Atomic charge exchange between fast helium ions and targets from carbon to bismuth at β=0.36

Dennis, Kadeem; Akimune, Hideo; Berg, G.P.A.; Chang, S.; Davis, Brian F.; Fujiwara, M̄.; Harakeh, Mohsen; Jänecke, J.; Liu, J.; Pham, Kevin; Roberts, D. A.; Stephenson, E. J.

doi:10.1103/physreva.50.3992

Cited by 19 publications

(9 citation statements)

References 24 publications

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“…The experimental results are compared with the theoretical calculations mentioned above and are an extension to higher beam energies of the work by Dennis et al [10]. We also compare results with the predictions of the codes CHARGE and GLOBAL [12] (implemented in the code LISE++ [13]), to demonstrate the need for improved estimates of charge-exchange cross sections for fast radioactive ion beam experiments.…”

Section: Introductionmentioning

confidence: 97%

“…[10]. Classical approximations for the stripping cross section of low, medium, and high-Z T targets were derived by Bohr [6].…”

Section: Theoretical Cross-section Estimatesmentioning

confidence: 99%

“…It was previously found that at energies up to 200 MeV [9,10] a combination of the descriptions by Bohr for medium-Z targets and Gillespie reproduced the data if the latter approach was used for low-Z nuclei. We have found that at 420 MeV, the Gillespie approximation represents the data over the full target range.…”

mentioning

confidence: 99%

“…A semi-phenomenological approach is often used, based on the works of Allison [4], Betz [5], Bohr [6], Gillespie [7] and Nikolaev [8] and tested experimentally by Katayama et al [9], Dennis et al [10] and Gójska et al [11]. This approach takes into account the balance between electron stripping and capture contributions, and the results of the calculations are in good agreement with data obtained over the energy range tested thus far (E( 3 He) = 67.9 MeV, 99.2 MeV, 130.2 MeV [9], and 200 MeV [10]). …”

Section: Introductionmentioning

confidence: 99%

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Atomic charge exchange between semi-relativistic ( v/c = 0.49 ) helium ions and targets from carbon to lead.

Meharchand¹,

Zegers²

2009

Proceedings of 10th Symposium on Nuclei in the Cosmos — PoS(NIC X)

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In ( 3 He,t) nuclear charge-exchange reactions, 3 He + charge states are produced as a result of atomic charge-exchange between 3 He ++ ions and atoms in the target. In equilibrium, the atomic charge-exchange process consists of both electron ionization (stripping), and electron capture, which can proceed through Radiative Electron Capture (REC) or Non-Radiative Electron Capture (NREC). Unfortunately, a complete description of the atomic charge-exchange process is lacking. As a result, a largely phenomenological approach has been used, which has not been tested for high beam energies. In this work, ratios of equilibrium charge-state yields for singly to doubly ionized 3 He ions were measured using the Grand Raiden Spectrometer at the Research Center for Nuclear Physics (RCNP). A semi-phenomenological approach used when calculating atomic electron capture and stripping cross sections is successful in describing the data for beam energies of E( 3 He) = 420 MeV. 10th Symposium on Nuclei in the Cosmos

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Section: Introductionmentioning

confidence: 97%

“…[10]. Classical approximations for the stripping cross section of low, medium, and high-Z T targets were derived by Bohr [6].…”

Section: Theoretical Cross-section Estimatesmentioning

confidence: 99%

mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Atomic charge exchange between semi-relativistic ( v/c = 0.49 ) helium ions and targets from carbon to lead.

Meharchand¹,

Zegers²

2009

Proceedings of 10th Symposium on Nuclei in the Cosmos — PoS(NIC X)

