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Sample records for level ionising radiation

  1. European Code against Cancer 4th Edition: Ionising and non-ionising radiation and cancer.

    PubMed

    McColl, Neil; Auvinen, Anssi; Kesminiene, Ausrele; Espina, Carolina; Erdmann, Friederike; de Vries, Esther; Greinert, Rüdiger; Harrison, John; Schüz, Joachim

    2015-12-01

    Ionising radiation can transfer sufficient energy to ionise molecules, and this can lead to chemical changes, including DNA damage in cells. Key evidence for the carcinogenicity of ionising radiation comes from: follow-up studies of the survivors of the atomic bombings in Japan; other epidemiological studies of groups that have been exposed to radiation from medical, occupational or environmental sources; experimental animal studies; and studies of cellular responses to radiation. Considering exposure to environmental ionising radiation, inhalation of naturally occurring radon is the major source of radiation in the population - in doses orders of magnitude higher than those from nuclear power production or nuclear fallout. Indoor exposure to radon and its decay products is an important cause of lung cancer; radon may cause approximately one in ten lung cancers in Europe. Exposures to radon in buildings can be reduced via a three-step process of identifying those with potentially elevated radon levels, measuring radon levels, and reducing exposure by installation of remediation systems. In the 4th Edition of the European Code against Cancer it is therefore recommended to: "Find out if you are exposed to radiation from naturally high radon levels in your home. Take action to reduce high radon levels". Non-ionising types of radiation (those with insufficient energy to ionise molecules) - including extremely low-frequency electric and magnetic fields as well as radiofrequency electromagnetic fields - are not an established cause of cancer and are therefore not addressed in the recommendations to reduce cancer risk. PMID:26126928

  2. Nucleoplasmic bridges and acrocentric chromosome associations as early markers of exposure to low levels of ionising radiation in occupationally exposed hospital workers.

    PubMed

    Caradonna, Fabio

    2015-03-01

    Ionising radiation, with the contribution of telomere shortening, induces DNA double-strand breaks that result in chromosome end fusion, nucleoplasmic bridges (NPBs) and chromosome aberrations (ChAbs) as well as dicentric chromosomes. In order to investigate the chromosomal damage induced by occupational ionising radiation at low exposure levels, and to find early markers of health hazard, peripheral lymphocytes of occupationally exposed hospital workers were cytogenetically analysed. Results showed a significant difference in the frequency of ChAbs in exposed subjects relative to controls. A significant number of NPBs between nuclei of binucleated cultured lymphocytes from exposed subjects were also observed, as well as a consistent amount of acrocentric chromosomes with associations of their short arms. Excluding confounding factors, the frequencies of all these three biological endpoints differed significantly in exposed subjects from those in controls. Because the absence of telomeres and/or their short length could be a common root for both the findings, we utilised fluorescence in situ hybridisation technique with telomeric repeat as probe to demonstrate that, in exposed subjects, chromatin of short arms of involved acrocentric chromosomes did not exhibit a telomeric shortening but appeared strongly decondensed. This finding suggests that NPBs and telomeric acrocentric association should be regarded as early markers of exposure to low levels of ionising radiation and their increase should be seen as an early warning for the health of the involved workers. PMID:25381312

  3. [Thyroid cancer following exposure to ionising radiation].

    PubMed

    Schlumberger, M; Chevillard, S; Ory, K; Dupuy, C; Le Guen, B; de Vathaire, F

    2011-08-01

    Exposure to ionising radiations during childhood increases the risk of thyroid cancer. Similar risk factors have been found after external radiation exposure or internal contamination with radioactive iodine isotopes. In case of contamination with radioiodines, administration of potassium iodide can prevent thyroid irradiation. PMID:21723770

  4. Ionising radiation: are orthopaedic surgeons at risk?

    PubMed Central

    Smith, G. L.; Briggs, T. W.; Lavy, C. B.; Nordeen, H.

    1992-01-01

    Modern orthopaedic trauma practice involves increased exposure of the surgeon to ionising radiation. However, there have been no studies to investigate whether the doses received are within limits for non-classified workers. In this study, whole body, eye and extremity, namely hand, doses were measured in six orthopaedic surgeons during trauma cases requiring the use of X-rays in theatre. None of the subjects approached the recommended maximum dose levels for either the whole body, eyes or hands. This finding is reassuring. In orthopaedics, the limiting dose is that to the hands. This differs from previously studied groups, such as radiologists and cardiologists, in whom the limiting factor is the dose to the lens of the eye. Although current precautions appear to be adequate, safe practice in the future will depend on continuing vigilance and repetition of studies similar to this one as techniques and workloads change. PMID:1416705

  5. Romanian medical exposure to ionising radiation in 2012.

    PubMed

    Girjoaba, O; Cucu, A

    2015-07-01

    Medical exposure, the main source of artificial exposure, shows an increasing trend in the last years, manifested both by increasing the number of examinations with ionising radiation and by increasing the patient dose level. Annual results obtained for medical exposure to ionising radiation based on the data collected from Romanian hospitals are useful for the update of the national database and optimisation of diagnostic procedures in radiology and nuclear medicine. Medical exposure level is expressed in terms of annual collective dose and is evaluated from annual frequencies and the average effective dose per procedure for different types of radiological and nuclear medicine procedures. The Romanian hospitals reported during 2012 a number of 5,505,792 radiological examinations and 17,088 diagnostic procedures of nuclear medicine. Based on the data reported, the average effective doses and their contributions to the collective dose were evaluated. The main contributions to the collective dose of the radiological procedures are registered for CT abdomen and pelvis region, followed by thorax CT and head CT examinations. The next positions are fluoroscopic examination of the thorax and gastrointestinal disease and radiographic examination of the lumbar spine and thorax, which in spite of their low effective dose have an important contribution to the collective dose due to the large number of examinations. For nuclear medicine procedures, major contributions to collective dose are given by bone scintigraphy, followed by PET-CT and thyroid scintigraphy. PMID:25848102

  6. Occupational Exposure to Natural Sources of Ionising Radiation in Ireland

    SciTech Connect

    Organo, Catherine; Colgan, Tony; Fenton, David; Synnott, Hugh; Currivan, Lorraine

    2008-08-07

    The Radiological Protection Institute of Ireland (RPII) has recently completed a detailed evaluation of all radiation exposure pathways from sources of both natural and artificial radiation in the Irish environment. This paper presents a compilation of the occupational doses received by Irish workers exposed to natural sources of ionising radiation.

  7. Occupational Exposure to Natural Sources of Ionising Radiation in Ireland

    NASA Astrophysics Data System (ADS)

    Organo, Catherine; Colgan, Tony; Fenton, David; Synnott, Hugh; Currivan, Lorraine

    2008-08-01

    The Radiological Protection Institute of Ireland (RPII) has recently completed a detailed evaluation of all radiation exposure pathways from sources of both natural and artificial radiation in the Irish environment. This paper presents a compilation of the occupational doses received by Irish workers exposed to natural sources of ionising radiation.

  8. Dosimetry of ionising radiation in modern radiation oncology.

    PubMed

    Kron, Tomas; Lehmann, Joerg; Greer, Peter B

    2016-07-21

    Dosimetry of ionising radiation is a well-established and mature branch of physical sciences with many applications in medicine and biology. In particular radiotherapy relies on dosimetry for optimisation of cancer treatment and avoidance of severe toxicity for patients. Several novel developments in radiotherapy have introduced new challenges for dosimetry with small and dynamically changing radiation fields being central to many of these applications such as stereotactic ablative body radiotherapy and intensity modulated radiation therapy. There is also an increasing awareness of low doses given to structures not in the target region and the associated risk of secondary cancer induction. Here accurate dosimetry is important not only for treatment optimisation but also for the generation of data that can inform radiation protection approaches in the future. The article introduces some of the challenges and highlights the interdependence of dosimetric calculations and measurements. Dosimetric concepts are explored in the context of six application fields: reference dosimetry, small fields, low dose out of field, in vivo dosimetry, brachytherapy and auditing of radiotherapy practice. Recent developments of dosimeters that can be used for these purposes are discussed using spatial resolution and number of dimensions for measurement as sorting criteria. While dosimetry is ever evolving to address the needs of advancing applications of radiation in medicine two fundamental issues remain: the accuracy of the measurement from a scientific perspective and the importance to link the measurement to a clinically relevant question. This review aims to provide an update on both of these. PMID:27351409

  9. Dosimetry of ionising radiation in modern radiation oncology

    NASA Astrophysics Data System (ADS)

    Kron, Tomas; Lehmann, Joerg; Greer, Peter B.

    2016-07-01

    Dosimetry of ionising radiation is a well-established and mature branch of physical sciences with many applications in medicine and biology. In particular radiotherapy relies on dosimetry for optimisation of cancer treatment and avoidance of severe toxicity for patients. Several novel developments in radiotherapy have introduced new challenges for dosimetry with small and dynamically changing radiation fields being central to many of these applications such as stereotactic ablative body radiotherapy and intensity modulated radiation therapy. There is also an increasing awareness of low doses given to structures not in the target region and the associated risk of secondary cancer induction. Here accurate dosimetry is important not only for treatment optimisation but also for the generation of data that can inform radiation protection approaches in the future. The article introduces some of the challenges and highlights the interdependence of dosimetric calculations and measurements. Dosimetric concepts are explored in the context of six application fields: reference dosimetry, small fields, low dose out of field, in vivo dosimetry, brachytherapy and auditing of radiotherapy practice. Recent developments of dosimeters that can be used for these purposes are discussed using spatial resolution and number of dimensions for measurement as sorting criteria. While dosimetry is ever evolving to address the needs of advancing applications of radiation in medicine two fundamental issues remain: the accuracy of the measurement from a scientific perspective and the importance to link the measurement to a clinically relevant question. This review aims to provide an update on both of these.

  10. IEC STANDARDS FOR INDIVIDUAL MONITORING OF IONISING RADIATION

    SciTech Connect

    Voytchev, Miroslav; Ambrosi, P.; Behrens, R.; Chiaro Jr, Peter John

    2011-01-01

    This paper presents IEC/SC 45B Radiation protection instrumentation and its standards for individual monitoring of ionising radiation: IEC 61526 Ed. 3 for active personal dosemeters and IEC 62387-1 for passive integrating dosimetry systems. The transposition of these standards as CENELEC (European) standards is also discussed together with the collaboration between IEC/SC 45B and ISO/TC 85/SC 2.

  11. Resonance laser-induced ionisation of sodium vapour taking radiative transfer into account

    SciTech Connect

    Kosarev, N I; Shaparev, N Ya

    2006-04-30

    The problem of ionisation of atomic sodium in the field of resonance laser radiation is numerically solved taking radiative transfer into account. Seed electrons are produced due to the mechanism of associative ionisation, then they gain energy in superelastic processes (collisions of the second kind) and initiate the avalanche ionisation of the medium by electron impact. We studied the effect of secondary radiation on the laser pulse propagation upon competition between the ionising and quenching electron collisions with excited atoms, on the kinetics of ionisation-induced vapour bleaching, and the plasma channel expansion in the form of a halo. (interaction of laser radiation with matter)

  12. Some characteristics of the glutathione cycle revealed by ionising and non-ionising electromagnetic radiation.

    PubMed

    Holt, J A

    1995-10-01

    The cyclic reaction of GSH-->GSSG-->GSH (designated R(exp) or R(e)) obeys the three specific features of life by producing energy in exponential quantities relative to time, is in effect irreversible and is inherited from generation to generation. In multicellular life, this reaction produces the energy for mitosis and is kept in controlled inactivity until needed to maintain perfection of form and function by energising mitosis. The immediate control of Re appears to be feedback process-dependent on the concentration of GSSG. Ultra high-frequency electromagnetic radiation of 434 MHz (UHF) will change Re from inactive to active and, in so doing, it causes resonance and/or fluorescence of the glutathione cycle which changes its radiosensitivity. Re is the primary direct target of ionising radiation and produces the energy for mitosis. Clinical observations suggest that, in the normal cell, Re is inactive and is not killed by 3 x 2700 rads or 6 x 1650 rads yet, when active, its sensitivity value (DO) is approximately 160 rads. Using the standard radiobiological equation of response to ionising radiation, it can be deduced that radiosensitive cancers have two or three Re units active per cell and radioresistance increases in proportion to the number of potentially active Re units per cell. Re appears to be the main cause of cancers' increased conductivity of electricity compared with normal tissue. In cancer therapy, UHF is the best radiosensitiser ever discovered (up to two or more decades). Re is also intelligent compared with non-exponential reactions but cannot be the basis of intellectual brain functions which must be based on non-electrical chemical processes. PMID:8577298

  13. Binary-Encounter-Bethe ionisation cross sections for simulation of DNA damage by the direct effect of ionising radiation.

    PubMed

    Plante, I; Cucinotta, F A

    2015-09-01

    DNA damage is of crucial importance in the understanding of the effects of ionising radiation. To refine existing DNA damage models, an approach using the Binary-Encounter-Bethe (BEB) cross sections was developed. The differential cross sections for ionisation of the molecular orbitals of the DNA bases, sugars and phosphates are calculated using the electron binding energy, the mean kinetic energy and the occupancy number of each orbital as parameters. The resulting cross section has an analytic form which is quite convenient to use for Monte-Carlo codes that randomly sample the energy loss occurring during an ionisation event. We also describe an algorithm to simulate the interactions of electrons with DNA in the radiation transport code RITRACKS using the integrated BEB cross section for the bases, sugar and phosphates. PMID:25870431

  14. Hazards of ionising radiation: 100 years of observations on man.

    PubMed Central

    Doll, R.

    1995-01-01

    In November 1895, when Conrad Röntgen serendipitously discovered X-rays, epidemiology was effectively limited to the study of infectious disease. What little epidemiological work was done in other fields was done as part of clinical medicine or under the heading of geographical pathology. The risks from exposure to X-rays and subsequently from other types of ionising radiation were consequently discovered by qualitative association or animal experiment. They did not begin to be quantified in humans until half a century later, when epidemiology emerged as a scientific discipline capable of quantifying risks of non-infectious disease and the scientific world was alerted to the need for assessing the effects of the radiation to which large populations might be exposed by the use of nuclear energy in peace and war. PMID:8519643

  15. Occupational exposure to ionising radiation and mortality among workers of the former Spanish Nuclear Energy Board.

    PubMed Central

    Rodríguez Artalejo, F; Castaño Lara, S; de Andrés Manzano, B; García Ferruelo, M; Iglesias Martín, L; Calero, J R

    1997-01-01

    OBJECTIVES: Firstly, to ascertain whether mortality among workers of the former Spanish Nuclear Energy Board (Junta de Energía Nuclear-JEN) was higher than that for the Spanish population overall; and secondly, if this were so, to ascertain whether this difference was associated with exposure to ionising radiation. METHODS: A retrospective follow up of a cohort of 5657 workers was carried out for the period 1954-92. Cohort mortality was compared with that for the Spanish population overall, with standardised mortality ratios (SMRs) adjusted for sex, age, and calendar period. Also, Poisson models were used to analyse mortality from lung cancer in the cohort by level of exposure to ionising radiation. RESULTS: Workers' median and mean cumulative exposures were 4.04 and 11.42 mSv, respectively. Mean annual exposure was 1.33 mSv. Excess mortality due to bone tumours was found for the cohort as a whole (six deaths observed; SMR 2.95; 95% confidence interval (95% CI) 1.08 to 6.43). Among miners, excess mortality was found for non-malignant respiratory diseases (SMR 2.94; 95% CI 2.27 to 3.75), and for lung cancer bordering on statistical significance (SMR 1.50; 95% CI 0.96 to 2.23; P = 0.055). Relative risks of dying of lung cancer from ionising radiation in the dose quartiles 2, 3, and 4 versus the lowest dose quartile, were 1.00, 1.64, and 0.94, respectively. CONCLUSIONS: Excess mortality from lung cancer was found among JEN miners. Nevertheless, no clear relation was found between mortality from lung cancer and level of exposure to ionising radiation in the JEN cohort. Continued follow up of the cohort is required to confirm excess mortality from bone tumours. PMID:9155782

  16. Education and training issues in individual monitoring of ionising radiation.

    PubMed

    Dimitriou, P; Kamenopoulou, V

    2011-03-01

    The present article deals with the education and training (E&T) issues of individual monitoring (IM) of ionising radiation, based on the requirements provided by the Basic Safety Standards Euratom Directive and the European Commission Technical Recommendations for IM of external radiation. The structure and the objectives of E&T programmes addressed to the staff of dosimetry services, in order to allow the recognition and ensure the continuity of expertise are discussed. The necessity for the establishment of a national strategy for building competence in IM through information, education, training and retraining programmes, addressed to the individually monitored personnel is underlined. The train the trainers' concept is recognised as being an important tool for optimising resources and transferring the skills necessary for building competence. The conditions under which an efficient train the trainers' approach can be established are discussed. Examples of curricula concerning the key persons involved in the provision of E&T in occupational radiation protection are also given. PMID:21131663

  17. Comparison of low and high dose ionising radiation using topological analysis of gene coexpression networks

    PubMed Central

    2012-01-01

    Background The growing use of imaging procedures in medicine has raised concerns about exposure to low-dose ionising radiation (LDIR). While the disastrous effects of high dose ionising radiation (HDIR) is well documented, the detrimental effects of LDIR is not well understood and has been a topic of much debate. Since little is known about the effects of LDIR, various kinds of wet-lab and computational analyses are required to advance knowledge in this domain. In this paper we carry out an “upside-down pyramid” form of systems biology analysis of microarray data. We characterised the global genomic response following 10 cGy (low dose) and 100 cGy (high dose) doses of X-ray ionising radiation at four time points by analysing the topology of gene coexpression networks. This study includes a rich experimental design and state-of-the-art computational systems biology methods of analysis to study the differences in the transcriptional response of skin cells exposed to low and high doses of radiation. Results Using this method we found important genes that have been linked to immune response, cell survival and apoptosis. Furthermore, we also were able to identify genes such as BRCA1, ABCA1, TNFRSF1B, MLLT11 that have been associated with various types of cancers. We were also able to detect many genes known to be associated with various medical conditions. Conclusions Our method of applying network topological differences can aid in identifying the differences among similar (eg: radiation effect) yet very different biological conditions (eg: different dose and time) to generate testable hypotheses. This is the first study where a network level analysis was performed across two different radiation doses at various time points, thereby illustrating changes in the cellular response over time. PMID:22594378

  18. Single site double core level ionisation of OCS

    NASA Astrophysics Data System (ADS)

    Hedin, L.; Tashiro, M.; Linusson, P.; Eland, J. H. D.; Ehara, M.; Ueda, K.; Zhaunerchyk, V.; Karlsson, L.; Feifel, R.

    2014-08-01

    Single site O1s, C1s and S2p double ionisation of the OCS molecule has been investigated using a magnetic bottle multi-electron coincidence time-of-flight spectrometer. Photon energies of 1300, 750 and 520 eV, respectively, were used for the ionisation, and spectra were obtained from which the double core ionisation energies could be determined. The energies measured for 1s double ionisation are 1172 eV (O1s-2) and 659 eV (C1s-2). For the S2p double ionisation three dicationic states are expected, 3P, 1D and 1S. The ionisation energies obtained for these states are 373 eV (3P), 380 eV (1D) and 388 eV (1S). The ratio between the double and single core ionisation energies are in all cases equal or close to 2.20. Auger spectra of OCS, associated with the O1s-2, C1s-2 and S2p-2 dicationic states, were also recorded incorporating both electrons emitted as a result of the filling of the two core vacancies. As for other small molecules, the spectra show an atomic-like character with Auger bands located in the range 480-560 eV for oxygen, 235-295 eV for carbon and 100-160 eV for sulphur. The interpretation of the spectra is supported by CASSCF and CASCI calculations. The cross section ratio between double and single core hole creation was estimated as 3.7 × 10-4 for oxygen at 1300 eV, 3.7 × 10-4 for carbon at 750 eV and as 2.2 × 10-3 for sulphur at 520 eV.

  19. Teaching about Radioactivity and Ionising Radiation: An Alternative Approach.

    ERIC Educational Resources Information Center

    Millar, Robin; And Others

    1990-01-01

    Children's ideas about radiation and radioactivity are reviewed and several common areas of misunderstanding are identified. An approach to teaching the topic at the secondary school level which seeks to specifically address known difficulties is outlined. (CW)

  20. The risk of childhood leukaemia following exposure to ionising radiation--a review.

    PubMed

    Wakeford, Richard

    2013-03-01

    Since the early years of follow-up of the Japanese atomic-bomb survivors, it has been apparent that childhood leukaemia has a particular sensitivity to induction by ionising radiation, the excess relative risk (ERR) being expressed as a temporal wave with time since exposure. This pattern has been generally confirmed by studies of children treated with radiotherapy. Case-control studies of childhood leukaemia and antenatal exposure to diagnostic x-rays, a recent large cohort study of leukaemia following CT examinations of young people, and a recent large case-control study of natural background γ-radiation and childhood leukaemia have found evidence of raised risks following low-level exposure. These findings indicate that an ERR/Sv for childhood leukaemia of ~50, which may be derived from risk models based upon the Japanese atomic-bomb survivors, is broadly applicable to low dose or low dose-rate exposure circumstances. PMID:23296257

  1. Multidisciplinary approach to assess the sensitivity of dwarf tomato plants to low-LET ionising radiation

    NASA Astrophysics Data System (ADS)

    De Micco, Veronica; De Pascale, Stefania; Aronne, Giovanna; Paradiso, Roberta; Vitaglione, Paola; Turano, Mimmo; Arena, Carmen

    Ionising radiation, acting alone or in interaction with microgravity and other environmental constraints, may affect plant at molecular, morpho-structural and physiological level. The intensity of the plant’s response depends on the properties of radiation and on the features of the plant itself. Indeed, different species are characterised by different susceptibility to radiation which may change during the life course. The aim of this research was to study the radiosensitivity to low-LET ionising radiation of plants of dwarf tomato (Solanum lycopersicum L. ‘Microtom’) at two phenological phases (vegetative and reproductive), within the purpose of analysing plants for consideration as candidates for Bioregenerative Life Support Systems (BLSS) in Space. To pursue this objective, plants of the cultivar Microtom were irradiated with different doses of X-rays either at the stage of the second true leaf (VP - vegetative phase) or when at least one flower was blossomed (RP - reproductive phase). Plant’s response to ionising radiation was assessed through a multidisciplinary approach combining genetic analyses, ecophysiological measurements, morpho-anatomical characterisation of leaves and fruits, nutritional analyses of fruits. Growth, molecular and morpho-functional traits were measured during plant development up to fruiting in both VP and RP plant groups, and compared with non-irradiated control plants. Plant growth was monitored weekly recording parameters such as plant height, number of leaves, leaf area, flowering and fruiting rate. Potential DNA alterations were explored through Random Amplified Polymorphic DNA (RAPD) technique. The efficiency of the photosynthetic apparatus was evaluated by determining photosynthetic pigment composition, photochemistry and leaf gas exchanges. Leaf and fruit structure were analysed through light and epi-fluorescence microscopy. Leaf anatomical traits related to photosynthetic efficiency, and to structural radioprotection

  2. The biological effects of ionising radiation on Crustaceans: A review.

    PubMed

    Fuller, Neil; Lerebours, Adélaïde; Smith, Jim T; Ford, Alex T

    2015-10-01

    Historic approaches to radiation protection are founded on the conjecture that measures to safeguard humans are adequate to protect non-human organisms. This view is disparate with other toxicants wherein well-developed frameworks exist to minimise exposure of biota. Significant data gaps for many organisms, coupled with high profile nuclear incidents such as Chernobyl and Fukushima, have prompted the re-evaluation of our approach toward environmental radioprotection. Elucidating the impacts of radiation on biota has been identified as priority area for future research within both scientific and regulatory communities. The crustaceans are ubiquitous in aquatic ecosystems, comprising greater than 66,000 species of ecological and commercial importance. This paper aims to assess the available literature of radiation-induced effects within this subphylum and identify knowledge gaps. A literature search was conducted pertaining to radiation effects on four endpoints as stipulated by a number of regulatory bodies: mortality, morbidity, reproduction and mutation. A major finding of this review was the paucity of data regarding the effects of environmentally relevant radiation doses on crustacean biology. Extremely few studies utilising chronic exposure durations or wild populations were found across all four endpoints. The dose levels at which effects occur was found to vary by orders of magnitude thus presenting difficulties in developing phyla-specific benchmark values and reference levels for radioprotection. Based on the limited data, mutation was found to be the most sensitive endpoint of radiation exposure, with mortality the least sensitive. Current phyla-specific dose levels and limits proposed by major regulatory bodies were found to be inadequate to protect species across a range of endpoints including morbidity, mutation and reproduction and examples are discussed within. These findings serve to prioritise areas for future research that will significantly

  3. Genotoxicity in earthworm after combined treatment of ionising radiation and mercury.

    PubMed

    Ryu, Tae Ho; An, Kwang-Guk; Kim, Jin Kyu

    2014-06-01

    This study was performed to investigate the acute genotoxic effects of mercury and radiation on earthworms (Eisenia fetida). The levels of DNA damage and the repair kinetics in the coelomocytes of E. fetida treated with mercuric chloride (HgCl₂) and ionising radiation (gamma rays) were analysed by means of the comet assay. For detection of DNA damage and repair, E. fetida was exposed to HgCl₂ (0-160 mg kg(-1)) and irradiated with gamma rays (0-50 Gy) in vivo. The increase in DNA damage depended on the concentration of mercury or dose of radiation. The results showed that the more the oxidative stress induced by mercury and radiation the longer the repair time that was required. When a combination of HgCl₂ and gamma rays was applied, the cell damage was much higher than those treated with HgCl₂ or radiation alone, which indicated that the genotoxic effects were increased after the combined treatment of mercury and radiation. PMID:24870361

  4. Comparison of precise ionising Radiation Dose Measurements on board Aircraft

    NASA Astrophysics Data System (ADS)

    Lindborg, L.; Beck, P.; Bottollier, J. F.; Roos, H.; Spurny, F.; Wissman, F.

    2003-04-01

    The cosmic radiation makes aircrew one of the most exposed occupational groups. The European Council has therefore in its Directive 96/29Euratom on basic safety standards for radiation protection a particular article (42) for the protection of aircrew. One of the measures to be taken is to assess the exposure of the crew. This is, however, not a trivial task. The radiation consists of many different types of radiation with energies that are hardly met on ground. The knowledge on the dose levels on board aircraft has improved gradually during the last decade as several groups around the world have performed measurements on board civil aircraft in cooperation with airlines. Only occasionally has more than one instrument been able to fly at the same time for practical reasons. The statistical uncertainty in a measurement of the dose equivalent rate is typically ±15 % (1 relative standard deviation) if determined during half an hour. Systematic uncertainties add to this. The dose rate depends on flight altitude, geographic coordinates of the flight, the phase of the solar cycle and the prevailing solar wind. For that reason the possibility to fly on the same flight will eliminate some of the systematic uncertainties that limits an evaluation of the measurement techniques. The proposal aims at measurements on board the aircraft on a geographically limited area for a few hours to decrease the statistical uncertainty of the measurements and thereby get an excellent opportunity to look for possible systematic differences between the different measurement systems. As the dose equivalent rate will be quite well established it will also be possible to compare the measured values with calculated ones. The dose rate increases towards the geomagnetic poles and decreases towards the equator. The composition of the radiation components varies also with altitude. For that reason measurements both at southern latitude and at northern latitude are planned.

  5. Destruction of Raman biosignatures by ionising radiation and the implications for life detection on Mars.

    PubMed

    Dartnell, Lewis R; Page, Kristian; Jorge-Villar, Susana E; Wright, Gary; Munshi, Tasnim; Scowen, Ian J; Ward, John M; Edwards, Howell G M

    2012-04-01

    Raman spectroscopy has proven to be a very effective approach for the detection of microorganisms colonising hostile environments on Earth. The ExoMars rover, due for launch in 2018, will carry a Raman laser spectrometer to analyse samples of the martian subsurface collected by the probe's 2-m drill in a search for similar biosignatures. The martian surface is unprotected from the flux of cosmic rays, an ionising radiation field that will degrade organic molecules and so diminish and distort the detectable Raman signature of potential martian microbial life. This study employs Raman spectroscopy to analyse samples of two model organisms, the cyanobacterium Synechocystis sp. PCC 6803 and the extremely radiation resistant polyextremophile Deinococcus radiodurans, that have been exposed to increasing doses of ionising radiation. The three most prominent peaks in the Raman spectra are from cellular carotenoids: deinoxanthin in D. radiodurans and β-carotene in Synechocystis. The degradative effect of ionising radiation is clearly seen, with significant diminishment of carotenoid spectral peak heights after 15 kGy and complete erasure of Raman biosignatures by 150 kGy of ionising radiation. The Raman signal of carotenoid in D. radiodurans diminishes more rapidly than that of Synechocystis, believed to be due to deinoxanthin acting as a superior scavenger of radiolytically produced reactive oxygen species, and so being destroyed more quickly than the less efficient antioxidant β-carotene. This study highlights the necessity for further experimental work on the manner and rate of degradation of Raman biosignatures by ionising radiation, as this is of prime importance for the successful detection of microbial life in the martian near subsurface. PMID:22349404

  6. Ionising Radiation Exposure to Orthopaedic Trainees: The Effect of Sub-Specialty Training

    PubMed Central

    Oddy, MJ; Aldam, CH

    2006-01-01

    INTRODUCTION We monitored image intensifier use by orthopaedic trainees to assess their exposure to ionising radiation and to investigate the influence of sub-specialty training. MATERIALS AND METHODS Five different orthopaedic registrars recorded their monthly image intensifier screening times and exposure doses for all cases (trauma and elective), for a combined total of 12 non-consecutive months. Radiation exposure was monitored using shoulder and waist film badges worn both by surgeons and radiographers screening their cases. RESULTS Registrars in spinal sub-specialties were exposed to significantly higher doses per case and cumulative doses per month than non-spinal trainees (P < 0.05), but significantly lower screening times per case (P < 0.05). There were no significant differences in cumulative screening times per month (P > 0.05). Regression analysis for all surgeons showed a significant relationship between shoulder film badge reading and cumulative dose exposed per month (P < 0.05), but not for cumulative screening time. Shoulder film badge recordings were significantly higher for spinal compared with non-spinal registrars (P < 0.05), although all badges were below the level for radiation reporting. Only one radiographer badge recorded a dose above threshold. CONCLUSIONS Whilst the long-term effects of sub-reporting doses of radiation are not fully understood, we consider that this study demonstrates that trainees should not be complacent in accepting inadequate radiation protection. The higher doses encountered with spinal imaging means that sub-specialty trainees should be alerted to the risk of their increased exposure. The principle of minimising radiation exposure must be maintained by all trainees at all times. PMID:16720002

  7. Leaf Anatomy and Photochemical Behaviour of Solanum lycopersicum L. Plants from Seeds Irradiated with Low-LET Ionising Radiation

    PubMed Central

    De Micco, V.; Paradiso, R.; Aronne, G.; De Pascale, S.; Quarto, M.; Arena, C.

