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Sample records for atomic radiation unscear

  1. The birth of UNSCEAR--the midwife's tale.

    PubMed

    Appleyard, Ray

    2010-09-01

    The creation in 1955 of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was driven by the potential dangers of worldwide radioactive fall-out from the testing of nuclear bombs: both a cold war political issue and a complex radiological problem. Sir Raymond Appleyard was Secretary of the UNSCEAR Committee from 1956 to 1961, linking the Committee and its delegations with the UN as host institution and with the other members of the Committee's scientific staff. The present reflections are his purely personal views and memories of incidents and people during the Committee's formative years. They complement Dr David Sowby's earlier recollections (Sowby 2008 J. Radiol. Prot. 28 271-6). PMID:20826894

  2. Medical exposure assessment: the global approach of the United Nations Scientific Committee on the Effects of Atomic Radiation.

    PubMed

    Shannoun, F

    2015-07-01

    The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was established in 1955 to systematically collect, evaluate, publish and share data on the global levels and effects of ionizing radiation from natural and artificial sources. Regular surveys have been conducted to determinate the frequencies of medical radiological procedure, the number of equipment and staffing and the level of global exposure using the health care level (HCL) extrapolation model. UNSCEAR surveys revealed a range of issues relating to participation, survey process, data quality and analysis. Thus, UNSCEAR developed an improvement strategy to address the existing deficiencies in data quality and collection. The major element of this strategy is the introduction of an on-line platform to facilitate the data collection and archiving process. It is anticipated that the number of countries participating in UNSCEAR's surveys will increase in the future, particularly from HCL II-IV countries.

  3. A comparison of radiological risk assessment models: Risk assessment models used by the BEIR V Committee, UNSCEAR, ICRP, and EPA (for NESHAP)

    SciTech Connect

    Wahl, L.E.

    1994-03-01

    Radiological risk assessments and resulting risk estimates have been developed by numerous national and international organizations, including the National Research Council`s fifth Committee on the Biological Effects of Ionizing Radiations (BEIR V), the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), and the International Commission on Radiological Protection (ICRP). A fourth organization, the Environmental Protection Agency (EPA), has also performed a risk assessment as a basis for the National Emission Standards for Hazardous Air Pollutants (NESHAP). This paper compares the EPA`s model of risk assessment with the models used by the BEIR V Committee, UNSCEAR, and ICRP. Comparison is made of the values chosen by each organization for several model parameters: populations used in studies and population transfer coefficients, dose-response curves and dose-rate effects, risk projection methods, and risk estimates. This comparison suggests that the EPA has based its risk assessment on outdated information and that the organization should consider adopting the method used by the BEIR V Committee, UNSCEAR, or ICRP.

  4. Resonance Radiation and Excited Atoms

    NASA Astrophysics Data System (ADS)

    Mitchell, Allan C. G.; Zemansky, Mark W.

    2009-06-01

    1. Introduction; 2. Physical and chemical effects connected with resonance radiation; 3. Absorption lines and measurements of the lifetime of the resonance state; 4. Collision processes involving excited atoms; 5. The polarization of resonance radiation; Appendix; Index.

  5. Thoron and decay products, beyond UNSCEAR 2006 Annex E.

    PubMed

    Chambers, D B

    2010-10-01

    Uranium and thorium series radionuclides are present in all soils and rocks. Thus, radon and thoron, the radioactive noble gases originating in the uranium ((238)U) and thorium ((232)Th) decay chains is ubiquitous and everyone is exposed to both radon and thoron gases and their particulate radioactive decay products. As described in UNSCEAR Annex E (2006), radon and its decay products have been recognised for many years as a hazard to underground miners. More recently, the risks from exposure to residential radon have been demonstrated through residential case-control epidemiological studies. However, as discussed by UNSCEAR, exposures to thoron and its decay products have often been relatively ignored. Moreover, unlike radon the effects of exposure to thoron and its decay products are not available from epidemiology and thus, a dosimetric approach is required to assess risks. UNSCEAR continues to recommend the use of a dose conversion factor for thoron decay products of 40 nSv (Bq h m(-3))(-1). UNSCEAR Annex E suggests there is an emerging problem, namely, that the contribution of (220)Rn (thoron) gas to the (222)Rn (radon) gas measurement signal is not well known. Until recently, this has largely been ignored. This is an important consideration as measurements at work and homes are the basis for investigating lung cancer exposure-response relationships. Based on UNSCEAR Annex E, this paper provides an overview of the sources and levels of thoron and its associated decay products at home and work. In addition, this paper provides an overview of the thoron dosimetry considered by UNSCEAR Annex E and some recent results.

  6. Electrical Analogs of Atomic Radiative Decay Processes

    ERIC Educational Resources Information Center

    Fontana, Peter R.; Srivastava, Rajendra P.

    1977-01-01

    Analyzes simple electrical circuits, showing that for high frequencies they have frequency and time responses identical to the spontaneous radiative decay of atoms. Compares a two-circuit electrical system with a two-level atom. (MLH)

  7. Radiative vacancies decay of endohedral atoms

    NASA Astrophysics Data System (ADS)

    Amusia, Miron; Baltenkov, Arkadiy

    2006-05-01

    It is demonstrated that the fulleren shell affects dramatically the radiative vacancy decay of an endohedral atom A@C60. It also adds new possibilities to radiative and non-radiative decay by opening a number of new interchannel decays similar to that in ordinary atoms where initial and final state vacancies almost always belong to different subshells. We demonstrate that the radiative width of a vacancy decay due to electron transition in the atom A in A@C60 acquire an additional factor that can be expressed via the polarizability of the C60 at transition energy. In general, it can not only enhance but also totally lock the radiative decay channel. For vacancies in subvalent shells of noble gas atoms N the non-radiative decay is forbidden. For N@C60 this decay is allowed since can proceed due to transition of fulleren shell electron to the vacancy in N. Corresponding width is expressed via the C60 total photoabsorption cross-section at the transition energy.

  8. Radium equivalent activity in the light of UNSCEAR report.

    PubMed

    Tufail, Muhammad

    2012-09-01

    Radium equivalent activity (Ra ( eq )) has been in practice for the last 40 years for the assessment of radiological hazard of radioactivity in environmental materials. The in-practice model for the calculation of the Ra ( eq ) has been critically reviewed in the light of the UNSCEAR 2000 report. Annual effective dose (E) values of (232)Th and (40)K were found to be not equal to that of (226)Ra derived from the activity concentrations of these radionuclides used in the expression for the Ra ( eq ). Therefore, a modified model has been proposed for the determination of the Ra ( eq ) for outdoor external exposure to gamma rays. The relation between the E and Ra ( eq ) has been explored. It is recommended that while describing the radiological hazard of the materials containing radioactivity, there should be no need to calculate the Ra ( eq ) if the E has already been determined or vice versa.

  9. Classical helium atom with radiation reaction

    SciTech Connect

    Camelio, G.; Carati, A.; Galgani, L.

    2012-06-15

    We study a classical model of helium atom in which, in addition to the Coulomb forces, the radiation reaction forces are taken into account. This modification brings in the model a new qualitative feature of a global character. Indeed, as pointed out by Dirac, in any model of classical electrodynamics of point particles involving radiation reaction one has to eliminate, from the a priori conceivable solutions of the problem, those corresponding to the emission of an infinite amount of energy. We show that the Dirac prescription solves a problem of inconsistency plaguing all available models which neglect radiation reaction, namely, the fact that in all such models, most initial data lead to a spontaneous breakdown of the atom. A further modification is that the system thus acquires a peculiar form of dissipation. In particular, this makes attractive an invariant manifold of special physical interest, the zero-dipole manifold that corresponds to motions in which no energy is radiated away (in the dipole approximation). We finally study numerically the invariant measure naturally induced by the time-evolution on such a manifold, and this corresponds to studying the formation process of the atom. Indications are given that such a measure may be singular with respect to that of Lebesgue.

  10. Classical helium atom with radiation reaction.

    PubMed

    Camelio, G; Carati, A; Galgani, L

    2012-06-01

    We study a classical model of helium atom in which, in addition to the Coulomb forces, the radiation reaction forces are taken into account. This modification brings in the model a new qualitative feature of a global character. Indeed, as pointed out by Dirac, in any model of classical electrodynamics of point particles involving radiation reaction one has to eliminate, from the a priori conceivable solutions of the problem, those corresponding to the emission of an infinite amount of energy. We show that the Dirac prescription solves a problem of inconsistency plaguing all available models which neglect radiation reaction, namely, the fact that in all such models, most initial data lead to a spontaneous breakdown of the atom. A further modification is that the system thus acquires a peculiar form of dissipation. In particular, this makes attractive an invariant manifold of special physical interest, the zero-dipole manifold that corresponds to motions in which no energy is radiated away (in the dipole approximation). We finally study numerically the invariant measure naturally induced by the time-evolution on such a manifold, and this corresponds to studying the formation process of the atom. Indications are given that such a measure may be singular with respect to that of Lebesgue.

  11. Blackbody radiation shifts in optical atomic clocks.

    PubMed

    Safronova, Marianna; Kozlov, Mikhail; Clark, Charles

    2012-03-01

    A review of recent theoretical calculations of blackbody radiation (BBR) shifts in optical atomic clocks is presented. We summarize previous results for monovalent ions that were obtained by a relativistic all-order single-double method, where all single and double excitations of the Dirac- Fock wave function are included to all orders of perturbation theory. A recently developed method for accurate calculations of BBR shifts in divalent atoms is then presented. This approach combines the relativistic all-order method and the configuration interaction method, which provides for accurate treatment of correlation corrections in atoms with two valence electrons. Calculations of the BBR shifts in B+, Al+, and In+ have enabled us to reduce the present fractional uncertainties in the frequencies of their clock transitions as measured at room temperature: to 4 × 10-19 for Al+ and 10-18 for B+ and In+. These uncertainties approach recent estimates of the limits of precision of currently proposed optical atomic clocks. We discuss directions of future theoretical developments for reducing clock uncertainties resulting from blackbody radiation shifts.

  12. Blackbody radiation shifts in optical atomic clocks.

    PubMed

    Safronova, Marianna; Kozlov, Mikhail; Clark, Charles

    2012-03-01

    A review of recent theoretical calculations of blackbody radiation (BBR) shifts in optical atomic clocks is presented. We summarize previous results for monovalent ions that were obtained by a relativistic all-order single-double method, where all single and double excitations of the Dirac- Fock wave function are included to all orders of perturbation theory. A recently developed method for accurate calculations of BBR shifts in divalent atoms is then presented. This approach combines the relativistic all-order method and the configuration interaction method, which provides for accurate treatment of correlation corrections in atoms with two valence electrons. Calculations of the BBR shifts in B+, Al+, and In+ have enabled us to reduce the present fractional uncertainties in the frequencies of their clock transitions as measured at room temperature: to 4 × 10-19 for Al+ and 10-18 for B+ and In+. These uncertainties approach recent estimates of the limits of precision of currently proposed optical atomic clocks. We discuss directions of future theoretical developments for reducing clock uncertainties resulting from blackbody radiation shifts. PMID:22481777

  13. New dosimetry of atomic bomb radiations.

    PubMed

    Fry, R J; Sinclair, W K

    1987-10-10

    The reassessment of the radiation dosimetry from the Hiroshima and Nagasaki atomic bombs is almost complete. Since atomic bomb survivors provide a major source of data for estimates of risk of cancer induction by radiation the impact of the new dosimetry on risk estimates and radiation protection standards is important. The changes include an increase of about 20% in the estimated yield of the Hiroshima bomb and a reduction in the estimated doses from neutrons in both cities. The estimated neutron dose for Hiroshima is about 10% of the previous estimate. The neutron doses are now so small that direct estimates of neutron relative biological effectiveness may be precluded or be much more difficult. There is little change in most of the gamma ray organ doses because various changes in the new estimates tend to cancel each other out. The new estimate of the attenuation of the free-in-air kerma by the walls of the homes is about twice that used in the previous dosimetry. But the transmission of gamma radiation to the deep organs such as bone marrow is significantly greater than earlier estimates. Probably future risk estimates for radiogenic cancer will be somewhat higher because of both the new dosimetry and the new cancer mortality data. New risk estimates should be available in 1988.

  14. Radon releases from Australian uranium mining and milling projects: assessing the UNSCEAR approach.

    PubMed

    Mudd, Gavin M

    2008-02-01

    The release of radon gas and progeny from the mining and milling of uranium-bearing ores has long been recognised as a potential radiological health hazard. The standards for exposure to radon and progeny have decreased over time as the understanding of their health risk has improved. In recent years there has been debate on the long-term releases (10,000 years) of radon from uranium mining and milling sites, focusing on abandoned, operational and rehabilitated sites. The primary purpose has been estimates of the radiation exposure of both local and global populations. Although there has been an increasing number of radon release studies over recent years in the USA, Australia, Canada and elsewhere, a systematic evaluation of this work has yet to be published in the international literature. This paper presents a detailed compilation and analysis of Australian studies. In order to quantify radon sources, a review of data on uranium mining and milling wastes in Australia, as they influence radon releases, is presented. An extensive compilation of the available radon release data is then assembled for the various projects, including a comparison to predictions of radon behaviour where available. An analysis of cumulative radon releases is then developed and compared to the UNSCEAR approach. The implications for the various assessments of long-term releases of radon are discussed, including aspects such as the need for ongoing monitoring of rehabilitation at uranium mining and milling sites and life-cycle accounting.

  15. Atomic clocks with suppressed blackbody radiation shift.

    PubMed

    Yudin, V I; Taichenachev, A V; Okhapkin, M V; Bagayev, S N; Tamm, Chr; Peik, E; Huntemann, N; Mehlstäubler, T E; Riehle, F

    2011-07-15

    We develop a concept of atomic clocks where the blackbody radiation shift and its fluctuations can be suppressed by 1-3 orders of magnitude independent of the environmental temperature. The suppression is based on the fact that in a system with two accessible clock transitions (with frequencies ν1 and ν2) which are exposed to the same thermal environment, there exists a "synthetic" frequency ν(syn) ∝ (ν1 - ε12ν2) largely immune to the blackbody radiation shift. For example, in the case of 171Yb+ it is possible to create a synthetic-frequency-based clock in which the fractional blackbody radiation shift can be suppressed to the level of 10(-18) in a broad interval near room temperature (300±15  K). We also propose a realization of our method with the use of an optical frequency comb generator stabilized to both frequencies ν1 and ν2, where the frequency ν(syn) is generated as one of the components of the comb spectrum.

  16. Collisional-radiative nonequilibrium in partially ionized atomic nitrogen

    NASA Technical Reports Server (NTRS)

    Kunc, J. A.; Soon, W. H.

    1989-01-01

    A nonlinear collisional-radiative model for determination of nonequilibrium production of electrons, excited atoms, and bound-bound, dielectronic and continuum line intensities in stationary partially ionized atomic nitrogen is presented. Populations of 14 atomic levels and line intensities are calculated in plasma with T(e) = 8000-15,000 K and N(t) = 10 to the 12th - 10 to the 18th/cu cm. Transport of radiation is included by coupling the rate equations of production of the electrons and excited atoms with the radiation escape factors, which are not constant but depend on plasma conditions.

  17. Atomic and molecular science with synchrotron radiation

    SciTech Connect

    Not Available

    1989-11-07

    This paper discusses the following topics: electron correlation in atoms; atomic innershell excitation and decay mechanisms; timing experiments; x-ray scattering; properties of ionized species; electronic properties of actinide atoms; total photon-interaction cross sections; and molecular physics. 66 refs. (LSP)

  18. Space Radiation, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Corliss, William R.

    Described is the protection from space radiation afforded the earth by the atmosphere, ionosphere, and magnetic field. The importance of adequate instruments is emphasized by noting how refinements of radiation detection instruments was necessary for increased understanding of space radiation. The role of controversy and accident in the research…

  19. Atomic photoelectron-spectroscopy studies using synchrotron radiation

    SciTech Connect

    Kobrin, P.H.

    1983-02-01

    Photoelectron spectroscopy combined with tunable synchrotron radiation has been used to study the photoionization process in several atomic systems. The time structure of the synchrotron radiation source at the Stanford Synchrotron Radiation Laboratory (SSRL) was used to record time-of-flight (TOF) photoelectron spectra of gaseous Cd, Hg, Ne, Ar, Ba, and Mn. The use of two TOF analyzers made possible the measurement of photoelectron angular distributions as well as branching ratios and partial cross sections.

  20. Radiation therapy among atomic bomb survivors, Hiroshima and Nagasaki.

    PubMed

    Kato, K; Antoku, S; Russell, W J; Fujita, S; Pinkston, J A; Hayabuchi, N; Hoshi, M; Kodama, K

    1998-06-01

    As a follow-up to the two previous surveys of radiation therapy among the atomic bomb survivors, a large-scale survey was performed to document (1) the number of radiation therapy treatments received by the atomic bomb survivors and (2) the types of radiation treatments conducted in Hiroshima and Nagasaki. The previous two surveys covered the radiation treatments among the Radiation Effects Research Foundation Adult Health Study (AHS) population, which is composed of 20,000 persons. In the present survey, the population was expanded to include the Life Span Study (LSS), including 93,611 atomic bomb survivors and 26,517 Hiroshima and Nagasaki citizens who were not in the cities at the times of the bombings. The LSS population includes the AHS population. The survey was conducted from 1981 to 1984. The survey teams reviewed all the medical records for radiation treatments of 24,266 patients at 11 large hospitals in Hiroshima and Nagasaki. Among them, the medical records for radiation treatments of 1556 LSS members were reviewed in detail. By analyzing the data obtained in the present and previous surveys, the number of patients receiving radiation therapy was estimated to be 4501 (3.7%) in the LSS population and 1026 (5.1%) in the AHS population between 1945-1980. During 1945-1965, 98% of radiation treatments used medium-voltage X rays, and 66% of the treatments were for benign diseases. During 1966-1980, 94% of the radiation treatments were for malignant neoplasms. During this period, 60Co gamma-ray exposure apparatus and high-energy electron accelerators were the prevalent mode of treatment in Hiroshima and in Nagasaki, respectively. The mean frequency of radiation therapy among the LSS population was estimated to have been 158 courses/year during 1945-1965 and 110 courses/year during 1966-1980. The present survey revealed that 377 AHS members received radiation therapy. The number was approximately twice the total number of cases found in the previous two surveys

  1. The Iron Project:. Radiative Atomic Processes in Astrophysics

    NASA Astrophysics Data System (ADS)

    Nahar, Sultana N.

    2011-06-01

    Astronomical objects, such as, stars, galaxies, blackhole environments, etc are studied through their spectra produced by various atomic processes in their plasmas. The positions, shifts, and strengths of the spectral lines provide information on physical processes with elements in all ionization states, and various diagnostics for temperature, density, distance, etc of these objects. With presence of a radiative source, such as a star, the astrophysical plasma is dominated by radiative atomic processes such as photoionization, electron-ion recombination, bound-bound transitions or photo-excitations and de-excitations. The relevant atomic parameters, such as photoionization cross sections, electron-ion recombination rate coefficients, oscillator strengths, radiative transition rates, rates for dielectronic satellite lines etc are needed to be highly accurate for precise diagnostics of physical conditions as well as accurate modeling, such as, for opacities of astrophysical plasmas. for opacities of astrophysical plasmas. This report illustrates detailed features of radiative atomic processes obtained from accurate ab initio methods of the latest developments in theoretical quantum mechanical calculations, especially under the international collaborations known as the Iron Project (IP) and the Opacity Project (OP). These projects aim in accurate study of radiative and collsional atomic processes of all astrophysically abundant atoms and ions, from hydrogen to nickel, and calculate stellar opacities and have resulted in a large number of atomic parameters for photoionization and radiative transition probabilities. The unified method, which is an extension of the OP and the IP, is a self-consistent treatment for the total electron-ion recombination and photoionization. It incorporates both the radiative and the dielectronic recombination processes and provides total recombination rates and level-specific recombination rates for hundreds of levels for a wide range of

  2. Vacuum ultraviolet radiation/atomic oxygen synergism in materials reactivity

    NASA Technical Reports Server (NTRS)

    Koontz, Steven; Leger, Lubert; Albyn, Keith; Cross, Jon

    1990-01-01

    Experimental results are presented which indicate that low fluxes of vacuum UV (VUV) radiation exert a pronounced influence on the atomic oxygen reactivity of such fluorocarbon and fluorocarbon spacecraft materials as the FEP Teflon and PCTFE that are under consideration for the Space Station Freedom. With simultaneous exposure to VUV fluxes comparable to those experienced in LEO, the reactivity of these materials becomes comparable to that of Kapton; VUV radiation has also been shown to increase the reactivity of Kapton with thermal-energy oxygen atoms.

  3. Radiation and cancer risk in atomic-bomb survivors.

    PubMed

    Kodama, K; Ozasa, K; Okubo, T

    2012-03-01

    With the aim of accurately assessing the effects of radiation exposure in the Japanese atomic-bomb survivors, the Radiation Effects Research Foundation has, over several decades, conducted studies of the Life Span Study (LSS) cohort, comprising 93 000 atomic-bomb survivors and 27 000 controls. Solid cancer: the recent report on solid cancer incidence found that at age 70 years following exposure at age 30 years, solid cancer rates increase by about 35%  Gy(-1) for men and 58% Gy(-1) for women. Age-at-exposure is an important risk modifier. In the case of lung cancer, cigarette smoking has been found to be an important risk modifier. Radiation has similar effects on first-primary and second-primary cancer risks. Finally, radiation-associated increases in cancer rates appear to persist throughout life. Leukaemia: the recent report on leukaemia mortality suggests that radiation effects on leukaemia mortality persisted for more than 50 years. Moreover, significant dose-response for myelodysplastic syndrome was observed in Nagasaki LSS members even 40-60 years after radiation exposure. Future perspective: given the continuing solid cancer increase in the survivor population, the LSS will likely continue to provide important new information on radiation exposure and solid cancer risks for another 15-20 years, especially for those exposed at a young age.

  4. Radiation and cancer risk in atomic-bomb survivors.

    PubMed

    Kodama, K; Ozasa, K; Okubo, T

    2012-03-01

    With the aim of accurately assessing the effects of radiation exposure in the Japanese atomic-bomb survivors, the Radiation Effects Research Foundation has, over several decades, conducted studies of the Life Span Study (LSS) cohort, comprising 93 000 atomic-bomb survivors and 27 000 controls. Solid cancer: the recent report on solid cancer incidence found that at age 70 years following exposure at age 30 years, solid cancer rates increase by about 35%  Gy(-1) for men and 58% Gy(-1) for women. Age-at-exposure is an important risk modifier. In the case of lung cancer, cigarette smoking has been found to be an important risk modifier. Radiation has similar effects on first-primary and second-primary cancer risks. Finally, radiation-associated increases in cancer rates appear to persist throughout life. Leukaemia: the recent report on leukaemia mortality suggests that radiation effects on leukaemia mortality persisted for more than 50 years. Moreover, significant dose-response for myelodysplastic syndrome was observed in Nagasaki LSS members even 40-60 years after radiation exposure. Future perspective: given the continuing solid cancer increase in the survivor population, the LSS will likely continue to provide important new information on radiation exposure and solid cancer risks for another 15-20 years, especially for those exposed at a young age. PMID:22394591

  5. Rydberg atom spectroscopy enabled by blackbody radiation ionization

    SciTech Connect

    Lu Xiaoxu; Sun Yuan; Metcalf, Harold

    2011-09-15

    We have excited helium atoms from their metastable 2 {sup 3} S state to Rydberg states in the range 13Atoms in a thermal beam (100 K) cross partially overlapping laser beams of the appropriate frequencies in the counterintuitive order to exploit the high efficiency of stimulated rapid adiabatic passage. The interaction region is between two plates that can be used for Stark tuning in a few V/cm field or for field ionization. At fields much too low for field ionization, we observe signals attributed to ionization by blackbody radiation. Multiple tests confirm this attribution as the cause of ionization. For example, by heating the plates we observe the expected signal increases. Our experiments reinforce previous work where the interaction between Rydberg atoms and room temperature blackbody radiation is important for experiments.

  6. The radiative association of P and O atoms

    NASA Astrophysics Data System (ADS)

    Andreazza, C. M.; de Almeida, A. A.; Borin, A. C.

    2016-04-01

    The formation of PO from the radiative association of phosphorus and oxygen atoms has been estimated by accurate quantum chemistry calculations. The radiative association of P and O atoms along the B2Σ+ potential energy curve is the most efficient way of producing PO in the X2Π ground state. For temperatures ranging between 300 and 14 000 K, the rate coefficients are found to vary from 1.61 × 10-24 to 1.99 × 10-18 cm3s-1, respectively. These values indicate that only a very small amount of PO molecules can be formed by radiative association in dense and hot gas close to the photosphere of evolved oxygen-rich stars and other hostile environments.

  7. Tracing Magnetic Fields by Atomic Alignment in Extended Radiation Fields

    NASA Astrophysics Data System (ADS)

    Zhang, Heshou; Yan, Huirong; Dong, Le

    2015-05-01

    Tracing magnetic field is crucial as magnetic field plays an important role in many astrophysical processes. Earlier studies have demonstrated that ground state alignment (GSA) is an effective way to detect a weak magnetic field (1G≳ B≳ {{10}-15} G) in a diffuse medium. We explore the atomic alignment in the presence of an extended radiation field for both absorption lines and emission lines. The alignment in the circumstellar medium, binary systems, disks, and the local interstellar medium are considered in order to study the alignment in the radiation field where the pumping source has a clear geometric structure. Furthermore, the multipole expansion method is adopted to study GSA induced in the radiation field with unidentified pumping sources. We study the alignment in the dominant radiation components of the general radiation field: the dipole and quadrupole radiation field. We discuss the approximation of GSA in a general radiation field by summing the contribution from the dipole and quadrupole radiation field. We conclude that GSA is a powerful tool for detecting weak magnetic fields in the diffuse medium in general radiation fields.

  8. Single-photon superradiance and radiation trapping by atomic shells

    NASA Astrophysics Data System (ADS)

    Svidzinsky, Anatoly A.; Li, Fu; Li, Hongyuan; Zhang, Xiwen; Ooi, C. H. Raymond; Scully, Marlan O.

    2016-04-01

    The collective nature of light emission by atomic ensembles yields fascinating effects such as superradiance and radiation trapping even at the single-photon level. Light emission is influenced by virtual transitions and the collective Lamb shift which yields peculiar features in temporal evolution of the atomic system. We study how two-dimensional atomic structures collectively emit a single photon. Namely, we consider spherical, cylindrical, and spheroidal shells with two-level atoms continuously distributed on the shell surface and find exact analytical solutions for eigenstates of such systems and their collective decay rates and frequency shifts. We identify states which undergo superradiant decay and states which are trapped and investigate how size and shape of the shell affects collective light emission. Our findings could be useful for quantum information storage and the design of optical switches.

  9. DNA fragmentation induced by ionizing radiation - Atomic Force Microscopy study .

    NASA Astrophysics Data System (ADS)

    Gudowska-Nowak, E.; Psonka, K.; Elsaesser, Th.; Brons, S.; Taucher-Scholz, G.

    DNA as a carrier of genetic information is considered to be the critical target for radiation induced damage Especially severe are DNA double-strand breaks DSBs formed when breaks occur in both strands of the molecule The DSBs production is determined by the spatial distribution of ionization events dependent on the physical properties of the energy deposition and the chemical environment of the DNA According to theoretical predictions high LET charged particle radiation induces lesions in close proximity forming so called clustered damage in the DNA Atomic Force Microscopy AFM was newly established as a technique allowing the direct visualization of DNA fragments resulting from DSBs induced in small DNA molecules plasmids by ionizing radiation We have used AFM to visualize the DNA fragmentation induced by heavy ions high LET radiation and to compare it to the fragmentation pattern obtained after X-rays low LET radiation Plasmid supercoiled DNA was irradiated in vitro with X-rays and 3 9 MeV u Ni ions within a dose range 0 -- 3000 Gy Afterwards the samples were analyzed using AFM which allowed the detection and length measurement of individual fragments with a nanometer resolution Recording of the length of the induced fragments allowed to distinguish between molecules broken by a single DSB or by multiple DSBs The fragment length distributions were derived for different doses and different radiation qualities The first results of the measurement of radiation-induced DNA fragmentation show an influence of radiation quality on

  10. Evaluation of atomic constants for optical radiation, volume 1

    NASA Technical Reports Server (NTRS)

    Kylstra, C. D.; Schneider, R. J.

    1974-01-01

    Atomic constants for optical radiation are discussed which include transition probabilities, line strengths, and oscillator strengths for both dipole and quadrupole transitions, as well as the associated matrix elements needed for line broadening calculations. Atomic constants were computed for a wide selection of elements and lines. An existing computer program was used, with modifications to include, in an approximate manner, the effect of equivalent electrons, and to enable reordering and restructuring of the output for publication. This program is suitable for fast, low cost computation of the optical constants, using the Coulomb approximation formalism for LS coupling.

  11. Localisation of atomic populations in the optical radiation field

    SciTech Connect

    Efremova, E A; Gordeev, M Yu; Rozhdestvensky, Yu V

    2014-10-31

    The possibility of two-dimensional spatial localisation of atomic populations under the influence of the travelling wave fields in the tripod-configuration of quantum states is studied for the first time. Three travelling waves propagating in the same plane at an angle of 120° to each other form a system of standing waves under the influence of which atomic populations are localised. The size of the region of spatial localisation of the populations, in principle, can be hundredths of a wavelength of optical radiation. (quantum optics)

  12. Radiation force on a single atom in a cavity

    NASA Technical Reports Server (NTRS)

    Kim, M. S.

    1992-01-01

    We consider the radiation pressure microscopically. Two perfectly conducting plates are parallelly placed in a vacuum. As the vacuum field hits the plates they get pressure from the vacuum. The excessive outside modes of the vacuum field push the plates together, which is known as the Casimer force. We investigate the quantization of the standing wave between the plates to study the interaction between this wave and the atoms on the plates or between the plates. We show that even the vacuum field pushes the atom to place it at nodes of the standing wave.

  13. Boundary effects on radiative processes of two entangled atoms

    NASA Astrophysics Data System (ADS)

    Arias, E.; Dueñas, J. G.; Menezes, G.; Svaiter, N. F.

    2016-07-01

    We analyze radiative processes of a quantum system composed by two identical two-level atoms interacting with a massless scalar field prepared in the vacuum state in the presence of perfect reflecting flat mirrors. We consider that the atoms are prepared in a stationary maximally entangled state. We investigate the spontaneous transitions rates from the entangled states to the collective ground state induced by vacuum fluctuations. In the empty-space case, the spontaneous decay rates can be enhanced or inhibited depending on the specific entangled state and changes with the distance between the atoms. Next, we consider the presence of perfect mirrors and impose Dirichlet boundary conditions on such surfaces. In the presence of a single mirror the transition rate for the symmetric state undergoes a slight reduction, whereas for the antisymmetric state our results indicate a slightly enhancement. Finally, we investigate the effect of multiple reflections by two perfect mirrors on the transition rates.

  14. EFFECTS OF LASER RADIATION ON MATTER: Spectrum of the barium atom in a laser radiation field

    NASA Astrophysics Data System (ADS)

    Bondar', I. I.; Suran, V. V.

    1990-08-01

    An experimental investigation was made of the influence of a laser radiation field on the spectrum of barium atoms. The investigation was carried out by the method of three-photon ionization spectroscopy using dye laser radiation (ω = 14 800-18 700 cm - 1). The electric field intensity of the laser radiation was 103-106 V/cm. This laser radiation field had a strong influence on a number of bound and autoionizing states. The nature of this influence depended on the ratio of the excitation frequencies of bound and autoionizing states.

  15. Ionizing radiation and kidney cancer among Japanese atomic bomb survivors.

    PubMed

    Richardson, David B; Hamra, Ghassan

    2010-06-01

    Understanding of the role of radiation as a cause of kidney cancer remains limited. The most common types of kidney cancer are renal cell carcinoma and renal pelvis carcinoma. It has been posited that these entities differ in their degree of radiogenicity. Recent analyses of cancer incidence and mortality in the Life Span Study (LSS) of Japanese atomic bomb survivors have examined associations between ionizing radiation and renal cell carcinoma, but these analyses have not reported results for cancer of the renal pelvis and ureters. This paper reports the results of analyses of kidney cancer incidence during the period 1958-1998 among 105,427 atomic bomb survivors. Poisson regression methods were used to derive estimates of associations between radiation dose (in sievert, Sv) and cancer of the renal parenchyma (n = 167), and cancer of the renal pelvis and ureter (n = 80). Heterogeneity by cancer site was tested by joint modeling of cancer risks. Radiation dose was positively associated with cancers of the renal pelvis and ureter [excess relative rate (ERR)/Sv = 1.65; 90% confidence interval (CI): 0.37, 3.78]. The magnitude of this association was larger than the estimated association between radiation dose and cancer of the renal parenchyma (ERR/Sv = 0.27; 90% CI = -0.19, 0.98). While the association between radiation and cancer of the renal parenchyma was of greater magnitude at ages <55 years (ERR/Sv = 2.82; 90% CI = 0.45, 8.89) than at older attained ages (ERR/Sv = -0.11; 90% CI = nd, 0.53), the association between radiation and cancers of the renal pelvis and ureter varied minimally across these categories of attained age. A test of heterogeneity of type-specific risks provides modest support for the conclusion that risks vary by kidney cancer site (LRT = 2.34, 1 d.f., P = 0.13). Since some studies of radiation-exposed populations examine these sites in aggregate, results were also derived for the combined category of cancer of the renal parenchyma, renal

  16. Ionizing radiation and kidney cancer among Japanese atomic bomb survivors.

    PubMed

    Richardson, David B; Hamra, Ghassan

    2010-06-01

    Understanding of the role of radiation as a cause of kidney cancer remains limited. The most common types of kidney cancer are renal cell carcinoma and renal pelvis carcinoma. It has been posited that these entities differ in their degree of radiogenicity. Recent analyses of cancer incidence and mortality in the Life Span Study (LSS) of Japanese atomic bomb survivors have examined associations between ionizing radiation and renal cell carcinoma, but these analyses have not reported results for cancer of the renal pelvis and ureters. This paper reports the results of analyses of kidney cancer incidence during the period 1958-1998 among 105,427 atomic bomb survivors. Poisson regression methods were used to derive estimates of associations between radiation dose (in sievert, Sv) and cancer of the renal parenchyma (n = 167), and cancer of the renal pelvis and ureter (n = 80). Heterogeneity by cancer site was tested by joint modeling of cancer risks. Radiation dose was positively associated with cancers of the renal pelvis and ureter [excess relative rate (ERR)/Sv = 1.65; 90% confidence interval (CI): 0.37, 3.78]. The magnitude of this association was larger than the estimated association between radiation dose and cancer of the renal parenchyma (ERR/Sv = 0.27; 90% CI = -0.19, 0.98). While the association between radiation and cancer of the renal parenchyma was of greater magnitude at ages <55 years (ERR/Sv = 2.82; 90% CI = 0.45, 8.89) than at older attained ages (ERR/Sv = -0.11; 90% CI = nd, 0.53), the association between radiation and cancers of the renal pelvis and ureter varied minimally across these categories of attained age. A test of heterogeneity of type-specific risks provides modest support for the conclusion that risks vary by kidney cancer site (LRT = 2.34, 1 d.f., P = 0.13). Since some studies of radiation-exposed populations examine these sites in aggregate, results were also derived for the combined category of cancer of the renal parenchyma, renal

  17. Radiation-induced collisional pumping of molecules containing few atoms

    SciTech Connect

    Vasil'ev, G.K.; Chernyshev, Y.A.; Makarov, E.F.; Yakushev, V.G.

    1986-01-01

    The authors analyze the radiation-induced collisional pumping of few-atom molecules by laser emission taking into account both collisional and noncollisional processes of vibrational energy transfer in a molecule. For typical values of the parameters the vibrational energy of the molecules was found to depend on the laser emission intensity; regions of weak absorption, optimum absorption, and saturation appear as the pumping rate rises. Qualitative general conclusions are reached concerning the optimum conditions for the realization, in a medium absorbing laser emission, of either nonequilibrium dissociation or a chemical reaction involving vibrationally excited molecules.

  18. One minute after the detonation of the atomic bomb: the erased effects of residual radiation.

    PubMed

    Takahashi, Hiroko

    2009-01-01

    The U.S. Government's official narrative denies the effects of residual radiation which appeared one minute after the atomic bomb detonations in Hiroshima and Nagasaki. This paper explores declassified documents from the U.S. Atomic Energy Commission, the Atomic Bomb Casualties Commission, and others and shows that these documents actually suggested the existence of serious effects from residual radiation. PMID:20521423

  19. Infrared [Fe II] Emission Lines from Radiative Atomic Shocks

    NASA Astrophysics Data System (ADS)

    Koo, Bon-Chul; Raymond, John C.; Kim, Hyun-Jeong

    2016-06-01

    [Fe II] emission lines are prominent in the infrared (IR) and important as diagnostic tools for radiative atomic shocks. We investigate the emission characteristics of [Fe II] lines using a shock code developed by te{raymond1979} with updated atomic parameters. We first review general characteristics of the IR [Fe II] emission lines from shocked gas, and derive their fluxes as a function of shock speed and ambient density. We have compiled available IR [Fe II] line observations of interstellar shocks and compare them to the ratios predicted from our model. The sample includes both young and old supernova remnants in the Galaxy and the Large Magellanic Cloud and several Herbig-Haro objects. We find that the observed ratios of the IR [Fe II] lines generally fall on our grid of shock models, but the ratios of some mid-IR lines, e.g., fethreefive/fetwofive, fefive/fetwofive, and fefive/feoneseven, are significantly offset from our model grid. We discuss possible explanations and conclude that while uncertainties in the shock modeling and the observations certainly exist, the uncertainty in atomic rates appears to be the major source of discrepancy.

  20. The Effect of Intense Laser Radiation on Atomic Collisions

    NASA Astrophysics Data System (ADS)

    Young, Stephen Michael Radley

    1991-02-01

    Available from UMI in association with The British Library. Requires signed TDF. We have carried out theoretical and experimental studies into the effect of intense laser radiation on atomic collisions. The first experiment used neon. Excitation by electron impact in a gas discharge demanded a pressure of at least 0.075 Torr. Measurement of the intensity of 3^1S_0to 3^1P_1 fluorescence has been made for the case where high intensity ASE wings in the laser profile and background laser scatter are unimportant, with the laser tuned to resonance. The field intensity required to produce strong field fluorescence (exemplified by the Mollow triplet) was found to give rise to complications capable of screening the effects sought. Our theoretical model has suggested that at finite detunings, line-centre fluorescence will dominate Rayleigh scatter and omega_3 fluorescence. Our measurements provide information on the saturation of neon fluorescence but not of the variation of the intense field collision rate. Absorption of weak field 253.7 nm laser photons by ground state mercury atoms yielded a high 6 ^3P_1 population at a lower pressure of 0.02 Torr. The Mollow triplet has been observed in the self-broadened mercury system. Dressing of the upper transition (6^3P_1rightarrow 7^3S_1) by an intense laser close to 435.8 nm yielded the strong field signal. Polarisation studies were made possible by the 3-level mercury system (radiation trapping in a 2-level system would depolarise fluorescence) perturbed by argon. The studies yielded results that were explainable in terms of the selective population of Stark shifted dressed states by a detuned, weak probe field. Use has been made of the electric-dipole radiation selection rule m_{J}=0 rightarrow m_{J^' } = 0 unless J=J^' to devise a 'Stark shift collision switch'. The competition between collision and radiation induced transitions within the mercury atom has then been studied. The resonant, strong lambda 435.8 nm field was used

  1. The international atom: evolution of radiation control programs.

    PubMed

    Bradley, F J

    2002-07-01

    Under the Atoms for Peace program, Turkey received a one MWt swimming pool reactor in 1962 that initiated a health physics program for the reactor and a Radiation Control Program (RCP) for the country's use of ionizing radiation. Today, over 13,000 radiation workers, concentrated in the medical field, provide improved medical care with 6,200 x-ray units, including 494 CAT scanners, 222 radioimmunoassay (RIA) labs and 42 radiotherapy centers. Industry has a large stake in the safe use of ionizing radiation with over 1,200 x-ray and gamma radiography and fluoroscopic units, 2,500 gauges in automated process control and five irradiators. A 48-person RCP staff oversees this expanded radiation use. One incident involving a spent 3.3 TBq (88 Ci) 60Co source resulted in 10 overexposures but no fatalities. Taiwan received a 1.6 MWt swimming pool reactor in 1961 and rapidly applied nuclear technology to the medical and industrial fields. Today, there are approximately 24,000 licensed radiation workers in nuclear power field, industry, medicine and academia. Four BWRs and two PWRs supply about 25% of the island's electrical power needs. One traumatic event galvanized the RCP when an undetermined amount of 60Co was accidentally incorporated into reinforcing bars, which in turn were incorporated into residential and commercial buildings. Public exposures were estimated to range up to 15 mSv (1.3 rem) per annum. There were no reported ill effects, except possibly psychological, to date. The RCP now has instituted stringent control measures to ensure radiation-free dwellings and work places. Albania's RCP is described as it evolved since 1972. Regulations were promulgated which followed the IAEA Basic Safety Standards of that era. With 525 licenses and 600 radiation workers, the problem was not in the regulations per se but in their enforcement. The IAEA helped to upgrade the RCP as the economy evolved from one that was centrally planned economy to a free market economy. As this

  2. Risk estimates for radiation-induced cancer and radiation protection standards

    SciTech Connect

    Sinclair, W.K. )

    1989-11-01

    At low doses, the primary biological effects of concern are stochastic in nature, i.e., they are more probable at higher doses, but their severity is independent of the dose. In the last decade, a new epidemiological information on radiation-induced cancer in humans has become available. In the Japanese survivors three new cycles of data (11 yr of experience) have accumulated, and a revised dosimetry system (DS86) has been introduced. UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) reevaluated the risk of cancer from all human sources, which include other human populations such as those treated for ankylosing spondylitis and for cancer of the cervix. UNSCEAR has also evaluated the cancer risk for each of nine organs. For radiation protection purposes (low doses and dose rates, adult populations mainly), nominal values of risk since the 1977-80 period have been {approximately}1%/Sv. This value will need to be increased in the light of the new estimates. Also, risk estimates for various tissues must be reconsidered, and weighting factors used by International Commission on Radiological Protection need to be reexamined. Recommendations on occupational and public dose limits must also be reconsidered. The National Council on Radiation Protection and Measurements is in a comparatively good position with a recently produced set of recommendations that had higher cancer risk estimates in mind.

  3. Dynamical overstability of radiative blast waves: the atomic physics of shock stability.

    PubMed

    Laming, J Martin; Grun, Jacob

    2002-09-16

    Atomic-physics calculations of radiative cooling are used to develop criteria for the overstability of radiating shocks. Our calculations explain the measurement of shock overstability by Grun et al. [Phys. Rev. Lett. 66, 2738 (1991)

  4. Test of atomic theory by photoelectron spectrometry with synchrotron radiation

    SciTech Connect

    Krause, M.O.

    1984-01-01

    The successful combination of synchrotron radiation with electron spectrometry, accomplished at Daresbury, England and Orsay, France, made it possible to investigate sigma/sub x/ and ..beta../sub x/ continuously over the very soft x-ray or the uv range of photon energies. The detailed and highly differentiated data resulting from this advanced experimentation put theory to a stringent test. In the interplay between theory and experiment, sophisticated Hartree Fock (HF) based models were developed which included both relativistic and many-electron effects. These theoretical models have provided us with a better insight than previously possible into the physics of the photon-atom interaction and the electronic structure and dynamics of atoms. However, critical experiments continue to be important for further improvements of theory. A number of such experiments are discussed in this presentation. The dynamic properties determined in these studies include in addition to sigma/sub x/ and ..beta../sub x/ the spin polarization parameters. As a result the comparison between theory and experiment becomes rigorous, detailed and comprehensive. 46 references, 6 figures.

  5. Monitoring exposure to atomic bomb radiation by somatic mutation

    SciTech Connect

    Akiyama, Mitoshi; Kyoizumi, Seishi; Kusunoki, Yoichiro

    1996-05-01

    Atomic bomb survivors are a population suitable for studying the relationship between somatic mutation and cancer risk because their exposure doses are relatively well known and their dose responses in terms of cancer risk have also been thoroughly studied. An analysis has been made of erythrocyte glycophorin A (GPA) gene mutations in 1,226 atomic bomb survivors in Hiroshima and Nagasaki. The GPA mutation frequency (Mf) increased slightly but significantly with age at the time of measurement and with the number of cigarettes smoked. After adjustment for the effect of smoking, the Mf was significantly higher in males than in females and higher in Hiroshima than in Nagasaki. All of these characteristics of the background GPA Mf were in accord with those of solid tumor incidence obtained from an earlier epidemiological study of A-bomb survivors. Analysis of the dose effect on Mf revealed the doubling dose to be about 1.20 Sv and the minimum dose for detection of a significant increase to be about 0.24 Sv. No significant dose effect for difference in sex, city, or age at the time of bombing was observed. Interestingly, the doubling dose for the GPA Mf approximated that for solid cancer incidence (1.59 Sv). And the minimum dose for detection was not inconsistent with the data for solid cancer incidence. The dose effect was significantly higher in those diagnosed with cancer before or after measurement than in those without a history of cancer. These findings are consistent with the hypothesis that somatic mutations are the main cause of excess cancer risk from radiation exposure. 27 refs., 2 figs.

  6. On- and off-resonance radiation-atom-coupling matrix elements involving extended atomic wave functions

    NASA Astrophysics Data System (ADS)

    Komninos, Yannis; Mercouris, Theodoros; Nicolaides, Cleanthes A.

    2014-01-01

    In continuation of our earlier works, we present results concerning the computation of matrix elements of the multipolar Hamiltonian (MPH) between extended wave functions that are obtained numerically. The choice of the MPH is discussed in connection with the broader issue of the form of radiation-atom (or -molecule) interaction that is appropriate for the systematic solution of various problems of matter-radiation interaction. We derive analytic formulas, in terms of the sine-integral function and spherical Bessel functions of various orders, for the cumulative radial integrals that were obtained and calculated by Komninos, Mercouris, and Nicolaides [Phys. Rev. A 71, 023410 (2005), 10.1103/PhysRevA.71.023410]. This development allows the much faster and more accurate computation of such matrix elements, a fact that enhances the efficiency with which the time-dependent Schrödinger equation is solved nonperturbatively, in the framework of the state-specific expansion approach. The formulas are applicable to the general case where a pair of orbitals with angular parts |ℓ1,m1> and |ℓ2,m2> are coupled radiatively. As a test case, we calculate the matrix elements of the electric field and of the paramagnetic operators for on- and off-resonance transitions, between hydrogenic circular states of high angular momentum, whose quantum numbers are chosen so as to satisfy electric dipole and electric quadrupole selection rules. Because of the nature of their wave function (they are nodeless and the large centrifugal barrier keeps their overwhelming part at large distances from the nucleus), the validity of the electric dipole approximation in various applications where the off-resonance couplings must be considered becomes precarious. For example, for the transition from the circular state with n = 20 to that with n = 21, for which ≈400 a.u., the dipole approximation starts to fail already at XUV wavelengths (λ <125nm).

  7. Experiments in atomic and applied physics using synchrotron radiation

    SciTech Connect

    Jones, K.W.

    1987-01-01

    A diverse program in atomic and applied physics using x rays produced at the X-26 beam line at the Brookhaven National Synchrotron Light Source is in progress. The atomic physics program studies the properties of multiply-ionized atoms using the x rays for photo-excitation and ionization of neutral atoms and ion beams. The applied physics program builds on the techniques and results of the atomic physics work to develop new analytical techniques for elemental and chemical characterization of materials. The results are then used for a general experimental program in biomedical sciences, geo- and cosmochemistry, and materials sciences. The present status of the program is illustrated by describing selected experiments. Prospects for development of new experimental capabilities are discussed in terms of a heavy ion storage ring for atomic physics experiments and the feasibility of photoelectron microscopy for high spatial resolution analytical work. 21 refs., 11 figs., 2 tabs.

  8. The Natural Radiation Environment, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Kastner, Jacob

    The somatic and genetic effects of naturally occurring radiation are described in this illustrated booklet. Internal sources of radiation from food, water, and air and external sources including radioisotopes in rock, brick, water, and air and cosmic radiation are tabulated. Detection methods are described, and their use in biological and physical…

  9. Applications of atomic and molecular data to radiation physics

    SciTech Connect

    Inokuti, M.

    1982-01-01

    The general purpose of our work is to provide atomic and molecular collision cross sections useful for radiological physics, dosimetry, and other applications. Studies on the systematics of atomic oscillator-strength spectra and a survey of stopping power data are briefly described. (WHK)

  10. Radiative and Non-Radiative Lifetime Engineering of Quantum Dots in Multiple Solvents by Surface Atom Stoichiometry and Ligands

    PubMed Central

    Omogo, Benard; Aldana, Jose F.; Heyes, Colin D.

    2013-01-01

    CdTe quantum dots have unique characteristics that are promising for applications in photoluminescence, photovoltaics or optoelectronics. However, wide variations of the reported quantum yields exist and the influence of ligand-surface interactions that are expected to control the excited state relaxation processes remains unknown. It is important to thoroughly understand the fundamental principles underlying these relaxation processes to tailor the QDs properties to their application. Here, we systematically investigate the roles of the surface atoms, ligand functional groups and solvent on the radiative and non-radiative relaxation rates. Combining a systematic synthetic approach with X-ray photoelectron, quantitative FT-IR and time-resolved visible spectroscopies, we find that CdTe QDs can be engineered with average radiative lifetimes ranging from nanoseconds up to microseconds. The non-radiative lifetimes are anticorrelated to the radiative lifetimes, although they show much less variation. The density, nature and orientation of the ligand functional groups and the dielectric constant of the solvent play major roles in determining charge carrier trapping and excitonic relaxation pathways. These results are used to propose a coupled dependence between hole-trapping on Te atoms and strong ligand coupling, primarily via Cd atoms, that can be used to engineer both the radiative and non-radiative lifetimes. PMID:23543893

  11. Optical radiation and ionization of hydrogen atoms in heterogeneous exothermal reactions proceeding in an electric field

    NASA Astrophysics Data System (ADS)

    Blashenkov, N. M.; Lavrent'ev, G. Ya.

    2009-09-01

    Optical radiation related to the Balmer series (Hα, Hβ, Hγ) of hydrogen atoms is discovered when studying the isothermal reaction of trimeric acetone peroxide decomposition on the surface of oxidized tungsten in a static electric field with a strength of up to 4 × 106 V/cm at T = 300 K. The distance from the surface over which desorbing excited hydrogen atoms radiate is determined from the Stark splitting of the lines. Electronically excited atoms remaining on the surface ionize according to the surface ionization mechanism.

  12. A case of malignant pleural mesothelioma following exposure to atomic radiation in Nagasaki.

    PubMed

    Mizuki, M; Yukishige, K; Abe, Y; Tsuda, T

    1997-09-01

    We report the case of a 75-year-old Japanese man who developed malignant mesothelioma in the left hemithorax 50 years after the dropping of the atomic bomb on Nagasaki in 1945. This may be the first reported case of malignant mesothelioma following exposure to atomic radiation. Asbestos is the leading cause of malignant mesothelioma, but radiation therapy is the primary non-asbestos-related cause. In the case of radiation therapy, the interval between exposure and the occurrence of malignant mesothelioma tends to be many years. This patient was at a high risk of malignant mesothelioma as he had been exposed to radiation from the atomic bomb and may also have had a history of asbestos exposure at the munitions factory where he was employed as a shipbuilder for 2 years. It has been suggested that combined exposure to atomic radiation and asbestos is associated with an increased incidence of malignant mesothelioma. If thickening of the pleura or pleural effusion is found in atomic bomb survivors, malignant mesothelioma should be considered as one of the options in the differential diagnosis, even although the atomic bomb attacks occurred several decades ago.

  13. Mapping of laser diode radiation intensity by atomic-force microscopy

    NASA Astrophysics Data System (ADS)

    Alekseev, P. A.; Dunaevskii, M. S.; Slipchenko, S. O.; Podoskin, A. A.; Tarasov, I. S.

    2015-09-01

    The distribution of the intensity of laser diode radiation has been studied using an original method based on atomic-force microscopy (AFM). It is shown that the laser radiation intensity in both the near field and transition zone of a high-power semiconductor laser under room-temperature conditions can be mapped by AFM at a subwavelength resolution. The obtained patterns of radiation intensity distribution agree with the data of modeling and the results of near-field optical microscopy measurements.

  14. Atomic oxygen and ultraviolet radiation mission total exposures for LDEF experiments

    NASA Technical Reports Server (NTRS)

    Bourassa, R. J.; Gillis, J. R.; Rousslang, Ken W.

    1992-01-01

    Atomic oxygen and solar radiation exposures were determined analytically for rows, longerons, and end bays of the LDEF. Calculated atomic oxygen exposures are based on an analytical model that accounts for the effects of thermal molecular velocity, atmospheric temperature, number density, spacecraft velocity, incidence angle, and atmospheric rotation. Results also incorporate variations in solar activity, geomagnetic index, and orbital parameters occurring over the six year flight of the spacecraft. Solar radiation exposure calculations are based on the form factors reported in the Solar Illumination Data Package prepared by NASA Langley. The earth albedo value for these calculations was based on the Nimbus 7 earth radiation data set. Summary charts for both atomic oxygen and solar radiation exposure are presented to facilitate the use of the data generated by LDEF experimenters.

  15. Fullerene-Encapsulated Atoms in the Light of Synchrotron Radiation

    SciTech Connect

    Mueller, A.; Schippers, S.; Esteves, D.; Habibi, M.; Phaneuf, R. A.; Kilcoyne, A. L. D.; Aguilar, A.; Dunsch, L.

    2009-12-03

    Mass-selected beams of endohedral fullerene Ce-C{sub 82}{sup +} ions, of atomic Ce{sup q+} ions (q = 2, 3, 4), and of empty fullerene-cage C{sub 82}{sup +} ions were employed to study photoionization of fullerene-encapsulated and free cerium atoms. The Ce 4d inner-shell contributions to single and double ionization of the endohedral Ce-C{sub 82}{sup +} fullerene have been extracted from the data and compared with expectations based on theory and the experiments with atomic Ce ions. Dramatic reduction and redistribution of the ionization contributions to Ce 4d photoabsorption is observed. More than half of the Ce 4d oscillator strength is apparently diverted to additional decay channels of the Ce-C{sub 82}{sup +} complex.

  16. Epidemiological research on radiation-induced cancer in atomic bomb survivors.

    PubMed

    Ozasa, Kotaro

    2016-08-01

    The late effects of exposure to atomic bomb radiation on cancer occurrence have been evaluated by epidemiological studies on three cohorts: a cohort of atomic bomb survivors (Life Span Study; LSS), survivors exposed IN UTERO : , and children of atomic bomb survivors (F1). The risk of leukemia among the survivors increased remarkably in the early period after the bombings, especially among children. Increased risks of solid cancers have been evident since around 10 years after the bombings and are still present today. The LSS has clarified the dose-response relationships of radiation exposure and risk of various cancers, taking into account important risk modifiers such as sex, age at exposure, and attained age. Confounding by conventional risk factors including lifestyle differences is not considered substantial because people were non-selectively exposed to the atomic bomb radiation. Uncertainty in risk estimates at low-dose levels is thought to be derived from various sources, including different estimates of risk at background levels, uncertainty in dose estimates, residual confounding and interaction, strong risk factors, and exposure to residual radiation and/or medical radiation. The risk of cancer in subjects exposed IN UTERO : is similar to that in LSS subjects who were exposed in childhood. Regarding hereditary effects of radiation exposure, no increased risk of cancers associated with parental exposure to radiation have been observed in the F1 cohort to date. In addition to biological and pathogenetic interpretations of the present results, epidemiological investigations using advanced technology should be used to further analyze these cohorts.

  17. The role of atomic lines in radiation heating of the experimental space vehicle Fire-II

    NASA Astrophysics Data System (ADS)

    Surzhikov, S. T.

    2015-10-01

    The results of calculating the convective and radiation heating of the Fire-II experimental space vehicle allowing for atomic lines of atoms and ions using the NERAT-ASTEROID computer platform are presented. This computer platform is intended to solve the complete set of equations of radiation gas dynamics of viscous, heat-conductive, and physically and chemically nonequilibrium gas, as well as radiation transfer. The spectral optical properties of high temperature gases are calculated using ab initio quasi-classical and quantum-mechanical methods. The calculation of the transfer of selective thermal radiation is performed using a line-by-line method using specially generated computational grids over the radiation wavelengths, which make it possible to attain a noticeable economy of computational resources.

  18. [Cohort studies of the atomic bomb survivors at the Radiation Effects Research Foundation].

    PubMed

    Ozasa, Kotaro

    2012-03-01

    The Radiation Effects Research Foundation has been evaluating the risk of atomic bomb radiation for various diseases since the beginning of its former organization, the Atomic Bomb Casualty Commission. Cohorts of atomic-bomb survivors, in-utero survivors, and survivors' offspring have been followed up. The risk of all solid cancers at 1 Gy was estimated as ERR = 0.47 and EAR = 52/10,000 person-years for people who were exposed at 30 years of age and had reached 70 years of age, based on the cancer incidence during 1958-1998. The risk seemed to be increased in the in-utero survivors, but was rather lower than the risk for the survivors exposed at a young age. Effects on the offspring of survivors have not been shown to be significant. Continuing the research is important in order to more accurately estimate and understand radiation-induced health effects.

  19. [Cohort studies of the atomic bomb survivors at the Radiation Effects Research Foundation].

    PubMed

    Ozasa, Kotaro

    2012-03-01

    The Radiation Effects Research Foundation has been evaluating the risk of atomic bomb radiation for various diseases since the beginning of its former organization, the Atomic Bomb Casualty Commission. Cohorts of atomic-bomb survivors, in-utero survivors, and survivors' offspring have been followed up. The risk of all solid cancers at 1 Gy was estimated as ERR = 0.47 and EAR = 52/10,000 person-years for people who were exposed at 30 years of age and had reached 70 years of age, based on the cancer incidence during 1958-1998. The risk seemed to be increased in the in-utero survivors, but was rather lower than the risk for the survivors exposed at a young age. Effects on the offspring of survivors have not been shown to be significant. Continuing the research is important in order to more accurately estimate and understand radiation-induced health effects. PMID:22514915

  20. Exotic hollow atom states pumped by relativistic laser plasma in a radiation dominant regime

    NASA Astrophysics Data System (ADS)

    Woolsey, Nigel; Pikuz, S. A.; Faenov, A. Ya; Dance, R. J.; Wagenaars, E.; Booth, N.; Culfa, O.; Evans, R. G.; Gray, R. J.; Kaempfer, T.; Lancaster, K. L.; McKenna, P.; Rossall, A. L.; Skobelev, I. Yu; Schulze, K. S.; Uschmann, I.; Zhidkov, A. G.; Abdallah, J., Jr.; Colgan, J.

    2013-10-01

    In high-spectral resolution experiments with the petawatt Vulcan laser, strong x-ray radiation of KK hollow atoms (atoms without n = 1 electrons) from aluminium targets was observed at high laser contrast, for intensities of 3 × 1020 Wcm-2 and micron thick targets. These spectral observations are interpreted using detailed atomic kinetics calculations suggesting these exotic hollow atom states occur at near solid density and are driven by an intense polychromatic x-ray field. We estimate that this x-ray radiation field has energy in the kilovolt range and has an intensity exceeding 1018 Wcm-2. The field may arise through relativistic electron Thomson scattering and bremsstrahlung in the electrostatic fields at the target surface.

  1. Greetings: 50 years of Atomic Bomb Casualty Commission-Radiation Effects Research Foundation studies.

    PubMed

    Shigematsu, I

    1998-05-12

    The Atomic Bomb Casualty Commission was established in Hiroshima in 1947 and in Nagasaki in 1948 under the auspices of the U.S. National Academy of Sciences to initiate a long-term and comprehensive epidemiological and genetic study of the atomic bomb survivors. It was replaced in 1975 by the Radiation Effects Research Foundation which is a nonprofit Japanese foundation binationally managed and supported with equal funding by the governments of Japan and the United States. Thanks to the cooperation of the survivors and the contributions of a multitude of scientists, these studies flourish to this day in what must be the most successful long-term research collaboration between the two countries. Although these studies are necessarily limited to the effects of acute, whole-body, mixed gamma-neutron radiation from the atom bombs, their comprehensiveness and duration make them the most definitive descriptions of the late effects of radiation in humans. For this reason, the entire world relies heavily on these data to set radiation standards. As vital as the study results are, they still represent primarily the effects of radiation on older survivors. Another decade or two should correct this deficiency and allow us to measure definitively the human risk of heritable mutation from radiation. We look to the worldwide radiation and risk community as well as to the survivors who have contributed so much to what has been done already to accomplish this goal.

  2. Manipulating ion-atom collisions with coherent electromagnetic radiation.

    PubMed

    Kirchner, Tom

    2002-08-26

    Laser-assisted ion-atom collisions are considered in terms of a nonperturbative quantum mechanical description of the electronic motion. It is shown for the system He(2+) - H at 2 keV/amu that the collision dynamics depend strongly on the initial phase of the laser field and the applied wavelength. Whereas electronic transitions are caused by the concurrent action of the field and the projectile ion at relatively low frequencies, they can be separated into modified collisional capture and field ionization events in the region above the one-photon ionization threshold.

  3. Synergistic effects of ultraviolet radiation, thermal cycling and atomic oxygen on altered and coated Kapton surfaces

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Bruckner, Eric J.; Rodriguez, Elvin

    1992-01-01

    The photovoltaic (PV) power system for Space Station Freedom (SSF) uses solar array blankets which provide structural support for the solar cells and house the electrical interconnections. In the low earth orbital (LEO) environment where SSF will be located, surfaces will be exposed to potentially damaging environmental conditions including solar ultraviolet (UV) radiation, thermal cycling, and atomic oxygen. It is necessary to use ground based tests to determine how these environmental conditions would affect the mass loss and optical properties of candidate SSF blanket materials. Silicone containing, silicone coated, and SiO(x) coated polyimide film materials were exposed to simulated LEO environmental conditions to determine their durability and whether the environmental conditions of UV, thermal cycling and oxygen atoms act synergistically on these materials. A candidate PV blanket material called AOR Kapton, a polysiloxane polyimide cast from a solution mixture, shows an improvement in durability to oxygen atoms erosion after exposure to UV radiation or thermal cycling combined with UV radiation. This may indicate that the environmental conditions react synergistically with this material, and the damage predicted by exposure to atomic oxygen alone is more severe than that which would occur in LEO where atomic oxygen, thermal cycling and UV radiation are present together.

