Radiochemistry Annex

EMSL’s Radiochemistry Annex is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The annex offers experimental and computational tools uniquely suited for actinide chemistry studies. The spectroscopic and imaging instruments at this facility are ideally designed for the study of contaminated environmental materials, examination of radionuclide speciation and detection of chemical signatures. The annex houses nuclear magnetic resonance instruments and surface science capabilities, such as X-ray photoelectron spectroscopy, electron microscopy, electron microprobe, transmission electron microscopy and scanning electron microscopy. Annex users also have access to expert computational, modeling and simulation resources and support.

The annex is an environment where multiple experimental approaches are encouraged. Investigating problems at an integrated, cross-disciplinary level encourages holistic understanding, which ultimately provides policy makers the information they need to make sound remediation choices.

Like all of EMSL's capabilities, those housed in the annex are available to the scientific community at typically no cost for openly published research. Scientists gain access to instruments and collaborate with onsite microscopy experts through a peer-reviewed proposal process. Research conducted in the annex requires special information and handling. Prior to submitting a proposal, potential users should familiarize themselves with the guidance for using and shipping radioactive material to the annex.

Radiochemistry Annex videos on EMSL's YouTube channel - Learn about the individual instruments in the Radiochemistry Annex and specifically how they advance subsurface and terrestrial ecosystem science.

And don't miss the virtual tour of our Radiochemistry Annex.

Additional Information:

Instruments

Housed in EMSL's Radiochemistry Annex, the field emission electron microprobe (EMP) enables chemical analysis and imaging of radionuclides with high...
Custodian(s): Bruce Arey
EMSL's Digital Instruments Radiological BioScope™ Atomic Force Microscope (AFM) allows radiological samples to be examined in fluids or air with...
Custodian(s): Kevin M. Rosso
Research applications Samples containing paramagnetics Soils (SOM and NOM) Metal oxide materials for catalysis applications Researchers may operate...
Custodian(s): Nancy Washton, Sarah D Burton
EMSL's Bruker wide-bore 750 MHz solids/liquids/imaging spectrometer is dedicated to radiological and environmental samples. Housed in the EMSL...
Custodian(s): Nancy Washton
The Bruker EMX electron paramagnetic resonance (EPR) spectrometer performs continuous-wave magnetic resonance using electron spins to selectively...
Custodian(s): Eric Walter

Science Highlights

Posted: July 06, 2011
Scientists from Pacific Northwest National Laboratory and Rai Enviro-Chem, LLC, recently published first-ever results that illustrate the importance...

EMSL’s Radiochemistry Annex is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The annex offers experimental and computational tools uniquely suited for actinide chemistry studies. The spectroscopic and imaging instruments at this facility are ideally designed for the study of contaminated environmental materials, examination of radionuclide speciation and detection of chemical signatures. The annex houses nuclear magnetic resonance instruments and surface science capabilities, such as X-ray photoelectron spectroscopy, electron microscopy, electron microprobe, transmission electron microscopy and scanning electron microscopy. Annex users also have access to expert computational, modeling and simulation resources and support.

The annex is an environment where multiple experimental approaches are encouraged. Investigating problems at an integrated, cross-disciplinary level encourages holistic understanding, which ultimately provides policy makers the information they need to make sound remediation choices.

Like all of EMSL's capabilities, those housed in the annex are available to the scientific community at typically no cost for openly published research. Scientists gain access to instruments and collaborate with onsite microscopy experts through a peer-reviewed proposal process. Research conducted in the annex requires special information and handling. Prior to submitting a proposal, potential users should familiarize themselves with the guidance for using and shipping radioactive material to the annex.

Radiochemistry Annex videos on EMSL's YouTube channel - Learn about the individual instruments in the Radiochemistry Annex and specifically how they advance subsurface and terrestrial ecosystem science.

And don't miss the virtual tour of our Radiochemistry Annex.

Additional Information:

Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations.

