The low-energy photon tagger NEPTUN

Savran, D.; Lindenberg, Kai; Glorius, J.; Löher, B.; Müller, Sebastian; Pietralla, N.; Schnorrenberger, L.; Simon, Vanessa V.; Sonnabend, K.; Wälzlein, C.; Elvers, M.; Endres, J.; Hasper, J.; Zilges, A.

doi:10.1016/j.nima.2009.11.038

Cited by 34 publications

(25 citation statements)

References 39 publications

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“…Measurements were performed with continuousenergy bremsstrahlung photons [25,26,27,28,29] and quasi-monoenergetic photons from Laser Compton Backscattering (LCB) [30,31,32] (see [33] as review). In near future, also tagged photons will be available with high energy resolution in the astrophysically relevant energy range at the low-energy photon tagger NEPTUN at the S-DALINAC, Darmstadt [34,35]. Using bremsstrahlung photons, the ground-state reaction rate can be deduced from a series of activations without any assumption on the energy dependence of the cross section [21].…”

Section: Experiments On Photon-induced Reactionsmentioning

confidence: 99%

Activation Experiments forp-Process Nucleosynthesis

Sonnabend¹,

Glorius²,

Knörzer³

et al. 2011

J. Phys.: Conf. Ser.

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Abstract. Activation experiments are a perfect tool to perform systematic studies due to their high sensitivity and selectivity. Exemplary applications to understand the nucleosynthesis of the p nuclei -such as the optimization of optical particle-nucleus potentials and investigations of (γ,n) reactions in a broad mass range -are presented. Some recent and partly preliminary results are briefly discussed.

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Section: Experiments On Photon-induced Reactionsmentioning

confidence: 99%

Activation Experiments forp-Process Nucleosynthesis

Sonnabend¹,

Glorius²,

Knörzer³

et al. 2011

J. Phys.: Conf. Ser.

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“…On stable nuclei, (p, p γ) experiments will allow to further investigate the structure of the PDR. Using tagged photons at the NEPTUN facility [32,33] will allow to close the gap between the IVGDR and the low-energy strength. At this new experimental site, photon-induced experiments can be studied independently of limitations due to the particle thresholds, which will also play an important role in extending systematics on photon-induced reactions for nuclear astrophysics [34, 35,36,37].…”

Section: Discussionmentioning

confidence: 99%

Splitting of the Pygmy Dipole Resonance

Savran

Endres

Harakeh

et al. 2011

J. Phys.: Conf. Ser.

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Abstract.We report on experiments using the (α, α γ) method to investigate the structure of the Pygmy Dipole Resonance (PDR) in the nuclei 94 Mo, 124 Sn, 138 Ba and 140 Ce. The experiments were performed with the Big-Bite Spectrometer (BBS) at the KVI at an incident energy of Eα = 136 MeV. The method allows a clean separation of the PDR from other excitations in the same energy region by selecting the ground-state γ-decay channel. In addition, the high resolution of the γ-ray spectroscopy using high-purity Germanium detectors allows a state-tostate analysis even in the case of the rather high level density of the investigated nuclei. The comparison to (γ, γ ) experiments on the same nuclei reveals a splitting of the PDR into two groups of states with different underlying structure.

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“…Various implementations have involved the detection of Compton electrons from a backscattered electron beam [Pascale 1985], the tagging of positron annihilation in flight [Argan 1984], and the tagging of bremsstrahlung beams [Detemple 1992, Terasawa 1986, Bianchi 1992, Anthony 1991, Sober 2000. This section describes a notional system utilizing tagged bremsstrahlung beams to produce tagged photons in the 10's of MeV range.…”

Section: Overviewmentioning

confidence: 99%

“…In an optimal design such as that of the Jefferson Laboratory Hall B photon tagger [Sober 2000], the post bremsstrahlung detectors on the focal plane of the tagger consist of two rows of plastic scintillator hodoscopes, "E" -and "T" -counters (energy and timing counters). If we assume one wishes to bend a 50 MeV electron beam down 45 o into the beam dump, a 0.12 Tesla • meter magnet is required.…”

Section: Measurement Of Absolute Photonuclear Cross Sections With Thementioning

confidence: 99%

Associated Particle Tagging (APT) in Magnetic Spectrometers

Jordan¹,

Baciak²,

Stave³

et al. 2012

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Summary In BriefThe Associated Particle Tagging (APT) project, a collaboration of Pacific Northwest National Laboratory (PNNL), Idaho National Laboratory (INL) and the Idaho State University (ISU)/Idaho Accelerator Center (IAC), has completed an exploratory study to assess the role of magnetic spectrometers as the linchpin technology in next-generation tagged-neutron and tagged-photon active interrogation (AI). The computational study considered two principle concepts: (1) the application of a solenoidal alpha-particle spectrometer to a next-generation, large-emittance neutron generator for use in the associated particle imaging technique, and (2) the application of tagged photon beams to the detection of fissile material via active interrogation. In both cases, a magnetic spectrometer momentum-analyzes charged particles (in the neutron case, alpha particles accompanying neutron generation in the D-T reaction; in the tagged photon case, post-bremsstrahlung electrons) to define kinematic properties of the relevant neutral interrogation probe particle (i.e. neutron or photon). The main conclusions of the study can be briefly summarized as follows:Neutron generator:• For the solenoidal spectrometer concept, magnetic field strengths of order 1 Tesla or greater are required to keep the transverse size of the spectrometer smaller than 1 meter. The notional magnetic spectrometer design evaluated in this feasibility study uses a 5-T magnetic field and a borehole radius of 18 cm.• The design shows a potential for 4.5 Sr tagged neutron solid angle, a factor of 4.5 larger than achievable with current API neutron-generator designs.• The potential angular resolution for such a tagged neutron beam can be less than 0.5 o for modest Si-detector position resolution (3 mm). Further improvement in angular resolution can be made by using Si-detectors with better position resolution.• The report documents several features of a notional generator design incorporating the alpha-particle spectrometer concept, and outlines challenges involved in the magnetic field design. Tagged photon interrogation:• We investigated a method for discriminating fissile from benign cargo-material response to an energy-tagged photon beam. The method relies upon coincident detection of the tagged photon and a photoneutron or photofission neutron produced in the target material. The method exploits differences in the shape of the neutron production cross section as a function of incident photon energy in order to discriminate photofission yield from photoneutrons emitted by non-fissile materials. Computational tests of the interrogation method as applied to material composition assay of a simple, multi-layer target suggest that the tagged-photon information facilitates precise (order 1% thickness uncertainty) reconstruction of the constituent thicknesses of fissile (uranium) and high-Z (Pb) constituents of the test targets in a few minutes of photon-beam exposure. We assumed an 18-MeV endpoint tagged photon beam for these simulations.• The report addresses ...

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The low-energy photon tagger NEPTUN

Cited by 34 publications

References 39 publications

Activation Experiments forp-Process Nucleosynthesis

Activation Experiments forp-Process Nucleosynthesis

Splitting of the Pygmy Dipole Resonance

Associated Particle Tagging (APT) in Magnetic Spectrometers

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