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Results for “CESIUM 133”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

The optical pumping of alkali atoms using coherent radiation from semi-conductor injection lasers and incoherent radiation from resonance lamps

An experimental study for creating population differences in the ground states of alkali atoms (Cesium 133) is presented. Studies made on GaAs-junction lasers and the achievement of population inversions among the hyperfine levels in the ground state of Cs 133 by optically pumping it with radiation from a GaAs diode laser. Laser output was used to monitor the populations in the ground state hyperfine levels as well as to perform the hyperfine pumping. A GaAs laser operated at about 77 K was used to scan the 8521 A line of Cs 133. Experiments were performed both with neon-filled and with paraflint-coated cells containing the cesium vapor. Investigations were also made for the development of the triple resonance coherent pulse technique and for the detection of microwave induced hyperfine trasistions by destroying the phase relationships produced by a radio frequency pulse. A pulsed cesium resonance lamp developed, and the lamp showed clean and reproducible switching characteristics.

Singh, G.↗
DOE OSTI2016

Measurement of the mass attenuation coefficient from 81 keV to 1333 keV for elemental materials Al, Cu and Pb

The mass attenuation coefficients (μ/ρ) for 3 high purity elemental materials Al, Cu and Pb were measured in the γ-ray energy range from 81 keV up to 1333 keV using {sup 22}Na, {sup 60}Co {sup 133}Ba and {sup 133}Cs as sources of gamma radiation. Well shielded detector (NaI (Tl) semiconductor detector) was used to measure the intensity of the transmitted beam. The measurements were made under condition of good geometry, assuring that any photon absorbed or deflected appreciably does not reach the detector. The measured values are compared with the theoretical ones obtained by Seltzer (1993).

07 ISOTOPE AND RADIATION SOURCES↗
NASA NTRS1988

The Stable Solar Analyzer

Progress in the development of an instrument with very high (1:10 billion) wavelength stability designed to measure solar surface velocities and magnetic fields is reported. The instrument determines Doppler and Zeeman shifts in solar spectral lines by a 6-point weighted average. It is built around an electrically tunable solid lithium-niobate Fabry-Perot etalon that is stabilized against a diode laser which itself is locked to a resonance line of cesium 133. Key features are the etalon, which acts as a wide-angle 0.017-nm solar filter, the camera with a specially stabilized shutter, and the instrument control and data collection system. Use of the instrument in helioseismological research is emphasized.

Rust, D. M.↗
DOE OSTI2017

A low abundance of “{sup 35}cs in the early solar system from barium isotopic signatures of volatile-depleted meteorites

Precise knowledge of the abundances of short-lived radionuclides at the start of the solar system leads to fundamental information about the stellar environment of solar system formation. Previous investigations of the short-lived {sup 135}Cs →{sup 135}Ba system (t {sub 1/2} = 2.3 Ma) have resulted in a range of calculated initial amounts of {sup 135}Cs, with most estimates elevated to a level that requires extraneous input of material to the protoplanetary disk. Such an array of proposed {sup 135}Cs/{sup 133}Cs initial solar system values has severely restricted the system’s use as both a possible chronometer and as an informant about supernovae input. However, if {sup 135}Cs was as abundant in the early solar system as previously proposed, the resulting deficits in its daughter product {sup 135}Ba would be easily detectable in volatile-depleted parent bodies (i.e., having sub-chondritic Cs/Ba) from the very early solar system. In this work, we show that angrites and eucrites, which were volatile-depleted within ∼1 million years of the start of the solar system, do not possess deficits in {sup 135}Ba compared to other planetary bodies. From this, we calculate an upper limit for the initial {sup 135}Cs/{sup 133}Cs of 2.8 × 10{sup −6}, well below previous estimates. This significantly lower initial {sup 135}Cs/{sup 133}Cs ratio now suggests that all of the {sup 135}Cs present in the early solar system was inherited simply from galactic chemical evolution and no longer requires an addition from an external stellar source such as an asymptotic giant branch star or SN II, corroborating evidence from several other short-lived radionuclides.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