    2014-01-01

    Plants can be exposed to ionising radiation not only in Space but also on Earth, due to specific technological applications or after nuclear disasters. The response of plants to ionising radiation depends on radiation quality/quantity and/or plant characteristics. In this paper, we analyse some growth traits, leaf anatomy, and ecophysiological features of plants of Solanum lycopersicum L. “Microtom” grown from seeds irradiated with increasing doses of X-rays (0.3, 10, 20, 50, and 100 Gy). Both juvenile and compound leaves from plants developed from irradiated and control seeds were analysed through light and epifluorescence microscopy. Digital image analysis allowed quantifying anatomical parameters to detect the occurrence of signs of structural damage. Fluorescence parameters and total photosynthetic pigment content were analysed to evaluate the functioning of the photosynthetic machinery. Radiation did not affect percentage and rate of seed germination. Plants from irradiated seeds accomplished the crop cycle and showed a more compact habitus. Dose-depended tendencies of variations occurred in phenolic content, while other leaf anatomical parameters did not show distinct trends after irradiation. The sporadic perturbations of leaf structure, observed during the vegetative phase, after high levels of radiation were not so severe as to induce any significant alterations in photosynthetic efficiency. PMID:24883400

  8. EURADOS strategic research agenda: vision for dosimetry of ionising radiation.

    PubMed

    Rühm, W; Fantuzzi, E; Harrison, R; Schuhmacher, H; Vanhavere, F; Alves, J; Bottollier Depois, J F; Fattibene, P; Knežević, Ž; Lopez, M A; Mayer, S; Miljanić, S; Neumaier, S; Olko, P; Stadtmann, H; Tanner, R; Woda, C

    2016-02-01

    Since autumn 2012, the European Radiation Dosimetry Group (EURADOS) has been developing its Strategic Research Agenda (SRA), which is intended to contribute to the identification of future research needs in radiation dosimetry in Europe. The present article summarises-based on input from EURADOS Working Groups (WGs) and Voting Members-five visions in dosimetry and defines key issues in dosimetry research that are considered important for the next decades. The five visions include scientific developments required towards (a) updated fundamental dose concepts and quantities, (b) improved radiation risk estimates deduced from epidemiological cohorts, (c) efficient dose assessment for radiological emergencies, (d) integrated personalised dosimetry in medical applications and (e) improved radiation protection of workers and the public. The SRA of EURADOS will be used as a guideline for future activities of the EURADOS WGs. A detailed version of the SRA can be downloaded as a EURADOS report from the EURADOS website (www.eurados.org). PMID:25752758

  9. Radiation safety in the nuclear medicine department: impact of the UK Ionising Radiations Regulations.

    PubMed

    Harding, L K

    1987-09-01

    The practice of nuclear medicine requires integration of radiation safety with patient care and radiopharmaceutical standards. Nationally there was useful discussion in the UK before the Ionising Radiations Regulations and Approved Code of Practice were published, although such consultation had been lacking when the Medicines Act was implemented. Most of the new considerations relating to nuclear medicine stem from Schedule 6 of the Regulations. Generally, the presence of a single patient does not require a controlled area. However, when several patients are present, or radiopharmaceuticals are being prepared prior to injection, a controlled area is required. Classification of workers is not likely to be required in a typical nuclear medicine department in the UK, although most parts of the nuclear medicine department will need to be controlled areas. These include the radiopharmacy, radionuclide dispensary, injection room, and imaging rooms if patients are injected in them. The importance of finger dose measurements is emphasised. Patient wards, however, need not be controlled areas. A particular concern in nuclear medicine was that patients should not need to be admitted to hospital merely to comply with legislation. This is possibly the case and clarification will probably be available when the Notes for Guidance are published. Most procedures in nuclear medicine departments will remain unchanged. Further information is required, however, on patient waiting rooms, handling flood sources, pregnancy, and breast feeding. Within the hospital, detailed and multidisciplinary discussion will need to take place within the forum of the radiation safety committee. PMID:3664186

  10. Xpg limits the expansion of haematopoietic stem and progenitor cells after ionising radiation.

    PubMed

    Avila, Alush I; Illing, Anett; Becker, Friedrich; Maerz, Lars D; Morita, Yohei; Philipp, Melanie; Burkhalter, Martin D

    2016-07-27

    Reduced capacity of genome maintenance represents a problem for any organism, potentially causing premature death, carcinogenesis, or accelerated ageing. Strikingly though, loss of certain genome stability factors can be beneficial, especially for the maintenance of tissue stem cells of the intestine and the haematopoietic system. We therefore screened for genome stability factors negatively impacting maintenance of haematopoietic stem cells (HSC) in the context of ionising radiation (IR). We found that in vivo knock down of Xeroderma pigmentosum, complementation group G (Xpg) causes elevation of HSC numbers after IR treatment, while numbers of haematopoietic progenitors are elevated to a lesser extent. IR rapidly induces Xpg both on mRNA and on protein level. Prevention of this induction does not influence activation of the checkpoint cascade, yet attenuates late checkpoint steps such as induction of p21 and Noxa. This causes a leaky cell cycle arrest and lower levels of apoptosis, both contributing to increased colony formation and transformation rates. Xpg thus helps to adequately induce DNA damage responses after IR, thereby keeping the expansion of damaged cells under control. This represents a new function of Xpg in the response to IR, in addition to its well-characterized role in nucleotide excision repair. PMID:27137888

  11. Non-targeted effects of ionising radiation and radiotherapy.

    PubMed

    Sjostedt, Svetlana; Bezak, Eva

    2010-09-01

    Modern radiobiology is undergoing rapid change due to new discoveries contradicting the target concept which is currently used to predict dose-response relationships. Thus relatively recently discovered radiation-induced bystander effects (RIBEs), that include additional death, mutation and radio-adaptation in non-irradiated cells, change our understanding of the target concept and broadens its boundaries. This can be significant from a radioprotection point of view and also has the potential to reassess radiation damage models currently used in radiotherapy. This article reviews briefly the general concepts of RIBEs such as the proposed underlying mechanisms of signal induction and propagation, experimental approaches and biological end points used to investigate these phenomena. It also summarises several mathematical models currently proposed in an attempt to quantify RIBE. The main emphasis of this article is to review and highlight the potential impact of the bystander phenomena in radiotherapy. PMID:20857259

  12. Internet-based ICRP resource for healthcare providers on the risks and benefits of medical imaging that uses ionising radiation.

    PubMed

    Demeter, S; Applegate, K E; Perez, M

    2016-06-01

    The purpose of the International Commission on Radiological Protection (ICRP) Committee 3 Working Party was to update the 2001 web-based module 'Radiation and your patient: a guide for medical practitioners' from ICRP. The key elements of this task were: to clearly identify the target audience (such as healthcare providers with an emphasis on primary care); to review other reputable sources of information; and to succinctly publish the contribution made by ICRP to the various topics. A 'question-and-answer' format addressing practical topics was adopted. These topics included benefits and risks of imaging using ionising radiation in common medical situations, as well as pertaining to specific populations such as pregnant, breast-feeding, and paediatric patients. In general, the benefits of medical imaging and related procedures far outweigh the potential risks associated with ionising radiation exposure. However, it is still important to ensure that the examinations are clinically justified, that the procedure is optimised to deliver the lowest dose commensurate with the medical purpose, and that consideration is given to diagnostic reference levels for particular classes of examinations. PMID:27012846

  13. EVOLUTION OF THE IEC AND EN STANDARDS FOR INDIVIDUAL MONITORING OF IONISING RADIATION.

    PubMed

    Voytchev, M; Behrens, R; Ambrosi, P; Radev, R; Chiaro, P

    2016-09-01

    This article presents the evolution of the International Electrotechnical Commission (IEC) and the European standards for individual monitoring of ionising radiation issued, respectively, from the committees IEC/Sub Committee 45B and European Committee for Electro-technical Standardization/Technical Committee 45B 'Radiation protection instrumentation'. Standards for passive individual photon and beta dosimetry systems as well as those for active individual monitors are discussed. A neutron ambient dose equivalent (rate) meter standard and a technical report concerning the determination of uncertainty in measurement are also covered. PMID:26443545

  14. The perturbation correction factor of ionisation chambers in beta-radiation fields.

    PubMed

    Böhm, J

    1980-01-01

    In determining the absorbed dose in a solid medium by means of gas-filled ionisation chambers, the perturbation of the radiation field by the chamber needs to be taken into account. So far, an appropriate correction factor has neither been calculated nor measured for beta-radiation. This work describes its experimental determination for an extrapolation chamber and beta-radiation fields of 147Pm, 204Tl, and 90Sr + 90Y. The results show that the correction factor may be assumed to be the product of a shield factor and a scatter factor the magnitudes of which depend on the chamber geometry and the radiation field. The change of the perturbation correction factor with phantom depth is important for the measurement of depth dose curves. This is demonstrated by an example. PMID:7360793

  15. Radiation in the workplace-a review of studies of the risks of occupational exposure to ionising radiation.

    PubMed

    Wakeford, Richard

    2009-06-01

    Many individuals are, or have been, exposed to ionising radiation in the course of their work and the epidemiological study of occupationally irradiated groups offers an important opportunity to complement the estimates of risks to health resulting from exposure to radiation that are obtained from other populations, such as the Japanese survivors of the atomic bombings of Hiroshima and Nagasaki in 1945. Moreover, workplace exposure to radiation usually involves irradiation conditions that are of direct relevance to the principal concern of radiological protection: protracted exposure to low level radiation. Further, some workers have been exposed to radioactive material that has been inadvertently taken into the body, and the study of these groups leads to risk estimates derived directly from the experience of those irradiated by these 'internal emitters', intakes of alpha-particle-emitters being of particular interest. Workforces that have been the subject of epidemiological study include medical staff, aircrews, radium dial luminisers, underground hard-rock miners, Chernobyl clean-up workers, nuclear weapons test participants and nuclear industry workers. The first solid epidemiological evidence of the stochastic effects of irradiation came from a study of occupational exposure to medical x-rays that was reported in 1944, which demonstrated a large excess risk of leukaemia among US radiologists; but the general lack of dose records for early medical staff who tended to experience the highest exposures hampers the derivation of risks per unit dose received by medical workers. The instrument dial luminisers who inadvertently ingested large amounts of radium-based paint and underground hard-rock miners who inhaled large quantities of radon and its decay products suffered markedly raised excess risks of, respectively, bone and lung cancers; the miner studies have provided standard risk estimates for radon-induced lung cancer. The large numbers of nuclear industry

  16. Adaptive response to ionising radiation induced by cadmium in zebrafish embryos.

    PubMed

    Choi, V W Y; Ng, C Y P; Kong, M K Y; Cheng, S H; Yu, K N

    2013-03-01

    An adaptive response is a biological response where the exposure of cells or animals to a low priming exposure induces mechanisms that protect the cells or animals against the detrimental effects of a subsequent larger challenging exposure. In realistic environmental situations, living organisms can be exposed to a mixture of stressors, and the resultant effects due to such exposures are referred to as multiple stressor effects. In the present work we demonstrated, via quantification of apoptosis in the embryos, that embryos of the zebrafish (Danio rerio) subjected to a priming exposure provided by one environmental stressor (cadmium in micromolar concentrations) could undergo an adaptive response against a subsequent challenging exposure provided by another environmental stressor (alpha particles). We concluded that zebrafish embryos treated with 1 to 10 μM Cd at 5 h postfertilisation (hpf) for both 1 and 5 h could undergo an adaptive response against subsequent ~4.4 mGy alpha-particle irradiation at 10 hpf, which could be interpreted as an antagonistic multiple stressor effect between Cd and ionising radiation. The zebrafish has become a popular vertebrate model for studying the in vivo response to ionising radiation. As such, our results suggested that multiple stressor effects should be carefully considered for human radiation risk assessment since the risk may be perturbed by another environmental stressor such as a heavy metal. PMID:23296313

  17. Glioblastoma stem cells: radiobiological response to ionising radiations of different qualities.

    PubMed

    Pecchia, I; Dini, V; Ricci-Vitiani, L; Biffoni, M; Balduzzi, M; Fratini, E; Belli, M; Campa, A; Esposito, G; Cirrone, G; Romano, F; Stancampiano, C; Pelacchi, F; Pallini, R; Tabocchini, M A

    2015-09-01

    Glioblastoma multiforme (GBM) is the most common and malignant primary brain tumour, with very poor prognosis. The high recurrence rate and failure of conventional treatments are expected to be related to the presence of radio-resistant cancer stem cells (CSCs) inside the tumour mass. CSCs can both self-renew and differentiate into the heterogeneous lineages of cancer cells. Recent evidence showed a higher effectiveness of C-ions and protons in inactivating CSCs, suggesting a potential advantage of Hadrontherapy compared with conventional radiotherapy for GBM treatment. To investigate the mechanisms involved in the molecular and cellular responses of CSCs to ionising radiations, two GBM stem cell (GSC) lines, named lines 1 and 83, which were derived from patients with different clinical outcomes and having different metabolic profiles (as shown by NMR spectroscopy), were irradiated with (137)Cs photons and with protons or C-ions of 62 MeV u(-1) in the dose range of 5-40 Gy. The biological effects investigated were: cell death, cell cycle progression, and DNA damage induction and repair. Preliminary results show a different response to ionising radiation between the two GSC lines for the different end points investigated. Further experiments are in progress to consolidate the data and to get more insights on the influence of radiation quality. PMID:25969527

  18. Preparation of (K:Eu) NaSO4 phosphor for lyoluminescence dosimetry of ionising radiation.

    PubMed

    Dhoble, S J

    2002-01-01

    Gamma ray dosimetry using lyoluminescence is a low cost and simple system. As sulphate based phosphors are used for TL radiation dosimetry they therefore seem to be a promising material for LL gamma ray dosimetry. A study on LL properties of Eu activated KNaSO4 and K3Na(SO4)2 gamma irradiated materials is reported. Eu doped KNaSO4 shows maximum LL yield in the above system. It shows a linear response from 0.06 to 10 C.kg(-1) and there is not much fading of LL intensity, indicating the phosphor to be suitable as a lyoluminescence dosimetry phosphor of ionising radiation. The doped Eu ion acts as an activator and thus enhances the LL intensity of the phosphor. PMID:12382879

  19. Low-dose ionising radiation and cardiovascular diseases--Strategies for molecular epidemiological studies in Europe.

    PubMed

    Kreuzer, Michaela; Auvinen, Anssi; Cardis, Elisabeth; Hall, Janet; Jourdain, Jean-Rene; Laurier, Dominique; Little, Mark P; Peters, Annette; Raj, Ken; Russell, Nicola S; Tapio, Soile; Zhang, Wei; Gomolka, Maria

    2015-01-01

    It is well established that high-dose ionising radiation causes cardiovascular diseases. In contrast, the evidence for a causal relationship between long-term risk of cardiovascular diseases after moderate doses (0.5-5 Gy) is suggestive and weak after low doses (<0.5 Gy). However, evidence is emerging that doses under 0.5 Gy may also increase long-term risk of cardiovascular disease. This would have major implications for radiation protection with respect to medical use of radiation for diagnostic purposes and occupational or environmental radiation exposure. Therefore, it is of great importance to gain information about the presence and possible magnitude of radiation-related cardiovascular disease risk at doses of less than 0.5 Gy. The biological mechanisms implicated in any such effects are unclear and results from epidemiological studies are inconsistent. Molecular epidemiological studies can improve the understanding of the pathogenesis and the risk estimation of radiation-induced circulatory disease at low doses. Within the European DoReMi (Low Dose Research towards Multidisciplinary Integration) project, strategies to conduct molecular epidemiological studies in this field have been developed and evaluated. Key potentially useful European cohorts are the Mayak workers, other nuclear workers, uranium miners, Chernobyl liquidators, the Techa river residents and several diagnostic or low-dose radiotherapy patient cohorts. Criteria for informative studies are given and biomarkers to be investigated suggested. A close collaboration between epidemiology, biology and dosimetry is recommended, not only among experts in the radiation field, but also those in cardiovascular diseases. PMID:26041268

  20. Age at exposure to ionising radiation and cancer mortality among Hanford workers: follow up through 1994

    PubMed Central

    Wing, S; Richardson, D

    2005-01-01

    Background: Studies of workers at the plutonium production factory in Hanford, WA have led to conflicting conclusions about the role of age at exposure as a modifier of associations between ionising radiation and cancer. Aims: To evaluate the influence of age at exposure on radiation risk estimates in an updated follow up of Hanford workers. Methods: A cohort of 26 389 workers hired between 1944 and 1978 was followed through 1994 to ascertain vital status and causes of death. External radiation dose estimates were derived from personal dosimeters. Poisson regression was used to estimate associations between mortality and cumulative external radiation dose at all ages, and in specific age ranges. Results: A total of 8153 deaths were identified, 2265 of which included cancer as an underlying or contributory cause. Estimates of the excess relative risk per Sievert (ERR/Sv) for cumulative radiation doses at all ages combined were negative for all cause and leukaemia and positive for all cancer and lung cancer. Cumulative doses accrued at ages below 35, 35–44, and 45–54 showed little association with mortality. For cumulative dose accrued at ages 55 and above (10 year lag), the estimated ERR/Sv for all cancers was 3.24 (90% CI: 0.80 to 6.17), primarily due to an association with lung cancer (ERR/Sv: 9.05, 90% CI: 2.96 to 17.92). Conclusions: Associations between radiation and cancer mortality in this cohort are primarily a function of doses at older ages and deaths from lung cancer. The association of older age radiation exposures and cancer mortality is similar to observations from several other occupational studies. PMID:15961623

  1. Risk of cancer after low doses of ionising radiation: retrospective cohort study in 15 countries

    PubMed Central

    Cardis, E; Vrijheid, M; Blettner, M; Gilbert, E; Hakama, M; Hill, C; Howe, G; Kaldor, J; Muirhead, C R; Schubauer-Berigan, M; Yoshimura, T; Bermann, F; Cowper, G; Fix, J; Hacker, C; Heinmiller, B; Marshall, M; Thierry-Chef, I; Utterback, D; Ahn, Y-O; Amoros, E; Ashmore, P; Auvinen, A; Bae, J-M; Solano, J Bernar; Biau, A; Combalot, E; Deboodt, P; Sacristan, A Diez; Eklof, M; Engels, H; Engholm, G; Gulis, G; Habib, R; Holan, K; Hyvonen, H; Kerekes, A; Kurtinaitis, J; Malker, H; Martuzzi, M; Mastauskas, A; Monnet, A; Moser, M; Pearce, M S; Richardson, D B; Rodriguez-Artalejo, F; Rogel, A; Tardy, H; Telle-Lamberton, M; Turai, I; Usel, M; Veress, K

    2005-01-01

    Objectives To provide direct estimates of risk of cancer after protracted low doses of ionising radiation and to strengthen the scientific basis of radiation protection standards for environmental, occupational, and medical diagnostic exposures. Design Multinational retrospective cohort study of cancer mortality. Setting Cohorts of workers in the nuclear industry in 15 countries. Participants 407 391 workers individually monitored for external radiation with a total follow-up of 5.2 million person years. Main outcome measurements Estimates of excess relative risks per sievert (Sv) of radiation dose for mortality from cancers other than leukaemia and from leukaemia excluding chronic lymphocytic leukaemia, the main causes of death considered by radiation protection authorities. Results The excess relative risk for cancers other than leukaemia was 0.97 per Sv, 95% confidence interval 0.14 to 1.97. Analyses of causes of death related or unrelated to smoking indicate that, although confounding by smoking may be present, it is unlikely to explain all of this increased risk. The excess relative risk for leukaemia excluding chronic lymphocytic leukaemia was 1.93 per Sv (< 0 to 8.47). On the basis of these estimates, 1-2% of deaths from cancer among workers in this cohort may be attributable to radiation. Conclusions These estimates, from the largest study of nuclear workers ever conducted, are higher than, but statistically compatible with, the risk estimates used for current radiation protection standards. The results suggest that there is a small excess risk of cancer, even at the low doses and dose rates typically received by nuclear workers in this study. PMID:15987704

  2. Effect of penetrating ionising radiation on the mechanical properties of pericardium

    NASA Astrophysics Data System (ADS)

    Daar, Eman; Woods, E.; Keddie, J. L.; Nisbet, A.; Bradley, D. A.

    2010-07-01

    The pericardium is an anistropic composite material made up of collagen and elastin fibres embedded in an amorphous matrix mainly composed of proteoglycan and hyaluronan. The collagen fibres are arranged in layers, with different directions of alignment in each layer, giving rise to interesting mechanical properties of pericardium, including the ability to undergo large deformation during performance of regular physiological functions. The present study aims to investigate the effect of penetrating photon ionising radiation on bovine pericardium tissue, being part of a study of the effect of cardiac doses received in breast radiotherapy and the possibility that this can give rise to cardiovascular complications. Irradiation doses in the range 5-80 Gy were used. To characterise the various mechanical properties [elastic modulus, stress relaxation, ultimate tensile strength (UTS) and fracture] a uniaxial tensile test method was applied. The preliminary results reflect the wide inter-sample variations that are expected in dealing with tissues, with only a weak indication of increase in the UTS of the pericardium tissue with increase in radiation dose. Such an effect has also been observed by others, with reduction in UTS at doses of 80 Gy.

  3. Probing Radiation Damage at the Molecular Level

    NASA Astrophysics Data System (ADS)

    Mason, N. J.; Smialek, M. A.; Moore, S. A.; Folkard, M.; Hoffmann, S. V.

    2006-12-01

    Radiation damage of DNA and other cellular components has traditionally been attributed to ionisation via direct impact of high-energy quanta or by complex radical chemistry. However recent research has shown that strand breaks in DNA may be initiated by secondary electrons and is strongly dependent upon the target DNA base identity. Such research provides the fascinating perspective that it is possible that radiation damage may be described and understood at an individual molecular level introducing new possibilites for therapy and perhaps providing an insight into the origins of life.

  4. Calibration, performance and type testing of personal dosemeters used in ionising-radiation applications in Greece.

    PubMed

    Boziari, A; Hourdakis, C J

    2007-01-01

    Active Personal Dosemeters (APDs) are widely used in real-time personal dosimetry. Their performance, operational characteristics and limitations, as well as their calibration should be routinely checked to assure satisfactory operation and safe use. This study summarises the results of such type tests and calibrations performed in almost 4750 dosemeters at Ionising Radiation Calibration Laboratory (HIRCL) of Greek Atomic Energy Commission (GAEC). About 13.8% of the pencil type and 4.3% of the electronic dosemeters were found to be out of limits of acceptable performance. For the pencil type dosemeters, the mean calibration factor (CF+/-SD) for high- and low-dose categories was found to be 1.014+/-0.102 (range 0.793-1.458) and 0.995+/-0.059 (range 0.794-1.311), respectively. Of these >85% of them had reproducibility better than 90%, while <1% showed remarkable non-linearity and approximately 10% of them failed to retain the dose reading within the limits after 24 h. For the electronic dosemeters, the mean CF was 1.034+/-0.046 (range 0.967-1.238). The majority of them showed good reproducibility and linearity results while, after irradiation, the dose readings were not shifted through time. The energy response varies with the dosemeter type, reaching in one dosemeter type down to 50%. Both electronic and pencil did not showed electronic equilibrium problems. PMID:17185312

  5. An isotopic analysis of ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-06-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find an enrichment factor (δ34S) of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  6. An isotope view on ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-02-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find a δ34S value of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  7. An isotopic view of ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S. O.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-04-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism remains undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find a d34S value of 8.7 ± 0.4 ‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  8. Resveratrol and its methoxy-derivatives as modulators of DNA damage induced by ionising radiation.

    PubMed

    Traversi, Gianandrea; Fiore, Mario; Leone, Stefano; Basso, Emiliano; Di Muzio, Elena; Polticelli, Fabio; Degrassi, Francesca; Cozzi, Renata

    2016-07-01

    Various naturally occurring stilbene-like compounds that are related to resveratrol (RSV) possess some of the beneficial effects of the parent molecule and provide even further benefits. Therefore, a series of methoxylated analogues of RSV were prepared with the aim of increasing antitumour and proapoptotic activity. In a previous article, we studied two methoxy-derivatives, pterostilbene (PTERO) and trimethoxystilbene (TRIMETHOXY), in which the first was formed by the substitution of two hydroxyl groups with two methoxy groups (trans-3,5-dimethoxy-4'-hydroxystilbene) and the second was formed by the replacement of all three OH groups with methoxy groups (trans-3,5,4'-trimethoxystilbene). Both methoxy-derivatives showed stronger antioxidant activity when compared with RSV. In the present article, we focused on the analysis of the ability of RSV and its two methoxylated derivatives to protect proliferating non-tumoural cells from the damage induced by ionising radiation (IR). First we showed that the methoxy derivatives, contrary to their parental compound, are unable to affect topoisomerase enzyme and consequently are not clastogenic per se Second we showed that both PTERO and TRIMETHOXY more efficiently reduce the chromosome damage induced by IR. Furthermore, TRIMETHOXY, but not PTERO, causes a delay in cell proliferation, particularly in mitosis progression increasing the number of cells in metaphase at the expense of prophases and ana/telophases. PMID:26819346

  9. [Low dose ionising radiation and cancer: findings and methods. Report of a meeting and consequences for Switzerland].

    PubMed

    Schüler, G; Gutzwiller, F

    1991-01-01

    Today's society is concerned about the dangers of ionising radiation, especially in the aftermath of Chernobyl. On the other hand, there exists a widespread lack of understanding radiation biology and radioepidemiology--the very sciences which provide the data from which today's risk estimates have been derived. The papers in this issue of the Journal were presented at a workshop on "Low level radiation and cancer: data and methods" held on 10th-11th December in Feuisberg, near Zurich. The meeting was organised by the Institute of Social and Preventive Medicine of the University of Zurich under the auspices of the Swiss Federal Office of Public Health. Its aims were threefold. First, to give an introduction to some basic facts and methodological issues in radiation physics, biology and epidemiology. Secondly, to give an overview of the availability of data for radioepidemiological research in Switzerland and, thirdly, to evaluate possible research strategies in this country. A list of some notions and units commonly used in the radiation sciences serves an an introduction to the field (G. Schüler et al.). In using units and notions it is important to distinguish the description of biological experiments and epidemiological observations from definitions and risk projections proposed by international reports and consensus bodies for radioprotection purposes. The next papers deal more specifically with selected aspects of the basic sciences. Dosimetry means quantifying the physical effects of ionizing radiation in human tissue; this is not a straight-forward procedure (I. Cordt). The foundations of general radiation biology are succinctly summarised by C. Michel. An account of our present knowledge and theories of radiation carcinogenesis is provided by W. Burkart. W Lutz compares dose-response models of chemical carcinogenesis with those used in radiation carcinogenesis. During the last decade the epidemiological foundations of radioprotection have changed

  10. The multiple stressor effect in zebrafish embryos from simultaneous exposure to ionising radiation and cadmium.

    PubMed

    Ng, C Y P; Choi, V W Y; Lam, A C L; Cheng, S H; Yu, K N

    2013-03-01

    Living organisms are exposed to a mixture of environmental stressors, and the resultant effects are referred to as multiple stressor effects. In the present work, we studied the multiple stressor effect in embryos of the zebrafish (Danio rerio) from simultaneous exposure to ionising radiation (alpha particles) and cadmium through quantification of apoptotic signals at 24 h postfertilisation (hpf) revealed by vital dye acridine orange staining. For each set of experiments, 32-40 dechorionated embryos were deployed, which were divided into four groups each having 8-10 embryos. The four groups of embryos were referred to as (1) the control group (C), which received no further treatments after dechorionation; (2) the Cd-dosed and irradiated group (CdIr), which was exposed to 100 μM Cd from 5 to 24 hpf, and also received about 4.4 mGy from alpha particles at 5 hpf; (3) the irradiated group (Ir), which received about 4.4 mGy from alpha particles at 5 hpf; and (4) the Cd-dosed group (Cd), which was exposed to 100 μM Cd from 5 to 24 hpf. In general, the CdIr, Ir and Cd groups had more apoptotic signals than the C group. Within the 12 sets of experimental results, two showed significant synergistic effects, one showed a weakly synergistic effect and nine showed additive effects. The multiple stressor effect of 100 μM Cd with ~4.4 mGy alpha-particle radiation resulted in an additive or synergistic effect, but no antagonistic effect. The failure to identify significant synergistic effects for some sets of data, and thus their subsequent classification as additive effects, might be a result of the relatively small magnitude of the synergistic effects. The results showed that the radiation risk could be perturbed by another environmental stressor such as a heavy metal, and as such a realistic human radiation risk assessment should in general take into account the multiple stressor effects. PMID:23296360

  11. Laser ablation and ionisation by laser plasma radiation in the atmospheric-pressure mass spectrometry of organic compounds

    SciTech Connect

    Pento, A V; Nikiforov, S M; Simanovsky, Ya O; Grechnikov, A A; Alimpiev, S S

    2013-01-31

    A new method was developed for the mass spectrometric analysis of organic and bioorganic compounds, which involves laser ablation with the ionisation of its products by laser-plasma radiation and enables analysing gaseous, liquid, and solid substances at atmospheric pressure without sample preparation. The capabilities of this method were demonstrated by the examples of fast pharmaceutical composition screening, real-time atmosphere composition analysis, and construction of the mass spectrometric images of organic compound distributions in biological materials. (interaction of laser radiation with matter)

  12. Ionising Radiation Immediately Impairs Synaptic Plasticity-Associated Cytoskeletal Signalling Pathways in HT22 Cells and in Mouse Brain: An In Vitro/In Vivo Comparison Study

    PubMed Central

    Kempf, Stefan J.; Buratovic, Sonja; von Toerne, Christine; Moertl, Simone; Stenerlöw, Bo; Hauck, Stefanie M.; Atkinson, Michael J.; Eriksson, Per; Tapio, Soile

    2014-01-01

    Patients suffering from brain malignancies are treated with high-dose ionising radiation. However, this may lead to severe learning and memory impairment. Preventive treatments to minimise these side effects have not been possible due to the lack of knowledge of the involved signalling pathways and molecular targets. Mouse hippocampal neuronal HT22 cells were irradiated with acute gamma doses of 0.5 Gy, 1.0 Gy and 4.0 Gy. Changes in the cellular proteome were investigated by isotope-coded protein label technology and tandem mass spectrometry after 4 and 24 hours. To compare the findings with the in vivo response, male NMRI mice were irradiated on postnatal day 10 with a gamma dose of 1.0 Gy, followed by evaluation of the cellular proteome of hippocampus and cortex 24 hours post-irradiation. Analysis of the in vitro proteome showed that signalling pathways related to synaptic actin-remodelling were significantly affected at 1.0 Gy and 4.0 Gy but not at 0.5 Gy after 4 and 24 hours. We observed radiation-induced reduction of the miR-132 and Rac1 levels; miR-132 is known to regulate Rac1 activity by blocking the GTPase-activating protein p250GAP. In the irradiated hippocampus and cortex we observed alterations in the signalling pathways similar to those in vitro. The decreased expression of miR-132 and Rac1 was associated with an increase in hippocampal cofilin and phospho-cofilin. The Rac1-Cofilin pathway is involved in the modulation of synaptic actin filament formation that is necessary for correct spine and synapse morphology to enable processes of learning and memory. We suggest that acute radiation exposure leads to rapid dendritic spine and synapse morphology alterations via aberrant cytoskeletal signalling and processing and that this is associated with the immediate neurocognitive side effects observed in patients treated with ionising radiation. PMID:25329592

  13. Inter-comparison of safety culture within selected practices in Ghana utilising ionising radiation.

    PubMed

    Faanu, A; Schandorf, C; Darko, E O; Boadu, M; Emi-Reynolds, G; Awudu, A R; Gyekye, P K; Kpeglo, D O

    2010-12-01

    The safety culture of selected practices and facilities in Ghana utilising radiation sources or radiation emitting devices has been assessed using a performance indicator, which provided status information on management and operating staff commitment to safety. The questionnaire was based on the following broad areas: general safety considerations, safety policy at the facility level, safety practices at the facility level, definition of responsibility, staff training, safety of the physical structure of the facility and the emergency plans. The analysis showed that the percentage levels of commitment to safety for the respective practices are as follows: conventional radiography, 23.3-90.0%; research reactor, 73.3%; gamma irradiation facility, 53.3%; radiotherapy, 76.7%; X-ray scanner, 80.0%; gamma scanner, 76.7%; industrial radiography 86.7% and nuclear density practice, 78%. None of the practices or facilities was able to satisfy all the requirements that will ensure a 100% level of safety culture. PMID:20699247

  14. Mortality and ionising radiation exposures among workers employed at the Fernald Feed Materials Production Center (1951–1985)

    PubMed Central

    Silver, Sharon R; Bertke, Stephen J; Hein, Misty Jena; Daniels, Robert D; Fleming, Donald A; Anderson, Jeri L; Pinney, Susan M; Hornung, Richard W; Tseng, Chih-Yu

    2015-01-01

    Objectives To examine mortality patterns and dose-response relations between ionising radiation and mortality outcomes of a priori interest in 6409 uranium workers employed for at least 30 days (1951–1985), and followed through 2004. Methods Cohort mortality was evaluated through standardised mortality ratios (SMR). Linear excess relative risk (ERR) regression models examined associations between cause-specific mortality and exposures to internal ionising radiation from uranium deposition, external gamma and x-ray radiation, and radon decay products, while adjusting for non-radiologic covariates. Results Person-years at risk totalled 236 568 (mean follow-up 37 years), and 43% of the cohort had died. All-cause mortality was below expectation only in salaried workers. Cancer mortality was significantly elevated in hourly males, primarily from excess lung cancer (SMR=1.25, 95% CI 1.09 to 1.42). Cancer mortality in salaried males was near expectation, but lymphohaematopoietic malignancies were significantly elevated (SMR=1.52, 95% CI 1.06 to 2.12). A positive dose-response relation was observed for intestinal cancer, with a significant elevation in the highest internal organ dose category and a significant dose-response with organ dose from internal uranium deposition (ERR=1.5 per 100 µGy, 95% CI 0.12 to 4.1). Conclusions A healthy worker effect was observed only in salaried workers. Hourly workers had excess cancer mortality compared with the US population, although there was little evidence of a dose-response trend for any cancer evaluated except intestinal cancer. The association between non-malignant respiratory disease and radiation dose observed in previous studies was not apparent, possibly due to improved exposure assessment, different outcome groupings, and extended follow-up. PMID:23322915

  15. Thermoluminescent properties of Ni and Co doped synthetic, high pressure, high temperature diamonds: application to ionising radiation dosimetry.

    PubMed

    Benabdesselam, M; Iacconi, P; Gheeraert, E; Kanda, H; Lapraz, D; Briand, D

    2002-01-01

    An investigation of the thermoluminescence (TL) properties of high pressure, high temperature (HPHT) synthetic diamond crystals grown under diluted nickel or cobalt as solvent catalysts is reported. After a study of TL properties of 6 different samples, it is shown that a crystal grown with Ni+2%Ti and annealed at 2100 K presents an intense glow peak at around 490 K. This peak is characterised by a broad emission band centred at 530 nm (2.34 eV). This crystal presents a significant, reproducible and linear TL response relative to the absorbed dose up to an X ray air kerma of 10 Gy. All these features make this material suitable for ionising radiation dosimetry. A similar study is made on another crystal grown from pure Co, and a comparative review of the results does show that for dosimetry work, Ni-containing diamonds are more appropriate than those grown from Co catalyst. PMID:12382890

  16. Unrepairable DNA double-strand breaks that are generated by ionising radiation determine the fate of normal human cells.

