Biokinetic of plutonium in human beings. Analysis and modification of ICRP 67 model; Biocinetica del plutonio nell'organismo umano. Analisi e modifica del modello ICRP 67

Energy Technology Data Exchange (ETDEWEB)

Luciani, A.; Castellani, C.M. [ENEA, Divisione Protezione dell' Uomo e degli Ecosistemi, Centro Ricerche Ezio Clementel, Bologna (Italy)

2001-07-01

A preliminary research of the available data and empirical functions for the plutonium excretion after injection was carried out. The ICRP model presented in the Publication no. 67 was then analyzed comparing its predictions for the activity in urine and, at a lesser extent, in feces and blood, with the collected data and empirical curves. The model was modified and an optimized age-related compartmental model was developed. A new skeletal model recently developed was also introduced and age depending bone remodelling rates were assumed on the basis of the ICRP Publication 70. This model provides a better agreement with measured urinary excretion data than the current ICRP 67 model, avoiding unphysiological assumptions such as the transfer of activity from soft tissue to urinary bladder, that were part of the ICRP model. The new optimized model predictions of the activity in faeces and in blood after an injection are also closer to the available data than the ICRP 67 estimations. A good agreement with the partitioning factor of plutonium between skeleton and liver obtained from different autopsy studies was also observed. [Italian] E' stata effettuata preliminarmente una ricerca bibliografica dei dati e delle funzioni di escrezione del plutonio attualmente disponibili in letteratura. Sulla base dei risultati di tale ricerca e' stato verificato il modello proposto dall'ICRP nella Pubblicazione n. 67. Tale modello e' stato quindi modificato al fine non solo di avere una piu' realistica descrizione dei valori predetti per l'escrezione urinaria, ma anche di modellare la cinetica del plutonio evitando quelle assunzioni introdotte appositamente nel modello dell'ICRP per correggere le previsini del modello ma che mancano di una chiara spiegazione di carattere fisiologico. Esso fornisce valutazioni piu' realistiche anche per l'attivita' nelle feci e nel sangue. Il modello sviluppato comprende un modello scheletrico

Basis for the ICRP's age-specific biokinetic model for uranium

International Nuclear Information System (INIS)

Leggett, R.W.

1994-01-01

In an effort motivated largely by the Chernobyl nuclear accident, the International Commission on Radiological Protection (ICRP) is developing age-specific biokinetic models and dose coefficients for environmentally important radionuclides. This paper describes the ICRP's age-specific biokinetic model for uranium. The model is constructed within a physiologically based framework originally developed for application to the alkaline earth elements but sufficiently general to apply to the larger class of bone-volume-seeking elements. Transfer rates for a reference adult are based mainly on: (1) measurements of uranium in blood and excreta of several human subjects who were intravenously injected with uranium; (2) postmortem measurements of uranium in tissues of some of those subjects; (3) postmortem measurements of uranium in tissues of occupationally and non-occupationally exposed subjects; (4) data on baboons, dogs, and smaller laboratory animals exposed to uranium for experimental purposes; and (5) consideration of the physiological processes thought to control retention and translocation of uranium in the body. Transfer rates for the adult are extended to children by application of a set of generic assumptions applied by the ICRP to calcium-like elements. These assumptions were derived mainly from observations of the age-specific biokinetics of the alkaline earth elements and lead in humans and laboratory animals but are consistent with available age-specific biokinetic data on uranium. 82 refs., 17 figs., 8 tabs

Comparison of old and new ICRP models for respiratory tract dosimetry

International Nuclear Information System (INIS)

Boecker, B.B.

1993-01-01

This paper examines the historical development and application of respiratory tract dosimetry models by the International Commission for Radiological Protection, ICRP, for health protection from inhaled radioactive aerosols. Three different models are discussed, those that were included in ICRP recommendations published in 1960 and 1979, and the new ICRP Publication 66. Basic features of these models are compared and contrasted. These features include model structure, sites and frequencies of particle deposition, processes and rates of clearance of the deposited material from the respiratory tract, and consideration of the parameters involved in these processes and how various factors can influence these parameters. All three models lead to the calculation of absorbed radiation doses with differing degrees of regional and local specificity. These calculations are achieved using different tools ranging from quick hand calculations to sophisticated computerized modeling approaches. A side-by-side review of these models indicates several important trends in respiratory tract dosimetry models, the most obvious of which is the increased complexity of each new model over the past 30+ years. These increases reflect both the increasing size of the knowledge base derived from studies in laboratory animals and in human subjects and the need for models more broadly applicable for both occupational and environmental exposures. It is likely that future research will be directed to those key aspects of the new model having the largest uncertainties. The detailed design of the new model and its associated software provide excellent means of identifying useful research areas and using the resulting new information in organized and productive ways

UK experience with ICRP26 and ICRP30

International Nuclear Information System (INIS)

Dray, C.H.

1991-01-01

ICRP26 was adopted in January 1977 which took into account information emerging since the adoption of ICRP9 in September 1969 and specified the basic criteria for dose limitation which still apply today. ICRP30 defines the limits for intakes for radionuclides for workers, and enables the health physicist and regulatory bodies to make appropriate limits for annual intake, air contamination etc, to comply requirements of dose-equivalent commitment and committed dose equivalent. The publication of ICRP26 is reflected in European Communities directive 80/836/Euratom. Council Directive of 15th July 1980 amending the Directive laying down the basic safety standards for the health protection of general public and workers against the dangers of ionizing radiations. This document being required the member states to bring the requirements of the directive within their legislation. In the United Kingdom this was accomplished by the publication of the Ionizing Radiations Regulations 1985

An empirical model describing the postnatal growth of organs in ICRP reference humans: Pt. 1

International Nuclear Information System (INIS)

Walker, J.T.

1991-01-01

An empirical model is presented for describing the postnatal mass growth of lungs in ICRP reference humans. A combined exponential and logistic function containing six parameters is fitted to ICRP 23 lung data using a weighted non-linear least squares technique. The results indicate that the model delineates the data well. Further analysis shows that reference male lungs attain a higher pubertal peak velocity (PPV) and adult mass size than female lungs, although the latter reach their PPV and adult mass size first. Furthermore, the model shows that lung growth rates in infants are two to three orders of magnitude higher than those in mature adults. This finding is important because of the possible association between higher radiation risks in infants' organs that have faster cell turnover rates compared to mature adult organs. The significance of the model for ICRP dosimetric purposes will be discussed. (author)

Simulation of the respiratory model of tract of Publication 66 of the ICRP and their use in biological analysis

International Nuclear Information System (INIS)

Puerta, A.

2001-01-01

The International Commission Radiological Protection, ICRP in its publications 67, 68, 69 and 71 provides the loss of systematic activity of the radioactive materials by the routes of excretion and recirculation, as well as effective dose by incorporation unit coefficient, using the model of respiratory tract proposed by the ICRP, in its Publication 66, but it does not provide information on as these models in biological analysis are used. There are some specific studies for inhalation of uranium compounds made by Bertelli and collaborators using the new model of the lung. In this work it have been done a simulation of the model of respiratory tract of ICRP 66 of such form that it can be used in-vitro and in-vivo biological analysis. In order to verify the simulation were used systemic models for adult of planuin, lead, uranium, bismuth and their respective descendants and the comparison with the coefficients of dose provided by the ICRP. Finally, it shows the estimation of the temporary distribution of activity in devices and the excrete of these radionuclides and in addition the model for gases and steam in the conditions is verified that the ICRP proposes

Current Activities and Plans of ICRP

International Nuclear Information System (INIS)

Valentin, J.

2001-01-01

Full text: The International Commission on Radiological Protection (ICRP) is established to advance for the public benefit the science of (ionising) radiation protection by providing recommendations and guidance, aiming at an appropriate standard of protection without unduly limiting beneficial practices. The Main Commission of ICRP recently launched a Task Group on new, consolidated Recommendations, based on world-wide consultations through IRPA on concepts proposed by the ICRP Chairman. It has also established a Task Group on protection of the environment, to review the Commission's policy that if humans are protected to the degree thought necessary, then other species are adequately protected. Task Groups of Committee 1 (Radiation effects) are planning reports on cancer risks at low doses; radiation effects on the embryo/fetus; and radiation quality effects. Committee 2 (Doses from radiation exposures) has Task Groups on internal dosimetry and on dose calculations, currently drafting reports on embryo/fetus dose coefficients; application of the ICRP lung model, and radionuclide transfer to breast milk. Task Groups on the human alimentary tract and on reference man are also preparing reports. Committee 3 (Protection in medicine) has initiated a series of practical reports on pregnancy and medical radiation; interventional radiology; accident prevention in radiotherapy; computed tomography; and release of patients after therapy with unsealed sources; as well as its series on new radiopharmaceuticals. Committee 4 (Application of ICRP recommendations) is providing input to the Main Commission Task Groups and is proposing a Task Group on radiation in space flight. Information about ICRP activities is available at www.icrp.org. (author)

Simulation of the respiratory model of tract of Publication 66 of the ICRP and their use in biological analysis; Simulacion del modelo de tracto respiratorio de la Publicacion 66 de la ICRP y su utilizacion en bioanalisis

Energy Technology Data Exchange (ETDEWEB)

Puerta, A. [Universidad Nacional de Colombia, Medellin (Colombia). Facultad de Ciencias. Dept. de Fisica; Bertelli, L.; Lipsztein, J. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)

2001-07-01

The International Commission Radiological Protection, ICRP in its publications 67, 68, 69 and 71 provides the loss of systematic activity of the radioactive materials by the routes of excretion and recirculation, as well as effective dose by incorporation unit coefficient, using the model of respiratory tract proposed by the ICRP, in its Publication 66, but it does not provide information on as these models in biological analysis are used. There are some specific studies for inhalation of uranium compounds made by Bertelli and collaborators using the new model of the lung. In this work it have been done a simulation of the model of respiratory tract of ICRP 66 of such form that it can be used in-vitro and in-vivo biological analysis. In order to verify the simulation were used systemic models for adult of planuin, lead, uranium, bismuth and their respective descendants and the comparison with the coefficients of dose provided by the ICRP. Finally, it shows the estimation of the temporary distribution of activity in devices and the excrete of these radionuclides and in addition the model for gases and steam in the conditions is verified that the ICRP proposes.

Alkaline earth metabolism: the ICRP model reformulated as a semi-Markov model

International Nuclear Information System (INIS)

Marcus, A.H.; Becker, A.

1980-01-01

Compartmental models are reformulated so as to allow power function or mixed exponential-power function residence time distributions in bone compartments. Numerical results reported for retention functions of calcium, strontium, barium and radium are in reasonable agreement with the ICRP models except at shorter time scales. The number of visits to bone is also sensitive to short-term elimination parameters, so that recycling corrections may require much more detailed analyses at both long and short time-scales. (author)

Acute ingestion dosimetry using the ICRP 30 gastrointestinal tract model

International Nuclear Information System (INIS)

Cassels, B.M.

1987-01-01

This paper examines the gastrointestinal (GI) tract model used for dosimetry as outlined in ICRP30, to allow quick calculations of effective dose equivalents for acute radionuclide ingestion. A computer program has been developed to emulate the GI tract model. The program and associated data files are structured so that the GI tract model parameters can be varied, while the file structure and algorithm for the GI tract model should require minimal modification to allow the same theories that apply in this model to be used for other dosimetric models

New ICRP recommendations on occupational limits for radon daughters

International Nuclear Information System (INIS)

Jacobi, W.

1981-01-01

The ICRP has recommended in 1959 for the first time a maximum permissible concentration (MPC) for the occupational exposure to radon and its short-lived daughters. Since this time more realistic dosimetric models for radon daughters have been developed. Taking into account epidemiological and new dosimetric findings the ICRP has adopted in March this year new recommendations on occupational limits for inhalation of 222 Rn, 220 Rn and their short-lived daughters. This report will be published this year as ICRP Publication 32 (ICRP 1981). The recommended limits for radon daughters were derived from the basic dose and risk limits as they were proposed by ICRP in its new basic recommendations (ICRP Publ. 26, 1977). In the following this basic system of dose limitation is shortly outlined before the special recommendations for radon daughters are described

ICRP Publication 116—the first ICRP/ICRU application of the male and female adult reference computational phantoms

CERN Document Server

Petoussi-Henss, Nina; Eckerman, Keith F; Endo, Akira; Hertel, Nolan; Hunt, John; Menzel, Hans G; Pelliccioni, Maurizio; Schlattl, Helmut; Zankl, Maria

2014-01-01

ICRP Publication 116 on `Conversion coefficients for radiological protection quantities for external radiation exposures', provides fluence-to-dose conversion coefficients for organ-absorbed doses and effective dose for various types of external exposures (ICRP 2010 ICRP Publication 116). The publication supersedes the ICRP Publication 74 (ICRP 1996 ICRP Publication 74, ICRU 1998 ICRU Report 57), including new particle types and expanding the energy ranges considered. The coefficients were calculated using the ICRP/ICRU computational phantoms (ICRP 2009 ICRP Publication 110) representing the reference adult male and reference adult female (ICRP 2002 ICRP Publication 89), together with a variety of Monte Carlo codes simulating the radiation transport in the body. Idealized whole-body irradiation from unidirectional and rotational parallel beams as well as isotropic irradiation was considered for a large variety of incident radiations and energy ranges. Comparison of the effective doses with operational quantit...

Impact of ICRP publication 68

International Nuclear Information System (INIS)

Carter, M.W.; Woods, D.A.

1996-01-01

ICRP Publication 61 was a temporary replacement for ICRP Publication 30. It gave ALIs but not the underlying dose conversion factors. ICRP Publication 68 has now been issued to replace Publication 61; it contains the dose conversion factors but not the ALIs, so comparison is impossible without carrying out calculations. This paper presents comparisons between the two publications and calculates the ICRP Publication 68 ALIs for some of the more common radionuclides. (author)

Improvement of skeleton conversion in ICRP reference phantom conversion project

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhao Jun; Yeom, Yeon Soo; Thang, Nguyen Tat; Kim, Han Sung; Han, Min Cheol; Kim, Chan Hyeong [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of); Kim, Seong Hoon [Dept. of Radiation Oncology, College of Medicine, Hanyang University, Seoul (Korea, Republic of)

2014-11-15

In the previous skeleton conversion, most bones were directly converted from the ICRP voxel phantoms by using the 3D rendering method whereas several complex-shape bones (cranium, ribs, spines, feet, and hands) were not able to be directly converted. We alternatively employed the corresponding well-defined polygonal models and attempted to adjust them to match the voxel models. However, this approach was unsatisfactory. The shapes of the alternative models were significantly different from those of the voxel models, making it virtually impossible to exactly match the voxel models as shown in Fig. 3 (left). In order to overcome the difficulty in the complex bone conversion, the present study developed a new conversion method and converted these complex bones voxel models of the ICRP male phantom to polygonal models. The present study developed the new conversion method and successfully improved polygonal models for cranium, ribs, and spines for the ICRP male phantom. The new conversion method will be also applied to the complex bone conversion for the ICRP female phantom as well as other complex organ conversion in the future.

Improvement of skeleton conversion in ICRP reference phantom conversion project

International Nuclear Information System (INIS)

Wang, Zhao Jun; Yeom, Yeon Soo; Thang, Nguyen Tat; Kim, Han Sung; Han, Min Cheol; Kim, Chan Hyeong; Kim, Seong Hoon

2014-01-01

In the previous skeleton conversion, most bones were directly converted from the ICRP voxel phantoms by using the 3D rendering method whereas several complex-shape bones (cranium, ribs, spines, feet, and hands) were not able to be directly converted. We alternatively employed the corresponding well-defined polygonal models and attempted to adjust them to match the voxel models. However, this approach was unsatisfactory. The shapes of the alternative models were significantly different from those of the voxel models, making it virtually impossible to exactly match the voxel models as shown in Fig. 3 (left). In order to overcome the difficulty in the complex bone conversion, the present study developed a new conversion method and converted these complex bones voxel models of the ICRP male phantom to polygonal models. The present study developed the new conversion method and successfully improved polygonal models for cranium, ribs, and spines for the ICRP male phantom. The new conversion method will be also applied to the complex bone conversion for the ICRP female phantom as well as other complex organ conversion in the future

The ICRP working party on bioassay interpretation

International Nuclear Information System (INIS)

Fry, F.A.; Lipsztein, J.L.; Birchall, A.

2003-01-01

In recent years there have been many developments in modelling the behaviour of radionuclides in the human body. The current generation of models are designed to be more 'realistic' than the previous generation of simple compartment models. The International Commission on Radiological Protection (ICRP) uses these models to produce dose coefficients and recognises that there is a need to give more guidance on how these models can be used to interpret bioassay data. A working party has been set up to address the issue. This paper describes some of the problems, some approaches to solving the problems and the progress of the ICRP working party. (author)

Safety philosophy of ICRP

International Nuclear Information System (INIS)

Kato, Kazuaki

1995-01-01

Measures are important as the means to realize philosophy. Accordingly, it is meaningful to take measures as the object when the philosophy of ICRP is considered. As to controllable risk factors, restraint shall be done so as to make the risk being brought about as small as possible. When it is not necessary to limit restraining means, risk-free is ideal. Ionizing radiation is one of risk factors. The risk that ICRP speaks is the loss of the probability of maintaining life. The object of radiation protection is limited to the exposure to controllable radiation, and the aim of protection is to minimize risk under the condition of as low as reasonably achievable. The philosophy of ICRP and the problems in the measures are discussed. ICRP and ICRU must reconfirm the allotment of roles. Radiation protection system is composed of system of radiation dosimetry and system of dose limitation. The mission of ICRP is to recommend political decision, and it may make the political declaration 'The radiation below a certain amount may be regarded as safe'. It is better only to recommend the conversion relation of radiation dose and risk. The desire and demand to ICRP are mentioned. (K.I.)

System and circuit models for microwave antennas

OpenAIRE

Sobhy, Mohammed; Sanz-Izquierdo, Benito; Batchelor, John C.

2007-01-01

This paper describes how circuit and system models are derived for antennas from measurement of the input reflection coefficient. Circuit models are used to optimize the antenna performance and to calculate the radiated power and the transfer function of the antenna. System models are then derived for transmitting and receiving antennas. The most important contribution of this study is to show how microwave structures can be integrated into the simulation of digital communication systems. Thi...

Relevance of the ICRP biokinetic model for dietary organically bound tritium

International Nuclear Information System (INIS)

Trivedi, A.

1999-10-01

Ingested dietary tritium can participate in metabolic processes, and become synthesized into organically bound tritium in the tissues and organs. The distribution and retention of the organically bound tritium throughout the body are much different than tritium in the body water. The International Commission on Radiological Protection (ICRP) Publication 56 (1989) has a biokinetic model to calculate dose from the ingestion of organically bound dietary tritium. The model predicts that the dose from the ingestion of organically bound dietary tritium is about 2.3 times higher than from the ingestion of the same activity of tritiated water. Under steady-state conditions, the calculated dose rate (using the first principle approach) from the ingestion of dietary organically bound tritium can be twice that from the ingestion of tritiated water. For an adult, the upper-bound dose estimate for the ingestion of dietary organically bound tritium is estimated to be close to 2.3 times higher than that of tritiated water. Therefore, given the uncertainty in the dose calculation with respect to the actual relevant dose, the ICRP biokinetic model for organically bound tritium is sufficient for dosimetry for adults. (author)

Comparison of Radiation Dose Rates with the Flux to Dose Conversion Factors Recommended in ICRP-74 and ICRP-116

International Nuclear Information System (INIS)

Jeong, Hae Sun; Kil, A Reum; Lee, Jo Eun; Jeong, Hyo Joon; Kim, Eun Han; Han, Moon Hee; Hwang, Won Tae

2016-01-01

The evaluation of radiation shielding has been performed for the design and maintenance of various facilities using radioactive sources such as nuclear fuel, accelerator, and radionuclide. The conversion of flux to dose mainly used in nuclear and radiation fields has been generally made with the dose coefficients presented in ICRP Publication 74 (ICRP- 74), which are produced based on ICRP Publication 60. On the other hand, ICRP Publication 116 (ICRP-116), which adopts the protection system of ICRP Publication 103, has recently been published and provides the dose conversion coefficients calculated with a variety of Monte Carlo codes. The coefficients have more than an update of those in ICRP-74, including new particle types and a greatly expanded energy range. In this study, a shielding evaluation of a specific container for neutron and gamma sources was performed with the MCNP6 code. The dose rates from neutron and gamma-ray sources were calculated using the MCNP6 codes, and these results were based on the flux to dose conversion factors recommended in ICRP-74 and ICRP-116. As a result, the dose rates evaluated with ICRP-74 were generally shown higher than those with ICRP-116. For neutrons, the difference is mainly occurred by the decrease of radiation weighting factors in a part of energy ranges in the ICRP-116 recommendations. For gamma-rays, the ICRP-74 recommendation applied with the kerma approximation leads to overestimated results than the other assessment

ICRP: Engaging with the RP profession

International Nuclear Information System (INIS)

Clement, Ch

2014-01-01

Just as the ICRP system of radiological protection must adapt to changes in scientific understanding, social and ethical values, and practical experience, ICRP itself continues to adapt as an organisation. One aspect of the continual modernisation of ICRP is a greater emphasis on engaging with the radiological protection profession.Ten years ago, on August 8, 2004, ICRP formally began open consultation on what was then referred to as the draft “2005 Recommendations of ICRP”. As most readers will know, this was published in due course as ICRP Publication 103, “The 2007 Recommendations of the International Commission on Radiological Protection” (ICRP, 2007).Being managed through the ICRP website, it opened up the possibility for anyone, anywhere, with an internet connection and an interest in radiological protection, to review the draft document and submit comments directly to ICRP.Open consultation on draft publications is but one aspect of ICRP’s efforts to become a more open and transparent organisation, and to increase engagement with the radiological protection profession. A modern arrangement for formal relations with other international organisations was established in 2012 with the objective of being more inclusive, effective, and efficient. In addition, there are efforts underway to seek the support needed to enable ICRP to broaden awareness of our recommendations, particularly in the medical field, and to increase engagement through social media and at relevant conferences, symposia, meetings, etc

Practical application of the new ICRP Human Respiratory Tract Model (invited paper)

Energy Technology Data Exchange (ETDEWEB)

Bailey, M.R.; Guilmette, R.A.; Jarvis, N.S.; Roy, M

1998-07-01

The ICRP Publication 66 Human Respiratory Tract Model (HRTM) has been applied to calculate general-purpose dose coefficients using default values of parameters relating to the material and the subjects. The ICRP Task Group on Internal Dosimetry is developing a 'Technical Document' giving guidance on application of the HRTM in situations where using specific information can improve dose assessment. It will include an analysis of the sensitivity of doses and bioassay quantities, lung retention and excretion rates, to relevant parameter values. Guidance will be given on characterising and sampling radioactive aerosols and on determining absorption rates. Examples will be given illustrating application of the HRTM in a wide range of situations. This paper provides a selective summary of the document at its current stage of development, with emphasis on determining absorption rates. (author)

Possible implications of draft ICRP recommendations

International Nuclear Information System (INIS)

2003-01-01

The Committee on Radiation Protection and Public Health (CRPPH) of the OECD Nuclear Energy Agency (NEA) has, since its inception, worked to develop and improve international norms in the area of radiological protection of the public, workers and the environment. International radiological protection norms continue to evolve, with significant new steps having been taken by the International Radiological Protection Commission (ICRP). Since the issuance of its 1990 recommendations, which form the basis of the international system of radiological protection, the ICRP has continued to add to them. The sum of these recommendations has become overly complicated and at times incoherent. In 1999 the ICRP therefore began to re-evaluate its recommendations with the aim of consolidation, simplification and clarification. New ICRP recommendations are due to be published in 2005. The CRPPH is contributing to the development of these new recommendations by providing the views of regulators and practitioners from its member countries. This report summarises the views of the CRPPH regarding the conceptual framework that the ICRP has recently proposed as the basis for its forthcoming detailed recommendations. The CRPPH highly appreciates the open stakeholder process that the ICRP has initiated to gather input for the development of new recommendations. This document, which is supported by the NEA Committee on Radiation Protection and Public Health, and by the NEA Radioactive Waste Management Committee, provides detailed suggestions with regard to the proposed ICRP framework. The stakeholder views expressed in this report have been presented to the ICRP at the second NEA/ICRP Forum in April 2003, and have persuaded the ICRP to reintroduce several key concepts into its proposed new system. (author)

Data file on retention and excretion of inhaled radionuclides calculated using ICRP dosimetric models

International Nuclear Information System (INIS)

Ishigure, Nobuhito; Nakano, Takashi; Enomoto, Hiroko; Shimo, Michikuni; Inaba, Jiro

2000-01-01

The authors have computed whole-body or a specific organ content and the daily urinary and faecal excretion rate of some selected radionuclides following acute intake by inhalation and ingestion, where the ICRP new respiratory tract model (ICRP Publication 66) and the latest ICRP biokinetic models were applied. The results were compiled in a file of MS Excel. The file was tentatively called MONDAI for reference. MONDAI contains the data for all radionuclides in ICRP Publications 54 and 78 and, in addition, some other radionuclides which are important from the viewpoint of occupational exposure in nuclear industry, research and medicine. They are H-3, P-32, Cr-51, Mn-54, Fe-59, Co-57, Co-58, Co-60, Zn-65, Rb-86, Sr-85, Sr-89, Sr-90, Zr-95, Ru-106, Ag-110m, Sb-124, Sb-125, I-125, I-129, I-131, Cs-134, Cs-137, Ba-140, Ce-141, Ce-144, Hg-203, Ra-226, Ra-228, Th-228, Th-232, U-234, U-235, U-238, Np-237, Pu-238, Pu-239, Pu-240, Am-241, Cm-242, Cm-244 and Cf-252. The day-by-day data up to 1000 days and the data at every 10 days up to 10000 days are presented. The following ICRP default values for the physical characteristics of the radioactive aerosols were used: AMAD=5 micron, geometric SD=2.5, particle density = 3 g/cm 3 , particle shape factor = 1.5. The subject exposed to the aerosols is the ICRP reference worker doing light work: light exercise with the ventilation rate of 1.5 m 3 /h for 5.5 h + sitting with the ventilation rate of 0.54 m 3 /h for 2.5 h. MONDAI was originally made by Version 7.0 of MS Excel for Windows 95, but the file was saved in the form of Ver. 4.0 as well as Ver. 7.0. Therefore, if the user has Ver. 4.0 or an upper version, he can open the file and operate it. With the graph-wizard of MS Excel the user can easily make a diagram for the retention or daily excretion of a radionuclide of interest. The dose coefficient (Sv/Bq intake) of each radionuclide for each absorption type given in ICRP Publication 68 was also written in each sheet. Therefore

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

International Nuclear Information System (INIS)

Wahl, L.E.

1994-03-01

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

Reliability of the ICRP's dose coefficients for members of the public: IV. Basis of the human alimentary tract model and uncertainties in model predictions

International Nuclear Information System (INIS)

Leggett, R.; Harrison, J.; Phipps, A.

2007-01-01

The biokinetic and dosimetric model of the gastrointestinal (GI) tract applied in current documents of the International Commission on Radiological Protection (ICRP) was developed in the mid-1960's. The model was based on features of a reference adult male and was first used by the ICRP in Publication 30, Limits for Intakes of Radionuclides by Workers (Part 1, 1979). In the late 1990's an ICRP task group was appointed to develop a biokinetic and dosimetric model of the alimentary tract that reflects updated information and addresses current needs in radiation protection. The new age-specific and gender-specific model, called the Human Alimentary Tract Model (HATM), has been completed and will replace the GI model of Publication 30 in upcoming ICRP documents. This paper discusses the basis for the structure and parameter values of the HATM, summarises the uncertainties associated with selected features and types of predictions of the HATM and examines the sensitivity of dose estimates to these uncertainties for selected radionuclides. Emphasis is on generic biokinetic features of the HATM, particularly transit times through the lumen of the alimentary tract, but key dosimetric features of the model are outlined, and the sensitivity of tissue dose estimates to uncertainties in dosimetric as well as biokinetic features of the HATM are examined for selected radionuclides. (authors)

Design of reconfigurable antennas using graph models

CERN Document Server

Costantine, Joseph; Christodoulou, Christos G; Christodoulou, Christos G

2013-01-01

This lecture discusses the use of graph models to represent reconfigurable antennas. The rise of antennas that adapt to their environment and change their operation based on the user's request hasn't been met with clear design guidelines. There is a need to propose some rules for the optimization of any reconfigurable antenna design and performance. Since reconfigurable antennas are seen as a collection of self-organizing parts, graph models can be introduced to relate each possible topology to a corresponding electromagnetic performance in terms of achieving a characteristic frequency of oper

Voxel-based models representing the male and female ICRP reference adult - the skeleton

International Nuclear Information System (INIS)

Zankl, M.; Eckerman, K.F.; Bolch, W.E.

2007-01-01

For the forthcoming update of organ dose conversion coefficients, the International Commission on Radiological Protection (ICRP) will use voxel-based computational phantoms due to their improved anatomical realism compared with the class of mathematical or stylized phantoms used previously. According to the ICRP philosophy, these phantoms should be representative of the male and female reference adults with respect to their external dimensions, their organ topology and their organ masses. To meet these requirements, reference models of an adult male and adult female have been constructed at the GSF, based on existing voxel models segmented from tomographic images of two individuals whose body height and weight closely resemble the ICRP Publication 89 reference values. The skeleton is a highly complex structure of the body, composed of cortical bone, trabecular bone, red and yellow bone marrow and endosteum ('bone surfaces' in their older terminology). The skeleton of the reference phantoms consists of 19 individually segmented bones and bone groups. Sub-division of these bones into the above-mentioned constituents would be necessary in order to allow a direct calculation of dose to red bone marrow and endosteum. However, the dimensions of the trabeculae, the cavities containing bone marrow and the endosteum layer lining these cavities are clearly smaller than the resolution of a normal CT scan and, thus, these volumes could not be segmented in the tomographic images. As an attempt to represent the gross spatial distribution of these regions as realistically as possible at the given voxel resolution, 48 individual organ identification numbers were assigned to various parts of the skeleton: every segmented bone was subdivided into an outer shell of cortical bone and a spongious core; in the shafts of the long bones, a medullary cavity was additionally segmented. Using the data from ICRP Publication 89 on elemental tissue composition, from ICRU Report 46 on material

Human respiratory tract model for radiological protection: A revision of the ICRP Dosimetric Model for the Respiratory System

International Nuclear Information System (INIS)

Bair, W.J.

1989-01-01

In 1984, the International Commission on Radiological Protection (ICRP) appointed a task group of Committee 2 to review and revise, as necessary, the ICRP Dosimetric Model for the Respiratory System. The model was originally published in 1966, modified slightly in Publication No. 19, and again in Publication No. 30 (in 1979). The task group concluded that research during the past 20 y suggested certain deficiencies in the ICRP Dosimetric Model for the Respiratory System. Research has also provided sufficient information for a revision of the model. The task group's approach has been to review, in depth, morphology and physiology of the respiratory tract; deposition of inhaled particles in the respiratory tract; clearance of deposited materials; and the nature and specific sites of damage to the respiratory tract caused by inhaled radioactive substances. This review has led to a redefinition of the regions of the respiratory tract for dosimetric purposes. The redefinition has a morphologic and physiological basis and is consistent with observed deposition and clearance of particles and with resultant pathology. Regions, as revised, are the extrathoracic (E-T) region, comprising the nasal and oral regions, the pharynx, larynx, and upper part of the trachea; the fast-clearing thoracic region (T[f]), comprising the remainder of the trachea and bronchi; and the slow-clearing thoracic region (T[s]), comprising the bronchioles, alveoli, and thoracic lymph nodes. A task group report will include models for calculating radiation doses to these regions of the respiratory tract following inhalation of representative alpha-, beta-, and gamma-emitting particulate and gaseous radionuclides. The models may be implemented as a package of computer codes available to a wide range of users

The postnatal growth of ICRP target organs in reference humans: Spleen and liver

International Nuclear Information System (INIS)

Walker, J.T.

1989-01-01

Attempts to improve radiation dose estimates to infants and children are hampered because of the lack of mathematical models that describe the age variation in anatomical and physiological parameters. Specifically, for one anatomical parameter, organ size, there are no growth models available to the health physics community. In this paper, an empirical mathematical model is introduced for estimating age-specific masses of two ICRP target organs: the spleen and liver. That model, the Power Logistic Additive (PLA) growth model, is fitted to ICRP 23 organ growth data to determine five growth parameters. This model assumes that organs grow under the influence of two main processes: a primary (power function) and a sexual maturation (logistic function) process, which are additive from birth to adulthood. The results show that the model describes the ICRP growth data quite well. Growth parameters and tables listing the predicted masses and mass velocities as a function of age for each organ are provided for application in the ICRP modeling system

The ICRP task group respiratory tract model - an age-dependent dosimetric model for general application

International Nuclear Information System (INIS)

Bailey, M.R.; Birchall, A.

1992-01-01

The ICRP Task Group on Human Respiratory Tract Models for Radiological Protection has developed a revised dosimetric model for the respiratory tract. Papers outlining the model, and describing each aspect of it were presented at the Third International Workshop on Respiratory Tract Dosimetry (Albuquerque 1-3 July 1990), the Proceedings of which were recently published in Radiation Protection Dosimetry Volume 38 Nos 1-3 (1991). Since the model had not changed substantially since the Workshop at Albuquerque, only a summary of the paper presented at Schloss Elmau is included in these Proceedings. (author)

Modeling of Antenna for Deep Target Hydrocarbon Exploration

Directory of Open Access Journals (Sweden)

Nadeem Nasir

2017-11-01

Full Text Available Nowadays control source electromagnetic method is used for offshore hydrocarbon exploration. Hydrocarbon detection in sea bed logging (SBL is a very challenging task for deep target hydrocarbon reservoir. Response of electromagnetic (EM field from marine environment is very low and it is very difficult to predict deep target reservoir below 2km from the sea floor. This work premise deals with modeling of new antenna for deep water deep target hydrocarbon exploration. Conventional and new EM antennas at 0.125Hz frequency are used in modeling for the detection of deep target hydrocarbon  reservoir.  The  proposed  area  of  the  seabed model   (40km ´ 40km   was   simulated   by using CST (computer simulation technology EM studio based on Finite Integration Method (FIM. Electromagnetic field components were compared at 500m target depth and it was concluded that Ex and Hz components shows better resistivity contrast. Comparison of conventional and new antenna for different target  depths  was  done in  our  proposed  model.  From  the results, it was observed that conventional antenna at 0.125Hz shows 70% ,86% resistivity contrast at target depth of 1000m where   as   new   antenna   showed   329%, 355%   resistivity contrast at the same target depth for Ex and Hz field respectively.  It  was  also  investigated  that  at  frequency of0.125Hz, new antenna gave 46% better delineation of hydrocarbon at 4000m target depth. This is due to focusing of electromagnetic waves by using new antenna. New antenna design gave 125% more extra depth than straight antenna for deep target hydrocarbon detection. Numerical modeling for straight  and  new antenna  was also done to know general equation for electromagnetic field behavior with target depth. From this numerical model it was speculated that this new antenna can detect up to 4.5 km target depth. This new EM antenna may open new frontiers for oil and gas

ICRP new recommendations. Committee 2's efforts

International Nuclear Information System (INIS)

Eckerman, K.F.

2007-01-01

The International Commission on Radiological Protection (ICRP) may release new primary radiation protection recommendation in 2007. Committee 2 has underway reviews of the dosimetric and biokinetic models and associated data used in calculating dose coefficients for intakes of radionuclides and exposures to external radiation fields. This paper outlines the work plans of Committee 2 during the current term, 2005-2009, in anticipation of the new primary recommendations. The two task groups of Committee 2 responsible for the computations of dose coefficients, INDOS and DOCAL, are reviewing the models and data used in the computations. INDOS is reviewing the lung model and the biokinetic models that describe the behavior of the radionuclides in the body. DOCAL is reviewing its computational formulations with the objective of harmonizing the formulation with those of nuclear medicine, and developing new computational phantoms representing the adult male and female reference individuals of ICRP Publication 89. In addition, DOCAL will issue a publication on nuclear decay data to replace ICRP Publication 38. While the current efforts are focused on updating the dose coefficients for occupational intakes of radionuclides plans are being formulated to address dose coefficients for external radiation fields which include consideration of high energy fields associated with accelerators and space travel and the updating of dose coefficients for members of the public. (author)

Correspondence of the ICRP database of dose coefficients (1996) to 2007 recommendations of the ICRP

International Nuclear Information System (INIS)

Kadatskaya, M.M.

2012-01-01

The new IAEA international safety standards, issued in 2011, recommend in practical implementation of the 2007 Recommendations of the ICRP continue to use dosimetric database developed in 1996. This article presents method and results of the calculation of committed effective dose of internal exposure in accordance with the new definition of this quantity given in 2007 Recommendations of the ICRP. It is shown that in the control of internal doses in accordance with the 2007 Recommendations of the ICRP it is allowed to use dose factors which were released in 1996. (authors)

Radiation protection. Basic concepts of ICRP

International Nuclear Information System (INIS)

Saito, Tsutomu; Hirata, Hideki

2014-01-01

The title subject is easily explained. Main international organizations for radiation protection are United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), International Commission on Radiological Protection (ICRP) and International Atomic Energy Agency (IAEA). The UNSCEAR objectively summarizes and publishes scientific findings; ICRP, an NGO, takes part in recommending the radiological protection from the expertized aspect; and IAEA, a UN autonomy, aims at peaceful usage of atomic power. These organizations support the legal regulation and standard of nations. The purpose of the ICRP recommendation (Pub. 103, 2007) is to contribute to the appropriate protection of radiation hazardous effects, which are assumed to be linearly proportional (the model of linear no-threshold, LNT) that radiation risk exists even at the lowest dose. When a change in the single cell results in hazardous alteration, the causative effects are called stochastic effects, which include the mutation leading to cancer formation and genetic effect in offspring (not observed in man). ICRP says the validity of LNT for the stochastic effects essentially from the protective aspect, although epidemiological data support it at >100 mSv exposure. The deterministic effects are caused by loss of cell itself or of its function, where the threshold is defined to be the dose causing >1% of disorder or death. Radiation protective system against exposure is on the situation (programmed, emergent and natural), category (occupational, public and medical) and 3 principles of justification, optimization and application of dose limit. (T.T.)

Internal dosimetry data and methods of ICRP. Part 1

International Nuclear Information System (INIS)

Ford, M.R.; Bernard, S.R.; Dillman, L.T.; Watson, S.B.

1978-01-01

The methodology being used to update the International Commission on Radiological Protection (ICRP) report of Committee 2, ICRP Publication 2 on Permissible Dose for Internal Radiation, is described. The system of differential equations, which is used to calculate the cumulated activity in the lungs, gastrointestinal tract, other body organs, and the transfer compartment of reference man, is presented. These equations describe the physical decay and metabolism of a radionuclide as governed by the lung and gastrointestinal tract models adopted by Committee 2 from models developed for the ICRP. The equations also take into account organ uptake and retention following intake into blood and the contribution of activity from radioactive daughter nuclides. Additionally, the scheme for estimating the dose from immersion in a radioactive cloud and the scheme for computing the nuclear decay data needed for all of the dose computations are presented. In computing the immersion dose, estimates for both the infinite and the finite cloud are considered

The new ICRP general recommendations

International Nuclear Information System (INIS)

Sasaki, Y.; Lochard, J.; Holm, L.E.; Niwa, O.; Ishigure, N.; Kosako, T.; Kai, M.

2007-01-01

The new draft ICRP recommendations was presented by the ICRP chair, Professor Lars-Eric Holm. His presentation was followed by presentations by Japanese members of the various (CRP committees, discussing their views of the draft recommendations based on their own technical experience. After these presentations, questions from the floor raised many of the key issues of the conference: dose constrains, the LNT hypothesis, dose bands, etc. This showed that the conference participants had carefully and completely read the draft, and were very interested in building a final ICRP recommendation that appropriately addresses all their concerns. These issues were also discussed throughout the entire conference. (author)

ICRP risk estimates - an alternative view

International Nuclear Information System (INIS)

Morgan, K.Z.

1987-01-01

This criticism of the worth of the ICRP Main Commission spans 60 years, reviewed by a member of the Commission. Beginning in 1960 two serious radiation exposure problems (occupational exposure in uranium mines and population exposure from testing of nuclear weapons) came to their attention. One might have expected ICRP to be the first to try to reduce these exposures but it was conspicuous by its silence. In 1958 ICRP set limits of exposure for radiation workers and member of the public. Nineteen years later (1977) when it was realized that the risk of radiation induced cancer was ten to thirty times what it was perceived to be in 1958, ICRP might have been expected to recommend a major reduction in permissible exposure levels, but to the dismay of some it increased them. It was also a great disappointment when in 1977, levels of MPC of radionuclides in air, water and food were increased for a large fraction of the more dangerous radionuclides. The reactor accident at Chernobyl calls for a number of new ICRP recommendations. When can we expect them? (author)

Development of skeletal system for mesh-type ICRP reference adult phantoms

Science.gov (United States)

Yeom, Yeon Soo; Wang, Zhao Jun; Tat Nguyen, Thang; Kim, Han Sung; Choi, Chansoo; Han, Min Cheol; Kim, Chan Hyeong; Lee, Jai Ki; Chung, Beom Sun; Zankl, Maria; Petoussi-Henss, Nina; Bolch, Wesley E.; Lee, Choonsik

2016-10-01

The reference adult computational phantoms of the international commission on radiological protection (ICRP) described in Publication 110 are voxel-type computational phantoms based on whole-body computed tomography (CT) images of adult male and female patients. The voxel resolutions of these phantoms are in the order of a few millimeters and smaller tissues such as the eye lens, the skin, and the walls of some organs cannot be properly defined in the phantoms, resulting in limitations in dose coefficient calculations for weakly penetrating radiations. In order to address the limitations of the ICRP-110 phantoms, an ICRP Task Group has been recently formulated and the voxel phantoms are now being converted to a high-quality mesh format. As a part of the conversion project, in the present study, the skeleton models, one of the most important and complex organs of the body, were constructed. The constructed skeleton models were then tested by calculating red bone marrow (RBM) and endosteum dose coefficients (DCs) for broad parallel beams of photons and electrons and comparing the calculated values with those of the original ICRP-110 phantoms. The results show that for the photon exposures, there is a generally good agreement in the DCs between the mesh-type phantoms and the original voxel-type ICRP-110 phantoms; that is, the dose discrepancies were less than 7% in all cases except for the 0.03 MeV cases, for which the maximum difference was 14%. On the other hand, for the electron exposures (⩽4 MeV), the DCs of the mesh-type phantoms deviate from those of the ICRP-110 phantoms by up to ~1600 times at 0.03 MeV, which is indeed due to the improvement of the skeletal anatomy of the developed skeleton mesh models.

Management of radon: a review of ICRP recommendations

International Nuclear Information System (INIS)

Vaillant, Ludovic; Bataille, Céline

2012-01-01

This article proposes a review of past and current ICRP publications dealing with the management of radon exposures. Its main objective is to identify and discuss the driving factors that have been used by the Commission during the last 50 years so as to better appreciate current issues regarding radon exposure management. The analysis shows that major evolutions took place in very recent years. As far as the management of radon exposures is concerned, ICRP recommended, until ICRP Publication 103 (ICRP 2007 ICRP Publication 103; Ann. ICRP 37), to use action levels and to consider only exposures above these levels. The Commission has reviewed its approach and now proposes to manage any radon exposure through the application of the optimisation principle and associated reference levels. As far as the assessment of the radon risk is concerned, it appears that the successive changes made by ICRP did not have a strong impact on the values of radon gas concentration recommended as action levels either in dwellings or in workplaces. The major change occurred in late 2009 with the publication of the ICRP Statement on Radon, which acknowledged that the radon risk has been underestimated by a factor of 2, thus inducing a major revision of radon reference levels. (review)

Conversion of ICRP male reference phantom to polygon-surface phantom

International Nuclear Information System (INIS)

Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong; Jeong, Jong Hwi

2013-01-01

The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (<2 man-months), we were able to construct the polygon-surface phantom with the organ masses perfectly matching the ICRP reference values. The analysis of the calculated dose values also implies that the dose values are indeed not very sensitive to the detailed morphology of the organ models in the phantom

Application of the new ICRP respiratory tract model to inhaled plutonium nitrate using experimental biokinetic data

Energy Technology Data Exchange (ETDEWEB)

Birchall, A.; Bailey, M.R.; Jarvis, N.S. [National Radiological Protection Board, Chilton (United Kingdom)

1995-12-31

This paper describes the new ICRP respiratory tract model with particular reference to inhaled plutonium nitrate. The model is used to determine the absorption rates to blood for plutonium nitrate which when combined with the plutonium excretion functions were used to predict urinary excretion in man. The implications of the new model for radiological protection are discussed. (UK).

Potential impacts of ICRP 60 and 61 on transportation

International Nuclear Information System (INIS)

Rawl, R.R.

1992-01-01

The International Commission on Radiological Protection (ICRP) has issued its ''1990 Recommendations of the International Commission on Radiation Protection'' that provide guidance on controlling exposure to ionizing radiation (1). The ICRP recommendations and their incorporation into the International Atomic Energy Agency's (IAEA) ''Basic Safety Standards,'' Safety Series No. 9, provide the basis on which the IAEA ''Regulation for the Safe Transport of Radioactive Materials,'' Safety Series No. 6, are built. The transportation regulations are developed to ensure safety during the movement of radioactive materials and to provide reasonable assurance the transportation activities comply with the basic radiation protection principles of Safety Series No. 9. During the 1985 revision of the IAEA transport regulations, a comprehensive model was developed to derive Type A (non-accident resistant) package contents limits that were consistent with Safety Series No.9 and, consequently, the earlier ICRP recommendations (2). Now that ICRP 60 has been published, the IAEA and Member States are faced with the task of evaluating how the transport regulations need to be revised to conform with the new recommendations. Several potentially significant issues need to be addressed to determine whether the old linkages between the recommendations and the transport regulations require modification. This paper addresses the issues that arise from the revisions to the ICRP recommendations and how the transportation regulations may be affected

Pregnancy and medical irradiation. ICRP-84; Embarazo e irradiacion medica. ICRP-84

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

A translation to Spanish of the ICRP document number 84. The exposure to ionising radiation of pregnant patients and radiation workers is a relevant subject in radiation protection, concerning not only the prevention but also the estimation of the associated risks. Great anxiety and unnecessary termination of pregnancies may be the consequences of the lack of correlation between the perception of risks by the pregnant woman and the involved professionals and their real magnitude. The International Commission on Radiation Protection has edited in 2000 the document ICRP 84 'Pregnancy and Medical Irradiation', addressed to medical and sanitary personnel. This document has been written as a practical guide which describes the effects of prenatal exposure to ionising radiation , the dose-thresholds and their relationship with the gestational age. It includes occupationally exposed women, patients undergoing medical procedures and public members. Most of diagnostic procedures properly done do not imply induction of deterministic effects in embryo/fetus. Therapeutical procedures could be associated with significant risks of deterministic effects. Childhood cancer induction is an stochastic effect without threshold and every 'in utero' exposure will increase their probability. With the aim of facilitating the diffusion of this document in the Ibero-American community , the Argentine Society of Radiation Protection (SAR) and the Spanish Society of Radiation Protection (SEPR) have worked together to producing a spanish version of ICRP84 , that is now presented in this publication, authorized by the ICRP.

Potential impact of ICRP-30 on the calculated risk from waste repositories

International Nuclear Information System (INIS)

Croff, A.G.

1981-01-01

As a result of the large body of information that has been gathered since ICRP-2 was published (1959), the ICRP has undertaken the task of updating its radiation protection guidance. This update involves revision of the primary radiation guidance as well as the recalculation of intake limits (ICRP-30) based on update biological models, updated nuclide decay schemes, and a new method accounting for simultaneous dose to more than one organ. A detailed analysis of the impacts of ICRP-30 on waste repository safety and risk analyses would require an extensive and detailed study that has not yet been undertaken. Nevertheless, it is possible to identify, in an approximate manner, the impact of using ICRP-30 instead of 10 CFR 20/ICRP-2 in calculating the risk from radioactive repositories. Toward this end, the numerical guidance of ICRP-30 has been obtained and converted into RCG values for the general public using the same methods that were employed in deriving 10 CFR 20. The conversion was cross-checked by comparing 10 CFR 20 and ICRP-30-based values that were known to have remained the same. The most restrictive ICRP-30 RCGs were incorporated into the ORIGEN2 computer code, which was then used to calculate the toxicity of some radioactive materials of interest in waste repository considerations. As a basis for discussion, the toxicities of the spent fuel from a PWR and of the uranium ore required to make the fuel are given for both the 10 CFR 20 and ICRP-30-based RCGs. As is evident, the use of the revised RCGs reduces the toxicity of the spent fuel at times less than 100 years and increases the toxicity at times thereafter

Dosimetric Significance of the ICRP's Updated Guidance and Models, 1989-2003, and Implications for U.S. Federal Guidance

Energy Technology Data Exchange (ETDEWEB)

Leggett, R.W.

2003-09-10

Over the past two decades the U.S. Environmental Protection Agency (EPA) has issued a series of Federal guidance documents for the purpose of providing the Federal and State agencies with technical information to assist their implementation of radiation protection programs. Currently recommended dose conversion factors, annual limits on intake, and derived air concentrations for intake of radionuclides are tabulated in Federal Guidance Report No. 11 (FGR 11), published in 1988. The tabulations in FGR 11 were based on dosimetric quantities and biokinetic and dosimetric models of the International Commission on Radiological Protection (ICRP) developed for application to occupational exposures. Since the publication of FGR 11 the ICRP has revised some of its dosimetric quantities and its models for workers and has also developed age-specific models and dose conversion factors for intake of radionuclides by members of the public. This report examines the extent of the changes in the inhalation and ingestion dose coefficients of FGR 11 implied by the updated recommendations of the ICRP, both for workers and members of the public.

Combline antenna modeling for plasma heating

International Nuclear Information System (INIS)

Nelson, S.D.; Kamin, G.; Van Maren, R.; Poole, B.; Moeller, C.; Phelps, D.

1996-01-01

The combline antenna for plasma heating, as proposed by General Atomics(1), has unique potential for solving many plasma drive problems. The benefit of the combline design is the utilization of the coupling between elements that avoids a more cumbersome multidrive system. This design is being investigated using computational EM modeling codes in the 100 endash 400 MHz band using resources at General Atomics and LLNL. Preliminary experimental results, using a combline mockup, agree well with 3D modeling efforts including resonant frequency alignment and amplitudes. These efforts have been expanded into an endeavor to optimize the combline design using both time and frequency domain codes. This analysis will include plasma coupling but to date has been limited to antenna effects. The combline antenna system is modeled in 3D using a combination of computational tools in the time domain, for temporal feature isolation purposes, and in the frequency domain, for resonant structure analysis. Both time and frequency domain modeling details include the Faraday shield elements, the strap elements, and the feed structure. copyright 1996 American Institute of Physics

On a mechanism of antenna phasing effect on impurity production during ICRF plasma heating

International Nuclear Information System (INIS)

Chechkin, V.V.; Grigor'eva, L.I.

