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Current state-of-the-art fission product separations frequently involve multiple independent separation columns and sample manipulation processes; to couple these processes together, multiple evaporation and transposition steps are often required. The addition of these steps results in lengthy separation times, increased analysis costs, the potential for sample loss, and release of radioactive contamination. We report a new semiautomated method for the rapid separation of U, Zr, Mo, Ba, Sr, Te, and lanthanide fission products from irradiated uranium samples. Chemical yields for U, Zr, Ba, Sr, Te and the lanthanides from less than 3-day old uranium fission product samples are consistently greater than 90%, while those of Mo are greater than 70%. This method minimizes the use and addition of oxidation and reduction reagents that often cause issues with retention and separation. Uranium dissolution and fission product separations using this single-pass method are achievable in under 2 h, representing a significant improvement over traditional gravimetric uranium fission product separation procedures.

Analytical methods for separating individual lanthanide elements from each other are needed to support various scientific fields. This work reports a systematic evaluation of analytical separations using Eichrom Industries Ln resin and simple peristaltic pump fed low-pressure chromatography columns. Systematic studies of isocratic elutions over a range of acid concentrations (0.10 to 0.25 M HNO3) and column lengths (15 to 45 cm) show that with careful selection of the separation conditions baseline separation of the majority of the lanthanide elements can be achieved, with the exception Nd, Pr, Pm and Ce which co-elute at low acid concentrations. The employment of a novel Ce3+/Ce4+ oxidation–reduction approach using NaBrO3 and ascorbic acid enables isolation of Ce, however baseline separation of Nd, Pr and Pm could not be accomplished using Ln resin, simple acids, and low-pressure chromatography. A method for rapid separation and preconcentration of fission product lanthanides is also reported based upon the optimized conditions identified in this work; the separation approach enables isolation of lanthanide isotopes in high purity and chemical yield, with final elution fraction volumes of 4 mLs

Quality improvement (QI) is a science of systematic analysis and improvement of health care delivery systems. Working knowledge of QI models is imperative to professional development of future pediatric emergency medicine practitioners. The Accreditation Council for Graduate Medical Education has established a list of QI and patient safety expectations for trainees. In order to address educational needs in this area, we have created a novel QI curriculum for pediatric emergency medicine fellows that include didactic sessions, active participation in QI projects, and mentorship by QI faculty. As a part of the curriculum, fellows are required to participate in variety of QI and patient safety activities, such as Morbidity and Mortality conferences, QI and Patient Case Review committees, and Clinical Care Guideline work groups. As a measure of success, fellows who have participated in this curriculum have shared their successful QI work at the local and national levels. This goal of this report is to share our experience in order to provide other institutions a framework for their own curriculum development.

When post-irradiation materials from the nuclear fuel cycle are released to the environment, certain isotopes of actinides and fission products carry signatures of irradiation history that can potentially aid a nuclear forensic investigation into the material's provenance. In this study, combinations of Pu, Cs, and Ba isotope ratios that produce position (in the reactor core) independent monitors of irradiation history in spent light water reactor fuel are identified and explored. These position independent monitors (PIMs) are modeled for various irradiation scenarios using automated depletion codes as well as ordinary differential equation solutions to approximate nuclear physics models. Experimental validation was performed using irradiated low enriched uranium oxide fuel from a light water reactor, which was sampled at 8 axial positions from a single rod. Plutonium, barium and cesium were chemically separated and isotope ratio measurements of the separated solutions were made by quadrupole and multi-collector inductively coupled mass spectrometry (Cs and Pu, respectively) and thermal ionization mass spectrometry (Ba). The effect of axial variations in neutron fluence and energy spectrum are evident in the measured isotope ratios. Two versions of a combined Pu and Cs based PIM are developed. A linear PIM model, which can be used to solve for irradiation time is found to work well for natural U fuel with

