Understanding the Radioactive Ingrowth and Decay of Naturally Occurring Radioactive Materials in the Environment: An Analysis of Produced Fluids from the Marcellus Shale.

PubMed

Nelson, Andrew W; Eitrheim, Eric S; Knight, Andrew W; May, Dustin; Mehrhoff, Marinea A; Shannon, Robert; Litman, Robert; Burnett, William C; Forbes, Tori Z; Schultz, Michael K

2015-07-01

The economic value of unconventional natural gas resources has stimulated rapid globalization of horizontal drilling and hydraulic fracturing. However, natural radioactivity found in the large volumes of "produced fluids" generated by these technologies is emerging as an international environmental health concern. Current assessments of the radioactivity concentration in liquid wastes focus on a single element-radium. However, the use of radium alone to predict radioactivity concentrations can greatly underestimate total levels. We investigated the contribution to radioactivity concentrations from naturally occurring radioactive materials (NORM), including uranium, thorium, actinium, radium, lead, bismuth, and polonium isotopes, to the total radioactivity of hydraulic fracturing wastes. For this study we used established methods and developed new methods designed to quantitate NORM of public health concern that may be enriched in complex brines from hydraulic fracturing wastes. Specifically, we examined the use of high-purity germanium gamma spectrometry and isotope dilution alpha spectrometry to quantitate NORM. We observed that radium decay products were initially absent from produced fluids due to differences in solubility. However, in systems closed to the release of gaseous radon, our model predicted that decay products will begin to ingrow immediately and (under these closed-system conditions) can contribute to an increase in the total radioactivity for more than 100 years. Accurate predictions of radioactivity concentrations are critical for estimating doses to potentially exposed individuals and the surrounding environment. These predictions must include an understanding of the geochemistry, decay properties, and ingrowth kinetics of radium and its decay product radionuclides.

Chemical Consequences of Radioactive Decay and their Biological Implications.

PubMed

DeJesus, Onofre T

2017-11-10

The chemical effects of radioactive decay arise from (1) transmutation, (2) formation of charged daughter nuclei, (3) recoil of the daughter nuclei, (4) electron "shakeoff" phenomenon and (5) vacancy cascade in decays via electron capture and internal conversion. This review aims to reiterate what has been known for a long time regarding the chemical consequences of radioactive decay and gives a historical perspective to the observations that led to their elucidation. The energetics of the recoil process in each decay mode is discussed in relation to the chemical bond between the decaying nucleus and the parent molecule. Special attention is given to the biological effects of the Auger process following decay by electron capture and internal conversion because of their possible utility in internal radiotherapy. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Detection of neutrinos, antineutrinos, and neutrino-like particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischbach, Ephraim

An apparatus for detecting the presence of a nuclear reactor by the detection of antineutrinos from the reactor can include a radioactive sample having a measurable nuclear activity level and a decay rate capable of changing in response to the presence of antineutrinos, and a detector associated with the radioactive sample. The detector is responsive to at least one of a particle or radiation formed by decay of the radioactive sample. A processor associated with the detector can correlate rate of decay of the radioactive sample to a flux of the antineutrinos to detect the reactor.

ATOMIC PHYSICS, AN AUTOINSTRUCTIONAL PROGRAM, VOLUME 3, SUPPLEMENT.

ERIC Educational Resources Information Center

DETERLINE, WILLIAM A.; KLAUS, DAVID J.

THE AUTOINSTRUCTIONAL MATERIALS IN THIS TEXT WERE PREPARED FOR USE IN AN EXPERIMENTAL STUDY, OFFERING SELF-TUTORING MATERIAL FOR LEARNING ATOMIC PHYSICS. THE TOPICS COVERED ARE (1) NUCLEAR BINDING ENERGY, (2) DISCOVERY OF RADIOACTIVITY, (3) RADIOACTIVE RADIATIONS, (4) ALPHA AND BETA DECAY, (5) BETA DECAY REACTIONS, (6) RADIOACTIVE DATING AND…

Update and evaluation of decay data for spent nuclear fuel analyses

NASA Astrophysics Data System (ADS)

Simeonov, Teodosi; Wemple, Charles

2017-09-01

Studsvik's approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL) and processed (ESTAR) sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources). Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

10 CFR 35.92 - Decay-in-storage.

Code of Federal Regulations, 2010 CFR

2010-01-01

... days for decay-in-storage before disposal without regard to its radioactivity if it— (1) Monitors byproduct material at the surface before disposal and determines that its radioactivity cannot be...

Low background screening capability in the UK

NASA Astrophysics Data System (ADS)

Ghag, Chamkaur

2015-08-01

Low background rare event searches in underground laboratories seeking observation of direct dark matter interactions or neutrino-less double beta decay have the potential to profoundly advance our understanding of the physical universe. Successful results from these experiments depend critically on construction from extremely radiologically clean materials and accurate knowledge of subsequent low levels of expected background. The experiments must conduct comprehensive screening campaigns to reduce radioactivity from detector components, and these measurements also inform detailed characterisation and quantification of background sources and their impact, necessary to assign statistical significance to any potential discovery. To provide requisite sensitivity for material screening and characterisation in the UK to support our rare event search activities, we have re-developed our infrastructure to add ultra-low background capability across a range of complementary techniques that collectively allow complete radioactivity measurements. Ultra-low background HPGe and BEGe detectors have been installed at the Boulby Underground Laboratory, itself undergoing substantial facility re-furbishment, to provide high sensitivity gamma spectroscopy in particular for measuring the uranium and thorium decay series products. Dedicated low-activity mass spectrometry instrumentation has been developed at UCL for part per trillion level contaminant identification to complement underground screening with direct U and Th measurements, and meet throughput demands. Finally, radon emanation screening at UCL measures radon background inaccessible to gamma or mass spectrometry techniques. With this new capability the UK is delivering half of the radioactivity screening for the LZ dark matter search experiment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghag, Chamkaur

Low background rare event searches in underground laboratories seeking observation of direct dark matter interactions or neutrino-less double beta decay have the potential to profoundly advance our understanding of the physical universe. Successful results from these experiments depend critically on construction from extremely radiologically clean materials and accurate knowledge of subsequent low levels of expected background. The experiments must conduct comprehensive screening campaigns to reduce radioactivity from detector components, and these measurements also inform detailed characterisation and quantification of background sources and their impact, necessary to assign statistical significance to any potential discovery. To provide requisite sensitivity for material screeningmore » and characterisation in the UK to support our rare event search activities, we have re-developed our infrastructure to add ultra-low background capability across a range of complementary techniques that collectively allow complete radioactivity measurements. Ultra-low background HPGe and BEGe detectors have been installed at the Boulby Underground Laboratory, itself undergoing substantial facility re-furbishment, to provide high sensitivity gamma spectroscopy in particular for measuring the uranium and thorium decay series products. Dedicated low-activity mass spectrometry instrumentation has been developed at UCL for part per trillion level contaminant identification to complement underground screening with direct U and Th measurements, and meet throughput demands. Finally, radon emanation screening at UCL measures radon background inaccessible to gamma or mass spectrometry techniques. With this new capability the UK is delivering half of the radioactivity screening for the LZ dark matter search experiment.« less

[Current status on storage, processing and risk communication of medical radioactive waste in Japan].

PubMed

Watanabe, Hiroshi; Yamaguchi, Ichiro; Kida, Tetsuo; Hiraki, Hitoshi; Fujibuchi, Toshioh; Maehara, Yoshiaki; Tsukamoto, Atsuko; Koizumi, Mitsue; Kimura, Yumi; Horitsugi, Genki

2013-03-01

Decay-in-storage for radioactive waste including that of nuclear medicine has not been implemented in Japan. Therefore, all medical radioactive waste is collected and stored at the Japan Radioisotope Association Takizawa laboratory, even if the radioactivity has already decayed out. To clarify the current situation between Takizawa village and Takizawa laboratory, we investigated the radiation management status and risk communication activities at the laboratory via a questionnaire and site visiting survey in June 2010. Takizawa laboratory continues to maintain an interactive relationship with local residents. As a result, Takizawa village permitted the acceptance of new medical radioactive waste containing Sr-89 and Y-90. However, the village did not accept any non-medical radioactive waste such as waste from research laboratories. To implement decay-in-storage in Japan, it is important to obtain agreement with all stakeholders. We must continue to exert sincere efforts to acquire the trust of all stakeholders.

DECAY OF INCORPORATED RADIOACTIVE PHOSPHORUS DURING REPRODUCTION OF BACTERIOPHAGE T2

PubMed Central

Stent, Gunther S.

1955-01-01

The multiplication of vegetative T2 bacteriophage in B/r bacteria has been followed by studying the lethal effects of decay of incorporated radiophosphorus P32 at various stages of the eclipse period. Experiment I. Non-radioactive B/r bacteria were infected with highly radioactive (i.e. P32-unstable) T2 and infection allowed to proceed at 37°C. for various numbers of minutes before freezing the infected cells and storing them in liquid nitrogen. The longer development had been allowed to proceed at 37°C. before freezing, the slower the inactivation of the frozen infective centers by P32 decay. Samples which were frozen after incubation for 9 minutes were completely stable. Experiment II. Radioactive B/r bacteria in radioactive growth medium were infected with non-radioactive (i.e. stable) T2 and incubated for various lengths of time before being frozen and stored in liquid nitrogen, like those of Experiment I. In this case, the infective centers were stable to P32 decay as long as they were frozen before the end of the eclipse period. The T2 progeny phages issuing from the infected bacteria were P32-unstable. Experiment III. Radioactive B/r bacteria in radioactive medium were infected with radioactive (i.e. P32-unstable) T2 and otherwise incubated and frozen like those of the first two experiments. In this case, the same progressive stabilization, of the infective centers towards inactivation by P32 decay was observed as that found in Experiment I. The ability to yield infective progeny of infected bacteria incubated for 10 minutes at 37°C. before freezing could no longer be destroyed by P32 decay. The progeny issuing from the infected cells were as unstable as the parental phage. These results could be explained by one of three general hypotheses. As vegetative phage begins to multiply, it is possible that: (a) there is a high probability that any part of the vegetative phage already duplicated can be saved after its destruction by P32 decay through a process analogous to multiplicity reactivation or, (b) there occurs a change in state of the deoxyribonucleic acid (DNA) preliminary to or in the course of its replication that renders it refractory to destruction by P32 decay, or, finally (c) there occurs a transfer of the genetic factors from the DNA of the infecting phage to another substance not sensitive to destruction by P32 decay. PMID:13242767

Spatial and Time Coincidence Detection of the Decay Chain of Short-Lived Radioactive Nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Granja, Carlos; Jakubek, Jan; Platkevic, Michal

The quantum counting position sensitive pixel detector Timepix with per-pixel energy and time resolution enables to detect radioactive ions and register the consecutive decay chain by simultaneous position-and time-correlation. This spatial and timing coincidence technique in the same sensor is demonstrated by the registration of the decay chain {sup 8}He{yields}{sup {beta} 8}Li and {sup 8}Li{yields}{sup {beta}-} {sup 8}Be{yields}{alpha}+{alpha} and by the measurement of the {beta} decay half-lives. Radioactive ions, selectively obtained from the Lohengrin fission fragment spectrometer installed at the High Flux Reactor of the ILL Grenoble, are delivered to the Timepix silicon sensor where decays of the implanted ionsmore » and daughter nuclei are registered and visualized. We measure decay lifetimes in the range {>=}{mu}s with precision limited just by counting statistics.« less

ELECTRONIC ANALOG COMPUTER FOR DETERMINING RADIOACTIVE DISINTEGRATION

DOEpatents

Robinson, H.P.

1959-07-14

A computer is presented for determining growth and decay curves for elements in a radioactive disintegration series wherein one unstable element decays to form a second unstable element or isotope, which in turn forms a third element, etc. The growth and decay curves of radioactive elements are simulated by the charge and discharge curves of a resistance-capacitance network. Several such networks having readily adjustable values are connected in series with an amplifier between each successive pair. The time constant of each of the various networks is set proportional to the half-life of a corresponding element in the series represented and the charge and discharge curves of each of the networks simulates the element growth and decay curve.

Insights.

ERIC Educational Resources Information Center

Bogner, Donna, Ed.

1988-01-01

Describes two methods to teach radioactive decay to secondary students with wide ranging abilities. Activities are designed to follow classroom discussions of atomic structure, transmutation, half life, and nuclear decay. Includes "The Tasmanian Empire: A Radioactive Dating Activity" and an exercise to teach concepts of half life without…

Source term evaluation model for high-level radioactive waste repository with decay chain build-up.

PubMed

Chopra, Manish; Sunny, Faby; Oza, R B

2016-09-18

A source term model based on two-component leach flux concept is developed for a high-level radioactive waste repository. The long-lived radionuclides associated with high-level waste may give rise to the build-up of activity because of radioactive decay chains. The ingrowths of progeny are incorporated in the model using Bateman decay chain build-up equations. The model is applied to different radionuclides present in the high-level radioactive waste, which form a part of decay chains (4n to 4n + 3 series), and the activity of the parent and daughter radionuclides leaching out of the waste matrix is estimated. Two cases are considered: one when only parent is present initially in the waste and another where daughters are also initially present in the waste matrix. The incorporation of in situ production of daughter radionuclides in the source is important to carry out realistic estimates. It is shown that the inclusion of decay chain build-up is essential to avoid underestimation of the radiological impact assessment of the repository. The model can be a useful tool for evaluating the source term of the radionuclide transport models used for the radiological impact assessment of high-level radioactive waste repositories.

Nuclear Data Sheets for A = 94

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abriola, D.; Sonzogni, A.A.

Experimental data on ground- and excited-state properties for all known nuclei with mass number A = 94 have been compiled and evaluated. States populated in radioactive decay, as well as in nuclear reactions, have been considered. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are given. The Hager-Seltzer internal conversion coefficients are listed for gamma rays of known multipolarity. This work supersedes the 1992 evaluation by J.K. Tuli (1992Tu02). Since 1992, many articles have been published which were incorporated in this evaluation. In summary, high-spin data using large arrays of Ge detectors have beenmore » obtained for {sup 94}Kr (2000Rz02), {sup 94}Sr (1995Ha20), {sup 94}Zr (2002Fo03,2005Pa48), {sup 94}Nb (2000Ma63), {sup 94}Mo (1998Kh04), {sup 94}Tc (2000Gh01), {sup 94}Ru (1994Ju03,1994Ro08), {sup 94}Rh (1994Ar33), and {sup 94}Pd (2003Ma24). A new isomer was observed in {sup 91}999Ge01). The low-spin levels in {sup 98}Mo were systematically studied using a variety of experimental techniques (2003Fr02). Considerable effort was spent investigating the decay of {sup 94}Ag and the levels of {sup 94}Pd (2006Mu03,2005Mu15,2004BaZY,2004Pl01,2002La18), in particular, the (21+) level in {sup 94}Ag is the first level observed to undergo both single and double proton radioactivity.« less

In sæcula sæculorum: A lab activity to create with students a radioactive secular equilibrium model⋆

NASA Astrophysics Data System (ADS)

Santostasi, D.

2017-03-01

The teaching of radioactivity in the high school is often difficult to implement, especially from an experimental point of view. In this paper an activity based on a laboratory experiment on radioactivity is presented. The activity was proposed to high school students in their fourth year of studies attending the summer internship organized by the University of Pavia at the Department of Physics. The experiement concerns the radon decay chain, and in particular the measurement of the activity of 214Bi , both in absence and in presence of its progenitor 222Rn . This way it is possible to observe two different decay curves: the first provides a 214Bi decay constant in agreement with the theoretical one, whereas the trend of the second one can be understood only through the hypothesis of secular equilibrium with 222Rn . Using an engaging and interesting game with dice, a model of radioactive decay was developed and performed with students divided in small groups.

MEASUREMENT OF TIME INTERVALS FOR TIME CORRELATED RADIOACTIVE DECAY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindeman, H.; Mornel, E.; Galil, U.

1960-11-01

The distribution of time intervals between successive counts was measured for radioactive decay in the thorium series. The measurements showed that the classical Marsden-Barratt law does not apply to this case of timecorrelated decay. They appeared, however, to be in agreement with the theory of Lindeman-Rosen, taking into account the fact that the counter receives only the radiation emitted in a solid angle near to 2 pi . (auth)

Influence of radioactivity on surface charging and aggregation kinetics of particles in the atmosphere.

PubMed

Kim, Yong-Ha; Yiacoumi, Sotira; Lee, Ida; McFarlane, Joanna; Tsouris, Costas

2014-01-01

Radioactivity can influence surface interactions, but its effects on particle aggregation kinetics have not been included in transport modeling of radioactive particles. In this research, experimental and theoretical studies have been performed to investigate the influence of radioactivity on surface charging and aggregation kinetics of radioactive particles in the atmosphere. Radioactivity-induced charging mechanisms have been investigated at the microscopic level, and heterogeneous surface potential caused by radioactivity is reported. The radioactivity-induced surface charging is highly influenced by several parameters, such as rate and type of radioactive decay. A population balance model, including interparticle forces, has been employed to study the effects of radioactivity on particle aggregation kinetics in air. It has been found that radioactivity can hinder aggregation of particles because of similar surface charging caused by the decay process. Experimental and theoretical studies provide useful insights into the understanding of transport characteristics of radioactive particles emitted from severe nuclear events, such as the recent accident of Fukushima or deliberate explosions of radiological devices.

Alphas and surface backgrounds in liquid argon dark matter detectors

NASA Astrophysics Data System (ADS)

Stanford, Christopher J.

Current observations from astrophysics indicate the presence of dark matter, an invisible form of matter that makes up a large part of the mass of the universe. One of the leading theories for dark matter is that it is made up of Weakly Interacting Massive Particles (WIMPs). One of the ways we try to discover WIMPs is by directly detecting their interaction with regular matter. This can be done using a scintillator such as liquid argon, which gives off light when a particle interacts with it. Liquid argon (LAr) is a favorable means of detecting WIMPs because it has an inherent property that enables a technique called pulse-shape discrimination (PSD). PSD can distinguish a WIMP signal from the constant background of electromagnetic signals from other sources, like gamma rays. However, there are other background signals that PSD is not as capable of rejecting, such as those caused by alpha decays on the interior surfaces of the detector. Radioactive elements that undergo alpha decay are introduced to detector surfaces during construction by radon gas that is naturally present in the air, as well as other means. When these surface isotopes undergo alpha decay, they can produce WIMP-like signals in the detector. We present here two LAr experiments. The first (RaDOSE) discovered a property of an organic compound that led to a technique for rejecting surface alpha decays in LAr detectors with high efficiency. The second (DarkSide-50) is a dark matter experiment operated at LNGS in Italy and is the work of an international collaboration. A detailed look is given into alpha decays and surface backgrounds present in the detector, and projections are made of alpha-related backgrounds for 500 live days of data. The technique developed with RaDOSE is applied to DarkSide-50 to determine its effectiveness in practice. It is projected to suppress the surface background in DarkSide-50 by more than a factor of 1000.

Radioactive liquid wastes discharged to ground in the 200 Areas during 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mirabella, J.E.

An overall summary is presented giving the radioactive liquid wastes discharged to ground during 1976 and since startup (for both total and decayed depositions) within the Production and Waste Management Division control zone (200 Area plateau). Overall summaries are also presented for 200 East Area and for 200 West Area. The data contain an estimate of the radioactivity discharged to individual ponds, cribs and specific retention sites within the Production and Waste Management Division during 1976 and from startup through December 31, 1976; an estimate of the decayed activities from startup through 1976; the location and reference drawings of eachmore » disposal site; and the usage dates of each disposal site. The estimates for the radioactivity discharged and for decayed activities dicharged from startup through December 31, 1976 are based upon Item 4 of the Bibliography. The volume of liquid discharged to the ponds also includes major nonradioactive streams. The wastes discharged during 1976 to each active disposal site are detailed on a month-to-month basis, along with the monthly maximum concentration and average concentration data. An estimate of the radioactivity discharged to each active site along with the remaining decayed activities is given.« less

Simplifying the Mathematical Treatment of Radioactive Decay

ERIC Educational Resources Information Center

Auty, Geoff

2011-01-01

Derivation of the law of radioactive decay is considered without prior knowledge of calculus or the exponential series. Calculus notation and exponential functions are used because ultimately they cannot be avoided, but they are introduced in a simple way and explained as needed. (Contains 10 figures, 1 box, and 1 table.)

An experiment on radioactive equilibrium and its modelling using the ‘radioactive dice’ approach

NASA Astrophysics Data System (ADS)

Santostasi, Davide; Malgieri, Massimiliano; Montagna, Paolo; Vitulo, Paolo

2017-07-01

In this article we describe an educational activity on radioactive equilibrium we performed with secondary school students (17-18 years old) in the context of a vocational guidance stage for talented students at the Department of Physics of the University of Pavia. Radioactive equilibrium is investigated experimentally by having students measure the activity of 214Bi from two different samples, obtained using different preparation procedures from an uraniferous rock. Students are guided in understanding the mathematical structure of radioactive equilibrium through a modelling activity in two parts. Before the lab measurements, a dice game, which extends the traditional ‘radioactive dice’ activity to the case of a chain of two decaying nuclides, is performed by students divided into small groups. At the end of the laboratory work, students design and run a simple spreadsheet simulation modelling the same basic radioactive chain with user defined decay constants. By setting the constants to realistic values corresponding to nuclides of the uranium decay chain, students can deepen their understanding of the meaning of the experimental data, and also explore the difference between cases of non-equilibrium, transient and secular equilibrium.

Poster — Thur Eve — 41: Considerations for Patients with Permanently Implant Radioactive Sources Requiring Unrelated Surgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basran, P. S; Beckham, WA; Baxter, P

Permanent implant of sealed radioactive sources is an effective technique for treating cancer. Typically, the radioactive sources are implanted in and near the disease, depositing dose locally over several months. There may be instances where these patients must undergo unrelated surgical procedures when the radioactive material remains active enough to pose risks. This work explores these risks, discusses strategies to mitigate those risks, and describes a case study for a permanent I-125 prostate brachytherapy implant patient who developed colo-rectal cancer and required surgery 6 months after brachytherapy. The first consideration is identifying the risk from unwarranted radiation to the patientmore » and staff before, during, and after the surgical procedure. The second is identifying the risk the surgical procedure may have on the efficacy of the brachytherapy implant. Finally, there are considerations for controlling for radioactive substances from a regulatory perspective. After these risks are defined, strategies to mitigate those risks are considered. These strategies may include applying the concepts of ALARA, the use of protective equipment and developing a best practice strategy with the operating room team. We summarize this experience with some guidelines: If the surgical procedure is near (ex: 5 cm) of the implant; and, the surgical intervention may dislodge radioisotopes enough to compromise treatment or introduces radiation safety risks; and, the radioisotope has not sufficiently decayed to background levels; and, the surgery cannot be postponed, then a detailed analysis of risk is advised.« less

Exploring Radioactive Decay and Geochronology through Hydrostatic Principles

NASA Astrophysics Data System (ADS)

Claiborne, L. L.; Miller, C. F.

2008-12-01

One of the most essential tools to unraveling Earth's history and the processes involved in shaping our planet is an understanding of deep time and the timescales involved in geologic processes. The primary process that allows quantification of this history is radioactive decay of unstable isotopes within earth materials, and as one of the most essential tools in geology, this concept is taught at all levels of geoscience education. The concept of radioactive decay contains nuances that are often lost on students during lectures, and students often express low confidence in their comprehension of the concept. The goal of this laboratory activity is for students to understand radioactive decay including what controls it, how it proceeds and what information it provides, along with developing higher level scientific skills including making observations and predictions, and creating and interpreting quantitative graphical representations of data. The activity employs graduated beakers, shampoo, and stopwatches. Students pour shampoo put into an upper beaker (representing the parent isotope) with a hole in the base and allow it to flow into a lower beaker (representing the daughter isotope). Students measure changes in liquid depth with time, relating this to the amount of decay and its dependence on the amount of parent available (depth of liquid) and the decay constant (area of the hole in the beaker). Several beakers with varying sized holes illustrate variations specific to the different parent isotopes. They then explore graphical representations of their "decay" data, discovering for themselves which kinds of plots yield the equations and constants that control the decay process and the derived quantity of the "half-life", and are therefore the most useful. Making their own measurements, creating graphs, and then calculating these fundamental quantities is both enlightening and empowering. An advanced variation of this experiment involves students predicting the results and/or designing an experiment to address complex decay chains, where the daughter products are radioactive themselves. This permits them to investigate connections between 'activity' and equilibrium and to understand how disequilibrium can develop and be used for dating. In order to evaluate the success of the activity, each student participates in pre and post assessment including stating their confidence in their understanding of the concept.

The Weak Nuclear Force: Quantum Chameleon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Don

Radioactive decay is the transmutation of one subatomic particle into another. In most instances, what happens is that existing particles move to new configurations. However in radioactive decays using the weak force, a particular kind of particle disappears and is replaced by a completely different particle. In this video, Fermilab’s Dr. Don Lincoln talks about how it all works and even describes a type of decay that has never been observed and, if it were observed, it would require the textbooks be rewritten.

Radioactive decay of the late-time light curves of GRB-SNe

NASA Astrophysics Data System (ADS)

Misra, Kuntal; Fruchte, Andrew Steven

2018-04-01

We present the late-time Hubble Space Telescope observations of two GRB associated supernovae, GRB 030329/SN 2003dh and XRF 060218/SN 2006aj. Using the multi-color data upto ˜ 320 days after the burst, we constrain the late-time decay nature of these supernovae. The decay rates of SN 2003dh are steeper than SN 2006aj. A comparison with two other GRB supernovae, GRB 980425/SN 1998bw and the supernova associated with XRF 020903, shows that the decay rates of SN 2003dh are similar to XRF 020903 and those of SN 2006aj are similar to SN 1998bw. The late-time decay rates are steeper than the 56Co?56Fe radioactive decay rate (0.0098 mag day-1) indicating that there is some leakage of gamma-rays.

Forensic microanalysis of Manhattan Project legacy radioactive wastes in St. Louis, MO.

PubMed

Kaltofen, Marco; Alvarez, Robert; Hixson, Lucas W

2018-06-01

Radioactive particulate matter (RPM) in St Louis, MO, area surface soils, house dusts and sediments was examined by scanning electron microscopy with energy dispersive X-ray analysis. Analyses found RPM containing 238 U and decay products (up to 46 wt%), and a distinct second form of RPM containing 230 Th and decay products (up to 15.6 wt%). The SEM-EDS analyses found similar RPM in Manhattan Project-era radioactive wastes and indoor dusts in surrounding homes. Copyright © 2018 Elsevier Ltd. All rights reserved.

On the Nature of the Cherdyntsev-Chalov Effect

NASA Astrophysics Data System (ADS)

Timashev, S. F.

2018-06-01

It is shown that the Cherdyntsev-Chalov effect, usually presented as the separation of even isotopes of uranium upon their transition from the solid to the liquid phase, can include initiated acceleration of the radioactive decay of uranium-238 nuclei during the formation of cracks in geologically (seismic and volcanically) active zones of the Earth's crust. The fissuring of the solid-phase medium leads to an increase in mechanical tensile stress and the emergence of strong local electric fields, resulting in the injection of chemical-scale high-energy electrons into the aqueous phase of the cracks. Under these conditions, the e - catalytic decay of uranium-238 nucleus studied earlier can occur during the formation of metastable protactinium-238 nuclei with locally distorted nucleon structure, which subequently undergo β-decay with the formation of thorium-234 and helium-4 nuclei as products of the fission of the initial uranium-238 nucleus with a characteristic period of several years. The observed increased activity of uranium-234 nuclei that form during the subsequent β-decay of thorium and then protactinium is associated with the initiated fission of uranium-238. The possibility is discussed of developing thermal power by using existing wastes from uranium production that contain uranium-238 to activate this isotope through the mechanochemical processing of these wastes in aqueous media with the formation of 91 238 Pa isu , the half-life of which is several years.

Asymptotic Analysis of Time-Dependent Neutron Transport Coupled with Isotopic Depletion and Radioactive Decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brantley, P S

2006-09-27

We describe an asymptotic analysis of the coupled nonlinear system of equations describing time-dependent three-dimensional monoenergetic neutron transport and isotopic depletion and radioactive decay. The classic asymptotic diffusion scaling of Larsen and Keller [1], along with a consistent small scaling of the terms describing the radioactive decay of isotopes, is applied to this coupled nonlinear system of equations in a medium of specified initial isotopic composition. The analysis demonstrates that to leading order the neutron transport equation limits to the standard time-dependent neutron diffusion equation with macroscopic cross sections whose number densities are determined by the standard system of ordinarymore » differential equations, the so-called Bateman equations, describing the temporal evolution of the nuclide number densities.« less

A calculation model to half-life estimate of two-proton radioactive decay process

NASA Astrophysics Data System (ADS)

Tavares, O. A. P.; Medeiros, E. L.

2018-04-01

Partial half-life of the radioactive decay by the two-proton emission mode has been estimated for proton-rich nuclei of mass number 18 < A < 68 by a model based on the quantum mechanical tunneling mechanism through a potential barrier. The Coulomb, centrifugal and overlapping contributions to the barrier have been considered within the spherical nucleus approximation. The present calculation method has been shown to be adequate in reproducing the existing experimental half-life data for 19Mg, 45Fe, 48Ni, and 54Zn 2p-emitter nuclides within a factor six. For 67Kr parent nucleus the calculated partial 2p-decay half-life has been found to be ten times greater than the recent, unique measured value at RIKEN Nishina Center. Prediction for new, yet unmeasured cases of two-proton radioactivity are also reported.

Puzzling Two-Proton Decay of 67Kr

NASA Astrophysics Data System (ADS)

Wang, S. M.; Nazarewicz, W.

2018-05-01

Ground-state two-proton (2 p ) radioactivity is a rare decay mode found in a few very proton-rich isotopes. The 2 p decay lifetime and properties of emitted protons carry invaluable information on nuclear structure in the presence of a low-lying proton continuum. The recently measured 2 p decay of 67Kr turned out to be unexpectedly fast. Since 67Kr is expected to be a deformed system, we investigate the impact of deformation effects on the 2 p radioactivity. We apply the recently developed Gamow coupled-channel framework, which allows for a precise description of three-body systems in the presence of rotational and vibrational couplings. This is the first application of a three-body approach to a two-nucleon decay from a deformed nucleus. We show that deformation couplings significantly increase the 2 p decay width of 67Kr; this finding explains the puzzling experimental data. The calculated angular proton-proton correlations reflect a competition between 1 p and 2 p decay modes in this nucleus.

Study of ^{14}C Cluster Decay Half-Lives of Heavy Deformed Nuclei

NASA Astrophysics Data System (ADS)

Shamami, S. Rahimi; Pahlavani, M. R.

2018-01-01

A theoretical model based on deformed Woods-Saxon, Coulomb and centrifugal terms are constructed to evaluate the half-lives for the cluster radioactivity of various super heavy nuclei. Deformation have been applied on all parts of their potential containing nuclear barrier for cluster decay. Also, both parent and daughter nuclei are considered to be deformed. The calculated results of ^{14}C cluster radioactivity half-lives are compared with available experimental data. A satisfactory agreement between theoretical and measured data is achieved. Also, obtained half-lives for each decay family is agreed with Geiger-Nuttall law.

Measurement of Radioactive Contamination in the High-Resistivity Silicon CCDs of the DAMIC Experiment

DOE PAGES

Aguilar-Arevalo, A.

2015-08-25

We present measurements of radioactive contamination in the high-resistivity silicon charge-coupled devices (CCDs) used by the DAMIC experiment to search for dark matter particles. Novel analysis methods, which exploit the unique spatial resolution of CCDs, were developed to identify α and β particles. Uranium and thorium contamination in the CCD bulk was measured through α spectroscopy, with an upper limit on the 238U ( 232Th) decay rate of 5 (15) kg -1 d -1 at 95% CL. We also searched for pairs of spatially correlated electron tracks separated in time by up to tens of days, as expected from 32Simore » – 32P or 210Pb – 210Bi sequences of b decays. The decay rate of 32Si was found to be 80 +110 -65 (95% CI). An upper limit of ~35 kg -1 d -1 (95% CL) on the 210Pb decay rate was obtained independently by α spectroscopy and the β decay sequence search. Furthermore, these levels of radioactive contamination are sufficiently low for the successful operation of CCDs in the forthcoming 100 g DAMIC detector.« less

The Decay Data Evaluation Project (DDEP) and the JEFF-3.3 radioactive decay data library: Combining international collaborative efforts on evaluated decay data

NASA Astrophysics Data System (ADS)

Kellett, Mark A.; Bersillon, Olivier

2017-09-01

The Decay Data Evaluation Project (DDEP), is an international collaboration of decay data evaluators formed with groups from France, Germany, USA, China, Romania, Russia, Spain and the UK, mainly from the metrology community. DDEP members have evaluated over 220 radionuclides, following an agreed upon methodology, including a peer review. Evaluations include all relevant parameters relating to the nuclear decay and the associated atomic processes. An important output of these evaluations are recommendations for new measurements, which can serve as a basis for future measurement programmes. Recently evaluated radionuclides include: 18F, 59Fe, 82Rb, 82Sr, 88Y, 90Y, 89Zr, 94mTc, 109Cd, 133Ba, 140Ba, 140La, 151Sm and 169Er. The DDEP recommended data have recently been incorporated into the JEFF-3.3 Radioactive Decay Data Library. Other sources of nuclear data include 900 or so radionuclides converted from the Evaluated Nuclear Structure Data File (ENSDF), 500 from two UK libraries (UKPADD6.12 and UKHEDD2.6), the IAEA Actinide Decay Data Library, with the remainder converted from the NUBASE evaluation of nuclear properties. Mean decay energies for a number of radionuclides determined from total absorption gamma-ray spectroscopy (TAGS) have also been included, as well as more recent European results from TAGS measurements performed at the University of Jyväskylä by groups from the University of Valencia, Spain and SUBATECH, the University of Nantes, France. The current status of the DDEP collaboration and the JEFF Radioactive Decay Data Library will be presented. Note to the reader: the pdf file has been changed on September 22, 2017.

Siphons, Water Clocks, Cooling Coffee, and Leaking Capacitors: Classroom Activities and a Few Equations to Help Students Understand Radioactive Decay and Other Exponential Processes

ERIC Educational Resources Information Center

Brady, John B.

2009-01-01

Although an understanding of radiometric dating is central to the preparation of every geologist, many students struggle with the concepts and mathematics of radioactive decay. Physical demonstrations and hands-on experiments can be used to good effect in addressing this teaching conundrum. Water, heat, and electrons all move or flow in response…

The First Hours of the GW170817 Kilonova and the Importance of Early Optical and Ultraviolet Observations for Constraining Emission Models

NASA Astrophysics Data System (ADS)

Arcavi, Iair

2018-03-01

The kilonova associated with GW170817 displayed early blue emission, which has been interpreted as a signature of either radioactive decay in low-opacity ejecta, relativistic boosting of radioactive decay in high-velocity ejecta, the cooling of material heated by a wind or by a “cocoon” surrounding a jet, or a combination thereof. Distinguishing between these mechanisms is important for constraining the ejecta components and their parameters, which tie directly into the physics we can learn from these events. I compile published ultraviolet, optical, and infrared light curves of the GW170817 kilonova and examine whether the combined data set can be used to distinguish between early-emission models. The combined optical data show an early rise consistent with radioactive decay of low-opacity ejecta as the main emission source, but the subsequent decline is fit well by all models. A lack of constraints on the ultraviolet flux during the first few hours after discovery allows for both radioactive decay and other cooling mechanisms to explain the early bolometric light curve. This analysis demonstrates that early (few hours after merger) high-cadence optical and ultraviolet observations will be critical for determining the source of blue emission in future kilonovae.

Role of shell corrections in the phenomenon of cluster radioactivity

NASA Astrophysics Data System (ADS)

Kaur, Mandeep; Singh, Bir Bikram; Sharma, Manoj K.

2018-05-01

The detailed investigation has been carried out to explore the role of shell corrections in the decay of various radioactive parent nuclei in trans-lead region, specifically, which lead to doubly magic 208Pb daughter nucleus through emission of clusters such as 14C, 18,20O, 22,24,26Ne, 28,30 Mg and 34S i. The fragmentation potential comprises of binding energies (BE), Coulomb potential (Vc) and nuclear or proximity potential (VP) of the decaying fragments (or clusters). It is relevant to mention here that the contributions of VLDM (T=0) and δU (T=0) in the BE have been analysed within the Strutinsky renormanlization procedure. In the framework of quantum mechanical fragmentation theory (QMFT), we have investigated the above mentioned cluster decays with and without inclusion of shell corrections in the fragmentation potential for spherical as well as non-compact oriented nuclei. We find that the experimentally observed clusters 14C, 18,20O, 22,24,26 Ne, 28,30 Mg and 34Si having doubly magic 208 Pb daughter nucleus are not strongly minimized, they do so only after the inclusion of shell corrections in the fragmentation potential. The nuclear structure information carried by the shell corrections have been explored via these calculations, within the collective clusterisation process of QMFT, in the study of ground state decay of radioactive nuclei. The role of different parts of fragmentation potentials such as VLDM, δU, Vc and Vp is dually analysed for better understanding of radioactive cluster decay.

Wait for It: Post-supernova Winds Driven by Delayed Radioactive Decays

NASA Astrophysics Data System (ADS)

Shen, Ken J.; Schwab, Josiah

2017-01-01

In most astrophysical situations, the radioactive decay of {}56{Ni} to {}56{Co} occurs via electron capture with a fixed half-life of 6.1 days. However, this decay rate is significantly slowed when the nuclei are fully ionized because K-shell electrons are unavailable for capture. In this paper, we explore the effect of these delayed decays on white dwarfs (WDs) that may survive Type Ia and Type Iax supernovae (SNe Ia and SNe Iax). The energy released by the delayed radioactive decays of {}56{Ni} and {}56{Co} drives a persistent wind from the surviving WD’s surface that contributes to the late-time appearance of these SNe after emission from the bulk of the SN ejecta has faded. We use the stellar evolution code MESA to calculate the hydrodynamic evolution and resulting light curves of these winds. Our post-SN Ia models conflict with late-time observations of SN 2011fe, but uncertainties in our initial conditions prevent us from ruling out the existence of surviving WD donors. Much better agreement with observations is achieved with our models of post-SN Iax bound remnants, providing evidence that these explosions are due to deflagrations in accreting WDs that fail to completely unbind the WDs. Future radiative transfer calculations and wind models utilizing simulations of explosions for more accurate initial conditions will extend our study of radioactively powered winds from post-SN surviving WDs and enable their use as powerful discriminants among the various SN Ia and SN Iax progenitor scenarios.

The Distribution of Heat-Producing Radioactive Elements in the Deep Earth

NASA Astrophysics Data System (ADS)

Chidester, Bethany A.

The Earth is a heat engine, where large differences in temperature between the interior and the surface drive large-scale movement that manifests as plate tectonics and the geomagnetic field that protects us from the Sun's harmful charged particles. Decay of the long-lived radioactive elements U, Th, and K is expected to contribute as much as 45% of the current heat production in the Earth, and that heat production was five times higher early in Earth's history. It is unclear how this heat source affects the thermal and dynamic evolution of the Earth's core and mantle and how that contribution has changed over geologic time. This dissertation addresses this problem in several different ways. This work represents the first high-pressure, high-temperature metal-silicate partitioning experiments for U, Th, and K in the laser-heated diamond anvil cell at conditions relevant to core formation. A chemical model is developed using parameterization of these partitioning data to constrain the concentrations of each of these elements in the core. Using a numerical calculation, it is then determined how that radioactive heat would contribute to the core's energy and entropy budget through time. One finds that, despite its strong lithophile nature at the surface, U partitions significantly into the metallic phase at increasing temperatures. This may be due to a decrease in U valence from 4+ to 2+ in high-pressure silicate melts, which our data supports. However, K and Th do not exhibit a similar change in behavior at these conditions, and this may drive fractionation between U and Th in the deep mantle. At the most extreme conditions of core formation, enough U could exist in the core to produce up to 4.4 TW of heat 4.5 billion years ago. Potassium could produce much less heat than U early on (< 1 TW), and due to its short half-life, would have decayed away much faster. While this energy source is significantly greater than was previously thought to be possible, it is likely not enough to explain the presence of the geomagnetic field early in Earth's history. I have also completed a synchrotron-based study to determine the phase behavior and equations of state of UO2 and ThO2. ThO 2 undergoes a phase transition from the fluorite- type structure (thorianite) that is stable at ambient conditions to the previously identified cotunnite-type structure around 19 GPa and 1500 K. It remains in the cotunnite-type phase up to 60 GPa and 2500 K. UO2 undergoes several solid phase transitions at high pressure. The fluorite-type (uraninite) to cotunnite-type transition occurs around 20 GPa above 1100 K. At around 35 GPa, a new phase emerges; this phase has been indexed to a tetragonal crystal structure. Finally, at 80 GPa and above, UO2 undergoes another phase transition or dissociates into two separate oxides. This understanding of the phase behavior of the simplest actinide-bearing minerals provides insight into the mineralogical hosts for these radioactive elements, as well as other large cations, in the Earth's deep mantle.

Project Physics Text 6, The Nucleus.

ERIC Educational Resources Information Center

Harvard Univ., Cambridge, MA. Harvard Project Physics.

Nuclear physics fundamentals are presented in this sixth unit of the Project Physics text for use by senior high students. Included are discussions of radioactivity, taking into account Bacquerel's discovery, radioactive elements, properties of radiations, radioactive transformations, decay series, and half-lives. Isotopes are analyzed in…

Nuclide radioactive decay data uncertainties library

NASA Astrophysics Data System (ADS)

Barabanova, D. S.; Zherdev, G. M.

2017-01-01

The results of the developing the library of uncertainties of radioactive decay data in the ABBN data library format are described. Different evaluations of uncertainties were compared and their effects on the results of calculations of residual energy release were determined using the test problems and experiment. Tables were generated in the ABBN format with the data obtained on the basis of libraries in ENDF-6 format. 3821 isotopes from the ENDF/B-7 data library, 3852 isotopes from the JEFF-3.11 data library and 1264 isotopes from the JENDL-4.0 data library were processed. It was revealed that the differences in the evaluations accepted in different decay data libraries are not so big, although they sometimes exceed the uncertainties assigned to the data in the ENDF/B-7 and JEFF-3.11 libraries, which as a rule, they agree with each other. On the basis of developed method it is supposed to create a library of data uncertainties for radioactive decay within the constant data system in FSUE RFNC-VNIIEF with its further connection with CRYSTAL module.

ANITA-2000 activation code package - updating of the decay data libraries and validation on the experimental data of the 14 MeV Frascati Neutron Generator

NASA Astrophysics Data System (ADS)

Frisoni, Manuela

2016-03-01

ANITA-2000 is a code package for the activation characterization of materials exposed to neutron irradiation released by ENEA to OECD-NEADB and ORNL-RSICC. The main component of the package is the activation code ANITA-4M that computes the radioactive inventory of a material exposed to neutron irradiation. The code requires the decay data library (file fl1) containing the quantities describing the decay properties of the unstable nuclides and the library (file fl2) containing the gamma ray spectra emitted by the radioactive nuclei. The fl1 and fl2 files of the ANITA-2000 code package, originally based on the evaluated nuclear data library FENDL/D-2.0, were recently updated on the basis of the JEFF-3.1.1 Radioactive Decay Data Library. This paper presents the results of the validation of the new fl1 decay data library through the comparison of the ANITA-4M calculated values with the measured electron and photon decay heats and activities of fusion material samples irradiated at the 14 MeV Frascati Neutron Generator (FNG) of the NEA-Frascati Research Centre. Twelve material samples were considered, namely: Mo, Cu, Hf, Mg, Ni, Cd, Sn, Re, Ti, W, Ag and Al. The ratios between calculated and experimental values (C/E) are shown and discussed in this paper.

[Assessment of modern radioecological situation at nuclear explosion "Chagan" (Balapan Site, Semipalatinsk Nuclear Test Site, Kazakhstan)].

PubMed

Evseeva, T I; Maĭstrenko, T A; Geras'kin, S A; Belykh, E S; Umarov, M A; Sergeeva, I Iu; Sergeev, V Iu

2008-01-01

Results on estimation of modern radioecological situation at nuclear explosion "Chagan" based on large-scale cartographic studies (1:25000) of a test area (4 km2) are presented. Maximum gamma-irradiation doses were observed at bulk of ground surrounded a crater and at radioactive fall-outs extended to the North-East and to the SouthWest from the crater. Based on data on artificial radionuclide specific activity most part of soil samples were attributed to radioactive wastes according to IAEA (1996) and OSPORB (1999). Natural decrease of soil radioactivity up to safety level due to 60Co, 137Cs, 90Sr, 152Eu, 154Eu radioactive decay and 241Am accumulation-decay will not take place within the next 60 years at the studied area.

α decay and cluster radioactivity of nuclei of interest to the synthesis of Z =119 , 120 isotopes

NASA Astrophysics Data System (ADS)

Poenaru, D. N.; Gherghescu, R. A.

2018-04-01

Super-heavy nuclei of interest for the forthcoming synthesis of the isotopes with Z =119 , 120 are investigated. One of the very interesting latest experiments was performed at the velocity filter SHIP (GSI Darmstadt) trying to produce 299120 in a fusion reaction 248Cm(54Cr,3 n )299120 . We report calculations of α -decay half-lives using four models: AKRA (Akrawy), ASAF (analytical superasymmetric fission), UNIV (universal formula), and semFIS (semi-empirical formula based on fission theory). The released energy, Q , is calculated using the theoretical model of atomic masses, WS4. For Sr,9492 cluster radioactivity of 120,302300 we predict a branching ratio relative to α decay of -0.10 and 0.49, respectively, meaning that it is worth trying to detect such kinds of decay modes in competition with α decay.

KSC-97PC1537

NASA Image and Video Library

1997-10-10

At Launch Complex 40 on Cape Canaveral Air Station, workers are installing three Radioisotope Thermoelectric Generators (RTGs) on the Cassini spacecraft. RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on 23 previous U.S. missions over the past 37 years. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 dioxide, a non-weapons-grade material. RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13

KSC-97PC1535

NASA Image and Video Library

1997-10-10

At Launch Complex 40 on Cape Canaveral Air Station, workers are installing three Radioisotope Thermoelectric Generators (RTGs) on the Cassini spacecraft. RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on 23 previous U.S. missions over the past 37 years. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 dioxide, a non-weapons-grade material. RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13

KSC-97PC1533

NASA Image and Video Library

1997-10-10

At Launch Complex 40 on Cape Canaveral Air Station, workers are installing three Radioisotope Thermoelectric Generators (RTGs) on the Cassini spacecraft. RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on 23 previous U.S. missions over the past 37 years. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 dioxide, a non-weapons-grade material. RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13

KSC-97PC1538

NASA Image and Video Library

1997-10-10

At Launch Complex 40 on Cape Canaveral Air Station, workers are installing three Radioisotope Thermoelectric Generators (RTGs) on the Cassini spacecraft. RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on 23 previous U.S. missions over the past 37 years. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 dioxide, a non-weapons-grade material. RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13

Hydrogen Production in Radioactive Solutions in the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

CRAWFORD, CHARLES L.

2004-05-26

In the radioactive slurries and solutions to be processed in the Defense Waste Processing Facility (DWPF), hydrogen will be produced continuously by radiolysis. This production results from alpha, beta, and gamma rays from decay of radionuclides in the slurries and solutions interacting with the water. More than 1000 research reports have published data concerning this radiolytic production. The results of these studies have been reviewed in a comprehensive monograph. Information about radiolytic hydrogen production from the different process tanks is necessary to determine air purge rates necessary to prevent flammable mixtures from accumulating in the vapor spaces above these tanks.more » Radiolytic hydrogen production rates are usually presented in terms of G values or molecules of hydrogen produced per 100ev of radioactive decay energy absorbed by the slurry or solution. With the G value for hydrogen production, G(H2), for a particular slurry and the concentrations of radioactive species in that slurry, the rate of H2 production for that slurry can be calculated. An earlier investigation estimated that the maximum rate that hydrogen could be produced from the sludge slurry stream to the DWPF is with a G value of 0.45 molecules per 100ev of radioactive decay energy sorbed by the slurry.« less

Light Curves of Hydrogen-poor Superluminous Supernovae from the Palomar Transient Factory

NASA Astrophysics Data System (ADS)

De Cia, Annalisa; Gal-Yam, A.; Rubin, A.; Leloudas, G.; Vreeswijk, P.; Perley, D. A.; Quimby, R.; Yan, Lin; Sullivan, M.; Flörs, A.; Sollerman, J.; Bersier, D.; Cenko, S. B.; Gal-Yam, M.; Maguire, K.; Ofek, E. O.; Prentice, S.; Schulze, S.; Spyromilio, J.; Valenti, S.; Arcavi, I.; Corsi, A.; Howell, D. A.; Mazzali, P.; Kasliwal, M. M.; Taddia, F.; Yaron, O.

2018-06-01

We investigate the light-curve properties of a sample of 26 spectroscopically confirmed hydrogen-poor superluminous supernovae (SLSNe-I) in the Palomar Transient Factory survey. These events are brighter than SNe Ib/c and SNe Ic-BL, on average, by about 4 and 2 mag, respectively. The peak absolute magnitudes of SLSNe-I in rest-frame g band span ‑22 ≲ M g ≲ ‑20 mag, and these peaks are not powered by radioactive 56Ni, unless strong asymmetries are at play. The rise timescales are longer for SLSNe than for normal SNe Ib/c, by roughly 10 days, for events with similar decay times. Thus, SLSNe-I can be considered as a separate population based on photometric properties. After peak, SLSNe-I decay with a wide range of slopes, with no obvious gap between rapidly declining and slowly declining events. The latter events show more irregularities (bumps) in the light curves at all times. At late times, the SLSN-I light curves slow down and cluster around the 56Co radioactive decay rate. Powering the late-time light curves with radioactive decay would require between 1 and 10 M ⊙ of Ni masses. Alternatively, a simple magnetar model can reasonably fit the majority of SLSNe-I light curves, with four exceptions, and can mimic the radioactive decay of 56Co, up to ∼400 days from explosion. The resulting spin values do not correlate with the host-galaxy metallicities. Finally, the analysis of our sample cannot strengthen the case for using SLSNe-I for cosmology.

Radioactivity Calculations

ERIC Educational Resources Information Center

Onega, Ronald J.

1969-01-01

Three problems in radioactive buildup and decay are presented and solved. Matrix algebra is used to solve the second problem. The third problem deals with flux depression and is solved by the use of differential equations. (LC)

An Excel[TM] Model of a Radioactive Series

ERIC Educational Resources Information Center

Andrews, D. G. H.

2009-01-01

A computer model of the decay of a radioactive series, written in Visual Basic in Excel[TM], is presented. The model is based on the random selection of cells in an array. The results compare well with the theoretical equations. The model is a useful tool in teaching this aspect of radioactivity. (Contains 4 figures.)

Limitations of Poisson statistics in describing radioactive decay.

PubMed

Sitek, Arkadiusz; Celler, Anna M

2015-12-01

The assumption that nuclear decays are governed by Poisson statistics is an approximation. This approximation becomes unjustified when data acquisition times longer than or even comparable with the half-lives of the radioisotope in the sample are considered. In this work, the limits of the Poisson-statistics approximation are investigated. The formalism for the statistics of radioactive decay based on binomial distribution is derived. The theoretical factor describing the deviation of variance of the number of decays predicated by the Poisson distribution from the true variance is defined and investigated for several commonly used radiotracers such as (18)F, (15)O, (82)Rb, (13)N, (99m)Tc, (123)I, and (201)Tl. The variance of the number of decays estimated using the Poisson distribution is significantly different than the true variance for a 5-minute observation time of (11)C, (15)O, (13)N, and (82)Rb. Durations of nuclear medicine studies often are relatively long; they may be even a few times longer than the half-lives of some short-lived radiotracers. Our study shows that in such situations the Poisson statistics is unsuitable and should not be applied to describe the statistics of the number of decays in radioactive samples. However, the above statement does not directly apply to counting statistics at the level of event detection. Low sensitivities of detectors which are used in imaging studies make the Poisson approximation near perfect. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bronskill, M.J.

The spatial distribution of radioactivity in the injection site, and its rate of clearance, have been measured in patients undergoing various types of interstitial radiocolloid lymphoscintigraphy using 99mTc-antimony sulfide colloid. The clearance of radioactivity from the injection site, and the expansion with time of the localized radioactivity vary considerably for different sites of injection. Maximum absorbed dose estimates of 45.6 rads to the center of the injection site (rectus sheath) and 21 rads to individual lymph nodes have been calculated for patients undergoing internal mammary lymphoscintigraphy with 450 mu Ci injected radioactivity. Absorbed dose estimates for finger web, toe web,more » and perianal injection sites are also presented.« less

Evaluation of IAEA Clearance Concept for Low-level Radioactive Waste from a Radioisotope Research Institute.

PubMed

Yumoto, Yasuhiro; Okada, Shigeru; Kinno, Ikuo; Nagamatsu, Tomohiro; Nouso, Kazuhiro; Nakayama, Eiichi

2016-05-01

The clearance of solid low-level radioactive laboratory waste (LLRW) after decay-in-storage (DIS) obtained from a research institute and thoroughly separated using the separation and classification protocols presented in this study was evaluated. The radioisotope (RI) content of incinerated LLRW from the specified RI research group (group A); the RI content of LLRW obtained in fiscal year 2000, which contained radionuclides with half-lives of less than 164 d (LLRW2); and the RI content of the LLRW reported in group A's disposal records were compared. The LLRW2 and LLRW of group A were incinerated after 2 y of decay-in-storage and immediately after storage, respectively. The highest ratio of the RI of incinerated LLRW to the value in the disposal records was 2.52 for ⁵¹Cr. The radioactivities of radionuclides in both the LLRW2 and LLRW for ³⁵S, ⁴⁵Ca, ⁵¹Cr, ¹²⁵I, ³²P, ³³P, and ⁹⁹mTc and the incinerated ash after 1 y later of decay-in-storage were below the clearance level defined by the RS-G-1.7 of the International Basic Safety Standard without contamination by ³H and ¹⁴C. These remains contained very small amounts of some long-half-life radionuclides of natural origin after 7 y of decay-in-storage. This LLRW separation protocol was effective for the separation of ³H and ¹⁴C. LLRW2 after 2 years of DIS and its incinerated ash after one year later of DIS were below the clearance level for radioactivity and radioactivity concentration.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nutter, J.D.; O`Hara, F.A.; Rodenburg, W.W.

A calorimeter is a device to measure evolved or adsorbed heat. For our purposes, the heat measured is that associated with radioactive decay and the unit of measurement is the watt. Each time an atom decays, energy is released and absorbed by the surroundings and heat generated. For each isotope, this heat is a constant related to the energy of the decay particles and the half-life of the isotope. A point which is often overlooked is that calorimetry is one of the oldest techniques known for measuring radioactivity. In 1903, Pierre Curie and A. Laborde used a twin microcalorimeter tomore » determine that one gram of radium generates about 100 calories per hour. Several months later, Curie and Dewar used liquid oxygen and hydrogen to show that the amount of energy developed by radium and other radioactive elements did not depend on temperature. At that time, this observation was extremely important. It indicated that the nature of radioactivity is entirely different and cannot be compared with any known phenomena. In all other thermal processes known in physics and chemistry, the rate at which heat is developed changes with temperature. In 1942, Monsanto was asked by General Leslie Groves, Head of the Manhattan Project, to accept the responsibility for the chemistry and metallurgy of radioactive polonium. Late in 1943, two Monsanto scientists began a study of the half-life of polonium-210 using calorimetry.« less

Measurement of Radon in Indoor Air.

ERIC Educational Resources Information Center

Downey, Daniel M.; Simolunas, Glenn

1988-01-01

Describes a laboratory experiment to teach the principles of air sampling, gamma ray spectroscopy, nuclear decay, and radioactive equilibrium. Analyzes radon by carbon adsorption and gamma ray counting. Provides methodology and rate of decay equations. (MVL)

10 CFR 35.92 - Decay-in-storage.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Decay-in-storage. 35.92 Section 35.92 Energy NUCLEAR...-storage. (a) A licensee may hold byproduct material with a physical half-life of less than or equal to 120 days for decay-in-storage before disposal without regard to its radioactivity if it— (1) Monitors...

10 CFR 35.92 - Decay-in-storage.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Decay-in-storage. 35.92 Section 35.92 Energy NUCLEAR...-storage. (a) A licensee may hold byproduct material with a physical half-life of less than or equal to 120 days for decay-in-storage before disposal without regard to its radioactivity if it— (1) Monitors...

When do star clusters become multiple star systems? II. Toward a half-life formalism with four bodies

NASA Astrophysics Data System (ADS)

Ibragimov, Timur; Leigh, Nathan W. C.; Ryu, Taeho; Panurach, Teresa; Perna, Rosalba

2018-03-01

We present a half-life formalism for describing the disruption of gravitationally-bound few-body systems, with a focus on binary-binary scattering. For negative total encounter energies, the four-body problem has three possible decay products in the point particle limit. For each decay product and a given set of initial conditions, we obtain directly from numerical scattering simulations the half-life for the distribution of disruption times. As in radioactive decay, the half-lives should provide a direct prediction for the relative fractions of each decay product. We test this prediction with simulated data and find good agreement with our hypothesis. We briefly discuss applications of this feature of the gravitational four-body problem to populations of black holes in globular clusters. This paper, the second in the series, builds on extending the remarkable similarity between gravitational chaos at the macroscopic scale and radioactive decay at the microscopic scale to larger-N systems.

When do star clusters become multiple star systems? II. Towards a half-life formalism with four bodies

NASA Astrophysics Data System (ADS)

Ibragimov, Timur; Leigh, Nathan W. C.; Ryu, Taeho; Panurach, Teresa; Perna, Rosalba

2018-07-01

We present a half-life formalism for describing the disruption of gravitationally bound few-body systems, with a focus on binary-binary scattering. For negative total encounter energies, the four-body problem has three possible decay products in the point-particle limit. For each decay product and a given set of initial conditions, we obtain directly from numerical scattering simulations the half-life for the distribution of disruption times. As in radioactive decay, the half-lives should provide a direct prediction for the relative fractions of each decay product. We test this prediction with simulated data and find good agreement with our hypothesis. We briefly discuss applications of this feature of the gravitational four-body problem to populations of black holes in globular clusters. This paper, the second in the series, builds on extending the remarkable similarity between gravitational chaos at the macroscopic scale and radioactive decay at the microscopic scale to larger-N systems.

EFFICIENCY OF THE FILTERS AGAINST RADIOACTIVE AEROSOL. ON THE RADIOACTIVE CONTAMINATION AND ITS REMOVAL (in Japanese)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miura, T.; Kimura, K.

1959-12-01

Dust filters were examined using a radioactive solidaerosol, decay product daughters of Rn/sup 220/. An examination with a thermal precipitator revealed that the major part of particles in the radioactive aerosol were smaller than 0.5 mu in diameter. Twenty-one kinds of filters were tested. The filtering efficiency was highest in asbestos fiber filters. A radioautographic examination revealed that the radioactive substance penetrated as deep as 1.4 to 1.5 mm into the filter layer. (auth)

Simulation of decay processes and radiation transport times in radioactivity measurements

NASA Astrophysics Data System (ADS)

García-Toraño, E.; Peyres, V.; Bé, M.-M.; Dulieu, C.; Lépy, M.-C.; Salvat, F.

2017-04-01

The Fortran subroutine package PENNUC, which simulates random decay pathways of radioactive nuclides, is described. The decay scheme of the active nuclide is obtained from the NUCLEIDE database, whose web application has been complemented with the option of exporting nuclear decay data (possible nuclear transitions, branching ratios, type and energy of emitted particles) in a format that is readable by the simulation subroutines. In the case of beta emitters, the initial energy of the electron or positron is sampled from the theoretical Fermi spectrum. De-excitation of the atomic electron cloud following electron capture and internal conversion is described using transition probabilities from the LLNL Evaluated Atomic Data Library and empirical or calculated energies of released X rays and Auger electrons. The time evolution of radiation showers is determined by considering the lifetimes of nuclear and atomic levels, as well as radiation propagation times. Although PENNUC is designed to operate independently, here it is used in conjunction with the electron-photon transport code PENELOPE, and both together allow the simulation of experiments with radioactive sources in complex material structures consisting of homogeneous bodies limited by quadric surfaces. The reliability of these simulation tools is demonstrated through comparisons of simulated and measured energy spectra from radionuclides with complex multi-gamma spectra, nuclides with metastable levels in their decay pathways, nuclides with two daughters, and beta plus emitters.