    PubMed

    Noda, Asao; Hirai, Yuko; Hamasaki, Kanya; Mitani, Hiroshi; Nakamura, Nori; Kodama, Yoshiaki

    2012-11-15

    After an exposure to ionising radiation, cells can quickly repair damage to their genomes; however, a few unrepairable DNA double-strand breaks (DSBs) emerge in the nucleus in a prolonged culture and perpetuate as long as the culture continues. These DSBs may be retained forever in cells such as non-dividing ageing tissues, which are resistant to apoptosis. We show that such unrepairable DSBs, which had been advocated by the classical target theory as the 'radiation hit', could account for permanent growth arrest and premature senescence. The unrepairable DSBs build up with repeated irradiation, which accounts for an accumulated dose. Because these DSBs tend to be paired, we propose that the untethered and 'torn-off' molecular structures at the broken ends of the DNA result in an alteration of chromatin structure, which protects the ends of the DNA from genomic catastrophe. Such biochemical responses are important for cell survival but may cause gradual tissue malfunction, which could lead to the late effects of radiation exposure. Thus, understanding the biology of unrepairable damage will provide new insights into the long-term effects of radiation. PMID:22899723

  17. Population exposure to ionising radiation from CT examinations in Aosta Valley between 2001 and 2008

    PubMed Central

    Catuzzo, P; Aimonetto, S; Zenone, F; Fanelli, G; Marchisio, P; Meloni, T; Pasquino, M; Tofani, S

    2010-01-01

    Recent and continuous advances in CT, such as the development of multislice CT, have promoted a rapid increase in its clinical application. Today, CT accounts for approximately 10% of the total number of medical radiographic procedures worldwide. However, the growing performance of the new CT generations have increased not only the diagnostic opportunities, but also the radiation dose to the patient. The relative contribution to the collective radiation dose is now estimated to be approximately 50%. Several papers have been published concerning the intensive use of CT and its contribution to the collective dose. However, most of the literature concerns the years 1997–2003 and the dosimetric evaluations are generally limited to the main standard protocols (chest, head and abdomen), deriving the effective dose by the simple application of the diagnostic reference levels. Only specific dosimetric analyses of single and innovative procedures have been published recently. Moreover, few data comes from Italian radiology departments. This paper aims to bridge these gaps. Firstly, it characterises in terms of measured CT dose index (CTDI) two last-generation scanners of the Radiological Department of Aosta Hospital. Secondly, it evaluates the effective dose from most of the CT examinations performed from 2001 to 2008 to compare protocols and technologies in line with the suggestions of the 2007 Recommendations of the International Commission on Radiological Protection, Publication 103. Finally, it estimates the collective dose to the population. PMID:21088089

  18. Pre-service Teachers' Subject Knowledge of and Attitudes about Radioactivity and Ionising Radiation

    NASA Astrophysics Data System (ADS)

    Denys Colclough, Nicholas; Lock, Roger; Soares, Allan

    2011-02-01

    This study focussed on secondary school (11-18 years) pre-service teachers' (n = 73) knowledge of and attitudes towards risks associated with alpha, beta, and gamma radiations. A multi-method approach was used with physics, chemistry, biology, and history graduates undertaking the one-year initial teacher training, Post Graduate Certificate in Education course at a university in central England. A novel research tool, involving interviews about real concrete contexts and first-hand data collection with radioactive sources, was employed to gain insights into a sub-set of the sample (n = 12) of pre-service teachers' subject knowledge of and attitudes towards risk. The subject knowledge of all the pre-service teachers was also measured using a Certainty of Response Index instrument; multiple-choice questions with associated confidence indicators. Although the physicists displayed the higher levels of knowledge, they also demonstrated limitations in their knowledge and held misconceptions such as irradiation being confused with contamination. Physics graduates hold more rational attitudes and a greater willingness to accept risk while the attitudes of graduates in the other subject disciplines are more disparate. These findings raise questions about the extent to which pre-service science and history teachers have the knowledge necessary to teach this topic. The article concludes with discussion of the implications these findings have for initial teacher training, continuing professional development needs for teachers already in the profession, and curriculum developers.

  19. Considerations concerning the use of counting active personal dosimeters in pulsed fields of ionising radiation.

    PubMed

    Ambrosi, Peter; Borowski, Markus; Iwatschenko, Michael

    2010-06-01

    Active personal electronic dosimeters (APDs) exhibit limitations in pulsed radiation fields, which cannot be overcome without the use of new detection technology. As an interim solution, this paper proposes a method by which some conventional dosimeters can be operated in a way such that, based on the basic knowledge about the pulsed radiation field, any dosimetric failure of the dosimeter is signalised by the instrument itself. This method is not applicable to all combinations of APD and pulsed radiation field. The necessary requirements for the APD and for the parameters of the pulsed radiation field are given in the paper. Up to now, all such requirements for APDs have not been tested or verified in a type test. The suitability of the method is verified for the use of one APD used in two clinical pulsed fields. PMID:20083488

  20. Recombination processes in ionised plasmas

    NASA Astrophysics Data System (ADS)

    Bastin, Robert

    The observational analysis of astrophysical plasmas relies on accurate calculations of the atomic processes involved. The recombination spectra of singly ionised oxygen (O il) and carbon (C il) present excellent tools for investigating regions such as planetary nebulae and H II regions. In this thesis, detailed treatments of the recombination processes of both O II and C II are presented. Using the R-matrix solution to the close coupling equations, I present the results of accurate photoionisation calculations. Bound state energy levels are determined and oscillator strengths calculated for both species. Recombination coefficients were evalu ated for low n and 1, for C II in LS-coupling, and 0 II in intermediate coupling, taking particular care to treat resonances effectively. Sample photoionisation cross-sections are presented for both species, and compared to previous work. A complete radiative-cascade model is treated for both species, in order to determine line emissivities under nebular conditions at a wide range of temperatures and densities. Collisional effects are treated for C II, along with, for the first time, the effects of high temperature dielectronic recombination, allowing the modelling of regions of much higher electron temperature than previous work. The O II calculations were performed under intermediate coupling for the first time, allowing the effects of non-statistical popula tions of the parent ion fine-structure levels and dielectronic recombination onto bound states within this fine-structure to be taken into account in line emissivities. Detailed comparison with previous theoretical work was made for both species. The application of the C II and 0 n recombination spectra to determining tempera ture and densities from the observed spectra of a number of ionised nebulae is considered. The potential for using the new recombination spectra as diagnostic tools to solve some of the key problems in the study of ionised nebulae is demonstrated.

  1. Study of the uncertainty in estimation of the exposure of non-human biota to ionising radiation.

    PubMed

    Avila, R; Beresford, N A; Agüero, A; Broed, R; Brown, J; Iospje, M; Robles, B; Suañez, A

    2004-12-01

    Uncertainty in estimations of the exposure of non-human biota to ionising radiation may arise from a number of sources including values of the model parameters, empirical data, measurement errors and biases in the sampling. The significance of the overall uncertainty of an exposure assessment will depend on how the estimated dose compares with reference doses used for risk characterisation. In this paper, we present the results of a study of the uncertainty in estimation of the exposure of non-human biota using some of the models and parameters recommended in the FASSET methodology. The study was carried out for semi-natural terrestrial, agricultural and marine ecosystems, and for four radionuclides (137Cs, 239Pu, 129I and 237Np). The parameters of the radionuclide transfer models showed the highest sensitivity and contributed the most to the uncertainty in the predictions of doses to biota. The most important ones were related to the bioavailability and mobility of radionuclides in the environment, for example soil-to-plant transfer factors, the bioaccumulation factors for marine biota and the gut uptake fraction for terrestrial mammals. In contrast, the dose conversion coefficients showed low sensitivity and contributed little to the overall uncertainty. Radiobiological effectiveness contributed to the overall uncertainty of the dose estimations for alpha emitters although to a lesser degree than a number of transfer model parameters. PMID:15700701

  2. Pre-Service Teachers' Subject Knowledge of and Attitudes about Radioactivity and Ionising Radiation

    ERIC Educational Resources Information Center

    Colclough, Nicholas Denys; Lock, Roger; Soares, Allan

    2011-01-01

    This study focussed on secondary school (11-18 years) pre-service teachers' (n = 73) knowledge of and attitudes towards risks associated with alpha, beta, and gamma radiations. A multi-method approach was used with physics, chemistry, biology, and history graduates undertaking the one-year initial teacher training, Post Graduate Certificate in…

  3. A radiotelemetry pill for the measurement of ionising radiation using a mercuric iodide detector.

    PubMed

    Hassan, M A; Pearce, G; Edwards, J P

    1978-03-01

    A small radiation measuring pill is briefly described which utilises the principles of radiotelemetry and the properties of a room temperature semiconductor radiation detector such as mercuric iodide. By transmitting a radio signal to a remote receiver the pill could be an effective tool in localising bleeding sites along the gastrointestinal tract and also possibly in the diagnosis of gastrointestinal carcinoma. Other uses of the radiopill are suggested. The size of the pill is 27 mm x 10 mm diameter and consists of a mercuric iodide crystal, an amplifier, a frequency modulated transmitter and one battery. The radiotransmitter operates at about 106 MHz and has a range of about 10m, and the sensitivity of the pill has been found for 99Tcm, 131I and 32P. PMID:306112

  4. Non-fluoroscopic navigation systems for radiofrequency catheter ablation for supraventricular tachycardia reduce ionising radiation exposure

    PubMed Central

    See, Jason; Amora, Jonah L; Lee, Sheldon; Lim, Paul; Teo, Wee Siong; Tan, Boon Yew; Ho, Kah Leng; Lee, Chee Wan; Ching, Chi Keong

    2016-01-01

    INTRODUCTION The use of non-fluoroscopic systems (NFS) to guide radiofrequency catheter ablation (RFCA) for the treatment of supraventricular tachycardia (SVT) is associated with lower radiation exposure. This study aimed to determine if NFS reduces fluoroscopy time, radiation dose and procedure time. METHODS We prospectively enrolled patients undergoing RFCA for SVT. NFS included EnSite™ NavX™ or CARTO® mapping. We compared procedure and fluoroscopy times, and radiation exposure between NFS and conventional fluoroscopy (CF) cohorts. Procedural success, complications and one-year success rates were reported. RESULTS A total of 200 patients over 27 months were included and RFCA was guided by NFS for 79 patients; those with atrioventricular nodal reentrant tachycardia (AVNRT), left-sided atrioventricular reentrant tachycardia (AVRT) and right-sided AVRT were included (n = 101, 63 and 36, respectively). Fluoroscopy times were significantly lower with NFS than with CF (10.8 ± 11.1 minutes vs. 32.0 ± 27.5 minutes; p < 0.001). The mean fluoroscopic dose area product was also significantly reduced with NFS (NSF: 5,382 ± 5,768 mGy*cm2 vs. CF: 21,070 ± 23,311 mGy*cm2; p < 0.001); for all SVT subtypes. There was no significant reduction in procedure time, except for left-sided AVRT ablation (NFS: 79.2 minutes vs. CF: 116.4 minutes; p = 0.001). Procedural success rates were comparable (NFS: 97.5% vs. CF: 98.3%) and at one-year follow-up, there was no significant difference in the recurrence rates (NFS: 5.2% vs. CF: 4.2%). No clinically significant complications were observed in both groups. CONCLUSION The use of NFS for RFCA for SVT is safe, with significantly reduced radiation dose and fluoroscopy time. PMID:26805664

  5. Follow-up of children exposed to ionising radiation from cardiac catheterisation: the Coccinelle study

    PubMed Central

    Baysson, H.; Nkoumazok, B.; Barnaoui, S.; Réhel, J. L.; Girodon, B.; Milani, G.; Boudjemline, Y.; Bonnet, D.; Laurier, D.; Bernier, M. O.

    2015-01-01

    Cardiac catheterisation has become an essential tool in the diagnosis and treatment of children with a wide variety of congenital and acquired forms of cardiovascular disease. Despite the clear clinical benefit to the patient, radiation exposure from paediatric cardiac catheterisation procedures (CCPs) may be substantial. Given children's greater sensitivity to radiation and the longer life span during which radiation health effects can develop, an epidemiological cohort study, named Coccinelle or ‘Ladybird’ (French acronym for ‘Cohorte sur le risque de cancer après cardiologie interventionnelle pédiatrique’), is carried out in France to evaluate the risks of leukaemia and solid cancers in this population. A total number of 8000 included children are expected. Individual CCP-related doses will be assessed for each child included in the cohort. For each CCP performed, dosimetric parameters (dose–area product, fluoroscopy time and total number of cine frames) are retrieved retrospectively. Organ doses, especially to the lung, the oesophagus and the thyroid, are calculated with PCXMC software. The cohort will be followed up through linkage with French paediatric cancer registries. PMID:25833897

  6. Modelling chromosomal aberration induction by ionising radiation: The influence of interphase chromosome architecture

    NASA Astrophysics Data System (ADS)

    Ottolenghi, A.; Ballarini, F.; Biaggi, M.

    Several advances have been achieved in the knowledge of nuclear architecture and functions during the last decade, thus allowing the identification of interphase chromosome territories and sub-chromosomal domains (e.g. arm and band domains). This is an important step in the study of radiation-induced chromosome aberrations; indeed, the coupling between track-structure simulations and reliable descriptions of the geometrical properties of the target is one of the main tasks in modelling aberration induction by radiation, since it allows one to clarify the role of the initial positioning of two DNA lesions in determining their interaction probability. In the present paper, the main recent findings on nuclear and chromosomal architecture are summarised. A few examples of models based on different descriptions of interphase chromosome organisation (random-walk models, domain models and static models) are presented, focussing on how the approach adopted in modelling the target nuclei and chromosomes can influence the simulation of chromosomal aberration yields. Each model is discussed by taking into account available experimental data on chromosome aberration induction and/or interphase chromatin organisation. Preliminary results from a mechanistic model based on a coupling between radiation track-structure features and explicitly-modelled, non-overlapping chromosome territories are presented.

  7. Follow-up of children exposed to ionising radiation from cardiac catheterisation: the Coccinelle study.

    PubMed

    Baysson, H; Nkoumazok, B; Barnaoui, S; Réhel, J L; Girodon, B; Milani, G; Boudjemline, Y; Bonnet, D; Laurier, D; Bernier, M O

    2015-07-01

    Cardiac catheterisation has become an essential tool in the diagnosis and treatment of children with a wide variety of congenital and acquired forms of cardiovascular disease. Despite the clear clinical benefit to the patient, radiation exposure from paediatric cardiac catheterisation procedures (CCPs) may be substantial. Given children's greater sensitivity to radiation and the longer life span during which radiation health effects can develop, an epidemiological cohort study, named Coccinelle or 'Ladybird' (French acronym for 'Cohorte sur le risque de cancer après cardiologie interventionnelle pédiatrique'), is carried out in France to evaluate the risks of leukaemia and solid cancers in this population. A total number of 8000 included children are expected. Individual CCP-related doses will be assessed for each child included in the cohort. For each CCP performed, dosimetric parameters (dose-area product, fluoroscopy time and total number of cine frames) are retrieved retrospectively. Organ doses, especially to the lung, the oesophagus and the thyroid, are calculated with PCXMC software. The cohort will be followed up through linkage with French paediatric cancer registries. PMID:25833897

  8. Deterministic effect of lens at leukergy of patients who received low doses of ionising radiation.

    PubMed

    Yeltokova, M; Zharliganova, D; Shaidarov, M; Bakhtin, M; Kazymbet, P; Tel, L; Dossakhanov, A; Kozhakbayeva, M; Hoshi, M

    2015-09-01

    To explore the possibility to use the lens extract as an in vitro stimulator to conduct a test of stimulated leukergy in liquidators of the accident consequences (LAC) on Chernobyl Nuclear Power Plant (CNPP) with a cataract in the long-term period. The study sample included 72 men-LAC on CNPP, at the age from 42 to 65 y, who have a cataract. The comparison group consisted of 60 men, with a cataract, of the same age, and who were not exposed to radiation. The control group was composed of 60 men, at the age of 42-58 y without lens pathology. Phenomenon of the stimulated leukergy was revealed in persons who had been exposed to radiation in the dose of 18.2 ± 0.58 cGy and was observed in 5.7-8.05 % (P < 0.001), suggesting a continued high auto-aggression to the lens antigens, and the strength of cell-mediated immunity. PMID:25969524

  9. Genotoxicity Induced by Foetal and Infant Exposure to Magnetic Fields and Modulation of Ionising Radiation Effects

    PubMed Central

    Udroiu, Ion; Antoccia, Antonio; Tanzarella, Caterina; Giuliani, Livio; Pacchierotti, Francesca; Cordelli, Eugenia; Eleuteri, Patrizia; Villani, Paola; Sgura, Antonella

    2015-01-01

    Background Few studies have investigated the toxicity and genotoxicity of extremely low frequency magnetic fields (ELF-MF) during prenatal and neonatal development. These phases of life are characterized by cell proliferation and differentiation, which might make them sensitive to environmental stressors. Although in vitro evidences suggest that ELF-MF may modify the effects of ionizing radiation, no research has been conducted so far in vivo on the genotoxic effects of ELF-MF combined with X-rays. Aim and methods Aim of this study was to investigate in somatic and germ cells the effects of chronic ELF-MF exposure from mid gestation until weaning, and any possible modulation produced by ELF-MF exposure on ionizing radiation-induced damage. Mice were exposed to 50 Hz, 65 μT magnetic field, 24 hours/day, for a total of 30 days, starting from 12 days post-conception. Another group was irradiated with 1 Gy X-rays immediately before ELF-MF exposure, other groups were only X-irradiated or sham-exposed. Micronucleus test on blood erythrocytes was performed at multiple times from 1 to 140 days after birth. Additionally, 42 days after birth, genotoxic and cytotoxic effects on male germ cells were assessed by comet assay and flow cytometric analysis. Results ELF-MF exposure had no teratogenic effect and did not affect survival, growth and development. The micronucleus test indicated that ELF-MF induced a slight genotoxic damage only after the maximum exposure time and that this effect faded away in the months following the end of exposure. ELF-MF had no effects on ionizing radiation (IR)-induced genotoxicity in erythrocytes. Differently, ELF–MF appeared to modulate the response of male germ cells to X-rays with an impact on proliferation/differentiation processes. These results point to the importance of tissue specificity and development on the impact of ELF-MF on the early stages of life and indicate the need of further research on the molecular mechanisms underlying

  10. Protection against ionising radiation and synergism with thiols by zinc aspartate.

    PubMed

    Floersheim, G L; Floersheim, P

    1986-06-01

    Pre-treatment with zinc aspartate protected mice against the lethal effects of radiation and raised the LD50 from 8 Gy to 12.2 Gy. Zinc chloride and zinc sulphate were clearly less active. The radioprotective effect of zinc aspartate was equivalent to cysteamine and slightly inferior to S,2-aminoethylisothiourea (AET). Zinc aspartate displayed a similar therapeutic index to the thiols but could be applied at an earlier time before irradiation. Synergistic effects occurred with the combined administration of zinc aspartate and thiols. By giving zinc aspartate with cysteamine, the LD50 was increased to 13.25 Gy and, by combining it in the optimal protocol with AET, to 17.3 Gy. The radioprotection by zinc and its synergism with thiols is explained by the stabilisation of thiols through the formation of zinc complexes. PMID:3518853

  11. The long-term effects of acute exposure to ionising radiation on survival and fertility in Daphnia magna.

    PubMed

    Sarapultseva, Elena I; Dubrova, Yuri E

    2016-10-01

    The results of recent studies have provided strong evidence for the transgenerational effects of parental exposure to ionising radiation and chemical mutagens. However, the transgenerational effects of parental exposure on survival and fertility remain poorly understood. To establish whether parental irradiation can affect the survival and fertility of directly exposed organisms and their offspring, crustacean Daphnia magna were given 10, 100, 1000 and 10,000mGy of acute γ-rays. Exposure to 1000 and 10,000mGy significantly compromised the viability of irradiated Daphnia and their first-generation progeny, but did not affect the second-generation progeny. The fertility of F0 and F1Daphnia gradually declined with the dose of parental exposure and significantly decreased at dose of 100mGy and at higher doses. The effects of parental irradiation on the number of broods were only observed among the F0Daphnia exposed to 1000 and 10,000mGy, whereas the brood size was equally affected in the two consecutive generations. In contrast, the F2 total fertility was compromised only among progeny of parents that received the highest dose of 10,000mGy. We propose that the decreased fertility observed among the F2 progeny of parents exposed to 10,000mGy is attributed to transgenerational effects of parental irradiation. Our results also indicate a substantial recovery of the F2 progeny of irradiated F0Daphnia exposed to the lower doses of acute γ-rays. PMID:27288911

  12. Measurement of occupational doses of ionising radiation to the lens of the eyes of interventional radiologists.

    PubMed

    Higgins, Anthony

    2016-03-01

    Currently, there exists no standardised method for monitoring radiation doses to the eye lens. This investigation aimed to determine the optimum method for monitoring the eye doses for interventional radiologists. Three interventional radiologists were issued with a series of dosimeters to wear during their routine work. These dosimeters were worn at defined positions on the body and the absorbed dose to each position was measured. It was confirmed that the dose received to the thyroid collar followed an apparently well-defined relationship to the dose recorded on the forehead, which is representative of the dose to the lens of the eye. It was also confirmed that, as hypothesised, the dose to the left eye was universally greater than to the right, although by varying factors. It was concluded that the use of dosimeters attached to the inside arms of protective eyewear is the optimum solution for eye lens dosimetry. It was also concluded that, when used with a dose conversion factor which corroborates existing literature, dosimeters attached to the outside of a thyroid collar yield sufficiently accurate results for use in routine dosimetry programmes. PMID:26643204

  13. Determination of methemoglobin in human blood after ionising radiation by EPR

    NASA Astrophysics Data System (ADS)

    Polakovs, M.; Mironova-Ulmane, N.; Pavlenko, A.; Aboltins, A.

    2015-03-01

    In the present work presents results of investigations of radiation influence on blood of patients examined by radio-isotopes diagnosis (Tc99m), blood of Chernobyl clean-up workers and human blood irradiated by LINAC using Electron Paramagnetic Resonance (EPR). The EPR spectroscopy reveals information on electronic states of transition metal ions, particularly Fe3+ in different spin states. It is shown that EPR spectra of blood of patients before examination has signal from metal-protein transferrin (g=4.3) and after administration of radioisotope proves signal of Fe3+ (methemaglobin) in the high spin state (g=6.0). The EPR spectra of Chernobyl liquidator display number of signals including low and high state of ion Fe3+ (g = 2.0 and g=6.0), and transferrin (g=4.3). The EPR spectra of irradiated human blood by LINAC (linear accelerator) have only signal Fe3+ (methemaglobin) in low-spin state with g = 2.0.

  14. Chromosome instability of HPRT-mutant subclones induced by ionising radiation of various LET.

    PubMed

    Govorun, R D; Koshlan, I V; Koshlan, N A; Krasavin, E A; Shmakova, N L

    2002-01-01

    The induction of HPRT-mutations and survival of Chinese hamster cells (line B11ii-FAF28, clone 431) were studied after irradiation by 4He and 12C-ions of various LET (20-360 keV/micrometers), produced by the U-200 heavy ion accelerator. The RBE increases with LET up to the maximum at 100-200 keV/micrometers and then decreases. Cytogenetic analysis was performed on the HPRT-mutant subclones selected from unirradiated Chinese hamster V-79 cells and from HPRT-mutant subclones that arose after exposure to gamma-rays, 1 GeV protons and 14N-ions (LET-77 keV/micrometers), produced by the synchrophasotron and the U-400M heavy ion accelerator. Slow growing mutant subclones were observed. The cytogenetic properties of individual clones were highly heterogeneous and chromosome instability was observed in both spontaneous and radiation-induced mutants. Chromosome instability was highest among spontaneous mutants and decreased with increasing LET. PMID:12539752

  15. On the mechanism of populating 3p levels of neon under pumping by a hard ioniser

    SciTech Connect

    Khasenov, M U

    2011-03-31

    The effect of quenching additives on the luminescence properties of helium - neon mixtures under pumping by {alpha} particles emitted from {sup 210}Po atoms is considered. It is concluded that, under excitation by a heavy charged particle, the population of the 3p'[1/2]{sub 0} level of neon is not related to the dissociative recombination of molecular ions. It is suggested that the most likely channels for populating the 3p level are the excitation transfer from metastable helium atoms to neon atoms and direct excitation of neon by nuclear particles and secondary electrons. (lasers and active media)

  16. Risk of cancer from occupational exposure to ionising radiation: retrospective cohort study of workers in France, the United Kingdom, and the United States (INWORKS)

    PubMed Central

    Cardis, Elisabeth; Daniels, Robert D; Gillies, Michael; O’Hagan, Jacqueline A; Hamra, Ghassan B; Haylock, Richard; Laurier, Dominique; Leuraud, Klervi; Moissonnier, Monika; Schubauer-Berigan, Mary K; Thierry-Chef, Isabelle; Kesminiene, Ausrele

    2015-01-01

    Study question Is protracted exposure to low doses of ionising radiation associated with an increased risk of solid cancer? Methods In this cohort study, 308 297 workers in the nuclear industry from France, the United Kingdom, and the United States with detailed monitoring data for external exposure to ionising radiation were linked to death registries. Excess relative rate per Gy of radiation dose for mortality from cancer was estimated. Follow-up encompassed 8.2 million person years. Of 66 632 known deaths by the end of follow-up, 17 957 were due to solid cancers. Study answer and limitations Results suggest a linear increase in the rate of cancer with increasing radiation exposure. The average cumulative colon dose estimated among exposed workers was 20.9 mGy (median 4.1 mGy). The estimated rate of mortality from all cancers excluding leukaemia increased with cumulative dose by 48% per Gy (90% confidence interval 20% to 79%), lagged by 10 years. Similar associations were seen for mortality from all solid cancers (47% (18% to 79%)), and within each country. The estimated association over the dose range of 0-100 mGy was similar in magnitude to that obtained over the entire dose range but less precise. Smoking and occupational asbestos exposure are potential confounders; however, exclusion of deaths from lung cancer and pleural cancer did not affect the estimated association. Despite substantial efforts to characterise the performance of the radiation dosimeters used, the possibility of measurement error remains. What this study adds The study provides a direct estimate of the association between protracted low dose exposure to ionising radiation and solid cancer mortality. Although high dose rate exposures are thought to be more dangerous than low dose rate exposures, the risk per unit of radiation dose for cancer among radiation workers was similar to estimates derived from studies of Japanese atomic bomb survivors. Quantifying the cancer risks associated

  17. Ionising radiation and risk of death from leukaemia and lymphoma in radiation-monitored workers (INWORKS): an international cohort study

    PubMed Central

    Leuraud, Klervi; Richardson, David B; Cardis, Elisabeth; Daniels, Robert D; Gillies, Michael; O'Hagan, Jacqueline A; Hamra, Ghassan B; Haylock, Richard; Laurier, Dominique; Moissonnier, Monika; Schubauer-Berigan, Mary K; Thierry-Chef, Isabelle; Kesminiene, Ausrele

    2015-01-01

    Summary Background There is much uncertainty about the risks of leukaemia and lymphoma after repeated or protracted low-dose radiation exposure typical of occupational, environmental, and diagnostic medical settings. We quantified associations between protracted low-dose radiation exposures and leukaemia, lymphoma, and multiple myeloma mortality among radiation-monitored adults employed in France, the UK, and the USA. Methods We assembled a cohort of 308 297 radiation-monitored workers employed for at least 1 year by the Atomic Energy Commission, AREVA Nuclear Cycle, or the National Electricity Company in France, the Departments of Energy and Defence in the USA, and nuclear industry employers included in the National Registry for Radiation Workers in the UK. The cohort was followed up for a total of 8·22 million person-years. We ascertained deaths caused by leukaemia, lymphoma, and multiple myeloma. We used Poisson regression to quantify associations between estimated red bone marrow absorbed dose and leukaemia and lymphoma mortality. Findings Doses were accrued at very low rates (mean 1·1 mGy per year, SD 2·6). The excess relative risk of leukaemia mortality (excluding chronic lymphocytic leukaemia) was 2·96 per Gy (90% CI 1·17–5·21; lagged 2 years), most notably because of an association between radiation dose and mortality from chronic myeloid leukaemia (excess relative risk per Gy 10·45, 90% CI 4·48–19·65). Interpretation This study provides strong evidence of positive associations between protracted low-dose radiation exposure and leukaemia. Funding Centers for Disease Control and Prevention, Ministry of Health, Labour and Welfare of Japan, Institut de Radioprotection et de Sûreté Nucléaire, AREVA, Electricité de France, National Institute for Occupational Safety and Health, US Department of Energy, US Department of Health and Human Services, University of North Carolina, Public Health England. PMID:26436129

  18. Phytosanitation with Ionising Radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter by Neil Heather and Guy Hallman, in “Pest Management and Phytosanitary Trade Barriers,” CABI Press, covers ionizing irradiation phytosanitary treatments. Although irradiation as an idea and research object has as long a phytosanitary history an any other phytosanitary treatment, c...

  19. System-Level Radiation Hardening

    NASA Technical Reports Server (NTRS)

    Ladbury, Ray

    2014-01-01

    Although system-level radiation hardening can enable the use of high-performance components and enhance the capabilities of a spacecraft, hardening techniques can be costly and can compromise the very performance designers sought from the high-performance components. Moreover, such techniques often result in a complicated design, especially if several complex commercial microcircuits are used, each posing its own hardening challenges. The latter risk is particularly acute for Commercial-Off-The-Shelf components since high-performance parts (e.g. double-data-rate synchronous dynamic random access memories - DDR SDRAMs) may require other high-performance commercial parts (e.g. processors) to support their operation. For these reasons, it is essential that system-level radiation hardening be a coordinated effort, from setting requirements through testing up to and including validation.

  20. How do monomeric components of a polymer gel dosimeter respond to ionising radiation: A steady-state radiolysis towards preparation of a 3D polymer gel dosimeter

    NASA Astrophysics Data System (ADS)

    Kozicki, Marek

    2011-12-01

    Ionising radiation-induced reactions of aqueous single monomer solutions and mixtures of poly(ethylene glycol) diacrylate (PEGDA) and N, N'-methylenebisacrylamide (Bis) in a steady-state condition are presented below and above gelation doses in order to highlight reactions in irradiated 3D polymer gel dosimeters, which are assigned for radiotherapy dosimetry. Both monomers are shown to undergo radical polymerisation and cross-linking, which result in the measured increase in molecular weight and radius of gyration of the formed polydisperse polymer coils. The formation of nanogels was also observed for Bis solutions at a low concentration. In the case of PEGDA-Bis mixtures, co-polymerisation is suggested as well. At a sufficiently high radiation dose, the formation of a polymer network was observed for both monomers and their mixture. For this reason a sol-gel analysis for PEGDA and Bis was performed gravimetrically and a proposition of an alternative to this method employing a nuclear magnetic resonance technique is made. The two monomers were used for preparation of 3D polymer gel dosimeters having the acronyms PABIG and PABIG nx. The latter is presented for the first time in this work and is a type of the formerly established PABIG polymer gel dosimeter. The elementary characteristics of the new composition are presented, underlining the ease of its preparation, low dose threshold, and slightly increased sensitivity but lower quasi-linear range of dose response in comparison to PABIG.

  1. Co-mutation of histone H2AX S139A with Y142A rescues Y142A-induced ionising radiation sensitivity

    PubMed Central

    Brown, James A.L.; Eykelenboom, John K.; Lowndes, Noel F.

    2012-01-01

    Under normal conditions histone H2AX is constitutively phosphorylated on tyrosine (Y) 142 by Williams–Beuren syndrome transcription factor kinase (WSTF). Following DNA double strand breaks (DSB), Y142 is de-phosphorylated and serine (S) 139 is phosphorylated. Here we explored DSB-dependent cross talk between H2AX residues S139 and Y142. H2axY142A mutation resulted in increased sensitivity to ionising radiation (IR), compared to H2axS139A. Interestingly, co-mutation of S139A and Y142A rescued IR sensitivity. The DSB response proteins 53Bp1 and Rad51 were recruited to IR-induced foci (IRIF) in H2axS139A, H2axY142A and H2axS139A/Y142A cells. Our results suggest that H2axY142A IR sensitivity is dependent upon the C-terminal residue, S139. PMID:23772364

  2. A new approach to studying the effects of ionising radiation on single cells using FTIR synchrotron microspectroscopy

    NASA Astrophysics Data System (ADS)

    Lipiec, E.; Birarda, G.; Kowalska, J.; Lekki, J.; Vaccari, L.; Wiecheć, A.; Wood, B. R.; Kwiatek, W. M.

    2013-12-01

    The effect of ionizing radiation on single cells using a proton source was investigated using Fourier transform infrared (FTIR) microspectroscopy. The prostate cancer cells (DU-145) were irradiated by a specific number (50, 200, 400, 2000 and 4000) of protons per cell. Next after fixing the cells with 70% ethanol micro-FTIR spectra were obtained using both: (a) the synchrotron radiation source with a Mercury-Cadmium-Telluride (MCT) detector and (b) a globar source with a focal plane array (FPA) detector. FTIR spectra obtained from both instrumental configurations were analyzed independently to investigate the changes in the DNA phosphodiester region (1150-950 cm-1) of irradiated and control (untreated by ionizing radiation) cells. A Principal Component Analysis (PCA) scores plot revealed distinct clusters for all groups of irradiated cells, even for those irradiated by the smallest dose of protons. The dose-dependent changes in the relative intensities of DNA peak at 970 cm-1 (ribose-phosphate skeletal motions), along with a shift of the O-P-O band corresponding to the symmetric phosphodiester stretching mode at 1090 cm-1 were observed. The results demonstrate that FTIR spectroscopy is a promising tool to investigate DNA damage in single cells and may become an important tool in assessing cell damage following radiotherapy.

  3. An evaluation of the shielding effectiveness of lead aprons used in clinics for protection against ionising radiation from novel radioisotopes.

