Measurement of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Np</mml:mi><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>237</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>n</mml:mi><mml:mo>,</mml:mo><mml:mi>γ</mml:mi></mml:mrow></mml:math>) cross section from 20 meV to 500 keV with a high efficiency, highly segmented<mml:math xmlns:m

Esch, Ernst I; Reifarth, R.; Bond, E. M.; Bredeweg, T. A.; Couture, A.; Glover, S. E.; Greife, U.; Haight, R. C.; Hatarik, A. M.; Hatarik, R.; Jändel, M.; Kawano, Toshihiko; Mertz, Aaron F.; O’Donnell, J. M.; Rundberg, R. S.; Schwantes, Jon M.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J.M.

doi:10.1103/physrevc.77.034309

Cited by 42 publications

(24 citation statements)

References 25 publications

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“…The DANCE array consists of 160 equal-volume, equal-solid-angle BaF 2 crystals arranged in a 4π geometry. DANCE has been used to measure neutron-induced reactions on actinides including 237 Np [45] [51]. The detector array is located at the end of a flight path 20.25 m from the neutron source.…”

Section: Methodsmentioning

confidence: 99%

Measurement of theAm242mneutron-induced reaction cross sections

Buckner

Henderson

et al. 2017

Phys. Rev. C

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The neutron-induced reaction cross sections of 242m Am were measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. A new neutron-capture cross section was determined, and the absolute scale was set according to a concurrent measurement of the well-known 242m Am(n,f) cross section. The (n,γ) cross section was measured from thermal to an incident energy of 1 eV at which point the data quality was limited by the reaction yield in the laboratory. Our new 242m Am fission cross section was normalized to ENDF/B-VII.1 to set the absolute scale, and it agreed well with the (n,f) cross section reported by Browne et al. from thermal energy to 1 keV. The average absolute capture-to-fission ratio was determined from thermal to En = 0.1 eV, and it was found to be 26(4)% as opposed to the ratio of 19% from the ENDF/B-VII.1 evaluation.

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Section: Methodsmentioning

confidence: 99%

Measurement of theAm242mneutron-induced reaction cross sections

Buckner

Henderson

et al. 2017

Phys. Rev. C

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“…124) who obtained the RRPs from their transmission measurements. As for 92 Mo, a negative resonance was inserted at À2:45 keV in order to reproduce the measured thermal capture cross section 125) and the thermal scattering cross section recommended by Mughabghab. 109) No resolved resonance is given for 99 Mo.…”

Section: )mentioning

confidence: 99%

JENDL-4.0: A New Library for Nuclear Science and Engineering

Shibata

Iwamoto

Nakagawa

et al. 2011

J. Nucl. Sci. Technol.

175

152

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The fourth version of the Japanese Evaluated Nuclear Data Library has been produced in cooperation with the Japanese Nuclear Data Committee. In the new library, much emphasis is placed on the improvements of fission product and minor actinoid data. Two nuclear model codes were developed in order to evaluate the cross sections of fission products and minor actinoids. Coupled-channel optical model parameters, which can be applied to wide mass and energy regions, were obtained for nuclear model calculations. Thermal cross sections of actinoids were carefully examined by considering experimental data or by the systematics of neighboring nuclei. Most of the fission cross sections were derived from experimental data. A simultaneous evaluation was performed for the fission cross sections of important uranium and plutonium isotopes above 10 keV. New evaluations were performed for the thirty fissionproduct nuclides that had not been contained in the previous library JENDL-3.3. The data for light elements and structural materials were partly reevaluated. Moreover, covariances were estimated mainly for actinoids. The new library was released as JENDL-4.0, and the data can be retrieved from the Web site of the JAEA Nuclear Data Center.

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“…Further details on the overall performance of the array can be found in [7]. For details on the analysis and the neutron flux see [13]). …”

Section: Dancementioning

confidence: 99%

The s-process – overview and selected developments

Reifarth¹

2010

J. Phys.: Conf. Ser.

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Abstract. Almost all of the heavy elements are produced via neutron capture reactions in a multitude of stellar production sites. The predictive power of the underlying stellar models is currently limited because they contain poorly constrained physics components such as convection, rotation or magnetic fields.Neutron captures measurements on heavy radioactive isotopes provide a unique opportunity to largely improve these physics components, and thereby address important questions of nuclear astrophysics. Such species are branch-points in the otherwise uniquely defined path of subsequent neutron captures along the s-process path in the valley of stability. These branch points reveal themselves through unmistakable signatures recovered from pre-solar meteoritic grains that originate in individual element producing stars.Measurements on radioactive isotopes for neutron energies in the keV region represent a stringent challenge for further improvements of experimental techniques. This holds true for the neutron sources, the detection systems and the technology to handle radioactive material. IntroductionAbout 50% of the element abundances beyond iron are produced via slow neutron capture nucleosynthesis (s process). Starting at iron-peak seed, the s-process mass flow follows the neutron rich side of the valley of stability via a sequence of neutron captures and β − decays (see Figure 1) synthesizing the elements between iron and bismuth.If different reaction rates are comparable, the s-process path branches and the branching ratio reflects the physical conditions in the interior of the star. Such nuclei are most interesting, because they provide the tools to effectively constrain modern models of the stars where the nucleosynthesis occurs. As soon as the β − decay is significantly faster than the typically competing neutron capture, no branching will take place. Therefore experimental neutron capture data for the s process are only needed, if the respective neutron capture time under stellar conditions is similar or smaller than the β − decay time, which includes all stable isotopes. Depending on the actual neutron density during the s process, the "line of interest" is closer to or farther away from the valley of stability.The modern picture of the main s-process component refers to the He shell burning phase in AGB stars [1]. Nuclei with masses between 90 and 209 are mainly produced during the main component. The highest neutron densities in this model occur during the 22 Ne(α,n) phase and are up to 10 12 cm −3 with temperatures around kT = 30 keV. The other extreme can be found during the 13 C(α,n) phase where neutron densities as low as 10 7 cm −3 and temperatures around kT = 5 keV are possible. Similarly to the main component, also the weak component referring to different evolutionary stages in massive stars has to phases [2,3]. Mainly nuclei with masses

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Measurement of theNp237(n,γ) cross section from 20 meV to 500 keV with a high efficiency, highly segmented

Cited by 42 publications

References 25 publications

Measurement of theAm242mneutron-induced reaction cross sections

Measurement of theAm242mneutron-induced reaction cross sections

JENDL-4.0: A New Library for Nuclear Science and Engineering

The s-process – overview and selected developments

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