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Sample records for effect resonance radiation

  1. Giant resonance effects in radiative capture

    International Nuclear Information System (INIS)

    Snover, K.A.

    1979-01-01

    The technique of capture reaction studies of giant resonance properties is described, and a number of examples are given. Most of the recent work of interest has been in proton capture, in part because of the great utility (and availability) of polarized beams; most of the discussion concerns this reaction. Alpha capture, which has been a useful tool for exploring isoscalar E2 strength, and neutron capture are, however, also treated. 46 references, 14 figures

  2. Effect resonance radiation transfer of excitation porous silicon to I sub 2 molecules sorbed in pores

    CERN Document Server

    Zakharchenko, K V; Kuznetsov, M B; Chistyakov, A A; Karavanskij, V A

    2001-01-01

    One studies the effect of resonance radiation-free transfer of electronic excitation between silicon nanocrystals and iodine molecules sorbed in pores. The experiment procedure includes laser-induced luminescence and laser desorption mass spectrometry. One analyzes photoluminescence spectra prior to and upon iodine sorption. Excitation of iodine through the mechanism of resonance transfer is determined to result in desorption of the iodine sorbed molecules with relatively high kinetic energies (3-1 eV). One evaluated the peculiar distance of resonance transfer the approximate value of which was equal to 2 nm

  3. Radiation reaction effect on laser driven auto-resonant particle acceleration

    International Nuclear Information System (INIS)

    Sagar, Vikram; Sengupta, Sudip; Kaw, P. K.

    2015-01-01

    The effects of radiation reaction force on laser driven auto-resonant particle acceleration scheme are studied using Landau-Lifshitz equation of motion. These studies are carried out for both linear and circularly polarized laser fields in the presence of static axial magnetic field. From the parametric study, a radiation reaction dominated region has been identified in which the particle dynamics is greatly effected by this force. In the radiation reaction dominated region, the two significant effects on particle dynamics are seen, viz., (1) saturation in energy gain by the initially resonant particle and (2) net energy gain by an initially non-resonant particle which is caused due to resonance broadening. It has been further shown that with the relaxation of resonance condition and with optimum choice of parameters, this scheme may become competitive with the other present-day laser driven particle acceleration schemes. The quantum corrections to the Landau-Lifshitz equation of motion have also been taken into account. The difference in the energy gain estimates of the particle by the quantum corrected and classical Landau-Lifshitz equation is found to be insignificant for the present day as well as upcoming laser facilities

  4. Resonance effects of transition radiation emitted from thin foil stacks using electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Awata, Takaaki; Yajima, Kazuaki; Tanaka, Takashi [Kyoto Univ. (Japan). Faculty of Engineering; and others

    1997-03-01

    Transition Radiation(TR) X rays are expected to be a high brilliant X-ray source because the interference among TR X rays emitted from many thin foils placed periodically in vacuum can increase their intensity and make them quasi-monochromatic. In order to study the interference (resonance) effects of TR, we measured the energy spectra of TR for several sets of thin-foil stacks at various emission angles. It was found that the resonance effects of TR are classified into intrafoil and interfoil resonances and the intensity of TR X rays increases nonlinearly with increasing foil number, attributing to the interfoil resonance. It became evident that the brilliance of TR is as high as that of SR. (author)

  5. Resonance detection of Moessbauer radiation

    International Nuclear Information System (INIS)

    Morozov, V.V.

    1985-01-01

    The resonance detection method as compared with the usual method of registering Moessbauer spectra has a number of advantages, one of which is the increase of resolution of the Moessbauer spectrum. The method is based on the modulation of a secondary radiation of a converter tuned in the resonance with the Moessbauer gamma-quantum source. The resonance detection method with account of supression, secondary radiation outgoing from the converter is investigated. The converter represents a substrate enriched by the Moessbauer isotope placed either inside the gas counter, or coupled with any other detecting device. Analytical expressions for Moessbauer spectrum parameters: effect, area and width of the spectral line are derived. It is shown that the joint application of usual and resonance detection methods for registering the Moessbauer spectrum allows one to determine parameters of the source, converter and the investigated absorber

  6. Magnetic resonance imaging of radiation optic neuropathy

    International Nuclear Information System (INIS)

    Zimmerman, C.F.; Schatz, N.J.; Glaser, J.S.

    1990-01-01

    Three patients with delayed radiation optic neuropathy after radiation therapy for parasellar neoplasms underwent magnetic resonance imaging. The affected optic nerves and chiasms showed enlargement and focal gadopentetate dimeglumine enhancement. The magnetic resonance imaging technique effectively detected and defined anterior visual pathway changes of radionecrosis and excluded the clinical possibility of visual loss because of tumor recurrence

  7. Review of meson resonance radiative decays

    International Nuclear Information System (INIS)

    Thorndike, E.H.

    1977-01-01

    The radiative decays of meson resonances can be studied by three different approaches, it is noted. These are the meson-exchange, Primakoff effect, and the production of the desired resonance and subsequent observation of its decay. These approaches are criticized and examples of them are reviewed. Mass distributions are shown and branching ratios discussed. 21 references

  8. Early radiation effects in highly apoptotic murine lymphoma xenografts monitored by 31P magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Sakurai, Hideyuki; Mitsuhashi, Norio; Murata, Osamu; Kitamoto, Yoshizumi; Saito, Yoshihiro; Hasegawa, Masatoshi; Akimoto, Tetsuo; Takahashi, Takeo; Nasu, Sachiko; Niibe, Hideo

    1998-01-01

    Purpose: Phosphorus-31 magnetic resonance spectra ( 31 P-MRS) were obtained from highly apoptotic murine lymphoma xenografts before and up to 24 hr following graded doses of radiation ranging from 2 to 30 Gy. Radiation-induced apoptosis was also estimated up to 24 hr by scoring apoptotic cells in tumor tissue. Methods and Materials: Highly apoptotic murine lymphoma cells, EL4, were subcutaneously transplanted into C57/BL mice. At 7 days after transplantation, radiation was given to the tumor with a single dose at 3, 10, and 30 Gy. The β-ATP/Pi, PME/Pi, and β-ATP/PME values were calculated from the peak area of each spectrum. Radiation-induced apoptosis was scored with counting apoptotic cells on hematoxylin and eosin stained specimens (%apoptosis). Results: The values of % apoptosis 4, 8, and 24 hr after radiation were 21.8, 19.6, and 4.6% at 3 Gy, 35.1, 25.6, and 14.8% at 10 Gy, 38.4, 38.0, and 30.6% at 30 Gy, respectively (cf. 4.4% in control). There was no correlation between early change in β-ATP/Pi and % apoptosis at 4 hr after radiation when most of the apoptosis occurred. An early decrease in PME/Pi was observed at 4 hr after radiation dose at 30 Gy. For each dose, the values of β-ATP/Pi 24 hr after radiation were inversely related to radiation dose. Conclusion: The increase in β-ATP/Pi observed by 31 P-MRS was linked to the degree of histological recovery from radiation-induced apoptosis

  9. Partial radiative capture of resonance neutrons

    International Nuclear Information System (INIS)

    Samour, C.

    1969-01-01

    The radiative capture of resonance neutrons has been studied near the Saclay linac between 0.5 and 700 eV with time-of-flight method and a Ge(Li) detector. 195 Pt + n and 183 W + n allow the study of the distribution of partial radiative widths and their eventual correlation and also the variation of γ i > with E γ . The mean values of Ml and El transition intensities are compared in several tin isotopes. Interference effects, either between resonances or between direct capture and resonant capture are found in 195 Pt + n, 197 Au + n and 59 Co + n. The excited level schemes of a great deal of nuclei are obtained and compared with theoretical predictions. This study has been completed by an analysis of thermal spectrum. (author) [fr

  10. Effect of Prostate Magnetic Resonance Imaging/Ultrasound Fusion-guided Biopsy on Radiation Treatment Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Aaron; Valle, Luca F.; Shankavaram, Uma; Krauze, Andra; Kaushal, Aradhana; Schott, Erica; Cooley-Zgela, Theresa [Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Wood, Bradford [Center for Interventional Oncology, National Institutes of Health, Bethesda, Maryland (United States); Pinto, Peter [Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Choyke, Peter; Turkbey, Baris [Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Citrin, Deborah E., E-mail: citrind@mail.nih.gov [Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)

    2017-04-01

    Purpose: Targeted magnetic resonance imaging (MRI)/ultrasound fusion prostate biopsy (MRI-Bx) has recently been compared with the standard of care extended sextant ultrasound-guided prostate biopsy (SOC-Bx), with the former associated with an increased rate of detection of clinically significant prostate cancer. The present study sought to determine the influence of MRI-Bx on radiation therapy and androgen deprivation therapy (ADT) recommendations. Methods and Materials: All patients who had received radiation treatment and had undergone SOC-Bx and MRI-Bx at our institution were included. Using the clinical T stage, pretreatment prostate-specific antigen, and Gleason score, patients were categorized into National Comprehensive Cancer Network risk groups and radiation treatment or ADT recommendations assigned. Intensification of the recommended treatment after multiparametric MRI, SOC-Bx, and MRI-Bx was evaluated. Results: From January 2008 to January 2016, 73 patients received radiation therapy at our institution after undergoing a simultaneous SOC-Bx and MRI-Bx (n=47 with previous SOC-Bx). Repeat SOC-Bx and MRI-Bx resulted in frequent upgrading compared with previous SOC-Bx (Gleason score 7, 6.7% vs 44.6%; P<.001; Gleason score 8-10, 2.1% vs 38%; P<.001). MRI-Bx increased the proportion of patients classified as very high risk from 24.7% to 41.1% (P=.027). Compared with SOC-Bx alone, including the MRI-Bx findings resulted in a greater percentage of pathologically positive cores (mean 37% vs 44%). Incorporation of multiparametric MRI and MRI-Bx results increased the recommended use and duration of ADT (duration increased in 28 of 73 patients and ADT was added for 8 of 73 patients). Conclusions: In patients referred for radiation treatment, MRI-Bx resulted in an increase in the percentage of positive cores, Gleason score, and risk grouping. The benefit of treatment intensification in accordance with the MRI-Bx findings is unknown.

  11. Resonant-bar gravitational radiation antennas

    International Nuclear Information System (INIS)

    Blair, D.G.

    1987-01-01

    This paper reviews the concept of gravitational radiation, and describes the worldwide research programme for the development of high-sensitivity resonant-bar antennas which are aimed at detecting gravitational radiation from astrophysical sources. (author)

  12. Resonant acoustic radiation force optical coherence elastography

    OpenAIRE

    Qi, Wenjuan; Li, Rui; Ma, Teng; Li, Jiawen; Kirk Shung, K.; Zhou, Qifa; Chen, Zhongping

    2013-01-01

    We report on a resonant acoustic radiation force optical coherence elastography (ARF-OCE) technique that uses mechanical resonant frequency to characterize and identify tissues of different types. The linear dependency of the resonant frequency on the square root of Young's modulus was validated on silicone phantoms. Both the frequency response spectrum and the 3D imaging results from the agar phantoms with hard inclusions confirmed the feasibility of deploying the resonant frequency as a mec...

  13. Using nitrogen-14 nuclear quadrupole resonance and electric field gradient information for the study of radiation effects

    International Nuclear Information System (INIS)

    Iselin, L.H.

    1995-12-01

    Nitrogen-14 nuclear quadrupole resonance (NQR) was used in an attempt to detect the effects of ionizing radiation on organic material. Previously reported resonances for urea were detected at 2,913.32 ± 0.01 kHz and 2,347.88 ± 0.08 kHz with associated T 2 * values 780 ± 20 micros and 523 ± 24 micros, respectively. The previously unreported ν - line for urea-d 4 was detected at 2,381 ± 0.04 Khz and used to determine accurately for the first time the values for the nuclear quadrupole coupling constant χ (3,548.74 ± 0.03 kHz) and the asymmetry parameter η (0.31571 ± 0.00007) for urea-d 4 . The inverse linewidth parameter T 2 * for ν + was measured at 928 ± 23 micros and for ν - at 721 ± 12 micros. Townes and Dailey analysis was performed and urea-d 4 exhibits a 0.004 increase in lone pair electronic density and a slight decrease in N-H bond electronic density, as compared to urea, probably due to the mass difference. A relationship is proposed, referred to as NQR linewidth analysis, between the dynamic spin relaxation times T 2 and T 2 * and the widths of the distributions of the NQR parameters. Linewidth analysis is presented as a tool for possible use in future NQR work in all area, not just radiation effects. This relationship is tested using sodium nitrite T 2 and T 2 * values for ν - and ν - as a function of temperature

  14. Investigations of radiation pressure : optical side-band cooling of a trampoline resonator and the effect of superconductivity on the Casimir force

    NARCIS (Netherlands)

    Eerkens, H.J.

    2017-01-01

    This thesis consists of two subjects, that are both a consequence of radiation pressure. In optomechanics, light is used to influence the motion of a trampoline resonator. It is possible to slow down this motion, cooling it from room temperature to an effective temperature of several milllikelvins,

  15. Micromechanical Resonator Driven by Radiation Pressure Force.

    Science.gov (United States)

    Boales, Joseph A; Mateen, Farrukh; Mohanty, Pritiraj

    2017-11-22

    Radiation pressure exerted by light on any surface is the pressure generated by the momentum of impinging photons. The associated force - fundamentally, a quantum mechanical aspect of light - is usually too small to be useful, except in large-scale problems in astronomy and astrodynamics. In atomic and molecular optics, radiation pressure can be used to trap or cool atoms and ions. Use of radiation pressure on larger objects such as micromechanical resonators has been so far limited to its coupling to an acoustic mode, sideband cooling, or levitation of microscopic objects. In this Letter, we demonstrate direct actuation of a radio-frequency micromechanical plate-type resonator by the radiation pressure force generated by a standard laser diode at room temperature. Using two independent methods, the magnitude of the resonator's response to forcing by radiation pressure is found to be proportional to the intensity of the incident light.

  16. Evaluation of hyperpolarized [1-¹³C]-pyruvate by magnetic resonance to detect ionizing radiation effects in real time.

    Science.gov (United States)

    Sandulache, Vlad C; Chen, Yunyun; Lee, Jaehyuk; Rubinstein, Ashley; Ramirez, Marc S; Skinner, Heath D; Walker, Christopher M; Williams, Michelle D; Tailor, Ramesh; Court, Laurence E; Bankson, James A; Lai, Stephen Y

    2014-01-01

    Ionizing radiation (IR) cytotoxicity is primarily mediated through reactive oxygen species (ROS). Since tumor cells neutralize ROS by utilizing reducing equivalents, we hypothesized that measurements of reducing potential using real-time hyperpolarized (HP) magnetic resonance spectroscopy (MRS) and spectroscopic imaging (MRSI) can serve as a surrogate marker of IR induced ROS. This hypothesis was tested in a pre-clinical model of anaplastic thyroid carcinoma (ATC), an aggressive head and neck malignancy. Human ATC cell lines were utilized to test IR effects on ROS and reducing potential in vitro and [1-¹³C] pyruvate HP-MRS/MRSI imaging of ATC orthotopic xenografts was used to study in vivo effects of IR. IR increased ATC intra-cellular ROS levels resulting in a corresponding decrease in reducing equivalent levels. Exogenous manipulation of cellular ROS and reducing equivalent levels altered ATC radiosensitivity in a predictable manner. Irradiation of ATC xenografts resulted in an acute drop in reducing potential measured using HP-MRS, reflecting the shunting of reducing equivalents towards ROS neutralization. Residual tumor tissue post irradiation demonstrated heterogeneous viability. We have adapted HP-MRS/MRSI to non-invasively measure IR mediated changes in tumor reducing potential in real time. Continued development of this technology could facilitate the development of an adaptive clinical algorithm based on real-time adjustments in IR dose and dose mapping.

  17. Evaluation of hyperpolarized [1-¹³C]-pyruvate by magnetic resonance to detect ionizing radiation effects in real time.

    Directory of Open Access Journals (Sweden)

    Vlad C Sandulache

    Full Text Available Ionizing radiation (IR cytotoxicity is primarily mediated through reactive oxygen species (ROS. Since tumor cells neutralize ROS by utilizing reducing equivalents, we hypothesized that measurements of reducing potential using real-time hyperpolarized (HP magnetic resonance spectroscopy (MRS and spectroscopic imaging (MRSI can serve as a surrogate marker of IR induced ROS. This hypothesis was tested in a pre-clinical model of anaplastic thyroid carcinoma (ATC, an aggressive head and neck malignancy. Human ATC cell lines were utilized to test IR effects on ROS and reducing potential in vitro and [1-¹³C] pyruvate HP-MRS/MRSI imaging of ATC orthotopic xenografts was used to study in vivo effects of IR. IR increased ATC intra-cellular ROS levels resulting in a corresponding decrease in reducing equivalent levels. Exogenous manipulation of cellular ROS and reducing equivalent levels altered ATC radiosensitivity in a predictable manner. Irradiation of ATC xenografts resulted in an acute drop in reducing potential measured using HP-MRS, reflecting the shunting of reducing equivalents towards ROS neutralization. Residual tumor tissue post irradiation demonstrated heterogeneous viability. We have adapted HP-MRS/MRSI to non-invasively measure IR mediated changes in tumor reducing potential in real time. Continued development of this technology could facilitate the development of an adaptive clinical algorithm based on real-time adjustments in IR dose and dose mapping.

  18. Effects of electromagnetic radiation produced by 3G mobile phones on rat brains: magnetic resonance spectroscopy, biochemical, and histopathological evaluation.

    Science.gov (United States)

    Dogan, M; Turtay, M G; Oguzturk, H; Samdanci, E; Turkoz, Y; Tasdemir, S; Alkan, A; Bakir, S

    2012-06-01

    The effects of electromagnetic radiation (EMR) produced by a third-generation (3G) mobile phone (MP) on rat brain tissues were investigated in terms of magnetic resonance spectroscopy (MRS), biochemistry, and histopathological evaluations. The rats were randomly assigned to two groups: Group 1 is composed of 3G-EMR-exposed rats (n = 9) and Group 2 is the control group (n = 9). The first group was subjected to EMR for 20 days. The control group was not exposed to EMR. Choline (Cho), creatinin (Cr), and N-acetylaspartate (NAA) levels were evaluated by MRS. Catalase (CAT) and glutathione peroxidase (GSH-Px) enzyme activities were measured by spectrophotometric method. Histopathological analyses were carried out to evaluate apoptosis in the brain tissues of both groups. In MRS, NAA/Cr, Cho/Cr, and NAA/Cho ratios were not significantly different between Groups 1 and 2. Neither the oxidative stress parameters, CAT and GSH-Px, nor the number of apoptotic cells were significantly different between Groups 1 and 2. Usage of short-term 3G MP does not seem to have a harmful effect on rat brain tissue.

  19. Partial radiative capture of resonance neutrons; Capture radiative partielle des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Samour, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    The radiative capture of resonance neutrons has been studied near the Saclay linac between 0.5 and 700 eV with time-of-flight method and a Ge(Li) detector. {sup 195}Pt + n and {sup 183}W + n allow the study of the distribution of partial radiative widths and their eventual correlation and also the variation of < {gamma}{sub {gamma}{sub i}} > with E{sub {gamma}}. The mean values of Ml and El transition intensities are compared in several tin isotopes. Interference effects, either between resonances or between direct capture and resonant capture are found in {sup 195}Pt + n, {sup 197}Au + n and {sup 59}Co + n. The excited level schemes of a great deal of nuclei are obtained and compared with theoretical predictions. This study has been completed by an analysis of thermal spectrum. (author) [French] La capture radiative des neutrons de resonance a ete etudiee pres de l'accelerateur lineaire de Saclay entre 0,5 et 700 eV a l'aide de la methode du temps-de-vol et d'un detecteur Ge(Li). Les noyaux {sup 195}Pt + n et {sup 183}W + n permettent l'analyse de la distribution de resonance en resonance des largeurs radiatives partielles {gamma}{sub {gamma}{sub i}} et de leur eventuelle correlation, ainsi que l'etude de la variation de < {gamma}{sub {gamma}{sub i}} > en fonction de E{sub {gamma}}. Les intensites moyennes des transitions Ml et El sont comparees pour quelques isotopes de l'etain. Des effets d'interference, soit entre resonances, soit entre capture directe et capture resonnante sont mis en evidence dans {sup 195}Pt + n, {sup 197}Au + n et {sup 59}Co + n. Enfin les schemas des etats excites d'un grand nombre de noyaux sont obtenus et compares avec les predictions theoriques. Cette etude a ete completee par une analyse des spectres thermiques. (auteur)

  20. Partial radiative capture of resonance neutrons; Capture radiative partielle des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Samour, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    The radiative capture of resonance neutrons has been studied near the Saclay linac between 0.5 and 700 eV with time-of-flight method and a Ge(Li) detector. {sup 195}Pt + n and {sup 183}W + n allow the study of the distribution of partial radiative widths and their eventual correlation and also the variation of < {gamma}{sub {gamma}{sub i}} > with E{sub {gamma}}. The mean values of Ml and El transition intensities are compared in several tin isotopes. Interference effects, either between resonances or between direct capture and resonant capture are found in {sup 195}Pt + n, {sup 197}Au + n and {sup 59}Co + n. The excited level schemes of a great deal of nuclei are obtained and compared with theoretical predictions. This study has been completed by an analysis of thermal spectrum. (author) [French] La capture radiative des neutrons de resonance a ete etudiee pres de l'accelerateur lineaire de Saclay entre 0,5 et 700 eV a l'aide de la methode du temps-de-vol et d'un detecteur Ge(Li). Les noyaux {sup 195}Pt + n et {sup 183}W + n permettent l'analyse de la distribution de resonance en resonance des largeurs radiatives partielles {gamma}{sub {gamma}{sub i}} et de leur eventuelle correlation, ainsi que l'etude de la variation de < {gamma}{sub {gamma}{sub i}} > en fonction de E{sub {gamma}}. Les intensites moyennes des transitions Ml et El sont comparees pour quelques isotopes de l'etain. Des effets d'interference, soit entre resonances, soit entre capture directe et capture resonnante sont mis en evidence dans {sup 195}Pt + n, {sup 197}Au + n et {sup 59}Co + n. Enfin les schemas des etats excites d'un grand nombre de noyaux sont obtenus et compares avec les predictions theoriques. Cette etude a ete completee par une analyse des spectres thermiques. (auteur)

  1. Inactivation of bacteriophage T1 by the Auger effect following phosphorus resonance absorption of monoenergetic synchrotron radiation

    International Nuclear Information System (INIS)

    Furusawa, Yoshiya; Maezawa, Hiroshi; Suzuki, Kenshi; Kobayashi, Katsumi; Suzuki, Masao; Hieda, Kotaro

    1992-01-01

    Killing effect on bacteriophage T1 by the Auger cascade of phosphorus in DNA following K shell photoabsorption was studied with monoenergetic X rays obtained from synchrotron radiations. Phages embedded in nutrient broth were irradiated under vacuum with X rays at the resonance peak (2,153 eV), and below (2,147 eV) and above (2,159 eV) the peak. The corresponding mean lethal exposures (D 0 ) were 554, 332 and 434 kR, respectively. The Auger enhancements, as an energy dependent fractional increment of phase sensitivity, were 0.67 at 2,153 eV and 0.28 at 2,159 eV. Using the DNA absorption spectrum measured in this experiment, photoionization cross sections of Scofield (17), and the Auger yield after creation of a K shell vacancy, the number of phosphorus Auger cascades in one phage DNA at D 0 were calculated to be 0.00, 0.98 and 0.25 at 2,147, 2,153 and 2,159 eV, respectively. Comparison between the Auger enhancement of phage killing and the number of Auger cascades indicated that one phosphorus Auger cascade in phage DNA caused about 0.41 (at 2,153 eV) or 0.84 (at 2,159 eV) lethal events

  2. Radiative widths of resonances (experiments)

    International Nuclear Information System (INIS)

    Gidal, G.

    1988-07-01

    After a hiatus of several years, this conference brings us considerable new data on resonance production in photon photon interactions. I will first discuss the contributions concerning the tensor, pseudoscalar and scalar mesons, then review the current status of the (c/ovr string/c /eta//sub c/) and finally summarize the exciting new results concerning the spin 1 mesons. 40 refs., 21 figs., 7 tabs

  3. Dosimetry of ionizing radiations by Electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Azorin N, J.

    2005-01-01

    In this work, some historical and theoretical aspects about the Electron Paramagnetic Resonance (EPR), its characteristics, the resonance detection, the paramagnetic species, the radiation effects on inorganic and organic materials, the diagrams of the instrumentation for the EPR detection, the performance of an EPR spectrometer, the coherence among EPR and dosimetry and, practical applications as well as in the food science there are presented. (Author)

  4. Isotopic effect giant resonances

    International Nuclear Information System (INIS)

    Buenerd, M.; Lebrun, D.; Martin, P.; Perrin, G.; Saintignon, P. de; Chauvin, J.; Duhamel, G.

    1981-10-01

    The systematics of the excitation energy of the giant dipole, monopole, and quadrupole resonances are shown to exhibit an isotopic effect. For a given element, the excitation energy of the transition decreases faster with the increasing neutron number than the empirical laws fitting the overall data. This effect is discussed in terms of the available models

  5. An analytical method for estimating the 14N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

    International Nuclear Information System (INIS)

    Iselin, L.H.

    1992-01-01

    The use of 14 N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing 14 N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The 14 N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation

  6. An analytical method for estimating the 14N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

    Energy Technology Data Exchange (ETDEWEB)

    Iselin, Louis Henry [Univ. of Florida, Gainesville, FL (United States)

    1992-01-01

    The use of 14N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing 14N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The 14N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation.

  7. Radiation effects

    International Nuclear Information System (INIS)

    Collings, E.W.

    1986-01-01

    An important cause of deterioration in superconducting magnets intended for high-energy physics and fusion-reactor applications is radiation damage. The present chapter deals chiefly with the effects of electron, proton, gamma and neutron irradiation on the properties of stabilized Ti-Nb-base composite superconductors. The authors examine the particle-accelerator environment, electron irradiation of Ti-Nb superconductor, proton irradiation of Ti-Nb superconductor and its stabilizer, and deuteron irradiation of Ti-Nb superconductor. A section discussing the fusion reactor environment in general is presented, and the two principal classes of fusion reactor based on the magnetic-confinement concept, namely the tokamak and the mirrormachine are examined. Also discussed is neutron irradiation of Cu/TiNb composite superconductors and critical current density of neutronirradiated Ti-Nb. Finally, radiation damage to stabilizer and insulating materials is described

  8. Radiation effects in the polycarbonate of bisphenol-A. Thermoluminescence electron spin resonance and charged particle track studies

    International Nuclear Information System (INIS)

    Edmonds, E.A.

    1978-09-01

    A detailed investigation is presented of the thermoluminescence observable above room temperature from the polycarbonate of bisphenol-A after its exposure to different radiations. A correlation study is described by which features of the complex thermoluminescence glow curve from a commercial grade of the polycarbonate of bisphenol-A are related to the etchability of charged particle damage trails and the radiogenic ESR signal. A model is presented whereby the etchability of charged particle damage trails is associated with chain scission caused by the high local dose of radiation in the vicinity of the trajectories of charged particles. Methods by which activation constants controlling the thermoluminescence glow curve can be evaluated are discussed and results are presented. It is concluded that glow peaks associated with the ESR signal or enhanced etchability are related to small-scale motions in the molecular matrix of the polycarbonate of bisphenol-A. These motions are thermally activated in accord with the simple Boltzmann relation usually incorporated into theories of thermoluminescence. Another component glow peak of the thermoluminescence glow curve is shown to be associated with the glass-rubber transition in the polycarbonate of bisphenol-A. Different features of the thermoluminescence glow curve can be related to relaxations of the polymer matrix and decomposition of the matrix. It is confirmed that the dominant bulk effect of radiation in the polycarbonate of bisphenol-A exposed to large doses of radiation is chain scission. (author)

  9. The assessment of chemotherapy and radiation therapy effect in malignant lymphomas with computed tomography and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Dobrovolskiene, L.; Griniute, R.

    2003-01-01

    Aim of this study was to estimate the diagnostic possibilities of computed tomography (CT) and magnetic resonance imaging (MRI) in the assessment of treatment effect in malignant lymphomas. In the period of 1998 to 2002, 196 patients with histologically proven malignant lymphoma were examined in the Department of Tomography of Kaunas University of Medicine Hospital. The data were processed with SPSS 10.1, including application of standardized t-test and classification of Fisher's statistics. In this group the density of lymphomatous masses prior and post treatment has no difference on CT images, thus the differentiation of active tissue and relapse is not possible. On MR images the difference of signal intensity of the active component (not treated) and fibrous remnant is significant. MRI is a radiological method which provides information about activity of lymphomatous tissue and is able to delineate the active component (recidive or partial remission) and inactive remnant (total remission) of the tumor mass and thus facilitating the diagnosis of possible relapse of malignant lymphomas for hematology, chemotherapy and radiotherapy specialists. (author)

  10. Radiation dosimetry using magnetic resonance imaging

    International Nuclear Information System (INIS)

    Olsson, L.E.

    1991-01-01

    A new dosimetry system for 3D dose distribution measurements based on the Fricke dosimeter and magnetic resonance imaging (MRI) has been developed. The dosimeter consists of a ferrous sulphate solution incorporated in an agarose gel, which together constitute the dosimeter gel. The absorbed dose to the gel is measured by means of the proton spin-lattice relaxation rate, 1/T1 in an MR scanner. The dose distribution to an arbitrary slice within a dosimeter gel phantom can thus be determined. The chemical yield of the dosimeter gel is significantly higher than that of the for Fricke solution, and is strongly dependent of the initial ferrous sulphate concentration, assuming that the gel is bubbled with oxygen during preparation. A gel of 1.5 mM [Fe 2+ ] and 50 mM [H 2 SO 4 ] has a sensitivity of 0.108 s -1 Gy -1 and is linear up to 50 Gy. The dosimeter gel has uniform dose response over large volumes. Above 50 mM[H 2 SO 4 ] the yield increases only slightly, but the gel strength decreases and results in gel phantoms with non-uniform dose response. Below 50 mM[H 2 SO 4 ] the sensitivity of the dosimeter falls rapidly due to the decreased relaxivity of the ferric ions. The high chemical yield can be explained by a chain reaction and a reaction scheme is accordingly proposed. The dosimeter gel shows no dependence on dose rate or radiation quality and can be regarded as water-equivalent with respect to the interaction of the radiation. The diffusion coefficient of the ferric ions in the agarose gel is 1.19x10 -2 cm 2 /h. The diffusion blurs the dosimeteric image, but poses only a minor problem if the MR measurements are completed within the first two hours after irradiation. Dose distribution data from external radiation therapy units have been determined using the dosimeter gel and MRI with good accuracy, but the precision is poor, about 5-10%. (au) (84 refs.)

  11. Effect of the background radiation of a copper vapor laser with an unstable resonator on dye lasing

    Energy Technology Data Exchange (ETDEWEB)

    Elaev, V F; Mirza, S M; Sukhanov, V B; Troitskii, V O; Soldatov, A N

    1986-05-01

    Results of an experimental study of the emission divergence of a copper vapor laser with an unstable resonator are reported. It is shown that a copper vapor laser beam can be conveniently treated as a pair of components with a divergence higher or lower than a certain optimal value; the percent ratio of the components varies with the pulse repetition frequency. In the case where a copper vapor laser is used to pump a dye laser, the contribution of the component with the higher divergence to dye lasing does not exceed 1 percent. 7 references.

  12. Electron spin resonance studies of radiation effects. Final report, 1964-1979 (including annual progress reports for 1978 and 1979)

    International Nuclear Information System (INIS)

    Rogers, M.T.

    1979-07-01

    The discovery of new free radicals, largely in irradiated single crystals of nonmetallic solids, and the determination of the molecular and electronic structures of these paramagnetic species by electron spin resonance (ESR) spectroscopy, have been carried out using a wide variety of organic and inorganic materials. The mechanisms of production of radicals in solids, their motions, and their reactions have been investigated and some applicable general principles deduced. Emphasis has been on aliphatic free radicals from irradiated carboxylic acids and amides and their halogen-substituted derivatives, organometallic radicals and substituted cyclic hydrocarbon radicals; inorganic radicals studied include V centers, hypervalent radicals and electron adducts. Extensive investigations of paramagnetic transition metal complexes, particularly cyanides and fluorides, have been made. In all cases quantum mechanical calculations have been employed as far as possible in interpreting the data. An improved method for analyzing experimental ESR spectra of single crystals has been developed and a number of crystal structures have been determined to supplement the ESR studies. Applications of nuclear quadrupole resonance spectroscopy to the study of structure and bonding in inorganic solids have been made and a method for using nuclear magnetic relaxation data for estimating quadrupole coupling constants in liquids has been developed

  13. Absorption of resonant electromagnetic radiation in electron-atom collisions

    International Nuclear Information System (INIS)

    Arslanbekov, T.U.; Pazdzerskii, V.A.; Usachenko, V.I.

    1986-01-01

    Nonrelativistic quantum theory is used to study the possibility of amplification of electromagnetic radiation in forced braking scattering of an electron beam on atoms. The interaction of the atom with the electromagnetic field is considered in the resonant approximation. Cases of large and small detuning from resonance are considered. It is shown that for any orientation of the electron beam relative to the field polarization vector, absorption of radiation occurs, with the major contribution being produced by atomic electrons

  14. Non-resonant diagrams in radiative four-fermion processes

    International Nuclear Information System (INIS)

    Fujimoto, J.; Ishikawa, T.; Kawabata, S.; Kurihara, Y.; Perret-Gallix, D.

    1994-06-01

    The complete tree level cross section for e + e - → e - ν-bar e ud-barγ is computed and discussed in comparison with the cross sections for e + e - → e - V-bar e u d-bar and e + e - → u-bar d u d-bar. Event generators based on the GRACE package for the non-radiative and radiative case are presented. Special interest is brought to the effect of the non-resonant diagrams overlooked so far in other studies. Their contribution to the total cross section is presented for the LEP II energy range for future linear colliders (√s = 500 GeV). (author)

  15. Radiation effects at ISABELLE

    International Nuclear Information System (INIS)

    Sanger, P.A.; Danby, G.T.

    1975-01-01

    Shielding, radiation damage, and radiation heating at the planned ISABELLE storage rings were considered. Radiation shielding studies were reviewed and were found to be adequate for present day dosage limits. Radiation damage could be encountered in some extreme cases, but is not expected to limit the performance of the superconducting magnets. Experiments to study the effect of radiation heating on actual magnets are recommended

  16. Effects of thermal annealing on the radiation produced electron paramagnetic resonance spectra of bovine and equine tooth enamel: Fossil and modern

    International Nuclear Information System (INIS)

    Weeks, Robert A.; Bogard, James S.; Elam, J. Michael; Weinand, Daniel C.; Kramer, Andrew

    2003-01-01

    The concentration of stable radiation-induced paramagnetic states in fossil teeth can be used as a measure of sample age. Temperature excursions >100 deg. C, however, can cause the paramagnetic state clock to differ from the actual postmortem time. We have heated irradiated enamel from both fossilized bovid and modern equine (MEQ) teeth for 30 min in 50 deg. C increments from 100 to 300 deg. C, measuring the electron paramagnetic resonance (EPR) spectrum after each anneal, to investigate such effects. Samples were irradiated again after the last anneal, with doses of 300-1200 Gy from 60 Co photons, and measured. Two unirradiated MEQ samples were also annealed for 30 min at 300 deg. C, one in an evacuated EPR tube and the other in a tube open to the atmosphere, and subsequently irradiated. The data showed that hyperfine components attributed to the alanine radical were not detected in the irradiated MEQ sample until after the anneals. The spectrum of the MEQ sample heated in air and then irradiated was similar to that of the heat treated fossil sample. We conclude that the hyperfine components are due to sample heating to temperatures/times >100 deg. C/30 min and that similarities between fossil and MEQ spectra after the 300 deg. C/30 min MEQ anneal are also due to sample heating. We conclude that the presence of the hyperfine components in spectra of fossil tooth enamel indicate that such thermal events occurred either at the time of death, or during the postmortem history

  17. Absorption of continuum radiation in a resonant expanding gaseous sphere

    International Nuclear Information System (INIS)

    Shaparev, N Y

    2014-01-01

    The paper deals with absorption of external continuum radiation in a self-similarly expanding gaseous sphere. Frequency probability and integral probability of radiation absorption in the resonance frequency range are determined depending on the expansion velocity gradient and thickness of the optical medium. It is shown that expansion results in a reduced optical thickness of the medium and enhanced integral absorption. (paper)

  18. Resonance in the restricted problem caused by solar radiation pressure

    International Nuclear Information System (INIS)

    Bhatnagar, K.B.; Gupta, B.

    1977-01-01

    Resonance is discussed in the motion of an artificial Earth satellite caused by solar radiation pressure. The Hamiltonian and the generating functions occurring in the problem are expanded in the power series of small parameter β, which depends on solar radiation pressure. Also the perturbations in the osculating elements are obtained up to O(βsup(1/2)). (author)

  19. Tuner and radiation shield for planar electron paramagnetic resonance microresonators

    International Nuclear Information System (INIS)

    Narkowicz, Ryszard; Suter, Dieter

    2015-01-01

    Planar microresonators provide a large boost of sensitivity for small samples. They can be manufactured lithographically to a wide range of target parameters. The coupler between the resonator and the microwave feedline can be integrated into this design. To optimize the coupling and to compensate manufacturing tolerances, it is sometimes desirable to have a tuning element available that can be adjusted when the resonator is connected to the spectrometer. This paper presents a simple design that allows one to bring undercoupled resonators into the condition for critical coupling. In addition, it also reduces radiation losses and thereby increases the quality factor and the sensitivity of the resonator

  20. Radiation effects and radiation risks

    International Nuclear Information System (INIS)

    Lengfelder, E.; Forst, D.; Feist, H.; Pratzel, H.

    1988-01-01

    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 [de

  1. Deflection of atomic beams with isotope separation by optical resonance radiation using stimulated emission and the ac stark effect

    International Nuclear Information System (INIS)

    Bjorkholm, J.E.; Liao, P.F.H.

    1977-01-01

    Improved atomic beam deflection and improved isotope separation, even in vapors, is proposed by substituting the A.C. Stark effect for the baseband chirp of the pushing beam in the prior proposal by I. Nebenzahl et al., Applied Physics Letters, Vol. 25, page 327 (September 1974). The efficiency inherent in re-using the photons as in the Nebenzahl et al proposal is retained; but the external frequency chirpers are avoided. The entire process is performed by two pulses of monochromatic coherent light, thereby avoiding the complication of amplifying frequency-modulated light pulses. The A.C. Stark effect is provided by the second beam of coherent monochromatic light, which is sufficiently intense to chirp the energy levels of the atoms or isotopes of the atomic beam or vapor. Although, in general, the A.C. Stark effect will alter the isotope shift somewhat, it is not eliminated. In fact, the appropriate choice of frequencies of the pushing and chirping beams may even relax the requirements with respect to the isotope absorption line shift for effective separation. That is, it may make the isotope absorption lines more easily resolvable

  2. On the contribution of circumferential resonance modes in acoustic radiation force experienced by cylindrical shells

    Science.gov (United States)

    Rajabi, Majid; Behzad, Mehdi

    2014-10-01

    A body insonified by a constant (time-varying) intensity sound field is known to experience a steady (oscillatory) force that is called the steady-state (dynamic) acoustic radiation force. Using the classical resonance scattering theorem (RST) which suggests the scattered field as a superposition of a resonance field and a background (non-resonance) component, we show that the radiation force acting on a cylindrical shell may be synthesized as a composition of three components: background part, resonance part and their interaction. The background component reveals the pure geometrical reflection effects and illustrates a regular behavior with respect to frequency, while the others demonstrate a singular behavior near the resonance frequencies. The results illustrate that the resonance effects associated to partial waves can be isolated by the subtraction of the background component from the total (steady-state or dynamic) radiation force function (i.e., residue component). In the case of steady-state radiation force, the components are exerted on the body as static forces. For the case of oscillatory amplitude excitation, the components are exerted at the modulation frequency with frequency-dependant phase shifts. The results demonstrate the dominant contribution of the non-resonance component of dynamic radiation force at high frequencies with respect to the residue component, which offers the potential application of ultrasound stimulated vibro-acoustic spectroscopy technique in low frequency resonance spectroscopy purposes. Furthermore, the proposed formulation may be useful essentially due to its intrinsic value in physical acoustics. In addition, it may unveil the contribution of resonance modes in the dynamic radiation force experienced by the cylindrical objects and its underlying physics.

  3. Electronic modulation of infrared radiation in graphene plasmonic resonators.

    Science.gov (United States)

    Brar, Victor W; Sherrott, Michelle C; Jang, Min Seok; Kim, Seyoon; Kim, Laura; Choi, Mansoo; Sweatlock, Luke A; Atwater, Harry A

    2015-05-07

    All matter at finite temperatures emits electromagnetic radiation due to the thermally induced motion of particles and quasiparticles. Dynamic control of this radiation could enable the design of novel infrared sources; however, the spectral characteristics of the radiated power are dictated by the electromagnetic energy density and emissivity, which are ordinarily fixed properties of the material and temperature. Here we experimentally demonstrate tunable electronic control of blackbody emission from graphene plasmonic resonators on a silicon nitride substrate. It is shown that the graphene resonators produce antenna-coupled blackbody radiation, which manifests as narrow spectral emission peaks in the mid-infrared. By continuously varying the nanoresonator carrier density, the frequency and intensity of these spectral features can be modulated via an electrostatic gate. This work opens the door for future devices that may control blackbody radiation at timescales beyond the limits of conventional thermo-optic modulation.

  4. An exploration in acoustic radiation force experienced by cylindrical shells via resonance scattering theory.

    Science.gov (United States)

    Rajabi, Majid; Behzad, Mehdi

    2014-04-01

    In nonlinear acoustic regime, a body insonified by a sound field is known to experience a steady force that is called the acoustic radiation force (RF). This force is a second-order quantity of the velocity potential function of the ambient medium. Exploiting the sufficiency of linear solution representation of potential function in RF formulation, and following the classical resonance scattering theorem (RST) which suggests the scattered field as a superposition of the resonant field and a background (non-resonant) component, we will show that the radiation force is a composition of three components: background part, resonant part and their interaction. Due to the nonlinearity effects, each part contains the contribution of pure partial waves in addition to their mutual interaction. The numerical results propose the residue component (i.e., subtraction of the background component from the RF) as a good indicator of the contribution of circumferential surface waves in RF. Defining the modal series of radiation force function and its components, it will be shown that within each partial wave, the resonance contribution can be synthesized as the Breit-Wigner form for adequately none-close resonant frequencies. The proposed formulation may be helpful essentially due to its inherent value as a canonical subject in physical acoustics. Furthermore, it may make a tunnel through the circumferential resonance reducing effects on radiation forces. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Effects of thermal annealing on the radiation produced electron paramagnetic resonance spectra of bovine and equine tooth enamel: Fossil and modern

    Science.gov (United States)

    Weeks, Robert A.; Bogard, James S.; Elam, J. Michael; Weinand, Daniel C.; Kramer, Andrew

    2003-06-01

    The concentration of stable radiation-induced paramagnetic states in fossil teeth can be used as a measure of sample age. Temperature excursions >100 °C, however, can cause the paramagnetic state clock to differ from the actual postmortem time. We have heated irradiated enamel from both fossilized bovid and modern equine (MEQ) teeth for 30 min in 50 °C increments from 100 to 300 °C, measuring the electron paramagnetic resonance (EPR) spectrum after each anneal, to investigate such effects. Samples were irradiated again after the last anneal, with doses of 300-1200 Gy from 60Co photons, and measured. Two unirradiated MEQ samples were also annealed for 30 min at 300 °C, one in an evacuated EPR tube and the other in a tube open to the atmosphere, and subsequently irradiated. The data showed that hyperfine components attributed to the alanine radical were not detected in the irradiated MEQ sample until after the anneals. The spectrum of the MEQ sample heated in air and then irradiated was similar to that of the heat treated fossil sample. We conclude that the hyperfine components are due to sample heating to temperatures/times >100 °C/30 min and that similarities between fossil and MEQ spectra after the 300 °C/30 min MEQ anneal are also due to sample heating. We conclude that the presence of the hyperfine components in spectra of fossil tooth enamel indicate that such thermal events occurred either at the time of death, or during the postmortem history.

  6. Form factors and radiation widths of the giant multipole resonances

    International Nuclear Information System (INIS)

    Denisov, V.Yu.

    1990-01-01

    Simple analytic relations for the form factors of inelastic electron scattering in the Born approximation and radiation widths of the isovector and isoscalar giant multipole resonances are derived. The dynamic relationship between the volume and surface density vibrations were taken into account in this calculation. The form factors in the Born approximation were found to be in satisfactory agreement with experimental data in the region of small transferred momenta. The radiation widths of isoscalar multipole resonances increase when the number of nucleons increase as A 1/3 , and for isovector resonances this dependence has the form f(A)A 1/3 , where f(A) is a slowly increasing function of A. Radiation widths well fit the experimental data

  7. Synchrotron radiation resonance Raman spectroscopy (SR3S)

    International Nuclear Information System (INIS)

    Hester, R.E.

    1979-01-01

    The use of normal Raman spectroscopy and resonance Raman spectroscopy to study the structure of molecular species and the nature of their chemical bonds is discussed. The availability of a fully tunable radiation source (the Synchrotron Radiation Source) extending into the ultraviolet raises the possibility of using synchrotron radiation resonance Raman spectroscopy as a sensitive and specific analytical probe. The pulsed nature of the SRS beam may be exploited for time-resolved resonance Raman spectroscopy and its high degree of polarization could be very helpful in the interpretation of spectra. The possibilities are considered under the headings: intensity requirements and comparison with other sources; some applications (e.g. structure of proteins; study of iron-porphyrin unit; study of chlorophylls). (U.K.)

  8. Active Radiative Thermal Switching with Graphene Plasmon Resonators.

    Science.gov (United States)

    Ilic, Ognjen; Thomas, Nathan H; Christensen, Thomas; Sherrott, Michelle C; Soljačić, Marin; Minnich, Austin J; Miller, Owen D; Atwater, Harry A

    2018-03-27

    We theoretically demonstrate a near-field radiative thermal switch based on thermally excited surface plasmons in graphene resonators. The high tunability of graphene enables substantial modulation of near-field radiative heat transfer, which, when combined with the use of resonant structures, overcomes the intrinsically broadband nature of thermal radiation. In canonical geometries, we use nonlinear optimization to show that stacked graphene sheets offer improved heat conductance contrast between "ON" and "OFF" switching states and that a >10× higher modulation is achieved between isolated graphene resonators than for parallel graphene sheets. In all cases, we find that carrier mobility is a crucial parameter for the performance of a radiative thermal switch. Furthermore, we derive shape-agnostic analytical approximations for the resonant heat transfer that provide general scaling laws and allow for direct comparison between different resonator geometries dominated by a single mode. The presented scheme is relevant for active thermal management and energy harvesting as well as probing excited-state dynamics at the nanoscale.

  9. Radiative decays of resonances on the lattice

    International Nuclear Information System (INIS)

    Agadjanov, Andria; Bernard, Véronique; Meißner, Ulf-G.; Rusetsky, Akaki

    2016-01-01

    We discuss a generalization of the Lüscher approach to the calculation of the matrix elements of the unstable states. A theoretical framework for the lattice extraction of the ΔNγ* transition form factors is formulated. The procedure to measure the form factors at the resonance pole is given. The current theoretical progress on the B → K*γ* decays is briefly summarized

  10. Interaction of a parametric transducer with a resonant bar gravitational radiation detector

    International Nuclear Information System (INIS)

    Linthorne, N.P.; Veitch, P.J.; Blair, D.G.

    1990-01-01

    It is shown that a microwave parametric transducer for a resonant bar gravitational radiation antenna can achieve high electromechanical coupling without degrading the acoustic Q of the antenna. The reactive coupling of the transducer to the antenna leads to both cold-damping and modification of the antenna's resonant frequency. These effects are examined in a 1.5 tonne niobium resonant bar antenna. At low coupling the observed behaviour is found to be in good agreement with theory. At higher coupling, the behaviour is complicated by other effects. We discuss how these parametric effects may be used to advantage when suitably controlled. (author)

  11. Space radiation effects

    International Nuclear Information System (INIS)

    Li Shiqing; Yan Heping

    1995-01-01

    The authors briefly discusses the radiation environment in near-earth space and it's influences on material, and electronic devices using in space airship, also, the research developments in space radiation effects are introduced

  12. Radiation effects in space

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1986-01-01

    The paper discusses the radiation environment in space that astronauts are likely to be exposed to. Emphasis is on proton and HZE particle effects. Recommendations for radiation protection guidelines are presented

  13. The effect of magnetic field strength on the time evolution of high energy bremsstrahlung radiation created by an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ropponen, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)], E-mail: tommi.ropponen@phys.jyu.fi; Tarvainen, O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Jones, P.; Peura, P.; Kalvas, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); Suominen, P. [Prizztech Ltd/Magnet Technology Centre, Tiedepuisto 4, FI-28600 Pori (Finland); Koivisto, H.; Arje, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)

    2009-03-11

    An electron cyclotron resonance (ECR) ion source is one of the most used ion source types for high charge state heavy ion production. In ECR plasma the electrons are heated by radio frequency microwaves in order to provide ionization of neutral gases. As a consequence, ECR heating also generates very high electron energies (up to MeV region) which can produce a vast amount of bremsstrahlung radiation causing problems with radiation shielding and heating superconducting cryostat of an ECR ion source. To gain information about the time evolution of the electron energies in ECR plasma radial bremsstrahlung measurements were performed. JYFL 14 GHz ECR ion source was operated in pulsed mode and time evolution measurements were done with different axial magnetic field strengths with oxygen and argon plasmas. Bremsstrahlung data were analyzed with a time interval of 2 ms yielding information at unprecedented detail about the time evolution of high energy bremsstrahlung radiation from an ECR ion source. It was observed, for example, that reaching the steady state phase of the plasma bremsstrahlung requires several hundred milliseconds and the steady state time can be different with different gases.

  14. Resonance Raman Spectroscopy of Free Radicals Produced by Ionizing Radiation

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter

    1984-01-01

    Applications of time-resolved resonance Raman spectroscopy to the study of short-lived free radicals produced by ionizing radiation are briefly reviewed. Potential advantages and limitations of this technique are discussed in the light of given examples. The reduction of p-nitrobenzylchloride and......Applications of time-resolved resonance Raman spectroscopy to the study of short-lived free radicals produced by ionizing radiation are briefly reviewed. Potential advantages and limitations of this technique are discussed in the light of given examples. The reduction of p......-nitrobenzylchloride and subsequent formation of the p-nitrobenzyl radical and the reaction of p-nitrotoluene with O– are studied by resonance Raman and optical absorption spectroscopy....

  15. Biological radiation effects

    International Nuclear Information System (INIS)

    Gomes, R.A.

    1976-01-01

    The stages of processes leading to radiation damage are studied, as well as, the direct and indirect mechanics of its production. The radiation effects on nucleic acid and protein macro moleculas are treated. The physical and chemical factors that modify radiosensibility are analysed, in particular the oxygen effects, the sensibilization by analogues of nitrogen bases, post-effects, chemical protection and inherent cell factors. Consideration is given to restoration processes by excision of injured fragments, the bloching of the excision restoration processes, the restoration of lesions caused by ionizing radiations and to the restoration by genetic recombination. Referring to somatic effects of radiation, the early ones and the acute syndrome of radiation are discussed. The difference of radiosensibility observed in mammalian cells and main observable alterations in tissues and organs are commented. Referring to delayed radiation effects, carcinogeneses, alterations of life span, effects on growth and development, as well as localized effects, are also discussed [pt

  16. Biological effects of radiation

    International Nuclear Information System (INIS)

    2013-01-01

    This fourth chapter presents: cell structure and metabolism; radiation interaction with biological tissues; steps of the production of biological effect of radiation; radiosensitivity of tissues; classification of biological effects; reversibility, transmissivity and influence factors; pre-natal biological effects; biological effects in therapy and syndrome of acute irradiation

  17. Dosimetry of ionizing radiations by Electron paramagnetic resonance; Dosimetria de radiaciones ionizantes por resonancia paramagnetica electronica

    Energy Technology Data Exchange (ETDEWEB)

    Azorin N, J [UAM-I, Av. San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico)

    2005-07-01

    In this work, some historical and theoretical aspects about the Electron Paramagnetic Resonance (EPR), its characteristics, the resonance detection, the paramagnetic species, the radiation effects on inorganic and organic materials, the diagrams of the instrumentation for the EPR detection, the performance of an EPR spectrometer, the coherence among EPR and dosimetry and, practical applications as well as in the food science there are presented. (Author)

  18. Radiation effects in semiconductors

    CERN Document Server

    2011-01-01

    There is a need to understand and combat potential radiation damage problems in semiconductor devices and circuits. Written by international experts, this book explains the effects of radiation on semiconductor devices, radiation detectors, and electronic devices and components. These contributors explore emerging applications, detector technologies, circuit design techniques, new materials, and innovative system approaches. The text focuses on how the technology is being used rather than the mathematical foundations behind it. It covers CMOS radiation-tolerant circuit implementations, CMOS pr

  19. Radiative resonance couplings in γ π →π π

    Science.gov (United States)

    Hoferichter, Martin; Kubis, Bastian; Zanke, Marvin

    2017-12-01

    Studies of the reaction γ π →π π , in the context of the ongoing Primakoff program of the COMPASS experiment at CERN, give access to the radiative couplings of the ρ (770 ) and ρ3(1690 ) resonances. We provide a vector-meson-dominance estimate of the respective radiative width of the ρ3, Γρ3→πγ=48 (18 ) keV , as well as its impact on the F -wave in γ π →π π . For the ρ (770 ), we establish the formalism necessary to extract its radiative coupling directly from the residue of the resonance pole by analytic continuation of the γ π →π π amplitude to the second Riemann sheet, without any reference to the vector-meson-dominance hypothesis.

  20. Radiation Therapy Side Effects

    Science.gov (United States)

    Radiation therapy has side effects because it not only kills or slows the growth of cancer cells, it can also affect nearby healthy cells. Many people who get radiation therapy experience fatigue. Other side effects depend on the part of the body that is being treated. Learn more about possible side effects.

  1. Magnetic resonance: safety measures and biological effects

    International Nuclear Information System (INIS)

    Gordillo, I.; Lafuente, J.; Fernandez, C.; Barbero, M.J.; Cascon, E.

    1997-01-01

    The biological effects of electromagnetic fields is currently a subject of great controversy. For this reason, magnetic resonance imaging (MRI) and spectroscopy are constantly under investigation. The source of the risk in MRI is associated with the three types of electromagnetic radiation to which the patient is exposed: the static magnetic field, variable (gradient) magnetic fields and radiofrequency fields. Each is capable of producing significant biological effects when employed at sufficient intensity. Patients exposed to risk sources are those situated within the lines of force of the magnetic field, ellipsoid lines that are arranged around the magnet, representing the strength of the surrounding field. To date, at the intensity normally utilized in MRI(<2T) and respecting the field limit recommendations established by the US Food and Drug Administration (FDA) for clinical use of this technique no adverse secondary biological effects have been reported. The known biological effects and other possible secondary effects are reviewed, and the recommended safety measures are discussed. (Author)

  2. Radiation effects on polyaniline

    International Nuclear Information System (INIS)

    Oki, Yuichi; Kondo, Kenjiro; Suzuki, Takenori; Numajiri, Masaharu; Miura, Taichi; Doi, Shuji; Ohnishi, Toshihiro.

    1992-01-01

    Effects of γ-irradiation on electrical conductivity of polyaniline were investigated. A drastic increase of the conductivity due to radiation-induced doping was observed in combined systems of polyaniline films and halogen-containing polymers. This effect can be applied to measure an integrated radiation dose. (author)

  3. Radiation effects in space

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1987-07-01

    As more people spend more time in space, and the return to the moon and exploratory missions are considered, the risks require continuing examination. The effects of microgravity and radiation are two potential risks in space. These risks increase with increasing mission duration. This document considers the risk of radiation effects in space workers and explorers. 17 refs., 1 fig., 4 tabs

  4. Selective reflection of resonance radiation from excited media

    International Nuclear Information System (INIS)

    Veklenko, B.A.; Gusarov, R.B.; Sherkunov, Yu.B.