    PubMed

    Deb, Pradip; Jamison, Robert; Mong, Lisa; U, Paul

    2015-07-01

    The purpose of this study is to evaluate the effectiveness of personal radiation shields currently worn in hospital and other diagnostic environments. This study was performed with four different radioisotopes; (18)F, (99m)Tc, (124)I and (131)I. (18)F results showed a decrease in dose with 0.5-mm Pb shielding but the reduction provided does not warrant its use clinically. (124)I testing demonstrated that dose enhancement can occur in greater shield thicknesses. PET isotope (124)I can be adequately shielded using 0.25-mm Pb equivalent aprons but any higher thickness increase the wearer's dose. As a result more shielding does not always equal more protection. The (131)I test showed that no dose reduction occurred, even when tested with up to 1.25-mm Pb equivalent shielding. Novel radioisotopes being used in the laboratory and clinic should be individually tested as each requires specific shielding testing. PMID:25848112

  4. Deoxyribonucleic acid damage-associated biomarkers of ionising radiation: current status and future relevance for radiology and radiotherapy

    PubMed Central

    Rothkamm, K

    2013-01-01

    Diagnostic and therapeutic radiation technology has developed dramatically in recent years, and its use has increased significantly, bringing clinical benefit. The use of diagnostic radiology has become widespread in modern society, particularly in paediatrics where the clinical benefit needs to be balanced with the risk of leukaemia and brain cancer increasing after exposure to low doses of radiation. With improving long-term survival rates of radiotherapy patients and the ever-increasing use of diagnostic and interventional radiology procedures, concern has risen over the long-term risks and side effects from such treatments. Biomarker development in radiology and radiotherapy has progressed significantly in recent years to investigate the effects of such use and optimise treatment. Recent biomarker development has focused on improving the limitations of established techniques by the use of automation, increasing sensitivity and developing novel biomarkers capable of quicker results. The effect of low-dose exposure (0–100 mGy) used in radiology, which is increasingly linked to cancer incidences, is being investigated, as some recent research challenges the linear-no-threshold model. Radiotherapy biomarkers are focused on identifying radiosensitive patients, determining the treatment-associated risk and allowing for a tailored and more successful treatment of cancer patients. For biomarkers in any of these areas to be successfully developed, stringent criteria must be applied in techniques and analysis of data to reduce variation among reports and allow data sets to be accurately compared. Newly developed biomarkers can then be used in combination with the established techniques to better understand and quantify the individual biological response to exposures associated with radiology tests and to personalise treatment plans for patients. PMID:23659923

  5. Assessing the performance under ionising radiation of lead tungstate scintillators for EM calorimetry in the CLAS12 Forward Tagger

    NASA Astrophysics Data System (ADS)

    Fegan, S.; Auffray, E.; Battaglieri, M.; Buchanan, E.; Caiffi, B.; Celentano, A.; Colaneri, L.; D`Angelo, A.; De Vita, R.; Dormenev, V.; Fanchini, E.; Lanza, L.; Novotny, R. W.; Parodi, F.; Rizzo, A.; Sokhan, D.; Tarasov, I.; Zonta, I.

    2015-07-01

    The well-established technology of electromagnetic calorimetry using Lead Tungstate crystals has recently seen an upheaval, with the closure of one of the most experienced large-scale suppliers of such crystals, the Bogoroditsk Technical Chemical Plant (BTCP), which was instrumental in the development of mass production procedures for PWO-II, the current benchmark for this scintillator. Obtaining alternative supplies of Lead Tungstate crystals matching the demanding specifications of contemporary calorimeter devices now presents a significant challenge to detector research and development programmes. In this paper we describe a programme of assessment carried out for the selection, based upon the performance under irradiation, of Lead Tungstate crystals for use in the Forward Tagger device, part of the CLAS12 detector in Hall B at Jefferson Lab. The crystals tested were acquired from SICCAS, the Shanghai Institute of Ceramics, Chinese Academy of Sciences. The tests performed are intended to maximise the performance of the detector within the practicalities of the crystal manufacturing process. Results of light transmission, before and after gamma ray irradiation, are presented and used to calculate dk, the induced radiation absorption coefficient, at 420 nm, the peak of the Lead Tungstate emission spectrum. Results for the SICCAS crystals are compared with identical measurements carried out on Bogoroditsk samples, which were acquired for the Forward Tagger development program before the closure of the facility. Also presented are a series of tests performed to determine the feasibility of recovering radiation damage to the crystals using illumination from an LED, with such illumination available in the Forward Tagger from a light monitoring system integral to the detector.

  6. The level of serum ionised calcium, aspartate aminotransferase, insulin, glucose, betahydroxybutyrate concentrations and blood gas parameters in cows with left displacement of abomasum.

    PubMed

    Sen, I; Ok, M; Coskun, A

    2006-01-01

    The purpose of this study was to determine concentrations of serum glucose, aspartate aminotransferase (AST), insulin, beta-hydroxybutyrate (BOH) and ionised calcium (Ica) in dairy cows with left displaced abomasum (LDA) and to compare these parameters before and after surgical correction of LDA. Eighteen Swiss-Holstein dairy cows with LDA were used in this study. Clinically healthy post parturient cows (n: 10) from a local dairy farm were used as control group. Blood samples were collected from the jugular vein from all the cows. Surgery was performed in cows with LDA. Blood samples from cows with LDA were collected 24 hours after surgery. The abomasum was repositioned followed by an omentopexy. Six of the 18 cows with LDA had clinical ketosis as detected with urine dipstick. The mean concentrations of insulin, BOH, glucose and AST in cows with LDA at admission time were increased compared with the healthy cows. But the mean concentration of ICa at admission time was slightly decreased compared with healthy cows. The mean BOH concentration was decreased 24 hours following surgery compared with values on admission time. However, the mean serum AST levels were increased both at admission time and 24 hours after surgery compared with healthy cows. The levels of blood gas parameters in cows with LDA were not significantly different in comparison with healthy cows, although hyperbasemia in six of 18 cows with LDA was determined. In conclusion, the results of this study indicated that serum insulin, glucose, AST and BOH levels were increased in dairy cows with LDA. Serum BOH and ICa levels were decreased 24 hours after surgery compared with values on admission time. All cows with LDA used in this study had subclinical/clinical ketosis. We could say that ketosis might be a risk factor for the displacement of the abomasum. PMID:17203740

  7. The ionisation energy of cyclopentadienone: a photoelectron-photoion coincidence study

    NASA Astrophysics Data System (ADS)

    Ormond, Thomas K.; Hemberger, Patrick; Troy, Tyler P.; Ahmed, Musahid; Stanton, John F.; Ellison, G. Barney

    2015-08-01

    Imaging photoelectron photoion coincidence (iPEPICO) spectra of cyclopentadienone (C5H4=O and C5D4=O) have been measured at the Swiss Light Source Synchrotron (Paul Scherrer Institute, Villigen, Switzerland) at the Vacuum Ultraviolet (VUV) Beamline. Complementary to the photoelectron spectra, photoionisation efficiency curves were measured with tunable VUV radiation at the Chemical Dynamics Beamline at the Advanced Light Source Synchrotron (Lawrence Berkeley National Laboratory, Berkeley, CA, USA). For both experiments, molecular beams diluted in argon and helium were generated from the vacuum flash pyrolysis of o-phenylene sulphite in a resistively heated microtubular SiC flow reactor. The Franck-Condon profiles and ionisation energies were calculated at the CCSD(T) level of theory, and are in excellent agreement with the observed iPEPICO spectra. The ionisation energies of both cyclopentadienone-d0, IE(C5H4=O), and cyclopentadienone-d4, IE(C5D4=O), were observed to be the same: 9.41 ± 0.01 eV. The mass-selected threshold photoelectron spectrum (ms-TPES) of cyclopentadienone reveals that the C=C stretch in the ground state of the cation is excited upon ionisation, supporting computational evidence that the ground state of the cation is ? 2A2, and is in agreement with previous studies. However, the previously reported ionisation potential has been improved considerably in this work. In addition, since o-benzoquinone (o-O=C6H4=O and o-O=C6D4=O) is also produced in this process, its ms-TPES has been recorded. From the iPEPICO and photoionisation efficiency spectra, we infer an adiabatic ionisation energy of IE(o-O=C6H4=O) = 9.3 ± 0.1 eV, but the rather structureless spectrum indicates a strong change in geometry upon ionisation making this value less reliable.

  8. Concerns with low-level ionizing radiation

    SciTech Connect

    Yalow, R.S.

    1994-12-31

    Populations have been studied in geographic areas of increased natural radiation, in radiation-exposed workers, in patients medically exposed, and in accidental exposures. No reproducible evidence exists of harmful effects from increases in background radiation three to ten times the usual levels. There is no increase in leukemia or other cancers among American military participants in nuclear testing, no increase in leukemia or thyroid cancer among medical patients receiving {sup 131}I for diagnosis or treatment of hypothyroidism, and no increase in lung cancer among nonsmokers exposed to increased radon in the home. The association of radiation with the atomic bomb and with excessive regulatory and health physics as-low-as-reasonably-achievable (ALARA) radiation levels practices has created a climate of fear about the dangers of radiation at any level. However, there is no evidence that radiation exposures at the levels equivalent to medical usage are harmful. The unjustified excessive concern with radiation at any level, however, precludes beneficial uses of radiation and radioactivity in medicine, science, and industry.

  9. Outdoor radiofrequency radiation levels in the West Bank-Palestine.

    PubMed

    Lahham, Adnan; Hammash, Alaa

    2012-05-01

    This work presents the results of exposure levels to radio frequency (RF) emission from different sources in the environment of the West Bank-Palestine. These RF emitters include FM and TV broadcasting stations and mobile phone base stations. Power densities were measured at 65 locations distributed over the West Bank area. These locations include mainly centres of the major cities. Also a 24 h activity level was investigated for a mobile phone base station to determine the maximum activity level for this kind of RF emitters. All measurements were conducted at a height of 1.7 m above ground level using hand held Narda SRM 3000 spectrum analyzer with isotropic antenna capable of collecting RF signals in the frequency band from 75 MHz to 3 GHz. The average value of power density resulted from FM radio broadcasting in all investigated locations was 0.148 μW cm(-2), from TV broadcasting was 0.007 μW cm(-2) and from mobile phone base station was 0.089 μW cm(-2). The maximum total exposure evaluated at any location was 3.86 μW cm(-2). The corresponding exposure quotient calculated for this site was 0.02. This value is well below unity indicating compliance with the International Commission on non-ionising Radiation protection guidelines. Contributions from all relevant RF sources to the total exposure were evaluated and found to be ~62 % from FM radio, 3 % for TV broadcasting and 35 % from mobile phone base stations. The average total exposure from all investigated RF sources was 0.37 μW cm(-2). PMID:21835841

  10. Development of a RILIS ionisation scheme for gold at ISOLDE, CERN

    NASA Astrophysics Data System (ADS)

    Marsh, B. A.; Fedosseev, V. N.; Kosuri, P.

    2006-07-01

    At the ISOLDE on-line isotope separation facility, the resonance ionisation laser ion source (RILIS) can be used to ionise reaction products as they effuse from the target. The RILIS process of laser step-wise resonance ionisation of atoms in a hot metal cavity provides a highly element selective stage in the preparation of the radioactive ion beam. As a result, the ISOLDE mass separators can provide beams of a chosen isotope with greatly reduced isobaric contamination. With the addition of a new three-step ionisation scheme for gold, the RILIS is now capable of ionising 26 of the elements. The optimal scheme was determined during an extensive study of the atomic energy levels and auto-ionising states of gold, carried out by means of in-source resonance ionisation spectroscopy. Details of the ionisation scheme and a summary of the spectroscopy study are presented.

  11. Development of a RILIS ionisation scheme for gold at ISOLDE, CERN

    NASA Astrophysics Data System (ADS)

    Marsh, B. A.; Fedosseev, V. N.; Kosuri, P.

    At the ISOLDE on-line isotope separation facility, the resonance ionisation laser ion source (RILIS) can be used to ionise reaction products as they effuse from the target. The RILIS process of laser step-wise resonance ionisation of atoms in a hot metal cavity provides a highly element selective stage in the preparation of the radioactive ion beam. As a result, the ISOLDE mass separators can provide beams of a chosen isotope with greatly reduced isobaric contamination. With the addition of a new three-step ionisation scheme for gold, the RILIS is now capable of ionising 26 of the elements. The optimal scheme was determined during an extensive study of the atomic energy levels and auto-ionising states of gold, carried out by means of in-source resonance ionisation spectroscopy. Details of the ionisation scheme and a summary of the spectroscopy study are presented.

  12. Determination of structure parameters in molecular tunnelling ionisation model

    NASA Astrophysics Data System (ADS)

    Wang, Jun-Ping; Zhao, Song-Feng; Zhang, Cai-Rong; Li, Wei; Zhou, Xiao-Xin

    2014-04-01

    We extracted the accurate structure parameters in a molecular tunnelling ionisation model (the so-called MO-ADK model) for 23 selected linear molecules including some inner orbitals. The molecular wave functions with the correct asymptotic behaviour are obtained by solving the time-independent Schrödinger equation with B-spline functions and molecular potentials numerically constructed using the modified Leeuwen-Baerends (LBα) model. We show that the orientation-dependent ionisation rate reflects the shape of the ionising orbitals in general. The influences of the Stark shifts of the energy levels on the orientation-dependent ionisation rates of the polar molecules are studied. We also examine the angle-dependent ionisation rates (or probabilities) based on the MO-ADK model by comparing with the molecular strong-field approximation calculations and with recent experimental measurements.

  13. Assessment of RF radiation levels in the vicinity of 60 GSM mobile phone base stations in Iran.

    PubMed

    Nayyeri, Vahid; Hashemi, Seyed Mohammad; Borna, Maryam; Jalilian, Hamid-Reza; Soleimani, Mohammad

    2013-07-01

    Increasing development of mobile communication infrastructure while enhancing availability of the technology raises concerns among the public, who see more cell towers erected each day, about possible health effects of electromagnetic radiations. Thereon, a survey of radio-frequency radiation from 60 GSM base stations was carried out in Tehran, Iran at several places mostly located in major medical and educational centres. Measurements were performed at 15 locations near each base station site, i.e. 900 locations in total. Since there are other RF radiation sources such as broadcasting services whose carrier frequencies are <3 GHz, the whole band of 27 MHz to 3 GHz has been assessed for hazardous exposures as well. The results were compared with the relevant guideline of International Commission on Non-Ionising Radiation Protection and that of Iran, confirming radiation exposure levels being satisfactorily below defined limits and non-detrimental. PMID:23222504

  14. Ultraviolet radiation levels during the Antarctic spring

    NASA Technical Reports Server (NTRS)

    Frederick, John E.; Snell, Hilary E.

    1988-01-01

    The decrease in atmospheric ozone over Antarctica during spring implies enhanced levels of ultraviolet (UV) radiation received at the earth's surface. Model calculations show that UV irradiances encountered during the occurrence of an Antarctic 'ozone hole' remain less than those typical of a summer solstice at low to middle latitudes. However, the low ozone amounts observed in October 1987 imply biologically effective irradiances for McMurdo Station, Antarctica, that are comparable to or greater than those for the same location at December solstice. Life indigenous to Antarctica thereby experiences a greatly extended period of summerlike UV radiation levels.

  15. Background compensation for a radiation level monitor

    DOEpatents

    Keefe, D.J.

    1975-12-01

    Background compensation in a device such as a hand and foot monitor is provided by digital means using a scaler. With no radiation level test initiated, a scaler is down-counted from zero according to the background measured. With a radiation level test initiated, the scaler is up-counted from the previous down-count position according to the radiation emitted from the monitored object and an alarm is generated if, with the scaler having crossed zero in the positive going direction, a particular number is exceeded in a specific time period after initiation of the test. If the test is initiated while the scale is down-counting, the background count from the previous down- count stored in a memory is used as the initial starting point for the up-count.

  16. Vital parameters related low level laser radiation

    NASA Astrophysics Data System (ADS)

    Palmieri, Beniamino; Capone, Stefania

    2011-08-01

    The first work hypotesis is that biosensors on the patient detecting heart, breath rate and skin parameters, modulate laser radiation to enhance the therapeutic outcome; in the second work hypotesis: biofeedback could be effective, when integrated in the low level laser energy release.

  17. Strong ionisation in carbon nanowires

    NASA Astrophysics Data System (ADS)

    Kaymak, V.; Pukhov, A.; Shlyaptsev, V. N.; Rocca, J. J.

    2016-04-01

    Surfaces covered with nanostructures, such as nanowire arrays, are shown to facilitate a significantly higher absorption of laser energy as compared to flat surfaces. Due to the efficient coupling of the laser energy, highly energetic electrons are produced, which in turn can emit intense ultrafast X-ray pulses. Full three dimensional PIC simulations are used to analyse the behaviour of arrays of carbon nanowires 400 nm in diameter, irradiated by a 400-nm laser pulse of 60-fs duration at FWHM and a vector potential of α0 = 18. We analyse the ionisation dynamics of the nanowires. The difference of the ionisation strength and structure between linearly and circularly polarised laser beam is investigated. The nanowires are found to be fully ionised after about 30 laser cycles. Circularly polarised light reveals a slightly stronger ionisation effect.

  18. Theoretical investigation of the ultrafast dissociation of ionised biomolecules immersed in water: direct and indirect effects.

    PubMed

    Gaigeot, M-P; Lopez-Tarifa, P; Martin, F; Alcami, M; Vuilleumier, R; Tavernelli, I; Hervé du Penhoat, M-A; Politis, M-F

    2010-01-01

    Theoretical simulations are particularly well suited to investigate, at a molecular level, direct and indirect effects of ionising radiations in DNA, as in the particular case of irradiation by swift heavy ions such as those used in hadron therapy. In the past recent years, we have developed the modeling at the microscopic level of the early stages of the Coulomb explosion of DNA molecules immersed in liquid water that follows the irradiation by swift heavy ions. To that end, Time-Dependent Density Functional Theory molecular dynamics simulations (TD-DFT MD) have been developed where localised Wannier orbitals are propagated. This latter enables to separate molecular orbitals of each water molecule from the molecular orbitals of the biomolecule. Our main objective is to demonstrate that the double ionisation of one molecule of the liquid sample, either one water molecule from the solvent or the biomolecule, may be in some cases responsible for the formation of an atomic oxygen as a direct consequence of the molecule Coulomb explosion. Our hypothesis is that the molecular double ionisation arising from irradiation by swift heavy ions (about 10% of ionisation events by ions whose velocity is about the third of speed of light), as a primary event, though maybe less probable than other events resulting from the electronic cascading (for instance, electronic excitations, electron attachments), may be systematically more damageable (and more lethal), as supported by experiments that have been carried out in our group in the 1990s (in studies of damages created by K holes in DNA). The chemical reactivity of the produced atomic oxygen with other radicals present in the medium will ultimately lead to chemical products that are harmful to DNA. In the present paper, we review our theoretical methodology in an attempt that the community be familiar with our new approach. Results on the production of atomic oxygen as a result of the double ionisation of water or as a result of

  19. Defining reference levels for intra-operative radiation exposure in orthopaedic trauma: A retrospective multicentre study.

    PubMed

    Hardman, J; Elvey, M; Shah, N; Simson, N; Patel, S; Anakwe, R

    2015-12-01

    There is currently limited data to define reference levels for the use of ionising radiation in orthopaedic trauma surgery. In this multicentre study, we utilise methodology employed by the Health Protection Agency in establishing reference levels for diagnostic investigations in order to define analogous levels for common and reproducible orthopaedic trauma procedures. Four hundred ninety-five procedures were identified across four Greater London hospitals over a 1-year period. Exposure was defined in terms of both time and dose area product (DAP). Third quartile mean values for either parameter were used to define reference levels. Variations both between centres and grades of lead surgeon were analysed as secondary outcomes. Reference levels; dynamic hip screw (DHS) 1.9225000 Gycm(2)/70.50 s, intramedullary (IM) femoral nail 1.5837500 Gycm(2)/126.00 s, open reduction internal fixation (ORIF) clavicle 0.2042500 Gycm(2)/21.50 s, ORIF lateral malleolus 0.32250500 Gycm(2)/35.00 s, ORIF distal radius 0.1300000 Gycm(2)/56.00 s. Grade of surgeon did not influence exposure in dynamic hip screw, and was inversely related to exposure in intramedullary femoral nails. Less variation was observed with exposure time than with DAP. This study provides the most comprehensive reference to guide fluoroscopy use in orthopaedic trauma to date, and is of value both at the point of delivery and for audit of local practice. PMID:26604035

  20. Beam size measurement at high radiation levels

    SciTech Connect

    Decker, F.J.

    1991-05-01

    At the end of the Stanford Linear Accelerator the high energy electron and positron beams are quite small. Beam sizes below 100 {mu}m ({sigma}) as well as the transverse distribution, especially tails, have to be determined. Fluorescent screens observed by TV cameras provide a quick two-dimensional picture, which can be analyzed by digitization. For running the SLAC Linear Collider (SLC) with low backgrounds at the interaction point, collimators are installed at the end of the linac. This causes a high radiation level so that the nearby cameras die within two weeks and so-called radiation hard'' cameras within two months. Therefore an optical system has been built, which guides a 5 mm wide picture with a resolution of about 30 {mu}m over a distance of 12 m to an accessible region. The overall resolution is limited by the screen thickness, optical diffraction and the line resolution of the camera. Vibration, chromatic effects or air fluctuations play a much less important role. The pictures are colored to get fast information about the beam current, size and tails. Beside the emittance, more information about the tail size and betatron phase is obtained by using four screens. This will help to develop tail compensation schemes to decrease the emittance growth in the linac at high currents. 4 refs., 2 figs.

  1. Portable radiation monitor assures cleanup levels

    SciTech Connect

    Hasbach, A.

    1995-10-01

    Sevenson Environmental Services, Niagara Falls, NY, is a contractor at the EPA Superfund site at Montclair, NJ. Working with the Army Corps of Engineers, they are cleaning up radium waste left by a watch factory from the early 1900s. With the hazards of radium unknown at the time, radium in its many forms was spread throughout the region. As sand, it was used for concrete, as ash for packing material, and sometimes as landfill. When a hazardous site is found, Sevenson excavates the contaminated material and replaces it with clean fill. A Reuter-Stokes RSS-112 portable gamma monitoring system is used to ensure radiation is at sample background levels. Using a pressurized ionization chamber (PIC), the RSS-112 measures exposure rates from background to serious alarm levels over a wide energy range. Measurement takes place every five seconds. The portable system is 50% lighter than its predecessor and includes 300 point data storage, graphic display panel, 120-hour battery life between recharges, and RS-232 interface for downloading to a PC.

  2. Supersonic molecular beam-hyperthermal surface ionisation coupled with time-of-flight mass spectrometry applied to trace level detection of polynuclear aromatic hydrocarbons in drinking water for reduced sample preparation and analysis time.

    PubMed

    Davis, S C; Makarov, A A; Hughes, J D

    1999-01-01

    Analysis of sub-ppb levels of polynuclear aromatic hydrocarbons (PAHs) in drinking water by high performance liquid chromatography (HPLC) fluorescence detection typically requires large water samples and lengthy extraction procedures. The detection itself, although selective, does not give compound identity confirmation. Benchtop gas chromatography/mass spectrometry (GC/MS) systems operating in the more sensitive selected ion monitoring (SIM) acquisition mode discard spectral information and, when operating in scanning mode, are less sensitive and scan too slowly. The selectivity of hyperthermal surface ionisation (HSI), the high column flow rate capacity of the supersonic molecular beam (SMB) GC/MS interface, and the high acquisition rate of time-of-flight (TOF) mass analysis, are combined here to facilitate a rapid, specific and sensitive technique for the analysis of trace levels of PAHs in water. This work reports the advantages gained by using the GC/HSI-TOF system over the HPLC fluorescence method, and discusses in some detail the nature of the instrumentation used. PMID:10097402

  3. Epidemiological studies of Fukushima residents exposed to ionising radiation from the Fukushima Daiichi Nuclear Power Plant prefecture--a preliminary review of current plans.

    PubMed

    Akiba, Suminori

    2012-03-01

    It is now more than six months since the beginning of the accident on 11 March 2011 at the Fukushima Daiichi Nuclear Power Plant in Japan. The Japanese government and local health authorities have started to collect the information necessary to estimate radiation doses received by those living in the area around the plant, drafted plans for the health care of residents, and started to implement some of them. This paper reviews and discusses the studies necessary for risk evaluation of cancer and non-cancer diseases, including those already planned, mainly from the view point of evaluating health risk using epidemiological approaches. In the long run, it is important to establish a cohort with a control group. Even if the cumulative doses are estimated to be so low that it is difficult to evaluate the risk of cancer and non-cancer diseases, it is necessary to conduct such a study to reassure residents. The health care programme of the Fukushima Prefecture government, including health check-ups of residents, will help to assess indirect effects of radiation exposure, including psychological problems. The success of any studies of radiation epidemiology depends on the collection of accurate information on radiation doses received by the study subjects. However, some of the dosimetry surveys were not conducted in a timely manner. (It should be recognised, though, that such a problem might have been inevitable, considering the chaotic condition after the nuclear accident.) Accurate estimation of the radiation dose received by each resident is not only important for scientific risk evaluation but also to inform each resident about his or her potential risk. Otherwise, residents will bear an undue psychological burden from uncertainties regarding their radiation exposure and its health consequences. One of other important tasks in Fukushima is the improvement of the quality of the regional cancer registry in this prefecture. It is also important to start thyroid cancer

  4. Analysis of intact bacteria using rapid evaporative ionisation mass spectrometry.

    PubMed

    Strittmatter, Nicole; Jones, Emrys A; Veselkov, Kirill A; Rebec, Monica; Bundy, Jacob G; Takats, Zoltan

    2013-07-14

    An identification system for microorganisms based on recently developed rapid evaporative ionisation mass spectrometry (REIMS) is presented. Nine bacterial species cultured on various growth media were correctly identified to family-, genus-, and species-level based on their different mass spectral fingerprints using a cross-validated maximum margin criterion model. PMID:23736664

  5. Characterisation of ship diesel primary particulate matter at the molecular level by means of ultra-high-resolution mass spectrometry coupled to laser desorption ionisation--comparison of feed fuel, filter extracts and direct particle measurements.

    PubMed

    Rüger, Christopher P; Sklorz, Martin; Schwemer, Theo; Zimmermann, Ralf

    2015-08-01

    In this study, positive-mode laser desorption-ionisation ultra-high-resolution mass spectrometry (LDI-FT-ICR-MS) was applied to study combustion aerosol samples obtained from a ship diesel engine as well as the feed fuel, used to operate the engine. Furthermore, particulate matter was sampled from the exhaust tube using an impactor and analysed directly from the impaction foil without sample treatment. From the high percentage of shared sum formula as well as similarities in the chemical spread of aerosol and heavy fuel oil, results indicate that the primary aerosol mainly consists of survived, unburned species from the feed fuel. The effect of pyrosynthesis could be observed and was slightly more pronounced for the CH-class compared to other compound classes, but in summary not dominant. Alkylation pattern as well as the aromaticity distribution, using the double bond equivalent, revealed a shift towards lower alkylation state for the aerosol. The alkylation pattern of the most dominant series revealed a higher correlation between different aerosol samples than between aerosol and feed samples. This was confirmed by cluster analysis. Overall, this study shows that LDI-FT-ICR-MS can be successfully applied for the analysis of combustion aerosol at the molecular level and that sum formula information can be used to identify chemical differences between aerosol and fuel as well as between different size fractions of the particulate matter. PMID:25585886

  6. Monitoring radiation belt particle precipitation - automatic detection of enhanced transient ionisation in the lower plasmasphere using subionospheric narrow band VLF signals

    NASA Astrophysics Data System (ADS)

    Steinbach, P.; Lichtenberger, J.; Ferencz, Cs.

    2009-04-01

    Signals of naval VLF transmitters, propagating long distances along the Earth-ionosphere waveguide (EIWG) have been widely applied as effective tools for monitoring transient ionization at mesospheric altitudes. Perturbations in recorded amplitude and/or phase data series of stable frequency signals may refer to the effect of transient enhanced ionization in the EIWG, due to e.g. loss-cone precipitation of trapped energetic electrons (Carpenter et al., 1984, Dowden and Adams, 1990), burst of solar plasma particles (Clilverd et al., 2001). The contribution of precipitating particles are thought to be substantial in certain Sun-to-Earth energy flow processes in the upper atmosphere (Rodger et al., 2005). Narrow band VLF measuring network has been set up, developed and operated in Hungary, running in the last decade almost continuously, dedicated to monitor ionization enhancement regions along numerous transmitter-receiver paths. This setup is based on Omnipal and Ultra-MSK equipment, logging amplitude and phase data of received signals, sampled at frequencies of selected VLF transmitters. Signal trajectories, selected for recording represent proper configuration to survey transient ionization caused by energetic particles in the sub-polar region, such as effect of scattered particles of the inner radiation belt. Reprocessing of the mass archived recordings has been started using a newly developed signal processing code, detecting and classifying different sort of perturbations automatically on narrow band VLF series. Occurrence rates, daily and seasonal variation, statistics of transient ionization enhancements, their geographic distribution within the surveyed range and time period, and correlation with intense geomagnetic and/or Solar event is yielded by this analysis. References: Carpenter, D.L., Inan, U.S., Trimpi, M.L., Helliwell, R.A., and Katsufrakis, J.P.: Perturbations of subionospheric LF and MF signals due to whistler-induced electron precipitation burst

  7. Galactic cosmic ray radiation levels in spacecraft on interplanetary missions

    NASA Technical Reports Server (NTRS)

    Shinn, J. L.; Nealy, J. E.; Townsend, L. W.; Wilson, J. W.; Wood, J.S.

    1994-01-01

    Using the Langley Research Center Galactic Cosmic Ray (GCR) transport computer code (HZETRN) and the Computerized Anatomical Man (CAM) model, crew radiation levels inside manned spacecraft on interplanetary missions are estimated. These radiation-level estimates include particle fluxes, LET (Linear Energy Transfer) spectra, absorbed dose, and dose equivalent within various organs of interest in GCR protection studies. Changes in these radiation levels resulting from the use of various different types of shield materials are presented.

  8. Galactic cosmic ray radiation levels in spacecraft on interplanetary missions.

    PubMed

    Shinn, J L; Nealy, J E; Townsend, L W; Wilson, J W; Wood, J S

    1994-01-01

    Using the Langley Research Center galactic cosmic ray (GCR) transport computer code (HZETRN) and the computerized anatomical man (CAM) model, crew radiation levels inside manned spacecraft on interplanetary missions are estimated. These radiation-level estimates include particle fluxes, LET (linear energy transfer) spectra, absorbed dose, and dose equivalent within various organs of interest in GCR protection studies. Changes in these radiation levels resulting from the use of various different types of shield materials are presented. PMID:11538037

  9. Modelling of ground-level UV radiation

    NASA Astrophysics Data System (ADS)

    Koepke, P.; Schwander, H.; Thomalla, E.

    1996-06-01

    A number of modifications were made on the STAR radiation transmission model for greater ease of use while keeping its fault liability low. The improvements concern the entire aerosol description function of the model, the option of radiation calculation for different receiver geometries, the option of switching off temperature-dependent ozone absorption, and simplications of the STAR menu. The assets of using STAR are documented in the studies on the accuracy of the radiation transmission model. One of these studies gives a detailed comparison of the present model with a simple radiation model which reveals the limitations of approximation models. The other examines the error margin of radiation transmission models as a function of the input parameters available. It was found here that errors can be expected to range between 5 and 15% depending on the quality of the input data sets. A comparative study on the values obtained by measurement and through the model proved this judgement correct, the relative errors lying within the predicted range. Attached to this final report is a comprehensive sensitivity study which quantifies the action of various atmospheric parameters relevant to UV radiation, thus contributing to an elucidation of the process.

  10. Ionisation Equilibrium for the Non-Maxwellian Electron n-Distributions in Solar Flares: Updated Calculations

    NASA Astrophysics Data System (ADS)

    Dzifčáková, Elena; Dudík, Jaroslav

    2015-12-01

    We use the latest available atomic data to calculate the ionisation and recombination rates for the non-Maxwellian n-distributions, which were shown previously to provide a good fit to the enhanced intensities of dielectronic satellite lines during solar flares. The ionisation and recombination coefficients are subsequently used to derive the ionisation equilibrium. To do so, we consider odd values of n ranging from 1 to 19, i.e., from Maxwellian to strongly non-Maxwellian cases. These calculations involve all elements with proton number up to 30, i.e., H to Zn. The n-distributions modify both the ionisation and the recombination rates. The ionisation rates decrease more steeply at lower pseudo-temperatures, while the radiative recombination rate is reduced due to a lower number of low-energy electrons. The peaks of the dielectronic recombination rates become narrower. These changes are reflected in the ionisation equilibrium. Ion abundance peaks become narrower and can also be shifted, mostly towards higher temperatures. The He-like ions are an important exception, as they are formed in a larger temperature range than that for the Maxwellian distribution. The ions Si xiii - xiv used previously for the diagnostics of the n-distributions are affected only weakly, confirming the determination of n. The ionisation equilibria are available as the electronic supplementary material in a format compatible with the CHIANTI database.

  11. Responses to the low-level-radiation controversy

    SciTech Connect

    Bond, V.P.

    1981-10-07

    Some data sets dealing with the hazards of low-level radiation are discussed. It is concluded that none of these reports, individually or collectively, changes appreciably or even significantly the evaluations of possible low-level radiation effects that have been made by several authoritative national and international groups. (ACR)

  12. Experimental investigation of ionisation track structure of carbon ions at HIL Warsaw.

    PubMed

    Bantsar, A; Hilgers, G; Pszona, S; Rabus, H; Szeflinski, Z

    2015-09-01

    In view of the upcoming radiation therapy with carbon ions, the ionisation structure of the carbon ion track at the nanometre scale is of particular interest. Two different nanodosimeters capable of measuring track structure of ionising particles in a gas target equivalent to a nanometric site in condensed matter were involved in the presented experimental investigation, namely the NCBJ Jet Counter and the PTB Ion Counter. At the accelerator facility of the HIL in Warsaw, simulated nanometric volumes were irradiated with carbon ions of 45 and 76 MeV of kinetic energy, corresponding to a range in the tissue of ∼85 µm and ∼190 µm, respectively. The filling gas of both nanodosimeters' ionisation volume was molecular nitrogen N2, and the ionisation cluster size distributions, i.e. the statistical distribution of the number of ionizations produced by one single primary carbon ion in the filling gas, were measured for the two primary particle energies. PMID:25897141

  13. Ionisation of C60: is it temperature dependent?

    NASA Astrophysics Data System (ADS)

    Baba, M. Sai; Narasimhan, T. S. Lakshmi; Balasubramanian, R.; Mathews, C. K.

