RadEMSL

EMSL’s radiochemistry facility, RadEMSL, is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The facility 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. RadEMSL 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. RadEMSL users also have access to expert computational, modeling and simulation resources and support.

The facility provides 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 RadEMSL 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.

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

And don't miss the virtual tour of RadEMSL.

Additional Information:

Instruments

Highlighted Research Applications EMSL's Bruker wide-bore 750 MHz solids/liquids spectrometer is dedicated to radiological and environmental...
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
Housed in EMSL's RadEMSL (Radiochemistry Annex), the field emission electron microprobe (EMP) enables chemical analysis and imaging of radionuclides...
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
The environmental scanning electron microscope (ESEM) is a new-generation SEM that can image samples under controlled environments and temperatures...
Custodian(s): Bruce Arey, Scott Lea

Science Highlights

Posted: March 22, 2016
The Science A recent study examined in unprecedented detail the structural and thermodynamic properties of uranium (U(v)) containing compounds...
Posted: September 22, 2015
The Science Uranium dioxide (UO2) contains the less soluble and immobile form of uranium in nature, so it is the desired end product of...
Posted: July 31, 2015
Corrosion in uranium dioxide, a major component of fuel rods in nuclear reactors, causes the rods to expand creating problems during routine...
Posted: April 14, 2015
The Science Scientists found the incorporation of neptunium (V) (NpO2+, neptunyl) and uranium (VI) (UO22+, uranyl) in a variety of mineral...
Posted: July 06, 2011
Scientists from Pacific Northwest National Laboratory and Rai Enviro-Chem, LLC, recently published first-ever results that illustrate the importance...

Instruments

There are no related projects at this time.

EMSL’s radiochemistry facility, RadEMSL, is designed to accelerate scientific discovery and deepen the understanding of the chemical fate and transport of radionuclides in terrestrial and subsurface ecosystems.

The facility 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. RadEMSL 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. RadEMSL users also have access to expert computational, modeling and simulation resources and support.

The facility provides 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 RadEMSL 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.

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

And don't miss the virtual tour of RadEMSL.

Additional Information:

Ag Out-surface Diffusion In Crystalline SiC With An Effective SiO2 Diffusion Barrier.

Abstract: 

For applications of tristructural isotropic (TRISO) fuel particles in high temperature reactors, release of radioactive Ag isotope (110mAg) through the SiC coating layer is a safety concern. To understand the diffusion mechanism, Ag ion implantations near the surface and in the bulk were performed by utilizing different ion energies and energy-degrader foils. High temperature annealing was carried out on the as-irradiated samples to study the possible out-surface diffusion. Before and after annealing, Rutherford backscattering spectrometry (RBS) and secondary ion mass spectrometry (SIMS) measurements were employed to obtain the elemental profiles of the implanted samples. The results suggest little migration of buried Ag in the bulk, and an out-diffusion of the implanted Ag in the near-surface region of single crystal SiC. It is also found that a SiO2 layer, which was formed during annealing, may serve as an effective barrier to reduce or prevent Ag out diffusion through the SiC coating layer.

Citation: 
Xue H, HY Xiao, Z Zhu, V Shutthanandan, LL Snead, LA Boatner, WJ Weber, and Y Zhang.2015."Ag Out-surface Diffusion In Crystalline SiC With An Effective SiO2 Diffusion Barrier."Journal of Nuclear Materials 464:294-298. doi:10.1016/j.jnucmat.2015.05.001
Authors: 
Zhu Zihua
V Shutthanandan
Xue H
HY Xiao
Z Zhu
V Shutthanan
LL Snead
LA Boatner
WJ Weber
Y Zhang
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Publication year: 
2015

Soft Landing of Bare PtRu Nanoparticles for Electrochemical Reduction of Oxygen .