Reactor Fuel Isotopics and Code Validation for Nuclear Applications

Experimentally measured isotopic concentrations of well characterized spent nuclear fuel (SNF) samples have been collected and analyzed by previous researchers. These sets of experimental data have been used extensively to validate the accuracy of depletion code predictions for given sets of burnups, initial enrichments, and varying power histories for different reactor types. The purpose of this report is to present the diversity of data in a concise manner and summarize the current accuracy of depletion modeling. All calculations performed for this report were done using the Oak Ridge Isotope GENeration (ORIGEN) code, an internationally used irradiation and decay code solver within the SCALE comprehensive modeling and simulation code. The diversity of data given in this report includes key actinides, stable fission products, and radioactive fission products. In general, when using the current ENDF/B-VII.0 nuclear data libraries in SCALE, the major actinides are predicted to within 5% of the measured values. Large improvements were seen for several of the curium isotopes when using improved cross section data found in evaluated nuclear data file ENDF/B-VII.0 as compared to ENDF/B-V-based results. The impact of the flux spectrum on the plutonium isotope concentrations as a function of burnup was also shown. The general accuracy noted for the actinide samples for reactor types with burnups greater than 5,000 MWd/MTU was not observed for the low-burnup Hanford B samples. More work is needed in understanding these large discrepancies. The stable neodymium and samarium isotopes were predicted to within a few percent of the measured values. Large improvements were seen in prediction for a few of the samarium isotopes when using the ENDF/B-VII.0 libraries compared to results obtained with ENDF/B-V libraries. Very accurate predictions were obtained for 133 Cs and 153 Eu. However, the predicted values for the stable ruthenium and rhodium isotopes varied as much as 10% of the measured values, and 109 Ag was consistently over-predicted by as much as 170%. In general, there is a larger uncertainty for modeling radioactive fission products when compared to either the actinides or the stable fission products in SNF. The relative C/E ratios ranged from a few percent for 137 Cs up to 60% and 100% for 106 Ru and 125 Sb, respectively. Limited or no radioactive fission products data exist in the current data sets for reactor types other than PWRs and BWRs. More work is needed in obtaining a greater diversity of radioactive fission product data. While performing this survey, issues leading to inconsistencies in nuclear fission yield data were discovered that specifically impacted the fission product noble gases. Emphasis was given to this legacy data, and corrective actions were taken as described in this report. After the fission yield data were corrected, the stable xenon and krypton fission products were predicted to within 5% of their measurements. However, preliminary results not explicitly given in this report indicate that the relative C/E ratio for the radioactive isotope 85 Kr varied as much as 10%. Due to the complex migration and the difficulty in measuring noble gases in the fuel, a more thorough investigation is needed to understand how accurately depletion codes can calculate these gas concentrations.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2018

The Effect of an Antirelaxation Coating on Absorption in the D{sub 2} Lines of Alkali Metals

The specific features of absorption in a cell with an antirelaxation coating related to optical pumping and a finite rate of laser-frequency scanning are studied. The internal state of an atom in such cells is likely to remain unaltered after a collision with a wall. This results in optical pumping of an atomic ensemble over all velocities and the entire cell volume. Both the frequency corresponding to the maximum absorption in the D{sub 2} line of {sup 133}Cs and the absorption maximum itself depend on the sign of laser-frequency scanning. A theoretical model attributing the power dependence of asymmetry of the absorption contour of the {sup 133}Cs D{sub 2} line to the presence of cyclic transition levels in the system is presented.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2015

The determination of potential energy curve and dipole moment of the (5)0{sup +} electronic state of {sup 85}Rb{sup 133}Cs molecule by high resolution photoassociation spectroscopy

We present the formation of ultracold {sup 85}Rb{sup 133}Cs molecules in the (5)0{sup +} electronic state by photoassociation and their detection via resonance-enhanced two-photon ionization. Up to v = 47 vibrational levels including the lowest v = 0 vibrational and lowest J = 0 levels are identified with rotationally resolved high resolution photoassociation spectra. Precise Dunham coefficients are determined for the (5)0{sup +} state with high accuracy, then the Rydberg-Klein-Rees potential energy curve is derived. The electric dipole moments with respect to the vibrational numbers of the (5)0{sup +} electronic state of {sup 85}Rb{sup 133}Cs molecule are also measured in the range between 1.9 and 4.8 D. These comprehensive studies on previously unobserved rovibrational levels of the (5)0{sup +} state are helpful to understand the molecular structure and discover suitable transition pathways for transferring ultracold atoms to deeply bound rovibrational levels of the electronic ground state.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Data on photoneutron reactions from various experiments for {sup 133}Cs, {sup 138}Ba and {sup 209}Bi nuclei

