WorldWideScience

Sample records for background radiation

  1. Determination of background radiation

    International Nuclear Information System (INIS)

    The invention relates to a method and appartus for determining the level of background radiation in a spectral region where a Raman peak characteristic of a particular substance, in particular diamond, is expected to occur. The method includes the steps of isolating the radiation in a first spectral band, and isolating the radiation in a second spectral band which overlaps the first spectral band at least partially to form an overlapping band in the vicinity of the expected Raman Peak and a least one sideband. At least one sideband value representative of the radiation present in the one or more sidebands is then obtained, and further values, representative of the radiation isolated by any one or more of the other spectral bands, such as the first and second bands, are then used to derive a background value indicative of the level of background radiation present at the position of the expected Raman peak

  2. The natural radiation background

    International Nuclear Information System (INIS)

    The components of the natural background radiation and their variations are described. Cosmic radiation is a major contributor to the external dose to the human body whilst naturally-occurring radionuclides of primordial and cosmogenic origin contribute to both the external and internal doses, with the primordial radionuclides being the major contributor in both cases. Man has continually modified the radiation dose to which he has been subjected. The two traditional methods of measuring background radiation, ionisation chamber measurements and scintillation counting, are looked at and the prospect of using thermoluminescent dosimetry is considered

  3. Local microwave background radiation

    OpenAIRE

    Soares, Domingos

    2006-01-01

    An inquiry on a possible local origin for the Microwave Background Radiation is made. Thermal MBR photons are contained in a system called {\\it magnetic bottle} which is due to Earth magnetic field and solar wind particles, mostly electrons. Observational tests are anticipated.

  4. Cosmic Tachyon Background Radiation

    CERN Document Server

    Tomaschitz, R

    1999-01-01

    The equilibrium statistical mechanics of a background radiation of superluminal particles is investigated, based on a vectorial wave equation for tachyons of the Proca type. The partition function, the spectral energy density, and the various thermodynamic variables of an ideal Bose gas of tachyons in an open Robertson-Walker cosmology are derived. The negative mass square in the wave equation changes the frequency scaling in the Rayleigh-Jeans law, and there are also significant changes in the low temperature regime as compared to the microwave background, in particular in the caloric and thermal equations of state.

  5. The Cosmic Background Radiation

    OpenAIRE

    Smoot, George; Scott, Douglas

    1997-01-01

    We review the current status of experimental data for spectral distortions and angular anisotropies of the cosmic microwave background, as well as discussing the relevant physical processes. This is one of a number of new articles in astrophysics and cosmology which will appear in the 1996 Review of Particle Properties (Phys. Rev. D. in press). Other relevant reviews include: "Big-Bang Cosmology" by K.A. Olive; "Big-Bang Nucleosynthesis" by K.A. Olive & D.N. Schramm; "The Hubble Constant" by ...

  6. Natural background radiation in Jordan

    International Nuclear Information System (INIS)

    An Airborne Gamma Ray survey has been accomplished for Jordan since 1979. A complete report has been submitted to the Natural Resources Authority along with field and processed data ''digital and analogue''. Natural radioelements concentration is not provided with this report. From the corrected count rate data for each natural radioelement, Concentrations and exposure rates at the ground level were calculated. Contoured maps, showing the exposure rates and the dose rates were created. Both maps reflect the surface geology of Jordan, where the Phosphate areas are very well delineated by high-level contours. In southeastern Jordan the Ordovician sandstone, which contain high percentage of Th (around 2000 ppm in some places) and a moderate percentage of U (about 300 ppm), also show high gamma radiation exposures compared with the surrounding areas. Comparing the values of the exposure rates given in (μR/h) to those obtained from other countries such as United States, Canada, Germany, etc. Jordan shows higher background radiation which reach two folds and even more than those in these countries. More detailed studies should be performed in order to evaluate the radiological risk limits on people who are living in areas of high radiation such that the area of the phosphatic belt which covers a vast area of Jordan high Plateau. (author)

  7. Cosmic background radiation: a hagiography

    Energy Technology Data Exchange (ETDEWEB)

    Abramo, Luis Raul [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica

    2009-07-01

    Full text. Cosmology advanced tremendously since Gamow and his students predicted the cosmic microwave background radiation, and since Penzias and Wilson observed it for the first time. The observations of the CMBR point to a Universe which is beautiful in its simplicity: the amazing richness of structures can be explained by a minimalistic set of well-known physical laws, a reasonable amount of free parameters, and 'natural' initial conditions which realize the idea of maximum entropy. We will revise the latest observations and show how the CMBR is presently allowing the study of the 'fine structure' of cosmological phenomena. We will also discuss the possibility of a detection of rotational modes (B-modes) in the polarization of the CMBR, that may reveal which processes (inflation ?) acted in the very early universe to endow it with these beautiful and simple properties. (author)

  8. Cosmic background radiation: a hagiography

    International Nuclear Information System (INIS)

    Full text. Cosmology advanced tremendously since Gamow and his students predicted the cosmic microwave background radiation, and since Penzias and Wilson observed it for the first time. The observations of the CMBR point to a Universe which is beautiful in its simplicity: the amazing richness of structures can be explained by a minimalistic set of well-known physical laws, a reasonable amount of free parameters, and 'natural' initial conditions which realize the idea of maximum entropy. We will revise the latest observations and show how the CMBR is presently allowing the study of the 'fine structure' of cosmological phenomena. We will also discuss the possibility of a detection of rotational modes (B-modes) in the polarization of the CMBR, that may reveal which processes (inflation ?) acted in the very early universe to endow it with these beautiful and simple properties. (author)

  9. The Cosmic Background Radiation, 1997

    CERN Document Server

    Smoot, G F; Smoot, George; Scott, Douglas

    1997-01-01

    We summarise the current status of cosmic microwave background spectrum and anisotropy measurements, and their theoretical interpretation. This is the update of the mini-review for the 1997 web-version of the Review of Particle Properties.

  10. Natural background radiation in Canada

    International Nuclear Information System (INIS)

    Published airborne gamma ray survey data from 33 areas of Canada were used to compile information on the average ground level exposure from natural radiation. The exposures at ground level were calculated from the surface concentrations of potassium, uranium and thorium. The highest levels of radioactivity were found in northern Canada and were generally related to granitic rocks; the lowest levels with the Athabasca sandstone. Summer outdoor exposure rates have a population-weighted average of 3.7 +- 2.3 μR.h-1, of which 48 percent orginated from potassium, 43 percent from the thorium series and 9 percent from the uranium series. This low level of radioactivity, compared to worldwide data, has resulted from erosion of a geologically old continental crust in which radioactivity decreases with depth. When seasonal variations of soil moisture and snow cover are considered, the annual population-weighted average outdoor exposure rate decreases to 2.8 +- 1.7 μR.h-1 corresponding to an annual outdoor dose-equivalent of 150 +- 90 μSV. Factors increasing the annual outdoor dose-equivalent are cosmic radiation (320 +- 30 μSV) and the internal radioactivity of the body (190 μSV). Using the ratio between indoor and outdoor values for worldwide published data, the average annual Canadian whole-body dose-equivalent from all sources of natural radiation is estimated to be 690 +-130 μSV

  11. The Cosmic Background Radiation, 1995

    CERN Document Server

    Smoot, G F

    1995-01-01

    Observations of the Cosmic Microwave background have provided many of the most powerful constraints we have on cosmology and events in the early universe. The spectrum and isotropy of CBR have long been a pillar of Big Bang models. The discovery of low levels on anisotropy has provided new information and tools for our understanding of the early universe. Further observations promise to enhance greatly our knowledge of processes in the early universe and cosmological parameters. We can anticipate rapid advance in this field up to and through the year 2000 which will dramatically focus our efforts in cosmology during the next millenium. This paper outlines the primary science likely to be discovered and defined by a vigorous airborne and ground-based program which should be strongly supported. If successfully excuted, we an anticipate a measurement of the CBR anisotropy spectrum to within a factor of two of the confidence level unavoidably set by cosmic variance. Even so, observations of the CBR are the best a...

  12. Radiation background of Black Sea coastal environment

    International Nuclear Information System (INIS)

    The main objective of the project is to establish the level of radiation background and its sources in the Black Sea coastal environment. Marine samples will be collected in the Black Sea Coast area. The content of different radionuclides will be analyzed and the results will be used in a GIS application. The gamma emitting radionuclides will be measured in ultralow radiation background in the Romanian underground laboratory in salt mine in Slanic-Prahova. The main expected results is an up to date quantification of the radiation sources of the background of the Black Sea coastal environment. (authors)

  13. Background radiation levels and standards for protection from ionizing radiations

    International Nuclear Information System (INIS)

    Apart from the amount of radiation which a worker may receive while he performs his work, he is also exposed to radiation because of the nature of his environment. In other words, all individuals are subject to some irradiation even though they may not work with radioactive substances. This source of radiation exposure is often referred to as background radiation. In most environments, it is low-level and can be grouped into two natural and man-made. Background radiation provides the basis on which allowable exposure limits for workers are drawn

  14. Natural background radiation and oncologic disease incidence

    International Nuclear Information System (INIS)

    Cause and effect relationships between oncologic disease incidence in human population and environmental factors are examined using investigation materials of Soviet and foreign authors. The data concerning US white population are adduced. The role and contribution of natural background radiation oncologic disease prevalence have been determined with the help of system information analysis. The probable damage of oncologic disease is shown to decrease as the background radiation level diminishes. The linear nature of dose-response relationspip has been established. The necessity to include the life history of the studied population along with environmental factors in epidemiological study under conditions of multiplicity of cancerogenesis causes is emphasized

  15. Ponderable soliton stars and cosmic background radiation

    Science.gov (United States)

    Chiu, Hong-Yee

    1990-01-01

    A theory is developed to describe the possible perturbations of the cosmic background radiation (CBR) by radiation from ponderable soliton stars in the early universe. Since the temperature of such stars is in the range of 10 to the 6th K, thermalization of their emitted radiation is possible. Two models are considered: one in which thermalization is ignored and one in which decoupling from thermalization is considered as a sudden process. The expected perturbation of the CBR is probably less than 1 percent and is largely around the short-wavelength end, in the form of point radio sources. This result is consistent with the most recent COBE measurements.

  16. Epidemiological studies in high background radiation areas

    International Nuclear Information System (INIS)

    Below the doses of 100-200 mSv of radiation exposure, no acute health effect is observed, and the late health effects such as cancer are yet unclear. The problems making the risk evaluation of low dose radiation exposure difficult are the fact that the magnitude of expected health effects are small even if the risk is assumed to increase in proportion to radiation doses. As a result, studies need to be large particular when dealing with rare disease such as cancer. In addition, the expected health effects are so small that they can easily be masked by lifestyles and environmental factors including smoking. This paper will discuss cancer risk possibly associated with low-dose and low-dose rate radiation exposure, describing epidemiological studies on the residents in the high-background radiation areas. (author)

  17. Exposure to background radiation in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, S.B. [Australian Radiation Lab., Melbourne, VIC (Australia)

    1997-12-31

    The average effective dose received by the Australian population is estimated to be {approx}1.8 mSv / year. One half of this exposure arises from exposure from terrestrial radiation and cosmic rays, the remainder from radionuclides within the body and from inhalation of radon progeny. This paper reviews a number of research programmes carried out by the Australian Radiation Laboratory to study radiation exposure from natural background, particularly in the workplace and illustrate approaches to the quantification and management of exposure to natural radiation. The average radiation doses to the Australian population are relatively low; the average annual radon concentration ranged from 6 Bq m{sup -3} in Queensland to 16 Bq m{sup -3} in the Australian Capital Territory (ACT). Of more importance is the emerging issue of exposure to elevated background radiation in the workplace. Two situation are presented; the radiation exposure to air crues and show cave tour guides. Annual doses up to 3.8 mSv were estimated for international crew members while the highest estimate for show cave tour guides was 9 mSv per year. 9 refs., 2 tabs., 4 figs.

  18. Exposure to background radiation in Australia

    International Nuclear Information System (INIS)

    The average effective dose received by the Australian population is estimated to be ∼1.8 mSv / year. One half of this exposure arises from exposure from terrestrial radiation and cosmic rays, the remainder from radionuclides within the body and from inhalation of radon progeny. This paper reviews a number of research programmes carried out by the Australian Radiation Laboratory to study radiation exposure from natural background, particularly in the workplace and illustrate approaches to the quantification and management of exposure to natural radiation. The average radiation doses to the Australian population are relatively low; the average annual radon concentration ranged from 6 Bq m-3 in Queensland to 16 Bq m-3 in the Australian Capital Territory (ACT). Of more importance is the emerging issue of exposure to elevated background radiation in the workplace. Two situation are presented; the radiation exposure to air crues and show cave tour guides. Annual doses up to 3.8 mSv were estimated for international crew members while the highest estimate for show cave tour guides was 9 mSv per year

  19. Controllable forms of natural background radiation

    International Nuclear Information System (INIS)

    RENA is a research programm into the controllable forms of natural background radiation, which cover the activities originating from the naturally occurring radionuclides enhanced by human intervention. In the RENA-program emphasis lays upon the policy aspects of environmental-hygienic, economical and governmental character. (H.W.). 15 refs.; 2 tabs

  20. Ultraviolet Background Radiation from Cosmic Structure Formation

    OpenAIRE

    Miniati, Francesco; Ferrara, Andrea; White, Simon D. M.; Bianchi, Simone

    2003-01-01

    We calculate the contribution to the ultraviolet background (UVB) from thermal emission from gas shock heated by cosmic structure formation. Our main calculation is based on an updated version of Press-Schechter theory. It is consistent with a more empirical estimate based on the observed properties of galaxies and the observed cosmic star formation history. Thermal UVB emission is characterized by a hard spectrum extending well beyond 4 Ry. The bulk of the radiation is produced by objects in...

  1. Remote Background Radiation Monitoring Using Zigbee Technology

    Directory of Open Access Journals (Sweden)

    Hamisu A. Adamu

    2014-03-01

    Full Text Available In this paper, a solution of remote background radiation monitoring, based on the concept of Wireless Sensor Network (WSN, is presented. Radiation dose rate measured by the sensor node is sent to the monitoring station through ZigBee wireless network operated on 2.4 GHz unlicensed Industrial Scientific Medical (ISM band. The system is calibrated for use for ionizing radiation dose rate range of between naturally occurring background radiation and 1.02 mSv/h. Power consumption of the sensor node is kept low by operating the node ZigBee radio with low duty cycle: i.e by keeping the radio awake only during data transmission/reception. Two ATmega8 microcontrollers, one each for sensor node and the monitoring station, are programmed to perform interfacing, data processing, and control functions. The system range of coverage is 124m for outdoor (line of site deployment and 56.8m for indoor application where 5 brick walls separated the sensor node and the monitoring station. Range of coverage of the system is extendable via the use of ZigBee router(s.

  2. Natural background approach to setting radiation standards

    International Nuclear Information System (INIS)

    The suggestion has often been made that an additional radiation exposure imposed on humanity as a result of some important activity such as electricity generation would be acceptable if the exposure was small compared to the natural background. In order to make this concept quantitative and objective, we propose that small compared with the natural background be interpreted as the standard deviation (weighted with the exposed population) of the natural background. This use of the variation in natural background radiation is less arbitrary and requires fewer unfounded assumptions than some current approaches to standard-setting. The standard deviation is an easily calculated statistic that is small compared with the mean value for natural exposures of populations. It is an objectively determined quantity and its significance is generally understood. Its determination does not omit any of the pertinent data. When this method is applied to the population of the United States, it suggests that a dose of 20 mrem/year would be an acceptable standard. This is comparable to the 25 mrem/year suggested as the maximum allowable exposure to an individual from the complete uranium fuel cycle

  3. Polarization of the cosmic background radiation

    International Nuclear Information System (INIS)

    The results and technique of a measurement of the linear polarization of the Cosmic Background Radiation are discussed. The ground-based experiment utilizes a single horn (70 beam width) Dicke-type microwave polarimeter operating at 33 GHz (9.1 mm). Data taken between May 1978 and February 1980 from both the northern hemisphere (Berkeley Lat. = 380N) and the southern hemisphere (Lima Lat. = 120S) show the radiation to be essentially unpolarized over all areas surveyed. For the 380 declination data the 95% confidence level limit on a linearly polarized component is 0.3 mK for the average and 12 and 24 hour periods. Fitting all data gives the 95% confidence level limit on a linearly polarized component of 0.3 mK for spherical harmonics through third order. Constraints on various cosmological models are discussed in light of these limits

  4. Ultraviolet Background Radiation from Cosmic Structure Formation

    CERN Document Server

    Miniati, F; White, S D M; Bianchi, S; Miniati, Francesco; Ferrara, Andrea; White, Simon D. M.; Bianchi, Simone

    2004-01-01

    We calculate the contribution to the ultraviolet background (UVB) from thermal emission from gas shock heated by cosmic structure formation. Our main calculation is based on an updated version of Press-Schechter theory. It is consistent with a more empirical estimate based on the observed properties of galaxies and the observed cosmic star formation history. Thermal UVB emission is characterized by a hard spectrum extending well beyond 4 Ry. The bulk of the radiation is produced by objects in the mass range 10^11-13 M_solar, i.e. large galaxies and small groups. We compute a composite UVB spectrum due to QSO, stellar and thermal components. The ratio of the UVB intensities at the H and He Lyman limits increases from 60 at z=2 to more than 300 at z=6. A comparison of the resulting photoionization rates to the observed Gunn-Peterson effect at high redshifts constrains the escape fraction of ionizing photons from galaxies to be less than a few percent. Near 1 Ry, thermal and stellar emission are comparable amoun...

  5. Thermal radiation of various gravitational backgrounds

    OpenAIRE

    Akhmedov, Emil T.; Akhmedova, Valeria; Pilling, Terry; Singleton, Douglas

    2006-01-01

    We present a simple and general procedure for calculating the thermal radiation coming from any stationary metric. The physical picture is that the radiation arises as the quasi--classical tunneling of particles through a gravitational barrier. We show that our procedure can reproduce the results of Hawking and Unruh radiation. We also show that under certain kinds of coordinate transformations the temperature of the thermal radiation will change in the case of the Schwarzschild black holes. ...

  6. Ultraviolet background radiation from cosmic structure formation

    Science.gov (United States)

    Miniati, Francesco; Ferrara, Andrea; White, Simon D. M.; Bianchi, Simone

    2004-03-01

    We calculate the contribution to the ultraviolet background (UVB) from thermal emission from gas shock heated during cosmic structure formation. Our main calculation is based on an updated version of Press-Schechter theory. It is consistent with a more empirical estimate based on the observed properties of galaxies and the observed cosmic star formation history. Thermal UVB emission is characterized by a hard spectrum extending well beyond 4 Ryd. The bulk of the radiation is produced by objects in the mass range 1011-1013 Msolar, i.e. large galaxies and small groups. We compute a composite UVB spectrum due to quasi-stellar object (QSO), stellar and thermal components. The ratio of the UVB intensities at the H and He Lyman limits increases from 60 at z= 2 to more than 300 at z= 6. A comparison of the resulting photoionization rates to the observed Gunn-Peterson effect at high redshifts constrains the escape fraction of ionizing photons from galaxies to be less than a few per cent. Near 1 Ryd, thermal and stellar emission are comparable, amounting to about 10, 20 and 35 per cent of the total flux at redshifts of 3, 4.5 and higher, respectively. However, near the ionization threshold for He II, the thermal contribution is much stronger. It is comparable to the QSO intensity already at redshift ~3 and dominates at redshifts above 4. Thermal photons alone are enough to produce and sustain He II reionization already at z~ 6. We discuss the possible implications of our results for the thermal history of the intergalactic medium, in particular for He II reionization.

  7. Structures in the microwave background radiation

    CERN Document Server

    Meissner, K A; Ruszczycki, B

    2012-01-01

    We compare the actual WMAP maps with artificial, purely statistical maps of the same harmonic content to argue that there are, with confidence level 99.7 %, ring-type structures in the observed cosmic microwave background.

  8. Spectral Analysis in High Radiation Space Backgrounds with Robust Fitting

    Science.gov (United States)

    Lasche, G. P.; Coldwell, R. L.; Nobel, L. A.; Rester, A. C.; Trombka, J. I.

    1997-01-01

    Spectral analysis software is tested for its ability to fit spectra from space. The approach, which emphasizes the background shape function, is uniquely suited to the identification of weak-strength nuclides in high-radiation background environments.

  9. The Cosmic Background Radiation, Snowmass Workshop

    OpenAIRE

    Smoot, George F.

    1995-01-01

    Observations of the Cosmic Microwave background have provided many of the most powerful constraints we have on cosmology and events in the early universe. The spectrum and isotropy of CBR have long been a pillar of Big Bang models. The discovery of low levels on anisotropy has provided new information and tools for our understanding of the early universe. Further observations promise to enhance greatly our knowledge of processes in the early universe and cosmological parameters. We can antici...

  10. Cosmic far-ultraviolet background radiation

    International Nuclear Information System (INIS)

    It is demonstrated that interstellar dust grains forward-scatter far-ultraviolet radiation extremely strongly: the value of the Henyey-Greenstein scattering parameter g at 1425 A is shown to be at least 0.75; the actual value is very likely greater than 0.9. Also, observations of the Virgo cluster of galaxies sets a limit tau > 2 x 1025 sec on the life-time of 17-20 eV/c2 heavy neutrinos, if such neutrinos are responsible for the gravitational binding of the cluster. (Auth.)

  11. Formation of Primordial Galaxies under UV background Radiation

    CERN Document Server

    Susa, H; Susa, Hajime; Umemura, Masayuki

    2000-01-01

    The pancake collapse of pregalactic clouds under UV background radiation is explored with a one-dimensional sheet model. Here, attention is concentrated on elucidating the basic physics on the thermal evolution of pregalactic clouds exposed to diffuse UV radiation. So, we treat accurately the radiation transfer for the ionizing photons, with solving chemical reactions regarding hydrogen molecules as well as atoms. The self-shielding against UV radiation by H$_2$ Lyman-Werner bands, which regulates the photo-dissociation of hydrogen molecules, is also taken into account. As a result, it is found that when the UV background radiation is at a level of $10^{-22} (\

  12. Radiation background with the CMS RPCs at the LHC

    International Nuclear Information System (INIS)

    The Resistive Plate Chambers (RPCs) are employed in the CMS Experiment at the LHC as dedicated trigger system both in the barrel and in the endcap. This article presents results of the radiation background measurements performed with the 2011 and 2012 proton-proton collision data collected by CMS. Emphasis is given to the measurements of the background distribution inside the RPCs. The expected background rates during the future running of the LHC are estimated both from extrapolated measurements and from simulation

  13. Natural background as an indicator of radiation-induced cancer

    International Nuclear Information System (INIS)

    A review of the estimates for radiation-induced cancer rates is presented including the recent high estimates of 8 x 10-3 cancers/man rem. Also reviewed are the external background radiation and cancer incidence for the USA by state. A regression analysis of these data reveals a negative correlation between radiation dose and cancer rate, but only with a correlation coefficient of 0.39. However, the cancer induction rate of 8 x 10-3/man rem is shown to describe the observed data with a probability of 1 in 14,000. Thus such high estimates of radiation-induced cancer rate are highly improbable. (UK)

  14. Natural background radiation and population dose in China

    Energy Technology Data Exchange (ETDEWEB)

    Guangzhi, C. (Ministry of Public Health, Beijing, BJ (China)); Ziqiang, P.; Zhenyum, H.; Yin, Y.; Mingqiang, G.

    On the basis of analyzing the data for the natural background radiation level in China, the typical values for indoor and outdoor terrestrial gamma radiation and effective dose equivalents from radon and thoron daughters are recommended. The annual effective dose equivalent from natural radiation to the inhabitant is estimated to be 2.3 mSv, in which 0.54 mSv is from terrestrial gamma radiation and about 0,8 mSv is from radon and its short-lived daughters. 55 Refs.

  15. Estimates of dose equivalent rates from natural background radiation

    International Nuclear Information System (INIS)

    Environmental monitoring in Khartoum is being conducted using thermoluminescent dosimetry.The purpose of the study is to estimate dose-equivalent rates from natural background radiation.TL phosphorus LiF.Mg, Cu, P and CaSO4:Mn were used to measure the exposure over land for natural background radiation of terrestrial origin plus cosmic radiation and at position over the Blue Nile to account for natural background radiation of extraterrestrial origin (cosmic rays).The associated dose-equivalent rates have been determined.It was found that the dose-equivalent rates from cosmic radiation obtained through this work using the two types of the TLD phosphorus GR-200 A and CaSO4 are 0.295 mSv per year and 0.265 mSv per year, respectively.While the dose-equivalent rates from total natural background radiation obtained through this work are 0.395 mSv per year using GR-200 A and CaSO4 phosphorus, respectively. (Author)

  16. Spectrum and isotropy of the submillimeter background radiation

    International Nuclear Information System (INIS)

    Two great astronomical discoveries have most shaped our present concept of the Big Bang universe. Like the Hubble recession of the galaxies, the discovery of the 30K background radiation by Penzias and Wilson in 1965 has given rise to a line of research which is still very active today. Penzias and Wilson's universal microwave background at 7 cm was immediately interpreted by R.H. Dicke's group at Princeton as coming from the primordial fireball of incandescent plasma which filled the universe for the million years or so after its explosive birth. This interpretation gives rise to two crucial predictions as to the nature of the background radiation. Its spectrum should be thermal even after having been red shifted by a factor of approximately 1000 by the expansion of the universe, and the radiation should be isotropic - assuming that the universe itself is isotropic. If the background radiation is indeed from the primordial fireball it affords us the only direct view at the very young universe. This paper deals with the spectrum and then the isotropy of the background radiation, with emphasis on high frequency or submillimeter measurements. Prospects for the future are discussed briefly. (Auth.)

  17. EPR dosimetry of radiation background in the Urals region

    Energy Technology Data Exchange (ETDEWEB)

    Shishkina, E.A.; Degteva, M.O.; Shved, V.A. [Urals Research Center for Radiation Medicine, 48-A Vorovsky, Chelyabinsk 454076 (Russian Federation); Fattibene, P.; Onori, S. [Istituto Superiore di Sanita and Istituto Nazionale di Fisica Nucleare (Italy); Wieser, A. [GSF, Forschungszentrum fuer Umwelt und Gesundheit, Ingolstaedter Landstr (Germany); Ivanov, D.V.; Bayankin, S.N. [Institute of Metal Physics, Russian Academy of Sciences (Russian Federation); Knyazev, V.A.; Vasilenko, E.I.; Gorelov, M. [ZAO, Closed Corporation ' Company GEOSPETSECOLOGIA' (Russian Federation)

    2006-07-01

    Method of Electron Paramagnetic Resonance is extensively applied to individual retrospective dosimetry. The background dose is unavoidable component of cumulative absorbed dose in the tooth enamel accumulated during the lifetime of donor. Estimation of incidental radiation dose using tooth enamel needs in extraction of background dose. Moreover, the variation of background doses in the population is a limited factor for reliable detection of additional irradiation especially for low dose level. Therefore the accurate knowledge of the natural background radiation dose is a critical element of EPR studies of exposed populations. In the Urals region the method applies for such two large cohorts as the workers of Mayak (Ozersk citizens) and Techa River riverside inhabitants (rural population). Current study aimed to investigate the Urals radiation background detected by EPR spectrometry. For this aim two group of unexposed Urals residents were separated, viz: citizens of Ozersk and rural inhabitants of Chelyabinsk region. Comparison of two investigated territories has demonstrated that from the point of view of radiation background it is impossible to assume the Urals population as uniform. The reliable difference between the urban and rural residents has been found. The average background doses of Ozersk donors is in average 50 mGy higher than those detected for rural residents. The individual variability of background doses for Osersk has been higher than in the rural results. The difference in background dose levels between two population results in different limits of accidental dose detection and individualization. The doses for 'Mayak' workers (Ozyorsk citizens) can be classed as anthropogenic if the EPR measurements exceed 120 mGy for teeth younger than 40 years, and 240 mGy for teeth older than 70 years. The anthropogenic doses for Techa River residents (rural population) would be higher than 95 mGy for teeth younger than 50 years and 270 mGy for

  18. EPR dosimetry of radiation background in the Urals region

    International Nuclear Information System (INIS)

    Method of Electron Paramagnetic Resonance is extensively applied to individual retrospective dosimetry. The background dose is unavoidable component of cumulative absorbed dose in the tooth enamel accumulated during the lifetime of donor. Estimation of incidental radiation dose using tooth enamel needs in extraction of background dose. Moreover, the variation of background doses in the population is a limited factor for reliable detection of additional irradiation especially for low dose level. Therefore the accurate knowledge of the natural background radiation dose is a critical element of EPR studies of exposed populations. In the Urals region the method applies for such two large cohorts as the workers of Mayak (Ozersk citizens) and Techa River riverside inhabitants (rural population). Current study aimed to investigate the Urals radiation background detected by EPR spectrometry. For this aim two group of unexposed Urals residents were separated, viz: citizens of Ozersk and rural inhabitants of Chelyabinsk region. Comparison of two investigated territories has demonstrated that from the point of view of radiation background it is impossible to assume the Urals population as uniform. The reliable difference between the urban and rural residents has been found. The average background doses of Ozersk donors is in average 50 mGy higher than those detected for rural residents. The individual variability of background doses for Osersk has been higher than in the rural results. The difference in background dose levels between two population results in different limits of accidental dose detection and individualization. The doses for 'Mayak' workers (Ozyorsk citizens) can be classed as anthropogenic if the EPR measurements exceed 120 mGy for teeth younger than 40 years, and 240 mGy for teeth older than 70 years. The anthropogenic doses for Techa River residents (rural population) would be higher than 95 mGy for teeth younger than 50 years and 270 mGy for teeth older

  19. Natural background radiation and population dose distribution in India

    International Nuclear Information System (INIS)

    A country-wide survey of the outdoor natural background gamma radiation levels has been made using mailed thermoluminescent dosimeters (TLDs). The salient features of the results are: (1) The air-kerma levels and the population doses in various states follow log-normal and normal distributions respectively. (2) The national average value for the air dose (air-kerma) is 775 ± 370 (1σ)μGy/y. (3) The lowest air-kerma recorded is 0.23 mGy/y at Minicoy (Laccadive Islands) and the highest is 26.73 mGy/y at Chavra (monazite areas, Kerala). (4) There are significant temporal variation s (even as high as ± 40 per cent) of the background radiation level at many locations and at least in 10 locations where radon/thoron measurements are available, these could be associated with the seasonal variations in radon/thoron levels. (5) The mail control TLDs indicate a country-wide average value of 785 ± 225 μGy/y for the air-kerma which can be considered to provide a truly national average value for the natural background radiation level in India. (6) The mean natural radiation per caput for the country works out to be 690 ± 200 (1σ) Sv/y. (7) The natural radiation per caput seems to be maximum for Andhra Pradesh (1065 ± 325 μSv/y) and minimum for Maharashtra (370 ± 80 μSv/y). (8) The population dose from the external natural background radiation is estimated to be half a million person-Sievert. (9) Assuming 1 CRP risk factor, it can be estimated that just one out of the 43 cancer deaths occurring on an average per 100,000 population in India, can be attributed to the external natural background radiation. (author). 18 refs., 13 tabs., 9 figs

  20. An intercomparison of detectors for measurement of background radiation

    International Nuclear Information System (INIS)

    Measurements of the background radiation were made in 1978 at 14 locations with a high-pressure ionization chamber, thermoluminiscence dosimeters (TLD's), two NaI(Tl) detectors, and a Ge(Li) spectrometer system. Simultaneous measurements with the ionization chamber and the spectrometer system provide reliable estimates of the total background exposure rate, of the individual contributors to the terrestrial exposure rate, and of the exposure rate from the secondary cosmic radiation. The TLD results agree with those of the ionization chamber. The NaI(Tl) detector results show that accurate estimates of the terrestrial exposure rate can be obtained if empirical corrections are applied. (author)

  1. Search for radiative decays of cosmic background neutrino using cosmic infrared background energy spectrum

    International Nuclear Information System (INIS)

    We propose to search for the neutrino radiative decay by fitting a photon energy spectrum of the cosmic infrared background to a sum of the photon energy spectrum from the neutrino radiative decay and a continuum. By comparing the present cosmic infrared background energy spectrum observed by AKARI and Spitzer to the photon energy spectrum expected from neutrino radiative decay with a maximum likelihood method, we obtained a lifetime lower limit of 3.1x1012 to 3.8x1012 years at 95% confidence level for the third generation neutrino v3 in the v3 mass range between 50 and 150 meV/c2 under the present constraints by the neutrino oscillation measurements. In the left-right symmetric model, the minimum lifetime of v3 is predicted to be 1.5x1017 years for m3 of 50 meV/c2. We studied the feasibility of the observation of the neutrino radiative decay with a lifetime of 1.5x1017 years, by measuring a continuous energy spectrum of the cosmic infrared background. (author)

  2. The Effects of the Ionizing Radiation Background on Galaxy Evolution

    CERN Document Server

    Hambrick, D Clay; Naab, Thorsten; Johansson, Peter H

    2009-01-01

    We find that the amount and nature of the assumed ionizing background can strongly affect galaxy formation and evolution. Galaxy evolution simulations typically incorporate an ultraviolet background which falls off rapidly above z=3; e.g., that of Haardt & Madau (1996). However, this decline may be too steep to fit the WMAP constraints on electron scattering optical depth or observations of intermediate redshift (z ~ 2-4) Ly-alpha forest transmission. As an alternative, we present simulations of the cosmological formation of individual galaxies with UV backgrounds that decline more slowly at high redshift: both a simple intensity rescaling and the background recently derived by Faucher-Giguere (2009), which softens the spectrum at higher redshifts. We also test an approximation of the X-ray background with a similar z-dependence. We find for the test galaxies that an increase in either the intensity or hardness of ionizing radiation generically pushes star formation towards lower redshifts: although overa...

  3. Background Radiation Measurements at High Power Research Reactors

    CERN Document Server

    Ashenfelter, J; Baldenegro, C X; Band, H R; Barclay, G; Bass, C D; Berish, D; Bowden, N S; Bryan, C D; Cherwinka, J J; Chu, R; Classen, T; Davee, D; Dean, D; Deichert, G; Dolinski, M J; Dolph, J; Dwyer, D A; Fan, S; Gaison, J K; Galindo-Uribarri, A; Gilje, K; Glenn, A; Green, M; Han, K; Hans, S; Heeger, K M; Heffron, B; Jaffe, D E; Kettell, S; Langford, T J; Littlejohn, B R; Martinez, D; McKeown, R D; Morrell, S; Mueller, P E; Mumm, H P; Napolitano, J; Norcini, D; Pushin, D; Romero, E; Rosero, R; Saldana, L; Seilhan, B S; Sharma, R; Stemen, N T; Surukuchi, P T; Thompson, S J; Varner, R L; Wang, W; Watson, S M; White, B; White, C; Wilhelmi, J; Williams, C; Wise, T; Yao, H; Yeh, M; Yen, Y -R; Zhang, C; Zhang, X

    2016-01-01

    Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including $\\gamma$-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. The general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.

  4. Background radiation measurements at high power research reactors

    Science.gov (United States)

    Ashenfelter, J.; Balantekin, B.; Baldenegro, C. X.; Band, H. R.; Barclay, G.; Bass, C. D.; Berish, D.; Bowden, N. S.; Bryan, C. D.; Cherwinka, J. J.; Chu, R.; Classen, T.; Davee, D.; Dean, D.; Deichert, G.; Dolinski, M. J.; Dolph, J.; Dwyer, D. A.; Fan, S.; Gaison, J. K.; Galindo-Uribarri, A.; Gilje, K.; Glenn, A.; Green, M.; Han, K.; Hans, S.; Heeger, K. M.; Heffron, B.; Jaffe, D. E.; Kettell, S.; Langford, T. J.; Littlejohn, B. R.; Martinez, D.; McKeown, R. D.; Morrell, S.; Mueller, P. E.; Mumm, H. P.; Napolitano, J.; Norcini, D.; Pushin, D.; Romero, E.; Rosero, R.; Saldana, L.; Seilhan, B. S.; Sharma, R.; Stemen, N. T.; Surukuchi, P. T.; Thompson, S. J.; Varner, R. L.; Wang, W.; Watson, S. M.; White, B.; White, C.; Wilhelmi, J.; Williams, C.; Wise, T.; Yao, H.; Yeh, M.; Yen, Y.-R.; Zhang, C.; Zhang, X.

    2016-01-01

    Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. The general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.

  5. Position sensitive detection of neutrons in high radiation background field

    International Nuclear Information System (INIS)

    We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e− radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm2) spectroscopic Timepix detector adapted for neutron detection utilizing very thin 10B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10−4

  6. Suppressing Background Radiation Using Poisson Principal Component Analysis

    CERN Document Server

    Tandon, P; Dubrawski, A; Labov, S; Nelson, K

    2016-01-01

    Performance of nuclear threat detection systems based on gamma-ray spectrometry often strongly depends on the ability to identify the part of measured signal that can be attributed to background radiation. We have successfully applied a method based on Principal Component Analysis (PCA) to obtain a compact null-space model of background spectra using PCA projection residuals to derive a source detection score. We have shown the method's utility in a threat detection system using mobile spectrometers in urban scenes (Tandon et al 2012). While it is commonly assumed that measured photon counts follow a Poisson process, standard PCA makes a Gaussian assumption about the data distribution, which may be a poor approximation when photon counts are low. This paper studies whether and in what conditions PCA with a Poisson-based loss function (Poisson PCA) can outperform standard Gaussian PCA in modeling background radiation to enable more sensitive and specific nuclear threat detection.

  7. The Cosmic Microwave Background Radiation and its Polarization

    Science.gov (United States)

    Wollack, Edward

    2016-03-01

    The cosmic microwave background (CMB) radiation and its faint polarization have provided a unique means to constrain the physical state of the early Universe. Continued advances in instrumentation, observation, and analysis have revealed polarized radiation signatures associated with gravitational lensing and have heightened the prospects for using precision polarimetry to experimentally confront the inflationary paradigm. Characterization of this relic radiation field has the power to constrain or reveal the detailed properties of astroparticle species and long wave gravitational radiation. On going and planned CMB polarization efforts from the ground, balloon, and space borne platforms will be briefly surveyed. Recent community activities by the Inflation Probe Science Interest Group (IPSIG) will also be summarized. NASA PCOS mini-symposium (invited IPSIG talk).

  8. Alternative application for the radiation background in the development of the atlas database of atmospheric radiation

    CERN Document Server

    De la Hoz, Ivan Arturo Morales

    2014-01-01

    Nowadays radiation is one of the variables to be considered in the environmental forecasting and it is meaningful in the increase of global warming, together greenhouse effect. The radiation considered by the meteorological organizations depends on the World Radiometric Reference (WRR), the World Standard Group (WSG), addressed by the World Meteorological Organization (WMO). This work is based on the cosmic microwave background, as a variable to be estimated in order to get information about the incident radiation in the Earth's atmosphere, as a valuable and meaningful contribution in the building of the radiation atlas by the (UPME) and (IDEAM). Due to the fact that the variables considered are ultraviolet and infrared radiation, ozone column, direct radiation and diffuse radiation, the last two get the global radiation, and are the only ones to be evaluated by the national meteorological organizations in the country. The study of the cosmic background radiation as a research project will provide data which ...

  9. Cosmic microwave background radiation anisotropies in brane worlds.

    Science.gov (United States)

    Koyama, Kazuya

    2003-11-28

    We propose a new formulation to calculate the cosmic microwave background (CMB) spectrum in the Randall-Sundrum two-brane model based on recent progress in solving the bulk geometry using a low energy approximation. The evolution of the anisotropic stress imprinted on the brane by the 5D Weyl tensor is calculated. An impact of the dark radiation perturbation on the CMB spectrum is investigated in a simple model assuming an initially scale-invariant adiabatic perturbation. The dark radiation perturbation induces isocurvature perturbations, but the resultant spectrum can be quite different from the prediction of simple mixtures of adiabatic and isocurvature perturbations due to Weyl anisotropic stress. PMID:14683226

  10. Nature of the Background Ultraviolet Radiation Field at High Redshifts

    Indian Academy of Sciences (India)

    Archana Samantaray; Pushpa Khare

    2000-06-01

    We have tried to determine the flux of the ultraviolet background radiation field from the column density ratios of various ions in several absorption systems observed in the spectra of QSOs. We find that in most cases the flux is considerably higher than what has been estimated to be contributed by the AGNs. The excess flux could originate locally in hot stars. In a few cases we have been able to show that such galactic flux can only contribute a part of the total required flux. The results suggest that the background gets a significant contribution from an unseen QSO population.

  11. Wormhole solution of BD theory in an anisotropic radiation background

    Directory of Open Access Journals (Sweden)

    B. Nasre Esfahani

    2001-06-01

    Full Text Available   Time-dependent wormhole solution of the BD theory in an anisotropic radiation background is presented. It is also found that the BD scalar field depends only on time. This time dependency is in power-law form. It is shown that the wormhole geometry is valid for ω ≥ -3/2, and for any arbitrary positive values of . The GR limit of our solution is obtained for ω=0 , not for ω→∞ . Though the BD field can be non-exotic, the background material is entirely exotic.

  12. Predictions of radiation backgrounds for GRO/OSSE

    International Nuclear Information System (INIS)

    In view of the important influence of background radiation induced by the charged particle environment on the sensitivity of space-borne gamma-ray instrumentation, an extensive series of simulations has been performed on representations of the Oriented Scintillation Spectrometer Experiment and Gamma Ray Observatory Spacecraft. Previously reported results on shielding are summarised and new results are presented on the influence of detector and spacecraft orientation within anisotropic trapped proton distributions. For the cosmic ray calculation, confidence is obtained by comparison with background observations obtained during a balloon flight of a single detector unit over Alice Springs. (author)

  13. Backgrounds of computer-assisted treatment planning in radiation therapy

    International Nuclear Information System (INIS)

    Interaction of ionising radiation and living materials causes biological damage of tempory or permanent nature. In radiation therapy this phenomenon is used in a controlled fashion in order to stop the proliferation of malignant cells, while at the same time limiting the permanent damage to healthy tissues and organs to at least tolerable levels. Because of the often relatively small differences in response of malignant growths and normal tissues, the margins between tolerable and intolerable are so small that the greatest precision in treatment planning and execution is required. The nature of this treatment agent implies that the radiation therapist has to rely very much on instrumentally obtained and processed information, in all phases of this medical activities around the patient. In this paper a description is given of the backgrounds of computer-assisted methods which have enabled modern individualised and optimised planning for therapy with high energy X- and gamma beams. (orig.)

  14. CERN-derived analysis of lunar radiation backgrounds

    Science.gov (United States)

    Wilson, Thomas L.; Svoboda, Robert

    1993-01-01

    The Moon produces radiation which background-limits scientific experiments there. Early analyses of these backgrounds have either failed to take into consideration the effect of charm in particle physics (because they pre-dated its discovery), or have used branching ratios which are no longer strictly valid (due to new accelerator data). We are presently investigating an analytical program for deriving muon and neutrino spectra generated by the Moon, converting an existing CERN computer program known as GEANT which does the same for the Earth. In so doing, this will (1) determine an accurate prompt neutrino spectrum produced by the lunar surface; (2) determine the lunar subsurface particle flux; (3) determine the consequence of charm production physics upon the lunar background radiation environment; and (4) provide an analytical tool for the NASA astrophysics community with which to begin an assessment of the Moon as a scientific laboratory versus its particle radiation environment. This will be done on a recurring basis with the latest experimental results of the particle data groups at Earth-based high-energy accelerators, in particular with the latest branching ratios for charmed meson decay. This will be accomplished for the first time as a full 3-dimensional simulation.

  15. Down syndrome and the high background radiation areas of Kerala

    International Nuclear Information System (INIS)

    Down syndrome (DS) or trisomy-21 is a complex human clinical entity compromising several functional, structural and developmental features with wide variation in expression levels. The diagnosis is confirmed in majority of the cases by an extra dose of chromosome 21 by cytogenetics and occasionally it may be due to either chromosomal translocation or mosaicism (different cell lines in the same individual). The extra chromosome 21 is usually formed by non-disjunction during meiosis and is the most common numerical chromosomal anomaly compatible with life, as chromosome 21 is one of the smallest with relatively fewer genes most of which are reckoned to be non lethal. Though exact causative factors and pathogenesis is not fully understood, a rise in maternal age at conception coupled with deleterious environmental influence on an ageing ovum is a recognized risk factor. The de novo nature of trisomy-21 and its relatively higher frequency makes it a reliable indicator to assess the role of chronic high background radiation in inducing germ line mutation and congenital malformation. Many other relatively common congenital malformations with multifactorial origin may not have this de novo property and associating its incidence with the prevailing natural background radiation become more complex. In vitro studies have shown association between high intensity radiation and genetics effects but such a relationship so far was not established between DS and radiation

  16. Assessment of Radiation Background Variation for Moving Detection Systems

    Energy Technology Data Exchange (ETDEWEB)

    Miller, James Christopher [Los Alamos National Laboratory; Rennie, John Alan [Los Alamos National Laboratory; Toevs, James Waldo [Los Alamos National Laboratory; Wallace, Darrin J. [Los Alamos National Laboratory; Abhold, Mark Edward [Los Alamos National Laboratory

    2015-07-13

    The introduction points out that radiation backgrounds fluctuate across very short distances: factors include geology, soil composition, altitude, building structures, topography, and other manmade structures; and asphalt and concrete can vary significantly over short distances. Brief descriptions are given of the detection system, experimental setup, and background variation measurements. It is concluded that positive and negative gradients can greatly reduce the detection sensitivity of an MDS: negative gradients create opportunities for false negatives (nondetection), and positive gradients create a potentially unacceptable FAR (above 1%); the location of use for mobile detection is important to understand; spectroscopic systems provide more information for screening out false alarms and may be preferred for mobile use; and mobile monitor testing at LANL accounts for expected variations in the background.

  17. Vertebrate radiations of the Jehol Biota and their environmental background

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhonghe

    2004-01-01

    @@ Significant progress has been made in recent years in the studies of various groups of the Jehol Biota, particularly concerning the origin of birds and their flight as well as the evolution of Early Cretaceous birds, dinosaurs, mammals, insects and flowering plants[1-5]. As a result, the Jehol Biota has become well known to both the scientific community and the public. The studies on the Jehol Biota also revealed the patterns and processes of the evolutionary radiations of many major groups of Early Cretaceous animals and plants, such as the earliest known radiation of angiosperms and birds, early differentiation of mammals and many Cretaceous dinosaurian groups. Notably, the radiations of the Jehol vertebrates share some similar patterns attributable to the particular environmental background. For instance, the Jehol vertebrate radiations are highlighted by the presence of abundant arboreal adaptations and herbivorous forms, thus closely linked to the forest environments. In addition, the differentiation of habitats and diets is also characteristic of the evolutionary radiations of pterosaurs, dinosaurs, birds and mammals in the Jehol Biota.

  18. Health effects in residents of high background radiation regions

    International Nuclear Information System (INIS)

    Studies carried out in various countries and by the World Health Organization on health effects of exposure of populations to high levels of natural background radiation result in observations of different significance. There are indications of changes in chromosome aberration rate; Down's syndrome has been observed to be possibly related to radiation exposure; malignant neoplasms in bone apparently correspond to high concentrations of 226Ra in drinking water. Although various researchers have looked for them, effects have not been demonstrated regarding cancer mortality (other than malignant neoplasms involving bone), gross congenital abnormalities, fertility index, growth and development, hereditary disease (other than the possibility of Down's syndrome), infant mortality, longevity, multiple births, sex ratio, or spontaneous abortion rate. On the basis of reported data clear quantitative conception of the risk of low-level radiation from natural sources could not be developed and feasibility studies of further epidemiological programmes should be organized. The possibility of reducing the collective population dose from natural sources could be further explored and a basis for necessary legal action on establishment of standards for possible sources of natural radiation, such as building materials, fertilizers, natural gas and water, might be developed. (author)

  19. Radiative corrections in QED in a Lorentz violating background1

    International Nuclear Information System (INIS)

    Radiative corrections in Lorentz violating extensions of QED have received considerable attention in the last years. In this talk I will address the case of fermions coupled to a constant background axial-vector and analise both classical and quantum aspects which prove to be relevant for the consistence of the theory. The modification of the mass-shell conditions in the free theory allows to determine bounds on the fermions' momenta which in turns determines the domain of integration for radiative corrections. We consider this to render the theory free of ambiguities, rather than formal arguments which may lack foundation in this context. Also, the appearance of an anomalous loss of gauge invariance and the role of finite temperature are discussed.

  20. Cosmic Rays Induced Background Radiation on Board of Commercial Flights

    CERN Document Server

    Pinilla, S; Núñez, L A

    2015-01-01

    The aim of this work is to determine the total integrated flux of cosmic radiation which a commercial aircraft is exposed to along specific flight trajectories. To study the radiation background during a flight and its modulation by effects such as altitude, latitude, exposure time and transient magnetospheric events, we perform simulations based on Magnetocosmics and CORSIKA codes, the former designed to calculate the geomagnetic effects on cosmic rays propagation and the latter allows us to simulate the development of extended air showers in the atmosphere. In this first work, by considering the total flux of cosmic rays from 5 GeV to 1 PeV, we obtained the expected integrated flux of secondary particles on board of a commercial airplane during the Bogot\\'a-Buenos Aires trip by point-to-point numerical integration.

  1. Background radiation at Ooty in Nilgiri district of Tamil Nadu

    International Nuclear Information System (INIS)

    The systematic study of background radiation and the distribution of radionuclides in the environment of Ooty in the Nilgiri district of Tamil Nadu was undertaken. Soil samples were collected and detailed analysis for their radioactivity content by gamma ray spectrometry was carried out. The average activity of 232Th, 238U and 40K was estimated from the photo peaks. The thorium to uranium ratio was also found out and the mean value of this ratio was 1.876 with mean deviation 1.964. The analysis also revealed that the thorium concentration was 4.4 times higher than that of world average value. Uranium concentration was higher by a factor of 1.7. However, the concentration of potassium was much lesser than that of world average. An attempt was made to compare the dose calculated from total activity with that measured by environmental radiation dosimeter and the results are given. (author). 11 refs., 1 tab

  2. Evaluation of background ionising radiation levels within Gwagwalada town, Abuja

    International Nuclear Information System (INIS)

    The background ionising radiation levels within Gwagwalada Town, Abuja has been carried out using Atomtex 1117M Radiation Monitor. Readings were taken in twelve different locations. Twenty different readings were taken at each location and the mean equivalent dose rate was used to calculate the annual equivalent dose rate. A total of 240 measurements were taken across the 12 locations in the study Area. It was observed that the average dose equivalent varied from 0.105±0.008 μSv/h to 0.114±0.015μSv/h with a mean of 0.109±0.013 μSv/h. The mean value from Ungwan Bassa shows the highest equivalent dose rate while the equivalent dose rate from Phase 3 was the lowest. Ungwan Dodo, Ungwan Gwari recorded the second and third highest in-situ gamma radiation of 0.113±0.013 μSv/h and 0.112±0.012 μSv/h respectively. The result shows that the entire equivalent dose rates of all the locations were below the value of the Standard Background Radiation of 0.133 μSv/h. The study also revealed that the average annual equivalent dose rate is 0.192±0.005 mSv/y which is lower than the value of 1.0 mSv/yr averaged over five consecutive years according to the dose limit recommended by the International Commission on Radiological Protection (ICRP).

  3. UV background radiation, dust, and gas at high galactic latitude

    International Nuclear Information System (INIS)

    A new analysis of the UV background radiation measurements obtained with the ELZ instrument on board the D2B-Aura satellite is performed at high galactic latitudes (mod(b)>=300) in two bandpasses centered at 1690 A and 2200 A. Correlations of the UV brightnesses with dust tracers are found; the scattering phase function of dust can be derived. Among regions exhibiting a UV flux in excess over the average correlation, an insight is given on the Eridanus region known as a hot spot in soft X-rays. (Auth.)

  4. Search for Linear Polarization of the Cosmic Background Radiation

    Science.gov (United States)

    Lubin, P. M.; Smoot, G. F.

    1978-10-01

    We present preliminary measurements of the linear polarization of the cosmic microwave background (3 deg K blackbody) radiation. These ground-based measurements are made at 9 mm wavelength. We find no evidence for linear polarization, and set an upper limit for a polarized component of 0.8 m deg K with a 95% confidence level. This implies that the present rate of expansion of the Universe is isotropic to one part in 10{sup 6}, assuming no re-ionization of the primordial plasma after recombination

  5. Anisotropies of Cosmic Background Radiation from a Local Collapse

    OpenAIRE

    Wu, Xiang-Ping; Fang, Li-Zhi

    1993-01-01

    We present an exact solution of the anisotropies of cosmic background radiation (CBR) from a local collapse described by a spherical over-dense region embedded in a flat universe, with the emphasis on the relationship between the dipole $(\\Delta {\\sf T}/{\\sf T})_d$ and the quadrupole $(\\Delta {\\sf T}/{\\sf T})_q$ anisotropy. This result has been used to examine the kinematic quadrupole correction $(\\Delta {\\sf T}/{\\sf T})_q=(\\Delta {\\sf T}/{\\sf T})_d^2/2$, which is usually applied to remove th...

  6. Radiative emission of neutrino pair free of quantum electrodynamic backgrounds

    International Nuclear Information System (INIS)

    A scheme of quantum electrodynamic (QED) background-free radiative emission of a neutrino pair (RENP) is proposed in order to achieve precision determination of neutrino properties so far not accessible. The important point for the background rejection is the fact that the dispersion relation between the wave vector along the propagating direction in the wave guide (and in a photonic-crystal-type fiber) and the frequency is modified by a discretized non-vanishing effective mass. This effective mass acts as a cutoff of allowed frequencies, and one may select the RENP photon energy region free of all macro-coherently amplified QED processes by choosing the cutoff larger than the mass of neutrinos

  7. Large-Angular-Scale Anisotropy in the Cosmic Background Radiation

    Science.gov (United States)

    Gorenstein, M. V.; Smoot, G. F.

    1980-05-01

    We report the results of an extended series of airborne measurements of large-angular-scale anisotropy in the 3 K cosmic background radiation. Observations were carried out with a dual-antenna microwave radiometer operating at 33 GHz (.089 cm wavelength) flown on board a U-2 aircraft to 20 km altitude. In eleven flights, between December 1976 and May 1978, the radiometer measured differential intensity between pairs of directions distributed over most of the northern hemisphere with an rms sensitivity of 47 mK Hz{sup 1�}. The measurements how clear evidence of anisotropy that is readily interpreted as due to the solar motion relative to the sources of the radiation. The anisotropy is well fit by a first order spherical harmonic of amplitude 360{+ or -}50km sec{sup -1} toward the direction 11.2{+ or -}0.5 hours of right ascension and 19 {+ or -}8 degrees declination. A simultaneous fit to a combined hypotheses of dipole and quadrupole angular distributions places a 1 mK limit on the amplitude of most components of quadrupole anisotropy with 90% confidence. Additional analysis places a 0.5 mK limit on uncorrelated fluctuations (sky-roughness) in the 3 K background on an angular scale of the antenna beam width, about 7 degrees.

  8. An investigation of gamma background radiation in Hamadan province, Iran

    International Nuclear Information System (INIS)

    The general population, everywhere in the world is exposed to a small dose of ionising radiation from natural sources. Stochastic effects such as cancer and genetic disorders are caused when living creatures are exposed to low doses. In Iran, it is measured in some cities, especially in high-background areas such as Ramsar, but so far there is no measurement in the Hamadan province. Hamadan is located in the west of Iran. Measurements were performed using a RDS-110 survey meter, CaSO4:Dy thermoluminescence dosimetries (TLDs) and a Harshaw 4000 TLD reader. To estimate the dose rate outdoors, four stations along the main directions (north, south, west and east) and one in the town centre were selected. Mean annual X and gamma equivalent dose in Hamadan province are 1.12±0.22 and 1.66±0.07 mSv, which related to RDS-110 survey meter and TLDs measurements, respectively. The TLDs and RDS-110 results are representative of the external photon radiation doses for the selected monitoring locations and for those locations for the hours during which the measurements were taken, respectively. Maximum and minimum of external photon radiation doses are related to Hamadan and Kaboudar-Ahang towns, respectively. According to the results of the study, it seems that the annual X and gamma equivalent dose in Hamadan province exceeded the global mean external exposure amounts by the UNSCEAR, and further studies are needed to measure internal exposures to determine the total environmental radiation level in Hamadan province. (authors)

  9. Far Infrared Spectrometry of the Cosmic Background Radiation

    Science.gov (United States)

    Mather, J. C.

    1974-01-01

    I describe two experiments to measure the cosmic background radiation near 1 mm wavelength. The first was a ground-based search for spectral lines, made with a Fabry-Perot interferometer and an InSb detector. The second is a measurement of the spectrum from 3 to 18 cm{sup -1}, made with a balloon-borne Fourier transform spectrometer. It is a polarizing Michelson interferometer, cooled in liquid helium, and operated with a germanium bolometer. I give the theory of operation, construction details, and experimental results. The first experiment was successfully completed but the second suffered equipment malfunction on its first flight. I describe the theory of Fourier transformations and give a new understanding of convolutional phase correction computations. I discuss for infrared bolometer calibration procedures, and tabulate test results on nine detectors. I describe methods of improving bolometer sensitivity with immersion optics and with conductive film blackening.

  10. Cosmic Background Radiation and `ether-drift' experiments

    CERN Document Server

    Consoli, M; Rapisarda, A

    2016-01-01

    `Ether-drift' experiments have played a crucial role for the origin of relativity. Though, a recent re-analysis shows that those original measurements where light was still propagating in gaseous systems, differently from the modern experiments in vacuum and in solid dielectrics, indicate a small universal anisotropy which is naturally interpreted in terms of a non-local thermal gradient. We argue that this could possibly be the effect, on weakly bound gaseous matter, of the temperature gradient due to the Earth's motion within the Cosmic Background Radiation (CBR). Therefore, a check with modern laser interferometers is needed to reproduce the conditions of those early measurements with today's much greater accuracy. We emphasize that an unambiguous confirmation of our interpretation would have far reaching consequences. For instance, it would also imply that all physical systems on the moving Earth are exposed to a tiny energy flow, an effect that, in principle, could induce forms of self-organization in ma...

