Search

Your search keyword '"Spruck, K."' showing total 88 results
Start Over Author "Spruck, K."
88 results on '"Spruck, K."'

1. Electron-impact single ionisation of W$^{q+}$ ions: Experiment and theory for $\mathbf{11\leq q \leq 18}$

Author

Schury, D., Borovik, Jr., A., Ebinger, B., Jin, F., Spruck, K., Müller, A., and Schippers, S.

Subjects
Physics - Atomic Physics, Physics - Plasma Physics
Abstract

Absolute cross sections for electron-impact single ionisation (EISI) of multiply charged tungsten ions (W$^{q+}$) with charge states in the range $ 11 \leq q \leq 18$ in the electron-ion collision energy ranges from below the respective ionisation thresholds up to 1000~eV were measured employing the electron-ion crossed-beams method. In order to extend the results to higher energies, cross section calculations were performed using the subconfiguration-averaged distorted-wave (SCADW) method for electron-ion collision energies up to 150~keV. From the combined experimental and scaled theoretical cross sections rate coefficients were derived which are compared with the ones contained in the ADAS database and which are based on the configuration-averaged distorted wave (CADW) calculations of Loch et al. [Phys. Rev. A 72, 052716 (2005)]. Significant discrepancies were found at the temperatures where the ions investigated here are expected to form in collisionally ionised plasmas. These discrepancies are attributed to the limitations of the CADW approach and also the more detailed SCADW treatment which do not allow for a sufficiently accurate description of the EISI cross sections particularly at the ionisation thresholds., Comment: 14 pages, 4 figures, 4 tabels

Published
2019
Full Text
View/download PDF

2. Radiative rotational lifetimes and state-resolved relative detachment cross sections from photodetachment thermometry of molecular anions in a cryogenic storage ring

Author

Meyer, C., Becker, A., Blaum, K., Breitenfeldt, C., George, S., Göck, J., Grieser, M., Grussie, F., Guerin, E. A., von Hahn, R., Herwig, P., Krantz, C., Kreckel, H., Lion, J., Lohmann, S., Mishra, P. M., Novotný, O., O'Connor, A. P., Repnow, R., Saurabh, S., Schwalm, D., Schweikhard, L., Spruck, K., Kumar, S. Sunil, Vogel, S., and Wolf, A.

Subjects
Physics - Atomic Physics, Physics - Accelerator Physics, Physics - Chemical Physics
Abstract

Photodetachment thermometry on a beam of OH$^-$ in a cryogenic storage ring cooled to below 10 K is carried out using two-dimensional, frequency and time dependent photodetachment spectroscopy over 20 minutes of ion storage. In equilibrium with the low-level blackbody field, we find an effective radiative temperature near 15 K with about 90% of all ions in the rotational ground state. We measure the J = 1 natural lifetime (about 193 s) and determine the OH$^-$ rotational transition dipole moment with 1.5% uncertainty. We also measure rotationally dependent relative near-threshold photodetachment cross sections for photodetachment thermometry., Comment: Manuscript LaTeX with 5 pages, 3 figures, and 1 table plus LaTeX supplement with 12 pages, 3 figures and 3 tables. This article has been accepted by Physical Review Letters

Published
2017
Full Text
View/download PDF

3. Single-particle detection of products from atomic and molecular reactions in a cryogenic ion storage ring

Author

Krantz, C., Novotný, O., Becker, A., George, S., Grieser, M., von Hahn, R., Meyer, C., Schippers, S., Spruck, K., Vogel, S., and Wolf, A.

Subjects
Physics - Instrumentation and Detectors
Abstract

We have used a single-particle detector system, based on secondary electron emission, for counting low-energetic (~keV/u) massive products originating from atomic and molecular ion reactions in the electrostatic Cryogenic Storage Ring (CSR). The detector is movable within the cryogenic vacuum chamber of CSR, and was used to measure production rates of a variety of charged and neutral daughter particles. In operation at a temperature of ~6 K, the detector is characterised by a high dynamic range, combining a low dark event rate with good high-rate particle counting capability. On-line measurement of the pulse height distributions proved to be an important monitor of the detector response at low temperature. Statistical pulse-height analysis allows to infer the particle detection efficiency of the detector, which has been found to be close to unity also in cryogenic operation at 6 K., Comment: Accepted to Nuclear Inst. and Methods in Physics Research, A

Published
2017
Full Text
View/download PDF

4. Absolute rate coefficients for photorecombination of berylliumlike and boronlike silicon ions

Author

Bernhardt, D., Becker, A., Brandau, C., Grieser, M., Hahn, M., Krantz, C., Lestinsky, M., Novotný, O., Repnow, R., Savin, D. W., Spruck, K., Wolf, A., Müller, A., and Schippers, S.