    1998-01-01

    According to quantum electrodynamics, the cross section for resonant scattering of radiation on an aggregate of excited atoms can be written as a sum of positive definite terms. This type of structure is not consistent with the Fresnel formulas for the reflection coefficient of radiation from thermally excited media. The difference shows up on a macroscopic level and indicates that semiclassical radiation theory cannot be used. A study of the correlation between elastic scattering and stimulated emission processes clarifies the reason for the discrepancies. The resulting singularities require summing of Feynman diagrams which appear beginning in the sixth order of perturbation theory. A lower bound estimate for the reflection coefficient from a plane layer is given, including processes which violate the statistics of radiation. The contribution of stimulated emission processes caused by the initially scattered photon are examined specifically. An experiment is proposed which would settle the choice of theories

  5. Radiation effects and radioprotectors

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, R.K., E-mail: dr_rajendra_purohit@yahoo.co.in [Radiation Biology Laboratory, Department of Zoology, Govt. Dungar College, Bikaner (India); Bugalia, Saroj [Department of Zoology, S.K. Kalyan College, Sikar (India); Dakshene, Monika [Department of Chemistry, Govt. College, Kota (India)

    2012-07-01

    Radiation exposure causes damage to biological systems and these damages are mediated by the generation of free radicals and reactive oxygen species targeting vital cellular components such as DNA and membranes. DNA repair systems and the endogenous cellular biochemical defense mechanisms against reactive oxygen species and antioxidants enzymes like reduced Glutathione (GSH), Superoxide dismutase, Glutathione peroxidase catalase etc. fail upon exposures to higher as well as chronic radiation doses leading to alterations in cell functions, cell death or mutations. Radioprotectors prevent these alterations and protect cells and tissues from the deleterious effects of radiations. Radioprotectors are of great importance due to their possible and potential application during planned radiation exposures such as radiotherapy, diagnostic scanning, clean up operations in nuclear accidents, space expeditions etc. and Unplanned radiations exposures such as accidents in nuclear industry, nuclear terrorism, natural background radiation etc. Many of the available synthetic radioprotectors are toxic to mammalian system at doses required to be effective as radioprotector. Increasing uses of ionizing radiation have drawn the attention of many radiobiologists towards their undesired side effects produced in various tissues and for modifying them to facilitate the beneficial uses of radiation. Modification of radiation response is obtained by means of chemical substances that can significantly decrease the magnitude of response when present in a biological system during irradiation. Radioprotectors are chemicals that modify a cell's response to radiation. Radioprotectors are drugs that protect normal (non cancerous) cells from the damage caused by radiation therapy. These agents promote the repair of normal cells that are exposed to radiation. Various chemicals, like Cysteamine, MPG , WR-2721 have been tested for the protection against harmful effects of radiation. These radio

  6. Radiation effects and radioprotectors

    International Nuclear Information System (INIS)

    Purohit, R.K.; Bugalia, Saroj; Dakshene, Monika

    2012-01-01

    Radiation exposure causes damage to biological systems and these damages are mediated by the generation of free radicals and reactive oxygen species targeting vital cellular components such as DNA and membranes. DNA repair systems and the endogenous cellular biochemical defense mechanisms against reactive oxygen species and antioxidants enzymes like reduced Glutathione (GSH), Superoxide dismutase, Glutathione peroxidase catalase etc. fail upon exposures to higher as well as chronic radiation doses leading to alterations in cell functions, cell death or mutations. Radioprotectors prevent these alterations and protect cells and tissues from the deleterious effects of radiations. Radioprotectors are of great importance due to their possible and potential application during planned radiation exposures such as radiotherapy, diagnostic scanning, clean up operations in nuclear accidents, space expeditions etc. and Unplanned radiations exposures such as accidents in nuclear industry, nuclear terrorism, natural background radiation etc. Many of the available synthetic radioprotectors are toxic to mammalian system at doses required to be effective as radioprotector. Increasing uses of ionizing radiation have drawn the attention of many radiobiologists towards their undesired side effects produced in various tissues and for modifying them to facilitate the beneficial uses of radiation. Modification of radiation response is obtained by means of chemical substances that can significantly decrease the magnitude of response when present in a biological system during irradiation. Radioprotectors are chemicals that modify a cell's response to radiation. Radioprotectors are drugs that protect normal (non cancerous) cells from the damage caused by radiation therapy. These agents promote the repair of normal cells that are exposed to radiation. Various chemicals, like Cysteamine, MPG , WR-2721 have been tested for the protection against harmful effects of radiation. These radio

  7. Man and radiation effects

    International Nuclear Information System (INIS)

    Rausch, L.

    1982-01-01

    The book describes the effects of ionizing radiation on man in a simple, popular, detailed and generally valid manner and gives a comprehensive picture of the concepts, elements, principles of function, and perspectives of medical radiobiology. Radiobiology in general is explained, and its application in research on the causes of radiolesions and radiation diseases as well as a radiotherapy and radiation protection is discussed in popular form. (orig./MG) [de

  8. Biological radiation effects

    International Nuclear Information System (INIS)

    Kiefer, J.

    1989-01-01

    The book covers all aspects of biological radiation effects. The physical basis is dealt with in some detail, and the effects at the subcellular and the cellular level are discussed, taking into account modern developments and techniques. The effects on the human organism are reviewed, both from the point of view of applications in medicine as well as with regard to radiation hazards (teratogenic, gonadal and carcinogenic effects)

  9. Analysis and characterization. Nuclear resonant scattering with the synchrotron radiation

    International Nuclear Information System (INIS)

    Ruffer, R.; Teillet, J.

    2003-01-01

    The nuclear resonant scattering using the synchrotron radiation combines the uncommon properties of the Moessbauer spectroscopy and those of the synchrotron radiation. Since its first observation in 1984, this technique and its applications have been developed rapidly. The nuclear resonant scattering is now a standard technique for all the synchrotron radiation sources of the third generation. As the Moessbauer spectroscopy, it is a method of analysis at the atomic scale and a non destructive method. It presents the advantage not to require the use of radioactive sources of incident photons which can be difficult to make, of a lifetime which can be short and of an obviously limited intensity. The current applications are the hyperfine spectroscopy and the structural dynamics. In hyperfine spectroscopy, the nuclear resonant scattering can measure the same size than the Moessbauer spectroscopy. Nevertheless, it is superior in the ranges which exploit the specific properties of the synchrotron radiation, such as the very small samples, the monocrystals, the measures under high pressures, the geometry of small angle incidence for surfaces and multilayers. The structural dynamics, in a time scale of the nanosecond to the microsecond can be measured in the temporal scale. Moreover, the nuclear inelastic scattering gives for the first time a tool which allows to have directly the density of states of phonons and then allow to deduce the dynamical and thermodynamical properties of the lattice. The nuclear resonant scattering technique presented here, which corresponds to the Moessbauer spectroscopy technique (SM), is called 'nuclear forward scattering' (NFS). Current applications in physics and chemistry are develop. The NFS is compared to the usual SM technique in order to reveal its advantages and disadvantages. (O.M.)

  10. Transverse resonance-radiation pressure on atomic beams and the influence of fluctuations

    International Nuclear Information System (INIS)

    Bjorkholm, J.E.; Freeman, R.R.; Ashkin, A.; Pearson, D.B.

    1979-01-01

    We have experimentally demonstrated that a beam of neutral sodium atoms can be focused to a spot diameter of approx. 50 μ using the transverse dipole resonance-radiation pressure exerted by a 40 mW laser beam. Simple analysis shows that in some cases the spot sizes are limited by the random fluctuations of the spontaneous radiation pressure; with 1 W of laser power, spot sizes less than 10 μ should be attainable. The effects of heating by spontaneous scattering can have important detrimental effects in other applications of resonance - radiation pressure on atoms, such as the slowing or guiding of atoms. Consideration of heating effects is of paramount importance in the design of optical traps for neutral atoms. (KBE)

  11. Mode coupling in terahertz metamaterials using sub-radiative and super-radiative resonators

    International Nuclear Information System (INIS)

    Qiao, Shen; Zhang, Yaxin; Zhao, Yuncheng; Xu, Gaiqi; Sun, Han; Yang, Ziqiang; Liang, Shixiong

    2015-01-01

    We theoretically and experimentally explored the electromagnetically induced transparency (EIT) mode-coupling in terahertz (THz) metamaterial resonators, in which a dipole resonator with a super-radiative mode is coupled to an inductance-capacitance resonator with a sub-radiative mode. The interference between these two resonators depends on the relative spacing between them, resulting in a tunable transparency window in the absorption spectrum. Mode coupling was experimentally demonstrated for three spacing dependent EIT metamaterials. Transmittance of the transparency windows could be either enhanced or suppressed, producing different spectral linewidths. These spacing dependent mode-coupling metamaterials provide alternative ways to create THz devices, such as filters, absorbers, modulators, sensors, and slow-light devices

  12. Biophysical radiation effects

    International Nuclear Information System (INIS)

    Fidorra, J.

    1982-07-01

    The biological effectiveness of ionizing radiation is based upon the absorption of energy in molecular structures of a cell. Because of the quantum nature of radiation large fluctuations of energy concentration in subcellulare regions has to be considered. In addition both the spatial distribution of a sensitive molecular target and cellulare repair processes has to be taken into consideration for an assessment of radiation action. In radiation protection the difference between the quality factor and the Relative Biological Effectiveness has a fundamental meaning and will be discussed in more detail. The present report includes a short review on some relevant models on radiation action and a short discussion on effects of low dose irradiation. (orig.) [de

  13. Phototoxic effect of conjugates of plasmon-resonance nanoparticles with indocyanine green dye on Staphylococcus aureus induced by IR laser radiation

    International Nuclear Information System (INIS)

    Tuchina, E S; Tuchin, Valerii V; Khlebtsov, B N; Khlebtsov, Nikolai G

    2011-01-01

    The effect of IR laser radiation (λ = 805 - 808 nm) on the bacteria of the strain Staphylococcus aureus 209 P, incubated in indocyanine green solutions, is studied, as well as that of colloid gold nanoshells, nanocages and their conjugates with indocyanine green. It is found that the S. aureus 209 P cells are equally subjected to the IR laser radiation (λ = 805 nm) after preliminary sensitisation with indocyanine green and gold nanoparticles separately and with conjugates of nanoparticles and indocyanine green. The enhancement of photodynamic and photothermal effects by 5 % is observed after 30 min of laser illumination (λ = 808 nm) of bacteria, treated with conjugates of indocyanine green and nanocages. (optical technologies in biophysics and medicine)

  14. Radiation effects in gases

    International Nuclear Information System (INIS)

    Leonhardt, J.W.

    1985-01-01

    Problems in the studies of radiation effects in gases are discussed. By means of ionization- excitation- and electron-capture yields various applications are characterized: ionization detectors, X-ray detectors, radionuclide battery, and radiation-induced chemical gas-phase reactions. Some new results of basic research in respect to the SO 2 oxidation are discussed. (author)

  15. Effects of ionizing radiations

    International Nuclear Information System (INIS)

    Gaussens, G.

    1984-08-01

    After recalling radiation-matter interaction, influence on radiation effects of chemical composition, structure, irradiation atmosphere, dose rate, temperature of organic materials and evolution of electrical, mechanical and physical properties are reviewed. Then behaviour under irradiation of main organic materials: elastomers, thermoplastics, thermosetting plastics, oils and paints are examined. 68 refs [fr

  16. Radiation-induced polymerization and radiation effect on polymers

    International Nuclear Information System (INIS)

    Seguchi, Tadao

    1977-12-01

    The processes of radiation-induced polymerization of monomers and also radiation effects on polymers have been studied by instrumental analyses of electron spin resonance (ESR), nuclear magnetic resonance (NMR) and electron microscopy. In radiation-induced polymerization, graft-copolymerization and absorbed state polymerization were taken up. For graft-copolymerization, monomers such as methylmethacrylate and butadiene were made to react with irradiated polyethylene, and behaviors of the initiating radicals and propagating radicals were followed under the reaction by ESR. For absorbed state polymerization, acrylonitrile/zeolite and methylmethacrylate/zeolite were chosen. Absorbed monomers were irradiated at 77 0 K and polymerized at room temperature. Active species and the concentrations were measured by ESR and the yields of polymer were observed by NMR. In radiation effect on polymers, polyvinylfluoride, polyvinylidenfluoride and polytetrafluoroethylene were taken up. Active species trapped in the polymer matrixes were identified and decay and reactivity of the species were also studied. On the basis of information from the electron microscopy and x-ray analysis, radiation effects on these polymers are described. In polytetrafluoroethylene produced by radiation polymerization, the relation between morphology and polymerization conditions and also the process of crystallization during polymerization were studied. (auth.)

  17. ISR effects for resonant Higgs production at future lepton colliders

    Directory of Open Access Journals (Sweden)

    Mario Greco

    2016-12-01

    Full Text Available We study the effects of the initial state radiation on the s-channel Higgs boson resonant production at μ+μ− and e+e− colliders by convoluting with the beam energy spread profile of the collider and the Breit–Wigner resonance profile of the signal. We assess their impact on both the Higgs signal and SM backgrounds for the leading decay channels h→bb¯, WW⁎. Our study improves the existing analyses of the proposed future resonant Higgs factories and provides further guidance for the accelerator designs with respect to the physical goals.

  18. Ionizing radiation, radiation sources, radiation exposure, radiation effects. Pt. 2

    International Nuclear Information System (INIS)

    Schultz, E.

    1985-01-01

    Part 2 deals with radiation exposure due to artificial radiation sources. The article describes X-ray diagnosis complete with an analysis of major methods, nuclear-medical diagnosis, percutaneous radiation therapy, isotope therapy, radiation from industrial generation of nucler energy and other sources of ionizing radiation. In conclusion, the authors attempt to asses total dose, genetically significant dose and various hazards of total radiation exposure by means of a summation of all radiation impacts. (orig./WU) [de

  19. Behavioral and Biological Effects of Resonant Electromagnetic Absorption in Rats.

    Science.gov (United States)

    1976-11-01

    for 23-550 MHz, biological phantom materials to simulate tissue properties, monopole -above-ground radiation chamber, design of a waveguide slot array...Resonant Electromagnetic Power Absorption in Rats" L T OF FTCTIF S A,’L i .LIS SFigure Pa 1 A photograiph of the monopole -above-gruund radiation...and mice without ground effects (L/2b = 3.25 where 21Tb is the "average" circumference of the animals) ........ .................... ... 20 8

  20. Relativistic effects in resonance absorption

    International Nuclear Information System (INIS)

    Drake, J.F.; Lee, Y.C.

    1976-01-01

    The role of the relativistic-electron-mass variation in the generation of plasma waves by the linear mode conversion of intense electromagnetic waves is investigated. The increase in the electron mass in high intensity regions of the mode-converted wave reduces the local plasma frequency and thereby strongly modifies the plasma-driver resonance. A spatial discontinuity in the structure of the mode-converted wave results and causes the wave to break. Under rather modest restrictions, the wave breaking resulting from these effects occurs before the wave amplitude is limited either by thermal convection or by breaking caused by previously investigated nonrelativistic effects. Consequently, the amplitude of the mode-converted plasma wave should saturate at a much lower level than previously predicted. For simplicity, the analysis is limited to the initial stages of mode conversion where the ion dynamics can be neglected. The validity of this approximation is discussed

  1. Assessment of radiation injuries: role of nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Khushu, Subhash; Rana, Poonam

    2014-01-01

    In the event of an intentional or accidental release of ionizing radiation, timely assessment of the radiation exposure is critical for the triage and to facilitate timely and optimal medical care to the effected population. In addition to mild to severe injuries to tissues and organs, radiation injury can also cause cognitive decline, depressive behavior and affective state disturbances following exposure to both high and low doses of radiation. These may be even seen without evident tissue injury within hours to days or months to years after exposure to low doses of radiation. In this study, we exploited the multi-parametric contrast of NMR/MRI and its potential to assess radiation dose absorbed and radiation sickness thereof. High resolution NMR spectroscopy experiments were conducted on urine and serum samples collected from mice irradiated (whole body and focal irradiation) with 3, 5 and 8 Gray of γ-radiation at different time points post irradiation. Irradiated mice serum and urine showed distinct metabolic phenotypes and revealed dose and time dependent clustering of irradiated groups depicting different phases of radiation sickness. Increased concentration of urine metabolites related to gut microflora and energy metabolism were observed during different phases of radiation sickness. On the other hand serum spectra reflected changes associated with lipid, energy and membrane metabolism during radiation sickness. In vivo NMR spectroscopy and Diffusion Tensor Imaging (DTI) was also performed in different regions of brain post irradiation in animal model, which showed radiation induced metabolite changes in hippocampus region. Fractional anisotropy (FA) and mean diffusivity (MD) also demonstrated dose related changes in various brain regions which corroborated well with the behavioral parameters. The results of the present work lay a scientific foundation for development of high throughput radiation bio-dosimetry. This could further be useful in development

  2. Solar radiation pressure resonances in Low Earth Orbits

    Science.gov (United States)

    Alessi, Elisa Maria; Schettino, Giulia; Rossi, Alessandro; Valsecchi, Giovanni B.

    2018-01-01

    The aim of this work is to highlight the crucial role that orbital resonances associated with solar radiation pressure can have in Low Earth Orbit. We review the corresponding literature, and provide an analytical tool to estimate the maximum eccentricity which can be achieved for well-defined initial conditions. We then compare the results obtained with the simplified model with the results obtained with a more comprehensive dynamical model. The analysis has important implications both from a theoretical point of view, because it shows that the role of some resonances was underestimated in the past, and also from a practical point of view in the perspective of passive deorbiting solutions for satellites at the end-of-life.

  3. Coherent radiation by a spherical medium of resonant atoms

    International Nuclear Information System (INIS)

    Prasad, Sudhakar; Glauber, Roy J.

    2010-01-01

    Radiation by the atoms of a resonant medium is a cooperative process in which the medium participates as a whole. In two previous papers we treated this problem for the case of a medium having slab geometry, which, under plane-wave excitation, supports coherent waves that propagate in one dimension. We extend the treatment here to the three-dimensional problem, focusing principally on the case of spherical geometry. By regarding the radiation field as a superposition of electric and magnetic multipole fields of different orders, we express it in terms of suitably defined scalar fields. The latter fields possess a sequence of exponentially decaying eigenmodes corresponding to each multipole order. We consider several examples of spherically symmetric initial excitations of a sphere. Small uniformly excited spheres, we find, tend to radiate superradiantly, while the radiation from a large sphere with an initially excited inner core exhibits temporal oscillations that result from the participation of a large number of coherently excited amplitudes in different modes. The frequency spectrum of the emitted radiation possesses a rich structure, including a frequency gap for large spheres and sharply defined and closely spaced peaks caused by the small frequency shifts and even smaller decay rates characteristic of the majority of eigenmodes.

  4. Radiation. Doses, effect, risk

    International Nuclear Information System (INIS)

    Vapirev, E.; Todorov, P.

    1994-12-01

    This book outlines in a popular form the topic of ionizing radiation impacts on living organisms. It contains data gathered by ICRP for a period of 35 years. The essential dosimetry terms and units are presented. Natural and artificial sources of ionizing radiation are described. Possible biological radiation effects and diseases as a consequence of external and internal irradiation at normal and accidental conditions are considered. An assessment of genetic risk for human populations is presented and the concept of 'acceptable risk' is discussed

  5. Self-resonance after inflation: Oscillons, transients, and radiation domination

    Science.gov (United States)

    Lozanov, Kaloian D.; Amin, Mustafa A.

    2018-01-01

    Homogeneous oscillations of the inflaton after inflation can be unstable to small spatial perturbations even without coupling to other fields. We show that for inflaton potentials ∝|ϕ |2n near |ϕ |=0 and flatter beyond some |ϕ |=M , the inflaton condensate oscillations can lead to self-resonance, followed by its complete fragmentation. We find that for nonquadratic minima (n >1 ), shortly after backreaction, the equation of state parameter, w →1 /3 . If M ≪mPl, radiation domination is established within less than an e -fold of expansion after the end of inflation. In this case self-resonance is efficient and the condensate fragments into transient, localised spherical objects which are unstable and decay, leaving behind them a virialized field with mean kinetic and gradient energies much greater than the potential energy. This end-state yields w =1 /3 . When M ˜mPl we observe slow and steady, self-resonance that can last many e -folds before backreaction eventually shuts it off, followed by fragmentation and w →1 /3 . We provide analytical estimates for the duration to w →1 /3 after inflation, which can be used as an upper bound (under certain assumptions) on the duration of the transition between the inflationary and the radiation dominated states of expansion. This upper bound can reduce uncertainties in CMB observables such as the spectral tilt ns, and the tensor-to-scalar ratio r . For quadratic minima (n =1 ), w →0 regardless of the value of M . This is because when M ≪mPl, long-lived oscillons form within an e -fold after inflation, and collectively behave as pressureless dust thereafter. For M ˜mPl, the self-resonance is inefficient and the condensate remains intact (ignoring long-term gravitational clustering) and keeps oscillating about the quadratic minimum, again implying w =0 .

  6. Radiation response of hydrated urea evaluated using 14N nuclear quadrupole resonance

    International Nuclear Information System (INIS)

    Hintenlang, D.E.

    1992-01-01

    In this paper Nitrogen-14 nuclear quadrupole resonance is utilized to detect radiation-induced changes in urea over the 0- to 300-Gy dose range. The spin-spin relaxation time exhibits a consistent change as a function of delivered dose in hydrated urea under exposure to 60 Co gamma radiation. No changes to the spin-spin relaxation time are observed in urea samples that were not hydrated. The radiation-induced changes are attributed to indirect radiation interactions with the water surrounding the urea molecules and are explained by the formation of subtle changes in the electron bonding configurations surrounding the 14 N nuclei, not major structural rearrangements. These subtle changes may provide additional insight into the effects of ionizing radiation on biological systems

  7. Handbook of radiation effects

    International Nuclear Information System (INIS)

    Holmes-Siedle, A.; Adams, L.

    1993-01-01

    This handbook is intended to serve as a tool for designers of equipment and scientific instruments in cases where they are required to ensure the survival of the equipment in radiation environments. High-technology materials, especially semiconductors and optics, tend to degrade on exposure to radiation in many different ways. Intense high-energy radiation environments are found in nuclear reactors and accelerators, machines for radiation therapy, industrial sterilization, and space. Some engineers have to build equipment which will survive a nuclear explosion from a hostile source. Proper handling of a disaster with radioactive materials requires equipment which depends utterly on semiconductor microelectronics and imaging devices. Thus the technology of radiation-tolerant electronics is an instrument for good social spheres as diverse as disaster planning and the exploration of Mars. In order to design equipment for intense environments like those described above, then degradation from high-energy irradiation must be seen as a basic design parameter. The aim of this handbook is to assist the engineer or student in that thought; to make it possible to write intelligent specifications; to offer some understanding of the complex variety of effects which occur when high-technology components encounter high-energy radiation; and to go thoroughly into the balance of choices of how to alleviate the effects and hence achieve the design aims of the project. Separate abstracts were prepared for 15 chapters of this book

  8. Biological Effects of Radiation

    International Nuclear Information System (INIS)

    Jatau, B.D.; Garba, N.N.; Yusuf, A.M.; Yamusa, Y. A.; Musa, Y.

    2013-01-01

    In earlier studies, researchers aimed a single particle at the nucleus of the cell where DNA is located. Eighty percent of the cells shot through the nucleus survived. This contradicts the belief that if radiation slams through the nucleus, the cell will die. But the bad news is that the surviving cells contained mutations. Cells have a great capacity to repair DNA, but they cannot do it perfectly. The damage left behind in these studies from a single particle of alpha radiation doubled the damage that is already there. This proved, beyond a shadow of doubt, those there biological effects occur as a result of exposure to radiation, Radiation is harmful to living tissue because of its ionizing power in matter. This ionization can damage living cells directly, by breaking the chemical bonds of important biological molecules (particularly DNA), or indirectly, by creating chemical radicals from water molecules in the cells, which can then attack the biological molecules chemically. At some extent these molecules are repaired by natural biological processes, however, the effectiveness of this repair depends on the extent of the damage. The interaction of ionizing with the human body, arising either from external sources outside the body or from internal contamination of the body by radioactive materials, leads to the biological effects which may later show up as a clinical symptoms. Basically, this formed the baseline of this research to serve as a yardstick for creating awareness about radiation and its resulting effects.

  9. Biological Effects of Ionizing Radiation

    Science.gov (United States)

    Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

    1952-04-07

    This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

  10. The effect of asymmetry on resonant tunneling

    International Nuclear Information System (INIS)

    Garcia-Calderon, G.

    1986-07-01

    Resonant tunneling experiments on multibarrier coupled heterostructures probe the quasistationary nature of the states of the corresponding one dimensional potential. This work considers the effect of asymmetric one dimensional multibarrier potentials on resonant tunneling. It is shown, by using the properties of the propagator of the system, that this effect may lead to novel resonance phenomena and affects the lifetime of the quasistationary states of the system. The above considerations are illustrated by a simple analytical solvable model. (author)

  11. Radiation-induced optic neuropathy: A magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Guy, J.; Mancuso, A.; Beck, R.; Moster, M.L.; Sedwick, L.A.; Quisling, R.G.; Rhoton, A.L. Jr.; Protzko, E.E.; Schiffman, J.

    1991-01-01

    Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain

  12. Radiative neutron capture: Hauser Feshbach vs. statistical resonances

    Energy Technology Data Exchange (ETDEWEB)

    Rochman, D., E-mail: dimitri-alexandre.rochman@psi.ch [Reactor Physics and Systems Behavior Laboratory, Paul Scherrer Institute, Villigen (Switzerland); Goriely, S. [Institut d' Astronomie et d' Astrophysique, CP-226, Université Libre de Bruxelles, 1050 Brussels (Belgium); Koning, A.J. [Nuclear Data Section, IAEA, Vienna (Austria); Uppsala University, Uppsala (Sweden); Ferroukhi, H. [Reactor Physics and Systems Behavior Laboratory, Paul Scherrer Institute, Villigen (Switzerland)

    2017-01-10

    The radiative neutron capture rates for isotopes of astrophysical interest are commonly calculated on the basis of the statistical Hauser Feshbach (HF) reaction model, leading to smooth and monotonically varying temperature-dependent Maxwellian-averaged cross sections (MACS). The HF approximation is known to be valid if the number of resonances in the compound system is relatively high. However, such a condition is hardly fulfilled for keV neutrons captured on light or exotic neutron-rich nuclei. For this reason, a different procedure is proposed here, based on the generation of statistical resonances. This novel technique, called the “High Fidelity Resonance” (HFR) method is shown to provide similar results as the HF approach for nuclei with a high level density but to deviate and be more realistic than HF predictions for light and neutron-rich nuclei or at relatively low sub-keV energies. The MACS derived with the HFR method are systematically compared with the traditional HF calculations for some 3300 neutron-rich nuclei and shown to give rise to significantly larger predictions with respect to the HF approach at energies of astrophysical relevance. For this reason, the HF approach should not be applied to light or neutron-rich nuclei. The Doppler broadening of the generated resonances is also studied and found to have a negligible impact on the calculated MACS.

  13. Effects of hypersonic field and anharmonic interactions on channelling radiation

    International Nuclear Information System (INIS)

    George, Juby; Pathak, Anand P; Goteti, L N S Prakash; Nagamani, G

    2007-01-01

    The effects of a hypersonic field on positron channelling radiation are considered. Anharmonic effects of the transverse potential induced by these longitudinal fields are incorporated and the wavefunction of the planar channelled positron is found by the solution of Dirac equation under the resonant influence of hypersound. An expression for the resonant frequency is estimated. The transition probabilities and the intensity of the channelling radiation are also calculated. It is found that the anharmonic effects change the spectral distributions considerably

  14. Radiation effects on living systems

    International Nuclear Information System (INIS)

    Hawley, N.J.

    1980-10-01

    This bibliography includes papers and reports by Atomic Energy of Canada Limited scientists concerning radiation effects on living systems. It is divided into three sections: Radiobiology, Radiation Biochemistry and Radiation Chemistry. (auth)

  15. Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel

    International Nuclear Information System (INIS)

    Khan, Rao F.H.

    2003-01-01

    This thesis deals with the advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency, and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum measurement conditions inside the EPR cavity, post-process the measured spectrum with functional simulation of dosimetric and other interfering signals, and reconstruct dose. By using this technique, retrospective gamma exposures as low as 80±30 mGy have been successfully deciphered. The notion of dose modifier was introduced in EPR biodosimetry for low dose measurements. It has been demonstrated that by using the modified zero added dose (MZAD) technique for low radiation exposures, doses in 100 mGy ranges can be easily reconstructed in teeth that were previously thought useless for EPR dosimetry. Also, the use of a dose modifier makes robust dose reconstruction possible for higher radiation exposures. The EPR dosimetry technique was also developed for tooth samples extracted from rodents, which represent small tooth sizing. EPR doses in the molars, extracted from the mice irradiated with whole body exposures, were reassessed and shown to be correct within the experimental uncertainty. The sensitivity of human tooth enamel for neutron irradiation, obtained from the 3 MV McMaster K.N. Van de Graaff accelerator, was also studied. For the first time this work has shown that the neutron sensitivity of the tooth enamel is approximately 1/10th of the equivalent gamma sensitivity. Parametric studies for neutron dose rate and neutron energy within the available range of the accelerator, showed no impact on the sensitivity of the tooth enamel. Therefore, tooth enamel can be used as a dosimeter for both neutrons

  16. Memory effects on stochastic resonance

    Science.gov (United States)

    Neiman, Alexander; Sung, Wokyung

    1996-02-01

    We study the phenomenon of stochastic resonance (SR) in a bistable system with internal colored noise. In this situation the system possesses time-dependent memory friction connected with noise via the fluctuation-dissipation theorem, so that in the absence of periodic driving the system approaches the thermodynamic equilibrium state. For this non-Markovian case we find that memory usually suppresses stochastic resonance. However, for a large memory time SR can be enhanced by the memory.

  17. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Heribanova, A.

    1995-01-01

    The basic principles and pathways of effects of ionizing radiation on living organisms and cells are outlined. The following topics are covered: effects of radiation on living matter (direct effects, radical or indirect effects, dual radiation action, and molecular biological theories); effects of radiation on cells and tissues (cell depletion, changes in the cytogenetic information, reparation mechanisms), dose-response relationship (deterministic effects, stochastic effects), and the effects of radiation on man (acute radiation sickness, acute local changes, fetus injuries, non-tumorous late injuries, malignant tumors, genetic changes). (P.A.). 3 tabs., 2 figs., 5 refs

  18. Bystander effects of radiation

    International Nuclear Information System (INIS)

    Umar, Neethu Fathima; Daniel, Nittu

    2013-01-01

    The Radiation-Induced Bystander Effect is the phenomenon in which unirradiated cells show irradiated effects due to the signals received from nearby irradiated cells. Evidence suggests that targeted cytoplasmic irradiation results in mutation in the nucleus of the hit cells. Cells that are not directly hit by an alpha particle, but are in the vicinity of one that is hit, also contribute to the genotoxic response of the cell population. When cells are irradiated, and the medium is transferred to unirradiated cells, these unirradiated cells show bystander responses when assayed for clonogenic survival and oncogenic transformation. The demonstration of a bystander effect in human tissues and, more recently, in whole organisms have clear implication of the potential relevance of the non-targeted response to human health. This effect may also contribute to the final biological consequences of exposure to low doses of radiation. The radiation-induced bystander effect represents a paradigm shift in our understanding of the radiobiological effects of ionizing radiation, in that extranuclear and extracellular events may also contribute to the final biological consequences of exposure to low doses of radiation. Multiple pathways are involved in the bystander phenomenon, and different cell types respond differently to bystander signalling. Using cDNA microarrays, a number of cellular signalling genes, including cyclooxygenase-2 (CQX-2), have been shown to be casually linked to the bystander phenomenon. The observation that inhibition of the phosphorylation of extracellular signal-related kinase (ERK) suppressed the bystander response further confirmed the important role of the mitogen-activated protein kinase (MAPK) signalling cascade in the bystander process. The cells deficient in mitochondrial DNA showed a significantly reduced response to bystander signalling, suggesting a functional role of mitochondria in the signalling process. (author)

  19. Radiation effects on superconductivity

    International Nuclear Information System (INIS)

    Brown, B.S.

    1975-01-01

    The effect of radiation on the superconducting transition temperature (T/sub c/), upper critical field (H/sub c2/), and volume-pinning-force density (F/sub p/) were discussed for the three kinds of superconducting material (elements, alloys, and compounds). 11 figures, 3 tables, 86 references

  20. Magnetic resonance in medicine occupational exposure to static magnetic field and radiofrequency radiation

    International Nuclear Information System (INIS)

    Zivkovic, D.; Hrnjak, M.; Ivanovic, C.

    1997-01-01

    Medical personnel working with magnetic resonance imaging (MRI) devices could be exposed to static magnetic (M) field, time-varying M fields and radiofrequency (RF) radiation. The aim of work was to investigate the density of magnetic flux of static magnetic field and the power density of RF radiation which appear in the working environment around the 0.5 T MRI unit in one hospital. The density of magnetic flux of static magnetic field was measured with Hall Effect Gauss meter - Magnetech (Great Britain), and the power density of RF radiation was measured with broadband isotropic meter - The Narda Microwave Corp. (USA). The results of measurement show that the density of magnetic flux of static M field on working places are below threshold limit of exposure and the intensities of RF radiation are far below maximum permissible level. (author)

  1. Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, V D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-06-01

    Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

  2. Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, V.D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-06-01

    Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

  3. Genetic effects of radiation

    International Nuclear Information System (INIS)

    Selby, P.B.

    1977-01-01

    Many of the most important findings concerning the genetic effects of radiation have been obtained in the Biology Division of Oak Ridge National Laboratory. The paper focuses on some of the major discoveries made in the Biology Division and on a new method of research that assesses damage to the skeletons of mice whose fathers were irradiated. The results discussed have considerable influence upon estimates of genetic risk in humans from radiation, and an attempt is made to put the estimated amount of genetic damage caused by projected nuclear power development into its proper perspective

  4. Spectral investigation of hot-spot and cavity resonance effects on the terahertz radiation emitted from high-Tc superconducting Bi2Sr2CaCu2O8+δ single crystal mesa structures

    Science.gov (United States)

    Kadowaki, Kazuo; Watanabe, Chiharu; Minami, Hidetoshi; Yamamoto, Takashi; Kashiwagi, Takanari; Klemm, Richard

    2014-03-01

    Terahertz (THz) electromagnetic radiation emitted from high-Tc superconducting Bi2Sr2CaCu2O8+δ mesa structures in the case of single mesa and series-connected mesas is investigated by the FTIR spectroscopic technique while observing its temperature distribution simultaneously by a SiC photoluminescence technique. Changing the bias level, sudden jumps of the hot-spot position were clearly observed. Although the radiation intensity changes drastically associated with the jump of the hot spot position, the frequency is unaffected as long as the voltage per junction is kept constant. Since the frequency of the intense radiation satisfies the cavity resonance condition, we confirmed that the cavity resonance is of primarily importance for the synchronization of whole intrinsic Josephson junctions in the mesa for high power radiation. This work was supported in part by the Grant-in-Aid for challenging Exploratory Research, the Ministry of Education, Culture, Sports, Science & Technology (MEXT).

  5. Space charge effects: tune shifts and resonances

    International Nuclear Information System (INIS)

    Weng, W.T.

    1986-08-01

    The effects of space charge and beam-beam interactions on single particle motion in the transverse degree of freedom are considered. The space charge force and the resulting incoherent tune shift are described, and examples are given from the AGS and CERN's PSB. Equations of motion are given for resonances in the presence of the space charge force, and particle behavior is examined under resonance and space charge conditions. Resonance phase space structure is described with and without space charge. Uniform and bunched beams are compared. Beam-beam forces and resonances and beam-beam detuning are described. 18 refs., 15 figs

  6. Radiation dosimetry in human bone using electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Breen, S.L.

    1995-01-01

    Accurate measurements of dose in bone are required in order to improve the dosimetry of systemic radiotherapy for osseous metastases. Bone is an integrating dosimeter which records the radiation history of the skeleton. During irradiation, electrons become trapped in the crystalline component of bone mineral (hydroxyapatite). The traps are very stable; at room temperature, emptying of the traps occurs with a half-life of many years. The population of trapped unpaired electrons is proportional to the radiation dose administered to the bone and can be measured in excised bone samples using electron paramagnetic resonance (EPR). EPR spectra of synthetic hydroxyapatite, irradiated with Co-60, were obtained at room temperature and at 77 K. At room temperature, the radiation-induced signal, with a g-value of 2.001 ± 0.001 increased linearly with absorbed dose above a lower threshold of 3 Gy, up to doses of 200 Gy. In contrast with pure hydroxyapatite, EPR spectra of excised human bone showed a broad 'native' signal, due to the organic component of bone, which masks the dosimetrically important signal. This native signal is highly variable from sample to sample and precludes the use of EPR as an absolute dosimetry technique. However, after subtraction of the background signal, irradiated human bone showed a linear response with a lower limit of measurement similar to that of synthetic hydroxyapatite. Bone is an in vivo linear dosimeter which can be exploited to develop accurate estimates of the radiation dose delivered during systemic radiotherapy and teletherapy. However, improved sensitivity of the EPR dosimetry technique is necessary before it can be applied reliably in clinical situations. (author)

  7. Analysis of average radiation widths of neutron resonances

    International Nuclear Information System (INIS)

    Malezki, H.; Popov, A.B.; Trzeciak, K.

    1982-01-01

    On the basis of the available data on parameters of neutron resonances average values of radiation widths (GITAsub(γ)) are calculated for a wide range of nuclei in the 50 upto 250 atomic weight range. Experimental values are compared with different variants of theoretical estimates of GITAsub(γ) which are reduced to the GITAsub(γ) dependence upon atomic weight A, excitation energy U and level density parameter a as GITAsub(γ)=CAsup(α)Usup(β)asup(γ). Besides, empirical values C, α, β, γ are selected satisfying the experimental data best of all. It is determined that the use of a=kA hypothesis leads to a sufficiently better agreement between all theoretical estimates of GITAsub(γ) and experimental values. It turned out that the estimations by Weisskopf, Bondarenko-Urin or with empirically chosen parameters give an approximately similar correspondence of calculated values GITAsub(γ)sup(p) to experimental data [ru

  8. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Marko, A.M.

    1981-05-01

    In this review radiation produced by the nuclear industry is placed into context with other sources of radiation in our world. Human health effects of radiation, derivation of standards and risk estimates are reviewed in this document. The implications of exposing the worker and the general population to radiation generated by nuclear power are assessed. Effects of radiation are also reviewed. Finally, gaps in our knowledge concerning radiation are identified and current research on biological effects, on environmental aspects, and on dosimetry of radiation within AECL and Canada is documented in this report. (author)

  9. Enhanced escape rate for Hg 254 nm resonance radiation in fluorescent lamps

    International Nuclear Information System (INIS)

    Lawler, James E; Raizen, Mark G

    2013-01-01

    The potential of the low-cost MAGIS isotopic separation method to improve fluorescent lamp efficacy is explored using resonance radiation transport simulations. New Hg isotopic mixes are discovered that yield escape rates for 254 nm Hg I resonance radiation equal to 117% to 122% of the rate for a natural isotopic mix under the same lamp conditions. (paper)

  10. Radiation Effects Research Foundation

    International Nuclear Information System (INIS)

    1979-01-01

    The last day of March 1978 marked the completion of the first 3 years of operation of the Radiation Effects Research Foundation in Hiroshima and Nagasaki. RERF was established on 1 April 1975 as successor to the Atomic Bomb Casualty Commission which had been in continuous operation since 1947. This record of the first 3 years of operation consists of selected reports and other documents prepared in the course of conducting the business of RERF and includes a brief history, a late radiation effects that might be conducted at RERF. The wisdom and thought given to the research program and its operation by the Scientific Council and the Board of Directors is reflected in the minutes of their meetings which are included in the Appendix. (Mori, K.)

  11. Radiation Bystander Effects Mechanism

    Directory of Open Access Journals (Sweden)

    Shokohzaman Soleymanifard

    2009-06-01

    Full Text Available Introduction: Radiation Induced Bystander Effect (RIBE which cause radiation effects in non-irradiated cells, has challenged the principle according to which radiation traversal through the nucleus of a cell is necessary for producing biological responses. What is the mechanism of this phenomenon? To have a better understanding of this rather ambiguous concept substantial number of original and reviewed article were carefully examined. Results: Irradiated cells release molecules which can propagate in cell environment and/or transmit through gap junction intercellular communication. These molecules can reach to non-irradiated cells and transmit bystander signals. In many investigations, it has been confirmed that these molecules are growth factors, cytokines, nitric oxide and free radicals like reactive oxygen species (ROS. Transmission of by stander signal to neighboring cells persuades them to produce secondary growth factors which in their turn cause further cell injuries. Some investigators suggest, organelles other than nucleus (mitochondria and cell membrane are the origin of these signals.  There is another opinion which suggests double strand breaks (DSB are not directly generated in bystander cells, rather they are due to smaller damage like single strand breaks which accumulate and end up to DSB. Although bystander mechanisms have not been exactly known, it can be confirmed that multiple mechanisms and various pathways are responsible for this effect. Cell type, radiation type, experimental conditions and end points identify the dominant mechanism. Conclusion: Molecules and pathways which are responsible for RIBE, also cause systemic responses to other non-irradiation stresses. So RIBE is a kind of systemic stress or innate immune responses, which are performed by cell microenvironment. Irradiated cells and their signals are components of microenvironment for creating bystander effects.

  12. Radiation effects in metals

    International Nuclear Information System (INIS)

    Leteurtre Jean.

    1978-01-01

    The current understanding of radiation damage in metals is reviewed, simplifying the actual complexity of the effects by considering some aspects separately. The production of point defects in metals, the primary damage state are first studied. The second part of the lecture is devoted to the evolution of this primary damage state as a function of temperature and dose: the steady state concentration of point defects, the nucleation of secondary defects and their growth are successively considered

  13. Dispersive shock mediated resonant radiations in defocused nonlinear medium

    Science.gov (United States)

    Bose, Surajit; Chattopadhyay, Rik; Bhadra, Shyamal Kumar

    2018-04-01

    We report the evolution of resonant radiation (RR) in a self-defocused nonlinear medium with two zero dispersion wavelengths. RR is generated from dispersive shock wave (DSW) front when the pump pulse is in non-solitonic regime close to first zero dispersion wavelength (ZDW). DSW is responsible for pulse splitting resulting in the generation of blue solitons when leading edge of the pump pulse hits the first ZDW. DSW also generates a red shifted dispersive wave (DW) in the presence of higher order dispersion coefficients. Further, DSW through cross-phase modulation with red shifted dispersive wave (DW) excites a localized radiation. The presence of zero nonlinearity point in the system restricts red-shift of RR and enhances the red shifting of DW. It also helps in the formation of DSW at shorter distance and squeezes the solitonic region beyond second zero dispersion point. Predicted results indicate that the spectral evolution depends on the product of Kerr nonlinearity and group velocity dispersion.

  14. Ultra-wide-band accumulation of coherent undulator synchrotron radiation in a resonating cavity

    Directory of Open Access Journals (Sweden)

    Y. H. Seo

    2011-06-01

    Full Text Available Cavity accumulation of coherent undulator synchrotron radiation emitted by a train of periodic electron bunches is investigated. Phase-matching conditions for accumulation of radiation emitted by successive bunches are analyzed and numerically confirmed. While the coherent emission of a single bunch is optimal at grazing resonance, the accumulated radiation targeted at the upper resonant frequency of the waveguide mode is found to have much broader bandwidth and higher efficiency as the resonance steps away from the grazing condition. Numerical results confirm that stimulated superradiance is responsible for the accumulated radiation.

  15. Cumulative radiation effect

    International Nuclear Information System (INIS)

    Kirk, J.; Gray, W.M.; Watson, E.R.

    1977-01-01

    In five previous papers, the concept of Cumulative Radiation Effect (CRE) has been presented as a scale of accumulative sub-tolerance radiation damage, with a unique value of the CRE describing a specific level of radiation effect. Simple nomographic and tabular methods for the solution of practical problems in radiotherapy are now described. An essential feature of solving a CRE problem is firstly to present it in a concise and readily appreciated form, and, to do this, nomenclature has been introduced to describe schedules and regimes as compactly as possible. Simple algebraic equations have been derived to describe the CRE achieved by multi-schedule regimes. In these equations, the equivalence conditions existing at the junctions between schedules are not explicit and the equations are based on the CREs of the constituent schedules assessed individually without reference to their context in the regime as a whole. This independent evaluation of CREs for each schedule has resulted in a considerable simplification in the calculation of complex problems. The calculations are further simplified by the use of suitable tables and nomograms, so that the mathematics involved is reduced to simple arithmetical operations which require at the most the use of a slide rule but can be done by hand. The order of procedure in the presentation and calculation of CRE problems can be summarised in an evaluation procedure sheet. The resulting simple methods for solving practical problems of any complexity on the CRE-system are demonstrated by a number of examples. (author)

  16. Radiation effects on microelectronics

    International Nuclear Information System (INIS)

    Gover, J.E.

    1987-01-01

    Applications of radiation-hardened microelectronics in nuclear power systems include (a) light water reactor (LWR) containment building, postaccident instrumentation that can operate through the beta and gamma radiation released in a design basis loss-of-coolant accident; (b) advanced LWR instrumentation and control systems employing distributed digital integrated circuit (IC) technology to achieve a high degree of artificial intelligence and thereby reduce the probability of operator error under accident conditions; (c) instrumentation, command, control and communication systems for space nuclear power applications that must operate during the neutron and gamma-ray core leakage environments as well as the background electron, proton, and heavy charged particle environments of space; and (d) robotics systems designed for the described functions. Advanced microelectronics offer advantages in cost and reliability over alternative approaches to instrumentation and control. No semiconductor technology is hard to all classes of radiation effects phenomena. As the effects have become better understood, however, significant progress has been made in hardening IC technology. Application of hardened microelectronics to nuclear power systems has lagged military applications because of the limited market potential of hardened instruments and numerous institutional impediments

  17. Radiation effect on implanted pacemakers

    International Nuclear Information System (INIS)

    Pourhamidi, A.H.

    1983-01-01

    It was previously thought that diagnostic or therapeutic ionizing radiation did not have an adverse effect on the function of cardiac pacemakers. Recently, however, some authors have reported damaging effect of therapeutic radiation on cardiac pulse generators. An analysis of a recently-extracted pacemaker documented the effect of radiation on the pacemaker pulse generator

  18. Radiation effects on polyethylenes

    International Nuclear Information System (INIS)

    Suzuki, T.; Oki, Y.; Numajiri, M.; Miura, T.; Kondo, K.; Tanabe, Y.; Ishiyama, M.; Ito, Y.

    1992-01-01

    Radiation effects on four kinds of polyethylenes were studied from the viewpoints of mechanical properties, free radicals and free volumes. The samples were irradiated using a cobalt 60 gamma source to give doses up to 3MGy. The degradation of mechanical strength due to gamma-irradiation was evaluated by the elongation at break and its tensile strength. Radiation induced free radicals were measured by ESR. Free volumes observed by the o-Ps component of the positron annihilation spectrum are normally the large ones located in the amorphous regions and after irradiation these are created in crystalline regions, too. The sizes and the relative numbers of free volumes were evaluated by lifetimes and intensities of a long-lived component of positronium, respectively. Using these data, the properties of polyethylenes before and after irradiation are discussed. (author)

  19. Resonant influence of a longitudinal hypersonic field on the radiation from channeled electrons

    International Nuclear Information System (INIS)

    Grigoryan, L.Sh.; Mkrtchyan, A.R.; Mkrtchyan, A.H.; Khachatryan, H.F.; Prade, H.; Wagner, W.; Piestrup, M.A.

    2001-01-01

    The wave function of a planar/axially channeled electron with energy 10 MeV≤E<<1 GeV under the influence of a longitudinal hypersonic wave excited in a single crystal is calculated. Conditions for the resonant influence of the hypersonic wave on the quantum state of the channeled electron are deduced. Expressions for the wave function that are applicable in the case of resonance are obtained. Angular and spectral distributions of the radiation intensity from the planar/axially channeled electron are also calculated. The possibility of significant amplification of channeling radiation by a hypersonic wave is substantiated. It is found that the hypersound can excite inverse radiative transitions through which the transversal energy of the channeled electron is increased. These transitions have a resonant nature and can lead to a considerable intensification of the electron channeling radiation. In the case of axial channeling, the resonance radiation is sustained also by direct radiative transitions of the electron

  20. Biological effects of ionising radiation

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    The paper reports the proceedings of a conference organised jointly by Friends of the Earth (U.K.) and Greenpeace (International). The aim of the conference was to discuss the effects of low level radiation, particularly on man, within the terms of dose/risk relationships. The topics discussed included: sources of radiation, radiation discharges from nuclear establishments, predictive modelling of radiation hazards, radiation effects at Hiroshima, low dose effects and ICRP dose limits, variation in sensitivity to radiation, and the link between childhood cancer and nuclear power. (U.K.)

  1. Electronic Paramagnetic Resonance of irradiated nails: challenges for a dosimetry in radiation accidents

    International Nuclear Information System (INIS)

    Giannoni, Ricardo A.; Rodrigues Junior, Orlando

    2014-01-01

    The purpose of this work is to characterize samples of human nails exposed to high doses of radiation, applying the technique of Electron Paramagnetic Resonance (EPR). The objective is to establish a dose response study that allow determine the absorbed dose by exposed individuals in situations of radiological accidents, in a retrospective form. Samples of human nails were collected and afterward irradiated with gamma radiation, and received dose of 20 Gy. The EPR measurement performed on the samples, before irradiation, permitted the signal identification of the components associated with effects caused by the mechanical stress during the fingernail cutting, the so-called mechanically induced signal (MIS). After the irradiation, different species of free radicals were identified, the so-called radiation induced signal (RIS). (author)

  2. Radiation-induced conductivity and high-temperature Q changes in quartz resonators

    International Nuclear Information System (INIS)

    Koehler, D.R.

    1981-01-01

    While high temperature electrolysis has proven beneficial as a technique to remove interstitial impurities from quartz, reliable indices to measure the efficacy of such a processing step are still under development. The present work is directed toward providing such an index. Two techniques have been investigated - one involves measurement of the radiation induced conductivity in quartz along the optic axis, and the second involves measurement of high temperature Q changes. Both effects originate when impurity charge compensators are released from their traps, in the first case resulting in ionic conduction and in the second case resulting in increased acoustic losses. Radiation induced conductivity measurements have been carried out with a 200 kV, 14 mA x-ray machine producing 5 rads/s. With electric fields of the order of 10 4 V/cm, the noise level in the current measuring system is equivalent to an ionic current generated by quartz impurities in the 1 ppB range. The accuracy of the high temperature ( 300 to 800 0 K) Q -1 measurement technique will be determined. A number of resonators constructed of quartz material of different impurity contents have been tested and both the radiation induced conductivity and the high temperature Q -1 results compared with earlier radiation induced frequency and resonator resistance changes. 10 figures

  3. Biological radiation effects

    International Nuclear Information System (INIS)

    Koggl, D.; Dedenkov, A.N.

    1986-01-01

    All nowadays problems of radio biology are considered: types of ionizing radiations, their interaction with material; damage of molecular structures and their reparation; reaction of cells and their recovery from radiation damage; reaction of the whole organism and its separate systems. Particular attention is given to the problems of radiation carcinogenesis and radiation hazard for man

  4. Cumulative radiation effect

    International Nuclear Information System (INIS)

    Kirk, J.; Cain, O.; Gray, W.M.

    1977-01-01

    Cumulative Radiation Effect (CRE) represents a scale of accumulative sub-tolerance radiation damage, with a unique value of the CRE describing a specific level of radiation effect. Computer calculations have been used to simplify the evaluation of problems associated with the applications of the CRE-system in radiotherapy. In a general appraisal of the applications of computers to the CRE-system, the various problems encountered in clinical radiotherapy have been categorised into those involving the evaluation of a CRE at a point in tissue and those involving the calculation of CRE distributions. As a general guide, the computer techniques adopted at the Glasgow Institute of Radiotherapeutics for the solution of CRE problems are presented, and consist basically of a package of three interactive programs for point CRE calculations and a Fortran program which calculates CRE distributions for iso-effect treatment planning. Many examples are given to demonstrate the applications of these programs, and special emphasis has been laid on the problem of treating a point in tissue with different doses per fraction on alternate treatment days. The wide range of possible clinical applications of the CRE-system has been outlined and described under the categories of routine clinical applications, retrospective and prospective surveys of patient treatment, and experimental and theoretical research. Some of these applications such as the results of surveys and studies of time optimisation of treatment schedules could have far-reaching consequences and lead to significant improvements in treatment and cure rates with the minimum damage to normal tissue. (author)

  5. Effects of background radiation

    International Nuclear Information System (INIS)

    Knox, E.G.; Stewart, A.M.; Gilman, E.A.; Kneale, G.W.

    1987-01-01

    The primary objective of this investigation is to measure the relationship between exposure to different levels of background gamma radiation in different parts of the country, and different Relative Risks for leukaemias and cancers in children. The investigation is linked to an earlier analysis of the effects of prenatal medical x-rays upon leukaemia and cancer risk; the prior hypothesis on which the background-study was based, is derived from the earlier results. In a third analysis, the authors attempted to measure varying potency of medical x-rays delivered at different stages of gestation and the results supply a link between the other two estimates. (author)

  6. Radiation effects on vasoproliferation

    International Nuclear Information System (INIS)

    Yamaura, Hirotsugu; Matsuzawa, Taiju

    1975-01-01

    The authors quantitatively examined radiation effects on vascular proliferarion, using the rat transparent chamber technique to observe the living microcirculation. We studied the process of vasoproliferation and revascularization from the surrounding pre-existing vessels into the surgically avascularized area in the chamber, by measuring the vascular lenght photographically. A hyper-vascularized zone, about 0.5 mm in with, was formed on the vascularizing frontier, the significance of which is so far not known. When the chambers were irradiated with various doses of 60 Co γ-rays, a dose dependent inhibition of vasoproliferation was observed. (auth.)

  7. Radiation effects on vasoproliferation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaura, H; Matsuzawa, T [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer

    1975-06-01

    The authors quantitatively examined radiation effects on vascular proliferarion, using the rat transparent chamber technique to observe the living microcirculation. We studied the process of vasoproliferation and revascularization from the surrounding pre-existing vessels into the surgically avascularized area in the chamber, by measuring the vascular lenght photographically. A hyper-vascularized zone, about 0.5 mm in with, was formed on the vascularizing frontier, the significance of which is so far not known. When the chambers were irradiated with various doses of /sup 60/Co ..gamma..-rays, a dose dependent inhibition of vasoproliferation was observed.

  8. Effects produced by nuclear radiation in powdery milk

    International Nuclear Information System (INIS)

    Urena N, F.; Reyes G, A.

    1999-01-01

    The objective of this work is to determine the chemical effects produced by the gamma rays and beta particles radiations on the powdery milk. This work treats on the Pre-dose analysis, sampling radiating, electron spin resonance, acidity, proteins, aminoacids, lactose, fatty acids, peroxides, as well as its experimental results. (Author)

  9. Biological radiation effects

    International Nuclear Information System (INIS)

    Sejourne, Michele.

    1977-01-01

    This work examines ionizing radiations: what they are, where they come from, their actions and consequences, finally the norms and preventive measures necessary to avoid serious contamination, whether the individual or the population in general is involved. Man has always been exposed to natural irradiation, but owing to the growing use of ionizing radiations both in medicine and in industry, not to mention nuclear tests and their use as an argument of dissuasion, the irradiation of human beings is increasing daily. Radioactive contamination does remain latent, apart from acute cases, but this is where the danger lies since the consequences may not appear until long after the irradiation. Of all biological effects due to the action of radioelements the genetic risk is one of the most important, affecting the entire population and especially the generations to come. The risk of cancer and leukemia induction plays a substantial part also since a large number of people may be concerned, depending on the mode of contamination involved. All these long-term dangers do not of course exclude the various general or local effects to which the individual alone may be exposed and which sometimes constitute a threat to life. As a result the use of ionizing radiations must be limited and should only be involved if no other process can serve instead. The regulations governing radioelements must be stringent and their application strictly supervised for the better protection of man. This protection must be not only individual but also collective since pollution exists in air, water and land passes to plants and animals and finally reaches the last link in the food chain, man [fr

  10. Radiation effects and radiation risks. 2. ed.

    International Nuclear Information System (INIS)

    Lengfelder, E.; Forst, D.; Feist, H.; Pratzel, H.G.