Scandium-47 (

A new nuclear forensic reference material has been characterized as a standard for radiochronometric determination of the model purification date for 137Cs sources. The purification date of a radioactive source is a potentially diagnostic nuclear forensic signature for determining the provenance of a radioactive material. Reference values have been measured for the attributes needed to use the 137Cs/137Ba chronometer: the molality (reported here as nmol g-1) of 137Cs and of the radiogenic portion of 137Ba in the material (hereafter referred to as 137Ba*). All measurement results were decay-corrected to represent the composition of the material on the reference date of July 7, 2011. The molality of 137Cs is (0.7915 ± 0.0073) nmol g-1; this value was calculated from the massic activity of 137Cs, (348.4 ± 3.0) kBq g-1, as measured in the NIST 4π-γ secondary standard ionization chamber (previously calibrated by 4π-(e+x)-γ-coincidence efficiency extrapolation counting) and the evaluated half-life of 137Cs, (30.05 ± 0.08) years. The molality of 137Ba*, (1.546 ± 0.024) nmol g-1, was measured by isotope dilution mass spectrometry using the measured relative proportion of 138Ba in the material to apply a correction for the 137Ba contribution from natural Ba. A model age of (47.04 ± 0.56) years, corresponding to a model purification date of June 22, 1964 with an expanded uncertainty of 200 days is calculated from the reference material values. This age is consistent with the date engraved on the capsule that contained the 137Cs starting material and with a prior independent determination of the model purification date. A full discussion of the uncertainties of the reference material values is included.

Scandium-47 (47Sc) is of high value for targeted radiotherapy and theranostics; we report a novel, cost-effective approach to produce high-purity 47Sc via photonuclear reactions with natural vanadium. Irradiation at 20 MeV photon end-point energy produces >99.998% pure 47Sc, while irradiation at 38 MeV produces 98.8 ± 1.6% pure 47Sc. Experimental data suggest producing greater than 100 mCi (3700 MBq) of 47Sc using this approach may be feasible. Future research into refinement and scale-up to support pre-clinical research is recommended.

Production of certified reference materials in support of domestic nuclear forensics programs require volatile precursors for introduction into electromagnetic isotopic separation instruments. β-Diketone chelates of tetravalent actinides are known for their high volatility, but previously developed synthetic approaches require starting material (NpCl4) that is prohibitively difficult and hazardous to prepare. An alternative strategy was developed here that uses controlled potential electrolysis to reduce neptunium to the tetravalent state in submolar concentrations of hydrochloric acid. Four different β-diketone ligands of varying degrees of fluorination were reacted with an aqueous solution of Np4+. Products of this reaction were characterized via X-ray diffraction and infrared spectroscopy, and were found to be neutral 8-coordinate complexes that adopt square antiprismatic crystal geometry. Synthesis of Np β-diketonates by this approach circumvents the necessity of using NpCl4 in tetravalent Np coordination compound synthesis. The volatility of the complexes was assessed using thermogravimetric analysis, where the temperature of sublimation was determined to be in the range of 180° to 205 °C. The extent of fluorination did not appreciably alter the sublimation temperature of the complex. Thermal decomposition of these compounds was not observed during sublimation. High volatility and thermal stability of Np β-diketonates make them ideal candidates for gaseous introduction into isotopic separation instruments.

Tantalum (Ta), hafnium (Hf), and tungsten (W) analyses from complex matrices require high purification of these analytes from each other and major/trace matrix constituents, however, current state-of-the-art Ta/Hf/W separations rely on traditional anion exchange approaches that show relatively similar distribution coefficient (Kd) values for each element. This work reports an assessment of three commercially available extraction chromatographic resins (TEVA, TRU, and UTEVA) for Ta/Hf/W separations. Batch contact studies show differences in Ta/Hf and Ta/W Kd values of up to 10 6 and 10 4 (respectively), representing an improvement of a factor of 100 and 300 in Ta/Hf and Ta/W Kd values (respectively) over AG1 × 4 resin. Variations in the Kd values as a function of HCl concentration for TRU resin show that this resin is well suited for Ta/Hf/W separations, with Ta/Hf, Ta/W, and W/Hf Kd value improvements of 10, 200, and 30 (respectively) over AG1 × 4 resin. Analyses of digested soil samples (NIST 2710a) using TRU resin and tandem TEVA-TRU columns demonstrate the ability to achieve extremely high purification (>99%) of Ta and W from each other and Hf, as well as enabling very high purification of Ta and W from the major and trace elemental constituents present in soils using a single chromatographic step.