    1994-01-01

    In a recent paper, Drewello [T. Drewello, W. Kratschmer, M. Fieber-Erdmann and A. Ding, Int. J. Mass Spectrom. Ion Processes, 124 (1993) R1] reported a temperature dependent ionisation cross section for the formation of C2+60 in their photoionisation dynamic studies on C60 using synchrotron radiation. To check this, the ratio of ion intensities of C2+60 to that of C60 was determined as a function of temperature of C60 samples using a Knudsen effusion mass spectrometer. Our results indicate the absence of any temperature dependence of cross section for the formation of C2+60 in the temperature range of measurement (600-800 K) using electron impact ionisation.

  14. Physical models implemented in the GEANT4-DNA extension of the GEANT-4 toolkit for calculating initial radiation damage at the molecular level.

    PubMed

    Villagrasa, C; Francis, Z; Incerti, S

    2011-02-01

    The ROSIRIS project aims to study the radiobiology of integrated systems for medical treatment optimisation using ionising radiations and evaluate the associated risk. In the framework of this project, one research focus is the interpretation of the initial radio-induced damage in DNA created by ionising radiation (and detected by γ-H2AX foci analysis) from the track structure of the incident particles. In order to calculate the track structure of ionising particles at a nanometric level, the Geant4 Monte Carlo toolkit was used. Geant4 (Object Oriented Programming Architecture in C++) offers a common platform, available free to all users and relatively easy to use. Nevertheless, the current low-energy threshold for electromagnetic processes in GEANT4 is set to 1 keV (250 eV using the Livermore processes), which is an unsuitable value for nanometric applications. To lower this energy threshold, the necessary interaction processes and models were identified, and the corresponding available cross sections collected from the literature. They are mostly based on the plane-wave Born approximation (first Born approximation, or FBA) for inelastic interactions and on semi-empirical models for energies where the FBA fails (at low energies). In this paper, the extensions that have been introduced into the 9.3 release of the Geant4 toolkit are described, the so-called Geant4-DNA extension, including a set of processes and models adapted in this study and permitting the simulation of electron (8 eV-1 MeV), proton (100 eV-100 MeV) and alpha particle (1 keV-10 MeV) interactions in liquid water. PMID:21186212

  15. Radiation levels on empty cylinders containing heel material

    SciTech Connect

    Shockley, C.W.

    1991-12-31

    Empty UF{sub 6} cylinders containing heel material were found to emit radiation levels in excess of 200 mr/hr, the maximum amount stated in ORO-651. The radiation levels were as high as 335 mr/hr for thick wall (48X and 48Y) cylinders and 1050 mr/hr for thin wall (48G and 48H) cylinders. The high readings were found only on the bottom of the cylinders. These radiation levels exceeded the maximum levels established in DOT 49 CFR, Part 173.441 for shipment of cylinders. Holding periods of four weeks for thick-wall cylinders and ten weeks for thin-wall cylinders were established to allow the radiation levels to decay prior to shipment.

  16. Radiation levels in the SSC interaction regions

    SciTech Connect

    Groom, D.E.

    1988-06-10

    The radiation environment in a typical SSC detector has been evaluated using the best available particle production models coupled with Monte Carlo simulations of hadronic and electromagnetic cascades. The problems studied include direct charged particle dose, dose inside a calorimeter from the cascades produced by incident photons and hadrons, the flux of neutrons and photons backscattered from the calorimeter into a central cavity, and neutron flux in the calorimeter. The luminosity lifetime at the SSC is dominated by collision losses in the interaction regions, where the luminosity is equivalent to losing an entire full-energy proton beam into the apparatus every six days. The result of an average p-p collision can be described quite simply. The mean charged multiplicity is about 110, and the particles are distributed nearly uniformly in pseudorapidity ({eta}) over all the angles of interest. The transverse momentum distribution is independent of angle, and for our purposes may be written as p{perpendicular}exp(-p{perpendicular}/{beta}). The mean value of p{perpendicular} may be as high as 0.6 GeV/c. Most of the radiation is produced by the very abundant low-p{perpendicular} particles. The dose or neutron fluence produced by individual particles in this energy region are simulated over a wide variety of conditions, and several measurements serve to confirm the simulation results. In general, the response (a dose, fluence, the number of backscattered neutrons, etc.) for an incident particle of momentum p can be parameterized in the form Np{sup {alpha}}, where 0.5 < {alpha}< 1.0. The authors believe most of their results to be accurate to within a factor of two or three, sufficiently precise to serve as the basis for detailed designs.

  17. Ionised outflows in z ~ 2.4 quasar host galaxies

    NASA Astrophysics Data System (ADS)

    Carniani, S.; Marconi, A.; Maiolino, R.; Balmaverde, B.; Brusa, M.; Cano-Díaz, M.; Cicone, C.; Comastri, A.; Cresci, G.; Fiore, F.; Feruglio, C.; La Franca, F.; Mainieri, V.; Mannucci, F.; Nagao, T.; Netzer, H.; Piconcelli, E.; Risaliti, G.; Schneider, R.; Shemmer, O.

    2015-08-01

    Aims: Outflows driven by active galactic nuclei (AGN) are invoked by galaxy evolutionary models to quench star formation and to explain the origin of the relations observed locally between super-massive black holes and their host galaxies. We here aim to detect extended ionised outflows in luminous quasars, where we expect the highest activity both in star formation and in black-hole accretion. Currently, there are only a few studies based on spatially resolved observations of outflows at high redshift, z > 2. Methods: We analysed a sample of six luminous (L > 1047 erg/s) quasars at z ~ 2.4, observed in H-band using the near-IR integral field spectrometer SINFONI at the VLT. We performed a kinematic analysis of the [Oiii] emission line at λ = 5007 Å. Results: We detect fast, spatially extended outflows in five out of six targets. [Oiii]λ5007 has a complex gas kinematic, with blue-shifted velocities of a few hundreds of km s-1 and line widths up to 1500 km s-1. Using the spectroastrometric method, we infer a size of the ionised outflows of up to ~2 kpc. The properties of the ionised outflows, mass outflow rate, momentum rate, and kinetic power, are correlated with the AGN luminosity. The increase in outflow rate with increasing AGN luminosity is consistent with the idea that a luminous AGN pushes away the surrounding gas through fast outflows that are driven by radiation pressure, which depends on the emitted luminosity. Conclusions: We derive mass outflow rates of about 6-700 M⊙ yr-1 for our sample, which are lower than those observed in molecular outflows. The physical properties of ionised outflows show dependences on AGN luminosity that are similar to those of molecular outflows, but indicate that the mass of ionised gas is lower than that of molecular outflows. Alternatively, this discrepancy between ionised and molecular outflows could be explained with different acceleration mechanisms. Based on Observations collected at the European Organisation for

  18. Effects of low levels of radiation on humans

    SciTech Connect

    Auxier, J.A.

    1981-01-01

    The state of knowledge on effects of low-level ionizing radiations on humans is reviewed. Several problems relating to dose thresholds or lack of thresholds for several types of cancer and high LET radiations and the effects of fractionation and dose protection are discussed. (ACR)

  19. A VLT VIMOS IFU study of the ionisation nebula surrounding the supersoft X-ray source CAL 83

    NASA Astrophysics Data System (ADS)

    Gruyters, P.; Exter, K.; Roberts, T. P.; Rappaport, S.

    2012-08-01

    fit in with model predictions; in fact none of the models is able to fit the observed spectrum very well. Conclusions: The spectral line images of the region surrounding CAL 83 are revealing and instructive. However, more work on modelling the spectrum of the ionised gas is necessary, and especially for the high-ionisation level emission from CAL 83. In particular, we wish to know if the He ii emission and the other nebular lines are powered by the same ionising source.

  20. Effects of high vs low-level radiation exposure

    SciTech Connect

    Bond, V.P.

    1983-01-01

    In order to appreciate adequately the various possible effects of radiation, particularly from high-level vs low-level radiation exposure (HLRE, vs LLRE), it is necessary to understand the substantial differences between (a) exposure as used in exposure-incidence curves, which are always initially linear and without threshold, and (b) dose as used in dose-response curves, which always have a threshold, above which the function is curvilinear with increasing slope. The differences are discussed first in terms of generally familiar nonradiation situations involving dose vs exposure, and then specifically in terms of exposure to radiation, vs a dose of radiation. Examples are given of relevant biomedical findings illustrating that, while dose can be used with HLRE, it is inappropriate and misleading the LLRE where exposure is the conceptually correct measure of the amount of radiation involved.

  1. Biophysical modelling of early and delayed radiation damage at chromosome level

    NASA Astrophysics Data System (ADS)

    Andreev, S.; Eidelman, Y.

    Exposure by ionising radiation increases cancer risk in human population Cancer is thought to originate from an altered expression of certain number of specific genes It is now widely recognised that chromosome aberrations CA are involved in stable change in expression of genes by gain or loss of their functions Thus CA can contribute to initiation or progression of cancer Therefore understanding mechanisms of CA formation in the course of cancer development might be valuable tool for quantification and prognosis of different stages of radiation carcinogenesis Early CA are defined as aberrations induced in first post-irradiation mitotic cycle The present work describes the original biophysical technique for early CA modelling It includes the following simulation steps the ionising particle track structure the structural organisation of all chromosomes in G 0 G 1 cell nucleus spatial distribution of radiation induced DNA double-strand breaks dsb within chromosomes dsb rejoining and misrejoining modelling cell cycle taking into account mitotic delay which results in complex time dependence of aberrant cells in first mitosis The results on prediction of dose-response curves for simple and complex CA measured in cells undergoing first division cycle are presented in comparison with recent experimental data There is increasing evidence that CA are also observed in descendents of irradiated cells many generations after direct DNA damage These delayed CA or chromosome instability CI are thought to be a manifestation of genome

  2. Basic radiation protection training for nurses and paramedical personnel: Belgian experience and future perspectives.

    PubMed

    Clarijs, T; Coeck, M; Van Bladel, Lodewijk; Fremout, An

    2015-07-01

    When using ionising radiation for medical diagnosis or treatment of patients, understanding of relevant radiation protection principles and issues is indispensable. In Belgium, nurses and paramedical staff are required to acquire knowledge for protecting the patient against the detrimental effects of ionising radiation by means of a vocational training course. The experience with and challenges for this training course are presented here from a lecturer's point of view, together with a proposal for a future approach that harmonises the training content, its level and quality, according to European recommended standards. PMID:25821209

  3. Characterizing dose response relationships: Chronic gamma radiation in Lemna minor induces oxidative stress and altered polyploidy level.

    PubMed

    Van Hoeck, Arne; Horemans, Nele; Van Hees, May; Nauts, Robin; Knapen, Dries; Vandenhove, Hildegarde; Blust, Ronny

    2015-12-01

    The biological effects and interactions of different radiation types in plants are still far from understood. Among different radiation types, external gamma radiation treatments have been mostly studied to assess the biological impact of radiation toxicity in organisms. Upon exposure of plants to gamma radiation, ionisation events can cause, either directly or indirectly, severe biological damage to DNA and other biomolecules. However, the biological responses and oxidative stress related mechanisms under chronic radiation conditions are poorly understood in plant systems. In the following study, it was questioned if the Lemna minor growth inhibition test is a suitable approach to also assess the radiotoxicity of this freshwater plant. Therefore, L. minor plants were continuously exposed for seven days to 12 different dose rate levels covering almost six orders of magnitude starting from 80 μGy h(-1) up to 1.5 Gy h(-1). Subsequently, growth, antioxidative defence system and genomic responses of L. minor plants were evaluated. Although L. minor plants could survive the exposure treatment at environmental relevant exposure conditions, higher dose rate levels induced dose dependent growth inhibitions starting from approximately 27 mGy h(-1). A ten-percentage growth inhibition of frond area Effective Dose Rate (EDR10) was estimated at 95 ± 7 mGy h(-1), followed by 153 ± 13 mGy h(-1) and 169 ± 12 mGy h(-1) on fresh weight and frond number, respectively. Up to a dose rate of approximately 5 mGy h(-1), antioxidative enzymes and metabolites remained unaffected in plants. A significant change in catalase enzyme activity was found at 27 mGy h(-1) which was accompanied with significant increases of other antioxidative enzyme activities and shifts in ascorbate and glutathione content at higher dose rate levels, indicating an increase in oxidative stress in plants. Recent plant research hypothesized that environmental genotoxic stress conditions

  4. Predicted levels of human radiation tolerance extrapolated from clinical studies of radiation effects

    NASA Technical Reports Server (NTRS)

    Lushbaugh, C. C.

    1972-01-01

    Results of clinical studies of radiation effects on man are used to evaluate space radiation hazards encountered during manned space travel. Considered are effects of photons as well as of mixed fission neutrons and gamma irradiations in establishing body radiosensitivity and tolerance levels. Upper and lower dose-response-time relations for acute radiation syndromes in patients indicate that man is more than sufficiently radioresistant to make the risks of an early radiation effect during one short space mission intangibly small in relation to the other nonradiation risks involved.

  5. Radiation levels around the Fermilab Main Injector extraction septa

    SciTech Connect

    Bhat, C.M.; Mokhov, N.V.

    1997-05-01

    The Fermilab Main Injector extraction system will be capable of delivering a uniform 120 GeV beam of {approx} 3 x 10{sup 13} protons per spill to the fixed target experiments ( with spill time of 1 sec). Up to 2% of the beam is expected to be lost at the extraction septum and the Lambertson magnet. As a result, one expects increased radiation levels around the septa compared to other parts of the Main Injector. Realistic Monte-Carlo simulations have been performed to estimate the instantaneous and residual radiation levels in the beam extraction region. The results of these studies are presented and implications are discussed.

  6. Commentary on the Appropriate Radiation Level for Evacuations1

    PubMed Central

    Cuttler, Jerry M.

    2012-01-01

    This commentary reviews the international radiation protection policy that resulted in the evacuation of more than 90,000 residents from areas near the Fukushima Daiichi NPS and the enormous expenditures to protect them against a hypothetical risk of cancer. The basis for the precautionary measures is shown to be invalid; the radiation level chosen for evacuation is not conservative. The actions caused unnecessary fear and suffering. An appropriate level for evacuation is recommended. Radical changes to the ICRP recommendations are long overdue. PMID:23304099

  7. Energy levels and radiative transition rates for Ba XLVIII

    NASA Astrophysics Data System (ADS)

    Khatri, Indu; Goyal, Arun; Aggarwal, Sunny; Singh, A. K.; Mohan, Man

    2016-01-01

    Energy levels and radiative rates are reported for transitions in F-like Ba XLVIII. Configuration interaction has been included among 27 configurations (generating 431 levels) over a wide energy range up to 618 Rydbergs, and the fully relativistic multi-configurational Dirac-Fock method adopted for the calculations. To assess the accuracy, calculations have also been performed with the flexible atomic code, FAC. Radiative rates, oscillator strengths and line strengths are reported for all electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions from the lowest 3 levels, although calculations have been performed for a much larger number of levels. We have made comparisons of our results with existing available results and a good agreement has been achieved. Additionally, lifetimes for all 431 levels are listed.

  8. Lung cancer in relation to airborne radiation levels

    SciTech Connect

    Helsing, K.J.; Natta, P.V.; Comstock, G.W. ); Kalin, Heidi ) Chee, E. )

    1992-01-01

    A 1986 aeroradiometric survey of the eastern two-thirds of Washington County, Maryland provided and opportunity to study lung cancers in relation to gamma radiation levels. In the first approach, lung cancer deaths between 1963 and 1975 in four areas of the county categorized as low, moderately low, moderately high, and high showed relative risks of 1.00, 0.93, 1.01, and 1.43, respectively, after adjustment of sex, age, and smoking. A second approach used lung cancer cases diagnosed between 1975 and 1989, controls matched to cases by race, sex, and age, and aerometric radiation readings above the individual residences. In four levels of increasing gamma radiation, odds ratios adjusted for smoking were 1.00, 0.84, 0.90, and 0.92, respectively. No differences were statistically significant.

  9. The effects of radiative transfer on low-level cyclogenesis

    SciTech Connect

    Leach, M.J.; Raman, S.

    1995-04-01

    Many investigators have documented the role that thermodynamic forcing due to radiative flux divergence plays in the enhancement or generation of circulation. Most of these studies involve large-scale systems, small-scale systems such as thunderstorms, and squall lines. The generation of circulation on large scales results from the creation of divergence in the upper troposphere and the maintenance of low-level potentially unstable air, and the maintenance of baroclinicity throughout the atmosphere. On smaller scales, radiative flux divergence acts similarly. In the thunderstorms and squall lines, the radiative forcing acts as a pump, increasing the divergence at the top of the storm systems and increasing the updraft velocity and the intensity of inflow at mid-levels in the storm systems. Other researchers have examined the role of surface processes and low-level baroclinicity in east coast cyclogenesis. In this paper, we examine the interactive role that radiative flux divergence, clouds, and surface processes play in low-level cyclogenesis and the creation or maintenance of the boundary layer baroclinicity.

  10. No evidence for large-scale outflows in the extended ionised halo of ULIRG Mrk273

    NASA Astrophysics Data System (ADS)

    Spence, R. A. W.; Zaurín, J. Rodríguez; Tadhunter, C. N.; Rose, M.; Cabrera-Lavers, A.; Spoon, H.; Muñoz-Tuñón, C.

    2016-03-01

    We present deep new GTC/OSIRIS narrow-band images and optical WHT/ISIS long-slit spectroscopy of the merging system Mrk273 that show a spectacular extended halo of warm ionised gas out to a radius of ˜45 kpc from the system nucleus. Outside of the immediate nuclear regions (r > 6 kpc), there is no evidence for kinematic disturbance in the ionised gas: in the extended regions covered by our spectroscopic slits the emission lines are relatively narrow (FWHM ≲ 350 kms^{-1}) and velocity shifts small (|ΔV| ≲250 kms^{-1}). This is despite the presence of powerful near-nuclear outflows (FWHM > 1000 kms^{-1}; |ΔV| > 400 kms^{-1}; r < 6 kpc). Diagnostic ratio plots are fully consistent with Seyfert 2 photo-ionisation to the NE of the nuclear region, however to the SW the plots are more consistent with low-velocity radiative shock models. The kinematics of the ionised gas, combined with the fact that the main structures are aligned with low-surface-brightness tidal continuum features, are consistent with the idea that the ionised halo represents tidal debris left over from a possible triple-merger event, rather than a reservoir of outflowing gas.

  11. Ionisation as indicator for cosmic ray acceleration

    NASA Astrophysics Data System (ADS)

    Schuppan, F.; Röken, C.; Fedrau, N.; Becker Tjus, J.

    2014-06-01

    Astrospheres and wind bubbles of massive stars are believed to be sources of cosmic rays with energies E ≲ 1 TeV. These particles are not directly detectable, but their impact on surrounding matter, in particular ionisation of atomic and molecular hydrogen, can lead to observable signatures. A correlation study of both gamma ray emission, induced by proton-proton interactions of cosmic ray protons with kinetic energies Ep ≥ 280 MeV with ambient hydrogen, and ionisation induced by cosmic ray protons of kinetic energies Ep < 280 MeV can be performed in order to study potential sources of (sub)TeV cosmic rays.

  12. Health effects of low level radiation: carcinogenesis, teratogenesis, and mutagenesis

    SciTech Connect

    Ritenour, E.R.

    1986-04-01

    The carcinogenic effects of radiation have been demonstrated at high dose levels. At low dose levels, such as those encountered in medical diagnosis, the magnitude of the effect is more difficult to quantify. Three reasons for this difficulty are (1) the effects in human populations are small compared with the natural incidence of cancer in the populations; (2) it is difficult to transfer results obtained in animal studies to the human experience; and (3) the effects of latency period and plateau increase the complexity of population studies. In spite of these difficulties, epidemiologic studies of human populations exposed to low levels of radiation still play a valuable role in the determination of radiation carcinogenecity. They serve to provide upper estimates of risk and to rule out the appearance of new effects that may be masked by the effects of high doses. While there is evidence for mutagenic effects of radiation in experimental animals, no conclusive human data exist at the present. It is not possible to rule out the presence of genetic effects of radiation in humans, however, because many problems exist with regard to the epidemiologic detection of small effects when the natural incidence is relatively large. In animals, subtle effects (eg, a decrease in the probability of survival from egg to adult) may occur with greater frequency than more dramatic disorders in irradiated populations. However, these types of genetic abnormalities are difficult to quantitate. Current risk estimates are based primarily upon data pertaining to dominant mutations in rodents. Some specific locus studies also permit identification of recessive mutation rates. The embryo and fetus are considered to be at greater risk for adverse effects of radiation than is the adult.

  13. Gastrointestinal radiation injury: Prevention and treatment

    PubMed Central

    Shadad, Abobakr K; Sullivan, Frank J; Martin, Joseph D; Egan, Laurence J

    2013-01-01

    With the recent advances in detection and treatment of cancer, there is an increasing emphasis on the efficacy and safety aspects of cancer therapy. Radiation therapy is a common treatment for a wide variety of cancers, either alone or in combination with other treatments. Ionising radiation injury to the gastrointestinal tract is a frequent side effect of radiation therapy and a considerable proportion of patients suffer acute or chronic gastrointestinal symptoms as a result. These side effects often cause morbidity and may in some cases lower the efficacy of radiotherapy treatment. Radiation injury to the gastrointestinal tract can be minimised by either of two strategies: technical strategies which aim to physically shift radiation dose away from the normal intestinal tissues, and biological strategies which aim to modulate the normal tissue response to ionising radiation or to increase its resistance to it. Although considerable improvement in the safety of radiotherapy treatment has been achieved through the use of modern optimised planning and delivery techniques, biological techniques may offer additional further promise. Different agents have been used to prevent or minimize the severity of gastrointestinal injury induced by ionising radiation exposure, including biological, chemical and pharmacological agents. In this review we aim to discuss various technical strategies to prevent gastrointestinal injury during cancer radiotherapy, examine the different therapeutic options for acute and chronic gastrointestinal radiation injury and outline some examples of research directions and considerations for prevention at a pre-clinical level. PMID:23345942

  14. Radiation efficiency of earthquake sources at different hierarchical levels

    SciTech Connect

    Kocharyan, G. G.

    2015-10-27

    Such factors as earthquake size and its mechanism define common trends in alteration of radiation efficiency. The macroscopic parameter that controls the efficiency of a seismic source is stiffness of fault or fracture. The regularities of this parameter alteration with scale define several hierarchical levels, within which earthquake characteristics obey different laws. Small variations of physical and mechanical properties of the fault principal slip zone can lead to dramatic differences both in the amplitude of released stress and in the amount of radiated energy.

  15. Melatonin protection from chronic, low-level ionizing radiation.

    PubMed

    Reiter, Russel J; Korkmaz, Ahmet; Ma, Shuran; Rosales-Corral, Sergio; Tan, Dun-Xian

    2011-12-15

    In the current survey, we summarize the published literature which supports the use of melatonin, an endogenously produced molecule, as a protective agent against chronic, low-level ionizing radiation. Under in vitro conditions, melatonin uniformly was found to protect cellular DNA and plasmid super coiled DNA from ionizing radiation damage due to Cs(137) or X-radiation exposure. Likewise, in an in vivo/in vitro study in which humans were given melatonin orally and then their blood lymphocytes were collected and exposed to Cs(137) ionizing radiation, nuclear DNA from the cells of those individuals who consumed melatonin (and had elevated blood levels) was less damaged than that from control individuals. In in vivo studies as well, melatonin given to animals prevented DNA and lipid damage (including limiting membrane rigidity) and reduced the percentage of animals that died when they had been exposed to Cs(137) or Co(60) radiation. Melatonin's ability to protect macromolecules from the damage inflicted by ionizing radiation likely stems from its high efficacy as a direct free radical scavenger and possibly also due to its ability to stimulate antioxidative enzymes. Melatonin is readily absorbed when taken orally or via any other route. Melatonin's ease of self administration and its virtual absence of toxicity or side effects, even when consumed over very long periods of time, are essential when large populations are exposed to lingering radioactive contamination such as occurs as a result of an inadvertent nuclear accident, an intentional nuclear explosion or the detonation of a radiological dispersion device, i.e., a "dirty" bomb. PMID:22185900

  16. Elevated blood lead levels from exposure via a radiator workshop

    SciTech Connect

    Treble, R.G.; Thompson, T.S.; Morton, D.N.

    1998-04-01

    Elevated lead levels were discovered in blood samples collected from family members where both the father and the mother worked in a radiator repair workshop. The father and mother were found to have blood lead levels of 2.0 and 0.5 {micro}mol/L, respectively. The father`s blood lead level was just below the Canadian occupational health and safety intervention level. The two children had blood lead levels of 1.0 and 0.8 {micro}mol/L, both of which are in excess of the recommended guideline for intervention in the case of children. The exposure of the two children was possibly due to a combination of pathways including exposure at the workshop itself during visits and also the transportation of lead-containing dust to the home environment.

  17. EDDIX--a database of ionisation double differential cross sections.

    PubMed

    MacGibbon, J H; Emerson, S; Liamsuwan, T; Nikjoo, H

    2011-02-01

    The use of Monte Carlo track structure is a choice method in biophysical modelling and calculations. To precisely model 3D and 4D tracks, the cross section for the ionisation by an incoming ion, double differential in the outgoing electron energy and angle, is required. However, the double differential cross section cannot be theoretically modelled over the full range of parameters. To address this issue, a database of all available experimental data has been constructed. Currently, the database of Experimental Double Differential Ionisation Cross sections (EDDIX) contains over 1200 digitalised experimentally measured datasets from the 1960s to present date, covering all available ion species (hydrogen to uranium) and all available target species. Double differential cross sections are also presented with the aid of an eight parameter functions fitted to the cross sections. The parameters include projectile species and charge, target nuclear charge and atomic mass, projectile atomic mass and energy, electron energy and deflection angle. It is planned to freely distribute EDDIX and make it available to the radiation research community for use in the analytical and numerical modelling of track structure. PMID:21113060

  18. Cosmic ray induced ionisation of a molecular cloud shocked by the W28 supernova remnant

    NASA Astrophysics Data System (ADS)

    Vaupré, S.; Hily-Blant, P.; Ceccarelli, C.; Dubus, G.; Gabici, S.; Montmerle, T.

    2014-08-01

    Cosmic rays are an essential ingredient in the evolution of the interstellar medium, as they dominate the ionisation of the dense molecular gas, where stars and planets form. However, since they are efficiently scattered by the galactic magnetic fields, many questions remain open, such as where exactly they are accelerated, what is their original energy spectrum, and how they propagate into molecular clouds. In this work we present new observations and discuss in detail a method that allows us to measure the cosmic ray ionisation rate towards the molecular clouds close to the W28 supernova remnant. To perform these measurements, we use CO, HCO+, and DCO+ millimetre line observations and compare them with the predictions of radiative transfer and chemical models away from thermodynamical equilibrium. The CO observations allow us to constrain the density, temperature, and column density towards each observed position, while the DCO+/HCO+ abundance ratios provide us with constraints on the electron fraction and, consequently, on the cosmic ray ionisation rate. Towards positions located close to the supernova remnant, we find cosmic ray ionisation rates much larger (≳100) than those in standard galactic clouds. Conversely, towards one position situated at a larger distance, we derive a standard cosmic ray ionisation rate. Overall, these observations support the hypothesis that the γ rays observed in the region have a hadronic origin. In addition, based on CR diffusion estimates, we find that the ionisation of the gas is likely due to 0.1-1 GeV cosmic rays. Finally, these observations are also in agreement with the global picture of cosmic ray diffusion, in which the low-energy tail of the cosmic ray population diffuses at smaller distances than the high-energy counterpart.

  19. Radiative Lifetimes for High Levels of Neutral Fe

    NASA Astrophysics Data System (ADS)

    Lawler, James E.; Den Hartog, E.; Guzman, A.

    2013-01-01

    New radiative lifetime measurements for ~ 50 high lying levels of Fe I are reported. Laboratory astrophysics faces a challenge to provide basic spectroscopic data, especially reliable atomic transition probabilities, in the IR region for abundance studies. The availability of HgCdTe (HAWAII) detector arrays has opened IR spectral regions for extensive new spectroscopic studies. The SDSS III APOGEE project in the H-Band is an important example which will penetrate the dust obscuring the Galactic bulge. APOGEE will survey elemental abundances of 100,000 red giant stars in the bulge, bar, disk, and halo of the Milky Way. Many stellar spectra in the H-Band are, as expected, dominated by transitions of Fe I. Most of these IR transitions connect high levels of Fe. Our program has started an effort to meet this challenge with new radiative lifetime measurements on high lying levels of Fe I using time resolved laser induced fluorescence (TRLIF). The TRLIF method is typically accurate to 5% and is efficient. Our goal is to combine these accurate, absolute radiative lifetimes with emission branching fractions [1] to determine log(gf) values of the highest quality for Fe I lines in the UV, visible, and IR. This method was used very successfully by O’Brian et al. [2] on lower levels of Fe I. This method is still the best available for all but very simple spectra for which ab-initio theory is more accurate. Supported by NSF grant AST-0907732. [1] Branching fractions are being measured by M. Ruffoni and J. C. Pickering at Imperial College London. [2] O'Brian, T. R., Wickliffe, M. E., Lawler, J. E., Whaling, W., & Brault, J. W. 1991, J. Opt. Soc. Am. B 8, 1185

  20. Levels of naturally occurring gamma radiation measured in British homes and their prediction in particular residences.

    PubMed

    Kendall, G M; Wakeford, R; Athanson, M; Vincent, T J; Carter, E J; McColl, N P; Little, M P

    2016-03-01

    Gamma radiation from natural sources (including directly ionising cosmic rays) is an important component of background radiation. In the present paper, indoor measurements of naturally occurring gamma rays that were undertaken as part of the UK Childhood Cancer Study are summarised, and it is shown that these are broadly compatible with an earlier UK National Survey. The distribution of indoor gamma-ray dose rates in Great Britain is approximately normal with mean 96 nGy/h and standard deviation 23 nGy/h. Directly ionising cosmic rays contribute about one-third of the total. The expanded dataset allows a more detailed description than previously of indoor gamma-ray exposures and in particular their geographical variation. Various strategies for predicting indoor natural background gamma-ray dose rates were explored. In the first of these, a geostatistical model was fitted, which assumes an underlying geologically determined spatial variation, superimposed on which is a Gaussian stochastic process with Matérn correlation structure that models the observed tendency of dose rates in neighbouring houses to correlate. In the second approach, a number of dose-rate interpolation measures were first derived, based on averages over geologically or administratively defined areas or using distance-weighted averages of measurements at nearest-neighbour points. Linear regression was then used to derive an optimal linear combination of these interpolation measures. The predictive performances of the two models were compared via cross-validation, using a randomly selected 70 % of the data to fit the models and the remaining 30 % to test them. The mean square error (MSE) of the linear-regression model was lower than that of the Gaussian-Matérn model (MSE 378 and 411, respectively). The predictive performance of the two candidate models was also evaluated via simulation; the OLS model performs significantly better than the Gaussian-Matérn model. PMID:26880257

  1. Energy levels and radiative rates for transitions in Ti VI

    NASA Astrophysics Data System (ADS)

    Aggarwal, Kanti; Keenan, Francis; Msezane, Alfred Z.

    2012-06-01

    Energies for 568 levels among the n=3+3p^64l+3s3p^54l configurations of Ti VI are calculated using the GRASP (General-purpose Relativistic Atomic Structure Program) code, which is based on the multi-configuration Dirac-Fock (MCDF) method. Additionally, radiative rates are calculated for all types of transitions, namely electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2). Lifetimes are also calculated for all the levels and extensive comparisons are made with the earlier available data as well as with other parallel calculations from the FAC (Flexible Atomic Code). Discrepancies for several levels with the earlier calculations of Mohan et al, (ADNDT 93 105 (2007)) are highlighted.

  2. Risk evaluation - conventional and low level effects of radiation

    SciTech Connect

    Bond, V.P.; Varma, M.N.

    1984-04-01

    Any discussion of the risk of exposure to potentially-hazardous agents in the environment inevitably involves the question of whether the dose effect curve is of the threshold or linear, non-threshold type. A principal objective of this presentation is to show that the function is actually two separate relationships, each representing distinctly different functions with differing variables on the axes, and each characteristic of quite different functions with differing variables on the axes, and each characteristic of quite different disciplines (i.e., the threshold function, of Pharmacology, Toxicology and Medicine (PTM); the linear, non-threshold function, of Public Health including safety and accident statistics (PHS)). It is shown that low-level exposure (LLE) to radiation falls clearly in the PHS category. A function for cell dose vs. the fraction of single cell quantal responses is characterized, which reflects the absolute and relative sensitivities of cells. Acceptance of this function would obviate any requirement for the use in Radiation Protection of the concepts of a standard radiation, Q, dose equivalent and rem. 9 references, 4 figures.

  3. 41 CFR 50-204.35 - Application for variations from radiation levels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... variations from radiation levels. 50-204.35 Section 50-204.35 Public Contracts and Property Management Other... FOR FEDERAL SUPPLY CONTRACTS Radiation Standards § 50-204.35 Application for variations from radiation levels. (a) In accordance with policy expressed in the Federal Radiation Council's memorandum...

