| 1. |
- Ahrens, J, et al.
(author)
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Intermediate resonance excitation in the gamma p -> p pi(0)pi(0) reaction
- 2005
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In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 624:3-4, s. 173-180
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Journal article (peer-reviewed)abstract
- The helicity dependence of the total cross section for the (gamma) over right arrow(p) over right arrow -> p pi(0)pi(0) reaction has been measured for the first time at incident photon energies from 400 to 800 MeV. The measurement, performed at the tagged photon beam facility of the MAMI accelerator in Mainz, used the large acceptance detector DAPHNE and a longitudinally polarized frozen-spin target. This channel is found to be excited predominantly when the photon and proton have a parallel spin orientation, most likely due to the intermediate production of the D-13(1520) resonance. However, the contribution of the antiparallel spin configuration, arising from other reaction mechanisms, is also not negligible. This result gives important new information to resolve the existing model discrepancies in the identification of the nucleon resonances contributing to this channel.
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| 2. |
- Briscoe, W. J., et al.
(author)
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Nuclear physics program at MAX-lab
- 2009
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In: Chinese Physics C. - : IOP Publishing. - 0899-9996 .- 1674-1137. ; 33:12, s. 1159-1166
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Conference paper (peer-reviewed)abstract
- The upgrade of the MAX-lab Injector and the construction of MAX III, provided the opportunity for upgrading the tagged-photon facility and thus lead to the possibility of more extensive program in nuclear physics research This upgrade increased the injected electron energy to all eventual maximum of 250 MeV and allows for the extraction of electrons from the MAX I ring operated in the stretcher mode The first stretched bean was delivered in September 2005. The tagged-photon facility was commissioned in parallel with the commissioning of new experimental equipment. The PAC approved experimental program is current in progress, including measurement of pion photoproduction below the Delta(1232) The efforts at the tagged photon-facility are pursed within all international collaboration with around fifty members
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| 3. |
- Dutz, H, et al.
(author)
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Measurement of helicity-dependent photoabsorption cross sections on the neutron from 815 to 1825 MeV
- 2005
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In: Physical Review Letters. - 1079-7114. ; 94
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Journal article (peer-reviewed)abstract
- Helicity-dependent total photoabsorption cross sections on the deuteron have been measured for the first time at ELSA (Bonn) in the photon energy range from 815 to 1825 MeV. Circularly polarized tagged photons impinging on a longitudinally polarized LiD target have been used together with a highly efficient 4 pi detector system. The data around 1 GeV are not compatible with predictions from existing multipole analyses. From the measured energy range an experimental contribution to the GDH integral on the neutron of [33.9 +/- 5.5(stat)+/- 4.5(syst)] mu b is extracted.
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| 4. |
- Feldman, G., et al.
(author)
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Compton scattering from deuterium and the polarizabilities of the neutron
- 2008
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In: Few-Body Systems. - : Springer Science and Business Media LLC. - 0177-7963 .- 1432-5411. ; 44:1-4, s. 325-328
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Conference paper (peer-reviewed)abstract
- A new program of Compton scattering on deuterium is under way at the tagged-photon facility at MAX-Lab in Lund, Sweden. We will measure differential cross sections between 60A degrees and 150A degrees over the photon energy range 60-115 MeV in 5 MeV steps, with the ultimate goal of obtaining new precision information on the electric and magnetic polarizabilities of the neutron.
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| 5. |
- Fissum, Kevin, et al.