Subjects
Physics - Atomic Physics
Abstract

We report measured rate coefficients for electron-ion recombination for Si10+ forming Si9+ and for Si9+ forming Si8+, respectively. The measurements were performed using the electron-ion merged-beams technique at a heavy-ion storage ring. Electron-ion collision energies ranged from 0 to 50 eV for Si9+ and from 0 to 2000 eV for Si10+, thus, extending previous measurements for Si10+ [Orban et al. 2010, Astrophys. J. 721, 1603] to much higher energies. Experimentally derived rate coefficients for the recombination of Si9+ and Si10+ ions in a plasma are presented along with simple parameterizations. These rate coefficients are useful for the modeling of the charge balance of silicon in photoionized plasmas (Si9+ and Si10+) and in collisionally ionized plasmas (Si10+ only). In the corresponding temperature ranges, the experimentally derived rate coefficients agree with the latest corresponding theoretical results within the experimental uncertainties., Comment: 17 pages, 7 figures, 3 tables, 66 references, submitted to the J. Phys. B special issue on atomic and molecular data for astrophysicists

Published
2015
Full Text
View/download PDF

5. Storage Ring Cross Section Measurements for Electron Impact Ionization of Fe 7+

Author

Hahn, M., Becker, A., Bernhardt, D., Grieser, M., Krantz, C., Lestinsky, M., Müller, A., Novotný, O., Repnow, R., Schippers, S., Spruck, K., Wolf, A., and Savin, D. W.

Subjects
Physics - Atomic Physics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We have measured electron impact ionization (EII) for Fe 7+ from the ionization threshold up to 1200 eV. The measurements were performed using the TSR heavy ion storage ring. The ions were stored long enough prior to measurement to remove most metastables, resulting in a beam of 94% ground state ions. Comparing with the previously recommended atomic data, we find that the Arnaud & Raymond (1992) cross section is up to about 40\% larger than our measurement, with the largest discrepancies below about 400~eV. The cross section of Dere (2007) agrees to within 10%, which is about the magnitude of the experimental uncertainties. The remaining discrepancies between measurement and the most recent theory are likely due to shortcomings in the theoretical treatment of the excitation-autoionization contribution., Comment: Submitted to the Astrophysical Journal

Published
2015
Full Text
View/download PDF

6. Recombination of W18+ ions with electrons: Absolute rate coefficients from a storage-ring experiment and from theoretical calculations

Author

Spruck, K., Badnell, N. R., Krantz, C., Novotný, O., Becker, A., Bernhardt, D., Grieser, M., Hahn, M., Repnow, R., Savin, D. W., Wolf, A., Müller, A., and Schippers, S.

Subjects
Physics - Atomic Physics, Physics - Plasma Physics
Abstract

We present new experimentally measured and theoretically calculated rate coefficients for the electron-ion recombination of W$^{18+}$([Kr] $4d^{10}$ $4f^{10}$) forming W$^{17+}$. At low electron-ion collision energies, the merged-beam rate coefficient is dominated by strong, mutually overlapping, recombination resonances. In the temperature range where the fractional abundance of W$^{18+}$ is expected to peak in a fusion plasma, the experimentally derived Maxwellian recombination rate coefficient is 5 to 10 times larger than that which is currently recommended for plasma modeling. The complexity of the atomic structure of the open-$4f$-system under study makes the theoretical calculations extremely demanding. Nevertheless, the results of new Breit-Wigner partitioned dielectronic recombination calculations agree reasonably well with the experimental findings. This also gives confidence in the ability of the theory to generate sufficiently accurate atomic data for the plasma modeling of other complex ions., Comment: 11 pages, 4 figures, 2 tables, 40 references, accepted for publication in Physical Review A

Published
2014
Full Text
View/download PDF

7. Absolute rate coefficients for photorecombination and electron-impact ionization of magnesium-like iron ions from measurements at a heavy-ion storage ring

Author

Bernhardt, D., Becker, A., Grieser, M., Hahn, M., Krantz, C., Lestinsky, M., Novotný, O., Repnow, R., Savin, D. W., Spruck, K., Wolf, A., Müller, A., and Schippers, S.

