Nuclear radiation moisture gauge calibration standard

International Nuclear Information System (INIS)

Berry, R.L.

1981-01-01

A hydrophobic standard for calibrating radiation moisture gauges is described. This standard has little or no affinity for water and accordingly will not take up or give off water under ambient conditions of fluctuating humidity in such a manner as to change the hydrogen content presented to a nuclear gauge undergoing calibration. (O.T.)

Standardization of irradiation values at the Radiation Calibration Laboratory

International Nuclear Information System (INIS)

Pham Van Dung; Hoang Van Nguyen; Phan Van Toan; Phan Dinh Sinh; Tran Thi Tuyet; Do Thi Phuong

2007-01-01

The objective of the theme is to determine dose rates around radiation facilities and sources in the NRI Radiation Calibration Laboratory. By improving equipment, calibrating a main dosemeter and carrying out experiments, the theme team received the following results: 1. The controller of a X-rays generator PY(-200 was improved. It permits to increase accuracy of radiation dose calibration up to 2-4 times; 2. The FAMER DOSEMETER 2570/1B with the ionization chamber NE 2575 C of the NRI Radiation Calibration Laboratory was calibrated at SSDL (Hanoi); 3. Dose rates at 4 positions around a high activity Co-60 source were determined; 4. Dose rates at 3 positions around a low activity Co-60 source were determined; 5. Dose rates at 3 positions around a low activity Cs-137 source were determined; 6. Dose rate at 1 position of a X-rays beam (Eaverage = 48 keV) was determined; 7. Dose rate at 1 position of a X-rays beam (Eaverage = 65 keV) was determined. (author)

Calibration of high-dose radiation facilities (Handbook)

International Nuclear Information System (INIS)

Gupta, B.L.; Bhat, R.M.

1986-01-01

In India at present several high intensity radiation sources are used. There are 135 teletheraphy machines and 65 high intensity cobalt-60 sources in the form of gamma chambers (2.5 Ci) and PANBIT (50 Ci). Several food irradiation facilities and a medical sterilization plant ISOMED are also in operation. The application of these high intensity sources involve a wide variation of dose from 10 Gy to 100 kGy. Accurate and reproducible radiation dosimetry is essential in the use of these sources. This handbook is especially compiled for calibration of high-dose radiation facilities. The first few chapters discuss such topics as interaction of radiation with matter, radiation chemistry, radiation processing, commonly used high intensity radiation sources and their special features, radiation units and dosimetry principles. In the chapters which follow, chemical dosimeters are discussed in detail. This discussion covers Fricke dosimeter, FBX dosimeter, ceric sulphate dosimeter, free radical dosimetry, coloured indicators for irrdiation verification. A final chapter is devoted to practical hints to be followed in calibration work. (author)

The calibration procedure of the radiation monitoring system installed in radiation controlled area of KOMAC

Energy Technology Data Exchange (ETDEWEB)

Park, Sung-Kyun; Min, Yi-Sub; Park, Jeong-Min; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Gyeongju (Korea, Republic of)

2016-10-15

The spaces, where these accelerators are installed, are defined as the radiation controlled area and the levels of the radiation in this area are monitored by the radiation monitoring system (RMS) to protect radiation workers and experiment users from the hazards of the ionizing radiation and the surface and air contamination tests are carried out periodically by the radiation secure team. The most of RMS instruments are installed in the accelerator building, where the 100-MeV proton linear accelerator is installed. All detectors of RMS should be calibrated every year to prove the reliability of RMS and almost all instruments for RMS was calibrated during this summer maintenance period of KOMAC this year. Almost all RMS instruments installed in KOMAC is calibrated between 2016-07-13 and 2016-08-24. As the calibration result, if the current reading value are within the 5% of the reference dose rate value, this RMS instrument can be used one more year. Otherwise, the detector of that RMS instrument should be repaired or replaced. The self-calibration certificate for each RMS instrument will be published only for the instrument to satisfy the condition.

Reference neutron radiations. Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field

International Nuclear Information System (INIS)

2000-01-01

ISO 8529 consists of the following parts, under the general title Reference neutron radiations: Part 1: Characteristics and methods of production; Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field; Part 3: Calibration of area and personal dosimeters and determination of response as a function of energy and angle of incidence. This Part 2. of ISO 8529 takes as its starting point the neutron sources described in ISO 8529-1. It specifies the procedures to be used for realizing the calibration conditions of radiation protection devices in neutron fields produced by these calibration sources, with particular emphasis on the corrections for extraneous effects (e.g., the neutrons scattered from the walls of the calibration room). In this part of ISO 8529, particular emphasis is placed on calibrations using radionuclide sources (clauses 4 to 6) due to their widespread application, with less details given on the use of accelerator and reactor sources (8.2 and 8.3). This part of ISO 8529 then leads to ISO 8529-3 which gives conversion coefficients and the general rules and procedures for calibration

Calibration of radioprotection equipment gamma radiation at the Laboratory of Ionizing Radiation Metrology - DEN/UFPE

International Nuclear Information System (INIS)

Nazario, Macilene; Khoury, Helen; Hazin, Clovis

2003-01-01

This work presents aspects of the radioprotection equipment calibration service of the Laboratory for Metrology of Ionizing Radiations (LMRI) of the DEN/UFPE related to the calibration procedures, characteristics of the radiation beam and the evaluation of equipment calibrated in the period of 2001-2002. The LMRI-DEN/UFPE is one of the four laboratories in Brazil licensed by the Brazilian Nuclear Energy Commission for the execution of calibration services on area, surface contamination and personal monitors used by industries, hospitals, universities and research institutes using radioactive sources

Calibration of radiation protection area monitoring instruments in Sudan

International Nuclear Information System (INIS)

Suliman, I.I.; Youssif, B.E.; Beineen, A.A.; Hassan, M.

2010-01-01

This article presents results of measurements for the calibration of radiation protection area monitoring instruments carried out during the period 2006-2008 at Secondary Standard Dosimetry Laboratory of Sudan. The work performed included quality assurance measurements, measurements for the dosimeter calibrations and uncertainty analysis. Calibrations were performed using 137 Cs gamma ray sources produced by OB 85 and OB 34/1 gamma calibrators producing air kerma rate that ranged from 10 μGy/h to 50 mGy/h. Area monitoring instruments were calibrated in terms of ambient dose equivalent, H*(10) derived using air kerma to ambient dose equivalent conversion coefficients. Results are presented for 78 area monitoring instruments representing most commonly used types in Sudan. Radioactive check source measurements for the reference chamber showed deviation within 1% limit. The accuracy in the beam output measurements was within 5% internationally considered as acceptable. The results highlighted the importance of radiation protection calibrations. Regulations are further need to ensure safety aspect really meet the required international standards.

Evaluation of methods to calibrate radiation survey meters

International Nuclear Information System (INIS)

Robinson, R.C.; Arbeau, N.D.

1987-04-01

Calibration requirements for radiation survey meters used in industrial radiography have been reviewed. Information obtained from a literature search, discussions with CSLD inspectors and firms performing calibrations has been considered. Based on this review a set of minimum calibration requirements was generated which, when met, will determine that the survey meter is suited for measurements described in the current AEC Regulations that apply to industrial radiography equipment. These requirements are presented in this report and may be used as guidelines for evaluating calibration methods proposed or in use in industry. 39 refs

Activities on calibration of radiation protection instruments in Indonesia

International Nuclear Information System (INIS)

Trijoko, S.

1995-01-01

As the use of the ionizing radiation emitted by radionuclides or produced by modern machines in Indonesia has increased significantly in the past two decades, the demand for radiation protection measures has also grown up very rapidly. In the mind of Indonesian people, ionizing radiation is always associated with atomic bombs. Indonesian government has set up National Atomic Energy Agency (BATAN) through the Act No. 31/1964. The BATAN has responsibility in the research and development, implementation and inspection of the safe use of ionizing radiation for peaceful purposes, and always put a great concern on radiation protection matter. The Center for Standardization and Radiation Safety Research (CSRSR) has been founded to implement research and services in the fields of radiation safety, standardization, dosimetry, radiation health, as well as the application of nuclear techniques to medicine. In order to provide the national reference in terms of radiation dosimetry and calibration, the Secondary Standard Dosimetry Laboratory was completely set up in Jakarta by 1984. As available facilities, radiation instruments and radiation sources are described. Calibration and personal monitoring services are reported. (K.I.)

Construction and operation of an improved radiation calibration facility at Brookhaven National Laboratory. Environmental assessment

International Nuclear Information System (INIS)

1994-10-01

Calibration of instruments used to detect and measure ionizing radiation has been conducted over the last 20 years at Brookhaven National Laboratory's (BNL) Radiation Calibration Facility, Building 348. Growth of research facilities, projects in progress, and more stringent Department of Energy (DOE) orders which involve exposure to nuclear radiation have placed substantial burdens on the existing radiation calibration facility. The facility currently does not meet the requirements of DOE Order 5480.4 or American National Standards Institute (ANSI) N323-1978, which establish calibration methods for portable radiation protection instruments used in the detection and measurement of levels of ionizing radiation fields or levels of radioactive surface contaminations. Failure to comply with this standard could mean instrumentation is not being calibrated to necessary levels of sensitivity. The Laboratory has also recently obtained a new neutron source and gamma beam irradiator which can not be made operational at existing facilities because of geometry and shielding inadequacies. These sources are needed to perform routine periodic calibrations of radiation detecting instruments used by scientific and technical personnel and to meet BNL's substantial increase in demand for radiation monitoring capabilities. To place these new sources into operation, it is proposed to construct an addition to the existing radiation calibration facility that would house all calibration sources and bring BNL calibration activities into compliance with DOE and ANSI standards. The purpose of this assessment is to identify potential significant environmental impacts associated with the construction and operation of an improved radiation calibration facility at BNL

Calibration of a radiation survey meter using Cs-137 gamma source

International Nuclear Information System (INIS)

Khalid, R. O.

2005-07-01

The survey instrument smartIon was calibrated at the Secondary Standard Dosimetry Laboratory, Sudan Atomic Energy Commission, in terms of kerma, free in air using Cs-137 gamma radiation. All the calibrations were performed using the reference instrument spherical ionization chamber LS-01. This reference instrument has been calibrated at the International Atomic Energy Agency, Vienna for x-rays, 137 Cs and 60 Co gamma radiation. The air kerma calibration factors for the instrument were determined as the ratio of the dose rates obtained with the reference standard chamber LS-01 and the dose rates of the instrument under calibration. The uncertainties for the survey meter smartIon and another survey meter RADOS were obtained and the results compared with the uncertainty for the reference standard chamber. Also, the values of dose rates were obtained for various angles of the incident beam, by changing the angle by which the radiation was incident on the sensitive point of the instrument.(Author)

The ENEA calibration service for ionising radiations. Part 1: Photons

International Nuclear Information System (INIS)

Monteventi, F.; Sermenghi, I.

1999-01-01

The ENEA (National Agency for New Technology, Energy and the Environment) calibration service for ionizing radiations has been active for 40 years in the secondary standard dosimetry laboratory web. It has been the first center, in 1985, to be acknowledges by the Italian calibration service (SIT) for the two quantities for photons: exposure and air kerma. Since the Institute for the Radiation Protection of ENEA has moved to the new site in Montecuccolino (Bologna, Italy) in 1995, the whole laboratory has been renovated and all irradiation rooms together with radiation source and equipment have been reorganized according to the Χ, γ, β and neutron fields metrology requirements. The aim of this report, as the first part of a report describing all facilities available at the service, is to give a detailed description of all equipment s qualified for photon fields metrology including the secondary standards and the calibration procedures performed for radiation monitoring devices and dosemeters [it

Calibration methodology for instruments utilized in X radiation beams, diagnostic level

International Nuclear Information System (INIS)

Penha, M. da; Potiens, A.; Caldas, L.V.E.

2004-01-01

Methodologies for the calibration of diagnostic radiology instruments were established at the Calibration Laboratory of IPEN. The methods may be used in the calibration procedures of survey meters used in radiation protection measurements (scattered radiation), instruments used in direct beams (attenuated and non attenuated beams) and quality control instruments. The established qualities are recommended by the international standards IEC 1267 and ISO 4037-3. Two ionization chambers were used as reference systems, one with a volume of 30 cm 3 for radiation protection measurements, and the other with a volume of 1 cm 3 for direct beam measurements. Both are traceable to the German Primary Laboratory of Physikalisch-Technische Bundesanstalt (PTB). In the case of calibration of quality control instruments, a non-invasive method using the measurement of the spectrum endpoint was established with a portable gamma and X-ray Intertechnique spectrometer system. The methods were applied to survey meters (radiation protection measurements), ionization chambers (direct beam measurements) and k Vp meters (invasive and non-invasive instruments). (Author)

Calibration methodology for instruments utilized in X radiation beams, diagnostic level

Energy Technology Data Exchange (ETDEWEB)

Penha, M. da; Potiens, A.; Caldas, L.V.E. [Instituto de Pesquisas Energeticas e Nucleares, Comissao Nacional de Energia Nuclear, Sao Paulo (Brazil)]. E-mail: mppalbu@ipen.br

2004-07-01

Methodologies for the calibration of diagnostic radiology instruments were established at the Calibration Laboratory of IPEN. The methods may be used in the calibration procedures of survey meters used in radiation protection measurements (scattered radiation), instruments used in direct beams (attenuated and non attenuated beams) and quality control instruments. The established qualities are recommended by the international standards IEC 1267 and ISO 4037-3. Two ionization chambers were used as reference systems, one with a volume of 30 cm{sup 3} for radiation protection measurements, and the other with a volume of 1 cm{sup 3} for direct beam measurements. Both are traceable to the German Primary Laboratory of Physikalisch-Technische Bundesanstalt (PTB). In the case of calibration of quality control instruments, a non-invasive method using the measurement of the spectrum endpoint was established with a portable gamma and X-ray Intertechnique spectrometer system. The methods were applied to survey meters (radiation protection measurements), ionization chambers (direct beam measurements) and k Vp meters (invasive and non-invasive instruments). (Author)

Design and development of semi-automatic radiation test and calibration facility

International Nuclear Information System (INIS)

Yadav, Ashok Kumar; Chouhan, V.K.; Narayan, Pradeep

2008-01-01

Semi-automatic gamma radiation test and calibration facility have been designed, developed and commissioned at Defence Laboratory Jodhpur (DLJ). The facility comprises of medium and high dose rate range setup using 30 Ci Cobalt-60 source, in a portable remotely operated Techops camera and a 15000 Ci 60 Co source in a Tele-therapy machine. The radiation instruments can be positioned at any desired position using a computer controlled positioner having three translational and one rotational motion. User friendly software helps in positioning the Device Under Test (DUT) at any desired dose rate or distance and acquire the data automatically. The servo and stepper motor controlled positioner helps in achieving the required precision and accuracy for the radiation calibration of the instruments. This paper describes the semi-automatic radiation test and calibration facility commissioned at DLJ. (author)

Calibration technique for radiation measurements in vacuum ultraviolet - soft x-ray region

International Nuclear Information System (INIS)

Mizui, Jun-ichi

1986-05-01

This is a collection of the papers presented at the workshop on ''Calibration Technique for Radiation Measurements in Vacuum Ultraviolet - Soft X-ray Region'' held at the Institute of Plasma Physics, Nagoya University, on December 19 - 20, 1985, under the Collaborating Research Program at the Institute. The following topics were discussed at the workshop: the needs for the calibration of plasma diagnostic devices, present status of the calibration technique, use of the Synchrotron Orbit Radiations for radiometry, and others. (author)

Calibration of ratemeters used for gamma radiation detection

International Nuclear Information System (INIS)

Hantanirina, P.A.

2017-01-01

The Secondary Standard Dosimetry Laboratory (SSDL) of INSTN-Madagascar is in charge of the calibration of every dosimetry measurement instrument in hospitals and companies using radioactive sources in Madagascar. It has a secondary standard delivered and calibrated by a Primary Standard Laboratory in Dosimetry (PSLD). This standard is used to compare its reference values with those displayed on the instruments to be calibrated. During our training period, three (3) ratemeters were calibrated, the Graetz X5DE, the Graetz X5C and the Identifinder 2. We have determined the calibration factor for every ratemeter by doing calculation with the reference value. By using the three surveymeters for direct radiations measurements, it has been found that the difference between the displayed values and the real values for every ratemeter does not exceed the tolerance limit which is 20 %. Then we can conclude that these ratemeters are still in good condition of functioning. Concerning the calibration factor curve N_k with the K_a_i_r , we can observe that for the Graetz X5C ratemeter, this curve is almost constant. As well as for the linearity, it is still the Graetz X5C ratemeter which is linear almost integrally for the measured and calculated dose rate values. So we can say that this ratemeter is the most recommended for the radiations measurements.This work which has been carried within the framework of collaboration between the section PNAE (Physique Nucléaire Appliquée et Environnement) of the University of Antananarivo and INSTN-Madagascar has been a good and rewarding experience which allowed us to put into practice all knowledges acquired during our years of studies. [fr

Broadband Outdoor Radiometer Calibration Process for the Atmospheric Radiation Measurement Program

Energy Technology Data Exchange (ETDEWEB)

Dooraghi, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2015-09-01

The Atmospheric Radiation Measurement program (ARM) maintains a fleet of monitoring stations to aid in the improved scientific understanding of the basic physics related to radiative feedback processes in the atmosphere, particularly the interactions among clouds and aerosols. ARM obtains continuous measurements and conducts field campaigns to provide data products that aid in the improvement and further development of climate models. All of the measurement campaigns include a suite of solar measurements. The Solar Radiation Research Laboratory at the National Renewable Energy Laboratory supports ARM's full suite of stations in a number of ways, including troubleshooting issues that arise as part of the data-quality reviews; managing engineering changes to the standard setup; and providing calibration services and assistance to the full fleet of solar-related instruments, including pyranometers, pyrgeometers, pyrheliometers, as well as the temperature/relative humidity probes, multimeters, and data acquisition systems that are used in the calibrations performed at the Southern Great Plains Radiometer Calibration Facility. This paper discusses all aspects related to the support provided to the calibration of the instruments in the solar monitoring fleet.

Calibration of the ATLAS Transition Radiation Tracker

CERN Document Server

The ATLAS collaboration

2011-01-01

The Transition Radiation Tracker (TRT) is the outermost charged particle tracking device of the ATLAS Inner Detector. The TRT has about 300,000 straws, each of which is a proportional drift tube with a diameter of 4 mm. For a precise measurement of the trajectory of a charged particle (track), the relation between the measured time of the start of the signal and the distance of closest approach between the track and the anode wire needs to be calibrated. In this note, we present the calibration of the TRT detector during the first year of 7 TeV collision data-taking.

Review of radiation sources, calibration facilities and simulated workplace fields

Energy Technology Data Exchange (ETDEWEB)

Lacoste, V., E-mail: veronique.lacoste@irsn.f [Institut de Radioprotection et de Surete Nucleaire, BP3, Bat. 159, F-13115 Saint-Paul Lez Durance (France)

2010-12-15

A review on radiation sources, calibration facilities and realistic fields is presented and examples are given. The main characteristics of the fields are shortly described together with their domain of applications. New emerging fields are also mentioned and the question of needs for additional calibration fields is raised.

Determination of alternative conditions for instruments calibration with beta radiation

International Nuclear Information System (INIS)

Rocha, F.D.G.; Caldas, L.V.E.

1992-01-01

The influence of homogenization filter in the determination of chamber calibration factors and transmission factors of beta radiation in air, for obtaining different alternative conditions for beta-gamma portable monitors calibration was studied, using an extrapolation chamber and the beta secondary system at IPEN-CNEN-Brazil. (C.G.C.)

Reliability of an x-ray system for calibrating and testing personal radiation dosimeters

Science.gov (United States)

Guimarães, M. C.; Silva, C. R. E.; Rosado, P. H. G.; Cunha, P. G.; Da Silva, T. A.

2018-03-01

Metrology laboratories are expected to maintain standardized radiation beams and traceable standard dosimeters to provide reliable calibrations or testing of detectors. Results of the characterization of an x-ray system for performing calibration and testing of radiation dosimeters used for individual monitoring are shown in this work.

Research on the method of establishing the total radiation meter calibration device

Science.gov (United States)

Gao, Jianqiang; Xia, Ming; Xia, Junwen; Zhang, Dong

2015-10-01

Pyranometer is an instrument used to measure the solar radiation, according to pyranometer differs as installation state, can be respectively measured total solar radiation, reflected radiation, or with the help of shading device for measuring scattering radiation. Pyranometer uses the principle of thermoelectric effect, inductive element adopts winding plating type multi junction thermopile, its surface is coated with black coating with high absorption rate. Hot junction in the induction surface, while the cold junction is located in the body, the cold and hot junction produce thermoelectric potential. In the linear range, the output signal is proportional to the solar irradiance. Traceability to national meteorological station, as the unit of the national legal metrology organizations, the responsibility is to transfer value of the sun and the earth radiation value about the national meteorological industry. Using the method of comparison, with indoor calibration of solar simulator, at the same location, standard pyranometer and measured pyranometer were alternately measured radiation irradiance, depending on the irradiation sensitivity standard pyranometer were calculated the radiation sensitivity of measured pyranometer. This paper is mainly about the design and calibration method of the pyranometer indoor device. The uncertainty of the calibration result is also evaluated.

Calibration and application of medical particle accelerators to space radiation experiments

International Nuclear Information System (INIS)

Ryu, Kwangsun; Park, Miyoung; Chae, Jangsoo; Yoon, Sangpil; Shin, Dongho

2012-01-01

In this paper, we introduce radioisotope facilities and medical particle accelerators that can be applied to space radiation experiments and the experimental conditions required by the space radiation experiments. Space radiation experiments on the ground are critical in determining the lifetimes of satellites and in choosing or preparing the appropriate electrical parts to assure the designated mission lifetime. Before the completion of building the 100-MeV proton linear accelerator in Gyeongju, or even after the completion, the currently existing proton accelerators for medical purposes could suggest an alternative plan. We have performed experiments to calibrate medical proton beam accelerators to investigate whether the beam conditions are suitable for applications to space radiation experiments. Based on the calibration results, we propose reference beam operation conditions for space radiation experiments.

Method of calibration for portable detectors of ionizing radiation

International Nuclear Information System (INIS)

Leal, Carlos; Carrizales, Lila; Guacaran, Douglas; Moreno, Ailed; Duran, Jose

2008-01-01

Full text: The LSCD is beginning a process of accreditation by the national authority of Venezuela (CENCAMER), so we felt the need to modify existing protocols calibration, suggested by the IAEA (Technical Reports Series No 133) to be adjusted in accordance with international standards of ISO 17025 EA-4/02 and Mexican standard NOM-021-NUCL-2002, adapting the calibration procedure of portable radiation detectors to those standards. The procedure used in the LSCD, conducts an intercomparison between measures between the standard reference and to calibrate the instrument, thus verifying the correct operation of the equipment and its usefulness to the individual or environmental radiation monitoring, not to exceed the limits primary for the public and occupationally Staff Exposed (POE), and propose a simple way to perform this calibration procedure and comply with the standard international and national standards, ensuring the proper functioning of the instruments calibrated. One of the calculations that has proven to be a useful tool in the verification of the conditions of operating the same, it is uncertainty, this procedure allows to characterize the response of individual detector, depending on the constraints specified by the manufacturer, to optimize the calibration is necessary to consider the multiple factors that can affect the measure and evaluate the response of the same, so it is vitally important estimating the typical uncertainty associated with the calibration technique employed, but this calculation is not trivial, depends on the type of detector found usually between 5% to 20%, both in uncertainty as the linearity, which are the parameters that are set to consider an instrument in good or bad condition. Typical are calibrated are: monitors air Geiger-Muller, Ionization cameras, detector of Neutron's, Proportional Counter, Personal dosimeters. (author)

Reliability of an x-ray system for calibrating and testing personal radiation dosimeters

Energy Technology Data Exchange (ETDEWEB)

Guimarães, M.C.; Silva, C.R.E.; Silva, T.A. da [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Rosado, P.H.G.; Cunha, P.G. [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

Metrology laboratories are expected to maintain standardized radiation beams and traceable standard dosimeters to provide reliable calibrations or testing of detectors. Results of the characterization of an x-ray system for performing calibration and testing of radiation dosimeters used for individual monitoring are shown in this work. (author)

Reliability of an x-ray system for calibrating and testing personal radiation dosimeters

International Nuclear Information System (INIS)

Guimarães, M.C.; Silva, C.R.E.; Silva, T.A. da; Rosado, P.H.G.; Cunha, P.G.

2017-01-01

Metrology laboratories are expected to maintain standardized radiation beams and traceable standard dosimeters to provide reliable calibrations or testing of detectors. Results of the characterization of an x-ray system for performing calibration and testing of radiation dosimeters used for individual monitoring are shown in this work. (author)

Radiation condition in computerized tomography (CT): determination and calibration of dosemeters

International Nuclear Information System (INIS)

Adrade, L.C.; Peixoto, J.G.P.

2016-01-01

RQT is the standard for radiation conditions in computed tomography . It simulates a beam unrelieved of a CT scanner . The camera pencil ionization dosimeter is used in CT. The LNMRI become known characterization of RQT radiation conditions and the secondary standard calibration for type pencil ionisation chambers in its lab. The obtained beam has the characteristics required by IEC 61267. The results of the calibration presented combined uncertainty expanded to 95.45% from 2.22% . (author)

Effective radiation attenuation calibration for breast density: compression thickness influences and correction

Directory of Open Access Journals (Sweden)

Thomas Jerry A

2010-11-01

Full Text Available Abstract Background Calibrating mammograms to produce a standardized breast density measurement for breast cancer risk analysis requires an accurate spatial measure of the compressed breast thickness. Thickness inaccuracies due to the nominal system readout value and compression paddle orientation induce unacceptable errors in the calibration. Method A thickness correction was developed and evaluated using a fully specified two-component surrogate breast model. A previously developed calibration approach based on effective radiation attenuation coefficient measurements was used in the analysis. Water and oil were used to construct phantoms to replicate the deformable properties of the breast. Phantoms consisting of measured proportions of water and oil were used to estimate calibration errors without correction, evaluate the thickness correction, and investigate the reproducibility of the various calibration representations under compression thickness variations. Results The average thickness uncertainty due to compression paddle warp was characterized to within 0.5 mm. The relative calibration error was reduced to 7% from 48-68% with the correction. The normalized effective radiation attenuation coefficient (planar representation was reproducible under intra-sample compression thickness variations compared with calibrated volume measures. Conclusion Incorporating this thickness correction into the rigid breast tissue equivalent calibration method should improve the calibration accuracy of mammograms for risk assessments using the reproducible planar calibration measure.

Development and implementation of an automated system for antiquated of the process of gamma radiation monitors calibration; Desenvolvimento e implantacao de um sistema automatizado para adequacao do processo de calibracao de monitores de radiacao gama

Energy Technology Data Exchange (ETDEWEB)

Silva Junior, Iremar Alves

2012-07-01

In this study it was carried out the development and implementation of a system for the appropriate process of gamma radiation monitors calibration, constituted by a pneumatic dispositive to exchange the attenuators and a positioning table, both actuated through a control panel. We also implemented a System of Caesa-Gammatron Irradiator, which increased the range of the air kerma rates, due to its higher activity comparing with the current system of gamma radiation in use in the calibration laboratory of gamma irradiation. Hence, it was necessary the installation of an attenuator dispositive remotely controlled in this irradiator system. Lastly, it was carried out an evaluation of the reduction in the rates of the occupational dose. This dissertation was developed with the aim of improving the quality of the services of calibration and tests of gamma radiation monitors - provided by the IPEN Laboratory of Instrument Calibration - as well as decreasing the occupational dose of the technicians involved in the process of calibration, following thus the principles of radiation protection. (author)

Practice for characterization and performance of a high-dose radiation dosimetry calibration laboratory

International Nuclear Information System (INIS)

2003-01-01

This practice addresses the specific requirements for laboratories engaged in dosimetry calibrations involving ionizing radiation, namely, gamma-radiation, electron beams or X-radiation (bremsstrahlung) beams. It specifically describes the requirements for the characterization and performance criteria to be met by a high-dose radiation dosimetry calibration laboratory. The absorbed-dose range is typically between 10 and 10 5 Gy. This practice addresses criteria for laboratories seeking accreditation for performing high-dose dosimetry calibrations, and is a supplement to the general requirements described in ISO/IEC 17025. By meeting these criteria and those in ISO/IEC 17025, the laboratory may be accredited by a recognized accreditation organization. Adherence to these criteria will help to ensure high standards of performance and instill confidence regarding the competency of the accredited laboratory with respect to the services it offers

Variable transformation of calibration equations for radiation dosimetry

International Nuclear Information System (INIS)

Watanabe, Yoichi

2005-01-01

For radiation dosimetry, dosimetric equipment must be calibrated by using known doses. The calibration is done to determine an equation that relates the absorbed dose to a physically measurable quantity. Since the calibration equation is accompanied by unavoidable uncertainties, the doses estimated with such equations suffer from inherent uncertainties. We presented mathematical formulation of the calibration when the calibration relation is either linear or nonlinear. We also derived equations for the uncertainty of the estimated dose as a function of the uncertainties of the parameters in the equations and the measured physical quantity. We showed that a dosimeter with a linear calibration equation with zero dose-offset enables us to perform relative dosimetry without calibration data. Furthermore, a linear equation justifies useful data manipulations such as rescaling the dose and changing the dose-offset for comparing dose distributions. Considering that some dosimeters exhibit linear response with a large dose-offset or often nonlinear response, we proposed variable transformations of the measured physical quantity, namely, linear- and log-transformation methods. The proposed methods were tested with Kodak X-Omat V radiographic film and BANG (registered) polymer gel dosimeter. We demonstrated that the variable transformation methods could lead to linear equations with zero dose-offset and could reduce the uncertainty of the estimated dose

An alternative method for calibration of narrow band radiometer using a radiative transfer model

Energy Technology Data Exchange (ETDEWEB)

Salvador, J; Wolfram, E; D' Elia, R [Centro de Investigaciones en Laseres y Aplicaciones, CEILAP (CITEFA-CONICET), Juan B. de La Salle 4397 (B1603ALO), Villa Martelli, Buenos Aires (Argentina); Zamorano, F; Casiccia, C [Laboratorio de Ozono y Radiacion UV, Universidad de Magallanes, Punta Arenas (Chile) (Chile); Rosales, A [Universidad Nacional de la Patagonia San Juan Bosco, UNPSJB, Facultad de Ingenieria, Trelew (Argentina) (Argentina); Quel, E, E-mail: jsalvador@citefa.gov.ar [Universidad Nacional de la Patagonia Austral, Unidad Academica Rio Gallegos Avda. Lisandro de la Torre 1070 ciudad de Rio Gallegos-Sta Cruz (Argentina) (Argentina)

2011-01-01

The continual monitoring of solar UV radiation is one of the major objectives proposed by many atmosphere research groups. The purpose of this task is to determine the status and degree of progress over time of the anthropogenic composition perturbation of the atmosphere. Such changes affect the intensity of the UV solar radiation transmitted through the atmosphere that then interacts with living organisms and all materials, causing serious consequences in terms of human health and durability of materials that interact with this radiation. One of the many challenges that need to be faced to perform these measurements correctly is the maintenance of periodic calibrations of these instruments. Otherwise, damage caused by the UV radiation received will render any one calibration useless after the passage of some time. This requirement makes the usage of these instruments unattractive, and the lack of frequent calibration may lead to the loss of large amounts of acquired data. Motivated by this need to maintain calibration or, at least, know the degree of stability of instrumental behavior, we have developed a calibration methodology that uses the potential of radiative transfer models to model solar radiation with 5% accuracy or better relative to actual conditions. Voltage values in each radiometer channel involved in the calibration process are carefully selected from clear sky data. Thus, tables are constructed with voltage values corresponding to various atmospheric conditions for a given solar zenith angle. Then we model with a radiative transfer model using the same conditions as for the measurements to assemble sets of values for each zenith angle. The ratio of each group (measured and modeled) allows us to calculate the calibration coefficient value as a function of zenith angle as well as the cosine response presented by the radiometer. The calibration results obtained by this method were compared with those obtained with a Brewer MKIII SN 80 located in the

Guide for selection and calibration of dosimetry systems for radiation processing

International Nuclear Information System (INIS)

2002-01-01

This guide covers the basis for selecting and calibrating dosimetry systems used to measure absorbed dose in gamma ray or X-ray fields and in electron beams used for radiation processing. It discusses the types of dosimetry systems that may be employed during calibration or on a routine basis as part of quality assurance in commercial radiation processing of products. This guide also discusses interpretation of absorbed dose and briefly outlines measurements of the uncertainties associated with the dosimetry. The details of the calibration of the analytical instrumentation are addressed in individual dosimetry system standard practices. The absorbed-dose range covered is up to 1 MGy (100 Mrad). Source energies covered are from 0.1 to 50 MeV photons and electrons. This guide should be used along with standard practices and guides for specific dosimetry systems and applications covered in other standards. Dosimetry for radiation processing with neutrons or heavy charged particles is not covered in this guide

Some methods for calibration and beta radiation dosimetry

International Nuclear Information System (INIS)

Caldas, Linda V. Ehlin

1980-01-01

The calibration of beta radiation was studied from the point of view of primary and secondary standardization, using extrapolation chambers and examining several effects. The properties of a commercial ionization chamber were investigated, and the possibility of its use in calibration and dosimetry of 90 Sr- 90 Y beta radiation was demonstrated . A secondary standard calibration facility was developed and the results obtained with this facility were compared with those obtained from a primary system directly or indirectly. Nearly energy independent response was obtained in.the range 60 keV to 0,8 MeV with this secondary standard. Two solid state techniques namely thermoluminescence (TL) and thermally stimulated exoelectron emission (TSEE) were also used for beta dosimetry. Various characteristics like reproducibility, response with dose,energy dependence, etc. were studied for the materials: LiF, CaF 2 ,Li 2 B 4 O 7 , Be O, CaSO 4 and Al 2 O 3 . TL detectors of thickness 0,9 mm underestimate the dose 60 μm thick CaSO 4 :Tm embedded on a thin aluminium plate gave energy independent response behind skin layers of 7 mg/cm 2 . Mixed field of beta, X and gamma radiation was analysed using this detector. Quartz based Be O and graphite based alpha beta-Al 2 O 3 were found to be good beta radiation detectors when the TSEE technique is used. Energy independent CaSO 4 :Tm TL dosimeters were used in international comparison for dose measurements and the results obtained were in agreement with the actual given doses within 10%. The TL detectors were also used for dose rate measurements from glazed painted tiles used in construction industry and a 85 Kr source used in textile and metal industries. Results obtained in the later case were Q compared with those using the secondary standard facility. (author)

Calibration for radiation protection survey meter SSM1

International Nuclear Information System (INIS)

Jin Hua.

1992-03-01

The calibration functions for the Radiation Protection Survey Meter SSM1 built-in Geiger Mueller measuring tubes of the type ZP 1201 (low dose rate tube) and ZP 1313 (high dose rate tube) are given in the present study. Six dose rate points are proposed as the calibration points of covering the range from 500 nSv/h up to 5 Sv/h. The difference between the true dose rate and the values calculated with the method in this paper for No. 382 SSM1 is less than ±2%. (author)

Guidelines for the Calibration of Routine Dosimetry Systems for use in Radiation Processing

DEFF Research Database (Denmark)

Sharpe, Peter; Miller, Arne

A set of guidelines has been developed to assist in the calibration of routine dosimetry systems for use in industrial radiation processing plants. Topics covered include the calibration of equipment, the performance of calibration irradiations and the derivation of mathematical functions...

Ten years of a National Service of Dosimetric calibration at radiation protection

International Nuclear Information System (INIS)

Morales, J.A.; Jova, L.; Hernandez, E.; Campa, R.; Walwyn, G.

1996-01-01

Since 1986, the CPHR has offered a national service of calibration of dosimetric instruments at levels of radiation protection. The history of such a service is the chronology of efforts to reduce the uncertainties of the calibration process, expand the ranges of useful dose rates, and enhance the radiological safety when using the sources. The crowning of those efforts is the complement and start-up of the secondary la laboratory of dosimetric calibration (SLDC), which is currently a member of the IAEA/WHO. SLDC international network. As a result of this service, 256 instruments have been calibration and 867 personal dosimeters film badges and TLD and 72 environmental TLD dosimeters have been irradiated at known doses. The service rendered has benefited 62 national institutions which are users of ionizing radiations

Report on radiation protection calibration activities in Australia

International Nuclear Information System (INIS)

Hargrave, N.J.

1995-01-01

Australia is a federation of eight autonomous States or Territories. Each of these is responsible for many matters including radiation safety within their borders. National matters are the responsibility of the Federal Government. The Australian Radiation Laboratory (ARL) is a part of the Federal Government Department of Human Services and Health and undertakes research and service activities related to radiation health. Work related to both ionising and non ionising radiation and regulatory matters is performed. Some of the research activities relate to radiation measurement standards, environmental radioactivity (e.g. radon in air, radioactivity in drinking water), effects of electro-magnetic fields on health (ELF), ultra violet radiation (UV) and laser safety, radiochemistry, medical applications of radiation (and doses to the population as a result), general health physics, thermoluminescent dosimetry (TLD) and electron spin resonance (ESR) dosimetry. The calibration of protection instruments are undertaken by the Ionising Radiation Standards Group within the Laboratory and by State Health Laboratories. (J.P.N.)

Evaluation of uncertainties in the calibration of radiation survey meter

International Nuclear Information System (INIS)

Potiens, M.P.A.; Santos, G.P.

