Search results for: Lav Tandon

Items from 1 to 20 out of 25 results

article

Analytical chemistry of nuclear material: case studies from Los Alamos National Laboratory

Justin N. Cross, Kevin J. Kuhn, David J. Kunsberg, John H. Matonic, more

Journal of Radioanalytical and Nuclear Chemistry > 2018 > 318 > 3 > 1697-1712

Presented here are three case studies that demonstrate the breadth of bulk actinide analytical chemistry at Los Alamos National Laboratory (LANL). This laboratory was established during the Manhattan Project and is still considered one of the premier analytical laboratories for special nuclear materials characterization around the globe. First, the analytical chemistry of ²³⁸Pu is presented, showcasing...

article

The application of radiochronometry during the 4th collaborative materials exercise of the nuclear forensics international technical working group (ITWG)

Michael J. Kristo, Ross Williams, Amy M. Gaffney, Theresa M. Kayzar-Boggs, more

Journal of Radioanalytical and Nuclear Chemistry > 2018 > 315 > 2 > 425-434

In a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on three low enriched uranium oxide samples, providing 12 analytical results using three different parent-daughter pairs serving as independent chronometers. The vast majority of the results were consistent with one another and consistent with the known processing history of...

article

Uranium assay and trace element analysis of the fourth collaborative material exercise samples by the modified Davies-Gray method and the ICP-MS/OES techniques

Aubrey N. Nelwamondo, Lisa P. Colletti, Rachel E. Lindvall, Anna Vesterlund, more

Journal of Radioanalytical and Nuclear Chemistry > 2018 > 315 > 2 > 379-394

An international group of laboratories participating in CMX-4 subjected three samples to comparative nuclear forensic analysis using uranium assay and trace element analysis techniques to determine if the samples had similar or different origins. Uranium assay indicated that two pellet samples (ES-2 and ES-3) were nearly pure UO₂ while the black powder sample ES-1 was primarily UO₂ with UO₃ and/or...

article

Determination of origin and intended use of plutonium metal using nuclear forensic techniques

Jung H. Rim, Kevin J. Kuhn, Lav Tandon, Ning Xu, more

Forensic Science International > 2017 > 273 > C > e1-e9

Nuclear forensics techniques, including micro-XRF, gamma spectrometry, trace elemental analysis and isotopic/chronometric characterization were used to interrogate two, potentially related plutonium metal foils. These samples were submitted for analysis with only limited production information, and a comprehensive suite of forensic analyses were performed. Resulting analytical data was paired with...

article

Chemical investigation of three plutonium–beryllium neutron sources

Benjamin Byerly, Kevin Kuhn, Lisa Colletti, Lynn Foster, more

Journal of Radioanalytical and Nuclear Chemistry > 2017 > 312 > 1 > 95-104

Thorough physical and chemical characterization of plutonium–beryllium (PuBe) neutron sources is an important capability with applications ranging from material accountancy to nuclear forensics. Characterization of PuBe sources is not trivial owing to range of existing source designs and the need for adequate infrastructure to deal with radiation and protect the analyst. This study demonstrates a...

article

Nuclear forensic analysis of a non-traditional actinide sample

Jamie L. Doyle, Kevin Kuhn, Benjamin Byerly, Lisa Colletti, more

Talanta > 2016 > 159 > C > 200-207

Nuclear forensic publications, performance tests, and research and development efforts typically target the bulk global inventory of intentionally safeguarded materials, such as plutonium (Pu) and uranium (U). Other materials, such as neptunium (Np), pose a nuclear security risk as well. Trafficking leading to recovery of an interdicted Np sample is a realistic concern especially for materials originating...

article

Forensic investigation of plutonium metal: a case study of CRM 126

Benjamin L. Byerly, Floyd Stanley, Khal Spencer, Lisa Colletti, more

Journal of Radioanalytical and Nuclear Chemistry > 2016 > 310 > 2 > 623-632

In this study, a certified plutonium metal reference material (CRM 126) with a known production history is examined using analytical methods that are commonly employed in nuclear forensics for provenancing and attribution. The measured plutonium isotopic composition and actinide assay are consistent with values reported on the reference material certificate. Model ages from U/Pu and Am/Pu chronometers...

article

Plutonium oxalate precipitation for trace elemental determination in plutonium materials

Ning Xu, David Gallimore, Elmer Lujan, Katherine Garduno, more

Journal of Radioanalytical and Nuclear Chemistry > 2016 > 307 > 2 > 1203-1213

An analytical chemistry method has been developed that removes the plutonium (Pu) matrix from the dissolved Pu metal or oxide solution prior to the determination of trace impurities that are present in the metal or oxide. In this study, a Pu oxalate approach was employed to separate Pu from trace impurities. After Pu(III) was precipitated with oxalic acid and separated by centrifugation, trace elemental...

