First application of the Oslo method in inverse kinematics
V. W. Ingeberg, S. Siem, M. Wiedeking, K. Sieja, D. L. Bleuel, C.P. Brits, T. D. Bucher, T. S. Dinoko, J. L. Easton, A. Görgen, M. Guttormsen, Peter G. Jones, B. V. Kheswa, N. A. Khumalo, A. C. Larsen, E. A. Lawrie, J. J. Lawrie, S. N. T. Majola, K. L. Malatji, L. Makhathini, B. Maqabuka, D. Negi, S. P. Noncolela, P. Papka, E. Şahin, R. Schwengner, G. M. Tveten, F. Zeiser, B. R. Zikhali
Abstract
Abstract The $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> -ray strength function ( $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> SF) and nuclear level density (NLD) have been extracted for the first time from inverse kinematic reactions with the Oslo method. This novel technique allows measurements of these properties across a wide range of previously inaccessible nuclei. Proton– $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> coincidence events from the $$\mathrm {d}(^{86}\mathrm {Kr}, \mathrm {p}\gamma )^{87}\mathrm {Kr}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>d</mml:mi><mml:msup><mml:mrow><mml:msup><mml:mo>(</mml:mo><mml:mn>86</mml:mn></mml:msup><mml:mi>Kr</mml:mi><mml:mo>,</mml:mo><mml:mi>p</mml:mi><mml:mi>γ</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>87</mml:mn></mml:msup><mml:mi>Kr</mml:mi></mml:mrow></mml:math> reaction were measured at iThemba LABS and the $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> SF and NLD in $$^{87}\mathrm {Kr}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow/><mml:mn>87</mml:mn></mml:msup><mml:mi>Kr</mml:mi></mml:mrow></mml:math> was obtained. The low-energy region of the $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> SF is compared to shell-model calculations, which suggest this region to be dominated by M1 strength. The $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> SF and NLD are used as input parameters to Hauser–Feshbach calculations to constrain $$(\mathrm {n},\gamma )$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>(</mml:mo><mml:mi>n</mml:mi><mml:mo>,</mml:mo><mml:mi>γ</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math> cross sections of nuclei using the TALYS reaction code. These results are compared to $$^{86}\mathrm {Kr}(n,\gamma )$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow/><mml:mn>86</mml:mn></mml:msup><mml:mi>Kr</mml:mi><mml:mrow><mml:mo>(</mml:mo><mml:mi>n</mml:mi><mml:mo>,</mml:mo><mml:mi>γ</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> data from direct measurements.