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Construction of a Neutron Ball for Exclusive Electron Scattering Experiments at the S-DALINAC*. A.M. Heilmann, M. Chernykh, P. von Neumann-Cosel, A. Richter. Motivation Experimental setup Experiments Results Summary and outlook. SFB 634. *Supported by the DFG within SFB 634.
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Construction of a Neutron Ball for Exclusive Electron Scattering Experiments at the S-DALINAC* A.M. Heilmann, M. Chernykh, P. von Neumann-Cosel, A. Richter • Motivation • Experimental setup • Experiments • Results • Summary and outlook SFB 634 *Supported by the DFG within SFB 634 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 1
Motivation Isoscalar Giant Dipole Resonance Measurements • exclusive electron coincidence measurements (e,e'n) • almost background-free spectra • supression of the radiative tail • veto detector with a large solid angle S.Strauch, Dissertation, TU Darmstadt (1998) 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 2
Requirements for the Neutron Ball • fast detector response • high neutron efficiency • n/-discrimination • compact geometry • secondary: energy resolution 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 3
Construction of the Neutron Ball • 13 liquid scintillators of the type Bircon BC501A for neutron detection • solid angle of about 1.3π (for 20 cm) 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 4
Test of the Neutron Balln/-Discrimination • AmBe neutron source • zero crossing method 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 5
Test of the Neutron BallPulse-Height Calibration measurement: background monoenergetic sources analysis: dead-time correction background subtraction unfolding starting from high energies 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 6
Test of the Neutron BallUnfolding of Measured Spectra procedure: • pulse-height simulation NRESP • folding with detector resolution • fit to measured spectra results: • energy dependent detector resolution • position of the compton edge • pulse-height calibration 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 7
Summary • design and construction finished • tests performed • n/-discrimination • pulse-height calibration 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 8
Fission ChamberPreparation for Efficiency Determination with 252Cf 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 9
Outlook • efficiency determination with 252Cf • ToF method • single detectors • whole setup • simulations • first measurements with heavy nuclei SFB 634 23.10.2008 | Institut für Kernphysik | Project C2 | Anna Maria Heilmann | 10