  4. Synergistic effects of ultraviolet radiation, thermal cycling, and atomic oxygen on altered and coated Kapton surfaces

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Bruckner, Eric J.; Rodriguez, Elvin

    1992-01-01

    The photovoltaic (PV) power system for Space Station Freedom (SSF) uses solar array blankets which provide structural support for the solar cells and house the electrical interconnections. In the low Earth orbital (LEO) environment where SSF will be located, surfaces will be exposed to potentially damaging environmental conditions including solar ultraviolet (UV) radiation, thermal cycling, and atomic oxygen. It is necessary to use ground based tests to determine how these environmental conditions would affect the mass loss and optical properties of candidate SSF blanket materials. Silicone containing, silicone coated, and SiO(x) coated polyimide film materials were exposed to simulated LEO environmental conditions to determine there durability and whether the environmental conditions of UV, thermal cycling and oxygen atoms act synergistically on these materials. A candidate PV blanket material called AOR Kapton, a polysiloxane polyimide cast from a solution mixture, shows an improvement in durability to oxygen atoms erosion after exposure to UV radiation or thermal cycling combined with UV radiation. This may indicate that the environmental conditions react synergistically with this material, and the damage predicted by exposure to atomic oxygen alone is more severe than that which would occur in LEO where atomic oxygen, thermal cycling and UV radiation are present together.

  5. To acquire more detailed radiation drive by use of ``quasi-steady'' approximation in atomic kinetics

    NASA Astrophysics Data System (ADS)

    Ren, Guoli; Pei, Wenbing; Lan, Ke; Gu, Peijun; Li, Xin

    2012-10-01

    In current routine 2D simulation of hohlraum physics, we adopt the principal-quantum- number(n-level) average atom model(AAM) in NLTE plasma description. However, the detailed experimental frequency-dependant radiative drive differs from our n-level simulated drive, which reminds us the need of a more detailed atomic kinetics description. The orbital-quantum- number(nl-level) average atom model is a natural consideration, however the nl-level in-line calculation needs much more computational resource. By distinguishing the rapid bound-bound atomic processes from the relative slow bound-free atomic processes, we found a method to build up a more detailed bound electron distribution(nl-level even nlm-level) using in-line n-level calculated plasma conditions(temperature, density, and average ionization degree). We name this method ``quasi-steady approximation'' in atomic kinetics. Using this method, we re-build the nl-level bound electron distribution (Pnl), and acquire a new hohlraum radiative drive by post-processing. Comparison with the n-level post-processed hohlraum drive shows that we get an almost identical radiation flux but with more fine frequency-denpending spectrum structure which appears only in nl-level transition with same n number(n=0) .

  6. Late effect of atomic bomb radiation on myeloid disorders: leukemia and myelodysplastic syndromes.

    PubMed

    Tsushima, Hideki; Iwanaga, Masako; Miyazaki, Yasushi

    2012-03-01

    Leukemia was the first malignancy linked to radiation exposure in atomic bomb survivors. Clear evidence of the dose-dependent excess risk of three major types of leukemia (acute lymphocytic leukemia, acute myeloid leukemia [AML], and chronic myeloid leukemia) was found, especially in people exposed at young ages. Such leukemia risks were at their highest in the late 1950s, and declined gradually thereafter over the past 50 years. Findings from recent risk analyses, however, suggest the persistence of AML risk even after 1990, and evidence of increased risk of myelodysplastic syndromes (MDS) due to atomic bomb radiation has recently been shown. High-risk MDS and forms involving complex chromosomal aberrations were found to be much more frequent in people exposed to higher radiation doses. These lines of epidemiological evidence suggest that the risk of radiation-induced hematological malignancies has persisted for six decades since the initial exposure.

  7. Late effect of atomic bomb radiation on myeloid disorders: leukemia and myelodysplastic syndromes.

    PubMed

    Tsushima, Hideki; Iwanaga, Masako; Miyazaki, Yasushi

    2012-03-01

    Leukemia was the first malignancy linked to radiation exposure in atomic bomb survivors. Clear evidence of the dose-dependent excess risk of three major types of leukemia (acute lymphocytic leukemia, acute myeloid leukemia [AML], and chronic myeloid leukemia) was found, especially in people exposed at young ages. Such leukemia risks were at their highest in the late 1950s, and declined gradually thereafter over the past 50 years. Findings from recent risk analyses, however, suggest the persistence of AML risk even after 1990, and evidence of increased risk of myelodysplastic syndromes (MDS) due to atomic bomb radiation has recently been shown. High-risk MDS and forms involving complex chromosomal aberrations were found to be much more frequent in people exposed to higher radiation doses. These lines of epidemiological evidence suggest that the risk of radiation-induced hematological malignancies has persisted for six decades since the initial exposure. PMID:22370711

  8. Sensitive measurement of radiation trapping in cold-atom clouds by intensity correlation detection.

    PubMed

    Stites, Ronald; Beeler, Matthew; Feeney, Laura; Kim, Soo; Bali, Samir

    2004-12-01

    We present experimental evidence that the intensity correlations of light scattered from a cold-atom cloud are sensitive to the presence of small amounts of radiation trapping in an atomic sample of density 6 x 10(8)/cm3, with an optical depth (for a resonant light beam) of 0.4. This density and optical depth are approximately an order of magnitude less than the density and on-resonance optical depth at which effects of multiple scattering in cold-atom clouds have been previously observed [Phys. Rev. Lett. 64, 408 (1990)].

  9. Effects of radiation on the incidence of prostate cancer among Nagasaki atomic bomb survivors.

    PubMed

    Kondo, Hisayoshi; Soda, Midori; Mine, Mariko; Yokota, Kenichi

    2013-10-01

    Atomic bomb survivors have been reported to have an increased risk of some cancers, especially leukemia. However, the risk of prostate cancer in atomic bomb survivors is not known to have been examined previously. This study examined the association between atomic bomb radiation and the incidence of prostate cancer among male Nagasaki atomic bomb survivors. The subjects were classified by distance from the hypocenter into a proximal group (<2 km), a distal group (≥2 km), and an early entrance group (those who entered the region <2 km from the hypocenter within 2 weeks after the explosion). Between 1996 and 2009, 631 new cases of prostate cancer were identified among approximately 18 400 male Nagasaki atomic bomb survivors who were alive in 1996. The Cox proportional hazard model was used to estimate the risk of prostate cancer development, with adjustment for age at atomic bomb explosion, attained age, smoking status, and alcohol consumption. Compared with the distal group, the proximal group had significant increased risks of total, localized, and high-grade prostate cancer (relative risk and 95% confidence interval: 1.51 [1.21-1.89]; 1.80 [1.26-2.57]; and 1.88 [1.20-2.94], respectively). This report is the first known to reveal a significant relationship between atomic bomb radiation and prostate cancer.

  10. Effects of radiation on the incidence of prostate cancer among Nagasaki atomic bomb survivors.

    PubMed

    Kondo, Hisayoshi; Soda, Midori; Mine, Mariko; Yokota, Kenichi

    2013-10-01

    Atomic bomb survivors have been reported to have an increased risk of some cancers, especially leukemia. However, the risk of prostate cancer in atomic bomb survivors is not known to have been examined previously. This study examined the association between atomic bomb radiation and the incidence of prostate cancer among male Nagasaki atomic bomb survivors. The subjects were classified by distance from the hypocenter into a proximal group (<2 km), a distal group (≥2 km), and an early entrance group (those who entered the region <2 km from the hypocenter within 2 weeks after the explosion). Between 1996 and 2009, 631 new cases of prostate cancer were identified among approximately 18 400 male Nagasaki atomic bomb survivors who were alive in 1996. The Cox proportional hazard model was used to estimate the risk of prostate cancer development, with adjustment for age at atomic bomb explosion, attained age, smoking status, and alcohol consumption. Compared with the distal group, the proximal group had significant increased risks of total, localized, and high-grade prostate cancer (relative risk and 95% confidence interval: 1.51 [1.21-1.89]; 1.80 [1.26-2.57]; and 1.88 [1.20-2.94], respectively). This report is the first known to reveal a significant relationship between atomic bomb radiation and prostate cancer. PMID:23859763

  11. Epidemiological research on radiation-induced cancer in atomic bomb survivors

    PubMed Central

    Ozasa, Kotaro

    2016-01-01

    The late effects of exposure to atomic bomb radiation on cancer occurrence have been evaluated by epidemiological studies on three cohorts: a cohort of atomic bomb survivors (Life Span Study; LSS), survivors exposed in utero, and children of atomic bomb survivors (F1). The risk of leukemia among the survivors increased remarkably in the early period after the bombings, especially among children. Increased risks of solid cancers have been evident since around 10 years after the bombings and are still present today. The LSS has clarified the dose–response relationships of radiation exposure and risk of various cancers, taking into account important risk modifiers such as sex, age at exposure, and attained age. Confounding by conventional risk factors including lifestyle differences is not considered substantial because people were non-selectively exposed to the atomic bomb radiation. Uncertainty in risk estimates at low-dose levels is thought to be derived from various sources, including different estimates of risk at background levels, uncertainty in dose estimates, residual confounding and interaction, strong risk factors, and exposure to residual radiation and/or medical radiation. The risk of cancer in subjects exposed in utero is similar to that in LSS subjects who were exposed in childhood. Regarding hereditary effects of radiation exposure, no increased risk of cancers associated with parental exposure to radiation have been observed in the F1 cohort to date. In addition to biological and pathogenetic interpretations of the present results, epidemiological investigations using advanced technology should be used to further analyze these cohorts. PMID:26976124

  12. Epidemiological research on radiation-induced cancer in atomic bomb survivors.

    PubMed

    Ozasa, Kotaro

    2016-08-01

    The late effects of exposure to atomic bomb radiation on cancer occurrence have been evaluated by epidemiological studies on three cohorts: a cohort of atomic bomb survivors (Life Span Study; LSS), survivors exposed IN UTERO : , and children of atomic bomb survivors (F1). The risk of leukemia among the survivors increased remarkably in the early period after the bombings, especially among children. Increased risks of solid cancers have been evident since around 10 years after the bombings and are still present today. The LSS has clarified the dose-response relationships of radiation exposure and risk of various cancers, taking into account important risk modifiers such as sex, age at exposure, and attained age. Confounding by conventional risk factors including lifestyle differences is not considered substantial because people were non-selectively exposed to the atomic bomb radiation. Uncertainty in risk estimates at low-dose levels is thought to be derived from various sources, including different estimates of risk at background levels, uncertainty in dose estimates, residual confounding and interaction, strong risk factors, and exposure to residual radiation and/or medical radiation. The risk of cancer in subjects exposed IN UTERO : is similar to that in LSS subjects who were exposed in childhood. Regarding hereditary effects of radiation exposure, no increased risk of cancers associated with parental exposure to radiation have been observed in the F1 cohort to date. In addition to biological and pathogenetic interpretations of the present results, epidemiological investigations using advanced technology should be used to further analyze these cohorts. PMID:26976124

  13. Incidence of dementia among atomic-bomb survivors--Radiation Effects Research Foundation Adult Health Study.

    PubMed

    Yamada, Michiko; Kasagi, Fumiyoshi; Mimori, Yasuyo; Miyachi, Takafumi; Ohshita, Tomohiko; Sasaki, Hideo

    2009-06-15

    Radiotherapy has been reported to cause neuropsychological dysfunction. Here we examined whether exposure to atomic bomb radiation affected the incidence of dementia among 2286 atomic bomb survivors and controls - all members of the Adult Health Study cohort. Study subjects were non-demented and aged >or=60 years at baseline examination and had been exposed in 1945 at >or=13 years of age to a relatively low dose (radiation on the dementia incidence rate, we applied Poisson regression analysis. Incidence per 1000 person-years was 16.3 in the <5 mGy group, 17.0 in the 5-499 mGy group, and 15.2 in the >or=500 mGy group. Alzheimer disease was the predominant type of dementia in each dose category. After adjustment for potential risk factors, radiation exposure did not affect the incidence rate of either all dementia or any of its subtypes. No case of dementia had a history of therapeutic cranial irradiation. Although we found no relationship between radiation exposure and the development of dementia among atomic bomb survivors exposed at >or=13 years old in this longitudinal study, effects on increased risk of early death among atomic bomb survivors will be considered.

  14. Dosimetry of Atomic Bomb Radiation in Hiroshima by Thermoluminescence of Roof Tiles.

    PubMed

    Higashimura, T; Ichikawa, Y; Sidei, T

    1963-03-29

    Thermoluminescence dosimetry is a powerful tool for obtaining the distribution of gamma dose, heretofore unknown, from the atomic bombs dropped on Hiroshima and Nagasaki. Roof tiles irradiated by the bombs show intense thermoluminescence, and the radiation dose for samples irradiated below 100 r by the bomb can be measured by this method.

  15. Low Earth orbital atomic oxygen and ultraviolet radiation effects on polymers

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.

    1991-01-01

    Because atomic oxygen and solar ultraviolet radiation present in the low earth orbital (LEO) environment can alter the chemistry of polymers resulting in degradation, their effects and mechanisms of degradation must be determined in order to determine the long term durability of polymeric surfaces to be exposed on missions such as Space Station Freedom. The effects of atomic oxygen on polymers which contain protective coatings must also be explored, since unique damage mechanisms can occur in areas where the protective coatings has failed. Mechanisms can be determined by utilizing results from previous LEO missions, by performing ground based LEO simulation tests and analysis, and by carrying out focussed space experiments. A survey is presented of the interactions and possible damage mechanisms for environmental atomic oxygen and UV radiation exposure of polymers commonly used in LEO.

  16. Coherent dynamics of Rydberg atoms in cosmic-microwave-background radiation

    NASA Astrophysics Data System (ADS)

    Tscherbul, Timur V.; Brumer, Paul

    2014-01-01

    Rydberg atoms excited by cold blackbody radiation are shown to display long-lived quantum coherences on time scales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix and demonstrate that the blackbody-induced temporal coherences manifest as slowly decaying (100 ps) quantum beats in time-resolved fluorescence. An analytic model shows the dependence of the coherent dynamics on the energy splitting between atomic eigenstates, transition dipole moments, and coherence time of the radiation. Experimental detection of the fluorescence signal from a trapped ensemble of 108 Rydberg atoms is discussed, but shown to be technically challenging at present, requiring cosmic-microwave-background amplification somewhat beyond current practice.

  17. Classical Zero-Point Radiation and Relativity: The Problem of Atomic Collapse Revisited

    NASA Astrophysics Data System (ADS)

    Boyer, Timothy H.

    2016-07-01

    The physicists of the early twentieth century were unaware of two aspects which are vital to understanding some aspects of modern physics within classical theory. The two aspects are: (1) the presence of classical electromagnetic zero-point radiation, and (2) the importance of special relativity. In classes in modern physics today, the problem of atomic collapse is still mentioned in the historical context of the early twentieth century. However, the classical problem of atomic collapse is currently being treated in the presence of classical zero-point radiation where the problem has been transformed. The presence of classical zero-point radiation indeed keeps the electron from falling into the Coulomb potential center. However, the old collapse problem has been replaced by a new problem where the zero-point radiation may give too much energy to the electron so as to cause "self-ionization." Special relativity may play a role in understanding this modern variation on the atomic collapse problem, just as relativity has proved crucial for a classical understanding of blackbody radiation.

  18. The effects of atomic oxygen on the thermal emittance of high temperature radiator surfaces

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Hotes, Deborah L.; Paulsen, Phillip E.

    1989-01-01

    Radiator surfaces on high temperature space power systems such as SP-100 space nuclear power system must maintain a high emittance level in order to reject waste heat effectively. One of the primary materials under consideration for the radiators is carbon-carbon composite. Since carbon is susceptible to attack by atomic oxygen in the low earth orbital environment, it is important to determine the durability of carbon composites in this environment as well as the effect atomic oxygen has on the thermal emittance of the surface if it is to be considered for use as a radiator. Results indicate that the thermal emittance of carbon-carbon composite (as low as 0.42) can be enhanced by exposure to a directed beam of atomic oxygen to levels above 0.85 at 800 K. This emittance enhancement is due to a change in the surface morphology as a result of oxidation. High aspect ratio cones are formed on the surface which allow more efficient trapping of incident radiation. Erosion of the surface due to oxidation is similar to that for carbon, so that at altitudes less than approximately 600 km, thickness loss of the radiator could be significant (as much as 0.1 cm/year). A protective coating or oxidation barrier forming additive may be needed to prevent atomic oxygen attack after the initial high emittance surface is formed. Textured surfaces can be formed in ground based facilities or possibly in space if emittance is not sensitive to the orientation of the atomic oxygen arrival that forms the texture.

  19. The effects of atomic oxygen on the thermal emittance of high temperature radiator surfaces

    SciTech Connect

    Rutledge, S.K.; Hotes, D.L.; Paulsen, P.E.

    1994-09-01

    Radiator surfaces on high temperature space power systems such as the SP-100 space nuclear power system must maintain a high emittance level in order to reject waste heat effectively. one of the primary materials under consideration for the radiators is carbon-carbon composite. Since carbon is susceptible to attack by atomic oxygen in the low Earth orbital environment, it is important to determine the durability of carbon composites in this environment as well as the effect atomic oxygen has on the thermal emittance of the surface if it is to be considered for use as a radiator. Results indicate that the thermal emittance of carbon-carbon composite (as low as 0.42) can be enhanced by exposure to a directed beam of atomic oxygen to levels above 0.85 at 800 K. This emittance enhancement is due to a change in the surface morphology as a result of oxidation. High aspect ratio cones are formed on the surface which allow more efficient trapping of incident radiation. Erosion of the surface due to oxidation is similar to that for carbon; so that at altitudes less than {approximately}600 km, thickness loss of the radiator could be significant (as much as 0.1 cm/year). A protective coating or oxidation barrier forming additive may be needed to prevent atomic oxygen attack after the initial high emittance surface is formed. Textured surfaces can be formed in ground based facilities or possibly in space if emittance is not sensitive to the orientation of the atomic oxygen arrival that forms the texture.

  20. Ground radiation tests and flight atomic oxygen tests of ITO protective coatings for Galileo Spacecraft

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.; Maag, Carl R.

    1986-01-01

    Radiation simulation tests (protons and electrons) were performed along with atomic oxygen flight tests aboard the Shuttle to space qualify the surface protective coatings. The results, which contributed to the selection of indium-tin-oxide (ITO) coated polyester as the material for the thermal blankets of the Galileo Spacecraft, are given here. Two candidate materials, polyester and Fluorglas, were radiation-tested to determine changes at simulated Jovian radiation levels. The polyester exhibited a smaller weight loss (2.8) than the Fluorglas (8.8 percent). Other changes of polyester are given. During low-earth orbit, prior to transit to Jupiter, the thermal blankets would be exposed to atomic oxygen. Samples of uncoated and ITO-coated polyesters were flown on the Shuttle. Qualitative results are given which indicated that the ITO coating protected the underlying polyester.

  1. Mathematical phantoms for use in reassessment of radiation doses to Japanese atomic-bomb survivors

    SciTech Connect

    Cristy, M.

    1985-07-01

    In 1972 committees of the United Nations and the US National Academy of Sciencs emphasized the need for organ dose estimates on the Japanese atomic-bomb survivors. These estimates were then supplied by workers in Japan and the US, and they were used with the so-called T65D estimates of a survivor's radiation exposure to assess risk from radiation. Recently the T65D estimates have been questioned, and programs for reassessment of atomic-bomb radiation dosimetry have been started in Japan and the US. As a part of this new effort a mathematical analogue of the human body (or ''mathematical phantom''), to be used in estimating organ doses in adult survivors, is presented here. Recommendations on organ dosimetry for juvenile survivors are also presented and discussed. 57 refs., 10 figs., 6 tabs.

  2. Vacuum ultraviolet radiation/atomic oxygen synergism in fluorinated ethylene propylene Teflon erosion

    NASA Technical Reports Server (NTRS)

    Stiegman, A. E.; Brinza, David E.; Laue, Eric G.; Anderson, Mark S.; Liang, Ranty H.

    1992-01-01

    A micrographic investigation is reported of samples of the fluorinated ethylene propylene (FEP) Teflon thermal-blanketing materials recovered from the Long-Duration Exposure Facility (LDEF) satellite. The samples are taken from the trailing edge and row 8 which correspond to exposures to vacuum UV (VUV) and VUV + atomic O, respectively. Data are taken from SEM and IR-spectra observations, and the LDEF leading-edge FEP shows a high degree of erosion, roughening, and sharp peaks angled in the direction of the flow of atomic O. The trailing edge sample influenced primarily by VUV shows a hard brittle layer and some cracked mosaic patterns. Comparisons to a reference sample suggest that the brittle layer is related to exposure to VUV and is removed by atomic-O impingement. Polymers that are stable to VUV radiation appear to be more stable in terms of atomic oxygen.

  3. Effects of IL-10 haplotype and atomic bomb radiation exposure on gastric cancer risk.

    PubMed

    Hayashi, Tomonori; Ito, Reiko; Cologne, John; Maki, Mayumi; Morishita, Yukari; Nagamura, Hiroko; Sasaki, Keiko; Hayashi, Ikue; Imai, Kazue; Yoshida, Kengo; Kajimura, Junko; Kyoizumi, Seishi; Kusunoki, Yoichiro; Ohishi, Waka; Fujiwara, Saeko; Akahoshi, Masazumi; Nakachi, Kei

    2013-07-01

    Gastric cancer (GC) is one of the cancers that reveal increased risk of mortality and incidence in atomic bomb survivors. The incidence of gastric cancer in the Life Span Study cohort of the Radiation Effects Research Foundation (RERF) increased with radiation dose (gender-averaged excess relative risk per Gy = 0.28) and remains high more than 65 years after exposure. To assess a possible role of gene-environment interaction, we examined the dose response for gastric cancer incidence based on immunosuppression-related IL-10 genotype, in a cohort study with 200 cancer cases (93 intestinal, 96 diffuse and 11 other types) among 4,690 atomic bomb survivors participating in an immunological substudy. Using a single haplotype block composed of four haplotype-tagging SNPs (comprising the major haplotype allele IL-10-ATTA and the minor haplotype allele IL-10-GGCG, which are categorized by IL-10 polymorphisms at -819A>G and -592T>G, +1177T>C and +1589A>G), multiplicative and additive models for joint effects of radiation and this IL-10 haplotyping were examined. The IL-10 minor haplotype allele(s) was a risk factor for intestinal type gastric cancer but not for diffuse type gastric cancer. Radiation was not associated with intestinal type gastric cancer. In diffuse type gastric cancer, the haplotype-specific excess relative risk (ERR) for radiation was statistically significant only in the major homozygote category of IL-10 (ERR = 0.46/Gy, P = 0.037), whereas estimated ERR for radiation with the minor IL-10 homozygotes was close to 0 and nonsignificant. Thus, the minor IL-10 haplotype might act to reduce the radiation related risk of diffuse-type gastric cancer. The results suggest that this IL-10 haplotyping might be involved in development of radiation-associated gastric cancer of the diffuse type, and that IL-10 haplotypes may explain individual differences in the radiation-related risk of gastric cancer.

  4. The application of quasi-steady approximation in atomic kinetics in simulation of hohlraum radiation drive

    NASA Astrophysics Data System (ADS)

    Ren, Guoli; Pei, Wenbing; Lan, Ke; Li, Xin; Hohlraum Physics Team

    2014-10-01

    In current routine 2D simulation of hohlraum physics, we adopt the principal-quantum-number (n-level) average atom model (AAM) in NLTE plasma description. The more sophisticated atomic kinetics description is better choice, but the in-line calculation consumes much more resource. By distinguishing the much more fast bound-bound atomic processes from the relative slow bound-free atomic processes, we found a method to built up a bound electron distribution (n-level or nl-level) using in-line n-level calculated plasma condition (such as temperature, density, average ionization degree). We name this method ``quasi-steady approximation.'' Using this method and the plasma condition calculated under n-level, we re-build the nl-level bound electron distribution (Pnl), and acquire a new hohlraum radiative drive by post-processing. Comparison with the n-level post-processed hohlraum drive shows that we get an almost identical radiation flux but with more-detailed frequency-dependant structures. Also we use this method in the benchmark gold sphere experiment, the constructed nl-level radiation drive resembles the experimental results and DCA results, while the n-level raditation does not.

  5. Generation of a fast atomic-oxygen beam from O - ions by resonant cavity radiation

    NASA Astrophysics Data System (ADS)

    Stephen, T. M.; Van Zyl, B.; Amme, R. C.

    1996-04-01

    An apparatus has been developed for producing a beam of ground-electronic-state oxygen atoms with energies variable from 4 to 1000 eV with a 1.5 eV FWHM energy distribution. The technique involves extraction of negative ions from a low-voltage gas-discharge source, mass selection of the extracted O- with a Wien-type velocity filter, O- acceleration or deceleration and focusing by electrostatic ion optics, and electron detachment from O- by intracavity laser radiation. A 25 W argon-ion-laser cavity has been extended to include the ion-beam vacuum chamber so that the intracavity radiation intersects the O- ion trajectories normally. Depending on the laser configuration in use, ion-neutralization efficiencies between 5% and 25% have been achieved at 5 eV O- energy. Thus, 5 eV O-atom fluxes of ˜1011 atoms/s (˜1012 atoms/cm2 s) have been achieved for O- currents of ˜10-7 A. The advantages and limitations of the technique are discussed, and preliminary measurements of the secondary-negative-charge production from low-energy O-atom impact on copper and stainless-steel surfaces are presented.

  6. Evidence supporting radiation hormesis in atomic bomb survivor cancer mortality data.

    PubMed

    Doss, Mohan

    2012-12-01

    A recent update on the atomic bomb survivor cancer mortality data has concluded that excess relative risk (ERR) for solid cancers increases linearly with dose and that zero dose is the best estimate for the threshold, apparently validating the present use of the linear no threshold (LNT) model for estimating the cancer risk from low dose radiation. A major flaw in the standard ERR formalism for estimating cancer risk from radiation (and other carcinogens) is that it ignores the potential for a large systematic bias in the measured baseline cancer mortality rate, which can have a major effect on the ERR values. Cancer rates are highly variable from year to year and between adjacent regions and so the likelihood of such a bias is high. Calculations show that a correction for such a bias can lower the ERRs in the atomic bomb survivor data to negative values for intermediate doses. This is consistent with the phenomenon of radiation hormesis, providing a rational explanation for the decreased risk of cancer observed at intermediate doses for which there is no explanation based on the LNT model. The recent atomic bomb survivor data provides additional evidence for radiation hormesis in humans.

  7. Impact on the Japanese atomic bomb survivors of radiation received from the bombs.

    PubMed

    Cullings, Harry M

    2014-02-01

    The Radiation Effects Research Foundation (RERF) studies various cohorts of Japanese atomic bomb survivors, the largest being the Life Span Study (LSS), which includes 93,741 persons who were in Hiroshima or Nagasaki at the times of the bombings; there are also cohorts of persons who were exposed in utero and survivors' children. This presentation attempts to summarize the total impact of the radiation from the bombs on the survivors from both an individual perspective (both age-specific and integrated lifetime risk, along with a measure of life expectancy that describes how the risk affects the individual given age at exposure) and a group perspective (estimated numbers of excess occurrences in the cohort), including both early and late effects. As survivors' doses ranged well into the acutely lethal range at closer distances, some of them experienced acute signs and symptoms of radiation exposure in addition to being at risk of late effects. Although cancer has always been a primary concern among late effects, estimated numbers of excess cancers and hematopoietic malignancies in the LSS are a small fraction of the total due to the highly skewed dose distribution, with most survivors receiving small doses. For example, in the latest report on cancer incidence, 853 of 17,448 incident solid cancers were estimated to be attributable to radiation from the bombs. RERF research indicates that risk of radiation-associated cancer varies among sites and that some benign tumors such as uterine myoma are also associated with radiation. Noncancer late effects appear to be in excess in proportion to radiation dose but with an excess relative risk about one-third that of solid cancer and a correspondingly small overall fraction of cases attributable to radiation. Specific risks were found for some subcategories, particularly circulatory disease, including stroke and precedent conditions such as hypertension. Radiation-related cataract in the atomic bomb survivors is well known

  8. Impact on the Japanese atomic bomb survivors of radiation received from the bombs.

    PubMed

    Cullings, Harry M

    2014-02-01

    The Radiation Effects Research Foundation (RERF) studies various cohorts of Japanese atomic bomb survivors, the largest being the Life Span Study (LSS), which includes 93,741 persons who were in Hiroshima or Nagasaki at the times of the bombings; there are also cohorts of persons who were exposed in utero and survivors' children. This presentation attempts to summarize the total impact of the radiation from the bombs on the survivors from both an individual perspective (both age-specific and integrated lifetime risk, along with a measure of life expectancy that describes how the risk affects the individual given age at exposure) and a group perspective (estimated numbers of excess occurrences in the cohort), including both early and late effects. As survivors' doses ranged well into the acutely lethal range at closer distances, some of them experienced acute signs and symptoms of radiation exposure in addition to being at risk of late effects. Although cancer has always been a primary concern among late effects, estimated numbers of excess cancers and hematopoietic malignancies in the LSS are a small fraction of the total due to the highly skewed dose distribution, with most survivors receiving small doses. For example, in the latest report on cancer incidence, 853 of 17,448 incident solid cancers were estimated to be attributable to radiation from the bombs. RERF research indicates that risk of radiation-associated cancer varies among sites and that some benign tumors such as uterine myoma are also associated with radiation. Noncancer late effects appear to be in excess in proportion to radiation dose but with an excess relative risk about one-third that of solid cancer and a correspondingly small overall fraction of cases attributable to radiation. Specific risks were found for some subcategories, particularly circulatory disease, including stroke and precedent conditions such as hypertension. Radiation-related cataract in the atomic bomb survivors is well known

  9. Deuterium removal from radiation damage in tungsten by isotopic exchange with hydrogen atomic beam

    NASA Astrophysics Data System (ADS)

    Ogorodnikova, O. V.; Markelj, S.; Efimov, V. S.; Gasparyan, Yu M.

    2016-09-01

    The tungsten samples were pre-irradiated with self-ions to create radiation-induced defects and then exposed to the deuterium atomic beam. The deuterium removal was studied by isotopic exchange with atomic hydrogen beam. Modification of the deuterium depth profile in self-ion irradiated tungsten under isotopic exchange up to a depth of 6 μm was measured in- situ by nuclear reaction analysis. The total deuterium retention after isotopic exchange was measured by thermal desorption spectroscopy. It is shown that the efficiency of the deuterium removal increases with increasing of the hydrogen incident flux, incident energy and temperature of the tungsten sample.

  10. Radionuclide detection by inductively coupled plasma mass spectrometry: A comparison of atomic and radiation detection method

    SciTech Connect

    Smith, M.R.; Wyse, E.J.; Koppenaal, D.W.

    1991-04-01

    Radionuclide detection by mass spectrometric techniques offers inherent advantages over conventional radiation detection methods. Since radionuclides decay at variable rates (half-lives) and via various nuclear transformations (i.e. emission of alpha, beta, and/or gamma radiation) their determination via radiation detection depends not only on decay systematics but also on detector technology. Radionuclide detection by direct atom measurement, however, is dependent only on technique sensitivity and is indifferent to decay mode. Evaluation of inductively coupled plasma mass spectrometry (ICP/MS) indicates this method to be superior conventional radiation detection techniques for many radionuclides. This work discusses factors which influence detection by both methods. Illustrative applications of ICP/MS to the ultra-trace determination of several radionuclides, including {sup 129}I, are presented. 20 refs., 6 figs., 1 tab.

  11. Optical radiation from the interaction of energetic atoms, ions, electrons, and photons with surfaces

    NASA Technical Reports Server (NTRS)

    Tolk, N. H.; Albridge, R. G.; Haglund, R. F., Jr.; Mendenhall, M. H.

    1985-01-01

    Heavy particle, electron, and UV photon bombardment of solid surfaces has been recently observed to result in the emission of infrared, visible, and ultraviolet radiation. This effect occurs over a wide range of incident projectile energies. Line radiation arising from transitions between discrete atomic or molecular levels may be attributed to the decay of excited particles which have been sputtered or electronically/chemically desorbed from the surface. Broadband continuum radiation, which is also observed, is believed to arise either from fluorescence of the near surface bulk or from the radiative decay of desorbed excited clusters. Spacecraft, in the ambient near Earth environment, are subject to such bombardment. The dynamics of energetic particle and photon beam interactions with surfaces which lead to surface erosion and glow phenomena will be treated. In addition, projected experimental and theoretical studies of oxygen and nitrogen beam surface interactions on materials characteristic of spacecraft surfaces will be discussed.

  12. Theoretical Modeling of Radiation-driven Atomic Kinetics of a Neon Photoionized Plasma

    NASA Astrophysics Data System (ADS)

    Durmaz, Tunay

    We report on a theoretical study on atomic kinetics modeling of a photoionized neon plasma at conditions relevant to laboratory experiments performed at the Z-machine in Sandia National Laboratories. We describe an atomic kinetics model and code, ATOKIN, that was developed and used to compute the atomic level population distribution. The study includes atomic level sensitivity with respect to energy level structure, radiation and transient effects, electron temperature and x-ray drive sensitivity and an idea for electron temperature extraction from a level population ratio. The neon atomic model considers several ionization stages of highly-charged neon ions as well as a detailed structure of non-autoionizing and autoionizing energy levels in each ion. In the energy level sensitivity study, the atomic model was changed by adding certain types of energy levels such as singly-excited, auto-ionizing doubly-excited states. Furthermore, these levels were added ion by ion for the most populated ions. Atomic processes populating and de-populating the energy levels consider photoexcitation and photoionization due to the external radiation flux, and spontaneous and collisional atomic processes including plasma radiation trapping. Relevant atomic cross sections and rates were computed with the atomic structure and scattering FAC code. The calculations were performed at constant particle number density and driven by the time-histories of temperature and external radiation flux. These conditions were selected in order to resemble those achieved in photoionized plasma experiments at the Z facility of Sandia National Laboratories. For the same set of time histories, calculations were done in a full time-dependent mode and also as a sequence of instantaneous, steady states. Differences between both calculations are useful to identify transient effects in the ionization and atomic kinetics of the photoionized plasma, and its dependence on the atomic model and plasma environmental

  13. Inner-shell photoemission from atoms and molecules using synchrotron radiation

    SciTech Connect

    Lindle, D.W.

    1983-12-01

    Photoelectron spectroscopy, in conjunction with synchrotron radiation, has been used to study inner-shell photoemission from atoms and molecules. The time structure of the synchrotron radiation permits the measurements of time-of-flight (TOF) spectra of Auger and photoelectrons, thereby increasing the electron collection efficiency. The double-angle TOF method yielded angle-resolved photoelectron intensities, which were used to determine photoionization cross sections and photoelectron angular distributions in several cases. Comparison to theoretical calculations has been made where possible to help explain observed phenomena in terms of the electronic structure and photoionization dynamics of the systems studied. 154 references, 23 figures, 7 tables.

  14. Experimental Demonstration of Synthetic Lorentz Force on Cold Atoms by Using Radiation Pressure

    NASA Astrophysics Data System (ADS)

    Ban, Ticijana; Santic, Neven; Dubcek, Tena; Aumiler, Damir; Buljan, Hrvoje

    2015-05-01

    The quest for synthetic magnetism in quantum degenerate atomic gases is motivated by producing controllable quantum emulators, which could mimic complex quantum systems such as interacting electrons in magnetic fields. Experiments on synthetic magnetic fields for neutral atoms have enabled realization of the Hall effect, Harper and Haldane Hamiltonians, and other intriguing topological effects. Here we present the first demonstration of a synthetic Lorentz force, based on the radiation pressure and the Doppler effect, in cold atomic gases captured in a Magneto-Optical Trap (MOT). Synthetic Lorentz force on cold atomic cloud is measured by recording the cloud trajectory. The observed force is perpendicular to the cloud velocity, and it is zero for the atomic cloud at rest. The proposed concept is straightforward to implement in a large volume and different geometries, it is applicable for a broad range of velocities, and it can be realized for different atomic species. The experiment is based on the theoretical proposal introduced in. This work was supported by the UKF Grant No. 5/13 and Croatian MZOS.

  15. Identifying and quantifying radiation damage at the atomic level

    PubMed Central

    Gerstel, Markus; Deane, Charlotte M.; Garman, Elspeth F.

    2015-01-01

    Radiation damage impedes macromolecular diffraction experiments. Alongside the well known effects of global radiation damage, site-specific radiation damage affects data quality and the veracity of biological conclusions on protein mechanism and function. Site-specific radiation damage follows a relatively predetermined pattern, in that different structural motifs are affected at different dose regimes: in metal-free proteins, disulfide bonds tend to break first followed by the decarboxylation of aspartic and glutamic acids. Even within these damage motifs the decay does not progress uniformly at equal rates. Within the same protein, radiation-induced electron density decay of a particular chemical group is faster than for the same group elsewhere in the protein: an effect known as preferential specific damage. Here, B Damage, a new atomic metric, is defined and validated to recognize protein regions susceptible to specific damage and to quantify the damage at these sites. By applying B Damage to a large set of known protein structures in a statistical survey, correlations between the rates of damage and various physicochemical parameters were identified. Results indicate that specific radiation damage is independent of secondary protein structure. Different disulfide bond groups (spiral, hook, and staple) show dissimilar radiation damage susceptibility. There is a consistent positive correlation between specific damage and solvent accessibility. PMID:25723922

  16. Atomic orientation driven by broadly-frequency-modulated radiation: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Bevilacqua, G.; Biancalana, V.; Dancheva, Y.

    2016-07-01

    We investigate magnetic resonances driven in thermal vapor of alkali-metal atoms by laser radiation broadly modulated at a frequency resonant with the Zeeman splitting. A model accounting for both hyperfine and Zeeman pumping is developed, and its results are compared with experimental measurements performed at relatively weak pump irradiance. The interplay between the two pumping processes generates intriguing interaction conditions, often overlooked by simplified models.

  17. Coupling of an average-atom model with a collisional-radiative equilibrium model

    SciTech Connect

    Faussurier, G. Blancard, C.; Cossé, P.

    2014-11-15

    We present a method to combine a collisional-radiative equilibrium model and an average-atom model to calculate bound and free electron wavefunctions in hot dense plasmas by taking into account screening. This approach allows us to calculate electrical resistivity and thermal conductivity as well as pressure in non local thermodynamic equilibrium plasmas. Illustrations of the method are presented for dilute titanium plasma.

  18. Atomic collisions in the presence of laser radiation: Time dependence and the asymptotic wave function

    SciTech Connect

    DeVries, P.L.; George, T.F.

    1982-09-01

    A time-dependent, wave-packet description of atomic collisions in the presence of laser radiation is extracted from the more conventional time-independent, stationary-state description. This approach resolves certain difficulties of interpretation in the time-independent approach which arise in the case of asymptotic near resonance. In the two-state model investigated, the approach predicts the existence of three spherically scattered waves in this asymtotically near-resonant case.

  19. Atomic collisions in the presence of laser radiation - Time dependence and the asymptotic wave function

    NASA Technical Reports Server (NTRS)

    Devries, P. L.; George, T. F.

    1982-01-01

    A time-dependent, wave-packet description of atomic collisions in the presence of laser radiation is extracted from the more conventional time-independent, stationary-state description. This approach resolves certain difficulties of interpretation in the time-independent approach which arise in the case of asymptotic near resonance. In the two-state model investigated, the approach predicts the existence of three spherically scattered waves in this asymptotically near-resonant case.

  20. Incidence of dementia among atomic-bomb survivors--Radiation Effects Research Foundation Adult Health Study.

    PubMed

    Yamada, Michiko; Kasagi, Fumiyoshi; Mimori, Yasuyo; Miyachi, Takafumi; Ohshita, Tomohiko; Sasaki, Hideo

    2009-06-15

    Radiotherapy has been reported to cause neuropsychological dysfunction. Here we examined whether exposure to atomic bomb radiation affected the incidence of dementia among 2286 atomic bomb survivors and controls - all members of the Adult Health Study cohort. Study subjects were non-demented and aged >or=60 years at baseline examination and had been exposed in 1945 at >or=13 years of age to a relatively low dose (radiation on the dementia incidence rate, we applied Poisson regression analysis. Incidence per 1000 person-years was 16.3 in the <5 mGy group, 17.0 in the 5-499 mGy group, and 15.2 in the >or=500 mGy group. Alzheimer disease was the predominant type of dementia in each dose category. After adjustment for potential risk factors, radiation exposure did not affect the incidence rate of either all dementia or any of its subtypes. No case of dementia had a history of therapeutic cranial irradiation. Although we found no relationship between radiation exposure and the development of dementia among atomic bomb survivors exposed at >or=13 years old in this longitudinal study, effects on increased risk of early death among atomic bomb survivors will be considered. PMID:19327783

  1. Radiation and smoking effects on lung cancer incidence by histological types among atomic bomb survivors.

    PubMed

    Egawa, Hiromi; Furukawa, Kyoji; Preston, Dale; Funamoto, Sachiyo; Yonehara, Shuji; Matsuo, Takeshi; Tokuoka, Shoji; Suyama, Akihiko; Ozasa, Kotaro; Kodama, Kazunori; Mabuchi, Kiyohiko

    2012-09-01

    While the risk of lung cancer associated separately with smoking and radiation exposure has been widely reported, it is not clear how smoking and radiation together contribute to the risk of specific lung cancer histological types. With individual smoking histories and radiation dose estimates, we characterized the joint effects of radiation and smoking on type-specific lung cancer rates among the Life Span Study cohort of Japanese atomic bomb survivors. Among 105,404 cohort subjects followed between 1958 and 1999, 1,803 first primary lung cancer incident cases were diagnosed and classified by histological type. Poisson regression methods were used to estimate excess relative risks under several interaction models. Adenocarcinoma (636 cases), squamous-cell carcinoma (330) and small-cell carcinoma (194) made up 90% of the cases with known histology. Both smoking and radiation exposure significantly increased the risk of each major lung cancer histological type. Smoking-associated excess relative risks were significantly larger for small-cell and squamous-cell carcinomas than for adenocarcinoma. The gender-averaged excess relative risks per 1 Gy of radiation (for never-smokers at age 70 after radiation exposure at age 30) were estimated as 1.49 (95% confidence interval 0.1-4.6) for small-cell carcinoma, 0.75 (0.3-1.3) for adenocarcinoma, and 0.27 (0-1.5) for squamous-cell carcinoma. Under a model allowing radiation effects to vary with levels of smoking, the nature of the joint effect of smoking and radiation showed a similar pattern for different histological types in which the radiation-associated excess relative risk tended to be larger for moderate smokers than for heavy smokers. However, in contrast to analyses of all lung cancers as a group, such complicated interactions did not describe the data significantly better than either simple additive or multiplicative interaction models for any of the type-specific analyses.

  2. Radiation and Smoking Effects on Lung Cancer Incidence by Histological Types Among Atomic Bomb Survivors

    PubMed Central

    Egawa, Hiromi; Furukawa, Kyoji; Preston, Dale; Funamoto, Sachiyo; Yonehara, Shuji; Matsuo, Takeshi; Tokuoka, Shoji; Suyama, Akihiko; Ozasa, Kotaro; Kodama, Kazunori; Mabuchi, Kiyohiko

    2014-01-01

    While the risk of lung cancer associated separately with smoking and radiation exposure has been widely reported, it is not clear how smoking and radiation together contribute to the risk of specific lung cancer histological types. With individual smoking histories and radiation dose estimates, we characterized the joint effects of radiation and smoking on type-specific lung cancer rates among the Life Span Study cohort of Japanese atomic bomb survivors. Among 105,404 cohort subjects followed between 1958 and 1999, 1,803 first primary lung cancer incident cases were diagnosed and classified by histological type. Poisson regression methods were used to estimate excess relative risks under several interaction models. Adenocarcinoma (636 cases), squamous-cell carcinoma (330) and small-cell carcinoma (194) made up 90% of the cases with known histology. Both smoking and radiation exposure significantly increased the risk of each major lung cancer histological type. Smoking-associated excess relative risks were significantly larger for small-cell and squamous-cell carcinomas than for adenocarcinoma. The gender-averaged excess relative risks per 1 Gy of radiation (for never-smokers at age 70 after radiation exposure at age 30) were estimated as 1.49 (95% confidence interval 0.1–4.6) for small-cell carcinoma, 0.75 (0.3–1.3) for adenocarcinoma, and 0.27 (0–1.5) for squamous-cell carcinoma. Under a model allowing radiation effects to vary with levels of smoking, the nature of the joint effect of smoking and radiation showed a similar pattern for different histological types in which the radiation-associated excess relative risk tended to be larger for moderate smokers than for heavy smokers. However, in contrast to analyses of all lung cancers as a group, such complicated interactions did not describe the data significantly better than either simple additive or multiplicative interaction models for any of the type-specific analyses. PMID:22862780

  3. Radiation and smoking effects on lung cancer incidence by histological types among atomic bomb survivors.

    PubMed

    Egawa, Hiromi; Furukawa, Kyoji; Preston, Dale; Funamoto, Sachiyo; Yonehara, Shuji; Matsuo, Takeshi; Tokuoka, Shoji; Suyama, Akihiko; Ozasa, Kotaro; Kodama, Kazunori; Mabuchi, Kiyohiko

    2012-09-01

    While the risk of lung cancer associated separately with smoking and radiation exposure has been widely reported, it is not clear how smoking and radiation together contribute to the risk of specific lung cancer histological types. With individual smoking histories and radiation dose estimates, we characterized the joint effects of radiation and smoking on type-specific lung cancer rates among the Life Span Study cohort of Japanese atomic bomb survivors. Among 105,404 cohort subjects followed between 1958 and 1999, 1,803 first primary lung cancer incident cases were diagnosed and classified by histological type. Poisson regression methods were used to estimate excess relative risks under several interaction models. Adenocarcinoma (636 cases), squamous-cell carcinoma (330) and small-cell carcinoma (194) made up 90% of the cases with known histology. Both smoking and radiation exposure significantly increased the risk of each major lung cancer histological type. Smoking-associated excess relative risks were significantly larger for small-cell and squamous-cell carcinomas than for adenocarcinoma. The gender-averaged excess relative risks per 1 Gy of radiation (for never-smokers at age 70 after radiation exposure at age 30) were estimated as 1.49 (95% confidence interval 0.1-4.6) for small-cell carcinoma, 0.75 (0.3-1.3) for adenocarcinoma, and 0.27 (0-1.5) for squamous-cell carcinoma. Under a model allowing radiation effects to vary with levels of smoking, the nature of the joint effect of smoking and radiation showed a similar pattern for different histological types in which the radiation-associated excess relative risk tended to be larger for moderate smokers than for heavy smokers. However, in contrast to analyses of all lung cancers as a group, such complicated interactions did not describe the data significantly better than either simple additive or multiplicative interaction models for any of the type-specific analyses. PMID:22862780

  4. 'A dispassionate and objective effort:' negotiating the first study on the Biological Effects of Atomic Radiation.

    PubMed

    Hamblin, Jacob Darwin

    2007-01-01

    The National Academy of Science's 1956 study on the Biological Effects of Atomic Radiation (BEAR) was designed to provide an objective analysis to assess conflicting statements by leading geneticists and by officials in the Atomic Energy Commission. Largely because of its status as a detached, non-governmental evaluation by eminent scientists, no studies have had a broader impact on the development of biological thinking in regard to nuclear policies. This paper demonstrates that despite the first BEAR study's reputation as an objective and independent study, it was the product of careful negotiation between Academy scientists, the Atomic Energy Commission, and Britain's Medical Research Council. This paper also reveals the fragility of the consensus that produced the Academy's report, the range of political uses of the report, and the subsequent disaffection of the scientists who took part in it. PMID:17993170

  5. Nonlinear polarization response of a gaseous medium in the regime of atom stabilization in a strong radiation field

    SciTech Connect

    Volkova, E. A.; Popov, A. M. Tikhonova, O. V.

    2013-03-15

    The nonlinear polarization response of a quantum system modeling a silver atom in the field of high-intensity radiation in the IR and UV spectral ranges has been studied by direct numerical integration of a nonstationary Schroedinger equation. The domains of applicability of perturbation theory and polarization expansion in powers of the field intensity are determined. The contribution of excited atoms and electrons in a continuum to the atomic polarization response at the field frequency, which arises due to the radiation-induced excitation and photoionization processes, is analyzed. Features of the nonlinear response to an external field under conditions of atom stabilization are considered.

  6. The neoplastic transformation potential of mammography X rays and atomic bomb spectrum radiation.

    PubMed

    Heyes, G J; Mill, A J

    2004-08-01

    Considerable controversy currently exists regarding the biological effectiveness of 29 kVp X rays which are used for mammography screening. This issue must be resolved to enable proper evaluation of radiation risks from breast screening. Here a definitive assessment of the biological effectiveness of 29 kVp X rays compared to the quality of radiation to which the atomic bomb survivors were exposed is presented for the first time. The standard radiation sources used were (a) an atomic bomb simulation spectrum and (b) 2.2 MeV electrons from a strontium-90/yttrium-90 (90Sr/90Y) radioactive source. The biological end point used was neoplastic transformation in vitro in CGL1 (HeLa x human fibroblast hybrid) cells. No significant difference was observed for the biological effectiveness of the two high-energy sources for neoplastic transformation. A limiting relative biological effectiveness (RBE(M)) of 4.42 +/- 2.02 was observed for neoplastic transformation by 29 kVp X rays compared to these two sources. This compares with values of 4.67 +/- 3.93 calculated from previously published data and 3.58 +/- 1.77 when the reference radiation was 200 and 220 kVp X rays. This suggests that the risks associated with mammography screening may be approximately five times higher than previously assumed and that the risk-benefit relationship of mammography exposures may need to be re-examined. PMID:15387138

  7. Radiation and smoking effects on lung cancer incidence among atomic-bomb survivors

    PubMed Central

    Furukawa, Kyoji; Preston, Dale; Lönn, Stefan; Funamoto, Sachiyo; Yonehara, Shuji; Matsuo, Takeshi; Egawa, Hiromi; Tokuoka, Shoji; Ozasa, Kotaro; Kasagi, Fumiyoshi; Kodama, Kazunori; Mabuchi, Kiyohiko

    2013-01-01

    While radiation increases the risk of lung cancer among members of the Life Span Study (LSS) cohort of atomic-bomb survivors, there are still important questions about the nature of its interaction with smoking, the predominant cause of lung cancer. Among 105,404 LSS subjects, 1,803 primary lung cancer incident cases were identified for the period 1958–1999. Individual smoking history information and the latest radiation dose estimates were utilized to investigate the joint effects of radiation and smoking on lung cancer rates using Poisson grouped survival regression methods. Relative to never-smokers lung cancer risks increased with the amount and duration of smoking, and decreased with time since quitting smoking at any level of radiation exposure. Models assuming generalized interactions of smoking and radiation fit markedly better than simple additive or multiplicative interaction models. The joint effect appeared to be super-multiplicative for light/moderate-smokers, with a rapid increase in excess risk with smoking intensity up to about 10 cigarettes per day, but additive or sub-additive for heavy-smokers smoking a pack or more per day, with little indication of any radiation-associated excess risk. The gender-averaged excess relative risk per Gy of lung cancer (at age 70 after radiation exposure at 30) was estimated as 0.59 (95% confidence interval: 0.31–1.00) for non-smokers with a female:male ratio of 3.1. About one-third of the lung cancer cases in this cohort were estimated to be attributable to smoking while about 7% were associated with radiation. The joint effect of smoking and radiation on lung cancer in the LSS is dependent on smoking intensity, and best described by the generalized interaction model rather than a simple additive or multiplicative model. PMID:20681801

  8. Formation of molecular ions by radiative association of cold trapped atoms and ions

    NASA Astrophysics Data System (ADS)

    Dulieu, Olivier; da Silva, Humberto, Jr.; Aymar, Mireille; Raoult, Maurice

    2015-05-01

    Radiative emission during cold collisions between trapped laser-cooled Rb atoms and alkaline-earth ions (Ca+ , Sr+ , Ba+) and Yb+ are studied theoretically, using accurate effective-core-potential based quantum chemistry calculations of potential energy curves and transition dipole moments of the related molecular ions. Radiative association of molecular ions is predicted to occur for all systems with a cross section two to ten times larger than the radiative charge transfer one. Partial and total rate constants are also calculated and compared to available experiments. Narrow shape resonances are expected, which could be detectable at low temperature with an experimental resolution at the limit of the present standards. Vibrational distributions show that the final molecular ions are not created in their ground state level. Supported by the Marie-Curie ITN ``COMIQ: Cold Molecular Ions at the Quantum limit'' of the EU (#607491).

  9. Ordered many-electron motions in atoms and x-ray lasers. [Subpicosecond ultraviolet laser radiation

    SciTech Connect

    Rhodes, C.K.

    1986-01-01

    Subpicosecond ultraviolet laser technology is enabling the exploration of nonlinear atomic interactions with electric field strengths considerably in excess of an atomic unit. As this regime is approached, experiments studying multiple ionization, photoelectron energy spectra, and harmonically produced radiation all exhibit strong nonlinear coupling. Peak total energy transfer rates on the order of approx.2 x 10/sup -4/ W/atom have been observed at an intensity of approx.10/sup 16/ W/cm/sup 2/, and it is expected that energy transfer rates approaching approx.0.1 to 1 W/atom will occur under more extreme conditions for which the ultraviolet electric field E is significantly greater than e/a/sub 0//sup 2/. In this high intensity regime, a wide range of new nonlinear phenomena will be open to study. These will include the possibility of ordered driven motions in atoms, molecules, and plasmas, mechanisms involving collisions, and relativistic processes such as electron-positron pair production. An understanding of these physical interactions may provide a basis for the generation of stimulated emission in the x-ray range. 100 refs., 8 figs.

  10. Hepatocellular carcinoma among atomic bomb survivors: significant interaction of radiation with hepatitis C virus infections.

    PubMed

    Sharp, Gerald B; Mizuno, Terumi; Cologne, John B; Fukuhara, Toshiyuki; Fujiwara, Saeko; Tokuoka, Shoji; Mabuchi, Kiyohiko

    2003-02-10

    We conducted a nested case-control study within the cohort of Japanese survivors of the 1945 atomic bombings to study the joint effects of HBV and HCV with radiation on the risk of HCC. Among subjects who received autopsies during 1954-1988, we analyzed archival tissue samples for 238 pathologically confirmed HCC cases and 894 controls who died from diseases other than liver cancer. Using logistic regression and adjusting for potential confounders and other factors, we found a statistically significant, supermultiplicative interaction between A bomb radiation and HCV in the etiology of HCC. Compared to subjects who were negative for HCV and radiation, ORs of HCC for HCV-positive subjects showed a statistically significant, greater than multiplicative increase for liver irradiation exposures in the second (>0.018-0.186 Sv, p = 0.04) and third (>0.186 Sv, p = 0.05) tertiles of non-zero radiation exposure but not for first tertile exposure (>0-0.018 Sv, p = 0.86). Limiting analysis to subjects without cirrhosis, HCV-infected subjects were at 58.0-fold (95% CI 1.99- infinity ) increased risk of HCC per Sv of radiation exposure (p = 0.017), a supermultiplicative interaction between radiation and HCV that was not found among subjects with cirrhosis (p = 0.67). We found no evidence of interaction between HBV infection and radiation exposure in the etiology of HCC, regardless of cirrhosis status (p = 0.58). We conclude that among survivors of the nuclear bombings of Hiroshima and Nagasaki, subjects who were both HCV-positive and radiation-exposed were at a significantly, supermultiplicatively increased risk of HCC without concurrent cirrhosis.

  11. Effects of IL-10 haplotype and atomic bomb radiation exposure on gastric cancer risk.

    PubMed

    Hayashi, Tomonori; Ito, Reiko; Cologne, John; Maki, Mayumi; Morishita, Yukari; Nagamura, Hiroko; Sasaki, Keiko; Hayashi, Ikue; Imai, Kazue; Yoshida, Kengo; Kajimura, Junko; Kyoizumi, Seishi; Kusunoki, Yoichiro; Ohishi, Waka; Fujiwara, Saeko; Akahoshi, Masazumi; Nakachi, Kei

    2013-07-01

    Gastric cancer (GC) is one of the cancers that reveal increased risk of mortality and incidence in atomic bomb survivors. The incidence of gastric cancer in the Life Span Study cohort of the Radiation Effects Research Foundation (RERF) increased with radiation dose (gender-averaged excess relative risk per Gy = 0.28) and remains high more than 65 years after exposure. To assess a possible role of gene-environment interaction, we examined the dose response for gastric cancer incidence based on immunosuppression-related IL-10 genotype, in a cohort study with 200 cancer cases (93 intestinal, 96 diffuse and 11 other types) among 4,690 atomic bomb survivors participating in an immunological substudy. Using a single haplotype block composed of four haplotype-tagging SNPs (comprising the major haplotype allele IL-10-ATTA and the minor haplotype allele IL-10-GGCG, which are categorized by IL-10 polymorphisms at -819A>G and -592T>G, +1177T>C and +1589A>G), multiplicative and additive models for joint effects of radiation and this IL-10 haplotyping were examined. The IL-10 minor haplotype allele(s) was a risk factor for intestinal type gastric cancer but not for diffuse type gastric cancer. Radiation was not associated with intestinal type gastric cancer. In diffuse type gastric cancer, the haplotype-specific excess relative risk (ERR) for radiation was statistically significant only in the major homozygote category of IL-10 (ERR = 0.46/Gy, P = 0.037), whereas estimated ERR for radiation with the minor IL-10 homozygotes was close to 0 and nonsignificant. Thus, the minor IL-10 haplotype might act to reduce the radiation related risk of diffuse-type gastric cancer. The results suggest that this IL-10 haplotyping might be involved in development of radiation-associated gastric cancer of the diffuse type, and that IL-10 haplotypes may explain individual differences in the radiation-related risk of gastric cancer. PMID:23772925

  12. Radiative cascade of highly excited hydrogen atoms in strong magnetic fields

    SciTech Connect

    Topcu, Tuerker; Robicheaux, Francis

    2006-04-15

    We have studied the radiative decay of atomic hydrogen in strong magnetic fields of up to 4 T. We have followed the radiative cascade from completely l,m mixed distributions of highly excited states as well as from distributions that involve highly excited states with |m|{approx}n. We have found that the time it takes to populate the ground state is not affected by the magnetic field for the initial states with n < or approx. 20. For higher n manifolds, the electrons in the most negative m states are substantially slowed down by the magnetic field resulting in a much longer lifetime. We show that less than 10% of the antihydrogen atoms with n{approx}35 generated in antihydrogen experiments at 4 K will decay to their ground states before they hit the wall of the vacuum container unless they are trapped. We have also found that the decay time is mainly determined by the fraction of atoms that were initially in highest negative m states due to the fact that only {delta}m+{delta}{pi}=1 transitions are allowed in the magnetic field. We give a semiclassical method for calculating the decay rates for circular states and show that when the initial states have high-m, semiclassical rates agree with the full quantum mechanical rates within a couple of percent for states with effective n > or approx. 20.

  13. Solar radiation pressure as a mechanism of acceleration of atoms and first ions with low ionization potentials

    NASA Astrophysics Data System (ADS)

    Shestakova, L. I.

    2015-04-01

    Calculated results are presented for solar radiation pressure acting on atoms and first ions. For some of these particles, radiation pressure exceeds the gravitational attraction and can accelerate them to large velocities. A comparison of the results with ionization potentials shows that the maxima of radiation pressure on neutral atoms coincide with the minima of the first ionization potentials (FIPs). This relationship is even more apparent for first ions. The minima of the second ionization potentials (SIPs) coincide with the radiation pressure maxima for a number of ions such as Be II, Mg II, Ca II, and the neighboring elements. Thus, radiation pressure may serve as a possible mechanism of acceleration of pickup ions and energetic neutral atoms (ENA) coming from an inner source (zodiacal dust and sungrazing comets). These atoms and ions, which are not typical of the solar wind, are formed as a result of the disintegration of comets or meteor showers near the Sun and can accelerate and reach the Earth's orbit as part of the solar wind. Doubly ionized atoms have resonance lines in the UV range, where solar radiation pressure has no apparent impact on the particle dynamics; thus, the proposed acceleration mechanism can only be applied to neutral atoms and first ions with low potentials of the subsequent ionization.

  14. QED Theory of Radiation Emission and Absorption Lines for Atoms and Ions in a Strong Laser Field

    SciTech Connect

    Glushkov, A. V.

    2008-10-22

    The results of numerical calculating the multi-photon resonance shift and width for transition 6S-6F in the atom of Cs (wavelength 1059nm) in a laser pulse of the Gaussian and soliton-like shapes are presented. QED theory of radiation atomic lines is used.

  15. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors.

    PubMed

    Sasaki, Masao S; Tachibana, Akira; Takeda, Shunichi

    2014-05-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the 'integrate-and-fire' algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (i) the presence of a threshold that varied with organ, gender and age at exposure, and (ii) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to (239)Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation-environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking. PMID:24366315

  16. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors.

    PubMed

    Sasaki, Masao S; Tachibana, Akira; Takeda, Shunichi

    2014-05-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the 'integrate-and-fire' algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (i) the presence of a threshold that varied with organ, gender and age at exposure, and (ii) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to (239)Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation-environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking.

  17. Radiation-related risks of non-cancer outcomes in the atomic bomb survivors.

    PubMed

    Ozasa, K; Takahashi, I; Grant, E J

    2016-06-01

    Risks of non-cancer outcomes after exposure to atomic bomb (A-bomb) radiation have been evaluated among the Life Span Study (LSS) cohort and its subcohort, the Adult Health Study (AHS). Information regarding non-cancer outcomes in the LSS is obtained from death certificates. In the AHS, members undergo clinical examinations biennially to determine their health status. Many AHS studies have been limited to participants attending the clinic over a limited period, and therefore have varying degrees of inferential utility; as such, care is required for comparison with the LSS results. Disease structure of non-cancer diseases in Japan has changed over the long follow-up period since the end of World War II. The health status of the A-bomb survivors may be associated with the hardships of living in a devastated city and impoverished country following the prolonged war effort, in addition to the direct effects of radiation exposure. Radiation-related risk of cardiovascular disease may have increased due to radiation-related increased risk of hypertension and other secondary associations, and the risk of atherosclerotic disorders has also been reported recently. These results should be interpreted with caution because of changes in disease definitions over the follow-up period. The radiation-related risk of non-cancer respiratory diseases also appears to have increased over the follow-up period, but the shapes of the dose-response curves have shown little consistency.

  18. Radiation-related risks of non-cancer outcomes in the atomic bomb survivors.

    PubMed

    Ozasa, K; Takahashi, I; Grant, E J

    2016-06-01

    Risks of non-cancer outcomes after exposure to atomic bomb (A-bomb) radiation have been evaluated among the Life Span Study (LSS) cohort and its subcohort, the Adult Health Study (AHS). Information regarding non-cancer outcomes in the LSS is obtained from death certificates. In the AHS, members undergo clinical examinations biennially to determine their health status. Many AHS studies have been limited to participants attending the clinic over a limited period, and therefore have varying degrees of inferential utility; as such, care is required for comparison with the LSS results. Disease structure of non-cancer diseases in Japan has changed over the long follow-up period since the end of World War II. The health status of the A-bomb survivors may be associated with the hardships of living in a devastated city and impoverished country following the prolonged war effort, in addition to the direct effects of radiation exposure. Radiation-related risk of cardiovascular disease may have increased due to radiation-related increased risk of hypertension and other secondary associations, and the risk of atherosclerotic disorders has also been reported recently. These results should be interpreted with caution because of changes in disease definitions over the follow-up period. The radiation-related risk of non-cancer respiratory diseases also appears to have increased over the follow-up period, but the shapes of the dose-response curves have shown little consistency. PMID:26956675

  19. Radiation Damage from Atomic to Meso-Scales in Extreme Environments

    NASA Astrophysics Data System (ADS)

    Barnes, Cris W.; Bourke, M. A.; Malloy, S. A.; Mariam, F. G.; Merrill, F. E.; Nastasi, Michael; Pitcher, E. J.; Rej, D. J.; Sarrao, J. L.; Shlachter, J. S.