  4. Energy levels, lifetimes and radiative data of Ba XXVI

    NASA Astrophysics Data System (ADS)

    Singh, A. K.; Goyal, Arun; Khatri, Indu; Aggarwal, Sunny; Sharma, Rinku; Mohan, Man

    2016-05-01

    We report an extensive and an elaborate theoretical study of atomic data for Ba XXVI by considering Singlet, Doublet and Triplet (SDT) electron excitations within N-shell and single excitations from N-shell to O-shell. We have calculated energy levels and lifetimes for lowest 110 fine structure levels by using Multi-configuration Dirac-Fock method (MCDF). We have also considered Quantum Electrodynamics (QED) and Breit corrections in our calculations. We have presented the radiative data for electric and magnetic dipole (E1, M1) and quadrupole (E2, M2) transitions among lowest 110 levels. We have made comparisons of our calculated excitation energies and EUV (Extreme Ultraviolet) transition wavelengths with experimentally observed energy levels and wavelengths and achieved good agreement. We have also computed energy levels by performing similar relativistic distorted wave calculations using Flexible Atomic Code (FAC). Additionally, we have provided new atomic data for Ba XXVI which are not published elsewhere in the literature. We believe that our results may be beneficial in fusion plasma research and astrophysical investigations and applications.

  5. Solar Radiation Influence on Ground-Level Geomagnetic Perturbations

    NASA Astrophysics Data System (ADS)

    Weimer, D. R.; Clauer, C. R.

    2011-12-01

    An empirical model has been developed for predicting ground-level geomagnetic perturbations. Measurements from over 112 magnetometers were used, along with simultaneous observations of the solar wind and interplanetary magnetic field (IMF) from the ACE satellite. These data were from an eight-year period, from 1998 through 2005, covering both the rise and fall of the solar cycle. Variations in the solar radiation during this cycle are incorporated into the model, as determined by the F10.7 index of solar radio flux. Variations in ionospheric conductivity, under the influence of both season (dipole tilt angle) and solar radiation are implicitly included. Comparisons of model calculations with measurements at different locations show very good results. Maps of the magnetic perturbations for different conditions generally look as expected. Surprisingly, increasing the F10.7 index does not always increase the magnetic perturbations on the ground at all locations, as one might expect. The largest increases in the perturbations occur near the cusp when the IMF is Northward or has a strong Y component. However, in the nightside, as well as under the Region-2 currents, the ground-level perturbations are more likely to have a smaller magnitude with a higher F10.7 index.

  6. Radiation-induced response of operational amplifiers in low-level transient radiation environments

    SciTech Connect

    Paulos, J.J.; Bishop, R.J.; Turflinger, T.L.

    1987-12-01

    Extensive computer simulations have been performed on CMOS and bipolar operational amplifiers in an attempt to obtain a better understanding of low-level transient radiation response mechanisms. The simulation methodology has been confirmed using flash X-ray data for the amplifiers studied. Variations in circuit response to loading and feedback configuration have been explored, and several generalizations can be made which may provide a useful basis for a specification methodology.

  7. Nanodosimetry, from radiation physics to radiation biology.

    PubMed

    Grosswendt, B

    2005-01-01

    In view of the fact that early damage to genes and cells by ionising radiation starts with the early damage to segments of the DNA, it is a great challenge to radiation research to describe the general behaviour of ionising radiation in nanometric target volumes (nanodosimetry). After summarising basic aspects of nanodosimetry, an overview is given about its present state. As far as experimental procedures are concerned, main emphasis is laid on single-ion counting and single-electron counting methods, which use millimetric target volumes filled with a low-pressure gas to simulate nanometric target volumes at unit density. Afterwards, physical principles are discussed, which can be used to convert experimental ionisation cluster-size distributions into those caused by ionising radiation in liquid water. In the final section, possibilities are analysed of how to relate parameters derived from the probability of cluster-size formation in liquid water to parameters derived from radiobiological experiments. PMID:16381675

  8. Ionisation induced collapse of minihaloes

    NASA Astrophysics Data System (ADS)

    Back, Trevor

    2013-08-01

    In order to analyse the turbine blade life, the damage due to the combined thermal and mechanical loads should be adequately accounted for. This is more challenging when detailed component geometry is limited. Therefore, a compromise between the level of geometric detail and the complexity of the lifing method to be implemented would be necessary. This research focuses on how the life assessment of aero engine turbine blades can be done, considering the balance between available design inputs and adequate level of fidelity. Accordingly, the thesis contributes to developing a generic turbine blade lifing method that is based on the engine thermodynamic cycle; as well as integrating critical design/technological factors and operational parameters that influence the aero engine blade life. To this end, thermo-mechanical fatigue was identified as the critical damage phenomenon driving the life of the turbine blade.. The developed approach integrates software tools and numerical models created using the minimum design information typically available at the early design stages. Using finite element analysis of an idealised blade geometry, the approach captures relevant impacts of thermal gradients and thermal stresses that contribute to the thermo-mechanical fatigue damage on the gas turbine blade. The blade life is evaluated using the Neu/Sehitoglu thermo-mechanical fatigue model that considers damage accumulation due to fatigue, oxidation, and creep. The leading edge is examined as a critical part of the blade to estimate the damage severity for different design factors and operational parameters. The outputs of the research can be used to better understand how the environment and the operating conditions of the aircraft affect the

  9. Gain Calculations for Inner-Shell Lasing by Electron Collisional Ionisation

    NASA Astrophysics Data System (ADS)

    Upcraft, L. M.

    2002-11-01

    Current high power femtosecond lasers have been shown to produce electron pulses which may be appropriate for the pumping of X-Ray lasers through collisional ionisation. Non-radiative Coster-Kronig type decay processes may be fast enough to form an inverted state and allow X-ray lasing within the biologically interesting "water window". Calculations of the atomic processes in metallic Ti, Mn and Cu are presented that potentially useable gains on the M1 - L3 transition.

  10. Grad-Level Radiation Damage of SIO2 Detectors

    SciTech Connect

    Simos, N.; Atoian, G.; Ludewig, H; White, S; O'Conor, J; Mokhov, N.V.

    2009-05-04

    Radiation effects and levels to detectors. SiO{sub 2} quartz fibers of the LHC ATLAS Zero-degree Calorimeter (ZDC) anticipated to experience integrated doses of a few Grad at their closest position were exposed to 200 MeV protons and neutrons at the Brookhaven National Laboratory (BNL) Linac. Specifically, 1 mm- and 2mm-diameter quartz (GE 124) rods were exposed to direct 200 MeV protons during the first phase of exposure leading to peak integrated dose of {approx}28 Grad. Exposure to a primarily neutron flux of 1mm-diameter SiO{sub 2} fibers was also achieved with a special neutron source arrangement. In a post-irradiation analysis the quartz fiber transmittance was evaluated as a function of the absorbed dose. Dramatic degradation of the transmittance property was observed with increased radiation damage. In addition, detailed evaluation of the fibers under the microscope revealed interesting micro-structural damage features and irradiation-induced defects.

  11. Low Level Laser Therapy: laser radiation absorption in biological tissues

    NASA Astrophysics Data System (ADS)

    Di Giacomo, Paola; Orlando, Stefano; Dell'Ariccia, Marco; Brandimarte, Bruno

    2013-07-01

    In this paper we report the results of an experimental study in which we have measured the transmitted laser radiation through dead biological tissues of various animals (chicken, adult and young bovine, pig) in order to evaluate the maximum thickness through which the power density could still produce a reparative cellular effect. In our experiments we have utilized a pulsed laser IRL1 ISO model (based on an infrared diode GaAs, λ=904 nm) produced by BIOMEDICA s.r.l. commonly used in Low Level Laser Therapy. Some of the laser characteristics have been accurately studied and reported in this paper. The transmission results suggest that even with tissue thicknesses of several centimeters the power density is still sufficient to produce a cell reparative effect.

  12. Deep levels and radiation effects in p-InP

    NASA Technical Reports Server (NTRS)

    Anderson, W. A.; Singh, A.; Jiao, K.; Lee, B.

    1989-01-01

    A survey was conducted on past studies of hole traps in InP. An experiment was designed to evaluate hole traps in Zn-doped InP after fabrication, after electron irradiation and after annealing using deep level transient spectroscopy. Data similar to that of Yamaguchi was seen with observation of both radiation-induced hole and electron traps at E sub A=0.45 eV and 0.03 eV, respectively. Both traps are altered by annealing. It is also shown that trap parameters for surface-barrier devices are influenced by many factors such as bias voltage, which probes traps at different depths below the surface. These devices require great care in data evaluation.

  13. 10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Limits on external radiation levels from storage... INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.21 Limits on external radiation levels from storage containers and source changers. The...

  14. 10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Limits on external radiation levels from storage containers and source changers. 34.21 Section 34.21 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.21 Limits on external radiation levels...

  15. 49 CFR 173.441 - Radiation level limitations and exclusive use provisions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Radiation level limitations and exclusive use... Radiation level limitations and exclusive use provisions. (a) Except as provided in paragraph (b) of this... prepared for shipment, so that under conditions normally incident to transportation, the radiation...

  16. 49 CFR 173.441 - Radiation level limitations and exclusive use provisions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Radiation level limitations and exclusive use... Radiation level limitations and exclusive use provisions. (a) Except as provided in paragraph (b) of this... prepared for shipment, so that under conditions normally incident to transportation, the radiation...

  17. The nature of the ionised nebula surrounding the red supergiant W26

    NASA Astrophysics Data System (ADS)

    Wesson, Roger

    2015-08-01

    The red supergiant W26 in the massive star cluster Westerlund 1 is surrounded by a compact ionised nebula. This is unique among RSGs, and the excitation mechanism of the nebula is not yet known - it may be ionised by an unseen compact companion, or by a nearby blue supergiant. We present new observations of the nebula: high resolution spatially resolved spectra taken with FLAMES at the VLT show that the nebula is a ring, with velocities consistent with that expected for red supergiant ejecta, and ruling out the possibility of a Luminous Blue Variable-type eruption preceding the RSG phase as the origin of the nebula. A triangular patch of nebulosity outside the ring appears to be associated with W26, and may be material stripped from the expanding ring by the cumulative cluster wind and radiation field.

  18. Measurement of the natural radiation background level of Riyadh City

    SciTech Connect

    Al-Kusayer, T.A.; Al-Haj, A.N.

    1987-01-01

    A gamma spectroscopy system was used to analyze the radionuclides in soil samples and to determine the cumulative radioactivity of terrestrial origin in the Riyadh City area. Minimal work has been done in the 1980s to measure the natural background radiation level in Saudi Arabia by using thermoluminescent dosimeters. The measurement of the natural radioactivity in the Riyadh area for the radionuclide concentration in becquerels per kilogram, the exposure rate arising from radionuclides in grays per hour, and the equivalent dose rate in sieverts per hour are the goals of this work. Soil samples were collected from 21 places in Riyadh City. Each site was sampled for two depth profiles, 0 to 5 cm and 5 to 15 cm. These measurements were taken before the Chernobyl accident, and in the absence of any measurements for that area in the past, this work can be considered in future work for a reference /sup 137/Cs concentration in Riyadh soil to determine the /sup 137/Cs increase in the soil after the Chernobyl accident.

  19. The use of particle beam mass spectrometry for the measurement of impurities in a nabumetone drug substance, not easily amenable to atmospheric pressure ionisation techniques.

    PubMed

    Wolff, J C; Hawtin, P N; Monté, S; Balogh, M; Jones, T

    2001-01-01

    Liquid chromatography/particle beam mass spectrometry (LC/PB-MS) was used for the structural elucidation of some impurities in nabumetone as this compound poorly ionises by atmospheric pressure ionisation (API) techniques. PB-MS was optimised for nabumetone and a sensitivity study was carried out. To obtain full scan electron ionisation spectra a minimum of 100 ng of compound on column was needed. By using 20 mg/mL solutions of nabumetone, impurities at levels of about 250 ppm mass fraction relative to nabumetone could be detected. Results were compared with LC/API-MS and previous GC/MS. PMID:11223957

  20. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain...

  1. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain...

  2. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain...

  3. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to radiation. (a) If one or more of the sources in § 79.43(a) contain...

  4. Ionisation and discharge in cloud-forming atmospheres of brown dwarfs and extrasolar planets

    NASA Astrophysics Data System (ADS)

    Helling, Ch; Rimmer, P. B.; Rodriguez-Barrera, I. M.; Wood, Kenneth; Robertson, G. B.; Stark, C. R.

    2016-07-01

    Brown dwarfs and giant gas extrasolar planets have cold atmospheres with rich chemical compositions from which mineral cloud particles form. Their properties, like particle sizes and material composition, vary with height, and the mineral cloud particles are charged due to triboelectric processes in such dynamic atmospheres. The dynamics of the atmospheric gas is driven by the irradiating host star and/or by the rotation of the objects that changes during its lifetime. Thermal gas ionisation in these ultra-cool but dense atmospheres allows electrostatic interactions and magnetic coupling of a substantial atmosphere volume. Combined with a strong magnetic field \\gg {{B}\\text{Earth}} , a chromosphere and aurorae might form as suggested by radio and x-ray observations of brown dwarfs. Non-equilibrium processes like cosmic ray ionisation and discharge processes in clouds will increase the local pool of free electrons in the gas. Cosmic rays and lighting discharges also alter the composition of the local atmospheric gas such that tracer molecules might be identified. Cosmic rays affect the atmosphere through air showers in a certain volume which was modelled with a 3D Monte Carlo radiative transfer code to be able to visualise their spacial extent. Given a certain degree of thermal ionisation of the atmospheric gas, we suggest that electron attachment to charge mineral cloud particles is too inefficient to cause an electrostatic disruption of the cloud particles. Cloud particles will therefore not be destroyed by Coulomb explosion for the local temperature in the collisional dominated brown dwarf and giant gas planet atmospheres. However, the cloud particles are destroyed electrostatically in regions with strong gas ionisation. The potential size of such cloud holes would, however, be too small and might occur too far inside the cloud to mimic the effect of, e.g. magnetic field induced star spots.

  5. New techniques of low level environmental radiation monitoring at JLab

    SciTech Connect

    P. Degtiarenko, V. Popov

    2010-07-01

    We present the first long-term environmental radiation monitoring results obtained using the technique of pulse mode readout for the industry-standard Reuter-Stokes RSS-1013 argon-filled high pressure ionization chambers (HPIC). With novel designs for the front-end electronics readout and customized signal processing algorithms, we are capable of detecting individual events of gas ionization in the HPIC, caused by interactions of gammas and charged particles in the gas. The technique provides enough spectroscopic information to distinguish between several different types of environmental and man-made radiation. The technique also achieves a high degree of sensitivity and stability of the data, allowing long-term environmental radiation monitoring with unprecedented precision.

  6. 10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Limits on external radiation levels from storage containers and source changers. 34.21 Section 34.21 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR... § 34.21 Limits on external radiation levels from storage containers and source changers. The...

  7. 10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Limits on external radiation levels from storage containers and source changers. 34.21 Section 34.21 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR... § 34.21 Limits on external radiation levels from storage containers and source changers. The...

  8. 10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Limits on external radiation levels from storage containers and source changers. 34.21 Section 34.21 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR... § 34.21 Limits on external radiation levels from storage containers and source changers. The...

  9. 28 CFR 79.44 - Proof of working level month exposure to radiation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Proof of working level month exposure to radiation. 79.44 Section 79.44 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility Criteria for Claims by Uranium Miners § 79.44 Proof of working level month exposure to...

  10. Classification of the Spectra of Highly Ionised Atoms During the Last Seven Years

    NASA Astrophysics Data System (ADS)

    Fawcett, B. C.

    1981-10-01

    This review of recent contributions to the classification of the spectra of highly ionised atoms emphasises how major research projects have influenced progress. These projects include experiments on board orbiting space satellites and SKYLAB, those of fusion research (notably involving TOKAMAK devices), studies with giant pulse laser-produced-plasmas and beam-foil spectroscopy. In addition, the large volume of data gathered through the application of traditional methods and the impact of theoretical calculations are discussed. A comprehensive reference list of papers reporting emission line identifications for elements lighter than nickel and ionisation stages higher than the fourth is included, along with references to other bibliographies and compilations of energy levels, or wavelengths and identifications.

  11. The effect of highly ionising particles on the CMS silicon strip tracker

    NASA Astrophysics Data System (ADS)

    Adam, W.; Bergauer, T.; Friedl, M.; Fruehwirth, R.; Hrubec, J.; Krammer, M.; Pernicka, M.; Waltenberger, W.; Beaumont, W.; de Langhe, E.; de Wolf, E.; Tasevsky, M.; Bouhali, O.; Clerbaux, B.; de Lentdecker, G.; Dewulf, J.-P.; Neuckermans, L.; Vander-Velde, C.; Vanlaer, P.; Wickens, J.; D'Hondt, J.; Goorens, R.; Heyninck, J.; Lowette, S.; Tavernier, S.; Van Lancker, L.; Yu, C.; Assouak, S.; Bonnet, J.-L.; Bruno, G.; De-Callatay, B.; De-Favereau-de-Jeneret, J.; Delaere, C.; De-Visscher, S.; Favart, D.; Gregoire, G.; Keutgen, Th.; Leibenguth, G.; Lemaitre, V.; Michotte, D.; Militaru, O.; Ninane, A.; Ovyn, S.; Piotrzkowski, K.; Roberfroid, V.; Rouby, X.; Van-der-Aa, O.; Vander-Donckt, M.; Boulogne, I.; Daubie, E.; Defontaines, F.; Herquet, P.; Czellar, S.; Härkönen, J.; Karimäki, V.; Katajisto, H.; Linden, T.; Luukka, P.; Lampen, T.; Mäenpää, T.; Tuominen, E.; Tuominiemi, J.; Tuuva, T.; Ageron, M.; Chabanat, E.; Contardo, D.; Estre, N.; Haroutunian, R.; Lumb, N.; Mirabito, L.; Perries, S.; Trocme, B.; Blaes, R.; Charles, F.; Drouhin, F.; Ernenwein, J. P.; Fontaine, J. C.; Berst, J. D.; Brom, J. M.; Didierjean, F.; Goerlach, U.; Gross, L.; Juillot, P.; Lounis, A.; Maazouzi, C.; Olivetto, C.; Strub, R.; Vanhove, P.; Vintache, D.; Adolphi, R.; Brauer, R.; Braunschweig, W.; Esser, H.; Feld, L.; Heister, A.; Karpinski, W.; Klein, K.; König, S.; Kukulies, C.; Olzem, J.; Ostaptchouk, A.; Pandoulas, D.; Pierschel, G.; Raupach, F.; Schael, S.; Schultz von Dratzig, A.; Schwering, G.; Siedling, R.; Thomas, M.; Wlochal, M.; Beissel, F.; Boffin, K.-D.; Duda, M.; Flossdorf, A.; Flugge, G.; Franke, T.; Hangarter, K.; Hegner, B.; Hermanns, Th.; Kasselmann, S.; Kress, Th.; Linn, A.; Mnich, J.; Nowack, A.; Poettgens, M.; Pooth, O.; Reinhold, B.; Bleyl, M.; Holm, U.; Klanner, R.; Pein, U.; Schleper, P.; Schirm, N.; Steinbrück, G.; Stoye, M.; Tesch, S.; van Staa, R.; Wick, K.; Atz, B.; Barvich, T.; Blum, P.; de Boer, W.; Boegelspacher, F.; Dirkes, G.; Fahrer, M.; Fernandez, J.; Frey, M.; Furgeri, A.; Grigoriev, E.; Hartmann, F.; Heier, S.; Muller, T.; Ortega-Gomez, T.; Simonis, H.-J.; Steck, P.; Theel, A.; Weiler, T.; Zhukov, V.; Creanza, D.; De Filippis, N.; de Palma, M.; De Robertis, G.; Fiore, L.; Giordano, D.; Maggi, G.; Mennea, M.; My, S.; Radicci, V.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Albergo, S.; Bellini, V.; Chiorboli, M.; Costa, S.; Potenza, R.; Sutera, C.; Tricomi, A.; Tuvè, C.; Bocci, A.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Landi, G.; Macchiolo, A.; Magini, N.; Mersi, S.; Marchettini, C.; Meschini, M.; Paoletti, S.; Parrini, G.; Ranieri, R.; Sani, M.; Bacchetta, N.; Bisello, D.; Candelori, A.; Dorigo, T.; Giubilato, P.; Kaminsky, A.; Loreti, M.; Nigro, M.; Paccagnella, A.; Rando, R.; Angarano, M. M.; Babucci, E.; Benedetti, D.; Biasini, M.; Bilei, G. M.; Brunetti, M. T.; Checcucci, B.; Dinu, N.; Fanò, L.; Giorgi, M.; Lariccia, P.; Mantovani, G.; Postolache, V.; Puscalau, M.; Ricci, D.; Santinelli, R.; Santocchia, A.; Servoli, L.; Zucchetti, C.; Azzurri, P.; Bagliesi, G.; Basti, A.; Bernardini, J.; Boccali, T.; Borrello, L.; Bosi, F.; Castaldi, R.; D'Alfonso, M.; Dell'Orso, R.; Dutta, S.; Foa, L.; Gennai, S.; Giammanco, A.; Giassi, A.; Lomtadze, T.; Mangano, B.; Messineo, A.; Moggi, A.; Palla, F.; Palmonari, F.; Raffaelli, F.; Rizzi, A.; Rizzi, D.; Segneri, G.; Sentenac, D.; Sguazzoni, G.; Spagnolo, P.; Tonelli, G.; Verdini, P. G.; Biino, C.; Costa, M.; Demaria, N.; Favro, G.; Trapani, P.; Peroni, C.; Romero, A.; Migliore, E.; Abbaneo, D.; Ahmed, F.; Bartalini, P.; Bernardino-Rodriguez, N.; Breuker, H.; Buchmuller, O.; Carrone, E.; Cattai, A.; Chierici, R.; Cucciarelli, S.; Dierlamm, A.; Eppard, M.; Frey, A.; Gill, K.; Grabit, R.; Honma, A.; Huhtinen, M.; Magazzu, G.; Mannelli, M.; Marchioro, A.; Onnela, A.; Perea-Solano, B.; Petagna, P.; Postema, H.; Risoldi, M.; Rolandi, G.; Siegrist, P.; Troska, I.; Tsirou, A.; Vasey, F.; Weber, M.; Wittmer, B.; Bertl, W.; Gabathuler, K.; Horisberger, R.; Kästli, H.-Ch.; Kotlinski, D.; MacPherson, A.; Rohe, T.; Freudenreich, K.; Lustermann, W.; Pauss, F.; Eichler, R.; Erdmann, W.; Grab, C.; Schoning, A.; Amsler, C.; Chiochia, V.; Dorokhov, A.; Hörmann, C.; Pruys, H.; Prokofiev, K.; Regenfus, C.; Robmann, P.; Speer, T.; Bell, K. W.; Coughlan, J.; French, M.; Halsall, R.; Jones, L.; Pearson, M.; Rogers, G.; Tomalin, I.; Bainbridge, R.; Barrillon, P.; Colling, D.; Dris, S.; Foudas, C.; Fulcher, J.; Hall, G.; Iles, G.; Jones, J.; Leaver, J.; Macevoy, B. C.; Noy, M.; Raymond, D. M.; Takahashi, M.; Zorba, O.; Barnett, B.; Chien, C.-Y.; Kim, D. W.; Liang, G.; Swartz, M.; Atac, M.; Demarteau, M.; Joshi, U.; Kwan, S.; Spiegel, L.; Tkaczyk, S.; Gerber, C. E.; Shabalina, E.; Ten, T.; Lander, R.; Pellett, D.; Gobbi, B.; Kubantsev, M.; Malik, S.; Tilden, R.; Baringer, P.; Bean, A.; Christofek, L.; Coppage, D.; Bolton, T. A.; Demina, R.; Kahl, W. E.; Khanov, A.; Korjenevski, S.; Pukhaeva, N.; Reay, N. W.; Rizatdinova, F.; Sidwell, R. A.; Stanton, N. R.; Cremaldi, L.; Sanders, D.; Bartz, E.; Doroshenko, J.; Koeth, T.; Perera, L.; Schnetzer, S.; Stone, R.; Worm, S.; Gartung, P.; Hanson, G. G.; Jeng, G. Y.; Páztor, G.; Eusebi, R.; Halkiadakis, E.; Hocker, A.; Tipton, P.; Affolder, A.; Campagnari, C.; Hale, D.; Incandela, J.; Kyre, S.; Lamb, J.; Taylor, R.; White, D.; Bolla, G.; Bortoletto, D.; Garfinkel, A.; Rott, C.; Roy, A.

    2005-05-01

    Inelastic nuclear collisions of hadrons incident on silicon sensors can generate secondary highly ionising particles (HIPs) and deposit as much energy within the sensor bulk as several hundred minimum ionising particles. The large signals generated by these 'HIP events' can momentarily saturate the APV25 front-end readout chip for the silicon strip tracker (SST) sub-detector of the compact muon solenoid (CMS) experiment, resulting in deadtime in the detector readout system. This paper presents studies of this phenomenon through simulation, laboratory measurements and dedicated beam tests. A proposed change to a front-end component to reduce the APV25 sensitivity to HIP events is also examined. The results are used to infer the expected effect on the performance of the CMS SST at the future large hadron collider. The induced inefficiencies are at the percent level and will have a negligible effect on the physics performance of the SST.

  12. A theoretical concept of low level/low LET radiation carcinogenic risk (LLCR) projection

    SciTech Connect

    Filyushkin, I.V.

    1992-06-01

    Carcinogenic risk to humans resulting from low level/low LET radiation exposure (LLLCR) has not been observed directly because epidemiological observations have not yet provided statistically significant data on risk values. However, these values are of great interest for radiation health science and radiation protection practice under both normal conditions and emergency situations. This report presents a theoretical contribution to the validation of dose and dose rate efficiency factors (DDREF) transforming cocinogenic risk coefficients from those revealed in A-bomb survivors to factors appropriate for the projection of the risk resulting from very low levels of low LET radiation.

  13. Surface solar ultraviolet radiation for paleoatmospheric levels of oxygen and ozone

    NASA Technical Reports Server (NTRS)

    Levine, J. S.

    1980-01-01

    Many investigators have concluded that the level of solar ultraviolet radiation (200-300 nm) reaching the surface was a key parameter in the origin and evolution of life on earth. The level of solar ultraviolet radiation between 200 and 300 nm is controlled primarily by molecular absorption by ozone, whose presence is strongly coupled to the level of molecular oxygen. In this paper, a series of calculations is presented of the solar ultraviolet radiation reaching the surface for oxygen levels ranging from 0.0001 the present atmospheric level to the present level. The solar spectrum between 200 and 300 nm has been divided into 34 spectral intervals. For each spectral interval, the solar ultraviolet radiation reaching the earth's surface has been calculated by considering the attenuation of the incoming beam due to ozone and oxygen absorption. A one-dimensional photochemical model of the atmosphere was used for these calculations.

  14. Resistance of Feather-Associated Bacteria to Intermediate Levels of Ionizing Radiation near Chernobyl

    PubMed Central

    Ruiz-González, Mario Xavier; Czirják, Gábor Árpád; Genevaux, Pierre; Møller, Anders Pape; Mousseau, Timothy Alexander; Heeb, Philipp

    2016-01-01

    Ionizing radiation has been shown to produce negative effects on organisms, although little is known about its ecological and evolutionary effects. As a study model, we isolated bacteria associated with feathers from barn swallows Hirundo rustica from three study areas around Chernobyl differing in background ionizing radiation levels and one control study site in Denmark. Each bacterial community was exposed to four different γ radiation doses ranging from 0.46 to 3.96 kGy to test whether chronic exposure to radiation had selected for resistant bacterial strains. Experimental radiation duration had an increasingly overall negative effect on the survival of all bacterial communities. After exposure to γ radiation, bacteria isolated from the site with intermediate background radiation levels survived better and produced more colonies than the bacterial communities from other study sites with higher or lower background radiation levels. Long-term effects of radiation in natural populations might be an important selective pressure on traits of bacteria that facilitate survival in certain environments. Our findings indicate the importance of further studies to understand the proximate mechanisms acting to buffer the negative effects of ionizing radiation in natural populations. PMID:26976674

  15. Resistance of Feather-Associated Bacteria to Intermediate Levels of Ionizing Radiation near Chernobyl.

    PubMed

    Ruiz-González, Mario Xavier; Czirják, Gábor Árpád; Genevaux, Pierre; Møller, Anders Pape; Mousseau, Timothy Alexander; Heeb, Philipp

    2016-01-01

    Ionizing radiation has been shown to produce negative effects on organisms, although little is known about its ecological and evolutionary effects. As a study model, we isolated bacteria associated with feathers from barn swallows Hirundo rustica from three study areas around Chernobyl differing in background ionizing radiation levels and one control study site in Denmark. Each bacterial community was exposed to four different γ radiation doses ranging from 0.46 to 3.96 kGy to test whether chronic exposure to radiation had selected for resistant bacterial strains. Experimental radiation duration had an increasingly overall negative effect on the survival of all bacterial communities. After exposure to γ radiation, bacteria isolated from the site with intermediate background radiation levels survived better and produced more colonies than the bacterial communities from other study sites with higher or lower background radiation levels. Long-term effects of radiation in natural populations might be an important selective pressure on traits of bacteria that facilitate survival in certain environments. Our findings indicate the importance of further studies to understand the proximate mechanisms acting to buffer the negative effects of ionizing radiation in natural populations. PMID:26976674

  16. Improvements in extremity dose assessment for ionising radiation medical applications.

    PubMed

    Ginjaume, M; Pérez, S; Ortega, X

    2007-01-01

    This study aims at testing the INTE ring dosemeter based on MCP-Ns and TLD-100 detectors on users from the field of medical applications, namely radiopharmacists, personnel at a cyclotron facility with corresponding FDG synthesis cells, interventional radiology technologists and radiologists. These users were chosen due to the fact that they have a significantly high risk of exposure to their hands. Following previous results, MCP-Ns TL thin material was used for radiology measurements, whereas TLD-100 was preferred for other applications. The dosemeters were tested to make sure that they were waterproof and that they could be sterilised properly prior to use. Results confirm the need to implement finger dosimetry, mainly for interventional radiologists as finger dose can be >50 times higher than whole-body dose and 3 times higher than wrist dose. PMID:17277325

  17. Hand exposure to ionising radiation of nuclear medicine workers.

    PubMed

    Wrzesień, M; Olszewski, J; Jankowski, J

    2008-01-01

    The specific nature of work in nuclear medicine departments involves the use of isotopes and handling procedures, which contribute to the considerable value of an equivalent dose received, in particular, by the fingertips. Standard nuclear medicine department uses ring dosemeters placed usually at the base of the middle finger. The main aim of the study was to find out whether a relationship exists between the doses recorded by thermoluminescent detectors placed at various locations on the radiopharmacists' hands and the doses recorded by the ring detectors, and to determine the character of that relationship. The correction factor represents a correction value to be used to calculate the doses which might be received by locations on the hand from the dose recorded by the ring dosemeter. The dose recorded by the ring dosemeter is on the average five times lower than that received by the fingertips of thumb, index and middle fingers. PMID:18310609

  18. Health effects of low-level radiation in shipyard workers. Final report: [Draft

    SciTech Connect

    Matanoski, G.M.

    1991-06-01

    The Nuclear Shipyard Workers Study (NSWS) was designed to determine whether there is an excess risk of leukemia or other cancers associated with exposure to low levels of gamma radiation. The study compares the mortality experience of shipyard workers who qualified to work in radiation areas to the mortality of similar workers who hold the same types of jobs but who are not authorized to work in radiation areas. The population consists of workers from six government and two private shipyards.

  19. Calculating far-field radiated sound pressure levels from NASTRAN output

    NASA Technical Reports Server (NTRS)

    Lipman, R. R.

    1986-01-01

    FAFRAP is a computer program which calculates far field radiated sound pressure levels from quantities computed by a NASTRAN direct frequency response analysis of an arbitrarily shaped structure. Fluid loading on the structure can be computed directly by NASTRAN or an added-mass approximation to fluid loading on the structure can be used. Output from FAFRAP includes tables of radiated sound pressure levels and several types of graphic output. FAFRAP results for monopole and dipole sources compare closely with an explicit calculation of the radiated sound pressure level for those sources.

  20. The ST environment: Expected charged particle radiation levels

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.

    1978-01-01

    The external (surface incident) charged particle radiation, predicted for the ST satellite at the three different mission altitudes, was determined in two ways: (1) by orbital flux-integration and (2) by geographical instantaneous flux-mapping. The latest standard models of the environment were used in this effort. Magnetic field definitions for three nominal circular trajectories and for the geographic mapping positions were obtained from a current field model. Spatial and temporal variations or conditions affecting the static environment models were considered and accounted for, wherever possible. Limited shielding and dose evaluations were performed for a simple geometry. Results, given in tabular and graphical form, are analyzed, explained, and discussed. Conclusions are included.

  1. Radiation properties and emissivity parameterization of high level thin clouds

    NASA Technical Reports Server (NTRS)

    Wu, M.-L. C.

    1984-01-01

    To parameterize emissivity of clouds at 11 microns, a study has been made in an effort to understand the radiation field of thin clouds. The contributions to the intensity and flux from different sources and through different physical processes are calculated by using the method of successive orders of scattering. The effective emissivity of thin clouds is decomposed into the effective absorption emissivity, effective scattering emissivity, and effective reflection emissivity. The effective absorption emissivity depends on the absorption and emission of the cloud; it is parameterized in terms of optical thickness. The effective scattering emissivity depends on the scattering properties of the cloud; it is parameterized in terms of optical thickness and single scattering albedo. The effective reflection emissivity follows the similarity relation as in the near infrared cases. This is parameterized in terms of the similarity parameter and optical thickness, as well as the temperature difference between the cloud and ground.