Subjects
Physics - Atomic Physics
Abstract

Rate coefficients for photorecombination (PR) and cross sections for electron-impact ionization (EII) of Fe$^{14+}$ forming Fe$^{13+}$ and Fe$^{15+}$, respectively, have been measured by employing the electron-ion merged-beams technique at a heavy-ion storage ring. Rate coefficients for PR and EII of Fe$^{14+}$ ions in a plasma are derived from the experimental measurements. Simple parametrizations of the experimentally derived plasma rate coefficients are provided for use in the modeling of photoionized and collisionally ionized plasmas. In the temperature ranges where Fe$^{14+}$ is expected to form in such plasmas the latest theoretical rate coefficients of Altun et al. [Astron. Astrophys. 474, 1051 (2007)] for PR and of Dere [Astron. Astrophys. 466, 771 (2007)] for EII agree with the experimental results to within the experimental uncertainties. Common features in the PR and EII resonance structures are identified and discussed., Comment: 12 pages, 6 figures, 3 tables, submitted for publication to Physical Review A

Published
2014
Full Text
View/download PDF

8. Dissociative recombination measurements of HCl+ using an ion storage ring

Author

Novotný, O., Becker, A., Buhr, H., Domesle, C., Geppert, W., Grieser, M., Krantz, C., Kreckel, H., Repnow, R., Schwalm, D., Spruck, K., Stützel, J., Yang, B., Wolf, A., and Savin, D. W.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Atomic Physics
Abstract

We have measured dissociative recombination of HCl+ with electrons using a merged beams configuration at the heavy-ion storage ring TSR located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We present the measured absolute merged beams recombination rate coefficient for collision energies from 0 to 4.5 eV. We have also developed a new method for deriving the cross section from the measurements. Our approach does not suffer from approximations made by previously used methods. The cross section was transformed to a plasma rate coefficient for the electron temperature range from T=10 to 5000 K. We show that the previously used HCl+ DR data underestimate the plasma rate coefficient by a factor of 1.5 at T=10 K and overestimate it by a factor of 3.0 at T=300 K. We also find that the new data may partly explain existing discrepancies between observed abundances of chlorine-bearing molecules and their astrochemical models., Comment: Accepted for publication in ApJ (July 7, 2013)

Published
2013
Full Text
View/download PDF

9. Storage Ring Cross Section Measurements for Electron Impact Single and Double Ionization of Fe^13+ and Single Ionization of Fe^16+ and Fe^17+

Author

Hahn, M., Becker, A., Bernhardt, D., Grieser, M., Krantz, C., Lestinsky, M., Müller, A., Novotný, O., Repnow, R., Schippers, S., Spruck, K., Wolf, A., and Savin, D. W.

Subjects
Physics - Atomic Physics
Abstract

We report measurements of electron impact ionization (EII) for Fe^13+, Fe^16+, and Fe^17+ over collision energies from below threshold to above 3000 eV. The ions were recirculated using an ion storage ring. Data were collected after a sufficiently long time that essentially all the ions had relaxed radiatively to their ground state before data were collected. For single ionization of $\fethirteen$ we find that previous single pass experiments are more than 40% larger than our results. Compared to our work, the theoretical cross section recommended by Arnaud & Raymond (1992) is more than 30% larger, while that of Dere (2007) is about 20% greater. Much of the discrepancy with Dere (2007) is due to the theory overestimating the contribution of excitation-autoionization via n=2 excitations. Double ionization of Fe^13+ is dominated by direct ionization of an inner shell electron accompanied by autoionization of a second electron. Our results for single ionization of Fe^16+ and Fe^17+ agree with theoretical calculations to within the experimental uncertainties., Comment: Accepted for the Astrophysical Journal

Published
2013
Full Text
View/download PDF

10. Electron-impact ionisation of $W^{q+}$ ions with 1 ⩽ q ⩽ 19

Author

Schury, Daniel, Becker, A., Schippers, S., Müller, A., Borovik, A., Ebinger, B., Gharaibeh, M. F., Hellhund, J., Huber, K., Rausch, J., Spruck, K., and Jin, F.