2006-01-01

In order to meet the requirements of ISO 17025, the quantification of the expanded uncertainties of experimental data in the calibration of survey meters must be carried out using well defined concepts, like those expressed in the 'ISO-Guide to the Expression of Uncertainty in Measurement'. The calibration procedure of gamma ray survey meters involves two values that have to get their uncertainties clearly known: measurements of the instrument under calibration and the conventional true values of a quantity. Considering the continuous improvement of the calibration methods and set-ups, it is necessary to evaluate periodically the involved uncertainties in the procedures. In this work it is shown how the measurement uncertainties of an individual calibration can be estimated and how it can be generalized to be valid for others radiation survey meters. (authors)

Image-guided small animal radiation research platform: calibration of treatment beam alignment

International Nuclear Information System (INIS)

Matinfar, Mohammad; Iordachita, Iulian; Kazanzides, Peter; Ford, Eric; Wong, John

2009-01-01

Small animal research allows detailed study of biological processes, disease progression and response to therapy with the potential to provide a natural bridge to the clinical environment. The small animal radiation research platform (SARRP) is a portable system for precision irradiation with beam sizes down to approximately 0.5 mm and optimally planned radiation with on-board cone-beam CT (CBCT) guidance. This paper focuses on the geometric calibration of the system for high-precision irradiation. A novel technique for the calibration of the treatment beam is presented, which employs an x-ray camera whose precise positioning need not be known. Using the camera system we acquired a digitally reconstructed 3D 'star shot' for gantry calibration and then developed a technique to align each beam to a common isocenter with the robotic animal positioning stages. The calibration incorporates localization by cone-beam CT guidance. Uncorrected offsets of the beams with respect to the calibration origin ranged from 0.4 mm to 5.2 mm. With corrections, these alignment errors can be reduced to the sub-millimeter range. The calibration technique was used to deliver a stereotactic-like arc treatment to a phantom constructed with EBT Gafchromic films. All beams were shown to intersect at a common isocenter with a measured beam (FWHM) of approximately 1.07 mm using the 0.5 mm collimated beam. The desired positioning accuracy of the SARRP is 0.25 mm and the results indicate an accuracy of 0.2 mm. To fully realize the radiation localization capabilities of the SARRP, precise geometric calibration is required, as with any such system. The x-ray camera-based technique presented here provides a straightforward and semi-automatic method for system calibration.

Collimation system for a laboratory of primary and secondary ionizing radiation calibration

International Nuclear Information System (INIS)

Oliveira, S.R.; David, M.G.

2003-01-01

This work is part of a cooperation plan between the LNMRI/IRD and the LCR/UERJ, for the a primary calibration at the IRD and a secondary laboratory at the LCR, both calibrated for mammographic beams which will be part a Calibration National Network. For the mounting of the primary laboratory, the first step was to install two additional collimators in order to guarantee that the beam area over the ionization chamber to satisfy the calibration international standards. So, the collimators were constructed obeying the geometric rules, the first being of conic format and the second of the cylindrical format, therefore avoiding the effects of the scattering radiation on the edges. By using this collimation system it was possible to verify the uniformity of the radiation field incident the ionization chamber to be over 98% of the total area, guaranteeing better precision of the measurement

Implantation of radiodiagnostic reference radiations at the CDTN/CNEN for dosemeter calibration

International Nuclear Information System (INIS)

Baptista Neto, A.T.; Oliveira, P.M.C. de; Ferreira, F.C.B.

2009-01-01

A reliable dosimetry in diagnostic radiology is based on the traceability of calibrated and type-tested dosimeters in reference radiations that were established by the International Electrotechnical Commission (IEC). Metrology laboratories are expected to implement the reference radiations by reproducing the x-ray beam parameters within standard limits. This work shows the results of the implementation in the CDTN/CNEN-MG of the reference radiations for diagnostic radiology. The half value-layers and the homogeneity coefficients were determined for the primary (RQR), attenuated (RQA) and computerized tomography (RQT) x-ray beams. Results complied with the IEC limits which it means that the CDTN and the IEC reference radiations are similar and they can be used for calibration and type-testing of dosimeters to be used in diagnostic radiology. (author)

Synchrotron radiation calibration for soft X-ray detector

International Nuclear Information System (INIS)

Ning, Jiamin; Guo, Cun; Xu, Rongkun; Jiang, Shilun; Xu, Zeping; Chen, Jinchuan; Xia, Guangxin; Xue, Feibiao; Qin, Yi

2009-04-01

The calibration experiments were carried out to X-ray film, scintillator and transmission grating by employing the soft X-ray station at 3W1B beam-line in Beijing synchrotron Radiation Facility. The experiments presented the black intensity curve and energy response curve of soft X-ray film. And the experimental results can be used in diagnosis of X-ray radiation characterization of Z-pinch, such as in the measurement of soft X-ray Power Meter, grating spectrometer, pinhole camera and one-dimension imaging system which can ensure precision of Z-pinch results. (authors)

Conversion factors for the ICRU dose equivalent quantities for calibrating radiation dosemeters

International Nuclear Information System (INIS)

Grosswendt, B.; Hohlfeld, K.; Kramer, H.M.; Selbach, H.J.

1985-02-01

Report describing the application of conversion factors for monoenergetic photon radiation and for X and gamma reference radiation used for dosemeter calibration with the aid of spherical or rectangular phantoms (environmental and individual monitoring). (DG) [de

Reference radiation fields - Simulated workplace neutron fields - Part 2: Calibration fundamentals related to the basic quantities

International Nuclear Information System (INIS)

2008-01-01

ISO 8529-1, ISO 8529-2 and ISO 8529-3, deal with the production, characterization and use of neutron fields for the calibration of personal dosimeters and area survey meters. These International Standards describe reference radiations with neutron energy spectra that are well defined and well suited for use in the calibration laboratory. However, the neutron spectra commonly encountered in routine radiation protection situations are, in many cases, quite different from those produced by the sources specified in the International Standards. Since personal neutron dosimeters, and to a lesser extent survey meters, are generally quite energy dependent in their dose equivalent response, it might not be possible to achieve an appropriate calibration for a device that is used in a workplace where the neutron energy spectrum and angular distribution differ significantly from those of the reference radiation used for calibration. ISO 8529-1 describes four radionuclide based neutron reference radiations in detail. This part of ISO 12789 includes the specification of neutron reference radiations that were developed to closely resemble radiation that is encountered in practice

Calibration of GOES-derived solar radiation data using a distributed network of surface measurements in Florida, USA

Science.gov (United States)

Sumner, David M.; Pathak, Chandra S.; Mecikalski, John R.; Paech, Simon J.; Wu, Qinglong; Sangoyomi, Taiye; Babcock, Roger W.; Walton, Raymond

2008-01-01

Solar radiation data are critically important for the estimation of evapotranspiration. Analysis of visible-channel data derived from Geostationary Operational Environmental Satellites (GOES) using radiative transfer modeling has been used to produce spatially- and temporally-distributed datasets of solar radiation. An extensive network of (pyranometer) surface measurements of solar radiation in the State of Florida has allowed refined calibration of a GOES-derived daily integrated radiation data product. This refinement of radiation data allowed for corrections of satellite sensor drift, satellite generational change, and consideration of the highly-variable cloudy conditions that are typical of Florida. To aid in calibration of a GOES-derived radiation product, solar radiation data for the period 1995–2004 from 58 field stations that are located throughout the State were compiled. The GOES radiation product was calibrated by way of a three-step process: 1) comparison with ground-based pyranometer measurements on clear reference days, 2) correcting for a bias related to cloud cover, and 3) deriving month-by-month bias correction factors. Pre-calibration results indicated good model performance, with a station-averaged model error of 2.2 MJ m–2 day–1 (13 percent). Calibration reduced errors to 1.7 MJ m–2 day–1 (10 percent) and also removed time- and cloudiness-related biases. The final dataset has been used to produce Statewide evapotranspiration estimates.

X and gamma reference radiation for calibrating dosemeters and doserate meters and for determining their response as a function of photon energy - Part 4: Calibration of area and personal dosemeters in low energy X reference radiation fields

International Nuclear Information System (INIS)

2004-01-01

ISO 4037 consists of the following parts, under the general title X and gamma reference radiation for calibrating dosemeters and doserate meters and for determining their response as a function of photon energy: Part 1: Radiation characteristics and production methods; Part 2: Dosimetry for radiation protection over the energy ranges from 8 keV to 1,3 MeV and 4 MeV to 9 MeV; Part 3: Calibration of area and personal dosemeters and the measurement of their response as a function of energy and angle of incidence; Part 4: Calibration of area and personal dosemeters in low energy X reference radiation fields. This part 4. of ISO 4037 gives guidelines on additional aspects of the characterization of low energy photon radiations. This part of ISO 4037 also describes procedures for calibration and determination of the response of area and personal dose(rate)meters as a function of photon energy and angle of incidence. This part of ISO 4037 concentrates on the accurate determination of conversion coefficients from air kerma to Hp(10) and H*(10) for the spectra of low energy photon radiations. As an alternative to the use of conversion coefficients, the direct calibration in terms of these quantities by means of appropriate reference instruments is described

Building 772 - CERN’s new calibration facility for radiation protection instruments is ready to go

CERN Document Server

2014-01-01

Building 772 is becoming the new home of CERN’s calibration facility for radiation protection instrumentation. The new laboratory in Prévessin will be a state-of-the-art calibration facility and the first of its kind in both France and Switzerland, offering a wide range of possibilities with respect to radiation fields and instrumentation.   New four-axis calibration bench for radiation protection instruments.   Civil engineering work started in November 2013 in Prévessin and Building 772 is now finished and ready for inauguration. CERN’s calibration facility was previously located in Building 172 in Meyrin. Although still very accurate, the technology used was becoming obsolete and needed replacement. “Having considered different options, the decision was taken to build a new facility fully designed and conceived to meet all international safety and technical requirements of such a laboratory,” says Pie...

Characteristics of X ray calibration fields for performance test of radiation measuring instruments

International Nuclear Information System (INIS)

Shimizu, Shigeru; Takahashi, Fumiaki; Sawahata, Tadahiro; Tohnami, Kohichi; Kikuchi, Hiroshi; Murayama, Takashi

1999-02-01

Performance test and calibration of the radiation measuring instruments for low energy photons are made using the X ray calibration fields which are monochromatically characterized by filtration of continuous X ray spectrum. The X ray calibration field needs to be characterized by some quality conditions such as quality index and homogeneity coefficient. The present report describes quality conditions, spectrum and some characteristics of X ray irradiation fields in the Facility of Radiation Standard of the Japan Atomic Energy Research Institute (FRS-JAERI). Fifty nine X ray qualities with the quality index of 0.6, 0.7, 0.8 and 0.9 were set for the tube voltages between 10 kV and 350 kV. Estimation of X ray spectrum measured with a Ge detector was made in terms of exposure, ambient dose equivalent and fluence for all the obtained qualities. Practical irradiation field was determined as the dose distribution uniformity is within ±3%. The obtained results improve the quality of X ray calibration fields and calibration accuracy. (author)

Calibration of personnel monitors by exposure to gamma radiation with energies up to 9 MeV

International Nuclear Information System (INIS)

Leao, J.L.B.; Cunha, P.G. da; Diz, R.; Oberhofer, M.

Occupational exposure with photons of high energy (higher than those from 60 Co) might occur from nuclear reactors and accelerators. Radiation monitors for absorbed dose determination, however, often do not have a wall thickness sufficient to establish electronical equilibrium in that energy range. Using calibration factors determined for lower energies (calibration factors for 60 Co radiation) might cause a significant underestimation of the soft tissue absorbed dose. The calibration factor of the personnel monitors of the Eberline Instrument Co.based on TL dosimeters of LiF is reported. This monitor was calibrated with 9 MeV photons produced by thermal neutrons capture in a Nitarget, at an absorbed dose rate of 125 rads/h at the C.E.N. in France. The results are compared with the corresponding calibration factors for different energies up to 60 Co radiation determined in the IRD (Instituto de Radioprotecao e Dosimetria Rio de Janeiro). (Author) [pt

Survey and analysis of radiation safety management systems at medical institutions. Second report. Radiation measurement, calibration of radiation survey meters, and periodic check of installations, equipment, and protection instruments

International Nuclear Information System (INIS)

Ohba, Hisateru; Ogasawara, Katsuhiko; Aburano, Tamio

2006-01-01

We carried out a questionnaire survey to determine the actual situation of radiation safety management measures in all medical institutions in Japan that had nuclear medicine facilities. The questionnaire consisted of questions concerning the evaluation of shielding capacity; radiation measurement; periodic checks of installations, equipment, and protection instruments; and the calibration of radiation survey meters. The analysis was undertaken according to region, type of establishment, and number of beds. The overall response rate was 60 percent. For the evaluation of shielding capacity, the outsourcing rate was 53 percent of the total. For the radiation measurements of ''leakage radiation dose and radioactive contamination'' and contamination of radioactive substances in the air'', the outsourcing rates were 28 percent and 35 percent of the total, respectively (p<0.001, according to region and establishment). For the periodic check of radiation protection instruments, the implementation rate was 98 percent, and the outsourcing rate was 32 percent for radiation survey meters and 47 percent for lead aprons. The non-implemented rate for calibration of radiation survey meters was 25 percent of the total (p<0.001, according to region and establishment). The outsourcing rate for calibration of radiation survey meters accounted for 87 percent of the total, and of these medical institutions, 72 percent undertook annual calibration. The implementation rate for patient exposure measurement was 20 percent of the total (p<0.001, according to number of beds), and of these medical institutions 46 percent recorded measurement outcome. (author)

Development and implementation of an automated system for antiquated of the process of gamma radiation monitors calibration

International Nuclear Information System (INIS)

Silva Junior, Iremar Alves

2012-01-01

In this study it was carried out the development and implementation of a system for the appropriate process of gamma radiation monitors calibration, constituted by a pneumatic dispositive to exchange the attenuators and a positioning table, both actuated through a control panel. We also implemented a System of Caesa-Gammatron Irradiator, which increased the range of the air kerma rates, due to its higher activity comparing with the current system of gamma radiation in use in the calibration laboratory of gamma irradiation. Hence, it was necessary the installation of an attenuator dispositive remotely controlled in this irradiator system. Lastly, it was carried out an evaluation of the reduction in the rates of the occupational dose. This dissertation was developed with the aim of improving the quality of the services of calibration and tests of gamma radiation monitors - provided by the IPEN Laboratory of Instrument Calibration - as well as decreasing the occupational dose of the technicians involved in the process of calibration, following thus the principles of radiation protection. (author)

How to prepare a calibration laboratory for ionizing radiation using X rays

International Nuclear Information System (INIS)

Bossio, Francisco; Cardoso, Ricardo de Souza; Quaresma, Daniel da Silva; Batista Filha, Luzianete do Amaral; Peixoto, Jose Guilherme Pereira

2013-01-01

This work shows the main features of a system for calibration and testing of radiation detectors used in low and medium energy. It is based on pre-assembly System Laboratory of Metrology Division (DIMET) Institute of Radiation Protection and Dosimetry (IRD) of the National Commission of Nuclear Energy (CNEN). (author)

Nimbus-7 Earth radiation budget calibration history. Part 2: The Earth flux channels

Science.gov (United States)

Kyle, H. Lee; Hucek, Douglas Richard R.; Ardanuy, Philip E.; Hickey, John R.; Maschhoff, Robert H.; Penn, Lanning M.; Groveman, Brian S.; Vallette, Brenda J.

1994-01-01

Nine years (November 1978 to October 1987) of Nimbus-7 Earth radiation budget (ERB) products have shown that the global annual mean emitted longwave, absorbed shortwave, and net radiation were constant to within about + 0.5 W/sq m. Further, most of the small annual variations in the emitted longwave have been shown to be real. To obtain this measurement accuracy, the wide-field-of-view (WFOV) Earth-viewing channels 12 (0.2 to over 50 micrometers), 13 (0.2 to 3.8 micrometers), and 14 (0.7 to 2.8 micrometers) have been characterized in their satellite environment to account for signal variations not considered in the prelaunch calibration equations. Calibration adjustments have been derived for (1) extraterrestrial radiation incident on the detectors, (2) long-term degradation of the sensors, and (3) thermal perturbations within the ERB instrument. The first item is important in all the channels; the second, mainly in channels 13 and 14, and the third, only in channels 13 and 14. The Sun is used as a stable calibration source to monitor the long-term degradation of the various channels. Channel 12, which is reasonably stable to both thermal perturbations and sensor degradation, is used as a reference and calibration transfer agent for the drifting sensitivities of the filtered channels 13 and 14. Redundant calibration procedures were utilized. Laboratory studies complemented analyses of the satellite data. Two nearly independent models were derived to account for the thermal perturbations in channels 13 and 14. The global annual mean terrestrial shortwave and longwave signals proved stable enough to act as secondary calibration sources. Instantaneous measurements may still, at times, be in error by as much as a few Wm(exp -2), but the long-term averages are stable to within a fraction of a Wm(exp -2).

Re-Establishment of Standard Radiation Qualities for Calibration of Dosemeter in Diagnostic Radiology - RQR Series

International Nuclear Information System (INIS)

Asmaliza Hashim; Norhayati Abdullah; Mohd Firdaus Abd Rahman

2016-01-01

After repairing the high voltage (HV) generator for Philips MG165 X-Ray Machine, the reestablishment of the standard radiation qualities has been done at Medical Physics Calibration Laboratory to meet the IEC and IAEA standard. Standard radiation qualities are the important criteria for calibration of dosemeter in diagnostic radiology. Standard radiation qualities are defined as the added filtration needed to produce and the half value layer (HVL) of the beam for specifies x-ray tube kilo voltage (kV). For calibration of dosemeter in diagnostic radiology, standard radiation qualities RQR represent the beam incident on the patient in general radiography, fluoroscopy and dental application. The HVL were measured using PTW ion chamber of volume 1 cm"3 with PTW electrometer and aluminium filter with 99.9 % purity was used as additional filter for RQR and filter for HVL. The first establishment of standard radiation qualities was made in 2009 for the radiation qualities of RQR. The results of additional filter and 1st HVL from 2009 to 2016 will be discussed further in paper. The ratios of the measured HVL to the standard IEC HVL value for the RQR series also described in this paper. The details of the measurement and the results are described in this paper. (author)

Characterization of the radiation field of a 137Cs source in a calibration laboratory

International Nuclear Information System (INIS)

Barbosa, E.F.; Freitas, C.; Freire, D.; Almeida, C.E.

2001-01-01

Due to the broad range of radiation levels found in practice, the calibration of radiation detector requires that the laboratory have a large range of values of air kerma rates for a reference distance to the source, in order to allow the calibration of all scales. The dosimetry performed for open beam and with the different attenuators has shown deviations smaller than 5% in relation to the data supplied by the manufacturer that is acceptable. These results are in accordance with the recommendations of the ISO/DIS 4037-2

A research on radiation calibration of high dynamic range based on the dual channel CMOS

Science.gov (United States)

Ma, Kai; Shi, Zhan; Pan, Xiaodong; Wang, Yongsheng; Wang, Jianghua

2017-10-01

The dual channel complementary metal-oxide semiconductor (CMOS) can get high dynamic range (HDR) image through extending the gray level of the image by using image fusion with high gain channel image and low gain channel image in a same frame. In the process of image fusion with dual channel, it adopts the coefficients of radiation response of a pixel from dual channel in a same frame, and then calculates the gray level of the pixel in the HDR image. For the coefficients of radiation response play a crucial role in image fusion, it has to find an effective method to acquire these parameters. In this article, it makes a research on radiation calibration of high dynamic range based on the dual channel CMOS, and designs an experiment to calibrate the coefficients of radiation response for the sensor it used. In the end, it applies these response parameters in the dual channel CMOS which calibrates, and verifies the correctness and feasibility of the method mentioned in this paper.

Determination of the scattered radiation at the Neutron Calibration Laboratory of IPEN using the shadow cone method

Energy Technology Data Exchange (ETDEWEB)

Alvarenga, Tallyson S.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Freitas, Bruno M. [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Fonseca, Evaldo S.; Pereira, Walsan W., E-mail: talvarenga@ipen.br, E-mail: lcaldas@ipen.br, E-mail: bfreitas@con.ufrj.br, E-mail: walsan@ird.gov.br, E-mail: evaldo@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

Because of the increase in the demand for the calibration of neutron detectors, there is a need for new calibration services. In this context, the Calibration Laboratory of Instituto de Pesquisas Energéticas e Nucleares (IPEN), São Paulo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, has recently projected a new test laboratory for neutron detectors. This work evaluated the contribution of dispersed neutron radiation in this laboratory, using the cone shadow method and a Bonner sphere spectrometer to take the measurements at a distance of 100 cm from the neutron source. The dosimetric quantities H⁎(10) and H⁎(10) were obtained at the laboratory, allowing the calibration of detectors. (author)

Determination of the scattered radiation at the Neutron Calibration Laboratory of IPEN using the shadow cone method

International Nuclear Information System (INIS)

Alvarenga, Tallyson S.; Caldas, Linda V.E.; Freitas, Bruno M.

2017-01-01

Because of the increase in the demand for the calibration of neutron detectors, there is a need for new calibration services. In this context, the Calibration Laboratory of Instituto de Pesquisas Energéticas e Nucleares (IPEN), São Paulo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, has recently projected a new test laboratory for neutron detectors. This work evaluated the contribution of dispersed neutron radiation in this laboratory, using the cone shadow method and a Bonner sphere spectrometer to take the measurements at a distance of 100 cm from the neutron source. The dosimetric quantities H⁎(10) and H⁎(10) were obtained at the laboratory, allowing the calibration of detectors. (author)

Proceedings of the workshop on radiation survey instruments and calibrations

International Nuclear Information System (INIS)

Selby, J.M.; Swinth, K.L.; Vallario, E.J.; Murphy, B.L.

1985-11-01

The workshop was held to discuss two topics: first, a performance standard for radiation survey instruments and the potential for a testing program based on that standard; and second, a system of secondary standards laboratories to provide instrument calibrations and related services. Separate abstracts have been prepared for the individual presentations

First Calibrations of Alanine and Radio-Photo-Luminescence Dosemeters to a Hadronic Radiation Environment

CERN Document Server

Fürstner, Markus; Floret, Idelette; Forkel-Wirth, Doris; Mayer, Sabine; Menzel, Hans Gregor; Vincke, Helmut H

2005-01-01

Alanine and Radio-Photo-Luminescence (RPL) dosimeters are used to monitor radiation doses occurring inside the tunnels of all CERN accelerators including the Large Hadron Collider (LHC). They are placed close to radiation sensitive machine components like cables or insulation of magnet coils to predict their remaining lifetime. The dosimeters are exposed to mixed high-energy radiation fields. However, up to now both dosimeter types are calibrated to 60Co-photons only. In order to study the response of RPL and alanine dosimeters to mixed particle fields like those occurring at CERN's accelerators, an irradiation campaign at the CERN-EC High-Energy Reference field Facility (CERF-field) was performed. Moreover, the dosimeters were first time calibrated to a proton radiation field of a constant momentum of 24 GeV/c. In addition to the experiment FLUKA Monte Carlo simulations were carried out, which provide information concerning the energy deposition and the radiation field at the dosimeter locations.

Characterization of a Cs-137 radiation beam for dosimeter calibrations in the CRCN-CO

International Nuclear Information System (INIS)

Baptista Neto, Annibal T.; Soares, Carlos M. de A.; Silva, Teogenes A. da; Correa, Rosangela da S.

2009-01-01

The Centro Regional de Ciencias Nucleares do Centro Oeste (CRCN-CO) has played an important role in the environmental radiation monitoring program in Goiania city. The reduce its dependence of others monitoring laboratories, the CRCN-CO acquired a model 28 JL Shepherd and Associates irradiation system with a 137 Cs source for calibrations and frequent quality control checks of radiation dosimeters. A characterization of the irradiation system was carried out with the reference standard dosimeters that are maintained by the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN). The laboratory surrounding areas were monitored to demonstrate the adequate radiation protection conditions and parameters as the radiation field size, beam uniformity and the level of the scatter radiation were investigated. Dosimetry of the 137 Cs radiation beam in terms of air kerma rate was carried out at many source-detector distances with 4 (four) different beam lead attenuators. Results demonstrated that in spite of the radiation shutter automation is strongly recommended, the irradiation system is adequate and it complies with the requirements to be used for dosimeter irradiations and calibrations for the purpose of radiation protection. (author)

X radiation qualities characterization following the standard IEC 61267 recommendations at the calibration laboratory of IPEN

International Nuclear Information System (INIS)

Franciscatto, Priscila Cerutti

2009-01-01

This work presents a methodology for the X radiation qualities characterization following the new recommendations of the standard 61267 of the International Electrotechnical Commission (IEC) to establish a new procedure for calibration of dosimetric systems used in the field of diagnostic radiology. The reference qualities radiation of IEC 61267: RQR 2 to RQR 10, RQA 2 to RQA 10, RQB 2 to RQB 10 and RQN 2 to RQN 10 were implanted at the calibration laboratory of IPEN (LCI). Their characteristics were analyzed through measurements of beam parameters such as: Practical peak voltage (PPV), specific additional filtrations for each qualities (high purity aluminum of about 99.9%), 1st and 2nd Half Value Layers, homogeneity coefficient. The inherent filtration of the X ray tube was also determined. With the establishment of these radiation qualities, the LCI will be ready to calibrate the measuring instruments of radiation in the new qualities, allowing an improvement in radiological services offered by IPEN. (author)

Dosimeter calibration facilities and methods at the Radiation Measurement Laboratory of the Centre d'etudes nucleaires, Grenoble

International Nuclear Information System (INIS)

Choudens, H. de; Herbaut, Y.; Haddad, A.; Giroux, J.; Rouillon, J.; CEA Centre d'Etudes Nucleaires de Grenoble, 38

1975-01-01

At the Centre d'etudes nucleaires, Grenoble, the Radiation Measurement Laboratory, which forms part of the Environmental Protection and Research Department, serves the entire Centre for purposes of dosimetry and the calibration of dose meters. The needs of radiation protection are such that one must have facilities for checking periodically the calibration of radiation-monitoring instruments and developing special dosimetry techniques. It was thought a good idea to arrange for the dosimetry and radiation protection team to assist other groups working at the Centre - in particular, the staff of the biology and radiobiology laboratories - and also bodies outside the framework of the French Commissariat a l'energie atomique. Thus, technical collaboration has been established with, for example, Grenoble's Centre hospitalier universitaire (university clinic), which makes use of the facilities and skills available at the Radiation Measurement Laboratory for solving special dosimetry problems. With the Laboratory's facilities it is possible to calibrate dose meters for gamma, beta and neutron measurements

Upgrading the Medical Physics Calibration Laboratory Towards ISO/IEC 17025: Radiation Standards and Calibration in Diagnostic Radiology

International Nuclear Information System (INIS)

Asmaliza Hashim; Muhammad Jamal Md Isa; Abd Aziz Mhd Ramli; Wan Hazlinda Ismail; Norhayati Abdullah; Shahrul Azlan Azizan; Siti Sara Deraman; Nor Azlin Azraai; Md Khairusalih Md Zin

2010-01-01

Calibration of quality control (QC) test tools used in diagnostic radiology is legally required under the Ministry of Health (MOH) requirement. The Medical Physics Calibration Laboratory of the Malaysian Nuclear Agency is the national focal point for the calibration of quality control test tools used in diagnostic radiology. The Medical Physics Calibration Laboratory has measurement traceability to primary standard dosimetry laboratory (Physikalisch-Technische Bundesanstalt (PTB)), thus providing an interface between the primary standard dosimetry laboratory and Malaysian hospitals, clinics and license class H holder. The Medical Physics Calibration Laboratory facility is comprised of a constant potential x-ray system with a capability of 160 kV tube and a series of reference and working standard ion chambers. The stability of reference and working standard ion chambers was measured using strontium-90. Dosimetric instruments used in diagnostic radiology is calibrated in terms of air kerma to comply with an International Code of Practices of dosimetry for example IAEA's Technical Report Series number 457. The new series of standard radiation qualities was established based on ISO/IEC 61267. The measurement of beam homogeneity was measured using film and ion chamber to define the field size at certain distance and kV output was measured using the spectrometer and non-invasive kVp meter. The uncertainties measurement was determined with expended uncertainties to a level of confidence of approximately 95% (coverage factor k=2). This paper describes the available facility and the effort of the Medical Physics Calibration Laboratory to upgrade the laboratory towards ISO/IEC 17025. (author)

Calibration of diagnostic x-ray machines using radiation exposure and radiographic parameters

International Nuclear Information System (INIS)

Agba, E.H.; Uloko, P. I.; Tyovenda, A. A.

2011-01-01

Calibration of diagnostic x-ray machines using radiation exposure and radiographic parameters of the x-ray machines has been carried out. Three phase diagnostic x-ray machines situated at Federal Medical Centre, Makurdi, General Hospital, Otukpo and Christian Hospital, Mkar were used for the calibration work. The radiation meter was used to measure x-ray radiation exposure. The result of this work demonstrates mR/mAs=C(KV p ) that there exist a power law relation of the form between the radiation exposure and the radiographic parameters of diagnostic x-ray machines, which can be used to estimate patient exposure during routine x-ray diagnostic examinations for wide range of operating parameters. The values of the power exponent n, constant c and total filtrations of the diagnostic x-ray machines have been estimated. These values for the diagnostic x-ray machines at the Federal Medical Centre, Makurdi are: 2.14, 0.88 and 2.77 respectively, for the one at the General Hospital, Otukpo are: 2.07, 0.76 and 2.68 respectively and that of the Christian Hospital, Mkar are: 2.01,0.69 and 2.61 respectively.

New radiation protection calibration facility at CERN.

Science.gov (United States)

Brugger, Markus; Carbonez, Pierre; Pozzi, Fabio; Silari, Marco; Vincke, Helmut

2014-10-01

The CERN radiation protection group has designed a new state-of-the-art calibration laboratory to replace the present facility, which is >20 y old. The new laboratory, presently under construction, will be equipped with neutron and gamma sources, as well as an X-ray generator and a beta irradiator. The present work describes the project to design the facility, including the facility placement criteria, the 'point-zero' measurements and the shielding study performed via FLUKA Monte Carlo simulations. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Research on the calibration methods of the luminance parameter of radiation luminance meters

Science.gov (United States)

Cheng, Weihai; Huang, Biyong; Lin, Fangsheng; Li, Tiecheng; Yin, Dejin; Lai, Lei

2017-10-01

This paper introduces standard diffusion reflection white plate method and integrating sphere standard luminance source method to calibrate the luminance parameter. The paper compares the effects of calibration results by using these two methods through principle analysis and experimental verification. After using two methods to calibrate the same radiation luminance meter, the data obtained verifies the testing results of the two methods are both reliable. The results show that the display value using standard white plate method has fewer errors and better reproducibility. However, standard luminance source method is more convenient and suitable for on-site calibration. Moreover, standard luminance source method has wider range and can test the linear performance of the instruments.

Status of radiation dosimetry in Germany using ionization chamber calibrated in terms of absorbed dose to water

International Nuclear Information System (INIS)

Hohlfeld, Klaus; Roos, Martin

1995-01-01

In 1984 the PTB as PSDL and the DIN Standard Committee on Radiology (NAR) in close co-operation decided that in Germany the measured absorbed dose to water in a water phantom should replace exposure in the dosimetry for radiation therapy. The PTB has established primary standards of water absorbed dose in the whole range of photon and electron radiation, and international comparisons at the BIPM and with other PSDLs proved agreement within 0.5%. Secondary standards are calibrated in a water phantom under reference conditions in a Co-60 gamma radiation beam at the PTB. Thus, the calibration factor in terms of water absorbed dose, N W , is transferred to the manufacturers of dosimeters, the German Calibration Service and the dosimetry laboratories of the verification authorities. The Verification Law subjects each ionization dosimeter used in the treatment of patients with external photon radiation beams under a type-test at PTB and under a verification procedure, where the calibration factor, N W , must be shown to be within given limits. The absorbed dose determination at the users' level follows the foralism prescribed in the Standard DIN 6800-2 (1995) 'Procedures for Absorbed Dose Determination in Radiology by the Ionization Method'. The concept of this DIN Standard uses exclusively one quantity from the primary standard to the user's instrument eliminating uncertainties and sources of mistakes associated with the conversion of a calibration factor. The concept is simple and clear and covers the whole range of photon and electron radiation. As a means of quality assurance in basic dosimetry the PTB runs a calibration service, up to now on a voluntary basis, which allows the user to compare his dosimetry system against PTB standards using mailed Fricke ampoules, with water absorbed dose as measured and used

A comparison of absolute calibrations of a radiation thermometer based on a monochromator and a tunable source

Energy Technology Data Exchange (ETDEWEB)

Keawprasert, T. [National Institute of Metrology Thailand, Pathum thani (Thailand); Anhalt, K.; Taubert, D. R.; Sperling, A.; Schuster, M.; Nevas, S. [Physikalisch Technische Bundesanstalt, Braunschweig and Berlin (Germany)

2013-09-11

An LP3 radiation thermometer was absolutely calibrated at a newly developed monochromator-based set-up and the TUneable Lasers in Photometry (TULIP) facility of PTB in the wavelength range from 400 nm to 1100 nm. At both facilities, the spectral radiation of the respective sources irradiates an integrating sphere, thus generating uniform radiance across its precision aperture. The spectral irradiance of the integrating sphere is determined via an effective area of a precision aperture and a Si trap detector, traceable to the primary cryogenic radiometer of PTB. Due to the limited output power from the monochromator, the absolute calibration was performed with the measurement uncertainty of 0.17 % (k= 1), while the respective uncertainty at the TULIP facility is 0.14 %. Calibration results obtained by the two facilities were compared in terms of spectral radiance responsivity, effective wavelength and integral responsivity. It was found that the measurement results in integral responsivity at the both facilities are in agreement within the expanded uncertainty (k= 2). To verify the calibration accuracy, the absolutely calibrated radiation thermometer was used to measure the thermodynamic freezing temperatures of the PTB gold fixed-point blackbody.

A comparison of absolute calibrations of a radiation thermometer based on a monochromator and a tunable source

International Nuclear Information System (INIS)

Keawprasert, T.; Anhalt, K.; Taubert, D. R.; Sperling, A.; Schuster, M.; Nevas, S.

2013-01-01

An LP3 radiation thermometer was absolutely calibrated at a newly developed monochromator-based set-up and the TUneable Lasers in Photometry (TULIP) facility of PTB in the wavelength range from 400 nm to 1100 nm. At both facilities, the spectral radiation of the respective sources irradiates an integrating sphere, thus generating uniform radiance across its precision aperture. The spectral irradiance of the integrating sphere is determined via an effective area of a precision aperture and a Si trap detector, traceable to the primary cryogenic radiometer of PTB. Due to the limited output power from the monochromator, the absolute calibration was performed with the measurement uncertainty of 0.17 % (k= 1), while the respective uncertainty at the TULIP facility is 0.14 %. Calibration results obtained by the two facilities were compared in terms of spectral radiance responsivity, effective wavelength and integral responsivity. It was found that the measurement results in integral responsivity at the both facilities are in agreement within the expanded uncertainty (k= 2). To verify the calibration accuracy, the absolutely calibrated radiation thermometer was used to measure the thermodynamic freezing temperatures of the PTB gold fixed-point blackbody

Determination of the scattered radiation at the Neutron Calibration Laboratory of IPEN, SP, Brazil

International Nuclear Information System (INIS)

Alvarenga, Tallyson; Valeriano, Caio C.S.; Caldas, Linda V.E.; Federico, Claudio A.

2016-01-01

With the increased use of techniques using neutron radiation, there has been a considerable growth in the number of detectors for this kind of radiation. A neutron calibration laboratory with neutron radiation ("2"4"1AmBe) was designed. In practical situations of this type of laboratory, one of the main problems is related to the knowledge of scattered radiation. In order to evaluate this scattered radiation, simulations were carried out without the presence of structural elements and with the complete room. Fourteen measuring points were evaluated in different directions at various distances. (author)

Investigation on calibration parameter of mammography calibration facilities at MINT

International Nuclear Information System (INIS)

Asmaliza Hashim; Wan Hazlinda Ismail; Md Saion Salikin; Muhammad Jamal Md Isa; Azuhar Ripin; Norriza Mohd Isa

2004-01-01

A mammography calibration facility has been established in the Medical Physics Laboratory, Malaysian Institute for Nuclear Technology Research (MINT). The calibration facility is established at the national level mainly to provide calibration services for radiation measuring test instruments or test tools used in quality assurance programme in mammography, which is being implemented in Malaysia. One of the accepted parameters that determine the quality of a radiation beam is the homogeneity coefficient. It is determined from the values of the 1 st and 2 nd Half Value Layer (HVL). In this paper, the consistency of the mammography machine beam qualities that is available in MINT, is investigated and presented. For calibration purposes, five radiation qualities namely 23, 25, 28, 30 and 35 kV, selectable from the control panel of the X-ray machine is used. Important parameters that are set for this calibration facility are exposure time, tube current, focal spot to detector distance (FDD) and beam size at specific distance. The values of homogeneity coefficient of this laboratory for the past few years tip to now be presented in this paper. Backscatter radiations are also considered in this investigation. (Author)

Calibration and energy response of the Bitt RM10/RS02 gamma radiation detectors

International Nuclear Information System (INIS)

Dijk, E. van; Aalbers, A.H.L.

