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First Proton-Induced Cross Sections on a Stored Rare Ion Beam: Measurement of 118Te(p,γ) for Explosive Nucleosynthesis

F. Dellmann, J. Glorius, Yu. A. Litvinov, R. Reifarth, L. Varga, M. Aliotta, F. Amjad, K. Blaum, L. Bott, C. Brandau, B. Brückner, C. G. Bruno, R. -J. Chen, T. Davinson, T. Dickel, I. Dillmann, D. Dmytriev, P. Erbacher, O. Forstner, D. Freire-Fernández, H. Geissel, K. Göbel, C. J. Griffin, R. E. Grisenti, A. Gumberidze, E. Haettner, S. Hagmann, T. Heftrich, M. Heil, R. Heß, P. -M. Hillenbrand, C. Hornung, R. Joseph, B. Jurado, E. Kazanseva, K. Khasawneh, R. Knöbel, D. Kostyleva, C. Kozhuharov, I. Kulikov, N. Kuzminchuk, D. Kurtulgil, C. Langer, G. Leckenby, C. Lederer-Woods, M. Lestinsky, S. Litvinov, B. Löher, B. Lorentz, E. Lorenz, J. Marsh, E. Menz, T. Morgenroth, I. Mukha, N. Petridis, U. Popp, A. Psaltis, S. Purushothaman, E. Rocco, P. Roy, M. S. Sanjari, C. Scheidenberger, M. Sguazzin, R. S. Sidhu, U. Spillmann, M. Steck, T. Stöhlker, A. Surzhykov, J. A. Swartz, Y. Tanaka, H. Törnqvist, D. Vescovi, M. Volknandt, H. Weick, M. Weigand, P. J. Woods, T. Yamaguchi, J. Zhao

Abstract

We present the first nuclear cross-section measurements of (p,γ) and (p,n) reactions on 118Te at energies relevant for the γ-process nucleosynthesis. Absolute cross-section values for center-of-mass energies of 6, 7 and 10 MeV are provided, together with a theoretical extrapolation to the Gamow window. This experiment marks the first time that direct proton-induced reactions have been measured on a radioactive ion beam at the Experimental Storage Ring (ESR) at GSI, Darmstadt. This paves the way for a large variety of measurements, delivering new constraints for explosive nucleosynthesis and for physics beyond nuclear stability.

First Proton-Induced Cross Sections on a Stored Rare Ion Beam: Measurement of 118Te(p,γ) for Explosive Nucleosynthesis

Abstract

We present the first nuclear cross-section measurements of (p,γ) and (p,n) reactions on 118Te at energies relevant for the γ-process nucleosynthesis. Absolute cross-section values for center-of-mass energies of 6, 7 and 10 MeV are provided, together with a theoretical extrapolation to the Gamow window. This experiment marks the first time that direct proton-induced reactions have been measured on a radioactive ion beam at the Experimental Storage Ring (ESR) at GSI, Darmstadt. This paves the way for a large variety of measurements, delivering new constraints for explosive nucleosynthesis and for physics beyond nuclear stability.

Paper Structure

This paper contains 1 equation, 3 figures, 1 table.

Figures (3)

  • Figure 1: Overview drawing of the ESR with a zoom on the internal gas-jet target and recoil detection areas. The separation of the reaction products inside the dipole magnet is shown schematically. The (p,$\gamma$) and (p,n) recoil ions are intercepted by the Si detector at the end of the dipole, while the ERASE scraper blocks most of the Rutherford scattering background directly before the magnet entrance. HPGe detectors surround the target area to measure the characteristic X-ray emission of the atomic electron-capture process used for normalization of the nuclear cross sections.
  • Figure 2: Ion-hit distribution recorded with the DSSD for a measurement time of 52 h with $^{118}$Te ions stored at 6 MeV/nucleon. The central bump within the red contour originates from the $^{118}$Te(p,$\gamma$) reaction, while $^{118}$Te ions elastically scattering off the hydrogen target atoms produce the background distribution on the upper right. The ERASE blocking removes the dominant part of this Rutherford cone below the (p,$\gamma$) peak, but a weak tail, presumably from secondary scattering off the scraper edge, still extends into this region.
  • Figure 3: Cross sections of $^{118}$Te(p,$\gamma$) in red and $^{118}$Te(p,n) in blue are depicted for the measurement region and the Gamow window at $T = 3$ GK. The experimental data is shown in overlay with TALYS calculations based on the three parameter sets that generate the best reproduction. The gray band represents the full parameter space available in TALYS without individual tuning of the underlying models.