  2. Ambient radiation levels in positron emission tomography/computed tomography (PET/CT) imaging center

    PubMed Central

    Santana, Priscila do Carmo; de Oliveira, Paulo Marcio Campos; Mamede, Marcelo; Silveira, Mariana de Castro; Aguiar, Polyanna; Real, Raphaela Vila; da Silva, Teógenes Augusto

    2015-01-01

    Objective To evaluate the level of ambient radiation in a PET/CT center. Materials and Methods Previously selected and calibrated TLD-100H thermoluminescent dosimeters were utilized to measure room radiation levels. During 32 days, the detectors were placed in several strategically selected points inside the PET/CT center and in adjacent buildings. After the exposure period the dosimeters were collected and processed to determine the radiation level. Results In none of the points selected for measurements the values exceeded the radiation dose threshold for controlled area (5 mSv/year) or free area (0.5 mSv/year) as recommended by the Brazilian regulations. Conclusion In the present study the authors demonstrated that the whole shielding system is appropriate and, consequently, the workers are exposed to doses below the threshold established by Brazilian standards, provided the radiation protection standards are followed. PMID:25798004

  3. Generation of GW-Level, Sub-Angstrom Radiation in the LCLS Using a Second-Harmonic Radiator

    SciTech Connect

    Huang, Z

    2004-09-14

    Electron beams are strongly microbunched near the high-gain free-electron laser (FEL) saturation with a rich harmonic content in the beam current. While the coherent harmonic emission is possible in a planar undulator, the third-harmonic radiation typically dominates with about 1% of the fundamental power at saturation. In this paper, we discuss the second-harmonic radiation in the Linac Coherent Light Source. We show that by a suitable design of an second-stage undulator with its fundamental frequency tuned to the second harmonic of the first undulator, coherent second-harmonic radiation much more intense than the third-harmonic is emitted. Numerical simulations predict that GW-level, sub-Angstrom x-ray pulses can be generated in a relatively short second-harmonic radiator.

  4. Cosmic-ray ionisation of dense molecular clouds

    NASA Astrophysics Data System (ADS)

    Vaupre, Solenn

    2015-07-01

    Cosmic rays (CR) are of tremendous importance in the dynamical and chemical evolution of interstellar molecular clouds, where stars and planets form. CRs are likely accelerated in the shells of supernova remnants (SNR), thus molecular clouds nearby can be irradiated by intense fluxes of CRs. CR protons have two major effects on dense molecular clouds: 1) when they encounter the dense medium, high-energy protons (>280 MeV) create pions that decay into gamma-rays. This process makes SNR-molecular cloud associations intense GeV and/or TeV sources whose spectra mimic the CR spectrum. 2) at lower energies, CRs penetrate the cloud and ionise the gas, leading to the formation of molecular species characteristic of the presence of CRs, called tracers of the ionisation. Studying these tracers gives information on low-energy CRs that are unaccessible to any other observations. I studied the CR ionisation of molecular clouds next to three SNRs: W28, W51C and W44. These SNRs are known to be interacting with the nearby clouds, from the presence of shocked gas, OH masers and pion-decay induced gamma-ray emission. My work includes millimeter observations and chemical modeling of tracers of the ionisation in these dense molecular clouds. In these three regions, we determined an enhanced CR ionisation rate, supporting the hypothesis of an origin of the CRs in the SNR nearby. The evolution of the CR ionisation rate with the distance to the SNR brings valuable constraints on the propagation properties of low-energy CRs. The method used relies on observations of the molecular ions HCO+ and DCO+, which shows crucial limitations at high ionisation. Therefore, I investigated, both through modeling and observations, the chemical abundances of several other species to try and identity alternative tracers of the ionisation. In particular, in the W44 region, observations of N2H+ bring additional constraints on the physical conditions, volatile abundances in the cloud, and the ionisation

  5. The assessment of risks from exposure to low-levels of ionizing radiation

    SciTech Connect

    Gilbert, E.S.

    1992-06-01

    This report is concerned with risk assessments for human populations receiving low level radiation doses; workers routinely exposed to radiation, Japanese victims of nuclear bombs, and the general public are all considered. Topics covered include risk estimates for cancer, mortality rates, risk estimates for nuclear site workers, and dosimetry.

  6. [Radiation-induced cancers].

    PubMed

    Dutrillaux, B

    1998-01-01

    The induction of malignant diseases is one of the most concerning late effects of ionising radiation. A large amount of information has been collected form atomic bomb survivors, patients after therapeutic irradiation, occupational follow-up and accidentally exposed populations. Major uncertainties persist in the (very) low dose range i.e., population and workers radioprotection. A review of the biological mechanisms leading to cancer strongly suggests that the vast majority of radiation-induced malignancies arise as a consequence of recessive mutations of tumour-suppressor genes. These mutations can be unveiled by ageing, this process being possibly furthered by constitutional or acquired genomic instability. The individual risk is likely to be very low, probably because of the usual dose level. However, the magnitude of medical exposure and the reliance of our societies on nuclear industry are so high that irreproachable decision-making processes and standards for practice are inescapable. PMID:9868399

  7. 10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... environmental radiation standards in 40 CFR part 190, levels of radiation or releases of radioactive material in... 10 Energy 1 2010-01-01 2010-01-01 false Reports of exposures, radiation levels, and concentrations... REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Reports § 20.2203 Reports of...

  8. Effects of combined radiofrequency radiation exposure on levels of reactive oxygen species in neuronal cells.

    PubMed

    Kang, Kyoung Ah; Lee, Hyung Chul; Lee, Je-Jung; Hong, Mi-Na; Park, Myung-Jin; Lee, Yun-Sil; Choi, Hyung-Do; Kim, Nam; Ko, Young-Gyu; Lee, Jae-Seon

    2014-03-01

    The objective of this study was to investigate the effects of the combined RF radiation (837 MHz CDMA plus 1950 MHz WCDMA) signal on levels of intracellular reactive oxygen species (ROS) in neuronal cells. Exposure of the combined RF signal was conducted at specific absorption rate values of 2 W/kg of CDMA plus 2 W/kg of WCDMA for 2 h. Co-exposure to combined RF radiation with either H2O2 or menadione was also performed. The experimental exposure groups were incubator control, sham-exposed, combined RF radiation-exposed with or without either H2O2 or menadione groups. The intracellular ROS level was measured by flow cytometry using the fluorescent probe dichlorofluorescein diacetate. Intracellular ROS levels were not consistently affected by combined RF radiation exposure alone in a time-dependent manner in U87, PC12 or SH-SY5Y cells. In neuronal cells exposed to combined RF radiation with either H2O2 or menadione, intracellular ROS levels showed no statically significant alteration compared with exposure to menadione or H2O2 alone. These findings indicate that neither combined RF radiation alone nor combined RF radiation with menadione or H2O2 influences the intracellular ROS level in neuronal cells such as U87, PC12 or SH-SY5Y. PMID:24105709

  9. Scientific view of low-level radiation risks

    SciTech Connect

    Hall, E.J. )

    1991-05-01

    The average number of diagnostic x-ray procedures per year in the United States equals the total population and results in an annual collective effective dose equivalent of about 9 million person-rem. Possible deleterious effects include (a) genetic consequences, the risks of which can be assessed only from animal studies; (b) carcinogenesis, which can be assessed from survivors of nuclear bombings and patients exposed for medical reasons; and (c) effects on the developing embryo or fetus. For stochastic endpoints such as cancer and genetic anomalies, it is estimated that the current practice of radiology in the United States increases spontaneous frequency by less than 1%. No single procedure is likely to produce harm to the conceptus, but an accumulation of procedures in a pregnant woman could be hazardous during the sensitive period of 8-15 weeks after conception, with microcephaly and mental retardation the most likely deleterious effects. The balance of risk versus benefit in diagnostic radiology is heavily weighted toward benefit, but the risks are there, and constant efforts are needed to reduce radiation doses to the minimum necessary.

  10. Base-level management of radio-frequency radiation-protection program. Final report

    SciTech Connect

    Rademacher, S.E.; Montgomery, N.D.

    1989-04-01

    AFOEHL developed this report to assist the base-level aerospace medical team manage their radio-frequency radiation-protection program. This report supersedes USAFOEHL Report 80-42, 'A Practical R-F Guide for BEES.'

  11. Base-level management of radio-frequency radiation-protection program. Final report

    SciTech Connect

    Rademacher, S.E.; Montgomery, N.D.

    1989-04-01

    AFOEHL developed this report to assist the base-level aerospace medical team manage their radio-frequency radiation protection program. This report supersedes USAFOEHL Report 80-42, 'A practical R-F Guide for BEES.'

  12. Infrared radiation and inversion population of CO2 laser levels in Venusian and Martian atmospheres

    NASA Technical Reports Server (NTRS)

    Gordiyets, B. F.; Panchenko, V. Y.

    1983-01-01

    Formation mechanisms of nonequilibrium 10 micron CO2 molecule radiation and the possible existence of a natural laser effect in the upper atmospheres of Venus and Mars are theoretically studied. An analysis is made of the excitation process of CO2 molecule vibrational-band levels (with natural isotropic content) induced by direct solar radiation in bands 10.6, 9.4, 4.3, 2.7 and 2.0 microns. The model of partial vibrational-band temperatures was used in the case. The problem of IR radiation transfer in vibrational-rotational bands was solved in the radiation escape approximation.

  13. Further Studies of Ground-Level Auroral Kilometric Radiation

    NASA Astrophysics Data System (ADS)

    Labelle, J. W.; Yan, X.; Pasternak, S.; Broughton, M.; Weatherwax, A. T.; Kojima, H.; Anderson, R. R.

    2014-12-01

    Following up initial observations of coincident ground-level AKR-like signals and outgoing AKR measured with the GEOTAIL satellite [LaBelle and Anderson, Geophys. Res. Lett., L04104, doi:10.1029/2010GL046411, 2011], investigation of 2008 data from four Antarctic observatories yields 37 additional examples. The occurrence rate of the ground-level AKR-like signals peaks near 22 UT similar to that of AKR. Because the distant satellite observes AKR from many sources, and because many effects can hinder transmission of AKR from the sources to either the distant satellite or the ground, a perfect correlation between ground-level AKR-like signals and outgoing AKR at GEOTAIL is not expected, and indeed correlation analysis of the ten longest-duration events suggests an imperfect correlation with 2-3 sigma significance, although at time much better correlations occur. Statistical analysis of the existing data is therefore suggestive but not does not prove a connection between the ground-level AKR-like signals and outgoing AKR. Two other methods provide strong evidence in favor of a connection between the phenomena, however. The first full-resolution measurements of ground-level AKR using a digital receiver at South Pole Station show that its fine structure closely resembles that of AKR measured by spacecraft receivers and is completely different from that of auroral hiss, the other auroral emission in the kilometric wavelength range. The digital receiver also determined the polarization of the AKR-like emissions to be right-hand, implying propagation in the whistler mode in the ionosphere. A weaker form of evidence comes from considering the locations of the ground station, satellite, and active aurora during coincident events. Two case studies suggest that the location of the active aurora, presumed connected with the AKR sources, controls whether or not the ground station detects the AKR, or which of several ground stations detects it most strongly. Taken together, these

  14. Gravitational radiation as radiation same level of electromagnetic and its generation in pulsed high-current discharge. Theory and experiment.

    NASA Astrophysics Data System (ADS)

    Fisenko, Stanislav; Fisenko, Igor

    2015-04-01

    The notion of gravitational radiation as a radiation of the same level as the electromagnetic radiation is based on theoretically proved and experimentally confirmed fact of existence of stationary states of an electron in its gravitational field characterized by the gravitational constant K = 1042 G (G is the Newtonian gravitational constant) and unrecoverable space-time curvature Λ. This paper gives an overview of the authors' works, which set out the relevant results. Additionally, data is provided on the broadening of the spectra characteristic radiation. The data show that this broadening can be explained only by the presence of excited states of electrons in their gravitational field. What is more, the interpretation of the new line of X-ray emission spectrum according to the results of observation of MOS-camera of XMM-Newton observatory is of interest. The given work contributes into further elaboration of the findings considering their application to dense high-temperature plasma of multiple-charge ions. This is due to quantitative character of electron gravitational radiation spectrum such that amplification of gravitational radiation may take place only in multiple-charge ion high-temperature plasma.

  15. Cosmic radiation in commercial aviation.

    PubMed

    Bagshaw, Michael

    2008-05-01

    This paper reviews the current knowledge of cosmic radiation and its applicability to commercial aviation. Galactic cosmic radiation emanates from outside the solar system, while occasionally a disturbance in the suns' atmosphere leads to a surge in radiation particles. Protection is provided by the suns' magnetic field, the earths' magnetic field, and the earths' atmosphere. Dose rates are dependent on the altitude, the geomagnetic latitude and the solar cycle. For occupational exposure to ionising radiation, which includes aircrew, the International Commission on Radiological Protection recommends maximum mean body effective dose limits of 20mSv/yr (averaged over 5 years, with a maximum in any 1 year of 50mSv). Radiation doses can be measured during flight or may be calculated using a computer-modelling program such as CARI, EPCARD, SIEVERT or PCAIRE. Mean ambient equivalent dose rates are consistently reported in the region of 4-5microSv/h for long-haul pilots and 1-3microSv/h for short-haul, giving an annual mean effective exposure of the order 2-3mSv for long-haul and 1-2mSv for short-haul pilots. Epidemiological studies of flight crew have not shown conclusive evidence for any increase in cancer mortality or cancer incidence directly attributable to ionising radiation exposure. Whilst there is no level of radiation exposure below which effects do not occur, current evidence indicates that the probability of airline crew or passengers suffering adverse health effects as a result of exposure to cosmic radiation is very low. PMID:18486066

  16. Skin dose measurements using radiochromic films, TLDS and ionisation chamber and comparison with Monte Carlo simulation.

    PubMed

    Alashrah, Saleh; Kandaiya, Sivamany; Maalej, Nabil; El-Taher, A

    2014-12-01

    Estimation of the surface dose is very important for patients undergoing radiation therapy. The purpose of this study is to investigate the dose at the surface of a water phantom at a depth of 0.007 cm as recommended by the International Commission on Radiological Protection and International Commission on Radiation Units and Measurement with radiochromic films (RFs), thermoluminescent dosemeters and an ionisation chamber in a 6-MV photon beam. The results were compared with the theoretical calculation using Monte Carlo (MC) simulation software (MCNP5, BEAMnrc and DOSXYZnrc). The RF was calibrated by placing the films at a depth of maximum dose (d(max)) in a solid water phantom and exposing it to doses from 0 to 500 cGy. The films were scanned using a transmission high-resolution HP scanner. The optical density of the film was obtained from the red component of the RGB images using ImageJ software. The per cent surface dose (PSD) and percentage depth dose (PDD) curve were obtained by placing film pieces at the surface and at different depths in the solid water phantom. TLDs were placed at a depth of 10 cm in a solid water phantom for calibration. Then the TLDs were placed at different depths in the water phantom and were exposed to obtain the PDD. The obtained PSD and PDD values were compared with those obtained using a cylindrical ionisation chamber. The PSD was also determined using Monte Carlo simulation of a LINAC 6-MV photon beam. The extrapolation method was used to determine the PSD for all measurements. The PSD was 15.0±3.6% for RF. The TLD measurement of the PSD was 16.0±5.0%. The (0.6 cm(3)) cylindrical ionisation chamber measurement of the PSD was 50.0±3.0%. The theoretical calculation using MCNP5 and DOSXYZnrc yielded a PSD of 15.0±2.0% and 15.7±2.2%. In this study, good agreement between PSD measurements was observed using RF and TLDs with the Monte Carlo calculation. However, the cylindrical chamber measurement yielded an overestimate of the PSD

  17. The effectiveness of photocatalytic ionisation disinfection of filter materials.

    PubMed

    Pietrzak, Katarzyna; Gutarowska, Beata

    2013-01-01

    The purpose of this study was to determine the effectiveness of photocatalytic ionisation as a disinfection method for filter materials contaminated by microorganisms, and to assess how air relative humidity (RH), time and microbe type influence the effectiveness of this disinfection. In the quantitative analysis of a used car air filter, bacterial contamination equalled 1.2 x 10(5) cfu/cm2, fungal contamination was 3.8 x 10(6) cfu/cm2, and the isolated microorganisms were Aspergillus niger, Bacillus megaterium, Cladosporium herbarum, Cryptococcus laurenti, Micrococcus sp., Rhodotorula glutinis and Staphylococcus cohnii. In the model experiment, three isolates (C. herbarum, R. glutinis, S. cohnii) and 3 ATCC species (A. niger, E. coli, S. aureus) were used for photocatalytic ionisation disinfection. The conditions of effective photocatalytic ionisation disinfection (R > or = 99.9%) were established as 2-3 h at RH = 77% (bacteria) and 6-24 h at RH = 53% (fungi). RH has an influence on the effectiveness of the photocatalytic disinfection process; the highest effectiveness was obtained for bacteria at RH = 77%, with results 5% higher than for RH = 49%. The studies show that the sensitivity of microorganisms to photocatalytic ionisation disinfection is ordered as follows: Gram-positive bacteria (S. cohnii, S. aureus), Gram-negative bacteria (E. coli), yeasts (R. glutinis), and moulds (C. herbarum, A. niger). Of all the mathematical models used for the description of death dynamics after photocatalytic ionisation disinfection, the Chick-Watson model is the most useful, but for more resistant microorganisms, the delayed Chick-Watson model is highly recommended. It therefore seems, that the presented disinfection method of photocatalytic ionisation can be successfully used to clean filtration materials. PMID:24053016

  18. Defining Top-of-Atmosphere Flux Reference Level for Earth Radiation Budget Studies

    NASA Technical Reports Server (NTRS)

    Loeb, N. G.; Kato, S.; Wielicki, B. A.

    2002-01-01

    To estimate the earth's radiation budget at the top of the atmosphere (TOA) from satellite-measured radiances, it is necessary to account for the finite geometry of the earth and recognize that the earth is a solid body surrounded by a translucent atmosphere of finite thickness that attenuates solar radiation differently at different heights. As a result, in order to account for all of the reflected solar and emitted thermal radiation from the planet by direct integration of satellite-measured radiances, the measurement viewing geometry must be defined at a reference level well above the earth s surface (e.g., 100 km). This ensures that all radiation contributions, including radiation escaping the planet along slant paths above the earth s tangent point, are accounted for. By using a field-of- view (FOV) reference level that is too low (such as the surface reference level), TOA fluxes for most scene types are systematically underestimated by 1-2 W/sq m. In addition, since TOA flux represents a flow of radiant energy per unit area, and varies with distance from the earth according to the inverse-square law, a reference level is also needed to define satellite-based TOA fluxes. From theoretical radiative transfer calculations using a model that accounts for spherical geometry, the optimal reference level for defining TOA fluxes in radiation budget studies for the earth is estimated to be approximately 20 km. At this reference level, there is no need to explicitly account for horizontal transmission of solar radiation through the atmosphere in the earth radiation budget calculation. In this context, therefore, the 20-km reference level corresponds to the effective radiative top of atmosphere for the planet. Although the optimal flux reference level depends slightly on scene type due to differences in effective transmission of solar radiation with cloud height, the difference in flux caused by neglecting the scene-type dependence is less than 0.1%. If an inappropriate

  19. X-33 XRS-2200 Linear Aerospike Engine Sea Level Plume Radiation

    NASA Technical Reports Server (NTRS)

    DAgostino, Mark G.; Lee, Young C.; Wang, Ten-See; Turner, Jim (Technical Monitor)

    2001-01-01

    Wide band plume radiation data were collected during ten sea level tests of a single XRS-2200 engine at the NASA Stennis Space Center in 1999 and 2000. The XRS-2200 is a liquid hydrogen/liquid oxygen fueled, gas generator cycle linear aerospike engine which develops 204,420 lbf thrust at sea level. Instrumentation consisted of six hemispherical radiometers and one narrow view radiometer. Test conditions varied from 100% to 57% power level (PL) and 6.0 to 4.5 oxidizer to fuel (O/F) ratio. Measured radiation rates generally increased with engine chamber pressure and mixture ratio. One hundred percent power level radiation data were compared to predictions made with the FDNS and GASRAD codes. Predicted levels ranged from 42% over to 7% under average test values.

  20. Measurement of natural radiative lifetime of excited levels of Tm atom

    SciTech Connect

    Wang Chengfei; Jiang Zhankui; Zhou Dafan; Liang Xiuqing

    1988-10-01

    The natural radiative lifetime of some low-lying excited levels in Tm atoms have been determined from measurements of time-resolved laser-induced fluorescence in atomic beam. The levels were selectively populated by the light from a pulsed tunable dye laser pumped by an excimer laser or a Nd:YAG laser.

  1. Potential for radiation damage to carbon steel storage tanks for high level radioactive waste

    SciTech Connect

    Caskey, G.R. Jr.; Sindelar, R.L.; Thomas, J.K.

    1993-07-30

    A low intensity radiation field is generated by the high level waste that is stored within carbon steel lined tanks at the Savannah River Site (SRS). The highest level of radiation damage to the tank walls from gamma and spontaneous neutron emissions is estimated to be less than 1.0E-6 displacements per atom (DPA) for a 100 year exposure to fresh, ``high heat`` SRS waste assuming continuous replenishment of the radionuclides. This damage level is below the limit for measurable radiation damage to the mechanical properties of carbon steel. Structural assessment of tanks for storage of high level waste may be based on nominal or code values of the mechanical properties of the steels from which the tanks were constructed.

  2. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    NASA Astrophysics Data System (ADS)

    Bero, M. A.; Abukassem, I.

    2009-05-01

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  3. Energy levels and radiative rates for Cr-like Cu VI and Zn VII

    NASA Astrophysics Data System (ADS)

    Aggarwal, K. M.; Bogdanovich, P.; Keenan, F. P.; Kisielius, R.

    2016-09-01

    Energy levels and radiative rates (A-values) for transitions in Cr-like Cu VI and Zn VII are reported. These data are determined in the quasi-relativistic approach (QR), by employing a very large configuration interaction (CI) expansion which is highly important for these ions. No radiative rates are available in the literature to compare with our results, but our calculated energies are in close agreement with those compiled by NIST and other available theoretical data, for a majority of the levels. The A-values (and resultant lifetimes) are listed for all significantly contributing E1, E2 and M1 radiative transitions among the energetically lowest 322 levels of each ion.

  4. 10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Reports § 20.2203 Reports of exposures, radiation levels, and concentrations...

  5. 10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... environmental radiation standards in 40 CFR part 190, levels of radiation or releases of radioactive material in... of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR..., radiation levels, and concentrations of radioactive material exceeding the constraints or limits....

  6. 10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... environmental radiation standards in 40 CFR part 190, levels of radiation or releases of radioactive material in... of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR..., radiation levels, and concentrations of radioactive material exceeding the constraints or limits....

  7. 10 CFR 20.2203 - Reports of exposures, radiation levels, and concentrations of radioactive material exceeding the...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... environmental radiation standards in 40 CFR part 190, levels of radiation or releases of radioactive material in... of radioactive material exceeding the constraints or limits. 20.2203 Section 20.2203 Energy NUCLEAR..., radiation levels, and concentrations of radioactive material exceeding the constraints or limits....

  8. Antihydrogen level population evolution: impact of positron plasma length

    NASA Astrophysics Data System (ADS)

    Radics, B.; Yamazaki, Y.

    2016-03-01

    Antihydrogen is produced by mixing an antiproton and a positron plasma in a cryogenic electromagnetic trap. The dominant antihydrogen formation mechanism is three-body recombination, while the subsequent level population evolution is governed by various processes, mainly collisional (de)excitation, ionisation and radiative decay. In this work the impact of various positron plasma lengths on the level population evolution is investigated. The main interest is the ground-state antihydrogen atom yield. It is found that the ground state level population shows different power-law behaviors at short or longer positron plasma lengths.

  9. Effect of radiation and age on immunoglobulin levels in rhesus monkeys (Macaca mulatta)

    NASA Technical Reports Server (NTRS)

    Stone, W. H.; Saphire, D. G.; Hackleman, S. M.; Braun, A. M.; Pennington, P.; Scheffler, J.; Wigle, J. C.; Cox, A. B.

    1994-01-01

    We report the results of a study on the immunoglobulin levels of rhesus monkeys (Macaca mulatta) in a colony consisting of the survivors of monkeys that received a single whole-body exposure to protons, electrons or X rays between 1964 and 1969. This colony has been maintained to assess the long-term effects of ionizing radiation on astronauts and high-flying pilots. Of the original 358 monkeys that were retained for lifetime studies, 129 (97 irradiated and 32 controls) were available for our study. We found no significant difference between the irradiated and control monkeys in mean levels of IgA, IgG and IgM, irrespective of the radiation treatment. The availability of these aged monkeys provided a unique opportunity to compare their immunoglobulin levels to those of other monkeys of various ages, and thus assess the effect of age on immunoglobulin levels. We found that only the IgA levels increase with age.

  10. Increased Artemis levels confer radioresistance to both high and low LET radiation exposures

    PubMed Central

    2012-01-01

    Background Artemis has a defined role in V(D)J recombination and has been implicated in the repair of radiation induced double-strand breaks. However the exact function(s) of Artemis in DNA repair and its preferred substrate(s) in vivo remain undefined. Our previous work suggests that Artemis is important for the repair of complex DNA damage like that inflicted by high Linear Energy Transfer (LET) radiation. To establish the contribution of Artemis in repairing DNA damage caused by various radiation qualities, we evaluated the effect of over-expressing Artemis on cell survival, DNA repair, and cell cycle arrest after exposure to high and low LET radiation. Results Our data reveal that Artemis over-expression confers marked radioprotection against both types of radiation, although the radioprotective effect was greater following high LET radiation. Inhibitor studies reveal that the radioprotection imparted by Artemis is primarily dependent on DNA-PK activity, and to a lesser extent on ATM kinase activity. Together, these data suggest a DNA-PK dependent role for Artemis in the repair of complex DNA damage. Conclusions These findings indicate that Artemis levels significantly influence radiation toxicity in human cells and suggest that Artemis inhibition could be a practical target for adjuvant cancer therapies. PMID:22713703

  11. Diffuse radiation increases global ecosystem-level water-use efficiency

    NASA Astrophysics Data System (ADS)

    Moffat, A. M.; Reichstein, M.; Cescatti, A.; Knohl, A.; Zaehle, S.

    2012-12-01

    Current environmental changes lead not only to rising atmospheric CO2 levels and air temperature but also to changes in air pollution and thus the light quality of the solar radiation reaching the land-surface. While rising CO2 levels are thought to enhance photosynthesis and closure of stomata, thus leading to relative water savings, the effect of diffuse radiation on transpiration by plants is less clear. It has been speculated that the stimulation of photosynthesis by increased levels of diffuse light may be counteracted by higher transpiration and consequently water depletion and drought stress. Ultimately, in water co-limited systems, the overall effect of diffuse radiation will depend on the sensitivity of canopy transpiration versus photosynthesis to diffuse light, i.e. whether water-use efficiency changes with relative levels of diffuse light. Our study shows that water-use efficiency increases significantly with higher fractions of diffuse light. It uses the ecosystem-atmosphere gas-exchange observations obtained with the eddy covariance method at 29 flux tower sites. In contrast to previous global studies, the analysis is based directly on measurements of diffuse radiation. Its effect on water-use efficiency was derived by analyzing the multivariate response of carbon and water fluxes to radiation and air humidity using a purely empirical approach based on artificial neural networks. We infer that per unit change of diffuse fraction the water-use efficiency increases up to 40% depending on diffuse fraction levels and ecosystem type. Hence, in regions with increasing diffuse radiation positive effects on primary production are expected even under conditions where water is co-limiting productivity.

  12. Economic impact and effectiveness of radiation protection measures in aviation during a ground level enhancement

    NASA Astrophysics Data System (ADS)

    Matthiä, Daniel; Schaefer, Martin; Meier, Matthias M.

    2015-06-01

    In addition to the omnipresent irradiation from galactic cosmic rays (GCR) and their secondary products, passengers and aircraft crew may be exposed to radiation from solar cosmic rays during ground level enhancements (GLE). In general, lowering the flight altitude and changing the flight route to lower latitudes are procedures applicable to immediately reduce the radiation exposure at aviation altitudes. In practice, however, taking such action necessarily leads to modifications in the flight plan and the consequential, additional fuel consumption constrains the mitigating measures. In this work we investigate in a case study of the ground level event of December 13th 2006 how potential mitigation procedures affect the total radiation exposure during a transatlantic flight from Seattle to Cologne taking into account constraints concerning fuel consumption and range.

  13. Sunlight-Exposed Biofilm Microbial Communities Are Naturally Resistant to Chernobyl Ionizing-Radiation Levels

    PubMed Central

    Ragon, Marie; Restoux, Gwendal; Moreira, David; Møller, Anders Pape; López-García, Purificación

    2011-01-01

    Background The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. Methodology/Principal Findings To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. Conclusions/Significance Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general

  14. Level Densities and Radiative Strength Functions in 56FE and 57FE

    SciTech Connect

    Tavukcu, E

    2002-12-10

    Understanding nuclear level densities and radiative strength functions is important for pure and applied nuclear physics. Recently, the Oslo Cyclotron Group has developed an experimental method to extract level densities and radiative strength functions simultaneously from the primary {gamma} rays after a light-ion reaction. A primary {gamma}-ray spectrum represents the {gamma}-decay probability distribution. The Oslo method is based on the Axel-Brink hypothesis, according to which the primary {gamma}-ray spectrum is proportional to the product of the level density at the final energy and the radiative strength function. The level density and the radiative strength function are fit to the experimental primary {gamma}-ray spectra, and then normalized to known data. The method works well for heavy nuclei. The present measurements extend the Oslo method to the lighter mass nuclei {sup 56}Fe and {sup 57}Fe. The experimental level densities in {sup 56}Fe and {sup 57}Fe reveal step structure. This step structure is a signature for nucleon pair breaking. The predicted pairing gap parameter is in good agreement with the step corresponding to the first pair breaking. Thermodynamic quantities for {sup 56}Fe and {sup 57}Fe are derived within the microcanonical and canonical ensembles using the experimental level densities. Energy-temperature relations are considered using caloric curves and probability density functions. The differences between the thermodynamics of small and large systems are emphasized. The experimental heat capacities are compared with the recent theoretical calculations obtained in the Shell Model Monte Carlo method. Radiative strength functions in {sup 56}Fe and {sup 57}Fe have surprisingly high values at low {gamma}-ray energies. This behavior has not been observed for heavy nuclei, but has been observed in other light- and medium-mass nuclei. The origin of this low {gamma}-ray energy effect remains unknown.

  15. Level densities and radiative strength functions in ^116,117Sn

    NASA Astrophysics Data System (ADS)

    Agvaanluvsan, U.; Mitchell, G. E.; Chankova, R.; Guttormsen, M.; Sunde, A.-C.; Becker, J. A.; Bernstein, L. A.; Schiller, A.; Voinov, A.

    2003-10-01

    Level densities and radiative strength functions are important for understanding nuclear properties in general, for an accurate knowledge of nuclear reaction rates in particular. A recently developed method to extract level densities and radiative strength functions from ^3He induced reactions is applied to ^117Sn. Level densities and radiative strength functions in ^116,117Sn from ground state up to the neutron binding energy are obtained from ^3He and α channels. Spectra of the first γ-rays emitted from each excitation energy bin are obtained via sequential extraction. The emission probability of these γ-rays is proportional to the product of the radiative strength function and the final state level density. This so-called Oslo method has been applied extensively to rare-earth nuclei. The method has also been applied to lighter nuclei such as Fe and Mo. The measurement of ^116,117Sn is intended to provide information on nuclei intermediate between the lighter and heavier nuclei that show quite different behavior.

  16. Determining the Knowledge Level of Pre-Service Teachers' on Radioactivity and Radiation

    ERIC Educational Resources Information Center

    Ergul, N. Remziye

    2012-01-01

    This study investigated the basic knowledge levels of teacher candidates' from different branches regarding the subjects of radiation and radioactivity. 42 variables were determined in relation to the specified titles. In the preparation stage of determining the variables, all the related programs were examined, and attention was paid to include…

  17. Determining the Knowledge Level of Pre-Service Teachers' on Radioactivity and Radiation

    ERIC Educational Resources Information Center

    Ergul, N. Remziye

    2012-01-01

    This study investigated the basic knowledge levels of teacher candidates from different branches regarding the subjects of radiation and radioactivity. 42 variables were determined in relation to the specified titles. In the preparation stage of determining the variables, all the related programs were examined, and attention was paid to include…

  18. NATIONAL- AND STATE-LEVEL EMISSIONS ESTIMATES OF RADIATIVELY IMPORTANT TRACE GASES (RITGS) FROM ANTHROPOGENIC SOURCES

    EPA Science Inventory

    The report documents the development of national- and state- level emissions estimates of radiatively important trace gases (RlTGs). Emissions estimates are presented for the principal anthropogenic sources of carbon dioxide (CO2), methane (CH4), chlorofluorocarbons (CFCs), and o...

  19. 41 CFR 50-204.35 - Application for variations from radiation levels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Application for variations from radiation levels. 50-204.35 Section 50-204.35 Public Contracts and Property Management Other Provisions Relating to Public Contracts PUBLIC CONTRACTS, DEPARTMENT OF LABOR 204-SAFETY AND HEALTH STANDARDS FOR FEDERAL SUPPLY CONTRACTS...

  20. 49 CFR 173.441 - Radiation level limitations and exclusive use provisions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Radiation level limitations and exclusive use provisions. 173.441 Section 173.441 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS...

  1. 41 CFR 50-204.35 - Application for variations from radiation levels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Provisions Relating to Public Contracts PUBLIC CONTRACTS, DEPARTMENT OF LABOR 204-SAFETY AND HEALTH STANDARDS... levels. (a) In accordance with policy expressed in the Federal Radiation Council's memorandum concerning... undue hazard, and (4) appropriate actions will be taken to protect the health and safety of...