1990-03-01

A radiation monitoring network with automatic warning capabilities (LMR) has been established in the Netherlands. For the detection of gamma radiation exposure-rate-meters manufactured by Bitt Technologies are used. These meters consist of a proportional counter tube (type RS 02) and a read-out unit (type RM 10E). The photon energy response of 6 counter tubes was tested at the National Institute of Public Health and Environmental Protection. The measurements were performed with heavy filtered X-rays in the range of 50-250 keV (ISO narrow spectrum series) and with gamma ray beams from cesium-137 (662 keV) and cobalt-60 (1,25 MeV). To determine the energy response, the detector reading was referred to air kerma by means of a transfer ionization chamber. This transfer chamber was directly calibrated against the standard for X-rays. By applying these measurement procedures of a set of calibration factors (N k ) as a function of photon energy was determined. These calibration factors, expressed as the ratio air kerma to reading were converted to ambient dose equivalent calibration factors using appropriate conversion factors taken from Grosswend et al., 1988. From the measurement data an average ambient dose equivalent calibration factor of 10.8 mSv.roentgen -1 was calculated. (author). 5 refs.; 6 figs.; 5 tabs

Dealing with the size-of-source effect in the calibration of direct-reading radiation thermometer

Energy Technology Data Exchange (ETDEWEB)

Saunders, P. [Measurement Standards Laboratory of New Zealand, PO Box 31-310, Lower Hutt 5040 (New Zealand)

2013-09-11

The majority of general-purpose low-temperature handheld radiation thermometers are severely affected by the size-of-source effect (SSE). Calibration of these instruments is pointless unless the SSE is accounted for in the calibration process. Traditional SSE measurement techniques, however, are costly and time consuming, and because the instruments are direct-reading in temperature, traditional SSE results are not easily interpretable, particularly by the general user. This paper describes a simplified method for measuring the SSE, suitable for second-tier calibration laboratories and requiring no additional equipment, and proposes a means of reporting SSE results on a calibration certificate that should be easily understood by the non-specialist user.

Conception of the Instrument Calibration Laboratory of Ionizing Radiation Measurement (LACIMRI) of CTMSP - Sao Paulo, SP

International Nuclear Information System (INIS)

Silva, Raimundo Dias da; Kibrit, Eduardo

2009-01-01

The present work describes the phases of implantation of calibration laboratory of ionizing radiation measurement instruments at the CTMSP, Sao Paulo, in a priory approved by CNEN, Brazil. That laboratory will allow and enhance the present metrological capacity for the attendance to the growing demand for calibration services of the instruments

Nuclear energy - Reference beta-particle radiation - Part 2: Calibration fundamentals related to basic quantities characterizing the radiation field

International Nuclear Information System (INIS)

2004-01-01

ISO 6980 consists of the following parts, under the general title Nuclear energy - Reference beta-particle radiation: Part 1: Method of production; Part 2: Calibration fundamentals related to basic quantities characterizing the radiation field; Part 3: Calibration of area and personal dosimeters and determination of their response as a function of energy and angle of incidence. This part 2 of ISO 6980 specifies methods for the measurement of the directional absorbed-dose rate in a tissue-equivalent slab phantom in the ISO 6980 reference beta-particle radiation fields. The energy range of the beta-particle-emitting isotopes covered by these reference radiations is 0.066 to 3.54 MeV (maximum energy). Radiation energies outside this range are beyond the scope of this standard. While measurements in a reference geometry (depth of 0.07 mm at perpendicular incidence in a tissue-equivalent slab phantom) with a reference class extrapolation chamber are dealt with in detail, the use of other measurement systems and measurements in other geometries are also described, although in less detail. The ambient dose equivalent, H*(10) as used for area monitoring of strongly penetrating radiation, is not an appropriate quantity for any beta radiation, even for that penetrating a 10 mm thick layer of ICRU tissue (i.e. E max > 2 MeV). If adequate protection is provided at 0.07 mm, only rarely will one be concerned with other depths, for example 3 mm. This document is geared towards organizations wishing to establish reference-class dosimetry capabilities for beta particles, and serves as a guide to the performance of dosimetry with the reference class extrapolation chamber for beta-particle dosimetry in other fields. Guidance is also provided on the statement of measurement uncertainties

Establishment of a procedure to calculate the measurement uncertainties in radiation survey meters calibration

International Nuclear Information System (INIS)

Manzoli, J.E.; Potiens, M.P.A.

2000-01-01

The Calibration Laboratory of Sao Paulo calibrates more than one thousand gamma ray survey meters a year; beside other kinds of radiotherapy, radiodiagnostic and radiation protection instruments. It has a standard (600 cm 3 ) cylinder ionization chamber (Nuclear Enterprises Ltd. model 2511/3) traceable to the Brazilian Secondary Standard Dosimetry Laboratory (SSDL) whose instruments are traceable to the BIPM. Annually the beam dosimetry is performed using this chamber and the results are used as the true values for calibration purposes. The uncertainties present in every direct or indirect measurement during the calibration procedure must be evaluated for purposes of laboratory quality control. All calculation steps in the propagation of errors are presented in this work staging from the ionization chamber charge measured with the standard instrument. Such a propagation was made in space and time, considering even the environmental quantities uncertainties. The propagation was necessary in space, because the ionization chamber measurements were performed at only one space position. The time propagation was essential due to the fact that the activity is a peculiar physical quantity which changes with time according to precise relations for a specific radionuclide. The clear indication of every measurement uncertainty is always important to quantify the quality of this measurement. Nowadays the achievement of calibration laboratory quality systems requires the expression of all uncertainties and the procedure used to evaluate it. An example of this procedure in the case of the calibration of a typical portable radiation survey meter is presented. The direct exposure rate instrument measurement was compared with the true value given by the standard instrument properly propagated and all quantities used have their uncertainties shown. (author)

Calibration procedures of area monitors in terms of the Ambient Dose Equivalent H*(10), for gamma, x-ray radiation fields

International Nuclear Information System (INIS)

Dieguez Davila, L.E.

1998-01-01

In the present thesis procedures for calibrating portable survey meters in terms of the new ICRU quantities H*(10) ambient dose equivalent are discussed. Also the remendations of International Comission on Radiation Protection in their report ICRP 60 that inludes the operational magnitudes that the International Comission of Radiation Units proposed for calibrating area monitors

Field calibration of PADC track etch detectors for local neutron dosimetry in man using different radiation qualities

Energy Technology Data Exchange (ETDEWEB)

Haelg, Roger A., E-mail: rhaelg@phys.ethz.ch [Institute for Radiotherapy, Radiotherapie Hirslanden AG, Hirslanden Medical Center, Rain 34, CH-5000 Aarau (Switzerland); Besserer, Juergen [Institute for Radiotherapy, Radiotherapie Hirslanden AG, Hirslanden Medical Center, Rain 34, CH-5000 Aarau (Switzerland); Boschung, Markus; Mayer, Sabine [Division for Radiation Safety and Security, Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Clasie, Benjamin [Department of Radiation Oncology, Massachusetts General Hospital, 30 Fruit Street, Boston, MA 02114 (United States); Kry, Stephen F. [Department of Radiation Physics, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030 (United States); Schneider, Uwe [Institute for Radiotherapy, Radiotherapie Hirslanden AG, Hirslanden Medical Center, Rain 34, CH-5000 Aarau (Switzerland); Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 204, CH-8057 Zurich (Switzerland)

2012-12-01

In order to quantify the dose from neutrons to a patient for contemporary radiation treatment techniques, measurements inside phantoms, representing the patient, are necessary. Published reports on neutron dose measurements cover measurements performed free in air or on the surface of phantoms and the doses are expressed in terms of personal dose equivalent or ambient dose equivalent. This study focuses on measurements of local neutron doses inside a radiotherapy phantom and presents a field calibration procedure for PADC track etch detectors. An initial absolute calibration factor in terms of H{sub p}(10) for personal dosimetry is converted into neutron dose equivalent and additional calibration factors are derived to account for the spectral changes in the neutron fluence for different radiation therapy beam qualities and depths in the phantom. The neutron spectra used for the calculation of the calibration factors are determined in different depths by Monte Carlo simulations for the investigated radiation qualities. These spectra are used together with the energy dependent response function of the PADC detectors to account for the spectral changes in the neutron fluence. The resulting total calibration factors are 0.76 for a photon beam (in- and out-of-field), 1.00 (in-field) and 0.84 (out-of-field) for an active proton beam and 1.05 (in-field) and 0.91 (out-of-field) for a passive proton beam, respectively. The uncertainty for neutron dose measurements using this field calibration method is less than 40%. The extended calibration procedure presented in this work showed that it is possible to use PADC track etch detectors for measurements of local neutron dose equivalent inside anthropomorphic phantoms by accounting for spectral changes in the neutron fluence.

SU-E-J-47: Development of a High-Precision, Image-Guided Radiotherapy, Multi- Purpose Radiation Isocenter Quality-Assurance Calibration and Checking System

International Nuclear Information System (INIS)

Liu, C; Yan, G; Helmig, R; Lebron, S; Kahler, D

2014-01-01

Purpose: To develop a system that can define the radiation isocenter and correlate this information with couch coordinates, laser alignment, optical distance indicator (ODI) settings, optical tracking system (OTS) calibrations, and mechanical isocenter walkout. Methods: Our team developed a multi-adapter, multi-purpose quality assurance (QA) and calibration device that uses an electronic portal imaging device (EPID) and in-house image-processing software to define the radiation isocenter, thereby allowing linear accelerator (Linac) components to be verified and calibrated. Motivated by the concept that each Linac component related to patient setup for image-guided radiotherapy based on cone-beam CT should be calibrated with respect to the radiation isocenter, we designed multiple concentric adapters of various materials and shapes to meet the needs of MV and KV radiation isocenter definition, laser alignment, and OTS calibration. The phantom's ability to accurately define the radiation isocenter was validated on 4 Elekta Linacs using a commercial ball bearing (BB) phantom as a reference. Radiation isocenter walkout and the accuracy of couch coordinates, ODI, and OTS were then quantified with the device. Results: The device was able to define the radiation isocenter within 0.3 mm. Radiation isocenter walkout was within ±1 mm at 4 cardinal angles. By switching adapters, we identified that the accuracy of the couch position digital readout, ODI, OTS, and mechanical isocenter walkout was within sub-mm. Conclusion: This multi-adapter, multi-purpose isocenter phantom can be used to accurately define the radiation isocenter and represents a potential paradigm shift in Linac QA. Moreover, multiple concentric adapters allowed for sub-mm accuracy for the other relevant components. This intuitive and user-friendly design is currently patent pending

The calibration method for personal dosimetry system in photon and neutron radiation fields

Energy Technology Data Exchange (ETDEWEB)

Trousil, J; Plichta, J [CSOD, Prague (Czech Republic); Nikodemova, D [SOD, Bratislava (Slovakia)

1996-12-31

The type testing of dosimetry system was performed with standard photon radiation fields within the energy range 15 keV to 1.25 MeV and electron radiation fields within the range 0.2 MeV to 3 MeV. For type testing of neutron dosimeters {sup 252}Cf and {sup 241}Am-Be radionuclide neutron sources was used, as well as a 14 MeV neutron generator. The neutron sources moderated by various moderating and absorbing materials was also used. The routine calibration of individual photon dosemeters was carried out using a {sup 137}Cs calibration source in the air kerma quality in the dose range 0.2 mGy to 6 Gy. The type testing of neutron dosemeters was performed in collaboration with Nueherberg laboratory on neutron generator with neutron energies -.57; 1.0;; 5.3 and 15.1 MeV. The fading and angular dependence testing was also included in the tests of both dosemeter systems. (J.K.).

A theoretical approach to calibrate radiation portal monitor (RPM) systems

International Nuclear Information System (INIS)

Nafee, Sherif S.; Abbas, Mahmoud I.

2008-01-01

Radiation portal monitor (RPM) systems are widely used at international border crossings, where they are applied to the task of detecting nuclear devices, special nuclear material, and radiation dispersal device materials that could appear at borders. The requirements and constraints on RPM systems deployed at high-volume border crossings are significantly different from those at weapons facilities or steel recycling plants, the former being required to rapidly detect localized sources of radiation with a very high detection probability and low false-alarm rate, while screening all of the traffic without impeding the flow of commerce [Chambers, W.H., Atwater, H.F., Fehlau, P.E., Hastings, R.D., Henry, C.N., Kunz, W.E., Sampson, T.E., Whittlesey, T.H., Worth, G.M., 1974. Portal Monitor for Diversion Safeguards. LA-5681, Los Alamos Scientific Laboratory, Los Alamos, NM]. In the present work, compact analytical formulae are derived and used to calibrate two RPM systems with isotropic radiating sources: (i) polyvinyltoluene (PVT) or plastic and (ii) thallium-doped crystalline sodium iodide, NaI(Tl), gamma-ray detector materials. The calculated efficiencies are compared to measured values reported in the literatures, showing very good agreement

Status of ionization chambers calibration for radiation therapy in Brazil

Science.gov (United States)

Gonçalves, M.; Joana, G.; Leal, P.; Vasconcelos, R.; do Couto, N.; Teixeira, F. C.; Soares, A. D.; Santini, E. S.; Salata, C.

2018-03-01

CNEN makes a constant effort to keep updated with international standards and national needs to strengthen the radiological protection status of the country. The guidelines related to radiation treatment facilities have been revised in the last five years in order to take in consideration the most relevant aspects of the growing technology as well as to mitigate the accidents or incidents observed in practice. Hence, clinical dosimeters have gained special importance as significant items in Brazilian regulation. In the present work we discuss the importance of inspections from the point of view of equipment dosimetry and instruments quality control. The dosimeter sets based on thimble and well ionization chambers need periodic calibration, and this calibration becomes a fundamental task in order to guarantee the dose prescribed-delivered to patients. Thus Brazilian guidelines enforce the need of at least two sets of clinical dosimeters with thimble chambers calibrated and one set of electrometer with well ionization chamber for hdr equipment. We call attention to the fact that inspections are a very valuable tool in order to enforce the application of guidelines around the country both by enlightening the weaker aspects of facilities concerning radiological protection and by stating in loco that reasons which lead the regulatory body to enforce such guidelines items.

Automation of dosimeters calibration for radiotherapy in secondary dosimetric calibration laboratory of the CPHR

International Nuclear Information System (INIS)

Acosta, Andy L. Romero; Lores, Stefan Gutierrez

2013-01-01

This paper presents the design and implementation of an automated system for measurements in the calibration of reference radiation dosimeters. It was made a software application that performs the acquisition of the measured values of electric charge, calculated calibration coefficient and automates the calibration certificate issuance. These values are stored in a log file on a PC. The use of the application improves control over the calibration process, helps to humanize the work and reduces personnel exposure. The tool developed has been applied to the calibration of dosimeters radiation patterns in the LSCD of the Centro de Proteccion e Higiene de las Radiaciones, Cuba

Exercise for laboratory comparison of calibration coefficient in 137Cs beam, radiation protection - 2013/2014

International Nuclear Information System (INIS)

Cabral, T.S.; Potiens, M.P.A.; Soares, C.M.A.; Silveira, R.R.; Khoury, H.; Borges, J.C.

2015-01-01

This work deals with the preliminary results of the second exercise of comparing the radiation monitors calibration laboratories in Brazil. The exercise involved eight laboratories and the measured quantity is the air kerma in a beam of 137 Cs for radioprotection. The exercise was conducted by the LNMRI/IRD, in a star shaped arrangement from October 2013 to July 2015. The largest deviation was 2% of the calibration coefficient that is acceptable for applications in radioprotection. (author)

Laboratory for Calibration of Gamma Radiation Measurement Instruments (LabCal) of Institute of Chemical, Biological, Radiological and Nuclear Defense (IDQBRN) from Brazilian Army Technology Center (CTEx)

International Nuclear Information System (INIS)

Amorim, Aneuri de; Balthar, Mario Cesar V.; Santos, Avelino; Vilela, Paulo Ricardo T. de; Oliveira, Luciano Santa Rita; Penha, Paulo Eduardo C. de Oliveira; Gonzaga, Roberto Neves; Andrade, Edson Ramos de; Oliveira, Celio Jorge Vasques de; Fagundes, Luiz Cesar S.

2016-01-01

This paper describes the calibration laboratory deployment steps (LABCAL) gamma ionizing radiation measuring instruments in the Army Technology Center, CTEx. Initially the calibration of radiation monitors will be held in the dosimetric quantity air kerma and operational quantity ambient dose equivalent H*(d). The LABCAL / CTEx has not yet authorized by CASEC / CNEN. This laboratory aims to calibrate the ionizing radiation instruments used by the Brazilian Army. (author)

ORNL calibrations facility

International Nuclear Information System (INIS)

Berger, C.D.; Gupton, E.D.; Lane, B.H.; Miller, J.H.; Nichols, S.W.

1982-08-01

The ORNL Calibrations Facility is operated by the Instrumentation Group of the Industrial Safety and Applied Health Physics Division. Its primary purpose is to maintain radiation calibration standards for calibration of ORNL health physics instruments and personnel dosimeters. This report includes a discussion of the radioactive sources and ancillary equipment in use and a step-by-step procedure for calibration of those survey instruments and personnel dosimeters in routine use at ORNL

The radiation metrology network related to the field of mammography: implementation and uncertainty analysis of the calibration system

Science.gov (United States)

Peixoto, J. G. P.; de Almeida, C. E.

2001-09-01

It is recognized by the international guidelines that it is necessary to offer calibration services for mammography beams in order to improve the quality of clinical diagnosis. Major efforts have been made by several laboratories in order to establish an appropriate and traceable calibration infrastructure and to provide the basis for a quality control programme in mammography. The contribution of the radiation metrology network to the users of mammography is reviewed in this work. Also steps required for the implementation of a mammography calibration system using a constant potential x-ray and a clinical mammography x-ray machine are presented. The various qualities of mammography radiation discussed in this work are in accordance with the IEC 61674 and the AAPM recommendations. They are at present available at several primary standard dosimetry laboratories (PSDLs), namely the PTB, NIST and BEV and a few secondary standard dosimetry laboratories (SSDLs) such as at the University of Wisconsin and at the IAEA's SSDL. We discuss the uncertainties involved in all steps of the calibration chain in accord with the ISO recommendations.

Secondary calibration laboratory for ionizing radiation laboratory accreitation program National Institute of Standards and Technology National Voluntary Laboratory Accreditation Program

Energy Technology Data Exchange (ETDEWEB)

Martin, P.R.

1993-12-31

This paper presents an overview of the procedures and requirements for accreditation under the Secondary Calibration Laboratory for Ionizing Radiation Program (SCLIR LAP). The requirements for a quality system, proficiency testing and the onsite assessment are discussed. The purpose of the accreditation program is to establish a network of secondary calibration laboratories that can provide calibrations traceable to the primary national standards.

Secondary calibration laboratory for ionizing radiation laboratory accreitation program National Institute of Standards and Technology National Voluntary Laboratory Accreditation Program

International Nuclear Information System (INIS)

Martin, P.R.

1993-01-01

This paper presents an overview of the procedures and requirements for accreditation under the Secondary Calibration Laboratory for Ionizing Radiation Program (SCLIR LAP). The requirements for a quality system, proficiency testing and the onsite assessment are discussed. The purpose of the accreditation program is to establish a network of secondary calibration laboratories that can provide calibrations traceable to the primary national standards

Study of the alignment of X radiation beam for calibration of chambers used in radiotherapy

International Nuclear Information System (INIS)

Cardoso, Ricardo de Souza; Bossio, Francisco; Peixoto, Jose Guilherme Pereira

2014-01-01

The activities developed in radiotherapy, diagnostic radiology and radiation safety, require that the metrological parameters involving these activities have on its results a high degree of reliability, to ensure traceability. To meet the existing demand in Brazil, the National Metrology Laboratory of Ionizing Radiation - LNMRI - is deploying a new tube X-ray beams used in the calibration of the standard rooms, which serve to quality control in hospitals, clinics and industry. (author)

Calibration of thermoluminiscent materials

International Nuclear Information System (INIS)

Bos, A.J.J.

1989-07-01

In this report the relation between exposure and absorbed radiation dose in various materials is represented, on the base of recent data. With the help of this a calibration procedure for thermoluminescent materials, adapted to the IRI radiation standard is still the exposure in rontgen. In switching to the air kerma standard the calibration procedure will have to be adapted. (author). 6 refs.; 4 tabs

Reference beta radiations for calibrating dosemeters and dose ratemeters and for determining their response as a function of beta radiation energy. 1. ed.

International Nuclear Information System (INIS)

1984-01-01

This International Standard specifies the requirements for reference beta radiations produced by radionuclide sources to be used for the calibration of protection level dosemeters and dose ratemeters, and for the determination of their response as a function of beta energy. It gives the characteristics of radionuclides which have been used to produce reference beta radiations, gives examples of suitable source constructions and describes methods for the measurement of the residual maximum beta energy and the absorbed dose rate at a depth of 7 mg·cm -2 in a semi-infinite tissue-equivalent medium. The energy range involved lies between 66 keV and 3.6 MeV and the absorbed dose rates are in the range from about 10 μGy·h -1 (1 mrad·h -1 ) to at least 10 Gy·h -1 (10 3 rad·h -1 ). This International Standard proposes two series of beta reference radiations from which the radiation necessary for determining the characteristics (calibration and energy response) of an instrument shall be selected. Series 1 reference radiations are produced by radionuclide sources used with beam flattening filters designed to give uniform dose rates over a large area at a specific distance. The proposed sources of 90 Sr+ 90 Y, 204 TI and 147 Pm produce maximum dose rates of approximately 5mGy·h -1 (0.5 rad·h -1 ). Series 2 reference radiations are produced without the use of beam flattening filters which allows a range of source-to-calibration plane distances to be used. Close to the sources only relatively small areas of uniform dose rate are produced but this Series has the advantage of extending the energy and dose rate ranges beyond those of Series 1. The radionuclides used are those of Series 1 with the addition of the radionuclides 14 C and 106 Ru+ 106 Rh; these sources produce dose rates of up to 10 Gy·h -1 (10 3 rad·h -1 )

Calibrations and evaluation of the quality assurance during 1999 at the National Laboratory for ionising radiation

International Nuclear Information System (INIS)

Grindborg, Jan-Erik; Israelsson, Karl-Erik; Kylloenen, Jan-Erik; Samuelson, Goeran

2000-06-01

The Swedish Radiation Protection Institute is the National Laboratory for the dosimetric quantities kerma, absorbed dose and dose equivalent. The activity is based on established calibration procedures and a quality assurance program for the used standards. This report gives a brief summary of the calibrations performed during 1999 and a more detailed description and analysis of the quality assurance during this year. The report makes it easier to draw conclusions about the long-term stability and possible malfunctions

Estimation of photon energy distribution in gamma calibration field

International Nuclear Information System (INIS)

Takahashi, Fumiaki; Shimizu, Shigeru; Yamaguchi, Yasuhiro

1997-03-01

Photon survey instruments used for radiation protection are usually calibrated at gamma radiation fields, which are traceable to the national standard with regard to exposure. Whereas scattered radiations as well as primary gamma-rays exit in the calibration field, no consideration for the effect of the scattered radiations on energy distribution is given in routine calibration works. The scattered radiations can change photon energy spectra in the field, and this can result in misinterpretations of energy-dependent instrument responses. Construction materials in the field affect the energy distribution and magnitude of the scattered radiations. The geometric relationship between a gamma source and an instrument can determine the energy distribution at the calibration point. Therefore, it is essential for the assurance of quality calibration to estimate the energy spectra at the gamma calibration fields. Then, photon energy distributions at some fields in the Facility of Radiation Standard of the Japan Atomic Energy Research Institute (JAERI) were estimated by measurements using a NaI(Tl) detector and Monte Carlo calculations. It was found that the use of collimator gives a different feature in photon energy distribution. The origin of scattered radiations and the ratio of the scattered radiations to the primary gamma-rays were obtained. The results can help to improve the calibration of photon survey instruments in the JAERI. (author)

Performance of Different Light Sources for the Absolute Calibration of Radiation Thermometers

Science.gov (United States)

Martín, M. J.; Mantilla, J. M.; del Campo, D.; Hernanz, M. L.; Pons, A.; Campos, J.

2017-09-01

The evolving mise en pratique for the definition of the kelvin (MeP-K) [1, 2] will, in its forthcoming edition, encourage the realization and dissemination of the thermodynamic temperature either directly (primary thermometry) or indirectly (relative primary thermometry) via fixed points with assigned reference thermodynamic temperatures. In the last years, the Centro Español de Metrología (CEM), in collaboration with the Instituto de Óptica of Consejo Superior de Investigaciones Científicas (IO-CSIC), has developed several setups for absolute calibration of standard radiation thermometers using the radiance method to allow CEM the direct dissemination of the thermodynamic temperature and the assignment of the thermodynamic temperatures to several fixed points. Different calibration facilities based on a monochromator and/or a laser and an integrating sphere have been developed to calibrate CEM's standard radiation thermometers (KE-LP2 and KE-LP4) and filter radiometer (FIRA2). This system is based on the one described in [3] placed in IO-CSIC. Different light sources have been tried and tested for measuring absolute spectral radiance responsivity: a Xe-Hg 500 W lamp, a supercontinuum laser NKT SuperK-EXR20 and a diode laser emitting at 6473 nm with a typical maximum power of 120 mW. Their advantages and disadvantages have been studied such as sensitivity to interferences generated by the laser inside the filter, flux stability generated by the radiant sources and so forth. This paper describes the setups used, the uncertainty budgets and the results obtained for the absolute temperatures of Cu, Co-C, Pt-C and Re-C fixed points, measured with the three thermometers with central wavelengths around 650 nm.

NIST high-dose calibration services

International Nuclear Information System (INIS)

Humphreys, J.C.

1989-01-01

There is a need for the standardization of high-dose measurements used in the radiation-processing industry in order to provide assured traceability to national standards. NIST provides dosimetry calibration services to this industry. One of these services involves administration of known absorbed doses of gamma rays to customer-supplied dosimeters. The dosimeters are packaged to provide electron equilibrium conditions and are irradiated in a standard 60 Co calibration facility; this provides a calibration of that batch of dosimeters. Another service consists of supplying to a customer calibrated transfer dosimeters for irradiation with the customer's radiation source. The irradiated transfer dosimeters are then returned to NIST for analysis; the results are reported to the customer, providing a calibration of the dose rate of the customer's source. (orig.)

Very high-accuracy calibration of radiation pattern and gain of a near-field probe

DEFF Research Database (Denmark)

Pivnenko, Sergey; Nielsen, Jeppe Majlund; Breinbjerg, Olav

2014-01-01

In this paper, very high-accuracy calibration of the radiation pattern and gain of a near-field probe is described. An open-ended waveguide near-field probe has been used in a recent measurement of the C-band Synthetic Aperture Radar (SAR) Antenna Subsystem for the Sentinel 1 mission of the Europ...

Characterization and calibration of radiation-damaged double-sided silicon strip detectors

Energy Technology Data Exchange (ETDEWEB)

Kaya, L. [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Vogt, A., E-mail: andreas.vogt@ikp.uni-koeln.de [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Reiter, P.; Birkenbach, B.; Hirsch, R.; Arnswald, K.; Hess, H.; Seidlitz, M.; Steinbach, T.; Warr, N.; Wolf, K. [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Stahl, C.; Pietralla, N. [Institut für Kernphysik, Technische Universität Darmstadt, D-64291 Darmstadt (Germany); Limböck, T.; Meerholz, K. [Physikalische Chemie, Universität zu Köln, D-50939 Köln (Germany); Lutter, R. [Maier-Leibnitz-Laboratorium, Ludwig-Maximilians-Universität München, D-85748 Garching (Germany)

2017-05-21

Double-sided silicon strip detectors (DSSSD) are commonly used for event-by-event identification of charged particles as well as the reconstruction of particle trajectories in nuclear physics experiments with stable and radioactive beams. Intersecting areas of both p- and n-doped front- and back-side segments form individual virtual pixel segments allowing for a high detector granularity. DSSSDs are employed in demanding experimental environments and have to withstand high count rates of impinging nuclei. The illumination of the detector is often not homogeneous. Consequently, radiation damage of the detector is distributed non-uniformly. Position-dependent incomplete charge collection due to radiation damage limits the performance and lifetime of the detectors, the response of different channels may vary drastically. Position-resolved charge-collection losses between front- and back-side segments are investigated in an in-beam experiment and by performing radioactive source measurements. A novel position-resolved calibration method based on mutual consistency of p-side and n-side charges yields a significant enhancement of the energy resolution and the performance of radiation-damaged parts of the detector.

The ENEA calibration service for ionising radiations; Il centro di taratura per le radiazioni ionizzanti di Bologna. Parte 1: Fotoni

Energy Technology Data Exchange (ETDEWEB)

Monteventi, F.; Sermenghi, I. [ENEA, Centro Ricerche Ezio Clementel, Bologna (Italy). Dipt. Ambiente

1999-07-01

The report describes all the facilities available at the the service of the ENEA Calibration Service for Ionising Radiations at Bologna (Italy). It gives a detailed description of all equipment qualified for photon fields metrology including the secondary standards and the calibration procedures performed for radiation monitoring devices and dosemeters. [Italian] Il presente lavoro descrive i servizi e le attivita' del Centro di Taratura dell'ENEA di Bologna, in particolare delle attrezzature qualificate per la metrologia fotonica, dei campioni di misura e delle procedure adottate per la taratura degli strumenti e dei dosimetri.

A program on quality assurance and dose calibration for radiation therapy units in Venezuela

International Nuclear Information System (INIS)

Padilla, M.C. de; Carrizales, L.; Diaz, J.; Gutt, F.; Cozman, A.

1996-01-01

The results of a five year program (1988-90-91-92-93) on quality assurance and dose calibration for 12 Cobalt-60 units from public hospitals, which represents 30% of total radiation therapy units in Venezuela, are presented. The remarkable improvement in the general performance of these units can be seen in the IAEA/WHO Postal TLD Intercomparison results which gave 100% within ± 5% in 1990 and 1992, while 63% in 1990 and 44% in 1992, with errors up to 37% were obtained for the participants not included in the program. The difference between the two groups lead the government to decrete through the Gaceta Oficial de la Republica de Venezuela, Resolution G-1397 on March 3, 1993, the quality assurance and dose calibration programs shall be established for all radiation therapy installations in Venezuela. The project for the standards was developed by the SSDL physicists and it was already approbated by the Health Ministry. It is expected that the Norms will enter into effect by the end of 1994. (author). 14 refs, 1 fig., 3 tabs

A program on quality assurance and dose calibration for radiation therapy units in Venezuela

Energy Technology Data Exchange (ETDEWEB)

Padilla, M.C. de; Carrizales, L; Diaz, J; Gutt, F; Cozman, A [Instituto Venezolano de Investigaciones Cientificas, Caracas (Venezuela). Lab. de Calibracion Dosimetrica

1996-08-01

The results of a five year program (1988-90-91-92-93) on quality assurance and dose calibration for 12 Cobalt-60 units from public hospitals, which represents 30% of total radiation therapy units in Venezuela, are presented. The remarkable improvement in the general performance of these units can be seen in the IAEA/WHO Postal TLD Intercomparison results which gave 100% within {+-} 5% in 1990 and 1992, while 63% in 1990 and 44% in 1992, with errors up to 37% were obtained for the participants not included in the program. The difference between the two groups lead the government to decrete through the Gaceta Oficial de la Republica de Venezuela, Resolution G-1397 on March 3, 1993, the quality assurance and dose calibration programs shall be established for all radiation therapy installations in Venezuela. The project for the standards was developed by the SSDL physicists and it was already approbated by the Health Ministry. It is expected that the Norms will enter into effect by the end of 1994. (author). 14 refs, 1 fig., 3 tabs.

Experiences of a secondary laboratory of dosimetric calibration from the radiation protection and hygiene center CPHR in its first year of work and the procedures for quality assessment used in the calibration and quality control service

International Nuclear Information System (INIS)

Morales, J.A.; Campa, R.; Jova Sed, L.

1996-01-01

Experiences of a secondary laboratory of dosimetric calibration from the Radiation Protection and Hygiene Center (CPHR) in first year of work and the procedures for quality assessment used in the calibration and quality control service of radiotherapeutic equipment. For the yield calibration of the calibrated sources an ionometric method was used using ionizing chambers coupled to electrometers. Those determination were based on dosimetric American Association of Physicists in Medicine (AAPM)

Absolute calibration of sniffer probes on Wendelstein 7-X

International Nuclear Information System (INIS)

Moseev, D.; Laqua, H. P.; Marsen, S.; Stange, T.; Braune, H.; Erckmann, V.; Gellert, F.; Oosterbeek, J. W.

2016-01-01

Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up to 340 kW/m 2 per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m 2 per MW injected beam power is measured.

Absolute calibration of sniffer probes on Wendelstein 7-X

Science.gov (United States)

Moseev, D.; Laqua, H. P.; Marsen, S.; Stange, T.; Braune, H.; Erckmann, V.; Gellert, F.; Oosterbeek, J. W.

2016-08-01

Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up to 340 kW/m2 per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m2 per MW injected beam power is measured.

Absolute calibration of sniffer probes on Wendelstein 7-X

Energy Technology Data Exchange (ETDEWEB)

Moseev, D., E-mail: dmitry.moseev@ipp.mpg.de; Laqua, H. P.; Marsen, S.; Stange, T.; Braune, H.; Erckmann, V. [Max-Planck-Institut für Plasmaphysik, Greifswald (Germany); Gellert, F. [Max-Planck-Institut für Plasmaphysik, Greifswald (Germany); Ernst-Moritz-Arndt-Universität Greifswald, Greifswald (Germany); Oosterbeek, J. W. [Eindhoven University of Technology, Eindhoven (Netherlands)

2016-08-15

Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up to 340 kW/m{sup 2} per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m{sup 2} per MW injected beam power is measured.

Individual dosimetry and calibration

International Nuclear Information System (INIS)

Otto, T.

1997-01-01

In 1996, the Dosimetry and Calibration Section was, as in previous years, mainly engaged in routine tasks: the distribution of over 6000 dosimeters (with a total of more than 10,000 films) every two months and the calibration of about 900 fixed and mobile instruments used in the radiation survey sections of RP group. These tasks were, thanks to an experienced team, well mastered. Special efforts had to be made in a number of areas to modernize the service or to keep it in line with new prescriptions. The Individual Dosimetry Service had to assure that CERN's contracting firms comply with the prescriptions in the Radiation Safety Manual (1996) that had been inspired by the Swiss Ordinance of 1994: Companies must file for authorizations with the Swiss Federal Office for Public Health requiring that in every company an 'Expert in Radiation Protection' be nominated and subsequently trained. CERN's Individual Dosimetry Service is accredited by the Swiss Federal Authorities and works closely together with other, similar services on a rigorous quality assurance programme. Within this framework, CERN was mandated to organize this year the annual Swiss 'Intercomparison of Dosimeters'. All ten accredited dosimetry services - among others those of the Paul Scherrer Institute (PSI) in Villigen and of the four Swiss nuclear power stations - sent dosimeters to CERN, where they were irradiated in CERN's calibration facility with precise photon doses. After return to their origin they were processed and evaluated. The results were communicated to CERN and were compared with the originally given doses. A report on the results was subsequently prepared and submitted to the Swiss 'Group of Experts on Personal Dosimetry'. Reference monitors for photon and neutron radiation were brought to standard laboratories to assure the traceability of CERN's calibration service to the fundamental quantities. For photon radiation, a set of ionization chambers was calibrated in the reference field

Calibration of personal dosimeters: Quantities and terminology

International Nuclear Information System (INIS)

Aleinikov, V.E.

1999-01-01

The numerical results obtained in the interpretation of individual monitoring of external radiation depend not only on the accurate calibration of the radiation measurement instruments involved, but also on the definition of the quantities in term of which these instruments are calibrated The absence of uniformity in terminology not only makes it difficult to understand properly the scientific and technical literature but can also lead to incorrect interpretation of particular concepts and recommendations. In this paper, brief consideration is given to definition of radiation quantities and terminology used in calibration procedures. (author)

Calibration of dosemeters and survey instruments for photon

International Nuclear Information System (INIS)

Alamares, A.L.; Caseria, E.S.

1995-01-01

The Philippine Nuclear Research Institute (PNRI), the country's regulatory agency, through its Radiation Protection Unit of the Nuclear Regulations Licensing and Safeguard Division provides the calibration services of nuclear instruments used by various institutions. The periodic calibration and standardization of radiation and protection survey instruments are done to insure correct and valid radiation readings. It is also a regulatory requirement for radiation workers to use only operable and precalibrated survey instruments for their work with radioactive materials. The PNRI maintains and operates the Secondary Standard Dosimetry Laboratory (SSDL). It provides the periodic calibration and standardization of radiation monitoring and protection survey instruments, and also the radiological hazard and performance evaluation surveys of radiotherapy facilities and others. For the calibration of survey instruments, the standard sources of Cs-137 and Co-60 are used. The calibration procedures for survey meters and pocket dosimeters are explained. The clients served are shown. The personnel dosimetry using film badges, the application of ICRU operational quantities, and the problems encountered and recommendations are reported. (K.I.)

Evaluation of uncertainties in the calibration of radiation personal monitor with Cesium-137 source

International Nuclear Information System (INIS)

Mirapalheta, Tatiane; Alexandre, Anderson; Costa, Camila; Batista, Gilmar; Paulino, Thyago; Albuquerque, Marcos; Universidade do Estado do Rio de Janeiro

2016-01-01

This work shows the entire calibration process of an individual monitor, focusing on radiation protection, in health, correlating these measures associated uncertainties. The results show an expanded uncertainty of 5.81% for dose rate measurements and an expanded uncertainty of 5.61% for integrated dose measurements, these uncertainties have been evaluated the type A and type B with its components. (author)

Calibrating the radiation detector of the ventilation of a PET radiopharmaceutical production facility

International Nuclear Information System (INIS)

Lacerda, Marco Aurelio de Sousa; Tavares, Jose Carlos Freitas; Silva, Juliana Batista da

2011-01-01

The aim of this work is to demonstrate a new methodology of estimating the calibration factor of the ventilation duct of a PET radiopharmaceutical facility. The proposed methodology was studied to minimize contamination risks for the workers, as well as the uncertainties attributed to the gas sampling. The studied facility was the Development Centre of Nuclear Technology (CDTN/CNEN) in Belo Horizonte, Brazil. It was performed 3 consecutive irradiations with normal water (H 2 16 O) for production of nitrogen-13 to estimate the calibration factor of the detector located in the chimney of the facility. The readings of the detector were registered by the online radiation monitoring system (MEDISMARTS) during the transfer of the irradiated liquid until the count rate decreased for the background (BG) levels. The remaining activity of the water from the vial was measured and the decay corrected to the beginning of the transfer of the activity. The mean calibration factor estimated was (3.6 +- 0.5) kBq . m -3 . cps -1 . The maximum activities registered in the three irradiations were, respectively, 278 s, 370 s and 366 s after transferring of the activity to the hot cell. The conservative assumptions adopted and the values found for the calibration factor, which were close to the manufacturer published data, permit to estimate, safely, the discharges of radioactive gases in the installation. (author)

Absolute calibration of sniffer probes on Wendelstein 7-X

NARCIS (Netherlands)

Moseev, D.; Laqua, H.P.; Marsen, S.; Stange, T.; Braune, H.; Erckmann, V.; Gellert, F.J.; Oosterbeek, J.W.

Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of

Calibration of the radiation monitor onboard Akebono using Geant4

Science.gov (United States)

Asai, Keiko; Takashima, Takeshi; Koi, Tatsumi; Nagai, Tsugunobu

Natural high-energy electrons and protons (keV-MeV) in the space contaminate the data re-ciprocally. In order to calibrate the energy ranges and to remove data contamination on the radiation monitor (RDM) onboard the Japanese satellite, Akebono (EXOS-D), the detector is investigated using the Geant4 simulation toolkit of computational particle tracing. The semi-polar orbiting Akebono, launched in February 1989, is active now. This satellite has been observed the space environment at altitudes of several thousands km. The RDM instrument onboard Akebono monitors energetic particles in the Earth's radiation belt and gives important data accumulated for about two solar cycles. The data from RDM are for electrons in three energy channels of 0.3 MeV, protons in three energy channels of ¿ 30 MeV, and alpha particles in one energy channels of 15-45 MeV. The energy ranges are however based on information of about 20 years ago so that the data seem to include some errors actuary. In addition, these data include contamination of electrons and protons reciprocally. Actuary it is noticed that the electron data are contaminated by the solar protons but unknown quantitative amount of the contamination. Therefore we need data calibration in order to correct the energy ranges and to remove data contamination. The Geant4 simulation gives information of trajectories of incident and secondary particles whose are interacted with materials. We examine the RDM monitor using the Geant4 simulation. We find from the results that relativistic electrons of MeV behave quite complicatedly because of particle-material interaction in the instrument. The results indicate that efficiencies of detection and contamination are dependent on energy. This study compares the electron data from Akebono RDM with the simultaneous observation of CRRES and tries to lead the values of correction for each of the energy channels.

Calibration of solid state nuclear track detectors at high energy ion beams for cosmic radiation measurements: HAMLET results

International Nuclear Information System (INIS)

Szabó, J.; Pálfalvi, J.K.

2012-01-01

The MATROSHKA experiments and the related HAMLET project funded by the European Commission aimed to study the dose burden of the crew working on the International Space Station (ISS). During these experiments a human phantom equipped with several thousands of radiation detectors was exposed to cosmic rays inside and outside the ISS. Besides the measurements realized in Earth orbit, the HAMLET project included also a ground-based program of calibration and intercomparison of the different detectors applied by the participating groups using high-energy ion beams. The Space Dosimetry Group of the Centre for Energy Research (formerly Atomic Energy Research Institute) participated in these experiments with passive solid state nuclear track detectors (SSNTDs). The paper presents the results of the calibration experiments performed in the years 2008–2011 at the Heavy Ion Medical Accelerator (HIMAC) of the National Institute of Radiological Sciences (NIRS), Chiba, Japan. The data obtained serve as update and improvement for the previous calibration curves which are necessary for the evaluation of the SSNTDs exposed in unknown space radiation fields.

Calibration of solid state nuclear track detectors at high energy ion beams for cosmic radiation measurements: HAMLET results

Energy Technology Data Exchange (ETDEWEB)

Szabo, J., E-mail: julianna.szabo@energia.mta.hu [Hungarian Academy of Sciences, Centre for Energy Research, Konkoly Thege Miklos ut 29-33, 1525 Budapest 114, P.O. Box 49 (Hungary); Palfalvi, J.K. [Hungarian Academy of Sciences, Centre for Energy Research, Konkoly Thege Miklos ut 29-33, 1525 Budapest 114, P.O. Box 49 (Hungary)

2012-12-01

The MATROSHKA experiments and the related HAMLET project funded by the European Commission aimed to study the dose burden of the crew working on the International Space Station (ISS). During these experiments a human phantom equipped with several thousands of radiation detectors was exposed to cosmic rays inside and outside the ISS. Besides the measurements realized in Earth orbit, the HAMLET project included also a ground-based program of calibration and intercomparison of the different detectors applied by the participating groups using high-energy ion beams. The Space Dosimetry Group of the Centre for Energy Research (formerly Atomic Energy Research Institute) participated in these experiments with passive solid state nuclear track detectors (SSNTDs). The paper presents the results of the calibration experiments performed in the years 2008-2011 at the Heavy Ion Medical Accelerator (HIMAC) of the National Institute of Radiological Sciences (NIRS), Chiba, Japan. The data obtained serve as update and improvement for the previous calibration curves which are necessary for the evaluation of the SSNTDs exposed in unknown space radiation fields.

LET calibration for CR-39 detectors in different oxygen environments

International Nuclear Information System (INIS)

Zhou, D.; Semones, E.; Weyland, M.; Benton, E.R.

2007-01-01

High LET (linear energy transfer) radiation is the main contributor to the radiation field in low Earth orbit (LEO) in terms of dose equivalent. CR-39 plastic nuclear track detectors (PNTDs) can measure the LET spectrum and charge spectrum for the complicated radiation field in space. Previous research indicated that the sensitivity of CR-39 is different for CR-39 PNTDs working in different oxygen environments. LET calibration for CR-39 detectors in different oxygen environments is needed. Almost all the previous LET calibration work was carried out for CR-39 detectors in good-oxygen condition, LET calibration work for CR-39 in poor-oxygen condition has not been conducted until our work. Systematic LET calibrations were carried out by JSC-SRAG (Space Radiation Analysis Group) for CR-39 detectors working in different oxygen environments and abundant results of LET calibrations were obtained. This paper introduces the method for CR-39 LET calibration, presents and discusses the calibration results and some applications

Guidelines on calibration of neutron measuring devices

International Nuclear Information System (INIS)

Burger, G.

1988-01-01

The International Atomic Energy Agency and the World Health Organization have agreed to establish an IAEA/WHO Network of Secondary Standard Dosimetry Laboratories (SSDLs) in order to improve accuracy in applied radiation dosimetry throughout the world. These SSDLs must be equipped with, and maintain, secondary standard instruments, which have been calibrated against primary standards, and must be nominated by their governments for membership of the network. The majority of the existing SSDLs were established primarily to work with photon radiation (X-rays and gamma rays). Neutron sources are, however, increasingly being applied in industrial processes, research, nuclear power development and radiation biology and medicine. Thus, it is desirable that the SSDLs in countries using neutron sources on a regular basis should also fulfil the minimum requirements to calibrate neutron measuring devices. It is the primary purpose of this handbook to provide guidance on calibration of instruments for radiation protection. A calibration laboratory should also be in a position to calibrate instrumentation being used for the measurement of kerma and absorbed dose and their corresponding rates. This calibration is generally done with photons. In addition, since each neutron field is usually contaminated by photons produced in the source or by scatter in the surrounding media, neutron protection instrumentation has to be tested with respect to its intrinsic photon response. The laboratory will therefore need to possess equipment for photon calibration. This publication deals primarily with methods of applying radioactive neutron sources for calibration of instrumentation, and gives an indication of the space, manpower and facilities needed to fulfil the minimum requirements of a calibration laboratory for neutron work. It is intended to serve as a guide for centres about to start on neutron dosimetry standardization and calibration. 94 refs, 8 figs, 12 tabs

Calibrations of pocket dosemeters using a comparison method

International Nuclear Information System (INIS)

Somarriba V, I.

1996-01-01

This monograph is dedicated mainly to the calibration of pocket dosemeters. Various types of radiation sources used in hospitals and different radiation detectors with emphasis on ionization chambers are briefly presented. Calibration methods based on the use of a reference dosemeter were developed to calibrate all pocket dosemeters existing at the Radiation Physics and Metrology Laboratory. Some of these dosemeters were used in personnel dosimetry at hospitals. Moreover, a study was realized about factors that affect the measurements with pocket dosemeters in the long term, such as discharges due to cosmic radiation. A DBASE IV program was developed to store the information included in the hospital's registry

Project, construction and calibration of parallel plate ionization chambers for x-radiation

International Nuclear Information System (INIS)

Albuquerque, M.P.P.

1989-01-01

Two pairs of parallel-plate ionization chambers were projected and constructed. In each pair one of the chambers has a collecting electrode and a guard ring made of graphite and the other, of aluminium. The difference between both pairs is that in only one case screws were used to fix the chamber components. The chambers are made of Lucite with aluminized Mylar entrance windows; they have circular form and are unsealed. All chamber components are easily available. The main chamber characteristics were determined, applying the tests of current leakage, repetitively and long term stability. The energy and angular dependence, and the polarity effect were also studied, obtaining the saturation curves and determining the build-up effect for gamma radiation detection. The chambers were calibrated with low and intermediate energy X-radiation, gamma radiation of sup(60)Co an sup(137)Cs, and beta radiation of sup(90)Sr + sup(90)Y. The obtained results show the viability of utilization of these chambers in radiation dosimetry and the results were compared with those of imported commercial ionization chambers of the secondary standard type. The great difference between the energy dependence of the chambers according to the collecting electrode material, allowed the formation of a Tandem system (constituted by a chamber pair A, C), for the determination of the effective energy and the exposure rate in air of unknown X-radiation fields, in the case of low intermediate energy ranges. (author)

Calibration and evaluation of the FAO56-Penman-Monteith, FAO24-radiation, and Priestly-Taylor reference evapotranspiration models using the spatially measured solar radiation across a large arid and semi-arid area in southern Iran

Science.gov (United States)

Didari, Shohreh; Ahmadi, Seyed Hamid

2018-05-01

Crop evapotranspiration (ET) is one of the main components in calculating the water balance in agricultural, hydrological, environmental, and climatological studies. Solar radiation (Rs) supplies the available energy for ET, and therefore, precise measurement of Rs is required for accurate ET estimation. However, measured Rs and ET and are not available in many areas and they should be estimated indirectly by the empirical methods. The Angström-Prescott (AP) is the most popular method for estimating Rs in areas where there are no measured data. In addition, the locally calibrated coefficients of AP are not yet available in many locations, and instead, the default coefficients are used. In this study, we investigated different approaches for Rs and ET calculations. The daily measured Rs values in 14 stations across arid and semi-arid areas of Fars province in south of Iran were used for calibrating the coefficients of the AP model. Results revealed that the calibrated AP coefficients were very different and higher than the default values. In addition, the reference ET (ET o ) was estimated by the FAO56 Penman-Monteith (FAO56 PM) and FAO24-radiation methods by using the measured Rs and were then compared with the measured pan evaporation as an indication of the potential atmospheric demand. Interestingly and unlike many previous studies, which have suggested the FAO56 PM as the standard method in calculation of ET o , the FAO24-radiation with the measured Rs showed better agreement with the mean pan evaporation. Therefore, the FAO24-radiation with the measured Rs was used as the reference method for the study area, which was also confirmed by the previous studies based on the lysimeter data. Moreover, the accuracy of calibrated Rs in the estimation of ET o by the FAO56 PM and FAO24-radiation was investigated. Results showed that the calibrated Rs improved the accuracy of the estimated ET o by the FAO24-radiation compared with the FAO24-radiation using the measured

Sistema electrónico de calibración de fruta por diámetro

OpenAIRE

Cruz Lemus, Erico

2013-01-01

En la actualidad, las cooperativas recolectan, seleccionan, tratan y separan la fruta según su calibre (peso, diámetro máximo, medio y/o mínimo) para que esta llegue al consumidor final según la categoría (calibre). Para poder competir en un mercado cada vez más exigente en calidad y precios, se requieren sistemas de clasificación automáticos que nos permitan obtener óptimos resultados con altos niveles de producción y productividad. Para realizar estas tareas existen calibr...

Radiometric calibration of the in-flight blackbody calibration system of the GLORIA interferometer

Directory of Open Access Journals (Sweden)

C. Monte

2014-01-01

Atmosphere is an airborne, imaging, infrared Fourier transform spectrometer that applies the limb-imaging technique to perform trace gas and temperature measurements in the Earth's atmosphere with three-dimensional resolution. To ensure the traceability of these measurements to the International Temperature Scale and thereby to an absolute radiance scale, GLORIA carries an on-board calibration system. Basically, it consists of two identical large-area and high-emissivity infrared radiators, which can be continuously and independently operated at two adjustable temperatures in a range from −50 °C to 0 °C during flight. Here we describe the radiometric and thermometric characterization and calibration of the in-flight calibration system at the Reduced Background Calibration Facility of the Physikalisch-Technische Bundesanstalt. This was performed with a standard uncertainty of less than 110 mK. Extensive investigations of the system concerning its absolute radiation temperature and spectral radiance, its temperature homogeneity and its short- and long-term stability are discussed. The traceability chain of these measurements is presented.

Quality control of calibration system for area monitors at National Laboratory of Metrology from Ionizing Radiations (LNMRI)

International Nuclear Information System (INIS)

Ramos, M.M.O.; Freitas, L.C. de

1992-01-01

The quality control of equipment used in calibration from the National Laboratory of Metrology on Ionizing Radiations is presented, with results of standard measure systems and irradiation system. Tables and graphics with the quality of systems are also shown. (C.G.C.)

Automation of the Calibration of Reference Dosimeters Used in Radiotherapy

International Nuclear Information System (INIS)

Romero Acosta, A.; Gutierrez Lores, S.

2013-01-01

Traceability, accuracy and consistency of radiation measurements are essential in radiation dosimetry, particularly in radiotherapy, where the outcome of treatments is highly dependent on the radiation dose delivered to patients. The role of Secondary Standard Dosimetry Laboratories (SSDLs) is crucial in providing traceable calibrations to hospitals, since these laboratories disseminate calibrations at specific radiation qualities appropriate to the use of radiation measuring instruments. These laboratories follow IAEA/WHO guidelines for calibration procedures, often being current and charge measurements described in these guidelines a tedious task. However, these measurements are usually done using modern electrometers which are equipped with a RS-232 interface that allows instrument control from a PC. This paper presents the design and employment of an automated system aimed to the measurements of the radiotherapy dosimeters calibration process for Cobalt-60 gamma rays. A software was developed using Lab View, in order to achieve the acquisition of the charge values measured, calculation of the calibration coefficient and issue of a calibration certificate. A primary data report file is filled and stored in the PC's hard disk. By using this software tool, a better control over the calibration process is achieved, it reduces the need for human intervention and it also reduces the exposure of the laboratory staff. The automated system has been used for the calibration of reference dosimeters used in radiotherapy at the Cuban Secondary Standard Dosimetry Laboratory of the Center for Radiation Protection and Hygiene (Author)

Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research

Energy Technology Data Exchange (ETDEWEB)

Yang, Yidong, E-mail: yidongyang@med.miami.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 and Department of Radiation Oncology, University of Miami School of Medicine, Miami, Florida 33136 (United States); Wang, Ken Kang-Hsin; Wong, John W. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 (United States); Eslami, Sohrab; Iordachita, Iulian I. [Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Patterson, Michael S. [Juravinski Cancer Centre and Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S4K1 (Canada)

2015-04-15

Purpose: The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides excellent bone to soft tissue contrast, but is incapable of differentiating tumors from surrounding soft tissue. Bioluminescence tomography (BLT), in contrast, allows direct visualization of even subpalpable tumors and quantitative evaluation of tumor response. Integration of BLT with CBCT offers complementary image information, with CBCT delineating anatomic structures and BLT differentiating luminescent tumors. This study is to develop a systematic method to calibrate an integrated CBCT and BLT imaging system which can be adopted onboard the SARRP to guide focal tumor irradiation. Methods: The integrated imaging system consists of CBCT, diffuse optical tomography (DOT), and BLT. The anatomy acquired from CBCT and optical properties acquired from DOT serve as a priori information for the subsequent BLT reconstruction. Phantoms were designed and procedures were developed to calibrate the CBCT, DOT/BLT, and the entire integrated system. Geometrical calibration was performed to calibrate the CBCT system. Flat field correction was performed to correct the nonuniform response of the optical imaging system. Absolute emittance calibration was performed to convert the camera readout to the emittance at the phantom or animal surface, which enabled the direct reconstruction of the bioluminescence source strength. Phantom and mouse imaging were performed to validate the calibration. Results: All calibration procedures were successfully performed. Both CBCT of a thin wire and a euthanized mouse revealed no spatial artifact, validating the accuracy of the CBCT calibration. The absolute emittance calibration was validated with a 650 nm laser source, resulting in a 3

Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research

International Nuclear Information System (INIS)

Yang, Yidong; Wang, Ken Kang-Hsin; Wong, John W.; Eslami, Sohrab; Iordachita, Iulian I.; Patterson, Michael S.

2015-01-01

Purpose: The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides excellent bone to soft tissue contrast, but is incapable of differentiating tumors from surrounding soft tissue. Bioluminescence tomography (BLT), in contrast, allows direct visualization of even subpalpable tumors and quantitative evaluation of tumor response. Integration of BLT with CBCT offers complementary image information, with CBCT delineating anatomic structures and BLT differentiating luminescent tumors. This study is to develop a systematic method to calibrate an integrated CBCT and BLT imaging system which can be adopted onboard the SARRP to guide focal tumor irradiation. Methods: The integrated imaging system consists of CBCT, diffuse optical tomography (DOT), and BLT. The anatomy acquired from CBCT and optical properties acquired from DOT serve as a priori information for the subsequent BLT reconstruction. Phantoms were designed and procedures were developed to calibrate the CBCT, DOT/BLT, and the entire integrated system. Geometrical calibration was performed to calibrate the CBCT system. Flat field correction was performed to correct the nonuniform response of the optical imaging system. Absolute emittance calibration was performed to convert the camera readout to the emittance at the phantom or animal surface, which enabled the direct reconstruction of the bioluminescence source strength. Phantom and mouse imaging were performed to validate the calibration. Results: All calibration procedures were successfully performed. Both CBCT of a thin wire and a euthanized mouse revealed no spatial artifact, validating the accuracy of the CBCT calibration. The absolute emittance calibration was validated with a 650 nm laser source, resulting in a 3

Calibration of proportional counters in microdosimetry

International Nuclear Information System (INIS)

Varma, M.N.

1982-01-01

Many microdosimetric spectra for low LET as well as high LET radiations are measured using commercially available (similar to EG and G) Rossi proportional counters. This paper discusses the corrections to be applied to data when calibration of the counter is made using one type of radiation, and then the counter is used in a different radiation field. The principal correction factor is due to differences in W-value of the radiation used for calibration and the radiation for which microdosimetric measurements are made. Both propane and methane base tissue-equivalent (TE) gases are used in these counters. When calibrating the detectors, it is important to use the correct stopping power value for that gas. Deviations in y-bar/sub F/ and y-bar/sub D/ are calculated for 60 Co using different extrapolation procedures from 0.15 keV/μm to zero event size. These deviations can be as large as 30%. Advantages of reporting microdosimetric parameters such as y-bar/sub F/ and y-bar/sub D/ above a certain minimum cut-off are discussed

HPS instrument calibration laboratory accreditation program

Energy Technology Data Exchange (ETDEWEB)

Masse, F.X; Eisenhower, E.H.; Swinth, K.L.

1993-12-31

The purpose of this paper is to provide an accurate overview of the development and structure of the program established by the Health Physics Society (HPS) for accrediting instrument calibration laboratories relative to their ability to accurately calibrate portable health physics instrumentation. The purpose of the program is to provide radiation protection professionals more meaningful direct and indirect access to the National Institute of Standards and Technology (NIST) national standards, thus introducing a means for improving the uniformity, accuracy, and quality of ionizing radiation field measurements. The process is designed to recognize and document the continuing capability of each accredited laboratory to accurately perform instrument calibration. There is no intent to monitor the laboratory to the extent that each calibration can be guaranteed by the program; this responsibility rests solely with the accredited laboratory.

Biological dosimetry of ionizing radiation: Evaluation of the dose with cytogenetic methodologies by the construction of calibration curves

Science.gov (United States)

Zafiropoulos, Demetre; Facco, E.; Sarchiapone, Lucia

2016-09-01

In case of a radiation accident, it is well known that in the absence of physical dosimetry biological dosimetry based on cytogenetic methods is a unique tool to estimate individual absorbed dose. Moreover, even when physical dosimetry indicates an overexposure, scoring chromosome aberrations (dicentrics and rings) in human peripheral blood lymphocytes (PBLs) at metaphase is presently the most widely used method to confirm dose assessment. The analysis of dicentrics and rings in PBLs after Giemsa staining of metaphase cells is considered the most valid assay for radiation injury. This work shows that applying the fluorescence in situ hybridization (FISH) technique, using telomeric/centromeric peptide nucleic acid (PNA) probes in metaphase chromosomes for radiation dosimetry, could become a fast scoring, reliable and precise method for biological dosimetry after accidental radiation exposures. In both in vitro methods described above, lymphocyte stimulation is needed, and this limits the application in radiation emergency medicine where speed is considered to be a high priority. Using premature chromosome condensation (PCC), irradiated human PBLs (non-stimulated) were fused with mitotic CHO cells, and the yield of excess PCC fragments in Giemsa stained cells was scored. To score dicentrics and rings under PCC conditions, the necessary centromere and telomere detection of the chromosomes was obtained using FISH and specific PNA probes. Of course, a prerequisite for dose assessment in all cases is a dose-effect calibration curve. This work illustrates the various methods used; dose response calibration curves, with 95% confidence limits used to estimate dose uncertainties, have been constructed for conventional metaphase analysis and FISH. We also compare the dose-response curve constructed after scoring of dicentrics and rings using PCC combined with FISH and PNA probes. Also reported are dose response curves showing scored dicentrics and rings per cell, combining

Calibration of ionization chamber survey meter

International Nuclear Information System (INIS)

Kadhim, A.K.; Kadni, T.B.

2016-01-01

Radiation measuring devices need to process calibration which lose their sensitivity and the extent of the response and the amount of stability under a changing conditions from time to time and this period depends on the nature and use of field in which used devices. A comparison study was done toa (45 I P) ( ionization chamber survey meter) and this showed the variation factor in five different years. This study also displayed the concept of radiation instrument calibration and necessity of every year calibration of them.In this project we used the five years calibration data for ionization chamber survey meter model Inspector (1/C F). the value deviation (∆ %) of Cfs for four years of calibration in comparison of C F for the year 2007 are very high and the device under research is not good to use in field and reliable because the ionization chamber is very sensitive to humidity and must calibrate a year or less, or due ing every two years and must maintain carefully to reduce the discarded effects the measurements.

Calibration of photographic dosemeters to evaluate the personal equivalent dose, Hp (10), irradiated by different radiation qualities and angles of incidence

International Nuclear Information System (INIS)

Santoro, Christiana; Antonio Filho, Joao

2013-01-01

To use radiation detectors, should periodically perform tests and calibrations on instruments in order to verify its good functionality. One way to ascertain the quality of the instrument is to conduct a study of the angular dependence of the response of the radiation detectors. The photographic dosimetry has been used widely to quantify the radiation doses and to estimate levels of doses received by workers involved with X-and gamma radiation. Photographic dosimeters are used because provide wide range of exposure and good accuracy. One of the sources of error have been introduced by different irradiation geometries between calibration and measurement in radiation fields used in x-ray and gamma ray sources, therefore, there is a need for an evaluation of the sensitivity of dosimeters with variation of the angle of the incident beam. In this study were tested 190 photographic dosemeters in the Metrology Laboratory of the Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE) using the phantom H p (10), where the dosimeters are evaluated on the basis of the new operational magnitude for individual monitoring, the equivalent personal dose, H p (10). Angular dependence of these radiation detectors was studied in X radiation fields (in the range of 45 keV energy to 164 keV) and gamma radiation ( 137 Cs-662 keV e 60 Co - 1250 keV)

Radiometric Cross-Calibration of GAOFEN-1 Wfv Cameras with LANDSAT-8 Oli and Modis Sensors Based on Radiation and Geometry Matching

Science.gov (United States)

Li, J.; Wu, Z.; Wei, X.; Zhang, Y.; Feng, F.; Guo, F.

2018-04-01

Cross-calibration has the advantages of high precision, low resource requirements and simple implementation. It has been widely used in recent years. The four wide-field-of-view (WFV) cameras on-board Gaofen-1 satellite provide high spatial resolution and wide combined coverage (4 × 200 km) without onboard calibration. In this paper, the four-band radiometric cross-calibration coefficients of WFV1 camera were obtained based on radiation and geometry matching taking Landsat 8 OLI (Operational Land Imager) sensor as reference. Scale Invariant Feature Transform (SIFT) feature detection method and distance and included angle weighting method were introduced to correct misregistration of WFV-OLI image pair. The radiative transfer model was used to eliminate difference between OLI sensor and WFV1 camera through the spectral match factor (SMF). The near-infrared band of WFV1 camera encompasses water vapor absorption bands, thus a Look Up Table (LUT) for SMF varies from water vapor amount is established to estimate the water vapor effects. The surface synchronization experiment was designed to verify the reliability of the cross-calibration coefficients, which seem to perform better than the official coefficients claimed by the China Centre for Resources Satellite Data and Application (CCRSDA).

Compact blackbody calibration sources for in-flight calibration of spaceborne infrared instruments

Science.gov (United States)

Scheiding, S.; Driescher, H.; Walter, I.; Hanbuch, K.; Paul, M.; Hartmann, M.; Scheiding, M.

2017-11-01

High-emissivity blackbodies are mandatory as calibration sources in infrared radiometers. Besides the requirements on the high spectral emissivity and low reflectance, constraints regarding energy consumption, installation space and mass must be considered during instrument design. Cavity radiators provide an outstanding spectral emissivity to the price of installation space and mass of the calibration source. Surface radiation sources are mainly limited by the spectral emissivity of the functional coating and the homogeneity of the temperature distribution. The effective emissivity of a "black" surface can be optimized, by structuring the substrate with the aim to enlarge the ratio of the surface to its projection. Based on the experiences of the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) calibration source MBB3, the results of the surface structuring on the effective emissivity are described analytically and compared to the experimental performance. Different geometries are analyzed and the production methods are discussed. The high-emissivity temperature calibration source features values of 0.99 for wavelength from 5 μm to 10 μm and emissivity larger than 0.95 for the spectral range from 10 μm to 40 μm.

CR-39 and Lexan calibrated as low-LET radiation dosimeter, for three Mexican irradiation facilities

International Nuclear Information System (INIS)

Tavera, L.; Balcazar, M.; Matamoros, H.; Carrasco, H.

2005-01-01

An experimental calibration of two common nuclear track detectors, CR-39 and Lexan, for gamma and electrons radiation, was performed using various irradiation facilities. The dose response was obtained as a function of two parameters, the bulk etch rate and the UV absorbance for a wide dose range from 10 to 1000 kGy. The bulk etch rate sensitivity, for gamma and electrons, in CR-39 detector is higher than for Lexan detector. Lexan has a well-defined UV absorbance spectrum, but presents saturation for doses higher than 500 kGy, the same saturation characteristic is observed for the corresponding bulk etch rate response. For electron and gamma radiation, CR-39 shows a good response for doses from 10 kGy up to 1000 kGy, where data fit well an exponential curve for electrons and a lineal curve for gamma radiation

Calibration of "Babyline" RP instruments

CERN Multimedia

2015-01-01

  If you have old RP instrumentation of the “Babyline” type, as shown in the photo, please contact the Radiation Protection Group (Joffrey Germa, 73171) to have the instrument checked and calibrated. Thank you. Radiation Protection Group

Beta calibration and dosimetry at IPEN

International Nuclear Information System (INIS)

Caldas, L.V.E.

1983-01-01

A commercial extrapolation chamber (PTW, Germany) was tested in different beta radiation fields and its properties investigated. Its usefullness for beta radiation calibration and dosimetry was demonstrated. (Author) [pt

Calibration Laboratory of the Paul Scherrer Institute

International Nuclear Information System (INIS)

Gmuer, K.; Wernli, C.

1994-01-01

Calibration and working checks of radiation protection instruments are carried out at the Calibration Laboratory of the Paul Scherrer Institute. In view of the new radiation protection regulation, the calibration laboratory received an official federal status. The accreditation procedure in cooperation with the Federal Office of Metrology enabled a critical review of the techniques and methods applied. Specifically, personal responsibilities, time intervals for recalibration of standard instruments, maximum permissible errors of verification, traceability and accuracy of the standard instruments, form and content of the certificates were defined, and the traceability of the standards and quality assurance were reconsidered. (orig.) [de

Health Physics Society program for accreditation of calibration laboratories

International Nuclear Information System (INIS)

West, L.; Masse, F.X.; Swinth, K.L.

1988-01-01

The Health Physics Society has instituted a new program for accreditation of organizations that calibrate radiation survey instruments. The purpose of the program is to provide radiation protection professionals with an expanded means of direct and indirect access to national standards, thus introducing a means for improving the uniformity, accuracy, and quality of ionizing radiation field measurements. Secondary accredited laboratories are expected to provide a regional support basis. Tertiary accredited laboratories are expected to operate on a more local basis and provide readily available expertise to end users. The accreditation process is an effort to provide better measurement assurance for surveys of radiation fields. The status of the accreditation program, general criteria, gamma-ray calibration criteria, and x-ray calibration criteria are reviewed

Radioactive standards and calibration methods for contamination monitoring instruments

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Makoto [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-06-01

Contamination monitoring in the facilities for handling unsealed radioactive materials is one of the most important procedures for radiation protection as well as radiation dose monitoring. For implementation of the proper contamination monitoring, radiation measuring instruments should not only be suitable to the purpose of monitoring, but also be well calibrated for the objective qualities of measurement. In the calibration of contamination monitoring instruments, quality reference activities need to be used. They are supplied in different such as extended sources, radioactive solutions or radioactive gases. These reference activities must be traceable to the national standards or equivalent standards. On the other hand, the appropriate calibration methods must be applied for each type of contamination monitoring instruments. In this paper, the concepts of calibration for contamination monitoring instruments, reference sources, determination methods of reference quantities and practical calibration methods of contamination monitoring instruments, including the procedures carried out in Japan Atomic Energy Research Institute and some relevant experimental data. (G.K.)

Present status of calibration system and implementation of the new ICRU operational quantities in China

International Nuclear Information System (INIS)

Zhang Qingli

1995-01-01

Accompanying the wide use of ionizing radiation, general public have gradually become aware of the detriments of ionizing radiation. The adequate calibration standards, calibration facilities and calibration techniques, and the proper use of radiation-measuring instruments are the key steps of the measurements. In China, national standards are maintained by the National Institute of Metrology. The secondary standards including standard reference radiation sources, standard reference instruments and calibration phantoms in the Secondary Standard Dose Laboratory (SSDL) and other main calibration services are calibrated directly and periodically with the national (primary) standards. ICRU dose equivalent standards are established, and the calibration procedures being followed are consistent with the suggestions of International Standard Organization. γ ray and X-ray calibration facilities are explained. Since the issue of ICRU Report 39, ambient dose equivalent and directional dose equivalent for area monitoring and individual dose equivalent, penetrating and superficial, have been introduced. The concepts of quality assurance in radiation monitoring have been introduced. (K.I.)

A novel device for automatic withdrawal and accurate calibration of 99m-technetium radiopharmaceuticals to minimise radiation exposure to nuclear medicine staff and patient

International Nuclear Information System (INIS)

Nazififard, M.; Mahdizadeh, S.; Meigooni, A. S.; Alavi, M.; Suh, K. Y.

2012-01-01

A Joint Automatic Dispenser Equipment (JADE) has been designed and fabricated for automatic withdrawal and calibration of radiopharmaceutical materials. The thermoluminescent dosemeter procedures have shown a reduction in dose to the technician's hand with this novel dose dispenser system JADE when compared with the manual withdrawal of 99m Tc. This system helps to increase the precision of calibration and to minimise the radiation dose to the hands and body of the workers. This paper describes the structure of this device, its function and user-friendliness, and its efficacy. The efficacy of this device was determined by measuring the radiation dose delivered to the hands of the nuclear medicine laboratory technician. The user-friendliness of JADE has been examined. The automatic withdrawal and calibration offered by this system reduces the dose to the technician's hand to a level below the maximum permissible dose stipulated by the international protocols. This research will serve as a backbone for future study about the safe use of ionising radiation in medicine. (authors)

Control console of the gamma calibration room

International Nuclear Information System (INIS)

Vilchis P, A.E.; Romero G, M.

1999-01-01

The Nuclear Centre of Mexico has a Ionizing Radiation Metrology Center (CMRI). This is in charge of the calibration in Mexico and Latin America of equipment dedicated to radiation measurement as industrial, medical as other fields. The importance to ensure that the equipment stay justly calibrated, it is imposed the necessity of automating the different rooms which the CMRI has. in this case it will be exposed the Calibration room for gamma radiation type. The operation of this application was carried out with the LabVIEW development platform and also in C language. The hardware associated is: personal computer with two cards using the 8255 device, 16 channels with optical isolation to manage input/output TTL type, 16 channels with optical isolation to management of charges to 127 V a.c., and 2 channels for 90V d.c. motors. (Author)

A review of the probabilistic safety assessment of the Radiation Monitor Calibration Laboratory of the Almirante Alvaro Alberto Power Plant

International Nuclear Information System (INIS)

Gomes, Erica Cupertino

2005-03-01

The main purpose of this work is to update the PSA study of the Radiation Monitor Calibration Laboratory of the Almirante Alvaro Alberto Power Station taking into account new information. It is considered in this study an evaluation of the human reliability analysis in the calibration procedure of the radiation monitors, and for such the THERP modeling is used, as well as the use of the Bayesian approach for the calculation of the equipment failure probabilities used by the operators. Some accident scenarios of external origin were incorporated for evaluating their importance for an accident that might expose a worker to gamma radiation. A catastrophic failure is analyzed in the diesel generators 3 and 4, whose building is nearby the laboratory, as well as the route of change and the transportation of the steam generator of the nuclear power plant since the laboratory is located in the plant controlled area. Although more accidents scenarios are considered in this work, a conservative approach was not used and thus a smaller radiological risk was obtained. (author)

Development and calibration of a routine dosimetry system for radiation processing

International Nuclear Information System (INIS)

Ferreira, Danilo Cardenuto

2013-01-01

The development and calibration of a routine dosimetry system based on commercial, low cost photodiode (SFH 206) are presented in this work. The dosimeter probe was designed to operate unbiased in the direct current mode. The radiations were performed with Cobalt-60 Panoramic Irradiator facility in the dose-rate range of 8.1 Gy/h - 125 Gy/h. The photocurrents generated in the device, in each dose-rate, were registered with a digital electrometer and stored during the exposure time. The current response of the diode was measured as a function of the time in steps from 1 Gy up to 200 Gy with accumulated dose up to 15 kGy. In this range, the dose-response of the diode, given by the charge as function of dose, was linear with correlation coefficient better than 0.998. These results were compared with those obtained using Gafchromic film dosimetry often used in routine. To monitor possible gamma radiation effects produced on the diode, the current and charge sensitivities were measured as a function of the absorbed dose. For doses up to 15 kGy, it was not observed any radiation damage what confirms the reproducibility of the diode response better than 3 %. Finally, due to the small experimental errors ( 5% ) and good spatial resolution of the diode it was possible to measure the transit dose due to the movement of the Cobalt-60 radioactive source as well the dose rate mapping in the Panoramic Irradiator. (author)

Study of the performance of diagnostic radiology instruments during calibration

International Nuclear Information System (INIS)

Freitas, Rodrigo N. de; Vivolo, Vitor; Potiens, Maria da Penha A.

2008-01-01

Full text: The instruments used in diagnostic radiology measurements represent 8 % of the tested instruments by the calibration laboratory of IPEN annually (approximately 1600 in 2007). Considering that the calibration of this kind of instrument is performed biannually it is possible to conclude that almost 300 instruments are being used to measure the air kerma in diagnostic radiology clinics to determine the in beam values (in front of the patient), attenuated measurements (behind the patient) and scattered radiation. This work presents the results of the calibration of the instruments used in mammography, computed tomography, dental and conventional diagnostic radiology dosimetry, performed during the period of 2005 to 2007. Their performances during the calibrations measurements were evaluated. Although at the calibration laboratory there are three available series of radiation quality to this type of calibration (RQR, N and M, according to standards IEC 61267 and ISO 4037-1.), the applications can be assorted (general radiology, computed tomography, mammography, radiation protection and fluoroscopy). Depending on its design and behaviour , one kind of instrument can be used for one or more type of applications. The instruments normally used for diagnostic radiology measurements are ionization chambers with volumes varying from 3 to 1800 cm 3 , and can be cylindrical, spherical or plane parallel plates kind. They usually are sensitive to photon particles, with energies greater than 15 keV and can be used up to 1200 keV. In this work they were tested in X radiation fields from 25 to 150 kV, in specific qualities depending on the utilization of the instrument. The calibration results of 390 instruments received from 2005 to 2007 were analyzed. About 20 instruments were not able to be calibrated due to bad functioning. The calibration coefficients obtained were between 0.88 and 1.24. The uncertainties were always less than ± 3.6% to instruments used in scattered

Characterization of a 137Cs standard source for calibration purposes at CRCN-NE

International Nuclear Information System (INIS)

Oliveira, Mercia L.; Santos, Marcus A.P. dos; Benvides, Clayton A.