This chapter provides an overview and description of the challenges health care workers face when encountering pediatric patients in emergency settings. Children make up a substantial portion of annual visits to US emergency departments, though most children are seen in settings where adults make up the majority of the patient volume, meaning there is often a lack of comfort in communicating with children. Special attention is paid in this chapter to the importance of the “triadic” nature of the visit (provider-child-parent), introductions and body language, pediatric developmental stages, issues of consent and confidentiality, and decision-making capacity. The chapter uses case examples of commonly encountered clinical scenarios to provide tips and tricks for engaging with pediatric patients in these stressful situations. Case examples include the reticent child, the painful procedure, delivering bad news, the angry parent, and the overtalkative parent.

A new nuclear forensic reference material has been characterized as a standard for radiochronometric determination of the model purification date for

With a half-life of 3.85(5) d, the fission product $^{127}\mathrm{Sb}$ is potentially useful for the characterization of fallout debris that would be collected for forensic analysis following a hypothetical nuclear event. The $\ensuremath{\beta}$ decay of $^{127}\mathrm{Sb}$ has many characteristic $\ensuremath{\gamma}$-ray lines, however, the majority of decay strength is concentrated in the three strongest lines near 686, 473, and 784 keV, based on low-precision spectroscopic measurements from decades ago. In a new measurement of $^{127}\mathrm{Sb}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$ decay, obtained from radiochemical separations of U photofission products, we show that the energies of the 686 and 784 lines are actually shifted lower by 0.8 and 1.1 keV, respectively. Such large discrepancies in the nuclear data inhibit accurate isotopic analyses and have important implications, for example, on the assessment of fission debris that might be collected in the days following a nuclear event. Therefore, a new evaluation of $^{127}\mathrm{Sb}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$ decay and appropriate revisions to the various nuclear databases are warranted. This paper reports a new set of $\ensuremath{\gamma}$-ray energies and relative intensities corresponding to $^{127}\mathrm{Sb}$ decay.

Introduction: Children’s Hospital Colorado is an academic, tertiary-care Level 1 Trauma Center with an emergency department (ED) that treats >70,000 patients/year. Patient volumes continue to increase, leading to worsening wait times and left-without-being-seen (LWBS) rates. In 2015, the ED’s median door-to-provider time was 49 minutes [interquartile range (IQR) = 26–90], with a 3.2% LWBS rate. ED leadership, staff, and providers aimed to improve patient flow with specific goals to (1) decrease door-to-provider times to a median of

The method of input accountancy for a used oxide fuel reprocessing plant has been based on the sampling of a homogenized liquid stream of dissolved used oxide fuel. This article presents an alternative sampling strategy where samples are taken directly from solid oxides. The strategy is to obtain a representative sample while not requiring the homogenization of the input materials. A theoretical derivation is given to determine the sample quantity for satisfying the sampling error requirement.

X-ray fluorescence (XRF) is an attractive technique for nuclear forensics applications. We evaluated a handheld XRF device by applying an external radiation field (10 mR/h–17 R/h) using two types of radiography sources: a 60Co radiography camera for high-energy gamma emissions and an 192Ir radiography camera for several low-energy gamma (0.604, 0.468, and 0.317 MeV) and decay daughter X-ray emissions. External radiation tests proved that radiation, in general, has a significant effect on the dead time or background at dose rates over 1 R/h for both the 192Ir and 60Co sources.