1990-01-01

An appreciable reduction of the metal impurity in flux and a decrease in SOL plasma parameter disturbance occure during ICRP heating in some tokamaks when toroidally adjacent antennae are driven in anti-phase. Also cancelled are low-frequency electric field fluctuations arising in the sheaths and the associated charged particle flux fluctuations. 24 refs.; 7 figs

ICRP - history and developments

International Nuclear Information System (INIS)

Lokan, K.H.

1990-01-01

A brief history is presented of the evolution of radiation protection concepts, largely through the activities of the International Commission on Radiological Protection and their adoption in Australia by the National Health and Medical Research Council. Changes which have taken place since the preparation of the Code of Practice for Radiation Protection in the Mining and Milling of Radioactive Ores (1980) are described, and likely future directions in radiation protection are suggested. A list of the ICRP publications since ICRP-26 is provided. 4 refs

1990 recommendations of ICRP

International Nuclear Information System (INIS)

Clarke, R.H.

1991-01-01

The Main Commission of ICRP finalised its new recommendations during its November 1990 meeting. The recommendations will appear in the Annals of the ICRP in 1991 as Publication 60. This paper represents a personal summary of these recommendations. It covers the basic biological risk estimates and the conceptual framework of the system of radiological protection, the definition of radiation detriment and its use both in the definition of radiation quantities and in the establishment of the dose limits adopted by the Main Commissions. (author)

ICRP guidance on radioactive waste disposal

International Nuclear Information System (INIS)

Cooper, J.R.

2002-01-01

The International Commission on Radiological Protection (ICRP) issued recommendations for a system of radiological protection in 1991 as the 1990 Recommendations. Guidance on the application of these recommendations in the general area of waste disposal was issued in 1997 as Publication 77 and guidance specific to disposal of solid long-lived radioactive waste was issued as Publication 81. This paper summarises ICRP guidance in radiological protection requirements for waste disposal concentrating on the ones of relevance to the geological disposal of solid radioactive waste. Suggestions are made for areas where further work is required to apply the ICRP guidance. (author)

Review of ICRP recommendations

International Nuclear Information System (INIS)

Goldfinch, E.P.

1987-01-01

Events in both the scientific world and in the public domain have added pressure to review the recommendations of the ICRP on which radiation protection legislation in most countries is founded. A brief editorial pleads for clarity in ICRP recommendations, suggests the use solely of cumulative with age individual occupational dose limits, suggests that collective doses including both occupational and to the public should be kept as low as reasonably achievable, judged on quantitative economic grounds, and suggests the setting of a probability for serious accidents which may be disregarded in planning. (UK)

Radon dosimetry for workers: ICRP's approach

International Nuclear Information System (INIS)

Marsh, James W.; Laurier, Dominique; Tirmarche, Margot

2017-01-01

The International Commission on Radiological Protection (ICRP) has recently published two reports on radon exposure; Publication 115 on lung cancer risks from radon and radon progeny and Publication 126 on radiological protection against radon exposure. A specific graded approach for the control of radon in workplaces is recommended where a dose assessment is required in certain situations. In its forthcoming publication on Occupational Intakes of Radionuclides (OIR) document, Part 3, effective dose coefficients for radon and thoron will be provided. These will be calculated using ICRP reference biokinetic and dosimetric models. Sufficient information and dosimetric data will be given so that site-specific dose coefficients can be calculated based on measured aerosol parameter values. However, ICRP will recommend a single dose coefficient of 12 mSv per working level month (WLM) for inhaled radon progeny to be used in most circumstances. This chosen reference value was based on both dosimetry and epidemiological data. In this paper, the application and use of dose coefficients for workplaces are discussed including the reasons for the choice of the reference value. Preliminary results of dose calculations for indoor workplaces and mines are presented. The paper also briefly describes the general approach for the management of radon exposure in workplaces based both on ICRP recommendations and the European directive (2013/59/EURATOM). (authors)

A method for rapid estimation of internal dose to members of the public from inhalation of mixed fission products (based on the ICRP 1994 human respiratory tract model for radiological protection)

International Nuclear Information System (INIS)

Hou Jieli

1999-01-01

Based on the computing principle given in ICRP-30, a method had been given by the author for fast estimating internal dose from an intake of mixed fission products after nuclear accident. Following the ICRP-66 Human respiratory tract model published in 1994, the method was reconstructed. The doses of 1 Bq intake of mixed fission products (its AMAD = 1 μm, decay rate coefficient n = 0.2∼2.0) during the period of 1∼15 d after an accident were calculated. It is lower slightly based on ICRP 1994 respiratory tract model than that based on ICRP-30 model

Respectful doubts on the new ICRP recommendations

International Nuclear Information System (INIS)

Diaz de la Cruz, F.

1992-01-01

The admiration and deference an International Organization, as ICRP, deserves not only by its altruistic mission but also by the eminent and distinguished scientists who work for it, in some way 'dazzles' to simple students of its theories and, in some way 'force' us to accept, sometimes without any critical, serious and previous meditation, its recommendations. But it is not the bad thing this kind of 'blindness' we have before the almighty ...ICRP dixit..., the worst thing is that non-specialist and non-specialized persons believe as 'dogmas' and 'axioms' the ICRP recommednations and make of them legal dispositions through standards and regulations. Standards an regulations which can frustate an industrial or any other type of peaceful nuclear activity due to the economic or the social reasons derived from ICRP recommendations. The inflexibility (weakened in the arguments but strengthened in the recommendations) of this influent Organism on the 'linearity without threshold' in the dose-effect relationship and the compromises of the International Labor Organization (ILO) with respect ICRP recommedations provole irrational, ilogical and non desirable answers. (author)

Radiobiological basis of radiation protection and ICRP 2007 general recommendations

International Nuclear Information System (INIS)

Rao, B.S.

2014-01-01

The ICRP 2007 General Recommendations are based on the detailed review of the new information on the biological effects and risk evaluation done during the last decade. Most of this information reinforces the validity of earlier findings. Since the publication of ICRP 60 general recommendations in 1991(ICRP 1991b), sufficient new information on the health effects of ionizing radiations has accrued based on radiobiological and epidemiological studies (UNSCEAR 2000, ICRP Publication 99). There is an improvement in understanding the mechanistic aspects of the induction of radiation damage at cellular level. Biophysical studies based on Monte Carlo track structure codes have provided information on the nature of critical damage to DNA leading to the radiation effects at cellular level. Experimental work with model animal systems has provided information on the role of post irradiation repair processes and the genes influencing the process of radiation carcinogenesis. Longer follow up of A-Bomb survivors of Hiroshima and Nagasaki now provides a more reliable risk estimate based on the cancer incidence data and also a better model for the transfer of risk among different populations with varying frequency of background incidence. At present it is clear that the breast cancer contributes substantially to the radiation risk and provides quantitative risk estimates for brain and salivary glands. In the light of the new information, Tissue Weighting factors (WT) have been revised

Potential impacts of ICRP 60 and 61 on the transportation regulations

International Nuclear Information System (INIS)

Rawl, R.R.; Eckerman, K.F.; Wangler, M.E.; Punch, F.; Carriker, A.W.

1992-01-01

The International Commission on Radiation Protection (ICRP) has been providing recommendations for limitations on radiation exposure for decades. The ICRP recommendations address ionizing radiation and are concerned with protecting humans from its effects. These recommendations assist regulatory and advisory agencies in establishing and promulgating national regulations and practices in radiation Protection. Most countries have incorporated at least some aspect of the recommendations in their regulations since about 1956 when the first basic prowdon standard was Published in ICRP 2. Since that time ICRP has issued two major revisions to the recommendations. ICRP 26 was published in 1977 and ICRP 60 was published in 1991. These last two publications have companion works, ICRP 30 atid ICRP 61, that contain Annual Limits of Intake (ALI) for radiation workers. This report discusses the impacts of ICRP 60 and 61 on transport regulations

The ICRP 2007 recommendations

International Nuclear Information System (INIS)

Streffer, C.

2007-01-01

The last comprehensive International Commission on Radiological Protection (ICRP) recommendations have been published in 1991(1). Since that time new data in physics and biology that are relevant for radiological protection have appeared in the scientific literature. Also, the general thinking about safety standards at the workplace as well as for the protection of the public has developed. Thus, a review of the recommendations is needed. However, as the present standards have worked well, these new recommendations should build on the present ones. Only a process of further development should take place allowing for the following key points: - new biological and physical information and trends in the setting of safety standards; - improvement in the presentation of the recommendations; as much stability in the recommendations as is consistent with the new information and environmental aspects will be included. The fundamental principles of radiological protection will remain the same as they have been described in ICRP publication 60(1): Justification: Actions involving new exposures or changes in exposures of individuals have to be justified in advance. A positive net benefit must result. Optimisation: Exposures should be as low as reasonably achievable and should be optimised in relation to with dose constraints. Dose limits: The values will not to be changed from Publication 60. Dose constraints: Development of the concept proposed in Publication 60 will be explained. The ICRP Committees have prepared foundation documents in the fields for which they are responsible and their members have the corresponding expertise. These foundation documents will support the decisions and explain the various statements of the Main Commission in a broader sense. Some of them will be published as Annexes to the recommendations (Annex A: Biological and Epidemiological Information on Health Risks Attributable to Ionising Radiation; Annex B: Quantities used in Radiological

The ICRP 2007 recommendations

Energy Technology Data Exchange (ETDEWEB)

Streffer, C. [Chairman of ICRP Committee 2, Institute of Science and Ethics, University Duisburg-Essen, 45117 Essen (Germany)

2007-07-01

The last comprehensive International Commission on Radiological Protection (ICRP) recommendations have been published in 1991(1). Since that time new data in physics and biology that are relevant for radiological protection have appeared in the scientific literature. Also, the general thinking about safety standards at the workplace as well as for the protection of the public has developed. Thus, a review of the recommendations is needed. However, as the present standards have worked well, these new recommendations should build on the present ones. Only a process of further development should take place allowing for the following key points: - new biological and physical information and trends in the setting of safety standards; - improvement in the presentation of the recommendations; as much stability in the recommendations as is consistent with the new information and environmental aspects will be included. The fundamental principles of radiological protection will remain the same as they have been described in ICRP publication 60(1): Justification: Actions involving new exposures or changes in exposures of individuals have to be justified in advance. A positive net benefit must result. Optimisation: Exposures should be as low as reasonably achievable and should be optimised in relation to with dose constraints. Dose limits: The values will not to be changed from Publication 60. Dose constraints: Development of the concept proposed in Publication 60 will be explained. The ICRP Committees have prepared foundation documents in the fields for which they are responsible and their members have the corresponding expertise. These foundation documents will support the decisions and explain the various statements of the Main Commission in a broader sense. Some of them will be published as Annexes to the recommendations (Annex A: Biological and Epidemiological Information on Health Risks Attributable to Ionising Radiation; Annex B: Quantities used in Radiological

Remarks of the SFRP working group about ICRP recommendations

International Nuclear Information System (INIS)

Schieber, C.; Cordoliani, Y.S.

2005-01-01

Remarks of the SFRP working group about ICRP recommendations. The International Commission on Radiological Protection has proposed last summer on its Web site the draft text of the 2005 ICRP recommendations for consultation. As it was done for the previous drafts, the French Society for Radiation Protection, has sent his comments to the ICRP, through a specific working group. The text sent to the ICRP is presented here to the readers of the SFRP's Journal. (author)

ICRP Recommendations to the Protection of People Living in Long-Term Contaminated Areas ICRP publication 111 in brief

International Nuclear Information System (INIS)

Salama, S.; Gomaa, M. A.; Rashad, S.

2013-01-01

The main aim of the present study is to through some lights on ICRP free release publication at 4 April 2011-Internationally Known as ICRP publication 111. The title of the publication is (application of the commission's recommendations to the protection of people living in long-term contaminated areas after a nuclear accident or a radiation emergency). Nuclear accidents or a radiation emergency may cause contamination. The contamination may be spread on a large area. There are people living in these areas. For many factors the people refuse to leave their homes. They want to stay along their life as in the case of the normal conditions. So, it is important to facilitate their stay and make it safe. This is not easy. But it is possible without neglect the radiation hazard. The radiation hazard is effective on the life fields. It is harmful in plants, animals, foods, water, milk and the buildings it self. With considering the radiological protection principles the living of the people for a long time could be a fact of the life and will be more easy and safe. Optimization principle has priority to apply. This publication achieves these purposes.The ICRP-111 is translated into Arabic at August 2012. This work is a continuation of the efforts series to translate some of the most important of the ICRP radiological protection references into the Arabic; aiming to maximize the benefit. The previous translations include, ICRP-105 (radiation protection in medicine) and ICRP -113 (education and training in radiological protection for diagnostic and interventional procedures).

Workers and the ICRP recommendations

International Nuclear Information System (INIS)

Zerbib, J.C.

1979-01-01

In both the preparation and the application of the recommendations presented by the ICRP one important voice has been absent: that of the workers in the nuclear industry. A large number of specialists are studying their situation from all points of view, in their different capacities as workers, consumers and male or female members of the public, but this extensive study is being done without consulting them, without their opinion even being asked for. The paper discusses such deficiencies, in particular all those aspects which distinguish these recommendations from a legal text. The lack of conciseness in the definition of the limit which the average annual dose to a large group of workers must not exceed (500 mrad) is considered. The possibility of a large number of workers being exposed for a long period is not acceptable if the decision is left to the manager of a nuclear facility alone. Cost-benefit analysis, as it is described in the ICRP text, cannot be considered to provide credible protection from the point of view of workers. Moreover, the various ICRP recommendations fail to mention such important matters as allowance for low-dose effects, disparities in the social security coverage offered to various categories of workers in the event of occupational illness, and the increasing use of migrant workers for difficult decontamination and maitenance tasks. At a time when it is thought that nuclear technology can be standardized, the French Democratic Labour Confederation (CFDT) expresses its fears concerning the practical application of the ICRP recommendations; for example, the text of ICRP Publication 26 has not yet been translated into French, but Euratom has already proposed directives for its application in Member States

Intercomparison of concepts in ICRP 60 and ICRP 103

International Nuclear Information System (INIS)

Youssif, B. E.

2013-04-01

The ICRP has produced recommendation three times in the last 30 years, In 2007, the ICRP approved new recommendations, These revised Recommendations for a System of Radiological Protection formally replace the Commission’s previous, 1990, Recommendations; and updated, consolidated, and developed the additional guidance on the control of exposure from radiation sources issued since 1990. The purpose of this study is to highlight and review some of major changes that have taken place. To compare between the 1990 recommendations (ICRP 60) and the 2007 recommendations (ICRP 103) according to radiological studies updated. The 2007 Recommendations update the radiation and tissue weighting factors in the quantities equivalent and effective dose .The major differences for tissue weighting factors increased by about a factor of two for breast and remainder tissues. Whilst the gonads are decreased by about a factor of two. The major change of WR for protons is a reduction from five to two reflecting a better understanding of the dosimetry of proton. For neutrons there is a reduction of WR of about a factor of two for thermal neutrons. An update on the radiation detriment has been made; based on the latest available scientific information of the biology and physics of radiation exposure. The detrimental nominal risk coefficient in 2007 Recommendations is lower by about 25% compared to 1990 Recommendations. Publication 103 maintains the Commission’s three fundamental principles of radiological protection, namely justification, optimisation, and the application of dose limits, clarifying how they apply to radiation sources delivering exposure and to individuals receiving exposure. The 2007 Recommendations evolve from the previous process-based protection approach using practices and interventions by moving to an approach based on the exposure situation. The recommendations recognise planned, emergency, and existing exposure situations, and apply the fundamental principles

Simulation of The ICRP-30 Dosimetric Model for the Respiratory Tract

International Nuclear Information System (INIS)

Giaddui, T.; Atia, M. A.

2004-01-01

Matlab was used to write a simulation program (ACID1) to simulate the ICRP-30 dosimetric model for the respiratory tract. The program (a new version of the one presented at the sixth Arab conference held in Cairo 2002) calculates a series of dosimetric quantities for the reference man as a result of the inhalation of any radionuclide. The program also plots the variation of activity with time for all organs and provided with a graphical user interface to make it friendly user. The results obtained by this program was compared with similar results obtained by other source and found to be very close. (Authors)

Modeling and Optimizing Antennas for Rotational Spectroscopy Applications

Directory of Open Access Journals (Sweden)

Z. Raida

2006-12-01

Full Text Available In the paper, dielectric and metallic lenses are modeled and optimized in order to enhance the gain of a horn antenna in the frequency range from 60 GHz to 100 GHz. Properties of designed lenses are compared and discussed. The structures are modeled in CST Microwave Studio and optimized by Particle Swarm Optimization (PSO in order to get required antenna parameters.

Modelling of UWB Antenna Perturbed by Human Phantom in Spherical Harmonics Space

DEFF Research Database (Denmark)

Mhedhbi, Meriem; Avrillon, Stephane; Pedersen, Troels

2014-01-01

is attractive for simulation purposes. We propose a simple model for the spherical harmonics coefficients allowing to predict the antenna behavior perturbed by a human phantom. The model is based on knowledge of the spherical harmonic coefficients of antenna in free space and the antenna-phantom distance.......In this paper we study how the antenna radiation pattern is perturbed in the presence of a human phantom in terms of changes in the coefficients of the spherical harmonic antenna representation. The spherical harmonic basis allows for a compact representation of the antenna pattern which...

Potential impacts of ICRP 60 and 61 on transportation

International Nuclear Information System (INIS)

Rawl, Richard R.

1992-01-01

The International Commission on Radiological Protection (IGRP) has issued its '1990 Recommendations of the International Commission on Radiation Protection' that provide guidance on controlling exposure to ionizing radiation. The ICRP recommendations and their incorporation into the International Atomic Energy Agency's (IAEA) 'Basic Safety Standards', Safety Series No. 9, provide the basis on which the IAEA 'Regulations for the Safe Transport of Radioactive Materials', Safety Series No. 6, are built. The transportation regulations are developed to ensure safety during the movement of radioactive materials and to provide reasonable assurance the transportation activities comply with the basic radiation protection principles of Safety Series No. 9. During the 1985 revision of the IAEA transport regulations, a comprehensive model was developed to derive Type A (non-accident resistant) package contents limits that were consistent with Safety Series No. 9 and, consequently, the earlier ICRP recommendations. Now that ICRP 60 has been published, the IAEA and Member States are faced with the task of evaluating how the transport regulations need to be revised to conform with the new recommendations. Several potentially significant issues need to be addressed to determine whether the old linkages between the recommendations and the transport regulations require modification. This paper addresses the issues that arise from the revisions to the ICRP recommendations and how the transportation regulations may be affected. (author)

The recommendations of ICRP Publication 111 in the light of the ICRP dialogue initiative in Fukushima.

Science.gov (United States)

Lochard, J

2016-12-01

Publication 111, published by the International Commission on Radiological Protection (ICRP) in 2009, provided the first recommendations for dealing with the long-term recovery phase after a nuclear accident. Its focus is on the protection of people living in long-term contaminated areas after a nuclear accident, drawing on the experience of the Belarus population, Cumbrian sheep farmers in the UK, and Sami reindeer herders in Norway affected by the fallout from Chernobyl. The ICRP dialogue initiative in Fukushima confirmed what had been identified after Chernobyl, namely the very strong concern for health, particularly that of children, loss of control over everyday life, apprehension about the future, disintegration of family life and of the social and economic fabric, and the threat to the autonomy and dignity of affected people. Through their testimonies and reflections, the participants of the 12 dialogue meetings shed light on this complex situation. The ICRP dialogue initiative also confirmed that the wellbeing of the affected people is at stake, and radiological protection must focus on rehabilitation of their living conditions. The challenge is to incorporate the important clarifications resulting from the ICRP dialogue initiative into the updated version of Publication 111 that is currently in development. This paper does not necessarily reflect the views of the International Commission on Radiological Protection.

Hybrid pregnant reference phantom series based on adult female ICRP reference phantom

Science.gov (United States)

Rafat-Motavalli, Laleh; Miri-Hakimabad, Hashem; Hoseinian-Azghadi, Elie

2018-03-01

This paper presents boundary representation (BREP) models of pregnant female and her fetus at the end of each trimester. The International Commission on Radiological Protection (ICRP) female reference voxel phantom was used as a base template in development process of the pregnant hybrid phantom series. The differences in shape and location of the displaced maternal organs caused by enlarging uterus were also taken into account. The CT and MR images of fetus specimens and pregnant patients of various ages were used to replace the maternal abdominal pelvic organs of template phantom and insert the fetus inside the gravid uterus. Each fetal model contains 21 different organs and tissues. The skeletal model of the fetus also includes age-dependent cartilaginous and ossified skeletal components. The replaced maternal organ models were converted to NURBS surfaces and then modified to conform to reference values of ICRP Publication 89. The particular feature of current series compared to the previously developed pregnant phantoms is being constructed upon the basis of ICRP reference phantom. The maternal replaced organ models are NURBS surfaces. With this great potential, they might have the feasibility of being converted to high quality polygon mesh phantoms.

Calculation of local skin doses with ICRP adult mesh-type reference computational phantoms

Science.gov (United States)

Yeom, Yeon Soo; Han, Haegin; Choi, Chansoo; Nguyen, Thang Tat; Lee, Hanjin; Shin, Bangho; Kim, Chan Hyeong; Han, Min Cheol

2018-01-01

Recently, Task Group 103 of the International Commission on Radiological Protection (ICRP) developed new mesh-type reference computational phantoms (MRCPs) for adult males and females in order to address the limitations of the current voxel-type reference phantoms described in ICRP Publication 110 due to their limited voxel resolutions and the nature of the voxel geometry. One of the substantial advantages of the MRCPs over the ICRP-110 reference phantoms is the inclusion of a 50-μm-thick radiosensitive skin basal-cell layer; however, a methodology for calculating the local skin dose (LSD), i.e., the maximum dose to the basal layer averaged over a 1-cm2 area, has yet to be developed. In the present study, a dedicated program for the LSD calculation with the MRCPs was developed based on the mean shift algorithm and the Geant4 Monte Carlo code. The developed program was used to calculate local skin dose coefficients (LSDCs) for electrons and alpha particles, which were then compared with the values given in ICRP Publication 116 that were produced with a simple tissue-equivalent cube model. The results of the present study show that the LSDCs of the MRCPs are generally in good agreement with the ICRP-116 values for alpha particles, but for electrons, significant differences are found at energies higher than 0.15 MeV. The LSDCs of the MRCPs are greater than the ICRP-116 values by as much as 2.7 times at 10 MeV, which is due mainly to the different curvature between realistic MRCPs ( i.e., curved) and the simple cube model ( i.e., flat).

Fundamental ICRP recommendations at the start of the 21st century: status of the revision of ICRP publication 60

International Nuclear Information System (INIS)

Valentin, J.

2002-01-01

The basic recommendations of the International Commission on Radiological Protection, ICRP, are either re-stated or revised at intervals of about 15 years, most recently in ICRP Publication 60, adopted in 1990. ICRP plan to issue its next recommendations around 2005. Through extensive consultation, the active participation of the radiological protection community was recruited already at the conceptual stage. Based on the vast input received, ICRP is currently preparing draft recommendations. These are likely to emphasise egalitarian values more than utilitarian ones, to be holistic rather than anthropocentric, and to be formatted as a relatively concise set of actual recommendations underpinned by separate publications with more detail. The draft will again be circulated worldwide and comments will be discussed in 2004 with a view to approval of the recommendations in 2005 and publication in 2005 or 2006. Thus, integration into legislation would be possible sometime between 2006 and 2010, say. (orig.) [de

Integrating socio-economical dimensions in the ICRP cost-benefit model (a theoretical approach)

International Nuclear Information System (INIS)

Lochard, Jacques.

1981-09-01

This report aims at analysing, from a methodological point of view, the main problems associated with the integration of socio-economical dimensions in the cost-benefit model recommended by the ICRP in its publication no. 26. After recalling the basic principles of cost-benefit analysis, the elements to be retained in the objective function characterizing the analysis, and the question of the social benefit definitions are discussed. The theory of social surplus with an illustration taken from the radiological protection field is presented [fr

Adaptation of the ICRP models for the Techa River populations to estimate in utero and postnatal haemopoietic tissue doses from ingested strontium isotopes

International Nuclear Information System (INIS)

Shagina, Natalia; Tolstykh, Evgenia; Degteva, Marina; Fell, Tim; Harrison, John

2008-01-01

Full text: Reliable estimation of tissue doses for exposed individuals is very important in epidemiological studies. Long-term cohort studies of the Techa River populations exposed in the early 1950s due to releases of liquid radioactive wastes from the Mayak plutonium production facility (Southern Urals, Russia) are unique in allowing the quantification of risks from low-level chronic exposure of the general population and providing information on risks for persons exposed in utero. Strontium isotopes were the most important contributors to haemopoietic tissue doses for people living in the riverside settlements. Large-scale monitoring of the exposed population has provided a comprehensive database, including post mortem and in vivo measurements of 90 Sr in bones and whole body, for use in the estimation of doses. The International Commission on Radiological Protection (ICRP) has published biokinetic and dosimetric models for the calculation of doses to members of the public, including doses from in utero exposures and from intakes with breast milk. However, the ICRP models as applied to Sr required modification to provide best estimates of doses to Techa River residents. Adaptations were made to the ICRP model for Sr in children and adults to take account of population-specific features relating to bone mineral turnover and to model age and gender differences in strontium retention. Refinements in the ICRP model for Sr uptake and retention in the fetus were made to improve the treatment of discrimination against Sr, relative to Ca, in transfer from maternal to foetal blood and to take account of population-specific data on the calcium content of the maternal and fetal skeleton. Modification of the ICRP model for Sr transfer in breast-milk included adaptations relating to changes in maternal mineral metabolism during lactation and consideration of population-specific features of breast feeding in the rural population. The improved models were successfully

International radiation protection recommendations. Five years experience of ICRP Publication 26

International Nuclear Information System (INIS)

Lindell, B.; Beninson, D.; Sowby, F.D.

1983-01-01

The International Commission on Radiological Protection has issued radiation protection recommendations since 1928. The latest set of basic recommendations was adopted by the Commission on 17 January 1977, and subsequently published as ICRP Publication 26. This document has met with a wider interest than any of the previous ICRP recommendations. It has been considered to mark a radical change in the protection policy advocated by ICRP. It is not often appreciated that recommendations which are believed to be 'new' in ICRP Publication 26 had already been made in ICRP Publication 9 more than ten years earlier. In any event, ICRP Publication 26 has had a substantial impact on regulatory work in countries all over the world. It forms the basis for the Basic Safety Standards of the international organizations IAEA, ILO, OECD/NEA and WHO. The paper refers to the experience gained in using the new ICRP recommendations over the five years that have passed since ICRP Publication 26 was adopted and discusses some of the problems that have arisen in the practical application of the new recommendations in various countries. (author)

An Optimal Electric Dipole Antenna Model and Its Field Propagation

Directory of Open Access Journals (Sweden)

Yidong Xu

2016-01-01

Full Text Available An optimal electric dipole antennas model is presented and analyzed, based on the hemispherical grounding equivalent model and the superposition principle. The paper also presents a full-wave electromagnetic simulation for the electromagnetic field propagation in layered conducting medium, which is excited by the horizontal electric dipole antennas. Optimum frequency for field transmission in different depth is carried out and verified by the experimental results in comparison with previously reported simulation over a digital wireless Through-The-Earth communication system. The experimental results demonstrate that the dipole antenna grounding impedance and the output power can be efficiently reduced by using the optimal electric dipole antenna model and operating at the optimum frequency in a vertical transmission depth up to 300 m beneath the surface of the earth.

Accurate Antenna Models in Ground Penetrating Radar Diffraction Tomography

DEFF Research Database (Denmark)

Meincke, Peter; Kim, Oleksiy S.

2002-01-01

are modeled by their plane-wave receiving and transmitting spectra. We find these spectra numerically for a resistively loaded dipole using the method of moments. Also, we illustrate, through a numerical example, the importance of taking into account the correct antenna pattern in GPR diffraction tomography.......Linear inversion schemes based on the concept of diffraction tomography have proven successful for ground penetrating radar (GPR) imaging. In many GPR surveys, the antennas of the GPR are located close to the air-soil interface and, therefore, it is important to incorporate the presence...... of this interface in the inversion scheme (see Hansen, T.B. and Meincke Johansen, P., IEEE Trans. Geoscience and Remote Sensing, vol.38, p.496-506, 2000). Hansen and Meincke Johansen modeled the antennas as ideal (Hertzian) electric dipoles. Since practical GPR antennas are not ideal, it is of interest...

The revised International Commission on Radiological Protection (ICRP) dosimetric model for the human respiratory tract

International Nuclear Information System (INIS)

Bair, W.J.

1992-05-01

A task group has revised the dosimetric model of the respiratory tract used to calculate annual limits on intake of radionuclides. The revised model can be used to project respiratory tract doses for workers and members of the public from airborne radionuclides and to assess past exposures. Doses calculated for specific extrathoracic and thoracic tissues can be adjusted to account for differences in radiosensitivity and summed to yield two values of dose for the respiratory tract that are applicable to the ICRP tissue weighted dosimetry system

Key implications of the new ICRP recommendations: contribution of the C.R.P.P.H. expert group on the implications of ICRP recommendations (E.G.I.R.)

International Nuclear Information System (INIS)

Lazo, T.

2003-01-01

The International Commission of Radiological Protection (ICRP) has embarked on a broad programme of consultation in order to collect concepts, ideas and views regarding how radiological protection should be managed at the start of the 21 st century. The results of this consultation will be a new set of comprehensive ICRP recommendations, updating and consolidating ICRP publication 60 and all subsequent ICRP recommendations. It is expected that the new ICRP general recommendations will be published in 2005 with additional more detailed building block recommendations being published in subsequent years. (N.C.)

A stake holder dialogue on the implications of the ICRP recommendations

International Nuclear Information System (INIS)

2008-01-01

Since its inception the NEA Committee on Radiation Protection and Public Health (CRPPH) has been involved in the assessment and implementation of the recommendations of the International Commission on Radiological Protection (ICRP). The development of new general ICRP recommendations, to replace those of the 1990 ICRP Publication 60, was thus of great interest to the NEA and its member countries. As a result, the NEA initiated a process of interaction and dialogue with the ICRP to ensure that the views and concerns of NEA member countries could be voiced and appropriately addressed in the new ICRP recommendations. The new ICRP recommendations were approved by the ICRP Main Commission in March 2007, by which point the NEA had sponsored 7 international conferences and produced 13 publications on the subject. This report is the summary of the three international dialogue conferences (held in Tokyo, 5-6 July 2006, Washington, DC, 28-29 August 2006, and Prague, 24-25 October 2006) that were organised to provide the ICRP with feedback regarding the June 2006 draft of its new recommendations. It includes a presentation of the key points of the draft recommendations, a summary of the suggestions made during the three conferences, and an assessment of the significant evolution that has been seen in the ICRP presentation of its draft recommendations over the course of the conference series. (authors)

Conversion of ICRP male reference phantom to polygon-surface phantom

Science.gov (United States)

Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong; Jeong, Jong Hwi

2013-10-01

The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (original ICRP reference phantoms, it is believed that the polygon-surface version of ICRP reference phantoms properly developed will not only provide the same or similar dose values (say, difference <5 or 10%) for highly penetrating radiations, but also provide correct dose values for the weakly penetrating

Comparison of the U-233 dog data of Stevens et al. with uranium retention functions in ICRP Publication 30 and a 3-compartment mammillary model for uranium

International Nuclear Information System (INIS)

Bernard, S.R.

1983-01-01

Stevens measured the distribution, retention, and excretion of U-233 in seven beagles each given a single injection of U-233 citrate [2.8 μCi/kg U-233 (VI) (approx.3 mg/dog)]. These data, when plotted together with results obtained with the ICRP (Pub. 30) retention functions for purposes of comparison, are seen to differ only slightly from the ICRP-30 model. The number of transformations in the body, over a fifty-year period agree within a factor of 2. A three-compartment mammillary model has been parameterized from the data of Stevens by the method of Bernard. Retention in tissues of the body is represented by a linear combination of three compartments. The data plots for the dogs and ICRP-30 model will be presented and discussed together with the three compartment mammillary model for U-233 retention, distribution, and excretion. 3 figs., 2 tabs

ICRP risk assessment-another view (24 november 1986)

International Nuclear Information System (INIS)

Morgan, K.Z.

1988-01-01

Beginning in 1960 two serious radiation exposure problems (occupational exposure in uranium mines and population exposure from testing of nuclear weapons) came to the attention. One might have expected ICRP to be the first to try to reduce these exposures but it was conspicuous by its silence. In 1958 ICRP set limits of exposure for radiation workers and members of the public. Nineteen years later (1977) when it was realized that the risk of radiation induced cancer was ten to thirty times what it was estimated to be in 1958, ICRP might have been expected to recommend a significant reduction in permissible exposure levels, but to the dismay of some it increased them. It was also a great disappointment when in 1977, levels of maximum permissible concentration of radionuclides in air, water and food were increased for a large fraction of the more dangerous radionuclides. The reactor accident at Chernobyl calls for a number of new ICRP recommendations [fr

Finite difference time domain modeling of spiral antennas

Science.gov (United States)

Penney, Christopher W.; Beggs, John H.; Luebbers, Raymond J.

1992-01-01

The objectives outlined in the original proposal for this project were to create a well-documented computer analysis model based on the finite-difference, time-domain (FDTD) method that would be capable of computing antenna impedance, far-zone radiation patterns, and radar cross-section (RCS). The ability to model a variety of penetrable materials in addition to conductors is also desired. The spiral antennas under study by this project meet these requirements since they are constructed of slots cut into conducting surfaces which are backed by dielectric materials.

New Modelling Capabilities in Commercial Software for High-Gain Antennas

DEFF Research Database (Denmark)

Jørgensen, Erik; Lumholt, Michael; Meincke, Peter

2012-01-01

characterization of the reflectarray element, an initial phaseonly synthesis, followed by a full optimization procedure taking into account the near-field from the feed and the finite extent of the array. Another interesting new modelling capability is made available through the DIATOOL software, which is a new...... type of EM software tool aimed at extending the ways engineers can use antenna measurements in the antenna design process. The tool allows reconstruction of currents and near fields on a 3D surface conformal to the antenna, by using the measured antenna field as input. The currents on the antenna...... surface can provide valuable information about the antenna performance or undesired contributions, e.g. currents on a cable,can be artificially removed. Finally, the CHAMP software will be extended to cover reflector shaping and more complex materials,which combined with a much faster execution speed...

Implementation of the ICRP 2007 recommendations in Korea

International Nuclear Information System (INIS)

Cho, Kun-Woo

2008-01-01

Full text: International Commission on Radiological Protection (ICRP) is about to publish new recommendations on radiation protection. International Atomic Energy Agency (IAEA) is also under process in revising its International Basic Safety Standards (BSS) to take into account of the changes of the ICRP recommendations. As soon as the revision of the BSS is completed, Korean government is considering to implement those changes in the BSS and the ICRP recommendations into its national radiation protection laws and regulations. This paper introduces the current activities and future prospects in this matter. In the 2007 ICRP recommendations, there are some new concepts, principles and quantities such as the changes in the nominal risk coefficient for cancer and hereditary effects, new definitions on the tissue weighting factors and radiation weighting factors for neutron and proton, extended application of the dose constraints in all exposure situations in source-related radiation protection, and the introduction of new system of protection for non-human species. Based on the study carried out by KINS so far, the following points are identified as major areas that need for further in-depth review and consideration for the implementation of the ICRP 2007 recommendations into Korean radiation protection laws and regulations; changes in the radiation risk factors, radiation weighting factors and tissue weighting factors, maintenance of the ICRP 60 dose limits, practical application of the dose constraints and determination of the reference levels in many source to individual exposure relationships, change from process-based system to exposure situation-based system, strengthening of the principle of optimization in all exposure situations, system of radiation protection for the environment, practical application of the exclusion and exemption principles, active participation of the stake holders, changes in glossary etc. The study for the implementation of the ICRP

Pregnancy and medical irradiation. ICRP-84

International Nuclear Information System (INIS)

2001-01-01

A translation to Spanish of the ICRP document number 84. The exposure to ionising radiation of pregnant patients and radiation workers is a relevant subject in radiation protection, concerning not only the prevention but also the estimation of the associated risks. Great anxiety and unnecessary termination of pregnancies may be the consequences of the lack of correlation between the perception of risks by the pregnant woman and the involved professionals and their real magnitude. The International Commission on Radiation Protection has edited in 2000 the document ICRP 84 'Pregnancy and Medical Irradiation', addressed to medical and sanitary personnel. This document has been written as a practical guide which describes the effects of prenatal exposure to ionising radiation , the dose-thresholds and their relationship with the gestational age. It includes occupationally exposed women, patients undergoing medical procedures and public members. Most of diagnostic procedures properly done do not imply induction of deterministic effects in embryo/fetus. Therapeutical procedures could be associated with significant risks of deterministic effects. Childhood cancer induction is an stochastic effect without threshold and every 'in utero' exposure will increase their probability. With the aim of facilitating the diffusion of this document in the Ibero-American community , the Argentine Society of Radiation Protection (SAR) and the Spanish Society of Radiation Protection (SEPR) have worked together to producing a spanish version of ICRP84 , that is now presented in this publication, authorized by the ICRP

Application of physiological parameters of a sample of the Brazilian population in different levels of exercise, on the deposition model of the ICRP Publication 66

International Nuclear Information System (INIS)

Reis, Arlene A. dos; Cardoso, Joaquim C.S.; Lourenco, Maria C.

2005-01-01

The Human Respiratory Tract Model (HRTM) proposed by the ICRP Publication 66 accounts for the morphology and physiology of the respiratory tract. The characteristics of air drawn into the lungs and exhaled are greatly influenced by the morphology of the respiratory tract, which causes numerous changes in pressure, flow rate, direction and humidity as air moves into and out of the lungs. The model uses morphological and physiological parameters from the Caucasian man to establish deposition fractions in the respiratory tract regions. The ICRP recommends, for a reliable evaluation of the regional deposition, the use of parameters from a local population when information is available. The main purpose of this study is to verify the influence in using the morphology and physiology parameters representative of a sample of the Brazilian population, in different levels of exercise, on the deposition model of the ICRP Publication 66. The deposition model was implemented using software Excel for Windows (version 2000). The results suggest a significant variation in fractional deposition when Brazilian parameters are applied in the model. The variations are not the same for all regions of the respiratory tract and depend on levels of exercise. (author)

Time-Domain Modeling of RF Antennas and Plasma-Surface Interactions

Directory of Open Access Journals (Sweden)

Jenkins Thomas G.

2017-01-01

Full Text Available Recent advances in finite-difference time-domain (FDTD modeling techniques allow plasma-surface interactions such as sheath formation and sputtering to be modeled concurrently with the physics of antenna near- and far-field behavior and ICRF power flow. Although typical sheath length scales (micrometers are much smaller than the wavelengths of fast (tens of cm and slow (millimeter waves excited by the antenna, sheath behavior near plasma-facing antenna components can be represented by a sub-grid kinetic sheath boundary condition, from which RF-rectified sheath potential variation over the surface is computed as a function of current flow and local plasma parameters near the wall. These local time-varying sheath potentials can then be used, in tandem with particle-in-cell (PIC models of the edge plasma, to study sputtering effects. Particle strike energies at the wall can be computed more accurately, consistent with their passage through the known potential of the sheath, such that correspondingly increased accuracy of sputtering yields and heat/particle fluxes to antenna surfaces is obtained. The new simulation capabilities enable time-domain modeling of plasma-surface interactions and ICRF physics in realistic experimental configurations at unprecedented spatial resolution. We will present results/animations from high-performance (10k-100k core FDTD/PIC simulations of Alcator C-Mod antenna operation.

Application in the Nordic countries of ICRP publication 26

International Nuclear Information System (INIS)

2006-01-01

The radiation protection institutes of the five Nordic countries, Denmark, Finland, Iceland, Norway and Sweden, published in 1976 a joint report on the applicability of international radiation protection recommendations in the Nordic countries. The report was mainly based on the set of recommendations issued by the International Commission on Radiological Protection (ICRP). In the report it was stated that 'if the basic recommendations of ICRP are subsequently revised, it is the intention of the radiation protection institutes to consider equivalent changes in the recommended basis for regulatory texts and, if there is full agreement, jointly to announce changes which may be made in respect to the principles which have been recommended here'. In 1977 ICRP published its revised basic recommendations (ICRP Publication 26) which resulted from the examination of new information during the last decade and since the Commission's previous basic recommendations (ICRP Publication 9 adopted in 1965. In 1978 the representatives of the radiation protection institutes of the Nordic countries agreed at their meeting in Helsinki to prepare a joint policy document on the application of the revised ICRP recommendations in the Nordic countries. In common with the previous joint report of the Nordic radiation protection institutes of 1976 the present recommendations deal only with ionizing radiation. In the new recommendations ICRP has more clearly than in the previous recommendations systematized the basic principles in radiation protection by crystallizing its system of dose limitation in three main points: a) no practice shall be adopted unless its introduction produces a positive net benefit; b) all exposures shall be kept as low as reasonably achievable, economic and social factors being taken into account; and C) the dose equivalent to individuals shall not exceed the limits recommended for the appropriate circumstances by the Commission. The levels for basic dose

Antenna modeling considerations for accurate SAR calculations in human phantoms in close proximity to GSM cellular base station antennas.

Science.gov (United States)

van Wyk, Marnus J; Bingle, Marianne; Meyer, Frans J C

2005-09-01

International bodies such as International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute for Electrical and Electronic Engineering (IEEE) make provision for human exposure assessment based on SAR calculations (or measurements) and basic restrictions. In the case of base station exposure this is mostly applicable to occupational exposure scenarios in the very near field of these antennas where the conservative reference level criteria could be unnecessarily restrictive. This study presents a variety of critical aspects that need to be considered when calculating SAR in a human body close to a mobile phone base station antenna. A hybrid FEM/MoM technique is proposed as a suitable numerical method to obtain accurate results. The verification of the FEM/MoM implementation has been presented in a previous publication; the focus of this study is an investigation into the detail that must be included in a numerical model of the antenna, to accurately represent the real-world scenario. This is accomplished by comparing numerical results to measurements for a generic GSM base station antenna and appropriate, representative canonical and human phantoms. The results show that it is critical to take the disturbance effect of the human phantom (a large conductive body) on the base station antenna into account when the antenna-phantom spacing is less than 300 mm. For these small spacings, the antenna structure must be modeled in detail. The conclusion is that it is feasible to calculate, using the proposed techniques and methodology, accurate occupational compliance zones around base station antennas based on a SAR profile and basic restriction guidelines. (c) 2005 Wiley-Liss, Inc.

The mandate and work of ICRP Committee 3 on radiological protection in medicine.

Science.gov (United States)

Miller, D L; Martin, C J; Rehani, M M

2018-01-01

The mandate of Committee 3 of the International Commission on Radiological Protection (ICRP) is concerned with the protection of persons and unborn children when ionising radiation is used in medical diagnosis, therapy, and biomedical research. Protection in veterinary medicine has been newly added to the mandate. Committee 3 develops recommendations and guidance in these areas. The most recent documents published by ICRP that relate to radiological protection in medicine are 'Radiological protection in cone beam computed tomography' (ICRP Publication 129) and 'Radiological protection in ion beam radiotherapy' (ICRP Publication 127). A report in cooperation with ICRP Committee 2 entitled 'Radiation dose to patients from radiopharmaceuticals: a compendium of current information related to frequently used substances' (ICRP Publication 128) has also been published. 'Diagnostic reference levels in medical imaging' (ICRP Publication 135), published in 2017, provides specific advice on the setting and use of diagnostic reference levels for diagnostic and interventional radiology, digital imaging, computed tomography, nuclear medicine, paediatrics, and multi-modality procedures. 'Occupational radiological protection in interventional procedures' was published in March 2018 as ICRP Publication 139. A document on radiological protection in therapy with radiopharmaceuticals is likely to be published in 2018. Work is in progress on several other topics, including appropriate use of effective dose in collaboration with the other ICRP committees, guidance for occupational radiological protection in brachytherapy, justification in medical imaging, and radiation doses to patients from radiopharmaceuticals (an update to ICRP Publication 128). Committee 3 is also considering the development of guidance on radiological protection in medicine related to individual radiosusceptibility, in collaboration with ICRP Committee 1.

Environmental radiation protection. The new ICRP concept

International Nuclear Information System (INIS)

Kaps, C.; Lorenz, B.

2013-01-01

Protection of the environment regarding radiation protection was so far reduced to the concept: if man is protected the environment is protected well enough. This was derived from the radiosensitivity curve, according to which highly developed organisms are more sensible to radiation than less highly developed. ICRP publication 103 put this simple concept in question. Even before, ICRP set up a committee to discuss this theme. End of 2012 ICRP released a new concept of environmental protection regarding different exposure situations and brought it up for discussion in the internet. This concept is based on Reference Animals and Plants (RAPs) and analogous to the concept of the protection for man. The exposure for representative organisms regarding ionizing radiation shall be estimated and compared with Derived Consideration Reference Levels (DCRLs). If the DCRLs are reached or exceeded there is a need to react. This concept raises several questions. (orig.)

What we expect of ICRP new recommendations

International Nuclear Information System (INIS)

Yoshikawa, S.

2004-01-01

We believe that it is essential for Japan to continue to maintain and promote nuclear power generation. To promote nuclear power generation, we believe it is important that the effect of low-level radiation on humans and the exposure dose limits have to be widely and properly understood by the general public and radiation workers. From such a point of view, we express our agreement with ICRP latest attempt that is aimed at preparing a simple and easy-to understanding radiological protection system. We would like to express some of our opinions about ICRP new recommendations. - The relation between PAL and the conventional dose limit should be shown clearly. - Optimisation on low-enough level (natural background level) should be omitted. - The process of optimisation must take the state of affairs in each country into consideration. - The dose limits (100 mSv/5 yrs and 50 mSv/yr) for workers should not be changed. (Single-year dose limit of 20 mSv/yr has no flexibility and has serious impact on nuclear power operators.). - Full discussion is necessary to establish the radiological protection criteria for environment. We appreciate ICRP's releases and calls for opinions regarding the new recommendations. We hope ICRP continues to disclose the status of discussion in a timely manner, and invite opinions. (author)

Structural Modeling and Analysis on Dynamic Characteristics of Antenna Pedestal in Airborne SAR

Directory of Open Access Journals (Sweden)

He Li-ping

2012-06-01

Full Text Available Finite element modeling and structural dynamic characteristics of antenna pedestal in airborne SAR were studied in this paper. The Finite element model of antenna pedestal in airborne SAR was set up on the basis of structural dynamic theory, then, the key technologies of dynamic simulation were pointed out, and the modal analysis and transient analysis were carried out. Simulation results show that the dynamic characteristics of antenna pedestal in airborne SAR can meet the requirements of servo bandwidth and structural strength. The fast finite element modeling and simulation method proposed in this paper are of great significance to the weight reducing design of antenna pedestal in airborne SAR.

Development of polygonal surface version of ICRP reference phantoms: Preliminary study for posture change

International Nuclear Information System (INIS)

Nguyen, Tat Thang; Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong

2013-01-01

Even though International Commission on Radiological Protection (ICRP) officially adopted a set of adult male and female voxel phantoms as the ICRP reference phantoms, there are several critical limitations due to the nature of voxel geometry and their low voxel resolutions. In order to overcome these limitations of the ICRP phantoms, we are currently developing polygonal surface version of ICRP reference phantoms by directly converting the ICRP voxel phantoms to polygonal surface geometries. Among the many advantages of the ICRP polygonal surface phantom, especially, it is flexible and deformable. In principle, it is, therefore, possible to make the posture-changed ICRP phantoms which can provide more accurate dose values for exposure situations strongly relevant to worker's postures. As a preliminary study for developing the posture-changed ICRP phantoms, in this work we changed the posture of the preliminary version of ICRP male polygon-surface phantom constructed in the previous study. Organ doses were then compared between original and posture-changed phantoms. In the present study, we successfully changed a posture of the preliminary version of ICRP male polygon-surface phantom to the walking posture. From this results, it was explicitly shown that the polygon-surface version of the ICRP phantoms can be sufficiently modified to be various postures with the posture-changing method used in this study. In addition, it was demonstrated that phantom's posture must be considered in certain exposure situations, which can differ dose values from the conventional standing-posture phantom

Critique of the use of ICRP-29's 'Robustness Index' in evaluating uncertainties associated with radiological assessment models

Energy Technology Data Exchange (ETDEWEB)

Hoffman, F O; Schwarz, G; Killough, G G [Oak Ridge National Lab., TN (USA)

1980-08-01

Concern is expressed regarding the use of the robustness index, as proposed in ICRP 29, to characterise the uncertainties associated with a model's predictions. Results of a Monte Carlo simulation employing a model of the grass-cow-milk-infant pathway for /sup 131/I are used to elucidate the author's criticisms. It is recommended that the robustness index should be carefully examined to appraise its possible usefulness and potential dangers. Alternate methods for analysis of uncertainty are proposed.

Accumulation of plutonium in mammalian wildlife tissues: comparison of recent data with the ICRP distribution models

Energy Technology Data Exchange (ETDEWEB)

Johansen, M.; Child, D.; Davis, E.; Hotchkis, M.; Payne, T. [Australian Nuclear Science and Technology Org. (Australia); Ikeda-Ohno, A. [University of New South Wales (Australia); Twining, J. [Austral Radioecology (Australia)

2014-07-01

concentrations in O. cuniculus edible samples prepared according to traditional aboriginal methods were more than two orders of magnitude higher than in muscle alone. The increase was due to inclusion of GI tract components and contents in the traditional method. Our results provide new insights into the sequestration of Pu in mammalian tissues under environmental exposure conditions. These results contrast with those related to the specific forms of Pu and exposure conditions upon which the ICRP models were based. However, they provide data relevant to the assessment of key environmental legacy waste sites, and of potential release scenarios for the low-soluble oxide forms in the growing worldwide inventory of Pu associated with power production. Document available in abstract form only. (authors)

Radiation Protection for Radon in Dwellings - Consequences of the ICRP Publication 115

International Nuclear Information System (INIS)

Azzam, Jai T.; Breckow, J.; Grimm, V.; Grund, A.