2008-01-01

Radiation protection monitoring instruments should be calibrated by accredited calibration laboratories. To offer calibration services, a laboratory must accomplish all requirements established by the national regulatory agency. The Calibration Service of the Centro Regional de Ciencias Nucleares (CRCN-NE), Comissao Nacional de Energia Nuclear, Recife, Brazil, is trying to achieve this accreditation. In the present work, a 137 Cs standard source was characterized following the national and international recommendations and the results are presented. This source is a commercially available single source irradiator model 28-8A, manufactured by J.L. Shepherd and Associates, with initial activity of 444 GBq (05/13/03). To provide different air kerma rates, as required for the calibration of portable radiation monitors, this irradiator have a set of four lead attenuators with different thickness, providing attenuation factors equal to 2, 4, 10 and 100 times (nominally). The performed tests included: size and uniformity of the radiation standard field at calibration reference position, variation of the air kerma rate for different lead attenuators, determination of attenuation factors for each lead attenuator configuration, and determination of the radiation scattering at the calibration reference position. The results showed the usefulness of the 137 Cs standard source for the calibration of radiation protection monitoring detectors. (author)

U.S. Department of Energy Office of Legacy Management Calibration Facilities - 12103

Energy Technology Data Exchange (ETDEWEB)

Barr, Deborah [U.S. Department of Energy Office of Legacy Management, Grand Junction, Colorado (United States); Traub, David; Widdop, Michael [S.M. Stoller Corporation, Grand Junction, Colorado (United States)

2012-07-01

This paper describes radiometric calibration facilities located in Grand Junction, Colorado, and at three secondary calibration sites. These facilities are available to the public for the calibration of radiometric field instrumentation for in-situ measurements of radium (uranium), thorium, and potassium. Both borehole and hand-held instruments may be calibrated at the facilities. Aircraft or vehicle mounted systems for large area surveys may be calibrated at the Grand Junction Regional Airport facility. These calibration models are recognized internationally as stable, well-characterized radiation sources for calibration. Calibration models built in other countries are referenced to the DOE models, which are also widely used as a standard for calibration within the U.S. Calibration models are used to calibrate radiation detectors used in uranium exploration, remediation, and homeland security. (authors)

The NRPB Chilton Calibration Laboratory for radiological protection measurements

International Nuclear Information System (INIS)

Iles, W.J.

1982-01-01

The Calibration Laboratory in NRPB Headquarters is intended as an authoritative reference laboratory for all aspects of radiation protection level instrument calibrations for X-, gamma and beta radiations and to be complementary to the national primary standards of the National Physical Laboratory. The gamma ray, filtered X-ray, fluorescence X-ray and beta ray facilities are described. (U.K.)

Calibration of a special neutron dosemeter based on solid-state track detectors and fission radiators in various neutron fields

International Nuclear Information System (INIS)

Doerschel, B.; Krusche, M.; Schuricht, V.

1980-01-01

The calibration of a personnel neutron dosemeter in different neutron fields is described. The badge-like dosemeter contains 5 detectors: polycarbonate foil (10 μm, Makrofol KG), 232 Th, natural uranium, natural uranium with boron, and natural uranium with cadmium. Detector sensitivity and calibration factors have been calculated and measured in radiation fields of 252 Cf fission neutrons, WWR-S reactor neutrons with and without Cd and Fe shielding, 3-MeV (d,t) generator neutrons, and 238 PuBe neutrons. Measurement range and achievable accuracy are discussed from the point of view of applying the dosemeter in routine and emergency uses

Dosimetry and Calibration Section

International Nuclear Information System (INIS)

Otto, T.

1998-01-01

The two tasks of the Dosimetry and Calibration Section at CERN are the Individual Dosimetry Service which assures the personal monitoring of about 5000 persons potentially exposed to ionizing radiation at CERN, and the Calibration Laboratory which verifies all the instruments and monitors. This equipment is used by the sections of the RP Group for assuring radiation protection around CERN's accelerators, and by the Environmental Section of TISTE. In addition, nearly 250 electronic and 300 quartz fibre dosimeters, employed in operational dosimetry, are calibrated at least once a year. The Individual Dosimetry Service uses an extended database (INDOS) which contains information about all the individual doses ever received at CERN. For most of 1997 it was operated without the support of a database administrator as the technician who had assured this work retired. The Software Support Section of TIS-TE took over the technical responsibility of the database, but in view of the many other tasks of this Section and the lack of personnel, only a few interventions for solving immediate problems were possible

Calibration of dosimeters at 80-120 keV electron irradiation

DEFF Research Database (Denmark)

Miller, A.; Helt-Hansen, J.

to calibrate thin-film dosimeters (Risø B3 and alanine films) by irradiation at the 80–120 keV electron accelerators. This calibration was compared to a 10MeV calibration, and we show that the radiation response of the dosimeter materials (the radiation chemical yield) is constant at these irradiation energies....... However, dose gradients within the dosimeters, when it is irradiated at low electron energies,mean that calibration function here will depend on both irradiation energy and the required effective point of measurement of the dosimeter. These are general effects that apply to any dosimeter that has a non...

NOAA Climate Data Record (CDR) of Intersatellite Calibrated Clear-Sky High Resolution Infrared Radiation Sounder (HIRS) Channel 12 Brightness Temperature Version 3

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The High-Resolution Infrared Radiation Sounder (HIRS) of intersatellite calibrated channel 12 brightness temperature (TB) product is a gridded global monthly time...

Accuracy and calibration of integrated radiation output indicators in diagnostic radiology: A report of the AAPM Imaging Physics Committee Task Group 190

International Nuclear Information System (INIS)

Lin, Pei-Jan P.; Schueler, Beth A.; Balter, Stephen; Strauss, Keith J.; Wunderle, Kevin A.; LaFrance, M. Terry; Kim, Don-Soo; Behrman, Richard H.; Shepard, S. Jeff; Bercha, Ishtiaq H.

2015-01-01

Due to the proliferation of disciplines employing fluoroscopy as their primary imaging tool and the prolonged extensive use of fluoroscopy in interventional and cardiovascular angiography procedures, “dose-area-product” (DAP) meters were installed to monitor and record the radiation dose delivered to patients. In some cases, the radiation dose or the output value is calculated, rather than measured, using the pertinent radiological parameters and geometrical information. The AAPM Task Group 190 (TG-190) was established to evaluate the accuracy of the DAP meter in 2008. Since then, the term “DAP-meter” has been revised to air kerma-area product (KAP) meter. The charge of TG 190 (Accuracy and Calibration of Integrated Radiation Output Indicators in Diagnostic Radiology) has also been realigned to investigate the “Accuracy and Calibration of Integrated Radiation Output Indicators” which is reflected in the title of the task group, to include situations where the KAP may be acquired with or without the presence of a physical “meter.” To accomplish this goal, validation test protocols were developed to compare the displayed radiation output value to an external measurement. These test protocols were applied to a number of clinical systems to collect information on the accuracy of dose display values in the field

Accuracy and calibration of integrated radiation output indicators in diagnostic radiology: A report of the AAPM Imaging Physics Committee Task Group 190

Energy Technology Data Exchange (ETDEWEB)

Lin, Pei-Jan P., E-mail: Pei-Jan.Lin@vcuhealth.org [Virginia Commonwealth University Medical Center, Richmond, Virginia 23298 (United States); Schueler, Beth A. [Mayo Clinic, Rochester, Minnesota 55905 (United States); Balter, Stephen [Columbia University Medical Center, New York, New York 10032 (United States); Strauss, Keith J. [Children’s Hospital Medical Center, Cincinnati, Ohio 45229 (United States); Wunderle, Kevin A. [Cleveland Clinic Foundation, Cleveland, Ohio 44195 (United States); LaFrance, M. Terry [Baystate Health Systems, Inc., Springfield, Massachusetts 01199 (United States); Kim, Don-Soo [Children’s Hospital Boston, Boston, Massachusetts 02115 (United States); Behrman, Richard H. [Boston University Medical Center, Boston, Massachusetts 02118 (United States); Shepard, S. Jeff [University of Texas MD Anderson Cancer Center, Houston, Texas 77096 (United States); Bercha, Ishtiaq H. [Children’s Hospital Colorado, Aurora, Colorado 80045 (United States)

2015-12-15

Due to the proliferation of disciplines employing fluoroscopy as their primary imaging tool and the prolonged extensive use of fluoroscopy in interventional and cardiovascular angiography procedures, “dose-area-product” (DAP) meters were installed to monitor and record the radiation dose delivered to patients. In some cases, the radiation dose or the output value is calculated, rather than measured, using the pertinent radiological parameters and geometrical information. The AAPM Task Group 190 (TG-190) was established to evaluate the accuracy of the DAP meter in 2008. Since then, the term “DAP-meter” has been revised to air kerma-area product (KAP) meter. The charge of TG 190 (Accuracy and Calibration of Integrated Radiation Output Indicators in Diagnostic Radiology) has also been realigned to investigate the “Accuracy and Calibration of Integrated Radiation Output Indicators” which is reflected in the title of the task group, to include situations where the KAP may be acquired with or without the presence of a physical “meter.” To accomplish this goal, validation test protocols were developed to compare the displayed radiation output value to an external measurement. These test protocols were applied to a number of clinical systems to collect information on the accuracy of dose display values in the field.

Calibration method for a in vivo measurement system using mathematical simulation of the radiation source and the detector; Metodo de calibracao de um sistema de medida in vivo atraves da simulacao matematica da fonte de radiacao e do detector

Energy Technology Data Exchange (ETDEWEB)

Hunt, John

1998-12-31

A Monte Carlo program which uses a voxel phantom has been developed to simulate in vivo measurement systems for calibration purposes. The calibration method presented here employs a mathematical phantom, produced in the form of volume elements (voxels), obtained through Magnetic Resonance Images of the human body. The calibration method uses the Monte Carlo technique to simulate the tissue contamination, the transport of the photons through the tissues and the detection of the radiation. The program simulates the transport and detection of photons between 0.035 and 2 MeV and uses, for the body representation, a voxel phantom with a format of 871 slices each of 277 x 148 picture elements. The Monte Carlo code was applied to the calibration of in vivo systems and to estimate differences in counting efficiencies between homogeneous and non-homogeneous radionuclide distributions in the lung. Calculations show a factor of 20 between deposition of {sup 241} Am at the back compared with the front of the lung. The program was also used to estimate the {sup 137} Cs body burden of an internally contaminated individual, counted with an 8 x 4 Nal (TI) detector and an {sup 241} Am body burden of an internally contaminated individual, who was counted using a planar germanium detector. (author) 24 refs., 38 figs., 23 tabs.

Transition Radiation Tracker calibration, searches beyond the Standard Model and multiparticle correlations in ATLAS

CERN Document Server

Alonso, Alejandro; Torsten, Akesson

This thesis contains two different aspects of my research work towards physics in proton-proton collisions in the ATLAS experiment at the LHC. The first part is focused on the understanding and developing of a calibration system to obtain the best possible charged particle reconstruction in the Transition Radiation Tracker. The method explained in this thesis is the current calibration technique used in the TRT and it is applied to all the data collected by ATLAS. Thanks to the method developed, the detector design resolution is achieved, and even improved in the central region of the TRT. In the second part, three different analyses are presented. Due to my interest in tracking and thanks to the new energy range available at the LHC, the first analysis is the study of multiparticle correlations at 900 GeV and 7 TeV. This analysis is performed with the first ATLAS data collected during 2010. Two different aspects are studied: the high order moments and an attempt to measure the normalized factorial moments ...

Calibration of fisheye lenses for hemispherical photography

International Nuclear Information System (INIS)

Diaci, J.; Kolar, U.

2000-01-01

Hemispherical photography represents one of the most appropriate methods of estimating averages of solar radiation over extended periods of time. This method is based upon the use of extremely wide-angle fisheye lenses, which produce large projection distortion. To correctly interpret hemispherical photography we have to know the projection characteristics of the fisheye lens in combination with a camera body. This can be achieved through lens calibration. The first part of the article explains in detail the calibration method for fisheye lenses which are used to assess the solar radiation in forest ecology research. In the second part the results of calibration for fisheye lens Sigma 8 mm, f/4 (MF, N) are presented. The lens was used on a Nikon F50 camera body

Calibration curves for biological dosimetry

International Nuclear Information System (INIS)

Guerrero C, C.; Brena V, M. . E-mail cgc@nuclear.inin.mx

2004-01-01

The generated information by the investigations in different laboratories of the world, included the ININ, in which settles down that certain class of chromosomal leisure it increases in function of the dose and radiation type, has given by result the obtaining of calibrated curves that are applied in the well-known technique as biological dosimetry. In this work is presented a summary of the work made in the laboratory that includes the calibrated curves for gamma radiation of 60 Cobalt and X rays of 250 k Vp, examples of presumed exposure to ionizing radiation, resolved by means of aberration analysis and the corresponding dose estimate through the equations of the respective curves and finally a comparison among the dose calculations in those people affected by the accident of Ciudad Juarez, carried out by the group of Oak Ridge, USA and those obtained in this laboratory. (Author)

Optimization of protection and calibration of the moisture-density gages troxler

International Nuclear Information System (INIS)

RAKOTONDRAVANONA, J.E.

2011-01-01

The purpose of this work is the implementation of the principle of optimization of the protection and calibration of moisture-density gages TROXLER. The main objectives are the application of radiation protection and the feasibility of a calibration laboratory design. The calibration of density and moisture may confirm the calibration of moisture-density gages TROXLER. The calibration of density consists of the assembly of measurements on three calibration blocks (magnesium, aluminium and magnesium/aluminium) built in the TRACKER. The value of density uncertainty is ±32 Kg.m -3 . The calibration of moisture is carried out on two calibration blocks (magnesium and magnesium/polyethylene)The value of moisture uncertainty is ±16 Kg.m -3 . The design of the laboratory returns to the dose limitation. The laboratory is designed mainly wall out of ordinary concrete, a good attenuator of the gamma radiations and neutron. For the design, the value of term source gamma is 25.77±0.20μSv.h -1 and the value of term source neutron is 7.88±0.35μSv.h -1 are used for the thickness of the walls. The importance of the design makes it possible to attenuate to the maximum doses and rates dose until the total absorption of the radiations. [fr

Calibration of SAR probes in waveguide at 900 MHz

International Nuclear Information System (INIS)

Jokela, K.; Puranen, L.; Hyysalo, P.

1998-01-01

The radiation safety tests for hand-held mobile phones require precise calibration of the small electric field probes used for the measurement of SAR in phantoms simulating the human body. In this study a calibration based on a rectangular waveguide was developed for SAR calibrations at 900 MHz

EMISAR: An Absolutely Calibrated Polarimetric L- and C-band SAR

DEFF Research Database (Denmark)

Christensen, Erik Lintz; Skou, Niels; Dall, Jørgen

1998-01-01

calibration. Accurately measured antenna gains and radiation patterns are included in the calibration. The processing system is developed to support data calibration, which is the key to most of the current applications. Recent interferometric enhancements are important for many scientific applications...

Single-source gamma radiation procedures for improved calibration and measurements in porous media

International Nuclear Information System (INIS)

Oostrom, M.; Hofstee, C.; Dane, H.; Lenhard, R.J.

1998-01-01

When dual-energy gamma radiation systems are employed for measurements in porous media, count rates from both sources are often used to compute parameter values. However, for several applications, the count rates of just one source are insufficient. These applications include the determination of volumetric liquid content values in two-liquid systems and salt concentration values in water-saturated porous media. Single-energy gamma radiation procedures for three applications are described in this paper. Through an error analysis, single-source procedures are shown to reduce the probable error in the determinations considerably. Example calculations and simple column experiments were conducted for each application to compare the performance of the new single-source and standard dual-source methods. In all cases, the single-source methods provided more reliable data than the traditional dual-source methods. In addition, a single-source calibration procedure is proposed to determine incident count rates indirectly. This procedure, which requires packing under saturated conditions, can be used in all single- and dual-source applications and yields accurate porosity and dry bulk density values

Calibration of AXAF Mirrors Using Synchrotron Radiation

Science.gov (United States)

Graessle, D. E.; Fitch, J.; Harris, B.; Hsieh, P.; Nguyen, D.; Hughes, J.; Schwartz, D.; Blake, R.

1995-12-01

Over the past five years, the SAO AXAF Mission Support Team has been developing methods and systems to provide a tunable, narrow-energy-bandwidth calibration of the reflecting efficiency of the AXAF High Resolution Mirror Assembly. A group of synchrotron beamlines at the National Synchrotron Light Source was selected for this calibration. Measurements and analysis are now available for the 2-12 keV energy range. An X-ray beam with energy purity E/Delta E ~ 5000 has been used to calibrate several witness flats which were coated simultaneously with elements of the flight mirror. In the iridium-edge range, (2010-3200 eV), these may be the first measurements ever to be reported. Optical constants for the iridium have been derived from a fit of reflectance versus grazing angle to a Fresnel equation model for the 2-12 keV energy range. The eight AXAF HRMA elements are being coated individually; however reflectance results are quite consistent from coating run to coating run for the first few pieces. The measurement precision is approximately 0.2%-0.4%. Residuals of the fit are nearly always within 1.0% of the data values, in the angle ranges of interest to AXAF.

Sistema de Reconocimiento de Caracteres Orientado a Sistemas Android

OpenAIRE

Segura Morales, Oriol; Universitat Autònoma de Barcelona. Escola d'Enginyeria

2014-01-01

Este proyecto trata sobre un sistema de reconocimiento de caracteres que se implementa para sistemas Android en forma de aplicación para móvil y Tablet. La aplicación está orientada para que los niños aprendan a escribir de una forma más amena. El sistema utiliza el patrón de diseño Modelo-Vista-Controlador para separar la lógica del sistema de la interfaz visual. En la interfaz, el sistema pide que se escriba un carácter utilizando la pantalla táctil y una vez el usuario lo ha escrito el sis...

Laboratory for Calibration of Gamma Radiation Measurement Instruments (LabCal) of Institute of Chemical, Biological, Radiological and Nuclear Defense (IDQBRN) from Brazilian Army Technology Center (CTEx); Laboratorio de Calibracao de Instrumentode Medicao de Radiacao Gama (LabCal) do IDQBRN do CTEx

Energy Technology Data Exchange (ETDEWEB)

Amorim, Aneuri de; Balthar, Mario Cesar V.; Santos, Avelino; Vilela, Paulo Ricardo T. de; Oliveira, Luciano Santa Rita; Penha, Paulo Eduardo C. de Oliveira; Gonzaga, Roberto Neves; Andrade, Edson Ramos de; Oliveira, Celio Jorge Vasques de; Fagundes, Luiz Cesar S., E-mail: aneurideamorim@gmail.com [Centro Tecnologico do Exercito (DQBRN/CTEx), Rio de Janeiro, RJ (Brazil). Instituto de Defesa Quimica, Biologica, Radiologica e Nuclear

2016-07-01

This paper describes the calibration laboratory deployment steps (LABCAL) gamma ionizing radiation measuring instruments in the Army Technology Center, CTEx. Initially the calibration of radiation monitors will be held in the dosimetric quantity air kerma and operational quantity ambient dose equivalent H*(d). The LABCAL / CTEx has not yet authorized by CASEC / CNEN. This laboratory aims to calibrate the ionizing radiation instruments used by the Brazilian Army. (author)

Calibration and quality assurance for rounded leaf-end MLC systems

International Nuclear Information System (INIS)

Graves, Maria N.; Thompson, Antoinette V.; Martel, Mary K.; McShan, Daniel L.; Fraass, Benedick A.

2001-01-01

Multileaf collimator (MLC) systems are available on most commercial linear accelerators, and many of these MLC systems utilize a design with rounded leaf ends and linear motion of the leaves. In this kind of system, the agreement between the digital MLC position readouts and the light field or radiation field edges must be achieved with software, since the leaves do not move in a focused motion like that used for most collimator jaw systems. In this work we address a number of the calibration and quality assurance issues associated with the acceptance, commissioning, and routine clinical use of this type of MLC system. These issues are particularly important for MLCs used for various types of intensity modulated radiation therapy (IMRT) and small, conformal fields. For rounded leaf end MLCs, it is generally not possible to make both the light and radiation field edges agree with the digital readout, so differences between the two kinds of calibrations are illustrated in this work using one vendor's MLC system. It is increasingly critical that the MLC leaf calibration be very consistent with the radiation field edges, so in this work a methodology for performing accurate radiation field size calibration is discussed. A system external to the vendor's MLC control system is used to correct or handle limitations in the MLC control system. When such a system of corrections is utilized, it is found that the MLC radiation field size can be defined with an accuracy of approximately 0.3 mm, much more accurate than most vendor's specifications for MLC accuracy. Quality assurance testing for such a calibration correction system is also demonstrated

Calibration method for a in vivo measurement system using mathematical simulation of the radiation source and the detector

International Nuclear Information System (INIS)

Hunt, John

1998-01-01

A Monte Carlo program which uses a voxel phantom has been developed to simulate in vivo measurement systems for calibration purposes. The calibration method presented here employs a mathematical phantom, produced in the form of volume elements (voxels), obtained through Magnetic Resonance Images of the human body. The calibration method uses the Monte Carlo technique to simulate the tissue contamination, the transport of the photons through the tissues and the detection of the radiation. The program simulates the transport and detection of photons between 0.035 and 2 MeV and uses, for the body representation, a voxel phantom with a format of 871 slices each of 277 x 148 picture elements. The Monte Carlo code was applied to the calibration of in vivo systems and to estimate differences in counting efficiencies between homogeneous and non-homogeneous radionuclide distributions in the lung. Calculations show a factor of 20 between deposition of 241 Am at the back compared with the front of the lung. The program was also used to estimate the 137 Cs body burden of an internally contaminated individual, counted with an 8 x 4 Nal (TI) detector and an 241 Am body burden of an internally contaminated individual, who was counted using a planar germanium detector. (author)

Calibration of ALIBAVA readout system

Energy Technology Data Exchange (ETDEWEB)

Trofymov, Artur [DESY, Hamburg (Germany); Collaboration: ATLAS experiment-Collaboration

2015-07-01

The High Luminosity Large Hadron Collider (LH-LHC) is the upgrade of the LHC that foreseen to increase the instantaneous luminosity by a factor ten with a total integrated luminosity of 3000 fb{sup -1}. The ATLAS experiment will need to build a new tracker to operate in the new severe LH-LHC conditions (increasing detector granularity to cope with much higher channel occupancy, designing radiation-hard sensors and electronics to cope with radiation damage). Charge collection efficiency (CCE) of silicon strip sensors for the new ATLAS tracker can be done with ALIBAVA analog readout system (analog system gives more information about signal from all strips than digital). In this work the preliminary results of ALIBAVA calibration using two different methods (with ''source data'' and ''calibration data'') are presented. Calibration constant obtained by these methods is necessary for knowing collected charge on the silicon strip sensors and for having the ability to compare it with measurements done at the test beam.

On the current status of an ISO working document on the calibration and type testing of radiation protection dosemeters for photons

International Nuclear Information System (INIS)

Kramer, H.M.; Boehm, J.; Iles, W.J.; Thompson, I.M.G.

1994-01-01

In October 1992, Working Group 2 'Reference Radiations' of ISO TC85/SC2 'Nuclear Energy/Radiation Protection' officially prepared a first draft of a document with the working title: 'The Calibration of Individual and Area Dosimeters for Photon Radiation and the Determination of their Response as a Function of Photon Energy and Angle of Incidence'. On the basis of existing ISO Standards 4037 'X and γ Reference Radiations ...' and ISO 8963 'Dosimetry of X and γ Reference Radiations ...' and the recent updating of these standards, a first draft of the new working document has been prepared. An overview of its contents is presented, an account of some of the topics as yet open is given and some new data pertinent to this future standard are included. (Author)

Calibration of clinical dosemeters in the IAEA water phantom

International Nuclear Information System (INIS)

Caldas, L.V.E.; Albuquerque, M.P.P.

1994-01-01

The procedures recommended by the IAEA Code of Practice were applied at the Calibration Laboratory of Sao Paulo in order to provide in the future the clinical dosemeters users with absorbed dose to water calibration factors for Cobalt 60 radiation beams. In this work the clinical dosemeters were calibrated free in air and in water, and the results were compared, using conversion factors. The several tested clinical dosemeters of different manufacturers and models belong to the laboratory and to hospitals. For the measurements in water the IAEA cubic water phantom was used. The dosemeters were all calibrated free in air in terms of air kerma, and the calibration factors in terms of absorbed dose to water were obtained through conversion factors. the same dosemeters were also calibrated into the water phantom. Good agreement was found between the two methods, the differences were always less than 0.5%. The data obtained during this work show that when the dosemeters are used only in Cobalt 60 radiation and the users apply in the hospital routine work the IAEA Code of Practice, the calibration can be performed directly in the water phantom. This procedure provides the useful calibration factors in terms of absorbed dose to water

Fourth IRMF comparison of calibrations of portable gamma-ray dose- rate monitors 2001-2002 Ionising radiation

CERN Document Server

Lewis, V E

2002-01-01

The Ionising Radiations Metrology Forum (IRMF) organised a fourth comparison of calibrations of gamma-ray dose-rate monitors in which fifteen establishments in the UK participated. The exercise involved the circulation of three gamma-ray monitors for calibration in the fields produced using sup 1 sup 3 sup 7 Cs, sup 2 sup 4 sup 1 Am and sup 6 sup 0 Co. The instruments used were an Electra with MC 20 probe, a Mini-Instruments Mini-rad 1000 and a Siemens electronic personal dosemeter Mk 2 (EPD). The responses relative to 'true' dose equivalent rate were calculated by the individual participants and submitted to the for analysis along with details of the facilities and fields employed. Details of the estimated uncertainties were also reported. The results are compared and demonstrate generally satisfactory agreement between the participating establishments. However, the participants' treatment of uncertainties needs improvement and demonstrates a need for guidance in this area.

Calibration of reference KAP-meters at SSDL and cross calibration of clinical KAP-meters

International Nuclear Information System (INIS)

Hetland, Per O.; Friberg, Eva G.; Oevreboe, Kirsti M.; Bjerke, Hans H.

2009-01-01

In the summer of 2007 the secondary standard dosimetry laboratory (SSDL) in Norway established a calibration service for reference air-kerma product meter (KAP-meter). The air-kerma area product, PKA, is a dosimetric quantity that can be directly related to the patient dose and used for risk assessment associated with different x-ray examinations. The calibration of reference KAP-meters at the SSDL gives important information on parameters influencing the calibration factor for different types of KAP-meters. The use of reference KAP-meters calibrated at the SSDL is an easy and reliable way to calibrate or verify the PKA indicated by the x-ray equipment out in the clinics. Material and methods. Twelve KAP-meters were calibrated at the SSDL by use of the substitution method at five diagnostic radiation qualities (RQRs). Results. The calibration factors varied from 0.94 to 1.18. The energy response of the individual KAP-meters varied by a total of 20% between the different RQRs and the typical chamber transmission factors ranged from 0.78 to 0.91. Discussion. It is important to use a calibrated reference KAP-meter and a harmonised calibration method in the PKA calibration in hospitals. The obtained uncertainty in the PKA readings is comparable with other calibration methods if the information in the calibration certificate is correct used, corrections are made and proper positioning of the KAP-chamber is performed. This will ensure a reliable estimate of the patient dose and a proper optimisation of conventional x-ray examinations and interventional procedures

The ENEA calibration service for ionising radiations. Part 1: Photons; Il centro di taratura per la radiazioni ionizzanti di Bologna. Parte 1: Fotoni

Energy Technology Data Exchange (ETDEWEB)

Monteventi, F.; Sermenghi, I. [ENEA Centro Ricerche Ezio Clementel, Bologna (Italy). Dipt. Ambiente

1999-07-01

The ENEA (National Agency for New Technology, Energy and the Environment) calibration service for ionizing radiations has been active for 40 years in the secondary standard dosimetry laboratory web. It has been the first center, in 1985, to be acknowledges by the Italian calibration service (SIT) for the two quantities for photons: exposure and air kerma. Since the Institute for the Radiation Protection of ENEA has moved to the new site in Montecuccolino (Bologna, Italy) in 1995, the whole laboratory has been renovated and all irradiation rooms together with radiation source and equipment have been reorganized according to the {chi}, {gamma}, {beta} and neutron fields metrology requirements. The aim of this report, as the first part of a report describing all facilities available at the service, is to give a detailed description of all equipment s qualified for photon fields metrology including the secondary standards and the calibration procedures performed for radiation monitoring devices and dosemeters. [Italian] Il centro di taratura dell'ENEA di Bologna opera nel campo della metrologia secpndaria da quasi 40 anni ed e' stato il primo centro nel 1985 ad essere riconosciuto dal SIT (Servizio di Taratura in Italia) per le grandezze esposizione e Kerma in aria. Con l'insediamento di tutto l'Istituto per la Radioprotezione nella nuova sede di Montecuccolino sono state ricostruite e riorganizzate anche tutte le sale di irraggiamento e tutti gli impianti radiogeni a disposizione per la metrologia delle radiazioni X, gamma, beta e neutroni. Intenzione di questo primo rapporto e' descrivere le attrezzature qualificate per la metrologia fotonica, dei campioni di misura e delle procedure adottate per la taratura degli strumenti e dei dosimetri.

Local Adaptive Calibration of the GLASS Surface Incident Shortwave Radiation Product Using Smoothing Spline

Science.gov (United States)

Zhang, X.; Liang, S.; Wang, G.

2015-12-01

Incident solar radiation (ISR) over the Earth's surface plays an important role in determining the Earth's climate and environment. Generally, can be obtained from direct measurements, remotely sensed data, or reanalysis and general circulation models (GCMs) data. Each type of product has advantages and limitations: the surface direct measurements provide accurate but sparse spatial coverage, whereas other global products may have large uncertainties. Ground measurements have been normally used for validation and occasionally calibration, but transforming their "true values" spatially to improve the satellite products is still a new and challenging topic. In this study, an improved thin-plate smoothing spline approach is presented to locally "calibrate" the Global LAnd Surface Satellite (GLASS) ISR product using the reconstructed ISR data from surface meteorological measurements. The influences of surface elevation on ISR estimation was also considered in the proposed method. The point-based surface reconstructed ISR was used as the response variable, and the GLASS ISR product and the surface elevation data at the corresponding locations as explanatory variables to train the thin plate spline model. We evaluated the performance of the approach using the cross-validation method at both daily and monthly time scales over China. We also evaluated estimated ISR based on the thin-plate spline method using independent ground measurements at 10 sites from the Coordinated Enhanced Observation Network (CEON). These validation results indicated that the thin plate smoothing spline method can be effectively used for calibrating satellite derived ISR products using ground measurements to achieve better accuracy.

System for calibration of SPEAR transport line toroids

International Nuclear Information System (INIS)

Huang, T.V.; Smith, H.; Crook, K.

1977-01-01

A one nanosecond pulse generator was developed for calibration of the intensity monitors (toroids) in the SPEAR transport lines. The generator, located at the toroid, is simple, low cost and resistant to radiation. The generator and its connection to the standard SLAC toroid calibration system are described

Inclusion of time uncertainty in calibration of ionizing radiations

International Nuclear Information System (INIS)

Jordao, B.O.; Quaresma, D.S.; Carvalho, R.J.; Peixoto, J.G.P.

2014-01-01

In terms of metrology, two key factors for reliability employed in the calibration process are what we call Traceability and Uncertainty. Traceability will provide confidence in measurements. Already uncertainty will provide security and quality of what this being measured. Based on the above, this article suggests the implementation time of uncertainty in the calibration of radiological instruments thus increasing the reliability and traceability of the system. (author)

The Impact of Indoor and Outdoor Radiometer Calibration on Solar Measurements: Preprint

Energy Technology Data Exchange (ETDEWEB)

Habte, Aron; Sengupta, Manajit; Andreas, Afshin; Reda, Ibrahim; Robinson, Justin

2016-07-01

Accurate solar radiation data sets are critical to reducing the expenses associated with mitigating performance risk for solar energy conversion systems, and they help utility planners and grid system operators understand the impacts of solar resource variability. The accuracy of solar radiation measured by radiometers depends on the instrument performance specification, installation method, calibration procedure, measurement conditions, maintenance practices, location, and environmental conditions. This study addresses the effect of calibration methodologies and the resulting calibration responsivities provided by radiometric calibration service providers such as the National Renewable Energy Laboratory (NREL) and manufacturers of radiometers. Some of these radiometers are calibrated indoors, and some are calibrated outdoors. To establish or understand the differences in calibration methodology, we processed and analyzed field-measured data from these radiometers. This study investigates calibration responsivities provided by NREL's broadband outdoor radiometer calibration (BORCAL) and a few prominent manufacturers. The reference radiometer calibrations are traceable to the World Radiometric Reference. These different methods of calibration demonstrated 1% to 2% differences in solar irradiance measurement. Analyzing these values will ultimately assist in determining the uncertainties of the radiometer data and will assist in developing consensus on a standard for calibration.

Nimbus-7 Earth radiation budget calibration history. Part 1: The solar channels

Science.gov (United States)

Kyle, H. Lee; Hoyt, Douglas V.; Hickey, John R.; Maschhoff, Robert H.; Vallette, Brenda J.

1993-01-01

The Earth Radiation Budget (ERB) experiment on the Nimbus-7 satellite measured the total solar irradiance plus broadband spectral components on a nearly daily basis from 16 Nov. 1978, until 16 June 1992. Months of additional observations were taken in late 1992 and in 1993. The emphasis is on the electrically self calibrating cavity radiometer, channel 10c, which recorded accurate total solar irradiance measurements over the whole period. The spectral channels did not have inflight calibration adjustment capabilities. These channels can, with some additional corrections, be used for short-term studies (one or two solar rotations - 27 to 60 days), but not for long-term trend analysis. For channel 10c, changing radiometer pointing, the zero offsets, the stability of the gain, the temperature sensitivity, and the influences of other platform instruments are all examined and their effects on the measurements considered. Only the question of relative accuracy (not absolute) is examined. The final channel 10c product is also compared with solar measurements made by independent experiments on other satellites. The Nimbus experiment showed that the mean solar energy was about 0.1 percent (1.4 W/sqm) higher in the excited Sun years of 1979 and 1991 than in the quiet Sun years of 1985 and 1986. The error analysis indicated that the measured long-term trends may be as accurate as +/- 0.005 percent. The worse-case error estimate is +/- 0.03 percent.

Comparative study among calibration methods of clinical applicators of beta radiation

International Nuclear Information System (INIS)

Antonio, Patricia de Lara

2009-01-01

90 Sr+ 90 Y clinical applicators are instruments used in brachytherapy procedures and they have to be periodically calibrated, according to international standards and recommendations. In this work, four calibration methods of dermatological and ophthalmic applicators were studied, comparing the results with those given by the calibration certificates of the manufacturers. The methods included the use of the standard applicator of the Calibration Laboratory (LCI), calibrated by the National Institute of Standards and Technology; an Amersham applicator (LCI) as reference; a mini-extrapolation chamber developed at LCI as an absolute standard; and thermoluminescent dosimetry. The mini-extrapolation chamber and a PTW commercial extrapolation chamber were studied in relation to their performance through quality control tests of their response, as leakage current, repeatability and reproducibility. The distribution of the depth dose in water, that presents high importance in dosimetry of clinical applicators, was determined using the mini extrapolation chamber and the thermoluminescent dosimeters. The results obtained were considered satisfactory for the both cases, and comparable to the data of the IAEA (2002) standard. Furthermore, a dosimetry postal kit was developed for the calibration of clinical applicators using the thermoluminescent technique, to be sent to clinics and hospitals, without the need of the transport of the sources to IPEN for calibration. (author)

e-Calibrations: using the Internet to deliver calibration services in real time at lower cost

International Nuclear Information System (INIS)

Desrosiers, Marc; Nagy, Vitaly; Puhl, James; Glenn, Robert; Densock, Robert; Stieren, David; Lang, Brian; Kamlowski, Andreas; Maier, Diether; Heiss, Arthur

2002-01-01

The National Institute of Standards and Technology (NIST) is expanding into a new frontier in the delivery of measurement services. The Internet will be employed to provide industry with electronic traceability to national standards. This is a radical departure from the traditional modes of traceability and presents many new challenges. The traditional mail-based calibration service relies on sending artifacts to the user, who then mails them back to NIST for evaluation. The new service will deliver calibration results to the industry customer on-demand, in real-time, at a lower cost. The calibration results can be incorporated rapidly into the production process to ensure the highest quality manufacturing. The service would provide the US radiation processing industry with a direct link to the NIST calibration facilities and its expertise, and provide an interactive feedback process between industrial processing and the national measurement standard. Moreover, an Internet calibration system should contribute to the removal of measurement-related trade barriers

Automated Calibration of Dosimeters for Diagnostic Radiology

International Nuclear Information System (INIS)

Romero Acosta, A.; Gutierrez Lores, S.

2015-01-01

Calibration of dosimeters for diagnostic radiology includes current and charge measurements, which are often repetitive. However, these measurements are usually done using modern electrometers, which are equipped with an RS-232 interface that enables instrument control from a computer. This paper presents an automated system aimed to the measurements for the calibration of dosimeters used in diagnostic radiology. A software application was developed, in order to achieve the acquisition of the electric charge readings, measured values of the monitor chamber, calculation of the calibration coefficient and issue of a calibration certificate. A primary data record file is filled and stored in the computer hard disk. The calibration method used was calibration by substitution. With this system, a better control over the calibration process is achieved and the need for human intervention is reduced. the automated system will be used in the calibration of dosimeters for diagnostic radiology at the Cuban Secondary Standard Dosimetry Laboratory of the Center for Radiation Protection and Hygiene. (Author)

Calibrations and evaluation of the quality assurance during 1999 at the National Laboratory for ionising radiation; Kalibrerings- och normalieverksamheten vid Riksmaetplats 06 under 1999

Energy Technology Data Exchange (ETDEWEB)

Grindborg, Jan-Erik; Israelsson, Karl-Erik; Kylloenen, Jan-Erik; Samuelson, Goeran

2000-06-01

The Swedish Radiation Protection Institute is the National Laboratory for the dosimetric quantities kerma, absorbed dose and dose equivalent. The activity is based on established calibration procedures and a quality assurance program for the used standards. This report gives a brief summary of the calibrations performed during 1999 and a more detailed description and analysis of the quality assurance during this year. The report makes it easier to draw conclusions about the long-term stability and possible malfunctions.