  11. Characteristic angular scales in cosmic microwave background radiation

    International Nuclear Information System (INIS)

    We investigate the stochasticity in temperature fluctuations in the cosmic microwave background (CMB) radiation data from the Wilkinson Microwave Anisotropy Probe. We show that the angular fluctuation of the temperature is a Markov process with a Markov angular scale, Markov 1.01-0.07+0.09. We characterize the complexity of the CMB fluctuations by means of a Fokker-Planck or Langevin equation and measure the associated Kramers-Moyal coefficients for the fluctuating temperature field T(n-circumflex) and its increment, ΔT = T(n-circumflex1) - T(n-circumflex2). Through this method we show that temperature fluctuations in the CMB have fat tails compared to a Gaussian distribution. (author)

  12. On epidemiological studies of high background radiation areas

    International Nuclear Information System (INIS)

    Until recently, the epidemiological studies of high background radiation areas (HBRA) have 'received relatively little attention', and sometimes even ignored, e.g. UNSCEAR omitted the studies in Kerala from a table of epidemiological studies of radiation and cancer. Authoritative reports on the effects from ionizing radiation such as those from the National Research Council, UNSCEAR, and ICRP instead rely on other sources of information - most notably the A-bomb survivor cohort, medically irradiated cohorts, cohorts of miners exposed to high levels of radon, and the residential radon case-control studies. No doubt this is because HBRA studies typically have had relatively large potential for bias and confounding, low statistical power, and limitations relating to dosimetry. However, great efforts have been made recently to improve HBRA studies, particularly in Kerala and the Yuangjiang area of China. It is anticipated that some of these studies may be able to provide important direct information on health effects from chronic low-dose radiation exposures, a primary concern for radiation protection. In fact, the width of 90% confidence intervals for ERR/Gy reported for incidence from the Kerala study (-0.58, 0.46), and mortality in Yangjiang (-0.67, 0.69), is already comparable to that for some prominent studies of low-dose rate health effects such as of incidence in the Techa River Cohort (0.3, 1.9) and of mortality in the 15-Country Nuclear Workers Study (0.27, 1.80). However, it should be stressed that these intervals do not account for non-sampling sources of uncertainty such as errors in dosimetry and residual confounding. This presentation will focus on ways to further improve HBRA studies around the world, with particular emphasis on the ones in India and China. This will include ways to increase statistical power - such as ways to combine information from different HBRA studies, and possible extensions of the studies such as those designed to better

  13. Epidemiological investigation in high background radiation areas of Yangjiang, China

    International Nuclear Information System (INIS)

    This investigation began in 1972. Various radiological measurements revealed that individual external exposure to the environmental gamma radiation in a high background radiation area (HBRA) is about three times higher than that in the nearby control area (CA). If the internal exposure is included, the averaged annual effective dose equivalents will be 5.4 mSv in HBRA, 2.0 mSv in CA respectively. About 80,000 inhabitants in each area whose families have lived there for two or more generations are being observed. About one million person-years in HBRA and in CA were observed for cancer mortality, and sex-, age- and site-specific cancer mortality were analyzed. Statistical analysis showed no difference either in mortality of all cancer or in immortality of leukemia between HBRA and CA. However, the cancer mortality of all cancer except leukemia for age group of 40-70 years was lower statistically in HBRA than that in CA. The total number of 31 kinds of hereditary diseases and congenital deformities in children below 12 years old between two areas were almost identical. However, the frequency of Down Syndrome in HBRA was statistically higher than that in CA. 16 refs, 2 figs, 29 tabs

  14. Investigation of background radiation and associated anomalies in Rifle, Colorado

    International Nuclear Information System (INIS)

    In addition to examining anomalies and establishing the background gamma exposure rate range, the study presents a formula to convert thousand counts per minute (kcpm) from a gamma scintillator to microroentgen per hour (μRh) for the Rifle region. Also, a method is presented to identify contaminated areas containing excess 226Ra, by using a GR-410 gamma spectrometer. This method is suggested to be applied to all property surveys in the Rifle area. The Wasatch Formation, which outcrops extensively in the Rifle area, was found to have a major influence on the background radiation. Varying potassium concentrations and naturally occurring uranium in this rock unit reveal varying gamma exposure rates. Examining RaTh ratios from laboratory analysis of soil samples or use of RaTh ratios from GR-410 gamma spectrometer readings on site allows discrimination between mill related contamination and naturally occuring radioactivity. Radioactive coal clinkers were found used as fill material throughout the Rifle region and have been determined to be a product of the mill and subject to remediation. Finally, windblown mill tailings contamination is addressed in some detail. Mill tailings redistributed from the Rifle uranium mill tailings piles by prevailing winds were detected extensively on vicinity properties in Rifle. Some radioactive components of the windblown tailings were found to have leached into the subsurface soil. The combination of Wasatch Formation, radioactive coal clinkers, and windblown tailings accounts for many of the anomalous gamma exposure rates observed by the radiological survey teams. 11 refs., 10 figs., 3 tabs

  15. Background Radiation Studies at LHCb Using Geant4

    CERN Document Server

    Daquino, G G; Folger, G

    2004-01-01

    This paper aims to describe the feasibility studies performed to evaluate the background radiation levels in the LHCb experiment with Geant4. LHCb is one of the experiments that will operate at the LHC (Large Hadron Collider) under construction at CERN. The simulation toolkit Geant4 has been used to model the interactions of particles with the detector. Geant4 is a software toolkit developed and maintained by a world-wide collaboration of physicists and computer scientists. The principal monitored distributions in this study are the dose and the fluence of certain particles in specific locations of the experiment. The dose is defined as the energy delivered in a volume per unit of the volume mass, while the fluence is defined as the number of particles passing through a surface per unit of area. Energy spectra need also to be evaluated to take into account the energy distribution of these particles, since specific problems in the electronics can be caused by particles of certain energies. For ...

  16. A background radiation survey along the transcontinental railway in Australia

    International Nuclear Information System (INIS)

    This article reports a survey, carried out during a period from October 31 to November 3, 1994 in Australia, as well as some basic techniques of train-borne measurements for estimating outdoor gamma-ray dose rates. Surface rock and bedrock data are presented for convenience for geological analysis. Cosmic-ray dose rates estimated from atmospheric pressure data are also presented for researchers who are interested in total background radiation dose rates. It was found that gamma levels can be high in the western area. The dose rate data were based on the shielding correction factor evaluated at platforms in many stations. To confirm the validity of this method, the data from train-borne surveys in central Japan were compared with the present Australian data. There were, to some extent, correlations between them. The present study suggests that the train-borne measurements are useful for surveying wide area in a short time with an error of about 20%. (N.K.)

  17. Background radiation studies at LHCb using Geant4

    CERN Document Server

    Daquino, Giuseppe Giovanni; Folger, Günter

    2006-01-01

    Preliminary results of simulation studies performed to evaluate the background radiation levels in the LHCb experiment are presented in the paper. LHCb is one of the experiments that will operate at the LHC (Large Hadron Collider) under construction at CERN. The simulation toolkit Geant4 has been used to model the interactions of particles with the detector. Geant4 is a software toolkit developed and maintained by a world-wide collaboration of physicists and computer scientists. The principal monitored distributions in this study are the dose and fluence of certain particles in specific locations of the experiment. Energy spectra need also to be evaluated in order to take into account the energy distribution of these particles, since specific problems in the electronics can be raised by particles of certain energies. To this purpose, we need: 1) Tallying doses and fluences in Geant4. 2) These quantities are generally calculated on a plane or a cylindrical surface that should not interfere with the real geomet...

  18. A Cosmic Microwave Background Radiation Polarimeter Using Superconducting Bearings

    CERN Document Server

    Hanany, S; Johnson, B; Jones, T; Hull, J R; Ma, K B

    2003-01-01

    Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured the coefficient of friction as a function of several parameters including temperature between 15 and 80 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm, and ambient pressure between 10^{-7} and 1 torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.

  19. Cosmic background radiation spectral distortion and radiative decays of relic neutral particles

    International Nuclear Information System (INIS)

    The recently observed excess of photons on a short wavelength side of the peak of a cosmic background radiation spectrum can be described by radiative decays of relic neutral particles. The lifetime and mass of a decaying particle must satisfy the following conditions: 2x109 s14 s, 0.4 eV-9-8x10-8) μb, and the interaction of new particles with the usual matter must be rather strong. The generalization of the standard SU(3)xSU(2)xU(1) model is presented which includes new particles with the desired properties. 18 refs.; 3 figs.; 2 tabs

  20. Radiative QCD backgrounds to exclusive H→b anti b production: radiation from the screening gluon

    International Nuclear Information System (INIS)

    Central exclusive Higgs boson production, pp→p+H+p, at the LHC can provide an important complementary contribution to the comprehensive study of the Higgs sector in a remarkably clean topology. The b anti b Higgs decay mode is especially attractive, and for certain BSM scenarios may even become the discovery channel. Obvious requirements for the success of such exclusive measurements are strongly suppressed and controllable backgrounds. One potential source of background comes from additional gluon radiation which leads to a three-jet b anti bg final state. We perform an explicit calculation of the subprocesses gg→q anti qg, gg→ggg in the case of 'internal' gluon radiation from the spectator, t-channel screening gluon, when the two incoming active t-channel gluons form a color octet. We find that the overall contribution of this source of background is orders of magnitude lower than that caused by the main irreducible background resulting from the ggPP→b anti b subprocess. Therefore, this background contribution can be safely neglected. (orig.)

  1. Radiation dose in the high background radiation area in Kerala, India.

    Science.gov (United States)

    Christa, E P; Jojo, P J; Vaidyan, V K; Anilkumar, S; Eappen, K P

    2012-03-01

    A systematic radiological survey has been carried out in the region of high-background radiation area in Kollam district of Kerala to define the natural gamma-radiation levels. One hundred and forty seven soil samples from high-background radiation areas and five samples from normal background region were collected as per standard sampling procedures and were analysed for (238)U, (232)Th and (40)K by gamma-ray spectroscopy. External gamma dose rates at all sampling locations were also measured using a survey meter. The activities of (238)U, (232)Th and (40)K was found to vary from 17 to 3081 Bq kg(-1), 54 to 11976 Bq kg(-1) and BDL (67.4 Bq kg(-1)) to 216 Bq kg(-1), respectively, in the study area. Such heterogeneous distribution of radionuclides in the region may be attributed to the deposition phenomenon of beach sand soil in the region. Radium equivalent activities were found high in several locations. External gamma dose rates estimated from the levels of radionuclides in soil had a range from 49 to 9244 nGy h(-1). The result of gamma dose rate measured at the sampling sites using survey meter showed an excellent correlation with dose rates computed from the natural radionuclides estimated from the soil samples. PMID:21515614

  2. Scientific and organizational background with regard to occupational radiation protection

    International Nuclear Information System (INIS)

    The starting point of the joint European health policy is the 1957 Euratom Treaty, which puts great emphasis on the protection of workers and the general public against dangers arising from ionizing radiation. New radiation protection legislation is driven by scientific developments, by experience with former legislation or by identification of regulatory gaps. Additionally, new legislation has been initiated after identification of changes in social and industrial structures and after the Chernobyl accident. To ensure a harmonized and sound operational implementation of the new radiation protection requirements, close contact is kept between the European Commission departments active in the radiation protection field and those responsible for operational radiation protection in competent authorities as well as in the working field. This process also identifies the need for new regulations. The European radiation protection policy contributed significantly to the achievements, providing for the present high standards of radiological protection of workers and the general public within the European Union. However, the radiological protection issue cannot be seen as isolated and detached from other developments in our society, which is confronted with major problems, most of which appear from the fact that the different sectors in our society progress and develop at different speeds. This leads to confusion and therefore the subject of radiation protection in industry, education, research and medicine is a multidisciplinary initiative involving different interest groups and specialized services. This activity will continue to be of importance for the next century. (author)

  3. Calculating the background radiation in the vicinity of the beam catchers of the ELBE radiation source

    International Nuclear Information System (INIS)

    The ELBE radiation sources comprises beam catchers in the experimenting sites which absorb the primary electron beam as well as the generated secondary radiation. The beam catcher consists of an ultrapure graphite absorber enclosed in a water-cooled stainless steel shell. Background radiation is shielded by iron, lead and heavy concrete. The beam parameters and the position of the beam catchers differ between experimenting sites. In order to determine the dose dependence of photon and neutron fluence and the dose equivalent at the cooling shell of the beam catcher, simulations were carried out using the FLUKA code. Radiation energies of 20 MeV and 50 MeV and electron fluxes of 1 mA were considered. The spatial and energetic distributions of the dose rate equivalent provide a basis for dimensioning of the radiation shields. The calculated distributions of the energy dose rate in the beam catcher serve as a basis for assessing thermal loads on materials and for designing the cooling system. (orig.)

  4. Experiences from studies of leukemia, background radiation and other factors

    International Nuclear Information System (INIS)

    Ionizing radiation seems to induce myeloid leukemia of the acute and chronic type, and also acute lymphatic leukemia but not chronic lymphatic leukemia. The effects of low dose radiation in this context as well as for other malignancies, are currently a matter of controversy. On the basis of literary data the carcinogenic effect, and in particular the leukemia inducing effect, of low dose irradiation is discussed. It is concluded that only further studies in the low dose range can create a definite basis for a risk assessment with regard to ionizing radiation. The risk estimates obtained may not necessarily reflect an initiating effect of ionizing radiation, but could involve late stage effects exerted over time. However, such possibilities have so far achieved little attention

  5. Regular observation of natural background radiation in high school using a ventilated case for meteorological instruments

    International Nuclear Information System (INIS)

    There are many examples of the measurement of natural background radiation in schools. Most schools in Japan have ventilated cases for taking meteorological measurements, but they are rarely used. We measure natural background radiation using a ventilated case as part of chemistry club activities. Figures 2 and 3 to 6 show the natural background radiation in various rooms, and in the ventilated case, respectively. I propose that there are some advantages to using ventilated meteorological station cases for the measurement of natural background radiation. (author)

  6. Human exposure to high natural background radiation: what can it teach us about radiation risks?

    Energy Technology Data Exchange (ETDEWEB)

    Hendry, Jolyon H; Sohrabi, Mehdi; Burkart, Werner [Department of Nuclear Sciences and Applications, International Atomic Energy Agency, Vienna (Austria); Simon, Steven L [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD (United States); Wojcik, Andrzej [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Cardis, Elisabeth [Centre for Research in Environmental Epidemiology (CREAL), Municipal Institute of Medical Research (IMIM-Hospital del Mar) and CIBER Epidemiologia y Salud Publica - CIBERESP, Barcelona (Spain); Laurier, Dominique; Tirmarche, Margot [Radiobiology and Epidemiology Department, Radiological and Human Health Division, Institute for Radiological Protection and Nuclear Safety, Fontenay-aux-Roses (France); Hayata, Isamu [National Institute of Radiological Sciences, Chiba (Japan)], E-mail: jhendry2002uk@yahoo.com

    2009-06-01

    Natural radiation is the major source of human exposure to ionising radiation, and its largest contributing component to effective dose arises from inhalation of {sup 222}Rn and its radioactive progeny. However, despite extensive knowledge of radiation risks gained through epidemiologic investigations and mechanistic considerations, the health effects of chronic low-level radiation exposure are still poorly understood. The present paper reviews the possible contribution of studies of populations living in high natural background radiation (HNBR) areas (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China), including radon-prone areas, to low dose risk estimation. Much of the direct information about risk related to HNBR comes from case-control studies of radon and lung cancer, which provide convincing evidence of an association between long-term protracted radiation exposures in the general population and disease incidence. The success of these studies is mainly due to the careful organ dose reconstruction (with relatively high doses to the lung), and to the fact that large-scale collaborative studies have been conducted to maximise the statistical power and to ensure the systematic collection of information on potential confounding factors. In contrast, studies in other (non-radon) HNBR areas have provided little information, relying mainly on ecological designs and very rough effective dose categorisations. Recent steps taken in China and India to establish cohorts for follow-up and to conduct nested case-control studies may provide useful information about risks in the future, provided that careful organ dose reconstruction is possible and information is collected on potential confounding factors.

  7. Radiation Background and Attenuation Model Validation and Development

    Energy Technology Data Exchange (ETDEWEB)

    Peplow, Douglas E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Santiago, Claudio P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-08-05

    This report describes the initial results of a study being conducted as part of the Urban Search Planning Tool project. The study is comparing the Urban Scene Simulator (USS), a one-dimensional (1D) radiation transport model developed at LLNL, with the three-dimensional (3D) radiation transport model from ORNL using the MCNP, SCALE/ORIGEN and SCALE/MAVRIC simulation codes. In this study, we have analyzed the differences between the two approaches at every step, from source term representation, to estimating flux and detector count rates at a fixed distance from a simple surface (slab), and at points throughout more complex 3D scenes.

  8. Cosmological Production of Vector Bosons and Cosmic Microwave Background Radiation

    CERN Document Server

    Blaschke, D B; Gusev, A A; Pervushin, V N; Proskurin, D P

    2004-01-01

    The intensive cosmological creation of vector W, Z- bosons in the cosmological model with the relative units is considered. Field theoretical models are studied, which predict that the CMB radiation and the baryon matter in the universe can be products of decay and annihilation processes of these primordial bosons.

  9. Rain-induced increase in background radiation detected by Radiation Portal Monitors

    International Nuclear Information System (INIS)

    A complete understanding of both the steady state and transient background measured by Radiation Portal Monitors (RPMs) is essential to predictable system performance, as well as maximization of detection sensitivity. To facilitate this understanding, a test bed for the study of natural background in RPMs has been established at the Oak Ridge National Laboratory. This work was performed in support of the Second Line of Defense Program's mission to enhance partner country capability to deter, detect, and interdict the illicit movement of special nuclear material. In the present work, transient increases in gamma-ray counting rates in RPMs due to rain are investigated. The increase in background activity associated with rain, which has been well documented in the field of environmental radioactivity, originates primarily from the wet-deposition of two radioactive daughters of 222Rn, namely, 214Pb and 214Bi. In this study, rainfall rates recorded by a co-located weather station are compared with RPM count rates and high-purity germanium spectra. The data verify that these radionuclides are responsible for the largest environmental background fluctuations in RPMs. Analytical expressions for the detector response function in Poly-Vinyl Toluene have been derived. Effects on system performance and potential mitigation strategies are discussed. - Highlights: • Analytical response-function of Radiation Portal Monitors to wet-deposition of radioactive radon-daughters. • Spectral proof of constituent radio-isotopes in rain (using HPGe), directly correlated with RPM response. • Direct proof of the independence of RPM rain-response and atmospheric pressure. • Future study will be able to estimate global/seasonal activity-density of rain from RPM responses. • Future automation of analysis will include filters based on characteristic RPM response

  10. Microbiology of the surface water samples in the high background radiation areas of Ramsar, Iran

    International Nuclear Information System (INIS)

    Residents of high background radiation areas of Ramsar have lived in these areas for many generations and received radiation doses much higher than the dose limit recommended by ICRP for radiation workers. The radioactivity of the high background radiation areas of Ramsar is reported to be due to 226Ra and its decay products, which have been brought to the surface by the waters of hot springs. Over the past years the department has focused on different aspects of the health effects of the elevated levels of natural radiation in Ramsar. This study was aimed to perform a preliminary investigation on the bioeffects of exposure to elevated levels of natural radiation on the microbiology of surface water samples. Water samples were collected from surface water streams in Talesh Mahalleh district, Ramsar as well as a nearby area with normal levels of background radiation. Only two strains of bacteria, that is, Providencia stuartii and Shimwellia blattae, could be isolated from the water samples collected from high background radiation areas, while seven strains (Escherichia coli, Enterobacter asburiae, Klebsiella pneumoniae, Shigella dysenteriae, Buttiauxella agerstis, Tatumella punctuata and Raoultella ornithinolytica) were isolated from the water samples collected from normal background radiation areas. All the bacteria isolated from water samples of high and normal background radiation areas were sensitive to ultraviolet radiation, heat, betadine, alcohol, and deconex. Although other investigators have reported that bacteria isolated from hot springs show radioresistance, the results reported here do not reveal any adaptive response. (author)

  11. Detecting a non-Gaussian stochastic background of gravitational radiation

    CERN Document Server

    Drasco, S; Drasco, Steve; Flanagan, Eanna E.

    2002-01-01

    We derive a detection method for a stochastic background of gravitational waves produced by events where the ratio of the average time between events to the average duration of an event is large. Such a signal would sound something like popcorn popping. Our derivation is based on the somewhat unrealistic assumption that the duration of an event is smaller than the detector time resolution.

  12. Detecting a non-Gaussian stochastic background of gravitational radiation

    OpenAIRE

    Drasco, Steve; Flanagan, Eanna E.

    2001-01-01

    We derive a detection method for a stochastic background of gravitational waves produced by events where the ratio of the average time between events to the average duration of an event is large. Such a signal would sound something like popcorn popping. Our derivation is based on the somewhat unrealistic assumption that the duration of an event is smaller than the detector time resolution.

  13. Hawking's radiation in non-stationary rotating de Sitter background

    CERN Document Server

    Ibohal, Ng; 10.1007/s10509-011-0606-0

    2011-01-01

    Hawking's radiation effect of Klein-Gordon scalar field, Dirac particles and Maxwell's electromagnetic field in the non-stationary rotating de Sitter cosmological space-time is investigated by using a method of generalized tortoise co-ordinates transformation. The locations and the temperatures of the cosmological horizons of the non-stationary rotating de Sitter model are derived. It is found that the locations and the temperatures of the rotating cosmological model depend not only on the time but also on the angle. The stress-energy regularization techniques are applied to the two dimensional analog of the de Sitter metrics and the calculated stress-energy tensor contains the thermal radiation effect.

  14. Significance of epidemiological and cytogenetic studies on high background radiation area residents

    International Nuclear Information System (INIS)

    Some area in the world are known as background levels of radiation are 3-5 times higher than the world average. The studies in high background area (HBRA) residents provide important direct information on the biological and health effects of chronic low dose rate radiation. (author)

  15. Position sensitive detection of neutrons in high radiation background field

    Czech Academy of Sciences Publication Activity Database

    Vavřík, Daniel; Jakůbek, Jan; Vacík, Jiří; Pospíšil, S.

    2014-01-01

    Roč. 85, č. 1 (2014), s. 013304. ISSN 0034-6748 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0060; GA ČR(CZ) GBP108/12/G108; GA TA ČR(CZ) TA01010237 Institutional support: RVO:68378297 ; RVO:61389005 Keywords : neutrons * pattern recognition * position sensitive detectors * radiation detectors * silicon detectors Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering; BG - Nuclear, Atomic and Molecular Physics, Colliders (UJF-V) Impact factor: 1.614, year: 2014 http://scitation.aip.org/content/aip/journal/rsi/85/1/10.1063/1.4862478

  16. Evaluation of Background Ionization Radiation Level in some selected Dumpsites in Delta State, Nigeria

    OpenAIRE

    Avwiri, O Gregory; Emmanuel, O Esi

    2014-01-01

    This paper reports on the evaluation of background Ionization radiation level (BIR) in some selected Dumpsites in Uvwie, Udu and Ughelli North Local government area of Delta State, Nigeria. Background ionization radiation measurements were carried out in five Dumpsites. An in- situ measurement was done using a well calibrated nuclear radiation meters Radalert-100 and a geographical positioning system (GPS). Readings were taken once in a week for one month in ten different locations within eac...

  17. Dark energy and the cosmic microwave background radiation

    Science.gov (United States)

    Dodelson, S.; Knox, L.

    2000-01-01

    We find that current cosmic microwave background anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation. This result is robust to editing of data sets, and variation of other cosmological parameters (totaling seven, including a cosmological constant). Other lines of argument indicate that the energy density of nonrelativistic matter is much less than critical. Together, these results are evidence, independent of supernovae data, for dark energy in the Universe.

  18. Fast shutter for low background radiation environments at SPR III

    International Nuclear Information System (INIS)

    A fast shutter system has been developed and used to isolate experiments from the radiation emitted after the main pulse of the Sandia Pulse Reactor, SPR 3. In about 15 ms the system moves a massive 20 kg shield in front of the beam port aperture in the facility shield wall. A second gravity-driven shutter is dropped into place in about 200 ms. The total attenuation achieved in the beam intensity is about a factor of one hundred. The shutter assembly was used, along with a sensitive detection system, to observe the gamma ray flux emitted by various materials activated by the neutron beam at levels nine orders of magnitude smaller than the gamma flux level at the target during the reactor pulse

  19. How does radiative feedback from a UV background impact reionization?

    CERN Document Server

    Sobacchi, Emanuele

    2013-01-01

    An ionizing UV background (UVB) inhibits gas accretion and photo-evaporates gas from the shallow potential wells of small, dwarf galaxies. During cosmological reionization, this effect can result in negative feedback: suppressing star-formation inside HII regions, thus impeding their continued growth. It is difficult to model this process, given the enormous range of scales involved. We tackle this problem using a tiered approach: combining parameterized results from single-halo collapse simulations with large-scale models of reionization. In the resulting reionization models, the ionizing emissivity of galaxies depends on the local values of the reionization redshift and the UVB intensity. We present a physically-motivated analytic expression for the average minimum mass of star-forming galaxies, which can be readily used in modeling galaxy formation. We find that UVB feedback: (i) delays the end stages of reionization by less than 0.5 in redshift; (ii) results in a more uniform distribution of HII regions, ...

  20. Modeling Background Radiation in our Environment Using Geochemical Data

    Energy Technology Data Exchange (ETDEWEB)

    Malchow, Russell L.; Marsac, Kara [University of Nevada, Las Vegas; Burnley, Pamela [University of Nevada, Las Vegas; Hausrath, Elisabeth [Uniiversity of Nevada, Las Vegas; Haber, Daniel [University of Nevada, Las Vegas; Adcock, Christopher [University of Nevada, Las Vegas

    2015-02-01

    Radiation occurs naturally in bedrock and soil. Gamma rays are released from the decay of the radioactive isotopes K, U, and Th. Gamma rays observed at the surface come from the first 30 cm of rock and soil. The energy of gamma rays is specific to each isotope, allowing identification. For this research, data was collected from national databases, private companies, scientific literature, and field work. Data points were then evaluated for self-consistency. A model was created by converting concentrations of U, K, and Th for each rock and soil unit into a ground exposure rate using the following equation: D=1.32 K+ 0.548 U+ 0.272 Th. The first objective of this research was to compare the original Aerial Measurement System gamma ray survey to results produced by the model. The second objective was to improve the method and learn the constraints of the model. Future work will include sample data analysis from field work with a goal of improving the geochemical model.

  1. Polymerconcrete for Radiation Background Shielding of Detectors at Hadron Colliders

    Science.gov (United States)

    Astapov, A. A.; Zaitsev, L. N.; Zaitsev, S. L.

    1997-05-01

    New shielding material - polymerconcrete with density 1.2dots 3.6 g\\cdotcm-3 and H, Li or B contents (4dots6.6)\\cdot10^22 H\\cdotcm-3, 1.3\\cdot10^22 Li\\cdotcm-3 or 3.3\\cdot10^21 B\\cdotcm-3, respectively, is developed. Granular polythene, lead powder, lithium salts or boron carbide are cemented by the special cement, dissolved in the liquid polymer. Material samples have lower limits of the resistance to compression 42 MPa, the resistance to rupture 6 MPa and the dynamic coefficient of elasticity 10^3 MPa. Radiation resistance, tested at the reactor IBR-2 and accelerators at JINR, IHEP and ITEP is 10^3 Mrad at 10 krad\\cdots-1 and 1 Mrad at 10 rad\\cdots-1. It is enough for a future colliders. Our experimental results demonstrate, that the induced radioactivity levels for the polymerconcrete are lower than ones for a ordinary concretes. It is shown that density 3.2dots 3.6 g\\cdotcm-3 of a steel-concrete composition is optimum to get the minimum shielding thickness and cost. Polymerconcrete can be used as bricks or for the filling in any forms. It is suggesting to use this material instead CH2 and Pb for shielding of the setups D0 and CDF at the Tevatron and CMS, ATLAS, ALICE at the LHC.

  2. Mapping the exposure of the Brazilian population to natural background radiation - cosmic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rochedo, Elaine R.R., E-mail: elaine@ird.gov.br [Instituto de Radioprotecao e Dosimetria (lRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Salles, Krause C.S.; Prado, Nadya M.C., E-mail: krausesalles@yahoo.com.br, E-mail: nadya@ime.ib.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The main objective of this work is to statically and graphically describe the exposure of the Brazilian population to natural background radiation. in this stage, doses due to cosmic rays is being assessed based on sea level dose rates, corrected by latitude and altitude, according to the model recommended by UNSCEAR. In this work, the doses were estimated for ali Brazilian municipalities with more than 100.000 inhabitants. The 253 municipalities selected for this study include about 52% of the Brazilian population. Average dose rate was estimated to be about 50 n Sv/h with a variation coefficient of 31%. The estimated doses have shown a strong influence of altitude on dose rates, with a correlation coefficient of 0,998 for ao exponential fit. This result confirms previous studies that show a large effect of the altitude 00 exposure from cosmic radiation. Considering the same occupation and shielding conditions used by UNSCEAR as global averages, average annual dose was estimated to be 0,37 (0,24 - 0,76) mSv/y, very close to UNSCEAR worldwide average of 0,38 (0,3 - 1,0) mSv/y. (author)

  3. Effects of deprivation of background environmental radiation on cultured human cells

    International Nuclear Information System (INIS)

    In this paper we present results from an experiment aimed at investigating whether living cells are influenced by background ionizing radiation. Parallel human cell cultures were set-up in two separate laboratories and maintained for several months under identical conditions but for a 80 x different level of background ionizing radiation. Periodically, the cell cultures were monitored for the onset of divergences in biochemical behavior, using two distinct cellular biology assays, namely micronuclei induction and activity of enzymes implicated in the management of oxidative stress. To reveal any subtle modifications, responses were also amplified by subjecting cell cultures to acute stress induced by exposure to moderately high doses of ionizing radiation. Compared to reference radiation background conditions, cultures maintained in a reduced background radiation environment handled the consequences of acute stress with diminished efficacy.

  4. Pre operational background radiation monitoring around Kudankulam Nuclear Power Project site - a decade long experience

    International Nuclear Information System (INIS)

    Pre-operational environmental background radiation monitoring around nuclear power plants is very important to understand baseline values existing in the site and also to identify any hot spots of naturally occurring high background radiation areas and their sources. These baseline measurements will act as a benchmark for future comparison after the reactors go into operation. The radiation measurements are continued during the operational phase of the plant and the results are compared to see whether there is any impact of the operation of the plant on the environment. A comprehensive background radiation monitoring plan has been in vogue at site from 2004 to meet this objective. This paper describes the different monitoring strategies adopted around Kudankulam Nuclear Power Project site and throws light on the pre operational background radiation levels in the environment

  5. Self-amplifying Hawking radiation and its background: a numerical study

    CERN Document Server

    Steinhauer, Jeff

    2016-01-01

    We numerically study an analogue black hole with two horizons with similar parameters to a recent experiment. We find that the Hawking radiation exists on a background which contains a density oscillation, a zero-frequency ripple. The Hawking radiation evolves from spontaneous to self-amplifying, while the background ripple grows steadily with no qualitative change. It is seen that the self-amplifying Hawking radiation has a non-zero frequency. The background ripple appears even before the inner horizon is created, in contrast to predictions. This work is in agreement with the recent observation of self-amplifying Hawking radiation, and explains some of the features seen. In contrast to recent works, our study differentiates between the Hawking radiation observed, and the evolution of the background.

  6. Evaluation of the natural background radiation in City Sopron

    Energy Technology Data Exchange (ETDEWEB)

    Spaits, T. [West Hungary Univ., Institute of Forestry Mechanics (Hungary); Divos, F. [West Hungary Univ., National Radiation Control System - Sopron Unit (Hungary); Kavasi, N. [Veszprem Univ., Dept. of Radiochemistry (Hungary); Boka, Z. [West Hungary Univ., Dept. of Geodetics and Remote Sensing (Hungary)

    2006-07-01

    In the Postgraduate School of the Faculty of Forestry of the University of West Hungary a project with the topic Research of natural radioactive isotopes in our built and natural environs is being run. Preparing this map is an organic part of this PhD research. The measurements are being made in Sopron city and in its next surroundings, trying to estimate, which dose of radiation a citizen of Sopron is exposed, according to his age and lifestyle. The measurements completely cover the built-up area of Sopron, moreover they exceed the confines, so thus they provide information about the natural areas in the vicinity of the city. In figures, the detection carried out in an area of 24 square kilometres, working with a grid mesh of 200 metres. A sodium-iodide detector was used. We have faced several anomalies while mapping. These are the following: On Main Square (Foter), Ursulin Square (Orsolya ter), Paulites Square (Palosok tere, where a higher dose can be measured, due to granite cobbles, used to cover the pavements of the squares and streets. This was confirmed by the gamma spectrometric examination of the granite stones. In these areas, a triple of the mean dose-rate of 70-90 n Sv/h in Sopron was detected. The highest values of 400 n Sv/h were detected in the cinder-covered car-park of the paint store in Koszegi Street. The total gamma activity concentration of the cinder used in the car-park was nearly 2000 Bq/kg. A triple to a quadruple of the natural level was detected in the vicinity of the chimney of the former thermal power plant and the brick factory. The detection was carried out in four directions with raising range starting by the chimneys, which has spectacularly shown, that the sedimentation of the aerosols can be tracked is a function of distance. The measurements have also shown, that there is a significant difference between dose-levels of the natural areas beyond the eastern and western edge of the city, which can be explained with the different

  7. Evaluation of the natural background radiation in City Sopron

    International Nuclear Information System (INIS)

    In the Postgraduate School of the Faculty of Forestry of the University of West Hungary a project with the topic Research of natural radioactive isotopes in our built and natural environs is being run. Preparing this map is an organic part of this PhD research. The measurements are being made in Sopron city and in its next surroundings, trying to estimate, which dose of radiation a citizen of Sopron is exposed, according to his age and lifestyle. The measurements completely cover the built-up area of Sopron, moreover they exceed the confines, so thus they provide information about the natural areas in the vicinity of the city. In figures, the detection carried out in an area of 24 square kilometres, working with a grid mesh of 200 metres. A sodium-iodide detector was used. We have faced several anomalies while mapping. These are the following: On Main Square (Foter), Ursulin Square (Orsolya ter), Paulites Square (Palosok tere, where a higher dose can be measured, due to granite cobbles, used to cover the pavements of the squares and streets. This was confirmed by the gamma spectrometric examination of the granite stones. In these areas, a triple of the mean dose-rate of 70-90 n Sv/h in Sopron was detected. The highest values of 400 n Sv/h were detected in the cinder-covered car-park of the paint store in Koszegi Street. The total gamma activity concentration of the cinder used in the car-park was nearly 2000 Bq/kg. A triple to a quadruple of the natural level was detected in the vicinity of the chimney of the former thermal power plant and the brick factory. The detection was carried out in four directions with raising range starting by the chimneys, which has spectacularly shown, that the sedimentation of the aerosols can be tracked is a function of distance. The measurements have also shown, that there is a significant difference between dose-levels of the natural areas beyond the eastern and western edge of the city, which can be explained with the different

  8. Investigation of the possibility of reducing the radiation background of meteorological-radar reflector antennas

    Science.gov (United States)

    Pavlov, V. F.; Sakhatskii, V. D.; Iurchak, B. S.

    1980-12-01

    The radiation background of directional antennas is a negative factor that reduces the reliability of received information, decreases electromagnetic compatibility, and noise immunity, and has a detrimental effect on biological tissues. The present study examines possible ways to reduce the radiation background of meteorological-radar reflector antennas by using radio-absorbing materials. Requirements for such materials are outlined, and a material is selected that satisfies these requirements. Devices for the reduction of the radiation background have been developed which can significantly reduce the side emission without any deterioration of useful characteristics.

  9. Distribution of background radiation and radioactive materials in Aomori Prefecture

    International Nuclear Information System (INIS)

    The first commercial nuclear fuel reprocessing plant in Japan is now being constructed in Rokkasho Village, Aomori Prefecture and large amounts of Pu and U will be treated in the plant. Therefore, we made a plan for getting background levels of Pu, U and other related radionuclides in soil samples around the plant beginning with plowed fields, then rice fields, orchards, forests and un-cultivated fields, ie a different field type, year by year. This is the first report of results for plowed fields. The soil samples were collected at 13 plowed fields in Rokkasho and three control sites in Tohoku Town, Hachinohe City and Hirosaki City. Five core samples of 75 mmφ, down to approximately 1 m deep, were taken in each field in 2001. Three to five layers were distinguished by a visual inspection, and the same layers from each of the five cores were combined. When depth profiles of layers for some cores were different from those of others, those cores were separately treated. Concentrations of 137Cs and 210Pb in the sample were measured with γ-ray spectrometers using Ge detectors. Pu, U and Th in the soil samples were analyzed with a ICP-MS. Since fields under yam (Dioscorea babatus) cultivation are dug up to approximately 1 m deep at harvesting, depth profiles of fallout radionuclides were heavily disturbed for most fields in Rokkasho. The mean and standard deviation of inventory of Pu (239+240Pu) in three fields where have not cultivated yam in Rokkasho was 120 ± 50 Bq m-2. The mean inventory was similar to that in Hachinohe City. However, the inventory was approximately a half of that in Hirosaki City. The Pu concentrations very well correlated with 137Cs (r=0.97), and the ratio of Pu/137Cs was 0.037 ± 0.007, which is a typical value for global fallout. This showed that the movements of Pu and 137Cs in soil were similar in spite of heavy soil disturbance, and the ratio could be used for distinguishing the plant Pu from global fallout. Since the concentrations of

  10. The proportion of thyroid cancers in the Japanese atomic bomb survivors associated with natural background radiation

    International Nuclear Information System (INIS)

    Generalised absolute and relative risk models (with adjustment to the excess absolute risk for time since exposure and age at exposure, and with adjustment to the excess relative risk for age at exposure) are fitted to the Japanese atomic bomb survivor thyroid cancer incidence data followed up over the period 1958-87, taking account of natural background radiation. Thyroid cancers associated with natural background radiation and atomic bomb radiation are overwhelmingly accounted for by exposure at young ages. Over 50% of the excess cases associated with either the atomic bomb radiation or natural background radiation are linked to exposures under the age of 20, irrespective of the assumed risk model or natural background dose rate. The excess risk is overwhelmingly concentrated among females, again irrespective of the assumed model or natural background dose rate. Depending on the assumed natural background dose rate (in the range 0.5-2.0 mSv/year) between 17.3 and 32.0% of the thyroid cancer in this cohort may be associated with natural background radiation if an absolute risk model applies; between 4.2 and 17.1% of the thyroid cancers may be associated with natural background radiation if the relative risk model applies. The proportion of the thyroid tumours attributed to the atomic bomb radiation is between 21.1 and 22.0% for the absolute risk model, and is between 18.7 and 19.1% for the relative risk model, in both cases irrespective of the assumed background radiation dose. In particular, these proportions are not very different from the proportions calculated when fitting models that do not take account of natural background radiation, namely 22.0% for the absolute risk model and 18.6% for the relative risk model. The proportion of thyroid cancers accounted for by natural background radiation progressively increases with attained age, from 0.3% of cancers among those under the age of 15 to 30.5% for those over the age of 60, assuming that the absolute risk

  11. Telomere Length in Human Adults and High Level Natural Background Radiation

    OpenAIRE

    Birajalaxmi Das; Divyalakshmi Saini; Seshadri, M

    2009-01-01

    BACKGROUND: Telomere length is considered as a biomarker of aging, stress, cancer. It has been associated with many chronic diseases such as hypertension and diabetes. Although, telomere shortening due to ionizing radiation has been reported in vitro, no in vivo data is available on natural background radiation and its effect on telomere length. METHODOLOGY/PRINCIPAL FINDINGS: The present investigation is an attempt to determine the telomere length among human adults residing in high level na...

  12. THE HIGH BACKGROUND RADIATION AREA IN RAMSAR IRAN: GEOLOGY, NORM, BIOLOGY, LNT, AND POSSIBLE REGULATORY FUN

    Energy Technology Data Exchange (ETDEWEB)

    Karam, P. A.

    2002-02-25

    The city of Ramsar Iran hosts some of the highest natural radiation levels on earth, and over 2000 people are exposed to radiation doses ranging from 1 to 26 rem per year. Curiously, inhabitants of this region seem to have no greater incidence of cancer than those in neighboring areas of normal background radiation levels, and preliminary studies suggest their blood cells experience fewer induced chromosomal abnormalities when exposed to 150 rem ''challenge'' doses of radiation than do the blood cells of their neighbors. This paper will briefly describe the unique geology that gives Ramsar its extraordinarily high background radiation levels. It will then summarize the studies performed to date and will conclude by suggesting ways to incorporate these findings (if they are borne out by further testing) into future radiation protection standards.

  13. Radiobiological analysis of region with higher radiation background. The effect of the background on the isomorphism of some enzymes

    International Nuclear Information System (INIS)

    An attempt is made to establish the the time when the prolong impact of slightly increased radiation background get over the compensator mechanisms of living systems. The object of investigation was the ecosystem of the Bay of Wromos (Black Sea, BG) and its surroundings where the flotation slack from an uranium mine was disposed. radioactivity. The following radiobiological picture of the site is obtained according to measurements performed: the alpha-activity of the beach sands is higher than one of the slack and is different in plants; the beta-activity is higher compared to controls in all samples investigated; the gamma spectra show high concentration of the members of U-238 and Th-232 series. The biological effect provoked by this heightened radiation background is studied by means of the isoenzymes as indicators of changes on molecular level. The isoenzyme spectra of lactate dehydrogenase and butyrol dehydrogenase is studied by vertical electrophoresis. The following species are tested: Tettigonia candata charp, Galliptumus italicus, Grillus campestris and Lumbicus terrestrial. An increase in activity and quantity of enzymes as well as changes of their isoenzyme spectra is observed. Calliptumus italicus could be used as a bio indicator of contamination, as it show better separation of the LDH and BDH-isoforms of LDH and BDH, and is more wide-spread. The increase in activity and quantity of some isoenzyme fractions in the conditions of this experiment is one of the possible mechanisms for increase in radioresistance of the living systems. 3 tabs., 2 figs., 8 refs

  14. The background of external γ radiation in the proportional counters in SAGE experiment

    International Nuclear Information System (INIS)

    The influence of external γ radiation on the process of 71Ge-decay counting in proportional counters in SAGE experiment of solar neutrino flux measurement is examined. One determines the systematic error of SAGE result, connected with radon decays inside the air volume surrounding the counters, and the background counting rate of proportional counters from γ radiation of passive and active shield

  15. Spectrum of the cosmic background radiation: early and recent measurements from the White Mountain Research Station

    International Nuclear Information System (INIS)

    The White Mountain Research Station has provided a support facility at a high, dry, radio-quiet site for measurements that have established the blackbody character of the cosmic microwave background radiation. This finding has confirmed the interpretation of the radiation as a relic of the primeval fireball and helped to establish the hot Big Bang theory as the standard cosmological model

  16. Background radiation and childhood leukemia: A nationwide register-based case-control study.

    Science.gov (United States)

    Nikkilä, Atte; Erme, Sini; Arvela, Hannu; Holmgren, Olli; Raitanen, Jani; Lohi, Olli; Auvinen, Anssi

    2016-11-01

    High doses of ionizing radiation are an established cause of childhood leukemia. However, substantial uncertainty remains about the effect of low doses of radiation, including background radiation and potential differences between genetic subgroups of leukemia have rarely been explored. We investigated the effect of the background gamma radiation on childhood leukemia using a nationwide register-based case-control study. For each of the 1,093 cases, three age- and gender matched controls were selected (N = 3,279). Conditional logistic regression analyses were adjusted for confounding by Down syndrome, birth weight (large for gestational age), and maternal smoking. Complete residential histories and previously collected survey data of the background gamma radiation in Finland were used to assess the exposure of the study subjects to indoor and outdoor gamma radiation. Overall, background gamma radiation showed a non-significant association with the OR of childhood leukemia (OR 1.01, 95% CI 0.97, 1.05 for 10 nSv/h increase in average equivalent dose rate to red bone marrow). In subgroup analyses, age group 2-childhood leukemia, particularly at age 2-<7 years. Our findings suggest a larger effect of radiation on leukemia with high hyperpdiploidy than other subgroups, but this result requires further confirmation. PMID:27405274

  17. Cosmic background radiation anisotropy in an open inflation, cold dark matter cosmogony

    Science.gov (United States)

    Kamionkowski, Marc; Ratra, Bharat; Spergel, David N.; Sugiyama, Naoshi

    1994-01-01

    We compute the cosmic background radiation anisotropy, produced by energy-density fluctuations generated during an early epoch of inflation, in an open cosmological model based on the cold dark matter scenario. At Omega(sub 0) is approximately 0.3-0.4, the Cosmic Background Explorer (COBE) normalized open model appears to be consistent with most observations.

  18. Stable type chromosome aberrations in the residents of the high background radiation area in China

    International Nuclear Information System (INIS)

    Chromosome translocations were analyzed by chromosome painting techniques using No.1, 2 and 4 whole chromosome painting probes to examine the effect of high-level natural radiation on the frequencies of chromosome translocations in human peripheral lymphocytes. The subjects were 5 children and 13 old men from the high background radiation area and 6 children and 11 old men from the control area. Children had lesser translocations and smaller variation compared with the old men. The frequency of translocations among the old subjects varied widely from person to person. There is no difference of the frequency of chromosome translocations between high background radiation area and control area. No effect of high-level natural background radiation on the frequencies of stable chromosome translocation was detected

  19. Geographically determined dependencies in the value of the constant natural radiation gamma-background

    International Nuclear Information System (INIS)

    The problem of the assessment of the influence of natural gamma background changes on the population is discussed. It is considered that the populations in different geographic regions have adapted by evolution mechanisms to the respective unchanged (without human activities) radiation background. The background limits for each area form the 'radiation comfortable zone' which varies very much for the different geographic areas. Leaving the 'comfortable zone' leads to a triggering of adaptive mechanisms in the population including the natural selection in order to reach an equilibrium. Thus, the radiation impact exceeding the 'comfortable zone' is expected to cause harm for a part of the population which is preliminarily burden or uncapable to adapt. From this point of view the increased morbidity due to radiation factor in those cases remains hidden. As a conclusion it is pointed out that the proposed increase of the annual dose for the population might result with harmful consequences for the whole human population

  20. DNDO Report: Predicting Solar Modulation Potentials for Modeling Cosmic Background Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Behne, Patrick Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-08

    The modeling of the detectability of special nuclear material (SNM) at ports and border crossings requires accurate knowledge of the background radiation at those locations. Background radiation originates from two main sources, cosmic and terrestrial. Cosmic background is produced by high-energy galactic cosmic rays (GCR) entering the atmosphere inducing a cascade of particles that eventually impact the earth’s surface. The solar modulation potential represents one of the primary inputs to modeling cosmic background radiation. Usosokin et al. formally define solar modulation potential as “the mean energy loss [per unit charge] of a cosmic ray particle inside the heliosphere…” Modulation potential, a function of elevation, location, and time, shares an inverse relationship with cosmic background radiation. As a result, radiation detector thresholds require adjustment to account for differing background levels, caused partly by differing solar modulations. Failure to do so can result in higher rates of false positives and failed detection of SNM for low and high levels of solar modulation potential, respectively. This study focuses on solar modulation’s time dependence and seeks the best method to predict modulation for future dates using Python. To address the task of predicting future solar modulation, we utilize both non-linear least squares sinusoidal curve fitting and cubic spline interpolation. This material will be published in transactions of the ANS winter meeting of November, 2016.

  1. Experimental study of variations in background radiation and the effect on Nuclear Car Wash sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Church, J; Slaughter, D; Norman, E; Asztalos, S; Biltoft, P

    2007-02-07

    Error rates in a cargo screening system such as the Nuclear Car Wash [1-7] depend on the standard deviation of the background radiation count rate. Because the Nuclear Car Wash is an active interrogation technique, the radiation signal for fissile material must be detected above a background count rate consisting of cosmic, ambient, and neutron-activated radiations. It was suggested previously [1,6] that the Corresponding negative repercussions for the sensitivity of the system were shown. Therefore, to assure the most accurate estimation of the variation, experiments have been performed to quantify components of the actual variance in the background count rate, including variations in generator power, irradiation time, and container contents. The background variance is determined by these experiments to be a factor of 2 smaller than values assumed in previous analyses, resulting in substantially improved projections of system performance for the Nuclear Car Wash.

  2. The evolution of the earth's background radiation field over the past four billion years

    International Nuclear Information System (INIS)

    It seems likely that life has evolved under an evolving background radiation field. The radiation dose from the earth itself has changed over geologic time as the crust of the earth has become enriched in radioactive elements and as those elements subsequently decayed away. The radiation dose from biologic potassium has steadily decreased with time according to the law of radioactive decay. Because of these two effects, it seems likely that early life was exposed to nearly ten times current radiation dose rates. In addition to these sources, cosmic and cosmogenic sources may have periodically raised radiation dose rates to very high levels at times in the past. These sources of radiation exposure are not well understood at present, but are the subject of ongoing research. Modern organisms may be more resistant to the adverse effects of radiation because mutation repair mechanisms evolved under higher radiation levels. This may help to shed some light on the current controversy regarding the biological effects of exposure to low levels of ionizing radiation, or it may simply help us to understand why cancer is primarily a disease of the elderly rather than the middle-aged. In addition, changing radiation levels over geologic time may help to reconcile molecular models of evolution with what is currently known from the fossil record. It may also be that this reconciliation can be used to validate the radiation dose rate models described above. Only time and further research will tell

  3. Investigation on Down's syndrome in the children living in high background radiation area

    International Nuclear Information System (INIS)

    After the survey in 1975 and 1979 of Down's syndrome in the children living in high background radiation area, we made a follow-up investigation in 1985 and 1986. All the obtained data are analysed. 25258 children in high background radiation area were examined and 22 children with Down's syndrome were identified, the morbidity rate being 0.87%. 21837 children in control area were examined and four children with Down's syndrome were identified, the morbidity being 0.18%. There was a statistically significant difference between the two groups. It was noted that the occurrence of Down's syndrome was related to the maternal age but there was no evidence suggesting a close relationship between high background radiation and the development of Down's syndrome

  4. Study of background radiation along the east coast of Tamil Nadu- a preliminary report

    International Nuclear Information System (INIS)

    A detailed study of natural background radiation along the east coast of Tamil Nadu has been undertaken. Thirty three sites were selected along the coast. Ambient gamma radiation levels were measured both on shore and inland at each site and these are presented and discussed in this paper. Soil, terrestrial and marine matrices have been collected and are being subjected to gamma ray spectral analysis. Preliminary results from the spectral analysis of soil samples reveal that the higher radiation levels, wherever observed, are due to the presence of monazite content. The complete analysis and measurements of the samples from the various matrices are being taken up and a more comprehensive report of the distribution of natural background radiation along the coast would facilitate a deeper study. (author). 2 refs., 2 figs

  5. Background of external γ radiation in the proportional counters of the SAGE experiment

    International Nuclear Information System (INIS)

    The effect of external γ radiation on the process of counting 71Ge decays in the proportional counters of the SAGE experiment measuring the solar-neutrino flux is considered. The systematic uncertainty in the SAGE result due to radon decays inside the air volume surrounding the counters is estimated. The background counting rate in the proportional counters that is caused by γ radiation from the enclosing shield is also determined

  6. On the radiative and thermodynamic properties of the Cosmic Microwave Background radiation using COBE FIRAS instrument data

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Use formulas to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density in the finite range of frequencies are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at the temperature T = 2.728 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant are calculated. In the case of the dipole spectrum, the constants a and the Stefan-Bol...

  7. Investigation and analysis of etiology of down's syndrome in children of high background radiation area

    International Nuclear Information System (INIS)

    In order to find out what caused the differences in incidences of Down's syndrome between the children in high background radiation area and those in control area, investigation and analysis were carried ou in 5 aspects based on the original data and the information from the previous survey. These are: the incidences of congenital malformations in normal areas, the age distribution of children examined, the maternal age, the dates of birth of afflicted children, and the radiation exposure of mothers. The results suggested that the higher incidence of Down's syndrome in high background area might be related to the materal age. Further studies are needed to arrive at a conclusion

  8. Background radiation in two locations in Deaf Smith and Swisher Counties within the Palo Duro Basin

    International Nuclear Information System (INIS)

    Data on external background radiation doses resulting from cosmic, terrestrial, and fallout sources and on concentrations of radioactivity in environmental media are presented and discussed. Doses to individuals located at the approximate centers of two locations in Texas, one in Deaf Smith County and the other in Swisher County, are given, as are the population doses to people residing within 50 miles of each of the approximate centers. No adjustments have been made for the effects of buildings on radiation doses - that is, the shielding from external radiation afforded by the buildings and radiation from building materials are not accounted for. Concentrations of radioactivity in air, water, and milk in the region are also given. Because of the lack of specific information on background radiation at the locations, the external-dose rates to people and the radioactivity levels in environmental media for the region have been taken from the literature. A background radiation survey will be conducted in the Palo Duro Basin to obtain additional data. 26 references, 3 figures, 15 tables

  9. Correlation between regional oncological mortality and natural radiation background in the CSR

    International Nuclear Information System (INIS)

    On the basis of published geological data (maps) an attempt was made to correlate the regional distribution of oncological mortality with the dose rate of the natural radiation background in the Czech Socialist Republic. No relationship was observed between the two parameters in the whole area of the CSR; for districts with an increased dose rate of the background or with high mortality the statistical relationship proved an inverse relationship: the higher the background dose rate the lower the oncological mortality and vice versa. (author). 3 figs., 1 tab., 22 refs

  10. The evolution of the earth's background radiation level over geologic time

    International Nuclear Information System (INIS)

    This paper examines the evolution of the background radiation field in which primitive organisms evolved in terms of internal dose (from internal 40K) and external geologic dose (from gamma emitters in the crust of the earth), and how this may relate to dose-response in modern organisms. (author)

  11. Chromosomal analysis by G-banding techinque in youngsters of high background radiation area

    International Nuclear Information System (INIS)

    It was demonstrated that the frequency of chromosome aberrations of peripheral lymphocytes in inhabitants of the high background radiation area was higher than that in people of the control area. In this study, the chromosome aberrations in inhabitants of both areas were analysed by means of G-banding techique in an efforf to improve the detection of stable aberrations. Chromosome aberrations were studied in blood lymphocytes from 34 inhabitnts of the high background radiation area, and from 40 controls of normal background radiation area. Seabright's trypsin G-banding technique with minor modification was employed. In the result, in the high background group 55 aberrations were found in 1711 banded metaphases with a frequency of 3.21/100 cells, while in the control group only 39 aberrations were observed in 2006 metaphases, showing a frequency of 1.94/100 cells. Obviously, the frequency in the former group was significantly higher than that in the latter. On analysis of the types of aberrations, translocations and deletions accounted for approximately 85% of the total aberrations. There were 86 breaks found by G-banding in the high background group and 67 breaks in the control. A statistical comparison of observed and expected values showed that the distributions of chromosome breaks in both groups were nonrandom. When individual chromosomes were compared separately, it was found that the observed values of the breaks of chromosomes 1, 2 and 8 were higher than the expected

  12. Investigation of background radiation levels and geologic unit profiles in Durango, Colorado

    International Nuclear Information System (INIS)

    As part of the Uranium Mill Tailings Remedial Action (UMTRA) Project, Oak Ridge National Laboratory (ORNL) has performed radiological surveys on 435 vicinity properties (VPs) in the Durango area. This study was undertaken to establish the background radiation levels and geologic unit profiles in the Durango VP area. During the months of May through June, 1986, extensive radiometric measurements and surface soil samples were collected in the Durango VP area by personnel from ORNL's Grand Junction Office. A majority of the Durango VP surveys were conducted at sites underlain by Quaternary alluvium, older Quaternary gravels, and Cretaceous Lewis and Mancos shales. These four geologic units were selected to be evaluated. The data indicated no formation anomalies and established regional background radiation levels. Durango background radionuclide concentrations in surface soil were determined to be 20.3 ± 3.4 pCi/g for 40K, 1.6 ± 0.5 pCi/g for 226Ra, and 1.2 ± 0.3 pCi/g for 232Th. The Durango background gamma exposure rate was found to be 16.5 ± 1.3 μR/h. Average gamma spectral count rate measurements for 40K, 226Ra and 232Th were determined to be 553, 150, and 98 counts per minute (cpm), respectively. Geologic unit profiles and Durango background radiation measurements are presented and compared with other areas. 19 refs., 15 figs., 5 tabs

  13. Thyroid nodularity and chromosome aberrations among women in areas of high background radiation in China

    International Nuclear Information System (INIS)

    Thyroid nodularity following continuous low-dose radiation exposure in China was determined in 1,001 women aged 50-65 years who resided in areas of high background radiation (330 mR/yr) their entire lives, and in 1,005 comparison subjects exposed to normal levels of radiation (114 mR/yr). Cumulative doses to the thyroid were estimated to be of the order of 14 cGy and 5 cGy, respectively. Personal interviews and physical examinations were conducted, and measurements were made of serum thyroid hormone levels, urinary iodine concentrations, and chromosome aberrations in circulating lymphocytes. For all nodular disease, the prevalences in the high background and control areas were 9.5% and 9.3%, respectively. For single nodules, the prevalences were 7.4% in the high background area and 6.6% in the control area (prevalence ratio = 1.13; 95% confidence interval = 0.82-1.55). There were no differences found in serum levels of thyroid hormones. Women in the high background region, however, had significantly lower concentrations of urinary iodine and significantly higher frequencies of stable and unstable chromosome aberrations. Increased intake of allium vegetables such as garlic and onions was associated with a decreased risk of nodular disease, which seems consistent with experimental studies suggesting that allium compounds can inhibit tumor growth and proliferation. The prevalence of mild diffuse goiter was higher in the high background radiation region, perhaps related to a low dietary intake of iodine. These data suggest that continuous exposure to low-level radiation throughout life is unlikely to appreciably increase the risk of thyroid cancer. However, such exposure may cause chromosomal damage

  14. Profiles of comprehensive dose to population in the high background radiation area in Chhattrapur, Odisha, India

    International Nuclear Information System (INIS)

    A study of the profiles of radiation dose due to natural radioactivity to the populations inhabiting in the High Background Radiation Area (HBRA) of the monazite bearing region in Odisha has been carried out by radiation monitoring of twenty four villages in this region. Comprehensive effective dose was computed taking all the path routes of exposure into consideration; the average effective dose was 4.7±1.0 mSv/y which ranged between 1.4±0.2-6.3±1.3 mSv/y. The contributions of terrestrial radiation, inhalation of radon, thoron progenies and ingestion of food and water to the total dose was 51%, 28% and 13%, respectively. (author)

  15. A review of the studies on the high background radiation areas of the world

    International Nuclear Information System (INIS)

    The most important places among the well documented high background radiation areas (HBRA) of the world inhabited by sizable populations are : Guarapari (Brazil), Yangjiang (China), Chavara and Manavalakkurichy (India), and Ramsar (Iran). While the source of the high background radiation is monazite deposits in the first three cases, radium in soil/water and radon in air are the sources of high background radiation in Ramsar. In India, there are quite a few monazite placer deposits along its long coastal line: Ullal (Karnataka), Chavara (Kerala), Manavalakkurichy and Kalpakkam (Tamilnadu), and Chatrapur (Orissa). During the last three decades many investigations have been carried out in these areas covering various aspects such as radiation dosimetry, biological effects, ecological effects, epidemiology etc. Reports, often vague and inconclusive, continue to appear in literature on topics like genetic effects, cancer risk, hormesis, radon dose estimates etc. A summary of all the important results reported so far, as well as some thoughts on possible future programmes in these areas are presented. (author). 7 refs., 1 tab., 1 fig

  16. Down's syndrome and related abnormalities in an area of high background radiation in coastal Kerala

    International Nuclear Information System (INIS)

    It is stated that in a coastal area of Kerala, Southern India, the background radiation is between 1500 and 3000 mR/yr, this being due to the presence of Th-containing monazite mineral in the soil. During an epidemiological study of modular lesions of the thyroid in this area an apparently high prevalence of Down's syndrome and other forms of severe mental retardation was observed. A house-to-house survey of relevant abnormalities in this area was made, and also in a comparable control area without high background radiation. The frequency of chromosome aberrations in a sample of the population in the study and control areas was also investigated. The observations support the view that radiation induces genetic anomalies occur with above average frequency in the population living in the area with high background radiation. Only gross abnormalities evident in clinical examination were recorded. The study and control populations were similar in age and sex structure and general sociologic conditions. Severe mental retardation was the commonest abnormality encountered, and 85% of the abnormalities detected in the study population were genetic in origin, compared with 56% in the control population. Prevalence of Down's syndrome was 0.93 per 1000 in the study population. (U.K.)