2013-01-01

In the last decade several epidemiological studies on risk estimations due to exposure to radon in dwellings revealed higher risks to radon exposure than estimated previously. Thus, in ICRP Publication 115 (ICRP, 2011) a revised nominal probability coefficient for radon and its progeny-induced lung cancer was propounded. Based on the results of the exposure from residential studies and underground miners, the risk of lung cancer was estimated as 5x10 -4 per WLM (lifetime excess absolute risk, LEAR) and 8x10 -1 0 per Bqxh/m 3 , respectively. In the former Publication 65 (ICRP, 1993), the coefficient has been 2.83x10 -4 per WLM and 4x10 -1 0 per Bqxh/m 3 , respectively. Typical radon activity concentration in dwellings is about 60 Bq/m? in many parts of Europe. According to the ICRP Publication 65-dose coefficients, this concentration leads to a mean annual effective dose of 1.2 mSv. If the new nominal risk coefficient from ICRP Publication 115 is applied, the effective dose due to radon in dwellings increases to approximately 2.3 mSv per year. Referring the reference level of 10 mSv/a for radon exposure in dwellings in ICRP Publication 103 (ICRP, 2007) and based on the new recommendations in ICRP Publication 115, actions have to be taken to reduce the upper reference level for radon gas in dwellings from 600 Bq/m 3 to 300 Bq/m 3 .(author)

A perspective on the ICRP approach to Radiation protection of the environment

International Nuclear Information System (INIS)

Mossman, K.L.

2003-01-01

The ICRP, in response to concerns by the environmental community, has begun the process of addressing radiation protection of non-human species. Concerns have been raised that the current framework for radiation protection fails to adequately protect the environment. Although most everyone agrees that some change to the ICRP radiation protection framework is called for, the extent of the revision is debatable. In May 2000, the ICRP set up a Task Group to provide advice on the development of a policy for the protection of the environment and to suggest a framework for environmental protection based on scientific, ethical, and philosophical principles. Based on Task Group input, ICRP intends to develop a framework for protection of the environment that can be integrated into an overall system of protection. This paper explores four major issues that serve to identify questions that ICRP should consider in its 2005 recommendations regarding radiation protection of the environment: (1) the role of ICRP, (2) defining the environment and criteria for protection, (3) the framework for environmental protection, and (4) risk management. (author)

Status of ICRP recommendations at nuclear power plants

International Nuclear Information System (INIS)

Kaneko, Masahito

1996-01-01

Results of actual radiation exposure in nuclear power plants and related matters were presented for discussion of the principle of radiation protection involved in ICRP recommendations, which is prerequisite for safe operation of the plants and for treatment of radioactive waste. There were no personnel with actual exposure dose exceeding 50 mSv/y in 1995. Total exposure dose was 66.32 psn.Sv. and mean dose equivalent/personnel, 1.0 mSv. The amount of radioactive gasses and liquids released in the environment was far lower (<1/7,000) than that for the exposure index of 50 microSv/y in the public around the plant. The marked decrease in the amount of radioactive solid waste was noted in the plants. The laws and ICRP recommendations have been the basis for agreement between labor and management in the plant: e.g., the proposed voluntary dose was 30 mSv/y. This was also true for the recommendations in 1990. Finally, followings were proposed to ICRP: re-examination of linear theory without threshold, consideration for the balance between the radiation and other kind of hazardous materials and factors, carefulness in changing the recommendation concept, and exclusion of more severe limitations than those included in ICRP recommendations. (K.H.)

New electrodynamic and electrostatic models with applications to antenna theory, superconductor slots, and lasers

International Nuclear Information System (INIS)

Eggleston, S.W.

1988-01-01

The common set of functions used as a basis for the solution to Helmholtz and Laplace's equations is expanded to include solutions not found in the handbooks. With this complete set of basis functions of integer indexes, a multicentered model is developed using Debye-like potentials for electrodynamics and standard potentials for electrostatics. The resonant modes of the model are the exact solution to a wide variety of thin linear antennas and antenna-like structures, narrow linear gaps in superconductors, microscopic linear lasers, and arbitrary linear charge distributions. The model is applied to a linear antenna of large-diameter, via Pocklington's and Hallen's integral equation. The nonsinusoidal current of this linear antenna of large-diameter is decomposed into idealized components using equal and unequal spacing, and single and many centered linear antennas. Babinet's principal is brought into play to apply the model to gaps in superconductors. The model of a laser is in the microscopic domain, a domain that has not been looked at previously. The electrostatic model allows the modeling of an arbitrary linear charge distribution between two points

User's manual to the ICRP Code: a series of computer programs to perform dosimetric calculations for the ICRP Committee 2 report

International Nuclear Information System (INIS)

Watson, S.B.; Ford, M.R.

1980-02-01

A computer code has been developed that implements the recommendations of ICRP Committee 2 for computing limits for occupational exposure of radionuclides. The purpose of this report is to describe the various modules of the computer code and to present a description of the methods and criteria used to compute the tables published in the Committee 2 report. The computer code contains three modules of which: (1) one computes specific effective energy; (2) one calculates cumulated activity; and (3) one computes dose and the series of ICRP tables. The description of the first two modules emphasizes the new ICRP Committee 2 recommendations in computing specific effective energy and cumulated activity. For the third module, the complex criteria are discussed for calculating the tables of committed dose equivalent, weighted committed dose equivalents, annual limit of intake, and derived air concentration

Radiological protection: a summary handbook of ICRP publications and recommendations

International Nuclear Information System (INIS)

Nagaratnam, A.

1995-01-01

The biological effects of radiation and potential risks therefrom far exceeds the knowledge of any other hazardous agent, whether in the industrial field, or in the general environment affecting members of the public. The International Commission on Radiological Protection (ICRP) has been playing a pioneering role for decades in this direction. The extensive database that has been established over the decades by the ICRP, the methodologies, techniques and the organizational structures that have been developed to control radiation hazards, and, above all, the philosophy of risk evaluation and management that has been evolved by ICRP, would serve as valuable guides not only to those concerned with radiological protection but to scientist, technologist and administrators involved in all facets of occupational and industrial safety, as well as those concerned with environmental protection. From 1959 to the end of 1993 ICRP has brought out 64 publications running to around 9000 pages. It is important that everyone connected with the uses of ionizing radiations should be familiar with at least the basic features of the thinking of ICRP as embodied in these publications. The present handbook attempts to give in a concise, consolidated and codified form the salient features of all the relevant information contained in the voluminous ICRP publications. The material has been presented in 7 parts, each dealing with one major aspect of the recommendations, and summarizing the various publications connected with it. A separate note following the preface gives a brief summary of the way the contents of the handbook have been arranged. refs., tabs., figs

Modeling and control of antennas and telescopes

CERN Document Server

Gawronski, Wodek

2008-01-01

The book shows, step-by-step, the design, implementation, and testing of the antenna/telescope control system, from the design stage (analytical model) to fine tuning of the RF beam pointing (monopulse and conscan). It includes wide use of Matlab and Simulink..

Calculation of skin dose due to beta contamination using the new quantity of the ICRP 116: the local skin dose

International Nuclear Information System (INIS)

Bourgois, L.; Menard, S.; Comte, N.

2017-01-01

Values of the new protection quantity Local Skin Dose 'LSD', introduced by the International Commission on Radiological Protection (ICRP) Publication 116, were calculated for 134 β - or β + emitting radionuclides, using the Monte Carlo code MCNP6. Two types of source geometry are considered: a point source and disc-type surface contamination (the source is placed in contact with the skin). This new protection quantity is compared with the operational quantity H2 (0.07, 0 deg.), leading us to conclude that, in accordance with the rules of the ICRP, the operational quantity over-estimates the protection quantity to a reasonable extent, except in very rare cases for very low average beta energies. Thus, with the new skin model described in ICRP 116, there are no longer any major differences between the operational quantities and protection quantities estimated with the skin model described in ICRP 74. (authors)

A Method of Auxiliary Sources Approach for Modelling the Impact of Ground Planes on Antenna

DEFF Research Database (Denmark)

Larsen, Niels Vesterdal; Breinbjerg, Olav

2006-01-01

The Method of Auxiliary Sources (MAS) is employed to model the impact of finite ground planes on the radiation from antennas. Two different antenna test cases are shown and the calculated results agree well with reference measurements......The Method of Auxiliary Sources (MAS) is employed to model the impact of finite ground planes on the radiation from antennas. Two different antenna test cases are shown and the calculated results agree well with reference measurements...

ICRP (1991) and deterministic effects

International Nuclear Information System (INIS)

Mole, R.H.

1992-01-01

A critical review of ICRP Publication 60 (1991) shows that considerable revisions are needed in both language and thinking about deterministic effects (DE). ICRP (1991) makes a welcome and clear distinction between change, caused by irradiation; damage, some degree of deleterious change, for example to cells, but not necessarily deleterious to the exposed individual; harm, clinically observable deleterious effects expressed in individuals or their descendants; and detriment, a complex concept combining the probability, severity and time of expression of harm (para42). (All added emphases come from the author.) Unfortunately these distinctions are not carried through into the discussion of deterministic effects (DE) and two important terms are left undefined. Presumably effect may refer to change, damage, harm or detriment, according to context. Clinically observable is also undefined although its meaning is crucial to any consideration of DE since DE are defined as causing observable harm (para 20). (Author)

ICRP proposal on radiation protection of non-human species - with TAEA perspective-

International Nuclear Information System (INIS)

Okyar, H. B.

2006-01-01

Interest in the protection of the environment has greatly increased in recent years, in relation to all aspects of human activities. Such interest has been accompanied by the development and application of various means of assessing and managing the many forms of human impact upon it. Up to now, the International Commission on Radiation Protection (ICRP) has not published any recommendations on how to assess or manage radiation effects in non-human species. The Turkish Atomic Energy Authority (TAEA) which is the regulatory body of Turkey in radiation protection also recognises that there is a current lack of consistency at international level with respect to addressing such issues in relation to radioactivity, and therefore believes that a more proactive approach is now necessary. The Commission has decided to develop a framework for the assessment of radiation effects in non-human species in order to fill a conceptual gap in radiation protection. The proposed system does not intend to set regulatory standards, but rather to provide guidance and help regulators and operators demonstrate compliance with existing legislation. ICRP developed a small set of reference animals and plants, plus their relevant data bases to serve as a basis for the more fundamental understanding and interpretation of the relationships between exposure and dose, and between dose and certain categories of effect. This concept is similar to that of the reference individual (reference man) used for human radiological protection, in that it is intended to act as a basis for calculations and decisions. The Commission has now established a system to continue the work with defining effects end-points of interest, the types of reference organisms to be used by ICRP, and defining a set of reference dose models for assessing and managing radiation exposure in non-human species. This talk will provide a review of ICRP proposed framework for radiation protection of the environment with TAEA comments

What do we know? where do we go from here? implications for ICRP developments

International Nuclear Information System (INIS)

Clarke, R.

2002-01-01

This first Nea forum is ' in collaboration with ICRP' and we wanted views from participants regarding our initiative on radiological protection of the environment. The members of the main Commission of ICRP who have attended this forum have been delighted with the outcome. ICRP has a range of options for its future activity with regard to radiological protection of the environment, starting with withdrawing altogether from the subject, through maintaining our current assertion, to fully developing a new policy. The emerging consensus from this meeting would suggest that the key elements of a system would involve a clear set of objectives and principles, an agreed set of quantities and units, a reference set of dose models for a defined number of reference fauna and flora, basic knowledge of radiation effects, a means of demonstrating compliance, regular views and revisions as new knowledge develops. (N.C.)

ICRP putting wealth before health

International Nuclear Information System (INIS)

Green, P.

1990-01-01

Reductions in recommended dose limits for radiation workers set by the International Commission for Radiological Protection do not go far enough. The ICRP has put industry profitability before worker safety, and their recommendations should not be the basis for UK or European law. (author)

ICRP 60 - the next step

International Nuclear Information System (INIS)

Harding, L.K.; Thomson, W.H.

1993-01-01

Following the publication in 1990 of the recommendations proposed by the International Commission on Radiological protection (ICRP 60), this editorial briefly highlights the advice given by the NRPB to UK government departments on how to implement those recommendations regarding occupational, medical and public exposure. (UK)

Optimization of wearable microwave antenna with simplified electromagnetic model of the human body

Science.gov (United States)

Januszkiewicz, Łukasz; Barba, Paolo Di; Hausman, Sławomir

2017-12-01

In this paper the problem of optimization design of a microwave wearable antenna is investigated. Reference is made to a specific antenna design that is a wideband Vee antenna the geometry of which is characterized by 6 parameters. These parameters were automatically adjusted with an evolution strategy based algorithm EStra to obtain the impedance matching of the antenna located in the proximity of the human body. The antenna was designed to operate in the ISM (industrial, scientific, medical) band which covers the frequency range of 2.4 GHz up to 2.5 GHz. The optimization procedure used the finite-difference time-domain method based full-wave simulator with a simplified human body model. In the optimization procedure small movements of antenna towards or away of the human body that are likely to happen during real use were considered. The stability of the antenna parameters irrespective of the movements of the user's body is an important factor in wearable antenna design. The optimization procedure allowed obtaining good impedance matching for a given range of antenna distances with respect to the human body.

Basic concepts and assumptions behind the new ICRP recommendations

International Nuclear Information System (INIS)

Lindell, B.

1979-01-01

A review is given of some of the basic concepts and assumptions behind the current recommendations by the International Commission on Radiological Protection in ICRP Publications 26 and 28, which form the basis for the revision of the Basic Safety Standards jointly undertaken by IAEA, ILO, NEA and WHO. Special attention is given to the assumption of a linear, non-threshold dose-response relationship for stochastic radiation effects such as cancer and hereditary harm. The three basic principles of protection are discussed: justification of practice, optimization of protection and individual risk limitation. In the new ICRP recommendations particular emphasis is given to the principle of keeping all radiation doses as low as is reasonably achievable. A consequence of this is that the ICRP dose limits are now given as boundary conditions for the justification and optimization procedures rather than as values that should be used for purposes of planning and design. The fractional increase in total risk at various ages after continuous exposure near the dose limits is given as an illustration. The need for taking other sources, present and future, into account when applying the dose limits leads to the use of the commitment concept. This is briefly discussed as well as the new quantity, the effective dose equivalent, introduced by ICRP. (author)

Development and validation of a low-frequency modeling code for high-moment transmitter rod antennas

Science.gov (United States)

Jordan, Jared Williams; Sternberg, Ben K.; Dvorak, Steven L.

2009-12-01

The goal of this research is to develop and validate a low-frequency modeling code for high-moment transmitter rod antennas to aid in the design of future low-frequency TX antennas with high magnetic moments. To accomplish this goal, a quasi-static modeling algorithm was developed to simulate finite-length, permeable-core, rod antennas. This quasi-static analysis is applicable for low frequencies where eddy currents are negligible, and it can handle solid or hollow cores with winding insulation thickness between the antenna's windings and its core. The theory was programmed in Matlab, and the modeling code has the ability to predict the TX antenna's gain, maximum magnetic moment, saturation current, series inductance, and core series loss resistance, provided the user enters the corresponding complex permeability for the desired core magnetic flux density. In order to utilize the linear modeling code to model the effects of nonlinear core materials, it is necessary to use the correct complex permeability for a specific core magnetic flux density. In order to test the modeling code, we demonstrated that it can accurately predict changes in the electrical parameters associated with variations in the rod length and the core thickness for antennas made out of low carbon steel wire. These tests demonstrate that the modeling code was successful in predicting the changes in the rod antenna characteristics under high-current nonlinear conditions due to changes in the physical dimensions of the rod provided that the flux density in the core was held constant in order to keep the complex permeability from changing.

ICRF antenna Faraday shield plasma sheath model

International Nuclear Information System (INIS)

Whealton, J.H.; Ryan, P.M.; Raridon, R.J.

1990-01-01

A two-dimensional nonlinear formulation that explicitly considers the plasma edge near a Faraday shield in a self-consistent manner is used in the modeling of the ion motion for a Faraday shield concept and model suggested by Perkins. Two models are considered that may provide significant insight into the generation of impurities for ion cyclotron resonance heating (ICRH) antennas. In one of these models a significant sheath periodically forms next to the Faraday screen, with ion acoustic waves heating the ions in the plasma. (orig.)

User's manual to the ICRP Code: a series of computer programs to perform dosimetric calculations for the ICRP Committee 2 report

Energy Technology Data Exchange (ETDEWEB)

Watson, S.B.; Ford, M.R.

1980-02-01

A computer code has been developed that implements the recommendations of ICRP Committee 2 for computing limits for occupational exposure of radionuclides. The purpose of this report is to describe the various modules of the computer code and to present a description of the methods and criteria used to compute the tables published in the Committee 2 report. The computer code contains three modules of which: (1) one computes specific effective energy; (2) one calculates cumulated activity; and (3) one computes dose and the series of ICRP tables. The description of the first two modules emphasizes the new ICRP Committee 2 recommendations in computing specific effective energy and cumulated activity. For the third module, the complex criteria are discussed for calculating the tables of committed dose equivalent, weighted committed dose equivalents, annual limit of intake, and derived air concentration.

ICRP Publication 84 of the ICRP. Pregnancy and medical irradiation; ICRP publication 84 de la CIPR. Grossesse et irradiation medicale

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

In this volume, the ICRP answers questions relative to medical irradiation of pregnant women, that without responses could lead to unappropriated behaviours. It gives the circumstances for a women to be irradiated, the radiation doses delivered by the radiological procedures for a diagnosis and for a therapy. The risks for the fetus and the woman are tackled, their part in the general risks of the pregnancy and the information to give to the future mother. (N.C.)

ZZ NUCDECAY, Nuclear Decay Data for Radiation Dosimetry Calculation for ICRP and MIRD

International Nuclear Information System (INIS)

Eckerman, K.F.; Westfall, R.J.; Ryman, J.C.; Cristy, M.

1995-01-01

1 - Description of program or function: - ICRP38: Format: Special format. Number of groups: Energies and intensities of radiations emitted; designed to address the needs in medical, environmental, and occupational radiation protection. Nuclides: 825 + 13 radionuclides. Origin: ENSDF (data used in preparing ICRP Publication 38). - MIRD: Format: Special format. Number of groups: Energies and intensities of radiations emitted; designed to address the needs in medical, environmental, and occupational radiation protection. Nuclides: 242 radionuclides. Origin: ENSDF (monograph of the MIRD Committee). The unabridged data used in preparing ICRP Publication 38 and a monograph of the MIRD Committee are distributed in electronic form in this package. The data are assembled in two collections. The collection referred to as ICRP38 consists of data on the energies and intensities of radiations emitted by the 825 radionuclides reported, although abridged, in ICRP Publication 38 plus an additional 13 radionuclides evaluated during preparation of a monograph for the MIRD Committee. The second collection, denoted as MIRD, contains data for the 242 radionuclides in the MIRD monograph noted above. Each collection consists of three ASCII files: (1) the index file (ICRP38.IDX or MIRD.IDX) is a sorted list of the radionuclides with pointers into the data files; (2) the radiation file (ICRP38.RAD or MIRD.RAD) contains data on the energies and intensities of the emitted radiations; (3) the beta spectra file (ICRP38.BET or MIRD.BET) contains the spectra for all beta emitters in the collection. 161 radionuclides of the MIRD collection have later ENSDF dates than those in the ICRP38 collection. In most instances, the differences are of no dosimetric significance, but considerable differences may exist for some nuclides. 2 - Method of solution: This data base has been designed to address the needs in medical, environmental, and occupational radiation protection. Calculations of the spatial

Significance of the new ICRP dose limits in the Indian context

International Nuclear Information System (INIS)

Mehta, S.K.

1993-01-01

The ICRP estimates the risk quantities using the primary risk coefficients from the results of Japanese survivor studies (with DDREF of 2) along with the all-causes mortality and survival probabilities of the Swedish population. In the present work, risk quantities have been computed using the ICRP estimates of the attributable conditional cancer death probability rates for different exposure levels along with the survival probabilities of the Indian population from the official Indian life tables. For this purpose the parameters of the latest Indian life tables are extrapolated beyond the highest tabulated age of 70 years by 'logit transformation' using the parameters of the complete Indian life table to age 100 years for the period 1951-60 as standard. The results of the present work show that the Indian and the Swedish-ICRP risk quantity estimates are consistent as a function of the life expectancies of the populations and that the Swedish-ICRP risk quantity estimates contain safety factors of about 2 in the Indian context. (author)

Plasmonic-cavity model for radiating nano-rod antennas

DEFF Research Database (Denmark)

Peng, Liang; Mortensen, N. Asger

2014-01-01

In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the ......In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition...... and the radiation efficiency. With our theoretical model, we show that besides the plasmonic resonances, efficient radiation takes advantage of (a) rendering a large value of the rods' radius and (b) a central-fed profile, through which the radiation efficiency can reach up to 70% and even higher in a wide...... frequency band. Our theoretical expressions and conclusions are general and pave the way for engineering and further optimization of optical antenna systems and their radiation patterns....

Overview of ICRP Committee 4: application of the Commission's recommendations.

Science.gov (United States)

Cool, D A

2016-06-01

Committee 4 develops principles and recommendations on radiological protection of people in all exposure situations. The committee meeting in 2014 was hosted by GE Healthcare in Arlington Heights, IL, USA on 27 July-1 August 2014. The programme of work of Committee 4 encompasses several broad areas, including a series of reports covering various aspects of existing exposure situations, leading the efforts of the International Commission on Radiological Protection (ICRP) to update and elaborate recommendations in light of the accident at Fukushima Daiichi nuclear power plant for emergencies and living in contaminated areas, elaborating the underpinnings of the system of radiological protection, and developing focussed reports on specific topic areas in consultation with ICRP's special liaison organisations. Committee 4 has six active Task Groups working on naturally occurring radioactive material; cosmic radiation in aviation; updates of ICRP Publications 109 and 111; ethics of radiological protection; surface and near-surface disposal of solid radioactive waste; and exposures resulting from contaminated sites from past industrial, military, and nuclear activities. In addition, there is a Working Party on tolerability of risk, and ongoing work with the various special liaison organisations of ICRP. © The International Society for Prosthetics and Orthotics.

Efficiency factors for Phoswich based lung monitor using ICRP Voxel phantoms

International Nuclear Information System (INIS)

Manohari, M.; Mathiyarasu, R.; Rajagopal, V.; Jose, M.T.; Venkatraman, B.

2016-01-01

The actinide contamination in lungs is measured either using array of HPGe detector or Phoswich based lung monitors. This paper discusses the results obtained during numerical calibration of Phoswich based lung counting system using ICRP VOXEL phantoms. The results are also compared with measured efficiency values obtained using LLNL phantom. The efficiency factors of 241 Am present in the lungs for phoswich detector was simulated using ICRP male voxel phantom and compared with experimentally observed values using LLNL Phantom. The observed deviation is 12%. The efficiency of the same for female subjects was estimated using ICRP female voxel phantom for both supine and posterior geometries

Studies of heating efficiencies and models of RF-sheaths for the JET antennae

International Nuclear Information System (INIS)

Hedin, J.

1996-02-01

A theoretical model for the appearance of RF-sheaths is developed to see if this can explain the expected lower heating efficiencies of the new A 2 antennae at JET. The equations are solved numerically. A general method for evaluation of the experimental data of the heating efficiencies of the new antennae at JET is developed and applied for discharges with and without the bumpy limiter on the D antennae. 8 refs, 26 figs

ICRP-Radiation protection principles and practice

International Nuclear Information System (INIS)

Fry, R.M.

1982-01-01

A brief survey is given of the history of ICRP, its basic standards and recommendations and their rationale, from its foundation in 1928 to the latest major review of its recommendation in 1977. In this time the basic radiation standard for whole body irradiation of a radiation worker has dropped from the equivalent of 50 r per year (in 1934) through 15 rem per year (1954) to 5 rem per year in 1958. ICRP recommendations include maximum permissible doses for particular organs and a comprehensive list of derived limits governing the intake of radionuclides into the body, and dose limits for members of the public. Emphasis in current radiation protection practice is on avoiding all unnecessary exposures and keeping doses as far below dose limits as is reasonably achievable. The use of cost-benefit analysis to optimize protection and some of its inherent difficulties, is discussed

Practical and Simple Wireless Channel Models for Use in Multipolarized Antenna Systems

Directory of Open Access Journals (Sweden)

KwangHyun Jeon

2014-01-01

Full Text Available The next-generation wireless systems are expected to support data rates of more than 100 Mbps in outdoor environments. In order to support such large payloads, a polarized antenna may be employed as one of the candidate technologies. Recently, the third generation partnership standards bodies (3GPP/3GPP2 have defined a cross-polarized channel model in SCM-E for MIMO systems; however, this model is quite complex since it considers a great many channel-related parameters. Furthermore, the SCM-E channel model combines the channel coefficients of all the polarization links into one complex output, making it impossible to exploit the MIMO spatial multiplexing or diversity gains in the case of employing polarized antenna at transmitter and receiver side. In this paper, we present practical and simple 2D and 3D multipolarized multipath channel models, which take into account both the cross-polarization discrimination (XPD and the Rician factor. After verifying the proposed channel models, the BER and PER performances and throughput using the EGC and MRC combining techniques are evaluated in multipolarized antenna systems.

Implications of draft ICRP recommendations: the View of the OECD Nuclear Energy Agency

International Nuclear Information System (INIS)

Magnusson, S.; Lazo, T.

2006-01-01

Full text: The OECD Nuclear Energy Agency has taken an active interest in the work being performed by the International Commission on Radiological Protection (ICRP) to develop a new set of general recommendations. As several key junctures, the Nea, through the lead of its Committee on Radiation Protection and Public Health (C.R.P.P.H.) has performed in-depth analyses of the possible implications that draft ICRP materials, in order to inform policy makers of the regulatory and application implications that would result should draft ICRP Recommendations for a system of radiological protection be published. Comments from the Nea have constructively contributed to the ICRP development process, and it is hoped that the final ICRP recommendations in this area will be developed to best serve the needs of national and international radiation protection policy makers, regulators and implementers. Having assessed and commented on previous drafts, the C.R.P.P.H. has co-ordinated the views of all the relevant standing technical committees within the OECD Nuclear Energy Agency to provide constructive suggestions as to how the text could be usefully improved. Comments were requested from the Nea committees dealing with radioactive waste management, nuclear safety, nuclear regulatory activities, nuclear development and nuclear science. The present paper summarises the results of the C.R.P.P.H. review process related to the new ICRP recommendations. (author)

Comparison of ICRP Publication 30 lung model-based predictions with measured bioassay data for airborne natural UO2 exposure

International Nuclear Information System (INIS)

Thind, K.S.

1987-01-01

In this paper a comparison is made between the build-up of U thorax burdens and the predicted total lung (lung and lymph) burden, based on the lung model provided in ICRP Publication 30 for a group of 29 atomic radiation workers at a Canadian fuel fabrication facility. A similar comparison is made between the predicted ratio of the total lung burden to urinary excretion and the ratio obtained from bioassay data. The study period for the comparison is 5 y. The inhalation input for the lung model calculations was derived from air-sampling data and the choice of particle size activity median aerodynamic diameter (AMAD) was guided by particle size measurements made at representative work locations. The pulmonary clearance half-times studied were 100, 250 and 500 d. For the purpose of this comparison, averaged exposure and averaged bioassay data for the group were used. This comparison indicates that for the conditions of this facility, the assumption of a 500-d pulmonary clearance half-time and a particle size of 1 micron (AMAD) may be too conservative. It is suggested that measurements of air concentrations and particle size used as input parameters for the ICRP Publication 30 lung model may be used to calculate bioassay parameters which may then be tested against bioassay data obtained as part of an operational health physics program, thereby giving a useful step towards defining a derived air concentration value for U in the workplace

Comments on ICRP-60 rationale for dose limits for the pregnant worker

International Nuclear Information System (INIS)

Myers, D.K.

1992-06-01

ICRP Publication 60 has recently recommended new dose limits for the radiation exposure of pregnant workers. These new dose limits for pregnant workers are more restrictive than the current limits in force in Canada. Recent presentations by Dr. R.H. Mole have faulted the arguments provided by ICRP as justification for reducing the previously recommended limits for pregnant radiation workers. The present paper provides a brief review of the development of the human conceptus, of the biological effects of low doses of radiation on the foetus, and discusses R.H. Mole's comments on ICRP-60. On the critical issues concerning the presence or absence of threshold doses for induction of specific biological endpoints, Dr. Mole and ICRP-60 appear to be in agreement. The basic disagreement between Dr. Mole and ICRP-60 seems to revolve around the philosophical question of whether dose limits should be based on quantitative risks to the foetus or whether dose limits to the pregnant worker should provide a standard of protection to the foetus which is broadly comparable with that provided for members of the general public. Further research is recommended on one of the topics raised by Dr. Mole, namely, foetal doses from radionuclides inhaled or ingested by the mother

The evolution of thoughts from ICRP 46 concept of potential exposure

International Nuclear Information System (INIS)

Sugier, A.

2008-01-01

Since issuing its latest basic recommendations in 1991 as ICRP Publication 60, the Commission has reviewed these recommendations regularly and, from time to time, has issued supplementary reports in the Annals of the ICRP. The extent of these supplementary reports has indicated a need for consolidation and rationalization. New scientific data have also been published since Publication 60, and while the biological and physical assumptions and concepts remain robust, some updating is required. In addition, there have been societal developments in that more emphasis is now given on the protection of individuals and stakeholder involvement in the management of radiological risk. Finally, it has also become apparent that the radiological protection of non-human species should receive more emphasis than in the past. It is against this background that the Commission has now decided to adopt a revised set of Recommendations while at the same time maintaining stability with the previous recommendations. Following several years of an open and worldwide discussion process, mainly through web consultation, ICRP intends to publish its new recommendations in 2007. In the context of AEN/NEA seminar on safety case for the deep disposal of radioactive waste, it appeared necessary first of all to examine the above mentioned evolution of ICRP system, as well as to recall the main ICRP publications on potential exposure and waste disposal and finally to focus on the main recommendations on solid waste disposal which are still valid. (author)

A constructive critique to the ICRP's system and counter proposal

International Nuclear Information System (INIS)

Katoh, K.

1998-01-01

In the author's opinion, there is a need for continuous efforts in revising the systems of radiation protection designed and operated according to ICRP recommendations. The fundamentals of the ICRP system of radiation protection are analyzed and classified into scientific and political or strategic features. Several proposals for changes are presented, concerning the restoration of the causality relation for radiation protection, the criteria for safety controlling, and the methodology of exposure control. (A.K.)

On Connectivity of Wireless Sensor Networks with Directional Antennas

Directory of Open Access Journals (Sweden)

Qiu Wang

2017-01-01

Full Text Available In this paper, we investigate the network connectivity of wireless sensor networks with directional antennas. In particular, we establish a general framework to analyze the network connectivity while considering various antenna models and the channel randomness. Since existing directional antenna models have their pros and cons in the accuracy of reflecting realistic antennas and the computational complexity, we propose a new analytical directional antenna model called the iris model to balance the accuracy against the complexity. We conduct extensive simulations to evaluate the analytical framework. Our results show that our proposed analytical model on the network connectivity is accurate, and our iris antenna model can provide a better approximation to realistic directional antennas than other existing antenna models.

ICRP-recommendations on dose limits for workers

International Nuclear Information System (INIS)

Beninson, D.J.

1976-01-01

Dose limits proposed by the ICRP have been incorporated in most national and international standards and their respect has caused a distribution of doses with a average not exceeding 1/10 of the maximum permissible dose. This distribution corresponds to a risk which is well within the risks in 'safe industries'. There are at present some inconsistancies in the current system of recommended limits, for example having the same limit of 5 rem for the whole-body and also for some organs. Hopefully, this incosistancy will be removed in the next recommendation of the ICRP. But the whole-body limit of 5 rem in a year has been safe and there is little ground to reduce this limit on the basis of comparisons with 'safe industries'. (orig./HP) [de

ICRP 2015. International symposium on the radiation protection system. Report and reflection on a significant symposium; ICRP 2015. 3. Internationales Symposium zum System des Strahlenschutzes. Bericht und Reflexion ueber ein bedeutsames Symposium

Energy Technology Data Exchange (ETDEWEB)

Lorenz, Bernd

2016-08-01

The ICRP international symposium on the radiation protection system provides always extensive information on new developments in radiation protection. The ICRP 2105 discussed the following issues: radiation effects of low dose irradiation, dose coefficients for internal and external exposures, radiation protection in nuclear medicine, application of ICRP recommendations, environmental protection, studies on existing exposure situations, medical radiation protection today, science behind radiation doses, new developments in radiation effects, and ethics in radiation protection.

Survey of the ICRP 103 detriment-model

International Nuclear Information System (INIS)

Emami, S.; Buermeyer, J.; Spruck, K.; Breckow, J.

2016-01-01

The detriment of ICRP 103 is roughly defined as the product of the (organ specific) risk coefficient and the ''damage'' that may be associated with a (organ specific) cancer or hereditary effect, respectively. This is to indicate a weighted risk according to the radiation sensitivity of the different organs and the severity of damage that may possibly arise. Whereas the risk coefficients refer to radiation exposure parameters, the scale or degree of damage is independent of these parameters. The radiation independent parameters are the lethality, the loss of quality of life and the reduced life expectancy, which are considered as quantities associated with the severity of disease or damage, respectively. These parameters may change gradually, on the one hand possibly due to an increase of cancer becoming a common disease within the population. On the other hand, possibly to a decrease of cancer due to the progress in medical diagnostics and treatments that allow patients to survive or at least maintain a higher life quality standard. The damage and therefore the detriment appears to be mostly affected by the lethality. The lethality is the quotient of mortality to incidence. The investigation of the detriment presented in this paper focuses on the influence of the lethality on the detriment from 1980-2012 in Germany and USA.

Recent developments in ICRF antenna modelling

International Nuclear Information System (INIS)

Lamalle, P.U.; Messiaen, A.M.; Dumortier, P.; Louche, F.

2005-01-01

The antennas presently developed for ICRF heating of the ITER plasma consist of a tightly packed array of a large number of radiating straps, in order to deliver a high power density without exceeding radio-frequency voltage standoffs. Recently developed commercial software has enabled important progress in the coupling analysis and optimisation of such demanding systems. Approximations allowing to convincingly include a realistic plasma description in these codes are discussed. Application of the resulting numerical tools is illustrated by simulation of the existing JET A2 ICRF array, with the goal to validate simulations for future antennas. Advances in the design of realistic test bed conditions, using salted water as a means of creating plasma-relevant antenna loading, and the appropriate scaling of a mockup are also presented. (author)

Magnetic antenna excitation of whistler modes. IV. Receiving antennas and reciprocity

Energy Technology Data Exchange (ETDEWEB)

Stenzel, R. L., E-mail: stenzel@physics.ucla.edu; Urrutia, J. M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

2015-07-15

Antenna radiation patterns are an important property of antennas. Reciprocity holds in free space and the radiation patterns for exciting and receiving antennas are the same. In anisotropic plasmas, radiation patterns are complicated by the fact that group and phase velocities differ and certain wave properties like helicity depend on the direction of wave propagation with respect to the background magnetic field B{sub 0}. Interference and wave focusing effects are different than in free space. Reciprocity does not necessarily hold in a magnetized plasma. The present work considers the properties of various magnetic antennas used for receiving whistler modes. It is based on experimental data from exciting low frequency whistler modes in a large uniform laboratory plasma. By superposition of linear waves from different antennas, the radiation patterns of antenna arrays are derived. Plane waves are generated and used to determine receiving radiation patterns of different receiving antennas. Antenna arrays have radiation patterns with narrow lobes, whose angular position can be varied by physical rotation or electronic phase shifting. Reciprocity applies to broadside antenna arrays but not to end fire arrays which can have asymmetric lobes with respect to B{sub 0}. The effect of a relative motion between an antenna and the plasma has been modeled by the propagation of a short wave packet moving along a linear antenna array. An antenna moving across B{sub 0} has a radiation pattern characterized by an oscillatory “whistler wing.” A receiving antenna in motion can detect any plane wave within the group velocity resonance cone. The radiation pattern also depends on loop size relative to the wavelength. Motional effects prevent reciprocity. The concept of the radiation pattern loses its significance for wave packets since the received signal does not only depend on the antenna but also on the properties of the wave packet. The present results are of fundamental

Magnetic antenna excitation of whistler modes. IV. Receiving antennas and reciprocity

International Nuclear Information System (INIS)

Stenzel, R. L.; Urrutia, J. M.

2015-01-01

Antenna radiation patterns are an important property of antennas. Reciprocity holds in free space and the radiation patterns for exciting and receiving antennas are the same. In anisotropic plasmas, radiation patterns are complicated by the fact that group and phase velocities differ and certain wave properties like helicity depend on the direction of wave propagation with respect to the background magnetic field B 0 . Interference and wave focusing effects are different than in free space. Reciprocity does not necessarily hold in a magnetized plasma. The present work considers the properties of various magnetic antennas used for receiving whistler modes. It is based on experimental data from exciting low frequency whistler modes in a large uniform laboratory plasma. By superposition of linear waves from different antennas, the radiation patterns of antenna arrays are derived. Plane waves are generated and used to determine receiving radiation patterns of different receiving antennas. Antenna arrays have radiation patterns with narrow lobes, whose angular position can be varied by physical rotation or electronic phase shifting. Reciprocity applies to broadside antenna arrays but not to end fire arrays which can have asymmetric lobes with respect to B 0 . The effect of a relative motion between an antenna and the plasma has been modeled by the propagation of a short wave packet moving along a linear antenna array. An antenna moving across B 0 has a radiation pattern characterized by an oscillatory “whistler wing.” A receiving antenna in motion can detect any plane wave within the group velocity resonance cone. The radiation pattern also depends on loop size relative to the wavelength. Motional effects prevent reciprocity. The concept of the radiation pattern loses its significance for wave packets since the received signal does not only depend on the antenna but also on the properties of the wave packet. The present results are of fundamental interest and of

Microwave Ablation: Comparison of Simultaneous and Sequential Activation of Multiple Antennas in Liver Model Systems.

Science.gov (United States)

Harari, Colin M; Magagna, Michelle; Bedoya, Mariajose; Lee, Fred T; Lubner, Meghan G; Hinshaw, J Louis; Ziemlewicz, Timothy; Brace, Christopher L

2016-01-01

To compare microwave ablation zones created by using sequential or simultaneous power delivery in ex vivo and in vivo liver tissue. All procedures were approved by the institutional animal care and use committee. Microwave ablations were performed in both ex vivo and in vivo liver models with a 2.45-GHz system capable of powering up to three antennas simultaneously. Two- and three-antenna arrays were evaluated in each model. Sequential and simultaneous ablations were created by delivering power (50 W ex vivo, 65 W in vivo) for 5 minutes per antenna (10 and 15 minutes total ablation time for sequential ablations, 5 minutes for simultaneous ablations). Thirty-two ablations were performed in ex vivo bovine livers (eight per group) and 28 in the livers of eight swine in vivo (seven per group). Ablation zone size and circularity metrics were determined from ablations excised postmortem. Mixed effects modeling was used to evaluate the influence of power delivery, number of antennas, and tissue type. On average, ablations created by using the simultaneous power delivery technique were larger than those with the sequential technique (P Simultaneous ablations were also more circular than sequential ablations (P = .0001). Larger and more circular ablations were achieved with three antennas compared with two antennas (P simultaneous power delivery creates larger, more confluent ablations with greater temperatures than those created with sequential power delivery. © RSNA, 2015.

Comparison between Brazilian radiation protection norm and ICRP recommendations published in 2007

Energy Technology Data Exchange (ETDEWEB)

Pereira, Wagner de S.; Py Junior, Delcy de A., E-mail: pereiraws@gmail.com [Industrias Nucleares do Brasil (INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerio. Servico de Radioprotecao. Grupo Multidisciplinar de Radioprotecao; Pereira, Juliana R. de S., E-mail: pereirarsj@gmail.com [Universidade Federal de Alfenas, Pocos de Caldas, MG (Brazil). Campus Pocos de Caldas; Kelecom, Alphonse, E-mail: akelecom@id.uff.br [Universidade Federal Fluminense (GETA/LARARA-PLS/UFF), Niteroi, RJ (Brazil). Laboratorio de Radiobiologia e Radiometria Pedro Lopes dos Santos. Grupo de Estudos em Temas Ambientais; Mortagua, Valter, E-mail: Valter@inb.gov.br [Usina de lnterlagos (USIN), Sao Paulo, SP (Brazil). Coordenacao

2013-07-01

In the year 2007, ICRP published a set of recommendations (The 2007 Recommendations of the International Commission on Radiological Protection, Publication 103), which changed some important concepts. This work aims to compare the Brazilian radiation protection basic norm with the new ICRP recommendations, by checking the existing differences. The main difference between ICRP publication 60 and ICRP publication 103 is the changing of the concept of protection based on process, by using the concepts of practice and intervention, to the protection based in the exposition situation, by using the concepts of planned exposure, emergency and existing situation. Other important difference lies in the values of the radiation and tissue weighting factors, in the quantities equivalent and effective dose, and updating the radiation detriment based on the latest available scientific information of the biology and physics of radiation exposure. At last, the demonstration of the environment radiation protection must be clear, and this concept is not found in Brazilian nuclear legislation. Also some similarities were found. The fundamental principles of the Brazilian norms are the same as that of ICRP 103, which are the justification principle, the optimization principle and the application of dose limits. The individual effective dose limit of Brazilian norm is the same of the ICRP 103, established as 20 mSv per year. In order to adequate the Brazilian norm it is necessary to change its concept of protection and the values of radiation and tissue weighting, and updating the radiation detriment, besides making clear the concept of protection of the environment. It is important to notice that although the Brazilian norm is not in complete agreement with all international recommendations, it must be completely followed as the norm which is in use in the country. (author)

Board advice following publication of the 1990 Recommendations of ICRP

International Nuclear Information System (INIS)

1991-11-01

The International Commission on Radiological Protection (ICRP) has published new Recommendations and the Board has a statutory duty to advise Government and those with responsibilities for radiation protection on the acceptability to and the applicability in the UK of those Recommendations. The Board wishes to consult widely before finalising the advice which is proposed in this document. In general, the Board endorses the conceptual framework for radiological protection recommended by ICRP. In particular, the distinction between practices and intervention is useful and is consistent with the way in which the Board has presented its recent advice. A major new concept is that of a constraint. The Board believes that the introduction of constraints provides a powerful method for improving protection against ionising radiation. The advice in this consultative document is for maximum generic values of dose constraints for both workers and the public. Finally the Board proposes to endorse the use of the radiological quantities recommended by ICRP. (author)

The implications of ICRP publication (60) 1990 for public exposure to natural radiation

International Nuclear Information System (INIS)

Laughlin, J.Mc.

1992-01-01

The implications of the new ICRP recommendations on the control of public exposure to natural radiation are described. As ICRP differentiates between Practices and Interventions the application of the basic recommendations in the case of natural radiation exposures will be discussed in this context. Particular emphasis will be placed on public exposure to indoor radon with some discussion on situations in which occupational and public exposure to this source occur together. This major source of public exposure i discussed in relation to both ICRP 60 and ICRP 39. Some of the difficulties that the new recommendations may give rise to in the management of natural radiation exposures are discussed. One of the major changes in the new recommendations concerns the area of risk. This will be briefly discussed as regards the ways in which the risk arising from public exposure to natural radiation may be assessed. (author)

Bridging the Gap between RF and Optical Patch Antenna Analysis via the Cavity Model.

Science.gov (United States)

Unal, G S; Aksun, M I

2015-11-02

Although optical antennas with a variety of shapes and for a variety of applications have been proposed and studied, they are still in their infancy compared to their radio frequency (rf) counterparts. Optical antennas have mainly utilized the geometrical attributes of rf antennas rather than the analysis tools that have been the source of intuition for antenna engineers in rf. This study intends to narrow the gap of experience and intuition in the design of optical patch antennas by introducing an easy-to-understand and easy-to-implement analysis tool in rf, namely, the cavity model, into the optical regime. The importance of this approach is not only its simplicity in understanding and implementation but also its applicability to a broad class of patch antennas and, more importantly, its ability to provide the intuition needed to predict the outcome without going through the trial-and-error simulations with no or little intuitive guidance by the user.

The work of committee 2 of ICRP on internal dosimetry

International Nuclear Information System (INIS)

Stather, J.W.

2005-01-01

Full text: Over the last few years the Task Group of Committee 2 of ICRP on Internal Dosimetry (INDOS), in conjunction with the Task Group on Dose Calculations (DOCAL), has prepared a series of publications that have given dose coefficients for intakes of radionuclides by infants, children and adults. The most recent publications have been Publication 88 that gives doses to the embryo, fetus and newborn child from intakes of radionuclides by the mother and Publication 94 that will give doses to the newborn child from intakes of radionuclides in mothers' milk. These documents have completed the programme of work of Committee 2 on dose coefficients for members of the public. The emphasis of work on internal dosimetry by Committee 2 is now concerned with occupational exposure. This is will take into account recent advice from ICRP, including the new 2005 Recommendations of ICRP which are expected to provide revised tissue weighting factors for the calculation of effective dose. In addition ICRP has issued Publication 89 on Basic Anatomical and Physiological Data for use in Radiological Protection and in addition will have published a new Human Alimentary Tract Model (HATM). It will have implemented a human phantom for dose calculations based upon medical imaging data and updated radionuclide decay data; superseding Publication 38. In addition, the systemic models for a number of elements are being revised to take account of more recent data, and the lung clearance characteristics of a wide range of compounds relevant to occupational exposure are being reviewed. It is intended to replace Publications 30 and 68 that give biokinetic data and dose coefficients for intakes of radionuclides and Publications 54 and 78 that give information for bioassay interpretation, with a single series of publications. This series will cover both dosimetry and data for bioassay interpretation. The first report will cover radionuclides of the 31 elements covered in the series of

Electrical characterization of the JET A2 antenna: Comparison of model with measurements

International Nuclear Information System (INIS)

Ryan, P.M.; Goulding, R.H.; Bhatnagar, V.; Kaye, A.; Wade, T.

1993-01-01

The JET experiment is replacing its previous (Al) antennas with upgraded designs (A2) for its upcoming ''pumped diverter'' operation. These antennas are more directional than the previous two-strap Al antennas when operated as a phased array. The frequency range is 23 to 57 MHz. A full-scale low power ''flat'' mockup was tested at JET; strap lengths were adjusted to give balanced operation with resonance at 42 MHz. A second mockup module, differing only slightly from the original, was subsequently fabricated and both modules were sent to ORNL for additional measurements and to test the operation of the power compensator circuit. There are benefits to using a transmission line model to characterize coupled antenna systems, primarily in the ease of incorporating the antennas into the overall analysis of the transmission, tuning, and matching system. The characteristics of the array under arbitrary phasing are also needed for the design, analysis, and control of the power compensator. There are aspects of the JET A2 antenna geometry that differ considerably from previously modeled cases. Each transmission line feeds two poloidally-stacked straps connected in parallel. The parallel straps present different electrical loads at the match point due to geometrical differences. Currents in one section of the strap influence other sections of the same strap as well as in neighboring straps due to internal inductive coupling. The lengths of the inner and outer straps differ; moreover, the inner straps are fed from ports located behind the outer straps, resulting in increased coupling between the inner and outer straps due to the long feed lines and in greater disparity between the electrical loads presented at the inner and outer feed ports. The present effort is to determine whether a more general coupled transmission line model can characterize the array response with sufficient accuracy for the purpose of design and analysis

The recommendations of the ICRP: the reasons for a change

International Nuclear Information System (INIS)

Sugier, A.; Nenot, J.C.; Lecomte, J.F.

2005-01-01

Since its foundation in 1928, the International Commission on Radiological Protection (ICRP) has regularly produced recommendations on the protection against ionising radiation; these recommendations are currently taken up by international organisations and by states. Since 1990, date of issue of the most recent recommendations (Publication 60), advances in scientific knowledge, technical developments, feedback and desire to meet modern societal developments, have incited the ICRP to modify its system of protection. The latest draft, which was recently presented openly for consultation and proposals, is described and discussed. (author)

Three-dimensional modelling and numerical optimisation of the W7-X ICRH antenna

Energy Technology Data Exchange (ETDEWEB)

Louche, F., E-mail: fabrice.louche@rma.ac.be [Laboratoire de physique des plasmas de l’ERM, Laboratorium voor plasmafysica van de KMS (LPP-ERM/KMS), Ecole Royale Militaire, Koninklijke Militaire School, Brussels (Belgium); Křivská, A.; Messiaen, A.; Ongena, J. [Laboratoire de physique des plasmas de l’ERM, Laboratorium voor plasmafysica van de KMS (LPP-ERM/KMS), Ecole Royale Militaire, Koninklijke Militaire School, Brussels (Belgium); Borsuk, V. [Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Juelich (Germany); Durodié, F.; Schweer, B. [Laboratoire de physique des plasmas de l’ERM, Laboratorium voor plasmafysica van de KMS (LPP-ERM/KMS), Ecole Royale Militaire, Koninklijke Militaire School, Brussels (Belgium)

2015-10-15

Highlights: • A simplified version of the ICRF antenna for the stellarator W7-X has been modelled with the 3D electromagnetic software Microwave Studio. This antenna can be tuned between 25 and 38 MHz with the help of adjustable capacitors. • In previous modellings the front of the antenna was modelled with the help of 3D codes, while the capacitors were modelled as lumped elements with a given DC capacitance. As this approach does not take into account the effect of the internal inductance, a MWS model of these capacitors has been developed. • The initial geometry does not permit the operation at 38 MHz. By modifying some geometrical parameters of the front face, it was possible to increase the frequency band of the antenna, and to increase (up to 25%) the maximum coupled power accounting for the technical constraints on the capacitors. • The W7-X ICRH antenna must be operated at 25 and 38 MHz, and for various toroidal phasings of the strap RF currents. Due to the considered duty cycle it is shown that thanks to a special procedure based on minimisation techniques, it is possible to define a satisfactory optimum geometry in agreement with the specifications of the capacitors. • The various steps of the optimisation are validated with TOPICA simulations. For a given density profile the RF power coupling expectancy can be precisely computed. - Abstract: Ion Cyclotron Resonance Heating (ICRH) is a promising heating and wall conditioning method considered for the W7-X stellarator and a dedicated ICRH antenna has been designed. This antenna must perform several tasks in a long term physics programme: fast particles generation, heating at high densities, current drive and ICRH physics studies. Various minority heating scenarios are considered and two frequency bands will be used. In the present work a design for the low frequency range (25–38 MHz) only is developed. The antenna is made of 2 straps with tap feeds and tuning capacitors with DC capacitance in

Radio antennas

Science.gov (United States)

Gibson, S. W.