PET/CT alignment calibration with a non-radioactive phantom and the intrinsic 176Lu radiation of PET detector

International Nuclear Information System (INIS)

Wei, Qingyang; Ma, Tianyu; Wang, Shi; Liu, Yaqiang; Gu, Yu; Dai, Tiantian

2016-01-01

Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic 176 Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic 176 Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

PET/CT alignment calibration with a non-radioactive phantom and the intrinsic 176Lu radiation of PET detector

Science.gov (United States)

Wei, Qingyang; Ma, Tianyu; Wang, Shi; Liu, Yaqiang; Gu, Yu; Dai, Tiantian

2016-11-01

Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic 176Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic 176Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

Automation of dosimeters calibration for radiotherapy in secondary dosimetric calibration laboratory of the CPHR; Automatizacion de la calibracion de dosimetros de radioterapia en el laboratorio secundario de calibracion dosimetrica del CPHR

Energy Technology Data Exchange (ETDEWEB)

Acosta, Andy L. Romero; Lores, Stefan Gutierrez, E-mail: c19btm@frcuba.co.cu [Centro de Proteccion e Higiene de las Radiaciones (CPHR), La Habana (Cuba)

2013-11-01

This paper presents the design and implementation of an automated system for measurements in the calibration of reference radiation dosimeters. It was made a software application that performs the acquisition of the measured values of electric charge, calculated calibration coefficient and automates the calibration certificate issuance. These values are stored in a log file on a PC. The use of the application improves control over the calibration process, helps to humanize the work and reduces personnel exposure. The tool developed has been applied to the calibration of dosimeters radiation patterns in the LSCD of the Centro de Proteccion e Higiene de las Radiaciones, Cuba.

Absolute calibration in vivo measurement systems

International Nuclear Information System (INIS)

Kruchten, D.A.; Hickman, D.P.

1991-02-01

Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. Absolute calibration of in vivo measurement systems will eliminate the need to generate a series of human surrogate structures (i.e., phantoms) for calibrating in vivo measurement systems. The absolute calibration of in vivo measurement systems utilizes magnetic resonance imaging (MRI) to define physiological structure, size, and composition. The MRI image provides a digitized representation of the physiological structure, which allows for any mathematical distribution of radionuclides within the body. Using Monte Carlo transport codes, the emission spectrum from the body is predicted. The in vivo measurement equipment is calibrated using the Monte Carlo code and adjusting for the intrinsic properties of the detection system. The calibration factors are verified using measurements of existing phantoms and previously obtained measurements of human volunteers. 8 refs

High-dose secondary calibration laboratory accreditation program

Energy Technology Data Exchange (ETDEWEB)

Humphreys, J.C. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

1993-12-31

There is a need for high-dose secondary calibration laboratories to serve the multi-billion dollar radiation processing industry. This need is driven by the desires of industry for less costly calibrations and faster calibration-cycle response time. Services needed include calibration irradiations of routine processing dosimeters and the supply of reference standard transfer dosimeters for irradiation in the production processing facility. In order to provide measurement quality assurance and to demonstrate consistency with national standards, the high-dose secondary laboratories would be accredited by means of an expansion of an existing National Voluntary Laboratory Accreditation Program. A laboratory performance criteria document is under development to implement the new program.

High-dose secondary calibration laboratory accreditation program

International Nuclear Information System (INIS)

Humphreys, J.C.

1993-01-01

There is a need for high-dose secondary calibration laboratories to serve the multi-billion dollar radiation processing industry. This need is driven by the desires of industry for less costly calibrations and faster calibration-cycle response time. Services needed include calibration irradiations of routine processing dosimeters and the supply of reference standard transfer dosimeters for irradiation in the production processing facility. In order to provide measurement quality assurance and to demonstrate consistency with national standards, the high-dose secondary laboratories would be accredited by means of an expansion of an existing National Voluntary Laboratory Accreditation Program. A laboratory performance criteria document is under development to implement the new program

Psiconeuroinmunología: Conexiones entre sistema nervioso y sistema inmune

Directory of Open Access Journals (Sweden)

García López, Luis Joaquín

2008-09-01

Full Text Available La psiconeuroinmunología es una nueva parcela de la ciencia que apenas lleva tres décadas, pero que en los últimos años ha sido objeto de una enorme atención por diversos grupos de investigación. El articulo pretende exponer brevemente cómo están organizados los sistemas inmune y neuroendocrino, para después presentar los hallazgos que hasta el momento intentan dar explicación de las relaciones entre ambos con el sistema nervioso, así como las influencias de unos sobre otros, más concretamente expresar la relación entre los tres sistemas responsables de la defensa del organismo y, más ampliamente, de su mantenimiento homeostático. Cuando se trata de amenazas, el sistema nervioso central tiene que decidir qué sistema se pone en marcha, el sistema de estrés como energía para el ataque o la huida (un animal que nos quiere atacar, el sistema inmune para neutralizar el antígeno (un virus que nos quiere atacar o ambos (la energía es necesaria también para el sistema inmune. Como parece ser que en muchas ocasiones la depresión aparece tras los esfuerzos infructuosos de puesta en marcha de estrategias de afrontamiento, también hemos repasado sucintamente algunas investigaciones que relacionan al sistema inmune con la depresión, así como con los trastornos del sueño. Se finaliza con las aportaciones que la psicología puede ofrecer a nivel terapéutico.

Individual dosimetry and calibration

International Nuclear Information System (INIS)

Hoefert, M.; Nielsen, M.

1996-01-01

In 1995 both the Individual Dosimetry and Calibration Sections worked under the condition of a status quo and concentrated fully on the routine part of their work. Nevertheless, the machine for printing the bar code which will be glued onto the film holder and hence identify the people when entering into high radiation areas was put into operation and most of the holders were equipped with the new identification. As far as the Calibration Section is concerned the project of the new source control system that is realized by the Technical Support Section was somewhat accelerated

Comparison of the uncertainties of several European low-dose calibration facilities

Science.gov (United States)

Dombrowski, H.; Cornejo Díaz, N. A.; Toni, M. P.; Mihelic, M.; Röttger, A.

2018-04-01

The typical uncertainty of a low-dose rate calibration of a detector, which is calibrated in a dedicated secondary national calibration laboratory, is investigated, including measurements in the photon field of metrology institutes. Calibrations at low ambient dose equivalent rates (at the level of the natural ambient radiation) are needed when environmental radiation monitors are to be characterised. The uncertainties of calibration measurements in conventional irradiation facilities above ground are compared with those obtained in a low-dose rate irradiation facility located deep underground. Four laboratories quantitatively evaluated the uncertainties of their calibration facilities, in particular for calibrations at low dose rates (250 nSv/h and 1 μSv/h). For the first time, typical uncertainties of European calibration facilities are documented in a comparison and the main sources of uncertainty are revealed. All sources of uncertainties are analysed, including the irradiation geometry, scattering, deviations of real spectra from standardised spectra, etc. As a fundamental metrological consequence, no instrument calibrated in such a facility can have a lower total uncertainty in subsequent measurements. For the first time, the need to perform calibrations at very low dose rates (< 100 nSv/h) deep underground is underpinned on the basis of quantitative data.

Standards in radiation protection at the IAEA Dosimetry Laboratory

International Nuclear Information System (INIS)

Czap, L.; Pernicka, F.; Matscheko, G.; Andreo, P.

1999-01-01

Approximately 90% of the Secondary Standard Dosimetry Laboratories (SSDLs) provide users with calibrations of radiation protection instruments, and the Agency is making every necessary effort to insure that SSDLs measurements in radiation protection are traceable to Primary Standards. The IAEA provides traceable calibrations of ionization chambers in terms of air kerma at radiation protection levels and ambient dose equivalent calibrations. SSDLs are encouraged to use the calibrations available from the Agency to provide traceability for their radiation protection measurements. Measurements on diagnostic X ray generators have become increasingly important in radiation protection and some SSDLs are involved in such measurements. The IAEA has proper radiation sources available to provide traceable calibrations to the SSDLs in this field, including an X ray unit specifically for mammography dedicated to standardization procedures. The different photon beam qualities and calibration procedures available in the Agency's Dosimetry Laboratory will be described. (author)

Calibration and validation of a quality assurance system for {sup 90}Sr/{sup 90}Y radiation source trains

Energy Technology Data Exchange (ETDEWEB)

Rosenthal, P [Department of Radiation Therapy and Oncology, Freie Universitaet Berlin, Benjamin Franklin University Medical Centre, Hindenburgdamm 30, D-12200 Berlin (Germany); Weber, W [Novoste GmbH, Huettenallee 237 c, D-47800 Krefeld (Germany); Foerster, A [Department of Radiation Therapy and Oncology, Freie Universitaet Berlin, Benjamin Franklin University Medical Centre, Hindenburgdamm 30, D-12200 Berlin (Germany); Orth, O [Department of Radiation Therapy and Oncology, Freie Universitaet Berlin, Benjamin Franklin University Medical Centre, Hindenburgdamm 30, D-12200 Berlin (Germany); Koehler, B [Department of Radiation Therapy and Oncology, Freie Universitaet Berlin, Benjamin Franklin University Medical Centre, Hindenburgdamm 30, D-12200 Berlin (Germany); Seiler, F [Department of Radiation Therapy and Oncology, Freie Universitaet Berlin, Benjamin Franklin University Medical Centre, Hindenburgdamm 30, D-12200 Berlin (Germany)

2003-03-07

A quality assurance system (OPTIDOS, PTW-Freiburg) developed for dose rate verification of {sup 90}Sr/{sup 90}Y radiation source trains (RSTs) was calibrated and validated. These source trains are used in the 5-F-BetaCath{sup TM} system (Novoste Corp.) for the treatment of endovascular diseases. The calibration factor of the OPTIDOS system was obtained empirically and is valid for {sup 90}Sr/{sup 90}Y dose rate measurements at the specification point which is located at 2 mm distance from the source axis. A total of 187 OPTIDOS dose rate verifications of the 5-F-BetaCath{sup TM} system were performed in different hospitals. The histogram of the deviation between the manufacturer's dose rate specification and the dose rate measured using the OPTIDOS dosimetry system is Gaussian shaped with {+-}3% relative width and a mean shift of about +2% with respect to the corresponding dose rate specification. Additionally, 128 OPTIDOS dose rate verifications of the new jacketed RST (3.5-F-BetaCath{sup TM}, Novoste Corp.) were performed using the same calibration factor as derived for the 5-F-BetaCath{sup TM} system. Distribution of the deviation between the certified and the measured dose rate is nearly identical in comparison to the histogram of the 5-F-BetaCath{sup TM} system. The mean value of the deviations is shifted by -1.5% with respect to the certified dose rate. In order to compare the results of the calibrated OPTIDOS dosimetry system with a standard measuring method, separate dose rate measurements were performed using electron accelerator calibrated radiochromic films in which calibration is traceable to PTB (Physikalisch Technische Bundesanstalt, Germany). Deviation between both the methods is less than 3.1%. These results confirm that the calibrated OPTIDOS dosimetry system can be considered suitable for quality assurance of both types of RST used in the BetaCath{sup TM} systems.

Investigation of the present management status of calibration source based on the law concerning prevention of radiation hazards due to radioisotopes

International Nuclear Information System (INIS)

Takahashi, Yasuyuki; Igarashi, Hiroshi; Hirano, Kunihiro; Kawaharada, Yasuhiro; Igarashi, Hitoshi; Murase, Ken-ya; Mochizuki, Teruhito

2007-01-01

An amendment concerning the enforcement of the law on the prevention of radiation hazards due to radioisotopes, etc., and the medical service law enforcement regulations were promulgated on June 1, 2005. This amendment concerned international basic safety standards and the sealing of radiation sources. Sealed radiation sources ≤3.7 MBq, which had been excluded from regulation, were newly included as an object of regulation. Investigation of the single photon emission computed tomography (SPECT) system instituted in hospitals indicated that almost all institutions adhere to the new amendment, and the calibration source, the checking source, etc., corresponding to this amendment were maintained appropriately. Any institutions planning to return sealed radioisotopes should refer to this report. (author)

Evaluation of Multiple-Sampling Function used with a Microtek flatbed scanner for Radiation Dosimetry Calibration of EBT2 Film

Energy Technology Data Exchange (ETDEWEB)

Chang, Liyun [Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung 82445, Taiwan (China); Ho, Sheng-Yow [Department of Nursing, Chang Jung Christian University, Tainan 71101, Taiwan (China); Department of Radiation Oncology, Chi Mei Medical Center, Liouying, Tainan 73657, Taiwan (China); Ding, Hueisch-Jy [Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung 82445, Taiwan (China); Hwang, Ing-Ming [Department of Medical Imaging and Radiology, Shu Zen College of Medicine and Management, Kaohsiung 82144, Taiwan (China); Chen, Pang-Yu, E-mail: pangyuchen@yahoo.com.tw [Department of Radiation Oncology, Sinlau Christian Hospital, Tainan 70142, Taiwan (China); Lee, Tsair-Fwu, E-mail: tflee@kuas.edu.tw [Medical Physics and Informatics Laboratory, Department of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan (China)

2016-10-01

The radiochromic EBT2 film is a widely used quality assurance device for radiation therapy. This study evaluated the film calibration performance of the multiple-sampling function, a function of the ScanWizard Pro scanning software provided by the manufacturer, when used with Microtek 9800XL plus (9800XL{sup +}) flatbed scanner. By using the PDD method, each one of the eight EBT2 films, four delivered by 290 monitor unit (MU) and four by 88 MU via 6-MV photon beams, was tightly sandwiched in a 30{sup 3}-cm{sup 3} water equivalent polystyrene phantom prior to irradiation. Before and after irradiation, all films were scanned using the Microtek 9800XL{sup +} scanner with five different modes of the multiple-sampling function, which could generate the image with the averaged result of multiple-sampling. The net optical densities (netOD) on the beam central axis of film were assigned to corresponding depth doses for calibration. For each sampling mode with either delivered MU, the depth-dose uncertainty of a single film from repeated scans and that of a single scan of the four films were analyzed. Finally, the calibration error and the combined calibration uncertainty between film determined depth-doses and delivered depth-doses were calculated and evaluated for each sampling mode. All standard deviations and the calibration error were demonstrated to be unrelated to the number of sampling lines. The calibration error of the 2-line and 16-line mode was within 3 cGy and better than that of the other modes. The combined uncertainty of the 2-line mode was the lowest, which was generally less than 6 cGy except for the delivered dose around 100 cGy. The evaluation described herein revealed that the EBT2 film calibrated with the 2-line mode has relatively lower error, scanning time and combined uncertianty. Therefore, it is recommended for routine EBT2 film calibration and verification of treatment plans.

Evaluation of Multiple-Sampling Function used with a Microtek flatbed scanner for Radiation Dosimetry Calibration of EBT2 Film

International Nuclear Information System (INIS)

Chang, Liyun; Ho, Sheng-Yow; Ding, Hueisch-Jy; Hwang, Ing-Ming; Chen, Pang-Yu; Lee, Tsair-Fwu

2016-01-01

The radiochromic EBT2 film is a widely used quality assurance device for radiation therapy. This study evaluated the film calibration performance of the multiple-sampling function, a function of the ScanWizard Pro scanning software provided by the manufacturer, when used with Microtek 9800XL plus (9800XL + ) flatbed scanner. By using the PDD method, each one of the eight EBT2 films, four delivered by 290 monitor unit (MU) and four by 88 MU via 6-MV photon beams, was tightly sandwiched in a 30 3 -cm 3 water equivalent polystyrene phantom prior to irradiation. Before and after irradiation, all films were scanned using the Microtek 9800XL + scanner with five different modes of the multiple-sampling function, which could generate the image with the averaged result of multiple-sampling. The net optical densities (netOD) on the beam central axis of film were assigned to corresponding depth doses for calibration. For each sampling mode with either delivered MU, the depth-dose uncertainty of a single film from repeated scans and that of a single scan of the four films were analyzed. Finally, the calibration error and the combined calibration uncertainty between film determined depth-doses and delivered depth-doses were calculated and evaluated for each sampling mode. All standard deviations and the calibration error were demonstrated to be unrelated to the number of sampling lines. The calibration error of the 2-line and 16-line mode was within 3 cGy and better than that of the other modes. The combined uncertainty of the 2-line mode was the lowest, which was generally less than 6 cGy except for the delivered dose around 100 cGy. The evaluation described herein revealed that the EBT2 film calibrated with the 2-line mode has relatively lower error, scanning time and combined uncertianty. Therefore, it is recommended for routine EBT2 film calibration and verification of treatment plans.

Gamma counter calibration system

International Nuclear Information System (INIS)

1977-01-01

A method and apparatus are described for the calibration of a gamma radiation measurement instrument to be used over any of a number of different absolute energy ranges. The method includes the steps of adjusting the overall signal gain associated with pulses which are derived from detected gamma rays, until the instrument is calibrated for a particular absolute energy range; then storing parameter settings corresponding to the adjusted overall signal gain, and repeating the process for other desired absolute energy ranges. The stored settings can be subsequently retrieved and reapplied so that test measurements can be made using a selected one of the absolute energy ranges. Means are provided for adjusting the overall signal gain and a specific technique is disclosed for making coarse, then fine adjustments to the signal gain, for rapid convergence of the required calibration settings. (C.F.)

Problems related to the use of annihilation radiation for precision energy calibration of Ge(Li) detectors

International Nuclear Information System (INIS)

Fransson, K.; Nilsson, A.; Raedt, J. de; Rensfelt, K.G.

1976-03-01

The energy of positron annihilation radiation emanating from several materials was measured, using recently established energies of the 198 Au and 192 Ir γ-rays for calibration. Corrections for the binding energy of positrons and electrons were applied. A peak fitting routine was used which took into account both the background step under the peak, and the possibility that only a part of the detector contains charge-carrier traps. The electron rest mass energy (corrected for binding energies) could be reproduced to within +- 10 eV, in some well-behaved metals even to within +- 5 eV. (Auth.)

Tritium β-radiation induction of chromosomal damage: a calibration curve for low dose, low dose rate exposures of human cells to tritiated water

International Nuclear Information System (INIS)

Morrison, D.P.; Gale, K.L.; Lucas, J.N.

1997-01-01

Radiation exposures from tritium contribute to the occupational radiation exposures associated with CANDU reactors. Tritiated water is of particular interest since it is readily taken up by human cells and its elimination from the body, and, consequently, the radiation exposure of the cells, is spread over a period of days. Occupational exposures to tritiated water result in what are effectively chronic β-radiation exposures. The doses and dose rates ordinarily used in the definition of cellular responses to radiation in vitro, for use in biological dosimetry (the assessment of radiation exposures based on the observed levels of changes in the cells of exposed individuals), are usually much higher than for most occupational exposures and involve radiations other than tritium β-rays. As a result, their use in assessing the effects from tritiated water exposures may not be appropriate. We describe here an in vitro calibration curve for chronic tritium β-radiation induction of reciprocal chromosomal translocations in humn peripheral blood lymphocytes (PBLs) for use in biodosimetry. (author)

Directional Degradation of Spectralon Diffuser Under Ionizing Radiation for Calibration of Space-Based Sensors

Science.gov (United States)

Georgiev, G. T.; Butler, J. J.; Kowalewski, M. G.; Ding, L.

2012-01-01

Assessment of the effect of Vacuum Ultra Violet (VUV) irradiation on the Bidirectional Reflectance Distribution Function (BRDF) of Spectralon is presented in this paper. The sample was a 99% white Spectralon calibration standard irradiated with VUV source positioned at 60o off the irradiation direction for a total of 20 hours. The BRDF before and after VUV irradiation was measured and compared at number of wavelengths in the UV, VIS and IR. Non-isotropic directional degradation of Spectralon diffuser under ionizing radiation was detected at different BRDF measurement geometries primarily at UV spectral range. The 8o directional/hemispherical reflectance of the same sample was also measured and compared from 200nm to 2500nm. Index Terms BRDF, Reflectance, Multiangular, Spectralon, Remote Sensing

PET/CT alignment calibration with a non-radioactive phantom and the intrinsic {sup 176}Lu radiation of PET detector

Energy Technology Data Exchange (ETDEWEB)

Wei, Qingyang [School of Automation and Electrical Engineering, University of Science & Technology Beijing, Beijing 100083 (China); Ma, Tianyu; Wang, Shi; Liu, Yaqiang [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Gu, Yu, E-mail: guyu@ustb.edu.cn [School of Automation and Electrical Engineering, University of Science & Technology Beijing, Beijing 100083 (China); Dai, Tiantian, E-mail: maxinedtt@163.com [Department of Radiation Oncology, China-Japan Friendship Hospital, Beijing 100029 (China)

2016-11-01

Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic {sup 176}Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic {sup 176}Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

Electro-optical equivalent calibration technology for high-energy laser energy meters

Energy Technology Data Exchange (ETDEWEB)

Wei, Ji Feng, E-mail: wjfcom2000@163.com [State Key Laboratory of Precision Measurement Technology and Instrument, Tsinghua University, Beijing 100084 (China); Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900 (China); Graduate School of China Academy of Engineering Physics, Beijing 100088 (China); Key Laboratory of Laser Science and Technology, China Academy of Engineering Physics, Mianyang 621900 (China); Chang, Yan; Zhang, Kai; Hu, Xiao Yang; Zhang, Wei [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900 (China); Key Laboratory of Laser Science and Technology, China Academy of Engineering Physics, Mianyang 621900 (China); Sun, Li Qun [State Key Laboratory of Precision Measurement Technology and Instrument, Tsinghua University, Beijing 100084 (China)

2016-04-15

Electro-optical equivalent calibration with high calibration power and high equivalence is particularly well-suited to the calibration of high-energy laser energy meters. A large amount of energy is reserved during this process, however, which continues to radiate after power-off. This study measured the radiation efficiency of a halogen tungsten lamp during power-on and after power-off in order to calculate the total energy irradiated by a lamp until the high-energy laser energy meter reaches thermal equilibrium. A calibration system was designed based on the measurement results, and the calibration equivalence of the system was analyzed in detail. Results show that measurement precision is significantly affected by the absorption factor of the absorption chamber and by heat loss in the energy meter. Calibration precision is successfully improved by enhancing the equivalent power and reducing power-on time. The electro-optical equivalent calibration system, measurement uncertainty of which was evaluated as 2.4% (k = 2), was used to calibrate a graphite-cone-absorption-cavity absolute energy meter, yielding a calibration coefficient of 1.009 and measurement uncertainty of 3.5% (k = 2). A water-absorption-type high-energy laser energy meter with measurement uncertainty of 4.8% (k = 2) was considered the reference standard, and compared to the energy meter calibrated in this study, yielded a correction factor of 0.995 (standard deviation of 1.4%).

On-line monitoring for calibration reduction

International Nuclear Information System (INIS)

Hoffmann, M.

2005-09-01

On-Line Monitoring evaluates instrument channel performance by assessing its consistency with other plant indications. Elimination or reduction of unnecessary field calibrations can reduce associated labour costs, reduce personnel radiation exposure, and reduce the potential for calibration errors. On-line calibration monitoring is an important technique to implement a state-based maintenance approach and reduce unnecessary field calibrations. In this report we will look at how the concept is currently applied in the industry and what the arising needs are as it becomes more commonplace. We will also look at the PEANO System, a tool developed by the Halden Project to perform signal validation and on-line calibration monitoring. Some issues will be identified that are being addressed in the further development of these tools to better serve the future needs of the industry in this area. An outline for how to improve these points and which aspects should be taken into account is described in detail. (Author)

Improvement of Accuracy in Environmental Dosimetry by TLD Cards Using Three-dimensional Calibration Method

Directory of Open Access Journals (Sweden)

HosseiniAliabadi S. J.

2015-06-01

Full Text Available Background: The angular dependency of response for TLD cards may cause deviation from its true value on the results of environmental dosimetry, since TLDs may be exposed to radiation at different angles of incidence from the surrounding area. Objective: A 3D setting of TLD cards has been calibrated isotropically in a standard radiation field to evaluate the improvement of the accuracy of measurement for environmental dosimetry. Method: Three personal TLD cards were rectangularly placed in a cylindrical holder, and calibrated using 1D and 3D calibration methods. Then, the dosimeter has been used simultaneously with a reference instrument in a real radiation field measuring the accumulated dose within a time interval. Result: The results show that the accuracy of measurement has been improved by 6.5% using 3D calibration factor in comparison with that of normal 1D calibration method. Conclusion: This system can be utilized in large scale environmental monitoring with a higher accuracy

New blackbody calibration source for low temperatures from -20 C to +350 C

Science.gov (United States)

Mester, Ulrich; Winter, Peter

2001-03-01

Calibration procedures for infrared thermometers and thermal imaging systems require radiation sources of precisely known radiation properties. In the physical absence of an ideal Planck's radiator, the German Committee VDI/VDE-GMA FA 2.51, 'Applied Radiation Thermometry', agreed upon desirable specifications and limiting parameters for a blackbody calibration source with a temperature range from -20 degree(s)C to +350 degree(s)C, a spectral range from 2 to 15 microns, an emissivity greater than 0.999 and a useful source aperture of 60 mm, among others. As a result of the subsequent design and development performed with the support of the laboratory '7.31 Thermometry' of the German national institute of natural and engineering sciences (PTB), the Mester ME20 Blackbody Calibration Source is presented. The ME20 meets or exceeds all of the specifications formulated by the VDI/VDE committee.

ECAL Energy Flow Calibration

CERN Multimedia

CERN. Geneva

2015-01-01

My talk will be covering my work as a whole over the course of the semester. The focus will be on using energy flow calibration in ECAL to check the precision of the corrections made by the light monitoring system used to account for transparency loss within ECAL crystals due to radiation damage over time.

Self-Calibration of CMB Polarimeters

Science.gov (United States)

Keating, Brian

2013-01-01

Precision measurements of the polarization of the cosmic microwave background (CMB) radiation, especially experiments seeking to detect the odd-parity "B-modes", have far-reaching implications for cosmology. To detect the B-modes generated during inflation the flux response and polarization angle of these experiments must be calibrated to exquisite precision. While suitable flux calibration sources abound, polarization angle calibrators are deficient in many respects. Man-made polarized sources are often not located in the antenna's far-field, have spectral properties that are radically different from the CMB's, are cumbersome to implement and may be inherently unstable over the (long) duration these searches require to detect the faint signature of the inflationary epoch. Astrophysical sources suffer from time, frequency and spatial variability, are not visible from all CMB observatories, and none are understood with sufficient accuracy to calibrate future CMB polarimeters seeking to probe inflationary energy scales of ~1000 TeV. CMB TB and EB modes, expected to identically vanish in the standard cosmological model, can be used to calibrate CMB polarimeters. By enforcing the observed EB and TB power spectra to be consistent with zero, CMB polarimeters can be calibrated to levels not possible with man-made or astrophysical sources. All of this can be accomplished without any loss of observing time using a calibration source which is spectrally identical to the CMB B-modes. The calibration procedure outlined here can be used for any CMB polarimeter.

Recent developments in the specification and achievement of realistic neutron calibration fields

International Nuclear Information System (INIS)

Chartier, J.L.; Kluges, H.; Wiegel, B.; Schraube, H.

1997-01-01

In order to calibrate more accurately the neutron dosemeters involved in radiation protection, the concept of 'Realistic Neutron Calibration Fields' is considered as an appropriate alternative solution, making necessary new irradiation facilities which generate well-characterised neutron fields with energy and angular distribution replicating more closely practical workplace conditions. Several experienced laboratories have collaborated on a European project and proposed various approaches which are reviewed in this paper. A short description of the facilities currently in operation is given as well as a few characteristics of the available radiation fields. This description of the state of art is followed by a discussion of the problems to be solved for using such facilities for calibration purposes according to well-specified calibration procedures. (author)

Calibration of the neutron scintillation counter threshold

International Nuclear Information System (INIS)

Noga, V.I.; Ranyuk, Yu.N.; Telegin, Yu.N.

1978-01-01

A method for calibrating the threshold of a neutron counter in the form of a 10x10x40 cm plastic scintillator is described. The method is based on the evaluation of the Compton boundary of γ-spectrum from the discrimination curve of counter loading. The results of calibration using 60 Co and 24 Na γ-sources are given. In order to eValuate the Compton edge rapidly, linear extrapolation of the linear part of the discrimination curve towards its intersection with the X axis is recommended. Special measurements have shown that the calibration results do not practically depend on the distance between the cathode of a photomultiplier and the place where collimated γ-radiation of the calibration source reaches the scintillator

A photon pressure calibrator for the GEO 600 gravitational wave detector

International Nuclear Information System (INIS)

Mossavi, K.; Hewitson, M.; Hild, S.; Seifert, F.; Weiland, U.; Smith, J.R.; Lueck, H.; Grote, H.; Willke, B.; Danzmann, K.

2006-01-01

Interferometer mirror displacement induced by radiation pressure is used to demonstrate an alternative calibration method for the GEO 600 detector. The photon calibrator utilizes an amplitude modulated laser diode with up to 1.4 W output power at a wavelength of 1035 nm. The achieved accuracy of the strain amplitude calibration is dominated by the laser power calibration error, which is in the range of ±4% for the measurements presented in this Letter

Radiation measurement

International Nuclear Information System (INIS)

Go, Sung Jin; Kim, Seung Guk; No, Gyeong Seok; Park, Myeong Hwan; Ann, Bong Seon

1998-03-01

This book explains technical terms about radiation measurement, which are radiation, radiation quantity and unit such as prefix of international unit, unit for defence purposes of radiation, coefficient of radiation and interaction, kinds and principles of radiation detector, ionization chamber, G-M counter, G-M tube, proportional counter, scintillation detector, semiconductor radiation detector, thermoluminescence dosimeter, PLD, others detector, radiation monitor, neutron detector, calibration of radiation detector, statistics of counting value, activation analysis and electronics circuit of radiation detector.

Improvement of the calibration technique of clinical dosemeters

International Nuclear Information System (INIS)

Ehlin Caldas, L.V.

1988-08-01

Clinical dosemeters constituted of ionization chambers connected to electrometers are usually calibrated as whole systems in appropriate radiation fields against secondary standard dosemeters in calibration laboratories. This work reports on a technique of component calibration procedures separately for chambers and electrometers applied in the calibration laboratory of IPEN-CNEN, Brazil. For electrometer calibration, redundancy was established by using a standard capacitor of 1000pF (General Radio, USA) and a standard current source based on air ionization with Sr 90 (PTW, Germany). The results from both methods applied to several electrometers of clinical dosemeters agreed within 0.4%. The calibration factors for the respective chambers were determined by intercomparing their response to the response of a certified calibrated chamber in a Co 60 calibration beam using a Keithley electrometer type 617. Overall calibration factors compared with the product of the respective component calibration factors for the tested dosemeters showed an agreement better than 0.7%. This deviation has to be considered with regard to an uncertainty of 2.5% in routine calibration of clinical dosemeters. Calibration by components permits to calibrate ionization chambers one at a time for those hospitals who have several ionization chambers but only one electrometer (small hospitals, hospitals in developing countries). 6 refs, 2 figs, 2 tabs

Radiation survey meters used for environmental monitoring

International Nuclear Information System (INIS)

Bjerke, H.; Sigurdsson, T.; Meier Pedersen, K.; Grindborg, J.-E.; Persson, L.; Siiskonen, T.; Hakanen, A.; Kosunen, A.

2012-01-01

The Nordic dosimetry group set up the GammaRate project to investigate how its expertise could be used to assure appropriate usage of survey meters in environmental monitoring. Considerable expertise in calibrating radiation instruments exists in the Nordic radiation protection authorities. The Swedish, Finnish, Danish and Norwegian authorities operate Secondary Standard Dosimetry Laboratories (SSDLs) that provide users with calibration traceable to internationally recognised primary standards. These authorities together with the Icelandic authorities have formally cooperated since 2002 in the field of radiation dosimetry. Dosimetry is the base for assesment of risk from ionising radiation and calibration of instruments is an imported part in dosimetry. The Nordic dosimetry group has been focused on cancer therapy. This work extends the cooperation to the dosimetry of radiation protection and environmental monitoring. This report contains the formal, theoretical and practical background for survey meter measurements. Nordic standards dosimetry laboratories have the capability to provide traceable calibration of instruments in various types of radiation. To verify and explore this further in radiation protection applications a set of survey instruments were sent between the five Nordic countries and each of the authority asked to provide a calibration coefficient for all instruments. The measurement results were within the stated uncertainties, except for some results from NRPA for the ionchamber based instrument. The comparison was shown to be a valuable tool to harmonize the calibration of radiation protection instruments in the Nordic countries. Dosimetry plays an important role in the emergency situations, and it is clear that better traceability and harmonised common guidelines will improve the emergency preparedness and health. (Author)

Radiation survey meters used for environmental monitoring

Energy Technology Data Exchange (ETDEWEB)

Bjerke, H. (ed.) (Norwegian Radiation Protection Authority, NRPA (Norway)); Sigurdsson, T. (Icelandic Radiation Safety Authority, Geislavarnir Rikisins, GR (IS)); Meier Pedersen, K. (National Board of Health, Statens Institut for Straalebeskyttelse (SIS) (Denmark)); Grindborg, J.-E.; Persson, L. (Swedish Radiation Safety Authority, Straalsaekerhetsmyndigheten (SSM) (Sweden)); Siiskonen, T.; Hakanen, A.; Kosunen, A. (Radiation and Nuclear Safety Authority, Saeteilyturvakeskus (STUK) (Finland))

2012-01-15

The Nordic dosimetry group set up the GammaRate project to investigate how its expertise could be used to assure appropriate usage of survey meters in environmental monitoring. Considerable expertise in calibrating radiation instruments exists in the Nordic radiation protection authorities. The Swedish, Finnish, Danish and Norwegian authorities operate Secondary Standard Dosimetry Laboratories (SSDLs) that provide users with calibration traceable to internationally recognised primary standards. These authorities together with the Icelandic authorities have formally cooperated since 2002 in the field of radiation dosimetry. Dosimetry is the base for assesment of risk from ionising radiation and calibration of instruments is an imported part in dosimetry. The Nordic dosimetry group has been focused on cancer therapy. This work extends the cooperation to the dosimetry of radiation protection and environmental monitoring. This report contains the formal, theoretical and practical background for survey meter measurements. Nordic standards dosimetry laboratories have the capability to provide traceable calibration of instruments in various types of radiation. To verify and explore this further in radiation protection applications a set of survey instruments were sent between the five Nordic countries and each of the authority asked to provide a calibration coefficient for all instruments. The measurement results were within the stated uncertainties, except for some results from NRPA for the ionchamber based instrument. The comparison was shown to be a valuable tool to harmonize the calibration of radiation protection instruments in the Nordic countries. Dosimetry plays an important role in the emergency situations, and it is clear that better traceability and harmonised common guidelines will improve the emergency preparedness and health. (Author)

Calibration of ionization chambers and determination of the absorbed doses

International Nuclear Information System (INIS)

RANDRIANTSEHENO, H.F

1996-01-01

In order to further improve the accuracy of dosimetric measurements in radiation therapy, the IAEA and WHO supported the establishment of Secondary Standard Dosimetry Laboratory (SSDLs). These SSDLs bridge the gap between the primary measurement standards and the user of ionizing radiation by providing the latter with calibrations against the SSDLs' secondary standards and by giving technical advice and assistance. However, a properly calibrated dosimeter is just necessary first condition for the determination of the dose. It has been demonstrated that the success or failure of radiation treatment depends on the absorbed dose delivered to the tumour and that this should not vary by more than a few per cent from described values. [fr

Advisory Committee for the calibration standards of ionizing radiation measurement. Section 1.- X and γ radiations, electrons

International Nuclear Information System (INIS)

1980-01-01

Section I (Rayons X et γ, electrons) of the Comite Consultatif pour les Etalons de Mesure des Rayonnements Ionisants held its fifth meeting in May 1979. The members of the Section presented the work in progress in their respective laboratories; then they studied two documents describing the exposure measurements at BIPM and the conditions in which the comparisons are made. They also reviewed the exposure and absorbed dose comparisons performed at BIPM and elsewhere since 1977. New conditions of measurement were defined for the comparison of calorimeters in the BIPM 60 Co beam. Three working groups were set up to investigate the following problems: conversion from absorbed dose in graphite to absorbed dose in water, conversion from exposure to absorbed dose in water, and organization of an international comparison of Fricke chemical dosimeter systems. The growing importance of the radiation processing industry was stressed. Finally, the recent research work carried out at BIPM was presented and plans for the coming years were discussed. A recommendation was made concerning the study of calibrations in terms of absorbed dose in water [fr

Calibration and verification of surface contamination meters --- Procedures and techniques

International Nuclear Information System (INIS)

Schuler, C; Butterweck, G.; Wernli, C.; Bochud, F.; Valley, J.-F.

2007-03-01

A standardised measurement procedure for surface contamination meters (SCM) is presented. The procedure aims at rendering surface contamination measurements to be simply and safely interpretable. Essential for the approach is the introduction and common use of the radionuclide specific quantity 'guideline value' specified in the Swiss Radiation Protection Ordinance as unit for the measurement of surface activity. The according radionuclide specific 'guideline value count rate' can be summarized as verification reference value for a group of radionuclides ('basis guideline value count rate'). The concept can be generalized for SCM of the same type or for SCM of different types using he same principle of detection. A SCM multi source calibration technique is applied for the determination of the instrument efficiency. Four different electron radiation energy regions, four different photon radiation energy regions and an alpha radiation energy region are represented by a set of calibration sources built according to ISO standard 8769-2. A guideline value count rate representing the activity per unit area of a surface contamination of one guideline value can be calculated for any radionuclide using instrument efficiency, radionuclide decay data, contamination source efficiency, guideline value averaging area (100 cm 2 ), and radionuclide specific guideline value. n this way, instrument responses for the evaluation of surface contaminations are obtained for radionuclides without available calibration sources as well as for short-Iived radionuclides, for which the continuous replacement of certified calibration sources can lead to unreasonable costs. SCM verification is based on surface emission rates of reference sources with an active area of 100 cm 2 . The verification for a given list of radionuclides is based on the radionuclide specific quantity guideline value count rate. Guideline value count rates for groups of radionuclides can be represented within the maximum

Calibration and performance testing of electronic personal dosimeters (EPD)

International Nuclear Information System (INIS)

Banaga, H.A.