Subjects
ddc:530
Abstract

31st International Conference on Photonic, Electronic and Atomic Collisions, ICPEAC XXXI, Deauville, France, 23 Jul 2019 - 30 Jul 2019; Journal of physics / Conference series 1412, 152011 (2020). doi:10.1088/1742-6596/1412/15/152011, Published by IOP Publ., Bristol

Published
2020
Full Text
View/download PDF

11. Electron-impact ionisation of Wq+ ions with 1 ⩽ q ⩽ 19

Author

Schury, D, primary, Becker, A, additional, Borovik, A, additional, Ebinger, B, additional, Gharaibeh, M F, additional, Hellhund, J, additional, Huber, K, additional, Rausch, J, additional, Spruck, K, additional, Jin, F, additional, Schippers, S, additional, and Müller, A, additional

Published
2020
Full Text
View/download PDF

13. Electron-impact single ionisation of Wq+ions: experiment and theory for 11 ≤ q ≤ 18.

Author

Schury, D, Jr, A Borovik, Ebinger, B, Jin, F, Spruck, K, Müller, A, and Schippers, S

Subjects
ELECTRON-ion collisions, TUNGSTEN
Abstract

Absolute cross sections for electron-impact single ionisation (EISI) of multiply charged tungsten ions (Wq+) with charge states in the range in the electron–ion collision energy ranges from below the respective ionisation thresholds up to 1000 eV were measured employing the electron–ion crossed-beams method. In order to extend the results to higher energies, cross section calculations were performed using the subconfiguration-averaged distorted-wave (SCADW) method for electron–ion collision energies up to 150 keV. From the combined experimental and scaled theoretical cross sections rate coefficients were derived which are compared with the ones contained in the ADAS database and that are based on previous configuration-averaged distorted wave (CADW) calculations of Loch et al (2005 Phys. Rev. A 72 052716). Significant discrepancies were found at the temperatures where the ions investigated here are expected to form in collisionally ionised plasmas. These discrepancies are attributed to the limitations of the CADW approach and also the more detailed SCADW treatment which do not allow for a sufficiently accurate description of the EISI cross sections particularly at the ionisation thresholds. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

14. Recombination of W19+ ions with electrons : absolute rate coefficients from a storage-ring experiment and from theoretical calculations

Author

Badnell, N. R., Spruck, K., Krantz, C., Novotny, Oldrich, Becker, A., Bernhardt, D., Grieser, M., Hahn, Michael, Repnow, R., Savin, Daniel Wolf, Wolf, A., Muller, A., and Schippers, S.

Subjects
Storage rings, Tungsten ions, Electron-ion collisions, QC, Electron impact ionization
Abstract

Experimentally measured and theoretically calculated rate coefficients for the recombination of W 19 + ( [ Kr ] 4 d 10 4 f 9 ) ions with free electrons (forming W 18 + ) are presented. At low electron-ion collision energies, the merged-beam rate coefficient is dominated by strong, mutually overlapping, recombination resonances as already found previously for the neighboring charge-state ions W 18 + and W 20 + . In the temperature range where W 19 + is expected to form in a collisionally ionized plasma, the experimentally derived recombination rate coefficient deviates by up to a factor of about 20 from the theoretical rate coefficient obtained from the Atomic Data and Analysis Structure database. The present calculations, which employ a Breit–Wigner redistributive partitioning of autoionizing widths for dielectronic recombination via multi-electron resonances, reproduce the experimental findings over the entire temperature range.Experimentally measured and theoretically calculated rate coefficients for the recombination of W 19 + ( [ Kr ] 4 d 10 4 f 9 ) ions with free electrons (forming W 18 + ) are presented. At low electron-ion collision energies, the merged-beam rate coefficient is dominated by strong, mutually overlapping, recombination resonances as already found previously for the neighboring charge-state ions W 18 + and W 20 + . In the temperature range where W 19 + is expected to form in a collisionally ionized plasma, the experimentally derived recombination rate coefficient deviates by up to a factor of about 20 from the theoretical rate coefficient obtained from the Atomic Data and Analysis Structure database. The present calculations, which employ a Breit–Wigner redistributive partitioning of autoionizing widths for dielectronic recombination via multi-electron resonances, reproduce the experimental findings over the entire temperature range.