This book is concerned with providing an explanation of the function of an antenna without delving too deeply into the mathematics or theory. The characteristics of an antenna are examined, taking into account aspects of antenna radiation, wave motion on the antenna, resistance in the antenna, impedance, the resonant antenna, the effect of the ground, polarization, radiation patterns, coupling effects between antenna elements, and receiving vs. transmitting. Aspects of propagation are considered along with the types of antennas, transmission lines, matching devices, questions of antenna design, antennas for the lower frequency bands, antennas for more than one band, limited space antennas, VHF antennas, and antennas for 20, 15, and 10 meters. Attention is given to devices for measuring antenna parameters, approaches for evaluating the antenna, questions of safety, and legal aspects.

The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR

Energy Technology Data Exchange (ETDEWEB)

Kim, So Ra; Min, Byung Il; Park, Kihyun; Yang, Byung Mo; Suh, Kyung Suk [Nuclear Environmental Safety Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-12-15

The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment.

The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR

International Nuclear Information System (INIS)

Kim, So Ra; Min, Byung Il; Park, Kihyun; Yang, Byung Mo; Suh, Kyung Suk

2016-01-01

The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment

Broadband standard dipole antenna for antenna calibration

Science.gov (United States)

Koike, Kunimasa; Sugiura, Akira; Morikawa, Takao

1995-06-01

Antenna calibration of EMI antennas is mostly performed by the standard antenna method at an open-field test site using a specially designed dipole antenna as a reference. In order to develop broadband standard antennas, the antenna factors of shortened dipples are theoretically investigated. First, the effects of the dipole length are analyzed using the induced emf method. Then, baluns and loads are examined to determine their influence on the antenna factors. It is found that transformer-type baluns are very effective for improving the height dependence of the antenna factors. Resistive loads are also useful for flattening the frequency dependence. Based on these studies, a specification is developed for a broadband standard antenna operating in the 30 to 150 MHz frequency range.

The new recommendations of ICRP and their possible consequences for operating nuclear installations

International Nuclear Information System (INIS)

Lorenz, Bernd; Hesse, Johannes; Schwarz, Wolfgang; Kapteinat, Heinzpeter; Holl, Matthias

2008-01-01

Full text: After an extensive and very open debate within the Radiation Protection Community the new recommendations of the ICRP on the basic principles of radiation protection have been issued in 2007. The German nuclear industry has watched the process intensively and tried to bring in their large amount of experience from the daily radiation protection practice in numerous nuclear installations. Notably the ICRP seemed to follow some of the comments given by those experienced operators. The ICRP key message 'stability and continuity' is highly welcomed by industry. The dose levels resulting from well managed operations today are far below the dose limits due to a working system of ALARA thinking and doing. The basic principles of radiation protection as pointed out by ICRP decades ago have been proven to be an effective tool and are an essential part of the legal system of most countries with developed nuclear industries. Unfortunately, not all of the comments of the experienced operators have been considered to the desirable extend. A mayor point of criticism is the central role ICRP devoted to the use of dose constraints for any source. Dose constraints do play a role in today's practice of radiation protection but they have been rather supplementary than central in the system. The idea that for all sources, and there might be Hundreds or Thousands sometimes very tiny sources in a practice, a dose constraint shall exist sounds quite inappropriate. Another example which might disturb the great vision of 'stability and continuity' is the change of ICRP into a different view on protection. Instead of processes now situations are in the focus. There are some doubts about the benefits of such a move. People will always ask if there is a change of content when using a different terminology. A lot of fruitless discussions will probably result. Nevertheless, in spite of some criticism the new ICRP will contribute to strengthen the protection regime and industry will

An image-based skeletal dosimetry model for the ICRP reference adult male-internal electron sources

International Nuclear Information System (INIS)

Hough, Matthew; Johnson, Perry; Bolch, Wesley; Rajon, Didier; Jokisch, Derek; Lee, Choonsik

2011-01-01

In this study, a comprehensive electron dosimetry model of the adult male skeletal tissues is presented. The model is constructed using the University of Florida adult male hybrid phantom of Lee et al (2010 Phys. Med. Biol. 55 339-63) and the EGSnrc-based Paired Image Radiation Transport code of Shah et al (2005 J. Nucl. Med. 46 344-53). Target tissues include the active bone marrow, associated with radiogenic leukemia, and total shallow marrow, associated with radiogenic bone cancer. Monoenergetic electron emissions are considered over the energy range 1 keV to 10 MeV for the following sources: bone marrow (active and inactive), trabecular bone (surfaces and volumes), and cortical bone (surfaces and volumes). Specific absorbed fractions are computed according to the MIRD schema, and are given as skeletal-averaged values in the paper with site-specific values reported in both tabular and graphical format in an electronic annex available from http://stacks.iop.org/0031-9155/56/2309/mmedia. The distribution of cortical bone and spongiosa at the macroscopic dimensions of the phantom, as well as the distribution of trabecular bone and marrow tissues at the microscopic dimensions of the phantom, is imposed through detailed analyses of whole-body ex vivo CT images (1 mm resolution) and spongiosa-specific ex vivo microCT images (30 μm resolution), respectively, taken from a 40 year male cadaver. The method utilized in this work includes: (1) explicit accounting for changes in marrow self-dose with variations in marrow cellularity, (2) explicit accounting for electron escape from spongiosa, (3) explicit consideration of spongiosa cross-fire from cortical bone, and (4) explicit consideration of the ICRP's change in the surrogate tissue region defining the location of the osteoprogenitor cells (from a 10 μm endosteal layer covering the trabecular and cortical surfaces to a 50 μm shallow marrow layer covering trabecular and medullary cavity surfaces). Skeletal

An image-based skeletal dosimetry model for the ICRP reference adult male-internal electron sources

Energy Technology Data Exchange (ETDEWEB)

Hough, Matthew; Johnson, Perry; Bolch, Wesley [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL (United States); Rajon, Didier [Department of Neurosurgery, University of Florida, Gainesville, FL (United States); Jokisch, Derek [Department of Physics and Astronomy, Francis Marion University, Florence, SC (United States); Lee, Choonsik, E-mail: wbolch@ufl.edu [Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD (United States)

2011-04-21

In this study, a comprehensive electron dosimetry model of the adult male skeletal tissues is presented. The model is constructed using the University of Florida adult male hybrid phantom of Lee et al (2010 Phys. Med. Biol. 55 339-63) and the EGSnrc-based Paired Image Radiation Transport code of Shah et al (2005 J. Nucl. Med. 46 344-53). Target tissues include the active bone marrow, associated with radiogenic leukemia, and total shallow marrow, associated with radiogenic bone cancer. Monoenergetic electron emissions are considered over the energy range 1 keV to 10 MeV for the following sources: bone marrow (active and inactive), trabecular bone (surfaces and volumes), and cortical bone (surfaces and volumes). Specific absorbed fractions are computed according to the MIRD schema, and are given as skeletal-averaged values in the paper with site-specific values reported in both tabular and graphical format in an electronic annex available from http://stacks.iop.org/0031-9155/56/2309/mmedia. The distribution of cortical bone and spongiosa at the macroscopic dimensions of the phantom, as well as the distribution of trabecular bone and marrow tissues at the microscopic dimensions of the phantom, is imposed through detailed analyses of whole-body ex vivo CT images (1 mm resolution) and spongiosa-specific ex vivo microCT images (30 {mu}m resolution), respectively, taken from a 40 year male cadaver. The method utilized in this work includes: (1) explicit accounting for changes in marrow self-dose with variations in marrow cellularity, (2) explicit accounting for electron escape from spongiosa, (3) explicit consideration of spongiosa cross-fire from cortical bone, and (4) explicit consideration of the ICRP's change in the surrogate tissue region defining the location of the osteoprogenitor cells (from a 10 {mu}m endosteal layer covering the trabecular and cortical surfaces to a 50 {mu}m shallow marrow layer covering trabecular and medullary cavity surfaces). Skeletal

Handbook of antenna technologies

CERN Document Server

Liu, Duixian; Nakano, Hisamatsu; Qing, Xianming; Zwick, Thomas

2016-01-01

The Handbook of Antenna Technologies aims to present the rapid development of antenna technologies, particularly in the past two decades, and also showcasing the newly developed technologies and the latest applications. The handbook will provide readers with the comprehensive updated reference information covering theory, modeling and optimization methods, design and measurement, new electromagnetic materials, and applications of antennas. The handbook will widely cover not only all key antenna design issues but also fundamentals, issues related to antennas (transmission, propagation, feeding structure, materials, fabrication, measurement, system, and unique design challenges in specific applications). This handbook will benefit the readers as a full and quick technical reference with a high-level historic review of technology, detailed technical descriptions and the latest practical applications.

Radiation Safety Analysis In The NFEC For Assessing Possible Implementation Of The ICRP-60 Standard

International Nuclear Information System (INIS)

Yowono, I.

1998-01-01

Radiation safety analysis of the 3 facilities in the nuclear fuel element center (NFEC) for assessing possible implementation of the ICRP-60 standard has been done. The analysis has covered the radiation dose received by workers, dose rate in the working area, surface contamination level, air contamination level and the level of radioactive gas release to the environment. The analysis has been based on BATAN regulation and ICRP-60 standard. The result of the analysis has showed that the highest radiation dose received has been found to be only around 15% of the set value in the ICRP-60 standard and only 6% of the set value in the BATAN regulation. Thus the ICRP-60 as radiation safety standard could be implemented without changing the laboratory design

Present capabilities and new developments in antenna modeling with the numerical electromagnetics code NEC

Energy Technology Data Exchange (ETDEWEB)

Burke, G.J.

1988-04-08

Computer modeling of antennas, since its start in the late 1960's, has become a powerful and widely used tool for antenna design. Computer codes have been developed based on the Method-of-Moments, Geometrical Theory of Diffraction, or integration of Maxwell's equations. Of such tools, the Numerical Electromagnetics Code-Method of Moments (NEC) has become one of the most widely used codes for modeling resonant sized antennas. There are several reasons for this including the systematic updating and extension of its capabilities, extensive user-oriented documentation and accessibility of its developers for user assistance. The result is that there are estimated to be several hundred users of various versions of NEC world wide. 23 refs., 10 figs.

Basic concepts and assumptions behind the ICRP recommendations

International Nuclear Information System (INIS)

Lindell, B.

1981-03-01

The paper gives a review of the current radiation protection recommendations by the International Commission on Radiological Protection (ICRP). It discusses concepts like stochastic effects, radiation detriments, collective dose, dose equivalent and dose limits. (G.B.)

Efficient Placement of Directional Antennas

Energy Technology Data Exchange (ETDEWEB)

Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory

2010-09-20

Directional antenna is an technology for the proliferation of wireless networks. In centralized wireless network, wireless devices communicate through base stations. Directed antennas are placed on base stations and form a backbone of communication. The communication between base stations and wireless devices can be interfered due to a large number of wireless device. Methodically positioning and orienting directed antennas can help to reduce the interference while saving energy. An integer linear programming is developed for siting and directing antennas on multiple base stations, and this formulation can be extended to model non-overlapping channels. Through the integer programming formulation, optimal antenna positions can be used to analyze the performance of directed antennas with different parameters like the number base stations and the number of non-overlapping channels.

The new ICRP recommendations

International Nuclear Information System (INIS)

Schlesinger, T.

1977-01-01

The new ICRP recommendations are based on the concept of risk. The doses received by workers have to be justified and kept as low as practically achievable. The acceptable annual occupational risk is of the order of 10 -4 . This corresponds to an average annual dose equivalent of about 5 mSv(0.5 Rem). The annual dose equivalent limit for whole body irradiation will remain 50 mSv/year (5 Rem/year) provided that the average is about 1/10th of this value. The concept of the critical organ is abandoned and is replaced by the concept of equidetriment. (author)

Statistical Modeling of Antenna: Urban Equipment Interactions for LTE Access Points

Directory of Open Access Journals (Sweden)

Xin Zeng

2012-01-01

Full Text Available The latest standards for wireless networks such as LTE are essentially based on small cells in order to achieve a large network capacity. This applies for antennas to be deployed at street level or even within buildings. However, antennas are commonly designed, simulated, and measured in ideal conditions, which is not the real situation for most applications where antennas are often deployed in proximity to objects acting as disturbers. In this paper, three conventional wireless access point scenarios (antenna-wall, antenna-shelter, and antenna lamppost are investigated for directional or omnidirectional antennas. The paper first addresses the definition of three performance indicators for such scenarios and secondly uses such parameters towards the statistical analysis of the interactions between the wall and the antennas.

Performance prediction of high Tc superconducting small antennas using a two-fluid-moment method model

Science.gov (United States)

Cook, G. G.; Khamas, S. K.; Kingsley, S. P.; Woods, R. C.

1992-01-01

The radar cross section and Q factors of electrically small dipole and loop antennas made with a YBCO high Tc superconductor are predicted using a two-fluid-moment method model, in order to determine the effects of finite conductivity on the performances of such antennas. The results compare the useful operating bandwidths of YBCO antennas exhibiting varying degrees of impurity with their copper counterparts at 77 K, showing a linear relationship between bandwidth and impurity level.

Organ burdens and excretion rates of inhaled uranium - computations using ICRP model

International Nuclear Information System (INIS)

Abani, M.C.; Murthy, K.B.S.; Sunta, C.M.

1988-01-01

Uranium being a highly toxic material, proper estimation of the body burden is very important. During manufacture of uranium fuel, it is likely to enter the body by inhalation. By the body burden and excretion measurements, one should be able to assess whether the intake is within the safe limits or not. This is possible if one performs theoretical calculations and estimates the amount of uranium which builds up in the body as a function of time. Similarly theoretical estimates in case of excretion have to be made. For this purpose, a computer programme has been developed to find out organ burdens and excretion rates resulting from exposure to a radioactive nuclide. ICRP-30 lung model has been used and cases of single instantaneous inhalation of 1 ALI as well as inhalation at a steady rate of ALI/365 per day have been considered. Using this programme, results for uranium aerosols of classes D, W and Y and sizes 0.2, 1 and 5 microns are generated by ND computers in tabular as well as graphical forms. These will be useful in conjunction with body burden measurements by direct counting or excretion analysis. (author). 7 tabs., 56 figs

Diagnostic Reference Levels in the 1990 and 1996 Recommendations of the ICRP (invited paper)

International Nuclear Information System (INIS)

Drexler, G.

1998-01-01

A review of and some comments on the paragraphs in the ICRP Publications 60 and 73 are presented, which are relevant to diagnostic reference doses. The content of the statements is traced back by approximately 50 years when ICRP's preoccupation with the future health and well-being of the population is reflected in guidance for characterisation of 'normal operational conditions'. The early ICRP levels of reference doses are compared with the values currently discussed to demonstrate the importance of diagnostic reference doses in the process of optimisation and to show the importance of a continuous review and update of these levels. (author)

Aspects of ICRP 60 and ICRU 47 relevant to individual monitoring of external exposure

International Nuclear Information System (INIS)

Dietze, G.; Menzel, H.G.

1994-01-01

Exposure limits recommended by the ICRP and used in regulations are expressed in risk related quantities such as effective dose or effective dose equivalent. Operational quantities such as ambient dose equivalent or personal dose equivalent are defined in phantoms and are designed to give reasonable estimates of exposure limiting quantities. The readings of individual dosemeters are calibrated in terms of operational quantities. The international commissions involved in the definition of risk related quantities (ICRP) and operational quantities (ICRU) have introduced various new definitions and modifications to previous quantities used in their respective publications ICRP 60 and ICRU 39, ICRU 47. The consequences of these alterations for the relationships between quantities within the hierarchy have to be examined and the new quantitative relationships (conversion coefficients) between basic physical radiation quantities such as particle fluence or air kerma and the new quantities have to be evaluated. In 1992, the ICRP and ICRU charged a joint task group with addressing these tasks with a view to revising ICRP Publication 51. This paper presents an outline for the subject of the report to be prepared by the task group. An introduction to the new phantom-based quantities is given and conceptional differences between the newly introduced and the previous quantities are discussed. (author)

A Modal Approach to Compact MIMO Antenna Design

Science.gov (United States)

Yang, Binbin

MIMO (Multiple-Input Multiple-Output) technology offers new possibilities for wireless communication through transmission over multiple spatial channels, and enables linear increases in spectral efficiency as the number of the transmitting and receiving antennas increases. However, the physical implementation of such systems in compact devices encounters many physical constraints mainly from the design of multi-antennas. First, an antenna's bandwidth decreases dramatically as its electrical size reduces, a fact known as antenna Q limit; secondly, multiple antennas closely spaced tend to couple with each other, undermining MIMO performance. Though different MIMO antenna designs have been proposed in the literature, there is still a lack of a systematic design methodology and knowledge of performance limits. In this dissertation, we employ characteristic mode theory (CMT) as a powerful tool for MIMO antenna analysis and design. CMT allows us to examine each physical mode of the antenna aperture, and to access its many physical parameters without even exciting the antenna. For the first time, we propose efficient circuit models for MIMO antennas of arbitrary geometry using this modal decomposition technique. Those circuit models demonstrate the powerful physical insight of CMT for MIMO antenna modeling, and simplify MIMO antenna design problem to just the design of specific antenna structural modes and a modal feed network, making possible the separate design of antenna aperture and feeds. We therefore develop a feed-independent shape synthesis technique for optimization of broadband multi-mode apertures. Combining the shape synthesis and circuit modeling techniques for MIMO antennas, we propose a shape-first feed-next design methodology for MIMO antennas, and designed and fabricated two planar MIMO antennas, each occupying an aperture much smaller than the regular size of lambda/2 x lambda/2. Facilitated by the newly developed source formulation for antenna stored

Generic Screening Models for Assessing Exposures to the Public and ICRP Reference Animals and Plants

Energy Technology Data Exchange (ETDEWEB)

Yankovich, Tamara L.; Proehl, Gerhard; Telleria, Diego [International Atomic Energy Agency, P.O. Box 100, 1400 Vienna (Austria); Berkovskyy, Volodymyr [Ukrainian Radiation Protection Institute (RPI), 53, Melnikova Street, 04050, Kiev (Ukraine)

2014-07-01

Exposure', and 'Generic Models for Use in Assessing the Impact of Radioactive Discharges', respectively. Volume 3 is currently being drafted and will provide coefficients that enable screening assessments for the ICRP Reference Animals and Plants (RAPs), based on the models presented in ICRP publications 108 and 114. Through the application of the same models for dispersion of radionuclides in the atmosphere and in water bodies, standardized input parameters, assumptions and approaches that are being applied to develop screening coefficients, an integrated approach is being established that can be used to estimate exposures to people and the environment and to demonstrate protection, in accordance with SF-1. This integrated approach will allow the establishment of relationships of exposures to people, and to flora and fauna for the same levels of environmental radioactivity. This paper provides an update of the current status of the SRS 19 update. (authors)

Development of ceramic-free antenna feeder

International Nuclear Information System (INIS)

Moriyama, S.; Kimura, H.; Fujii, T.; Saigusa, M.; Arai, H.

1994-01-01

We have proposed a ceramics-free antenna feeder line employing a ridged waveguide as a local support for IC antenna of next-generation tokamaks. One fourth mock-up model of the all metal waveguide designed for the ITER ICRF system is fabricated and electrical characteristics of the model including the coaxial line - waveguide converter are measured. Power reflection coefficient of the model including the coax-waveguide converter to the input coaxial line is estimated to be less than 15% below the cut-off frequency of 107 MHz and less than 3% above the cut-off frequency. It is found that this ceramics-free antenna support employing a ridged waveguide is quite available for IC antenna of next-generation tokamaks. (author)

ICRP 2015. International symposium on the radiation protection system. Report and reflection on a significant symposium

International Nuclear Information System (INIS)

Lorenz, Bernd

2016-01-01

The ICRP international symposium on the radiation protection system provides always extensive information on new developments in radiation protection. The ICRP 2105 discussed the following issues: radiation effects of low dose irradiation, dose coefficients for internal and external exposures, radiation protection in nuclear medicine, application of ICRP recommendations, environmental protection, studies on existing exposure situations, medical radiation protection today, science behind radiation doses, new developments in radiation effects, and ethics in radiation protection.

Foetal dosimetry--is the ICRP dosimetric system for humans now complete?

Energy Technology Data Exchange (ETDEWEB)

Jones, Steve [Westlakes Research Institute, Cumbria (United Kingdom)

2002-03-01

Internal dosimetry is possibly the most complex area of science associated with radiological protection, and has a long history. Primary control of internal exposure now relied on control of annual intakes rather than limitation of organ burdens. Although it took nearly a decade for regulations and hence the practice of occupational radiation protection to fully adopt the new recommendations, the new dosimetric concepts were quite rapidly adopted in the assessment of public exposure because the new methods provided a more natural means of assessing the significance of exposure to a combination of external and internal exposure involving a number of different radionuclides. As a result, following the ICRP's initial publication of dosimetric models for occupational exposure, adaptations became available to cover environmental exposure, including the exposure of infants and children. Increasingly sophisticated biokinetic and dosimetric models have now been developed which, together with the welcome availability of dose per unit intake factors in CD-ROM form make it easy for the radiation protection practitioner to assess committed effective doses, and committed equivalent doses to individual organs, to occupationally exposed adults and environmentally exposed infants, children and adults. The inability to readily assess doses to the developing foetus has, however, long been perceived as a significant gap in knowledge with implications for the study of childhood leukaemia in the vicinity of nuclear installations and possibly also the control of occupational exposure for women of child-bearing age. The first systematic assessment of doses to the foetus was in connection with the study of childhood leukaemia in the vicinity of Sellafield in the UK, for which preliminary models were developed. Since that time a few publications giving guidance on the calculation of foetal doses have emerged and more sophisticated assessments of foetal dose have been reported

Development of derived limits for radiological protection against ionizing radiation based on ICRP-60 recommendations

International Nuclear Information System (INIS)

Jang, S. Y.; Lee, B. S.

1999-01-01

Derived limits such as the Annual Limit on Intake (ALI), Derived Air Concentration (DAC) and Effluent Concentration Limit (ECL) for radiological protection against ionizing radiation based on ICRP-60 recommendations were calculated using dose limits and committed effective dose coefficients of the basic Safety Standards of IAEA (i.e. safety series 115; BSS-96). Derived limits regarding occupational exposure were derived using methodologies of ICRP-61 and dose limit stated in ICRP -60. ECL in air and water for the control of radioactive discharge into the environment were derived using methodologies of 10 CFR part 20 and dose limit stated in ICRP-60. In order to analyze the impact of implementing derived limits on nuclear facilities, the derived values in this study were compared with those prescribed in 10 CFR part 20 as well as the Maximum Permissible Concentrations (MPC) of Notice No. 98-12 of the Ministry of Science and Technology (MOST). According to the comparison results, ECLs in air and water for the control of radioactive discharge into the environment in this study are shown to have lower values (i.e. more conservative), for most part, than those in Notice No. 98-12. These differences are due to the reduction of dose limit, adoption of a weighting factor for age-dependency in dose coefficients, and application of new respiratory tract model and bio-kinetics model. Especially, for uranium elements (i.e., 235 U, 238 U, etc.), which are governing ones in the nuclear fuel industries, ECLs in water are approximately a magnitude in the order of two lower than those in Notice No. 98-12. These are attributable to the adoption of a weighting factor for age-dependency in dose coefficients, newly recommended dose coefficients for ingestion pathway, and reduction of dose limit. It was found out that the differences in ECLs in water for uranium elements originated mostly from ingestion dose coefficients recommended by BSS-96. (author). 6 refs., 2 tabs., 5 figs

Consideration of the ICRP 2006 revised tissue weighting factors on age-dependent values of the effective dose for external photons

Science.gov (United States)

Lee, Choonsik; Lee, Choonik; Han, Eun Young; Bolch, Wesley E.

2007-01-01

The effective dose recommended by the International Commission on Radiological Protection (ICRP) is the sum of organ equivalent doses weighted by corresponding tissue weighting factors, wT. ICRP is in the process of revising its 1990 recommendations on the effective dose where new values of organs and tissue weighting factors have been proposed and published in draft form for consultation by the radiological protection community. In its 5 June 2006 draft recommendations, new organs and tissues have been introduced in the effective dose which do not exist within the 1987 Oak Ridge National Laboratory (ORNL) phantom series (e.g., salivary glands). Recently, the investigators at University of Florida have updated the series of ORNL phantoms by implementing new organ models and adopting organ-specific elemental composition and densities. In this study, the effective dose changes caused by the transition from the current recommendation of ICRP Publication 60 to the 2006 draft recommendations were investigated for external photon irradiation across the range of ICRP reference ages (newborn, 1-year, 5-year, 10-year, 15-year and adult) and for six idealized irradiation geometries: anterior-posterior (AP), posterior-anterior (PA), left-lateral (LLAT), right-lateral (RLAT), rotational (ROT) and isotropic (ISO). Organ-absorbed doses were calculated by implementing the revised ORNL phantoms in the Monte Carlo radiation transport code, MCNPX2.5, after which effective doses were calculated under the 1990 and draft 2006 evaluation schemes of the ICRP. Effective doses calculated under the 2006 draft scheme were slightly higher than estimated under ICRP Publication 60 methods for all irradiation geometries exclusive of the AP geometry where an opposite trend was observed. The effective doses of the adult phantom were more greatly affected by the change in tissue weighting factors than that seen within the paediatric members of the phantom series. Additionally, dose conversion

Modeling and Control of the Redundant Parallel Adjustment Mechanism on a Deployable Antenna Panel

Directory of Open Access Journals (Sweden)

Lili Tian

2016-10-01

Full Text Available With the aim of developing multiple input and multiple output (MIMO coupling systems with a redundant parallel adjustment mechanism on the deployable antenna panel, a structural control integrated design methodology is proposed in this paper. Firstly, the modal information from the finite element model of the structure of the antenna panel is extracted, and then the mathematical model is established with the Hamilton principle; Secondly, the discrete Linear Quadratic Regulator (LQR controller is added to the model in order to control the actuators and adjust the shape of the panel. Finally, the engineering practicality of the modeling and control method based on finite element analysis simulation is verified.

Implications of the 1990 ICRP recommendations for the mining industry

International Nuclear Information System (INIS)

Fry, R.M.

1992-01-01

Significant radiological protection problems arise in the mining and processing of uranium and thorium bearing ores, beach sands and other materials that have enhanced levels of uranium (e.g. phosphate). They are at their most extreme in the underground mining of uranium. Under the new ICRP 60 occupational dose limits it may be necessary to subject virtually all mining operations to some degree of radiological surveillance. There are three principal modes of radiation exposure in uranium mining operations: gamma rays, an external whole body radiation hazard; the inhalation of radon daughter products; and the inhalation of ore dust containing the long-lived alpha emitting daughter products of uranium, principally 230Th and 226Ra. A number of the new recommendations in ICRP60 considered to have significant implications for the mining industry in general and the above mentioned issues in particular are discussed. These include the definition of occupational exposure occupational dose limit, the review of the radon dose limits, the system of radiological protection. The major conclusions and recommendation of the IAEA Technical Committee to Explore the Impact of the new ICRP Occupational Dose Limits in the operation of underground mines are also summarized. 18 refs., 1 tab

Antenna Miniaturization in Complex Electromagnetic Environments

DEFF Research Database (Denmark)

Zhang, Jiaying

improved compared to the 2-D planar electrically small loop antennas. Measurement Techniques for ESAs In this dissertation we proposed two novel measurement techniques for electrically small antennas. A modified Wheeler cap method for the radiation efficiency measurement of balanced electrically small....... Moreover, the modified Wheeler cap method for measurements of small antennas in complex environments is further developed. A cable-free impedance and gain measurement technique for electrically small antennas is also proposed. The electromagnetic model of this technique is derived by using the spherical...... wave expansion, and it is valid for arbitrary electrically small AUT at arbitrary distances between the probe and AUT. The whole measurement setup is modeled by the cascade of three coupled multipleort networks. The electromagnetic model, the simulation results, and the obtained measurement results...

New ICRP recommendations 2005: without full consensus?

International Nuclear Information System (INIS)

Novakovic, M.

2005-01-01

Ionising radiation is viewed as one of the most studied of all known carcinogens. Over the last 50 years Recommendations of International Commission for Radiological Protection (ICRP) have been changed regularly every 10 years. At the beginning these changes were significant, sometimes even radical, according to quick acquiring of new scientific evidence on physical, biological and health effects of radiation. In order to handle each new situation evolution of the radiation protection system has been extended and new portions have been added (the ubiquitous exposure of public to radon gas and its progeny, and the need to develop an appropriate response to emergency situations, increasing social desire to participate in decision making processes, concern for the protection of non-human species and environment), that resulted in a system that is increasingly complicated. Over the last few years very broad discussions of major radiation protection concepts have been encouraged by the ICRP in order to achieve consensus on a more operational and coherent system of radiation protection elaborated in a transparent fashion, and presented in readily understandable terms. This process for the first time involves a broad spectrum of stake holders in these discussions. It is further assumed that these debates will eventually result in consensus on the basis for the next round of ICRP general recommendations, probably in the 2005. While now it is certain that the consensus is not yet reached within the international community and the discussion of these issues will continue for some time the new recommendations should be seen as a consolidation of recommendations from 1990 to give a single unified set that can be simply and coherently expressed. The paper presents essential issues of the outcome of the Commission discussions and improvement of the current system of radiation protection.(author)

Plasma antennas: dynamically configurable antennas for communications

International Nuclear Information System (INIS)

Borg, G.; Harris, J.

1999-01-01

In recent years, the rapid growth in both communications and radar systems has led to a concomitant growth in the possible applications and requirements of antennas. These new requirements include compactness and conformality, rapid reconfigurability for directionality and frequency agility. For military applications, antennas should also allow low absolute or out-of-band radar cross-section and facilitate low probability of intercept communications. Investigations have recently begun worldwide on the use of ionised gases or plasmas as the conducting medium in antennas that could satisfy these requirements. Such plasma antennas may even offer a viable alternative to metal in existing applications when overall technical requirements are considered. A recent patent for ground penetrating radar claims the invention of a plasma antenna for the transmission of pulses shorter than 100 ns in which it is claimed that current ringing is avoided and signal processing simplified compared with a metal antenna. A recent US ONR tender has been issued for the design and construction of a compact and rapidly reconfigurable antenna for dynamic signal reception over the frequency range 1 - 45 GHz based on plasma antennas. Recent basic physics experiments at ANU have demonstrated that plasma antennas can attain adequate efficiency, predictable radiation patterns and low base-band noise for HF and VHF communications. In this paper we describe the theory of the low frequency plasma antenna and present a few experimental results

Analysis of the criteria used by the international commission on radiological protection (ICRP) to justify the setting of numerical reference values. Report No. 277

International Nuclear Information System (INIS)

Schieber, C.; Schneider, T.; Lochard, J.; Crouail, P.

2005-05-01

Following its Publication 60, ICRP has proposed nine reports specifying quantified values for dose constraints, action levels, etc. Some 25 values have been identified in all these publications. Since a few years, ICRP is preparing new recommendations in order to provide 'a more coherent and comprehensible system'. The objective of ICRP is to propose to select among the existing quantified values, a few values that could encompass all the other ones. These values are not intended to replace the currently recommended values which remain valid. In this perspective, IRSN has asked CEPN to make a review of all the values introduced in the ICRP publications in order to obtain a broad view of the rationalities proposed by ICRP in the determination of these values. The following Publications of ICRP have been reviewed: - ICRP 60 - 1990 - 1990 Recommendations of ICRP, - ICRP 62 - 1992 - Radiological protection in biomedical research, - ICRP 63 - 1992 - Principles for intervention for protection of the public in a radiological emergency, - ICRP 64 - 1993 - Protection from potential exposure: a conceptual framework, - ICRP 65 - 1993 - Protection against radon-222 at home and at work, - ICRP 68 - 1994 - Dose coefficients for intakes of radionuclides by workers, - ICRP 75 - 1997 - General principles for the radiation protection of workers, - ICRP 77 - 1997 - Radiological protection policy for the disposal of radioactive waste, - ICRP 81 - 2000 - Radiation protection recommendations as applied to the disposal of long-lived solid radioactive waste, - ICRP 82 - 2000 - Protection of the public in situations of prolonged radiation exposure. The different quantitative values found in these publications are presented in this report, grouped by type of value: individual dose limits, 'maximum' individual dose, dose constraints, exemption, action and intervention levels. The rationalities proposed by ICRP for setting these values are presented, mainly based on the quotation of ICRP

Implementation of the 1990 recommendations of the ICRP

International Nuclear Information System (INIS)

Hock, R.

1994-01-01

Detailed investigations have been made of the consequences of ICRP Publication 60 for nuclear power plants. A methodology has not yet been defined for handling the aspect of design against accidents within the framework of ICRP 60. Other new requirements, i.e. new individual limits and the application of higher risk factors, may pose minor problems for plants of older design. In plants of recent collective doses for plant personnel and for the public are already so low that the increase in risk factors will not require additional protection measures. The new limit for the individual dose accumulated during five calendar years may require additional surveillance of a few persons in plants of older design. Intakes of radionuclides are a minor contributor to dose, even at these low levels of exposure. Uncertainties in the determination of a committed dose rather than the actual dose can therefore be tolerated. (Author)

Recommendations of ICRP for radiation protection in 2005

International Nuclear Information System (INIS)

Holm, L. E.

2004-01-01

The present recommendations of the International Commission on Radiological Protection (ICRP) were published in 1991, and since then, the ICRP has provided additional recommendations. The system of protection has become increasingly co plex with time, and the Commission has decided to adopt a new set of recommendations in 2005- These should be seen as a consolidation of earlier recommendations. The new recommendations will recognize where the responsibility for justifying the introduction of a new practice lies, maintain the existing dose limits for individuals, develop the concept of dose constraints, require optimisation of protection from any source to ensure that exposures are as law as reasonably achievable, include of a policy for protection of non-human species, and clarify the dramatics quantities. The Commission intends to adopt the new recommendations in 2005, and this will be 15 years after the current recommendations were adopted. (Author) 13 refs

Radiologic protection in pediatric radiology: ICRP recommendations

International Nuclear Information System (INIS)

Sanchez, Ramon; Khong, Pek-Lan; Ringertz, Hans

2013-01-01

ICRP has provided an updated overview of radiation protection principles in pediatric radiology. The authors recommend that staff, radiologists, medical physicists and vendors involved in pediatric radiology read this document. For conventional radiography, the report gives advice on patient positioning, immobilization, shielding and appropriate exposure conditions. It describes extensively the use of pulsed fluoroscopy, the importance of limiting fluoroscopy time, and how shielding and geometry must be used to avoid unnecessary radiation to the patient and operator. Furthermore, the use of fluoroscopy in interventional procedures with emphasis on dose reduction to patients and staff is discussed in light of the increasing frequency, complexity and length ofthe procedures. CT is the main reason that medical imaging in several developed countries is the highest annual per capita effective radiation dose from man-made sources. The ICRP report gives extensive descriptions of how CT protocols can be optimized to minimize radiation exposure in pediatric patients. The importance of balancing image quality with acceptable noise in pediatric imaging and the controversies regarding the use of protective shielding in CT are also discussed.

Overview of the ICRP/ICRU adult reference computational phantoms and dose conversion coefficients for external idealised exposures

International Nuclear Information System (INIS)

Endo, Akira; Petoussi-Henss, Nina; Zankl, Maria; Schlattl, Helmut; Bolch, Wesley E.; Eckerman, Keith F.; Hertel, Nolan E.; Hunt, John G.; Pelliccioni, Maurizio; Menzel, Hans-Georg

2014-01-01

This paper reviews the ICRP Publications 110 and 116 describing the reference computational phantoms and dose conversion coefficients for external exposures. The International Commission on Radiological Protection (ICRP) in its 2007 Recommendations made several revisions to the methods of calculation of the protection quantities. In order to implement these recommendations, the DOCAL task group of the ICRP developed computational phantoms representing the reference adult male and female and then calculated a set of dose conversion coefficients for various types of idealised external exposures. This paper focuses on the dose conversion coefficients for neutrons and investigates their relationship with the conversion coefficients of the protection and operational quantities of ICRP Publication 74. Contributing factors to the differences between these sets of conversion coefficients are discussed in terms of the changes in phantoms employed and the radiation and tissue weighting factors. This paper briefly reviews the reference computational phantoms and dose conversion coefficients for external exposures that were published jointly by ICRP and ICRU. Both these publications appeared as a consequence of the ICRP 2007 Recommendations; to implement these recommendations, the ICRP has developed reference computational phantoms representing the adult male and female. These phantoms are used to calculate reference dose conversion coefficients for external and internal sources. Using the reference phantoms and methodology consistent with the 2007 Recommendations, dose conversion coefficients for both effective doses and organ-absorbed doses for various types of idealised external exposures have been calculated. These data sets supersede the existing ICRP/ICRU data sets and expand the particle types and energy ranges. For neutrons, the new effective dose conversion coefficients become smaller compared with those in ICRP74, for energies below hundreds of keV. This is mainly

Implementation of the ICRP 66 respiratory tract model: example of occupational exposure to uranium oxides formed in a new laser enrichment process

International Nuclear Information System (INIS)

Ansoborlo, E.; Henge-Napoli, M.H.; Hodgson, A.; Stradling, G.N.; Birchall, A.

1996-01-01

A new uranium enrichment facility using laser isotopic separation generates aerosols consisting of U metal + UO 2 : with traces of UPON. Results of lung absorption to blood showed that the U metal + UO 2 transportability was appreciably greater than for other industrial forms of UO 2 . Taking into account the new ICRP human respiratory tract model, the data were used as a basis for assessing the dose coefficient, for the dust sampled at the workplace. (author)

Directional borehole antenna - Theory

International Nuclear Information System (INIS)

Falk, L.

1992-02-01

A directional antenna has been developed for the borehole radar constructed during phase 2 of the Stripa project. The new antenna can determine the azimuth of a strong reflector with an accuracy of about 3 degrees as confirmed during experiments in Stripa, although the ratio of borehole diameter to wavelength is small, about 0.03. The antenna synthesizes the effect of a loop antenna rotating in the borehole from four signals measured in turn by a stationary antenna. These signals are also used to calculate an electric dipole signal and a check sum which is used to examine the function of the system. The theory of directional antennas is reviewed and used to design an antenna consisting of four parallel wires. The radiation pattern of this antenna is calculated using transmission line theory with due regard to polarization, which is of fundamental importance for the analysis of directional data. In particular the multipole expansion of the field is calculated to describe the antenna radiation pattern. Various sources of error, e.g. the effect of the borehole, are discussed and the methods of calibrating the antenna are reviewed. The ambiguity inherent in a loop antenna can be removed by taking the phase of the signal into account. Typical reflectors in rock, e.g. fracture zones an tunnels, may be modelled as simple geometrical structures. The corresponding analysis is described and exemplified on measurements from Stripa. Radar data is nowadays usually analyzed directly on the computer screen using the program RADINTER developed within the Stripa project. An algorithm for automatic estimation of the parameters of a reflector have been tested with some success. The relation between measured radar data and external coordinates as determined by rotational indicators is finally expressed in terms of Euler angles. (au)

Integrated reconfigurable multiple-input–multiple-output antenna system with an ultra-wideband sensing antenna for cognitive radio platforms

KAUST Repository

Hussain, Rifaqat; Sharawi, Mohammad S.

2015-01-01

. The developed model can be used as a complete antenna platform for cognitive radio applications. The antenna system is developed on a single substrate area of dimensions 65 × 120 mm². The proposed sensing antenna is used to cover a wide range

Benchmark simulations of ICRF antenna coupling

International Nuclear Information System (INIS)

Louche, F.; Lamalle, P. U.; Messiaen, A. M.; Compernolle, B. van; Milanesio, D.; Maggiora, R.

2007-01-01

The paper reports on ongoing benchmark numerical simulations of antenna input impedance parameters in the ion cyclotron range of frequencies with different coupling codes: CST Microwave Studio, TOPICA and ANTITER 2. In particular we study the validity of the approximation of a magnetized plasma slab by a dielectric medium of suitably chosen permittivity. Different antenna models are considered: a single-strap antenna, a 4-strap antenna and the 24-strap ITER antenna array. Whilst the diagonal impedances are mostly in good agreement, some differences between the mutual terms predicted by Microwave Studio and TOPICA have yet to be resolved

Integrated reconfigurable multiple-input–multiple-output antenna system with an ultra-wideband sensing antenna for cognitive radio platforms

KAUST Repository

Hussain, Rifaqat

2015-06-18

© The Institution of Engineering and Technology 2015. A compact, novel multi-mode, multi-band frequency reconfigurable multiple-input-multiple-output (MIMO) antenna system, integrated with ultra-wideband (UWB) sensing antenna, is presented. The developed model can be used as a complete antenna platform for cognitive radio applications. The antenna system is developed on a single substrate area of dimensions 65 × 120 mm². The proposed sensing antenna is used to cover a wide range of frequency bands from 710 to 3600 MHz. The frequency reconfigurable dual-element MIMO antenna is integrated with P-type, intrinsic, N-type (PIN) diodes for frequency agility. Different modes of selection are used for the MIMO antenna system reconfigurability to support different wireless system standards. The proposed MIMO antenna configuration is used to cover various frequency bands from 755 to 3450 MHz. The complete system comprising the multi-band reconfigurable MIMO antennas and UWB sensing antenna for cognitive radio applications is proposed with a compact form factor.

Protection of the Environment: Current ICRP Work and EC-Funded Research

International Nuclear Information System (INIS)

Larsson, C.M.; Holm, L.E.

2003-01-01

The requirement for assessments of the environmental effects of radiation, i.e. effects on non-human biota, is increasing due to growing public concern for environmental protection issues and integration of environmental impact assessments into the regulatory process. Thus, there is a strong need to establish a framework for the assessment of environmental impact of ionising radiation, as well as a system for protection of the environment from ionising radiation. These ambitions are reflected in a number of international efforts and various 'systems' have been proposed or are under development. This paper considers the current discussions on environmental protection within the International Commission on Radiological Protection (ICRP), as part of the Commission's ongoing revision of its recommendations as laid out in Publication 60. Furthermore, the paper reviews work within the EC-funded FASSET (Framework for ASSessment of Environmental impacT) project. The concepts developed both by ICRP and FASSET are similar, and the FASSET approach and results may illustrate how forthcoming ICRP recommendations could be turned into practical application. (orig.)

Sequential modelling of ICRF wave near RF fields and asymptotic RF sheaths description for AUG ICRF antennas

Directory of Open Access Journals (Sweden)

Jacquot Jonathan

2017-01-01

Full Text Available A sequence of simulations is performed with RAPLICASOL and SSWICH to compare two AUG ICRF antennas. RAPLICASOL outputs have been used as input to SSWICH-SW for the AUG ICRF antennas. Using parallel electric field maps and the scattering matrix produced by RAPLICASOL, SSWICH-SW, reduced to its asymptotic part, is able to produce a 2D radial/poloidal map of the DC plasma potential accounting for the antenna input settings (total power, power balance, phasing. Two models of antennas are compared: 2-strap antenna vs 3-strap antenna. The 2D DC potential structures are correlated to structures of the parallel electric field map for different phasing and power balance. The overall DC plasma potential on the 3-strap antenna is lower due to better global RF currents compensation. Spatial proximity between regions of high RF electric field and regions where high DC plasma potentials are observed is an important factor for sheath rectification.

On equivalent radius of curvature for PWL geometrical modeling a loop antenna

CSIR Research Space (South Africa)

Lysko, AA

2012-11-01

Full Text Available A circular loop antenna is often numerically modeled using a regular polygon. This approach is simple and robust, yet it alters the circumference of the loop and may thus shift the resonance frequency in the numerical model. This letter introduces a...

Wireless interrogation of passive antenna sensors

International Nuclear Information System (INIS)

Deshmukh, S; Huang, H

2010-01-01

Recently, we discovered that the resonant frequency of a microstrip patch antenna is sensitive to mechanical strains or crack presence in the ground plane. Based on this principle, antenna sensors have been demonstrated to measure strain and detect crack in metallic structures. This paper presents a wireless method to remotely interrogate a dual-frequency antenna sensor. An interrogation horn antenna was used to irradiate the antenna sensor with a linear chirp microwave signal. By implementing a light-activated switch at the sensor node and performing signal processing of the backscattered signals, the resonant frequencies of the antenna sensor along both polarizations can be measured remotely. Since the antenna sensor does not need a local power source and can be interrogated wirelessly, electric wiring can be eliminated. The sensor implementation, the signal processing and the experimental setup that validate the remote interrogation of the antenna sensor are presented. A power budget model has also been established to estimate the maximum interrogation range

Circularly polarized antennas

CERN Document Server

Gao, Steven; Zhu, Fuguo

2013-01-01

This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Adva

Compact Dual-Band Zeroth-Order Resonance Antenna

International Nuclear Information System (INIS)

Xu He-Xiu; Wang Guang-Ming; Gong Jian-Qiang

2012-01-01

A novel microstrip zeroth-order resonator (ZOR) antenna and its equivalent circuit model are exploited with two zeroth-order resonances. It is constructed based on a resonant-type composite right/left handed transmission line (CRLH TL) using a Wunderlich-shaped extended complementary single split ring resonator pair (W-ECSSRRP) and a series capacitive gap. The gap either can be utilized for double negative (DNG) ZOR antenna or be removed to engineer a simplified elision-negative ZOR (ENG) antenna. For verification, a DNG ZOR antenna sample is fabricated and measured. Numerical and experimental results agree well with each other, indicating that the omnidirectional radiations occur at two frequency bands which are accounted for by two shunt branches in the circuit model. The size of the antenna is 49% more compact than its previous counterpart. The superiority of W-ECSSRRP over CSSRRP lies in the lower fundamental resonance of the antenna by 38.2% and the introduction of a higher zeroth-order resonance. (fundamental areas of phenomenology(including applications))

ICRP path forward to the next recommendations. WNA (World Nuclear Association) preliminary views on the ICRP (International Commission on Radiological Protection) proposed profound changes to the current RP system and on continuing to build an international consensus towards an improved proposal

International Nuclear Information System (INIS)

Saint-Pierre, S.

2006-01-01

For several years, international policy on radiological protection has been under discussion with a view to a significant revision (recently delayed until 2006-2007). The focal point of this discussion has been an evolving draft proposal of the International Commission on Radiological Protection (ICRP). The ICRP's seminal role in its field is well-known. Generally, ICRP recommendations are translated into the international and national standards that govern industry operations worldwide. (author)

ICRP 's view on protection of non-human species from ionising radiation

International Nuclear Information System (INIS)

Holm, L.E.

2003-01-01

The International Commission on Radiological Protection (ICRP) is currently reviewing its existing recommendations for radiological protection. Up till now, it has not published any recommendations as to how assessment or management of radiation effects in non-human organisms should be carried out. The Commission set up a Task Group in the year 2000 to address this issue, and recently adopted the Task Group's report. The report addresses the role that ICRP could play in this important and developing area, building on the approach that has been developed for human protection. ICRP will develop a small set of Reference Fauna and Flora, plus their relevant databases to serve as a basis for the more fundamental understanding and interpretation of the relationships between exposure and dose, and between dose and certain categories of effect. The concept of Reference Fauna and Flora is similar to that of Reference Man used for human radiological protection, in that it is intended to act as a basis for calculations and decision-making. The decision by the Commission to develop a framework for the assessment of radiation effects in non-human species has not been driven by any particular concern over environmental radiation hazards. It has rather been developed to fill a conceptual gap in radiological protection, and to clarify how ICRP can contribute to the attainment of society's goals of environmental protection by developing a protection policy based on scientific and ethical-philosophical principles. (author)

Dosimetric methodology of the ICRP

International Nuclear Information System (INIS)

Eckerman, K.F.

1994-01-01

Establishment of guidance for the protection of workers and members of the public from radiation exposures necessitates estimation of the radiation dose to tissues of the body at risk. The dosimetric methodology formulated by the International Commission on Radiological Protection (ICRP) is intended to be responsive to this need. While developed for radiation protection, elements of the methodology are often applied in addressing other radiation issues; e.g., risk assessment. This chapter provides an overview of the methodology, discusses its recent extension to age-dependent considerations, and illustrates specific aspects of the methodology through a number of numerical examples

Implications of recent ICRP recommendations for risk assessments for radioactive waste disposal and cleanup

International Nuclear Information System (INIS)

Devgun, J.S.

1992-01-01

The International Commission on Radiological Protection (ICRP) adopted a new set of recommendations in November 1990 which were issued at ICRP Publication No. 60 in March 1991. These recommendations incorporate new radiobiological information and outline a comprehensive system of radiological protection. This paper evaluates the implications of these new recommendations vis a vis risk assessments for radioactive waste disposal and remediation of radioactively contaminated sites

Thought about ICRP TG84 report. What beyond it

International Nuclear Information System (INIS)

Niwa, Ohtsura

2013-01-01

Explained was the ICRP TG84 Report (Report of ICRP Task Group 84 on Initial Lessons Learned from the Nuclear Power Plant Accident in Japan vis-a-vis the ICRP System of Radiological Protection: Issues Identified from the NPP Accident in Japan and Recommendations to Improve the System of Radiation Protection; presented in October, 2012), together with author's thought about it. The Report contained 18 items and their related proposals: Inferring radiation risks (and the misunderstanding of nominal risk coefficients), Attributing radiation effects from low dose exposures, Quantifying radiation exposure, Assessing the importance of internal exposures, Managing emergency crisis, Protecting rescuers and volunteers, Responding with medical aid, Justifying necessary but disruptive protective actions, Transiting from an emergency to an existing situation, Rehabilitating evacuated areas, Categorizing public exposures due to an accident, Restricting individual doses of members of the public, Caring for infants and children, Considering pregnant women and their foetuses and embryos, Monitoring public protection, Dealing with 'contamination' of territories, rubble and residues, and consumer products, Recognizing the importance of psychological consequences, and Fostering the sharing of information. The Report also contained 11 Recommendations of actions for the Commission to take. The author had been installed as the Chair of Radiation Council in February, 2011, just before the Accident in March, and had had to concern the definition of various post-Accident dose limits in Japan, having had often faced the inefficiency of measures. He thought the ICRP protecting system was difficult to understand due to 2 reasons: one was that the system had been written aiming at experts of radiological protection and the other, that the system had been composed not only from science but also from an incorporated standard of social values, which resulted in inconsiderateness to the general

Uses and limitations of dosimetric data in ICRP 30

International Nuclear Information System (INIS)

Eckerman, K.F.