2008-04-01

In modern radiation protection practices, active personal dosimeters are becoming absolutely necessary operational tools for satisfying the ALARA principle. The aim of this work was to carry out calibration and performance testing of ten electronic personal dosimeters (EPD) used for the individual monitoring. The EPDs were calibrated in terms of operation radiation protection quantity, personal dose equivalent, Hp (10). Calibrations were carried out at three of x-ray beam qualities described in ISO 4037 namely 60, 100 and 150 kV in addition to Cs-137 gamma ray quality. The calibrations were performed using polymethylmethacrylate (PMMA) phantom with dimensions 20*20*15 cm 3 . Conversion coefficient Hp (10)/K air for the phantom was also calculated. The response and linearity of the dosimeter at the specified energies were also tested. The EPDs tested showed that the calibration coefficient ranged from 0.60 to 1.31 and an equivalent response for the specified energies that ranged from 0.76 to 1.67. The study demonstrated the possibility of using non standard phantom for calibrating dosimeters used for individual monitoring. The dosimeters under study showed a good response in all energies except the response in quality 100 kV. The linearity of the dosimeters was within ±15%, with the exception of the quality 100 kV where this limit was exceeded.(Author)

A comparison of Australian and Canadian calibration coefficients for air kerma and absorbed dose to water for 60Co gamma radiation.

Science.gov (United States)

Shortt, K R; Huntley, R B; Kotler, L H; Boas, J F; Webb, D V

2006-06-01

Australian and Canadian calibration coefficients for air kerma and absorbed dose to water for 60Co gamma radiation have been compared using transfer standard ionization chambers of types NE 2561 and NE 2611A. Whilst the primary standards of air kerma are similar, both being thick-walled graphite cavity chambers but employing different methods to evaluate the Awall correction, the primary standards of absorbed dose to water are quite different. The Australian standard is based on measurements made with a graphite calorimeter, whereas the Canadian standard uses a sealed water calorimeter. The comparison result, expressed as a ratio of calibration coefficients R=N(ARPANSA)/N(NRC), is 1.0006 with a combined standard uncertainty of 0.35% for the air kerma standards and 1.0052 with a combined standard uncertainty of 0.47% for the absorbed dose to water standards. This demonstrates the agreement of the Australian and Canadian radiation dosimetry standards. The results are also consistent with independent comparisons of each laboratory with the BIPM reference standards. A 'trilateral' analysis confirms the present determination of the relationship between the standards, within the 0.09% random component of the combined standard uncertainty for the three comparisons.

Optical model and calibration of a sun tracker

International Nuclear Information System (INIS)

Volkov, Sergei N.; Samokhvalov, Ignatii V.; Cheong, Hai Du; Kim, Dukhyeon

2016-01-01

Sun trackers are widely used to investigate scattering and absorption of solar radiation in the Earth's atmosphere. We present a method for optimization of the optical altazimuth sun tracker model with output radiation direction aligned with the axis of a stationary spectrometer. The method solves the problem of stability loss in tracker pointing at the Sun near the zenith. An optimal method for tracker calibration at the measurement site is proposed in the present work. A method of moving calibration is suggested for mobile applications in the presence of large temperature differences and errors in the alignment of the optical system of the tracker. - Highlights: • We present an optimal optical sun tracker model for atmospheric spectroscopy. • The problem of loss of stability of tracker pointing at the Sun has been solved. • We propose an optimal method for tracker calibration at a measurement site. • Test results demonstrate the efficiency of the proposed optimization methods.

Simulation of a room for neutron instrument calibration at LCR/UERJ

International Nuclear Information System (INIS)

Medeiros, M.P.C.; Estrada, J.J.S.; Gomes, R.G.; Santos, R.F.G.; Leite, S.P.; Alves, C.F.E.; Rebello, W.F.; Almeida, C.E. de

2013-01-01

In this work the MCNPX code was used to design a calibrating room for neutron detectors to be implemented in the Laboratorio de Ciencias Radiologicas of UERJ. The calibration room containing a neutron irradiator with a 241 Am-Be source, a linear positioning system, radiation detectors and a shadow cone was modeled. The ambient dose equivalent rate, ııı ∗ ı10ı, in adjacent to the calibration room areas, as well as neutron scattering caused by the room itself were calculated. Using an occupancy factor of 1/16 for all adjacent areas, 3.8 cm of 5% borated polyethylene or 5.5 cm of concrete for shielding is enough to satisfy radiation safety requirements. (author)

Calibration of dose meters used in radiotherapy

International Nuclear Information System (INIS)

1979-01-01

This manual is a practical guide, not a comprehensive textbook, to the instrumentation and procedures necessary to calibrate a radiation dose meter used in clinical practice against a secondary standard dose meter

Development of a quality assurance program for ionizing radiation secondary calibration laboratories

Energy Technology Data Exchange (ETDEWEB)

Heaton, H.T. II; Taylor, A.R. Jr. [Center for Devices and Radiological Health, Rockville, MD (United States)

1993-12-31

For calibration laboratories, routine calibrations of instruments meeting stated accuracy goals are important. One method of achieving the accuracy goals is to establish and follow a quality assurance program designed to monitor all aspects of the calibration program and to provide the appropriate feedback mechanism if adjustments are needed. In the United States there are a number of organizations with laboratory accreditation programs. All existing accreditation programs require that the laboratory implement a quality assurance program with essentially the same elements in all of these programs. Collectively, these elements have been designated as a Measurement Quality Assurance (MQA) program. This paper will briefly discuss the interrelationship of the elements of an MQA program. Using the Center for Devices and Radiological Health (CDRH) X-ray Calibration Laboratory (XCL) as an example, it will focus on setting up a quality control program for the equipment in a Secondary Calibration Laboratory.

Development of a quality assurance program for ionizing radiation secondary calibration laboratories

International Nuclear Information System (INIS)

Heaton, H.T. II; Taylor, A.R. Jr.

1993-01-01

For calibration laboratories, routine calibrations of instruments meeting stated accuracy goals are important. One method of achieving the accuracy goals is to establish and follow a quality assurance program designed to monitor all aspects of the calibration program and to provide the appropriate feedback mechanism if adjustments are needed. In the United States there are a number of organizations with laboratory accreditation programs. All existing accreditation programs require that the laboratory implement a quality assurance program with essentially the same elements in all of these programs. Collectively, these elements have been designated as a Measurement Quality Assurance (MQA) program. This paper will briefly discuss the interrelationship of the elements of an MQA program. Using the Center for Devices and Radiological Health (CDRH) X-ray Calibration Laboratory (XCL) as an example, it will focus on setting up a quality control program for the equipment in a Secondary Calibration Laboratory

Parameterization models for solar radiation and solar technology applications

Energy Technology Data Exchange (ETDEWEB)

Khalil, Samy A. [National Research Institute of Astronomy and Geophysics, Solar and Space Department, Marsed Street, Helwan, 11421 Cairo (Egypt)

2008-08-15

Solar radiation is very important for the evaluation and wide use of solar renewable energy systems. The development of calibration procedures for broadband solar radiation photometric instrumentation and the improvement of broadband solar radiation measurement accuracy have been done. An improved diffuse sky reference and photometric calibration and characterization software for outdoor pyranometer calibrations are outlined. Parameterizations for direct beam, total hemispherical and diffuse sky radiation and solar radiation technology are briefly reviewed. The uncertainties for various broadband solar radiations of solar energy and atmospheric effects are discussed. The varying responsivities of solar radiation with meteorological, statistical and climatological parameters and possibility atmospheric conditions was examined. (author)

Parameterization models for solar radiation and solar technology applications

International Nuclear Information System (INIS)

Khalil, Samy A.

2008-01-01

Solar radiation is very important for the evaluation and wide use of solar renewable energy systems. The development of calibration procedures for broadband solar radiation photometric instrumentation and the improvement of broadband solar radiation measurement accuracy have been done. An improved diffuse sky reference and photometric calibration and characterization software for outdoor pyranometer calibrations are outlined. Parameterizations for direct beam, total hemispherical and diffuse sky radiation and solar radiation technology are briefly reviewed. The uncertainties for various broadband solar radiations of solar energy and atmospheric effects are discussed. The varying responsivities of solar radiation with meteorological, statistical and climatological parameters and possibility atmospheric conditions was examined

Laser's calibration of an AOTF-based spectral colorimeter

Science.gov (United States)

Emelianov, Sergey P.; Khrustalev, Vladimir N.; Kochin, Leonid B.; Polosin, Lev L.

2003-06-01

The paper is devoted to expedients of AOTF spectral colorimeters calibration. The spectrometer method of color values measuring with reference to spectral colorimeters on AOTF surveyed. The theoretical exposition of spectrometer data processing expedients is offered. The justified source of radiation choice, suitable for calibration of spectral colorimeters is carried out. The experimental results for different acousto-optical mediums and modes of interaction are submitted.

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

Energy Technology Data Exchange (ETDEWEB)

Kulisek, J.A., E-mail: Jonathan.Kulisek@pnnl.gov; Schweppe, J.E.; Stave, S.C.; Bernacki, B.E.; Jordan, D.V.; Stewart, T.N.; Seifert, C.E.; Kernan, W.J.

2015-06-01

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

Experimental comparison among the laboratories accredited within the framework of the European Co-operation for Accreditation on the calibration of a radiation protection dosimeters in the terms of the quantity air Kerma

International Nuclear Information System (INIS)

Bovi, M.; Toni, M.P.; Tricomi, G.

2002-01-01

The European co-operation for Accreditation (EA) formalises the collaboration of the Accreditation Bodies of the Member States of the European Union and the European Free Trade Association covering all conformity assessment activities. This collaboration is based on a Memorandum of Understanding dated the 27 November 1997 and aims at developing and maintain Multilateral Agreements (MLAs) within EA and with non-members accreditation bodies. MLAs Signatories guarantee uniformity of accreditation by continuous and rigorous evaluation. Based on mutual confidence, the MLAs recognise the equivalence of the accreditation systems administered by EA Members and of certificates and reports issued by bodies accredited under these systems. A basic element of the program to establish and maintain mutual confidence among calibration services is the participation of the accredited laboratories in experimental interlaboratory comparisons (ILC) organised by EA members or other international organisations. The aim of these ILC is to verify the technical equivalence of calibration services within the EA. The ILC which it is dealt with in the present work was recently carried out over a period of two years, ending in May 2002. It interested the laboratories accredited in the ionising radiation field for calibration of dosimeters at radiation protection levels in terms of the quantity air kerma (K air ) due to 6 0C o and 1 37C s gamma radiation. The ILC was planned by the EA expert group on Ionising radiation and radioactivity and approved by the EA General Assembly in December 1999 with the title Calibration of a Radiation Protection Dosimeter under the code IR3. The need of this comparison also resulted from an inquiry carried out in 1998 by the expert group among the different Accreditation Bodies members of EA and associated to EA. The organization of the ILC was carried out according to the EA rules by the Italian Accreditation Body in the ionising radiation field, the SIT

Neutron Spectrometry for Radiation Protection Purposes

International Nuclear Information System (INIS)

McDonald, Joseph C.

2001-01-01

Determination of the dose equivalent is required for radiation protection purposes, however such a determination is quite difficult for neutron radiation. In order to perform accurate dosimetric determinations, it is necessary to acquire information about the neutron fluence spectrum in the workplace as well as the reference radiations used to calibrate dosimetric instruments. This information can then be used to select the appropriate dosimetric instrument, the optimum calibration condition or to establish correction factors that account for the differences in calibration and workplace conditions. For quite some time, neutron spectrometry has been used for these purposes. A brief review of the applications of spectrometers in radiation protection and some recommendations for further development are given here

Neutron spectrometry for radiation protection purposes

CERN Document Server

McDonald, J C; Alberts, W G

2002-01-01

Determination of the dose equivalent is required for radiation protection purposes, however such a determination is quite difficult for neutron radiation. In order to perform accurate dosimetric determinations, it is advantageous to acquire information about the neutron fluence spectrum in the workplace as well as the reference radiations used to calibrate dosimetric instruments. This information can then be used to select the appropriate dosimetric instrument, the optimum calibration condition or to establish correction factors that account for the differences in calibration and workplace conditions. For quite some time, neutron spectrometry has been used for these purposes. A brief review of the applications of spectrometers in radiation protection and some recommendations for further development are given here.

Calibración de un sistema electrónico para la caracterización óptica de diodos emisores de luz

OpenAIRE

Vara Lubiano, Mónica

2017-01-01

El objetivo de este trabajo es la calibración de un sistema electrónico capaz de automatizar la obtención de espectros de emisión de fuentes de luz. Se trata de obtener una medida de la irradiancia de la fuente, es decir, potencia suministrada por la misma por unidad de superficie y para cada longitud de onda. En primer lugar se calibró la medida de la longitud de onda. Éste proceso consistió en la comparaci ón directa del espectro obtenido por el sistema con el valor conocido ...

Calibration of a tertiary standard in N-ISO qualities for radioprotection and personal dosimetry

International Nuclear Information System (INIS)

Rojas, Enrique; Seminario, Lizet

2013-01-01

Dosimetric calibration of radiation monitors and personal dosimeters in different radiological quantities are performed in order to obtain accurate measurements, for this reason the SSDL calculates the dosimetry calibration factor and its associated uncertainty, for each range of use. The calibration factor is performed using the known radiation field method and its uncertainty is calculated according to the ISO recommendations. The SSDL calculates the expanded uncertainty (U c ) with a coverage factor that provides a level of not less than 95 % of confidence. (authors).

Report on the state of heavy water system during distillation - Annex 8; Prilog 8 - Izvestaj o stanju teskovodnog sistema u toku destilacije

Energy Technology Data Exchange (ETDEWEB)

Zecevic, V [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

1963-12-15

Measurements of radiation level were done in 7 points of the heavy water system and distillation system. Measuring results shown in this report show that the radiation intensity was highest on the heat exchangers and lowest on the incoming pipe at the heavy water distillation system. [Serbo-Croat] Merenja intenziteta zracenja vrsena su u 7 tacaka teskovodnog sistema i sistema destilacije. Rezultati merenja prikazani u ovom izvestaju pokazuju da je intenzitet zracenja najveci na toploizmenjivacima, a najmanji na dovodnoj cevi teske vode na destilaciji.

Tour of the Standards and Calibrations Laboratory

International Nuclear Information System (INIS)

Elliott, J.H.

1978-01-01

This tour of Lawrence Livermore Laboratory's Standards and Calibrations Laboratory is intended as a guide to the capabilities of and services offered by this unique laboratory. Described are the Laboratory's ability to provide radiation fields and measurements for dosimeters, survey instruments, spectrometers, and sources and its available equipment and facilities. The tour also includes a survey of some Health Physics and interdepartmental programs supported by the Standards and Calibrations Laboratory and a listing of applicable publications

A simultaneous electron energy and dosimeter calibration method for an electron beam irradiator

International Nuclear Information System (INIS)

Tanaka, R.; Sunaga, H.; Kojima, T.

1991-01-01

In radiation processing using electron accelerators, the reproducibility of absorbed dose in the product depends not only on the variation of beam current and conveyor speed, but also on variations of other accelerator parameters. This requires routine monitoring of the beam current and the scan width, and also requires periodical calibration of routine dosimeters usually in the shape of film, electron energy, and other radiation field parameters. The electron energy calibration is important especially for food processing. The dose calibration method using partial absorption calorimeters provides only information about absorbed dose. Measurement of average electron current density provides basic information about the radiation field formed by the beam scanning and scattering at the beam window, though it does not allow direct dose calibration. The total absorption calorimeter with a thick absorber allows dose and dosimeter calibration, if the depth profile of relative dose in a reference absorber is given experimentally. It also allows accurate calibration of the average electron energy at the surface of the calorimeter core, if electron fluence received by the calorimeter is measured at the same time. This means that both electron energy and dosimeters can be simultaneously calibrated by irradiation of a combined system including the calorimeter, the detector of the electron current density meter, and a thick reference absorber for depth profile measurement of relative dose. We have developed a simple and multifunctional system using the combined calibration method for 5 MeV electron beams. The paper describes a simultaneous calibration method for electron energy and film dosimeters, and describes the electron current density meter, the total absorption calorimeter, and the characteristics of this method. (author). 13 refs, 7 figs, 3 tabs

A New Automated Instrument Calibration Facility at the Savannah River Site

International Nuclear Information System (INIS)

Polz, E.; Rushton, R.O.; Wilkie, W.H.; Hancock, R.C.

1998-01-01

The Health Physics Instrument Calibration Facility at the Savannah River Site in Aiken, SC was expressly designed and built to calibrate portable radiation survey instruments. The facility incorporates recent advances in automation technology, building layout and construction, and computer software to improve the calibration process. Nine new calibration systems automate instrument calibration and data collection. The building is laid out so that instruments are moved from one area to another in a logical, efficient manner. New software and hardware integrate all functions such as shipping/receiving, work flow, calibration, testing, and report generation. Benefits include a streamlined and integrated program, improved efficiency, reduced errors, and better accuracy

Pilot study to verify the calibration of electrometers

International Nuclear Information System (INIS)

Becker, P.; Meghzifene, A.

2002-01-01

Full text: The main detector used for standardization of the quantities used in measurements of ionizing radiation is the ionization chamber. The interaction of the radiation with this detector produces electrical charge, usually, in the range of pC to nC. The instrument used to measure such small charges (or currents) is the electrometer. As part of a good practice, the measured charge (current) must be traceable to a primary or secondary standard. Some calibration laboratories can only provide a system calibration coefficient, i.e. a calibration coefficient for the combination of electrometer plus ionization chamber (Gy/scale division). This practice is acceptable, but it can impose a limitation to the automation of their calibration procedures (using computerized application for the acquisition of current/charge). Not all models have the possibility of a connection to a computer and in the case of those that don't have this capability, automation is not possible without the development of a specific interface. In addition, end-users receive a calibration coefficient, which is only valid for the set ion chamber and electrometer. In case of a broken chamber, the end-user cannot connect another chamber to their electrometer without knowing its calibration coefficient. If the calibration laboratories had the capability of calibrating the chamber separately from the electrometer, for example, using an electrometer calibrated in terms of charge, all the chambers could be calibrated using this electrometer. The laboratory can also benefit from the automation of the measurements. This requires that the laboratory must be able to cross-calibrate the electrometers (associated to the chambers) also in terms of charge (Coulombs). Electrical charge is standardized by the use of a standard air capacitor and a standard voltage source (Q=CV) and the National Laboratory for Metrology of Ionizing Radiation (IRD) in Brazil has also adopted this procedure. Since the Brazilian

en tres sistemas agroforestales

Directory of Open Access Journals (Sweden)

Javier Monge Meza

2006-01-01

Full Text Available Se estudió el desarrollo inicial (30 meses del duraznillo (Prunus annularis en tres sistemas agroforestales: duraznillo-maíz (Zea mays, duraznillomenta (Satureja viminea y duraznillo-naranjilla (Solanum quitoense, en un sitio en la zona de vida Bosque muy húmedo Montano Bajo, en Costa Rica. Se utilizaron cuatro parcelas de cada sistema agroforestal, con una densidad de 722 árboles/ ha, y un sistema de siembra de árboles en forma de triángulo equilátero, entre los que se intercaló el componente agrícola respectivo de cada sistema agroforestal. La altura media alcanzada por los árboles de duraznillo fue de 226,2, 221,4 y 164,3 cm, para el sistema agroforestal duraznillo-maíz, duraznillo- menta y duraznillo-naranjilla, respectivamente. En cuanto a los volúmenes, éstos variaron entre 0,58 y 1,30 m3/ha. Hubo una diferencia significativa en altura media entre el sistema agroforestal duraznillo-maíz y duraznillo-menta con respecto al de duraznillo-naranjilla. No hubo diferencias con respecto al volumen entre los sistemas de producción

Dosimetry and Calibration Section

International Nuclear Information System (INIS)

Otto, T.

1999-01-01

The Dosimetry and Calibration Section fulfils two tasks within CERN's Radiation Protection Group: the Individual Dosimetry Service monitors more than 5000 persons potentially exposed to ionizing radiation on the CERN sites, and the Calibration Laboratory verifies throughout the year, at regular intervals, over 1000 instruments, monitors, and electronic dosimeters used by RP Group. The establishment of a Quality Assurance System for the Individual Dosimetry Service, a requirement of the new Swiss Ordinance for personal dosimetry, put a considerable workload on the section. Together with an external consultant it was decided to identify and then describe the different 'processes' of the routine work performed in the dosimetry service. The resulting Quality Manual was submitted to the Federal Office for Public Health in Bern in autumn. The CERN Individual Dosimetry Service will eventually be officially endorsed after a successful technical test in March 1999. On the technical side, the introduction of an automatic development machine for gamma films was very successful. It processes the dosimetric films without an operator being present, and its built-in regeneration mechanism keeps the concentration of the processing chemicals at a constant level

Procedures for the definitive calibration of radiotherapy equipment

International Nuclear Information System (INIS)

1993-01-01

Recommendations from the Institute of Physical Sciences in Medicine are given for the definition calibration of external beam radiotherapy treatment machines and radiation dose measuring equipment used in radiotherapy. (UK)

Calibration of dosimeters used in radiotherapy. A manual

International Nuclear Information System (INIS)

1994-01-01

The present manual is a revision of IAEA Technical Reports Series No.185, published in 1979. This manual is intended for use by the network of Secondary Standard Dosimetry Laboratories (SSDLs) which was set up by the IAEA and the World Health Organization (WHO). The objectives of the SSDL network are to: calibrate radiation dosimeters and ancillary instruments; serve as a link between primary standard laboratories and radiation users; and provide advice and assistance in all aspects of radiation metrology. The various calibration procedures are described, their relative advantages and disadvantages are discussed, and criteria are put forward to help an SSDL decide which procedure is the best to use in order to meet a particular requirement. The information in this manual should also be of value to other similar laboratories, usually associated with hospitals, which are not formally part of the IAEA/WHO network of SSDLs. 26 refs, 6 figs, 6 tabs

Setup and Calibration of SLAC's Peripheral Monitoring Stations

Energy Technology Data Exchange (ETDEWEB)

Cooper, C.

2004-09-03

The goals of this project were to troubleshoot, repair, calibrate, and establish documentation regarding SLAC's (Stanford Linear Accelerator Center's) PMS (Peripheral Monitoring Station) system. The PMS system consists of seven PMSs that continuously monitor skyshine (neutron and photon) radiation levels in SLAC's environment. Each PMS consists of a boron trifluoride (BF{sub 3}) neutron detector (model RS-P1-0802-104 or NW-G-20-12) and a Geiger Moeller (GM) gamma ray detector (model TGM N107 or LND 719) together with their respective electronics. Electronics for each detector are housed in Nuclear Instrument Modules (NIMs) and are plugged into a NIM bin in the station. All communication lines from the stations to the Main Control Center (MCC) were tested prior to troubleshooting. To test communication with MCC, a pulse generator (Systron Donner model 100C) was connected to each channel in the PMS and data at MCC was checked for consistency. If MCC displayed no data, the communication cables to MCC or the CAMAC (Computer Automated Measurement and Control) crates were in need of repair. If MCC did display data, then it was known that the communication lines were intact. All electronics from each station were brought into the lab for troubleshooting. Troubleshooting usually consisted of connecting an oscilloscope or scaler (Ortec model 871 or 775) at different points in the circuit of each detector to record simulated pulses produced by a pulse generator; the input and output pulses were compared to establish the location of any problems in the circuit. Once any problems were isolated, repairs were done accordingly. The detectors and electronics were then calibrated in the field using radioactive sources. Calibration is a process that determines the response of the detector. Detector response is defined as the ratio of the number of counts per minute interpreted by the detector to the amount of dose equivalent rate (in mrem per hour, either calculated

Project of an integrated calibration laboratory of instruments at IPEN

International Nuclear Information System (INIS)

Barros, Gustavo Adolfo San Jose

2009-01-01

The Calibration Laboratory of Instruments of Instituto de Pesquisas Energeticas e Nucleares offers calibration services of radiation detectors used in radioprotection, diagnostic radiology and radiotherapy, for IPEN and for external facilities (public and private). One part of its facilities is located in the main building, along with other laboratories and study rooms, and another part in an isolated building called Bunker. For the optimization, modernization and specially the safety, the laboratories in the main building shall be transferred to an isolated place. In this work, a project of an integrated laboratory for calibration of instruments was developed, and it will be an expansion of the current Calibration Laboratory of Instruments of IPEN. Therefore, a series of radiometric monitoring of the chosen localization of the future laboratory was realized, and all staff needs (dimensions and disposition of the study rooms and laboratories) were defined. In this project, the laboratories with X ray equipment, alpha and beta radiation sources were located at an isolated part of the building, and the wall shielding was determined, depending on the use of each laboratory. (author)

Study of radiation detectors response in standard X, gamma and beta radiation standard beams

International Nuclear Information System (INIS)

Nonato, Fernanda Beatrice Conceicao

2010-01-01

The response of 76 Geiger-Mueller detectors, 4 semiconductor detectors and 34 ionization chambers were studied. Many of them were calibrated with gamma radiation beams ( 37 Cs and 60 Co), and some of them were tested in beta radiation ( 90 Sr+ 9' 0Y e 204 Tl) and X radiation (N-60, N-80, N-100, N-150) beams. For all three types of radiation, the calibration factors of the instruments were obtained, and the energy and angular dependences were studied. For beta and gamma radiation, the angular dependence was studied for incident radiation angles of 0 deg and +- 45 deg. The curves of the response of the instruments were obtained over an angle interval of 0 deg to +- 90 deg, for gamma, beta and X radiations. The calibration factors obtained for beta radiation were compared to those obtained for gamma radiation. For gamma radiation, 24 of the 66 tested Geiger-Mueller detectors presented results for the energy dependence according to international recommendation of ISO 4037-2 and 56 were in accordance with the Brazilian ABNT 10011 recommendation. The ionization chambers and semiconductors were in accordance to national and international recommendations. All instruments showed angular dependence less than 40%. For beta radiation, the instruments showed unsatisfactory results for the energy dependence and angular dependence. For X radiation, the ionization chambers presented results for energy dependence according to the national recommendation, and the angular dependence was less than 40%. (author)

Method and circuit for stabilizing conversion gain of radiation detectors of a radiation detection system

International Nuclear Information System (INIS)

Stoub, E.W.

1986-01-01

A method is described for calibrating the gain of an array of radiation detectors of a radiation detection system comprising the steps of: (a) measuring in parallel for each radiation detector using a predetermined calibration point the energy map status, thereby obtaining an energy response vector whose elements correspond to the individual output of each radiation detector, each predetermined calibration point being a prescribed location corresponding to one of the radiation detectors; (b) multiplying that energy response vector with a predetermined deconvolution matrix, the deconvolution matrix being the inversion of a contribution matrix containing matrix elements C/sub IJ/, each such matrix element C/sub IJ/ of the contribution matrix representing the relative contribution level of a radiation detector j of the detection system for a point radiation source placed at a location i, thereby obtaining a gain vector product for the radiation detectors; (c) adjusting the gains of the radiation detectors with respect to the gain vector product such that a unity gain vector is essentially obtained; (d) measuring again the energy map status according to step (a); and (e) if the energy map status fails to essentially produce a unity gain vector repeat steps (a) to (d) until the energy map status substantially corresponds to unity

Performance and quality control of radionuclide calibrators in nuclear medicine

International Nuclear Information System (INIS)

Woods, M.J.; Baker, M.

2002-01-01

Full text: The use of ionising radiations in nuclear medicine has traditionally divided itself into two specific areas. The diagnostic usage has generally been dominated by the injection or ingestion of radionuclides. The therapeutic applications, on the other hand, have usually been accomplished by the application of ionising radiation, both from machines and radionuclide sources, whereby the radiation source is external to the patient. Over recent years, this divide has become increasingly blurred and the science between diagnosis and therapy has become significantly closer. This is particularly the situation in respect of the instruments used to determine the activity or dose delivered by the radiation source. In the ideal therapeutic situation, the radiation dose would be delivered solely to the malignant tissue. With external radiation therapy, this can never be achieved completely but this ideal can be approached more closely with targeted radiotherapy wherein radionuclides are introduced directly into the malignancy either as a solid, physical source or as a solution that, by its chemistry, concentrates into the area of interest. In order to achieve the optimum efficacy of treatment, there is an associated requirement to determine accurately the activity or dose rate of the radioactive source being used. It is here that the technology used in the diagnostic field can also be used to advantage for therapeutic applications. For diagnosis, the instrument of choice is the radionuclide calibrator and this equipment is increasingly finding parallel usage for the characterisation of therapeutic sources. Despite their appearances however, radionuclide calibrators are not 'black boxes' and need to be used with care, subjected to a robust level of quality control and operated by personnel who have a fundamental understanding of their operational characteristics. A measure of the level of performance of operational radionuclide calibrators and the competence of their

Radiochromic film calibration for the RQT9 quality beam

Science.gov (United States)

Costa, K. C.; Gomez, A. M. L.; Alonso, T. C.; Mourao, A. P.

2017-11-01

When ionizing radiation interacts with matter it generates energy deposition. Radiation dosimetry is important for medical applications of ionizing radiation due to the increasing demand for diagnostic radiology and radiotherapy. Different dosimetry methods are used and each one has its advantages and disadvantages. The film is a dose measurement method that records the energy deposition by the darkening of its emulsion. Radiochromic films have a little visible light sensitivity and respond better to ionizing radiation exposure. The aim of this study is to obtain the resulting calibration curve by the irradiation of radiochromic film strips, making it possible to relate the darkening of the film with the absorbed dose, in order to measure doses in experiments with X-ray beam of 120 kV, in computed tomography (CT). Film strips of GAFCHROMIC XR-QA2 were exposed according to RQT9 reference radiation, which defines an X-ray beam generated from a voltage of 120 kV. Strips were irradiated in "Laboratório de Calibração de Dosímetros do Centro de Desenvolvimento da Tecnologia Nuclear" (LCD / CDTN) at a dose range of 5-30 mGy, corresponding to the range values commonly used in CT scans. Digital images of the irradiated films were analyzed by using the ImageJ software. The darkening responses on film strips according to the doses were observed and they allowed obtaining the corresponding numeric values to the darkening for each specific dose value. From the numerical values of darkening, a calibration curve was obtained, which correlates the darkening of the film strip with dose values in mGy. The calibration curve equation is a simplified method for obtaining absorbed dose values using digital images of radiochromic films irradiated. With the calibration curve, radiochromic films may be applied on dosimetry in experiments on CT scans using X-ray beam of 120 kV, in order to improve CT acquisition image processes.

sistemas

Directory of Open Access Journals (Sweden)

Diego Alejandro Muñoz Gaviria

2006-01-01

Full Text Available El texto presentado a continuación, plantea en términos generales las principales posturas conceptuales del sociólogo alemán Niklas Luhmann sobre las ideas de Max Weber y su teoría de la acción social, y de Talcott Parsons y sus planteamientos en torno a la teoría de los sistemas sociales. Al final del escrito se hace especial énfasis en el rol protagónico que para Luhmann tienen las ciencias sociales y humanas en la autorreferencia del sistema social.

Activities of Radiation Standard Section

International Nuclear Information System (INIS)

Kannan, A.; Rao, P.S.; Sachadev, R.N.; Shaha, V.V.; Sharma, D.; Srivastava, P.K.

1992-01-01

A brief account of the various facilities and services provided by the Radiation Standards Section (RSS) of the Bhabha Atomic Research Centre, Bombay is given. RSS maintains the primary and secondary standards of various parameters of radiation measurements. It ensures accurate radiological measurements as per international requirements, through periodic international intercomparisons of national standards. It also provides calibration services to various users of radiation sources and instruments. The activities of RSS are described under the headings: (1) Radiological Metrology Standards, (2) Radionuclide Standards, Neutron Metrology, (4) Instruments Calibration, (5) Non-ionizing Radiations, and (6) Instrumentation. (author). figs., tabs

SSDL for radiation protection of Thailand

International Nuclear Information System (INIS)

Wanitsuksombut, W.

1995-01-01

In Thailand, the Atomic Energy for Peace Act was enacted by the King in 1961, and Office of Atomic Energy for Peace was established to serve as the secretariat of the Atomic Energy for Peace Commission of Thailand. The import and export of radioactive materials, and the owners and users of radioactive materials must be licensed by the OAEP. The program for establishing the SSDL to calibrate radiation protection instruments started in 1981, and was completed in 1990. The calibration of survey meters and direct reading personnel dosimeters has been provided since 1986. The average number of the devices calibrated by the SSDL per month is shown. The categories of radiation utilization in Thailand are nucleonic gauging and control, nondestructive testing, oil and coal logging, radiation technology and research. The capability of the SSDL and the calibrated radiation measuring instruments for respective categories of utilization are reported. The number of the instruments used for radiography was 217, followed by 171 for nucleonic gauging and control. With the increasing use of radioactive materials, the work of radiation safety must be improved. Together with the license authority, the SSDL must expand its activity to assure the safe handling of radiation sources. (K.I.)

Characteristic parameters analysis on diagnostic X-ray beams for dosemeter calibration

International Nuclear Information System (INIS)

Oliveira, Paulo Marcio Campos de

2008-01-01

Ionizing radiation metrology is the base to achieve reliable dose measurements in ali areas; it is also part of the framework that is established to assure radiation protection procedures in order to avoid or minimize the harmful biological effect that may be caused by ionizing radiation. A well done metrology means the use of reliable instruments that comply with standard performance requirements worldwide accepted. Those instruments are expected to be calibrated by Metrology Laboratories under well defined conditions. The International Electrotechnical Commission (IEC) in Standard 61267 established the reference radiations for medical diagnostic x-ray equipment that are recommended to be used for calibrating dosimetric systems for diagnostic dosimetry. In this work, X-ray beam qualities were established in a Calibration Laboratory and their characteristics were analyzed through the measurement of beam parameters like inherent tube filtration, beam uniformity and field size, energy spectra and peak voltage for additional filtration with 94.425 por cent and 99.999 por cent purity filters. Also, the first half-value layer and the homogeneity coefficient were measured for the three RQR 2, RQR 6 and RQR 10 IEC beam qualities and they were analyzed according to the IEC standard. Air-kerma measurements were carried out with an ionization chamber that had its reliability confirmed through repetition and reproducibility reading tests. In 50 sets of measurements the maximum standard deviation found of 10 successive readings was 0.19 %; the maximum shift of the reading mean value at a fixed geometry condition was 0.80 % with an overall standard deviation of 0.23 %. Results showed that the use of different purity filters did not cause a relevant influence on the beam energy spectra. An ionization chamber was also calibrated against a standard dosimeter in ali implemented reference radiations and the relevant sources of uncertainties were estimated. Calibration could be done

Sistema de seguridad en redes locales utilizando sistemas multiagentes distribuidos. Net-Mass

Directory of Open Access Journals (Sweden)

Daniel Horfan Álvarez

2005-01-01

Full Text Available La seguridad en las redes de datos es uno de los elementos neurálgicos dentro de una organización, ya que requiere de diferentes estrategias de protección para salvaguardar puntos vulnerables, y de la coordinación y distribución de esfuerzos para cercar todas las posibles formas de ataques informáticos. En este artículo se propone un sistema multiagente distribuido como herramienta de protección para redes con diferentes sistemas operativos y susceptibilidad de diversos ataques.El sistema propuesto está conformado por un grupo de agentes autónomos heterogéneos con características particulares en cuanto a sus estrategias de detección de intrusos y protección de los sistemas primordiales de la red, se tiene planeado que estos agentes basen sus decisiones en la aplicación de diferentes técnicas de inteligencia artificial como heurística de sistemas expertos, algoritmos evolutivos y redes neuronales.

Evaluation of the need for radiotherapy calibrations in the United States

International Nuclear Information System (INIS)

Lanzl, L.H.; Rozenfeld, M.; r.

1977-01-01

The custody, maintenance, and development of the United States national standards of measurement, together with the provision of calibration services related to these standards, has been assigned to the National Bureau of Standards (NBS) of the U. S. Department of Commerce. It may be that the present system of promulgation of radiation standards is no longer adequate for the United States. Ionizing radiation is being used increasingly for the treatment of cancer patients. At present, approximately 325,000 new cancer patients per year are given radiation treatment at over 1500 centers. With this growing use of ionizing radiations, an increased awareness of the importance of accurate and precise dosimetry has developed. To determine the adequacy of these dosimetric needs, the AAPM has initiated a national study which is being conducted by means of a mailed questionnaire, and by a limited number of site visits to individuals who are in charge of radiation therapy centers as well as to those who do the actual calibrations

Non-contact radiation thickness gauge

International Nuclear Information System (INIS)

Tsujii, T.; Okino, T.