Radionuclides: Accumulation and Transport in Plants.

PubMed

Gupta, D K; Chatterjee, S; Datta, S; Voronina, A V; Walther, C

Application of radioactive elements or radionuclides for anthropogenic use is a widespread phenomenon nowadays. Radionuclides undergo radioactive decays releasing ionizing radiation like gamma ray(s) and/or alpha or beta particles that can displace electrons in the living matter (like in DNA) and disturb its function. Radionuclides are highly hazardous pollutants of considerable impact on the environment, food chain and human health. Cleaning up of the contaminated environment through plants is a promising technology where the rhizosphere may play an important role. Plants belonging to the families of Brassicaceae, Papilionaceae, Caryophyllaceae, Poaceae, and Asteraceae are most important in this respect and offer the largest potential for heavy metal phytoremediation. Plants like Lactuca sativa L., Silybum marianum Gaertn., Centaurea cyanus L., Carthamus tinctorius L., Helianthus annuus and H. tuberosus are also important plants for heavy metal phytoremediation. However, transfer factors (TF) of radionuclide from soil/water to plant ([Radionuclide]plant/[Radionuclide]soil) vary widely in different plants. Rhizosphere, rhizobacteria and varied metal transporters like NRAMP, ZIP families CDF, ATPases (HMAs) family like P1B-ATPases, are involved in the radio-phytoremediation processes. This review will discuss recent advancements and potential application of plants for radionuclide removal from the environment.

On the claim of modulations in radon decay and their association with solar rotation

NASA Astrophysics Data System (ADS)

Pommé, S.; Lutter, G.; Marouli, M.; Kossert, K.; Nähle, O.

2018-01-01

Claims were made by Sturrock et al. that radioactive decay can be induced by interaction of the nucleus with solar neutrinos and that cyclic modulations in decay rates are indicative of the dynamics of the solar interior. They analysed a series of measurements of gamma radiation associated with the emanation and decay of radon in a sealed container at the Geological Survey of Israel (GSI) laboratory. The integral count rates in the NaI detector showed strong variations in time of year and time of day. From time-series analysis, Sturrock et al. claim the presence of small oscillations at frequencies in a range between 7.4 a-1 and 12.5 a-1, which they speculatively associated with rotational influence on the solar neutrino flux. In this work, it is argued that the GSI radon measurements are unsuited for studying the variability of decay constants, because the data are strongly influenced by environmental conditions, such as solar irradiance and rainfall. At the JRC and PTB, decay rate measurements of the radon decay chain were performed with ionisation chambers, gamma-ray spectrometers and an alpha spectrometer. No deviation from the exponential-decay law was observed. The existence of cyclic variations in the decay constants is refuted, as well as the concept of measuring solar rotation through radioactive decay.

KSC-97PC1534

NASA Image and Video Library

1997-10-10

At Launch Complex 40 on Cape Canaveral Air Station, one of three Radioisotope Thermoelectric Generators (RTGs) is being installed on the Cassini spacecraft. RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on 23 previous U.S. missions over the past 37 years. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 dioxide, a non-weapons-grade material. RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13

KSC-97PC1532

NASA Image and Video Library

1997-10-10

KENNEDY SPACE CENTER, FLA. -- At Launch Complex 40 on Cape Canaveral Air Station, workers are installing three Radioisotope Thermoelectric Generators (RTGs) on the Cassini spacecraft. RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on 23 previous U.S. missions over the past 37 years. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 dioxide, a non-weapons-grade material. RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13

KSC-97PC1536

NASA Image and Video Library

1997-10-10

KENNEDY SPACE CENTER, FLA. -- At Launch Complex 40 on Cape Canaveral Air Station, workers are installing three Radioisotope Thermoelectric Generators (RTGs) on the Cassini spacecraft. RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on 23 previous U.S. missions over the past 37 years. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 dioxide, a non-weapons-grade material. RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13

Workers install the RTGs on the Cassini spacecraft at LC 40, CCAS

NASA Technical Reports Server (NTRS)

1997-01-01

At Launch Complex 40 on Cape Canaveral Air Station, workers are installing three Radioisotope Thermoelectric Generators (RTGs) on the Cassini spacecraft. RTGs are lightweight, compact spacecraft electrical power systems that have flown successfully on 23 previous U.S. missions over the past 37 years. These generators produce power by converting heat into electrical energy; the heat is provided by the natural radioactive decay of plutonium-238 dioxide, a non-weapons-grade material. RTGs enable spacecraft to operate at significant distances from the Sun where solar power systems would not be feasible. Cassini will travel two billion miles to reach Saturn and another 1.1 billion miles while in orbit around Saturn. Cassini is undergoing final preparations for liftoff on a Titan IVB/Centaur launch vehicle, with the launch window opening at 4:55 a.m. EDT, Oct. 13.

Assessing the Effectiveness of Risk Communication for Maintenance Workers Who Deal With Induced Radioactivity Management of Medical Linear Accelerators.

PubMed

Watanabe, Hiroshi; Maehara, Yoshiaki; Fujibuchi, Toshioh; Koizumi, Mitsue; Yamaguchi, Ichiro; Kida, Tetsuo; Ooyama, Masaya; Horitsugi, Genki; Hiraki, Hitoshi; Tsukamoto, Atsuko; Itami, Jyun

2015-08-01

In Japan, an amended law that mandates levels of unintended induced radioactivity has been in effect since 1 April 2012. According to the new regulation, if the concentration of induced radioactivity in affected parts is above the clearance level, the parts must be regarded as radioactive even if they weigh less than 1 kg. This regulation reform raises several new issues concerning medical linear accelerators, including how to determine the decay period for induced radioactivity before maintenance can be performed and how to identify what parts should be considered radioactive waste. The authors performed several risk communication (RC) activities aimed at improving the understanding of maintenance workers at medical accelerator manufacturers and establishing good guidelines by involving stakeholders. For this purpose, a working group was established and conducted RC activities, such as holding opinion exchange meetings between medical staff and maintenance workers and creating a booklet to answer questions from maintenance workers. To evaluate these activities, three questionnaire surveys were conducted between 2011 and 2014. According to the results of this study, the ratio of maintenance workers who accepted "The decay period is within one week" was approximately 60% at the third survey and significantly increased (P < 0.0001) during the survey period. Approximately 25% of the maintenance workers felt that not enough information was provided about the decay period, and approximately 63% thought that the information provided on the health effects of radiation was sufficient. These results suggest that the present RC was successful.

Measurement of the total activity concentrations of Libyan oil scale

NASA Astrophysics Data System (ADS)

Da Silva, F. C. A.; Bradley, D. A.; Regan, P. H.; Rozaila, Z. Siti

2017-08-01

Twenty-three oil scale samples obtained from the Libyan oil and gas industry production facilities onshore have been measured using high-resolution gamma-ray spectrometry with a shielded HPGe detector, the work being carried out within the Environmental Radioactivity Laboratory at the University of Surrey. The main objectives of this work were to determine the extent to which the predominant radionuclides associated with the uranium and thorium natural decay chains were in secular equilibrium with their decay progeny, also to compare differences between the total activity concentrations (TAC) in secular equilibrium and disequilibrium and to evaluate the measured activities for the predominant gamma-ray emitting decay radionuclides within the 232Th and 238U chains. The oil scale NORM samples did not exhibit radioactive equilibrium between the decay progeny and longer-lived parent radionuclides of the 238U and 232Th series.

Experimental data on ground- and excited-state properties for all nuclei with mass number A=144 have been compiled and evaluated. States populated in radioactive decay as well as in nuclear reactions have been considered. For these nuclei, level and decay schemes have been built, as well as tables of nuclear properties. This work supersedes the 1989 evaluation by J.K. Tuli (1989Tu02). Manuscripts published before December 2000 have been included in this work

NASA Astrophysics Data System (ADS)

Sonzogni, A. A.

2001-07-01

Experimental data on ground- and excited-state properties for all nuclei with mass number A = 144 have been compiled and evaluated. States populated in radioactive decay as well as in nuclear reactions have been considered. For these nuclei, level and decay schemes have been built, as well as tables of nuclear properties. This work supersedes the 1989 evaluation by J.K. Tuli (1989Tu02). Manuscripts published before December 2000 have been included in this work.

Nuclear spectroscopy with Geant4: Proton and neutron emission & radioactivity

NASA Astrophysics Data System (ADS)

Sarmiento, L. G.; Rudolph, D.

2016-07-01

With the aid of a novel combination of existing equipment - JYFLTRAP and the TASISpec decay station - it is possible to perform very clean quantum-state selective, high-resolution particle-γ decay spectroscopy. We intend to study the determination of the branching ratio of the ℓ = 9 proton emission from the Iπ = 19/2-, 3174-keV isomer in the N = Z - 1 nucleus 53Co. The study aims to initiate a series of similar experiments along the proton dripline, thereby providing unique insights into "open quantum systems". The technique has been pioneered in case studies using SHIPTRAP and TASISpec at GSI. Newly available radioactive decay modes in Geant4 simulations are going to corroborate the anticipated experimental results.

Anomalous effects of radioactive decay rates and capacitance values measured inside a modified Faraday cage: Correlations with space weather

NASA Astrophysics Data System (ADS)

Scholkmann, F.; Milián-Sánchez, V.; Mocholí-Salcedo, A.; Milián, C.; Kolombet, V. A.; Verdú, G.

2017-03-01

Recently we reported (Milián-Sánchez V. et al., Nucl. Instrum. Methods A, 828 (2016) 210) our experimental results involving 226Ra decay rate and capacitance measurements inside a modified Faraday cage. Our measurements exhibited anomalous effects of unknown origin. In this letter we report new results regarding our investigation into the origins of the observed effects. We report preliminary findings of a correlation analysis between the radioactive decay rates and capacitance time series and space weather related variables (geomagnetic field disturbances and cosmic-ray neutron counts). A significant correlation was observed for specific data sets. The results are presented and possible implications for future work discussed.

Identify source location and release time for pollutants undergoing super-diffusion and decay: Parameter analysis and model evaluation

NASA Astrophysics Data System (ADS)

Zhang, Yong; Sun, HongGuang; Lu, Bingqing; Garrard, Rhiannon; Neupauer, Roseanna M.

2017-09-01

Backward models have been applied for four decades by hydrologists to identify the source of pollutants undergoing Fickian diffusion, while analytical tools are not available for source identification of super-diffusive pollutants undergoing decay. This technical note evaluates analytical solutions for the source location and release time of a decaying contaminant undergoing super-diffusion using backward probability density functions (PDFs), where the forward model is the space fractional advection-dispersion equation with decay. Revisit of the well-known MADE-2 tracer test using parameter analysis shows that the peak backward location PDF can predict the tritium source location, while the peak backward travel time PDF underestimates the tracer release time due to the early arrival of tracer particles at the detection well in the maximally skewed, super-diffusive transport. In addition, the first-order decay adds additional skewness toward earlier arrival times in backward travel time PDFs, resulting in a younger release time, although this impact is minimized at the MADE-2 site due to tritium's half-life being relatively longer than the monitoring period. The main conclusion is that, while non-trivial backward techniques are required to identify pollutant source location, the pollutant release time can and should be directly estimated given the speed of the peak resident concentration for super-diffusive pollutants with or without decay.

Cement As a Waste Form for Nuclear Fission Products: The Case of (90)Sr and Its Daughters.

PubMed

Dezerald, Lucile; Kohanoff, Jorge J; Correa, Alfredo A; Caro, Alfredo; Pellenq, Roland J-M; Ulm, Franz J; Saúl, Andrés

2015-11-17

One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of (90)Sr insertion and decay in C-S-H (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold this radioactive fission product and to investigate the consequences of its β-decay on the cement paste structure. We show that (90)Sr is stable when it substitutes the Ca(2+) ions in C-S-H, and so is its daughter nucleus (90)Y after β-decay. Interestingly, (90)Zr, daughter of (90)Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Therefore, cement appears as a suitable waste form for (90)Sr storage.

Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger

NASA Astrophysics Data System (ADS)

Arcavi, Iair; Hosseinzadeh, Griffin; Howell, D. Andrew; McCully, Curtis; Poznanski, Dovi; Kasen, Daniel; Barnes, Jennifer; Zaltzman, Michael; Vasylyev, Sergiy; Maoz, Dan; Valenti, Stefano

2017-11-01

The merger of two neutron stars has been predicted to produce an optical-infrared transient (lasting a few days) known as a ‘kilonova’, powered by the radioactive decay of neutron-rich species synthesized in the merger. Evidence that short γ-ray bursts also arise from neutron-star mergers has been accumulating. In models of such mergers, a small amount of mass (10-4-10-2 solar masses) with a low electron fraction is ejected at high velocities (0.1-0.3 times light speed) or carried out by winds from an accretion disk formed around the newly merged object. This mass is expected to undergo rapid neutron capture (r-process) nucleosynthesis, leading to the formation of radioactive elements that release energy as they decay, powering an electromagnetic transient. A large uncertainty in the composition of the newly synthesized material leads to various expected colours, durations and luminosities for such transients. Observational evidence for kilonovae has so far been inconclusive because it was based on cases of moderate excess emission detected in the afterglows of γ-ray bursts. Here we report optical to near-infrared observations of a transient coincident with the detection of the gravitational-wave signature of a binary neutron-star merger and with a low-luminosity short-duration γ-ray burst. Our observations, taken roughly every eight hours over a few days following the gravitational-wave trigger, reveal an initial blue excess, with fast optical fading and reddening. Using numerical models, we conclude that our data are broadly consistent with a light curve powered by a few hundredths of a solar mass of low-opacity material corresponding to lanthanide-poor (a fraction of 10-4.5 by mass) ejecta.

Using Melting Ice to Teach Radiometric Dating.

ERIC Educational Resources Information Center

Wise, Donald Underkofler

1990-01-01

Presented is an activity in which a mystery setting is used to motivate students to construct their own decay curves of melting ice used as an analogy to radioactive decay. Procedures, materials, apparatus, discussion topics, presentation, and thermodynamics are discussed. (CW)

Doubling Time for Nonexponential Families of Functions

ERIC Educational Resources Information Center

Gordon, Sheldon P.

2010-01-01

One special characteristic of any exponential growth or decay function f(t) = Ab[superscript t] is its unique doubling time or half-life, each of which depends only on the base "b". The half-life is used to characterize the rate of decay of any radioactive substance or the rate at which the level of a medication in the bloodstream decays as it is…

Dissolution and clearance of titanium tritide particles in the lungs of F344/Crl rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Yung-Sung; Snipes, M.B.; Wang, Yansheng

1995-12-01

Metal tritides are compounds in which the radioactive isotope tritium, following adsorption onto the metal, forms a stable chemical compound with the metal. When particles of tritiated metals become airborne, they can be inhaled by workers. Because the particles may be retained in the lung for extended periods, the resulting dose will be greater than doses following exposure to tritium gas or tritium oxide (HTO). Particles of triated metals may be dispersed into the air during routine handling, disruption of contaminated metals, or as a result of spontaneous radioactive decay processes. Unlike metal hydrides and deuterides, tritides are radioactive, andmore » the decay of the tritium atoms affects the metal. Because helium is a product of the decay, helium bubbles form within the metal tritide matrix. The pressure from these bubbles leads to respirable particles breaking off from the tritide surface. Our results show that a substantial amount of titanium tritide remains in the rat lung 10 d after intratracheal instillation, confirming results previously obtain in an in vitro dissolution study.« less

Liquid xenon purification, de-radonation (and de-kryptonation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pocar, Andrea, E-mail: pocar@umass.edu; Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550

Liquid xenon detectors are at the forefront of rare event physics, including searches for neutrino-less double beta decay and WIMP dark matter. The xenon for these experiments needs to be purified from chemical impurities such as electronegative atoms and molecules, which absorb ionization electrons, and VUV (178 nm) scintillation light-absorbing chemical species. In addition, superb purification from radioactive impurities is required. Particularly challenging are radioactive noble isotopes ({sup 85}Kr,{sup 39,42}Ar,{sup 220,222}Rn). Radon is a particularly universal problem, due to the extended decay sequence of its daughters and its ubiquitous presence in detector materials. Purification and de-radonation of liquid xenon aremore » addressed with particular focus on the experience gained with the EXO-200 neutrino-less double beta decay detector.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aguilar-Arevalo, A.

We present measurements of radioactive contamination in the high-resistivity silicon charge-coupled devices (CCDs) used by the DAMIC experiment to search for dark matter particles. Novel analysis methods, which exploit the unique spatial resolution of CCDs, were developed to identify α and β particles. Uranium and thorium contamination in the CCD bulk was measured through α spectroscopy, with an upper limit on the 238U ( 232Th) decay rate of 5 (15) kg -1 d -1 at 95% CL. We also searched for pairs of spatially correlated electron tracks separated in time by up to tens of days, as expected from 32Simore » – 32P or 210Pb – 210Bi sequences of b decays. The decay rate of 32Si was found to be 80 +110 -65 (95% CI). An upper limit of ~35 kg -1 d -1 (95% CL) on the 210Pb decay rate was obtained independently by α spectroscopy and the β decay sequence search. Furthermore, these levels of radioactive contamination are sufficiently low for the successful operation of CCDs in the forthcoming 100 g DAMIC detector.« less

Dependence of two-proton radioactivity on nuclear pairing models

NASA Astrophysics Data System (ADS)

Oishi, Tomohiro; Kortelainen, Markus; Pastore, Alessandro

2017-10-01

Sensitivity of two-proton emitting decay to nuclear pairing correlation is discussed within a time-dependent three-body model. We focus on the 6Be nucleus assuming α +p +p configuration, and its decay process is described as a time evolution of the three-body resonance state. For a proton-proton subsystem, a schematic density-dependent contact (SDDC) pairing model is employed. From the time-dependent calculation, we observed the exponential decay rule of a two-proton emission. It is shown that the density dependence does not play a major role in determining the decay width, which can be controlled only by the asymptotic strength of the pairing interaction. This asymptotic pairing sensitivity can be understood in terms of the dynamics of the wave function driven by the three-body Hamiltonian, by monitoring the time-dependent density distribution. With this simple SDDC pairing model, there remains an impossible trinity problem: it cannot simultaneously reproduce the empirical Q value, decay width, and the nucleon-nucleon scattering length. This problem suggests that a further sophistication of the theoretical pairing model is necessary, utilizing the two-proton radioactivity data as the reference quantities.

Radiometric Dating in Geology.

ERIC Educational Resources Information Center

Pankhurst, R. J.

1980-01-01

Described are several aspects and methods of quantitatively measuring geologic time using a constant-rate natural process of radioactive decay. Topics include half lives and decay constants, radiogenic growth, potassium-argon dating, rubidium-strontium dating, and the role of geochronology in support of geological exploration. (DS)

Precision Gamma-Ray Branching Ratios for Long-Lived Radioactive Nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tonchev, Anton

Many properties of the high-energy-density environments in nuclear weapons tests, advanced laser-fusion experiments, the interior of stars, and other astrophysical bodies must be inferred from the resulting long-lived radioactive nuclei that are produced. These radioactive nuclei are most easily and sensitively identified by studying the characteristic gamma rays emitted during decay. Measuring a number of decays via detection of the characteristic gamma-rays emitted during the gamma-decay (the gamma-ray branching ratio) of the long-lived fission products is one of the most straightforward and reliable ways to determine the number of fissions that occurred in a nuclear weapon test. The fission productsmore » 147Nd, 144Ce, 156Eu, and certain other long-lived isotopes play a crucial role in science-based stockpile stewardship, however, the large uncertainties (about 8%) on the branching ratios measured for these isotopes are currently limiting the usefulness of the existing data [1,2]. We performed highly accurate gamma-ray branching-ratio measurements for a group of high-atomic-number rare earth isotopes to greatly improve the precision and reliability with which the fission yield and reaction products in high-energy-density environments can be determined. We have developed techniques that take advantage of new radioactive-beam facilities, such as DOE's CARIBU located at Argonne National Laboratory, to produce radioactive samples and perform decay spectroscopy measurements. The absolute gamma-ray branching ratios for 147Nd and 144Ce are reduced <2% precision. In addition, high-energy monoenergetic neutron beams from the FN Tandem accelerator in TUNL at Duke University was used to produce 167Tm using the 169Tm(n,3n) reaction. Fourtime improved branching ratio of 167Tm is used now to measure reaction-in-flight (RIF) neutrons from a burning DT capsule at NIF [10]. This represents the first measurement of RIF neutrons in any laboratory fusion system, and the magnitude of the signal has important implications for fundamental plasma science and for weapons physics.« less

Radiation Protection. Measurement of radioactivity in the environment - Air- radon 222. A proposed ISO standard.

NASA Astrophysics Data System (ADS)

Gillmore, G.; Woods, M.

2009-04-01

Radon isotopes (222, 220, 219) are radioactive gases produced by the disintegration of radium isotopes 226, 224 and 223, which are decay products of uranium238, thorium232 and uranium235 respectively. All are found in the earth's crust. Solid elements, also radioactive, are produced by radon disintegration. Radon is classed as a rare gas in the periodic table of elements, along with helium, argon, neon, krypton and xenon. When disintegrating, radon emits alpha particles and generates solid decay products, which are also radioactive (polonium, bismuth, lead etc.). The potential danger of radon lies in its solid decay products rather than the gas itself. Whether or not they are attached aerosols, radon decay products can be inhaled and deposited in the bronchopulmonary tree to varying depths according to their size. Radon today is considered to be the main source of human exposure to natural radiation. At the international level, radon accounts for 52% of global average exposure to natural radiation. Isotope 222 (48%) is far more significant than isotope 220 (4%), whilst isotope 219 is considered as negligible. Exposure to radon varies considerably from one region to another, depending on factors such as weather conditions, and underlying geology. Activity concentration can therefore vary by a factor of 10 or even a 100 from one period of time to the next and from one area to another. There are many ways of measuring the radon 222 activity concentration and the potential alpha energy concentration of its short-lived decay products. Measuring techniques fall into three categories: - spot measurement methods; continuous measurement; integrated measurement. The proposed ISO (International Organisation for Standardisation) document suggests guidelines for measuring radon222 activity concentration and the potential alpha energy concentration of its short-lived decay products in a free (environment) and confined (buildings) atmosphere. The target date for availability of this work item is 2011. The ISO document here highlighted is a working draft. ISO is a worldwide federation of national standards bodies. Keywords: radon; international standards; measurement techniques.

Evidence for Ni-56 yields Co-56 yields Fe-56 decay in type Ia supernovae

NASA Technical Reports Server (NTRS)

Kuchner, Marc J.; Kirshner, Robert P.; Pinto, Philip A.; Leibundgut, Bruno

1994-01-01

In the prevailing picture of Type Ia supernovae (SN Ia), their explosive burning produces Ni-56, and the radioactive decay chain Ni-56 yields Co-56 yields Fe-56 powers the subsequent emission. We test a central feature of this theory by measuring the relative strengths of a (Co III) emission feature near 5900 A and a (Fe III) emission feature near 4700 A. We measure 38 spectra from 13 SN Ia ranging from 48 to 310 days after maximum light. When we compare the observations with a simple multilevel calculation, we find that the observed Fe/Co flux ratio evolves as expected when the Fe-56/Co-56 abundance ratio follows from Ni-56 yields Co-56 yields Fe-56 decay. From this agreement, we conclude that the cobalt and iron atoms we observe through SN Ia emission lines are produced by the radioactive decay of Ni-56, just as predicted by a wide range of models for SN Ia explosions.

Clues in the rare gas isotopes to early solar system history

NASA Technical Reports Server (NTRS)

Reynolds, J. H.

1977-01-01

The results of the radioactive dating and the discovery of gas-rich meteorites on the Moon surface are reviewed. Special attention is paid to the extinct radioactivity iodine-129. This radioactivity is produced by r-process of nucleosynthesis and it decays with a half-life of 17 m.y. It provides a clock sensitive to small changes in the early years of the solar system.

BioChroma – A New and Patented Technology for Processing Radioactive Wastewater from Nuclear Medicine Therapy Facilities in Hospitals and Clinics

PubMed Central

Rodríguez, José Canga

2012-01-01

After undergoing radionuclide therapy, patients generate wastewater with a considerable amount of radioactivity, which can reach levels of as much as 90% of the administered dose. Due to the risk of accumulation after discharge into the sewer, it is advisable to collect this effluent for its treatment prior to final discharge. Delay and decay (natural decomposition of the isotope) is the most commonly used technical method of abating radioactive iodine, but it is frequently criticized as being complex and very expensive. BioChroma is a technology that has been developed as an alternative to these complicated and expensive systems. This paper describes this new technology and presents, as an example, a system that was installed and successfully commissioned in the middle of 2008 in a nuclear medicine ward with 12 beds in Stuttgart (Germany). Based on existing legislation, the responsible authorities and the company that operated the hospital agreed on a maximum activity level of 5 Bq/l. If a typical delay and decay system would have been installed, the 180 m3 treatment plant that was already available in the hospital cellar would have to be extended by additional 150 m3. By implementing the patented BioChroma process, the space requirements were reduced by 75%. For instance, since the new system was integrated into the existing installation, tanks accounting for 120 m³ could be used as buffering volume in the new wastewater treatment plant. The operation of the referred plant is currently producing very good results with values below the specified limit of 5 Bq/l for the isotope 131I. In addition, 90Y has been reported to be eliminated at the same time. Over the past 2 years of operation, the wastewater treatment plant has been able to achieve a maximum processing capacity of more than 2,000 l/day, which equates to a nuclear medicine ward with approx. 20 beds. The highest level recorded during the test period (of 180 days after start-up) was a peak of nearly 2,800 l/day. PMID:22942776

Superallowed Fermi β decay studies at TRIUMF-ISAC

NASA Astrophysics Data System (ADS)

Svensson, C. E.; Dunlop, R.; Finlay, P.; Ball, G. C.; Ettenauer, S.; Leslie, J. R.; Towner, I. S.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Demand, G.; Djongolov, M.; Garnsworthy, A. B.; Garrett, P. E.; Green, K. L.; Glister, J.; Grinyer, G. F.; Hackman, G.; Hadinia, B.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2013-10-01

A program of high-precision superallowed Fermi β decay studies is being carried out at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility at TRIUMF. Recent high-precision branching ratio measurements for the superallowed decays of 74Rb and 26Alm, as well as a half-life measurement for 26Alm that is the most precise half-life measurement for any superallowed emitter to date, are reported. These results provide demanding tests of the theoretical isospin symmetry breaking corrections in superallowed Fermi β decays.

Surface alpha backgrounds from plate-out of radon progeny

NASA Astrophysics Data System (ADS)

Perumpilly, Gopakumar; Guiseppe, Vincente

2012-03-01

Low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly Rn-222) and its subsequent daughters present in an experiment are potential backgrounds, more troublesome is the deposition of radon daughters on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by daughters supported by the long half life (22 y) of Pb-210 on sensitive locations of a detector. We have developed a model of the radon progeny implantation using Geant4 simulations based on the low energy nuclear recoil process. We explore the alpha decays from implanted progeny on a Ge crystal as potential backgrounds for a neutrinoless double-beta decay experiment. Results of the simulations validated with alpha spectrum measurement of plate-out samples will be presented.

Cement As a Waste Form for Nuclear Fission Products: The Case of 90Sr and Its Daughters [Cement As a Container for Nuclear Fission Products: The Case of 90Sr and Its Daughters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dezerald, Lucile; Kohanoff, Jorge J.; Correa, Alfredo A.

One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of 90Sr insertion and decay in C–S–H (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold thismore » radioactive fission product and to investigate the consequences of its β-decay on the cement paste structure. We show that 90Sr is stable when it substitutes the Ca 2+ ions in C–S–H, and so is its daughter nucleus 90Y after β-decay. Interestingly, 90Zr, daughter of 90Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Furthermore, cement appears as a suitable waste form for 90Sr storage.« less

Cement As a Waste Form for Nuclear Fission Products: The Case of 90Sr and Its Daughters [Cement As a Container for Nuclear Fission Products: The Case of 90Sr and Its Daughters

DOE PAGES

Dezerald, Lucile; Kohanoff, Jorge J.; Correa, Alfredo A.; ...

2015-10-29

One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of 90Sr insertion and decay in C–S–H (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold thismore » radioactive fission product and to investigate the consequences of its β-decay on the cement paste structure. We show that 90Sr is stable when it substitutes the Ca 2+ ions in C–S–H, and so is its daughter nucleus 90Y after β-decay. Interestingly, 90Zr, daughter of 90Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Furthermore, cement appears as a suitable waste form for 90Sr storage.« less

[Nationwide survey on radioactive waste management related to positron emission tomography in Japan].

PubMed

Nagaoka, Hiroaki; Watanabe, Hiroshi; Yamaguchi, Ichiro; Fujibuchi, Toshioh; Kida, Tetsuo; Tanaka, Shinji

2009-12-20

A clearance system for medical radioactive solid waste has not yet been implemented in Japan. Since 2004 new regulations have allowed institutions using positron emission tomography(PET)to handle totally decayed radioactive waste as non-radioactive waste after decay-in-storage. It was expected that this new regulation would mediate the installation of clearance systems in Japan. In order to assess the current situation of radiation safety management in PET institutions, we conducted a nationwide survey. The study design was a cross-sectional descriptive study conducted by questionnaire. The subjects of this survey were all the PET institutions in Japan. Among 224 institutes, 128 institutes are equipped with cyclotrons and 96 institutes are not. The number of returned questionnaires was 138. Among institutes that are using delivered radiopharmaceuticals, 80% treat their waste as non-radioactive according to the new regulation. The impact of new regulations for reducing radioactive waste in PET institutes without a cyclotron was estimated at about $400 thousand per year. The main concern of medical institutes was assessment of the contamination caused by by-products of radioactive nuclides generated in target water during the operation of a cyclotron. It was thought that a rational rule based on scientific risk management should be established because these by-products of radioactive nuclides are negligible for radiation safety. New regulation has had a good influence on medical PET institutes, and it is expected that a clearance system for medical radioactive waste will be introduced in the near future, following these recent experiences in PET institutes.

10 CFR 72.104 - Criteria for radioactive materials in effluents and direct radiation from an ISFSI or MRS.

Code of Federal Regulations, 2011 CFR

2011-01-01

... controlled area must not exceed 0.25 mSv (25 mrem) to the whole body, 0.75 mSv (75 mrem) to the thyroid and 0... radioactive materials, radon and its decay products excepted, to the general environment, (2) Direct radiation...

10 CFR 72.104 - Criteria for radioactive materials in effluents and direct radiation from an ISFSI or MRS.

Code of Federal Regulations, 2010 CFR

2010-01-01

... controlled area must not exceed 0.25 mSv (25 mrem) to the whole body, 0.75 mSv (75 mrem) to the thyroid and 0... radioactive materials, radon and its decay products excepted, to the general environment, (2) Direct radiation...

Radiotoxicity and decay heat power of spent nuclear fuel of VVER type reactors at long-term storage.

PubMed

Bergelson, B R; Gerasimov, A S; Tikhomirov, G V

2005-01-01

Radiotoxicity and decay heat power of the spent nuclear fuel of VVER-1000 type reactors are calculated during storage time up to 300,000 y. Decay heat power of radioactive waste (radwaste) determines parameters of the heat removal system for the safe storage of spent nuclear fuel. Radiotoxicity determines the radiological hazard of radwaste after its leakage and penetration into the environment.

Modeling Nuclear Decay: A Point of Integration between Chemistry and Mathematics.

ERIC Educational Resources Information Center

Crippen, Kent J.; Curtright, Robert D.

1998-01-01

Describes four activities that use graphing calculators to model nuclear-decay phenomena. Students ultimately develop a notion about the radioactive waste produced by nuclear fission. These activities are in line with national educational standards and allow for the integration of science and mathematics. Contains 13 references. (Author/WRM)

40 CFR 61.101 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... distribution in the body of reference man. The unit of the effective dose equivalent is the rem. For purposes of this subpart doses caused by radon-222 and its decay products formed after the radon is released... radioactive decay. [54 FR 51697, Dec. 15, 1989, as amended at 61 FR 68981, Dec. 30, 1996] ...

Production of 35S for a Liquid Semiconductor Betavoltaic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meier, David E.; Garnov, A. Y.; Robertson, J. D.

2009-10-01

The specific energy density from radioactive decay is five to six orders of magnitude greater than the specific energy density in conventional chemical battery and fuel cell technologies. We are currently investigating the use of liquid semiconductor based betavoltaics as a way to directly convert the energy of radioactive decay into electrical power and potentially avoid the radiation damage that occurs in solid state semiconductor devices due to non-ionizing energy loss. Sulfur-35 was selected as the isotope for the liquid semiconductor demonstrations because it can be produced in high specific activity and it is chemically compatible with known liquid semiconductormore » media.« less

Measurement of radioactive contamination in the CCD’s of the DAMIC experiment

NASA Astrophysics Data System (ADS)

Aguilar-Arevalo, A.; Amidei, D.; Bertou, X.; Bole, D.; Butner, M.; Cancelo, G.; Castañeda Vásquez, A.; Chavarria, A. E.; de Mello Neto, J. R. T.; Dixon, S.; D'Olivo, J. C.; Estrada, J.; Fernandez Moroni, G.; Hernández Torres, K. P.; Izraelevitch, F.; Kavner, A.; Kilminster, B.; Lawson, I.; Liao, J.; López, M.; Molina, J.; Moreno-Granados, G.; Pena, J.; Privitera, P.; Sarkis, Y.; Scarpine, V.; Schwarz, T.; Sofo Haro, M.; Tiffenberg, J.; Torres Machado, D.; Trillaud, F.; Yol, X.; Zhou, J.

2016-05-01

DAMIC (Dark Matter in CCDs) is an experiment searching for dark matter particles employing fully-depleted charge-coupled devices. Using the bulk silicon which composes the detector as target, we expect to observe coherent WIMP-nucleus elastic scattering. Although located in the SNOLAB laboratory, 2 km below the surface, the CCDs are not completely free of radioactive contamination, in particular coming from radon daughters or from the detector itself. We present novel techniques for the measurement of the radioactive contamination in the bulk silicon and on the surface of DAMIC CCDs. Limits on the Uranium and Thorium contamination as well as on the cosmogenic isotope 32 Si, intrinsically present on the detector, were performed. We have obtained upper limits on the 238 TJ (232 Th) decay rate of 5 (15) kg_1 d_1 at 95% CL. Pairs of spatially correlated electron tracks expected from 32 Si-32 P and 210 Pb-210 Bi beta decays were also measured. We have found a decay rate of 80+l10 -65 kg_1 d_1 for 32 Si and an upper limit of - 35 kg-1 d-1 for 210 Pb, both at 95% CL.

Segmented Ge detector rejection of internal beta activity produced by neutron irradiation

NASA Technical Reports Server (NTRS)

Varnell, L. S.; Callas, J. L.; Mahoney, W. A.; Pehl, R. H.; Landis, D. A.

1991-01-01

Future Ge spectrometers flown in space to observe cosmic gamma-ray sources will incorporate segmented detectors to reduce the background from radioactivity produced by energetic particle reactions. To demonstrate the effectiveness of a segmented Ge detector in rejecting background events due to the beta decay of internal radioactivity, a laboratory experiment has been carried out in which radioactivity was produced in the detector by neutron irradiation. A Cf-252 source of neutrons was used to produce, by neutron capture on Ge-74 (36.5 percent of natural Ge) in the detector itself, Ge-75 (t sub 1/2 = 82.78 min), which decays by beta emission with a maximum electron kinetic energy of 1188 keV. By requiring that an ionizing event deposit energy in two or more of the five segments of the detector, each about 1-cm thick, the beta particles, which have a range of about 1-mm, are rejected, while most external gamma rays incident on the detector are counted. Analysis of this experiment indicates that over 85 percent of the beta events from the decay of Ge-75 are rejected, which is in good agreement with Monte Carlo calculations.

Automatic measurements and computations for radiochemical analyses

USGS Publications Warehouse

Rosholt, J.N.; Dooley, J.R.

1960-01-01

In natural radioactive sources the most important radioactive daughter products useful for geochemical studies are protactinium-231, the alpha-emitting thorium isotopes, and the radium isotopes. To resolve the abundances of these thorium and radium isotopes by their characteristic decay and growth patterns, a large number of repeated alpha activity measurements on the two chemically separated elements were made over extended periods of time. Alpha scintillation counting with automatic measurements and sample changing is used to obtain the basic count data. Generation of the required theoretical decay and growth functions, varying with time, and the least squares solution of the overdetermined simultaneous count rate equations are done with a digital computer. Examples of the complex count rate equations which may be solved and results of a natural sample containing four ??-emitting isotopes of thorium are illustrated. These methods facilitate the determination of the radioactive sources on the large scale required for many geochemical investigations.

Coosa River Storage Annex, Talladega, Alabama. Environmental Investigation Report. Volume 1 of 2

DTIC Science & Technology

1992-09-01

radon and radon daughters using an alpha track detector; and the interior surfaces of six igloos were analyzed for the presence of polychlorinated...ATSDR, 1990]. Radon gas is a health hazard due to its radioactive transformation or decay into radioactive by- products or radon daughters . As radon

UNESCO Chemistry Teaching Project in Asia: Experiments on Nuclear Science.

ERIC Educational Resources Information Center

Dhabanandana, Salag

This teacher's guide on nuclear science is divided into two parts. The first part is a discussion of some of the concepts in nuclear chemistry including radioactivity, types of disintegration, radioactive decay and growth, and tracer techniques. The relevant experiments involving the use of radioisotopes are presented in the second part. The…

Secondary wind transport of radioactive materials after the Fukushima accident

NASA Astrophysics Data System (ADS)

Yamauchi, M.

2012-01-01

Data from the radiation monitoring network surrounding the Fukushima Dai-ichi Nuclear Power Plant (FNPP) revealed that the radiation levels generally decayed faster at a highly-contaminated area than at neighboring moderately-contaminated areas during the first month after the Fukushima nuclear accident in March, 2011. Two possible mechanisms are considered: secondary transport of radioactive dust by wind or rain, and nonuniform radionuclide ratio of contamination between radioiodine (131I) and radiocesium (134Cs and 137Cs). The composition data from soil does not favor the latter scenario, except for the local coastal region south of the FNPP, while inter-regional transport from the highly-contaminated area to the moderately-contaminated areas explains both the general difference in the decay rate in the entire area and the relatively slow decay at a high-dose rate anomaly 40 km northwest of the FNPP.

Quantitative imaging of disease signatures through radioactive decay signal conversion

PubMed Central

Thorek, Daniel LJ; Ogirala, Anuja; Beattie, Bradley J; Grimm, Jan

2013-01-01

In the era of personalized medicine there is an urgent need for in vivo techniques able to sensitively detect and quantify molecular activities. Sensitive imaging of gamma rays is widely used, but radioactive decay is a physical constant and signal is independent of biological interactions. Here we introduce a framework of novel targeted and activatable probes excited by a nuclear decay-derived signal to identify and measure molecular signatures of disease. This was accomplished utilizing Cerenkov luminescence (CL), the light produced by β-emitting radionuclides such as clinical positron emission tomography (PET) tracers. Disease markers were detected using nanoparticles to produce secondary Cerenkov-induced fluorescence. This approach reduces background signal compared to conventional fluorescence imaging. In addition to information from a PET scan, we demonstrate novel medical utility by quantitatively determining prognostically relevant enzymatic activity. This technique can be applied to monitor other markers and facilitates a shift towards activatable nuclear medicine agents. PMID:24013701

PsbS is required for systemic acquired acclimation and post-excess-light-stress optimization of chlorophyll fluorescence decay times in Arabidopsis

PubMed Central

Ciszak, Kamil; Kulasek, Milena; Barczak, Anna; Grzelak, Justyna; Maćkowski, Sebastian; Karpiński, Stanisław

2015-01-01

Systemic acquired acclimation (SAA) is an important light acclimatory mechanism that depends on the global adjustments of non-photochemical quenching and chloroplast retrograde signaling. As the exact regulation of these processes is not known, we measured time-resolved fluorescence of chlorophyll a in Arabidopsis thaliana leaves exposed to excess light, in leaves undergoing SAA, and in leaves after excess light episode. We compare the behavior induced in wild-type plants with null mutant of non-photochemical quenching (npq4–1). The wild type rosettes exhibit a small reduction of fluorescence decay times in leaves directly exposed to excess light and in leaves undergoing SAA in ambient low light. However in npq4–1 exposition to excess light results in much faster fluorescence decay, which is insensitive to excitation power. At the same time npq4–1 leaves undergoing SAA displayed intermediate fluorescence decay. The npq4–1 plants also lost the ability to optimize florescence decay, and thus chlorophyll a dynamics up to 2 h after excess light episode. The fluorescence decay dynamics in both WT and npq4–1 can be described by a set of 3 maximum decay times. Based on the results, we concluded that functional PsbS is required for optimization of absorbed photon fate and optimal light acclimatory responses such as SAA or after excess light stress. PMID:25654166

Linear Transformation Method for Multinuclide Decay Calculation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding Yuan

2010-12-29

A linear transformation method for generic multinuclide decay calculations is presented together with its properties and implications. The method takes advantage of the linear form of the decay solution N(t) = F(t)N{sub 0}, where N(t) is a column vector that represents the numbers of atoms of the radioactive nuclides in the decay chain, N{sub 0} is the initial value vector of N(t), and F(t) is a lower triangular matrix whose time-dependent elements are independent of the initial values of the system.

Radiation protection considerations along a radioactive ion beam transport line

NASA Astrophysics Data System (ADS)

Sarchiapone, Lucia; Zafiropoulos, Demetre

2016-09-01

The goal of the SPES project is to produce accelerated radioactive ion beams for Physics studies at “Laboratori Nazionali di Legnaro” (INFN, Italy). This accelerator complex is scheduled to be built by 2016 for an effective operation in 2017. Radioactive species are produced in a uranium carbide target, by the interaction of 200 μA of protons at 40 MeV. All of the ionized species in the 1+ state come out of the target (ISOL method), and pass through a Wien filter for a first selection and an HMRS (high mass resolution spectrometer). Then they are transported by an electrostatic beam line toward a charge state breeder (where the 1+ to n+ multi-ionization takes place) before selection and reacceleration at the already existing superconducting linac. The work concerning dose evaluations, activation calculation, and radiation protection constraints related to the transport of the radioactive ion beam (RIB) from the target to the mass separator will be described in this paper. The FLUKA code has been used as tool for those calculations needing Monte Carlo simulations, in particular for the evaluation of the dose rate due to the presence of the radioactive beam in the selection/interaction points. The time evolution of a radionuclide inventory can be computed online with FLUKA for arbitrary irradiation profiles and decay times. The activity evolution is analytically evaluated through the implementation of the Bateman equations. Furthermore, the generation and transport of decay radiation (limited to gamma, beta- and beta+ emissions) is possible, referring to a dedicated database of decay emissions using mostly information obtained from NNDC, sometimes supplemented with other data and checked for consistency. When the use of Monte Carlo simulations was not feasible, the Bateman equations, or possible simplifications, have been used directly.

Piezonuclear battery

DOEpatents

Bongianni, Wayne L.

1992-01-01

A piezonuclear battery generates output power arising from the piezoelectric voltage produced from radioactive decay particles interacting with a piezoelectric medium. Radioactive particle energy may directly create an acoustic wave in the piezoelectric medium or a moderator may be used to generate collision particles for interacting with the medium. In one embodiment a radioactive material (.sup.252 Cf) with an output of about 1 microwatt produced a 12 nanowatt output (1.2% conversion efficiency) from a piezoelectric copolymer of vinylidene fluoride/trifluorethylene.

Finding the Age of the Earth by Physics or by Faith?

ERIC Educational Resources Information Center

Brush, Stephen G.

1982-01-01

Refutes scientific creationists' arguments that the earth is less than 10,000 years old by presenting information related to the time scales for creation and evolution models, times from stellar distances, Kelvin's estimate of the earth's age, radioactive decay, radiometric dating, and the decay of the earth's magnetic field. (DC)

Neutrinos

NASA Astrophysics Data System (ADS)

Winter, K.; Murdin, P.

2000-11-01

Neutrinos are electrically neutral ELEMENTARY PARTICLES which experience only the weak nuclear force and gravity. Their existence was introduced as a hypothesis by Wolfgang Pauli in 1930 to explain the apparent violation of energy conservation in radioactive beta decay. Chadwick had discovered in 1914 that the energy spectrum of electrons emitted in beta decay was not monoenergetic but continuous...

Representative Atmospheric Plume Development for Elevated Releases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eslinger, Paul W.; Lowrey, Justin D.; McIntyre, Justin I.

2014-02-01

An atmospheric explosion of a low-yield nuclear device will produce a large number of radioactive isotopes, some of which can be measured with airborne detection systems. However, properly equipped aircraft may not arrive in the region where an explosion occurred for a number of hours after the event. Atmospheric conditions will have caused the radioactive plume to move and diffuse before the aircraft arrives. The science behind predicting atmospheric plume movement has advanced enough that the location of the maximum concentrations in the plume can be determined reasonably accurately in real time, or near real time. Given the assumption thatmore » an aircraft can follow a plume, this study addresses the amount of atmospheric dilution expected to occur in a representative plume as a function of time past the release event. The approach models atmospheric transport of hypothetical releases from a single location for every day in a year using the publically available HYSPLIT code. The effective dilution factors for the point of maximum concentration in an elevated plume based on a release of a non-decaying, non-depositing tracer can vary by orders of magnitude depending on the day of the release, even for the same number of hours after the release event. However, the median of the dilution factors based on releases for 365 consecutive days at one site follows a power law relationship in time, as shown in Figure S-1. The relationship is good enough to provide a general rule of thumb for estimating typical future dilution factors in a plume starting at the same point. However, the coefficients of the power law function may vary for different release point locations. Radioactive decay causes the effective dilution factors to decrease more quickly with the time past the release event than the dilution factors based on a non-decaying tracer. An analytical expression for the dilution factors of isotopes with different half-lives can be developed given the power law expression for the non-decaying tracer. If the power-law equation for the median dilution factor, Df, based on a non-decaying tracer has the general form Df=a(×t)^(-b) for time t after the release event, then the equation has the form Df=e^(-λt)×a×t^(-b) for a radioactive isotope, where λ is the decay constant for the isotope.« less

A kinematic-based methodology for radiological protection: Runoff analysis to calculate the effective dose for internal exposure caused by ingestion of radioactive isotopes

NASA Astrophysics Data System (ADS)

Sasaki, Syota; Yamada, Tadashi; Yamada, Tomohito J.

2014-05-01

We aim to propose a kinematic-based methodology similar with runoff analysis for readily understandable radiological protection. A merit of this methodology is to produce sufficiently accurate effective doses by basic analysis. The great earthquake attacked the north-east area in Japan on March 11, 2011. The system of electrical facilities to control Fukushima Daiichi nuclear power plant was completely destroyed by the following tsunamis. From the damaged reactor containment vessels, an amount of radioactive isotopes had leaked and been diffused in the vicinity of the plant. Radiological internal exposure caused by ingestion of food containing radioactive isotopes has become an issue of great interest to the public, and has caused excessive anxiety because of a deficiency of fundamental knowledge concerning radioactivity. Concentrations of radioactivity in the human body and internal exposure have been studied extensively. Previous radiologic studies, for example, studies by International Commission on Radiological Protection(ICRP), employ a large-scale computational simulation including actual mechanism of metabolism in the human body. While computational simulation is a standard method for calculating exposure doses among radiology specialists, these methods, although exact, are too difficult for non-specialists to grasp the whole image owing to the sophistication. In this study, the human body is treated as a vessel. The number of radioactive atoms in the human body can be described by an equation of continuity, which is the only governing equation. Half-life, the period of time required for the amount of a substance decreases by half, is only parameter to calculate the number of radioactive isotopes in the human body. Half-life depends only on the kinds of nuclides, there are no arbitrary parameters. It is known that the number of radioactive isotopes decrease exponentially by radioactive decay (physical outflow). It is also known that radioactive isotopes decrease exponentially by excretion (biological outflow). The total outflow is the sum of physical outflow and biological outflow. As a result, the number of radioactive atoms in the human body also decreases exponentially. Half-life can be determined by outflow flux from the definition. Intensity of radioactivity is linear respect to the number of radioactive atoms, both are equivalent analytically. Internal total exposure can be calculated by the time integral of intensity of radioactivity. The absorbed energy into the human body per radioactive decay and the effective dose are calculated by aid of Fermi's theory of beta decay and special relativity. The effective doses calculated by the present method almost agree with those of a study by ICRP. The present method shows that standard limit in general foods for radioactive cesium enforced in Japan, 100 Bq/kg, is too excessive. When we eat foods which contain cesium-137 of 100 Bq/kg at 1 kg/d during 50 years, we receive the effective dose less than natural exposure. Similarly, it is shown that we cannot find significant health damage medically and statistically by ingestion of rice which is harvested from a paddy field deposited current (January, 2014) radioactive cesium.

Science with radioactive beams: the alchemist's dream

NASA Astrophysics Data System (ADS)

Gelletly, W.

2001-05-01

Nuclear science is being transformed by a new capacity to create beams of radioactive nuclei. Until now all of our knowledge of nuclear physics and the applications which flow from it has been derived from studies of radioactive decay and nuclear reactions induced by beams of the 283 stable or long-lived nuclear species we can find on Earth. Here we describe first how beams of radioactive nuclei can be created. The present status of nuclear physics is then reviewed before potential applications to nuclear physics, nuclear astrophysics, materials science, bio-medical, and environmental studies are described.

Direct Observation of Two Proton Radioactivity Using Digital Photography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rykaczewski, Krzysztof Piotr; Pfutzner, M.; Dominik, Wojciech

2007-01-01

Recently the observation of a new type of spontaneous radioactive decay has been claimed in which two protons are simultaneously ejected by an atomic nucleus from the ground state1,2,3. Experimental data obtained for the extremely neutron-deficient nuclei 45Fe and 54Zn, were interpreted as the first evidence of such a decay mode which has been sought since 1960.4 However, the technique applied in those studies allowed only measurements of the decay time and the total energy released. Particles emitted in the decay were not identified and the conclusions had to be supported by theoretical arguments. Here we show for the firstmore » time, directly and unambiguously, that 45Fe indeed disintegrates by two-proton decay. Furthermore, we demonstrate that the decay branch of this isotope leads to various particle emission channels including two-proton and three-proton emission. To achieve this result we have developed a new type of detector V the Optical Time Projection Chamber (OTPC) in which digital photography is applied to nuclear physics for the first time. The detector records images of tracks from charged particles, allowing for their unambiguous identification and the reconstruction of decay events in three dimensions. This new and simple technique provides a powerful method to identify exotic decay channels involving emission of charged particles. It is expected that further studies with the OTPC device will yield important information on nuclei located at and beyond the proton drip-line, thus providing new material for testing and improving models of very unstable atomic nuclei.« less

18Ne Excited States Two-Proton Decay

NASA Astrophysics Data System (ADS)

de Napoli, M.; Rapisarda, E.; Raciti, G.; Cardella, G.; Amorini, F.; Giacoppo, F.; Sfienti, C.

2008-04-01

Two-proton radioactivity studies have been performed on excited states of 18Ne produced by 20Ne fragmentation at the FRS of the Laboratori Nazionali del Sud and excited via Coulomb excitation on a 209Pb target. The 18Ne levels decay has been studied by complete kinematical reconstruction. In spite of the low statistic, the energy and angular correlations of the emitted proton pairs indicate the presence of 2He emission toghether with the democratic decay.

Surface charge accumulation of particles containing radionuclides in open air

DOE PAGES

Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

2015-05-01

Radioactivity can induce charge accumulation on radioactive particles. But, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. Moreover, a charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify themore » particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. Our study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.« less

Radioactive liquid wastes discharged to ground in the 200 Areas during 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, J. D.; Poremba, B. E.

1979-03-26

This document is issued quarterly for the purpose of summarizing the radioactive liquid wastes that have been discharged to the ground in the 200 Areas. In addition to data for 1978, cumulative data since plant startup are presented. Also, in this document is a listing of decayed activity to the various plant sites.

10 CFR 72.104 - Criteria for radioactive materials in effluents and direct radiation from an ISFSI or MRS.

Code of Federal Regulations, 2014 CFR

2014-01-01

... radiation from an ISFSI or MRS. 72.104 Section 72.104 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED... materials in effluents and direct radiation from an ISFSI or MRS. (a) During normal operations and... radioactive materials, radon and its decay products excepted, to the general environment, (2) Direct radiation...

10 CFR 72.104 - Criteria for radioactive materials in effluents and direct radiation from an ISFSI or MRS.

Code of Federal Regulations, 2012 CFR

2012-01-01

... radiation from an ISFSI or MRS. 72.104 Section 72.104 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED... materials in effluents and direct radiation from an ISFSI or MRS. (a) During normal operations and... radioactive materials, radon and its decay products excepted, to the general environment, (2) Direct radiation...

10 CFR 72.104 - Criteria for radioactive materials in effluents and direct radiation from an ISFSI or MRS.

Code of Federal Regulations, 2013 CFR

2013-01-01

... radiation from an ISFSI or MRS. 72.104 Section 72.104 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED... materials in effluents and direct radiation from an ISFSI or MRS. (a) During normal operations and... radioactive materials, radon and its decay products excepted, to the general environment, (2) Direct radiation...

Modeling Radioactive Decay Chains with Branching Fraction Uncertainties

DTIC Science & Technology

2013-03-01

moments methods with transmutation matrices. Uncertainty from both half-lives and branching fractions is carried through these calculations by Monte...moment methods, method for sampling from normal distributions for half- life uncertainty, and use of transmutation matrices were leveraged. This...distributions for half-life and branching fraction uncertainties, building decay chains and generating the transmutation matrix (T-matrix

Natural radioactivity of the tar-sand deposits of Ondo State, Southwestern Nigeria

NASA Astrophysics Data System (ADS)

Fasasi, M. K.; Oyawale, A. A.; Mokobia, C. E.; Tchokossa, P.; Ajayi, T. R.; Balogun, F. A.

2003-06-01

A combination of gamma spectrometry and energy dispersive X-ray fluorescence was used to determine the presence and level of radioactivity of radionuclides in bituminous sand and overburden obtained from bituminous sand deposits in Ondo State Nigeria for the purpose of providing baseline data and assessing its impact on the environment. The radionuclides identified with reliable regularity belong to the decay series of naturally occurring radionuclides headed by 238U and 232Th. The non-decay series of naturally occurring 40K was found to be below the limit of detection. The average specific activity concentration values obtained for 214 Bi, 208Tl, and 226Ra in the overburden are 165.64±2.91, 150.25±2.91 and 60.97±2.27 Bq kg -1, respectively. The measured activity in the bituminous sand layer is so low that it can be said to be non-radioactive. The result of the EDXRF supports the presence of radioelements in the overburden, which are likely to be embedded in accessory minerals like zircon and tourmaline. Thus, surface exploration technique using soil-gas radon measurement will not yield the desired result. Furthermore, the level of radioelements and associated decay daughter 222Rn is not expected to cause any health hazard.

Laser-induced caesium-137 decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barmina, E V; Simakin, A V; Shafeev, G A

2014-08-31

Experimental data are presented on the laser-induced beta decay of caesium-137. We demonstrate that the exposure of a gold target to a copper vapour laser beam (wavelengths of 510.6 and 578.2 nm, pulse duration of 15 ns) for 2 h in an aqueous solution of a caesium-137 salt reduces the caesium-137 activity by 70%, as assessed from the gamma activity of the daughter nucleus {sup 137m}Ba, and discuss potential applications of laser-induced caesium-137 decay in radioactive waste disposal. (letters)

Electroplating method for producing ultralow-mass fissionable deposits

DOEpatents

Ruddy, Francis H.

1989-01-01

A method for producing ultralow-mass fissionable deposits for nuclear reactor dosimetry is described, including the steps of holding a radioactive parent until the radioactive parent reaches secular equilibrium with a daughter isotope, chemically separating the daughter from the parent, electroplating the daughter on a suitable substrate, and holding the electroplated daughter until the daughter decays to the fissionable deposit.

Radiation-induced microcrystal shape change as a mechanism of wasteform degradation

NASA Astrophysics Data System (ADS)

Ojovan, Michael I.; Burakov, Boris E.; Lee, William E.

2018-04-01

Experiments with actinide-containing insulating wasteforms such as devitrified glasses containing 244Cm, Ti-pyrochlore, single-phase La-monazite, Pu-monazite ceramics, Eu-monazite and zircon single crystals containing 238Pu indicate that mechanical self-irradiation-induced destruction may not reveal itself for many years (even decades). The mechanisms causing these slowly-occurring changes remain unknown therefore in addition to known mechanisms of wasteform degradation such as matrix swelling and loss of solid solution we have modelled the damaging effects of electrical fields induced by the decay of radionuclides in clusters embedded in a non-conducting matrix. Three effects were important: (i) electric breakdown; (ii) cluster shape change due to dipole interaction, and (iii) cluster shape change due to polarisation interaction. We reveal a critical size of radioactive clusters in non-conducting matrices so that the matrix material can be damaged if clusters are larger than this critical size. The most important parameters that control the matrix integrity are the radioactive cluster (inhomogeneity) size, specific radioactivity, and effective matrix electrical conductivity. We conclude that the wasteform should be as homogeneous as possible and even electrically conductive to avoid potential damage caused by electrical charges induced by radioactive decay.

Metabolism of 2-chloro-1,1-difluoroethene to glyoxylic and glycolic acid in rat hepatic microsomes.

PubMed

Baker, M T; Vasquez, M T; Bates, J N; Chiang, C K

1990-01-01

The complete metabolic fate of the volatile anesthetic halothane is unclear since 2-chloro-1,1-diflurorethene (CDE), a reductive halothane metabolite, is known to readily release inorganic fluoride upon oxidation by cytochrome P-450. This study sought to clarify the metabolism of CDE by determining its metabolites and the roles of induce cytochrome P-450 forms in its metabolism. Upon incubation of [14C]CDE with rat hepatic microsomes, two major radioactive products were found which accounted for greater than 94% of the total metabolites. These compounds were determined to be the nonhalogenated compounds, glyoxylic and glycolic acids, which were formed in a ratio of approximately 1 to 2 of glyoxylic to glycolic acid. No other radioactive metabolites could be detected. Following incubation of CDE with hepatic microsomes isolated from rats treated with cytochrome P-450 inducers, measurement of fluoride release showed that phenobarbital induced CDE metabolism to the greatest degree at high CDE levels, isoniazid was the most effective inducer at low CDE concentrations, and beta-naphthoflavone was ineffective as an inducer. These results suggest that CDE biotransformation primarily involves the generation of an epoxide intermediate, which undergoes mechanisms of decay leading to total dehalogenation of the molecule, and that this metabolism is preferentially carried out by the phenobarbital- and ethanol-inducible forms of cytochrome P-450.

Dual Neutral Particle Beam Interrogation of Intermodal Shipping Containers for Special Nuclear Material

NASA Astrophysics Data System (ADS)

Keith, Rodney Lyman

Intermodal shipping containers entering the United States provide an avenue to smuggle unsecured or stolen special nuclear material (SNM). The only direct method fielded to indicate the presence of SNM is by passive photon/neutron radiation detection. Active interrogation using neutral particle beams to induce fission in SNM is a method under consideration. One by-product of fission is the creation of fragments that undergo radioactive decay over a time period on the order of tens of seconds after the initial event. The "delayed" gamma-rays emitted from these fragments over this period are considered a hallmark for the presence of SNM. A fundamental model is developed using homogenized cargos with a SNM target embedded at the center and computationally interrogated using simultaneous neutron and photon beams. Findings from analysis of the delayed gamma emissions from these experiments are intended to mitigate the effects of poor quality information about the composition and disposition of suspect cargo before examination in an active interrogation portal.

Search for water and life's building blocks in the universe: A summary

NASA Astrophysics Data System (ADS)

Bergin, Edwin A.

Water and organics need to be supplied to terrestrial worlds like our own to provide the essential compounds required for the origin of life. These molecules form initially during the earliest stages of stellar birth, are supplied by collapse to the planet-forming disk predominantly as ice, and may undergo significant processing during this collapse and within large planetesimals that are heated via radioactive decay. Water and organic carriers can be quite volatile, thus their survival as ices within rocks is not preordained. In this focus meeting our goal is to bring together astronomers, cosmochemists, planetary scientists, chemical physicists, and spectroscopists who each explore individual aspects of this problem. In this summary we discuss some of the main themes that appeared in the meeting. Ultimately, cross-field collaboration is needed to provide greater understanding of the likelihood that terrestrial worlds form with these key compounds readily available on their surfaces - and are hence habitable if present at the right distance from the star.