Published
2016

15. Storage Ring Cross Section Measurements for Electron Impact Ionization of Fe8+

Author

Hahn, Michael, Becker, A., Bernhardt, D., Grieser, M., Krantz, C., Lestinsky, M., Muller, A., Novotny, Oldrich, Pindzola, M. S., Repnow, R., Schippers, S., Spruck, K., Wolf, A., and Savin, Daniel Wolf

Subjects
Storage rings, Iron ions, Physics::Atomic Physics, Astrophysics, Electron impact ionization
Abstract

We have measured electron impact ionization (EII) for Fe8+ forming Fe9+ from below the ionization threshold to 1200 eV. These measurements were carried out at the TSR heavy ion storage ring. The objective of using a storage ring is to store the ion beam initially so that metastable levels decay, thereby allowing for measurements on a well-defined ground-level ion beam. In this case, however, some metastable levels were too long lived to be removed. We discuss several methods for quantifying the metastable fraction, which we estimate to be ∼30%– 40%. Although metastables remain problematic, the present storage ring work improves upon other experimental geometries by limiting the metastable contamination to only a few long-lived excited levels. We discuss some future prospects for obtaining improved measurements of Fe8+ and other ions with long-lived metastable levels.

Published
2016
Full Text
View/download PDF

16. Radiative Rotational Lifetimes and State-Resolved Relative Detachment Cross Sections from Photodetachment Thermometry of Molecular Anions in a Cryogenic Storage Ring

Author

Meyer, C., primary, Becker, A., additional, Blaum, K., additional, Breitenfeldt, C., additional, George, S., additional, Göck, J., additional, Grieser, M., additional, Grussie, F., additional, Guerin, E. A., additional, von Hahn, R., additional, Herwig, P., additional, Krantz, C., additional, Kreckel, H., additional, Lion, J., additional, Lohmann, S., additional, Mishra, P. M., additional, Novotný, O., additional, O’Connor, A. P., additional, Repnow, R., additional, Saurabh, S., additional, Schwalm, D., additional, Schweikhard, L., additional, Spruck, K., additional, Sunil Kumar, S., additional, Vogel, S., additional, and Wolf, A., additional

Published
2017
Full Text
View/download PDF

17. Photorecombination of berylliumlike and boronlike silicon ions

Author

Bernhardt, D., primary, Becker, A., additional, Brandau, C., additional, Grieser, M., additional, Hahn, M., additional, Krantz, C., additional, Lestinsky, M., additional, Novotný, O., additional, Repnow, R., additional, Savin, D. W., additional, Spruck, K., additional, Wolf, A., additional, Müller, A., additional, and Schippers, S., additional

Published
2017
Full Text
View/download PDF

19. The cryogenic storage ring CSR

Author

UCL - SST/IMCN/NAPS - Nanoscopic Physics, von Hahn, R., Becker, A., Berg, F., Blaum, K., Breitenfeldt, C., Fadil, H., Fellenberger, F., Froese, M., George, S., Göck, J., Grieser, M., Grussie, F., Guerin, E. A., Heber, O., Herwig, P., Karthein, J., Krantz, C., Kreckel, H., Lange, M., Laux, F., Lohmann, S., Menk, S., Meyer, C., Mishra, P. M., Novotný, O., O’Connor, A. P., Orlov, D. A., Rappaport, M. L., Repnow, R., Saurabh, S., Schippers, S., Schröter, C. D., Schwalm, D., Schweikhard, L., Sieber, T., Shornikov, A., Spruck, K., Sunil Kumar, S., Ullrich, J., Urbain, Xavier, Vogel, S., Wilhelm, P., Wolf, A., Zajfman, D., UCL - SST/IMCN/NAPS - Nanoscopic Physics, von Hahn, R., Becker, A., Berg, F., Blaum, K., Breitenfeldt, C., Fadil, H., Fellenberger, F., Froese, M., George, S., Göck, J., Grieser, M., Grussie, F., Guerin, E. A., Heber, O., Herwig, P., Karthein, J., Krantz, C., Kreckel, H., Lange, M., Laux, F., Lohmann, S., Menk, S., Meyer, C., Mishra, P. M., Novotný, O., O’Connor, A. P., Orlov, D. A., Rappaport, M. L., Repnow, R., Saurabh, S., Schippers, S., Schröter, C. D., Schwalm, D., Schweikhard, L., Sieber, T., Shornikov, A., Spruck, K., Sunil Kumar, S., Ullrich, J., Urbain, Xavier, Vogel, S., Wilhelm, P., Wolf, A., and Zajfman, D.