Abstract: 

The altered layer (i.e., amorphous hydrated surface layer and crystalline reaction products)represents a complex region, both physically and chemically, sandwiched between two distinct boundaries - pristine glass surface at the inner most interface and aqueous solution at the outer most. The physico-chemical processes that control the development of this region have a significant impact on the long-term glass-water reaction. Computational models, spanning different length and time-scales, are currently being developed to improve our understanding of this complex and dynamic process with the goal of accurately describing the pore-scale changes that occur as the system evolves. These modeling approaches include Geochemical Reaction Path simulations, Glass Reactivity in Allowance for Alteration Layer simulations, Monte Carlo simulations, and Molecular Dynamics methods. Discussed in this manuscript are the advances and limitations of each modeling approach placed in the context of the glass water reaction and how collectively these approaches provide insights into the mechanisms that control the formation and evolution of altered layers; thus providing the fundamental data needed to develop pore-scale equations that enable more accurate predictions of nuclear waste glass corrosion in a geologic repository.

Citation: 
Pierce EM, P Frugier, LJ Criscenti, KD Kwon, and SN Kerisit.2014."Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations."International Journal of Applied Glass Science 5(4):421-435. doi:10.1111/ijag.12077
Authors: 
EM Pierce
P Frugier
LJ Criscenti
KD Kwon
SN Kerisit
Volume: 
5
Issue: 
4
Pages: 
421-435
Publication year: 
2014

Reflection High-Energy Electron Diffraction Beam-Induced Structural and Property Changes on WO3 Thin Films.

Abstract: 

Reduction of transition metal oxides can greatly change their physical and chemical properties. Using deposition of WO3 as a case study, we demonstrate that reflection high-energy electron diffraction (RHEED), a surface-sensitive tool widely used to monitor thin-film deposition processes, can significantly affect the cation valence and physical properties of the films through electron-beam induced sample reduction. The RHEED beam is found to increase film smoothness during epitaxial growth of WO3, as well as change the electronic properties of the film through preferential removal of surface oxygen.

Citation: 
Du Y, H Zhang, T Varga, and SA Chambers.2014."Reflection High-Energy Electron Diffraction Beam-Induced Structural and Property Changes on WO3 Thin Films."Applied Physics Letters 105(5):051606. doi:10.1063/1.4892810
Authors: 
Du Y
H Zhang
T Varga
SA Chambers
Volume: 
Issue: 
Pages: 
Publication year: 
2014

Strong Room-temperature Negative Transconductance In An Axial Si/Ge Hetero-nanowire Tunneling Field-effect Transistor.

Abstract: 

We report on room-temperature negative transconductance (NTC) in axial Si/Ge hetero-nanowire tunneling field-effect transistors (TFETs). The NTC produces a current peak-to-valley ratio > 45, a high value for a Si-based device. We characterize the NTC characteristics over a range of gate VG and drain VD voltages, finding that NTC persists down to VD = –50 mV. The physical mechanism responsible for the NTC is the VG-induced depletion in the p-Ge section that eventually reduces the maximum electric field that triggers the tunneling ID, as confirmed via three-dimensional TCAD simulations.

Citation: 
Zhang P, ST Le, X Hou, A Zaslavsky, DE Perea, SA Dayeh, and ST Picraux.2014."Strong Room-temperature Negative Transconductance In An Axial Si/Ge Hetero-nanowire Tunneling Field-effect Transistor."Applied Physics Letters 105(6):Article No. 062106. doi:10.1063/1.4892950
Authors: 
P Zhang
ST Le
X Hou
A Zaslavsky
DE Perea
SA Dayeh
ST Picraux
Instruments: 
Volume: 
Issue: 
Pages: 
Publication year: 
2014

In-situ Study of Nanostructure and Electrical Resistance of Nanocluster Films Irradiated with Ion Beams.