The effectiveness of wastewater treatment in nuclear medicine: Performance data and radioecological considerations.

PubMed

Sudbrock, F; Schomäcker, K; Drzezga, A

2017-01-01

For planned and ongoing storage of liquid radioactive waste in a designated plant for a nuclear medicine therapy ward (decontamination system/decay system), detailed knowledge of basic parameters such as the amount of radioactivity and the necessary decay time in the plant is required. The design of the plant at the Department of Nuclear Medicine of the University of Cologne, built in 2001, was based on assumptions about the individual discharge of activity from patients, which we can now retrospectively validate. The decontamination factor of the plant is at present in the order of 10 -9 for 131 I. The annual discharges have been continuously reduced over the period of operation and are now in the region of a few kilobecquerels. This work emphasizes the high efficacy of the decontamination plant to reduce the amount of radioactivity released from the nuclear medicine ward into the environment to almost negligible levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gold coated lanthanide phosphate nanoparticles for targeted alpha generator radiotherapy.

PubMed

McLaughlin, Mark F; Woodward, Jonathan; Boll, Rose A; Wall, Jonathan S; Rondinone, Adam J; Kennel, Stephen J; Mirzadeh, Saed; Robertson, J David

2013-01-01

Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo α-generator targeted radiotherapies can deliver multiple α particles to a receptor site dramatically amplifying the radiation dose delivered to the target. The major challenge with α-generator radiotherapies is that traditional chelating moieties are unable to sequester the radioactive daughters in the bioconjugate which is critical to minimize toxicity to healthy, non-target tissue. The recoil energy of the (225)Ac daughters following α decay will sever any metal-ligand bond used to form the bioconjugate. This work demonstrates that an engineered multilayered nanoparticle-antibody conjugate can deliver multiple α radiations and contain the decay daughters of (225)Ac while targeting biologically relevant receptors in a female BALB/c mouse model. These multi-shell nanoparticles combine the radiation resistance of lanthanide phosphate to contain (225)Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established gold chemistry for attachment of targeting moieties.

Using Analogue Computers in Schools

ERIC Educational Resources Information Center

Hinson, D. J.

1974-01-01

Discusses the procedures of using operational amplifiers to conduct student projects and teach physical phenomena such as oscillation, radioactive decay, terminal velocity, projectile and ball bouncing. (CC)

Chemical purification of lanthanides for low-background experiments

NASA Astrophysics Data System (ADS)

Boiko, R. S.

2017-10-01

There are many potentially active isotopes among the lanthanide elements which are possible to use for low-background experiments to search for double β decay, dark matter, to investigate rare α and β decays. These kind of experiments require very low level of radioactive contamination, but commercially available compounds of lanthanides are always contamined by uranium, thorium, radium, potassium, etc. A simple chemical method based on liquid-liquid extraction has been applied for the purification of CeO2, Nd2O3 and Gd˙2O˙3 from radioactive traces. Detailed schemes of purification procedure are described. Measurements by using HPGe spectrometry demonstrate high efficiency in K, Ra, Th, U contaminations reduction on at least one order of magnitude.

Nuclear Data Sheets for A = 136

NASA Astrophysics Data System (ADS)

Sonzogni, A. A.

2002-04-01

Experimental data on ground-- and excited--state properties for all known nuclei with mass number A=136 have been compiled and evaluated. States populated in radioactive decay as well as in nuclear reactions have been considered. For these nuclei, level and decay schemes, as well as tables of nuclear properties are presented. This work supersedes the 1994 evaluation by J.K. Tuli (1994Tu01).

Nuclear Data Sheets for A = 230

DOE Office of Scientific and Technical Information (OSTI.GOV)

Browne, E.; Tuli, J. K.

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reactions for all isobars with mass number A=230. This evaluation includes the first experimental evidence of 230Am, produced through the 197Au(40Ar,3n)234Bk (α decay to 230Am) reaction, E(40Ar)=188.4 MeV (2003MoZX).

Kilonovae.

PubMed

Metzger, Brian D

2017-01-01

The mergers of double neutron star (NS-NS) and black hole (BH)-NS binaries are promising gravitational wave (GW) sources for Advanced LIGO and future GW detectors. The neutron-rich ejecta from such merger events undergoes rapid neutron capture ( r -process) nucleosynthesis, enriching our Galaxy with rare heavy elements like gold and platinum. The radioactive decay of these unstable nuclei also powers a rapidly evolving, supernova-like transient known as a "kilonova" (also known as "macronova"). Kilonovae are an approximately isotropic electromagnetic counterpart to the GW signal, which also provides a unique and direct probe of an important, if not dominant, r -process site. I review the history and physics of kilonovae, leading to the current paradigm of week-long emission with a spectral peak at near-infrared wavelengths. Using a simple light curve model to illustrate the basic physics, I introduce potentially important variations on this canonical picture, including: [Formula: see text]day-long optical ("blue") emission from lanthanide-free components of the ejecta; [Formula: see text]hour-long precursor UV/blue emission, powered by the decay of free neutrons in the outermost ejecta layers; and enhanced emission due to energy input from a long-lived central engine, such as an accreting BH or millisecond magnetar. I assess the prospects of kilonova detection following future GW detections of NS-NS/BH-NS mergers in light of the recent follow-up campaign of the LIGO binary BH-BH mergers.

Kilonovae

NASA Astrophysics Data System (ADS)

Metzger, Brian D.

2017-05-01

The mergers of double neutron star (NS-NS) and black hole (BH)-NS binaries are promising gravitational wave (GW) sources for Advanced LIGO and future GW detectors. The neutron-rich ejecta from such merger events undergoes rapid neutron capture ( r-process) nucleosynthesis, enriching our Galaxy with rare heavy elements like gold and platinum. The radioactive decay of these unstable nuclei also powers a rapidly evolving, supernova-like transient known as a "kilonova" (also known as "macronova"). Kilonovae are an approximately isotropic electromagnetic counterpart to the GW signal, which also provides a unique and direct probe of an important, if not dominant, r-process site. I review the history and physics of kilonovae, leading to the current paradigm of week-long emission with a spectral peak at near-infrared wavelengths. Using a simple light curve model to illustrate the basic physics, I introduce potentially important variations on this canonical picture, including: ˜ day-long optical ("blue") emission from lanthanide-free components of the ejecta; ˜ hour-long precursor UV/blue emission, powered by the decay of free neutrons in the outermost ejecta layers; and enhanced emission due to energy input from a long-lived central engine, such as an accreting BH or millisecond magnetar. I assess the prospects of kilonova detection following future GW detections of NS-NS/BH-NS mergers in light of the recent follow-up campaign of the LIGO binary BH-BH mergers.

Analysis of decay chains of superheavy nuclei produced in the 249Bk+48Ca and 243Am+48Ca reactions

NASA Astrophysics Data System (ADS)

Zlokazov, V. B.; Utyonkov, V. K.

2017-07-01

The analysis of decay chains starting at superheavy nuclei 293Ts and 289Mc is presented. The spectroscopic properties of nuclei identified during the experiments using the 249Bk+48Ca and 243Am+48Ca reactions studied at the gas-filled separators DGFRS, TASCA and BGS are considered. We present the analysis of decay data using widely adopted statistical methods and applying them to the short decay chains of parent odd-Z nuclei. We find out that the recently suggested method of analyzing decay chains by Forsberg et al may lead to questionable conclusions when applied for the analysis of radioactive decays. Our discussion demonstrates reasonable congruence of α-particle energies and decay times of nuclei assigned to isotopes 289Mc, 285Nh and 281Rg observed in both reactions.

Description of proton radioactivity using the Coulomb and proximity potential model for deformed nuclei

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Sukumaran, Indu

2017-09-01

Half-life predictions have been performed for the proton emitters with Z >50 in the ground state and isomeric state using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The agreement of the calculated values with the experimental data made it possible to predict some proton emissions that are not verified experimentally yet. For a comparison, the calculations also are performed using other theoretical models, such as the Gamow-like model of Zdeb et al. [Eur. Phys. J. A 52, 323 (2016), 10.1140/epja/i2016-16323-7], the semiempirical relation of Hatsukawa et al. [Phys. Rev. C 42, 674 (1990), 10.1103/PhysRevC.42.674], and the CPPM of Santhosh et al. [Pramana 58, 611 (2002)], 10.1007/s12043-002-0019-2. The Geiger-Nuttall law, originally observed for α decay, studied for proton radioactivity is found to work well provided it is plotted for the isotopes of a given proton emitter nuclide with the same ℓ value. The universal curve is found to be valid for proton radioactivity also as we obtained a single straight line for all proton emissions irrespective of the parents. Through the analysis of the experimentally measured half-lives of 44 proton emitters, the study revealed that the present systematic study lends support to a unified description for studying α decay, cluster radioactivity, and proton radioactivity.

Surface charge accumulation of particles containing radionuclides in open air.

PubMed

Kim, Yong-Ha; Yiacoumi, Sotira; Tsouris, Costas

2015-05-01

Radioactivity can induce charge accumulation on radioactive particles. However, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. A charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. The study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Late effect of subtotal thyroidectomy and radioactive iodine therapy on calcitonin secretion and bone mineral density in women treated for Graves' disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowery, W.D.; Thomas, C.G. Jr.; Awbrey, B.J.

1986-12-01

This study was designed to evaluate the effect of subtotal thyroidectomy and/or radioactive iodine therapy on plasma immunocalcitonin (iCT) levels and bone densities in patients treated for Graves' disease. Forty-eight women whose ages ranged from 29 to 79 years (mean, 55 years) were evaluated. All were at least 10 years beyond treatment. Fourteen patients had undergone subtotal thyroidectomy, 22 had received radioactive iodine therapy, and 12 had received both. Serum calcitonin levels were measured with the patient fasting and at 30 minutes and 2 hours after the ingestion of 15 mg of calcium in orange juice. Single photon absorptiometry wasmore » used to measure bone mineral density of the middle and distal radius. The mean fasting plasma levels of iCT for patients undergoing subtotal thyroidectomy was 27 +/- 2 mumol/L; women treated with radioactive iodine, 26 +/- 2; women undergoing subtotal thyroidectomy followed by radioactive iodine, 24 +/- 2, and for normal control women, 48.5 +/- 4.7. The mean stimulated iCT level of each of the patient groups was significantly lower than that of the normal controls (p = 0.01). There were no significant differences among the groups. Although there was an increased loss of bone mineral density in postmenopausal patients, with age and race as covariates, the bone densities of the distal radius in women undergoing subtotal thyroidectomy and/or receiving radioactive iodine were not significantly lower than those of normal control subjects (p greater than 0.05). These findings are consistent with other observations that patients treated by thyroidectomy and/or radioactive iodine for Graves' disease have lower basal levels of calcitonin and decreased calcitonin response to a provocative stimulus. Whether this loss of calcitonin reserve is a significant factor in development of postmenopausal osteoporosis remains unanswered.« less

Nuclear chemistry research and spectroscopy with radioactive sources. Sixteenth annual progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fink, R.W.

1980-10-31

Nuclear spectroscopic studies included the decay of /sup 201/Po to /sup 201/Bi, decay of /sup 201/At, decay of /sup 187/Au, and g/sub 7/2/ intruder band in /sup 109/Ag. A systematic comparison was conducted of the Interacting Boson-Fermion Approximation model predictions with experiment on neutron-deficient odd-A gold isotopes. An international comparison of /sup 133/Ba ..gamma..-ray standards was completed. L/sub 1/, L/sub 2/, and L/sub 3/ subshells were studied, and the decay energy of /sup 207/Bi is being measured. Carrier-free /sup 18/F has been prepared in crown ether solution. (DLC)

Double β-decay nuclear matrix elements for the A=48 and A=58 systems

NASA Astrophysics Data System (ADS)

Skouras, L. D.; Vergados, J. D.

1983-11-01

The nuclear matrix elements entering the double β decays of the 48Ca-48Ti and 58Ni-58Fe systems have been calculated using a realistic two nucleon interaction and realistic shell model spaces. Effective transition operators corresponding to a variety of gauge theory models have been considered. The stability of such matrix elements against variations of the nuclear parameters is examined. Appropriate lepton violating parameters are extracted from the A=48 data and predictions are made for the lifetimes of the positron decays of the A=58 system. RADIOACTIVITY Double β decay. Gauge theories. Lepton nonconservation. Neutrino mass. Shell model calculations.

Systematic study of cluster radioactivity of superheavy nuclei

NASA Astrophysics Data System (ADS)

Zhang, Y. L.; Wang, Y. Z.

2018-01-01

The probable cluster radioactivity (CR) of 294118, 296120, and 298122 is studied by using the unified description (UD) formula, universal (UNIV) curve, Horoi formula, and universal decay law (UDL). The predictions by the former three models suggest that the probable emitted clusters are lighter nuclei, and the calculations within the UDL formula give a different prediction: that both the lighter clusters and heavier ones can be emitted from the parent nuclei. A further study on the competition between α decay and CR of Z =104 -124 isotopes is performed. The former three models predict that α decay is the dominant decay mode, but the UDL formula suggests that CR dominates over α decay for Z ≥118 nuclei and the isotopes of 118 292 -296 ,308 -318 , 120 , 284 -304 ,308 -324 and 122-322316 are the most likely candidates as the cluster emitters. Because the former three formulas are just preformation models, the lighter cluster emissions can be described. However, the UDL formula can predict the lighter and heavier CR owing to the inclusion of the preformation and fissionlike mechanisms. Finally, it is found that the shortest CR half-lives are always obtained when the daughter nuclei are around the double magic 208Pb within the UDL formula, which indicates that shell effect has an important influence on CR.

The influence of particle size distribution on dose conversion factors for radon progeny in the underground excavations of hard coal mine.

PubMed

Skubacz, Krystian; Wojtecki, Łukasz; Urban, Paweł

2016-10-01

In Polish underground mines, hazards caused by enhanced natural radioactivity occur. The sources of radiation exposure are short-lived radon decay products, mine waters containing radium 226 Ra and 228 Ra and the radioactive sediments that can precipitate out of these waters. For miners, the greatest exposure is usually due to short-lived radon decay products. The risk assessment is based on the measurement of the total potential alpha energy concentration (PAEC) and the evaluation of the related dose by using the dose conversion factor as recommended by relevant legal requirements. This paper presents the results of measurements of particle size distributions of ambient aerosols in an underground hard coal mine, the assessment of the radioactive particle size distribution of the short-lived radon decay products and the corresponding values of dose conversion factors. The measurements of the ambient airborne particle size distribution were performed in the range from a few nanometers to about 20 μm. The study therefore included practically the whole class of respirable particles. The results showed that the high concentration of ultrafine and fine aerosols measured can significantly affect the value of the dose conversion factors, and consequently the corresponding committed effective dose, to which the miners can be exposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Astrophysics related programs at center for underground physics (CUP)

NASA Astrophysics Data System (ADS)

Kim, Yeongduk

2018-04-01

We are developing experimental programs related to particle astrophysics at the Center for Underground Physics (CUP); searching for neutrino-less double beta decay (0νββ) of 100Mo nuclei and sterile neutrinos in the mass range of eV using reactor neutrinos. Expected sensitivities of AMoRE double beta decay experiment and the results from recent NEOS experiment are described. Utilizing the facilities for ultra-low radioactivity measurement at the center, we are planning to measure the decay of 180mTa which is important to the nucleosynthesis of heavy nuclei.

Derivation of Soil Screening Guidelines for Gross Alpha/Beta Radioactivity for United States Air Force Deployment Sites

DTIC Science & Technology

2007-04-19

These levels are provided to assist in making decisions in case of a large accident. Assessment can be made based on what health effects can be...a beta particle to become polonium -214 (99.98% of decays), or it can emit an alpha particle to become thallium- 210 (0.02% of decays). Bismuth-214...lead- 210 , and polonium - 210 . A decay of bismuth-214 will eventually yield 5 alpha particles and 4 beta particles. Four radionuclides that occur in

Nuclear Data Sheets for A = 68

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCutchan, E. A.

2012-07-01

The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A = 68 mass chain have been reviewed. Nuclides ranging from Cr (Z = 24) to Br (Z = 35) are included. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are given. This work supersedes the previous evaluation of the data on these nuclides (2002Bu29).

Nuclear Data Sheets for A = 230

DOE Office of Scientific and Technical Information (OSTI.GOV)

Browne, E.; Tuli, J.K.

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reactions for all isobars with mass number A=230. This evaluation includes the first experimental evidence of {sup 230}Am, produced through the {sup 197}Au({sup 40}Ar,3n){sup 234}Bk ({alpha} decay to {sup 230}Am) reaction, E({sup 40}Ar)=188.4 MeV (2003MoZX).

Exotic Light Nuclei

ERIC Educational Resources Information Center

Cerny, Joseph; Poskanzer, Arthur M.

1978-01-01

Among the light elements, nuclei with unequal numbers of protons and neutrons are highly unstable. Some survive just long enough to be detected and exhibit unusual regimes of radioactive decay. ( Autor/MA)

Examining the possibility to observe neutron dark decay in nuclei

NASA Astrophysics Data System (ADS)

Pfützner, M.; Riisager, K.

2018-04-01

As proposed recently by Fornal and Grinstein, neutrons can undergo a dark matter decay mode which has not yet been observed. Such a decay could explain the existing discrepancy between two different methods of neutron lifetime measurements. If such neutron decay is possible, then it should occur also in nuclei with sufficiently low neutron binding energy. We examine a few nuclear candidates for the dark neutron decay and we consider the possibilities of their experimental identification. In more detail we discuss the case of 11Be which appears as the most promising nucleus for the observation of neutron dark decay.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rice, S.; Algora, A.; Tain, J. L.

The beta decays of Br-86 and Rb-91 have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the Ion Guide Isotope Separator On-Line facility in Jyvaskyla and further purified using the JYFLTRAP. Br-86 and Rb-91 are considered to be major contributors to the decay heat in reactors. In addition, Rb-91 was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decaywas well known from high-resolution measurements. Our results show that both decays were suffering from the Pandemoniummore » effect and that the results of Rudstam et al. should be renormalized. The relative impact of the studied decays in the prediction of the decay heat and antineutrino spectrum from reactors has been evaluated.« less

Radioactive contamination of scintillators

NASA Astrophysics Data System (ADS)

Danevich, F. A.; Tretyak, V. I.

2018-03-01

Low counting experiments (search for double β decay and dark matter particles, measurements of neutrino fluxes from different sources, search for hypothetical nuclear and subnuclear processes, low background α, β, γ spectrometry) require extremely low background of a detector. Scintillators are widely used to search for rare events both as conventional scintillation detectors and as cryogenic scintillating bolometers. Radioactive contamination of a scintillation material plays a key role to reach low level of background. Origin and nature of radioactive contamination of scintillators, experimental methods and results are reviewed. A programme to develop radiopure crystal scintillators for low counting experiments is discussed briefly.

RADIOACTIVE BATTERY

DOEpatents

Birden, J.H.; Jordan, K.C.

1959-11-17

A radioactive battery which includes a capsule containing the active material and a thermopile associated therewith is presented. The capsule is both a shield to stop the radiations and thereby make the battery safe to use, and an energy conventer. The intense radioactive decay taking place inside is converted to useful heat at the capsule surface. The heat is conducted to the hot thermojunctions of a thermopile. The cold junctions of the thermopile are thermally insulated from the heat source, so that a temperature difference occurs between the hot and cold junctions, causing an electrical current of a constant magnitude to flow.

Management of Ir-192 Disused Sealed Sources with Long-Lived Radioactive Contaminants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dellamano, Jose Claudio; Ferreira, Robson de Jesus; Potiens, Ademar Jose Jr.

2015-07-01

Iridium-192 sealed sources are the most widely used sealed source in industrial applications in Brazil. They are not recyclable and in the end of the useful life, they are discarded as radioactive waste. The recommended management strategy of this waste is decay in storage and disposal as exempt waste because the half-life is only 73.8 days. Presently, thousands of Ir- 192 sources are under storage waiting release. Surprisingly, sources that were under storage for more than ten years and for which no measurable contact dose rate was expected still present significant remaining radioactivity. The examination of the gamma spectra ofmore » these sources showed the presence of Co-60 and the gamma emission lines from the Ir-192m2 isomer, the metastable isotope with half-life of 241 years, which is also formed by the irradiation of natural iridium. The aim of the study reported in this paper is to characterize the Ir-192 disused sources under interim storage at the Radioactive Waste Management Department, considering the presence of minor contaminants in the irradiated iridium and the fraction of the total initial activity of the sources that is attributable to that metastable isotope. The radioactive inventories at the end of the irradiation and after the decay period were predicted using the Scale 6.0 code and the results were compared with activity measurements of the disused sources by gamma spectrometry. (authors)« less

Nuclear Data Sheets for A = 69

NASA Astrophysics Data System (ADS)

Nesaraja, C. D.

2014-01-01

Experimental data on ground- and excited-state properties for all known nuclei with mass number A = 69 have been compiled and evaluated. States populated in radioactive decay, as well as in nuclear reactions, have been considered. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are given in detail. This work supersedes the 2000 evaluation by M.R. Bhat and J.K. Tuli (2000Bh05).

Nuclear Data Sheets for A=69

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nesaraja, C.D.

Experimental data on ground– and excited–state properties for all known nuclei with mass number A=69 have been compiled and evaluated. States populated in radioactive decay, as well as in nuclear reactions, have been considered. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are given in detail. This work supersedes the 2000 evaluation by M.R. Bhat and J.K. Tuli (2000Bh05)

Radioactive cesium isotope ratios as a tool for determining dispersal and re-dispersal mechanisms downwind from the Nevada Nuclear Security Site.

PubMed

Snyder, Darin C; Delmore, James E; Tranter, Troy; Mann, Nick R; Abbott, Michael L; Olson, John E

2012-08-01

Fractionation of the two longer-lived radioactive cesium isotopes ((135)Cs and (137)Cs) produced by above ground nuclear tests have been measured and used to clarify the dispersal mechanisms of cesium deposited in the area between the Nevada Nuclear Security Site and Lake Mead in the southwestern United States. Fractionation of these isotopes is due to the 135-decay chain requiring several days to completely decay to (135)Cs, and the 137-decay chain less than one hour decay to (137)Cs. Since the Cs precursors are gases, iodine and xenon, the (135)Cs plume was deposited farther downwind than the (137)Cs plume. Sediment core samples were obtained from the Las Vegas arm of Lake Mead, sub-sampled and analyzed for (135)Cs/(137)Cs ratios by thermal ionization mass spectrometry. The layers proved to have nearly identical highly fractionated isotope ratios. This information is consistent with a model where the cesium was initially deposited onto the land area draining into Lake Mead and the composite from all of the above ground shots subsequently washed onto Lake Mead by high intensity rain and wind storms producing a layering of Cs activity, where each layer is a portion of the composite. Copyright © 2012 Elsevier Ltd. All rights reserved.

Physics Notes

ERIC Educational Resources Information Center

School Science Review, 1976

1976-01-01

Described are 13 physics experiments/demonstrations applicable to introductory physics courses. Activities include: improved current balance, division circuits, liquid pressure, convection, siphons, oscillators and modulation, electrical resistance, soap films, Helmholtz coils, radioactive decay, and springs. (SL)

Upgrade of the SPIRAL identification station for high-precision measurements of nuclear β decay

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Thomas, J. C.; Blank, B.; Bouzomita, H.; Austin, R. A. E.; Ball, G. C.; Bucaille, F.; Delahaye, P.; Finlay, P.; Frémont, G.; Gibelin, J.; Giovinazzo, J.; Grinyer, J.; Kurtukian-Nieto, T.; Laffoley, A. T.; Leach, K. G.; Lefèvre, A.; Legruel, F.; Lescalié, G.; Perez-Loureiro, D.

2014-03-01

The low-energy identification station at SPIRAL (Système de Production d'Ions Radioactifs Accélérés en Ligne) has been upgraded for studying the β decays of short-lived radioactive isotopes and to perform high-precision half-life and branching-ratio measurements for superallowed Fermi and isospin T=1/2 mirror β decays. These new capabilities, combined with an existing Paul trap setup for measurements of β-ν angular-correlation coefficients, provide a powerful facility for investigating fundamental properties of the electroweak interaction through nuclear β decays. A detailed description of the design study, construction, and first results obtained from an in-beam commissioning experiment on the β+ decays 14 O and 17F are presented.

Systematic investigation of cluster radioactivity for uranium isotopes

NASA Astrophysics Data System (ADS)

Seif, W. M.; Amer, Laila H.

2018-01-01

The most probable cluster decays that can be observed for 217-238U isotopes are investigated. We identified the more-probable decays that commonly manifest themselves via cold valleys in the driving potentials with respect to the mass number and the atomic number, individually. The calculations are performed using the Skyrme-SLy4 nucleon-nucleon interaction, within the frame work of the performed cluster model. Among the indicated favored decays that involve emitted light clusters heavier than α-particle, twenty six decay modes display calculated half-life less than 1022 years, with branching ratio larger than 10-14%. The estimated branching ratio for the α-decay of 237U, that did not observed yet, is B = 2.1 ×10-10% (Tα = 8.7 ×109 years). The indicated most probable decays that did not observed yet include the 22Ne decay of 232U, 25Ne and 32Si decays of 233U, 24Ne and 29Mg decays of 235U, and the 34Si and 30Mg decay modes of 238U, with 10-14 < B(%) <10-7.

Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

NASA Astrophysics Data System (ADS)

Trache, L.; Banu, A.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Spiridon, A.; Tribble, R. E.; Saastamoinen, A.; Jokinen, A.; Äysto, J.; Davinson, T.; Lotay, G.; Woods, P. J.; Pollacco, E.

2012-02-01

In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A&M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23Al, 27P, 31Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22Na(p,γ)23Mg (crucial for the depletion of 22Na in novae), 26mAl(p,γ)27Si and 30P(p,γ)31S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

Understanding the SNO+ Detector

DOE PAGES

Kamdin, K.

2015-03-24

SNO+, a large liquid scintillator experiment, is the successor of the Sudbury Neutrino Observatory (SNO) experiment. The scintillator volume will be loaded with large quantities of 130Te, an isotope that undergoes double beta decay, in order to search for neutrinoless double beta decay. In addition to this search, SNO+ has a broad physics program due to its sensitivity to solar and supernova neutrinos, as well as reactor and geo anti-neutrinos. SNO+ can also place competitive limits on certain modes of invisible nucleon decay during its first phase. The detector is currently undergoing commissioning in preparation for its first phase, inmore » which the detector is filled with ultra pure water. This will be followed by a pure scintillator phase, and then a Tellurium-loaded scintillator phase to search for neutrinoless double beta decay. Here we present the work done to model detector aging, which was first observed during SNO. The aging was found to reduce the optical response of the detector. We also describe early results from electronics calibration of SNO+.« less

Experimental study of the β decay of the very neutron-rich nucleus Ge 85

DOE PAGES

Korgul, A.; Rykaczewski, Krzysztof Piotr; Grzywacz, Robert Kazimierz; ...

2017-04-04

The β -decay properties of the very neutron-rich nucleus 85Ge, produced in the proton-induced fission of 238U, were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The level scheme of 33 85As 52 populated in 85Geβ γ decay was reconstructed and compared to shell-model calculations. The investigation of the systematics of low-energy levels in N =52 isotones together with shell-model analysis allowed us to provide an estimate of the low-energy structure of the more exotic N =52 isotone 81Cu.

Decay heat uncertainty quantification of MYRRHA

NASA Astrophysics Data System (ADS)

Fiorito, Luca; Buss, Oliver; Hoefer, Axel; Stankovskiy, Alexey; Eynde, Gert Van den

2017-09-01

MYRRHA is a lead-bismuth cooled MOX-fueled accelerator driven system (ADS) currently in the design phase at SCK·CEN in Belgium. The correct evaluation of the decay heat and of its uncertainty level is very important for the safety demonstration of the reactor. In the first part of this work we assessed the decay heat released by the MYRRHA core using the ALEPH-2 burnup code. The second part of the study focused on the nuclear data uncertainty and covariance propagation to the MYRRHA decay heat. Radioactive decay data, independent fission yield and cross section uncertainties/covariances were propagated using two nuclear data sampling codes, namely NUDUNA and SANDY. According to the results, 238U cross sections and fission yield data are the largest contributors to the MYRRHA decay heat uncertainty. The calculated uncertainty values are deemed acceptable from the safety point of view as they are well within the available regulatory limits.

Notes on Experiments.

ERIC Educational Resources Information Center

Physics Education, 1982

1982-01-01

Describes: (1) an apparatus which provides a simple method for measuring Stefan's constant; (2) a simple phase shifting circuit; (3) a radioactive decay computer program (for ZX81); and (4) phase difference between transformer voltages. (Author/JN)

Nuclear Data Sheets for A = 251–259 (odd)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Browne, E.; Tuli, J.K.

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reaction studies for all known nuclei with mass numbers A = 251, 253, 255, 257, and 259.

Gamma-Ray Spectroscopy at TRIUMF-ISAC

NASA Astrophysics Data System (ADS)

Garrett, P. E.; Svensson, C. E.; Ball, G. C.; Hackman, G.; Zganjar, E. F.; Andreoiu, C.; Andreyev, A.; Ashley, S. F.; Austin, R. A. E.; Bandyopadhyay, D.; Becker, J. A.; Chan, S.; Coombes, H.; Churchman, R.; Chakrawarthy, R. S.; Finlay, P.; Grinyer, G. F.; Hyland, B.; Illes, E.; Jones, G. A.; Kulp, W. D.; Leslie, J. R.; Mattoon, C.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Regan, P. H.; Ressler, J. J.; Sarazin, F.; Schumaker, M. A.; Schwarzenberg, J.; Smith, M. B.; Valiente-Dobón, J. J.; Walker, P. M.; Williams, S. J.; Waddington, J. C.; Watters, L. M.; Wong, J.; Wood, J. L.

2006-03-01

The 8π spectrometer at TRIUMF-ISAC consists of 20 Compton-suppressed germanium detectors and various auxiliary devices. The Ge array, once used for studies of nuclei at high angular momentum, has been transformed into the world's most powerful device dedicated to radioactive-decay studies. Many improvements in the spectrometer have been made, including a high-throughput data acquisition system, installation of a moving tape collector, incorporation of an array of 20 plastic scintillators for β-particle tagging, 5 Si(Li) detectors for conversion electrons, and 10 BaF2 detectors for fast-lifetime measurements. Experiments can be performed where data from all detectors are collected simultaneously, resulting in a very detailed view of the nucleus through radioactive decay. A number of experimental programmes have been launched that take advantage of the versatility of the spectrometer, and the intense beams available at TRIUMF-ISAC.

Radioxenon Production from an Underground Nuclear Detonation

NASA Astrophysics Data System (ADS)

Sun, Y.

2016-12-01

The Comprehensive Nuclear Test Ban Treaty of 1996 has sparked the attention of many nations around the world for detecting Underground Nuclear Explosions (UNEs). The radioisotopes, specifically isotopes of xenon, Xe-131m, Xe-133m, Xe-133, and Xe-135, are being studied using their half-lives and decay networks for distinguishing civilian nuclear applications from UNEs. This study aims to simulate radioxenon concentrations and their uncertainties using analytical solutions of radioactive decay networks.

Validation of the fission yield and decay data libraries with the 10 s-delayed 235 U fission γ-ray energy spectrum

NASA Astrophysics Data System (ADS)

Mendoza, E.; Álvarez-Velarde, F.; Bécares, V.; Cano-Ott, D.; González-Romero, E.; Martínez, T.; Villamarín, D.

2017-10-01

We have measured with a LaCl3 detector the γ-ray spectrum emitted by a 235 U enriched UO2 fuel rod 10 s after being irradiated with thermal neutrons. The experimental results are compared with simulations performed with the fission product yield and radioactive decay data libraries present in the most recent releases of ENDF/B, JEFF and JENDL.

Nuclear Data Sheets for A = 138

NASA Astrophysics Data System (ADS)

Sonzogni, A. A.

2003-03-01

Experimental data on ground- and excited-state properties for all known nuclei with mass number A=138 have been compiled and evaluated. States populated in radioactive decay as well as in nuclear reactions have been considered. For these nuclei, level and decay schemes, as well as tables of nuclear properties are given. This work supersedes the 1995 evaluation by J.K. Tuli (1995Tu01). Manuscripts published before December 2002 have been included in this work.

Estimation of aquifer radionuclide concentrations by postprocessing of conservative tracer model results

NASA Astrophysics Data System (ADS)

Gedeon, M.; Vandersteen, K.; Rogiers, B.

2012-04-01

Radionuclide concentrations in aquifers represent an important indicator in estimating the impact of a planned surface disposal for low and medium level short-lived radioactive waste in Belgium, developed by the Belgian Agency for Radioactive Waste and Enriched Fissile Materials (ONDRAF/NIRAS), who also coordinates and leads the corresponding research. Estimating aquifer concentrations for individual radionuclides represents a computational challenge because (a) different retardation values are applied to different hydrogeologic units and (b) sequential decay reactions with radionuclides of various sorption characteristics cause long computational times until a steady-state is reached. The presented work proposes a methodology reducing substantially the computational effort by postprocessing the results of a prior non-reactive tracer simulation. These advective transport results represent the steady-state concentration - source flux ratio and the break-through time at each modelling cell. These two variables are further used to estimate the individual radionuclide concentrations by (a) scaling the steady-state concentrations to the source fluxes of individual radionuclides; (b) applying the radioactive decay and ingrowth in a decay chain; (c) scaling the travel time by the retardation factor and (d) applying linear sorption. While all steps except (b) require solving simple linear equations, applying ingrowth of individual radionuclides in decay chains requires solving the differential Bateman equation. This equation needs to be solved once for a unit radionuclide activity at all arrival times found in the numerical grid. The ratios between the parent nuclide activity and the progeny activities are then used in the postprocessing. Results are presented for discrete points and examples of radioactive plume maps are given. These results compare well to the results achieved using a full numerical simulation including the respective chemical reaction processes. Although the proposed method represents a fast way to estimate the radionuclide concentrations without performing timely challenging simulations, its applicability has some limits. The radionuclide source needs to be assumed constant during the period of achieving a steady-state in the model. Otherwise, the source variability of individual radionuclides needs to be modelled using a numerical simulation. However, such a situation only occurs in cases of source variability in a period until steady-state is reached and such a simulation takes a relatively short time. The proposed method enables an effective estimation of individual radionuclide concentrations in the frame of performance assessment of a radioactive waste disposal. Reducing the calculation time to a minimum enables performing sensitivity and uncertainty analyses, testing alternative models, etc. thus enhancing the overall quality of the modelling analysis.

Precision Branching Ratio Measurement for the Superallowed β+ Emitter Ga62 and Isospin-Symmetry-Breaking Corrections in A≥62 Nuclei

NASA Astrophysics Data System (ADS)

Hyland, B.; Svensson, C. E.; Ball, G. C.; Leslie, J. R.; Achtzehn, T.; Albers, D.; Andreoiu, C.; Bricault, P.; Churchman, R.; Cross, D.; Dombsky, M.; Finlay, P.; Garrett, P. E.; Geppert, C.; Grinyer, G. F.; Hackman, G.; Hanemaayer, V.; Lassen, J.; Lavoie, J. P.; Melconian, D.; Morton, A. C.; Pearson, C. J.; Pearson, M. R.; Phillips, A. A.; Schumaker, M. A.; Smith, M. B.; Towner, I. S.; Valiente-Dobón, J. J.; Wendt, K.; Zganjar, E. F.

2006-09-01

A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator radioactive ion beam facility. Nineteen γ rays emitted following β+ decay of Ga62 were identified, establishing the dominant superallowed branching ratio to be (99.861±0.011)%. Combined with recent half-life and Q-value measurements, this branching ratio yields a superallowed ft value of 3075.6±1.4s for Ga62 decay. These results demonstrate the feasibility of high-precision superallowed branching ratio measurements in the A≥62 mass region and provide the first stringent tests of the large isospin-symmetry-breaking effects predicted for these decays.

Science Notes.

ERIC Educational Resources Information Center

Talbot, Chris; And Others

1991-01-01

Twenty science experiments are presented. Topics include recombinant DNA, physiology, nucleophiles, reactivity series, molar volume of gases, spreadsheets in chemistry, hydrogen bonding, composite materials, radioactive decay, magnetism, speed, charged particles, compression waves, heat transfer, Ursa Major, balloons, current, and expansion of…

Effect of enhanced ionizing radiation on the cloud electricity after the Fukushima nuclear accident

NASA Astrophysics Data System (ADS)

Yamauchi, Masatoshi; Takeda, Masahiko; Nagamachi, Shingo

2018-03-01

The vertical downward component of the DC atmospheric electric field, or potential gradient (PG), at Kakioka 150 km southwest of the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) was analyzed before and after the FNPP1 accident to examine possible influence of floating radioactive particles on the PG under the highly electrified clouds. Using 1-min PG data from March 13 to April 30 (late April 2011 corresponding to the time when floating radioactive materials decreased significantly) from 2006 to 2015, time profiles to/from the PG peaks (<- 100 or >+ 100 V/m) for 2011 are compared with other years. The PG developed toward and decays from its negative peaks faster in the first 50 days after the FNPP1 accident than for the same period in other years, making the 10-min averaged PG values for the same negative PG peak higher (smaller in terms of absolute value) during the first 50 days after the FNPP1 accident than those in other years in the study period, while the distribution of peak PG values is similar between 2011 and the other years. The observed shortening of the timescale is symmetric between the rise and decay and is the most clear when the negative PG peak is about - 200 to - 400 V/m. For positive peaks, the change of the baseline resulting from the radioactive contamination on the ground in 2011 caused superficial difference on such time profiles. Otherwise, there are no significant difference between 2011 and the other years. Possible explanations based on increased ionizing radiation from floating radioactive particles, which are found to be concentrated at low altitudes (< 500 m according to radiosonde in-situ observations of gamma rays) where negative cloud charges normally exceed positive charges, are discussed. The scenarios discussed include enhanced electrostatic shielding and electric conductivity-led decay rate of cloud charges. The result opens up a new possibility of using PG as an independent monitor of radioactivity at some altitudes in case of nuclear accidents.

Mechanisms of phosphene generation in ocular proton therapy as related to space radiation exposure

NASA Astrophysics Data System (ADS)

Chuard, D.; Anthonipillai, V.; Dendale, R.; Nauraye, C.; Khan, E.; Mabit, C.; De Marzi, L.; Narici, L.

2016-08-01

Particle therapy provides an opportunity to study the human response to space radiation in ground-based facilities. On this basis, a study of light flashes analogous to astronauts' phosphenes reported by patients undergoing ocular proton therapy has been undertaken. The influence of treatment parameters on phosphene generation was investigated for 430 patients treated for a choroidal melanoma at the proton therapy centre of the Institut Curie (ICPO) in Orsay, France, between 2008 and 2011. 60% of them report light flashes, which are predominantly (74%) blue. An analysis of variables describing the patient's physiology, properties of the tumour and dose distribution shows that two groups of tumour and beam variables are correlated with phosphene occurrence. Physiology is found to have no influence on flash triggering. Detailed correlation study eventually suggests a possible twofold mechanism of phosphene generation based on (i) indirect Cerenkov light in the bulk of the eye due to nuclear interactions and radioactive decay and (ii) direct excitation of the nerve fibres in the back of the eye and/or radical excess near the retina.

Combined effects of radiation damage and He accumulation on bubble nucleation in Gd2Ti2O7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Caitlin A.; Patel, Maulik K.; Aguiar, Jeffery A.

2016-10-01

Pyrochlores have long been considered as host phases for long-term immobilization of radioactive waste nuclides that would undergo ..alpha..-decay for hundreds of thousands of years. This work utilizes ion-beam irradiations to examine the combined effects of radiation damage and He accumulation on bubble formation in Gd2Ti2O7 over relevant waste-form timescales. Helium bubbles are not observed in pre-damaged Gd2Ti2O7 implanted with 2 x 1016 He/cm2, even after post-implantation irradiations with 7 MeV Au3+ at 300, 500, and 700 K. However, He bubbles with average diameters of 1.5 nm and 2.1 nm are observed in pre-damaged (amorphous) Gd2Ti2O7 and pristine Gd2Ti2O7, respectively,more » after implantation of 2 x 1017 He/cm2. The critical He concentration for bubble nucleation in Gd2Ti2O7 is estimated to be 6 at.% He.« less

Estimation of radioactive contamination of soils from the "Balapan" and the "Experimental field" technical areas of the Semipalatinsk nuclear test site.

PubMed

Evseeva, T; Belykh, E; Geras'kin, S; Majstrenko, T

2012-07-01

In spite of the long history of the research, radioactive contamination of the Semipalatinsk nuclear test site (SNTS) in the Republic of Kazakhstan has not been adequately characterized. Our cartographic investigation has demonstrated highly variable radioactive contamination of the SNTS. The Cs-137, Sr-90, Eu-152, Eu-154, Co-60, and Am-241 activity concentrations in soil samples from the "Balapan" site were 42.6-17646, 96-18250, 1.05-11222, 0.6-4865, 0.23-4893, and 1.2-1037 Bq kg(-1), correspondingly. Cs-137 and Sr-90 activity concentrations in soil samples from the "Experimental field" site were varied from 87 up to 400 and from 94 up to 1000 Bq kg(-1), respectively. Activity concentrations of Co-60, Eu-152, and Eu-154 were lower than the minimum detectable activity of the method used. Concentrations of naturally occurring radionuclides (K-40, Ra-226, U-238, and Th-232) in the majority of soil samples from the "Balapan" and the "Experimental field" sites did not exceed typical for surrounding of the SNTS areas levels. Estimation of risks associated with radioactive contamination based on the IAEA clearance levels for a number of key radionuclides in solid materials shows that soils sampled from the "Balapan" and the "Experimental field" sites might be considered as radioactive wastes. Decrease in specific activity of soil from the sites studied up to safety levels due to Co-60, Cs-137, Sr-90, Eu-152, Eu-154 radioactive decay and Am-241 accumulation-decay will occur not earlier than 100 years. In contrast, soils from the "Experimental field" and the "Balapan" sites (except 0.5-2.5 km distance from the "Chagan" explosion point) cannot be regarded as the radioactive wastes according safety norms valid in Russia and Kazakhstan. Copyright © 2012 Elsevier Ltd. All rights reserved.

[11C]metaraminol, a false neurotransmitter: preparation, metabolite studies and positron emission tomography examination in monkey.

PubMed

Någren, K; Halldin, C; Swahn, C G; Suhara, T; Farde, L

1996-04-01

No-carrier-added racemic [11C]metaraminol was prepared by a selective condensation of [11C]nitroethane with 3-hydroxy-benzaldehyde using tetrabutylammonium fluoride in tetrahydrofuran (THF) as a catalyst, followed by a reduction with Raney nickel in formic acid. [11C]Metaraminol was produced in 30 to 45% decay-corrected yield from [11C]nitroethane (13 to 20% decay corrected from [11C]CO2) within 45 to 55 min total synthesis time. Reversed phase high-performance liquid chromatography (HPLC) was used for the separation of the racemic erythro- and threo-forms of [11C]metaraminol. The radiochemical purity was higher than 98%, and the specific radioactivity at the end of synthesis was 500 to 800 Ci/mmol (18 to 30 GBq/mumol). Positron emission tomography (PET) examination of racemic erythro-[11C]metaraminol in a Cynomolgus monkey showed a high uptake of radioactivity in the heart. Following pretreatment with the selective norepinephrine reuptake inhibitor desipramine, the radioactivity uptake in the myocardium was markedly reduced (80%), demonstrating the specificity of erythro-[11C]metaraminol for the norepinephrine reuptake system of the heart. Pretreatment with desipramine had no effect on radioactivity in lung. The metabolism was rapid for [11C]metaraminol. The amounts of the total radioactivity representing [11C]metaraminol in plasma, determined by HPLC, were 14% at 6 min and 8% at 34 min. The high specific uptake of racemic erythro-[11C]metaraminol indicates that enantiomerically pure (R,S)-[11C]metaraminol has potential for detailed mapping of the sympathetic innervation of the human myocardium.

The Mean Life Squared Relationship for Abundances of Extinct Radioactivities

NASA Technical Reports Server (NTRS)

Lodders, K.; Cameron, A. G. W.

2004-01-01

We discovered that the abundances of now extinct radioactivities (relative to stable reference isotopes) in meteorites vary as a function of their mean lifetimes squared. This relationship applies to chondrites, achondrites, and irons but to calcium-aluminum inclusions (CAIs). Certain meteorites contain excesses in isotopic abundances from the decay of radioactive isotopes with half-lives much less than the age of the solar system. These short-lived radioactivities are now extinct, but they were alive when meteorites assembled in the early solar system. The origin of these radioactivities and the processes which control their abundances in the solar nebula are still not well understood. Some clues may come from our finding that the meteoritic abundances of now extinct radioactivities (relative to stable reference isotopes) vary as a function of their mean lifetimes squared. This relationship applies to chondrites, achondrites, and irons, but not to CAIs. This points to at least two different processes establishing the abundances of short-lived isotopes found in the meteoritic record.

Environmental Sensor Technologies and Procedures for Detecting and Identifying Indoor Air Pollution

DTIC Science & Technology

1992-03-01

problem of radon or biological contaminants. Radon daughters --the radioactive decay products of radon gas-are most dangerous when they attach to a...entry points. Radon itself decays into radon daughters which are dangerous when they bond with dust particles that allow them to embed in the lining...because it contains respirable particles to which radon daughters can attach and embed in the lungs. The most direct way to check the ETS level is to

Computer Series, 97.

ERIC Educational Resources Information Center

Kay, Jack G.; And Others

1988-01-01

Describes two applications of the microcomputer for laboratory exercises. Explores radioactive decay using the Batemen equations on a Macintosh computer. Provides examples and screen dumps of data. Investigates polymer configurations using a Monte Carlo simulation on an IBM personal computer. (MVL)

Synthesis of perbromates

NASA Technical Reports Server (NTRS)

Appelman, E. H.; Studier, M. H.

1969-01-01

Salts of heptavalent bromine were synthesized by a hot atom process, the beta decay of radioactive selenium-83 incorporated into a selenate. Formation of an unreactive perbromate ion led to preparation of macro amounts of perborate. A rubidium salt was isolated.

Nuclear Data Sheets for A = 245

DOE Office of Scientific and Technical Information (OSTI.GOV)

Browne, E.; Tuli,J.K.

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reaction studies for all nuclei with mass number A = 245. This evaluation revises the earlier one by Y.A. Akovali (1992Ak05).

The Majorana Demonstrator radioassay program

DOE PAGES

Abgrall, N.; Arnquist, I. J.; Avignone, F. T.; ...

2016-05-03

The Majorana collaboration is constructing the Majorana Demonstrator at the Sanford Underground Research Facility at the Homestake gold mine, in Lead, SD. The apparatus will use Ge detectors, enriched in isotope 76Ge, to demonstrate the feasibility of a large-scale Ge detector experiment to search for neutrinoless double beta decay. The long half-life of this postulated process requires that the apparatus be extremely low in radioactive isotopes whose decays may produce backgrounds to the search. The radioassay program conducted by the collaboration to ensure that the materials comprising the apparatus are sufficiently pure is described. The resulting measurements from gamma-ray counting,more » neutron activation and mass spectroscopy of the radioactive-isotope contamination for the materials studied for use in the detector are reported. In conclusion, we interpret these numbers in the context of the expected background for the experiment.« less

Formation of methyl formate in comets by irradiation of methanol-bearing ices

NASA Astrophysics Data System (ADS)

Modica, P.; Palumbo, M. E.; Strazzulla, G.

2012-12-01

Methyl formate is a complex organic molecule considered potentially relevant as precursor of biologically active molecules. It has been observed in several astrophysical environments, such as hot cores, hot corinos, and comets. The processes that drive the formation of molecules in cometary ices are poorly understood. In particular it is not yet clear if molecules are directly accreted from the pre-solar nebula to form comets or are formed after accretion. The present work analyzes the possible role of cosmic ion irradiation and radioactive decay in methyl formate formation in methanol-bearing ices. The results indicate that cosmic ion irradiation can account for about 12% of the methyl formate observed in comet Hale-Bopp, while radioactive decay can account for about 6% of this amount. The need of new data coming from earth based and space observational projects as well as from laboratory experiments is outlined.

Solar Neutrinos

DOE R&D Accomplishments Database

Davis, R. Jr.; Harmer, D. S.

1964-12-01

The prospect of studying the solar energy generation process directly by observing the solar neutrino radiation has been discussed for many years. The main difficulty with this approach is that the sun emits predominantly low energy neutrinos, and detectors for observing low fluxes of low energy neutrinos have not been developed. However, experimental techniques have been developed for observing neutrinos, and one can foresee that in the near future these techniques will be improved sufficiently in sensitivity to observe solar neutrinos. At the present several experiments are being designed and hopefully will be operating in the next year or so. We will discuss an experiment based upon a neutrino capture reaction that is the inverse of the electron-capture radioactive decay of argon-37. The method depends upon exposing a large volume of a chlorine compound, removing the radioactive argon-37 and observing the characteristic decay in a small low-level counter.

Carbon-14 decay as a source of non-canonical bases in DNA.

PubMed

Sassi, Michel; Carter, Damien J; Uberuaga, Blas P; Stanek, Chris R; Marks, Nigel A

2014-01-01

Significant experimental effort has been applied to study radioactive beta-decay in biological systems. Atomic-scale knowledge of this transmutation process is lacking due to the absence of computer simulations. Carbon-14 is an important beta-emitter, being ubiquitous in the environment and an intrinsic part of the genetic code. Over a lifetime, around 50 billion (14)C decays occur within human DNA. We apply ab initio molecular dynamics to quantify (14)C-induced bond rupture in a variety of organic molecules, including DNA base pairs. We show that double bonds and ring structures confer radiation resistance. These features, present in the canonical bases of the DNA, enhance their resistance to (14)C-induced bond-breaking. In contrast, the sugar group of the DNA and RNA backbone is vulnerable to single-strand breaking. We also show that Carbon-14 decay provides a mechanism for creating mutagenic wobble-type mispairs. The observation that DNA has a resistance to natural radioactivity has not previously been recognized. We show that (14)C decay can be a source for generating non-canonical bases. Our findings raise questions such as how the genetic apparatus deals with the appearance of an extra nitrogen in the canonical bases. It is not obvious whether or not the DNA repair mechanism detects this modification nor how DNA replication is affected by a non-canonical nucleobase. Accordingly, (14)C may prove to be a source of genetic alteration that is impossible to avoid due to the universal presence of radiocarbon in the environment. © 2013.

Update of the α - n Yields for Reactor Fuel Materials for the Interest of Nuclear Safeguards

NASA Astrophysics Data System (ADS)

Simakov, S. P.; van den Berg, Q. Y.

2017-01-01

The neutron yields caused by spontaneous α-decay of actinides and subsequent (α,xn) reactions were re-evaluated for the reactor fuel materials UO2, UF6, PuO2 and PuF4. For this purpose, the most recent reference data for decay parameters, α-particle stopping powers and (α,xn) cross sections were collected, analysed and used in calculations. The input data and elaborated code were validated against available thick target neutron yields in pure and compound materials measured at accelerators or with radioactive sources. This paper provides the specific neutron yields and their uncertainties resultant from α-decay of actinides 241Am, 249Bk, 252Cf, 242,244Cm, 237Np, 238-242Pu, 232Th and 232-236,238U in oxide and fluoride compounds. The obtained results are an update of previous reference tables issued by the Los Alamos National Laboratory in 1991 which were used for the safeguarding of radioactive materials by passive non-destructive techniques. The comparison of the updated values with previous ones shows an agreement within one estimated uncertainty (≈ 10%) for oxides, and deviations of up to 50% for fluorides.

BLT-EC (Breach, Leach and Transport-Equilibrium Chemistry) data input guide. A computer model for simulating release and coupled geochemical transport of contaminants from a subsurface disposal facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacKinnon, R.J.; Sullivan, T.M.; Kinsey, R.R.

1997-05-01

The BLT-EC computer code has been developed, implemented, and tested. BLT-EC is a two-dimensional finite element computer code capable of simulating the time-dependent release and reactive transport of aqueous phase species in a subsurface soil system. BLT-EC contains models to simulate the processes (container degradation, waste-form performance, transport, chemical reactions, and radioactive production and decay) most relevant to estimating the release and transport of contaminants from a subsurface disposal system. Water flow is provided through tabular input or auxiliary files. Container degradation considers localized failure due to pitting corrosion and general failure due to uniform surface degradation processes. Waste-form performancemore » considers release to be limited by one of four mechanisms: rinse with partitioning, diffusion, uniform surface degradation, and solubility. Transport considers the processes of advection, dispersion, diffusion, chemical reaction, radioactive production and decay, and sources (waste form releases). Chemical reactions accounted for include complexation, sorption, dissolution-precipitation, oxidation-reduction, and ion exchange. Radioactive production and decay in the waste form is simulated. To improve the usefulness of BLT-EC, a pre-processor, ECIN, which assists in the creation of chemistry input files, and a post-processor, BLTPLOT, which provides a visual display of the data have been developed. BLT-EC also includes an extensive database of thermodynamic data that is also accessible to ECIN. This document reviews the models implemented in BLT-EC and serves as a guide to creating input files and applying BLT-EC.« less

Paul Trapping of Radioactive {sup 6}He{sup +} Ions and Direct Observation of Their {beta} Decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flechard, X.; Lienard, E.; Mery, A.

2008-11-21

We demonstrate that abundant quantities of short-lived {beta} unstable ions can be trapped in a novel transparent Paul trap and that their decay products can directly be detected in coincidence. Low energy {sup 6}He{sup +} (807 ms half-life) ions were extracted from the SPIRAL source at GANIL, then decelerated, cooled, and bunched by means of the buffer gas cooling technique. More than 10{sup 8} ions have been stored over a measuring period of six days, and about 10{sup 5} decay coincidences between the beta particles and the {sup 6}Li{sup ++} recoiling ions have been recorded. The technique can be extendedmore » to other short-lived species, opening new possibilities for trap assisted decay experiments.« less

The Exchange.

ERIC Educational Resources Information Center

Blain, Mary P., Ed.; Pintavalle, Steven J., Ed.

1985-01-01

Presents 10 activities in biology, chemistry, physical science, and general science. Activities focus on: alfalfa sprouts; soap test; density; skating on cold ice; Kirlian photography; titration analysis (with program listing); radioactive decay; and others. Each activity includes suggested grade level(s) and procedures. (DH)

Physics Notes.

ERIC Educational Resources Information Center

School Science Review, 1982

1982-01-01

Demonstrations, procedures, games, teaching suggestions and information on a variety of physics topics are presented, including hydraulic rams, units and formulae, static electric motors, a computer graphics program, diffraction, adaptation of a basic meter, photoelasticity, photo-diodes, radioactive decay, and analog-digital conversions. (DC)

Recent advances in β-decay spectroscopy at CARIBU

NASA Astrophysics Data System (ADS)

Mitchell, A. J.; Copp, P.; Savard, G.; Lister, C. J.; Lane, G. J.; Carpenter, M. P.; Clark, J. A.; Zhu, S.; Ayangeakaa, A. D.; Bottoni, S.; Brown, T. B.; Chowdhury, P.; Chillery, T. W.; David, H. M.; Hartley, D. J.; Heckmaier, E.; Janssens, R. V. F.; Kolos, K.; Kondev, F. G.; Lauritsen, T.; McCutchan, E. A.; Norman, E. B.; Padgett, S.; Scielzo, N. D.; Seweryniak, D.; Smith, M. L.; Wilson, G. L.

2016-09-01

β-decay spectroscopy of nuclei far from stability can provide powerful insight into a broad variety of topics in nuclear science, ranging from exotic nuclear structure phenomena, stellar nucleosynthesis processes, and applied topics such as quantifying "decay heat" discrepancies for advanced nuclear fuel cycles. Neutronrich nuclei approaching the drip-line are difficult to access experimentally, leaving many key examples largely under studied. The CARIBU radioactive beam facility at Argonne National Laboratory exploits spontaneous fission of 252Cf in production of such beams. The X-Array and SATURN decay station have been commissioned to perform detailed decay spectroscopy of low-energy CARIBU beams. An extended science campaign was started during 2015; with projects investigating nuclear shape changes, collective octupole vibrations, β-delayed neutron emission, and decay-scheme properties which could explain the reactor antineutrino puzzle. In this article we review the current status of the setup, update on the first results and recent hardware upgrades, and look forward to future possibilities.

Comparison of Cf-252 thin-film sources prepared by evaporation or self-transfer

DOE PAGES

Algutifan, Noor J.; Sherman, Steven R.; Alexander, Charles W.

2014-11-29

Californium-252 (Z = 98) is valued as a potent neutron source due to its spontaneous fission decay path. Thin film sources containing Cf-252 were prepared by two techniques: evaporation and self-transfer. The sources were analyzed by alpha and gamma spectroscopy. Results indicate that self-transfer sources exhibit less alpha energy straggling and energy loss than evaporative sources. Fission fragments may also self-transfer, and sources made by self-transfer may need some decay time to reach radioactive equilibrium.

The Majorana Project

ScienceCinema

Orrell, John; Hoppe, Eric

2018-01-26

Working as part of a collaborative team, PNNL is bringing its signature capability in ultra-low-level detection to help search for a rare form of radioactive decay-never before detected-called "neutrinoless double beta decay" in germanium. If observed, it would demonstrate neutrinos are Majorana-type particles. This discovery would show neutrinos are unique among fundamental particles, having a property whereby the matter and anti-matter version of this particle are indistinguishable. Physicist John L. Orrell explains how they rely on the Shallow Underground Laboratory to conduct the research.

Automated QA/QC Check for Beta-Gamma Coincidence Detector

DTIC Science & Technology

2007-09-01

of the ARSA, 222Rn gas can be introduced into the gas cell, along with the radioactive xenon isotopes. While this radon decays via alpha decay and...Explosion Monitoring Technologies 741 Figure 2. γ-singles spectrum from a 222Rn spike. The peaks are primarily from the radon daughter 214Pb with...National Laboratory (PNNL), can collect and detect several radioxenon isotopes. The ARSA is very sensitive to 133Xe, 131mXe, 133mXe, and 135Xe due to the

Background canceling surface alpha detector

DOEpatents

MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

1996-06-11

A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

Background canceling surface alpha detector

DOEpatents

MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

1996-01-01

A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

IUPAC Periodic Table of Isotopes for the Educational Community

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holden N. E.; Holden,N.E.; Coplen,T.B.

2012-07-15

John Dalton first proposed the concept of atomic weights of the elements in the first decade of the nineteenth century. These atomic weights of the chemical elements were thought of as constants of nature, similar to the speed of light. Dmitri Mendeleev arranged the atomic weights of the elements in ascending order of value and used the systematic variation of their chemical properties to produce his Periodic Table of the Elements in 1869. Measurement of atomic weight values became an important chemical activity for a century and a half. Theodore Richards received a Noble Prize for his work in thismore » area. In 1913, Fredrick Soddy found a species of radium, which had an atomic weight value of 228, compared to the familiar radium gas value of 226. Soddy coined the term 'isotope' (Greek for 'in the same place') to account for this second atomic weight value in the radium position of the Periodic Table. Both of these isotopes of radium are radioactive. Radioactive isotopes are energetically unstable and will decay (disintegrate) over time. The time it takes for one half of a sample of a given radioactive isotope to decay is the half-life of that isotope. In addition to having different atomic weight values, radium-226 and radium-228 also have different half-life values. Around the same time as Soddy's work, J.J. Thomson (discoverer of the electron) identified two stable (non-radioactive) isotopes of the same element, neon. Over the next 40 years, the majority of the known chemical elements were found to have two or more stable (or long-lived radioactive isotopes that contribute significantly to the determination of the atomic weights of the elements).« less

Review of Monte Carlo simulations for backgrounds from radioactivity

NASA Astrophysics Data System (ADS)

Selvi, Marco

2013-08-01

For all experiments dealing with the rare event searches (neutrino, dark matter, neutrino-less double-beta decay), the reduction of the radioactive background is one of the most important and difficult tasks. There are basically two types of background, electron recoils and nuclear recoils. The electron recoil background is mostly from the gamma rays through the radioactive decay. The nuclear recoil background is from neutrons from spontaneous fission, (α, n) reactions and muoninduced interactions (spallations, photo-nuclear and hadronic interaction). The external gammas and neutrons from the muons and laboratory environment, can be reduced by operating the detector at deep underground laboratories and by placing active or passive shield materials around the detector. The radioactivity of the detector materials also contributes to the background; in order to reduce it a careful screening campaign is mandatory to select highly radio-pure materials. In this review I present the status of current Monte Carlo simulations aimed to estimate and reproduce the background induced by gamma and neutron radioactivity of the materials and the shield of rare event search experiment. For the electromagnetic background a good level of agreement between the data and the MC simulation has been reached by the XENON100 and EDELWEISS experiments, using the GEANT4 toolkit. For the neutron background, a comparison between the yield of neutrons from spontaneous fission and (α, n) obtained with two dedicated softwares, SOURCES-4A and the one developed by Mei-Zhang-Hime, show a good overall agreement, with total yields within a factor 2 difference. The energy spectra from SOURCES-4A are in general smoother, while those from MZH presents sharp peaks. The neutron propagation through various materials has been studied with two MC codes, GEANT4 and MCNPX, showing a reasonably good agreement, inside 50% discrepancy.