Isotope dilution mass spectrometry (IDMS) is an analytical technique capable of providing accurate and precise quantitation of trace isotope abundance and assay providing measurement uncertainties below 1 %. To achieve these low uncertainties, the IDMS method ideally utilizes chemically pure “spike” solutions that consist of a single highly enriched isotope that is well-characterized relating to the abundance of companion isotopes and concentration in solution. To address a current demand for accurate 137Cs/137Ba ratio measurements for “age” determination of radioactive 137Cs sources, Idaho National Laboratory (INL) is producing enriched 134Ba isotopes that are tobe used for IDMS spikes to accurately determine 137Ba accumulation from the decay of 137Cs. The final objective of this work it to provide a homogenous set of reference materials that the National Institute of Standards and Technology can certify as standard reference materials used for IDMS. The process that was developed at INL for the separation and isolation of Ba isotopes, chemical purification of the isotopes in solution, and the encapsulation of the materials will be described.

The production of glass that emulates fallout is desired by the nuclear forensics community for training and measurement exercises. The composition of nuclear fallout is complex, with widely varying isotopic compositions (Fahey et al., Proc Natl Acad Sci USA 107(47):20207–20212, 2010; Bellucci et al., Anal Chem 85:7588–7593, 2013; Wallace et al., J Radioanal Nucl Chem, 2013; Belloni et al., J Environ Radioact 102:852–862, 2011; Freiling, Science 139:1058–1059, 1963; Science 133:1991–1999, 1961; Bunney and Sam Government Report: Naval Ordinance Laboratory, White Oak, 1971). As the gaseous cloud traverses from hotter to cooler regions of the atmosphere, the processes of condensation and nucleation entrain environmental materials, vaporized nuclear materials and fission products. The elemental and isotopic composition of the fission products is altered due to chemical fractionation (i.e. the fission product composition that would be expected from fission of the original nuclear material is altered by differences in condensation rates of the elements); the fallout may be enriched or depleted in volatile or refractory fission products. This paper describes preliminary work to synthesize, irradiate and fractionate the fission product content of irradiated particulate glass using a thermal distillation 2 h after irradiation. The glass was synthesized using a solution-based polymerization of tetraethyl orthosilicate. (Izrael, Radioactive fallout after nuclear explosions and accidents, 2002) Uranium was incorporated into the glass particulate at trace concentrations during polymerization. The particulate was subjected to a short thermal neutron irradiation then heated to 1,273 K approximately 2 h after the end of irradiation. Fission products of 133, 134, 135I, 132, 134Te, 135Xe, 138Cs and 91, 92Sr were observed to be distilled from the particulate. The results of these preliminary studies are discussed.

Research is underway to develop instruments and methods to determine the activity of radionuclides present in the fallout debris from the detonation of a radiological dispersal device (RDD). Handheld instruments, including commonly used health physics survey instruments, have been incorporated into a portable telemetry kit containing a global positioning system receiver, WiFi and radio communications, and a small microcomputer to facilitate data processing, logging, and transmission. An operator carries the system and walks through the RDD post-blast environment, real-time radiological data is logged, stored locally, and transmitted to a base station outside of the RDD hot zone. A map of the distributed radiological dispersal is generated, subdividing the world into 1-m2 squares. Separate measurements of ground activity taken at a finite number of discrete locations is used to cross-correlate the survey data, transforming the health physics data (e.g., mrem hr−1) to surface activity (Bq m−2). The map data, smoothed using standard Kriging approaches, is then analyzed by summing each discrete square area, producing an estimate for the total dispersed ground activity. The instrumentation and method have been field tested multiple times at Idaho National Laboratory during field exercises using short-lived radionuclides detonated in small-scale experiments.