    2010-11-01

    A foreboding materials challenge is to be able to withstand the 10--15 MW-year/m^2 neutron and heat fluence expected in the first wall and blanket structural materials of a fusion reactor. Overcoming radiation damage degradation is a key rate-controlling step in fusion materials development. New science, approaches, and facilities are needed at multiple scales. The objective of the new Center for Materials at Irradiation and Mechanical Extremes is to understand, at the atomic scale, the behavior of materials subject to extreme radiation doses and mechanical stress in order to synthesize new materials that can tolerate such conditions. The Matter Radiation Interactions in Extremes (MaRIE) concept is a National User Facility to realize the vision of 21^st century materials research and development. The Fission and Fusion Materials Facility (F^3) segment of MaRIE proposes to use the present proton linac at Los Alamos with a power upgrade to drive a spallation neutron source that can provide the required radiation environment. Coupled with integrated synthesis and characterization capability, F^3 would also provide the capability for in-situ measurements of transient radiation damage, using unique x-ray and charged particle radiography diagnostics.

  20. The application of quasi-steady approximation in atomic kinetics in simulation of hohlraum radiation drive

    NASA Astrophysics Data System (ADS)

    Ren, Guoli; Pei, Wenbing; Lan, Ke; Gu, Peijun; Li, Xin; Institute of Applied Physics; Computional Mathematics Team

    2011-10-01

    In current routine 2D simulation of hohlraum physics, we adopt the principal-quantum- number(n-level) average atom model(AAM). However, the experimental frequency-dependant radiative drive differs from our n-level simulated drive, which reminds us the need of a more detailed atomic kinetics description. The orbital-quantum-number(nl-level) AAM is a natural consideration but the in-line calculation consumes much more resources. We use a new method to built up a nl-level bound electron distribution using in-line n-level calculated plasma condition (such as temperature, density, average ionization degree). We name this method ``quasi-steady approximation.'' Using the re-built nl-level bound electron distribution (Pnl) , we acquire a new hohlraum radiative drive by post-processing. Comparison with the n-level post-processed hohlraum drive shows that we get an almost identical radiation flux but with more-detailed frequency-dependant structures.

  1. Effects of laser radiation field on energies of hydrogen atom in plasmas

    SciTech Connect

    Bahar, M. K.

    2015-09-15

    In this study, for the first time, the Schrödinger equation with more general exponential cosine screened Coulomb (MGECSC) potential is solved numerically in the presence of laser radiation field within the Ehlotzky approximation using the asymptotic iteration method. The MGECSC potential includes four different potential forms in consideration of different sets of the parameters in the potential. By applying laser field, the total interaction potential of hydrogen atom embedded in plasmas converts to double well-type potential. The plasma screening effects under the influence of laser field as well as confinement effects of laser field on hydrogen atom in Debye and quantum plasmas are investigated by solving the Schrödinger equation with the laser-dressed MGECSC potential. It is resulted that since applying a monochromatic laser field on hydrogen atom embedded in a Debye and quantum plasma causes to shift in the profile of the total interaction potential, the confinement effects of laser field on hydrogen atom in plasmas modeled by the MGECSC potential change localizations of energy states.

  2. Absorption of infrared radiation by electrons in the field of a neutral hydrogen atom

    NASA Technical Reports Server (NTRS)

    Stallcop, J. R.

    1974-01-01

    An analytical expression for the absorption coefficient is developed from a relationship between the cross-section for inverse bremsstrahlung absorption and the cross-section for electron-atom momentum transfer; it is accurate for those photon frequencies v and temperatures such that hv/kT is small. The determination of the absorption of infrared radiation by free-free transitions of the negative hydrogen ion has been extended to higher temperatures. A simple analytical expression for the absorption coefficient has been derived.

  3. Photoelectron and photodissociation studies of free atoms and molecules, using synchrotron radiation

    SciTech Connect

    Medhurst, L.J.

    1991-11-01

    High resolution synchrotron radiation and Zero-Kinetic-Energy Photoelectron spectroscopy were used to study two-electron transitions in atomic systems at their ionization thresholds. Using this same technique the core-ionized mainline and satellite states of N{sub 2} and CO were studied with vibrational resolution. Vibrationally resolved synchrotron radiation was used to study the dissociation of N{sub 2}, C{sub 2}H{sub 4}, and CH{sub 3}Cl near the N 1s and C 1s thresholds. The photoelectron satellites of the argon 3s, krypton 4s and xenon 4d subshells were studied with zero kinetic energy photoelectron spectroscopy at their ionization thresholds. In all of these cases, satellites with lower binding energies are enhanced at their thresholds while those closer to the double ionization threshold are suppressed relative to their intensities at high incident light energies.

  4. Horizon in random matrix theory, the Hawking radiation, and flow of cold atoms.

    PubMed

    Franchini, Fabio; Kravtsov, Vladimir E

    2009-10-16

    We propose a Gaussian scalar field theory in a curved 2D metric with an event horizon as the low-energy effective theory for a weakly confined, invariant random matrix ensemble (RME). The presence of an event horizon naturally generates a bath of Hawking radiation, which introduces a finite temperature in the model in a nontrivial way. A similar mapping with a gravitational analogue model has been constructed for a Bose-Einstein condensate (BEC) pushed to flow at a velocity higher than its speed of sound, with Hawking radiation as sound waves propagating over the cold atoms. Our work suggests a threefold connection between a moving BEC system, black-hole physics and unconventional RMEs with possible experimental applications. PMID:19905710

  5. Horizon in Random Matrix Theory, the Hawking Radiation, and Flow of Cold Atoms

    SciTech Connect

    Franchini, Fabio; Kravtsov, Vladimir E.

    2009-10-16

    We propose a Gaussian scalar field theory in a curved 2D metric with an event horizon as the low-energy effective theory for a weakly confined, invariant random matrix ensemble (RME). The presence of an event horizon naturally generates a bath of Hawking radiation, which introduces a finite temperature in the model in a nontrivial way. A similar mapping with a gravitational analogue model has been constructed for a Bose-Einstein condensate (BEC) pushed to flow at a velocity higher than its speed of sound, with Hawking radiation as sound waves propagating over the cold atoms. Our work suggests a threefold connection between a moving BEC system, black-hole physics and unconventional RMEs with possible experimental applications.

  6. [The present state of atomic bomb survivors, with special reference to biological late-effects of radiation].

    PubMed

    Kamada, Nanao

    2004-03-01

    Atomic bombs were dropped on Hiroshima and Nagasaki in August 1945. Within a few months, the bomb blast, heat and radiation emitted by the atomic explosions led to approximately 114,000 fatalities in Hiroshima and about 70,000 in Nagasaki. The radiation in particular continued to exert effects on the human body over a long period of time, resulting in the development of tumors and functional abnormalities in various organs. This paper briefly outlines the diseases caused by radiation as well as the biological late-effects on the survivors without any specific diseases, and stresses the necessity of our enthusiastic opposition to the use of any kind of nuclear weapons.

  7. Cancer risk at low doses of ionizing radiation: artificial neural networks inference from atomic bomb survivors

    PubMed Central

    Sasaki, Masao S.; Tachibana, Akira; Takeda, Shunichi

    2014-01-01

    Cancer risk at low doses of ionizing radiation remains poorly defined because of ambiguity in the quantitative link to doses below 0.2 Sv in atomic bomb survivors in Hiroshima and Nagasaki arising from limitations in the statistical power and information available on overall radiation dose. To deal with these difficulties, a novel nonparametric statistics based on the ‘integrate-and-fire’ algorithm of artificial neural networks was developed and tested in cancer databases established by the Radiation Effects Research Foundation. The analysis revealed unique features at low doses that could not be accounted for by nominal exposure dose, including (i) the presence of a threshold that varied with organ, gender and age at exposure, and (ii) a small but significant bumping increase in cancer risk at low doses in Nagasaki that probably reflects internal exposure to 239Pu. The threshold was distinct from the canonical definition of zero effect in that it was manifested as negative excess relative risk, or suppression of background cancer rates. Such a unique tissue response at low doses of radiation exposure has been implicated in the context of the molecular basis of radiation–environment interplay in favor of recently emerging experimental evidence on DNA double-strand break repair pathway choice and its epigenetic memory by histone marking. PMID:24366315

  8. Atomic and Molecular Photoelectron and Auger Electron SpectroscopyStudies Using Synchrotron Radiation

    SciTech Connect

    Southworth, Stephen H.

    1982-01-01

    Electron spectroscopy, combined with synchrotron radiation, was used to measure the angular distributions of photoelectrons and Auger electrons from atoms and molecules as functions of photon energy. The branching ratios and partial cross sections were a 130 measured in certain cases. By comparison with theoretical calculations, the experimental results are interpreted in terms of the characteristic electronic structure and ionization dynamics of the atomic or molecular sample. The time structure of the synchrotron radiation source was used to record time-of-flight (TOF) spectra o f the ejected electrons. The ''a double-angle-TOF'' method for the measurement of photoelectron angular distributions is discussed. This technique offers the advantages of increased electron collect ion efficiency and the elimination of certain systematic errors. Several results were obtained for Xe using photon energies in the range hv {approx_equal} 60-190 eV, where excitation and ionization of the inner-subshell 4d electrons dominates. The 4d asymmetry parameter {beta} exhibits strong oscillations with energy, in agreement with several theoretical calculations. As predicted, the 5p asymmetry parameter was observed to deviate strongly from that calculated using the independent-electron model, due to intershell correlation with the 4d electrons.

  9. Genetic effects of radiation in atomic-bomb survivors and their children: past, present and future.

    PubMed

    Nakamura, Nori

    2006-01-01

    Genetic studies in the offspring of atomic bomb survivors have been conducted since 1948 at the Atomic Bomb Casualty Commission and its successor, the Radiation Effects Research Foundation, in Hiroshima and Nagasaki. Past studies include analysis of birth defects (untoward pregnancy outcome; namely, malformation, stillbirth, and perinatal death), chromosome aberrations, alterations of plasma and erythrocyte proteins as well as epidemiologic study on mortality (any cause) and cancer incidence (the latter study is still ongoing). There is, thus far, no indication of genetic effects in the offspring of survivors. Recently, the development of molecular biological techniques and human genome sequence databases made it possible to analyze DNA from parents and their offspring (trio-analysis). In addition, a clinical program is underway to establish the frequency of adult-onset multi-factorial diseases (diabetes mellitus, high blood pressure, and cardiovascular disease etc) in the offspring. The complementary kinds of data that will emerge from this three-pronged approach (clinical, epidemiologic, and molecular aspects) promise to shed light on health effects in the offspring of radiation-exposed people.

  10. Atomic physics and synchrotron radiation: The production and accumulation of highly charged ions

    NASA Astrophysics Data System (ADS)

    Johnson, B. M.; Meron, M.; Agagu, A.; Jones, K. W.

    1987-04-01

    Synchrotron radiation can be used to produce highly-charged ions, and to study photoexcitation and photoionization for ions of virtually any element in the periodic table. To date, with few exceptions, atomic physics studies have been limited to rare gases and a few metal vapors, and to photoexcitation energies in the VUV region of the electromagnetic spectrum. These limitations can now be overcome using photons produced by high-brightness synchrotron storage rings, such as the X-ray ring at the National Synchrotron Light Source (NSLS) at Brookhaven. Furthermore, calculations indicate that irradiation of an ion trap with an intense energetic photon beam will result in a viable source of highly-charged ions that can be given the name PHOBIS: the photon beam ion source. Promising results, which encourage the wider systematic use of synchrotron radiation in atomic physics research, have been obtained in recent experiments on VUV photoemission and the production and storage of multiply-charged ions. An overview of the field, current plans, and future possibilities will be presented.

  11. The International Atomic Energy Agency's activities in radiation medicine and cancer: promoting global health through diplomacy.

    PubMed

    Deatsch-Kratochvil, Amanda N; Pascual, Thomas Neil; Kesner, Adam; Rosenblatt, Eduardo; Chhem, Rethy K

    2013-02-01

    Global health has been an issue of seemingly low political importance in comparison with issues that have direct bearing on countries' national security. Recently, health has experienced a "political revolution" or a rise in political importance. Today, we face substantial global health challenges, from the spread of infectious disease, gaps in basic maternal and child health care, to the globalization of cancer. A recent estimate states that the "overall lifetime risk of developing cancer (both sexes) is expected to rise from more than one in three to one in two by 2015." These issues pose significant threats to international health security. To successfully combat these grave challenges, the international community must embrace and engage in global health diplomacy, defined by scholars Thomas Novotny and Vicanne Adams as a political activity aimed at improving global health, while at the same time maintaining and strengthening international relations. The IAEA (International Atomic Energy Agency) is an international organization with a unique mandate to "accelerate and enlarge the contribution of atomic energy to peace, health, and prosperity throughout the world." This article discusses global health diplomacy, reviews the IAEA's program activities in human health by focusing on radiation medicine and cancer, and the peaceful applications of atomic energy within the context of global health diplomacy. PMID:22560564

  12. The International Atomic Energy Agency's activities in radiation medicine and cancer: promoting global health through diplomacy.

    PubMed

    Deatsch-Kratochvil, Amanda N; Pascual, Thomas Neil; Kesner, Adam; Rosenblatt, Eduardo; Chhem, Rethy K

    2013-02-01

    Global health has been an issue of seemingly low political importance in comparison with issues that have direct bearing on countries' national security. Recently, health has experienced a "political revolution" or a rise in political importance. Today, we face substantial global health challenges, from the spread of infectious disease, gaps in basic maternal and child health care, to the globalization of cancer. A recent estimate states that the "overall lifetime risk of developing cancer (both sexes) is expected to rise from more than one in three to one in two by 2015." These issues pose significant threats to international health security. To successfully combat these grave challenges, the international community must embrace and engage in global health diplomacy, defined by scholars Thomas Novotny and Vicanne Adams as a political activity aimed at improving global health, while at the same time maintaining and strengthening international relations. The IAEA (International Atomic Energy Agency) is an international organization with a unique mandate to "accelerate and enlarge the contribution of atomic energy to peace, health, and prosperity throughout the world." This article discusses global health diplomacy, reviews the IAEA's program activities in human health by focusing on radiation medicine and cancer, and the peaceful applications of atomic energy within the context of global health diplomacy.

  13. Collision of two atoms in laser radiation field with formation of Feshbach resonances

    NASA Astrophysics Data System (ADS)

    Gazazyan, Emil A.; Gazazyan, Alfred D.; Chaltykyan, Vigen O.

    2013-09-01

    Based on the simplest two-channel model we theoretically consider laser induced elastic and inelastic collision of two atoms with formation of Feshbach resonance. In cases of one- and two-photon resonances of laser radiation with two discrete vibrational molecular levels, we show that Feshbach resonances appear at interaction of external magnetic field with dressed states formed via Autler-Townes effect. We also study the laser-induced inelastic collision and its influence on the considered processes. In case of two-photon resonance between discrete vibrational molecular states the Feshbach resonances arise under action of magnetic field via Autler-Townes effect, while the laser-induced transition into the elastic-channel continuum is in this case absent. We obtain the cross-sections of elastic and inelastic scattering and show that quenching of resonance occurs under certain conditions. The obtained results can be employed in new studies of collisions of atoms, e.g., of alkali metal atoms, and for interpretation of new experiments in BECs.

  14. Regular and Chaotic Quantum Dynamics of Two-Level Atoms in a Selfconsistent Radiation Field

    NASA Technical Reports Server (NTRS)

    Konkov, L. E.; Prants, S. V.

    1996-01-01

    Dynamics of two-level atoms interacting with their own radiation field in a single-mode high-quality resonator is considered. The dynamical system consists of two second-order differential equations, one for the atomic SU(2) dynamical-group parameter and another for the field strength. With the help of the maximal Lyapunov exponent for this set, we numerically investigate transitions from regularity to deterministic quantum chaos in such a simple model. Increasing the collective coupling constant b is identical with 8(pi)N(sub 0)(d(exp 2))/hw, we observed for initially unexcited atoms a usual sharp transition to chaos at b(sub c) approx. equal to 1. If we take the dimensionless individual Rabi frequency a = Omega/2w as a control parameter, then a sequence of order-to-chaos transitions has been observed starting with the critical value a(sub c) approx. equal to 0.25 at the same initial conditions.

  15. Updated mortality analysis of radiation workers at Rocketdyne (Atomics International), 1948-2008

    SciTech Connect

    Boice, John; Cohen, Sarah; Mumma, Michael; Ellis, Elizabeth D; Eckerman, Keith F; Leggett, Richard Wayne; Boecker, Bruce; Brill, Bertrand; Henderson, Brian

    2011-01-01

    Updated analyses of mortality data are presented on 5,801 radiation workers, including 2,232 monitored for radionuclide intakes, and 41,169 non-radiation workers employed 1948-1999 at Rocketdyne (Atomics International). The worker population is unique in that lifetime occupational doses from all places of employment were sought and incorporated into the analyses. Further, radiation doses from intakes of 14 different radionuclides were calculated for 16 organs or tissues using biokinetic models of the International Commission on Radiation Protection (ICRP). The mean dose from external radiation was 13.5 mSv (maximum 1 Sv), and the mean lung dose from external and internal radiation combined was 19.0 mSv (maximum 3.6 Sv). An additional nine years of follow-up, from December 31,1999 through 2008, increased the person-years of observation by 21.7% to 196,674 (mean 33.9 years) and the number of cancer deaths by 50% to 684. Analyses included comparisons with the general population and the computation of standardized mortality ratios (SMRs), and internal comparisons using proportional hazards models. All cancers taken together (SMR 0.88; 95% CI 0.81-0.95), lung cancer (SMR 0.87; 95% CI 0.76-1.00) and leukemia other than chronic lymphocytic leukemia (CLL) (SMR 1.04; 95% 0.67-1.53) were not significantly elevated. Cox regression analyses revealed no significant dose-response trends for any cancer. For all cancers excluding leukemia, the relative risk (RR) at 100 mSv was estimated as 0.98 (95% CI 0.82-1.17) and for all leukemia other than CLL it was 1.06 (95% CI 0.50-2.23). Uranium was the primary radionuclide contributing to internal exposures, but significant increases in lung and kidney disease were not seen. The extended follow-up re-enforces the findings in the previous study in failing to observe a detectable increase in cancer deaths associated with radiation, but strong conclusions still cannot be drawn because of small numbers and relatively low career doses. Larger

  16. Effects of Contamination, UV Radiation, and Atomic Oxygen on ISS Thermal Control Materials

    NASA Technical Reports Server (NTRS)

    Visentine, Jim; Finckenor, Miria; Zwiener, Jim; Munafo, Paul (Technical Monitor)

    2001-01-01

    Thermal control surfaces on the International Space Station (ISS) have been tailored for optimum optical properties. The space environment, particularly contamination, ultraviolet (UV) radiation, and atomic oxygen (AO) may have a detrimental effect on these optical properties. These effects must be quantified for modeling and planning. Also of interest was the effect of porosity on the reaction to simulated space environment. Five materials were chosen for this study based on their use on ISS. The thermal control materials were Z-93 white coating, silverized Teflon, chromic acid anodized aluminum, sulfuric acid anodized aluminum, and 7075-T6 aluminum. Some of the samples were exposed to RTV 560 silicone; others were exposed to Tefzel offgassing products. Two samples of Z-93 were not exposed to contamination as clean "controls". VUV radiation was used to photo-fix the contaminant to the material surface, then the samples were exposed to AO. All samples were exposed to 1000 equivalent sun-hours (ESH) of vacuum ultraviolet radiation (VUV) at the AZ Technology facility and a minimum of 1.5 x 10(exp 20) atoms/sq cm of AO at Marshall Space Flight Center. Half of the samples were exposed to an additional 2000 ESH of VUV at Huntington Beach prior to sent to AZ Technology. Darkening of the Z-93 white coating was noted after VUV exposure. AO exposure did bleach the Z-93 but not back to its original brightness. Solar absorptance curves show the degradation due to contamination and VUV and the recovery with AO exposure. More bleaching was noted on the Tefzel-contaminated samples than with the RTV-contaminated samples.

  17. Electron, Atomic, and Radiation Kinetics in Plasma Discharge Lighting: Advanced Models and Observations

    NASA Astrophysics Data System (ADS)

    Giuliani, John L.

    2006-10-01

    Non-LTE discharges used in lighting sources provide an excellent testbed for understanding the interplay between plasma, atomic, and radiation physics. Standard models for the Hg fluorescent bulb include non-equilibrium kinetics for the species, but employ both a 0-D Boltzmann equation for the electron distribution function (EDF) and Holstein's probability-of-escape for radiation transport. These assumptions overlook some of the more interesting, and challenging, aspects of plasma lighting. The radial ambipolar potential requires the inclusion of the spatial gradient term in the inhomogeneous electron Boltzmann equation. The resulting EDF is found to depend on both electron energy and radial position [1]. Advanced radiation transport techniques account for non-local photo-pumping, line overlap within the Hg resonance lines, and partial frequency redistribution [2]. The results of our completely coupled model match the observed spatial distribution of Hg excited states and the line-of-sight intensity [3]. Due to environmental initiatives there is also recent interest in non-Hg discharges for high intensity lighting. One example is an RF electrodeless Mo-O-Ar plasma discharge bulb which operates by recycling the emitting Mo with an O catalyst. Based on atomic physics calculations for Mo [4], the kinetic pathways leading to visible emission can be identified [5] and explain the measured lighting efficiency of ˜40 lumens/watt of supplied power.[1] J. Appl. Phys., 94, p.62, 2003. [2] Plasma Sources Sci. Tech., 14, p.236, 2005. [3] J. Phys. D., 38, p.4180, 2005. [4] New J. Physics, 6, p.145, 2004. [5] J. Appl. Phys., 95, p.5284, 2004.

  18. Effect of radiation on age at menopause among atomic bomb survivors.

    PubMed

    Sakata, Ritsu; Shimizu, Yukiko; Soda, Midori; Yamada, Michiko; Hsu, Wan-Ling; Hayashi, Mikiko; Ozasa, Kotaro

    2011-12-01

    Exposure to ionizing radiation has been thought to induce ovarian failure and premature menopause. Proximally exposed female atomic bomb survivors were reported to experience menopause immediately after the exposure more often than those who were distally exposed. However, it remains unclear whether such effects were caused by physical injury and psychological trauma or by direct effects of radiation on the ovaries. The objective of this study was to see if there are any late health effects associated with the exposure to atomic bomb radiation in terms of age at menopause in a cohort of 21,259 Life Span Study female A-bomb survivors. Excess absolute rates (EAR) of natural and artificial menopause were estimated using Poisson regression. A linear threshold model with a knot at 0.40 Gy [95% confidence interval (CI): 0.13, 0.62] was the best fit for a dose response of natural menopause (EAR at 1 Gy at age of 50 years = 19.4/1,000 person-years, 95% CI: 10.4, 30.8) and a linear threshold model with a knot at 0.22 Gy (95% CI: 0.14, 0.34) was the best fit for artificial menopause (EAR at 1 Gy at age of 50 years for females who were exposed at age of 20 years = 14.5/1,000 person-years, 95% CI: 10.2, 20.1). Effect modification by attained age indicated that EARs peaked around 50 years of age for both natural and artificial menopause. Although effect modification by age at exposure was not significant for natural menopause, the EAR for artificial menopause tended to be larger in females exposed at young ages. On the cumulative incidence curve of natural menopause, the median age at menopause was 0.3 years younger in females exposed to radiation of 1 Gy compared with unexposed females. The median age was 1 year younger for combined natural and artificial menopause in the same comparison. In conclusion, age at menopause was thought to decrease with increasing radiation dose for both natural and artificial menopause occurring at least 5 years after the exposure.

  19. Effect of radiation on age at menopause among atomic bomb survivors.

    PubMed

    Sakata, Ritsu; Shimizu, Yukiko; Soda, Midori; Yamada, Michiko; Hsu, Wan-Ling; Hayashi, Mikiko; Ozasa, Kotaro

    2011-12-01

    Exposure to ionizing radiation has been thought to induce ovarian failure and premature menopause. Proximally exposed female atomic bomb survivors were reported to experience menopause immediately after the exposure more often than those who were distally exposed. However, it remains unclear whether such effects were caused by physical injury and psychological trauma or by direct effects of radiation on the ovaries. The objective of this study was to see if there are any late health effects associated with the exposure to atomic bomb radiation in terms of age at menopause in a cohort of 21,259 Life Span Study female A-bomb survivors. Excess absolute rates (EAR) of natural and artificial menopause were estimated using Poisson regression. A linear threshold model with a knot at 0.40 Gy [95% confidence interval (CI): 0.13, 0.62] was the best fit for a dose response of natural menopause (EAR at 1 Gy at age of 50 years = 19.4/1,000 person-years, 95% CI: 10.4, 30.8) and a linear threshold model with a knot at 0.22 Gy (95% CI: 0.14, 0.34) was the best fit for artificial menopause (EAR at 1 Gy at age of 50 years for females who were exposed at age of 20 years = 14.5/1,000 person-years, 95% CI: 10.2, 20.1). Effect modification by attained age indicated that EARs peaked around 50 years of age for both natural and artificial menopause. Although effect modification by age at exposure was not significant for natural menopause, the EAR for artificial menopause tended to be larger in females exposed at young ages. On the cumulative incidence curve of natural menopause, the median age at menopause was 0.3 years younger in females exposed to radiation of 1 Gy compared with unexposed females. The median age was 1 year younger for combined natural and artificial menopause in the same comparison. In conclusion, age at menopause was thought to decrease with increasing radiation dose for both natural and artificial menopause occurring at least 5 years after the exposure. PMID:21988524

  20. Atomic Bomb Survivors Life-Span Study: Insufficient Statistical Power to Select Radiation Carcinogenesis Model.

    PubMed

    Socol, Yehoshua; Dobrzyński, Ludwik

    2015-01-01

    The atomic bomb survivors life-span study (LSS) is often claimed to support the linear no-threshold hypothesis (LNTH) of radiation carcinogenesis. This paper shows that this claim is baseless. The LSS data are equally or better described by an s-shaped dependence on radiation exposure with a threshold of about 0.3 Sievert (Sv) and saturation level at about 1.5 Sv. A Monte-Carlo simulation of possible LSS outcomes demonstrates that, given the weak statistical power, LSS cannot provide support for LNTH. Even if the LNTH is used at low dose and dose rates, its estimation of excess cancer mortality should be communicated as 2.5% per Sv, i.e., an increase of cancer mortality from about 20% spontaneous mortality to about 22.5% per Sv, which is about half of the usually cited value. The impact of the "neutron discrepancy problem" - the apparent difference between the calculated and measured values of neutron flux in Hiroshima - was studied and found to be marginal. Major revision of the radiation risk assessment paradigm is required.

  1. Atomic Bomb Survivors Life-Span Study: Insufficient Statistical Power to Select Radiation Carcinogenesis Model.

    PubMed

    Socol, Yehoshua; Dobrzyński, Ludwik

    2015-01-01

    The atomic bomb survivors life-span study (LSS) is often claimed to support the linear no-threshold hypothesis (LNTH) of radiation carcinogenesis. This paper shows that this claim is baseless. The LSS data are equally or better described by an s-shaped dependence on radiation exposure with a threshold of about 0.3 Sievert (Sv) and saturation level at about 1.5 Sv. A Monte-Carlo simulation of possible LSS outcomes demonstrates that, given the weak statistical power, LSS cannot provide support for LNTH. Even if the LNTH is used at low dose and dose rates, its estimation of excess cancer mortality should be communicated as 2.5% per Sv, i.e., an increase of cancer mortality from about 20% spontaneous mortality to about 22.5% per Sv, which is about half of the usually cited value. The impact of the "neutron discrepancy problem" - the apparent difference between the calculated and measured values of neutron flux in Hiroshima - was studied and found to be marginal. Major revision of the radiation risk assessment paradigm is required. PMID:26673526

  2. The pristine atomic structure of MoS2 monolayer protected from electron radiation damage by graphene

    NASA Astrophysics Data System (ADS)

    Algara-Siller, Gerardo; Kurasch, Simon; Sedighi, Mona; Lehtinen, Ossi; Kaiser, Ute

    2013-11-01

    Materials can, in principle, be imaged at the level of individual atoms with aberration-corrected transmission electron microscopy. However, such resolution can be attained only with very high electron doses. Consequently, radiation damage is often the limiting factor when characterizing sensitive materials. Here, we demonstrate a simple and an effective method to increase the electron radiation tolerance of materials by using graphene as protective coating. This leads to an improvement of three orders of magnitude in the radiation tolerance of monolayer MoS2. Further on, we construct samples in different heterostructure configurations to separate the contributions of different radiation damage mechanisms.

  3. The Cold War legacy of regulatory risk analysis: The Atomic Energy Commission and radiation safety

    NASA Astrophysics Data System (ADS)

    Boland, Joseph B.

    From its inception in 1946 the Atomic Energy Commission pioneered the use of risk analysis as a mode of regulatory rationality and political rhetoric, yet historical treatments of risk analysis nearly always overlook the important role it played in the administration of atomic energy during the early Cold War. How this absence from history has been achieved and why it characterizes most historical accounts are the subjects of Chapter II. From there, this study goes on to develop the thesis that the advent of the atomic bomb was a world-shattering event that forced the Truman administration to choose between two novel alternatives: (1) movement towards global governance based initially on cooperative control of atomic energy or (2) unsparing pursuit of nuclear superiority. I refer to these as nuclear internationalism and nuclear nationalism, respectively. Each defined a social risk hierarchy. With the triumph of nuclear nationalism, nuclear annihilation was designated the greatest risk and a strong nuclear defense the primary means of prevention. The AEC's mission in the 1950s consisted of the rapid development of a nuclear arsenal, continual improvements in weapons technologies, and the promotion of nuclear power. The agency developed a risk-based regulatory framework through its dominant position within the National Committee on Radiation Protection. It embraced a technocratic model of risk analysis whose articulation and application it controlled, largely in secret. It used this to undergird a public rhetoric of reassurance and risk minimization. In practice, safety officials adjusted exposure levels within often wide parameters and with considerable fluidity in order to prevent safety concerns from interfering with operations. Secrecy, the political climate of the time, and a lack of accountability enabled the agency to meld technical assessments with social value judgments in a manner reflective of nuclear nationalism's risk hierarchy. In the late fifties

  4. Updated Mortality Analysis of Radiation Workers at Rocketdyne (Atomics International), 1948-2008

    SciTech Connect

    Boice Jr JD, Colen SS, Mumma MT, Ellis ED, Eckerman DF, Leggett RW, Boecker BB, Brill B, Henderson BE

    2011-08-01

    Updated analyses of mortality data are presented on 46,970 workers employed 1948-1999 at Rocketdyne (Atomics International). Overall, 5,801 workers were involved in radiation activities, including 2,232 who were monitored for intakes of radionuclides, and 41,169 workers were engaged in rocket testing or other non-radiation activities. The worker population is unique in that lifetime occupational doses from all places of employment were sought, updated and incorporated into the analyses. Further, radiation doses from intakes of 14 different radionuclides were calculated for 16 organs or tissues using biokinetic models of the International Commission on Radiation Protection (ICRP). Because only negligible exposures were received by the 247 workers monitored for radiation activities after 1999, the mean dose from external radiation remained essentially the same at 13.5 mSv (maximum 1 Sv) as reported previously, as did the mean lung dose from external and internal radiation combined at 19.0 mSv (maximum 3.6 Sv). An additional 9 years of follow-up, from December 31,1999 through 2008, increased the person-years of observation for the radiation workers by 21.7% to 196,674 (mean 33.9 years) and the number of cancer deaths by 50% to 684. Analyses included external comparisons with the general population and the computation of standardized mortality ratios (SMRs) and internal comparisons using proportional hazards models and the computation of relative risks (RRs). A low SMR for all causes of death (SMR 0.82; 95% CI 0.78-0.85) continued to indicate that the Rocketdyne radiation workers were healthier than the general population and were less likely to die. The SMRs for all cancers taken together (SMR 0.88; 95% CI 0.81-0.95), lung cancer (SMR 0.87; 95% CI 0.76-1.00) and leukemia other than chronic lymphocytic leukemia (CLL) (SMR 1.04; 95% 0.67-1.53) were not significantly elevated. Cox regression analyses revealed no significant dose-response trends for any cancer. For all

  5. A technique for synergistic atomic oxygen and vacuum ultraviolet radiation durability evaluation of materials for use in LEO

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Banks, Bruce A.

    1996-01-01

    Material erosion data collected during flight experiments such as the Environmental Oxygen Interaction with Materials (EOIM)-3 and the Long Duration Exposure Facility (LDEF) have raised questions as to the sensitivity of material erosion to levels of atomic oxygen exposure and vacuum ultraviolet (VUV) radiation. The erosion sensitivity of some materials such as FEP Teflon used as a thermal control material on satellites in low Earth orbit (LEO), is particularly important but difficult to determine. This is in large part due to the inability to hold all but one exposure parameter constant during a flight experiment. This is also difficult to perform in a ground based facility, because often the variation of the level of atomic oxygen or VUV radiation also results in a change in the level of the other parameter. A facility has been developed which allows each parameter to be changed almost independently and offer broad area exposure. The resulting samples can be made large enough for mechanical testing. The facility uses an electron cyclotron resonance plasma source to provide the atomic oxygen. A series of glass plates is used to focus the atomic oxygen while filtering the VUV radiation from the plasma source. After filtering, atomic oxygen effective flux levels can still be measured which are as high as 7 x 10(exp 15) atoms/cm(exp 2)-sec which is adequate for accelerated testing. VUV radiation levels after filtering can be as low as 0.3 suns. Additional VUV suns can be added with the use of deuterium lamps which allow the VUV level to be changed while keeping the flux of atomic oxygen constant. This paper discusses the facility, and results from exposure of Kapton and FEP at pre-determined atomic oxygen flux and VUV sun levels.

  6. Collisional and Radiative Processes in Adiabatic Deceleration, Deflection, and Off-Axis Trapping of a Rydberg Atom Beam

    SciTech Connect

    Seiler, Ch.; Hogan, S. D.; Schmutz, H.; Agner, J. A.; Merkt, F.

    2011-02-18

    A supersonic beam of Rydberg hydrogen atoms has been adiabatically deflected by 90 deg., decelerated to zero velocity in less than 25 {mu}s, and loaded into an electric trap. The deflection has allowed the suppression of collisions with atoms in the trailing part of the gas pulse. The processes leading to trap losses, i.e., fluorescence to the ground state, and transitions and ionization induced by blackbody radiation have been monitored over several milliseconds and quantitatively analyzed.

  7. In Vacuo Photoemission Studies of Platinum Atomic Layer Deposition Using Synchrotron Radiation.

    PubMed

    Geyer, Scott M; Methaapanon, Rungthiwa; Shong, Bonggeun; Pianetta, Piero A; Bent, Stacey F

    2013-01-01

    The mechanism of platinum atomic layer deposition using (methylcyclopentadienyl)trimethylplatinum and oxygen is investigated with in vacuo photoemission spectroscopy at the Stanford Synchrotron Radiation Lightsource. With this surface-sensitive technique, the surface species following the Pt precursor half cycle and the oxygen counter-reactant half cycle can be directly measured. We observed significant amounts of carbonaceous species following the Pt precursor pulse, consistent with dehydrogenation of the precursor ligands. Significantly more carbon is observed when deposition is carried out in the thermal decomposition temperature region. The carbonaceous layer is removed during the oxygen counter reactant pulse, and the photoemission spectrum shows that a layer of adsorbed oxygen remains on the surface as previously predicted. PMID:26291229

  8. Vacuum ultraviolet radiation and thermal cycling effects on atomic oxygen protective photovoltaic array blanket materials

    NASA Technical Reports Server (NTRS)

    Brady, J.; Banks, B.

    1990-01-01

    The importance of synergistic environmental exposure is demonstrated through the evaluation of DuPont 93-1 in simulated LEO environment. Changes in optical properties, surface condition, and mass loss data are described. The qualitative results indicate the necessity for exposure of materials to a series of simulated LEO environments in order to properly determine synergistic effects and demonstrate the overall LEO durability of candidate materials. It is shown that synergistic effects may occur with vacuum thermal cycling combined with VUV radiation followed by atomic oxygen exposure. Testing the durability of candidate solar array blanket materials in a test sequence with necessary synergistic effects makes it possible to determine the appropriate material for providing structural support and maintaining the proper operating temperature for solar cells in the SSF Photovaltaic Power System.

  9. Effect of radiation dose on the height of atomic bomb survivors: a longitudinal study.

    PubMed

    Nakashima, Eiji; Fujiwara, Saeko; Funamoto, Sachiyo

    2002-09-01

    We conducted a longitudinal analysis of height after age 20 for atomic bomb survivors in the Adult Health Study (AHS) cohort. The measurements we used were made from July 1958 to June 1998 (AHS examination cycles 1-20). We analyzed only the subjects with known atomic bomb radiation doses, excluding those who were not in the city at the time of bombing (ATB) and those exposed in utero. We also excluded from the analysis measurements made after the occurrence of vertebral fracture. The total number of subjects was 11,862, and the total number of measurements was 109,770; the mean number of measurements per subject was 9.25. Assuming that stature after age 20 is approximately constant, a simple mixed-effects model was fitted to stature after age 20, and linear dose effects for young ATB subjects were modeled for both sexes. The estimated mean heights for subjects born in 1945 in Hiroshima were 166.0 cm for men and 155.4 cm for women. The sex difference in height was 10.6 cm, with men significantly taller than women (P < 0.001). The difference between the cities was not significant (P = 0.162). The birth cohort effects per decade were -1.7 cm for men (P < 0.001) and -2.1 cm for women (P < 0.001). A reduction of stature due to radiation exposure was observed for individuals of both sexes who were below 19 years of age ATB (95% confidence interval, 17-21 years), and the dose effect was larger for women than for men (P = 0.028). The estimated effects per gray for those who were age 0 ATB were -1.2 cm for men and -2.0 cm for women and for those who were age 10 ATB were-0.57 cm for men and -0.96 cm for women.

  10. Association of Acute Radiation Syndrome and Rain after the Bombings in Atomic Bomb Survivors.

    PubMed

    Ozasa, K; Sakata, R; Cullings, H M; Grant, E J

    2016-06-01

    Acute radiation-induced symptoms reported in survivors after the atomic bombings in Hiroshima and Nagasaki have been suspected to be associated with rain that fell after the explosions, but this association has not been evaluated in an epidemiological study that considers the effects of the direct dose from the atomic bombs and other factors. The aim of this study was to evaluate this association using information from a fixed cohort, comprised of 93,741 members of the Life Span Study who were in the city at the time of the bombing. Information on acute symptoms and exposure to rain was collected in surveys conducted by interviewers, primarily in the 1950s. The proportion of survivors developing severe epilation was around 60% at levels of direct radiation doses of 3 Gy or higher and less than 0.2% at levels <0.005 Gy regardless of reported rain exposure status. The low prevalence of acute symptoms at low direct doses indicates that the reported fallout rain was not homogeneously radioactive at a level sufficient to cause a substantial probability of acute symptoms. We observed that the proportion of reported acute symptoms was slightly higher among those who reported rain exposure in some subgroups, however, suggestions that rain was the cause of these reported symptoms are not supported by analyses specific to the known areas of radioactive fallout. Misclassification of exposure and outcome, including symptoms due to other causes and recall bias, appears to be a more plausible explanation. However, the insufficient and retrospective nature of the available data limited our ability to quantify the attribution to those possible causes.

  11. Association of Acute Radiation Syndrome and Rain after the Bombings in Atomic Bomb Survivors.

    PubMed

    Ozasa, K; Sakata, R; Cullings, H M; Grant, E J

    2016-06-01

    Acute radiation-induced symptoms reported in survivors after the atomic bombings in Hiroshima and Nagasaki have been suspected to be associated with rain that fell after the explosions, but this association has not been evaluated in an epidemiological study that considers the effects of the direct dose from the atomic bombs and other factors. The aim of this study was to evaluate this association using information from a fixed cohort, comprised of 93,741 members of the Life Span Study who were in the city at the time of the bombing. Information on acute symptoms and exposure to rain was collected in surveys conducted by interviewers, primarily in the 1950s. The proportion of survivors developing severe epilation was around 60% at levels of direct radiation doses of 3 Gy or higher and less than 0.2% at levels <0.005 Gy regardless of reported rain exposure status. The low prevalence of acute symptoms at low direct doses indicates that the reported fallout rain was not homogeneously radioactive at a level sufficient to cause a substantial probability of acute symptoms. We observed that the proportion of reported acute symptoms was slightly higher among those who reported rain exposure in some subgroups, however, suggestions that rain was the cause of these reported symptoms are not supported by analyses specific to the known areas of radioactive fallout. Misclassification of exposure and outcome, including symptoms due to other causes and recall bias, appears to be a more plausible explanation. However, the insufficient and retrospective nature of the available data limited our ability to quantify the attribution to those possible causes. PMID:27223827

  12. Implementation of dose management system at radiation protection board of Ghana Atomic Energy Commission.

    PubMed

    Hasford, F; Amoako, J K; Darko, E O; Emi-Reynolds, G; Sosu, E K; Otoo, F; Asiedu, G O

    2012-01-01

    The dose management system (DMS) is a computer software developed by the International Atomic Energy Agency for managing data on occupational exposure to radiation sources and intake of radionuclides. It is an integrated system for the user-friendly storage, processing and control of all existing internal and external dosimetry data. The Radiation Protection Board (RPB) of the Ghana Atomic Energy Commission has installed, customised, tested and using the DMS as a comprehensive DMS to improve personnel and area monitoring in the country. Personnel dose records from the RPBs database from 2000 to 2009 are grouped into medical, industrial and education/research sectors. The medical sector dominated the list of monitored institutions in the country over the 10-y period representing ∼87 %, while the industrial and education/research sectors represent ∼9 and ∼4 %, respectively. The number of monitored personnel in the same period follows a similar trend with medical, industrial and education/research sectors representing ∼74, ∼17 and ∼9 %, respectively. Analysis of dose data for 2009 showed that there was no instance of a dose above the annual dose limit of 20 mSv, however, 2.7 % of the exposed workers received individual annual doses >1 mSv. The highest recorded individual annual dose and total collective dose in all sectors were 4.73 mSv and 159.84 man Sv, respectively. Workers in the medical sector received higher individual doses than in the other two sectors, and average dose per exposed worker in all sectors is 0.25 mSv.

  13. Estimation of radiation doses for atomic-bomb survivors in the Hiroshima University Registry

    SciTech Connect

    Hoshi, M.; Matsuura, M.; Hayakawa, N.; Kamada, N.; Ito, C.

    1996-05-01

    The present study presents the Hiroshima University Registry of atomic bomb survivors, of which the total number is about 270,000, and application of absorbed doses. From this registry, we picked up 49,102 survivors and applied organ doses based on the dosimetry system 1986 (DS86), which is named the Atomic Bomb Survivor 1993 Dose (ABS93D). The applied dose data are based on the tables listed in the DS86 final report such as the free-in-air kermas, the house shielding factors, and organ dose factors for the active bone marrow and the breast. Calculations for the 13 other organs provided in DS86 are possible. To obtained the organ doses for each survivor, it is necessary to obtain information concerning (1) place exposed, (2) whether they were shielded or not, and (3) age. ABS93D body transmission factors for active bone marrow for neutrons and gamma rays agreed with DS 86 to within a few percent. Of the survivors studied, 35, 123 of them were used for the relative risk estimation of leukemia mortality, adopting the same method as the Radiation Effects Research Foundation (RERF) for comparison. For the observation period from 1968 to 1989, the analyzed relative risks for leukemia mortality at 1 Gy by shielded kerm and by active bone marrow dose are 2.01 and 2.37, respectively, which are consistent with the RERF results. 11 refs., 1 fig., 3 tabs.

  14. Reassessment of atomic bomb radiation dosimetry in Hiroshima and Nagasaki: proceedings

    SciTech Connect

    Not Available

    1983-06-01

    The presentations at this workshop are the first of a series of joint efforts, among knowledgeable scientists in Japan and the United States under RERF auspices, directed toward reassessing the dose of ionizing radiation received by survivors of the atomic bombs dropped on Hiroshima and Nagasaki. The last previous dose estimate revisions occurred in 1965 and since that time new technology and understanding have become available for this purpose. It is the hope of RERF that the collaboration represented by this workshop and the following day of free discussion among the participating scientists will establish a procedure which will ensure that the resulting dose estimates are as accurate as possible. Acceptance of the resulting estimates by the scientific communities of both nations is our ultimate goal. This first workshop has concentrated on presenting current evidence concerning the yield of the two weapons, the spectra of the radiations from them, their transport through air, and various in situ measurements of the resulting excitation of materials on the ground (insulators, roof tiles, iron rods, etc.) which can be used to check the theoretical calculations.

  15. Dosimetry for occupational exposure to cosmic radiation.

    PubMed

    Bartlett, D T; McAulay, I R; Schrewe, U J; Schnuer, K; Menzel, H G; Bottollier-Depois, J F; Dietze, G; Gmur, K; Grillmaeir, R E; Heinrich, W; Lim, T; Lindborg, L; Reitz, G; Schraube, H; Spurny, F; Tommasino, L

    1997-01-01

    In the course of their work, aircraft crew and frequent flyers are exposed to elevated levels of cosmic radiation of galactic and solar origin and secondary radiation produced in the atmosphere, aircraft structure, etc. This has been recognised for some time and estimates of the exposure of aircraft crew have been made previously and included in, for example, UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) publications. The recent increased interest has been brought about by several factors--the consideration that the relative biological effectiveness of the neutron component as being underestimated; the trend towards higher cruising altitudes for subsonic commercial aircraft and business jet aircraft; and, most importantly, the recommendations of the International Commission on Radiological Protection (ICRP) in Publication 60, and the revision of the Euratom Basic Safety Standards Directive (BSS). In 1992, the European Dosimetry Group (EURADOS) established a Working Group to consider the exposure to cosmic radiation of aircraft crew, and the scientific and technical problems associated with radiation protection dosimetry for this occupational group. The Working Group was composed of fifteen scientists (plus a corresponding member) involved in this field of study and with knowledge of radiation measurement at aviation altitudes. This paper is based on the findings of this Working Group. Where arrangements are made to take account of the exposure of aircraft crew to cosmic radiation, dose estimation procedures will not be necessary for persons for whom total annual doses are not liable to exceed 1 mSv, and therefore, in general, for crew on aircraft not routinely flying above 8 km. Where estimates of effective dose and, in the case of female staff who are pregnant, equivalent dose to the embryo or fetus, are required (for regulatory or other purposes), it was concluded that the preferred procedure was to determine route doses and

  16. Atomic Scale Mechanisms of Radiation Effects in Si-SiO2 Systems

    NASA Astrophysics Data System (ADS)

    Rashkeev, Sergey N.

    2002-03-01

    It is generally accepted that interface-trap formation in Si-SiO2 systems is the result of radiation-released protons. Three different types of behavior have been observed for H in Si-SiO2 structures: a) Radiation experiments established that H^+ released in SiO2 migrates to the Si-SiO2 interface where it induces new defects; b) For oxides exposed first to high-temperature annealing and then to molecular hydrogen, mobile positive charge believed to be H^+ can be cycled to and from the interface by reversing the oxide electric field; c) Hydrogen is known to passivate Si dangling bonds at the Si-SiO2 interface, but the subsequent arrival of H^+ at the interface causes depassivation of Si-H bonds. We report first-principles calculations that identify atomic-scale mechanisms for the different types of behavior and the conditions that are necessary for each. We show that Si-Si bonds on the oxide side, i.e., ``suboxide bonds'', can trap H^+ in deep wells with asymmetric barrier. In radiation experiments these centers can act as fixed positive charge. In the mobile-positive-charge experiments, the protons can be cycled between opposite Si-SiO2 interfaces if the density of suboxide bonds is high. Also, we establish that H^+ is the only stable charge state at the interface and that H^+ reacts directly (without being neutralized by a Si electron) with a Si-H bond, forming an H2 molecule and a positively charged dangling bond (Pb center). As a result, H-induced interface-trap formation does not depend on the availability of Si electrons. This work was supported in part by AFOSR Grant F-49620-99-1-0289, and done in collaboration with S. T. Pantelides, D. M. Fleetwood, and R. D. Schrimpf.

  17. Vacuum Ultraviolet Radiation and Atomic Oxygen Durability Evaluation of HST Bi-Stem Thermal Shield Materials

    NASA Technical Reports Server (NTRS)

    Dever, Joyce; deGroh, Kim K.

    2002-01-01

    Bellows-type thermal shields were used on the bi-stems of replacement solar arrays installed on the Hubble Space Telescope (HST) during the first HST servicing mission (SMI) in December 1993. These thermal shields helped reduce the problem of thermal gradient- induced jitter observed with the original HST solar arrays during orbital thermal cycling and have been in use on HST for eight years. This paper describes ground testing of the candidate solar array bi-stem thermal shield materials including backside aluminized Teflon(R)FEP (fluorinated ethylene propylene) with and without atomic oxygen (AO) and ultraviolet radiation protective surface coatings for durability to AO and combined AO and vacuum ultraviolet (VOV) radiation. NASA Glenn Research Center (GRC) conducted VUV and AO exposures of samples of candidate thermal shield materials at HST operational temperatures and pre- and post-exposure analyses as part of an overall program coordinated by NASA Goddard Space Flight Center (GSFC) to determine the on-orbit durability of these materials. Coating adhesion problems were observed for samples having the AO- and combined AO/UV-protective coatings. Coating lamination occurred with rapid thermal cycling testing which simulated orbital thermal cycling. This lack of adhesion caused production of coating flakes from the material that would have posed a serious risk to HST optics if the coated materials were used for the bi-stem thermal shields. No serious degradation was observed for the uncoated aluminized Teflon(R) as evaluated by optical microscopy, although atomic force microscopy (AFM) microhardness testing revealed that an embrittled surface layer formed on the uncoated Teflon(R) surface due to vacuum ultraviolet radiation exposure. This embrittled layer was not completely removed by AO erosion, No cracks or particle flakes were produced for the embrittled uncoated material upon exposure to VUV and AO at operational temperatures to an equivalent exposure of

  18. Ab initio calculations of atomic coherence excited by optical pulses: CEP effects and generation of X-ray radiation

    NASA Astrophysics Data System (ADS)

    Dhayal, Suman; Rostovtsev, Yuri

    2011-03-01

    Recent progress in ultrashort, e.g. attosecond, laser technology allows to obtain ultra-strong fields which can be of the same order of magnitude as the electric field created by an atomic nucleus. Interaction of such strong and broadband field with atomic systems even under the action of a far-off resonance strong pulse of laser radiation should be revisited. As we have shown, such pulses can excite remarkable coherence on high frequency transitions. We have found and analyzed analitical solutions for various pulse shapes. We have developed new mechanisms of efficient atomic coherent excitation by using two-frequency laser pulses and via tunneling through electric fields. We have done ab initio calculations using TDDFT for several atoms and simple molecules interacting with strong optical fields. We compare efficiency generation with the efficiency of high harmonic generation approach, and discuss the CEP effects and possible applications of the results obtained to cooperative generation of XUV radiation. The efficiency of XUV generation is calculated for particular candidates for XUV radiation such as H (100 nm) and He (50 nm) atoms and H-like ions (Li 2+ (30 nm), as well as Ar 8+ and Xe 8+ (30-50 nm).

  19. Identifying Student and Teacher Difficulties in Interpreting Atomic Spectra Using a Quantum Model of Emission and Absorption of Radiation

    ERIC Educational Resources Information Center

    Savall-Alemany, Francisco; Domènech-Blanco, Josep Lluís; Guisasola, Jenaro; Martínez-Torregrosa, Joaquín

    2016-01-01

    Our study sets out to identify the difficulties that high school students, teachers, and university students encounter when trying to explain atomic spectra. To do so, we identify the key concepts that any quantum model for the emission and absorption of electromagnetic radiation must include to account for the gas spectra and we then design two…

  20. Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

    NASA Astrophysics Data System (ADS)

    Seiler, Ch; Agner, J. A.; Pillet, P.; Merkt, F.

    2016-05-01

    Supersonic beams of hydrogen atoms, prepared selectively in Rydberg-Stark states of principal quantum number n in the range between 25 and 35, have been deflected by {90}\\circ , decelerated and loaded into off-axis electric traps at initial densities of ≈ {10}6 atoms cm-3 and translational temperatures of 150 mK. The ability to confine the atoms spatially was exploited to study their decay by radiative and collisional processes. The evolution of the population of trapped atoms was measured for several milliseconds in dependence of the principal quantum number of the initially prepared states, the initial Rydberg-atom density in the trap, and the temperature of the environment of the trap, which could be varied between 7.5 and 300 K using a cryorefrigerator. At room temperature, the population of trapped Rydberg atoms was found to decay faster than expected on the basis of their natural lifetimes, primarily because of absorption and emission stimulated by the thermal radiation field. At the lowest temperatures investigated experimentally, the decay was found to be multiexponential, with an initial rate scaling as {n}-4 and corresponding closely to the natural lifetimes of the initially prepared Rydberg-Stark states. The decay rate was found to continually decrease over time and to reach an almost n-independent rate of more than (1 ms)-1 after 3 ms. To analyze the experimentally observed decay of the populations of trapped atoms, numerical simulations were performed which included all radiative processes, i.e., spontaneous emission as well as absorption and emission stimulated by the thermal radiation. These simulations, however, systematically underestimated the population of trapped atoms observed after several milliseconds by almost two orders of magnitude, although they reliably predicted the decay rates of the remaining atoms in the trap. The calculations revealed that the atoms that remain in the trap for the longest times have larger absolute values of the

  1. PHYSICAL BASIS OF QUANTUM ELECTRONICS: Frequency shift of radiation of an atom near a cluster of two perfectly conducting spherical nanoparticles

    NASA Astrophysics Data System (ADS)

    Guzatov, D. V.

    2005-10-01

    Expressions for the frequency shift of radiation of an atom located near a cluster of two perfectly conducting spherical nanoparticles are obtained within the framework of a classical model. The asymptotic expression is found for the radiation frequency shift of an atom located between spheres approaching each other.

  2. Radiation risks in lung cancer screening programs: a comparison with nuclear industry workers and atomic bomb survivors.

    PubMed

    McCunney, Robert J; Li, Jessica

    2014-03-01

    The National Lung Cancer Screening Trial (NLST) demonstrated that screening with low-dose CT (LDCT) scan reduced lung cancer and overall mortality by 20% and 7%, respectively. The LDCT scanning involves an approximate 2-mSv dose, whereas full-chest CT scanning, the major diagnostic study used to follow up nodules, may involve a dose of 8 mSv. Radiation associated with CT scanning and other diagnostic studies to follow up nodules may present an independent risk of lung cancer. On the basis of the NLST, we estimated the incidence and prevalence of nodules detected in screening programs. We followed the Fleischner guidelines for follow-up of nodules to assess cumulative radiation exposure over 20- and 30-year periods. We then evaluated nuclear worker cohort studies and atomic bomb survivor studies to assess the risk of lung cancer from radiation associated with long-term lung cancer screening programs. The findings indicate that a 55-year-old lung screening participant may experience a cumulative radiation exposure of up to 280 mSv over a 20-year period and 420 mSv over 30 years. These exposures exceed those of nuclear workers and atomic bomb survivors. This assessment suggests that long-term (20-30 years) LDCT screening programs are associated with nontrivial cumulative radiation doses. Current lung cancer screening protocols, if conducted over 20- to 30-year periods, can independently increase the risk of lung cancer beyond cigarette smoking as a result of cumulative radiation exposure. Radiation exposures from LDCT screening and follow-up diagnostic procedures exceed lifetime radiation exposures among nuclear power workers and atomic bomb survivors.

  3. RET/PTC rearrangements preferentially occurred in papillary thyroid cancer among atomic bomb survivors exposed to high radiation dose.

    PubMed

    Hamatani, Kiyohiro; Eguchi, Hidetaka; Ito, Reiko; Mukai, Mayumi; Takahashi, Keiko; Taga, Masataka; Imai, Kazue; Cologne, John; Soda, Midori; Arihiro, Koji; Fujihara, Megumu; Abe, Kuniko; Hayashi, Tomayoshi; Nakashima, Masahiro; Sekine, Ichiro; Yasui, Wataru; Hayashi, Yuzo; Nakachi, Kei

    2008-09-01

    A major early event in papillary thyroid carcinogenesis is constitutive activation of the mitogen-activated protein kinase signaling pathway caused by alterations of a single gene, typically rearrangements of the RET and NTRK1 genes or point mutations in the BRAF and RAS genes. In childhood papillary thyroid cancer, regardless of history of radiation exposure, RET/PTC rearrangements are a major event. Conversely, in adult-onset papillary thyroid cancer among the general population, the most common molecular event is BRAF(V600E) point mutation, not RET/PTC rearrangements. To clarify which gene alteration, chromosome aberration, or point mutation preferentially occurs in radiation-associated adult-onset papillary thyroid cancer, we have performed molecular analyses on RET/PTC rearrangements and BRAF(V600E) mutation in 71 papillary thyroid cancer cases among atomic bomb survivors (including 21 cases not exposed to atomic bomb radiation), in relation to radiation dose as well as time elapsed since atomic bomb radiation exposure. RET/PTC rearrangements showed significantly increased frequency with increased radiation dose (P(trend) = 0.002). In contrast, BRAF(V600E) mutation was less frequent in cases exposed to higher radiation dose (P(trend) < 0.001). Papillary thyroid cancer subjects harboring RET/PTC rearrangements developed this cancer earlier than did cases with BRAF(V600E) mutation (P = 0.03). These findings were confirmed by multivariate logistic regression analysis. These results suggest that RET/PTC rearrangements play an important role in radiation-associated thyroid carcinogenesis.

  4. Radiation risks in lung cancer screening programs: a comparison with nuclear industry workers and atomic bomb survivors.

    PubMed

    McCunney, Robert J; Li, Jessica

    2014-03-01

    The National Lung Cancer Screening Trial (NLST) demonstrated that screening with low-dose CT (LDCT) scan reduced lung cancer and overall mortality by 20% and 7%, respectively. The LDCT scanning involves an approximate 2-mSv dose, whereas full-chest CT scanning, the major diagnostic study used to follow up nodules, may involve a dose of 8 mSv. Radiation associated with CT scanning and other diagnostic studies to follow up nodules may present an independent risk of lung cancer. On the basis of the NLST, we estimated the incidence and prevalence of nodules detected in screening programs. We followed the Fleischner guidelines for follow-up of nodules to assess cumulative radiation exposure over 20- and 30-year periods. We then evaluated nuclear worker cohort studies and atomic bomb survivor studies to assess the risk of lung cancer from radiation associated with long-term lung cancer screening programs. The findings indicate that a 55-year-old lung screening participant may experience a cumulative radiation exposure of up to 280 mSv over a 20-year period and 420 mSv over 30 years. These exposures exceed those of nuclear workers and atomic bomb survivors. This assessment suggests that long-term (20-30 years) LDCT screening programs are associated with nontrivial cumulative radiation doses. Current lung cancer screening protocols, if conducted over 20- to 30-year periods, can independently increase the risk of lung cancer beyond cigarette smoking as a result of cumulative radiation exposure. Radiation exposures from LDCT screening and follow-up diagnostic procedures exceed lifetime radiation exposures among nuclear power workers and atomic bomb survivors. PMID:24590022

  5. Identifying student and teacher difficulties in interpreting atomic spectra using a quantum model of emission and absorption of radiation

    NASA Astrophysics Data System (ADS)

    Savall-Alemany, Francisco; Domènech-Blanco, Josep Lluís; Guisasola, Jenaro; Martínez-Torregrosa, Joaquín

    2016-06-01

    Our study sets out to identify the difficulties that high school students, teachers, and university students encounter when trying to explain atomic spectra. To do so, we identify the key concepts that any quantum model for the emission and absorption of electromagnetic radiation must include to account for the gas spectra and we then design two questionnaires, one for teachers and the other for students. By analyzing the responses, we conclude that (i) teachers lack a quantum model for the emission and absorption of electromagnetic radiation capable of explaining the spectra, (ii) teachers and students share the same difficulties, and (iii) these difficulties concern the model of the atom, the model of radiation, and the model of the interaction between them.

  6. Ninth Annual Warren K. Sinclair Keynote Address: effects of childhood radiation exposure: an issue from computed tomography scans to Fukushima.

    PubMed

    Mettler, Fred A; Constine, Louis S; Nosske, Dietmar; Shore, Roy E

    2013-11-01

    The acute and chronic effects of radiation on children have been and will continue to be of great social, public health, scientific, and clinical importance. The focus of interest on ionizing radiation and children has been clear for over half a century and ranges from the effects of fallout from nuclear weapons testing to exposures from accidents, natural radiation, and medical procedures. There is a loosely stated notion that "children are three to five times more sensitive to radiation than adults." Is this really true? In fact, children are at greater risk for some health effects, but not all. For a few sequelae, children may be more resistant than adults. Which are those effects? How and why do they occur? While there are clear instances of increased risk of some radiation-induced tumors in children compared to adults, there are other tumor types in which there appears to be little or no difference in risk by age at exposure and some in which published models that assume the same relative increase in risks for child compared to adult exposures apply to nearly all tumor types are not supported by the scientific data. The United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) has a task group producing a comprehensive report on the subject. The factors to be considered include relevant radiation sources; developmental anatomy and physiology; dosimetry; and stochastic, deterministic, and hereditary effects.

  7. Atomic and Molecular Data Needs for Radiation Damage Modeling: Multiscale Approach

    NASA Astrophysics Data System (ADS)

    Yakubovich, Alexander V.; Surdutovich, Eugene; Solov'yov, Andrey V.

    2011-05-01

    We present a brief overview of the multiscale approach towards understanding of the processes responsible for the radiation damage caused by energetic ions. This knowledge is very important, because it can be utilized in the ion-beam cancer therapy, which is one of the most advanced modern techniques to cure certain type of cancer. The central element of the multiscale approach is the theoretical evaluation and quantification of the DNA damage within cell environment. To achieve this goal one needs a significant amount of data on various atomic and molecular processes involved into the cascade of events starting with the ion entering and propagation in the biological medium and resulting in the DNA damage. The discussion of the follow up biological processes are beyond the scope of this brief overview. We consider different paths of the DNA damage and focus on the the illustration of the thermo-mechanical effects caused by the propagation of ions through the biological environment and in particular on the possibility of the creation of the shock waves in the vicinity of the ion tracks. We demonstrate that at the initial stages after ion's passage the shock wave is so strong that it can contribute to the DNA damage due to large pressure gradients developed at the distances of a few nanometers from the ionic tracks. This novel mechanism of the DNA damage provides an important contribution to the cumulative biodamage caused by low-energy secondary electrons, holes and free radicals.