Localized internal radiotherapy with 90Y particles embedded in a new thermosetting alginate gel: a feasibility study in pigs.

PubMed

Holte, Oyvind; Skretting, Arne; Bach-Gansmo, Tore; Hol, Per Kristian; Johnsrud, Kjersti; Tønnesen, Hanne Hjorth; Karlsen, Jan

2006-02-01

Internal radiotherapy requires the localization of the radionuclide to the site of action. A new injectable alginate gel formulation intended to undergo immediate gelation in tissues and capable of encapsulating radioactive particles containing 90Y was investigated. The formulation was injected intramuscularly, into the bone marrow compartment of the femur and intravenously, respectively, in pigs. The distribution of radioactivity in various tissues was determined. Following intramuscular injection, more than 90% of the radioactivity was found at the site of injection. Following injection into bone marrow, 30-40% of the radioactivity was retained at the site of injection, but a considerable amount of radioactivity was also detected in the lungs (35-45%) and the liver (5-18%). Following intravenous injection, 80-90% of the radioactivity was found in the lungs. The present formulation appears suitable for localized radiotherapy in organs and tissues having low perfusion.

Hydrologic conditions at the Idaho National Engineering Laboratory, Idaho, emphasis; 1974-1978

USGS Publications Warehouse

Barraclough, Jack T.; Lewis, Barney D.; Jensen, Rodger G.

1981-01-01

Aqueous chemical and radioactive wastes have been discharged to shallow ponds and to shallow or deep wells on the Idaho National Engineering Laboratory (INEL) since 1952 and has affected the quality of the ground water in the underlying Snake River Plain aquifer. Ongoing studies conducted from 1974 through 1978 have shown the perpetuation of a perched ground-water zone in the basalt underlying the waste disposal ponds at the INEL 's Test Reactor Area and of several waste plumes in the regional aquifer created by deep well disposal at the Idaho Chemical Processing Plant (ICPP). The perched zone contains tritium, chromium-51, cobalt-60, strontium-90, and several nonradioactive chemicals. Tritium has formed the largest waste plume south of the ICPP, and accounts for 95 percent of the total radioacticity disposed of through the ICPP disposal well. Waste plumes with similar configurations and flowpaths contain sodium, chloride, and nitrate. Strontium-90, iodine-129, and cesium-137 are also discharged through the well but they are sorbed from solution as they move through the aquifer or are discharged in very small quantities. Strontium-90 and iodine-129 have formed small waste plumes and cesium-137 is not detectable in ground-water samples. Radionuclide plume size and concentrations therein are controlled by aquifer flow conditions, the quantity discharged, radioactive decay, sorption, dilution by dispersion, and perhaps other chemical reactions. Chemical wastes are subject to the same processes except for radioactive decay. (USGS)

Computers in the General Physics Laboratory.

ERIC Educational Resources Information Center

Preston, Daryl W.; Good, R. H.

1996-01-01

Provides ideas and outcomes for nine computer laboratory experiments using a commercial eight-bit analog to digital (ADC) interface. Experiments cover statistics; rotation; harmonic motion; voltage, current, and resistance; ADC conversions; temperature measurement; single slit diffraction; and radioactive decay. Includes necessary schematics. (MVL)

Computer Series, 13: Bits and Pieces, 11.

ERIC Educational Resources Information Center

Moore, John W., Ed.

1982-01-01

Describes computer programs (with ordering information) on various topics including, among others, modeling of thermodynamics and economics of solar energy, radioactive decay simulation, stoichiometry drill/tutorial (in Spanish), computer-generated safety quiz, medical chemistry computer game, medical biochemistry question bank, generation of…

Tailpulse signal generator

DOEpatents

Baker, John [Walnut Creek, CA; Archer, Daniel E [Knoxville, TN; Luke, Stanley John [Pleasanton, CA; Decman, Daniel J [Livermore, CA; White, Gregory K [Livermore, CA

2009-06-23

A tailpulse signal generating/simulating apparatus, system, and method designed to produce electronic pulses which simulate tailpulses produced by a gamma radiation detector, including the pileup effect caused by the characteristic exponential decay of the detector pulses, and the random Poisson distribution pulse timing for radioactive materials. A digital signal process (DSP) is programmed and configured to produce digital values corresponding to pseudo-randomly selected pulse amplitudes and pseudo-randomly selected Poisson timing intervals of the tailpulses. Pulse amplitude values are exponentially decayed while outputting the digital value to a digital to analog converter (DAC). And pulse amplitudes of new pulses are added to decaying pulses to simulate the pileup effect for enhanced realism in the simulation.

The EXPERT project: part of the Super-FRS Experiment Collaboration

NASA Astrophysics Data System (ADS)

Chudoba, V.; "EXPERT project, β-Decay Studies of r-Process Nuclei Using the Advanced Implantation Detector Array (AIDA)

NASA Astrophysics Data System (ADS)

Griffin, C. J.; Davinson, T.; Estrade, A.; Braga, D.; Burrows, I.; Coleman-Smith, P. J.; Grahn, T.; Grant, A.; Harkness-Brennan, L. J.; Kiss, G.; Kogimtzis, M.; Lazarus, I. H.; Letts, S. C.; Liu, Z.; Lorusso, G.; Matsui, K.; Nishimura, S.; Page, R. D.; Prydderch, M.; Phong, V. H.; Pucknell, V. F. E.; Rinta-Antila, S.; Roberts, O. J.; Seddon, D. A.; Simpson, J.; Thomas, S. L.; Woods, P. J.

Thought to produce around half of all isotopes heavier than iron, the r-process is a key mechanism for nucleosynthesis. However, a complete description of the r-process is still lacking and many unknowns remain. Experimental determination of β-decay half-lives and β-delayed neutron emission probabilities along the r-process path would help to facilitate a greater understanding of this process. The Advanced Implantation Detector Array (AIDA) represents the latest generation of silicon implantation detectors for β-decay studies with fast radioactive ion beams. Preliminary results from commissioning experiments demonstrate successful operation of AIDA and analysis of the data obtained during the first official AIDA experiments is now under-way.

Radiation and Thermal Ageing of Nuclear Waste Glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, William J

2014-01-01

The radioactive decay of fission products and actinides incorporated into nuclear waste glass leads to self-heating and self-radiation effects that may affect the stability, structure and performance of the glass in a closed system. Short-lived fission products cause significant self-heating for the first 600 years. Alpha decay of the actinides leads to self-radiation damage that can be significant after a few hundred years, and over the long time periods of geologic disposal, the accumulation of helium and radiation damage from alpha decay may lead to swelling, microstructural evolution and changes in mechanical properties. Four decades of research on the behaviormore » of nuclear waste glass are reviewed.« less

Differences in crystalline cellulose modification due to degradation by brown and white rot fungi.

PubMed

Hastrup, Anne Christine Steenkjær; Howell, Caitlin; Larsen, Flemming Hofmann; Sathitsuksanoh, Noppadon; Goodell, Barry; Jellison, Jody

2012-10-01

Wood-decaying basidiomycetes are some of the most effective bioconverters of lignocellulose in nature, however the way they alter wood crystalline cellulose on a molecular level is still not well understood. To address this, we examined and compared changes in wood undergoing decay by two species of brown rot fungi, Gloeophyllum trabeum and Meruliporia incrassata, and two species of white rot fungi, Irpex lacteus and Pycnoporus sanguineus, using X-ray diffraction (XRD) and (13)C solid-state nuclear magnetic resonance (NMR) spectroscopy. The overall percent crystallinity in wood undergoing decay by M. incrassata, G. trabeum, and I. lacteus appeared to decrease according to the stage of decay, while in wood decayed by P. sanguineus the crystallinity was found to increase during some stages of degradation. This result is suggested to be potentially due to the different decay strategies employed by these fungi. The average spacing between the 200 cellulose crystal planes was significantly decreased in wood degraded by brown rot, whereas changes observed in wood degraded by the two white rot fungi examined varied according to the selectivity for lignin. The conclusions were supported by a quantitative analysis of the structural components in the wood before and during decay confirming the distinct differences observed for brown and white rot fungi. The results from this study were consistent with differences in degradation methods previously reported among fungal species, specifically more non-enzymatic degradation in brown rot versus more enzymatic degradation in white rot. Copyright © 2012 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Impact of prostate edema on cell survival and tumor control after permanent interstitial brachytherapy for early stage prostate cancers

PubMed Central

Chen, Zhe (Jay); Roberts, Kenneth; Decker, Roy; Pathare, Pradip; Rockwell, Sara; Nath, Ravinder

2011-01-01

Previous studies have shown that the procedure-induced prostate edema during permanent interstitial brachytherapy (PIB) can cause significant variations in the dose delivered to the prostate gland. Because the clinical impact of edema-induced dose variations depends strongly on the magnitude of the edema, the temporal pattern of its resolution and its interplay with the decay of radioactivity and the underlying biological processes of tumor cells (such as tumor potential doubling time), we investigated the impact of edema-induced dose variations on the tumor cell survival and tumor control probability after PIB with the 131Cs, 125I and 103Pd sources used in current clinical practice. The exponential edema resolution model reported by Waterman et al. (Int. J. Radiat. Oncol. Biol. Phys. 41, 1069–1077–1998) was used to characterize the edema evolutions observed previously during clinical PIB for prostate cancer. The concept of biologically effective dose (BED), taking into account tumor cell proliferation and sublethal damage repair during dose delivery, was used to characterize the effects of prostate edema on cell survival and tumor control probability. Our calculation indicated that prostate edema, if not taken into account appropriately, can increase the cell survival and decrease the probability of local control of PIB. The edema-induced increase in cell survival increased with increasing edema severity, decreasing half-life for radioactive decay and decreasing energy of the photons energy emitted by the source. At the doses currently prescribed for PIB and for prostate cancer cells characterized by nominal radiobiology parameters recommended by AAPM TG-137, PIB using 125I sources was less affected by edema than PIB using 131Cs or 103Pd sources due to the long radioactive decay half-life of 125I. The effect of edema on PIB using 131Cs or 103Pd was similar. The effect of edema on 103Pd PIB was slightly greater, even though the decay half-life of 103Pd (17 days) is longer than that of 131Cs (9.7 days), because the advantage of the longer 103Pd decay half-life was negated by the lower effective energy of the photons it emits (~21 keV compared to ~30.4 keV for 131Cs). In addition, the impact of edema could be reduced or enhanced by differences in the tumor characteristics (e.g. potential tumor doubling time or the α/β ratio), and the effect of these factors varied for the different radioactive sources. There is a clear need to consider the effects of prostate edema during the planning and evaluation of permanent interstitial brachytherapy treatments for prostate cancer. PMID:21772076

The impact of prostate edema on cell survival and tumor control after permanent interstitial brachytherapy for early stage prostate cancers

NASA Astrophysics Data System (ADS)

(Jay Chen, Zhe; Roberts, Kenneth; Decker, Roy; Pathare, Pradip; Rockwell, Sara; Nath, Ravinder

2011-08-01

Previous studies have shown that procedure-induced prostate edema during permanent interstitial brachytherapy (PIB) can cause significant variations in the dose delivered to the prostate gland. Because the clinical impact of edema-induced dose variations strongly depends on the magnitude of the edema, the temporal pattern of its resolution and its interplay with the decay of radioactivity and the underlying biological processes of tumor cells (such as tumor potential doubling time), we investigated the impact of edema-induced dose variations on the tumor cell survival and tumor control probability after PIB with the 131Cs, 125I and 103Pd sources used in current clinical practice. The exponential edema resolution model reported by Waterman et al (1998 Int. J. Radiat. Oncol. Biol. Phys. 41 1069-77) was used to characterize the edema evolutions previously observed during clinical PIB for prostate cancer. The concept of biologically effective dose, taking into account tumor cell proliferation and sublethal damage repair during dose delivery, was used to characterize the effects of prostate edema on cell survival and tumor control probability. Our calculation indicated that prostate edema, if not appropriately taken into account, can increase the cell survival and decrease the probability of local control of PIB. The magnitude of an edema-induced increase in cell survival increased with increasing edema severity, decreasing half-life of radioactive decay and decreasing photon energy emitted by the source. At the doses currently prescribed for PIB and for prostate cancer cells characterized by nominal radiobiology parameters recommended by AAPM TG-137, PIB using 125I sources was less affected by edema than PIB using 131Cs or 103Pd sources due to the long radioactive decay half-life of 125I. The effect of edema on PIB using 131Cs or 103Pd was similar. The effect of edema on 103Pd PIB was slightly greater, even though the decay half-life of 103Pd (17 days) is longer than that of 131Cs (9.7 days), because the advantage of the longer 103Pd decay half-life was negated by the lower effective energy of the photons it emits (~21 keV compared to ~30.4 keV for 131Cs). In addition, the impact of edema could be reduced or enhanced by differences in the tumor characteristics (e.g. potential tumor doubling time or the α/β ratio), and the effect of these factors varied for the different radioactive sources. There is a clear need to consider the effects of prostate edema during the planning and evaluation of permanent interstitial brachytherapy treatments for prostate cancer.

Neutronics Design of a Thorium-Fueled Fission Blanket for LIFE (Laser Inertial Fusion-based Energy)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powers, J; Abbott, R; Fratoni, M

The Laser Inertial Fusion-based Energy (LIFE) project at LLNL includes development of hybrid fusion-fission systems for energy generation. These hybrid LIFE engines use high-energy neutrons from laser-based inertial confinement fusion to drive a subcritical blanket of fission fuel that surrounds the fusion chamber. The fission blanket contains TRISO fuel particles packed into pebbles in a flowing bed geometry cooled by a molten salt (flibe). LIFE engines using a thorium fuel cycle provide potential improvements in overall fuel cycle performance and resource utilization compared to using depleted uranium (DU) and may minimize waste repository and proliferation concerns. A preliminary engine designmore » with an initial loading of 40 metric tons of thorium can maintain a power level of 2000 MW{sub th} for about 55 years, at which point the fuel reaches an average burnup level of about 75% FIMA. Acceptable performance was achieved without using any zero-flux environment 'cooling periods' to allow {sup 233}Pa to decay to {sup 233}U; thorium undergoes constant irradiation in this LIFE engine design to minimize proliferation risks and fuel inventory. Vast reductions in end-of-life (EOL) transuranic (TRU) inventories compared to those produced by a similar uranium system suggest reduced proliferation risks. Decay heat generation in discharge fuel appears lower for a thorium LIFE engine than a DU engine but differences in radioactive ingestion hazard are less conclusive. Future efforts on development of thorium-fueled LIFE fission blankets engine development will include design optimization, fuel performance analysis work, and further waste disposal and nonproliferation analyses.« less

Neutron induced radio-isotopes and background for Ge double beta decay experiments

NASA Astrophysics Data System (ADS)

Chu, Pinghan; Majorana Collaboration

2015-10-01

Environmental neutrons, mostly produced by muons in the cosmic rays, might contribute backgrounds to the search for neutrinoless double beta decays. These neutrons can interact with materials and generate radio-isotopes, which can decay and produce radioactive backgrounds. Some of these neutron-induced isotopes have a signature of a time-delayed coincidence, allowing us to study these infrequent events. For example, such isotopes can decay by beta decay to metastable states and then decay by gamma decay to the ground state. Considering the time-delayed coincidence of these two processes, we can determine candidates for these neutron-induced isotopes in the data and estimate the flux of neutrons in the deep underground environment. In this report, we will list possible neutron-induced isotopes and the methodology to detect them, especially those that can affect the search for neutrinoless double beta decays in 76Ge. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

Radioisotope Dating with Accelerators.

ERIC Educational Resources Information Center

Muller, Richard A.

1979-01-01

Explains a new method of detecting radioactive isotopes by counting their accelerated ions rather than the atoms that decay during the counting period. This method increases the sensitivity by several orders of magnitude, and allows one to find the ages of much older and smaller samples. (GA)

The Analog Computer as a Teaching Tool in Physics

ERIC Educational Resources Information Center

Wylen, H. E.; Schwarz, W. M.

1973-01-01

Discusses use of two EAI semi-expanded TR-20 units to display solutions to differential equations for harmonic oscillators, quantum-mechanical particles, trajectories, radioactive decay series, and hysteresis curves. Suggests practical applications for both undergraduate physics laboratories and classroom demonstrations. (CC)

Activation and Environmental Aspects of In-Vacuum Vessel Components of CFETR

NASA Astrophysics Data System (ADS)

Zhang, Xiaokang; Liu, Songlin; Zhu, Qingjun; Gao, Fangfang; Li, Jia

2016-11-01

The water-cooled ceramic breeder (WCCB) blanket is one of the three candidates of China's Fusion Engineering Test Reactor (CFETR). The evaluation of the radioactivity and decay heat produced by neutrons for the in-vacuum vessel components is essential for the assessment of radioactive wastes and the safety of CFETR. The activation calculation of CFETR in-vacuum vessel components was carried out by using the Monte Carlo N-Particle Transport Code MCNP, IAEA Fusion Evaluated Nuclear Data Library FENDL2.1, and the nuclear inventory code FISPACT-2007 and corresponding EAF-2007 libraries. In these analyses, the three-dimensional (3-D) neutronics model was employed and the WCCB blanket, the divertor, and the shield were modeled in detail to provide the detailed spatial distribution of the neutron flux and energy spectra. Then the neutron flux, energy spectra and the materials specification were transferred to FISPACT for the activation calculation with an assumed irradiation scenario of CFETR. This paper presents the main results of the activation analysis to evaluate the radioactivity, the decay heat, the contact dose, and the waste classification of the radioactive materials. At the time of shutdown, the activity of the WCCB blanket is 1.88×1019 Bq and the specific activity, the decay heat and the contact dose rate are 1.7 × 1013 Bq/kg, 3.05 MW, and 2.0 × 103 Sv/h respectively. After cooling for 100 years, 79% (4166.4 tons) radioactive wastes produced from the blanket, divertor, high temperature shield (HTS) and low temperature shield (LTS) need near surface disposal, while 21% (1112.3 tons) need geological disposal. According to results of the contact dose rate, all the components of the blanket, divertor, HTS and LTS could potentially be recycled after shutdown by using advanced remote handling equipment. In addition, the selection of Eurofer97 or RAFM for the divertor is better than that of SS316 because SS316 makes the activity of the divertor-body keep at a relatively high level. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB108004, 2015BG108002, 2014GB122000, 2014GB119000), National Natural Science Foundation of China (No. 11175207)

Epidermal Growth Factor Receptor Overexpression as a Target for Auger Electron Radiotherapy of Breast Cancer

DTIC Science & Technology

1999-08-01

of 11ln-DTPA-hEGF in a compartment and a rate of elimination corresponding to the radioactive decay of the radionuclide, indium-1Il. = A0 /A, where I...on the growth rate of MDA-MB-468 or MCF-7 (1.5 X 104 EGFR/cell) cells was determined following treatment in vitro with 11 In-DTPA- hEGF, unlabelled...the nucleus within 24 hours. Chromatin contained 10% of internalized radioactivity. The growth rate of MDA-MB-468 cells was decreased 3-fold by

Radiological Air Sampling. Protocol Development for the Canadian Forces

DTIC Science & Technology

2003-03-01

samplers trap these airborne radon daughters . Because radon is ubiquitous, all air samplers will catch these radioactive radon daughters in the...environment is complicated because all air sampler filters are radioactive because of the radon daughters . ’Actually, D will often depend on the isotope that...simply as "radon". 2 DRDC Ottawa TM 2003-149 -28 - 22 R_ 211p0 214pb 3.8 d 3.0 m 27 m 214Bi 210TI Radon Daughters 20 m ŕ.3 m (Uranium Decay Chain

Radioactive waste disposal via electric propulsion

NASA Technical Reports Server (NTRS)

Burns, R. E.

1975-01-01

It is shown that space transportation is a feasible method of removal of radioactive wastes from the biosphere. The high decay heat of the isotopes powers a thermionic generator which provides electrical power for ion thrust engines. The massive shields (used to protect ground and flight personnel) are removed in orbit for subsequent reuse; the metallic fuel provides a shield for the avionics that guides the orbital stage to solar system escape. Performance calculations indicate that 4000 kg. of actinides may be removed per Shuttle flight. Subsidiary problems - such as cooling during ascent - are discussed.

Method for utilizing decay heat from radioactive nuclear wastes

DOEpatents

Busey, H.M.

1974-10-14

Management of radioactive heat-producing waste material while safely utilizing the heat thereof is accomplished by encapsulating the wastes after a cooling period, transporting the capsules to a facility including a plurality of vertically disposed storage tubes, lowering the capsules as they arrive at the facility into the storage tubes, cooling the storage tubes by circulating a gas thereover, employing the so heated gas to obtain an economically beneficial result, and continually adding waste capsules to the facility as they arrive thereat over a substantial period of time.

Search for the β decay of 96Zr

NASA Astrophysics Data System (ADS)

Finch, S. W.; Tornow, W.

2016-01-01

96Zr and 48Ca are unique among double-β decay candidate nuclides in that they may also undergo single-β decay. In the case of 96Zr, the single-β decay mode is dominated by the fourth-forbidden β decay with a 119 keV Q value. A search was conducted for the β decay of 96Zr by observing the decay of the daughter 96Nb nucleus. Two coaxial high-purity germanium detectors were used in coincidence to detect the γ-ray cascade produced by the daughter nucleus as it de-excited to the ground state. The experiment was carried out at the Kimballton Underground Research Facility and produced 685.7 days of data with a 17.91 g enriched sample. No counts were seen above background, producing a limit of T1/2 > 2.4 ×1019 year. This is the first experimental search that is able to discern between the β decay and the double-β decay to an excited state of 96Zr.

Polonium and lung cancer.

PubMed

Zagà, Vincenzo; Lygidakis, Charilaos; Chaouachi, Kamal; Gattavecchia, Enrico

2011-01-01

The alpha-radioactive polonium 210 (Po-210) is one of the most powerful carcinogenic agents of tobacco smoke and is responsible for the histotype shift of lung cancer from squamous cell type to adenocarcinoma. According to several studies, the principal source of Po-210 is the fertilizers used in tobacco plants, which are rich in polyphosphates containing radio (Ra-226) and its decay products, lead 210 (Pb-210) and Po-210. Tobacco leaves accumulate Pb-210 and Po-210 through their trichomes, and Pb-210 decays into Po-210 over time. With the combustion of the cigarette smoke becomes radioactive and Pb-210 and Po-210 reach the bronchopulmonary apparatus, especially in bifurcations of segmental bronchi. In this place, combined with other agents, it will manifest its carcinogenic activity, especially in patients with compromised mucous-ciliary clearance. Various studies have confirmed that the radiological risk from Po-210 in a smoker of 20 cigarettes per day for a year is equivalent to the one deriving from 300 chest X-rays, with an autonomous oncogenic capability of 4 lung cancers per 10000 smokers. Po-210 can also be found in passive smoke, since part of Po-210 spreads in the surrounding environment during tobacco combustion. Tobacco manufacturers have been aware of the alpha-radioactivity presence in tobacco smoke since the sixties.

Polonium and Lung Cancer

PubMed Central

Zagà, Vincenzo; Lygidakis, Charilaos; Chaouachi, Kamal; Gattavecchia, Enrico

2011-01-01

The alpha-radioactive polonium 210 (Po-210) is one of the most powerful carcinogenic agents of tobacco smoke and is responsible for the histotype shift of lung cancer from squamous cell type to adenocarcinoma. According to several studies, the principal source of Po-210 is the fertilizers used in tobacco plants, which are rich in polyphosphates containing radio (Ra-226) and its decay products, lead 210 (Pb-210) and Po-210. Tobacco leaves accumulate Pb-210 and Po-210 through their trichomes, and Pb-210 decays into Po-210 over time. With the combustion of the cigarette smoke becomes radioactive and Pb-210 and Po-210 reach the bronchopulmonary apparatus, especially in bifurcations of segmental bronchi. In this place, combined with other agents, it will manifest its carcinogenic activity, especially in patients with compromised mucous-ciliary clearance. Various studies have confirmed that the radiological risk from Po-210 in a smoker of 20 cigarettes per day for a year is equivalent to the one deriving from 300 chest X-rays, with an autonomous oncogenic capability of 4 lung cancers per 10000 smokers. Po-210 can also be found in passive smoke, since part of Po-210 spreads in the surrounding environment during tobacco combustion. Tobacco manufacturers have been aware of the alpha-radioactivity presence in tobacco smoke since the sixties. PMID:21772848

Photoactivation of PBFA-2

NASA Astrophysics Data System (ADS)

Simmons, T. N.; Mashburn, J. B.

A 30 MV peak output voltage will be produced. A substantial portion of the output energy will be lost as free electrons which produce hard X-rays. Many X-rays will have energies within the photoneutron giant resonance. A PBFA-2 shot will produce about 5 x 10 E14 photoneutrons. These photoneutron reactions will induce radioactivity in and about PBFA-2. Activation structural components in the center section will be limited by substituting aluminum for stainless steel in regions of high X-ray intensity. Air will be activated above and below the center section after shots; however, X-ray shielding will limit initial concentrations to five times health guidelines. The short half-lives of air radioactivity will permit reentry following simple decay without ventilation. Some radioactive material will be eroded by arcing, but the resulting contamination whould be small. Miniscule concentrations of radioactivity will be produced in the water surrounding the center section.

Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident.

PubMed

Saito, Kimiaki; Tanihata, Isao; Fujiwara, Mamoru; Saito, Takashi; Shimoura, Susumu; Otsuka, Takaharu; Onda, Yuichi; Hoshi, Masaharu; Ikeuchi, Yoshihiro; Takahashi, Fumiaki; Kinouchi, Nobuyuki; Saegusa, Jun; Seki, Akiyuki; Takemiya, Hiroshi; Shibata, Tokushi

2015-01-01

Soil deposition density maps of gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident were constructed on the basis of results from large-scale soil sampling. In total 10,915 soil samples were collected at 2168 locations. Gamma rays emitted from the samples were measured by Ge detectors and analyzed using a reliable unified method. The determined radioactivity was corrected to that of June 14, 2011 by considering the intrinsic decay constant of each nuclide. Finally the deposition maps were created for (134)Cs, (137)Cs, (131)I, (129m)Te and (110m)Ag. The radioactivity ratio of (134)Cs-(137)Cs was almost constant at 0.91 regardless of the locations of soil sampling. The radioactivity ratios of (131)I and (129m)Te-(137)Cs were relatively high in the regions south of the Fukushima NPP site. Effective doses for 50 y after the accident were evaluated for external and inhalation exposures due to the observed radioactive nuclides. The radiation doses from radioactive cesium were found to be much higher than those from the other radioactive nuclides. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Nuclear Forensics and Radiochemistry: Reaction Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rundberg, Robert S.

In the intense neutron flux of a nuclear explosion the production of isotopes may occur through successive neutron induced reactions. The pathway to these isotopes illustrates both the complexity of the problem and the need for high quality nuclear data. The growth and decay of radioactive isotopes can follow a similarly complex network. The Bateman equation will be described and modified to apply to the transmutation of isotopes in a high flux reactor. A alternative model of growth and decay, the GD code, that can be applied to fission products will also be described.

Radiogenic nature of argon-40 in the oldest biotites of the Kola peninsula

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerling, E.K.; Gorokhovskii, B.M.

1986-07-01

It is shown by three graphical methods that ancient biotite aged 5.1.10/sup 9/ yr. and older does not contain excess /sup 40/Ar and that the whole /sup 40/Ar was formed via radioactive decay of /sup 40/K present in the minerals. It is suggested that due to variation in the force of gravitational interaction with the age of the universe, the K-decay of the /sup 40/K nucleus slowed down, which indeed is the cause of enhanced age of the Kola biotite.

High-precision half-life and branching-ratio measurements for superallowed Fermi β+ emitters at TRIUMF - ISAC

NASA Astrophysics Data System (ADS)

Laffoley, A. T.; Dunlop, R.; Finlay, P.; Grinyer, G. F.; Andreoiu, C.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Blank, B.; Bouzomita, H.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Demand, G.; Diaz Varela, A.; Djongolov, M.; Ettenauer, S.; Garnsworthy, A. B.; Garrett, P. E.; Giovinazzo, J.; Glister, J.; Green, K. L.; Hackman, G.; Hadinia, B.; Jamieson, D. S.; Ketelhut, S.; Leach, K. G.; Leslie, J. R.; Pearson, C. J.; Phillips, A. A.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Svensson, C. E.; Tardiff, E. R.; Thomas, J. C.; Towner, I. S.; Triambak, S.; Unsworth, C.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2014-03-01

A program of high-precision half-life and branching-ratio measurements for superallowed Fermi β emitters is being carried out at TRIUMF's Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. Recent half-life measurements for the superallowed decays of 14O, 18Ne, and 26Alm, as well as branching-ratio measurements for 26Alm and 74Rb are reported. These results provide demanding tests of the Standard Model and the theoretical isospin symmetry breaking (ISB) corrections in superallowed Fermi β decays.

Tests of a Fast Plastic Scintillator for High-Precision Half-Life Measurements

NASA Astrophysics Data System (ADS)

Laffoley, A. T.; Dunlop, R.; Finlay, P.; Leach, K. G.; Michetti-Wilson, J.; Rand, E. T.; Svensson, C. E.; Grinyer, G. F.; Thomas, J. C.; Ball, G.; Garnsworthy, A. B.; Hackman, G.; Orce, J. N.; Triambak, S.; Williams, S. J.; Andreoiu, C.; Cross, D.

2013-03-01

A fast plastic scintillator detector is evaluated for possible use in an ongoing program of high-precision half-life measurements of short lived β emitters. Using data taken at TRI-UMF's Isotope Separator and Accelerator Facility with a radioactive 26Na beam, a detailed investigation of potential systematic effects with this new detector setup is being performed. The technique will then be applied to other β-decay half-life measurements including the superallowed Fermi β emitters 10C, 14O, and T = 1/2 decay of 15O.

Two-neutron decay within RMF+BCS approach

NASA Astrophysics Data System (ADS)

Kumawat, M.; Singh, U. K.; Saxena, G.; Kaushik, M.; Jain, S. K.

2018-05-01

A theoretical global study has been done for identifying possible candidates of 2n-radioactivity for all even and odd nuclei under proton number Z ≤ 40 by employing Relativistic Mean-Filed plus BCS (RMF+BCS) approach. We investigate two-and one-neutron separation energy, deformation, pairing energy, wave-function, potential and other ground state properties for our study of even and odd Z nuclei to find candidates of 2n-decay within Z ≤ 40. These results are found in agreement of recent experiments and consistent with other parameters of RMF and other theories.

β -delayed neutron emission from 85Ga

NASA Astrophysics Data System (ADS)

Miernik, K.; Rykaczewski, K. P.; Grzywacz, R.; Gross, C. J.; Madurga, M.; Miller, D.; Stracener, D. W.; Batchelder, J. C.; Brewer, N. T.; Korgul, A.; Mazzocchi, C.; Mendez, A. J.; Liu, Y.; Paulauskas, S. V.; Winger, J. A.; Wolińska-Cichocka, M.; Zganjar, E. F.

2018-05-01

Decay of 85Ga was studied by means of β -neutron-γ spectroscopy. A pure beam of 85Ga was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and a high-resolution electromagnetic separator. The β -delayed neutron emission probability was measured for the first time, yielding 70(5)%. An upper limit of 0.1% for β -delayed two-neutron emission was also experimentally established for the first time. A detailed decay scheme including absolute γ -ray intensities was obtained. Results are compared with theoretical β -delayed emission models.

The Earth's Mantle.

ERIC Educational Resources Information Center

McKenzie, D. P.

1983-01-01

The nature and dynamics of the earth's mantle is discussed. Research indicates that the silicate mantle is heated by the decay of radioactive isotopes and that the heat energizes massive convention currents in the upper 700 kilometers of the ductile rock. These currents and their consequences are considered. (JN)

A Californium-252 Neutron Source for Student Use

ERIC Educational Resources Information Center

Bowen, H. J.

1975-01-01

Describes an undergraduate chemistry experiment which utilizes small samples of Californium 252 as a neutron source for the activation of 12 other elements. The students prepare decay curves of the radioactive isotopes and perform nondestructive activation analyses for gram amounts of some elements. (MLH)

Pulsational Pair-instability Model for Superluminous Supernova PTF12dam: Interaction and Radioactive Decay

NASA Astrophysics Data System (ADS)

Tolstov, Alexey; Nomoto, Ken'ichi; Blinnikov, Sergei; Sorokina, Elena; Quimby, Robert; Baklanov, Petr

2017-02-01

Being a superluminous supernova, PTF12dam can be explained by a 56Ni-powered model, a magnetar-powered model, or an interaction model. We propose that PTF12dam is a pulsational pair-instability supernova, where the outer envelope of a progenitor is ejected during the pulsations. Thus, it is powered by a double energy source: radioactive decay of 56Ni and a radiative shock in a dense circumstellar medium. To describe multicolor light curves and spectra, we use radiation-hydrodynamics calculations of the STELLA code. We found that light curves are well described in the model with 40 M⊙ ejecta and 20-40 M⊙ circumstellar medium. The ejected 56Ni mass is about 6 M⊙, which results from explosive nucleosynthesis with large explosion energy (2-3) × 1052 erg. In comparison with alternative scenarios of pair-instability supernova and magnetar-powered supernova, in the interaction model, all the observed main photometric characteristics are well reproduced: multicolor light curves, color temperatures, and photospheric velocities.

Two-photon decay of K-shell vacancies in silver atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mokler, P.H.; University of Giessen, Giessen; Schaeffer, H.W.

2004-09-01

The spectral distributions for the two-photon decay modes of singly K-shell ionized silver atoms are determined by x-ray-x-ray coincidence measurements. Ag K-shell vacancies were induced by nuclear electron capture decay of radioactive cadmium isotopes {sup 109}Cd and two-photon coincidences were taken back to back (180 deg.) and at a 90 deg. opening angle for the emission. Each of the two-photon transitions from the 2s, 3s, and 3d states exhibits unique angular and spectral distributions. The measurements agree nicely with relativistic self-consistent field calculations of Tong et al. Our results also confirm and extend the earlier experimental data of Ilakovac andmore » co-workers with improved accuracy.« less

Quality assurance of temporal variability of natural decay chain and neutron induced background for low-level NORM analysis

DOE PAGES

Yoho, Michael; Porterfield, Donivan R.; Landsberger, Sheldon

2015-09-22

In this study, twenty-one high purity germanium (HPGe) background spectra were collected over 2 years at Los Alamos National Laboratory. A quality assurance methodology was developed to monitor spectral background levels from thermal and fast neutron flux levels and naturally occurring radioactive material decay series radionuclides. 238U decay products above 222Rn demonstrated minimal temporal variability beyond that expected from counting statistics. 238U and 232Th progeny below Rn gas displayed at most twice the expected variability. Further, an analysis of the 139 keV 74Ge(n, γ) and 691 keV 72Ge(n, n') spectral features demonstrated temporal stability for both thermal and fastmore » neutron fluxes.« less

Internal γ Decay and the Superallowed Branching Ratio for the β+ Emitter Km38

NASA Astrophysics Data System (ADS)

Leach, K. G.; Svensson, C. E.; Ball, G. C.; Leslie, J. R.; Austin, R. A. E.; Bandyopadhyay, D.; Barton, C.; Bassiachvilli, E.; Ettenauer, S.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Melconian, D.; Morton, A. C.; Mythili, S.; Newman, O.; Pearson, C. J.; Pearson, M. R.; Phillips, A. A.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-05-01

The branching ratio for the superallowed β+ decay of Km38 was measured at TRIUMF’s ISAC radioactive ion beam facility. The M3 internal transition between the isomer and the ground state of Km38 was observed with a branching ratio of 330(43) ppm. A search for the nonanalogue β-decay branch to the first excited 0+ state in Ar38 was also performed and yielded an upper limit of ≤12ppm at 90% C.L. These measurements lead to a revised superallowed branching ratio for Km38 of 99.967(4)%, and increase the Km38 ft value by its entire quoted uncertainty to ft=3052.1(10)s. Implications for tests of the nuclear-structure dependent corrections in superallowed β decays and the extraction of the Cabibbo-Kobayashi-Maskawa matrix element Vud are discussed.

Correlation measurements in nuclear {beta}-decay using traps and polarized low energy beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naviliat-Cuncic, Oscar

2013-05-06

Precision measurements in nuclear {beta}-decay provide sensitive means to test discrete symmetries in the weak interaction and to determine some of the fundamental constants in semi-leptonic decays, like the coupling of the lightest quarks to charged weak bosons. The main motivation of such measurements is to find deviations from Standard Model predictions as possible indications of new physics. In this contribution I will focus on two topics related to precision measurements in nuclear {beta}-decay: i) the determination of the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix from nuclear mirror transitions and ii) the search for exotic scalar ormore » tensor contributions from {beta}{nu} angular correlations. The purpose is to underline the role being played by experimental techniques based on the confinement of radioactive species with atom and ion traps as well as the plans to use low energy polarized beams.« less

Simultaneous determination of radionuclides separable into natural decay series by use of time-interval analysis.

PubMed

Hashimoto, Tetsuo; Sanada, Yukihisa; Uezu, Yasuhiro

2004-05-01

A delayed coincidence method, time-interval analysis (TIA), has been applied to successive alpha- alpha decay events on the millisecond time-scale. Such decay events are part of the (220)Rn-->(216)Po ( T(1/2) 145 ms) (Th-series) and (219)Rn-->(215)Po ( T(1/2) 1.78 ms) (Ac-series). By using TIA in addition to measurement of (226)Ra (U-series) from alpha-spectrometry by liquid scintillation counting (LSC), two natural decay series could be identified and separated. The TIA detection efficiency was improved by using the pulse-shape discrimination technique (PSD) to reject beta-pulses, by solvent extraction of Ra combined with simple chemical separation, and by purging the scintillation solution with dry N(2) gas. The U- and Th-series together with the Ac-series were determined, respectively, from alpha spectra and TIA carried out immediately after Ra-extraction. Using the (221)Fr-->(217)At ( T(1/2) 32.3 ms) decay process as a tracer, overall yields were estimated from application of TIA to the (225)Ra (Np-decay series) at the time of maximum growth. The present method has proven useful for simultaneous determination of three radioactive decay series in environmental samples.

Tritium plume dynamics in the shallow unsaturated zone in an arid environment

USGS Publications Warehouse

Maples, S.R.; Andraski, Brian J.; Stonestrom, David A.; Cooper, C.A.; Pohll, G.; Michel, R.L.

2014-01-01

The spatiotemporal variability of a tritium plume in the shallow unsaturated zone and the mechanisms controlling its transport were evaluated during a 10-yr study. Plume movement was minimal and its mass declined by 68%. Upward-directed diffusive-vapor tritium fluxes and radioactive decay accounted for most of the observed plume-mass declines.Effective isolation of tritium (3H) and other contaminants at waste-burial facilities requires improved understanding of transport processes and pathways. Previous studies documented an anomalously widespread (i.e., theoretically unexpected) distribution of 3H (>400 m from burial trenches) in a dry, sub-root-zone gravelly layer (1–2-m depth) adjacent to a low-level radioactive waste (LLRW) burial facility in the Amargosa Desert, Nevada, that closed in 1992. The objectives of this study were to: (i) characterize long-term, spatiotemporal variability of 3H plumes; and (ii) quantify the processes controlling 3H behavior in the sub-root-zone gravelly layer beneath native vegetation adjacent to the facility. Geostatistical methods, spatial moment analyses, and mass flux calculations were applied to a spatiotemporally comprehensive, 10-yr data set (2001–2011). Results showed minimal bulk-plume advancement during the study period and limited Fickian spreading of mass. Observed spreading rates were generally consistent with theoretical vapor-phase dispersion. The plume mass diminished more rapidly than would be expected from radioactive decay alone, indicating net efflux from the plume. Estimates of upward 3H efflux via diffusive-vapor movement were >10× greater than by dispersive-vapor or total-liquid movement. Total vertical fluxes were >20× greater than lateral diffusive-vapor fluxes, highlighting the importance of upward migration toward the land surface. Mass-balance calculations showed that radioactive decay and upward diffusive-vapor fluxes contributed the majority of plume loss. Results indicate that plume losses substantially exceeded any continuing 3H contribution to the plume from the LLRW facility during 2001 to 2011 and suggest that the widespread 3H distribution resulted from transport before 2001.

Ionizing radiation-induced destruction of benzene and dienes in aqueous media.

PubMed

Al-Sheikhly, Mohamad; Poster, Dianne L; An, Jung-Chul; Neta, Pedatsur; Silverman, Joseph; Huie, Robert E

2006-05-01

Pulse radiolysis with spectrophotometric and conductometric detection was utilized to study the formation and reactions of radicals from benzene and dienes in aqueous solutions. The benzene OH adduct, *C6H6OH, reacts with O2 (k = 3 x 10(8) L mol(-1) s(-1)) in a reversible reaction. The peroxyl radical, HOC6H6O2*, undergoes O2*- elimination, bimolecular decay, and reaction with benzene to initiate a chain reaction, depending on the dose rate, benzene concentration, and pH. The occurrence of the chain reaction is demonstrated in low-dose-rate gamma radiolysis experiments where the consumption of O2 was monitored. 1,4-Cyclohexadiene, 1,4-hexadiene, and 1,4-pentadiene form OH-adducts and undergo H-abstraction by O*- radicals. The OH-adducts react with O2 to form peroxyl radicals. These peroxyl radicals, however, do not undergo unimolecular O2*- elimination but rather decay by second-order processes, which lead to subsequent steps of O2*- elimination.

Chemical Dosing and First-Order Kinetics

ERIC Educational Resources Information Center

Hladky, Paul W.

2011-01-01

College students encounter a variety of first-order phenomena in their mathematics and science courses. Introductory chemistry textbooks that discuss first-order processes, usually in conjunction with chemical kinetics or radioactive decay, stop at single, discrete dose events. Although single-dose situations are important, multiple-dose events,…

News

NASA Astrophysics Data System (ADS)

2008-07-01

Radioactivity: Olympic Games: dirty and decaying? Awards: SciCast rewards the best in scientific short films Conference: Teachers conference is big in Boston Workshop: Experts and teachers mingle in Mexico Awards: Olympiad holds lavish ceremony Cinema: Indiana Jones has a skull full of physics Conference: ESERA announces Turkish delight for 2009 Forthcoming Events

Role of higher-multipole deformations in exotic {sup 14}C cluster radioactivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawhney, Gudveen; Sharma, Manoj K.; Gupta, Raj K.

2011-06-15

We have studied nine cases of spontaneous emission of {sup 14}C clusters in the ground-state decays of the same number of parent nuclei from the trans-lead region, specifically from {sup 221}Fr to {sup 226}Th, using the preformed cluster model (PCM) of Gupta and collaborators, with choices of spherical, quadrupole deformation ({beta}{sub 2}) alone, and higher-multipole deformations ({beta}{sub 2}, {beta}{sub 3}, {beta}{sub 4}) with cold ''compact'' orientations {theta}{sup c} of decay products. The calculated {sup 14}C cluster decay half-life times are found to be in nice agreement with experimental data only for the case of higher-multipole deformations ({beta}{sub 2}-{beta}{sub 4}) andmore » {theta}{sup c} orientations of cold elongated configurations. In other words, compared to our earlier study of clusters heavier than {sup 14}C, where the inclusion of {beta}{sub 2} alone, with ''optimum'' orientations, was found to be enough to give the best comparison with data, here for {sup 14}C cluster decay the inclusion of higher-multipole deformations (up to hexadecapole), together with {theta}{sup c} orientations, is found to be essential on the basis of the PCM. Interestingly, whereas both the penetration probability and assault frequency work simply as scaling factors, the preformation probability is strongly influenced by the order of multipole deformations and orientations of nuclei. The possible role of Q value and angular-momentum effects are also considered in reference to {sup 14}C cluster radioactivity.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dobrescu, Bogdan A.

Color-singlet gauge bosons with renormalizable couplings to quarks but not to leptons must interact with additional fermions (''anomalons'') required to cancel the gauge anomalies. Analyzing the decays of such leptophobic bosons into anomalons, I show that they produce final states involving leptons at the LHC. Resonant production of a flavor-universal leptophobic Z' boson leads to cascade decays via anomalons, whose signatures include a leptonically decaying Z, missing energy and several jets. A Z' boson that couples to the right-handed quarks of the first and second generations undergoes cascade decays that violate lepton universality and include signals with two leptons andmore » jets, or with a Higgs boson, a lepton, a W and missing energy.« less

An overview of radioactive waste disposal procedures of a nuclear medicine department

PubMed Central

Ravichandran, R.; Binukumar, J. P.; Sreeram, Rajan; Arunkumar, L. S.

2011-01-01

Radioactive wastes from hospitals form one of the various types of urban wastes, which are managed in developed countries in a safe and organized way. In countries where growth of nuclear medicine services are envisaged, implementations of existing regulatory policies and guidelines in hospitals in terms of handling of radioactive materials used in the treatment of patients need a good model. To address this issue, a brief description of the methods is presented. A designed prototype waste storage trolley is found to be of great help in decaying the I-131 solid wastes from wards before releasing to waste treatment plant of the city. Two delay tanks with collection time of about 2 months and delay time of 2 months alternately result in 6 releases of urine toilet effluents to the sewage treatment plant (STP) of the hospital annually. Samples of effluents collected at releasing time documented radioactive releases of I-131 much below recommended levels of bi-monthly release. External counting of samples showed good statistical correlation with calculated values. An overview of safe procedures for radioactive waste disposal is presented. PMID:21731225

An overview of radioactive waste disposal procedures of a nuclear medicine department.

PubMed

Ravichandran, R; Binukumar, J P; Sreeram, Rajan; Arunkumar, L S

2011-04-01

Radioactive wastes from hospitals form one of the various types of urban wastes, which are managed in developed countries in a safe and organized way. In countries where growth of nuclear medicine services are envisaged, implementations of existing regulatory policies and guidelines in hospitals in terms of handling of radioactive materials used in the treatment of patients need a good model. To address this issue, a brief description of the methods is presented. A designed prototype waste storage trolley is found to be of great help in decaying the I-131 solid wastes from wards before releasing to waste treatment plant of the city. Two delay tanks with collection time of about 2 months and delay time of 2 months alternately result in 6 releases of urine toilet effluents to the sewage treatment plant (STP) of the hospital annually. Samples of effluents collected at releasing time documented radioactive releases of I-131 much below recommended levels of bi-monthly release. External counting of samples showed good statistical correlation with calculated values. An overview of safe procedures for radioactive waste disposal is presented.

Chem I Supplement: Nuclear Synthesis and Identification of New Elements.

ERIC Educational Resources Information Center

Seaborg, Glenn T.

1985-01-01

As background material for a paper on the transuranium elements (SE 537 837), this article reviews: (1) several descriptive terms; (2) nuclear reactions; (3) radioactive decay modes; (4) chemical background; and (5) experimental methods used in this field of research and more broadly in nuclear chemistry. (Author/JN)

Tritium trick

NASA Technical Reports Server (NTRS)

Green, W. V.; Zukas, E. G.; Eash, D. T.

1971-01-01

Large controlled amounts of helium in uniform concentration in thick samples can be obtained through the radioactive decay of dissolved tritium gas to He3. The term, tritium trick, applies to the case when helium, added by this method, is used to simulate (n,alpha) production of helium in simulated hard flux radiation damage studies.

Radiological Dispersion Devices and Basic Radiation Science

ERIC Educational Resources Information Center

Bevelacqua, Joseph John

2010-01-01

Introductory physics courses present the basic concepts of radioactivity and an overview of nuclear physics that emphasizes the basic decay relationship and the various types of emitted radiation. Although this presentation provides insight into radiological science, it often fails to interest students to explore these concepts in a more rigorous…

Towards a Conceptual Diagnostic Survey in Nuclear Physics

ERIC Educational Resources Information Center

Kohnle, Antje; Mclean, Stewart; Aliotta, Marialuisa

2011-01-01

Understanding students' prior beliefs in nuclear physics is a first step towards improving nuclear physics instruction. This paper describes the development of a diagnostic survey in nuclear physics covering the areas of radioactive decay, binding energy, properties of the nuclear force and nuclear reactions, that was administered to students at…

Recent Developments in Young-Earth Creationist Geology

ERIC Educational Resources Information Center

Heaton, Timothy H.

2009-01-01

Young-earth creationism has undergone a shift in emphasis toward building of historical models that incorporate Biblical and scientific evidence and the acceptance of scientific conclusions that were formerly rejected. The RATE Group admitted that massive amounts of radioactive decay occurred during earth history but proposed a period of…

Nuclear Data Sheets for A = 143

NASA Astrophysics Data System (ADS)

Browne, E.; Tuli, J. K.

2012-03-01

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reaction studies for all nuclei with mass number A = 143. The evaluation, which includes all data received by May 2011, supersedes the 2001 evaluation by J.K. Tuli, published in Nuclear Data Sheets94, 605 (2001).

Nuclear Data Sheets for A=143

DOE Office of Scientific and Technical Information (OSTI.GOV)

Browne E.; Tuli J.; Browne,E.

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reaction studies for all nuclei with mass number A = 143. The evaluation, which includes all data received by May 2011, supersedes the 2001 evaluation by J.K. Tuli, published in Nuclear Data Sheets94, 605 (2001).

Radioactive Decay: Audio Data Collection

ERIC Educational Resources Information Center

Struthers, Allan

2009-01-01

Many phenomena generate interesting audible time series. This data can be collected and processed using audio software. The free software package "Audacity" is used to demonstrate the process by recording, processing, and extracting click times from an inexpensive radiation detector. The high quality of the data is demonstrated with a simple…

Gamma-Ray Spectroscopy at TRIUMF-ISAC: the New Frontier of Radioactive Ion Beam Research

NASA Astrophysics Data System (ADS)

Ball, G. C.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Becker, J. A.; Bricault, P.; Brown, N.; Chan, S.; Churchman, R.; Colosimo, S.; Coombes, H.; Cross, D.; Demand, G.; Drake, T. E.; Dombsky, M.; Ettenauer, S.; Finlay, P.; Furse, D.; Garnsworthy, A.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hyland, B.; Hackman, G.; Kanungo, R.; Kulp, W. D.; Lassen, J.; Leach, K. G.; Leslie, J. R.; Mattoon, C.; Melconian, D.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Rand, E.; Sarazin, F.; Svensson, C. E.; Sumithrarachchi, S.; Schumaker, M. A.; Triambak, S.; Waddington, J. C.; Walker, P. M.; Williams, S. J.; Wood, J. L.; Wong, J.; Zganjar, E. F.

2009-03-01

High-resolution gamma-ray spectroscopy is essential to fully exploit the unique scientific opportunities at the next generation radioactive ion beam facilities such as the TRIUMF Isotope Separator and Accelerator (ISAC). At ISAC the 8π spectrometer and its associated auxiliary detectors is optimize for β-decay studies while TIGRESS an array of segmented clover HPGe detectors has been designed for studies with accelerated beams. This paper gives a brief overview of these facilities and also presents recent examples of the diverse experimental program carried out at the 8π spectrometer.

Nuclear science outreach program for high school girls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foster, D.E.; Stone, C.A.

1996-12-31

The authors have developed a 2-week summer school on nuclear science for high school girls. This summer school is an outgrowth of a recent American Nuclear Society high school teachers workshop held at San Jose State University. Young scientists are introduced to concepts in nuclear science through a combination of lectures, laboratory experiments, literature research, and visits to local national laboratories and nuclear facilities. Lectures cover a range of topics, including radioactivity and radioactive decay, statistics, fission and fusion, nuclear medicine, and food irradiation. A variety of applications of nuclear science concepts are also presented.

Neutron counter based on beryllium activation

NASA Astrophysics Data System (ADS)

Bienkowska, B.; Prokopowicz, R.; Scholz, M.; Kaczmarczyk, J.; Igielski, A.; Karpinski, L.; Paducha, M.; Pytel, K.

2014-08-01

The fusion reaction occurring in DD plasma is followed by emission of 2.45 MeV neutrons, which carry out information about fusion reaction rate and plasma parameters and properties as well. Neutron activation of beryllium has been chosen for detection of DD fusion neutrons. The cross-section for reaction 9Be(n, α)6He has a useful threshold near 1 MeV, which means that undesirable multiple-scattered neutrons do not undergo that reaction and therefore are not recorded. The product of the reaction, 6He, decays with half-life T1/2 = 0.807 s emitting β- particles which are easy to detect. Large area gas sealed proportional detector has been chosen as a counter of β-particles leaving activated beryllium plate. The plate with optimized dimensions adjoins the proportional counter entrance window. Such set-up is also equipped with appropriate electronic components and forms beryllium neutron activation counter. The neutron flux density on beryllium plate can be determined from the number of counts. The proper calibration procedure needs to be performed, therefore, to establish such relation. The measurements with the use of known β-source have been done. In order to determine the detector response function such experiment have been modeled by means of MCNP5-the Monte Carlo transport code. It allowed proper application of the results of transport calculations of β- particles emitted from radioactive 6He and reaching proportional detector active volume. In order to test the counter system and measuring procedure a number of experiments have been performed on PF devices. The experimental conditions have been simulated by means of MCNP5. The correctness of simulation outcome have been proved by measurements with known radioactive neutron source. The results of the DD fusion neutron measurements have been compared with other neutron diagnostics.

Modelling seasonal variations of natural radioactivity in soils: A case study in southern Italy

NASA Astrophysics Data System (ADS)

Guagliardi, Ilaria; Rovella, Natalia; Apollaro, Carmine; Bloise, Andrea; Rosa, Rosanna De; Scarciglia, Fabio; Buttafuoco, Gabriele

2016-12-01

The activity of natural radionuclides in soil has become an environmental concern for local public and national authorities because of the harmful effects of radiation exposure on human health. In this context, modelling and mapping the activity of natural radionuclides in soil is an important research topic. The study was aimed to model, in a spatial sense, the soil radioactivity in an urban and peri-urban soils area in southern Italy to analyse the seasonal influence on soil radioactivity. Measures of gamma radiation naturally emitted through the decay of radioactive isotopes (potassium, uranium and thorium) were analysed using a geostatistical approach to map the spatial distribution of soil radioactivity. The activity of three radionuclides was measured at 181 locations using a high-resolution ?-ray spectrometry. To take into account the influence of season, the measurements were carried out in summer and in winter. Activity data were analysed by using a geostatistical approach and zones of relatively high or low radioactivity were delineated. Among the main processes which influence natural radioactivity such as geology, geochemical, pedological, and ecological processes, results of this study showed a prominent control of radio-emission measurements by seasonal changes. Low natural radioactivity levels were measured in December associated with winter weather and moist soil conditions (due to high rainfall and low temperature), and higher activity values in July, when the soil was dry and no precipitations occurred.

EMERALD-NORMAL; PWR activity release and dose. [IBM360,370; FORTRAN IV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gillespie, S.G.; Brunot, W.K.

EMERALD-NORMAL is designed for the calculation of radiation releases and exposures resulting from normal operation of a large pressurized water reactor. The approach used is similar to an analog simulation of a real system. Each component or volume in the plant which contains a radioactive material is represented by a subroutine which keeps track of the production, transfer, decay, and absorption of radioactivity in that volume. During the course of the analysis, activity is transferred from subroutine to subroutine in the program as it would be transferred from place to place in the plant. Some of this activity is thenmore » released to the atmosphere and to the discharge canal. The rates of transfer, leakage, production, cleanup, decay, and release are read as input to the program. Subroutines are also included which calculate the off-site radiation exposures at various distances for individual isotopes and sums of isotopes. The program contains a library of physical data for the forty isotopes of most interest in licensing calculations, and other isotopes can be added or substituted. Because of the flexible nature of the simulation approach, the EMERALD-NORMAL program can be used for most calculations involving the production and release of radioactive material. These include design, operation, and licensing studies.IBM360,370; FORTRAN IV; OS/360,370; 576K bytes of memory.« less

Determination of (241)Pu by the method of disturbed radioactive equilibrium using 2πα-counting and precision gamma-spectrometry.

PubMed

Alekseev, I; Kuzmina, T

2016-04-01

A simple technique is proposed for the determination of the content of (241)Pu, which is based on disturbance of radioactive equilibrium in the genetically related (237)U←(241)Pu→(241)Am decay chain of radionuclides, with the subsequent use of 2πα-counting and precision gamma-spectroscopy for monitoring the process of restoration of that equilibrium. It has been shown that the data on dynamics of accumulation of the daughter (241)Am, which were obtained from the results of measurements of α- and γ-spectra of the samples, correspond to the estimates calculated for the chain of two genetically related radionuclides, the differences in the estimates of (241)Pu radioactivity not exceeding 2%. Combining the different methods of registration (2πα-counting, semiconductor alpha- and gamma-spectrometry) enables the proposed method to be efficiently applied both for calibration of (241)Pu-sources (from several hundreds of kBq and higher) and for radioisotopic analysis of plutonium mixtures. In doing so, there is a deep purification of (241)Pu from its daughter decay products required due to unavailability of commercial detectors that could make it possible, based only on analysis of alpha-spectra, to conduct quantitative analysis of the content of (238)Pu and (241)Am. Copyright © 2016 Elsevier Ltd. All rights reserved.

A 6He production facility and an electrostatic trap for measurement of the beta-neutrino correlation

NASA Astrophysics Data System (ADS)

Mukul, I.; Hass, M.; Heber, O.; Hirsh, T. Y.; Mishnayot, Y.; Rappaport, M. L.; Ron, G.; Shachar, Y.; Vaintraub, S.

2018-08-01

A novel experiment has been commissioned at the Weizmann Institute of Science for the study of weak interactions via a high-precision measurement of the beta-neutrinoangular correlation in the radioactive decay of short-lived 6He. The facility consists of a 14 MeV d + t neutron generator to produce atomic 6He, followed by ionization and bunching in an electron beam ion source, and injection into an electrostatic ion beam trap. This ion trap has been designed for efficient detection of the decay products from trapped light ions. The storage time in the trap for different stable ions was found to be in the range of 0.6 to 1.2 s at the chamber pressure of ∼7 × 10-10 mbar. We present the initial test results of the facility, and also demonstrate an important upgrade of an existing method (Stora et al., 2012) for production of light radioactive atoms, viz. 6He, for the precision measurement. The production rate of 6He atoms in the present setup has been estimated to be ∼ 1 . 45 × 10-4 atoms per neutron, and the system efficiency was found to be 4.0 ± 0.6%. An improvement to this setup is also presented for the enhanced production and diffusion of radioactive atoms for future use.

The positron excess as a smoking gun for dynamical dark matter?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dienes, Keith R.; Kumar, Jason; Thomas, Brooks

One of the most puzzling aspects of recent data from the AMS-02 experiment is an apparent rise in the cosmic-ray positron fraction as a function of energy. This feature is observed out to energies of approximately 350 GeV. One explanation of these results interprets the extra positrons as arising from the decays of dark-matter particles. This in turn typically requires that such particles have rather heavy TeV-scale masses and not undergo simple two-body decays to leptons. In this talk, by contrast, we show that Dynamical Dark Matter (DDM) can not only match existing AMS-02 data on the positron excess, butmore » also accomplish this feat with significantly lighter dark-matter constituents undergoing simple two-body decays to leptons. We also demonstrate that the Dynamical Dark Matter framework makes a fairly robust prediction that the positron fraction should level off and then remain roughly constant out to approximately 1 TeV, without experiencing any sharp downturns. Thus, if we interpret the positron excess in terms of decaying dark matter, the existence of a plateau in the positron fraction at energies less than 1 TeV may be taken as a “smoking gun” of Dynamical Dark Matter.« less

Determining the Minimal Required Radioactivity of 18F-FDG for Reliable Semiquantification in PET/CT Imaging: A Phantom Study.

