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論文

Demonstrating the integral resonance transmission method; Conceptual and experimental studies

Angell, C.; 早川 岳人; 静間 俊行; 羽島 良一; Quiter, B. J.*; Ludewigt, B. L.*; Karwowski, H. J.*; Rich, G.*; Silano, J.*

Proceedings of INMM 56th Annual Meeting (Internet), 9 Pages, 2015/07

Nuclear resonance fluorescence (NRF) is a promising technique for assaying $$^{239}$$Pu in spent nuclear fuel and for SNM detection applications because of its isotope-specific nature and potential for high sensitivity. To fully utilize the next generation of high-flux $$gamma$$-ray sources for NRF applications we developed the integral resonance transmission (IRT) method which integratesover all resonances within the energy width of a quasi-monoenergetic $$gamma$$-ray beam allowing the full utilization of the transmission signature. To realize the IRT technique both conceptual studies, exploring the consequences of the loss of resolution, and experimental studies, demonstrating several aspects of the IRT method, were undertaken. The conceptual studies included the development of a performance metric allowing comparison between using the IRT technique and single resonances, a study of the magnitude of resonance overlap, and beam simulations examining performance as a function of beam width. The experimental studies were done at the HI$$gamma$$S facility at Duke University, and included an experiment constraining resonance overlap in a NRF transmission measurement through a TMI-2 type canister, demonstration of the IRT technique by a NRF measurement on $$^{181}$$Ta, and the world's first transmission NRF measurement on $$^{239}$$Pu. In this talk, we will overview each component of the conceptual and experimental studies for the IRT method.

論文

Demonstration of a transmission nuclear resonance fluorescence measurement for a realistic radioactive waste canister scenario

Angell, C.; 羽島 良一; 早川 岳人; 静間 俊行; Karwowski, H.*; Silano, J.*

Nuclear Instruments and Methods in Physics Research B, 347, p.11 - 19, 2015/03

 被引用回数:8 パーセンタイル:65.81(Instruments & Instrumentation)

Transmission nuclear resonance fluorescence (NRF) is a promising method for precision non-destructive assay (NDA) of fissile isotopes including $$^{239}$$Pu in spent fuel while inside a storage canister. The assay, however, could be confounded by the presence of overlapping resonances from competing isotopes in the canister. A measurement is needed to demonstrate that transmission NRF is unaffected by the shielding material. To this end, we carried out a transmission NRF measurement using a mono-energetic $$gamma$$-ray beam on a proxy target (Al) and absorbing material simulating a realistic spent fuel storage canister. Similar amounts of material as would be found in a possible spent fuel storage canister were placed upstream: concrete, stainless steel (SS 304), lead (as a proxy for U), and water. An Al absorption target was also used as a reference. These measurements demonstrated that the canister material should not significantly influence the non-destructive assay.

論文

Erratum; Evidence for radiative coupling of the pygmy dipole resonance to excited states [Phys. Rev. C 86, 051302(R) (2012)]

Angell, C.; Hammond, S. L.*; Karwowski, H. J.*; Kelley, J. H.*; Krti$v{c}$ka, M.*; Kwan, E.*; 牧永 あや乃*; Rusev, G.*

Physical Review C, 91(3), p.039901_1 - 039901_2, 2015/03

AA2014-0872.pdf:0.1MB

 被引用回数:5 パーセンタイル:78.67(Physics, Nuclear)

The present manuscript is an erratum to a previously published paper "Evidence for radiative coupling of the pygmy dipole resonance to excited states" [Phys. Rev. C 86, 051302(R) (2012)].

論文

Improving the assay of $$^{239}$$Pu in spent and melted fuel using the nuclear resonance fluorescence integral resonance transmission method

Angell, C.; 早川 岳人; 静間 俊行; 羽島 良一; Quiter, B. J.*; Ludewigt, B. L.*; Karwowski, H.*; Rich, G.*

Nuclear Physics and $$gamma$$-ray sources for Nuclear Security and Nonproliferation, p.133 - 141, 2014/12

Non-destructive assay (NDA) of $$^{239}$$Pu in spent nuclear fuel is possible using the isotope-specific nuclear resonance fluorescence (NRF) integral resonance transmission (IRT) method. The IRT method measures the absorption of photons from a quasi-monoenergetic $$gamma$$-ray beam due to all resonances in the energy width of the beam. According to calculations the IRT method could greatly improve assay times for $$^{239}$$Pu in nuclear fuel. To demonstrate and verify the IRT method, we first measured the IRT signature in $$^{181}$$Ta, and subsequently made IRT measurements in $$^{239}$$Pu. These measurements were done using the quasi-monoenergetic beam at the High Intensity $$gamma$$-ray Source (HI$$gamma$$S) in Durham, NC, USA. The IRT signature was observed as a decrease in scattering strength when the same isotope material was placed in the beam line upstream of the scattering target. The results confirm the validity of the IRT method in both $$^{181}$$Ta and $$^{239}$$Pu.