Abstract: 

An in-situ study is reported on the structural evolution in nanocluster films under He+ ion irradiation using an advanced helium ion microscope. The films consist of loosely interconnected nanoclusters of magnetite or iron-magnetite (Fe-Fe3O4) core-shells. The nanostructure is observed to undergo dramatic changes under ion-beam irradiation, featuring grain growth, phase transition, particle aggregation, and formation of nanowire-like network and nano-pores. Studies based on ion irradiation, thermal annealing and election irradiation have indicated that the major structural evolution is activated by elastic nuclear collisions, while both electronic and thermal processes can play a significant role once the evolution starts. The electrical resistance of the Fe-Fe3O4 films measured in situ exhibits a super-exponential decay with dose. The behavior suggests that the nanocluster films possess an intrinsic merit for development of an advanced online monitor for neutron radiation with both high detection sensitivity and long-term applicability, which can enhance safety measures in many nuclear operations.

Citation: 
Jiang W, JA Sundararajan, T Varga, ME Bowden, Y Qiang, JS McCloy, CH Henager, Jr, and RO Montgomery.2014."In-situ Study of Nanostructure and Electrical Resistance of Nanocluster Films Irradiated with Ion Beams."Advanced Functional Materials 24(39):6210-6218. doi:10.1002/adfm.201400553
Authors: 
W Jiang
JA Sundararajan
T Varga
ME Bowden
Y Qiang
JS McCloy
CH Henager
Jr
RO Montgomery
Instruments: 
Volume: 
24
Issue: 
39
Pages: 
6210-6218
Publication year: 
2014

Characterization of Defects in N-type 4H-SiC After High-Energy N Ion Implantation by RBS-Channeling and Raman Spectroscopy.

Abstract: 

Implantation with 1 MeV N ions was performed at room temperature in n-type 4H-SiC(0001) to four implantation fluences (or doses in dpa (displacements per atom) at the damage peak) of 1.5×1013(0.0034), 7.8×1013(0.018), 1.5×1014(0.034), and 7.8×1014(0.18) ions/cm2, respectively. The evolution of disorder was studied using Rutherford backscattering spectrometry in channeling mode (RBS-C) and Raman spectroscopy. The disorder in the Si sub-lattice was found to be less than 10% for the dpa of 0.0034 and 0.0178 and increased to 40% and 60% for the dpa of 0.034 and 0.178 respectively. Raman Spectroscopy was performed using a green laser of wavelength 532 nm as excitation source. The normalized Raman Intensity, In shows disorder of 41%, 69%, 77% and 100% for the dpa of 0.0034, 0.017, 0.034 and 0.178 respectively. In this paper, the characterizations of the defects produced due to the Nitrogen implantation in 4H-SiC are presented and the results are discussed.

Citation: 
Kummari VC, T Reinert, W Jiang, FD McDaniel, and B Rout.2014."Characterization of Defects in N-type 4H-SiC After High-Energy N Ion Implantation by RBS-Channeling and Raman Spectroscopy."Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms 332:28-32. doi:10.1016/j.nimb.2014.02.023
Authors: 
VC Kummari
T Reinert
W Jiang
FD McDaniel
B Rout
Instruments: 
Volume: 
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Publication year: 
2014

Nature of Nano-Sized Plutonium Particles in Soils at the Hanford Site.

Abstract: 

The occurrence of plutonium dioxide (PuO2) either from direct deposition or from the precipitation of plutonium-bearing solutions in contaminated soils and sediments has been well described, particularly for the Hanford site in Washington State. However, past research has suggested that plutonium may exist in environmental samples at the Hanford site in chemical forms in addition to large size PuO2 particles and that these previously unidentified nano-sized particles maybe more reactive and thus more likely to influence the environmental mobility of Pu. Here we present evidence for the formation of nano-sized plutonium iron phosphate hydroxide structurally related to the rhabdophane group nanoparticles in 216-Z9 crib sediments from Hanford using transmission electron microscopy (TEM). The distribution and nature of these nanoparticles varied depending on the adjacent phases present. Fine electron probes were used to obtain electron diffraction and electron energy-loss spectra from specific phase regions of the 216-Z9 cribs specimens from fine-grained plutonium oxide and phosphate phases. Energy-loss spectra were used to evaluate the plutonium N4,5 (4d → 5f ) and iron L2,3 absorption edges. The iron plutonium phosphate formation may depend on the local micro-environment in the sediments, availability of phosphate, and hence the distribution of these minerals may control long-term migration of Pu in the soil. This study also points to the utility of using electron beam methods for determining the identity of actinide phases and their association with other sediment phases.