PubMed

Chen, Ming-Kai; Menard, David H; Cheng, David W

2016-03-01

In pursuit of as-low-as-reasonably-achievable (ALARA) doses, this study investigated the minimal required radioactivity and corresponding imaging time for reliable semiquantification in PET/CT imaging. Using a phantom containing spheres of various diameters (3.4, 2.1, 1.5, 1.2, and 1.0 cm) filled with a fixed (18)F-FDG concentration of 165 kBq/mL and a background concentration of 23.3 kBq/mL, we performed PET/CT at multiple time points over 20 h of radioactive decay. The images were acquired for 10 min at a single bed position for each of 10 half-lives of decay using 3-dimensional list mode and were reconstructed into 1-, 2-, 3-, 4-, 5-, and 10-min acquisitions per bed position using an ordered-subsets expectation maximum algorithm with 24 subsets and 2 iterations and a gaussian 2-mm filter. SUVmax and SUVavg were measured for each sphere. The minimal required activity (±10%) for precise SUVmax semiquantification in the spheres was 1.8 kBq/mL for an acquisition of 10 min, 3.7 kBq/mL for 3-5 min, 7.9 kBq/mL for 2 min, and 17.4 kBq/mL for 1 min. The minimal required activity concentration-acquisition time product per bed position was 10-15 kBq/mL⋅min for reproducible SUV measurements within the spheres without overestimation. Using the total radioactivity and counting rate from the entire phantom, we found that the minimal required total activity-time product was 17 MBq⋅min and the minimal required counting rate-time product was 100 kcps⋅min. Our phantom study determined a threshold for minimal radioactivity and acquisition time for precise semiquantification in (18)F-FDG PET imaging that can serve as a guide in pursuit of achieving ALARA doses. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

High-precision branching-ratio measurement for the superallowed β+ emitter 26Alm

NASA Astrophysics Data System (ADS)

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Cross, D. S.; Demand, G.; Djongolov, M.; Ettenauer, S.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hackman, G.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Rand, E. T.; Sumithrarachchi, C. S.; Triambak, S.; Williams, S. J.

2012-05-01

A high-precision branching-ratio measurement for the superallowed β+ emitter 26Alm was performed at the TRIUMF-ISAC radioactive ion beam facility. An upper limit of ⩽12 ppm at 90% confidence level was found for the second forbidden β+ decay of 26Alm to the 21+ state at 1809 keV in 26Mg. An inclusive upper limit of ⩽15 ppm at 90% confidence level was found when considering all possible nonanalog β+/EC decay branches of 26Alm, resulting in a superallowed branching ratio of 100.0000-0.0015+0%.

Atmospheric emission of 137Cs82 from Beloyarsk nuclear power plant

NASA Astrophysics Data System (ADS)

Kolotkov, G. A.

2018-01-01

Citing Beloyarsk nuclear power plant (Russia) as an example, the problem of remote detection of radioactivity in the atmospheric pollution is examined. The comparative analysis of injected radionuclides into the atmosphere from the nuclear power plant with advanced fast neutron reactor is carried out. The main radionuclides throw out into the atmosphere from the nuclear power plant are beta-radionuclides. The secondary and tertiary spectra of beta-electrons decay for artificial radionuclide 137Cs82 is calculated, using Spencer-Fano’s equation. The averaged parameters of initial beta - electrons generated by 137Cs82 decay in the atmosphere is calculated.

Nuclear Data Sheets for A = 196

NASA Astrophysics Data System (ADS)

Xiaolong, Huang

2007-06-01

The 1998 version of nuclear data sheets for A = 196 has been revised and updated on the basis of the experimental results from various decay and reaction studies before January 2006. The experimental data for all known nuclei of A = 196 (Os,Ir,Pt,Au,Hg, Tl,Pb,Bi,Po,At,Rn) have been reevaluated. The experimental methods, references,Jπ arguments,and necessary comments are given in the text. Summary band structure drawings and level schemes from both radioactive decay and reaction studies are presented. Also of special interest are the new identification of superdeformed bands in 196Pb and 196Bi.

High precision measurements of 26Naβ- decay

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Svensson, C. E.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hardy, J. C.; Hyland, B.; Iacob, V. E.; Koopmans, K. A.; Kulp, W. D.; Leslie, J. R.; MacDonald, J. A.; Morton, A. C.; Ormand, W. E.; Osborne, C. J.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Wood, J. L.; Zganjar, E. F.

2005-04-01

High-precision measurements of the half-life and β-branching ratios for the β- decay of 26Na to 26Mg have been measured in β-counting and γ-decay experiments, respectively. A 4π proportional counter and fast tape transport system were employed for the half-life measurement, whereas the γ rays emitted by the daughter nucleus 26Mg were detected with the 8π γ-ray spectrometer, both located at TRIUMF's isotope separator and accelerator radioactive beam facility. The half-life of 26Na was determined to be T1/2=1.07128±0.00013±0.00021s, where the first error is statistical and the second systematic. The logft values derived from these experiments are compared with theoretical values from a full sd-shell model calculation.

Geoneutrinos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Machulin, I. N., E-mail: machulin@lngs.infn.it; Collaboration: Borexino Collaboration

2015-12-15

Academician M.A. Markov in the 1960s first proposed detecting the electron antineutrino in the reaction of inverse beta decay on a proton to study the processes inside the Earth. The radioactive isotopes {sup 238}U, {sup 232}Th, and {sup 40}K present in our planet decay with radiation of neutrinos (antineutrinos). Neutrinos that are produced reach the Earth’s surface practically without absorption and carry information about the internal structure of the planet. However, because of the smallness of the antineutrino fluxes and interaction cross sections with matter, antineutrinos of geological origin were first registered in only two experiments (Borexino and Kamland) inmore » recent years. The experimental observation of antineutrinos from the isotope decays in the depths of the Earth is the only way to study the radiation in our planetary interior.« less

PET Imaging: Basics and New Trends

NASA Astrophysics Data System (ADS)

Dahlbom, Magnus

Positron Emission Tomography or PET is a noninvasive molecular imaging method used both in research to study biology and disease, and clinically as a routine diagnostic imaging tool. In PET imaging, the subject is injected with a tracer labeled with a positron-emitting isotope and is then placed in a scanner to localize the radioactive tracer in the body. The localization of the tracer utilizes the unique decay characteristics of isotopes decaying by positron emission. In the PET scanner, a large number of scintillation detectors use coincidence detection of the annihilation radiation that is emitted as a result of the positron decay. By collecting a large number of these coincidence events, together with tomographic image reconstruction methods, the 3-D distribution of the radioactive tracer in the body can be reconstructed. Depending on the type of tracer used, the distribution will reflect a particular biological process, such as glucose metabolism when fluoro-deoxyglucose is used. PET has evolved from a relatively inefficient single-slice imaging system with relatively poor spatial resolution to an efficient, high-resolution imaging modality which can acquire a whole-body scan in a few minutes. This chapter will describe the basic physics and instrumentation used in PET. The various corrections that are necessary to apply to the acquired data in order to produce quantitative images are also described. Finally, some of the latest trends in instrumentation development are also discussed.

The first experimental investigation of the KLL Auger spectrum of Ni generated in the electron capture decay of radioactive 64Cu in a solid state matrix

NASA Astrophysics Data System (ADS)

Inoyatov, A. Kh.; Perevoshchikov, L. L.; Kovalík, A.; Filosofov, D. V.; Gorozhankin, V. M.; Ryšavý, M.

2012-09-01

The KLL Auger spectrum of Ni generated in the electron capture decay of radioactive 64Cu in a solid state matrix was measured for the first time using a combined electrostatic electron spectrometer adjusted to a 7 eV instrumental resolution. Energies and relative intensities of the all nine basic spectrum components were determined and compared with data obtained from X-ray induced spectra of metallic Ni and with theoretical results as well. Absolute energy of 6562.5 ± 1.3 eV (related to the Fermi level) measured for the dominant KL2L3(1D2) than a value obtained from the X-ray induced spectra which is probably caused by the effects of chemical bonding and physico-chemical environment. Moreover, it is higher by 20.4 eV (16 σ) than a prediction of the semi-empirical calculations by Larkins which indicates an influence of the "atomic structure effect" on absolute energies of the Auger transitions following the electron capture decay and, possibly, some imperfections in the calculations. Good agreement of the measured and predicted KL1L2(3P0/1P1) transition intensity ratios indicates perceptible influence of the relativistic effects on the KLL Auger spectrum even at Z = 28.

Attempts to Manipulate the Decay Time of Radioactive Nuclei

NASA Astrophysics Data System (ADS)

Fallin, B.; Grabow, B.; Tornow, W.

2008-04-01

It has been known for 20 years that electron screening strongly changes nuclear reaction cross sections at sub-Coulomb charged-particle projectile energies. The screening energy can be increased considerably if the target atoms are implanted in a metallic host and cooled to low temperature (T˜10 K). The large screening in metals derives from the Debye plasma model applied to the quasi-free metallic electrons. If ``time reversed,'' this model implies that the lifetime of radioactive nuclei placed in a metallic host can be manipulated by orders of magnitude. For α and β^+ decay one expects a shorter half-life, while for β^- decay and EC, a longer half-life is expected. The results of prior experiments testing this theory are controversial; about half of the published data confirm an effect, while the other half observe no effect. We will report on our experimental studies using ^64Cu and ^65Zn nuclei produced at TUNL via the ^63Cu(d,p) and ^65Cu(p,n) reactions, respectively. For ^64Cu, we detected the 511 keV annihilation γ rays and for ^65Zn the 1115.5 keV γ rays using HPGe detectors. In both cases we did not observe a half-life change outside experimental uncertainties between measurements at room temperature and those with the samples cooled to T=12 K.

Neutronic investigation and activation calculation for CFETR HCCB blankets

NASA Astrophysics Data System (ADS)

Shuling, XU; Mingzhun, LEI; Sumei, LIU; Kun, LU; Kun, XU; Kun, PEI

2017-12-01

The neutronic calculations and activation behavior of the proposed helium cooled ceramic breeder (HCCB) blanket were predicted for the Chinese Fusion Engineering Testing Reactor (CFETR) design model using the MCNP multi-particle transport code and its associated data library. The tritium self-sufficiency behavior of the HCCB blanket was assessed, addressing several important breeding-related arrangements inside the blankets. Two candidate first wall armor materials were considered to obtain a proper tritium breeding ratio (TBR). Presentations of other neutronic characteristics, including neutron flux, neutron-induced damages in terms of the accumulated dpa and helium production were also conducted. Activation, decay heat levels and contact dose rates of the components were calculated to estimate the neutron-induced radioactivity and personnel safety. The results indicate that neutron radiation is efficiently attenuated and slowed down by components placed between the plasma and toroidal field coil. The dominant nuclides and corresponding isotopes in the structural steel were discussed. A radioactivity comparison between pure beryllium and beryllium with specific impurities was also performed. After a millennium cooling time, the decay heat of all the concerned components and materials is less than 1 × 10-4 kW, and most associated in-vessel components qualify for recycling by remote handling. The results demonstrate that acceptable hands-on recycling and operation still require a further long waiting period to allow the activated products to decay.

Evaluation of naturally occurring radioactivity across the State of Kuwait using high-resolution gamma-ray spectrometry

NASA Astrophysics Data System (ADS)

Bajoga, A. D.; Alazemi, N.; Shams, H.; Regan, P. H.; Bradley, D. A.

2017-08-01

A study of natural radioactivity from 90 different soil samples from the state of Kuwait has been carried out to ascertain the NORM concentration values across the country. The calculated activity concentrations were determined from: (i) the decays of the 226Ra, 214Pb and 214Bi members of the 4n+2 decay chain headed by 238U and; (ii) the 228Ac, 212Pb and 208Tl members of the 4n chain headed by 232Th. The study also included evaluations for the 235U decay chain with the 186 keV doublet transition used together with the measured 4n+2 activity concentration values to determine the 235U/238U isotopic ratios for each sample. The values for the arithmetic mean activity concentrations for 90 separate locations across Kuwait as determined in the current work were 17.2, 14.1, and 368 Bq/kg, with standard deviations of 5.2, 3.7 and 90 Bq/kg for the 238U, 232Th and 40K activity concentrations respectively. Measured isotope ratios for 235U/238U give an arithmetic mean value for all of the samples of 0.045±0.003, consistent with that expected for natural uranium. These results indicate no evidence for a radiologically significant dispersion of additional depleted uranium across the entire State of Kuwait from the 1991 Gulf War.

Measurements of background radiation levels around Indian station Bharati, during 33rd Indian Scientific Expedition to Antarctica.

PubMed

Bakshi, A K; Prajith, Rama; Chinnaesakki, S; Pal, Rupali; Sathian, Deepa; Dhar, Ajay; Selvam, T Palani; Sapra, B K; Datta, D

2017-02-01

A comprehensive measurement of radioactivity concentrations of the primordial radionuclides 238 U, 232 Th and 40 K and their decay products in the soil samples collected from the sites of Indian research stations, Bharati and Maitri, at Antarctica was carried out using gamma spectrometric method. The activity concentrations in the soil samples of Bharati site were observed to be few times higher than of Maitri site. The major contributor to radioactivity content in the soil at Bharati site is 232 Th radionuclide in higher concentration. The gamma radiation levels based on the measured radioactivity of soil samples were calculated using the equation given in UNSCEAR 2000. The calculated radiation levels were compared with the measured values and found to correlate reasonably well. The study could be useful for the scientists working at Antarctica especially those at Indian station to take decision to avoid areas with higher radioactivity before erecting any facility for long term experiment or use. Copyright © 2016 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Bradley R.

The Hidden Cost of Nuclear Weapons The Cold War arms race drove an intense plutonium production program in the U.S. This campaign produced approximately 100 tons of plutonium over 40 years. The epicenter of plutonium production in the United States was the Hanford site, a 586 square mile reservation owned by the Department of Energy and located on the Colombia River in Southeastern Washington. Plutonium synthesis relied on nuclear reactors to convert uranium to plutonium within the reactor fuel rods. After a sufficient amount of conversion occurred, the rods were removed from the reactor and allowed to cool. They weremore » then dissolved in an acid bath and chemically processed to separate and purify plutonium from the rest of the constituents in the used reactor fuel. The acidic waste was then neutralized using sodium hydroxide and the resulting mixture of liquids and precipitates (small insoluble particles) was stored in huge underground waste tanks. The byproducts of the U.S. plutonium production campaign include over 53 million gallons of high-level radioactive waste stored in 177 large underground tanks at Hanford and another 34 million gallons stored at the Savannah River Site in South Carolina. This legacy nuclear waste represents one of the largest environmental clean-up challenges facing the world today. The nuclear waste in the Hanford tanks is a mixture of liquids and precipitates that have settled into sludge. Some of these tanks are now over 60 years old and a small number of them are leaking radioactive waste into the ground and contaminating the environment. The solution to this nuclear waste challenge is to convert the mixture of solids and liquids into a durable material that won't disperse into the environment and create hazards to the biosphere. What makes this difficult is the fact that the radioactive half-lives of some of the radionuclides in the waste are thousands to millions of years long. (The half-life of a radioactive substance is the amount of time it takes for one-half of the material to undergo radioactive decay.) In general, the ideal material would need to be durable for approximately 10 half-lives to allow the activity to decay to negligible levels. However, the potential health effects of each radionuclide vary depending on what type of radiation is emitted, the energy of that emission, and the susceptibility for the human body to accumulate and concentrate that particular element. Consequently, actual standards tend to be based on limiting the dose (energy deposited per unit mass) that is introduced into the environment. The Environmental Protection Agency (EPA) has the responsibility to establish standards for nuclear waste disposal to protect the health and safety of the public. For example, the Energy Policy Act of 1992 directed the EPA to establish radiation protection standards for the Yucca Mountain geologic repository for nuclear wastes. The standards for Yucca Mountain were promulgated in 2008, and limit the dose to 15 millirem per year for the first 10,000 years, and 100 milirem per year between 10,000 years and 1 million years (40 CFR Part 197; http://www.epa.gov/radiation/yucca/2008factsheet.html). So, the challenge is two-fold: (1) develop a material (a waste form) that is capable of immobilizing the waste over geologic time scales, and (2) develop a process to convert the radioactive sludge in the tanks into this durable waste form material. Glass: Hard, durable, inert, and with infinite chemical versatility Molten glass is a powerful solvent liquid, which can be designed to dissolve almost anything. When solidified, it can be one of the most chemically inert substances known to man. Nature's most famous analogue to glass is obsidian, a vitreous product of volcanic activity; formations over 17 million years old have been found. Archaeologists have found man-made glass specimens that are five thousand years old.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Selvi, Marco

For all experiments dealing with the rare event searches (neutrino, dark matter, neutrino-less double-beta decay), the reduction of the radioactive background is one of the most important and difficult tasks. There are basically two types of background, electron recoils and nuclear recoils. The electron recoil background is mostly from the gamma rays through the radioactive decay. The nuclear recoil background is from neutrons from spontaneous fission, (α, n) reactions and muoninduced interactions (spallations, photo-nuclear and hadronic interaction). The external gammas and neutrons from the muons and laboratory environment, can be reduced by operating the detector at deep underground laboratories andmore » by placing active or passive shield materials around the detector. The radioactivity of the detector materials also contributes to the background; in order to reduce it a careful screening campaign is mandatory to select highly radio-pure materials. In this review I present the status of current Monte Carlo simulations aimed to estimate and reproduce the background induced by gamma and neutron radioactivity of the materials and the shield of rare event search experiment. For the electromagnetic background a good level of agreement between the data and the MC simulation has been reached by the XENON100 and EDELWEISS experiments, using the GEANT4 toolkit. For the neutron background, a comparison between the yield of neutrons from spontaneous fission and (α, n) obtained with two dedicated softwares, SOURCES-4A and the one developed by Mei-Zhang-Hime, show a good overall agreement, with total yields within a factor 2 difference. The energy spectra from SOURCES-4A are in general smoother, while those from MZH presents sharp peaks. The neutron propagation through various materials has been studied with two MC codes, GEANT4 and MCNPX, showing a reasonably good agreement, inside 50% discrepancy.« less

Is Deuterium Nuclear Fusion Catalyzed by Antineutrinos?

NASA Astrophysics Data System (ADS)

Shomer, Isaac

2010-02-01

The hypothesis of Fischbach and Jenkins that neutrinos emitted from the sun accelerate radioactive decay is noted. It is thought that neutrinos accelerate beta decay by reacting with neutron-rich nuclides to form a beta particle and a daughter product, with no antineutrino emitted. Conversely, it is proposed that antineutrinos can react with proton-rich nuclides to cause positron decay, with no neutrino emitted. It is also proposed that the nuclear fusion of the hydrogen bomb is triggered not only by the energy of the igniting fission bomb, but by the antineutrinos created by the rapid beta decay of the daughter products in the fission process. The contemplated mechanism for antineutrino initiated fusion is the following: 1. The antineutrinos from the fission daughter products cause positron decay of deuterium by the process outlined above. 2. In a later fusion step, these positrons subsequently react with neutrons in deuterium to create antineutrinos. Electrons are unavailable to annihilate positrons in the plasma of the hydrogen bomb. 3. These antineutrinos thereafter react with more deuterium to form positrons, thereby propagating a chain reaction. )

426th Brookhaven Lecture

ScienceCinema

David Jaffe

2017-12-09

"The Pesky Neutrino". In this lecture, Jaffe describes the past, present and possible future of the "pesky" neutrino, the existence of which was first hypothesized in 1930 to rescue energy conservation in the radioactive beta decay of nuclei. Recent evidence that neutrinos are massive is the only experimental evidence in particle physics that is inconsistent with the Standard Model.

Making a Fish Tank Cloud Chamber

ERIC Educational Resources Information Center

Green, Frances

2012-01-01

The cloud chambers described here are large, made from readily available parts, simple to set up and always work. With no source in the chamber, background radiation can be observed. A large chamber means that a long rod containing a weakly radioactive material can be introduced, increasing the chance of seeing decays. Details of equipment and…

Teaching Elementary Particle Physics, Part II

ERIC Educational Resources Information Center

Hobson, Art

2011-01-01

In order to explain certain features of radioactive beta decay, Wolfgang Pauli suggested in 1930 that the nucleus emitted, in addition to a beta particle, another particle of an entirely new type. The hypothesized particle, dubbed the neutrino, would not be discovered experimentally for another 25 years. It's not easy to detect neutrinos, because…

Dictionary/handbook of nuclear medicine and clinical imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iturralde, M.P.

This book covers the following topics: Fundamentals of English medical etymology, Abbreviations, acronyms, symbols, denotations, and signs commonly used or defined in the dictionary, Characteristics of the elements, Characteristics of practicable radioisotopes and of selected radionuclides commonly used in nuclear medicine, Properties and production of radionuclides, Radioactive decay, Radiopharmaceuticals, and Radiation dosimetry.

Nuclear Cartography: Patterns in Binding Energies and Subatomic Structure

ERIC Educational Resources Information Center

Simpson, E. C.; Shelley, M.

2017-01-01

Nuclear masses and binding energies are some of the first nuclear properties met in high school physics, and can be used to introduce radioactive decays, fusion, and fission. With relatively little extension, they can also illustrate fundamental concepts in nuclear physics, such as shell structure and pairing, and to discuss how the elements…

Spectroscopy of neutron-rich nuclei at REX-ISOLDE with MINIBALL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroell, Th.

2007-08-15

We report on 'safe' Coulomb excitation of neutron-rich nuclei. The radioactive nuclei have been produced by ISOLDE at CERN and postaccelerated by the REX-ISOLDE facility. The {gamma} rays emitted by the decay of excited states have been detected by the MINIBALL array. Recent results are presented and compared to theoretical models.

Production and Evaluation of 236gNp and Reference Materials for Naturally Occurring Radioactive Materials

NASA Astrophysics Data System (ADS)

Larijani, Cyrus Kouroush

This thesis is based on the development of a radiochemical separation scheme capable of separating both 236gNp and 236Pu from a uranium target of natural isotopic composition ( 1 g uranium) and 200 MBq of fission decay products. The isobaric distribution of fission residues produced following the bombardment of a natural uranium target with a beam of 25 MeV protons has been evaluated. Decay analysis of thirteen isobarically distinct fission residues were carried out using high-resolution gamma-ray spectrometry at the UK National Physical Laboratory. Stoichiometric abundances were calculated via the determination of absolute activity concentrations associated with the longest-lived members of each isobaric chain. This technique was validated by computational modelling of likely sequential decay processes through an isobaric decay chain. The results were largely in agreement with previously published values for neutron bombardments on natural uranium at energies of 14 MeV. Higher relative yields of products with mass numbers A 110-130 were found, consistent with the increasing yield of these radionuclides as the bombarding energy is increased. Using literature values for the production cross-section for fusion of protons with uranium targets, it is estimated that an upper limit of approximately 250 Bq of activity from the 236Np ground state was produced in this experiment. Using a radiochemical separation scheme, Np and Pu fractions were separated from the produced fission decay products, with analyses of the target-based final reaction products made using Inductively Couple Plasma Mass Spectrometry (ICP-MS) and high-resolution alpha and gamma-ray spectrometry. In a separate research theme, reliable measurement of Naturally Occurring Radioactive Materials is of significance in order to comply with environmental regulations and for radiological protection purposes. The thesis describes the standardisation of three reference materials, namely Sand, Tuff and TiO2 which can serve as quality control materials to achieve traceability, method validation and instrument calibration. The sample preparation, material characterization via gamma, alpha and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the assignment of values for both the 4n Thorium and 4n + 2 Uranium decay series are presented.

Radiography apparatus using gamma rays emitted by water activated by fusion neutrons

DOEpatents

Smith, D.L.; Ikeda, Yujiro; Uno, Yoshitomo

1996-11-05

Radiography apparatus includes an arrangement for circulating pure water continuously between a location adjacent a source of energetic neutrons, such as a tritium target irradiated by a deuteron beam, and a remote location where radiographic analysis is conducted. Oxygen in the pure water is activated via the {sup 16}O(n,p){sup 16}N reaction using {sup 14}N-MeV neutrons produced at the neutron source via the {sup 3}H(d,n){sup 4}He reaction. Essentially monoenergetic gamma rays at 6.129 (predominantly) and 7.115 MeV are produced by the 7.13-second {sup 16}N decay for use in radiographic analysis. The gamma rays have substantial penetrating power and are useful in determining the thickness of materials and elemental compositions, particularly for metals and high-atomic number materials. The characteristic decay half life of 7.13 seconds of the activated oxygen is sufficient to permit gamma ray generation at a remote location where the activated water is transported, while not presenting a chemical or radioactivity hazard because the radioactivity falls to negligible levels after 1--2 minutes. 15 figs.

Shielding concepts for low-background proportional counter arrays in surface laboratories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aalseth, Craig E.; Humble, Paul H.; Mace, Emily K.

2016-02-01

Development of ultra low background gas proportional counters has made the contribution from naturally occurring radioactive isotopes – primarily and activity in the uranium and thorium decay chains – inconsequential to instrumental sensitivity levels when measurements are performed in above ground surface laboratories. Simple lead shielding is enough to mitigate against gamma rays as gas proportional counters are already relatively insensitive to naturally occurring gamma radiation. The dominant background in these surface laboratory measurements using ultra low background gas proportional counters is due to cosmic ray generated muons, neutrons, and protons. Studies of measurements with ultra low background gas proportionalmore » counters in surface and underground laboratories as well as radiation transport Monte Carlo simulations suggest a preferred conceptual design to achieve the highest possible sensitivity from an array of low background gas proportional counters when operated in a surface laboratory. The basis for a low background gas proportional counter array and the preferred shielding configuration is reported, especially in relation to measurements of radioactive gases having low energy decays such as 37Ar.« less

Pulsational Pair-instability Model for Superluminous Supernova PTF12dam:Interaction and Radioactive Decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tolstov, Alexey; Nomoto, Ken’ichi; Blinnikov, Sergei

2017-02-01

Being a superluminous supernova, PTF12dam can be explained by a {sup 56}Ni-powered model, a magnetar-powered model, or an interaction model. We propose that PTF12dam is a pulsational pair-instability supernova, where the outer envelope of a progenitor is ejected during the pulsations. Thus, it is powered by a double energy source: radioactive decay of {sup 56}Ni and a radiative shock in a dense circumstellar medium. To describe multicolor light curves and spectra, we use radiation-hydrodynamics calculations of the STELLA code. We found that light curves are well described in the model with 40 M {sub ⊙} ejecta and 20–40 M {submore » ⊙} circumstellar medium. The ejected {sup 56}Ni mass is about 6 M {sub ⊙}, which results from explosive nucleosynthesis with large explosion energy (2–3)×10{sup 52} erg. In comparison with alternative scenarios of pair-instability supernova and magnetar-powered supernova, in the interaction model, all the observed main photometric characteristics are well reproduced: multicolor light curves, color temperatures, and photospheric velocities.« less

Radiography apparatus using gamma rays emitted by water activated by fusion neutrons

DOEpatents

Smith, Donald L.; Ikeda, Yujiro; Uno, Yoshitomo

1996-01-01

Radiography apparatus includes an arrangement for circulating pure water continuously between a location adjacent a source of energetic neutrons, such as a tritium target irradiated by a deuteron beam, and a remote location where radiographic analysis is conducted. Oxygen in the pure water is activated via the .sup.16 O(n,p).sup.16 N reaction using .sup.14 -MeV neutrons produced at the neutron source via the .sup.3 H(d,n).sup.4 He reaction. Essentially monoenergetic gamma rays at 6.129 (predominantly) and 7.115 MeV are produced by the 7.13-second .sup.16 N decay for use in radiographic analysis. The gamma rays have substantial penetrating power and are useful in determining the thickness of materials and elemental compositions, particularly for metals and high-atomic number materials. The characteristic decay half life of 7.13 seconds of the activated oxygen is sufficient to permit gamma ray generation at a remote location where the activated water is transported, while not presenting a chemical or radioactivity hazard because the radioactivity falls to negligible levels after 1-2 minutes.

New limits for the 2 νββ decay of 96Zr to excited nuclear states of 96Mo

NASA Astrophysics Data System (ADS)

Finch, Sean; Tornow, Werner

2015-10-01

The final results from our search for the 2 νββ decay of 96Zr to excited 0+ and 2+ states of 96Mo are presented. Such measurements provide valuable test cases for 2 νββ -decay nuclear matrix element calculations, which in turn are used to tune 0 νββ -decay nuclear matrix element calculations. After undergoing double- β decay to an excited state, the excited daughter nucleus decays to the ground state, emitting two coincident γ rays. These two γ rays are detected in coincidence by two HPGe detectors sandwiching the 96Zr sample, with a NaI veto in anti-coincidence. This experimental apparatus, located at the Kimballton Underground Research Facility (KURF), has previously measured the 2 νββ decay of 100Mo and 150Nd to excited nuclear states. Experimental limits on the T1 / 2 and corresponding nuclear matrix element are presented for each of these decays. As a byproduct of this experiment, limits were also set on the single- β decay of 96Zr. Supported by DOE Grant: DE-FG02-97ER41033.

Influence of surface potential on the adhesive force of radioactive gold surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kweon, Hyojin; Yiacoumi, Sotira; Lee, Ida

2013-08-23

Radioactive particles may acquire surface potential through self-charging, and thus can behave differently from natural aerosols in atmospheric systems with respect to aggregation, deposition, resuspension, and transport to areas surrounding a radioactive source. Here, this work focuses on the adhesive force between radioactive particles and metallic surfaces, which relates to the deposition and resuspension of particles on surrounding surfaces. Scanning surface potential microscopy was employed to measure the surface potential of radioactive gold foil. Atomic force microscopy was used to investigate the adhesive force for gold that acquired surface charge either by irradiation or by application of an equivalent electricalmore » bias. Overall, the adhesive force increases with increasing surface potential or relative humidity. However, a behavior that does not follow the general trend was observed for the irradiated gold at a high decay rate. A comparison between experimental measurements and calculated values revealed that the surface potential promotes adhesion. The contribution of the electrostatic force at high levels of relative humidity was lower than the one found using theoretical calculations due to the effects caused by enhanced adsorption rate of water molecules under a high surface charge density. Lastly, the results of this study can be used to provide a better understanding of the behavior of radioactive particles in atmospheric systems.« less

Methods and Data Used to Investigate Polonium-210 as a Source of Excess Gross-Alpha Radioactivity in Ground Water, Churchill County, Nevada

USGS Publications Warehouse

Seiler, Ralph L.

2007-01-01

Ground water is the major source of drinking water in the Carson River Basin, California and Nevada. Previous studies have shown that uranium and gross-alpha radioactivities in ground water can be greater than U.S. Environmental Protection Agency Maximum Contaminant Levels, particularly in the Carson Desert, Churchill County, Nevada. Studies also have shown that the primary source of the gross-alpha radioactivity and alpha-emitting radionuclides in ground water is the dissolution of uranium-rich granitic rocks and basin-fill sediments that have their origins in the Sierra Nevada. However, ground water sampled from some wells in the Carson Desert had gross-alpha radioactivities greater than could be accounted for by the decay of dissolved uranium. The occurrence of polonium-210 (Po-210) was hypothesized to explain the higher than expected gross-alpha radioactivities. This report documents and describes the study design, field and analytical methods, and data used to determine whether Po-210 is the source of excess gross-alpha radioactivity in ground water underlying the Carson Desert in and around Fallon, Nevada. Specifically, this report presents: 1) gross alpha and uranium radioactivities for 100 wells sampled from June to September 2001; and 2) pH, dissolved oxygen, specific conductance, and Po-210 radioactivity for 25 wells sampled in April and June 2007. Results of quality-control samples for the 2007 dataset are also presented.

Modification of a method-of-characteristics solute-transport model to incorporate decay and equilibrium-controlled sorption or ion exchange

USGS Publications Warehouse

Goode, D.J.; Konikow, Leonard F.

1989-01-01

The U.S. Geological Survey computer model of two-dimensional solute transport and dispersion in ground water (Konikow and Bredehoeft, 1978) has been modified to incorporate the following types of chemical reactions: (1) first-order irreversible rate-reaction, such as radioactive decay; (2) reversible equilibrium-controlled sorption with linear, Freundlich, or Langmuir isotherms; and (3) reversible equilibrium-controlled ion exchange for monovalent or divalent ions. Numerical procedures are developed to incorporate these processes in the general solution scheme that uses method-of- characteristics with particle tracking for advection and finite-difference methods for dispersion. The first type of reaction is accounted for by an exponential decay term applied directly to the particle concentration. The second and third types of reactions are incorporated through a retardation factor, which is a function of concentration for nonlinear cases. The model is evaluated and verified by comparison with analytical solutions for linear sorption and decay, and by comparison with other numerical solutions for nonlinear sorption and ion exchange.

INNOVATIVE EASY-TO-USE PASSIVE TECHNIQUE FOR 222RN AND 220RN DECAY PRODUCT DETECTION.

PubMed

Mishra, Rosaline; Rout, R; Prajith, R; Jalalluddin, S; Sapra, B K; Mayya, Y S

2016-10-01

The decay products of radon and thoron are essentially the radioisotopes of polonium, bismuth and lead, and are solid particulates, which deposit in different parts of the respiratory tract upon inhalation, subsequently emitting high-energy alpha particles upon their radioactive decay. Development of passive deposition-based direct progeny sensors known as direct radon and thoron progeny sensors have provided an easy-to-use technique for time-integrated measurements of the decay products only. These dosemeters are apt for large-scale population dosimetry to assign inhalation doses to the public. The paper gives an insight into the technique, the calibration, comparison with the prevalently used active grab filter paper sampling technique, alpha track diameter analysis in these progeny sensors, progeny deposition velocity measurements carried out using these detector systems in the indoor as well as outdoor environment, and applications of these sensors for time-integrated unattached fraction estimation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Pulse shape discrimination performance of inverted coaxial Ge detectors

NASA Astrophysics Data System (ADS)

Domula, A.; Hult, M.; Kermaïdic, Y.; Marissens, G.; Schwingenheuer, B.; Wester, T.; Zuber, K.

2018-05-01

We report on the characterization of two inverted coaxial Ge detectors in the context of being employed in future 76Ge neutrinoless double beta (0 νββ) decay experiments. It is an advantage that such detectors can be produced with bigger Ge mass as compared to the planar Broad Energy Ge (BEGe) or p-type Point Contact (PPC) detectors that are currently used in the GERDA and MAJORANA DEMONSTRATOR 0 νββ decay experiments respectively. This will result in a lower background for the search of 0 νββ decay due to a reduction of detector surface to volume ratio, cables, electronics and holders which are dominating nearby radioactive sources. The measured resolution near the 76Ge Q-value at 2039 keV is 2.3 keV FWHM and their pulse-shape discrimination of background events are similar to BEGe and PPC detectors. It is concluded that this type of Ge-detector is suitable for usage in 76Ge 0 νββ decay experiments.

In situ calibration of a high-resolution gamma-ray borehole sonde for assaying uranium-bearing sandstone deposits

USGS Publications Warehouse

Day, J.H.

1985-01-01

A method is presented for assaying radioactive sandstone deposits in situ by using a high-resolution borehole gamma-ray spectrometer. Gamma-ray photopeaks from the same spectrum acquired to analyze a sample are used to characterize gamma-ray attenuation properties, from which a calibration function is determined. Assay results are independent of differences between properties of field samples and those of laboratory or test-hole standards generally used to calibrate a borehole sonde. This assaying technique is also independent of the state of radioactive disequilibrium that usually exists in nature among members of the natural-decay chains. ?? 1985.

Half-lives of 214Pb and 214Bi.

PubMed

Martz, D E; Langner, G H; Johnson, P R

1991-10-01

New measurements on chemically separated samples of 214Bi have yielded a mean half-life value of 19.71 +/- 0.02 min, where the error quoted is twice the standard deviation of the mean based on 23 decay runs. This result provides strong support for the historic 19.72 +/- 0.04 min half-life value and essentially excludes the 19.9-min value, both reported in previous studies. New measurements of the decay rate of 222Rn progeny activity initially in radioactive equilibrium have yielded a value of 26.89 +/- 0.03 min for the half-life of 214Pb, where the error quoted is twice the standard deviation of the mean based on 12 decay runs. This value is 0.1 min longer than the currently accepted 214Pb half-value of 26.8 min.

Beta-decay spectroscopy of neutron-rich 84-86Ga isotopes

NASA Astrophysics Data System (ADS)

Naqvi, Farheen; Xu, Zhengyu; Werner, Volker; Niikura, Megumi; Nishimura, Shunji; Eurica Collaboration

2013-10-01

The low lying excited states in 84-86 Ge were studied via the beta-gamma spectroscopy of 84-86 Ga nuclei. The study focused on the beta-delayed neutron emission probabilities and the beta-decay lifetimes, relevant for the astrophysical r process path in the region. The neutron-rich Ga isotopes were produced by in-flight fragmentation of 238U beam on a 9Be target. The experiment was performed at the Radioactive Ion Beam Facility (RIBF) at RIKEN, Japan. The BigRIPS spectrometer was utilized to identify and separate the reaction residues and the ions of interest were implanted in a segmented Si detector array called WASABI. Gamma rays emitted after the beta decay were identified by the EURICA array. Results of the ongoing analysis will be presented. Work supported by DOE grant no. DE-FG02-91ER-40609.

Principles of gross alpha and beta radioactivity detection in water.

PubMed

Semkow, T M; Parekh, P P

2001-11-01

A simultaneous detection of gross alpha and beta radioactivity was studied using gas proportional counting. This measurement is a part of a method mandated by US Environmental Protection Agency to screen for alpha and beta radioactivity in drinking water. Responses of a gas proportional detector to alpha and beta particles from several radionuclides were determined in drop and electroplated geometries. It is shown that, while the alpha radioactivity can be measured accurately in the presence of beta radioactivity, the opposite is not typically true due to alpha-to-beta crosstalk. The crosstalk, originating from the emission of conversion and Auger electrons as well as x rays, is shown to be dependent primarily on the particular alpha-decay scheme while the dependence on alpha energy is small but negligible. It was measured at 28-35% for 241Am, 22-24% for 230Th, and 4.9-6.5% for 239Pu. For 210Po, the crosstalk of 1.2-1.6% was observed mostly due to energy retardation. A method of reducing the crosstalk to a <3% level is proposed by absorbing the atomic electrons in a 6.2 mg cm(-2) Al absorber, at the same time decreasing the beta efficiency by 16-31%.

Remote monitoring of emission activity level from NPP using radiofrequencies 1420, 1665, 1667 MHz in real time.

PubMed

Kolotkov, Gennady; Penin, Sergei

2013-01-01

The Fukushima nuclear accident showed the importance of timely monitoring and detection of radioactive emissions released from enterprises of the nuclear fuel cycle. Nuclear power plants (NPP) working continuously are a stationary source of gas-aerosol emissions which presented in a ground surface layer persistently. Following radioactive emission, untypical effects can be observed, for example: the occurrences of areas with increased ionization, and increased concentration of some gases caused by photochemical reactions. The gases themselves and their characteristic radiation can be markers of radioactivity and can be monitored by a passive method. Hydrogen atom (H) and hydroxyl radical (OH) are formed in a radioactive plume by radiolysis of water molecules and other hydrogen-containing air components by the high energy electrons from beta-decay of radionuclides. The hydrogen atom and hydroxyl radical can spontaneously radiate at 1420 MHz and 1665-1667 MHz respectively. The passive method of remote monitoring of radiation levels using radio-frequencies of H and OH from radioactive emissions of NPP is described. The model data is indicative of the monitoring of radiation levels using these frequencies. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

High-resolution γ-ray spectroscopy: a versatile tool for nuclear β-decay studies at TRIUMF-ISAC

NASA Astrophysics Data System (ADS)

Ball, G. C.; Achtzehn, T.; Albers, D.; Khalili, J. S. Al; Andreoiu, C.; Andreyev, A.; Ashley, S. F.; Austin, R. A. E.; Becker, J. A.; Bricault, P.; Chan, S.; Chakrawarthy, R. S.; Churchman, R.; Coombes, H.; Cunningham, E. S.; Daoud, J.; Dombsky, M.; Drake, T. E.; Eshpeter, B.; Finlay, P.; Garrett, P. E.; Geppert, C.; Grinyer, G. F.; Hackman, G.; Hanemaayer, V.; Hyland, B.; Jones, G. A.; Koopmans, K. A.; Kulp, W. D.; Lassen, J.; Lavoie, J. P.; Leslie, J. R.; Litvinov, Y.; Macdonald, J. A.; Mattoon, C.; Melconian, D.; Morton, A. C.; Osborne, C. J.; Pearson, C. J.; Pearson, M.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Schumaker, M. A.; Schwarzenberg, J.; Scraggs, H. C.; Smith, M. B.; Svensson, C. E.; Valiente-Dobon, J. J.; Waddington, J. C.; Walker, P. M.; Wendt, K.; Williams, S. J.; Wood, J. L.; Zganjar, E. F.

2005-10-01

High-resolution γ-ray spectroscopy is essential to fully exploit the unique, high-quality beams available at the next generation of radioactive ion beam facilities such as the TRIUMF isotope separator and accelerator (ISAC). The 8π spectrometer, which consists of 20 Compton-suppressed HPGe detectors, has recently been reconfigured for a vigorous research programme in weak interaction and nuclear structure physics. With the addition of a variety of ancillary detectors it has become the world's most powerful device dedicated to β-decay studies. This paper provides a brief overview of the apparatus and highlights from recent experiments.

Measurement of DT neutron-induced activity in glass-microshell laser fusion targets

NASA Astrophysics Data System (ADS)

Lane, S. M.; Campbell, E. M.; Bennett, C.

1980-10-01

Laser fusion targets consisting of DT gas contained in Teflon-coated glass microshells produce 14.1-MeV neutrons that can interact with the (Si-28) nuclei in the glass to produce radioactive (Al-28). Using a very efficient collection-detection scheme that could detect the decay of 10% of the (Al-28) created, these nuclei are identified by their 1.78-MeV gamma ray, which decayed with a 2.2-min half-life. From the number of (Al-28) nuclei created and the neutron yield the compressed glass areal density was found to be 0.0059 g/sq cm.

Experiments on the origin of molecular chirality by parity non-conservation during beta-decay

NASA Technical Reports Server (NTRS)

Bonner, W. A.

1974-01-01

Experiments are described to test a theory for the origin of optical activity wherein the longitudinally polarized electrons resulting from parity violation during radioactive beta-decay, and their resulting circularly polarized bremsstrahlung, might interact asymmetrically with organic matter to yield optically active products. The historical background to this subject is briefly reviewed. Our experiments involve subjecting a number of racemic and optically active amino acid samples to a beta-radiation source for a period of 1.34 years (total dose: 411 Mrads), then examining them for any asymmetric effects by means of optical rotatory dispersion and analytical gas chromatography.

Bacterial Community Succession in Pine-Wood Decomposition.

PubMed

Kielak, Anna M; Scheublin, Tanja R; Mendes, Lucas W; van Veen, Johannes A; Kuramae, Eiko E

2016-01-01

Though bacteria and fungi are common inhabitants of decaying wood, little is known about the relationship between bacterial and fungal community dynamics during natural wood decay. Based on previous studies involving inoculated wood blocks, strong fungal selection on bacteria abundance and community composition was expected to occur during natural wood decay. Here, we focused on bacterial and fungal community compositions in pine wood samples collected from dead trees in different stages of decomposition. We showed that bacterial communities undergo less drastic changes than fungal communities during wood decay. Furthermore, we found that bacterial community assembly was a stochastic process at initial stage of wood decay and became more deterministic in later stages, likely due to environmental factors. Moreover, composition of bacterial communities did not respond to the changes in the major fungal species present in the wood but rather to the stage of decay reflected by the wood density. We concluded that the shifts in the bacterial communities were a result of the changes in wood properties during decomposition and largely independent of the composition of the wood-decaying fungal communities.

Bacterial Community Succession in Pine-Wood Decomposition

PubMed Central

Kielak, Anna M.; Scheublin, Tanja R.; Mendes, Lucas W.; van Veen, Johannes A.; Kuramae, Eiko E.

2016-01-01

Though bacteria and fungi are common inhabitants of decaying wood, little is known about the relationship between bacterial and fungal community dynamics during natural wood decay. Based on previous studies involving inoculated wood blocks, strong fungal selection on bacteria abundance and community composition was expected to occur during natural wood decay. Here, we focused on bacterial and fungal community compositions in pine wood samples collected from dead trees in different stages of decomposition. We showed that bacterial communities undergo less drastic changes than fungal communities during wood decay. Furthermore, we found that bacterial community assembly was a stochastic process at initial stage of wood decay and became more deterministic in later stages, likely due to environmental factors. Moreover, composition of bacterial communities did not respond to the changes in the major fungal species present in the wood but rather to the stage of decay reflected by the wood density. We concluded that the shifts in the bacterial communities were a result of the changes in wood properties during decomposition and largely independent of the composition of the wood-decaying fungal communities. PMID:26973611

Drum Centrifuge Study of the Transport of Leachates from Landfill Sites.

DTIC Science & Technology

1988-05-05

Radioactive decay and 5 reactions within the liquid phase itself will also contribute to changes in solute concentration. Such changes may affect the...7]m p A.2 AmIDII II Tue 133 Or A Luomew TRACu It would be possible to use a model polutant which might be present in a Ypercentage of Department of

HANDBOOK: SUB-SLAB DEPRESSURIZATION FOR LOW PERMEABILITY FILL MATERIAL DESIGN AND INSTALLATION OF A HOME RADON REDUCTION SYSTEM

EPA Science Inventory

Radon, a radioactive gas, comes from the natural decay of uranium. It moves to the earth's surface through tiny openings and cracks in soil and rocks. In outdoor air, radon is diluted to such low concentrations that it is usually nothing to worry about. However, radon can accumul...

Symposium Commemorating the 25th Anniversary of the Discovery of Mendelevium

DOE R&D Accomplishments Database

Seaborg, G. T. (ed.)

1980-03-28

The Symposium honoring the 25th Anniversary of the discovery of mendelevium was held at the Lawrence Berkeley Laboratory on March 28, 1980. The following three papers were presented: Chemical Properties of Mendelevium; Nuclear Properties of Mendelevium; and Radioactive Decay of Md Isotopes. Besides these papers there were introductory remarks, reminiscences, and concluding remarks.

Magneto-optical trapping of potassium isotopes

NASA Astrophysics Data System (ADS)

Williamson, Robert Sylvester, III

1997-12-01

We have demonstrated a magneto-optical trap (scMOT) suitable for capturing radioactive potassium produced on- line with the UW-Madison 12MeV tandem electrostatic accelerator. To do this, we made and characterized the first scMOT for potassium, measured the potassium ultracold collision rate, and developed a numerical trap- loading rate model that makes useful quantitative predictions. We have created a cold beam of collimated potassium atoms using a pyramidal magneto-optical funnel and used it to load a long-lifetime scMOT operating at ultrahigh vacuum. We have also built a target that produces a beam of radioactive 37K and 38K and coupled it to the magneto-optical funnel and trap. Once a trap of radioactive 38K has been demonstrated, the primary goal of this project is to measure the beta-asymmetry parameter in the decay of 38K, performing a sensitive test of the Standard Model of weak interactions.

Nuclear astrophysics with radioactive ions at FAIR

NASA Astrophysics Data System (ADS)

Reifarth, R.; Altstadt, S.; Göbel, K.; Heftrich, T.; Heil, M.; Koloczek, A.; Langer, C.; Plag, R.; Pohl, M.; Sonnabend, K.; Weigand, M.; Adachi, T.; Aksouh, F.; Al-Khalili, J.; AlGarawi, M.; AlGhamdi, S.; Alkhazov, G.; Alkhomashi, N.; Alvarez-Pol, H.; Alvarez-Rodriguez, R.; Andreev, V.; Andrei, B.; Atar, L.; Aumann, T.; Avdeichikov, V.; Bacri, C.; Bagchi, S.; Barbieri, C.; Beceiro, S.; Beck, C.; Beinrucker, C.; Belier, G.; Bemmerer, D.; Bendel, M.; Benlliure, J.; Benzoni, G.; Berjillos, R.; Bertini, D.; Bertulani, C.; Bishop, S.; Blasi, N.; Bloch, T.; Blumenfeld, Y.; Bonaccorso, A.; Boretzky, K.; Botvina, A.; Boudard, A.; Boutachkov, P.; Boztosun, I.; Bracco, A.; Brambilla, S.; Briz Monago, J.; Caamano, M.; Caesar, C.; Camera, F.; Casarejos, E.; Catford, W.; Cederkall, J.; Cederwall, B.; Chartier, M.; Chatillon, A.; Cherciu, M.; Chulkov, L.; Coleman-Smith, P.; Cortina-Gil, D.; Crespi, F.; Crespo, R.; Cresswell, J.; Csatlós, M.; Déchery, F.; Davids, B.; Davinson, T.; Derya, V.; Detistov, P.; Diaz Fernandez, P.; DiJulio, D.; Dmitry, S.; Doré, D.; Dueñas, J.; Dupont, E.; Egelhof, P.; Egorova, I.; Elekes, Z.; Enders, J.; Endres, J.; Ershov, S.; Ershova, O.; Fernandez-Dominguez, B.; Fetisov, A.; Fiori, E.; Fomichev, A.; Fonseca, M.; Fraile, L.; Freer, M.; Friese, J.; Borge, M. G.; Galaviz Redondo, D.; Gannon, S.; Garg, U.; Gasparic, I.; Gasques, L.; Gastineau, B.; Geissel, H.; Gernhäuser, R.; Ghosh, T.; Gilbert, M.; Glorius, J.; Golubev, P.; Gorshkov, A.; Gourishetty, A.; Grigorenko, L.; Gulyas, J.; Haiduc, M.; Hammache, F.; Harakeh, M.; Hass, M.; Heine, M.; Hennig, A.; Henriques, A.; Herzberg, R.; Holl, M.; Ignatov, A.; Ignatyuk, A.; Ilieva, S.; Ivanov, M.; Iwasa, N.; Jakobsson, B.; Johansson, H.; Jonson, B.; Joshi, P.; Junghans, A.; Jurado, B.; Körner, G.; Kalantar, N.; Kanungo, R.; Kelic-Heil, A.; Kezzar, K.; Khan, E.; Khanzadeev, A.; Kiselev, O.; Kogimtzis, M.; Körper, D.; Kräckmann, S.; Kröll, T.; Krücken, R.; Krasznahorkay, A.; Kratz, J.; Kresan, D.; Krings, T.; Krumbholz, A.; Krupko, S.; Kulessa, R.; Kumar, S.; Kurz, N.; Kuzmin, E.; Labiche, M.; Langanke, K.; Lazarus, I.; Le Bleis, T.; Lederer, C.; Lemasson, A.; Lemmon, R.; Liberati, V.; Litvinov, Y.; Löher, B.; Lopez Herraiz, J.; Münzenberg, G.; Machado, J.; Maev, E.; Mahata, K.; Mancusi, D.; Marganiec, J.; Martinez Perez, M.; Marusov, V.; Mengoni, D.; Million, B.; Morcelle, V.; Moreno, O.; Movsesyan, A.; Nacher, E.; Najafi, M.; Nakamura, T.; Naqvi, F.; Nikolski, E.; Nilsson, T.; Nociforo, C.; Nolan, P.; Novatsky, B.; Nyman, G.; Ornelas, A.; Palit, R.; Pandit, S.; Panin, V.; Paradela, C.; Parkar, V.; Paschalis, S.; Pawłowski, P.; Perea, A.; Pereira, J.; Petrache, C.; Petri, M.; Pickstone, S.; Pietralla, N.; Pietri, S.; Pivovarov, Y.; Potlog, P.; Prokofiev, A.; Rastrepina, G.; Rauscher, T.; Ribeiro, G.; Ricciardi, M.; Richter, A.; Rigollet, C.; Riisager, K.; Rios, A.; Ritter, C.; Rodriguez Frutos, T.; Rodriguez Vignote, J.; Röder, M.; Romig, C.; Rossi, D.; Roussel-Chomaz, P.; Rout, P.; Roy, S.; Söderström, P.; Saha Sarkar, M.; Sakuta, S.; Salsac, M.; Sampson, J.; Sanchez, J.; Rio Saez, del; Sanchez Rosado, J.; Sanjari, S.; Sarriguren, P.; Sauerwein, A.; Savran, D.; Scheidenberger, C.; Scheit, H.; Schmidt, S.; Schmitt, C.; Schnorrenberger, L.; Schrock, P.; Schwengner, R.; Seddon, D.; Sherrill, B.; Shrivastava, A.; Sidorchuk, S.; Silva, J.; Simon, H.; Simpson, E.; Singh, P.; Slobodan, D.; Sohler, D.; Spieker, M.; Stach, D.; Stan, E.; Stanoiu, M.; Stepantsov, S.; Stevenson, P.; Strieder, F.; Stuhl, L.; Suda, T.; Sümmerer, K.; Streicher, B.; Taieb, J.; Takechi, M.; Tanihata, I.; Taylor, J.; Tengblad, O.; Ter-Akopian, G.; Terashima, S.; Teubig, P.; Thies, R.; Thoennessen, M.; Thomas, T.; Thornhill, J.; Thungstrom, G.; Timar, J.; Togano, Y.; Tomohiro, U.; Tornyi, T.; Tostevin, J.; Townsley, C.; Trautmann, W.; Trivedi, T.; Typel, S.; Uberseder, E.; Udias, J.; Uesaka, T.; Uvarov, L.; Vajta, Z.; Velho, P.; Vikhrov, V.; Volknandt, M.; Volkov, V.; von Neumann-Cosel, P.; von Schmid, M.; Wagner, A.; Wamers, F.; Weick, H.; Wells, D.; Westerberg, L.; Wieland, O.; Wiescher, M.; Wimmer, C.; Wimmer, K.; Winfield, J. S.; Winkel, M.; Woods, P.; Wyss, R.; Yakorev, D.; Yavor, M.; Zamora Cardona, J.; Zartova, I.; Zerguerras, T.; Zgura, M.; Zhdanov, A.; Zhukov, M.; Zieblinski, M.; Zilges, A.; Zuber, K.

2016-01-01

The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.

THORON-SCOUT - first diffusion based active Radon and Thoron monitor

NASA Astrophysics Data System (ADS)

Wagner, W.; Streil, T.; Oeser, V.; Horak, G.; Duzynski, M.

2016-10-01

THORON-SCOUT is a stand-alone diffusion based active Radon and Thoron monitor for long term indoor measurements to evaluate the human health risk due to activity concentration in the breathing air. Alpha-particle spectroscopy of Po isotopes, being the progeny of the decay of the radioactive noble gas Radon, is applied to separately monitor activity contributions of 222Rn and 220Rn (Thoron) as well. In this work we show that the portion of Thoron (Tn) may locally be remarkable and even dominating and cannot be neglected as often has been assumed up to now. Along with tobacco consumption, Rn radioactivity turned out to be a dangerous cause of lung cancer, especially in older badly vented buildings situated in regions of radioactive geological formations. THORON-SCOUT allows a precise examination of the indoor atmosphere with respect to Rn and Inactivity concentration and, therefore, a realistic evaluation of corresponding health risk.

Approximating the r-Process on Earth with Thermonuclear Explosions. Lessons Learned and Unanswered Questions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becker, Stephen Allan

2016-01-28

During the astrophysical r-process, multiple neutron captures occur so rapidly on target nuclei that their daughter nuclei generally do not have time to undergo radioactive decay before another neutron is captured. The r-process can be approximately simulated on Earth in certain types of thermonuclear explosions through an analogous process of rapid neutron captures known as the "prompt capture" process. Between 1952 and 1969, 23 nuclear tests were fielded by the US which were involved (at least partially) with the "prompt capture" process. Of these tests, 15 were at least partially successful. Some of these tests were conducted under the Plowsharemore » Peaceful Nuclear Explosion Program as scientific research experiments. It is now known that the USSR conducted similar nuclear tests during 1966 to 1979. The elements einsteinium and fermium were first discovered by this process. The most successful tests achieved 19 successive neutron captures on the initial target nuclei. A review of the US program, target nuclei used, heavy element yields, scientific achievements of the program, and how some of the results have been used by the astrophysical community is given. Finally, some unanswered questions concerning very neutron-rich nuclei that could potentially have been answered with additional nuclear experiments is presented.« less

Characterization of low temperature metallic magnetic calorimeters having gold absorbers with implanted 163Ho ions

NASA Astrophysics Data System (ADS)

Gastaldo, L.; Ranitzsch, P. C.-O.; von Seggern, F.; Porst, J.-P.; Schäfer, S.; Pies, C.; Kempf, S.; Wolf, T.; Fleischmann, A.; Enss, C.; Herlert, A.; Johnston, K.

2013-05-01

For the first time we have investigated the behavior of fully micro-fabricated low temperature metallic magnetic calorimeters (MMCs) after undergoing an ion-implantation process. This experiment had the aim to show the possibility to perform a high precision calorimetric measurement of the energy spectrum following the electron capture of 163Ho using MMCs having the radioactive 163Ho ions implanted in the absorber. The isotope 163Ho decays through electron capture to 163Dy and features the smallest known QEC value. This peculiarity makes 163Ho a very interesting candidate to investigate the value of the electron neutrino mass by the analysis of the energy spectrum. The implantation of 163Ho ions was performed at ISOLDE-CERN. The performance of a detector that underwent an ion-implantation process is compared to the one of a detector without implanted ions. The results show that the implantation dose of ions used in this experiment does not compromise the properties of the detector. Moreover the performance of the detector prototype having the 163Ho ions implanted in the absorber is already close to the requirements needed for an experiment with sub-eV sensitivity to the electron neutrino mass. Based on these results, an optimized detector design for future 163Ho experiments is presented.

Charge breeding of radioactive isotopes at the CARIBU facility with an electron beam ion source

NASA Astrophysics Data System (ADS)

Vondrasek, R. C.; Dickerson, C. A.; Hendricks, M.; Ostroumov, P.; Pardo, R.; Savard, G.; Scott, R.; Zinkann, G.

2018-05-01

An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed at Argonne National Laboratory as part of the californium rare ion breeder upgrade. For the past year, the EBIS-CB has been undergoing commissioning as part of the ATLAS accelerator complex. It has delivered both stable and radioactive beams with A/Q < 6, breeding times <30 ms, low background contamination, and charge breeding efficiencies >18% into a single charge state. The operation of this device, challenges during the commissioning phase, and future improvements will be discussed.

Search for a Scalar Component in the Weak Interaction

NASA Astrophysics Data System (ADS)

Zakoucky, Dalibor; Baczyk, Pavel; Ban, Gilles; Beck, Marcus; Breitenfeldt, Martin; Couratin, Claire; Fabian, Xavier; Finlay, Paul; Flechard, Xavier; Friedag, Peter; Glück, Ferenc; Herlert, Alexander; Knecht, Andreas; Kozlov, Valentin; Lienard, Etienne; Porobic, Tomica; Soti, Gergelj; Tandecki, Michael; Vangorp, Simon; Weinheimer, Christian; Wursten, Elise; Severijns, Nathal

Weak interactions are described by the Standard Model which uses the basic assumption of a pure "V(ector)-A(xial vector)" character for the interaction. However, after more than half a century of model development and experimental testing of its fundamental ingredients, experimental limits for possible admixtures of scalar and/or tensor interactions are still as high as 7%. The WITCH project (Weak Interaction Trap for CHarged particles) at the isotope separator ISOLDE at CERN is trying to probe the structure of the weak interaction in specific low energy β-decays in order to look for possible scalar or tensor components or at least significantly improve the current experimental limits. This worldwide unique experimental setup consisting of a combination of two Penning ion traps and a retardation spectrometer allows to catch, trap and cool the radioactive nuclei provided by the ISOLDE separator, form a cooled and scattering-free radioactive source of β-decaying nuclei and let these nuclei decay at rest. The precise measurement of the shape of the energy spectrum of the recoiling nuclei, the shape of which is very sensitive to the character of the weak interaction, enables searching for a possible admixture of a scalar/tensor component in the dominant vector/axial vector mode. First online measurements with the isotope 35Ar were performed in 2011 and 2012. The current status of the experiment, the data analysis and results as well as extensive simulations will be presented and discussed.