  8. Atomic and Molecular Data Needs for Radiation Damage Modeling: Multiscale Approach

    SciTech Connect

    Yakubovich, Alexander V.; Solov'yov, Andrey V.; Surdutovich, Eugene

    2011-05-11

    We present a brief overview of the multiscale approach towards understanding of the processes responsible for the radiation damage caused by energetic ions. This knowledge is very important, because it can be utilized in the ion-beam cancer therapy, which is one of the most advanced modern techniques to cure certain type of cancer. The central element of the multiscale approach is the theoretical evaluation and quantification of the DNA damage within cell environment. To achieve this goal one needs a significant amount of data on various atomic and molecular processes involved into the cascade of events starting with the ion entering and propagation in the biological medium and resulting in the DNA damage. The discussion of the follow up biological processes are beyond the scope of this brief overview. We consider different paths of the DNA damage and focus on the the illustration of the thermo-mechanical effects caused by the propagation of ions through the biological environment and in particular on the possibility of the creation of the shock waves in the vicinity of the ion tracks. We demonstrate that at the initial stages after ion's passage the shock wave is so strong that it can contribute to the DNA damage due to large pressure gradients developed at the distances of a few nanometers from the ionic tracks. This novel mechanism of the DNA damage provides an important contribution to the cumulative biodamage caused by low-energy secondary electrons, holes and free radicals.

  9. International Test Program for Synergistic Atomic Oxygen and Vacuum Ultraviolet Radiation Exposure of Spacecraft Materials

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K.

    2001-01-01

    The components and materials of spacecraft in low Earth orbit can degrade in thermal and optical performance through interaction with atomic oxygen and vacuum ultraviolet (VUV) radiation, which are predominant in low Earth orbit. Because of the importance of low Earth orbit durability and performance to manufacturers and users, an international test program for assessing the durability of spacecraft materials and components was initiated. Initial tests at the NASA Glenn Research Center consisted of exposure of samples representing a variety of thermal control paints, multilayer insulation materials, and Sun sensors that have been used in space. Materials donated from various international sources were tested alongside materials whose performance is well known, such as Teflon FEP, Kapton H, or Z-93-P white paint. The optical, thermal, or mass loss data generated during the tests were then provided to the participating material suppliers. Data were not published unless the participant donating the material consented to publication. The test program is intended to give spacecraft builders and users a better understanding of degradation processes and effects so that they can improve their predictions of spacecraft performance.

  10. A comprehensive dose reconstruction methodology for former rocketdyne/atomics international radiation workers.

    PubMed

    Boice, John D; Leggett, Richard W; Ellis, Elizabeth Dupree; Wallace, Phillip W; Mumma, Michael; Cohen, Sarah S; Brill, A Bertrand; Chadda, Bandana; Boecker, Bruce B; Yoder, R Craig; Eckerman, Keith F

    2006-05-01

    Incomplete radiation exposure histories, inadequate treatment of internally deposited radionuclides, and failure to account for neutron exposures can be important uncertainties in epidemiologic studies of radiation workers. Organ-specific doses from lifetime occupational exposures and radionuclide intakes were estimated for an epidemiologic study of 5,801 Rocketdyne/Atomics International (AI) radiation workers engaged in nuclear technologies between 1948 and 1999. The entire workforce of 46,970 Rocketdyne/AI employees was identified from 35,042 Kardex work histories cards, 26,136 electronic personnel listings, and 14,189 radiation folders containing individual exposure histories. To obtain prior and subsequent occupational exposure information, the roster of all workers was matched against nationwide dosimetry files from the Department of Energy, the Nuclear Regulatory Commission, the Landauer dosimetry company, the U.S. Army, and the U.S. Air Force. Dosimetry files of other worker studies were also accessed. Computation of organ doses from radionuclide intakes was complicated by the diversity of bioassay data collected over a 40-y period (urine and fecal samples, lung counts, whole-body counts, nasal smears, and wound and incident reports) and the variety of radionuclides with documented intake including isotopes of uranium, plutonium, americium, calcium, cesium, cerium, zirconium, thorium, polonium, promethium, iodine, zinc, strontium, and hydrogen (tritium). Over 30,000 individual bioassay measurements, recorded on 11 different bioassay forms, were abstracted. The bioassay data were evaluated using ICRP biokinetic models recommended in current or upcoming ICRP documents (modified for one inhaled material to reflect site-specific information) to estimate annual doses for 16 organs or tissues taking into account time of exposure, type of radionuclide, and excretion patterns. Detailed internal exposure scenarios were developed and annual internal doses were derived

  11. Remedy for Radiation Fear — Discard the Politicized Science

    PubMed Central

    Cuttler, Jerry M.

    2014-01-01

    Seeking a remedy for the radiation fear in Japan, the author re-examined an article on radiation hormesis. It describes the background for this fear and evidence in the first UNSCEAR report of a reduction in leukemia of the Hiroshima survivors in the low dose zone. The data are plotted and dose-response models are drawn. While UNSCEAR suggested the extra leukemia incidence is proportional to radiation dose, the data are consistent with a hormetic J-shape and a threshold at about 100 rem (1 Sv). UNSCEAR data on lifespan reduction of mammals exposed continuously to gamma rays indicate a 2 gray/year threshold. This contradicts the conceptual basis for radiation protection and risk determination established in 1956–58. In this paper, beneficial effects and thresholds for harmful effects are discussed, and the biological mechanism is explained. The key point: the rate of DNA damage (double-strand breaks) caused by background radiation is 1000 times less than the endogenous (spontaneous) rate. It is the effect of radiation on an organism’s very powerful adaptive protection systems that determines the dose-response characteristic. Low radiation up-regulates the protection systems, while high radiation impairs these systems. The remedy for radiation fear is to expose and discard the politicized science. PMID:24910587

  12. Simulation of the synergistic low Earth orbit effects of vacuum thermal cycling, vacuum UV radiation, and atomic oxygen

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Degroh, Kim K.; Stidham, Curtis R.; Stueber, Thomas J.; Dever, Therese M.; Rodriguez, Elvin; Terlep, Judith A.

    1992-01-01

    In order to assess the low Earth orbit (LEO) durability of candidate space materials, it is necessary to use ground laboratory facilities which provide LEO environmental effects. A facility combining vacuum thermal cycling and vacuum ultraviolet (VUV) radiation has been designed and constructed at NASA Lewis Research Center for this purpose. This facility can also be operated without the VUV lamps. An additional facility can be used to provide VUV exposure only. By utilizing these facilities, followed by atomic oxygen exposure in an RF plasma asher, the effects of the individual vacuum thermal cycling and VUV environments can be compared to the effect of the combined vacuum thermal cycling/VUV environment on the atomic oxygen durability of materials. The synergistic effects of simulated LEO environmental conditions on materials were evaluated by first exposing materials to vacuum thermal cycling, VUV, and vacuum thermal cycling/VUV environments followed by exposure to atomic oxygen in an RP plasma asher. Candidate space power materials such as atomic oxygen protected polyimides and solar concentrator mirrors were evaluated using these facilities. Characteristics of the Vacuum Thermal Cycling/VUV Exposure Facility which simulates the temperature sequences and solar ultraviolet radiation exposure that would be experienced by a spacecraft surface in LEO are discussed. Results of durability evaluations of some candidate space power materials to the simulated LEO environmental conditions will also be discussed. Such results have indicated that for some materials, atomic oxygen durability is affected by previous exposure to thermal cycling and/or VUV exposure.

  13. Effects of atomic oxygen and ultraviolet radiation on candidate elastomeric materials for long duration missions. Test series no.1

    NASA Technical Reports Server (NTRS)

    Linton, R. C.; Finckenor, M. M.; Kamenetzky, R. R.; Gray, P.

    1993-01-01

    Research was conducted at MSFC on the behavior of elastomeric materials after exposure to simulated space environment. Silicone S383 and Viton V747 samples were exposed to thermal vacuum, ultraviolet radiation, and atomic oxygen and then evaluated for changes in material properties. Characterization of the elastomeric materials included weight, hardness, optical inspection under normal and black light, spectrofluorescence, solar absorptance and emittance, Fourier transform infrared spectroscopy, and permeability. These results indicate a degree of sensitivity to exposure and provided some evidence of UV and atomic oxygen synergism.

  14. Worker radiation doses in the United States at the dawn of the atomic era (1940--1960)

    SciTech Connect

    Strom, D.J.; Smith, M.H.; Swinth, K.L.; Pettengill, H.J.

    1994-06-01

    Radiation doses to workers at the Manhattan Engineer District (MED) and US Atomic Energy Commission (AEC) sites due to external irradiation during 1940--1960 are reviewed. Categorized radiation dose data were available from AEC annual reports for some years. Annual individual radiation dose data for ten MED/AEC sites for all years were available from the US Department of Energy`s (DOE) Comprehensive Epidemiologic Data Resource (CEDR). These data are combined to produce an estimate of external collective dose equivalent to 172,000 person-rems (1720 person-Sv) for 1940--1960. During this period there were 41 overexposures, 19 criticality incidents, and 3 deaths due to acute radiation syndrome among several hundred thousand workers.

  15. Workshop Report on Atomic Bomb Dosimetry--Residual Radiation Exposure: Recent Research and Suggestions for Future Studies

    SciTech Connect

    2013-06-06

    There is a need for accurate dosimetry for studies of health effects in the Japanese atomic bomb survivors because of the important role that these studies play in worldwide radiation protection standards. International experts have developed dosimetry systems, such as the Dosimetry System 2002 (DS02), which assess the initial radiation exposure to gamma rays and neutrons but only briefly consider the possibility of some minimal contribution to the total body dose by residual radiation exposure. In recognition of the need for an up-to-date review of the topic of residual radiation exposure in Hiroshima and Nagasaki, recently reported studies were reviewed at a technical session at the 57th Annual Meeting of the Health Physics Society in Sacramento, California, 22-26 July 2012. A one-day workshop was also held to provide time for detailed discussion of these newer studies and to evaluate their potential use in clarifying the residual radiation exposures to the atomic-bomb survivors at Hiroshima and Nagasaki. Suggestions for possible future studies are also included in this workshop report.

  16. Workshop report on atomic bomb dosimetry-residual radiation exposure: recent research and suggestions for future studies.

    PubMed

    Kerr, George D; Egbert, Stephen D; Al-Nabulsi, Isaf; Beck, Harold L; Cullings, Harry M; Endo, Satoru; Hoshi, Masaharu; Imanaka, Tetsuji; Kaul, Dean C; Maruyama, Satoshi; Reeves, Glen I; Ruehm, Werner; Sakaguchi, Aya; Simon, Steven L; Spriggs, Gregory D; Stram, Daniel O; Tonda, Tetsuji; Weiss, Joseph F; Weitz, Ronald L; Young, Robert W

    2013-08-01

    There is a need for accurate dosimetry for studies of health effects in the Japanese atomic bomb survivors because of the important role that these studies play in worldwide radiation protection standards. International experts have developed dosimetry systems, such as the Dosimetry System 2002 (DS02), which assess the initial radiation exposure to gamma rays and neutrons but only briefly consider the possibility of some minimal contribution to the total body dose by residual radiation exposure. In recognition of the need for an up-to-date review of the topic of residual radiation exposure in Hiroshima and Nagasaki, recently reported studies were reviewed at a technical session at the 57th Annual Meeting of the Health Physics Society in Sacramento, California, 22-26 July 2012. A one-day workshop was also held to provide time for detailed discussion of these newer studies and to evaluate their potential use in clarifying the residual radiation exposures to the atomic-bomb survivors at Hiroshima and Nagasaki. Suggestions for possible future studies are also included in this workshop report. PMID:23799498

  17. Workshop report on atomic bomb dosimetry-residual radiation exposure: recent research and suggestions for future studies.

    PubMed

    Kerr, George D; Egbert, Stephen D; Al-Nabulsi, Isaf; Beck, Harold L; Cullings, Harry M; Endo, Satoru; Hoshi, Masaharu; Imanaka, Tetsuji; Kaul, Dean C; Maruyama, Satoshi; Reeves, Glen I; Ruehm, Werner; Sakaguchi, Aya; Simon, Steven L; Spriggs, Gregory D; Stram, Daniel O; Tonda, Tetsuji; Weiss, Joseph F; Weitz, Ronald L; Young, Robert W

    2013-08-01

    There is a need for accurate dosimetry for studies of health effects in the Japanese atomic bomb survivors because of the important role that these studies play in worldwide radiation protection standards. International experts have developed dosimetry systems, such as the Dosimetry System 2002 (DS02), which assess the initial radiation exposure to gamma rays and neutrons but only briefly consider the possibility of some minimal contribution to the total body dose by residual radiation exposure. In recognition of the need for an up-to-date review of the topic of residual radiation exposure in Hiroshima and Nagasaki, recently reported studies were reviewed at a technical session at the 57th Annual Meeting of the Health Physics Society in Sacramento, California, 22-26 July 2012. A one-day workshop was also held to provide time for detailed discussion of these newer studies and to evaluate their potential use in clarifying the residual radiation exposures to the atomic-bomb survivors at Hiroshima and Nagasaki. Suggestions for possible future studies are also included in this workshop report.

  18. Hydrodynamic, Atomic Kinetic, and Monte Carlo Radiation Transfer Models of the X-ray Spectra of Compact Binaries

    SciTech Connect

    Mauche, C W; Liedahl, D A; Akiyama, S; Plewa, T

    2008-02-08

    We describe the results of an effort, funded by the Lawrence Livermore National Laboratory Directed Research and Development Program, to model, using FLASH time-dependent adaptive-mesh hydrodynamic simulations, XSTAR photoionization calculations, HULLAC atomic data, and Monte Carlo radiation transport, the radiatively-driven photoionized wind and accretion flow of high-mass X-ray binaries (HMXBs). In this final report, we describe the purpose, approach, and technical accomplishments of this effort, including maps of the density, temperature, velocity, ionization parameter, and emissivity distributions of the X-ray emission lines of the well-studied HMXB Vela X-1.

  19. High-resolution X-ray spectroscopy of hollow atoms created in plasma heated by subpicosecond laser radiation

    SciTech Connect

    Faenov, A.Ya.; Magunov, A.I.; Pikuz, T.A.

    1997-10-01

    The investigations of ultrashort (0.4-0.6 ps) laser pulse radiation interaction with solid targets have been carried out. The Trident subpicosecond laser system was used for plasma creation. The X-ray plasma emission was investigated with the help of high-resolution spectrographs with spherically bent mica crystals. It is shown that when high contrast ultrashort laser pulses were used for plasma heating its emission spectra could not be explained in terms of commonly used theoretical models, and transitions in so called {open_quotes}hollow atoms{close_quotes} must be taken into account for adequate description of plasma radiation.

  20. Mutation, radiation, and species survival: The genetics studies of the Atomic Bomb Casualty Commission in Hiroshima and Nagasaki, Japan

    SciTech Connect

    Lindee, M.S.

    1990-01-01

    This is an analysis of the work of the Atomic Bomb Casualty Commission, an American agency which studied the effects of radiation on survivors of the atomic bombings at Hiroshima and Nagasaki, Japan, 1947-1975. Funded by the U.S. Atomic Energy Commission and directed by the National Academy of Sciences-National Research Council, the ABCC was the largest and longest medical study of the estimated 300,000 survivors. The morphological genetics study dominated the ABCCs first decade. James Neel and his principal collaborator William J. Schull tracked more than 76,000 pregnancies. Their results (1956) suggested the bombs radiation had no detectable impact on the offspring of survivors. Though geneticists knew that radiation caused heritable mutations in experimental organisms such as Drosophila, and believed it caused mutations in humans, the Neel-Schull findings were not a surprise. The practical difficulties of the study, and the relatively small increase in abnormal births to be expected, made a finding of significant effects unlikely. The Neel-Schull approach reflected the scientific debate over genetic load, and the Muller-Dobzhansky classical-balance controversy. Yet the findings also reflected the post-war debate over atomic energy and weapons testing. Many extra-scientific forces militated against a finding of positive effects at Hiroshima and Nagasaki. Negative findings were consistent with the needs of the Atomic Energy Commission, the State Department and the U.S. military. This dissertation explores how both the scientific debate about genetic load, and the political debate about atmospheric weapons testing, shaped this complex epidemiological study.

  1. Risk of cancer among children exposed to atomic bomb radiation in utero: a review.

    PubMed

    Kato, H; Yoshimoto, Y; Schull, W J

    1989-01-01

    We have examined the risk for cancer (incidence) over a period of 40 years, 1945-1984, among 1829 persons exposed in utero to the atomic bombing of Hiroshima and Nagasaki. This report adds eight years of follow-up to a previous report which was confined to mortality. Only two cases of childhood cancer were observed among these survivors in the first 14 years of life; both had been heavily exposed. Subsequent cancers have all been of the adult type. Not only did these latter cancers occur earlier in persons exposed to greater than 0.30 Gy than in unexposed (0 Gy) but the incidence continues to increase, and the crude cumulative incidence rate 40 years after the bombing is 3.9-fold greater in persons exposed to greater than 0.30 Gy. In the observation period 1950-1984, the relative risk for cancer at 1 Gy, based on the absorbed dose to the mother's uterus as estimated by the Dosimetry System 1986 (DS86), is 3.77 with a 95% confidence interval of 1.14-13.48. For all persons exposed to greater than 0.01 Gy, the average excess risk per 10(4) person-year-Gy is 6.57 (0.07-14.49), and the estimated attributable risk is 40.9% (2.9-90.2%). These results, when viewed in the perspective of fetal doses, suggest that susceptibility to radiation-induced cancers is higher in survivors exposed prenatally than in those exposed postnatally (at least, those exposed as adults). However, definitive conclusions must await further follow-up studies.

  2. Activation of extended red emission photoluminescence in carbon solids by exposure to atomic hydrogen and UV radiation

    NASA Technical Reports Server (NTRS)

    Furton, Douglas G.; Witt, Adolf N.

    1993-01-01

    We report on new laboratory results which relate directly to the observation of strongly enhanced extended red emission (ERE) by interstellar dust in H2 photodissociation zones. The ERE has been attributed to photoluminescence by hydrogenated amorphous carbon (HAC). We are demonstrating that exposure to thermally dissociated atomic hydrogen will restore the photoluminescence efficiency of previously annealed HAC. Also, pure amorphous carbon (AC), not previously photoluminescent, can be induced to photoluminesce by exposure to atomic hydrogen. This conversion of AC into HAC is greatly enhanced by the presence of UV irradiation. The presence of dense, warm atomic hydrogen and a strong UV radiation field are characteristic environmental properties of H2 dissociation zones. Our results lend strong support to the HAC photoluminescence explanation for ERE.

  3. Superradiant effects on pulse propagation in resonant media. [atomic excitations/coherent radiation - operators (mathematics)/matrices (mathematics)

    NASA Technical Reports Server (NTRS)

    Lee, C.

    1975-01-01

    Adopting the so-called genealogical construction, the eigenstates of collective operators can be expressed corresponding to a specified mode for an N-atom system in terms of those for an (N-1)-atom system. Matrix element of a collective operator of an arbitrary mode is presented which can be written as the product of an m-dependent factor and an m-independent reduced matrix element (RME). A set of recursion formulas for the RME was obtained. A graphical representation of the RME on the branching diagram for binary irreducible representations of permutation groups was then introduced. This gave a simple and systematic way of calculating the RME. Results show explicitly the geometry dependence of superradiance and the relative importance of r-conserving and r-nonconserving processes and clears up the chief difficulty encounted in the problem of N two-level atoms, spread over large regions, interacting with a multimode radiation field.

  4. Ultracold magnetically tunable interactions without radiative-charge-transfer losses between Ca+, Sr+, Ba+, and Yb+ ions and Cr atoms

    NASA Astrophysics Data System (ADS)

    Tomza, Michał

    2015-12-01

    The Ca+, Sr+, Ba+, and Yb+ ions immersed in an ultracold gas of the Cr atoms are proposed as experimentally feasible heteronuclear systems in which ion-atom interactions at ultralow temperatures can be controlled with magnetically tunable Feshbach resonances without charge transfer and radiative losses. Ab initio techniques are applied to investigate electronic-ground-state properties of the (CaCr)+, (SrCr)+, (BaCr)+, and (YbCr)+ molecular ions. The potential energy curves, permanent electric dipole moments, and static electric dipole polarizabilities are computed. The spin-restricted open-shell coupled-cluster method restricted to single, double, and noniterative triple excitations and the multireference configuration-interaction method restricted to single and double excitations are employed. The scalar relativistic effects are included within the small-core energy-consistent pseudopotentials. The leading long-range induction and dispersion interaction coefficients are also reported. Finally, magnetic Feshbach resonances between the Ca+, Sr+, Ba+, and Yb+ ions interacting with the Cr atoms are analyzed. The present proposal opens the way towards robust quantum simulations and computations with ultracold ion-atom systems free of radiative charge-transfer losses.

  5. Analytical solutions of the time-dependent radiation force for a two-level atom interacting with a continuous-wave single-mode laser

    SciTech Connect

    Noh, Heung-Ryoul; Jhe, Wonho

    2010-09-15

    This work presents an analytical calculation of the time-dependent radiation forces on a two-level atom interacting with a single-mode laser field. Such a closed and compact expression of the radiation forces is derived by solving the optical Bloch equations analytically. It is confirmed, in particular, that the radiation force consists of reactive as well as dissipative components, whose explicit analytical forms of the temporal solutions can be explicitly obtained. The succinct analytical solutions of the radiation forces may be helpful for a convenient and intuitive description of the complex atomic dynamics such as interaction with various laser fields.

  6. Metabolic Profile as a Potential Modifier of Long-Term Radiation Effects on Peripheral Lymphocyte Subsets in Atomic Bomb Survivors.

    PubMed

    Yoshida, Kengo; Nakashima, Eiji; Kyoizumi, Seishi; Hakoda, Masayuki; Hayashi, Tomonori; Hida, Ayumi; Ohishi, Waka; Kusunoki, Yoichiro

    2016-09-01

    Immune system impairments reflected by the composition and function of circulating lymphocytes are still observed in atomic bomb survivors, and metabolic abnormalities including altered blood triglyceride and cholesterol levels have also been detected in such survivors. Based on closely related features of immune and metabolic profiles of individuals, we investigated the hypothesis that long-term effects of radiation exposure on lymphocyte subsets might be modified by metabolic profiles in 3,113 atomic bomb survivors who participated in health examinations at the Radiation Effect Research Foundation, Hiroshima and Nagasaki, in 2000-2002. The lymphocyte subsets analyzed involved T-, B- and NK-cell subsets, and their percentages in the lymphocyte fraction were assessed using flow cytometry. Health examinations included metabolic indicators, body mass index, serum levels of total cholesterol, high-density lipoprotein cholesterol, C-reactive protein and hemoglobin A1c, as well as diabetes and fatty liver diagnoses. Standard regression analyses indicated that several metabolic indicators of obesity/related disease, particularly high-density lipoprotein cholesterol levels, were positively associated with type-1 helper T- and B-cell percentages but were inversely associated with naïve CD4 T and NK cells. A regression analysis adjusted for high-density lipoprotein cholesterol revealed a radiation dose relationship with increasing NK-cell percentage. Additionally, an interaction effect was suggested between radiation dose and C-reactive protein on B-cell percentage with a negative coefficient of the interaction term. Collectively, these findings suggest that radiation exposure and subsequent metabolic profile changes, potentially in relationship to obesity-related inflammation, lead to such long-term alterations in lymphocyte subset composition. Because this study is based on cross-sectional and exploratory analyses, the implications regarding radiation exposure, metabolic

  7. Evaluation of systemic markers of inflammation in atomic-bomb survivors with special reference to radiation and age effects

    PubMed Central

    Hayashi, Tomonori; Morishita, Yukari; Khattree, Ravindra; Misumi, Munechika; Sasaki, Keiko; Hayashi, Ikue; Yoshida, Kengo; Kajimura, Junko; Kyoizumi, Seishi; Imai, Kazue; Kusunoki, Yoichiro; Nakachi, Kei

    2012-01-01

    Past exposure to atomic bomb (A-bomb) radiation has exerted various long-lasting deleterious effects on the health of survivors. Some of these effects are seen even after >60 yr. In this study, we evaluated the subclinical inflammatory status of 442 A-bomb survivors, in terms of 8 inflammation-related cytokines or markers, comprised of plasma levels of reactive oxygen species (ROS), interleukin (IL)-6, tumor necrosis factor α (TNF-α), C-reactive protein (CRP), IL-4, IL-10, and immunoglobulins, and erythrocyte sedimentation rate (ESR). The effects of past radiation exposure and natural aging on these markers were individually assessed and compared. Next, to assess the biologically significant relationship between inflammation and radiation exposure or aging, which was masked by the interrelationship of those cytokines/markers, we used multivariate statistical analyses and evaluated the systemic markers of inflammation as scores being calculated by linear combinations of selected cytokines and markers. Our results indicate that a linear combination of ROS, IL-6, CRP, and ESR generated a score that was the most indicative of inflammation and revealed clear dependences on radiation dose and aging that were found to be statistically significant. The results suggest that collectively, radiation exposure, in conjunction with natural aging, may enhance the persistent inflammatory status of A-bomb survivors.—Hayashi, T., Morishita, Y., Khattree, R., Misumi, M., Sasaki, K., Hayashi, I., Yoshida, K., Kajimura, J., Kyoizumi, S., Imai, K., Kusunoki, Y., Nakachi, K. Evaluation of systemic markers of inflammation in atomic-bomb survivors with special reference to radiation and age effects. PMID:22872680

  8. Metabolic Profile as a Potential Modifier of Long-Term Radiation Effects on Peripheral Lymphocyte Subsets in Atomic Bomb Survivors.

    PubMed

    Yoshida, Kengo; Nakashima, Eiji; Kyoizumi, Seishi; Hakoda, Masayuki; Hayashi, Tomonori; Hida, Ayumi; Ohishi, Waka; Kusunoki, Yoichiro

    2016-09-01

    Immune system impairments reflected by the composition and function of circulating lymphocytes are still observed in atomic bomb survivors, and metabolic abnormalities including altered blood triglyceride and cholesterol levels have also been detected in such survivors. Based on closely related features of immune and metabolic profiles of individuals, we investigated the hypothesis that long-term effects of radiation exposure on lymphocyte subsets might be modified by metabolic profiles in 3,113 atomic bomb survivors who participated in health examinations at the Radiation Effect Research Foundation, Hiroshima and Nagasaki, in 2000-2002. The lymphocyte subsets analyzed involved T-, B- and NK-cell subsets, and their percentages in the lymphocyte fraction were assessed using flow cytometry. Health examinations included metabolic indicators, body mass index, serum levels of total cholesterol, high-density lipoprotein cholesterol, C-reactive protein and hemoglobin A1c, as well as diabetes and fatty liver diagnoses. Standard regression analyses indicated that several metabolic indicators of obesity/related disease, particularly high-density lipoprotein cholesterol levels, were positively associated with type-1 helper T- and B-cell percentages but were inversely associated with naïve CD4 T and NK cells. A regression analysis adjusted for high-density lipoprotein cholesterol revealed a radiation dose relationship with increasing NK-cell percentage. Additionally, an interaction effect was suggested between radiation dose and C-reactive protein on B-cell percentage with a negative coefficient of the interaction term. Collectively, these findings suggest that radiation exposure and subsequent metabolic profile changes, potentially in relationship to obesity-related inflammation, lead to such long-term alterations in lymphocyte subset composition. Because this study is based on cross-sectional and exploratory analyses, the implications regarding radiation exposure, metabolic

  9. Quantification of Quantum Entanglement in a Multiparticle System of Two-Level Atoms Interacting with a Squeezed Vacuum State of the Radiation Field

    NASA Astrophysics Data System (ADS)

    Deb, Ram Narayan

    2016-07-01

    We quantify multiparticle quantum entanglement in a system of N two-level atoms interacting with a squeezed vacuum state of the electromagnetic field. We calculate the amount of quantum entanglement present among one hundred such two-level atoms and also show the variation of that entanglement with the radiation field parameter. We show the continuous variation of the amount of quantum entanglement as we continuously increase the number of atoms from N = 2 to N = 100. We also discuss that the multiparticle correlations among the N two-level atoms are made up of all possible bipartite correlations among the N atoms.

  10. QED Energy Approach to Atoms and Nuclei in a Strong Laser Field: Radiation Lines

    SciTech Connect

    Glushkov, A. V.

    2010-10-29

    The consistent approach to the 'atom, nucleus - realistic laser field' interaction is presented and based on the QED and Gell-Mann and Low S-matrix formalism. The method is applied to studying the multi-photon resonance width and shift in the atom of H in a laser pulse.

  11. Evaluation of systemic markers of inflammation in atomic-bomb survivors with special reference to radiation and age effects.

    PubMed

    Hayashi, Tomonori; Morishita, Yukari; Khattree, Ravindra; Misumi, Munechika; Sasaki, Keiko; Hayashi, Ikue; Yoshida, Kengo; Kajimura, Junko; Kyoizumi, Seishi; Imai, Kazue; Kusunoki, Yoichiro; Nakachi, Kei

    2012-11-01

    Past exposure to atomic bomb (A-bomb) radiation has exerted various long-lasting deleterious effects on the health of survivors. Some of these effects are seen even after >60 yr. In this study, we evaluated the subclinical inflammatory status of 442 A-bomb survivors, in terms of 8 inflammation-related cytokines or markers, comprised of plasma levels of reactive oxygen species (ROS), interleukin (IL)-6, tumor necrosis factor α (TNF-α), C-reactive protein (CRP), IL-4, IL-10, and immunoglobulins, and erythrocyte sedimentation rate (ESR). The effects of past radiation exposure and natural aging on these markers were individually assessed and compared. Next, to assess the biologically significant relationship between inflammation and radiation exposure or aging, which was masked by the interrelationship of those cytokines/markers, we used multivariate statistical analyses and evaluated the systemic markers of inflammation as scores being calculated by linear combinations of selected cytokines and markers. Our results indicate that a linear combination of ROS, IL-6, CRP, and ESR generated a score that was the most indicative of inflammation and revealed clear dependences on radiation dose and aging that were found to be statistically significant. The results suggest that collectively, radiation exposure, in conjunction with natural aging, may enhance the persistent inflammatory status of A-bomb survivors.

  12. Radiation risk of individual multifactorial diseases in offspring of the atomic-bomb survivors: a clinical health study.

    PubMed

    Tatsukawa, Yoshimi; Cologne, John B; Hsu, Wan-Ling; Yamada, Michiko; Ohishi, Waka; Hida, Ayumi; Furukawa, Kyoji; Takahashi, Norio; Nakamura, Nori; Suyama, Akihiko; Ozasa, Kotaro; Akahoshi, Masazumi; Fujiwara, Saeko; Shore, Roy

    2013-06-01

    There is no convincing evidence regarding radiation-induced heritable risks of adult-onset multifactorial diseases in humans, although it is important from the standpoint of protection and management of populations exposed to radiation. The objective of the present study was to examine whether parental exposure to atomic-bomb (A-bomb) radiation led to an increased risk of common polygenic, multifactorial diseases-hypertension, hypercholesterolaemia, diabetes mellitus, angina pectoris, myocardial infarction or stroke-in the first-generation (F1) offspring of A-bomb survivors. A total of 11,951 F1 offspring of survivors in Hiroshima or Nagasaki, conceived after the bombing, underwent health examinations to assess disease prevalence. We found no evidence that paternal or maternal A-bomb radiation dose, or the sum of their doses, was associated with an increased risk of any multifactorial diseases in either male or female offspring. None of the 18 radiation dose-response slopes, adjusted for other risk factors for the diseases, was statistically significantly elevated. However, the study population is still in mid-life (mean age 48.6 years), and will express much of its multifactorial disease incidence in the future, so ongoing longitudinal follow-up will provide increasingly informative risk estimates regarding hereditary genetic effects for incidence of adult-onset multifactorial disease.

  13. Adverse event reporting and developments in radiation biology after normal tissue injury: International Atomic Energy Agency consultation

    SciTech Connect

    Chen Yuhchyau . E-mail: Yuhchyau_chen@urmc.rochester.edu; Trotti, Andy; Coleman, C. Norman; Machtay, Mitchell; Mirimanoff, Rene O.; Hay, John; O'Brien, Peter C.; El-Gueddari, Brahim; Salvajoli, Joao V.; Jeremic, Branislav

    2006-04-01

    Purpose: Recent research has enhanced our understanding of radiation injury at the molecular-cellular and tissue levels; significant strides have occurred in standardization of adverse event reporting in clinical trials. In response, the International Atomic Energy Agency, through its Division of Human Health and its section for Applied Radiation Biology and Radiotherapy, organized a consultation meeting in Atlanta (October 2, 2004) to discuss developments in radiobiology, normal tissue reactions, and adverse event reporting. Methods and Materials: Representatives from cooperative groups of African Radiation Oncology Group, Curriculo Radioterapeutica Ibero Latino Americana, European Organization for Research and Treatment of Cancer, National Cancer Institute of Canada Clinical Trials Group, Radiation Therapy Oncology Group, and Trans-Tasman Radiation Oncology Group held the meeting discussion. Results: Representatives of major radiotherapy groups/organizations and prominent leaders in radiotherapy discussed current understanding of normal tissue radiobiologic effects, the design and implementation of future clinical and translational projects for normal tissue injury, and the standardization of adverse-event reporting worldwide. Conclusions: The consensus was to adopt NCI comprehensive adverse event reporting terminology and grading system (CTCAE v3.0) as the new standard for all cooperative group trials. Future plans included the implementation of coordinated research projects focusing on normal tissue biomarkers and data collection methods.

  14. Evaluation of systemic markers of inflammation in atomic-bomb survivors with special reference to radiation and age effects.

    PubMed

    Hayashi, Tomonori; Morishita, Yukari; Khattree, Ravindra; Misumi, Munechika; Sasaki, Keiko; Hayashi, Ikue; Yoshida, Kengo; Kajimura, Junko; Kyoizumi, Seishi; Imai, Kazue; Kusunoki, Yoichiro; Nakachi, Kei

    2012-11-01

    Past exposure to atomic bomb (A-bomb) radiation has exerted various long-lasting deleterious effects on the health of survivors. Some of these effects are seen even after >60 yr. In this study, we evaluated the subclinical inflammatory status of 442 A-bomb survivors, in terms of 8 inflammation-related cytokines or markers, comprised of plasma levels of reactive oxygen species (ROS), interleukin (IL)-6, tumor necrosis factor α (TNF-α), C-reactive protein (CRP), IL-4, IL-10, and immunoglobulins, and erythrocyte sedimentation rate (ESR). The effects of past radiation exposure and natural aging on these markers were individually assessed and compared. Next, to assess the biologically significant relationship between inflammation and radiation exposure or aging, which was masked by the interrelationship of those cytokines/markers, we used multivariate statistical analyses and evaluated the systemic markers of inflammation as scores being calculated by linear combinations of selected cytokines and markers. Our results indicate that a linear combination of ROS, IL-6, CRP, and ESR generated a score that was the most indicative of inflammation and revealed clear dependences on radiation dose and aging that were found to be statistically significant. The results suggest that collectively, radiation exposure, in conjunction with natural aging, may enhance the persistent inflammatory status of A-bomb survivors. PMID:22872680

  15. Atomic scale simulations of pyrochlore oxides with a tight-binding variable-charge model: implications for radiation tolerance.

    PubMed

    Sattonnay, G; Tétot, R

    2014-02-01

    Atomistic simulations with new interatomic potentials derived from a tight-binding variable-charge model were performed in order to investigate the lattice properties and the defect formation energies in Gd2Ti2O7 and Gd2Zr2O7 pyrochlores. The main objective was to determine the role played by the defect stability on the radiation tolerance of these compounds. Calculations show that the titanate has a more covalent character than the zirconate. Moreover, the properties of oxygen Frenkel pairs, cation antisite defects and cation Frenkel pairs were studied. In Gd2Ti2O7 the cation antisite defect and the Ti-Frenkel pair are not stable: they evolve towards more stable defect configurations during the atomic relaxation process. This phenomenon is driven by a decrease of the Ti coordination number down to five which leads to a local atomic reorganization and strong structural distortions around the defects. These kinds of atomic rearrangements are not observed around defects in Gd2Zr2O7. Therefore, the defect stability in A2B2O7 depends on the ability of B atoms to accommodate high coordination number (higher than six seems impossible for Ti). The accumulation of structural distortions around Ti-defects due to this phenomenon could drive the Gd2Ti2O7 amorphization induced by irradiation.

  16. Multiple myeloma among atomic bomb survivors in Hiroshima and Nagasaki, 1950-76: relationship to radiation dose absorbed by marrow

    SciTech Connect

    Ichimaru, M.; Ishimaru, T.; Mikami, M.; Matsunaga, M.

    1982-08-01

    The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimated risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure.

  17. Multiple myeloma among atomic bomb survivors in Hiroshima and Nagasaki, 1950-76: relationship to radiation dose absorbed by marrow

    SciTech Connect

    Ichimaru, M.; Ishimaru, T.; Mikami, M.; Matsunaga, M.

    1982-08-01

    The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimaged risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure.

  18. Multipolar theory of blackbody radiation shift of atomic energy levels and its implications for optical lattice clocks

    SciTech Connect

    Porsev, Sergey G.; Derevianko, Andrei

    2006-08-15

    Blackbody radiation (BBR) shifts of the {sup 3}P{sub 0}-{sup 1}S{sub 0} clock transition in the divalent atoms Mg, Ca, Sr, and Yb are evaluated. The dominant electric-dipole contributions are computed using accurate relativistic many-body techniques of atomic structure. At room temperatures, the resulting uncertainties in the E1 BBR shifts are large and substantially affect the projected 10{sup -18} fractional accuracy of the optical-lattice-based clocks. A peculiarity of these clocks is that the characteristic BBR wavelength is comparable to the {sup 3}P fine-structure intervals. To evaluate relevant M1 and E2 contributions, a theory of multipolar BBR shifts is developed. The resulting corrections, although presently masked by the uncertainties in the E1 contribution, are required at the 10{sup -18} accuracy goal.

  19. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Characteristics of the scattering of neutral atoms by two counterpropagating pulsed optical fields

    NASA Astrophysics Data System (ADS)

    Grinchuk, V. A.; Grishina, I. A.; Kuzin, E. F.; Nagaeva, M. L.; Ryabenko, G. A.; Yakovlev, V. P.

    1994-04-01

    The scattering of neutral sodium atoms by a strong field of two counterpropagating (incident on and reflected from a mirror) short laser pulses was used in an experimental investigation of a stimulated radiation pressure. The reasons for the anomalous frequency structure in the scattering of atoms were identified. The oscillatory nature of the dependence of the scattering on the detuning from resonance was found to be significant in strong laser radiation fields. The oscillation period depended on the distance between the reflecting mirror and the atomic beam.

  20. Decay of the excited state 32 P 3/2 of sodium atoms taking into account radiation trapping

    NASA Astrophysics Data System (ADS)

    Kosarev, N. I.

    2008-01-01

    The effective lifetime of the excited state 32 P 3/2 of sodium atoms corresponding to the transition with λ = 589 nm has been studied numerically. It is shown that the nonmonotonic behavior of the dependence of the Biberman-Holstein escape factor on the optical thickness of sodium vapor measured in the experiment (A. Romberg and H.-J. Kunze, J. Quant. Spectrosc. Radiat. Transfer 39 (2), 99 (1988)) should not be attributed to the manifestation of the effects of partial frequency redistribution.

  1. Photoionization of atoms and small molecules using synchrotron radiation. [SF/sub 6/, SiF/sub 4/

    SciTech Connect

    Ferrett, T.A.

    1986-11-01

    The combination of synchrotron radiation and time-of-flight electron spectroscopy has been used to study the photoionization dynamics of atoms (Li) and small molecules (SF/sub 6/, SiF/sub 4/, and SO/sub 2/). Partial cross sections and angular distribution asymmetry parameters have been measured for Auger electrons and photoelectrons as functions of photon energy. Emphasis is on the basic understanding of electron correlation and resonant effects as manifested in the photoemission spectra for these systems. 254 refs., 46 figs., 10 tabs.

  2. Redistribution of scattered radiation by collisions in the nonimpact region of the spectral line profile. [light scattering from atomic interactions

    NASA Technical Reports Server (NTRS)

    Cooper, J.

    1979-01-01

    The scattering of radiation in the presence of collisions can be described quantum-mechanically in terms of essentially two processes. The first may be thought of as an absorption to the excited state followed subsequently (after propagating in the excited state) by emission. This gives rise to radiation redistributed about the transition frequency. The effects of m-degeneracy are particularly interesting for this first process. As an example a case is considered in which the incident frequency is in the quasi-static line wing, while the scattered frequency is close to the line center. It is found that under these circumstances the dominant contribution from this process in the scattered spectrum is obtained for an absorption of the incident frequency taking place during a strong (close) collision and reemission of the scattered frequency when the atom is essentially unperturbed

  3. Delayed effects of low-dose radiation on cellular immunity in atomic bomb survivors residing in the United States.

    PubMed

    Bloom, E T; Akiyama, M; Kusunoki, Y; Makinodan, T

    1987-05-01

    Several parameters of cellular immune function were assessed among persons who survived the 1945 atomic bombs in Hiroshima and Nagasaki but who now reside in the United States. The subjects in this study were exposed to various low doses (T65D) of radiation at the time of the bomb. More than half received an estimated 0 Gy (S0 group). Of those exposed to more radiation (S+ group), nearly 90% received less than 0.50 Gy (50 rad). Lymphocytes were isolated from the peripheral blood of these individuals and were assessed for the following parameters of cellular immunity: mitogenic response to phytohemagglutinin, mitogenic response to allogeneic lymphocytes, natural cell-mediated cytotoxicity (NCMC), and interferon production. In every case, the response of the S+ group was greater than that of the S0 group, although only the difference for NCMC was statistically significant. Results of studies presently being performed on A-bomb survivors residing in Hiroshima do not confirm this difference. Therefore, it is difficult to say whether the increase in natural cytotoxicity observed among the American and not the Japanese A-bomb survivors exposed to very low doses of radiation is a hormetic effect which was modulated by post-radiation environmental conditions or a result of selective migration.

  4. Radiation pressure excitation of Low Temperature Atomic Force & Magnetic Force Microscope (LT-AFM/MFM) for Imaging

    NASA Astrophysics Data System (ADS)

    Karci, Ozgur; Celik, Umit; Oral, Ahmet; NanoMagnetics Instruments Ltd. Team; Middle East Tech Univ Team

    2015-03-01

    We describe a novel method for excitation of Atomic Force Microscope (AFM) cantilevers by means of radiation pressure for imaging in an AFM for the first time. Piezo excitation is the most common method for cantilever excitation, but it may cause spurious resonance peaks. A fiber optic interferometer with 1310 nm laser was used both to measure the deflection of cantilever and apply a force to the cantilever in a LT-AFM/MFM from NanoMagnetics Instruments. The laser power was modulated at the cantilever`s resonance frequency by a digital Phase Lock Loop (PLL). The force exerted by the radiation pressure on a perfectly reflecting surface by a laser beam of power P is F = 2P/c. We typically modulate the laser beam by ~ 800 μW and obtain 10nm oscillation amplitude with Q ~ 8,000 at 2.5x10-4 mbar. The cantilever's stiffness can be accurately calibrated by using the radiation pressure. We have demonstrated performance of the radiation pressure excitation in AFM/MFM by imaging a hard disk sample between 4-300K and Abrikosov vortex lattice in BSCCO single crystal at 4K to for the first time.

  5. The children of parents exposed to atomic bombs: Estimates of the genetic doubling dose of radiation for humans

    SciTech Connect

    Neel, J.V.; Schull, W.J.; Awa, A.A.; Satoh, C.; Kato, H.; Otake, M.; Yoshimoto, Y. )

    1990-06-01

    The data collected in Hiroshima and Nagasaki during the past 40 years on the children of survivors of the atomic bombings and on the children of a suitable control population are analyzed on the basis of the newly revised estimates of radiation doses. No statistically significant effects emerge with respect to eight different indicators. Since, however, it may confidently be assumed some mutations were induced, we have taken the data at face value and calculated the minimal gametic doubling doses of acute radiation for the individual indicators at various probability levels. An effort has also been made to calculate the most probable doubling dose for the indicators combined. The latter value is between 1.7 and 2.2 Sv. It is suggested the appropriate figure for chronic radiation would be between 3.4 and 4.5 Sv. These estimates suggest humans are less sensitive to the genetic effects of radiation than has been assumed on the basis of past extrapolations from experiments with mice.

  6. The children of parents exposed to atomic bombs: estimates of the genetic doubling dose of radiation for humans.

    PubMed

    Neel, J V; Schull, W J; Awa, A A; Satoh, C; Kato, H; Otake, M; Yoshimoto, Y

    1990-06-01

    The data collected in Hiroshima and Nagasaki during the past 40 years on the children of survivors of the atomic bombings and on the children of a suitable control population are analyzed on the basis of the newly revised estimates of radiation doses. No statistically significant effects emerge with respect to eight different indicators. Since, however, it may confidently be assumed some mutations were induced, we have taken the data at face value and calculated the minimal gametic doubling doses of acute radiation for the individual indicators at various probability levels. An effort has also been made to calculate the most probable doubling dose for the indicators combined. The latter value is between 1.7 and 2.2 Sv. It is suggested the appropriate figure for chronic radiation would be between 3.4 and 4.5 Sv. These estimates suggest humans are less sensitive to the genetic effects of radiation than has been assumed on the basis of past extrapolations from experiments with mice.

  7. Atomic Resonance Radiation Energetics Investigation as a Diagnostic Method for Non-Equilibrium Hypervelocity Flows

    NASA Technical Reports Server (NTRS)

    Meyer, Scott A.; Bershader, Daniel; Sharma, Surendra P.; Deiwert, George S.

    1996-01-01

    Absorption measurements with a tunable vacuum ultraviolet light source have been proposed as a concentration diagnostic for atomic oxygen, and the viability of this technique is assessed in light of recent measurements. The instrumentation, as well as initial calibration measurements, have been reported previously. We report here additional calibration measurements performed to study the resonance broadening line shape for atomic oxygen. The application of this diagnostic is evaluated by considering the range of suitable test conditions and requirements, and by identifying issues that remain to be addressed.

  8. Photoionization and Velocity Map Imaging spectroscopy of atoms, molecules and clusters with Synchrotron and Free Electron Laser radiation at Elettra

    NASA Astrophysics Data System (ADS)

    Di Fraia, M.; Sergo, R.; Stebel, L.; Giuressi, D.; Cautero, G.; Tudor, M.; Callegari, C.; O'Keeffe, P.; Ovcharenko, Y.; Lyamayev, V.; Feyer, V.; Moise, A.; Devetta, M.; Piseri, P.; Grazioli, C.; Coreno, M.

    2015-12-01

    Advances in laser and Synchrotron Radiation instrumentation are continuously boosting fundamental research on the electronic structure of matter. At Elettra the collaboration between several groups active in the field of atomic, molecular and cluster physics and the Instrumentation and Detector Laboratory has resulted in an experimental set-up that successfully tackles the challenges posed by the investigation of the electronic structure of isolated species in the gas phase. The use of Synchrotron Radiation (SR) and Free Electron Laser (FEL) light, allows to cover a wide spectrum of targets from energetic to dynamics. We developed a Velocity Map Imaging (VMI) spectrometer that allows to perform as well SR as FEL experiments, just by changing part of the detection system. In SR experiments, at the Gasphase beamline of Elettra, a cross delay line detector is used, coupled to a 4-channel time-to-digital converter that reconstructs the position of the electrons. Simultaneously, a Time-of-Flight (TOF) mass spectrometer is used to acquire photoion spectra. Such a system allows PhotoElectron-PhotoIon-Coincidence (PEPICO) spectroscopy of atoms, molecules and clusters. In FEL experiments (notably differing from SR experiments in the much higher rate of events produced and detected, which forces one to forfeit coincidence detection), at the Low Density Matter (LDM) beamline of FERMI, a Micro Channel Plate (MCP) a phosphor screen and a CCD camera are used instead, capable of shot-by-shot collection of practically all events, albeit without time resolution.

  9. Evaluation of Thermal Control Coatings and Polymeric Materials Exposed to Ground Simulated Atomic Oxygen and Vacuum Ultraviolet Radiation

    NASA Technical Reports Server (NTRS)

    Kamenetzky, R. R.; Vaughn, J. A.; Finckenor, M. M.; Linton, R. C.

    1995-01-01

    Numerous thermal control and polymeric samples with potential International Space Station applications were evaluated for atomic oxygen and vacuum ultraviolet radiation effects in the Princeton Plasma Physics Laboratory 5 eV Neutral Atomic Oxygen Facility and in the MSFC Atomic Oxygen Drift Tube System. Included in this study were samples of various anodized aluminum samples, ceramic paints, polymeric materials, and beta cloth, a Teflon-impregnated fiberglass cloth. Aluminum anodizations tested were black duranodic, chromic acid anodize, and sulfuric acid anodize. Paint samples consisted of an inorganic glassy black paint and Z-93 white paint made with the original PS7 binder and the new K2130 binder. Polymeric samples evaluated included bulk Halar, bulk PEEK, and silverized FEP Teflon. Aluminized and nonaluminized Chemfab 250 beta cloth were also exposed. Samples were evaluated for changes in mass, thickness, solar absorptance, and infrared emittance. In addition to material effects, an investigation was made comparing diffuse reflectance/solar absorptance measurements made using a Beckman DK2 spectroreflectometer and like measurements made using an AZ Technology-developed laboratory portable spectroreflectometer.

  10. Tissue kerma vs distance relationships for initial nuclear radiation from the atomic devices detonated over Hiroshima and Nagasaki

    SciTech Connect

    Kerr, G.D.; Pace, J.V. III; Scott, W.H. Jr.

    1983-06-01

    Initial nuclear radiation is comprised of prompt neutrons and prompt primary gammas from an exploding nuclear device, prompt secondary gammas produced by neutron interactions in the environment, and delayed neutrons and delayed fission-product gammas from the fireball formed after the nuclear device explodes. These various components must all be considered in establishing tissue kerma vs distance relationships which describe the decrease of initial nuclear radiation with distance in Hiroshima and in Nagasaki. The tissue kerma at ground evel from delayed fission-product gammas and delayed neutrons was investigated using the NUIDEA code developed by Science Applications, Inc. This code incorporates very detailed models which can take into account such features as the rise of the fireball, the rapid radioactive decay of fission products in it, and the perturbation of the atmosphere by the explosion. Tissue kerma vs distance relationships obtained by summing results of these current state-of-the-art calculations will be discussed. Our results clearly show that the prompt secondary gammas and delayed fission-product gammas are the dominant components of total tissue kerma from initial nuclear radiation in the cases of the atomic (or pure-fission) devices detonated over Hiroshima and Nagasaki.

  11. Improved statistical determination of absolute neutrino masses via radiative emission of neutrino pairs from atoms

    NASA Astrophysics Data System (ADS)

    Zhang, Jue; Zhou, Shun

    2016-06-01

    The atomic transition from an excited state |e ⟩ to the ground state |g ⟩ by emitting a neutrino pair and a photon, i.e., |e ⟩→|g ⟩+|γ ⟩+|νi⟩+|ν¯j⟩ with i , j =1 , 2, 3, has been proposed by Yoshimura and his collaborators as an alternative way to determine the absolute scale m0 of neutrino masses. More recently, a statistical analysis of the fine structure of the photon spectrum from this atomic process has been performed [N. Song et al. Phys. Rev. D 93, 013020 (2016)] to quantitatively examine the experimental requirements for a realistic determination of absolute neutrino masses. In this paper, we show how to improve the statistical analysis and demonstrate that the previously required detection time can be reduced by one order of magnitude for the case of a 3 σ determination of m0˜0.01 eV with an accuracy better than 10%. Such an improvement is very encouraging for further investigations on measuring absolute neutrino masses through atomic processes.

  12. The carcinogenic risks of low-LET and high-LET ionizing radiations

    SciTech Connect

    Fabrikant, J.I. )

    1989-08-01

    New information is available concerning the carcinogenic effects of radiation and the implications for risk assessment and risk management. This information comes from further follow-up of the epidemiological studies of the Japanese atomic bomb survivors, patients irradiated medically for cancer and allied conditions, and workers exposed in various occupations. In the Japanese atomic bomb survivors the carcinogenic risks are estimated to be somewhat higher than previously, due to the reassessment of the atomic-bomb dosimetry, further follow-up with increase in the number of excess cancer deaths, particularly in survivors irradiated early in life, and changes in the methods of analysis to compute the age-specific risks of cancer. Because of the characteristics of the atomic bomb survivor series as regards sample size, age and sex distribution, duration for follow-up, person-years at risk, and type of dosimetry, the mortality experience of the atomic bomb survivors was selected by the UNSCEAR Committee and the BEIR V Committee as the more appropriate basis for projecting risk estimates for the general population. In the atomic bomb survivors, the dose-effect relationship for overall cancer mortality other than leukemia is consistent with linearity below 3 Gy, while the dose-effect relationship for leukemia, excluding chronic lymphatic leukemia, conforms best to a linear-quadratic function. The shape of the dose-incidence curve at low doses still remains uncertain, and the data do not rule out the possible existence of a threshold for an neoplasm. The excess relative risk of mortality from all cancers combined is estimated to be 1.39 per Gy (shielded kerma), which corresponds to an absolute risk of 10.0 excess cancer deaths per 10,000 PYGy; the relative risks is 1.41 at 1 Gy (organ-absorbed dose), and an absolute risk of 13.07 excess cancer deaths per 10,000 PYGy. 19 refs.

  13. Somatic cell mutations at the glycophorin A locus in erythrocytes of atomic bomb survivors: Implications for radiation carcinogenesis

    SciTech Connect

    Kyoizumi, Seishi; Akiyama, Mitoshi; Tanabe, Kazumi; Hirai, Yuko; Kusunoki, Yoichiro; Umeki, Shigeko

    1996-07-01

    To clarify the relationship between somatic cell mutations and radiation exposure, the frequency of hemizygous mutant erythrocytes at the glycophorin A (GPA) locus was measured by flow cytometry for 1,226 heterozygous atomic bomb (A-bomb) survivors in HIroshima and Nagasaki. For statistical analysis, both GPA mutant frequency and radiation dose were log-transformed to normalize skewed distributions of these variables. The GPA mutant frequency increased slightly but significantly with age at testing and with the number of cigarettes smoked. Also, mutant frequency was significantly higher in males than in females even with adjustment for smoking and was higher to Hiroshima than in Nagasaki. These characteristics of background GPA mutant frequency are qualitatively similar to those of background solid cancer incidence or mortality obtained from previous epidemiological studies of survivors. An analysis of the mutant frequency dose response using a descriptive model showed that the doubling dose is about 1.20 Sv [95% confidence interval (CI): 0.95-1.56], whereas the minimum dose for detecting a significant increase in mutant frequency is about 0.24 Sv (95% CI: 0.041-0.51). No significant effects of sex, city or age at the time of exposure on the dose response were detected. Interestingly, the doubling dose of the GPA mutant frequency was similar to that of solid cancer incidence in A-bomb survivors. This observation is in line with the hypothesis that radiation-induced somatic cell mutations are the major cause of excess cancer risk after radiation. 49 refs., 6 figs., 2 tabs.

  14. Atomic oxygen and ultraviolet radiation mission total exposures for LDEF experiments

    NASA Technical Reports Server (NTRS)

    Bourassa, R. J.; Gillis, J. R.; Rousslang, Ken W.

    1991-01-01

    An analytical treatment of the effect of thermal molecular velocity on spacecraft atomic oxygen (AO) flux is presented. The analysis leads to a closed form equation that incorporates the effect of atmospheric temperature, number density, spacecraft velocity, and incidence angle on AO flux. The effects of atmospheric rotation, solar activity, and geomagnetic index on AO flux are also included on the computer model. Data developed with the model are presented for the Long Duration Exposure Facility (LDEF). The results incorporate variations in the defining environmental and orbital parameters of the spacecraft over its six year orbital flight. Cumulative ultraviolet solar and albedo exposures were calculated .

  15. Allowing for random errors in radiation dose estimates for the atomic bomb survivor data.

    PubMed

    Pierce, D A; Stram, D O; Vaeth, M

    1990-09-01

    The presence of random errors in the individual radiation dose estimates for the A-bomb survivors causes underestimation of radiation effects in dose-response analyses, and also distorts the shape of dose-response curves. Statistical methods are presented which will adjust for these biases, provided that a valid statistical model for the dose estimation errors is used. Emphasis is on clarifying some rather subtle statistical issues. For most of this development the distinction between radiation dose and exposure is not critical. The proposed methods involve downward adjustment of dose estimates, but this does not imply that the dosimetry system is faulty. Rather, this is a part of the dose-response analysis required to remove biases in the risk estimates. The primary focus of this report is on linear dose-response models, but methods for linear-quadratic models are also considered briefly. Some plausible models for the dose estimation errors are considered, which have typical errors in a range of 30-40% of the true values, and sensitivity analysis of the resulting bias corrections is provided. It is found that for these error models the resulting estimates of excess cancer risk based on linear models are about 6-17% greater than estimates that make no allowance for dose estimation errors. This increase in risk estimates is reduced to about 4-11% if, as has often been done recently, survivors with dose estimates above 4 Gy are eliminated from the analysis.

  16. Effects of radiation on the longitudinal trends of total serum cholesterol levels in the atomic bomb survivors.

    PubMed

    Wong, F L; Yamada, M; Sasaki, H; Kodama, K; Hosoda, Y

    1999-06-01

    The effects of radiation on the long-term trends of the total serum cholesterol levels of the Hiroshima and Nagasaki atomic bomb survivors were examined using data collected in the Adult Health Study over a 28-year period (1958-1986). The growth-curve method was used to model the longitudinal age-dependent changes in cholesterol levels. For each sex, temporal trends of cholesterol levels were characterized with respect to age, body mass index, city and birth year. We then examined whether the temporal trends differed by radiation dose. We showed that the mean growth curve of cholesterol levels for the irradiated subjects were significantly higher than that for the unirradiated subjects, and that the increase was greater for women than for men. No difference in dose response was detected between Hiroshima and Nagasaki. An increased mean level of cholesterol was evident for irradiated women in general, but a notable increase was apparent in males only for the youngest birth cohort of 1935-1945. The difference in the mean cholesterol levels between the irradiated and unirradiated subjects diminished past 70 years of age. It is not known whether this is due to natural progression or is an artifact of nonrandom variation in the rate of participation in the examinations. The maximum predicted increase at 1 Gy for women occurred at age 52 years for the 1930 cohort: 2.5 mg/dl (95% CI 1.6-3.3 mg/dl) for Hiroshima and 2.3 mg/dl (95% CI 1.5-3.1 mg/dl) for Nagasaki. The corresponding increase for men occurred at age 29 years for the 1940 cohort: 1.6 mg/dl (95% CI 0.4-2.8) for Hiroshima and 1.4 mg/dl (95% CI 0.3-2.6) for Nagasaki. Controlling for cigarette smoking did not alter the dose-response relationship. Although the difference in the mean growth curves of the irradiated and unirradiated groups was statistically significant, there was a considerable overlap in the individual growth curves of the two groups. The significant sex difference and the greater magnitude of

  17. Computational modeling of alloys at the atomic scale: from ab initio and thermodynamics to radiation-induced heterogeneous precipitation

    SciTech Connect

    Caro, A; Caro, M; Klaver, P; Sadigh, B; Lopasso, E M; Srivilliputhur, S G

    2007-02-02

    We describe the path we are following in the development of a computational approach to simulate radiation damage in FeCr ferritic steels. In these alloys magnetism introduces an anomaly in the heat of formation of the solid solution that has implications on the way excess Cr precipitates in the {alpha}{prime} phase in presence of heterogeneities. These complexities represent a challenge for atomistic (empirical) approaches that we address: (i) by proposing a modified many body potential, (ii) by using a thermodynamic package that determines free energy and phase diagrams, and (iii) by using a displacement Monte Carlo code in the transmutation ensemble that can deal with millions of atoms in parallel computational environments. This approach predicts that grain boundaries, dislocations and free surfaces are not preferential sites for precipitation of {alpha}{prime}.

  18. The investigation of the light radiation caused polyethylene based materials deterioration by means of atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Sikora, A.; Grabarek, A.; Moroń, L.; Wałecki, M.; Kryla, P.

    2016-02-01

    The impact of the environmental conditions on the materials used in various devices and constructions, in particular in electrotechnical applications, has an critical impact in terms of their reliability and utilization range in specific climatic conditions. Due to increasing utilitarian requirements, technological processes complexity and introducing new materials (for instance nanomaterials), advanced diagnostic techniques are desired. One of such techniques is atomic force microscopy (AFM), which allows to study the changes of the roughness and mechanical properties of the surface at the submicrometer scale, enabling the investigation of the degradation processes. In this work the deterioration of selected group of polyethylene based materials have been measured by means of AFM, as the samples were exposed to the simulated solar light and UV-C radiation. Such an analysis of the environmental conditions impact on the deterioration process using AFM methods for various versions of specific material was not presented before.

  19. Calculation of radiation attenuation coefficients, effective atomic numbers and electron densities for some building materials.

    PubMed

    Damla, N; Baltas, H; Celik, A; Kiris, E; Cevik, U

    2012-07-01

    Some building materials, regularly used in Turkey, such as sand, cement, gas concrete (lightweight, aerated concrete), tile and brick, have been investigated in terms of mass attenuation coefficient (μ/ρ), effective atomic, numbers (Z(eff)), effective electron densities (N(e)) and photon interaction cross section (σ(a)) at 14 different energies from 81- to 1332-keV gamma-ray energies. The gamma rays were detected by using gamma-ray spectroscopy, a High Purity Germanium (HPGe) detector. The elemental compositions of samples were analysed using an energy dispersive X-ray fluorescence spectrometer. Mass attenuation coefficients of these samples have been compared with tabulations based upon the results of WinXcom. The theoretical mass attenuation coefficients were estimated using the mixture rule and the experimental values of investigated parameters were compared with the calculated values. The agreement of measured values of mass attenuation coefficient, effective atomic numbers, effective electron densities and photon interaction cross section with the theory has been found to be quite satisfactory. PMID:22128356

  20. Liver cancer in atomic-bomb survivors: histological characteristics and relationships to radiation and hepatitis B and C viruses.