  17. Natural background radiation exposure in the western coastal villages of Tamil Nadu, India - a preliminary study

    International Nuclear Information System (INIS)

    External gamma radiation fields have been measured in eleven villages situated at the southern coastal peninsular India. The average fields in the villages range from 0.7 to 3.0 μGyh-1 at the outdoor environment. The ratio between the outdoor and indoor radiation field works out to 1.7. The sea beaches adjoining the villages show average radiation fields ranging from 0.5 to 20 μGyh-1. High outdoor occupancy of the inhabitants, extending 12 hours per day, related to occupation rest and recreation is observed in the area. Significant diurnal changes are seen in the concentrations of 220Rn progeny in the indoor and outdoor atmosphere. Based on the external gamma radiation fields, occupancy factors and internal exposures, total dose of the population at the natural high background radiation area (NHBRA) has been estimated. The per capita average exposure in the coastal villages from Midalam to Muttom works out to 17 mSv per year which is 3 times higher than the earlier reported value from the NHBRA at Chavara-Neendakara. Nearly 90% of the exposure is contributed by external gamma radiation. The NHBRA which is inhabited by nearly 1 lakh fishermen offers a unique population group for radiation dosimetry and epidemiological studies. (author)

  18. Impact of the Fukushima nuclear accident on background radiation doses measured by control dosimeters in Japan.

    Science.gov (United States)

    Romanyukha, Alexander; King, David L; Kennemur, Lisa K

    2012-05-01

    After the 9.0 magnitude earthquake and subsequent massive tsunami on 11 March 2011 in Japan, several reactors at the Fukushima Daiichi Nuclear Power Plant suffered severe damage. There was immediate participation of U.S. Navy vessels and other United States Department of Defense (DoD) teams that were already in the area at the time of the disaster or arrived shortly thereafter. The correct determination of occupational dose equivalent requires estimation of the background dose component measured by control dosimeters, which is subsequently subtracted from the total dose equivalent measured by personal dosimeters. The purpose of the control dosimeters is to determine the amount of radiation dose equivalent that has accumulated on the dosimeter from background or other non-occupational sources while they are in transit or being stored. Given the release of radioactive material and potential exposure to radiation from the Fukushima Daiichi Nuclear Power Plant and the process by which the U.S. Navy calculates occupational exposure to ionizing radiation, analysis of pre- and post-event control dosimeters is warranted. Several hundred historical dose records from the Naval Dosimetry Center (NDC) database were analyzed and compared with the post-accident dose equivalent data of control dosimeters. As result, it was shown that the dose contribution of the radiation and released radiological materials from the Fukushima nuclear accident to background radiation doses is less than 0.375 μSv d for shallow and deep photon dose equivalent. There is no measurable effect on neutron background exposure. The latter has at least two important conclusions. First, the NDC can use doses measured by control dosimeters at issuing sites in Japan for determination of personnel dose equivalents; second, the dose data from control dosimeters prior to and after the Fukushima accident may be used to assist in dose reconstruction of non-radiological (non-badged) personnel at these locations

  19. On the population of primordial star clusters in the presence of UV background radiation

    CERN Document Server

    MacIntyre, M A; Thomas, P A; Intyre, Michael A. Mac; Santoro, Fernando; Thomas, Peter A.

    2006-01-01

    We use the algorithm of Cole et al. (2000) to generate merger trees for the first star clusters in a Lambda CDM cosmology under an isotropic UV background radiation field, parametrized by J_21. We have investigated the problem in two ways: a global radiation background and local radiative feedback surrounding the first star clusters. Cooling in the first halos at high redshift is dominated by molecular hydrogen, H_2 - we call these Generation 1 objects. At lower redshift and higher virial temperature, T_vir > 10^4K, electron cooling dominates - we call these generation 2. Radiation fields act to photo-dissociate H_2, but also generate free electrons that can help to catalyse its production. At modest radiation levels, J_{21}/(1+z)^3 ~ 10^{-12}-10^{-7}, the nett effect is to enhance the formation of Generation 1 star-clusters. At higher fluxes the heating from photo-ionisation dominates and halts their production. With a realistic build-up of flux over time, the period of enhanced H_2 cooling is so fleeting as...

  20. Discussions on results of environmental background radiation level investigation for Tianwan Nuclear Power Plant

    International Nuclear Information System (INIS)

    The environmental background radiation level investigation surrounding Tianwan Nuclear Power Plant was conducted for 2 years by China Institute for Radiation Protection. The investigation results are all collected in this paper and discussions are made on some results, such as 90Sr and 3H contents in water bodies, 137Cs and 7Be contents in plant, 137Cs and 40K contents in animal and animal products, 137Cs contents in soil, plant and animal, as well as considerations in choosing indicating organism, etc. Main conclusions are presented as well. (author)

  1. Radionuclides and Radiation Indices of High Background Radiation Area in Chavara-Neendakara Placer Deposits (Kerala, India)

    OpenAIRE

    Mary Thomas Derin; Perumal Vijayagopal; Balasubramaniam Venkatraman; Ramesh Chandra Chaubey; Anilkumar Gopinathan

    2012-01-01

    The present paper describes a detailed study on the distribution of radionuclides along Chavara - Neendakara placer deposit, a high background radiation area (HBRA) along the Southwest coast of India (Kerala). Judged from our studies using HPGe gamma spectrometric detector, it becomes evident that Uranium ((238)U), Thorium ((232)Th) and Potassium ((40)K) are the major sources for radioactivity prevailing in the area. Our statistical analyses reveal the existence of a high positive correlation...

  2. Probing reionization with the cross power spectrum of 21 cm and near-infrared radiation backgrounds

    CERN Document Server

    Mao, Xiao-Chun

    2014-01-01

    The cross-correlation between the 21 cm emission from the high-redshift intergalactic medium and the near-infrared (NIR) background light from the high-redshift galaxies promises to be a powerful probe of cosmic reionization. In this paper, we investigate the cross power spectrum during the epoch of reionization. We employ an improved halo approach to derive the distribution of the density field and consider two stellar populations in the star formation model: metal-free stars and metal-poor stars. The reionization history is further generated to be consistent with the electron-scattering optical depth from cosmic microwave background measurements. Then the intensity of NIR background is estimated by collecting emission from stars in the first-light galaxies. On large scales, we find the 21 cm and NIR radiation backgrounds are positively correlated during the very early stages of reionization. However, these two radiation backgrounds quickly become anti-correlated as reionization proceeds. The maximum absolut...

  3. Biological consequences of increased natural radiation background for Microtus oeconomus Pall. populations

    Energy Technology Data Exchange (ETDEWEB)

    Kudyasheva, Alevtina G. [Radioecology Department, Institute of Biology, Komi Scientific Center, Ural Division RAS, 28 Kommunisticheskaya ul., Syktyvkar 167982, Komi Republic (Russian Federation); Shishkina, Ludmila N. [Emanuel Institute of Biochemical Physics RAS, Kosygina 4, Moscow 119991 (Russian Federation); Shevchenko, Oksana G. [Radioecology Department, Institute of Biology, Komi Scientific Center, Ural Division RAS, 28 Kommunisticheskaya ul., Syktyvkar 167982, Komi Republic (Russian Federation)], E-mail: shevchenko@ib.komisc.ru; Bashlykova, Ludmila A.; Zagorskaya, Nadezhda G. [Radioecology Department, Institute of Biology, Komi Scientific Center, Ural Division RAS, 28 Kommunisticheskaya ul., Syktyvkar 167982, Komi Republic (Russian Federation)

    2007-09-15

    The results of long-term investigations (1981-1999) on the state of Microtus oeconomus Pall. (tundra vole) population, living under the increased natural radiation background for a long time (for more than 100 generations), are presented. Population density dynamics, morphophysiological parameters, state of the lipid peroxidation regulatory system in different tissues and the cytogenetic effects in bone marrow cells of animals have been analyzed. It is shown that tundra voles from the studied radioactively contaminated areas differ from those on natural radiation background area for the parameters measured. The results of this long-term investigation show that qualitatively new sub-populations of tundra vole on these areas have evolved, which are able to survive in radioactively contaminated environment.

  4. Human response to high-background radiation environments on Earth and in space

    Science.gov (United States)

    Durante, M.; Manti, L.

    2008-09-01

    The main long-term objective of the space exploration program is the colonization of the planets of the Solar System. The high cosmic radiation equivalent dose rate represents an inescapable problem for the safe establishment of permanent human settlements on these planets. The unshielded equivalent dose rate on Mars ranges between 100 and 200 mSv/year, depending on the Solar cycle and altitude, and can reach values as high as 360 mSv/year on the Moon. The average annual effective dose on Earth is about 3 mSv, nearly 85% of which comes from natural background radiation, reduced to less than 1 mSv if man-made sources and the internal exposure to Rn daughters are excluded. However, some areas on Earth display anomalously high levels of background radiation, as is the case with thorium-rich monazite bearing sand deposits where values 200 400 times higher than the world average can be found. About 2% of the world’s population live above 3 km and receive a disproportionate 10% of the annual effective collective dose due to cosmic radiation, with a net contribution to effective dose by the neutron component which is 3 4 fold that at sea level. Thus far, epidemiological studies have failed to show any adverse health effects in the populations living in these terrestrial high-background radiation areas (HBRA), which provide an unique opportunity to study the health implications of an environment that, as closely as possibly achievable on Earth, resembles the chronic exposure of future space colonists to higher-than-normal levels of ionizing radiation. Chromosomal aberrations in the peripheral blood lymphocytes from the HBRA residents have been measured in several studies because chromosomal damage represents an early biomarker of cancer risk. Similar cytogenetic studies have been recently performed in a cohort of astronauts involved in single or repeated space flights over many years. The cytogenetic findings in populations exposed to high dose-rate background radiation

  5. On the Light Speed Anisotropy vs Cosmic Microwave Background Dipole: European Synchrotron Radiation Facility Measurements

    CERN Document Server

    Gurzadyan, V G; Kashin, A; Margarian, A T; Bartalini, O; Bellini, V; Castoldi, M; D'Angelo, A; Didelez, J P; Salvo, R D; Fantini, A; Gervino, G; Ghio, F; Girolami, B; Giusa, A; Guidal, M; Hourany, E; Knyazyan, S; Kouznetsov, V; Kunne, Ronald Alexander; Lapik, A; Levi-Sandri, P; Llères, A; Mehrabyan, S S; Moricciani, D; Nedorezov, V; Perrin, C; Rebreyend, D; Russo, G; Rudnev, N; Schärf, C; Sperduto, M L; Sutera, M C; Turinge, A

    2007-01-01

    The measurement of the Compton edge of the scattered electrons in GRAAL facility in European Synchrotron Radiation Facility (ESRF) in Grenoble with respect to the Cosmic Microwave Background dipole reveals up to 10 sigma variations larger than the statistical errors. We now show that the variations are not due to the frequency variations of the accelerator. The nature of Compton edge variations remains unclear, thus outlining the imperative of dedicated studies of light speed anisotropy.

  6. Review of cosmic background radiation spectrum measurements: limits on distortions, energy release, and cosmological processes

    International Nuclear Information System (INIS)

    This paper reviews the three major cosmic microwave background radiation (CMBR) spectrum measurement programs conducted and published since the last (XVII) IAU General Assembly. The results are consistent with a Planckian spectrum with temperature 2.72 +- 0.03 K spanning a wavelength range of 0.1 to 12 cm. Limits on possible distortions and implications are outlined. Ongoing and future measurements are discussed

  7. Cytogenetic studies on newborns from high level natural background radiation areas of Kerala coast, South India

    International Nuclear Information System (INIS)

    The human population residing in the monazite bearing high level natural background radiation (HLNBR) areas of Kerala, along the South-West coast of India provides unique opportunities of assessing directly in man, the health effects of chronic low-level radiation exposure. The per capita dose received by this population is nearly four times the normal background radiation level. While this is the average dose, the radiation levels prevailing in these HLNBR areas are in the range of 1 to over 35 mGy per year. Chromosomal aberration studies in the lymphocytes of newborns and adults from these areas have been in progress for two decades. So far, 4156 newborn babies from HLNBR and 7321 from normal background radiation (NBR) areas have been screened for the incidence of chromosomal aberrations (dicentrics and rings). The mean frequency of dicentrics and rings did not show any significant difference between the newborns in the control and the HLNBRA population. Assessment of the frequency of micronuclei in cytochalasin-B blocked binucleated lymphocytes of 49 newborns from control areas and 131 newborns from radioactive areas also showed similar values. While an age-dependent increase in chromosome aberration frequency was observed in the adult samples from control and the study areas, the regression analysis of the data indicated a marginally higher slope for the samples from HLNBRA. Karyotype anomalies recorded so far among the newborns have not revealed any significant difference in the incidence of numerical (including Down syndrome) and structural alterations between the control and the exposed populations. A noteworthy observation, herein reported for the first time from any HLNBR area is that there is no discernible increase in the incidence of micronuclei and chromosomal aberrations in the peripheral lymphocytes of newborn babies hailing from HLNBR areas, where their ancestral generations have lived for several hundreds of years. (author)

  8. Primordial Gravitational Waves and Rescattered Electromagnetic Radiation in the Cosmic Microwave Background

    CERN Document Server

    Kim, Dong-Hoon

    2016-01-01

    Understanding the interaction of primordial gravitational waves (GWs) with the Cosmic Microwave Background (CMB) plasma is important for observational cosmology. In this article, we provide an analysis of an effect apparently overlooked as yet. We consider a single free electric charge and suppose that it can be agitated by primordial GWs propagating through the CMB plasma, resulting in periodic, regular motion along particular directions. Light reflected by the charge will be partially polarized, and this will imprint a characteristic pattern on the CMB. We study this effect by considering a simple model in which anisotropic incident electromagnetic (EM) radiation is rescattered by a charge sitting in spacetime perturbed by GWs and becomes polarized. As the charge is driven to move along particular directions, we calculate its dipole moment to determine the leading-order rescattered EM radiation. The Stokes parameters of the rescattered radiation exhibit a net linear polarization. We investigate how this pol...

  9. Measurement of radioactivity in an elevated radiation background area of Western Ghats

    Directory of Open Access Journals (Sweden)

    Manigandan P.K.

    2014-01-01

    Full Text Available As part of monitoring the exposure of the general public to natural radioactivity, the activity concentration of naturally occurring radionuclides in soil samples in an elevated radiation background area of Western Ghats was determined using gamma-ray spectrometry. Average values of the activity concentration of radionuclides, outdoor terrestrial gamma dose rate, annual effective dose equivalent and radiation hazard indices from soil activity were estimated. The activity concentrations of 232Th and average outdoor terrestrial gamma dose rate were found to be higher than the world average, possibly affecting the Western Ghats environment in general. Therefore, radiological risks to the general population from ionizing radiation from the naturally occurring radionuclides in the soil are considered to be significant. How- ever, other radiological hazard indices were found to be within permissible limits.

  10. Background radiation and birth defects in seven prefectures in north Japan and in Ibaraki Prefecture

    International Nuclear Information System (INIS)

    Among 7 prefectures in north Japan, Niigata has the highest background radiation and Aomori the lowest. Foetal, neonatal, perinatal and infant death rates are, however, the lowest in Niigata and highest in Aomori. Vital statistics in 7 prefectures in north Japan and in Ibaraki were compared from 1960 to 1980. Death rates were decreased remarkably in 20 years in these prefectures as well as in Japan in general. If a linear correlation, y = a + bx is assumed between radiation dose x and death rate y, regression coefficient b is always negative in 6 cases (3 kinds of death rates in 2 test periods). Improvement in vital statistics is not due to the difference in radiation levels. (author)

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

    International Nuclear Information System (INIS)

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

  12. Cytogenetic investigation in a population living in the high background radiation area in China

    Energy Technology Data Exchange (ETDEWEB)

    Deqing, C.

    1980-04-01

    On the basis of the previous investigation, 24,000 metaphases of the lymphocytes of 120 inhabitants from Tongyou region, where the highest individual cummulative exposure per year of 372 mR in weighted average was recorded in the high background radiation area selected, have been analysed with the method recommended by WHO in 1973, in order to determine the extent of human chromosome aberrations induced by the high background radiation of various levels. The results show that the difference between the total number of chromosome breakages in the individuals living in the high background radiation area and that in the control area (0.32x10/sup -2/ and 0.27x10/sup -2/ per cell respectively) is not significant whereas that between the numbers of two-hite aberrations (mainly dicentric) in the same two groups (0.042x10/sup -2/ and 0.0048x10/sup -2/ per cell) is significant (X/sup 2/ = 6.1475, P<0.05). In addition, the normal value of the chromosome aberrations of human lymphocytes was analyzed.

  13. Growth retardation of paramecium and mouse cells by shielding them from background radiation

    International Nuclear Information System (INIS)

    In the 1970s and 1980s, Planel et al. reported that the growth of paramecia was decreased by shielding them from background radiation. In the 1990s, Takizawa et al. found that mouse cells displayed a decreased growth rate under shielded conditions. The purpose of the present study was to confirm that growth is impaired in organisms that have been shielded from background radiation. Radioprotection was produced with a shielding chamber surrounded by a 15 cm thick iron wall and a 10 cm thick paraffin wall that reduced the γ ray and neutron levels in the chamber to 2% and 25% of the background levels, respectively. Although the growth of Paramecium tetraurelia was not impaired by short-term radioprotection (around 10 days), which disagreed with the findings of Planel et al., decreased growth was observed after long-term (40-50 days) radiation shielding. When mouse lymphoma L5178Y cells were incubated inside or outside of the shielding chamber for 7 days, the number of cells present on the 6th and 7th days under the shielding conditions was significantly lower than that present under the non-shielding conditions. These inhibitory effects on cell growth were abrogated by the addition of a 137Cs γ-ray source disk to the chamber. Furthermore, no growth retardation was observed in XRCC4-deficient mouse M10 cells, which display impaired DNA double strand break repair. (author)

  14. Radiation Backgrounds at Cosmic Dawn: X-Rays from Compact Binaries

    CERN Document Server

    Madau, Piero

    2016-01-01

    We compute the expected X-ray diffuse background and radiative feedback on the intergalactic medium (IGM) from X-ray binaries prior and during the epoch of reionization. The cosmic evolution of compact binaries is followed using a population synthesis technique that treats separately neutron stars and black hole binaries in different spectral states and is calibrated to reproduce the observed X-ray properties of galaxies at z6. Radiative transfer effects modulate the background spectrum, which shows a characteristic peak between 1 and 2 keV. While the filtering of X-ray radiation through the IGM slightly increases the mean excess energy per photoionization, it also weakens the radiation intensity below 1 keV, lowering the mean photoionization and heating rates. Numerical integration of the rate and energy equations shows that the contribution of X-ray binaries to the ionization of the bulk IGM is negligible, with the electron fraction never exceeding 1%. Direct HeI photoionizations are the main source of IGM ...

  15. Preliminary study on the measurement of background radiation dose at Antarctica during 32nd expedition

    International Nuclear Information System (INIS)

    A significant proportion (10%) of the natural background radiation is of cosmic origin. Cosmic ray consists of gamma, protons, electrons, pions, muons, neutrons and low Z nuclei. Due to the geomagnetic effect, cosmic radiation levels at poles are higher. As a consequence, personnel working in Antarctica (or Arctic) are subjected to high level of cosmic radiation. The present study gives the details of the estimation of background radiation (neutrons, gamma and electrons) dose rate around the Indian station at Antarctica named 'Bharati' measured during 32nd Indian scientific expedition to Antarctica (32nd INSEA). The measurement was carried out by passive dosimeters such as TLDs and CR-39 and active dosimeter such as RadEye G portable gamma survey meter. Gamma and electron components were measured using TLDs and survey meter, whereas CR-39 SSNTDs and neutron sensitive TLDs were used for neutron measurements. These detectors were deployed at few selected locations around Bharati station for about 2½ months during summer expedition. The neutron detectors used in the study were pre-calibrated with 241Am-Be fast/thermal neutron source. The fast neutron dose rate measured based on CR-39 detector was found to about 140-420 nSv/h. The gamma dose rate evaluated by TLDs/survey meter are in the range of 290-400 nSv/h. (author)

  16. A survey of senile dementia in the high background radiation areas in Yangjiang, China

    International Nuclear Information System (INIS)

    Objective: To evaluate the effects of long-term low dose and low dose-rate ionizing radiation exposure on the prevalence rate of senile dementia, further assess the effects of low-dose radiation exposure on central nervous system and study the pathogen of senile dementia, and provide direct observational data of human beings. Methods: A cross-sectional study of the prevalence of senile dementia was carried out in high background radiation areas in Yangjiang, Guangdong Province, China. The survey was conducted in two stages. For the initial screening, Hasegawa Dementia Scale (HDS) was used for all subjects. In the second stage, the stage of diagnosis, special questionnaires of healthy state of old people were sued. The final diagnoses were made according to the third revised edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM III-R) of American Psychiatric Association. Results: 1018 inhabitants aged 65 years and over, including 513 persons in HBRA and 505 in CA were observed. According to DSM III-R, 61 cases (31 cases in HBRA and 30 cases in CA) of senile dementia were diagnosed. The prevalence rates of senile dementia are 6.04% in HBRA and 5.94% in CA, the total prevalence rate being 5.99%. Conclusion: No significant statistical difference in the prevalence rate of senile dementia between the two areas was found, suggesting that the prevalence rate of senile dementia in these areas is not associated with the high background radiation exposure

  17. Telomere length in human adults and high level natural background radiation.

    Directory of Open Access Journals (Sweden)

    Birajalaxmi Das

    Full Text Available BACKGROUND: Telomere length is considered as a biomarker of aging, stress, cancer. It has been associated with many chronic diseases such as hypertension and diabetes. Although, telomere shortening due to ionizing radiation has been reported in vitro, no in vivo data is available on natural background radiation and its effect on telomere length. METHODOLOGY/PRINCIPAL FINDINGS: The present investigation is an attempt to determine the telomere length among human adults residing in high level natural radiation areas (HLNRA and the adjacent normal level radiation areas (NLNRA of Kerala coast in Southwest India. Genomic DNA was isolated from the peripheral blood mononuclear cells of 310 individuals (HLNRA: N = 233 and NLNRA: N = 77. Telomere length was determined using real time q-PCR. Both telomere (T and single copy gene (S specific primers were used to calculate the relative T/S and expressed as the relative telomere length. The telomere length was determined to be 1.22+/-0.15, 1.12+/-0.15, 1.08+/-0.08, 1.12+/-0.11, respectively, among the four dose groups (5.00 mGy per year, which did not show any dose response. The results suggested that the high level natural chronic radiation did not have significant effect on telomere length among young adult population living in HLNRA, which is indicative of better repair of telomeric ends. No significant difference in telomere length was observed between male and female individuals. In the present investigation, although the determination of telomere length was studied among the adults with an age group between 18 to 40 years (mean maternal age: 26.10+/-4.49, a negative correlation was observed with respect to age. However, inter-individual variation was (0.81-1.68 was clearly observed. CONCLUSIONS/SIGNIFICANCE: In this preliminary investigation, we conclude that elevated level of natural background radiation has no significant effect on telomere length among the adult population residing in HLNRAs of

  18. Statistical analyses of cancer mortality data of high background radiation areas of Yangjiang

    International Nuclear Information System (INIS)

    The author describes the methodology and results of the recent statistical analysis of cancer mortality data between 1970-1986 of high background radiation areas in Yangjiang, Guangdong, China. This analysis emphases on the establishment of reasonable mathematical models, parameter estimation techniques and combined analysis of data collected in different survey periods. Dose-response analyses were carried out in more detail to detect radiation effects. Statistical estimation of the upper confidence bounds of hazardous effect of radiation is given in terms of the upper confidence limit of excess relative risk of all cancers and of leukemia. The analysis further confirms that there is no correlation between radiation exposure and mortality from all cancers or from leukemia. Estimates of radiation induced cancer risk were made based on three mathematical models. Each model was designed for a specific subset of data which were collected differently in method or contain different information. The upper confidence limit of the excess relative risk was also estimated using the likelihood method. It is noted that the estimate of the upper bound of cancer risk is consistent with or similar to the result of occupational exposure and the risk extrapolated from the Japanese A-bomb study. Therefore, these results strengthen the conclusion that the estimates obtained through extrapolation from high dose data do not seriously underestimate the risk of low-dose exposure, but leave open the possibility that extrapolation may overestimate risks

  19. Epidemiological studies on disturbances of human fetal development in areas with various doses of natural background radiation. I. Relationship between incidences of Down's syndrome or visible malformation and gonad dose equivalent rate of natural background radiation

    International Nuclear Information System (INIS)

    The relationship between environmental radiation to the gonads and incidences of Down's syndrome and visible malformation was analyzed using Kendall's rank correlation method. The subjects, studied during a 3-yr period (1979-1981), were inhabitants of 46 prefectures in Japan that had various dose rates of natural background ionizing radiation. Results showed that the natural background very low-dose radiation rate was not a predominant factor responsible for inducing Down's syndrome or other visible malformations

  20. Confounding factors in radiation epidemiology and their comparability between high background radiation areas and control areas in Yangjiang, China

    International Nuclear Information System (INIS)

    Objective: Confounding factors in radiation epidemiology and their comparability among the four different dose-rate groups in high background radiation areas were studied. Methods: The demography data were collected by a specific registration method. For the components of diet and life style, the samples were taken by a stratified random sampling method. Results: The sex-, age-distributions and the life expectancy of the members of a cohort 35 years old and above in the four dose-rate groups were similar to each other. The components of diet were constituted mostly of grains and vegetables with less meat, eggs and milk. The percentages of cigarette smokers were 27.7%-31.3% in both male and female subjects and the percentages of alcohol drinkers were 4.0%-6.9% in them. Conclusion: The results show that there is good comparability between the four dose-rate groups except for background radiation level, and it is suggested that the taken food consisting of grains and vegetables may be a beneficial factor leading to low incidence of malignancies in this area

  1. Research And Investigation To Establish The Database Of Environment Radiation Background For Vietnam (Phase 2009 -2011)

    International Nuclear Information System (INIS)

    Setting up data base of natural radiation background serves for planning socio-economics development in a province as well as the whole country and estimating annual effective dose of population. Beside external irradiation dose caused by the natural radioisotopes in the series 238U, 232Th and 40K in soil, population has been received internal dose caused by the above radioisotopes taken in the body from several ways. In order to complete the database of national radiation background and go to estimate annual effective radiation dose of population in the whole country, this project focus to carry out the works as following: (i) Setting up database of radiation background in the whole country: 150 soil samples that collected in the districts of 46 provinces have been analyzed. The average activity concentration of 238U, 232Th and 40K are 37.86 Bq/kg, 58.88 Bq/kg and 462.78 Bq/kg, respectively. The outdoor, indoor and total annual effective doses are calculated: 0.087±0.036 mSv; 0.488±0.202 mSv and 0.576± 0.240 mSv, respectively. (ii) Setting up database of radiation background of province Ninh Thuan and Quang Nam: The detailed database of radiation background of all villages in Ninh Thuan and Quang Nam has been established. 84 soil samples in Ninh Thuan and 311 in Quang Nam were collected for analyze. The indoor and outdoor radon concentration at sampling positions has been measured. The average activities of 238U, 232Th, 40K, and 222Rn isotopes in Ninh Thuan are reported: 33.50 Bq/kg, 55.43 Bq/kg, 701.12 Bq/kg and 12.1 Bq/m3, 9.5 Bq/m3, respectively. The outdoor, indoor and total annual effective doses in Ninh Thuan are calculated: 0.095±0.029 mSv; 0.529±0.162 mSv and 0.624± 0.382 mSv, respectively. The average activities of 238U, 232Th, 40K, and 222Rn isotopes in Quang Nam are reported: 44.47 Bq/kg, 52.68 Bq/kg, 459.33 Bq/kg, 18.0 Bq/m3. The outdoor, indoor and total annual effective doses are calculated: 0.086±0.039 mSv; 0.482±0.216 mSv and 0.568± 0

  2. Hard gamma-radiation from the Galaxy central part and the diffusive background radiation based on ''Kosmos-561'' satellite data

    International Nuclear Information System (INIS)

    Gamma radiation from the Galaxy central region was researched. The experimental data were obtained during 1973 by means of the gamma telescope with acoustic spark chambers, installed aboard the ''Cosmos-561'' satellite. The flow of gamma quanta at E >= 100 MeV was determined in the band along the galactic equator equal to (1.77+-0.74)x10-4cm-2xs-1 rad-1. The gamma radiation spectrum of the Galaxy central region in the 100-700 MeV energy range was measured for the first time. The integral exponential spectrum index turned out to be 1.52+-0.49. The upper limit of the diffusion background was assessed as (7.1+-3.5)x10-5 cm-2xs-1xsr-1

  3. Epidemiological investigation of radiological effects in high background radiation areas of Yangjiang, China

    International Nuclear Information System (INIS)

    The purpose of this investigation is to provide some information for providing whether any detrimental effects exist in a large population whose families have been continuously exposed to a low dose rate radiation. Two areas in Yangjiang Country, characterized by high background radiation (HBR) with environmental gamma exposure, large population size and long-term inhabitants, were selected for evaluation of late effects of HBR. The areas with normal radiation background close to the Yangjiang Country were selected as control areas. Up to 1986 approximately one million person-years in each area in both HBR and control areas have been observed. No increase of cancer mortality was found in the HBR areas; on the contrary, cancer mortality tended to be lower in the HBR areas than the control areas. The prevalence of hereditary diseases and congenital defects was similar in both HBR and control areas, but the frequency of Down's syndrome was higher in the HBR areas (through within the normal range) than the control areas. A possible explanation is the difference of age of maternity between the HBR and control areas, and the extremely low frequency in the control areas. Possible factors influencing the incidence of mutationbased diseases were comparable in the HBR and control groups. However, the cultural and educational levels were somewhat different, probably affecting health status and family planning. It is likely that there may be a dose threshold for cancer incidence, but this remains to be determined by further research. (N.K.)

  4. Levels of thoron and progeny in high background radiation area of southeastern coast of Odisha (India))

    International Nuclear Information System (INIS)

    Exposure to radon, 222Rn, is assumed to be the most significant source of natural radiation to human beings in most cases. It is thought that radon and its progeny are major factors that cause cancer. The presence of thoron, 220Rn, was often neglected because it was considered that the quantity of thoron in the environment is less than that of radon. However, recent studies have shown that a high thoron concentration was found in some regions and the exposure to 220Rn and its progeny can equal or several time exceed that of 220Rn and its progeny. The results of thoron and its progeny measurements in the houses of high background radiation area (HBRA) of the southeastern coast of Odisha (India)) presented here. This area is one of the high background radiation areas in India with a large deposit of monazite sand which is the probable source of thoron. Both active and passive methods were employed for the measurement of thoron and its progeny in cement, brick and mud houses in the study area. Thoron concentration was measured using RAD-7 and Raduet. A CR-39 track detector was employed for the measurement of environmental thoron progeny, both in active and passive modes. Thoron and its progeny concentrations were found to be comparatively high in the area. A comparison between the results obtained with various techniques is presented in this paper. (authors)

  5. Radionuclides and radiation indices of high background radiation area in Chavara-Neendakara placer deposits (Kerala, India).

    Science.gov (United States)

    Derin, Mary Thomas; Vijayagopal, Perumal; Venkatraman, Balasubramaniam; Chaubey, Ramesh Chandra; Gopinathan, Anilkumar

    2012-01-01

    The present paper describes a detailed study on the distribution of radionuclides along Chavara - Neendakara placer deposit, a high background radiation area (HBRA) along the Southwest coast of India (Kerala). Judged from our studies using HPGe gamma spectrometric detector, it becomes evident that Uranium ((238)U), Thorium ((232)Th) and Potassium ((40)K) are the major sources for radioactivity prevailing in the area. Our statistical analyses reveal the existence of a high positive correlation between (238)U and (232)Th, implicating that the levels of these elements are interdependent. Our SEM-EDAX analyses reveal that titanium (Ti) and zircon (Zr) are the major trace elements in the sand samples, followed by aluminum, copper, iron, ruthenium, magnesium, calcium, sulphur and lead. This is first of its kind report on the radiation hazard indices on this placer deposit. The average absorbed dose rates (9795 nGy h(-1)) computed from the present study is comparable with the top-ranking HBRAs in the world, thus offering the Chavara-Neendakara placer the second position, after Brazil; pertinently, this value is much higher than the World average. The perceptibly high absorbed gamma dose rates, entrained with the high annual external effective dose rates (AEED) and average annual gonadal dose equivalent (AGDE) values existing in this HBRA, encourage us to suggest for a candid assessment of the impact of the background radiation, if any, on the organisms that inhabit along this placer deposit. Future research could effectively address the issue of the possible impact of natural radiation on the biota inhabiting this HBRA. PMID:23185629

  6. Radionuclides and radiation indices of high background radiation area in Chavara-Neendakara placer deposits (Kerala, India.

    Directory of Open Access Journals (Sweden)

    Mary Thomas Derin

    Full Text Available The present paper describes a detailed study on the distribution of radionuclides along Chavara - Neendakara placer deposit, a high background radiation area (HBRA along the Southwest coast of India (Kerala. Judged from our studies using HPGe gamma spectrometric detector, it becomes evident that Uranium ((238U, Thorium ((232Th and Potassium ((40K are the major sources for radioactivity prevailing in the area. Our statistical analyses reveal the existence of a high positive correlation between (238U and (232Th, implicating that the levels of these elements are interdependent. Our SEM-EDAX analyses reveal that titanium (Ti and zircon (Zr are the major trace elements in the sand samples, followed by aluminum, copper, iron, ruthenium, magnesium, calcium, sulphur and lead. This is first of its kind report on the radiation hazard indices on this placer deposit. The average absorbed dose rates (9795 nGy h(-1 computed from the present study is comparable with the top-ranking HBRAs in the world, thus offering the Chavara-Neendakara placer the second position, after Brazil; pertinently, this value is much higher than the World average. The perceptibly high absorbed gamma dose rates, entrained with the high annual external effective dose rates (AEED and average annual gonadal dose equivalent (AGDE values existing in this HBRA, encourage us to suggest for a candid assessment of the impact of the background radiation, if any, on the organisms that inhabit along this placer deposit. Future research could effectively address the issue of the possible impact of natural radiation on the biota inhabiting this HBRA.

  7. Natural background radiation induces cytogenetic radioadaptive response more effectively than occupational exposure in human peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Ramsar, a city in the north part of Iran, has the highest level of natural background radiation in the world. We compared induction of cytogenetic radioadaptive response by High Natural Background Radiation (HNBR) in Ramsar and X-Ray occupational exposure as inducing doses in human peripheral blood lymphocytes. 30 healthy control individuals, living in Ramsar but in ordinary background radiation areas (inducing dose = 0), 15 healthy individuals from Talesh Mahalleh, a region with extraordinary level of background radiation (max. inducing dose = 260 mGy/year) and 7 X-Ray radiographers working in Ramsar hospital located in normal natural background of ionising radiation (max. inducing dose = 20 mGy/year) were evaluated. Peripheral blood samples were prepared and exposed to challenge dose of 0 and 2 Gy. Lymphocytes were scored using analysis of metaphase, for the presence of chromosomal aberrations (simple deletion, dicentrics and rings). An adaptive response was observed in HNBR and radiation workers groups in comparison with sham controls. Also, compared with occupationally exposed group a significant marked increase in adaptive response was observed in HNBR group. These findings indicate that both natural background radiation and occupational exposure could induce cytogenetic radioadaptive response and it is more significant regarding to natural background ionising radiation. (author)

  8. Pre-operational background radiation monitoring of Emergency Planning Zone (EPZ) of Kudankulam Nuclear Power Plant using mobile radiation monitoring methodology

    International Nuclear Information System (INIS)

    A pre-operational background radiation monitoring was carried out in the Emergency Planning Zone (EPZ) of Kudankulam Nuclear Power Plant (KKNPP). The objective of the radiation survey at pre operational stage was to form baseline radiation data against which future changes in the environmental radiation due to the operation of KKNPP can be compared. The radiation mapping was carried out using mobile monitoring technique - as a state of the art technique, where various radiation monitoring instruments installed on a mobile van were simultaneously used for qualitative and quantitative assessment (dose rate as well as radionuclide identification). During the radiation monitoring survey most of the accessible areas in EPZ have been covered. The radiation data such as dose rate, counts rate and radionuclide activity concentration in the soil were retrieved from various radiation monitors, processed and analyzed. The preoperational background radiation monitoring in EPZ of KKNPP showed the elevated radiation field, which is of the order of 30 times the national average background radiation field, in some regions like Kuthankuzhi, Lakshmipuram, Navvaladi etc. The detailed survey and analysis showed the excess presence of 232Th and 40K in elevated radiation field areas. This study would help to form baseline radiation data against which any future changes in the environmental radiation due to the operation of KKNPP can be evaluated

  9. Background radiation in the Sydney metropolitan area scientific reality and public perception

    International Nuclear Information System (INIS)

    Very little information if any, is available to the public about the ubiquitous nature of low-level background radiation -both from terrestrial and cosmic sources - in our highly urbanised or predominantly agrarnian societies. Public perception has naively accepted that the combustion of precious oxygen by air breathing engines is both natural and societally acceptable. Little thought has been given to the fact that on the one planet known to be able to sustain life based on oxygen, this is a recipe for disaster. On the other hand, since the evolution or creation of our universe, billions of tonnes of radioactive material within the crust of planet earth together with radiation from the thermonuclear powers station of the solar system, the sun, have sustained life, assisted in its evolution and, through photosynthesis and energy deposition, have ensured its propagation. In this on-going student project, employing wide-band, sensitive scintillation radiation detectors, careful statistical analysis and an understanding of the physics of radium-uranium decay chain and the production of radon gas and its daughter products, fluctuation in the radiation fields of large cities is clearly demonstrated. The work is usually carried out by the author and his final year thesis and students have great educational value for the public, civic authorities, school teachers, the media and political decision makers

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

    Science.gov (United States)

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

    2015-09-01

    A monitoring program in boundary areas of a country is an appropriate way to indicate the level of public exposure. In this research, gamma background radiation was measured using TL dosimeters at 12 boundary areas as well as in the capital city of Iran during the period 2010 to 2011. The measurements were carried out in semi-annual time intervals from January to June and July to December in each year. The maximum average dose equivalent value measured was approximately 70 μSv/month for Tehran city. Also, the average dose values obtained were less than 40 μSv/month for all the cities located at the sea level except that of high level natural radiation area of Ramsar, and more than 55 μSv/month for the higher elevation cities. The public exposure due to ambient gamma dose equivalent in Iran is within the levels reported by UNSCEAR. PMID:26057985

  11. B polarization of cosmic background radiation from second-order scattering sources

    International Nuclear Information System (INIS)

    B-mode polarization of the cosmic background radiation is induced from purely scalar primordial sources at second order in perturbations of the homogeneous, isotropic universe. We calculate the B-mode angular power spectrum ClBB sourced by the second-order scattering term in the full second-order Boltzmann equations for the polarized radiation phase-space density, which have recently become available. We find that at l ≈ 200 the second-order effect is comparable to the first-order effect for a tensor-to-scalar ratio of r = 10−6, and to about 2·10−4 at l ≈ 1000. It is always negligible relative to the weak-lensing induced contribution

  12. Measurements of External Gamma Radiation in the Area of Low Natural Background

    International Nuclear Information System (INIS)

    The automatic radiation monitoring in Slovenia incorporates measurements of external gamma radiation, aerosol radioactivity, radon progeny monitoring and radioactive deposition. At the moment, 44 gamma measuring probes are distributed uniformly over the territory of Slovenia, belonging to different institutions and integrated in a common network administered by the SNSA. External gamma radiation is measured by the system of probes with two GM tubes operating at different radiation ranges. The measuring stations used are mostly supplied by the Slovenian manufacturer AMES, type MFM-202 (in further text referred to as MFM), and partially by the Finish company RADOS Technology Oy, type ALNOR RD-02L (in further text referred to as ALNOR). These probes are normally installed within an undisturbed area (grassland), fixed at a standard height of 1 m above the ground and connected via radio or telephone to local data gathering stations. Within the scope of automatic monitoring, the data thus collected are also analyzed, used for alarming, archived and prepared for on-line presentation on the Internet. The difference between ALNOR and MFM probes is shown to be constant even in the condition of low natural background. If we take into account previous measurements which were made in order to check instrument calibrations, one can conclude that the difference is a linear shift that can be either added to the ALNOR results or subtracted from the MFM results. It is supposed to be due to inherent instrument radioactivity and electronic noise. One manufacturer (ALNOR) chose to subtract this instrument background from the measured results, the other one (MFM) did not. (author)

  13. Inhalation and external doses in coastal villages of high background radiation area in Kollam, India

    International Nuclear Information System (INIS)

    The observational evidence for radiation-induced health effects in humans comes largely from the exposures to high doses received over short periods of time. The rate of induction of any health risk at low doses and dose rates is estimated by extrapolation from observations at high doses. Effects of low dose/low dose rate could be done by the study of populations that have been exposed to slightly above-average natural radiation doses. Southwest coastal line of the Kerala state in India is one such region known to have elevated levels of background radioactivity mainly due to the mineral-rich sand available with high abundance of thorium. In the present work, a study was conducted to investigate the inhalation and external radiation doses to human beings in the high background radiation area along the southwest coast of Kerala. Five hundred dwellings were selected for the study. All the selected houses were at least 10 y old with similar construction. Long-term integrated indoor measurements of the external gamma dose using thermoluminescent dosemeters (TLDs) and the inhalation dose with the SSNTD-based twin-cup dosemeters were carried out in the dwellings simultaneously. Ambient gamma dose measurements were also made with a GM tube-based survey meter while deploying and retrieving the dosemeters. The data show a high degree of heterogeneity. The inhalation dose was found to vary from 0.1 to 3.53 mSv y-1 and the external dose rates had a range of 383-11419 μGy y-1. The external doses measured by the survey meter and TLDs showed an excellent correlation. (authors)

  14. Lower bound of optimization for the public considering dose distribution of radiation due to natural background radiation

    International Nuclear Information System (INIS)

    The International Commission on Radiological Protection (ICRP) released drafts of new recommendations in June 2004, June 2006 and January 2007 and finally approved a new set of fundamental recommendations on the protection of humans and the environment from ionizing radiation at its meeting in Essen, Germany, 19-21 March 2007. In the process of the completion of the draft recommendations, the numerical value for the minimum dose constraint ensuring public protection was deleted or redescribed using other expressions. This issue remains undetermined even in the recently released Publication 103. On the other hand, ICRP also recently published a new concept of a representative person in Publication 101. This representative person is a hypothetical person exposed to a dose that is representative of the most highly exposed persons in the population. On the basis of this new concept, it is theoretically reasonable that the 95th percentile of the dose received by such representative persons is always lower than the dose constraint, which indicates that the main part of the dose distribution is considerably lower than the dose constraint. In this study, by using the relationship between the dose constraint and the dose distribution of the representative persons and a probabilistic approach using Monte Carlo calculation techniques, the effects of the dose distribution of radiation due to manmade radioactive nuclides when added to those of natural background radiation have been carefully investigated. The results show that additional exposure to manmade radiation of up to 0.5 mSv/y (as a dose constraint) would not significantly change the distribution of the public dose. Taking into consideration such probabilistic analysis and the rationale behind the derivations of exemption and clearance levels, it can be concluded that the minimum dose constraint that requires optimization in radiation protection should be set to 0.1 mSv/y, which is one order of magnitude higher than 0

  15. Natural background radiation and 137Cs inventories in southern Nevada. Preliminary report on fallout, December 1980

    International Nuclear Information System (INIS)

    External radiation measurements and soil sampling were performed at 28 sites in southern Nevada as part of an extensive radiological survey to determine residual levels of fission products and transuranic nuclides in Utah and Nevada as a result of nuclear weapons tests at the Nevada Test Site (NTS) during 1951 to 1958. The natural background exposure rate was found to vary by about a factor of two. The 137Cs inventories tended to be lower than expected indicating the effects of wind erosion. Cobalt-60 and 241Am were detected at several sites which were reported to be hotspots in post-shot radiological surveys

  16. Cosmological perturbations of quantum mechanical origin and anisotropy of the microwave background radiation

    CERN Document Server

    Grishchuk, L P

    1994-01-01

    A theory of quantum-mechanical generation of cosmological perturbations is considered. The conclusion of this study is that if the large-angular-scale anisotropy in the cosmic microwave background radiation is caused by the long-wavelength cosmological perturbations of quantum mechanical origin, they are, most likely, gravitational waves, rather than density perturbations or rotational perturbations. Some disagreements with previous publications are clarified. This contribution to the Proceedings is based on Reference~[34]. NOTE: To generate an output, please extract and save the file crckapb.sty which appear at the beginning of the main file.

  17. Cosmic Microwave Background Radiation Constraints on a Modified Chaplygin Gas Model

    Institute of Scientific and Technical Information of China (English)

    LIU Dao-Jun; LI Xin-Zhou

    2005-01-01

    @@ A modified Chaplygin gas model of unifying dark energy and dark matter with the exotic equation of state p = Bρ- A/ρα , which can also explain the recent expansion of the universe, is investigated by means of constraining the location of the peak of the cosmic microwave background radiation spectrum. We find that the result of CMBR measurements does not exclude the nonzero value of parameter B, but allows it in the range -0.35 (<~) B (<~) 0.025.

  18. Biaxial lidar efficiency rising based on improving of spatial selectivity and stability against background radiation

    Energy Technology Data Exchange (ETDEWEB)

    Agishev, R.R.; Bajazitov, R.A.; Galeyev, M.M. [Kazan State Technical Univ., Tatarstan (Russian Federation). Dept. of Radioelectronic and Quantum Systems

    1996-12-31

    A criterion of spatial-angular efficiency (SAE) of remote electro-optical systems for atmosphere monitoring is formulated. The dependencies of the SAE from normalized range and minimal operating range for different optical receiving schemes of ground-based biaxial lidar are analyzed. It is shown that low SAE of traditional VIS and NIR systems are a main cause of a low signal-to-background-noise ratio at the photodetector input, the considerable measurements errors. and the following low accuracy of atmospheric optical parameters reconstruction. The most effective protection against sky background radiation in such systems consists in forming an angular field according to the introduced SAE criterion. Some approaches to achieve high value of the SAE-parameter for receiving system optimization are discussed.

  19. Integrated Molecular Analysis Indicates Undetectable Change in DNA Damage in Mice after Continuous Irradiation at ~ 400-fold Natural Background Radiation

    OpenAIRE

    Olipitz, Werner; Wiktor-Brown, Dominika; Shuga, Joe; Pang, Bo; McFaline, Jose; Lonkar, Pallavi; Thomas, Aline; Mutamba, James T; Greenberger, Joel S.; Samson, Leona D.; Dedon, Peter C; Yanch, Jacquelyn C.; Engelward, Bevin P.

    2012-01-01

    Background: In the event of a nuclear accident, people are exposed to elevated levels of continuous low dose-rate radiation. Nevertheless, most of the literature describes the biological effects of acute radiation. Objectives: DNA damage and mutations are well established for their carcinogenic effects. We assessed several key markers of DNA damage and DNA damage responses in mice exposed to low dose-rate radiation to reveal potential genotoxic effects associated with low dose-rate radiation....

  20. Estimation of collective effective dose due to natural background radiation in Egypt

    Science.gov (United States)

    Henaish, B. A.; Tawfik, A. A.; Abu Zaid, H.; Gomaa, M. A.

    1994-07-01

    During the last few years, worldwide attention has been directed towards the estimation of natural background radiation levels. Several environmental monitoring networks have been established for systematic data collection and exchange of information.In the present study, measurements of annual effective dose from terrestrial γ-rays are carried out at pre-selected sites within several Egyptian governorates by using a calibrated gas-filled GM-detector connected to a microcomputer system. Contribution of the secondary cosmic-rays, which is of prime importance at sea level, is achieved by carrying out computation based on theoretical considerations.Terrestrial effective dose in Egypt is found to be between 106 and 371 μSv/yr, meanwhile the computed cosmic rays contribution is 260-296 μSv/yr. Accordingly, the annual collective effective dose due to natural background radiation is about 27,253 Man Sv for the last Egyptian population count (1989) considering 0.8 and 0.2 indoor and outdoor occupancy factors.

  1. A method of reducing background radiance for emissivity-compensated radiation thermometry of silicon wafers.

    Science.gov (United States)

    Iuchi, T; Toyoda, Y; Seo, T

    2013-02-01

    We studied the spectral and directional emissivities of silicon wafers using an optical polarization technique. Based on simulation and experimental results, we developed two radiation thermometry methods for silicon wafers: one is based on the polarized emissivity-invariant condition and the other is based on the relationship between the ratio of the p- and s-polarized radiance and the polarized emissivity. These methods can be performed at temperatures above 600 °C and over a wide wavelength range (0.9-4.8 μm), irrespective of the dielectric film thickness and the substrate resistivity, which depends on the dopant concentration. The temperature measurements were estimated to have expanded uncertainties (k = 2) of less than 5 °C. With a view to practically applying these methods, we investigated a method to reduce the intense background radiance produced by high-intensity heating lamps. We found that the background radiance can be greatly reduced by using a radiometer that is sensitive to wavelengths of 4.5 or 4.8 μm and suitable geometrical arrangements of a quartz plate. This opens up the possibility of using the two proposed radiation thermometry methods in practical applications. PMID:23464239

  2. Quantitative study of unstable chromosome aberrations following life time exposure of high background radiation in China

    International Nuclear Information System (INIS)

    Objective: To obtain a quantitative data regarding high background radiation-induced human chromosome aberrations by using advanced techniques. Methods: Environmental exposure dose for each individual was carefully measured. The estimated life-time doses ranged 25.2-244.8 and 5.4-51.7 mGy for individuals from the high background radiation area (HBRA) and the control area, respectively. Peripheral blood specimens were taken from 28 family members of three different generations in both areas. Purified lymphocyte culture technique for chromosome preparation was adopted and a total number of 70000 metaphases were scored. Results: In the case of HBRA, the frequencies of Dic + Rc increased with age, but no age-dependency was observed in subjects from the control area. The mean aberration yields significantly in excess of control value were seen in two older age groups. The aberration frequencies increased in proportion to the cumulative dose of the individuals living in HBRA. The estimated rate of increase per mGy was 1.5 x 10-5 per cell. Conclusion: It seems that Dic can continuously accumulated over life-time chronic low dose exposure and can serve as a reliable biological indicator. When the dose reduces to about 50 mGy, however, it becomes difficult to use to current method for quantitative analysis

  3. A method of reducing background radiance for emissivity-compensated radiation thermometry of silicon wafers

    Science.gov (United States)

    Iuchi, T.; Toyoda, Y.; Seo, T.

    2013-02-01

    We studied the spectral and directional emissivities of silicon wafers using an optical polarization technique. Based on simulation and experimental results, we developed two radiation thermometry methods for silicon wafers: one is based on the polarized emissivity-invariant condition and the other is based on the relationship between the ratio of the p- and s-polarized radiance and the polarized emissivity. These methods can be performed at temperatures above 600 °C and over a wide wavelength range (0.9-4.8 μm), irrespective of the dielectric film thickness and the substrate resistivity, which depends on the dopant concentration. The temperature measurements were estimated to have expanded uncertainties (k = 2) of less than 5 °C. With a view to practically applying these methods, we investigated a method to reduce the intense background radiance produced by high-intensity heating lamps. We found that the background radiance can be greatly reduced by using a radiometer that is sensitive to wavelengths of 4.5 or 4.8 μm and suitable geometrical arrangements of a quartz plate. This opens up the possibility of using the two proposed radiation thermometry methods in practical applications.

  4. Study of technogenic radiation contaminated territories background and environmental plants sustainability

    International Nuclear Information System (INIS)

    Full text : A certain amount of radioactive elements are spread in the land, water and air in these regions. In the raw oil-polluted areas radioactive elements ae rich with various metal oxides and non-metal elements increasing the radiation background in the water and in the air. The radioactive elements in the composition of the air are spread as the last product of the fuel of the transport facilities. All other creatures plants respond against ecological environmental factors with the special adaptation. As in medicine it is used from roentgen rays to find out complications in the human body, in the field of biology and agriculture it is used from the isotopes of the radioactive elements in formation of seeds embryo and elements movement in individual tissues during metabolism or gathering. Soil climate conditions of the Absheron peninsula are known to researchers. Radioactive elements are radiation background forming elements in the water, soil and weather of Absheron peninsula. Radioactive elements existing in water, air and land influence more to the plants growing rapidly and plants with high photosynthesis process

  5. Derivation of reference concentration values in foods for Brazilian high background radiation areas

    International Nuclear Information System (INIS)

    Aiming the establishment of Brazilian high background radiation area baseline data, 226Ra, 228Ra, 210Pb, 232Th, 228Th and 238U concentrations in foodstuffs arose from Brazilian high natural radiation areas were gathered, generating a databank containing concentration of radionuclides in 548 samples, 1871 single concentration measurements. Radionuclide concentration values in food vary widely because of the soil heterogeneity. In most analyzed samples the highest concentrations were found for 228Ra, followed by 226Ra, 210Pb, 228Th, 238U and 232Th. Differences among radionuclide concentrations in potato and carrot, kale and other leafy vegetables as well as among chicken, beef and pork were observed, showing that the joining of food in categories aiming comparison among concentrations can be meaningless. The origin of the food seems not play important role concerning the radionuclide concentration in it, since it was not found significant differences among the radionuclide concentrations in samples of a same food from the different areas. Reference values for some foodstuffs could be derived and in general the values can exceed by orders of magnitude those derived for temperate clime normal background areas. (author)

  6. Background radiation in the Albuquerque, New Mexico, U.S.A., area

    International Nuclear Information System (INIS)

    Background radiation levels in the Albuquerque, New Mexico, area are elevated when compared to much of the US. Soil K, U, and Th are somewhat elevated compared to average values in this country and generate roughly 60 mrem per year to the average resident. Cosmic ray contribution, due to the mean elevation of 5,200 ft above sea level, is 80 mrem/yr-well over the average for the US. Thirty percent of the homes in Albuquerque contain indoor radon levels over the EPA action level of 4 pCi/l compared to 10-12% of homes for the entire US. Indoor radon contributes about 100-300 mrem/yr. Total contributions from other minor sources are under 10 mrem/yr. Thus total background radiation received by Albuquerque residents is about 330-530 mrem/yr, well in excess of the rest of the US. The spread in mrem values is due to variations in the contribution from indoor radon

  7. The Cosmic Microwave Background Radiation-A Unique Window on the Early Universe

    Science.gov (United States)

    Hinshaw, Gary

    2010-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of 11 00. Data from the first seven years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. WMAP, part of NASA's Explorers program, was launched on June 30, 2001. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at the Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; Oxford University; University of Chicago; Brown University; University of British Columbia; and University of California, Los Angeles.

