| 1. |
- Aguar-Bartolome, P., et al.
(author)
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New determination of the eta transition form factor in the Dalitz decay eta -> e(+) e(-) gamma with the Crystal Ball/TAPS detectors at the Mainz Microtron
- 2014
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 89:4
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Journal article (peer-reviewed)abstract
- The Dalitz decay eta -> e(+) e(-) gamma has been measured in the gamma p -> eta p reaction with the Crystal Ball and TAPS multiphoton spectrometers, together with the photon-tagging facility at the Mainz Microtron MAMI. The experimental statistic used in this work is one order of magnitude greater than in any previous measurement of eta -> e(+) e(-) gamma. The value obtained for the slope parameter Lambda(-2) of the eta transition form factor, Lambda(-2) = (1.95 +/- 0.15(stat) +/- 0.10(syst)) GeV-2, is in good agreement with recent measurements conducted in eta -> e(+) e(-) gamma and eta -> mu(+) mu(-) gamma decays, as well as with recent form-factor calculations. The uncertainty obtained in the value of Lambda(-2) is lower compared to results from previous measurements of the eta -> e(+) e(-) gamma decay.
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| 2. |
- Kashevarov, V. L., et al.
(author)
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Experimental study of the gamma p -> pi (0)pi(0) p reaction with the Crystal Ball/TAPS detector system at the Mainz Microtron
- 2012
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 85:6
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Journal article (peer-reviewed)abstract
- The gamma p -> pi(0)pi(0) p reaction has been measured from threshold to 1.4 GeV using the Crystal Ball and TAPS photon spectrometers together with the photon tagging facility at the Mainz Microtron. The experimental results include total and differential cross sections as well as specific angular distributions, which were used to extract partial-wave amplitudes. In particular, the energy region below the D-13(1520) resonance was studied.
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| 3. |
- Fissum, Kevin, et al.
(author)
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High-resolution measurement of the 12C(γ,p)11B reaction to excited states for Eγ=50–70MeV
- 1998
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In: Physical Review C: covering nuclear physics. - 2469-9985. ; 58:4, s. 2167-2173
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Journal article (peer-reviewed)abstract
- Relative population of states in 11B following the 12C(γ,p) reaction has been measured with high resolution using the deexcitation γ-ray technique. The states near 7 MeV in 11B are clearly resolved and the measured population clarifies earlier conflicting data. Comparison of the results with new calculations indicates the importance of both one-nucleon and multinucleon processes.
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| 4. |
- Sims, D. A., et al.
(author)
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(γ,n) study of the isovector quadrupole resonance in 40Ca
- 1997
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In: Physical Review C: covering nuclear physics. - 2469-9985. ; 55:3, s. 1288-1294
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Journal article (peer-reviewed)abstract
- The forward-to-backward asymmetry of neutrons emitted in the 40Ca(γ,n0) reaction was measured at photon energies in the range of 27–50 MeV. An energy-dependent asymmetry was observed that is interpreted as evidence of interference between the isovector quadrupole resonance and the giant dipole resonance. Data analysis in terms of semiclassical and direct-semidirect models estimate the isovector quadrupole resonance to be at an excitation energy of 31.0±1.5 MeV, with a width of 16.0±1.5 MeV, and exhausting most of the energy-weighted sum rule for the isovector quadrupole resonance.
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| 5. |
- Al Jebali, Ramsey, et al.
(author)
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A helium gas scintillator active target for photoreaction measurements
- 2015
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In: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 51:10
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Journal article (peer-reviewed)abstract
- A multi-cell He gas scintillator active target, designed for the measurement of photoreaction cross sections, is described. The target has four main chambers, giving an overall thickness of 0.103 g/cm(3) at an operating pressure of 2MPa. Scintillations are read out by photomultiplier tubes and the addition of small amounts of N-2 to the He, to shift the scintillation emission from UV to visible, is discussed. First results of measurements at the MAX IV Laboratory tagged-photon facility show that the target has a timing resolution of around 1 ns and can cope well with a high-flux photon beam. The determination of reaction cross sections from target yields relies on a Monte Carlo simulation, which considers scintillation light transport, photodisintegration processes in He-4, background photon interactions in target windows and interactions of the reaction-product particles in the gas and target container. The predictions of this simulation are compared to the measured target response.
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| 6. |
- Morrow, S A, et al.
(author)
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High-resolution study of the C-12(gamma,p gamma')B-11 reaction using a HpGe detector to resolve excited states of B-11 through the observation of their gamma-ray decays
- 2006
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In: Physical Review C: covering nuclear physics. ; 73
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Journal article (peer-reviewed)abstract
- Relative populations of states in 11B following the 12C(,p)11B reaction have been measured with high resolution using a 70% HpGe detector to observe decay rays from the residual nucleus. The triplet of states near 7 MeV in 11B are resolved and the measured populations compared to previous data. The analysis includes a consideration of -proton angular correlations, which was not made in the previous measurement. The new and previous results corrected for angular correlation effects agree reasonably well with calculations that include one- and two-body nuclear currents, pion exchange, and currents, under the assumption that the photons are mainly absorbed on exchanged pions.
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| 7. |
- Reiter, A., et al.
(author)
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Measurement and simulation of the neutron response of the Nordball liquid scintillator array
- 2006
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In: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 565:2, s. 753-762
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Journal article (peer-reviewed)abstract
- The response of the liquid scintillator array Nordball to neutrons in the energy range 1.5 < T-n < 10 MeV has been measured by time of flight using a Cf-252 fission source. Fission fragments were detected by means of a thin-film plastic scintillator. The measured differential and integral neutron detection efficiencies agree well with predictions of a Monte Carlo simulation of the detector which models geometry accurately and incorporates the measured, non-linear proton light output as a function of energy. The ability of the model to provide systematic corrections to photoneutron cross-sections, measured by Nordball at low energy, is tested in a measurement of the two-body deuteron photodisintegration cross-section in the range E-gamma = 14-18 MeV. After correction the present H-2 (gamma, n)p measurements agree well with a published evaluation of the large body of H-2(gamma, p)n data. (c) 2006 Elsevier B.V. All rights reserved.
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| 8. |
- Sims, D. A., et al.
(author)
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The He(γ,n) reaction: a potential testing ground for the alpha-particle wavefunction
- 1998
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In: Physics Letters B. - 0370-2693. ; 442:1-4, s. 43-47
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Journal article (peer-reviewed)abstract
- Differential cross sections (σ(Eγ,θn)) for the He(γ,n) reaction have been measured at Eγ=50–71 MeV and θn=30–120°. These data are compared with theoretical predictions where a microscopic calculation of the He and He wavefunctions has been made within the Alt-Grassberger-Sandhas, integral-equation formalism.
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