Abstract

An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm−3 is derived, equivalent to a room-temperature pressure below 10−14 mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal uantum states with merged and crossed photon and particle beams.

Published
2016

20. Recombination of W 18 + ions with electrons: Absolute rate coefficients from a storage-ring experiment and from theoretical calculations

Author

Spruck, K., Badnell, N. R., Krantz, C., Novotny, Oldrich, Becker, A., Bernhardt, D., Grieser, M., Hahn, Michael, Repnow, R., Savin, Daniel Wolf, Wolf, A., Muller, A., and Schippers, S.

Subjects
Storage rings, Physics::Plasma Physics, Ion recombination, Astrophysics, Tungsten ions, Electron impact ionization
Abstract

We present experimentally measured and theoretically calculated rate coefficients for the electron-ion recombination of W 18 + ( [ Kr ] 4 d 10 4 f 10 ) forming W 17 + . At low electron-ion collision energies, the merged-beam rate coefficient is dominated by strong, mutually overlapping recombination resonances. In the temperature range where the fractional abundance of W 18 + is expected to peak in a fusion plasma, the experimentally derived Maxwellian recombination rate coefficient is 5 to 10 times larger than that which is currently recommended for plasma modeling. The complexity of the atomic structure of the open- 4 f system under study makes the theoretical calculations extremely demanding. Nevertheless, the results of the present Breit-Wigner partitioned dielectronic recombination calculations agree reasonably well with the experimental findings. This also gives confidence in the ability of the theory to generate sufficiently accurate atomic data for the plasma modeling of other complex ions.

Published
2014
Full Text
View/download PDF

22. The cryogenic storage ring CSR

Author

von Hahn, R., primary, Becker, A., additional, Berg, F., additional, Blaum, K., additional, Breitenfeldt, C., additional, Fadil, H., additional, Fellenberger, F., additional, Froese, M., additional, George, S., additional, Göck, J., additional, Grieser, M., additional, Grussie, F., additional, Guerin, E. A., additional, Heber, O., additional, Herwig, P., additional, Karthein, J., additional, Krantz, C., additional, Kreckel, H., additional, Lange, M., additional, Laux, F., additional, Lohmann, S., additional, Menk, S., additional, Meyer, C., additional, Mishra, P. M., additional, Novotný, O., additional, O’Connor, A. P., additional, Orlov, D. A., additional, Rappaport, M. L., additional, Repnow, R., additional, Saurabh, S., additional, Schippers, S., additional, Schröter, C. D., additional, Schwalm, D., additional, Schweikhard, L., additional, Sieber, T., additional, Shornikov, A., additional, Spruck, K., additional, Sunil Kumar, S., additional, Ullrich, J., additional, Urbain, X., additional, Vogel, S., additional, Wilhelm, P., additional, Wolf, A., additional, and Zajfman, D., additional

Published
2016
Full Text
View/download PDF

23. Recombination ofW19+ions with electrons: Absolute rate coefficients from a storage-ring experiment and from theoretical calculations

Author

Badnell, N. R., primary, Spruck, K., additional, Krantz, C., additional, Novotný, O., additional, Becker, A., additional, Bernhardt, D., additional, Grieser, M., additional, Hahn, M., additional, Repnow, R., additional, Savin, D. W., additional, Wolf, A., additional, Müller, A., additional, and Schippers, S., additional

Published
2016
Full Text
View/download PDF

26. Photodissociation of an Internally Cold Beam ofCH+Ions in a Cryogenic Storage Ring

Author

O’Connor, A. P., primary, Becker, A., additional, Blaum, K., additional, Breitenfeldt, C., additional, George, S., additional, Göck, J., additional, Grieser, M., additional, Grussie, F., additional, Guerin, E. A., additional, von Hahn, R., additional, Hechtfischer, U., additional, Herwig, P., additional, Karthein, J., additional, Krantz, C., additional, Kreckel, H., additional, Lohmann, S., additional, Meyer, C., additional, Mishra, P. M., additional, Novotný, O., additional, Repnow, R., additional, Saurabh, S., additional, Schwalm, D., additional, Spruck, K., additional, Sunil Kumar, S., additional, Vogel, S., additional, and Wolf, A., additional