  8. Contributions of gamma ray bursters and supernovae to the terrestrial background radiation field

    International Nuclear Information System (INIS)

    generating mass extinction on earth, they are likely to have increased terrestrial background radiation levels significantly on a relatively frequent evolutionary timescale. This, in turn, may have implications for the way in which modern organisms respond to radiation dose. (author)

  9. The Natural Background Gamma Radiation Exposure in the Metropolitan Area of the Valley of Mexico.

    Science.gov (United States)

    Jones, Mary Feild

    Measurements of the natural background radiation have been made at numerous places throughout the world. Very little work in this field has been done in developing countries. In Mexico the natural radiation to which the population is exposed has not been assessed. This dissertation represents a pioneer study in this environmental area. The radiation exposure which occupants within buildings receive as a result of naturally occurring radionuclides present in construction materials is the principal focus. Data were collected between August 1979 and November 1980. Continuous monitoring was done with TLDs placed on site for periods of 3 to 6 months. The instrumentation used for "real-time" measurements was a portable NaI (Tl) scintillation detector. In addition, radiometric measurements were performed on construction materials commonly used in Mexican homes. Based on TLD readings taken within 75 dwellings, the typical indoor exposure for a resident of the study area is 9.2 (mu)Rh('-1). The average reading of the 152 indoor scintillometer surveys was 9.5 (mu)Rh('-1), the outdoor reading 7.5 (mu)Rh('-1). Results of one-way and multi-way analyses of the exposure data to determine the effect due to building materials type, geologic subsoil, age of dwelling, and elevation are also presented. The results of 152 indoor scintillometer surveys are described.

  10. Genetic background modulates lncRNA-coordinated tissue response to low dose ionizing radiation

    International Nuclear Information System (INIS)

    Long noncoding RNAs (lncRNAs) are emerging as key regulators of diverse cell functions and processes. However, the relevance of lncRNAs in the cell and tissue response to ionizing radiation has not yet been characterized. Here we used microarray profiling to determine lncRNA and mRNA expression in mammary glands of BALB/c and SPRET/EiJ mice after low-dose ionizing radiation (LDIR) exposure. We found that unirradiated mammary tissues of these strains differed significantly in baseline expressions of 290 lncRNAs. LDIR exposure (10 cGy) induced a significant change in the expression of many lncRNAs. The vast majority of lncRNAs identified to be differentially expressed after LDIR in either BALB/c or SPRET/EiJ had a significantly correlated expression pattern with at least one LDIR responsive mRNA. Functional analysis revealed that the response to LDIR in BALB/c mice is highly dynamic with enrichment for genes involved in tissue injury, inflammatory responses, and mammary gland development at 2, 4, and 8 weeks after LDIR, respectively. Our study demonstrates that genetic background strongly influences the expression of lncRNAs and their response to radiation and that lncRNAs may coordinate the tissue response to LDIR exposure via regulation of coding mRNAs

  11. Radiative transfer in a clumpy universe; 2, the ultraviolet extragalactic background

    CERN Document Server

    Haardt, F; Haardt, Francesco; Madau, Piero

    1995-01-01

    We present a detailed calculation of the propagation of AGN-like ionizing radiation through the intergalactic space. We model the ionization state of absorbing clouds, and show that the universe will be more opaque above 4\\,Ryd than previously estimated. Singly ionized helium in \\Lya forest clouds and Lyman-limit systems is found to be very efficient in reprocessing soft X-ray, helium-ionizing photons into ultraviolet, hydrogen-ionizing ones. We demonstrate that a significant fraction of the absorbed primary photons (emitted, e.g., by quasar sources) will be reradiated by the photoionized gas through \\Lya line emission, two-photon continuum, and recombination continuum radiation. In the light of new data and recent studies, we also reassess the contribution of the QSOs observed in optical surveys to the UV extragalactic background, and find that the stochastic reprocessing of quasar Lyman continuum radiation by hydrogen and helium along the line of sight will significantly affect the amplitude spectral shape,...

  12. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    International Nuclear Information System (INIS)

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation

  13. Measured radiation and background levels during transmission of megawatt electron beams through millimeter apertures

    International Nuclear Information System (INIS)

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 mev electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 mev operation

  14. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    Energy Technology Data Exchange (ETDEWEB)

    Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2013-11-01

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

  15. Cancer risks with adjustment to smoking among residents in Yangjiang high-background radiation area, China

    International Nuclear Information System (INIS)

    Radiation dosimetry and health effects of residents in a high-background radiation area in Yangjiang, China have been extensively studied. Results obtained with the cohort follow-up study during the period 1979 through 1998 were reported by a series of papers published in international and domestic journals. The new analysis mainly added the new follow-up data for the period 1999 to 2002, and made cancer risk estimation with adjustment to individual tobacco/cigarette smoking. The cohort follow-up during the period 1999-2002 accumulated 300523 person-years, and ascertained 2267 deaths, among them, 239 died of cancers. The sex and age-adjusted RR of all cancers in the entire HBRA comparing with that in the control areas was 0.95 (95% CI,0.73-1.24). Current smoking rate in HBRA and the control area were 30.79% and 31.55%, respectively, the difference was statistically significant (P =0.0228). Smoking rate of males in HBRA were statistically lower than that in the control area, 56.43% vs 59.85%, P <0,001. Only 1.4 % of the females were current smoker in the cohort, no difference was found between the two areas. No difference was found for age to start the smoking, and the smoking amount based on the random selected sample survey. With adjustment to smoking, the RR of all cancer deaths was estimated to be 1.00 (95% CI, 0.87-1.15); ERR/Sv was -0.02, 95% CI: -0.58, 0.78. No cancer risk associated with the lifetime exposure to high background radiation in Yangjiang was found. The cancer risk was slightly elevated with the adjustment to smoking. (author)

  16. A measurement of the low frequency spectrum of the cosmic microwave background radiation

    International Nuclear Information System (INIS)

    As part of a larger effort to measure the spectrum of the Cosmic Background Radiation (CBR) at low frequencies, the intensity of the CBR has been measured at a frequency of 1.410 GHz. The measurement was made by comparing the power received from the sky with the power received from a specially designed cooled calibration target with known properties. Sources of radiation other than the CBR were then identified and subtracted to calculate the antenna temperature of the CBR at 1.410 GHz. The instrument used to measure the CBR was a total-power microwave radiometer with a 25 MHz bandwidth centered at 1.410 GHz. The radiometer had a noise temperature of 80 K, and sufficient data were taken that radiometer noise did not contribute significantly to the total measurement error. The sources of error were predominantly systematic in nature, and the largest error was due to uncertainty in the reflection characteristics of the cold-load calibrator. Identification and subtraction of signals from the Galaxy (0.7 K) and the Earth's atmosphere (0.8 K) were also significant parts of the data reduction and error analysis. The brightness temperature of the Cosmic Background Radiation at 1.410 GHz is 222. +- 0.55 Kelvin. The spectrum of the CBR, as determined by this measurement and other published results, is consistent with a blackbody spectrum of temperature 2.741 +- 0.016. Constraints on the amount by which the CBR spectrum deviates from Planck spectrum are used to place limits on energy releases early in the history of the universe. 55 refs., 25 figs., 8 tabs

  17. Unique signatures of natural background radiation on human Y chromosomes from Kerala, India.

    Directory of Open Access Journals (Sweden)

    Sanjay Premi

    Full Text Available BACKGROUND: The most frequently observed major consequences of ionizing radiation are chromosomal lesions and cancers, although the entire genome may be affected. Owing to its haploid status and absence of recombination, the human Y chromosome is an ideal candidate to be assessed for possible genetic alterations induced by ionizing radiation. We studied the human Y chromosome in 390 males from the South Indian state of Kerala, where the level of natural background radiation (NBR is ten-fold higher than the worldwide average, and that from 790 unexposed males as control. RESULTS: We observed random microdeletions in the Azoospermia factor (AZF a, b and c regions in >90%, and tandem duplication and copy number polymorphism (CNP of 11 different Y-linked genes in about 80% of males exposed to NBR. The autosomal homologues of Y-linked CDY genes largely remained unaffected. Multiple polymorphic copies of the Y-linked genes showing single Y-specific signals suggested their tandem duplication. Some exposed males showed unilocus duplication of DAZ genes resulting in six copies. Notably, in the AZFa region, approximately 25% of exposed males showed deletion of the DBY gene, whereas flanking genes USP9Y and UTY remained unaffected. All these alterations were detected in blood samples but not in the germline (sperm samples. CONCLUSIONS: Exposure to high levels of NBR correlated with several interstitial polymorphisms of the human Y chromosome. CNPs and enhanced transcription of the SRY gene after duplication are envisaged to compensate for the loss of Y chromosome in some cells. The aforesaid changes, confined to peripheral blood lymphocytes, suggest a possible innate mechanism protecting the germline DNA from the NBR. Genome analysis of a larger population focusing on greater numbers of genes may provide new insights into the mechanisms and risks of the resultant genetic damages. The present work demonstrates unique signatures of NBR on human Y chromosomes

  18. Development of voids in the thin-wall approximation. III. Radiation-filled voids in a nonflat background

    International Nuclear Information System (INIS)

    The evolution of spherical radiation-filled voids in a nonflat Robertson-Walker background is studied within the context of the general relativistic thin-wall approximation. This work extends previous work on vacuum voids and flat radiation-filled voids. It is found that radiation-filled voids expand more readily than vacuum voids. Specific results indicate that voids surrounded by dust shells become comoving in an open (k = -1) universe. With the model used here, voids in a closed universe would contain blackbody radiation at a temperature significantly above the background. 13 references

  19. Background levels and radiation dose yield of o-tyrosine in chicken meat

    International Nuclear Information System (INIS)

    The measurement of o-tyrosine levels in poultry meat is a potential method for postirradiation dosimetry of poultry. The validity of using o-tyrosine for this purpose has not yet been established. As part of the validation process, the o-tyrosine content in unirradiated chicken meat, the radiation dose response curve, and the effects of postirradiation storage on o-tyrosine levels are examined. In 18 individual samples, the mean background level of o-tyrosine was 0.18 +/- 0.11 ppm (wet weight, 70% moisture), and the most frequent background level (60% of the cases) was between 0.05 and 0.15 ppm (wet weight, 70% moisture). In pooled samples of 10 chickens, the mean background level was 0.12 +/- 0.03 ppm (wet weight, 70% moisture). The levels were not significantly affected by storage at 5 degrees C (7 d) or by freezing the sample. The radiation dose response curve was linear within the dose range studied (0 to 10 kGy), with a slope of 0.127 + 0.003 ppm (wet weight)/kGy. Although there was some variation in the intercept (0.132 + 0.013), the slope was the same in all samples tested. Postirradiation storage at either 4 or 8 degrees C until spoilage did not affect the levels of o-tyrosine. These data indicate that o-tyrosine level may be useful for determining the absorbed dose in chicken meat gamma-irradiated to doses greater than 0.6 kGy. Further validation studies are continuing

  20. A New Upper Limit on the Polarization of the Cosmic Microwave Background Radiation

    CERN Document Server

    O'Dell, C

    2002-01-01

    The Cosmic Microwave Background Radiation (CMB) is an invaluable probe of the conditions of the early universe. Recent measurements of its spatial anisotropy have allowed accurate determinations of several fundamental cosmological parameters, such as the curvature of the universe, the shape of the spectrum of primordial density fluctuations, and the contribution of baryons, dark matter, and dark energy to the overall energy density of the universe. In addition to being spatially non-uniform, the CMB is theorized to be slightly polarized. Measurements of this polarization, particularly at large angular scales, have the potential to provide information on primordial gravitational waves, theories of inflation, and the ionization history of the universe, as well as help further constrain cosmological parameters. Polarization has not yet been detected in the CMB. This thesis describes a recent search for CMB polarization at large angular scales, conducted in the spring of 2000 at the University of Wisconsin-Madiso...

  1. Measurement of the intensity of the cosmic background radiation at 3.0 cm

    International Nuclear Information System (INIS)

    The intensity of the cosmic background radiation (CBR) has been measured at a wavelength of 3.0 cm as part of a program to measure th Rayleigh-Jeans spectrum of the CBR at five wavelengths between 0.33 cm and 12 cm. The instrument used is a dual-antenna Dicke-switched radiometer with a double-sideband noise temperature of 490 K and a sensitivity of 46 mK/Hz/sup 1/2/. The entire radiometer is mounted on bearings. The atmospheric emission was measured by rotating the radiometer, and thus directing one antenna to zenith angles of +- 300 and +- 400. 61 references, 24 figures, 18 tables

  2. Measurement of the large-scale anisotropy of the cosmic background radiation at 3mm

    International Nuclear Information System (INIS)

    A balloon-borne differential radiometer has measured the large-scale anisotropy of the cosmic background radiation (CBR) with high sensitivity. The antenna temperature dipole anistropy at 90 GHz (3 mm wavelength) is 2.82 +- 0.19 mK, corresponding to a thermodynamic anistropy of 3.48 +- mK for a 2.7 K blackbody CBR. The dipole direction, 11.3 +- 0.1 hours right ascension and -5.70 +- 1.80 declination, agrees well with measurements at other frequencies. Calibration error dominates magnitude uncertainty, with statistical errors on dipole terms being under 0.1 mK. No significant quadrupole power is found, placing a 90% confidence-level upper limit of 0.27 mK on the RMS thermodynamic quadrupolar anistropy. 22 figures, 17 tables

  3. Relation between cancer incidence or mortality and external natural background radiation in Japan

    International Nuclear Information System (INIS)

    Analysis was performed on the relationships between the organ dose-equivalent rate due to natural background radiation (mSv/a) and three parameters of cancer risk: the age-adjusted cancer incidence (patients x 105 persons x a-1) in 13 large areas, the standardized mortality ratio of cancers in 46 large areas, and the cancer mortality in the population aged more than 40 years old (cancer deaths x 105 persons x a-1) in 649 small areas. The age-adjusted liver cancer incidence in males fitted the exponential model significantly (p<0.01) and the relationship of stomach cancer mortality of aged males in small areas fitted the linear model significantly (p<0.05). No relationship was observed with regard to female cancer in either case. The relationships between the three parameters and various other cancers of both sexes were not statistically significant. (author)

  4. Thermodynamic analysis of a Schwarzschild black hole fed by cosmic microwave background radiation

    International Nuclear Information System (INIS)

    The analysis of black holes fed by the omnipresent Cosmic Microwave Background Radiation (CMBR) constitutes benchmark cases. The rate of energy and entropy variation of a Schwarzschild black hole fed by CMBR is analytically obtained. The entropy analysis revealed that there is a higher value of black hole's critical mass than that obtained from an energy analysis, which is needed for its existence with high probability. At this minimum value of mass of the Schwarzschild black hole, the entropy generated due to its existence becomes positive. The black hole's negentropy and the difference between its exit and inlet specific entropies are shown to more importantly correlate with its event horizon area than the black hole's entropy. (orig.)

  5. Thermodynamic analysis of a Schwarzschild black hole fed by cosmic microwave background radiation

    Science.gov (United States)

    Mahulikar, Shripad P.; Herwig, Heinz

    2013-01-01

    The analysis of black holes fed by the omnipresent Cosmic Microwave Background Radiation (CMBR) constitutes benchmark cases. The rate of energy and entropy variation of a Schwarzschild black hole fed by CMBR is analytically obtained. The entropy analysis revealed that there is a higher value of black hole's critical mass than that obtained from an energy analysis, which is needed for its existence with high probability. At this minimum value of mass of the Schwarzschild black hole, the entropy generated due to its existence becomes positive. The black hole's negentropy and the difference between its exit and inlet specific entropies are shown to more importantly correlate with its event horizon area than the black hole's entropy.

  6. Thermodynamic analysis of a Schwarzschild black hole fed by cosmic microwave background radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mahulikar, Shripad P. [Hamburg University of Technology, Institut fuer Thermofluiddynamik (M-21), Hamburg (Germany); Indian Institute of Technology Bombay, Department of Aerospace Engineering, P.O. IIT Powai, Mumbai (India); Herwig, Heinz [Hamburg University of Technology, Institut fuer Thermofluiddynamik (M-21), Hamburg (Germany)

    2013-01-15

    The analysis of black holes fed by the omnipresent Cosmic Microwave Background Radiation (CMBR) constitutes benchmark cases. The rate of energy and entropy variation of a Schwarzschild black hole fed by CMBR is analytically obtained. The entropy analysis revealed that there is a higher value of black hole's critical mass than that obtained from an energy analysis, which is needed for its existence with high probability. At this minimum value of mass of the Schwarzschild black hole, the entropy generated due to its existence becomes positive. The black hole's negentropy and the difference between its exit and inlet specific entropies are shown to more importantly correlate with its event horizon area than the black hole's entropy. (orig.)

  7. Radon-thoron exposures in high background radiation areas: a review

    International Nuclear Information System (INIS)

    The radon-thoron measurements reported in literature for the high background radiation areas (HBRAs) of the world are summarised here. The most important areas covered are the Radon Spas and the thorium bearing monazite deposits. Special mention is made of the ongoing programmes of radon-thoron survey in the monazite beach areas of India; preliminary measurements indicate significant levels of thoron exposures. The diurnal and seasonal variations are quite wide underscoring the importance of carrying out integrated measurements for meaningful assessments of population exposures. Radon-thoron inhalation dose rates upto 30 mSv/y have been measured in lran as well as India. It has been generally observed that the cumulative population doses due to radon-thoron inhalation are as high as those due to the external exposures in these HBRAs. (author). 7 refs., 2 tabs., 3 figs

  8. Dipole analysis on EGRET data of extragalactic gamma ray background radiation

    Science.gov (United States)

    Lin, Ying-Chi

    1990-01-01

    A dipole analysis on the EGRET (Energetic Gamma-Ray Experimental Telescope) data seems to be one of the numerous subjects that can be investigated for the extragalactic gamma ray background radiation. By the end of the first one and half years after launch, the all-sky survey program of GRO (Gamma Ray Observatory) will be completed. The EGRET detector will cover the full sky area fairly well by that time. A set of gamma ray data suitable for dipole moment calculations will be available. Furthermore, there now exist in the literature several dipole anisotropy results calculated for optical and infrared observations on the distribution of galaxies in the full sky. The results of dipole moment analysis from gamma ray observation can be compared with those at other wavebands, and hopefully some deeper understanding can be gained on the large scale structure of the Universe.

  9. Radiation induced mutants in elite genetic background for the augmentation of genetic diversity

    International Nuclear Information System (INIS)

    Rice (Oryza sativa L.), an important food crop for India, shows large genetic diversity. However, despite the large genetic resource, high genetic similarity is reported in cultivated varieties indicating genetic erosion. Radiation induced mutations provide genetic variability in elite background. In the present study, twenty gamma ray induced mutants of rice variety WL112 (carrying sd-1 semi-dwarfing gene) were analysed for genetic diversity using microsatellite markers. The high range of genetic diversity among mutants indicated that the mutants possess potential for enhancing variability in rice. Cluster analysis showed presence of five clusters having small sub-clusters. Earliness, semi-dwarf stature or resistance to blast disease observed among the mutants showed that these will be useful in breeding programmes. (author)

  10. Measurement of the large-scale anisotropy of the cosmic background radiation at 3mm

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, G.L.

    1983-12-01

    A balloon-borne differential radiometer has measured the large-scale anisotropy of the cosmic background radiation (CBR) with high sensitivity. The antenna temperature dipole anistropy at 90 GHz (3 mm wavelength) is 2.82 +- 0.19 mK, corresponding to a thermodynamic anistropy of 3.48 +- mK for a 2.7 K blackbody CBR. The dipole direction, 11.3 +- 0.1 hours right ascension and -5.7/sup 0/ +- 1.8/sup 0/ declination, agrees well with measurements at other frequencies. Calibration error dominates magnitude uncertainty, with statistical errors on dipole terms being under 0.1 mK. No significant quadrupole power is found, placing a 90% confidence-level upper limit of 0.27 mK on the RMS thermodynamic quadrupolar anistropy. 22 figures, 17 tables.

  11. Gravitational angular fluctuations of the cosmic background radiation produced by cosmological linear perturbations

    International Nuclear Information System (INIS)

    The gravitational angular fluctuations of light rays produced by linear density perturbations are investigated in the Einstein-de Sitter model. It is shown that, owing to the random-walk process aroused by the perturbations, the mean square of relative angular fluctuations of two neighbouring light rays increase as they propagate. If the density contrast is larger than 3 x 10-3 for the present size 30 Mpc, the angular fluctuations for the angle difference of several minutes are so large to play a role to decrease the small-scale anisotropy of the cosmic background radiation during the propagation from the decoupling epoch to the present. They may give us also a reason to the question why few quasars can be found for z > 4. (author)

  12. Measurement of anisotropy in the cosmic background radiation on a large angular scale at 33 GHz

    International Nuclear Information System (INIS)

    Results of a measurement of anisotropy in the 3 0K cosmic background radiation on a large-angular-scale are presented. Observations were carried out with a dual-antenna microwave radiometer operating at 33 GHz (0.89 cm wavelength) flown on board a U-2 aircraft to 20-km altitude. In eleven flights, between December 1976 and May 1978, the radiometer measured differential intensity between pairs of directions distributed over most of the northern celestial hemisphere with an rms sensitivity of +- 46m0K/√Hz. The measurements show clear evidence of anisotropy that is readily interpreted as due to the motion of the earth relative to the sources of the radiation; the anisotropy is well fit by a cosine distribution of amplitude 3.61 +- 0.54 millireverse arrowreverse arrow-degrees Kelvin (m0K), one part in 800 of 30K, implying a velocity of 361 +- 54 km/sec toward the direction 11.23 +- 0.46 hours right ascension, and 19.0 +- 7.50 declination. A simultaneous fit to a combined hypothesis of dipole (cos theta) and quadrupole (cos2 theta) angular distributions places a 1 m0K limit on the amplitude of most components of quadruple anisotropy with 90% confidence. Additional analysis places a 0.5 m 0K limit on uncorrelated fluctuations (sky-roughness) in the 30K background on an angular scale of the antenna beam width, about 70. This thesis describes the equipment development through three engineering flights and the data acquisition in eleven additional flights. The astrophysical results are then presented from the statistical analysis of the reduced data

  13. Calibration of low-frequency radio telescopes using the galactic background radiation

    Science.gov (United States)

    Dulk, G. A.; Erickson, W. C.; Manning, R.; Bougeret, J.-L.

    2001-01-01

    We consider the calibration of flux densities of radio bursts from decametric to kilometric wavelengths using ground-based and space-based data. The method we derive is applicable to low-frequency radio telescopes where galactic background radiation is the principal contribution to system temperature. It can be particularly useful for telescopes of low angular resolution observing spectra of radio bursts from the Sun and the planets because absolute calibration of these telescopes is very difficult with conventional techniques. Here we apply the method to observations from about 7 to 47 MHz that were made on the ground with the Bruny Island Radio Spectrometer located in Tasmania, Australia, and those from about 20 kHz to 13.8 MHz were made with the radio experiment WAVES on the WIND spacecraft. The spectrum of the galactic background radiation from 30 MHz has been carefully measured with low-resolution telescopes, starting more than a decade ago. We use this known spectrum to calibrate both BIRS and WAVES on an absolute scale. The accuracy we achieve is about a factor of two, whereas the flux densities of solar and planetary radio sources vary by many orders of magnitude. Our method permits inter-calibration of ground-based and space-based observations, and allows corrections to be made for instrumental uncertainties on both radio experiments. In addition, on the ground, it allows the spectra to be corrected for ionospheric absorption and partial ground reflections. As an application we show the spectrum of a solar type III burst observed from 47 MHz to 20 kHz. Its flux density was largest, S~ 10-17 W m-2 Hz-1, at about 3 MHz, while at 60 kHz and at 47 MHz it was lower by a factor of about 300.

  14. Observing the Cosmic Microwave Background Radiation: A Unique Window on the Early Universe

    Science.gov (United States)

    Hinshaw, Gary; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics,of the early universe. Within the framework of inflationary dark matter models observations of the anisotropy on sub-degree angular scales will reveal the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of approx. 1100. The validity of inflationary models will be tested and, if agreement is found, accurate values for most of the key cosmological parameters will result. If disagreement is found, we will need to rethink our basic ideas about the physics of the early universe. I will present an overview of the physical processes at work in forming the anisotropy and discuss what we have already learned from current observations. I will conclude with a brief overview of the recently launched Microwave Anisotropy Probe (MAP) mission which will observe the anisotropy over the full sky with 0.21 degree angular resolution. At the time of this meeting, MAP will have just arrived at the L2 Lagrange point, marking the start of its observing campaign. The MAP hardware is being produced by Goddard in partnership with Princeton University.

  15. An Analysis of Recent Measurements of the Temperature of the Cosmic Microwave Background Radiation

    Science.gov (United States)

    Smoot, G.; Levin, S. M.; Witebsky, C.; De Amici, G.; Rephaeli, Y.

    1987-07-01

    This paper presents an analysis of the results of recent temperature measurements of the cosmic microwave background radiation (CMBR). The observations for wavelengths longer than 0.1 cum are well fit by a blackbody spectrum at 2.74{+ or -}0.0w K; however, including the new data of Matsumoto et al. (1987) the result is no longer consistent with a Planckian spectrum. The data are described by a Thomson-distortion parameter u=0.021{+ or -}0.002 and temperature 2.823{+ or -}0.010 K at the 68% confidence level. Fitting the low-frequency data to a Bose-Einstein spectral distortion yields a 95% confidence level upper limit of 1.4 x 10{sup -2} on the chemical potential mu{sub 0}. These limits on spectral distortions place restrictions on a number of potentially interesting sources of energy release to the CMBR, including the hot intergalactic medium proposed as the source of the X-ray background.

  16. State background-radiation levels: results of measurements taken during 1975-1979

    Energy Technology Data Exchange (ETDEWEB)

    Myrick, T.E.; Berven, B.A.; Haywood, F.F.

    1981-11-01

    Background radiation levels across the United States have been measured by the Off-Site Pollutant Measurements Group of the Health and Safety Research Division at Oak Ridge National Laboratory (ORNL). These measurements have been conducted as part of the ORNL program of radiological surveillance at inactive uranium mills and sites formerly utilized during Manhattan Engineer District and early Atomic Energy Commission projects. The measurements included determination of /sup 226/Ra, /sup 232/Th, and /sup 238/U concentrations in surface soil samples and measurement of external gamma-ray exposure rates at 1 m above the ground surface at the location of soil sampling. This information is being utilized for comparative purposes to determine the extent of contamination present at the survey sites and surrounding off-site areas. The sampling program to date has provided background information at 356 locations in 33 states. External gamma-ray exposure rates were found to range from less than 1 to 34 ..mu..R/h, with an US average of 8.5 ..mu..R/h. The nationwide average concentrations of /sup 226/Ra, /sup 232/Th, and /sup 238/U in surface soil were determined to be 1.1, 0.98, and 1.0 pCi/g, respectively.

  17. State background-radiation levels: results of measurements taken during 1975-1979

    International Nuclear Information System (INIS)

    Background radiation levels across the United States have been measured by the Off-Site Pollutant Measurements Group of the Health and Safety Research Division at Oak Ridge National Laboratory (ORNL). These measurements have been conducted as part of the ORNL program of radiological surveillance at inactive uranium mills and sites formerly utilized during Manhattan Engineer District and early Atomic Energy Commission projects. The measurements included determination of 226Ra, 232Th, and 238U concentrations in surface soil samples and measurement of external gamma-ray exposure rates at 1 m above the ground surface at the location of soil sampling. This information is being utilized for comparative purposes to determine the extent of contamination present at the survey sites and surrounding off-site areas. The sampling program to date has provided background information at 356 locations in 33 states. External gamma-ray exposure rates were found to range from less than 1 to 34 μR/h, with an US average of 8.5 μR/h. The nationwide average concentrations of 226Ra, 232Th, and 238U in surface soil were determined to be 1.1, 0.98, and 1.0 pCi/g, respectively

  18. LSO background radiation as a transmission source using time of flight

    International Nuclear Information System (INIS)

    LSO scintillators (Lu2Sio5:Ce) have a background radiation which originates from the isotope Lu-176 that is present in natural occurring lutetium. The decay that occurs in this isotope is a beta decay that is in coincidence with cascade gamma emissions with energies of 307,202 and 88 keV. The coincidental nature of the beta decay with the gamma emissions allow for separation of emission data originating from a positron annihilation event from transmission type data from the Lu-176 beta decay. By using the time of flight information, and information of the chord length between two LSO pixels in coincidence as a result of a beta emission and emitted gamma, a second time window can be set to observe transmission events simultaneously to emission events. Using the time when the PET scanner is not actively acquiring positron emission data, a continuous blank can be acquired and used to reconstruct a transmission image. With this blank and the measured transmission data, a transmission image can be reconstructed. This reconstructed transmission image can be used to perform emission data corrections such as attenuation correction and scatter corrections or starting images for algorithms that estimate emission and attenuation simultaneously. It is observed that the flux of the background activity is high enough to create useful transmission images with an acquisition time of 10 min. (paper)

  19. The enhancement of natural background radiation dose around uranium micro-particles

    International Nuclear Information System (INIS)

    Full text: The biological effects of ionising radiations are mainly produced by the interaction, either directly or indirectly, between secondary electrons and the genetic components of living cells. An interesting radiological situation arises in the case of the absorption of relatively low energy X-rays and gamma rays, of energies below about 250 keV, by particles of high atomic number since the probability of absorption of the photon energy is proportional to the third to fourth power of atomic number. In this situation, highly ionising short-range photoelectrons are produced, which will cause a dose enhancement in the immediate vicinity of the particles. After it was shown conclusively that hot radioactive particles (contamination from nuclear power plants and atomic bomb tests) (Charles et al, J. Radiol. Prot., 23: 5-28, 2003) and warm radioactive particles (depleted uranium) (Royal Society, The health hazards of depleted uranium munitions-Part 1, 2001) do not present as serious a radiological hazard as some have asserted, their attention then focussed on the dose enhancement that uranium particles in the body would produce upon exposure to naturally occurring background gamma radiation (Busby, Euro. J. Biol. Bioelectromag., 1: 82-93, 2005). It was claimed that this enhancement was a factor of 500 to 1000, and that it would then contribute a significant radiation dose, in addition to the dose received from the radioactivity of the depleted uranium. The aim of this project was to obtain an accurate estimate of the enhancement due to high atomic number heavy metal micro-particles using the Monte Carlo code EGSnrc. Uranium was selected for the micro-particles since it is the extreme case of a high atomic number heavy metal. A cylindrical body, 32 cm diameter and 60 cm long, made from ICRU four-element tissue, was exposed to isotropic natural background gamma radiation. The doses in the vicinity of micron-sized uranium particles were calculated at different

  20. Natural radioactivity and associated radiation characteristic of the new high background radiation area of lambwe east southern Kenya

    International Nuclear Information System (INIS)

    Rocks and soils from a number of areas underlined by carbonatite rocks in Kenya have been associated with high levels of natural background radioactivity. People in such high background radiation areas (HBRA), are exposed to abnormally high annual absorbed dose (that have health implications) than the global normal 1 mSvyr-1. In this paper, results of field background radiation measurements, activity concentrations of primordial radionuclides in (mainly carbonatite rock and soil) matrices, and estimated annual external effective dose rates are presented for South and North Ruri hills in Lambwe East location of Suba District, which lies roughly between latitudes 0°30'S and 1°00'S, bounded on the east by longitude 34°30'E and on the west by the shores of Lake Victoria 16 and Winnam Gulf. Altitudes in the region range from about 1000 m on the shores of Lake Victoria to above 1800 m on top of the Ruri hills. The main geological features are carbonatite formations. Twenty one samples were analyzed using high-purity germanium (HPGe) gamma-ray spectrometer. The activity concentrations ranged 14.18 - 6559.99 Bqkg-1 (average: 1396.85 Bqkg-1) for Th-232; 2.73 - 499.24 Bqkg-1 (average: 178.69 Bqkg-1) for U-238; and 56.67 - 1454.73 Bqkg-1 (average: 508.67 Bqkg-1) for K-40. The variability in Th distribution could be due to another contributing factor apart from carbonatite: Homa hills geothermal field fluids might be responsible for delivery of Th to surface rocks; some hot spots have travertine deposits. Measured absorbed dose rates in air outdoors range 700 - 6000.00 nGyh-1 (mean: 2325.84 nGy h-1); assuming 0.4 occupancy factor, these values correspond to individual annual effective dose rates of 1.717 - 14.717 mSvyr-1 (mean: 5.705 mSv yr-1). Measured absorbed dose rates are higher than calculated values since they include the contribution of cosmic rays. The natural radioactivity is fractionated with higher levels in the soils than carbonatite rocks

  1. Case-control study of cancer deaths in high background radiation areas of China

    International Nuclear Information System (INIS)

    This paper presents the results of a case-control study of deaths from liver, stomach and lung cancers in the high background radiation areas (HBRA) in Yangjiang County and neighboring control areas (CA). The purpose of this study was to explore the probable relationship between the cancer deaths and the environmental mutation-related factors in the two areas, so that the role of elevated natural radiation in cancer mortality could be properly ascertained. The studied numbers of cases of liver, stomach and lung cancers were 64, 28 and 17 in HBRA, and 75, 36 and 13 in CA, respectively. The proportion of the number of cases to that of the controls was 1:1 for liver cancer and 1:2 for cancers of stomach and lung. The factors studied included pesticide, smoking, alcohol consumption, medical X-ray exposure, diet, and the socioeconomic status, such as occupation, education, economic income, living space etc. The data for this study were collected through interviewing. The data collected were analysed by methods of matched and unmatched studies. The results expressed by odds ratio (OR) show that there is no significant between most factors studied and cancer deaths, although the associations of desths from stomach cancer with drinking water of nonwell source and of lung cancer with alcohol consumption in HBRA, and the associations of liver cancer deaths with occupations involving poisonous and noxious substances, pesticide and alcohol, and of lung cancer with pesticide and lower family income in CA can be found. This study has provided some clues for explaining the difference in cancer mortalities between HBRA and CA

  2. THE BACKGROUND RADIATION AND EXPOSURE LEVELS AT VARIOUS SOUTH AFRICAN WEST COAST MILITARY UNITS

    Directory of Open Access Journals (Sweden)

    Jacques Bezuidenhout

    2014-11-01

    Full Text Available The West Coast of South Africa between St Helena Bay to the north and Langebaan Lagoon to the south is characterised by numerous granite protrusions. These outcrops are elements of the underlying Cape Granite Suite, which forms the bedrock of a large part of the Western Cape. Granite contains high levels of natural radionuclides, which results in high levels of natural background radiation in the surrounding area. The impacts of these high levels of radiation exposure on military personal are of concern. There are four military units located in this part of the West Coast, namely SAS Saldanha, 4 Special Forces Regiment, Langebaan Road Air Force Base and the Military Academy. Different sites in and around these military units were selected and soil samples were taken. Laboratory gamma ray measurements were done to determine the levels of natural radioactive nuclides in the soil samples. The radioactive nuclide concentrations were interpolated and then mapped with the help of geographic information systems (also known as geospatial information systems or GIS software. An evaluation of the annual dose rate of military personnel at the units on the West Coast was made and found to range between 0,017 mSv/y and 0,163 mSv/y. These values were mapped and compared to the average global annual dose rate of 0,070 mSv/y. This article reports on an investigation of these results and the overall exposure levels of personnel from the various military units on the West Coast of South Africa.

  3. Measurements of radon and thoron concentrations in high radiation background area using pin-hole dosimeter

    International Nuclear Information System (INIS)

    In present investigation, newly designed twin cup pin-hole dosimeter with LR-115 track detector has been used for the integrated measurements of radon and thoron in the environmental air of a high background radiation area in coastal Orissa. The twin cup dosimeters were calibrated before installation in the field. The calibration experiment was made in an inter calibration exercise at NIRS, Chiba, Japan. The resulting calibration factors were used to obtain the values of radon and thoron in the study area. Radon and thoron concentrations in the houses of study area were found to vary from 24 Bq/m3 to 98 Bq/m3 and 46 Bq/m3 to 689 Bq/m3, respectively. The indoor and outdoor gamma dose rates in the study area vary from 0.124 μGy/h to 0.257 μGy/h and 0.109 μGy/h to 0.361 μGy/h, respectively. The annual effective dose due to the exposure to indoor radon and progeny was found to vary from 0.70 mSv to 2.84 mSv with an average value of 1.73 mSv. However, the annual effective dose due to the exposure to thoron and progeny was found to vary from 1.16 mSv to 17.36 mSv with an average value of 7.36 mSv. Thoron concentration and gamma dose rate were found relatively higher in the area. - Highlights: • Results of a newly designed twin cup pin-hole dosimeter are reported in this paper. • Radon and thoron were measured in high background radiation area of India. • Concentration of thoron and resulting effective dose were found higher in the area. • The indoor and outdoor gamma dose rates were also relatively higher in the area. • The resulting dose to the people living in the area was estimated

  4. Assessment of background gamma radiation and determination of excess lifetime cancer risk in Sabzevar City, Iran in 2014

    Directory of Open Access Journals (Sweden)

    Akbar Eslami

    2016-01-01

    Full Text Available Background: Background gamma radiation levels vary in different locations and depended on many factors such as radiation properties of soil, building materials as well as construction types which human lives on it. People are always exposed to ionizing radiation, which could badly influence their health. The aim of this study was to evaluate the background gamma-ray dose rate and the estimated annual effective dose equivalent and determination of excess lifetime cancer risk in Sabzevar City, Iran. Methods: The aim of this cross-sectional study was to determine the dose rate of background gamma radiation in outdoor an indoor areas, 26 stations were selected using the map of the Sabzevar City. The amount of gamma radiation was measured at 4 months (September to January in 2014 year. The dosimeter used in this study was a survey meter, that is designed for monitoring radiation of x, gamma and beta rays. Results: The obtained results show that there are significant differences between the indoor and outdoor exposures (P> 0.05. We did not observe significant differences between the time of sampling and sampling locations, (P<0.05. The minimum and maximum values of dose rate were found 66±20 nSvh-1 and 198±28 nSvh-1. The annual effective dose for Sabzevar residents was estimated to be 0.85 mSv and also the amount of excess lifetime cancer risk was estimated 3.39×10-3. Conclusion: According to the results, the excess lifetime cancer risk and the annual effective dose for the Sabzavar City residents due to the background gamma radiation was higher than the global average (0.5 mSv. The epidemiological studies have been proposed to evaluate the risk of chronic diseases associated with natural radiation exposure among residents.

  5. High-impedence NbSi TES sensors for studying the cosmic microwave background radiation

    CERN Document Server

    Nones, Claudia; Benoit, Alain; Bergé, Laurent; Bideau, Aurelien; Camus, Philippe; Dumoulin, Louis; Monfardini, Alessandro; Rigaut, Olivier

    2012-01-01

    Precise measurements of the cosmic microwave background (CMB) are crucial in cosmology, because any proposed model of the universe must account for the features of this radiation. Of all CMB measurements that the scientific community has not yet been able to perform, the CMB B-mode polarization is probably the most challenging from the instrumental point of view. The signature of primordial gravitational waves, which give rise to a B-type polarization, is one of the goals in cosmology today and amongst the first objectives in the field. For this purpose, high-performance low-temperature bolometric cameras, made of thousands of pixels, are currently being developed by many groups, which will improve the sensitivity to B-mode CMB polarization by one or two orders of magnitude compared to the Planck satellite HFI detectors. We present here a new bolometer structure that is able to increase the pixel sensitivities and to simplify the fabrication procedure. This innovative device replaces delicate membrane-based s...

  6. Nutrition status in residents in the high background radiation area of Yangjiang, China

    International Nuclear Information System (INIS)

    Objective: To investigate the current status of nutrition and examine the difference between inhabitants in the high background radiation area (HBRA) and the control area (CA). Methods: Sixty and sixty-five male farmers aged 50 and over were randomly selected from HBRA and CA, respectively. Information on dwelling history, history of disease, medical treatment and X-ray examination were collected by interview. Body height and weight were measured, and BMIs were calculated. Serum levels of total protein, albumin and globulin, triacylglycerol (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low- density lipoprotein cholesterol (LDL-C), Apo A1 and Apo B were measured. Results: There was difference in BMI distribution between the two groups. Averages of total biochemistry indexes measured were in normal range in the two groups. With adjustment to age distribution, the serum levels of total protein, albumin and triacylglycerol (TG) of residents in CA were higher than those in HBRA; high-density lipoprotein cholesterol level was higher in HBRA than that in CA. Conclusions: This serum assay of nutrients in HBRA and CA residents confirmed the results obtained from previous surveys. Both HBRA and CA residents have similar nutrition status, residents in CA consumed more animal protein and fat compared with those in HBRA. (authors)

  7. Level crossing analysis of cosmic microwave background radiation: a method for detecting cosmic strings

    International Nuclear Information System (INIS)

    In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known Kaiser-Stebbins phenomenon for exploring the signature of cosmic strings. We simulate a Gaussian map by using the best fit parameter given by WMAP-7 and then superimpose cosmic strings effects on it as an incoherent and active fluctuations. In order to investigate the capability of our method to detect the cosmic strings for the various values of tension, Gμ, a simulated pure Gaussian map is compared with that of including cosmic strings. Based on the level crossing analysis, the superimposed cosmic string with Gμ∼>4 × 10−9 in the simulated map without instrumental noise and the resolution R = 1' could be detected. In the presence of anticipated instrumental noise the lower bound increases just up to Gμ∼>5.8 × 10−9

  8. Study of thorium uptake by inhabitants of a high background radiation area

    International Nuclear Information System (INIS)

    Buena, located in the North of Rio de Janeiro, is characterized by its high natural radiation background, due to large deposits of monazite sand. The foodstuffs consumed by the population are basically composed of local products, which contain significant amounts of thorium. The analysis of complete cooked meals have shown an average daily intake of 18 mBq.d-1 of 232Th and 189 mBq.d-1 of 228Th. The average urine to feces ratio of 232Th from samples of volunteers was found equal to 7.5x10-2 . The comparison of the experimental data with the predicted urine to feces ratios derived using the biokinetic model for thorium described by the ICRP publication 69 and simulating inhalation and ingestion separately, lead to the conclusion that the thorium intake is a combination of inhalation and ingestion. The clearance rate of thorium of monazite in lungs has apparently behaved as Type M compound. Inhalation is the biggest contributor for the committed effective dose due to thorium internal exposure. (author)

  9. Arrows of time and chaotic properties of the cosmic background radiation

    International Nuclear Information System (INIS)

    We advance a new viewpoint on the connection between the thermodynamical and cosmological arrows of time, which can be traced via the properties of cosmic microwave background (CMB) radiation. We show that in the Friedmann-Robertson-Walker universe with negative curvature there is a necessary ingredient for the existence of the thermodynamical arrow of time. It is based on the dynamical instability of motion along null geodesics in a hyperbolic space. Together with special (de-correlated) initial conditions, this mechanism is sufficient for the thermodynamical arrow, whereas the special initial conditions alone are able to generate only a pre-arrow of time. Since the negatively curved space will expand forever, this provides a direct connection between the thermodynamical and cosmological arrows of time. The structural stability of the geodesic flows on hyperbolic spaces and hence the robustness of the proposed mechanism is especially stressed. We then point out that the main relations of equilibrium statistical thermodynamics (including the second law) do not necessarily depend on any arrow of time. Finally we formulate a curvature anthropic principle, which stipulates the negative curvature as a necessary condition for the time-asymmetric universe with an observer. CMB has to carry the signature of this principle as well. (author)

  10. Background radiation and individual dosimetry in the coastal area of Tamil Nadu (India)

    International Nuclear Information System (INIS)

    South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2x7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y-1. From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g-1 of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y-1 ranging from 2.79 to 14.17 mSv y-1. (authors)

  11. Concentrations of radionuclides in cassava growing in high background radiation area and their transfer

    International Nuclear Information System (INIS)

    The concentrations of several natural radionuclides in common cassava (Manihot esculenta Crantz) growing in Yangjiang County, a high background radiation area in Guangdong Province, and their uptake from soil and distribution in the plant were investigated. The results show that the concentrations of natural uranium and thorium in cassava root are of the order of 10-6 g/kg, and those of radium-226, radium-228, lead-210 and polonium-210 are of the order of 10-11 Ci/kg. The highest level is 9.30 +- 0.30 x 10-11 Ci/kg (lead-210), and the lowest is 3.99 +- 0.20 x 10-11 Ci/kg (radium-226). The levels of natural uranium, thorium, radium-226 and polonium-210 in cassava are below the limits stipulated by the regulations for food hygiene in China, while the lead-210 level approaches the limit. It is noticeable that the highest level of radium-228 is 7.28 +- 1.03 x 10-11 Ci/kg, 10.4 times higher than the limit. The transfer of all he nuclides from soil to different parts of cassava shows a pattern contrary to that of he nuclides in the other regions where uranium-and radium-containing waste water and phosphate fertilizer are used in agriculture

  12. Development of voids in the thin-wall approximation. II. Radiation-filled voids in a flat background

    International Nuclear Information System (INIS)

    The evolution of spherical radiation-filled voids in a spatially flat Robertson-Walker background is studied within the context of the general relativistic thin-wall approximation. This work extends previous discussions of vacuum voids. It is found that the inclusion of radiation within the void has significant quantitative and important qualitative effects on the evolution of the void. In particular, it is found that voids which do not collapse grow, at late times, like the particle horizon

  13. The evolution of the earth's background radiation field over the past four billion years

    International Nuclear Information System (INIS)

    Modern organisms may be more resistant to the adverse effects of radiation because mutation repair mechanisms evolved under higher radiation levels. This may help to shed some light on the current controversy regarding the biological effects of exposure to low levels of ionizing radiation. (author)

  14. Study of radiation background at the north crossing point of the BEPC Ⅱ in collision mode%Study of radiation background at the north crossing point of the BEPC Ⅱ in collision mode

    Institute of Scientific and Technical Information of China (English)

    莫晓虎; 秦庆; 屈化民; 王贻芳; 徐金强; 张天保; 张建勇; 张清江; Achasov Mikhail; 蔡啸; 傅成栋; Harris Fred; 刘倩; Muchnoi Nikolay

    2011-01-01

    Understanding the radiation background at the north crossing point (NCP) in the tunnel of BEPCII is crucial for the performance safety of the High Purity Germanium (HPGe) detector, and in turn of great significance for long-term stable running of the ener

  15. Radioecology teaching: evaluation of the background radiation levels from areas with high concentrations of radionuclides in soil

    International Nuclear Information System (INIS)

    The study of environmental radioactivity is a topic which is not usually included in physics courses in Brazilian and Latin American universities. Consequently, high-school teachers are not able to show experimentally or discuss with their students the effects of exposure to terrestrial radiation. This paper presents a laboratory experiment in a teaching programme on the physics of ionizing radiation. It is based on the evaluation of the background radiation levels from areas with high concentrations of natural or artificial radionuclides in the soil. A brief analysis of the theory behind the technique and a description of some measurements, including their interpretations, are presented

  16. Real-time airborne gamma-ray background estimation using NASVD with MLE and radiation transport for calibration

    Science.gov (United States)

    Kulisek, J. A.; Schweppe, J. E.; Stave, S. C.; Bernacki, B. E.; Jordan, D. V.; Stewart, T. N.; Seifert, C. E.; Kernan, W. J.

    2015-06-01

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this challenge, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements without the need for human analyst intervention. The method can be calibrated using radiation transport simulations along with data from previous flights over areas for which the isotopic composition need not be known. Over the examined measured and simulated data sets, the method generated accurate background estimates even in the presence of a strong, 60Co source. The potential to track large and abrupt changes in background spectral shape and magnitude was demonstrated. The method can be implemented fairly easily in most modern computing languages and environments.

  17. Real-time airborne gamma-ray background estimation using NASVD with MLE and radiation transport for calibration

    International Nuclear Information System (INIS)

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this challenge, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements without the need for human analyst intervention. The method can be calibrated using radiation transport simulations along with data from previous flights over areas for which the isotopic composition need not be known. Over the examined measured and simulated data sets, the method generated accurate background estimates even in the presence of a strong, 60Co source. The potential to track large and abrupt changes in background spectral shape and magnitude was demonstrated. The method can be implemented fairly easily in most modern computing languages and environments

  18. Radiative corrections to the background of μ → e γ decay

    International Nuclear Information System (INIS)

    Radiative muon decay in the kinematics similar to the neutrinoless decay μ → e γ is considered. Radiative corrections due to one-loop virtual photons and emission of additional soft or hard photons are taken into account. Analytical expressions and numerical estimations are presented

  19. Effect of background gas pressure and laser pulse intensity on laser induced plasma radiation of copper samples

    Science.gov (United States)

    Mehrabian, S.; Aghaei, M.; Tavassoli, S. H.

    2010-04-01

    Study of laser induced plasma emission of Cu in one dimension is numerically carried out. Effects of different background gas pressure (He), 100, 500, and 760 torr, and laser pulse intensities, 0.5, 0.7, and 1 GW/cm2, on the plasma emission as well as ablation processes are investigated. Under a specified condition, heat conduction equation in the target accompanied with gas dynamic equations in the plume is solved simultaneously. The mentioned equations are coupled to each other through the Knudsen layer conditions and the energy and mass balances at the interface between the target and the vapor. The Bremsstrahlung radiation of plasma and the spectral emission of copper atoms are studied under various background gas pressure and laser pulse intensities. Furthermore, number density of He, Cu, and the electron, pressure, and temperature of the plume under various conditions are obtained. In the early time after laser pulse, plasma radiation is mainly due to the Bremsstrahlung radiation while after some 10 ns, the plasma radiation is dominated by spectral emission of Cu atoms. A similar uncoupling is observed spatially. The Bremsstrahlung emission is dominant near the sample surface while at farther points the spectral emission is the dominant one. By increase in the background pressure and also the pulse intensity, the dominancy of the spectral emission would occur later in time and farther in position.

  20. Thorium intake due to consumption of locally grown vegetables by inhabitants of high radiation background areas by INAA

    International Nuclear Information System (INIS)

    Ingestion of radionuclides through food intake represents one of the important pathways for long term exposure. The concentration of radionuclides in the food stuff varies from place to place depending on the type of soil in which they are grown. In India, there are few locations where the radionuclide content is high. Some coastal towns of India namely, Chatrapur, Chavara, Manavalakurichi, Ullal etc are well known high natural radiation areas. The high background radiation is due to presence of monazite in the beach sands. Monazite contains thorium, uranium and rare earths. Radioactivity levels in local soil and the food grown in them are also higher than that in other areas

  1. Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

    International Nuclear Information System (INIS)

    A novel technique for the rejection of gamma background from charged-particle spectra was demonstrated using a CVD diamond detector with a 6Li neutron converter installed at a thermal neutron beamline of the TRIGA research reactor at the Atominstitut (Vienna University of Technology). Spectra of the alpha particles and tritons of 6Li(n,T)4He thermal neutron capture reaction were separated from the gamma background by a new algorithm based on pulse-shape analysis. The thermal neutron capture in 6Li is already used for neutron flux monitoring, but the ability to remove gamma background allows using a CVD diamond detector for thermal neutron counting. The pulse-shape analysis can equally be applied to all cases where the charged products of an interaction are absorbed in the diamond and to other background particles that fully traverse the detector

  2. Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

    Science.gov (United States)

    Kavrigin, P.; Finocchiaro, P.; Griesmayer, E.; Jericha, E.; Pappalardo, A.; Weiss, C.

    2015-09-01

    A novel technique for the rejection of gamma background from charged-particle spectra was demonstrated using a CVD diamond detector with a 6Li neutron converter installed at a thermal neutron beamline of the TRIGA research reactor at the Atominstitut (Vienna University of Technology). Spectra of the alpha particles and tritons of 6Li(n,T)4He thermal neutron capture reaction were separated from the gamma background by a new algorithm based on pulse-shape analysis. The thermal neutron capture in 6Li is already used for neutron flux monitoring, but the ability to remove gamma background allows using a CVD diamond detector for thermal neutron counting. The pulse-shape analysis can equally be applied to all cases where the charged products of an interaction are absorbed in the diamond and to other background particles that fully traverse the detector.

  3. Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kavrigin, P., E-mail: pavel.kavrigin@cividec.at [Vienna University of Technology (Austria); Finocchiaro, P., E-mail: finocchiaro@lns.infn.it [INFN Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Griesmayer, E., E-mail: erich.griesmayer@cividec.at [Vienna University of Technology (Austria); Jericha, E., E-mail: jericha@ati.ac.at [Vienna University of Technology (Austria); Pappalardo, A., E-mail: apappalardo@lns.infn.it [INFN Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Weiss, C., E-mail: Christina.Weiss@cern.ch [Vienna University of Technology (Austria); European Organisation for Nuclear Research (CERN), Geneva (Switzerland)

    2015-09-21

    A novel technique for the rejection of gamma background from charged-particle spectra was demonstrated using a CVD diamond detector with a {sup 6}Li neutron converter installed at a thermal neutron beamline of the TRIGA research reactor at the Atominstitut (Vienna University of Technology). Spectra of the alpha particles and tritons of {sup 6}Li(n,T){sup 4}He thermal neutron capture reaction were separated from the gamma background by a new algorithm based on pulse-shape analysis. The thermal neutron capture in {sup 6}Li is already used for neutron flux monitoring, but the ability to remove gamma background allows using a CVD diamond detector for thermal neutron counting. The pulse-shape analysis can equally be applied to all cases where the charged products of an interaction are absorbed in the diamond and to other background particles that fully traverse the detector.

  4. The fallacy of comparing diagnostic radiation with background radiation; and the need to learn from past mistakes

    Directory of Open Access Journals (Sweden)

    D J Emby

    2010-08-01

    Full Text Available The subject of radiation exposure for diagnostic purposes is currently a ‘hot’ topic, and it is appropriate that the debate around this issue is given exposure in the pages of the SAJR. I would like to comment on a few of the points raised by Dr Tipler in his article that appeared in the June 2010 SAJR.

  5. The X-ray log N-log S relation. [background radiation in extragalactic media

    Science.gov (United States)

    Boldt, Elihu

    1989-01-01

    Results from various surveys are reviewed as regards X-ray source counts at high galactic latitudes and the luminosity functions determined for extragalactic sources. Constraints on the associated log N-log S relation provided by the extragalactic X-ray background are emphasized in terms of its spatial fluctuations and spectrum as well as absolute flux level. The large number of sources required for this background suggests that there is not a sharp boundary in the redshift distribution of visible matter.

  6. Historical background and overview of epidemiological studies on the effects of low-level radiation

    International Nuclear Information System (INIS)

    Recognition of the carcinogenic effects of ionizing radiation dates from the early part of this century, when an increased frequency of skin cancer and leukemia was first reported in radiologists. In the interim, systematic epidemiological studies have disclosed additional carcinogenic effects in radiation workers, A-bomb survivors, patients exposed to diagnostic or therapeutic radiation, and other groups. The studies have provided sufficient data on dose-incidence relationships, the distribution of cancer in relation to age at irradiation and time after exposure, and organ-variations in susceptibility to enable attempts at quantitative assessment of the risks of low-level irradiation. Such assessments, although tentative and controversial, have exerted an important influence on developments in radiological protection

  7. Environmental gamma monitoring in high background radiation areas of Orissa using CaSO4:Dy TL dosimeters

    International Nuclear Information System (INIS)

    Naturally occurring radionuclides are the major contributor to the total effective dose of ionizing radiation received by the population. In India, there are quite a few monazite sand bearing placer deposits causing high background radiation along its long coastline. Chatrapur, Orissa is one of the high background areas of India. The beach sand of this area contains natural mineral Monazite abundantly. Maximum and minimum dose were found 1202. 1 μGy in spring and 483.8 μGy in monsoon at Port School and Gopalpur respectively. In spring, summer, monsoon and winter season the dose ranges were observed 1202.1-520.3, 1154.7-503.6, 1066.3-483.8 and 1141.7-508.5 μG respectively. (author)

  8. Effective doses of background radiation in the Almaty and the Kazakhstan nuclear sites areas

    International Nuclear Information System (INIS)

    The comparative results for determination of partial effective doses from each kind of ionizing radiation and all pathways of radionuclides intakes of Almaty city population, and localities adjoining to nuclear test sites (Lira and Azgir), as well as Semipalatinsk test site (STS). Results of effective dose calculations are evidencing about absence of considerable influence of tests on the sites on the natural radiation dose loads and about some exceeding of effective dose in Almaty above effective doses in the sites' areas. Artificial radionuclides contribution of the sites areas (beside STS) does not exceeds the level of global fallout in Almaty

  9. Social economical and psychological considerations in conveying potential radiation risks from high level natural background radiation to the residents of Ramsar, Iran

    International Nuclear Information System (INIS)

    X-rays and radioactivity were discovered more than 100 years ago but the need for protection against very low doses of ionizing radiation and especially different levels of natural radiation is still among the most controversial matters in radiobiology and radiation protection. According to formal reports, some areas in Ramsar, a city in northern Iran, are the inhabited areas with the highest levels of natural radiation studied so far. A population of about 2000 is exposed to average annual radiation levels of 10.2 mGy y''-1 and the highest recorded external gamma dose rates are about 130 mGy y''-1. We have previously shown that in high background radiation areas (HBRAs), cultured human lymphocytes of the inhabitants whose cumulative radiation doses were as much as 170 times more than those of a control area when subjected to 1.5 Gy challenge dose,were significantly more radioresistant compared to the residents of the control area (Mortazavi et al. 2002a,b, Mortazavi and Karam 2002, Ghiassi-Najed et al. 2002). The people who live in these areas are usually unaware of the high levels of natural radiation in their environment. Studies performed on the residents of these areas have indicated that the effective dose of the inhabitants, in some cases, is much higher than the dose limits for occupational irradiation. Considering recent policies of ICRP regarding suggesting dose limits for exposure to natural sources of ionizing including radon, it seems that the inhabitants should become familiar with the possible risks of the exposure to high levels of ionizing radiation. They should also realize that studies performed over the past years have indicated no detrimental effect. On the other hand, according to ICRP suggestions and considering the experiences in other countries, especially evacuation of the residents of contaminated areas after Chernobyl accident, setting any radiation protection regulation for the inhabitants without considering social, economic and

  10. The Cosmic Microwave Background Radiation Power Spectrum as a Random Bit Generator for Symmetric and Asymmetric-Key Cryptography

    CERN Document Server

    Lee, Jeffrey S

    2016-01-01

    In this note, the Cosmic Microwave Background (CMB) Radiation is shown to be capable of functioning as a Random Bit Generator, and constitutes an effectively infinite supply of truly random one-time pad values of arbitrary length. It is further argued that the CMB power spectrum potentially conforms to the FIPS 140-2 standard. Additionally, its applicability to the generation of a (n x n) random key matrix for a Vernam cipher is established.

