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Siddiki MAKA, Nrishimhamurty M, Kumar K, Mukherjee J, Tribedi LC, Khan A, Misra D. Development of a cold target recoil ion momentum spectrometer and a projectile charge state analyzer setup to study electron transfer processes in highly charged ion-atom/molecule collisions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113313. [PMID: 36461444 DOI: 10.1063/5.0100395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
We report the development and performance of a cold target recoil ion momentum spectrometer (COLTRIMS) setup at TIFR, which is built to study various atomic and molecular processes involving the interaction of slow, highly charged ions from an electron cyclotron resonance based ion accelerator. We give a detailed description of the experimental setup, as well as report some initial results on the electron-capture process in collisions of Ar8+ ions with helium and carbon monoxide targets. Here, we present the longitudinal momentum transfer and the sub-shell resolved Q-value spectrum in the case of 2, 4, and 6 keV/u Ar8+ beams in collision with helium. A longitudinal momentum resolution of 0.27 a.u. is achieved in the present system. We also report the state-selective scattering angle distributions for all the collision systems under investigation. We further discuss the fragmentation of the CO2+ molecular ions for different electron capture channels for the 5 keV/u Ar8+ beam. The combination of the COLTRIMS, along with the beam cleaner, the electrostatic deflectors, and the charge state analyzer, is shown to have certain advantages.
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Affiliation(s)
- Md Abul Kalam Azad Siddiki
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - M Nrishimhamurty
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - Kamal Kumar
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - Jibak Mukherjee
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - Lokesh C Tribedi
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - Arnab Khan
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - Deepankar Misra
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
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Fischer D, Globig D, Goullon J, Grieser M, Hubele R, de Jesus VLB, Kelkar A, LaForge A, Lindenblatt H, Misra D, Najjari B, Schneider K, Schulz M, Sell M, Wang X. Ion-lithium collision dynamics studied with a laser-cooled in-ring target. PHYSICAL REVIEW LETTERS 2012; 109:113202. [PMID: 23005625 DOI: 10.1103/physrevlett.109.113202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Indexed: 06/01/2023]
Abstract
We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the 'MOTReMi,' is a combination of a magneto-optical trap (MOT) and a reaction microscope (ReMi). Operated in an ion-storage ring, the new setup enables us to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In the inaugural experiment on collisions with 1.5 MeV/amu O(8+)-Li the pure ionization of the valence electron as well as the ionization-excitation of the lithium target was investigated.
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Affiliation(s)
- D Fischer
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
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Schulz M, Wang X, Gundmundsson M, Schneider K, Kelkar A, Voitkiv AB, Najjari B, Schöffler M, Schmidt LPH, Dörner R, Ullrich J, Moshammer R, Fischer D. Strongly enhanced backward emission of electrons in transfer and ionization. PHYSICAL REVIEW LETTERS 2012; 108:043202. [PMID: 22400839 DOI: 10.1103/physrevlett.108.043202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Indexed: 05/31/2023]
Abstract
We studied three-dimensional angular distributions and longitudinal momentum spectra of electrons ejected in transfer plus ionization (TI), i.e., the ejection of one and the capture of a second target electron, for ion-helium collisions. We observe a pronounced structure strongly focused opposite to the projectile beam direction, which we associate with a new correlated TI mechanism proposed recently. This process contributes significantly to the total cross sections over a broad range of perturbations η, even at η as large as 0.5, where uncorrelated TI mechanisms were thought to be dominant.
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Affiliation(s)
- M Schulz
- Physics Department and LAMOR, Missouri University of Science & Technology, Rolla, Missouri 65409, USA
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Guan X, Bartschat K. Complete breakup of the helium atom by proton and antiproton impact. PHYSICAL REVIEW LETTERS 2009; 103:213201. [PMID: 20366034 DOI: 10.1103/physrevlett.103.213201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Indexed: 05/29/2023]
Abstract
We present a fully ab initio, nonperturbative, time-dependent approach to describe single and double ionization of helium by proton and antiproton impact. The problem is discretized by a flexible finite-element discrete-variable representation on the radial grid. Good agreement with the most recent experimental data for absolute angle-integrated cross sections is obtained for projectile energies between 3 keV and 6 MeV. Also, angle-differential cross sections for two-electron ejection are predicted for a proton impact energy of 6 MeV. The time evaluation of the ionization process is portrayed by displaying the electron density as a function of the projectile location.
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Affiliation(s)
- Xiaoxu Guan
- Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311, USA.
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Dürr M, Dorn A, Ullrich J, Cao SP, Czasch A, Kheifets AS, Götz JR, Briggs JS. (e,3e) on helium at low impact energy: the strongly correlated three-electron continuum. PHYSICAL REVIEW LETTERS 2007; 98:193201. [PMID: 17677618 DOI: 10.1103/physrevlett.98.193201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Indexed: 05/16/2023]
Abstract
Double ionization of the helium atom by slow electron impact (E(0)=106 eV) is studied in a kinematically complete experiment. Because of a low excess energy E(exc)=27 eV above the double ionization threshold, a strongly correlated three-electron continuum is realized. This is demonstrated by measuring and calculating the fully differential cross sections for equal energy sharing of the final-state electrons. While the electron emission is dominated by a strong Coulomb repulsion, also signatures of more complex dynamics of the full four-body system are identified.
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Affiliation(s)
- M Dürr
- Max-Planck-Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
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Dürr M, Dimopoulou C, Najjari B, Dorn A, Ullrich J. Three-dimensional images for electron-impact single ionization of He: complete and comprehensive (e, 2e) benchmark data. PHYSICAL REVIEW LETTERS 2006; 96:243202. [PMID: 16907237 DOI: 10.1103/physrevlett.96.243202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Indexed: 05/11/2023]
Abstract
Comprehensive fully differential cross sections for electron emission into all three spatial dimensions are presented for 1 keV and 102 eV electron-impact single ionization of helium using an advanced reaction microscope. Surprising out-of-plane contributions, traced back to an interference term in a perturbation expansion by comparison with ion-impact data, severely challenge theoretical models that accurately predict coplanar emission. The data represent the ultimate benchmark for recently developed exact theoretical descriptions of the most fundamental three-body quantum problems.
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Affiliation(s)
- M Dürr
- Max-Planck-Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
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