Idaho National Laboratory (INL) operates a mass separator that is currently producing high purity isotopes for use as internal standards for high precision isotope dilution mass spectrometry (IDMS). In 2008, INL began the revival of the vintage 1970s era instrument. Advancements thus far include the successful upgrading and development of system components such as the vacuum system, power supplies, ion-producing components, and beam detection equipment. Progress has been made in the separation and collection of isotopic species including those of Ar, Kr, Xe, Sr, and Ba. Particular focuses on ion source improvements and developments have proven successful with demonstrated output beam currents of over 10 μA 138Ba and 350 nA 134Ba from a natural abundance Ba source charge (~2.4 % 134Ba). In order to increase production and collection of relatively high quantities (mg levels) of pure isotopes, several improvements have been made in ion source designs, source material introduction, and ion detection and collection. These improvements have produced isotopes of high purity (>98 %) and in quantities in the tens of micrograms per run. The instrument and results for pure isotope production for IDMS standards will be presented.

Source term information is required for to reconstruct a device used in a dispersed radiological dispersal device. Simulating a radioactive environment to train and exercise sampling and sample characterization methods with suitable sample materials is a continued challenge. The Idaho National Laboratory has developed and permitted a radioactive response training range (RRTR), an 800 acre test range that is approved for open air dispersal of activated KBr, for training first responders in the entry and exit from radioactively contaminated areas, and testing protocols for environmental sampling and field characterization. Members from the Department of Defense, Law Enforcement, and the Department of Energy participated in the first contamination exercise that was conducted at the RRTR in the July 2011. The range was contaminated using a short lived radioactive 82Br isotope (activated KBr). Soil samples contaminated with KBr (dispersed as a solution) and glass particles containing activated potassium bromide that emulated dispersed radioactive materials (such as ceramic-based sealed source materials) were collected to assess environmental sampling and characterization techniques. This presentation summarizes the performance of a radioactive materials surrogate for use as a training aide for nuclear forensics.

A radioactive 137Cs source has been analyzed for the radioactive parent 137Cs and stable decay daughter 137Ba. The ratio of the daughter to parent atoms is used to estimate the date when Cs was purified prior to source encapsulation (an “age” since purification). The isotopes were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) after chemical separation. In addition, Ba was analyzed by isotope dilution ICP-MS (ID-ICP-MS). A detailed error analysis of the mass spectrometric work has been undertaken to identify areas of improvement, as well as quantifying the effect the errors have on the “age” determined. This paper reports an uncertainty analysis to identifying areas of improvement and alternative techniques that may reduce the uncertainties. In particular, work on isotope dilution using ICP-MS for the “age” determination of sealed sources is presented. The results will be compared to the original work done using external standards to calibrate the ICP-MS instrument.

Two Americium–Beryllium neutron sources were dismantled, sampled (sub-sampled) and analyzed via inductively coupled plasma mass spectrometry (ICP-MS). Characteristics such as “age” since purification, actinide content, trace metal content and inter and intra source composition were determined. The “age” since purification of the two sources was determined to be 25.0 and 25.4 years, respectively. The systematic uncertainties in the “age” determination were ±4% 2σ. The amount and isotopic composition of U and Pu varied substantially between the sub-samples of Source 2 (n = 8). This may be due to the physical means of sub-sampling or the way the source was manufactured. Source 1 was much more consistent in terms of content and isotopic composition (n = 3 sub-samples). The Be–Am ratio varied greatly between the two sources. Source 1 had an Am–Be ratio of 6.3 ± 52% (1σ). Source 2 had an Am–Be ratio of 9.81 ± 3.5% (1σ). In addition, the trace element content between the samples varied greatly. Significant differences were determined between Sources 1 and 2 for Sc, Sr, Y, Zr, Mo, Ba and W.

A gas pressurized extraction chromatography (GPEC) system has been developed to perform elemental separations on radioactive samples to determine total and isotopic compositions of Cs and Ba from an irradiated salt sample, fuel sample and two sealed radiation sources. The GPEC system employs compressed nitrogen to move liquid through the system, compared to gravity or pumped liquids that are typically used for separations. A commercially available Sr-Resin™ was used to perform the separation for the above mentioned analytes. A 1% acetic acid solution was determined to be the best extractant for Ba. A flow rate of 0.1 mL/min was determined to be optimal for the separation of Ba. Complete recovery of the Cs and Ba was achieved, within the systematic uncertainties of the experiments.

