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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Np(BH4)4 by Materials Project

Np(BH4)4 is Protactinium structured and crystallizes in the tetragonal P4_2/nmc space group. The structure is zero-dimensional and consists of two Np(BH4)4 clusters. Np4+ is bonded to twelve H+0.50+ atoms to form NpH12 cuboctahedra that share faces with four equivalent BH4 tetrahedra. There are eight shorter (2.25 Å) and four longer (2.26 Å) Np–H bond lengths. B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share a faceface with one NpH12 cuboctahedra. There is one shorter (1.20 Å) and three longer (1.26 Å) B–H bond length. There are three inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to one Np4+ and one B3- atom. In the third H+0.50+ site, H+0.50+ is bonded in a distorted single-bond geometry to one Np4+ and one B3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(IO3)4 by Materials Project

Np(O3I)4 crystallizes in the tetragonal P4_2/n space group. The structure is one-dimensional and consists of two Np(O3I)4 ribbons oriented in the (0, 0, 1) direction. Np4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.35 Å) and four longer (2.36 Å) Np–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Np4+ and one I5+ atom. The O–I bond length is 1.87 Å. In the second O2- site, O2- is bonded in a single-bond geometry to one I5+ atom. The O–I bond length is 1.81 Å. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Np4+ and one I5+ atom. The O–I bond length is 1.85 Å. I5+ is bonded in a 3-coordinate geometry to three O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Gamma-ray imaging of Np-237 metal using an organic glass imager

Neutron and gamma-ray imaging systems are deployed within the field of nuclear safeguards for the detection and localization of special nuclear materials and other materials of interest. 237 Np is one of these materials of interest due its presence in spent nuclear fuel and potential for use in nuclear weapons when purified. Here, for the first time, a 6 kg neptunium sphere (98.8 wt% 237 Np) was measured using a dual-particle imager, from the University of Michigan, consisting of organic glass and inorganic scintillators. The novel composition of organic glass scintillator was recently developed at Sandia National Labs and has been used in particle imaging systems due to its time resolution and particle discrimination capabilities. Gamma-ray energy spectra from single and coincident events were extracted and the sequencing of Compton scatter and photoelectric absorption gamma-ray events was used to generate images using simple backprojection. The emissions of interest in this work are the 312 keV and 416 keV gamma rays from 233 Pa, a daughter isotope from the neptunium decay series. The results of this work show that there is close agreement between the true source location in angular space and the converged location from the gamma ray images created using the system. The gamma spectroscopy from single and coincident events also identified the characteristic emission from the daughter isotope and could be used to assist with the identification of 237 Np. Furthermore, successful localization of the source with 5 s of data demonstrates the practical application of the imaging system for imaging and detection of material in weapons-useable quantities.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Rapid analysis of 237 Np and Pu isotopes in unseparated sample matrices using ICP-MS/MS

Inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) is an emerging technique for measuring actinide isotopes when assessing pre- and post- detonation nuclear material. In this study, ICP-MS/MS was investigated for direct Np and Pu quantitation in unseparated, dissolved bulk soil matrices. To achieve this, purified nitric oxide (NO) was investigated for the reactivity of Th, Np, U, Pu, Am, and Cm. Purifying NO prior to the collision reaction cell (CRC) results in increased sensitivity and allows for higher gas flows to be utilized for the removal of interferences. Here, the interference from uranium hydrides was mitigated to less than 3.85 x 10 -11 . This method was demonstrated on standard reference materials which were measured for 237 Np and 238,239,240 Pu in dilute sample digestions. The 238 Pu measurement was validated by spiking into a standard reference material and was accurately measured with an excess of 85000 of 238 U.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

A new TEVA-DGA chromatography procedure to separate Pu, Am, and Np from bulk U materials