(author)
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The Coherent Bremsstrahlung Beam at MAX-lab Facility
- 2008
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In: Charged and Neutral Particles Channeling Phenomena Channeling 2008 : Proceedings of the 51st Workshop of the INFN ELOISATRON Project - Proceedings of the 51st Workshop of the INFN ELOISATRON Project. - : WORLD SCIENTIFIC. ; , s. 49-61
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Conference paper (peer-reviewed)abstract
- The linearly polarized photon beam for photonuclear researches has been produced at MAX-lab facility on the base of coherent bremsstrahlung process of electrons in a diamond crystal. Test experiments have been performed at electron energies 143.9 and 192.7 MeV with a diamond crystal 0.1 mm thick. The measured coherent bremsstrahlung spectra demonstrate typical features to be observed at higher electron energies. The polarization ~35% was obtained at coherent peak energy of ~60 MeV. The experiments have shown that produced polarized photon beam can be used for photonuclear investigations at energy range up to 60 MeV. To extend the energy range it is necessary to increase maximal energy of the electron beam up to 250 MeV.
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| 6. |
- Ganenko, V., et al.
(author)
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Production of linearly polarized photon beam at MAX-lab
- 2009
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In: Voprosy Atomnoj Nauki i Techniki. - 1562-6016. ; :3, s. 95-102
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Journal article (peer-reviewed)abstract
- Spectra of coherent bremsstrahlung from the diamond crystal in the laboratory MAX-lab on the accelerator MAX-I are measured at the energy of the electronic beam 144 MeV. First in the laboratory MAX-lab a source of the polarized photon radiation was created. Photon spectra were compared with theoretical calculations, that allow to estimate a magnitude of photon polarization, which is sufficient, for performing the nuclear experiments in the intermediate energy range.
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| 7. |
- Golubev, Pavel, et al.
(author)
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Pion Emission in H-2,C-12,Al-27(gamma,pi+) Reactions at Threshold
- 2008
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In: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 806:1-4, s. 216-229
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Journal article (peer-reviewed)abstract
- The very first data from MAX-lab in Lund, Sweden on pion photoproduction at threshold energies are presented. The decrease of the total π+ yield in γ+12C, 27Al reactions below 200 MeV as well as the dσ/dΩ cross-section data essentially follow the predictions of an intranuclear-cascade model with an attractive potential for the pion–nucleus interaction. However, View the MathML source, cross-section data at 176 MeV show deviations which call for refinements of the model and possibly also for the inclusion of coherent pion-production mechanisms.
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| 8. |
- Hansen, Thorsten, et al.
(author)
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A molecule wired: Electrostatic investigation
- 2005
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In: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 405:1-3, s. 118-122
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Journal article (peer-reviewed)abstract
- We present calculations of ground state and excitation energies for ethene between metal electrodes. The model determines the effects of the electrodes by incorporating a heterogeneous and structured solvation model with the quantum mechanical description of the molecular system. The effects of the electrodes are of electrostatic origin and an external bias can be applied enabling a close connection to the actual physical process related to the measurements of charge transport in molecules located between electrodes.
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| 9. |
- Lee, V., et al.
(author)
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Imaging high energy photons with PILATUS II at the tagged photon beam at MAX-lab
- 2009
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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. ; 603:3, s. 379-383
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Journal article (peer-reviewed)abstract
- In photonuclear experiments precise location of the photon beam relative to the experimental sample is critical. Previously used techniques such as using photographic film to identify the position, intensity and centroid of the beam is time-consuming and a faster method is required. PILATUS is a single-photon-counting pixel detector developed at the Paul Scherrer Institute (PSI), Switzerland. It is a silicon-based, two-dimensional detector with a large dynamic range and zero readout noise. Designed as an X-ray detector, its optimal quantum efficiency is between 3 and 30 keV. This paper reports measurements carried out at the MAX-lab tagged photon facility in Lund, Sweden. The beam endpoint energy of approximately 200 MeV is far above the designed optimal energy detection range of PILATUS, and provides a critical test of the use of PILATUS under high energy conditions. The detector was placed in the photon beam and images were taken both downstream of other experiments, and in close range of a 19 mm collimator. The successful measurements demonstrate the versatility and robustness of the detector and provide an effective way of quickly and accurately monitoring beam position and profile in real time. (C) 2009 Elsevier B.V. All rights reserved.
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| 10. |
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