    1990-01-01

    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.) With 10 maps in appendix [de

  11. Resonant circular photogalvanic effect in GaN/AlGaN heterojunctions

    NARCIS (Netherlands)

    Wittmann, B.; Golub, L. E.; Danilov, S. N.; Karch, J.; Reitmaier, C.; Kvon, Z. D.; Vinh, N. Q.; van der Meer, A. F. G.; Murdin, B.; Ganichev, S. D.

    2008-01-01

    The resonant circular photogalvanic effect is observed in wurtzite (0001)-oriented GaN low-dimensional structures excited by infrared radiation. The current is induced by angular-momentum transfer of photons to the photoexcited electrons at resonant intersubband optical transitions in a GaN/AlGaN

  12. Radiative decays of the upsilon (2S) resonance

    International Nuclear Information System (INIS)

    Irion, J.

    1984-04-01

    The Crystal Ball Detector at DORIS II was used to study radiative decays of the upsilon (2S) resonance with more than twice the previously available data. The inclusive photon spectrum of hadronic upsilon (2S) decays and the exclusive channel upsilon (2S) → γγ upsilon (1S) → γγ l + l - were analyzed. In the inclusive spectrum three significant photon lines at energies of Eγ 1 = (108.2 +- 0.7 +- 4) MeV, Eγ 1 = (127.1 +- 0.8 +- 4) MeV and Eγ 3 = (160.0 +- 2.4 +- 4) MeV with branching fractions of (6.0 +- 0.7 +- 0.9)%, (6.6 +- 0.8 +- 1.0)%, (2.6 +- 0.7 +- 0.8)% respectively were measured. The lines are consistent with being transitions from the upsilon (2S) to the 3 P 2 , 3 P 1 and 3 P 0 states. In addition a line at Eγ approx. 427 MeV was observed which is interpreted as transitions from the 3 P 2 1 states to the upsilon (1S). 17 references

  13. Effects of radiation

    International Nuclear Information System (INIS)

    Masse, R.

    2006-01-01

    The medical consequences of a whole-body irradiation come from the destruction of cells and inflammatory reactions it provokes. The most sensitive organs are the tissues that actively split. The embryo is particularly sensitive, from 200 mSv for the effects on the brain development. The reproduction functions are reached for man from 2000 mSv, the ovary sensitivity is less, the oocytes do not split after the fetus life. For adult the bone marrow outrage leads to the disappearing of blood cells (4000 mSv). The doses from 6000 to 10000 mSv lead the failure of the digestive system and lung. for the upper doses every tissue is reached, particularly by the effects on cells of blood vessels. Important brain dysfunctions appear beyond 10000 mSv. As regards the delayed effects of overexposures the epidemiology brings to light sanitary consequences of the exposure of the population to the ionizing radiations and requires that all the possible factors associated for that purpose are considered. About hereditary effects, it appears that moderate acute radiation exposures of even a relatively large human population must have little impact, in spite of the rate of spontaneous congenital deformations is of the order of 6 %. For the induction of cancers, it is not observed excess for doses lower than 200 mSv for adults and 100 mSv for children (the populations studied are survival people of hiroshima and Nagasaki, patients treated by irradiation, uranium miners, children exposed to radioactive iodine after Chernobylsk accident). To simplify an expression of the risk has been fixed to 5% of induced cancer by Sv for population and 4% by Sv for workers, the different being explained by the demography and the sensitivity of the youngest age groups. As regards the low doses of radiations, a bundle of convergent epidemiological observations notices the absence of effects of the low doses rates. Biological mechanisms, notably of repair are approached, then certain accidents (Goiania

  14. Parametrically tunable soliton-induced resonant radiation by three-wave mixing

    DEFF Research Database (Denmark)

    Zhou, Binbin; Liu, Xing; Guo, Hairun

    2017-01-01

    We show that a temporal soliton can induce resonant radiation by three-wave mixing nonlinearities. This constitutes a new class of resonant radiation whose spectral positions are parametrically tunable. The experimental verification is done in a periodically poled lithium niobate crystal, where...... a femtosecond near-IR soliton is excited and resonant radiation waves are observed exactly at the calculated soliton phasematching wavelengths via the sum- and difference-frequency generation nonlinearities. This extends the supercontinuum bandwidth well into the mid IR to span 550–5000 nm, and the mid-IR edge...

  15. Effect of couplings in the resonance continuum

    International Nuclear Information System (INIS)

    Royal, J; Larson, A; Orel, A E

    2004-01-01

    Electronic coupling of two or more resonances via the electron scattering continuum is investigated. The effect of this coupling as a function of the resonance curves and autoionization widths is investigated, and the conditions for the maximum effect are determined. The theory is applied to two physical problems, the product state distribution produced by the dissociative recombination of electrons with HeH + and a one-dimensional model for ion-pair production resulting from electron collisions with H + 3 . It is found that the coupling does not affect the product state distribution in HeH + but produces a significant effect in the H + 3 model

  16. Radiation effects on living systems

    International Nuclear Information System (INIS)

    Hawley, N.J.

    1984-04-01

    This bibliography includes papers and reports by Atomic Energy of Canada Limited scientists concerning radiation effects on living systems. It is divided into three sections: Radiobiology, Radiation Biochemistry and Radiation Chemistry. It is intended that the bibliography will be updated regularly

  17. Radiation effects in optoelectronic devices

    International Nuclear Information System (INIS)

    Barnes, C.E.

    1977-03-01

    A summary is given of studies on radiation effects in light-emitting diodes, laser diodes, detectors, optical isolators and optical fibers. It is shown that the study of radiation damage in these devices can provide valuable information concerning the nature of the devices themselves, as well as methods of hardening these devices for applications in radiation environments

  18. Genetic effects of ionising radiation

    International Nuclear Information System (INIS)

    Saunders, P.A.H.

    1991-12-01

    Ionizing radiation effects on the gem cells, which can result in genetic abnormalities, are described. The basic mechanisms of radiation interactions with chromosomes, or specifically DNA, which can result in radiation induced mutation are discussed. Methods of estimating genetic risks, and some values for quantitative risk estimates are given. (U.K.). 13 refs., 2 figs., 1 tab

  19. Biological effects of particle radiation

    International Nuclear Information System (INIS)

    Sakamoto, Kiyohiko

    1988-01-01

    Conventional radiations such as photons, gamma rays or electrons show several physical or biological disadvantages to bring tumors to cure, therefore, more and more attentions is being paid to new modalitie such as fast neutrons, protons, negative pions and heavy ions, which are expected to overcome some of the defects of the conventional radiations. Except for fast neutrons, these particle radiations show excellet physical dose localization in tissue, moreover, in terms of biological effects, they demonstrate several features compared to conventional radiations, namely low oxygen enhancement ratio, high value of relative biological effectiveness, smaller cellular recovery, larger therapeutic gain factor and less cell cycle dependency in radiation sensitivity. In present paper the biological effects of particle radiations are shown comparing to the effects of conventional radiations. (author)

  20. Biology of ionizing radiation effects

    International Nuclear Information System (INIS)

    Ferradini, C.; Pucheault, J.

    1983-01-01

    The present trends in biology of ionizing radiation are reviewed. The following topics are investigated: interaction of ionizing radiations with matter; the radiolysis of water and aqueous solutions; properties of the free radicals intervening in the couples O 2 /H 2 O and H 2 O/H 2 ; radiation chemistry of biological compounds; biological effects of ionizing radiations; biochemical mechanisms involving free radicals as intermediates; applications (biotechnological applications, origins of life) [fr

  1. The biological effects of radiation

    International Nuclear Information System (INIS)

    Sykes, D.A.

    1979-01-01

    The hazards of radiations to man are briefly covered in this paper. The natural background sources of radiations are stated and their resulting doses are compared to those received voluntarily by man. The basis of how radiations cause biological damage is given and the resulting somatic effects are shown for varying magnitude of dose. Risk estimates are given for cancer induction and genetic effects are briefly discussed. Finally four case studies of radiation damage to humans are examined exemplifying the symptoms of large doses of radiations [af

  2. Issues of effective field theories with resonances

    International Nuclear Information System (INIS)

    Gegelia, J.; Japaridze, G.

    2014-01-01

    We address some issues of renormalization and symmetries of effective field theories with unstable particles - resonances. We also calculate anomalous contributions in the divergence of the singlet axial current in an effective field theory of massive SU(N) Yang-Mills fields interacting with fermions and discuss their possible relevance to the strong CP problem. (author)

  3. Radiation effects on lymphocytes

    International Nuclear Information System (INIS)

    Roser, B.

    1976-01-01

    This review of the ontogeny of lymphocyte populations concentrates on sites of production, rates of production, and the factors governing the differentiation and longevity of the various lymphocyte pools. The physiology of the lymphocyte pools is described with particular emphasis on recirculation from blood to lymph through lymphoid tissues. The separate routes of recirculation of both thymus-derived and nonthymus-derived lymphocytes and the possible anatomical sites and mechanisms of lymphocyte cooperation are discussed. Radiation effects on lymphocyte populations are divided into two sections. First, the effects of whole-body irradiation on the total lymphocyte pools are discussed including the differential effects of irradiation on T lymphocytes, B lymphocytes, lymphoblasts, and plasma cells. The differential sensitivity of various types of immune response is correlated, where possible, with the differential sensitivity of the lymphocyte types involved. Second, experimental attempts to selectively deplete discrete subpopulations of the total lymphocyte pools, e.g., recirculating cells, are briefly discussed with particular emphasis on studies on the effects of the localization of radionuclides in lymphoid tissue

  4. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Experiments with small animals, tissue cultures, and inanimate materials help with understanding the effects of ionizing radiation that occur at the molecular level and cause the gross effects observed in man. Topics covered in this chapter include the following: Radiolysis of Water; Radiolysis of Organic Compounds; Radiolysis in Cells; Radiation Exposure and Dose Units; Dose Response Curves; Radiation Effects in Animals; Factors Affecting Health Risks. 8 refs., 3 figs., 5 tabs

  5. Nonlinear effects in varactor-tuned resonators.

    Science.gov (United States)

    Everard, Jeremy; Zhou, Liang

    2006-05-01

    This paper describes the effects of RF power level on the performance of varactor-tuned resonator circuits. A variety of topologies are considered, including series and parallel resonators operating in both unbalanced and balanced modes. As these resonators were designed to produce oscillators with minimum phase noise, the initial small signal insertion loss was set to 6 dB and, hence, QL/Q0 = 1/2. To enable accurate analysis and simulation, S parameter and PSPICE models for the varactors were optimized and developed. It is shown that these resonators start to demonstrate nonlinear operation at very low power levels demonstrating saturation and lowering of the resonant frequency. On occasion squegging is observed for modified bias conditions. The nonlinear effects are dependent on the unloaded Q (Q0), the ratio of loaded to unloaded Q (QL/Q0), the bias voltage, and circuit configurations with typical nonlinear effects occurring at -8 dBm in a circuit with a loaded Q of 63 and a varactor bias voltage of 3 V. Analysis, simulation, and measurements that show close correlation are presented.

  6. Resonance integral analytical calculation considering shadowing effect

    International Nuclear Information System (INIS)

    Monteiro, M.A.M.; Martinez, A.S.

    1990-01-01

    It is presented a method for the Resonance Integral Calculation in the fuel and moderator regions, including the shadowing effect. This effect appears due to the presence of several fuel rods in a infinite moderator region. The method is based on the approximations to the J (ξ, β) function and theirs partial derivatives in relation to β. The dependence of the Resonance Integral in the J (ξ, β) comes from the rational approximation to the neutron escape probability. The final results were obtained in a very simple and fast way, and they show the good accuracy of the method. (author)

  7. Laser radiation effect on radiation-induced defects in heavy ion tracks in dielectrics

    International Nuclear Information System (INIS)

    Egorov, A.N.; Zhiryakov, B.M.; Kushin, V.V.; Lyapidevskij, V.K.; Khokhlov, N.B.

    1988-01-01

    Possibility of laser radiation resonance effect on radiation-induced defects in heavy ion tracks in dielectric materials is investigated. Absorption spectra in infrared, visible and ultraviolet ranges for cellulose nitrate samples irradiated by 6 MeV/nucleon 58 Ni ions and reactor gamma radiation are measured. Absorption spectra for irradiated and reference samples are presented. Two absorption bands λ 1 =0.33 μm (E 1 =3.9 eV) and λ 2 =0.72 μm (E 2 =1.7 eV) are detected. Etching rate decrease in a track under laser radiation effect is noticed. 3 refs.; 1 fig

  8. Effects of radiation on man

    International Nuclear Information System (INIS)

    Saunders, P.A.H.

    1981-01-01

    The available evidence on the effects of radiation on man and the predictions that have been made of possible low level effects are reviewed. Data from United Nations Scientific Committee of the Effects of Atomic Radiation (UNSCEAR) and the committee on the Biological Effects of Ionising Radiation (BEIR) is used to illustrate the acute, delayed and hereditary effects of high dose levels. The effects of low dose levels are discussed on the assumption that both somatic and hereditary effects can be predicted on the basis of linear extrapolation from high dose effects. (U.K.)

  9. Health effects of ionizing radiation

    International Nuclear Information System (INIS)

    Pathak, B.

    1989-12-01

    Ionizing radiation is energy that travels through space as electromagnetic waves or a stream of fast moving particles. In the workplace, the sources of ionizing radiation are radioactive substances, nuclear power plants, x-ray machines and nuclear devices used in medicine, research and industry. Commonly encountered types of radiation are alpha particles, beta particles and gamma rays. Alpha particles have very little penetrating power and pose a risk only when the radioactive substance is deposited inside the body. Beta particles are more penetrating than alpha particles and can penetrate the outer body tissues causing damage to the skin and the eyes. Gamma rays are highly penetrating and can cause radiation damage to the whole body. The probability of radiation-induced disease depends on the accumulated amount of radiation dose. The main health effects of ionizing radiation are cancers in exposed persons and genetic disorders in the children, grandchildren and subsequent generations of the exposed parents. The fetus is highly sensitive to radiation-induced abnormalities. At high doses, radiation can cause cataracts in the eyes. There is no firm evidence that ionizing radiation causes premature aging. Radiation-induced sterility is highly unlikely for occupational doses. The data on the combined effect of ionizing radiation and other cancer-causing physical and chemical agents are inconclusive

  10. Chemical effects of radiation

    International Nuclear Information System (INIS)

    Philips, G.O.

    1986-01-01

    Ionizing radiations initiate chemical changes in materials because of the high energy of their quanta. In water, highly reactive free radicals are produced which can initiate secondary changes of solutes, and in chemical of biological molecules in contact with the water. Free radicals can also be directly produced in irradiated medical products. Their fate can be identified and the molecular basis of radiation inactivation clarified. Methods have now been developed to protect and minimise such radiation damage. (author)

  11. Generation of linearly polarized resonant transition radiation X-ray beam

    International Nuclear Information System (INIS)

    Yajima, Kazuaki; Awata, Takaaki; Ikeda, Mitsuharu; Ikeda, Kenichi; Yogo, Akifumi; Itoh, Akio; Imanishi, Nobutsugu

    2000-01-01

    We have proposed a method to generate almost linearly polarized resonant transition radiation X rays by using a rectangular slit placed on an electron beam axis. Our calculation predicted that the linearity is 93.5% for the resonant transition radiation X-ray beam extracted through a slit of 0.5 mrad long and 0.2 mrad wide in case of 1-GeV electron beam irradiating a 7.5-μm thick Kapton foil stack. (author)

  12. Generation of linearly polarized resonant transition radiation X-ray beam

    Energy Technology Data Exchange (ETDEWEB)

    Yajima, Kazuaki; Awata, Takaaki; Ikeda, Mitsuharu; Ikeda, Kenichi; Yogo, Akifumi; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Dept. of Nuclear Engineering

    2000-03-01

    We have proposed a method to generate almost linearly polarized resonant transition radiation X rays by using a rectangular slit placed on an electron beam axis. Our calculation predicted that the linearity is 93.5% for the resonant transition radiation X-ray beam extracted through a slit of 0.5 mrad long and 0.2 mrad wide in case of 1-GeV electron beam irradiating a 7.5-{mu}m thick Kapton foil stack. (author)

  13. Dynamic nonlinear thermal optical effects in coupled ring resonators

    Directory of Open Access Journals (Sweden)

    Chenguang Huang

    2012-09-01

    Full Text Available We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple “shark fins” and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.

  14. Even-parity resonances with synchrotron radiation from Laser Excited Lithium at 1s^22p State

    Science.gov (United States)

    Huang, Ming-Tie; Wehlitz, Ralf

    2010-03-01

    Correlated many-body dynamics is still one of the unsolved fundamental problems in physics. Such correlation effects can be most clearly studied in processes involving single atoms for their simplicity.Lithium, being the simplest open shell atom, has been under a lot of study. Most of the studies focused on ground state lithium. However, only odd parity resonances can be populated through single photon (synchrotron radiation) absorption from ground state lithium (1s^22s). Lithium atoms, after being laser excited to the 1s^22p state, allow the study of even parity resonances. We have measured some of the even parity resonances of lithium for resonant energies below 64 eV. A single-mode diode laser is used to excite lithium from 1s^22s ground state to 1s^22p (^2P3/2) state. Photoions resulting from the interaction between the excited lithium and synchrotron radiation were analyzed and collected by an ion time-of-flight (TOF) spectrometer with a Z- stack channel plate detector. The Li^+ ion yield was recorded while scanning the undulator along with the monochromator. The energy scans have been analyzed regarding resonance energies and parameters of the Fano profiles. Our results for the observed resonances will be presented.

  15. Diffusion effects in undulator radiation

    Directory of Open Access Journals (Sweden)

    Ilya Agapov

    2014-11-01

    Full Text Available Quantum diffusion effects in undulator radiation in semiclassical approximation are considered. Short-term effects on the electron beam motion are discussed and it is shown that approaches based on diffusion approximation with drift-diffusion coefficients derived from undulator or bending magnet radiation spectrum, and on Poisson statistics with radiation spectrum defined by the local beding field, all lead to similar results in terms of electron energy spread for cases of practical interest. An analytical estimate of the influence of quantum diffusion on the undulator radiation spectrum is derived.

  16. Radiation effect of polyether-urethane under action of different ionizing radiation

    International Nuclear Information System (INIS)

    Huang Wei; Chen Xiaojun; Gao Xiaoling; Xu Yunshu; Fu Yibei

    2006-01-01

    The research concerns in the radiation effect of γ-ray and electron beam on polyether-urethane. The thermal property and radical intensity were determined by differential thermal gravimetric analysis and electron spin resonance. The composition and content of gas products from samples irradiated by different ionizing radiation were analyzed by gas chromatography. The action mechanism of these two radiation resources of γ-ray and electron beam are same, but the means of energy deposit is different. It results in the differences of radical intensity and the thermal property of polyether-urethane as well as its gas products from the radiation decomposition. (authors)

  17. Radiation effect on polytetrafluoroethylene

    International Nuclear Information System (INIS)

    Deng Pengyang; Zhong Xiaoguang; Sun Jiazhen

    1999-01-01

    Polytetrafluoroethylene (PTFE) has always been regarded as a typical kind of radiation degradation polymer. But, in fact, PTFE can be induced crosslinking by γ-ray or electron beam at some special conditions (free oxygen and a narrow temperature region at 335 +- 5 degree C). Compared with radiation degradiation PTFE, cosslinking PTFE owns a lot of new properties. Some articles concerning with these have been published, which will be systematically reviewed in this

  18. Radiation effects on cell membranes

    International Nuclear Information System (INIS)

    Koeteles, G.J.

    1982-01-01

    Experimental data are presented concerning the effects of relatively low doses of x radiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the manifold influence of radiation-induced membrane phenomenon on the development and regeneration of radiation injuries. (author)

  19. Radiation effects in optoelectronic devices

    International Nuclear Information System (INIS)

    Barnes, C.E.; Wiczer, J.J.

    1984-05-01

    Purpose of this report is to provide not only a summary of radiation damage studies at Sandia National Laboratories, but also of those in the literature on the components of optoelectronic systems: light emitting diodes (LEDs), laser diodes, photodetectors, optical fibers, and optical isolators. This review of radiation damage in optoelectronic components is structured according to device type. In each section, a brief discussion of those device properties relevant to radiation effects is given

  20. Dynamics of moving interacting atoms in a laser radiation field and optical size resonances

    International Nuclear Information System (INIS)

    Gadomskii, O.N.; Glukhov, A.G.

    2005-01-01

    The forces acting on interacting moving atoms exposed to resonant laser radiation are calculated. It is shown that the forces acting on the atoms include the radiation pressure forces as well as the external and internal bias forces. The dependences of the forces on the atomic spacing, polarization, and laser radiation frequency are given. It is found that the internal bias force associated with the interaction of atomic dipoles via the reemitted field may play an important role in the dynamics of dense atomic ensembles in a light field. It is shown that optical size resonances appear in the system of interacting atoms at frequencies differing substantially from transition frequencies in the spectrum of atoms. It is noted that optical size resonances as well as the Doppler frequency shift in the spectrum of interacting atoms play a significant role in the processes of laser-radiation-controlled motion of the atoms

  1. Effects of radiation; Effets des radiations

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

    2006-07-01

    The medical consequences of a whole-body irradiation come from the destruction of cells and inflammatory reactions it provokes. The most sensitive organs are the tissues that actively split. The embryo is particularly sensitive, from 200 mSv for the effects on the brain development. The reproduction functions are reached for man from 2000 mSv, the ovary sensitivity is less, the oocytes do not split after the fetus life. For adult the bone marrow outrage leads to the disappearing of blood cells (4000 mSv). The doses from 6000 to 10000 mSv lead the failure of the digestive system and lung. for the upper doses every tissue is reached, particularly by the effects on cells of blood vessels. Important brain dysfunctions appear beyond 10000 mSv. As regards the delayed effects of overexposures the epidemiology brings to light sanitary consequences of the exposure of the population to the ionizing radiations and requires that all the possible factors associated for that purpose are considered. About hereditary effects, it appears that moderate acute radiation exposures of even a relatively large human population must have little impact, in spite of the rate of spontaneous congenital deformations is of the order of 6 %. For the induction of cancers, it is not observed excess for doses lower than 200 mSv for adults and 100 mSv for children (the populations studied are survival people of hiroshima and Nagasaki, patients treated by irradiation, uranium miners, children exposed to radioactive iodine after Chernobylsk accident). To simplify an expression of the risk has been fixed to 5% of induced cancer by Sv for population and 4% by Sv for workers, the different being explained by the demography and the sensitivity of the youngest age groups. As regards the low doses of radiations, a bundle of convergent epidemiological observations notices the absence of effects of the low doses rates. Biological mechanisms, notably of repair are approached, then certain accidents (Goiania

  2. Effects of radiation; Effets des radiations

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R. [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

    2006-07-01

    The medical consequences of a whole-body irradiation come from the destruction of cells and inflammatory reactions it provokes. The most sensitive organs are the tissues that actively split. The embryo is particularly sensitive, from 200 mSv for the effects on the brain development. The reproduction functions are reached for man from 2000 mSv, the ovary sensitivity is less, the oocytes do not split after the fetus life. For adult the bone marrow outrage leads to the disappearing of blood cells (4000 mSv). The doses from 6000 to 10000 mSv lead the failure of the digestive system and lung. for the upper doses every tissue is reached, particularly by the effects on cells of blood vessels. Important brain dysfunctions appear beyond 10000 mSv. As regards the delayed effects of overexposures the epidemiology brings to light sanitary consequences of the exposure of the population to the ionizing radiations and requires that all the possible factors associated for that purpose are considered. About hereditary effects, it appears that moderate acute radiation exposures of even a relatively large human population must have little impact, in spite of the rate of spontaneous congenital deformations is of the order of 6 %. For the induction of cancers, it is not observed excess for doses lower than 200 mSv for adults and 100 mSv for children (the populations studied are survival people of hiroshima and Nagasaki, patients treated by irradiation, uranium miners, children exposed to radioactive iodine after Chernobylsk accident). To simplify an expression of the risk has been fixed to 5% of induced cancer by Sv for population and 4% by Sv for workers, the different being explained by the demography and the sensitivity of the youngest age groups. As regards the low doses of radiations, a bundle of convergent epidemiological observations notices the absence of effects of the low doses rates. Biological mechanisms, notably of repair are approached, then certain accidents (Goiania

  3. Ionizing radiations: effects and sources

    International Nuclear Information System (INIS)

    Vignes, S.; Nenot, J.C.

    1978-01-01

    Having first mentioned the effects of ionizing radiations in cancerogenisis, pre-natal, and genetic fields, the authors present the different sources of radiations and estimate their respective contributions to the total irradiation dose. Their paper makes reference to the main elements of a report issued by the United Nations Scientific Committee in 1977 [fr

  4. Genetic effects of ionising radiation

    International Nuclear Information System (INIS)

    Saunders, P.

    1981-01-01

    The mutagenic effects of ionising radiation on germ cells with resulting genetic abnormalities in subsequent generations, are considered. Having examined a simple model to explain the interaction of ionising radiation with genetic material and discussed its limitations, the methods whereby mutations are transmitted are discussed. Methods of estimating genetic risks and the results of such studies are examined. (U.K.)

  5. Epigenetic effects of ionizing radiation

    International Nuclear Information System (INIS)

    EI-Naggar, A.M.

    2007-01-01

    Data generated during the last three decades provide evidence of Epigenetic Effects that ave-induced by ionizing radiation, particularly those of high LET values, and low level dose exposures. Epigenesist is defined as the stepwise process by which genetic information, as modified by environmental influences, is translated into the substance and behavior of cells, tissues, organism.The epigenetic effects cited in the literature are essentially classified into fine types depending on the type and nature of the effect induced.The most accepted postulation, for the occurrence of these epigenetic effects, is a radiation induced bio electric disturbances in the environment of the non-irradiated cellular volume. This will trigger signals that will induce effects in the unirradiated cells.The epigenetic effects referenced in the literature up to date are five types; namely, Genomic Instability, Bystander. Effects, Clastogenic Plasma Factors,, Abscopal Effects, and Tran generational Effects.The demonstration of Epigenetic Effects associated with exposure to ionizing radiation indicates the need to re- examine the concept of radiation dose and target size. Also an improved understanding of qualifiring and quantifying radiation risk estimates may be attained. Also, a more logical means to understand the underlying mechanisms of radiation induced carcinogenic transformation of cells

  6. Production of narrowband tunable extreme-ultraviolet radiation by noncollinear resonance-enhanced four-wave mixing

    NARCIS (Netherlands)

    Hannemann, S.; Hollenstein, U.; van Duijn, E.J.; Ubachs, W.M.G.

    2005-01-01

    Fourier-transform-limited extreme-ultraviolet (XUV) radiation (bandwidth ≲300 MHz) tunable around 91 nm is produced by use of two-photon resonance-enhanced four-wave mixing on the Kr resonance at 94 093 cm

  7. Radiation hazards and biological effects of ionising radiation on man

    International Nuclear Information System (INIS)

    Siti Najila Mohd Janib

    2004-01-01

    The contents of this chapter are follows - Mechanism of damage: direct action of radiation, indirect action of radiation. Classification of effects: somatic effect, induction of cancer, factors, affecting somatic effects, genetic effect, inherited abnormalities, induced effects, early effects, late effects, deterministic effect, stochastic effect. Effect of specific group: development abnormality, childhood Cancer, fertile women, risk and uncertainty, comparison of risk

  8. Radiation and radiation effects; Strahlung und Strahlenwirkung

    Energy Technology Data Exchange (ETDEWEB)

    Neumaier, S. [Physikalisch-Technische Bundesanstalt, Berlin (Germany). Arbeitsgruppe Strahlenschutz; Janssen, H. [Physikalisch-Technische Bundesanstalt, Berlin (Germany). Abt. Ionisierende Strahlung

    2006-12-15

    The average dose incurred by the German population is about 4 millisievert p.a., about half of which results from natural radiation sources. The second half is caused nearly completely by medical applications. Only a very small fraction of the annual dose results from technical applications. This special issue of PTB focuses on the measuring problems relating to natural radiation sources and technical applications of ionizing radiation. The current contribution also outlines some important aspects of radiation exposure from medical applications. (orig.)

  9. Anomalous response of superconducting titanium nitride resonators to terahertz radiation

    International Nuclear Information System (INIS)

    Bueno, J.; Baselmans, J. J. A; Coumou, P. C. J. J.; Zheng, G.; Visser, P. J. de; Klapwijk, T. M.; Driessen, E. F. C.; Doyle, S.

    2014-01-01

    We present an experimental study of kinetic inductance detectors (KIDs) fabricated of atomic layer deposited TiN films and characterized at radiation frequencies of 350 GHz. The responsivity to radiation is measured and found to increase with the increase in radiation powers, opposite to what is expected from theory and observed for hybrid niobium titanium nitride/aluminium (NbTiN/Al) and all-aluminium (all-Al) KIDs. The noise is found to be independent of the level of the radiation power. The noise equivalent power improves with higher radiation powers, also opposite to what is observed and well understood for hybrid NbTiN/Al and all-Al KIDs. We suggest that an inhomogeneous state of these disordered superconductors should be used to explain these observations

  10. Anomalous response of superconducting titanium nitride resonators to terahertz radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, J., E-mail: j.bueno@sron.nl; Baselmans, J. J. A [SRON, Netherlands Institute of Space Research, Utrecht (Netherlands); Coumou, P. C. J. J.; Zheng, G. [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Visser, P. J. de [SRON, Netherlands Institute of Space Research, Utrecht (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Klapwijk, T. M. [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Physics Department, Moscow State Pedagogical University, 119991 Moscow (Russian Federation); Driessen, E. F. C. [Université Grenoble Alpes, INAC-SPSMS, F-38000 Grenoble (France); CEA, INAC-SPSMS, F-38000 Grenoble (France); Doyle, S. [Cardiff University, School of Physics and Astronomy, Queens Buildings, Cardiff CF24 3AA (United Kingdom)

    2014-11-10

    We present an experimental study of kinetic inductance detectors (KIDs) fabricated of atomic layer deposited TiN films and characterized at radiation frequencies of 350 GHz. The responsivity to radiation is measured and found to increase with the increase in radiation powers, opposite to what is expected from theory and observed for hybrid niobium titanium nitride/aluminium (NbTiN/Al) and all-aluminium (all-Al) KIDs. The noise is found to be independent of the level of the radiation power. The noise equivalent power improves with higher radiation powers, also opposite to what is observed and well understood for hybrid NbTiN/Al and all-Al KIDs. We suggest that an inhomogeneous state of these disordered superconductors should be used to explain these observations.

  11. Resonance-Based Time-Frequency Manifold for Feature Extraction of Ship-Radiated Noise

    Science.gov (United States)

    Yan, Jiaquan; Sun, Haixin; Chen, Hailan; Junejo, Naveed Ur Rehman; Cheng, En

    2018-01-01

    In this paper, a novel time-frequency signature using resonance-based sparse signal decomposition (RSSD), phase space reconstruction (PSR), time-frequency distribution (TFD) and manifold learning is proposed for feature extraction of ship-radiated noise, which is called resonance-based time-frequency manifold (RTFM). This is suitable for analyzing signals with oscillatory, non-stationary and non-linear characteristics in a situation of serious noise pollution. Unlike the traditional methods which are sensitive to noise and just consider one side of oscillatory, non-stationary and non-linear characteristics, the proposed RTFM can provide the intact feature signature of all these characteristics in the form of a time-frequency signature by the following steps: first, RSSD is employed on the raw signal to extract the high-oscillatory component and abandon the low-oscillatory component. Second, PSR is performed on the high-oscillatory component to map the one-dimensional signal to the high-dimensional phase space. Third, TFD is employed to reveal non-stationary information in the phase space. Finally, manifold learning is applied to the TFDs to fetch the intrinsic non-linear manifold. A proportional addition of the top two RTFMs is adopted to produce the improved RTFM signature. All of the case studies are validated on real audio recordings of ship-radiated noise. Case studies of ship-radiated noise on different datasets and various degrees of noise pollution manifest the effectiveness and robustness of the proposed method. PMID:29565288

  12. Current-voltage characteristic of a resonant tunneling diode under electromagnetic radiation

    Directory of Open Access Journals (Sweden)

    N Hatefi Kargan

    2013-09-01

    Full Text Available  In this paper, current-voltage characteristic of a resonant tunneling diode under electromagnetic radiation has been calculated and compared with the results when there is no electromagnetic radiation. For calculating current -voltage characteristic, it is required to calculate the transmission coefficient of electrons from the well and barrier structures of this device. For calculating the transmission coefficient of electrons at the presence of electromagnetic radiation, Finite Difference Time Domain (FDTD method has been used and when there is no electromagnetic radiation Transfer Matrix Method (TMM and finite diffirence time domain method have been used. The results show that the presence of electromagnetic radiation causes resonant states other than principal resonant state (without presence of electromagnetic radiation to appear on the transmition coefficient curve where they are in distances from the principal peak and from each other. Also, the presence of electromagnetic radiation causes peaks other than principal peak to appear on the current-voltage characteristics of the device. Under electromagnetic radiation, the number of peaks on the current-voltage curve is smaller than the number of peaks on the current-voltage transmission coefficient. This is due to the fact that current-voltage curve is the result of integration on the energy of electrons, Thus, the sharper and low height peaks on the transmission coefficient do not appear on the current-voltage characteristic curve.

  13. Radiation effects on structural materials

    International Nuclear Information System (INIS)

    Ghoniem, N.M.

    1991-01-01

    This report discusses the following topics on the effect radiation has on thermonuclear reactor materials: Atomic Displacements; Microstructure Evolution; Materials Engineering, Mechanics, and Design; Research on Low-Activation Steels; and Research Motivated by Grant Support

  14. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Gisone, Pablo; Perez, Maria R.

    2001-01-01

    It has been emphasised the importance of DNA as the main target for ionizing radiation, that can induce damage by its direct action on this molecule or by an indirect effect mediated by free-radicals generated by water radiolysis. Biological effects of ionizing radiation are influenced not only by the dose but also by the dose-rate and the radiation quality. Radiation induced damage, mainly DNA single and double strand breaks, is detected by molecular sensors which in turn trigger signalling cascades leading to cell cycle arrest to allow DNA repair or programmed cell death (apoptosis). Those effects related with cell death, named deterministic, exhibits a dose-threshold below which they are not observed. Acute radiation syndrome and radiological burns are examples of this kind of effects. Other radiation induced effects, called stochastic, are the consequence of cell transformation and do not exhibit a dose-threshold. This is the case of cancer induction and hereditary effects. The aim of this presentation is briefly describe the main aspects of deterministic and stochastic effects from the point of view of radiobiology and radio pathology. (author)

  15. Effects after prenatal radiation exposures

    International Nuclear Information System (INIS)

    Streffer, C.

    2001-01-01

    The mammalian organism is highly radiosensitive during all prenatal developmental periods. For most effects a dose relationship with a threshold is observed. These threshold doses are generally above the exposures from medical diagnostic procedures. The quality and extent of radiation effects are very much dependent on the developmental stage during which an exposure takes place and on the radiation dose. An exposure during the preimplantation period will cause lethality. Malformations are usually induced after exposures during the major organogenesis. Growth retardation is also possible during the late organogenesis and foetal periods. The lower limits of threshold doses for these effects are in the range of 100 mGy. A radiation exposure during the early foetal period can lead to severe mental retardation and impairment of intelligence. There are very serious effects with radiation doses above 0.3 Gy. Carcinogenesis can apparently occur after radiation exposures during the total prenatal development period. The radiation risk factor up to now has not been clear, but it seems that it is in the range of risk factors for cancer that are observed after exposures during childhood. For radiation doses that are used in radiological diagnostics the risk is zero or very low. A termination of pregnancy after doses below 100 mGy should not be considered. (author)

  16. Effects of radiation on erythropoiesis

    Energy Technology Data Exchange (ETDEWEB)

    Harriss, E B

    1971-04-01

    Since the pioneer work of Heineke (1903; 1905) many workers have studied the effect of radiation on haemopoiesis. Their work has been reviewed by Bloom (1948), by Jacobson (1954) and more recently by Bond et al. (1965). The subject continues to stimulate much interest but is now more concerned with the effects of radiation on the multipotential stem cell pool than on radiation damage to the erythropoietic cells themselves. Death from haemopoietic failure following an LD{sub 50/30} dose of radiation is probably not attributable to failure of erythropoiesis; while damage to the erythropoietic system certainly plays a part in the syndrome, it is not a major factor contributing to the death of the animal. Although the severity and time course of the response vary with the species studied, the general effects of radiation on erythropoiesis are similar in all mammalian bone marrow studied to date. Likewise, though the severity of the reaction varies somewhat with the energy of the radiation and has been used to compare the relative biological effectiveness of different types of radiation (Sinclair et al., 1962; Sztanyik, 1967), the response is different only in degree and not in its fundamental pattern. The initial syndrome of depression and recovery will therefore be described largely by reference to work performed on the response of the rat to single acute exposures of either whole-body or partial-body irradiation with conventional X-rays.

  17. Aerosol effects in radiation transfer

    International Nuclear Information System (INIS)

    Binenko, V.I.; Harshvardhan, H.

    1993-01-01

    The radiative properties and effects of aerosols are assessed for the following aerosol sources: relatively clean background aerosol, dust storms and dust outbreaks, anthropogenic pollution, and polluted cloud layers. Studies show it is the submicron aerosol fraction that plays a dominant radiative role in the atmosphere. The radiative effect of the aerosol depends not only on its loading but also on the underlying surface albedo and on solar zenith angle. It is only with highly reflecting surfaces such as Arctic ice that aerosols have a warming effect. Radiometric, microphysical, mineral composition, and refractive index measurements are presented for dust and in particular for the Saharan aerosol layer (SAL). Short-wave radiative heating of the atmosphere is caused by the SAL and is due mainly to absorption. However, the SAL does not contribute significantly to the long-wave thermal radiation budget. Field program studies of the radiative effects of aerosols are described. Anthropogenic aerosols deplete the incoming solar radiation. A case field study for a regional Ukrainian center is discussed. The urban aerosol causes a cooling of metropolitan centers, compared with outlying areas, during the day, which is followed by a warming trend at night. In another study, an increase in turbidity by a factor of 3 due to increased industrialization for Mexico City is noted, together with a drop in atmospheric transmission by 10% over a 50-year period. Numerous studies are cited that demonstrate that anthropogenic aerosols affect both the microphysical and radiative properties of clouds, which in turn affect regional climate. Particles acting as cloud nuclei are considered to have the greatest indirect effect on cloud absorptivity of short-wave radiation. Satellite observations show that low-level stratus clouds contaminated by ship exhaust at sea lead to an increase in cloud albedo

  18. Low level radiation: biological effects

    International Nuclear Information System (INIS)

    Loken, M.K.

    1983-01-01

    It is imperative that physicians and scientists using radiations in health care delivery continue to assess the benefits derived, vs. potential risk, to patients and radiation workers being exposed to radiation in its various forms as part of our health delivery system. Insofar as possible we should assure our patients and ourselves that the benefits outweigh the potential hazards involved. Inferences as to the possible biological effects of low level radiation are generally based on extrapolations from those effects observed and measured following acute exposures to considerably higher doses of radiation. Thus, in order to shed light on the question of the possible biological effects of low level radiation, a wide variety of studies have been carried out using cells in culture and various species of plant and animal life. This manuscript makes reference to some of those studies with indications as to how and why the studies were done and the conclusions that might be drawn there from. In addition reference is made to the handling of this information by scientists, by environmentalists, and by the news media. Unfortunately, in many instances the public has been misled by what has been said and/or written. It is hoped that this presentation will provide an understandable and reasonable perspective on the various appropriate uses of radiation in our lives and how such uses do provide significant improvement in our health and in our quality of life

  19. Effects of water on fingernail electron paramagnetic resonance dosimetry.

    Science.gov (United States)

    Zhang, Tengda; Zhao, Zhixin; Zhang, Haiying; Zhai, Hezheng; Ruan, Shuzhou; Jiao, Ling; Zhang, Wenyi

    2016-09-01

    Electron paramagnetic resonance (EPR) is a promising biodosimetric method, and fingernails are sensitive biomaterials to ionizing radiation. Therefore, kinetic energy released per unit mass (kerma) can be estimated by measuring the level of free radicals within fingernails, using EPR. However, to date this dosimetry has been deficient and insufficiently accurate. In the sampling processes and measurements, water plays a significant role. This paper discusses many effects of water on fingernail EPR dosimetry, including disturbance to EPR measurements and two different effects on the production of free radicals. Water that is unable to contact free radicals can promote the production of free radicals due to indirect ionizing effects. Therefore, varying water content within fingernails can lead to varying growth rates in the free radical concentration after irradiation-these two variables have a linear relationship, with a slope of 1.8143. Thus, EPR dosimetry needs to be adjusted according to the water content of the fingernails of an individual. When the free radicals are exposed to water, the eliminating effect will appear. Therefore, soaking fingernail pieces in water before irradiation, as many researchers have previously done, can cause estimation errors. In addition, nails need to be dehydrated before making accurately quantitative EPR measurements. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  20. Topical Day on Biological Effects of Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Baatout, S.; Jacquet, P.

    1997-05-15

    The topical day has been focussed on the potential effects of ionizing radiation on human health. A general overview on molecular and biophysical aspects of radiation, its effects on cells and organisms, and the contribution of radiobiology to radiation protection and risk assessment is given. The genetic effects of radiation and its effects on the developing organism, the effects of radiation on the cell cycle and the mechanisms of radiation induced apoptosis were also discussed.

  1. Topical Day on Biological Effects of Radiation

    International Nuclear Information System (INIS)

    Baatout, S.; Jacquet, P.

    1997-01-01

    The topical day has been focussed on the potential effects of ionizing radiation on human health. A general overview on molecular and biophysical aspects of radiation, its effects on cells and organisms, and the contribution of radiobiology to radiation protection and risk assessment is given. The genetic effects of radiation and its effects on the developing organism, the effects of radiation on the cell cycle and the mechanisms of radiation induced apoptosis were also discussed

  2. Radiation-induced free radicals in DNA studied by electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Graeslund, A.

    1974-01-01

    Radiation biology aims at an understanding of the effects of radiation on biological material. The studied systems may vary in complexity and size from a whole organism to the molecular constituents of a cell. The observed effects are accordingly varied, from visible somatic effects on the organism to physico-chemical molecular changes. Radiation biophysics may be considered as a specialized branch of radiation biology, dealing with physical aspects of radiation damage, particularly at a molecular or sub-cellular level. The work to be presented here is in the field of radiation biophysics, and concerns physical studies of radiation effects on deoxyribonucleic acid, DNA, the hereditary substance of all living organisms. (author)

  3. Calculation and measurement of radiation corrections for plasmon resonances in nanoparticles

    Science.gov (United States)

    Hung, L.; Lee, S. Y.; McGovern, O.; Rabin, O.; Mayergoyz, I.

    2013-08-01

    The problem of plasmon resonances in metallic nanoparticles can be formulated as an eigenvalue problem under the condition that the wavelengths of the incident radiation are much larger than the particle dimensions. As the nanoparticle size increases, the quasistatic condition is no longer valid. For this reason, the accuracy of the electrostatic approximation may be compromised and appropriate radiation corrections for the calculation of resonance permittivities and resonance wavelengths are needed. In this paper, we present the radiation corrections in the framework of the eigenvalue method for plasmon mode analysis and demonstrate that the computational results accurately match analytical solutions (for nanospheres) and experimental data (for nanorings and nanocubes). We also demonstrate that the optical spectra of silver nanocube suspensions can be fully assigned to dipole-type resonance modes when radiation corrections are introduced. Finally, our method is used to predict the resonance wavelengths for face-to-face silver nanocube dimers on glass substrates. These results may be useful for the indirect measurements of the gaps in the dimers from extinction cross-section observations.

  4. A Novel Murine Model for Localized Radiation Necrosis and its Characterization Using Advanced Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Jost, Sarah C.; Hope, Andrew; Kiehl, Erich; Perry, Arie; Travers, Sarah; Garbow, Joel R.

    2009-01-01

    Purpose: To develop a murine model of radiation necrosis using fractionated, subtotal cranial irradiation; and to investigate the imaging signature of radiation-induced tissue damage using advanced magnetic resonance imaging techniques. Methods and Materials: Twenty-four mice each received 60 Gy of hemispheric (left) irradiation in 10 equal fractions. Magnetic resonance images at 4.7 T were subsequently collected using T1-, T2-, and diffusion sequences at selected time points after irradiation. After imaging, animals were killed and their brains fixed for correlative histologic analysis. Results: Contrast-enhanced T1- and T2-weighted magnetic resonance images at months 2, 3, and 4 showed changes consistent with progressive radiation necrosis. Quantitatively, mean diffusivity was significantly higher (mean = 0.86, 1.13, and 1.24 μm 2 /ms at 2, 3, and 4 months, respectively) in radiated brain, compared with contralateral untreated brain tissue (mean = 0.78, 0.82, and 0.83 μm 2 /ms) (p < 0.0001). Histology reflected changes typically seen in radiation necrosis. Conclusions: This murine model of radiation necrosis will facilitate investigation of imaging biomarkers that distinguish between radiation necrosis and tumor recurrence. In addition, this preclinical study supports clinical data suggesting that diffusion-weighted imaging may be helpful in answering this diagnostic question in clinical settings.

  5. Effects of radiation-counselling convergence education on radiation awareness

    Energy Technology Data Exchange (ETDEWEB)

    Seoung, Youl Hun [Dept. of Radiological Science, College of Health Science, Cheongju University, Cheongju (Korea, Republic of)

    2017-06-15

    The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit.

  6. Effects of radiation-counselling convergence education on radiation awareness

    International Nuclear Information System (INIS)

    Seoung, Youl Hun

    2017-01-01

    The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit

  7. The radiation effects on lipid bilayers

    International Nuclear Information System (INIS)

    Ikigai, Hajime; Matsuura, Tomio; Narita, Noboru; Ozawa, Atsushi.

    1980-01-01

    The Radiation effects on lipid bilayers are studied by the electron spin resonance. Egg lecithin liposomes and human erythrocytes are labeled with spin probes (5 SAL, 12 SAL). Effects of membrane fluidity by X-Ray (or ultraviolet) irradiation are measured by change of the order parameter S. The results obtained are as follows: 1) A similar tendency is observed on the order parameter S between X-Ray irradiated egg lecithin liposomes and human erythrocytes. 2) The rapid changes of the membrane fluidity are observed below 1 krad. The fluctuation of membrane fluidity decreases above 1 krad, consequently the membrane has a tendency changing to a rigid state at low dose area. 3) It is suggested that the more effective radicals are hydroxyl radicals and superoxide radicals. 4) The effects of ultraviolet irradiation with hydrogen peroxide show that hydroxyl radicals lead to changes of membrane fluidity. (author)

  8. Tunable soliton-induced resonant radiation by three-wave mixing

    DEFF Research Database (Denmark)

    Zhou, B. B.; Liu, X.; Guo, H. R.

    2017-01-01

    A remarkable feature about the temporal optical soliton is that it can be phase-matched to new frequencies, emitting so-called resonant radiation (RR). This constitutes an efficient source of ultrafast pulses in emerging wavelength regimes, and plays a vital role in coherently extending the super......A remarkable feature about the temporal optical soliton is that it can be phase-matched to new frequencies, emitting so-called resonant radiation (RR). This constitutes an efficient source of ultrafast pulses in emerging wavelength regimes, and plays a vital role in coherently extending...

  9. Nonlinear narrow Doppler-free resonances for optical transitions and annihilation radiation of a positronium atom

    International Nuclear Information System (INIS)

    Letokhov, V.S.; Minogin, V.G.

    1976-01-01

    The possibilities of obtaining narrow resonances without the Doppler broadening for transition between the fine structure levels of the ground and first excited states of a positronium atom are considered. An analysis is carried out of the conditions required for observation of the narrow resonances of saturation of single quantum absorption in the 1S-2P transitions and observation of narrow two-photon absorption resonances in the 1S-2S transitions. It is shown that narrow 2γ annihilation radiation lines of a positronium atom may be obtained with a width much smaller than the Doppler one

  10. Electron scattering by an atom in the field of resonant laser radiation

    International Nuclear Information System (INIS)

    Agre, M.; Rapoport, L.

    1982-01-01

    The collision of an electron with an atom in the field of intense electromagnetic radiation that is at resonance with two atomic multiplets is investigated theoretically. Expressions are obtained for the amplitudes of the elastic and inelastic scattering with emission (absorption) of photons. The case of a ground state at resonance with a doublet is considered in detail. It is shown that photon absorption takes place predominantly in the case of resonance in inelastic transitions from a state of the lower multiplet, and photon emission takes place in transitions from a state of the upper multiplet

  11. Radiation, chemicals and combined effects

    International Nuclear Information System (INIS)

    Sinclair, W.K.

    1991-01-01

    A brief background has been provided on current carcinogenic risks from ionizing radiation and their magnitude in background circumstances. The magnitude of the risks from possibly carcinogenic chemicals at background levels in air, water and food are surprisingly similar. The exception is, perhaps, for the single source of radon which, while variable, on the average stands out above all other sources. Some basic principles concerning the interaction of combined radiation and chemicals and some practical examples where the two interact synergistically to enhance radiation effects has also been provided. Areas for human research in the future are discussed. (Author)

  12. Measuring space radiation shielding effectiveness

    OpenAIRE

    Bahadori Amir; Semones Edward; Ewert Michael; Broyan James; Walker Steven

    2017-01-01

    Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles ...

  13. Radiation effects in optical components

    International Nuclear Information System (INIS)

    Friebele, E.J.

    1987-01-01

    This report discusses components of high performance optical devices may be exposed to high energy radiation environments during their lifetime. The effect of these adverse environments depends upon a large number of parameters associated with the radiation (nature, energy, dose, dose rate, etc.) or the system (temperature, optical performance requirements, optical wavelength, optical power, path length, etc.), as well as the intrinsic susceptibility of the optical component itself to degradation

  14. Environmental dosimetry and radiation effects

    International Nuclear Information System (INIS)

    Woodhead, D.S.

    1997-01-01

    Specific assessment of the potential effects on wild organisms of increased radiation exposure arising from the authorized disposal of radioactive wastes to the environment requires two interrelated sets of information. First, an estimate is required of the incremental radiation exposure; and second, dose rate-response relationships are necessary to predict the potential impact of the estimated incremental exposure. Each of these aspects will be discussed in detail. (author)

  15. Radiation effects at the SSC

    Energy Technology Data Exchange (ETDEWEB)

    Gilchriese, M.G.D. [ed.] [Superconducting Super Collider Lab., Dallas, TX (United States)

    1988-06-01

    This report contains a preliminary study of the effects of the radiation levels expected at the SSC on potential detector components and a subset of materials to be used in the SSC accelerators. The report does not contain a discussion of radiation damage to electronics components that may be used at the SSC. We have investigated many of the effects of radiation on silicon detectors, on wire chambers, on scintillating materials and the associated readout, on optical fibers for data transmission and on structural or other materials to be used in detector or accelerator components. In the SSC accelerator complex, in particular the storage rings, radiation damage will not present significant problems different than those now faced by existing high energy accelerators. We find that the effects of radiation damage on SSC detector components will be significant at the design luminosity of the ssc and will limit, or determine, many of the options for different detector components. In this regard the reader should keep in mind that, in the absence of a specific detector design, it is not possible to form definitive conclusions regarding the viability of the detector components. Since the radiation levels in experiments at the SSC will depend on the geometry and composition of the apparatus, simple yes /no generalizations about the feasibility of a detector component are not possible.

  16. Electron Paramagnetic Resonance pO2 Image Tumor Oxygen-Guided Radiation Therapy Optimization.

    Science.gov (United States)

    Epel, Boris; Maggio, Matt; Pelizzari, Charles; Halpern, Howard J

    2017-01-01

    Modern standards for radiation treatment do not take into account tumor oxygenation for radiation treatment planning. Strong correlation between tumor oxygenation and radiation treatment success suggests that oxygen-guided radiation therapy (OGRT) may be a promising enhancement of cancer radiation treatment. We have developed an OGRT protocol for rodents. Electron paramagnetic resonance (EPR) imaging is used for recording oxygen maps with high spatial resolution and excellent accuracy better than 1 torr. Radiation is delivered with an animal intensity modulated radiation therapy (IMRT) XRAD225Cx micro-CT/ therapy system. The radiation plan is delivered in two steps. First, a uniform 15% tumor control dose (TCD 15 ) is delivered to the whole tumor. In the second step, an additional booster dose amounting to the difference between TCD 98 and TCD 15 is delivered to radio-resistant, hypoxic tumor regions. Delivery of the booster dose is performed using a multiport conformal beam protocol. For radiation beam shaping we used individual radiation blocks 3D-printed from tungsten infused ABS polymer. Calculation of beam geometry and the production of blocks is performed next to the EPR imager, immediately after oxygen imaging. Preliminary results demonstrate the sub-millimeter precision of the radiation delivery and high dose accuracy. The efficacy of the radiation treatment is currently being tested on syngeneic FSa fibrosarcoma tumors grown in the legs of C3H mice.

  17. Electron paramagnetic resonance study on the ionizing radiation induced defects of the tooth enamel hydroxyapatite

    International Nuclear Information System (INIS)

    Oliveira, Liana Macedo de

    1995-01-01

    Hydroxyapatite is the main constituent of calcified tissues. Defects induced by ionizing radiations in this biomineral can present high stability and then, these are used as biological markers in radiological accidents, irradiated food identifying and geological and archaeological dating. In this work, paramagnetic centers induced on the enamel of the teeth by environmental ionizing radiation, are investigated by electron paramagnetic resonance (EPR). Decay thermal kinetic presents high complexity and shows the formation of different electron ligation energy centers and structures

  18. Susceptibility effects in nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ziener, Christian Herbert

    2008-01-01

    The properties of dephasing and the resulting relaxation of the magnetization are the basic principle on which all magnetic resonance imaging methods are based. The signal obtained from the gyrating spins is essentially determined by the properties of the considered tissue. Especially the susceptibility differences caused by magnetized materials (for example, deoxygenated blood, BOLD-effect) or magnetic nanoparticles are becoming more important for biomedical imaging. In the present work, the influence of such field inhomogeneities on the NMR-signal is analyzed. (orig.)

  19. Nuclear resonance scattering of synchrotron radiation as a unique electronic, structural and thermodynamic probe

    International Nuclear Information System (INIS)

    Alp, E. Ercan; Sturhahn, Wolfgang; Toellner, Thomas S.; Zhao, Jiyong; Leu, Bogdan M.

    2012-01-01

    Discovery of Moessbauer effect in a nuclear transition was a remarkable development. It revealed how long-lived nuclear states with relatively low energies in the kiloelectron volt (keV) region can be excited without recoil. This new effect had a unique feature involving a coupling between nuclear physics and solid-state physics, both in terms of physics and sociology. Physics coupling originates from the fact that recoilless emission and absorption or resonance is only possible if the requirement that nuclei have to be bound in a lattice with quantized vibrational states is fulfilled, and that the finite electron density on the nucleus couples to nuclear degrees of freedom leading to hyperfine interactions. thus, Moessbauer spectroscopy allows peering into solid-state effects using unique nuclear transitions. Sociological aspects of this coupling had been equally startling and fruitful. The interaction between diverse scientific communities, who learned to use Moessbauer spectroscopy proved to be very valuable. For example, biologists, geologists, chemists, physics, materials scientists, and archeologists, all sharing a common spectroscopic technique, also learned to appreciate the beauty and intricacies of each other's fields. As a laboratory-based technique, Moessbauer spectroscopy matured by the end of the 1970s. Further exciting developments took place when accelerator-based techniques were employed, like synchrotron radiation or 'in-beam'Moessbauer experiments with implanted radioactive ions. More recently, two Moessbauer spectrometers on the surface of the Mars kept the technique vibrant and viable up until present time. In this chapter, the authors look into some of the unique aspects of nuclear resonance excited with synchrotron radiation as a probe of condensed matter, including magnetism, valence, vibrations, and lattice dynamics, and review the development of nuclear resonance inelastic x-ray scattering (NRIXS) and synchrotron Moessbauer spectroscopy

  20. Photon strength functions in Gd isotopes studied from radiative capture of resonance neutrons

    Directory of Open Access Journals (Sweden)

    Kroll J.