  2. 41 CFR 50-204.35 - Application for variations from radiation levels.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Provisions Relating to Public Contracts PUBLIC CONTRACTS, DEPARTMENT OF LABOR 204-SAFETY AND HEALTH STANDARDS... levels. (a) In accordance with policy expressed in the Federal Radiation Council's memorandum concerning... undue hazard, and (4) appropriate actions will be taken to protect the health and safety of...

  3. 41 CFR 50-204.35 - Application for variations from radiation levels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Provisions Relating to Public Contracts PUBLIC CONTRACTS, DEPARTMENT OF LABOR 204-SAFETY AND HEALTH STANDARDS... levels. (a) In accordance with policy expressed in the Federal Radiation Council's memorandum concerning... undue hazard, and (4) appropriate actions will be taken to protect the health and safety of...

  4. Cross-polarization level in radiation from a microstrip dipole antenna

    NASA Astrophysics Data System (ADS)

    Hoorfar, Ahmad; Gupta, Kuldip C.; Chang, David C.

    1988-09-01

    A description is given of the cross-polarization level in radiation from a small horizontal electric dipole (HED) on a flat grounded dielectric substrate. The study is directed toward the design of a very low cross-polarization level in a linear array of microstrip antenna elements. Field expressions for a copolarized and crosspolarized microstrip HED for any arbitrary dipole orientation and array direction are derived.

  5. High ionisation absorption in low mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ponti, G.; Bianchi, S.; Muñoz-Darias, T.; De, K.; Fender, R.; Merloni, A.

    2016-05-01

    The advent of the new generation of X-ray telescopes yielded a significant step forward in our understanding of ionised absorption generated in the accretion discs of X-ray binaries. It has become evident that these relatively weak and narrow absorption features, sporadically present in the X-ray spectra of some systems, are actually the signature of equatorial outflows, which might carry away more matter than that being accreted. Therefore, they play a major role in the accretion phenomenon. These outflows (or ionised atmospheres) are ubiquitous during the softer states but absent during the power-law dominated, hard states, suggesting a strong link with the state of the inner accretion disc, presence of the radio-jet and the properties of the central source. Here, we discuss the current understanding of this field.

  6. Airborne laser-spark for ambient desorption/ionisation.

    PubMed

    Bierstedt, Andreas; Riedel, Jens

    2016-01-01

    A novel direct sampling ionisation scheme for ambient mass spectrometry is presented. Desorption and ionisation are achieved by a quasi-continuous laser induced plasma in air. Since there are no solid or liquid electrodes involved the ion source does not suffer from chemical interferences or fatigue originating from erosive burning or from electrode consumption. The overall plasma maintains electro-neutrality, minimising charge effects and accompanying long term drift of the charged particles trajectories. In the airborne plasma approach the ambient air not only serves as the plasma medium but at the same time also slows down the nascent ions via collisional cooling. Ionisation of the analyte molecules does not occur in the plasma itself but is induced by interaction with nascent ionic fragments, electrons and/or far ultraviolet photons in the plasma vicinity. At each individual air-spark an audible shockwave is formed, providing new reactive species, which expands concentrically and, thus, prevents direct contact of the analyte with the hot region inside the plasma itself. As a consequence the interaction volume between plasma and analyte does not exceed the threshold temperature for thermal dissociation or fragmentation. Experimentally this indirect ionisation scheme is demonstrated to be widely unspecific to the chemical nature of the analyte and to hardly result in any fragmentation of the studied molecules. A vast ensemble of different test analytes including polar and non-polar hydrocarbons, sugars, low mass active ingredients of pharmaceuticals as well as natural biomolecules in food samples directly out of their complex matrices could be shown to yield easily accessible yet meaningful spectra. Since the plasma medium is humid air, the chemical reaction mechanism of the ionisation is likely to be similar to other ambient ionisation techniques. Wir stellen hier eine neue Ionisationsmethode für die Umgebungsionisation (ambient ionisation) vor. Sowohl die

  7. Ionisation of a quantum dot by electric fields

    SciTech Connect

    Eminov, P A; Gordeeva, S V

    2012-08-31

    We have derived analytical formulas for differential and total ionisation probabilities of a two-dimensional quantum dot by a constant electric field. In the adiabatic approximation, we have calculated the probability of this process in the field of a plane electromagnetic wave and in a superposition of constant and alternating electric fields. The imaginary-time method is used to obtain the momentum distribution of the ionisation probability of a bound system by an intense field generated by a superposition of parallel constant and alternating electric fields. The total probability of the process per unit time is calculated with exponential accuracy. The dependence of the results obtained on the characteristic parameters of the problem is investigated. (laser applications and other topics in quantum electronics)

  8. Wedge Absorber Design for the Muon Ionisation Cooling Experiment

    SciTech Connect

    Rogers, C.; Snopok, P.; Coney, L.; Jansson, A.; /Fermilab

    2010-05-01

    In the Muon Ionisation Cooling Experiment (MICE), muons are cooled by ionisation cooling. Muons are passed through material, reducing the total momentum of the beam. This results in a decrease in transverse emittance and a slight increase in longitudinal emittance, but overall reduction of 6d beam emittance. In emittance exchange, a dispersive beam is passed through wedge-shaped absorbers. Muons with higher energy pass through more material, resulting in a reduction in longitudinal emittance as well as transverse emittance. We consider the cooling performance of different wedge materials and geometries and propose a set of measurements that would be made in MICE.We outline the resources these measurements would require and detail some constraints that guide the choice of wedge parameters.

  9. Nrf2 sensitizes prostate cancer cells to radiation via decreasing basal ROS levels.

    PubMed

    Liu, Min; Yao, Xu-Dong; Li, Wei; Geng, Jiang; Yan, Yang; Che, Jian-Ping; Xu, Yun-Fei; Zheng, Jun-Hua

    2015-01-01

    Androgen deprivation therapy (ADT) was reported to lower basal ROS level in prostate cancer (PCa) and to sensitize PCa to radiation. We aimed to seek for the underlying molecular mechanism and to develop novel additive treatments to ADT in this regard. We simulated human androgen milieu in vitro and tested the ROS level in PCa cells undergoing ADT. We also tested the Nrf2 level in PCa cells with or without ADT. Genetic and pharmaceutical upregulation of Nrf2 was applied in vitro and in vivo in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice with or without castration to investigate whether Nrf2 overexpression supplemented the effect of ADT in PCa. We first discovered that androgen deprivation increased basal ROS level in PCa cells with AR expression. We then found that genetic Nrf2 upregulation lowered basal ROS similar to ADT. Also, SFN sensitized PCa cell to radiation via upregulation of Nrf2. We then found that Nrf2 level in control TRAMP groups was lower than castration or SFN groups. The SFN treated TRAMP mice showed similar level of Nrf2 to castration. Genetic and pharmaceutical upregulation of Nrf2 lowered the ROS in PCa cells and sensitized PCa cells to radiation similar to ADT, implicating possible administration of SFN in place of ADT for PCa patients requiring radiotherapy. PMID:25728635

  10. Effect of moderate level x-radiation to brain on cerebral glucose utilization

    SciTech Connect

    Ito, M.; Patronas, N.J.; Di Chiro, G.; Mansi, L.; Kennedy, C.

    1986-07-01

    The effect of x-radiation in doses used in treatment of brain malignancies has previously been established largely by histologic examination of the tissue or by observation of a deficit in function. At moderate dose levels such effects are usually delayed and are vascular in origin. We have used the 2-(/sup 14/C)deoxyglucose method for the quantitative measurement of local cerebral glucose utilization to learn whether x-radiation administered to rat brain in a dose below that which is known to result in any histologic change may nevertheless affect the brain's local rates of glucose utilization. Measurements were made 4 days and 4 weeks after exposure of groups of rats to 1500 rad. Rates of glucose utilization in 54 gray and eight white matter structures in both groups were compared with rates in sham-irradiated controls. Statistically significantly lower rates were found in 16 structures in rats 4 days after radiation and in 25 structures 4 weeks after radiation exposure. A weighted average rate for the brain as a whole was approximately 15% below that of the controls for both radiated groups, but this difference was short of being of statistical significance. It is clear from this study that the metabolic rates of some brain structures are reduced following moderate doses of x-radiation.

  11. Autocorrelation in ultraviolet radiation measured at ground level using detrended fluctuation analysis

    NASA Astrophysics Data System (ADS)

    da Silva Filho, Paulo Cavalcante; da Silva, Francisco Raimundo; Corso, Gilberto

    2016-07-01

    In this study, we analyzed the autocorrelation among four ultraviolet (UV) radiation data sets obtained at 305 nm, 320 nm, 340 nm, and 380 nm. The data were recorded at ground level at the INPE climate station in Natal, RN, Brazil, which is a site close to the equator. The autocorrelations were computed by detrended fluctuation analysis (DFA) to estimate the index α. We found that the ​fluctuations in the UV radiation data were fractal, with scale-free behavior at a DFA index α ≃ 0.7. In addition, we performed a power law spectral analysis, which showed that the power spectrum exhibited a power law behavior with an exponent of β ≃ 0.45. Given that the theoretical result is β = 2 α - 1, these two results are in good agreement. Moreover, the application of the DFA ​method to the UV radiation data required detrending using a polynomial with an order of at least eight, which was related to the complex daily solar radiation curve obtained at ground level in a tropical region. The results indicated that the α exponent of UV radiation is similar to other climatic records such as air temperature, wind, or rain, but not solar activity.

  12. Lower prevalence but similar fitness in a parasitic fungus at higher radiation levels near Chernobyl.

    PubMed

    Aguileta, Gabriela; Badouin, Helene; Hood, Michael E; Møller, Anders P; Le Prieur, Stephanie; Snirc, Alodie; Siguenza, Sophie; Mousseau, Timothy A; Shykoff, Jacqui A; Cuomo, Christina A; Giraud, Tatiana

    2016-07-01

    Nuclear disasters at Chernobyl and Fukushima provide examples of effects of acute ionizing radiation on mutations that can affect the fitness and distribution of species. Here, we investigated the prevalence of Microbotryum lychnidis-dioicae, a pollinator-transmitted fungal pathogen of plants causing anther-smut disease in Chernobyl, its viability, fertility and karyotype variation, and the accumulation of nonsynonymous mutations in its genome. We collected diseased flowers of Silene latifolia from locations ranging by more than two orders of magnitude in background radiation, from 0.05 to 21.03 μGy/h. Disease prevalence decreased significantly with increasing radiation level, possibly due to lower pollinator abundance and altered pollinator behaviour. Viability and fertility, measured as the budding rate of haploid sporidia following meiosis from the diploid teliospores, did not vary with increasing radiation levels and neither did karyotype overall structure and level of chromosomal size heterozygosity. We sequenced the genomes of twelve samples from Chernobyl and of four samples collected from uncontaminated areas and analysed alignments of 6068 predicted genes, corresponding to 1.04 × 10(7)  base pairs. We found no dose-dependent differences in substitution rates (neither dN, dS, nor dN/dS). Thus, we found no significant evidence of increased deleterious mutation rates at higher levels of background radiation in this plant pathogen. We even found lower levels of nonsynonymous substitution rates in contaminated areas compared to control regions, suggesting that purifying selection was stronger in contaminated than uncontaminated areas. We briefly discuss the possibilities for a mechanistic basis of radio resistance in this nonmelanized fungus. PMID:27136128

  13. Level of radiation dose in university hospital noninsured private health screening programs in Korea

    PubMed Central

    2016-01-01

    Objectives The aim of this study is to evaluate radiation exposure resulting from the comprehensive health examinations of selected university hospital programs and to present basic data for research and management strategies on the health effects of medical radiation exposure. Methods Radiation-based diagnostic studies of the comprehensive health examination programs of ten university hospitals in Seoul, Korea, as introduced in their websites, were analyzed. The medical radiation studies of the programs were reviewed by radiologists. Only the effective doses of the basic studies were included in the analysis. The optional studies of the programs were excluded. Results Among the 190 comprehensive health examination programs, 132 programs (69.5%) included computed tomography studies, with an average of 1.4 scans. The average effective dose of radiation by program was 3.62 mSv for an intensive program for specific diseases; 11.12 mSv for an intensive program for cancer; 18.14 mSv for a premium program; and 24.08 mSv for an overnight program. A higher cost of a programs was linked to a higher effective dose (r=0.812). The effective doses of the examination programs for the same purposes differed by as much as 2.1 times by hospital. Inclusion of positron emission tomography–computed tomography was the most critical factor in determining the level of effective dose. Conclusions It was found that radiation exposure dose from comprehensive health exam programs targeted for an asymptomatic, healthy public reached between 3.6 and 24 times the annual dose limit for the general public. Relevant management policies at the national level should be provided to minimize medical radiation exposure. PMID:27032387

  14. Erich Regener and the ionisation maximum of the atmosphere

    NASA Astrophysics Data System (ADS)

    Carlson, P.; Watson, A. A.

    2014-12-01

    In the 1930s the German physicist Erich Regener (1881-1955) did important work on the measurement of the rate of production of ionisation deep under water and in the atmosphere. Along with one of his students, Georg Pfotzer, he discovered the altitude at which the production of ionisation in the atmosphere reaches a maximum, often, but misleadingly, called the Pfotzer maximum. Regener was one of the first to estimate the energy density of cosmic rays, an estimate that was used by Baade and Zwicky to bolster their postulate that supernovae might be their source. Yet Regener's name is less recognised by present-day cosmic ray physicists than it should be, largely because in 1937 he was forced to take early retirement by the National Socialists as his wife had Jewish ancestors. In this paper we briefly review his work on cosmic rays and recommend an alternative naming of the ionisation maximum. The influence that Regener had on the field through his son, his son-in-law, his grandsons and his students, and through his links with Rutherford's group in Cambridge, is discussed in an appendix. Regener was nominated for the Nobel Prize in Physics by Schrödinger in 1938. He died in 1955 at the age of 73.

  15. Revisiting radiative deep-level transitions in CuGaSe2 by photoluminescence

    NASA Astrophysics Data System (ADS)

    Spindler, Conrad; Regesch, David; Siebentritt, Susanne

    2016-07-01

    Recent defect calculations suggest that the open circuit voltage of CuGaSe2 solar cells can be limited by deep intrinsic electron traps by GaCu antisites and their complexes with Cu-vacancies. To gain experimental evidence, two radiative defect transitions at 1.10 eV and 1.24 eV are characterized by steady-state photoluminescence on epitaxial-grown CuGaSe2 thin films. Cu-rich samples are studied, since they show highest crystal quality, exciton luminescence, and no potential fluctuations. Variations of the laser intensity and temperature dependent measurements suggest that emission occurs from two deep donor-like levels into the same shallow acceptor. At 10 K, power-law exponents of 1 (low excitation regime) and 1/2 (high excitation regime) are observed identically for both transitions. The theory and a fitting function for the double power law is derived. It is concluded that the acceptor becomes saturated by excess carriers which changes the exponent of all transitions. Activation energies determined from the temperature quenching depend on the excitation level and show unexpected values of 600 meV and higher. The thermal activation of non-radiative processes can explain the distortion of the ionization energies. Both the deep levels play a major role as radiative and non-radiative recombination centers for electrons and can be detrimental for photovoltaic applications.

  16. Energy levels and radiative rates for transitions in Cr-like Co IV and Ni V

    NASA Astrophysics Data System (ADS)

    Aggarwal, K. M.; Bogdanovich, P.; Karpuškienė, R.; Keenan, F. P.; Kisielius, R.; Stancalie, V.

    2016-01-01

    We report calculations of energy levels and radiative rates (A-values) for transitions in Cr-like Co IV and Ni V. The quasi-relativistic Hartree-Fock (QRHF) code is adopted for calculating the data although GRASP (general-purpose relativistic atomic structure package) and flexible atomic code (FAC) have also been employed for comparison purposes. No radiative rates are available in the literature to compare with our results, but our calculated energies are in close agreement with those compiled by NIST for a majority of the levels. However, there are discrepancies for a few levels of up to 3%. The A-values are listed for all significantly contributing E1, E2 and M1 transitions, and the corresponding lifetimes reported, although unfortunately no previous theoretical or experimental results exist to compare with our data.

  17. Low-level red laser therapy alters effects of ultraviolet C radiation on Escherichia coli cells.

    PubMed

    Canuto, K S; Sergio, L P S; Guimarães, O R; Geller, M; Paoli, F; Fonseca, A S

    2015-10-01

    Low-level lasers are used at low power densities and doses according to clinical protocols supplied with laser devices or based on professional practice. Although use of these lasers is increasing in many countries, the molecular mechanisms involved in effects of low-level lasers, mainly on DNA, are controversial. In this study, we evaluated the effects of low-level red lasers on survival, filamentation, and morphology of Escherichia colicells that were exposed to ultraviolet C (UVC) radiation. Exponential and stationary wild-type and uvrA-deficientE. coli cells were exposed to a low-level red laser and in sequence to UVC radiation. Bacterial survival was evaluated to determine the laser protection factor (ratio between the number of viable cells after exposure to the red laser and UVC and the number of viable cells after exposure to UVC). Bacterial filaments were counted to obtain the percentage of filamentation. Area-perimeter ratios were calculated for evaluation of cellular morphology. Experiments were carried out in duplicate and the results are reported as the means of three independent assays. Pre-exposure to a red laser protected wild-type and uvrA-deficient E. coli cells against the lethal effect of UVC radiation, and increased the percentage of filamentation and the area-perimeter ratio, depending on UVC fluence and physiological conditions in the cells. Therapeutic, low-level red laser radiation can induce DNA lesions at a sub-lethal level. Consequences to cells and tissues should be considered when clinical protocols based on this laser are carried out. PMID:26445338

  18. Low-level red laser therapy alters effects of ultraviolet C radiation on Escherichia coli cells

    PubMed Central

    Canuto, K.S.; Sergio, L.P.S.; Guimarães, O.R.; Geller, M.; Paoli, F.; Fonseca, A.S.

    2015-01-01

    Low-level lasers are used at low power densities and doses according to clinical protocols supplied with laser devices or based on professional practice. Although use of these lasers is increasing in many countries, the molecular mechanisms involved in effects of low-level lasers, mainly on DNA, are controversial. In this study, we evaluated the effects of low-level red lasers on survival, filamentation, and morphology of Escherichia colicells that were exposed to ultraviolet C (UVC) radiation. Exponential and stationary wild-type and uvrA-deficientE. coli cells were exposed to a low-level red laser and in sequence to UVC radiation. Bacterial survival was evaluated to determine the laser protection factor (ratio between the number of viable cells after exposure to the red laser and UVC and the number of viable cells after exposure to UVC). Bacterial filaments were counted to obtain the percentage of filamentation. Area-perimeter ratios were calculated for evaluation of cellular morphology. Experiments were carried out in duplicate and the results are reported as the means of three independent assays. Pre-exposure to a red laser protected wild-type and uvrA-deficient E. coli cells against the lethal effect of UVC radiation, and increased the percentage of filamentation and the area-perimeter ratio, depending on UVC fluence and physiological conditions in the cells. Therapeutic, low-level red laser radiation can induce DNA lesions at a sub-lethal level. Consequences to cells and tissues should be considered when clinical protocols based on this laser are carried out. PMID:26445338

  19. Assessing risks from occupational exposure to low-level radiation: The statistician's role

    SciTech Connect

    Gilbert, E.S.

    1989-06-01

    Currently, several epidemiological studies of workers who have been exposed occupationally to radiation are being conducted. These include workers in the United States, Great Britain, and Canada, involved in the production of both defense materials and nuclear power. A major reason for conducting these studies is to evaluate possible adverse health effects that may have resulted because of the radiation exposure received. The general subject of health effects resulting from low levels of radiation, including these worker studies, has attracted the attention of various news media, and has been the subject of considerable controversy. These studies provide a good illustration of certain other aspects of the statistician's role; namely, communication and adequate subject matter knowledge. A competent technical job is not sufficient if these other aspects are not fulfilled.

  20. A Colorimetric Plasmonic Nanosensor for Dosimetry of Therapeutic Levels of Ionizing Radiation.

    PubMed

    Pushpavanam, Karthik; Narayanan, Eshwaran; Chang, John; Sapareto, Stephen; Rege, Kaushal

    2015-12-22

    Modern radiation therapy using highly automated linear accelerators is a complex process that maximizes doses to tumors and minimizes incident dose to normal tissues. Dosimeters can help determine the radiation dose delivered to target diseased tissue while minimizing damage to surrounding healthy tissue. However, existing dosimeters can be complex to fabricate, expensive, and cumbersome to operate. Here, we demonstrate studies of a liquid phase, visually evaluated plasmonic nanosensor that detects radiation doses commonly employed in fractionated radiotherapy (1-10 Gy) for tumor ablation. We accomplished this by employing ionizing radiation, in concert with templating lipid surfactant micelles, in order to convert colorless salt solutions of univalent gold ions (Au(1)) to maroon-colored dispersions of plasmonic gold nanoparticles. Differences in color intensities of nanoparticle dispersions were employed as quantitative indicators of the radiation dose. The nanoparticles thus formed were characterized using UV-vis absorbance spectroscopy, dynamic light scattering, and transmission electron microscopy. The role of lipid surfactants on nanoparticle formation was investigated by varying the chain lengths while maintaining the same headgroup and counterion; the effect of surfactant concentration on detection efficacy was also investigated. The plasmonic nanosensor was able to detect doses as low as 0.5 Gy and demonstrated a linear detection range of 0.5-2 Gy or 5-37 Gy depending on the concentration of the lipid surfactant employed. The plasmonic nanosensor was also able to detect radiation levels in anthropomorphic prostate phantoms when administered together with endorectal balloons, indicating its potential utility as a dosimeter in fractionated radiotherapy for prostate cancer. Taken together, our results indicate that this simple visible nanosensor has strong potential to be used as a dosimeter for validating delivered radiation doses in fractionated

  1. Energy levels, radiative rates, and lifetimes for transitions in W LVIII

    SciTech Connect

    Aggarwal, Kanti M. Keenan, Francis P.

    2014-11-15

    Energy levels and radiative rates are reported for transitions in Cl-like W LVIII. Configuration interaction (CI) has been included among 44 configurations (generating 4978 levels) over a wide energy range up to 363 Ryd, and the general-purpose relativistic atomic structure package (GRASP) adopted for the calculations. Since no other results of comparable complexity are available, calculations have also been performed with the flexible atomic code (FAC), which help in assessing the accuracy of our results. Energies are listed for the lowest 400 levels (with energies up to ∼98 Ryd), which mainly belong to the 3s{sup 2}3p{sup 5}, 3s3p{sup 6}, 3s{sup 2}3p{sup 4}3d, 3s{sup 2}3p{sup 3}3d{sup 2}, 3s3p{sup 4}3d{sup 2}, 3s{sup 2}3p{sup 2}3d{sup 3}, and 3p{sup 6}3d configurations, and radiative rates are provided for four types of transitions, i.e. E1, E2, M1, and M2. Our energy levels are assessed to be accurate to better than 0.5%, whereas radiative rates (and lifetimes) should be accurate to better than 20% for a majority of the strong transitions.

  2. Energy levels, radiative rates, and lifetimes for transitions in W LVIII

    NASA Astrophysics Data System (ADS)

    Aggarwal, Kanti M.; Keenan, Francis P.

    2014-11-01

    Energy levels and radiative rates are reported for transitions in Cl-like W LVIII. Configuration interaction (CI) has been included among 44 configurations (generating 4978 levels) over a wide energy range up to 363 Ryd, and the general-purpose relativistic atomic structure package (GRASP) adopted for the calculations. Since no other results of comparable complexity are available, calculations have also been performed with the flexible atomic code (FAC), which help in assessing the accuracy of our results. Energies are listed for the lowest 400 levels (with energies up to ˜98 Ryd), which mainly belong to the 3s23p5, 3s3p6, 3s23p43d, 3s23p33d2, 3s3p43d2, 3s23p23d3, and 3p63d configurations, and radiative rates are provided for four types of transitions, i.e. E1, E2, M1, and M2. Our energy levels are assessed to be accurate to better than 0.5%, whereas radiative rates (and lifetimes) should be accurate to better than 20% for a majority of the strong transitions.

  3. Recommended Radiation Protection Practices for Low-Level Waste Disposal Sites

    SciTech Connect

    Hadlock, D. E.; Hooker, C. D.; Herrington, W. N.; Gilchrist, R. L.

    1983-12-01

    The United States Nuclear Regulatory Commission contracted with Pacific Northwest Laboratory (PNL) to provide technical assistance in estsblishing operational guidelines, with respect to radiation control programs and methods of minimizing occupational radiation exposure, at Low-Level Waste (LLW) dis- posal sites. The PNL, through site visits, evaluated operations at LLW dis- posal sites to determine the adequacy of current practices in maintaining occupational exposures as low as is reasonably achievable (ALARA). The data sought included the specifics of: ALARA programs, training programs, external exposure control , internal exposure control , respiratory protection, survei 1 - lance, radioactive waste management, facilities and equipment, and external dose analysis. The results of the study indicated the following: The Radiation Protection and ALARA programs at the three commercial LLW disposal sites were observed to be adequate in scope and content compared to similar programs at other types of nuclear facilities. However, it should be noted that there were many areas that could be improved upon to help ensure the health and safety of the occupa- tionally exposed individuals. As a result, radiation protection practices were recommended with related rationales in order to reduce occupational exposures as far below specified radiation limits as is reasonably achievable. In addition, recommendations were developed for achieving occupational exposure ALARA under the Regulatory Requirements issued in 10 CFR Part 61.

  4. Electron impact ionisation cross sections for atomic and molecular allotropes of phosphorous and arsenic

    NASA Astrophysics Data System (ADS)

    Bhutadia, Harshad; Chaudhari, Ashok; Vinodkumar, Minaxi

    2015-12-01

    We report electron impact total ionisation cross sections for phosphorous (P), arsenic (As), diphosphorous (P2), diarsenic (As2), tetra phosphorous (P4) and tetra arsenic (As4) from the threshold of the target to 2000 eV. We employed spherical complex optical potential to compute total inelastic cross sections (Qinel). The total ionisation cross section is extracted from the total inelastic cross section using the complex scattering potential-ionisation contribution method. The results of most of the targets studied here compare well with the measurements and the theoretical data wherever available. The correlation between the peak of ionisation cross sections with the number of target electrons and polarisability is also reported. It is observed that the maximum ionisation cross sections depend linearly on the number of target electrons and polarisability of the target. This linear correlation is used to predict the maximum ionisation cross sections for the targets (I2, HI and PF3) where no experimental data are available.

  5. Ultraviolet B radiation was increased at ground level in scotland during a period of ozone depletion.

    PubMed

    Moseley, H; Mackie, R M

    1997-07-01

    The potentially harmful effects associated with stratospheric ozone depletion are widely acknowledged. As the ozone layer principally absorbs ultraviolet (UV) radiation of wavelengths below 290 nm, reductions in stratospheric ozone levels are likely to result in increased UVB at the earth's surface, with the risk of increased incidence of skin cancer. Measuring the sun's spectrum at ground level requires sophisticated and reliable spectral instruments. Results are reported for this for the first time in the U.K. using spectral instruments, showing a significant increase in short wavelength UV radiation at a time of depleted stratospheric ozone. If this trend increases, future ozone depletion could contribute to known risks for cutaneous malignancies of all types. PMID:9274633

  6. Estimation of Radiofrequency Power Leakage from Microwave Ovens for Dosimetric Assessment at Nonionizing Radiation Exposure Levels

    PubMed Central

    Lopez-Iturri, Peio; de Miguel-Bilbao, Silvia; Aguirre, Erik; Azpilicueta, Leire; Falcone, Francisco; Ramos, Victoria

    2015-01-01

    The electromagnetic field leakage levels of nonionizing radiation from a microwave oven have been estimated within a complex indoor scenario. By employing a hybrid simulation technique, based on coupling full wave simulation with an in-house developed deterministic 3D ray launching code, estimations of the observed electric field values can be obtained for the complete indoor scenario. The microwave oven can be modeled as a time- and frequency-dependent radiating source, in which leakage, basically from the microwave oven door, is propagated along the complete indoor scenario interacting with all of the elements present in it. This method can be of aid in order to assess the impact of such devices on expected exposure levels, allowing adequate minimization strategies such as optimal location to be applied. PMID:25705676

  7. Estimation of radiofrequency power leakage from microwave ovens for dosimetric assessment at nonionizing radiation exposure levels.

    PubMed

    Lopez-Iturri, Peio; de Miguel-Bilbao, Silvia; Aguirre, Erik; Azpilicueta, Leire; Falcone, Francisco; Ramos, Victoria

    2015-01-01

    The electromagnetic field leakage levels of nonionizing radiation from a microwave oven have been estimated within a complex indoor scenario. By employing a hybrid simulation technique, based on coupling full wave simulation with an in-house developed deterministic 3D ray launching code, estimations of the observed electric field values can be obtained for the complete indoor scenario. The microwave oven can be modeled as a time- and frequency-dependent radiating source, in which leakage, basically from the microwave oven door, is propagated along the complete indoor scenario interacting with all of the elements present in it. This method can be of aid in order to assess the impact of such devices on expected exposure levels, allowing adequate minimization strategies such as optimal location to be applied. PMID:25705676

  8. Tension between reducing sea-level rise and global warming through solar-radiation management

    NASA Astrophysics Data System (ADS)

    Irvine, P. J.; Sriver, R. L.; Keller, K.

    2012-02-01

    Geoengineering using solar-radiation management (SRM) is gaining interest as a potential strategy to reduce future climate change impacts. Basic physics and past observations suggest that reducing insolation will, on average, cool the Earth. It is uncertain, however, whether SRM can reduce climate change stressors such as sea-level rise or rates of surface air temperature change. Here we use an Earth system model of intermediate complexity to quantify the possible response of sea levels and surface air temperatures to projected climate forcings and SRM strategies. We find that SRM strategies introduce a potentially strong tension between the objectives to reduce (1) the rate of temperature change and (2) sea-level rise. This tension arises primarily because surface air temperatures respond faster to radiative forcings than sea levels. Our results show that the forcing required to stop sea-level rise could cause a rapid cooling with a rate similar to the peak business-as-usual warming rate. Furthermore, termination of SRM was found to produce warming rates up to five times greater than the maximum rates under the business-as-usual CO2 scenario, whereas sea-level rise rates were only 30% higher. Reducing these risks requires a slow phase-out of many decades and thus commits future generations.

  9. Aerosols attenuating the solar radiation collected by solar tower plants: The horizontal pathway at surface level

    NASA Astrophysics Data System (ADS)

    Elias, Thierry; Ramon, Didier; Dubus, Laurent; Bourdil, Charles; Cuevas-Agulló, Emilio; Zaidouni, Taoufik; Formenti, Paola

    2016-05-01

    Aerosols attenuate the solar radiation collected by solar tower plants (STP), along two pathways: 1) the atmospheric column pathway, between the top of the atmosphere and the heliostats, resulting in Direct Normal Irradiance (DNI) changes; 2) the grazing pathway close to surface level, between the heliostats and the optical receiver. The attenuation along the surface-level grazing pathway has been less studied than the aerosol impact on changes of DNI, while it becomes significant in STP of 100 MW or more. Indeed aerosols mostly lay within the surface atmospheric layer, called the boundary layer, and the attenuation increases with the distance covered by the solar radiation in the boundary layer. In STP of 100 MW or more, the distance between the heliostats and the optical receiver becomes large enough to produce a significant attenuation by aerosols. We used measured aerosol optical thickness and computed boundary layer height to estimate the attenuation of the solar radiation at surface level at Ouarzazate (Morocco). High variabilities in aerosol amount and in vertical layering generated a significant magnitude in the annual cycle and significant inter-annual changes. Indeed the annual mean of the attenuation caused by aerosols over a 1-km heliostat-receiver distance was 3.7% in 2013, and 5.4% in 2014 because of a longest desert dust season. The monthly minimum attenuation of less than 3% was observed in winter and the maximum of more than 7% was observed in summer.

  10. An assessment of ozone levels, UV radiation and their occupational health hazard estimation during photocopying operation.

    PubMed

    Singh, Bhupendra Pratap; Kumar, Amit; Singh, Deepak; Punia, Monika; Kumar, Krishan; Jain, Vinod Kumar

    2014-06-30

    This study investigates the levels of ozone concentration along with an ultraviolet (UV) and visible spectral radiation at eight photocopy centers in an academic institute, Delhi. Sampling was done in two types of locations, i.e., basement photocopy centers (BPC) and ground floor photocopy centers (GPC) for 8h. Measurements of levels of ozone, UV and visible radiation were done by ozone analyzer, UV radiometer and Field spectra instrument, respectively. Results show that the hourly mean concentration of ozone was observed to be in the range of 1.8-10.0 ppb and 5.3-45.8 ppb for BPC and GPC, respectively. In terms UV radiations, energy lies between 5.0×10(-3) and 7.0×10(-3) mW/cm(2) for ultraviolet A (UVA), 1.0×10(-3) and 2.0×10(-3) mW/cm(2) for ultraviolet B (UVB) and 6.0×10(-3) and 8.0×10(-3) mW/cm(2) for ultraviolet C (UVC). Correlation between the UV radiations and ozone production observed was statistically insignificant. To know the health hazard occurred to the workers, the standard erythema dose (SED) value was calculated for emitting UV radiation. The SED was estimated to be in the range of 0.02-0.04 and 0.02-0.32 for direct and indirect methods which is less than the guideline prescribed by Commission Internationale del' Eclairage (CIE). In nutshell, person involved in photocopy operation for their livelihood must be trained and should have knowledge for the long term gradual build up health problems due to ozone and UV production from photocopier. The manufactures should be ultimated with the significant ozone production, so that photocopier machine can be redesigned. PMID:24857892