Published
2016
Full Text
View/download PDF

27. The cryogenic storage ring CSR for collision experiments with state-controlled and phase-space cooled molecular ion beams

Author

UCL - SST/IMCN/NAPS - Nanoscopic Physics, Becker, A, Blaum, K, Breitenfeldt, C, Fellenberger, F, George, S, Göck, J, Grieser, M, Grussie, F, von Hahn, R, Herwig, P, Karthein, J, Krantz, C, Kreckel, H, Kumar, S, Lange, M, Lohmann, S, Meyer, C, Mishra, P M, Novotný, O, O'Connor, A, Repnow, R, Schippers, S, Schröter, C D, Spruck, K, Schwalm, D, Schweikard, L, Urbain, Xavier, Vogel, S, Wolf, A, UCL - SST/IMCN/NAPS - Nanoscopic Physics, Becker, A, Blaum, K, Breitenfeldt, C, Fellenberger, F, George, S, Göck, J, Grieser, M, Grussie, F, von Hahn, R, Herwig, P, Karthein, J, Krantz, C, Kreckel, H, Kumar, S, Lange, M, Lohmann, S, Meyer, C, Mishra, P M, Novotný, O, O'Connor, A, Repnow, R, Schippers, S, Schröter, C D, Spruck, K, Schwalm, D, Schweikard, L, Urbain, Xavier, Vogel, S, and Wolf, A

Abstract

The cryogenic storage ring (CSR) for positive and negative atomic, molecular and cluster ions is starting operation at the Max Planck Institute for Nuclear Physics in Heidelberg.

Published
2015

28. Storage Ring Cross-Section Measurements for Electron Impact Single and Double Ionization of Fe9 + and Single Ionization of Fe10 +

Author

Hahn, Michael, Becker, A., Grieser, M., Krantz, C., Lestinsky, M., Muller, A., Novotny, Oldrich, Repnow, R., Schippers, S., Spruck, K., Wolf, A., and Savin, Daniel Wolf

Subjects
Plasma (Ionized gases), Physics, Astrophysics, Microphysics
Abstract

We have measured electron impact ionization from the ground state of Fe9 + and Fe10 + over the relative electron-ion collision energy ranges 200-1900 eV and 250-1800 eV, respectively. The ions were confined in an ion storage ring long enough for essentially all metastable levels to radiatively relax to the ground state. For single ionization, we find a number of discrepancies between the existing theoretical cross sections and our results. The calculations appear to neglect some excitation-autoionization (EA) channels, particularly from n = 3 to n' excitations, which are important near threshold, and those from n = 2 → 3 excitations, which contribute at about 650 eV. Conversely, at higher energies the calculations appear to overestimate the importance of EA channels due to excitation into levels where n ≥ 4. The resulting experimental rate coefficients agree with the most recent theory for Fe9 + to within 16% and for Fe10 + to within 19% at temperatures where these ions are predicted to form in collisional ionization equilibrium. We have also measured double ionization of Fe9 + forming Fe11 + in the energy range 450-3000 eV and found that although there is an appreciable cross section for direct double ionization, the dominant mechanism appears to be through direct ionization of an inner shell electron producing an excited state that subsequently stabilizes through autoionization.

Published
2012
Full Text
View/download PDF

31. ERRATUM: “DISSOCIATIVE RECOMBINATION MEASUREMENTS OF HCl+ USING AN ION STORAGE RING” (2013, ApJ, 777, 54)

Author

Novotný, O., primary, Becker, A., additional, Buhr, H., additional, Domesle, C., additional, Geppert, W., additional, Grieser, M., additional, Krantz, C., additional, Kreckel, H., additional, Repnow, R., additional, Schwalm, D., additional, Spruck, K., additional, Stützel, J., additional, Yang, B., additional, Wolf, A., additional, and Savin, D. W., additional

Published
2015
Full Text
View/download PDF

32. Electron-ion recombination of the open-4f-shell ion W19+

Author

Badnell, N R, primary, Spruck, K, additional, Krantz, C, additional, Novotný, O, additional, Becker, A, additional, Bernhardt, D, additional, Grieser, M, additional, Hahn, M, additional, Repnow, R, additional, Savin, D W, additional, Wolf, A, additional, Müller, A, additional, and Schippers, S, additional

Published
2015
Full Text
View/download PDF

33. The cryogenic storage ring CSR for collision experiments with state-controlled and phase-space cooled molecular ion beams