1985-01-01

The ICRP recommendations of Publications 26 and 30 provide a well founded, logical approach to radiation protection. These recommendations lend themselves to scientific scrutiny and evaluation much more than the earlier recommendations. While there are many issues which national authorities may find necessary to address as they develop their national radiation protection guidance, the long awaited revision of the ICRP recommendations provides the technical bases upon which such guidance can be developed. The acceptance of the new recommendations by national authorities and the radiation protection community appears to be related to the lack of substantial departure in the numerical value of the secondry limits from the previous limits. This reflects an apparent concensus that the earlier recommendations provided an adequate level of protection. It thus appears reasonable to suggest that a similar level of protection is offered by the new recommendations. 24 refs., 2 figs., 7 tabs

Non-stochastic effects: compatibility with present ICRP recommendations

International Nuclear Information System (INIS)

Field, S.B.; Upton, A.C.; New York Univ., NY

1985-01-01

The present recommendations of the ICRP (International Commission on Radiological Protection) are almost entirely based on 'stochastic effects' of ionizing radiation, i.e. cancer induction and heritable effects. In a recent report the compatibility of present recommendations with non-stochastic effects has been considered. The present paper is a summary of these findings. (author)

Analysis of the new ICRP recommendations from the point of view of environmental impact

International Nuclear Information System (INIS)

Gonzalez, A.J.

1978-01-01

The paper analyses the implications of the new ICRP recommendations referring optimization and justification as they apply to the nuclear power industry, in particular referring to its environmental impact. It also discusses the possible effects of applying this requirements on regional nuclear power programmes. The possibility of extrapolating the ICRP recommendations for use as a basis for nuclear safety aspects of nuclear power reactors is also analyzed. (author)

The work of Committee 2 of ICRP on internal dosimetry

International Nuclear Information System (INIS)

Stather, J.W.

2007-01-01

Following publication of new recommendations by ICRP, a series of publications on Occupational Intakes of Radionuclides (OIR) will give both dose coefficients for intakes of radionuclides and data for the interpretation of bioassay information. Account will be taken of revised tissue weighting factors given in the new recommendations and a number of additional developments. These include new human phantoms based upon medical imaging data for calculating doses to body tissues and the new Human Alimentary Tract Model. In addition, parameter values for the Human Respiratory Tract Model are being reviewed, radionuclide decay data are being updated and systemic models for a number of elements revised to take account of more recent data and to provide models that are appropriate for both dosimetry and for bioassay interpretation. The OIR series of publications will be accompanied by a supporting Guidance Document that will give advice on the interpretation of bioassay data. (author)

Overview of the ICRP/ICRU adult reference computational phantoms and dose conversion coefficients for external idealised exposures

CERN Document Server

Endo, A; Zankl, M; Bolch, W E; Eckerman, K F; Hertel, N E; Hunt, J G; Pelliccioni, M; Schlattl, H; Menzel, H-G

2014-01-01

This paper reviews the ICRP Publications 110 and 116 describing the reference computational phantoms and dose conversion coefficients for external exposures. The International Commission on Radiological Protection (ICRP) in its 2007 Recommendations made several revisions to the methods of calculation of the protection quantities. In order to implement these recommendations, the DOCAL task group of the ICRP developed computational phantoms representing the reference adult male and female and then calculated a set of dose conversion coefficients for various types of idealised external exposures. This paper focuses on the dose conversion coefficients for neutrons and investigates their relationship with the conversion coefficients of the protection and operational quantities of ICRP Publication 74. Contributing factors to the differences between these sets of conversion coefficients are discussed in terms of the changes in phantoms employed and the radiation and tissue weighting factors.

A framework for assessing the impact of ionising radiation on non-human species ICRP Publication 91

International Nuclear Information System (INIS)

Valentin, J.

2003-01-01

In its 1990 Recommendations, the ICRP indicated that it believed that the standards of environmental control needed to protect man to the degree currently thought desirable would ensure that other species are not put at risk. The ICRP considers that its system of radiological protection has provided a fairly good indirect protection of the human habitat. However, no internationally agreed criteria or policies explicitly address protection of the environment from ionising radiation, and it is difficult to determine or demonstrate whether or not the environment is adequately protected from potential impacts of radiation under different circumstances. The present report suggests a framework, based on scientific and ethical-philosophical principles, by which a policy for the protection of non-human species could be achieved. The primary purpose of developing such a framework is to fill a conceptual gap in radiological protection; it does not reflect any particular concern over environmental radiation hazards. The proposed framework is designed to harmonise with the ICRP's approach to the protection of human beings, but does not intend to set regulatory standards. Instead, the proposed framework is intended to be a practical tool to provide high-level advice and guidance for regulators and operators. An agreed set of quantities and units, a set of reference dose models, reference dose-per-unit-intake (or unit exposure), and reference fauna and flora are required to serve as a basis for the more fundamental understanding and interpretation of the relationships between exposure and dose and between dose and certain categories of effect, for a few, clearly defined types of animals and plants. As a first step, a small set of reference fauna and flora with supporting databases will be developed by the ICRP. Others can then develop more area- and situation-specific approaches to assess and manage risks to non-human species

On revision of definition of doses for radiation protection in ICRP 1990 recommendations

International Nuclear Information System (INIS)

Yoshizawa, Michio

1995-01-01

The recommendation of ICRP is to give the guideline to the organizations and experts concerned to radiation protection including regulatory authorities on the basic rule which becomes the basis of proper radiation protection, and the radiation protection in respective countries has been carried out, respecting this ICRP recommendation. In 1990, ICRP revised this basic recommendation, and published as Publication 60. In this 1990 recommendation, as the matters that give impact to the dose evaluation of external exposure, the introduction of the new concept of dose, namely radiation weighting factor and equivalent dose, the revision of radiation quality factor and so on are enumerated. As to the 1990 recommendation, absorbed dose and organ dose, radiation weighting factor, equivalent dose, effective dose, quality factor-LET relation, the summation with the former quantities and the operational quantity of ICRU are described. The reason why radiation weighting factor and equivalent dose were introduced are discussed, including the inference of the author. (K.I.)

Impact on Dose Coefficients Calculated with ICRP Adult Mesh-type Reference Computational Phantoms

Energy Technology Data Exchange (ETDEWEB)

Yeom, Yeon Soo; Nguyen, Thang Tat; Choi, Chan Soo; Lee, Han Jin; Han, Hae Gin; Han, Min Cheol; Shin, Bang Ho; Kim, Chan Hyeong [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

2017-04-15

In 2016, the International Commission on Radiological Protection (ICRP) formulated a new Task Group (TG) (i.e., TG 103) within Committee 2. The ultimate aim of the TG 103 is to develop the mesh-type reference computational phantoms (MRCPs) that can address dosimetric limitations of the currently used voxel-type reference computational phantoms (VRCPs) due to their limited voxel resolutions. The objective of the present study is to investigate dosimetric impact of the adult MRCPs by comparing dose coefficients (DCs) calculated with the MRCPs for some external and internal exposure cases and the reference DCs in ICRP Publications 116 and 133 that were produced with the adult VRCPs. In the present study, the DCs calculated with the adult MRCPs for some exposure cases were compared with the values in ICRP Publications 116 and 133. This comparison shows that in general the MRCPs provide very similar DCs for uncharged particles, but for charged particles provide significantly different DCs due to the improvement of the MRCPs.

Modelling of DC electric fields induced by RF sheath in front of ICRF antenna

International Nuclear Information System (INIS)

Faudot, E.; Heuraux, S.; Colas, L.

2003-01-01

Reducing the ICRF (ion cyclotron range frequency) antenna-plasma interaction is one of the key points for reaching very long tokamak discharges. One problem which limits such discharges, is the appearance of hot spots on the surface of the antenna: Radio Frequency (RF) sheaths modify the properties of the edge plasma by rectifying the RF potential along open magnetic field lines and can induce hot spots. This paper investigates the corrections to sheath potentials introduced by the interactions between adjacent flux tubes. Our theoretical study started from an oscillating double Langmuir probe model, in which a transverse influx of current was included. This model was confronted with 1D PIC simulations along a magnetic field line, and demonstrated that current exchanges can decrease mean potentials. A 2D electrostatic fluid code was then developed, which couples adjacent flux tubes in a poloidal cross section with collisional conductivity or polarization currents. It showed that transverse currents are able to smooth structures smaller than a characteristic size in the sheath potential maps (results for Tore Supra). These computed rectified potentials can be used to obtain the DC electric fields in front of the antenna. And then, it gives an estimate of the particle drift and the energy flux on the antenna structure, which can explain hot spots. (author)

Analysis of a Waveguide-Fed Metasurface Antenna

Science.gov (United States)

Smith, David R.; Yurduseven, Okan; Mancera, Laura Pulido; Bowen, Patrick; Kundtz, Nathan B.

2017-11-01

The metasurface concept has emerged as an advantageous reconfigurable antenna architecture for beam forming and wave-front shaping, with applications that include satellite and terrestrial communications, radar, imaging, and wireless power transfer. The metasurface antenna consists of an array of metamaterial elements distributed over an electrically large structure, each subwavelength in dimension and with subwavelength separation between elements. In the antenna configuration we consider, the metasurface is excited by the fields from an attached waveguide. Each metamaterial element can be modeled as a polarizable dipole that couples the waveguide mode to radiation modes. Distinct from the phased array and electronically-scanned-antenna architectures, a dynamic metasurface antenna does not require active phase shifters and amplifiers but rather achieves reconfigurability by shifting the resonance frequency of each individual metamaterial element. We derive the basic properties of a one-dimensional waveguide-fed metasurface antenna in the approximation in which the metamaterial elements do not perturb the waveguide mode and are noninteracting. We derive analytical approximations for the array factors of the one-dimensional antenna, including the effective polarizabilities needed for amplitude-only, phase-only, and binary constraints. Using full-wave numerical simulations, we confirm the analysis, modeling waveguides with slots or complementary metamaterial elements patterned into one of the surfaces.

ICRP recommendations and the safe disposal of radioactive waste

International Nuclear Information System (INIS)

Webb, G.A.M.; Barraclough, I.M.

1991-01-01

There are some special difficulties in setting up and applying radiological protection principle to the disposal of solid radioactive wastes. These were recognized by the International Commission on Radiological Protection (ICRP). One difficulty is the uncertain or probabilistic nature of some of the events or processes that could occur and affect the integrity of a waste repository. The other feature of solid waste disposal that causes difficulty is the length of time period of concern. The practical problem is the difficulties in predicting future conditions and in making the useful estimate of long term radiation impact with sufficient confidence. In this paper, the proposals made by the ICRP to deal with the above difficulties are briefly reviewed. Some suggestions are made as to how the criteria might be clarified, and the necessary calculation made to match the criteria. The reappraisal of the criteria for assessing the radiological safety of waste repositories is needed. (K.I.)

Discussion on Implementation of ICRP Recommendations Concerning Reference Levels and Optimisation

International Nuclear Information System (INIS)

2013-02-01

International Commission on Radiological Protection (ICRP) Publication 103, 'The 2007 Recommendations of the International Commission on Radiological Protection', issued in 2007, defines emergency exposure situations as unexpected situations that may require the implementation of urgent protective actions and perhaps longer term protective actions. The ICRP continues to recommend optimisation and the use of reference levels to ensure an adequate degree of protection in regard to exposure to ionising radiation in emergency exposure situations. Reference levels represent the level of dose or risk above which it is judged to be inappropriate to plan to allow exposures to occur and for which protective actions should therefore be planned and optimised. National authorities are responsible for establishing reference levels. The Expert Group on the Implementation of New International Recommendations for Emergency Exposure Situations (EGIRES) performed a survey to analyse the established processes for optimisation of the protection strategy for emergency exposure situations and for practical implementation of the reference level concept in several member states of the Nuclear Energy Agency (NEA). The EGIRES collected information on several national optimisation strategy definitions, on optimisation of protection for different protective actions, and also on optimisation of urgent protective actions. In addition, national criteria for setting reference levels, their use, and relevant processes, including specific triggers and dosimetric quantifies in setting reference levels, are focus points that the EGIRES also evaluated. The analysis of national responses to this 2011 survey shows many differences in the interpretation and application of the established processes and suggests that most countries are still in the early stages of implementing these processes. Since 2011, national authorities have continued their study of the ICRP recommendations to incorporate them into

Equipment: Antenna systems

Science.gov (United States)

Petrie, L. E.

1986-03-01

Some antenna fundamentals as well as definitions of the principal terms used in antenna engineering are described. Methods are presented for determining the desired antenna radiation patterns for HF communication circuit or service area. Sources for obtaining or computing radiation pattern information are outlined. Comparisons are presented between the measured and computed radiation patterns. The effect of the properties of the ground on the antenna gain and the pattern are illustrated for several types of antennas. Numerous examples are given of the radiation patterns for typical antennas used on short, intermediate and long distance circuits for both mobile and fixed service operations. The application of adaptive antenna arrays and active antennas in modern HF communication systems are briefly reviewed.

The direction of ICRP - new recommendations

International Nuclear Information System (INIS)

Clarke, R.H.

2004-01-01

ICRP has been stimulating discussion, during the past three years, on the best way of expressing protection philosophy for the next publication of its Recommendations, which it hopes will be by 2005. The present recommendations were initiated by Publication 60 in 1990 and have subsequently been complemented by additional publications over the last twelve years. In this paper the totality of those recommendations is summarised and used to indicate a way forward to produce a simplified and more coherent statement of protection philosophy for the start of the 21. century. (author)

Geodetic antenna calibration test in the Antarctic environment

Science.gov (United States)

Grejner-Brzezinska, A.; Vazquez, E.; Hothem, L.

2006-01-01

TransAntarctic Mountain DEFormation (TAMDEF) Monitoring Network is the NSF-sponsored OSU and USGS project, aimed at measuring crustal motion in the Transantarctic Mountains of Victoria Land using GPS carrier phase measurements. Station monumentation, antenna mounts, antenna types, and data processing strategies were optimized to achieve mm-level estimates for the rates of motion. These data contributes also to regional Antarctic frame definition. Significant amount of data collected over several years allow the investigation of unique aspects of GPS geodesy in Antarctica, to determine how the error spectrum compares to the mid-latitude regions, and to identify the optimum measurement and data processing schemes for Antarctic conditions, in order to test the predicted rates of motion (mm-level w.r.t. time). The data collection for the TAMDEF project was initiated in 1996. The primary antenna used has been the Ashtech L1/L2 Dorne Margolin (D/M) choke ring. A few occupations involved the use of a Trimble D/M choke ring. The data were processed using the antenna calibration data available from the National Geodetic Survey (NGS). The recent developments in new antenna designs that are lighter in weight and lower in cost are being considered as a possible alternative to the bulkier and more expensive D/M choke ring design. In November 2003, in situ testing of three alternative models of L1/L2 antennas was conducted at a site located in the vicinity of McMurdo Station, Antarctica (S77.87, E166.56). The antenna models used in this test were: Ashtech D/M choke ring, Trimble D/M choke ring, Trimble Zephyr, and the NovAtel GPS-702. Two stations, spaced within 30 meters, were used in the test. Both had the characteristics similar to the stations of the TAMDEF network, i.e., the UNAVCO fixed-height, force-centered level mounts with a constant antenna offset were used, ensuring extreme stability of the antenna/ mount/pin set up. During each of the four 3-day test data collection

ICRP publication 26. Its applicability in a nuclear power programme

International Nuclear Information System (INIS)

Wilson, R.; Donnelly, K.

1980-01-01

Ontario Hydro is a major Canadian provincial utility with more than 5 GW(e) installed nuclear electricity generating capacity and with a planned commitment to an additional 8.5 GW(e), all units being of the CANDU pressurized heavy-water type. The radiation protection programme, in addition to complying with Canadian Federal regulations, has been consistent with the philosophy and intent of ICRP recommendations and is frequently reviewed to ensure compliance with these recommendations, the most recent of which is ICRP-26. The application of the ALARA principle in this power reactor programme is described. A set of general guidelines has been established, the main features of which are: (a) achieving a dose consumption per unit of electricity generated which is low compared with reactors of a similar type; (b) ensuring that stations are operable with the dose equivalent of their labour-dictated manpower; (c) ensuring that the risk to atomic radiation workers is compatible with a corporate fatality rate standard of 8 man-hours worked. Achievement of these guidelines has necessitated implementing a continued dose-management programme. This programme is described generally. The cost applied to justify a dose reduction of 1 man.Sv is given, and a comparison is made with the equivalent life costs this implies and the costs used by safety agencies for other risk-reduction activities. Finally, some practical problems associated with some of the recommendations of ICRP-26 are discussed. (author)

TLM modeling and system identification of optimized antenna structures

Directory of Open Access Journals (Sweden)

N. Fichtner

2008-05-01

Full Text Available The transmission line matrix (TLM method in conjunction with the genetic algorithm (GA is presented for the bandwidth optimization of a low profile patch antenna. The optimization routine is supplemented by a system identification (SI procedure. By the SI the model parameters of the structure are estimated which is used for a reduction of the total TLM simulation time. The SI utilizes a new stability criterion of the physical poles for the parameter extraction.

A component of the Indian Climate Research Programme (ICRP)

Indian Academy of Sciences (India)

The Indian Climate Research Programme (ICRP) focuses on the study of climate variability and its impact on agriculture. To address the role of the Bay of Bengal in monsoon variability, a process study was organised during July-August 1999, deploying research ships, buoys, INSAT, coastal radar and conventional ...

Implications of ICRP recommendations on the management of radiation protection of workers

International Nuclear Information System (INIS)

Huyskens, C.J.

1992-01-01

The new ICRP recommendations [1] give a slightly revised definition of occupational exposure. Guidance is given with respect to the exposure at work related no natural radiation sources. Where ICRP recommends a source related definition of occupational exposure, the Basic Safety Standards of the European Communities [3] and consequently legislation in member states depart from an effect related definition of workers. Mutual divergence regarding this identification issue will be discussed in this paper. Operational radiation protection is commonly based on the principles of classification of workers, classification of working conditions and classification of places of work. From the management view point, the rationale for applying classification is to balancing the nature and the scale of control measures, monitoring and surveillance, using resources in the most appropriate way. In previous recommendations [2] ICRP has given criteria for classification, based on the projected level of individual annual dose, relative to the recommended dose limits for occupational exposure. This guidance is now regarded as crude and arbitrary and therefore withdrawn. This paper will address some consequences of the revised recommendations as well as options for implementation in the European Community basic safety standards. (author)

Nondimensional characterization and asymptotic model development for multifunctional structures with application to load-bearing antennas

International Nuclear Information System (INIS)

Santapuri, Sushma; Bechtel, Stephen E

2014-01-01

This paper (i) presents a mathematical approach to formulate leading-order models for complex multifunctional systems with coupled thermomechanical and electromagnetic field interactions, and (ii) demonstrates its applicability to the modeling and analysis of a load-bearing antenna, a multifunctional sensing and transmitting device integrated with a load-bearing structure. Starting from first-principle equations, i.e. the thermomechanical balance laws coupled with Maxwell’s equations, nondimensionalization and perturbation techniques are employed to formulate a leading-order model for the coupled system. Depending on the design of the structure and nature of the excitation, the nondimensional numbers arising in the coupled multifunctional system are quantified, and through a relative ordering of these quantities, the dominant physical effects are extracted. The resulting dominant effects determine the regime of operation of the structure, and in turn dictate the appropriate computational model. This approach is demonstrated through an application to a load-bearing antenna for a prototypical design. The resulting leading-order model is subsequently solved, and the electrical and structural response of the load-bearing antenna is analyzed and compared for different combinations of material properties. The framework introduced in this paper is envisioned to have applications in developing leading-order models for a wide range of complex multifunctional systems and can be utilized for their efficient design. (paper)

Present and future JET ICRF antennae

International Nuclear Information System (INIS)

Kaye, A.; Brown, T.; Bhatnagar, V.; Crawley, P.; Jacquinot, J.; Lobel, R.; Plancoulaine, J.; Rebut, P.H.; Wade, T.; Walker, C.

1994-01-01

Since the initial operation of the JET ICRF system in 1985, up to 22 MW has been coupled to the plasma, many heating scenarios have been demonstrated and the main technological problem of RF-specific impurity production overcome. Many developments of the antennae have taken place over this period, notably the replacement of the water-cooled nickel screens with indirectly cooled beryllium screens, and the forthcoming installation of eight new A2 antennae for operation during the pumped divertor phase of JET. The A2 antennae include enhanced provision for fast wave current drive experiments on JET. This paper describes the beryllium screens, the technological results from operation and subsequent inspection of these screens, the design of the A2 antennae and the results from high power RF testing of a model of the A2 antenna. (orig.)

OPERATION MODES AND CHARACTERISTICS OF PLASMA DIPOLE ANTENNA

Directory of Open Access Journals (Sweden)

Nikolay Nikolaevich Bogachev

2014-02-01

Full Text Available Existence modes of  surface electromagnetic wave on a plasma cylinder, operating modes and characteristics of the plasma antenna were studied in this paper. Solutions of the dispersion equation of surface wave were obtained for a plasma cylinder with finite radius for different plasma density values. Operation modes of the plasma asymmetric dipole antenna with finite length and radius were researched by numerical simulation. The electric field distributions of  the plasma antenna in near antenna field and the radiation pattern were obtained. These characteristics were compared to characteristics of the similar metal antenna. Numerical models verification was carried out by comparing of the counted and measured metal antenna radiation patterns.

Quad-Band U-Slot Antenna for Mobile Applications

Directory of Open Access Journals (Sweden)

R. L. Ruiz

2006-06-01

Full Text Available In this paper, two different planar quad-band antennas are designed, modeled, fabricated and measured. Subsequently, the antennas are redesigned using an electromagnetic band gap substrate (EBG. Those new planar antennas operate in four frequency bands: 900 MHz, 1 800 MHz (both GSM, 1 900 MHz (USA and 2 400 to 2 500 MHz (Bluetooth The antenna has four narrow U-shaped slots etched to the patch. Using software, CST Microwave Studio [1], Zeland IE3D [2], and FEMLAB [3], simulations have been carried out to investigate the antenna's performance and characteristics. The antennas designed have been also built and measured to compare the real results with those obtained from the simulations.

The ICRP 60 and the agency's regulations for the safe transport of radioactive material

International Nuclear Information System (INIS)

Biaggio, A.L.; Novo, R.G.

1993-01-01

The International Commission on Radiological Protection (ICRP) has adopted its new '1990 Recommendations of the International Commission on Radiological Protection' in November 1990, they were published in 1991 as 'ICRP Publication 60.' Two main scenarios are considered by the new ICRP's recommendations: a) Protection in proposed and continuing practices (further subdivided as protection against actual exposures and protection against potential exposures); and b) Protection by intervention. Although intervention means any activity in order to decrease the overall exposure, removing existing sources, modifying pathways or reducing the number of exposed individuals, in relation to the transport of radioactive materials, protection by intervention is related mainly to emergency planning, while protection against actual and potential exposures can be considered as the subject of most of the requirements of the 'Regulations for the Safe Transport of Radioactive Material', of the International Atomic Energy Agency (IAEA). The on-going revision of the IAEA Safety Series No. 9, which is aimed at putting this publication in line with the new ICRP recommendations will, for the first time, provide a convalidated radiological framework for the 1996 revision of the Agency Transport Regulations. However, to adapt to the transport area the radiological principles and criteria will require a significant effort and a carefully evaluation of the overall impact of each change proposed. (J.P.N.)

The recommendations 2007 of the International Commission of Radiological Protection (ICRP)

International Nuclear Information System (INIS)

Sugier, A.; Lecomte, J.F.; Nenot, J.C.

2007-01-01

This article deals with the 2007 Recommendations of the International Commission on Radiological Protection (ICRP), in particular in the situations of emergency exposure, after an accident or to natural radioactivity. (authors)

Proceedings of the 15th nuclear safety research association symposium ICRP's 2005 Recommendations on radiological protection

International Nuclear Information System (INIS)

2003-02-01

This is the document of the Symposium in the title, held in Tokyo, 2003. The document contains the greeting by chairperson (Toshiso Kosako, International Commission of Radiological Protection (ICRP) member, Tokyo University): lecture 1; for the title subject presented as ''ICRP's 2005 Recommendations on Radiological Protection'' with its slides entitled ''The Evolution of the System of Radiological Protection-The Justification for ICRP's 2005 Recommendations'' by L.-E. Holm (ICRP Vice-Chairman, Swedish Radiation Protection Authority): lecture 2; ''Protection of the Environment: from Ethics to Genetics''' with slides, ''Ionising Radiation and the Environment'', by R. J. Pentreath (ICRP member, The University of Reading, the United Kingdom (UK)): respectively followed by discussion with 3 Japanese panelists for each lecture: and chairperson's summary. The chair's greeting is about the rise of interest in environmental radiation protection, its background, and related trends in The Organization for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) Committee on Radiation Protection and Public Health (CRPPH). L-EH's presentation involves sections of the background of the recommendations and protection of the environment, mentioning some of the proposed changes in the Commission's recommendations for its 2005 Recommendations. RJP's presentation involves sections of a philosophical platform, environmental management, relevance to radiation and its effects, points of reference and discussion where the impact of radionuclides and radiation in environment on various biological systems is mentioned in view for future. (R.T.)

Exposure implications for uranium aerosols formed at a new laser enrichment facility: application of the ICRP Respiratory Tract and Systemic Model

Energy Technology Data Exchange (ETDEWEB)

Ansorbolo, E.; Hodgson, A.; Stradling, G.N.; Hodgson, S.; Metivier, H.; Henge-Napoli, M.H.; Jarvis, N.S.; Birchall, A

1998-07-01

A pilot enrichment facility developed in France employs laser technology. The development of this process has resulted in three different types of aerosols identified as variable mixtures of U{sub metal}+ UO{sub 2} and U{sub 3}O{sub 8}. A procedure is described for assessing intakes and doses after inhalation of these dusts using site and material specific data in conjunction with the most recent ICRP biokinetic models. It is concluded that exposure control could be based on either radiotoxicity or chemical toxicity and that chest monitoring and urine assay could be useful, provided that measurements are made soon after a known acute intake. (author)

Dose concepts and the achievability of protection for the disposal of long-lived solid waste according to ICRP

International Nuclear Information System (INIS)

Sugier, A.; Schneider, Th.

2010-01-01

Th. Schneider introduced the subject explaining that the main strength of the ICRP is to set up a unified protection system applicable to all types of exposure situations. In 2007, the ICRP issued ICRP 103 which formally replaces the previous recommendations that were issued in 1991 as ICRP 60. One of the major features of the new recommendations is the evolution from 'the previous process-based protection approach using practices and interventions to a situation-based approach applying the fundamental principles of protection to all controllable exposure situations' in a similar way. In the case of radioactive waste disposal, the long timescale to be dealt with led ICRP to publish the dedicated recommendations ICRP 81 (1999) based on ICRP 60. Th. Schneider presented then a series of issues raised by the radioactive waste management community, relating the recommendations of ICRP 81 to the new orientations provided by ICRP 103. Radiation detriment is a complex construction based on not directly measurable quantities such as equivalent and effective doses. Effective dose is a risk-related quantity and should not be used in assessing health effects on a specific individual. Dose and risk as well as the radiation detriment are still appropriate for long term evaluation even though there are uncertainties associated with the assessment of the dose. It would be a mistake to consider that the ICRP dosimetric quantities and the radiation detriment are not appropriate for long term evaluations, but their meaning must be understood. What is at stake is not to evaluate the level of health of a group of population in 10 6 years from now, but to estimate through a comparison (risk indicator associated with several options of protection at the design level of the repository) the level of protection achieved by a radioactive waste strategy. Current radiological protection criteria are a reasonable basis to assess the disposal strategy. They give a general appreciation of the

Application of the ICRP recommendations to revised secondary radiation protection standards

International Nuclear Information System (INIS)

Kennedy, W.E. Jr.; Corley, J.P.

1988-01-01

In 1977, the International Commission on Radiological Protection (ICRP) issued Publication No. 26 containing its recommendations for major changes in the conceptual basis for radiation protection. The new recommendations consider total risk (to the whole body) instead of controlling (critical-organ) risk. Subsequent publications and explanatory statements most useful for providing clarification of the intent of the new recommendations have not resolved practical problems encountered in attempting to apply them to either occupational or public exposures. Some of the problems that still exist in applying these recommendations for estimating doses to members of the public include the following: allowance for age differences within an exposed population group, definition of 50-y dose versus lifetime (70-y) dose, definition of negligible risk levels for individual and collective doses, and derivation of appropriate concentration guidelines. The United States is in the process of adopting the revised recommendations of the ICRP. In addition to adopting versions of the primary radiation protection standards, both the U.S. Nuclear Regulatory Commission and the U.S. Department of Energy have developed draft secondary standards that are similar to the Derived Air Concentration values given by the ICRP. This paper presents a brief history of the development of these revised secondary standards, discusses their technical bases, provides a comparison of them, and discusses their limitations and potential misapplication

ICRP policy for radioactive waste disposal

International Nuclear Information System (INIS)

Nenot, Jean-Claude

2002-01-01

Jean-Claude Nenot (IPSN, France) gave an overview of recommendations from ICRP during the past 25 years that are relevant to the safety of waste disposal. These recommendations were primarily concerned with public exposure, and suggested that the necessary system of protection should be controlled through the principles of constrained optimisation and prescriptive limits. The principles of justification, optimisation and dose and risk limitation were applicable to waste management. Justification should however be applied to the practice resulting in the generation of waste rather than to waste management per se. As regards optimisation, this should be interpreted in a subtler manner than the simple application of cost-benefit analysis, as an aggregation of very small doses over future world populations would be essentially meaningless. The primary criterion should therefore be the dose to an individual from a relevant critical group, and optimisation should also take account of social and economic factors. The application of dose limits had intrinsic difficulties because of multiple sources, through restrictions determined as a result of monitoring could be envisaged. The approach to dealing with potential future intrusion presented a particular difficulty (as compared to natural processes) because the probability of occurrence could not realistically be determined and therefore a risk-based approach was not recommended. Instead, prospective doses should be assessed against criteria for intervention situations, as proposed in ICRP 82, i.e. action (in terms of a preventative design change, for example) was unlikely to be justifiable at hypothetical and uncertain future dose levels below about 10 mSv/year

Education and training in radiological protection for diagnostic and interventional procedures ICRP 113 in brief

International Nuclear Information System (INIS)

Salama, S.; Gomaa, M. A.; Alshoufi, J.H.

2013-01-01

The international commission on radiological protection (ICRP) is the primary body in protection against ionizing radiation. Among its latest publication is ICRP publication 113 e ducation and training in radiological protection for diagnostic and interventional procedures . This document introduces diagnostic and interventional medical procedures using ionizing radiations in deep details. The document is approved by the commission in October 2010 and translated into Arabic at December 2011. This work is a continuation of the efforts series to translate some of the most important of the radiological protection references into the Arabic; aiming to maximize the benefit. The previous translation include WHO handbook on indoor radon: a public health perspective, issued by world health organization 2009 and Radiation Protection in Medicine, ICRP Publication 105 2007 that translated into Arabic with support of Arab atomic energy authority at 2011.

Analysis of the stress-deformed condition of the disassembly parabolic antenna

Science.gov (United States)

Odinets, M. N.; Kaygorodtseva, N. V.; Krysova, I. V.

2018-01-01

Active development of satellite communications and computer-aided design systems raises the problem of designing parabolic antennas on a new round of development. The aim of the work was to investigate the influence of the design of the mirror of a parabolic antenna on its endurance under wind load. The research task was an automated analysis of the stress-deformed condition of various designs of computer models of a paraboloid mirror (segmented or holistic) at modeling the exploitation conditions. The peculiarity of the research was that the assembly model of the antenna’s mirror was subjected to rigid connections on the contacting surfaces of the segments and only then the finite element grid was generated. The analysis showed the advantage of the design of the demountable antenna, which consists of cyclic segments, in front of the construction of the holistic antenna. Calculation of the stress-deformed condition of the antennas allows us to conclude that dividing the design of the antenna’s mirror on parabolic and cyclic segments increases it strength and rigidity. In the future, this can be used to minimize the mass of antenna and the dimensions of the disassembled antenna. The presented way of modeling a mirror of a parabolic antenna using to the method of the finite-element analysis can be used in the production of antennas.

Modelling of bow-tie microstrip antennas using modified locally conformal FDTD method

NARCIS (Netherlands)

George, J.

2000-01-01

An analysis of bow-tie microstrip antennas is presented based on the use of the modified locally conformal finite-difference time-domain (FDTD) method. This approach enables the number of cells along the antenna length and width to be chosen independently of the antenna central width, which helps to

The computation of ICRP dose coefficients for intakes of radionuclides with PLEIADES: biokinetic aspects.

Science.gov (United States)

Fell, T P

2007-01-01

The ICRP has published dose coefficients for the ingestion or inhalation of radionuclides in a series of reports covering intakes by workers and members of the public including children and pregnant or lactating women. The calculation of these coefficients conveniently divides into two distinct parts--the biokinetic and dosimetric. This paper gives a brief summary of the methods used to solve the biokinetic problem in the generation of dose coefficients on behalf of the ICRP, as implemented in the Health Protection Agency's internal dosimetry code PLEIADES.

The computation of ICRP dose coefficients for intakes of radionuclides with PLEIADES: biokinetic aspects

International Nuclear Information System (INIS)

Fell, T.P.

2007-01-01

The ICRP has published dose coefficients for the ingestion or inhalation of radionuclides in a series of reports covering intakes by workers and members of the public including children and pregnant or lactating women. The calculation of these coefficients conveniently divides into two distinct parts - the biokinetic and dosimetric. This paper gives a brief summary of the methods used to solve the biokinetic problem in the generation of dose coefficients on behalf of the ICRP, as implemented in the Health Protection Agency's internal dosimetry code PLEIADES. (author)

Modeling, Simulation, and Measurement of Balanced Antipodal Vivaldi (BAV) Antennas for Fully Polarimetric Forward-Looking Ground-Penetrating Radar (FLGPR) Receive Channels

Science.gov (United States)

2017-08-01

Current Vivaldi Elements and Replacement Antennas Considered The majority of the design process was conducted through modeling and simulation ...ARL-TR-8111 ● AUG 2017 US Army Research Laboratory Modeling, Simulation , and Measurement of Balanced Antipodal Vivaldi (BAV...ARL-TR-8111 ● AUG 2017 US Army Research Laboratory Modeling, Simulation , and Measurement of Balanced Antipodal Vivaldi (BAV) Antennas for

Antennas in inhomogeneous media

CERN Document Server

Galejs, Janis; Fock, V A; Wait, J R

2013-01-01

Antennas in Inhomogeneous Media details the methods of analyzing antennas in such inhomogeneous media. The title covers the complex geometrical configurations along with its variational formulations. The coverage of the text includes various conditions the antennas are subjected to, such as antennas in the interface between two media; antennas in compressible isotropic plasma; and linear antennas in a magnetoionic medium. The selection also covers insulated loops in lossy media; slot antennas with a stratified dielectric or isotropic plasma layers; and cavity-backed slot antennas. The book wil

The use of the ICRP principles for controlling risks from potential exposure

International Nuclear Information System (INIS)

Cunningham, R.; Gonzalez, A.J.

1991-01-01

Heretofore, ICRP recommendations for radiation protection mainly apply to radiation exposures that are expected to occur with near certainty during normal operation of radiation sources. It is anticipated that the new ICRP recommendations will deal more comprehensively with radiation safety by including consideration of exposure which might or might not occur, but for which a probability of occurrence can be assigned (potential exposure). This paper discusses issues and principles for a system of radiation safety which accommodates both radiation protection and nuclear safety standards and covers both normal and potential exposures. The principles are formulated by interpreting and extrapolating the principles of justification, optimization and dose limitation currently employed for normal exposure

Optimisation of Protection as applicable to geological disposal: the ICRP view

International Nuclear Information System (INIS)

Weiss, W.

2010-01-01

Wolfgang Weiss (BfS), vice-chair of ICRP Committee 4, recalled that the role of optimisation is to select the best protection options under the prevailing circumstances based on scientific considerations, societal concerns and ethical aspects as well as considerations of transparency. An important role of the concept of optimisation of protection is to foster a 'safety culture' and thereby to engender a state of thinking in everyone responsible for control of radiation exposures, such that they are continuously asking themselves the question, 'Have I done all that I reasonably can to avoid or reduce these doses?' Clearly, the answer to this question is a matter of judgement and necessitates co-operation between all parties involved and, as a minimum, the operating management and the regulatory agencies, but the dialogue would be more complete if other stakeholders were also involved. What kinds of checks and balances or factors would be needed to be considered for an 'optimal' system? Can indicators be identified? Quantitative methods may provide input to this dialogue but they should never be the sole input. The ICRP considers that the parameters to take into account include also social considerations and values, environmental considerations, as well as technical and economic considerations. Wolfgang Weiss approached the question of the distinction to be made between system optimisation (in the sense of taking account of social and economic as well as of all types of hazards) and optimisation of radiological protection. The position of the ICRP is that the system of protection that it proposes is based on both science (quantification of the health risk) and value judgement (what is an acceptable risk?) and optimisation is the recommended process to integrate both aspects. Indeed, there has been evolution since the old system of intervention levels to the new system, whereby, even if the level of the dose or risk (which is called constraint in ICRP-81 ) is met

Passive wireless antenna sensor for strain and crack sensing—electromagnetic modeling, simulation, and testing

International Nuclear Information System (INIS)

Yi, Xiaohua; Cho, Chunhee; Wang, Yang; Cooper, James; Tentzeris, Manos M; Leon, Roberto T

2013-01-01

This research investigates a passive wireless antenna sensor designed for strain and crack sensing. When the antenna experiences deformation, the antenna shape changes, causing a shift in the electromagnetic resonance frequency of the antenna. A radio frequency identification (RFID) chip is adopted for antenna signal modulation, so that a wireless reader can easily distinguish the backscattered sensor signal from unwanted environmental reflections. The RFID chip captures its operating power from an interrogation electromagnetic wave emitted by the reader, which allows the antenna sensor to be passive (battery-free). This paper first reports the latest simulation results on radiation patterns, surface current density, and electromagnetic field distribution. The simulation results are followed with experimental results on the strain and crack sensing performance of the antenna sensor. Tensile tests show that the wireless antenna sensor can detect small strain changes lower than 20 με, and can perform well at large strains higher than 10 000 με. With a high-gain reader antenna, the wireless interrogation distance can be increased up to 2.1 m. Furthermore, an array of antenna sensors is capable of measuring the strain distribution in close proximity. During emulated crack and fatigue crack tests, the antenna sensor is able to detect the growth of a small crack. (paper)

Radiological protection in medicine: work of ICRP Committee 3

International Nuclear Information System (INIS)

Vañó, E.; Cosset, J.M.; Rehani, M.M.

2012-01-01

Committee 3 of the International Commission on Radiological Protection (ICRP) is concerned with protection in medicine, and develops recommendations and guidance on the protection of patients, staff, and the public against radiation exposure in medicine. This paper presents an overview of the work of Committee 3 over recent years, and the work in progress agreed at the last annual meeting in Bethesda, MD in October 2011. The reports published by ICRP dealing with radiological protection in medicine in the last 10 years cover topics on: education and training in radiological protection; preventing accidental exposures in radiation therapy; dose to patients from radiopharmaceuticals; radiation safety aspects of brachytherapy; release of patients after therapy with unsealed radionuclides; managing patient dose in digital radiology and computed tomography; avoidance of radiation injuries from medical interventional procedures; pregnancy and medical radiation; and diagnostic reference levels in medical imaging. Three new reports will be published in the coming months dealing with aspects of radiological protection in fluoroscopically guided procedures outside imaging departments; cardiology; and paediatric radiology. The work in progress agreed by Committee 3 is also described.

New radiobiological findings bearing on the 1977 ICRP recommendations

International Nuclear Information System (INIS)

Dobson, R.L.

1979-01-01

Recent experiments on low-level irradiation during development raise questions relevant to ICRP Publication 26. Mice and monkeys were studied; the measured endpoint was the radiation-induced loss of female germ cells. Three issues are examined. The first is the numerical value of Q (quality factor) appropriate for low-energy beta rays. Comparisons of tritium with gamma radiation were made under conditions of chronic, low-level exposure, and the relative biological effectiveness (RBE) was found to approach 3. Its bearing on ICRP's recommendations concerning Q applicable to tritium is discussed. Second, female germ cells in squirrel monkeys before birth were discovered to be extraordinarily radiosensitive, more easily destroyed than those of mice. If this holds for other primates too, it has radiation-protection implications hitherto overlooked. Third, the contrast between massive germ-cell loss from chronic exposure in prenatal squirrel monkeys and reported radioresistance of oocytes to acute exposure in rhesus monkeys, unless due to species difference, suggests that during development protracted irradiation may be especially injurious. This also could have important radiation-protection implications and is under investigation

ICRP recommendations on 'managing patient dose in digital radiology'

International Nuclear Information System (INIS)

Vano, E.

2005-01-01

The International Commission on Radiological Protection (ICRP) approved the publication of a document on 'Managing patient dose in digital radiology' in 2003. The paper describes the content of the report and some of its key points, together with the formal recommendations of the Commission on this topic. With digital techniques exists not only the potential to improve the practice of radiology but also the risk to overuse radiation. The main advantages of digital imaging: wide dynamic range, post-processing, multiple viewing options, electronic transfer and archiving possibilities are clear but overexposures can occur without an adverse impact on image quality. It is expected that the ICRP report helps to profit from the benefits of this important technological advance in medical imaging with the best management of radiation doses to the patients. It is also expected to promote training actions before the digital techniques are introduced in the radiology departments and to foster the industry to offer enough technical and dosimetric information to radiologists, radiographers and medical physicists to help in the optimisation of the imaging. (authors)

Dose coefficients for radionuclides produced in high energy proton accelerator facilities. Coefficients for radionuclides not listed in ICRP publications

CERN Document Server

Kawai, K; Noguchi, H

2002-01-01

Effective dose coefficients, the committed effective dose per unit intake, by inhalation and ingestion have been calculated for 304 nuclides, including (1) 230 nuclides with half-lives >= 10 min and their daughters that are not listed in ICRP Publications and (2) 74 nuclides with half-lives < 10 min that are produced in a spallation target. Effective dose coefficients for inhalation of soluble or reactive gases have been calculated for 21 nuclides, and effective dose rates for inert gases have been calculated for 9 nuclides. Dose calculation was carried out using a general-purpose nuclear decay database DECDC developed at JAERI and a decay data library newly compiled from the ENSDF for the nuclides abundantly produced in a spallation target. The dose coefficients were calculated with the computer code DOCAP based on the respiratory tract model and biokinetic model of ICRP. The effective dose rates were calculated by considering both external irradiation from the surrounding cloud and irradiation of the lun...

Validating and comparing GNSS antenna calibrations

Science.gov (United States)

Kallio, Ulla; Koivula, Hannu; Lahtinen, Sonja; Nikkonen, Ville; Poutanen, Markku

2018-03-01

GNSS antennas have no fixed electrical reference point. The variation of the phase centre is modelled and tabulated in antenna calibration tables, which include the offset vector (PCO) and phase centre variation (PCV) for each frequency according to the elevations and azimuths of the incoming signal. Used together, PCV and PCO reduce the phase observations to the antenna reference point. The remaining biases, called the residual offsets, can be revealed by circulating and rotating the antennas on pillars. The residual offsets are estimated as additional parameters when combining the daily GNSS network solutions with full covariance matrix. We present a procedure for validating the antenna calibration tables. The dedicated test field, called Revolver, was constructed at Metsähovi. We used the procedure to validate the calibration tables of 17 antennas. Tables from the IGS and three different calibration institutions were used. The tests show that we were able to separate the residual offsets at the millimetre level. We also investigated the influence of the calibration tables from the different institutions on site coordinates by performing kinematic double-difference baseline processing of the data from one site with different antenna tables. We found small but significant differences between the tables.

Development of film antenna for diversity reception; Diversity taio film antenna no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Shigeta, K; Taniguchi, T; Kubota, K [Mazda Motor Corp., Hiroshima (Japan)

1997-10-01

Based on the principle of capacitance-loaded window antennas, a new film antenna construction pasting an antenna element on a defogger element printed on a rear window was found. The film antennas show high reception performance, and can be used as television diversity antennas or a VICS-FM multiplex antenna. This paper describes the antenna design concept, the antenna construction and the application to a recreational vehicle which styling is 1.3-Box wagon for the electric accessory. 2 refs., 11 figs.

A Novel Metamaterial MIMO Antenna with High Isolation for WLAN Applications

Directory of Open Access Journals (Sweden)

Nguyen Khac Kiem

2015-01-01

Full Text Available A compact 2×2 metamaterial-MIMO antenna for WLAN applications is presented in this paper. The MIMO antenna is designed by placing side by side two single metamaterial antennas which are constructed based on the modified composite right/left-handed (CRLH model. By adding another left-handed inductor, the total left-handed inductor of the modified CRLH model is increased remarkably in comparison with that of conventional CRLH model. As a result, the proposed metamaterial antenna achieves 60% size reduction in comparison with the unloaded antenna. The MIMO antenna is electrically small (30 mm × 44 mm with an edge-to-edge separation between two antennas of 0.06λ0 at 2.4 GHz. In order to reduce the mutual coupling of the antenna, a defected ground structure (DGS is inserted to suppress the effect of surface current between elements of the proposed antenna. The final design of the MIMO antenna satisfies the return loss requirement of less than −10 dB in a bandwidth ranging from 2.38 GHz to 2.5 GHz, which entirely covers WLAN frequency band allocated from 2.4 GHz to 2.48 GHz. The antenna also shows a high isolation coefficient which is less than −35 dB over the operating frequency band. A good agreement between simulation and measurement is shown in this context.

Earth-Mars Telecommunications and Information Management System (TIMS): Antenna Visibility Determination, Network Simulation, and Management Models

Science.gov (United States)

Odubiyi, Jide; Kocur, David; Pino, Nino; Chu, Don

1996-01-01

This report presents the results of our research on Earth-Mars Telecommunications and Information Management System (TIMS) network modeling and unattended network operations. The primary focus of our research is to investigate the feasibility of the TIMS architecture, which links the Earth-based Mars Operations Control Center, Science Data Processing Facility, Mars Network Management Center, and the Deep Space Network of antennae to the relay satellites and other communication network elements based in the Mars region. The investigation was enhanced by developing Build 3 of the TIMS network modeling and simulation model. The results of several 'what-if' scenarios are reported along with reports on upgraded antenna visibility determination software and unattended network management prototype.

Board advice following publication of the 1990 Recommendations of ICRP

CERN Document Server

United Kingdom. At. Energy Res. Establ. Nat. Radiolog. Protect. Board. Harwell

1991-01-01

The International Commission on Radiological Protection (ICRP) has published new Recommendations and the board has a statutory duty to advise Government and those with responsibilities for radiation protection on the acceptability to and the applicability in the UK of those Recommendations. The Board wishes to consult widely before finalising the advice which is proposed in this document. In general, the Board endorses the conceptual framework for radiological protection recommended by ICRP. In particular, the distinction between practices and intervention is useful and is consistent with the way in which the Board has presented its recent advice. A major new concept is that of a constraint. The Board believes that the introduction of constraints provides a powerful method for improving protection against ionising radiation. The advice in this consultative document is for maximum generic values of dose constraints for both workers and the public. Finally the Board proposes to endorse the use of the radiologic...

Current status on preparation of dose conversion factors based on 1990 ICRP recommendations

International Nuclear Information System (INIS)

Yoshizawa, Michio

1996-01-01

The current status of arrangement of dose conversion factors for operational quantities are explained on the basis of 1995 ICRP-ICRU recommendations. The dose conversion factors of photon, neutron and electron were recommended by ICRP Publ. 74. It's contents are described. The relation between new dose conversion factors and the laws in connection with protecting radiation are explained. The dose conversion factors of 1 cm-, 3 mm- and 70 μm - dose equivalent which were introduced into the laws connected therewith in Japan are accepted the same values of ICRP Publ. 51 for photon and neutron. I mentioned the points of discussing about new dose conversion factors which are expected to be recommended. The laws have to show the dose conversion factors to be used by calculation and estimation of radiation shield, etc. The limit of energy of ICRU individual dose equivalent for photon is now until 1 MeV, but the value is insufficient and necessary to 10 MeV as same as the ambient dose equivalent in due consideration of atomic energy facilities. JAERI is preparing these dose conversion factors now. (S.Y.)

Comparison of Antenna Array Systems Using OFDM for Software Radio via the SIBIC Model

Directory of Open Access Journals (Sweden)

Robert D. Palmer

2005-09-01

Full Text Available This paper investigates the performance of two candidates for software radio WLAN, reconfigurable OFDM modulation and antenna diversity, in an indoor environment. The scenario considered is a 20 m×10 m×3 m room with two base units and one mobile unit. The two base units use omnidirectional antennas to transmit and the mobile unit uses either a single antenna with equalizer, a fixed beamformer with equalizer, or an adaptive beamformer with equalizer to receive. The modulation constellation of the data is QPSK and 16-QAM. The response of the channel at the mobile unit is simulated using a three-dimensional indoor WLAN propagation model that generates multipath components with realistic spatial and temporal correlation. An underlying assumption of the scenario is that existing antenna hardware is available and could be exploited if software processing resources are allocated. The results of the simulations indicate that schemes using more resources outperform simpler schemes in most cases. This implies that desired user performance could be used to dynamically assign software processing resources to the demands of a particular indoor WLAN channel if such resources are available.

Experience in the application of the new ICRP recommendations in Hungary

International Nuclear Information System (INIS)

Sztanyik, L.B.; Bojtor, I.

1982-01-01

In connection with the introduction of nuclear power in Hungary and the increasing use of radioactive substances and other sources of ionizing radiation for industrial, medical and research purposes, comprehensive legislation on the use of atomic energy has recently been introduced. An Atomic Energy Act was passed by Parliament, the supreme legislative body of the country, in 1980. Accompanying this, an enacting clause was issued by the Council of Ministers, and several ministerial orders were published subsequently on particular rules and regulations for atomic energy applications. In preparing this legislation, the new principles and recommendations of the ICRP on radiation protection were taken into consideration as much as possible. The basic principles of radiation protection, including justification of the proposed operation or practice, reduction of any necessary exposure to a level as low as is reasonably achievable, and limitation of dose to individuals to the values recommended by the ICRP have been adopted and incorporated into the text of the Act. Disagreement has been found, however, when the balancing of costs and benefits as well as the acceptability of the level of risk were proposed for inclusion. In the latter question some professional objections have also been encountered. Limitation of individual monitoring and assessment of dose to workers designated to work in Condition A, as recommended by the ICRP, seems to involve a risk that a major proportion of ''overexposures'', i.e. exposures exceeding the investigation level, remains undiscovered. (author)

Antenna toolkit

CERN Document Server

Carr, Joseph

2006-01-01

Joe Carr has provided radio amateurs and short-wave listeners with the definitive design guide for sending and receiving radio signals with Antenna Toolkit 2nd edition.Together with the powerful suite of CD software, the reader will have a complete solution for constructing or using an antenna - bar the actual hardware! The software provides a simple Windows-based aid to carrying out the design calculations at the heart of successful antenna design. All the user needs to do is select the antenna type and set the frequency - a much more fun and less error prone method than using a con

HUMTRN: documentation and verification for an ICRP-based age- and sex-specific human simulation model for radionuclide dose assessment

International Nuclear Information System (INIS)

Gallegos, A.F.; Wenzel, W.J.

