenon with an array of X-ray calorimeters. PHYSICAL REVIEW LETTERS 2009; 103:163001. [PMID: 19905691 DOI: 10.1103/physrevlett.103.163001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Indexed: 05/28/2023]
Abstract
We present a measurement of the K-shell spectrum from highly charged xenon ions recorded with a high-energy x-ray calorimeter spectrometer array that can distinguish between various theories for the atomic structure of the two electron system. The array was designed to provide high resolution with high quantum efficiency in the 10-60 keV x-ray range which allows us to resolve blends that afflicted previous measurements. A precision of better than 2 eV was achieved in the measurement of the Xe52+ and Xe53+ K-shell transitions located near 31 keV, which is an order of magnitude better than previously reported.
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Affiliation(s)
- Daniel B Thorn
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
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Silze A, Zschornack G, Ovsyannikov VP, Ullmann F. Properties of the electron beam in a room-temperature electron beam ion source investigated by position sensitive x-ray detection. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:083302. [PMID: 19044341 DOI: 10.1063/1.2960568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The evolution of the charge state distribution inside an electron beam ion source or trap (EBIS/T) is determined by interactions of the electron beam with the ions in the trap region. Hence, detailed information about the electron beam is required for evaluations of spectroscopic and ion extraction measurements performed at EBIS/T facilities. This article presents the results of investigations on the electron beam properties of an ion source of the Dresden EBIS type. For the first time theoretical predictions of the shape of the beam were tested for a noncryogenic EBIS working with low magnetic flux densities provided by permanent magnets. Position and width of the electron beam were measured at different electron energies showing an oscillation in the beam structure. At an energy of E(e)=16 keV and an emission current of I(e)=30 mA the beam is compressed to a radius of r(e)=57 mum (80% current). This refers to an average current density of j(e)=232 A/cm(2).
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Affiliation(s)
- A Silze
- Institut fur Angewandte Physik, Technische Universitat Dresden, Helmholtzstrasse 10, D-01062 Dresden, Germany.
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14
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Lapierre A, Crespo López-Urrutia JR, Baumann TM, Epp SW, Gonchar A, González Martínez AJ, Liang G, Rohr A, Soria Orts R, Simon MC, Tawara H, Versteegen R, Ullrich J. Compact soft x-ray spectrometer for plasma diagnostics at the Heidelberg Electron Beam Ion Trap. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:123105. [PMID: 18163718 DOI: 10.1063/1.2818808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A compact flat-field soft x-ray grazing-incidence grating spectrometer equipped with a cryogenically cooled back-illuminated charge-coupled device camera was built and implemented at the Heidelberg Electron Beam Ion Trap. The instrument spans the spectral region from 1 to 37 nm using two different gratings. In slitless operation mode, it directly images a radiation source, in this case ions confined in an electron beam ion trap, with high efficiency and reaching hereby a resolving power of lambda/Deltalambda approximately =130 at 2 nm and of lambda/Deltalambda approximately =600 at 28 nm. Capable of automatized operation, its low noise and excellent stability make it an ideal instrument not only for spectroscopic diagnostics requiring wide spectral coverage but also for precision wavelength measurements.
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Affiliation(s)
- A Lapierre
- Max-Planck Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany
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