Trace actinides present within uranium (U) material are diagnostic signatures of U processing history. For example, the emplacement of U material within the high neutron-flux environment of a nuclear reactor can cause neutron capture of U to form 241-plutonium ( 241 Pu). Plutonium-241 then decays to progeny isotopes 241-americium ( 241 Am) and 237-neptunium ( 237 Np); therefore, the presence and relative abundances of these trace actinides is indicative of the material’s production history and intended employment (Mayer et al., 2013). During a pre-detonation nuclear forensics investigation, measurement of trace actinide 241 Pu, 241 Am, and 237 Np concentrations by an analytical laboratory may be requested. However, chemically purifying these elements from bulk U is a challenging and involved procedure requiring several sequential chromatography columns across 4+ days. To expedite Pu-Am-Np separation from bulk U material, and to improve the yield recovery of these elements, this DHS Postdoc Fellowship has worked to create a new chromatography separation chemistry.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
NASA NTRS1978

Gamma-rays of 3 to 25 MeV from the galactic anti-center and pulsar NP 0532

Gamma-rays of 3 to 25 MeV are reported from the galactic anticenter region and the Crab Pulsar, NP 0532. The observations were carried out from Palestine, Texas, on May 13, 1975. Gamma-rays from the galactic anticenter were observed as the Crab Nebula passed overhead within 10 deg of the zenith. Pulsed gamma-rays from NP 0532 were observed at a 4.4-sigma significance level. The total flux from 3-25 MeV is 0.0049 + or - 0.002 photon/sq cm-sec. The pulsed flux from NP 0532 from 3 to 25 MeV is 0.00043 + or - 0.00026 photon/sq cm-sec. The ratio of the total to the pulsed flux from 3 to 25 MeV is 11 + or - 8.

Wilson, R. B.↗
DOE OSTI2020

Materials Data on Np(CrSi)2 by Materials Project

Np(CrSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Np3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Np–Si bond lengths are 3.01 Å. Cr+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing CrSi4 tetrahedra. All Cr–Si bond lengths are 2.38 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Np3+, four equivalent Cr+2.50+, and one Si4- atom. The Si–Si bond length is 2.34 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(SiAu)2 by Materials Project

Np(AuSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Np7+ is bonded to eight equivalent Si4- atoms to form NpSi8 hexagonal bipyramids that share corners with sixteen equivalent AuSi4 tetrahedra, edges with four equivalent NpSi8 hexagonal bipyramids, edges with eight equivalent AuSi4 tetrahedra, and faces with four equivalent NpSi8 hexagonal bipyramids. All Np–Si bond lengths are 3.18 Å. Au+0.50+ is bonded to four equivalent Si4- atoms to form AuSi4 tetrahedra that share corners with eight equivalent NpSi8 hexagonal bipyramids, corners with four equivalent AuSi4 tetrahedra, edges with four equivalent NpSi8 hexagonal bipyramids, and edges with four equivalent AuSi4 tetrahedra. All Au–Si bond lengths are 2.57 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Np7+, four equivalent Au+0.50+, and one Si4- atom. The Si–Si bond length is 2.27 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(SiPt)2 by Materials Project

Np(PtSi)2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Np4+ is bonded in a 8-coordinate geometry to eight Pt2- atoms. There are four shorter (3.22 Å) and four longer (3.28 Å) Np–Pt bond lengths. There are two inequivalent Pt2- sites. In the first Pt2- site, Pt2- is bonded in a 5-coordinate geometry to four equivalent Np4+ and five Si atoms. There are one shorter (2.40 Å) and four longer (2.43 Å) Pt–Si bond lengths. In the second Pt2- site, Pt2- is bonded to four equivalent Np4+ and four equivalent Si atoms to form a mixture of distorted edge and face-sharing PtNp4Si4 tetrahedra. All Pt–Si bond lengths are 2.50 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 5-coordinate geometry to five Pt2- atoms. In the second Si site, Si is bonded to four equivalent Pt2- atoms to form a mixture of edge and corner-sharing SiPt4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(FeSi)2 by Materials Project

Np(FeSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Np3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Np–Si bond lengths are 3.05 Å. Fe+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing FeSi4 tetrahedra. All Fe–Si bond lengths are 2.28 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Np3+, four equivalent Fe+2.50+, and one Si4- atom. The Si–Si bond length is 2.47 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(SiNi)2 by Materials Project

Np(NiSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Np4+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Np–Si bond lengths are 3.00 Å. Ni2+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing NiSi4 tetrahedra. All Ni–Si bond lengths are 2.31 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Np4+, four equivalent Ni2+, and one Si4- atom. The Si–Si bond length is 2.33 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(SeO3)2 by Materials Project