Objectives The goal of this study was to determine the impact of race on identification of hypertrophic cardiomyopathy (HCM). Background Sudden death in young competitive athletes is due to a variety of cardiovascular diseases (CVDs) and, most commonly, HCM. These catastrophes have become an important issue for African Americans, although HCM has been previously regarded as rare in this segment of the U.S. population. Methods We studied the relationship of race to the prevalence of CVDs causing sudden death in our national athlete registry, and compared these findings with a representative multicenter hospital-based cohort of patients with HCM. Results Of 584 athlete deaths, 286 were documented to be due to CVD at ages 17 +/- 3 years; 156 (55%) were white, and 120 (42%) were African American. Most were male (90%), and 67% participated in basketball and football. Among the 286 cardiovascular deaths, most were due to HCM (n = 102; 36%) or anomalous coronary artery of wrong sinus origin (n = 37; 13%). Of the athletes who died of HCM, 42 (41%) were white, but 56 (55%) were African American. In contrast, of 1,986 clinically identified HCM patients, only 158 (8%) were African American (p Conclusions In this autopsy series, HCM represented a common cause of sudden death in young and previously undiagnosed African American male athletes, in sharp contrast with the infrequent clinical identification of HCM in a hospital-based population (i.e., by seven-fold). This discrepancy suggests that many HCM cases go unrecognized in the African American community, underscoring the need for enhanced clinical recognition of HCM to create the opportunity for preventive measures to be employed in high-risk patients with this complex disease.

A study was performed to evaluate the performance characteristics of a laser-induced plasma for real-time determination of various gas-phase metal hydrides, specifically Sn and As. The choice of carrier gas composition and the effect of the pressure on the temporal emission behavior of neutral atoms excited by the laser-induced plasma were investigated. Metal hydrides were generated by using a NaBH4-based hydride generation system. The hydrides were equilibrated into an evacuated cell and isolated from the generator prior to measurement. Laser-induced breakdown spectroscopy (LIBS) spectra of Sn and As were recorded in He and N2 atmospheres at 300 and 760 Torr. The temporal behavior of the LIBS signal was most affected by gas composition, gas pressure, and intensity of the laser beam. The Sn neutral atom emission (284.0 nm) in a N2 atmosphere decreased exponentially with time. In contrast, with a He atmosphere and identical experimental conditions, the Sn signal increased logarithmically with time over the first 100 s. Then the signal maintained a steady-state value until approximately 400 s, after which it decreased exponentially. The steady-state time depends on the concentration of metal hydride. The variation of the LIBS signal with time was mirrored for the As neutral atom emission in He and N2 atmospheres. Various experiments have been performed to find the possible reason for the signal variation with time. It was found that chemical reactions in the laser plasma that might deplete the metal from the gas volume were responsible for the decrease in the signal with time.

A supplementary electrical discharge is generated by extracting the axial channel of an Ar inductively coupled plasma (ICP) through a circular (0.5 mm diameter) sampling orifice into a small vacuum chamber. Emission is observed from just outside the sampling orifice and from the adjacent region of the plasma upstream of the sampler. The discharge enhances the intensities of several Ca II and Sc II lines but does not broaden the lines or otherwise perturb the line shapes. The sampling orifice does not introduce any additional memory or extend the rinse-out time required to change samples. Sodium concomitant at concentrations up to 1000 mg 1 −1 suppresses the intensities of analyte lines by 5–30%, depending upon the particular line involved. Sodium at 5000 mg 1 −1 suppresses either ion lines or neutral atom lines by 40–60%. This suppression effect is more severe than that generally observed under normal operating conditions when observing emission from the ICP alone. The additional suppression is attributed to a change in the spatial distribution of emission induced by the discharge and the gas flow into the sampler.