    PubMed

    Fukuhara, T; Sharp, G B; Mizuno, T; Itakura, H; Yamamoto, M; Tokunaga, M; Tokuoka, S; Cologne, J B; Fujita, Y; Soda, M; Mabuchi, K

    2001-06-01

    Histological features of primary liver cancer among atomic-bomb survivors and their relationship to hepatitis B (HBV) and C viral (HCV) infections are of special interest because of the increased risk of liver cancer in persons exposed to ionizing radiation and the high and increasing liver cancer rates in Japan and elsewhere. We conducted a pathology review of liver cancers occurring from 1958 to 1987 among subjects in the 120,321 member cohort of 1945 Hiroshima and Nagasaki residents. A panel of pathologists classified tumor histological types and defined accompanying cirrhotic changes of the liver. Archival tissue samples were assessed for HBV using pathology stains and PCR. Reverse transcriptase (RT) PCR was used to determine HCV status. We used unconditional logistic regression to compare 302 hepatocellular carcinoma (HCC) cases to 53 cholangiocarcinoma (CC) cases, adjusting for age, year of diagnosis, sex and viral status. Cirrhotic changes occurred significantly more often among HCC than CC cases (76% in HCC and 6% in CC). Compared to CC cases, HCC cases were 10.9 times more likely to be HBV-positive (95% confidence interval: 2.1-83.2) and 4.3 times more likely to be HCV-positive (95% confidence interval: 1.1-20.5). No significant differences were found between HCC and CC cases in radiation exposures. The predominance of HCC in the atomic-bomb survivors follows the background liver cancer pattern in Japan. Our findings suggest that HBV and HCV are involved in the pathogenesis of HCC with or without cirrhosis and are significantly less important in that of CC.

  1. Ionization of sodium and rubidium nS, nP, and nD Rydberg atoms by blackbody radiation

    SciTech Connect

    Beterov, I. I.; Tretyakov, D. B.; Ryabtsev, I. I.; Ekers, A.; Bezuglov, N. N.

    2007-05-15

    Results of theoretical calculations of ionization rates of Rb and Na Rydberg atoms by blackbody radiation (BBR) are presented. Calculations have been performed for nS, nP, and nD states of Na and Rb, which are commonly used in a variety of experiments, at principal quantum numbers n=8-65 and at three ambient temperatures of 77, 300, and 600 K. A peculiarity of our calculations is that we take into account the contributions of BBR-induced redistribution of population between Rydberg states prior to photoionization and field ionization by extraction electric field pulses. The obtained results show that these phenomena affect both the magnitude of measured ionization rates and shapes of their dependences on n. The calculated ionization rates are compared with the results of our earlier measurements of BBR-induced ionization rates of Na nS and nD Rydberg states with n=8-20 at 300 K. A good agreement for all states except nS with n>15 is observed. We also present the useful analytical formulas for the quick estimation of BBR ionization rates of Rydberg atoms.

  2. On the role of atomic metastability in the production of Balmer line radiation from ‘cold’ atomic hydrogen, deuterium and hydrogenic ion impurities in fusion edge plasmas

    NASA Astrophysics Data System (ADS)

    Hey, J. D.

    2012-03-01

    Published arguments, which assign an important role to atomic metastability in the production of ‘narrow’ Zeeman component radiation from the boundary region of fusion plasmas, are examined critically in relation to l-redistribution by proton and electron collisions, and mixing of unperturbed atomic states by the ion microfield and microfield gradient. It is concluded that these important processes indeed severely constrain the contribution from ‘metastable’ states to the generation of the hydrogen Balmer spectra, for electron concentrations above 1012 cm-3, as pointed out before by the present author (Hey et al 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3555). The analysis of collision-induced l-redistribution represents an extension of that used previously (Hey et al 1996 Contrib. Plasma Phys. 36 583), applicable up to higher electron densities. For comparison purposes, we also consider the question of metastability of ionized helium in a low-temperature plasma, and that of some common hydrogenic impurities (C5+ and Ne9+) in a hydrogen (deuterium) fusion plasma. While for low nuclear charge Z the metastability of 2s1/2 levels is quenched by the plasma environment, it is much reduced in high-Z ions owing to the rapid increase with Z of the two-photon electric dipole (2E1) and magnetic dipole (M1) spontaneous transition rates to the ground state, whereas the role of the plasma in these cases is less important. The main new principle elaborated in this work is the sensitivity of atomic line strengths, and hence collision strengths, to perturbation by the plasma environment for transitions between fine-structure sublevels of the same principal quantum number. As the plasma microfield strength grows, ‘allowed’ transitions diminish in strength, while ‘forbidden’ transitions grow. However, owing to violation of the parity selection rule, there is an overall loss of collision strength available to transitions, resulting from the appearance of significant

  3. Solar cell radiation response near the interface of different atomic number materials

    NASA Technical Reports Server (NTRS)

    Burke, E. A.; Cappelli, J. R.; Lowe, L. F.; Wall, J. A.

    1972-01-01

    The response of cobalt 60 irradiated N/P silicon solar cells was measured as a function of the atomic number of the medium adjacent to the cell and the direction of the gamma ray beam. The interpositioning of various thicknesses of aluminum between the adjacent material and the cell had the effect of moving the cell to various locations in an approximate monatomic numbered medium. Using this technique the solar cell response was determined at various distances from the interface for gold and beryllium. The results were compared with predictions based upon ionization chamber measurements of dose perturbations in aluminum and found to agree within five percent. Ionization chamber data was then used to estimate the influence of various base contact materials.

  4. Effects of atomic radiation: A half-century of studies from Hiroshima and Nagasaki

    SciTech Connect

    Schull, W.J.

    1996-11-01

    This is a notable book. For the first time, a thoroughly experienced scientist has undertaken, as the author says, {open_quotes}to present the atomic bomb survivor story in all its complexity,{close_quotes} and to aid the reader, Prof. Schull has eschewed the use of technical terms. Where this could not be done, he has defined them in the text or the glossary. The task could only have been done by someone like Prof. Schull, who in various capacities has been involved in the Japanese studies since 1949. The book therefore is not a conventional epidemiological monograph. It is addressed to both the professional and nonprofessional reader, and it includes various elements of biology; it deals with history as well as science; and it considers some of its material as in a personal essay. This is an ambitious, difficult and useful undertaking that provides much information; its writing, however, is not always quite direct and incisive.

  5. Radiation amplification near an autoionizing state: A model in atomic Ca

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Lambropoulos, P.; Tang, X.

    1994-08-01

    A consistent treatment of a AWoI through an autoionizing state with a solid quantitative application to Ca was presented. The treatment, in addition to the inclusion of a realistic and quantitative description of the significant atomic configuration, was also self-consistent in the sense that a complete specification of the pumping was included. In this study, it was demonstrated that multiphoton pumping can furnish a realistic scheme of amplification with or without inversion close to the minimum of an autoionizing state within the framework of an internally constant formalism. The gain for a probe pulse of a suitable duration was achieved based on the realistic parameters and a time-dependent analysis. One general indication observed was, within a particular range of intensities, ionization loss decreases up to a certain extent with increasing intensity.

  6. Relationship of five anthropometric measurements at age 18 to radiation dose among atomic bomb survivors exposed in utero

    SciTech Connect

    Nakashima, Eiji )

    1994-04-01

    Five body measurements-standing height, body weight, sitting height, chest circumference and intercristal diameter-of 18-year-old atomic bomb survivors exposed in utero in Hiroshima and Nagasaki were analyzed in relation to DS86 uterine dose. Age in utero was divided into four periods: 0-7, 8-15, 16-25 and [>=]26 weeks. This categorization is based upon the study of radiation-induced brain damage. The linear regression analyses for these five variables showed significant decreases with increasing dose. The regression coefficients were -2.65 cm/Gy for standing height, -2.46 kg/Gy for body weight, -0.92 cm/Gy for sitting height, -1.37 cm/Gy for chest circumference and -0.32 cm/Gy for intercristal diameter. The multivariate test statistic for the overall dose effect on five body measurements was significant, but the interaction between dose and gestational period was not significant. Principal-component analysis was applied to the five variables. For the first-component scores, the dose effect was significant, but the interaction between dose and gestational period was not significant. For the second-component scores, the dose effect was significant specifically at 0.7 weeks. The radiation dose effect on the second principal component found at 0-7 weeks of gestation suggests that malformation occur in this period. 17 refs., 2 figs., 4 tabs.

  7. Late effects of radiation on the human immune system: an overview of immune response among the atomic-bomb survivors.

    PubMed

    Akiyama, M

    1995-11-01

    The studies of the late effects of atomic-bomb (A-bomb) radiation on the immune system were started about 20 years after the bombings in 1945. The most remarkable late effects of radiation are the functional and quantitative abnormalities of T and B cells in survivors exposed to high doses (> or = 1.0 Gy). Abnormalities of T-cell immunity include (1) a decreased proportion of CD3+ T cells in peripheral blood lymphocytes, particularly the proportion of CD4+ CD45RA+ naive T cells (study period 1987-91); (2) an increased frequency of CD4- and CD8- (double negative) alpha beta + T cells (1987-91); and (3) functional defects in T-cell responses to mitogens and alloantigens (1974-85). B-cell abnormalities include: (1) a significant increase in the proportion of B cells among peripheral lymphocytes (1987-91); (2) an increase in serum immunoglobulin A levels in females and immunoglobulin M and the incidence of rheumatoid factor in both sexes (1987-89); and (3) an increased level of anti-Epstein-Barr virus antibody titer (1987-90). In contrast, suggestive (0.05 < p < 0.1) or not significant (p > 0.1) dose effects were observed for the number and function of natural killer cells (1983-91), and benign monoclonal gammopathy (1979-87). In addition, studies initiated sooner after the bombing such as the incidence of autoimmune diseases (1958-87), systemic bacterial infections (1954-67), and granulocyte functions (1947-79) also show little dose-effects. Thus, A-bomb radiation induced the alteration of the balance/interaction between the T- and B-cell subsets--specifically, a decrease in the T-cell population and an increase in the B-cell population in the periphery.

  8. Analysis of chromosome aberrations in atomic bomb survivors for dose assessment: studies at the Radiation Effects Research Foundation from 1968 to 1993.

    PubMed

    Awa, A

    1997-01-01

    Exposure to ionizing radiation causes damage to living cells, especially to DNA in the cell nucleus. The degree of this cellular damage depends on the amount of radiation administered. This review discusses current findings concerning radiation-induced chromosome aberrations that were produced in 1945 and that can still be observed in the somatic cells of atomic bomb survivors in Hiroshima and Nagasaki. The scoring methods of G-banding and fluorescence in situ hybridization are compared. In addition, some findings concerning chromosomal aberrations in citizens of the former Soviet Union affected by the Chernobyl accident are presented.

  9. Progress in the Use of Isotopes: The Atomic Triad - Reactors, Radioisotopes and Radiation

    DOE R&D Accomplishments Database

    Libby, W. F.

    1958-08-04

    Recent years have seen a substantial growth in the use of isotopes in medicine, agriculture, and industry: up to the minute information on the production and use of isotopes in the U.S. is presented. The application of radioisotopes to industrial processes and manufacturing operations has expanded more rapidly than any one except its most ardent advocates expected. New uses and new users are numerous. The adoption by industry of low level counting techniques which make possible the use of carbon-14 and tritium in the control of industrial processes and in certain exploratory and research problems is perhaps most promising of current developments. The latest information on savings to industry will be presented. The medical application of isotopes has continued to develop at a rapid pace. The current trend appears to be in the direction of improvements in technique and the substitution of more effective isotopes for those presently in use. Potential and actual benefits accruing from the use of isotopes in agriculture are reviewed. The various methods of production of radioisotopes are discussed. Not only the present methods but also interesting new possibilities are covered. Although isotopes are but one of the many peaceful uses of the atom, it is the first to pay its way. (auth)

  10. Half-cycle-like field-enhanced harmonic radiation by femtosecond laser-atom interaction

    NASA Astrophysics Data System (ADS)

    Yu, Cheng-Xin; Liu, Shi-Bing; Song, Hai-Ying

    2013-06-01

    A manipulatable half-cycle-like field (HCLF), homochromy with the driving femtosecond laser, is applied to enhance the harmonic emission by optimizing their relative delay time. We find that, by numerical computation, the HCLF can deliver a substantial momentum to the accelerated electrons as they return to their parent ions by a suitable phase delay, and also significantly increase the atomic ionization rate supplementarily. The results show that the harmonic order of the maximum or cut-off photon energy emitted in the presence of a half-cycle manipulating light pulse is risen to the 177th order, which is a significant increase compared with the 53rd order harmonics in the case of a single driving light pulse. To understand the essence from the wave-packet kinetics of the return electrons and their relation to the harmonic emission, we utilize the phase-space analysis of the coordinate momentum of an electronic wave packet by using a Gabor transformation, by which the presented numerical conclusions are further confirmed.

  11. Use of radiation effects for a controlled change in the chemical composition and properties of materials by intentional addition or substitution of atoms of a certain kind

    SciTech Connect

    Gurovich, B. A.; Prikhod'ko, K. E. Kuleshova, E. A.; Maslakov, K. I.; Komarov, D. A.

    2013-06-15

    This study is a continuation of works [1-12] dealing with the field developed by the authors, namely, to widen the possibilities of radiation methods for a controlled change in the atomic composition and properties of thin-film materials. The effects under study serve as the basis for the following two methods: selective atom binding and selective atom substitution. Such changes in the atomic composition are induced by irradiation by mixed beams consisting of protons and other ions, the energy of which is sufficient for target atom displacements. The obtained experimental data demonstrate that the changes in the chemical composition of thin-film materials during irradiation by an ion beam of a complex composition take place according to mechanisms that differ radically from the well-known mechanisms controlling the corresponding chemical reactions in these materials. These radical changes are shown to be mainly caused by the accelerated ioninduced atomic displacements in an irradiated material during irradiation; that is, they have a purely radiation nature. The possibilities of the new methods for creating composite structures consisting of regions with a locally changed chemical composition and properties are demonstrated for a wide class of materials.

  12. Generation of tunable coherent far-infrared radiation using atomic Rydberg states

    SciTech Connect

    Bookless, W.

    1980-12-01

    A source of tunable far-infrared radiation has been constructed. The system has been operated at 91.6 cm/sup -1/ with a demonstrated tunability of .63 cm/sup -1/. The system is based on a Rydberg state transition in optically pumped potassium vapor. The transition energy is tuned by the application of an electric field to the excited vapor. The transition wavelength and the shifted wavelength were detected and measured by the use of a Michelson interferometer and a liquid helium cooled Ga:Ge bolometer and the data was reduced using Fast Fourier transform techniques. Extensive spectroscopy was done on the potassium vapor to elucidate the depopulation paths and rates of the excited levels. Both theoretical and experimental results are presented to support the conclusions of the research effort. Additionally, possible alternative approaches to the population of the excited state are explored and recommendations are made for the future development of this source as well as the potential uses of it in molecular spectroscopy.

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

    NASA Technical Reports Server (NTRS)

    Singh, G.

    1973-01-01

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

  14. Atomic data generation and collisional radiative modeling of argon II, argon III, and neon I for laboratory and astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Munoz Burgos, Jorge Manuel

    Accurate knowledge of atomic processes plays a key role in modeling the emission in laboratory as well as in astrophysical plasmas. These processes are included in a collisional-radiative model and the results are compared with experimental measurements for Ar and Ne ions from the ASTRAL (Auburn Steady sTate Research fAciLity) experiment. The accuracy of our model depends upon the quality of the atomic data we use. Atomic data for near neutral systems present a challenge due to the low accuracy of perturbative methods for these systems. In order to improve our model we rely on non-perturbative methods such as R - Matrix and RMPS ( R -Matrix with Pseudo-States) to include correlation in the collision cross-sections. In the case of Ar + we compared R -Matrix electron-impact excitation data against the results from a new RMPS calculation. The aim was to assess the effects of continuum-coupling effects on the atomic data and the resulting spectrum. We do our spectral modeling using the ADAS suite of codes. Our collisional-radiative formalism assumes that the excited levels are in quasi- static equilibrium with the ground and metastable populations. In our model we allow for N e and T e variation along the line of sight by fitting our densities and temperature profiles with those measured within the experiment. The best results so far have been obtained by the fitting of the experimental temperature and density profiles with Gaussian and polynomial distribution functions. The line of sight effects were found to have a significant effect on the emission modeling. The relative emission rates were measured in the ASTRAL helicon plasma source. A spectrometer which features a 0.33 m Criss-Cross Scanning monochromator and a CCD camera is used for this study. ASTRAL produces bright intense Ar and Ne plasmas with n e = 10 11 to 10 13 cm -3 and T e = 2 to 10 eV. A series of 7 large coils produce an axial magnetic field up to 1.3 kGauss. A fractional helix antenna is used to

  15. Atomic data generation and collisional radiative modeling of argon II, argon III, and neon I for laboratory and astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Munoz Burgos, Jorge Manuel

    Accurate knowledge of atomic processes plays a key role in modeling the emission in laboratory as well as in astrophysical plasmas. These processes are included in a collisional-radiative model and the results are compared with experimental measurements for Ar and Ne ions from the ASTRAL (Auburn Steady sTate Research fAciLity) experiment. The accuracy of our model depends upon the quality of the atomic data we use. Atomic data for near neutral systems present a challenge due to the low accuracy of perturbative methods for these systems. In order to improve our model we rely on non-perturbative methods such as R - Matrix and RMPS ( R -Matrix with Pseudo-States) to include correlation in the collision cross-sections. In the case of Ar + we compared R -Matrix electron-impact excitation data against the results from a new RMPS calculation. The aim was to assess the effects of continuum-coupling effects on the atomic data and the resulting spectrum. We do our spectral modeling using the ADAS suite of codes. Our collisional-radiative formalism assumes that the excited levels are in quasi- static equilibrium with the ground and metastable populations. In our model we allow for N e and T e variation along the line of sight by fitting our densities and temperature profiles with those measured within the experiment. The best results so far have been obtained by the fitting of the experimental temperature and density profiles with Gaussian and polynomial distribution functions. The line of sight effects were found to have a significant effect on the emission modeling. The relative emission rates were measured in the ASTRAL helicon plasma source. A spectrometer which features a 0.33 m Criss-Cross Scanning monochromator and a CCD camera is used for this study. ASTRAL produces bright intense Ar and Ne plasmas with n e = 10 11 to 10 13 cm -3 and T e = 2 to 10 eV. A series of 7 large coils produce an axial magnetic field up to 1.3 kGauss. A fractional helix antenna is used to

  16. Lack of effects of atomic bomb radiation on genetic instability of tandem-repetitive elements in human germ cells

    SciTech Connect

    Kodaira, Mieko; Satoh, Chiyoko; Hiyama, Keiko |

    1995-12-01

    In a pilot study to detect the potential effects of atomic bomb radiation on germ-line instability, we screened 64 children from 50 exposed families and 60 from 50 control families for mutations at six minisatellite loci by using Southern blot analysis with Pc-1, {lambda}TM-18, ChdTC-15, p{lambda}g3, {lambda}MS-1, and CEB-1 probes. In the exposed families, one or both parents received a radiation dose >0.01 Sv. Among the 64 children, only one child had parents who were both exposed. Thus, of a total of 128 gametes that produced the 64 children, 65 gametes were derived from exposed parents and 63 were from unexposed parents, the latter being included in a group of 183 unexposed gametes used for calculating mutation rates. The average parental gonadal dose for the 65 gametes was 1.9 Sv. We detected a total of 28 mutations at the p{lambda}g3, {lambda}MS-1, and CEB-1 loci, but no mutations at the Pc-1, {lambda}TM-18, and ChdTC-15 loci. We detected 6 mutations in 390 alleles of the 65 exposed gametes and 22 mutations in 1098 alleles of the 183 gametes from the unexposed parents. The mean mutation rate per locus per gamete in these six minisatellite loci was 1.5% in the exposed parents and 2.0% in the unexposed parents. We observed no significant difference in mutation rates in the children of the exposed and the unexposed parents (P = .37, Fisher`s exact probability test). 38 refs., 1 fig., 5 tabs.

  17. The SIBERIA dedicated synchrotron radiation source: status report on the storage rings complex at the Kurchatov Institute for Atomic Energy

    NASA Astrophysics Data System (ADS)

    Artemiev, A. N.; Akhmedzhanov, S. M.; Vasilyev, A. A.; Gritsuk, G. M.; Dozorov, A. V.; Doronkin, Yu. V.; Zabelin, A. V.; Klimenko, M. N.; Kotov, S. A.; Krylov, Yu. V.; Lebedev, V. A.; Lipilin, A. V.; Nagornyh, I. M.; Nikulin, O. N.; Odintsov, D. G.; Pashkov, S. D.; Pesterev, S. G.; Prosvetov, V. K.; Rybakov, V. N.; Samorukov, M. M.; Treshchin, V. A.; Ushkov, V. L.; Tsup, A. R.; Chaikin, E. M.; Yupinov, Yu. L.

    1991-10-01

    This paper reviews the status of the SIBERIA storage rings complex. The parameters of the linac, booster synchrotron and main ring are given. The transfer of the SIBERIA-1 storage ring to its new site is described. The main parameters of the engineering systems for the SIBERIA complex are presented. The assembly of the SIBERIA-2 storage ring is planned to be finished in 1991. The SIBERIA storage rings complex has been constructed at the Kurchatov Institute for Atomic Energy (IAE) and is the first dedicated synchrotron radiation source in the USSR. The facility includes the SIBERIA-1 450 MeV electron storage ring, the SIBERIA-2 2.5 GeV electron storage ring, two electron transport lines EOC-1 and EOC-2, and an 80-100 MeV electron linac which serves as the injector. The general layout of SIBERIA is shown in fig. 1. All accelerators of the SIBERIA facility are designed and manufactured at the Institute of Nuclear Physics (INP) at Novosibirsk.

  18. The grave is wide: the Hibakusha of Hiroshima and Nagasaki and the legacy of the Atomic Bomb Casualty Commission and the Radiation Effects Research Foundation.

    PubMed

    O'Malley, Gerald F

    2016-07-01

    Following the atomic bomb attacks on Japan in 1945, scientists from the United States and Japan joined together to study the Hibakusha - the bomb affected people in what was advertised as a bipartisan and cooperative effort. In reality, despite the best efforts of some very dedicated and earnest scientists, the early years of the collaboration were characterized by political friction, censorship, controversy, tension, hostility, and racism. The 70-year history, scientific output and cultural impact of the Atomic Bomb Casualty Commission and the Radiation Effects Research Foundation are described in the context of the development of Occupied Japan.

  19. The grave is wide: the Hibakusha of Hiroshima and Nagasaki and the legacy of the Atomic Bomb Casualty Commission and the Radiation Effects Research Foundation.

    PubMed

    O'Malley, Gerald F

    2016-07-01

    Following the atomic bomb attacks on Japan in 1945, scientists from the United States and Japan joined together to study the Hibakusha - the bomb affected people in what was advertised as a bipartisan and cooperative effort. In reality, despite the best efforts of some very dedicated and earnest scientists, the early years of the collaboration were characterized by political friction, censorship, controversy, tension, hostility, and racism. The 70-year history, scientific output and cultural impact of the Atomic Bomb Casualty Commission and the Radiation Effects Research Foundation are described in the context of the development of Occupied Japan. PMID:27158765

  20. Cancer and non-cancer effects in Japanese atomic bomb survivors.

    PubMed

    Little, M P

    2009-06-01

    The survivors of the atomic bombings in Hiroshima and Nagasaki are a general population of all ages and sexes and, because of the wide and well characterised range of doses received, have been used by many scientific committees (International Commission on Radiological Protection (ICRP), United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), Biological Effects of Ionizing Radiations (BEIR)) as the basis of population cancer risk estimates following radiation exposure. Leukaemia was the first cancer to be associated with atomic bomb radiation exposure, with preliminary indications of an excess among the survivors within the first five years after the bombings. An excess of solid cancers became apparent approximately ten years after radiation exposure. With increasing follow-up, excess risks of most cancer types have been observed, the major exceptions being chronic lymphocytic leukaemia, and pancreatic, prostate and uterine cancer. For most solid cancer sites a linear dose response is observed, although in the latest follow-up of the mortality data there is evidence (p = 0.10) for an upward curvature in the dose response for all solid cancers. The only cancer sites which exhibit (upward) curvature in the dose response are leukaemia, and non-melanoma skin and bone cancer. For leukaemia the dose response is very markedly upward curving, indeed largely describable as a pure quadratic dose response, particularly in the low dose (0-2 Sv) range. Even 55 years after the bombings over 40% of the Life Span Study cohort remain alive, so continued follow-up of this group is vital for completing our understanding of long-term radiation effects in people. In general, the relative risks per unit dose among the Japanese atomic bomb survivors are greater than those among comparable subsets in studies of medically exposed individuals. Cell sterilisation largely accounts for the discrepancy in relative risks between these two populations, although other

  1. Workshop Report on Atomic Bomb Dosimetry--Review of Dose Related Factors for the Evaluation of Exposures to Residual Radiation at Hiroshima and Nagasaki.

    PubMed

    Kerr, George D; Egbert, Stephen D; Al-Nabulsi, Isaf; Bailiff, Ian K; Beck, Harold L; Belukha, Irina G; Cockayne, John E; Cullings, Harry M; Eckerman, Keith F; Granovskaya, Evgeniya; Grant, Eric J; Hoshi, Masaharu; Kaul, Dean C; Kryuchkov, Victor; Mannis, Daniel; Ohtaki, Megu; Otani, Keiko; Shinkarev, Sergey; Simon, Steven L; Spriggs, Gregory D; Stepanenko, Valeriy F; Stricklin, Daniela; Weiss, Joseph F; Weitz, Ronald L; Woda, Clemens; Worthington, Patricia R; Yamamoto, Keiko; Young, Robert W

    2015-12-01

    Groups of Japanese and American scientists, supported by international collaborators, have worked for many years to ensure the accuracy of the radiation dosimetry used in studies of health effects in the Japanese atomic bomb survivors. Reliable dosimetric models and systems are especially critical to epidemiologic studies of this population because of their importance in the development of worldwide radiation protection standards. While dosimetry systems, such as Dosimetry System 1986 (DS86) and Dosimetry System 2002 (DS02), have improved, the research groups that developed them were unable to propose or confirm an additional contribution by residual radiation to the survivor's total body dose. In recognition of the need for an up-to-date review of residual radiation exposures in Hiroshima and Nagasaki, a half-day technical session was held for reports on newer studies at the 59 th Annual HPS Meeting in 2014 in Baltimore, MD. A day-and-a-half workshop was also held to provide time for detailed discussion of the newer studies and to evaluate their potential use in clarifying the residual radiation exposure to atomic bomb survivors at Hiroshima and Nagasaki. The process also involved a re-examination of very early surveys of radioisotope emissions from ground surfaces at Hiroshima and Nagasaki and early reports of health effects. New insights were reported on the potential contribution to residual radiation from neutron-activated radionuclides in the airburst's dust stem and pedestal and in unlofted soil, as well as from fission products and weapon debris from the nuclear cloud. However, disparate views remain concerning the actual residual radiation doses received by the atomic bomb survivors at different distances from the hypocenter. The workshop discussion indicated that measurements made using thermal luminescence and optically stimulated luminescence, like earlier measurements, especially in very thin layers of the samples, could be expanded to detect possible

  2. Workshop Report on Atomic Bomb Dosimetry--Review of Dose Related Factors for the Evaluation of Exposures to Residual Radiation at Hiroshima and Nagasaki.

    PubMed

    Kerr, George D; Egbert, Stephen D; Al-Nabulsi, Isaf; Bailiff, Ian K; Beck, Harold L; Belukha, Irina G; Cockayne, John E; Cullings, Harry M; Eckerman, Keith F; Granovskaya, Evgeniya; Grant, Eric J; Hoshi, Masaharu; Kaul, Dean C; Kryuchkov, Victor; Mannis, Daniel; Ohtaki, Megu; Otani, Keiko; Shinkarev, Sergey; Simon, Steven L; Spriggs, Gregory D; Stepanenko, Valeriy F; Stricklin, Daniela; Weiss, Joseph F; Weitz, Ronald L; Woda, Clemens; Worthington, Patricia R; Yamamoto, Keiko; Young, Robert W

    2015-12-01

    Groups of Japanese and American scientists, supported by international collaborators, have worked for many years to ensure the accuracy of the radiation dosimetry used in studies of health effects in the Japanese atomic bomb survivors. Reliable dosimetric models and systems are especially critical to epidemiologic studies of this population because of their importance in the development of worldwide radiation protection standards. While dosimetry systems, such as Dosimetry System 1986 (DS86) and Dosimetry System 2002 (DS02), have improved, the research groups that developed them were unable to propose or confirm an additional contribution by residual radiation to the survivor's total body dose. In recognition of the need for an up-to-date review of residual radiation exposures in Hiroshima and Nagasaki, a half-day technical session was held for reports on newer studies at the 59 th Annual HPS Meeting in 2014 in Baltimore, MD. A day-and-a-half workshop was also held to provide time for detailed discussion of the newer studies and to evaluate their potential use in clarifying the residual radiation exposure to atomic bomb survivors at Hiroshima and Nagasaki. The process also involved a re-examination of very early surveys of radioisotope emissions from ground surfaces at Hiroshima and Nagasaki and early reports of health effects. New insights were reported on the potential contribution to residual radiation from neutron-activated radionuclides in the airburst's dust stem and pedestal and in unlofted soil, as well as from fission products and weapon debris from the nuclear cloud. However, disparate views remain concerning the actual residual radiation doses received by the atomic bomb survivors at different distances from the hypocenter. The workshop discussion indicated that measurements made using thermal luminescence and optically stimulated luminescence, like earlier measurements, especially in very thin layers of the samples, could be expanded to detect possible

  3. Radiation exposure to marine biota around the Fukushima Daiichi NPP.

    PubMed

    Keum, Dong-Kwon; Kim, Byeong-Ho; Lim, Kwang-Muk; Choi, Yong-Ho

    2014-05-01

    The dose rates for six marine organisms, pelagic fish, benthic fish, mollusks, crustaceans, macroalgae, and polychaete worms, representative in marine ecosystems, have been predicted by the equilibrium model with the measured seawater activity concentrations at three locations around the Fukushima Daiich nuclear power plant after the accident on March 11, 2011. Model prediction showed that total dose rates for the biota in the costal sea reached 4.8E4 μGy/d for pelagic fish, 3.6E6 μGy/d for crustaceans, 3.8E6 μGy/d for benthic fish, 5.2E6 μGy/d for macroalgae, 6.6E6 μGy/d for mollusks, and 8.0E6 μGy/d for polychaete worms. The predicted total dose rates remained above the UNSCEAR's (United Nations Scientific Committee on the Effect of Atomic Radiation) benchmark level (1.0E4 μGy/d for an individual aquatic organism), for only the initial short period, which seems to be insufficiently long to bring about any detrimental effect on the marine biota at the population level. Furthermore, the total dose rates for benthic fish and crustaceans approximated using the measured activity concentration of the biota and bottom sediment was well below the benchmark level. From these results, it may be concluded that the impact of the ionizing radiation on the marine biota around the Fukushima NPP as a consequence of the accident would be insignificant. PMID:24374805

  4. Matrix-isolation studies on the radiation-induced chemistry in H₂O/CO₂ systems: reactions of oxygen atoms and formation of HOCO radical.

    PubMed

    Ryazantsev, Sergey V; Feldman, Vladimir I

    2015-03-19

    The radiation-induced transformations occurring upon X-ray irradiation of solid CO2/H2O/Ng systems (Ng = Ar, Kr, Xe) at 8-10 K and subsequent annealing up to 45 K were studied by Fourier transform infrared spectroscopy. The infrared (IR) spectra of deposited matrices revealed the presence of isolated monomers, dimers, and intermolecular H2O···CO2 complexes. Irradiation resulted in effective decomposition of matrix-isolated carbon dioxide and water yielding CO molecules and OH radicals, respectively. Annealing of the irradiated samples led to formation of O3, HO2, and a number of xenon hydrides of HXeY type (in the case of xenon matrices). The formation of these species was used for monitoring of the postirradiation thermally induced chemical reactions involving O and H atoms generated by radiolysis. It was shown that the radiolysis of CO2 in noble-gas matrices produced high yields of stabilized oxygen atoms. In all cases, the temperatures at which O atoms become mobile and react are lower than those of H atoms. Dynamics and reactivity of oxygen atoms was found to be independent of the precursor nature. In addition, the formation of HOCO radicals was observed in all the noble-gas matrices at remarkably low temperatures. The IR spectra of HOCO and DOCO were first characterized in krypton and xenon matrices. It was concluded that the formation of HOCO was mainly due to the radiation-induced evolution of the weakly bound H2O···CO2 complexes. This result indicates the significance of weak intermolecular interactions in the radiation-induced chemical processes in inert low-temperature media.

  5. Matrix-isolation studies on the radiation-induced chemistry in H₂O/CO₂ systems: reactions of oxygen atoms and formation of HOCO radical.

    PubMed

    Ryazantsev, Sergey V; Feldman, Vladimir I

    2015-03-19

    The radiation-induced transformations occurring upon X-ray irradiation of solid CO2/H2O/Ng systems (Ng = Ar, Kr, Xe) at 8-10 K and subsequent annealing up to 45 K were studied by Fourier transform infrared spectroscopy. The infrared (IR) spectra of deposited matrices revealed the presence of isolated monomers, dimers, and intermolecular H2O···CO2 complexes. Irradiation resulted in effective decomposition of matrix-isolated carbon dioxide and water yielding CO molecules and OH radicals, respectively. Annealing of the irradiated samples led to formation of O3, HO2, and a number of xenon hydrides of HXeY type (in the case of xenon matrices). The formation of these species was used for monitoring of the postirradiation thermally induced chemical reactions involving O and H atoms generated by radiolysis. It was shown that the radiolysis of CO2 in noble-gas matrices produced high yields of stabilized oxygen atoms. In all cases, the temperatures at which O atoms become mobile and react are lower than those of H atoms. Dynamics and reactivity of oxygen atoms was found to be independent of the precursor nature. In addition, the formation of HOCO radicals was observed in all the noble-gas matrices at remarkably low temperatures. The IR spectra of HOCO and DOCO were first characterized in krypton and xenon matrices. It was concluded that the formation of HOCO was mainly due to the radiation-induced evolution of the weakly bound H2O···CO2 complexes. This result indicates the significance of weak intermolecular interactions in the radiation-induced chemical processes in inert low-temperature media. PMID:25469518

  6. Effective atomic numbers and electron densities of some human tissues and dosimetric materials for mean energies of various radiation sources relevant to radiotherapy and medical applications

    NASA Astrophysics Data System (ADS)

    Kurudirek, Murat

    2014-09-01

    Effective atomic numbers, Zeff, and electron densities, neff, are convenient parameters used to characterise the radiation response of a multi-element material in many technical and medical applications. Accurate values of these physical parameters provide essential data in medical physics. In the present study, the effective atomic numbers and electron densities have been calculated for some human tissues and dosimetric materials such as Adipose Tissue (ICRU-44), Bone Cortical (ICRU-44), Brain Grey/White Matter (ICRU-44), Breast Tissue (ICRU-44), Lung Tissue (ICRU-44), Soft Tissue (ICRU-44), LiF TLD-100H, TLD-100, Water, Borosilicate Glass, PAG (Gel Dosimeter), Fricke (Gel Dosimeter) and OSL (Aluminium Oxide) using mean photon energies, Em, of various radiation sources. The used radiation sources are Pd-103, Tc-99, Ra-226, I-131, Ir-192, Co-60, 30 kVp, 40 kVp, 50 kVp (Intrabeam, Carl Zeiss Meditec) and 6 MV (Mohan-6 MV) sources. The Em values were then used to calculate Zeff and neff of the tissues and dosimetric materials for various radiation sources. Different calculation methods for Zeff such as the direct method, the interpolation method and Auto-Zeff computer program were used and agreements and disagreements between the used methods have been presented and discussed. It has been observed that at higher Em values agreement is quite satisfactory (Dif.<5%) between the adopted methods.

  7. Long-term radiation-related health effects in a unique human population: lessons learned from the atomic bomb survivors of Hiroshima and Nagasaki.

    PubMed

    Douple, Evan B; Mabuchi, Kiyohiko; Cullings, Harry M; Preston, Dale L; Kodama, Kazunori; Shimizu, Yukiko; Fujiwara, Saeko; Shore, Roy E

    2011-03-01

    For 63 years scientists in the Atomic Bomb Casualty Commission and its successor, the Radiation Effects Research Foundation, have been assessing the long-term health effects in the survivors of the atomic bombings of Hiroshima and Nagasaki and in their children. The identification and follow-up of a large population (approximately a total of 200,000, of whom more than 40% are alive today) that includes a broad range of ages and radiation exposure doses, and healthy representatives of both sexes; establishment of well-defined cohorts whose members have been studied longitudinally, including some with biennial health examinations and a high survivor-participation rate; and careful reconstructions of individual radiation doses have resulted in reliable excess relative risk estimates for radiation-related health effects, including cancer and noncancer effects in humans, for the benefit of the survivors and for all humankind. This article reviews those risk estimates and summarizes what has been learned from this historic and unique study.

  8. Long-term Radiation-Related Health Effects in a Unique Human Population: Lessons Learned from the Atomic Bomb Survivors of Hiroshima and Nagasaki

    PubMed Central

    Douple, Evan B.; Mabuchi, Kiyohiko; Cullings, Harry M.; Preston, Dale L.; Kodama, Kazunori; Shimizu, Yukiko; Fujiwara, Saeko; Shore, Roy E.

    2014-01-01

    For 63 years scientists in the Atomic Bomb Casualty Commission and its successor, the Radiation Effects Research Foundation, have been assessing the long-term health effects in the survivors of the atomic bombings of Hiroshima and Nagasaki and in their children. The identification and follow-up of a large population (approximately a total of 200 000, of whom more than 40% are alive today) that includes a broad range of ages and radiation exposure doses, and healthy representatives of both sexes; establishment of well-defined cohorts whose members have been studied longitudinally, including some with biennial health examinations and a high survivor participation rate; and careful reconstructions of individual radiation doses have resulted in reliable excess relative risk estimates for radiation-related health effects, including cancer and noncancer effects in humans, for the benefit of the survivors and for all humankind. This article reviews those risk estimates and summarizes what has been learned from this historic and unique study. PMID:21402804

  9. Long-term radiation-related health effects in a unique human population: lessons learned from the atomic bomb survivors of Hiroshima and Nagasaki.

    PubMed

    Douple, Evan B; Mabuchi, Kiyohiko; Cullings, Harry M; Preston, Dale L; Kodama, Kazunori; Shimizu, Yukiko; Fujiwara, Saeko; Shore, Roy E

    2011-03-01

    For 63 years scientists in the Atomic Bomb Casualty Commission and its successor, the Radiation Effects Research Foundation, have been assessing the long-term health effects in the survivors of the atomic bombings of Hiroshima and Nagasaki and in their children. The identification and follow-up of a large population (approximately a total of 200,000, of whom more than 40% are alive today) that includes a broad range of ages and radiation exposure doses, and healthy representatives of both sexes; establishment of well-defined cohorts whose members have been studied longitudinally, including some with biennial health examinations and a high survivor-participation rate; and careful reconstructions of individual radiation doses have resulted in reliable excess relative risk estimates for radiation-related health effects, including cancer and noncancer effects in humans, for the benefit of the survivors and for all humankind. This article reviews those risk estimates and summarizes what has been learned from this historic and unique study. PMID:21402804

  10. Atom-atom inelastic collisions and three-body atomic recombination in weakly ionized argon plasmas

    NASA Technical Reports Server (NTRS)

    Braun, C. G.; Kunc, J. A.

    1989-01-01

    A stationary collisional-radiative model including both inelastic electron-atom and atom-atom collisions is used to examine nonequilibrium weakly ionized argon plasmas with atomic densities 10 to the 16th to 10 to the 20th/cu cm, temperatures below 6000 K, and with different degrees of radiation trapping. It is shown that three-body atomic recombination becomes important at high particle densities. Comparison is made between the present approach and Thomson's theory for atomic recombination.

  11. Ionization of nS, nP, and nD lithium, potassium, and cesium Rydberg atoms by blackbody radiation

    SciTech Connect

    Beterov, I. I. Ryabtsev, I. I.; Tretyakov, D. B.; Bezuglov, N. N.; Ekers, A.

    2008-07-15

    The results of theoretical calculations of the blackbody ionization rates of lithium, potassium, and cesium atoms residing in Rydberg states are presented. The calculations are performed for nS, nP, and nD states in a wide range of principal quantum numbers, n = 8-65, for blackbody radiation temperatures T = 77, 300, and 600 K. The calculations are performed using the known quasi-classical formulas for the photoionization cross sections and for the radial matrix elements of transitions in the discrete spectrum. The effect of the blackbody-radiation-induced population redistribution between Rydberg states on the blackbody ionization rates measured under laboratory conditions is quantitatively analyzed. Simple analytical formulas that approximate the numerical results and that can be used to estimate the blackbody ionization rates of Rydberg atoms are presented. For the S series of lithium, the rate of population of high-lying Rydberg levels by blackbody radiation is found to anomalously behave as a function of n. This anomaly is similar to the occurrence of the Cooper minimum in the discrete spectrum.

  12. Lung cancer susceptibility among atomic bomb survivors in relation to CA repeat number polymorphism of epidermal growth factor receptor gene and radiation dose.

    PubMed

    Yoshida, Kengo; Nakachi, Kei; Imai, Kazue; Cologne, John B; Niwa, Yasuharu; Kusunoki, Yoichiro; Hayashi, Tomonori

    2009-12-01

    Lung cancer is a leading cause of cancer death worldwide. Prevention could be improved by identifying susceptible individuals as well as improving understanding of interactions between genes and etiological environmental agents, including radiation exposure. The epidermal growth factor receptor (EGFR)-signaling pathway, regulating cellular radiation sensitivity, is an oncogenic cascade involved in lung cancer, especially adenocarcinoma. The cytosine adenine (CA) repeat number polymorphism in the first intron of EGFR has been shown to be inversely correlated with EGFR production. It is hypothesized that CA repeat number may modulate individual susceptibility to lung cancer. Thus, we carried out a case-cohort study within the Japanese atomic bomb (A-bomb) survivor cohort to evaluate a possible association of CA repeat polymorphism with lung cancer risk in radiation-exposed or negligibly exposed (<5 mGy) A-bomb survivors. First, by dividing study subjects into Short and Long genotypes, defined as the summed CA repeat number of two alleles < or = 37 and > or = 38, respectively, we found that the Short genotype was significantly associated with an increased risk of lung cancer, specifically adenocarcinoma, among negligibly exposed subjects. Next, we found that prior radiation exposure significantly enhanced lung cancer risk of survivors with the Long genotype, whereas the risk for the Short genotype did not show any significant increase with radiation dose, resulting in indistinguishable risks between these genotypes at a high radiation dose. Our findings imply that the EGFR pathway plays a crucial role in assessing individual susceptibility to lung adenocarcinoma in relation to radiation exposure.

  13. Lung cancer susceptibility among atomic bomb survivors in relation to CA repeat number polymorphism of epidermal growth factor receptor gene and radiation dose.

    PubMed

    Yoshida, Kengo; Nakachi, Kei; Imai, Kazue; Cologne, John B; Niwa, Yasuharu; Kusunoki, Yoichiro; Hayashi, Tomonori

    2009-12-01

    Lung cancer is a leading cause of cancer death worldwide. Prevention could be improved by identifying susceptible individuals as well as improving understanding of interactions between genes and etiological environmental agents, including radiation exposure. The epidermal growth factor receptor (EGFR)-signaling pathway, regulating cellular radiation sensitivity, is an oncogenic cascade involved in lung cancer, especially adenocarcinoma. The cytosine adenine (CA) repeat number polymorphism in the first intron of EGFR has been shown to be inversely correlated with EGFR production. It is hypothesized that CA repeat number may modulate individual susceptibility to lung cancer. Thus, we carried out a case-cohort study within the Japanese atomic bomb (A-bomb) survivor cohort to evaluate a possible association of CA repeat polymorphism with lung cancer risk in radiation-exposed or negligibly exposed (<5 mGy) A-bomb survivors. First, by dividing study subjects into Short and Long genotypes, defined as the summed CA repeat number of two alleles < or = 37 and > or = 38, respectively, we found that the Short genotype was significantly associated with an increased risk of lung cancer, specifically adenocarcinoma, among negligibly exposed subjects. Next, we found that prior radiation exposure significantly enhanced lung cancer risk of survivors with the Long genotype, whereas the risk for the Short genotype did not show any significant increase with radiation dose, resulting in indistinguishable risks between these genotypes at a high radiation dose. Our findings imply that the EGFR pathway plays a crucial role in assessing individual susceptibility to lung adenocarcinoma in relation to radiation exposure. PMID:19843645

  14. PHYSICAL BASIS OF QUANTUM ELECTRONICS: Properties of spontaneous radiation of an atom located near a cluster of two spherical nanoparticles

    NASA Astrophysics Data System (ADS)

    Guzatov, D. V.; Klimov, Vasilii V.

    2005-10-01

    The analytic solution of the problem of spontaneous decay of an atom near a cluster of two perfectly conducting nanospheres is found. It is shown that spontaneous decay rates can considerably decrease or increase depending on the system geometry. In particular, within the framework of our model, the decay rate of an atom located between closely spaced spheres and having the transition dipole moment directed along the symmetry axis can be arbitrarily high.

  15. Modeling of neutrals in the Linac4 H(-) ion source plasma: hydrogen atom production density profile and Hα intensity by collisional radiative model.

    PubMed

    Yamamoto, T; Shibata, T; Ohta, M; Yasumoto, M; Nishida, K; Hatayama, A; Mattei, S; Lettry, J; Sawada, K; Fantz, U

    2014-02-01

    To control the H(0) atom production profile in the H(-) ion sources is one of the important issues for the efficient and uniform surface H(-) production. The purpose of this study is to construct a collisional radiative (CR) model to calculate the effective production rate of H(0) atoms from H2 molecules in the model geometry of the radio-frequency (RF) H(-) ion source for Linac4 accelerator. In order to validate the CR model by comparison with the experimental results from the optical emission spectroscopy, it is also necessary for the model to calculate Balmer photon emission rate in the source. As a basic test of the model, the time evolutions of H(0) production and the Balmer Hα photon emission rate are calculated for given electron energy distribution functions in the Linac4 RF H(-) ion source. Reasonable test results are obtained and basis for the detailed comparisons with experimental results have been established. PMID:24593558

  16. Measurements of Radiation Near An Atomic Spectral Line From the Interaction of a 30-GeV Electron Beam And a Long Plasma

    SciTech Connect

    Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W.P.; Assmann, R.; Decker, F.J.; Hogan, M.J.; Iverson, R.; Siemann, R.H.; Walz, D.; Whittum, D.; Blue, B.; Clayton, C.; Joshi, C.; Marsh, K.A.; Mori, W.B.; Wang, S.; Katsouleas, T.; Lee, S.; Muggli, P.; /Southern California U.

    2005-09-12

    Emissions produced or initiated by a 30 GeV electron beam propagating through a {approx}1 m long heat pipe oven containing neutral and partially ionized vapor have been measured near atomic spectral lines in a beam-plasma wakefield experiment. The Cerenkov spatial profile has been studied as a function of oven temperature and pressure, observation wavelength, and ionizing laser intensity and delay. The Cerenkov peak angle is affected by the creation of plasma; estimates of plasma and neutral density have been extracted. Increases in visible background radiation consistent with increased plasma recombination emissions due to dissipation of wakefields were simultaneously measured.

  17. Measurements of radiation near an atomic spectral line from the interaction of a 30 GeV electron beam and a long plasma

    SciTech Connect

    Catravas, P.E.; Chattopadhyay, S.; Esarey, E.; Leemans, W.P.; Assmann, R.; Decker, F.-J.; Hogan, M.J.; Iverson, R.; Siemann, R.H.; Walz, D.; Whittum, D.; Blue, B.; Clayton, C; Joshi, C.; Marsh, K.A.; Mori, W.B.; Wang, S.; Katsouleas, T.; Lee, S.; Muggli, P.

    2000-10-31

    Emissions produced or initiated by a 30 GeV electron beam propagating through a {approx} 1 m long heat pipe oven containing neutral and partially ionized vapor have been measured near atomic spectral lines in a beam-plasma wakefield experiment. The Cerenkov spatial profile has been studied as a function of oven temperature and pressure, observation wavelength, and ionizing laser intensity and delay. The Cerenkov peak angle is affected by the creating of plasma, and estimates of neutral and plasma density have been extracted. Increases in visible background radiation, consistent with increased plasma recombination emissions due to dissipation of wakefields, were simultaneously measured.

  18. Surface modification of Sylgard 184 polydimethylsiloxane by 254 nm excimer radiation and characterization by contact angle goniometry, infrared spectroscopy, atomic force and scanning electron microscopy

    NASA Astrophysics Data System (ADS)

    Waddell, Emanuel A.; Shreeves, Stephen; Carrell, Holly; Perry, Christopher; Reid, Branden A.; McKee, James

    2008-06-01

    The modification of polydimethylsiloxane (PDMS) by narrow band 254 nm excimer radiation under a nitrogen atmosphere was characterized by contact angle goniometry, attenuated total reflectance infrared spectroscopy, atomic force and scanning electron microscopy. UV irradiation results in the formation of the carboxylic acids that influences the wettability of the surface. Continued exposure results in the formation of an inorganic surface (SiO x (1 < x < 2)) which hinders the ability to continually increase the wettability. The continuity of this inorganic layer is disrupted by the formation of surface cracks. These results have implications in the fabrication and chemical modification of microfluidic or micro-electro-mechanical systems.

  19. Velocity diffusion and radiation trapping force in a one-dimensional expansion of cold atomic clouds in a magneto-optical trap

    SciTech Connect

    Pradhan, S.; Mayya, Y. S.; Jagatap, B. N.

    2007-09-15

    We experimentally investigate one-dimensional (1D) expansion of a cold cloud of cesium atoms in orthogonal 2D configuration of near resonant laser beams by temporally modulating a pair of counterpropagating trapping beams of a magneto-optical trap (MOT). The cloud is observed to undergo ballistic expansion followed by superballistic explosive growth due to the fluctuations of the 2D radiation force. A model based on the theory of Brownian motion is developed and a comparison of experiments with theory is shown to provide a direct measure of the velocity diffusion coefficient. We also observe sudden contraction of the cloud immediately after switching off the pair of trapping beams, which provides direct evidence for the existence of the radiation trapping force in a MOT.

  20. Polarization of Lyman-Alpha Radiation from Atomic Hydrogen Excited by Electron Impact form Near Threshold to 1800 eV

    NASA Technical Reports Server (NTRS)

    James, G. K.; Slevin, J. A.; Dziczek, D.; McConkey, J. W.; Bray, Igor

    1998-01-01

    The polarization of Lyman-a radiation, produced by electron-impact excitation of atomic hydrogen, has been measured over the extended energy range from near threshold to 1800 eV. Measurements were obtained in a crossed-beam experiment using a silica-reflection linear polarization analyzer in tandem with a vacuum-ultraviolet monochromator to isolate the emitted line radiation. Comparison with various theoretical calculations shows that the present experimental results are in good agreement with theory over the entire range of electron-impact energies and, in particular, are in excellent agreement with theoretical convergent-close-coupling (CCC) calculations performed in the present work. Our polarization data are significantly different from the previous experimental measurements of Ott, Kauppila, and Fite.

  1. Evaluation of a direct-current argon plasma as a primary pseudocontinuum radiation source for wavelength-modulated atomic absorption spectrometry

    SciTech Connect

    Messman, J.D.; O'Haver, T.C.; Epstein, M.S.

    1985-02-01

    A direct-current argon plasma (DCP) pseudocontinuum source is investigated as an alternative to a Cermax xenon arc continuum lamp (XAL) for wavelength-modulated continuum-source atomic absorption spectrometry (WM-AAC), particularly for the determination of elements in the lower ultraviolet wavelength region. The emission line from the DCP source is intentionally broadened by aspirating a large concentration of analyte solution into the plasma so that it appears as pseudocontinuum radiation over the narrow wavelength modulation interval. The DCP source significantly reduces both order overlap and far stray radiation compared to the XAL, but signal-to-noise ratios are degraded relative to the XAL source because of plasma-emission self-reversal flicker noise. 27 references, 3 figures, 4 tables.

  2. Radiation

    NASA Video Gallery

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  3. Quantum-mechanical calculation of three-dimensional atom-diatom collisions in the presence of intense laser radiation

    NASA Technical Reports Server (NTRS)

    Devries, P. L.; George, T. F.

    1979-01-01

    A formalism is presented for describing the collision of fluorine with the hydrogen molecule in the presence of intense radiation. For a laser frequency on the order of the spin-orbit splitting of fluorine, the interaction of the molecular system with the radiation occurs at relatively long range where, for this system, the electric dipole is vanishingly small. Hence the interaction occurs due to the magnetic dipole coupling. Even so, at low collision energies a substantial enhancement of the quenching cross section is found for a radiation intensity of 10 to the 11th W/sq cm.

  4. Radiation effects analysis in a group of interventional radiologists using biological and physical dosimetry methods.

    PubMed

    Ramos, M; Montoro, A; Almonacid, M; Ferrer, S; Barquinero, J F; Tortosa, R; Verdú, G; Rodríguez, P; Barrios, L L; Villaescusa, J I

    2010-08-01

    Interventional radiologists and staff members are frequently exposed to protracted and fractionated low doses of ionizing radiation, which extend during all their professional activities. These exposures can derive, due to the effects of direct and scattered radiation, in deterministic effects (radiodermitis, aged skin, cataracts, telangiectasia in nasal region, vasocellular epitelioms, hands depilation) and/or stochastic ones (cancer incidence). A methodology has been proposed for estimating the radiation risk or detriment from a group of six exposed interventional radiologists of the Hospital Universitario La Fe (Valencia, Spain), which had developed general exposition symptoms attributable to deterministic effects of ionizing radiation. Equivalent doses have been periodically registered using TLD's and wrist dosimeters, H(p)(10) and H(p)(0.07), respectively, and estimated through the observation of translocations in lymphocytes of peripheral blood (biological methods), by extrapolating the yield of translocations to their respective dose-effect curves. The software RADRISK has been applied for estimating radiation risks in these occupational radiation exposures. This software is based on transport models from epidemiological studies of population exposed to external sources of ionizing radiation, such as Hiroshima and Nagasaki atomic bomb survivors [UNSCEAR, Sources and effects of ionizing radiation: 2006 report to the general assembly, with scientific annexes. New York: United Nations; 2006]. The minimum and maximum average excess ratio for skin cancer has been, using wrist physical doses, of [1.03x10(-3), 5.06x10(-2)], concluding that there is not an increased risk of skin cancer incidence. The minimum and maximum average excess ratio for leukemia has been, using TLD physical doses, of [7.84x10(-2), 3.36x10(-1)], and using biological doses, of [1.40x10(-1), 1.51], which is considerably higher than incidence rates, showing an excess radio-induced risk of

  5. The effects of internal radiation exposure on cancer mortality in nuclear workers at Rocketdyne/Atomics International.

    PubMed Central

    Ritz, B; Morgenstern, H; Crawford-Brown, D; Young, B

    2000-01-01

    We examined the effects of chronic exposure to radionuclides, primarily uranium and mixed-fission products, on cancer mortality in a retrospective cohort study of workers enrolled in the radiation-monitoring program of a nuclear research and development facility. Between 1950 and 1994, 2,297 workers were monitored for internal radiation exposures, and 441 workers died, 134 (30.4%) of them from cancer as the underlying cause. We calculated internal lung-dose estimates based on urinalysis and whole-body and lung counts reported for individual workers. We examined cancer mortality of workers exposed at different cumulative lung-dose levels using complete risk-set analysis for cohort data, adjusting for age, pay type, time since first radiation monitored, and external radiation. In addition, we examined the potential for confounding due to chemical exposures and smoking, explored whether external radiation exposure modifies the effects of internal exposure, and estimated effects after excluding exposures likely to have been unrelated to disease onset. Dose-response relations were observed for death from hemato- and lymphopoietic cancers and from upper aerodigestive tract cancers, adjusting for age, time since first monitored, pay type, and external (gamma) radiation dose. No association was found for other cancers, including cancers of the lung. Despite the small number of exposed deaths from specific cancer types and possible bias due to measurement error and confounding, the positive findings and strong dose-response gradients observed suggest carcinogenic effects of internal radiation to the upper aerodigestive tract and the blood and lymph system in this occupational cohort. However, causal inferences require replication of our results in other populations or confirmation with an extended follow-up of this cohort. PMID:10964795

  6. Non-local-thermodynamical-equilibrium effects in the x-ray emission of radiatively heated materials of different atomic numbers

    NASA Astrophysics Data System (ADS)

    Földes, I. B.; Eidmann, K.; Veres, G.; Bakos, J. S.; Witte, K.

    2001-07-01

    X-ray self-emission of radiatively heated materials with different values of Z has been investigated. Thin foils were uniformly heated by a 120-eV Hohlraum radiation of 400-ps duration in order to study the self-emission of a homogeneous, optically thin material. The x-ray emission spectra were followed for more than 2 ns. The spectrally integrated emission shows not only a strong Z dependence, but different temporal behaviors for different values of Z. The lower is the value of Z of the x-ray heated matter, the longer is the duration of self-emission. Theoretical comparison with a hydrocode and FLY post-processing shows a non-local-thermal equilibrium behavior caused by direct photoionization due to the thermal pumping radiation, which has a higher brightness temperature than the matter temperature of the heated material.

  7. Comparison of theory with atomic oxygen 130.4 nm radiation data from the Bow Shock ultraviolet 2 rocket flight

    NASA Technical Reports Server (NTRS)

    Levin, Deborah A.; Candler, Graham V.; Collins, Robert J.; Howlett, Carl L.; Espy, Patrick; Whiting, Ellis; Park, Chul

    1993-01-01

    Comparison is made between the results obtained from a state-of-the-art flow and radiative model and bow shock vacuum ultraviolet (VUV) data obtained the recent Bow Shock 2 Flight Experiment. An extensive data set was obtained from onboard rocket measurements at a reentry speed of 5 km/sec between the altitudes of approximately 65-85 km. A description of the NO photoionization cell used, the data, and the interpretation of the data will be presented. The primary purpose of the analyses is to assess the utility of the data and to propose a radiation model appropriate to the flight conditions of Bow Shock 2. Theoretical predictions based on flow modeling discussed in earlier work and a new radiation model are compared with data.

  8. Current Trends in Atomic Spectroscopy.

    ERIC Educational Resources Information Center

    Wynne, James J.

    1983-01-01

    Atomic spectroscopy is the study of atoms/ions through their interaction with electromagnetic radiation, in particular, interactions in which radiation is absorbed or emitted with an internal rearrangement of the atom's electrons. Discusses nature of this field, its status and future, and how it is applied to other areas of physics. (JN)

  9. Atomic Particle Detection, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Hellman, Hal

    This booklet is one of the booklets in the "Understanding the Atom Series" published by the U. S. Atomic Energy Commission for high school science teachers and their students. The instruments used to detect both particles and electromagnetic radiation that emerge from the nucleus are described. The counters reviewed include ionization chambers,…

  10. Radiation of Sound Waves Via Soliton Excitation of the Angarmonic Chain of Atoms in a Dislocation Core

    NASA Astrophysics Data System (ADS)

    Gestrin, S. G.; Shchukina, E. V.

    2016-07-01

    It is demonstrated that propagation of the soliton described by the Boussinesq equation along a linear defect of the crystal structure leads to radiation of sound waves (analog of the Vavilov-Cherenkov effect). Radiation that has a continuous spectrum diverges conically from the dislocation line, and the apex angle of the cone is determined by the ratio of the sound speed in the crystal to the soliton speed. With increasing soliton speed, the maximum of the spectral flux density of sound energy is displaced toward higher frequencies. An analytical expression for energy losses is derived.

  11. Free-free absorption of infrared radiation in collisions of electrons with neutral rare-gas atoms

    NASA Technical Reports Server (NTRS)

    Stallcop, J. R.

    1974-01-01

    A relationship between the inverse bremsstrahlung absorption cross section and the electron neutral momentum transfer cross section has been utilized to determine the infrared free-free continuum absorption coefficient for the negative ions of helium, neon, argon, krypton, and xenon. The values of the momentum transfer cross section for this calculation have been obtained from experimental measurements. Analytical expressions for the absorption coefficient have also been developed. From the results of this calculation, it is possible to determine the absorption coefficient per unit electron density per neutral atom for temperatures in the range from 2500 to 25,000 K. The results are compared with those from tabulations of previous calculations and those computed from theoretical values of the phase shifts for the elastic scattering of electrons by neutral atoms.

  12. Natural ionizing radiation exposure of the Spanish population.

    PubMed

    García-Talavera, M; Matarranz, J L; Martínez, M; Salas, R; Ramos, L

    2007-01-01

    This study investigates the exposure of the Spanish population to natural radiation sources. The annual average effective dose is estimated to be 1.6 mSv, taking into account contributions from cosmic radiation (18%), terrestrial gamma radiation (30%), radon and thoron inhalation (34%) and ingestion (18%). Cosmic radiation doses were calculated from town altitude data. Terrestrial gamma ray exposure outdoors were derived from the MARNA (natural gamma radiation map of Spain); indoor exposure was obtained multiplying the corresponding outdoor value by an experimentally calculated conversion factor. Radon doses were estimated from national surveys carried out throughout the country. To assess doses by ingestion, data from a detailed study on consumption habits in Spain and average radioactivity values from UNSCEAR have been considered. The variability in the exposures among individuals in the population has been explicitly taken into account in the assessment.

  13. Radiation May Indirectly Impair Growth Resulting in Reduced Standing Height via Subclinical Inflammation in Atomic-Bomb Survivors Exposed at Young Ages

    DOE PAGES

    Nakashima, Eiji; Neriishi, Kazuo; Hsu, Wan-Ling

    2015-01-01

    For youngmore » atomic-bomb (A-bomb) survivors, A-bomb radiation’s (total) effect on standing height is thought to comprise the sum of direct effect and indirect effect via inflammation. With the data of five inflammatory markers—white blood cell count, sialic acid, corrected erythrocyte sedimentation rate (ESR), α 1 globulin, and α 2 globulin—obtained in adulthood during the period 1988 to 1992, a summary inflammatory index was constructed as a surrogate for the five subclinical inflammatory markers. For 3,327 A-bomb survivors exposed at ages of less than 25 years, a structural equation model was analyzed to measure direct radiation effects on adult height as well as mediating effect of radiation via inflammation on the height after adjustment for other risk factors, smoking, cancer, inflammatory disease, obesity, and diabetes mellitus. The mediation proportion of the radiation effect on height via inflammation was approximately 5% for both sexes for all ages, and indirect dose effects via inflammation were statistically significant for both sexes combined and for females exposed at ages 0 to 5 years. Indirect dose effects for all ages via sialic acid, corrected ESR, and α 2 globulin were marginally significant for both sexes combined and for females. These proportions are likely underestimated.« less

  14. On the relationship between radiation-stimulated photoluminescence and nitrogen atoms in p-4 H-SiC

    NASA Astrophysics Data System (ADS)

    Lebedev, A. A.; Ber, B. Ya.; Bogdanova, E. V.; Seredova, N. V.; Kazantsev, D. Yu.; Kozlovski, V. V.

    2015-12-01

    Photoluminescence (PL) appearing in p-4 H-SiC upon its electron irradiation has been studied. A model that accounts for the dependence of the PL intensity on the irradiation dose is suggested. The conclusion is drawn that nitrogen-radiation defect donor-acceptor pairs are PL activators.

  15. Generation of undamped stokes radiation under resonant pumping of the dipole-forbidden transition in a {Xi}-atom

    SciTech Connect

    Kochanov, V. P.