Citation: 
Buck EC, DA Moore, KR Czerwinski, SD Conradson, O Batuk, and AR Felmy.2014."Nature of Nano-Sized Plutonium Particles in Soils at the Hanford Site."Radiochimica Acta 102(12):1059-1068. doi:10.1515/ract-2013-2103
Authors: 
EC Buck
DA Moore
KR Czerwinski
SD Conradson
O Batuk
AR Felmy
Volume: 
102
Issue: 
12
Pages: 
1059-1068
Publication year: 
2014

Excited States and Luminescent Properties of UO2F2 and Its Solvated Complexes in Aqueous Solution.

Abstract: 

The electronic absorption and emission spectra of free UO2F2 and its water solvated complexes below 32,000 cm1 are investigated at the levels of ab initio CASPT2 and CCSD(T) with inclusion of scalar relativistic and spin-orbit coupling effects. The influence of the water coordination on the electronic spectra of UO2F2 is explored by investigating the excited states of solvated complexes (H2O)nUO2F2 (n = 13). In these uranyl-complexes, water coordination is found to have appreciable influence on the 3 ( = 1g) character of the luminescent state and on the electronic spectral shape. The simulated luminescence spectral curves based on the calculated spectral parameters of (H2O)nUO2F2 from CCSD(T) approach agree well with experimental spectra in aqueous solution at both near liquid helium temperature and room temperature. The possible luminescence spectra of free UO2F2 in gas phase are predicted based on CASPT2 and CCSD(T) results, respectively, by considering three symmetric vibration modes. The effect of competition between spin-orbital coupling and ligand field repulsion on the luminescent state properties is discussed.

Citation: 
Su J, Z Wang, D Pan, and J Li.2014."Excited States and Luminescent Properties of UO2F2 and Its Solvated Complexes in Aqueous Solution."Inorganic Chemistry 53(14):7340-7350. doi:10.1021/ic5006852
Authors: 
Su J
Z Wang
D Pan
J Li
Volume: 
53
Issue: 
14
Pages: 
7340-7350
Publication year: 
2014

Reversible nano-structuring of SrCrO3-δ through oxidization and reduction at low temperatures.

Abstract: 

Oxygen vacancies are often present in complex oxides as point defects and their effect on the electronic properties of the oxides is typically uniform and isotropic. Exploiting oxygen deficiency in order to generate controllably, novel structures and functional properties remains a challenging goal. We show that epitaxial strontium chromite films can be transformed, reversibly and at low temperature, from the cubic metallic perovskite SrCrO3-δ to the rhombohedral semiconducting SrCrO2.8. Oxygen vacancies aggregate and give rise to ordered arrays of {111}-oriented SrO2 planes interleaved between layers of tetrahedrally-coordinated Cr4+ and separated by ~1 nm. First-principle calculations provide insight into the origin of the stability of such nanostructures and, consistent with the experimental data, predict that the barrier for oxide ion diffusion along these quasi-2D nanostructures is ~5 times lower than that in the cubic SrCrO3-δ – a property of considerable importance in, for example, solid oxide fuel cells.

Citation: 
Zhang H, P Sushko, RJ Colby, Y Du, ME Bowden, and SA Chambers.2014."Reversible nano-structuring of SrCrO3-? through oxidization and reduction at low temperatures."Nature Communications 5:Artcle No. 4669. doi:10.1038/ncomms5669
Authors: 
H Zhang
P Sushko
RJ Colby
Y Du
ME Bowden
SA Chambers
Volume: 
Issue: 
Pages: 
Publication year: 
2014

Synthesis and Evaluation of Cu/SAPO-34 Catalysts for NH3-SCR 2: Solid-state Ion Exchange and One-pot Synthesis.