    2014-04-01

    Full Text Available The experimental spectra of γ rays following radiative neutron capture on isolated resonances of stable 152,154–158Gd targets were measured by the DANCE calorimeter installed at the Los Alamos Neutron Scattering Center in New Mexico, USA. These spectra were analyzed within the extreme statistical model to get new information on the photon strength functions. Special emphasis was put on study of the scissors vibrational mode present in these isotopes. Our data show that the scissors-mode resonances are built not only on the ground states but also on the excited levels of all studied Gd isotopes. The scissors mode strength observed in 157,159Gd products is significantly higher than in neighboring even-even nuclei 156,158Gd. Such a difference indicates the existence of an odd-even effect in the scissors mode strength. Moreover, there exists no universal parameter-free model of the electric dipole photon strength function describing the experimental data in all of the Gd isotopes studied. The results for the scissors mode are compared with the (γ, γ′ data for the ground-state transitions and with the results from 3He-induced reactions.

  1. Health effects of ionising radiation

    International Nuclear Information System (INIS)

    Mohammadi, S.

    2000-01-01

    Human and animal studies have shown an increased incidence of cancer and malformation due to radioactive materials and external radiation. The biological effects of radiation on tissues are the occurrence of morphological and functional changes in the body. The critical parts of the body are those tissues or organs which when irradiated, are likely to influence the health of the individual or its offspring. The probability of these changes depends on the radiation dose. There are two main types of damage due to radiation dose. Radiation Sickness with well-defined symptoms like cancer and inherited disorders which can appear after several years. A second type of damage, namely Acute Radiation Sickness results after exposure of the whole or parts of the body to high doses of radiation greater than 1 Gy. There are safety standards for the amount of dose equivalent that is taken as acceptable. The International Commission on Radiological Protection (ICRP) has given norms in which natural and medical causes were not included. These are given as recommended values (1966) and proposed values (2000), both in mSv/yr: population at large: 1.7 and 0.4; members of the public: 5 and 2; and radiologic workers: 50 and 20, respectively. Taking into account the increased number of reactor accidents, the question is how safe is our safety standards? Even when one is able to connect a quantitative risk with a radiation dose, there are three fundamental principles which we should obey in dealing with risks from radiation. These are: (1) Avoid any risk. (2) The risk should be related to the possible benefit. (3) Any dose below the politically agreed limits is acceptable

  2. Harmful effects of ultraviolet radiation

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Tanning for cosmetic purposes by sunbathing or by using artificial tanning devices is widespread. The hazards associated with exposure to ultraviolet radiation are of concern to the medical profession. Depending on the amount and form of the radiation, as well as on the skin type of the individual exposed, ultraviolet radiation causes erythema, sunburn, photodamage (photoaging), photocarcinogenesis, damage to the eyes, alteration of the immune system of the skin, and chemical hypersensitivity. Skin cancers most commonly produced by ultraviolet radiation are basal and squamous cell carcinomas. There also is much circumstantial evidence that the increase in the incidence of cutaneous malignant melanoma during the past half century is related to increased sun exposure, but this has not been proved. Effective and cosmetically acceptable sunscreen preparations have been developed that can do much to prevent or reduce most harmful effects to ultraviolet radiation if they are applied properly and consistently. Other safety measures include (1) minimizing exposure to ultraviolet radiation, (2) being aware of reflective surfaces while in the sun, (3) wearing protective clothing, (4) avoiding use of artificial tanning devices, and (5) protecting infants and children

  3. Biological effects of nuclear radiation

    International Nuclear Information System (INIS)

    Hotz, G.

    1975-01-01

    After a brief survey about the main radiobiological effects caused by ionizing radiation, human symptoms after irradiation and incorporation are shown. The special radiotoxic effect of radionuclides which are chemically associated with metabolism-specific elements such as calcium and potassium is shown and methods of treatment are indicated. (ORU) [de

  4. Radiation Effects in Carbon Nanoelectronics

    Directory of Open Access Journals (Sweden)

    Cory D. Cress

    2012-07-01

    Full Text Available We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

  5. Magnetodielectric effect of Mn–Zn ferrite at resonant frequency

    International Nuclear Information System (INIS)

    Pengfei, Pan; Ning, Zhang

    2016-01-01

    The dielectric properties and the magnetodielectric effect in Mn–Zn ferrite at resonant frequency have been studied in this paper. Dimensional-resonance-induced abnormal dielectric spectrum was observed at f≈1 MHz. The relatively large magnetodielectric ratio of 4500% in a magnetic field of 3.5 kOe was achieved from the Mn–Zn ferrite sample with the initial permeability of 15 K at resonant frequency at room temperature. Theoretical analysis suggests that the large MD effect at resonant frequency is attributed to the enhanced magnetostriction effect. - Highlights: • Dimensional resonance was measured in dielectric spectrum at f≈1 MHz. • The MD ratio of 4500% was induced by H = 3.5 kOe at resonant frequency. • The magnetostriction effect leads to the large MD effect at resonant frequency.

  6. Nuclear resonant scattering of synchrotron radiation from nuclei in the Brownian motion

    International Nuclear Information System (INIS)

    Razdan, Ashok

    2003-01-01

    The time evolution of the coherent forward scattering of the synchrotron radiation for resonant nuclei in Brownian motion is studied. Apart from target thickness, the appearance of the dynamical beats also depends on 'α' which is the ratio of the harmonic force constant to the damping force constant of harmonic oscillator undergoing Brownian motion

  7. Experimental study of intense radiation in terahertz region based on cylindrical surface wave resonator

    International Nuclear Information System (INIS)

    Gong, Shaoyan; Ogura, Kazuo; Yambe, Kiyoyuki; Nomizu, Shintaro; Shirai, Akihiro; Yamazaki, Kosuke; Kawamura, Jun; Miura, Takuro; Takanashi, Sho; San, Min Thu

    2015-01-01

    Periodical corrugations structured on a cylindrical conductor have cylindrical surface waves (CSWs), which are reflected at the corrugation ends and form a CSW-resonator. In this paper, intense radiations in terahertz region based on the CSW-resonator are reported. The CSW-resonators with upper cut off frequencies in the modern IEEE G-band (110–300 GHz) are excited by a coaxially injected annular beam in a weakly relativistic region less than 100 kV. It is shown that there exists an oscillation starting energy for the CSW-resonator. Above the starting energy, very intense terahertz radiations on the order of kW are obtained. The operation frequencies in the range of 166–173 GHz and 182–200 GHz are obtained using two types of CSW-resonator with the different corrugation amplitude. Electromagnetic properties of the CSW-resonator can be controlled by the artificial structure and may play an important role in high-intensity terahertz generations and applications

  8. The isovector quadrupole resonance in yttrium excited by neutron radiative capture

    International Nuclear Information System (INIS)

    Zorro, R.; Bergqvist, I.

    1987-01-01

    In order to investigate the properties of the isovector giant quadrupole resonance (ΔT=1, ΔS=0) in the A=90 mass region, gamma-ray spectra from the reaction 89 Y(n,γ) 90 Y were recorded at several neutron energies in the energy range 12 to 27 MeV at 55 0 , 90 0 and 125 0 . The measured fore-aft asymmetry for the ground-state transition is very small in the low-energy region, but becomes appreciable above a neutron energy of 18 MeV. The observed asymmetry is attributed to interference between radiation from the isovector giant quadrupole resonance and radiation of opposite parity (from the high-energy tail of the giant dipole resonance and direct E1 capture). The data obtained in the present work, interpreted in terms of the direct-semidirect capture model, indicate that the excitation energy of the isovector E2 resonance in 90 Y is 26 ± 1 MeV. The data are consistent with a resonance width of 10 ± 2 MeV and with complete exhaustion of the energy-weighted sum rule for the lower isospin component of the resonance. (orig.)

  9. Kinetic theory of radiation effects

    International Nuclear Information System (INIS)

    Mansur, L.K.

    1987-01-01

    To help achieve the quantitative and mechanistic understanding of these processes, the kinetic theory of radiation effects has been developed in the DOE basic energy sciences radiation effects and fusion reactor materials programs, as well as in corresponding efforts in other countries. This discipline grapples with a very wide range of phenomena and draws on numerous sub-fields of theory such as defect physics, diffusion, elasticity, chemical reaction rates, phase transformations and thermodynamics. The theory is cast in a mathematical framework of continuum dynamics. Issues particularly relevant to the present inquiry can be viewed from the standpoints of applications of the theory and areas requiring further progress

  10. Geometrical resonance effects in thin superconducting films

    International Nuclear Information System (INIS)

    Nedellec, P.

    1977-01-01

    Electron tunneling density of states measurements on thick and clear superconducting films (S 1 ) backed by films in the normal or superconducting state (S 2 ) show geometrical resonance effects associated with the spatial variation of Δ(x), the pair potential, near the interface S 1 -S 2 . The present understanding of this so-called 'Tomasch effect' is described. The dispersion relation and the nature of excitations in the superconducting state are introduced. It is shown that the introduction of Green functions give a general description of the superconducting state. The notion of Andreev scattering at the S 1 -S 2 interface is presented and connect the geometrical resonance effects to interference process between excitations. The different physical parameters involved are defined and used in the discussion of some experimental results: the variation of the period in energy with the superconducting thickness is connected to the renormalized group velocity of excitations traveling perpendicular to the film. The role of the barrier potential at the interface on the Tomasch effect is described. The main results discussed are: the decrease of the amplitude of the Tomasch structures with energy is due to the loss of the mixed electron-hole character of the superconducting excitations far away from the Fermi level; the variation of the pair potential at the interface is directly related to the amplitude of the oscillations; the tunneling selectivity is an important parameter as the amplitude as well as the phase of the oscillations are modified depending on the value of the selectivity; the phase of the Tomasch oscillations is different for an abrupt change of Δ at the interface and for a smooth variation. An ambiguity arises due to the interplay between these parameters. Finally, some experiments, which illustrate clearly the predicted effects are described [fr

  11. Reflection effect of localized absorptive potential on non-resonant and resonant tunneling

    International Nuclear Information System (INIS)

    Rubio, A.; Kumar, N.

    1992-06-01

    The reflection due to absorptive potential (-iV i ) for resonant and non-resonant tunneling has been considered. We show that the effect of reflection leads to a non-monotonic dependence of absorption on the strength V i with a maximum absorption of typically 0.5. This has implications for the operation of resonant tunneling devices. General conceptual aspects of absorptive potentials are discussed. (author). 9 refs, 2 figs

  12. Interference scattering effects on intermediate resonance absorption at operating temperatures

    International Nuclear Information System (INIS)

    Goldstein, R.

    1975-01-01

    Resonance integrals may be accurately calculated using the intermediate resonance (IR) approximation. Results are summarized for the case of an absorber with given potential scattering cross sections and interference scattering parameter admixed with a non absorbing moderator of given cross section and located in a narrow resonance moderating medium. From the form of the IR solutions, it is possible to make some general observations about effects of interference scattering on resonance absorption. 2 figures

  13. Nonlinear real index of refraction variations of a gas medium due to a monochromatic radiation near resonance

    International Nuclear Information System (INIS)

    Vasconcellos, J.I.C.

    1982-01-01

    The nonlinear real index of refraction variations of a gas medium due to a strong monochromatic radiation causing saturation effects is calculated. The gas is supposed to be composed of two-level molecules with which the external field is nearly resonant. It is assumed homogeneous (hard collisions, spontaneous decay) and inhomogeneous (Doppler effect) broadening mechanisms acting on the real index of refraction of the medium. The nonlinear dispersion of the medium is studied as a function of the detuning frequencies, saturation conditions and for various ratios between the homogeneous and inhomogeneous linewidths. In particular, the modification of the index of refraction due to saturation effects are emphasized. (Author) [pt

  14. Homogenized boundary conditions and resonance effects in Faraday cages

    Science.gov (United States)

    Hewett, D. P.; Hewitt, I. J.

    2016-05-01

    We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called `Faraday cage effect'). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells.

  15. Radiation research contracts: Biological effects of small radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Hug, O [International Atomic Energy Agency, Division of Health, Safety and Waste Disposal, Vienna (Austria)

    1959-04-15

    To establish the maximum permissible radiation doses for occupational and other kinds of radiation exposure, it is necessary to know those biological effects which can be produced by very small radiation doses. This particular field of radiation biology has not yet been sufficiently explored. This holds true for possible delayed damage after occupational radiation exposure over a period of many years as well as for acute reactions of the organism to single low level exposures. We know that irradiation of less than 25 Roentgen units (r) is unlikely to produce symptoms of radiation sickness. We have, however, found indications that even smaller doses may produce certain instantaneous reactions which must not be neglected

  16. Photon cooperative effect in resonance spectroscopy

    International Nuclear Information System (INIS)

    Veklenko, B.A.

    1998-01-01

    A systematic method is proposed for calculating the density matrix of subsystems interacting with their environment under conditions of thermodynamic equilibrium. The density matrix of photons resonantly interacting with a surrounding gas is calculated. It is shown that use of the Gibbs distribution allows one to completely eliminate inelastic processes from the calculations. A correct account of photon-photon correlators indicates the presence of new cooperative effects. A new branch of the polariton spectrum is predicted, which is due to the presence of excited atoms in the medium. With the help of the density matrix the mean filling numbers of the photon modes are calculated. In terms of wavelengths, we have obtained a generalization of the Planck formula which accounts for photon cooperative phenomena. The manifestation of these effects in kinetic processes is discussed

  17. Resonance effects in neutron scattering lengths

    Energy Technology Data Exchange (ETDEWEB)

    Lynn, J.E.

    1989-06-01

    The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-/angstrom/ wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs.

  18. Resonance effects in neutron scattering lengths

    International Nuclear Information System (INIS)

    Lynn, J.E.

    1989-01-01

    The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-angstrom wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs

  19. The effects and control of radiation

    International Nuclear Information System (INIS)

    Saunders, P.A.H.

    1982-12-01

    The subject is discussed under the headings: introduction; ionising radiation (alpha and beta particles, gamma- and X-radiation, neutrons, half-life, sources of radiation); biological effects; risk estimates (somatic) (early effects, delayed effects); risk estimates (hereditary); control of radiation; risk estimates (accidents). (U.K.)

  20. Health effects of ionizing radiation

    International Nuclear Information System (INIS)

    Radford, E.P.

    1980-01-01

    This presentation is restricted to the health effects of low doses of ionizing radiation. In general, these cumulative exposures are well below 100 rem, or about 50 times background or less. The two effects of interest in this dose range are genetic mutations and cancer production. The genetic effects will not be discussed in detail. The chief reason for the rise in risk estimates for cancer is the longer follow-up of exposed populations

  1. Investigation of resonant polarization radiation of relativistic electrons in gratings at small angles

    International Nuclear Information System (INIS)

    Aleinik, A.N.; Chefonov, O.V.; Kalinin, B.N.; Naumenko, G.A.; Potylitsyn, A.P.; Saruev, G.A.; Sharafutdinov, A.F.

    2003-01-01

    The resonant optical polarization radiation (ROPR) in the Smith-Purcell geometry and the one from the inclined grating at the Tomsk synchrotron and 6-MeV microtron have been investigated. The polarization radiation was observed at 4.2 deg. from the 200 MeV electron beam and at 5 deg. from the 6.2 MeV electron beam. Two methods of measurement of ROPR maxima in these two cases have been used. In the first case (the experiment on synchrotron) we have fixed the wavelength of radiation using an optical filter; the orientation dependence of this radiation was measured. In this dependence we have observed two peaks of radiation from electrons in gold foil grating of 0.1 mm period. The first large peak is a zeroth order peak in direction of specular reflection, and the second one is the first-order peak of resonant polarization radiation. In the experiment on microtron the spectra of ROPR from aluminum foil strip grating of 0.2 mm period in the Smith-Purcell geometry were measured, and the peak of the first-order Smith-Purcell radiation in these spectra was observed. The comparison of data obtained with the simulation results has been performed

  2. Effect of resonance line shape on precision measurements of nuclear magnetic resonance shifts

    International Nuclear Information System (INIS)

    Kachurin, A.M.; Smelyanskij, A.Ya.

    1986-01-01

    Effect of resonance line shape on the systematic error of precision measurements of nuclear magnetic resonance (NMR) shifts of high resolution (on the center of NMR dispersion line) is analysed. Effect of the device resonance line form-function asymmetry is evaluated; the form-function is determined by configuration of the spectrometer magnetic field and enters the convolution, which describes the resonance line form. It is shown that with the increase of the relaxation line width the form-function effect on the measurement error yields to zero. The form-function effect on measurements and correction of a phase angle of NMR detection is evaluated. The method of semiquantitative evaluation of resonance line and NMR spectrometer parameters, guaranteeing the systematic error of the given infinitesimal, is presented

  3. Radiation-induced electron paramagnetic resonance signal and soybean isoflavones content

    International Nuclear Information System (INIS)

    Oliveira, Marcos R.R. de; Mandarino, José M.G.; Mastro, Nelida L. del

    2012-01-01

    Electron Paramagnetic Resonance (EPR) is a well-known spectroscopic technique that detects paramagnetic centers and can detect free radicals with high sensitivity. In food, free radicals can be generated by several commonly used industrial processes, such as radiosterilization or heat treatment. EPR spectroscopy is used to detect radioinduced free radicals in food. In this work the relation between EPR signal induced by gamma irradiation treatment and soybean isoflavones content was investigated. Present results did not show correlation between total isoflavones content and the EPR signal. Nevertheless, some isoflavone contents had a negative correlation with the radiation-induced EPR signal. - Highlights: ► Electron Paramagnetic Resonance (EPR) detects free radicals. ► Ionizing radiation as free radicals inducer. ► Total soybean isoflvones do not correlate with radiation-induced EPR intensity but a soybean glucosyl glucoside isoflavone does.

  4. Ultrasound appearance of radiation-induced hepatic injury. Correlation with computed tomography and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Garra, B.S.; Shawker, T.H.; Chang, R.; Kaplan, K.; White, R.D.

    1988-01-01

    The ultrasound findings in three cases of radiation-induced hepatic injury are described and compared with computed tomography and magnetic resonance imaging findings. Fatty infiltration of the liver was present in two of the cases in which concurrent chemotherapy was being administered. On ultrasound B-scans, the regions of radiation injury were hypoechoic relative to the remainder of the liver. This finding was more obvious in the patients with fatty livers. CT scans on the patients with fatty infiltrated livers showed higher attenuation in the irradiated region than in unexposed liver. In the patient where no fatty infiltration was present, the radiated section of liver had lower attenuation consistent with previous reports. Magnetic resonance imaging showed decreased signal in the exposed areas on T1 weighted images

  5. Measured pulse width of sonoluminescence flashes in the form of resonance radiation

    Science.gov (United States)

    Giri, Asis; Arakeri, Vijay H.

    1998-09-01

    Recent studies have shown that the measured flash widths from single and multibubble sonoluminescence are in subnanosecond or even picosecond regime. Here, we provide conclusive evidence for the existence of nanosecond multibubble sonoluminescence. This has become possible by our ability to find a medium from which exclusive sodium D line resonance radiation as a form of sonoluminescence is possible. The measured flash width of this emission is found to be in the range of tens of nanoseconds and is sensitively dependent on experimental parameters. Our finding is important since all the earlier pulse width measurements have been limited to emission with the physical source or species responsible for observed optical radiation not being clearly identified. We propose that the presently observed resonance radiation is from ``soft'' bubble collapse as analyzed by V. Kamath et al. [J. Acoust. Soc. Am. 94, 248 (1993)].

  6. Stimulating effects of ionizing radiation

    International Nuclear Information System (INIS)

    Jaworowski, Z.

    1995-01-01

    The influence of low doses on human organism is not definite known up to now. The worldwide discussion on this topic has been presented. A lot of analysed statistical data proved that the stimulating effect of low doses of ionizing radiation really exists and can have a beneficial influence on human health. 43 refs, 4 figs, 6 tabs

  7. Radiation effects on video imagers

    International Nuclear Information System (INIS)

    Yates, G.J.; Bujnosek, J.J.; Jaramillo, S.A.; Walton, R.B.; Martinez, T.M.; Black, J.P.

    1985-01-01

    Radiation sensitivity of several photoconductive, photoemissive, and solid state silicon-based video imagers was measured by analyzing stored photocharge induced by irradiation with continuous and pulsed sources of high energy photons and neutrons. Transient effects as functions of absorbed dose, dose rate, fluences, and ionizing particle energy are presented

  8. Biopositive Effects of Ionizing Radiation?

    International Nuclear Information System (INIS)

    Broda, E.

    1972-01-01

    This paper was written for a talk given by E. Broda in Vienna for an event organised by the chemical physical society, the Austrian biochemical society and the Austrian biophysical society in December 1972. In this paper Broda analyses the question of biopositive effects of ionizing radiation. (nowak)

  9. Modification of radiation effects

    International Nuclear Information System (INIS)

    Lindenbaum, A.

    1975-01-01

    Results are reported from studies on the tissue distribution of 239 Pu and 241 Am in mice and beagle dogs and the effectiveness of various therapeutic treatments for decorporation. In dogs injected with monomeric Pu the value of a regimen of early and prolonged treatment with DTPA (diethylenetriaminepentaacetic acid) for minimizing the Pu burden in the soft tissues and skeleton was demonstrated. These results have immediate implication for DTPA treatment in man. New studies in mice verified the action of pyran copolymer antiviral agents in enhancing the effectiveness of DTPA for removal of polymeric Pu from the liver. Recent application of autoradiographic procedures for quantitatively comparing short- and long-term localization of monomeric and polymeric 239 Pu in dog liver showed that there is no net translocation of monomeric Pu within the liver between 6 and 90 days following injection. One of the molecular studies presently underway aims at synthesis of a variety of DTPA esters. The diethyl ester has already been prepared and tested for toxicity in mice. These compounds are designed to bring DTPA into contact with plutonium deposits unavailable to the action of ionic DTPA. (U.S.)

  10. Radiation effects on eye components

    Science.gov (United States)

    Durchschlag, H.; Fochler, C.; Abraham, K.; Kulawik, B.

    1999-08-01

    The most important water-soluble components of the vertebrate eye (lens proteins, aqueous humor, vitreous, hyaluronic acid, ascorbic acid) have been investigated in aqueous solution, after preceding X- or UV-irradiation. Spectroscopic, chromatographic, electrophoretic, hydrodynamic and analytic techniques have been applied, to monitor several radiation damages such as destruction of aromatic and sulfur-containing amino acids, aggregation, crosslinking, dissociation, fragmentation, and partial unfolding. Various substances were found which were able to protect eye components effectively against radiation, some of them being also of medical relevance.

  11. Homogenized boundary conditions and resonance effects in Faraday cages

    Science.gov (United States)

    Hewitt, I. J.

    2016-01-01

    We present a mathematical study of two-dimensional electrostatic and electromagnetic shielding by a cage of conducting wires (the so-called ‘Faraday cage effect’). Taking the limit as the number of wires in the cage tends to infinity, we use the asymptotic method of multiple scales to derive continuum models for the shielding, involving homogenized boundary conditions on an effective cage boundary. We show how the resulting models depend on key cage parameters such as the size and shape of the wires, and, in the electromagnetic case, on the frequency and polarization of the incident field. In the electromagnetic case, there are resonance effects, whereby at frequencies close to the natural frequencies of the equivalent solid shell, the presence of the cage actually amplifies the incident field, rather than shielding it. By appropriately modifying the continuum model, we calculate the modified resonant frequencies, and their associated peak amplitudes. We discuss applications to radiation containment in microwave ovens and acoustic scattering by perforated shells. PMID:27279775

  12. Bioceramic Resonance Effect on Meridian Channels: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Ting-Kai Leung

    2015-01-01

    Full Text Available Bioceramic is a kind of material which emits nonionizing radiation and luminescence, induced by visible light. Bioceramic also facilitates the breakup of large clusters of water molecules by weakening hydrogen bonds. Hydrogen bond weakening, which allows water molecules to act in diverse ways under different conditions, is one of the key mechanisms underlying the effects of Bioceramic on biophysical and physical-chemical processes. Herein, we used sound to amplify the effect of Bioceramic and further developed an experimental device for use in humans. Thirteen patients who suffered from various chronic and acute illnesses that severely affected their sleep patterns and life quality were enrolled in a trial of Bioceramic resonance (i.e., rhythmic 100-dB sound waves with frequency set at 10 Hz applied to the skin surface of the anterior chest. According to preliminary data, a “Propagated Sensation along Meridians” (PSM was experienced in all Bioceramic resonance-treated patients but not in any of the nine control patients. The device was believed to enhance microcirculation through a series of biomolecular and physiological processes and to subject the specific meridian channels of Traditional Chinese Medicine (TCM to coherent vibration. This noninvasive technique may offer an alternative to needle acupuncture and other traditional medical practices with clinical benefits.

  13. Radiation Effects in Paediatric radiography

    International Nuclear Information System (INIS)

    Mutwasi, O.

    2006-01-01

    Diagnostic imaging has evolved from single technique to a field which we have a choice from many modalities. Some without radiation. Radiation producing modalities include plain films (low dose), Fluoroscopy (mid range dose), Computed tomography (high dose). Radiography dose can significantly be influenced in plain radiography by varying speed of screens, cassette construction and type of radiography. E.g. digital or computed. In computed or digital radiography we are no longer able to tell h igh dose b y the quality of images. The final image is by great extend a product of post processing algorithms. It's for this reasons that the basic understanding of the sensitivity and specifying of various types of examinations and of specifically radiation effects is mandatory for a paediatric imager

  14. Measuring space radiation shielding effectiveness

    Directory of Open Access Journals (Sweden)

    Bahadori Amir

    2017-01-01

    Full Text Available Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

  15. Measuring space radiation shielding effectiveness

    Science.gov (United States)

    Bahadori, Amir; Semones, Edward; Ewert, Michael; Broyan, James; Walker, Steven

    2017-09-01

    Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

  16. Biological radiation effects

    International Nuclear Information System (INIS)

    Russo, A.

    2000-01-01

    Everyone is exposed to a complex mix of electromagnetic fields (EMF) of different frequencies that permeate our environment. Exposures to these EMF are increasing significantly as technology advances unabated and new applications are found. Technological progress in the broadest sense of the word has always been associated with various hazards and risks, both perceived and real. The industrial, commercial and household application on EMF is no exception. Throughout the world, the general public is concerned that exposure to EMF from such sources as high voltage power lines, broadcasting networks, mobile telephones and their base stations could lead to adverse health consequences, especially in children. As a result, the construction of new power lines and broadcasting and mobile telephone network has met with considerable opposition in many countries. Public exposure to EMF is regulated by a variety of voluntary and legal limits, together with various national safety standards. Guidelines are designed to avoid all identified hazards, from short and long term exposure, recommended limits. The aim of this paper is to report the summary of the actual scientific knowledge about the potential health effects and hazards due to man made EMF and the new tendencies of the social and political choices [it

  17. Photoionization pathways and thresholds in generation of Lyman-α radiation by resonant four-wave mixing in Kr-Ar mixture

    OpenAIRE

    Oleg A. Louchev; Norihito Saito; Yu Oishi; Koji Miyazaki; Kotaro Okamura; Jumpei Nakamura; Masahiko Iwasaki; Satoshi Wada

    2016-01-01

    We develop a set of analytical approximations for the estimation of the combined effect of various photoionization processes involved in the resonant four-wave mixing generation of ns pulsed Lyman-α (L-α) radiation by using 212.556 nm and 820-845 nm laser radiation pulses in Kr-Ar mixture: (i) multi-photon ionization, (ii) step-wise (2+1)-photon ionization via the resonant 2-photon excitation of Kr followed by 1-photon ionization and (iii) laser-induced avalanche ionization produced by genera...

  18. Advanced magnetic resonance imaging methods for planning and monitoring radiation therapy in patients with high-grade glioma.

    Science.gov (United States)

    Lupo, Janine M; Nelson, Sarah J

    2014-10-01

    This review explores how the integration of advanced imaging methods with high-quality anatomical images significantly improves the characterization, target definition, assessment of response to therapy, and overall management of patients with high-grade glioma. Metrics derived from diffusion-, perfusion-, and susceptibility-weighted magnetic resonance imaging in conjunction with magnetic resonance spectroscopic imaging, allows us to characterize regions of edema, hypoxia, increased cellularity, and necrosis within heterogeneous tumor and surrounding brain tissue. Quantification of such measures may provide a more reliable initial representation of tumor delineation and response to therapy than changes in the contrast-enhancing or T2 lesion alone and have a significant effect on targeting resection, planning radiation, and assessing treatment effectiveness. In the long term, implementation of these imaging methodologies can also aid in the identification of recurrent tumor and its differentiation from treatment-related confounds and facilitate the detection of radiationinduced vascular injury in otherwise normal-appearing brain tissue.

  19. Genomic instability and radiation effects

    International Nuclear Information System (INIS)

    Christian Streffer

    2007-01-01

    Complete text of publication follows. Cancer, genetic mutations and developmental abnormalities are apparently associated with an increased genomic instability. Such phenomena have been frequently shown in human cancer cells in vitro and in situ. It is also well-known that individuals with a genetic predisposition for cancer proneness, such as ataxia telangiectesia, Fanconi anaemia etc. demonstrate a general high genomic instability e.g. in peripheral lymphocytes before a cancer has developed. Analogous data have been found in mice which develop a specific congenital malformation which has a genetic background. Under these aspects it is of high interest that ionising radiation can increase the genomic instability of mammalian cells after exposures in vitro an in vivo. This phenomenon is expressed 20 to 40 cell cycles after the exposure e.g. by de novo chromosomal aberrations. Such effects have been observed with high and low LET radiation, high LET radiation is more efficient. With low LET radiation a good dose response is observed in the dose range 0.2 to 2.0 Gy, Recently it has been reported that senescence and genomic instability was induced in human fibroblasts after 1 mGy carbon ions (1 in 18 cells are hit), apparently bystander effects also occurred under these conditions. The instability has been shown with DNA damage, chromosomal aberrations, gene mutation and cell death. It is also transferred to the next generation of mice with respect to gene mutations, chromosomal aberrations and congenital malformations. Several mechanisms have been discussed. The involvement of telomeres has gained interest. Genomic instability seems to be induced by a general lesion to the whole genome. The transmission of one chromosome from an irradiated cell to an non-irradiated cell leads to genomic instability in the untreated cells. Genomic instability increases mutation rates in the affected cells in general. As radiation late effects (cancer, gene mutations and congenital

  20. Notes on radiation effects on materials

    International Nuclear Information System (INIS)

    Anno, J.N.

    1984-01-01

    The effects of radiation from nuclear reactions on various classes of materials are examined in an introductory textbook for students of nuclear engineering. Topics discussed include the units and general scale of radiation damage, fundamental interactions of neutrons and gamma rays with materials, transient radiation effects on electrical components, radiation effects on organic materials and on steels, nuclear fission effects, surface effects of nuclear radiations, radiation effects on biological material, and neutron and gamma-ray dosimetry. Graphs, diagrams, tables of numerical data, and problems for each chapter are provided. 122 references

  1. Thermal effects in radiation processing

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    1985-01-01

    The balance of ionizing radiation energy incident on an object being processed is discussed in terms of energy losses, influencing the amount really absorbed. To obtain the amount of heat produced, the absorbed energy is corrected for the change in internal energy of the system and for the heat effect of secondary reactions developing after the initiation. The temperature of a processed object results from the heat evolved and from the specific heat of the material comprising the object. The csub(p) of most materials is usually much lower than that of aqueous systems and therefore temperatures after irradiation are higher. The role of low specific heat in radiation processing at cryogenic conditions is stressed. Adiabatic conditions of accelerator irradiation are contrasted with the steady state thermal conditions prevailing in large gamma sources. Among specific questions discussed in the last part of the paper are: intermediate and final temperature of composite materials, measurement of real thermal effects in situ, neutralization of undesired warming experienced during radiation processing, processing at temperatures other than ambient and administration of very high doses of radiation. (author)

  2. Radiation effects in silicate glasses

    International Nuclear Information System (INIS)

    Bibler, N.E.; Howitt, D.G.

    1988-01-01

    The study of radiation effects in complex silicate glasses has received renewed attention because of their use in special applications such as high level nuclear waste immobilization and fiber optics. Radiation changes the properties of these glasses by altering their electronic and atomic configurations. These alterations or defects may cause dilatations or microscopic phase changes along with absorption centers that limit the optical application of the glasses. Atomic displacements induced in the already disordered structure of the glasses may affect their use where heavy irradiating particles such as alpha particles, alpha recoils, fission fragments, or accelerated ions are present. Large changes (up to 1%) in density may result. In some cases the radiation damage may be severe enough to affect the durability of the glass in aqueous solutions. In the paper, the authors review the literature concerning radiation effects on density, durability, stored energy, microstructure and optical properties of silicate glasses. Both simple glasses and complex glasses used for immobilization of nuclear waste are considered

  3. Thermal effects in radiation processing

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    1984-01-01

    The balance of ionizing radiation energy incident on an object being processed is discussed in terms of energy losses, influencing the amount really absorbed. To obtain the amount of heat produced, the absorbed energy is corrected for the change in internal energy of the system and for the heat effect of secondary reactions developing after the initiation. The temperature of a processed object results from the heat evolved and from the specific heat of the material comprising the object. The specific heat of most materials is usually much lower than that of aqueous systems and therefore temperatures after irradiation are higher. The role of low specific heat in radiation processing at cryogenic conditions is stressed. Adiabatic conditions of accelerator irradiation are contrasted with the steady state thermal conditions prevailing in large gamma sources. Among specific questions discussed in the last part of the paper are: intermediate and final temperature of composite materials, measurement of real thermal effects in situ, neutralization of undesired warming experienced during radiation processing, processing at temperatures other than ambient and administration of very high doses of radiation

  4. Health effects of radiation and the implications for radiation safety

    International Nuclear Information System (INIS)

    Gonzalez, A.J.; Anderer, J.

    1991-01-01

    In this Paper two elements of a multiphase analysis of radiation exposures in the living environment - the human health effects of ionizing radiation and the implications for radiation safety policy and practices - are presented. Part 1 draws together the current state of scientific knowledge and insight about the human health effects of radiation, describing these in terms of known cause-related deterministic effects and of the estimated incidence of stochastic effects as defined by biostatistics and biological models. The 1988 UNSCEAR report provides an authoritative basis for such an examination. Part 2 explores some of the major implications that the state-of-the-art of radiation biology has - or should have - for radiation safety policy and practices. (author)

  5. Research on radiation effect and radiation protection at JAEA

    International Nuclear Information System (INIS)

    Saito, Kimiaki

    2007-01-01

    Researches on radiation effect and radiation protection at JAEA have been carried out in different sections. In recent years, the organizations were rearranged to attain better research circumstances, and new research programs started. At present, radiation effect studies focus on radiation effect mechanisms at atomic, molecular and cellular levels including simulation studies, and protection studies focus on dosimetry for conditions difficult to cover with currently used methods and data as well as the related basic studies. The outlines of the whole studies and also some descriptions on selected subjects will be given in this paper. (author)

  6. Radiation-Induced Alterations in Mouse Brain Development Characterized by Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Gazdzinski, Lisa M.; Cormier, Kyle; Lu, Fred G.; Lerch, Jason P.; Wong, C. Shun; Nieman, Brian J.

    2012-01-01

    Purpose: The purpose of this study was to identify regions of altered development in the mouse brain after cranial irradiation using longitudinal magnetic resonance imaging (MRI). Methods and Materials: Female C57Bl/6 mice received a whole-brain radiation dose of 7 Gy at an infant-equivalent age of 2.5 weeks. MRI was performed before irradiation and at 3 time points following irradiation. Deformation-based morphometry was used to quantify volume and growth rate changes following irradiation. Results: Widespread developmental deficits were observed in both white and gray matter regions following irradiation. Most of the affected brain regions suffered an initial volume deficit followed by growth at a normal rate, remaining smaller in irradiated brains compared with controls at all time points examined. The one exception was the olfactory bulb, which in addition to an early volume deficit, grew at a slower rate thereafter, resulting in a progressive volume deficit relative to controls. Immunohistochemical assessment revealed demyelination in white matter and loss of neural progenitor cells in the subgranular zone of the dentate gyrus and subventricular zone. Conclusions: MRI can detect regional differences in neuroanatomy and brain growth after whole-brain irradiation in the developing mouse. Developmental deficits in neuroanatomy persist, or even progress, and may serve as useful markers of late effects in mouse models. The high-throughput evaluation of brain development enabled by these methods may allow testing of strategies to mitigate late effects after pediatric cranial irradiation.

  7. Radiation-Induced Alterations in Mouse Brain Development Characterized by Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gazdzinski, Lisa M.; Cormier, Kyle [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Lu, Fred G. [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada); Lerch, Jason P. [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); Wong, C. Shun [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Nieman, Brian J., E-mail: bjnieman@phenogenomics.ca [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada)

    2012-12-01

    Purpose: The purpose of this study was to identify regions of altered development in the mouse brain after cranial irradiation using longitudinal magnetic resonance imaging (MRI). Methods and Materials: Female C57Bl/6 mice received a whole-brain radiation dose of 7 Gy at an infant-equivalent age of 2.5 weeks. MRI was performed before irradiation and at 3 time points following irradiation. Deformation-based morphometry was used to quantify volume and growth rate changes following irradiation. Results: Widespread developmental deficits were observed in both white and gray matter regions following irradiation. Most of the affected brain regions suffered an initial volume deficit followed by growth at a normal rate, remaining smaller in irradiated brains compared with controls at all time points examined. The one exception was the olfactory bulb, which in addition to an early volume deficit, grew at a slower rate thereafter, resulting in a progressive volume deficit relative to controls. Immunohistochemical assessment revealed demyelination in white matter and loss of neural progenitor cells in the subgranular zone of the dentate gyrus and subventricular zone. Conclusions: MRI can detect regional differences in neuroanatomy and brain growth after whole-brain irradiation in the developing mouse. Developmental deficits in neuroanatomy persist, or even progress, and may serve as useful markers of late effects in mouse models. The high-throughput evaluation of brain development enabled by these methods may allow testing of strategies to mitigate late effects after pediatric cranial irradiation.

  8. Investigation of some parameters influencing the sensitivity of human tooth enamel to gamma radiation using electron paramagnetic resonance

    International Nuclear Information System (INIS)

    El-Faramawy, N.

    2008-01-01

    Electron paramagnetic resonance (EPR) has been successfully used as a physical technique for gamma radiation dose reconstruction using calcified tissues. To minimize potential discrepancies between EPR readings in future studies, the effects of cavity response factor, tooth position and donor gender on the estimated gamma radiation dose were studied. It was found that the EPR response per sample mass used for assessment of doses in teeth outside of the 70-100 mg range should be corrected by a factor which is a function of the sample mass. In the EPR measurements, the difference in sensitivity of different tooth positions to γ-radiation was taken into consideration. It was determined that among all the premolars and molars tooth positions, the relative standard deviation of sensitivity was 6.5%, with the wisdom teeth and the first molars having the highest and lowest sensitivity to γ-radiation, respectively. The current results reveal no effect of the donor gender on the sensitivity to γ-radiation. (author)

  9. Health effects of radiation damage

    International Nuclear Information System (INIS)

    Gasimova, K; Azizova, F; Mehdieva, K.

    2012-01-01

    Full text : A summary of the nature of radiactive contamination would be incomplete without some mention of the human health effects relatied to radioactivity and radioactive materials. Several excellent reviews at the variety of levels of detail have been written and should be consulted by the reader. Internal exposures of alpha and beta particles are important for ingested and inhaled radionuclides. Dosimetry models are used to estimate the dose from internally deposited radioactive particles. As mentioned above weighting parameters that take into account the radiation type, the biological half-life and the tissue or organ at risk are used to convert the physically absorbed dose in units of gray (or red) to the biologically significant committed equivalent dose and effective dose, measured in units of Sv (or rem). There is considerable controversy over the shape of the dose-response curve at the chronic low dose levels important for enviromental contamination. Proposed models include linear models, non-linear models and threshold models. Because risks at low dose must be extrapolated from available date at high doses, the shape of the dose-response curve has important implications for the environmental regulations used to protect the general public. The health effect of radiation damage depends on a combination of events of on the cellular, tissue and systemic levels. These lead to mutations and cellular of the irradiated parent cell. The dose level at which significant damage occurs depends on the cell type. Cells that reproduce rapidily, such as those found in bone marrow or the gastrointestinal tract, will be more sensitive to radiation than those that are longer lived, such as striated muscle or nerve cells. The effects of high radiation doses on an organ depends on the various cell types it contains

  10. Spin and time-resolved magnetic resonance in radiation chemistry. Recent developments and perspectives

    International Nuclear Information System (INIS)

    Shkrob, I.A.; Trifunac, A.D.

    1997-01-01

    Time-resolved pulsed EPR and ODMR in studies on early events in radiation chemistry are examined. It is concluded that these techniques yield valuable and diverse information about chemical reactions in spurs, despite the fact that the spur reactions occur on a time scale that is much shorter than the time resolution of these methods. Several recent examples include EPR of H/D atoms in vitreous silica and cryogenic liquids and ODMR of doped alkane solids and amorphous semiconductors. It is argued that a wider use of time-resolved magnetic resonance methods would benefit the studies on radiation chemistry of disordered solids, simple liquids, and polymers. (author)

  11. Radiation-induced frequency transients in AT, BT, and SC cut quartz resonators

    International Nuclear Information System (INIS)

    Koehler, D.R.

    1979-01-01

    Earlier studies of transient frequency changes in high-purity swept AT quartz resonators led to the conclusion that impurity-induced effects were small, while the observed changes were qualitatively and quantitatively well characterized in terms of the time changing temperature of the vibrating quartz and its effect on frequency. 5 MHz, AT cut fifth overtone, and BT and SC cut third overtone resonators were prepared from a single stone of Sawyer swept Premium-Q quartz. The resonators were operated in precision ovenized oscillators at or near their turnover temperatures. Pulsed irradiation, at dose levels of the order of 10 4 rads (Si) per pulse, was accomplished at Sandia. The experimental data display negative frequency transients for the AT cut resonators, positive frequency transients for the BT cut resonators, and very small transient effects for the SC cut resonators. From these experimental results, it is concluded that no measurable impurity-induced frequency changes are observed in this high-purity swept-quartz and that the frequency transients are accurately modelled in terms of transient temperature effects stemming from the thermal characteristics of the resonator structure

  12. Radiation Dose–Dependent Hippocampal Atrophy Detected With Longitudinal Volumetric Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Seibert, Tyler M.; Karunamuni, Roshan [Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California (United States); Bartsch, Hauke [Department of Radiology, University of California, San Diego, La Jolla, California (United States); Kaifi, Samar [Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California (United States); Krishnan, Anitha Priya [Department of Radiology, University of California, San Diego, La Jolla, California (United States); Dalia, Yoseph; Burkeen, Jeffrey; Murzin, Vyacheslav; Moiseenko, Vitali [Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California (United States); Kuperman, Joshua; White, Nathan S. [Department of Radiology, University of California, San Diego, La Jolla, California (United States); Brewer, James B. [Department of Radiology, University of California, San Diego, La Jolla, California (United States); Department of Neurosciences, University of California, San Diego, La Jolla, California (United States); Farid, Nikdokht [Department of Radiology, University of California, San Diego, La Jolla, California (United States); McDonald, Carrie R. [Department of Psychiatry, University of California, San Diego, La Jolla, California (United States); Hattangadi-Gluth, Jona A., E-mail: jhattangadi@ucsd.edu [Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California (United States)

    2017-02-01

    Purpose: After radiation therapy (RT) to the brain, patients often experience memory impairment, which may be partially mediated by damage to the hippocampus. Hippocampal sparing in RT planning is the subject of recent and ongoing clinical trials. Calculating appropriate hippocampal dose constraints would be improved by efficient in vivo measurements of hippocampal damage. In this study we sought to determine whether brain RT was associated with dose-dependent hippocampal atrophy. Methods and Materials: Hippocampal volume was measured with magnetic resonance imaging (MRI) in 52 patients who underwent fractionated, partial brain RT for primary brain tumors. Study patients had high-resolution, 3-dimensional volumetric MRI before and 1 year after RT. Images were processed using software with clearance from the US Food and Drug Administration and Conformité Européene marking for automated measurement of hippocampal volume. Automated results were inspected visually for accuracy. Tumor and surgical changes were censored. Mean hippocampal dose was tested for correlation with hippocampal atrophy 1 year after RT. Average hippocampal volume change was also calculated for hippocampi receiving high (>40 Gy) or low (<10 Gy) mean RT dose. A multivariate analysis was conducted with linear mixed-effects modeling to evaluate other potential predictors of hippocampal volume change, including patient (random effect), age, hemisphere, sex, seizure history, and baseline volume. Statistical significance was evaluated at α = 0.05. Results: Mean hippocampal dose was significantly correlated with hippocampal volume loss (r=−0.24, P=.03). Mean hippocampal volume was significantly reduced 1 year after high-dose RT (mean −6%, P=.009) but not after low-dose RT. In multivariate analysis, both RT dose and patient age were significant predictors of hippocampal atrophy (P<.01). Conclusions: The hippocampus demonstrates radiation dose–dependent atrophy after treatment for brain

  13. Decay of giant resonances states in radiative pion capture by 1p shell nuclei

    International Nuclear Information System (INIS)

    Dogotar, G.E.

    1978-01-01

    The decay of the giant resonance states excited in tthe radiative pion capture on the 9 Be, 11 B, 13 C and 14 N nuclei is considered in the shell model with intermediate coupling. It is shown that the excited states in the daughter nuclei (A-1, Z-1) are mainly populated by intermediate states with spin by two units larger than the spin of the target nuclei. Selected coincidence experiments are proposed

  14. Synchrotron radiation in the Far-Infrared: Adsorbate-substrate vibrations and resonant interactions

    International Nuclear Information System (INIS)

    Hoffmann, F.M.; Williams, G.P.; Hirschmugl, C.J.; Chabal, Y.J.

    1991-01-01

    Synchrotron radiation in the Far Infrared offers the potential for a broadband source of high brightness and intensity. Recent development of a Far-Infrared Beamline at the NSLS in Brookhaven provides an unique high intensity source in the FIR spectral range (800-10 cm -1 ). This talk reviews its application to surface vibrational spectroscopy of low frequency adsorbate-substrate vibrations and resonant interactions on metal surfaces

  15. Genetic and somatic effects of ionizing radiation

    International Nuclear Information System (INIS)

    1986-01-01

    This is the ninth substantive report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) to the General Assembly. This report contains reviews on three special topics in the field of biological effects of ionizing radiation that are among those presently under consideration by the Committee: genetic effects of radiation, dose-response relationships for radiation-induced cancer and biological effects of pre-natal irradiation

  16. The use of manganese-enhanced magnetic resonance imaging in rat radiation-induced optic neuropathy

    International Nuclear Information System (INIS)

    Guan Xiyin; Wang Jiazhou; Zhou Lijun; Zhu Guopei

    2014-01-01

    Objective: To establish a rat model of radiation-induced optic neuropathy (RION) by delivering a single radiation dose to the optic chiasm. The aim of our study was to analysis the feasibility and effectiveness of manganese-enhanced magnetic resonance imaging (MEMRI) in RION. Methods: 34 Wistar rats were randomized to the control group(4 rats), the 2-month group(5 rats), the 4-month group(4 rats) and the 6-month group(11 rats) according to the different feeding period after irradiation. MEMRI scan were performed when the respective feeding periods of all groups expired. The rats were then killed for histological studies with hematoxylin and eosin stain, Luxol Fast Blue stain, and electron microscopy analysis. Results: The ratio of RION in the four groups were 0/3, 1/5, 2/4 and 11/11, respectively(χ"2 = 15.443, P < 0.05). There was an inverse correlation between the relative optical density value in the LFB stain and the interval between irradiation and pathological examination(R = -0.643, P < 0.05). The number of glial cells in the HE stain in the four groups were 194±65, 234±19, 124±11 and 345±98, respectively(R = 0.590, P < 0.05). When compared MEMRI scan with the corresponding histological examination, we found that there was loss of signals of optic nerve on MEMRI imaging in one of 5 rats in the 2-month group, while no significant histological difference was found between this rat and the others. Conclusions: RION can be non-invasively detected and semi-quantitative analysed by MEMRI scan. Moreover, RION can be early diagnosed by MEMRI scan which is capable to show physiological change in advance of pathological change. (authors)

  17. Formation of H_2^+ and its Isotopomers by Radiative Association: the Role of Shape and Feshbach Resonances

    Science.gov (United States)

    Beyer, Maximilian; Merkt, Frederic

    2017-06-01

    The recent observations [1,2] of shape and Feshbach resonances in the high-resolution photoelectron spectra of H_2, HD and D_2 in the vicinity of the dissociation thresholds of H_2^+, HD^+ and D_2^+ raise questions concerning their potential role in the formation of H_2^+ and its isotopomers in the early universe by radiative association, a topic of astrophysical interest [3]. Close-coupling calculations for the cross sections of the reactions {H}^+ + {H} &\\to {H}_2^+ + hν {H}^+ + {D} &\\to {HD}^+ + hν {D}^+ + {H} &\\to {HD}^+ + hν {D}^+ + {D} &\\to {D}_2^+ + hν, will be presented which take into account nonadiabatic couplings involving rovibronic and hyperfine interactions, as well as relativistic and radiative corrections. The calculated energies and widths will be compared with the experimental results of Ref. [1,2] for H_2^+ and new data for HD^+ and D_2^+. The effect of the resonances on the radiative association rate coefficients will be discussed, also in comparison with earlier studies [4]. [1] M. Beyer and F. Merkt, Phys. Rev. Lett. 116, 093001 (2016). [2] M. Beyer and F. Merkt, J. Mol. Spectrosc. 330, 147 (2016). [3] Molecule formation in dust-poor environments, J. F. Babb and K. P. Kirby, in "The molecular astrophysics of stars and galaxies", T. W. Hartquist and D. A. Williams, eds., Oxford University Press, Oxford, 1998, pp. 11-34. [4] D. E. Ramaker and J. M. Peek, Phys. Rev. A 13, 58 (1976).

  18. Simulation of Helmholtz Resonance Effects in Aircraft ECS

    OpenAIRE

    Pollok, Alexander; Schröffer, Andreas

    2017-01-01

    Helmholtz resonators are closed volumes that are connected to pipes. They exhibit a pronounced resonance frequency, where small boundary pressure excitations in the volume or the environment lead to large mass flow excitations in the pipe. Aircraft have a topology similar to Helmholtz resonators, the closed volume is represented by the cabin, while the pipe is represented by the Environmental Control System. Some discrepancies appear due to the non-zero mass-flow or friction effects in...

  19. Towards radiation detected resonance ionization spectroscopy on transfermium elements in a buffer gas cell

    Energy Technology Data Exchange (ETDEWEB)

    Lautenschlaeger, Felix; Walther, Thomas [Institut fuer Angewandte Physik, TU Darmstadt, 64289 Darmstadt (Germany); Laatiaoui, Mustapha; Block, Michael [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Helmholtz-Institut Mainz, 55128 Mainz (Germany); Lauth, Werner; Backe, Hartmut [Institut fuer Kernphysik, JGU Mainz, 55128 Mainz (Germany); Hessberger, Fritz-Peter [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany)

    2013-07-01

    The study of the atomic structure of transfermium elements like nobelium (No) and lawrencium (Lr) via Radiation Detected Resonance Ionization Spectroscopy (RADRIS) is one of the most fascinating disciplines of modern atomic physics. It allows the determination of relativistic effects at the heaviest elements and provides a critical test of theoretical predictions. For these transfermium elements no experimental data on atomic level schemes are available at present. First experiments on {sup 254}No were performed in 2007, in which a buffer gas cell with an overall efficiency of 1%. In this experiment the evaporation temperature of nobelium was determined for the first time. To increase the efficiency of the buffer gas cell, off-line measurements have been performed with nat. ytterbium, the chemical homologue of nobelium. Also on-line experiments during a parasitic beam-time in 2012 provided an insight into the critical parameters of our setup. The results of the off-line and on-line measurements are briefly summarized in this talk.

  20. Ionising radiation - physical and biological effects

    International Nuclear Information System (INIS)

    Holter, Oe.; Ingebretsen, F.; Parr, H.

    1979-01-01

    The physics of ionising radiation is briefly presented. The effects of ionising radiation on biological cells, cell repair and radiosensitivity are briefly treated, where after the effects on man and mammals are discussed and related to radiation doses. Dose limits are briefly discussed. The genetic effects are discussed separately. Radioecology is also briefly treated and a table of radionuclides deriving from reactors, and their radiation is given. (JIW)

  1. Radiation effects on microelectronics in space

    International Nuclear Information System (INIS)

    Srour, J.R.; McGarrity, J.M.

    1988-01-01

    The basic mechanisms of space radiation effects on microelectronics are reviewed in this paper. Topics discussed include the effects of displacement damage and ionizing radiation on devices and circuits, single event phenomena, dose enhancement, radiation effects on optoelectronic devices and passive components, hardening approaches, and simulation of the space radiation environment. A summary is presented of damage mechanisms that can cause temporary or permanent failure of devices and circuits operating in space

  2. Effect of radiation in radiotherapy

    International Nuclear Information System (INIS)

    Hirata, Hideki; Fujibuchi, Toshio; Saito, Tsutomu

    2013-01-01

    The title subject is easily explained for the deterministic effect, secondary cancer formation and case reports of accidental exposure at radiotherapy. For the deterministic effect, the dose-effect relationship is sigmoidal in normal and cancer tissues, and the more separated are their curves, the more favorable is the radiotherapy. TD 5/5 is the tolerable dose to yield <5% of irreversible radiation injury to the normal tissue within 5 years after the therapy and is generally dose-limiting. The curves are of various shapes depending on the tissue composition that its functional subunit (FSU) is parallel like lobules of the liver, or in series like neuron. Symptoms appear complicated on these factors. Recent development of CT-based therapeutic planning has made it possible to analyze the partial tissue volume to be irradiated and its absorbed dose by the relationship (dose volume histogram, DVH) between the electron density vs CT value regardless to anatomy. The normal tissue complication probability is a model composed from the physical DVH and biological factors of FSU composition and cellular radiation susceptibility, and is a measure of the irreversible late effect manifested in normal tissues. Epidemiology has shown the increased risk of secondary cancer formation by radiotherapy. Children are highly susceptible to this, and in adults undergoing the therapy of a certain cancer, it is known that the risk of radiation carcinogenesis is increased in the particular tissue. There are presented such case reports of accidental excessive exposure at radiotherapy as caused by an inappropriate use of detector, partial loss of data in a therapeutic planning device, reading of reversed MRI image, and too much repeated use of the old-type electric portal imaging device. (T.T.)

  3. Radiation Effects in Nuclear Ceramics

    Directory of Open Access Journals (Sweden)

    L. Thomé

    2012-01-01

    Full Text Available Due to outstanding physicochemical properties, ceramics are key engineering materials in many industrial domains. The evaluation of the damage created in ceramics employed in radiative media is a challenging problem for electronic, space, and nuclear industries. In this latter field, ceramics can be used as immobilization forms for radioactive wastes, inert fuel matrices for actinide transmutation, cladding materials for gas-cooled fission reactors, and structural components for fusion reactors. Information on the radiation stability of nuclear materials may be obtained by simulating the different types of interactions involved during the slowing down of energetic particles with ion beams delivered by various types of accelerators. This paper presents a review of the radiation effects occurring in nuclear ceramics, with an emphasis on recent results concerning the damage accumulation processes. Energetic ions in the KeV-GeV range are used to explore the nuclear collision (at low energy and electronic excitation (at high energy regimes. The recovery by electronic excitation of the damage created by ballistic collisions (SHIBIEC process is also addressed.

  4. Resonant Effects in Neutral beam Moderation at TJ-II

    International Nuclear Information System (INIS)

    Guasp, J.; Liniers, M.; Fuentes, C.