    2009-12-15

    We have developed a theory of the nonlinear ring interaction of three intense fields in the scheme of resonant Raman scattering on the dipole-allowed transition from the ground state to the first excited state of a cascade three-level quantum system. We show that the backward Stokes radiation generated by a pump resonant to the dipole-forbidden transition can be used in remote laser sensing of metal vapors.

  16. Excitation of sodium D-line radiation in collisions of sodium atoms with internally excited H2, D2 and N2.

    NASA Technical Reports Server (NTRS)

    Krause, H. F.; Fricke, J.; Fite, W. L.

    1972-01-01

    Excitation of D-line radiation in collisions of Na atoms with vibrationally excited N2, H2, and D2 was studied in two modulated crossed-beam experiments. In both experiments, the molecular excitation was provided by heating the molecular beam to temperatures which were assumed to give populations corresponding to the Boltzmann distribution. In the first experiment, a total rate coefficient was measured as a function of molecular beam temperature. The second experiment achieved partial separation of internal vs kinetic energy transfer effects by using a velocity-selected molecular beam. The data from both experiments were used to determine parameters for the dependence of the transfer cross section upon the kinetic energy for a given change in the vibrational quantum number. Results indicate that most of the Na excitation energy comes from internal vibrational energy, with the remainder coming from kinetic energy.

  17. Spin-orbit and rotational couplings in radiative association of C({sup 3}P) and N({sup 4}S) atoms

    SciTech Connect

    Antipov, Sergey V.; Gustafsson, Magnus; Nyman, Gunnar

    2011-11-14

    The role of spin-orbit and rotational couplings in radiative association of C({sup 3}P) and N({sup 4}S) atoms is investigated. Couplings among doublet electronic states of the CN radical are considered, giving rise to a 6-state model of the process. The solution of the dynamical problem is based on the L{sup 2} method, where a complex absorbing potential is added to the Hamiltonian operator in order to treat continuum and bound levels in the same manner. Comparison of the energy-dependent rate coefficients calculated with and without spin-orbit and rotational couplings shows that the couplings have a strong effect on the resonance structure and low-energy baseline of the rate coefficient.

  18. Measurement of the helium 23S metastable atom density by observation of the change in the 23S-23P emission line shape due to radiation reabsorption

    NASA Astrophysics Data System (ADS)

    Shikama, T.; Ogane, S.; Iida, Y.; Hasuo, M.

    2016-01-01

    In helium discharge plasmas, the relative emission intensities of the fine-structure transitions belonging to the HeI 23S-23P transition can be affected by radiation reabsorption. Since the magnitude of the reabsorption depends on the density and temperature of the 23S metastable atoms, their density can be determined by measuring the 23S-23P emission line shape using a high wavelength-resolution spectrometer. In this study, the applicable conditions of the method in terms of the opacity and line broadening are revealed, and possible causes of errors in the measurement, i.e. spatial distributions of the density and temperature and the effects of external magnetic and electric fields, are investigated. The effect of reabsorption under an external magnetic field is experimentally confirmed using a glow discharge plasma installed in a superconducting magnet.

  19. The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Peru.

    PubMed

    Gamero, Emma Castro; Morales Pedraza, Jorge

    2009-05-01

    The tissue bank "Rosa Guerzoni Chambergo" (RGCTB) located at the Child's Health Institute was inaugurated in 1996, with the financial and technical support of the IAEA program on radiation and tissue banking. Since 1998, the biological bandage of fresh and lyophilised pigskin, amnion and bone tissue is processed routinely in this bank. In all cases, the tissue is sterilised with the use of Cobalt-60 radiation, process carried out at the Laboratories of Irradiation of the Peruvian Institute of Nuclear Energy (IPEN). The tissue bank in the Child's Health Institute helped to save lives in an accident occurred in Lima, when a New Year's fireworks celebration ran out of control in January 2002. Nearly 300 people died in the tragic blaze and hundreds more were seriously burned and injured. Eight Lima hospitals and clinics suddenly were faced with saving the lives of severely burned men, women and children. Fortunately, authorities were ready to respond to the emergency. More than 1,600 dressings were sterilised and supplied to Lima surgeons. The efforts helped save the lives of patients who otherwise might not have survived the Lima fire. Between 1998 and September 2007, 35,012 tissue grafts were produced and irradiated. Radiation sterilised tissues are used by 20 national medical institutions as well as 17 private health institutions. The tissue bank established in Peru with the support of the IAEA is now producing the following tissues: pigskin dressings, fresh and freeze-dried; bone allografts, chips, wedges and powdered, and amnion dressings air-dried. It is also now leading the elaboration of national standards, assignment being entrusted by ONDT (Organización Nacional de Donación y Transplantes; National Organisation on Donation and Transplant). This among other will permit the accreditation of the tissue bank. In this task is also participating IPEN. PMID:18612849

  20. Solid cancer mortality associated with chronic external radiation exposure at the French atomic energy commission and nuclear fuel company.

    PubMed

    Metz-Flamant, C; Samson, E; Caër-Lorho, S; Acker, A; Laurier, D

    2011-07-01

    Studies of nuclear workers make it possible to directly quantify the risks associated with ionizing radiation exposure at low doses and low dose rates. Studies of the CEA (Commissariat à l'Energie Atomique) and AREVA Nuclear Cycle (AREVA NC) cohort, currently the most informative such group in France, describe the long-term risk to nuclear workers associated with external exposure. Our aim is to assess the risk of mortality from solid cancers among CEA and AREVA NC nuclear workers and its association with external radiation exposure. Standardized mortality ratios (SMRs) were calculated and internal Poisson regressions were conducted, controlling for the main confounding factors [sex, attained age, calendar period, company and socioeconomic status (SES)]. During the period 1968-2004, there were 2,035 solid cancers among the 36,769 CEA-AREVA NC workers. Cumulative external radiation exposure was assessed for the period 1950-2004, and the mean cumulative dose was 12.1 mSv. Mortality rates for all causes and all solid cancers were both significantly lower in this cohort than in the general population. A significant excess of deaths from pleural cancer, not associated with cumulative external dose, was observed, probably due to past asbestos exposure. We observed a significant excess of melanoma, also unassociated with dose. Although cumulative external dose was not associated with mortality from all solid cancers, the central estimated excess relative risk (ERR) per Sv of 0.46 for solid cancer mortality was higher than the 0.26 calculated for male Hiroshima and Nagasaki A-bomb survivors 50 years or older and exposed at the age of 30 years or older. The modification of our results after stratification for SES demonstrates the importance of this characteristic in occupational studies, because it makes it possible to take class-based lifestyle differences into account, at least partly. These results show the great potential of a further joint international study of

  1. Truth or consequence--Bo Lindell's contribution to radiation protection.

    PubMed

    Valentin, J

    1995-01-01

    Bo Lindell, former chairman and emeritus member of ICRP, former chairman of UNSCEAR, former Director General and emeritus worker of the Swedish RAdiation Protection Institute, is a phenomenon. His profound influence on radiation protection, and indeed on environmental protection and risk research in general, includes a profuse flow of scientific publications on all aspects of protection of man against harmful effects of radiation. In this context, perhaps his most important efforts hitherto are those relating to nuclear power. The concept of dose commitment, invented by Bo Lindell, is used worldwide to regulate emissions of radioactive substances, taking into account not only the often trivial dose to immediate bystanders, but the global effect over long time-frames. In the long run, his continuing personal influence on radiation protection as a branch of science and a kind of role model for other types of environmental protection may attain an even greater importance.

  2. Electron beam radiation damages of α-alumina (0,1¯,1) surfaces with different atomic terminations

    NASA Astrophysics Data System (ADS)

    Wang, Z. L.; Howie, A.

    1990-02-01

    Damaging processes of an electron beam to α-alumina (0,1¯,1) surfaces are investigated using the combined techniques of reflection electron microscopy (REM), scanning reflection electron microscopy (SREM), reflection electron energy-loss spectroscopy (REELS) and secondary electron imaging (SEI). It is shown that the surface domains terminated with oxygen layers are rapidly damaged and appear with dark contrast in REM images. These domains later turn back to bright contrast after the top oxygen layer is removed. The surface domains terminated with aluminium layers are almost undamaged and appear with bright contrast in REM images. The relationship between the surface layer structure and its damaging rate is described. Reflection energy loss valence spectra are not much influenced by the nature of the atomic termination or the damage process. Termination effects can however be observed in the secondary electron signal although the explanation for this is not clear.

  3. Analysis of the polarization-dependent rate of associative ionization of radiatively excited Na(3p) atoms

    NASA Astrophysics Data System (ADS)

    Jones, Dumont M.; Dahler, John S.

    1985-01-01

    Kircz, Morgenstern, and Nienhuis [Phys. Rev. Lett. 48, 610 (1982)] have measured the cross section for the associative ionization of partially oriented pairs of excited [(3p) 2P3/2] sodium atoms. Here, we extract information from these data about the identities of the participating adiabatic Born-Oppenheimer states of Na2. It is definitely established that more than one of these states is involved. The greatest contributor is the X 1Σ+g state with the dominant molecular-orbital configuration σ2g (at small internuclear separations). It is highly probable that only one other state (either the 1Σ+g or 3Σ-g state with the dominant molecular-orbital configuration π2u) is involved, but a small contribution from one state (1Πu or 3Πu) with the configuration σgπu cannot be unequivocally dismissed.

  4. Evidence of radiation-induced reduction of height and body weight from repeated measurements of adults exposed in childhood to the atomic bombs

    SciTech Connect

    Otake, Masanori; Funamoto, Sachiyo; Fujikoshi, Yasunori; Schull, W.J.

    1994-10-01

    Reduction of growth from exposure to atomic bomb radiation has been examined using individuals under 10 years old at the time of the bombing (ATB) and a growth curve analysis based on measurements of height and weight made in the course of the 4th-7th cycles of the Adult Health Study examinations (1964-1972). As expected, the largest difference in growth to emerge is between males and females. However, a highly significant reduction of growth associated with dose (DS86) was observed among those survivors for whom four repeated measurements of height and weight were available. Longitudinal analysis of a more extended data set (n = 821), using expected values based on simple linear regression models fitted to the three available sets of measurements of height and weight on the 254 individuals with a missing measurement, also indicates a significant radiation-related growth reduction. The possible contribution of such factors as poor nutrition and disruption of normal family life in the years immediately after the war is difficult to evaluate, but the effects of socioeconomic factors on the analysis of these data are discussed. 33 refs., 5 figs., 3 tabs.

  5. Evidence of radiation-induced reduction of height and body weight from repeated measurements of adults exposed in childhood to the atomic bombs.

    PubMed

    Otake, M; Fujikoshi, Y; Funamoto, S; Schull, W J

    1994-10-01

    Reduction of growth from exposure to atomic bomb radiation has been examined using individuals under 10 years old at the time of the bombing (ATB) and a growth curve analysis based on measurements of height and weight made in the course of the 4th-7th cycles of the Adult Health Study examinations (1964-1972). As expected, the largest difference in growth to emerge is between males and females. However, a highly significant reduction of growth associated with dose (DS86) was observed among those survivors for whom four repeated measurements of height and weight were available. Longitudinal analysis of a more extended data set (n = 821), using expected values based on simple linear regression models fitted to the three available sets of measurements of height and weight on the 254 individuals with a missing measurement, also indicates a significant radiation-related growth reduction. The possible contribution of such factors as poor nutrition and disruption of normal family life in the years immediately after the war is difficult to evaluate, but the effects of socioeconomic factors on the analysis of these data are discussed.

  6. Measurement of the blackbody radiation shift of the {sup 133}Cs hyperfine transition in an atomic fountain

    SciTech Connect

    Levi, Filippo; Calonico, Davide; Lorini, Luca; Micalizio, Salvatore; Godone, Aldo

    2004-09-01

    We used a Cs fountain to measure the Stark shift of the ground-state hyperfine transition frequency in cesium (9.2 GHz) due to the electric field of the blackbody radiation. The relative shift at 300 K deduced from our measurements, including the leading and the second-order term in temperature, is (-1.45{+-}0.09)x10{sup -14} and agrees with our recent theoretical evaluation (-1.51{+-}0.07)x10{sup -14} [Micalizio et al. Phys. Rev. A 69, 053401 (2004)]. These values differ from that currently used (-1.735{+-}0.003)x10{sup -14}, with significant implications on frequency standards accuracy, on clocks comparison and on a variety of high-precision physics tests, such as the time stability of fundamental constants.

  7. TR-LIF LIFETIME MEASUREMENTS AND HFR+CPOL CALCULATIONS OF RADIATIVE PARAMETERS IN VANADIUM ATOM (V I)

    SciTech Connect

    Wang, Q.; Jiang, L. Y.; Shang, X.; Tian, Y. S.; Dai, Z. W.; Quinet, P.; Palmeri, P.; Zhang, W. E-mail: Pascal.quinet@umons.ac.be

    2014-04-01

    Radiative lifetimes of 79 levels belonging to the 3d {sup 3}4s4p, 3d {sup 4}4p, 3d {sup 3}4s5p, 3d {sup 4}5p, and 3d {sup 3}4s4d configurations of V I with energy from 26,604.807 to 46,862.786 cm{sup –1} have been measured using time-resolved laser-induced fluorescence (TR-LIF) spectroscopy in laser-produced plasma. The lifetime values reported in this paper are in the range of 3.3-494 ns, and the uncertainties of these measurements are within ±10%. A good agreement was obtained with previous data. HFR+CPOL calculations have been performed and used to combine the calculated branching fractions with the available experimental lifetimes to determine semi-empirical transition probabilities for 784 V I transitions.

  8. Radioisotopic energy conversion system (RECS): A new radioisotopic power cell, based on nuclear, atomic, and radiation transport principles

    NASA Astrophysics Data System (ADS)

    Steinfelds, Eric Victor

    The topic of this thesis is the development of the Radioisotope Energy Conversion System (RECS) in a project which is utilizing analytical computational assisted design and some experimental Research in the investigation of fluorescers and effective transducers with the appropriate energy range choice for the conversion of energy. It is desirable to increase the efficiency in electrical power from the raw kinetic power available from the radioactive material within radioisotope power generators. A major step in this direction is the development and use of Radioisotope Energy Conversion Systems to supplement and ideally replace Radioactive Thermal Generators (RTG). It is possible to achieve electrical conversion efficiencies exceeding 25% for RECS power devices compared to only 9 percent efficiency for RTG's. The theoretical basis with existent materials for the potential achievability of efficiencies above 25% is documented within this thesis. The fundamental RECS consists of a radioisotope radiative source (C1), a mediating fluorescent gas (C2) which readily absorbs energy from the beta particles (or alpha's) and subsequently emits blue or UV photons, photovoltaic cells (C3) to convert the blue and UV photons into electrical energy [2], and electrical circuitry (C4). Solid State inspired component (C3), due to its theoretical (and attainable) high efficiency, is a large step ahead of the RTG design concept. The radioisotope flux source produces the beta(-) particles or alpha particles. Geometrically, presently, we prefer to have the ambient fluorescent gas surround the radioisotope flux source. Our fluorescer shall be a gas such as Krypton. Our specifically wide band-gap photovoltaic cells shall have gap energies which are slightly less than that of UV photons produced by the fluorescing gas. Diamond and Aluminum Nitride sample materials are good potential choices for photovoltaic cells, as is explained here in. Out of the material examples discussed, the highest

  9. Natural radiation sources, including some lessons for nuclear waste management

    NASA Astrophysics Data System (ADS)

    Métivier, Henri

    2002-09-01

    The average effective dose at the global level is, according to UNSCEAR, estimated to be 2.4 mSv from naturally occurring sources. This average value can be divided as follows: 1.3 mSv associated with radon, 0.39 mSv from cosmic radiation, 0.46 mSv from terrestrial radiation, and 0.23 mSv from internal radiation, radon excluded. These values can vary quite significantly depending on the place of habitation. Despite this large variation, no sound epidemiological study has yet shown the health effects on the most exposed populations, apart from a few studies concerning radon, but in which the predominant role of tobacco is difficult to determine. To cite this article: H. Métivier, C. R. Physique 3 (2002) 1035-1048.

  10. Giant light enhancement in atomic clusters

    SciTech Connect

    Gadomsky, O. N. Gadomskaya, I. V.; Altunin, K. K.

    2009-07-15

    We show that the polarizing effect of the atoms in an atomic cluster can lead to full compensation of the radiative damping of excited atomic states, a change in the sign of the dispersion of the atomic polarizability, and giant light enhancement by the atomic cluster.

  11. Atomic bomb health benefits.

    PubMed

    Luckey, T D

    2008-01-01

    Media reports of deaths and devastation produced by atomic bombs convinced people around the world that all ionizing radiation is harmful. This concentrated attention on fear of miniscule doses of radiation. Soon the linear no threshold (LNT) paradigm was converted into laws. Scientifically valid information about the health benefits from low dose irradiation was ignored. Here are studies which show increased health in Japanese survivors of atomic bombs. Parameters include decreased mutation, leukemia and solid tissue cancer mortality rates, and increased average lifespan. Each study exhibits a threshold that repudiates the LNT dogma. The average threshold for acute exposures to atomic bombs is about 100 cSv. Conclusions from these studies of atomic bomb survivors are: One burst of low dose irradiation elicits a lifetime of improved health.Improved health from low dose irradiation negates the LNT paradigm.Effective triage should include radiation hormesis for survivor treatment.

  12. Effects of atomic bomb radiation on differentiation of B lymphocytes and on the function of concanavalin A-induced suppressor T lymphocytes

    SciTech Connect

    Yamada, Y.; Neriishi, S.; Ishimaru, T.; Shimba, N.; Hamilton, H.B.; Ohgushi, Y.; Koyanagi, M.; Ichimaru, M.

    1985-02-01

    The differentiation of peripheral blood B lymphocytes into immunoglobulin-producing cells (Ig-PC) by pokeweed mitogen (PWM) and the function of concanavalin A (Con A)-induced suppressor T lymphocytes were examined to elucidate the late effects of atomic bomb radiation. A total of 140 individuals, 70 with an exposure dose of 100 rad or more and an equal number with an exposure dose of 0 rad matched by sex and age, were selected from the Nagasaki Adult Health Study (AHS) sample. Both the differentiation of peripheral blood B lymphocytes into Ig-PC by PWM and the function of Con A-induced suppressor T lymphocytes tended to be more depressed in the exposed group than in the control group, but a statistically significant difference could not be observed between the two groups. The function of Con A-induced suppressor T lymphocytes tended to decrease with age, but a statistical significance was detected only for percentage suppression against IgM-PC.

  13. Peaceful atoms in agriculture and food: how the politics of the Cold War shaped agricultural research using isotopes and radiation in post war divided Germany.

    PubMed

    Zachmann, Karin

    2015-01-01

    During the Cold War, the super powers advanced nuclear literacy and access to nuclear resources and technology to a first-class power factor. Both national governments and international organizations developed nuclear programs in a variety of areas and promoted the development of nuclear applications in new environments. Research into the use of isotopes and radiation in agriculture, food production, and storage gained major importance as governments tried to promote the possibility of a peaceful use of atomic energy. This study is situated in divided Germany as the intersection of the competing socio-political systems and focuses on the period of the late 1940s and 1950s. It is argued that political interests and international power relations decisively shaped the development of "nuclear agriculture". The aim is to explore whether and how politicians in both parts of the divided country fostered the new field and exerted authority over the scientists. Finally, it examines the ways in which researchers adapted to the altered political conditions and expectations within the two political structures, by now fundamentally different. PMID:26775431

  14. Peaceful atoms in agriculture and food: how the politics of the Cold War shaped agricultural research using isotopes and radiation in post war divided Germany.

    PubMed

    Zachmann, Karin

    2015-01-01

    During the Cold War, the super powers advanced nuclear literacy and access to nuclear resources and technology to a first-class power factor. Both national governments and international organizations developed nuclear programs in a variety of areas and promoted the development of nuclear applications in new environments. Research into the use of isotopes and radiation in agriculture, food production, and storage gained major importance as governments tried to promote the possibility of a peaceful use of atomic energy. This study is situated in divided Germany as the intersection of the competing socio-political systems and focuses on the period of the late 1940s and 1950s. It is argued that political interests and international power relations decisively shaped the development of "nuclear agriculture". The aim is to explore whether and how politicians in both parts of the divided country fostered the new field and exerted authority over the scientists. Finally, it examines the ways in which researchers adapted to the altered political conditions and expectations within the two political structures, by now fundamentally different.

  15. Accelerating NLTE radiative transfer by means of the Forth-and-Back Implicit Lambda Iteration: A two-level atom line formation in 2D Cartesian coordinates

    NASA Astrophysics Data System (ADS)

    Milić, Ivan; Atanacković, Olga

    2014-10-01

    State-of-the-art methods in multidimensional NLTE radiative transfer are based on the use of local approximate lambda operator within either Jacobi or Gauss-Seidel iterative schemes. Here we propose another approach to the solution of 2D NLTE RT problems, Forth-and-Back Implicit Lambda Iteration (FBILI), developed earlier for 1D geometry. In order to present the method and examine its convergence properties we use the well-known instance of the two-level atom line formation with complete frequency redistribution. In the formal solution of the RT equation we employ short characteristics with two-point algorithm. Using an implicit representation of the source function in the computation of the specific intensities, we compute and store the coefficients of the linear relations J=a+bS between the mean intensity J and the corresponding source function S. The use of iteration factors in the ‘local’ coefficients of these implicit relations in two ‘inward’ sweeps of 2D grid, along with the update of the source function in other two ‘outward’ sweeps leads to four times faster solution than the Jacobi’s one. Moreover, the update made in all four consecutive sweeps of the grid leads to an acceleration by a factor of 6-7 compared to the Jacobi iterative scheme.

  16. Technical Evaluation of the NASA Model for Cancer Risk to Astronauts Due to Space Radiation

    NASA Technical Reports Server (NTRS)

    2012-01-01

    At the request of NASA, the National Research Council's (NRC's) Committee for Evaluation of Space Radiation Cancer Risk Model reviewed a number of changes that NASA proposes to make to its model for estimating the risk of radiation-induced cancer in astronauts. The NASA model in current use was last updated in 2005, and the proposed model would incorporate recent research directed at improving the quantification and understanding of the health risks posed by the space radiation environment. NASA's proposed model is defined by the 2011 NASA report Space Radiation Cancer Risk Projections and Uncertainties 2010 (Cucinotta et al., 2011). The committee's evaluation is based primarily on this source, which is referred to hereafter as the 2011 NASA report, with mention of specific sections or tables cited more formally as Cucinotta et al. (2011). The overall process for estimating cancer risks due to low linear energy transfer (LET) radiation exposure has been fully described in reports by a number of organizations. They include, more recently: (1) The "BEIR VII Phase 2" report from the NRC's Committee on Biological Effects of Ionizing Radiation (BEIR) (NRC, 2006); (2) Studies of Radiation and Cancer from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2006), (3) The 2007 Recommendations of the International Commission on Radiological Protection (ICRP), ICRP Publication 103 (ICRP, 2007); and (4) The Environmental Protection Agency s (EPA s) report EPA Radiogenic Cancer Risk Models and Projections for the U.S. Population (EPA, 2011). The approaches described in the reports from all of these expert groups are quite similar. NASA's proposed space radiation cancer risk assessment model calculates, as its main output, age- and gender-specific risk of exposure-induced death (REID) for use in the estimation of mission and astronaut-specific cancer risk. The model also calculates the associated uncertainties in REID. The general approach for

  17. Lung cancer mortality between 1950 and 1987 after exposure to fractionated moderate-dose-rate ionizing radiation in the Canadian fluoroscopy cohort study and a comparison with lung cancer mortality in the atomic bomb survivors study

    SciTech Connect

    Howe, G.R.

    1995-06-01

    Current lung cancer risk estimates after exposure to low-linear energy transfer radiation such as X rays are based on studies of people exposed to such radiation at high dose rates, for example the atomic bomb survivors. Radiobiology and animal experiments suggest that risks from exposure at low to moderate dose rates, for example medical diagnostic procedures, may be overestimated by such risk models, but data for humans to examine this issue are limited. In this paper we report on lung cancer mortality between 1950 and 1987 in a cohort of 64,172 Canadian tuberculosis patients, of whom 39% were exposed to highly fractionated multiple chest fluoroscopies leading to a mean lung radiation dose of 1.02 Sv received at moderate dose rates. These data have been used to estimate the excess relative risk per sievert of lung cancer mortality, and this is compared directly to estimates derived from 75,991 atomic bomb survivors. Based on 1,178 lung cancer deaths in the fluoroscopy study, there was no evidence of any positive association between risk and dose, with the relative risk at 1 Sv being 1.00 (95% confidence interval 0.94, 1.07), which contrasts with that based on the atomic bomb survivors, 1.60 (1.27, 1.99). The difference in effect between the two studies almost certainly did not arise by chance (P = 0.0001). This study provides strong support from data for humans for a substantial fractionation/dose-rate effect for low-linear energy transfer radiation and lung cancer risk. This implies that lung cancer risk from exposures to such radiation at present-day dose rates is likely to be lower than would be predicted by current radiation risk models based on studies of high-dose-rate exposures. 25 refs., 8 tabs.

  18. Synchrotron radiation photoemission study of interfacial electronic structure of HfO{sub 2} on In{sub 0.53}Ga{sub 0.47}As(001)-4 × 2 from atomic layer deposition

    SciTech Connect

    Pi, T. W. E-mail: gkwer@verizon.net E-mail: mhong@phys.ntu.edu.tw; Lin, T. D.; Chang, Y. C.; Hong, M. E-mail: gkwer@verizon.net E-mail: mhong@phys.ntu.edu.tw; Lin, H. Y.; Kwo, J. E-mail: gkwer@verizon.net E-mail: mhong@phys.ntu.edu.tw; Wertheim, G. K. E-mail: gkwer@verizon.net E-mail: mhong@phys.ntu.edu.tw

    2014-01-27

    The growth of a passivating layer on a In{sub 0.53}Ga{sub 0.47}As(001)-4 × 2 surface by atomic-layer deposition of tetrakis[ethylmethylamino]Hafnium (TEMAHf)) followed by the water pulse was investigated by synchrotron radiation photoemission. The Hf atoms maintain four-fold coordination, both after the initial TEMAHf deposition and the subsequent water pulse. The Hf atoms initially bond to the As dangling bonds of the surface As atom located on the edges of the raised ridges. One EMA ligand is removed in this process. Subsequent water exposure substitutes OH ligand for one or more remaining EMA ligands. These in turn react with TEMAHf to form Hf-O-Hf bonds allowing the hafnium oxides to grow. The surface In atoms on the terrace of the raised ridges were partially removed, but none bonded of the precursor atoms. Correlations between the interfacial electronic structure and the electric performance are discussed.

  19. Reviews Book: Big Ben Book: Mini Weapons of Mass Destruction Equipment: Waves and Radiation Sample Pack Book: The Exploratorium Science Snackbook Book: Super Structures Book: The Universe and the Atom

    NASA Astrophysics Data System (ADS)

    2010-11-01

    WE RECOMMEND Mini Weapons of Mass Destruction A pictorial guide to making safe mini weapons Waves and Radiation Sample Pack Pack shines light on the electromagnetic spectrum The Exploratorium Science Snackbook Book is full of ideas for fascinating physics demonstrations Super Structures The science of bridges, buildings, dams and engineering WORTH A LOOK Big Ben The physics of the world-famous clock The Universe and the Atom A comprehensive guide to physics

  20. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Investigation of the populations of excited states of barium atoms in a laser plasma

    NASA Astrophysics Data System (ADS)

    Burimov, V. N.; Zherikhin, A. N.; Popkov, V. L.

    1995-02-01

    Laser-induced fluorescence was used in an investigation of the populations of the ground and excited (6s5d 3D1 and 3D2) states of Ba atoms in a plasma formed by laser ablation of Y—Ba—Cu—O target. A nonequilibrium velocity distribution of the atoms was detected. At large distances from the target about 4% of the atoms were in an excited state.

  1. Cancer in atomic bomb survivors

    SciTech Connect

    Shigematsu, I.; Kagan, A.

    1986-01-01

    This book presents information on the following topics: sampling of atomic bomb survivors and method of cancer detection in Hiroshima and Nagasaki; atomic bomb dosimetry for epidemiological studies of survivors in Hiroshima and Nagasaki; tumor and tissue registries in Hiroshima and Nagasaki; the cancer registry in Nagasaki, with atomic bomb survivor data, 1973-1977; cancer mortality; methods for study of delayed health effects of a-bomb radiation; experimental radiation carcinogenesis in rodents; leukemia, multiple myeloma, and malignant lymphoma; cancer of the thyroid and salivary glands; malignant tumors in atomic bomb survivors with special reference to the pathology of stomach and lung cancer; colorectal cancer among atomic bomb survivors; breast cancer in atomic bomb survivors; and ovarian neoplasms in atomic bomb survirors.

  2. Symposium on atomic spectroscopy (SAS-83): abstracts and program

    SciTech Connect

    Not Available

    1983-09-01

    Abstracts of papers given at the symposium are presented. Session topics include: Rydbergs, optical radiators, and planetary atoms; highly ionized atoms; ultraviolet radiation; theory, ion traps, and laser cooling; beam foil; and astronomy. (GHT)

  3. Visualization of atom's orbits.

    PubMed

    Kim, Byungwhan

    2014-02-01

    High-resolution imaging techniques have been used to obtain views of internal shapes of single atoms or columns of atoms. This review article focuses on the visualization of internal atomic structures such as the configurations of electron orbits confined to atoms. This is accomplished by applying visualization techniques to the reported images of atoms or molecules as well as static and dynamic ions in a plasma. It was found that the photon and electron energies provide macroscopic and microscopic views of the orbit structures of atoms, respectively. The laser-imaged atoms showed a rugged orbit structure, containing alternating dark and bright orbits believed to be the pathways for an externally supplied laser energy and internally excited electron energy, respectively. By contrast, the atoms taken by the electron microscopy provided a structure of fine electron orbits, systematically formed in increasing order of grayscale representing the energy state of an orbit. This structure was identical to those of the plasma ions. The visualized electronic structures played a critical role in clarifying vague postulates made in the Bohr model. Main features proposed in the atomic model are the dynamic orbits absorbing an externally supplied electromagnetic energy, electron emission from them while accompanying light radiation, and frequency of electron waves not light. The light-accompanying electrons and ionic speckles induced by laser light signify that light is composed of electrons and ions.

  4. Atom-to-atom interactions for atomic layer deposition of trimethylaluminum on Ga-rich GaAs(001)-4 × 6 and As-rich GaAs(001)-2 × 4 surfaces: a synchrotron radiation photoemission study

    PubMed Central

    2013-01-01

    High-resolution synchrotron radiation photoemission was employed to study the effects of atomic-layer-deposited trimethylaluminum (TMA) and water on Ga-rich GaAs(001)-4 × 6 and As-rich GaAs(001)-2 × 4 surfaces. No high charge states were found in either As 3d or Ga 3d core-level spectra before and after the deposition of the precursors. TMA adsorption does not disrupt the GaAs surface structure. For the (4 × 6) surface, the TMA precursor existed in both chemisorbed and physisorbed forms. In the former, TMA has lost a methyl group and is bonded to the As of the As-Ga dimer. Upon water purge, the dimethylaluminum-As group was etched off, allowing the now exposed Ga to bond with oxygen. Water also changed the physisorbed TMA into the As-O-Al(CH3)2 configuration. This configuration was also found in 1 cycle of TMA and water exposure of the (2 × 4) surface, but with a greater strength, accounting for the high interface defect density in the mid-gap region. PMID:23587341

  5. Isodose mapping of terrestrial gamma radiation dose rate of Selangor state, Kuala Lumpur and Putrajaya, Malaysia.

    PubMed

    Sanusi, M S M; Ramli, A T; Gabdo, H T; Garba, N N; Heryanshah, A; Wagiran, H; Said, M N

    2014-09-01

    A terrestrial gamma radiation survey for the state of Selangor, Kuala Lumpur and Putrajaya was conducted to obtain baseline data for environmental radiological health practices. Based on soil type, geological background and information from airborne survey maps, 95 survey points statistically representing the study area were determined. The measured doses varied according to geological background and soil types. They ranged from 17 nGy h(-1) to 500 nGy h(-1). The mean terrestrial gamma dose rate in air above the ground was 182 ± 81 nGy h(-1). This is two times higher than the average dose rate of terrestrial gamma radiation in Malaysia which is 92 nGy h(-1) (UNSCEAR 2000). An isodose map was produced to represent exposure rate from natural sources of terrestrial gamma radiation.

  6. Analysis of radiation exposure, 2nd Marine Corps Provisional Atomic Exercise Brigade, Exercise Desert Rock V, Operation Upshot-Knothole. Technical report

    SciTech Connect

    Frank, G.; Weitz, R.; Goetz, J.; Klemm, J.; Schweizer, T.

    1983-02-05

    The radiation dose to Marine Brigade participants in Exercise Desert Rock V (Operation Upshot-Knothole, 1953) is reconstructed for each major brigade element. The exercise was centered around Shot Badger, from which almost all of the radiation dose resulted. Calculations and limited film badge dosimetry indicate typical doses of 3 to 4 rem for brigade personnel; however, some personnel of one battalion exceeded the 6 rem dose limit during an aborted maneuver.

  7. International Atomic Energy Agency study with referring physicians on patient radiation exposure and its tracking: a prospective survey using a web-based questionnaire

    PubMed Central

    Rehani, Madan M; Berris, Theocharis

    2012-01-01

    Objectives To assess the following themes among referring physicians: (A) importance of acquiring information about previous diagnostic exposures; (B) knowledge about radiation doses involved, familiarity with radiation units and, age-related radiosensitivity; (C) opinion on whether patients should be provided information about radiation dose and (D) self-assessment of appropriateness of referrals. Design A prospective survey using a web-based questionnaire. Setting International survey among referring physicians. Participants Referring physicians from 28 countries. Main outcome measures Knowledge, opinion and practice of the four themes of the survey. Results All 728 responses from 28 countries (52.3% from developed and 47.7% from developing countries) indicated that while the vast majority (71.7%) of physicians feel that being aware of history of CT scans would always or mostly lead them to a better decision on referring patients for CT scans, only 43.4% often enquire about it. The majority of referring physicians (60.5%) stated that having a system that provides quick information about patient exposure history would be useful. The knowledge about radiation doses involved is poor, as only one-third (34.7%) of respondents chose the correct option of the number of chest x-rays with equivalence of a CT scan. In total, 70.9% of physicians stated that they do not feel uncomfortable when patients ask about radiation risk from CT scans they prescribe. Most physicians (85.6%) assessed that they have rarely prescribed CT scans of no clinical use in patient management. Conclusions This first ever multinational survey among referring physicians from 28 countries indicates support for a system that provides radiation exposure history of the patient, demonstrates poor knowledge about radiation doses, supports radiation risk communication with patients and mandatory provisions for justification of a CT examination. PMID:22997065

  8. Radiation-associated lung cancer: a comparison of the histology of lung cancers in uranium miners and survivors of the atomic bombings of Hiroshima and Nagasaki.

    PubMed

    Land, C E; Shimosato, Y; Saccomanno, G; Tokuoka, S; Auerbach, O; Tateishi, R; Greenberg, S D; Nambu, S; Carter, D; Akiba, S

    1993-05-01

    A binational panel of Japanese and American pulmonary pathologists reviewed tissue slides of lung cancer cases diagnosed among Japanese A-bomb survivors and American uranium miners and classified the cases according to histological subtype. Blind reviews were completed on slides from 92 uranium miners and 108 A-bomb survivors, without knowledge of population, sex, age, smoking history, or level of radiation exposure. Consensus diagnoses were obtained with respect to principal subtype, including squamous-cell cancer, small-cell cancer, adenocarcinoma, and less frequent subtypes. The results were analyzed in terms of population, radiation dose, and smoking history. As expected, the proportion of squamous-cell cancer was positively related to smoking history in both populations. The relative frequencies of small-cell cancer and adenocarcinoma were very different in the two populations, but this difference was accounted for adequately by differences in radiation dose or, more specifically, dose-based relative risk estimates based on published data. Radiation-induced cancers appeared more likely to be of the small-cell subtype, and less likely to be adenocarcinomas, in both populations. The data appeared to require no additional explanation in terms of radiation quality (alpha particles vs gamma rays), uniform or local irradiation, inhaled vs external radiation source, or other population difference. PMID:8387679

  9. Atomic polarizabilities

    SciTech Connect

    Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  10. Radiation environment at high-mountains stations and onboard spacecraft

    SciTech Connect

    Spurny, Frantisek; Ploc, Ondrej; Jadrmickova, Iva

    2008-08-07

    Radiation environment has been studied at high-mountain observatories and onboard spacecraft. The most important contribution to this environment at high-mountain observatories represents cosmic radiation component. We have been studied this environment in two high-mountain observatories: one situated on the top of Lomnicky Stit, High Tatras, Slovakia, and another one close to the top of Moussala, Rila, Bulgaria (Basic Environment Observatory--BEO). The studies have been performed using: an energy deposition spectrometer with a Si-diode (MDU) developed at BAS, Sofia, permitting to estimate non-neutron as well as neutron component of the radiation field; other active equipment designated to measure natural radiation background, and thermoluminescent detectors as passive dosimeters. Basic dosimetry characteristics of these fields are presented, analyzed, and discussed; they are also compared with the estimation of cosmic radiation component as published in the Report of UNSCEAR 2000. Measuring instruments mentioned above, together with an LET spectrometer based on chemically etched track detectors have been also used to characterize radiation environment onboard spacecraft, particularly International Space Station. They have been exposed on the surface and/or inside a phantom. Some of results obtained are presented, and discussed.

  11. Public exposure due to external gamma background radiation in boundary areas of Iran.

    PubMed

    Pooya, S M Hosseini; Dashtipour, M R; Enferadi, A; Orouji, T

    2015-09-01

    A monitoring program in boundary areas of a country is an appropriate way to indicate the level of public exposure. In this research, gamma background radiation was measured using TL dosimeters at 12 boundary areas as well as in the capital city of Iran during the period 2010 to 2011. The measurements were carried out in semi-annual time intervals from January to June and July to December in each year. The maximum average dose equivalent value measured was approximately 70 μSv/month for Tehran city. Also, the average dose values obtained were less than 40 μSv/month for all the cities located at the sea level except that of high level natural radiation area of Ramsar, and more than 55 μSv/month for the higher elevation cities. The public exposure due to ambient gamma dose equivalent in Iran is within the levels reported by UNSCEAR.

  12. Natural radiation doses to the population in a granitic region in Spain.

    PubMed

    López, R; García-Talavera, M; Pardo, R; Deban, L; Nalda, J C

    2004-01-01

    The global average effective dose from natural radiation sources is estimated to be 2.4 mSv y(-1). Nevertheless, local variations in the radiation exposure may differ by orders of magnitude. In this paper, we study a rural area in western Salamanca (Spain) where doses are potentially well above the stated average value. Its geology consists mostly of granite and schist, presenting various uranium mineralisations, some of which were exploited in former years. Water samples, both surface and groundwater, were collected in selected villages and measured by liquid-scintillation spectrometry. 222Rn in dwellings was determined in dwellings by means of short-term measurements, using Picorad vials and long-term measurements with CR-39 detectors. The committed effective doses to the inhabitants due to indoor 222Rn and 222Rn and 226Ra in drinking water were assessed using the dose conversion factors proposed in the UNSCEAR 2000 report.

  13. Enhanced nonlinear coupling in the keV x-ray range: Xe(L) hollow atom excitation with Xe(M) radiation at ℏω ≅ 1 keV

    NASA Astrophysics Data System (ADS)

    Borisov, Alex B.; McCorkindale, John C.; Poopalasingam, Sankar; Longworth, James W.; Rhodes, Charles K.

    2015-08-01

    Anomalously enhanced nonlinear electromagnetic coupling can arise from ordered driven collective motions in many electron systems. The augmented strength of the interaction can be expressed as an effective increase in the fine structure constant α in which α → Z2α, where Z specifies the number of electrons involved in the ordered response to the external field. The present work illustrates this phenomenon in the x-ray range with the observation of the 5-photon nonlinear excitation of Xe(L)* hollow atom states that are generated by intense (˜7 × 1015 W cm-2) Xe(M) radiation {γ }{{M}} at ˜1 keV. The nonlinear cross section experimentally determined for the 5{γ }{{M}} + Xe → [Xeq+(L)]* + qe- amplitude is {σ }5 ˜ 2 × 10-21 cm2. The matching theoretical cross section corresponds to Z = 18, an outcome indicating the participation of the full Xe(4d105s25p6) supershell, a dynamic feature of Xe that also plays a significant role in the linear photoionization of neutral Xe atoms in the kilovolt region. For the high-intensity 5γ nonlinear coupling, the outcome for the Xe(L)* hollow atom excitation is an enhancement of the strength of the interaction by a factor of ˜1012 and, with Z2α > 1, a fundamentally new region of strong coupling is entered. The experimental value of {σ }5 is likewise shown to be in very good accord with an earlier analysis that estimated the upper bound of cross sections for high-order multi-photon cross sections in the combined high-Z and high-intensity limit. These results forecast the general presence of comparably enhanced coupling strengths in the interaction of sufficiently intense (I ≥ 7 × 1015 W cm-2) x-rays with high-Z atoms and molecules.

  14. Radiation Hydrodynamics

    SciTech Connect

    Castor, J I

    2003-10-16

    The discipline of radiation hydrodynamics is the branch of hydrodynamics in which the moving fluid absorbs and emits electromagnetic radiation, and in so doing modifies its dynamical behavior. That is, the net gain or loss of energy by parcels of the fluid material through absorption or emission of radiation are sufficient to change the pressure of the material, and therefore change its motion; alternatively, the net momentum exchange between radiation and matter may alter the motion of the matter directly. Ignoring the radiation contributions to energy and momentum will give a wrong prediction of the hydrodynamic motion when the correct description is radiation hydrodynamics. Of course, there are circumstances when a large quantity of radiation is present, yet can be ignored without causing the model to be in error. This happens when radiation from an exterior source streams through the problem, but the latter is so transparent that the energy and momentum coupling is negligible. Everything we say about radiation hydrodynamics applies equally well to neutrinos and photons (apart from the Einstein relations, specific to bosons), but in almost every area of astrophysics neutrino hydrodynamics is ignored, simply because the systems are exceedingly transparent to neutrinos, even though the energy flux in neutrinos may be substantial. Another place where we can do ''radiation hydrodynamics'' without using any sophisticated theory is deep within stars or other bodies, where the material is so opaque to the radiation that the mean free path of photons is entirely negligible compared with the size of the system, the distance over which any fluid quantity varies, and so on. In this case we can suppose that the radiation is in equilibrium with the matter locally, and its energy, pressure and momentum can be lumped in with those of the rest of the fluid. That is, it is no more necessary to distinguish photons from atoms, nuclei and electrons, than it is to distinguish

  15. The interaction of 193-nm excimer laser radiation with single-crystal zinc oxide: The generation of atomic Zn line emission at laser fluences below breakdown

    SciTech Connect

    Khan, Enamul H.; Langford, S. C.; Dickinson, J. T.; Boatner, L. A.

    2013-08-28

    The production of gas phase atomic and ionic line spectra accompanying the high laser fluence irradiation of solid surfaces is well known and is most often due to the production and interaction of high densities of atoms, ions, and electrons generated from laser-induced breakdown. The resulting plasma expands and moves rapidly away from the irradiated spot and is accompanied by intense emission of light. This type of “plume” is well studied and is frequently exploited in the technique of chemical analysis known as laser induced breakdown spectroscopy. Here, we describe a similar but weaker emission of light generated in vacuum by the laser irradiation of single crystal ZnO at fluences well below breakdown; this emission consists entirely of optical line emission from excited atomic Zn. We compare the properties of the resulting laser-generated gas-phase light emission (above and below breakdown) and describe a mechanism for the production of the low-fluence optical emission resulting from a fortuitous choice of material and laser wavelength.

  16. Competition Effect in Atomic-Molecular System

    NASA Technical Reports Server (NTRS)

    Jia, Suotang; Qin, Lijuan; Qian, Zuliang; Wang, Zugeng; Wang, Gang; Zhou, Guosheng

    1996-01-01

    The competition effects among the processes of atomic ionization, optical pumped stimulated radiation (OPSR), four-wave frequency mixing (FWFM) and molecular stimulated diffuse band radiation at the atomic two-photon resonance of 3S approaches 4D in Na2 - Na mixture were observed. The dip at the two-photon resonance in the excitation spectrum for the diffuse-band radiation was interpreted as suppression of population in 4D state.

  17. Atomic supersymmetry

    NASA Technical Reports Server (NTRS)

    Kostelecky, V. Alan

    1993-01-01

    Atomic supersymmetry is a quantum-mechanical supersymmetry connecting the properties of different atoms and ions. A short description of some established results in the subject are provided and a few recent developments are discussed including the extension to parabolic coordinates and the calculation of Stark maps using supersymmetry-based models.

  18. Atomic Calligraphy

    NASA Astrophysics Data System (ADS)

    Imboden, Matthias; Pardo, Flavio; Bolle, Cristian; Han, Han; Tareen, Ammar; Chang, Jackson; Christopher, Jason; Corman, Benjamin; Bishop, David

    2013-03-01

    Here we present a MEMS based method to fabricate devices with a small number of atoms. In standard semiconductor fabrication, a large amount of material is deposited, after which etching removes what is not wanted. This technique breaks down for structures that approach the single atom limit, as it is inconceivable to etch away all but one atom. What is needed is a bottom up method with single or near single atom precision. We demonstrate a MEMS device that enables nanometer position controlled deposition of gold atoms. A digitally driven plate is swept as a flux of gold atoms passes through an aperture. Appling voltages on four comb capacitors connected to the central plate by tethers enable nanometer lateral precision in the xy plane over 15x15 sq. microns. Typical MEMS structures have manufacturing resolutions on the order of a micron. Using a FIB it is possible to mill apertures as small as 10 nm in diameter. Assuming a low incident atomic flux, as well as an integrated MEMS based shutter with microsecond response time, it becomes possible to deposit single atoms. Due to their small size and low power consumption, such nano-printers can be mounted directly in a cryogenic system at ultrahigh vacuum to deposit clean quench condensed metallic structures.

  19. ATOMIC AND MOLECULAR PHYSICS: Generation of Continuum Extreme-Ultraviolet Radiation by Carrier-Envelope-Phase-Stabilized 5-fs Laser Pulses

    NASA Astrophysics Data System (ADS)

    Teng, Hao; Yun, Chen-Xia; Zhu, Jiang-Feng; Han, Hai-Nian; Zhong, Xin; Zhang, Wei; Hou, Xun; Wei, Zhi-Yi

    2009-11-01

    Coherent extreme-ultraviolet (XUV) radiation is studied by interaction of carrier-envelope (CE) phase stabilized high energy 5-fs infrared (800 nm) laser pulses with neon gas at a repetition rate of 1 kHz. A broadband continuum XUV spectrum in the cut-off region is demonstrated when the CE phase is shifted to about zero, rather than modulated spectral harmonics when setting of CE phase is nonzero. The results show the generation of isolated attosecond XUV pulses.

  20. Laboratory astrophysics and atomic physics using the NASA/GSFC microcalorimeter spectrometers at the LLNL Electron Beam Ion Trap and Radiation Properties Facility

    SciTech Connect

    Brown, G; Beiersdorfer, P; Boyce, K; Chen, H; Gu, M F; Kahn, S; Kelley, R; Kilbourne, C; May, M; Porter, F S; Szymkowiak, A; Thorn, D; Widmann, K

    2005-08-18

    The 32 pixel laboratory microcalorimeter spectrometer built by the NASA/Goddard Space Flight Center is now an integral part of the spectroscopy suite used routinely by the electron beam ion trap and radiative properties group at the Lawrence Livermore National Laboratory. The second generation laboratory instrument, dubbed the XRS/EBIT, is nearly identical to the XRS instrument on the Suzaku X-ray Observatory, formerly Astro-E2. The detector array is from the same processed wafer and uses the same HgTe absorbers. it is being used to measure the photon emission from a variety of radiation sources. These include x-ray emission from laboratory simulated celestial sources, x-ray emission from highly charged ions of Au, and x-ray emission following charge exchange and radiative electron capture. The wide range of applications demonstrates the versatility of a high-resolution, high-efficiency low temperature detector that is able to collect data continually with minimal operator servicing.

  1. RADIATION SOURCES

    DOEpatents

    Brucer, M.H.

    1958-04-15

    A novel long-lived source of gamma radiation especially suitable for calibration purposes is described. The source of gamma radiation is denoted mock iodine131, which comprises a naixture of barium-133 and cesium-137. The barium and cesium are present in a barium-cesium ratio of approximately 5.7/1 to 14/1, uniformly dispersed in an ion exchange resin and a filter surrounding the resin comprised of a material of atomic number below approximately 51, and substantially 0.7 to 0.9 millimeter thick.

  2. Effective atomic number, energy loss and radiation damage studies in some materials commonly used in nuclear applications for heavy charged particles such as H, C, Mg, Fe, Te, Pb and U

    NASA Astrophysics Data System (ADS)

    Kurudirek, Murat

    2016-05-01

    Commonly used nuclear physics materials such as water, concrete, Pb-glass, paraffin, freon and P 10 gases, some alloys such as brass, bronze, stainless-steel and some scintillators such as anthracene, stilbene and toluene have been investigated with respect to the heavy charged particle interaction as means of projected range and effective atomic number (Zeff) in the energy region 10 keV to 10 MeV. Calculations were performed for heavy ions such as H, C, Mg, Fe, Te, Pb and U. Also, the energy loss and radiation damage were studied using SRIM Monte Carlo code for anthracene for different heavy ions of 100 keV kinetic energy. It has been observed that the variation in Zeff becomes less when the atomic number of the ions increase. Glass-Pb, bronze, brass, stainless-steel and Freon gas were found to vary less than 10% in the energy region 10 keV to 10 MeV. For total proton interaction, discrepancies up to 10% and 18% between two databases namely PSTAR and SRIM were noted in mass stopping power and Zeff of water, respectively. The range calculations resulted with a conclusion that the metal alloys and glass-Pb have lowest values of ranges confirming best shielding against energetic heavy ions whereas freon and P 10 gases have the highest values of ranges in the entire energy region. The simulation results showed that the energy loss (%) to target electrons decreases as the Z of the incident ion increases. Also, it was observed that the radiation damage first increases with Z of the ion and then keeps almost constant for ions with Z≥52.

  3. Modeling of neutrals in the Linac4 H{sup −} ion source plasma: Hydrogen atom production density profile and H{sub α} intensity by collisional radiative model

    SciTech Connect

    Yamamoto, T. Shibata, T.; Ohta, M.; Yasumoto, M.; Nishida, K.; Hatayama, A.; Mattei, S.; Lettry, J.; Sawada, K.; Fantz, U.

    2014-02-15

    To control the H{sup 0} atom production profile in the H{sup −} ion sources is one of the important issues for the efficient and uniform surface H{sup −} production. The purpose of this study is to construct a collisional radiative (CR) model to calculate the effective production rate of H{sup 0} atoms from H{sub 2} molecules in the model geometry of the radio-frequency (RF) H{sup −} ion source for Linac4 accelerator. In order to validate the CR model by comparison with the experimental results from the optical emission spectroscopy, it is also necessary for the model to calculate Balmer photon emission rate in the source. As a basic test of the model, the time evolutions of H{sup 0} production and the Balmer H{sub α} photon emission rate are calculated for given electron energy distribution functions in the Linac4 RF H{sup −} ion source. Reasonable test results are obtained and basis for the detailed comparisons with experimental results have been established.

  4. Structure and oscillational motion of /sup 57/Fe atoms in interstitial sites in Al as determined from interference of Moessbauer. gamma. radiation

    SciTech Connect

    Pauling, L.

    1981-12-01

    The first excited site of the /sup 57/Fe atom entrapped in an interstitial site in aluminum, as reported by W. Petry, G. Vogl, and W. Mansel (Phys. Rev. Lett. 45, 1862 (1980)) from a Moessbauer spectroscopic study of a single crystal, is analyzed by consideration of the value of the Hooke's law constant of the Fe-Al bonds obtained from the values for elemental Fe and Al. The eight wavefunctions for the eightfold nearly degenerate excited state are described as 2s1p1d1f hybrids of three-dimensional harmonic oscillator wavefunctions relative to the center of the undistorted Al/sub 6/ octahedron or as localized 1s functions relative to the center of the distorted octahedron. These considerations provide a qualitative understanding of the observations on this system.

  5. Radiation dose response estimation with emphasis on low dose range using restricted cubic splines: application to all solid cancer mortality data, 1950-2003, in atomic bomb survivors.

    PubMed

    Nakashima, Eiji

    2015-07-01

    Using the all solid cancer mortality data set of the Life Span Study (LSS) cohort from 1950 to 2003 (LSS Report 14) data among atomic bomb survivors, excess relative risk (ERR) statistical analyses were performed using the second degree polynomial and the threshold and restricted cubic spline (RCS) dose response models. For the RCS models with 3 to 7 knots of equally spaced percentiles with margins in the dose range greater than 50 mGy, the dose response was assumed to be linear at less than 70 to 90 mGy. Due to the skewed dose distribution of atomic bomb survivors, the current knot system for the RCS analysis results in a detailed depiction of the dose response as less than approximately 0.5 Gy. The 6 knot RCS models for the all-solid cancer mortality dose response of the whole dose or less than 2 Gy were selected with the AIC model selection criterion and fit significantly better (p < 0.05) than the linear (L) model. The usual RCS includes the L-global model but not the quadratic (Q) nor linear-quadratic (LQ) global models. The authors extended the RCS to include L or LQ global models by putting L or LQ constraints on the cubic spline in the lower and upper tails, and the best RCS model selected with AIC criterion was the usual RCS with L-constraints in both the lower and upper tails. The selected RCS had a linear dose-response model in the lower dose range (i.e., < 0.2-0.3 Gy) and was compatible with the linear no-threshold (LNT) model in this dose range. The proposed method is also useful in describing the dose response of a specific cancer or non-cancer disease incidence/mortality.

  6. Kinetic Atom.

    ERIC Educational Resources Information Center

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  7. Acting Atoms.

    ERIC Educational Resources Information Center

    Farin, Susan Archie

    1997-01-01

    Describes a fun game in which students act as electrons, protons, and neutrons. This activity is designed to help students develop a concrete understanding of the abstract concept of atomic structure. (DKM)

  8. First Analysis of Radiative Properties of Moderate-atomic-number Planar Wire Arrays on Zebra at UNR at Higher Current of 1.7 MA*

    NASA Astrophysics Data System (ADS)

    Safronova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Astanovitskiy, A.; Legalloudec, B.; Presura, R.; Shrestha, I.; Williamson, K. M.; Shlyaptseva, V.; Weller, M. E.; Ouart, N. D.; Keim, S. F.; Osborne, G. C.; Chuvatin, A. S.; Coverdale, C. A.

    2010-11-01

    The analysis of implosions of Cu and Ag planar wire array (PWA) loads recently performed at the enhanced 1.7 MA Zebra generator at UNR is presented. Experiments were performed with a Load Current Multiplier with a 1cm anode-cathode gap (twice shorter than in a standard 1 MA mode). A full diagnostic set included more than ten different beam-lines with the major focus on time-gated and time-integrated x-ray imaging and spectra, total radiation yields, and fast, filtered x-ray detector data. In particular, the experimental results for a double PWA load consisting of twelve 10μm Cu wires in each row (total mass M ˜ 175 μg) and a much heavier single PWA load consisting of ten 30μm Ag wires (M ˜ 750 μg) were analyzed using a set of theoretical codes. The effects of both a decreased a-c gap and an increased current on radiative properties of these loads are discussed. * This work was supported by NNSA/DOE Coop. Agr. DE-FC52-06NA27588, 27586, and 27616. Sandia is a multi-program laboratory operated by Sandia Co., a LMC, for the US DOE under Contract DE-AC04-94AL85000.

  9. Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H₂O₂ for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry.

    PubMed

    Bezerra, Marcos A; Souza, Antônio D S; Oliveira, Rafael V; Oliveira, Djalma M; Cardoso, Luiz A M; Sousa Filho, Hélio R

    2015-03-01

    This work proposes the use of photo-oxidation degradation with UV radiation/H2O2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS). Three variables (pH, irradiation time and buffer concentration) were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H2O2 30%, v/v) were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL-1, and the precision levels expressed as relative standard (%RSD, 0.5 µg mL-1) were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level. PMID:25806976

  10. Transition of radiative recombination channels from delocalized states to localized states in a GaInP alloy with partial atomic ordering: a direct optical signature of Mott transition?

    NASA Astrophysics Data System (ADS)

    Su, Z. C.; Ning, J. Q.; Deng, Z.; Wang, X. H.; Xu, S. J.; Wang, R. X.; Lu, S. L.; Dong, J. R.; Yang, H.

    2016-03-01

    Anderson localization is a predominant phenomenon in condensed matter and materials physics. In fact, localized and delocalized states often co-exist in one material. They are separated by a boundary called the mobility edge. Mott transition may take place between these two regimes. However, it is widely recognized that an apparent demonstration of Anderson localization or Mott transition is a challenging task. In this article, we present a direct optical observation of a transition of radiative recombination dominant channels from delocalized (i.e., local extended) states to Anderson localized states in the GaInP base layer of a GaInP/GaAs single junction solar cell by the means of the variable-temperature electroluminescence (EL) technique. It is found that by increasing temperature, we can boost a remarkable transition of radiative recombination dominant channels from the delocalized states to the localized states. The delocalized states are induced by the local atomic ordering domains (InP/GaP monolayer superlattices) while the localized states are caused by random distribution of indium (gallium) content. The efficient transfer and thermal redistribution of carriers between the two kinds of electronic states was revealed to result in both a distinct EL mechanism transition and an electrical resistance evolution with temperature. Our study gives rise to a self-consistent precise picture for carrier localization and transfer in a GaInP alloy, which is an extremely technologically important energy material for fabricating high-efficiency photovoltaic devices.

  11. Transition of radiative recombination channels from delocalized states to localized states in a GaInP alloy with partial atomic ordering: a direct optical signature of Mott transition?

    PubMed

    Su, Z C; Ning, J Q; Deng, Z; Wang, X H; Xu, S J; Wang, R X; Lu, S L; Dong, J R; Yang, H

    2016-04-01

    Anderson localization is a predominant phenomenon in condensed matter and materials physics. In fact, localized and delocalized states often co-exist in one material. They are separated by a boundary called the mobility edge. Mott transition may take place between these two regimes. However, it is widely recognized that an apparent demonstration of Anderson localization or Mott transition is a challenging task. In this article, we present a direct optical observation of a transition of radiative recombination dominant channels from delocalized (i.e., local extended) states to Anderson localized states in the GaInP base layer of a GaInP/GaAs single junction solar cell by the means of the variable-temperature electroluminescence (EL) technique. It is found that by increasing temperature, we can boost a remarkable transition of radiative recombination dominant channels from the delocalized states to the localized states. The delocalized states are induced by the local atomic ordering domains (InP/GaP monolayer superlattices) while the localized states are caused by random distribution of indium (gallium) content. The efficient transfer and thermal redistribution of carriers between the two kinds of electronic states was revealed to result in both a distinct EL mechanism transition and an electrical resistance evolution with temperature. Our study gives rise to a self-consistent precise picture for carrier localization and transfer in a GaInP alloy, which is an extremely technologically important energy material for fabricating high-efficiency photovoltaic devices. PMID:26960547

  12. Cold Light from Hot Atoms and Molecules

    SciTech Connect

    Lister, Graeme; Curry, John J.

    2011-05-11

    The introduction of rare earth atoms and molecules into lighting discharges led to great advances in efficacy of these lamps. Atoms such as Dy, Ho and Ce provide excellent radiation sources for lighting applications, with rich visible spectra, such that a suitable combination of these elements can provide high quality white light. Rare earth molecules have also proved important in enhancing the radiation spectrum from phosphors in fluorescent lamps. This paper reviews some of the current aspects of lighting research, particularly rare earth chemistry and radiation, and the associated fundamental atomic and molecular data.

  13. Interaction of wide band gap single crystals with 248 nm excimer laser radiation. XII. The emission of negative atomic ions from alkali halides

    SciTech Connect

    Kimura, Kenichi; Langford, S. C.; Dickinson, J. T.

    2007-12-01

    Many wide band gap materials yield charged and neutral emissions when exposed to sub-band-gap laser radiation at power densities below the threshold for optical breakdown and plume formation. In this work, we report the observation of negative alkali ions from several alkali halides under comparable conditions. We observe no evidence for negative halogen ions, in spite of the high electron affinities of the halogens. Significantly, the positive and negative alkali ions show a high degree of spatial and temporal overlap. A detailed study of all the relevant particle emissions from potassium chloride (KCl) suggests that K{sup -} is formed by the sequential attachment of two electrons to K{sup +}.

  14. High atomic weight, high-energy radiation (HZE) induces transcriptional responses shared with conventional stresses in addition to a core "DSB" response specific to clastogenic treatments.

    PubMed

    Missirian, Victor; Conklin, Phillip A; Culligan, Kevin M; Huefner, Neil D; Britt, Anne B

    2014-01-01

    Plants exhibit a robust transcriptional response to gamma radiation which includes the induction of transcripts required for homologous recombination and the suppression of transcripts that promote cell cycle progression. Various DNA damaging agents induce different spectra of DNA damage as well as "collateral" damage to other cellular components and therefore are not expected to provoke identical responses by the cell. Here we study the effects of two different types of ionizing radiation (IR) treatment, HZE (1 GeV Fe(26+) high mass, high charge, and high energy relativistic particles) and gamma photons, on the transcriptome of Arabidopsis thaliana seedlings. Both types of IR induce small clusters of radicals that can result in the formation of double strand breaks (DSBs), but HZE also produces linear arrays of extremely clustered damage. We performed these experiments across a range of time points (1.5-24 h after irradiation) in both wild-type plants and in mutants defective in the DSB-sensing protein kinase ATM. The two types of IR exhibit a shared double strand break-repair-related damage response, although they differ slightly in the timing, degree, and ATM-dependence of the response. The ATM-dependent, DNA metabolism-related transcripts of the "DSB response" were also induced by other DNA damaging agents, but were not induced by conventional stresses. Both Gamma and HZE irradiation induced, at 24 h post-irradiation, ATM-dependent transcripts associated with a variety of conventional stresses; these were overrepresented for pathogen response, rather than DNA metabolism. In contrast, only HZE-irradiated plants, at 1.5 h after irradiation, exhibited an additional and very extensive transcriptional response, shared with plants experiencing "extended night." This response was not apparent in gamma-irradiated plants.

  15. GRASP: General-purpose Relativistic Atomic Structure Package

    NASA Astrophysics Data System (ADS)

    Grant, I. P.; McKenzie, B. J.; Norrington, P. H.; Mayers, D. F.; Pyper, N. C.

    2016-09-01

    GRASP (General-purpose Relativistic Atomic Structure Package) calculates atomic structure, including energy levels, radiative rates (A-values) and lifetimes; it is a fully relativistic code based on the jj coupling scheme.