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“…Very good identification with the focal-plane detector of the spectrograph was required to overcome the huge background due to the 3 He ++ → 3 He + atomic chargeexchange process [12], since the Q-values for the ( 3 He,t) reactions on 176 Yb leading to the lowest 1 + states in the residual nuclei is ≤ 0.3 MeV. For this purpose, we added a plastic scintillation counter with a thickness of 1 mm in front of the two ∆E counters of 10 mm thickness for improved particle identification.…”

mentioning

confidence: 99%

Gamow-Teller Strengths of the Inverse Beta TransitionY176b→L176<

et al. 2000

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Discrete Gamow-Teller (GT) transitions, 176 Yb→ 176 Lu at low excitation energies have been measured via the ( 3 He,t) reaction at 450 MeV and at 0 • . For 176 Yb, two low-lying states are observed, setting low thresholds Q(ν)=301 and 445 keV for neutrino (ν) capture. Capture rates estimated from the measured GT strengths, the simple two-state excitation structure, and the low Q(ν) in Yb-Lu indicate that Yb-based ν-detectors are well suited for a direct measurement of the complete sub-MeV solar electron-neutrino (νe) spectrum (including pp neutrinos) where definitive effects of flavor conversion are expected. The conceivable conversion mechanisms produce ν e flux deficits that are energy dependent (typically strongest at low energies) and result in large deficits of either the pp and/or the 7 Be ν e fluxes, the two dominant features of the sub-MeV spectrum. A deficit in the model-independent pp-neutrino flux and/or a 7 Be ν e flux measurably smaller than the total all-flavor flux (expected from the Borexino experiment [6] in particular), would provide the most direct proof of flavor conversion. A real-time measurement of the complete ν e spectrum from the sun and source-specific fluxes is, thus, of central interest for solving the solar-ν problem. Such data are not available yet since the operating low-energy Ga detectors yield only the integral signal rate above a threshold, not the fluxes from specific solar ν sources.Recently, Raghavan [7] suggested a possible way to construct a low-threshold, flavor-specific scheme for realtime detection of solar neutrinos via neutrino captures based on the charged current mediated GamowTeller (GT) transitions ν e + 176 Yb→e − + 176 Lu * and ν e + 160 Gd→e − + 160 Tb * . The basic idea is to identify absorption events of pp and 7 Be neutrinos by a delayed coincidence between a prompt e − event and a cascade γ-ray via isomeric states in 176 Lu or 160 Tb. The coincidence tag (with time gates ≤10 −7 s) allows suppression of background events by a factor of 10 7 . For the first time, this scheme offers the tools for practical real-time spectroscopy even of pp-neutrinos despite the formidable backgrounds that have precluded low-energy ν spectroscopy so far. Feasibility studies are in progress for constructing such a solar ν detector LENS (LowEnergy Neutrino Spectroscopy) [8].The basic input data for designing LENS are the cross sections of the GT transitions in Yb and Gd for which the weak matrix elements B(GT) must be determined for each of the low-lying 1 + states excited by neutrino cap-1

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Radiative and non-radiative electron capture from carbon atoms by relativistic helium ions

Gójska¹,

Chmielewska²,

Rymuza³

et al.

The 2nd International Conference on Nuclear Physics in Astrophysics

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Abstract. Interaction of radiation with helium atoms and/or ions is of interest in various astrophysical applications. The reverse reactions of fast 150 MeV/amu 3 He ++ ions with solid C targets have been studied at the isochronous cyclotron of the RCNP in Osaka. The singly ionized helium ions resulting from capture of the target electrons to the projectile were observed with the use of large magnetic spectrograph, Grand Raiden, set at θ = 0• with respect to the beam. The yield ratios of singly-to-doubly ionized helium ions emerging from thin carbon foils, He + /He ++ , have been measured as a function of the foil thickness. Extrapolating the results to zero target thickness permits to determine the cross section values separately for electron stripping from 3 He + ions and for electron capture to 3 He ++ ions. The radiative and nonradiative contributions to the capture cross section were determined in a separate experiment in which the 84 keV (C.M.) photons were observed in coincidence with the He + ejectiles. The results are compared with theoretical predictions. Need for improved calculations is noted for all the three processes involved, i.e. for the radiative and non radiative electron capture as well as for the electron stripping.PACS. 25.40.Lw Radiative capture -34.70.+e Charge transfer

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Atomic charge exchange between fast helium ions and targets from carbon to bismuth at β=0.36

Cited by 19 publications

References 24 publications

Atomic charge exchange between semi-relativistic ( v/c = 0.49 ) helium ions and targets from carbon to lead.

Atomic charge exchange between semi-relativistic ( v/c = 0.49 ) helium ions and targets from carbon to lead.

Gamow-Teller Strengths of the Inverse Beta TransitionY176b→L176<

Radiative and non-radiative electron capture from carbon atoms by relativistic helium ions

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