論文

Validating resonance properties using nuclear resonance fluorescence

Angell, C.; 羽島 良一; 早川 岳人; 静間 俊行; Karwowski, H.*; Silano, J.*

Physical Review C, 90(5), p.054315_1 - 054315_6, 2014/11

AA2014-0567.pdf:0.3MB

 被引用回数:5 パーセンタイル:42.25(Physics, Nuclear)

Measurement of a resonance's integrated cross section using nuclear resonance fluorescence can be a valuable tool for verifying the properties of the resonance because of the clear and unambiguous physical connection to the spin, lifetime, and ground state branching ratio of the level. We demonstrate this idea by measuring the integrated cross section of the 3.004 MeV level in $$^{27}$$Al to 4% using the mono-energetic $$gamma$$-ray beam at the High Intensity $$gamma$$-ray Source. That level was the subject of much debate experimentally in the 1960's, especially its spin, and even now only has a current tentative spin assignment of $$J=(9/2)$$. The consistency check between this integrated cross section and the known properties of the level indicate that one (or more)of the literature properties is incorrect. Based on the range of extent of each property, a re-assignment of spin to atentative $$J=(7/2)$$ may be warranted, but this would need to be confirmed with other measurements. This result demonstrates the utility of NRF as a way to verify the properties of states in the literature before undertaking more extensive measurements.

論文

Demonstration of the nuclear resonance fluorescence integral resonance transmission method for NDA of debris of melted nuclear fuel

Angell, C.; 早川 岳人; 静間 俊行; 羽島 良一; Quiter, B. J.*; Ludewigt, B. L.*; Karwowski, H.*; Rich, G.*

Proceedings of INMM 54th Annual Meeting (CD-ROM), 7 Pages, 2013/07

Non-destructive assay (NDA) of $$^{239}$$Pu in spent nuclear fuel is possible using the isotope-specific nuclear resonance fluorescence (NRF) integral resonance transmission (IRT) method. The IRT method measures the absorption of photons from a quasi-monoenergetic $$gamma$$-ray beam due to all resonances in the energy width of the beam. According to calculations the IRT method could greatly improve assay times for $$^{239}$$Pu in nuclear fuel. To demonstrate and verify the IRT method, we measured the IRT signature in a simulant material, $$^{181}$$Ta, whose nuclear resonant properties are similar to those of $$^{239}$$Pu. Measurements were made at beam energies of 2.27 and 2.75 MeV, using metallic Ta for both the absorption and scattering targets. The scattered radiation was measured using HPGe and LaBr detectors. The results confirm the validity of the IRT method and a similar result is expected on $$^{239}$$Pu.

論文

Evidence for radiative coupling of the pygmy dipole resonance to excited states

Angell, C.; Hammond, S. L.*; Karwowski, H.*; Kelley, J.*; Krti$v{c}$ka, M.*; Kwan, E.*; 牧永 あや乃*; Rusev, G.*

Physical Review C, 86(5), p.051302_1 - 051302_5, 2012/11

 被引用回数:51 パーセンタイル:92.73(Physics, Nuclear)

The photoabsorption cross section and ground state branching ratio of $$^{142}$$Nd were measured using quasi-monoenergetic $$gamma$$-ray beams at several beam energies. Two peaks corresponding to the isovector pygmy dipole resonance (PDR) were identified. The branching ratios were compared to statistical-model calculations. We found that the Brink hypothesis is violated, and that the branching ratios are only reproduced by assuming that the observed isovector PDR selectively decays to the isoscalar PDR.

口頭

Violation of the brink hypothesis in $$^{142}$$Nd

Angell, C.; Hammond, S. L.*; Karwowski, H. J.*; Kelley, J. H.*; Krti$v{c}$ka, M.*; Kwan, E.*; Makinaga, A.*; Rusev, G.*

no journal, , 

The photoabsorption cross section and ground state branching ratio of $$^{142}$$Nd were measured using quasi-monoenergetic $$gamma$$-ray beams at several beam energies, using a $$(gamma,gamma')$$ and a $$(gamma,n)$$ reaction. Two peaks corresponding to the isovectorpygmy dipole resonance (PDR) were identified. The branching ratios were compared to statistical model calculations using the photoabsorption cross section as the radiative strength function. We found that the Brink hypothesis is violated. Extensions to the statistical model to explain the experimental data were attempted, and suggest a new radiative decay mode of the PDR.

口頭

Transmission nuclear resonance fluorescence demonstration experiment for a realistic container scenario for Fukushima melted fuel

Angell, C.; 早川 岳人; 静間 俊行; 羽島 良一; Karwowski, H.*; Silano, J.*

no journal, , 

Nuclear resonance fluorescence in transmission is a promising method for precision assay of the $$^{239}$$Pu in melted fuel from Fukushima. To demonstrate the method can be used for assaying melted fuel inside its final storage container, and that the measurement is unaffected by the shielding material, we carried out a realistic measurement on a proxy target (Al) placing similar amounts of expected shielding material upstream. This demonstrated that the container material does not influence the assay.

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