Basic methods for determining cross sections for photoneutron partial reactions are examined. They are obtained directly in experiments with quasimonoeneregetic annihilation photons or from the cross section for the (γ, xn) = (γ, 1n) + 2(γ, 2n) + 3(γ, 3n) +... neutron-yield reaction in experiments with bremsstrahlung photons by introducing corrections based on statistical nuclear-reaction theory. The difference in the conditions of these experiments, which leads to discrepancies between their results because of sizable systematic errors, is analyzed. Physical criteria are used to study the reliability of data on the photodisintegration of {sup 133}Cs, {sup 138}Ba, and {sup 209}Bi nuclei. The cross sections for partial and total reactions satisfying the reliability criteria are evaluated within the experimental–theoretical method (σ{sup eval}(γ, in) = F{sub i}{sup theor} × σ{sup expt}(γ, xn)) on the basis of the experimental cross sections σ{sup expt}(γ, xn) and the results of the calculations within the combined model of photonuclear reactions.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2016

Comparison of sub-Doppler-width resonances in transmission and reflection spectra of micrometer-thick Cs vapor layers

We report experimental study of resonance sign reversal at the hyperfine F{sub g} = 4 → F{sub e} = 5 transition on D{sub 2} line of {sup 133}Cs. Alkali vapors are confined in an optical cell with micrometric thickness. For circular polarization of the irradiating light, transmission and reflection spectra, recorded at different laser intensities and different temperature of alkali vapor, are studied and compared. At low laser intensity, in the transmission spectra we observe a narrow resonance of increased absorption (bright resonance) at the F{sub g} = 4 → F{sub e} = 5 transition, however in reflection spectra, recorded at the same experimental conditions, this bright resonance transforms into a dark resonance of reduced absorption. A simple explanation is proposed in order to explain the observed difference between the transmission and reflection spectra.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Alkali-vapor magnetic resonance driven by fictitious radiofrequency fields

We demonstrate an all-optical {sup 133}Cs scalar magnetometer, operating in nonzero magnetic field, in which the magnetic resonance is driven by an effective oscillating magnetic field provided by the AC Stark shift of an intensity-modulated laser beam. We achieve a projected shot-noise-limited sensitivity of 1.7fT/√(Hz) and measure a technical noise floor of 40fT/√(Hz). These results are essentially identical to a coil-driven scalar magnetometer using the same setup. This all-optical scheme offers advantages over traditional coil-driven magnetometers for use in arrays and in magnetically sensitive fundamental physics experiments, e.g., searches for a permanent electric dipole moment of the neutron.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Long-range interactions between polar bialkali ground-state molecules in arbitrary vibrational levels

We have calculated the isotropic C{sub 6} coefficients characterizing the long-range van der Waals interaction between two identical heteronuclear alkali-metal diatomic molecules in the same arbitrary vibrational level of their ground electronic state X{sup 1}Σ{sup +}. We consider the ten species made up of {sup 7}Li, {sup 23}Na, {sup 39}K, {sup 87}Rb, and {sup 133}Cs. Following our previous work [Lepers et al., Phys. Rev. A 88, 032709 (2013)], we use the sum-over-state formula inherent to the second-order perturbation theory, composed of the contributions from the transitions within the ground state levels, from the transition between ground-state and excited state levels, and from a crossed term. These calculations involve a combination of experimental and quantum-chemical data for potential energy curves and transition dipole moments. We also investigate the case where the two molecules are in different vibrational levels and we show that the Moelwyn-Hughes approximation is valid provided that it is applied for each of the three contributions to the sum-over-state formula. Our results are particularly relevant in the context of inelastic and reactive collisions between ultracold bialkali molecules in deeply bound or in Feshbach levels.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2017