1984-06-01

The dynamic human simulation model HUMTRN is designed specifically as a major module of BIOTRAN to integrate climatic, hydrologic, atmospheric, food crop, and herbivore simulation with human dietary and physiological characteristics, and metabolism and radionuclides to predict radiation doses to selected organs of both sexes in different age groups. The model is based on age- and weight-specific equations developed for predicting human radionuclide transport from metabolic and physical characteristics. These characteristics are modeled from studies documented by the International Commission on Radiological Protection (ICRP 23). HUMTRN allows cumulative doses from uranium or plutonium radionuclides to be predicted by modeling age-specific anatomical, physiological, and metabolic properties of individuals between 1 and 70 years of age and can track radiation exposure and radionuclide metabolism for any age group for specified daily or yearly time periods. The simulated daily dose integration of eight or more simultaneous air, water, and food intakes gives a new, comprehensive, dynamic picture of radionuclide intake, uptake, and hazard analysis for complex scenarios. A detailed example using site-specific data based on the Pantex studies is included for verification. 14 references, 24 figures, 10 tables

Antenna theory: Analysis and design

Science.gov (United States)

Balanis, C. A.

The book's main objective is to introduce the fundamental principles of antenna theory and to apply them to the analysis, design, and measurements of antennas. In a description of antennas, the radiation mechanism is discussed along with the current distribution on a thin wire. Fundamental parameters of antennas are examined, taking into account the radiation pattern, radiation power density, radiation intensity, directivity, numerical techniques, gain, antenna efficiency, half-power beamwidth, beam efficiency, bandwidth, polarization, input impedance, and antenna temperature. Attention is given to radiation integrals and auxiliary potential functions, linear wire antennas, loop antennas, linear and circular arrays, self- and mutual impedances of linear elements and arrays, broadband dipoles and matching techniques, traveling wave and broadband antennas, frequency independent antennas and antenna miniaturization, the geometrical theory of diffraction, horns, reflectors and lens antennas, antenna synthesis and continuous sources, and antenna measurements.

The work of ICRP on the ethical foundations of the system of radiological protection

International Nuclear Information System (INIS)

Cho, Kun-Woo

2017-01-01

The International Commission on Radiological Protection (ICRP) has established Task Group 94 (TG 94) to develop a publication on the ethical foundations of the system of radiological protection aiming to consolidate the basis of ICRP's recommendations, to improve the understanding of the system and to provide a basis for communication on radiation risk and its perception. Through the review of the publications of the Commission and the conduct of a series of workshops, TG 94 has identified the key components of the ethical theories and principles relevant to the system of radiological protection. The purpose of eliciting the ethical values underpinning the system of radiological protection is not only to clarify the rationale of the recommendations made by the Commission, but also to assist in discussions related to its practical implementation. The report nearing completion by TG 94 will present the key steps concerning the scientific, ethical and practical evolutions of the system of radiological protection since the first ICRP publication in 1928, describe the core ethical values underpinning the present system and address the key procedural aspects for its implementation. (authors)

Fractal Based Triple Band High Gain Monopole Antenna

Science.gov (United States)

Pandey, Shashi Kant; Pandey, Ganga Prasad; Sarun, P. M.

2017-10-01

A novel triple-band microstrip fed planar monopole antenna is proposed and investigated. A fractal antenna is created by iterating a narrow pulse (NP) generator model at upper side of modified ground plane, which has a rhombic patch, for enhancing the bandwidth and gain. Three iterations are carried out to study the effects of fractal geometry on the antenna performance. The proposed antenna can operate over three frequency ranges viz, 3.34-4.8 GHz, 5.5-10.6 GHz and 13-14.96 GHz suitable for WLAN 5.2/5.8 GHz, WiMAX 3.5/5.5 GHz and X band applications respectively. Simulated and measured results are in good agreements with each others. Results show that antenna provides wide/ultra wide bandwidths, monopole like radiation patterns and very high antenna gains over the operating frequency bands.

Design and Simulation of Horn Antenna Using CST Software for GPR System

Science.gov (United States)

Joret, Ariffuddin; Sulong, M. S.; Abdullah, M. F. L.; Madun, Aziman; Haimi Dahlan, Samsul

2018-04-01

Detection of underground object can be made using a GPR system. This system is classified as a non-destructive technique (NDT) where the ground areas need not to be excavated. The technique used by the GPR system is by measuring the reflection of electromagnetic wave signal produced and detected by antenna which is known as the transmitter and the receiver antenna. In this study, a GPR system was studied by means of simulation using a Horn antenna as a transceiver antenna. The electromagnetic wave signal in this simulation is produced by current signal of an antenna which having a shape of modulation of Gaussian pulse which is having spectrum from 8 GHz until 12 GHz. CST and MATLAB Software are used in this GPR system simulation. A model of a Horn antenna has been designed using the CST software before the GPR’s system simulation modeled by adding a model of background in front of the Horn antenna. The simulation results show that the output signal of the Horn antenna can be used in detecting embedded object which are made from material of wood and iron. In addition, the simulation result has successfully developed a 3D model image of the GPR system using output signal of the Horn antenna. The embedded iron object in the GPR system simulation can be seen clearly by using this 3D image.

ALI and DAC for transuranic elements based on the metabolic data presented in ICRP Publication 48

International Nuclear Information System (INIS)

Togawa, Orihiko; Yamaguchi, Yukichi; Homma, Toshimitsu

1987-07-01

The recently published ICRP report, ICRP Publication 48, presents the new metabolic data of some transuranic elements, compared with those employed in the calculation of ALI and DAC in ICRP Publication 30. Values of ALI and DAC for 72 radionuclides were calculated using the metabolic data presented in the Publication 48. The calculation was performed by a computer code system DOSDAC, which can systematically calculate ALI and DAC by the same method as that described in the Publication 30. The calculated values of ALI and DAC were tabulated in the same format as that of the supplements to the Publication 30. For the convenience of using in the dose assessment, also given are values of committed effective dose equivalent per intake of unit activity. It is expected that these values will be applied to the radiation protection purposes. (author)

A New Blind Pointing Model Improves Large Reflector Antennas Precision Pointing at Ka-Band (32 GHz)

Science.gov (United States)

Rochblatt, David J.

2009-01-01

The National Aeronautics and Space Administration (NASA), Jet Propulsion Laboratory (JPL)-Deep Space Network (DSN) subnet of 34-m Beam Waveguide (BWG) Antennas was recently upgraded with Ka-Band (32-GHz) frequency feeds for space research and communication. For normal telemetry tracking a Ka-Band monopulse system is used, which typically yields 1.6-mdeg mean radial error (MRE) pointing accuracy on the 34-m diameter antennas. However, for the monopulse to be able to acquire and lock, for special radio science applications where monopulse cannot be used, or as a back-up for the monopulse, high-precision open-loop blind pointing is required. This paper describes a new 4th order pointing model and calibration technique, which was developed and applied to the DSN 34-m BWG antennas yielding 1.8 to 3.0-mdeg MRE pointing accuracy and amplitude stability of 0.2 dB, at Ka-Band, and successfully used for the CASSINI spacecraft occultation experiment at Saturn and Titan. In addition, the new 4th order pointing model was used during a telemetry experiment at Ka-Band (32 GHz) utilizing the Mars Reconnaissance Orbiter (MRO) spacecraft while at a distance of 0.225 astronomical units (AU) from Earth and communicating with a DSN 34-m BWG antenna at a record high rate of 6-megabits per second (Mb/s).

Antenna conditioning with insulating antenna tiles in Phaedrus-T

International Nuclear Information System (INIS)

Intrator, T.; Probert, P.; Doczy, M.; Diebold, D.; Brouchous, D.

1994-01-01

In the course of our Alfven wave heating and current drive experiments several different two and four strap antennas have been installed in Phaedrus-T. The motivation focusing the redesign of the antenna into a four strap design was to enable traveling wave phasing, and to reduce the k parallel ∼0 component of the wavenumber spectrum, and consequent edge power deposition. The latest modifications to the 4 strap antenna have dramatically improved its behavior, and enabled us to suppress its RF power induced impurity generation. The remaining gas reflux fueling is significant and is not local to the antenna

Modelling the Impact of Ground Planes on Antenna Radiation Using the Method of Auxiliary Sources

DEFF Research Database (Denmark)

Larsen, Niels Vesterdal; Breinbjerg, Olav

2007-01-01

The Method of Auxiliary Sources is employed to model the impact of finite ground planes on the radiation from antennas. In many cases the computational cost of available commercial tools restricts the simulations to include only a small ground plane or, by use of the image principle, the infinitely...... large ground plane. The method proposed here makes use of results from such simulations to model large and moderate-sized finite ground planes. The method is applied to 3 different antenna test cases and a total of 5 different ground planes. Firstly it is validated through comparison with reference...... and measured reference solutions and the method is thus found to be a useful tool in determining the impact of finite ground planes....

Nuclear decay data for dosimetry calculation. Revised data of ICRP Publication 38

International Nuclear Information System (INIS)

Endo, Akira; Yamaguchi, Yasuhiro

2005-02-01

New nuclear decay data used for dose calculation have been compiled for 1034 radionuclides, which are significant in medical, environmental and occupational exposures. The decay data were assembled from decay data sets of the Evaluated Nuclear Structure Data File (ENSDF), the latest version as of 2003. Basic nuclear properties in the ENSDF that are particularly important for calculating energies and intensities of radiations were examined and updated by referring to UNBASE2003/AME2003, the database for nuclear and decay properties of nuclides. In addition, modification of incomplete ENSDF was done for their format errors, level schemes, normalization records, and so on. The energies and intensities of emitted radiations by the nuclear decay and the subsequent atomic process were computed from the ENSDF using the computer code EDISTR04. EDISTR04 is an enhanced version of EDISTR used for assembling ICRP Publication 38 (ICRP38), and incorporates updates of atomic data and computation methods for calculating atomic radiations and spontaneous fission radiations. Quality assurance of the compiled data has been made by comparisons with various experimental data and decay databases prepared from different computer codes and data libraries. A package of the data files, called DECDC2 (Nuclear DECay Data for Dosimetry Calculation, Version 2), will succeed ICRP38 that has been used extensively in dose calculation and will be utilized in various fields. (author)

Modeling of the Near Field Coupling Between an External Loop and an Implantable Spiral Chip Antennas in Biosensor Systems

Science.gov (United States)

Simons, Rainee N.; Miranda, Felix A.

2006-01-01

In this paper, the near field coupling between an external hand-held loop antenna and an implantable miniature (1x1 mm) printed square spiral chip antenna used in bio-MEMS sensors for contact-less powering and RF telemetry is investigated. The loop and the spiral are inductively coupled and effectively form a transformer. The numerical results include the quasi-stationary magnetic field pattern of the implanted antenna, near zone wave impedance as a function of the radial distance and the values of the lumped elements in the equivalent circuit model for the transformer.

Role IAEA implementation of ICRP-60 on regulations the safe transport of radioactive material

International Nuclear Information System (INIS)

Elshinawy, R.K.M.; Gomaa, M.A.

1994-01-01

In november 1990, the (ICRP) adopted its 1990 recommendations (ICRP-60) ( 1). These recommendations will significantly influence not only IAEA's basic safety standards (safety series 9) ( 2), but also the IAEA regulations for the safe transport of radioactive material ( 3) and its supporting documents ( 4-6). IAEA experts are currently engaged in the revision of the transport regulations. This revision process led to the publication of the revised transport regulations of 1966. The transport regulations are developed to ensure safety during movement of radioactive materials, and to provide reasonable assurance that the transport activities comply with the basic safety standards for radiation protection

ICRP PUBLICATION 122: radiological protection in geological disposal of long-lived solid radioactive waste.

Science.gov (United States)

Weiss, W; Larsson, C-M; McKenney, C; Minon, J-P; Mobbs, S; Schneider, T; Umeki, H; Hilden, W; Pescatore, C; Vesterlind, M

2013-06-01

This report updates and consolidates previous recommendations of the International Commission on Radiological Protection (ICRP) related to solid waste disposal (ICRP, 1985, 1997b, 1998). The recommendations given apply specifically to geological disposal of long-lived solid radioactive waste. The report explains how the ICRP system of radiological protection described in Publication 103 (ICRP, 2007) can be applied in the context of the geological disposal of long-lived solid radioactive waste. Although the report is written as a standalone document, previous ICRP recommendations not dealt with in depth in the report are still valid. The 2007 ICRP system of radiological protection evolves from the previous process-based protection approach relying on the distinction between practices and interventions by moving to an approach based on the distinction between three types of exposure situation: planned, emergency and existing. The Recommendations maintains the Commission's three fundamental principles of radiological protection namely: justification, optimisation of protection and the application of dose limits. They also maintain the current individual dose limits for effective dose and equivalent dose from all regulated sources in planned exposure situations. They re-enforce the principle of optimisation of radiological protection, which applies in a similar way to all exposure situations, subject to restrictions on individual doses: constraints for planned exposure situations, and reference levels for emergency and existing exposure situations. The Recommendations also include an approach for developing a framework to demonstrate radiological protection of the environment. This report describes the different stages in the life time of a geological disposal facility, and addresses the application of relevant radiological protection principles for each stage depending on the various exposure situations that can be encountered. In particular, the crucial factor that

ICRP PUBLICATION 122: Radiological Protection in Geological Disposal of Long-lived Solid Radioactive Waste

International Nuclear Information System (INIS)

Weiss, W.; Larsson, C-M.; McKenney, C.; Minon, J-P.; Mobbs, S.; Schneider, T.; Umeki, H.; Hilden, W.; Pescatore, C.; Vesterlind, M.

2013-01-01

This report updates and consolidates previous recommendations of the International Commission on Radiological Protection (ICRP) related to solid waste disposal (ICRP, 1985, 1997b, 1998). The recommendations given apply specifically to geological disposal of long-lived solid radioactive waste. The report explains how the ICRP system of radiological protection described in Publication 103 (ICRP, 2007) can be applied in the context of the geological disposal of long-lived solid radioactive waste. Although the report is written as a standalone document, previous ICRP recommendations not dealt with in depth in the report are still valid. The 2007 ICRP system of radiological protection evolves from the previous process-based protection approach relying on the distinction between practices and interventions by moving to an approach based on the distinction between three types of exposure situation: planned, emergency and existing. The Recommendations maintains the Commission’s three fundamental principles of radiological protection namely: justification, optimisation of protection and the application of dose limits. They also maintain the current individual dose limits for effective dose and equivalent dose from all regulated sources in planned exposure situations. They re-enforce the principle of optimisation of radiological protection, which applies in a similar way to all exposure situations, subject to restrictions on individual doses: constraints for planned exposure situations, and reference levels for emergency and existing exposure situations. The Recommendations also include an approach for developing a framework to demonstrate radiological protection of the environment. This report describes the different stages in the life time of a geological disposal facility, and addresses the application of relevant radiological protection principles for each stage depending on the various exposure situations that can be encountered. In particular, the crucial factor that

Superconducting microstrip antennas: An experimental comparison of two feeding methods

International Nuclear Information System (INIS)

Richard, M.A.; Claspy, P.C.; Bhasin, K.B.

1993-01-01

The recent discovery of high-temperature superconductors (HTS's) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. In this paper, two methods for feeding HTS microstrip antennas at K and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gap-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals

Calculated shape dependence of electromagnetic field in tip-enhanced Raman scattering by using a monopole antenna model

Science.gov (United States)

Kitahama, Yasutaka; Itoh, Tamitake; Suzuki, Toshiaki

2018-05-01

To evaluate the shape of an Ag tip with regard to tip-enhanced Raman scattering (TERS) signal, the enhanced electromagnetic (EM) field and scattering spectrum, arising from surface plasmon resonance at the apex of the tip, were calculated using a finite-difference time domain (FDTD) method. In the calculated forward scattering spectra from the smooth Ag tip, the band appeared within the visible region, similar to the experimental results and calculation for a corrugated Ag cone. In the FDTD calculation of TERS, the Ag tip acting as a monopole antenna was adopted by insertion of a perfect electric conductor between the root of the tip and a top boundary surface of the calculation space. As a result, the EM field was only enhanced at the apex. The shape dependence i.e. the EM field calculated at the apex with various curvatures on the different tapered tips, obtained using the monopole antenna model, was different from that simulated using a conventional dipole antenna model.

Characterization of local heat fluxes around ICRF antennas on JET

Energy Technology Data Exchange (ETDEWEB)

Campergue, A.-L. [Ecole Nationale des Ponts et Chaussées, F77455 Marne-la-Vallée (France); Jacquet, P.; Monakhov, I.; Arnoux, G.; Brix, M.; Sirinelli, A. [Euratom/CCFE Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Bobkov, V. [Max-Planck-Institut für Plasmaphysik, EURATOM-Assoziation, Garching (Germany); Milanesio, D. [Politecnico di Torino, Department of Electronics, Torino (Italy); Colas, L. [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Collaboration: JET-EFDA Contributors

2014-02-12

When using Ion Cyclotron Range of Frequency (ICRF) heating, enhanced power deposition on Plasma-Facing Components (PFCs) close to the antennas can occur. Experiments have recently been carried out on JET with the new ITER-Like-Wall (ILW) to characterize the heat fluxes on the protection of the JET ICRF antennas, using Infra-Red (IR) thermography measurement. The measured heat flux patterns along the poloidal limiters surrounding powered antennas were compared to predictions from a simple RF sheath rectification model. The RF electric field, parallel to the static magnetic field in front of the antenna, was evaluated using the TOPICA code, integrating a 3D flattened model of the JET A2 antennas. The poloidal density variation in front of the limiters was obtained from the mapping of the Li-beam or edge reflectometry measurements using the flux surface geometry provided by EFIT equilibrium reconstruction. In many cases, this simple model can well explain the position of the maximum heat flux on the different protection limiters and the heat-flux magnitude, confirming that the parallel RF electric field and the electron plasma density in front of the antenna are the main driving parameters for ICRF-induced local heat fluxes.

Surface accuracy analysis and mathematical modeling of deployable large aperture elastic antenna reflectors

Science.gov (United States)

Coleman, Michael J.

One class of deployable large aperture antenna consists of thin light-weight parabolic reflectors. A reflector of this type is a deployable structure that consists of an inflatable elastic membrane that is supported about its perimeter by a set of elastic tendons and is subjected to a constant hydrostatic pressure. A design may not hold the parabolic shape to within a desired tolerance due to an elastic deformation of the surface, particularly near the rim. We can compute the equilibrium configuration of the reflector system using an optimization-based solution procedure that calculates the total system energy and determines a configuration of minimum energy. Analysis of the equilibrium configuration reveals the behavior of the reflector shape under various loading conditions. The pressure, film strain energy, tendon strain energy, and gravitational energy are all considered in this analysis. The surface accuracy of the antenna reflector is measured by an RMS calculation while the reflector phase error component of the efficiency is determined by computing the power density at boresight. Our error computation methods are tailored for the faceted surface of our model and they are more accurate for this particular problem than the commonly applied Ruze Equation. Previous analytical work on parabolic antennas focused on axisymmetric geometries and loads. Symmetric equilibria are not assumed in our analysis. In addition, this dissertation contains two principle original findings: (1) the typical supporting tendon system tends to flatten a parabolic reflector near its edge. We find that surface accuracy can be significantly improved by fixing the edge of the inflated reflector to a rigid structure; (2) for large membranes assembled from flat sheets of thin material, we demonstrate that the surface accuracy of the resulting inflated membrane reflector can be improved by altering the cutting pattern of the flat components. Our findings demonstrate that the proper choice

Experimental measurements of the ion cyclotron antennas' coupling and rf characteristics

International Nuclear Information System (INIS)

Hoffman, D.J.; Baity, F.W.; Becraft, W.R.; Caughman, J.B.O.; Owens, T.L.

1985-01-01

The rf coupling capabilities and characteristics of various antennas have been measured. The tested antenna configurations include the simple loop antenna operated at resonant lengths as used on Alcator-C, the cavity antenna proposed for Doublet III-D and the resonant double loop, asymmetric resonant double loop, and U-slot antennas. Models of the voltage, magnetic fields outside the structure, and current have been correlated with the measurements made on these antennas. From these measurements and from typical observations of ICRH coupling in tokamaks, we are studying power and frequency limitations on each antenna and the causes of the limitations. A comparison of the technology, performance, and power limitations of each type of antenna is presented

User Interaction with Inverted-F Antennas Integrated into Laptop PCMCIA Cards

Directory of Open Access Journals (Sweden)

J. Guterman

2008-06-01

Full Text Available This paper evaluates the overall laptop integration effects on the performance of commercial 2.4 GHz Inverted-F antennas built into PCMCIA cards. A generic laptop model is used to represent the antenna housing effects while an anatomical shape homogenous human model is used to estimate the electromagnetic interaction between the antenna and the user. The antenna performance is evaluated for different card locations in terms of reflection coefficient, far-field gain pattern and radiation efficiency. The human exposure to EM radiation is analyzed in terms of Specific Absorption Rate.

Application of the Commission’s recommendations: the activities of ICRP Committee 4

International Nuclear Information System (INIS)

Lochard, Jacques

2012-01-01

Committee 4 of the International Commission on Radiological Protection (ICRP) is responsible for developing principles, recommendations, and guidance on the protection of man against radiation exposure; and considering their practical application in all exposure situations. The Committee also acts as a major point of contact between ICRP and other international organisations and professional bodies concerned with protection against ionising radiation. The current work of the Committee involves the development of a series of reports on implementation of the 2007 Recommendations, and a reflection on the ethical foundations of the radiological protection system. Following the accident in Fukushima, Committee 4 also initiated an analysis of management of the consequences of the accident, with the objective of revising, if necessary, the Commission’s publications on emergency and post-accident situations.

Quasi-optical antenna-mixer-array design for terahertz frequencies

Science.gov (United States)

Guo, Yong; Potter, Kent A.; Rutledge, David B.

1992-01-01

A new quasi-optical antenna-mixer-array design for terahertz frequencies is presented. In the design, antenna and mixer are combined into an entity, based on the technology in which millimeter-wave horn antenna arrays have been fabricated in silicon wafers. It consists of a set of forward- and backward-looking horns made with a set of silicon wafers. The front side is used to receive incoming signal, and the back side is used to feed local oscillator signal. Intermediate frequency is led out from the side of the array. Signal received by the horn array is picked up by antenna probes suspended on thin silicon-oxynitride membranes inside the horns. Mixer diodes will be located on the membranes inside the horns. Modeling of such an antenna-mixer-array design is done on a scaled model at microwave frequencies. The impedance matching, RF and LO isolation, and patterns of the array have been tested and analyzed.

Antenna Controller Replacement Software

Science.gov (United States)

Chao, Roger Y.; Morgan, Scott C.; Strain, Martha M.; Rockwell, Stephen T.; Shimizu, Kenneth J.; Tehrani, Barzia J.; Kwok, Jaclyn H.; Tuazon-Wong, Michelle; Valtier, Henry; Nalbandi, Reza;

Derived limits for radiological protection against ionizing radiation based on ICRP-60 recommendations

International Nuclear Information System (INIS)

Jang, Si Young; Lee, Byung Soo

2000-01-01

In Korea the dose limits are reduced and are set at the ICRP-60 limits. However, derived limits tabulated as MPC in air and water are sill specified in Notice Nol 98-12. There are some discrepancies between the primary dose limits and MPCs in air and water. Therefore, in order to accept ICRP-60 recommendations fully, derived limits such as ALI, DAC, ECL for radiological protection against ionizing radiation based on ICRP-60 recommendations were calculated using modified methods of those of 10 CFR part 20, dose limits and committed effective dose coefficients of the Basic Safety Standards of the IAEA. The derived limits in this study were also compared with those prescribed in 10 CFR part 20 as well as MPCs of Notice No.98-12 in order to analyze the impact of implementing derived limits on nuclear facilities. ECLs in air and water for the control of radioactive discharge into the environment in this study are shown to have lower values (i.e. more conservative), for most part, than those in Notice No. 98-12. Especially, for uranium elements, ECLs in water are approximately a magnitude in the order of two lower than those in Notice No. 98-12. (author)

Outlines of ICRP publication 74 and new dose conversion coefficients for external radiation

International Nuclear Information System (INIS)

Yamaguchi, Yasuhiro

1998-01-01

Combined task group of ICRP and ICRU reported the ICRP Publication 74 (1996) which is a summary report of their collection, analysis and evaluation of many data and dose conversion coefficients. Concerning the new coefficients, the author described this review as follows: History until Publication 74. Doses recommended at present: for protection quantity, the mean absorption dose of organ and tissue, equivalent dose and effective dose and for operational quantity, the ambient dose equivalent, directional dose equivalent and individual dose equivalent. Changes which can have an influence on the dose evaluation; introduction of radiation weighting factor (WR), changing of tissue weighting factor (WR), changing of the equation for Q-L relation and updating of physical data. New dose conversion coefficients; for photon, neutron and electron. Comparison of new and present coefficients; concerning the quality factor Q, particularly for neutron Q. New relations of protection and operational quantities; for field and individual monitoring. General conclusion of Publication 74. The Publication gives a certain direction for problems in evaluation of external exposure dose which have been discussed since the ICRP Fundamental Recommendation 1990 was issued. However, there still remain many problems especially in validity of the WR and of equation for Q-L relation. (K.H.)

PBG based terahertz antenna for aerospace applications

CERN Document Server

Choudhury, Balamati; Jha, Rakesh Mohan

2016-01-01

This book focuses on high-gain antennas in the terahertz spectrum and their optimization. The terahertz spectrum is an unallocated EM spectrum, which is being explored for a number of applications, especially to meet increasing demands of high data rates for wireless space communications. Space communication systems using the terahertz spectrum can resolve the problems of limited bandwidth of present wireless communications without radio-frequency interference. This book describes design of such high-gain antennas and their performance enhancement using photonic band gap (PBG) substrates. Further, optimization of antenna models using evolutionary algorithm based computational engine has been included. The optimized high-performance compact antenna may be used for various wireless applications, such as inter-orbital communications and on-vehicle satellite communications.

Characteristics of the wire biconical antenna used for EMC measurements

Science.gov (United States)

Austin, Brian A.; Fourie, Andre P. C.

1991-08-01

The characteristics of a wire biconical antenna that determine its antenna factor were computed by using the method of moments code NEC-2. A fairly extensive validation exercise was conducted from which a suitable computer model was derived. The input impedance, gain, and radiation patterns of the antenna were computed for special cases where the biconical antenna is used above a conducting ground plane for open-field EMC (electromagnetic compatibility) testing. The effects of height above the ground plane and polarization of the antenna on these parameters were found and the antenna factor was corrected for them. The current distribution along the antenna elements was also examined, and it was found that significant pattern distortion can occur at some frequencies when a horizontal wire biconical antenna is used close to the ground. These results will allow this broadband antenna to be used with confidence in applications where previously only resonant dipoles were specified.

A Rectangular Planar Spiral Antenna for GIS Partial Discharge Detection

Directory of Open Access Journals (Sweden)

Xiaoxing Zhang

2014-01-01

Full Text Available A rectangular planar spiral antenna sensor was designed for detecting the partial discharge in gas insulation substations (GIS. It can expediently receive electromagnetic waves leaked from basin-type insulators and can effectively suppress low frequency electromagnetic interference from the surrounding environment. Certain effective techniques such as rectangular spiral structure, bow-tie loading, and back cavity structure optimization during the antenna design process can miniaturize antenna size and optimize voltage standing wave ratio (VSWR characteristics. Model calculation and experimental data measured in the laboratory show that the antenna possesses a good radiating performance and a multiband property when working in the ultrahigh frequency (UHF band. A comparative study between characteristics of the designed antenna and the existing quasi-TEM horn antenna was made. Based on the GIS defect simulation equipment in the laboratory, partial discharge signals were detected by the designed antenna, the available quasi-TEM horn antenna, and the microstrip patch antenna, and the measurement results were compared.

3D Printing Electrically Small Spherical Antennas

DEFF Research Database (Denmark)

Kim, Oleksiy S.

2013-01-01

3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations.......3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations....

ICRP recommendations in the present and in the short term

International Nuclear Information System (INIS)

Valentin, Jack

2003-01-01

The recommendations of ICRP are either re-stated or revised at intervals of about 15 years, most recently in 1990. The protection philosophy in Publication 60 comprises justification of the practice or intervention considered; optimisation of protection; dose and risk limits and constraints to restrict the options in optimisation. For medical exposures, dose and risk limits and formal constraints are irrelevant, but Diagnostic Reference Levels serve a similar purpose. Building on this foundation, ICRP plans to issue its next recommendations around 2005. The 2005 Recommendations are likely to emphasise protection of the individual more than protection of society; to aim at protection of non-human species as well as man; to summarise and simplify advice given in various reports after Publication 60, and to be formatted as concise recommendations underpinned by separate publications with more detail. The draft will be circulated and comments will be discussed in 2004 with a view approval of the recommendations in 2005 and publication in 2005 or 2006. Thus, integration into legislation may be possible sometime between 2006 and 2010. (author)

Applicability of dose conversion coefficients of ICRP 74 to Asian adult males: Monte Carlo simulation study

International Nuclear Information System (INIS)

Lee, Choonsik; Lee, Choonik; Lee, Jai-Ki

2007-01-01

International Commission on Radiological Protection (ICRP) reported comprehensive dose conversion coefficients for adult population, which is exposed to external photon sources in the Publication 74. However, those quantities were calculated from so-called stylized (or mathematical) phantoms composed of simplified mathematical surface equations so that the discrepancy between the phantoms and real human anatomy has been investigated by several authors using Caucasian-based voxel phantoms. To address anatomical and racial limitations of the stylized phantoms, several Asian-based voxel phantoms have been developed by Korean and Japanese investigators, independently. In the current study, photon dose conversion coefficients of ICRP 74 were compared with those from a total of five Asian-based male voxel phantoms, whose body dimensions were almost identical. Those of representative radio-sensitive organs (testes, red bone marrow, colon, lungs, and stomach), and effective dose conversion coefficients were obtained for comparison. Even though organ doses for testes, colon and lungs, and effective doses from ICRP 74 agreed well with those from Asian voxel phantoms within 10%, absorbed doses for red bone marrow and stomach showed significant discrepancies up to 30% which was mainly attributed to difference of phantom description between stylized and voxel phantoms. This study showed that the ICRP 74 dosimetry data, which have been reported to be unrealistic compared to those from Caucasian-based voxel phantoms, are also not appropriate for Asian population

Where do we stand with ICRP60?

International Nuclear Information System (INIS)

Harding, L.K.; Thomson, W.H.

1993-01-01

We have examined the implications of ICRP60 for nuclear medicine. Radiation doses to staff are currently low and reduction of the dose limits will have little impact. However, the proposed figures for the foetus may have implications for pregnant women where the workloads are high. With nursing staff on the ward, laboratory staff or indeed departmental porters there seems little problem. Radiation dose to the fingers is, however, a key factor, and ensuring that nor further restrictions are placed on the proposed dose limits is important. The concept of constraints is becoming clearer but will need further thought, particularly with regard to exposure of the general public. The previous basis for declaring controlled and supervised areas has been abandoned, and the situation is now less clear. A most important area of debate will be the patient who is a controlled area, and great care will have to be taken to ensure that the number of patients in this category is not increased so that many more patients need to be kept in hospital. Exposure of the general public is also an issue and expanding the concept of medical exposure to include carers is an important development. This should prevent a number of unnecessary restrictions and adds weight to the point that two waiting rooms are not justified in nuclear medicine departments. ICRP recommendations will soon be incorporated into the legislation of member states and it is important for everyone to ensure that drafts are read carefully and that national proposals are not too restrictive. (orig.)

Problems encountered in embodying the principles of ICRP-26 and the revised IAEA safety standards into UK national legislation

International Nuclear Information System (INIS)

Beaver, P.F.

1979-01-01

This paper describes the United Kingdom procedures and format for safety legislation and goes on to show how the necessary legislation for radiological protection will fit into the general framework. The United Kingdom, as a member of the European Community and EURATOM, is bound to implement the Euratom Directive on radiological protection within the next few years. The latest draft of the Directive takes account of the recommendations of ICRP-26 and further, a recent draft of the revised IAEA Basic Safety Standards is a composite of both the Directive and ICRP-26. Thus, the effect of embodying the principles of the Directive is to embody the principles of ICRP-26 and the Basic Safety Standards. Some of the problems which have been met are described and in particular there is discussion of the problems arising from the incorporation of the three ICRP-26 facets of dose control, namely justification, optimization and limitation, into a legislative package. The UK system of evolving safety legislation now requires considerable participation by all the parties affected (or by their representatives). This paper indicates that the involvement of persons affected, coupled with a legislative package which consists of a hierarchy of (a) regulations; (b) codes of practice; and (c) guidance notes, will result in the fundamental principles of ICRP-26 being incorporated into UK legislation in a totally acceptable way. (author)

Implementation of the 1990 Recommendations of ICRP in the countries of the European community

International Nuclear Information System (INIS)

Stather, J.W.; Clarke, R.H.

1992-01-01

The International Commission on Radiological Protection (ICRP) has published new Recommendations in ICRP Publication 60. These 1990 Recommendations provide a System of Radiological Protection that takes account of the most recent information on the effects on health of exposure to ionizing radiation and trends in the setting of safety standards. Within the European Community the Recommendations of ICRP are implemented through a Euratom Directive which is binding on Member States and which is at present being revised by the Article 31 Group and must eventually be ratified by the Council of Ministers. It is expected that the new Directive will broadly endorse the principles of protection given in the 1990 recommendations together with the dose limits for both workers and members of the public. There are likely to be some modifications to the 1990 Recommendations that are mainly related to their practical application. As it will be some time before the Directive is incorporated in national regulations a number of Member States have taken independent initiatives. The development of dose constraints for occupational, medical and public exposure is being seen by national organizations in many countries as a significant new approach to improving standards of radiation protection. (author)

Investigating airborne low frequency GPR antenna-ground coupling through modelling

CSIR Research Space (South Africa)

Vogt, D

2013-10-01

Full Text Available . The plane of symmetry is a perfect electric conductor. The models are run using two rock materials: granite and dolerite, from the catalogue in Vogt (2000). These two materials cover the range of electrical properties expected for Karoo sediments... that is refracted into the ground away from the antenna travels along the surface at a greater velocity than the propagation in the ground, causing a propagation shape that has “ears” which are flatter than the typical spherical propagation in the earth...

ICRP-26, the recommendations on radiological protection

International Nuclear Information System (INIS)

Jun, J.S.

1983-01-01

Since the last ICRP recommendations on radiological protection was pubished in 1966 as it's publication 9, the revised edition of the recommendations had first been published in 1977, accommodating up-to-date knowledge of radiobiology and operational experiences of radiation protection built up for over a decade. In this article, the new version of the recommendations is reviewed in comparison with those of the publication 9, while the corrections and modifications made afterward are introduced together with the recent trends and responses of the experts in various countries for the pracical adoption or legislation of the recommendations. (Author)

ICRH programmes for antennas and for plasma dispersion relation

International Nuclear Information System (INIS)

Soell, M.; Springmann, E.

1984-02-01

This report describes the computer programmes used for designing the ICRH antennas at IPP. In the first part of the report the underlying physical principles are discussed on which the programmes are based. 2-D (two-dimensional) and 3-D (three-dimensional) models are used. In the second part the input and output of the programmes is described, and in the third part some results on ICRH antennas built for existing machines at IPP and antennas for machines which are in the design and construction phase are presented. In Appendix I the formulae for the 2-D model including plasma density profiles are described and an investigation of this 2-D model on folded dipol antennae is given. In Appendix II the main formulae for a computer program for the complete hot dispersion relation is given; the application of the program for an ASDEX plasma (dispersion for the fast wave and Bernstein wave) is shown. (orig.)

The new ICRP general recommendations

International Nuclear Information System (INIS)

Mason, Ch.; Kosako, T.; Kuniyoshi, H.; Kiryu, Y.; Choi, H.S.; Burns, P.A.; Pan, Z.Q.; Xia, Y.

2007-01-01

Regulatory views from Japan, South Korea, Australia, China and Indonesia were explained based on their regional context. Some issues, for example 'optimisation', 'dose constrains', 'natural radioactivity', were addressed from the viewpoint of how each country's current regulation system would adopt these new recommendations. It was noted that there would be a need for some flexibility in applying these new recommendations since different countries have different regulatory criteria and benchmarks as well different decision-making processes. It was also noted that definitions and terminologies should be given serious consideration with regard to non-English speaking countries to assure that the new ICRP recommendations are clearly understood, not misinterpreted, easily translated and finally applied in the field of radiation protection. In addition, some recent radiation protection activities, as well as views on utilisation of nuclear power in several countries were presented. (authors)

Rethinking basic concepts in ICRP's system of dose limitation

International Nuclear Information System (INIS)

Mills, W.A.; Mossman, K.L.

1991-01-01

The present criterion for radiation protection appears to be exposure reduction rather than adequate protection of health. The 1990 ICRP draft recommendations for a system of dose limitation would further implement this more restrictive criterion by implementing certain academic concepts and assumptions. These concepts and assumptions are discussed and the suggestion is made that the radiation protection community needs to carefully examine the need for the complex system proposed

A nuclear fuel cycle operator's point of view on the applicability of the new ICRP recommendations to aspects of nuclear safety

International Nuclear Information System (INIS)

Sheppard, G.T.; Berry, R.J.; Henry, P.

1991-01-01

The first section of the Paper deals with the ICRP recommendations, and makes general comments. The next two sections deal with the implications of the new recommendations on design and operation of Nuclear Fuel Cycle Facilities. The following conclusions are drawn: - The reductions in annual dose limits proposed in the new ICRP recommendations can be accommodated in the majority of modern nuclear fuel cycle facilities, and are less stringent than current design objectives. There are significant national differences between the UK and France in ability to accommodate the new ICRP recommendations on risk limitation from potential exposure situations (accidents). The French view is that it is not realistic to base the safety of industrial installations on risk limits expressed in terms of probability of deaths, while UK experience largely gained in the chemical and other industries, as well as in the nuclear industry, suggests that nuclear fuel cycle facilities will have no difficulty in demonstrating compliance with risk limits currently proposed by ICRP. It is unlikely that underground uranium mining operations, however sophisticated, will be able to operate within the new ICRP recommended dose limits

Mobile Phone Antenna Performance 2016

DEFF Research Database (Denmark)

Pedersen, Gert F.

This study investigates the antenna performance of a number of mobile phones widely used in the Nordic Countries. The study is supported by the Nordic Council of Ministers. The antenna performance of the phones is vital for the phones ability to ensure radio coverage in low signal situations....... The study is based on the mobile systems in the Nordic mobile networks and on both speech and data services. The selected phone models are among the most popular new phones at the time of this study....

Heating profiles on ICRF antenna Faraday shields

International Nuclear Information System (INIS)

Taylor, D.J.; Baity, F.W.; Hahs, C.L.; Riemer, B.W.; Ryan, P.M.; Williamson, D.E.

1991-01-01

A conceptual design for an uncooled Faraday shield for the BPX ion cyclotron resonance heating (ICRH) antenna, which should withstand the proposed long-pulse operation, has been completed. A high-heat-flux, uncooled Faraday shield has also been designed for the fast-wave current drive (FWCD) antenna on D3-D. For both components, the improved understanding of the heating profiles made it possible to design for heat fluxes that would otherwise have been too close to mechanically established limits. The analytical effort is described in detail, with emphasis on the design work for the BPX ICRH antenna conceptual design and for the replacement Faraday shield for the D3-D FWCD antenna. Results of analyses are shown, and configuration issues involved in component modeling are discussed. 3 refs., 6 figs., 2 tabs

Low-cost Antenna Positioning System Designed with Axiomatic Design

Directory of Open Access Journals (Sweden)

Timothy Foley Joseph

2017-01-01

Full Text Available The Engineering Optimization and Modeling Center at Reykjavik University has been carrying out research on antenna CAD, including the simulation-driven design of novel antenna topologies. However, simulation is not enough to validate a design: a custom RF anechoic chamber has been built to quantify antenna performance, particularly in terms of field properties such as radiation patterns. Such experiments require careful positioning of the antenna in the chamber accurately in 3-axis with a short development time, challenging material constraints, and minimal funding. Axiomatic Design Theory principles were applied to develop an automated 3-axis positioner system for a reference antenna and the antenna to be calibrated. Each axis can be individually controlled with a repeatability of 1 degree. This 3000 USD device can be fabricated using easily available components and rapid prototyping tools.

Innovative characteristics of the new dosimetric model for the human respiratory tract studied by the ICRP appointed Task Group of Committee 2

CERN Document Server

Melandri, C; Tarroni, G

1991-01-01

In 1984, the ICRP appointed a Task Group of Committee 2 to review and revise, as necessary, the current lung dosimetric model. On the basis of the knowledge acquired during the past 20 years, the Task Group's approach has been to review, in depth, the morphology and physiology of the human respiratory tract, inspirability of aerosols and regional deposition of inhaled particles as functions of aerosol size and breathing parameters, clearance of deposited materials, nature and specific sites of damage to the respiratory system caused by inhaled radioactive substances. In the proposed model, clearance from the three regions of the respiratory tract (extrathoracic ET, fast-clearing thoracic T sub f and slow-clearing thoracic T sub s , comprising lymph nodes) is described in terms of competition between the mechanical processes moving particles, which do not depend on the substances, and those of absorption into the blood, determined solely by the material. A Task Group report will also include models for calcula...

The regulatory consequences of Publication 60 of the ICRP (International Commission on Radiological Protection)

International Nuclear Information System (INIS)

Sugier, Annie

1992-01-01

The system of radiological protection recommended by the ICRP for future and existing proposed and continuing practices is based on the following general principles: justification, optimisation and limitation of exposure levels. This means that no practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the exposed individuals or to the society to offset the radiation detriment it causes. In relation to any particular source within a practice, the magnitude of individual doses, the number of people exposed, and the likelihood of incurring exposures where these are not certain to be received should all be kept as low as reasonably achievable, economic and social factors being taken into account. The exposure of individuals resulting from the combination of all the relevant practices should be subject to dose limits, or to some control of risk in the case of potential exposures. The system for radiological protection and the values of the limits associated with it, are related the state of knowledge of the effects of radiation. This explains the periodic revision of the corresponding regulatory texts. In a field of such complexity, concerned by disciplines as diverse as medicine, biology, chemistry, statistics, etc., the question naturally arises as to which authority has the capacity to determine an agreed policy. As far as the European Community is concerned, the basic standards related to radiation protection are the subject of Directives which have to be incorporated into national laws by each member state. These directives are under review taking into account explicitly the ICRP recommendations. International agencies whose mission is concerned with the effects of ionising radiation, publish also basic standards related to radiological protection which are not imposed to the participating states except when they collaborate with those bodies, and which mainly act as international references. Such norms also comply with

ALI and DAC for transuranic elements based on the metabolic data presented in ICRP publication 48

OpenAIRE

外川 織彦; 山口 勇吉; 本間 俊充

1987-01-01

最近刊行されたICRPの報告書、ICRP Publication 48にはICRP Publication 30の年摂取限度(ALI)と誘導空気中濃度(DAC)の計算に採用されたデータと比較して、いくつかの超ウラン元素について新しい代謝データが示されている。

A regulatory view on the applicability of the new ICRP recommendations to nuclear safety aspects

International Nuclear Information System (INIS)

Gonzalez Gomez, E.; Naegelin, R.; Vuorinen, A.P.U.

1991-01-01

The new ICRP recommendations will cause several changes in the radiological practice. This paper discusses these changes from the point of regulatory view of nuclear safety. To avoid adverse short-term effects, the new risk estimates should be adopted in radiation protection standards with great care. The ultimate objective of nuclear safety is to protect people environment and property against radiological hazards. Improvements in principles and practices developed by the ICRP are important in reaching the primary goal. A severe nuclear accident must be prevented in advance. Every scientific and technical means have to used; optimization is not the solution of the problem

Unidirectional Magneto-Electric Dipole Antenna for Base Station: A Review

Science.gov (United States)

Idayachandran, Govindanarayanan; Nakkeeran, Rangaswamy

2018-04-01

Unidirectional base station antenna design using Magneto-Electric Dipole (MED) has created enormous interest among the researchers due to its excellent radiation characteristics like low back radiation, symmetrical radiation at E-plane and H-plane compared to conventional patch antenna. Generally, dual polarized antennas are used to increase channel capacity and reliability of the communication systems. In order to serve the evolving mobile communication standards like long term evolution LTE and beyond, unidirectional dual polarized MED antenna are required to have broad impedance bandwidth, broad half power beamwidth, high port isolation, low cross polarization level, high front to back ratio and high gain. In this paper, the critical electrical requirements of the base station antenna and frequently used frequency bands for modern mobile communication have been presented. It is followed by brief review on broadband patch antenna and discussion on complementary antenna concepts. Finally, the performance of linearly polarized and dual polarized magneto-electric dipole antennas along with their feeding techniques are discussed and summarized. Also, design and modeling of developed MED antenna is presented.

Evaluation of the use of ICRP 60 dose conversion factors in a postclosure assessment of a deep geological disposal system

International Nuclear Information System (INIS)

Palattao, M.V.B.; Hajas, W.C.; Goodwin, B.W.

1997-05-01

An Environmental Impact Statement (EIS) of the concept for disposal of Canada's nuclear fuel waste was completed in 1994 and is currently under review by an independent Review Panel. This EIS included a postclosure assessment case study to estimate the annual effective dose equivalent in sieverts per year to members of the public; these estimates were obtained using dose conversion factors (DCFS) based on the 1977 recommendations of the International Commission on Radiation Protection (ICRP). However, in 1990 the ICRP revised these recommendations based on additional biological information and developments in radiation protection. This report describes a study of how the more recent recommendations of the ICRP would affect the results of the postclosure assessment case study presented in the EIS. The report includes a theoretical description of how DCFs are used and a comparison of results from computer simulations using the 1977 and the 1990 ICRP recommendations. In the EIS case study, which was based on the 1977 ICRP recommendations, the total dose rate to a member of the critical group is more than six orders of magnitude below the dose rate associated with the regulatory criterion for individual radiological risk. The total dose rate to 10 4 years is dominated by 129 I, with smaller contributions from 36 C1 and 14 C. If the 1990 ICRP recommendations were implemented, the total dose rate would be mostly affected by the new DCF for 129 I, and would increase by about 67%. Even with this increase, the total dose rate would still remain many orders of magnitude lower than the dose rate associated with the regulatory risk criterion. (author)

The Involvement of IRPA in the Development of ICRP and Other International Standards

International Nuclear Information System (INIS)

Webb, G.A.M.

2001-01-01

Full text: One of the main items in the IRPA constitution is to encourage the establishment and continuous review of universally acceptable radiation protection standards or recommendations through the international bodies concerned. This matter was discussed in depth at the Associate Societies Forum during the IRPA-10 Congress in Hiroshima in May 2000. A clear consensus existed among societies present that IRPA must play a larger role in the standard setting process. The mechanisms to fulfil this role have still to be elaborated but two processes have been identified. One for collecting and transmitting societies views on proposals by standards-setting bodies and another for quickly informing societies about the developments within international bodies on which IRPA acts as an observer. An example of the first was when IRPA invited its Member Societies to comment on Professor Roger Clarke's Controllable Dose proposal. The IRPA 10 Congress in May 2000 in Hiroshima provided the obvious focus for discussing the responses from the various Societies. These have been brought together in a report entitled IRPA Member Societies' Contributions to the development of new ICRP Recommendations and transmitted to ICRP by the IRPA Secretariat. The second procedure is more established as IRPA has observer status with a number of organisations including ICRP, IAEA and NEA and on interagency committees such as the Interagency Committee on Radiation Safety Standards (IACRS). (author)

GPS antenna designs

Science.gov (United States)

Laube, Samuel J. P.

1987-05-01

Application of the current GPS NAVSTAR system to civilian service requires that a right hand, circularly polarized, -160 dBW spread spectrum signal be received from an orbiting satellite, where the antenna environment is also moving. This presents a design challenge when inexpensive antennas are desired. The intent of this survey is to provide information on the antennas mentioned and to construct and test prototypes to determine whether the choice made by the industry, the quadrifilar helix, is the best. The helix antenna is currently the low cost standard for GPS. Prototype versions were constructed using 12 gauge wire and subminiature coaxial hardline. The constructed antennas were tested using a signal generator and a reference turnstile. A spectrum analyzer was used to measure the level of the received signal.

Modelling and performance assessment of an antenna-control system

Science.gov (United States)

Burrows, C. R.

1982-03-01

An assessment is made of a surveillance-radar control system designed to provide a sector-search capability and continuous control of antenna speed without unwanted torque-reaction on the supporting mast. These objectives are attained by utilizing regenerative braking, and control is exercised through Perbury CVTs. A detailed analysis of the system is given. The models derived for the Perbury CVTs supplement the qualitative data contained in earlier papers. Some results from a computer simulation are presented. Although the paper is concerned with a particular problem, the analysis of the CVTs, and the concept of using energy transfer to control large inertial loads, are of more general interest.

Safety of irradiated patients: a new publication of the ICRP and Dutch practice

International Nuclear Information System (INIS)

Engel, G.L.

1986-01-01

The ICRP publication 44 and two publications of the Dutch Health Council are mutually compared and confronted with the Dutch practice. Irradiation risks, precision and aspects of organization are considered. (G.J.P.)

Self-Resonant Electrically Small Loop Antennas for Hearing-Aids Application

DEFF Research Database (Denmark)

Zhang, Jiaying; Breinbjerg, Olav

2010-01-01

Two novel self-resonant electrically small antennas are proposed in this paper, which are designed for hearing aids applications. They are miniaturized by using the capacitive and inductive coupling mechanism between two loops, and the antenna impedance can be matched to a specific value without...... using any additional matching network and lumped components. The dimension of the proposed antenna is 0.10λ0×0.03λ0, and it is designed to be resonant at 900 MHz. Both the analytical model and numerical simulations are discussed and explained. The antenna is also fabricated and measured in an anechoic...... chamber. The measurement methods for electrically small antennas are reported....