Author

Becker, A, primary, Blaum, K, additional, Breitenfeldt, C, additional, Fellenberger, F, additional, George, S, additional, Göck, J, additional, Grieser, M, additional, Grussie, F, additional, von Hahn, R, additional, Herwig, P, additional, Karthein, J, additional, Krantz, C, additional, Kreckel, H, additional, Kumar, S, additional, Lange, M, additional, Lohmann, S, additional, Meyer, C, additional, Mishra, P M, additional, Novotný, O, additional, O'Connor, A, additional, Repnow, R, additional, Schippers, S, additional, Schröter, C D, additional, Spruck, K, additional, Schwalm, D, additional, Schweikard, L, additional, Urbain, X, additional, Vogel, S, additional, and Wolf, A, additional

Published
2015
Full Text
View/download PDF

35. Electron-impact ionization of tungsten ions

Author

Borovik, A, primary, Schury, D, additional, Ebinger, B, additional, Spruck, K, additional, Becker, A, additional, Gharaibeh, M F, additional, Rausch, J, additional, Schippers, S, additional, and Müller, A, additional

Published
2015
Full Text
View/download PDF

36. ERRATUM: “DISSOCIATIVE RECOMBINATION MEASUREMENTS OF HCl+ USING AN ION STORAGE RING” (2013, ApJ, 777, 54)

Author

Novotný, O., primary, Becker, A., additional, Buhr, H., additional, Domesle, C., additional, Geppert, W., additional, Grieser, M., additional, Krantz, C., additional, Kreckel, H., additional, Repnow, R., additional, Schwalm, D., additional, Spruck, K., additional, Stützel, J., additional, Yang, B., additional, Wolf, A., additional, and Savin, D. W., additional

Published
2014
Full Text
View/download PDF

37. Recombination ofW18+ions with electrons: Absolute rate coefficients from a storage-ring experiment and from theoretical calculations

Author

Spruck, K., primary, Badnell, N. R., additional, Krantz, C., additional, Novotný, O., additional, Becker, A., additional, Bernhardt, D., additional, Grieser, M., additional, Hahn, M., additional, Repnow, R., additional, Savin, D. W., additional, Wolf, A., additional, Müller, A., additional, and Schippers, S., additional

Published
2014
Full Text
View/download PDF

38. Absolute rate coefficients for photorecombination and electron-impact ionization of magnesiumlike iron ions from measurements at a heavy-ion storage ring

Author

Bernhardt, D., primary, Becker, A., additional, Grieser, M., additional, Hahn, M., additional, Krantz, C., additional, Lestinsky, M., additional, Novotný, O., additional, Repnow, R., additional, Savin, D. W., additional, Spruck, K., additional, Wolf, A., additional, Müller, A., additional, and Schippers, S., additional

Published
2014
Full Text
View/download PDF

42. Recombination of open-4f-shell W18+ ions with free electrons

Author

Spruck, K, primary, Badnell, N R, additional, Krantz, C, additional, Becker, A, additional, Bernhardt, D, additional, Grieser, M, additional, Hahn, M, additional, Novotný, O, additional, Repnow, R, additional, Savin, D W, additional, Wolf, A, additional, Müller, A, additional, and Schippers, S, additional

Published
2014
Full Text
View/download PDF

44. DISSOCIATIVE RECOMBINATION MEASUREMENTS OF HCl+ USING AN ION STORAGE RING

Author

Novotný, O., primary, Becker, A., additional, Buhr, H., additional, Domesle, C., additional, Geppert, W., additional, Grieser, M., additional, Krantz, C., additional, Kreckel, H., additional, Repnow, R., additional, Schwalm, D., additional, Spruck, K., additional, Stützel, J., additional, Yang, B., additional, Wolf, A., additional, and Savin, D. W., additional

Published
2013
Full Text
View/download PDF

45. STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT SINGLE AND DOUBLE IONIZATION OF Fe13 +AND SINGLE IONIZATION OF Fe16 +AND Fe17 +

Author

Hahn, M., primary, Becker, A., additional, Bernhardt, D., additional, Grieser, M., additional, Krantz, C., additional, Lestinsky, M., additional, Müller, A., additional, Novotný, O., additional, Repnow, R., additional, Schippers, S., additional, Spruck, K., additional, Wolf, A., additional, and Savin, D. W., additional

Published
2013
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results