  16. Atomic research

    NASA Technical Reports Server (NTRS)

    Hadaway, James B.; Connatser, Robert; Cothren, Bobby; Johnson, R. B.

    1993-01-01

    Work performed by the University of Alabama in Huntsville's (UAH) Center for Applied Optics (CAO) entitled Atomic Research is documented. Atomic oxygen (AO) effects on materials have long been a critical concern in designing spacecraft to withstand exposure to the Low Earth Orbit (LEO) environment. The objective of this research effort was to provide technical expertise in the design of instrumentation and experimental techniques for analyzing materials exposed to atomic oxygen in accelerated testing at NASA/MSFC. Such testing was required to answer fundamental questions concerning Space Station Freedom (SSF) candidate materials and materials exposed to atomic oxygen aboard the Long-Duration Exposure Facility (LDEF). The primary UAH task was to provide technical design, review, and analysis to MSFC in the development of a state-of-the-art 5eV atomic oxygen beam facility required to simulate the RAM-induced low earth orbit (LEO) AO environment. This development was to be accomplished primarily at NASA/MSFC. In support of this task, contamination effects and ultraviolet (UV) simulation testing was also to be carried out using NASA/MSFC facilities. Any materials analysis of LDEF samples was to be accomplished at UAH.

  17. Actuated atomizer

    NASA Technical Reports Server (NTRS)

    Tilton, Charles (Inventor); Weiler, Jeff (Inventor); Palmer, Randall (Inventor); Appel, Philip (Inventor)

    2008-01-01

    An actuated atomizer is adapted for spray cooling or other applications wherein a well-developed, homogeneous and generally conical spray mist is required. The actuated atomizer includes an outer shell formed by an inner ring; an outer ring; an actuator insert and a cap. A nozzle framework is positioned within the actuator insert. A base of the nozzle framework defines swirl inlets, a swirl chamber and a swirl chamber. A nozzle insert defines a center inlet and feed ports. A spool is positioned within the coil housing, and carries the coil windings having a number of turns calculated to result in a magnetic field of sufficient strength to overcome the bias of the spring. A plunger moves in response to the magnetic field of the windings. A stop prevents the pintle from being withdrawn excessively. A pintle, positioned by the plunger, moves between first and second positions. In the first position, the head of the pintle blocks the discharge passage of the nozzle framework, thereby preventing the atomizer from discharging fluid. In the second position, the pintle is withdrawn from the swirl chamber, allowing the atomizer to release atomized fluid. A spring biases the pintle to block the discharge passage. The strength of the spring is overcome, however, by the magnetic field created by the windings positioned on the spool, which withdraws the plunger into the spool and further compresses the spring.

  18. A comparative study of thorium activity in NORM and high background radiation area.

    PubMed

    Sahoo, S K; Ishikawa, T; Tokonami, S; Sorimachi, A; Kranrod, C; Janik, M; Hosoda, M; Hassan, N M; Chanyotha, S; Parami, V K; Yonehara, H; Ramola, R C

    2010-10-01

    Several industrial processes are known to enrich naturally occurring radioactive materials (NORM). To assess such processes with respect to their radiological relevance, characteristic parameters describing this enrichment will lead to interesting information useful to UNSCEAR. In case of mineral treatment plants, the high temperatures used in smelting and refining processes lead to high concentrations of (238)U and (232)Th. Also due to thermal power combustion, concentration of U and Th in the fly ash increases manifold. NORM samples were collected from a Thailand mineral treatment plant and Philippine coal-fired thermal power plants for investigation. Some studies are initiated from a high background radiation area near Gopalpur of Orissa state in India. These NORM samples were analysed by gamma-ray spectrometry as well as inductively coupled plasma mass spectrometry. The radioactivity in case of Orissa soil samples is found to be mainly contributed from thorium. This study attempts to evaluate levels of thorium activity in NORM samples.

  19. Atom Interferometry

    SciTech Connect

    Kasevich, Mark

    2008-05-08

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton's constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gyroscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be used to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  20. Atom Interferometry

    SciTech Connect

    Mark Kasevich

    2008-05-07

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton’s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  1. Atom Interferometry

    ScienceCinema

    Mark Kasevich

    2016-07-12

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton’s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  2. The evolution and impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Asia and the Pacific region.

    PubMed

    Morales Pedraza, Jorge; Phillips, Glyn O

    2009-05-01

    The Asia and the Pacific region was within the IAEA program on radiation and tissue banking, the most active region. Most of the tissue banks in the Asia and the Pacific region were developed during the late 1980s and 1990s. The initial number of tissue banks established or supported by the IAEA program in the framework of the RCA Agreement for Asia and the Pacific region was 18. At the end of 2006, the number of tissue banks participating, in one way or another in the IAEA program was 59. Since the beginning of the implementation of the IAEA program in Asia and the Pacific region 63,537 amnion and 44,282 bone allografts were produced and 57,683 amnion and 36,388 bone allografts were used. The main impact of the IAEA program in the region was the following: the establishment or consolidation of at least 59 tissue banks in 15 countries in the region (the IAEA supported directly 16 of these banks); the improvement on the quality and safety of tissues procured and produced in the region reaching international standards; the implementation of eight national projects, two regional projects and two interregional projects; the elaboration of International Standards, a Code of Practice and a Public Awareness Strategies and, the application of quality control and quality assurances programs in all participating tissue banks.

  3. Atomic Oxygen Task

    NASA Technical Reports Server (NTRS)

    Hadaway, James B.

    1997-01-01

    This report details work performed by the Center for Applied Optics (CAO) at the University of Alabama in Huntsville (UAH) on the contract entitled 'Atomic Oxygen Task' for NASA's Marshall Space Flight Center (contract NAS8-38609, Delivery Order 109, modification number 1). Atomic oxygen effects on exposed materials remain a critical concern in designing spacecraft to withstand exposure in the Low Earth Orbit (LEO) environment. The basic objective of atomic oxygen research in NASA's Materials & Processes (M&P) Laboratory is to provide the solutions to material problems facing present and future space missions. The objective of this work was to provide the necessary research for the design of specialized experimental test configurations and development of techniques for evaluating in-situ space environmental effects, including the effects of atomic oxygen and electromagnetic radiation on candidate materials. Specific tasks were performed to address materials issues concerning accelerated environmental testing as well as specifically addressing materials issues of particular concern for LDEF analysis and Space Station materials selection.

  4. Imaging enzyme kinetics at atomic resolution.

    PubMed

    Spence, John; Lattman, Eaton

    2016-07-01

    Serial crystallography at a synchrotron has been used to obtain time-resolved atomic resolution density maps of enzyme catalysis in copper nitrite reductase. Similar XFEL studies, intended to out-run radiation damage, will also soon appear. PMID:27437108

  5. Radiation protection in space

    SciTech Connect

    Blakely, E.A.; Fry, R.J.M.

    1995-02-01

    The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in the present state of knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared to previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space.

  6. Radiation cataract.

    PubMed

    Kleiman, N J

    2012-01-01

    Until very recently, ocular exposure guidelines were based on the assumption that radiation cataract is a deterministic event requiring threshold doses generally greater than 2 Gy. This view was, in part, based on older studies which generally had short follow-up periods, failed to take into account increasing latency as dose decreased, had relatively few subjects with doses below a few Gy, and were not designed to detect early lens changes. Newer findings, including those in populations exposed to much lower radiation doses and in subjects as diverse as astronauts, medical workers, atomic bomb survivors, accidentally exposed individuals, and those undergoing diagnostic or radiotherapeutic procedures, strongly suggest dose-related lens opacification at significantly lower doses. These observations resulted in a recent re-evaluation of current lens occupational exposure guidelines, and a proposed lowering of the presumptive radiation cataract threshold to 0.5 Gy/year and the occupational lens exposure limit to 20 mSv/year, regardless of whether received as an acute, protracted, or chronic exposure. Experimental animal studies support these conclusions and suggest a role for genotoxicity in the development of radiation cataract. Recent findings of a low or even zero threshold for radiation-induced lens opacification are likely to influence current research efforts and directions concerning the cellular and molecular mechanisms underlying this pathology. Furthermore, new guidelines are likely to have significant implications for occupational and/or accidental exposure, and the need for occupational eye protection (e.g. in fields such as interventional medicine).

  7. Material Effectiveness for Radiation Shielding

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Materials with a smaller mean atomic mass, such as lithium (Li) hydride and polyethylene, make the best radiation shields for astronauts. The materials have a higher density of nuclei and are better able to block incoming radiation. Also, they tend to produce fewer and less dangerous secondary particles after impact with incoming radiation.

  8. Gravitational Wave Detection with Single-Laser Atom Interferometers

    NASA Technical Reports Server (NTRS)

    Yu, Nan; Tinto, Massimo

    2011-01-01

    A new design for a broadband detector of gravitational radiation relies on two atom interferometers separated by a distance L. In this scheme, only one arm and one laser are used for operating the two atom interferometers. The innovation here involves the fact that the atoms in the atom interferometers are not only considered as perfect test masses, but also as highly stable clocks. Atomic coherence is intrinsically stable, and can be many orders of magnitude more stable than a laser.

  9. A novel RET rearrangement (ACBD5/RET) by pericentric inversion, inv(10)(p12.1;q11.2), in papillary thyroid cancer from an atomic bomb survivor exposed to high-dose radiation.

    PubMed

    Hamatani, Kiyohiro; Eguchi, Hidetaka; Koyama, Kazuaki; Mukai, Mayumi; Nakachi, Kei; Kusunoki, Yoichiro

    2014-11-01

    During analysis of RET/PTC rearrangements in papillary thyroid cancer (PTC) among atomic bomb survivors, a cDNA fragment of a novel type of RET rearrangement was identified in a PTC patient exposed to a high radiation dose using the improved 5' RACE method. This gene resulted from the fusion of the 3' portion of RET containing tyrosine kinase domain to the 5' portion of the acyl-coenzyme A binding domain containing 5 (ACBD5) gene, by pericentric inversion inv(10)(p12.1;q11.2); expression of the fusion gene was confirmed by RT-PCR. ACBD5 gene is ubiquitously expressed in various human normal tissues including thyroid. Full-length cDNA of the ACBD5-RET gene was constructed and then examined for tumorigenicity. Enhanced phosphorylation of ERK proteins in the MAPK pathway was observed in NIH3T3 cells transfected with expression vector encoding the full-length ACBD5/RET cDNA, while this was not observed in the cells transfected with empty expression vector. Stable NIH3T3 transfectants with ACBD5-RET cDNA induced tumor formation after their injection into nude mice. These findings suggest that the ACBD5-RET rearrangement is causatively involved in the development of PTC.

  10. A novel RET rearrangement (ACBD5/RET) by pericentric inversion, inv(10)(p12.1;q11.2), in papillary thyroid cancer from an atomic bomb survivor exposed to high-dose radiation.

    PubMed

    Hamatani, Kiyohiro; Eguchi, Hidetaka; Koyama, Kazuaki; Mukai, Mayumi; Nakachi, Kei; Kusunoki, Yoichiro

    2014-11-01

    During analysis of RET/PTC rearrangements in papillary thyroid cancer (PTC) among atomic bomb survivors, a cDNA fragment of a novel type of RET rearrangement was identified in a PTC patient exposed to a high radiation dose using the improved 5' RACE method. This gene resulted from the fusion of the 3' portion of RET containing tyrosine kinase domain to the 5' portion of the acyl-coenzyme A binding domain containing 5 (ACBD5) gene, by pericentric inversion inv(10)(p12.1;q11.2); expression of the fusion gene was confirmed by RT-PCR. ACBD5 gene is ubiquitously expressed in various human normal tissues including thyroid. Full-length cDNA of the ACBD5-RET gene was constructed and then examined for tumorigenicity. Enhanced phosphorylation of ERK proteins in the MAPK pathway was observed in NIH3T3 cells transfected with expression vector encoding the full-length ACBD5/RET cDNA, while this was not observed in the cells transfected with empty expression vector. Stable NIH3T3 transfectants with ACBD5-RET cDNA induced tumor formation after their injection into nude mice. These findings suggest that the ACBD5-RET rearrangement is causatively involved in the development of PTC. PMID:25175022

  11. Atomic rivals

    SciTech Connect

    Goldschmidt, B.

    1990-01-01

    This book is a memoir of rivalries among the Allies over the bomb, by a participant and observer. Nuclear proliferation began in the uneasy wartime collaboration of the United States, England, Canada, and Free France to produce the atom bomb. Through the changes of history, a young French chemist had a role in almost every act of this international drama. This memoir is based on Goldschmidt's own recollections, interviews with other leading figures, and 3,000 pages of newly declassified documents in Allied archives. From his own start as Marie Curie's lab assistant, Goldschmidt's career was closely intertwined with Frances complicated rise to membership in the nuclear club. As a refugee from the Nazis, he became part of the wartime nuclear energy project in Canada and found himself the only French scientist to work (although briefly) on the American atom bomb project.

  12. Atomic arias

    NASA Astrophysics Data System (ADS)

    Crease, Robert P.

    2009-01-01

    The American composer John Adams uses opera to dramatize controversial current events. His 1987 work Nixon in China was about the landmark meeting in 1972 between US President Richard Nixon and Chairman Mao Zedong of China; The Death of Klinghoffer (1991) was a musical re-enactment of an incident in 1985 when Palestinian terrorists kidnapped and murdered a wheelchair-bound Jewish tourist on a cruise ship. Adams's latest opera, Doctor Atomic, is also tied to a controversial event: the first atomic-bomb test in Alamogordo, New Mexico, on 16 June 1945. The opera premièred in San Francisco in 2005, had a highly publicized debut at the Metropolitan Opera in New York in 2008, and will have another debut on 25 February - with essentially the same cast - at the English National Opera in London.

  13. Atomic physics

    SciTech Connect

    Livingston, A.E.; Kukla, K.; Cheng, S.

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  14. Radiation carcinogenesis in man: influence of dose-response models and risk projection models in the estimation of risk coefficients following exposure to low-level radiation

    SciTech Connect

    Fabrikant, J.I.

    1982-02-01

    The somatic effects of concern in human populations exposed to low doses and low dose rates of ionizing radiations are those that may be induced by mutation in individual cells, singly or in small numbers. The most important of these is considered to be cancer induction. Current knowledge of the carcinogenic effect of radiation in man has been reviewed in two recent reports: the 1977 UNSCEAR Report; and the 1980 BEIR-III Report. Both reports emphasize that cancers of the breast, thyroid, hematopoietic tissues, lung, and bone can be induced by radiation. Other cancers, including the stomach, pancreas, pharynx, lymphatic, and perhaps all tissues of the body, may also be induced by radiation. Both reports calculate risk estimates in absolute and relative terms for low-dose, low-LET whole-body exposure, and for leukemia, breast cancer, thyroid cancer, lung cancer, and other cancers. These estimates derive from exposure and cancer incidence data at high doses and at high dose rates. There are no compelling scientific reasons to apply these values of risk to the very low doses and low dose rates of concern in human radiation protection. In the absence of reliable human data for calculating risk estimates, dose-response models have been constructed from extrapolations of animal data and high-dose-rate human data for projection of estimated risks at low doses and low dose rates. (ERB)

  15. Radiation health research, 1986 - 1990

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A collection of 225 abstracts of radiation research sponsored by NASA during the period 1986 through 1990 is reported. Each abstract was categorized within one of four discipline areas: physics, biology, risk assessment, and microgravity. Topic areas within each discipline were assigned as follows: Physics - atomic physics, nuclear science, space radiation, radiation transport and shielding, and instrumentation; Biology - molecular biology, cellular radiation biology, tissue, organs and organisms, radioprotectants, and plants; Risk assessment - radiation health and epidemiology, space flight radiation health physics, inter- and intraspecies extrapolation, and radiation limits and standards; and Microgravity. When applicable subareas were assigned for selected topic areas. Keywords and author indices are provided.

  16. Thermal nonequilibrium in partially ionized atomic oxygen

    NASA Technical Reports Server (NTRS)

    Soon, W. H.; Kunc, J. A.

    1990-01-01

    A stationary, nonlinear collisional-radiative model for high-temperature atomic oxygen is presented. Populations of electrons, ions, and excited atoms and intensities of spectral, continuum, and dielectronic recombination lines are calculated in a wide range of conditions. Transport of radiation is included by coupling the rate equations for production of the electrons, ions, and excited atoms with the concept of the escape factors that are not constant but dependent upon plasma conditions. The calculated total continuum emission is in good agreement with existing measurements.

  17. Studies of Interstellar and Circumstellar Magnetic Field with Aligned Atoms

    NASA Astrophysics Data System (ADS)

    Lazarian, A.; Yan, H.

    2004-12-01

    Population of levels of the hyperfine and fine split ground state of an atom is affected by radiative transitions induced by anisotropic radiation flux. Such aligned atoms precess in the external magnetic field and this affects properties of polarized radiation arising from both scattering and absorption by atoms. As the result the degree of light polarization depends on the direction of the magnetic field. This provides a new tool for studies of astrophysical magnetic fields using optical and UV polarimetry. We provide calculations for several atoms and ions that can be used to study magnetic fields in interplanetary medium, interstellar medius, circumstellar regions and quasars.

  18. Rydberg States of Atoms and Molecules

    NASA Astrophysics Data System (ADS)

    Stebbings, R. F.; Dunning, F. B.

    2011-03-01

    List of contributors; Preface; 1. Rydberg atoms in astrophysics A. Dalgarno; 2. Theoretical studies of hydrogen Rydberg atoms in electric fields R. J. Damburg and V. V. Kolosov; 3. Rydberg atoms in strong fields D. Kleppner, Michael G. Littman and Myron L. Zimmerman; 4. Spectroscopy of one- and two-electron Rydberg atoms C. Fabre and S. Haroche; 5. Interaction of Rydberg atoms with blackbody radiation T. F. Gallagher; 6. Theoretical approaches to low-energy collisions of Rydberg atoms with atoms and ions A. P. Hickman, R. E. Olson and J. Pascale; 7. Experimental studies of the interaction of Rydberg atoms with atomic species at thermal energies F. Gounand and J. Berlande; 8. Theoretical studies of collisions of Rydberg atoms with molecules Michio Matsuzawa; 9. Experimental studies of thermal-energy collisions of Rydberg atoms with molecules F. B. Dunning and R. F. Stebbings; 10. High-Rydberg molecules Robert S. Freund; 11. Theory of Rydberg collisions with electrons, ions and neutrals M. R. Flannery; 12. Experimental studies of the interactions of Rydberg atoms with charged particles J. -F. Delpech; 13. Rydberg studies using fast beams Peter M. Koch; Index.

  19. Radiation transport calculations for cosmic radiation.

    PubMed

    Endo, A; Sato, T

    2012-01-01

    The radiation environment inside and near spacecraft consists of various components of primary radiation in space and secondary radiation produced by the interaction of the primary radiation with the walls and equipment of the spacecraft. Radiation fields inside astronauts are different from those outside them, because of the body's self-shielding as well as the nuclear fragmentation reactions occurring in the human body. Several computer codes have been developed to simulate the physical processes of the coupled transport of protons, high-charge and high-energy nuclei, and the secondary radiation produced in atomic and nuclear collision processes in matter. These computer codes have been used in various space radiation protection applications: shielding design for spacecraft and planetary habitats, simulation of instrument and detector responses, analysis of absorbed doses and quality factors in organs and tissues, and study of biological effects. This paper focuses on the methods and computer codes used for radiation transport calculations on cosmic radiation, and their application to the analysis of radiation fields inside spacecraft, evaluation of organ doses in the human body, and calculation of dose conversion coefficients using the reference phantoms defined in ICRP Publication 110.

  20. Radiation transport calculations for cosmic radiation.

    PubMed

    Endo, A; Sato, T

    2012-01-01

    The radiation environment inside and near spacecraft consists of various components of primary radiation in space and secondary radiation produced by the interaction of the primary radiation with the walls and equipment of the spacecraft. Radiation fields inside astronauts are different from those outside them, because of the body's self-shielding as well as the nuclear fragmentation reactions occurring in the human body. Several computer codes have been developed to simulate the physical processes of the coupled transport of protons, high-charge and high-energy nuclei, and the secondary radiation produced in atomic and nuclear collision processes in matter. These computer codes have been used in various space radiation protection applications: shielding design for spacecraft and planetary habitats, simulation of instrument and detector responses, analysis of absorbed doses and quality factors in organs and tissues, and study of biological effects. This paper focuses on the methods and computer codes used for radiation transport calculations on cosmic radiation, and their application to the analysis of radiation fields inside spacecraft, evaluation of organ doses in the human body, and calculation of dose conversion coefficients using the reference phantoms defined in ICRP Publication 110. PMID:23089013

  1. Atom Skimmers and Atom Lasers Utilizing Them

    NASA Technical Reports Server (NTRS)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  2. Screening Effects on Nonrelativistic Bremsstrahlung in the Scattering of Electrons by Neutral Atoms

    NASA Technical Reports Server (NTRS)

    Jung, Young-Dae; Lee, Kun-Sang

    1995-01-01

    Atomic screening effects on nonrelativistic electron-atom bremsstrahlung radiation are investigated using a simple analytic solution of the Thomas-Fermi model for many-electron atoms. The Born approximation is assumed for the initial and final states of the projectile electron. The results show that the screening effect is important in the soft radiation region and is decreasing with increasing radiation. These results help provide correct information about the behavior of bound electrons in the target atom in bremsstrahlung processes.

  3. Viewing minerals, atom by atom

    NASA Astrophysics Data System (ADS)

    Maggs, William Ward

    With state-of-the-art technology supported by scissors and bungy cords, Earth scientists are beginning to look at mineral surfaces and mineral-fluid interactions on an atomic scale.The instrument that can provide such a detailed view is the scanning tunneling microscope (STM), which made a great theoretical and practical splash when it was introduced in 1981 by Gerd Binnig and Heinrich Rohrer, physicists at IBM's laboratory in Zurich. They won a Nobel Prize in Physics for their work 5 years later.

  4. A photo-oxidation procedure using UV radiation/H 2O 2 for decomposition of wine samples — Determination of iron and manganese content by flame atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    dos Santos, Walter N. L.; Brandão, Geovani C.; Portugal, Lindomar A.; David, Jorge M.; Ferreira, Sérgio L. C.

    2009-06-01

    This paper proposes the use of photo-oxidation with UV radiation/H 2O 2 as sample pretreatment for the determination of iron and manganese in wines by flame atomic absorption spectrometry (FAAS). The optimization involved the study of the following variables: pH and concentration of buffer solution, concentrated hydrogen peroxide volume and irradiation time. The evaluation of sample degradation was monitored by measuring the absorbance at the maximum wavelength of red wine (530 nm). Using the experimental conditions established during the optimization (irradiation time of 30 min, oxidant volume of 2.5 mL, pH 10, and a buffer concentration of 0.15 mol L - 1 ), this procedure allows the determination of iron and manganese with limits of detection of 30 and 22 μg L - 1 , respectively, for a 5 mL volume of digested sample. The precision levels, expressed as relative standard deviation (RSD), were 2.8% and 0.65% for iron and 2.7% and 0.54% for manganese for concentrations of 0.5 and 2.0 mg L - 1 , respectively. Addition/recovery tests for evaluation of the accuracy were in the ranges of 90%-111% and 95%-107% for iron and manganese, respectively. This digestion procedure has been applied for the determination of iron and manganese in six wine samples. The concentrations varied from 1.58 to 2.77 mg L - 1 for iron and from 1.30 to 1.91 mg L - 1 for manganese. The results were compared with those obtained by an acid digestion procedure and determination of the elements by FAAS. There was no significant difference between the results obtained by the two methods based on a paired t-test (at 95% confidence level).

  5. Comment on "Atomic structure calculations and identification of EUV and SXR spectral lines in Sr XXX" by A. Goyal, I. Khatri, S. Aggarwal, A.K. Singh, M. Mohan [J Quant Spectrosc Radiat Transf 2015;161:157

    NASA Astrophysics Data System (ADS)

    Aggarwal, Kanti M.

    2015-11-01

    Recently, Goyal et al. [1] reported energies and lifetimes (τ) for the lowest 113 levels of the 2s22p5, 2s2p6, 2s22p43ℓ, 2s2p53ℓ and 2p63ℓ configurations of F-like Sr XXX. For the calculations they adopted the multi-configuration Dirac-Fock (MCDF) and the flexible atomic code (FAC). Additionally, they also listed radiative rates (A- values), oscillator strengths (f- values) and line strengths (S- values) for four types of transitions, namely electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1) and magnetic quadrupole (M2), but only from the ground to the higher excited levels. However, there are two clear anomalies in their reported data. Firstly, the f-values listed from FAC in their Tables 3-6 are larger than from MCDF by a factor of two, for all transitions. This is because they have blindly listed the output from FAC without realising that, unlike MCDF, FAC lists ωf where ω is the statistical weight, and happens to be exactly 2 in the present case. Secondly, their lifetime for level 2 (2s22p51/2 o 2P) is incorrect. This is because the dominant contributing transition for this level is 1-2 M1 for which A=3.25×106 s-1, listed (correctly) in their Table 5, and this leads to τ=3.08×10-7 s, and not 1.54×10-7 s, as listed in their Table 1.

  6. Practical Applications of Radioactivity and Nuclear Radiations

    NASA Astrophysics Data System (ADS)

    Lowenthal, Gerhart; Airey, Peter

    2005-09-01

    1. Atoms, nuclides and radionuclides; 2. Units and standards for radioactivity and radiation dosimetry and rules for radiation protection; 3. Properties of radiations emitted from radionuclides; 4. Nuclear radiations from a user's perspective; 5. Ionising radiation detectors; 6. Radioactivity and countrate measurements and the presentation of results; 7. Industrial applications of radioisotopes and radiation; 8. Application of tracer technology to industry and the environment; 9. Radionuclides to protect the environment.

  7. Practical Applications of Radioactivity and Nuclear Radiations

    NASA Astrophysics Data System (ADS)

    Lowenthal, Gerhart; Airey, Peter

    2001-08-01

    1. Atoms, nuclides and radionuclides; 2. Units and standards for radioactivity and radiation dosimetry and rules for radiation protection; 3. Properties of radiations emitted from radionuclides; 4. Nuclear radiations from a user's perspective; 5. Ionising radiation detectors; 6. Radioactivity and countrate measurements and the presentation of results; 7. Industrial applications of radioisotopes and radiation; 8. Application of tracer technology to industry and the environment; 9. Radionuclides to protect the environment.

  8. Atomic magnetometer

    DOEpatents

    Schwindt, Peter; Johnson, Cort N.

    2012-07-03

    An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

  9. Radiation effects on structural materials

    SciTech Connect

    Ghoniem, N.M.

    1991-06-28

    This report discusses the following topics on the effect radiation has on thermonuclear reactor materials: Atomic Displacements; Microstructure Evolution; Materials Engineering, Mechanics, and Design; Research on Low-Activation Steels; and Research Motivated by Grant Support.

  10. Hot atom chemistry and radiopharmaceuticals

    SciTech Connect

    Krohn, Kenneth A.; Moerlein, Stephen M.; Link, Jeanne M.; Welch, Michael J.

    2012-12-19

    The chemical products made in a cyclotron target are a combined result of the chemical effects of the nuclear transformation that made the radioactive atom and the bulk radiolysis in the target. This review uses some well-known examples to understand how hot atom chemistry explains the primary products from a nuclear reaction and then how radiation chemistry is exploited to set up the optimal product for radiosynthesis. It also addresses the chemical effects of nuclear decay. There are important principles that are common to hot atom chemistry and radiopharmaceutical chemistry. Both emphasize short-lived radionuclides and manipulation of high specific activity nuclides. Furthermore, they both rely on radiochromatographic separation for identification of no-carrieradded products.

  11. Atoms in astronomy

    NASA Technical Reports Server (NTRS)

    Blanchard, P. A.

    1976-01-01

    Aspects of electromagnetic radiation and atomic physics needed for an understanding of astronomical applications are explored. Although intended primarily for teachers, this brochure is written so that it can be distributed to students if desired. The first section, Basic Topics, is suitable for a ninth-grade general science class; the style is simple and repetitive, and no mathematics or physics background is required. The second section, Intermediate and Advanced Topics, requires a knowledge of the material in the first section and assumes a generally higher level of achievement and motivation on the part of the student. These latter topics might fit well into junior-level physics, chemistry, or earth-science courses. Also included are a glossary, a list of references and teaching aids, class exercises, and a question and answer section.

  12. Atomic-level imaging, processing and characterization of semiconductor surfaces

    DOEpatents

    Kazmerski, L.L.

    1995-08-22

    A method for selecting and removing single specific atoms from a solid material surface uses photon biasing to break down bonds that hold the selected atom in the lattice and to reduce barrier effects that hold the atom from transferring to a probe. The photon bias is preferably light or other electromagnetic radiation with a wavelength and frequency that approximately matches the wave function of the target atom species to be removed to induce high energy, selective thermionic-like vibration. An electric field potential is then applied between the probe and the surface of the solid material to pull the atom out of the lattice and to transfer the atom to the probe. Different extrinsic atoms can be installed in the lattice sites that are vacated by the removed atoms by using a photon bias that resonates the extrinsic atom species, reversing polarity of the electric field, and blowing gas comprising the extrinsic atoms through a hollow catheter probe. 8 figs.

  13. Atomic-level imaging, processing and characterization of semiconductor surfaces

    DOEpatents

    Kazmerski, Lawrence L.

    1995-01-01

    A method for selecting and removing single specific atoms from a solid material surface uses photon biasing to break down bonds that hold the selected atom in the lattice and to reduce barrier effects that hold the atom from transferring to a probe. The photon bias is preferably light or other electromagnetic radiation with a wavelength and frequency that approximately matches the wave function of the target atom species to be removed to induce high energy, selective thermionic-like vibration. An electric field potential is then applied between the probe and the surface of the solid material to pull the atom out of the lattice and to transfer the atom to the probe. Different extrinsic atoms can be installed in the lattice sites that are vacated by the removed atoms by using a photon bias that resonates the extrinsic atom species, reversing polarity of the electric field, and blowing gas comprising the extrinsic atoms through a hollow catheter probe.

  14. An atomic model for neutral and singly ionized uranium

    NASA Technical Reports Server (NTRS)

    Maceda, E. L.; Miley, G. H.

    1979-01-01

    A model for the atomic levels above ground state in neutral, U(0), and singly ionized, U(+), uranium is described based on identified atomic transitions. Some 168 states in U(0) and 95 in U(+) are found. A total of 1581 atomic transitions are used to complete this process. Also discussed are the atomic inverse lifetimes and line widths for the radiative transitions as well as the electron collisional cross sections.

  15. Precision Excited State Lifetime Measurements for Atomic Parity Violation and Atomic Clocks

    NASA Astrophysics Data System (ADS)

    Sell, Jerry; Patterson, Brian; Gearba, Alina; Snell, Jeremy; Knize, Randy

    2016-05-01

    Measurements of excited state atomic lifetimes provide a valuable test of atomic theory, allowing comparisons between experimental and theoretical transition dipole matrix elements. Such tests are important in Rb and Cs, where atomic parity violating experiments have been performed or proposed, and where atomic structure calculations are required to properly interpret the parity violating effect. In optical lattice clocks, precision lifetime measurements can aid in reducing the uncertainty of frequency shifts due to the surrounding blackbody radiation field. We will present our technique for precisely measuring excited state lifetimes which employs mode-locked ultrafast lasers interacting with two counter-propagating atomic beams. This method allows the timing in the experiment to be based on the inherent timing stability of mode-locked lasers, while counter-propagating atomic beams provides cancellation of systematic errors due to atomic motion to first order. Our current progress measuring Rb excited state lifetimes will be presented along with future planned measurements in Yb.

  16. The atomic orbitals of the topological atom.

    PubMed

    Ramos-Cordoba, Eloy; Salvador, Pedro; Mayer, István

    2013-06-01

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These correspond to atomic hybrids that closely resemble the core and valence shells of the atom. The occupation numbers of the remaining effective orbitals are almost negligible, except for atoms with hypervalent character. In addition, the molecular orbitals of a calculation can be exactly expressed as a linear combination of this orthonormalized set of numerical atomic orbitals, and the Mulliken population analysis carried out on this basis set exactly reproduces the original QTAIM atomic populations of the atoms. Approximate expansion of the molecular orbitals over a much reduced set of orthogonal atomic basis functions can also be accomplished to a very good accuracy with a singular value decomposition procedure.

  17. "Bohr's Atomic Model."

    ERIC Educational Resources Information Center

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  18. Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca

    PubMed Central

    Khandaker, M. U.; Asaduzzaman, Kh.; Nawi, S. M.; Usman, A. R.; Amin, Y. M.; Daar, E.; Bradley, D. A.; Ahmed, H.; Okhunov, A. A.

    2015-01-01

    The environment of the Straits of Malacca receives pollution as a result of various industrial and anthropogenic sources, making systematic studies crucial in determining the prevailing water quality. Present study concerns concentrations of natural radionuclides and heavy metals in marine fish (Rastrelliger kanagurta) collected from the Straits of Malacca, since aquatic stock form an important source of the daily diet of the surrouding populace. Assessment was made of the concentrations of key indicator radionuclides (226Ra, 232Th, 40K) and heavy metals (As, Mn, Fe, Cr, Ni, Zn, Cu, Co, Sr, Al, Hg and Pb) together with various radiation indices linked to the consumption of seafish. The annual effective dose for all detected radionuclides for all study locations has been found to be within UNSCEAR acceptable limits as has the associated life-time cancer risk. The overall contamination of the sampled fish from heavy metals was also found to be within limits of tolerance. PMID:26075909

  19. Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca.

    PubMed

    Khandaker, M U; Asaduzzaman, Kh; Nawi, S M; Usman, A R; Amin, Y M; Daar, E; Bradley, D A; Ahmed, H; Okhunov, A A

    2015-01-01

    The environment of the Straits of Malacca receives pollution as a result of various industrial and anthropogenic sources, making systematic studies crucial in determining the prevailing water quality. Present study concerns concentrations of natural radionuclides and heavy metals in marine fish (Rastrelliger kanagurta) collected from the Straits of Malacca, since aquatic stock form an important source of the daily diet of the surrounding populace. Assessment was made of the concentrations of key indicator radionuclides (226Ra, 232Th, 40K) and heavy metals (As, Mn, Fe, Cr, Ni, Zn, Cu, Co, Sr, Al, Hg and Pb) together with various radiation indices linked to the consumption of seafish. The annual effective dose for all detected radionuclides for all study locations has been found to be within UNSCEAR acceptable limits as has the associated life-time cancer risk. The overall contamination of the sampled fish from heavy metals was also found to be within limits of tolerance.

  20. Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca.

    PubMed

    Khandaker, M U; Asaduzzaman, Kh; Nawi, S M; Usman, A R; Amin, Y M; Daar, E; Bradley, D A; Ahmed, H; Okhunov, A A

    2015-01-01

    The environment of the Straits of Malacca receives pollution as a result of various industrial and anthropogenic sources, making systematic studies crucial in determining the prevailing water quality. Present study concerns concentrations of natural radionuclides and heavy metals in marine fish (Rastrelliger kanagurta) collected from the Straits of Malacca, since aquatic stock form an important source of the daily diet of the surrounding populace. Assessment was made of the concentrations of key indicator radionuclides (226Ra, 232Th, 40K) and heavy metals (As, Mn, Fe, Cr, Ni, Zn, Cu, Co, Sr, Al, Hg and Pb) together with various radiation indices linked to the consumption of seafish. The annual effective dose for all detected radionuclides for all study locations has been found to be within UNSCEAR acceptable limits as has the associated life-time cancer risk. The overall contamination of the sampled fish from heavy metals was also found to be within limits of tolerance. PMID:26075909

  1. Atomic Energy Basics, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

    This booklet is part of the "Understanding the Atom Series," though it is a later edition and not included in the original set of 51 booklets. A basic survey of the principles of nuclear energy and most important applications are provided. These major topics are examined: matter has molecules and atoms, the atom has electrons, the nucleus,…

  2. The program RADLST (Radiation Listing)

    SciTech Connect

    Burrows, T.W.

    1988-02-29

    The program RADLST (Radiation Listing) is designed to calculate the nuclear and atomic radiations associated with the radioactive decay of nuclei. It uses as its primary input nuclear decay data in the Evaluated Nuclear Structure Data File (ENSDF) format. The code is written in FORTRAN 77 and, with a few exceptions, is consistent with the ANSI standard. 65 refs.

  3. Flame Radiation Measurements

    NASA Technical Reports Server (NTRS)

    Claus, R. W.; Humenik, F. M.; Neely, G. M.

    1983-01-01

    Spectral and total flame radiation measurements exhibited: (1) that radiant heat flux increases with vision combustor inlet air pressure; (2) the effect of fuel atomization characteristics on radiant heat flux; and (3) that a reduction in fuel hydrogen content produces a significant increase in radiant heat flux primarily at low combustor pressures.

  4. Adiabatic cooling of atoms by an intense standing wave

    NASA Astrophysics Data System (ADS)

    Chen, Jian; Story, J. G.; Tollett, J. J.; Hulet, Randall G.

    1992-08-01

    Lithium atoms channeled in the nodes of an intense standing-wave radiation field are cooled to near the recoil limit by adibatically reducing the radiation intensity. The final momentum distribution has a narrow component with a root-mean-squared momentum of 2ħk in one dimension, where ħk is the momentum of a radiation-field photon. The data are compared with the results of a Monte Carlo simulation using a two-level atom model. This process may be useful for cooling and increasing the phase-space density of atoms confined in a magnetic trap.

  5. Photonic, Electronic and Atomic Collisions

    NASA Astrophysics Data System (ADS)

    Fainstein, Pablo D.; Lima, Marco Aurelio P.; Miraglia, Jorge E.; Montenegro, Eduardo C.; Rivarola, Roberto D.

    2006-11-01

    Plenary. Electron collisions - past, present and future / J. W. McConkey. Collisions of slow highly charged ions with surfaces / J. Burgdörfer ... [et al.]. Atomic collisions studied with "reaction-microscopes" / R. Moshammer ... [et al.]. Rydberg atoms: a microscale laboratory for studying electron-molecule tnteractions / F. B. Dunning -- Collisions involvintg photons. Quantum control of photochemical reaction dynamics and molecular functions / M. Yamaki ... [et al.]. Manipulating and viewing Rydberg wavepackets / R. R. Jones. Angle-resolved photoelectrons as a probe of strong-field interactions / M. Vrakking. Ultracold Rydberg atoms in a structured environment / I. C. H. Liu and J. M. Rost. Synchrotron-radiation-based recoil ion momentum spectroscopy of laser cooled and trapped cesium atoms / L. H. Coutinho. Reconstruction of attosecond pulse trains / Y. Mairesse ... [et al.]. Selective excitation of metastable atomic states by Femto- and attosecond laser pulses / A. D. Kondorskiy. Accurate calculations of triple differential cross sections for double photoionization of the hygrogen molecule / W. Vanroose ... [et al.]. Double and triple photoionization of Li and Be / J. Colgan, M. S. Pindzola and F. Robicheaux. Few/many body dynamics in strong laser fields / J. Zanghellini and T. Brabec. Rescattering-induced effects in electron-atom scattering in the presence of a circularly polarized laser field / A. V. Flegel ... [et al.]. Multidimensional photoelectron spectroscopy / P. Lablanquie ... [et al.]. Few photon and strongly driven transitions in the XUV and beyond / P. Lambropoulos, L. A. A. Nikolopoulos and S. I. Themelis. Ionization dynamics of atomic clusters in intense laser pulses / U. Saalmann and J. M. Rost. On the second order autocorrelation of an XUV attosecond pulse train / E. P. Benis ... [et al.]. Evidence for rescattering in molecular dissociation / I. D. Williams ... [et al.]. Photoionizing ions using synchrotron radiation / R. Phaneuf. Photo double

  6. Radiation protection in space.

    PubMed

    Blakely, E A; Fry, R J

    1995-08-01

    The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in our knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared with previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers, including space travelers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space. PMID:7480625

  7. Atom-mirror entanglement via cavity dissipation

    NASA Astrophysics Data System (ADS)

    Li, Lingchao; Hu, Xiangming; Rao, Shi; Xu, Jun

    2015-05-01

    We present a cavity dissipation scheme to prepare a hybrid system of an atomic ensemble and a moving mirror in squeezed and entangled states. This scheme is based on four-wave mixing in the atoms and radiation pressure on the mirror, both of which combine to lead to Bogoliubov interactions of the atoms and the mirror with the cavity fields. Under adiabatic conditions, the cavity fields cause the hybrid Bogoliubov modes to evolve into the vacuum states, which correspond to the two-mode squeezed and entangled states. The dependence of the hybrid entanglement on the system parameters is also presented in and beyond the Bogoliubov interactions.

  8. High data rate atom interferometric device

    DOEpatents

    Biedermann, Grant; McGuinness, Hayden James Evans; Rakholia, Akash

    2015-07-21

    A light-pulse atomic interferometry (LPAI) apparatus is provided. The LPAI apparatus comprises a vessel, two sets of magnetic coils configured to magnetically confine an atomic vapor in two respective magneto-optical traps (MOTs) within the vessel when activated, and an optical system configured to irradiate the atomic vapor within the vessel with laser radiation that, when suitably tuned, can launch atoms previously confined in each of the MOTs toward the other MOT. In embodiments, the magnetic coils are configured to produce a magnetic field that is non-zero at the midpoint between the traps. In embodiments, the time-of-flight of the launched atoms from one MOT to the other is 12 ms or less. In embodiments, the MOTs are situated approximately 36 mm apart. In embodiments, the apparatus is configured to activate the magnetic coils according to a particular temporal magnetic field gradient profile.

  9. Radiation enteritis

    MedlinePlus

    Radiation enteropathy; Radiation-induced small bowel injury; Post-radiation enteritis ... Radiation therapy uses high-powered x-rays, particles, or radioactive seeds to kill cancer cells. The therapy ...

  10. Classical theory of thermal radiation from a solid.

    PubMed

    Guo, Wei

    2016-06-01

    In this work, a solid at a finite temperature is modeled as an ensemble of identical atoms, each of which moves around a lattice site inside an isotropic harmonic potential. The motion of one such atom is studied first. It is found that the atom moves like a time-dependent current density and, thus, can emit electromagnetic radiation. Since all the atoms are identical, they can radiate, too. The resultant radiation from the atoms is the familiar thermal radiation from the solid. After its general expression is obtained, the intensity of the thermal radiation is discussed for its properties, and specifically calculated in the low-temperature limit. Both atomic motion and radiation are formulated in the classical domain. PMID:27409442

  11. Ultracold-Atom Accelerometers

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    1995-01-01

    Proposed class of accelerometers and related motion sensors based on use of ultracold atoms as inertial components of motion transducers. Ultracold atoms supplant spring-and-mass components of older accelerometers. As used here, "ultracold atoms" means atoms with kinetic energies equivalent to temperatures equal to or less than 20 mK. Acclerometers essentially frictionless. Primary advantage high sensitivity.

  12. Neutral atom traps.

    SciTech Connect

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  13. 'Seeing' atoms: the crystallographic revolution.

    PubMed

    Schwarzenbach, Dieter

    2014-01-01

    Laue's experiment in 1912 of the diffraction of X-rays by crystals led to one of the most influential discoveries in the history of science: the first determinations of crystal structures, NaCl and diamond in particular, by W. L. Bragg in 1913. For the first time, the visualisation of the structure of matter at the atomic level became possible. X-ray diffraction provided a sort of microscope with atomic resolution, atoms became observable physical objects and their relative positions in space could be seen. All branches of science concerned with matter, solid-state physics, chemistry, materials science, mineralogy and biology, could now be firmly anchored on the spatial arrangement of atoms. During the ensuing 100 years, structure determination by diffraction methods has matured into an indispensable method of chemical analysis. We trace the history of the development of 'small-structure' crystallography (excepting macromolecular structures) in Switzerland. Among the pioneers figure Peter Debye and Paul Scherrer with powder diffraction, and Paul Niggli and his Zurich School with space group symmetry and geometrical crystallography. Diffraction methods were applied early on by chemists at the Universities of Bern and Geneva. By the 1970s, X-ray crystallography was firmly established at most Swiss Universities, directed by full professors. Today, chemical analysis by structure determination is the task of service laboratories. However, the demand of diffraction methods to solve problems in all disciplines of science is still increasing and powerful radiation sources and detectors are being developed in Switzerland and worldwide. PMID:24801690

  14. Radiation in Particle Simulations

    SciTech Connect

    More, R; Graziani, F; Glosli, J; Surh, M

    2010-11-19

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of megabars to thousands of gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known. The second method expands the electromagnetic field in normal modes (planewaves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion. The third method is a hybrid molecular dynamics/Monte Carlo (MD/MC) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions. The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc. This approach is inspired by the virial expansion method of equilibrium statistical mechanics. Using a combination of these methods we believe it is possible to do atomic-scale particle simulations of

  15. Computer Model Of Fragmentation Of Atomic Nuclei

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Townsend, Lawrence W.; Tripathi, Ram K.; Norbury, John W.; KHAN FERDOUS; Badavi, Francis F.

    1995-01-01

    High Charge and Energy Semiempirical Nuclear Fragmentation Model (HZEFRG1) computer program developed to be computationally efficient, user-friendly, physics-based program for generating data bases on fragmentation of atomic nuclei. Data bases generated used in calculations pertaining to such radiation-transport applications as shielding against radiation in outer space, radiation dosimetry in outer space, cancer therapy in laboratories with beams of heavy ions, and simulation studies for designing detectors for experiments in nuclear physics. Provides cross sections for production of individual elements and isotopes in breakups of high-energy heavy ions by combined nuclear and Coulomb fields of interacting nuclei. Written in ANSI FORTRAN 77.

  16. From carbon nanotubes to carbon atomic chains

    NASA Astrophysics Data System (ADS)

    Casillas García, Gilberto; Zhang, Weijia; José-Yacamán, Miguel

    2010-10-01

    Carbyne is a linear allotrope of carbon. It is formed by a linear arrangement of carbon atoms with sp-hybridization. We present a reliable and reproducible experiment to obtain these carbon atomic chains using few-layer-graphene (FLG) sheets and a HRTEM. First the FLG sheets were synthesized from worm-like exfoliated graphite and then drop-casted on a lacey-carbon copper grid. Once in the TEM, two holes are opened near each other in a FLG sheet by focusing the electron beam into a small spot. Due to the radiation, the carbon atoms rearrange themselves between the two holes and form carbon fibers. The beam is concentrated on the carbon fibers in order excite the atoms and induce a tension until multi wall carbon nanotube (MWCNT) is formed. As the radiation continues the MWCNT breaks down until there is only a single wall carbon nanotube (SWCNT). Then, when the SWCNT breaks, an atomic carbon chain is formed, lasts for several seconds under the radiation and finally breaks. This demonstrates the stability of this carbon structure.

  17. The Harnessed Atom: Nuclear Energy & Electricity.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Nuclear Energy Office.

    This document is part of a nuclear energy curriculum designed for grades six through eight. The complete kit includes a written text, review exercises, activities for the students, and a teachers guide. The 19 lessons in the curriculum are divided into four units including: (1) "Energy and Electricity"; (2) "Understanding Atoms and Radiation"; (3)…

  18. History and Organizations for Radiological Protection

    PubMed Central

    2016-01-01

    International Commission on Radiological Protection (ICRP), an independent international organization established in 1925, develops, maintains, and elaborates radiological protection standards, legislation, and guidelines. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) provides scientific evidence. World Health Organization (WHO) and International Atomic Energy Agency (IAEA) utilise the ICRP recommendations to implement radiation protection in practice. Finally, radiation protection agencies in each country adopt the policies, and adapt them to each situation. In Korea, Nuclear Safety and Security Commission is the governmental body for nuclear safety regulation and Korea Institute of Nuclear Safety is a public organization for technical support and R&D in nuclear safety and radiation protection. PMID:26908987

  19. History and Organizations for Radiological Protection.

    PubMed

    Kang, Keon Wook

    2016-02-01

    International Commission on Radiological Protection (ICRP), an independent international organization established in 1925, develops, maintains, and elaborates radiological protection standards, legislation, and guidelines. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) provides scientific evidence. World Health Organization (WHO) and International Atomic Energy Agency (IAEA) utilise the ICRP recommendations to implement radiation protection in practice. Finally, radiation protection agencies in each country adopt the policies, and adapt them to each situation. In Korea, Nuclear Safety and Security Commission is the governmental body for nuclear safety regulation and Korea Institute of Nuclear Safety is a public organization for technical support and R&D in nuclear safety and radiation protection.

  20. Radiation-induced disease.

    PubMed

    Bobrow, M

    1993-01-01

    The term radiation covers a wide spectrum of forms of energy, most of which have at one stage or another been suspected of causing human ill health. In general, study of the effects of radiation on health involves a mix of scientific disciplines, from population epidemiology to physics, which are seldom if ever found in a single scientist. As a result, interdisciplinary communication is of the utmost importance, and is a potent source of misunderstanding and misinformation. The forms of radiation which have been most specifically associated with health effects include ionizing and ultraviolet radiation. Claimed effects of electromagnetic and microwave radiation (excluding thermal effects) are too indefinite for detailed consideration. Ionizing radiation is a well-documented mutagen, which clearly causes cancers in humans, and human exposure has been increased by atomic weapons testing and medical and industrial uses of radioactivity. There is also a growing awareness of the possible role of some types of natural radiation, such as radon, in causing disease. Ultraviolet radiation is also associated with cancers, and is suspected of involvement in the increasing incidence of skin cancers in European populations. Factors thought to underlie recent changes in exposure to these mutagens are discussed.

  1. Slow metastable atomic hydrogen beam by optical pumping

    NASA Astrophysics Data System (ADS)

    Harvey, K. C.

    1982-05-01

    A beam source of atomic hydrogen is described which produces metastable atoms in the 2S1/2 state by optical pumping. A beam flux of 1016 atoms/s is generated in the ground state. The atoms in the beam pass in front of a lamp producing Lyman-β (1026 Å) radiation, where some of them are excited to the 3P level and cascade with a branching ratio of 12% to the 2S1/2 state. The number of metastable atoms produced is measured by quenching them with an electric field and detecting the emitted Lyman-α (1216 Å) radiation. Beams of 106 metastable atoms/s were obtained. Using the Bethe-Lamb theory for the quenching process, a metastable beam effective temperature of 100 K was measured.

  2. Atomic Fuel, Understanding the Atom Series. Revised.

    ERIC Educational Resources Information Center

    Hogerton, John F.

    This publication is part of the "Understanding the Atom" series. Complete sets of the series are available free to teachers, schools, and public librarians who can make them available for reference or use by groups. Among the topics discussed are: What Atomic Fuel Is; The Odyssey of Uranium; Production of Uranium; Fabrication of Reactor Fuel…

  3. Resonant quantum transitions in trapped antihydrogen atoms.

    PubMed

    Amole, C; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Capra, A; Cesar, C L; Charlton, M; Deller, A; Donnan, P H; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Isaac, C A; Jonsell, S; Kurchaninov, L; Little, A; Madsen, N; McKenna, J T K; Menary, S; Napoli, S C; Nolan, P; Olchanski, K; Olin, A; Pusa, P; Rasmussen, C Ø; Robicheaux, F; Sarid, E; Shields, C R; Silveira, D M; Stracka, S; So, C; Thompson, R I; van der Werf, D P; Wurtele, J S

    2012-03-07

    The hydrogen atom is one of the most important and influential model systems in modern physics. Attempts to understand its spectrum are inextricably linked to the early history and development of quantum mechanics. The hydrogen atom's stature lies in its simplicity and in the accuracy with which its spectrum can be measured and compared to theory. Today its spectrum remains a valuable tool for determining the values of fundamental constants and for challenging the limits of modern physics, including the validity of quantum electrodynamics and--by comparison with measurements on its antimatter counterpart, antihydrogen--the validity of CPT (charge conjugation, parity and time reversal) symmetry. Here we report spectroscopy of a pure antimatter atom, demonstrating resonant quantum transitions in antihydrogen. We have manipulated the internal spin state of antihydrogen atoms so as to induce magnetic resonance transitions between hyperfine levels of the positronic ground state. We used resonant microwave radiation to flip the spin of the positron in antihydrogen atoms that were magnetically trapped in the ALPHA apparatus. The spin flip causes trapped anti-atoms to be ejected from the trap. We look for evidence of resonant interaction by comparing the survival rate of trapped atoms irradiated with microwaves on-resonance to that of atoms subjected to microwaves that are off-resonance. In one variant of the experiment, we detect 23 atoms that survive in 110 trapping attempts with microwaves off-resonance (0.21 per attempt), and only two atoms that survive in 103 attempts with microwaves on-resonance (0.02 per attempt). We also describe the direct detection of the annihilation of antihydrogen atoms ejected by the microwaves.

  4. Nanotechnology in radiation oncology.

    PubMed

    Wang, Andrew Z; Tepper, Joel E

    2014-09-10

    Nanotechnology, the manipulation of matter on atomic and molecular scales, is a relatively new branch of science. It has already made a significant impact on clinical medicine, especially in oncology. Nanomaterial has several characteristics that are ideal for oncology applications, including preferential accumulation in tumors, low distribution in normal tissues, biodistribution, pharmacokinetics, and clearance, that differ from those of small molecules. Because these properties are also well suited for applications in radiation oncology, nanomaterials have been used in many different areas of radiation oncology for imaging and treatment planning, as well as for radiosensitization to improve the therapeutic ratio. In this article, we review the unique properties of nanomaterials that are favorable for oncology applications and examine the various applications of nanotechnology in radiation oncology. We also discuss the future directions of nanotechnology within the context of radiation oncology.

  5. Nanotechnology in Radiation Oncology

    PubMed Central

    Wang, Andrew Z.; Tepper, Joel E.

    2014-01-01

    Nanotechnology, the manipulation of matter on atomic and molecular scales, is a relatively new branch of science. It has already made a significant impact on clinical medicine, especially in oncology. Nanomaterial has several characteristics that are ideal for oncology applications, including preferential accumulation in tumors, low distribution in normal tissues, biodistribution, pharmacokinetics, and clearance, that differ from those of small molecules. Because these properties are also well suited for applications in radiation oncology, nanomaterials have been used in many different areas of radiation oncology for imaging and treatment planning, as well as for radiosensitization to improve the therapeutic ratio. In this article, we review the unique properties of nanomaterials that are favorable for oncology applications and examine the various applications of nanotechnology in radiation oncology. We also discuss the future directions of nanotechnology within the context of radiation oncology. PMID:25113769

  6. Lecture on Thermal Radiation

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.

    2006-01-01

    This lecture will cover solar thermal radiation, particularly as it relates to the high energy solar processes that are the subject of this summer school. After a general review of thermal radiation from the Sun and a discussion of basic definitions, the various emission and absorption mechanisms will be described including black-body emission, bremsstrahlung, free-bound, and atomic line emissions of all kinds. The bulk of the time will be spent discussing the observational characteristics of thermal flare plasma and what can be learned about the flare energy release process from observations of the thermal radiation at all wavelengths. Information that has been learned about the morphology, temperature distribution, and composition of the flare plasma will be presented. The energetics of the thermal flare plasma will be discussed in relation to the nonthermal energy of the particles accelerated during the flare. This includes the total energy, the radiated and conductive cooling processes, and the total irradiated energy.

  7. [Genetic effects of radiation].

    PubMed

    Nakamura, Nori

    2012-03-01

    This paper is a short review of genetic effect of radiation. This includes methods and results of a large-scale genetic study on specific loci in mice and of various studies in the offspring of atomic-bomb survivors. As for the latter, there is no results obtained which suggest the effect of parental exposure to radiation. Further, in recent years, studies are conducted to the offspring born to parents who were survivors of childhood cancers. In several reports, the mean gonad dose is quite large whereas in most instances, the results do not indicate genetic effect following parental exposure to radiation. Possible reasons for the difficulties in detecting genetic effect of radiation are discussed. PMID:22514926

  8. PHYSICS: Toward Atom Chips.

    PubMed

    Fortágh, József; Zimmermann, Claus

    2005-02-11

    As a novel approach for turning the peculiar features of quantum mechanics into practical devices, researchers are investigating the use of ultracold atomic clouds above microchips. Such "atom chips" may find use as sensitive probes for gravity, acceleration, rotation, and tiny magnetic forces. In their Perspective, Fortagh and Zimmermann discuss recent advances toward creating atom chips, in which current-carrying conductors in the chips create magnetic microtraps that confine the atomic clouds. Despite some intrinsic limits to the performance of atom chips, existing technologies are capable of producing atom chips, and many possibilities for their construction remain to be explored.

  9. Atom probe tomography

    SciTech Connect

    Miller, M.K.; Forbes, R.G.

    2009-06-15

    This introductory tutorial describes the technique of atom probe tomography for materials characterization at the atomic level. The evolution of the technique from the initial atom probe field ion microscope to today's state-of-the-art three dimensional atom probe is outlined. An introduction is presented on the basic physics behind the technique, the operation of the instrument, and the reconstruction of the three-dimensional data. The common methods for analyzing the three-dimensional atom probe data, including atom maps, isoconcentration surfaces, proximity histograms, maximum separation methods, and concentration frequency distributions, are described.

  10. Epidemiology of accidental radiation exposures.

    PubMed Central

    Cardis, E

    1996-01-01

    Much of the information on the health effects of radiation exposure available to date comes from long-term studies of the atomic bombings in Hiroshima and Nagasaki. Accidental exposures, such as those resulting from the Chernobyl and Kyshtym accidents, have as yet provided little information concerning health effects of ionizing radiation. This paper will present the current state of our knowledge concerning radiation effects, review major large-scale accidental radiation exposures, and discuss information that could be obtained from studies of accidental exposures and the types of studies that are needed. PMID:8781398

  11. External and internal radiation exposure of herbal plants used in Egypt

    NASA Astrophysics Data System (ADS)

    Ahmed, Fawzia; Daif, Manal M.; El-Masry, N. M.; Abo-Elmagd, M.

    2010-01-01

    Herbs in Egypt are imported from different countries and widely used in different forms. Owing to their different origins, the measured radioactivity levels show a broad range. For example, the radium concentrations in the studied herbs ranged from 7.71±0.25 Bq/kg in green tea to 115.08±0.49 Bq/kg in gawafa. 137Cs concentrations were found to be quite different from one herb to another, ranging from below the minimum detectable limit to 12.62±0.42 Bq/kg. Some values are much greater than the UNSCEAR reported values for grain products and vegetables. The external exposure and the uptake of naturally occurring radionuclides were studied in terms of the annual effective absorbed dose and the annual ingestion dose, respectively. The herb store workers are externally exposed due to natural radiation in the herbs. The annual effective absorbed dose was calculated as 282.8 μSv for tilia, a dose which is over half the total annual effective dose due to terrestrial radiation (which is 410 μSv). Thus, it is potentially possible to accumulate excess doses from all herbs in the store which constitute a health hazard to the workers. For internal exposure, assuming a 1 kg/year annual intake for each herb, the annual ingestion doses are lower than the global value and can be further diminished if herbs with lower concentrations of radionuclides are consumed.

  12. Presenting the Bohr Atom.

    ERIC Educational Resources Information Center

    Haendler, Blanca L.

    1982-01-01

    Discusses the importance of teaching the Bohr atom at both freshman and advanced levels. Focuses on the development of Bohr's ideas, derivation of the energies of the stationary states, and the Bohr atom in the chemistry curriculum. (SK)

  13. Atomic oxygen effects on refractory materials

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    1990-01-01

    Atomic oxygen in LEO may have undesirable effects on exposed refractory materials, such as are proposed for nuclear reactors in orbit, high temperature radiators, solar dynamic collectors, etc. Time-resolved measurement of the volatile efflux from such materials at high temperatures is being done in an ultrahigh vacuum atomic oxygen ion beam facility. Results of measurements of the efflux of volatile oxides of molybdenum and niobium-1 percent zirconium at temperatures as high as 1550 K are presented, along with a discussion of the roles of adsorption, desorption, and diffusion in atomic oxygen reactions on surfaces at high temperatures. The dependence of reaction rates for certain materials on the energy of the incident atomic oxygen beam will be emphasized.

  14. Atomic vapor spectroscopy in integrated photonic structures

    SciTech Connect

    Ritter, Ralf; Kübler, Harald; Pfau, Tilman; Löw, Robert; Gruhler, Nico; Pernice, Wolfram

    2015-07-27

    We investigate an integrated optical chip immersed in atomic vapor providing several waveguide geometries for spectroscopy applications. The narrow-band transmission through a silicon nitride waveguide and interferometer is altered when the guided light is coupled to a vapor of rubidium atoms via the evanescent tail of the waveguide mode. We use grating couplers to couple between the waveguide mode and the radiating wave, which allow for addressing arbitrary coupling positions on the chip surface. The evanescent atom-light interaction can be numerically simulated and shows excellent agreement with our experimental data. This work demonstrates a next step towards miniaturization and integration of alkali atom spectroscopy and provides a platform for further fundamental studies of complex waveguide structures.

  15. Atomizing nozzle and process

    DOEpatents

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1992-06-30

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  16. Atoms in Action

    SciTech Connect

    2009-01-01

    This movie produced with Berkeley Lab's TEAM 0.5 microscope shows the growth of a hole and the atomic edge reconstruction in a graphene sheet. An electron beam focused to a spot on the sheet blows out the exposed carbon atoms to make the hole. The carbon atoms then reposition themselves to find a stable configuration. http://newscenter.lbl.gov/press-releases/2009/03/26/atoms-in-action/

  17. Atomizing nozzle and process

    DOEpatents

    Anderson, I.E.; Figliola, R.S.; Molnar, H.M.

    1993-07-20

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  18. Comparison between dressed-atom and bare-atom pictures in laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Berman, P. R.; Salomaa, Rainer

    1982-05-01

    The theory of the interaction between radiation fields and atoms as applied to laser spectroscopy can be approached using either a bare-atom picture (BAP) or dressed-atom picture (DAP). In the BAP, the basis states are those of the free atoms and free field while, in the DAP, the basis states encompass some part of the atom-field interaction. The theory of saturation spectroscopy in three-level systems is discussed using both approaches. Whereas calculations are usually more easily done using the BAP, one can gain useful insight into the underlying physical processes from the DAP. Moreover, when the radiation field strengths (in frequency units) are larger than the relaxation rates in the problem, the DAP equations simplify considerably and lead to line-shape expressions which may be given a simple interpretation. The DAP is used to obtain resonance conditions for traveling-wave fields interacting with three- and four-level atoms and for a standing-wave saturator and traveling-wave probe interacting with a three-level atom. In addition, the DAP is applied to several problems involving optical coherent transients. A comparison is made between the various advantages of the BAP and DAP and an interesting duality between the two approaches is noted.

  19. Adaptive atom-optics in atom interferometry

    NASA Astrophysics Data System (ADS)

    Marable, M. L.; Savard, T. A.; Thomas, J. E.

    1997-02-01

    We suggest a general technique for creating virtual atom-optical elements which are adaptive. The shape and position of these elements is determined by the frequency distribution for optical fields which induce transitions in a high gradient potential. This adaptive method is demonstrated in an all-optical atom interferometer, by creating either a variable optical slit or a variable optical grating which is scanned across the atomic spatial patterns to measure the fringes. This method renders mechanical motion of the interferometer elements unnecessary.