Microwave RF antennas and circuits nonlinearity applications in engineering

CERN Document Server

Aluf, Ofer

2017-01-01

This book describes a new concept for analyzing RF/microwave circuits, which includes RF/microwave antennas. The book is unique in its emphasis on practical and innovative microwave RF engineering applications. The analysis is based on nonlinear dynamics and chaos models and shows comprehensive benefits and results. All conceptual RF microwave circuits and antennas are innovative and can be broadly implemented in engineering applications. Given the dynamics of RF microwave circuits and antennas, they are suitable for use in a broad range of applications. The book presents analytical methods for microwave RF antennas and circuit analysis, concrete examples, and geometric examples. The analysis is developed systematically, starting with basic differential equations and their bifurcations, and subsequently moving on to fixed point analysis, limit cycles and their bifurcations. Engineering applications include microwave RF circuits and antennas in a variety of topological structures, RFID ICs and antennas, micros...

The instrumentation calibration reduction program (ICRP) at Northeast Utilities

International Nuclear Information System (INIS)

Wyckoff, R.; Blanch, P.

1987-01-01

Northeast Utilities (NU) funded a project to study the feasibility of determining the state of core exit thermocouple (CET) calibration without having to have direct access to the CETs. Although the CETs were the prime focus, other safety related sensors were investigated. This paper describes presumptions and methods employed in the first phase, the feasibility study. Additionally, it describes the cost/benefit analysis which can be used by any utility to determine ICRP payback

Radiation safety concerns for pregnant or breast feeding patients. The positions of the NCRP and the ICRP

Energy Technology Data Exchange (ETDEWEB)

Meinhold, C.B. [Brookhaven National Lab., Upton, NY (United States)

1997-01-01

For many years, protecting the fetus has been a concern of the National Council on Radiation Protection and Measurements (NCRP) and the International Commission on Radiological Protection (ICRP). Early recommendations focused on the possibility of a wide variety of detrimental developmental effects while later recommendations focused on the potential for severe mental retardation and/or reduction in the intelligence quotient (I.Q.). The latest recommendations also note that the risk of cancer for the fetus is probably two to three times greater per Sv than in the adult. For all these reasons, the NCRP and the ICRP have provided guidance to physicians on taking all reasonable steps to ascertain whether any woman requiring a radiological or nuclear medicine procedure is pregnant or nursing a child. The NCRP and the ICRP also advise the clinician to postpone such procedures until after delivery or cessation of nursing, if possible.

Radiation safety concerns for pregnant or breast feeding patients. The positions of the NCRP and the ICRP

International Nuclear Information System (INIS)

Meinhold, C.B.

1997-01-01

For many years, protecting the fetus has been a concern of the National Council on Radiation Protection and Measurements (NCRP) and the International Commission on Radiological Protection (ICRP). Early recommendations focused on the possibility of a wide variety of detrimental developmental effects while later recommendations focused on the potential for severe mental retardation and/or reduction in the intelligence quotient (I.Q.). The latest recommendations also note that the risk of cancer for the fetus is probably two to three times greater per Sv than in the adult. For all these reasons, the NCRP and the ICRP have provided guidance to physicians on taking all reasonable steps to ascertain whether any woman requiring a radiological or nuclear medicine procedure is pregnant or nursing a child. The NCRP and the ICRP also advise the clinician to postpone such procedures until after delivery or cessation of nursing, if possible

Continuous zoom antenna for mobile visible light communication.

Science.gov (United States)

Zhang, Xuebin; Tang, Yi; Cui, Lu; Bai, Tingzhu

2015-11-10

In this paper, we design a continuous zoom antenna for mobile visible light communication (VLC). In the design, a right-angle reflecting prism was adopted to fold the space optical path, thus decreasing the antenna thickness. The surface of each lens in the antenna is spherical, and the system cost is relatively low. Simulation results indicated that the designed system achieved the following performance: zoom ratio of 2.44, field of view (FOV) range of 18°-48°, system gain of 16.8, and system size of 18 mm×6  mm. Finally, we established an indoor VLC system model in a room the size of 5  m ×5  m ×3  m and compared the detection results of the zoom antenna and fixed-focus antenna obtained in a multisource communication environment, a mobile VLC environment, and a multiple-input multiple-output communication environment. The simulation results indicated that the continuous zoom antenna could realize large FOV and high gain. Moreover, the system showed improved stability, mobility, and environmental applicability.

The evolution of the international system of radiological protection: stakeholder views from the 1st and 2nd NEA/ICRP fora

International Nuclear Information System (INIS)

Lazo, Ted

2003-01-01

The Nuclear Energy Agency's (NEA's) Committee on Radiological Protection and Public Health (CRPPH) has collaborated closely with the ICRP in its efforts to develop new recommendations for radiological protection at the start of the 21st century. As part of this effort, the NEA organised, in collaboration with the ICRP, two fora to discuss the radiological protection of the environment (Taormina, February 2002) and the future policy for radiological protection (Lanzarote, April 2003). Both these meetings were attended by a broad representation of stakeholders. The CRPPH and other stakeholders universally appreciated the opportunity to speak directly with the ICRP on these important subjects. This report summarises the main conclusions made during these two meetings to advance the deliberations of the ICRP to create a new set of recommendations responsive to stakeholder needs, firmly rooted in science, and that can be implemented in a timely, efficient and cost-effective manner. (memorandum)

Population specific absorption studies for some diet incorporated trace elements : comparison with ICRP data

International Nuclear Information System (INIS)

Parameswaran, M.; Dang, H.S.

1999-01-01

Daily intake and excretion can provide an important information regarding the absorption through the gastro-intestinal tract (f1 factor) of trace elements incorporated in diet. The absorption may depend upon the kind of diet consumed, the content of the fibre, protein etc and it could be quite different for two populations groups with entirely different food habits. ICRP has provided data on the intake and excretion of 63 trace elements by Caucasian population representing North American and European adults. This paper reports intake and excretion of twelve elements Na, K, Ca, Mg, Cu, Mn, Rb, Fe, Zn, Sr, Li and Cr for an urban adult Indian population group and compares with corresponding data on ICRP reference man. (author)

New Flexible Medical Compact Antenna: Design and Analysis

Directory of Open Access Journals (Sweden)

Yann Mahe

2012-01-01

Full Text Available Some results on embedded antennas for medical wireless communication systems are presented. Medical telemetry can advantageously assist medical diagnostics. For example, you can better locate a diseased area by monitoring temperature inside the human body. In order to establish efficient wireless links in such an environment, a special attention should be paid to the antenna design. It is required to be of a low profile, very small regardless of the working frequency—434 MHz in the ISM band, safe, and cost effective. Design of the as-considered antenna is proposed based on a simple model. The approach has been demonstrated for a compact flexible antenna with a factor of 10 with respect to the half-wave antenna, rolling up inside an ingestible pill. Measured and calculated impedance behaviour and radiation characteristics of the modified patch are determined. Excellent agreement was found between experiment and theory.

The translation of the new ICRP recommendations into practice: a new challenge for International Co-operation

International Nuclear Information System (INIS)

Ilari, O.; Gonzalez, A.; Boutrif, E.; Hanson, G.; Borras, C.

1992-01-01

The new ICRP recommendations have introduced several elements of novelty which may have a significant impact on the requirements and costs of radiation protection in Member countries. There is now a need for a conversion of the ICRP guidance into terms that are sufficiently practical and straightforward to facilitate their transfer into regulatory texts and operational practices at the national level. The paper discusses the strategy adopted for the revision of the Basic Safety Standards for Radiation Protection and highlights the main issues to be considered in this work.(author)

Application of the SWE-to-PWE antenna diagnostics technique to an offset reflector antenna

DEFF Research Database (Denmark)

Cappellin, Cecilia; Frandsen, Aksel; Breinbjerg, Olav

2008-01-01

Electrical and mechanical errors in an antenna may seriously affect the antenna's performance. Although their presence is usually detected by anomalies in the antenna's far-field pattern, their identification is normally possible only through an analysis of the antenna's extreme near field....... The reconstruction of the extreme near field on the basis of near- or far-field measurements is thus an essential step in antenna diagnostics....

Cellular Reflectarray Antenna

Science.gov (United States)

Romanofsky, Robert R.

2010-01-01

The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

Monostatic ultra-wideband GPR antenna for through wall detection

Directory of Open Access Journals (Sweden)

Ali Jawad

2017-01-01

Full Text Available The aim of this paper is to present a monostatic arc-shaped ultra-wideband (UWB printed monopole antenna system with 3-16 GHz frequency bandwidth suitable for through-wall detection. Ground penetrating radar (GPR technique is used for detection with the gain of 6.2 dB achieved for the proposed antenna using defected ground structure (DGS method. To serve the purpose, a simulation experiment of through-wall detection model is constructed which consists of a monostatic antenna act as transmitter and receiver, concrete wall and human skin model. The time domain reflection of obtained result is then analysed for target detection.

Effect of new ICRP guidelines on radiological protection

International Nuclear Information System (INIS)

Anon.

1992-01-01

The new limits proposed by ICRP and under consideration (at the time of writing) by AECB (Atomic Energy Control Board of Canada) reduce the maximum exposure of atomic radiation workers from 50 to 20 mSv per year, and that of the general public from 5 to 1 mSv. The new guidelines will have three main effects: first, some licensees may have difficulty in complying; secondly, many workers may have to be reclassified as atomic radiation workers; thirdly, extensive retraining will be needed. Activities affected include reactor retubing and underground uranium mining

Determination of antenna factors using a three-antenna method at open-field test site

Science.gov (United States)

Masuzawa, Hiroshi; Tejima, Teruo; Harima, Katsushige; Morikawa, Takao

1992-09-01

Recently NIST has used the three-antenna method for calibration of the antenna factor of an antenna used for EMI measurements. This method does not require the specially designed standard antennas which are necessary in the standard field method or the standard antenna method, and can be used at an open-field test site. This paper theoretically and experimentally examines the measurement errors of this method and evaluates the precision of the antenna-factor calibration. It is found that the main source of the error is the non-ideal propagation characteristics of the test site, which should therefore be measured before the calibration. The precision of the antenna-factor calibration at the test site used in these experiments, is estimated to be 0.5 dB.

Ultrasmall Dual-Band Metamaterial Antennas Based on Asymmetrical Hybrid Resonators

Directory of Open Access Journals (Sweden)

Ji-Xu Zhu

2016-01-01

Full Text Available A new type of hybrid resonant circuit model is investigated theoretically and experimentally. The resonant model consists of a right hand (RH patch part and a composite right and left handed (CRLH part (RH + CRLH, which determines a compact size and also a convenient frequency modulation characteristic for the proposed antennas. For experimental demonstration, two antennas are fabricated. The former dual-band antenna operating at f-1=3.5 GHz (Wimax and f+1=5.25 GHz (WLAN occupies an area of 0.21λ0×0.08λ0, and two dipolar radiation patterns are obtained with comparable gains of about 6.1 and 6.2 dB, respectively. The latter antenna advances in many aspects such as an ultrasmall size of only 0.16λ0×0.08λ0, versatile radiation patterns with a monopolar pattern at f0=2.4 GHz (Bluetooth, and a dipole one at f+1=3.5 GHz (Wimax and also comparable antenna gains. Circuit parameters are extracted and researched. Excellent performances of the antennas based on hybrid resonators predict promising applications in multifunction wireless communication systems.

Development of internal dosimetry protocols using the code MCNPx and voxelized phantoms of Reference of ICRP 110; Desenvolvimento de protocolos de dosimetria interna empregando o codigo MCNPx e fantomas voxelizados de referencia da ICRP 110

Energy Technology Data Exchange (ETDEWEB)

Mendes, B.M.; Fonseca, T.C.F., E-mail: bmm@cdtn.br [Centro de esenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Trindade, B.M.; Campos, T.P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

2017-04-01

The objective of this work was to perform internal dosimetry calculations for {sup 18}F-FDG employing the MCNPx code and ICRP 110 voxelized reference phantoms (RCP{sub A}F and RCP{sub A}M). The methodologies developed and validated here represent protocols of internal dosimetry holding a better anthropomorphic and anthropometric representation of the human model in which heterogeneous distributions of the emissions can be adopted, useful in the study of new radiopharmaceuticals and internal contamination cases. The reference phantoms were implemented to run on MCNPx. Biodistribution data of {sup 18}F-FDG radiopharmaceutical provided in ICRP 128 were used in the simulations. The organs average absorbed doses and the effective doses were calculated for each model. The values obtained were compared with two reference works available in the literature for validation purposes. The means of the difference of our values and Zankl et al., 2012 reference values were -0.3% for RCP{sub A}M and -0.4% for RCP{sub A}F. Considering Hadid et al., 2013 reference values, the means of the deviation were -2.9% and -2.2% for RCP{sub A}M and RCP{sub A}F respectively. No statistically significant differences were observed (p <0.01) between the reference values and the values calculated by the internal dosimetry protocols developed by our group. Considering the {sup 18}F-FDG validation study performed in this work, the internal dosimetry protocols developed by our group have produced suitable dosimetry data. (author)

A new state space model for the NASA/JPL 70-meter antenna servo controls

Science.gov (United States)

Hill, R. E.

1987-01-01

A control axis referenced model of the NASA/JPL 70-m antenna structure is combined with the dynamic equations of servo components to produce a comprehansive state variable (matrix) model of the coupled system. An interactive Fortran program for generating the linear system model and computing its salient parameters is described. Results are produced in a state variable, block diagram, and in factored transfer function forms to facilitate design and analysis by classical as well as modern control methods.

A nuclear power plant operator's view on the effects of ICRP recommendation 26 upon his radiation protection program

International Nuclear Information System (INIS)

Selleslagh, E.

1981-01-01

The effects of ICRP recommendation 26 on rules to be implemented by nuclear power plant operators in their radiation protection program, are examined from various points of view: legal and para-legal aspects such as implementation by local authorities and interference with the regulatory process, external and internal irradiation control and limitation, ALARA and cost-benefit aspects, and the record keeping and monitoring requirements. It appears that certain parts of ICRP 26 were not retained by Euratom and thus have little chance of appearing in modified European law. Nonetheless, they are applied through licensing practices. ICRP 26 itself either confirms existing practice, which was often more conservative than law, or relaxes limits, and provides a more logical context for non-whole body exposures. ALARA-rules and practices cause an additional administrative burden, but this already existed and provides useful data for the plant management. The problem of ''zero dose'' and of converting in vivo measurements to dose in case the intakes are unknown, are addressed briefly. It is concluded that ICRP 26 brings no real changes for radiation protection in nuclear power plants, except maybe some increased flexibility, and that the operators are pretty happy with it, but less so with the way it is being imposed on them. (author)

ANN Synthesis Model of Single-Feed Corner-Truncated Circularly Polarized Microstrip Antenna with an Air Gap for Wideband Applications

Directory of Open Access Journals (Sweden)

Zhongbao Wang

2014-01-01

Full Text Available A computer-aided design model based on the artificial neural network (ANN is proposed to directly obtain patch physical dimensions of the single-feed corner-truncated circularly polarized microstrip antenna (CPMA with an air gap for wideband applications. To take account of the effect of the air gap, an equivalent relative permittivity is introduced and adopted to calculate the resonant frequency and Q-factor of square microstrip antennas for obtaining the training data sets. ANN architectures using multilayered perceptrons (MLPs and radial basis function networks (RBFNs are compared. Also, six learning algorithms are used to train the MLPs for comparison. It is found that MLPs trained with the Levenberg-Marquardt (LM algorithm are better than RBFNs for the synthesis of the CPMA. An accurate model is achieved by using an MLP with three hidden layers. The model is validated by the electromagnetic simulation and measurements. It is enormously useful to antenna engineers for facilitating the design of the single-feed CPMA with an air gap.

Numerical calculation of radiation pattern of plasma channel antenna

International Nuclear Information System (INIS)

Xia Xinren; Yin Chengyou

2010-01-01

The idea of plasma channel antenna (PCA) for high power microwave weapon is presented in this paper. The radiation pattern of PCA is calculated. The directivity functions of general antenna are derived. The near electromagnetic model of PCA is created based on physical circumstances. The electromagnetic fields of PCA and surrounding air in cylindrical coordinate are given. The dispersion equation of PCA is deduced by applying the boundary conditions of electromagnetic fields. The surface wave vector of PCA is achieved. The variations of radiation characteristic with plasma density, antenna length and antenna radius are emphatically discussed. The controllability of PCA's radiation patterns is confirmed. (authors)

Low-frequency computational electromagnetics for antenna analysis

Energy Technology Data Exchange (ETDEWEB)

Miller, E.K. (Los Alamos National Lab., NM (USA)); Burke, G.J. (Lawrence Livermore National Lab., CA (USA))

1991-01-01

An overview of low-frequency, computational methods for modeling the electromagnetic characteristics of antennas is presented here. The article presents a brief analytical background, and summarizes the essential ingredients of the method of moments, for numerically solving low-frequency antenna problems. Some extensions to the basic models of perfectly conducting objects in free space are also summarized, followed by a consideration of some of the same computational issues that affect model accuracy, efficiency and utility. A variety of representative computations are then presented to illustrate various modeling aspects and capabilities that are currently available. A fairly extensive bibliography is included to suggest further reference material to the reader. 90 refs., 27 figs.

3D electromagnetic theory of ICRF multi PORT multi loop antenna

International Nuclear Information System (INIS)

Vdovin, V.L.; Kamenskij, I.V.

1997-01-01

In this report the theory of three dimensional antenna in Ion Cyclotron Resonance Frequency (ICRF) is developed for a plasma with circular magnetic surfaces. The multi loop antenna is located in ITER several ports. Circular plasma and antenna geometry provides new important tools to account for: 1) right loading antenna impedance matrix calculation urgently needed for a matching of RF generator with an antenna; 2) right calculation of an antenna toroidal and poloidal excited spectra because the DIFFRACTION, refraction and REFLECTION effects for the Fast Waves (FW) are in FIRST time are included self consistently in 3D ICRF antenna - plasma treatment; 3) right calculation of RF power deposition profiles because self consistently found 3D antenna - plasma FW excited spectra in non slab plasma model are important ones in a weakly dissipated plasma for Fast Waves (even for ITER parameters). (J.P.N.)

The evolution of the international system of radiological protection: stakeholder views from the 1st and 2nd NEA/ICRP fora

Energy Technology Data Exchange (ETDEWEB)

Lazo, Ted [OECD Nuclear Energy Agency, 12, Boulevard des Iles, 92130 Issy-les-Moulineaux (France)

2003-12-01

The Nuclear Energy Agency's (NEA's) Committee on Radiological Protection and Public Health (CRPPH) has collaborated closely with the ICRP in its efforts to develop new recommendations for radiological protection at the start of the 21st century. As part of this effort, the NEA organised, in collaboration with the ICRP, two fora to discuss the radiological protection of the environment (Taormina, February 2002) and the future policy for radiological protection (Lanzarote, April 2003). Both these meetings were attended by a broad representation of stakeholders. The CRPPH and other stakeholders universally appreciated the opportunity to speak directly with the ICRP on these important subjects. This report summarises the main conclusions made during these two meetings to advance the deliberations of the ICRP to create a new set of recommendations responsive to stakeholder needs, firmly rooted in science, and that can be implemented in a timely, efficient and cost-effective manner. (memorandum)

An efficient fringe integral equation method for optimizing the antenna location on complex bodies

DEFF Research Database (Denmark)

Jørgensen, Erik; Meincke, Peter; Breinbjerg, Olav

2001-01-01

The radiation pattern of an antenna mounted nearby, or directly on, a complex three-dimensional (3D) structure can be significantly influenced by this structure. Integral equations combined with the method of moments (MoM) provide an accurate means for calculating the scattering from the structures...... in such applications. The structure is then modelled by triangular or rectangular surface patches with corresponding surface current expansion functions. A MoM matrix which is independent of the antenna location can be obtained by modelling the antenna as an impressed electric or magnetic source, e.g., a slot antenna...... can be modelled by a magnetic Hertzian dipole. For flush-mounted antennas, or antennas mounted in close vicinity of the scattering structure, the nearby impressed source induces a highly peaked surface current on the scattering structure. For the low-order basis functions usually applied...

Influence on dose coefficients for workers of the new metabolic models

International Nuclear Information System (INIS)

Gomez Parada, I.M.; Rojo, A.M.

1998-01-01

The International Commission on Radiological Protection (ICRP) has recently reviewed the biokinetic models used in the internal contamination dose assessment. ICRP has adopted a new model for the human respiratory tract and has updated, in ICRP Publications 56, 67 and 69, some of the biokinetic models of ICRP Publication 30. In this paper, the dose coefficients for some selected radionuclides issued in ICRP Publication 68 are compared with those obtained using the software LUPED (LUng Dose Evaluation Program). The former were calculated using the new systemic models, while the latter are based on the old metabolic models. The aim is to know to what extent the new models for systematic retention influence the dose coefficients for workers. (author) [es

Photocurrent mapping of near-field optical antenna resonances

KAUST Repository

Barnard, Edward S.; Pala, Ragip A.; Brongersma, Mark L.

2011-01-01

An increasing number of photonics applications make use of nanoscale optical antennas that exhibit a strong, resonant interaction with photons of a specific frequency. The resonant properties of such antennas are conventionally characterized by far-field light-scattering techniques. However, many applications require quantitative knowledge of the near-field behaviour, and existing local field measurement techniques provide only relative, rather than absolute, data. Here, we demonstrate a photodetector platform that uses a silicon-on-insulator substrate to spectrally and spatially map the absolute values of enhanced fields near any type of optical antenna by transducing local electric fields into photocurrent. We are able to quantify the resonant optical and materials properties of nanoscale (∼50nm) and wavelength-scale (∼1μm) metallic antennas as well as high-refractive-index semiconductor antennas. The data agree well with light-scattering measurements, full-field simulations and intuitive resonator models. © 2011 Macmillan Publishers Limited. All rights reserved.

Photocurrent mapping of near-field optical antenna resonances

KAUST Repository

Barnard, Edward S.

2011-08-21

An increasing number of photonics applications make use of nanoscale optical antennas that exhibit a strong, resonant interaction with photons of a specific frequency. The resonant properties of such antennas are conventionally characterized by far-field light-scattering techniques. However, many applications require quantitative knowledge of the near-field behaviour, and existing local field measurement techniques provide only relative, rather than absolute, data. Here, we demonstrate a photodetector platform that uses a silicon-on-insulator substrate to spectrally and spatially map the absolute values of enhanced fields near any type of optical antenna by transducing local electric fields into photocurrent. We are able to quantify the resonant optical and materials properties of nanoscale (∼50nm) and wavelength-scale (∼1μm) metallic antennas as well as high-refractive-index semiconductor antennas. The data agree well with light-scattering measurements, full-field simulations and intuitive resonator models. © 2011 Macmillan Publishers Limited. All rights reserved.

The Simulation and Experiment of a Non-Cross-Feeding Printed Log-Periodic Antenna

Directory of Open Access Journals (Sweden)

Chun-Ying Kang

2015-01-01

Full Text Available A non-cross-fed printed log-periodic antenna is simulated and studied experimentally. To avoid complex feeding with long coaxial line, the non-cross-feeding structure is applied in this antenna. The software CST Microwave Studio is employed to simulate the proposed antenna, and the optimized antenna model is obtained. According to the simulation results, the antenna prototype is produced and measured. Simulation and measured results show that the antenna is with S11<-10 dB in band of 4.2–9.2 GHz. And the radiation pattern and gain vary steadily in this band, which achieves requirements for wideband antenna. This antenna design can be extended to the design of the antenna integrated in communication circuit.

The programme of work on committee 2 of ICRP on internal dosimetry

International Nuclear Information System (INIS)

Stather, J.W.

1997-01-01

Committee 2 of ICRP has the responsibility for establishing secondary standards based on the Commission's recommended dose limits. The Committee has an extensive programme of work related to internally incorporated radionuclides which was reviewed at its September, 1997 meeting in Oxford, England. It is summarized below. (author)

Structural Design of the DTU-ESA MM-Wave Validation Standard Antenna

DEFF Research Database (Denmark)

Branner, Kim; Berring, Peter; Markussen, Christen Malte

2015-01-01

A new specially designed antenna to be used for inter-comparisons and validation of antenna test facilities is under development in cooperation between DTU and TICRA under a contract from the European Space Agency. The antenna is designed to be extremely thermally and mechanically stable...... in the range of temperatures 20±5°C under arbitrary orientation in the gravity field. The antenna has a characteristic length of approximately 500mm. And in order to obtain very low measuring error, the allowable deformations of the reflector and feeds are down to 2.5μm. The antenna is modelled structurally...... is connected via a glued contact formulation in MSC.MARC. Because of the size and the complexity of the model a computer cluster is applied to solve the analyses. This paper describes the structural solution to meet these extremely strict stability requirements and the structural analyses done in order...

Multiobjective Optimization Method for Multichannel Microwave Components of Active Phased Array Antenna

Directory of Open Access Journals (Sweden)

Lu Wang

2016-01-01

Full Text Available Multichannel microwave components are widely used and the active phased array antenna is a typical representative. The high power generated from T/R modules in active phased array antenna (APAA leads to the degradation of its electrical performances, which seriously restricts the development of high-performance APAA. Therefore, to meet the demand of thermal design for APAA, a multiobjective optimization design model of cold plate is proposed. Furthermore, in order to achieve temperature uniformity and case temperature restrictions of APAA simultaneously, optimization model of channel structure is developed. Besides, an airborne active phased array antenna was tested as an example to verify the validity of the optimization model. The valuable results provide important reference for engineers to enhance thermal design technology of antennas.

Transition of radiation protection standards in ICRP recommendations and Japan's response

International Nuclear Information System (INIS)

Shirabe, Masashi

2016-01-01

Radiation protection standards are the standards set for the purpose of preventing radiation hazard and other damage. This paper confirm what the International Commission on Radiological Protection (ICRP) recommended against the standard value on public exposure in Japan's laws and regulations, and how the Japanese government responded in introducing it into Japan's laws and regulations. There were delays of 6 to 12 years for the introduction of ICRP recommendations into the laws and regulations. Compared with response to the copyright treaty, which was extremely quick with the delays of only 1 to 2 years, these delays were very large. In Japan's laws and regulations, there are no regulations on the standard value for public exposure, and introduction of the recommended standard value of 1 mSv/year from ICRP has been avoided by the government. It is supposed that the reason for not introducing radiation dose limit and dose constraint value of public exposure was due to the lobbying of electric companies. After the Fukushima Daiichi nuclear accident, the former Nuclear Safety Commission set the reference level for emergency exposure situation at 20 mSv/year. Although there is the long-term target of 1 mSv/year for existing exposure, no reference level has been set yet. Due to these delays or avoidances, the rights of people suffering from radiation exposure are restricted, while perhaps the benefits of electric companies are being protected. (A.O.)

Multi-band Monopole Antennas Loaded with Metamaterial TL

Science.gov (United States)

Song, Zhi-jie; Liang, Jian-gang

2015-05-01

A novel metamaterial transmission line (TL) by loading complementary single Archimedean spiral resonator pair (CSASRP) is investigated and used to design a set of multi-frequency monopole antennas. The particularity is that the CSASRP which features dual-shunt branches in the equivalent circuit model is directly etched in the signal strip. By smartly controlling the element parameters, three antennas are designed and one of them covering UMTS and Bluetooth bands is fabricated and measured. The antenna exhibits impedance matching better than -10 dB and normal monopolar radiation patterns at working bands of 1.9-2.22 and 2.38-2.5 GHz. Moreover, the loaded element also contributes to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. The proposed antenna is also more compact over previous designs.

Smart antennas in aerospace applications

NARCIS (Netherlands)

Verpoorte, Jaco; Schippers, Harmen; Roeloffzen, C.G.H.; Marpaung, D.A.I.

2010-01-01

The interest in Smart Antennas for aerospace applications is growing. This paper describes smart antennas which can be used on aircraft. Two aerospace applications are discussed in more detail: a phased array antenna with optical beam forming and a large vibrating phased array antenna with

Antenna for Ultrawideband Channel Sounding

DEFF Research Database (Denmark)

Zhekov, Stanislav Stefanov; Tatomirescu, Alexandru; Pedersen, Gert F.

2016-01-01

A novel compact antenna for ultrawideband channel sounding is presented. The antenna is composed of a symmetrical biconical antenna modified by adding a cylinder and a ring to each cone. A feeding coaxial cable is employed during the simulations in order to evaluate and reduce its impact on the a......A novel compact antenna for ultrawideband channel sounding is presented. The antenna is composed of a symmetrical biconical antenna modified by adding a cylinder and a ring to each cone. A feeding coaxial cable is employed during the simulations in order to evaluate and reduce its impact...

Committee 2 of the ICRP: overview of the current and future work

International Nuclear Information System (INIS)

Kaul, A.

1997-01-01

An overview of the current and future work of ICRP Committee 2 was briefly discussed, the discussion was limited to internal dosimetry. The main topics were as follows: (1) Internal dose to members of the public; (2) Internal dose to the workers; (3) Internal dose to patients using radiopharmaceuticals

One- and two-dimensional antenna arrays for microwave wireless power transfer (MWPT) systems and dual-antenna transceivers

Science.gov (United States)

Lin, Yo-Sheng; Hu, Chun-Hao; Chang, Chi-Ho; Tsao, Ping-Chang

2018-06-01

In this work, we demonstrate novel one-dimensional (1D) and two-dimensional (2D) antenna arrays for both microwave wireless power transfer (MWPT) systems and dual-antenna transceivers. The antenna array can be used as the MWPT receiving antenna of an integrated MWPT and Bluetooth (BLE) communication module (MWPT-BLE module) for smart CNC (computer numerical control) spindle incorporated with the cloud computing system SkyMars. The 2D antenna array has n rows of 1 × m 1D array, and each array is composed of multiple (m) differential feeding antenna elements. Each differential feeding antenna element is a differential feeding structure with a microstrip antenna stripe. The stripe length is shorter than one wavelength to minimise the antenna area and to prevent being excited to a high-order mode. That is, the differential feeding antenna element can suppress the even mode. The mutual coupling between the antenna elements can be suppressed, and the isolation between the receiver and the transmitter can be enhanced. An inclination angle of the main beam aligns with the broadside, and the main beam is further concentrated and shrunk at the elevation direction. Moreover, if more differential feeding antenna elements are used, antenna gain and isolation can be further enhanced. The excellent performance of the proposed antenna arrays indicates that they are suitable for both MWPT systems and dual-antenna transceivers.

EM Modeling of Far-Field Radiation Patterns for Antennas on the GMA-TT UAV

Science.gov (United States)

Mackenzie, Anne I.

2015-01-01

To optimize communication with the Generic Modular Aircraft T-Tail (GMA-TT) unmanned aerial vehicle (UAV), electromagnetic (EM) simulations have been performed to predict the performance of two antenna types on the aircraft. Simulated far-field radiation patterns tell the amount of power radiated by the antennas and the aircraft together, taking into account blockage by the aircraft as well as radiation by conducting and dielectric portions of the aircraft. With a knowledge of the polarization and distance of the two communicating antennas, e.g. one on the UAV and one on the ground, and the transmitted signal strength, a calculation may be performed to find the strength of the signal travelling from one antenna to the other and to check that the transmitted signal meets the receiver system requirements for the designated range. In order to do this, the antenna frequency and polarization must be known for each antenna, in addition to its design and location. The permittivity, permeability, and geometry of the UAV components must also be known. The full-wave method of moments solution produces the appropriate dBi radiation pattern in which the received signal strength is calculated relative to that of an isotropic radiator.

Innovative characteristics of the new dosimetric model for the human respiratory tract studied by the ICRP appointed Task Group of Committee 2

International Nuclear Information System (INIS)

Melandri, C.; Battisti, P.; Tarroni, G.

1991-02-01

In 1984, the ICRP appointed a Task Group of Committee 2 to review and revise, as necessary, the current lung dosimetric model. On the basis of the knowledge acquired during the past 20 years, the Task Group's approach has been to review, in depth, the morphology and physiology of the human respiratory tract, inspirability of aerosols and regional deposition of inhaled particles as functions of aerosol size and breathing parameters, clearance of deposited materials, nature and specific sites of damage to the respiratory system caused by inhaled radioactive substances. In the proposed model, clearance from the three regions of the respiratory tract (extrathoracic ET, fast-clearing thoracic T f and slow-clearing thoracic T s , comprising lymph nodes) is described in terms of competition between the mechanical processes moving particles, which do not depend on the substances, and those of absorption into the blood, determined solely by the material. A Task Group report will also include models for calculating radiation doses to tissues of the respiratory system following inhalation of α, β and γ emitting particulate and gaseous radionuclides. (author)

Simulating the JET ITER-like Antenna circuit

International Nuclear Information System (INIS)

Van Eester, D.; Lerche, E.; Durodie, F.; Evrard, M.; Huygen, S.; Ongena, J.; Vrancken, M.; Argouarch, A.; Blackman, T.; Jacquet, P.; Mayoral, M.-L.; Monakhov, I.; Nightingale, M.; Wooldridge, E.; Whitehurst, A.; Goulding, R. H.

2009-01-01

A set of simulation/interpretation tools based on transmission line theory and on the RF model developed by M. Vrancken has been developed to study the ITER-like Antenna (ILA) at JET. For given tuning element settings, the unique solution of the equations governing the ILA circuit requires solving a system of coupled linear equations relating the voltages and currents at the antenna straps and other key locations. This computation allows cross-checking predicted values against measured experimental ones. Further more, a minimization procedure allows improving the correspondence with the quantities measured in the circuit during shots, thus coping with unavoidable errors arising from uncertainties in the measurements or from inaccuracies in the adopted RF model. Typical applications are e.g. fine-tuning of the second-stage of the ILA circuit for increased ELM-resilience, cross-checking the calibration of the measurements throughout the circuit and predicting the antenna performance and matching conditions in new plasma scenarios.

A Low Profile Ultrawide Band Monopole Antenna for Wearable Applications

Directory of Open Access Journals (Sweden)

Srinivas Doddipalli

2017-01-01

Full Text Available A low profile pentagonal shaped monopole antenna is designed and presented for wearable applications. The main objective of this paper is to design a miniaturized ultrawide band monopole planar antenna which can work efficiently in free space but also on the surface of the human body. The impact of human tissues on antenna performance is explained using the proposed pentagonal monopole antenna. The antenna is designed with a pentagonal radiator and a matched feed line of 50 ohm and square slots are integrated on defected ground of FR4 substrate with a size of 15 mm × 25 mm to achieve ultrawide band (UWB performance in free space and human proximity. This overall design will enhance the antenna performance with wide bandwidth ranging from 2.9 GHz to 11 GHz. Specific absorption rate (SAR of the proposed antenna on dispersive phantom model is also measured to observe the exposure of electromagnetic energy on human tissues. The simulated and measured results of the proposed antenna exhibit wide bandwidth and radiation characteristics in both free space and human proximity.

Design of LTCC Based Fractal Antenna

KAUST Repository

AdbulGhaffar, Farhan

2010-09-01

The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array has been designed for the first time on Low Temperature Co-fired Ceramic (LTCC) based substrate. LTCC provides a suitable platform for the development of these antennas due to its properties of vertical stack up and embedded passives. The complete antenna concept involves integration of this fractal antenna array with a Fresnel lens antenna providing a total gain of 15dB which is appropriate for medium range radar applications. The thesis also presents a comparison between the designed fractal antenna and a conventional patch antenna outlining the advantages of fractal antenna over the later one. The fractal antenna has a bandwidth of 1.8 GHz which is 7.5% of the centre frequency (24GHz) as compared to 1.9% of the conventional patch antenna. Furthermore the fractal design exhibits a size reduction of 53% as compared to the patch antenna. In the end a sensitivity analysis is carried out for the fractal antenna design depicting the robustness of the proposed design against the typical LTCC fabrication tolerances.

Discrete complex images in modeling antennas over, below or penetrating the ground

International Nuclear Information System (INIS)

Arnautovski-Toseva, Vesna; Smokvarski, Aleksandar; Popovski, Borislav; Grcev, Leonid

2002-01-01

In this paper discrete complex images (DCI) are used to obtain approximate, efficient and fast solution of Sommerfeld integrals that appear in the analysis of vertical electric dipole (VED) in presence of air-ground half-space. The results are used to model vertical antenna above, below or penetrating the ground using the moment method technique with triangular expansion functions. Thus, the time consuming direct numerical evaluation of the Sommerfeld integrals is completely or partially avoided. (Author)

[Survival strategy of photosynthetic organisms. 1. Variability of the extent of light-harvesting pigment aggregation as a structural factor optimizing the function of oligomeric photosynthetic antenna. Model calculations].

Science.gov (United States)

Fetisova, Z G

2004-01-01

In accordance with our concept of rigorous optimization of photosynthetic machinery by a functional criterion, this series of papers continues purposeful search in natural photosynthetic units (PSU) for the basic principles of their organization that we predicted theoretically for optimal model light-harvesting systems. This approach allowed us to determine the basic principles for the organization of a PSU of any fixed size. This series of papers deals with the problem of structural optimization of light-harvesting antenna of variable size controlled in vivo by the light intensity during the growth of organisms, which accentuates the problem of antenna structure optimization because optimization requirements become more stringent as the PSU increases in size. In this work, using mathematical modeling for the functioning of natural PSUs, we have shown that the aggregation of pigments of model light-harvesting antenna, being one of universal optimizing factors, furthermore allows controlling the antenna efficiency if the extent of pigment aggregation is a variable parameter. In this case, the efficiency of antenna increases with the size of the elementary antenna aggregate, thus ensuring the high efficiency of the PSU irrespective of its size; i.e., variation in the extent of pigment aggregation controlled by the size of light-harvesting antenna is biologically expedient.

Antenna theory analysis and design

CERN Document Server

Balanis, Constantine A

2005-01-01

The discipline of antenna theory has experienced vast technological changes. In response, Constantine Balanis has updated his classic text, Antenna Theory, offering the most recent look at all the necessary topics. New material includes smart antennas and fractal antennas, along with the latest applications in wireless communications. Multimedia material on an accompanying CD presents PowerPoint viewgraphs of lecture notes, interactive review questions, Java animations and applets, and MATLAB features. Like the previous editions, Antenna Theory, Third Edition meets the needs of e

Antennas from theory to practice

CERN Document Server

Huang, Yi

2008-01-01

Practical, concise and complete reference for the basics of modern antenna design Antennas: from Theory to Practice discusses the basics of modern antenna design and theory. Developed specifically for engineers and designers who work with radio communications, radar and RF engineering, this book offers practical and hands-on treatment of antenna theory and techniques, and provides its readers the skills to analyse, design and measure various antennas. Key features: Provides thorough coverage on the basics of transmission lines, radio waves and propag

Electromagnetics of body area networks antennas, propagation, and RF systems

CERN Document Server

Werner, Douglas H

2016-01-01

The book is a comprehensive treatment of the field, covering fundamental theoretical principles and new technological advancements, state-of-the-art device design, and reviewing examples encompassing a wide range of related sub-areas. In particular, the first area focuses on the recent development of novel wearable and implantable antenna concepts and designs including metamaterial-based wearable antennas, microwave circuit integrated wearable filtering antennas, and textile and/or fabric material enabled wearable antennas. The second set of topics covers advanced wireless propagation and the associated statistical models for on-body, in-body, and off-body modes. Other sub-areas such as efficient numerical human body modeling techniques, artificial phantom synthesis and fabrication, as well as low-power RF integrated circuits and related sensor technology are also discussed. These topics have been carefully selected for their transformational impact on the next generation of body-area network systems and beyo...

Multi-antenna synthetic aperture radar

CERN Document Server

Wang, Wen-Qin

2013-01-01

Synthetic aperture radar (SAR) is a well-known remote sensing technique, but conventional single-antenna SAR is inherently limited by the minimum antenna area constraint. Although there are still technical issues to overcome, multi-antenna SAR offers many benefits, from improved system gain to increased degrees-of-freedom and system flexibility. Multi-Antenna Synthetic Aperture Radar explores the potential and challenges of using multi-antenna SAR in microwave remote sensing applications. These applications include high-resolution imaging, wide-swath remote sensing, ground moving target indica

Dual Band Planar Inverted F Antenna (PIFA with L-Shape Configuration

Directory of Open Access Journals (Sweden)

khlouf Munzer Mohamad

2017-01-01

Full Text Available One of the most used antennas in mobile devices is planar inverted F antenna (PIFA. PIFA can be design in dual band frequencies due to the coverage of the wireless service in a mobile device that requires a multiple frequencies. However, the consideration of technical operation has to be combined with an evaluation of the antenna radiation impact on the users. A procedure of PIFA work in GSM (867-960MHz and GSM (1710-1899MHz is done using CST Software. The dual band frequency response is obtained by means of an insertion of an L-shaped slot, which is use to tune the operation frequencies. The prototype of the antenna is fabricated as model by CST Software and evaluated. It is found out that the PIFA antenna has a good efficiency, bandwidth as well as produce a maximum gain for the antenna. A key and innovative research is still underway to broaden performance parameters of the antenna.

From antenna to antenna: lateral shift of olfactory memory recall by honeybees.

Science.gov (United States)

Rogers, Lesley J; Vallortigara, Giorgio

2008-06-04

Honeybees, Apis mellifera, readily learn to associate odours with sugar rewards and we show here that recall of the olfactory memory, as demonstrated by the bee extending its proboscis when presented with the trained odour, involves first the right and then the left antenna. At 1-2 hour after training using both antennae, recall is possible mainly when the bee uses its right antenna but by 6 hours after training a lateral shift has occurred and the memory can now be recalled mainly when the left antenna is in use. Long-term memory one day after training is also accessed mainly via the left antenna. This time-dependent shift from right to left antenna is also seen as side biases in responding to odour presented to the bee's left or right side. Hence, not only are the cellular events of memory formation similar in bees and vertebrate species but also the lateralized networks involved may be similar. These findings therefore seem to call for remarkable parallel evolution and suggest that the proper functioning of memory formation in a bilateral animal, either vertebrate or invertebrate, requires lateralization of processing.

From antenna to antenna: lateral shift of olfactory memory recall by honeybees.

Directory of Open Access Journals (Sweden)

Lesley J Rogers

Full Text Available Honeybees, Apis mellifera, readily learn to associate odours with sugar rewards and we show here that recall of the olfactory memory, as demonstrated by the bee extending its proboscis when presented with the trained odour, involves first the right and then the left antenna. At 1-2 hour after training using both antennae, recall is possible mainly when the bee uses its right antenna but by 6 hours after training a lateral shift has occurred and the memory can now be recalled mainly when the left antenna is in use. Long-term memory one day after training is also accessed mainly via the left antenna. This time-dependent shift from right to left antenna is also seen as side biases in responding to odour presented to the bee's left or right side. Hence, not only are the cellular events of memory formation similar in bees and vertebrate species but also the lateralized networks involved may be similar. These findings therefore seem to call for remarkable parallel evolution and suggest that the proper functioning of memory formation in a bilateral animal, either vertebrate or invertebrate, requires lateralization of processing.

An approach to the new ICRP recommendations on protection of the environment for the control of radioactive discharges

International Nuclear Information System (INIS)

Telleria, Diego

2008-01-01

Full text: For many years it has been agreed at the international level that the regulations for the control of discharges during normal operation from nuclear installation shall be based in the principles of individual dose limitation and optimization of the radiation protection focused on man. These regulations using a process of constrained optimization of protection, when properly applied to limit the discharges of radionuclides, were assumed to protect also other species than man and, within the available level of scientific knowledge, this assumption is still likely to be certain. After the International Conference on the Protection of the Environment from the Effects of Ionizing Radiation in Stockholm, 2003, many national, international, regional and non-governmental organizations have been working to develop a coherent international policy on the protection of the environment from effects attributable to exposures to ionizing radiation. One of the key issues to solve is how to include in the analysis and judgment process explicitly non-human species. Most of the organizations, particularly at the international level, have expressed their expectative in connection with the results of the work of the ICRP. In December 2007 the ICRP published its new recommendations and during 2008 key documents for the international community like the UNSCEAR document on effects of radiation on non-human biota and the ICRP publication on the approach to a framework for non-human protection using the concept of reference plants and animals could close, at least, the first chapter in this complex evolutionary process in the field of radiation protection. While some of the relevant topics for the protection of the environment from all the pollutants, like the global distribution patterns, the long term bioaccumulation effects, the relation of the individual effects regarding the communities and populations, Etc are still not fully discerned and noting that ICRP in its

Report of ICRP Task Group 80: 'radiological protection in geological disposal of long-lived solid radioactive waste'.

Science.gov (United States)

Weiss, W

2012-01-01

The report of International Commission on Radiological Protection (ICRP) Task Group 80 entitled 'Radiological protection in geological disposal of long-lived solid radioactive waste' updates and consolidates previous ICRP recommendations related to solid waste disposal (ICRP Publications 46, 77, and 81). The recommendations given in this report apply specifically to geological disposal of long-lived solid radioactive waste. The report explains how the 2007 system of radiological protection, described in ICRP Publication 103, can be applied in the context of the geological disposal of long-lived solid radioactive waste. The report is written as a self-standing document. It describes the different stages in the lifetime of a geological disposal facility, and addresses the application of relevant radiological protection principles for each stage depending on the various exposure situations that can be encountered. In particular, the crucial factor that influences application of the protection system over the different phases in the lifetime of a disposal facility is the level of oversight that is present. The level of oversight affects the capability to reduce or avoid exposures. Three main time frames have to be considered for the purpose of radiological protection: time of direct oversight when the disposal facility is being implemented and active oversight is taking place; time of indirect oversight when the disposal facility is sealed and indirect oversight is being exercised to provide additional assurance on behalf of the population; and time of no oversight when oversight is no longer exercised because memory is lost. Copyright © 2012. Published by Elsevier Ltd.

FOREGROUND MODEL AND ANTENNA CALIBRATION ERRORS IN THE MEASUREMENT OF THE SKY-AVERAGED λ21 cm SIGNAL AT z∼ 20

Energy Technology Data Exchange (ETDEWEB)

Bernardi, G. [SKA SA, 3rd Floor, The Park, Park Road, Pinelands, 7405 (South Africa); McQuinn, M. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Greenhill, L. J., E-mail: gbernardi@ska.ac.za [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2015-01-20

The most promising near-term observable of the cosmic dark age prior to widespread reionization (z ∼ 15-200) is the sky-averaged λ21 cm background arising from hydrogen in the intergalactic medium. Though an individual antenna could in principle detect the line signature, data analysis must separate foregrounds that are orders of magnitude brighter than the λ21 cm background (but that are anticipated to vary monotonically and gradually with frequency, e.g., they are considered {sup s}pectrally smooth{sup )}. Using more physically motivated models for foregrounds than in previous studies, we show that the intrinsic spectral smoothness of the foregrounds is likely not a concern, and that data analysis for an ideal antenna should be able to detect the λ21 cm signal after subtracting a ∼fifth-order polynomial in log ν. However, we find that the foreground signal is corrupted by the angular and frequency-dependent response of a real antenna. The frequency dependence complicates modeling of foregrounds commonly based on the assumption of spectral smoothness. Our calculations focus on the Large-aperture Experiment to detect the Dark Age, which combines both radiometric and interferometric measurements. We show that statistical uncertainty remaining after fitting antenna gain patterns to interferometric measurements is not anticipated to compromise extraction of the λ21 cm signal for a range of cosmological models after fitting a seventh-order polynomial to radiometric data. Our results generalize to most efforts to measure the sky-averaged spectrum.

ICRP and impairment of mental function following prenatal irradiation

International Nuclear Information System (INIS)

Mole, R.H.

1992-01-01

A brief account is given of mental retardation and intelligence testing in unirradiated human populations, without which it is not possible to judge the 1991 ICRP Recommendations relating to mental impairment. The dose-response used by ICRP (1991) for the reduction of IQ by irradiation in utero has no radiobiological basis because IQ values are derived from intelligence test scores by transforming the scale of measurement. It is also defective because it assumed that IQ is distributed normally whereas this is so only in normal school children, not in a population in general including retarded persons. There seems good evidence for a substantial threshold of dose for both reduction in IQ and increase in severe mental retardation (SMR). The four prenatally irradiated bomb survivors with SMR and intrauterine dose in the dose range 1-49 cGy were not intelligence tested, so the relation between SMR and IQ in that practically important dose range cannot be examined directly, SMR is a deterministic phenomenon, so is not expected to occur unless dose exceeds a threshold. The threshold doses for SMR based on linear dose-responses using ungrouped doses were 46 and 55 cGy DS86 intrauterine dose (Otake et al 1987). The threshold 50 cGy derived here for reduction in IQ is closely similar. Mild mental retardation has not been reported as a diagnosis in bombs survivors exposed in utero. (Author)

New ICRP recommendations and radiation safety of an NPP

International Nuclear Information System (INIS)

Janzekovic, H.

2007-01-01

In March 2007 the fundamental radiation protection recommendations used world-widely in nuclear facilities were approved by the ICRP. Implementation of radiation safety standards in an NPP is a challenging issue related to all NPP phases from planning a site and its design to its decommissioning also because if neglected it could be very difficult if not impossible to implement improvement of radiation safety later during operation or decommissioning without a substantial cost. The standards are changing with a period of 15 years which is small regarding a prolonged lifetime of many NPPs and also foreseen lifetime of new NPPs, i.e. 60 years. The new recommendations are actually an upgrading of the ICRP 60. Among other changes new sets of wR and wT are given, as well as an update of around 50 different values related to doses. Two new concepts are also tackled i.e. terrorist attacks and protection of the environment. The influence of the new recommendations on the radiation safety of NPPs can be analysed by a selection of four renewed or new concepts: types of exposure situation, dose constraints, source-related approach and safety and security. Their implementation could lead to upgrading the radiation safety of future or existing NPPs as well as of decommissioning processes. Some of the concepts were already extensively and successfully used by designers of modifications or of new NPPs, as well as by operators. (author)

Some Recent Developments of Microstrip Antenna

Directory of Open Access Journals (Sweden)

Yong Liu

2012-01-01

Full Text Available Although the microstrip antenna has been extensively studied in the past few decades as one of the standard planar antennas, it still has a huge potential for further developments. The paper suggests three areas for further research based on our previous works on microstrip antenna elements and arrays. One is exploring the variety of microstrip antenna topologies to meet the desired requirement such as ultrawide band (UWB, high gain, miniaturization, circular polarization, multipolarized, and so on. Another is to apply microstrip antenna to form composite antenna which is more potent than the individual antenna. The last is growing towards highly integration of antenna/array and feeding network or operating at relatively high frequencies, like sub-millimeter wave or terahertz (THz wave regime, by using the advanced machining techniques. To support our points of view, some examples of antennas developed in our group are presented and discussed.

Antenna subset selection at multi-antenna relay with adaptive modulation

KAUST Repository

Choi, Seyeong

2011-06-01

In this paper, we proposed several antenna selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes were based on dual-hop relaying where a relay with multiple-antenna capabilities at reception and transmission is deployed between the source and the destination nodes. We analyzed the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigated the trade-off of performance and complexity by comparing the average number of active antennas, path estimations, and signal-to-noise ratio comparisons of the different proposed schemes. Copyright © 2011 John Wiley & Sons, Ltd.