    1999-01-01

    The structure of fast ion losses in neutral beam moderation at TJ-II is analysed theoretically, in particular the influence of resonant effects and the radial electric field dependence. The direct losses show strong resonant effects when the ratio of the poloidal and toroidal rotation velocities pass near the values -4/3, -2 or 0. These effects are visible as strong maxima on the loss fractions and also as characteristic trajectory behaviours. The delayed losses present resonant effects also, generally at intermediate energies (5 to 20 KeV for 40 keV injection). Near the resonances the population of passing particles in these losses is very high and the loss fraction can equal or even surpass the direct losses. In these delayed losses the particles concentrate along vertical strips on the loss cone diagrams of roughly constant parallel velocity. This parallel velocity increases with the electric field, the loss maxima are reached usually when the pitch and energy of these strips are near the initial injection values. The trapped particle population in these delayed losses is maximal at null electric and decreases with the field intensity for both potential signs. The corresponding final energies are usually low (1 to 5 keV). Except at extreme potentials, where the -4 resonance can appear, no resonant effects are observed for this population. The resonance ordering is similar for all configurations and follows reasonably the predictions of a simple model. The extreme configurations are dominated by the effects of the 0 and -2 resonances, giving very high loss fractions even for null electric field. In contrast the intermediate configurations, near the Reference one, do not present resonant effects and the losses are moderate at low potentials. Only above 2000 v the resonant effects start to appear. (Author) 11 refs

  5. Detection of radiation induced lung injury in rats using dynamic hyperpolarized 129Xe magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Fox, Matthew S.; Ouriadov, Alexei; Hegarty, Elaine; Thind, Kundan; Wong, Eugene; Hope, Andrew; Santyr, Giles E.

    2014-01-01

    Purpose: Radiation induced lung injury (RILI) is a common side effect for patients undergoing thoracic radiation therapy (RT). RILI can lead to temporary or permanent loss of lung function and in extreme cases, death. Combining functional lung imaging information with conventional radiation treatment plans may lead to more desirable treatment plans that reduce lung toxicity and improve the quality of life for lung cancer survivors. Magnetic Resonance Imaging of the lung following inhalation of hyperpolarized 129 Xe may provide a useful nonionizing approach for probing changes in lung function and structure associated with RILI before, during, or after RT (early and late time-points). Methods: In this study, dynamic 129 Xe MR spectroscopy was used to measure whole-lung gas transfer time constants for lung tissue and red blood cells (RBC), respectively (T Tr-tissue and T Tr-RBC ) in groups of rats at two weeks and six weeks following 14 Gy whole-lung exposure to radiation from a 60 Co source. A separate group of six healthy age-matched rats served as a control group. Results: T Tr-tissue values at two weeks post-irradiation (51.6 ± 6.8 ms) were found to be significantly elevated (p < 0.05) with respect to the healthy control group (37.2 ± 4.8 ms). T Tr-RBC did not show any significant changes between groups. T Tr-tissue was strongly correlated with T Tr-RBC in the control group (r = 0.9601 p < 0.05) and uncorrelated in the irradiated groups. Measurements of arterial partial pressure of oxygen obtained by arterial blood sampling were found to be significantly decreased (p < 0.05) in the two-week group (54.2 ± 12.3 mm Hg) compared to those from a representative control group (85.0 ± 10.0 mm Hg). Histology of a separate group of similarly irradiated animals confirmed the presence of inflammation due to radiation exposure with alveolar wall thicknesses that were significantly different (p < 0.05). At six weeks post-irradiation, T Tr-tissue returned to values (35

  6. The Dependence of the Resonance Integral on the Doppler Effect

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, J

    1960-12-15

    The Doppler sensitive contributions to the resonance integral for metal and oxide cylinders have been calculated using tables compiled by Adler, Hinman and Nordheim. The temperatures 20, 200, 350, 500 and 650 deg C have been investigated for the pure metal and 20, 300, 600, 900 and 1200 deg C for the oxide. Contributions from the separate resonances in the resolved region and for certain energies in the unresolved region are accounted for in detail. Integration over adequate statistical distributions has been carried out for the resonance parameters in the unresolved region. The increase in the resonance integral at elevated temperatures due to the Doppler effect is given separately in tables and diagrams.

  7. Evaluation of the radiation width of the 27.7 keV resonance in 56Fe

    International Nuclear Information System (INIS)

    Allen, B.J.

    1982-01-01

    A critical review is given of measurements of the radiation width of the 27.7 keV resonance in 56 Fe. An evaluation of results yields a recommended value of GAMMA #betta# + 1.00 +- 0.04 eV for this resonance

  8. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  9. Radiation effects on cell membranes

    International Nuclear Information System (INIS)

    Koeteles, G.J.

    1982-01-01

    The recent developments in the field of membrane biology of eukaryotic cells result in revival of relevant radiobiological studies. The spatial relations and chemical nature of membrane components provide rather sensitive targets. Experimental data are presented concerning the effects of relatively low doses of X-irradiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus - of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the multifold roles of radiationinduced membrane phenomena on the development and regeneration of radiation injuries. (orig.)

  10. Radiation effects on cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Koeteles, G.J.

    1982-11-01

    The recent developments in the field of membrane biology of eukaryotic cells result in revival of relevant radiobiological studies. The spatial relations and chemical nature of membrane components provide rather sensitive targets. Experimental data are presented concerning the effects of relatively low doses of X-irradiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus - of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the multifold roles of radiationinduced membrane phenomena on the development and regeneration of radiation injuries.

  11. Effect of radiation on food

    Energy Technology Data Exchange (ETDEWEB)

    Sofyan, R [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1983-07-01

    Research reports on the effect on radiation on food are reviewed. Irradiation processing inhibits the sprouting of vegetables, delays ripening, reduces the number of microorganisms that spoil food, controls patrogenic organisms and parasites found in food, disinfests food of insects, and disinfects spices of microbes. So far there has been no evidence that food irradiaton introduces nutritional or microbiological problems. The FAO/WHO/IAEA expert committee on the wholesomeness of irradiated food recommend the acceptability from a toxicological stand-point of any food commodity irradiated up to an overall average dose of 10 kilograys.

  12. Effect of radiation on food

    International Nuclear Information System (INIS)

    Sofyan, Rochestri

    1983-01-01

    Research reports on the effect on radiation on food are reviewed. Irradiation processing inhibits the sprouting of vegetables, delays ripening, reduces the number of microorganisms that spoil food, controls patrogenic organisms and parasites found in food, disinfests food of insects, and disinfects spices of microbes. So far there has been no evidence that food irradiaton introduces nutritional or microbiological problems. The FAO/WHO/IAEA expert committee on the wholesomeness of irradiated food recommend the acceptability from a toxicological stand-point of any food commodity irradiated up to an overall average dose of 10 kilograys. (RUW)

  13. Effects of radiation upon gastrointestinal motility

    Institute of Scientific and Technical Information of China (English)

    Mary F Otterson

    2007-01-01

    Whether due to therapeutic or belligerent exposure, the gastrointestinal effects of irradiation produce symptoms dreaded by a majority of the population. Nausea, vomiting, diarrhea and abdominal cramping are hallmarks of the prodromal phase of radiation sickness, occurring hours to days following radiation exposure. The prodromal phase is distinct from acute radiation sickness in that the absorptive, secretory and anatomic changes associated with radiation damage are not easily identifiable. It is during this phase of radiation sickness that gastrointestinal motility significantly changes. In addition, there is evidence that motor activity of the gut contributes to some of the acute and chronic effects of radiation.

  14. The Brookhaven Radiation Effects Facility

    Energy Technology Data Exchange (ETDEWEB)

    Grand, P.; Snead, C.L.; Ward, T.

    1988-01-01

    The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H{sup -}, H{sup o}, and H{sup +} beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 5 {mu}s to 500 {mu}s length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 {sigma}) resulting in a maximum dose of about 10 MRads (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality (LTH-4) program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives (HE). This paper describes the facility, its capabilities and potential, and the experiments that have been carried out to date or are being planned. 2 refs., 10 figs.

  15. The Brookhaven Radiation Effects Facility

    International Nuclear Information System (INIS)

    Grand, P.; Snead, C.L.; Ward, T.

    1988-01-01

    The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H - , H/sup o/, and H + beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 5 μs to 500 μs length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 σ) resulting in a maximum dose of about 10 MRads (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality (LTH-4) program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives (HE). This paper describes the facility, its capabilities and potential, and the experiments that have been carried out to date or are being planned. 2 refs., 10 figs

  16. Effects of radiation on DNA

    International Nuclear Information System (INIS)

    Braddock, M.

    1985-07-01

    The hydroxyl radical (OH radical) is the most damaging radical produced by the effect of ionizing radiation in water. The rate of reaction of the OH radical with purified, native and isodisperse DNA has been determined as compared with calf thymus DNA. This has been achieved by direct observation of the rate of formation of the DNA-OH radical adduct, and by competition with SCN - . Results obtained from direct observation are consistent with calculations which have been performed using the encounter frequency model of Braams and Ebert. However, results obtained for OH radical with DNA derived from competition plots suggest a rate constant somewhat lower than that obtained from direct observation. The relative merits of both techniques are discussed. In order to study the effect of energy deposited directly in the DNA, dry films of purified plasmid DNA have been irradiated in a system where the indirect effects of radical interaction have been minimized. The present results indicate that with different molecular lengths of plasmid DNA, non-random breakage may occur, and that additional damage may be brought about at sites of previously existing damage. Differences in the sensitivity of plasmid DNA molecules of varying lengths to radiation induced double strand breaks have been demonstrated. (author)

  17. Acoustofluidics: Theory and simulation of streaming and radiation forces at ultrasound resonances in microfluidic devices

    DEFF Research Database (Denmark)

    Bruus, Henrik

    2009-01-01

    fields, which are directly related to the acoustic radiation force on single particles and to the acoustic streaming of the liquid. For the radiation pressure effects, there is good agreement between theory and simulation, while the numeric results for the acoustic streaming effects are more problematic...

  18. Effects of ionizing radiation on vitamins

    International Nuclear Information System (INIS)

    Thayer, D.W.; Fox, J.B. Jr.; Lakritz, L.

    1991-01-01

    Vitamins are known to be sensitive to the effects of ionizing radiation. Since most foods contain a large proportion of water, the most probable reaction of the ionizing radiation would be with water; and as vitamins are present in very small amounts compared with other substances in the food they will be affected indirectly by the radiation. This chapter discusses the effect of ionizing radiation on water soluble vitamins and fat soluble vitamins. (author)

  19. Radiation effects of high and low doses

    International Nuclear Information System (INIS)

    El-Naggar, A.M.

    1998-01-01

    The extensive proliferation of the uses and applications of atomic and nuclear energy resulted in possible repercussions on human health. The prominent features of the health hazards that may be incurred after exposure to high and low radiation doses are discussed. The physical and biological factors involved in the sequential development of radiation health effects and the different cellular responses to radiation injury are considered. The main criteria and features of radiation effects of high and low doses are comprehensively outlined

  20. Medical response to effects of ionising radiation

    International Nuclear Information System (INIS)

    Crosbie, W.A.; Gittus, J.H.

    1989-01-01

    The proceedings of a conference on 'Medical Response to Effects of Ionising Radiation' in 1989 in the form of nineteen papers published as a book. Topics discussed include radiation accidents at nuclear facilities, the medical management of radiation casualties, the responsibilities, plans and resources for coping with a nuclear accident and finally the long term effects of radiation, including leukaemia epidemiology studies. All papers were selected and indexed separately. (UK)

  1. Ionic core effects on the Mie resonance in lithium clusters

    International Nuclear Information System (INIS)

    Yabana, K.

    1994-01-01

    We investigate effects of atomic cores on the Mie resonance in lithium metal clusters, perturbing a helium Hamiltonian with zero-range pseudopotentials. The resonance is red-shifted with respect to the classical formula by core effects, most important of which is the increased effective mass due to the core potentials. Much of the large shift seen in lithium clusters is thereby explained if the strength of the Pseudopotentials is taken from band structure calculations. However, such pseudopotentials cause the resonance to be greatly broadened, contrary to observation

  2. Substrate effects on terahertz metamaterial resonances for various metal thicknesses

    International Nuclear Information System (INIS)

    Park, S. J.; Ahn, Y. H.

    2014-01-01

    We demonstrate dielectric substrate effects on the resonance shift of terahertz metamaterials with various metal thicknesses by using finite-difference time-domain simulations. We found a small red shift in the metamaterial resonance with increasing metal thickness for the free-standing case. Conversely, when the metamaterial pattern was supported by a substrate with a high dielectric constant, the resonant frequency exhibited a large blue shift because the relative contribution of the substrate's refractive index to the resonant frequency decreased drastically as we increased the metal thickness. We determined the substrate's refractive index, 1.26, at which the metamaterial resonance was independent of the metal thickness. We extracted the effective refractive index as a function of the substrate's refractive index explicitly, which was noticeably different for different film thicknesses.

  3. Resonance zones and quasi-linear diffusion coefficients for radiation belt energetic electron interaction with oblique chorus waves in the Dungey magnetosphere

    International Nuclear Information System (INIS)

    Shi Run; Ni, Binbin; Gu Xudong; Zhao Zhengyu; Zhou Chen

    2012-01-01

    The resonance regions for resonant interactions of radiation belt electrons with obliquely propagating whistler-mode chorus waves are investigated in detail in the Dungey magnetic fields that are parameterized by the intensity of uniform southward interplanetary magnetic field (IMF) Bz or, equivalently, by the values of D=(M/B z,0 ) 1/3 (where M is the magnetic moment of the dipole and B z,0 is the uniform southward IMF normal to the dipole’s equatorial plane). Adoption of background magnetic field model can considerably modify the determination of resonance regions. Compared to the results for the case of D = 50 (very close to the dipole field), the latitudinal coverage of resonance regions for 200 keV electrons interacting with chorus waves tends to become narrower for smaller D-values, regardless of equatorial pitch angle, resonance harmonics, and wave normal angle. In contrast, resonance regions for 1 MeV electrons tend to have very similar spatial lengths along the field line for various Dungey magnetic field models but cover different magnetic field intervals, indicative of a strong dependence on electron energy. For any given magnetic field line, the resonance regions where chorus-electron resonant interactions can take place rely closely on equatorial pitch angle, resonance harmonics, and kinetic energy. The resonance regions tend to cover broader latitudinal ranges for smaller equatorial pitch angles, higher resonance harmonics, and lower electron energies, consistent with the results in Ni and Summers [Phys. Plasmas 17, 042902, 042903 (2010)]. Calculations of quasi-linear bounce-averaged diffusion coefficients for radiation belt electrons due to nightside chorus waves indicate that the resultant scattering rates differ from using different Dungey magnetic field models, demonstrating a strong dependence of wave-induced electron scattering effect on the adoption of magnetic field model. Our results suggest that resonant wave-particle interaction processes

  4. Radiation effects in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Begay, F.; Rosen, L.; Petersen, D.F.; Mason, C.; Travis, B. [Los Alamos National Lab., NM (United States); Yazzie, A. [Navajo Nation, Window Rock, AZ (United States). Dept. of History; Isaac, M.C.P.; Seaborg, G.T. [Lawrence Berkeley National Lab., CA (United States); Leavitt, C.P. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy

    1999-04-01

    Although the Navajo possess substantial resource wealth-coal, gas, uranium, water-this potential wealth has been translated into limited permanent economic or political power. In fact, wealth or potential for wealth has often made the Navajo the victims of more powerful interests greedy for the assets under limited Navajo control. The primary focus for this education workshop on the radiation effects in the environment is to provide a forum where scientists from the nuclear science and technology community can share their knowledge toward the advancement and diffusion of nuclear science and technology issues for the Navajo public. The scientists will make an attempt to consider the following basic questions; what is science; what is mathematics; what is nuclear radiation? Seven papers are included in this report: Navajo view of radiation; Nuclear energy, national security and international stability; ABC`s of nuclear science; Nuclear medicine: 100 years in the making; Radon in the environment; Bicarbonate leaching of uranium; and Computational methods for subsurface flow and transport. The proceedings of this workshop will be used as a valuable reference materials in future workshops and K-14 classrooms in Navajo communities that need to improve basic understanding of nuclear science and technology issues. Results of the Begay-Stevens research has revealed the existence of strange and mysterious concepts in the Navajo Language of nature. With these research results Begay and Stevens prepared a lecture entitled The Physics of Laser Fusion in the Navajo language. This lecture has been delivered in numerous Navajo schools, and in universities and colleges in the US, Canada, and Alaska.

  5. Longitudinal diffusion tensor magnetic resonance imaging study of radiation-induced white matter damage in a rat model.

    Science.gov (United States)

    Wang, Silun; Wu, Ed X; Qiu, Deqiang; Leung, Lucullus H T; Lau, Ho-Fai; Khong, Pek-Lan

    2009-02-01

    Radiation-induced white matter (WM) damage is a major side effect of whole brain irradiation among childhood cancer survivors. We evaluate longitudinally the diffusion characteristics of the late radiation-induced WM damage in a rat model after 25 and 30 Gy irradiation to the hemibrain at 8 time points from 2 to 48 weeks postradiation. We hypothesize that diffusion tensor magnetic resonance imaging (DTI) indices including fractional anisotropy (FA), trace, axial diffusivity (lambda(//)), and radial diffusivity (lambda( perpendicular)) can accurately detect and monitor the histopathologic changes of radiation-induced WM damage, measured at the EC, and that these changes are dose and time dependent. Results showed a progressive reduction of FA, which was driven by reduction in lambda(//) from 4 to 40 weeks postradiation, and an increase in lambda( perpendicular) with return to baseline in lambda(//) at 48 weeks postradiation. Histologic evaluation of irradiated WM showed reactive astrogliosis from 4 weeks postradiation with reversal at 36 weeks, and demyelination, axonal degeneration, and necrosis at 48 weeks postradiation. Moreover, changes in lambda(//) correlated with reactive astrogliosis (P histopathologic changes of WM damage and our results support the use of DTI as a biomarker to noninvasively monitor radiation-induced WM damage.

  6. Effects of ionizing radiation on life

    International Nuclear Information System (INIS)

    Rausch, L.

    1982-01-01

    Radiobiology in the last years was able to find detailed explanations for the effects of ionizing radiation on living organisms. But it is still impossible to make exact statements concerning the damages by radiation. Even now, science has to content itself with probability data. Moreover no typical damages of ionizing radiation can be identified. Therefore, the risks of ionizing radiation can only be determined by comparison with the spontaneous rate of cancerous or genetic defects. The article describes the interaction of high-energy radiation with the molecules of the organism and their consequences for radiation protection. (orig.)

  7. High-Quality T2-Weighted 4-Dimensional Magnetic Resonance Imaging for Radiation Therapy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Du, Dongsu [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Caruthers, Shelton D. [Philips Healthcare, Cleveland, Ohio (United States); Glide-Hurst, Carri [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Low, Daniel A. [Department of Radiation Oncology, University of California-Los Angeles, Los Angeles, California (United States); Li, H. Harold; Mutic, Sasa [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Hu, Yanle, E-mail: Hu.Yanle@mayo.edu [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Department of Radiation Oncology, Mayo Clinic in Arizona, Phoenix, Arizona (United States)

    2015-06-01

    Purpose: The purpose of this study was to improve triggering efficiency of the prospective respiratory amplitude-triggered 4-dimensional magnetic resonance imaging (4DMRI) method and to develop a 4DMRI imaging protocol that could offer T2 weighting for better tumor visualization, good spatial coverage and spatial resolution, and respiratory motion sampling within a reasonable amount of time for radiation therapy applications. Methods and Materials: The respiratory state splitting (RSS) and multi-shot acquisition (MSA) methods were analytically compared and validated in a simulation study by using the respiratory signals from 10 healthy human subjects. The RSS method was more effective in improving triggering efficiency. It was implemented in prospective respiratory amplitude-triggered 4DMRI. 4DMRI image datasets were acquired from 5 healthy human subjects. Liver motion was estimated using the acquired 4DMRI image datasets. Results: The simulation study showed the RSS method was more effective for improving triggering efficiency than the MSA method. The average reductions in 4DMRI acquisition times were 36% and 10% for the RSS and MSA methods, respectively. The human subject study showed that T2-weighted 4DMRI with 10 respiratory states, 60 slices at a spatial resolution of 1.5 × 1.5 × 3.0 mm{sup 3} could be acquired in 9 to 18 minutes, depending on the individual's breath pattern. Based on the acquired 4DMRI image datasets, the ranges of peak-to-peak liver displacements among 5 human subjects were 9.0 to 12.9 mm, 2.5 to 3.9 mm, and 0.5 to 2.3 mm in superior-inferior, anterior-posterior, and left-right directions, respectively. Conclusions: We demonstrated that with the RSS method, it was feasible to acquire high-quality T2-weighted 4DMRI within a reasonable amount of time for radiation therapy applications.

  8. γ radiation effects on Collembola

    International Nuclear Information System (INIS)

    Loring, S.J.

    1985-01-01

    Pitfall traps were used to collect surface-active Collembola at intervals of 10-100 m from a γ radiation source on Long Island, N.Y., during the summer of 1968. Thirty-two species of Collembola were collected along the radiation transect. Community diversities were similar at all intervals except 10 m. Collembola appeared resistant to γ radiation; only chronic, very high γ radiation exposure seriously affected population levels and community diversity of surface Collembola

  9. Effect of radiation therapy against intracranial hemangiopericytoma

    Energy Technology Data Exchange (ETDEWEB)

    Uemura, Shozaburo; Kuratsu, Jun-ichi; Hamada, Jun-ichiro; Yoshioka, Susumu; Kochi, Masato; Ushio, Yukitaka [Kumamoto Univ. (Japan). School of Medicine; Nakahara, Tadashi; Kishida, Katsuaki

    1992-06-01

    Seven cases of intracranial hemangiopericytoma were studied retrospectively to investigate the efficacy of radiation therapy. Tumor response evaluated by computed tomography and magnetic resonance imaging was obvious after 20-30 Gy irradiation. The total reduction rate was 80-90% and continued as long as 5-7 months after treatment. In five patients receiving radiation therapy before radical removal, the tumors were easily removed without massive hemorrhage. Histological inspection of specimens after irradiation showed a significant disappearance of tumor cells. Pyknosis frequently occurred in endothelial cells, and proliferating vessels with hyalinoid degeneration were also seen. Reticulin fibers between tumor cells were fewer, split, or absent. Preoperative radiation therapy is useful in the treatment of hemangiopericytoma involving considerable surgical risk. Postoperative radiation therapy should be given even if removal is complete. (author).

  10. Effect of radiation therapy against intracranial hemangiopericytoma

    International Nuclear Information System (INIS)

    Uemura, Shozaburo; Kuratsu, Jun-ichi; Hamada, Jun-ichiro; Yoshioka, Susumu; Kochi, Masato; Ushio, Yukitaka; Nakahara, Tadashi; Kishida, Katsuaki.

    1992-01-01

    Seven cases of intracranial hemangiopericytoma were studied retrospectively to investigate the efficacy of radiation therapy. Tumor response evaluated by computed tomography and magnetic resonance imaging was obvious after 20-30 Gy irradiation. The total reduction rate was 80-90% and continued as long as 5-7 months after treatment. In five patients receiving radiation therapy before radical removal, the tumors were easily removed without massive hemorrhage. Histological inspection of specimens after irradiation showed a significant disappearance of tumor cells. Pyknosis frequently occurred in endothelial cells, and proliferating vessels with hyalinoid degeneration were also seen. Reticulin fibers between tumor cells were fewer, split, or absent. Preoperative radiation therapy is useful in the treatment of hemangiopericytoma involving considerable surgical risk. Postoperative radiation therapy should be given even if removal is complete. (author)

  11. Possible resonance effect of axionic dark matter in Josephson junctions.

    Science.gov (United States)

    Beck, Christian

    2013-12-06

    We provide theoretical arguments that dark-matter axions from the galactic halo that pass through Earth may generate a small observable signal in resonant S/N/S Josephson junctions. The corresponding interaction process is based on the uniqueness of the gauge-invariant axion Josephson phase angle modulo 2π and is predicted to produce a small Shapiro steplike feature without externally applied microwave radiation when the Josephson frequency resonates with the axion mass. A resonance signal of so far unknown origin observed by C. Hoffmann et al. [Phys. Rev. B 70, 180503(R) (2004)] is consistent with our theory and can be interpreted in terms of an axion mass m(a)c2=0.11  meV and a local galactic axionic dark-matter density of 0.05  GeV/cm3. We discuss future experimental checks to confirm the dark-matter nature of the observed signal.

  12. Biologic effects of electromagnetic radiation and microwave

    International Nuclear Information System (INIS)

    Deng Hua

    2002-01-01

    Electromagnetic radiation and microwave exist mankind's environment widely. People realize they disserve authors' health when authors make use of them. Electromagnetic radiation is one of the major physic factors which injure people's health. A review of the biologic mechanism about electromagnetic radiation and microwave, their harmful effects to human body, problems in authors' research and the prospect

  13. Study of biological effect of radiation

    International Nuclear Information System (INIS)

    Li Guisheng

    1992-01-01

    The some progress on the study of biological effect for protract exposure to low dose rate radiation is reported, and it is indicated that the potential risk of this exposure for the human health and the importance of the routine monitoring of radiation dose for various nuclear installations. The potential exposure to the low dose rate radiation would attract people's extra attention

  14. Molecular and cellular effects of radiations

    International Nuclear Information System (INIS)

    Peak, M.J.; Peak, J.G.; Ito, A.; Roth, R.M.

    1985-01-01

    This program is concerned with the basic nature of the biological effects of mutagenic and carcinogenic environmental radiations, including those solar ultraviolet and visible radiations responsible for the most common form of human cancer: cancer of the skin. Concentrating on the damages to DNA caused by these radiations, the program attempts to delineate the basic mechanisms whereby such damage may occur. 14 refs

  15. Radiation effects on biochemical systems

    International Nuclear Information System (INIS)

    Seddon, G.M.

    2000-04-01

    Xanthine oxidase catalyses the oxidative hydroxylation of hypoxanthine, xanthine and a wide range of carbonyl compounds. The enzyme exists as an oxidase and a dehydrogenase; both catalyze the oxidation of the same substrates. Steady state radiolysis and pulse radiolysis were used to generate oxidative and reductive free radicals. Their effects on the enzymatic activity of xanthine oxidase were determined. Initially inactivation studies were carried out to evaluate the extent to which radiolysis in aqueous solution affects the enzyme activity. Values of D 37 and G inactivation were calculated following irradiation in the presence of free radical scavengers and in the presence of catalase and superoxide dismutase. The kinetic constants Vmax and Km were also determined following radiolysis. The effect of ionising radiation on the iron content of xanthine oxidase was measured using atomic absorption spectrometry. Native gel electrophoresis and iso-electric focussing were performed in an attempt to demonstrate changes in the overall structure of the enzyme. The binding of xanthine oxidase to heparin was carried out by measuring, (1) the displacement of methylene blue (MB + ) from a heparin-MB + complex, (2) affinity chromatography and, (3) pulse radiolysis. The effect of irradiation on the binding process was investigated using techniques (1) and (2). Finally the radiation-induced conversion of xanthine oxidase to dehydrogenase was established. The results indicate that xanthine oxidase is inactivated greatest in the presence of air and irradiation causes Vmax to he reduced and Km to increase. The iron content of irradiated xanthine oxidase is unaffected. Electrophoresis shows the enzyme becomes fragmented and the isoelectric points of the fragments vary over a wide range of pH. Binding of xanthine oxidase to heparin as measured by displacement of MB + from a heparin-MB + complex suggests that irradiation increases the affinity of the enzyme for the polyanion, whereas

  16. The effects of radiation on man

    International Nuclear Information System (INIS)

    Saunders, P.

    1981-01-01

    Available evidence on the effects of high levels of radiation on man and the predictions which have been made on possible low level effects, by extrapolation of the high level data, are summarised. The factors which influence the biological effects of radiation are examined and acute, delayed, somatic and hereditary effects as reported in the literature, are discussed. (U.K.)

  17. Studies of new light resonances decaying into two hadronic jets produced in association with a radiated jet

    CERN Document Server

    Li, Zhiying

    This report presents combinatorics studies in the search for a resonance of below 800 GeV which decay product is a pair of hadronic jets from quarks. The resonance, predicted as a dark matter mediator, has couplings to dark matter particles as well as quarks and gluons. The resonance is created in association with a radiated object that can be either a photon or a jet. In the case of the radiation being a jet, the dijet from the resonance and the radiated jet cannot be distinguished. Choosing the wrong dijet to reconstruct the resonance decreases the sensitivity of the search. The study focuses on studies that help improve the search sensitivity. The signal samples used in this thesis are generated with Monte Carlo simulation and passed through the ATLAS detector simulation. Firstly, in an attempt to identify the jet from radiation, samples where a jet is radiated and a photon is radiated are compared. However, due to the differences in the sample generations, this attempt does not lead to a successful identi...

  18. Changes in mitochondrial functioning with electromagnetic radiation of ultra high frequency as revealed by electron paramagnetic resonance methods.

    Science.gov (United States)

    Burlaka, Anatoly; Selyuk, Marina; Gafurov, Marat; Lukin, Sergei; Potaskalova, Viktoria; Sidorik, Evgeny

    2014-05-01

    To study the effects of electromagnetic radiation (EMR) of ultra high frequency (UHF) in the doses equivalent to the maximal permitted energy load for the staffs of the radar stations on the biochemical processes that occur in the cell organelles. Liver, cardiac and aorta tissues from the male rats exposed to non-thermal UHF EMR in pulsed and continuous modes were studied during 28 days after the irradiation by the electron paramagnetic resonance (EPR) methods including a spin trapping of superoxide radicals. The qualitative and quantitative disturbances in electron transport chain (ETC) of mitochondria are registered. A formation of the iron-nitrosyl complexes of nitric oxide (NO) radicals with the iron-sulphide (FeS) proteins, the decreased activity of FeS-protein N2 of NADH-ubiquinone oxidoreductase complex and flavo-ubisemiquinone growth combined with the increased rates of superoxide production are obtained. (i) Abnormalities in the mitochondrial ETC of liver and aorta cells are more pronounced for animals radiated in a pulsed mode; (ii) the alterations in the functioning of the mitochondrial ETC cause increase of superoxide radicals generation rate in all samples, formation of cellular hypoxia, and intensification of the oxide-initiated metabolic changes; and (iii) electron paramagnetic resonance methods could be used to track the qualitative and quantitative changes in the mitochondrial ETC caused by the UHF EMR.

  19. Long term effects of radiation in man

    International Nuclear Information System (INIS)

    Tso Chih Ping; Idris Besar

    1984-01-01

    An overview of the long term effects of radiation in man is presented, categorizing into somatic effects, genetic effects and teratogenic effects, and including an indication of the problems that arise in their determination. (author)

  20. Characterization of resonances using finite size effects

    International Nuclear Information System (INIS)

    Pozsgay, B.; Takacs, G.

    2006-01-01

    We develop methods to extract resonance widths from finite volume spectra of (1+1)-dimensional quantum field theories. Our two methods are based on Luscher's description of finite size corrections, and are dubbed the Breit-Wigner and the improved ''mini-Hamiltonian'' method, respectively. We establish a consistent framework for the finite volume description of sufficiently narrow resonances that takes into account the finite size corrections and mass shifts properly. Using predictions from form factor perturbation theory, we test the two methods against finite size data from truncated conformal space approach, and find excellent agreement which confirms both the theoretical framework and the numerical validity of the methods. Although our investigation is carried out in 1+1 dimensions, the extension to physical 3+1 space-time dimensions appears straightforward, given sufficiently accurate finite volume spectra

  1. The effects of 3:1 resonances in stellar pulsations

    International Nuclear Information System (INIS)

    Moskalik, P.; Buchler, J.R.

    1989-01-01

    The effects of a 3:1 resonance are studied and compared to those of a 2:1 resonance. When the growth rate of the higher frequency mode is negative it is shown that a 3:1 resonance affects the pulsation in a very similar fashion to a 2:1 resonance. In fact, it may be very difficult to discriminate in observational data between these two types of coupling. On the other hand, when the higher frequency mode is linearly unstable a 3:1 resonance, contrary to a 2:1 case, is unable to saturate the instability in the absence of nonresonant coupling terms. Astrophysical applications are discussed. 19 refs

  2. Fractional Boltzmann equation for multiple scattering of resonance radiation in low-temperature plasma

    Energy Technology Data Exchange (ETDEWEB)

    Uchaikin, V V; Sibatov, R T, E-mail: vuchaikin@gmail.com, E-mail: ren_sib@bk.ru [Ulyanovsk State University, 432000, 42 Leo Tolstoy str., Ulyanovsk (Russian Federation)

    2011-04-08

    The fractional Boltzmann equation for resonance radiation transport in plasma is proposed. We start with the standard Boltzmann equation; averaging over photon frequencies leads to the appearance of a fractional derivative. This fact is in accordance with the conception of latent variables leading to hereditary and non-local dynamics (in particular, fractional dynamics). The presence of a fractional material derivative in the equation is concordant with heavy tailed distribution of photon path lengths and with spatiotemporal coupling peculiar to the process. We discuss some methods of solving the obtained equation and demonstrate numerical results in some simple cases.

  3. Fractional Boltzmann equation for multiple scattering of resonance radiation in low-temperature plasma

    International Nuclear Information System (INIS)

    Uchaikin, V V; Sibatov, R T

    2011-01-01

    The fractional Boltzmann equation for resonance radiation transport in plasma is proposed. We start with the standard Boltzmann equation; averaging over photon frequencies leads to the appearance of a fractional derivative. This fact is in accordance with the conception of latent variables leading to hereditary and non-local dynamics (in particular, fractional dynamics). The presence of a fractional material derivative in the equation is concordant with heavy tailed distribution of photon path lengths and with spatiotemporal coupling peculiar to the process. We discuss some methods of solving the obtained equation and demonstrate numerical results in some simple cases.

  4. Radiative open charm decay of the Y(3940), Z(3930), X(4160) resonances

    International Nuclear Information System (INIS)

    Liang, W.H.; Molina, R.; Oset, E.

    2010-01-01

    We determine the radiative decay amplitudes for the decay into D * and anti Dγ, or D * s and anti D s γ of some of the charmonium-like states classified as X, Y, Z resonances, plus some other hidden charm states which are dynamically generated from the interaction of vector mesons with charm. The mass distributions as a function of the anti Dγ or anti D s γ invariant mass show a peculiar behavior as a consequence of the D * anti D * nature of these states. The experimental search of these magnitudes can shed light on the nature of these states. (orig.)

  5. Non controlled effect of ionizing radiations : involvement for radiation protection

    International Nuclear Information System (INIS)

    Little, J. B.

    2005-01-01

    It is widely accepted that damage to DNA is the critical event on irradiated cells, and that double strand breaks are the primary DNA lesions responsible for the biological effects of ionizing radiation. This has lead to the long standing paradigm that these effects, be they cytotoxicity, mutagenesis or malignant transformation, occur in irradiated cells as a consequences of the DNA damage they incur. Evidence has been accumulating over the past decade, however, to indicate that radiation may induce effects that ar not targeted to the irradiated cells itself. Two non-targeted effects will be described in this review. The first, radiation-induced genomic instability, is a phenomenon whereby signals are transmitted to the progeny of the irradiated cell over many generations, leading to the occurrence of genetic effects such as mutations and chromosomal aberrations arising in the distant descendants of the irradiated cell. Second, the bystander effect, is a phenomenon whereby irradiated cells transmit damage signals to non-irradiated cells in a mixed population, leading to genetic effects arising in these bystander cells that received no radiation exposure. the model system described in this review involves dense monolayer cultures exposed to very low fluences of alpha particles. The potential implications of these two phenomena for the analysis of the risk to the human population of exposure to low levels of ionising radiation is discussed. (Author) 111 refs

  6. Resonance Spectrum Characteristics of Effective Electromechanical Coupling Coefficient of High-Overtone Bulk Acoustic Resonator

    Directory of Open Access Journals (Sweden)

    Jian Li

    2016-09-01

    Full Text Available A high-overtone bulk acoustic resonator (HBAR consisting of a piezoelectric film with two electrodes on a substrate exhibits a high quality factor (Q and multi-mode resonance spectrum. By analyzing the influences of each layer’s material and structure (thickness parameters on the effective electromechanical coupling coefficient (Keff2, the resonance spectrum characteristics of Keff2 have been investigated systematically, and the optimal design of HBAR has been provided. Besides, a device, corresponding to one of the theoretical cases studied, is fabricated and evaluated. The experimental results are basically consistent with the theoretical results. Finally, the effects of Keff2 on the function of the crystal oscillators constructed with HBARs are proposed. The crystal oscillators can operate in more modes and have a larger frequency hopping bandwidth by using the HBARs with a larger Keff2·Q.

  7. Herpin effective media resonant underlayers and resonant overlayer designs for ultra-high NA interference lithography.

    Science.gov (United States)

    Bourke, Levi; Blaikie, Richard J

    2017-12-01

    Dielectric waveguide resonant underlayers are employed in ultra-high NA interference photolithography to effectively double the depth of field. Generally a single high refractive index waveguiding layer is employed. Here multilayer Herpin effective medium methods are explored to develop equivalent multilayer waveguiding layers. Herpin equivalent resonant underlayers are shown to be suitable replacements provided at least one layer within the Herpin trilayer supports propagating fields. In addition, a method of increasing the intensity incident upon the photoresist using resonant overlayers is also developed. This method is shown to greatly enhance the intensity within the photoresist making the use of thicker, safer, non-absorbing, low refractive index matching liquids potentially suitable for large-scale applications.

  8. Radiation effects on materials in high-radiation environments

    International Nuclear Information System (INIS)

    Weber, W.J.; Mansur, L.K.; Clinard, F.W. Jr.; Parkin, D.M.

    1991-01-01

    A workshop on Radiation Effects on Materials in High-Radiation Environments was held in Salt Lake City, Utah (USA) from August 13 to 15, 1990 under the auspices of the Division of Materials Sciences, Office of Basic Energy Sciences, US Department of Energy. The workshop focused on ceramics, alloys, and intermetallics and covered research needs and capabilities, recent experimental data, theory, and computer simulations. It was concluded that there is clearly a continuing scientific and technological need for fundamental knowledge on the underlying causes of radiation-induced property changes in materials. Furthermore, the success of many current and emerging nuclear-related technologies critically depend on renewed support for basic radiation-effects research, irradiation facilities, and training of scientists. The highlights of the workshop are reviewed and specific recommendations are made regarding research needs. (orig.)

  9. Graphene Field Effect Transistor for Radiation Detection

    Science.gov (United States)

    Li, Mary J. (Inventor); Chen, Zhihong (Inventor)

    2016-01-01

    The present invention relates to a graphene field effect transistor-based radiation sensor for use in a variety of radiation detection applications, including manned spaceflight missions. The sensing mechanism of the radiation sensor is based on the high sensitivity of graphene in the local change of electric field that can result from the interaction of ionizing radiation with a gated undoped silicon absorber serving as the supporting substrate in the graphene field effect transistor. The radiation sensor has low power and high sensitivity, a flexible structure, and a wide temperature range, and can be used in a variety of applications, particularly in space missions for human exploration.

  10. Resonance-enhanced two-photon ionization of ions by Lyman alpha radiation in gaseous nebulae.

    Science.gov (United States)

    Johansson, S; Letokhov, V

    2001-01-26

    One of the mysteries of nebulae in the vicinity of bright stars is the appearance of bright emission spectral lines of ions, which imply fairly high excitation temperatures. We suggest that an ion formation mechanism, based on resonance-enhanced two-photon ionization (RETPI) by intense H Lyman alpha radiation (wavelength of 1215 angstroms) trapped inside optically thick nebulae, can produce these spectral lines. The rate of such an ionization process is high enough for rarefied gaseous media where the recombination rate of the ions formed can be 10(-6) to 10(-8) per second for an electron density of 10(3) to 10(5) per cubic centimeter in the nebula. Under such conditions, the photo-ions formed may subsequently undergo further RETPI, catalyzed by intense He i and He ii radiation, which also gets enhanced in optically thick nebulae that contain enough helium.

  11. Nuclear resonant scattering of synchrotron radiation: Applications in magnetism of layered structures

    International Nuclear Information System (INIS)

    Schlage, Kai; Röhlsberger, Ralf

    2013-01-01

    Highlights: •Depth-resolved determination of magnetic spin structures. •Isotopic probe layers allow for probing selected depths in the sample. •High sensitivity to magnetic domain patterns via diffuse scattering. -- Abstract: Nuclear resonant scattering of synchrotron radiation has become an established tool within condensed-matter research. Synchrotron radiation with its outstanding brilliance, transverse coherence and polarization has opened this field for many unique studies, for fundamental research in the field of light-matter interaction as well as for materials science. This applies in particular for the electronic and magnetic structure of very small sample volumes like micro- and nano-structures and samples under extreme conditions of temperature and pressure. This article is devoted to the application of the technique to nanomagnetic systems such as thin films and multilayers. After a basic introduction into the method, a number of our experiments are presented to illustrate how magnetic spin structures within such layer systems can be revealed

  12. Retrospective radiation dosimetry using electron paramagnetic resonance in canine dental enamel

    International Nuclear Information System (INIS)

    Khan, Rao F.H.; Pekar, J.; Rink, W.J.; Boreham, D.R.

    2005-01-01

    Electron paramagnetic resonance (EPR) biodosimetry of human tooth enamel has been widely used for measuring radiation doses in various scenarios. We have now developed EPR dosimetry in tooth enamel extracted from canines. Molars and incisors from canines were cleaned by processing in supersaturated aqueous potassium hydroxide solution. The dosimetric signal in canine tooth enamel was found to increase linearly as a function of laboratory added dose from 0.44±0.02 to 4.42±0.22 Gy. The gamma radiation sensitivity of the canine molar enamel was found to be comparable to that of human tooth enamel. The dosimetric signal in canine enamel has been found to be stable up to at least 6 weeks after in vitro irradiation. A dosimetric signal variation of 10-25% was observed for canines ranging from in age 3 years to 16 year old

  13. Radiation Characteristics Enhancement of Dielectric Resonator Antenna Using Solid/Discrete Dielectric Lenses

    Directory of Open Access Journals (Sweden)

    H. A. E. Malhat

    2015-02-01

    Full Text Available The radiation characteristics of the dielectric resonator antennas (DRA is enhanced using different types of solid and discrete dielectric lenses. One of these approaches is by loading the DRA with planar superstrate, spherical lens, or by discrete lens (transmitarray. The dimensions and dielectric constant of each lens are optimized to maximize the gain of the DRA. A comparison between the radiations characteristics of the DRA loaded with different lenses are introduced. The design of the dielectric transmitarray depends on optimizing the heights of the dielectric material of the unit cell. The optimized transmitarray achieves 7 dBi extra gain over the single DRA with preserving the circular polarization. The proposed antenna is suitable for various applications that need high gain and focused antenna beam.

  14. Untargeted effects of ionizing radiation: Implications for radiation pathology

    International Nuclear Information System (INIS)

    Wright, Eric G; Coates, Philip J

    2006-01-01

    The dogma that genetic alterations are restricted to directly irradiated cells has been challenged by observations in which effects of ionizing radiation, characteristically associated with the consequences of energy deposition in the cell nucleus, arise in non-irradiated cells. These, so called, untargeted effects are demonstrated in cells that have received damaging signals produced by irradiated cells (radiation-induced bystander effects) or that are the descendants of irradiated cells (radiation-induced genomic instability). Radiation-induced genomic instability is characterized by a number of delayed adverse responses including chromosomal abnormalities, gene mutations and cell death. Similar effects, as well as responses that may be regarded as protective, have been attributed to bystander mechanisms. Whilst the majority of studies to date have used in vitro systems, some adverse non-targeted effects have been demonstrated in vivo. However, at least for haemopoietic tissues, radiation-induced genomic instability in vivo may not necessarily be a reflection of genomically unstable cells. Rather the damage may reflect responses to ongoing production of damaging signals; i.e. bystander responses, but not in the sense used to describe the rapidly induced effects resulting from direct interaction of irradiated and non-irradiated cells. The findings are consistent with a delayed and long-lived tissue reaction to radiation injury characteristic of an inflammatory response with the potential for persisting bystander-mediated damage. An important implication of the findings is that contrary to conventional radiobiological dogma and interpretation of epidemiologically-based risk estimates, ionizing radiation may contribute to malignancy and particularly childhood leukaemia by promoting initiated cells rather than being the initiating agent. Untargeted mechanisms may also contribute to other pathological consequences

  15. A-bomb radiation effects digest

    International Nuclear Information System (INIS)

    Shigematsu, Itsuzo; Akiyama, Mitoshi; Sasaki, Hideo; Ito, Chikako; Kamada, Nanao.

    1993-01-01

    This publication is the digest of the book 'Genbaku Hoshasen no Jintai Eikyo (Effects of A-bomb Radiation on the Human Body)' (365p.), published in Japanese by Hiroshima International Council for Medical Care of the Radiation-Exposed. Following a brief description on the damage of the atomic bomb, the subjects of malignant tumors, endocrine and metabolic deseases, ocular lesions, dermatologic effects, prenatal exposure, chromosoal aberrations, mutations, sensitivity to radiation, immune function, genetic effects and other effects of radiation are summarized. (J.P.N.)

  16. Long-term effects of ionizing radiation

    International Nuclear Information System (INIS)

    Kaul, Alexander; Burkart, Werner; Grosche, Bernd; Jung, Thomas; Martignoni, Klaus; Stephan, Guenther

    1997-01-01

    This paper approaches the long-term effects of ionizing radiation considering the common thought that killing of cells is the basis for deterministic effects and that the subtle changes in genetic information are important in the development of radiation-induced cancer, or genetic effects if these changes are induced in germ cells

  17. Interventional Radiation Oncology (IRO): Transition of a magnetic resonance simulator to a brachytherapy suite.

    Science.gov (United States)

    Anderson, Roberta; Armour, Elwood; Beeckler, Courtney; Briner, Valerie; Choflet, Amanda; Cox, Andrea; Fader, Amanda N; Hannah, Marie N; Hobbs, Robert; Huang, Ellen; Kiely, Marilyn; Lee, Junghoon; Morcos, Marc; McMillan, Paige E; Miller, Dave; Ng, Sook Kien; Prasad, Rashmi; Souranis, Annette; Thomsen, Robert; DeWeese, Theodore L; Viswanathan, Akila N

    2018-03-13

    As a core component of a new gynecologic cancer radiation program, we envisioned, structured, and implemented a novel Interventional Radiation Oncology (IRO) unit and magnetic resonance (MR)-brachytherapy environment in an existing MR simulator. We describe the external and internal processes required over a 6-8 month time frame to develop a clinical and research program for gynecologic brachytherapy and to successfully convert an MR simulator into an IRO unit. Support of the institution and department resulted in conversion of an MR simulator to a procedural suite. Development of the MR gynecologic brachytherapy program required novel equipment, staffing, infrastructural development, and cooperative team development with anesthetists, nurses, therapists, physicists, and physicians to ensure a safe and functional environment. Creation of a separate IRO unit permitted a novel billing structure. The creation of an MR-brachytherapy environment in an MR simulator is feasible. Developing infrastructure includes several collaborative elements. Unique to the field of radiation oncology, formalizing the space as an Interventional Radiation Oncology unit permits a sustainable financial structure. Copyright © 2018 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  18. Radiation hazards and their effects

    International Nuclear Information System (INIS)

    Lunu, Shyam; Kumar, Hemant; Joshi, Pankaj Kumar; Songara, Venkteshwer

    2012-01-01

    Radiation can be classified into ionizing radiation and non-ionizing radiation, based on whether it is capable of ionizing atoms and breaking chemical bonds. Ultraviolet and higher frequency such as X-rays, gamma rays are ionizing. These pose their own special hazards. Non ionizing radiation is associated with two major potential hazards. i.e. electrical and biological. Additionally includes electric current caused by radiation can generate sparks and create a fire or explosive hazards. Strong radiation can induce current capable of delivering an electric shock. Extremely high power electromagnetic radiation can cause electric currents strong enough to create sparks when an induced voltage exceeds the breakdown voltage of surrounding mediums. A 2009 study at the University of Basal in Switzerland found that intermitted exposure of human cells to a 50 Hz electromagnetic field at a flux density of 10 Gy induced a slight but significant increase of DNA fragmentation in the comet assay. Mobile phones radiation and health concerns have been raised, especially following the enormous increase in the use of wireless mobile telephony throughout the world. Mobile phones use electromagnetic radiation in the microwaves range and some believes this may be harmful to human health. (author)

  19. Temperature effects on radiation damage in plastic detectors

    International Nuclear Information System (INIS)

    Mendoza A, D.

    1996-01-01

    The objective of present work was to study the temperature effect on radiation damage registration in the structure of a Solid State Nuclear Track Detector of the type CR-39. In order to study the radiation damage as a function of irradiation temperature, sheets of CR-39 detectors were irradiated with electron beams, simulating the interaction of positive ions. CR-39 detectors were maintained at a constant temperature from room temperature up to 373 K during irradiation. Two techniques were used from analyzing changes in the detector structure: Electronic Paramagnetic Resonance (EPR) and Infrared Spectroscopy (IR). It was found by EPR analysis that the amount of free radicals decrease as irradiation temperature increases. The IR spectrums show yield of new functional group identified as an hydroxyl group (OH). A proposed model of interaction of radiation with CR-39 detectors is discussed. (Author)

  20. Ionizing Radiation Detectors Based on Ge-Doped Optical Fibers Inserted in Resonant Cavities

    Directory of Open Access Journals (Sweden)

    Saverio Avino

    2015-02-01

    Full Text Available The measurement of ionizing radiation (IR is a crucial issue in different areas of interest, from environmental safety and industrial monitoring to aerospace and medicine. Optical fiber sensors have recently proven good candidates as radiation dosimeters. Here we investigate the effect of IR on germanosilicate optical fibers. A piece of Ge-doped fiber enclosed between two fiber Bragg gratings (FBGs is irradiated with gamma radiation generated by a 6 MV medical linear accelerator. With respect to other FBG-based IR dosimeters, here the sensor is only the bare fiber without any special internal structure. A near infrared laser is frequency locked to the cavity modes for high resolution measurement of radiation induced effects on the fiber optical parameters. In particular, we observe a variation of the fiber thermo-optic response with the radiation dose delivered, as expected from the interaction with Ge defect centers, and demonstrate a detection limit of 360 mGy. This method can have an impact in those contexts where low radiation doses have to be measured both in small volumes or over large areas, such as radiation therapy and radiation protection, while bare optical fibers are cheap and disposable.

  1. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...

  2. Isotopic imaging via nuclear resonance fluorescence with laser-based Thomson radiation

    Science.gov (United States)

    Barty, Christopher P. J. [Hayward, CA; Hartemann, Frederic V [San Ramon, CA; McNabb, Dennis P [Alameda, CA; Pruet, Jason A [Brentwood, CA

    2009-07-21

    The present invention utilizes novel laser-based, high-brightness, high-spatial-resolution, pencil-beam sources of spectrally pure hard x-ray and gamma-ray radiation to induce resonant scattering in specific nuclei, i.e., nuclear resonance fluorescence. By monitoring such fluorescence as a function of beam position, it is possible to image in either two dimensions or three dimensions, the position and concentration of individual isotopes in a specific material configuration. Such methods of the present invention material identification, spatial resolution of material location and ability to locate and identify materials shielded by other materials, such as, for example, behind a lead wall. The foundation of the present invention is the generation of quasimonochromatic high-energy x-ray (100's of keV) and gamma-ray (greater than about 1 MeV) radiation via the collision of intense laser pulses from relativistic electrons. Such a process as utilized herein, i.e., Thomson scattering or inverse-Compton scattering, produces beams having diameters from about 1 micron to about 100 microns of high-energy photons with a bandwidth of .DELTA.E/E of approximately 10E.sup.-3.

  3. Anomalous resonance-radiation energy-transfer rate in a scattering dispersive medium

    International Nuclear Information System (INIS)

    Shekhtman, V.L.

    1992-01-01

    This paper describes a generalization of the concept of group velocity as an energy-transfer rate in a dispersive medium with complex refractive index when the polaritons, which are energy carriers, undergo scattering, in contrast to the classical concept of the group velocity of free polaritons (i.e., without scattering in the medium). The concept of delay time from quantum multichannel-scattering, theory is used as the fundamental concept. Based on Maxwell's equations and the new mathematical Φ-function method, a consistent conceptual definition of group velocity in terms of the ratio of the coherent-energy flux density to the coherent-energy density is obtained for the first time, and a critical analysis of the earlier (Brillouin) understanding of energy-transfer rate is given in the light of radiation-trapping theory and the quantum theory of resonance scattering. The role of generalized group velocity is examined for the interpretation of the phenomenon of multiple resonance scattering, or radiation diffusion. The question of causality for the given problem is touched upon; a new relationship is obtained, called the microcausality condition, which limits the anomalous values of group velocity by way of the indeterminacy principle and the relativistic causality principle for macroscopic time intervals directly measurable in experiment, whereby attention is focused on the connection of the given microcausality condition and the well-known Wigner inequality for the time delay of spherical waves. 22 refs

  4. ECR [electron cyclotron resonance] discharges maintained by radiation in the millimeter wavelength range

    International Nuclear Information System (INIS)

    Bykov, Yu.V.; Golubev, S.V.; Eremeev, A.G.; Zorin, V.G.

    1990-01-01

    It is well known that plasmas formed by microwave breakdown of gases under electron cyclotron resonance (ECR) conditions can serve as an efficient source for ion beams. The major disadvantage of this type of source is relatively low ion beam currents which generally do not exceed 1 A (for an electron density of ∼10 12 cm -3 in the discharge). Raising the current density in the ion beams requires a higher plasma density, which can be obtained by using higher frequencies. Thus, a study has recently been made of the parameters of the plasma formed by ECR breakdown in a linear confinement system employing pulsed radiation at a frequency of 60 GHz. The maximum electron densities obtained in the experiment were 2·10 13 cm -3 at a gas pressure of 3·10 -4 torr. In this paper the authors describe some experiments on the creation of plasmas by means of quasi-cw electromagnetic radiation at a frequency of 100 GHz under electron cyclotron resonance conditions

  5. High energy radiation precursors to the collapse of black holes binaries based on resonating plasma modes

    Science.gov (United States)

    Coppi, B.

    2018-05-01

    The presence of well organized plasma structures around binary systems of collapsed objects [1,2] (black holes and neutron stars) is proposed in which processes can develop [3] leading to high energy electromagnetic radiation emission immediately before the binary collapse. The formulated theoretical model supporting this argument shows that resonating plasma collective modes can be excited in the relevant magnetized plasma structure. Accordingly, the collapse of the binary approaches, with the loss of angular momentum by emission of gravitational waves [2], the resonance conditions with vertically standing plasma density and magnetic field oscillations are met. Then, secondary plasma modes propagating along the magnetic field are envisioned to be sustained with mode-particle interactions producing the particle populations responsible for the observable electromagnetic radiation emission. Weak evidence for a precursor to the binary collapse reported in Ref. [2], has been offered by the Agile X-γ-ray observatory [4] while the August 17 (2017) event, identified first by the LIGO-Virgo detection of gravitational waves and featuring the inferred collapse of a neutron star binary, improves the evidence of such a precursor. A new set of experimental observations is needed to reassess the presented theory.

  6. Acoustic radiation force induced resonance elastography of coagulating blood: theoretical viscoelasticity modeling and ex vivo experimentation

    Science.gov (United States)

    Bhatt, Manish; Montagnon, Emmanuel; Destrempes, François; Chayer, Boris; Kazemirad, Siavash; Cloutier, Guy

    2018-03-01

    Deep vein thrombosis is a common vascular disease that can lead to pulmonary embolism and death. The early diagnosis and clot age staging are important parameters for reliable therapy planning. This article presents an acoustic radiation force induced resonance elastography method for the viscoelastic characterization of clotting blood. The physical concept of this method relies on the mechanical resonance of the blood clot occurring at specific frequencies. Resonances are induced by focusing ultrasound beams inside the sample under investigation. Coupled to an analytical model of wave scattering, the ability of the proposed method to characterize the viscoelasticity of a mimicked venous thrombosis in the acute phase is demonstrated. Experiments with a gelatin-agar inclusion sample of known viscoelasticity are performed for validation and establishment of the proof of concept. In addition, an inversion method is applied in vitro for the kinetic monitoring of the blood coagulation process of six human blood samples obtained from two volunteers. The computed elasticity and viscosity values of blood samples at the end of the 90 min kinetics were estimated at 411  ±  71 Pa and 0.25  ±  0.03 Pa · s for volunteer #1, and 387  ±  35 Pa and 0.23  ±  0.02 Pa · s for volunteer #2, respectively. The proposed method allowed reproducible time-varying thrombus viscoelastic measurements from samples having physiological dimensions.