article

A lexicon for consistent description of material images for nuclear forensics

Alison L. Tamasi, Leigh J. Cash, Christopher Eley, Reid B. Porter, more

Journal of Radioanalytical and Nuclear Chemistry > 2016 > 307 > 3 > 1611-1619

We have developed a lexicon to consistently and objectively describe morphological features observed in scanning electron microscopy (SEM) images. Here we provide the lexicon flowsheet, define the terminology, and detail step-by-step characterization of SEM images collected from a set of actinide oxides. We conclude that this lexicon can be used to characterize texture and surface features, particle...

article

Determination of initial fuel state and number of reactor shutdowns in archived low-burnup uranium targets

Benjamin Byerly, Lav Tandon, Anna Hayes-Sterbenz, Patrick Martinez, more

Journal of Radioanalytical and Nuclear Chemistry > 2016 > 307 > 3 > 1871-1876

This study presents a method for destructive analysis of irradiated uranium (U) targets, with a focus on collection and measurement of long-lived (t _1/2 > ~10 years) and stable fission product isotopes of ruthenium and cesium. Long-lived and stable isotopes of these elements can provide information on reactor conditions (e.g. flux, irradiation time, cooling time) in old samples (>5–10 years)...

article

Dissolution of aerosol particles collected from nuclear facility plutonium production process

Ning Xu, Alex Martinez, Michael Schappert, Dennis P. Montoya, more

Journal of Radioanalytical and Nuclear Chemistry > 2016 > 307 > 3 > 2047-2053

A simple, robust analytical chemistry method has been developed to dissolve plutonium containing particles in a complex matrix. The aerosol particles collected on Marple cascade impactor substrates were shown to be dissolved completely with an acid mixture of 12 M HNO₃ and 0.1 M HF. A pressurized closed vessel acid digestion technique was utilized to heat the samples at 130 °C for 16 h to facilitate...

article

The urgent requirement for new radioanalytical certified reference materials for nuclear safeguards, forensics, and consequence management

Kenneth G. W. Inn, C. Martin Johnson, Warren Oldham, Simon Jerome, more

Journal of Radioanalytical and Nuclear Chemistry > 2013 > 296 > 1 > 5-22

A multi-agency workshop was held from 25 to 27 August 2009, at the National Institute of Standards and Technology (NIST), to identify and prioritize the development of radioanalytical Certified Reference Materials (CRMs, generally provided by National Metrology Institutes; Standard Reference Materials, a CRM issued by NIST) for field and laboratory nuclear measurement methods to be used to assess...

article

Gamma spectrometer measurements of microgram quantities of plutonium using uranium L X-rays in the 13–21 keV region

Steven C. Myers, Lav Tandon, Donivan R. Porterfield, Khalil J. Spencer, more

Journal of Radioanalytical and Nuclear Chemistry > 2013 > 296 > 1 > 429-434

Nineteen groups of Marple series cascade impact filters were used to collect aerosol particles associated with various operations in plutonium glove boxes. The cascade impactor separated particles based upon size, while the total mass of plutonium deposited on the filters ranged from 10⁻⁴ to 10⁻⁸ g. Gamma spectrometer measurements with an n-type high-purity germanium detector (HPGe) were performed...

article

The analysis of uranium-232: comparison of radiochemical techniques and an improved method by alpha spectrometry

Magen E. Coleman, Evelyn M. Bond, W. Allen Moody, Lav Tandon

Journal of Radioanalytical and Nuclear Chemistry > 2013 > 296 > 1 > 483-487

Uranium-232 is an isotope of interest for nuclear forensic studies because it can provide information on the irradiation history of a sample of uranium. The isotope is formed in uranium materials through several pathways and is typically found at ultra-trace levels (usually ng/g or smaller) in typical uranium materials. The low abundance of this isotope in irradiated materials makes it very difficult...

article

Plutonium metal standards exchange program for actinide measurement quality assurance (2001–2007)

Lav Tandon, Kevin Kuhn, Diana Decker, Donivan Porterfield, more

Journal of Radioanalytical and Nuclear Chemistry > 2009 > 282 > 2 > 565-571

Plutonium metal exchange programs operated by the Rocky Flats Plant were conducted from 1956–1989 to ensure quality and to compare measurements in a plutonium metal matrix. Los Alamos National Laboratory (LANL) re-established the program in 2001 to assess the quality of analytical chemistry capabilities that support special nuclear material characterization. It is the only program of its kind for...