Pile-up corrections for high-precision superallowed β decay half-life measurements via γ-ray photopeak counting

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Svensson, C. E.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hyland, B.; Kulp, W. D.; Leach, K. G.; Leslie, J. R.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Williams, S. J.; Wong, J.; Wood, J. L.; Zganjar, E. F.

2007-09-01

A general technique that corrects γ-ray gated β decay-curve data for detector pulse pile-up is presented. The method includes corrections for non-zero time-resolution and energy-threshold effects in addition to a special treatment of saturating events due to cosmic rays. This technique is verified through a Monte Carlo simulation and experimental data using radioactive beams of Na26 implanted at the center of the 8π γ-ray spectrometer at the ISAC facility at TRIUMF in Vancouver, Canada. The β-decay half-life of Na26 obtained from counting 1809-keV γ-ray photopeaks emitted by the daughter Mg26 was determined to be T=1.07167±0.00055 s following a 27σ correction for detector pulse pile-up. This result is in excellent agreement with the result of a previous measurement that employed direct β counting and demonstrates the feasibility of high-precision β-decay half-life measurements through the use of high-purity germanium γ-ray detectors. The technique presented here, while motivated by superallowed-Fermi β decay studies, is general and can be used for all half-life determinations (e.g. α-, β-, X-ray, fission) in which a γ-ray photopeak is used to select the decays of a particular isotope.

Gamma Decay of Unbound Neutron-Hole States in 133Sn

NASA Astrophysics Data System (ADS)

Vaquero, V.; Jungclaus, A.; Doornenbal, P.; Wimmer, K.; Gargano, A.; Tostevin, J. A.; Chen, S.; Nácher, E.; Sahin, E.; Shiga, Y.; Steppenbeck, D.; Taniuchi, R.; Xu, Z. Y.; Ando, T.; Baba, H.; Garrote, F. L. Bello; Franchoo, S.; Hadynska-Klek, K.; Kusoglu, A.; Liu, J.; Lokotko, T.; Momiyama, S.; Motobayashi, T.; Nagamine, S.; Nakatsuka, N.; Niikura, M.; Orlandi, R.; Saito, T.; Sakurai, H.; Söderström, P. A.; Tveten, G. M.; Vajta, Zs.; Yalcinkaya, M.

2017-05-01

Excited states in the nucleus 133Sn, with one neutron outside the double magic 132Sn core, were populated following one-neutron knockout from a 134Sn beam on a carbon target at relativistic energies at the Radioactive Isotope Beam Factory at RIKEN. Besides the γ rays emitted in the decay of the known neutron single-particle states in 133Sn additional γ strength in the energy range 3.5-5.5 MeV was observed for the first time. Since the neutron-separation energy of 133Sn is low, Sn=2.402 (4 ) MeV , this observation provides direct evidence for the radiative decay of neutron-unbound states in this nucleus. The ability of electromagnetic decay to compete successfully with neutron emission at energies as high as 3 MeV above threshold is attributed to a mismatch between the wave functions of the initial and final states in the latter case. These findings suggest that in the region southeast of 132Sn nuclear structure effects may play a significant role in the neutron versus γ competition in the decay of unbound states. As a consequence, the common neglect of such effects in the evaluation of the neutron-emission probabilities in calculations of global β -decay properties for astrophysical simulations may have to be reconsidered.

Gamma-ray spectroscopy in the decay of (83)Se to levels of (83)Br.

PubMed

Krane, K S

2015-03-01

High-resolution γ ray spectroscopy experiments have been done to study the emissions from the radioactive decay of 22-min (83g)Se produced from neutron capture using samples of enriched (82)Se. Energy and intensity values have been obtained to roughly an order of magnitude greater precision than in previous studies. Based on energy sums, 2 new levels are proposed in the daughter (83)Br and one previously proposed level is shown to be doubtful. Some 25 new transitions appear to decay with the (83)Se halflife, about half of which can be accommodated among the previous or newly proposed levels. Several previous γ ray placements are shown to be inconsistent with the new determinations of the (83)Br energy levels, but cannot be accommodated anywhere else among the known levels. As a result of the missing γ ray placements, some of the β branchings in the decay to levels of (83)Br appear to be negative. Gamma rays from the 2.4-h decay of the daughter (83)Br to levels of (83)Kr have also been observed, along with decays of (81g)(,m)Se present as a small impurity in the enriched samples and also as a strong component in irradiated samples of natural Se. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gamma Decay of Unbound Neutron-Hole States in ^{133}Sn.

PubMed

Vaquero, V; Jungclaus, A; Doornenbal, P; Wimmer, K; Gargano, A; Tostevin, J A; Chen, S; Nácher, E; Sahin, E; Shiga, Y; Steppenbeck, D; Taniuchi, R; Xu, Z Y; Ando, T; Baba, H; Garrote, F L Bello; Franchoo, S; Hadynska-Klek, K; Kusoglu, A; Liu, J; Lokotko, T; Momiyama, S; Motobayashi, T; Nagamine, S; Nakatsuka, N; Niikura, M; Orlandi, R; Saito, T; Sakurai, H; Söderström, P A; Tveten, G M; Vajta, Zs; Yalcinkaya, M

2017-05-19

Excited states in the nucleus ^{133}Sn, with one neutron outside the double magic ^{132}Sn core, were populated following one-neutron knockout from a ^{134}Sn beam on a carbon target at relativistic energies at the Radioactive Isotope Beam Factory at RIKEN. Besides the γ rays emitted in the decay of the known neutron single-particle states in ^{133}Sn additional γ strength in the energy range 3.5-5.5 MeV was observed for the first time. Since the neutron-separation energy of ^{133}Sn is low, S_{n}=2.402(4)  MeV, this observation provides direct evidence for the radiative decay of neutron-unbound states in this nucleus. The ability of electromagnetic decay to compete successfully with neutron emission at energies as high as 3 MeV above threshold is attributed to a mismatch between the wave functions of the initial and final states in the latter case. These findings suggest that in the region southeast of ^{132}Sn nuclear structure effects may play a significant role in the neutron versus γ competition in the decay of unbound states. As a consequence, the common neglect of such effects in the evaluation of the neutron-emission probabilities in calculations of global β-decay properties for astrophysical simulations may have to be reconsidered.

Conservaton and retrieval of information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, M.

This is a summary of the findings of a Nordic working group formed in 1990 and given the task of establishing a basis for a common Nordic view of the need for information conservation for nuclear waste repositories by investigating the following: (1) the type of information that should be conserved; (2) the form in which the information should be kept; (3) the quality of the information as regards both type and form; and (4) the problems of future retrieval of information, including retrieval after very long periods of time. High-level waste from nuclear power generation will remain radioactive formore » very long times even though the major part of the radioactivity will have decayed within 1000 yr. Certain information about the waste must be kept for long time periods because future generations may-intentionally or inadvertently-come into contact with the radioactive waste. Current day waste management would benefit from an early identification of documents to be part of an archive for radioactive waste repositories. The same reasoning is valid for repositories for other toxic wastes.« less

Q Value of the Superallowed Decay of {sup 46}V and Its Influence on V{sub ud} and the Unitarity of the Cabibbo-Kobayashi-Maskawa Matrix

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savard, G.; Department of Physics, University of Chicago, Chicago, Illinois 60637; Buchinger, F.

2005-09-02

The masses of the radioactive nuclei {sup 46}V and its decay daughter {sup 46}Ti have been measured with the Canadian Penning Trap on-line Penning trap mass spectrometer to a precision of 1x10{sup -8}. A Q{sub EC} value of 7052.90(40) keV for the superallowed beta decay of {sup 46}V is obtained from the difference of these two masses. With this precise Q value, the Ft value for this decay is determined with improved precision. An investigation of an earlier Q-value measurement for {sup 46}V uncovers a set of 7 measurements that cannot be reconciled with modern data and affects previous evaluationsmore » of V{sub ud} from superallowed Fermi decays. A new evaluation, adding our new data and removing the discredited subset, yields new values for G{sub V} and V{sub ud}. When combined with recent results for V{sub us}, this yields modified constraints for the unitarity of the Cabibbo-Kobayashi-Maskawa matrix and other extensions of the standard model.« less

First-forbidden β decay of ^17N and ^17Ne.

NASA Astrophysics Data System (ADS)

Millener, D. J.

1997-04-01

By measuring positrons in coincidence with 495-keV γ rays de-exciting the 1/2^+ first-excited state of ^17F, Borge et al.(M. J. B. Borge et al.), Phys. Lett. B 317, 25 (1993). have obtained a branch of 1.65(16)% for the first-forbidden β^+ decay of ^17Ne to the 1/2^+ state. This is a very interesting result because the measured branch is roughly a factor of two larger than expected on the basis of nuclear matrix elements which reproduce the corresponding β^- branch of 3.0%(A. R. Poletti and J. G. Pronko, Phys. Rev. C 8), 1285 (1973);D. E. Alburger and D. H. Wilkinson, Phys. Rev. C 13, 835 (1976). in the decay of ^17N. Recently, Ozawa et al.(A. Ozawa et al.), preprint RIKEN-AF-NP-238. have confirmed the magnitude of the β branch in ^17Ne decay, obtaining a value of 1.44(16)% by a method which utilizes a 32 MeV/A radioactive beam of ^17Ne. It is shown that differences, due to charge-dependent effects, in the ^17N and ^17Ne ground-state wave functions account for both β-decay branches.

Exploring the hidden interior of the Earth with directional neutrino measurements.

PubMed

Leyton, Michael; Dye, Stephen; Monroe, Jocelyn

2017-07-10

Roughly 40% of the Earth's total heat flow is powered by radioactive decays in the crust and mantle. Geo-neutrinos produced by these decays provide important clues about the origin, formation and thermal evolution of our planet, as well as the composition of its interior. Previous measurements of geo-neutrinos have all relied on the detection of inverse beta decay reactions, which are insensitive to the contribution from potassium and do not provide model-independent information about the spatial distribution of geo-neutrino sources within the Earth. Here we present a method for measuring previously unresolved components of Earth's radiogenic heating using neutrino-electron elastic scattering and low-background, direction-sensitive tracking detectors. We calculate the exposures needed to probe various contributions to the total geo-neutrino flux, specifically those associated to potassium, the mantle and the core. The measurements proposed here chart a course for pioneering exploration of the veiled inner workings of the Earth.

[Estimation of cost-saving for reducing radioactive waste from nuclear medicine facilities by implementing decay in storage (DIS) in Japan].

PubMed

Kida, Tetsuo; Hiraki, Hitoshi; Yamaguchi, Ichirou; Fujibuchi, Toshioh; Watanabe, Hiroshi

2012-01-01

DIS has not yet been implemented in Japan as of 2011. Therefore, even if risk was negligible, medical institutions have to entrust radioactive temporal waste disposal to Japan Radio Isotopes Association (JRIA) in the current situation. To decide whether DIS should be implemented in Japan or not, cost-saving effect of DIS was estimated by comparing the cost that nuclear medical facilities pay. By implementing DIS, the total annual cost for all nuclear medical facilities in Japan is estimated to be decreased to 30 million yen or less from 710 million yen. DIS would save 680 million yen (96%) per year.

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, Larry R.; Post Jr., Douglass E.; Dawson, John M.

1986-06-03

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, Larry R.; Post, Jr., Douglass E.; Dawson, John M.

1986-01-01

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Finite element code FENIA verification and application for 3D modelling of thermal state of radioactive waste deep geological repository

NASA Astrophysics Data System (ADS)

Butov, R. A.; Drobyshevsky, N. I.; Moiseenko, E. V.; Tokarev, U. N.

2017-11-01

The verification of the FENIA finite element code on some problems and an example of its application are presented in the paper. The code is being developing for 3D modelling of thermal, mechanical and hydrodynamical (THM) problems related to the functioning of deep geological repositories. Verification of the code for two analytical problems has been performed. The first one is point heat source with exponential heat decrease, the second one - linear heat source with similar behavior. Analytical solutions have been obtained by the authors. The problems have been chosen because they reflect the processes influencing the thermal state of deep geological repository of radioactive waste. Verification was performed for several meshes with different resolution. Good convergence between analytical and numerical solutions was achieved. The application of the FENIA code is illustrated by 3D modelling of thermal state of a prototypic deep geological repository of radioactive waste. The repository is designed for disposal of radioactive waste in a rock at depth of several hundred meters with no intention of later retrieval. Vitrified radioactive waste is placed in the containers, which are placed in vertical boreholes. The residual decay heat of radioactive waste leads to containers, engineered safety barriers and host rock heating. Maximum temperatures and corresponding times of their establishment have been determined.

Nuclear Data Sheets for A=159

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reich C. W.; Reich,C.W.

2012-01-01

The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A = 159 mass chain have been reviewed. Nuclides ranging from Pm (Z = 61) through Os (Z = 74) are included. These data are summarized and presented, together with adopted level schemes and properties. This work supersedes the previous evaluation of the data on these nuclides (2003He11).

Cryptology Management in a Quantum Computing Era

DTIC Science & Technology

2012-06-01

HOW IT WORKS (BLACK BOX) ...........................7 1. Schrodinger’s Cat Theory ......................7 2. Multiverse Theory...the macroscopic scale of an animal through the mechanism of a hammer activated by the decay of the radioactive substance. 2. Multiverse Theory...quantum mechanics is the multiverse theory. This theory states that at every decision, the universe splits into multiple copies; the number of copies is

Test of the electric charge conservation law with Borexino detector

NASA Astrophysics Data System (ADS)

Vishneva, A.; Agostini, M.; Appel, S.; Bellini, G.; Benziger, J.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chepurnov, A.; D' Angelo, D.; Davini, S.; Derbin, A.; Di Noto, L.; Drachnev, I.; Etenko, A.; Fomenko, K.; Franco, D.; Gabriele, F.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jedrzejczak, K.; Kaiser, M.; Kobychev, V.; Korablev, D.; Korga, G.; Kryn, D.; Laubenstein, M.; Lehnert, B.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Marcocci, S.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Mosteiro, P.; Muratova, V.; Neumair, B.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Roncin, R.; Rossi, N.; Schonert, S.; Semenov, D.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Thurn, J.; Toropova, M.; Unzhakov, E.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Weinz, S.; Winter, J.; Wojcik, M.; Wurm, M.; Yokley, Z.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

2016-02-01

The new limit on the electron lifetime is obtained from data of the Borexino experiment. The expected signal from the e → γν decay mode is a 256 keV photon detected in liquid scintillator. Because of the extremely low radioactive background level in the Borexino detector it was possible to improve the previous measurement by two orders of magnitude.

A radon daughter deposition model for low background experiments

NASA Astrophysics Data System (ADS)

Rielage, K.; Guiseppe, V. E.; Mastbaum, A.; Elliott, S. R.; Hime, A.

2009-05-01

The next generation low-background detectors operating underground, such as dark matter searches and neutrinoless double-beta decay, aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly ^222Rn) and its subsequent daughters present in an experiment are potential backgrounds, more troublesome is the deposition of radon daughters on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by daughters supported by the long half life (22 y) of ^210Pb on sensitive locations of a detector. An understanding of the potential surface contamination will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of daughters onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to deposit radon daughters on various surfaces under a controlled environment in order to develop a deposition model. Results from this test stand and the resulting deposition model will be presented.

Classification methodology for tritiated waste requiring interim storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cana, D.; Dall'ava, D.; Decanis, C.

2015-03-15

Fusion machines like the ITER experimental research facility will use tritium as fuel. Therefore, most of the solid radioactive waste will result not only from activation by 14 MeV neutrons, but also from contamination by tritium. As a consequence, optimizing the treatment process for waste containing tritium (tritiated waste) is a major challenge. This paper summarizes the studies conducted in France within the framework of the French national plan for the management of radioactive materials and waste. The paper recommends a reference program for managing this waste based on its sorting, treatment and packaging by the producer. It also recommendsmore » setting up a 50-year temporary storage facility to allow for tritium decay and designing future disposal facilities using tritiated radwaste characteristics as input data. This paper first describes this waste program and then details an optimized classification methodology which takes into account tritium decay over a 50-year storage period. The paper also describes a specific application for purely tritiated waste and discusses the set-up expected to be implemented for ITER decommissioning waste (current assumption). Comparison between this optimized approach and other viable detritiation techniques will be drawn. (authors)« less

The Discovery of Artificial Radioactivity

NASA Astrophysics Data System (ADS)

Guerra, Francesco; Leone, Matteo; Robotti, Nadia

2012-03-01

We reconstruct Frédéric Joliot and Irène Curie's discovery of artificial radioactivity in January 1934 based in part on documents preserved in the Joliot-Curie Archives in Paris, France. We argue that their discovery followed from the convergence of two parallel lines of research, on the neutron and on the positron, that were focused on a well-defined experimental problem, the nuclear transmutation of aluminum and other light elements. We suggest that a key role was played by a suggestion that Francis Perrin made at the seventh Solvay Conference at the end of October 1933, that the alpha-particle bombardment of aluminum produces an intermediate unstable isotope of phosphorus, which then decays by positron emission. We also suggest that a further idea that Perrin published in December 1933, and the pioneering theory of beta decay that Enrico Fermi also first published in December 1933, established a new theoretical framework that stimulated Joliot to resume the researches that he and Curie had interrupted after the Solvay Conference, now for the first time using a Geiger-Müller counter to detect the positrons emitted when he bombarded aluminum with polonium alpha particles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Y.; Fan, A.; Fiorillo, G.

Rare event search experiments, such as those searching for dark matter and observations of neutrinoless double beta decay, require ultra low levels of radioactive background for unmistakable identification. In order to reduce the radioactive background of detectors used in these types of event searches, low background photosensors are required, as the physical size of these detectors become increasing larger, and hence the number of such photosensors used also increases rapidly. Considering that most dark matter and neutrinoless double beta decay experiments are turning towards using noble liquids as the target choice, liquid xenon and liquid argon for instance, photosensors thatmore » can work well at cryogenic temperatures are required, 165 K and 87 K for liquid xenon and liquid argon, respectively. The Silicon Geiger Hybrid Tube (SiGHT) is a novel photosensor designed specifically for use in ultra low background experiments operating at cryogenic temperatures. It is based on the proven photocathode plus silicon photomultiplier (SiPM) hybrid technology and consists of very few other, but also ultra radio-pure, materials like fused silica and silicon for the SiPM. Lastly, the introduction of the SiGHT concept, as well as a feasibility study for its production, is reported in this article.« less

The BiPo-3 detector for the measurement of ultra low natural radioactivities of thin materials

NASA Astrophysics Data System (ADS)

Barabash, A. S.; Basharina-Freshville, A.; Birdsall, E.; Blondel, S.; Blot, S.; Bongrand, M.; Boursette, D.; Brudanin, V.; Busto, J.; Caffrey, A. J.; Calvez, S.; Cascella, M.; Cebrián, S.; Cerna, C.; Cesar, J. P.; Chauveau, E.; Chopra, A.; Dafní, T.; De Capua, S.; Duchesneau, D.; Durand, D.; Egorov, V.; Eurin, G.; Evans, J. J.; Fajt, L.; Filosofov, D.; Flack, R.; Garrido, X.; Gómez, H.; Guillon, B.; Guzowski, P.; Holý, K.; Hodák, R.; Huber, A.; Hugon, C.; Iguaz, F. J.; Irastorza, I. G.; Jeremie, A.; Jullian, S.; Kauer, M.; Klimenko, A.; Kochetov, O.; Konovalov, S. I.; Kovalenko, V.; Lang, K.; Lemière, Y.; Le Noblet, T.; Liptak, Z.; Liu, X. R.; Loaiza, P.; Lutter, G.; Luzón, G.; Macko, M.; Mamedov, F.; Marquet, C.; Mauger, F.; Morgan, B.; Mott, J.; Nemchenok, I.; Nomachi, M.; Nova, F.; Ohsumi, H.; Oliviéro, G.; Ortiz de Solórzano, A.; Pahlka, R. B.; Pater, J.; Perrot, F.; Piquemal, F.; Povinec, P.; Přidal, P.; Ramachers, Y. A.; Remoto, A.; Richards, B.; Riddle, C. L.; Rukhadze, E.; Saakyan, R.; Salazar, R.; Sarazin, X.; Shitov, Yu.; Simard, L.; Šimkovic, F.; Smetana, A.; Smolek, K.; Smolnikov, A.; Söldner-Rembold, S.; Soulé, B.; Štekl, I.; Thomas, J.; Timkin, V.; Torre, S.; Tretyak, Vl. I.; Tretyak, V. I.; Umatov, V. I.; Vilela, C.; Vorobel, V.; Waters, D.; Žukauskas, A.

2017-06-01

The BiPo-3 detector, running at the Canfranc Underground Laboratory (Laboratorio Subterr&aposaneo de Canfranc, LSC, Spain) since 2013, is a low-radioactivity detector dedicated to measuring ultra low natural radionuclide contaminations of 208Tl (232Th chain) and 214Bi (238U chain) in thin materials. The total sensitive surface area of the detector is 3.6 m2. The detector has been developed to measure the radiopurity of the selenium double β-decay source foils of the SuperNEMO experiment. In this paper the design and performance of the detector, and results of the background measurements in 208Tl and 214Bi, are presented, and the validation of the BiPo-3 measurement with a calibrated aluminium foil is discussed. Results of the 208Tl and 214Bi activity measurements of the first enriched 82Se foils of the double β-decay SuperNEMO experiment are reported. The sensitivity of the BiPo-3 detector for the measurement of the SuperNEMO 82Se foils is Script A(208Tl) <2 μBq/kg (90% C.L.) and Script A(214Bi) <140 μBq/kg (90% C.L.) after 6 months of measurement.

X-Ray Illumination of the Ejecta of Supernova 1987A

NASA Technical Reports Server (NTRS)

Larsson, J.; Fransson, C.; Oestlin, G.; Groeningsson, P.; Jerkstrand, A.; Kozma, C.; Sollerman, J.; Challis, P.; Kirshner, R. P.; Chevalier, R. A.;

Search for baryon number violation in top-quark decays

DOE PAGES

Chatrchyan, Serguei

2014-02-20

A search for baryon number violation (BNV) in top-quark decays is performed using pp collisions produced by the LHC at sqrt(s) = 8 TeV. The top-quark decay considered in this search results in one light lepton (muon or electron), two jets, but no neutrino in the final state. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.5 inverse femtobarns. The event selection is optimized for top quarks produced in pairs, with one undergoing the BNV decay and the other the standard model hadronic decay to three jets. No significant excessmore » of events over the expected yield from standard model processes is observed. The upper limits at 95% confidence level on the branching fraction of the BNV top-quark decay are calculated to be 0.0016 and 0.0017 for the muon and the electron channels, respectively. Assuming lepton universality, an upper limit of 0.0015 results from the combination of the two channels. These limits are the first that have been obtained on a BNV process involving the top quark.« less

Activity computer program for calculating ion irradiation activation

NASA Astrophysics Data System (ADS)

Palmer, Ben; Connolly, Brian; Read, Mark

2017-07-01

A computer program, Activity, was developed to predict the activity and gamma lines of materials irradiated with an ion beam. It uses the TENDL (Koning and Rochman, 2012) [1] proton reaction cross section database, the Stopping and Range of Ions in Matter (SRIM) (Biersack et al., 2010) code, a Nuclear Data Services (NDS) radioactive decay database (Sonzogni, 2006) [2] and an ENDF gamma decay database (Herman and Chadwick, 2006) [3]. An extended version of Bateman's equation is used to calculate the activity at time t, and this equation is solved analytically, with the option to also solve by numeric inverse Laplace Transform as a failsafe. The program outputs the expected activity and gamma lines of the activated material.

The MAJORANA Demonstrator Radioassay Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abgrall, N.; Arnquist, Isaac J.; Avignone, F. T.

2016-05-03

The Majorana collaboration is constructing the Majorana Demonstrator at the Sanford Underground Research Facility at the Homestake gold mine, in Lead, SD. The apparatus will use Ge detectors, enriched in isotope 76Ge, to demonstrate the feasibility of a large-scale Ge detector experiment to search for neutrinoless double beta decay. The long half-life of this postulated process requires that the apparatus be extremely low in radioactive isotopes whose decays may produce backgrounds to the search. The radioassay program conducted by the collaboration to ensure that the materials comprising the apparatus are suffciently pure is described. The resulting measurements of the radioactiveisotopemore » contamination for a number of materials studied for use in the detector are reported.« less

SN 1985f - Death of a Wolf-Rayet star

NASA Technical Reports Server (NTRS)

Begelman, M. C.; Sarazin, C. L.

1986-01-01

The optical spectrum of SN 1985f has been analyzed, and the supernova ejecta is shown to contain approximately 5 or more solar masses of oxygen and very little hydrogen. It is suggested that the explosion resulted from the pair instability supernova of a WO Wolf-Rayet star of about 50 solar masses, and that the optical luminosity of the supernova is powered by the radioactive decay of Co-56 synthesized in the explosion. As calculated from the rate of the optical emission decay, the explosion occurred about 350 days before its discovery in February, 1985. It is believed that some of the oxygen-rich supernova remnants may also have been produced by explosions of WO stars.

The rate of decay of fresh fission products from a nuclear reactor

NASA Astrophysics Data System (ADS)

Dolan, David J.

Determining the rate of decay of fresh fission products from a nuclear reactor is complex because of the number of isotopes involved, different types of decay, half-lives of the isotopes, and some isotopes decay into other radioactive isotopes. Traditionally, a simplified rule of 7s and 10s is used to determine the dose rate from nuclear weapons and can be to estimate the dose rate from fresh fission products of a nuclear reactor. An experiment was designed to determine the dose rate with respect to time from fresh fission products of a nuclear reactor. The experiment exposed 0.5 grams of unenriched Uranium to a fast and thermal neutron flux from a TRIGA Research Reactor (Lakewood, CO) for ten minutes. The dose rate from the fission products was measured by four Mirion DMC 2000XB electronic personal dosimeters over a period of six days. The resulting dose rate following a rule of 10s: the dose rate of fresh fission products from a nuclear reactor decreases by a factor of 10 for every 10 units of time.

Search for new physics in a precise 20F beta spectrum shape measurement

NASA Astrophysics Data System (ADS)

George, Elizabeth; Voytas, Paul; Chuna, Thomas; Naviliat-Cuncic, Oscar; Gade, Alexandra; Hughes, Max; Huyan, Xueying; Liddick, Sean; Minamisono, Kei; Paulauskas, Stanley; Weisshaar, Dirk; Ban, Gilles; Flechard, Xavier; Lienard, Etienne

2015-10-01

We are carrying out a measurement of the shape of the energy spectrum of β particles from 20F decay. We aim to achieve a relative precision below 3%, representing an order of magnitude improvement compared to previous experiments. This level of precision will enable a test of the so-called strong form of the conserved vector current (CVC) hypothesis, and should also enable us to place competitive limits on the contributions of exotic tensor couplings in beta decay. In order to control systematic effects, we are using a technique that takes advantage of high energy radioactive beams at the NSCL to implant the decaying nuclei in a scintillation detector deep enough that the emitted beta particles cannot escape. The β-particle energy is measured with the implantation detector after switching off the beam implantation. Ancillary detectors are used to tag the 1.633-MeV γ-rays following the β decay for coincidence measurements in order to reduce backgrounds. We will give an overview and report on the status of the experiment.

The characterization and risk assessment of the `Red Forest` radioactive waste burial site at Chernobyl Nuclear Power Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bungai, D.A.; Skalskij, A.S.; Dzhepo, S.P.

The `Red Forest` radioactive waste burials created during emergency clean-up activities at Chernobyl Nuclear Power Plant represent a serious source of radioactive contamination of the local ground water system with 9OSr concentration in ground water exceeding the drinking water standard by 3-4 orders of magnitude. In this paper we present results of our hydrogeological and radiological `Red Forest` site characterization studies, which allow us to estimate 9OSr subsurface migration parameters. We use then these parameters to assess long terrain radionuclide transport to groundwater and surface water, and to analyze associated health risks. Our analyses indicate that 9OSr transport via groundmore » water pathway from `Red Forest` burials to the adjacent Pripyat River is relatively insignificant due to slow release of 9OSr from the waste burials (less than 1% of inventory per year) and due to long enough ground water residence time in the subsurface, which allows substantial decay of the radioactive contaminant. Tins result and our previous analyses indicate, that though conditions of radioactive waste storage in burials do not satisfy Ukrainian regulation on radiation protection, health risks caused by radionuclide migration to ground water from `Red Forest` burials do not justify application of expensive countermeasures.« less

Detachment-limited erosion, alluvial transport, and relief in decaying landscapes

NASA Astrophysics Data System (ADS)

Johnstone, S. A.; Hilley, G. E.

2013-12-01

The correspondence between relief and erosion rates in tectonically active orogens suggests that erosion rates and relief adjust relatively rapidly to changes in the rates of tectonic processes. This rapid landscape response is at odds with the preservation of ancient orogens for 10s to 100s of millions of years after orogenesis has ceased. We hypothesize that this hysteresis in response times to the acceleration versus deceleration of tectonic rates results from a geomorphic process transition in fluvial networks. In steep landscapes found in tectonically active environments erosion is largely controlled by detachment-limited incision, whereas the increasing importance of alluvial transport in decaying landscapes controls relief and response time-scales in these situations. We present results from one-dimensional (profile) numerical modeling of channels undergoing topographic decay from an initial steady state following a cessation in uplift to understand process transitions that may reconcile the large differences in response times implied by active versus ancient mountain-belts. We performed dimensional analysis on the governing equations such that relief in the channels, process transitions between alluvial transport and detachment-limited erosion, and response times could be viewed in terms of dimensionless numbers that capture the relative strength of sediment transport, bedrock incision, and the initial uplift rate. We found that the form of the decaying profile is dictated by the relative ability of a system to incise vs. transport sediment. When sediment transport is inefficient relative to bedrock incision, models suggest that relief decays in a manner that preserves the overall channel profile geometry as channel slopes decline. In contrast, when the ability of a system to transport sediment greatly exceeds its ability to incise bedrock, decay will be dominated by the consumption of topography by slope retreat. We find that the declivity of the surface along which slopes retreat is set by the sediment transport slope of the fluvial network. As slope retreat progresses, the fraction of area undergoing rapid erosion (and therefore the sediment flux) decreases, which causes a perpetual decline in the sediment transport slope itself. This is manifest as a headward migrating transition from areas dominated by slope retreat to slope decline. While this behavior occurs to some degree in all simulations undergoing slope retreat, it is only clearly observed when steady state alluvial transport slopes are comparable to, but smaller than, bedrock incision slopes. For a given length scale we find that the evolution of relief through time, measured as the fraction of initial relief preserved, is independent of dimensionless fluvial erosion and transport coefficients. High sediment transport slopes can act to limit the rate of decay of relief in landscapes evolving by slope retreat. However, because slope decline occupies only the downstream portion of drainage networks in these cases, the majority of the relief reduction is typically accomplished by slope retreat. These results highlight the importance of erosional process transitions in shaping the relief of decaying landscapes.

Predicting the fate of sediment and pollutants in river floodplains.

PubMed

Malmon, Daniel V; Dunne, Thomas; Reneau, Steven L

2002-05-01

Geological processes such as erosion and sedimentation redistribute toxic pollutants introduced to the landscape by mining, agriculture, weapons development, and other human activities. A significant portion of these contaminants is insoluble, adsorbing to soils and sediments after being released. Geologists have long understood that much of this sediment is stored in river floodplains, which are increasingly recognized as important nonpoint sources of pollution in rivers. However, the fate of contaminated sediment has generally been analyzed using hydrodynamic models of in-channel processes, ignoring particle exchange with the floodplain. Here, we present a stochastic theory of sediment redistribution in alluvial valley floors that tracks particle-bound pollutants and explicitly considers sediment storage within floodplains. We use the theory to model the future redistribution and radioactive decay of 137Cs currently stored on sediment in floodplains at the Los Alamos National Laboratory (LANL) in New Mexico. Model results indicate that floodplain storage significantly reduces the rate of sediment delivery from upper Los Alamos Canyon, allowing 50% of the 137Cs currently residing in the valley floor to decay radioactively before leaving LANL. A sensitivity analysis shows that the rate of sediment overturn in the valley (and hence, the total amount of radioactive 137Cs predicted to leave LANL) is significantly controlled by the rate of sediment exchange with the floodplain. Our results emphasize that flood plain sedimentation and erosion processes can strongly influence the redistribution of anthropogenic pollutants in fluvial environments. We introduce a new theoretical framework for examining this interaction, which can provide a scientific basis for decision-making in a wide range of river basin management scenarios.

EMERALD REV.1. PWR Accident Activity Release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brunot, W.K.; Fray, R.R.; Gillespie, S.G.

1975-10-01

The EMERALD program is designed for the calculation of radiation releases and exposures resulting from abnormal operation of a large pressurized water reactor (PWR). The approach used in EMERALD is similar to an analog simulation of a real system. Each component or volume in the plant which contains a radioactive material is represented by a subroutine which keeps track of the production, transfer, decay and absorption of radioactivity in that volume. During the course of the analysis of an accident, activity is transferred from subroutine to subroutine in the program as it would be transferred from place to place inmore » the plant. For example, in the calculation of the doses resulting from a loss-of-coolant accident the program first calculates the activity built up in the fuel before the accident, then releases some of this activity to the containment volume. Some of this activity is then released to the atmosphere. The rates of transfer, leakage, production, cleanup, decay, and release are read in as input to the program. Subroutines are also included which calculate the on-site and off-site radiation exposures at various distances for individual isotopes and sums of isotopes. The program contains a library of physical data for the twenty-five isotopes of most interest in licensing calculations, and other isotopes can be added or substituted. Because of the flexible nature of the simulation approach, the EMERALD program can be used for most calculations involving the production and release of radioactive materials during abnormal operation of a PWR. These include design, operational, and licensing studies.« less

EMERALD REV. 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brunot, W.K.; Fray, R.R.; Gillespie, S.G.

1974-03-01

The EMERALD program is designed for the calculation of radiation releases and exposures resulting from abnormal operation of a large pressurized water reactor (PWR). The approach used in EMERALD is similar to an analog simulation of a real system. Each component or volume in the plant which contains a radioactive material is represented by a subroutine which keeps track of the production, transfer, decay and absorption of radioactivity in that volume. During the course of the analysis of an accident, activity is transferred from subroutine to subroutine in the program as it would be transferred from place to place inmore » the plant. For example, in the calculation of the doses resulting from a loss-of-coolant accident the program first calculates the activity built up in the fuel before the accident, then releases some of this activity to the containment volume. Some of this activity is then released to the atmosphere. The rates of transfer, leakage, production, cleanup, decay, and release are read in as input to the program. Subroutines are also included which calculate the on-site and off-site radiation exposures at various distances for individual isotopes and sums of isotopes. The program contains a library of physical data for the twenty-five isotopes of most interest in licensing calculations, and other isotopes can be added or substituted. Because of the flexible nature of the simulation approach, the EMERALD program can be used for most calculations involving the production and release of radioactive materials during abnormal operation of a PWR. These include design, operational, and licensing studies.« less

Special Analysis: 2016-001 Analysis of the Potential Under-Reporting of Am-241 Inventory for Nitrate Salt Waste at Area G

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, Shaoping; Stauffer, Philip H.; Birdsell, Kay Hanson

The Los Alamos National Laboratory (LANL) generates radioactive waste as a result of various activities. Operational waste is generated from a wide variety of research and development activities including nuclear weapons development, energy production, and medical research. Environmental restoration (ER), and decontamination and decommissioning (D&D) waste is generated as contaminated sites and facilities at LANL undergo cleanup or remediation. The majority of this waste is low-level radioactive waste (LLW) and is disposed of at the Technical Area 54 (TA-54), Area G disposal facility.

Probing the photon polarization in B → K*γ with conversion

DOE PAGES

Bishara, Fady; Robinson, Dean J.

2015-09-02

We re-examine the possibility to measure the photon polarization in B → K*γ decays, via decays in which the photon subsequently undergoes nuclear conversion to a lepton pair. We obtain compact expressions for the full decay-plus-conversion amplitude. With these results we show that interference between the B → (K* → Kπ)γ decay and the γN → ℓ + ℓ – N conversion permits both the ratio and relative weak phase between the left- and right-handed photon amplitudes to be probed by an angular observable, constructed from the final state dilepton, kaon and pion kinematic configuration. Exploiting this technique will bemore » experimentally challenging. However, we present special kinematic cuts that enhance the statistical power of this technique by an O(1) factor. Furthermore, we verify this effect and extract pertinent angular kinematic distributions with dedicated numerical simulations.« less

β+ decay and cosmic-ray half-life of 91Nb

NASA Astrophysics Data System (ADS)

Hindi, M. M.; Sur, Bhaskar; Wedding, Kristin L.; Bardayan, D. W.; Czerwinski, K. R.; da Cruz, M. T. F.; Hoffman, D. C.; Larimer, R.-M.; Lesko, K. T.; Norman, Eric B.

1993-06-01

In the laboratory, 91Nb decays by electron capture with a 680-yr half-life. However, as a high energy cosmic ray, it would be stripped of its atomic electrons and would be able to undergo only β+ decay. We produced and chemically purified a sample of 91Nb and observed its decay with an array of Ge and NaI detectors. By following the β+ annihilation radiation, we were able to determine the β+ branching ratios of both the 105-keV, 61-d isomer and the ground state of 91Nb. The ground-state branch is (7.7+/-0.8)×10-3% leading to a β+ partial half-like of (8.8+/-1.9)×106 yr. Such a value of the half-life makes 91Nb a good candidate for determining the confinement time of this secondary component of the cosmic rays.

Double-beta decay investigation with highly pure enriched $$^{82}$$Se for the LUCIFER experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beeman, J. W.; Bellini, F.; Benetti, P.

2015-12-13

The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of 82Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched 82Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched 82Se metal, measured with a high-purity germanium detector at themore » Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of 232Th, 238U and 235U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the 82Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of 82Se to 0+1, 2+2 and 2+1 excited states of 82Kr of 3.4•10 22, 1.3•10 22 and 1.0•10 22 y, respectively, with a 90 % C.L.« less

The nucleus is the target for radiation-induced chromosomal instability

NASA Technical Reports Server (NTRS)

Kaplan, M. I.; Morgan, W. F.

1998-01-01

We have previously described chromosomal instability in cells of a human-hamster hybrid cell line after exposure to X rays. Chromosomal instability in these cells is characterized by the appearance of novel chromosomal rearrangements multiple generations after exposure to ionizing radiation. To identify the cellular target(s) for radiation-induced chromosomal instability, cells were treated with 125I-labeled compounds and frozen. Radioactive decays from 125I cause damage to the cell primarily at the site of their decay, and freezing the cells allows damage to accumulate in the absence of other cellular processes. We found that the decay of 125I-iododeoxyuridine, which is incorporated into the DNA, caused chromosomal instability. While cell killing and first-division chromosomal rearrangements increased with increasing numbers of 125I decays, the frequency of chromosomal instability was independent of dose. Chromosomal instability could also be induced from incorporation of 125I-iododeoxyuridine without freezing the cells for accumulation of decays. This indicates that DNA double-strand breaks in frozen cells resulting from 125I decays failed to lead to instability. Incorporation of an 125I-labeled protein (125I-succinyl-concanavalin A), which was internalized into the cell and/or bound to the plasma membrane, neither caused chromosomal instability nor potentiated chromosomal instability induced by 125I-iododeoxyuridine. These results show that the target for radiation-induced chromosomal instability in these cells is the nucleus.

Multi-step production of a diphoton resonance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dobrescu, Bogdan A.; Fox, Patrick J.; Kearney, John

2017-04-24

Assuming that the mass peak at 750 GeV reported by the ATLAS and CMS Collaborations is due to a spin-0 particle that decays into two photons, we present two weakly-coupled renormalizable models that lead to different production mechanisms. In one model, a scalar particle produced through gluon fusion decays into the diphoton particle and a light, long-lived pseudoscalar. In another model, a $Z'$ boson produced from the annihilation of a strange-antistrange quark pair undergoes a cascade decay that leads to the diphoton particle and two sterile neutrinos. We show that various kinematic distributions may differentiate these models from the canonicalmore » model where the diphoton particle is directly produced in gluon fusion.« less

⁹⁹mTc pyrene derivative complex causes double-strand breaks in dsDNA mainly through cluster-mediated indirect effect in aqueous solution.

PubMed

Chung, Wei-Ju; Cui, Yujia; Huang, Feng-Yun J; Tu, Tzu-Hui; Yang, Tzu-Sen; Lo, Jem-Mau; Chiang, Chi-Shiun; Hsu, Ian C

2014-01-01

Radiation therapy for cancer patients works by ionizing damage to nuclear DNA, primarily by creating double-strand breaks (DSB). A major shortcoming of traditional radiation therapy is the set of side effect associated with its long-range interaction with nearby tissues. Low-energy Auger electrons have the advantage of an extremely short effective range, minimizing damage to healthy tissue. Consequently, the isotope ⁹⁹mTc, an Auger electron source, is currently being studied for its beneficial potential in cancer treatment. We examined the dose effect of a pyrene derivative ⁹⁹mTc complex on plasmid DNA by using gel electrophoresis in both aqueous and methanol solutions. In aqueous solutions, the average yield per decay for double-strand breaks is 0.011±0.005 at low dose range, decreasing to 0.0005±0.0003 in the presence of 1 M dimethyl sulfoxide (DMSO). The apparent yield per decay for single-strand breaks (SSB) is 0.04±0.02, decreasing to approximately a fifth with 1 M DMSO. In methanol, the average yield per decay of DSB is 0.54±0.06 and drops to undetectable levels in 2 M DMSO. The SSB yield per decay is 7.2±0.2, changing to 0.4±0.2 in the presence of 2 M DMSO. The 95% decrease in the yield of DSB in DMSO indicates that the main mechanism for DSB formation is through indirect effect, possibly by cooperative binding or clustering of intercalators. In the presence of non-radioactive ligands at a near saturation concentration, where radioactive Tc compounds do not form large clusters, the yield of SSB stays the same while the yield of DSB decreases to the value in DMSO. DSBs generated by ⁹⁹mTc conjugated to intercalators are primarily caused by indirect effects through clustering.

What is your Cosmic Connection to the Elements?

NASA Technical Reports Server (NTRS)

White, Nicholas E. (Technical Monitor); Lochner, James; Rohrbach, Gail; Cochrane, Kim

2003-01-01

This information and activity booklet describes the roles of the Big Bang, types of stars, supernovae, cosmic ray interactions, and radioactive decay in the formation of the elements. The booklet includes instructions for the following classroom activities, intended for students in Grades 9-12: Grandma's Apple Pie; Cosmic Shuffle; Nickel-odeon; Kinesthetic Big Bang; Elemental Haiku; Cosmic Ray Collisions; Cosmic Abundances; and What's Out There.

The data acquisition of OLGA II; An application of the PSI TANDEM system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jost, D.T.; Vermeulen, D.

1992-04-01

This paper describes the data acquisition of the on-line gas-chemistry apparatus (OLGA II). OLGA II is used to investigate the chemical behavior of volatile molecules of short lives isotopes. Special emphasis is given to the presentation of the PSI tandem data acquisition system used in these experiments. Time stamped event-by-event recording is used to follow radioactive decay chains.

Nuclear Explosion Monitoring Research and Development Roadmaps

DTIC Science & Technology

2010-09-01

environment, a radionuclide event is the release of radioactive atoms. Radionuclide sources include nuclear explosions, normal or anomalous reactor ...isotopes (e.g., potassium, uranium, and thorium and their decay products) and isotopes produced from the interactions of cosmic rays with the...and reactor emissions. For example, the IMS detected a pair of xenon isotopes at a Japanese station shortly after the 2009 DPRK event. The ratio of

Trace radioactive impurities in final construction materials for EXO-200

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leonard, D. S.; Auty, D. J.; Didberidze, T.

Here, we report results from a systematic measurement campaign conducted to identify low radioactivity materials for the construction of the EXO-200 double beta decay experiment. Partial results from this campaign have already been reported in a 2008 paper by the EXO collaboration. Here we release the remaining data, collected since 2007, to the public. The data reported were obtained using a variety of analytic techniques. The measurement sensitivities are among the best in the field. We concluded the construction of the EXO-200 detector and Phase-I data was taken from 2011 to 2014. The detector’s extremely low background implicitly verifies themore » measurements and the analysis assumptions made during construction and reported in this paper.« less

Trace radioactive impurities in final construction materials for EXO-200

DOE PAGES

Leonard, D. S.; Auty, D. J.; Didberidze, T.; ...

2017-05-01

Here, we report results from a systematic measurement campaign conducted to identify low radioactivity materials for the construction of the EXO-200 double beta decay experiment. Partial results from this campaign have already been reported in a 2008 paper by the EXO collaboration. Here we release the remaining data, collected since 2007, to the public. The data reported were obtained using a variety of analytic techniques. The measurement sensitivities are among the best in the field. We concluded the construction of the EXO-200 detector and Phase-I data was taken from 2011 to 2014. The detector’s extremely low background implicitly verifies themore » measurements and the analysis assumptions made during construction and reported in this paper.« less

Depleted uranium: an overview of its properties and health effects.

PubMed

Shawky, S

2002-01-01

There has been much debate about the use of depleted uranium in the Gulf War and its health effects on United States and European war veterans. However, studies on the impact of this radioactive substance on the residents of the surrounding Gulf region are far from adequate. Depleted uranium introduces large quantities of radioactive material that is hazardous to biological organisms, continues to decay for millennia and is able to travel tens of kilometres in air. If depleted uranium were used in the Gulf War, its impact on the health of people in the area would have been considerable. This review of depleted uranium--its origin, properties, uses and effects on the human environment and health--aims to trigger further research on this subject.

Fallout traces of the Fukushima NPP accident in southern West Siberia (Novosibirsk, Russia).

PubMed

Melgunov, M S; Pokhilenko, N P; Strakhovenko, V D; Sukhorukov, F V; Chuguevskii, A V

2012-05-01

The fallout of artificially produced radioactive isotopes has been recorded at a site in southern West Siberia (54°50'43.6″ N, 083°06'22.4″ E, Novosibirsk, Russia). The highest activities of (131)I, (134)Cs, and (136)Cs were found in fresh snow precipitated on 02 April 2011, at 0.83, 0.092, and 0.002 Bq L(-1) of meltwater, respectively. The (131)I/(134)Cs ratio decreased from 9.0 on 02 April to 1.2 on 27 April, which is consistent with the radioactive decay of (131)I. This fallout can only have originated from the accidental emission of Fukushima Nuclear Power Plant, Japan, in March 2011.

High-precision branching ratio measurement for the superallowed β+ emitter Ga62

NASA Astrophysics Data System (ADS)

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-08-01

A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8π spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the γ rays emitted following Gamow-Teller and nonanalog Fermi β+ decays of Ga62, and the SCEPTAR plastic scintillator array was used to detect the emitted β particles. Thirty γ rays were identified following Ga62 decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for Ga62, this branching ratio yields an ft value of 3074.3±1.1 s, making Ga62 among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected F tmacr value allows the large nuclear-structure-dependent correction for Ga62 decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A⩾62 superallowed decays.

An astrophysical engine that stores gravitational work as nuclear Coulomb energy

NASA Astrophysics Data System (ADS)

Clayton, Donald

2014-03-01

I describe supernovae gravity machines that store large internal nuclear Coulomb energy, 0.80Z2A- 1 / 3MeV per nucleus. Excess of it is returned later by electron capture and positron emission. Decay energy manifests as (1) observable gamma-ray lines (2) light curves of supernovae (3) chemical energy of free carbon dissociated from CO molecules (4) huge abundances of radiogenic daughters. I illustrate by rapid silicon burning, a natural epoch in SN II. Gravitational work produces the high temperatures that photoeject nucleons and alpha particles from heavy nuclei. These are retained by other nuclei to balance photoejection rates (quasiequilibrium). The abundance distribution adjusts slowly as remaining abundance of Z = N 28Si decomposes, so p, n, α recaptures hug the Z = N line. This occurs in milliseconds, too rapidly for weak decay to alter bulk Z/N ratio. The figure displays those quasiequilibrium abundances color-coded to their decays. Z = N = 2k nuclei having k < 11 are stable, whereas k > 10 are radioactive owing to excess Coulomb energy. Weak decays radiate that excess energy weeks later to fuel the four macroscopic energetic phenomena cited. How startling to think of the Coulomb nuclear force as storing cosmic energy and its weak decay releasing macroscopic activation to SNII.

β-delayed p-decay of proton-rich nuclei ^23Al and ^31Cl and explosive H-burning in novae

NASA Astrophysics Data System (ADS)

Trache, L.; Banu, A.; Hardy, J. C.; McCleskey, M.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Aysto, J.; Jokinen, A.; Saastamoinen, A.; Davinson, T.; Woods, P. J.; Achouri, L.; Roeder, B.

2008-10-01

We developed a technique to measure β-delayed proton-decay of proton-rich nuclei produced and separated with MARS at TAMU. In particular, we studied the decay of ^23Al and ^31Cl, both important for understanding explosive H-burning in novae. We have pulsed the beam, implanting the source nuclei moving at about 40 MeV/u in a thin Si strip detector, and then measured β-p and β-γ coincidences simultaneously. The states populated above the proton threshold in ^23Mg and ^31S, respectively, may proton decay. They are resonances in the reaction ^22Na(p,γ)^23Mg (crucial for the depletion of ^22Na in ONe novae) and in ^30P(p,γ)^31S (critical point in explosive H-burning in novae), but the protons emitted have very low energies, starting at about 200 keV, an experimental challenge. The setup and the results are described. The β-decay schemes were established for both nuclei, and IAS identified. The technique has shown a remarkable selectivity to β-delayed charged particle emission and shown to work even at radioactive beam rates of a few pps, for rare isotopes with lifetimes as low as 10s msec.

Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farmer, J.C.; Van Konynenburg, R.A.; McCright, R.D.

1988-04-01

Three iron- to nickel-based austenitic alloys (Types 304L and 316L stainless steels and Alloy 825) are being considered as candidate materials for the fabrication of high-level radioactive-waste containers. Waste will include fuel assemblies from reactors as well as high-level waste in borosilicate glass forms, and will be sent to the prospective repository at Yucca Mountain, Nevada. The decay of radionuclides in the repository will result in the generation of substantial heat and in fluences of gamma radiation. Container materials may undergo any of several modes of degradation in this environment, including atmospheric oxidation; uniform aqueous phase corrosion; pitting; crevice corrosion;more » sensitization and intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This report is an analysis of data relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of the three austenitic candidate alloys. The candidates are compared in terms of their susceptibilities to these forms of corrosion. Although all three candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these types of localized corrosion (LC); such resistance is important because pits can penetrate the metal and serve as crack initiation sites. Both Types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented in Alloy 825 under comparable conditions. Gamma radiation has been found to enhance SCC in Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while the effects of microbiologically induced corrosion have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. 211 refs., 49 figs., 10 tabs.« less

Neutron counter based on beryllium activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bienkowska, B.; Prokopowicz, R.; Kaczmarczyk, J.

2014-08-21

The fusion reaction occurring in DD plasma is followed by emission of 2.45 MeV neutrons, which carry out information about fusion reaction rate and plasma parameters and properties as well. Neutron activation of beryllium has been chosen for detection of DD fusion neutrons. The cross-section for reaction {sup 9}Be(n, α){sup 6}He has a useful threshold near 1 MeV, which means that undesirable multiple-scattered neutrons do not undergo that reaction and therefore are not recorded. The product of the reaction, {sup 6}He, decays with half-life T{sub 1/2} = 0.807 s emitting β{sup −} particles which are easy to detect. Large areamore » gas sealed proportional detector has been chosen as a counter of β–particles leaving activated beryllium plate. The plate with optimized dimensions adjoins the proportional counter entrance window. Such set-up is also equipped with appropriate electronic components and forms beryllium neutron activation counter. The neutron flux density on beryllium plate can be determined from the number of counts. The proper calibration procedure needs to be performed, therefore, to establish such relation. The measurements with the use of known β–source have been done. In order to determine the detector response function such experiment have been modeled by means of MCNP5–the Monte Carlo transport code. It allowed proper application of the results of transport calculations of β{sup −} particles emitted from radioactive {sup 6}He and reaching proportional detector active volume. In order to test the counter system and measuring procedure a number of experiments have been performed on PF devices. The experimental conditions have been simulated by means of MCNP5. The correctness of simulation outcome have been proved by measurements with known radioactive neutron source. The results of the DD fusion neutron measurements have been compared with other neutron diagnostics.« less

Movement of a tritium plume in shallow groundwater at a legacy low-level radioactive waste disposal site in eastern Australia.

PubMed

Hughes, C E; Cendón, D I; Harrison, J J; Hankin, S I; Johansen, M P; Payne, T E; Vine, M; Collins, R N; Hoffmann, E L; Loosz, T

2011-10-01

Between 1960 and 1968 low-level radioactive waste was buried in a series of shallow trenches near the Lucas Heights facility, south of Sydney, Australia. Groundwater monitoring carried out since the mid 1970s indicates that with the exception of tritium, no radioactivity above typical background levels has been detected outside the immediate vicinity of the trenches. The maximum tritium level detected in ground water was 390 kBq/L and the median value was 5400 Bq/L, decay corrected to the time of disposal. Since 1968, a plume of tritiated water has migrated from the disposal trenches and extends at least 100 m from the source area. Tritium in rainfall is negligible, however leachate from an adjacent and fill represents a significant additional tritium source. Study data indicate variation in concentration levels and plume distribution in response to wet and dry climatic periods and have been used to determine pathways for tritium migration through the subsurface.

Atomic mass measurements with radioactive beams and/or targets: Where to start

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haustein, P.E.

1989-01-01

Radioactive beams or radioactive targets (or both) can significantly increase the yields of exotic isotopes, allowing studies to be performed in regions which are currently inaccessible. An important goal to pursue with these exotic species is a broad program of nuclidic mass measurements. This is motivated by the observation that mass model predictions generally diverge from one another in regions far from beta-decay stability where well measured masses are sparse or nonexistent. Stringent tests of mass models are therefore possible and these can highlight important features in the mass models that affect the quality of their short-range and long-range extrapolationmore » properties. Selection of systems to study can be guided, in part, by a desire to probe those regions where distinctions among mass models are most apparent and where exotic isotope yields will be optimal. Several examples will be presented to highlight future opportunities in this area. 10 refs., 5 figs.« less

Numerical modeling of subsurface radioactive solute transport from waste seepage ponds at the Idaho National Engineering Laboratory

USGS Publications Warehouse

Robertson, John B.

1976-01-01

Aqueous chemical and low-level radioactive effluents have been disposed to seepage ponds since 1952 at the Idaho National Engineering Laboratory. The solutions percolate toward the Snake River Plain aquifer (135 m below) through interlayered basalts and unconsolidated sediments and an extensive zone of ground water perched on a sedimentary layer about 40 m beneath the ponds. A three-segment numerical model was developed to simulate the system, including effects of convection, hydrodynamic dispersion, radioactive decay, and adsorption. Simulated hydraulics and solute migration patterns for all segments agree adequately with the available field data. The model can be used to project subsurface distributions of waste solutes under a variety of assumed conditions for the future. Although chloride and tritium reached the aquifer several years ago, the model analysis suggests that the more easily sorbed solutes, such as cesium-137 and strontium-90, would not reach the aquifer in detectable concentrations within 150 years for the conditions assumed. (Woodard-USGS)

Enhancement of low-energy electron emission in 2D radioactive films

NASA Astrophysics Data System (ADS)

Pronschinske, Alex; Pedevilla, Philipp; Murphy, Colin J.; Lewis, Emily A.; Lucci, Felicia R.; Brown, Garth; Pappas, George; Michaelides, Angelos; Sykes, E. Charles H.

2015-09-01

High-energy radiation has been used for decades; however, the role of low-energy electrons created during irradiation has only recently begun to be appreciated. Low-energy electrons are the most important component of radiation damage in biological environments because they have subcellular ranges, interact destructively with chemical bonds, and are the most abundant product of ionizing particles in tissue. However, methods for generating them locally without external stimulation do not exist. Here, we synthesize one-atom-thick films of the radioactive isotope 125I on gold that are stable under ambient conditions. Scanning tunnelling microscopy, supported by electronic structure simulations, allows us to directly observe nuclear transmutation of individual 125I atoms into 125Te, and explain the surprising stability of the 2D film as it underwent radioactive decay. The metal interface geometry induces a 600% amplification of low-energy electron emission (<10 eV; ref. ) compared with atomic 125I. This enhancement of biologically active low-energy electrons might offer a new direction for highly targeted nanoparticle therapies.

Correlation-study about the ambient dose rate and the weather conditions

NASA Astrophysics Data System (ADS)

Furuya, Masato; Hatano, Yuko; Aoyama, Tomoo; Igarashi, Yasuhito; Kita, Kazuyuki; Ishizuka, Masahide

2016-04-01

The long-term radiation risks are believed to be heavily affected by the resuspension process. We therefore focus on the surface-atmosphere exchange process of released radioactive materials in this study. Radioactive materials were deposited on the soil and float in the air, and such complicated process are influenced by the weather conditions deeply. We need to reveal the correlation between the weather conditions and the ambient dose rate. In this study, we study the correlation between the weather conditions and the ambient dose rate with the correction of the decrease due to the radioactive decay. We found that there is a negative correlation between the ambient dose rate and the soil water content by the correlation coefficient. Using this result, we reconstruct the ambient dose rate from the weather conditions by the multiple regression analysis and found that the reconstructed data agree with the observation very well. Using Kalman filter, which can be sequentially updates the state estimate, we obtained such a good agreement.

Low-Level Waste Forum notes and summary reports for 1994. Volume 9, Number 3, May-June 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1994-06-01

This issue includes the following articles: Vermont ratifies Texas compact; Pennsylvania study on rates of decay for classes of low-level radioactive waste; South Carolina legislature adjourns without extending access to Barnwell for out-of-region generators; Southeast Compact Commission authorizes payments for facility development, also votes on petitions, access contracts; storage of low-level radioactive waste at Rancho Seco removed from consideration; plutonium estimates for Ward Valley, California; judgment issued in Ward Valley lawsuits; Central Midwest Commission questions court`s jurisdiction over surcharge rebates litigation; Supreme Court decides commerce clause case involving solid waste; parties voluntarily dismiss Envirocare case; appellate court affirms dismissal ofmore » suit against Central Commission; LLW Forum mixed waste working group meets; US EPA Office of Radiation and Indoor Air rulemakings; EPA issues draft radiation site cleanup regulation; EPA extends mixed waste enforcement moratorium; and NRC denies petition to amend low-level radioactive waste classification regulations.« less

Purification of lanthanides for double beta decay experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polischuk, O. G.; Barabash, A. S.; Belli, P.

2013-08-08

There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain {sup 238}U, {sup 226}Ra and {sup 232,228}Th typically on the level of ∼ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO{sub 2}, Nd{sub 2}O{sub 3} and Gd{sub 2}O{sub 3}. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxidemore » by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R and D of the methods to remove the pollutions with improved efficiency is in progress.« less

Radiochemistry in the twenty-first century: Strenghts, weaknesses, opportunities and threats

NASA Astrophysics Data System (ADS)

de Goeij, J. J. M.

2003-01-01

Strengths, weaknesses, opportunities and threats of radiochemistry and associated nuclear chemistry are discussed. For that purpose radiochemistry is subdivided into three categories. The first category covers fundamental aspects, e.g. nuclear reaction cross-sections, production routes with associated yields and radionuclidic impurities, decay schemes, radiochemical separations, recoil and hot-atom chemistry, isotope effects and fractionation, and interaction of radiation with matter and detection. The second category covers topics where radioactivity is inextricably involved, e.g. the nuclear fuel cycle, very heavy elements and other actinides, primordial and cosmogenic radioactivity, and radionuclide techniques for dating. The third category involves radioactivity as essential part of a technique. On one hand radioactivity is used here as source of ionising radiation for food conservation, polymerisation of plastics, sterilisation, radiotherapy and pain palliation. On the other hand it is used to get information on systems and materials, via radiotracer methods and nuclear activation techniques. In particular the latter field is experiencing strong competition with other, non-nuclear methods. In this frame it is indicated what is required to achieve a situation where nuclear analytical techniques may successfully be exploited to the full extent of their potentials, particularly in providing valuable and sometimes unique information.