Abstract: 

Magnetron sputtering of two independent Pt and Ru targets coupled with inert gas aggregation in a modified commercial source has been combined with soft landing of mass-selected ions to prepare bare 4.5 nm diameter PtRu alloy nanoparticles on glassy carbon electrodes with controlled size and morphology for electrochemical reduction of oxygen in solution. Employing atomic force microscopy (AFM) it is shown that the nanoparticles bind randomly to the glassy carbon electrode at a relatively low coverage of 7 x 104 ions µm-2 and that their average height is centered at 4 nm. Scanning transmission electron microscopy images obtained in the high-angle annular dark field mode (STEM-HAADF) further confirm that the soft-landed PtRu alloy nanoparticles are uniform in size and have a Ru core decorated with small regions of Pt on the surface. Wide-area scans of the electrodes using X-ray photoelectron spectroscopy (XPS) reveal the presence of both Pt and Ru in relative atomic concentrations of ~9% and ~33%, respectively. Deconvolution of the high energy resolution XPS spectra in the Pt4f and Ru3d regions indicates the presence of both oxidized Pt and Ru. The substantially higher loading of Ru compared to Pt and enrichment of Pt at the surface of the alloy nanoparticles is confirmed by wide-area analysis of the electrodes using time-of-flight medium energy ion scattering (TOF-MEIS) employing both 80 keV He+ and O+ ions. The activity of electrodes containing 7 x 104 ions µm-2 of bare 4.5 nm PtRu nanoparticles toward the electrochemical reduction of oxygen was evaluated employing cyclic voltammetry (CV) in 0.1 M HClO4 and 0.5 M H2SO4 solutions. In both electrolytes a pronounced reduction peak was observed during O2 purging of the solution that was not evident during purging with Ar. Repeated electrochemical cycling of the electrodes revealed little evolution in the shape or position of the voltammograms indicating high stability of the alloy nanoparticles supported on glassy carbon. The reproducibility of the nanoparticle synthesis and deposition was evaluated by employing the same experimental parameters to prepare nanoparticles on glassy carbon electrodes on three occasions separated by several days. Surfaces with almost identical electrochemical behavior were observed with CV, demonstrating the highly reproducible preparation of bare alloy nanoparticles using physical synthesis in the gas-phase combined with soft landing of mass-selected ions

Citation: 
Johnson GE, RJ Colby, MH Engelhard, DW Moon, and J Laskin.2015."Soft Landing of Bare PtRu Nanoparticles for Electrochemical Reduction of Oxygen ."Nanoscale 7(29):12379-12391. doi:10.1039/C5NR03154K
Authors: 
H Mark
Julia Laskin
Johnson GE
RJ Colby
MH Engelhard
DW Moon
J Laskin
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Volume: 
7
Issue: 
29
Pages: 
12379-12391
Publication year: 
2015

Chemical expansion affected oxygen vacancy stability in different oxide structures from first principles calculations.

Abstract: 

We study the chemical expansion for neutral and charged oxygen vacancies in fluorite, rocksalt, perovskite and pyrochlores materials using first principles calculations. We show that the neutral oxygen vacancy leads to lattice expansion whereas the charged vacancy leads to lattice contraction. In addition, we show that there is a window of strain within which an oxygen vacancy is stable; beyond that range, the vacancy can become unstable. Using CeO2|ZrO2 interface structure as an example, we show that the concentration of oxygen vacancies can be manipulated via strain, and the vacancies can be preferentially stabilized. These results could serve as guiding principles in predicting oxygen vacancy stability in strained systems and in the design of vacancy stabilized materials.

Citation: 
Aidhy DS, B Liu, Y Zhang, and WJ Weber.2015."Chemical expansion affected oxygen vacancy stability in different oxide structures from first principles calculations."Computational Materials Science 99:298-305. doi:doi:10.1016/j.commatsci.2014.12.030
Authors: 
DS Aidhy
B Liu
Y Zhang
WJ Weber
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Publication year: 
2015

Damage Processes In MgO Irradiated With Medium-energy Heavy Ions.

Abstract: 

The micro-structural modifications produced in MgO single crystals exposed to medium-energy heavy ions (1.2-MeV Au) were investigated using Rutherford backscattering spectrometry in channeling geometry coupled to Monte-Carlo analyses, secondary ion mass spectrometry, X-ray diffraction and transmission electron microscopy. The damage accumulation and the elastic strain variation were interpreted in the framework of the multi-step damage accumulation (MSDA) model. Both build-ups follow a multi-step process similar to that recently observed for ion-irradiated yttria-stabilized zirconia (YSZ) single crystals. However, in MgO, an unexpectedly high disorder level occurs far beyond the theoretical damage distribution. These results strongly suggest that the migration of defects created in the near-surface layer is most likely at the origin of the broadening of the damage depth distribution in MgO.

