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Author

K. Brand

Bio: K. Brand is an academic researcher from Ruhr University Bochum. The author has contributed to research in topics: Dynamitron & Recoil. The author has an hindex of 8, co-authored 14 publications receiving 348 citations.
Topics: Dynamitron, Recoil, Ion beam, Ion gun, Ion

Papers
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Journal ArticleDOI
TL;DR: In this article, high-current accelerators with well-known beam characteristics and windowless gas target systems of the extended and quasi-point supersonic jet type were used for the measurement of absolute cross sections, angular distributions and excitation functions.

178 citations

Journal ArticleDOI
TL;DR: In this article, the energy calibration of the beam analyzing magnet at the 4 MV Dynamitron tandem accelerator in Bochum has been carried out over a wide magnetic field range (B =24 −124 kG) using the well-known energies of several proton induced resonance reactions.

38 citations

Journal ArticleDOI
K. Brand1
TL;DR: In this article, the cesium beam of a General Ionex 834 sputter source is steered through an off-axis molybdenum cone, reflected by the negative ion extraction electrode and sharply focused on a pill of target material located on the back of the cone.

36 citations

Journal ArticleDOI
TL;DR: In this article, a recoil separator was designed for the measurement of the radiative capture reaction p(7Be, γ)8B. The separator consists of momentum and velocity filters and a ΔE−E detector telescope.
Abstract: A recoil separator in combination with a windowless gas target has been designed for the measurement of the radiative capture reaction p(7Be, γ)8B. The separator consists of momentum and velocity filters and a ΔE−E detector telescope. The setup was tested quantitatively using the p(12C, γ)13N reaction at the effective energy Ecm = 841 keV. Projectile fluxes were measured directly with Faraday cups and indirectly with elastic backscattering into Si detectors, while the 13N recoil flux was measured directly with the ΔE−E telescope. A suppression of the 12C beam particles by a factor 2 × 10−10 was observed when the system was tuned for the recoil 13N's. Special emphasis was given to the charge state probabilities of the 13N recoils. Possible improvements of the system for the measurement of other capture reactions are discussed.

26 citations

Journal ArticleDOI
E. Blanke1, K. Brand1, H. Genz1, A. Richter1, G. Schrieder1 
TL;DR: The performance of the Dynamitron-Tandem accelerator at Bochum with respect to beam energy resolution, stability and reproducibility, and beam intensity is reported in this paper.

21 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the reaction rates of astrophysically important thermonuclear reactions involving low-mass nuclei were analyzed for the temperature range 106 ⩽ T ⌽ 1010 K.

1,305 citations

Journal ArticleDOI
TL;DR: In this article, the authors present new parametrizations based on R-matrix calculations for fusion cross-sections and Maxwellian reactivities for the reactions D(d,n)3He, D (d,p)T, T(d-n)4He and 3He(d.p) 4He.
Abstract: For interpreting fusion rate measurements in present fusion experiments and predicting the fusion performance of future devices or of d-t experiments in present devices, it is important to know the fusion cross-sections as precisely as possible. Usually, it is not measured data that are used, but parametrizations of the cross-section as a function of the ion energy and parametrizations of the Maxwellian reactivity as a function of the ion-temperature. Since the publication of the parametrizations now in use, new measurements have been made and evaluations of the measured data have been improved by applying R-matrix theory. The authors show that the old parametrizations no longer adequately represent the experimental data and present new parametrizations based on R-matrix calculations for fusion cross-sections and Maxwellian reactivities for the reactions D(d,n)3He, D(d,p)T, T(d,n)4He and 3He(d,p)4He

679 citations

Journal ArticleDOI
TL;DR: In this article, a quantitative analysis of the uncertainties in the Big Bang nucleosynthesis (BBN) light element abundance predictions is presented, and the results show that the BBN theory uncertainties are dominated by the following nuclear reactions:
Abstract: Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) have a long history together in the standard cosmology. BBN accurately predicts the primordial light element abundances of deuterium, helium and lithium. The general concordance between the predicted and observed light element abundances provides a direct probe of the universal baryon density. Recent CMB anisotropy measurements, particularly the observations performed by the WMAP satellite, examine this concordance by independently measuring the cosmic baryon density. Key to this test of concordance is a quantitative understanding of the uncertainties in the BBN light element abundance predictions. These uncertainties are dominated by systematic errors in nuclear cross sections, however for helium-4 they are dominated by the uncertainties in the neutron lifetime and Newton's G. We critically analyze the cross section data, producing representations that describe this data and its uncertainties, taking into account the correlations among data, and explicitly treating the systematic errors between data sets. The procedure transforming these representations into thermal rates and errors is discussed. Using these updated nuclear inputs, we compute the new BBN abundance predictions, and quantitatively examine their concordance with observations. Depending on what deuterium observations are adopted, one gets the following constraints on the baryon density: ${\ensuremath{\Omega}}_{\mathrm{B}}{h}^{2}=0.0229\ifmmode\pm\else\textpm\fi{}0.0013$ or ${\ensuremath{\Omega}}_{\mathrm{B}}{h}^{2}{=0.0216}_{\ensuremath{-}0.0021}^{+0.0020}$ at 68% confidence, fixing ${N}_{\ensuremath{ u},eff}=3.0.$ If we instead adopt the WMAP baryon density, we find the following deuterium-based constraints on the effective number of neutrinos during BBN: ${N}_{\ensuremath{ u},eff}{=2.78}_{\ensuremath{-}0.76}^{+0.87}$ or ${N}_{\ensuremath{ u},eff}{=3.65}_{\ensuremath{-}1.30}^{+1.46}$ at 68% confidence. Concerns over systematics in helium and lithium observations limit the confidence constraints based on this data provide. BBN theory uncertainties are dominated by the following nuclear reactions: ${d(d,n)}^{3}\mathrm{He},$ $d(d,p)t,$ $d(p,\ensuremath{\gamma}{)}^{3}\mathrm{He},$ ${}^{3}\mathrm{He}(\ensuremath{\alpha},\ensuremath{\gamma}{)}^{7}\mathrm{Be}$ and ${}^{3}\mathrm{He}{(d,p)}^{4}\mathrm{He}.$ With new nuclear cross section data, light element abundance observations and the ever increasing resolution of the CMB anisotropy, tighter constraints can be placed on nuclear and particle astrophysics.

282 citations

Journal ArticleDOI
TL;DR: The NACRE-II compilation as mentioned in this paper is the most recent compilation of the data and is referred to as NACre II, which reports thermonuclear reaction rates for 34 charged-particle induced, two-body exoergic reactions on nuclides with mass number A 16, of which fifteen are particle transfer reactions and the rest radiative capture reactions.

277 citations