R-process experiments with the Advanced Implantation Detector Array

NASA Astrophysics Data System (ADS)

Estrade, Alfredo; Griffin, Chris; Davinson, Tom; Bruno, Carlo; Hall, Oscar; Liu, Zhong; Woods, Phil; Coleman-Smith, Patrick; Labiche, Marc; Lazarus, Ian; Pucknell, Victor; Simpson, John; Harkness-Brennan, Laura; Page, Robert; Kiss, Gabor; Liu, Jiajiang; Matsui, Keishi; Nishimura, Shunji; Phong, Vi; Lorusso, Giuseppe; Montes, Fernando; Nepal, Neerajan; Briken Collaboration; Ribf106 Experiment Team

2017-09-01

Decay properties of neutron rich isotopes, such as half-lives and β-delayed neutron emission probabilities, are an important input for astrophysical models of the r-process. A new generation of fragmentation beam facilities has made it possible to access large regions of the nuclear chart that are close to the path of the r-process for some astrophysical models. The Advanced Implantation Detector Array (AIDA) is a segmented active-stopper detector designed for decay experiments with fast ion beams, which was recently commissioned at the Radioactive Ion Beam Factory in RIKEN, Japan. In this presentation we describe the main characteristics of AIDA, and present preliminary results of the first experiments in the region of neutron-rich selenium isotopes and along the N=82 shell closure.

Half-life of 51Mn

NASA Astrophysics Data System (ADS)

Graves, Stephen A.; Ellison, Paul A.; Valdovinos, Hector F.; Barnhart, Todd E.; Nickles, Robert J.; Engle, Jonathan W.

2017-07-01

The half-life of 51Mn was measured by serial gamma spectrometry of the 511-keV annihilation photon following decay by β+ emission. Data were collected every 100 seconds for 100,000-230,000 seconds within each measurement (n =4 ). The 511-keV incidence rate was calculated from the 511-keV spectral peak area and count duration, corrected for detector dead time and radioactive decay. Least-squares regression analysis was used to determine the half-life of 51Mn while accounting for the presence of background contaminants, notably 55Co. The result was 45.59 ±0.07 min, which is the highest precision measurement to date and disagrees with the current Nuclear Data Sheets value by over 6 σ .

Method for radioactivity monitoring

DOEpatents

Umbarger, C. John; Cowder, Leo R.

1976-10-26

The disclosure relates to a method for analyzing uranium and/or thorium contents of liquid effluents preferably utilizing a sample containing counting chamber. Basically, 185.7-keV gamma rays following .sup.235 U alpha decay to .sup.231 Th which indicate .sup.235 U content and a 63-keV gamma ray doublet found in the nucleus of .sup.234 Pa, a granddaughter of .sup.238 U, are monitored and the ratio thereof taken to derive uranium content and isotopic enrichment .sup.235 U/.sup.235 U + .sup.238 U) in the liquid effluent. Thorium content is determined by monitoring the intensity of 238-keV gamma rays from the nucleus of .sup.212 Bi in the decay chain of .sup.232 Th.

Mathematical Investigation of Gamma Ray and Neutron Absorption Grid Patterns for Homeland Defense Related Fourier Imaging Systems

NASA Technical Reports Server (NTRS)

Boccio, Dona

2003-01-01

Terrorist suitcase nuclear devices typically using converted Soviet tactical nuclear warheads contain several kilograms of plutonium. This quantity of plutonium emits a significant number of gamma rays and neutrons as it undergoes radioactive decay. These gamma rays and neutrons normally penetrate ordinary matter to a significant distance. Unfortunately this penetrating quality of the radiation makes imaging with classical optics impractical. However, this radiation signature emitted by the nuclear source may be sufficient to be imaged from low-flying aerial platforms carrying Fourier imaging systems. The Fourier imaging system uses a pair of co-aligned absorption grids to measure a selected range of spatial frequencies from an object. These grids typically measure the spatial frequency in only one direction at a time. A grid pair that looks in all directions simultaneously would be an improvement over existing technology. A number of grid pairs governed by various parameters were investigated to solve this problem. By examining numerous configurations, it became apparent that an appropriate spiral pattern could be made to work. A set of equations was found to describe a grid pattern that produces straight fringes. Straight fringes represent a Fourier transform of a point source at infinity. An inverse Fourier transform of this fringe pattern would provide an accurate image (location and intensity) of a point source.

Exploring the hidden interior of the Earth with directional neutrino measurements

DOE PAGES

Leyton, Michael; Dye, Stephen; Monroe, Jocelyn

2017-07-10

Roughly 40% of the Earth’s total heat flow is powered by radioactive decays in the crust and mantle. Geo-neutrinos produced by these decays provide important clues about the origin, formation and thermal evolution of our planet, as well as the composition of its interior. Previous measurements of geo-neutrinos have all relied on the detection of inverse beta decay reactions, which are insensitive to the contribution from potassium and do not provide model-independent information about the spatial distribution of geo-neutrino sources within the Earth. Here in this paper we present a method for measuring previously unresolved components of Earth’s radiogenic heatingmore » using neutrino-electron elastic scattering and low-background, direction-sensitive tracking detectors.We calculate the exposures needed to probe various contributions to the total geo-neutrino flux, specifically those associated to potassium, the mantle and the core. The measurements proposed here chart a course for pioneering exploration of the veiled inner workings of the Earth.« less

Exploring the hidden interior of the Earth with directional neutrino measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leyton, Michael; Dye, Stephen; Monroe, Jocelyn

Roughly 40% of the Earth’s total heat flow is powered by radioactive decays in the crust and mantle. Geo-neutrinos produced by these decays provide important clues about the origin, formation and thermal evolution of our planet, as well as the composition of its interior. Previous measurements of geo-neutrinos have all relied on the detection of inverse beta decay reactions, which are insensitive to the contribution from potassium and do not provide model-independent information about the spatial distribution of geo-neutrino sources within the Earth. Here in this paper we present a method for measuring previously unresolved components of Earth’s radiogenic heatingmore » using neutrino-electron elastic scattering and low-background, direction-sensitive tracking detectors.We calculate the exposures needed to probe various contributions to the total geo-neutrino flux, specifically those associated to potassium, the mantle and the core. The measurements proposed here chart a course for pioneering exploration of the veiled inner workings of the Earth.« less

Exploring the hidden interior of the Earth with directional neutrino measurements

PubMed Central

Leyton, Michael; Dye, Stephen; Monroe, Jocelyn

2017-01-01

Roughly 40% of the Earth’s total heat flow is powered by radioactive decays in the crust and mantle. Geo-neutrinos produced by these decays provide important clues about the origin, formation and thermal evolution of our planet, as well as the composition of its interior. Previous measurements of geo-neutrinos have all relied on the detection of inverse beta decay reactions, which are insensitive to the contribution from potassium and do not provide model-independent information about the spatial distribution of geo-neutrino sources within the Earth. Here we present a method for measuring previously unresolved components of Earth’s radiogenic heating using neutrino-electron elastic scattering and low-background, direction-sensitive tracking detectors. We calculate the exposures needed to probe various contributions to the total geo-neutrino flux, specifically those associated to potassium, the mantle and the core. The measurements proposed here chart a course for pioneering exploration of the veiled inner workings of the Earth. PMID:28691700

An innovative technique for the investigation of the 4-fold forbidden beta-decay of 50V

NASA Astrophysics Data System (ADS)

Pattavina, L.; Laubenstein, M.; Nagorny, S. S.; Nisi, S.; Pagnanini, L.; Pirro, S.; Rusconi, C.; Schäffner, K.

2018-05-01

For the first time a Vanadium-based crystal was operated as cryogenic particle detector. The scintillating low temperature calorimetric technique was used for the characterization of a 22g YVO4 crystal aiming at the investigation of the 4-fold forbidden non-unique β- decay of 50V. The excellent bolometric performance of the compound together with high light output of the crystal make it an outstanding technique for the study of such elusive rate process. The internal radioactive contaminations of the crystal are also investigated showing that an improvement on the current status of material selection and purification are needed, 235/238U and 232Th are measured at the level of 28mBq/kg, 1.3 Bq/kg and 28m Bq/kg, respectively. In this work, we also discuss a future upgrade of the experimental set-up which may pave the road for the detection of the rare 50V β- decay.

Decay Pattern of Pygmy States Observed in Neutron-Rich Ne26

NASA Astrophysics Data System (ADS)

Gibelin, J.; Beaumel, D.; Motobayashi, T.; Blumenfeld, Y.; Aoi, N.; Baba, H.; Elekes, Z.; Fortier, S.; Frascaria, N.; Fukuda, N.; Gomi, T.; Ishikawa, K.; Kondo, Y.; Kubo, T.; Lima, V.; Nakamura, T.; Saito, A.; Satou, Y.; Scarpaci, J.-A.; Takeshita, E.; Takeuchi, S.; Teranishi, T.; Togano, Y.; Vinodkumar, A. M.; Yanagisawa, Y.; Yoshida, K.

2008-11-01

Coulomb excitation of the exotic neutron-rich nucleus Ne26 on a Pb208 target was measured at 58MeV/u in order to search for low-lying E1 strength above the neutron emission threshold. This radioactive beam experiment was carried out at the RIKEN Accelerator Research Facility. Using the invariant mass method in the Ne25+n channel, we observe a sizable amount of E1 strength between 6 and 10 MeV excitation energy. By performing a multipole decomposition of the differential cross section, a reduced dipole transition probability of B(E1)=0.49±0.16e2fm2 is deduced, corresponding to 4.9±1.6% of the Thomas-Reiche-Kuhn sum rule. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is measured. The extracted decay pattern is not consistent with several mean-field theory descriptions of the pygmy states.

Temporary ovarian failure in thyroid cancer patients after thyroid remnant ablation with radioactive iodine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raymond, J.P.; Izembart, M.; Marliac, V.

We studied ovarian function retrospectively in 66 women who had regular menstrual cycles before undergoing complete thyroidectomy for differentiated thyroid cancer and subsequent thyroid remnant ablation with /sup 131/I. Eighteen women developed temporary amenorrhea accompanied by increased serum gonadotropin concentrations during the first year after /sup 131/I therapy. No correlation was found between the radioactive iodine dose absorbed, thyroid uptake before treatment, oral contraceptive use, or thyroid autoimmunity. Only age was a determining factor, with the older women being the most affected. We conclude that radioiodine ablation therapy is followed by transient ovarian failure, especially in older women.

Nuclear Weapons: Comprehensive Test Ban Treaty

DTIC Science & Technology

2006-07-10

continued...) The complex could contain explosions up to 500 pounds of explosive and associated plutonium. Another SCE, “ Unicorn ,” is to be conducted...scheduled for FY2006, as noted below. SCEs try to determine if radioactive decay of aged plutonium would degrade weapon performance. Several SCEs...Richardson called SCEs “a key part of our scientific program to provide new tools and data that assess age -related complications and maintain the reliability

Detection of radon emission at the edges of lunar maria with the Apollo alpha-particle spectrometer

NASA Technical Reports Server (NTRS)

Gorenstein, P.; Golub, L.; Bjorkholm, P.

1974-01-01

The distribution of radioactive polonium-210, a decay product of radon-222, shows enhanced concentrations at the edges of lunar maria. Enhancements are seen at the edges of Mare Fecunditatis, Mare Crisium, Mare Smythii, Mare Tranquillitatis, Mare Nubium, Mare Cognitum, and Oceanus Procellarum. The observation is indicative of the transient emission of radon gas from the perimeters of lunar maria.

Detection of radon emission at the edges of lunar maria with the apollo alpha-particle spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorenstein, P.; Golub, L.; Bjorkholm, P.

1974-02-01

The distribution of radioactive /sup 210/Po, a decay product of /sup 222/ Rn, shows enhanced concentrations at the edges of lunar maria. Enhancements are seen at the edges of Mare Fecunditatis, Mare Crisium, Mare Smythii, Mare Tranquillitatis, Mare Nubium, Mare Cognitum, and Oceanus Procellarum. The observation is indicative of the transient emission of radon gas from the perimeters of lunar maria. (auth)

Sediment data for computations of deposition rates in the tidal Potomac system, Maryland and Virginia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glenn, J.L.; Martin, E.A.; Rice, C.A.

1986-01-01

Sixty-two cores ranging in length from 33 to 1,002 cm were collected from the tidal Potomac system and from selected tributaries downstream from the local head-of-tides between June 1978 and July 1981. Segments from selected depths below the sediment surface have been analyzed for a variety of constituents, including lead-210, trace metals, nutrients, and particle size. The core sites were positioned throughout the hydrologic divisions and geomorphic units of the tidal Potomac system and in water depths ranging from 1 to 30 cm. Alpha counting methods were used to determine the polonium-210 radioactivity and secular equilibrium was assumed between lead-210more » and polonium-210. The alpha decay of polonium-210 provides a measure of the lead-210 radioactivity of the lead-210 produced by in-situ decay of radium-226 in the sediment column and the lead-210 from external sources. Only the unsupported lead-210 was used in computations of the deposition rate. The background level of lead-210 in tidal Potomac system sediment cores usually is based on in-situ measurements of total lead-210 at depths below which no unsupported lead-210 is believed to be present, and the lead-210 concentrations are relatively constant. 6 refs., 3 figs., 1 tab.« less

[The assessment of radionuclide contamination and toxicity of soils sampled from "experimental field" site of Semipalatinsk nuclear test site].

PubMed

Evseeva, T I; Maĭstrenko, T A; Belykh, E S; Geras'kin, S A; Kriazheva, E Iu

2009-01-01

Large-scale maps (1:25000) of soil contamination with radionuclides, lateral distribution of 137Cs, 90Sr, Fe and Mn water-soluble compounds and soil toxicity in "Experimental field" site of Semipalatinsk nuclear test site were charted. At present soils from studied site (4 km2) according to basic sanitary standards of radiation safety adopted in Russian Federation (OSPORB) do not attributed to radioactive wastes with respect to data on artificial radionuclide concentration, but they do in compliance with IAEA safety guide. The soils studied can not be released from regulatory control due to radioactive decay of 137Cs and 90Sr and accumulation-decay of 241Am up to 2106 year according to IAEA concept of exclusion, exemption and clearance. Data on bioassay "increase of Chlorella vulgaris Beijer biomass production in aqueous extract from soils" show that the largest part of soils from the studied site (74%) belongs to stimulating or insignificantly influencing on the algae reproduction due to water-soluble compounds effect. Toxic soils occupy 26% of the territory. The main factors effecting the algae reproduction in the aqueous extracts from soil are Fe concentration and 90Sr specific activity: 90Sr inhibits but Fe stimulates algae biomass production.

β Decay as a Probe of Explosive Nucleosynthesis in Classical Novae

NASA Astrophysics Data System (ADS)

Wrede, C.; Bennett, M. B.; Liddick, S. N.; Bardayan, D. W.; Bowe, A.; Brown, B. A.; Chen, A. A.; Chipps, K. A.; Cooper, N.; Fry, C.; Glassman, B.; Irvine, D.; José, J.; Langer, C.; Larson, N.; McNeice, E. I.; Meisel, Z.; Montes, F.; Naqvi, F.; Pain, S. D.; O'Malley, P.; Ortez, R.; Ong, W.; Pereira, J.; Pérez-Loureiro, D.; Prokop, C.; Quaglia, J.; Quinn, S.; Santia, M.; Schatz, H.; Schwartz, S. B.; Simon, A.; Shanab, S.; Spyrou, A.; Suchyta, S.; Thiagalingam, E.; Thompson, P.; Walters, M.

Classical novae are common thermonuclear explosions in the Milky Way galaxy, occurring on the surfaces of white-dwarf stars that are accreting hydrogen-rich material from companion stars. Nucleosynthesis in classical novae depends on radiative proton-capture reaction rates on radioactive nuclides. Many of these reactions cannot be measured directly at current accelerator facilities due to the lack of intense, high-quality, radioactive-ion beams at the relevant energies. Since most of these reactions proceed via resonant capture, their rates can be determined indirectly by measuring the properties of the resonances. At the National Superconducting Cyclotron Laboratory, we have used the β-delayed γ decays of 26P and 31Cl to populate resonances in 26Si and 31S and study the radiative proton captures on 25Al and 30P, respectively. These were two out of the three most important nuclear-physics uncertainties associated with the observable products of nova nucleosynthesis. The 26P experiment has enabled a more accurate estimate of the nova contribution to the long-lived Galactic 26Al detected with γ-ray telescopes. The 31Cl experiment, currently under analysis, will calibrate potential nova thermometers and mixing meters based on elemental abundance ratios, and facilitate the identification of pre-solar nova grain candidates found in primitive meteorites based on isotopic ratios.

Feasibility study of SiGHT: a novel ultra low background photosensor for low temperature operation

DOE PAGES

Wang, Y.; Fan, A.; Fiorillo, G.; ...

2017-02-27

Rare event search experiments, such as those searching for dark matter and observations of neutrinoless double beta decay, require ultra low levels of radioactive background for unmistakable identification. In order to reduce the radioactive background of detectors used in these types of event searches, low background photosensors are required, as the physical size of these detectors become increasing larger, and hence the number of such photosensors used also increases rapidly. Considering that most dark matter and neutrinoless double beta decay experiments are turning towards using noble liquids as the target choice, liquid xenon and liquid argon for instance, photosensors thatmore » can work well at cryogenic temperatures are required, 165 K and 87 K for liquid xenon and liquid argon, respectively. The Silicon Geiger Hybrid Tube (SiGHT) is a novel photosensor designed specifically for use in ultra low background experiments operating at cryogenic temperatures. It is based on the proven photocathode plus silicon photomultiplier (SiPM) hybrid technology and consists of very few other, but also ultra radio-pure, materials like fused silica and silicon for the SiPM. Lastly, the introduction of the SiGHT concept, as well as a feasibility study for its production, is reported in this article.« less

PLANTS AS BIO-MONITORS FOR 137CS, 238PU, 239, 240PU AND 40K AT THE SAVANNAH RIVER SITE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caldwell, E.; Duff, M.; Ferguson, C.

2010-12-16

The nuclear fuel cycle generates a considerable amount of radioactive waste, which often includes nuclear fission products, such as strontium-90 ({sup 90}Sr) and cesium-137 ({sup 137}Cs), and actinides such as uranium (U) and plutonium (Pu). When released into the environment, large quantities of these radionuclides can present considerable problems to man and biota due to their radioactive nature and, in some cases as with the actinides, their chemical toxicity. Radionuclides are expected to decay at a known rate. Yet, research has shown the rate of elimination from an ecosystem to differ from the decay rate due to physical, chemical andmore » biological processes that remove the contaminant or reduce its biological availability. Knowledge regarding the rate by which a contaminant is eliminated from an ecosystem (ecological half-life) is important for evaluating the duration and potential severity of risk. To better understand a contaminants impact on an environment, consideration should be given to plants. As primary producers, they represent an important mode of contamination transfer from sediments and soils into the food chain. Contaminants that are chemically and/or physically sequestered in a media are less likely to be bio-available to plants and therefore an ecosystem.« less

The search for majoron emission in xenon-136 and two-neutrino double-beta decay of xenon-134 with the enriched xenon observatory

NASA Astrophysics Data System (ADS)

Walton, Josiah

Despite neutrino oscillation experiments firmly establishing neutrinos have non-zero mass, the absolute mass scale is unknown. Moreover, it's unknown whether the neutrino is distinguishable from its antiparticle. The most promising approach for measuring the neutrino mass scale and answering the issue of neutrino-antineutrino distinguishability is by searching for neutrinoless double-beta decay, a very rare theorized process not allowed under the current theoretical framework of particle physics. Positive observation of neutrinoless double-beta decay would usher in a revolution in particle physics, since it would determine the neutrino mass scale, establish that neutrinos and antineutrinos are indistinguishable, and that the particle physics conservation law of total lepton number is violated in nature. The latter two consequences are particularly salient, as they lead to potential explanations of neutrino mass generation and the observed large asymmetry of matter over antimatter in the universe. The Enriched Xenon Observatory (EXO-200) is an international collaboration searching for the neutrinoless double-beta decay of the isotope 136 Xe. EXO-200 operates a unique world-class low-radioactivity detector containing 110 kg of liquified xenon isotopically enriched to 80.6% in 136Xe. Recently, EXO-200 published the most precise two-neutrino double-beta decay half-life ever measured and one of the strongest limits on the half-life of the neutrinoless double-beta decay mode of 136Xe. This work presents an improved experimental search for the majoron-mediated neutrinoless double-beta decay modes of 136Xe and a novel search for the yet unobserved two neutrino double-beta decay of 134Xe.

Radon and thoron inhalation doses in dwellings with earthen architecture: Comparison of measurement methods.

PubMed

Meisenberg, Oliver; Mishra, Rosaline; Joshi, Manish; Gierl, Stefanie; Rout, Rajeswari; Guo, Lu; Agarwal, Tarun; Kanse, Sandeep; Irlinger, Josef; Sapra, Balvinder K; Tschiersch, Jochen

2017-02-01

The radioactive noble gas radon ( 222 Rn) and its decay products have been considered a health risk in the indoor environment for many years because of their contribution to the radiation dose of the lungs. The radioisotope thoron ( 220 Rn) and its decay products came into focus of being a health risk only recently. The reason for this is its short half-life, so only building material can become a significant source for indoor thoron. In this study, dwellings with earthen architecture were investigated with different independent measurement techniques in order to determine appropriate methods for reliable dose assessment of the dwellers. While for radon dose assessment, radon gas measurement and the assumption of a common indoor equilibrium factor often are sufficient, thoron gas has proven to be an unreliable surrogate for a direct measurement of thoron decay products. Active/time-resolved but also passive/integrating measurements of the total concentration of thoron decay products demonstrated being precise and efficient methods for determining the exposure and inhalation dose from thoron and its decay products. Exhalation rate measurements are a useful method for a rough dose estimate only if the exhalation rate is homogeneous throughout the house. Before the construction of a building in-vitro exhalation rate measurements on the building material can yield information about the exposure that is to be expected. Determining the unattached fraction of radon decay products and even more of thoron decay products leads to only a slightly better precision; this confirms the relative unimportance of the unattached thoron decay products due to their low concentration. The results of this study thereby give advice on the proper measurement method in similar exposure situations. Copyright © 2017 Elsevier B.V. All rights reserved.

First-order reactant in homogeneous turbulence before the final period of decay. [contaminant fluctuations in chemical reaction

NASA Technical Reports Server (NTRS)

Kumar, P.; Patel, S. R.

1974-01-01

A method is described for studying theoretically the concentration fluctuations of a dilute contaminate undergoing a first-order chemical reaction. The method is based on Deissler's (1958) theory for homogeneous turbulence for times before the final period, and it follows the approach used by Loeffler and Deissler (1961) to study temperature fluctuations in homogeneous turbulence. Four-point correlation equations are obtained; it is assumed that terms containing fifth-order correlation are very small in comparison with those containing fourth-order correlations, and can therefore be neglected. A spectrum equation is obtained in a form which can be solved numerically, yielding the decay law for the concentration fluctuations in homogeneous turbulence for the period much before the final period of decay.

Isotopes in the Garden a Narrative of the Atomic Age and its Legacy in the Global Landscape

NASA Astrophysics Data System (ADS)

Young, Thomas Joseph

The following is a narrative, which explores the age of nuclear enlightenment--or the Atomic Age--and its physical ramifications within the landscape. This era--starting with the discovery of radioactivity in 1898 and continuing through today--began with a belief in progress towards a brighter tomorrow, but ended in destructive actions that will continue to decay within our soils and bones for millions of years into the future. Following the stories of key people, such as Marie Curie, Robert Oppenheimer, and Edward Teller, this thesis tells a story, which even though it is historically recent, it is unknown to people of the millennial generation--those born from the early 1980s through the early 2000s. To tell the story, the thesis draws upon science, politics, history, and pop-culture and employs a specific representation technique that draws from mid-twentieth century movie animation. Based upon the author's own experiences, the thesis argues that the millennial generation is less informed of, less motivated by, or less interested in the legacies of the Atomic Age. Ultimately, the thesis seeks to remedy this detachment from this historically relevant narrative. To do this, the thesis explores the physical ramifications of nuclear ingenuity over the last 120 years, which has resulted in the unintentional and global spread of radioactive isotopes via atmospheric nuclear weapons testing and nuclear meltdowns. This radioactive debris has become embedded within our earth's crust, plants, animals, and bodies, where it will decay for millions of years into the future. This paper hopes to engage the readers with this reality and transform their perspective of this age from a distant past to an imminent present and future.

Natural radioactivity in underground water from the Outer Carpathians in Poland with the use of nuclear spectrometry techniques.

PubMed

Walencik, A; Kozłowska, B; Dorda, J; Zipper, W

2010-01-01

The investigations of natural radioactivity in underground mineral water and spring water in health resorts in the Outer Carpathians were performed. Samples from 40 water springs were collected 3-4 times over a period of 10 years (1997-2007). In order to obtain necessary data, two different nuclear spectrometry techniques were applied: WinSpectral alphabeta 1414 liquid scintillation counter from Wallac and alpha-spectrometer 7401 VR from Canberra-Packard, USA with the silicon surface barrier detector. The activity concentrations of (222)Rn in the investigated samples varied from below 1 to 50 Bq/l. For radium isotopes the concentrations were in a range from below 10 to 490 mBq/l for (226)Ra and from 29 to 397 mBq/l for (228)Ra. The highest concentrations for both radium isotopes were obtained for medicinal water Zuber III from Krynica spa. The activity concentrations for uranium isotopes varied from below 0.5 to 16 mBq/l for (238)U and from below 0.5 to 162 mBq/l for (234)U with the highest values obtained for water Zuber IV. The highest annual effective dose arising from mainly radium isotopes was obtained for Zuber III water and was equal to 75 microSv/yr. Additionally, the annual effective doses due to (222)Rn consumed with water were also estimated. The isotopic ratios between isotopes originating from the same decay chain ((234)U/(238)U, (226)Ra/(238)U) and from different radioactive decay chains ((226)Ra/(228)Ra) were determined. The correlations between different isotopes were presented. Copyright 2009 Elsevier Ltd. All rights reserved.

About cosmic gamma ray lines

NASA Astrophysics Data System (ADS)

Diehl, Roland

2017-06-01

Gamma ray lines from cosmic sources convey the action of nuclear reactions in cosmic sites and their impacts on astrophysical objects. Gamma rays at characteristic energies result from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. The gamma-ray line from the annihilation of positrons at 511 keV falls into the same energy window, although of different origin. We present here the concepts of cosmic gamma ray spectrometry and the corresponding instruments and missions, followed by a discussion of recent results and the challenges and open issues for the future. Among the lessons learned are the diffuse radioactive afterglow of massive-star nucleosynthesis in 26Al and 60Fe gamma rays, which is now being exploited towards the cycle of matter driven by massive stars and their supernovae; large interstellar cavities and superbubbles have been recognised to be of key importance here. Also, constraints on the complex processes making stars explode as either thermonuclear or core-collapse supernovae are being illuminated by gamma-ray lines, in this case from shortlived radioactivities from 56Ni and 44Ti decays. In particular, the three-dimensionality and asphericities that have recently been recognised as important are enlightened in different ways through such gamma-ray line spectroscopy. Finally, the distribution of positron annihilation gamma ray emission with its puzzling bulge-dominated intensity disctribution is measured through spatially-resolved spectra, which indicate that annihilation conditions may differ in different parts of our Galaxy. But it is now understood that a variety of sources may feed positrons into the interstellar medium, and their characteristics largely get lost during slowing down and propagation of positrons before annihilation; a recent microquasar flare was caught as an opportunity to see positrons annihilate at a source.

EMERALD REVISION 1; PWR accident activity release. [IBM360,370; FORTRAN IV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, T.B.; Tobias, M.L.; Fox, J.N.

The EMERALD program is designed for the calculation of radiation releases and exposures resulting from abnormal operation of a large pressurized water reactor (PWR). The approach used in EMERALD is similar to an analog simulation of a real system. Each component or volume in the plant which contains a radioactive material is represented by a subroutine which keeps track of the production, transfer, decay and absorption of radioactivity in that volume. During the course of the analysis of an accident, activity is transferred from subroutine to subroutine in the program as it would be transferred from place to place inmore » the plant. For example, in the calculation of the doses resulting from a loss-of-coolant accident the program first calculates the activity built up in the fuel before the accident, then releases some of this activity to the containment volume. Some of this activity is then released to the atmosphere. The rates of transfer, leakage, production, cleanup, decay, and release are read in as input to the program. Subroutines are also included which calculate the on-site and off-site radiation exposures at various distances for individual isotopes and sums of isotopes. The program contains a library of physical data for the twenty-five isotopes of most interest in licensing calculations, and other isotopes can be added or substituted. Because of the flexible nature of the simulation approach, the EMERALD program can be used for most calculations involving the production and release of radioactive materials during abnormal operation of a PWR. These include design, operational, and licensing studies.IBM360,370; FORTRAN IV; OS/360,370 (IBM360,370); 520K bytes of memory are required..« less

Reexamining cluster radioactivity in trans-lead nuclei with consideration of specific density distributions in daughter nuclei and clusters

NASA Astrophysics Data System (ADS)

Qian, Yibin; Ren, Zhongzhou; Ni, Dongdong

2016-08-01

We further investigate the cluster emission from heavy nuclei beyond the lead region in the framework of the preformed cluster model. The refined cluster-core potential is constructed by the double-folding integral of the density distributions of the daughter nucleus and the emitted cluster, where the radius or the diffuseness parameter in the Fermi density distribution formula is determined according to the available experimental data on the charge radii and the neutron skin thickness. The Schrödinger equation of the cluster-daughter relative motion is then solved within the outgoing Coulomb wave-function boundary conditions to obtain the decay width. It is found that the present decay width of cluster emitters is clearly enhanced as compared to that in the previous case, which involved the fixed parametrization for the density distributions of daughter nuclei and clusters. Among the whole procedure, the nuclear deformation of clusters is also introduced into the calculations, and the degree of its influence on the final decay half-life is checked to some extent. Moreover, the effect from the bubble density distribution of clusters on the final decay width is carefully discussed by using the central depressed distribution.

Precise measurement of energy of the first excited state of 115Sn (Eexc ≃ 497.3 keV)

NASA Astrophysics Data System (ADS)

Zheltonozhsky, V. A.; Savrasov, A. M.; Strilchuk, N. V.; Tretyak, V. I.

2018-01-01

Single beta decay of 115In to the first excited level of 115Sn (E\\text{exc}≃ 497.3 \\text{keV} ) is known as β-decay with the lowest Qβ value. To determine the Qβ precisely, one has to measure very accurately the E\\text{exc} value. A sample of tin enriched in 115Sn to 50.7% was irradiated by a proton beam at the U-120 accelerator of INR, Kyiv. The 115Sb radioactive isotope, created in the 115Sn(p,n)115Sb reaction, decays with T1/2 = 32 \\text{min} to 115Sn populating the 497 keV level with ≃ 96{%} probability. The total statistics of ˜105 counts collected in the 497 keV peak in a series of measurements, the exact description of the peak shape and the precisely known calibration points around the 497 keV peak allowed to obtain the value E\\text{exc}= 497.342(3) \\text{keV} , which is the most precise to-date. This leads to the following Qβ\\ast value for the decay 115In → 115Sn*: Qβ\\ast= 147 +/- 10 \\text{eV} .

Results from a search for the 0νββ-decay of Te130

NASA Astrophysics Data System (ADS)

Arnaboldi, C.; Artusa, D. R.; Avignone, F. T., III; Balata, M.; Bandac, I.; Barucci, M.; Beeman, J. W.; Bellini, F.; Brofferio, C.; Bucci, C.; Capelli, S.; Carbone, L.; Cebrian, S.; Clemenza, M.; Cremonesi, O.; Creswick, R. J.; de Waard, A.; di Domizio, S.; Dolinski, M. J.; Farach, H. A.; Fiorini, E.; Frossati, G.; Giachero, A.; Giuliani, A.; Gorla, P.; Guardincerri, E.; Gutierrez, T. D.; Haller, E. E.; Maruyama, R. H.; McDonald, R. J.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; Olivieri, E.; Pallavicini, M.; Palmieri, E.; Pasca, E.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Previtali, E.; Risegari, L.; Rosenfeld, C.; Sangiorgio, S.; Sisti, M.; Smith, A. R.; Torres, L.; Ventura, G.; Vignati, M.

2008-09-01

A detailed description of the CUORICINO Te130 neutrinoless double-beta (0νββ) decay experiment is given and recent results are reported. CUORICINO is an array of 62 tellurium oxide (TeO2) bolometers with an active mass of 40.7 kg. It is cooled to ~8-10 mK by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons. It is running in the Laboratori Nazionali del Gran Sasso (LNGS) in Assergi, Italy. These data represent an exposure of 11.83 kg yr or 91 mole-years of Te130. No evidence for 0νββ-decay was observed and a limit of T1/20ν(130Te)⩾3.0×1024y (90% CL) is set. This corresponds to an upper limit on the effective mass, , between 0.19 and 0.68 eV when analyzed with the many published nuclear structure calculations. In the context of these nuclear models, the values fall within the range corresponding to the claim of evidence of 0νββ-decay by H. V. Klapdor-Kleingrothaus The experiment continues to acquire data.

Pharmacokinetics, distribution, metabolism, and excretion of the dual reuptake inhibitor [(14)C]-nefopam in rats.

PubMed

Yu, Jian; Solon, Eric; Shen, Helen; Modi, Nishit B; Mittur, Aravind

2016-11-01

1. This study examined the pharmacokinetics, distribution, metabolism, and excretion of [(14)C] nefopam in rats after a single oral administration. Blood, plasma, and excreta were analyzed for total radioactivity, nefopam, and metabolites. Metabolites were profiled and identified. Radioactivity distribution was determined by quantitative whole-body autoradiography. 2. The pharmacokinetic profiles of total radioactivity and nefopam were similar in male and female rats. Radioactivity partitioned approximately equally between plasma and red blood cells. A majority of the radioactivity was excreted in urine within 24 hours and mass balance was achieved within 7 days. 3. Intact nefopam was a minor component in plasma and excreta. Numerous metabolites were identified in plasma and urine generated by multiple pathways including: hydroxylation/oxidation metabolites (M11, M22a and M22b, M16, M20), some of which were further glucuronidated (M6a to M6c, M7a to M7c, M8a and M8b, M3a to M3d); N-demethylation of nefopam to metabolite M21, which additionally undergoes single or multiple hydroxylations or sulfation (M9, M14, M23), with some of the hydroxylated metabolites further glucuronidated (M2a to M2d). 4. Total radioactivity rapidly distributed with highest concentrations found in the urinary bladder, stomach, liver, kidney medulla, small intestine, uveal tract, and kidney cortex without significant accumulation or persistence. Radioactivity reversibly associated with melanin-containing tissues.

Preliminary Therapy Evaluation of 225Ac-DOTA-c(RGDyK) Demonstrates that Cerenkov Radiation Derived from 225Ac Daughter Decay Can Be Detected by Optical Imaging for In Vivo Tumor Visualization

PubMed Central

Pandya, Darpan N.; Hantgan, Roy; Budzevich, Mikalai M.; Kock, Nancy D.; Morse, David L.; Batista, Izadora; Mintz, Akiva; Li, King C.; Wadas, Thaddeus J.

2016-01-01

The theranostic potential of 225Ac-based radiopharmaceuticals continues to increase as researchers seek innovative ways to harness the nuclear decay of this radioisotope for therapeutic and imaging applications. This communication describes the evaluation of 225Ac-DOTA-c(RGDyK) in both biodistribution and Cerenkov luminescence imaging (CLI) studies. Initially, La-DOTA-c(RGDyK) was prepared as a non-radioactive surrogate to evaluate methodologies that would contribute to an optimized radiochemical synthetic strategy and estimate the radioactive conjugate's affinity for αvβ3, using surface plasmon resonance spectroscopy. Surface plasmon resonance spectroscopy studies revealed the IC50 and Ki of La-DOTA-c(RGDyK) to be 33 ± 13 nM and 26 ± 11 nM, respectively, and suggest that the complexation of the La3+ ion to the conjugate did not significantly alter integrin binding. Furthermore, use of this surrogate allowed optimization of radiochemical synthesis strategies to prepare 225Ac-DOTA-c(RGDyK) with high radiochemical purity and specific activity similar to other 225Ac-based radiopharmaceuticals. This radiopharmaceutical was highly stable in vitro. In vivo biodistribution studies confirmed the radiotracer's ability to target αvβ3 integrin with specificity; specificity was detected in tumor-bearing animals using Cerenkov luminescence imaging. Furthermore, tumor growth control was achieved using non-toxic doses of the radiopharmaceutical in U87mg tumor-bearing nude mice. To our knowledge, this is the first report to describe the CLI of αvβ3+ tumors in live animals using the daughter products derived from 225Ac decay in situ. This concept holds promise to further enhance development of targeted alpha particle therapy. PMID:27022417

Preliminary Therapy Evaluation of (225)Ac-DOTA-c(RGDyK) Demonstrates that Cerenkov Radiation Derived from (225)Ac Daughter Decay Can Be Detected by Optical Imaging for In Vivo Tumor Visualization.

PubMed

Pandya, Darpan N; Hantgan, Roy; Budzevich, Mikalai M; Kock, Nancy D; Morse, David L; Batista, Izadora; Mintz, Akiva; Li, King C; Wadas, Thaddeus J

2016-01-01

The theranostic potential of (225)Ac-based radiopharmaceuticals continues to increase as researchers seek innovative ways to harness the nuclear decay of this radioisotope for therapeutic and imaging applications. This communication describes the evaluation of (225)Ac-DOTA-c(RGDyK) in both biodistribution and Cerenkov luminescence imaging (CLI) studies. Initially, La-DOTA-c(RGDyK) was prepared as a non-radioactive surrogate to evaluate methodologies that would contribute to an optimized radiochemical synthetic strategy and estimate the radioactive conjugate's affinity for αvβ3, using surface plasmon resonance spectroscopy. Surface plasmon resonance spectroscopy studies revealed the IC50 and Ki of La-DOTA-c(RGDyK) to be 33 ± 13 nM and 26 ± 11 nM, respectively, and suggest that the complexation of the La(3+) ion to the conjugate did not significantly alter integrin binding. Furthermore, use of this surrogate allowed optimization of radiochemical synthesis strategies to prepare (225)Ac-DOTA-c(RGDyK) with high radiochemical purity and specific activity similar to other (225)Ac-based radiopharmaceuticals. This radiopharmaceutical was highly stable in vitro. In vivo biodistribution studies confirmed the radiotracer's ability to target αvβ3 integrin with specificity; specificity was detected in tumor-bearing animals using Cerenkov luminescence imaging. Furthermore, tumor growth control was achieved using non-toxic doses of the radiopharmaceutical in U87mg tumor-bearing nude mice. To our knowledge, this is the first report to describe the CLI of αvβ3 (+) tumors in live animals using the daughter products derived from (225)Ac decay in situ. This concept holds promise to further enhance development of targeted alpha particle therapy.

Correlation of radon and thoron concentrations with natural radioactivity of soil in Zonguldak, Turkey

NASA Astrophysics Data System (ADS)

Koray, Abdullah; Akkaya, Gizem; Kahraman, Ayşegül

2017-02-01

Radon and thoron gases are produced by the decay of the radioactive elements those are radium and thorium in the soil. In this study, the correlations between soil radon and thoron concentration with their parent nuclide (226Ra and 232Th) concentrations in collected soil samples from the same locations were evaluated. The result of the measurement shows that the distribution of radon and thoron in soil showed the same tendency as 226Ra and 232Th distribution. It was found a weak correlation between the radon and the 226Ra concentration (R =0.57), and between the thoron and the 232Th concentration (R=0.64). No strong correlation was observed between soil-gas radon and thoron concentration (R = 0.29).

Kinetics of diffusion-controlled annihilation with sparse initial conditions

DOE PAGES

Ben-Naim, Eli; Krapivsky, Paul

2016-12-16

Here, we study diffusion-controlled single-species annihilation with sparse initial conditions. In this random process, particles undergo Brownian motion, and when two particles meet, both disappear. We also focus on sparse initial conditions where particles occupy a subspace of dimension δ that is embedded in a larger space of dimension d. Furthermore, we find that the co-dimension Δ = d - δ governs the behavior. All particles disappear when the co-dimension is sufficiently small, Δ ≤ 2; otherwise, a finite fraction of particles indefinitely survive. We establish the asymptotic behavior of the probability S(t) that a test particle survives until time t. When the subspace is a line, δ = 1, we find inverse logarithmic decay,more » $$S\\sim {(\\mathrm{ln}t)}^{-1}$$, in three dimensions, and a modified power-law decay, $$S\\sim (\\mathrm{ln}t){t}^{-1/2}$$, in two dimensions. In general, the survival probability decays algebraically when Δ < 2, and there is an inverse logarithmic decay at the critical co-dimension Δ = 2.« less

[beta][sup +] decay and cosmic-ray half-life of [sup 91]Nb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hindi, M.M.; Sur, B.; Wedding, K.L.

1993-06-01

In the laboratory, [sup 91]Nb decays by electron capture with a 680-yr half-life. However, as a high energy cosmic ray, it would be stripped of its atomic electrons and would be able to undergo only [beta][sup +] decay. We produced and chemically purified a sample of [sup 91]Nb and observed its decay with an array of Ge and NaI detectors. By following the [beta][sup +] annihilation radiation, we were able to determine the [beta][sup +] branching ratios of both the 105-keV, 61-d isomer and the ground state of [sup 91]Nb. The ground-state branch is (7.7[plus minus]0.8)[times]10[sup [minus]3]% leading to amore » [beta][sup +] partial half-like of (8.8[plus minus]1.9)[times]10[sup 6] yr. Such a value of the half-life makes [sup 91]Nb a good candidate for determining the confinement time of this secondary component of the cosmic rays.« less

DNA-Enabled Integrated Molecular Systems for Computation and Sensing

DTIC Science & Technology

2014-05-21

nanostructures to create nanophotonic networks that undergo nonradiative , near-field energy transfer. This process is known as resonance energy transfer (RET...promoting A to A*. The A* species can then decay nonradiatively or emit a photon of energy hν2.When chromophores are too far away, they cannot efficiently

Analytical solution for multi-species contaminant transport in finite media with time-varying boundary conditions

USDA-ARS?s Scientific Manuscript database

Most analytical solutions available for the equations governing the advective-dispersive transport of multiple solutes undergoing sequential first-order decay reactions have been developed for infinite or semi-infinite spatial domains and steady-state boundary conditions. In this work we present an ...

Nuclear Data Sheets for A = 161

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reich C. W.; Reich C.W.

2011-10-01

The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A = 161 mass chain have been reviewed. Nuclides ranging from Sm (Z = 62) through Os (Z = 76) are included, with Os being a new entry based on a recently reported study. These data are summarized and presented, together with adopted level schemes and properties. This work supersedes the previous evaluation (2000Re14) of the data on these nuclides.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, HyangKyu

The AMoRE (Advanced Mo based Rare process Experiment) collaboration is going to use calcium molybdate crystals to search for neutrinoless double beta decay of {sup 100}Mo isotope. In order to make the crystal, we use calcium carbonate and molybdenum oxide powders as raw materials. Therefore it is highly necessary to reduce potential sources for radioactive backgrounds such as U and Th in the powders. In this talk, we will present our studies for purification of calcium carbonate and molybdenum oxide powders.

Detection Technology in the 21st Century: The Case of Nuclear Weapons of Mass Destruction

DTIC Science & Technology

2008-03-26

Weapons of Mass Destruction FORMAT : Strategy Research Project DATE: 26 March 2008 WORD COUNT: 6,764 PAGES: 25 KEY TERMS: National Security, Deterrence...stocks remaining in Ukraine, Belarus, Uzbekistan, and other former Soviet and Eastern European states, and the unknown amounts of highly enriched uranium ...detect emissions from the decay of radioactive nuclides, which can occur naturally, such as uranium and thorium, or are manmade, such as plutonium

Coulomb Excitation of Neutron-Rich Cd Isotopes at REX-ISOLDE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroell, Th.; Behrens, T.; Kruecken, R.

2005-11-21

We report on the 'safe' Coulomb excitation of neutron-rich Cd isotopes in the vicinity of the doubly magic nucleus 132Sn. The radioactive nuclei have been produced by ISOLDE at CERN and postaccelerated by the REX-ISOLDE facility. The {gamma}-decay of excited states has been detected by the MINIBALL array. Preliminary results for the B(E2) values of 122,124Cd are consistent with expectations from phenomenological systematics.

Coulomb excitation of neutron-rich Cd isotopes at REX-ISOLDE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroell, Th.; Behrens, T.; Kruecken, R.

2006-04-26

We report on the 'safe' Coulomb excitation of neutron-rich Cd isotopes in the vicinity of the doubly magic nucleus 132Sn. The radioactive nuclei have been produced by ISOLDE at CERN and postaccelerated by the REX-ISOLDE facility. The {gamma}-decay of excited states has been detected by the MINIBALL array. Preliminary results for the B(E2) values of 122,124Cd are consistent with expectations from phenomenological systematics.

High-Precision Half-Life Measurement for the Superallowed β+ Emitter Alm26

NASA Astrophysics Data System (ADS)

Finlay, P.; Ettenauer, S.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Cross, D. S.; Demand, G.; Djongolov, M.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hackman, G.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Sumithrarachchi, C. S.; Triambak, S.; Williams, S. J.

2011-01-01

A high-precision half-life measurement for the superallowed β+ emitter Alm26 was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T1/2=6346.54±0.46stat±0.60systms, consistent with, but 2.5 times more precise than, the previous world average. The Alm26 half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed β decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected Ft value for Alm26, 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi β-decay studies used to test the conserved vector current hypothesis and determine the Vud element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.

Concept design of a time-of-flight spectrometer for the measurement of the energy of alpha particles.

PubMed

García-Toraño, E

2018-04-01

The knowledge of the energies of the alpha particles emitted in the radioactive decay of a nuclide is a key factor in the construction of its decay scheme. Virtually all existing data are based on a few absolute measurements made by magnetic spectrometry (MS), to which most other MS measurements are traced. An alternative solution would be the use of time-of-flight detectors. This paper discusses the main aspects to be considered in the design of such detectors, and the performances that could be reasonably expected. Based on the concepts discussed here, it is estimated that an energy resolution about 2.5keV may be attainable with a good quality source. Copyright © 2017 Elsevier Ltd. All rights reserved.

STEFFY-software to calculate nuclide-specific total counting efficiency in well-type γ-ray detectors.

PubMed

Pommé, S

2012-09-01

A software package is presented to calculate the total counting efficiency for the decay of radionuclides in a well-type γ-ray detector. It is specifically applied to primary standardisation of activity by means of 4πγ-counting with a NaI(Tl) well-type scintillation detector. As an alternative to Monte Carlo simulations, the software combines good accuracy with superior speed and ease-of-use. It is also well suited to investigate uncertainties associated with the 4πγ-counting method for a variety of radionuclides and detector dimensions. In this paper, the underlying analytical models for the radioactive decay and subsequent counting efficiency of the emitted radiation in the detector are summarised. Copyright © 2012 Elsevier Ltd. All rights reserved.

Precision Tests of the Electroweak Interaction using Trapped Atoms and Ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melconian, Daniel George

The objective of the proposed research is to study fundamental aspects of the electroweak interaction via precision measurements in beta decay to test our current understanding of fundamental particles and forces as contained in the so-called "Standard Model" of particle physics. By comparing elegant experiments to rigorous theoretical predictions, we will either confirm the Standard Model to a higher degree and rule out models which seek to extend it, or find evidence of new physics and help guide theorists in developing the New Standard Model. The use of ion and neutral atom traps at radioactive ion beam facilities has openedmore » up a new vista in precision low-energy nuclear physics experiments. Traps provide an ideal source of decaying atoms: they can be extremely cold (~1 mK); they are compact (~1 mm^3); and perhaps most importantly, the daughter particles escape with negligible distortions to their momenta in a scattering-free, open environment. The project is taking advantage of these technologies and applying them to precision beta-decay studies at radioactive beam facilities. The program consists of two complementary efforts: 1) Ion traps are an extremely versatile tool for purifying, cooling and bunching low-energy beams of short-lived nuclei. A large-bore (210~mm) superconducting 7-Tesla solenoid is at the heart of a Penning trap system for which there is a dedicated beamline at T-REX, the upgraded radioactive beam facility at the Cyclotron Institute, Texas A&M University. In addition to providing a general-purpose decay station, the flagship program for this system is measuring the ft-values and beta-neutrino correlation parameters from isospin T=2 superallowed beta-delayed proton decays, complimenting and expanding the already strong program in fundamental interactions at the Institute. 2) A magneto-optical trap is being used at the TRIUMF Neutral Atom Trap facility to observe the (un)polarized angular distribution parameters of isotopes of potassium. We are able to highly polarize laser-cooled atoms and observe their decay with unprecedented precision. The correlation of the daughter beta particle with the initial nuclear spin as well as other correlations are sensitive to physics beyond the Standard Model. Both of these cutting-edge and exciting research efforts will test our understanding of the fundamental symmetries underlying our current theory of electroweak interactions. Complementary to high-energy collider experiments, these low-energy nuclear physics "table-top" experiments will search for new particles and interactions which are not already described by the Standard Model of particle physics. The value of this research is recognized to be cross-disciplinary, exciting and potentially revolutionary in our understanding of nature's fundamental interactions. Accordingly, it has been endorsed by the recent (2007) Nuclear Science Advisory Committee's Long Range Plan as part of their recommendation for a "New Standard Model Initiative." In addition to the near-term benefits of scholarly publications and visibility through description of this work at international conferences, an important benefit of this research program is the training of new, young and enthusiastic nuclear physicists. Participants in this demanding and rewarding field develop a very strong background in physics with experience in a range of its subfields since we use atomic techniques and apply them to a nuclear physics experiment which in the end tests the theories of high-energy physics.« less

Surface horizontal logging for uranium and its decay products at a Superfund site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gadeken, L.L.; Madigan, W.P.

1995-12-31

The United States Department of Energy (DOE) is now responsible for the environmental restoration and management of a number of sites where nuclear activities occurred during the Cold War. The DOE sponsored an Expedited Site Characterization performed by Ames Laboratory at the St. Louis (Missouri) Airport Site (SLAPS) during August--September, 1994. Uranium processing occurred at SLAPS during the Cold War and there is now significant residual radioactive contamination. Surveys associated the highest radioactivity levels at SLAPS with the ``barium cake`` (AJ-4) waste areas. This paper reports on continuous gamma ray spectroscopy measurements to identify the emitting, isotopes and to quantifymore » the amount of radioactivity present for each. An oilfield wireline gamma ray spectrometry sonde (the Compensated Spectral Natural Gamma instrument) was adapted to perform horizontal measurements with the detector section 3 ft above the soil surface. The CSNG detector is a 2-in.-diameter by 12-in.-long sodium iodide crystal. The spectrometry data are processed by a weighted-least-squares algorithm that incorporates whole spectrum responses for the radioisotopes of interest. The radioactivities are reported in pCi/g units for each isotope, and a depth-of-emission estimate is found by Compton-downscattering spectral shape analysis.« less

The secondary supernova machine: Gravitational compression, stored Coulomb energy, and SNII displays

NASA Astrophysics Data System (ADS)

Clayton, Donald D.; Meyer, Bradley S.

2016-04-01

Radioactive power for several delayed optical displays of core-collapse supernovae is commonly described as having been provided by decays of 56Ni nuclei. This review analyses the provenance of that energy more deeply: the form in which that energy is stored; what mechanical work causes its storage; what conservation laws demand that it be stored; and why its release is fortuitously delayed for about 106 s into a greatly expanded supernova envelope. We call the unifying picture of those energy transfers the secondary supernova machine owing to its machine-like properties; namely, mechanical work forces storage of large increases of nuclear Coulomb energy, a positive energy component within new nuclei synthesized by the secondary machine. That positive-energy increase occurs despite the fusion decreasing negative total energy within nuclei. The excess of the Coulomb energy can later be radiated, accounting for the intense radioactivity in supernovae. Detailed familiarity with this machine is the focus of this review. The stored positive-energy component created by the machine will not be reduced until roughly 106 s later by radioactive emissions (EC and β +) owing to the slowness of weak decays. The delayed energy provided by the secondary supernova machine is a few × 1049 erg, much smaller than the one percent of the 1053 erg collapse that causes the prompt ejection of matter; however, that relatively small stored energy is vital for activation of the late displays. The conceptual basis of the secondary supernova machine provides a new framework for understanding the energy source for late SNII displays. We demonstrate the nuclear dynamics with nuclear network abundance calculations, with a model of sudden compression and reexpansion of the nuclear gas, and with nuclear energy decompositions of a nuclear-mass law. These tools identify excess Coulomb energy, a positive-energy component of the total negative nuclear energy, as the late activation energy. If the value of fundamental charge e were smaller, SNII would not be so profoundly radioactive. Excess Coulomb energy has been carried within nuclei radially for roughly 109 km before being radiated into greatly expanded supernova remnants. The Coulomb force claims heretofore unacknowledged significance for supernova physics.

Radiolytic hydrogen production in basaltic basement of the South Pacific Gyre

NASA Astrophysics Data System (ADS)

Dzaugis, M. E.; Spivack, A. J.; Dunlea, A. G.; Murray, R. W.; Kelley, K. A.; D'Hondt, S. L.

2013-12-01

Water radiolysis is the decomposition of water molecules due to interactions with ionizing radiation from the natural decay of radioactive elements, such as uranium (238U, 235U), thorium (232Th) and potassium (40K). This abiotic process produces electron donors (e.g., H2) and acceptors (e.g., O2) that microorganisms can metabolize for energy. Although water radiolysis has been examined in deep continental crust (Lin et al., 2005) and marine sediment (Blair et al., 2007), it has not been rigorously addressed in oceanic basement. The submarine depth to which life extends on Earth, and the potential for life in basaltic aquifers of other worlds (such as Mars and Europa), may depend on radiolytic production of electron donors and acceptors. In order to quantify the extent to which water radiolysis occurs in the subseafloor basaltic basement, we (i) quantified radioactive element concentrations of basement samples from Integrated Ocean Drilling Program (IODP) Expedition 329 and (ii) developed a quantitative model of H2 production by water radiolysis in the basement aquifer. Modeling radiolytic production of H2 in oceanic basement is difficult because the basement is a heterogeneous environment. Microscale changes in physical properties and chemical composition cause microscale variation in water radiolysis within the basement. During radioactive decay, alpha particles, beta particles and gamma rays are emitted, each with a spectrum of characteristic energies. The distance over which radiation is attenuated depends on the kind of radiation (alpha, beta or gamma), initial energy, and the absorbing material. These properties and the concentration of radioactive elements provide the basis for our preliminary model. We are using inductively coupled plasma emission spectroscopy (ICP-ES), mass spectrometry (ICP-MS) and laser ablation (LA ICP-MS) to map variation in radioelement concentrations from phase to phase (e.g., across successive alteration halos to unaltered rock). The last step in our model combines (i) the rate at which radiation energy is transferred to the water with (ii) published H2 yields per rate of energy transfer.

Natural radioactivity and trace metals in crude oils: implication for health.

PubMed

Ajayi, T R; Torto, N; Tchokossa, P; Akinlua, A

2009-02-01

Crude oil samples were collected from six different fields in the central Niger Delta in order to determine their natural radioactivity and trace element contents, with the aim of assessing the radiological health implications and environmental health hazard of the metals, and also to provide natural radioactivity baseline data that could be used for more comprehensive future study in this respect. The activity concentrations of the radionuclides were measured using a well, accurately calibrated and shielded vertical cryostat, Canberra coaxial high-purity germanium (HPGe) detector system, and the derived doses were evaluated. The metal concentrations were determined by the graphite furnace atomic absorption spectroscopic (GFAAS) method. The radionuclides identified with reliable regularity belong to the decay series of naturally occurring radionuclides headed by (238)U and (232)Th along with the non-decay series radionuclide, (40)K. The averaged activity concentrations obtained were 10.52 +/- 0.03 Bq kg(-1), 0.80 +/- 0.37 Bq kg(-1) and 0.17 +/- 0.09 Bq kg(-1) for (40)K, (238)U and (232)Th, respectively. The equivalent doses were very low, ranging from 0.0028 to 0.012 mSv year(-1) with a mean value of 0.0070 mSv year(-1). The results obtained were low, and hence, the radioactivity content from the crude oils in the Niger delta oil province of Nigeria do not constitute any health hazard to occupationally exposed workers, the public and the end user. The concentrations of the elements (As, Cd, Co, Fe, Mn, Ni, Se and V) determined ranged from 0.73 to 202.90 ppb with an average of 74.35 ppb for the oil samples analysed. The pattern of occurrence of each element agreed with the earlier studies from other parts of the Niger Delta. It was obvious from this study and previous ones that the Niger Delta oils have low metal contents. However, despite the low concentrations, they could still pose an intrinsic health hazard considering their cumulative effects in the environment. Also, various studies on the impact of oil spillage and activities of oil exploration and production on organisms in the immediate environment suggest this.

A kinematic model to estimate effective dose of radioactive substances in a human body

NASA Astrophysics Data System (ADS)

Sasaki, S.; Yamada, T.

2013-05-01

The great earthquake occurred in the north-east area in Japan in March 11, 2011. Facility system to control Fukushima Daiichi nuclear power station was completely destroyed by the following giant tsunami. From the damaged reactor containment vessels, an amount of radioactive substances had leaked and diffused in the vicinity of this station. Radiological internal exposure became a serious social issue both in Japan and all over the world. The present study provides an easily understandable, kinematic-based model to estimate the effective dose of radioactive substances in a human body by simplifying the complicated mechanism of metabolism. International Commission on Radiological Protection (ICRP) has developed a sophisticated model, which is well-known as a standard method to calculate the effective dose for radiological protection. However, owing to that ICRP method is fine, it is rather difficult for non-professional people of radiology to gasp the whole images of the movement and the influences of radioactive substances in a human body. Therefore, in the present paper we propose a newly-derived and easily-understandable model to estimate the effective dose. The present method is very similar with the traditional and conventional tank model in hydrology. Ingestion flux of radioactive substances corresponds to rain intensity and the storage of radioactive substances to the water storage in a basin in runoff analysis. The key of the present method is to estimate the energy radiated in the radioactive nuclear disintegration of an atom by using classical theory of β decay and special relativity for various kinds of radioactive atoms. The parameters used in this model are only physical half-time and biological half-time, and there are no operational parameters or coefficients to adjust our theoretical runoff to ICRP. Figure shows the time-varying effective dose with ingestion duration, and we can confirm the validity of our model. The time-varying effective dose with ingestion duration

SU-D-9A-01: Listmode-Driven Optimal Gating (OG) Respiratory Motion Management: Potential Impact On Quantitative PET Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, K; Hristov, D

2014-06-01

Purpose: To evaluate the potential impact of listmode-driven amplitude based optimal gating (OG) respiratory motion management technique on quantitative PET imaging. Methods: During the PET acquisitions, an optical camera tracked and recorded the motion of a tool placed on top of patients' torso. PET event data were utilized to detect and derive a motion signal that is directly coupled with a specific internal organ. A radioactivity-trace was generated from listmode data by accumulating all prompt counts in temporal bins matching the sampling rate of the external tracking device. Decay correction for 18F was performed. The image reconstructions using OG respiratorymore » motion management technique that uses 35% of total radioactivity counts within limited motion amplitudes were performed with external motion and radioactivity traces separately with ordered subset expectation maximization (OSEM) with 2 iterations and 21 subsets. Standard uptake values (SUVs) in a tumor region were calculated to measure the effect of using radioactivity trace for motion compensation. Motion-blurred 3D static PET image was also reconstructed with all counts and the SUVs derived from OG images were compared with SUVs from 3D images. Results: A 5.7 % increase of the maximum SUV in the lesion was found for optimal gating image reconstruction with radioactivity trace when compared to a static 3D image. The mean and maximum SUVs on the image that was reconstructed with radioactivity trace were found comparable (0.4 % and 4.5 % increase, respectively) to the values derived from the image that was reconstructed with external trace. Conclusion: The image reconstructed using radioactivity trace showed that the blurring due to the motion was reduced with impact on derived SUVs. The resolution and contrast of the images reconstructed with radioactivity trace were comparable to the resolution and contrast of the images reconstructed with external respiratory traces. Research supported by Siemens.« less

Testing atomic mass models with radioactive beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haustein, P.E.