Np(SeO3)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Np4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Np–O bond distances ranging from 2.25–2.58 Å. There are two inequivalent Se4+ sites. In the first Se4+ site, Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.73–1.75 Å. In the second Se4+ site, Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.71–1.77 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Np4+ and one Se4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Np4+ and one Se4+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one Se4+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Np4+ and one Se4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Np4+ and one Se4+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Np4+ and one Se4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(SiOs)2 by Materials Project

Np(OsSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Np4+ is bonded in a 8-coordinate geometry to eight equivalent Os2- atoms. All Np–Os bond lengths are 3.17 Å. Os2- is bonded in a 4-coordinate geometry to four equivalent Np4+ and four equivalent Si atoms. All Os–Si bond lengths are 2.40 Å. Si is bonded in a 5-coordinate geometry to four equivalent Os2- and one Si atom. The Si–Si bond length is 2.35 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(SiPd)2 by Materials Project

Np(PdSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Np4+ is bonded to eight equivalent Si4- atoms to form NpSi8 hexagonal bipyramids that share corners with sixteen equivalent PdSi4 tetrahedra, edges with four equivalent NpSi8 hexagonal bipyramids, edges with eight equivalent PdSi4 tetrahedra, and faces with four equivalent NpSi8 hexagonal bipyramids. All Np–Si bond lengths are 3.11 Å. Pd2+ is bonded to four equivalent Si4- atoms to form PdSi4 tetrahedra that share corners with eight equivalent NpSi8 hexagonal bipyramids, corners with four equivalent PdSi4 tetrahedra, edges with four equivalent NpSi8 hexagonal bipyramids, and edges with four equivalent PdSi4 tetrahedra. All Pd–Si bond lengths are 2.49 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Np4+, four equivalent Pd2+, and one Si4- atom. The Si–Si bond length is 2.32 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(PS3)4 by Materials Project

Np(PS3)4 is I4/mcm-derived structured and crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. Np4+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (2.83 Å) and four longer (2.88 Å) Np–S bond lengths. P5+ is bonded to four S2- atoms to form edge-sharing PS4 tetrahedra. There are a spread of P–S bond distances ranging from 2.01–2.14 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted L-shaped geometry to one Np4+ and one P5+ atom. In the second S2- site, S2- is bonded in an L-shaped geometry to two equivalent P5+ atoms. In the third S2- site, S2- is bonded in a distorted L-shaped geometry to one Np4+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(MoO4)2 by Materials Project

Np(MoO4)2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Np4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Np–O bond distances ranging from 2.30–2.40 Å. There are two inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.79–1.82 Å. In the second Mo6+ site, Mo6+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.79 Å) and two longer (1.80 Å) Mo–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one Mo6+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one Mo6+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one Mo6+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Np4+ and one Mo6+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one Mo6+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one Mo6+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one Mo6+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one Mo6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(WO4)2 by Materials Project

Np(WO4)2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Np4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Np–O bond distances ranging from 2.30–2.41 Å. There are two inequivalent W6+ sites. In the first W6+ site, W6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of W–O bond distances ranging from 1.81–1.84 Å. In the second W6+ site, W6+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.81 Å) and two longer (1.82 Å) W–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one W6+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one W6+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one W6+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to one Np4+ and one W6+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Np4+ and one W6+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one W6+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one W6+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Np4+ and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Np(FeP3)4 by Materials Project

Np(FeP3)4 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. Np3+ is bonded to twelve equivalent P1- atoms to form NpP12 cuboctahedra that share faces with eight equivalent FeP6 octahedra. All Np–P bond lengths are 2.95 Å. Fe+2.25+ is bonded to six equivalent P1- atoms to form FeP6 octahedra that share corners with six equivalent FeP6 octahedra and faces with two equivalent NpP12 cuboctahedra. The corner-sharing octahedral tilt angles are 58°. All Fe–P bond lengths are 2.22 Å. P1- is bonded in a distorted bent 120 degrees geometry to one Np3+, two equivalent Fe+2.25+, and two equivalent P1- atoms. There are one shorter (2.34 Å) and one longer (2.35 Å) P–P bond lengths.

36 MATERIALS SCIENCE↗