| 1. |
- Adler, Jan-Olof, et al.
(författare)
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The upgraded photon tagging facility at the MAX IV Laboratory
- 2013
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 715, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- A description is given of the upgraded photon tagging facility at the MAX IV Laboratory. Two magnetic spectrometers are used to momentum analyze post-bremsstrahlung electrons. The tagged photon range extends from 10 to 180 MeV with an energy resolution of about 300 keV. The system has been operated at rates up to 4 x 10(6) photons s(-1) MeV (-1). Different diagnostic tools are described as well as the experimental program.
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| 2. |
- Ganenko, V., et al.
(författare)
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Linearly polarized photon beam at MAX-lab
- 2014
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 763, s. 137-149
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Tidskriftsartikel (refereegranskat)abstract
- A linearly polarized photon beam has been produced at MAX-lab using the coherent bremsstrahlung of electrons with an energy of 192.6 MeV in a 0.1 mm thick diamond crystal. The intensity and shape of the coherent maxima and their dependence on the crystal orientation are similar to the features observed at higher electron energies (similar to 1 GeV) and are well described by coherent bremsstrahlung theory. The linear polarization of the uncollimated beam at the coherent peak energy approximate to 50-60 MeV is about 20% and can be increased to 40-45% if collimation of half the characteristic angle is used At present the degree of polarization is high enough to allow the study of polarization observables in photo-nuclear reactions at MAX-lab in the energy range from Giant Dipole Resonance up to approximate to 80 MeV. (C) 2014 Elsevier B.V. All rights reserved.
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| 3. |
- Jebali, R., et al.
(författare)
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A first comparison of the responses of a He-4-based fast-neutron detector and a NE-213 liquid-scintillator reference detector
- 2015
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 794, s. 102-108
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Tidskriftsartikel (refereegranskat)abstract
- A first comparison has been made between the pulse-shape discrimination characteristics of a novel He-4-based pressurized scintillation detector and a NE-213 liquicl-scintillator reference detector using an Am/Be mixed-field neutron and gamma-ray source and a high-resolution scintillation-pulse digitizer. In particular, the capabilities of the two fast neutron detectors to discriminate between neutrons and gamma-rays were investigated. The NE-213 liquicl-scintillator reference cell produced a wide range of scintillation-light yields in response to he gamma-ray field of the source. In stark contrast, clue to the size and pressure of the He-4 gas volume, the He-4-based detector registered a maximum scintillation-light yield of 750 keV(ee) to the same gamma-ray field. Pulse-shape discrimination for particles with scintillation-light yields of more than 750 keV(ee) was excellent in the case of the He-4-based detector. Above 750 keV(ee) its signal was unambiguously neutron, enabling particle identification based entirely upon the amount of scintillation light produced. (C) 2015 The Authors. Published by Elsevier B.V.
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| 4. |
- Makonyi, Karoly, et al.
(författare)
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Evaluating vacuum phototriodes designed for the PANDA electromagnetic calorimeter
- 2014
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 763, s. 36-43
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Tidskriftsartikel (refereegranskat)abstract
- In this work properties of a vacuum phototriode (VPT) and preamplifier unit designed for the electromagnetic calorimeter of the PANDA experiment being built at FAIR are investigated. With the use of lead tungstate and lanthanium bromide scintillators the VPT properties are studied at low photon energies, from tens of key in the lanthanium bromide measurements and between 10 MeV and 60 MeV in the lead tungstate measurements. At these energies the noise of the VPT unit can be expected to influence its performance significantly. It is shown that the noise contribution to the measured energy resolution, under optimal conditions, is consistent with a fluctuation of (one standard deviation) approximately 200 electrons at the VPT anode. For a lead tungstate crystal this is equivalent to a noise of 1.2 MeV. For lanthanium bromide this makes it possible to use VPTs for gamma ray spectroscopy above a few hundreds of keV without noticeable effects on the energy resolution compared to measurements with a standard photomultiplier.
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| 5. |
- Marcks von Wurtemberg, Klas, et al.
(författare)
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The response of lead-tungstate scintillators (PWO) to photons with energies in the range 13 MeV-64 MeV
- 2012
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 679, s. 36-43
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Tidskriftsartikel (refereegranskat)abstract
- The response of a matrix of 25 lead tungstate (PWO) scintillator detectors, operated at -25 degrees C, to photons in the range 13 MeV-64 MeV has been measured at the tagged-photon facility at MAX-lab, Lund. The tapered PWO crystals, each with a length of 200 mm and a cross-section of 24.4 x 24.4 mm(2) in the front end, read out by 19 mm photomultiplier tubes, were arranged in a 5 x 5 matrix. The response was measured for photons directed towards the centre of the central crystal as well as for photons directed towards the corner of the central crystal, where four crystals meet. The obtained energy resolution surpasses what has been published so far and is close to the limit given by Poisson statistics and escaped energy. For photons directed towards the centre(corner) of the central crystal the relative energy resolution, defined as (FWHM/2.35)/E-gamma, decreases from 7.3%(11.0%) at E-gamma = 13 MeV to 3.3%(3.6%) at E-gamma = 64 MeV. The reconstructed point of impact of a photon in this energy range is determined with an uncertainty (one standard deviation) of 7.3 +/- 0.1 mm.
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| 6. |
- Preston, M. F., et al.
(författare)
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Tests of the Monte Carlo Simulation of the Photon-Tagger Focal-Plane Electronics at the MAX IV Laboratory
- 2014
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 744, s. 17-17
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Tidskriftsartikel (refereegranskat)abstract
- Rate-dependent effects in the electronics used to instrument the tagger focal plane at the MAX IV Laboratory were recently investigated using the novel approach of Monte Carlo simulation to allow for normalization of high-rate experimental data acquired with single-hit time-to-digital converters (TDCs). The instrumentation of the tagger focal plane has now been expanded to include multi-hit TDCs. The agreement between results obtained from data taken using single-hit and multi-hit TDCs demonstrate a thorough understanding of the behavior of the detector system.
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| 7. |
- Reiter, A., et al.
(författare)
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Measurement and simulation of the neutron response of the Nordball liquid scintillator array
- 2006
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Ingår i: 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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Tidskriftsartikel (refereegranskat)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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