  11. Radiation exposure map based on fuzzy logic for the representation of areas with high natural background

    International Nuclear Information System (INIS)

    The identification of areas with high concentrations of natural radionuclides is an important task in classifying these areas in relation to the health risk for residents in the region. The aim of this work is to identify areas of high exposure to nuclear radiation using a geographic representation based on the theory of fuzzy sets. Radiometric data obtained from previous works developed in a region of high concentrations in natural uranium were used to create a fuzzy map of the local radiation levels. During the image processing, a nonlinear filter was applied to eliminate noise i.e. to reduce isolated pixels that would eventually cause major uncertainties in the results. A resulting image was geographically positioned (WGS40) and obtained in gray scale. This image was fuzzified for membership functions that represent linguistic variables as low exposure, medium exposure and high exposure. After representing the membership grade in a RGB (red, green and blue) image it was possible to visualize the radiation level in the area of exposure. When compared to data from the region, results demonstrated the good efficiency of the technique here employed for the representation of areas with high radioactivity levels. The image obtained also provided important information about those areas where exposure to radiation is more pronounced. Hence, the fuzzy map can be applied in decision-making of experts when a risk situation is identified. (author)

  12. RADIU-226 CONTENT IN SOIL OF THE HIGH NATURAL BACKGROUND RADIATION AREA OF RAMSAR (IRAN

    Directory of Open Access Journals (Sweden)

    B.Khademi

    1978-11-01

    Full Text Available The existence of a high natural radiation area in the northern part of Iran (Ramsar is proved. Ra 226 in soil is measured. The results are: minimum 23.5 pCi/g and maximum 999 pCi/g soil. Environmental radioactivity is from 0.1 to 5 mr/h.

  13. Hybrid radiation background monitoring in operational control and forecasting of environmental contamination by nuclear power station discharges

    International Nuclear Information System (INIS)

    Rapid developments in nuclear power have stimulated research on monitoring and forecasting environmental radiation pollution (ERP), and in particular the amounts, compositions, and distributions of radionuclides in the environment. A conceptual model is presented for hybrid environmental radiation pollution monitoring. When there is an emergency, the model operates in a fashion most closely corresponding to the actual meteorological conditions, and the ERP data given by the model enable one to distinguish changes due to the man-made component from random fluctuations in the natural background. The measurement system in general includes mobile and stationary data-acquisition facilities linked by wire or radio to the central point. The system also accumulates and stores data on the radiation environment, which are edited on the basis of radioactive, chemical, and other transformations. The purpose of hybrid monitoring is ultimately to analyze trends in order to detect elevated discharges and thus to output data to the regional monitoring system

  14. Biological effects of high level natural background radiation on human population residing in Kerala coast, South West India

    International Nuclear Information System (INIS)

    The populations residing in Kerala coast are exposed to elevated natural background radiation since many generations. Extensive studies conducted by Bio-Medical group, Bhabha Atomic Research Center have generated wealth of data from this area dealing with epidemiology, monitoring the newborns for malformations, Health Audit Survey, Dosimetry and biological studies using cytogenetic and molecular biology techniques. Our studies on congenital malformations and chromosomal anomalies in children born to parents residing in High Level Natural Radiation Areas in Kerala have not shown any significant difference from normal radiation areas. Screening of over 1,25,000 consecutively born children showed an incidence rate which is comparable in both areas. Other factors such as consanguinity, maternal age and gravida status are more significant contributors than radiation dose to the risk for having malformation in child. Radiation prevalent in the HLNRA is in the dose range of above 1.5 to about 50 mGy per year which translates to doses in the range of nGy per hour. This clearly indicate the number of cells exposed to radiations will be one in few thousand or ten thousands. This throws up challenges in our capability to investigate the effects of radiation on cells. It has become imperative to develop and exploit techniques which will detect responses in single cells and would be able screen large number of cells at a time. Developments in cell biology and molecular biology are now giving us these capabilities. Use of flowcytometer and next generation sequencing would enable us to address many of these questions and provide meaningful approaches to understand the effects of such low dose radiation

  15. Particle and synchrotron radiation backgrounds at CESR-B: Learning from CLEOII/CESR

    International Nuclear Information System (INIS)

    Expectations for interaction-region (IR) backgrounds at the proposed Cornell CESR-B collider are reviewed in the light of experience gained at the currently operating CLEOII/CESR complex. Although CLEOII coexists with beam currents which are only 10 percent of CESR-B's, it is the world's highest luminosity electron-positron facility; it contains essential features of the generic B-factory collider: eg., CsI crystal calorimetry and small-cell drift chambers. CESR is strongly committed to increased luminosity and CLEO has a program underway to install a silicon vertex detector as well. These goals have provided additional incentives to understand IR backgrounds

  16. The Very High Background Radiation Area in Ramsar, Iran: Public Health Risk or Signal for a Regulatory Paradigm Shift?

    Energy Technology Data Exchange (ETDEWEB)

    Karam, P. Andrew [Univ. of Rochester, Rochester, NY (United States); Mortazavi, S.M. Javad [Rafsanjan Univ. of Medical Sciences (Iran, Islamic Republic of). Medical Physics Dept.

    2001-07-01

    Ramsar, a city on the Caspian Sea in northern Iran hosts the highest measured natural background radiation levels in the world. These are due to the local geology and hydrogeology and, in some places, deliver radiation doses far in excess of those recommended for radiation workers. A population of about 2000 is exposed to average annual radiation levels of 10.2 mGy/yr and the highest recorded doses are about 260 mGy/yr. These high radiation levels are due to the deposition of {sup 226}Ra in local rocks and, because these rocks are used in the construction of many local houses, interior radiation levels are often similar to those found outside. The presence of areas such as Ramsar raises an interesting public health policy question: Is it necessary to relocate the inhabitants to areas of lower natural background radiation levels in the interests of public health? According to the linear, no-threshold (LNT) hypothesis, there is no doubt that relocating the population of Ramsar will result in a reduction in cancer incidence. Therefore, under any reasonable policy based on the LNT hypothesis, the public health is best served by relocating many of Ramsar's inhabitants to other areas along the Caspian Sea. At present, there is no reliable epidemiological data on cancer incidence among the inhabitants of Ramsar's high background radiation areas (HBRAs), but local physicians feel that local cancer incidence rates are lower than in neighboring cities. Furthermore, preliminary results indicate that there is a statistically significant radio adaptation in the inhabitants of Ramsar. Interestingly, it seems that the frequency of chromosome aberrations in the lymphocytes of the inhabitants of Ramsar is no higher than the control areas. This important finding suggests that the cancer rate in Ramsar should be no higher than in other comparable parts of Iran. In other HBRAs such as Yangjiang, China it has been reported that mortality from all cancers and those from

  17. The Very High Background Radiation Area in Ramsar, Iran: Public Health Risk or Signal for a Regulatory Paradigm Shift?

    International Nuclear Information System (INIS)

    Ramsar, a city on the Caspian Sea in northern Iran hosts the highest measured natural background radiation levels in the world. These are due to the local geology and hydrogeology and, in some places, deliver radiation doses far in excess of those recommended for radiation workers. A population of about 2000 is exposed to average annual radiation levels of 10.2 mGy/yr and the highest recorded doses are about 260 mGy/yr. These high radiation levels are due to the deposition of 226Ra in local rocks and, because these rocks are used in the construction of many local houses, interior radiation levels are often similar to those found outside. The presence of areas such as Ramsar raises an interesting public health policy question: Is it necessary to relocate the inhabitants to areas of lower natural background radiation levels in the interests of public health? According to the linear, no-threshold (LNT) hypothesis, there is no doubt that relocating the population of Ramsar will result in a reduction in cancer incidence. Therefore, under any reasonable policy based on the LNT hypothesis, the public health is best served by relocating many of Ramsar's inhabitants to other areas along the Caspian Sea. At present, there is no reliable epidemiological data on cancer incidence among the inhabitants of Ramsar's high background radiation areas (HBRAs), but local physicians feel that local cancer incidence rates are lower than in neighboring cities. Furthermore, preliminary results indicate that there is a statistically significant radio adaptation in the inhabitants of Ramsar. Interestingly, it seems that the frequency of chromosome aberrations in the lymphocytes of the inhabitants of Ramsar is no higher than the control areas. This important finding suggests that the cancer rate in Ramsar should be no higher than in other comparable parts of Iran. In other HBRAs such as Yangjiang, China it has been reported that mortality from all cancers and those from leukemia, breast and

  18. Study of the low energy background radiation and the effects of the 222Rn in the LSD underground experiment

    International Nuclear Information System (INIS)

    A systematic study of the low energy background radiation has been performed under several conditions in the underground experiment at Mt. Blanc laboratory. The information gathered using three different types of detectors: LSD (90 tons of liquid scintillator) with energy threshold Eth > 800 KeV, Nal (5'x5') with Eth > 220 KeV and a Radon-meter (alpha spectrometer) running at the same time, has been analyzed during long and continuous time periods. It was found that the variations in counting rate of the low energy background is due to the presence of 222Rn in the laboratory room. Three types of variations were found: 1) a correlation with the tunnel ventilation system, 2) a daily modulation and 3) a sporadic increase in the counting rate not correlated to any man-made intervention. We emphasize the importance of knowing the background and its variations in underground laboratories dedicated to low energy neutrinos and dark mater searches. (orig.)

  19. Studies of Background Levels for the NIF Yield Diagnostics from Neutron and Gamma Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Song, P; Eder, D; Moran, M; Landen, O; O' Brien, D; Hsing, W

    2007-08-27

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is nearing completion of construction and is preparing for the National Ignition Campaign (NIC) with potentially significant yield in 2010. The design of a wide range of yield diagnostics in and outside the target-bay of the NIF must consider scattered background neutrons and neutron-induced gamma rays to measure neutrons and x-rays from target. The large and complex target chamber and facility make the calculation of scattered neutrons and gamma rays extremely challenging. The NIF was designed with shielded locations for many of the yield diagnostics including the neutron alcove and four diagnostic mezzanines. Accurate calculation of the background levels in these shielded locations requires advanced Monte Carlo techniques, e.g., variance reduction. Placement, size, and materials of collimators on the line of sight (LOS) through the shielding must be evaluated to trade off signal levels and unwanted backgrounds. The background at these locations is also affected by neutrons that pass through the laser beam tubes and scatter off of structures and walls in the switch yards. Detailed 3D Monte Carlo analyses are performed to determine neutron and gamma fluxes for some of the yield diagnostics.

  20. Variation of natural background radiation in the Federal Republic of Germany

    International Nuclear Information System (INIS)

    Within the framework of a research project supported by the Federal Minister of the Interior, 30,000 measurements were conducted with scintillation dosimeters of the same type in 10 institutions distributed all over the Federal Republic of Germany, determining the local rate of gamma radiation in building (mean values). In addition, 25,000 measurements of the local dose rate of gamma radiation in the free environment as well as approximately 600 measurements were performed via gamma spectroscopy of the specific content of natural radioactive substances in building materials. The dose rate measurements were centrally evaluated by an electronic data processing system, whereby regional differences, differences depending on age and type of buildings, differences depending on the content of natural radioactive substances in building materials were taken into consideration. The results of this research program are discussed

  1. Excess cancer risk among inhabitants in the high background radiation area of Yangjiang, China (1979-1998)

    International Nuclear Information System (INIS)

    The mortality among the inhabitants in the high background radiation area (HBRA) of Yangjiang, Guangdong Province, China was first reported internationally in 1980. Most of the inhabitants lived in the study areas for six or more generations. External radiation dose from the natural sources, including thorium, was estimated to be 2.10 mSv/a in the HBRA and 0.77 mSv/a in the control area (CA). Regarding internal radiation exposure, it was estimated that internal radiation doses in the HBRA and the CA were 4.27 mSv/a and 1.65 mSv/a, respectively. The epidemiological studies had failed to show any excess risk of cancer. The major purpose of the present study is to evaluate the effects of continuous low dose-rate exposure to low-linear energy transfer (LET) ionizing radiation on excess cancer risk. In this report, we present the results of cancer mortality analysis during the period 1979-1998, adding 3 years to the previous reports. (author)

  2. Semi-numeric simulations of helium reionization and the fluctuating radiation background

    CERN Document Server

    Dixon, Keri L; Mesinger, Andrei

    2013-01-01

    Recent He II Lyman-alpha forest observations from 2.0 2.7. These results point to a fluctuating He-ionizing background, which may be due to the end of helium reionization of this era. We present a fast, semi-numeric procedure to approximate detailed cosmological simulations. We compute the distribution of dark matter halos, ionization state of helium, and density field at z = 3 in broad agreement with recent simulations. Given our speed and flexibility, we investigate a range of ionizing source and active quasar prescriptions. Spanning a large area of parameter space, we find order-of-magnitude fluctuations in the He II ionization rate in the post-reionization regime. During reionization, the fluctuations are even stronger and develop a bimodal distribution, in contrast to semi-analytic models and the hydrogen equivalent. These distributions indicate a low-level ionizing background even at significant He II fractions.

  3. Small-scale primordial magnetic fields and anisotropies in the cosmic microwave background radiation

    International Nuclear Information System (INIS)

    It is shown that small-scale magnetic fields present before recombination induce baryonic density inhomogeneities of appreciable magnitude. The presence of such inhomogeneities changes the ionization history of the Universe, which in turn decreases the angular scale of the Doppler peaks and increases Silk damping by photon diffusion. This unique signature could be used to (dis)prove the existence of primordial magnetic fields of strength as small as B ≅ 10−11 Gauss by cosmic microwave background observations

  4. Small-scale primordial magnetic fields and anisotropies in the cosmic microwave background radiation

    Energy Technology Data Exchange (ETDEWEB)

    Jedamzik, Karsten [Laboratoire de Univers et Particules, UMR5299-CNRS, Université de Montpellier II, F-34095 Montpellier (France); Abel, Tom, E-mail: karsten.jedamzik@um2.fr, E-mail: tabel@slac.stanford.edu [Kavli Institute for Particle Astrophysics and Cosmology, SLAC/Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2013-10-01

    It is shown that small-scale magnetic fields present before recombination induce baryonic density inhomogeneities of appreciable magnitude. The presence of such inhomogeneities changes the ionization history of the Universe, which in turn decreases the angular scale of the Doppler peaks and increases Silk damping by photon diffusion. This unique signature could be used to (dis)prove the existence of primordial magnetic fields of strength as small as B ≅ 10{sup −11} Gauss by cosmic microwave background observations.

  5. Assessment of indoor radiation dose received by the residents of natural high background radiation areas of coastal villages of Kanyakumari district, Tamil Nadu, India

    Energy Technology Data Exchange (ETDEWEB)

    Deva Jayanthi, D., E-mail: d.devajayanthi@gmail.co [Department of Physics, Women' s Christian College, Nagercoil 629001 (India); Maniyan, C.G. [Environmental Assessment Division, BARC, Mumbai 400085 (India); Perumal, S. [Department of Physics and Research Centre, S.T.Hindu College, Nagercoil 629002 (India)

    2011-07-15

    Radiation exposure and effective dose received through two routes of exposure, viz. external and internal, via inhalation, by residents of 10 villages belonging to Natural High Background Radiation Areas (NHBRA) of coastal regions of Kanyakumari District and Tamil Nadu in India were studied. While the indoor gamma radiation levels were monitored using Thermo Luminescent Dosimeters (TLDs), the indoor radon and thoron gas concentrations were measured using twin chamber dosimeters employing Solid State Nuclear Track Detectors (SSNTDs, LR-115-II). The average total annual effective dose was estimated and found to be varying from 2.59 to 8.76 mSv. -- Highlights: {yields} The effective dose received by the villages of Natural High Background Area (NHBRA) such as Enayam, Midalam and Mel Midalam is high when compared with other study areas. {yields} The high dose indicates higher concentration of radioactive nuclides like Thorium and Uranium in the soil. {yields} As radiation is harmful to human life, the external and internal doses can be reduced by removing the monazite content present in the soil by mineral separation. {yields} Contribution from vegetables, fruits, fish and other non vegetarian items are also being examined. {yields} These results along with other socio-economic factors can throw considerable light on the epidemiological impacts due to low levels of chronic exposure.

  6. Assessment of indoor radiation dose received by the residents of natural high background radiation areas of coastal villages of Kanyakumari district, Tamil Nadu, India

    International Nuclear Information System (INIS)

    Radiation exposure and effective dose received through two routes of exposure, viz. external and internal, via inhalation, by residents of 10 villages belonging to Natural High Background Radiation Areas (NHBRA) of coastal regions of Kanyakumari District and Tamil Nadu in India were studied. While the indoor gamma radiation levels were monitored using Thermo Luminescent Dosimeters (TLDs), the indoor radon and thoron gas concentrations were measured using twin chamber dosimeters employing Solid State Nuclear Track Detectors (SSNTDs, LR-115-II). The average total annual effective dose was estimated and found to be varying from 2.59 to 8.76 mSv. -- Highlights: → The effective dose received by the villages of Natural High Background Area (NHBRA) such as Enayam, Midalam and Mel Midalam is high when compared with other study areas. → The high dose indicates higher concentration of radioactive nuclides like Thorium and Uranium in the soil. → As radiation is harmful to human life, the external and internal doses can be reduced by removing the monazite content present in the soil by mineral separation. → Contribution from vegetables, fruits, fish and other non vegetarian items are also being examined. → These results along with other socio-economic factors can throw considerable light on the epidemiological impacts due to low levels of chronic exposure.

  7. Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body

    OpenAIRE

    Pattison, John E; Hugtenburg, Richard P.; Green, Stuart

    2009-01-01

    Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy ...

  8. The modulating impact of illumination and background radiation on 8 Hz-induced infrasound effect on physicochemical properties of physiolagical solution.

    Science.gov (United States)

    Baghdasaryan, Naira; Mikayelyan, Yerazik; Barseghyan, Sedrak; Dadasyan, Erna; Ayrapetyan, Sinerik

    2012-12-01

    At present, when the level of background ionizing radiation is increasing in a number of world locations, the problem of the study of biological effect of high background radiation becomes one of the extremely important global problems in modern life sciences. The modern research in biophysics proved that water is a most essential target, through which the biological effects of ionizing and non-ionizing radiations are realized. Therefore, there is no doubt about the strong dependency of non-ionizing radiation-induced effect on the level of background radiation. Findings have shown that illumination and background radiation have a strong modulation effect on infrasound-induced impacts on water physicochemical properties, which could also have appropriate effect on living organisms. PMID:22676714

  9. Determination of Absorbed and Effective Dose from Natural Background Radiation around a Nuclear Research Facility

    Directory of Open Access Journals (Sweden)

    M. A. Musa

    2011-01-01

    Full Text Available Problem statement: This study presents result of outdoor absorbed dose rate and estimated effective dose from the naturally occurring radionuclides 232Th and 238U series 40K, around a Nuclear Research Reactor at the Centre for Energy Research and Training (CERT, Zaria, Nigeria. Approach: A high-resolution in situ ?-ray spectrometry was used to carry out the study. CERT houses a 30Kw Research Reactor and other neutron and gamma sources for Research and Training. Results: The values of absorbed dose rate in air for 232Th, 238U and 40K range from 8.2 ± 2.5-24.5 ± 3.6 nGy h?1, 1.9 ± 1.2-4.6 ± 2.5 nGy h?1 and 12.2 ± 5-38 ± 6.7n Gy h?1 respectively . The estimated total annual effective dose outdoor for the sites range from 27.3-79.9 ?Sv y?1.Conclusions: This showed that radiation exposure level for the public is lower than the recommended value of 1 mSv y?1.Hence, the extensive usage of radioactive materials within and around CERT does not appear to have any impact on the radiation burden of the environment.

  10. Probing the Cosmic X-Ray and MeV Gamma-Ray Background Radiation through the Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Yoshiyuki [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Murase, Kohta [Inst. for Advanced Study, Princeton, NJ (United States). School of Natural Sciences; Madejski, Grzegorz M. [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Uchiyama, Yasunobu [Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; SLAC National Accelerator Lab., Menlo Park, CA (United States); Rikkyo Univ., Tokyo (Japan). Dept. of Physics

    2013-09-24

    While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once the future hard X-ray all sky satellites achieve the sensitivity better than 10-12 erg/cm2/s-1 at 10-30 keV or 30-50 keV - although this is beyond the sensitivities of current hard X-ray all sky monitors - angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

  11. Reduction of Radioactive Backgrounds in Electroformed Copper for Ultra-Sensitive Radiation Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Eric W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Aalseth, Craig E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Farmer, Orville T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hossbach, Todd W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liezers, Martin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Miley, Harry S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Overman, Nicole R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Reeves, James H. [Reeves and Son LLC., Richland, WA (United States)

    2014-07-07

    Abstract Ultra-pure construction materials are required for the next generation of neutrino physics, dark matter and environmental science applications. These new efforts require materials with purity levels at or below 1 uBq/kg 232Th and 238U. Yet radiometric analysis lacks sensitivity below ~10 uBq/kg for the U and Th decay chains. This limits both the selection of clean materials and the validation of purification processes. Copper is an important high-purity material for low-background experiments due to the ease with which it can be purified by electrochemical methods. Electroplating for purification into near-final shapes, known as electroforming, is one such method. Continued refinement of the copper electroforming process is underway, for the first time guided by an ICP-MS based assay method that can measure 232Th and 238U near the desired purity levels. An assay of electroformed copper at 10 uBq/kg for 232Th has been achieved and is described. The implications of electroformed copper at or better than this purity on next-generation low-background experiments are discussed.

  12. Reduction of radioactive backgrounds in electroformed copper for ultra-sensitive radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, E.W., E-mail: eric.hoppe@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Aalseth, C.E.; Farmer, O.T.; Hossbach, T.W.; Liezers, M.; Miley, H.S.; Overman, N.R. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Reeves, J.H. [Reeves and Son LLC, 10 Albert Ave., Richland, WA 99352 (United States)

    2014-11-11

    Ultra-pure construction materials are required for the next generation of neutrino physics, dark matter and environmental science applications. These materials are also important for use in high-purity germanium spectrometers used in screening materials for radiopurity. The next-generation science applications require materials with radiopurity levels at or below 1 μBq/kg {sup 232}Th and {sup 238}U. Yet radiometric analysis lacks sensitivity below ∼10 μBq/kg for the U and Th decay chains. This limits both the selection of clean materials and the validation of purification processes. Copper is an important high-purity material for low-background experiments due to the ease with which it can be purified by electrochemical methods. Electroplating for purification into near-final shapes, known as electroforming, is one such method. Continued refinement of the copper electroforming process is underway, for the first time guided by an ICP-MS based assay method that can measure {sup 232}Th and {sup 238}U near the desired purity levels. An assay of electroformed copper at a μBq/kg level has been achieved and is described. The implications of electroformed copper at or better than this purity on next-generation low-background experiments are discussed.

  13. A case-control study of nasopharyngeal carcinoma among inhabitants in high background radiation areas of Yangjiang, China

    International Nuclear Information System (INIS)

    Objective: The purpose of the study was to confirm and explore main risk factors of nasopharyngeal carcinoma (NPC) in cohort members of the investigated areas, and evaluate effects of confounding factors on cancer risk associated with exposure to high background radiation. Methods: The deceased cases of NPC during the period of 1987-1995 were selected as study subjects for each of whom two controls were randomly selected from potential control subjects who died from causes other than malignant tumors and external causes, and matched for sex and years of birth and death (within 5 years). Using structure questionnaire, the relevant information including socioeconomic status, dietary habits, smoking and alcohol consumption, history of illness, agricultural use of pesticide, medical X-ray exposure and familial history of NPC were collected. The odds ratio (OR) was used as a measure of association between NPC and the risk factors. Results: 102 cases and 202 controls were successfully investigated. Single factor conditional logistic regression analysis showed that the occurrence of NPC was closely positively associated with intake of salted fish, pickles, fermented soybeans, cured meats, history of chronic rhinitis and familial history of NPC. Further multiple conditional logistic regression analysis turned out that intake of salted fish, history of chronic rhinits and familial history of NPC were the independent risk factors of NPC. After controlling for history of chronic rhinits and familial history of NPC, the results based on multiple conditional logistic regression analysis from high background radiation, intake of salted fish and fermented soybeans, tobacco smoking and alcohol consumption showed that only intake of salted fish was a significant risk factor (OR = 2.8, 95% CI 1.52-5.18), tobacco smoking (OR = 1.2, 95% CI 0.65-2.22), alcohol consumption (OR = 0.83, 95% CI 0.38-1.78) and exposure to high background radiation (OR= 0.86, 95% CI 0.44-1.68) did not

  14. Large-scale anisotropy of the cosmic background radiation due to primordial density and gravitational-wave perturbations

    International Nuclear Information System (INIS)

    The possibility that part of the recently discovered large-scale anisotropy of the cosmic background radiation is aroused from primordial density and gravitational-wave perturbations through the Sachs-Wolfe effect, is investigated in both closed and open models in connection with the severe constraint for the small-scale anisotropy. It is concluded that, in order to explain the dipole anisotropy of the order of 10-3 by density perturbations, closed models and density fluctuation spectrums not steeper than ''white noise'' one are required, and that gravitational-wave perturbations cannot contribute to the possible quadrupole anisotropy of the order of 10-4. (author)

  15. Survey of Gamma Dose and Radon Exhalation Rate from Soil Surface of High Background Natural Radiation Areas in Ramsar, Iran

    Directory of Open Access Journals (Sweden)

    Rouhollah Dehghani

    2013-09-01

    Full Text Available Background: Radon is a radioactive gas and the second leading cause of death due to lung cancer after smoking. Ramsar is known for having the highest levels of natural background radiation on earth. Materials and Methods: In this research study, 50 stations of high radioactivity areas of Ramsar were selected in warm season of the year. Then gamma dose and radon exhalation rate were measured.Results: Results showed that gamma dose and radon exhalation rate were in the range of 51-7100 nSv/hr and 9-15370 mBq/m2s, respectively.Conclusion: Compare to the worldwide average 16 mBq/m2s, estimated average annual effective of Radon exhalation rate in the study area is too high.

  16. Effect of intense background radiation on the sensitivity of a laser receiver with an iodine active quantum filter

    International Nuclear Information System (INIS)

    The effect of background light on the sensitivity of a laser receiver with an iodine active quantum filter (λ=1.315 μm) was theoretically and experimentally investigated. Upon the reception of a 40-ns pulsed signal against the background of 2.5-fold attenuated radiation of a pulsed light source with a brightness temperature of 4 x 104 K, the sensitivity of this receiver for a signal-to-noise ratio of three and a diffraction-limited acceptance angle was experimentally shown to be equal to 20 photons, which exceeds the quantum limit by about a factor of two. This is consistent with the results of theoretical treatment and suggests that upon the detection of optical signals against the background of the solar disk, the sensitivity of this receiver should decrease by only 12%. This receiver was compared with a receiver employing a photomultiplier of the visible range. Upon the reception of optical signals with the same parameters against the background of the solar disk and an interference filter with a transmission band width of 5 nm, the sensitivity of a receiver equipped with an FEU-115 photomultiplier was shown to be equal to about 1400 photons for a signal-to-noise ratio of three. (laser applications and other topics in quantum electronics)

  17. Background Radiation Survey of the Radiological/Nuclear Countermeasures Test and Evaluation Center

    International Nuclear Information System (INIS)

    In preparation for operations at the Radiological/Nuclear Countermeasures Test and Evaluation Complex (Rad/NucCTEC), the Department of Homeland Security Domestic Nuclear Detection Office (DHS/DNDO) requested that personnel from the Remote Sensing Laboratory (RSL) conduct a survey of the present radiological conditions at the facility. The measurements consist of the exposure rate from a high-pressure ion chamber (HPIC), high-resolution spectra from a high-purity germanium (HPGe) system in an in situ configuration, and low-resolution spectra from a sodium iodide (NaI) detector in a radiation detection backpack. Measurements with these systems were collected at discrete locations within the facility. Measurements were also collected by carrying the VECTOR backpack throughout the complex to generate a map of the entire area. The area was also to be surveyed with the Kiwi (an array of eight-2-inch x 4-inch x 16-inch NaI detectors) from the Aerial Measuring Systems; however, conflicts with test preparation activities at the site prevented this from being accomplished.

  18. Background Radiation Survey of the Radiological/Nuclear Countermeasures Test and Evaluation Center

    Energy Technology Data Exchange (ETDEWEB)

    Colin Okada

    2010-09-16

    In preparation for operations at the Radiological/Nuclear Countermeasures Test and Evaluation Complex (Rad/NucCTEC), the Department of Homeland Security Domestic Nuclear Detection Office (DHS/DNDO) requested that personnel from the Remote Sensing Laboratory (RSL) conduct a survey of the present radiological conditions at the facility. The measurements consist of the exposure rate from a high-pressure ion chamber (HPIC), high-resolution spectra from a high-purity germanium (HPGe) system in an in situ configuration, and low-resolution spectra from a sodium iodide (NaI) detector in a radiation detection backpack. Measurements with these systems were collected at discrete locations within the facility. Measurements were also collected by carrying the VECTOR backpack throughout the complex to generate a map of the entire area. The area was also to be surveyed with the Kiwi (an array of eight-2-inch x 4-inch x 16-inch NaI detectors) from the Aerial Measuring Systems; however, conflicts with test preparation activities at the site prevented this from being accomplished.

  19. Dietary intake of naturally occurring radionuclides from thorium series, uranium series and potassium-40 in high background radiation areas of Manavalakurichi, Tamil Nadu

    International Nuclear Information System (INIS)

    Natural background radiation is a major source of human exposure to radiation. The source of background radiation is due to monazite containing naturally occurring radionuclides like thorium and uranium. These natural radionuclides are found in all environmental matrices like rocks, soil, water, and dietary sources. The intake of natural radionuclides to public would occur in ingestion pathway via dietary sources. The present study aims to evaluate the natural radionuclides in dietary sources from Manavalakurichi region, which is a High Background Radiation Area's (HBRA's) in Tamil Nadu. The natural radionuclides such as Uranium (238U and 234U), Radium (226Ra and 228Ra), Polonium (210Po) and Potassium (40K) in the dietary products were analyzed in various dietary sources and computed the ingestion dose for different age group of public residing in and around Manavalakurichi. The study can act as existing data for Indian population living in the high radiation background areas

  20. An investigation of the submillimeter background radiation using SCUBA and Spitzer

    CERN Document Server

    Dye, S; Ashby, M L N; Huang, J S; Webb, T M A; Barmby, P; Lilly, S; Brodwin, M; McCracken, H; Egami, E; Fazio, G G

    2005-01-01

    We investigate the redshift dependence of the contribution to the extragalactic far-infrared/sub-millimeter background from galaxies detected by the Spitzer Space Telescope at 8um and 24um. Using seven-band optical to mid-infrared photometry, we estimate photometric redshifts for the Spitzer sources which appear to be mostly L* galaxies at a median redshift of z=1.0. These sources, extracted from deep 8um and 24um mosaics of the CUDSS 14-hour field with 5sigma limits of 5.8uJy and 70uJy respectively, exhibit significant 850um and 450um emission as observed by SCUBA. At 850um, after removing >=4sigma sources and those securely identified in our previous cross-matching paper, we measure stacked flux at the significance level of 4.4sigma and 2.9sigma from the full 8um and 24um galaxy catalogue respectively. At 450um, flux is detected from all 8um galaxies at the level of 3.5sigma, while there is no significant emission from the 24um galaxies. We find that the 850um flux is emitted almost exclusively at z>~1.3 fr...

  1. Long-term TLD measurements of environmental background radiation in the New York City Area

    International Nuclear Information System (INIS)

    The results of month-long TLD measurements at seven locations within 150 km of New York City are reported for 12 years at a few locations and for up to 18 years at others. At some locations, multiple dosimeters were deployed to acquire concurrent indoor and outdoor measurements. The sites were varied and include an urban high-rise residence, three suburban backyards, a rural hillside, and the wooded outskirts of a nuclear power plant (nonoperational). Long-term mean dose rates in air ranged from 50.8 to 123.1 nGy h-1 (5.8 to 14.1 μR h-1) across the area. The typical seasonal dose rate in air variations are presented for two of the sites and are briefly discussed in terms of soil conditions. The data indicate that it is possible to achieve monthly variations from the long-term mean as high as 20 to 40%. One of these locations was monitored for indoor (2 floors) and outdoor air dose rates. This allowed for a time series comparison to be performed illustrating the changing contribution of terrestrial radiation to the total dose rate relative to the steady building material-derived radioactivity. This site also permitted the calculation of indoor/outdoor ratios for two floors. Another suburban location yielded an indoor/outdoor ratio using ground floor dose-rate-in-air measurements. Also presented are mean annual dose rates in air showing a long-term decrease at some locations. A statistical Kendall test was performed to quantify the magnitude of the decrease. A definitive explanation of this trend requires further study

  2. Train-borne measurements of background radiation along the railways in New Zealand

    International Nuclear Information System (INIS)

    A survey done in New Zealand to estimate the outdoor gamma-ray dose rates using a technique of an improved version of one used previously in Australia was reported together with the cosmic-ray dose rates estimated from atmospheric pressure data. A battery-operated portable digital NaI(Tl) (1''φ x 2'') scintillation survey-meter was used for measurement on board regular service of passenger trains. The calibration of count rates into absorbed dose rates was done through simultaneous measurements with a 3''φ x 2'' NaI(Tl) scintillation spectrometer at different dose levels in a natural outdoor environment. Since the survey was carried out inside the train, data were converted to ones outdoors using the regression line. Influence of cliffs, tunnels and waters was corrected by author's model based on the place of the detector. For cosmic-ray dose rates, theoretical data by O'Brien were used. The survey was performed over a period of 3 days, from 22 to 24, February 1998. The route was that from Invercargill to Auckland through Picton/Wellington which was of 1,617 km distance, of which measured data were presented graphically. The mean of the terrestrial gamma-ray dose rates was found to be 62.7 nGy/h. The data were compared with ones by Matthews and found to scatter within the range of their statistical errors, which thus suggested that the data represented the outdoor radiation levels fairly well. (K.H.)

  3. The imprint of the cosmic supermassive black hole growth history on the 21 cm background radiation

    Science.gov (United States)

    Tanaka, Takamitsu L.; O'Leary, Ryan M.; Perna, Rosalba

    2016-01-01

    The redshifted 21 cm transition line of hydrogen tracks the thermal evolution of the neutral intergalactic medium (IGM) at `cosmic dawn', during the emergence of the first luminous astrophysical objects (˜100 Myr after the big bang) but before these objects ionized the IGM (˜400-800 Myr after the big bang). Because X-rays, in particular, are likely to be the chief energy courier for heating the IGM, measurements of the 21 cm signature can be used to infer knowledge about the first astrophysical X-ray sources. Using analytic arguments and a numerical population synthesis algorithm, we argue that the progenitors of supermassive black holes (SMBHs) should be the dominant source of hard astrophysical X-rays - and thus the primary driver of IGM heating and the 21 cm signature - at redshifts z ≳ 20, if (i) they grow readily from the remnants of Population III stars and (ii) produce X-rays in quantities comparable to what is observed from active galactic nuclei and high-mass X-ray binaries. We show that models satisfying these assumptions dominate over contributions to IGM heating from stellar populations, and cause the 21 cm brightness temperature to rise at z ≳ 20. An absence of such a signature in the forthcoming observational data would imply that SMBH formation occurred later (e.g. via so-called direct collapse scenarios), that it was not a common occurrence in early galaxies and protogalaxies, or that it produced far fewer X-rays than empirical trends at lower redshifts, either due to intrinsic dimness (radiative inefficiency) or Compton-thick obscuration close to the source.

  4. Final report and evaluation of the SAWORA research program on background radiation levels from natural origin in The Netherlands

    International Nuclear Information System (INIS)

    In order to study the various factors which determine the dose resulting from background radiation, in particular for the indoor situation, the SAMORA-programme was initiated in 1982. The various aspects studied were: 1) a determination of the current background radiation level, for the indoor as well as the outdoor situation; 2) an inventory of the radioactivity of the building materials; 3) the radioecological aspects from fly-ash and gypsum deposits; 4) a risk estimation of lung tumour induction at low doses and for low dose rates; 5) technical factors determining the effective dose equivalent. In this report the connection of the results derived in the different studies will be discussed. From the study on radioconcentration it became clear that the indoor concentration is strongly determined by the concentration in the crawl space. On the basis of the results of the programme an estimation of the lung tumour risk for the Dutch population is presented. For the current levels it is calculated that the risk is approximately 2.1 lung tumours per 100.000 persons. Since in 1982 the mean lung tumour death rate for the Dutch population was 56.8 per 100.000, this result demonstrates that the calculated contribution is relatively low (4%). Furthermore it is calculated that the maximum increase of this contribution as a result of the introduction of active gypsum building materials will be of the order of 1%. (Auth.)

  5. Imperceptible effect of radiation based on stable type chromosome aberrations accumulated in the lymphocytes of residents in the high background radiation area in China

    International Nuclear Information System (INIS)

    Cytogenetic investigation of stable type aberrations (translocations) was performed with our improved methods in 6 children and 15 elderly persons in a high background radiation area (HBRA) in China, and in 8 children and 11 elderly persons in a control area. The total numbers of cells analyzed in elderly persons were 68,297 in HBRA and 35,378 in controls and in children were 45,535 in HBRA and 56,198 in controls. On average 5138 cells per subject were analyzed. The variation in the frequencies of translocations per 1000 cells was small in children while it was large in elderly persons. No significant difference was found in the frequencies between HBRA and control (P>0.05, Mann-Whitney U test). On the other hand, correlation between age and translocation frequencies was significant at the 1% level (rs=0.658 with 37DF, Spearman rank correlation test). The contribution of an elevated level of natural radiation in HBRA in China to the induction of stable type chromosome aberrations does not have a significant effect compared with the contribution of chemical mutagens and/or metabolic factors. The present study suggests that the probability of the risk of causing malignant and/or congenital diseases by the increased amount of radiation is imperceptible in HBRA where the level of natural radiation is 3 to 5 times higher than that in the control area. (author)

  6. Study of the natural radiation background affected on the human body in some areas of Viet Nam

    International Nuclear Information System (INIS)

    The author had studied the natural radiation background in 68 districts belong 40 provinces and cities of Vietnam from 2002 to 2005. The estimated results clearly show that the average external irradiation dose levels and the average annual external radiation equivalent dose affected on the human body are 0.181± 0.0189 μSv/h and 1599 ± 171.8 μSv/year respectively, both are in normal limit; the highest levels are in Lai Chau district (Lai Chau province); the lowest levels are in Buon Ma Thuot city (DakLak province), Phuoc Son district (Quang Nam province), Tan An district (Long An province). The radon concentration in the human being and the average annual internal inhalation irradiation equivalent dose affected on the human beings are 26.9 ± 15.89 Bq/m3 and 392.88 ± 231.99 μSv/year respectively; the maximums are in Nha Trang city (Khanh Hoa province), Bac Binh district (Binh Phuoc province); the minimums are in Vung Tau city (Ba Ria- Vung Tau province), Tan An district (Long An province), Rach Gia district (Kien Giang province). The terrestrial radionuclide concentrations in the cereals, foodstuffs (rice, meat, vegetables), water, earth and the average annual internal irradiation equivalent dose are 829.2 ± 38.06 Bq/kg and 229.3 ± 67.70 μSv/year respectively; the highest levels are in Phong Tho district (Lai Chau province), Dien Bien city; the lowest levels are in Dong Xoai district (Binh Phuoc province), Tan An district (Long An province). The average total annual natural radiation background effective equivalent dose level affected on the human body is 2206.9 ± 529.30 μSv/year; the highest levels are in Lai Chau district (Lai Chau province); the lowest levels are in Tan An district (Long An province). The 14 maps of Natural Radiation Background in several localized regions belong 40 provinces and cities of Viet Nam had been set up. These results can reserve for serviceman and public health in the both wartime and peacetime. (author)

  7. The interaction of natural background gamma radiation with depleted uranium micro-particles in the human body.

    Science.gov (United States)

    Pattison, John E

    2013-03-01

    In this study, some characteristics of the photo-electrons produced when natural background gamma radiation interacts with micron-sized depleted uranium (DU) particles in the human body have been estimated using Monte Carlo simulations. In addition, an estimate has been made of the likelihood of radiological health effects occurring due to such an exposure. Upon exposure to naturally occurring background gamma radiation, DU particles in the body will produce an enhancement of the dose to the tissue in the immediate vicinity of the particles due to the photo-electric absorption of the radiation in the particle. In this study, the photo-electrons produced by a 10 μm-size particle embedded in tissue at the centre of the human torso have been investigated. The mean energies of the photo-electrons in the DU particle and in the two consecutive immediately surrounding 2 μm-wide tissue shells around the particle were found to be 38, 49 and 50 keV, respectively, with corresponding ranges of 1.3, 38 and 39 μm, respectively. The total photo-electron fluence-rates in the two consecutive 2 μm-wide tissue layers were found to be 14% and 7% of the fluence-rate in the DU particle, respectively. The estimated dose enhancement due to one 10 μm-sized DU particle in 1 cm(3) of tissue was less than 2 in 10 million of the dose received by the tissue without a particle being present. The increase in risk of death from cancer due to this effect is consequently insignificant. PMID:23295360

  8. The interaction of natural background gamma radiation with depleted uranium micro-particles in the human body

    International Nuclear Information System (INIS)

    In this study, some characteristics of the photo-electrons produced when natural background gamma radiation interacts with micron-sized depleted uranium (DU) particles in the human body have been estimated using Monte Carlo simulations. In addition, an estimate has been made of the likelihood of radiological health effects occurring due to such an exposure. Upon exposure to naturally occurring background gamma radiation, DU particles in the body will produce an enhancement of the dose to the tissue in the immediate vicinity of the particles due to the photo-electric absorption of the radiation in the particle. In this study, the photo-electrons produced by a 10 μm-size particle embedded in tissue at the centre of the human torso have been investigated. The mean energies of the photo-electrons in the DU particle and in the two consecutive immediately surrounding 2 μm-wide tissue shells around the particle were found to be 38, 49 and 50 keV, respectively, with corresponding ranges of 1.3, 38 and 39 μm, respectively. The total photo-electron fluence-rates in the two consecutive 2 μm-wide tissue layers were found to be 14% and 7% of the fluence-rate in the DU particle, respectively. The estimated dose enhancement due to one 10 μm-sized DU particle in 1 cm3 of tissue was less than 2 in 10 million of the dose received by the tissue without a particle being present. The increase in risk of death from cancer due to this effect is consequently insignificant. (paper)

  9. Effects of smoking on chromosomes compared with those of radiation in a high-background radiation area and of environmental mutagenic factors in a large city

    International Nuclear Information System (INIS)

    Smoking is the most influential factor among the environmental mutagens to increase cancer incidence. In order to know how environmental mutagens affect the induction of translocations caused by smoking we analyzed the translocations in the lymphocytes of smokers and nonsmokers in a large city, Beijing, and compared them with those reported by us in a high background radiation area (HBRA) and in its control area (CA), remote villages, in the south of China. This paper is the review of our reported studies performed under China-Japan collaborative study on HBRA in China conducted by Prof. Tsutomu Sugahara, Japan, and Prof. Luxin Wei, China. (author)

  10. A case-control study of nasopharyngeal carcinoma in the high background radiation areas of Yangjiang, China

    Energy Technology Data Exchange (ETDEWEB)

    Zou Jianming; Zha Yongru [Guangdong Inst. of Prevention and Treatment of Occupational Diseases, Guangzhou (China); Sun Quanfu; Akiba, Suminori; Yuan Yongling; Tao Zufan; Wei Luxin; Sugahara, Tsutomu

    2000-10-01

    The main purposes of this study were to identify the major determinants of nasopharyngeal carcinoma (NPC) in the high-background radiation areas (HBRA) in Yangjiang, China and to evaluate their potential confounding effects on the NPC risk associated with exposure to high background radiation. A matched case-control study was conducted using those who died of NPC during the period 1987-1995. Two controls were randomly selected for each case from those who died from causes other than malignancies and external causes. Cases and their controls were matched with respect to sex and the years of birth and death ({+-}5 years). Study subjects' next-of-kin were interviewed using a standardized questionnaire to collect information on socioeconomic status, dietary habits, tobacco smoking and alcohol consumption, disease history, pesticide use, medical X-ray exposure, the family history of NPC and so on. We succeeded in interviewing 97 cases and 192 controls. Univariate conditional logistic regression analysis showed that NPC risk was associated with the consumption of salted fish, homemade pickles, and fermented soy beans, education levels, the history of chronic rhinitis, and the family history of NPC. Multivariate conditional logistic regression analysis revealed that education levels (Odds ratio (OR) for middle school or higher levels vs. no school education=3.8, 95% CI=1.2 to 11.8), salted fish intake (OR=3.2, 95% CI=1.7 to 6.1), the history of chronic rhinitis (OR=3.6, 95% CI=1.3 to 10.1), and the family history of NPC (OR=14.2, 95% CI=2.7 to 73.4) were independent risk factors of NPC. Tobacco smoking (OR=1.2, 95% CI=0.7 to 2.1), and alcohol consumption (OR=0.9, 95% CI=0.5 to 1.9) were not significantly related to NPC risk. The ORs of NPC risk comparing HBRA and a nearby control area before and after adjustment for the major risk determinants identified in the present study were 0.86 (95% CI=0.50 to 1.50) and 0.87 (95% CI=0.45 to 1.67), respectively. Salted fish

  11. A case-control study of nasopharyngeal carcinoma in the high background radiation areas of Yangjiang, China

    International Nuclear Information System (INIS)

    The main purposes of this study were to identify the major determinants of nasopharyngeal carcinoma (NPC) in the high-background radiation areas (HBRA) in Yangjiang, China and to evaluate their potential confounding effects on the NPC risk associated with exposure to high background radiation. A matched case-control study was conducted using those who died of NPC during the period 1987-1995. Two controls were randomly selected for each case from those who died from causes other than malignancies and external causes. Cases and their controls were matched with respect to sex and the years of birth and death (±5 years). Study subjects' next-of-kin were interviewed using a standardized questionnaire to collect information on socioeconomic status, dietary habits, tobacco smoking and alcohol consumption, disease history, pesticide use, medical X-ray exposure, the family history of NPC and so on. We succeeded in interviewing 97 cases and 192 controls. Univariate conditional logistic regression analysis showed that NPC risk was associated with the consumption of salted fish, homemade pickles, and fermented soy beans, education levels, the history of chronic rhinitis, and the family history of NPC. Multivariate conditional logistic regression analysis revealed that education levels (Odds ratio (OR) for middle school or higher levels vs. no school education=3.8, 95% CI=1.2 to 11.8), salted fish intake (OR=3.2, 95% CI=1.7 to 6.1), the history of chronic rhinitis (OR=3.6, 95% CI=1.3 to 10.1), and the family history of NPC (OR=14.2, 95% CI=2.7 to 73.4) were independent risk factors of NPC. Tobacco smoking (OR=1.2, 95% CI=0.7 to 2.1), and alcohol consumption (OR=0.9, 95% CI=0.5 to 1.9) were not significantly related to NPC risk. The ORs of NPC risk comparing HBRA and a nearby control area before and after adjustment for the major risk determinants identified in the present study were 0.86 (95% CI=0.50 to 1.50) and 0.87 (95% CI=0.45 to 1.67), respectively. Salted fish intake was

  12. Radiative Transfer in a Clumpy Universe. IV. New Synthesis Models of the Cosmic UV/X-Ray Background

    Science.gov (United States)

    Haardt, Francesco; Madau, Piero

    2012-02-01

    We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. Five new main components are added to our radiative transfer code CUBA: (1) the sawtooth modulation of the background intensity from resonant line absorption in the Lyman series of cosmic hydrogen and helium; (2) the X-ray emission from the obscured and unobscured quasars that gives origin to the X-ray background; (3) a piecewise parameterization of the distribution in redshift and column density of intergalactic absorbers that fits recent measurements of the mean free path of 1 ryd photons; (4) an accurate treatment of the photoionization structure of absorbers, which enters in the calculation of the helium continuum opacity and recombination emissivity; and (5) the UV emission from star-forming galaxies at all redshifts. We provide tables of the predicted H I and He II photoionization and photoheating rates for use, e.g., in cosmological hydrodynamics simulations of the Lyα forest and a new metallicity-dependent calibration to the UV luminosity density-star formation rate density relation. A "minimal cosmic reionization model" is also presented in which the galaxy UV emissivity traces recent determinations of the cosmic history of star formation, the luminosity-weighted escape fraction of hydrogen-ionizing radiation increases rapidly with look-back time, the clumping factor of the high-redshift intergalactic medium evolves following the results of hydrodynamic simulations, and Population III stars and miniquasars make a negligible contribution to the metagalactic flux. The model provides a good fit to the hydrogen-ionization rates inferred from flux decrement and proximity effect measurements, predicts that cosmological H II (He III) regions overlap at redshift 6.7 (2.8), and yields an optical depth to Thomson scattering, τes = 0.084 that is in agreement with Wilkinson Microwave Anisotropy Probe results. Our new

  13. Estimation of thorium intake due to consumption of vegetables by inhabitants of high background radiation area by INAA

    International Nuclear Information System (INIS)

    A study was conducted to estimate the thorium concentration in locally grown vegetables in high background radiation area (HBRA) of southern coastal regions of India. Locally grown vegetables were collected from HBRA of southern coastal regions of India. Thorium concentration was quantified using instrumental neutron activation analysis. The samples were irradiated at CIRUS reactor and counted using a 40% relative efficiency HPGe detector coupled to MCA. The annual intake of thorium was evaluated using the consumption data provided by National Nutrition Monitoring Board. The daily intake of 232Th from the four food categories (green leafy vegetables, others vegetables, roots and tubers, and fruits) ranged between 0.27 and 5.352 mBq d-1. The annual internal dose due to ingestion of thorium from these food categories was 46.8 x 10-8 for female and 58.6 x 10-8 Sv y-1 for male. (author)

  14. Mapping of thoron emission from monazite bearing beach sands at high background radiation areas of Kerala and Orissa

    International Nuclear Information System (INIS)

    Inhalation of radon, thoron and their short-lived daughter products contribute the largest fraction of radiation dose from natural sources. Though considerable attention has been give to radon, thoron and its daughters have been neglected owing to its very short half-life (55.6 sec). However study of thoron and its decay products becomes important in regions like High Background Radiation Areas (HBRA). In fact, they may be expected to contribute a major fraction of inhalation dose to the public residing in the HBRA, due to significant thoron exhalation from monazite beach sands. Hence mapping of thoron emission from monazite beach sand is important to identify areas with high thoron source potential and to investigate the dosimetric issues in these regions in a more effective manner. The thoron fluxes measured at beaches in Kerala were in the range of BDL to 18 Bqm-2s-1 with an average of 8 ± 4 Bq. m-2s-1. While, the thoron fluxes at the beaches in Orissa were in the range of BDL to 12 Bq.m-2 with an average value of 7 ± 3 Bq.m-2s-1. The average flux in this region is about 10 times higher than that of normal regions. An important feature that was noticed was that the variation of thoron flux for a particular beach is not significantly large indicating thoron flux is a stable index parameter unlike the atmospheric thoron concentration which varies considerably within few centimeter distance

  15. An introductory overview of the epidemiological study on the population at the high background radiation areas in Yangjiang, China

    Energy Technology Data Exchange (ETDEWEB)

    Wei Luxin [Ministry of Health, Beijing (China). Lab. of Industrial Hygiene; Sugahara, Tsutomu

    2000-10-01

    The epidemiological study on the residents of the high background radiation areas in Yangjiang, China was started by Chinese scientists in 1972 and continued until 1986. In 1991, Japanese scientists recognized the importance of the work and a joint feasibility study was conducted with revised protocols. The feasibility study matured to a cooperative project involving both Chinese and Japanese scientists in 1992, which currently is still in progress. The project was divide into three phases; the first being from 1992 to 1995, the second from 1995-1998 and the third from 1998 to 2001. The results of the first phase were reported previously in 1996. The present paper is a historical overview of the studies before the cooperation and the first two phases. Remarks are made on the detailed data on dosimetry, cytogenetic studies and cancer epidemiology of a series of the papers in this supplemental issue. Some problems such as paradoxical observations between cytogenetic results and cancer mortality, and the importance of the high background study in risk assessment are discussed. (author)

  16. Radiative transfer in a clumpy universe: IV. New synthesis models of the cosmic UV/X-ray background

    CERN Document Server

    Haardt, Francesco

    2011-01-01

    We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. Five new main components are added to our radiative transfer code CUBA: (1) the sawtooth modulation of the background intensity from resonant line absorption in the Lyman series of cosmic hydrogen and helium; (2) the X-ray emission from obscured and unobscured quasars; (3) a piecewise parameterization of the distribution in redshift and column density of intergalactic absorbers that fits recent measurements of the mean free path of 1 ryd photons; (4) an accurate treatment of the photoionization structure of absorbers; and (5) the UV emission from star-forming galaxies at all redshifts. We provide tables of the predicted HI and HeII photoionization and photoheating rates for use, e.g., in cosmological hydrodynamics simulations of the Lya forest, and a new metallicity-dependent calibration to the UV luminosity density-star formation rate density relation. A "minimal cosm...

  17. Th-230/Th-232 sedimentation rates and the natural radiation background along the western coast of Israel

    International Nuclear Information System (INIS)

    The natural radiation background of the sediments from the southeastern province of the Levant Basin was determined by both alpha-particle spectrometry and by gamma-ray spectrometry using a specially low background high resolution Ge(Li) detector. The Nile river derived clastics dominates the sediment character along the Israeli coast. The radioelements in nine cores under the Nile's influence are readily distinguishable, having higher potassium, uranium and thorium contents, from the more carbonate rich sediments investigated in three cores from the northwestern province of the Levant Basin. Significant fluctuations exist in the radiometal content with depth within individual cores. The rate of sediment transport and deposition are so rapid that no Th-230 excess accumulated in the sediment deposited relatively nearshore. In the deep water of the Herodotus Basin only a small degree of Th-230 excess is recorded. Determination of absolute rates of sedimentation by uranium series disequilibria is not feasible for the sediments near to the Israeli coast, while such studies in the Herodotus Basin would require long core lengths to succeed

  18. Assessment of radiation background level of Shandong basin in east line of northward rerouting of southern river

    International Nuclear Information System (INIS)

    Objective: To assess the radiation background levels of Shandong basin in east line of northward rerouting of southern river. Methods: The activity concentrations of gross-alpha, gross-beta, 137Cs, 238U, 232Th, 40K, 226Ra and 90Sr in the samples were measured by national standard methods respectively. The values of the dose conversion factor given by UNSCEAR 2000 were adopted for dose estimation. Results: The average activity concentrations of gross-alpha, gross-beta, 137Cs, 238U, 232Th, 40K, 226Ra and 90Sr in the samples were pooled in order to analyze dose estimation. The committed effective doses of the 226Ra, 238U, 90Sr, 232Th and 137Cs from lake water for residents are 1.46, 4.95 x 10-1, 1.24 x 10-1, 2.58 x 10-2 and 7.93 x 10-3 μSv per year respectively. The committed effective doses of the 226Ra, 238U and 90Sr from cyprinoid fish are 5.49 x 10-2, 3.69 x 10-2 and 1.77 x 10-2 μSv per year respectively. Conclusions: The results show that the average activity concentrations of gross-alpha, gross-beta, 137Cs, 238U, 232Th, 40K, 226Ra and 90Sr in the samples from Shandong basin of northward rerouting of southern river are within the background levels. And in the main lake basin, the estimated exposures of public caused by the radionuclide in water and cyprinoid fish are so low that they can be ignored unless there ate some radioactive contamination in the future. (authors)

  19. Sparsely Ionizing Diagnostic and Natural Background Radiations are Likely Preventing Cancer and Other Genomic-Instability-Associated Diseases

    OpenAIRE

    Scott, Bobby R.; Di Palma, Jennifer

    2006-01-01

    Routine diagnostic X-rays (e.g., chest X-rays, mammograms, computed tomography scans) and routine diagnostic nuclear medicine procedures using sparsely ionizing radiation forms (e.g., beta and gamma radiations) stimulate the removal of precancerous neo-plastically transformed and other genomically unstable cells from the body (medical radiation hormesis). The indicated radiation hormesis arises because radiation doses above an individual-specific stochastic threshold activate a system of coop...

  20. Establishment of immortalized B lymphoblastoid cell lines of old residents in high background radiation area in Guangdong, China

    International Nuclear Information System (INIS)

    Objective: To establish the immortalized cell lines of peripheral blood lymphocytes for old male residents in high background radiation area (HBRA) in Guangdong, China, in order to preserve the specific genomic resources of residents in HBRA for the further genetic and molecular biological study on HBRA. Methods: The peripheral blood samples of 20 old male residents in HBRA were collected after informed consent. The immortalized B lymphoblastoid cell lines, 2 fox each resident, were established with Epstein-Barr virus. After being frozen and recovered, the cell viability, the contamination of bacterium and mycoplasma were analyzed. The stabilization of cell lines was decided by comparing the karyotypes of the peripheral blood lymphocytes and the cell lines. Results: 40 cell lines for 20 residents in HBRA were successfully established.. The recovery rate of cell lines after being frozen was 100% . All the cell viablity after recovery was higher than 90%, and no contamination of bacteria and mycoplasma occurred. The karyotypes of the 20th generation cell lines were not change. Conclusion: The immortalized cell lines established in this study could provide biological resources for further study on genetics and molecular biology in HBRA. (authors)

  1. A Bridge from Optical to Infrared Galaxies Explaining Local Properties, Predicting Galaxy Counts and the Cosmic Background Radiation

    CERN Document Server

    Totani, T; Totani, Tomonori; Takeuchi, Tsutomu T.