  7. Observation and resonant x-ray optical interpretation of multi-atom resonant photoemission effects in O 1s emission from NiO

    International Nuclear Information System (INIS)

    Mannella, N.; Yang, S.-H.; Mun, B.S.; Garcia de Abajo, F.J.; Kay, A.W.; Sell, B.C.; Watanabe, M.; Ohldag, H.; Arenholz, E.; Young, A.T.; Hussain, Z.; Van Hove, M.A.; Fadley, C.S.

    2006-01-01

    We present experimental and theoretical results for the variation of the O 1s intensity from a NiO(001) surface as the excitation energy is varied through the Ni 2p1/2,3/2 absorption resonances, and as the incidence angle of the radiation is varied from grazing to larger values. For grazing incidence, a strong multi-atom resonant photoemission(MARPE) effect is seen on the O 1s intensity as the Ni 2p resonances are crossed, but its magnitude decreases rapidly as the incidence angle is increased. Resonant x-ray optical (RXRO) calculations are found to predict these effects very well, although the experimental effects are found to decrease at higher incidence angles faster than those in theory. The potential influence of photoelectron diffraction effects on such measurements are also considered, including experimental data with azimuthal-angle variation and corresponding multiple-scattering-diffraction calculations, but we conclude that they do not vary beyond what is expected on the basis of the change in photoelectron kinetic energy. Varying from linear polarization to circular polarization is found to enhance these effects in NiO considerably, although the reasons are not clear. We also discuss the relationship of these measurements to other related interatomic resonance experiments and theoretical developments, and make some suggestions for future studies in this area

  8. Some characteristics and effects of natural radiation

    International Nuclear Information System (INIS)

    Mc Laughlin, J.P.

    2015-01-01

    Since life first appeared on the Earth, it has, in all its subsequent evolved forms including human, been exposed to natural radiation in the environment both from terrestrial and extra-terrestrial sources. Being an environmental mutagen, ionising natural radiation may have played a role of some significance in the evolution of early life forms on Earth. It has been estimated by United Nations Scientific Committee on the Effects of Atomic Radiation that at the present time, exposure to natural radiation globally results in an annual average individual effective dose of about 2.4 mSv. This represents about 80 % of the total dose from all sources. The three most important components of natural radiation exposure are cosmic radiation, terrestrial radioactivity and indoor radon. Each of these components exhibits both geographical and temporal variabilities with indoor radon exposure being the most variable and also the largest contributor to dose for most people. In this account, an overview is given of the characteristics of the main components of the natural radiation environment and some of their effects on humans. In the case of cosmic radiation, these range from radiation doses to aircrew and astronauts to the controversial topic of its possible effect on climate change. In the case of terrestrial natural radiation, accounts are given of a number of human exposure scenarios. (author)

  9. Nonlinear Resonance Islands and Modulational Effects in a Proton Synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Satogata, Todd Jeffrey [Northwestern Univ., Evanston, IL (United States)

    1993-01-01

    We examine both one-dimensional and two-dimensional nonlinear resonance islands created in the transverse phase space of a proton synchrotron by nonlinear magnets. We also examine application of the theoretical framework constructed to the phenomenon of modulational diffusion in a collider model of the Fermilab Tevatron. For the one-dimensional resonance island system, we examine the effects of two types of modulational perturbations on the stability of these resonance islands: tune modulation and beta function modulation. Hamiltonian models are presented which predict stability boundaries that depend on only three paramders: the strength and frequency of the modulation and the frequency of small oscillations inside the resonance island. These. models are compared to particle tracking with excellent agreement. The tune modulation model is also successfully tested in experiment, where frequency domain analysis coupled with tune modulation is demonstrated to be useful in measuring the strength of a nonlinear resonance. Nonlinear resonance islands are also examined in two transverse dimensions in the presence of coupling and linearly independent crossing resonances. We present a first-order Hamiltonian model which predicts fixed point locations, but does not reproduce small oscillation frequencies seen in tracking; therefore in this circumstance such a model is inadequate. Particle tracking is presented which shows evidence of two-dimensional persistent signals, and we make suggestions on methods for observing such signals in future experiment.

  10. Radiation-induced changes in human brain metabolites as studied by {sup 1}H nuclear magnetic resonance spectroscopy in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Usenius, Taina; Usenius, Jussi-Pekka; Tenhunen, Mikko; Vainio, Pauli; Johansson, Risto; Soimakallio, Seppo; Kauppinen, Risto

    1995-10-15

    Purpose: External radiation therapy for brain tumors exposes healthy areas of brain to considerable doses of radiation. This may cause cognitive and psychological impairment, which indicate neuronal dysfunction. {sup 1}H-magnetic resonance spectroscopy (MRS) was used to study brain metabolites in the adjacent regions 0.5-13 years after exposure to therapeutic irradiation. Methods and Materials: Eight patients with irradiated brain tumors were examined by means of in vivo{sup 1}H-MRS using a point-resolved spectroscopy (PRESS) sequence with echo times of 60 or 270 ms. The metabolites were quantified by using brain water concentration as internal reference. The volume of interest (VOI) was positioned in irradiated brain areas excluding, however, scar and recurrent tumor. The respective radiation doses were measured based on radiation therapy plans, simulator films, and localization MR images. Results: The concentration of the neuron-specific metabolite N-acetyl-l-aspartate (NAA) was 13.2 {+-} 1.4 mmol/l in controls, whereas it was reduced in the brains of treated patients to 8.6 {+-} 0.9 mmol/l (total radiation dose 59-62 Gy). Concentrations of creatine and choline-containing compounds were unchanged. The T2 of water was longer in irradiated than in unexposed brain areas. Conclusion: Therapeutic brain irradiation causes neuronal damage, which is reflected by reduction of N-acetyl-l-aspartate (NAA) concentrations. {sup 1}H-MRS could serve clinically as a means of evaluating adverse effects in the central nervous system, enabling intervention and rehabilitation.

  11. Radiation-induced changes in human brain metabolites as studied by 1H nuclear magnetic resonance spectroscopy in vivo

    International Nuclear Information System (INIS)

    Usenius, Taina; Usenius, Jussi-Pekka; Tenhunen, Mikko; Vainio, Pauli; Johansson, Risto; Soimakallio, Seppo; Kauppinen, Risto

    1995-01-01

    Purpose: External radiation therapy for brain tumors exposes healthy areas of brain to considerable doses of radiation. This may cause cognitive and psychological impairment, which indicate neuronal dysfunction. 1 H-magnetic resonance spectroscopy (MRS) was used to study brain metabolites in the adjacent regions 0.5-13 years after exposure to therapeutic irradiation. Methods and Materials: Eight patients with irradiated brain tumors were examined by means of in vivo 1 H-MRS using a point-resolved spectroscopy (PRESS) sequence with echo times of 60 or 270 ms. The metabolites were quantified by using brain water concentration as internal reference. The volume of interest (VOI) was positioned in irradiated brain areas excluding, however, scar and recurrent tumor. The respective radiation doses were measured based on radiation therapy plans, simulator films, and localization MR images. Results: The concentration of the neuron-specific metabolite N-acetyl-l-aspartate (NAA) was 13.2 ± 1.4 mmol/l in controls, whereas it was reduced in the brains of treated patients to 8.6 ± 0.9 mmol/l (total radiation dose 59-62 Gy). Concentrations of creatine and choline-containing compounds were unchanged. The T2 of water was longer in irradiated than in unexposed brain areas. Conclusion: Therapeutic brain irradiation causes neuronal damage, which is reflected by reduction of N-acetyl-l-aspartate (NAA) concentrations. 1 H-MRS could serve clinically as a means of evaluating adverse effects in the central nervous system, enabling intervention and rehabilitation

  12. Numerical study of combustion initiation in a supersonic flow of H2-air mixture by resonance laser radiation

    International Nuclear Information System (INIS)

    Bezgin, L V; Kopchenov, V I; Kuleshov, P S; Titova, N S; Starik, A M

    2012-01-01

    A comparative analysis of the efficiency of approaches based on the exposure of reacting gas to resonance laser radiation to enhance combustion in a supersonic flow of H 2 -air mixture is conducted. The kinetic processes responsible for the intensification of chain reactions in premixed and non-premixed H 2 -air flows upon photodissociation of O 2 molecules by 193.3 nm laser radiation, excitation of these molecules to the singlet sigma state by laser photons with 762.346 nm wavelength and heating the mixture by laser radiation are analysed in a detailed manner. It is shown that both photochemical methods, photodissociation and excitation of O 2 molecules, are much more effective in shortening the ignition delay length than merely heating the mixture. For the premixed flow, the photodissociation of O 2 molecules ensures a slightly higher reduction in the ignition delay than the laser-induced excitation of molecular oxygen to the singlet sigma state. However, in the non-premixed flow the situation is inverted. The analysis shows that both photochemical methods make it possible to raise the efficiency of conversion of reactant chemical energy to thermal energy released during combustion compared with the method of heating the mixtures. (paper)

  13. Large intracranial vessel occlusive vasculopathy after radiation therapy in children: clinical features and usefulness of magnetic resonance imaging

    International Nuclear Information System (INIS)

    Omura, Motoko; Aida, Noriko; Sekido, Kenichi; Kakehi, Masae; Matsubara, Sho

    1997-01-01

    Purpose: To assess the relationship between large intracranial vessel occlusive vasculopathy (vasculopathy) and radiation therapy, and to clarify the clinical efficacy of magnetic resonance (MR) imaging in the diagnosis and screening of the vasculopathy. Methods and Materials: We retrospectively evaluated the medical records and serial MR images for 32 pediatric patients, in whom radiation therapy had been given to fields including the circle of Willis and major cerebral arteries. All children had periodically undergone follow-up neurologic assessment and MR imaging examinations at Kanagawa Children's Medical Center for more than one year after radiation therapy (range 1.3-14 years). Patients who had not remained free of tumor progression up to the time of final evaluation were excluded. Results: Vasculopathy developed in 6 of 32 patients 2-13 years after radiation therapy. Three of them presented with transient ischemic attacks (TIA) and the other three showed infarctions without preceding TIA. Steno-occlusive changes of major cerebral arteries were identified by MR imaging in all six patients, but not obtained in the remaining 26 patients. In the patients with TIA, MR imaging demonstrated steno-occlusive changes at the time of TIA, before irreversible infarction. They have been doing well subsequent to encephaloduraoarteriosyn-angiosis. In the three patients who presented infarction without preceding TIA, MR imaging did not demonstrate the vascular change before the onset of infarction, and two of them developed neurologic deficits. The mean exposure dose for the circle of Willis and major cerebral arteries in these six patients was significantly higher than that in the remaining 26 patients without this sequela (61Gy vs. 50Gy, p < 0.05). The mean age at radiation therapy of the six patients was lower, but the difference was not significant. Conclusion: The incidence of vasculopathy after radiation therapy has a considerable correlation with radiation dose and

  14. Radiation effects in ice: New results

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Fama, M.; Loeffler, M.J.; Raut, U.; Shi, J.

    2008-01-01

    Studies of radiation effects in ice are motivated by intrinsic interest and by applications in astronomy. Here we report on new and recent results on radiation effects induced by energetic ions in ice: amorphization of crystalline ice, compaction of microporous amorphous ice, electrostatic charging and dielectric breakdown and correlated structural/chemical changes in the irradiation of water-ammonia ices

  15. Radiation effects of ion beams on polymers

    International Nuclear Information System (INIS)

    Tagawa, Seiichi

    1993-01-01

    Recent progress in the radiation effects of ion beams on polymers are reviewed briefly. Our recent work on the radiation effects of ion beams on polystyrene thin films on silicon wafers and time resolved emission studies on polymers are described. (orig.)

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

    Science.gov (United States)

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

    2014-01-01

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

  17. Calculation of Resonance Interaction Effects Using a Rational Approximation to the Symmetric Resonance Line Shape Function

    International Nuclear Information System (INIS)

    Haeggblom, H.

    1968-08-01

    The method of calculating the resonance interaction effect by series expansions has been studied. Starting from the assumption that the neutron flux in a homogeneous mixture is inversely proportional to the total cross section, the expression for the flux can be simplified by series expansions. Two types of expansions are investigated and it is shown that only one of them is generally applicable. It is also shown that this expansion gives sufficient accuracy if the approximate resonance line shape function is reasonably representative. An investigation is made of the approximation of the resonance shape function with a Gaussian function which in some cases has been used to calculate the interaction effect. It is shown that this approximation is not sufficiently accurate in all cases which can occur in practice. Then, a rational approximation is introduced which in the first order approximation gives the same order of accuracy as a practically exact shape function. The integrations can be made analytically in the complex plane and the method is therefore very fast compared to purely numerical integrations. The method can be applied both to statistically correlated and uncorrelated resonances

  18. Calculation of Resonance Interaction Effects Using a Rational Approximation to the Symmetric Resonance Line Shape Function

    Energy Technology Data Exchange (ETDEWEB)

    Haeggblom, H

    1968-08-15

    The method of calculating the resonance interaction effect by series expansions has been studied. Starting from the assumption that the neutron flux in a homogeneous mixture is inversely proportional to the total cross section, the expression for the flux can be simplified by series expansions. Two types of expansions are investigated and it is shown that only one of them is generally applicable. It is also shown that this expansion gives sufficient accuracy if the approximate resonance line shape function is reasonably representative. An investigation is made of the approximation of the resonance shape function with a Gaussian function which in some cases has been used to calculate the interaction effect. It is shown that this approximation is not sufficiently accurate in all cases which can occur in practice. Then, a rational approximation is introduced which in the first order approximation gives the same order of accuracy as a practically exact shape function. The integrations can be made analytically in the complex plane and the method is therefore very fast compared to purely numerical integrations. The method can be applied both to statistically correlated and uncorrelated resonances.

  19. Radiobiologic effects at low radiation levels

    International Nuclear Information System (INIS)

    Casarett, G.W.

    1975-01-01

    Data are reviewed on the effects of low radiation doses on mammals. Data from the 1972 report on the Biological Effects of Ionizing Radiation issued by the Advisory Committee of the National Academy of Sciences and National Research Council are discussed. It was concluded that there are certain radiosensitive systems in which low doses of radiation may cause degenerative effects, including gametogenic epithelium, lens of the eye, and developing embryos. Despite extensive investigation of genetic effects, including chromosomal effects, neither the amount of change that will be caused by very low levels of irradiation nor the degree of associated detriment is known

  20. Dynamic contrast-enhanced magnetic resonance imaging of radiation therapy-induced microcirculation changes in rectal cancer

    International Nuclear Information System (INIS)

    Lussanet, Quido G. de; Backes, Walter H.; Griffioen, Arjan W.; Padhani, Anwar R.; Baeten, Coen I.; Baardwijk, Angela van; Lambin, Philippe; Beets, Geerard L.; Engelshoven, Jos van; Beets-Tan, Regina G.H.

    2005-01-01

    Purpose: Dynamic contrast-enhanced T1-weighted magnetic resonance imaging (DCE-MRI) allows noninvasive evaluation of tumor microvasculature characteristics. This study evaluated radiation therapy related microvascular changes in locally advanced rectal cancer by DCE-MRI and histology. Methods and Materials: Dynamic contrast-enhanced-MRI was performed in 17 patients with primary rectal cancer. Seven patients underwent 25 fractions of 1.8 Gy radiation therapy (RT) (long RT) before DCE-MRI and 10 did not. Of these 10, 3 patients underwent five fractions of 5 Gy RT (short RT) in the week before surgery. The RT treated and nontreated groups were compared in terms of endothelial transfer coefficient (K PS , measured by DCE-MRI), microvessel density (MVD) (scored by immunoreactivity to CD31 and CD34), and tumor cell and endothelial cell proliferation (scored by immunoreactivity to Ki67). Results: Tumor K PS was 77% (p = 0.03) lower in the RT-treated group. Histogram analyses showed that RT reduced both magnitude and intratumor heterogeneity of K PS (p = 0.01). MVD was significantly lower (37%, p 0.03) in tumors treated with long RT than in nonirradiated tumors, but this was not the case with short RT. Endothelial cell proliferation was reduced with short RT (81%, p = 0.02) just before surgery, but not with long RT (p > 0.8). Tumor cell proliferation was reduced with both long (57%, p PS values showed significant radiation therapy related reductions in microvessel blood flow in locally advanced rectal cancer. These findings may be useful in evaluating effects of radiation combination therapies (e.g., chemoradiation or RT combined with antiangiogenesis therapy), to account for effects of RT alone

  1. Physics of intense, high energy radiation effects.

    Energy Technology Data Exchange (ETDEWEB)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-02-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic

  2. Physics of intense, high energy radiation effects

    International Nuclear Information System (INIS)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-01-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic calculations, the

  3. Radiation Effects on Polymers - XI

    DEFF Research Database (Denmark)

    Ghanem, N. A.; El-Awady, N. I.; Singer, Klaus Albert Julius

    1979-01-01

    With the aim of improving properties of cellulose acetate membranes for reverse osmosis desalination, grafting was performed using high energy electrons. In this paper, the grafting parameters (radiation dose and method, monomer concentration, solvents, chain transfer agent and redox system...

  4. Radiation effects in polycarbonate capacitors

    Directory of Open Access Journals (Sweden)

    Vujisić Miloš

    2009-01-01

    Full Text Available The aim of this paper is to examine the influence of neutron and gamma irradiation on the dissipation factor and capacitance of capacitors with polycarbonate dielectrics. The operation of capacitors subject to extreme conditions, such as the presence of ionizing radiation fields, is of special concern in military industry and space technology. Results obtained show that the exposure to a mixed neutron and gamma radiation field causes a decrease of capacitance, while the loss tangent remains unchanged.

  5. Biological effects of high LET radiations

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masami [Nagasaki Univ. (Japan). Faculty of Pharmaceutical Sciences

    1997-03-01

    Biological effect of radiation is different by a kind of it greatly. Heavy ions were generally more effective in cell inactivation, chromosome aberration induction, mutation induction and neoplastic cell transformation induction than {gamma}-rays in SHE cells. (author)

  6. Genetic effects of ionizing radiation

    International Nuclear Information System (INIS)

    Myers, D.K.; Childs, J.D.

    1980-01-01

    The genetic material in living organisms is susceptible to damage from a wide variety of causes including radiation exposure. Most of this damage is repaired by the organism; the residual damage and damage which is not correctly repaired can lead to genetic changes such as mutations. In lower organisms, most offspring carry an unaltered copy of the genetic information that was present in the parental organism, most of the genetic changes which do occur are not caused by natural background radiation, and the increase in frequency of genetic changes after irradiation at low-dose rates is directly proportional to total radiation dose. The same principles appear to be valid in mammals and other higher organisms. About 105 out of every 1000 humans born suffer from some genetic or partly-genetic condition requiring medical attention at some time. It has been estimated that approximately 1 person in every 2000 born carry a deleterious genetic mutation that was caused by the continued exposure of many generations of our ancestors to natural background radiation. On the same basis, it is predicted that the incidence of genetic diseases would be increased to 106 per 1000 in the children and grandchildren of radiation workers who were exposed to 1 rem per year commencing at age 18. However, there was no detectable change in the health and fitness of mice whose male ancestors were repeatedly exposed to high radiation doses up to 900 rem per generation. (auth)

  7. Modification of genetic effects of gamma radiation by laser radiation

    International Nuclear Information System (INIS)

    Khotyljova, L.V.; Khokhlova, S.A.; Khokhlov, I.V.

    1988-01-01

    Full text: Mutants obtained by means of ionizing radiation and chemical mutagens often show low viability and productivity that makes their use in plant breeding difficult. Methods reducing the destructive mutagen action on important functions of plant organism and increasing quality and practical value of induced mutants would be interesting. We believe that one method for increasing efficiency of experimental mutagenesis in plants is the application of laser radiation as a modificator of genetic effects of ionizing radiation and chemical mutagens. Combined exposure of wheat seedlings to a gamma radiation dose of 2 kR and to laser radiation with the wave length of 632.8 nm (power density - 20 mVt/cm 2 , exposure - 30 min.) resulted in reducing the chromosomal aberration percentage from 30.5% in the gamma version to 16.3% in the combined treatment version. A radiosensibilizing effect was observed at additional exposure of gamma irradiated wheat seeds to laser light with the wave length of 441.6 nm where chromosomal aberration percentage increased from 22% in the gamma-irradiation version to 31% in the combined treatment version. By laser radiation it is also possible to normalize mitotic cell activity suppressed by gamma irradiation. Additional seedling irradiation with the light of helium-neon laser (632.8 nm) resulted in recovery of mitotic cell activity from 21% to 62% and increasing the average content of DNA per nucleus by 10%. The influence of only laser radiation on plant variability was also studied and it was shown that irradiation of wheat seeds and seedlings with pulsed and continuous laser light of visible spectrum resulted in phenotypically altered forms in M 2 . Their frequencies was dependent upon power density, dose and radiation wave length. Number of altered forms increased in going from long-wave to short-wave spectrum region. In comparing efficiency of different laser types of pulsed and continuous exposure (dose - 180 J/cm 2 ) 2% of altered

  8. Radiation effects on light sources and detectors

    International Nuclear Information System (INIS)

    Barnes, C.E.

    1985-01-01

    The rapidly expanding field of optoelectronics includes a wide variety of both military and non-military applications in which the systems must meet radiation exposure requirements. Herein, we review the work on radiation effects on sources and detectors for such optoelectronic systems. For sources the principal problem is permanent damage-induced light output degradation, while for detectors it is ionizing radiation-induced photocurrents

  9. Effects of ionizing radiation on nitric oxide myoglobin

    International Nuclear Information System (INIS)

    Kamarei, A.R.; Karel, M.

    1983-01-01

    Bovine nitric oxide myoglobin (NOMb) was irradiated with 40-4000 krad of γ-radiation, and the effects on the haem studied using absorption spectroscopy and electron spin resonance (e.s.r.) spectroscopy. The results show the following behaviour: (a) The bright red colour of NOMb changes to brown upon irradiation. This is similar to changes observed in radiation sterilized, nitrite-containing meats. (b) NOMb becomes progressively denitrosylated, with met-myoglobin (metMb) as the immediate product. (c) Upon increasing doses of radiation (up to 800 krad) at O 0 C parallel to NOMb denitrosylation, metMb is gradually converted, by water radiolytic products, to other products, believed to be ferromyoglobin and ferrimyoglobin peroxide. A minor quantity of 'choleglobin-type' pigments may also be formed at the highest doses. (d) Freezing of NOMb has a substantial protective effect against radiation. (e) Native bovine NOMb behaves as a pentaco-ordinate (hfs of 3 peaks with equal intensity); the bond between iron and Nsub(epsilon) is thus dramatically stretched and weakened. (f) Using a thermal energy analyser, no NO could be detected over irradiated NOMb solution, indicating rapid reaction of NO liberated from NOMb by radiation, with radiolytic products of water. (author)

  10. Bystander Effects of Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B. [Harvard T.H. Chan School of Public Health, Boston, MA (United States). Dept. of Genetics and Complex Diseases

    2017-01-17

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low-dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  11. Bystander Effects of Ionizing Radiation

    International Nuclear Information System (INIS)

    Little, John B.

    2017-01-01

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low-dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  12. Electron-spin-resonance study of radiation-induced paramagnetic defects in oxides grown on (100) silicon substrates

    International Nuclear Information System (INIS)

    Kim, Y.Y.; Lenahan, P.M.

    1988-01-01

    We have used electron-spin resonance to investigate radiation-induced point defects in Si/SiO 2 structures with (100) silicon substrates. We find that the radiation-induced point defects are quite similar to defects generated in Si/SiO 2 structures grown on (111) silicon substrates. In both cases, an oxygen-deficient silicon center, the E' defect, appears to be responsible for trapped positive charge. In both cases trivalent silicon (P/sub b/ centers) defects are primarily responsible for radiation-induced interface states. In earlier electron-spin-resonance studies of unirradiated (100) substrate capacitors two types of P/sub b/ centers were observed; in oxides prepared in three different ways only one of these centers, the P/sub b/ 0 defect, is generated in large numbers by ionizing radiation

  13. General trend and local variations of neutron resonance cascade gamma-decay radiative strength functions

    International Nuclear Information System (INIS)

    Sukhovoj, A.M.; Furman, W.I.; Khitrov, V.A.; Jovancevic, N.

    2012-01-01

    A new hypothesis on the dependence of the form of the radiative strength functions of electric and magnetic dipole gamma transitions in a heated nucleus on the excited level density was suggested and tested experimentally. For this purpose, the region of possible values of random values of the level density and radiative strength functions which precisely reproduced experimental intensity of two-step cascades for 41 nuclei from 40K to 200Hg was determined. It was obtained that the suggested hypothesis can provide the maximal increase of radiative strength functions values by order of magnitude in comparison with existing notations as a result of collective effects enhancement. This result points to the necessity to take into account this possibility in existing and future models of radiative strength functions

  14. Chernobyl health effects: radiation or stress?

    International Nuclear Information System (INIS)

    Grinkhal', G.

    1996-01-01

    Consideration is given to results of wide-scale examination of human population, subjected to the effect of radiation in result of Chernobyl accident. The examined contingents consisted of liquidators, evacuated from 30-km zone, people still living in contamination territories, children of irradiated parents and children, who received large radiation doses. High levels of respiratory system diseases, digestive system diseases, cardiovascular diseases and nervous system diseases were revealed for these people. It was revealed that stress, socio-economic and chemical factors played sufficient role in disease incidence. It is shown that fair of radiation may damage more, than radiation itself

  15. Nonlinear Dynamics of Silicon Nanowire Resonator Considering Nonlocal Effect.

    Science.gov (United States)

    Jin, Leisheng; Li, Lijie

    2017-12-01

    In this work, nonlinear dynamics of silicon nanowire resonator considering nonlocal effect has been investigated. For the first time, dynamical parameters (e.g., resonant frequency, Duffing coefficient, and the damping ratio) that directly influence the nonlinear dynamics of the nanostructure have been derived. Subsequently, by calculating their response with the varied nonlocal coefficient, it is unveiled that the nonlocal effect makes more obvious impacts at the starting range (from zero to a small value), while the impact of nonlocal effect becomes weaker when the nonlocal term reaches to a certain threshold value. Furthermore, to characterize the role played by nonlocal effect in exerting influence on nonlinear behaviors such as bifurcation and chaos (typical phenomena in nonlinear dynamics of nanoscale devices), we have calculated the Lyapunov exponents and bifurcation diagram with and without nonlocal effect, and results shows the nonlocal effect causes the most significant effect as the device is at resonance. This work advances the development of nanowire resonators that are working beyond linear regime.

  16. Time-resolved resonance Raman spectroscopy of radiation-chemical processes

    International Nuclear Information System (INIS)

    Tripathi, G.N.R.

    1983-01-01

    A tunable pulsed laser Raman spectrometer for time resolved Raman studies of radiation-chemical processes is described. This apparatus utilizes the state of art optical multichannel detection and analysis techniques for data acquisition and electron pulse radiolysis for initiating the reactions. By using this technique the resonance Raman spectra of intermediates with absorption spectra in the 248-900 nm region, and mean lifetimes > 30 ns can be examined. This apparatus can be used to time resolve the vibrational spectral overlap between transients absorbing in the same region, and to follow their decay kinetics by monitoring the well resolved Raman peaks. For kinetic measurements at millisecond time scale, the Raman technique is preferable over optical absorption method where low frequency noise is quite bothersome. A time resolved Raman study of the pulse radiolytic oxidation of aqueous tetrafluorohydroquinone and p-methoxyphenol is briefly discussed. 15 references, 5 figures

  17. Radioanalytical prediction of radiative capture in 99Mo production via transmutation adiabatic resonance crossing by cyclotron

    CERN Document Server

    Khorshidi, Abdollah; Pazirandeh, Ali; Tenreiro, Claudio; Kadi, Yacine

    2014-01-01

    In this study, the transmutation adiabatic resonance crossing (TARC) concept was estimated in Mo-99 radioisotope production via radiative capture reaction in two designs. The TARC method was composed of moderating neutrons in lead or a composition of lead and water. Additionally, the target was surrounded by a moderator assembly and a graphite reflector district. Produced neutrons were investigated by (p,xn) interactions with 30 MeV and 300 mu A proton beam on tungsten, beryllium, and tantalum targets. The Mo-99 production yield was related to the moderator property, cross section, and sample positioning inside the distinct region of neutron storage as must be proper to achieve gains. Gathered thermal flux of neutrons can contribute to molybdenum isotope production. Moreover, the sample positioning to gain higher production yield was dependent on a greater flux in the length of thermal neutrons and region materials inside the moderator or reflector. When the sample radial distance from Be was 38 cm inside the...

  18. Late effects of radiation: host factors

    International Nuclear Information System (INIS)

    Fry, R.J.M.; Storer, J.B.

    1983-01-01

    The paper discusses the influence of host factors on radiation late effects and in particular cancer. Radiation induces cellular changes that result in initiated cells with a potential to become cancers. The expression of the initiated cells as tumors is influenced, if not determined, by both tissue and systemic factors that are sex-, age-, and species-dependent

  19. Biological radiation effects and radioprotection standards

    International Nuclear Information System (INIS)

    Clerc, H.

    1991-03-01

    In this report, after recalling the mode of action of ionizing radiations, the notions of dose, dose equivalents and the values of natural irradiation, the author describes the biological radiation effects. Then he presents the ICRP recommendations and their applications to the french radioprotection system

  20. Radiation effects on Fischer-Tropsch syntheses

    International Nuclear Information System (INIS)

    Hatada, M.; Matsuda, K.

    1977-01-01

    Radiation effects on Fischer-Tropsch synthesis has been examined using high dose rate electron beams and Fe-Cu-diatomaceous earth catalyst. Yields of saturated hydrocarbons were found to increase by irradiation, but the yields of these compounds were decreased by raising reaction temperature without irradiation, suggesting the presence of radiation chemical process in catalytic reactions. (author)

  1. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a 60Co Magnetic Resonance Image Guidance Radiation Therapy System

    International Nuclear Information System (INIS)

    Wooten, H. Omar; Green, Olga; Yang, Min; DeWees, Todd; Kashani, Rojano; Olsen, Jeff; Michalski, Jeff; Yang, Deshan; Tanderup, Kari; Hu, Yanle; Li, H. Harold; Mutic, Sasa

    2015-01-01

    Purpose: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating 60 Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. Methods and Materials: The ViewRay treatment planning system (Oakwood Village, OH) was used to create 60 Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The 60 Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses and heterogeneity indices (HI) for planning target volumes (PTVs) and maximum, mean, and dose-volume histogram (DVH) values for OARs. Results: All 60 Co IMRT plans achieved PTV coverage and OAR sparing that were similar to linac plans. PTV conformity for 60 Co was within <1% and 3% of linac plans for 100% and 95% prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range <20 Gy, but comparable sparing for organs with mean doses >20 Gy. The mean doses for all 60 Co plan OARs were within clinical tolerances. Conclusions: A commercial 60 Co MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system

  2. Radiation effects in charge coupled devices

    International Nuclear Information System (INIS)

    Williams, R.A.; Nelson, R.D.

    1975-01-01

    Charge coupled devices (CCD s) exhibit a number of advantages (low cost, low power, high bit density) in their several applications (serial memories, imagers, digital filters); however, fairly elementary theoretical considerations indicate that they will be very vulnerable to permanent radiation damage, by both neutrons and ionizing radiation, and to transient upset by pulsed ionizing radiation. Although studies of permanent ionizing-radiation damage in CCD's have been reported, little information has been published concerning their overall nuclear radiation vulnerability. This paper presents a fairly comprehensive experimental study of radiation effects in a 256-cell surface-channel, CCD shift-register. A limited amount of similar work is also presented for a 128-cell surface-channel device and a 130 cell peristaltic CCD shift register. The radiation effects phenomena discussed herein, include transient-ionizing-radiation responses, permanent ionizing- radiation damage to transfer efficiency, charge-carrying capacity and input transfer gate bias, and neutron damage to storage time--determined from dark current and charge-up time measurements

  3. Coherence effects in radiative scattering

    International Nuclear Information System (INIS)

    Knoll, J.; Lenk, R.

    1993-03-01

    The bremsstrahl-production of photons in dense matter is reinvestigated using the example of an exactly solvable quantum mechanical model in one space dimension. Coherence phenomena between successive radiative scatterings among the constituents lead to a modification of the production cross section in the medium relative to the incoherent quasi-free prescription used in kinetic models. Analytic expressions for the correction factor have been derived comparing the quantum rates with the corresponding incoherent quasi-free rates. The result has implications for the kinetic description of all kinds of radiative processes in nucleus-nucleus collisions, both on the level of hadron and parton dynamics. (orig.)

  4. Application of the Electron paramagnetic resonance to the ionizing radiation dosimetry

    International Nuclear Information System (INIS)

    Urena N, F.

    2000-01-01

    The Electron Paramagnetic Resonance (EPR) is defined as the resonant absorption of electromagnetic energy in paramagnetic substances by the spin transition of a non-pairing electron between different energy levels in presence of a magnetic field. (Slighter, 1989). One of the more important characteristic of EPR is that the electron spin levels are subdivided by the electron interaction with the magnetic dipoles of the nearby nucleus giving occasion for a spectral structure called hyperfine structure. In this kind of interactions two limit cases are distinguished: 1. when the non-pairing electron is located in a central ion surrounded of atoms belonging to coordinate molecules. 2. When a non-pairing electron interactioning in the same form with a number of equivalent nucleus, which is common in organic radicals, these will give as result spectra. Some EPR spectrometer can be used to dosimetric purposes by free radicals via. In this work, it is presented the application of EPR to dosimetry of ionizing radiations by free radicals via which allows to determinations of high doses. (Author)

  5. Physics of radiation effects in crystals

    CERN Document Server

    Johnson, RA

    1986-01-01

    ``Physics of Radiation Effects in Crystals'' is presented in two parts. The first part covers the general background and theory of radiation effects in crystals, including the theory describing the generation of crystal lattice defects by radiation, the kinetic approach to the study of the disposition of these defects and the effects of the diffusion of these defects on alloy compositions and phases. Specific problems of current interest are treated in the second part and include anisotropic dimensional changes in x-uranium, zirconium and graphite, acceleration of thermal creep in reactor ma

  6. Effects of radiation on scintillating fiber performance

    International Nuclear Information System (INIS)

    Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E.; Young, K.G.; Carey, R.; Rothman, M.; Sulak, L.; Worstell, W.; Parr, H.

    1992-01-01

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain needed information and calculational procedures used in performing predications for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. These calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented

  7. Effects of radiation on scintillating fiber performance

    International Nuclear Information System (INIS)

    Young, K.G.; Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E.; Carey, R.; Rothman, M.; Sulak, L.; Worstell, W.; Paar, H.

    1993-01-01

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain desired information and calculational procedures used in performing predictions for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. The calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented

  8. Characteristics of natural background external radiation and effective dose equivalent

    International Nuclear Information System (INIS)

    Fujimoto, Kenzo

    1989-01-01

    The two sources of natural radiation - cosmic rays and primordial radionuclides - are described. The factors affecting radiation doses received from natural radiation and the calculation of effective dose equivalent due to natural radiation are discussed. 10 figs., 3 tabs

  9. Chaos-induced resonant effects and its control

    International Nuclear Information System (INIS)

    Zambrano, Samuel; Casado, Jose M.; Sanjuan, Miguel A.F.

    2007-01-01

    This Letter shows that a suitable chaotic signal can induce resonant effects analogous to those observed in presence of noise in a bistable system under periodic forcing. By constructing groups of chaotic and random perturbations with similar one-time statistics we show that in some cases chaos and noise induce indistinguishable resonant effects. This reinforces the conjecture by which in some situations where noise is supposed to play a key role maybe chaos is the key ingredient. Here we also show that the presence of a chaotic signal as the perturbation leading to a resonance opens new control perspectives based on our ability to stabilize chaos in different periodic orbits. A discussion of the possible implications of these facts is also presented at the end of the Letter

  10. Resonant nuclear battery may aid in mitigating the greenhouse effect

    International Nuclear Information System (INIS)

    Brown, P.M.

    1989-01-01

    A new process for the direct conversion of radioactive decay energy directly into electricity of a usable form is currently being developed by Peripheral Systems, Inc. of Portland, Oregon. United States Patent 4,835,433 was issued May 30, 1989 to protect this Resonant Nuclear Power Supply. When developed, this system promises cheap, reliable power from a package small and light enough to be mobile and an energy density great enough for use as a space-based power supply. One of the potential domestic applications could be to power electric automobiles. Use in highly populated areas would have a tremendous beneficial effect on the ecology. The principle of operation for the resonant nuclear power supply is an LCR (inductance capacitance resistance) resonant tank circuit oscillating at its self-resonant frequency (at resonance, the inductive reactance and the capacitive reactance cancel to leave the ohmic resistance of the circuit as the only major loss of energy). A means for absorbing the natural radioactive decay energy emitted from an alpha or beta source is provided in the primary tank circuit and contributes an amount of energy, by means of the beta voltaic effect, in excess of the energy required to sustain the oscillation of the LCR primary tank. A transformer is impedance matched to this oscillating primary circuit for efficient energy transfer of the excess energy to a secondary output circuit, which yields net electrical power in a high-frequency usable form to drive a load

  11. Effect of bevacizumab on radiation necrosis of the brain

    International Nuclear Information System (INIS)

    Gonzalez, Javier; Kumar, Ashok J.; Conrad, Charles A.; Levin, Victor A.

    2007-01-01

    Purpose: Because blocking vascular endothelial growth factor (VEGF) from reaching leaky capillaries is a logical strategy for the treatment of radiation necrosis, we reasoned that bevacizumab might be an effective treatment of radiation necrosis. Patients and Methods: Fifteen patients with malignant brain tumors were treated with bevacizumab or bevacizumab combination for their tumor on either a 5 mg/kg/2-week or 7.5 mg/kg/3-week schedule. Radiation necrosis was diagnosed in 8 of these patients on the basis of magnetic resonance imaging (MRI) and biopsy. MRI studies were obtained before treatment and at 6-week to 8-week intervals. Results: Of the 8 patients with radiation necrosis, posttreatment MRI performed an average of 8.1 weeks after the start of bevacizumab therapy showed a reduction in all 8 patients in both the MRI fluid-attenuated inversion-recovery (FLAIR) abnormalities and T1-weighted post-Gd-contrast abnormalities. The average area change in the T1-weighted post-Gd-contrast abnormalities was 48% (±22 SD), and the average change in the FLAIR images was 60% (±18 SD). The average reduction in daily dexamethasone requirements was 8.6 mg (±3.6). Conclusion: Bevacizumab, alone and in combination with other agents, can reduce radiation necrosis by decreasing capillary leakage and the associated brain edema. Our findings will need to be confirmed in a randomized trial to determine the optimal duration of treatment

  12. Overview of radiation effects research in photonics

    Science.gov (United States)

    Webb, Robert C.; Cohn, Lewis M.; Taylor, Edward W.; Greenwell, Roger A.

    1995-05-01

    A brief overview of ongoing radiation effects research in photonics is presented focusing on integrated optic and acousto-optic components. A short summary of radiation-induced effects in electro-optic modulators, detector arrays, and other photonic technologies is presented along with extensive references. The coordinated radiation effects studies among researchers within the Tri-Service Organizations and international experimental teams are beginning to demonstrate consistent measurements of radiation-induced effects in photonic components and confirming earlier reported data. This paper will present an overview of these coordinated investigations and focus on key research being conducted with the AFMC Phillips Laboratory, Naval Research Laboratory, Defence Nuclear Agency, NATO Nuclear Effects Task Group, and the Tri-Service Photonics Coordinating Committee.

  13. Effects of small radiation doses

    International Nuclear Information System (INIS)

    Fuchs, G.

    1986-01-01

    The term 'small radiation dosis' means doses of about (1 rem), fractions of one rem as well as doses of a few rem. Doses like these are encountered in various practical fields, e.g. in X-ray diagnosis, in the environment and in radiation protection rules. The knowledge about small doses is derived from the same two forces, on which the radiobiology of human beings nearly is based: interpretation of the Hiroshima and Nagasaki data, as well as the experience from radiotherapy. Careful interpretation of Hiroshima dates do not provide any evidence that small doses can induce cancer, fetal malformations or genetic damage. Yet in radiotherapy of various diseases, e.g. inflammations, doses of about 1 Gy (100 rad) do no harm to the patients. According to a widespread hypothesis even very small doses may induce some types of radiation damage ('no threshold'). Nevertheless an alternative view is justified. At present no decision can be made between these two alternatives, but the usefullness of radiology is definitely better established than any damage calculated by theories or extrapolations. Based on experience any exaggerated fear of radiations can be met. (author)

  14. Directional effects in transitional resonance spectra and group constants

    International Nuclear Information System (INIS)

    Hill, R.N.; Oh, K.O.; Rhodes, J.D.

    1989-01-01

    Analytical exploratory investigations indicate that transition effects such as streaming cause a considerable spatial variation in the neutron spectra across resonances; streaming leads to opposite effects in the forward and backward directions. The neglect of this coupled spatial/angular variations of the transitory resonance spectra is an approximation that is common to all current group constant generation methodologies. This paper presents a description of the spatial/angular coupling of the neutron flux across isolated resonances. It appears to be necessary to differentiate between forward-and backward-directed neutron flux components or even to consider components in narrower angular cones. The effects are illustrated for an isolated actinide resonance in a simplified fast reactor blanket problem. The resonance spectra of the directional flux components φ + and φ - , and even more so the 90-deg cone components, are shown to deviate significantly from the infinite medium approximation, and the differences increase with penetration. The charges in φ + lead to a decreasing scattering group constant that enhances neutron transmission; the changes in φ - lead to an increasing group constant inhibiting backward scattering. Therefore, the changes in the forward-and backward-directed spectra both lead to increased neutron transmission. Conversely, the flux (φ = φ + +φ - ) is shown to agree closely with the infinite medium approximation both in the analytical formulas and in the numerical solution. The directional effect cancel in the summation. The forward-and backward-directed flux components are used as weighting spectra to illustrate the group constant changes for a single resonance

  15. Effect of radiation processing on meat tenderisation

    International Nuclear Information System (INIS)

    Kanatt, Sweetie R.; Chawla, S.P.; Sharma, Arun

    2015-01-01

    The effect of radiation processing (0, 2.5, 5 and 10 kGy) on the tenderness of three types of popularly consumed meat in India namely chicken, lamb and buffalo was investigated. In irradiated meat samples dose dependant reduction in water holding capacity, cooking yield and shear force was observed. Reduction in shear force upon radiation processing was more pronounced in buffalo meat. Protein and collagen solubility as well as TCA soluble protein content increased on irradiation. Radiation processing of meat samples resulted in some change in colour of meat. Results suggested that irradiation leads to dose dependant tenderization of meat. Radiation processing of meat at a dose of 2.5 kGy improved its texture and had acceptable odour. - Highlights: • Effect of radiation processing on tenderness of three meat systems was evaluated. • Dose dependant reduction in shear force seen in buffalo meat. • Collagen solubility increased with irradiation

  16. Effects of gamma radiation in tomato seeds

    Energy Technology Data Exchange (ETDEWEB)

    Wiendl, Toni A.; Wiendl, Fritz W.; Franco, Suely S.H.; Franco, Jose G.; Althur, Valter, E-mail: tawiendl@hotmail.com, E-mail: gilmita@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Arthur, Paula B., E-mail: arthur@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2013-07-01

    Tomato dry seeds of the hybrid 'Gladiador' F1 were exposed to low doses of gamma radiation from Co-60 source at 0,509 kGy tax rate in order to study stimulation effects of radiation on germination and plant growth. Eight treatments radiation doses were applied as follows: 0 (control); 2,5; 5,0; 7,5; 10,0; 12,5; 15,0; 20,0 Gy. Seed germination as well as green fruits number, harvested fruit number, fruit weight and total production were assessed to identify occurrence of stimulation. Tomato seeds and plants were handled as for usual tomato production in Brazil. Low doses of gamma radiation treatment in the seeds stimulate germination and substantially increase fruit number and total production up to 86% at 10 Gy dose. There are evidences that the use of low doses of gamma radiation can stimulate germination and plant production thus, showing hormetic effects. (author)

  17. Radiation effect on rocket engine performance

    Science.gov (United States)

    Chiu, Huei-Huang; Kross, K. W.; Krebsbach, A. N.

    1990-01-01

    Critical problem areas involving the effect of radiation on the combustion of bipropellants are addressed by formulating a universal scaling law in combination with a radiation-enhanced vaporization combustion model. Numerical algorithms are developed and data pertaining to the Variable Thrust Engine (VTE) and the Space Shuttle Main Engine (SSME) are used to conduct parametric sensitivity studies to predict the principal intercoupling effects of radiation. The analysis reveals that low-enthalpy engines, such as the VTE, are vulnerable to a substantial performance setback due to radiative loss, whereas the performance of high-enthalpy engines such as the SSME are hardly affected over a broad range of engine operation. Combustion enhancement by radiative heating of the propellant has a significant impact on propellants with high absorptivity.

  18. Effects of gamma radiation in tomato seeds

    International Nuclear Information System (INIS)

    Wiendl, Toni A.; Wiendl, Fritz W.; Franco, Suely S.H.; Franco, Jose G.; Althur, Valter; Arthur, Paula B.

    2013-01-01

    Tomato dry seeds of the hybrid 'Gladiador' F1 were exposed to low doses of gamma radiation from Co-60 source at 0,509 kGy tax rate in order to study stimulation effects of radiation on germination and plant growth. Eight treatments radiation doses were applied as follows: 0 (control); 2,5; 5,0; 7,5; 10,0; 12,5; 15,0; 20,0 Gy. Seed germination as well as green fruits number, harvested fruit number, fruit weight and total production were assessed to identify occurrence of stimulation. Tomato seeds and plants were handled as for usual tomato production in Brazil. Low doses of gamma radiation treatment in the seeds stimulate germination and substantially increase fruit number and total production up to 86% at 10 Gy dose. There are evidences that the use of low doses of gamma radiation can stimulate germination and plant production thus, showing hormetic effects. (author)

  19. Biological effects of proton radiation: an update

    International Nuclear Information System (INIS)

    Girdhani, S.; Hlatky, L.; Sachs, R.

    2015-01-01

    Proton radiation provides significant dosimetric advantages when compared with gamma radiation due to its superior energy deposition characteristics. Although the physical aspects of proton radiobiology are well understood, biological and clinical endpoints are understudied. The current practice to assume the relative biological effectiveness of low linear energy transfer (LET) protons to be a generic value of about 1.1 relative to photons likely obscures important unrecognised differentials in biological response between these radiation qualities. A deeper understanding of the biological properties induced by proton radiation would have both radiobiological and clinical impact. This article briefly points to some of the literature pertinent to the effects of protons on tissue-level processes that modify disease progression, such as angiogenesis, cell invasion and cancer metastasis. Recent findings hint that proton radiation may, in addition to offering improved radio-therapeutic targeting, be a means to provide a new dimension for increasing therapeutic benefits for patients by manipulating these tissue-level processes. (authors)

  20. The effects of ionizing radiation on man

    International Nuclear Information System (INIS)

    Watson, G.M.

    1975-08-01

    This paper describes the major effects of ionizing radiation on man and the relationship between such effects and radiation dose, with the conclusion that standards of radiological safety must be based on the carcinogenetic and mutagenic properties of ionizing radiation. Man is exposed to radiation from natural sources and from man-made sources. Exposure from the latter should be regulated but, since there is little observational or experimental evidence for predicting the effects of the very small doses likely to be required for adequate standards of safety, it is necessary to infer them from what is seen at high doses. Because the formal relationship between dose and effect is not fully understood, simplifying assumptions are necessary to estimate the effects of low doses. Two such assumptions are conventionally used; that there is a linear relationship between dose and effect at all levels of dose, and that the rate at which a dose of radiation is given does not alter the magnitude of the effect. These assumptions are thought to be conservative, that is they will not lead to an underestimation of the effects of small radiation doses although they may give an over-estimate. (author)

  1. Magnetic Resonance Imaging-Based Radiation-Absorbed Dose Estimation of Ho-166 Microspheres in Liver Radioembolization

    NARCIS (Netherlands)

    Seevinck, Peter R.; van de Maat, Gerrit H.; de Wit, Tim C.; Vente, Maarten A. D.; Nijsen, Johannes F. W.; Bakker, Chris J. G.

    2012-01-01

    Purpose: To investigate the potential of magnetic resonance imaging (MRI) for accurate assessment of the three-dimensional Ho-166 activity distribution to estimate radiation-absorbed dose distributions in Ho-166-loaded poly (L-lactic acid) microsphere (Ho-166-PLLA-MS) liver radioembolization.

  2. Radiation dosimetry for residents of the Chernobyl region: a comparison of cytogenetic and electron spin resonance methods

    Energy Technology Data Exchange (ETDEWEB)

    Serezhenkov, V A; Mordvintcev, P I; Vanin, A F; Voevodskaya, N V [AN SSSR, Moscow (Russian Federation). Inst. Fizicheskoj Khimii; Domracheva, E V; Kulikov, S M; Kuznetsov, S A; Schklovsky-Kordi, N E; Vorobiev, A I [National Center for Haematology, Moscow (Russian Federation); Klevezal, G A; Sukhovskaya, L I [Russian Academy of Science, Moscow (Russian Federation). Inst. of Developmental Biology

    1992-01-01

    Persons from the Gomel region of Byelorussia who were irradiated by the Chernobyl reactor accident have been studied. Estimations of their radiation doses using electron spin resonance spectrometry of dental enamel showed good agreement with dosimetry by chromosomal analysis of blood lymphocytes. (author).

  3. Nonlinear resonance islands and modulational effects in a proton synchrotron

    International Nuclear Information System (INIS)

    Satogata, T.J.

    1993-01-01

    The authors examine one-dimensional and two-dimensional nonlinear resonance islands created in the transverse phase space of a proton synchrotron by nonlinear magnets. The authors examine application of the theoretical framework constructed to the phenomenon of modulational diffusion in a collider model of the Fermilab Tevatron. For the one-dimensional resonance island system, the authors examine the effects of two types of modulational perturbations on the stability of these resonance islands: Tune modulation and beta function modulation. Hamiltonian models are presented which predict stability boundaries that depend on only three parameters: The strength and frequency of the modulation and the frequency of small oscillations inside the resonance island. The tune modulation model is successfully tested in experiment, where frequency domain analysis coupled with tune modulation is demonstrated to be useful in measuring the strength of a nonlinear resonance. Nonlinear resonance islands are examined in two transverse dimensions in the presence of coupling and linearly independent crossing resonances. The authors present a first-order Hamiltonian model which predicts fixed point locations, but does not reproduce small oscillation frequencies seen in tracking. Particle tracking is presented which shows evidence of two-dimensional persistent signals, and the authors make suggestions on methods for observing such signals in future experiment. The authors apply the tune modulation stability diagram to the explicitly two-dimensional phenomenon of modulational diffusion in the Fermilab Tevatron with beam-beam kicks as the source of nonlinearity. The amplitude growth created by this mechanism in simulation is exponential rather than root-time as predicted by modulational diffusion models. The authors comment upon the luminosity and lifetime limitations such a mechanism implies in a proton storage ring

  4. Fast Neutron Radiation Effects on Bacillus Subtili

    International Nuclear Information System (INIS)

    Chen Xiaoming; Zhang Jianguo; Chu Shijin; Ren Zhenglong; Zheng Chun; Yang Chengde; Tan Bisheng

    2009-01-01

    To examine the sterilizing effect and mechanism of neutron radiation, Bacillus subtilis var. niger. strain (ATCC 9372) spores were irradiated with the fast neutron from the Chinese fast burst reactor II(CFBR-II). The plate-count results indicated that the D 10 value was 384.6 Gy with a neutron radiation dose rate of 7.4 Gy/min. The rudimental catalase activity of the spores declined obviously with the increase in the radiation dose. Meanwhile, under the scanning electron microscope, no visible influence of the neutron radiation on the spore configuration was detected even if the dose was increased to 4 kGy. The content and distribution of DNA double-strand breaks induced by neutron radiation at different doses were measured and quantified by pulsed-field gel electrophoresis (PFGE). Further analysis of the DNA release percentage (PR), the DNA breakage level (L), and the average molecular weight, indicated that DNA fragments were obviously distributed around the 5 kb regions at different radiation doses, which suggests that some points in the DNA molecule were sensitive to neutron radiation. Both PR and L varied regularly to some extent with the increase in radiation dose. Thus neutron radiation has a high sterilization power, and can induce falling enzyme activity and DNA breakage in Bacillus subtilis spores

  5. Radiative effects of global MODIS cloud regimes

    Science.gov (United States)

    Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Kato, Seiji

    2018-01-01

    We update previously published MODIS global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 dataset. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux datasets. Our results clearly show the CRs are radiatively distinct in terms of shortwave, longwave and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance datasets suffering from imperfect spatiotemporal matching depend on CR, and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations. PMID:29619289

  6. Radiative Effects of Global MODIS Cloud Regimes

    Science.gov (United States)

    Oraiopoulos, Lazaros; Cho, Nayeong; Lee, Dong Min; Kato, Seiji

    2016-01-01

    We update previously published MODIS global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 dataset. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux datasets. Our results clearly show the CRs are radiatively distinct in terms of shortwave, longwave and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance datasets suffering from imperfect spatiotemporal matching depend on CR, and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations.

  7. Predicted solar cell edge radiation effects

    International Nuclear Information System (INIS)

    Gates, M.T.

    1993-01-01

    The Advanced Solar Cell Orbital Test (ASCOT) will test six types of solar cells in a high energy proton environment. During the design of the experiment a question was raised about the effects of proton radiation incident on the edge of the solar cells and whether edge radiation shielding was required. Historical geosynchronous data indicated that edge radiation damage is not detectable over the normal end of life solar cell degradation; however because the ASCOT radiation environment has a much higher and more energetic fluence of protons, considerably more edge damage is expected. A computer analysis of the problem was made by modeling the expected radiation damage at the cell edge and using a network model of small interconnected solar cells to predict degradation in the cell's electrical output. The model indicated that the deepest penetration of edge radiation was at the top of the cell near the junction where the protons have access to the cell through the low density cell/cover adhesive layer. The network model indicated that the cells could tolerate high fluences at their edge as long as there was high electrical resistance between the edge radiated region and the contact system on top of the cell. The predicted edge radiation related loss was less than 2% of maximum power for GaAs/Ge solar cells. As a result, no edge radiation protection was used for ASCOT

  8. The Effects of Ionizing Radiation on Mammalian Cells.

    Science.gov (United States)

    Biaglow, John E.

    1981-01-01

    Discusses the effects of radiation on dividing cells and factors influencing these effects; also briefly reviews the radical mechanism for radiation damage. Emphasizes the importance of oxygen in radiation effects. (CS)

  9. RADIOFREQUENCY AND MICROWAVE RADIATION HEALTH EFFECTS AND OCCUPATIONAL EXPOSURE

    Directory of Open Access Journals (Sweden)

    Ivana Damnjanović

    2011-12-01

    Full Text Available In the recent years, there have been considerable discussion and concern about the possible hazards of RF/MW radiation. More recently, the growth and development in personal mobile communications have focused attention on the frequencies associated with this technology. A number of studies have examined the health effects of RF/MW electromagnetic fields (EMFs, originating from occupational exposure, hobbies, or residence near the radio or television transmitters. Particularly controversial are the biophysical mechanisms by which these RF fields may affect biological systems. General health effects reviews explore possible carcinogenic, reproductive and neurological effects. Health effects by exposure source have been observed in radar traffic devices, wireless communications with cellular phones, radio transmission, and magnetic resonance imaging (MRI. Several epidemiological surveys have suggested associations with non-specific complaints such as headache, tiredness, sleep disturbance, loss of memory, and dizziness. These findings, which echo reports of illness associated with other types of radiofrequency (RF radiation, relate not only to the use of mobile phones, but also to residence near the mobile phone base stations and other settings involving occupational exposure. The biological effects suggest that some precautions are necessary, and preventive approaches are highly recommended. Further researches are required to give more information about the effects of microwave radiation on our health, especially in occupational setting and professionally exposed workers.

  10. Monte Carlo treatment of resonance-radiation imprisonment in fluorescent lamps—revisited

    Science.gov (United States)

    Anderson, James B.