  20. Atomic Spectra Database (ASD)

    National Institute of Standards and Technology Data Gateway

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  1. The Nature of Atoms.

    ERIC Educational Resources Information Center

    Holden, Alan

    This monograph was written for the purpose of presenting physics to college students who are not preparing for careers in physics. It deals with the nature of atoms, and treats the following topics: (1) the atomic hypothesis, (2) the chemical elements, (3) models of an atom, (4) a particle in a one-dimensional well, (5) a particle in a central…

  2. Images of Atoms.

    ERIC Educational Resources Information Center

    Wright, Tony

    2003-01-01

    Recommends using a simple image, such as the fuzzy atom ball to help students develop a useful understanding of the molecular world. Explains that the image helps students easily grasp ideas about atoms and molecules and leads naturally to more advanced ideas of atomic structure, chemical bonding, and quantum physics. (Author/NB)

  3. Fraunhofer effect atomic absorption spectrometry.

    PubMed

    Rust, Jennifer A; Nóbrega, Joaquim A; Calloway, Clifton P; Jones, Bradley T

    2005-02-15

    The dark lines in the solar spectrum were discovered by Wollaston and cataloged by Fraunhofer in the early days of the 19th century. Some years later, Kirchhoff explained the appearance of the dark lines: the sun was acting as a continuum light source and metals in the ground state in its atmosphere were absorbing characteristic narrow regions of the spectrum. This discovery eventually spawned atomic absorption spectrometry, which became a routine technique for chemical analysis in the mid-20th century. Laboratory-based atomic absorption spectrometers differ from the original observation of the Fraunhofer lines because they have always employed a separate light source and atomizer. This article describes a novel atomic absorption device that employs a single source, the tungsten coil, as both the generator of continuum radiation and the atomizer of the analytes. A 25-microL aliquot of sample is placed on the tungsten filament removed from a commercially available 150-W light bulb. The solution is dried and ashed by applying low currents to the coil in a three-step procedure. Full power is then applied to the coil for a brief period. During this time, the coil produces white light, which may be absorbed by any metals present in the atomization cloud produced by the sample. A high-resolution spectrometer with a charge-coupled device detector monitors the emission spectrum of the coil, which includes the dark lines from the metals. Detection limits are reported for seven elements: 5 pg of Ca (422.7 nm); 2 ng of Co (352.7 nm); 200 pg of Cr (425.4 nm); 7 pg of Sr (460.7 nm); 100 pg of Yb (398.8 nm); 500 pg of Mn (403.1 nm); and 500 pg of K (404.4 nm). Simultaneous multielement analyses are possible within a 4-nm spectral window. The relative standard deviations for the seven metals are below 8% for all metals except for Ca (10.7%), which was present in the blank at measurable levels. Analysis of a standard reference material (drinking water) resulted in a mean percent

  4. Radiation Therapy

    MedlinePlus

    Radiation therapy is a cancer treatment. It uses high doses of radiation to kill cancer cells and stop them from ... half of all cancer patients receive it. The radiation may be external, from special machines, or internal, ...

  5. Radiation Therapy

    MedlinePlus

    ... people who have radiation therapy may feel more tired than usual, not feel hungry, or lose their ... of radiation therapy include: Fatigue. Fatigue, or feeling tired, is the most common side effect of radiation ...

  6. Radiation therapy

    MedlinePlus

    ... Because radiation is most harmful to quickly growing cells, radiation therapy damages cancer cells more than normal cells. ... cells from growing and dividing, and leads to cell death. Radiation therapy is used to fight many types of ...

  7. Autoantibodies and immunoglobulins among atomic bomb survivors

    SciTech Connect

    Fujiwara, Saeko; Akahoshi, Masazumi; Kodama, Kazunori; Shimaoka, Katsutaro; Akiyama, Mitoshi; Carter, R.L.; Yamakido, Michio

    1994-01-01

    The purpose of this study was to determine if exposure to atomic bomb radiation affects immune responsiveness, such as the occurrence of autoantibodies and levels of immunoglobulins. Rheumatoid factor, antinuclear antibody, antithyroglobulin antibody, anti-thyroid-microsomal antibody and immunoglobulin levels (IgG, IgM, IgA and IgE) were measured among 2,061 individuals exposed to atomic bomb radiation in Hiroshima and Nagasaki whose estimated doses ranged from 0 to 5.6 Gy. The prevalence and titers of rheumatoid factor were found to be increased in the individuals exposed to higher radiation doses. The IgA level in females and the IgM level in both sexes increased as radiation dose increased, although the effects of radiation exposure were not large. No effect of radiation was found on the prevalence of antinuclear antibody, antithyroglobulin antibody and anti-thyroid-microsomal antibody or on the levels of IgG and IgE. 32 refs., 2 figs., 3 tabs.

  8. Atmospheric radiation

    SciTech Connect

    Harshvardhan, M.R. )

    1991-01-01

    Studies of atmospheric radiative processes are summarized for the period 1987-1990. Topics discussed include radiation modeling; clouds and radiation; radiative effects in dynamics and climate; radiation budget and aerosol effects; and gaseous absorption, particulate scattering and surface reflection. It is concluded that the key developments of the period are a defining of the radiative forcing to the climate system by trace gases and clouds, the recognition that cloud microphysics and morphology need to be incorporated not only into radiation models but also climate models, and the isolation of a few important unsolved theoretical problems in atmospheric radiation.

  9. Single atom electrochemical and atomic analytics

    NASA Astrophysics Data System (ADS)

    Vasudevan, Rama

    In the past decade, advances in electron and scanning-probe based microscopies have led to a wealth of imaging and spectroscopic data with atomic resolution, yielding substantial insight into local physics and chemistry in a diverse range of systems such as oxide catalysts, multiferroics, manganites, and 2D materials. However, typical analysis of atomically resolved images is limited, despite the fact that image intensities and distortions of the atoms from their idealized positions contain unique information on the physical and chemical properties inherent to the system. Here, we present approaches to data mine atomically resolved images in oxides, specifically in the hole-doped manganite La5/8Ca3/8MnO3, on epitaxial films studied by in-situ scanning tunnelling microscopy (STM). Through application of bias to the STM tip, atomic-scale electrochemistry is demonstrated on the manganite surface. STM images are then further analyzed through a suite of algorithms including 2D autocorrelations, sliding window Fourier transforms, and others, and can be combined with basic thermodynamic modelling to reveal relevant physical and chemical descriptors including segregation energies, existence and strength of atomic-scale diffusion barriers, surface energies and sub-surface chemical species identification. These approaches promise to provide tremendous insights from atomically resolved functional imaging, can provide relevant thermodynamic parameters, and auger well for use with first-principles calculations to yield quantitative atomic-level chemical identification and structure-property relations. This research was sponsored by the Division of Materials Sciences and Engineering, BES, DOE. Research was conducted at the Center for Nanophase Materials Sciences, which also provided support and is a DOE Office of Science User Facility.

  10. Assurance Against Radiation Effects on Electronics

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.

    2004-01-01

    Contents include the following: The Space Radiation Environment. The Effects on Electronics. The Environment in Action. NASA Approaches to Commercial Electronics: the mission mix, flight projects, and proactive research. Final Thoughts: atomic interactions, direct ionization, interaction with nucleus.

  11. Radiation field associated with Hiroshima and Nagasaki

    SciTech Connect

    Loewe, W.E.

    1984-08-01

    Accuracy of dosimetric estimates can determine the value of the atomic bomb survivor experience in establishing radiation risks. The status of a major revision of this dosimetry, initiated in 1980, is assessed. 3 references, 6 figures.

  12. Multilevel Atomic Coherent States and Atomic Holomorphic Representation

    NASA Technical Reports Server (NTRS)

    Cao, Chang-Qi; Haake, Fritz

    1996-01-01

    The notion of atomic coherent states is extended to the case of multilevel atom collective. Based on atomic coherent states, a holomorphic representation for atom collective states and operators is defined. An example is given to illustrate its application.

  13. STS-8 atomic oxygen effects experiment

    NASA Technical Reports Server (NTRS)

    Visentine, J. T.; Leger, L. J.; Kuminecz, J. F.; Spiker, I. K.

    1985-01-01

    A flight experiment was performed on the eighth Space Shuttle mission to measure reaction of surfaces with atomic oxygen in the low earth orbital environment. More than 300 individual samples were exposed to ram (normal to surface) conditions for 41.75 hr leading to a total atomic oxygen fluence of 3.5 x 10 to the 20th atoms/sq cm. Reaction rates for surface recession measured primarily by mass change of several organic films were in the range of 3.0 x 10 to the -24th cu cm/atom, and less than 5 x 10 to the -26th cu cm/atom for Teflon. Effects of parameters such as temperature and solar radiation were assessed, as was the importance of atmospheric ionic species on surface recession. In an experiment performed on the fifth Space Shuttle flight, no temperature dependence of reaction rate for the organic films studied was found in the temperature range of 25 to 125 C. Preliminary findings indicate that the reactivity of organic films is not affected by temperature (in the range of 65 to 125 C), solar radiation, or ionic species. Significant surface morphology changes led to a carpet-like appearance also consistent with previous findings.

  14. Coherent manipulation of a solid-state artificial atom with few photons.

    PubMed

    Giesz, V; Somaschi, N; Hornecker, G; Grange, T; Reznychenko, B; De Santis, L; Demory, J; Gomez, C; Sagnes, I; Lemaître, A; Krebs, O; Lanzillotti-Kimura, N D; Lanco, L; Auffeves, A; Senellart, P

    2016-06-17

    In a quantum network based on atoms and photons, a single atom should control the photon state and, reciprocally, a single photon should allow the coherent manipulation of the atom. Both operations require controlling the atom environment and developing efficient atom-photon interfaces, for instance by coupling the natural or artificial atom to cavities. So far, much attention has been drown on manipulating the light field with atomic transitions, recently at the few-photon limit. Here we report on the reciprocal operation and demonstrate the coherent manipulation of an artificial atom by few photons. We study a quantum dot-cavity system with a record cooperativity of 13. Incident photons interact with the atom with probability 0.95, which radiates back in the cavity mode with probability 0.96. Inversion of the atomic transition is achieved for 3.8 photons on average, showing that our artificial atom performs as if fully isolated from the solid-state environment.

  15. Calculation of tin atomic data and plasma properties.

    SciTech Connect

    Morozov, V.; Tolkach, V.; Hassanein, A.

    2005-08-26

    This report reviews the major methods and techniques we use in generating basic atomic and plasma properties relevant to extreme ultraviolet (EUV) lithography applications. The basis of the work is the calculation of the atomic energy levels, transitions probabilities, and other atomic data by various methods, which differ in accuracy, completeness, and complication. Later on, we calculate the populations of atomic levels and ion states in plasmas by means of the collision-radiation equilibrium (CRE) model. The results of the CRE model are used as input to the thermodynamic functions, such as pressure and temperature from the internal energy and density (equation of state), electric resistance, thermal conduction, and other plasma properties. In addition, optical coefficients, such as emission and absorption coefficients, are generated to resolve a radiation transport equation (RTE). The capabilities of our approach are demonstrated by generating the required atomic and plasma properties for tin ions and plasma within the EUV region near 13.5 nm.

  16. Two photon excitation of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Pindzola, M. S.

    1977-01-01

    A standard perturbation expansion in the atom-radiation field interaction is used to calculate the two photon excitation cross section for 1s(2) 2s(2) 2p(4) p3 to 1s(2) 2s(2) 2p(3) (s4) 3p p3 transition in atomic oxygen. The summation over bound and continuum intermediate states is handled by solving the equivalent inhomogeneous differential equation. Exact summation results differ by a factor of 2 from a rough estimate obtained by limiting the intermediate state summation to one bound state. Higher order electron correlation effects are also examined.

  17. Pelvic radiation - discharge

    MedlinePlus

    Radiation of the pelvis - discharge; Cancer treatment - pelvic radiation; Prostate cancer - pelvic radiation; Ovarian cancer - pelvic radiation; Cervical cancer - pelvic radiation; Uterine cancer - pelvic radiation; Rectal cancer - ...

  18. Cardiovascular complications of radiation exposure.

    PubMed

    Finch, William; Shamsa, Kamran; Lee, Michael S

    2014-01-01

    The cardiovascular sequelae of radiation exposure are an important cause of morbidity and mortality following radiation therapy for cancer, as well as after exposure to radiation after atomic bombs or nuclear accidents. In the United States, most of the data on radiation-induced heart disease (RIHD) come from patients treated with radiation therapy for Hodgkin disease and breast cancer. Additionally, people exposed to radiation from the atomic bombs in Hiroshima and Nagasaki, Japan, and the Chernobyl, Ukraine, nuclear accident have an increased risk of cardiovascular disease. The total dose of radiation, as well as the fractionation of the dose, plays an important role in the development of RIHD. All parts of the heart are affected, including the pericardium, vasculature, myocardium, valves, and conduction system. The mechanism of injury is complex, but one major mechanism is injury to endothelium in both the microvasculature and coronary arteries. This likely also contributes to damage and fibrosis within the myocardium. Additionally, various inflammatory and profibrotic cytokines contribute to injury. Diagnosis and treatment are not significantly different from those for conventional cardiovascular disease; however, screening for heart disease and lifelong cardiology follow-up is essential in patients with past radiation exposure.

  19. Cardiovascular complications of radiation exposure.

    PubMed

    Finch, William; Shamsa, Kamran; Lee, Michael S

    2014-01-01

    The cardiovascular sequelae of radiation exposure are an important cause of morbidity and mortality following radiation therapy for cancer, as well as after exposure to radiation after atomic bombs or nuclear accidents. In the United States, most of the data on radiation-induced heart disease (RIHD) come from patients treated with radiation therapy for Hodgkin disease and breast cancer. Additionally, people exposed to radiation from the atomic bombs in Hiroshima and Nagasaki, Japan, and the Chernobyl, Ukraine, nuclear accident have an increased risk of cardiovascular disease. The total dose of radiation, as well as the fractionation of the dose, plays an important role in the development of RIHD. All parts of the heart are affected, including the pericardium, vasculature, myocardium, valves, and conduction system. The mechanism of injury is complex, but one major mechanism is injury to endothelium in both the microvasculature and coronary arteries. This likely also contributes to damage and fibrosis within the myocardium. Additionally, various inflammatory and profibrotic cytokines contribute to injury. Diagnosis and treatment are not significantly different from those for conventional cardiovascular disease; however, screening for heart disease and lifelong cardiology follow-up is essential in patients with past radiation exposure. PMID:25290729

  20. Excited-state collisions of trapped 85Rb atoms

    NASA Astrophysics Data System (ADS)

    Hoffmann, D.; Feng, P.; Williamson, R. S., III; Walker, T.

    1992-08-01

    We descrbe a new method for measuring excited-state collisions between optically trapped atoms. With this method, trap-loss collision rates are deduced from the loading behavior of clouds of trapped atoms in the regime where radiation trapping limits the atom density. Our measurements indicate that 85Rb trap-loss collisions occur at significantly smaller rates than expected both from previous work on Cs and from recent models. In addition, the dependence of the trap-loss collisions on the frequency of the light used to excite the atom pairs is also different from that of Cs, suggesting that assumptions about the dynamics in these models need modification.

  1. Uranium isotopes quantitatively determined by modified method of atomic absorption spectrophotometry

    NASA Technical Reports Server (NTRS)

    Lee, G. H.

    1967-01-01

    Hollow-cathode discharge tubes determine the quantities of uranium isotopes in a sample by using atomic absorption spectrophotometry. Dissociation of the uranium atoms allows a large number of ground state atoms to be produced, absorbing the incident radiation that is different for the two major isotopes.

  2. Single atom microscopy.

    PubMed

    Zhou, Wu; Oxley, Mark P; Lupini, Andrew R; Krivanek, Ondrej L; Pennycook, Stephen J; Idrobo, Juan-Carlos

    2012-12-01

    We show that aberration-corrected scanning transmission electron microscopy operating at low accelerating voltages is able to analyze, simultaneously and with single atom resolution and sensitivity, the local atomic configuration, chemical identities, and optical response at point defect sites in monolayer graphene. Sequential fast-scan annular dark-field (ADF) imaging provides direct visualization of point defect diffusion within the graphene lattice, with all atoms clearly resolved and identified via quantitative image analysis. Summing multiple ADF frames of stationary defects produce images with minimized statistical noise and reduced distortions of atomic positions. Electron energy-loss spectrum imaging of single atoms allows the delocalization of inelastic scattering to be quantified, and full quantum mechanical calculations are able to describe the delocalization effect with good accuracy. These capabilities open new opportunities to probe the defect structure, defect dynamics, and local optical properties in 2D materials with single atom sensitivity.

  3. Single atom microscopy.

    PubMed

    Zhou, Wu; Oxley, Mark P; Lupini, Andrew R; Krivanek, Ondrej L; Pennycook, Stephen J; Idrobo, Juan-Carlos

    2012-12-01

    We show that aberration-corrected scanning transmission electron microscopy operating at low accelerating voltages is able to analyze, simultaneously and with single atom resolution and sensitivity, the local atomic configuration, chemical identities, and optical response at point defect sites in monolayer graphene. Sequential fast-scan annular dark-field (ADF) imaging provides direct visualization of point defect diffusion within the graphene lattice, with all atoms clearly resolved and identified via quantitative image analysis. Summing multiple ADF frames of stationary defects produce images with minimized statistical noise and reduced distortions of atomic positions. Electron energy-loss spectrum imaging of single atoms allows the delocalization of inelastic scattering to be quantified, and full quantum mechanical calculations are able to describe the delocalization effect with good accuracy. These capabilities open new opportunities to probe the defect structure, defect dynamics, and local optical properties in 2D materials with single atom sensitivity. PMID:23146658

  4. Radiation in Particle Simulations

    SciTech Connect

    More, R M; Graziani, F R; Glosli, J; Surh, M

    2009-06-15

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of Megabars to thousands of Gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known (section 3). The second method expands the electromagnetic field in normal modes (plane-waves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion (section 4). The third method is a hybrid MD/MC (molecular dynamics/Monte Carlo) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions (section 5). The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc.(section 6). This approach is inspired by the Virial expansion method of equilibrium statistical mechanics.

  5. Atomic homodyne detection of weak atomic transitions.

    PubMed

    Gunawardena, Mevan; Elliott, D S

    2007-01-26

    We have developed a two-color, two-pathway coherent control technique to detect and measure weak optical transitions in atoms by coherently beating the transition amplitude for the weak transition with that of a much stronger transition. We demonstrate the technique in atomic cesium, exciting the 6s(2)S(1/2) --> 8s(2)S(1/2) transition via a strong two-photon transition and a weak controllable Stark-induced transition. We discuss the enhancement in the signal-to-noise ratio for this measurement technique over that of direct detection of the weak transition rate, and project future refinements that may further improve its sensitivity and application to the measurement of other weak atomic interactions.

  6. Atomic Oxygen Effects

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K. R.

    2014-01-01

    Atomic oxygen, which is the most predominant species in low Earth orbit, is highly reactive and can break chemical bonds on the surface of a wide variety of materials leading to volatilization or surface oxidation which can result in failure of spacecraft materials and components. This presentation will give an overview of how atomic oxygen reacts with spacecraft materials, results of space exposure testing of a variety of materials, and examples of failures caused by atomic oxygen.

  7. Metal atom oxidation laser

    DOEpatents

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-10-28

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides. (auth)

  8. Metal atom oxidation laser

    DOEpatents

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-10-28

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides.

  9. Advances in atomic physics

    PubMed Central

    El-Sherbini, Tharwat M.

    2013-01-01

    In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research – an overview is provided of the milestones in the fascinating landscape of atomic physics. PMID:26425356

  10. High pressure atomization

    NASA Astrophysics Data System (ADS)

    Bracco, F. V.

    1982-03-01

    The main objective of these grants has been to study the fundamental processes which lead to the atomization of high pressure jets injected into compressed gases through single hole nozzles. Specific topics include: Dependence of Spray Angle and Other Spray Parameters on Nozzle Design and Operating Conditions; Ultra High Speed Filming of Atomizing Jets; Mechanism of Breakup of Highly Super Heated Liquid Jets; Measurements of the Spray Angle of Atomizing Jets; Mechanism of Atomization of a Liquid Jet; Scaling of Transient Laminar, Turbulent, and Spray Jets; Computations of Drop Sizes in Pulsating Sprays and of Liquid Core Length in Vaporizing Sprays; and Scaling of Impulsively Started Sprays.

  11. Improved graphite furnace atomizer

    DOEpatents

    Siemer, D.D.

    1983-05-18

    A graphite furnace atomizer for use in graphite furnace atomic absorption spectroscopy is described wherein the heating elements are affixed near the optical path and away from the point of sample deposition, so that when the sample is volatilized the spectroscopic temperature at the optical path is at least that of the volatilization temperature, whereby analyteconcomitant complex formation is advantageously reduced. The atomizer may be elongated along its axis to increase the distance between the optical path and the sample deposition point. Also, the atomizer may be elongated along the axis of the optical path, whereby its analytical sensitivity is greatly increased.

  12. Quasiclassical calculations of blackbody-radiation-induced depopulation rates and effective lifetimes of Rydberg nS, nP, and nD alkali-metal atoms with n{<=}80

    SciTech Connect

    Beterov, I. I.; Ryabtsev, I. I.; Tretyakov, D. B.; Entin, V. M.

    2009-05-15

    Rates of depopulation by blackbody radiation (BBR) and effective lifetimes of alkali-metal nS, nP, and nD Rydberg states have been calculated in a wide range of principal quantum numbers n{<=}80 at the ambient temperatures of 77, 300, and 600 K. Quasiclassical formulas were used to calculate the radial matrix elements of the dipole transitions from Rydberg states. Good agreement of our numerical results with the available theoretical and experimental data has been found. We have also obtained simple analytical formulas for estimates of effective lifetimes and BBR-induced depopulation rates, which well agree with the numerical data.

  13. Atomic Oxygen Effects on Coated Tether Materials

    NASA Technical Reports Server (NTRS)

    Gittemeier, Keith A.; Hawk, Clark W.; Finckenor, Miria M.; Watts, Ed

    2005-01-01

    The University of Alabama in Huntsville s Propulsion Research Center has teamed with NASA's Marshall Space Flight Center (MSFC) to research the effects of atomic oxygen (AO) bombardment on coated tether materials. Tethers Unlimited Inc. has provided several candidate tether materials with various coatings for (AO) exposure in MSFC's Atomic Oxygen Beam Facility. Additional samples were exposed to ultraviolet (UV) radiation at MSFC. AO erodes most organic materials, and ultraviolet radiation embrittles polymers. This test series was performed to determine the effect of AO and UV on the mechanical integrity of tether materials that were treated with AO-protective coatings, such as Photosil or metallization. Both TUI's Multi-Application Survivable Tether (MAST) Experiment and Marshall Space Flight Center's Momentum Exchange Electrodynamic Reboost (MXER) programs will benefit from this research by helping to determine tether materials and coatings that give the longest life with the lowest mass penalty.

  14. Continuum Absorption Coefficient of Atoms and Ions

    NASA Technical Reports Server (NTRS)

    Armaly, B. F.

    1979-01-01

    The rate of heat transfer to the heat shield of a Jupiter probe has been estimated to be one order of magnitude higher than any previously experienced in an outer space exploration program. More than one-third of this heat load is due to an emission of continuum radiation from atoms and ions. The existing computer code for calculating the continuum contribution to the total load utilizes a modified version of Biberman's approximate method. The continuum radiation absorption cross sections of a C - H - O - N ablation system were examined in detail. The present computer code was evaluated and updated by being compared with available exact and approximate calculations and correlations of experimental data. A detailed calculation procedure, which can be applied to other atomic species, is presented. The approximate correlations can be made to agree with the available exact and experimental data.

  15. Evanescent Wave Atomic Mirror

    NASA Astrophysics Data System (ADS)

    Ghezali, S.; Taleb, A.

    2008-09-01

    A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely

  16. Atomic Oxygen Fluence Monitor

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.

    2011-01-01

    This innovation enables a means for actively measuring atomic oxygen fluence (accumulated atoms of atomic oxygen per area) that has impinged upon spacecraft surfaces. Telemetered data from the device provides spacecraft designers, researchers, and mission managers with real-time measurement of atomic oxygen fluence, which is useful for prediction of the durability of spacecraft materials and components. The innovation is a compact fluence measuring device that allows in-space measurement and transmittance of measured atomic oxygen fluence as a function of time based on atomic oxygen erosion yields (the erosion yield of a material is the volume of material that is oxidized per incident oxygen atom) of materials that have been measured in low Earth orbit. It has a linear electrical response to atomic oxygen fluence, and is capable of measuring high atomic oxygen fluences (up to >10(exp 22) atoms/sq cm), which are representative of multi-year low-Earth orbital missions (such as the International Space Station). The durability or remaining structural lifetime of solar arrays that consist of polymer blankets on which the solar cells are attached can be predicted if one knows the atomic oxygen fluence that the solar array blanket has been exposed to. In addition, numerous organizations that launch space experiments into low-Earth orbit want to know the accumulated atomic oxygen fluence that their materials or components have been exposed to. The device is based on the erosion yield of pyrolytic graphite. It uses two 12deg inclined wedges of graphite that are over a grit-blasted fused silica window covering a photodiode. As the wedges erode, a greater area of solar illumination reaches the photodiode. A reference photodiode is also used that receives unobstructed solar illumination and is oriented in the same direction as the pyrolytic graphite covered photodiode. The short-circuit current from the photodiodes is measured and either sent to an onboard data logger, or

  17. Atomic Data Applications for Supernova Modeling

    NASA Astrophysics Data System (ADS)

    Fontes, Christopher J.

    2013-06-01

    The modeling of supernovae (SNe) incorporates a variety of disciplines, including hydrodynamics, radiation transport, nuclear physics and atomic physics. These efforts require numerical simulation of the final stages of a star's life, the supernova explosion phase, and the radiation that is subsequently emitted by the supernova remnant, which can occur over a time span of tens of thousands of years. While there are several different types of SNe, they all emit radiation in some form. The measurement and interpretation of these spectra provide important information about the structure of the exploding star and the supernova engine. In this talk, the role of atomic data is highlighted as iit pertains to the modeling of supernova spectra. Recent applications [1,2] involve the Los Alamos OPLIB opacity database, which has been used to provide atomic opacities for modeling supernova plasmas under local thermodynamic equilibrium (LTE) conditions. Ongoing work includes the application of atomic data generated by the Los Alamos suite of atomic physics codes under more complicated, non-LTE conditions [3]. As a specific, recent example, a portion of the x-ray spectrum produced by Tycho's supernova remnant (SN 1572) will be discussed [4]. [1] C.L. Fryer et al, Astrophys. J. 707, 193 (2009). [2] C.L. Fryer et al, Astrophys. J. 725, 296 (2009). [3] C.J. Fontes et al, Conference Proceedings for ICPEAC XXVII, J. of Phys: Conf. Series 388, 012022 (2012). [4] K.A. Eriksen et al, Presentation at the 2012 AAS Meeting (Austin, TX). (This work was performed under the auspices of the U.S. Department of Energy by Los Alamos National Laboratory under Contract No. DE-AC52-06NA25396.)

  18. Exit channels of autoionization resonances in atoms

    SciTech Connect

    Krause, M.O.

    1985-01-01

    In many-electron atoms with open shells strong autoionization resonances occur when an electron from an inner, weakly bound subshell is excited. Usually, the resonance state lies above several ionization thresholds and, hence, will decay into more than one exit or continuum channel. Several cases are discussed in which the resonance state is induced by synchrotron radiation, and the exit channels are differentiated and characterized by the analysis of the ejected electrons.

  19. Atomic images by electron-wave holography.

    PubMed

    Bartell, L S; Ritz, C L

    1974-09-27

    Direct views of electron clouds in atoms h-ave been observed visually and photographed by means of a two-stage holographic miscroscope based on Gabor's principle of image reconstruction. Holograms are produced with 40-kilo-volt electron radiation and decoded with an optical laser. The obviation of an objective lens makes feasible a numerical aperture of 0.37 and a resolving power exceeding 0.1 angstrom.

  20. Space Radiation

    NASA Technical Reports Server (NTRS)

    Wu, Honglu

    2006-01-01

    Astronauts receive the highest occupational radiation exposure. Effective protections are needed to ensure the safety of astronauts on long duration space missions. Increased cancer morbidity or mortality risk in astronauts may be caused by occupational radiation exposure. Acute and late radiation damage to the central nervous system (CNS) may lead to changes in motor function and behavior, or neurological disorders. Radiation exposure may result in degenerative tissue diseases (non-cancer or non-CNS) such as cardiac, circulatory, or digestive diseases, as well as cataracts. Acute radiation syndromes may occur due to occupational radiation exposure.

  1. Atomic Spectroscopy for Soft-X Lasers

    NASA Astrophysics Data System (ADS)

    Pedrotti, Kenneth Donald

    The realization of lasers in the extreme ultraviolet (XUV) is hampered by a lack of knowledge concerning the location and properties of useful atomic levels. This dissertation presents the results of experimental investigations of core-excited levels in alkali-metal atoms and alkaline -earth ions. A novel hollow-cathode discharge device has been developed for production of excited atoms of interest for laser construction. This device has been used to find new levels in Na I and Mg II using emission spectroscopy. A novel high-resolution laser technique called extinction spectroscopy has been demonstrated in Li by the measurement of the lifetime of an autoionizing level. A tunable coherent radiation source at 110 nm was also developed and used to make high-resolution absorption measurements on Cs transitions considered for use in the creation of a VUV Laser.

  2. Realization of a cryogenic interface to an ultracold atomic chamber

    NASA Astrophysics Data System (ADS)

    Date, Aditya; Wang, Ke; Shaffer, Airlia; Patil, Yogesh Sharad; Schwab, Keith; Vengalattore, Mukund

    2016-05-01

    The control and manipulation of ultracold atoms in close proximity to cryogenic material surfaces opens up novel avenues for quantum sensing with cold atoms. However, integrating cryogenics with cold atomic systems presents the dual challenges of reducing thermal radiation load while allowing optimal optical access. Here, we present the realization of a unique interface between a cryogenic system and a room-temperature ultracold atomic chamber which allows for the optical trapping of cold atoms within microns of a sub-10 K cryogenic surface. Our interface serves as a platform for a cold-atoms based precision magnetic microscope for probing exotic condensed matter systems such as correlated electronic materials, as well as a platform for the realization of hybrid quantum systems. This work is supported by the DARPA QuASAR program through a grant from the ARO.

  3. Quantum-mechanical transport equation for atomic systems.

    NASA Technical Reports Server (NTRS)

    Berman, P. R.

    1972-01-01

    A quantum-mechanical transport equation (QMTE) is derived which should be applicable to a wide range of problems involving the interaction of radiation with atoms or molecules which are also subject to collisions with perturber atoms. The equation follows the time evolution of the macroscopic atomic density matrix elements of atoms located at classical position R and moving with classical velocity v. It is quantum mechanical in the sense that all collision kernels or rates which appear have been obtained from a quantum-mechanical theory and, as such, properly take into account the energy-level variations and velocity changes of the active (emitting or absorbing) atom produced in collisions with perturber atoms. The present formulation is better suited to problems involving high-intensity external fields, such as those encountered in laser physics.

  4. Modified Embedded Atom Method

    2012-08-01

    Interatomic force and energy calculation subroutine to be used with the molecular dynamics simulation code LAMMPS (Ref a.). The code evaluated the total energy and atomic forces (energy gradient) according to a cubic spline-based variant (Ref b.) of the Modified Embedded Atom Method (MEAM) with a additional Stillinger-Weber (SW) contribution.

  5. Atomic and Molecular Physics

    NASA Technical Reports Server (NTRS)

    Bhatia, Anand K.

    2005-01-01

    A symposium on atomic and molecular physics was held on November 18, 2005 at Goddard Space Flight Center. There were a number of talks through the day on various topics such as threshold law of ionization, scattering of electrons from atoms and molecules, muonic physics, positron physics, Rydberg states etc. The conference was attended by a number of physicists from all over the world.

  6. Greek Atomic Theory.

    ERIC Educational Resources Information Center

    Roller, Duane H. D.

    1981-01-01

    Focusing on history of physics, which began about 600 B.C. with the Ionian Greeks and reaching full development within three centuries, suggests that the creation of the concept of the atom is understandable within the context of Greek physical theory; so is the rejection of the atomic theory by the Greek physicists. (Author/SK)

  7. Atomic Power Safety.

    ERIC Educational Resources Information Center

    Hogerton, John F.

    This publication is one of a series of information booklets for the general public published by The United States Atomic Energy Commission. Among the topics discussed are: What is Atomic Power?; What Does Safety Depend On?; Control of Radioactive Material During Operation; Accident Prevention; Containment in the Event of an Accident; Licensing and…

  8. When Atoms Want

    ERIC Educational Resources Information Center

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  9. Atomic Scale Plasmonic Switch.

    PubMed

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2016-01-13

    The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.

  10. Spontaneous excitation of a circularly accelerated atom coupled with vacuum Dirac field fluctuations

    SciTech Connect

    Chen, Jing; Hu, Jiawei; Yu, Hongwei

    2015-02-15

    We study the spontaneous excitation of a circularly accelerated atom coupled with vacuum Dirac field fluctuations by separately calculating the contribution to the excitation rate of vacuum fluctuations and a cross term which involves both vacuum fluctuations and radiation reaction, and demonstrate that although the spontaneous excitation for the atom in its ground state would occur in vacuum, such atoms in circular motion do not perceive a pure thermal radiation as their counterparts in linear acceleration do since the transition rates of the atom do not contain the Planckian factor characterizing a thermal bath. We also find that the contribution of the cross term that plays the same role as that of radiation reaction in the scalar and electromagnetic fields cases differs for atoms in circular motion from those in linear acceleration. This suggests that the conclusion drawn for atoms coupled with the scalar and electromagnetic fields that the contribution of radiation reaction to the mean rate of change of atomic energy does not vary as the trajectory of the atom changes from linear acceleration to circular motion is not a general trait that applies to the Dirac field where the role of radiation reaction is played by the cross term. - Highlights: • Spontaneous excitation of a circularly accelerated atom is studied. • The atom interacts with the Dirac field through nonlinear coupling. • A cross term involving vacuum fluctuations and radiation reaction contributes. • The atom in circular motion does not perceive pure thermal radiation. • The contribution of the cross term changes as the atomic trajectory varies.

  11. An Investigation of Trajectories of Atoms in Mercury's Exosphere

    NASA Astrophysics Data System (ADS)

    Bradley, Eric Todd

    2016-10-01

    Mercury's neutral exosphere consists of atoms or molecules ejected from the surface that are on individual trajectories that may re-impact the surface if there is insufficient energy to escape the gravity of the planet. This is an investigation of how the radiation pressure, orbital acceleration of the planet, and planetary rotation combine together to produce complicated trajectories. Because of Mercury's non-zero eccentricity the planet is not in uniform circular motion, which leads to radial and tangential accelerations that vary throughout the Mercury year. Besides radiation pressure the trajectory of an exospheric atom is affected by the planet accelerating during the time of flight of the atom that 1) causes the atom's position with respect to the ejection point to vary in a manner that is different than if the planet were not accelerating and 2) causes the planet-atom distance to vary in a manner that is different than for a typical ballistic trajectory resulting in variation of the gravitational force that the planet exerts on the atom. These effects are small but persistent and affect where the atom re-impacts the surface, which may lead to asymmetrical distributions of atoms in the surface regolith and exosphere.Preliminary results from simulations of ejected atoms that include 1) radiation pressure that varies with the atom's velocity due to Doppler shifting, 2) radial and tangential accelerations of the planet, and 3) the variation of the planet's gravity on the atom with distance above the planet show that atoms ejected at low energies normal to the surface from the subsolar point re-impact on the dusk side hemisphere of the planet. However atoms ejected at high energies normal to the surface from the subsolar point re-impact on the dawn side hemisphere of the planet. A fraction of atoms ejected normal to the surface from the dawn terminator within an energy range that results in the atom re-impacting and sticking to the night side surface behind the

  12. Moving Single Atoms

    NASA Astrophysics Data System (ADS)

    Stuart, Dustin

    2016-05-01

    Single neutral atoms are promising candidates for qubits, the fundamental unit of quantum information. We have built a set of optical tweezers for trapping and moving single Rubidium atoms. The tweezers are based on a far off-resonant dipole trapping laser focussed to a 1 μm spot with a single aspheric lens. We use a digital micromirror device (DMD) to generate dynamic holograms of the desired arrangement of traps. The DMD has a frame rate of 20 kHz which, when combined with fast algorithms, allows for rapid reconfiguration of the traps. We demonstrate trapping of up to 20 atoms in arbitrary arrangements, and the transport of a single-atom over a distance of 14 μm with continuous laser cooling, and 5 μm without. In the meantime, we are developing high-finesse fibre-tip cavities, which we plan to use to couple pairs of single atoms to form a quantum network.

  13. Atomic Oxygen Textured Polymers

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Hunt, Jason D.; Drobotij, Erin; Cales, Michael R.; Cantrell, Gidget

    1995-01-01

    Atomic oxygen can be used to microscopically alter the surface morphology of polymeric materials in space or in ground laboratory facilities. For polymeric materials whose sole oxidation products are volatile species, directed atomic oxygen reactions produce surfaces of microscopic cones. However, isotropic atomic oxygen exposure results in polymer surfaces covered with lower aspect ratio sharp-edged craters. Isotropic atomic oxygen plasma exposure of polymers typically causes a significant decrease in water contact angle as well as altered coefficient of static friction. Such surface alterations may be of benefit for industrial and biomedical applications. The results of atomic oxygen plasma exposure of thirty-three (33) different polymers are presented, including typical morphology changes, effects on water contact angle, and coefficient of static friction.

  14. Coaxial airblast atomizers

    NASA Technical Reports Server (NTRS)

    Hardalupas, Y.; Whitelaw, J. H.

    1993-01-01

    An experimental investigation was performed to quantify the characteristics of the sprays of coaxial injectors with particular emphasis on those aspects relevant to the performance of rocket engines. Measurements for coaxial air blast atomizers were obtained using air to represent the gaseous stream and water to represent the liquid stream. A wide range of flow conditions were examined for sprays with and without swirl for gaseous streams. The parameters varied include Weber number, gas flow rate, liquid flow rate, swirl, and nozzle geometry. Measurements were made with a phase Doppler velocimeter. Major conclusions of the study focused upon droplet size as a function of Weber number, effect of gas flow rate on atomization and spray spread, effect of nozzle geometry on atomization and spread, effect of swirl on atomization, spread, jet recirculation and breakup, and secondary atomization.

  15. An intermetallic forming steel under radiation for nuclear applications

    NASA Astrophysics Data System (ADS)

    Hofer, C.; Stergar, E.; Maloy, S. A.; Wang, Y. Q.; Hosemann, P.

    2015-03-01

    In this work we investigated the formation and stability of intermetallics formed in a maraging steel PH 13-8 Mo under proton radiation up to 2 dpa utilizing nanoindentation, microcompression testing and atom probe tomography. A comprehensive discussion analyzing the findings utilizing rate theory is introduced, comparing the aging process to radiation induced diffusion. New findings of radiation induced segregation of undersize solute atoms (Si) towards the precipitates are considered.

  16. Atomic bomb survivors and the sigmoidal response model

    SciTech Connect

    Kondo, S.

    1994-12-31

    Epidemiological data on health effects of low-level radiation based on 40-yr followup studies of 75000 atomic bomb survivors and 35000 control people show that there were no measurable risks from low-level radiation in regard to noncancer diseases, genetic, teratogenic, and carcinogenic effects. However, seemingly sigmoidal responses of bomb radiation-induced cancers, which must have been caused by tumorigenic mutations contradict experimental results that mutations linearly increase with increase in radiation dose. An explanation is proposed for this superficial contradiction.

  17. Radiation Exposure

    MedlinePlus

    Radiation is energy that travels in the form of waves or high-speed particles. It occurs naturally in sunlight. Man-made radiation is used in X-rays, nuclear weapons, nuclear power plants and cancer treatment. If you are exposed to small amounts of radiation over a ...

  18. [Basis of radiation protection].

    PubMed

    Roth, J; Schweizer, P; Gückel, C

    1996-06-29

    After an introduction, three selected contributions to the 10th Course on Radiation Protection held at the University Hospital of Basel are presented. The principles of radiation protection and new Swiss legislation are discussed as the basis for radiological protection. Ways are proposed of reducing radiation exposure while optimizing the X-ray picture with a minimum dose to patient and personnel. Radiation effects from low doses. From the beginning, life on this planet has been exposed to ionizing radiation from natural sources. For about one century additional irradiation has reached us from man-made sources as well. In Switzerland the overall annual radiation exposure from ambient and man-made sources amounts to about 4 mSv. The terrestrial and cosmic radiation and natural radionuclids in the body cause about 1.17 mSv (29%). As much as 1.6 mSv (40%) results from exposure to radon and its progenies, primarily inside homes. Medical applications contribute approximately 1 mSv (26%) to the annual radiation exposure and releases from atomic weapons, nuclear facilities and miscellaneous industrial operations yield less than 0.12 mSv (< 5%) to the annual dose. Observations of detrimental radiation effects from intermediate to high doses are challenged by observations of biopositive adaptive responses and hormesis following low dose exposure. The important question, whether cellular adaptive response or hormesis could cause beneficial effects to the human organism that would outweigh the detrimental effects attributed to low radiation doses, remains to be resolved. Whether radiation exerts a detrimental, inhibitory, modifying or even beneficial effect is likely to result from identical molecular lesions but to depend upon their quantity, localization and time scale of initiation, as well as the specific responsiveness of the cellular systems involved. For matters of radiation protection the bionegative radiation effects are classified as deterministic effects or

  19. Directed spontaneous emission from an extended ensemble of N atoms: timing is everything.

    PubMed

    Scully, Marlan O; Fry, Edward S; Ooi, C H Raymond; Wódkiewicz, Krzysztof

    2006-01-13

    A collection of static atoms is fixed in a crystal at a low temperature and prepared by a pulse of incident radiation of wave vector . The atoms are well described by an entangled Dicke-like state, in which each atom carries a characteristic phase factor exp(ik0.r(j)), where is the atomic position in the crystal. It is shown that a single photon absorbed by the N atoms will be followed by spontaneous emission in the same direction. Furthermore, phase matched emission is found when one photon is absorbed by N atoms followed by two-photon down-conversion.

  20. Producing and Detecting Correlated Atoms

    SciTech Connect

    Westbrook, C. I.; Schellekens, M.; Perrin, A.; Krachmalnicoff, V.; Viana Gomes, J.; Trebbia, J.-B.; Esteve, J.; Chang, H.; Bouchoule, I.; Boiron, D.; Aspect, A.; Jeltes, T.; McNamara, J.; Hogervorst, W.; Vassen, W.

    2006-11-07

    We discuss experiments to produce and detect atom correlations in a degenerate or nearly degenerate gas of neutral atoms. First we treat the atomic analog of the celebrated Hanbury Brown Twiss experiment, in which atom correlations result simply from interference effects without any atom interactions. We have performed this experiment for both bosons and fermions. Next we show how atom interactions produce correlated atoms using the atomic analog of spontaneous four-wave mixing. Finally, we briefly mention experiments on a one dimensional gas on an atom chip in which correlation effects due to both interference and interactions have been observed.

  1. Aiming Optimum Space Radiation Protection using Regolith.

    NASA Astrophysics Data System (ADS)

    Masuda, Daisuke; Nagamatsu, Aiko; Indo, Hiroko; Iwashita, Yoichiro; Suzuki, Hiromi; Shimazu, Toru; Yano, Sachiko; Tanigaki, Fumiaki; Ishioka, Noriaki; Mukai, Chiaki; Majima, Hideyuki J.

    Radiation protection of space radiation is very important factor in manned space activity on the moon. At the construction of lunar base, low cost radiation shielding would be achieved using regolith that exists on the surface of the moon. We studied radiation shielding ability of regolith as answer the question, how much of depth would be necessary to achieve minimum radiation protection. We estimated the shielding ability of regolith against each atomic number of space radiation particles. Using stopping power data of ICRU REPORT49 and 73, we simulated the approximate expression (function of the energy of the atomic nucleus as x and the atomic number as Z) of the stopping power for the space proton particle (nucleus of H) against silicon dioxide (SiO2), aluminum oxide (Al2O3), and iron (Fe), which are the main components of regolith. Based on the expression, we applied the manipulation to the other particles of space radiation to up to argon particle (Ar). These simulated expressions complied well the data of ICRU REPORT49 and 73 except alpha particle (nucleus of He). The simulation values of stop-ping power of ten elements from potassium to nickel those we had no data in ICRU REPORT were further simulated. Using the obtained expressions, the relationship between the radiation absorbed dose and depth of a silicon dioxide was obtained. The space radiation relative dose with every depth in the moon could be estimated by this study.

  2. Photonic, Electronic and Atomic Collisions

    NASA Astrophysics Data System (ADS)

    Fainstein, Pablo D.; Lima, Marco Aurelio P.; Miraglia, Jorge E.; Montenegro, Eduardo C.; Rivarola, Roberto D.

    2006-11-01

    Plenary. Electron collisions - past, present and future / J. W. McConkey. Collisions of slow highly charged ions with surfaces / J. Burgdörfer ... [et al.]. Atomic collisions studied with "reaction-microscopes" / R. Moshammer ... [et al.]. Rydberg atoms: a microscale laboratory for studying electron-molecule tnteractions / F. B. Dunning -- Collisions involvintg photons. Quantum control of photochemical reaction dynamics and molecular functions / M. Yamaki ... [et al.]. Manipulating and viewing Rydberg wavepackets / R. R. Jones. Angle-resolved photoelectrons as a probe of strong-field interactions / M. Vrakking. Ultracold Rydberg atoms in a structured environment / I. C. H. Liu and J. M. Rost. Synchrotron-radiation-based recoil ion momentum spectroscopy of laser cooled and trapped cesium atoms / L. H. Coutinho. Reconstruction of attosecond pulse trains / Y. Mairesse ... [et al.]. Selective excitation of metastable atomic states by Femto- and attosecond laser pulses / A. D. Kondorskiy. Accurate calculations of triple differential cross sections for double photoionization of the hygrogen molecule / W. Vanroose ... [et al.]. Double and triple photoionization of Li and Be / J. Colgan, M. S. Pindzola and F. Robicheaux. Few/many body dynamics in strong laser fields / J. Zanghellini and T. Brabec. Rescattering-induced effects in electron-atom scattering in the presence of a circularly polarized laser field / A. V. Flegel ... [et al.]. Multidimensional photoelectron spectroscopy / P. Lablanquie ... [et al.]. Few photon and strongly driven transitions in the XUV and beyond / P. Lambropoulos, L. A. A. Nikolopoulos and S. I. Themelis. Ionization dynamics of atomic clusters in intense laser pulses / U. Saalmann and J. M. Rost. On the second order autocorrelation of an XUV attosecond pulse train / E. P. Benis ... [et al.]. Evidence for rescattering in molecular dissociation / I. D. Williams ... [et al.]. Photoionizing ions using synchrotron radiation / R. Phaneuf. Photo double

  3. Coherent and incoherent dipole-dipole interactions between atoms

    NASA Astrophysics Data System (ADS)

    Robicheaux, Francis

    2016-05-01

    Results will be presented on the collective interaction between atoms due to the electric dipole-dipole coupling between states of different parity on two different atoms. A canonical example of this effect is when the electronic state of one atom has S-character and the state of another atom has P-character. The energy difference between the two states plays an important role in the interaction since the change in energy determines the wave number of a photon that would cause a transition between the states. If the atoms are much closer than the wave length of this photon, then the dipole-dipole interaction is in the near field and has a 1 /r3 dependence on atomic separation. If the atoms are farther apart than the wave length, then the interaction is in the far field and has a 1 / r dependence. When many atoms interact, collective effects can dominate the system with the character of the collective effect depending on whether the atomic separation leads to near field or far field coupling. As an example of the case where the atoms are in the far field, the line broadening of transitions and strong deviations from the Beer-Lambert law in a diffuse gas will be presented. As an example of near field collective behavior, the radiative properties of a Rydberg gas will be presented. Based upon work supported by the National Science Foundation under Grant No. 1404419-PHY in collaboration with R.T. Sutherland.

  4. Early atomic models - from mechanical to quantum (1904-1913)

    NASA Astrophysics Data System (ADS)

    Baily, C.

    2013-01-01

    A complete history of early atomic models would fill volumes, but a reasonably coherent tale of the path from mechanical atoms to the quantum can be told by focusing on the relevant work of three great contributors to atomic physics, in the critically important years between 1904 and 1913: J.J. Thomson, Ernest Rutherford and Niels Bohr. We first examine the origins of Thomson's mechanical atomic models, from his ethereal vortex atoms in the early 1880's, to the myriad "corpuscular" atoms he proposed following the discovery of the electron in 1897. Beyond qualitative predictions for the periodicity of the elements, the application of Thomson's atoms to problems in scattering and absorption led to quantitative predictions that were confirmed by experiments with high-velocity electrons traversing thin sheets of metal. Still, the much more massive and energetic α-particles being studied by Rutherford were better suited for exploring the interior of the atom, and careful measurements on the angular dependence of their scattering eventually allowed him to infer the existence of an atomic nucleus. Niels Bohr was particularly troubled by the radiative instability inherent to any mechanical atom, and succeeded in 1913 where others had failed in the prediction of emission spectra, by making two bold hypotheses that were in contradiction to the laws of classical physics, but necessary in order to account for experimental facts.

  5. Radiation Proctopathy

    PubMed Central

    Grodsky, Marc B.; Sidani, Shafik M.

    2015-01-01

    Radiation therapy is a widely utilized treatment modality for pelvic malignancies, including prostate cancer, rectal cancer, and cervical cancer. Given its fixed position in the pelvis, the rectum is at a high risk for injury secondary to ionizing radiation. Despite advances made in radiation science, up to 75% of the patients will suffer from acute radiation proctitis and up to 20% may experience chronic symptoms. Symptoms can be variable and include diarrhea, bleeding, incontinence, and fistulization. A multitude of treatment options exist. This article summarizes the latest knowledge relating to radiation proctopathy focusing on the vast array of treatment options. PMID:26034407

  6. Radiation proctopathy.

    PubMed

    Grodsky, Marc B; Sidani, Shafik M

    2015-06-01

    Radiation therapy is a widely utilized treatment modality for pelvic malignancies, including prostate cancer, rectal cancer, and cervical cancer. Given its fixed position in the pelvis, the rectum is at a high risk for injury secondary to ionizing radiation. Despite advances made in radiation science, up to 75% of the patients will suffer from acute radiation proctitis and up to 20% may experience chronic symptoms. Symptoms can be variable and include diarrhea, bleeding, incontinence, and fistulization. A multitude of treatment options exist. This article summarizes the latest knowledge relating to radiation proctopathy focusing on the vast array of treatment options. PMID:26034407

  7. Precisely detecting atomic position of atomic intensity images.

    PubMed

    Wang, Zhijun; Guo, Yaolin; Tang, Sai; Li, Junjie; Wang, Jincheng; Zhou, Yaohe

    2015-03-01

    We proposed a quantitative method to detect atomic position in atomic intensity images from experiments such as high-resolution transmission electron microscopy, atomic force microscopy, and simulation such as phase field crystal modeling. The evaluation of detection accuracy proves the excellent performance of the method. This method provides a chance to precisely determine atomic interactions based on the detected atomic positions from the atomic intensity image, and hence to investigate the related physical, chemical and electrical properties.

  8. Atomic mass evaluation

    SciTech Connect

    Wang, M.; Audi, G.; Kondev, F. G.; Xu, X.; Pfeiffer, B.

    2012-11-12

    The atomic masses are important input parameters for nuclear astrophysics calculations. The Atomic Mass Evaluation (AME) is the most reliable source for comprehensive information related to atomic masses. The latest AME was published in 2003. A new version, which will include the impact of a wealth of new, high-precision experimental data, will be published in December 2012. In this paper we will give the current status of AME2012. The mass surface has been changed significantly compared to AME2003, and the impact on astrophysics calculations is discussed.

  9. Atomic and molecular supernovae

    NASA Technical Reports Server (NTRS)

    Liu, Weihong

    1997-01-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  10. Atom trap trace analysis

    SciTech Connect

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  11. Radiation and Its Health Effects. AIO Red Paper #19.

    ERIC Educational Resources Information Center

    Duda, Terrie

    Radiation has been a serious concern to individuals for over 100 years. A process by which an atomic nucleus emits particles to reach a more stable energy state, radiation harms living cells (usually by inhalation and absorption into the lungs) by causing abnormal cell function and structure. Man is constantly exposed to background radiation, both…

  12. Reconstruction of individual radiation doses for a case-control study of thyroid cancer in French Polynesia.

    PubMed

    Drozdovitch, Vladimir; Bouville, André; Doyon, Françoise; Brindel, Pauline; Cardis, Elisabeth; de Vathaire, Florent

    2008-05-01

    Forty-one atmospheric nuclear weapons tests (plus five safety tests) were conducted in French Polynesia between 1966 and 1974. To evaluate the potential role of atmospheric nuclear weapons testing on a high incidence of thyroid cancer observed since 1985 in French Polynesia, a population-based case-control study was performed. The study included 602 subjects, either cases or controls, all aged less than 40 y at the end of nuclear weapons testing in 1974. Radiation doses to the thyroids of the study subjects were assessed based on the available historical results of radiation measurements. These were mainly found in the annual reports on the radiological situation in French Polynesia that had been sent to the UNSCEAR Secretariat. For each atmospheric nuclear weapons test that contributed substantially to the local deposition of radionuclides, the radiation dose to the thyroid from I intake was estimated. In addition, thyroid doses from the intake of short-lived radioiodines (132I, 133I, 135I) and 132Te, external exposure from gamma-emitted radionuclides deposited on the ground, and ingestion of long-lived Cs were reconstructed. The mean thyroid dose among the study subjects was found to be around 3 mGy while the highest dose was estimated to be around 40 mGy. Doses from short-lived iodine and tellurium isotopes ranged up to 10 mGy. Thyroid doses from external exposure ranged up to 3 mGy, while those from internal exposure due to cesium ingestion did not exceed 1 mGy. The dose estimates that have been obtained are based on a rather limited number of radiation measurements performed on a limited number of islands and are highly uncertain. A thorough compilation of the results of all radiation monitoring that was performed in French Polynesia in 1966-1974 would be likely to greatly improve the reliability and the precision of the dose estimates.

  13. Interactions of Rydberg atoms in MOTs

    NASA Astrophysics Data System (ADS)

    Feldbaum, David M.

    We have studied the development of gases of ultra-cold Rydberg atoms in Magneto Optic Traps, and discovered that such gases exhibit a range of density-dependent phenomena. In particular, we have found that at the densities of ˜ 107 cm-3 the Rydberg atoms spontaneously evolve into long-lived high angular momentum states. These states slowly decay due to microwave background radiation over tens of milliseconds. We have numerically simulated the effects leading to such behavior, and investigated numerically the l- and n-mixing collisions of Rydberg atoms with electrons in the range of 10 meV. These calculations show that the l- and n-mixing cross-sections follow the n5 scaling law, expected from simple Stark map considerations, but also depend on the velocities of the colliding electrons, reflecting the adiabaticity of the atom-electron interactions. We have developed a novel technique of measuring the electric fields inside plasmas by using Rydberg excitation spectroscopy of embedded atoms, based on the disappearance of regions of zero oscillator strength in the presence of such fields. We have applied this technique to study the evolution of ultra-cold non-neutral plasmas excited from the MOT, and have found that it expands over 1 mus. We have simulated such an expansion by considering only Coulomb repulsion between the constituent ions, and have found that such a model is consistent with the experimental observations.

  14. A report from the 2013 international symposium: the evaluation of the effects of low-dose radiation exposure in the life span study of atomic bomb survivors and other similar studies.

    PubMed

    Grant, E J; Ozasa, K; Ban, N; de González, A Berrington; Cologne, J; Cullings, H M; Doi, K; Furukawa, K; Imaoka, T; Kodama, K; Nakamura, N; Niwa, O; Preston, D L; Rajaraman, P; Sadakane, A; Saigusa, S; Sakata, R; Sobue, T; Sugiyama, H; Ullrich, R; Wakeford, R; Yasumura, S; Milder, C M; Shore, R E

    2015-05-01

    The RERF International Low-Dose Symposium was held on 5-6 December 2013 at the RERF campus in Hiroshima, Japan, to discuss the issues facing the Life Span Study (LSS) and other low-dose studies. Topics included the current status of low-dose risk detection, strategies for low-dose epidemiological and statistical research, methods to improve communication between epidemiologists and biologists, and the current status of radiological studies and tools. Key points made by the participants included the necessity of pooling materials over multiple studies to gain greater insight where data from single studies are insufficient; generating models that reflect epidemiological, statistical, and biological principles simultaneously; understanding confounders and effect modifiers in the current data; and taking into consideration less studied factors such as the impact of dose rate. It is the hope of all participants that this symposium be used as a trigger for further studies, especially those using pooled data, in order to reach a greater understanding of the health effects of low-dose radiation.

  15. A report from the 2013 international symposium: the evaluation of the effects of low-dose radiation exposure in the life span study of atomic bomb survivors and other similar studies.

    PubMed

    Grant, E J; Ozasa, K; Ban, N; de González, A Berrington; Cologne, J; Cullings, H M; Doi, K; Furukawa, K; Imaoka, T; Kodama, K; Nakamura, N; Niwa, O; Preston, D L; Rajaraman, P; Sadakane, A; Saigusa, S; Sakata, R; Sobue, T; Sugiyama, H; Ullrich, R; Wakeford, R; Yasumura, S; Milder, C M; Shore, R E

    2015-05-01

    The RERF International Low-Dose Symposium was held on 5-6 December 2013 at the RERF campus in Hiroshima, Japan, to discuss the issues facing the Life Span Study (LSS) and other low-dose studies. Topics included the current status of low-dose risk detection, strategies for low-dose epidemiological and statistical research, methods to improve communication between epidemiologists and biologists, and the current status of radiological studies and tools. Key points made by the participants included the necessity of pooling materials over multiple studies to gain greater insight where data from single studies are insufficient; generating models that reflect epidemiological, statistical, and biological principles simultaneously; understanding confounders and effect modifiers in the current data; and taking into consideration less studied factors such as the impact of dose rate. It is the hope of all participants that this symposium be used as a trigger for further studies, especially those using pooled data, in order to reach a greater understanding of the health effects of low-dose radiation. PMID:25811153

  16. Kinetics of Fast Atoms in the Terrestrial Atmosphere

    NASA Technical Reports Server (NTRS)

    Kharchenko, Vasili A.; Dalgarno, A.; Mellott, Mary (Technical Monitor)

    2002-01-01

    This report summarizes our investigations performed under NASA Grant NAG5-8058. The three-year research supported by the Geospace Sciences SR&T program (Ionospheric, Thermospheric, and Mesospheric Physics) has been designed to investigate fluxes of energetic oxygen and nitrogen atoms in the terrestrial thermosphere. Fast atoms are produced due to absorption of the solar radiation and due to coupling between the ionosphere and the neutral thermospheric gas. We have investigated the impact of hot oxygen and nitrogen atoms on the thermal balance, chemistry and radiation properties of the terrestrial thermosphere. Our calculations have been focused on the accurate quantitative description of the thermalization of O and N energetic atoms in collisions with atom and molecules of the ambient neutral gas. Upward fluxes of oxygen and nitrogen atoms, the rate of atmospheric heating by hot oxygen atoms, and the energy input into translational and rotational-vibrational degrees of atmospheric molecules have been evaluated. Altitude profiles of hot oxygen and nitrogen atoms have been analyzed and compared with available observational data. Energetic oxygen atoms in the terrestrial atmosphere have been investigated for decades, but insufficient information on the kinetics of fast atmospheric atoms has been a main obstacle for the interpretation of observational data and modeling of the hot geocorona. The recent development of accurate computational methods of the collisional kinetics is seen as an important step in the quantitative description of hot atoms in the thermosphere. Modeling of relaxation processes in the terrestrial atmosphere has incorporated data of recent observations, and theoretical predictions have been tested by new laboratory measurements.

  17. The CHIANTI atomic database

    NASA Astrophysics Data System (ADS)

    Young, P. R.; Dere, K. P.; Landi, E.; Del Zanna, G.; Mason, H. E.

    2016-04-01

    The freely available CHIANTI atomic database was first released in 1996 and has had a huge impact on the analysis and modeling of emissions from astrophysical plasmas. It contains data and software for modeling optically thin atom and positive ion emission from low density (≲1013 cm-3) plasmas from x-ray to infrared wavelengths. A key feature is that the data are assessed and regularly updated, with version 8 released in 2015. Atomic data for modeling the emissivities of 246 ions and neutrals are contained in CHIANTI, together with data for deriving the ionization fractions of all elements up to zinc. The different types of atomic data are summarized here and their formats discussed. Statistics on the impact of CHIANTI to the astrophysical community are given and examples of the diverse range of applications are presented.

  18. The Atomic Dating Game.

    ERIC Educational Resources Information Center

    Cummo, Evelyn; Matthews, Catherine E.

    2002-01-01

    Presents an activity designed to provide students with opportunities to practice drawing atomic models and discover the logical pairings of whole families on the periodic table. Follows the format of a television game show. (DDR)

  19. Atomic hydrogen rocket engine

    NASA Technical Reports Server (NTRS)

    Etters, R. D.; Flurchick, K.

    1981-01-01

    A rocket using atomic hydrogen propellant is discussed. An essential feature of the proposed engine is that the atomic hydrogen fuel is used as it is produced, thus eliminating the necessity of storage. The atomic hydrogen flows into a combustion chamber and recombines, producing high velocity molecular hydrogen which flows out an exhaust port. Standard thermodynamics, kinetic theory and wall recombination cross-sections are used to predict a thrust of approximately 1.4 N for a RF hydrogen flow rate of 4 x 10 to the 22nd/sec. Specific impulses are nominally from 1000 to 2000 sec. It is predicted that thrusts on the order of one Newton and specific impulses of up to 2200 sec are attainable with nominal RF discharge fluxes on the order of 10 to the 22nd atoms/sec; further refinements will probably not alter these predictions by more than a factor of two.

  20. Atomic branching in molecules

    NASA Astrophysics Data System (ADS)

    Estrada, Ernesto; Rodríguez-Velázquez, Juan A.; Randić, Milan

    A graph theoretic measure of extended atomic branching is defined that accounts for the effects of all atoms in the molecule, giving higher weight to the nearest neighbors. It is based on the counting of all substructures in which an atom takes part in a molecule. We prove a theorem that permits the exact calculation of this measure based on the eigenvalues and eigenvectors of the adjacency matrix of the graph representing a molecule. The definition of this measure within the context of the Hückel molecular orbital (HMO) and its calculation for benzenoid hydrocarbons are also studied. We show that the extended atomic branching can be defined using any real symmetric matrix, as well as any Hermitian (self-adjoint) matrix, which permits its calculation in topological, geometrical, and quantum chemical contexts.