    2002-01-01

    We give an explanation for the origin of various properties observed in local infrared galaxies, and make predictions for galaxy counts and cosmic background radiation (CBR), by a new model extended from that for optical/near-infrared galaxies. Important new characteristics of this study are that (1) mass scale dependence of dust extinction is introduced based on the size-luminosity relation of optical galaxies, and that (2) the big grain dust temperature T_dust is calculated based on a physical consideration for energy balance, rather than using the empirical relation between T_dust and total infrared luminosity L_IR found in local galaxies, which has been employed in most of previous works. Consequently, the local properties of infrared galaxies, i.e., optical/infrared luminosity ratios, L_IR-T_dust correlation, and infrared luminosity function are outputs predicted by the model. Our model indeed reproduces these local properties reasonably well. We then found considerably different results for MIR-submm co...

  2. Radiation-induced Backgrounds in Astronomical Instruments: Considerations for Geosynchronous Orbit and Implications for the Design of the WFIRST Wide-field Instrument

    Science.gov (United States)

    Kruk, Jeffrey W.; Xapsos, Michael A.; Armani, Nerses; Stauffer, Craig; Hirata, Christopher M.

    2016-03-01

    Geosynchronous orbits are appealing for solar or astrophysical observatories because they permit continuous data downlink at high rates. The radiation environment in these orbits presents unique challenges, however. This paper describes both the characteristics of the radiation environment in geosynchronous orbit and the mechanisms by which this radiation generates backgrounds in photon detectors. Shielding considerations are described, and a preliminary shielding design for the proposed Wide-Field InfraRed Survey Telescope observatory is presented as a reference for future space telescope concept studies that consider a geosynchronous orbit.

  3. Study of natural background radiation levels with special reference to the granite industries and quarries in some places of Karnataka State

    International Nuclear Information System (INIS)

    Radiation is present all around us which may be also called natural background radiation. It is divided into natural and anthropogenic. The sources of natural radiation are extra terrestrial (cosmic ray) radiation and terrestrial radiation; it arises due to naturally occurring radionuclides present in soil, rocks and building materials. Whereas anthropogenic radiation sources includes X rays used for medical diagnosis nuclear weapon testing nuclear power plants radioisotopes used in varies fields, other industry applications and scientific research. Out of the total radiation exposure nearly 97.7% is from natural sources and remaining 2.3% is due to artificial sources. Nature has gifted several geological material to mankind for building purposes. The granite rocks are used as building material, these rocks are quite rich in radioactive nuclides. The radiation from these nuclides are exposed to mankind and the rocks are exploited and extracted by miners to construct the buildings. Natural radiation is of importance because it accounts for the largest contributor of radiation exposure to the world population from all natural sources (UNSCEAR 2008). Understanding the magnitude of natural sources of radiation and their distribution in the living environment may help any one to develop a pragmatic approach towards radiation and its effects. This article provides a radiation levels measured in granite quarries and industries and assessment of health effects to the workers and publics of the study area. The total occupational dose to the workers is lower than ICRP recommended value and the total dose for the public is slightly higher than the global average value. There is no regulation control for the granite mining. As per the IAEA report regulatory control is needed for mining and processing of granite rocks The study area is granite region of Bangaluru rural district, Tumkur and Mysore. (author)

  4. Updated estimates of the proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionising radiation

    International Nuclear Information System (INIS)

    The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionising radiation, such as was experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily upon studies of the Japanese A-bomb survivors imply that low-level exposure to ionising radiation, including to ubiquitous natural background radiation, also raises the risk of childhood leukaemia. In a recent paper (Wakeford et al 2009 Leukaemia 23 770-6) we estimated the proportion of childhood leukaemia incidence in Great Britain attributable to natural background radiation to be about 20%. In this paper we employ the two sets of published leukaemia risk models used previously, but use recently published revised estimates of natural background radiation doses received by the red bone marrow of British children to update the previous results. Using the newer dosimetry we calculate that the best estimate of the proportion of cases of childhood leukaemia in Great Britain predicted to be attributable to this source of exposure is 15-20%, although the uncertainty associated with certain stages in the calculation (e.g. the nature of the transfer of risk between populations and the pertinent dose received from naturally occurring alpha-particle-emitting radionuclides) is significant. The slightly lower attributable proportions compared with those previously derived by Wakeford et al (Leukaemia 2009 23 770-6) are largely due to the lower doses (and in particular lower high LET doses) for the first year of life.

  5. Updated estimates of the proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionising radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, Mark P [Department of Epidemiology and Public Health, Imperial College, London W2 1PG (United Kingdom); Wakeford, Richard [Dalton Nuclear Institute, University of Manchester, Pariser Building-G Floor, PO Box 88, Sackville Street, Manchester M60 1QD (United Kingdom); Kendall, Gerald M [Childhood Cancer Research Group, Richards Building, University of Oxford, Old Road Campus, Oxford OX3 7LG (United Kingdom)], E-mail: mark.little@imperial.ac.uk

    2009-12-01

    The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionising radiation, such as was experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily upon studies of the Japanese A-bomb survivors imply that low-level exposure to ionising radiation, including to ubiquitous natural background radiation, also raises the risk of childhood leukaemia. In a recent paper (Wakeford et al 2009 Leukaemia 23 770-6) we estimated the proportion of childhood leukaemia incidence in Great Britain attributable to natural background radiation to be about 20%. In this paper we employ the two sets of published leukaemia risk models used previously, but use recently published revised estimates of natural background radiation doses received by the red bone marrow of British children to update the previous results. Using the newer dosimetry we calculate that the best estimate of the proportion of cases of childhood leukaemia in Great Britain predicted to be attributable to this source of exposure is 15-20%, although the uncertainty associated with certain stages in the calculation (e.g. the nature of the transfer of risk between populations and the pertinent dose received from naturally occurring alpha-particle-emitting radionuclides) is significant. The slightly lower attributable proportions compared with those previously derived by Wakeford et al (Leukaemia 2009 23 770-6) are largely due to the lower doses (and in particular lower high LET doses) for the first year of life.

  6. Spatial and depth wise characterization of radionuclides and minerals in various beach sediments from high background radiation area, Kerala, India

    International Nuclear Information System (INIS)

    The activity concentrations (238U, 232Th and 40K) and mineralogical characterization of different layer (upper surface, first, second and third feet) Kerala beach sediments have been assessed with an aim of evaluating the radioactivity content profile, its relation to specific minerals and their distributions (spatial and depth wise). The eight different radiological indices are calculated for all samples and compared with either recommended values or the world average values of radioactivity content of the three primordial radionuclides to assess the complete radiological profile of the sediments. The radioactivity study suggests that the average specific activities of radionuclides (238U and 232Th) are higher than the world average values as given in UNSCEAR reports and all radiological parameters in all layer samples are more than the recommended safety levels. These results are on the expected lines since the samples are from a well-known high background radiation area. Using FTIR, mineralogical characteristics of the sediments were analyzed and the extinction coefficient is calculated to find the relative distribution of major minerals. The calculated values show that the amount of major minerals decreases in the order of quartz>calcite>kaolinite>microcline feldspar in all layers. To confirm the results obtained from FTIR, XRD analysis was also carried out. The observations made through the XRD technique are matched with FTIR observations. Statistical analyses (cluster and factor analysis) are carried out to assess the relation between the radionuclides and minerals, and also assess their distribution patterns in different layers. The analyses suggest that the concentration of 40K may have a strong association with the light mineral calcite and also suggest that spatial distributions of 40K and calcite are almost similar in every layer. The concentrations of 238U, 232Th and absorbed dose rate are evenly distributed (spatial) and other variables are randomly

  7. The assessment of cytotoxic T cell and natural killer cells activity in residents of high and ordinary background radiation areas of Ramsar-Iran

    Directory of Open Access Journals (Sweden)

    Sajad Borzoueisileh

    2013-01-01

    Full Text Available The effective radiation dose of human from natural sources is about 2.4 mSv/y and the dose limit for radiation workers is 20 mSv/y. Ramsar, a city in Iran, has been the subject of concern in the last forty years for a high level of radiation measured in some spots as high as 260 mSv/y. Carcinogenesis is one of the most studied effects of radiation especially in high doses. Recent studies showed that the high level of natural radiation received by inhabitants of this area, paradoxically don′t have significant health effect. Natural killer (NK cells and cytotoxic T cells are the most important cells in tumor immune surveillance and CD107a is a widely expressed intracellular protein located in the lysosomal/endosomal membrane. CD107a transiently located on the cell membrane can be used as a marker of CD8 + T cell degranulation following stimulation. It is also expressed, to a lower extent, on activated NK cells. In this study, 60 healthy people were selected randomly and their consent obtained and confounding factors such as sex, age, life-styles was matched then the count of activated NK and CD8 + cells was compared in high and normal background radiation areas inhabitants of Ramsar. After filling the questionnaire and measurement of background radiation, blood samples of 30 healthy people from each region were analyzed immediately by means of flowcytometry. The leukocytes and their subsets were not significantly different between two groups and the count of active cells was higher in control group. The result shows that the changes in immune system occur due to radiation and maybe it is as a result of higher radiosensitivity of activated cells.

  8. The assessment of cytotoxic T cell and natural killer cells activity in residents of high and ordinary background radiation areas of Ramsar-Iran

    International Nuclear Information System (INIS)

    The effective radiation dose of human from natural sources is about 2.4 mSv/y and the dose limit for radiation workers is 20 mSv/y. Ramsar, a city in Iran, has been the subject of concern in the last forty years for a high level of radiation measured in some spots as high as 260 mSv/y. Carcinogenesis is one of the most studied effects of radiation especially in high doses. Recent studies showed that the high level of natural radiation received by inhabitants of this area, paradoxically don't have significant health effect. Natural killer (NK) cells and cytotoxic T cells are the most important cells in tumor immune surveillance and CD107a is a widely expressed intracellular protein located in the lysosomal/endosomal membrane. CD107a transiently located on the cell membrane can be used as a marker of CD8 + T cell degranulation following stimulation. It is also expressed, to a lower extent, on activated NK cells. In this study, 60 healthy people were selected randomly and their consent obtained and confounding factors such as sex, age, life-styles was matched then the count of activated NK and CD8 + cells was compared in high and normal background radiation areas inhabitants of Ramsar. After filling the questionnaire and measurement of background radiation, blood samples of 30 healthy people from each region were analyzed immediately by means of flowcytometry. The leukocytes and their subsets were not significantly different between two groups and the count of active cells was higher in control group. The result shows that the changes in immune system occur due to radiation and maybe it is as a result of higher radiosensitivity of activated cells. (author)

  9. Assessment of a relative contribution of terrestrial background radiation in the test field by using RADIAGEMTM 2000 portable survey meter

    Directory of Open Access Journals (Sweden)

    Avdić Senada

    2016-01-01

    Full Text Available This study is focused on the radiological investigation of terrestrial gamma radiation in the test field with soil samples from different minefields in the Federation of Bosnia and Herzegovina. Measurements of ambient dose equivalent rate, commonly referred to as “air dose rate”, in the test field located in the Tuzla Canton, were performed by RADIAGEMTM 2000 portable survey meter, based on energy-compensated Geiger-Muller counter. Its performances were tested in the laboratory conditions with gamma point sources. Since all the samples in the test field were exposed to the same cosmic radiation, there was a possibility to assess a relative contribution of terrestrial gamma radiation due to soil samples of different composition. One set of measurements in the test field was performed with RADIAGEMTM 2000, at a height of about one meter above the ground and basic statistical parameters indicated that there was no significant difference of terrestrial gamma radiation from different soil samples. The other set of measurements was carried out with the same device placed on the ground in the test field. Processing of experimental data on terrestrial gamma radiation has shown that it was possible to make a difference between relative contributions of terrestrial gamma radiation from individual soil samples. The results of investigation could be useful for multiple purposes of public interest.

  10. Dependence of regular background noise of VLF radiation and thunder-storm activity on solar wind proton density

    International Nuclear Information System (INIS)

    Correlation of the intensity of slowly changing regular background noise within 9.7 kHz frequency in Yakutsk (L = 3) and of the solar wind density protons was determined. This result explains the reverse dependence of the intensity of the regular background noise on the solar activity, 27-day frequency, increase before and following geomagnetic storms, absence of relation with Kp index of geomagnetic activity. Conclusion is made that growth of density of the solar wind protons results in increase of the regular background noise and thunderstorm activity

  11. Childhood exposures to Rn-222 and background gamma radiation in the uranium provinces of south Kazakhstan and northern Kyrgyzstan

    International Nuclear Information System (INIS)

    The project was undertaken in southern Kazakhstan and Kyrgyzstan. It was speculated that the radiation doses in these areas would be sufficiently high and dispersed to facilitate a case–control study where the radiation doses to leukaemia subjects/their siblings could be compared with those received by control children. As a precursor a pilot project was undertaken to confirm radiation exposures in the region. This was undertaken in association with regional childhood cancer treatment centres. Children from families affected by childhood leukaemia were monitored for 1 month for external γ-radiation dose and for exposure to radon gas. 28 children from families in Kazakhstan and from 31 families in Kyrgyzstan were monitored. The median measured radon in air concentration recorded in Kazakhstan was 123 Bq m−3 and in Kyrgyzstan was 177 Bq m−3. These represent 24-h average indoor/outdoor values. In the case of the γ-doses the mean annual dose was 1.2 mGy for Kazakhstan and 2.1 mGy for Kyrgyzstan. Overall, the results suggest that the populations studied receive similar annual radiation doses to those received by populations living in other areas with enhanced natural radioactivity and that further study of Kazakh and Kyrgyz populations would not facilitate a successful case–control study for childhood leukaemia

  12. e+e- -> pi+pi-e+e-: a potential background for sigma(e+e- -> pi+pi-) measurement via radiative return method

    OpenAIRE

    Czyz, Henryk; Nowak, Elzbieta

    2003-01-01

    A Monte Carlo generator (EKHARA) has been constructed to simulate the reaction e+e- -> pi+pi-e+e- based on initial and final state emission of a e+e- pair from e+e- -> pi+pi- production diagram.A detailed study of the process, as a potential background for sigma(e+e- -> pi+pi-) measurement via radiative return method, is presented for phi- and B- factory energies.

  13. Can radiative cooling and nongravitational heating explain simultaneously the global X-ray properties of clusters and the unresolved cosmic X-ray background ?

    OpenAIRE

    Xue, Yan-Jie; Wu, Xiang-Ping

    2002-01-01

    Using a simple analytic approach we address the question of whether radiative cooling, nongravitational heating and cooling plus heating models can simultaneously explain the observed global X-ray properties (entropy and X-ray luminosity distributions) of groups and clusters and the residual soft X-ray background (XRB) after discrete sources are removed. Within the framework of typical cold dark matter structure formation characterized by an amplitude of matter power spectrum sigma_8=0.9, it ...

  14. Evaluation of DNA damage in the root cells of Allium cepa seeds growing in soil of high background radiation areas of Ramsar - Iran

    Energy Technology Data Exchange (ETDEWEB)

    Saghirzadeh, M. [Department of Basic Science, Gonabad University of Medical Sciences, Gonabad (Iran, Islamic Republic of); Gharaati, M.R. [Faculty of Science, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Mohammadi, Sh. [Nuclear Science and Technology Research Institute (NSTRI), Radiation Applications Research School, Tehran 11365-3486 (Iran, Islamic Republic of)], E-mail: smohammadi@aeoi.org.ir; Ghiassi-Nejad, M. [Faculty of Science, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2008-10-15

    Plants are unique in their ability to serve as in situ monitors for environmental genotoxins. We have used the alkaline comet assay for detecting induced DNA damage in Allium cepa to estimate the impact of high levels of natural radiation in the soils of inhabited zones of Ramsar. The average specific activity of natural radionuclides measured in the soil samples for {sup 226}Ra was 12,766 Bq kg{sup -1} whereas in the control soils was in the range of 34-60 Bq kg{sup -1}. A positive strong significant correlation of the DNA damage in nuclei of the root cells of A. cepa seeds germinated in the soil of high background radiation areas with {sup 226}Ra specific activity of the soil samples was observed. The results showed high genotoxicity of radioactively contaminated soils. Also the linear increase in the DNA damage indicates that activation of repair enzymes is not triggered by exposure to radiation in HBRA.

  15. Influence factors of risk perception of radiation and its background. Questionnaire survey for reclamation project in the uranium mine

    International Nuclear Information System (INIS)

    To obtain public understanding on the uranium mining sites reclamation at Ningyo-toge Environmental Engineering Center, it is necessary to conduct appropriate Risk Communication (RC). In this study, to discuss the appropriate Risk communication method on the uranium mining sites reclamation, we conducted questionnaire survey and text analysis. The results of the text analysis are as follows: (1) The main elements of the concern of radiation are the uneasiness to oncogenesis or a health effect. (2) The trusts for technology or scientists are the main elements of the reliance for the standard of radiation, in the group which shows low-sense of ownership, hatred for radioactive ray has a strong impact relatively. (author)

  16. Assessment of radon concentration and external gamma radiation level around a high background radiation area (HBRA), Odisha, India and its radiological significance

    International Nuclear Information System (INIS)

    Present study gives a brief account of the atmospheric radon concentration, gamma absorbed dose rate and radiation dose received by the members of public residing in a coastal HBRA, Chatrapur, Odisha, India. The external gamma radiation dose varies from 40 to 1800 nSv/h, averaged by 226 nSv/h. The total average effective dose rate received by members of public from inhalation of radon and its progeny and external gamma exposure was estimated to be 4 ± 1.0 mSv/y, ranged between 2.4 and 6.3 mSv/y, which is nearly two higher than the global average value of effective dose to public due to natural radiation exposure. (author)

  17. Inhalation exposures due to radon and thoron ((222)Rn and (220)Rn): Do they differ in high and normal background radiation areas in India?

    Science.gov (United States)

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

    2015-09-01

    In India, High Background Radiation Areas (HBRAs) due to enhanced levels of naturally occurring radionuclides in soil (thorium and, to a lesser extent, uranium), are located along some parts of the coastal tracts viz. the coastal belt of Kerala, Tamilnadu and Odisha. It is conjectured that these deposits will result in higher emissions of radon isotopes ((222)Rn and (220)Rn) and their daughter products as compared to Normal Background Radiation Areas (NBRAs). While the annual external dose rates contributed by gamma radiations in these areas are about 5-10 times higher, the extent of increase in the inhalation dose rates attributable to (222)Rn and (220)Rn and their decay products is not well quantified. Towards this, systematic indoor surveys were conducted wherein simultaneous measurements of time integrated (222)Rn and (220)Rn gas and their decay product concentrations was carried out in around 800 houses in the HBRAs of Kerala and Odisha to estimate the inhalation doses. All gas measurements were carried out using pin-hole cup dosimeters while the progeny measurements were with samplers and systems based on the Direct radon/thoron Progeny sensors (DRPS/DTPS). To corroborate these passive measurements of decay products concentrations, active sampling was also carried out in a few houses. The results of the surveys provide a strong evidence to conclude that the inhalation doses due to (222)Rn and (220)Rn gas and their decay products in these HBRAs are in the same range as observed in the NBRAs in India. PMID:26065929

  18. Discovery of the Galaxy Proximity Effect and Implications for Measurements of the Ionizing Background Radiation at Low Redshifts

    CERN Document Server

    Pascarelle, S M; Chen, H W; Webb, J K; Pascarelle, Sebastian M.; Lanzetta, Kenneth M.; Chen, Hsiao-Wen; Webb, John K.

    2001-01-01

    We present an analysis of galaxy and QSO absorption line pairs toward 24 QSOs at redshifts between z~0.2 and 1 in an effort to establish the relationship between galaxies and absorption lines in physical proximity to QSOs. We demonstrate the existence of a galaxy proximity effect, in that galaxies in the vicinities of QSOs do not show the same incidence and extent of gaseous envelopes as galaxies far from QSOs. We show that the galaxy proximity effect exists to galaxy-QSO velocity separations of ~ 3000 km/s, much larger than the size of a typical cluster (~ 1000 km/s), i.e. it is more comparable to the scale of the sphere of influence of QSO ionizing radiation rather than the scale of galaxy-QSO clustering. This indicates that the QSO ionizing radiation rather than some dynamical effect from the cluster environment is responsible for the galaxy proximity effect. We combine previous findings that (1) many or most Lya absorption lines arise in extended galaxy envelopes, and (2) galaxies cluster around QSOs to s...

  19. Radiocarbon dating of archaeological samples (sambaqui) using CO2 absorption and liquid scintillation spectrometry of low background radiation

    International Nuclear Information System (INIS)

    Sambaqui means, in the Tupi language, a hill of shells. The sambaquis are archaeological sites with remains of pre-historical Brazilian occupation. Since the sambaqui sites in the Rio de Janeiro state region are older than 10,000 years, the applicability of CO2 absorption on Carbo-sorb[reg] and 14C determination by counting on a low background liquid scintillation counter was tested. In the present work, sambaqui shells were treated with H3PO4 in a closed vessel in order to generate CO2. The produced CO2 was absorbed on Carbo-sorb[reg]. On saturation about 0.6 g of carbon, as CO2, was mixed with commercial liquid scintillation cocktail (Permafluor[reg]), and the 14C activity determined by counting on a low background counter, Packard Tricarb 3170 TR/SL, for a period of 1000 mins to enable detection of a radiocarbon age of 22,400 BP. But only samples with ages up to 3500 BP were submitted to the method because the samples had been collected in the municipality of Guapimirim, in archaeological sambaqui-type sites belonging to this age range. The same samples were sent to the 14C Laboratory of the Centro de Energia Nuclear na Agricultura (CENA/USP) where similar results were obtained

  20. Epidemiology of non-syndromic cleft lip/palate in the high level natural background radiation areas (HLNRA) of the South west coast of India

    International Nuclear Information System (INIS)

    All consecutive births in selected government hospitals in and around the high level natural background radiation areas (HLNRA) of Kerala were monitored for congenital malformations observable at birth since 1995. The HLNR area, with natural deposits of monazite sand containing thorium (8-10%) and Uranium (0.3%), is a coastal strip of land about 55 km in length and 0.5 km in breadth from Purakkad in the north in Alleppey district to Sakthikulangara in the south of Quilon district and is one among the most prominent background radiation areas of the world. Patchy and non-uniform distribution of Monazite sand causes wide variation in dose ranging from <1 to 45 mGy/year. High population density, limited migration, ethnic diversity, good literacy, health awareness, institutionalized births and acceptance of small family norm are some of the key features of the population. Areas with a mean radiation dose of more than 1.5 mGy/year were treated as HLNR areas and areas with a dose level of 1.5 mGy/year or less were treated as normal level radiation areas (NLNRA). A total of 134,178 newborns were monitored and non-syndromic cleft lip/palate (NSCLP) was detected in 143 newborns (1.07%). Cleft lip with cleft palate (59.4%) was more common than cleft lip (18.2%) or Cleft palate (22.4%) alone and 11.9% had other malformation(s) together with NSCLP. There was no evidence to suggest that NSFC was significantly associated with prevailing dose level of area of mother's residence, maternal age birth, gravida, ethnicity or consanguinity

  1. The temperature of the cosmic microwave background radiation at 3.8 GHz - Results of a measurement from the South Pole site

    Science.gov (United States)

    De Amici, Giovanni; Limon, Michele; Smoot, George F.; Bersanelli, Marco; Kogut, AL; Levin, Steve

    1991-01-01

    As part of an international collaboration to measure the low-frequency spectrum of the cosmic microwave background (CMB) radiation, its temperature was measured at a frequency of 3.8 GHz, during the austral spring of 1989, obtaining a brightness temperature, T(CMB), of 2.64 +/-0.07 K (68 percent confidence level). The new result is in agreement with previous measurements at the same frequency obtained in 1986-88 from a very different site and has comparable error bars. Combining measurements from all years, T(CMB) = 2.64 +/-0.06 K is obtained.

  2. Measurement of thorium and uranium activity with rare earth elements in soil samples near Chhatrapur, Orissa, India a natural high background radiation area

    International Nuclear Information System (INIS)

    The main aim of this present study is to evaluate the level of thorium and uranium activity as well as rare earth elements in a natural high background radiation area (HBRA) near Chhatrapur of Orissa state in India. Soil samples collected from HBRA were analyzed by γ-ray spectrometry as well as inductively coupled plasma mass spectrometry (ICP-MS). The radioactivity is found to be mainly contributed from thorium. Concentration of thorium and TiO2 is reported to be very high compared to normal abundance in crystal rocks. A large variation in absorbed gamma dose in air was observed

  3. CP violation in the K0 - anti K0 system. Study of the background noise minimization by means of a transition radiation detector

    International Nuclear Information System (INIS)

    This work has been performed for the NA31 experiment at CERN whose goal is a high precision mesurement of the parameter ε'/ε reflecting direct CP-violation in the K0 - anti K0 system. This work is concerned with the calibration and the study of the performance of the transition radiation detector, TRD, added recently to the experiment. The TRD provides an important increase in the pion/electrons separation. This allows a significant reduction in the systematic uncertainty in the background subtraction of the KL0 to two charged pions decay mode which is dominated by semileptonics decays. A complete calibration of this detector has been performed. Energy pulseheight response for various detectors parameters are reviewed. After all corrections, electron rejection efficiency is shown. We analyse then, the semi-leptonic charged background

  4. Are the inhabitants of high background radiation areas of Ramsar more radioresistant? scope of the problem and the need for future studies

    International Nuclear Information System (INIS)

    Background/objective: Ramsar in northern Iran is among the world's well-known areas with highest levels of natural radiation. Annual exposure levels in areas with elevated levels of natural radiation in Ramsar are up to 260 mGy y-1 and average exposure rates are about 10 mGy y-1 for a population of about 2000 residents. Due to the local geological features, which include high levels of radium in rocks, soils, and groundwater, Ramsar residents are also exposed to high levels of alpha activity in the form of ingested radium and radium decay progeny as well as very high radon levels (over 1000 MBq m-3) in their dwellings. In some cases, the inhabitants of these areas receive doses much higher than the current ICRP-60 dose limit of 20 mSv y-1 set for radiation workers. The extraordinary levels of natural radiation in Ramsar prompted us to assess the radiation susceptibility of the residents. Material and methods: venous blood samples were taken from 7 healthy blood donors of both sexes who lived in some areas of Ramsar with highest levels of natural radiation(dose rates were up to 155μ Sv h-1) and 5 healthy persons from a nearby control area. Standard condition for cell cultivation, irradiation and analysis of chromosome aberrations was used. The cells were exposed to the challenge dose of 1.5 Gy of Co-60 gamma ray 48 hours after PHA stimulation. Using mean chromosomal aberration per cell, the expected numbers of aberrations were calculated. Results: Lymphocytes of Ramsar residents when subjected to 1.5 Gy of Gamma rays, showed fewer chromosome aberrations compared to residents in a nearby control area. These findings clearly show that high levels of natural radiation may induce radio adaptive response. Interestingly. Conclusion: this radio adaptation phenomenon was found in individuals who received doses as much as a few hundred times more than the inhabitants of a nearby control area. More research is needed to precisely clarify if it is possible to relax the

  5. Th, U, Ra and rare earth element distributions in farm animal tissues from an elevated natural radiation background environment

    International Nuclear Information System (INIS)

    A field study was conducted in an area of elevated natural background radioactivity (the Pocos de Caldas plateau, Brazil) to assess tissue concentrations and the comparative bioavailability of isotopic Th (IV), U (IV, VI), Ra (II) and light rare earth elements (REE), i.e. La (III) and Ce (III, IV) in adult steers, pigs and chickens. The assessment of comparative bioavailability was aided by normalizing tissue concentrations to local soil concentrations, i.e. by calculating soil-to-tissue concentration ratios (CRs). Mean CRs (for muscle/soil) in these animals were very similar for U, La and Th which, as a group, decreased among the farm animals sampled as (all x 10-4): chicken (1) ≥ steer (0.7) ≥ pig (0.4). For 226Ra, CRs in muscle decreased in the same order among animals although mean values were 3-5 times greater than those quoted. Much greater values and greater differences among the elements are noted for bone/soil CRs, which for all animals decreased as: Ra >> U > La=Th, indicating the order of elemental bioavailability (assuming bone to be the major retention compartment). Isotopic ratios in farm animal tissue are shown to resemble closely those in soils over which the animals forage, with few exceptions, indicating the importance of the soil component in the transfer of these elements to tissues. (author)

  6. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    Science.gov (United States)

    Sutter, John P.; Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-01

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  7. Dose-effect relationship in production of dicentrics and rings in blood lymphocytes of individuals living in high background radiation area

    International Nuclear Information System (INIS)

    Objective: To explore the dose-effect relationship in the production of chromosome aberrations by high background radiation by using statistically appropriate individual measurements. Methods: Chromosome analysis was performed in separated blood lymphocytes of 39 family members of different ages from either high background radiation area (HBRA) or control area (CA). Individual cumulative doses ranged from 23.9-261.3 and 5.2-29.8 mGy for HBRA and CA, respectively. A total of about 100,000 cells were scored and dicentric and ring chromosome (dic + Rc) aberrations recorded. Results: In the case of HBRA, individual chromosome aberration frequencies increased with age within each family. The increasing trend was in general not significantly different among families. The increase in individual aberration was closely correlated with age and cumulative dose. Age-and dose-effect relationship fit well the linear equation: Y = 0.0448X + 0.4913 (R2 = 0.7814) for age and Y 0.0156X + 0.5715 (R2 = 0.7061) for cumulative dose, respectively. In the case of CA, there was no significant difference in aberration yields among individuals of different ages, and the group mean aberration frequency was 1.24 +- 0.69 x 10-3. Conclusions: Dic and Rc can continuously accumulate over a lifetime chronic low dose exposures, and can serve as a reliable biological indicator. However, the ultimate sensitivity is about 50 mGy

  8. Role of light and heavy minerals on natural radioactivity level of high background radiation area, Kerala, India

    International Nuclear Information System (INIS)

    Natural radionuclides (238U, 232Th and 40K) concentrations and eight different radiological parameters have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation hazards. Activity concentrations (238U and 232Th) and all the radiological parameters in most of the sites have higher values than recommended values. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area. In order to know the light mineral characterization of the present sediments, mineralogical analysis has been carried out using Fourier transform infrared (FTIR) spectroscopic technique. The eight different minerals are identified and they are characterized. Among the various observed minerals, the minerals such as quartz, microcline feldspar, kaolinite and calcite are major minerals. The relative distribution of major minerals is determined by calculating extinction co-efficient and the values show that the amount of quartz is higher than calcite and much higher than microcline feldspar. Crystallinity index is calculated to know the crystalline nature of quartz present in the sediments. Heavy mineral separation analysis has been carried out to know the total heavy mineral (THM) percentage. This analysis revealed the presence of nine heavy minerals. The minerals such as monazite, zircon, magnetite and illmenite are predominant. Due to the rapid and extreme changes occur in highly dynamic environments of sandy beaches, quantities of major light and heavy minerals are widely varied from site to site. Granulometric analysis shows that the sand is major content. Multivariate statistical (Pearson correlation, cluster and factor) analysis has been carried out to know the effect of mineralogy on radionuclide concentrations. The present study concluded that heavy minerals induce the 238U and 232Th

  9. Assessment of spatial distribution and radiological hazardous nature of radionuclides in high background radiation area, Kerala, India

    International Nuclear Information System (INIS)

    The concentration and distribution of the natural radionuclides (238U, 232Th and 40K) have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation hazards. The ranges of activity concentrations of 238U, 232Th and 40K are BDL—1187±21.7 Bq/kg, BDL—5328±23.2 Bq/kg and BDL—693±31.2 Bq/kg respectively. Radiological parameters such as absorbed dose rate, annual effective dose equivalent, annual gonadal dose equivalent, radium equivalent, hazard index, gamma Index, activity utilization index and excess lifetime cancer risk are calculated to know the complete radiological hazardous nature. Concentration of radionuclides (238U and 232Th) and all the calculated radiological parameters are higher in site number S23 (Chavara beach) due to the presence of rich deposits of black sands. Average concentrations of radionuclides (238U and 232Th) and all calculated radiological parameters are higher than the recommended level. Both univariate and multivariate statistical analyses were applied effectively to assess the distribution of the radionuclides. Univariate statistical analysis shows that the confirmation of infrequent extreme deviations of all radioactive variables. Cluster analysis shows that light minerals play a role in cluster I sampling sites and heavy minerals may be played in sampling sites of other clusters. Calculated activity ratio confirmed the presence of light and heavy minerals in above mentioned sampling sites. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area. - Highlights: ► The concentration and distribution of the natural radionuclides have been analyzed for the Kerala beach sediments. ► Average concentrations of 238U and 232Th, and all calculated radiological parameters are higher than the recommended level. ► Univariate statistical

  10. Thermoluminescence comparison among Al2O3:C, LiF:Mg, Ti and LiF:Mg, Cu, P for natural radiation background measurement

    International Nuclear Information System (INIS)

    To select thermoluminescent dosimeters (TLDs) for low radiation research,thermoluminescence responses of Al2O3:C, LiF:Mg, Ti and LiF:Mg, Cu, P were measured under natural radiation background in Zhanjiang city, China. TL sensitivity of the three TLDs, in terms of the threshold dose, is sequenced as Al2O3:C(1-2 μGy), LiF:Mg, Cu, P(about 2 μGy), and LiF:Mg, Ti(>10 μGy). However, as the temperature of glow peak of Al2O3:C is not so high, its TL decays in a relatively long period,hence the non-linearity of the TL dose response curve of Al2O3:C, while temperatures of glow peaks of LiF:Mg, Ti and LiF:Mg, Cu, P are higher, hence their linear TL dose response. Therefore, LiF:Mg, Cu, P is the best TLD for low radiation cumulative dose detection. (authors)

  11. Inhalation exposures due to radon and thoron (222Rn and 220Rn): Do they differ in high and normal background radiation areas in India?

    International Nuclear Information System (INIS)

    In India, High Background Radiation Areas (HBRAs) due to enhanced levels of naturally occurring radionuclides in soil (thorium and, to a lesser extent, uranium), are located along some parts of the coastal tracts viz. the coastal belt of Kerala, Tamilnadu and Odisha. It is conjectured that these deposits will result in higher emissions of radon isotopes (222Rn and 220Rn) and their daughter products as compared to Normal Background Radiation Areas (NBRAs). While the annual external dose rates contributed by gamma radiations in these areas are about 5–10 times higher, the extent of increase in the inhalation dose rates attributable to 222Rn and 220Rn and their decay products is not well quantified. Towards this, systematic indoor surveys were conducted wherein simultaneous measurements of time integrated 222Rn and 220Rn gas and their decay product concentrations was carried out in around 800 houses in the HBRAs of Kerala and Odisha to estimate the inhalation doses. All gas measurements were carried out using pin-hole cup dosimeters while the progeny measurements were with samplers and systems based on the Direct radon/thoron Progeny sensors (DRPS/DTPS). To corroborate these passive measurements of decay products concentrations, active sampling was also carried out in a few houses. The results of the surveys provide a strong evidence to conclude that the inhalation doses due to 222Rn and 220Rn gas and their decay products in these HBRAs are in the same range as observed in the NBRAs in India. - Highlights: • Measurements of 222Rn, 220Rn and their progeny in indoors of HBRAs of India. • DTPS/DRPS deposition sensors were used for measurement progeny of 222Rn and 220Rn. • Inhalation doses were in HBRAs were comparable with those in NBRAs

  12. Recent radiation of Brachystelma and Ceropegia (Apocynaceae) across the Old World against a background of climatic change.

    Science.gov (United States)

    Bruyns, P V; Klak, C; Hanáček, P

    2015-09-01

    The genera Brachystelma Sims and Ceropegia L. of the Ceropegieae (Apocynaceae-Asclepiadoideae) consist of ±320 species of geophytes and slender climbers with a tendency to stem-succulence in Ceropegia. They occur in and around the semi-arid, mainly tropical parts of the Old World. For 146 species (around half of the total) from most of the geographic range of the genera, we analysed data from two nuclear and five plastid regions. The evolution of Ceropegia is very complex, with at least 13 mostly well-supported lineages, one of which is sister to the ±350 species of stapeliads. Species of Brachystelma have evolved at least four times, with most of them nested within two separate major lineages. So, neither Brachystelma nor Ceropegia is monophyletic. We recover a broad trend, in two separate major lineages, from slender climbers to small, geophytic herbs. Several clades are recovered in which all species possess an underground tuber. Small, erect, non-climbing, geophytic species of Ceropegia with a tuber are nested among species of Brachystelma. Consequently, the distinctive tubular flowers used to define Ceropegia do not reflect relationships. This re-iterates the great floral plasticity in the Ceropegieae, already established for the stapeliads. Both major lineages exhibit a trend from tubular flowers with faint, often fruity odours, pollinated by very small Dipteran flies, to flatter flowers often with a bad odour, pollinated by larger flies. Most of the diversity in Brachystelma and Ceropegia is recent and arose within the last 3my against a background of increased aridification or extreme climatic variability during the Pliocene. In the ingroup, diversity is highest in Southern Africa, followed by Tropical East Africa and other arid parts of Africa, the Arabian Peninsula and India. Many disjunctions are revealed and these are best explained by recent, long distance dispersal. In Africa, the diversity arises from the presence of many different lineages over

  13. Background gamma radiation monitoring of three clusters of villages surrounding Mohuldih, Banduhurang and Bagjata villages, the proposed uranium mining areas in Singhbhum, Jharkhand

    International Nuclear Information System (INIS)

    Generation of power is a fundamental catalyst to the social and economic development of a country. India needs more power in order to have a strong industrial base and for infrastructure development. With this in view, there has been an emphasis on nuclear power as an alternative source in the field of electricity generation as the nuclear power can be an effective tool in reducing stress on the environment. The Singhbhum district in the state of Jharkhand in India has been known to have deposits of uranium and uranium mines like Jaduguda, Narwapahar, Bhatin etc have been operating in the region. With the increased requirement of electricity and hence suitable fuel, few more sites are proposed to mine uranium in the region. The sites proposed are near the villages of Mohuldih, Banduhurang and Bagjata and are proposed to be open cast mines. These areas of Singhbhum are not economically advanced areas. By and large, the population is poor and there are existing problems like malnutrition and poor health. The activities of mining and the associated developments in the region are expected to improve the economic condition of the residents either through direct employment in the mining facilities, or by indirect gains due to infrastructural developments in the region. In order to assess the impact of the mining operations on the environment and the population as well, it is necessary that the pre-operational survey be carried out in the regions in question. As is the practice, a complete pre-operational survey of the physical, chemical and environmental parameters has been carried out in the region. Background gamma radiation survey was also carried out, using the thermo luminescent dosimetry technique, to obtain the preoperational levels prevalent in the regions. This paper gives the results of the baseline background gamma radiation survey in the region. It was observed that the general gamma background levels of the areas, as measured using TLDs, was 1.36 ± 0.41 m

  14. Determination of environmental radioactivity (238U, 232Th and 40K) and indoor natural background radiation level in Chennai city (Tamilnadu State), India.

    Science.gov (United States)

    Babai, K S; Poongothai, S; Punniyakotti, J

    2013-01-01

    An extensive study on the determination of the natural radioactivity ((238)U, (232)Th and (40)K) levels in soil samples of Chennai city, India has been undertaken and the results of the same are compared with the levels reported in other Indian cities as well as other parts of the world. The radioactivity content in the soil samples, the absorbed dose rate, annual effective dose equivalent, radium equivalent activity, internal and external hazard indices were calculated and compared with UNSCEAR 2000 recommended values. In addition to the above, mapping of indoor natural background gamma radiation levels has been made using thermo luminescent dosemeters throughout Chennai city and the same are reported. PMID:22847868

  15. The BOOMERANG North America Instrument a balloon-borne bolometric radiometer optimized for measurements of cosmic background radiation anisotropies from 0.3 to 4 degrees

    CERN Document Server

    Piacentini, F; Bathia, R; Bock, J J; Boscaleri, A; Cardoni, P; Crill, B P; De Bernardis, P; Castillo, H D; De Troia, G; Farese, P; Giacometti, M; Hivon, E F; Hristov, V V; Iacoangeli, A; Lange, A E; Masi, S; Mauskopf, P D; Miglio, L; Netterfield, C B; Palangio, P; Pascale, E; Raccanelli, A; Rao, S; Romeo, G; Ruhl, J E; Scaramuzzi, F

    2001-01-01

    We describe the BOOMERANG North America (BNA) instrument, a balloon-borne bolometric radiometer designed to map the Cosmic Microwave Background (CMB) radiation with 0.3 deg resolution over a significant portion of the sky. This receiver employs new technologies in bolometers, readout electronics, millimeter-wave optics and filters, cryogenics, scan and attitude reconstruction. All these subsystems are described in detail in this paper. The system has been fully calibrated in flight using a variety of techniques which are described and compared. It has been able to obtain a measurement of the first peak in the CMB angular power spectrum in a single balloon flight, few hours long, and was a prototype of the BOOMERANG Long Duration Balloon (BLDB) experiment.

  16. Comment on "Stress induction in the bacteria Shewanella oneidensis and Deinococcus radiodurans in response to below-background ionizing radiation", Castillo, et al. Int. J. Rad. Biol., 2015; Early Online DOI:10.3109/09553002.2015.1062571

    CERN Document Server

    Katz, J I

    2015-01-01

    Castillo, et al. report hormesis by background levels of radiation, at which there is $< 10^{-3}$ ionization per bacterium in a replication time. This suggests radiation products accumulate in the growth medium over much longer times. Experiments are proposed to test this hypothesis.

  17. A map of the cosmic microwave background radiation from the Wilkinson Microwave Anisotropy Probe (WMAP), showing the large-scale fluctuations (the quadrupole and octopole) isolated by an analysis done partly by theorists at CERN.

    CERN Multimedia

    2004-01-01

    A recent analysis, in part by theorists working at CERN, suggests a new view of the cosmic microwave background radiation. It seems the solar system, rather than the universe, causes the radiation's large-scale fluctuations, similar to the bass in a song.

  18. The world's high background natural radiation areas (HBNRAs) revisited: A broad overview of the dosimetric, epidemiological and radiobiological issues

    International Nuclear Information System (INIS)

    The residents of the world's high background natural radiation areas (HBNRAs), such as Ramsar (in Iran), Guarapari (in Brazil), Orissa and Kerala (in India) and Yangjiang (in China) have lived in these areas for generations under extraordinary radiation fields. The failure of earlier epidemiological studies to report any substantial increase in cancer incidence in HBNRAs has raised some controversy regarding the validity of the linear no-threshold hypothesis. This paper reviews some of the most recent studies of HBNRAs with the intent of stimulating greater research interest in the dosimetric, epidemiological and radiobiological issues related to the world's HBNRAs and proposes solutions to the challenges facing HBNRA studies. This paper may serve as a useful reference for some of the harder-to-find literature. - Highlights: • Some of the challenging issues of HBNRAs have not been resolved. • A literature review of the most recent studies of HBNRAs has been conducted. • An overview of some of the challenging issues and viable solutions are presented

  19. Assessment of environmental 226Ra, 232Th and 40K concentrations in the region of elevated radiation background in Segamat District, Johor, Malaysia

    International Nuclear Information System (INIS)

    Extensive environmental survey and measurements of gamma radioactivity in the soil samples collected from Segamat District were conducted. Two gamma detectors were used for the measurements of background radiation in the area and the results were used in the computation of the mean external radiation dose rate and mean weighted dose rate, which are 276 nGy h−1 and 1.169 mSv y−1, respectively. A high purity germanium (HPGe) detector was used in the assessment of activity concentrations of 232Th, 226Ra and 40K. The results of the gamma spectrometry range from 11 ± 1 to 1210 ± 41 Bq kg−1 for 232Th, 12 ± 1 to 968 ± 27 Bq kg−1 for 226Ra, and 12 ± 2 to 2450 ± 86 Bq kg−1 for 40K. Gross alpha and gross beta activity concentrations range from 170 ± 50 to 4360 ± 170 Bq kg−1 and 70 ± 20 to 4690 ± 90 Bq kg−1, respectively. These results were used in the plotting of digital maps (using ARCGIS 9.3) for isodose. The results are compared with values giving in UNSCEAR 2000. -- Highlights: • Assessment of the activities in region of elevated radiation in Segamat District. • The average dose rate found to be six times higher than the world average. • The activity of 232Th is six times world average. • The activity of 226Ra is four times and 40K is lower than world average. • A digital map plotted for isodose

  20. Background radiation from fission pulses

    Energy Technology Data Exchange (ETDEWEB)

    England, T.R.; Arthur, E.D.; Brady, M.C.; LaBauve, R.J.

    1988-05-01

    Extensive source terms for beta, gamma, and neutrons following fission pulses are presented in various tabular and graphical forms. Neutron results from a wide range of fissioning nuclides (42) are examined and detailed information is provided for four fuels: /sup 235/U, /sup 238/U, /sup 232/Th, and /sup 239/Pu; these bracket the range of the delayed spectra. Results at several cooling (decay) times are presented. For ..beta../sup -/ and ..gamma.. spectra, only /sup 235/U and /sup 239/Pu results are given; fission-product data are currently inadequate for other fuels. The data base consists of all known measured data for individual fission products extensively supplemented with nuclear model results. The process is evolutionary, and therefore, the current base is summarized in sufficient detail for users to judge its quality. Comparisons with recent delayed neutron experiments and total ..beta../sup -/ and ..gamma.. decay energies are included. 27 refs., 47 figs., 9 tabs.

  1. Radiation

    International Nuclear Information System (INIS)

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  2. Terrestrial gamma dose rate, radioactivity and radiological hazards in the rocks of an elevated radiation background in Juban District, Ad Dali' Governorate, Yemen.

    Science.gov (United States)

    Abdurabu, Wedad Ali; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Heryansyah, Arien; Alnhary, Anees; Fadhl, Shadi

    2016-03-01

    This study aims to evaluate natural radiation and radioactivity in the rock and to assess the corresponding health risk in a region of elevated background radiation in Juban District, Ad Dali' Governorate, Yemen. The mean external gamma dose rate was 374 nGy h(-1) which is approximately six times the world average. The measured results were used to compute annual effective dose equivalent, collective effective dose and excess lifetime cancer risk, which are 2.298 mSv, 61.95 man Sv y(-1) and 8.043  ×  10(-3), respectively. Rocks samples from different geological formations were analyzed for quantitative determination of (226)Ra, (232)Th and (40)K. The specific activity of the rocks samples ranges from 7  ±  1 Bq Kg(-1) to 12 513  ±  329 Bq Kg(-1) for (232)Th, from 6  ±  1 Bq kg(-1) to 3089  ±  74 Bq kg(-1) for (226)Ra and 702  ±  69 Bq kg(-1) to 2954  ±  285 Bq kg(-1) for (40)K. (232)Th is the main contributor to gamma dose rate from the rock samples. Indicators of radiological health impact, radium equivalent activity and external hazard index are 3738 Bq kg(-1) and 10.10, respectively. The mean external hazard index was ten times unity in the studied locations in Juban District, which is higher than the recommended value. PMID:26909670

  3. Determination of exposure rates from natural background radiation in Khartoum using LiF:Mg,Cu,P (GR-200) and CaSo4: Mn TLD chips

    International Nuclear Information System (INIS)

    The exposure rates from natural background radiation - including terrestrial gamma radiation and the ionizing component of cosmic rays - were measured for the first time in the city of khartoum using two types of TLD materials: LiF:Mg,Cu,P (GR-200) and CaSo4:Mn TLD chips. Measurements were performed at two sites simultaneously, one site was selected on land in the vicinity of the Sudan Atomic Energy Commission, for the purposes of the measurement of the total exposure rate outdoors, while the other site was located on a buoy anchored in the Blue Nile, and was selected to measure the exposure rate due to the ionizing component of cosmic rays. The investigations were conducted for periods of between 5 and 28 days. Calibration was performed on a selected number of dosimeters to determine the exposure rates at each site. The exposure rates from the ionizing component of cosmic rays in Khartoum were found to be respectively 33 nGy.h-1 and 30 nGy.h-1, in the measurements performed within the scope of this work using GR-200 and CaSo4:Mn dosimeters, while the total values for exposure on land were found to be 45 nGy.h-1 and 42 nGy.h-1 respectively. These values compare reasonably well with other national averages reported in the UNSCEAR publication. The comparison of the results for the two dosimetric materials demonstrates both the sensitivity and suitability of GR-200 for the purposes of environmental monitoring (orig.)

  4. X-Ray Ccds for Space Applications: Calibration, Radiation Hardness, and Use for Measuring the Spectrum of the Cosmic X-Ray Background

    Science.gov (United States)

    Gendreau, Keith Charles

    1995-01-01

    This thesis has two distinct components. One concerns the physics of the high energy resolution X-ray charge coupled devices (CCD) detectors used to measure the cosmic X-ray background (XRB) spectrum. The other involves the measurements and analysis of the XRB spectrum and instrumental background with these detectors on board the advanced satellite for cosmology and astrophysics (ASCA). The XRB has a soft component and a hard component divided at ~2 keV. The hard component is extremely isotropic, suggesting a cosmological origin. The soft component is extremely anisotropic. A galactic component most likely dominates the soft band with X-ray line emission due to a hot plasma surrounding the solar system. ASCA is one of the first of a class of missions designed to overlap the hard and soft X-ray bands. The X-ray CCD's energy resolution allows us to spectrally separate the galactic and cosmological components. Also, the resolution offers the ability to test several specific cosmological models which would make up the XRB. I have concentrated on models for the XRB origin which include active galactic nuclei (AGN) as principal components. I use ASCA data to put spectral constraints on the AGN synthesis model for the XRB. The instrumental portion of this thesis concerns the development and calibration of the X-ray CCDs. I designed, built and operated an X-ray calibration facility for these detectors. It makes use of a reflection grating spectrometer to measure absolute detection efficiency, characteristic absorption edge strengths, and spectral redistribution in the CCD response function. Part of my thesis research includes a study of radiation damage mechanisms in CCDs. This work revealed radiation damage-induced degradation in the spectral response to X-rays. It also uncovered systematic effects which affect both data analysis and CCD design. I have developed a model involving trap energy levels in the CCD band gap structure. These traps reduce the efficiency in which

  5. Background Material

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Hyytiäinen, Kari; Saraiva, Sofia;

    2016-01-01

    This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders.......This document serves as a background material to the BONUS Pilot Scenario Workshop, which aims to develop harmonised regional storylines of socio-ecological futures in the Baltic Sea region in a collaborative effort together with other BONUS projects and stakeholders....

  6. Excess lifetime cancer risk projections for populations who lives in high background radiation areas as a useful risk communication to the Brazilian experience

    International Nuclear Information System (INIS)

    The present report aims to demonstrate how lifetime risk projections for residents in HBRAs can be used as a risk communication tool, on the basis of an experience of Monte Alegre, a small city in north of Brazil, which has been economically and socially affected due to rumors of environmental contamination and increased radiation related diseases. A comprehensive radiological characterization have been conducted in Monte Alegre and neighborhood cities Alenquer and Prainha which includes indoor radon concentration, indoor and outdoor external gamma radiation, and natural radionuclides concentration in water and crops. Cumulative dose to specific organs were estimated taking into account the environment exposure pathways. Using the NCI radioepidemiological program (NCJ Rad-Risk), which is based mainly on BEIR VII models, we estimated overall and site-specific lifetime cancer risk (LCR) for males and females based on estimated mean dose of all exposure other than radon. For radon, model from BEIR VI was used to estimate the lifetime lung cancer risk and uncertainties was estimated using Monte Carlo simulation. Adjustment for Brazilian expected survival and baseline cancer risk was considered. We aim to discuss in this report how risk projections can he used as a useful risk communication tool. To provide a sound evaluation, comparisons of the estimated lifetime cancer risk due to the enhanced natural radiation to that estimated for population who lives in normal background cities and also to the general baseline lifetime cancer risk were carried on. The use of risk projections are particularly important given the effects of relatively low doses and hence the quantification of a priori relatively small risk. In conclusion, the Brazilian experience in conducting such small epidemiological studies in residents of HBRAs has demonstrated that these studies have been driven just to attend public expectation and/or regulatory agencies request and were most useful for risk

  7. Mass spectrometric determination of thorium and uranium in human hair and nails in a high background natural radiation area of Serbia

    International Nuclear Information System (INIS)

    The content of elements in human hair and nails can be considered as alternative bio-indicators of public exposure to natural radionuclides and other toxic metals over a long period of months or even years. The level of elements in hair and nails usually reflect their presence in other tissues of body. Hair and nails were collected from a high natural background radiation area in Serbia to analyze the concentration of thorium, uranium and selected trace elements such as Mn, Ni, Cu, Sr, Cd, and Cs using inductively coupled plasma mass spectrometry. Th and U concentrations in hair varied from 0.0002 to 0.0276 μg/g and 0.0002 to 0.0771 μg/g, respectively. The concentration in nail varied from 0.0023 to 0.0564 μg/g and 0.0025 to 0.0447 μg/g, for Th and U, respectively. There was a large variation for other metal's concentrations in hair, which may be due to different geological origin and anthropogenic activities. (author)

  8. Dose-effect relationship of dicentric and ring chromosomes in lymphocytes of individuals living in the high background radiation areas in China

    International Nuclear Information System (INIS)

    Chromosomes of 39 healthy family members (3 generations from 13 families) living both in the high-level background radiation areas (HBRA) and the control areas (CA) were studied. Cumulative dose from birth to the time of blood sampling was estimated by calculating measured exposure rate in each individual. The cumulative doses ranged 30.9-358.9 and 6.0-59.2 mGy for HBRA and CA, respectively. Peripheral lymphocyte chromosome preparations were made according to our improved method. Dicentric and ring chromosomes (Dic+Rc) were scored in average 2,527 cells per individual in HBRA and 2,694 cells in CA under a microscope equipped with an automated stage. A positive correlation between Dic+Rc and age was found in HBRA, while no such dose relationship was clear in CA. The frequency of Dic+Rc linearly increases over lifetime due to chronic low dose exposure and it is likely that the activation of repair enzymes is not triggered in the present HBRA. Threshold dose (rate) of the induction of chromosome aberrations, if any, is below the present dose (rate) level. (author)

  9. Excess relative risk for solid cancer mortality during prolonged exposure to high-background natural radiation in Yangjiang area of China

    International Nuclear Information System (INIS)

    Objective: To estimate the excess relative risk for solid cancer associated with chronically exposure to high-background natural radiation in Yangjiang area of China. Methods: Based on hamlet-specific environmental doses and sex-and age-specific occupancy factors, the authors calculated cumulative doses for each cohort member. Assuming a linear dose response relationship and using cancer mortality data for the period 1979-1995 and Poisson model, the authors estimated the excess relative risk (ERR) for solid cancer. Results: The ERR per Sv of all solid cancer is estimated to be -0.11 (95% CI, -0.67, 0.69 to 95%). The corresponding figures for cancers of liver, nasopharynx, lungs and stomach are -0.99 (-1.60, 0.10), 0.10 (-1.21, 3.28), -0.68 (-1.58, 1.66) and -0.27 (-1.37, 2.69) respectively. Conclusion: The association between ERR of solid cancer and dose can not be found

  10. Analysis of internal exposure associated with consumption of crops and groundwater from the high background radiation area of Mrima Hill, Kenya

    International Nuclear Information System (INIS)

    Specific concentrations of 226Ra, 232Th and 40K were measured in cassava tubers, cassava leaves and groundwater obtained from the high background radiation area of Mrima hill and used in the evaluation of the ingested dose. Cassava tubers, cassava leaves and groundwater registered average 226Ra concentrations of 60 ± 5, 141 ± 11 and 4.3 ± 0.3 Bq kg-1, respectively. 232Th was not detected in cassava leaves although it was present in cassava tubers as well as in groundwater in average concentrations of 35.3±61.5 and 2.0±0.1 Bq kg-1, respectively. 40K was present in all samples in average concentrations of 842±539 Bq kg-1 in cassava tubers, 1708 ± 552 Bq kg-1 in cassava leaves and 91.4 Bq kg-1 in groundwater. The total annual effective dose due to ingestion was found to be 7.9 mSv y-1 of which 2.4 mSv y-1 was due to cassava tubers, 3.8 mSv y-1 due to cassava leaves and 1.7 mSv y-1 due to water. (authors)

  11. Biosorption of cadmium by Brevundimonas sp. ZF12 strain, a novel biosorbent isolated from hot-spring waters in high background radiation areas

    Energy Technology Data Exchange (ETDEWEB)

    Masoudzadeh, Nasrin [Department of Molecular Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), P.O. Box 14155-6343, Tehran (Iran, Islamic Republic of); Department of Biology, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zakeri, Fardideh [Department of Molecular Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), P.O. Box 14155-6343, Tehran (Iran, Islamic Republic of); National Radiation Protection Department - Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Lotfabad, Tayebe bagheri [Department of Molecular Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), P.O. Box 14155-6343, Tehran (Iran, Islamic Republic of); Sharafi, Hakimeh [Department of Molecular Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), P.O. Box 14155-6343, Tehran (Iran, Islamic Republic of); Department of Biology, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Masoomi, Fatemeh; Zahiri, Hoseein Shahbani; Ahmadian, Gholamreza [Department of Molecular Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), P.O. Box 14155-6343, Tehran (Iran, Islamic Republic of); Noghabi, Kambiz Akbari, E-mail: Akbari@nigeb.ac.ir [Department of Molecular Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), P.O. Box 14155-6343, Tehran (Iran, Islamic Republic of)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Isolation and characterization of a novel cadmium-biosorbent (Brevundimonas sp. ZF12) from high background radiation areas. Black-Right-Pointing-Pointer Brevundimonas sp. ZF12 caused 50% removal of cadmium at the concentration level of 250 ppm. Black-Right-Pointing-Pointer Solution pH values used for the reusability study have powerful desorptive features to recover Cd ions sorbed onto the biomass. Black-Right-Pointing-Pointer This is the first study carried out so far for the cadmium removal from aqueous solutions by a novel biosorbent Brevundimonas sp. ZF12. Black-Right-Pointing-Pointer In our opinion, the isolate can be an attractive alternative to remove the cadmium-containing wastewaters. - Abstract: The aim of this study is to screen cadmium biosorbing bacterial strains isolated from soils and hot-springs containing high concentrations of radium ({sup 226}Ra) in Ramsar using a batch system. Brevundimonas sp. ZF12 strain isolated from the water with high {sup 226}Ra content caused 50% removal of cadmium at a concentration level of 250 ppm. The biosorption equilibrium data are fitted well by the Langmuir adsorption isotherm and kinetic studies indicated that the biosorption follows pseudo second-order model. The effect of different physico-chemical parameters like biomass concentration, pH, cadmium concentration, temperature and contact time on cadmium sorption was also investigated using FTIR, SEM and XRD analytical techniques. A high desorption efficiency (above 90%) was obtained using a pH range of 2.0-4.0. Reusability of the biomass was examined under consecutive biosorption-desorption cycles repeated thrice. In conclusion, Brevundimonas sp. ZF12 is proposed as an excellent cadmium biosorbent that may have important applications in Cd removal from wastewaters.