    2016-12-01

    We reported in 1985 a Monte Carlo treatment of the imprisonment of the 253.7 nm resonance radiation from mercury in the mercury-argon discharge of fluorescent lamps. The calculated spectra of the emitted radiation were found in good agreement with measured spectra. The addition of the isotope mercury-196 to natural mercury was found, also in agreement with experiments, to increase lamp efficiency. In this paper we report the extension of the earlier work with increased accuracy, analysis of photon exit-time distributions, recycling of energy released in quenching, analysis of dynamic similarity for different lamp sizes, variation of Mrozowski transfer rates, prediction and analysis of the hyperfine ultra-violet spectra, and optimization of tailored mercury isotope mixtures for increased lamp efficiency. The spectra were found insensitive to the extent of quenching and recycling. The optimized mixtures were found to increase efficiencies by as much as 5% for several lamp configurations. Optimization without increasing the mercury-196 fraction was found to increase efficiencies by nearly 1% for several configurations.

  11. Monte Carlo treatment of resonance-radiation imprisonment in fluorescent lamps—revisited

    International Nuclear Information System (INIS)

    Anderson, James B

    2016-01-01

    We reported in 1985 a Monte Carlo treatment of the imprisonment of the 253.7 nm resonance radiation from mercury in the mercury–argon discharge of fluorescent lamps. The calculated spectra of the emitted radiation were found in good agreement with measured spectra. The addition of the isotope mercury-196 to natural mercury was found, also in agreement with experiments, to increase lamp efficiency. In this paper we report the extension of the earlier work with increased accuracy, analysis of photon exit-time distributions, recycling of energy released in quenching, analysis of dynamic similarity for different lamp sizes, variation of Mrozowski transfer rates, prediction and analysis of the hyperfine ultra-violet spectra, and optimization of tailored mercury isotope mixtures for increased lamp efficiency. The spectra were found insensitive to the extent of quenching and recycling. The optimized mixtures were found to increase efficiencies by as much as 5% for several lamp configurations. Optimization without increasing the mercury-196 fraction was found to increase efficiencies by nearly 1% for several configurations. (paper)

  12. Internal friction, microstructure, and radiation effects

    International Nuclear Information System (INIS)

    Wechsler, M.S.; Sommer, W.F.; Davidson, D.R.

    1984-01-01

    A brief review is given of internal friction relaxation peaks and background internal friction. The microstructural origin of the internal friction is discussed. Particular emphasis is placed on radiation effects

  13. Effects of solar radiation on glass

    Science.gov (United States)

    Tucker, Dennis S.; Kinser, Donald L.

    1991-01-01

    The effects of solar radiation of selected glasses are reported. Optical property degradation is studied using UV-Vis spectrophotometry. Strength changes are measured using a concentric ring bend test. Direct fracture toughness measurements using an indentation test are planned.

  14. Decomposition of radiational effects of model feedbacks

    International Nuclear Information System (INIS)

    Ellsaesser, H.W.; MacCracken, M.C.; Potter, G.L.; Mitchell, C.S.

    1981-08-01

    Three separate doubled CO 2 experiments with the statistical dynamic model are used to illustrate efforts to study the climate dynamics, feedbacks, and interrelationships of meteorological parameters by decomposing and isolating their individual effects on radiation transport

  15. Sterilizing radiation effects on selected polymers

    International Nuclear Information System (INIS)

    Skiens, W.E.

    1979-03-01

    The mechanism of radiation effects and their industrial applications are discussed for the following classes of polymers: thermoplastics, thermosets, elastomers, films and fibers, and adhesives/coatings/potting compounds. 35 references, 3 tables

  16. Radiobiology: Biologic effects of ionizing radiations

    International Nuclear Information System (INIS)

    Held, K.D.

    1987-01-01

    The biologic effects after exposure to ionizing radiation, such as cell death or tissue injury, result from a chain of complex physical, chemical, metabolic, and histologic events. The time scale of these radiation actions spans many orders of magnitude. The physical absorption of ionizing radiation occurs in about 10 -18 s, while late carcinogenic and genetic effects are expressed years or even generations later. Collectively, these effects form the science of radiobiology. Many of the concepts discussed in this chapter have been developed through the study of effects generated in tissues by external radiation sources, but they apply generally and often specifically to internally distributed radiopharmaceuticals which form the central topic of this book

  17. Genetic effects of ionizing radiations in Eucaryocytes

    International Nuclear Information System (INIS)

    Jullien, Pierre

    1976-01-01

    The litterature on the genetic effects of ionizing radiations is reviewed, especially as concerns specific loci or chromosome mutations. Extrapolation from one species to another is considered as well as extra-nuclear mutations [fr

  18. The effect of ionizing radiation on cyanophyta

    International Nuclear Information System (INIS)

    Kondrat'eva, N.V.; Shevchenko, T.F.; Golubkova, M.G.

    1989-01-01

    Publication data on the effect of ionizing radiation on cyanophyta are generalized. The conclusion about the presence of premises for forming cyanophyta radiobiology as special direction of procaryotic algae investigation is made

  19. [Effects of radiation exposure on human body].

    Science.gov (United States)

    Kamiya, Kenji; Sasatani, Megumi

    2012-03-01

    There are two types of radiation health effect; acute disorder and late on-set disorder. Acute disorder is a deterministic effect that the symptoms appear by exposure above a threshold. Tissues and cells that compose the human body have different radiation sensitivity respectively, and the symptoms appear in order, from highly radiosensitive tissues. The clinical symptoms of acute disorder begin with a decrease in lymphocytes, and then the symptoms appear such as alopecia, skin erythema, hematopoietic damage, gastrointestinal damage, central nervous system damage with increasing radiation dose. Regarding the late on-set disorder, a predominant health effect is the cancer among the symptoms of such as cancer, non-cancer disease and genetic effect. Cancer and genetic effect are recognized as stochastic effects without the threshold. When radiation dose is equal to or more than 100 mSv, it is observed that the cancer risk by radiation exposure increases linearly with an increase in dose. On the other hand, the risk of developing cancer through low-dose radiation exposure, less 100 mSv, has not yet been clarified scientifically. Although uncertainty still remains regarding low level risk estimation, ICRP propound LNT model and conduct radiation protection in accordance with LNT model in the low-dose and low-dose rate radiation from a position of radiation protection. Meanwhile, the mechanism of radiation damage has been gradually clarified. The initial event of radiation-induced diseases is thought to be the damage to genome such as radiation-induced DNA double-strand breaks. Recently, it is clarified that our cells could recognize genome damage and induce the diverse cell response to maintain genome integrity. This phenomenon is called DNA damage response which induces the cell cycle arrest, DNA repair, apoptosis, cell senescence and so on. These responses act in the direction to maintain genome integrity against genome damage, however, the death of large number of

  20. Effects of radiations on ornamental fish

    International Nuclear Information System (INIS)

    Anita; Kalyankar, Amol D.; Ohlyan, Sunita; Gupta, R.K.

    2012-01-01

    Radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiations: ionizing and non-ionizing. Ultraviolet, X-rays, and gamma rays are some examples of radiation. 'Ornamental fish' is designed for aquatic hobbyists and the aquatic industry for several purposes. UV light has two primary uses in fish culture: Controlling green water and disinfecting the water supply. Many proponents of UV disinfection sometimes overlook the additional benefits relating to ornamental fish; those being that cleaner water reduces the stress on the fish by not having to fight off diseases, thus enhancing its immune system and leading to faster growth and more brilliant colors. Ultraviolet sterilizers are often used in aquaria to help control unwanted microorganisms in the water. UV radiation also ensures that exposed pathogens cannot reproduce, thus decreasing the likelihood of a disease outbreak in an aquarium. Despite of these benefits, the ill-effects of radiations cannot be ruled out. Ultraviolet Radiation-induced DNA Damage is seen in the skin of the Platyfish Xiphophorus. Higher radiation doses may cause the gastrointestinal syndrome that leads to defects of the intestinal mucosa barrier with successive contamination of musculature. Exposure to UV radiation can kill the fish and induce sublethal effects in embryos, larvae and adults. The change in skin includes irregularity of skin surface, epidermal oedema, necrosis etc. Irradiation may badly influence the textural attributes of fish muscle. (author)

  1. Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Rankine, Leith J., E-mail: Leith_Rankine@med.unc.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Mein, Stewart [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Cai, Bin; Curcuru, Austen [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Juang, Titania; Miles, Devin [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Mutic, Sasa; Wang, Yuhe [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Oldham, Mark [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Li, H. Harold, E-mail: hli@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States)

    2017-04-01

    Purpose: To validate the dosimetric accuracy of a commercially available magnetic resonance guided intensity modulated radiation therapy (MRgIMRT) system using a hybrid approach: 3-dimensional (3D) measurements and Monte Carlo calculations. Methods and Materials: We used PRESAGE radiochromic plastic dosimeters with remote optical computed tomography readout to perform 3D high-resolution measurements, following a novel remote dosimetry protocol. We followed the intensity modulated radiation therapy commissioning recommendations of American Association of Physicists in Medicine Task Group 119, adapted to incorporate 3D data. Preliminary tests (“AP” and “3D-Bands”) were delivered to 9.5-cm usable diameter cylindrical PRESAGE dosimeters to validate the treatment planning system (TPS) for nonmodulated deliveries; assess the sensitivity, uniformity, and rotational symmetry of the PRESAGE dosimeters; and test the robustness of the remote dosimetry protocol. Following this, 4 clinical MRgIMRT plans (“MultiTarget,” “Prostate,” “Head/Neck,” and “C-Shape”) were measured using 13-cm usable diameter PRESAGE dosimeters. For all plans, 3D-γ (3% or 3 mm global, 10% threshold) passing rates were calculated and 3D-γ maps were examined. Point doses were measured with an IBA-CC01 ionization chamber for validation of absolute dose. Finally, by use of an in-house-developed, GPU-accelerated Monte Carlo algorithm (gPENELOPE), we independently calculated dose for all 6 Task Group 119 plans and compared against the TPS. Results: For PRESAGE measurements, 3D-γ analysis yielded passing rates of 98.7%, 99.2%, 98.5%, 98.0%, 99.2%, and 90.7% for AP, 3D-Bands, MultiTarget, Prostate, Head/Neck, and C-Shape, respectively. Ion chamber measurements were within an average of 0.5% (±1.1%) from the TPS dose. Monte Carlo calculations demonstrated good agreement with the TPS, with a mean 3D-γ passing rate of 98.5% ± 1.9% using a stricter 2%/2-mm criterion. Conclusions: We

  2. Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System

    International Nuclear Information System (INIS)

    Rankine, Leith J.; Mein, Stewart; Cai, Bin; Curcuru, Austen; Juang, Titania; Miles, Devin; Mutic, Sasa; Wang, Yuhe; Oldham, Mark; Li, H. Harold

    2017-01-01

    Purpose: To validate the dosimetric accuracy of a commercially available magnetic resonance guided intensity modulated radiation therapy (MRgIMRT) system using a hybrid approach: 3-dimensional (3D) measurements and Monte Carlo calculations. Methods and Materials: We used PRESAGE radiochromic plastic dosimeters with remote optical computed tomography readout to perform 3D high-resolution measurements, following a novel remote dosimetry protocol. We followed the intensity modulated radiation therapy commissioning recommendations of American Association of Physicists in Medicine Task Group 119, adapted to incorporate 3D data. Preliminary tests (“AP” and “3D-Bands”) were delivered to 9.5-cm usable diameter cylindrical PRESAGE dosimeters to validate the treatment planning system (TPS) for nonmodulated deliveries; assess the sensitivity, uniformity, and rotational symmetry of the PRESAGE dosimeters; and test the robustness of the remote dosimetry protocol. Following this, 4 clinical MRgIMRT plans (“MultiTarget,” “Prostate,” “Head/Neck,” and “C-Shape”) were measured using 13-cm usable diameter PRESAGE dosimeters. For all plans, 3D-γ (3% or 3 mm global, 10% threshold) passing rates were calculated and 3D-γ maps were examined. Point doses were measured with an IBA-CC01 ionization chamber for validation of absolute dose. Finally, by use of an in-house-developed, GPU-accelerated Monte Carlo algorithm (gPENELOPE), we independently calculated dose for all 6 Task Group 119 plans and compared against the TPS. Results: For PRESAGE measurements, 3D-γ analysis yielded passing rates of 98.7%, 99.2%, 98.5%, 98.0%, 99.2%, and 90.7% for AP, 3D-Bands, MultiTarget, Prostate, Head/Neck, and C-Shape, respectively. Ion chamber measurements were within an average of 0.5% (±1.1%) from the TPS dose. Monte Carlo calculations demonstrated good agreement with the TPS, with a mean 3D-γ passing rate of 98.5% ± 1.9% using a stricter 2%/2-mm criterion. Conclusions: We

  3. Surface and temperature effects in isovector giant resonances

    International Nuclear Information System (INIS)

    Lipparini, E.; Stringari, S.

    1988-01-01

    Using the liquid droplet model (LDM) we investigate three different sum rules for the isovector dipole and monopole excitations. Analytical formulae are derived for the excitation energies of these resonances and the predictions are compared with experiments. The role of the surface and the effects of temperature are explicitly discussed. (orig.)

  4. Effective Hamiltonians in quantum physics: resonances and geometric phase

    International Nuclear Information System (INIS)

    Rau, A R P; Uskov, D

    2006-01-01

    Effective Hamiltonians are often used in quantum physics, both in time-dependent and time-independent contexts. Analogies are drawn between the two usages, the discussion framed particularly for the geometric phase of a time-dependent Hamiltonian and for resonances as stationary states of a time-independent Hamiltonian

  5. Effect of magnetic resonance imaging characteristics on uterine fibroid treatment

    Directory of Open Access Journals (Sweden)

    Duc NM

    2018-04-01

    Full Text Available Nguyen Minh Duc, Huynh Quang HuyDepartment of Radiology, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, VietnamAbstract: Uterine fibroids are the most common gynecological benign tumors adversely affecting the quality of life of women of a reproductive age. Magnetic resonance imaging (MRI is efficient at localizing the site of lesions and characterizing uterine fibroids before treatment. Understanding the different characteristics of uterine fibroids on MRI is essential, because it not only enables prompt diagnosis, but also guides the development of suitable therapeutic methods. This pictorial review demonstrates the effect of MRI features on uterine fibroid treatment. Keywords: uterine fibroids, characteristics, magnetic resonance imaging, treatments

  6. Tunneling effect in cavity-resonator-coupled arrays

    International Nuclear Information System (INIS)

    Ma Hua; Xu Zhuo; Qu Shao-Bo; Zhang Jie-Qiu; Wang Jia-Fu; Liang Chang-Hong

    2013-01-01

    The quantum tunneling effect (QTE) in a cavity-resonator-coupled (CRC) array was analytically and numerically investigated. The underlying mechanism was interpreted by treating electromagnetic waves as photons, and then was generalized to acoustic waves and matter waves. It is indicated that for the three kinds of waves, the QTE can be excited by cavity resonance in a CRC array, resulting in sub-wavelength transparency through the narrow splits between cavities. This opens up opportunities for designing new types of crystals based on CRC arrays, which may find potential applications such as quantum devices, micro-optic transmission, and acoustic manipulation. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  7. Effect of ionizing radiations on connective tissue

    International Nuclear Information System (INIS)

    Altman, K.I.; Gerber, G.B.

    1980-01-01

    The effects of ionizing radiations on connective tissue in lung, heart, vasculature, kidney, skin, and skeletal tissues are reviewed. Special emphasis is given to the effect of ionizing radiations on vasculo-connective tissue and fibrotic changes following radiation-induced injury to organs and tissues. In order to put the subject matter in proper prospective, the general biochemistry, physiology, and pathology of connective tissue is reviewed briefly together with the participation of connective tissue in disease. The review closes with an assessment of future problems and an enumeration and discussion of important, as yet unanswered questions

  8. Radiation abuse and its effects

    Energy Technology Data Exchange (ETDEWEB)

    Halm, A

    1976-06-01

    This paper delves into overuse practiced in diagnostic radiography. The conventional attitudes to low-dose irradiation are critically examined, as is the MPD related to individual radiosensitivity. Concern is expressed that a sizeable proportion of radiologists ignore important aspects of the Code of Practice and this attitude is readily emulated in the hospital setting. The author advocates education within the medical profession and the community on the risks involved in radiation abuse and the benefits derived from justified exposures to x rays.

  9. Radiation Effects in M and NEMS

    Science.gov (United States)

    2016-03-31

    electrical basis of operation of M&NEM structures? In particular, cumulative damage by non - ionizing energy loss can, in principle, alter the... Radiation Effects in M&NEMS Michael Alles, Kirill Bolotin, Alex Zettl, Brian Homeijer, Jim Davidson, Ronald Schrimpf, Robert Reed, Dan Fleetwood...understanding radiation effects on the relevant properties of the constituent materials and structures, particularly advanced 2D materials, and the

  10. Modifiers of radiation effects in the eye

    Science.gov (United States)

    Kleiman, Norman J.; Stewart, Fiona A.; Hall, Eric J.

    2017-11-01

    World events, including the threat of radiological terrorism and the fear of nuclear accidents, have highlighted an urgent need to develop medical countermeasures to prevent or reduce radiation injury. Similarly, plans for manned spaceflight to a near-Earth asteroid or journey to Mars raise serious concerns about long-term effects of space radiation on human health and the availability of suitable therapeutic interventions. At the same time, the need to protect normal tissue from the deleterious effects of radiotherapy has driven considerable research into the design of effective radioprotectors. For more than 70 years, animal models of radiation cataract have been utilized to test the short and long-term efficacy of various radiation countermeasures. While some compounds, most notably the Walter Reed (WR) class of radioprotectors, have reported limited effectiveness when given before exposure to low-LET radiation, the human toxicity of these molecules at effective doses limits their usefulness. Furthermore, while there has been considerable testing of eye responses to X- and gamma irradiation, there is limited information about using such models to limit the injurious effects of heavy ions and neutrons on eye tissue. A new class of radioprotector molecules, including the sulfhydryl compound PrC-210, are reported to be effective at much lower doses and with far less side effects. Their ability to modify ocular radiation damage has not yet been examined. The ability to non-invasively measure sensitive, radiation-induced ocular changes over long periods of time makes eye models an attractive option to test the radioprotective and radiation mitigating abilities of new novel compounds.

  11. Radiation effects on eye components

    International Nuclear Information System (INIS)

    Durchschlag, H.; Fochler, C.; Abraham, K.; Kulawik, B.

    1998-01-01

    The radiation damage (X-ray, UV light) of the most important components of the vertebrate eye (crystallins and other proteins, hyaluronic acid, vitreous, aqueous humour, ascorbic acid) has been investigated by various methods of physical chemistry. UV absorption and fluorescence spectroscopy as well as circular dichroism unveiled changes of the chromophores/fluorophores of the constituent biopolymers and low-molecular components, together with alterations of helix content and the occurrence of aggregation. Size-exclusion chromatography, analytical ultracentrifugation, densimetry, viscometry and light scattering experiments monitored changes of the global structure of proteins and polysaccharides involved. Electrophoreses allowed conclusions on fragmentation, unfolding and crosslinking. Analytical methods provided information regarding the integrity of groups of special concern (SH, SS) and revealed the existence of stable noxious species (H 2 O 2 ). By means of various measures and additives, manifold modifications of the impact of both ionizing and nonionizing radiation may be achieved. Caused by differences in the primary reactions, eye polymers are protected efficaciously by typical OH radical scavengers against X-irradiation, whereas compounds which exhibit absorption behavior in the UV range turn out to act as potent protectives ('chemical filters') against UV light. A few substances, such as ascorbate, are able to provide protection against both sorts of radiation and are even able to exhibit a slight chemical repair of already damaged particles. The results obtained are of importance for understanding pathological alterations of the eye (loss of transparency, cataractogenesis) and for developing new strategies for protection and repair of eye components. (author)

  12. Radiation effects on biodegradable polyesters

    International Nuclear Information System (INIS)

    Hiroshi Mitomo; Darmawan Darwis; Fumio Yoshii; Keizo Makuuchi

    1999-01-01

    Poly(3-hydroxybutyrate) [P(3HB)] and its copolymer poly(3-hydroxybutyrate-co-3hydroxyvalerate) [P(3HB-co-3HV)] are microbial biodegradable polyesters produced by many types of bacteria. Poly(butylene succinate) (PBS) and poly(E-caprolactone) (PCL) are also biodegradable synthetic polyesters which have been commercialized. These thermoplastics are expected for wide usage in environmental protection and blocompatible applications. Radiation grafting of hydrophilic monomers onto many polymers, e.g., polyethylene and polypropylene has been studied mainly for biomedical applications. In the present study, radiation-induced graft polymerization of vinyl monomers onto PHB and P(3HB-co-3HV) was carried out and improvement of their properties was studied. Changes in the properties and biodegradability were compared with the degree of grafting. Radiation-induced crosslinking of PBS and PCL which relatively show thermal and irradiation stability was also carried out to improve their thermal stability or processability. Irradiation to PBS and PCL mainly resulted in crosslinking and characterization of these crosslinked polyesters was investigated

  13. Perturbed effects at radiation physics

    International Nuclear Information System (INIS)

    Külahcı, Fatih; Şen, Zekâi

    2013-01-01

    Perturbation methodology is applied in order to assess the linear attenuation coefficient, mass attenuation coefficient and cross-section behavior with random components in the basic variables such as the radiation amounts frequently used in the radiation physics and chemistry. Additionally, layer attenuation coefficient (LAC) and perturbed LAC (PLAC) are proposed for different contact materials. Perturbation methodology provides opportunity to obtain results with random deviations from the average behavior of each variable that enters the whole mathematical expression. The basic photon intensity variation expression as the inverse exponential power law (as Beer–Lambert's law) is adopted for perturbation method exposition. Perturbed results are presented not only in terms of the mean but additionally the standard deviation and the correlation coefficients. Such perturbation expressions provide one to assess small random variability in basic variables. - Highlights: • Perturbation methodology is applied to Radiation Physics. • Layer attenuation coefficient (LAC) and perturbed LAC are proposed for contact materials. • Perturbed linear attenuation coefficient is proposed. • Perturbed mass attenuation coefficient (PMAC) is proposed. • Perturbed cross-section is proposed

  14. Experimental Verification of Isotropic Radiation from a Coherent Dipole Source via Electric-Field-Driven LC Resonator Metamaterials

    Science.gov (United States)

    Tichit, Paul-Henri; Burokur, Shah Nawaz; Qiu, Cheng-Wei; de Lustrac, André

    2013-09-01

    It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator’s gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present.

  15. Effective dose: a radiation protection quantity

    CERN Document Server

    Menzel, H G

    2012-01-01

    Modern radiation protection is based on the principles of justification, limitation, and optimisation. Assessment of radiation risks for individuals or groups of individuals is, however, not a primary objective of radiological protection. The implementation of the principles of limitation and optimisation requires an appropriate quantification of radiation exposure. The International Commission on Radiological Protection (ICRP) has introduced effective dose as the principal radiological protection quantity to be used for setting and controlling dose limits for stochastic effects in the regulatory context, and for the practical implementation of the optimisation principle. Effective dose is the tissue weighted sum of radiation weighted organ and tissue doses of a reference person from exposure to external irradiations and internal emitters. The specific normalised values of tissue weighting factors are defined by ICRP for individual tissues, and used as an approximate age- and sex-averaged representation of th...

  16. Non-targeted effects of ionising radiation

    International Nuclear Information System (INIS)

    Belyakov, O.V.

    2008-01-01

    The universality of the target theory of radiation-induced effects is challenged by observations on non-targeted effects such as bystander effects and genomic instability. Essential features of non-targeted effects are that they do not require direct nuclear exposure by radiation and they are particularly significant at low doses. This new evidence suggests a need for a new paradigm in radiation biology. The new paradigm would cover both the classical (targeted) and the non-targeted effects. New aspects include the role of cellular communication and tissue-level responses. A better understanding of non-targeted effects may have important consequences for health risk assessment and, consequently, on radiation protection. Non-targeted effects may contribute to the estimation of cancer risk from occupational, medical and environmental exposures. In particular, they may have implications for the applicability of the Linear-No-Threshold (LNT) model in extrapolating radiation risk data into the low-dose region. This also means that the adequacy of the concept of dose to estimate risk is challenged by these findings. Moreover, these effects may provide new mechanistic explanations for the development of non-cancer diseases. Further research is required to determine if these effects, typically measured in cell cultures, are applicable in tissue level, whole animals, and ultimately in humans. (orig.)

  17. Biological effects of high-energy radiation

    International Nuclear Information System (INIS)

    Curtis, S.B.

    1976-01-01

    The biological effects of high-energy radiation are reviewed, with emphasis on the effects of the hadronic component. Proton and helium ion effects are similar to those of the more conventional and sparsely ionizing x- and γ-radiation. Heavy-ions are known to be more biologically effective, but the long term hazard from accumulated damage has yet to be assessed. Some evidence of widely varying but dramatically increased effectiveness of very high-energy (approximately 70 GeV) hadron beams is reviewed. Finally, the importance of the neutron component in many situations around high-energy accelerators is pointed out

  18. Biological effects and hazards of radiation exposure

    International Nuclear Information System (INIS)

    Boas, J.F.; Solomon, S.B.

    1990-01-01

    Radiation induced carcinogenesis and mutagenesis form the main risk to health from exposure to low levels of radiation. This risk effects can be at least qualitatively understood by considering the effects of radiation on cell DNA. Whilst exposure to high levels of radiation results in a number of identifiable effects, exposure to low levels of radiation may result in effects which only manifest themselves after many years. Risk estimates for low levels of radiation have been derived on the basis of a number of assumptions. In the case of uranium mine workers a major hazard arises from the inhalation of radon daughters. Whilst the correlation between radon daughter exposure and lung cancer incidence is well established, the numerical value of the risk factor is the subject of controversy. ICRP 50 gives a value of 10 cases per 10 6 person-years at risk per WLM (range 5-15 x 10 -6 PYR -1 WLM -1 ). The effect of smoking on lung cancer incidence rates amongst miners is also controversial. Nevertheless, smoking by miners should be discouraged

  19. Measurement of the effect of the lattice pitch on the effective resonance integral of natural uranium

    Energy Technology Data Exchange (ETDEWEB)

    Krcevinac, S; Takac, S [Institut za nuklearne nauke ' Boris Kidric' , Vinca, Belgrade (Yugoslavia)

    1966-07-01

    The analytical theory of resonance absorption, as well as the numerical Monte Carlo method, allows calculation of the resonance integral. However, it is based on specific approximations so it may be used accurately enough in a limited number of cases. Likewise, insufficiently accurate know ledge of the basic nuclear constants (e.g. resonance parameters, etc.) used as input data in analytical calculation, leads to inaccurate determination of the resonance integral.. Therefore, experimental determination of the effective resonance integral is still indispensable. In some cases the experimental results are used as the exclusive source of information, or as the basis for the semiempirical technique of calculation, and in others as a check of the new theoretical procedures. There are several experimental methods of direct determination of the resonance integral: the activation method (1,2), the reactor oscillator and the danger coefficient method. Indirectly, using the results of critical experiments, it is possible to determine correlated values of the effective resonance integral. The present work investigates the dependence of the effective resonance integral on the lattice pitch. Theoretically, the dependence is determined starting from Wigner's rational approximation in which the lattice is characterized by the effective ratio (S/M) {sup X}. Later this allows correlation between the lattice resonance integral and the resonance integral of the single rod (the rod in infinite medium). Using two approximations for Dancoff's factor we give the measured functional dependence of the effective resonance integral on the effective (S/M){sup X} ratio. To determine the resonance integral experimentally we used the activation method and the differential technique of measuring absorption distribution in U{sup 2}38. Since, because of the use of cadmium in determining the cadmium ratio in the fuel rod the effective lattice pitch cannot be defined with certain reliability, besides

  20. Electronic Paramagnetic Resonance of irradiated nails: challenges for a dosimetry in radiation accidents; Ressonancia Paramagnetica Eletronica de unhas irradiadas: desafios para uma dosimetria em acidentes radiologicos

    Energy Technology Data Exchange (ETDEWEB)

    Giannoni, Ricardo A., E-mail: giannoni@ird.gov.br [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Rodrigues Junior, Orlando [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    The purpose of this work is to characterize samples of human nails exposed to high doses of radiation, applying the technique of Electron Paramagnetic Resonance (EPR). The objective is to establish a dose response study that allow determine the absorbed dose by exposed individuals in situations of radiological accidents, in a retrospective form. Samples of human nails were collected and afterward irradiated with gamma radiation, and received dose of 20 Gy. The EPR measurement performed on the samples, before irradiation, permitted the signal identification of the components associated with effects caused by the mechanical stress during the fingernail cutting, the so-called mechanically induced signal (MIS). After the irradiation, different species of free radicals were identified, the so-called radiation induced signal (RIS). (author)

  1. Radiation abuse and its effects

    International Nuclear Information System (INIS)

    Halm, A.

    1976-01-01

    This paper delves into overuse practiced in diagnostic radiography. The conventional attitudes to low-dose irradiation are critically examined, as is the MPD related to individual radiosensitivity. Concern is expressed that a sizeable proportion of radiologists ignore important aspects of the Code of Practice and this attitude is readily emulated in the hospital setting. The author advocates education within the medical profession and the community on the risks involved in radiation abuse and the benefits derived from justified exposures to x rays. (author)

  2. Spatial Precision in Magnetic Resonance Imaging–Guided Radiation Therapy: The Role of Geometric Distortion

    Energy Technology Data Exchange (ETDEWEB)

    Weygand, Joseph, E-mail: jw2899@columbia.edu [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas (United States); Fuller, Clifton David [The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas (United States); Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ibbott, Geoffrey S. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas (United States); Mohamed, Abdallah S.R. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Oncology and Nuclear Medicine, Alexandria University, Alexandria (Egypt); Ding, Yao [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Yang, Jinzhong [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas (United States); Hwang, Ken-Pin [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang, Jihong [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas (United States)

    2016-07-15

    Because magnetic resonance imaging–guided radiation therapy (MRIgRT) offers exquisite soft tissue contrast and the ability to image tissues in arbitrary planes, the interest in this technology has increased dramatically in recent years. However, intrinsic geometric distortion stemming from both the system hardware and the magnetic properties of the patient affects MR images and compromises the spatial integrity of MRI-based radiation treatment planning, given that for real-time MRIgRT, precision within 2 mm is desired. In this article, we discuss the causes of geometric distortion, describe some well-known distortion correction algorithms, and review geometric distortion measurements from 12 studies, while taking into account relevant imaging parameters. Eleven of the studies reported phantom measurements quantifying system-dependent geometric distortion, while 2 studies reported simulation data quantifying magnetic susceptibility–induced geometric distortion. Of the 11 studies investigating system-dependent geometric distortion, 5 reported maximum measurements less than 2 mm. The simulation studies demonstrated that magnetic susceptibility–induced distortion is typically smaller than system-dependent distortion but still nonnegligible, with maximum distortion ranging from 2.1 to 2.6 mm at a field strength of 1.5 T. As expected, anatomic landmarks containing interfaces between air and soft tissue had the largest distortions. The evidence indicates that geometric distortion reduces the spatial integrity of MRI-based radiation treatment planning and likely diminishes the efficacy of MRIgRT. Better phantom measurement techniques and more effective distortion correction algorithms are needed to achieve the desired spatial precision.

  3. Soft X-ray radiation damage in EM-CCDs used for Resonant Inelastic X-ray Scattering

    Science.gov (United States)

    Gopinath, D.; Soman, M.; Holland, A.; Keelan, J.; Hall, D.; Holland, K.; Colebrook, D.

    2018-02-01

    Advancement in synchrotron and free electron laser facilities means that X-ray beams with higher intensity than ever before are being created. The high brilliance of the X-ray beam, as well as the ability to use a range of X-ray energies, means that they can be used in a wide range of applications. One such application is Resonant Inelastic X-ray Scattering (RIXS). RIXS uses the intense and tuneable X-ray beams in order to investigate the electronic structure of materials. The photons are focused onto a sample material and the scattered X-ray beam is diffracted off a high resolution grating to disperse the X-ray energies onto a position sensitive detector. Whilst several factors affect the total system energy resolution, the performance of RIXS experiments can be limited by the spatial resolution of the detector used. Electron-Multiplying CCDs (EM-CCDs) at high gain in combination with centroiding of the photon charge cloud across several detector pixels can lead to sub-pixel spatial resolution of 2-3 μm. X-ray radiation can cause damage to CCDs through ionisation damage resulting in increases in dark current and/or a shift in flat band voltage. Understanding the effect of radiation damage on EM-CCDs is important in order to predict lifetime as well as the change in performance over time. Two CCD-97s were taken to PTB at BESSY II and irradiated with large doses of soft X-rays in order to probe the front and back surfaces of the device. The dark current was shown to decay over time with two different exponential components to it. This paper will discuss the use of EM-CCDs for readout of RIXS spectrometers, and limitations on spatial resolution, together with any limitations on instrument use which may arise from X-ray-induced radiation damage.

  4. Spatial Precision in Magnetic Resonance Imaging–Guided Radiation Therapy: The Role of Geometric Distortion

    International Nuclear Information System (INIS)

    Weygand, Joseph; Fuller, Clifton David; Ibbott, Geoffrey S.; Mohamed, Abdallah S.R.; Ding, Yao; Yang, Jinzhong; Hwang, Ken-Pin; Wang, Jihong

    2016-01-01

    Because magnetic resonance imaging–guided radiation therapy (MRIgRT) offers exquisite soft tissue contrast and the ability to image tissues in arbitrary planes, the interest in this technology has increased dramatically in recent years. However, intrinsic geometric distortion stemming from both the system hardware and the magnetic properties of the patient affects MR images and compromises the spatial integrity of MRI-based radiation treatment planning, given that for real-time MRIgRT, precision within 2 mm is desired. In this article, we discuss the causes of geometric distortion, describe some well-known distortion correction algorithms, and review geometric distortion measurements from 12 studies, while taking into account relevant imaging parameters. Eleven of the studies reported phantom measurements quantifying system-dependent geometric distortion, while 2 studies reported simulation data quantifying magnetic susceptibility–induced geometric distortion. Of the 11 studies investigating system-dependent geometric distortion, 5 reported maximum measurements less than 2 mm. The simulation studies demonstrated that magnetic susceptibility–induced distortion is typically smaller than system-dependent distortion but still nonnegligible, with maximum distortion ranging from 2.1 to 2.6 mm at a field strength of 1.5 T. As expected, anatomic landmarks containing interfaces between air and soft tissue had the largest distortions. The evidence indicates that geometric distortion reduces the spatial integrity of MRI-based radiation treatment planning and likely diminishes the efficacy of MRIgRT. Better phantom measurement techniques and more effective distortion correction algorithms are needed to achieve the desired spatial precision.

  5. Effects produced by nuclear radiation in powdery milk; Efectos producidos por radiaciones nucleares en leches en polvo

    Energy Technology Data Exchange (ETDEWEB)

    Urena N, F; Reyes G, A [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    The objective of this work is to determine the chemical effects produced by the gamma rays and beta particles radiations on the powdery milk. This work treats on the Pre-dose analysis, sampling radiating, electron spin resonance, acidity, proteins, aminoacids, lactose, fatty acids, peroxides, as well as its experimental results. (Author)

  6. Photoionization pathways and thresholds in generation of Lyman-α radiation by resonant four-wave mixing in Kr-Ar mixture

    Directory of Open Access Journals (Sweden)

    Oleg A. Louchev

    2016-09-01

    Full Text Available We develop a set of analytical approximations for the estimation of the combined effect of various photoionization processes involved in the resonant four-wave mixing generation of ns pulsed Lyman-α (L-α radiation by using 212.556 nm and 820-845 nm laser radiation pulses in Kr-Ar mixture: (i multi-photon ionization, (ii step-wise (2+1-photon ionization via the resonant 2-photon excitation of Kr followed by 1-photon ionization and (iii laser-induced avalanche ionization produced by generated free electrons. Developed expressions validated by order of magnitude estimations and available experimental data allow us to identify the area for the operation under high input laser intensities avoiding the onset of full-scale discharge, loss of efficiency and inhibition of generated L-α radiation. Calculations made reveal an opportunity for scaling up the output energy of the experimentally generated pulsed L-α radiation without significant enhancement of photoionization.

  7. Photoionization pathways and thresholds in generation of Lyman-α radiation by resonant four-wave mixing in Kr-Ar mixture

    Science.gov (United States)

    Louchev, Oleg A.; Saito, Norihito; Oishi, Yu; Miyazaki, Koji; Okamura, Kotaro; Nakamura, Jumpei; Iwasaki, Masahiko; Wada, Satoshi

    2016-09-01

    We develop a set of analytical approximations for the estimation of the combined effect of various photoionization processes involved in the resonant four-wave mixing generation of ns pulsed Lyman-α (L-α ) radiation by using 212.556 nm and 820-845 nm laser radiation pulses in Kr-Ar mixture: (i) multi-photon ionization, (ii) step-wise (2+1)-photon ionization via the resonant 2-photon excitation of Kr followed by 1-photon ionization and (iii) laser-induced avalanche ionization produced by generated free electrons. Developed expressions validated by order of magnitude estimations and available experimental data allow us to identify the area for the operation under high input laser intensities avoiding the onset of full-scale discharge, loss of efficiency and inhibition of generated L-α radiation. Calculations made reveal an opportunity for scaling up the output energy of the experimentally generated pulsed L-α radiation without significant enhancement of photoionization.

  8. Semiclassical description of resonant tunnel effect: bifurcations and periodic orbits in the resonant current

    International Nuclear Information System (INIS)

    Rouben, D.C.

    1997-01-01

    A semiclassical method for resonant tunneling in a quantum well in the presence of a magnetic field tilted with regard to an electric field is developed. In particular a semiclassical formula is derived for the total current of electrons after the second barrier of the quantum well. The contribution of the stable and unstable orbits is studied. It appears that the parameters which describe the classical chaos in the quantum well have an important effect on the tunneling current. A numerical experiment is led, the contributions to the current of some particular orbits are evaluated and the results are compared with those given by the quantum theory. (A.C.)

  9. Mode splitting effect in FEMs with oversized Bragg resonators

    Energy Technology Data Exchange (ETDEWEB)

    Peskov, N. Yu.; Sergeev, A. S. [Institute of Applied Physics Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Kaminsky, A. K.; Perelstein, E. A.; Sedykh, S. N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kuzikov, S. V. [Institute of Applied Physics Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Nizhegorodsky State University, Nizhny Novgorod (Russian Federation)

    2016-07-15

    Splitting of the fundamental mode in an oversized Bragg resonator with a step of the corrugation phase, which operates over the feedback loop involving the waveguide waves of different transverse structures, was found to be the result of mutual influence of the neighboring zones of the Bragg scattering. Theoretical description of this effect was developed within the framework of the advanced (four-wave) coupled-wave approach. It is shown that mode splitting reduces the selective properties, restricts the output power, and decreases the stability of the narrow-band operating regime in the free-electron maser (FEM) oscillators based on such resonators. The results of the theoretical analysis were confirmed by 3D simulations and “cold” microwave tests. Experimental data on Bragg resonators with different parameters in a 30-GHz FEM are presented. The possibility of reducing the mode splitting by profiling the corrugation parameters is shown. The use of the mode splitting effect for the output power enhancement by passive compression of the double-frequency pulse generated in the FEM with such a resonator is discussed.

  10. A few words about resonances in the electroweak effective Lagrangian

    Energy Technology Data Exchange (ETDEWEB)

    Rosell, Ignasi [Departamento de Ciencias Físicas, Matemáticas y de la Computación, Universidad CEU Cardenal Herrera, c/ Sant Bartomeu 55, 46115 Alfara del Patriarca, València (Spain); Pich, Antonio; Santos, Joaquín [Departament de Física Teòrica, IFIC, Universitat de València – CSIC, Apt. Correus 22085, 46071 València (Spain); Sanz-Cillero, Juan José [Departamento de Física Teórica and Instituto Física Teórica, IFT-UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2016-01-22

    Contrary to a widely spread believe, we have demonstrated that strongly coupled electroweak models including both a light Higgs-like boson and massive spin-1 resonances are not in conflict with experimental constraints on the oblique S and T parameters. We use an effective Lagrangian implementing the chiral symmetry breaking SU (2){sub L} ⊗ SU (2){sub R} → SU (2){sub L+R} that contains the Standard Model gauge bosons coupled to the electroweak Goldstones, one Higgs-like scalar state h with mass m{sub h} = 126 GeV and the lightest vector and axial-vector resonance multiplets V and A. We have considered the one-loop calculation of S and T in order to study the viability of these strongly-coupled scenarios, being short-distance constraints and dispersive relations the main ingredients of the calculation. Once we have constrained the resonance parameters, we do a first approach to the determination of the low energy constants of the electroweak effective theory at low energies (without resonances). We show this determination in the case of the purely Higgsless bosonic Lagrangian.

  11. Biological Effects of Ionizing Radiation

    International Nuclear Information System (INIS)

    Durand, J.L.

    2000-01-01

    The aim of this work is to verify the existence of the adaptive response phenomenon induced by low doses of ionizing radiation in living cells.A wild-type yeast Saccharomyces cerevisiae (Baker's yeast) was chosen as the biological target.As a parameter to quantify the sensibility of the target to radiation, the Lethal Dose 50 (LD50 ) was observed. In our experimental condition a value of (60 ± 1) Gy was measured for LD50 with Dose Rate of (0.44 ± 0.03) Gy/min. The method employed to show up the adaptive response phenomenon consisted in exposing the sample to low ''conditioning'' doses, which would initiate these mechanisms. Later the samples with and without conditioning were exposed to higher ''challenging'' doses (such as LD50), and the surviving fractions were compared. In order to maximize the differences, the doses and the time between irradiations were varied. The best results were obtained with both a conditioning dose of (0.44 ± 0.03) Gy and a waiting time of 2 hs until the application of the challenging dose. Following this procedures the 80% of the conditioned samples has survived, after receiving the application of the LD50. The adaptive response phenomenon was also verified for a wide range of challenging doses

  12. Radiation effects on ion exchange materials

    International Nuclear Information System (INIS)

    Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

    1977-11-01

    An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references

  13. Radiation effects on ion exchange materials

    Energy Technology Data Exchange (ETDEWEB)

    Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

    1977-11-01

    An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references.

  14. Radiation-induced effects in organic systems. Final report

    International Nuclear Information System (INIS)

    Johnsen, R.H.

    1982-01-01

    This project, which is of twenty-seven years duration, has been devoted to furthering our basic understanding of the processes involved in the absorption and distribution of high-energy radiation in organic molecules. The early phases of the work were concerned with the gross chemical effects of radiation and included studies in a number of important classes of organic compounds including alcohols, aliphatic acids, aliphatic hydrocarbons, and aromatic hydrocarbons. Basic information was acquired through these studies that has led to a better understanding of the effects of high-energy radiation on condensed media. During this period the so-called protective effect of low concentrations of aromatic hydrocarbons was also studied. A contribution of lasting significance at this time was the development of a technique for the post-radiolysis analysis of trapped free radicals by photochemical means. A comprehensive series of papers on the reactions of thermal hydrogen atoms with frozen organic substrates represented the beginning of a new phase in the approach to the problems of radiation chemistry in this laboratory. Since that time the general philosophy guided the research has been to single out events or processes suspected of contributing to the gross-radiation effect and study them in isolation. Thus from 1970 on efforts were devoted to charge-exchange processes, ionization efficiencies (w-values), radical decay process in solids and ion-dissociation reactions. The first by means of a modified time-of-flight mass spectrometer, the second utilizing an ionization chamber constructed in the FSU shops, the third using electron spin resonance detection, and the last involving the use of a dual mass spectrometer, solid target system invented in our laboratory. The most productive of these efforts has been the radical decay work

  15. Development of 119Sn nuclear resonance scattering of synchrotron radiation and first applications

    International Nuclear Information System (INIS)

    Barla, A.

    2001-01-01

    In the framework of this thesis the NRS technique has been developed and applied, for the first time at the European Synchrotron Radiation Facility, at the resonance of 119 Sn. Elastic nuclear forward scattering (NFS) is ideal for studies of hyperfine interactions, where information about the electronic and magnetic properties of solids is obtained. On the other hand nuclear inelastic scattering (NIS) allows one to study the phonon density of states (DOS) of Moessbauer isotopes in various kinds of systems. In the first stage, technical developments have been made, particularly with regards the used optical elements. A key point has been the construction of a high resolution monochromator (HRM) for the resonance of 119 Sn, with an energy resolution of about 0.65 meV, perfectly suited to perform NIS experiments. A second HRM optimised in throughput has been constructed and used, in combination with focussing elements (bent crystals and compound refractive lenses), to perform NFS experiments at very high pressure. For the first applications of 119 Sn NIS, the phonon DOS of β-Sn has been directly determined from the NIS spectra measured at T = 100 K and T = 300 K. An excellent agreement has been found with the phonon DOS obtained theoretically by previous calculations. Moreover, dynamical and thermodynamical properties of β-Sn extracted from the determined DOS, such as the Lamb-Moessbauer factor and the specific heat, are found to be in good agreement with previously published results. As a first application of 119 Sn NFS experiments at high pressure, the system U(In 1-x Sn x ) 3 has been chosen. (orig.)

  16. Development of {sup 119}Sn nuclear resonance scattering of synchrotron radiation and first applications

    Energy Technology Data Exchange (ETDEWEB)

    Barla, A.

    2001-07-01

    In the framework of this thesis the NRS technique has been developed and applied, for the first time at the European Synchrotron Radiation Facility, at the resonance of {sup 119}Sn. Elastic nuclear forward scattering (NFS) is ideal for studies of hyperfine interactions, where information about the electronic and magnetic properties of solids is obtained. On the other hand nuclear inelastic scattering (NIS) allows one to study the phonon density of states (DOS) of Moessbauer isotopes in various kinds of systems. In the first stage, technical developments have been made, particularly with regards the used optical elements. A key point has been the construction of a high resolution monochromator (HRM) for the resonance of {sup 119}Sn, with an energy resolution of about 0.65 meV, perfectly suited to perform NIS experiments. A second HRM optimised in throughput has been constructed and used, in combination with focussing elements (bent crystals and compound refractive lenses), to perform NFS experiments at very high pressure. For the first applications of {sup 119}Sn NIS, the phonon DOS of {beta}-Sn has been directly determined from the NIS spectra measured at T = 100 K and T = 300 K. An excellent agreement has been found with the phonon DOS obtained theoretically by previous calculations. Moreover, dynamical and thermodynamical properties of {beta}-Sn extracted from the determined DOS, such as the Lamb-Moessbauer factor and the specific heat, are found to be in good agreement with previously published results. As a first application of {sup 119}Sn NFS experiments at high pressure, the system U(In{sub 1-x}Sn{sub x}){sub 3} has been chosen. (orig.)

  17. Radiation effects on optical data transmission systems

    International Nuclear Information System (INIS)

    Leskovar, B.

    1989-01-01

    The state of the art of optical transmitters, low loss fiber waveguides and receivers in both steady state and pulsed radiation environments is reviewed and summarized. Emphasis is placed on the effects of irradiation on the performance of light emitting and laser diodes, optical fiber waveguides and photodiodes. The influence of radiation-induced attenuation of optical fibers due to total dose, dose rate, time after irradiation, temperature, radiation history, photobleaching, OH and impurity content, dopant type and concentration is described. The performance of candidate components of the transmission system intended for deployment in the Superconducting Super Collider Detector and primary beam tunnel nuclear environment is discussed

  18. Radiation effects on the integrity of paper

    International Nuclear Information System (INIS)

    Otero D'Almeida, Maria Luiza; Medeiros Barbosa, Patricia de Souza; Boaratti, Marcelo Fernando Guerra; Borrely, Sueli Ivone

    2009-01-01

    Books and documents attacked by fungi and insects have already been treated by radiation for disinfestations purposes. However, there is still need to investigate the influence of radiation on the cellulose paper structure. The aim of this research was to study the effects of radiation on paper properties, especially those related to strength and appearance. Paper sheets for this study were prepared in the laboratory, using bleached eucalyptus pulp as raw material. No additives were used to concentrate the attention only on the effects of irradiation on the pure cellulose matrix. The samples were irradiated at IPEN's 60 Co Gammacell irradiator with six radiation doses, from 3 to 15 kGy at the dose rate 0.817 Gy/s. The properties of paper sheets were tested after irradiation and compared with unirradiated samples according to ISO methods. No significant changes were detected in paper samples irradiated up to 15 kGy.

  19. Effect of gamma radiation on Campylobacter jejuni

    International Nuclear Information System (INIS)

    Lambert, J.D.; Maxcy, R.B.

    1984-01-01

    Radiation resistance of Campylobacter jejuni in broth, ground beef, and ground turkey meat was determined using dose levels from 0-200 Krad at -30 +/- 10 0 C, at 0-5 0 C, and at 30 +/- 10 0 C. Irradiation at -30 0 C increased radiation resistance of cultures in ground meats; broth cultures were not greatly influenced by temperature. The effect of culture age on radiation resistance was also evaluated using cells in various physiological phases. Age did not have a pronounced effect on radiation resistance. The largest D 10 value for C. jejuni was 32 Krad, which was less than D 10 values commonly reported for salmonellae. 20 references, 4 figures

  20. Noninvasive monitoring of radiation-induced treatment response using proton magnetic resonance spectroscopy and diffusion-weighted magnetic resonance imaging in a colorectal tumor model

    International Nuclear Information System (INIS)

    Seierstad, Therese; Roe, Kathrine; Olsen, Dag Rune

    2007-01-01

    Background and purpose: To examine whether in vivo proton magnetic resonance spectroscopy ( 1 H MRS) and diffusion-weighted magnetic resonance imaging (DW-MRI) can monitor radiation-induced changes in HT29 xenografts in mice. Materials and methods: HT29 xenografts in mice received a dose of 15 Gy. In vivo 1 H MRS and DW-MRI were acquired pretreatment and 1, 3, 6 and 10 days post-irradiation. After imaging, tumors were excised for histological analysis. The amounts of necrosis, fibrosis and viable cells in the cross sections were scored and compared to changes in apparent diffusion coefficient (ADC) and choline/water ratio. Results: Radiation-induced necrosis in the xenografts was observed as increased tumor ADC. In-growth of fibrosis three days post-irradiation restricting water mobility was accompanied by decreased tumor ADC. Choline/water ratio correlated with metabolic activity and tumor growth. Conclusions: ADC and choline/water ratio assessed by in vivo DW-MRI and 1 H MRS depicts radiation-induced changes in HT29 xenografts following irradiation

  1. Radiation effects on DNA methylation in mice

    International Nuclear Information System (INIS)

    Komura, J.; Kurishita, A.; Miyamura, Y.; Ono, T.; Tawa, R.; Sakurai, H.

    1992-01-01

    Effects of ionizing radiation on DNA methylation in liver, brain and spleen were examined by high performance liquid chromatography (HPLC). The total methylated cytosine level in the genome was reduced within 8 hours after 3.8 Gy of irradiation in liver of adult mice. But no appreciable effect was observed in brain and spleen. When mice were irradiated at newborn, liver DNA revealed no change in methylated cytosine level. Even though slight effects of radiation were detected in he methylation of the c-myc and c-fos genes, they were only temporary and no long-term effects were observed. These data suggest that the effect of radiation on DNA methylation in vivo is not prevailing a DNA damage, but rather influenced much through biological parameters. (author)

  2. Resonance effects in projectile-electron loss in relativistic collisions with excited atoms

    International Nuclear Information System (INIS)

    Voitkiv, A B

    2005-01-01

    The theory of electron loss from projectile-ions in relativistic ion-atom collisions is extended to the case of collisions with excited atoms. The main feature of such collisions is a resonance which can emerge between electron transitions in the ion and atom. The resonance becomes possible due to the Doppler effect and has a well-defined impact energy threshold. In the resonance case, the ion-atom interaction is transmitted by the radiation field and the range of this interaction becomes extremely long. Because of this the presence of other atoms in the target medium and the size of the space occupied by the medium have to be taken into account and it turns out that microscopic loss cross sections may be strongly dependent on such macroscopic parameters as the target density, temperature and size. We consider both the total and differential loss cross sections and show that the resonance can have a strong impact on the angular and energy distributions of electrons emitted from the projectiles and the total number of electron loss events

  3. Evidence for beneficial low level radiation effects and radiation hormesis

    International Nuclear Information System (INIS)

    Feinendegen, L.E.

    2005-01-01

    Low doses in the mGy range cause a dual effect on cellular DNA. One effect concerns a relatively low probability of DNA damage per energy deposition event and it increases proportional with dose, with possible bystander effects operating. This damage at background radiation exposure is orders of magnitudes lower than that from endogenous sources, such as ROS. The other effect at comparable doses brings an easily obeservable adaptive protection against DNA damage from any, mainly endogenous sources, depending on cell type, species, and metabolism. Protective responses express adaptive responses to metabolic perturbations and also mimic oxygen stress responses. Adaptive protection operates in terms of DNA damage prevention and repair, and of immune stimulation. It develops with a delay of hours, may last for days to months, and increasingly disappears at doses beyond about 100 to 200 mGy. Radiation-induced apoptosis and terminal cell differentiation occurs also at higher doses and adds to protection by reducing genomic instability and the number of mutated cells in tissues. At low doses, damage reduction by adaptive protection against damage from endogenous sources predictably outweighs radiogenic damage induction. The analysis of the consequences of the particular low-dose scenario shows that the linear-no-threshold (LNT) hypothesis for cancer risk is scientifically unfounded and appears to be invalid in favor of a threshold or hormesis. This is consistent with data both from animal studies and human epidemiological observations on low-dose induced cancer. The LNT hypothesis should be abandoned and be replaced by a hypothesis that is scientifically justified. The appropriate model should include terms for both linear and non-linear response probabilities. Maintaining the LNT-hypothesis as basis for radiation protection causes unressonable fear and expenses. (author)

  4. Effect of radiation on Poly Vinyl chloride (PVC)

    International Nuclear Information System (INIS)

    Massaud, F.; Haraga, S.; Benfaid, N.; Benayad, S.; Kabar, Y.; Elmesmary, Y; Elwerfeli, M.; Omran, Sh.

    1993-01-01

    Radiation crosslinking of polymeric materials is of increasing commercial importance because of the improved thermal, electrical and mechanical properties. Poly Vinylchloride (PVC) is one of the most important polymers. Many attempts were made to study the primary reactions induced by the direct effect of radiation on PVC. In this study, powder PVC was irradiated with different doses at ambient temperature. Formation of free radicals was investigated by electron spin resonance (ESR) method and molecular weight was determined by viscosity measurements. It has been observed that hydrogen chloride was evolved because of noticeable change in color. One type of radical, Poly enyl structure was trapped at room temperature. The non-symmetric singlet structure of the ESR spectra is due to the presence of oxygen. The radical concentration increased with increase of dose. The molecular weight of irradiated PVC was found to be inversely proportional to the increase of radiation dose, which is believed to be due to the occurrence of degradation. It can be concluded that gamma radiation will be the best method for crosslinking of PVC if multi-functional groups or monomers are present. (author)

  5. Measurement of the effect of the lattice pitch on the effective resonance integral of natural uranium

    Energy Technology Data Exchange (ETDEWEB)

    Krcevinac, S; Takac, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1966-04-15

    The present work investigates the dependence of the effective resonance integral on the lattice pitch. Theoretically, the dependence is determined starting from Wigner's rational approximation in which the lattice is characterized by the effective ratio (s/M). Later this allows correlation between the lattice resonance integral and the resonance integral of the single rod (the rod in infinite medium). Using two approximations for Dancoff's factor we give the measured functional dependence of the effective resonance integral on the effective (s/M) ratio. The activation method and the differential technique of measuring absorption distribution in U-238 are used to determine the resonance integral experimentally. Since the effective lattice pitch cannot be defined with certain reliability, due to the use of cadmium in determining the cadmium ratio in the fuel rod, besides other perturbing effects, the method of comparing thermal activations of U-238 and a suitable thermal detector are used to determine the cadmium ratio.

  6. Measurement of the effect of the lattice pitch on the effective resonance integral of natural uranium

    International Nuclear Information System (INIS)

    Krcevinac, S.; Takac, S.

    1966-04-01

    The present work investigates the dependence of the effective resonance integral on the lattice pitch. Theoretically, the dependence is determined starting from Wigner's rational approximation in which the lattice is characterized by the effective ratio (s/M). Later this allows correlation between the lattice resonance integral and the resonance integral of the single rod (the rod in infinite medium). Using two approximations for Dancoff's factor we give the measured functional dependence of the effective resonance integral on the effective (s/M) ratio. The activation method and the differential technique of measuring absorption distribution in U-238 are used to determine the resonance integral experimentally. Since the effective lattice pitch cannot be defined with certain reliability, due to the use of cadmium in determining the cadmium ratio in the fuel rod, besides other perturbing effects, the method of comparing thermal activations of U-238 and a suitable thermal detector are used to determine the cadmium ratio

  7. The radiation effects on the living cell

    International Nuclear Information System (INIS)

    Sage, E.; Dutrillaux, B.; Soussi, Th.; Boiteux, S.; Lopez, B.; Feunteun, J.