article

One-dimensional mapping of gamma emitting radionuclides in support of forensic examination

Donivan R. Porterfield, Lav Tandon, Alexander A. Plionis, David J. Mercer, more

Journal of Radioanalytical and Nuclear Chemistry > 2009 > 282 > 3 > 865-868

The development of two generations of a one-dimensional gamma mapping system is described. These systems use high-Z shielding, linear stage, and a high-purity germanium detector. Application to items of forensic interest is described and results for such items are presented. The presented results show the fission product (¹³⁷Cs) and activation product (⁶⁰Co) distributions along one-dimension of an...

article

Establishing reactor operations from uranium targets used for the production of plutonium

Lav Tandon, Kevin Kuhn, Patrick Martinez, Joseph Banar, more

Journal of Radioanalytical and Nuclear Chemistry > 2009 > 282 > 2 > 573-579

This paper presents results from the examination of a number of archived neutron-irradiated uranium targets used for past plutonium production testing. Three of these targets were destructively characterized using Los Alamos National Laboratory actinide analytical chemistry capabilities. A validated conduct-of-operations protocol was followed for this characterization effort. Chemical analyses included...

article

Refinement of Pu parent–daughter isotopic and concentration analysis for forensic (dating) purposes

Khalil J. Spencer, Lav Tandon, Dave Gallimore, Ning Xu, more

Journal of Radioanalytical and Nuclear Chemistry > 2009 > 282 > 2 > 549-554

Plutonium (Pu) metal samples from an interlaboratory exchange exercise and simulated swipe samples were dated using plutonium–uranium (Pu–U) and plutonium–americium (Pu–Am). Metal data were evaluated for consistency and the swipe data against its source material. Metal ages based on ²³⁹Pu versus ²³⁵U and ²⁴⁰Pu versus ²³⁶U agreed to within a few percent, while the ²³⁸Pu–²³⁴U and ²⁴¹Pu–²⁴¹Am measurements...

article

The radiolysis of poly(4-vinylpyridine) quaternary salt ion exchange resins

Kazuyuki Enomoto, Jay A. LaVerne, Lav Tandon, Alejandro E. Enriquez, more

Journal of Nuclear Materials > 2008 > 373 > 1-3 > 103-111

The radiation chemical yields of gaseous products, especially molecular hydrogen (H ₂ ), have been determined in the radiolysis of different poly(4-vinylpyridine) quaternary salt ion exchange resins with up to about 30wt% of absorbed water. Irradiations were performed with 5MeV ⁴ He ions to simulate α-particle radiolysis and with γ-rays for comparison. The resins were quaternary salts...

article

H ₂ and Cl ₂ Production in the Radiolysis of Calcium and Magnesium Chlorides and Hydroxides

Jay A. LaVerne, Lav Tandon

The Journal of Physical Chemistry A > 2005 > 109 > 12 > 2861 - 2865

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Search results for: Lav Tandon

Analytical chemistry of nuclear material: case studies from Los Alamos National Laboratory

The application of radiochronometry during the 4th collaborative materials exercise of the nuclear forensics international technical working group (ITWG)

Uranium assay and trace element analysis of the fourth collaborative material exercise samples by the modified Davies-Gray method and the ICP-MS/OES techniques

Determination of origin and intended use of plutonium metal using nuclear forensic techniques

Chemical investigation of three plutonium–beryllium neutron sources

Nuclear forensic analysis of a non-traditional actinide sample

Forensic investigation of plutonium metal: a case study of CRM 126

Plutonium oxalate precipitation for trace elemental determination in plutonium materials

A lexicon for consistent description of material images for nuclear forensics

Determination of initial fuel state and number of reactor shutdowns in archived low-burnup uranium targets

Dissolution of aerosol particles collected from nuclear facility plutonium production process

The urgent requirement for new radioanalytical certified reference materials for nuclear safeguards, forensics, and consequence management

Gamma spectrometer measurements of microgram quantities of plutonium using uranium L X-rays in the 13–21 keV region

The analysis of uranium-232: comparison of radiochemical techniques and an improved method by alpha spectrometry

Plutonium metal standards exchange program for actinide measurement quality assurance (2001–2007)

One-dimensional mapping of gamma emitting radionuclides in support of forensic examination

Establishing reactor operations from uranium targets used for the production of plutonium

Refinement of Pu parent–daughter isotopic and concentration analysis for forensic (dating) purposes

The radiolysis of poly(4-vinylpyridine) quaternary salt ion exchange resins

H ₂ and Cl ₂ Production in the Radiolysis of Calcium and Magnesium Chlorides and Hydroxides

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