  12. Radiogenic and Dosimetric Characteristics of Artisanal Mining of a High Background Radiation Area (HBRA) ‘Conflict Mineral’ Columbite-Tantalite

    International Nuclear Information System (INIS)

    The paper reports on the radiogenic and dosimetric study of extraction and processing of a ‘conflict mineral’ columbite-tantalite (coltan) in Rwanda using gamma-ray spectrometry and multivariate chemometrics. The study was motivated by the need for evidence-based development of a radiological regulatory framework for artisanal mining of conflict minerals in high background radiation areas (HBRA), which is widespread in Eastern Africa; and for furnishing a rapid method for forensic and quality assurance of coltan mining and trade utilizing coltan ore gamma-ray spectra as unique geochemical fingerprints. The mean activity concentrations of 238U and 232Th in mined coltan were 513 Bq kg-1 and 57 Bq kg-1 respectively, while that of 40K was 267 Bq kg-1. Measured absorbed dose rates varied 518.34 - 796.92 nGy h-1, 522.4 - 820.7 nGy h-1 and 563.8 - 845.7 nGy h-1 in Muhanga, Ruli and Ngoma respectively; these values are 11 times higher than world average, showing Rwanda’s coltan mining belt is a HBRA. Measured dose rates were twice higher than computed rates based on measured radionuclide activities, indicating the significance of gamma dose from radioactive dust and radon. Calculation of effective doses according to exposure pathways and working scenarios showed that total effective doses vary 0.0173 - 0.272 mSv y-1 in Muhanga, 0.013 - 0.525 mSv y-1 in Ruli and 0.022 - 0.255 mSv y-1 in Ngoma; inhalation of coltan bearing dust accounts for 98 % of the total exposure. It was found that processing coltan enhances the concentration of 232Th and 238U by a factor of 3 and 2 respectively, while it reduces that of 40K by a factor of 15. Principal component analysis (PCA) of the radionuclides source-apportioned coltan accurately to the respective mining areas and differentiated extracted from processed coltan. Although PCA also showed that artisanal mining practices hardly contribute to radiogenic pollution of the environment, results of this study raise important

  13. The Swedish Radiation Protection Institute's regulations concerning the final management of spent nuclear fuel and nuclear waste - with background and comments

    International Nuclear Information System (INIS)

    This report presents and comments on the Swedish Radiation Protection Institute's Regulations concerning the Protection of Human Health and the Environment in connection with the Final Management of Spent Nuclear Fuel or Nuclear Waste, SSI FS 1998: 1

  14. Are the Inhabitants of High Background Radiation Areas of Ramsar More Radioresistant? Scope of the Problem and the Need for Future Studies

    Directory of Open Access Journals (Sweden)

    A. Esmaili

    2003-05-01

    Full Text Available Backgroud/Objective: Ramsar in northern Iran is among the world’s well-known areas with highest levels of natural radiation. Annual exposure levels in areas with elevated levels of natural radiation in Ramsar are up to 260 mGy y-1 and average exposure rates are about 10 mGy y-1 for a population of about 2000 residents. Due to the local geological features, which includes high levels of radium in rocks, soils, and groundwater, Ramsar residents are also exposed to high levels of alpha activity in the form of ingested radium and radium decay progeny as well as very high radon levels (over 1000 MBq m-3 in their dwellings. In some cases, the inhabitants of these areas receive doses much higher than the current ICRP-60 dose limit of 20 mSv y-1 set for radiation workers. The extraordinary levels of natural radiation in Ramsar prompted us to assess the radiation susceptibility of the residents. Material and methods: Venous blood samples were taken from 7 healthy blood donors of both sexes who lived in some areas of Ramsar with highest levels of natural radiation (dose rates were up to 155 µSv h-1 and 5 healthy persons from a nearby control area. Standard condition for cell cultivation, irradiation and analysis of chromosome aberrations was used. The cells were exposed to the challenge dose of 1.5 Gy of Co-60 gamma ray 48 hours after PHA stimulation. Using mean chromosomal aberration per cell (MCAPC, the expected numbers of aberrations were calculated. Results:Lymphocytes of Ramsar residents when subjected to 1.5 Gy of Gamma rays, showed fewer chromosome aberrations compared to residents in a nearby control area. These findings clearly show that high levels of natural radiation may induce radioadaptive response. Interestingly, Conclusion: this radioadaptation phenomenon was found in individuals who received doses as much as a few hundred times more than the inhabitants of a nearby control area. More research is needed to precisely clarify if it is

  15. The environmental monitoring of the natural radiation background in Antarctica with LiF:Mg,Cu,P TLD and X-γ radiometry

    International Nuclear Information System (INIS)

    This paper describes the experimental results obtained with an X-γ radiometer and LiF:Mg,Cu,P thermoluminescence detectors for the measurement of natural radiation in the Antarctic region (China Zhongshan Station). Two methods were adopted for the investigation: (1) thermoluminescence detectors for integrated dose; (2) X-γ radiometer (type BH3013) for the distribution of the dose rate. The experimental results show that the distribution of natural radiation levels in Antarctica is very uneven. The maximum difference in the values of the dose rate observed was 20 times. Further studies are needed to explain these results fully. (author)

  16. The Swedish Radiation Protection Institute's regulations concerning the final management of spent nuclear fuel and nuclear waste - with background and comments

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-11-01

    This report presents and comments on the Swedish Radiation Protection Institute's Regulations concerning the Protection of Human Health and the Environment in connection with the Final Management of Spent Nuclear Fuel or Nuclear Waste, SSI FS 1998: 1.

  17. Transformation of the angular power spectrum of the Cosmic Microwave Background (CMB) radiation into reciprocal spaces and consequences of this approach

    Czech Academy of Sciences Publication Activity Database

    Červinka, Ladislav

    2011-01-01

    Roč. 2, č. 11 (2011), s. 1331-1347. ISSN 2153-120X Institutional research plan: CEZ:AV0Z10100521 Keywords : CMB radiation * analysis of CMB spectrum * radial distribution function of objects * early universe cluster structure * density of ordinary matter Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  18. Morphological and transcriptional response of an anhydrobiotic insect to ionizing radiation and desiccation: steps forward in understanding molecular background of extreme radioresistance in higher eukaryotes

    Science.gov (United States)

    Gusev, Oleg; Novikova, Nataliya; Sychev, Vladimir; Okuda, Takashi; Kikawada, Takahiro; Sakashita, Tetsuya; Mukae, Kyosuke

    2012-07-01

    Life in extreme or drastically changing environments in many cases leads to evolutionary evolvement of mechanisms of cross-resistance to different abiotic stresses, often never actually faced by the organism in its natural habitat. Larvae of the sleeping chironomidPolypedilum vanderplanki (Diptera) are able to resist complete desiccation and in the dry form survive under excess of various abiotic stresses, including exposure to space environment. One of the most intriguing features of the anhydrobiotic larvae is resistance to extremely high doses of different types of ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the structural changes in the nuclear DNA using transmission electron microscopy and DNA comet assays in relation to anhydrobiosis and radiation. We find that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. The DNA fragmentation level and the recovery of DNA integrity in the rehydrated after anhydrobiosis larvae were similar to those of hydrated larvae irradiated with 70 Gy of high-linear energy transfer (LET) ions (4He+). In comparison, low-LET radiation (gamma rays) of the same dose causes less initial damage to the larvae, and recovery of DNA repair is complete within 24 h. Genome-wide analysis of mRNA expression in the larvae revealed that a large group of genes (including antioxidants, anhydrobiosis-specific biomolecules and protein-reparation enzymes) showed a similar patterns of activity in response to both desiccation and ionizing radiation. We conclude that t one of the factors explaining the relationship between the resistance to ionizing radiation and the ability to undergo anhydrobiosis in the sleeping chironomid would be an adaptation to desiccation-inflicted proteins and nuclear DNA damage.

  19. JEM-X background models

    DEFF Research Database (Denmark)

    Huovelin, J.; Maisala, S.; Schultz, J.;

    2003-01-01

    revolution 41 of INTEGRAL. Total observing time used for the analysis was 216 502 s, with the average of 25 cps of background for each of the two JEM-X telescopes. JEM-X1 showed slightly higher average background intensity than JEM-X2. The detectors were stable during the long exposures, and weak orbital...... phase dependence in the background outside radiation belts was observed. The analysis yielded an average of 5 cps for the diffuse background, and 20 cps for the instrument background. The instrument background was found highly dependent on position, both for spectral shape and intensity. Diff use...... background was enhanced in the central area of a detector, and it decreased radially towards the edge, with a clear vignetting effect for both JEM-X units. The instrument background was weakest in the central area of a detector and showed a steep increase at the very edges of both JEM-X detectors, with...

  20. Distortion of the Microwave Blackbody Background Radiation Implied by the Baryon-symmetric Cosmology of Omnes and the Galaxy Formation Theory of Stecker and Puget

    Science.gov (United States)

    Stecker, F. W.; Puget, J. L.

    1973-01-01

    Theories on the evolution of the universe are evaluated. Particular attention was given to Omnes and Stecker and Puget theories. Data cover distortion of the microwave black body background energy distribution at red shifts between 10,000 and 1.000, and black body distortion due to antimatter and annihilation reactions.

  1. Hubble diagrams of soft and hard radiation sources in the graviton background: to an apparent contradiction between supernova 1a and gamma-ray burst observations

    OpenAIRE

    Ivanov, Michael A.

    2006-01-01

    In the sea of super-strong interacting gravitons, non-forehead collisions with gravitons deflect photons, and this deflection may differ for soft and hard radiations. As a result, the Hubble diagram would not be a universal function and it will have a different view for such sources as supernovae in visible light and gamma-ray bursts. Observations of these two kinds are compared here with the limit cases of the Hubble diagram.

  2. Radiation

    International Nuclear Information System (INIS)

    The basic facts about radiation are explained, along with some simple and natural ways of combating its ill-effects, based on ancient healing wisdom as well as the latest biochemical and technological research. Details are also given of the diet that saved thousands of lives in Nagasaki after the Atomic bomb attack. Special comment is made on the use of radiation for food processing. (U.K.)

  3. Temperature Measurement of a Miniature Ceramic Heater in the Presence of an Extended Interfering Background Radiation Source Using a Multiwavelength Pyrometer

    Science.gov (United States)

    Ng, Daniel

    1999-01-01

    Temperature measurement of small (millimeter size) objects is generally difficult and demanding. Measurement involving ceramic materials using the traditional one- and two-color pyrometer is difficult because of their complex optical properties, such as low emissivity which may vary with both temperature and wavelength. Pyrometry applications in an environment with an interfering radiation source of extended dimension adds extra complexity to the process. We show that the multiwavelength pyrometer successfully measured the temperatures of a millimeter (mm) size ceramic heater under these demanding conditions.

  4. Radiation

    International Nuclear Information System (INIS)

    Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capita per year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man-made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man-made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well-conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120

  5. Estimation of aerosol radiative forcing over an aged-background aerosol feature during advection and non-advection events using a ground-based data obtained from a Prede Skyradiometer observation

    Science.gov (United States)

    Ningombam, Shantikumar S.; Bagare, S. P.; Khatri, P.; Sohn, B. J.; Song, H.-J.

    2015-10-01

    Estimation of aerosol radiative forcing (ARF) was performed using a radiative transfer model (Rstar6b) along with physical and optical parameters of aerosols obtained from sky radiometer observation over Indian Astronomical Observatory (IAO), Hanle, Ladakh, during 2008-2010 from dust, anthropogenic, and aged background observing conditions. ARF was estimated at the top of the atmosphere (TOA), in the atmosphere, and at the surface during the three observing conditions. During dust and anthropogenic events, average aerosol optical depth (AOD at 500 nm) went up to 0.24 from the aged background observing condition 0.04. Such enhancement of AOD is associated by the combination of desert-dust and anthropogenic aerosols transported from distant sources as noticed from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Such three types of aerosols are also identified from the observed properties of single scattering albedo (SSA), aerosol asymmetry (AS) parameter, and aerosol size distribution. The estimated ARFs at TOA, at the surface, and in atmosphere are - 3.73, - 6.82, and 3.40 Wm- 2, respectively during the dust advection period. On the contrary, the respective ARFs during the aged background observing condition are - 1.50, - 2.22, and 0.70 Wm- 2, respectively. A significant difference of spectral AOD is observed during dust, anthropogenic, and aged background observing conditions. Ångström exponent (AE) decreases from 1.05 in the aged background observing condition to 0.40 in the dust event. A significant difference of coarse-fine mode volume distribution is also observed between the dust and the anthropogenic cases. Further, the study reveals high aerosols induced during the dust and the anthropogenic episodes caused warming at atmosphere and cooling at surface which collectively may affect the local atmospheric circulation.

  6. Earth X-ray albedo for cosmic X-ray background radiation in the 1--1000 keV band

    OpenAIRE

    Churazov, E.; Sazonov, S.; Sunyaev, R.; Revnivtsev, M.

    2006-01-01

    We present calculations of the reflection of the cosmic X-ray background (CXB) by the Earth's atmosphere in the 1--1000 keV energy range. The calculations include Compton scattering and X-ray fluorescent emission and are based on a realistic chemical composition of the atmosphere. Such calculations are relevant for CXB studies using the Earth as an obscuring screen (as was recently done by INTEGRAL). The Earth's reflectivity is further compared with that of the Sun and the Moon -- the two oth...

  7. Changed level of peripheral blood red cell total and membrane-bound catalase in liquidators of the consequences of the Chernobyl Power Plant accident and in residents pf a zone with increased radiation background

    International Nuclear Information System (INIS)

    Liquidators of the Chernobyl accident and men permanently living in a zone with increased radiation background were examined 7.5 years after the accident. Use of tests characterizing the status of adaptation systems and defence reactions of the organism helped detect disorders in oxidative balance, to which the production of biooxidants by activated neutrophils and attenuated activity of blood catalase essentially contribute. The prooxidant shift results in injury to cell membranes manifested by the reduction of their enzyme-binding capacity. These shifts homeostasis disorders may create prerequisites for increase of morbidity of the examined populations due to disorders in the adaptation mechanisms

  8. Evaluating the effectiveness of the treatment of inflammatory periodontal disease on a background of chronic cholecystitis with the combined effect of the running of the alternating magnetic fields and low-intensity laser radiation

    Directory of Open Access Journals (Sweden)

    Dyakova E.S.

    2011-03-01

    Full Text Available The aim of the study was to determine the characteristic clinical, instrumental and diagnostic criteria of inflammatory periodontal diseases on the background of chronic cholecystitis with subsequent evaluation of the effectiveness of therapeutic measures using the combined action of the running of an alternating magnetic field and low-intensity helium-neon laser. Application low-intensiti laser radiation and a running variable magnetic field in complex treatment of patients periodontitis with cholecystitis expressed anti-inflammatory action allows to stop quickly inflammatory process in periodontium and to reduce treatment terms

  9. CONTRIBUTION OF GAMMA-RAY-LOUD RADIO GALAXIES' CORE EMISSIONS TO THE COSMIC MeV AND GeV GAMMA-RAY BACKGROUND RADIATION

    International Nuclear Information System (INIS)

    The Fermi gamma-ray satellite has recently detected gamma-ray emissions from radio galaxy cores. From these samples, we first examine the correlation between the luminosities at 5 GHz, L5GHz, and at 0.1-10 GeV, Lγ, of gamma-ray-loud radio galaxies. We find that the correlation is significant with Lγ∝L1.165GHz based on a partial correlation analysis. Using this correlation and the radio luminosity function (RLF) of radio galaxies, we explore the contribution of gamma-ray-loud radio galaxies to the unresolved extragalactic gamma-ray background (EGRB). The gamma-ray luminosity function is obtained by normalizing the RLF to reproduce the source-count distribution of the Fermi gamma-ray-loud radio galaxies. We find that gamma-ray-loud radio galaxies can explain ∼25% of the unresolved Fermi EGRB flux above 100 MeV and will also make a significant contribution to the EGRB in the 1-30 MeV energy band. Since blazars explain 22% of the EGRB above 100 MeV, radio-loud active galactic nucleus populations explain ∼47% of the unresolved EGRB. We further make an interpretation on the origin of the EGRB. The observed EGRB spectrum at 0.2-100 GeV does not show an absorption signature by the extragalactic background light. Thus, the dominant population of the origin of EGRB at very high energy (>30 GeV) might be either nearby gamma-ray-emitting sources or sources with very hard gamma-ray spectra.

  10. Background canceling surface alpha detector

    International Nuclear Information System (INIS)

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

  11. Minimizing the background radiation in the new neutron time-of-flight facility at CERN FLUKA Monte Carlo simulations for the optimization of the n_TOF second experimental line

    CERN Document Server

    Bergström, Ida; Elfgren, Erik

    2013-06-11

    At the particle physics laboratory CERN in Geneva, Switzerland, the Neutron Time-of-Flight facility has recently started the construction of a second experimental line. The new neutron beam line will unavoidably induce radiation in both the experimental area and in nearby accessible areas. Computer simulations for the minimization of the background were carried out using the FLUKA Monte Carlo simulation package. The background radiation in the new experimental area needs to be kept to a minimum during measurements. This was studied with focus on the contributions from backscattering in the beam dump. The beam dump was originally designed for shielding the outside area using a block of iron covered in concrete. However, the backscattering was never studied in detail. In this thesis, the fluences (i.e. the flux integrated over time) of neutrons and photons were studied in the experimental area while the beam dump design was modified. An optimized design was obtained by stopping the fast neutrons in a high Z mat...

  12. A search for a keV signature of radiatively decaying dark matter with Suzaku XIS observations of the X-ray diffuse background

    Science.gov (United States)

    Sekiya, Norio; Yamasaki, Noriko Y.; Mitsuda, Kazuhisa

    2016-06-01

    We performed the deepest search for an X-ray emission line at between 0.5 and 7 keV from non-baryonic dark matter by the Suzaku XIS. Dark matter associated with the Milky Way was selected as the target to obtain the best signal-to-noise ratio. From the Suzaku archive, we selected 187 data sets of blank-sky regions that were dominated by the X-ray diffuse background. The data sets were from 2005 to 2013. The instrumental responses were adjusted by multiple calibration data sets of the Crab Nebula. We also improved the technique of subtracting lines of instrumental origin. These energy spectra were well described by X-ray emission due to charge exchange around the Solar System, hot plasma in and around the Milky Way, and the superposition of extra-galactic point sources. A signal of a narrow emission-line was searched for, and the significance of detection was evaluated in consideration of the blind search method (the Look-elsewhere Effect). Our results exhibited no significant detection of an emission line feature from dark matter. The 3 σ upper limit for the emission line intensity between 1 and 7 keV was ˜ 10-2 photons cm-2 s-1 sr-1, or ˜ 5 × 10-4 photons cm-2 s-1 sr-1 per M⊙ pc-2, assuming a dark matter distribution with the Galactic rotation curve. The parameters of sterile neutrinos as candidates of dark-matter were also constrained.

  13. Spatial and vertical distributions of heavy metals and their potential toxicity levels in various beach sediments from high-background-radiation area, Kerala, India

    International Nuclear Information System (INIS)

    Graphical abstract: Graphical representation shows that concentrations of Cd and Pb and all the calculated indexes might have been influenced by the amount of total organic content and the Ni and Zn concentrations might have been influenced by sediment grain size (silt and clay). - Highlights: • Most of the metals are higher in S1 and other higher values are erratically distributed. • Moderate and severe degree of ecological risk is observed in different layers. • Surface and first feet samples had 21%, third feet samples had 49% of probability of toxicity. • Most of the studied metals and all calculated indexes are higher in third feet samples. • The calculated indexes might have been influenced by amount of total organic content. - Abstract: The spatial and vertical distribution of heavy metals and the sediment characteristics of beaches in Kerala, India (the upper surface sediments and the first, second and third one-foot-thick strata) were assessed in this study. The concentrations of most of the studied metals were highest at sampling site S1 (Cochin). The measured concentrations were compared with background and toxicological reference values. The results show that definite adverse biological effects are possible at most of the sampling sites due to the high Pb levels. Three different indexes were calculated to investigate the potential toxicity level. Most of the studied metals and all calculated indexes were highest in the third foot of sediment. Multivariate statistical analyses were performed and suggested that particular heavy metals, e.g., Pb, Cd, Cr and Ni, may represent contamination from a common source. The Cd and Pb concentrations and all the calculated index values show a relationship with the content of organic matter. The results of the present study suggest the recommendation that a systematic analysis is needed to monitor heavy metal levels in the studied area

  14. Distribution of uranium, thorium and some stable trace and toxic elements in human hair and nails in Niška Banja Town, a high natural background radiation area of Serbia (Balkan Region, South-East Europe)

    International Nuclear Information System (INIS)

    Human hair and nails can be considered as bio-indicators of the public exposure to certain natural radionuclides and other toxic metals over a long period of months or even years. The level of elements in hair and nails usually reflect their levels in other tissues of body. Niška Banja, a spa town located in southern Serbia, with locally high natural background radiation was selected for the study. To assess public exposure to the trace elements, hair and nail samples were collected and analyzed. The concentrations of uranium, thorium and some trace and toxic elements (Mn, Ni, Cu, Sr, Cd, and Cs) were determined using inductively coupled plasma mass spectrometry (ICP-MS). U and Th concentrations in hair varied from 0.0002 to 0.0771 μg/g and from 0.0002 to 0.0276 μg/g, respectively. The concentrations in nails varied from 0.0025 to 0.0447 μg/g and from 0.0023 to 0.0564 μg/g for U and Th, respectively. We found significant correlations between some elements in hair and nails. Also indications of spatial clustering of high values could be found. However, this phenomenon as well as the large variations in concentrations of heavy metals in hair and nail could not be explained. As hypotheses, we propose possible exposure pathways which may explain the findings, but the current data does not allow testing them. - Highlights: • Niška Banja is a high radiation background area of Serbia with high radium (226Ra) concentration. • Measurement of thorium, uranium and some selected trace elements in hair and nails were carried out using ICP-MS. • Elevated concentration of naturally occurring radionuclides such as U and Th in environmental samples was determined. • We have assumed to find a suitable relationship between hair and nail samples with the natural samples

  15. Hanford Site background: Part 3, Groundwater background

    International Nuclear Information System (INIS)

    This report presents and interprets groundwater background data collected from the unconfined aquifer beneath the Hanford Site, a U.S. Department of Energy complex located near Richland, Washington. Characterization of background composition is an important component of environmental characterization activities and serves as a basis for distinguishing the presence and significance of contamination. Background data can also be used to assess the levels of baseline risk to which humans or other receptors are typically exposed and to establish remediation goals. Evaluating background on a sitewide basis provides a consistent, technically defensible definition of background as opposed to determining area-specific background compositions for each waste management unit being considered for remediation across the Hanford Site

  16. Cosmic Background Radiation Mini-Review

    OpenAIRE

    Scott, Douglas; Smoot, George

    2004-01-01

    This is a complete re-write of the mini-review for the Review of Particle Physics (a.k.a the Partcicle Data Book), which includes an assessment of the CMB anisotropy results and their interpretation up until the end of 2003. It forms a compact overview of the field at this time. Sections headings are: Introduction; Description of CMB Anisotropies; Cosmological Parameters; Physics of Anisotropies; Current Anisotropy Data; CMB Polarization; Complications; Constraints on Cosmologies; Particle Ph...

  17. Cosmic Background Radiation Mini-Review

    CERN Document Server

    Scott, D; Scott, Douglas; Smoot, George

    2004-01-01

    This is a complete re-write of the mini-review for the Review of Particle Physics (a.k.a the Partcicle Data Book), which includes an assessment of the CMB anisotropy results and their interpretation up until the end of 2003. It forms a compact overview of the field at this time. Sections headings are: Introduction; Description of CMB Anisotropies; Cosmological Parameters; Physics of Anisotropies; Current Anisotropy Data; CMB Polarization; Complications; Constraints on Cosmologies; Particle Physics Constraints; Fundamental Lessons; and Future Directions.

  18. The isotropic radio background revisited

    CERN Document Server

    Fornengo, Nicolao; Regis, Marco; Taoso, Marco

    2014-01-01

    We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emi...

  19. Change of Primary Cosmic Radiation Nuclear Conposition in the Energy Range $10^{15} - 10^{17}$ eV as a Result of the Interaction with the Interstellar Cold Background of Light Particles

    CERN Document Server

    Barnaveli, T T; Khaldeeva, I V

    2003-01-01

    In this paper the updated arguments in favor of a simple model, explaining from the united positions all peculiarities of the Extensive Air Shower (EAS) hadron E_h(E_0) (and muon E_mu(E_0)) component energy fluxes dependence on the primary particle energy E_0 in the primary energy region 10^{15} - 10^{17} eV are represented. These peculiarities have shapes of consequent distinct deeps of a widths dE_h/E_h of the order of 0.2 and of relative amplitudes dL/L of the order of {0.1 - 1.0}, and are difficult to be explained via known astrophysical mechanisms of particle generation and acceleration. In the basis of the model lies the destruction of the Primary Cosmic Radiation (PCR) nuclei on some monochromatic background of interstellar space, consisting of the light particles of the mass in the area of 36 eV (maybe the component of a dark matter). The destruction thresholds of PCR different nuclear components correspond to the peculiarities of E_h(E_0). In this work the results of the recent treatment of large sta...

  20. Distribution of uranium, thorium and some stable trace and toxic elements in human hair and nails in Niška Banja Town, a high natural background radiation area of Serbia (Balkan Region, South-East Europe).

    Science.gov (United States)

    Sahoo, S K; Žunić, Z S; Kritsananuwat, R; Zagrodzki, P; Bossew, P; Veselinovic, N; Mishra, S; Yonehara, H; Tokonami, S

    2015-07-01

    Human hair and nails can be considered as bio-indicators of the public exposure to certain natural radionuclides and other toxic metals over a long period of months or even years. The level of elements in hair and nails usually reflect their levels in other tissues of body. Niška Banja, a spa town located in southern Serbia, with locally high natural background radiation was selected for the study. To assess public exposure to the trace elements, hair and nail samples were collected and analyzed. The concentrations of uranium, thorium and some trace and toxic elements (Mn, Ni, Cu, Sr, Cd, and Cs) were determined using inductively coupled plasma mass spectrometry (ICP-MS). U and Th concentrations in hair varied from 0.0002 to 0.0771 μg/g and from 0.0002 to 0.0276 μg/g, respectively. The concentrations in nails varied from 0.0025 to 0.0447 μg/g and from 0.0023 to 0.0564 μg/g for U and Th, respectively. We found significant correlations between some elements in hair and nails. Also indications of spatial clustering of high values could be found. However, this phenomenon as well as the large variations in concentrations of heavy metals in hair and nail could not be explained. As hypotheses, we propose possible exposure pathways which may explain the findings, but the current data does not allow testing them. PMID:25875006

  1. Building Background Knowledge

    Science.gov (United States)

    Neuman, Susan B.; Kaefer, Tanya; Pinkham, Ashley

    2014-01-01

    This article make a case for the importance of background knowledge in children's comprehension. It suggests that differences in background knowledge may account for differences in understanding text for low- and middle-income children. It then describes strategies for building background knowledge in the age of common core standards.

  2. Background radiation and man-made and sources of radiation

    International Nuclear Information System (INIS)

    This paper describes the development of the use of the atom and its present applications in food and agriculture, industry medicine and health care, energy-environment and research. These applications have inevitably led to concerns about nuclear safety and radioactive waste management and the need for the adoption of procedures for control, safe use and disposal of radioactive sources

  3. The Cosmic Microwave Background

    OpenAIRE

    Silk, Joseph

    2001-01-01

    This set of lectures provides an overview of the basic theory and phenomenology of the cosmic microwave background. Topics include a brief historical review; the physics of temperature and polarization fluctuations; acoustic oscillations of the primordial plasma; the space of inflationary cosmological models; current and potential constraints on these models from the microwave background; and constraints on inflation.

  4. Cosmogenic Backgrounds to 0{\

    CERN Document Server

    :,; Auty, D J; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Didberidze, T; Dilling, J; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Feyzbakhsh, S; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hall, C; Herrin, S; Hughes, M; Jewell, M J; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Krücken, R; Kuchenkov, A; Kumar, K S; Leonard, D S; Licciardi, C; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Njoya, O; Nelson, R; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Retière, F; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2015-01-01

    As neutrinoless double-beta decay experiments become more sensitive and intrinsic radioactivity in detector materials is reduced, previously minor contributions to the background must be understood and eliminated. With this in mind, cosmogenic backgrounds have been studied with the EXO-200 experiment. Using the EXO-200 TPC, the muon flux (through a flat horizontal surface) underground at the Waste Isolation Pilot Plant (WIPP) has been measured to be {\\Phi} = 4.07 $\\pm$ 0.14 (sys) $\\pm$ 0.03 (stat) $\\times$ $10^{-7}$cm$^{-2}$ s$^{-1}$, with a vertical intensity of $I_{v}$ = 2.97$^{+0.14}_{-0.13}$ (sys) $\\pm$ 0.02 (stat) $\\times$ $10^{-7}$cm$^{-2}$ s$^{-1}$ sr$^{-1}$. Simulations of muon-induced backgrounds identified several potential cosmogenic radionuclides, though only 137Xe is a significant background for the 136Xe 0{\

  5. On Background Independence

    OpenAIRE

    Anderson, Edward

    2013-01-01

    This paper concerns what Background Independence itself is (as opposed to some particular physical theory that is background independent). The notions presented mostly arose from a layer-by-layer analysis of the facets of the Problem of Time in Quantum Gravity. Part of this coincides with two relational postulates which are thus identified as classical precursors of two of the facets of the Problem of Time. These are furthemore tied to the forms of each of the GR Hamiltonian and momentum cons...

  6. Zambia Country Background Report

    DEFF Research Database (Denmark)

    Hampwaye, Godfrey; Jeppesen, Søren; Kragelund, Peter

    This paper provides background data and general information for the Zambia studies focusing on local food processing sub­‐sector; and the local suppliers to the mines as part of the SAFIC project (Successful African Firms and Institutional Change).......This paper provides background data and general information for the Zambia studies focusing on local food processing sub­‐sector; and the local suppliers to the mines as part of the SAFIC project (Successful African Firms and Institutional Change)....

  7. The pregalactic cosmic gravitational wave background

    Science.gov (United States)

    Matzner, Richard A.

    1989-01-01

    An outline is given that estimates the expected gravitational wave background, based on plausible pregalactic sources. Some cosmologically significant limits can be put on incoherent gravitational wave background arising from pregalactic cosmic evolution. The spectral region of cosmically generated and cosmically limited radiation is, at long periods, P greater than 1 year, in contrast to more recent cosmological sources, which have P approx. 10 to 10(exp -3).

  8. The pregalactic cosmic gravitational wave background

    International Nuclear Information System (INIS)

    An outline is given that estimates the expected gravitational wave background, based on plausible pregalactic sources. Some cosmologically significant limits can be put on incoherent gravitational wave background arising from pregalactic cosmic evolution. The spectral region of cosmically generated and cosmically limited radiation is, at long periods, P greater than 1 year, in contrast to more recent cosmological sources, which have P approx. 10 to 10(exp -3)

  9. Background estimates for PEP

    International Nuclear Information System (INIS)

    The beam gas bremsstrahlung radiation for PEP has been studied in detail using the ray trace program TURTLE. With this program, an electron (positron) trajectory starting at an interaction region is traced through the storage ring until it radiates, then the radiated electron is traced until it stops in the beam pipe. The relative number of electrons stopping between the strong focusing quadrupoles is used to determine a rate at which electromagnetic showers will occur in the region of the experimental apparatus. It was found that 2.46% of the radiated electrons will stop in the interaction region. Assuming a uniform pressure of 2 x 10/sup /minus/9/ Torr in the vacuum pipe for a residual gas (X/sub o/ = 34.7 gm/cm2), 2.5 x 105 electrons (positrons) will stop in the interaction region per beam (4 x 1012 electrons at 15 GeV) per second. If the luminosity is 1032, this rate is equivalent to a cross section of 2.5 x 10/sup /minus/27/ cm2. 4 figs., 3 tabs

  10. Exploring String Theory Backgrounds

    CERN Document Server

    Williams, B P

    2004-01-01

    This thesis examines phenomenological and theoretical questions by exploring string theoretic backgrounds. Part I focuses on cosmology. First we propose that the induced metric along a brane moving through a curved bulk may be interpreted as the cosmology of the brane universe, providing a resolution to the apparent cosmological singularity on the brane. We then look at various decay channels of the certain meta-stable de Sitter vacua and show that there exist NS5-brane meditated decays which are much faster than decays to decompactification. Part II discusses a new class of nongeometric vacua in string theory. These backgrounds may be described locally as T2 fibrations. By enlarging the monodromy group of the fiber to include perturbative stringy duality symmetries we are able to explicitly construct nongeometric backgrounds.

  11. Unitarity and singular backgrounds

    CERN Document Server

    Brouzakis, Nikos

    2013-01-01

    We compute the graviton Kaluza-Klein spectrum on a gravity-dilaton background with a naked singularity for all possible boundary conditions at the singularity which are consistent with unitary evolution. We apply methods from non-relativistic quantum mechanics with singular Schr\\"{o}dinger potentials. In general the spectrum contains a tachyon, a sign of instability. Only for a particular boundary condition at the singularity the spectrum is free of tachyons. In this case the lowest-lying graviton mode is massless. We argue that this result will also hold for other backgrounds with similar geometry near the curvature singularity. We complete our study with a brief discussion on radion perturbations and Higgs mechanism on this singular background.

  12. Berkeley Low Background Facility

    International Nuclear Information System (INIS)

    The Berkeley Low Background Facility (BLBF) at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background laboratory on the surface at LBNL and at the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products; active screening via neutron activation analysis for U,Th, and K as well as a variety of stable isotopes; and neutron flux/beam characterization measurements through the use of monitors. A general overview of the facilities, services, and sensitivities will be presented. Recent activities and upgrades will also be described including an overview of the recently installed counting system at SURF (recently relocated from Oroville, CA in 2014), the installation of a second underground counting station at SURF in 2015, and future plans. The BLBF is open to any users for counting services or collaboration on a wide variety of experiments and projects

  13. Berkeley Low Background Facility

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, K. J.; Norman, E. B. [Department of Nuclear Engineering, University of California-Berkeley, CA 94720 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, CA 94720 (United States); Smith, A. R.; Poon, A. W. P.; Chan, Y. D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, CA 94720 (United States); Lesko, K. T. [Physics Division, Lawrence Berkeley National Laboratory, CA 94720 (United States)

    2015-08-17

    The Berkeley Low Background Facility (BLBF) at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background laboratory on the surface at LBNL and at the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products; active screening via neutron activation analysis for U,Th, and K as well as a variety of stable isotopes; and neutron flux/beam characterization measurements through the use of monitors. A general overview of the facilities, services, and sensitivities will be presented. Recent activities and upgrades will also be described including an overview of the recently installed counting system at SURF (recently relocated from Oroville, CA in 2014), the installation of a second underground counting station at SURF in 2015, and future plans. The BLBF is open to any users for counting services or collaboration on a wide variety of experiments and projects.

  14. Global Warming and the Microwave Background

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2009-04-01

    Full Text Available In the work, the importance of assigning the microwave background to the Earth is ad- dressed while emphasizing the consequences for global climate change. Climate mod- els can only produce meaningful forecasts when they consider the real magnitude of all radiative processes. The oceans and continents both contribute to terrestrial emis- sions. However, the extent of oceanic radiation, particularly in the microwave region, raises concerns. This is not only since the globe is covered with water, but because the oceans themselves are likely to be weaker emitters than currently believed. Should the microwave background truly be generated by the oceans of the Earth, our planet would be a much less efficient emitter of radiation in this region of the electromagnetic spectrum. Furthermore, the oceans would appear unable to increase their emissions in the microwave in response to temperature elevation, as predicted by Stefan’s law. The results are significant relative to the modeling of global warming.

  15. Gamma background irradiation. Standards and reality

    International Nuclear Information System (INIS)

    The systematic deviation of the results of measuring the power of air dose absorbed from the natural gamma background radiation in Bulgaria is inadmissibly large and variable. This in turn augments the dispersion of results as well as the mean value relative to worldwide data, to an implausible level, hardly attributable to the variegated geographical relief of the country. Thus in practice local anthropogenic increases hardly lend themselves to detection and demonstration. In the Radiation Protection Standards (RPS-92) in effect in Bulgaria, and in other documents concerning the same radiation factors as well, the maximum allowable limits for the population as a whole are clearly specified on the basis of worldwide expertise along this line. As a rule these limits are being exceeded by the actually measured values, and for this reason the cited documents contain a clause stipulating that these limits do not refer to the natural radiation background and therefore the latter may be virtually ignored. Thus the basic risk factor for the population goes beyond control at levels commensurable with the officially established limits, its twofold increase inclusive. The maximum allowable limit becomes undefinable. Bearing in mind the fact that in compliance with the cited RPS-92 elimination of the technogenic ionizing radiation sources incorporated in the environment prior to 1992 is 'freezed', it is evident that exposure of the population to anthropogenic radiation becomes legally allowable in a much wider range than the one specified by world legislators. One may anticipate radiation induced health noxae for the population directly or by anthropogenic radiation stress on biocenosis. A relatively large part of the population is susceptible to the effect of low radiation doses. Presumably this contingent will augment as a result of eventual fluctuations. The casual relationship which is difficult to establish should be given due consideration in the analysis of the causes

  16. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  17. Unitarity and singular backgrounds

    OpenAIRE

    Brouzakis, Nikos; Quiros, Mariano

    2013-01-01

    We compute the graviton Kaluza-Klein spectrum on a gravity-dilaton background with a naked singularity for all possible boundary conditions at the singularity which are consistent with unitary evolution. We apply methods from non-relativistic quantum mechanics with singular Schr\\"{o}dinger potentials. In general the spectrum contains a tachyon, a sign of instability. Only for a particular boundary condition at the singularity is the spectrum free of tachyons. In this case the lowest-lying gra...

  18. Australia; Background Material

    OpenAIRE

    International Monetary Fund

    1995-01-01

    This paper describes the developments in the Australian labor market during the 1990s. In 1994, a number of new labor market programs were launched, directed especially at the long-term unemployed, and a further step was taken in the evolutionary reform of the industrial relations system. The paper reviews developments in employment, wages, and productivity in Australia that formed the background to these policy initiatives. It also examines the conduct of fiscal policy at the Commonwealth an...

  19. Sri Lanka; Background Papers

    OpenAIRE

    International Monetary Fund

    1995-01-01

    This Background Paper on Sri Lanka provides information on the economic developments during 1992–95. Developments in the domestic and external sectors are discussed. The deficiencies of the official consumer price index that resulted in a substantial understatement of inflation performance in 1994 and alternative estimates of underlying inflation are described. The structural rigidities in the labor market that perpetuate high unemployment and limit job growth are also described. The paper ...

  20. Background, phenomenology, and motivation

    International Nuclear Information System (INIS)

    The authors discuss the background to the kinetics of adsorption and desorption after an elementary introduction to the problem of chemisorption in two limiting cases. Other topics discussed include the thermodynamics of adsorption, reaction mechanisms outside surfaces, and a case history of catalytic hydrogenation of carbon monoxide. Figures show the potential energy barrier as a function of an appropriate reaction coordinate, and bonding of carbon monoxide to platinum metal

  1. Some background about satellites

    Science.gov (United States)

    Burns, Joseph A.

    1986-01-01

    Four tables of planetary and satellite data are presented which list satellite discoveries, planetary parameters, satellite orbits, and satellite physical properties respectively. A scheme for classifying the satellites is provided and it is noted that most known moons fall into three general classes: regular satellites, collisional shards, and irregular satellites. Satellite processes are outlined with attention given to origins, dynamical and thermal evolution, surface processes, and composition and cratering. Background material is provided for each family of satellites.

  2. Radiation and People

    Science.gov (United States)

    Freilich, Florence G.

    1970-01-01

    Describes the development of radiation as a tool of medicine. Includes topics on history of radiation, electromagnetic spectrum, X-ray tubes, high energy machines, radioactive sources, artificial radioactivity, radioactive scanning, units, present radiation background, and effect of radiation on living tissue. (DS)

  3. Contribution to the G{sup 0} experiment about parity violation: calculation and simulation of radiative corrections, study of the background noise; Contribution a l'experience G{sup 0} de violation de la parite: calcul et simulation des corrections radiatives et etude de bruit de fond

    Energy Technology Data Exchange (ETDEWEB)

    Guler, H

    2003-12-01

    In the framework of quantum chromodynamics, the nucleon is made of three valence quarks surrounded by a sea of gluons and quark-antiquark pairs. Only the only lightest quarks (u, d and s) contribute significantly to the nucleon properties. In G{sup 0} we use the property of weak interaction to violate parity symmetry, in order to determine separately the contributions of the three types of quarks to nucleon form factors. The experiment, which takes place at Thomas Jefferson laboratory (USA), aims at measuring parity violation asymmetry in electron-proton scattering. By doing several measurements at different momentum squared of the exchanged photons and for different kinematics (forward angle when the proton is detected and backward angle it will be the electron) will permit to determine separately strange quarks electric and magnetic contributions to nucleon form factors. To extract an asymmetry with small errors, it is necessary to correct all the beam parameters, and to have high enough counting rates in detectors. A special electronics was developed to treat information coming from 16 scintillator pairs for each of the 8 sectors of the G{sup 0} spectrometer. A complete calculation of radiative corrections has been done and Monte Carlo simulations with the GEANT program has permitted to determine the shape of the experimental spectra including inelastic background. This work will allow to do a comparison between experimental data and theoretical calculations based on the Standard Model. (author)

  4. Robustness of cosmic neutrino background detection in the cosmic microwave background

    CERN Document Server

    Audren, Benjamin; Cuesta, Antonio J; Gontcho, Satya Gontcho A; Lesgourgues, Julien; Niro, Viviana; Pellejero-Ibanez, Marcos; Pérez-Ràfols, Ignasi; Poulin, Vivian; Tram, Thomas; Tramonte, Denis; Verde, Licia

    2015-01-01

    The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming species in the temperature and polarisation power spectrum. Previous studies have already proposed a rather generic parametrisation of these fluctuations, that could help to discriminate between the signature of ordinary free-streaming neutrinos, or of more exotic dark radiation models. Current data are compatible with standard values of these parameters, which seems to bring further evidence for the existence of a cosmic neutrino background. In this work, we investigate the robustness of this conclusion under various assumptions. We generalise the definition of an effective sound speed and viscosity speed to the case of massive neutrinos or other dark radiation components experiencing a non-relativistic transition. We show that current bounds on these effectiv...

  5. Backgrounded but not peripheral

    DEFF Research Database (Denmark)

    Hovmark, Henrik

    DDAs in question contribute to the socio-cultural construction of identity, i.e. that they play a rather specific role in discursive communication and socio-cultural meaning construction. On the other hand it is clear that the semantics of the DDAs in question, seen in isolation, is very abstract or...... general; furthermore, the DDAs are backgrounded in discourse. Is it reasonable to claim, rather boldly, that “the informants express their identity in the use of the directional adverb ud ‘out’ etc.”? In the course of this article, however, I suggest that the DDAs in question do contribute to the socio-cultural...

  6. Malaysia; Background Paper

    OpenAIRE

    International Monetary Fund

    1996-01-01

    This Background Paper on Malaysia examines developments and trends in the labor market since the mid-1980s. The paper describes the changes in the employment structure and the labor force. It reviews wages and productivity trends and their effects on unit labor cost. The paper highlights that Malaysia’s rapid growth, sustained since 1987, has had a major impact on the labor market. The paper outlines the major policy measures to address the labor constraints. It also analyzes Malaysia’s r...

  7. Background and introduction

    DEFF Research Database (Denmark)

    Jensen, Per Anker; van der Voordt, Theo; Coenen, Christian

    2012-01-01

    in scope between FM and CREM is that CREM has its focus on real estate as physical and economical assets utilized by an organisation, while FM has a wider service focus. The difference in scope between FM and CREM on one side and B2B marketing on the other is that FM and CREM are related to...... chapter provides important background information to understand the following chapters in this book. Research limitations: The chapter is mainly based on the experience and knowledge of the editors. It does not include original research but provides an introductory overview of the book. Originality...

  8. Family Background and Entrepreneurship

    DEFF Research Database (Denmark)

    Lindquist, Matthew J.; Sol, Joeri; Van Praag, Mirjam;

    Vast amounts of money are currently being spent on policies aimed at promoting entrepreneurship. The success of such policies, however, rests in part on the assumption that individuals are not ‘born entrepreneurs’. In this paper, we assess the importance of family background and neighborhood...... effects as determinants of entrepreneurship. We start by estimating sibling correlations in entrepreneurship. We find that between 20 and 50 percent of the variance in different entrepreneurial outcomes is explained by factors that siblings share. The average is 28 percent. Allowing for differential...... entrepreneurship does play a large role, as do shared genes....

  9. Radiation Chemistry

    Science.gov (United States)

    Wojnárovits, L.

    Ionizing radiation causes chemical changes in the molecules of the interacting medium. The initial molecules change to new molecules, resulting in changes of the physical, chemical, and eventually biological properties of the material. For instance, water decomposes to its elements H2 and O2. In polymers, degradation and crosslinking take place. In biopolymers, e.g., DNS strand breaks and other alterations occur. Such changes are to be avoided in some cases (radiation protection), however, in other cases they are used for technological purposes (radiation processing). This chapter introduces radiation chemistry by discussing the sources of ionizing radiation (radionuclide sources, machine sources), absorption of radiation energy, techniques used in radiation chemistry research, and methods of absorbed energy (absorbed dose) measurements. Radiation chemistry of different classes of inorganic (water and aqueous solutions, inorganic solids, ionic liquids (ILs)) and organic substances (hydrocarbons, halogenated compounds, polymers, and biomolecules) is discussed in concise form together with theoretical and experimental backgrounds. An essential part of the chapter is the introduction of radiation processing technologies in the fields of polymer chemistry, food processing, and sterilization. The application of radiation chemistry to nuclear technology and to protection of environment (flue gas treatment, wastewater treatment) is also discussed.

  10. The Backgrounds Data Center

    Science.gov (United States)

    Snyder, W. A.; Gursky, H.; Heckathorn, H. M.; Lucke, R. L.; Berg, S. L.; Dombrowski, E. G.; Kessel, R. A.

    1993-01-01

    The Strategic Defense Initiative Organization has created data centers for midcourse, plumes, and backgrounds phenomenologies. The Backgrounds Data Center (BDC) has been designated as the prime archive for data collected by SDIO programs. The BDC maintains a Summary Catalog that contains 'metadata,' that is, information about data, such as when the data were obtained, what the spectral range of the data is, and what region of the Earth or sky was observed. Queries to this catalog result in a listing of all data sets (from all experiments in the Summary Catalog) that satisfy the specified criteria. Thus, the user can identify different experiments that made similar observations and order them from the BDC for analysis. On-site users can use the Science Analysis Facility (SAFE for this purpose. For some programs, the BDC maintains a Program Catalog, which can classify data in as many ways as desired (rather than just by position, time, and spectral range as in the Summary Catalog). For example, data sets could be tagged with such diverse parameters as solar illumination angle, signal level, or the value of a particular spectral ratio, as long as these quantities can be read from the digital record or calculated from it by the ingest program. All unclassified catalogs and unclassified data will be remotely accessible.

  11. 广东高本底地区人群氧化损伤及抗氧化水平调查%The effects of low dose radiation on the levels of oxidative damage and antioxidant in population of high background radiation area of Guangdong

    Institute of Scientific and Technical Information of China (English)

    陈慧峰; 郭强之; 刘明; 耿继武; 苏世标

    2015-01-01

    目的 探讨长期连续天然放射性照射对人群氧化损伤及抗氧化水平的影响.方法 选择广东天然放射性高本底辐射地区(HBRA)48名男性居民为研究对象,选择恩平市某镇(CA)相匹配的48名男性居民为对照人群.采集2组人群外周静脉血并分离血浆,采用酶联免疫吸附试验(ELISA),测定血浆中DNA氧化损伤指标8-羟基脱氧鸟苷(8-OHdG)和抗氧化指标硫氧还蛋白还原酶(TrxR)的表达水平.结果 与对照组相比,高本底地区人群外周血血浆中DNA氧化损伤指标8-OHdG表达水平由(315.39±100.59) ng/ml降低至(272.64±96.85) ng/ml,抗氧化指标TrxR表达水平由(0.467±0.056) ng/ml升高至(0.496±0.044) ng/ml,两组间的差异均有统计学意义(t=2.121、-2.823,P<0.05).多元线性回归分析结果显示,在排除年龄、饮酒、喝茶、吸烟、接受医疗照射、生活应激事件等混杂因素的影响后,低剂量电离辐射个人累积剂量对8-OHdG和TrxR表达水平均有影响(t=-2.327、2.367,P<0.05).结论 长期接触低剂量电离辐射可降低人群氧化损伤水平,增强机体抗氧化水平.%Objective To investigate the effects of low dose radiation on the level of oxidative damage and antioxidant in population of high background radiation area of Guangdong.Methods A total of 48 male residents who lived in high background radiation area(HBRA) of Guangdong province and 48 male residents who lived in neighboring Enping control area were chosen as the objectives and control respectively.The peripheral venous blood of two groups was collected,and then the levels of 8-OHdG and TrxR were determined by enzyme linked immunosorbent assay (ELISA).Results Compared with the CA group [(315.39 ± 100.59) ng/ml],the level of 8-OHdG [(272.64 ± 96.85) ng/ml] decreased significantly in HBRA (t =2.121,P <0.05).Compared with the CA group [(0.467 ±0.056) ng/ml],the level of TrxR [(0.496 ± 0.044) ng/ml] increased significantly in HBRA (t =-2.823,P

  12. Holography for Schrodinger backgrounds

    CERN Document Server

    Guica, Monica; Taylor, Marika; van Rees, Balt

    2010-01-01

    We discuss holography for Schrodinger solutions of both topologically massive gravity in three dimensions and massive vector theories in (d+1) dimensions. In both cases the dual field theory can be viewed as a d-dimensional conformal field theory (two dimensional in the case of TMG) deformed by certain operators that respect the Schrodinger symmetry. These operators are irrelevant from the viewpoint of the relativistic conformal group but they are exactly marginal with respect to the non-relativistic conformal group. The spectrum of linear fluctuations around the background solutions corresponds to operators that are labeled by their scaling dimension and the lightcone momentum k_v. We set up the holographic dictionary and compute 2-point functions of these operators both holographically and in field theory using conformal perturbation theory and find agreement. The counterterms needed for holographic renormalization are non-local in the v lightcone direction.

  13. Radiation carcinogenesis

    International Nuclear Information System (INIS)

    Studies on neutron carcinogenesis, time-dose relationships, the role of host factors in radiation carcinogenesis, and the dynamics of the carcinogenic process after exposure to radiation and chemicals are reported. Problems are being pursued with in vivo studies as well as in vitro and in vivo/in vitro approaches. A common theme among all of these studies is the examination of mechanisms and the establishment of general principles which may alow a better understanding of the risks to humans from radiation exposure. Data from all of these studies are also being used to examine more direct methods of extrapolation of animal data to human risks. The program in ultraviolet radiation carcinogenesis (UVR) is concerned with development of model systems, methods and background information necessary for designing quantitative UVR carcinogenesis experiments, the role of interactions of UVR and chemicals, and interactions between ionizing and ultraviolet radiation in skin carcinogenesis

  14. Alpha Background Rejection in Bolometer Detectors

    Science.gov (United States)

    Deporzio, Nicholas; Cuore Collaboration

    This study presents the modification of bolometer detectors used in particle searches to veto or otherwise reject alpha radiation background and the statistical advantages of doing so. Several techniques are presented in detail - plastic film scintillator vetoes, metallic film ionization vetoes, and Cherenkov radiation vetoes. Plastic scintillator films are cooled to bolometer temperatures and bombarded with 1.4MeV to 6.0MeV alpha particles representative of documented detector background. Quantum dot based liquid scintillator is similarly bombarded to produce a background induced scintillation light. Photomultipliers detect this scintillation light and produce a veto signal. Layered metallic films of a primary metal, dielectric, and secondary metal, such as gold-polyethylene-gold films, are cooled to milli-kelvin temperatures and biased to produce a current signal veto when incident 1.4MeV to 6.0MeV alpha particles ionize conduction paths through the film. Calibration of veto signal to background energy is presented. These findings are extrapolated to quantify the statistical impact of such modifications to bolometer searches. Effects of these techniques on experiment duration and signal-background ratio are discussed.

  15. Calibrating cosmological radiative transfer simulations with Lyman alpha forest data: Evidence for large spatial UV background fluctuations at z ~ 5.6 - 5.8 due to rare bright sources

    CERN Document Server

    Chardin, Jonathan; Aubert, Dominique; Puchwein, Ewald

    2015-01-01

    We calibrate here cosmological radiative transfer simulation with ATON/RAMSES with a range of measurements of the Lyman alpha opacity from QSO absorption spectra. We find the Lyman alpha opacity to be very sensitive to the exact timing of hydrogen reionisation. Models reproducing the measured evolution of the mean photoionisation rate and average mean free path reach overlap at z ~ 7 and predict an accelerated evolution of the Lyman alpha opacity at z > 6 consistent with the rapidly evolving luminosity function of Lyman alpha emitters in this redshift range. Similar to "optically thin" simulations our full radiative transfer simulations fail, however, to reproduce the high-opacity tail of the Lyman alpha opacity PDF at z > 5. We argue that this is due to spatial UV fluctuations in the post-overlap phase of reionisation on substantially larger scales than predicted by our source model, where the ionising emissivity is dominated by large numbers of sub-L* galaxies. We further argue that this suggests a signific...

  16. Genetical background of intelligence.

    Science.gov (United States)

    Junkiert-Czarnecka, Anna; Haus, Olga

    2016-01-01

    Intelligence as an ability to reason, think abstractly and adapt effectively to the environment is a subject of research in the field of psychology, neurobiology, and in the last twenty years genetics as well. Genetical testing of twins carried out from XX century indicated heritebility of intelligence, therefore confirmed an influence of genetic factor on cognitive processes. Studies on genetic background of intelligence focus on dopaminergic (DRD2, DRD4, COMT, SLC6A3, DAT1, CCKAR) and adrenergic system (ADRB2, CHRM2) genes as well as, neutrofins (BDNF) and oxidative stress genes (LTF, PRNP). Positive effect of investigated gene polymorphism was indicated by variation c.957C>T DRD2 gene (if in polymorphic site is thymine), polymorphism c.472G>A COMT gene (presence of adenine) and also gene ADRB2 c.46A->G (guanine), CHRM2 (thymine in place c.1890A>T) and BDNF (guanine in place c.472G>A) Obtained results indicate that intelligence is a feature dependent not only on genetic but also an environmental factor. PMID:27333929

  17. Biological aerosol background characterization

    Science.gov (United States)

    Blatny, Janet; Fountain, Augustus W., III

    2011-05-01

    To provide useful information during military operations, or as part of other security situations, a biological aerosol detector has to respond within seconds or minutes to an attack by virulent biological agents, and with low false alarms. Within this time frame, measuring virulence of a known microorganism is extremely difficult, especially if the microorganism is of unknown antigenic or nucleic acid properties. Measuring "live" characteristics of an organism directly is not generally an option, yet only viable organisms are potentially infectious. Fluorescence based instruments have been designed to optically determine if aerosol particles have viability characteristics. Still, such commercially available biological aerosol detection equipment needs to be improved for their use in military and civil applications. Air has an endogenous population of microorganisms that may interfere with alarm software technologies. To design robust algorithms, a comprehensive knowledge of the airborne biological background content is essential. For this reason, there is a need to study ambient live bacterial populations in as many locations as possible. Doing so will permit collection of data to define diverse biological characteristics that in turn can be used to fine tune alarm algorithms. To avoid false alarms, improving software technologies for biological detectors is a crucial feature requiring considerations of various parameters that can be applied to suppress alarm triggers. This NATO Task Group will aim for developing reference methods for monitoring biological aerosol characteristics to improve alarm algorithms for biological detection. Additionally, they will focus on developing reference standard methodology for monitoring biological aerosol characteristics to reduce false alarm rates.

  18. Low background infrared (LBIR) facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Low background infrared (LBIR) facility was originally designed to calibrate user supplied blackbody sources and to characterize low-background IR detectors and...