Modern status of photonuclear data

The reliability of experimental cross sections obtained for (γ, 1n), (γ, 2n), and (γ, 3n) partial photoneutron reactions using beams of quasimonoenergetic annihilation photons and bremsstrahlung is analyzed by employing data for a large number of medium-heavy and heavy nuclei, including those of {sup 63,65}Cu, {sup 80}Se, {sup 90,91,94}Zr, {sup 115}In, {sup 112−124}Sn, {sup 133}Cs, {sup 138}Ba, {sup 159}Tb, {sup 181}Ta, {sup 186−192}Os, {sup 197}Au, {sup 208}Pb, and {sup 209}Bi. The ratios of the cross sections of definite partial reactions to the cross section of the neutron-yield reaction, F{sub i} = σ(γ, in)/σ(γ, xn), are used as criteria of experimental-data reliability. By definition, positive values of these ratios should not exceed the upper limits of 1.00, 0.50, 0.33,... for i = 1, 2, 3,..., respectively. For many nuclei, unreliable values of the above ratios were found to correlate clearly in various photon-energy regions F{sub i} with physically forbidden negative values of cross sections of partial reactions. On this basis, one can conclude that correspondent experimental data are unreliable. Significant systematic uncertainties of the methods used to determine photoneutron multiplicity are shown to be the main reason for this. New partial-reaction cross sections that satisfy the above data-reliability criteria were evaluated within an experimental–theoretical method [σ{sup eval}(γ, in) = F{sub i}{sup theor} (γ, in) × σ{sup expt}(γ, xn)] by employing the ratios F{sub i}{sup theor} (γ, in) calculated on the basis of a combined photonuclear-reaction model. It was obtained that cross sections evaluated in this way deviate substantially from the results of many experiments performed via neutron-multiplicity sorting, but, at the same time, agree with the results of alternative activation experiments. Prospects of employing methods that would provide, without recourse to photoneutron-multiplicity sorting, reliable data on cross sections of partial photoneutron reactions are discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Versatile cold atom source for multi-species experiments

We present a dual-species oven and Zeeman slower setup capable of producing slow, high-flux atomic beams for loading magneto-optical traps. Our compact and versatile system is based on electronic switching between different magnetic field profiles and is applicable to a wide range of multi-species experiments. We give details of the vacuum setup, coils, and simple electronic circuitry. In addition, we demonstrate the performance of our system by optimized, sequential loading of magneto-optical traps of lithium-6 and cesium-133.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Instrument for precision long-term β-decay rate measurements

We describe an experimental setup for making precision measurements of relative β-decay rates of {sup 22}Na, {sup 36}Cl, {sup 54}Mn, {sup 60}Co, {sup 90}Sr, {sup 133}Ba, {sup 137}Cs, {sup 152}Eu, and {sup 154}Eu. The radioactive samples are mounted in two automated sample changers that sequentially position the samples with high spatial precision in front of sets of detectors. The set of detectors for one sample changer consists of four Geiger-Müller (GM) tubes and the other set of detectors consists of two NaI scintillators. The statistical uncertainty in the count rate is few times 0.01% per day for the GM detectors and about 0.01% per hour on the NaI detectors. The sample changers, detectors, and associated electronics are housed in a sealed chamber held at constant absolute pressure, humidity, and temperature to isolate the experiment from environmental variations. The apparatus is designed to accumulate statistics over many years in a regulated environment to test recent claims of small annual variations in the decay rates. We demonstrate that absent this environmental regulation, uncontrolled natural atmospheric pressure variations at our location would imprint an annual signal of 0.1% on the Geiger-Müller count rate. However, neither natural pressure variations nor plausible indoor room temperature variations cause a discernible influence on our NaI scintillator detector count rate.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Radioisotope identification method for poorly resolved gamma-ray spectrum of nuclear security concern

Gamma-ray signal can be used as a fingerprint for radioisotope identification. In the context of radioactive and nuclear materials security at the border control point, the detection task can present a significant challenge due to various constraints such as the limited measurement time, the shielding conditions, and the noise interference. This study proposes a novel method to identify the signal of one or several radioisotopes from a poorly resolved gamma-ray spectrum. In this method, the noise component in the raw spectrum is reduced by the wavelet decomposition approach, and the removal of the continuum background is performed using the baseline determination algorithm. Finally, the identification of radioisotope is completed using the matrix linear regression method. The proposed method has been verified by experiments using the poorly resolved gamma-ray signals from various scenarios including single source, mixing of natural uranium with five of the most common industrial radioactive sources (57Co, 60Co, 133Ba, 137Cs, and 241Am). The preliminary results show that the proposed algorithm is comparable with the commercial method.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Measurements of radiological data of some amino acids in the energy range 0.122-1.330MeV

Radiological parameters such as μ{sub m}, σ{sub t}, σ{sub e}, Z{sub eff} and N{sub eff} of amino acids, namely Lysine (C{sub 6}H{sub 15}N{sub 2}O{sub 2}), Histidine (C{sub 6}H{sub 9}N{sub 3}O{sub 2}) and Arginine (C{sub 6}H{sub 15}N{sub 4}O{sub 2}), were measured using NaI (Tl)-based gamma spectrometry. Radioactive sources used in the study are {sup 57}Co, {sup 133}Ba, {sup 137}Cs, {sup 54}Mn, {sup 60}Co and {sup 22}Na. Gamma ray transmission method in a narrow beam good geometry set up was used in the study. The measured data were compared against XCOM-based data. The agreement is within 2%.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2017

