| 1. |
- Al Jebali, Ramsey, et al.
(författare)
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A helium gas scintillator active target for photoreaction measurements
- 2015
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 51:10
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Mauritzson, Nicholai, et al.
(författare)
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GEANT4-based calibration of an organic liquid scintillator
- 2022
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 1023
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Tidskriftsartikel (refereegranskat)abstract
- A light-yield calibration of an NE 213A organic liquid scintillator detector has been performed using bothmonoenergetic and polyenergetic gamma-ray sources. Scintillation light was detected in a photomultipliertube, and the corresponding pulses were subjected to waveform digitization on an event-by-event basis. Theresulting Compton edges have been analyzed using a GEANT4 simulation of the detector which models boththe interactions of the ionizing radiation as well as the transport of scintillation photons. The simulation is calibrated and also compared to well-established prescriptions used to determine the Compton edges,resulting ultimately in light-yield calibration functions. In the process, the simulation-based method produced information on the gain and intrinsic pulse-height resolution of the detector. It also facilitated a previously inaccessible understanding of the systematic uncertainties associated with the calibration of the scintillation-light yield. The simulation-based method was also compared to well-established numerical prescriptions for locating the Compton edges. Ultimately, the simulation predicted as much as 17% lower light-yield calibrations than the prescriptions. These calibrations indicate that approximately 35% of the scintillation light associated with a given gamma-ray reaches the photocathode. It is remarkable how well two 50 year old prescriptions for calibrating scintillation-light yield in organic scintillators have stood the test of time.
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| 3. |
- Sims, D. A., et al.
(författare)
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The He(γ,n) reaction: a potential testing ground for the alpha-particle wavefunction
- 1998
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Ingår i: Physics Letters B. - 0370-2693. ; 442:1-4, s. 43-47
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Tidskriftsartikel (refereegranskat)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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