Citation: 
Moll SJ, Y Zhang, A Debelle, L Thome, JP Crocombette, Z Zhu, J Jagielski, and WJ Weber.2015."Damage Processes In MgO Irradiated With Medium-energy Heavy Ions."Acta Materialia 88:314-322. doi:10.1016/j.actamat.2015.01.011
Authors: 
Zhu Zihua
Moll SJ
Y Zhang
A Debelle
L Thome
JP Crocombette
Z Zhu
J Jagielski
WJ Weber
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2015

Gas-Phase Fragmentation Pathways of Mixed-Addenda Keggin Anions: PMo12-nWnO403- (n = 0-12).

Abstract: 

We report a collision-induced dissociation (CID) investigation of the mixed addenda polyoxometalate (POM) anions, PMo12-nWnO403- (n = 0-12). The anions were generated in solution using a straightforward single-step synthesis approach and introduced into the gas phase by electrospray ionization (ESI). Distinct differences in fragmentation patterns were observed for the range of mixed POMs examined in this study. CID of molybdenum-rich anions, PMo12- nWnO403- (n = 0-2), generates an abundant doubly charged fragment containing seven metal atoms (M) and twenty-two oxygen atoms (M7O222-) and its complementary singly charged PM5O18- ion, while the Lindqvist anion, (M6O192-) and its complementary PM6O21- ion are the dominant fragments of Keggin POMs containing more than two tungsten atoms, PMo12-nWnO403- (n = 3-12). The observed transition in the dissociation pathways with an increase in the number of W atoms may be attributed to the higher stability of tungsten-rich anions towards isomerization. We find that the observed distribution of Mo and W atoms in the major M6O192- and M7O222- fragment ions is different from that predicted by a random distribution indicating substantial segregation of the addenda metal atoms in the POMs. Electron detachment from the triply charged precursor anion resulting in formation of doubly charged anions is observed. This is a dominant dissociation pathway for mixed POMs having a majority (8-11) of W atoms and a minor channel for other precursors indicating a close competition between fragmentation and electron detachment pathways of POM anions.

Citation: 
Gunaratne KDD, V Prabhakaran, GE Johnson, and J Laskin.2015."Gas-Phase Fragmentation Pathways of Mixed-Addenda Keggin Anions: PMo12-nWnO403- (n = 0-12)."Journal of the American Society for Mass Spectrometry 26(6):1027-1035. doi:10.1007/s13361-015-1090-5
Authors: 
Laskin Julia
Gunaratne KDD
V Prabhakaran
GE Johnson
J Laskin
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Volume: 
26
Issue: 
6
Pages: 
1027-1035
Publication year: 
2015

Coexistence of Epitaxial Lattice Rotation and Twinning Tilt Induced by Surface Symmetrymismatch.

Abstract: 

Combined x-ray diffraction and first-principles studies of various epitaxial rutile-type metal dioxide films on Al2O3(0001) substrates reveal an unexpected rectangle-on-parallelogram heteroepitaxy. Unique matching of particular lattice spacings and crystal angles between the oxygen sublattices of Al2O3(0001) and the film(100) result in coexisted crystal rotation and lattice twinning inside the film. We demonstrate that, besides symmetry and lattice mismatch, angular mismatch along a specific crystal direction is also an important factor determining epitaxy. A generalized theorem has been proposed to explain epitaxial behaviors for tetragonal metal dioxides on Al2O3(0001).

Citation: 
Qiao L, HY Xiao, WJ Weber, and MD Biegalski.2014."Coexistence of Epitaxial Lattice Rotation and Twinning Tilt Induced by Surface Symmetrymismatch."Applied Physics Letters 104(22):221602. doi:10.1063/1.4881612
Authors: 
L Qiao
HY Xiao
WJ Weber
MD Biegalski
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2014

Ion-Surface Collisions in Mass Spectrometry: Where Analytical Chemistry Meets Surface Science.