Abstract: 

Cu-SAPO-34 catalysts are synthesized using two methods: solid-state ion exchange (SSIE) and one-pot synthesis. SSIE is conducted by calcining SAPO-34/CuO mixtures at elevated temperatures. For the one-pot synthesis method, Cu-containing chemicals (CuO and CuSO4) are added during gel preparation. A high-temperature calcination step is also needed for this method. Catalysts are characterized with surface area/pore volume measurements, temperature programmed reduction (TPR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies, and scanning electron microscopy (SEM). Catalytic properties are examined using standard ammonia selective catalytic reduction (NH3-SCR) and ammonia oxidation reactions. In Cu-SAPO-34 samples formed using SSIE, Cu presents both as isolated Cu2+ ions and unreacted CuO. The former is highly active and selective in NH3-SCR, while the latter catalyzes a side reaction; notably, the non-selective oxidation of NH3 above 350 ºC. Using the one-pot method followed by a high-temperature aging treatment, it is possible to form Cu SAPO-34 samples with predominately isolated Cu2+ ions at low Cu loadings. However at much higher Cu loadings, isolated Cu2+ ions that bind weakly with the CHA framework and CuO clusters also form. These Cu moieties are very active in catalyzing non-selective NH3 oxidation above 350 ºC. Low-temperature reaction kinetics indicate that Cu-SAPO-34 samples formed using SSIE have core-shell structures where Cu is enriched in the shell layers; while Cu is more evenly distributed within the one-pot samples. Reaction kinetics also suggest that at low temperatures, the local environment next to Cu2+ ion centers plays little role on the overall catalytic properties. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle under contract number DE-AC05-76RL01830. The authors also thank Shari Li (PNNL) for surface area/pore volume measurements, and Bruce W. Arey (PNNL) for SEM measurements. Discussions with Drs. A. Yezerets, K. Kamasamudram, J.H. Li, N. Currier and J.Y. Luo from Cummins, Inc. and H.Y. Chen and H. Hess from Johnson-Matthey are greatly appreciated.

Citation: 
Gao F, ED Walter, NM Washton, J Szanyi, and CHF Peden.2015."Synthesis and Evaluation of Cu/SAPO-34 Catalysts for NH3-SCR 2: Solid-state Ion Exchange and One-pot Synthesis."Applied Catalysis. B, Environmental 162:501-514. doi:10.1016/j.apcatb.2014.07.029
Authors: 
F Gao
ED Walter
NM Washton
J Szanyi
CHF Peden
Volume: 
Issue: 
Pages: 
Publication year: 
2015

Strain Accommodation By Facile WO6 Octahedral Distortion and Tilting During WO3 Heteroepitaxy on SrTiO3(001).

Abstract: 

In this paper, we show that compared to other BO6 octahedra in ABO3 structured perovskite oxides, the WO6 octahedra in tungsten trioxide (WO3) can withstand a much larger degree of distortion and tilting to accommodate interfacial strain, which in turn strongly impact the nucleation, structure, and defect formation during the epitaxial growth of WO3 on SrTiO3(001). A meta-stable tetragonal phase can be stabilized by epitaxy and a thickness dependent phase transition (tetragonal to monoclinic) is observed. In contrast to misfit dislocations to accommodate the interfacial stain, the facial WO6 octahedral distortion and tilting give rise to three types of planar defects that affect more than 15 monolayers from the interface. These atomically resolved, unusual interfacial defects may significantly alter the electronic, electrochromic, and mechanical properties of the epitaxial films.

Citation: 
Du Y, M Gu, T Varga, CM Wang, ME Bowden, and SA Chambers.2014."Strain Accommodation By Facile WO6 Octahedral Distortion and Tilting During WO3 Heteroepitaxy on SrTiO3(001)."ACS Applied Materials & Interfaces 6(16):14253-14258. doi:10.1021/am5035686
Authors: 
Du Y
M Gu
T Varga
CM Wang
ME Bowden
SA Chambers
Volume: 
6
Issue: 
16
Pages: 
14253-14258
Publication year: 
2014

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