  19. Hanford Site background: Part 1, Soil background for nonradioactive analytes

    International Nuclear Information System (INIS)

    Volume two contains the following appendices: Description of soil sampling sites; sampling narrative; raw data soil background; background data analysis; sitewide background soil sampling plan; and use of soil background data for the detection of contamination at waste management unit on the Hanford Site

  20. Nonparametric Inference for the Cosmic Microwave Background

    CERN Document Server

    Genovese, C R; Nichol, R C; Arjunwadkar, M; Wasserman, L; Genovese, Christopher R.; Miller, Christopher J.; Nichol, Robert C.; Arjunwadkar, Mihir; Wasserman, Larry

    2004-01-01

    The Cosmic Microwave Background (CMB), which permeates the entire Universe, is the radiation left over from just 380,000 years after the Big Bang. On very large scales, the CMB radiation field is smooth and isotropic, but the existence of structure in the Universe - stars, galaxies, clusters of galaxies - suggests that the field should fluctuate on smaller scales. Recent observations, from the Cosmic Microwave Background Explorer to the Wilkinson Microwave Anisotropy Project, have strikingly confirmed this prediction. CMB fluctuations provide clues to the Universe's structure and composition shortly after the Big Bang that are critical for testing cosmological models. For example, CMB data can be used to determine what portion of the Universe is composed of ordinary matter versus the mysterious dark matter and dark energy. To this end, cosmologists usually summarize the fluctuations by the power spectrum, which gives the variance as a function of angular frequency. The spectrum's shape, and in particular the ...

  1. The cosmic mult-messenger background field

    Science.gov (United States)

    Hartmann, Dieter

    2016-04-01

    The cosmic star formation history associated with baryon flows within the large scale structure of the expanding Universe has many important consequences, such as cosmic chemical- and galaxy evolution. Stars and accreting compact objects subsequently produce light, from the radio band to the highest photon energies, and dust within galaxies reprocesses a significant fraction of this light into the IR region. The Universe creates a radiation background that adds to the relic field from the big bang, the CMB. In addition, Cosmic Rays are created on variouys scales, and interact with this diffuse radiation field, and neutrinos are added as well. A multi-messenger field is created whose evolution with redshift contains a tremendous amount of cosmological information. We discuss several aspects of this story, emphasizing the background in the HE regime and the neutrino sector, and disccus the use of gamma-ray sources as probes.

  2. Cosmic Background Explorer (COBE): Emergency support

    Science.gov (United States)

    Stanford, R.; Mattson, R.

    1991-01-01

    The Cosmic Background Explorer (COBE) Mission will measure the diffuse radiation from the universe in the wavelength band 1 micron to 9.6 mm. The band includes the 3 K cosmic background radiation, the known relic of the primeval cosmic explosion. The COBE satellite will be launched from the Western Space and Missile Center (EWSMC) via a Delta launch vehicle into a circular parking orbit of about 300 km. COBE will be placed into a 900-km altitude circular orbit. Coverage will be provided by the Deep Space Network (DSN) for COBE emergencies that would prevent communications via the normal channels of the Tracking and Data Relay Satellite System (TDRSS). Emergency support will be provided by the DSN 26-m subnetwork. Information is given in tabular form for DSN network support, frequency assignments, telemetry, and command.

  3. Dips in the Diffuse Supernova Neutrino Background

    OpenAIRE

    Farzan, Yasaman; Palomares-Ruiz, Sergio(Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, E-46071 Valencia, Spain)

    2014-01-01

    Scalar (fermion) dark matter with mass in the MeV range coupled to ordinary neutrinos and another fermion (scalar) is motivated by scenarios that establish a link between radiatively generated neutrino masses and the dark matter relic density. With such a coupling, cosmic supernova neutrinos, on their way to us, could resonantly interact with the background dark matter particles, giving rise to a dip in their redshift-integrated spectra. Current and future neutrino dete...

  4. Background stratified Poisson regression analysis of cohort data

    OpenAIRE

    Richardson, David B.; Langholz, Bryan

    2011-01-01

    Background stratified Poisson regression is an approach that has been used in the analysis of data derived from a variety of epidemiologically important studies of radiation-exposed populations, including uranium miners, nuclear industry workers, and atomic bomb survivors. We describe a novel approach to fit Poisson regression models that adjust for a set of covariates through background stratification while directly estimating the radiation-disease association of primary interest. The approa...

  5. The Yuan-Tseh Lee Array for Microwave Background Anisotropy

    OpenAIRE

    Ho, Paul T. P.; Altamirano, Pablo; Chang, Chia-Hao; Chang, Shu-Hao; Chang, Su-Wei; Chen, Chung-Cheng; Chen, Ke-Jung; Chen, Ming-Tang; Han, Chih-Chiang; Ho, West M.; Huang, Yau-De; Hwang, Yuh-Jing; Ibanez-Romano, Fabiola; Jiang, Homin; Koch, Patrick M.

    2008-01-01

    The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the first interferometer dedicated to studying the cosmic microwave background (CMB) radiation at 3mm wavelength. The choice of 3mm was made to minimize the contributions from foreground synchrotron radiation and Galactic dust emission. The initial configuration of seven 0.6m telescopes mounted on a 6-m hexapod platform was dedicated in October 2006 on Mauna Loa, Hawaii. Scientific operations began with the detection of a ...

  6. Supergravity backgrounds and symmetry superalgebras

    CERN Document Server

    Ertem, Ümit

    2016-01-01

    We consider the bosonic sectors of supergravity theories in ten and eleven dimensions which correspond to the low energy limits of string theories and M-theory. The solutions of supergravity field equations are known as supergravity backgrounds and the number of preserved supersymmetries in those backgrounds are determined by Killing spinors. We provide some examples of supergravity backgrounds which preserve different fractions of supersymmetry. An important invariant for the characterization of supergravity backgrounds is their Killing superalgebras which are constructed out of Killing vectors and Killing spinors of the background. After constructing Killing superalgebras of some special supergravity backgrounds, we discuss about the possibilities of the extensions of these superalgebras to include the higher degree hidden symmetries of the background.

  7. Some perspectives on radiation protection

    International Nuclear Information System (INIS)

    A brief review of the history and organizational structure of the NCRP is given. Summaries are given of a number of NCRP radiation protection guides dealing with hazards from 85Kr, radiation exposures from consumer products, basic radiation protection criteria, and doses from natural background radiation

  8. Background subtraction theory and practice

    CERN Document Server

    Elgammal, Ahmed

    2014-01-01

    Background subtraction is a widely used concept for detection of moving objects in videos. In the last two decades there has been a lot of development in designing algorithms for background subtraction, as well as wide use of these algorithms in various important applications, such as visual surveillance, sports video analysis, motion capture, etc. Various statistical approaches have been proposed to model scene backgrounds. The concept of background subtraction also has been extended to detect objects from videos captured from moving cameras. This book reviews the concept and practice of back

  9. Search for the Cosmic Neutrino Background

    International Nuclear Information System (INIS)

    One expects three Cosmic Backgrounds: (1) The Cosmic Microwave Background (CMB) originated 380000 years after the Big Bang (BB). (2) The Neutrino Background decoupled about one second after the BB, while (3) the Cosmic Gravitational Wave Background created by the inflationary expansion decoupled directly after the BB. Only the Cosmic Microwave Background (CMB) has been detected and is well studied. Its spectrum follows Planck's black body radiation formula and shows a remarkable constant temperature of T0γ ≈ 2.7 K independent of the direction. The present photon density is about 370 photons per cm3. The size of the hot spots, which deviates only in the fifth decimal of the temperature from the average value, tells us, that the universe is flat. About 380 000 years after the Big Bang at a temperature of T0γ = 3000 K already in the matter dominated era the electrons combine with the protons and 4He and the photons move freely in the neutral universe and form the CMB. So the temperature and distribution of the photons give us information of the universe 380 000 years after the Big Bang. The Cosmic Neutrino Background (CνB) decoupled from matter already one second after the BB at a temperature of about 1010 K. Today their temperature is ∼ 1.95 K and the average density is 56 electron-neutrinos and the total density of all neutrinos about 336 per cm3. Measurement of these neutrinos is an extremely challenging experimental problem which can hardly be solved with the present technologies. On the other hand it represents a tempting opportunity to check one of the key elements of the Big Bang Cosmology and to probe the early stages of the universe. The search for the CνB with the induced beta decay νe+3H → 3He + e− using KATRIN (KArlsruhe TRItium Neutrino experiment) is the topic of this contribution

  10. Alpha Background Rejection in Bolometer Detectors

    Science.gov (United States)

    Deporzio, Nicholas

    2016-03-01

    This study presents the modification of bolometer detectors used in particle searches to veto or otherwise reject alpha radiation background and the statistical advantages of doing so. Several techniques are presented in detail - plastic film scintillator vetoes, metallic film ionization vetoes, and scintillating bolometer vetoes. Plastic scintillator films are cooled to bolometer temperatures and bombarded with 1.4MeV to 6.0MeV alpha particles representative of documented detector background. Photomultipliers detect this scintillation light and produce a veto signal. Layered metallic films of a primary metal, dielectric, and secondary metal, such as gold-polyethylene-gold films, are cooled to milli-kelvin temperatures and biased to produce a current signal veto when incident 1.4MeV to 6.0MeV alpha particles ionize conduction paths through the film. Modified Zinc Molybdate Bolometers are used to produce scintillation light when stimulated by alpha background. Calibration of veto signal to background energy is presented. Results are used to quantify the statistical impact of such modifications on bolometer searches.

  11. Hanford Site background: Part 1, Soil background for nonradioactive analytes

    International Nuclear Information System (INIS)

    The determination of soil background is one of the most important activities supporting environmental restoration and waste management on the Hanford Site. Background compositions serve as the basis for identifying soil contamination, and also as a baseline in risk assessment processes used to determine soil cleanup and treatment levels. These uses of soil background require an understanding of the extent to which analytes of concern occur naturally in the soils. This report documents the results of sampling and analysis activities designed to characterize the composition of soil background at the Hanford Site, and to evaluate the feasibility for use as Sitewide background. The compositions of naturally occurring soils in the vadose Zone have been-determined for-nonradioactive inorganic and organic analytes and related physical properties. These results confirm that a Sitewide approach to the characterization of soil background is technically sound and is a viable alternative to the determination and use of numerous local or area backgrounds that yield inconsistent definitions of contamination. Sitewide soil background consists of several types of data and is appropriate for use in identifying contamination in all soils in the vadose zone on the Hanford Site. The natural concentrations of nearly every inorganic analyte extend to levels that exceed calculated health-based cleanup limits. The levels of most inorganic analytes, however, are well below these health-based limits. The highest measured background concentrations occur in three volumetrically minor soil types, the most important of which are topsoils adjacent to the Columbia River that are rich in organic carbon. No organic analyte levels above detection were found in any of the soil samples

  12. Background reduction in cryogenic detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Daniel A.; /Fermilab

    2005-04-01

    This paper discusses the background reduction and rejection strategy of the Cryogenic Dark Matter Search (CDMS) experiment. Recent measurements of background levels from CDMS II at Soudan are presented, along with estimates for future improvements in sensitivity expected for a proposed SuperCDMS experiment at SNOLAB.

  13. Children of ethnic minority backgrounds

    DEFF Research Database (Denmark)

    Johansen, Stine Liv

    2010-01-01

    Children of ethnic minority background balance their everyday life between a cultural background rooted in their ethnic origin and a daily life in day care, schools and with peers that is founded in a majority culture. This means, among other things, that they often will have access to different ...

  14. Background compensation methodologies for contamination monitoring systems

    International Nuclear Information System (INIS)

    Radiation surveillance program in the various nuclear facilities incorporate contamination monitoring as an important component. Contamination monitoring programs constitute monitoring for alpha and beta contamination of the physical entities associated with the working personnel that include his hands, feet, clothing, shoes as well as the general surface areas in the working environment like floors. All these measurements are fraught with the contribution of the ambient gamma background radiation fields. These inhibit a proper and precise estimation of the contamination concentration being monitored. This paper investigates the efficacy of two methodologies that have been incorporated in two of the contamination monitoring systems developed in the Division. In the first system discussed, a high degree of gamma compensation has been achieved for an uniform exposure of the order of 50 nSv/hr to 100 mSv/hr. In the second system discussed, the degree of gamma compensation achieved is equal to those dictated by the statistical nature of the uncertainties associated with the subtraction of background from the source data. These two methods can be very effectively employed depending on the application requirement. A minimum detection level equivalent to 0.37 Bq/cdm2 has been achieved in both these cases

  15. Primordial Gravitational Waves and Cosmic Microwave Background Radiation

    CERN Document Server

    Baskaran, D; Zhao, W

    2010-01-01

    This is a summary of presentations delivered at the OC1 parallel session "Primordial Gravitational Waves and the CMB" of the 12th Marcel Grossmann meeting in Paris, July 2009. The reports and discussions demonstrated significant progress that was achieved in theory and observations. It appears that the existing data provide some indications of the presence of gravitational wave contribution to the CMB anisotropies, while ongoing and planned observational efforts are likely to convert these indications into more confident statements about the actual detection.

  16. Aspects Of Cosmic Inflation And Microwave Background Radiation

    CERN Document Server

    Kadota, K

    2004-01-01

    While the concepts of cosmic inflation have survived for more than two decades, we still do not know how inflation was triggered and how our universe evolved since then. The main theme of this thesis is to present some attempts at building and testing realistic inflationary cosmology scenarios. For building of inflation models, we place an emphasis on high energy particle theory which most likely governs the dynamics in the early universe. For testing of inflation, we give detailed account on the cosmic perturbation theory in view of current/future CMB data.

  17. Division G Commission 21: Galactic and Extragalactic Backgrounds Radiation

    Science.gov (United States)

    Murthy, Jayant; Witt, Adolf; Baggaley, W. Jack; Dwek, Eli; Levasseur-Regourd, Anny-Chantal; Mann, Ingrid; Mattila, Kalevi; Watanabe, Jun-Ichi

    2016-04-01

    Commission 21 was one of the oldest and smallest in the IAU yet one which underwent the most evolution since its inception. It began in 1955 as Light of the Night Sky (Lumière du Ciel Nocturne) under the Presidentship of Jean Dufay (University Observatory at Lyon). As the name suggested, in the years before space observations, its focus was on observations of atmospheric light which, at the time, was the domain of astronomers. Thus the early proceedings of the Commission were dominated by reports of the daytime and nighttime emission as observed from different locations and different conditions. Our knowledge of the Earth's atmosphere is still shaped by these early observations (Meier R.R., 1991, Space Sci. Rev. 58, 1). Members of Commission 21 were key to organizing interational collaborations to set up atmospheric stations at different latitudes, including in the Souther hemisphere and in ensuring a consistent calibration between the instruments. The Commission also bought in results from Soviet scientists in an era where communication was limited by both politics and language.

  18. Upper Limits on a Stochastic Background of Gravitational Waves

    OpenAIRE

    Abbott, B.; Abbott, R.; Adhikari, R.; Agresti, J.; Ajith, P.; Allen, B.; Allen, J; R. Amin; Anderson, S; Anderson, W.; Araya, M; Armandula, H.; Ashley, M.; Aulbert, C.; Babak, S

    2005-01-01

    The Laser Interferometer Gravitational Wave Observatory (LIGO) has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of Omega_0

  19. Generalized Background-Field Method

    CERN Document Server

    Feng, Y J

    1997-01-01

    The graphical method discussed previously can be used to create new gauges not reachable by the path-integral formalism. By this means a new gauge is designed for more efficient two-loop QCD calculations. It is related to but simpler than the ordinary background-field gauge, in that even the triple-gluon vertices for internal lines contain only four terms, not the usual six. This reduction simplifies the calculation inspite of the necessity to include other vertices for compensation. Like the ordinary background-field gauge, this generalized background-field gauge also preserves gauge invariance of the external particles. As a check of the result and an illustration for the reduction in labour, an explicit calculation of the two-loop QCD 45% of computation compared to the ordinary background-field gauge.

  20. Geometrodynamics on a background spacetime

    CERN Document Server

    Papadopoulos, P P; Papadopoulos, Philippos; Sopuerta, Carlos F.

    2001-01-01

    The formulation of the initial value problem for the Einstein equations is at the heart of obtaining interesting new solutions using numerical relativity and still very much under theoretical and applied scrutiny. We develop a specialised background geometry approach, for systems where there is non-trivial a priori knowledge about the spacetime under study. The background three-geometry and associated connection are used to express the ADM evolution equations in terms of physical non-linear deviations from that background. Expressing the equations in first order form leads naturally to a system closely linked to the Einstein-Christoffel system, introduced by Anderson and York, and sharing its hyperbolicity properties. The background metric approach can drastically alter the source structure of the equations, and we present an argument as to why this is likely to be numerically advantageous.

  1. Radiation in daily life

    International Nuclear Information System (INIS)

    The medical community benefits on a daily basis from the ionizing radiations used in the diagnosis and treatment of disease. The doses received in the medical field are only a small fraction of the total radiation received in a year. This bibliographic review has several objectives. The first one is to present the different components of natural radiation (background radiation). Secondly, it will introduce many consumer products that contain radioactive sources and expose our bodies. Third, arguments to diminish the radiation phobia will be presented and finally an easy to understand dosimetric magnitude will be introduced for the physician, the technologist and the patient. (author)

  2. QED_2 in Curved Backgrounds

    OpenAIRE

    Ghosh, Amit

    1996-01-01

    Here we discuss the two dimensional quantum electrodynamics in curved space-time, especially in the background of some black holes. We first show the existence of some new quantum mechanical solution which has interesting properties. Then for some special black holes we discuss the fermion-black hole scattering problem. The issue of confinement is intimately connected with these solutions and we also comment on this in this background. Finally, the entanglement entropy and the Hawking radiati...

  3. Backgrounds in AFP Detector Estimation

    CERN Document Server

    Huang, Yicong

    2016-01-01

    The ATLAS Forward Proton (AFP) detectors aim to measure protons that are scattered in the ATLAS interaction point under very small angles ($90-160 \\mu rad$). The diffractive protons detected by the AFP may be accompanied by beam halo. This report presents an estimation of the beam halo backgrounds in the AFP using low pile-up data, and position distributions of the backgrounds in the AFP.

  4. The Supernova Relic Neutrino Background

    OpenAIRE

    Kaplinghat, M.; Steigman, G.; Walker, T. P.

    1999-01-01

    An upper bound to the supernova relic neutrino background from all past Type II supernovae is obtained using observations of the Universal metal enrichment history. We show that an unambiguous detection of these relic neutrinos by the Super-Kamiokande detector is unlikely. We also analyze the event rate in the Sudbury Neutrino Observatory (where coincident neutrons from anti-nu_e + D --> n + n + e+ might enhance background rejection), and arrive at the same conclusion. If the relic neutrino f...

  5. Simulation of PEP-II Accelerator Backgrounds Using TURTLE

    International Nuclear Information System (INIS)

    We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using LPTURTLE, a modified version of the DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremsstrahlung, beam-gas Coulomb scattering, radiative- Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full programme of beam gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modeling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails

  6. Simulation of PEP-II Accelerator Backgrounds Using TURTLE

    CERN Document Server

    Barlow, Roger J; Kozanecki, Witold; Majewski, Stephanie; Roudeau, Patrick; Stocchi, Achille

    2005-01-01

    We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using a modified version ofthe DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full programme of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modelling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.

  7. Radiation in genetic engineering

    International Nuclear Information System (INIS)

    Radiation as used in genetic engineering involves producing changes in the hereditary units of existing plants and animals by the use of radiation. The desired results of such irradiation is to increase the quality and/or quantity of such plants or animals. The mode of radiation interaction with biological samples or cells is described by the 'Target theory'. This theory considers the radiosensitive portion of the medium as target to be hit by radiation particles. Cellular effect of radiation can be divided into two types, i.e. effect on cell division and effects on cell metabolism. As a result of radiation induced changes to DNA and proteins, visible damage to chromosome can sometimes be seen. Every radiation, even a single beta particle may be of great importance and consequence if it hits a vital component in a particular manner. Hence even normal background radiation induces mutation and may help in the natural evolution process. (A.S.)

  8. Background analysis and comparison of two solid food markers (DTPA and HSA) in the measurement of human gastric emptying

    International Nuclear Information System (INIS)

    The measurement of gastric emptying of radiolabelled solid food is described. A procedure enabling the assessment of background radiation, and connected with it corrections of the parameters characterizing gastric emptying curves are discussed in detail. Considering background radiation, /sup 99m/Tc/labelled DTPA and HSA are shown to be equivalent as solid meal markers in studying gastric emptying. Corrections for background radiation can be neglected, if the background to total count ratio has been sufficiently reduced. (author)

  9. Environmental radiation data, 9

    International Nuclear Information System (INIS)

    The Environmental Physics Laboratory has conducted a large number of background radiation surveys in these years, aiming at the analysis of characteristics and behaviour of environmental radiation, the development of measurement techniques and instruments of environmental radiation, and the evaluation of environmental radiation dose. As the environmental radiation data obtained by these surveys are useful for broad purposes as actual survey data, it is desirable to arrange these data systematically and to open them to the other scientist. For that, it is necessary to make the recording media and the FORMAT of these data available for usual computers. In the light of this circumstance, these data were rearranged and recompiled systematically to meet the demand. This report mentions about the data obtained by the background radiation surveys in and around Tokyo performed during 1991 - 1993 using portable instruments, as well as the information necessary for the data handling. (author)

  10. Improvements to background level of the low background HPGe setup

    International Nuclear Information System (INIS)

    A low background HPGe counting setup has been installed at TIFR. The detector, shielded with low activity Pb and Cu shield, has been extensively used for material screening for the TIN. TIN detector (The INdia-based TIN detector). It is proposed to use this setup for the search of rare decay processes like double beta decay (DBD) to the excited states of the daughter nuclei where T1/2 > 1018 years. To enhance the sensitivity of measurement, the background levels of the detector has been further improved by an addition of an active cosmic muon veto system in the FPGA based DAQ system

  11. On the Geometry of Background Currents in General Relativity

    Directory of Open Access Journals (Sweden)

    Suhendro I.

    2015-12-01

    Full Text Available In this preliminary work, we shall reveal the intrinsic geometry of background currents, possibly of electromagnetic origin, in the space-time of General Relativity. Drawing a close analogy between the object of our present study and electromagnetism, we shall show that there exists an inherent, fully non-linear, conservative third-rank radiation current which is responsible for the irregularity in the curvature of the background space(-time, whose potential (generator is of purely geometric origin.

  12. Progress in Understanding the Diffuse UV Cosmic Background

    OpenAIRE

    Henry, Richard Conn

    2012-01-01

    I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet spectrometer observations of the diffuse background shortward of Lyman alpha, including for the first time measurements made from the outermost regions of the solar system, where noise from solar-system scattered (and then grating-scattered) solar Lyman alpha is ...

  13. The cosmic microwave background: past, present and future

    International Nuclear Information System (INIS)

    The cosmic microwave background has provided an unprecedented cosmological window on the very early universe for probing the initial conditions from which structure evolved. Infinitesimal variations in temperature on the sky, first predicted in 1967 but only discovered in the 1990s, provide the fossil fluctuations that seeded the formation of the galaxies. The cosmic microwave background radiation has now been mapped with ground-based, balloon-borne and satellite telescopes. I describe its current status and future challenges

  14. A definition of background independence

    International Nuclear Information System (INIS)

    We propose a definition for background (in)/dependence in dynamical theories of the evolution of configurations that have a continuous symmetry and test this definition on particle models and on gravity. Our definition draws from Barbour's best matching framework developed for the purpose of implementing spatial and temporal relationalism. Among other interesting theories, general relativity can be derived within this framework in novel ways. We study the detailed canonical structure of a wide range of best matching theories and show that their actions must have a local gauge symmetry. When gauge theory is derived in this way, we obtain at the same time a conceptual framework for distinguishing between background-dependent and -independent theories. Gauge invariant observables satisfying Kuchar's criterion are identified and, in simple cases, explicitly computed. We propose a procedure for inserting a global background time into temporally relational theories. Interestingly, using this procedure in general relativity leads to unimodular gravity.

  15. Neutron background estimates in GESA

    Directory of Open Access Journals (Sweden)

    Fernandes A.C.

    2014-01-01

    Full Text Available The SIMPLE project looks for nuclear recoil events generated by rare dark matter scattering interactions. Nuclear recoils are also produced by more prevalent cosmogenic neutron interactions. While the rock overburden shields against (μ,n neutrons to below 10−8 cm−2 s−1, it itself contributes via radio-impurities. Additional shielding of these is similar, both suppressing and contributing neutrons. We report on the Monte Carlo (MCNP estimation of the on-detector neutron backgrounds for the SIMPLE experiment located in the GESA facility of the Laboratoire Souterrain à Bas Bruit, and its use in defining additional shielding for measurements which have led to a reduction in the extrinsic neutron background to ∼ 5 × 10−3 evts/kgd. The calculated event rate induced by the neutron background is ∼ 0,3 evts/kgd, with a dominant contribution from the detector container.

  16. Generative electronic background music system

    Energy Technology Data Exchange (ETDEWEB)

    Mazurowski, Lukasz [Faculty of Computer Science, West Pomeranian University of Technology in Szczecin, Zolnierska Street 49, Szczecin, PL (Poland)

    2015-03-10

    In this short paper-extended abstract the new approach to generation of electronic background music has been presented. The Generative Electronic Background Music System (GEBMS) has been located between other related approaches within the musical algorithm positioning framework proposed by Woller et al. The music composition process is performed by a number of mini-models parameterized by further described properties. The mini-models generate fragments of musical patterns used in output composition. Musical pattern and output generation are controlled by container for the mini-models - a host-model. General mechanism has been presented including the example of the synthesized output compositions.

  17. Detector Background at Muon Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Mokhov, N.V.; Striganov, S.I.; /Fermilab

    2011-09-01

    Physics goals of a Muon Collider (MC) can only be reached with appropriate design of the ring, interaction region (IR), high-field superconducting magnets, machine-detector interface (MDI) and detector. Results of the most recent realistic simulation studies are presented for a 1.5-TeV MC. It is shown that appropriately designed IR and MDI with sophisticated shielding in the detector have a potential to substantially suppress the background rates in the MC detector. The main characteristics of backgrounds are studied.

  18. Background music and cognitive performance.

    Science.gov (United States)

    Angel, Leslie A; Polzella, Donald J; Elvers, Greg C

    2010-06-01

    The present experiment employed standardized test batteries to assess the effects of fast-tempo music on cognitive performance among 56 male and female university students. A linguistic processing task and a spatial processing task were selected from the Criterion Task Set developed to assess verbal and nonverbal performance. Ten excerpts from Mozart's music matched for tempo were selected. Background music increased the speed of spatial processing and the accuracy of linguistic processing. The findings suggest that background music can have predictable effects on cognitive performance. PMID:20865993

  19. Exotic branes and nongeometric backgrounds.

    Science.gov (United States)

    de Boer, Jan; Shigemori, Masaki

    2010-06-25

    When string or M theory is compactified to lower dimensions, the U-duality symmetry predicts so-called exotic branes whose higher-dimensional origin cannot be explained by the standard string or M-theory branes. We argue that exotic branes can be understood in higher dimensions as nongeometric backgrounds or U folds, and that they are important for the physics of systems which originally contain no exotic charges, since the supertube effect generically produces such exotic charges. We discuss the implications of exotic backgrounds for black hole microstate (non-)geometries. PMID:20867363

  20. Generative electronic background music system

    International Nuclear Information System (INIS)

    In this short paper-extended abstract the new approach to generation of electronic background music has been presented. The Generative Electronic Background Music System (GEBMS) has been located between other related approaches within the musical algorithm positioning framework proposed by Woller et al. The music composition process is performed by a number of mini-models parameterized by further described properties. The mini-models generate fragments of musical patterns used in output composition. Musical pattern and output generation are controlled by container for the mini-models - a host-model. General mechanism has been presented including the example of the synthesized output compositions

  1. High efficiency neutron spectrometer with low background

    International Nuclear Information System (INIS)

    A neutron energy spectrometer with a geometry close to 4π solid angle operated in the (1-5) MeV energy range at a suitable for a cold fusion experiment configuration and a very good n/γ discrimination, has been constructed. Tests of registration efficiency, energy resolution and radiation type identification have been made with a help of low intensity neutron and gamma sources. The spectrometer has shown the efficiency of about 10% at the 2x10-3s-1 background level and permits one to measure a neutron energy spectrum at a very low intensity of the source. Physical principles, design of the neutron detector system and results of its testing are described. 6 refs.; 6 figs.; 1 tab

  2. Anomalies of the Cosmic Microwave Background

    DEFF Research Database (Denmark)

    Hansen, Martin Anders Kirstejn

    The Cosmic Microwave Background (CMB) is the faint afterglow of the extreme conditions that existed shortly after Big Bang. The temperature of the CMB radiation across the sky is extremely uniform, yet tiny anisotropies are present, and have with recent satellite missions been mapped to very high...... with the parity asymmetry. A brief set of results for the parity asymmetry for the 4 data sets from the Planck satellite. This is compared with simulations to show how anomalous the observed low value of the parity asymmetry is. A test devoted to investigating whether the Edgeworth-Kuiper belt can aect...... for modern Cosmology. Ever since the first easurements of the CMB anisotropy, several anomalies have been reported, and subsequently confirmed by later satellite, ground and balloon based missions. These anomalies does not conform to the standard model of cosmic inflation, and may thereby jeopardize...

  3. Background deduction method based on inverse square law

    International Nuclear Information System (INIS)

    Based on the inverse square dependence of neutron signal amplitude on the distance between neutron detector and neutron source, a new method is suggested for radiation scattering background deduction in sensitivity calibration experiment for current-mode neutron detectors. Using this method, the traditional collimators and shielding materials are not necessary anymore. As the scattering background typically does not vary with the distance in the same way as the signal, a series of current can be measured at different positions and then analyses can be conducted, which give not only the sensitivity of the detector, but also background distributions at various positions. (authors)

  4. Low Background Micromegas in CAST

    CERN Document Server

    Garza, J G; Aznar, F.; Calvet, D.; Castel, J.F.; Christensen, F.E.; Dafni, T.; Davenport, M.; Decker, T.; Ferrer-Ribas, E.; Galán, J.; García, J.A.; Giomataris, I.; Hill, R.M.; Iguaz, F.J.; Irastorza, I.G.; Jakobsen, A.C.; Jourde, D.; Mirallas, H.; Ortega, I.; Papaevangelou, T.; Pivovaroff, M.J.; Ruz, J.; Tomás, A.; Vafeiadis, T.; Vogel, J.K.

    2015-01-01

    Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micromegas detectors for the CERN Axion Solar Telescope (CAST), including technological pathfinder activities for the future International Axion Observatory (IAXO). The use of low background techniques and the application of discrimination algorithms based on the high granularity of the readout have led to background levels below 10$^{-6}$ counts/keV/cm$^2$/s, more than a factor 100 lower than the first generation of Micromegas detectors. The best levels achieved at the Canfranc Underground Laboratory (LSC) are as low as 10$^{-7}$ counts/keV/cm$^2$/s, showing good prospects for the application of this technology in IAXO. The current background model, based on underground and surface measurements, is presented, as well as ...

  5. Low Background Micromegas in CAST

    DEFF Research Database (Denmark)

    Garza, J G; Aune, S.; Aznar, F.;

    2014-01-01

    Solar axions could be converted into x-rays inside the strong magnetic field of an axion helioscope, triggering the detection of this elusive particle. Low background x-ray detectors are an essential component for the sensitivity of these searches. We report on the latest developments of the Micr...

  6. Low background techniques in CANDLES

    International Nuclear Information System (INIS)

    CANDLES is a double beta decay experiment using 48Ca in CaF2 crystals. The measurement is being performed with prototype detector (CANDLES III) for high sensitive measurement in the future. Recent status of detector improvements and background reduction techniques are described in this paper

  7. Radiation effects and radiation risks

    International Nuclear Information System (INIS)

    The book presents the facts and the principles of assessment and evaluation of biological radiation effects in general and also with particular reference to the reactor accident of Chernobyl, reviewing the consequences and the environmental situation on the basis of current national and international literature, including research work by the authors. The material compiled in this book is intended especially for physicians, but will also prove useful for persons working in the public health services, in administration, or other services taking care of people. The authors tried to find an easily comprehensible way of presenting and explaining the very complex processes and mechanisms of biological radiation effects and carcinogenesis, displaying the physical primary processes and the mechanisms of the molecular radiation effects up to the effects of low-level radiation, and present results of comparative epidemiologic studies. This section has been given considerable space, in proportion to its significance. It also contains literature references for further reading, offering more insight and knowledge of aspects of special subject fields. The authors also present less known results and data and discuss them against the background of well-known research results and approaches. Apart from the purpose of presenting comprehensive information, the authors intend to give an impact for further thinking about the problems, and helpful tools for independent decisions and action on the basis of improved insight and assessment, and in this context particularly point to the problems induced by the Chernobyl reactor accident. (orig./MG) With 8 maps in appendix

  8. The large scale microwave background anisotropy in decaying particle cosmology

    International Nuclear Information System (INIS)

    We investigate the large-scale anisotropy of the microwave background radiation in cosmological models with decaying particles. The observed value of the quadrupole moment combined with other constraints gives an upper limit on the redshift of the decay z/sub d/ < 3-5. 12 refs., 2 figs

  9. GammaSense: Infrastructureless Positioning using Background Radioactivity

    DEFF Research Database (Denmark)

    Bucur, Doina; Kjærgaard, Mikkel Baun

    2008-01-01

    We introduce the harvesting of natural background radioactivity for positioning. Using a standard Geiger-Müller counter as sensor, we fingerprint the natural levels of gamma radiation with the aim of then roughly pinpointing the position of a client in terms of interfloor, intrafloor, and indoor...

  10. Low-background β count and α spectrum measuring instrument

    International Nuclear Information System (INIS)

    An low-background β count and α spectrum measuring instrument which is used to ocean radiation investigation is introduced in this paper. It capable of simultaneously measure low activity β count and analyse α spectrum. Overcome by using two sets of Instrument were measured β count and α spectrum of trouble, and reduce the measurement error. (authors)

  11. Preliminary background prediction for the INTEGRAL x-ray monitor

    DEFF Research Database (Denmark)

    Feroci, M.; Costa, E.; Budtz-Joergensen, C.;

    1996-01-01

    The JEM-X (joint European x-ray monitor) experiment will be flown onboard the ESA's INTEGRAL satellite. The instrumental background level of the two JEM-X twin detectors will depend on several parameters, among which the satellite orbit and mass distribution, and the detectors materials play a...... major role. Based on the information available at the present stage of the emission design, we have computed the instrumental background to be expected because of two main background components: direct diffuse x-ray background and secondary photons originated by the interactions of the primary cosmic...... satellite structure is only now being completely defined and the details of the instrument design are still under evolution. The present background estimation can therefore be only preliminary and based on some reasonable approximations on the radiation environment in which the INTEGRAL experiments will...

  12. Cosmology on Compact and Stable Supergravity Background

    CERN Document Server

    Hailu, Girma

    2012-01-01

    We propose a cosmological model of D3-brane universe on compact and stable supergravity background of wrapped D7-branes in type IIB string theory previously argued to be dual to pure N=1 SU(N) gauge theory in four dimensions. A model universe of order Planck size near the UV boundary dynamically flows toward the IR with constant total energy density and accelerating expansion followed by smooth transition to decelerating expansion and collides with the wrapped D7-branes at the IR boundary. The model addresses the horizon and flatness problems with most of the expansion produced during the decelerating expansion phase. The inflationary scenario is used to generate sources of inhomogeneities in the cosmic microwave background radiation and seeds for large scale structure formation from quantum fluctuations which exit the Hubble radius early during the accelerating expansion phase and the model addresses the inhomogeneity problem with red tilt in the power spectrum. We propose that the kinetic energy of the mode...

  13. The Diffuse Supernova Neutrino Background

    CERN Document Server

    Beacom, John F

    2010-01-01

    The Diffuse Supernova Neutrino Background (DSNB) is the weak glow of MeV neutrinos and antineutrinos from distant core-collapse supernovae. The DSNB has not been detected yet, but the Super-Kamiokande (SK) 2003 upper limit on the electron antineutrino flux is close to predictions, now quite precise, based on astrophysical data. If SK is modified with dissolved gadolinium to reduce detector backgrounds and increase the energy range for analysis, then it should detect the DSNB at a rate of a few events per year, providing a new probe of supernova neutrino emission and the cosmic core-collapse rate. If the DSNB is not detected, then new physics will be required. Neutrino astronomy, while uniquely powerful, has proven extremely difficult -- only the Sun and the nearby Supernova 1987A have been detected to date -- so the promise of detecting new sources soon is exciting indeed.

  14. Stealths on Anisotropic Holographic Backgrounds

    CERN Document Server

    Ayón-Beato, Eloy; Juárez-Aubry, María Montserrat

    2015-01-01

    In this paper, we are interested in exploring the existence of stealth configurations on anisotropic backgrounds playing a prominent role in the non-relativistic version of the gauge/gravity correspondence. By stealth configuration, we mean a nontrivial scalar field nonminimally coupled to gravity whose energy-momentum tensor evaluated on the anisotropic background vanishes identically. In the case of a Lifshitz spacetime with a nontrivial dynamical exponent z, we spotlight the role played by the anisotropy to establish the holographic character of the stealth configurations, i.e. the scalar field is shown to only depend on the radial holographic direction. This configuration which turns out to be massless and without integration constants is possible for a unique value of the nonminimal coupling parameter. Then, using a simple conformal argument, we map this configuration into a stealth solution defined on the so-called hyperscaling violation metric which is conformally related to the Lifshitz spacetime. Thi...

  15. Background paper on aquaculture research

    OpenAIRE

    Wenblad, Axel; Jokumsen, Alfred; Eskelinen, Unto; Torrissen, Ole

    2013-01-01

    The Board of MISTRA established in 2012 a Working Group (WG) on Aquaculture to provide the Board with background information for its upcoming decision on whether the foundation should invest in aquaculture research. The WG included Senior Advisor Axel Wenblad, Sweden (Chairman), Professor Ole Torrissen, Norway, Senior Advisory Scientist Unto Eskelinen, Finland and Senior Advisory Scientist Alfred Jokumsen, Denmark. The WG performed an investigation of the Swedish aquaculture sector including ...

  16. Background radioactivity in environmental materials

    International Nuclear Information System (INIS)

    This paper presents the results of a literature search to identify information on concentrations of 'background' radioactivity in foodstuffs and other commonly available environmental materials. The review has concentrated on naturally occurring radioactivity in foods and on UK data, although results from other countries have also been considered where appropriate. The data are compared with established definitions of a 'radioactive' substance and radionuclides which do not appear to be adequately covered in the literature are noted. (author)

  17. Stochastic background of gravitational waves

    CERN Document Server

    D'Araújo, J C N; Aguiar, O D

    2000-01-01

    A continuous stochastic background of gravitational waves (GWs) for burst sources is produced if the mean time interval between the occurrence of bursts is smaller than the average time duration of a single burst at the emission, i.e., the so called duty cycle must be greater than one. To evaluate the background of GWs produced by an ensemble of sources, during their formation, for example, one needs to know the average energy flux emitted during the formation of a single object and the formation rate of such objects as well. In many cases the energy flux emitted during an event of production of GWs is not known in detail, only characteristic values for the dimensionless amplitude and frequencies are known. Here we present a shortcut to calculate stochastic backgrounds of GWs produced from cosmological sources. For this approach it is not necessary to know in detail the energy flux emitted at each frequency. Knowing the characteristic values for the ``lumped'' dimensionless amplitude and frequency we show tha...

  18. Background independence in a background dependent renormalization group

    Science.gov (United States)

    Labus, Peter; Morris, Tim R.; Slade, Zöe H.

    2016-07-01

    Within the derivative expansion of conformally reduced gravity, the modified split Ward identities are shown to be compatible with the flow equations if and only if either the anomalous dimension vanishes or the cutoff profile is chosen to have a power-law form. No solutions exist if the Ward identities are incompatible. In the compatible case, a clear reason is found for why Ward identities can still forbid the existence of fixed points; however, for any cutoff profile, a background independent (and parametrization independent) flow equation is uncovered. Finally, expanding in vertices, the combined equations are shown generically to become either overconstrained or highly redundant beyond the six-point level.

  19. Background independence in a background dependent renormalization group

    CERN Document Server

    Labus, Peter; Slade, Zoë H

    2016-01-01

    Within the derivative expansion of conformally reduced gravity, the modified split Ward identities are shown to be compatible with the flow equations if and only if either the anomalous dimension vanishes or the cutoff profile is chosen to be power law. No solutions exist if the Ward identities are incompatible. In the compatible case, a clear reason is found for why Ward identities can still forbid the existence of fixed points; however, for any cutoff profile, a background independent (and parametrisation independent) flow equation is uncovered. Finally, expanding in vertices, the combined equations are shown generically to become either over-constrained or highly redundant beyond the six-point level.

  20. Extracting the cosmic history from diffuse backgrounds

    Science.gov (United States)

    Pritchard, Jonathan Robin

    The modern picture of the Universe resembles a detective novel with the first page and the middle chapters removed and the ending unwritten. Observations of the cosmic microwave background (CMB) have given cosmologists a snapshot of the Universe when it was only a few hundred thousand years old. At the same time, large galaxy surveys, such as SDSS and 2dF, have shed light on the distribution of matter in the local Universe. From the combination of these two data sets, cosmological parameters can be measured to percent accuracy. Two main frontiers remain: inflation, the domain of high-energy physics, and the epoch of reionization, the period connecting the linear age of the CMB with that of the present day. Added to this are the indications from supernovae of an acceleration in the expansion rate suggesting modifications to gravity or the presence of an esoteric new form of energy.In this work, we investigate uses of various radiation backgrounds for probing the different epochs of this cosmic history. We examine (i) the use of B-mode polarization of the CMB induced by an inflationary gravitational wave background to probe inflation, (ii) the importance of higher Lyman series photons in pumping of the 21 cm line and the consequences for the 21 cm signal from the first stars, (iii) the atomic physics of Lyman series photon scattering in the intergalactic medium and the consequences for heating and coupling of the 21 cm line, (iv) the possibility of using the 21 cm line to probe inhomogeneous X-ray heating of the IGM by a population of early X-ray sources, and (v) the impact of inhomogeneous reionization on galaxy formation and the consequences for our ability to use large galaxy surveys to constrain dark energy. Together, these chapters significantly extend our understanding of important windows into the early Universe.

  1. The Anisotropy of the Microwave Background to l = 3500 Mosaic Observations with the Cosmic Background Imager

    CERN Document Server

    Pearson, T J; Readhead, A C S; Shepherd, M C; Sievers, J L; Udomprasert, P S; Cartwright, J K; Farmer, A J; Padin, S; Myers, S T; Bond, J R; Contaldi, C R; Pen, U L; Prunet, S; Pogosyan, D; Carlstrom, J E; Kovács, J; Leitch, E M; Pryke, C L; Halverson, N W; Holzapfel, W L; Altamirano, P; Bronfman, L; Casassus, S; May, J; Joy, M

    2003-01-01

    Using the Cosmic Background Imager, a 13-element interferometer array operating in the 26-36 GHz frequency band, we have observed 40 sq deg of sky in three pairs of fields, each ~ 145 x 165 arcmin, using overlapping pointings (mosaicing). We present images and power spectra of the cosmic microwave background radiation in these mosaic fields. We remove ground radiation and other low-level contaminating signals by differencing matched observations of the fields in each pair. The primary foreground contamination is due to point sources (radio galaxies and quasars). We have subtracted the strongest sources from the data using higher-resolution measurements, and we have projected out the response to other sources of known position in the power-spectrum analysis. The images show features on scales ~ 6 - 15 arcmin, corresponding to masses ~ (5 - 80)*10^{14} Msun at the surface of last scattering, which are likely to be the seeds of clusters of galaxies. The power spectrum estimates have a resolution Delta-l = 200 an...

  2. [Toothache with a neuropathic background].

    Science.gov (United States)

    Khatchaturian, V; de Wijer, A; Kalaykova, S I; Steenks, M H

    2015-03-01

    A 48-year old woman in good general health was referred to the orofacial pain clinic in a centre for special dentistry with a toothache in the premolar region of the left maxillary quadrant. The complaints had existed for 15 years and various dental treatments, including endodontic treatments, apical surgery, extraction and splint therapy, had not helped to alleviate the complaints. As a result of the fact that anti-epileptic drugs were able to reduce the pain it was concluded that this 'toothache' satisfied the criteria of an atypical odontalgia: 'toothache' with a neuropathic background. PMID:26181392

  3. Breast cancer - background and overview

    International Nuclear Information System (INIS)

    This summary is to provide the reader with a brief overview of the key concepts relating to epidemiology and etiology; clinical presentation and patterns of spread; Canadian guidelines for management; prognosis; and current Canadian screening recommendations in the diagnosis and treatment of breast cancer. This information will enable the reader to have the appropriate background knowledge before delving into the subsequent articles in this special CJMRT breast cancer edition. A variety of references have been provided for readers who are interested in more than a skeleton version of the current literature. (author)

  4. An introduction to radiation protection

    CERN Document Server

    Martin, Alan; Beach, Karen; Cole, Peter

    2012-01-01

    The sixth edition of this established text takes the reader through the general background to the subject, the technical principles underlying the control of radiation hazards, radiation detection and measurement and the biological effects of radiation. These are followed by a consideration of radiation protection issues in the nuclear industry, the non-nuclear sector and the medical field. Further specialised topics include risk assessment, waste management and decommissioning, radiological incidents and emergencies, relevant legislation and organizational issues.

  5. [Cosmic Microwave Background (CMB) Anisotropies

    Science.gov (United States)

    Silk, Joseph

    1998-01-01

    One of the main areas of research is the theory of cosmic microwave background (CMB) anisotropies and analysis of CMB data. Using the four year COBE data we were able to improve existing constraints on global shear and vorticity. We found that, in the flat case (which allows for greatest anisotropy), (omega/H)0 less than 10-7, where omega is the vorticity and H is the Hubble constant. This is two orders of magnitude lower than the tightest, previous constraint. We have defined a new set of statistics which quantify the amount of non-Gaussianity in small field cosmic microwave background maps. By looking at the distribution of power around rings in Fourier space, and at the correlations between adjacent rings, one can identify non-Gaussian features which are masked by large scale Gaussian fluctuations. This may be particularly useful for identifying unresolved localized sources and line-like discontinuities. Levin and collaborators devised a method to determine the global geometry of the universe through observations of patterns in the hot and cold spots of the CMB. We have derived properties of the peaks (maxima) of the CMB anisotropies expected in flat and open CDM models. We represent results for angular resolutions ranging from 5 arcmin to 20 arcmin (antenna FWHM), scales that are relevant for the MAP and COBRA/SAMBA space missions and the ground-based interferometer. Results related to galaxy formation and evolution are also discussed.

  6. [Cosmic Microwave Background (CMB) Anisotropies

    Science.gov (United States)

    Silk, Joseph

    1998-01-01

    One of the main areas of research is the theory of cosmic microwave background (CMB) anisotropies and analysis of CMB data. Using the four year COBE data we were able to improve existing constraints on global shear and vorticity. We found that, in the flat case (which allows for greatest anisotropy), (omega/H)0 less than 10(exp -7), where omega is the vorticity and H is the Hubble constant. This is two orders of magnitude lower than the tightest, previous constraint. We have defined a new set of statistics which quantify the amount of non-Gaussianity in small field cosmic microwave background maps. By looking at the distribution of power around rings in Fourier space, and at the correlations between adjacent rings, one can identify non-Gaussian features which are masked by large scale Gaussian fluctuations. This may be particularly useful for identifying unresolved localized sources and line-like discontinuities. Levin and collaborators devised a method to determine the global geometry of the universe through observations of patterns in the hot and cold spots of the CMB. We have derived properties of the peaks (maxima) of the CMB anisotropies expected in flat and open CDM models. We represent results for angular resolutions ranging from 5 arcmin to 20 arcmin (antenna FWHM), scales that are relevant for the MAP and COBRA/SAMBA space missions and the ground-based interferometer. Results related to galaxy formation and evolution are also discussed.

  7. Immunopathogenic Background of Pars Planitis.

    Science.gov (United States)

    Przeździecka-Dołyk, Joanna; Węgrzyn, Agnieszka; Turno-Kręcicka, Anna; Misiuk-Hojło, Marta

    2016-04-01

    Pars planitis is defined as an intermediate uveitis of unknown background of systemic disease with characteristic formations such as vitreous snowballs, snowbanks and changes in peripheral retina. The incidence of pars planitis varies 2.4-15.4 % of the uveitis patients. The pathogenesis of the disease is to be determined in future. Clinical and histopathological findings suggest an autoimmune etiology, most likely as a reaction to endogenous antigen of unknown source, with T cells predominant in both vitreous and pars plana infiltrations. T cells subsets play an important role as a memory-effector peripheral cell. Snowbanks are formed as an effect of post inflammatory glial proliferation of fibrous astrocytes. There is also a genetic predisposition for pars planitis by human leukocyte antigen and several other genes. A coexistence of multiple sclerosis and optic neuritis has been described in numerous studies. Epiretinal membrane, cataract, cystoid macular edema, retinal detachment, retinal vasculitis, neovascularization, vitreous peripheral traction, peripheral hole formation, vitreous hemorrhage, disc edema are common complications observed in pars planitis. There is a need to expand the knowledge of the pathogenic and immunologic background of the pars planitis to create an accurate pharmacological treatment. PMID:26438050

  8. Atmospheric physics. Background - methods - trends

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, Ulrich (ed.) [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    2012-11-01

    Presents more than 51 outstanding contributions of DLR-IPA to Atmospheric science. Gives a specific reference to Aerospace aspects. Prepared for educated laymen readers. Self-explaining. Understandable without the need to read references. On the occasion of the 50th anniversary of the Institute of Atmospheric Physics of the German Aerospace Center (DLR), this book presents more than 50 chapters highlighting results of the institute's research. The book provides an up-to-date, in-depth survey across the entire field of atmospheric science, including atmospheric dynamics, radiation, cloud physics, chemistry, climate, numerical simulation, remote sensing, instruments and measurements, as well as atmospheric acoustics. The authors have provided a readily comprehensible and self-contained presentation of the complex field of atmospheric science. The topics are of direct relevance for aerospace science and technology. Future research challenges are identified.

  9. The Flatness and Sudden Evolution of the Intergalactic Ionizing Background

    CERN Document Server

    Muñoz, Joseph A; Davies, Frederick B; Furlanetto, Steven R

    2014-01-01

    The ionizing background of cosmic hydrogen is an important probe of the sources and absorbers of ionizing radiation, their evolution and relationship, in the post-reionization universe. Previous studies show that the ionization rate should be very sensitive to changes in the source population: as the emissivity rises, absorbers shrink in size, increasing the ionizing mean free path and, hence, the ionizing background. By contrast, observations of the ionizing background find a very flat evolution from z~2-5, before falling precipitously at z~6. We resolve this discrepancy by pointing out that, at z~2-5, neutral absorbers are associated with the same collapsed halos that additionally host ionizing galactic sources. Thus, an increasing abundance of galaxies is compensated for by a corresponding increase in the absorber population, which moderates the instability in the ionizing background. However, by z~5-6, gas outside of halos dominates the absorption, the coupling between sources and absorbers is lost, and t...

  10. Progress in understanding the diffuse UV cosmic background

    Science.gov (United States)

    Henry, Richard Conn

    I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet spectrometer observations of the diffuse background shortward of Lalpha , including for the first time measurements made from the outermost regions of the solar system, where noise from solar-system scattered (and then grating-scattered) solar Lalpha is lowest. Also, we have obtained and are investigating the complete set of GALEX observations of the diffuse ultraviolet background longward of Lalpha . Preliminary investigation appears to confirm that longward of Lalpha there exists a component of the diffuse ultraviolet background that is not dust-scattered starlight.

  11. Progress in Understanding the Diffuse UV Cosmic Background

    CERN Document Server

    Henry, Richard Conn

    2012-01-01

    I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet spectrometer observations of the diffuse background shortward of Lyman alpha, including for the first time measurements made from the outermost regions of the solar system, where noise from solar-system scattered (and then grating-scattered) solar Lyman alpha is lowest. Also, we have obtained and are investigating the complete set of GALEX observations of the diffuse ultraviolet background longward of Lyman alpha. Preliminary investigation appears to confirm that longward of Lyman alpha there exists a component of the diffuse ultraviolet background that is not dust-scattered starlight.

  12. Spectral measurements of the cosmic microwave background

    International Nuclear Information System (INIS)

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs

  13. Spectral measurements of the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Kogut, A.J.

    1989-04-01

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs.

  14. Low background aspects of GERDA

    International Nuclear Information System (INIS)

    The GERDA experiment operates bare Germanium diodes enriched in 76Ge in an environment of pure liquid argon to search for neutrinoless double beta decay. A very low radioactive background is essential for the success of the experiment. We present here the research done in order to remove radio-impurities coming from the liquid argon, the stainless steel cryostat and the front-end electronics. We found that liquid argon can be purified efficiently from 222Rn. The main source of 222Rn in GERDA is the cryostat which emanates about 55 mBq. A thin copper shroud in the center of the cryostat was implemented to prevent radon from approaching the diodes. Gamma ray screening of radio-pure components for front-end electronics resulted in the development of a pre-amplifier with a total activity of less than 1 mBq 228Th.

  15. Polarization of Cosmic Microwave Background

    CERN Document Server

    Buzzelli, Alessandro; de Gasperis, Giancarlo; Vittorio, Nicola

    2016-01-01

    In this work we present an extension of the ROMA map-making code for data analysis of Cosmic Microwave Background polarization, with particular attention given to the inflationary polarization B-modes. The new algorithm takes into account a possible cross-correlated noise component among the different detectors of a CMB experiment. We tested the code on the observational data of the BOOMERanG (2003) experiment and we show that we are provided with a better estimate of the power spectra, in particular the error bars of the BB spectrum are smaller up to 20% for low multipoles. We point out the general validity of the new method. A possible future application is the LSPE balloon experiment, devoted to the observation of polarization at large angular scales.

  16. The Cosmic Background Imager 2

    CERN Document Server

    Taylor, Angela C; Allison, James R; Angelakis, Emmanouil; Bond, J Richard; Bronfman, Leonardo; Bustos, Ricardo; Davis, Richard J; Dickinson, Clive; Leech, Jamie; Mason, Brian S; Myers, Steven T; Pearson, Timothy J; Readhead, Anthony C S; Reeves, Rodrigo; Shepherd, Martin C; Sievers, Jonathan L

    2011-01-01

    We describe an upgrade to the Cosmic Background Imager instrument to increase its surface brightness sensitivity at small angular scales. The upgrade consisted of replacing the thirteen 0.9-m antennas with 1.4-m antennas incorporating a novel combination of design features, which provided excellent sidelobe and spillover performance for low manufacturing cost. Off-the-shelf spun primaries were used, and the secondary mirrors were oversized and shaped relative to a standard Cassegrain in order to provide an optimum compromise between aperture efficiency and low spillover lobes. Low-order distortions in the primary mirrors were compensated for by custom machining of the secondary mirrors. The secondaries were supported on a transparent dielectric foam cone to minimize scattering. The antennas were tested in the complete instrument, and the beam shape and spillover noise contributions were as expected. We demonstrate the performance of the telescope and the inter-calibration with the previous system using observ...

  17. Gauging the cosmic microwave background

    International Nuclear Information System (INIS)

    We provide a new derivation of the anisotropies of the cosmic microwave background (CMB), and find an exact expression that can be readily expanded perturbatively. Close attention is paid to gauge issues, with the motivation to examine the effect of super-Hubble modes on the CMB. We calculate a transfer function that encodes the behavior of the dipole, and examine its long-wavelength behavior. We show that contributions to the dipole from adiabatic super-Hubble modes are strongly suppressed, even in the presence of a cosmological constant, contrary to claims in the literature. We also introduce a naturally defined CMB monopole, which exhibits closely analogous long-wavelength behavior. We discuss the geometrical origin of this super-Hubble suppression, pointing out that it is a simple reflection of adiabaticity, and hence argue that it will occur regardless of the matter content.

  18. Background paper on aquaculture research

    DEFF Research Database (Denmark)

    Wenblad, Axel; Jokumsen, Alfred; Eskelinen, Unto;

    Torrissen, Norway, Senior Advisory Scientist Unto Eskelinen, Finland and Senior Advisory Scientist Alfred Jokumsen, Denmark. The WG performed an investigation of the Swedish aquaculture sector including interviews with a range of stakeholders within aquaculture research, farming organisations, authorities......The Board of MISTRA established in 2012 a Working Group (WG) on Aquaculture to provide the Board with background information for its upcoming decision on whether the foundation should invest in aquaculture research. The WG included Senior Advisor Axel Wenblad, Sweden (Chairman), Professor Ole...... tonnes of crayfish altogether corresponding to a total value of SEK 328 million in 2011. Further about 1,000 tonnes of fish and crustaceans were produced for restocking as well as about 3 million fry of salmon and trout were released into rivers. Swedish aquaculture research was overall assessed...

  19. The scientific background to decorporation

    International Nuclear Information System (INIS)

    The scientific background to chelation therapy is reviewed. A review of the animal studies which have demonstrated that in animals treated with DTPA either a reduction in bone tumour incidence from internally deposited 239Pu and 241Am, or a significant increase in survival time may occur, suggests that it is reasonable to assume that could also occur in humans. The biokinetics and bioinorganic chemistry of cobalt, caesium, thorium, uranium, neptunium, plutonium and americium after their entry into the systemic circulation are reviewed briefly. These reviews discuss the general biokinetic behaviour of each element in adult humans with special reference to those aspects of their bioinorganic chemistry that either underlie existing approaches to decorporation therapy, or which might be exploitable for new types of treatment. (author)

  20. Recognizing foreground-background interaction

    Science.gov (United States)

    Jenkins, Jeffrey; Szu, Harold

    2010-04-01

    Can the background affect a foreground target in distant, low-quality imagery? If it does, it might occur in our mind, or perhaps it may represent a snapshot of our early vision. An affirmative answer, one way or another, may affect our current understanding of this phenomena and potentially for related applications. How can we be sure about this in the psycho-physical sense? We begin with the physiology of our brain's homeostasis, of which an isothermal equilibrium is characterized by the minimum of Helmholtz isothermal Free Energy: A = U - T0S >= 0, where T0 = 37°C, the Boltzmann Entropy S = KB1n(W), and U is the unknown internal energy to be computed.