Abstract: 

This article presents a personal perspective regarding the development of key concepts in understanding hyperthermal collisions of polyatomic ions with surfaces as a unique tool for mass spectrometry applications. In particular, this article provides a historic overview of studies focused on understanding the phenomena underlying surface-induced dissociation (SID) and mass-selected deposition of complex ions on surfaces. Fast energy transfer in ion-surface collisions makes SID especially advantageous for structural characterization of large complex molecules, such as peptides, proteins, and protein complexes. Soft, dissociative, and reactive landing of mass-selected ions provide the basis for preparatory mass spectrometry. These techniques enable precisely controlled deposition of ions on surfaces for a variety of applications. This perspective article shows how basic concepts developed in the 1920s and 1970s have evolved to advance promising mass-spectrometry-based applications.

Citation: 
Laskin J.2015."Ion-Surface Collisions in Mass Spectrometry: Where Analytical Chemistry Meets Surface Science."International Journal of Mass Spectrometry 377:188-200. doi:10.1016/j.ijms.2014.07.004
Authors: 
J Laskin
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Publication year: 
2015

Soft Landing of Mass-Selected Gold Clusters: Influence of Ion and Ligand on Charge Retention and Reactivity .

Abstract: 

Herein, we employ a combination of reduction synthesis in solution, soft landing of mass-selected precursor and product ions, and in situ time-of-flight secondary ion mass spectrometry (TOF-SIMS) to examine the influence of ion and the length of diphosphine ligands on the charge retention and reactivity of ligated gold clusters deposited onto self-assembled monolayer surfaces (SAMs). Product ions (Au10L42+, (10,4)2+, L = 1,3-bis(diphenyl-phosphino)propane, DPPP) were prepared through in-source collision induced dissociation (CID) and precursor ions [(8,4)2+, L = 1,6-bis(diphenylphosphino)hexane, DPPH] were synthesized in solution for comparison to (11,5)3+ precursor ions ligated with DPPP investigated previously (ACS Nano 2012, 6, 573 and J. Phys. Chem. C. 2012, 116, 24977). Similar to (11,5)3+ precursor ions, the (10,4)2+ product ions are shown to retain charge on 1H,1H,2H,2H-perfluorodecanethiol monolayers (FSAMs). Additional abundant peaks at higher m/z indicative of reactivity are observed in the TOF-SIMS spectrum of (10,4)2+ product ions that are not seen for (11,5)3+ precursor ions. The abundance of (10,4)2+ on 16-mercaptohexadecanoic acid (COOH-SAMs) is demonstrated to be lower than on FSAMs, consistent with partial reduction of charge. The (10,4)2+ product ion on 1-dodecanethiol (HSAMs) exhibits peaks similar to those seen on the COOH-SAM. On the HSAM, higher m/z peaks indicative of reactivity are observed similar to those on the FSAM. The (8,4)2+ DPPH precursor ions are shown to retain charge on FSAMs similar to (11,5)3+ precursor ions prepared with DPPP. An additional peak corresponding to attachment of one gold atom to (8,4)2+ is observed at higher m/z for DPPH-ligated clusters. On the COOH-SAM, (8,4)2+ is less abundant than on the FSAM consistent with partial neutralization. The results indicate that although retention of charge by product ions generated by CID is similar to precursor ions their reactivity during analysis with SIMS is different resulting in the formation of peaks corresponding to reaction products. The length of the ligand exerts only a minor influence on the charge retention and reactivity of gold clusters. Based on the observed reactivity of (10,4)2+ it is anticipated that in-source CID will be increasingly applied for the preparation of a distribution of product ions, including undercoordinated and reactive species, for soft landing onto surfaces.

Citation: 
Johnson GE, and J Laskin.2015."Soft Landing of Mass-Selected Gold Clusters: Influence of Ion and Ligand on Charge Retention and Reactivity ."International Journal of Mass Spectrometry 377:205-213. doi:10.1016/j.ijms.2014.05.013
Authors: 
Laskin Julia
Johnson GE
J Laskin
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Publication year: 
2015

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