A detailed parametric study of axially-observed emission from imploding thin film plasmas was performed in order to determine the optimum electrical and physical discharge conditions for analytical spectrometric measurements. Discharge energy, frequency and resistance were systematically varied and analyte emission from the plasma observed both with and without spatial and temporal resolution. The effects of discharge tube diameter and length were also investigated. Low-inductance underdamped discharges produced the most complex emission features, with self-reversal of analyte ion lines predominating during the current maxima and most positive analyte emission originating from axially-expelled plasma vapor. Temporal separation of absorption and emission components of the signal were best facilitated by the use of a critically damped (unipolar) discharge, which retained the high-power densities desired for efficient atomization yet allowed detection of vanadium at the low-ng level. Axial observation limits the analytical dynamic range due to self-absorption from the axially-expelled vapor. Radial observation of emission or re-excitation of the sampled vapor by ICP or MIP is suggested for more efficient measurement of analyte produced by this atom cell.

A detailed study of the electrical properties of imploding thin film plasmas was performed. A method for the determination of circuit resistance and inductance values from an underdamped discharge current waveform is summarized and discussed in detail. The effects of plasma tube length, charging voltage, circuit inductance and resistance were investigated with respect to both plasma and discharge circuit power dissipation properties. Peak power-densities > 1 MW cm 3 were observed for all discharge conditions, but significant differences in circuit energy transfer efficiencies and the temporal distribution of plasma power dissipation were apparent. The most efficient energy transfer properties were observed with discharges performed with no added inductance or resistance; these discharges also delivered the greatest amount of energy to the plasma in the shortest period of time. Critically-damping the discharge by the addition of a 900 mΩ external resistance decreased the energy transfer efficiency significantly, but also produced a unipolar current waveform demonstrating characteristics which may allow both efficient sample atomization and excitation.

Application of an isotope-dilution method for determining 90Zr and 90Sr in a 90Sr source material spiked with 86Sr and 92Zr is described. A miniature gas pressurized extraction chromatography (GPEC) system with a column containing Eichrom Sr Resin™ was used for separating the elements so isobaric isotopes could be measured by mass spectrometry. Zirconium was rinsed through the column with 3 M HNO3/trace HF and strontium was eluted with 1% acetic acid. Two mass spectrometric techniques, inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry (TIMS), were used for measuring isotope ratios. Data were obtained with 90Sr from a blood-irradiator source. Results from the TIMS measurements gave a decay time of 45.16 ± 0.26 years, and those from the ICP-MS gave 45.24 ± 0.20 years (uncertainties are expanded uncertainty, k = 2). Quadrupole ICP-MS is preferable to TIMS in this application if the ICP-MS data are suitably corrected for non-linearity and mass discrimination.

Source a plasma a couche mince pour l'analyse spectrochimique atomique d'echantillons solides

In many applications, photomultiplier tubes (PMTs) must be operated at high gains in order for one to obtain adequate detection of low-light-level signals. However, when an intense light pulse immediately precedes the low-level light signal, the PMT may be promoted into a state of saturation. Saturation is the nonlinear enhancement of the anode current with respect to the intense photon flux incident upon the photocathode. This is caused by the redistribution of the biasing potential across the dynode chain. The last dynodes are unable to be sustained at a constant potential because of space charge depletion of the dynode surfaces. Further illumination of the photocathode results in a nonlinear increase in photocurrent. Saturation effects may last up to several microseconds, rendering the photomultiplier tube inoperable. In the extreme, intense light pulses may result in permanent damage to the MPT.

The sampling method used for inductively coupled plasma mass spectrometry (ICP-MS) is studied using atomic emission and atomic fluorescence spectrometry to provide information about conditions during the extraction process. Gas kinetic temperatures in the Mach disc region of the extracted plasma are of the order of 2200 K and indicate that collisions in the Mach disc re-heat the sampled gas substantially. Fluorescence studies indicate that there is little neutral sodium inside the zone of silence of the free jet, which shows that little ion-electron recombination occurs during the initial extraction and supersonic expansion, also, there are few excited barium ions inside the zone of silence. These observations substantiate previous theoretical descriptions of the various properties of supersonic jets extracted from inductively coupled plasmas.