Further Development of an ISOCS - based Advanced In Situ Gamma Spectrometry Services Tool for Waste Measurements - 17452

Canberra's In Situ Object Counting System is an established tool used for gamma spectrometry allowing a physical representation of complex geometries and mathematical calculation of the calibration function while avoiding the need for radioisotope standards. The ISOCS Uncertainty Estimator tool can be used to calculate defensible systematic calibration uncertainties. However the uncertainties depend on knowledge of the properties of the item being measured and for poorly characterized materials these can be large, often leading to large costs for waste sentencing. An ISOCS-based advanced in-situ gamma spectrometry services tool has been developed to reduce those uncertainties. This system is based on generating and comparing a range of candidate geometry models that yield figures of merit indicative of improved consistency between modelled data and available diverse measurement data. The approach and results of initial performance testing have previously been published, demonstrating an analysis procedure and enhanced accuracy for measurement of a low density 200 litre waste drum, based on measurements with known sources placed at different positions. It was shown how the accuracy of assay of Am-241 in a light matrix can be significantly improved. Further analysis has now been performed, with reference to measurements of a second drum, containing a standard matrix of higher density, and with a multiple radionuclide line source (Ba-133, Cs-137, Eu-152 and Am-241). These measurements represent a more challenging waste assay scenario, corresponding to potentially much larger assay uncertainties. Our results show how the assay uncertainty can be reduced, by careful application of AIGS, from relative values of the order of 100% to a few 10's of %. Furthermore, we demonstrate, through extended analysis of the test drum data, how an AIGS measurement program can be optimized to reduce the number of required measurement positions substantially. This paper describes these new results with comment on their importance and potential application for real waste assay projects. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Development of In-Situation Radioactivity Inspection System for Food Materials

The impacts on the ocean of releases of radionuclides from the Fukushima nuclear power plants remain unclear. Korean people worry about radioactive contamination of Japanese and Korean sea products. Radioactive contamination of processed foodstuffs, livestock, sea products, farm products imported from Japan and fishes caught in coastal oceans of Korea has become an important social issue. Recently, there are also needs of inspection system for monitoring of public meals such like school feedings of kindergarten, elementary/middle/high school and university. Radioactivity inspections of food materials have been executed manually with portable measuring instruments or at labs using their samples. But, it's very important the radioactivity inspection should be performed at the field of feeding facilities. To protect the health of people from radioactivity contained in Japanese marine products imported to Korea, a system to inspect radioactivity in real time has been developed. The system is to measure the radioactivity level of farm and marine products and public meals continuously and automatically at inspection sites of an agency checking radiation of imported foodstuffs or school. The performance test of NaI(Tl) detector was examined using the quantified Cs-137 source 10 Bq/kg, 30 Bq/kg, 50 Bq/kg, 300 Bq/kg and 900 Bq/kg at Korea Research Institute of Standards and Science(KRISS). Source was put in a box and radioactivity was measured in the middle of the box. First of all, Background was measured and calibration was performed using the Cs-137 300 Bq and Ba-133 3700 Bq for 60 minutes. After setting the background and calibration data, tests of the Cs-137 10, 30, 50, 300, 900 Bq/kg were executed for 10 minutes. A peak-shaped graph is shown at the location of 662 KeV (80∼100 channel). This is due to the gamma radiation energy with 662 KeV emitted by the Cs-137. Because through KRISS examination, the MDA (minimum detectable activity) is about 23 Bq/kg, it is reasonable Cs-137 10 Bq/kg cannot be measured. And in cases of Cs-137 300 Bq/kg and 900 Bq/kg, there are some peak movement on the graph. It can be adjusted by controlling gain or high voltage. The examination was identified through the performance test (Cs-137 10, 30, 50, 300, 900 Bq/kg) at KRISS. In order to increase the measurement efficiency of Cs-137 and the system performance, database will be built up based on radioactivity measurement results from 10 to 300 Bq/kg with the unit 10. Thus, Cs-137 concentration of food materials can be identified below the maximum permissible concentration of 100 Bq/kg on a basis of the spectrum characteristic of Cs-137. Also, anxiety about radioactive contamination of foods after the Fukushima nuclear accident will be eased and trust of the radioactive inspection is expected definitely. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