1989-01-01

Significantly increased yields of new or poorly characterized exotic isotopes that lie far from beta-decay stability can be expected when radioactive beams are used to produce these nuclides. Measurements of the masses of these new species are very important. Such measurements are motivated by the general tendency of mass models to diverge from one another upon excursions from the line of beta-stability. Therefore in these regions (where atomic mass data are presently nonexistent or sparse) the models can be tested rigorously to highlight the features that affect the quality of their short-range and long-range extrapolation properties. Selection of systems tomore » study can be guided, in part, by a desire to probe those mass regions where distinctions among mass models are most apparent and where yields of exotic isotopes, produced via radioactive beams, can be optimized. Identification of models in such regions that have good predictive properties will aid materially in guiding the selection of additional experiments which ultimately will provide expansion of the atomic mass database for further refinement of the mass models. 6 refs., 5 figs.« less

Radioactivity in the galactic plane

NASA Technical Reports Server (NTRS)

Walraven, G. D.; Haymes, R. C.

1976-01-01

The paper reports the detection of a large concentration of interstellar radioactivity during balloon-altitude measurements of gamma-ray energy spectra in the band between 0.02 and 12.27 MeV from galactic and extragalactic sources. Enhanced counting rates were observed in three directions towards the plane of the Galaxy; a power-law energy spectrum is computed for one of these directions (designated B 10). A large statistical deviation from the power law in a 1.0-FWHM interval centered near 1.16 MeV is discussed, and the existence of a nuclear gamma-ray line at 1.15 MeV in B 10 is postulated. It is suggested that Ca-44, which emits gamma radiation at 1.156 MeV following the decay of radioactive Sc-44, is a likely candidate for this line, noting that Sc-44 arises from Ti-44 according to explosive models of supernova nucleosynthesis. The 1.16-MeV line flux inferred from the present data is shown to equal the predicted flux for a supernova at a distance of approximately 3 kpc and an age not exceeding about 100 years.

The uses of radiotracers in the life sciences

NASA Astrophysics Data System (ADS)

Ruth, Thomas J.

2009-01-01

Radionuclides have been used to follow physical, chemical and biological processes almost from the time of their discovery. Probably the application with the biggest impact has been in the medical field where radionuclides have been incorporated into biologically active molecules and used to diagnose a wide variety of diseases and to treat many disorders. Other uses in the life sciences, in general, are related to using a radioactive isotope as marker for an existing species such as nitrogen-13 in plant studies or copper-67 to track copper catalysts in phytoplankton. This review describes in general terms these uses as well as providing the reader with the background related to the physical properties of radioactive decay, the concepts associated with the production of radionuclides using reactors or accelerators and the fundamentals of imaging radioactivity. The advances in imaging technology in recent years has had a profound impact on the use of radionuclides in positron emission tomography and the coupling of other imaging modalities to provide very precise insights into human disease. The variety of uses for radiotracers in science is almost boundless dependent only upon ones imagination.

Isomer beam elastic scattering: 26mAl(p, p) for astrophysics

NASA Astrophysics Data System (ADS)

Kahl, D.; Shimizu, H.; Yamaguchi, H.; Abe, K.; Beliuskina, O.; Cha, S. M.; Chae, K. Y.; Chen, A. A.; Ge, Z.; Hayakawa, S.; Imai, N.; Iwasa, N.; Kim, A.; Kim, D. H.; Kim, M. J.; Kubono, S.; Kwag, M. S.; Liang, J.; Moon, J. Y.; Nishimura, S.; Oka, S.; Park, S. Y.; Psaltis, A.; Teranishi, T.; Ueno, Y.; Yang, L.

2018-01-01

The advent of radioactive ground-state beams some three decades ago ultimately sparked a revolution in our understanding of nuclear physics. However, studies with radioactive isomer beams are sparse and have often required sophisticated apparatuses coupled with the technologies of ground-state beams due to typical mass differences on the order of hundreds of keV and vastly different lifetimes for isomers. We present an application of a isomeric beam of 26mAl to one of the most famous observables in nuclear astrophysics: galactic 26Al. The characteristic decay of 26Al in the Galaxy was the first such specific radioactivity to be observed originating from outside the Earth some four decades ago. We present a newly-developed, novel technique to probe the structure of low-spin states in 27Si. Using the Center for Nuclear Study low-energy radioisotope beam separator (CRIB), we report on the measurement of 26mAl proton resonant elastic scattering conducted with a thick target in inverse kinematics. The preliminary results of this on-going study are presented.

Scavenging of radioactive soluble gases from inhomogeneous atmosphere by evaporating rain droplets.

PubMed

Elperin, Tov; Fominykh, Andrew; Krasovitov, Boris

2015-05-01

We analyze effects of inhomogeneous concentration and temperature distributions in the atmosphere, rain droplet evaporation and radioactive decay of soluble gases on the rate of trace gas scavenging by rain. We employ a one-dimensional model of precipitation scavenging of radioactive soluble gaseous pollutants that is valid for small gradients and non-uniform initial altitudinal distributions of temperature and concentration in the atmosphere. We assume that conditions of equilibrium evaporation of rain droplets are fulfilled. It is demonstrated that transient altitudinal distribution of concentration under the influence of rain is determined by the linear wave equation that describes propagation of a scavenging wave front. The obtained equation is solved by the method of characteristics. Scavenging coefficients are calculated for wet removal of gaseous iodine-131 and tritiated water vapor (HTO) for the exponential initial distribution of trace gases concentration in the atmosphere and linear temperature distribution. Theoretical predictions of the dependence of the magnitude of the scavenging coefficient on rain intensity for tritiated water vapor are in good agreement with the available atmospheric measurements. Copyright © 2015 Elsevier Ltd. All rights reserved.

Background-free search for neutrinoless double-β decay of 76Ge with GERDA.

PubMed

2017-04-05

Many extensions of the Standard Model of particle physics explain the dominance of matter over antimatter in our Universe by neutrinos being their own antiparticles. This would imply the existence of neutrinoless double-β decay, which is an extremely rare lepton-number-violating radioactive decay process whose detection requires the utmost background suppression. Among the programmes that aim to detect this decay, the GERDA Collaboration is searching for neutrinoless double-β decay of 76 Ge by operating bare detectors, made of germanium with an enriched 76 Ge fraction, in liquid argon. After having completed Phase I of data taking, we have recently launched Phase II. Here we report that in GERDA Phase II we have achieved a background level of approximately 10 -3 counts keV -1 kg -1 yr -1 . This implies that the experiment is background-free, even when increasing the exposure up to design level. This is achieved by use of an active veto system, superior germanium detector energy resolution and improved background recognition of our new detectors. No signal of neutrinoless double-β decay was found when Phase I and Phase II data were combined, and we deduce a lower-limit half-life of 5.3 × 10 25 years at the 90 per cent confidence level. Our half-life sensitivity of 4.0 × 10 25 years is competitive with the best experiments that use a substantially larger isotope mass. The potential of an essentially background-free search for neutrinoless double-β decay will facilitate a larger germanium experiment with sensitivity levels that will bring us closer to clarifying whether neutrinos are their own antiparticles.

Background-free search for neutrinoless double-β decay of 76Ge with GERDA

NASA Astrophysics Data System (ADS)

Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Marco, N.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.; GERDA Collaboration

2017-04-01

Many extensions of the Standard Model of particle physics explain the dominance of matter over antimatter in our Universe by neutrinos being their own antiparticles. This would imply the existence of neutrinoless double-β decay, which is an extremely rare lepton-number-violating radioactive decay process whose detection requires the utmost background suppression. Among the programmes that aim to detect this decay, the GERDA Collaboration is searching for neutrinoless double-β decay of 76Ge by operating bare detectors, made of germanium with an enriched 76Ge fraction, in liquid argon. After having completed Phase I of data taking, we have recently launched Phase II. Here we report that in GERDA Phase II we have achieved a background level of approximately 10-3 counts keV-1 kg-1 yr-1. This implies that the experiment is background-free, even when increasing the exposure up to design level. This is achieved by use of an active veto system, superior germanium detector energy resolution and improved background recognition of our new detectors. No signal of neutrinoless double-β decay was found when Phase I and Phase II data were combined, and we deduce a lower-limit half-life of 5.3 × 1025 years at the 90 per cent confidence level. Our half-life sensitivity of 4.0 × 1025 years is competitive with the best experiments that use a substantially larger isotope mass. The potential of an essentially background-free search for neutrinoless double-β decay will facilitate a larger germanium experiment with sensitivity levels that will bring us closer to clarifying whether neutrinos are their own antiparticles.

Dynamical Cluster-decay Model (DCM) applied to 9Li+208Pb reaction

NASA Astrophysics Data System (ADS)

Kaur, Arshdeep; Hemdeep; Kaushal, Pooja; Behera, Bivash R.; Gupta, Raj K.

2017-10-01

The decay mechanism of 217At* formed in 9Li+208Pb reaction is studied within the dynamical cluster-decay model (DCM) at various center-of-mass energies. The aim is to see the behavior of a light neutron-rich radioactive beam on a doubly-magic target nucleus for the (total) fusion cross section σfus and the individual decay channel cross sections. Experimentally, only the isotopic yield of heavy mass residues * 211- 214At [equivalently, the light-particles (LPs) evaporation residue cross sections σxn for x = 3- 6 neutrons emission] are measured, with the fusion-fission (ff) component σff taken zero. For a fixed neck-length parameter ΔR, the only parameter in the DCM, we are able to fit σfus =∑x=16σxn almost exactly for 9Li on 208Pb at all E c . m .'s. However, the observed individual decay channels (3n-6n) are very poorly fitted, with unobserved channels (1n, 2n) and σff strongly over-estimated. Different ΔR values, meaning thereby different reaction time scales, are required to fit individually both the observed and unobserved evaporation residue channels (1n-6n) and σff, but then the compound nucleus (CN) contribution σCN is very small (< 1%), and the non-compound nucleus (nCN) decay cross section σnCN contributes the most towards total σfus (=σCN +σnCN). Thus, the 9Li induced reaction on doubly-magic 208Pb is more of a quasi-fission-like nCN decay, which is further analyzed in terms of the statistical CN formation probability PCN and CN survival probability Psurv. For the reaction under study, PCN < < 1 and Psurv → 1, in particular at above barrier energies.

Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant.

PubMed

Beddow, H; Black, S; Read, D

2006-01-01

In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by 238U and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (< or =8.8 Bq/g) of 238U were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (< or =11 Bq/g) of 226Ra were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution.

The use of γ-rays analysis by HPGe detector to assess the gross alpha and beta activities in waters.

PubMed

Casagrande, M F S; Bonotto, D M

2018-07-01

This paper describes an alternative method for evaluating gross alpha and beta radioactivity in waters by using γ-rays analysis performed with hyper-pure germanium detector (HPGe). Several gamma emissions related to α and β - decays were used to provide the activity concentration data due to natural radionuclides commonly present in waters like 40 K and those belonging to the 238 U and 232 Th decay series. The most suitable gamma emissions related to β - decays were 214 Bi (1120.29 keV, 238 U series) and 208 Tl (583.19 keV, 232 Th series) as the equation in activity concentration yielded values compatible to those generated by the formula taking into account the detection efficiency. The absence of isolated and intense γ-rays peaks associated to α decays limited the choice to 226 Ra (186.21 keV, 238 U series) and 224 Ra (240.99 keV, 232 Th series). In these cases, it was adopted appropriate correction factors involving the absolute intensities and specific activities for avoiding the interferences of other γ-rays energies. The critical level of detection across the 186-1461 keV energy region corresponded to 0.010, 0.023, 0.038, 0.086, and 0.042 Bq/L, respectively, for 226 Ra, 224 Ra, 208 Tl, 214 Bi and 40 K. It is much lower than the WHO guideline reference value for gross alpha (0.5 Bq/L) and beta (1.0 Bq/L) in waters. The method applicability was checked by the analysis of groundwater samples from different aquifer systems occurring in the Brazilian states of São Paulo, Minas Gerais and Mato Grosso do Sul. The waters exhibit very different chemical composition and the samples with the highest radioactivity levels were those associated with lithotypes possessing enhanced uranium and thorium levels. The technique allowed directly discard the 40 K contribution to the gross beta activity as potassium is an essential element for humans. Copyright © 2018 Elsevier Ltd. All rights reserved.

Decay of Plutonium isotopes via spontaneous and heavy-ion induced fission paths

NASA Astrophysics Data System (ADS)

Sharma, Kanishka; Sawhney, Gudveen; Sharma, Manoj K.; Gupta, Raj K.

2018-04-01

Based on the collective clusterization approach, we have extended our earlier study on α-decay, exotic cluster-decay, and heavy particle radioactivity, to the phenomenon of spontaneous fission (SF) in the ground-state (g.s.) decays of even mass 234-246Pu parents. The calculations for the SF half-lives of these Pu-isotopes have been made within the framework of preformed cluster model (PCM), both for spherical as well as β2-deformed choices of shapes, and a comparison is made with the relevant available experimental data, which prefer spherical shapes. The importance of the orientation degree of freedom (hot compact or cold elongated configurations) is also explored. Next, in order to look for the exclusive role of heavy-ion induced fission, the dynamics of 6He + 238U reaction forming 244Pu* is studied over the center of mass energy range of E c . m . = 15.0- 28.8MeV, using the dynamical cluster-decay model (DCM), an extension of the PCM with temperature T- and angular momentum ℓ-effects included. The β2-deformed fragments of 244Pu* in the mass range A2 = 106- 113 (plus their complementary heavy fragments), corresponding to asymmetric fission peaks, are found contributing towards the fission cross-section. Finally, the potential energy surfaces and barrier modification effects are presented for the relative comparison of spontaneous and the heavy-ion induced fission processes. Both are found to behave similar with respect to the probable emission of fragments and hence point out to the shell closure property of the decay fragments.

Simultaneous investigation of the T =1 (Jπ=0+) and T =0 (Jπ=9+) β decays in 70Br

NASA Astrophysics Data System (ADS)

Morales, A. I.; Algora, A.; Rubio, B.; Kaneko, K.; Nishimura, S.; Aguilera, P.; Orrigo, S. E. A.; Molina, F.; de Angelis, G.; Recchia, F.; Kiss, G.; Phong, V. H.; Wu, J.; Nishimura, D.; Oikawa, H.; Goigoux, T.; Giovinazzo, J.; Ascher, P.; Agramunt, J.; Ahn, D. S.; Baba, H.; Blank, B.; Borcea, C.; Boso, A.; Davies, P.; Diel, F.; Dombrádi, Zs.; Doornenbal, P.; Eberth, J.; de France, G.; Fujita, Y.; Fukuda, N.; Ganioglu, E.; Gelletly, W.; Gerbaux, M.; Grévy, S.; Guadilla, V.; Inabe, N.; Isobe, T.; Kojouharov, I.; Korten, W.; Kubo, T.; Kubono, S.; Kurtukián Nieto, T.; Kurz, N.; Lee, J.; Lenzi, S.; Liu, J.; Lokotko, T.; Lubos, D.; Magron, C.; Montaner-Pizá, A.; Napoli, D. R.; Sakurai, H.; Schaffner, H.; Shimizu, Y.; Sidong, C.; Söderström, P.-A.; Sumikama, T.; Suzuki, H.; Takeda, H.; Takei, Y.; Tanaka, M.; Yagi, S.

2017-06-01

The β decay of the odd-odd nucleus 70Br has been investigated with the BigRIPS and EURICA setups at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center. The T =0 (Jπ=9+ ) and T =1 (Jπ=0+ ) isomers have both been produced in in-flight fragmentation of 78Kr with ratios of 41.6(8)% and 58.4(8)%, respectively. A half-life of t1 /2=2157-49+53 ms has been measured for the Jπ=9+ isomer from γ -ray time decay analysis. Based on this result, we provide a new value of the half-life for the Jπ=0+ ground state of 70Br,t1 /2=78.42 ±0.51 ms, which is slightly more precise, and in excellent agreement, with the best measurement reported hitherto in the literature. For this decay, we provide the first estimate of the total branching fraction decaying through the 21+ state in the daughter nucleus 70Se,R (21+)=1.3 ±1.1 % . We also report four new low-intensity γ -ray transitions at 661, 1103, 1561, and 1749 keV following the β decay of the Jπ=9+ isomer. Based on their coincidence relationships, we tentatively propose two new excited states at 3945 and 4752 keV in 70Se with most probable spins and parities of Jπ=(6+) and (8+) , respectively. The observed structure is interpreted with the help of shell-model calculations, which predict a complex interplay between oblate and prolate configurations at low excitation energies.

Paramagnetic colloids: Chaotic routes to clusters and molecules

NASA Astrophysics Data System (ADS)

Abdi, Hamed; Soheilian, Rasam; Erb, Randall M.; Maloney, Craig E.

2018-03-01

We present computer simulations and experiments on dilute suspensions of superparamagnetic particles subject to rotating magnetic fields. We focus on chains of four particles and their decay routes to stable structures. At low rates, the chains track the external field. At intermediate rates, the chains break up but perform a periodic (albeit complex) motion. At sufficiently high rates, the chains generally undergo chaotic motion at short times and decay to either closely packed clusters or more dispersed, colloidal molecules at long times. We show that the transition out of the chaotic states can be described as a Poisson process in both simulation and experiment.

137Cs in soil and fallout around Zagreb (Croatia) at the time of the Fukushima accident.

PubMed

Šoštarić, Marko; Petrinec, Branko; Babić, Dinko

2013-12-01

This paper addresses the noticeable increase of 137Cs activity concentrations in soil and fallout in the area surrounding Zagreb (Croatia) that occurred at the time of the 2011 Fukushima accident. This topic is important for public health as 137Cs is highly toxic due to its long half-life of radioactive decay and chemical similarity to potassium. 137Cs concentrations in fallout were much greater than in soil, but remained present longer in the latter. While being detectable in our measurements, 137Cs did not spread through the food chain in amounts exceeding the maximum allowed level of radioactive food contamination. However, more thorough and consistent measurements need to be done in order to establish the precise activity trends of 137Cs in Zagreb soil and fallout.

Remote micro-encapsulation of curium-gold cermets

NASA Astrophysics Data System (ADS)

Coops, M. S.; Voegele, A. L.; Hayes, W. N.; Sisson, D. H.

1982-09-01

A technique has been developed to produce miniature, high-density capsules of curium-244 oxide contained in three concentric jackets of metallic gold or silver. The final capsules are right circular cylinders, 6.350 mm diameter by (3.18±0.05) mm long, with a minimum density of 11.0 g/cm 3. Each level of containment was soldered or brazed closed, with the outer surface free of detectable alpha contamination. Fabrication was performed in three separate small cells operated by standard master-slave manipulators. Production capsules have been stored for up to five years without indication of dimensional growth or leakage of radioactive contents. The dimensional stability of the capsules is attributed to the microporous structure of the plated-gold structure which permits helium gas resulting from alpha decay to diffuse through the capsule wall while retaining all radioactive materials.

Hyperfine interactions of trans-lead elements studied by nuclear radiations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ansaldo, E.J.

1973-09-16

The applications of nuclear radiation methods to the study of hyperfine interactions (hfi) for elements beyond Pb in the periodic table are reviewed. A general discussion of hfi is presented along with a review of specific methods. The techniques are illustrated whenever possible by their application to the actinides, with emphasis on the unsolved aspects of the results. A special method of sample preparation is ion implantation, in which stable or radioactive ions of practically any element are shot into the host, either by means of isotope separators or the recoil energy of nuclear reactions or radioactive decays. The locationmore » of the implanted (recoiled) atom in the lattice has to be assessed for a reliable determination of the hfi. Therefore, a chapter on the channeling technique is also included. (JRD)« less

Laboratory studies on the removal of radon-born lead from KamLAND's organic liquid scintillator

NASA Astrophysics Data System (ADS)

Keefer, G.; Grant, C.; Piepke, A.; Ebihara, T.; Ikeda, H.; Kishimoto, Y.; Kibe, Y.; Koseki, Y.; Ogawa, M.; Shirai, J.; Takeuchi, S.; Mauger, C.; Zhang, C.; Schweitzer, G.; Berger, B. E.; Dazeley, S.; Decowski, M. P.; Detwiler, J. A.; Djurcic, Z.; Dwyer, D. A.; Efremenko, Y.; Enomoto, S.; Freedman, S. J.; Fujikawa, B. K.; Furuno, K.; Gando, A.; Gando, Y.; Gratta, G.; Hatakeyama, S.; Heeger, K. M.; Hsu, L.; Ichimura, K.; Inoue, K.; Iwamoto, T.; Kamyshkov, Y.; Karwowski, H. J.; Koga, M.; Kozlov, A.; Lane, C. E.; Learned, J. G.; Maricic, J.; Markoff, D. M.; Matsuno, S.; McKee, D.; McKeown, R. D.; Miletic, T.; Mitsui, T.; Motoki, M.; Nakajima, Kyo; Nakajima, Kyohei; Nakamura, K.; O`Donnell, T.; Ogawa, H.; Piquemal, F.; Ricol, J.-S.; Shimizu, I.; Suekane, F.; Suzuki, A.; Svoboda, R.; Tajima, O.; Takemoto, Y.; Tamae, K.; Tolich, K.; Tornow, W.; Watanabe, Hideki; Watanabe, Hiroko; Winslow, L. A.; Yoshida, S.

2015-01-01

The removal of radioactivity from liquid scintillator has been studied in preparation of a low background phase of KamLAND. This paper describes the methods and techniques developed to measure and efficiently extract radon decay products from liquid scintillator. We report the radio-isotope reduction factors obtained when applying various extraction methods. During this study, distillation was identified as the most efficient method for removing radon-born lead from liquid scintillator.

Mass Chain Evaluation for A=95

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basu, S.K.; Sonzogni, A.; Basu, Swapan Kr.

2011-08-01

A full evaluation of the mass chain A = 95 has been done in the ENSDF format taking into account all the available data until June 2009. Excited states populated by in-beam nuclear reactions and by radioactive decay have been considered. The 'evp' editor, developed at the NNDC, has been used for the evaluation. This mass chain was last evaluated in 1993. Many new and improved data were reported since then. A total of 13 nuclei have been evaluated.

Laboratory studies on the removal of radon-born lead from KamLAND׳s organic liquid scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keefer, G.; Grant, C.; Piepke, A.

We studied the removal of radioactivity from liquid scintillator in preparation of a low background phase of KamLAND. We describe the methods and techniques developed to measure and efficiently extract radon decay products from liquid scintillator. Lastly, we report the radio-isotope reduction factors obtained when applying various extraction methods. During this study, distillation was identified as the most efficient method for removing radon daughters from liquid scintillator.

Nuclear Weapons: Comprehensive Test Ban Treaty

DTIC Science & Technology

2006-08-16

Unicorn ,” is to be conducted in a “down-hole” or vertical shaft configuration similar to an underground nuclear test, not in a tunnel, to exercise...operational readiness.42 It is scheduled for FY2006, as noted below. SCEs try to determine if radioactive decay of aged plutonium would degrade weapon...Secretary of Energy Bill Richardson called SCEs “a key part of our scientific program to provide new tools and data that assess age -related complications

Nuclear Weapons: Comprehensive Test Ban Treaty

DTIC Science & Technology

2006-11-15

Unicorn ,” was conducted in a “down-hole” or vertical CRS-18 58 “Nanos Tours Nevada Test Site,” Daily Newsbulletin, Los Alamos National Laboratory...radioactive decay of aged plutonium would degrade weapon performance. Several SCEs have been used to support certification of the W88 pit. (A pit is the...tools and data that assess age -related complications and maintain the reliability and safety of the nation’s nuclear deterrent.”59 As they produce no

Laboratory studies on the removal of radon-born lead from KamLAND׳s organic liquid scintillator

DOE PAGES

Keefer, G.; Grant, C.; Piepke, A.; ...

2014-09-28

We studied the removal of radioactivity from liquid scintillator in preparation of a low background phase of KamLAND. We describe the methods and techniques developed to measure and efficiently extract radon decay products from liquid scintillator. Lastly, we report the radio-isotope reduction factors obtained when applying various extraction methods. During this study, distillation was identified as the most efficient method for removing radon daughters from liquid scintillator.

Energy Capture Module (ECM) for Use in Unmanned Mobile Vehicles (UMVs) With a Specific Study of the Draganflyer X6 UAV

DTIC Science & Technology

2010-09-01

1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE September 2010 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE...Cells • Solar Energy Cells • High Capacity Batteries • Radioisotope Thermoelectric Energy • Energy Capture 7 Hydrogen Fuel Cells Hydrogen fuel is...eventually required recharging Radioisotope Thermoelectric Energy Radioisotope Thermoelectric Generators (RTGs) use isotopic radioactive decay as a

Cr-W-V bainitic/ferritic steel with improved strength and toughness and method of making

DOEpatents

Klueh, Ronald L.; Maziasz, Philip J.

1994-01-01

A high strength, high toughness Cr-W-V ferritic steel composition suitable for fast induced-radioactivity (FIRD) decay after irradiation in a fusion reactor comprises 2.5-3.5 wt % Cr, 2. This invention was made with Government support under contract DE-AC05-840R21400 awarded by the U.S. Department of Energy to Martin Marietta Energy Systems, Inc. and the Government has certain rights in this invention.

Substructure of the inner core of the Earth.

PubMed Central

Herndon, J M

1996-01-01

The rationale is disclosed for a substructure within the Earth's inner core, consisting of an actinide subcore at the center of the Earth, surrounded by a subshell composed of the products of nuclear fission and radioactive decay. Estimates are made as to possible densities, physical dimensions, and chemical compositions. The feasibility for self-sustaining nuclear fission within the subcore is demonstrated, and implications bearing on the structure and geodynamic activity of the inner core are discussed. PMID:11607625

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ullmann, John Leonard; Couture, Aaron Joseph; Koehler, Paul E.

An accurate knowledge of the neutron capture cross section is important for many applications. Experimental measurements are important since theoretical calculations of capture have been notoriously difficult, with the ratio of measured to calculated cross sections often a factor of 2 or more in the 10 keV to 1 MeV region. However, a direct measurement of capture cannot be made on many interesting radioactive nuclides because of their short half-life or backgrounds caused by their nuclear decay. On the other hand, neutron transmission measurements of the total cross section are feasible for a wide range of radioactive nuclides since themore » detectors are far from the sample, and often are less sensitive to decay radiation. The parameters extracted from a total cross section measurement, which include the average resonance spacing, the neutron strength function, and the average total radiation width, (Γ γ), provide tight constraints on the calculation of the capture cross section, and when applied produce much more accurate results. These measurements can be made using the intense epithermal neutron flux at the Lujan Center on relatively small quantities of target material. It was the purpose of this project to investigate and develop the capability to make these measurements. A great deal of progress was made towards establishing this capability during 2016, including setting up the flight path and obtaining preliminary results, but more work remains to be done.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gelles, D. S.; Browning, James Frederick; Snow, Clark Sheldon

Er(D,T){sub 2-x} {sup 3}He{sub x}, erbium di-tritide, films of thicknesses 500 nm, 400 nm, 300 nm, 200 nm, and 100 nm were grown and analyzed by Transmission Electron Microscopy, X-Ray Diffraction, and Ion Beam Analysis to determine variations in film microstructure as a function of film thickness and age, due to the time-dependent build-up of {sup 3}He in the film from the radioactive decay of tritium. Several interesting features were observed: One, the amount of helium released as a function of film thickness is relatively constant. This suggests that the helium is being released only from the near surface regionmore » and that the helium is not diffusing to the surface from the bulk of the film. Two, lenticular helium bubbles are observed as a result of the radioactive decay of tritium into {sup 3}He. These bubbles grow along the [111] crystallographic direction. Three, a helium bubble free zone, or 'denuded zone' is observed near the surface. The size of this region is independent of film thickness. Four, an analysis of secondary diffraction spots in the Transmission Electron Microscopy study indicate that small erbium oxide precipitates, 5-10 nm in size, exist throughout the film. Further, all of the films had large erbium oxide inclusions, in many cases these inclusions span the depth of the film.« less

Introduction to Pits and Weapons Systems (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kautz, D.

2012-07-02

A Nuclear Explosive Package includes the Primary, Secondary, Radiation Case and related components. This is the part of the weapon that produces nuclear yield and it converts mechanical energy into nuclear energy. The pit is composed of materials that allow mechanical energy to be converted to electromagnetic energy. Fabrication processes used are typical of any metal fabrication facility: casting, forming, machining and welding. Some of the materials used in pits include: Plutonium, Uranium, Stainless Steel, Beryllium, Titanium, and Aluminum. Gloveboxes are used for three reasons: (1) Protect workers and public from easily transported, finely divided plutonium oxides - (a) Plutoniummore » is very reactive and produces very fine particulate oxides, (b) While not the 'Most dangerous material in the world' of Manhattan Project lore, plutonium is hazardous to health of workers if not properly controlled; (2) Protect plutonium from reactive materials - (a) Plutonium is extremely reactive at ambient conditions with several components found in air: oxygen, water, hydrogen, (b) As with most reactive metals, reactions with these materials may be violent and difficult to control, (c) As with most fabricated metal products, corrosion may significantly affect the mechanical, chemical, and physical properties of the product; and (3) Provide shielding from radioactive decay products: {alpha}, {gamma}, and {eta} are commonly associated with plutonium decay, as well as highly radioactive materials such as {sup 241}Am and {sup 238}Pu.« less

A multi-layered active target for the study of neutron-unbound nuclides at NSCL

NASA Astrophysics Data System (ADS)

Freeman, Jessica; Gueye, Paul; Redpath, Thomas; MoNA Collaboration

2017-01-01

The characteristics of neutron-unbound nuclides were investigated using a multi-layered Si/Be active target designed for use with the MoNA/LISA setup at the National Superconducting Cyclotron (NSCL). The setup consists of the MoNA/LISA arrays (for neutron detection) and a superconducting sweeper magnet (for charged separation) to identify products following the decay of neutron unbound states. The segmented target consisted of three 700 mg/cm2 beryllium targets and four 0.14 mm thick 62x62 mm2 silicon detectors. As a commissioning experiment for the target the decay of two-neutron unbound 26O populated in a one-proton removal reaction from a radioactive 27F beam was performed. The 27F secondary radioactive beam from the NSCL's Coupled Cyclotron Facility was produced from the fragmentation of a 140 MeV/u 48Ca beam incident on a thick beryllium target and then cleanly selected by the A1900 fragment separator. The energy loss and position spectra of the incoming beam and reaction products were used to calibrate the Silicon detectors to within 1.5% in both energy and position. A dedicated Geant4 model of the target was developed to simulate the energy loss within the target. A description of the experimental setup, simulation work, and energy and position calibration will be presented. DoE/NNSA - DE-NA0000979.

Modeling of Zircon (ZrSiO{sub 4}) and Zirconia (ZrO{sub 2}) using ADF-GUI Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lwin, Maung Tin Moe; Amin, Yusoff Mohd; Kassim, Hasan Abu

2010-07-07

Natural zircon (ZrSiO{sub 4}) has very high concentration of Uranium and Thorium of up to 5000 ppm. Radioactive decay process of alpha particles from these impurities affects some changes like several atomic displacements in the crystalline structure of zircon. The amount of track density caused by alpha particles decay process of these radioactive materials in zircon can be decreased with annealing temperatures from 700 deg. C to 980 deg. C. Recently it has been extensively studied as the possible candidate material for immobilization of fission products and actinides. Besides, zirconia (ZrO{sub 2}), product from natural zircon, is widely used inmore » industrial field because it has excellent chemical and mechanical properties at high temperature. Dielectric constant of monoclinic, cubic and tetragonal ZrO{sub 2} can be found in the range of 22, 35 and 50 by computer simulation works. In recent years, atomistic simulations and modeling have been studied, because a lot of computational techniques can offer atomic-level approaching with minimum errors in estimations. One favorite methods is Density Functional Theory (DFT). In this study, ADF-GUI software from DFT will be used to calculate the frequency and absorption Intensity of zircon and zirconia molecules. The data from calculations will be verified with experimental works such as Raman Spectroscopy, AFM and XRD.« less

The ideal neutrino beams

NASA Astrophysics Data System (ADS)

Lindroos, Mats

2009-06-01

The advance in neutrino oscillation physics is driven by the availability of well characterized and high flux neutrino beams. The three present options for the next generation neutrino oscillation facility are super beams, neutrino factories and beta-beams. A super-beam is a very high intensity classical neutrino beam generated by protons impinging on a target where the neutrinos are generated by the secondary particles decaying in a tunnel down streams of the target. In a neutrino factory the neutrinos are generated from muons decaying in a storage ring with long straight sections pointing towards the detectors. In a beta-beam the neutrinos are also originating from decay in a storage ring but the decaying particles are radioactive ions rather than muons. I will in this presentation review the three options and discuss the pros and cons of each. The present joint design effort for a future high intensity neutrino oscillation in Europe within a common EU supported design study, EURONU, will also be presented. The design study will explore the physics reach, the detectors, the feasibility, the safety issues and the cost for each of the options so that the the community can take a decision on what to build when the facilities presently under exploitation and construction have to be replaced.

20F beta spectrum shape and weak interaction tests

NASA Astrophysics Data System (ADS)

Voytas, Paul; George, Elizabeth; Chuna, Thomas; Naviliat-Cuncic, Oscar; Hughes, Max; Huyan, Xueying; Minamisono, Kei; Paulauskas, Stanley

2016-09-01

Precision measurements of the shape of beta spectra can test our understanding of the weak interaction. We are carrying out a measurement of the shape of the energy spectrum of β particles from 20F decay. The primary motivation is to test the so-called strong form of the conserved vector current (CVC) hypothesis. The measurement should also enable us to place competitive limits on the contributions of exotic tensor couplings in beta decay. We aim to achieve a relative precision better than 3% on the linear contribution to the shape. This represents an order of magnitude improvement compared to previous experiments in 20F. In order to control systematic effects, we are using a technique that takes advantage of high energy radioactive beams at the NSCL to implant the decaying nuclei in scintillation detectors deeply enough that the emitted beta particles cannot escape. The β-particle energy is measured with the implantation detector after switching off the implantation beam. Ancillary detectors are used to identify the 1.633-MeV γ-rays following the 20F β decay for coincidence measurements in order to tag the transition of interest and to reduce backgrounds. We report on the status of the analysis. Supported in part with Awards from the NSCL PAC and the National Science Foundation under Grant No. PHY-1506084.

Diffusion and decay chain of radioisotopes in stagnant water in saturated porous media.

PubMed

Guzmán, Juan; Alvarez-Ramirez, Jose; Escarela-Pérez, Rafael; Vargas, Raúl Alejandro

2014-09-01

The analysis of the diffusion of radioisotopes in stagnant water in saturated porous media is important to validate the performance of barrier systems used in radioactive repositories. In this work a methodology is developed to determine the radioisotope concentration in a two-reservoir configuration: a saturated porous medium with stagnant water is surrounded by two reservoirs. The concentrations are obtained for all the radioisotopes of the decay chain using the concept of overvalued concentration. A methodology, based on the variable separation method, is proposed for the solution of the transport equation. The novelty of the proposed methodology involves the factorization of the overvalued concentration in two factors: one that describes the diffusion without decay and another one that describes the decay without diffusion. It is possible with the proposed methodology to determine the required time to obtain equal injective and diffusive concentrations in reservoirs. In fact, this time is inversely proportional to the diffusion coefficient. In addition, the proposed methodology allows finding the required time to get a linear and constant space distribution of the concentration in porous mediums. This time is inversely proportional to the diffusion coefficient. In order to validate the proposed methodology, the distributions in the radioisotope concentrations are compared with other experimental and numerical works. Copyright © 2014 Elsevier Ltd. All rights reserved.

The structure of nuclei far from stability. [Dept. of Physics and Astronomy, Louisiana State Univ. , Baton Rouge, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zganjar, E.F.

1993-01-01

Studies on nuclei near Z=82 contributed to the establishment of a new region of nuclear deformation and a new class of nuclear structure at closed shells. A important aspect of this work is the establishment of the connection between low-lying 0[sup +] states in even[endash]even nuclei and the occurrence of shape coexistence in the odd-mass neighbors (E0 transitions in [sup 185]Pt, shape coexistence in [sup 184]Pt and [sup 187]Au). A new type of picosecond lifetime measurement system capable of measuring the lifetime of states that decay only by internal conversion was developed and applied to the [sup 186,188]Tl decay tomore » determine the lifetime of the 0[sub 2][sup +] and 2[sub 2][sup +] deformed states in [sup 186,188]Hg. A search for the population of superdeformed states in [sup 192]Hg by the radioactive decay of [sup 192]Tl was accomplished by using a prototype internal pair formation spectrometer.« less

94 β-Decay Half-Lives of Neutron-Rich _{55}Cs to _{67}Ho: Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation.

PubMed

Wu, J; Nishimura, S; Lorusso, G; Möller, P; Ideguchi, E; Regan, P-H; Simpson, G S; Söderström, P-A; Walker, P M; Watanabe, H; Xu, Z Y; Baba, H; Browne, F; Daido, R; Doornenbal, P; Fang, Y F; Gey, G; Isobe, T; Lee, P S; Liu, J J; Li, Z; Korkulu, Z; Patel, Z; Phong, V; Rice, S; Sakurai, H; Sinclair, L; Sumikama, T; Tanaka, M; Yagi, A; Ye, Y L; Yokoyama, R; Zhang, G X; Alharbi, T; Aoi, N; Bello Garrote, F L; Benzoni, G; Bruce, A M; Carroll, R J; Chae, K Y; Dombradi, Z; Estrade, A; Gottardo, A; Griffin, C J; Kanaoka, H; Kojouharov, I; Kondev, F G; Kubono, S; Kurz, N; Kuti, I; Lalkovski, S; Lane, G J; Lee, E J; Lokotko, T; Lotay, G; Moon, C-B; Nishibata, H; Nishizuka, I; Nita, C R; Odahara, A; Podolyák, Zs; Roberts, O J; Schaffner, H; Shand, C; Taprogge, J; Terashima, S; Vajta, Z; Yoshida, S

2017-02-17

The β-decay half-lives of 94 neutron-rich nuclei ^{144-151}Cs, ^{146-154}Ba, ^{148-156}La, ^{150-158}Ce, ^{153-160}Pr, ^{156-162}Nd, ^{159-163}Pm, ^{160-166}Sm, ^{161-168}Eu, ^{165-170}Gd, ^{166-172}Tb, ^{169-173}Dy, ^{172-175}Ho, and two isomeric states ^{174m}Er, ^{172m}Dy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β-decay half-lives are observed at neutron-number N=97 for _{58}Ce, _{59}Pr, _{60}Nd, and _{62}Sm, and N=105 for _{63}Eu, _{64}Gd, _{65}Tb, and _{66}Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

Nuclide Guide and International Chart of Nuclides - 2008

NASA Astrophysics Data System (ADS)

Golashvili, T.

2009-08-01

New versions of Nuclide Guide and Chart of the Nuclides were developed as a result of Russian-Chinese collaboration. The Nuclide Guide contains the basic information on more than 3000 radioactive and stable nuclides. The characteristics of isomers with half-lives more than 1 ms are included. For each nuclide spin, parity, mass of nuclide, magnetic moment (if available), mass excess, half-life or abundance, decay modes, branching ratios, emitted particles, energies of most intense gamma-rays and their intensities, decay energies and mean values of radiation energy per decay are given. For stable and natural long-lived nuclides cross-sections of thermal neutron induced activation are indicated. The information presented in the Guide was compiled from 5 sources: 1) ENSDF-2008, 2) atomic mass evaluation-2005 by Audi and Wapstra, 3) interactive data bases at web-sites , , 4) original evaluations of authors, 5) recent publications. The International Chart ot Nuclides was developed on the basis of information presented in Nuclide Guide.

Investigation of 124Xe nuclear structure with the 8Pi spectrometer at TRIUMF-ISAC

NASA Astrophysics Data System (ADS)

Radich, Allison; Garrett, P.; Jigmeddorj, B.; Michetti-Wilson, J.; Diaz Varela, A.; Hadinia, B.; Bianco, L.; Wong, J.; Chagnon-Lessard, S.; Dunlop, R.; Finlay, P.; Laffoley, A.; Leach, K. G.; Rand, E.; Sumithrarachchi, C.; Svennson, C. E.; Wood, J. L.; Yates, S. W.; Andreoiu, C.; Starosta, K.; Cross, D.; Garnsworthy, A. B.; Hackman, G.; Ball, G.; Triambak, S.

2013-10-01

The 124Xe nucleus has been thought to obey O(6) symmetry but a recent Coulomb excitation study has found that while O(5) may be preserved, O(6) appears to be badly broken. To further characterize the structure of this nucleus, a beta-decay experiment was performed at the TRIUMF-ISAC facility. A beam of radioactive 124Cs at a rate of 9.8 × 107 ions/s was implanted at the center of the 8Pi spectrometer where it underwent β + /EC decay into stable 124Xe. High-statistics gamma-gamma coincidence measurements have been analyzed to add to the level scheme of 124Xe, which has been extended considerably. The high statistics data set has revealed a new decay branch from a 124Cs high-spin isomer as well as several very-weak transitions between low-spin states in 124Xe. Branching ratios and B(E2) transition strengths have been calculated for the updated level scheme. The results will be important in determining collective properties and nuclear structure of the 124Xe.

Synthesis of Superheavy Nuclei in 48CA-INDUCED Reactions

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Voinov, A. A.; Gulbekian, G. G.; Bogomolov, S. L.; Gikal, B. N.; Mezentsev, A. N.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Subotic, K.; Zagrebaev, V. I.; Vostokin, G. K.; Itkis, M. G.; Moody, K. J.; Patin, J. B.; Shaughnessy, D. A.; Stoyer, M. A.; Stoyer, N. J.; Wilk, P. A.; Kenneally, J. M.; Landrum, J. H.; Wild, J. F.; Lougheed, R. W.

2008-11-01

Thirty-four new nuclides with Z = 104-116, 118 and N = 161-177 have been synthesized in the complete-fusion reactions of 238U, 237Np, 242,244Pu, 243Am, 245,248Cm, and 249Cf targets with 48Ca beams. The masses of evaporation residues were identified through measurements of the excitation functions of the xn-evaporation channels and from cross bombardments. The decay properties of the new nuclei agree with those of previously known heavy nuclei and with predictions from different theoretical models. A discussion of self-consistent interpretations of all observed decay chains originating from the parent isotopes 282,283112, 282113, 286-289114, 287,288115, 290-293116, and 294118 is presented. Decay energies and lifetimes of the neutron-rich superheavy nuclei as well as their production cross sections indicate a considerable increase in the stability of nuclei with an increasing number of neutrons, which agrees with the predictions of theoretical models concerning the decisive dependence of the structure and radioactive properties of superheavy elements on their proximity to the nuclear shells with N = 184 and Z = 114.

Study of the 249-251Cf + 48Ca reactions: recent results and outlook

NASA Astrophysics Data System (ADS)

Voinov, A. A.; Oganessian, Yu Ts; Abdullin, F. Sh; Brewer, N. T.; Dmitriev, S. N.; Grzywacz, R. K.; Hamilton, J. H.; Itkis, M. G.; Miernik, K.; Polyakov, A. N.; Roberto, J. B.; Rykaczewski, K. P.; Sabelnikov, A. V.; Sagaidak, R. N.; Shirokovsky, I. V.; Shumeiko, M. V.; Stoyer, M. A.; Subbotin, V. G.; Sukhov, A. M.; Tsyganov, Yu S.; Utyonkov, V. K.; Vostokin, G. K.

2018-02-01

Experiment aiming at the synthesis of heavy isotopes of Z=118 (Og) using beam of 48Ca and a target of 249-251Cf was undertaken in October 2015 - April 2016 employing the Dubna Gas-Filled Recoil Separator (FLNR JINR). The target of mixed isotopes of 249-251Cf (50.7% of 249Cf, 12.9% of 250Cf, and 36.4% of 251Cf) was irradiated by 48Ca ions at two beam energies of 252 and 258 MeV with the corresponding accumulated beam doses of 1.6×1019 and 1.1×1019. A single event observed at lower beam energy was assigned to the isotope 294Og, the product of the reaction 249Cf(48Ca, 3n); its decay pattern and the observed radioactive properties of the nuclides in the decay chain reproduce in full those observed for 294Og in our earlier experiments of 2002-2005 and 2012. At higher beam energy we observed no decay chains that could be attributed to the isotopes of Og. The possibility of renewal of this experiment in the future is discussed.

Isomer spectroscopy of neutron-rich $$^{165,167}$$Tb

DOE PAGES

Gurgi, L. A.; Regan, P. H.; Soderstrom, P. -A.; ...

2017-01-01

We present information on the excited states in the prolate-deformed, neutron-rich nuclei 165,167Tb 100,102. The nuclei of interest were synthesised following in-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm 9Be target at the Radioactive Ion-Beam Factory (RIBF), RIKEN, Japan. The exotic nuclei were separated and identified event-by-event using the BigRIPS separator, with discrete energy gamma-ray decays from isomeric states with half-lives in the μs regime measured using the EURICA gamma-ray spectrometer. Metastable-state decays are identified in 165Tb and 167Tb and interpreted as arising from hindered E1 decay from the 72 –[523] single quasi-protonmore » Nilsson configuration to rotational states built on the 32 –[411] single quasi-proton ground state. Lastly, these data correspond to the first spectroscopic information in the heaviest, odd-A terbium isotopes reported to date and provide information on proton Nilsson configurations which reside close to the Fermi surface as the 170Dy doubly-midshell nucleus is approached.« less

TeO$$_2$$ bolometers with Cherenkov signal tagging: towards next-generation neutrinoless double-beta decay experiments

DOE PAGES

Casali, N.; Vignati, Marco; Beeman, J. W.; ...

2015-01-14

CUORE, an array of 988 TeOmore » $$_2$$ bolometers, is about to be one of the most sensitive experiments searching for neutrinoless double-beta decay. Its sensitivity could be further improved by removing the background from α radioactivity. A few years ago it was pointed out that the signal from βs can be tagged by detecting the emitted Cherenkov light, which is not produced by αs. In this paper we confirm this possibility. For the first time we measured the Cherenkov light emitted by a CUORE crystal, and found it to be 100 eV at the Q-value of the decay. To completely reject the α background, we compute that one needs light detectors with baseline noise below 20 eV RMS, a value which is 3–4 times smaller than the average noise of the bolometric light detectors we are using. We point out that an improved light detector technology must be developed to obtain TeO$$_2$$ bolometric experiments able to probe the inverted hierarchy of neutrino masses.« less

Solute transport in a single fracture involving an arbitrary length decay chain with rock matrix comprising different geological layers.

PubMed

Mahmoudzadeh, Batoul; Liu, Longcheng; Moreno, Luis; Neretnieks, Ivars

2014-08-01

A model is developed to describe solute transport and retention in fractured rocks. It accounts for advection along the fracture, molecular diffusion from the fracture to the rock matrix composed of several geological layers, adsorption on the fracture surface, adsorption in the rock matrix layers and radioactive decay-chains. The analytical solution, obtained for the Laplace-transformed concentration at the outlet of the flowing channel, can conveniently be transformed back to the time domain by the use of the de Hoog algorithm. This allows one to readily include it into a fracture network model or a channel network model to predict nuclide transport through channels in heterogeneous fractured media consisting of an arbitrary number of rock units with piecewise constant properties. More importantly, the simulations made in this study recommend that it is necessary to account for decay-chains and also rock matrix comprising at least two different geological layers, if justified, in safety and performance assessment of the repositories for spent nuclear fuel. Copyright © 2014 Elsevier B.V. All rights reserved.

The interference of medical radionuclides with occupational in vivo gamma spectrometry.

PubMed

Kol, R; Pelled, O; Canfi, A; Gilad, Y; German, U; Laichter, Y; Lantsberg, S; Fuksbrauner, R; Gold, B

2003-06-01

Radiation workers undergo routine monitoring for the evaluation of external and internal radiation exposures. The monitoring of internal exposures involves gamma spectrometry of the whole body (whole body counting) and measurements of excreta samples. Medical procedures involving internal administration of radioactive radionuclides are widely and commonly used. Medical radionuclides are typically short-lived, but high activities are generally administered, whereas occupational radionuclides are mostly long-lived and, if present, are found generally in relatively smaller quantities. The aim of the present work was to study the interference of some common medical radionuclides (201Tl, 9mTc, 57Co, and 131I) with the detection of internal occupational exposures to natural uranium and to 137Cs. Workers having undergone a medical procedure with one of the radionuclides mentioned above were asked to give frequent urine samples and to undergo whole body and thyroid counting with phoswich detectors operated at the Nuclear Research Center Negev. Urine and whole body counting monitoring were continued as long as radioactivity was detectable by gamma spectrometry. The results indicate that the activity of medical radionuclides may interfere with interpretation of occupational intakes for months after administration.

Detecting the Neutrino

NASA Astrophysics Data System (ADS)

Arns, Robert G.

In 1930 Wolfgang Pauli suggested that a new particle might be required to make sense of the radioactive-disintegration mode known as beta decay. This conjecture initially seemed impossible to verify since the new particle, which became known as the neutrino, was uncharged, had zero or small mass, and interacted only insignificantly with other matter. In 1951 Frederick Reines and Clyde L. Cowan, Jr., of the Los Alamos Scientific Laboratory undertook the difficult task of detecting the free neutrino by observing its inverse beta-decay interaction with matter. They succeeded in 1956. The neutrino was accepted rapidly as a fundamental particle despite discrepancies in reported details of the experiments and despite the absence of independent verification of the result. This paper describes the experiments, examines the nature of the discrepancies, and discusses the circumstances of the acceptance of the neutrino's detection by the physics community.

Modeling surface backgrounds from radon progeny plate-out

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perumpilly, G.; Guiseppe, V. E.; Snyder, N.

2013-08-08

The next generation low-background detectors operating deep underground aim for unprecedented low levels of radioactive backgrounds. The surface deposition and subsequent implantation of radon progeny in detector materials will be a source of energetic background events. We investigate Monte Carlo and model-based simulations to understand the surface implantation profile of radon progeny. Depending on the material and region of interest of a rare event search, these partial energy depositions can be problematic. Motivated by the use of Ge crystals for the detection of neutrinoless double-beta decay, we wish to understand the detector response of surface backgrounds from radon progeny. Wemore » look at the simulation of surface decays using a validated implantation distribution based on nuclear recoils and a realistic surface texture. Results of the simulations and measured α spectra are presented.« less

Observation of a γ-decaying millisecond isomeric state in 128Cd80

NASA Astrophysics Data System (ADS)

Jungclaus, A.; Grawe, H.; Nishimura, S.; Doornenbal, P.; Lorusso, G.; Simpson, G. S.; Söderström, P.-A.; Sumikama, T.; Taprogge, J.; Xu, Z. Y.; Baba, H.; Browne, F.; Fukuda, N.; Gernhäuser, R.; Gey, G.; Inabe, N.; Isobe, T.; Jung, H. S.; Kameda, D.; Kim, G. D.; Kim, Y.-K.; Kojouharov, I.; Kubo, T.; Kurz, N.; Kwon, Y. K.; Li, Z.; Sakurai, H.; Schaffner, H.; Shimizu, Y.; Steiger, K.; Suzuki, H.; Takeda, H.; Vajta, Zs.; Watanabe, H.; Wu, J.; Yagi, A.; Yoshinaga, K.; Benzoni, G.; Bönig, S.; Chae, K. Y.; Coraggio, L.; Daugas, J.-M.; Drouet, F.; Gadea, A.; Gargano, A.; Ilieva, S.; Itaco, N.; Kondev, F. G.; Kröll, T.; Lane, G. J.; Montaner-Pizá, A.; Moschner, K.; Mücher, D.; Naqvi, F.; Niikura, M.; Nishibata, H.; Odahara, A.; Orlandi, R.; Patel, Z.; Podolyák, Zs.; Wendt, A.

2017-09-01

A new high-spin isomer in the neutron-rich nucleus 128Cd was populated in the projectile fission of a 238U beam at the Radioactive Isotope Beam Factory at RIKEN. A half-life of T1/2 = 6.3 (8) ms was measured for the new state which was tentatively assigned a spin/parity of (15-). The experimental results are compared to shell model calculations performed using state-of-the-art realistic effective interactions and to the neighbouring nucleus 129Cd. In the present experiment no evidence was found for the decay of a 18+E6 spin-trap isomer, based on the complete alignment of the two-neutron and two-proton holes in the 0h11/2 and the 0g9/2 orbit, respectively, which is predicted to exist by the shell model.

Radiocarbon Dating, Memories, and Hopes

DOE R&D Accomplishments Database

Libby, W. F.

1972-10-01

The history of radiocarbon dating from 1939 to the present is reviewed. The basic principles of radiocarbon dating are that cosmic rays make living things radioactive with {sup 14}C to a certain level fixed by the environment and that at death the intake of food stops so no replenishment of the {sup 14}C steadily lost by the immutable decay occurs. Therefore measurement of the degree of decay gives the time lapse since death, i.e., the radiocarbon age. The equipment developed and experiments performed to measure the specific activity of specimens to be dated are described. The results obtained by world-wide experimenters are discussed. These showed that on simultaneity radiocarbon dating is apparently reliable but that absolute dates may be incorrect by as much as 600 to 700 y. The value of radiocarbon dating to archaeologists, geologists, climatologists, and historians is stressed. (LCL)

Development of New High Resolution Neutron Detector

NASA Astrophysics Data System (ADS)

Mostella, L. D., III; Rajabali, M.; Loureiro, D. P.; Grzywacz, R.

2017-09-01

Beta-delayed neutron emission is a prevalent form of decay for neutron-rich nuclei. This occurs when an unstable nucleus undergoes beta decay, but produces a daughter nucleus in an excited state above the neutron separation energy. The daughter nucleus then de-excites by ejecting one or more neutrons. We wish to map the states from which these nuclei decay via neutron spectroscopy using NEXT, a new high resolution neutron detector. NEXT utilizes silicon photomultipliers and 6 mm thick pulse-shape discriminating plastic scintillators, allowing for smaller and more compact modular geometries in the NEXT array. Timing measurements for the detector were performed and a resolution of 893 ps (FWHM) has been achieved so far. Aspects of the detector that were investigated and will be presented here include scintillator geometry, wrapping materials, fitting functions for the digitized signals, and electronic components coupled to the silicon photomultipliers for signal shaping.

Fourier heat conduction as a strong kinetic effect in one-dimensional hard-core gases

NASA Astrophysics Data System (ADS)

Zhao, Hanqing; Wang, Wen-ge

2018-01-01

For a one-dimensional (1D) momentum conserving system, intensive studies have shown that generally its heat current autocorrelation function (HCAF) tends to decay in a power-law manner and results in the breakdown of the Fourier heat conduction law in the thermodynamic limit. This has been recognized to be a dominant hydrodynamic effect. Here we show that, instead, the kinetic effect can be dominant in some cases and leads to the Fourier law for finite-size systems. Usually the HCAF undergoes a fast decaying kinetic stage followed by a long slowly decaying hydrodynamic tail. In a finite range of the system size, we find that whether the system follows the Fourier law depends on whether the kinetic stage dominates. Our Rapid Communication is illustrated by the 1D hard-core gas models with which the HCAF is derived analytically and verified numerically by molecular dynamics simulations.

Simultaneous measurement of the maximum oscillation amplitude and the transient decay time constant of the QCM reveals stiffness changes of the adlayer.

PubMed

Marxer, C Galli; Coen, M Collaud; Bissig, H; Greber, U F; Schlapbach, L

2003-10-01

Interpretation of adsorption kinetics measured with a quartz crystal microbalance (QCM) can be difficult for adlayers undergoing modification of their mechanical properties. We have studied the behavior of the oscillation amplitude, A(0), and the decay time constant, tau, of quartz during adsorption of proteins and cells, by use of a home-made QCM. We are able to measure simultaneously the frequency, f, the dissipation factor, D, the maximum amplitude, A(0), and the transient decay time constant, tau, every 300 ms in liquid, gaseous, or vacuum environments. This analysis enables adsorption and modification of liquid/mass properties to be distinguished. Moreover the surface coverage and the stiffness of the adlayer can be estimated. These improvements promise to increase the appeal of QCM methodology for any applications measuring intimate contact of a dynamic material with a solid surface.

Management of thyroid carcinoma with radioactive 131I.

PubMed

Paryani, S B; Chobe, R J; Scott, W; Wells, J; Johnson, D; Kuruvilla, A; Schoeppel, S; Deshmukh, A; Miller, R; Dajani, L; Montgomery, C T; Puestow, E; Purcell, J; Roura, M; Sutton, D; Mallett, R; Peer, J

1996-08-01

To evaluate the role of radioactive 131I in the management of patients with well differentiated carcinoma of the thyroid. Between 1965 and 1995, a total of 117 patients with well-differentiated carcinoma of the thyroid underwent either lobectomy or thyroidectomy followed by 100-150 mCi of 131I. With a median follow-up of 8 years, only four patients (3%) developed a recurrence of their disease. The 5-year actuarial survival was 97% with a 10-year survival of 91%. There were no severe side effects noted after 131I therapy. Radioactive 131I is a safe and effective procedure for the majority of patients with well-differentiated thyroid carcinoma. We currently recommend that all patients undergo a subtotal or total thyroidectomy followed by 131I thyroid scanning approximately 4 weeks after surgery. If the thyroid scan shows no residual uptake and all disease is confined to the thyroid, we recommend following patients with annual thyroid scans and serum thyroglobulin levels. If there is any residual uptake detected in the neck or if the tumor extends beyond the thyroid, we recommend routine thyroid ablation of 100-150 mCi of radioactive 131I.

High Precision 40K/39K Ratio Determination

NASA Astrophysics Data System (ADS)

Naumenko, M. O.; Mezger, K.; Nagler, T. F.; Villa, I. M.

2012-12-01

Potassium is one of the eight most abundant chemical elements in the Earth's crust and a major element in many rock-forming minerals. The isotope 40K is radioactive and undergoes β- decay to 40Ca (ca. 89.3%) and electron capture to 40Ar (ca. 10.7%). Both decays can potentially be used as dating systems. The most commonly used branch is the decay of 40K to 40Ar because it can yield highly precise ages. Both decay schemes rely on the knowledge of the 40K branching ratio and the natural 40K abundance. A 40K abundance of 0.011672±41 % was measured on terrestrial material [1]. The relative uncertainty of 0.35 % has not been improved since. Recent improvements in the precision of mass spectrometric measurements have led to the situation that the uncertainties on the K decay constant and the abundance of 40K are a major source of uncertainty on the measured ages. A more precise definition of the 40K decay constant was attempted by different research groups within the last decade [2-9] but the goal of obtaining 0.1 % relative uncertainty on K-Ar ages for geological materials, as requested by the EARTHtime initiative, has not been achieved yet. In order to improve on this situation we studied the abundances of the K isotopes in terrestrial standards. A ThermoFischer Triton+ thermal ionisation mass spectrometer was used for K isotope ratio measurements of the NIST SRM 918b K standard loaded on Ta filaments with 0.1M phosphoric acid. Three techniques were applied: (A) dynamic measurement with in-run normalisation to the IUPAC value 41K/39K=0.072168; (B) a simple total evaporation procedure; (C) the "NBL-modified" total evaporation [10]. The 40K ion beam was measured in a Faraday cup with a 1E12 Ω resistor; 39K and 41K were collected in Faraday cups with 1E11 Ω resistors. Amplifier gains were intercalibrated by supplying fixed voltages off-line. Different measurement techniques were combined with different loading procedures. We also tested ionisation yields for the evaporation procedures (B) and (C). Our measured 40K/39K ratios are statistically indistinguishable from those reported by [1] but have lower uncertainties. Techniques A, B and C gave 1 standard error of 0.07 %, 0.2 %, and 0.14 %, respectively. 1. Garner E.L. et al. (1975) J.Res.Natl.Bur.Stand.79A, 713-725. 2. Grau Malonda A., Grau Carles A. (2002) Appl. Radiat. Isot. 56, 153-156. 3. Kossert K., Günter E. (2004) Appl.Radiat.Isot.60, 459-464. 4. Krumrei T.V. et al. (2006) Chem.Geol. 227, 258-273. 5. Kwon J. et al. (2002) Math.Geol. 34, 457-475. 6. Min K. et al. (2000) Geochim. Cosmochim. Acta 64, 73-98. 7. Nägler T.F., Villa I.M. (2000) Chem. Geol. 169, 5-16. 8. Renne P.R. et al. (2010) Geochim. Cosmochim. Acta 74, 5349-5367. 9. Schwarz W.H. et al. (2011) Geochim. Cosmochim. Acta 75, 5094-5096. 10. Richter S., Goldberg S.A. (2003) Int. J. Mass Spect. 229, 181-197.