    1999-06-01

    This publication is a presentation of particular points discussed during the colloquium of the 15-18 june 1999, for which scientific researches are performed at the CEA/CNRS. They deal with the radiobiology, for the radiation effects on living matter; with the DNA, for the knowledge and repair mechanisms on cells submitted to ionizing radiations; with the exposition to UV in correlation with neoplasms; with the P53 gene which is a tumour suppressor. (A.L.B.)

  8. Genetic effects of radiation. Annex I

    International Nuclear Information System (INIS)

    1982-01-01

    This Annex is aimed at an updating of the 1977 UNSCEAR report, which presented a detailed review of the genetic effects of ionizing radiation, especially those parts that require significant revisions in the light of new data. There is an extensive bibliography with over 1000 references. Particular emphasis is given to those data that are relevant to the evaluation of genetic radiation hazards in man.

  9. Biological effect of radiation on human

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yun Sil; Cho, Chul Koo; Lee, Su Jae [and others

    2000-04-01

    1. Adaptive response when 0.01 Gy was preirradiated before high challenging dose is induced in normal cell types such normal lymphocytes, primary keratinocytes, and L929 fibroblast cells but not in neoplastic cells such as L5178Y lymphoma cells, EL-4 lymphoma cells and 308 papilloma cells. 2. Heat shock protein (HSP) 25 and inducible HSP70 is responsible for the induction of adaptive response and radioresistance - cell cycle regulation, antiapoptotic molecule and PKC activation were involved. 3. Apoptosis was induced at most 5. hrs after irradiation in primary keratinocytes, in v-rasHa transformed keratinocytes, the maximum interval was 16 hrs, and in 308 papilloma cells, the maximum was 48 hrs. 4. PKC response by radiation is correlated with induction of apoptosis. 5. Rapid induction PKCdelta in primary keratinocytes and no response of PKC epsilon may involved in radiation induced apoptosis. 6. The rate of resorption was increased when radiation was given at 2.5 days after gestation. Early death including foetal death were highly expressed when radiation was given at 7.5 days after gestation. There are no difference in incidence of late death including embryonic death. 7. 2 Gy is the most effective dose in radiation induced teratogenesis in mouse model. 8. Growth retardation and small head was present when radiation was given at 5.5, 7.5, 11.5 and 15.5 days after gestation and small head showed high incidence at 11.5 days after gestation. 9. External malformation, internal malformation and skeletal malformation was induced when radiation was given at 7.5 days after gestation. 10. OGG1-mutated cells induced radiosensitive by G2/M cell cycle arrest. 11. Radiation induced G2/M phase cell cycle and correlated with radiosensitivity. 12. PKCalpha induced differentiation. 13. Radiation exposed cells showed carcinogenic effect. 14. Organ specific radiosensitivity was shown and protein expression was involved.

  10. Biological effect of radiation on human

    International Nuclear Information System (INIS)

    Lee, Yun Sil; Cho, Chul Koo; Lee, Su Jae

    2000-04-01

    1. Adaptive response when 0.01 Gy was preirradiated before high challenging dose is induced in normal cell types such normal lymphocytes, primary keratinocytes, and L929 fibroblast cells but not in neoplastic cells such as L5178Y lymphoma cells, EL-4 lymphoma cells and 308 papilloma cells. 2. Heat shock protein (HSP) 25 and inducible HSP70 is responsible for the induction of adaptive response and radioresistance - cell cycle regulation, antiapoptotic molecule and PKC activation were involved. 3. Apoptosis was induced at most 5. hrs after irradiation in primary keratinocytes, in v-rasHa transformed keratinocytes, the maximum interval was 16 hrs, and in 308 papilloma cells, the maximum was 48 hrs. 4. PKC response by radiation is correlated with induction of apoptosis. 5. Rapid induction PKCdelta in primary keratinocytes and no response of PKC epsilon may involved in radiation induced apoptosis. 6. The rate of resorption was increased when radiation was given at 2.5 days after gestation. Early death including foetal death were highly expressed when radiation was given at 7.5 days after gestation. There are no difference in incidence of late death including embryonic death. 7. 2 Gy is the most effective dose in radiation induced teratogenesis in mouse model. 8. Growth retardation and small head was present when radiation was given at 5.5, 7.5, 11.5 and 15.5 days after gestation and small head showed high incidence at 11.5 days after gestation. 9. External malformation, internal malformation and skeletal malformation was induced when radiation was given at 7.5 days after gestation. 10. OGG1-mutated cells induced radiosensitive by G2/M cell cycle arrest. 11. Radiation induced G2/M phase cell cycle and correlated with radiosensitivity. 12. PKCalpha induced differentiation. 13. Radiation exposed cells showed carcinogenic effect. 14. Organ specific radiosensitivity was shown and protein expression was involved

  11. Radiation effects in corundum monocrystal

    International Nuclear Information System (INIS)

    Soulayman, S.; Attiah, J.; Molhem, A. G.

    2007-01-01

    It is found by this work that the irradiation of corundum monocrystals by energetic particles creates stable lattice defects, as a result of the atomic displacements to the sublattice. We have identified the colour centers (F and F + ) and more complex ones line [Al i + F]. This finding is in an agreement with the experimental results, available in the literature. We have also investigated the mechanism of occurrence of, so called 'radiation memory' in corundum monocrystals. This phenomenon reflects the fact that, after irradiation and annealing at high temperature and irradiation again by the quanta of x-rays, the absorption line 302 nm (4.1 eV) in the spectrum of optical absorption is restored in the range 200-650 nm. A comparison of our results with the results of other researchers in carried out. (author)

  12. Additive effects of ultraviolet radiation

    International Nuclear Information System (INIS)

    Cullen, A.P.

    1980-01-01

    A xenon-mercury high pressure lamp and a double monochromator were used to produce ultraviolet (uv) radiation at 295 nm. Pigmented rabbit eyes were irradiated and evaluated by slitlamp biomicroscopy. Corneal threshold (Hc) was 0.05 J.cm-2 and lens threshold (hL) was 0.75 J.cm-2. Other eyes were irradiated with 2 Hc and evaluated from 4 to 24 h at 4 h intervals. Corneal damage was only greater than that expected from a single Hc exposure if the separation between the two Hc exposures did not exceed 8 h. The most repeatable and reliable corneal response to these levels of uv was the development of corneal epithelial granules

  13. Size effect in radiation damage

    International Nuclear Information System (INIS)

    Brumovsky, M.

    1979-01-01

    Radiation embrittlement of nuclear reactor pressure vessel steels is mostly measured using small standard specimens in dynamic bend tests. Their dimensions are much smaller than those of the reactor. The increase in the critical temperature (transition temperature from the brittle-to-ductile fracture) is normally measured using standard Charpy-V type specimens or small CT-type specimens. This increase is then used as the main parameter for the pressure vessel safety evaluation. The philosophy of experiments is discussed used for the nonirradiated and irradiated pressure vessel steels. A comparison of the increase in the transition temperature measured in different types of specimens using various testing methods (static and dynamic bend tests with notch or crack) is also made. The results of this comparison and another study showed a relatively good agreement. (author)

  14. Temperature Dependence of the Resonant Magnetoelectric Effect in Layered Heterostructures

    Directory of Open Access Journals (Sweden)

    Dmitrii A. Burdin

    2017-10-01

    Full Text Available The dependence of the resonant direct magnetoelectric effect on temperature is studied experimentally in planar composite structures. Samples of rectangular shapes with dimensions of 5 mm × 20 mm employed ferromagnetic layers of either an amorphous (metallic glass alloy or nickel with a thickness of 20–200 μm and piezoelectric layers of single crystalline langatate material or lead zirconate titanate piezoelectric ceramics with a thickness of 500 μm. The temperature of the samples was varied in a range between 120 and 390 K by blowing a gaseous nitrogen stream around them. It is shown that the effective characteristics of the magnetoelectric effect—such as the mechanical resonance frequency fr, the quality factor Q and the magnitude of the magnetoelectric coefficient αE at the resonance frequency—are contingent on temperature. The interrelations between the temperature changes of the characteristics of the magnetoelectric effect and the temperature variations of the following material parameters—Young’s modulus Y, the acoustic quality factor of individual layers, the dielectric constant ε, the piezoelectric modulus d of the piezoelectric layer as well as the piezomagnetic coefficients λ(n of the ferromagnetic layer—are established. The effect of temperature on the characteristics of the nonlinear magnetoelectric effect is observed for the first time. The results can be useful for designing magnetoelectric heterostructures with specified temperature characteristics, in particular, for the development of thermally stabilized magnetoelectric devices.

  15. Radiation Effects on Spacecraft Structural Materials

    International Nuclear Information System (INIS)

    Wang, Jy-An J.; Ellis, Ronald J.; Hunter, Hamilton T.; Singleterry, Robert C. Jr.

    2002-01-01

    Research is being conducted to develop an integrated technology for the prediction of aging behavior for space structural materials during service. This research will utilize state-of-the-art radiation experimental apparatus and analysis, updated codes and databases, and integrated mechanical and radiation testing techniques to investigate the suitability of numerous current and potential spacecraft structural materials. Also included are the effects on structural materials in surface modules and planetary landing craft, with or without fission power supplies. Spacecraft structural materials would also be in hostile radiation environments on the surface of the moon and planets without appreciable atmospheres and moons around planets with large intense magnetic and radiation fields (such as the Jovian moons). The effects of extreme temperature cycles in such locations compounds the effects of radiation on structural materials. This paper describes the integrated methodology in detail and shows that it will provide a significant technological advance for designing advanced spacecraft. This methodology will also allow for the development of advanced spacecraft materials through the understanding of the underlying mechanisms of material degradation in the space radiation environment. Thus, this technology holds a promise for revolutionary advances in material damage prediction and protection of space structural components as, for example, in the development of guidelines for managing surveillance programs regarding the integrity of spacecraft components, and the safety of the aging spacecraft. (authors)

  16. Medical exposure and the effects of radiation

    International Nuclear Information System (INIS)

    Okuyama, Chio

    2011-01-01

    Radiation gives cracks to genes. The influence is divided into deterministic effect with a threshold value, and the stochastic effect (tumor and genetic effect) which increases according to the exposure amount. Although we are put to various non-artificial radiations, which we cannot be avoided, on the earth, the contamination by artificial radiation can be defended. Artificial radioactive exposure includes medical exposure and non-medical exposure for example by nuclear power plant. As to medical examinations using radiation, the inquiry about the radiation exposure is increasing after the occurrence of the first nuclear power plant disaster of Fukushima. While concern about non-medical radioactive exposure increases, the uneasiness to medical irradiation is also increasing. The dose limit by artificial radioactive exposure other than medical exposure is set up in order to prevent the influence on the health. While the dose limit of the public exposure is set to the lower value than the total dose of non-artificial exposure concerning of a safety margin for all people, the dose limit of medical exposure is not defined, since it is thought that medical irradiation has a benefit for those who receive irradiation. Making an effort to decrease the radiation dose in performing the best medical treatment is the responsibility with which we are burdened. (author)

  17. Radiation effects concerns at a spallation source

    International Nuclear Information System (INIS)

    Sommer, W.F.

    1990-01-01

    Materials used at spallation neutron sources are exposed to energetic particle and photon radiation. Mechanical and physical properties of these materials are altered; radiation damage on the atomic scale leads to radiation effects on the macroscopic scale. Most notable among mechanical-property radiation effects in metals and metal alloys are changes in tensile strength and ductility, changes in rupture strength, dimensional stability and volumetric swelling, and dimensional changes due to stress-induced creep. Physical properties such as electrical resistivity also are altered. The fission-reactor community has accumulated a good deal of data on material radiation effects. However, when the incident particle energy exceeds 50 MeV or so, a new form of radiation damage ensues; spallation reactions lead to more energetic atom recoils and the subsequent temporal and spatial distribution of point defects is much different from that due to a fission-reactor environment. In addition, spallation reactions cause atomic transmutations with these new atoms representing an impurity in the metal. The higher-energy case is of interest at spallation sources; limited detailed data exist for material performance in this environment. 35 refs., 13 figs., 1 tab

  18. Topological magnetoelectric effects in microwave far-field radiation

    Energy Technology Data Exchange (ETDEWEB)

    Berezin, M.; Kamenetskii, E. O.; Shavit, R. [Microwave Magnetic Laboratory, Department of Electrical and Computer Engineering, Ben Gurion University of the Negev, Beer Sheva (Israel)

    2016-07-21

    Similar to electromagnetism, described by the Maxwell equations, the physics of magnetoelectric (ME) phenomena deals with the fundamental problem of the relationship between electric and magnetic fields. Despite a formal resemblance between the two notions, they concern effects of different natures. In general, ME-coupling effects manifest in numerous macroscopic phenomena in solids with space and time symmetry breakings. Recently, it was shown that the near fields in the proximity of a small ferrite particle with magnetic-dipolar-mode (MDM) oscillations have the space and time symmetry breakings and the topological properties of these fields are different from the topological properties of the free-space electromagnetic fields. Such MDM-originated fields—called magnetoelectric (ME) fields—carry both spin and orbital angular momenta. They are characterized by power-flow vortices and non-zero helicity. In this paper, we report on observation of the topological ME effects in far-field microwave radiation based on a small microwave antenna with a MDM ferrite resonator. We show that the microwave far-field radiation can be manifested with a torsion structure where an angle between the electric and magnetic field vectors varies. We discuss the question on observation of the regions of localized ME energy in far-field microwave radiation.

  19. Numerical investigation of radiative properties and surface plasmon resonance of silver nanorod dimers on a substrate

    International Nuclear Information System (INIS)

    An, Wei; Zhu, Tong; Zhu, QunZhi

    2014-01-01

    When the distance between two silver nanoparticles is small enough, interparticle surface plasmon coupling has a great impact on their radiative properties. It is becoming a promising technique to use in the sensing and imaging. A model based on finite difference time domain method is developed to investigate the effect of the assembled parameters on the radiative properties and the field-enhancement effect of silver nanorod dimer. The numerical results indicate that the radiative properties of silver nanorod dimer are very sensitive to the assembled angle and the polarization orientation of incident wave. There is great difference on the intensity and location of field-enhancement effect for the cases of different assembled angle and polarization. The most intensive field-enhancement effect occurs in the middle of two nanorods when two nanorods is assembled head to head and the polarization orientation parallels to the length axis of nanorods. Moreover, compared with the single nanorod, the wavelength of extinction peak of dimer has a red-shift, and the intensity of field-enhancement effect on the dimer is more intensive than that of single particle. With the increasing of particle length, extinction cross-section of silver nanorod dimer rises, while extinction efficiency and scattering efficiency firstly increase then drop down gradually. In addition, the extinction peaks of silver nanorod dimer on the substrate are smaller than that without the substrate, and their extinction peaks has a red-shift compared with that without the substrate. -- Highlights: ► Radiative properties of silver nanorod dimer are very sensitive to the assembled angle. ► The projective length of nanorod dimer on the polarization orientation is crucial. ► Compared with single nanorod, wavelength of extinction peak of dimer has a red-shift. ► Extinction peaks of dimer on the substrate are smaller than that without the substrate

  20. Radiation effects in LDD MOS devices

    International Nuclear Information System (INIS)

    Woodruff, R.L.; Adams, J.R.

    1987-01-01

    The purpose of this work is to investigate the response of lightly doped drain (LDD) n-channel transistors to ionizing radiation. Transistors were fabricated with conventional (non-LDD) and lightly doped drain (LDD) structures using both standard (non-hardened) and radiation hardened gate oxides. Characterization of the transistors began with a correlation of the total-dose effects due to 10 keV x-rays with Co-60 gamma rays. The authors find that for the gate oxides and transistor structures investigated in this work, 10 keV x-rays produce more fixed-charge guild-up in the gate oxide, and more interface charge than do Co-60 gamma rays. They determined that the radiation response of LDD transistors is similar to that of conventional (non-LDD) transistors. In addition, both standard and radiation-hardened transistors subjected to hot carrier stress before irradiation show a similar radiation response. After exposure to 1.0 x 10 6 rads(Si), non-hardened transistors show increased susceptibility to hot-carrier graduation, while the radiation-hardened transistors exhibit similar hot-carrier degradation to non-irradiated devices. The authors have demonstrated a fully-integrated radiation hardened process tht is solid to 1.0 x 10 6 rads(Si), and shows promise for achieving 1.0 x 10 7 rad(Si) total-dose capability

  1. Resonant scattering on impurities in the quantum Hall effect

    International Nuclear Information System (INIS)

    Gurvitz, A.

    1994-06-01

    We developed a new approach to carrier transport between the edge states via resonant scattering on impurities, which is applicable both for short and long range impurities. A detailed analysis of resonant scattering on a single impurity is performed. The results used for study of the inter-edge transport by multiple resonant hopping via different impurities' site. We found the total conductance can be obtained from an effective Schroedinger equation with constant diagonal matrix elements in the Hamiltonian, where the complex non-diagonal matrix elements are the amplitudes of a carrier hopping between different impurities. It is explicitly shown how the complex phase leads to Aharonov-Bohm oscillations in the total conductance. Neglecting the contribution of self-crossing resonant-percolation trajectories, we found that the inter-edge carrier transport is similar to propagation in one-dimensional system with off-diagonal disorder. Then we demonstrated that each Landau band has an extended state Ε Ν , while all other states are localized, and the localization length behaves as L - 1 Ν (Ε) ∼ (Ε - Ε Ν ) 2 . (author)

  2. Solar Radiation effect on the bituminous binder

    International Nuclear Information System (INIS)

    Tadeo Rico, A.; Torres Perez, A.

    2010-01-01

    Asphalt, used as binder in road construction, becomes more brittle and harder during working life on the surface of the road pavement, conducting toward their deterioration. This is caused by the oxidation of the molecular functional groups of the asphalt molecular structure. Moreover, it is observed that ultraviolet radiation increases the oxidation process. However, the effect of solar light on the asphalt degradation has been poorly researched. The aim of this work is to study asphalt ageing caused by effect of solar radiation, by using standard test. Four commercial asphalts from different companies were selected: two with penetration number 50/70, and the other two polymer modified asphalts. From each of the asphalts forty samples were taken off and placed in four different aging conditions of temperature and radiation for a period ranging from 40 to 500 days. Ring and Ball test, and Fraass breaking Point test, were used to analyse the changes of asphalt properties after exposition to solar radiation. The results of the four analyzed asphalts showed a distinct behaviour; not only in the test temperature increase but also in the rate. Another experiment was carried out. Samples from a hot mix asphalt batch were placed under solar radiation, and were compacted by the Marshall procedure after increasing periods of time. Density and resistance to plastic flow using Marshall Apparatus were measured. Results showed an increase in the stability of samples under radiation. Both experiments show that the solar radiation is enough to cause changes in the asphalt molecular structure due to oxidation. So that, the study of the effect of the solar radiation on the asphalt properties could be a good tool to asses the performances of asphalt pavement. (Author) 26 refs.

  3. Effects of radiation on aquatic organisms

    International Nuclear Information System (INIS)

    Kaur, Harbhajan; Lata, Poonam; Sharma, Ankush

    2012-01-01

    With the onset of nuclear age, nuclear fuel cycle products, nuclear medicine techniques, disposal of radio active wastes on land or in water, fall out of testing nuclear weapons has contributed large amount of radio nuclides to the water bodies. Radio nuclides can imbalance aquatic ecosystem resulting in danger to natural life. The biological effects of radiation on aquatic life are mortality, pathophysiological, reproductive, developmental and genetic changes. A broad review of the results obtained about the aquatic organisms related to different phyla indicates that the lower or less developed or more primitive organisms are more resistant than the higher or more advanced, developed and complex organisms to ionizing radiation. The algae, protozoa are more resistant than the insects, crustaceans, molluscs and fishes. The changes in sensitivity between different stages of development have also been noted. A review of the results of exposing salmonoid gametes, eggs, fingerlings and adults to X-rays supports the concepts that radio sensitivity decreases with age. This paper presents a selective review on effects of radiation and radio nuclides on the aquatic life. It include uses and sources of radiation, effective quantity of radiation, lethal and sub lethal effect, effects on survival, growth, reproduction, behaviour, metabolism, carcinogenicity and mutagenicity. (author)

  4. Principles and techniques of radiation hardening. Volume 2. Transient radiation effects in electronics (TREE)

    International Nuclear Information System (INIS)

    Rudie, N.J.

    1976-01-01

    The three-volume book is intended to serve as a review of the effects of thermonuclear explosion induced radiation (x-rays, gamma rays, and beta particles) and the resulting electromagnetic pulse (EMP). Volume 2 deals with the following topics: radiation effects on quartz crystals, tantalum capacitors, bipolar semiconductor devices and integrated circuits, field effect transistors, and miscellaneous electronic devices; hardening electronic systems to photon and neutron radiation; nuclear radiation source and/or effects simulation techniques; and radiation dosimetry

  5. Optical Spring Effect in Micro-Bubble Resonators and Its Application for the Effective Mass Measurement of Optomechanical Resonant Mode

    OpenAIRE

    Zhenmin Chen; Xiang Wu; Liying Liu; Lei Xu

    2017-01-01

    In this work, we present a novel approach for obtaining the effective mass of mechanical vibration mode in micro-bubble resonators (MBRs). To be specific, the effective mass is deduced from the measurement of optical spring effect (OSE) in MBRs. This approach is demonstrated and applied to analyze the effective mass of hollow MBRs and liquid-filled MBRs, respectively. It is found that the liquid-filled MBRs has significantly stronger OSE and a less effective mass than hollow MBRs, both of the...

  6. RF slice profile effects in magnetic resonance fingerprinting.

    Science.gov (United States)

    Hong, Taehwa; Han, Dongyeob; Kim, Min-Oh; Kim, Dong-Hyun

    2017-09-01

    The radio frequency (RF) slice profile effects on T1 and T2 estimation in magnetic resonance fingerprinting (MRF) are investigated with respect to time-bandwidth product (TBW), flip angle (FA) level and field inhomogeneities. Signal evolutions are generated incorporating the non-ideal slice selective excitation process using Bloch simulation and matched to the original dictionary with and without the non-ideal slice profile taken into account. For validation, phantom and in vivo experiments are performed at 3T. Both simulations and experiments results show that T1 and T2 error from non-ideal slice profile increases with increasing FA level, off-resonance, and low TBW values. Therefore, RF slice profile effects should be compensated for accurate determination of the MR parameters. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. A Faraday effect position sensor for interventional magnetic resonance imaging.

    Science.gov (United States)

    Bock, M; Umathum, R; Sikora, J; Brenner, S; Aguor, E N; Semmler, W

    2006-02-21

    An optical sensor is presented which determines the position and one degree of orientation within a magnetic resonance tomograph. The sensor utilizes the Faraday effect to measure the local magnetic field, which is modulated by switching additional linear magnetic fields, the gradients. Existing methods for instrument localization during an interventional MR procedure often use electrically conducting structures at the instruments that can heat up excessively during MRI and are thus a significant danger for the patient. The proposed optical Faraday effect position sensor consists of non-magnetic and electrically non-conducting components only so that heating is avoided and the sensor could be applied safely even within the human body. With a non-magnetic prototype set-up, experiments were performed to demonstrate the possibility of measuring both the localization and the orientation in a magnetic resonance tomograph. In a 30 mT m(-1) gradient field, a localization uncertainty of 1.5 cm could be achieved.

  8. Health effects of low level radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, Sadao [Central Research Inst. of Electric Power Industry, Tokyo (Japan)

    1998-12-31

    In 1982, Prof. Thomas Don Luckey of Missouri Univ. asserted `Radiation Hormesis` on the Journal of Health Physics and he published two books. CRIEPI initiated the research program on Radiation Hormesis following his assertion to confirm `is it true or not?` After nearly ten year research activities on data surveys and animal tests with many Universities, we are realizing scientific truth of bio-positive effects by low level radiation exposures. The interesting bio-positive effects we found could be categorized in following five groups. 1) Rejuvenation of cells such as increase of SOD and cell membrane permeability, 2) Moderation of psychological stress through response of key enzymes, 3) Suppression and therapy of adult-diseases such as diabetes and hypertension, 4) Suppression of cancer through enhancement of immune systems such as lymphocytes, 5) Suppression of cancer and ratio-adaptive response by activation of DNA repair and apoptosis. In the responses of many specialists to our initiation of radiation hormesis research program following T.D. Luckey`s claim about low level radiation, I have to pick up for the first, the great success of Prof. Sakamoto. Prof. Sakamoto had been already applying whole body low dose irradiation for ten years before our radiation hormesis research started on the therapy to suppress the cancer reappearing after treatment. He reported about his successful trial to real patients and showed an enhancement of immune system. (author)

  9. Health effects of low level radiation

    International Nuclear Information System (INIS)

    Hattori, Sadao

    1998-01-01

    In 1982, Prof. Thomas Don Luckey of Missouri Univ. asserted 'Radiation Hormesis' on the Journal of Health Physics and he published two books. CRIEPI initiated the research program on Radiation Hormesis following his assertion to confirm 'is it true or not?' After nearly ten year research activities on data surveys and animal tests with many Universities, we are realizing scientific truth of bio-positive effects by low level radiation exposures. The interesting bio-positive effects we found could be categorized in following five groups. 1) Rejuvenation of cells such as increase of SOD and cell membrane permeability, 2) Moderation of psychological stress through response of key enzymes, 3) Suppression and therapy of adult-diseases such as diabetes and hypertension, 4) Suppression of cancer through enhancement of immune systems such as lymphocytes, 5) Suppression of cancer and ratio-adaptive response by activation of DNA repair and apoptosis. In the responses of many specialists to our initiation of radiation hormesis research program following T.D. Luckey's claim about low level radiation, I have to pick up for the first, the great success of Prof. Sakamoto. Prof. Sakamoto had been already applying whole body low dose irradiation for ten years before our radiation hormesis research started on the therapy to suppress the cancer reappearing after treatment. He reported about his successful trial to real patients and showed an enhancement of immune system. (author)

  10. Radiation effects on bovine taste bud membranes

    International Nuclear Information System (INIS)

    Shatzman, A.R.; Mossman, K.L.

    1982-01-01

    In order to investigate the mechanisms of radiation-induced taste loss, the effects of radiation on preparations of enriched bovine taste bud membranes were studied. Taste buds containing circumvallate papilae, and surrounding control epithelial tissues devoid of taste buds, were obtained from steers and given radiation doses of 0-7000 cGy (rad). Tissue fractions were isolated into membrane-enriched and heterogeneous components using differential and sucrose gradient centrifugation of tissue homogenates. The yield of membranes, as measured by protein content in the buoyant membrane-enriched fractions, was reduced in quantity with increasing radiation dose. The relation between radiation dose and membrane quantity in membrane-enriched fractions could be fit by a simple exponential model with taste bud-derived membranes twice as radiosensitive as membranes from control epithelial tissue. Binding of sucrose, sodium, and acetate and fluoride stimulation of adenylate cyclase were nearly identical in both irradiated and nonirradiated intact membranes. Radiation had no effect on fractions of heterogeneous components. While it is not clear what changes are occurring in enriched taste cell membranes, damage to membranes may play an important role in the taste loss observed in patients following radiotherapy

  11. Effects of ionizing radiation on bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Suhadi, F [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1976-10-01

    The differences of radiosensitivities among bacteria in addition to the dependence upon the species or strains also depends on the environmental condition during irradiation (temperature, medium, the presence of protective or sensitizing agents, the gas phase or atmosphere, and water activity, or degree of hydration) and on the effects of the environmental condition before and after irradiation treatment (temperature of incubation, age of culture and growth medium). In general, spores are more resistant to radiation than vegetatic bacteria, with the exception that a few cocci are the most radiation resistant bacteria (Micrococcus and Streptococcus). The application of ionizing radiation in the fields of microbiology supports the radiation sterilization of medical and pharmaceutical products. In addition, microbiological aspects of food preservation, especially radurization, radicidation, and immunization studies by using irradiated microorganisms, are also important.

  12. Electromagnetic and radiation environments: effects on pacemakers

    International Nuclear Information System (INIS)

    Mouton, J.; Trochet, R.; Vicrey, J.; Sauvage, M.; Chauvenet, B.; Ostrovski, A.; Leroy, E.; Haug, R.; Dodinot, B.; Joffre, F.

    1999-01-01

    Nowadays, medical care development allows many people to share the benefits of implanted pacemakers (PM). PM can be perturbed and even fall in complete breakdowns in an electromagnetic and radiation environment. A stimuli-dependent patient can thus be seriously in danger. This article presents the effect of ionizing radiation from either a cobalt-60 source or from a linear accelerator (Saturne 43) on 12 pacemakers. It seems that technological progress make electronic circuits more sensitive to the cumulated dose of radiation. This survey shows that pacemakers have great difficulties to sustain ionizing radiation doses that are commonly delivered to patients during therapies. Usually perturbed functioning appears suddenly and means a strong shift of stimuli that might lead to heart failure

  13. Effect of radiation processing on meat tenderisation

    Science.gov (United States)

    Kanatt, Sweetie R.; Chawla, S. P.; Sharma, Arun

    2015-06-01

    The effect of radiation processing (0, 2.5, 5 and 10 kGy) on the tenderness of three types of popularly consumed meat in India namely chicken, lamb and buffalo was investigated. In irradiated meat samples dose dependant reduction in water holding capacity, cooking yield and shear force was observed. Reduction in shear force upon radiation processing was more pronounced in buffalo meat. Protein and collagen solubility as well as TCA soluble protein content increased on irradiation. Radiation processing of meat samples resulted in some change in colour of meat. Results suggested that irradiation leads to dose dependant tenderization of meat. Radiation processing of meat at a dose of 2.5 kGy improved its texture and had acceptable odour.

  14. The toxic effects of ionizing radiations

    International Nuclear Information System (INIS)

    Draghita Payet, A.C.

    2006-06-01

    The sources of radiations to which the human body is subjected are of natural or artificial origin and the irradiation of the human body can take place either by internal or external way. The ionizing radiations act at several levels of the human body, the main thing being the molecule of DNA. The ionizing radiations have no specificity, the effects on the human body can be: somatic, genetic or hereditary, teratogen. In the case of a human being irradiation, we proceed to the diagnosis and to the treatment of the irradiated person, however, to decrease the incidence of injuries we use the radiation protection. The treatment if necessary will be established according to the irradiation type. (N.C.)

  15. Monte Carlo calculations of resonance radiative transfer through a semi-infinite atmosphere

    International Nuclear Information System (INIS)

    Slater, G.; Salpeter, E.E.; Wasserman, I.

    1982-01-01

    The results of Monte Carlo calculations of radiative transfer through a semi-infinite plane-parallel atmosphere of resonant scatterers are presented. With a photon source at optical depth tau/sub ES/ we model the semi-infinite geometry by embedding a perfectly reflecting mirror at depth tau/sub MS/+tau/sub ES/. Although some quantities characterizing the emergent photons diverge as tau/sub MS/→infinity, the mean number of scatters, N/sub ES/, and path length, L/sub ES/, accumulated between the source and the edge of the atmosphere converge. Accurate results of N/sub ES/, L/sub ES/, X/sub pk/, the most probable frequency shift of the escaping photons, and tau/sub LAST/, the mean optical depth at which they last scatter, are obtained by choosing tau/sub MS/ = 4tau/sub ES/. Approximate analytic calculations of N/sub ES/, L/sub ES/, N, the mean total number of scatters undergone by escaping photons, L, their mean total path length, and , their mean (absolute) frequency shift, are presented for a symmetric slab with αtau/sub ES/>>1 and tau/sub MS/>>tau/sub ES/. Analogous calculations for an asymmetric slab are discussed. Analytic fitting formulae for N/sub ES/, L/sub ES/, X/sub pk/, and tau/sub LAST/ are given

  16. Study of the ionization of sodium vapor in the presence of resonant laser radiation

    International Nuclear Information System (INIS)

    Carre, B.

    1986-06-01

    Ionization of a diffuse sodium jet, excited by laser radiation (D2 resonance), either continuous or pulsed, is studied by electron spectroscopy. Results show: associative ionization (AI) in the collision of two Na(3p) excited atoms; occupancy of highly excited nl states in energy association collisions of two Na(3p) followed by Penning collisional ionization (CI) in the system Na(nl) + Na(3p); heating of electrons by 1, 2, or 3 superelastic collisions with Na(3p). For both the excitation cases (continuous or pulsed source) analysis of experiment results leads to a description of the whole of the ionized medium, characterized as being low density and the site of the ambipolar diffusion of charged particles. A highly simplified model describes the kinetic and electrokinetic equilibrium (continuous case) in which the different populations of distinct nonthermalized energy (low energy primary electrons, hot electrons) play specific roles. The cross sections associated with AI and CI are estimated from experiment results using the model [fr

  17. The fate of allogenic radiation sterilized bone grafts controlled by the electron spin resonance spectrometry

    International Nuclear Information System (INIS)

    Ostrowski, K.; Dziedzic-Goclawska, A.

    1981-01-01

    The normal fate of bone grafts is their resorption and substitution by the own host's bone tissue. This phenomenon described as creeping substitution process was controlled using biopsies from the grafted region in allogenic experimental system. Electron spin resonance (ESR) spectrometry was used for independent evaluation of resorption and substitution processes. The measurements were based on the process of induction in the hydroxyapatite (HA) crystals of bone mineral of stable paramagnetic centers which can be detected by ESR spectrometry. The loss of total amount of spins connected with the paramagnetic centers expressed in percent describes the kinetics of resorption. The changes in the concentration of spins due to the ''dilution'' of spins implanted with the graft by the nonirradiated ingrowing host's own bone describe the kinetics of the substitution process. Allogenic bone of calvaria was grafted orthotopically into rabbits after lyophilization and radiation sterilization with a dose of 3.5 Mrads. The process of graft's rebuilding was evaluated using the described ESR method. The application of the described technique in the human clinic is possible. (author)

  18. High Radiation Doses from Radiotherapy Measured by Electron Spin Resonance in Dental Enamel

    International Nuclear Information System (INIS)

    Pass, B.; Wood, R.E.; Liu, F.; McLean, M.; Aldrich, J.E.

    1998-01-01

    For radiotherapy, an error in the complicated treatment planning or treatment procedure is a possibility, however remote. Thus, in the present study electron spin resonance (ESR) in dental enamel was investigated for the first time as a means of retrospective dosimetry for validating applied radiotherapy doses to the head and neck regions. Total absorbed radiation doses measured by ESR in dental enamel were compared to the doses determined by treatment planning for 19 patients who received radiotherapy for intra-oral, pharyngeal or laryngeal malignancies, or total-body irradiation prior to bone marrow transplants (BMT). For the 15 tumour irradiations there was, within the framework of the tooth positions as presented, general agreement between the treatment planned and ESR dose determinations. There were, however, both significant and minor discrepancies. For the BMT patients there were major discrepancies for two of the four patients investigated. This study indicates that ESR in dental enamel may be useful as the only means of retrospective dosimetry for validating applied radiotherapy doses after treatment. However, further research must be carried out before this technique can be accepted as accurate and reliable. (author)

  19. Effects of radiation on the skin

    International Nuclear Information System (INIS)

    Hopewell, J.W.

    1985-01-01

    The effects of X-irradiation on pig skin are described, comparing and contrasting the effects seen in human and rodent skin. It is concluded that, anatomically, pig skin is the best animal model for human skin. The applications of the 'pig skin model' to investigations of the problems of radiation therapy and radiological protection of human skin are discussed. (U.K.)

  20. Radiation dose effects, hardening of electronic components

    International Nuclear Information System (INIS)

    Dupont-Nivet, E.

    1991-01-01

    This course reviews the mechanism of interaction between ionizing radiation and a silicon oxide type dielectric, in particular the effect of electron-hole pairs creation in the material. Then effects of cumulated dose on electronic components and especially in MOS technology are examined. Finally methods hardening of these components are exposed. 93 refs

  1. Cardiovascular effects of radiation therapy

    International Nuclear Information System (INIS)

    Alvarez, Jose A.G.; Leiva, Gustavo

    2001-01-01

    Therapeutic mediastinal irradiation can induce heart disease with variable degree of cardiac engagement. Heart disease manifestations depend on the grade of involvement of the different cardiac structures. During the first two years following irradiation, pericarditis with or without pericardial effusion is the most common manifestation of toxicity related to radiation therapy. Later on, after a latency period of five to ten years, a constrictive pericarditis may develop. Other type of late cardiac toxicities due to irradiation are restrictive cardiomyopathy, multiple valvular disease, coronary artery disease and different atrioventricular conduction disturbances. The therapeutic approach to this kind of heart disease has to be focused on its progressive course and in the possibility of a global involvement of all the cardiac structures. Pericardiectomy is strongly recommended for recurrent pericardial effusion with cardiac tamponade. Cardiac surgery for myocardial revascularization or valvular disease can be performed with variable results; the presence of myocardial fibrosis can significantly affect perioperative management and long-term results. Cardiac transplantation is a promissory option for those patients with end-stage cardiac failure. Immunosuppressive regimens are not associated with recurrence of malignancy. (author) [es

  2. Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory

    International Nuclear Information System (INIS)

    SivaRanjan, Uppala; Ramachandran, Ramesh

    2014-01-01

    A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R 2 ) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R 2 experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR

  3. Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    SivaRanjan, Uppala; Ramachandran, Ramesh, E-mail: rramesh@iisermohali.ac.in [Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Manauli, P.O. Box-140306, Mohali, Punjab (India)

    2014-02-07

    A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R{sup 2}) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R{sup 2} experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR.

  4. E2 nuclear resonance effects in pionic and kaonic atoms

    International Nuclear Information System (INIS)

    Batty, C.J.; Biagi, S.F.; Blecher, M.

    1977-09-01

    The attenuation due to the E2 nuclear resonance effect has been measured in hadronic atoms using pions with 111 Cd and 112 Cd, and for kaons with 122 Sn. Energies of the relevant X-ray and γ-ray transitions and of the X-ray cascade intensities have also been measured so as to give a self-consistent set of information. The results are found to be in very good agreement with theoretical calculations. (author)

  5. The effect of compressibility on the Alfven spatial resonance heating

    International Nuclear Information System (INIS)

    Azevedo, C.A.

    1984-01-01

    The effect of compressibility of magnetic field line on the damping rate of Alfven spatial resonance heating for a high beta plasma (Kinetic pressure/magnetic pressure) was analysed, using the ideal MHD (Magnetohydrodynamic) model in cylindrical geometry for a diffuse θ-pinch with conducting wall. The dispersion relation was obtained solving the equation of motion in the plasma and vacuum regions together with boundary conditions. (Author) [pt

  6. Radiation effects, nuclear energy and comparative risks

    International Nuclear Information System (INIS)

    Gopinath, D.V.

    2007-01-01

    Nuclear energy had a promising start as an unlimited, inexpensive and environmentally benign source of energy for electricity generation. However, over the decades its growth was severely retarded due to concerns about its possible detrimental effects on the well-being of mankind and the environment. Since such concerns are essentially due to the gigantic magnitude of radioactivity and ionizing radiations associated with nuclear energy, this article starts with a comprehensive account of effects of the ionizing radiation on living systems. Quantitative description of types of radiation exposure and their varied effects is given. The origin, type and magnitude of mutagenic effects of radiation are described. The concept of radiation risk factors, basis for their evaluation and their currently accepted values are presented. With this background, origin and magnitude of radioactivity and associated ionizing radiations in nuclear reactors are presented and the elaborate measures to contain them are described. It is recognized that notwithstanding all the measures taken in the nuclear industry, certain amount of radiation exposure, however small, is inevitable and the values, based on the experience world over, are presented. Estimated health risk due to such exposures is evaluated. For a comparative analysis, risks in other options of electricity generation such as hydel and fossil-fuelled plants are described. It is seen that on an overall basis, the nuclear option is no more risky than the other commonly employed options, and is in fact, significantly less. Lastly, since every option of electricity generation entails some risk, the case of 'no addition of electricity, and its impact on the society are considered. Based on the analysis of extensive data provided by UNDP on the human development parameters for different countries in the world, it is shown that at least for developing countries, any option of addition of electricity would be far more desirable than the

  7. Ionizing radiation effect on human reproduction

    International Nuclear Information System (INIS)

    Jirous, J.

    1987-01-01

    A review is presented of the existing knowledge on the adverse effects of ionizing radiation on human reproduction. Some interesting findings have been obtained by interapolating the results of studies in mouse embryos to humans, important knowledge has been obtained in studies involving the population of Hiroshima and Nagasaki. The review summarizes the knowledge in the following conclusions: (1) prior to the blastocyst stage, the mammalian embryo is insensitive to teratogenic and growth retarding radiation effects but is highly sensitive to the lethal radiation effect; (2) in the early organogenesis, the embryo is very sensitive to growth retarding, teratogenic and lethal radiation effects. It can, however, partly offset growth retardation in the post-natal period; (3) in the early fetal development stage, the fetus shows reduced sensitivity to teratogenic damage of many organs; sensitivity of the central nervous system and growth retardation remain which can only be compensated post-natally with difficulties; (4) in the late stage of pregnancy the fetus is not significantly deformed as a result of irradiation but permanent cellular depletion can result in various organs and tissues post-natally if radiation doses are high. (L.O.). 22 refs

  8. The effect of non-uniform fuel rod temperatures on effective resonance integrals

    International Nuclear Information System (INIS)

    Reichel, A.

    1961-06-01

    The effective resonance integral for heterogeneous lattices can be reduced to the effective resonance integral for an equivalent homogeneous system with a fairly well defined error depending on lump size and geometry. This report investigates the effect of a radial parabolic temperature variation in cylindrical lumps on the equivalent homogeneous effective resonance integral. Also determined is the equivalent uniform temperature to be taken in the usual formulae to allow for non-uniform fuel rod temperature. This effective temperature is found to be T eff. = T s + 4/9 (T c - T s ) where T s and T c are the surface and central temperatures of the lump. (author)

  9. Effects of UV radiation on freshwater metazooplankton

    International Nuclear Information System (INIS)

    Tartarotti, B.

    1999-06-01

    There is evidence that fluxes of solar ultraviolet-B radiation (UV-B, 290-320 nm) are increasing over wide parts of the earth's surface due to stratospheric ozone depletion. UV radiation (290-400 nm) can have damaging effects on biomolecules and cell components that are common to most living organisms. The aim of this thesis is to gain a more thorough understanding of the potential impacts of solar radiation on freshwater metazooplankton. To detect UV-vulnerability in zooplankton populations dominating the zooplankton community of two clear-water, high mountain lakes located one in the Austrian Alps and another in the Chilean Andes, the survival of two copepod species was studied. The organisms were exposed to a 10- to 100-fold increase in UV-B radiation compared to those levels found at their natural, maximum daytime distribution. Both species vertically migrate and are pigmented. UV-absorbing compounds with a maximum absorption at ∼334 nm were also detected. Cyclops abyssorum tatricus, a common cyclopoid copepod species of Alpine lakes, was highly resistant to UV-B radiation and no significant lethal effect was observed. The calanoid copepod Boeckella gracilipes, frequent in Andean lakes, had a mortality ∼5 times higher in the treatment receiving full sunlight than in the UV-B excluded treatment (3.2 %) only when exposed for 70 h. The resistance of B. gracilipes was higher than that reported in the literature for the same species suggesting the existence of intraspecific differences in UV sensitivity. Survival, fecundity and development of the zooplankton community of a clear-water, high elevation Andean lake (33 o S) were studied with mesocosms experiments after prolonged UV exposure (48 days). When exposed to full sunlight, the population of the cladoceran Chydorus sphaericus and the rotifer Lepadella ovalis were strongly inhibited by UV-B, whereas both species were resistant to UV-A radiation. Conversely, UV-B radiation had no effect on the survival of the

  10. The role of magnetic resonance imaging and scintigraphy in the diagnosis of pathologic changes of the mandible after radiation therapy

    International Nuclear Information System (INIS)

    Bachmann, G.; Rau, W.S.; Roessler, R.; Klett, R.; Bauer, R.

    1996-01-01

    A prospective study of 85 patients with oral cancer, treated with high-dose radiation therapy was performed to assess the value of magnetic resonance imaging (MRI) and scintigraphy for diagnosis of pathologic changes in the mandible. During postradiotherapeutic monitoring, radiation osteomyelitis occurred in 12 cases, tumor recurrences infiltrating the mandible in five cases, and progressive periodontal disease in nine cases. MRI permitted early diagnosis of radiation osteomyelitis in 11 out of 12 cases; only two cases were false positive. In scintigraphy with 99m Tc-HDP, all alterations of the mandible, such as osteoradionecrosis, tumor infiltration, and periodontitis, showed a high uptake, resulting in a sensitivity of up to 100%, but a low specificity of 57%. Scintigraphy permitted assessment of the extension and location of the lesions. Both methods were superior to conventional radiography and clinical examination and should be integrated into a comprehensive follow-up program after radiation therapy. (au) 25 refs

  11. The role of magnetic resonance imaging and scintigraphy in the diagnosis of pathologic changes of the mandible after radiation therapy

    International Nuclear Information System (INIS)

    Bachmann, G.; Rau, W.S.; Roessler, R.; Klett, R.; Bauer, R.

    1996-01-01

    A prospective study of 85 patients with oral cancer, treated with high-dose radiation therapy, was performed to assess the value of magnetic resonance imaging (MRI) and scintigraphy for diagnosis of pathologic changes in the mandible. During postradiotherapeutic monitoring, radiation osteomyelitis occurred in 12 cases, tumor occurrences infiltrating the mandible in five cases, and progressive periodontal disease in nine cases. MRI permitted early diagnosis of radiation osteomyelitis in 11 out of 12 cases; only two cases were false positive. In scintigraphy with 99m Tc-HDP, all alterations of the mandible, such as osteoradionecrosis, tumor infiltration, and periodontitis, showed a high uptake, resulting in a sensitivity of up to 100%, but a low specificity of 57%. Scintigraphy permitted assessment of the extension and location of the lesions. Both methods were superior to conventional radiography and clinical examination and should be integrated into a comprehensive follow-up program after radiation therapy. (au) 14 refs

  12. The role of magnetic resonance imaging and scintigraphy in the diagnosis of pathologic changes of the mandible after radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bachmann, G.; Rau, W.S. [Justus-Liebig-University of Giessen, Dept. of Radiology, Giessen (Germany); Roessler, R. [Justus-Liebig-Univ., Dept. of Periodontology, Giessen (Germany); Klett, R.; Bauer, R. [Justus-Liebig-Univ., Dept. of Nuclear Medicine, Giessen (Germany)

    1996-06-01

    A prospective study of 85 patients with oral cancer, treated with high-dose radiation therapy, was performed to assess the value of magnetic resonance imaging (MRI) and scintigraphy for diagnosis of pathologic changes in the mandible. During postradiotherapeutic monitoring, radiation osteomyelitis occurred in 12 cases, tumor occurrences infiltrating the mandible in five cases, and progressive periodontal disease in nine cases. MRI permitted early diagnosis of radiation osteomyelitis in 11 out of 12 cases; only two cases were false positive. In scintigraphy with {sup 99m}Tc-HDP, all alterations of the mandible, such as osteoradionecrosis, tumor infiltration, and periodontitis, showed a high uptake, resulting in a sensitivity of up to 100%, but a low specificity of 57%. Scintigraphy permitted assessment of the extension and location of the lesions. Both methods were superior to conventional radiography and clinical examination and should be integrated into a comprehensive follow-up program after radiation therapy. (au) 14 refs.

  13. Cytogenetic effects of low-dose radiation

    International Nuclear Information System (INIS)

    Metalli, P.

    1983-01-01

    The effects of ionizing radiation on chromosomes have been known for several decades and dose-effect relationships are also fairly well established in the mid- and high-dose and dose-rate range for chromosomes of mammalian cells. In the range of low doses and dose rates of different types of radiation few data are available for direct analysis of the dose-effect relationships, and extrapolation from high to low doses is still the unavoidable approach in many cases of interest for risk assessment. A review is presented of the data actually available and of the attempts that have been made to obtain possible generalizations. Attention is focused on some specific chromosomal anomalies experimentally induced by radiation (such as reciprocal translocations and aneuploidies in germinal cells) and on their relevance for the human situation. (author)

  14. The late biological effects of ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1978-06-15

    Full text: The principal objective of the symposium was to review the current status of understanding of the late biological effects of ionizing radiation from external and internal sources. A second objective was to critically evaluate information obtained from epidemiological studies of human population groups as well as from animal experimentation in order to provide a solid scientific basis upon which problems of current concern, such as radiation protection standards and risk-benefit analysis, could be deliberated. Eighty-one papers were presented in 10 sessions which covered epidemiological studies of late effects in human populations exposed to internal and/or external ionizing radiation; quantitative and qualitative data from animal experimentation of late effects; methodological problems and modern approaches; factors influencing susceptibility or expression of late radiation injury; comparative evaluation of late effects induced by radiation and other environmental pollutants, and problems of risk assessment. In addition, there were two evening sessions for free discussion of problems of interpreting animal data, and of the epidemiological studies of occupationally exposed populations. Reports on atomic bomb survivors showed that these epidemiological studies are providing dependable data, such as dose-related excess infant mortality. The reports also revealed the need for consensus in the method employed in the interpretation of data. That was also the case with studies on occupationally exposed populations at Hanford plant, where disparate results were presented on radiation-induced neoplasia among radiation workers. These data are, however, considered not so significant in relative terms when compared to risks involved in other industries. It was recommended that national registry systems for the dosimetry and medical records of radiation workers be established and co-ordinated internationally in order to facilitate reliable epidemiological

  15. Long-term effects of radiation

    International Nuclear Information System (INIS)

    Smith, J.; Smith, T.

    1981-01-01

    It is pointed out that sources of long-term damage from radiation are two-fold. People who have been exposed to doses of radiation from initial early fallout but have recovered from the acute effects may still suffer long-term damage from their exposure. Those who have not been exposed to early fallout may be exposed to delayed fallout, the hazards from which are almost exclusively from ingesting strontium, caesium and carbon isotopes present in food; the damage caused is relatively unimportant compared with that caused by the brief doses from initial radiation and early fallout. A brief discussion is presented of the distribution of delayed long-lived isotope fallout, and an outline is sketched of late biological effects, such as malignant disease, cataracts, retarded development, infertility and genetic effects. (U.K.)

  16. Radiation effects on Brassica seeds and seedlings

    Science.gov (United States)

    Deoli, Naresh; Hasenstein, Karl H.

    2016-07-01

    Space radiation consists of high energy charged particles and affects biological systems, but because of its stochastic, non-directional nature is difficult to replicate on Earth. Radiation damages biological systems acutely at high doses or cumulatively at low doses through progressive changes in DNA organization. These damages lead to death or cause of mutations. While radiation biology typically focuses on mammalian or human systems, little is known as to how radiation affects plants. In addition, energetic ion beams are widely used to generate new mutants in plants considering their high-LET (Linear Energy Transfer) as compared to gamma rays and X-rays. Understanding the effect of ionizing radiation on plant provides a basis for studying effects of radiation on biological systems and will help mitigate (space) radiation damage in plants. We exposed dry and imbibed Brassica rapa seeds and seedling roots to proton beams of varying qualities and compared the theoretical penetration range of different energy levels with observable growth response. We used 1, 2 and 3 MeV protons in air at the varying fluences to investigate the effect of direct irradiation on the seeds (1012 - 1015 ions/cm2) and seedlings (1013 ions/cm2). The range of protons in the tissue was calculated using Monte-Carlo based SRIM (Stopping and Range of Ions in Matter) software. The simulation and biological results indicate that ions did not penetrate the tissue of dry or hydrated seeds at all used ion energies. Therefore the entire energy was transferred to the treated tissue. Irradiated seeds were germinated vertically under dim light and roots growth was observed for two days after imbibition. The LD50 of the germination was about 2×1014 ions/cm2 and about 5×1014 ions/cm2 for imbibed and dry seeds, respectively. Since seedlings are most sensitive to gravity, the change in gravitropic behavior is a convenient means to assess radiation damage on physiological responses other than direct tissue

  17. Effects of radiation on DNA

    International Nuclear Information System (INIS)

    Medina, V.F.O.

    1978-01-01

    Irradiation has been shown to depress DNA (deoxyribonucleic acid) synthesis resulting in deficient DNA synthesis. In one experiment, Hela S 3 cells completed the next division after a dose of 500 rads to 200 kw X-rays. Another experiment showed that the amount of DNA synthesized was dependent on the stage in the generation cycle at which the cells are irradiated (Giffites and Tolmach, 1975). DNA synthesis was measured by radioactive thymidine incorporation. The smallest deficiency (20-35%) after a dose of 500 rad X-ray was observed in Hela S 3 cells irradiated in early G 1 or early G 2 , while the greatest deficiency (55-70*) after 500 rad X-ray was found in cells irradiated at mitosis or at the Gsub(1)/S transition. Using velocity sedimentation in alkaline gradients of the DNA from hamster, Elkind, et al 1972, studied repair processes as a function of X-ray dose. DNA containing material released by alkaline lysis was found initially contained in a complex-containing lipid, the sedimentation of which was anomalous relative to denatured RNA from unirradated cells. Doses of X-rays small enough to be in the range that permits high survival (100-800 rads) speed the resolution of single-stranded DNA from this DNA complex, giving rise to a species having a number average molecular weight of 2 x 10 8 daltons. Larger doses greater than 1000 to 2000 rads resulted in a degradation of these DNA strands. Incubation after irradiation resulted in the rapid repair of damage, although the rate of repair of damage to the complex resulted in a reassociation of lipid and DNA. This evidence supports the possibility that a large DNA-membrane structure is a principal target of radiation

  18. Detection of Moving Targets Using Soliton Resonance Effect

    Science.gov (United States)

    Kulikov, Igor K.; Zak, Michail

    2013-01-01

    The objective of this research was to develop a fundamentally new method for detecting hidden moving targets within noisy and cluttered data-streams using a novel "soliton resonance" effect in nonlinear dynamical systems. The technique uses an inhomogeneous Korteweg de Vries (KdV) equation containing moving-target information. Solution of the KdV equation will describe a soliton propagating with the same kinematic characteristics as the target. The approach uses the time-dependent data stream obtained with a sensor in form of the "forcing function," which is incorporated in an inhomogeneous KdV equation. When a hidden moving target (which in many ways resembles a soliton) encounters the natural "probe" soliton solution of the KdV equation, a strong resonance phenomenon results that makes the location and motion of the target apparent. Soliton resonance method will amplify the moving target signal, suppressing the noise. The method will be a very effective tool for locating and identifying diverse, highly dynamic targets with ill-defined characteristics in a noisy environment. The soliton resonance method for the detection of moving targets was developed in one and two dimensions. Computer simulations proved that the method could be used for detection of singe point-like targets moving with constant velocities and accelerations in 1D and along straight lines or curved trajectories in 2D. The method also allows estimation of the kinematic characteristics of moving targets, and reconstruction of target trajectories in 2D. The method could be very effective for target detection in the presence of clutter and for the case of target obscurations.

  19. Ultra violet radiation : effects on animals

    International Nuclear Information System (INIS)

    Stockdale, P.H.G.

    1993-01-01

    The paper deals with the evolutionary and historical events that have increased the susceptibility of certain genotypes of humanity and domestic animals to ultra violet radiation. Further it discusses the general effects of ultraviolet B (UVB) on vertebrates and then the clinical syndromes seen in such animals as a result of prolonged exposure to this form of radiation. Finally it gives anecdotal comments on evidence for changes in the immediately above types of disease and describes the need for a better recording system for these conditions so that these hypothetical changes could be effectively monitored. (author). 12 refs

  20. Genetic and chromosomal effects of ionizing radiation

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The genetic and chromosomal effects of ionizing radiations deal with those effects in the descendants of the individuals irradiated. The information base concerning genetic and chromosomal injury to humans from radiation is less adequate than is the information base for cancer and leukemia. As a result, it is not possible to make the kinds of quantitative estimates that have been made for carcinogenesis in previous chapters of this book. The chapter includes a detailed explanation of various types of genetic injuries such as chromosomal diseases, x-linked diseases, autosomal dominant diseases, recessive diseases, and irregularly inherited diseases. Quantitative estimates of mutation rates and incidences are given based on atomic bomb survivors data