Antenna subset selection at multi-antenna relay with adaptive modulation

KAUST Repository

Choi, Seyeong; Hasna, Mazen Omar; Yang, Hongchuan; Alouini, Mohamed-Slim

2011-01-01

In this paper, we proposed several antenna selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes were based on dual-hop relaying where a relay with multiple-antenna capabilities at reception and transmission is deployed between the source and the destination nodes. We analyzed the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigated the trade-off of performance and complexity by comparing the average number of active antennas, path estimations, and signal-to-noise ratio comparisons of the different proposed schemes. Copyright © 2011 John Wiley & Sons, Ltd.

A cable-free impedance and gain measurement technique for electrically small antennas

DEFF Research Database (Denmark)

Pivnenko, Sergey; Zhang, Jiaying; Breinbjerg, Olav

2010-01-01

are represented in terms of spherical wave expansions (SWEs), and the propagation is accounted for by a transmission formula. In this paper the measurement results by the proposed technique will be presented for several AUTs, including a standard gain horn antenna, a monopole antenna, and an electrically small......Impedance and gain measurements for electrically small antennas represent a great challenge due to influences of the feeding cable. The leaking current along the cable and scattering effects are two main issues caused by the feed line. In this paper, a novel cable-free antenna impedance and gain...... measurement technique for electrically small antennas is proposed. The antenna properties are extracted by measuring the signal scattered by the antenna under test (AUT), when it is loaded with three known loads. The technique is based on a rigorous electromagnetic model where the probe and AUT...

Design of a broadband hexagonal-shaped zeroth-order resonance antenna with metamaterials

Energy Technology Data Exchange (ETDEWEB)

Woo, Dong Sik; Kim, Kang Wook; Choi, Hyun Chul [Kyungpook National University, Daegu (Korea, Republic of)

2014-11-15

A broadband hexagonal-shaped metamaterials (MTMs)-based zeroth-order resonant (ZOR) antenna was designed and fabricated. The hexagonal shape of a top patch on a mushroom structure makes not only direct-current paths between the two ends of the patch but also round-current paths along the outside of the patch, thereby widening the resonance frequency of the mushroom MTM antenna. According to the shape of the hexagon patch, the presented antenna achieved impedance bandwidth of 58.6% corresponding to ultra-wideband technology. The proposed ZOR antenna was modeled by utilizing a composite right- and left-handed (CRLH) transmission line and provided 4 to 9.3 dBi of the antenna gain with reduced size as compared to conventional microstrip antennas at Ku- to K-band frequencies.

Revised dose limits and new respiratory tract model and their implications for annual limits of intake of radioactive materials - A review of recent ICRP publications

Energy Technology Data Exchange (ETDEWEB)

Schlesinger, T; Silverman, I; Shapira, M [Israel Atomic Energy Commission, Yavne (Israel). Soreq Nuclear Research Center

1996-12-01

Ionizing radiation may cause immediate and/or delayed biological damages to the body of the exposed person and/or his/her progeny. The exposure may be caused by an external source or may arise due to internal contamination by a radioactive material. To prevent such exposure, or to reduce the probability that it will occur, national authorities and international organizations engaged in radiation safety and protection have set limits for the exposure to ionizing radiation from either source. The sensitivity of the body to ionizing radiation usually decreases with age. For this reason and due to the limited possibilities to control the exposure of the general public, different limits have been set for for occupational exposure and for the exposure of members of the public of different age groups. The general principles of these limits and guidelines for their calculations are set by the International Commission on Radiological Protection (ICRP) and published in the Annals of the ICRP. The basic philosophy of the Commission, which includes the principles of justification, optimization and dose limits, the basic radiobiological models, and the distinction between stochastic and non-stochastic effects has been presented in its publication no. 26. Based on this philosophy, the Commission issued between 1979 and 1988 a series of publications followed by annexes and addenda known as publication no. 30. This series presented models describing the metabolism of radioactive materials which enter the body by inhalation and ingestion, the transfer of such materials from the respiratory tract and the gastrointestinal tract to the blood, and from there to the body organs and the excretion of the material from the body. This series presented also values for biokinetic parameters of these systems and transfer paths, and methods for calculating limits on intake which ensure that the exposure from internal contamination will not exceed the dose limits set.

Practical implications of ICRP26 for recording and regulation of radiation exposure

International Nuclear Information System (INIS)

Ward, F.A.; Woodhouse, J.A.; Kennedy, J.W.

1982-01-01

The paper compares the system of dose limitation recommended in ICRP Publication 26 with that based upon previous ICRP Publications upon which the current United Kingdom Legislation is based. Particular attention is given to the implication of the place given to the concept of committed dose in the system of dose limitation. The present dosimetry procedures in use within British Nuclear Fuels Ltd are outlined together with their practical limitations, and attention is drawn to the particular technical problems associated with plutonium uptake assessments. A number of other practical issues are identified such as dose records and the supplementary dose information which would require recording and the need for the re-education of employees in the new control concepts. A proposal is presented for internal dose recording based initially upon environmental measurements but subject to subsequent modification by preferred assessments based upon in-vivo and urinalysis techniques. Finally an assessment and, where appropriate, suspension procedure is proposed to control long-term exposure arising from plutonium intakes based upon an averaging period of 15 years. (author)

Microwave antenna holography

Science.gov (United States)

Rochblatt, David J.; Seidel, Boris L.

1992-01-01

This microwave holography technique utilizes the Fourier transform relation between the complex far field radiation pattern of an antenna and the complex aperture field distribution. Resulting aperture phase and amplitude distribution data can be used to precisely characterize various crucial performance parameters, including panel alignment, panel shaping, subreflector position, antenna aperture illumination, directivity at various frequencies, and gravity deformation effects. The methodology of data processing presented here was successfully applied to the Deep Space Network (DSN) 34-m beam waveguide antennas. The antenna performance was improved at all operating frequencies by reducing the main reflector mechanical surface rms error to 0.43 mm. At Ka-band (32 GHz), the estimated improvement is 4.1 dB, resulting in an aperture efficiency of 52 percent. The performance improvement was verified by efficiency measurements and additional holographic measurements.

ZZ NUCDECAYCALC, Nuclear Decay Data for Radiation Dosimetry Calculation for ICRP

International Nuclear Information System (INIS)

2002-01-01

1 - Description or function: The Dosimetry Research Group (DRG) of the Health Sciences Research Division at ORNL has for several years maintained data bases of nuclear decay data for use in dosimetric calculations. The data on mean and unique energy plus intensity have been previously published, in abridged form, in Publication 38 of the International Commission on Radiological Protection (ICRP 1983). This data base was designed to address the needs in medical, environmental, and occupational radiation protection. DLC-172/NUCDECAY is required by the CCC-620/SEECAL program to calculate age-dependent specific effective energies. 2 - Methods: The unabridged data used in preparing ICRP Publication 38 are distributed in electronic form in this package. The collection consists of data on the energies and intensities of radiations emitted by the 825 radionuclides reported, although abridged, in ICRP Publication 38 plus an additional 13 radionuclides evaluated during preparation of a monograph for the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. Each collection is contained in an ASCII file (INDEXR.DAT) which is a sorted list of the radionuclides containing the decay chain information. The utility code DecayCalc extracts the decay data from the library for radionuclide(s) specified by the user. It computes the activities of radionuclides present after decay and ingrowth over a user-specified time period from 1 minute to 50 years. Decay data for any decay chain may be displayed and printed either in tabular form or graphically. DecayCalc, in a slightly modified version, will be a part of CCC-553/Rascal v3. DecayCalc is a Windows application that runs under Microsoft Windows 95 or 98, or Microsoft Windows NT 4.0 or later. The Compac Fortran 77 compiler was used to compile the code. The full source for DecayCalc is not provided but will be distributed when Rascal V3 is released

Deviations in CBERS-4 Satellite Direction Components From The Electromagnetic Disturbance of Communication Antennas

Science.gov (United States)

Heilmann, A.; Fernandes, C.

2017-10-01

The CBERS-4 is a low Earth orbit satellite, with a set of antennas S-band/UHF for communication almost omni-direcional. For the electromagnetic radiation from transmission antennas, was developed a model of electromagnetic disturbance considering the antennas theory and the laws of the conservation energy-momentum. Was propagated the orbit of the CBERS-4 satellite considering your state vector from the March 14, 2016, at 11h 14m 15.23s using the equation of motion in the form of cartesian components. From the state vector of the CBERS-4 satellite was possible to propagate the orbit for different periods, without disturbance (considering just the problem of two bodies) and with a disturbance of electromagnetic origin. The model of reaction of electromagnetic acceleration on the satellite depends on only the type of antenna. Quadrifilar and parabolic propeller antennas were considered in this paper. Using the equation of motion of the satellite based on the method of Runge-Kutta of fourth and fifth degree, the effect disturber this modeling was applied on the CBERS-4 considering the mass of satellite, characteristics of antenna, power irradiated and gain maximum of antenna. The final analysis discusses the values of components in the direction (radial, cross and normal) and the coordinates X-Y-Z considering the case disturbed to both antennas.

Design of broadband single polarized antenna

Science.gov (United States)

Shin, Phoo Kho; Aziz, Mohamad Zoinol Abidin Abd.; Ahmad, Badrul Hisham; Ramli, Mohamad Hafize Bin; Fauzi, Noor Azamiah Md; Malek, Mohd Fareq Abd

2015-05-01

In practical wireless communication application, bandwidth enhancement becomes one of the major design considerations. At the same time, circular polarized (CP) antenna received much attention for the applications of modern wireless communication system when compared to linear polarized (LP) antenna. This is because CP antenna can reduce the multipath effect. Hence, broadband antenna with operating frequency at 2.4GHz for WLAN application is proposed. The proposed antenna is done by using L-probe amendment with rectangular patch. The rectangular patch and copper ground plane is separated with 10mm air gap. This approach is used to enhance the bandwidth and the gain of the proposed antenna. The bandwidth of the designed antenna is more than 200MHz which meet broadband application. The return loss for the antenna is below -10dB to achieved 90% matching efficiency. The position of L-probe feed is altered in order to obtained different polarizations. The broadband antenna had been designed and simulated by using Computer Simulation Technology (CST) software. In this paper, the comparison for single polarized antenna with the design of non-inverted patch and inverted patch is discussed. The characteristics of the S-parameter, axial ratio, gain, surface current for each designed antenna are analyzed.

Battery-less wireless interrogation of microstrip patch antenna for strain sensing

International Nuclear Information System (INIS)

Xu, X; Huang, H

2012-01-01

This paper presents a battery-less wireless interrogation system that can measure the resonant frequency of a microstrip patch antenna with a fine resolution. Since the antenna resonant frequency is sensitive to strain-induced deformations, wireless interrogation of the antenna sensor for strain measurement was demonstrated. By implementing a microwatt impedance switching circuit at the sensor node, the antenna backscattering is amplitude modulated at the sensor node so that it can be separated from the structural backscattering at the interrogator. The sensor node can be powered by a small photocell and thus achieve battery-less operation. The operating principle of the wireless interrogation system is first described, followed by the implementation and characterization of the wireless interrogation system. The antenna resonant frequency shifts were correlated to the applied strains through a static tensile experiment. An excellent agreement between the experimental results and the analytical prediction was obtained. A power transmission model was established and validated with experimental measurements. Based on this power transmission model, we estimated that the maximum interrogation distance of the wireless strain measurement system is 26 m. (paper)

Implications of the ICRP draft recommendations for ALIs

International Nuclear Information System (INIS)

Stather, J.W.; Kendall, G.M.; Phipps, A.W.

1990-01-01

The results of the calculations summarised here suggest that under the new scheme for calculating annual limits on intake proposed by ICRP there may still be a need for an organ dose limit. This would lose one of the main advantages of the new scheme, namely that ALIs could be strictly additive. Adjusting the weighting factors and allocating the 'remainder' to possibly two tissues with the highest doses would result in effectances from different radionuclides which were not strictly additive. If, however, for practical purposes effectance could be taken to be additive, then the resulting ALIs could be apportioned between different radionuclides as desired. (author)

Traveling wave antenna for fast wave heating and current drive in tokamaks

International Nuclear Information System (INIS)

Ikezi, H.; Phelps, D.A.

1995-07-01

The traveling wave antenna for heating and current drive in the ion cyclotron range of frequencies is shown theoretically to have loading and wavenumber spectrum which are largely independent of plasma conditions. These characteristics have been demonstrated in low power experiments on the DIII-D tokamak, in which a standard four-strap antenna was converted to a traveling wave antenna through use of external coupling elements. The experiments indicate that the array maintains good impedance matching without dynamic tuning during abrupt changes in the plasma, such as during L- to H-mode transitions, edge localized mode activity, and disruptions. An analytic model was developed which exhibits the features observed in the experiments. Guidelines for the design of traveling wave antennas are derived from the validated model

Antenna Characterization for the JOLT Impulsive Radiator via Low-Voltage Measurements

Science.gov (United States)

Tyo, J. S.; Schoenberg, J. S. H.; Baum, C. E.; Prather, W. D.; Hackett, R.; Burger, J. W.; Farr, E. G.; Giri, D. V.; McLemore, D. P.

The JOLT system is a highly directive, impulse-like radiator. The antenna for JOLT is a 10-ft-diameter half-impulse radiating antenna (HIRA). JOLT was one of the first impulse radiating systems to employ a half IRA. For that reason, extensive measurements were made with a prototype, scale model HIRA in order to understand the performance of this class of antenna. In addition, a series of low-voltage antenna subsystem tests were performed with the full JOLT antenna before it was couple to the pulsed power and run at high voltage. The low-voltage measurements proved to be quite valuable, as an important manufacturing defect—a failure to mount the dish perpendicular to the ground plane—was identified and mitigated.

Measurement of electrostatically formed antennas using photogrammetry and theodolites

Science.gov (United States)

Goslee, J. W.; Hinson, W. F.; Kennefick, J. F.; Mihora, D. J.

1984-01-01

An antenna concept is presently being evaluated which has extremely low mass and high surface precision for potential depolyment from the Space Shuttle. This antenna concept derives its reflector surface quality from the application of electrostatic forces to tension and form a thin membrane into the desired concave reflector surface. The Shuttle-deployed antenna would have a diameter of 100 meters and an RMS surface smoothness of 10 to 1 mm for operation at 1 to 10 GHz. NASA Langley Research Center (LaRC) has built, and is currently testing, a subscale (1/20 scale) membrane reflector model of such an antenna. Several surface measurement systems were evaluated as part of the experimental surface measuring efforts. The surface measurement systems are addressed as well as some of the preliminary measurement results.

Design of a novel high efficiency antenna for helicon plasma sources

Science.gov (United States)

Fazelpour, S.; Chakhmachi, A.; Iraji, D.

2018-06-01

A new configuration for an antenna, which increases the absorption power and plasma density, is proposed for helicon plasma sources. The influence of the electromagnetic wave pattern symmetry on the plasma density and absorption power in a helicon plasma source with a common antenna (Nagoya) is analysed by using the standard COMSOL Multiphysics 5.3 software. In contrast to the theoretical model prediction, the electromagnetic wave does not represent a symmetric pattern for the common Nagoya antenna. In this work, a new configuration for an antenna is proposed which refines the asymmetries of the wave pattern in helicon plasma sources. The plasma parameters such as plasma density and absorption rate for a common Nagoya antenna and our proposed antenna under the same conditions are studied using simulations. In addition, the plasma density of seven operational helicon plasma source devices, having a common Nagoya antenna, is compared with the simulation results of our proposed antenna and the common Nagoya antenna. The simulation results show that the density of the plasma, which is produced by using our proposed antenna, is approximately twice in comparison to the plasma density produced by using the common Nagoya antenna. In fact, the simulation results indicate that the electric and magnetic fields symmetry of the helicon wave plays a vital role in increasing wave-particle coupling. As a result, wave-particle energy exchange and the plasma density of helicon plasma sources will be increased.

Antenna Miniaturization with MEMS Tunable Capacitors

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

2014-01-01

In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss and their characterist......In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss...

Assessment of the long-term risks of inadvertent human intrusion into a disposal vault in deep plutonic rock: reassessment using ICRP recommendations

International Nuclear Information System (INIS)

Wuschke, D.M.

1996-06-01

Canada has conducted an extensive research program on the safe disposal of nuclear fuel waste. The program has focussed on the concept of disposal in durable containers in an engineered facility or 'vault' located 500 to 1000 m deep in plutonic rock on the Canadian Shield. As part of this task, a methodology was developed to assess the long-term risk from inadvertent intrusion scenarios, and applied to a reference conceptual design of a facility for disposal of used fuel. The AECB has specified that 'the predicted radiological risk to individuals from a waste disposal facility shall not exceed 10 -6 fatal cancers and serious genetic effects in a year.' Risk is defined as the sum, of the product of the probability of the scenario, the magnitude of the resultant radiation dose, and the probability of a health effect per unit dose. The AECB also specifies that 'calculations of individual risk should be made by using the risk conversion factor of 2 x 10 -2 per sievert.' Our earlier assessment of four human intrusion scenarios showed that the estimated risk using the risk conversion factor recommended by the AECB was at least 3 orders of magnitude below the AECB risk criterion, at all times up to 10 000 a, for each of the four scenarios analysed. The AECB risk criterion and risk conversion factor are based on the recommendations of the Intemafional Commission on Radiological Protection (ICRP) in their Publication ICRP 26. More recently, in its Publication ICRP 60, the ICRP has recommended dose factors for fatal cancers that are larger than those in ICRP 26 and an increase in the risk factor for serious hereditary effects in all future generations. Another ICRP Publication, ICRP 64, states that 'For potential exposure situations, the consideration of the basic dose response used for stochastic effects must be extended into the range of high doses where deterministic effects also occur.' For the new assessments of risk we use the estimated doses and probabilities of

RF modeling of the ITER-relevant lower hybrid antenna

International Nuclear Information System (INIS)

Hillairet, J.; Ceccuzzi, S.; Belo, J.; Marfisi, L.; Artaud, J.F.; Bae, Y.S.; Berger-By, G.; Bernard, J.M.; Cara, Ph.; Cardinali, A.; Castaldo, C.; Cesario, R.; Decker, J.; Delpech, L.; Ekedahl, A.; Garcia, J.; Garibaldi, P.; Goniche, M.; Guilhem, D.; Hoang, G.T.

2011-01-01

In the frame of the EFDA task HCD-08-03-01, a 5 GHz Lower Hybrid system which should be able to deliver 20 MW CW on ITER and sustain the expected high heat fluxes has been reviewed. The design and overall dimensions of the key RF elements of the launcher and its subsystem has been updated from the 2001 design in collaboration with ITER organization. Modeling of the LH wave propagation and absorption into the plasma shows that the optimal parallel index must be chosen between 1.9 and 2.0 for the ITER steady-state scenario. The present study has been made with n || = 2.0 but can be adapted for n || = 1.9. Individual components have been studied separately giving confidence on the global RF design of the whole antenna.

Transmit antenna selection based on shadowing side information

KAUST Repository

Yilmaz, Ferkan

2011-05-01

In this paper, we propose a new transmit antenna selection scheme based on shadowing side information. In the proposed scheme, single transmit antenna which has the highest shadowing coefficient is selected. By the proposed technique, usage of the feedback channel and channel estimation complexity at the receiver can be reduced. We consider independent but not identically distributed Generalized-K composite fading model, which is a general composite fading & shadowing channel model for wireless environments. Exact closed-form outage probability, moment generating function and symbol error probability expressions are derived. In addition, theoretical performance results are validated by Monte Carlo simulations. © 2011 IEEE.

Transmit antenna selection based on shadowing side information

KAUST Repository

Yilmaz, Ferkan; Yilmaz, Ahmet Oǧuz; Alouini, Mohamed-Slim; Kucur, Oǧuz

2011-01-01

In this paper, we propose a new transmit antenna selection scheme based on shadowing side information. In the proposed scheme, single transmit antenna which has the highest shadowing coefficient is selected. By the proposed technique, usage of the feedback channel and channel estimation complexity at the receiver can be reduced. We consider independent but not identically distributed Generalized-K composite fading model, which is a general composite fading & shadowing channel model for wireless environments. Exact closed-form outage probability, moment generating function and symbol error probability expressions are derived. In addition, theoretical performance results are validated by Monte Carlo simulations. © 2011 IEEE.

Phased array antenna control

Science.gov (United States)

Doland, G. D. (Inventor)

1978-01-01

Several new and useful improvements in steering and control of phased array antennas having a small number of elements, typically on the order of 5 to 17 elements are provided. Among the improvements are increasing the number of beam steering positions, reducing the possibility of phase transients in signals received or transmitted with the antennas, and increasing control and testing capacity with respect to the antennas.

Electromagnetic reciprocity in antenna theory

CERN Document Server

Stumpf, Martin

2018-01-01

The reciprocity theorem is among the most intriguing concepts in wave field theory and has become an integral part of almost all standard textbooks on electromagnetic (EM) theory. This book makes use of the theorem to quantitatively describe EM interactions concerning general multiport antenna systems. It covers a general reciprocity-based description of antenna systems, their EM scattering properties, and further related aspects. Beginning with an introduction to the subject, Electromagnetic Reciprocity in Antenna Theory provides readers first with the basic prerequisites before offering coverage of the equivalent multiport circuit antenna representations, EM coupling between multiport antenna systems and their EM interactions with scatterers, accompanied with the corresponding EM compensation theorems.

Electrical properties of spherical dipole antennas with lossy material cores

DEFF Research Database (Denmark)

Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

2012-01-01

A spherical magnetic dipole antenna with a linear, isotropic, homogenous, passive, and lossy material core is modeled analytically, and closed form expressions are given for the internally stored magnetic and electric energies, the radiation efficiency, and radiation quality factor. This model...... and all the provided expressions are exact and valid for arbitrary core sizes, permeability, permittivity, electric and magnetic loss tangents. Arbitrary dispersion models for both permeability and permittivity can be applied. In addition, we present an investigation for an antenna of fixed electrical...

A Two Element Plasma Antenna Array

Directory of Open Access Journals (Sweden)

F. Sadeghikia

2013-10-01

Full Text Available This theoretical study presents the characteristics of plasma monopole antennas in the VHF/UHF range using finite difference time domain (FDTD simulation. Results show that more broadband characteristics can be obtained by increasing the diameter of the plasma tube and that the minor lobes diminish in intensity as diameter increases. Furthermore, the nulls are replaced by low level radiation. Since the collision frequency, which is a function of gas pressure, represents the loss mechanism of plasma, decreasing its value increases the gain and radar cross section (RCS of the antenna. Theoretical modeling shows that at higher plasma frequencies with respect to the signal frequency, the gain and radar cross section of the plasma antenna are high enough and that the impedance curves are altered as the plasma frequency varies. Using these preliminary studies, mutual impedance and gain of a broadside array of two parallel side-by-side plasma elements is presented.

Collaboration on Modeling of Ion Bernstein Wave Antenna Array and Coupling to Plasma on Tokamak Fusion Text Reactor. Final report

International Nuclear Information System (INIS)

Intrator, T.

2000-01-01

This proposal was peer reviewed and funded as a Collaboration on ''Low Phase Speed Radio Frequency Current Drive Experiments at the Tokamak Fusion Test Reactor''. The original plans we had were to carry out the collaboration proposal by including a post doctoral scientist stationed at PPPL. In response to a 60+% funding cut, all expenses were radically pruned. The post doctoral position was eliminated, and the Principal Investigator (T. Intrator) carried out the brunt of the collaboration. Visits to TFTR enabled T. Intrator to set up access to the TFTR computing network, database, and get familiar with the new antennas that were being installed in TFTR during an up to air. One unfortunate result of the budget squeeze that TFTR felt for its last year of operation was that the experiments that we specifically got funded to perform were not granted run time on TFTR., On the other hand we carried out some modeling of the electric field structure around the four strap direct launch Ion Bernstein Wave (IBW) antenna that was operated on TFTR. This turned out to be a useful exercise and shed some light on the operational characteristics of the IBW antenna and its coupling to the plasma. Because of this turn of events, the project was renamed ''Modeling of Ion Bernstein Wave Antenna Array and Coupling to Plasma on Tokamak Fusion Test Reactor''

Modern lens antennas for communications engineering

CERN Document Server

Thornton, John

2012-01-01

The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

Eliminating bias in rainfall estimates from microwave links due to antenna wetting

Science.gov (United States)

Fencl, Martin; Rieckermann, Jörg; Bareš, Vojtěch

2014-05-01

Commercial microwave links (MWLs) are point-to-point radio systems which are widely used in telecommunication systems. They operate at frequencies where the transmitted power is mainly disturbed by precipitation. Thus, signal attenuation from MWLs can be used to estimate path-averaged rain rates, which is conceptually very promising, since MWLs cover about 20 % of surface area. Unfortunately, MWL rainfall estimates are often positively biased due to additional attenuation caused by antenna wetting. To correct MWL observations a posteriori to reduce the wet antenna effect (WAE), both empirically and physically based models have been suggested. However, it is challenging to calibrate these models, because the wet antenna attenuation depends both on the MWL properties (frequency, type of antennas, shielding etc.) and different climatic factors (temperature, due point, wind velocity and direction, etc.). Instead, it seems straight forward to keep antennas dry by shielding them. In this investigation we compare the effectiveness of antenna shielding to model-based corrections to reduce the WAE. The experimental setup, located in Dübendorf-Switzerland, consisted of 1.85-km long commercial dual-polarization microwave link at 38 GHz and 5 optical disdrometers. The MWL was operated without shielding in the period from March to October 2011 and with shielding from October 2011 to July 2012. This unique experimental design made it possible to identify the attenuation due to antenna wetting, which can be computed as the difference between the measured and theoretical attenuation. The theoretical path-averaged attenuation was calculated from the path-averaged drop size distribution. During the unshielded periods, the total bias caused by WAE was 0.74 dB, which was reduced by shielding to 0.39 dB for the horizontal polarization (vertical: reduction from 0.96 dB to 0.44 dB). Interestingly, the model-based correction (Schleiss et al. 2013) was more effective because it reduced

Effect of Randomness in Element Position on Performance of Communication Array Antennas in Internet of Things

Directory of Open Access Journals (Sweden)

Congsi Wang

2018-01-01

Full Text Available As a critical component for wireless communication, active phased array antennas face the restrictions of creating effective performance with the effect of randomness in the position of the array element, which are inevitably produced in the manufacturing and operating process of antenna. A new method for efficiently and effectively evaluating the statistic performance of antenna is presented, with consideration of randomness in element position. A coupled structural-electromagnetic statistic model for array antenna is proposed from the viewpoint of electromechanical coupling. Lastly, a 12×12 planar array is illustrated to evaluate the performance of antenna with the saddle-shaped distortion and random position error. The results show that the presented model can obtain the antenna performance quickly and effectively, providing an advantageous guidance for structural design and performance optimization for array antennas in wireless application.

The principles of radio engineering and antennas. II Antennas (2nd revised and enlarged edition)

Science.gov (United States)

Belotserkovskii, G. B.

This book represents the second part of a textbook for technical schools. The characteristics and parameters of antennas are considered along with transmission lines, the theory of single dipoles and radiator systems, and the technological realization of elements and units of the antenna-feeder system, taking into account filters and multiport networks for microwave communications applications, and ferrite circulators and isolators. The first edition of this textbook was published in 1969. For the current edition, the material in the first edition has been revised, and new material has been introduced. Much attention is given to microwave antennas, including, in particular, arrays with electrical scanning characteristics. Other topics discussed are related to the general principles of antennas, the matching of the impedance of transmission lines, the elements of transmission lines, aperture-type antennas for microwaves, and the functional characteristics of antennas for ultrashort waves.

Traveling-wave antenna for fast-wave heating and current drive in tokamaks

International Nuclear Information System (INIS)

Ikezi, H.; Phelps, D.A.

1997-01-01

The travelling-wave antenna for heating and current drive in the ion cyclotron range of frequencies is shown theoretically to have loading and wavenumber spectra that are largely independent of plasma conditions. These characteristics have been demonstrated in low-power experiments on the DIII-D tokamak, in which a standard four-strap antenna was converted to a traveling-wave antenna through use of external coupling elements. The experiments indicate that the array maintains good impedance matching without dynamic tuning during abrupt changes in the plasma, such as during L- to H-mode transitions, edge-localized mode activity, and disruptions. An analytic model was developed that exhibits the features observed in the experiments. Guidelines for the design of travelling-wave antennas are derived from the validated model. 11 refs., 14 figs

Multiple Antenna Systems with Inherently Decoupled Radiators

DEFF Research Database (Denmark)

Pelosi, Mauro; Knudsen, Mikael B.; Pedersen, Gert Frølund

2012-01-01

In multiple antenna systems mutual coupling needs to be minimized. We propose an alternative novel decoupling technique, investigating several multiple antenna configurations for small handsets through measurements and numerical simulations. The influence of different novel designs on performance...... metrics such as total loss, antenna isolation and envelope correlation coefficient are investigated. By varying antenna impedance bandwidth and antenna location with respect to the handset, both Planar Inverted F Antenna (PIFA) and Inverted F Antennas (IFA) were investigated in different UMTS frequency...

Theory and design of a tunable antenna on a partially magnetized ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.

2014-03-01

For the first time, a theoretical model is presented to predict the frequency tuning of a patch antenna on a partially magnetized ferrite substrate. Both extraordinary (E) and ordinary (O) modes of the antenna are studied. The permeability tensor of the partially magnetized ferrite is calculated through the proposed theoretical model and is subsequently used to analyze the antenna\\'s performance in a microwave simulator. Prototype antennas were built, using two different bias windings, embedded in a multilayer ferrite LTCC substrate, to demonstrate E and O mode tuning. The use of embedded windings negates the requirement of bulky electromagnets, thus providing miniaturization. The concept also eliminates the demagnetization effect, thus reducing the typically required bias fields by 95%. The prototype measurements at 13 GHz demonstrate an E-mode tuning range of 10%. The proposed theoretical model has been validated by simulations and measurements. The design is highly suitable for compact, light-weight, tunable and reconfigurable microwave systems. © 1963-2012 IEEE.

A Novel Class of Reconfigurable Spherical Fermat Spiral Multi-port Antennas

Science.gov (United States)

Caratelli, D.; Yarovoy, A.; Haider, N.

Reconfigurability in antenna systems is a desired characteristic that has attracted attention in the past years. In this work, a novel class of spherical Fermat spiral multi-port antennas for next-generation wireless communications and radar applications is presented. The device modelling is carried out by using a computationally enhanced locally conformal finite-difference time-domain full-wave procedure. In this way, the circuital characteristics and radiation properties of the antennas are investigated accurately. The structure reconfigurability, in terms of frequency of operation and radiation efficiency, is technically performed by a suitable solid-state tuning circuitry adopted to properly change the feeding/loading conditions at the input ports of the antenna.

Efficiency Improvements of Antenna Optimization Using Orthogonal Fractional Experiments

Directory of Open Access Journals (Sweden)

Yen-Sheng Chen

2015-01-01

Full Text Available This paper presents an extremely efficient method for antenna design and optimization. Traditionally, antenna optimization relies on nature-inspired heuristic algorithms, which are time-consuming due to their blind-search nature. In contrast, design of experiments (DOE uses a completely different framework from heuristic algorithms, reducing the design cycle by formulating the surrogates of a design problem. However, the number of required simulations grows exponentially if a full factorial design is used. In this paper, a much more efficient technique is presented to achieve substantial time savings. By using orthogonal fractional experiments, only a small subset of the full factorial design is required, yet the resultant response surface models are still effective. The capability of orthogonal fractional experiments is demonstrated through three examples, including two tag antennas for radio-frequency identification (RFID applications and one internal antenna for long-term-evolution (LTE handheld devices. In these examples, orthogonal fractional experiments greatly improve the efficiency of DOE, thereby facilitating the antenna design with less simulation runs.

Stretchable antenna for wearable electronics

KAUST Repository

Hussain, Muhammad Mustafa

2017-04-13

Various examples are provided for stretchable antennas that can be used for applications such as wearable electronics. In one example, a stretchable antenna includes a flexible support structure including a lateral spring section having a proximal end and at a distal end; a metallic antenna disposed on at least a portion of the lateral spring section, the metallic antenna extending along the lateral spring section from the proximal end; and a metallic feed coupled to the metallic antenna at the proximal end of the lateral spring section. In another example, a method includes patterning a polymer layer disposed on a substrate to define a lateral spring section; disposing a metal layer on at least a portion of the lateral spring section, the metal layer forming an antenna extending along the portion of the lateral spring section; and releasing the polymer layer and the metal layer from the substrate.

A Compact UWB Diversity Antenna

Directory of Open Access Journals (Sweden)

Hui Zhao

2014-01-01

Full Text Available A compact printed ultrawideband (UWB diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

Design of UAVs-Based 3D Antenna Arrays for a Maximum Performance in Terms of Directivity and SLL

Directory of Open Access Journals (Sweden)

Jesus Garza

2016-01-01

Full Text Available This paper presents a design of UAVs-based 3D antenna arrays for a maximum performance in terms of directivity and side lobe level (SLL. This paper illustrates how to model the UAVs formation flight using 3D nonuniform antenna arrays. This design of 3D antenna arrays considers the optimization of the positions of the antenna elements to model the UAVs formation flight. In this case, a disk patch antenna is chosen to be used as element in each UAV. The disk patch antenna is formulated by the well-known cavity model. The synthesis process is carried out by the method of Differential Evolution for Multiobjective Optimization (DEMO. Furthermore, a comparison of the performance of 3D nonuniform antenna arrays is provided with respect to the most conventional arrays (circular, planar, linear, and the cubic for UAVs formation flight.

Import of ICRP 60 for general mining

International Nuclear Information System (INIS)

O'Riordan, M.C.

1992-01-01

Because of the ubiquity of natural, the International Commission on Radiological Protection limits the definition of occupational exposure to circumstances that can reasonably be regarded as the responsibility of management. Radon in workplaces in given as the prime example in ICRP Publication 60, the new recommendations of the Commission. But not all workplaces are to be included, and the Commission advises that agencies should identify the particular circumstances in which protection is required. It offers some guidance: spas, uranium mines, other underground mines and caves are mentioned. Few would dispute the suggestion that underground exposure to radon in general non-uranium mining may be appreciable and that the system of protection needs to be applied in the industry. Conditions in underground mining are examined in this paper. (author)

A millimeter-wave connected antenna array for 5G applications

KAUST Repository

Ikram, Muhammad; Sharawi, Mohammad S.; Shamim, Atif

2017-01-01

In this work, a beam switched antenna system based on a planar connected antenna array (CAA) is proposed at 28 GHz for 5G applications. The antenna system consists of a 4 × 4 connected slot antenna elements. It is covering frequency band from 27.4 GHz to 28.23 GHz with at least −10dB bandwidth of 830 MHz. It is modeled on a commercially available RO3003 substrate with ∊r equal to 3.3. The dimensions of the board are equal to 61×54×0.13 mm³. The proposed design is compact and low profile. A Butler matrix based feed network is used to steer the beam at different locations.

A millimeter-wave connected antenna array for 5G applications

KAUST Repository

Ikram, Muhammad

2017-10-25

In this work, a beam switched antenna system based on a planar connected antenna array (CAA) is proposed at 28 GHz for 5G applications. The antenna system consists of a 4 × 4 connected slot antenna elements. It is covering frequency band from 27.4 GHz to 28.23 GHz with at least −10dB bandwidth of 830 MHz. It is modeled on a commercially available RO3003 substrate with ∊r equal to 3.3. The dimensions of the board are equal to 61×54×0.13 mm³. The proposed design is compact and low profile. A Butler matrix based feed network is used to steer the beam at different locations.

47 CFR 73.510 - Antenna systems.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 73.510 Section 73.510... Noncommercial Educational FM Broadcast Stations § 73.510 Antenna systems. (a) All noncommercial educational... § 73.316 concerning antenna systems contained in subpart B of this part. (b) Directional antenna. No...

DEA deformed stretchable patch antenna

International Nuclear Information System (INIS)

Jiang, X-J; Jalali Mazlouman, S; Menon, C; Mahanfar, A; Vaughan, R G

2012-01-01

A stretchable patch antenna (SPA) whose frequency is tuned by a planar dielectric elastomer actuator (DEA) is presented in this paper. This mechanically reconfigurable antenna system has a configuration resembling a pre-stretched silicone belt. Part of the belt is embedded with a layer of conductive liquid metal to form the patch antenna. Part of the belt is sandwiched between conductive electrodes to form the DEA. Electrical activation of the DEA results in a contraction of the patch antenna, and as a result, in a variation of its resonance frequency. Design and fabrication steps of this system are presented. Measurement results for deformation, resonance frequency variation and efficiency of the patch antenna are also presented. (paper)

The ICRF antennas for TFTR

International Nuclear Information System (INIS)

Hoffman, D.J.; Colestock, P.L.; Gardner, W.L.; Hosea, J.C.; Nagy, A.; Stevens, J.; Swain, D.W.; Wilson, J.R.

1988-01-01

Two compact loop antennas have been designed to provide ion cyclotron resonant frequency (ICRF) heating for TFTR. The antennas can convey a total of 10 MW to accomplish core heating in either high-density or high-temperature plasmas. The near-term goal of heating TFTR plasmas and the longer-term goals of ease in handling (for remote maintenance) and high reliability (in an inaccessible tritium tokamak environment) were major considerations in the antenna designs. The compact loop configuration facilitates handling because the antennas fit completely through their ports. Conservative design and extensive testing were used to attain the reliability required for TFTR. This paper summarizes how these antennas will accomplish these goals. 5 figs, 1 tab

Wideband Tunable PIFA Antenna with Loaded Slot Structure for Mobile Handset and LTE Applications

Directory of Open Access Journals (Sweden)

I. Elfergani

2014-04-01

Full Text Available A compact planar inverted F antenna (PIFA with a tunable frequency response is presented. Tuning of the resonant frequency is realized by loading a varactor on an embedded slot of the proposed antenna structure without further optimizing other antenna geometry parameters. The antenna exhibits a wide frequency range from 1570 to 2600 MHz with a good impedance matching (S11 ≤-10 dB covering the GPS, PCS, DCS, UMTS, WLAN and LTE systems. To validate the theoretical model and design concept, the antenna prototype was fabricated and measured. The compact size of the antenna is 15mm × 8mm × 3mm, which makes this antenna a good candidate for mobile handset and wireless communication applications.

A miniaturized micro strip antenna based on sinusoidal patch geometry for implantable biomedical applications

Science.gov (United States)

Ibrahim, Omar A.; Elwi, Taha A.; Islam, Naz E.

2012-11-01

A miniaturized microstrip antenna is analyzed for implantable biomedical applications. The antenna is designed using two different commercial software packages, CST Microwave Studio and HFSS, to validate the results. The proposed design operates in the WMTS frequency band. The antenna performance is tested inside the human body, Hugo model. The antenna design is readjusted to get the desired resonant frequency. The resonant frequency, bandwidth, gain, and radiation pattern of the proposed antenna are provided in this paper. Furthermore, the effect of losses inside human body due to the fat layer is recognized.

Experiments with dipole antennas

International Nuclear Information System (INIS)

Kraftmakher, Yaakov

2009-01-01

Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a variant of the Yagi-Uda antenna is explored. The experiments are suitable as laboratory works and classroom demonstrations, and are attractive for student projects.

Group Delay of High Q Antennas

DEFF Research Database (Denmark)

Bahramzy, Pevand; Pedersen, Gert Frølund

2013-01-01

Group Delay variations versus frequency is an essential factor which can cause distortion and degradation in the signals. Usually this is an issue in wideband communication systems, such as satellite communication systems, which are used for transmitting wideband data. However, group delay can also...... become an issue, when working with high Q antennas, because of the steep phase shift over the frequency. In this paper, it is measured how large group delay variations can become, when going from a low Q antenna to a high Q antenna. The group delay of a low Q antenna is shown to be around 1.3 ns, whereas...... a high Q antenna has group delay of around 22 ns. It is due to this huge group delay variation characteristics of high Q antennas, that signal distortion might occur in the radio system with high Q antennas....

High Rate User Ka-Band Phased Array Antenna Test Results

Science.gov (United States)

Caroglanian, Armen; Perko, Kenneth; Seufert, Steve; Dod, Tom; Warshowsky, Jay; Day, John H. (Technical Monitor)

2001-01-01

The High Rate User Phased Array Antenna (HRUPAA) is a Ka-Band planar phased array designed by the Harris Corporation for the NASA Goddard Space Flight Center. The HRUPAA permits a satellite to downlink data either to a ground station or through the Tracking and Data Relay Satellite System (TDRSS). The HRUPAA is scanned electronically by ground station / user satellite command over a 120 degree cone angle. The phased array has the advantage of not imparting attitude disturbances to the user spacecraft. The 288-element transmit-only array has distributed RF amplifiers integrated behind each of the printed patch antenna elements. The array has 33 dBW EIRP and is left-hand circularly polarized. An engineering model of a partially populated array has been developed and delivered to NASA Goddard Space Flight Center. This report deals with the testing of the engineering model at the Goddard Antenna Range near-field and compact range facilities. The antenna specifications are described first, followed by the test plan and test results.

Heating profiles on ICRF antenna Faraday shields

International Nuclear Information System (INIS)

Taylor, D.J.; Baity, F.W.; Hahs, C.L. Riemer, B.W.; Ryan, D.M.; Williamson, D.E.

1992-01-01

Poor definition of the heating profiles that occur during normal operation of Faraday shields for ion cyclotron resonant frequency (ICRF) antennas has complicated the mechanical design of ICRF system components. This paper reports that at Oak Ridge National Laboratory (ORNL), Faraday shield analysis is being used in defining rf heating profiles. In recent numerical analyses of proposed hardware for the Burning Plasma Experiment (BPX) and DIII-D, rf magnetic fields at Faraday shield surfaces were calculated, providing realistic predictions of the induced skin currents flowing on the shield elements and the resulting dissipated power profile. Detailed measurements on mock-ups of the Faraday shields for DIII-D and the Tokamak Fusion Test Reactor (TFTR) confirmed the predicted magnetic field distributions. A conceptual design for an uncooled Faraday shield for the BPX ion cyclotron resonance heating (ICRH) antenna, which should withstand the proposed long-pulse operation, has been completed. The analytical effort is described in detail, with emphasis on the design work for the BPX ICRH antenna conceptual design and for the replacement Faraday shield for the DIII-D FWCD antenna. Results of analyses are shown, and configuration issues involved in component modeling are discussed

Spherical near-field antenna measurements — The most accurate antenna measurement technique

DEFF Research Database (Denmark)

Breinbjerg, Olav

2016-01-01

The spherical near-field antenna measurement technique combines several advantages and generally constitutes the most accurate technique for experimental characterization of radiation from antennas. This paper/presentation discusses these advantages, briefly reviews the early history and present...

History of Antenna Technology for Mobile Communications in Korea

Science.gov (United States)

Min, Kyeong-Sik; Park, Chul-Keun; Kang, Suk-Youb

In this paper, we discuss the development of wireless and mobile communications in Korea, current technological trends, and the future outlook on technological developments. Since the introduction of the telegraph and the telephone in September 1885, Korea's wired and wireless communications industry has consistently developed for over 100 years. Since 1984, upon the provision of the mobile telecommunications service, the industry has seen drastic qualitative and quantitative growth in terms of both technical and economic aspects, which played a crucial role in the rapid growth of the digital industry in Korea. After the era of the analog cellular service based on the Advanced Mobile Phone System (AMPS), a precursor to the modern mobile service, Korea became the world's first country to commercialize Code Division Multiple Access (CDMA) in 1996 and succeeded in commercializing CDMA 2000 lx (IMT 2000) in 2001. With further developments in the mobile communication technology, the technology for antennas also saw drastic advancements. As the mobile antennas moved from the second to the third generation, they grew from external models to very small internal models. At the same time, they evolved into highly functional and high performance multiple band and wide band antennas. Furthermore, Korea was the first country to commercialize and offer the Wireless Broadband Internet (WiBro) service in 2006. By leading the wireless communications standardization and exerting remarkable efforts in research and development, Korea is consolidating its status as an Information Technology (IT) leader in the global market. The antenna's inherent importance will be further emphasized in the near future as it satisfies the performance and structural needs of portable terminals necessary for realizing the projected establishment of the ubiquitous world. It is thought that antenna technologies will not be limited to simple concepts as previously experienced but will utilize various kinds

Multiband Patch Antenna for Femtocell Application

Directory of Open Access Journals (Sweden)

M. R. Zaman

2014-01-01

Full Text Available A microstrip patch antenna for multiple LTE (long term evaluation frequency bands for femtocell application is proposed in this paper. Distributed antenna solution (DAS has been introduced in cellular network to achieve homogenous indoor coverage. Femtocell is the latest extension to these solutions. It is a smart solution to both coverage and capacity scales. Femtocell operation in LTE band is occupied by higher frequency bands. For multiband femtocell application, miniature antenna design is quite essential. The antenna proposed here is composed of basic monopole structure with two parasitic elements at both sides of the active element. A rectangular slot is introduced at the ground plane of the proposed antenna. The antenna is designed using ElnoS HK light CCL substrate material of relative permittivity of 9.4, dielectric loss-tangent of 0.003 and thickness of 3 mm. The S11 response of the antenna is shown to have a bandwidth of 1.01 GHz starting from 1.79 GHz to 2.8 GHz. The characteristics of the antenna are analysed using Ansoft HFSS software.

Design and control of phased ICRF antenna arrays

International Nuclear Information System (INIS)

Goulding, R.H.; Baity, F.W.; Hoffman, D.J.

1993-01-01

Phased antenna arrays operating in the ion cyclotron range of frequencies (ICRF) are used to produce highly directional wave spectra, primarily for use in current drive experiments. RF current drive using phased antennas has been demonstrated in both the JET and DIII-D tokamaks, and both devices are planning to operate new four-element arrays beginning early next year. Features of antenna design that are relevant to phased operation and production of directional spectra are reviewed. Recent advances in the design of the feed circuits and the related control systems for these arrays should substantially improve their performance, by reducing the coupling seen by the matching networks and rf power supplies caused by the mutual impedance of the array elements. The feed circuit designs for the DIII-D and JET phased antenna arrays are compared. The two configurations differ significantly due to the fact that one power amplifier is used for the entire array in the former case, and one per element in the latter. The JET system uses automatic feedback control of matching, phase and amplitude of antenna currents, and the transmitter power balance. The design of this system is discussed, and a time dependent model used to predict its behavior is described

Analysis of Circularly Polarized Hemispheroidal Dielectric Resonator Antenna Phased Arrays Using the Method of Auxiliary Sources

DEFF Research Database (Denmark)

Larsen, Niels Vesterdal; Breinbjerg, Olav

2007-01-01

The method of auxiliary sources is employed to model and analyze probe-fed hemispheroidal dielectric resonator antennas and arrays. Circularly polarized antenna elements of different designs are analyzed, and impedance bandwidths of up to 14.7% are achieved. Selected element designs are subsequen......The method of auxiliary sources is employed to model and analyze probe-fed hemispheroidal dielectric resonator antennas and arrays. Circularly polarized antenna elements of different designs are analyzed, and impedance bandwidths of up to 14.7% are achieved. Selected element designs...

Mode Theory of Multi-Armed Spiral Antennas and Its Application to Electronic Warfare Antennas

Science.gov (United States)

Radway, Matthew J.

Since their invention about 55 years ago, spiral antennas have earned a reputation for providing stable impedance and far-field patterns over multi-decade frequency ranges. For the first few decades these antennas were researched for electronic warfare receiving applications, primarily in the 2-18 GHz range. This research was often done under conditions of secrecy, and often by private contractors who did not readily share their research, and now have been defunct for decades. Even so, the body of literature on the two-armed variant of these antennas is rich, often leading non-specialists to the misconception that these antennas are completely understood. Furthermore, early work was highly experimental in nature, and was conducted before modern data collection and postprocessing capabilities were widespread, which limited the range of the studies. Recent research efforts have focused on extending the application of spirals into new areas, as well as applying exotic materials to `improve' their performance and reduce their size. While interesting results have been obtained, in most instances these were incomplete, often compromising the frequency independent nature of these antennas. This thesis expands the role of the multi-armed spiral outside of its traditional niche of receive-only monopulse direction finding. As a first step, careful study of the spiral-antenna mode theory is undertaken with particular attention paid to the concepts of mode filtering and modal decomposition. A technique for reducing the modal impedance of high arm-count spirals is introduced. The insights gained through this theoretical study are first used to improve the far-field performance of the coiled-arm spiral antenna. Specifically, expanding the number of arms on a coiled arm spiral from two to four while providing proper excitation enables dramatically improved broadside axial ratio and azimuthal pattern uniformity. The multiarming technique is then applied to the design of an antenna

Ultra wideband antennas design, methodologies, and performance

CERN Document Server

Galvan-Tejada, Giselle M; Jardón Aguilar, Hildeberto

2015-01-01

Ultra Wideband Antennas: Design, Methodologies, and Performance presents the current state of the art of ultra wideband (UWB) antennas, from theory specific for these radiators to guidelines for the design of omnidirectional and directional UWB antennas. Offering a comprehensive overview of the latest UWB antenna research and development, this book:Discusses the developed theory for UWB antennas in frequency and time domainsDelivers a brief exposition of numerical methods for electromagnetics oriented to antennasDescribes solid-planar equivalen

Minimum Q Electrically Small Antennas

DEFF Research Database (Denmark)

Kim, O. S.

2012-01-01

Theoretically, the minimum radiation quality factor Q of an isolated resonance can be achieved in a spherical electrically small antenna by combining TM1m and TE1m spherical modes, provided that the stored energy in the antenna spherical volume is totally suppressed. Using closed-form expressions...... for a multiarm spherical helix antenna confirm the theoretical predictions. For example, a 4-arm spherical helix antenna with a magnetic-coated perfectly electrically conducting core (ka=0.254) exhibits the Q of 0.66 times the Chu lower bound, or 1.25 times the minimum Q....

Utilization of antenna arrays in HF systems

Directory of Open Access Journals (Sweden)

Louis Bertel

2009-06-01

Full Text Available

Different applications of radio systems are based on the implementation of antenna arrays. Classically, radio direction

finding operates with a multi channel receiving system connected to an array of receiving antennas. More

recently, MIMO architectures have been proposed to increase the capacity of radio links by the use of antenna

arrays at both the transmitter and receiver.

The first part of this paper describes some novel experimental work carried out to examine the feasibility of applying

MIMO techniques for communications within the HF radio band. A detailed correlation analysis of a variety

of different antenna array configurations is presented. The second section of the paper also deals with HF