1983-01-01

A noncontact thickness gauge system for measuring the thickness of a material comprising a source of radiation, a detector for detecting the amount of radiation transmitted through the material which is a function of the absorptance and thickness of the material, a memory for storing the output signals of the detector and curve-defining parameters for a plurality of quadratic calibration curves which correspond to respective thickness ranges, and a processor for processing the signals and curve defining parameters to determine the thickness of the material. Measurements are made after precalibration to obtain calibration curves and these are stored in the memory, providing signals representative of a nominal thickness and an alloy compensation coefficient for the material. The calibration curve corresponding to a particular thickness range is selected and the curve compensated for drift; the material is inserted into the radiation path and the detector output signal processed with the compensated calibration curve to determine the thickness of the material. (author)

Research on orbit prediction for solar-based calibration proper satellite

Science.gov (United States)

Chen, Xuan; Qi, Wenwen; Xu, Peng

2018-03-01

Utilizing the mathematical model of the orbit mechanics, the orbit prediction is to forecast the space target's orbit information of a certain time based on the orbit of the initial moment. The proper satellite radiometric calibration and calibration orbit prediction process are introduced briefly. On the basis of the research of the calibration space position design method and the radiative transfer model, an orbit prediction method for proper satellite radiometric calibration is proposed to select the appropriate calibration arc for the remote sensor and to predict the orbit information of the proper satellite and the remote sensor. By analyzing the orbit constraint of the proper satellite calibration, the GF-1solar synchronous orbit is chose as the proper satellite orbit in order to simulate the calibration visible durance for different satellites to be calibrated. The results of simulation and analysis provide the basis for the improvement of the radiometric calibration accuracy of the satellite remote sensor, which lays the foundation for the high precision and high frequency radiometric calibration.

Radiation camera exposure control

International Nuclear Information System (INIS)

Martone, R.J.; Yarsawich, M.; Wolczek, W.

1976-01-01

A system and method for governing the exposure of an image generated by a radiation camera to an image sensing camera is disclosed. The exposure is terminated in response to the accumulation of a predetermined quantity of radiation, defining a radiation density, occurring in a predetermined area. An index is produced which represents the value of that quantity of radiation whose accumulation causes the exposure termination. The value of the predetermined radiation quantity represented by the index is sensed so that the radiation camera image intensity can be calibrated to compensate for changes in exposure amounts due to desired variations in radiation density of the exposure, to maintain the detectability of the image by the image sensing camera notwithstanding such variations. Provision is also made for calibrating the image intensity in accordance with the sensitivity of the image sensing camera, and for locating the index for maintaining its detectability and causing the proper centering of the radiation camera image

Method and apparatus for calibrating spectrophotometers

NARCIS (Netherlands)

Schreutelkamp, F.H.

2003-01-01

The present invention relates to a method of calibrating spectrophotometers by placing one or more filters in the light path of the spectrophotometer and measuring the amount of radiation by means of a detector. The present invention furthermore relates to an apparatus to be used with such a method.

New in-flight calibration adjustment of the Nimbus 6 and 7 earth radiation budget wide field of view radiometers

Science.gov (United States)

Kyle, H. L.; House, F. B.; Ardanuy, P. E.; Jacobowitz, H.; Maschhoff, R. H.; Hickey, J. R.

1984-01-01

In-flight calibration adjustments are developed to process data obtained from the wide-field-of-view channels of Nimbus-6 and Nimbus-7 after the failure of the Nimbus-7 longwave scanner on June 22, 1980. The sensor characteristics are investigated; the satellite environment is examined in detail; and algorithms are constructed to correct for long-term sensor-response changes, on/off-cycle thermal transients, and filter-dome absorption of longwave radiation. Data and results are presented in graphs and tables, including comparisons of the old and new algorithms.

System calibration for air control of radioactive gases [contamination control]; Kalibracija sistema za kontrolu vazduha na radioaktivne gasove

Energy Technology Data Exchange (ETDEWEB)

Zecevic, V; Milosevic, M [Institute of Nuclear Sciences Boris Kidric, Reaktor RA, Vinca, Beograd (Serbia and Montenegro)

1963-02-15

Testing of the system for air contamination control at the RA reactor was done and calibrated by Ar{sup 41}. This report contains the report on testing and calibration. This activity was necessary in order to achieve its performance with existing dosimetry system in the RA reactor building.

Conception of the Instrument Calibration Laboratory of Ionizing Radiation Measurement (LACIMRI) of CTMSP - Sao Paulo, SP; Concepcao do Laboratorio de Calibracao de Instrumentos de Medicao de Radiacao Ionizante (LACIMRI) do CTMSP, Sao Paulo, SP

Energy Technology Data Exchange (ETDEWEB)

Silva, Raimundo Dias da; Kibrit, Eduardo, E-mail: raimundo@ctmsp.mar.mil.b, E-mail: kibrit@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil)

2009-07-01

The present work describes the phases of implantation of calibration laboratory of ionizing radiation measurement instruments at the CTMSP, Sao Paulo, in a priory approved by CNEN, Brazil. That laboratory will allow and enhance the present metrological capacity for the attendance to the growing demand for calibration services of the instruments

Calibration of germanium detectors

International Nuclear Information System (INIS)

Bjurman, B.; Erlandsson, B.

1985-01-01

This paper describes problems concerning the calibration of germanium detectors for the measurement of gamma-radiation from environmental samples. It also contains a brief description of some ways of reducing the uncertainties concerning the activity determination. These uncertainties have many sources, such as counting statistics, full energy peak efficiency determination, density correction and radionuclide specific-coincidence effects, when environmental samples are investigated at close source-to-detector distances

CP-50 calibration facility radiological safety assessment document

International Nuclear Information System (INIS)

Chilton, M.W.; Hill, R.L.; Eubank, B.F.

1980-03-01

The CP-50 Calibration Facility Radiological Safety Assessment document, prepared at the request of the Nevada Operations Office of the US Department of Energy to satisfy provisions of ERDA Manual Chapter 0531, presents design features, systems controls, and procedures used in the operation of the calibration facility. Site and facility characteristics and routine and non-routine operations, including hypothetical incidents or accidents are discussed and design factors, source control systems, and radiation monitoring considerations are described

Automatic calibration of spectrometer's tracts of installation for detecting of explosive materials

International Nuclear Information System (INIS)

Lajkin, A.I.; Mozhaev, A.N.; Kozlovskij, S.A.

2005-01-01

Calibration of the facility, representing the spectrometer and intended for the explosive substances detection on various objects is considered. The above work is based on the method of the neutron-radiation analysis. Brief description of the operational prototype, the basic characteristics, the capturing radiation background spectrum with a sample of the nitrogen-containing substance and the example of the calibration straight line are presented. The method of control sums and advantages of its application at the facilities for the explosive substances detection are considered [ru

Air Kerma above environmental radiometric calibration facility for field equipment

International Nuclear Information System (INIS)

Conti, C.C.; Sachett, I.A.; Bertelli, L.; Lopes, R.T.

2000-01-01

The use of gamma ray spectrometers broadened the aims of gamma ray surveys, stead of measuring only the gross radiation, as was done with the GM tubes, it is now possible to be used for uranium exploration, geological mapping as an aid to the exploration of non radioactive ores like gold and tin, radiation background measurements to identify hot spots for radiation hazard evaluation and environmental monitoring of fallout from radiological and nuclear accidents. It became necessary to carefully and precisely calibrate the field equipment to be used to get all the information from such uses. There is an environmental radiometric calibration facility for field equipment, consisting of eight radioactive concrete sources, at the Institute of Radioprotection and Dosimetry - IRD (CNEN/Brazil). These sources are cylindrical with 3 m diameter, 0.5 m thick and weigh about 7.5 tons each. The amount and type of the radioactive material, 238 U and 232 Th and 40 K ores in secular radioactive equilibrium, added to the concrete to simulate rock outcrops, varies in order to obtain different gamma fields, varying in both energy and intensity. These different radiation fields were measured with a HPGe portable detector, specifically calibrated for spectrum stripping, and the air kerma energy distribution was determined for each concrete source and compared with the total air kerma calculated from the nuclide concentration and by others radiometric methods. (author)

MAGNETIC GRADIOMETRY: Instrumentation, Calibration and Applications

DEFF Research Database (Denmark)

Merayo, Jose Maria Garcia

is to be used in the forthcoming satellites CHAMP and SAC-C. Linearity, thermal, radiation, dynamic and calibration tests are carried out to qualify the magnetometer in order to ensure state-of-the-art performance with subnanotesla precision. The overall calibration of the gradiometer yields an omnidirectional...... absolute accuracy of 93pT/m.The scalar calibration of a vector magnetometer is explained thoroughly. The novel method is simple and it represents the most robust and unique way to estimate the characterizing 9 parameters of a vector magnetometer. Its power relies on the linearization of the parametrization...... and offers the possibility of separating the geomagnetic field sources.By using tensor algebra the spherical harmonic expansion of the magnetic field in a curl free region and its associated gradient tensor are derived. This differential tensor quantity is then expressed by spherical coordinates...

SISTEMAS DE SECADO DEL ALMIDÓN DE YUCA PARA USO HUMANO EN UNA COMUNIDAD DE ECUADOR

Directory of Open Access Journals (Sweden)

Flor María Cárdenas Guillén

2015-06-01

Full Text Available El estudio tuvo por objetivo evaluar dos tipos de sistemas de secado de almidón de yuca (el secado tradicional al ambiente, sobre piso de cemento recubierto con polietileno negro de calibre número 6, y el eco tecnológico con armazón de madera, placa metálica y cubierta de vidrio. El trabajo se ejecutó en la comunidad de San Pablo de Tarugo, Chone-Manabí. Se construyó el secador solar y se lo adaptó a las condiciones de la zona. Para la medición del porcentaje de humedad del almidón, al ingreso y salida de ambos sistemas, se empleó el método convencional No. 925.09 AOAC. Se observó que el contenido de humedad inicial del almidón fluctúa entre 42,6% y 44,9%. Con el sistema de secado solar ecotecnológico, se registró temperaturas promedios de 31ºC y 60ºC, en la mañana y tarde, respectivamente. Igualmente, mediante el mismo sistema, se obtuvo el menor porcentaje de humedad de salida equivalente a 11,7%. Por lo tanto, el secador solar ecotecnológico es una opción viable en el secado del almidón de yuca, a pesar de las variaciones diarias del estado del tiempo.

A self-calibrating optomechanical force sensor with femtonewton resolution

International Nuclear Information System (INIS)

Melcher, John; Stirling, Julian; Pratt, Jon R.; Shaw, Gordon A.; Cervantes, Felipe Guzmán

2014-01-01

We report the development of an ultrasensitive optomechanical sensor designed to improve the accuracy and precision of force measurements with atomic force microscopy. The sensors reach quality factors of 4.3 × 10 6 and force resolution on the femtonewton scale at room temperature. Self-calibration of the sensor is accomplished using radiation pressure to create a reference force. Self-calibration enables in situ calibration of the sensor in extreme environments, such as cryogenic ultra-high vacuum. The senor technology presents a viable route to force measurements at the atomic scale with uncertainties below the percent level

A self-calibrating optomechanical force sensor with femtonewton resolution

Energy Technology Data Exchange (ETDEWEB)

Melcher, John, E-mail: john.melcher@nist.gov; Stirling, Julian; Pratt, Jon R.; Shaw, Gordon A. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Cervantes, Felipe Guzmán [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States)

2014-12-08

We report the development of an ultrasensitive optomechanical sensor designed to improve the accuracy and precision of force measurements with atomic force microscopy. The sensors reach quality factors of 4.3 × 10{sup 6} and force resolution on the femtonewton scale at room temperature. Self-calibration of the sensor is accomplished using radiation pressure to create a reference force. Self-calibration enables in situ calibration of the sensor in extreme environments, such as cryogenic ultra-high vacuum. The senor technology presents a viable route to force measurements at the atomic scale with uncertainties below the percent level.

Calibration of aerosol radiometers. Special aerosol sources

International Nuclear Information System (INIS)

Belkina, S.K.; Zalmanzon, Yu.E.; Kuznetsov, Yu.V.; Fertman, D.E.

1988-01-01

Problems of calibration of artificial aerosol radiometry and information-measurement systems of radiometer radiation control, in particular, are considered. Special aerosol source is suggested, which permits to perform certification and testing of aerosol channels of the systems in situ without the dismantling

In-situ calibration of RTDs and pressure sensors in nuclear power plants

International Nuclear Information System (INIS)

Hashemian, H.M.

1994-01-01

New techniques have been developed and validated for in-situ calibration of pressure transmitters as installed in nuclear power plants. These new techniques originate from a desire within the nuclear industry to monitor the calibration of pressure sensors during normal power operation by monitoring the DC output of the sensors for any significant draft and other anomalies. Currently, the calibration of pressure sensors is performed once every fuel cycle (18-24 months). The work involves significant manpower, radiation exposure to plant personnel, and potential damage to the plant equipment. In-situ calibration offers the potential to identify the sensors that need to be replaced or require calibration during normal plant operation, and reduce the calibration effort during outages to those sensors that need to be calibrated, as opposed to calibrating all the sensors

Calibration factor or calibration coefficient?

International Nuclear Information System (INIS)

Meghzifene, A.; Shortt, K.R.

2002-01-01

Full text: The IAEA/WHO network of SSDLs was set up in order to establish links between SSDL members and the international measurement system. At the end of 2001, there were 73 network members in 63 Member States. The SSDL network members provide calibration services to end-users at the national or regional level. The results of the calibrations are summarized in a document called calibration report or calibration certificate. The IAEA has been using the term calibration certificate and will continue using the same terminology. The most important information in a calibration certificate is a list of calibration factors and their related uncertainties that apply to the calibrated instrument for the well-defined irradiation and ambient conditions. The IAEA has recently decided to change the term calibration factor to calibration coefficient, to be fully in line with ISO [ISO 31-0], which recommends the use of the term coefficient when it links two quantities A and B (equation 1) that have different dimensions. The term factor should only be used for k when it is used to link the terms A and B that have the same dimensions A=k.B. However, in a typical calibration, an ion chamber is calibrated in terms of a physical quantity such as air kerma, dose to water, ambient dose equivalent, etc. If the chamber is calibrated together with its electrometer, then the calibration refers to the physical quantity to be measured per electrometer unit reading. In this case, the terms referred have different dimensions. The adoption by the Agency of the term coefficient to express the results of calibrations is consistent with the 'International vocabulary of basic and general terms in metrology' prepared jointly by the BIPM, IEC, ISO, OIML and other organizations. The BIPM has changed from factor to coefficient. The authors believe that this is more than just a matter of semantics and recommend that the SSDL network members adopt this change in terminology. (author)

Study on quantities of radiation protection in medical X-rays radiation field with polyhedron phantom

International Nuclear Information System (INIS)

Yuan Shuyu; Dai Guangfu; Zhang Liangan

1997-01-01

The author have studied tissue-equivalent material with the elemental composition recommended by report No.44 of ICRU. Three different calibration phantoms in shape have been prepared with the tissue-equivalent material in order to study the influence of the angular dependence factor R(d,α) in the radiation field of X-rays on the calibration of individual dose equivalent Hp(d). The requirement of mono-genous radiation field to calibrate several dosimeters on one phantom at the same time can be met by application of dodecahedron phantom, which is difficult on ICRU sphere. Angular dependence factor R(d,α) of 0 degree∼90 degree and conversion coefficients between individual dose equivalent Hp(0.07, α) and the exposure of radiation of different energies and different angles have been established by taking advantage of the dodecahedron. Besides, the authors have studied the variation relation between the individual dose equivalent Hp (10,α) and Hp(0.07,α) in the medical X-rays radiation field

Collection of abstracts. 6. national symposium on radiation dosimetry

International Nuclear Information System (INIS)

1983-08-01

Abstracts are given of the total of 137 papers presented at the symposium. The papers discussed radiation dosimetry methods, dosemeters and detectors, the metrology and calibration of radiation sources, calibration standards, and radioactivity monitoring. (J.P.)

Group: radiation dosimetry

International Nuclear Information System (INIS)

Caldas, L.V.E.

1990-01-01

The main activities of the radiation dosimetry group is described, including the calibration of instruments, sources and radioactive solutions and the determination of neutron flux; development, production and market dosimetric materials; development radiation sensor make the control of radiation dose received by IPEN workers; development new techniques for monitoring, etc. (C.G.C.)

Novel calibration system with sparse wires for CMB polarization receivers

International Nuclear Information System (INIS)

Tajima, O.; Nguyen, H.; Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A.

2011-01-01

B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature (∼10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

Calibration of the High Resolution Gamma Spectrometry Detection Systems from the Environmental Radioactivity Unit and Radiological Surveillance (ARU and RV); Calibracion de los Sistemas Detectores de Espectrometria Gamma de Alta Resolucion de la Unidad de Radiactividad Ambiental y Vigilancia Radiologica (URA y VR)

Energy Technology Data Exchange (ETDEWEB)

Suarez-Navarro, J. A.; Gasco, C.; Arana, M.; Suanez, A.

2012-11-01

In accordance with international regulations and with the quality criteria imposed by the internal quality system of the laboratory of gamma spectrometry, which belongs to the Unit of Environmental Radioactivity and Radiation Monitoring (URA y VR), it is necessary to perform a periodic calibration of the measurement systems of gamma spectrometry. The equipment calibration carries with the need for the preparation of the geometries of measurement and calibration in energy and in efficiencies. This report reflects the procedures for the preparation of the wide range of geometries available in the laboratory, as well as the different calibrations performed with those geometries in almost all the laboratory gamma detectors using the CANBERRA software Genie 2k. (Author) 9 refs.

Development of a calibration methodology and tests of kerma area product meters

International Nuclear Information System (INIS)

Costa, Nathalia Almeida

2013-01-01

The quantity kerma area product (PKA) is important to establish reference levels in diagnostic radiology exams. This quantity can be obtained using a PKA meter. The use of such meters is essential to evaluate the radiation dose in radiological procedures and is a good indicator to make sure that the dose limit to the patient's skin doesn't exceed. Sometimes, these meters come fixed to X radiation equipment, which makes its calibration difficult. In this work, it was developed a methodology for calibration of PKA meters. The instrument used for this purpose was the Patient Dose Calibrator (PDC). It was developed to be used as a reference to check the calibration of PKA and air kerma meters that are used for dosimetry in patients and to verify the consistency and behavior of systems of automatic exposure control. Because it is a new equipment, which, in Brazil, is not yet used as reference equipment for calibration, it was also performed the quality control of this equipment with characterization tests, the calibration and an evaluation of the energy dependence. After the tests, it was proved that the PDC can be used as a reference instrument and that the calibration must be performed in situ, so that the characteristics of each X-ray equipment, where the PKA meters are used, are considered. The calibration was then performed with portable PKA meters and in an interventional radiology equipment that has a PKA meter fixed. The results were good and it was proved the need for calibration of these meters and the importance of in situ calibration with a reference meter. (author)

The radiation environment in underground workplaces of the LHC

CERN Document Server

Theis, C; Kindl, Peter

2007-01-01

Active dose-monitoring of workplaces is crucial in order to operate a high-energy particle accelerator safely. As the mixed radiation fields that are expected in the environment of the Large Hadron Collider (LHC) are very different from standard use-cases like in nuclear power plants, it is of highest importance to characterize and calibrate radiation monitoring equipment appropriately for their use in high energy mixed radiation fields. Due to their sensitivity to different particle types over a larger energy range high-pressure ionization chambers have already been used at CERN and they are foreseen to be included within the radiation monitoring system of the LHC. In the framework of this thesis a new method was developed which allows for appropriate field-specific calibration of these detectors using Monte Carlo simulations. Therefore, the application of common 238Pu-Be source based calibration in mixed radiation fields was studied and compared to more accurate field specific calibration based on FLUKA Mon...

Quality assurance of radiation protection monitoring instruments in India

International Nuclear Information System (INIS)

Tripathi, S.M.; Daniel, Liji; Rao, Suresh; Sharma, D.N.

2008-01-01

Bhabha Atomic Research Centre (BARC) is the National Metrology Institute (NMI) for developing, maintaining and disseminating standards for ionizing radiation in India. Radiation Safety Systems Division (RSSD) of BARC has the requisite infrastructure in the form of experts, trained manpower, laboratories, equipment and facilities for providing calibration services to users and ascertaining traceability to international standards. It periodically participates in various international inter-comparisons. RSSD maintains reference radiation fields that are required for calibrating Radiation Protection Monitoring Instruments that form the backbone of the radiation monitoring programme for harnessing the benefits of nuclear energy and ionizing radiations. These instruments are type-tested and periodically calibrated at standard reference radiation fields to ensure their healthy working condition and fitness for their intended use. This paper describes the details of the standardization procedures adopted for reference radiation fields and infrastructure established and maintained at RSSD, BARC in accordance with the recommendations of ISO-4037. The paper describes the various tests that are carried out for radiation protection monitoring instrument to study the variation of the calibration factor with influencing quantities like linearity of response, energy response, angular dependence and overload characteristics. The results of these tests for typical instruments are also discussed. The present work also describes various types of indigenously developed radiation protection monitoring instruments and their performance characteristics. Adaptability of these instruments for the implementation of operational quantities are discussed briefly. It also dwells on the IAEA Quality Audit for radiation protection level calibrations, which RSSD has been participating since 2001. Our results of the quality audit are well within the acceptance limit (±7%) set by IAEA for the

Establishment of a new calibration method of pencil ionization chamber for dosimetry in computed tomography

International Nuclear Information System (INIS)

Dias, Daniel Menezes

2010-01-01

Pencil ionization chambers are used for beam dosimetry in computed tomography equipment (CT). In this study, a new calibration methodology was established, in order to make the Calibration Laboratory of Instituto de Pesquisas Energeticas e Nucleares (LCI) suitable to international metrological standards, dealing with specific procedures for calibration of these chambers used in CT. Firstly, the setup for the new RQT radiation qualities was mounted, in agreement with IEC61267 from the International Electrotechnical Commission (IEC). After the establishment of these radiation qualities, a specific calibration methodology for pencil ionization chambers was set, according to Technical Report Series No. 457, from the International Atomic Energy Agency (IAEA), which describes particularities of the procedure to be followed by the Secondary Standard Dosimetry Laboratories (SSDL's), concerning to collimation and positioning related to the radiation beam. Initially, PPV (kV) measurements and the determination of copper additional filtrations were carried out, measuring the half value layers (HVL) recommended by the IEC 61267 standard, after that the RQT 8, RQT 9 and RQT 10 radiation quality references were established. For additional filters, aluminum and copper of high purity (around 99.9%) were used. RQT's in thickness of copper filters equivalent to the set 'RQR (Al) + Additional Filtration (Cu)' was directly found by an alternative methodology used to determine additional filtrations, which is a good option when RQR's have not the possibility of be setting up. With the establishment of this new methodology for the ionization pencil chambers calibration, the LCI is ready to calibrate these instruments according to the most recent international standards. Therefore, an improvement in calibration traceability, as well as in metrological services offered by IPEN to all Brazil is achieved. (author)

Calibration of working standard ionization chambers and dose standardization

International Nuclear Information System (INIS)

Abd Elmahoud, A. A. B.

2011-01-01

Measurements were performed for the calibration of two working standard ionization chambers in the secondary standard dosimetry laboratory of Sudan. 600 cc cylindrical former type and 1800 cc cylindrical radical radiation protection level ionization chambers were calibrated against 1000 cc spherical reference standard ionization chamber. The chamber were calibrated at X-ray narrow spectrum series with beam energies ranged from (33-116 KeV) in addition to 1''3''7''Cs beam with 662 KeV energy. The chambers 0.6 cc and 0.3 cc therapy level ionization were used for dose standardization and beam output calibrations of cobalt-60 radiotherapy machine located at the National Cancer Institute, University of Gazira. Concerning beam output measurements for 6''0''Co radiotherapy machine, dosimetric measurements were performed in accordance with the relevant per IAEA dosimetry protocols TRS-277 and TRS-398. The kinetic energy released per unit mass in air (air kerma) were obtained by multiplying the corrected electrometer reading (nC/min) by the calibration factors (Gy/n C) of the chambers from given in the calibration certificate. The uncertainty of measurements of air kerma were calculated for the all ionization chambers (combined uncertainty) the calibration factors of these ionization chambers then were calculated by comparing the reading of air kerma of secondary standard ionization chambers to than from radical and farmer chambers. The result of calibration working standard ionization chambers showed different calibration factors ranged from 0.99 to 1.52 for different radiation energies and these differences were due to chambers response and specification. The absorbed dose to to water calculated for therapy ionization chamber using two code of practice TRS-277 and TRS-398 as beam output for 6''0''Co radiotherapy machine and it can be used as a reference for future beam output calibration in radiotherapy dosimetry. The measurement of absorbed dose to water showed that the

Calibration of radon-222 detectors using closed circuit radium-226 sources

International Nuclear Information System (INIS)

Perna, Allan Felipe Nunes; Paschuk, Sergei Anatolyevich; Correa, Janine Nicolosi; Del Claro, Flavia

2012-01-01

This paper presents the results of the calibration of the Radon-222 detectors used by the Laboratories specializing in measuring natural radiation from this gas. The research was conducted in collaboration between UTFPR, CDTN/CNEN, UFRN and IRD/CNEN. During the calibration the detectors were exposed in isolated chambers with radioactive calibrated sources. The calibration procedure was supported with four instant radon monitors AlphaGUARD (SAPHYMO Co.) responsible for radon activity measurements in the experimental chamber. The calibration procedure resulted an equation that relates the number of tracks found in solid-state detector CR-39 (Track-Etch detector) with the concentration of radon in the atmosphere. Obtained results are compatible with previously performed calibration at the National Institute of Radiological Sciences (NIRS, Japan) using high activity levels of radon in air. Present results of calibration give the possibility to expand the calibration curve of CR-39 for medium and low activity levels of radon. (author)

Sistemas roboticos teleoperados

Directory of Open Access Journals (Sweden)

Alexander Ceron Correa

2005-01-01

Full Text Available En el presente artículo se realiza una revisión general sobre los sistemas robóticos teleoperados, su estructura, componentes principales, clasificación, tipos de sensores, sistemas de locomoción y aplicaciones; como ejemplo se mencionan algunos trabajos realizados Colombia y en el mundo

History, organization, and oversight of the accredited dosimetry calibration laboratories by the AAPM

Energy Technology Data Exchange (ETDEWEB)

Rozenfeld, M. [St. James Hospital and Health Centers, Chicago Heights, IL (United States)

1993-12-31

For more than 20 years, the American Association of Physicists in Medicine (AAPM) has operated an accreditation program for secondary standards laboratories that calibrate radiation measuring instruments. Except for one short period, that program has been able to provide the facilities to satisfy the national need for accurate calibrations of such instruments. That exception, in 1981, due to the combination of the U.S. Nuclear Regulatory Commission (NRC) requiring instrument calibrations by users of cobalt-60 teletherapy units and the withdrawal of one of the three laboratories accredited at that time. However, after successful operation as a Task Group of the Radiation Therapy Committee (RTC) of the AAPM for two decades, a reorganization of this structure is now under serious consideration by the administration of the AAPM.

History, organization, and oversight of the accredited dosimetry calibration laboratories by the AAPM

International Nuclear Information System (INIS)

Rozenfeld, M.

1993-01-01

For more than 20 years, the American Association of Physicists in Medicine (AAPM) has operated an accreditation program for secondary standards laboratories that calibrate radiation measuring instruments. Except for one short period, that program has been able to provide the facilities to satisfy the national need for accurate calibrations of such instruments. That exception, in 1981, due to the combination of the U.S. Nuclear Regulatory Commission (NRC) requiring instrument calibrations by users of cobalt-60 teletherapy units and the withdrawal of one of the three laboratories accredited at that time. However, after successful operation as a Task Group of the Radiation Therapy Committee (RTC) of the AAPM for two decades, a reorganization of this structure is now under serious consideration by the administration of the AAPM

Calibration of an electron/proton monitor for the earth's radiation belt at 4 R/sub E/

International Nuclear Information System (INIS)

Higbie, P.R.; Belian, R.D.; Argo, H.V.; Baker, D.N.

1982-03-01

A charged particle dosimeter (the Burst Detector Dosimeter or BDD) was designed and fabricated and will be flown on certain of the Global Positioning Satellite (GPS) series of spacecraft. The BDD will monitor the dose received by the GPS spacecraft from the fluxes of electrons and protons in the Earth's radiation belt. The BDD uses absorbers in front of silicon sensors to determine the energy thresholds for measuring incident particle fluxes; and the magnitude of energy loss in a single sensor distinguishes between ions and electrons over a wide range of energies. Our electron calibrations were performed to determine accurately the energy response function of the dosimeter. The experimentally determined energy and angular responses are used to determine the equivalent energy thresholds and geometric factors for idealized step function responses

Calibration of the DLP-SC-3300-02 probe

DEFF Research Database (Denmark)

Pivnenko, Sergey; Breinbjerg, Olav

This report douments the calibration measurement of the DLP-SC-3300-02 dual-linearly polarized near-field probe. The measurement comprises radiation pattern, diretivity, gain, spetra of spherial wave coefients, polarization charateristis, and complex channel balance at 41 frequencies, as well...

The Importance of Calibration on Digital Radioscopy System

International Nuclear Information System (INIS)

Noorhazleena Azaman; Abdul Razak Hamzah; Sapizah Rahim

2011-01-01

Radiography testing is one of the non-destructive testing methods where it is used to detect discontinuities in a material by using x-ray and gamma ray as a sources of radiation. Mobile digital radioscopy system (MDRS) is act as a detector or medium to capture and convert the image in a real time and the image produced can view directly from the computer connected to the MDRS. Calibration is one of the factors that we need to consider in order to get the image and see in a high resolution and good contrast. The advantage of calibration in MDRS is to reduce and avoid from the noise. Calibration is not stable and the imaging system must be calibrated periodically. It is also as an alternative to the radiographic film to reduce and saving cost and time with considerable saving in running cost and processing time. (author)

Radiation practices. Annual report 2009

International Nuclear Information System (INIS)

Rantanen, E.

2010-08-01

1 742 safety licences for the use of radiation were current at the end of 2009. 1 820 responsible parties were engaged in notifiable licence-exempt dental X-ray activities. Use of radiation was controlled through regular inspections performed at places of use, test packages sent by post to dental X-ray facilities and maintenance of the Dose Register. Radiation safety guides were also published and research was conducted in support of regulatory control. The Radiation and Nuclear Safety Authority (STUK) conducted 414 inspections of licensed practices in 2009. 392 repair orders and recommendations were issued. A total of nearly 11 600 workers were subject to individual monitoring in 2009. Just under 160 000 dose entries were made in the Dose Register maintained by STUK. Regulatory control of natural radiation focused on radon at workplaces and exposure of aircrews to cosmic radiation. 108 workplaces including a total of 219 work areas were subject to radon monitoring during 2009. 3655 cockpit and cabin crew members were monitored for exposure to cosmic radiation. STUK took part in three major ionizing radiation research projects. An IAEA research project tested IAEA/WHO diagnostic dosimetry guidelines. The accuracy and reliability of internal and external radiotherapy dosimetric methods in modern radiotherapy technology was studied as part of a European metrology research programme. In metrological activities the calibration procedure for radiotherapy accelerator electron beam dosemeters was modified by changing from meter calibration in hospitals to laboratory calibration. Some irradiation appliances were also replaced. Calibration services continued as in previous years. Regulatory control of the use of non-ionizing radiation in 2009 focused particularly on mobile phones, sunbeds and lasers. Fifteen mobile phone types were tested in market surveillance of wireless communication devices. 19 sunbed facilities were inspected and ten laser display inspections were

Radiation practices. Annual report 2010

Energy Technology Data Exchange (ETDEWEB)

Rantanen, E. (ed.)

2011-07-01

1760 safety licences for the use of radiation were current at the end of 2010. 1789 responsible parties were engaged in notifiable licence-exempt dental X-ray activities. Use of radiation was controlled through regular inspections performed at places of use, test packages sent by post to dental X-ray facilities and maintenance of the Dose Register. Radiation safety guides were also published and research was conducted in support of regulatory control. The Radiation and Nuclear Safety Authority (STUK) conducted 384 inspections of licensed practices in 2010. 447 repair orders and recommendations were issued in the course of inspections. A total of nearly 12 100 workers were subject to individual monitoring in 2010. Just under 160 000 dose entries were made in the Dose Register maintained by STUK. Regulatory control of natural radiation focused on radon at workplaces and exposure of aircrews to cosmic radiation. 140 workplaces including a total of 348 work areas were subject to radon monitoring during 2010. 3428 cockpit and cabin crew members were monitored for exposure to cosmic radiation. STUK took part in three major ionizing radiation research projects. An IAEA research project tested diagnostic dosimetry guidelines. The accuracy and reliability of internal and external radiotherapy dosimetric methods in modern radiotherapy technology were studied as part of a European metrology research programme. In metrological activities the dosemeter calibration procedure for radiotherapy accelerator electron beams was modified by changing from meter calibrations in hospitals to laboratory calibrations. Some irradiation appliances were also replaced. Calibration services continued as in previous years. Regulatory control of the use of non-ionizing radiation in 2010 focused particularly on mobile phones, sunbeds and lasers. 16 sunbed facilities were inspected and 8 on-site laser display inspections were performed. Ten mobile phone types were tested in market surveillance of

The NIF x-ray spectrometer calibration campaign at Omega

Energy Technology Data Exchange (ETDEWEB)

Pérez, F.; Kemp, G. E.; Barrios, M. A.; Pino, J.; Scott, H.; Ayers, S.; Chen, H.; Emig, J.; Colvin, J. D.; Fournier, K. B., E-mail: fournier2@llnl.gov [Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551 (United States); Regan, S. P.; Bedzyk, M.; Shoup, M. J.; Agliata, A.; Yaakobi, B.; Marshall, F. J.; Hamilton, R. A. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Jaquez, J.; Farrell, M.; Nikroo, A. [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)

2014-11-15

The calibration campaign of the National Ignition Facility X-ray Spectrometer (NXS) was carried out at the OMEGA laser facility. Spherically symmetric, laser-driven, millimeter-scale x-ray sources of K-shell and L-shell emission from various mid-Z elements were designed for the 2–18 keV energy range of the NXS. The absolute spectral brightness was measured by two calibrated spectrometers. We compare the measured performance of the target design to radiation hydrodynamics simulations.

The NIF x-ray spectrometer calibration campaign at Omega.

Science.gov (United States)

Pérez, F; Kemp, G E; Regan, S P; Barrios, M A; Pino, J; Scott, H; Ayers, S; Chen, H; Emig, J; Colvin, J D; Bedzyk, M; Shoup, M J; Agliata, A; Yaakobi, B; Marshall, F J; Hamilton, R A; Jaquez, J; Farrell, M; Nikroo, A; Fournier, K B

2014-11-01

The calibration campaign of the National Ignition Facility X-ray Spectrometer (NXS) was carried out at the Omega laser facility. Spherically symmetric, laser-driven, millimeter-scale x-ray sources of K-shell and L-shell emission from various mid-Z elements were designed for the 2-18 keV energy range of the NXS. The absolute spectral brightness was measured by two calibrated spectrometers. We compare the measured performance of the target design to radiation hydrodynamics simulations.

Requirements for the authorization of operation os a calibration laboratory of gamma-ray monitors

International Nuclear Information System (INIS)

Silva, Raimundo Dias da; Kibrit, Eduardo

2011-01-01

This paper describes the process for obtaining the authorization of operation of a laboratory designed to calibrate area and personal monitors with gamma radiation, by using a sealed Cs-137 source. The regulations of Comissao Nacional de Energia Nuclear (CNEN) are deeply analysed and discussed. The authorization for construction, the authorization for modification of items important to safety, the authorization for the acquisition and handling of radiation sources, the authorization for operating, and the authorization for withdrawal of operation of the laboratory are also discussed. The paper also describes the technical and managerial requirements necessary to operate a gamma radiation calibration laboratory in Brazil. . (author)

High dose calibrations at the Pacific Northwest Laboratory

International Nuclear Information System (INIS)

McDonald, J.C.; Fox, R.A.

1988-10-01

The need is increasing for both high radiation exposures and calibration measurements that provide traceability of such exposures to national standards. The applications of high exposures include: electronic component damage studies, sterilization of medical products and food irradiation. Accurate high exposure measurements are difficult to obtain and cannot, in general, be carried out with a single dose measurement system or technique because of the wide range of doses and the variety of materials involved. This paper describes the dosimetric measurement and calibration techniques used at the Pacific Northwest Laboratory (PNL) that make use of radiochromic dye films, thermoluminescent dosimeters (TLDs), ionization chambers, and calorimetric dosimeters. The methods used to demonstrate the consistency of PNL calibrations with national standards will also be discussed. 4 refs

Non-uniformity calibration for MWIR polarization imagery obtained with integrated microgrid polarimeters

Science.gov (United States)

Liu, Hai-Zheng; Shi, Ze-Lin; Feng, Bin; Hui, Bin; Zhao, Yao-Hong

2016-03-01

Integrating microgrid polarimeters on focal plane array (FPA) of an infrared detector causes non-uniformity of polarization response. In order to reduce the effect of polarization non-uniformity, this paper constructs an experimental setup for capturing raw flat-field images and proposes a procedure for acquiring non-uniform calibration (NUC) matrix and calibrating raw polarization images. The proposed procedure takes the incident radiation as a polarization vector and offers a calibration matrix for each pixel. Both our matrix calibration and two-point calibration are applied to our mid-wavelength infrared (MWIR) polarization imaging system with integrated microgrid polarimeters. Compared with two point calibration, our matrix calibration reduces non-uniformity by 30 40% under condition of flat-field data test with polarization. The ourdoor scene observation experiment indicates that our calibration can effectively reduce polarization non-uniformity and improve the image quality of our MWIR polarization imaging system.

Calibrating an optical scanner for quality assurance of large area radiation detectors

Science.gov (United States)

Karadzhinova, A.; Hildén, T.; Berdova, M.; Lauhakangas, R.; Heino, J.; Tuominen, E.; Franssila, S.; Hæggström, E.; Kassamakov, I.

2014-11-01

A gas electron multiplier (GEM) is a particle detector used in high-energy physics. Its main component is a thin copper-polymer-copper sandwich that carries Ø =70  ±  5 µm holes. Quality assurance (QA) is needed to guarantee both long operating life and reading fidelity of the GEM. Absence of layer defects and conformity of the holes to specifications is important. Both hole size and shape influence the detector’s gas multiplication factor and hence affect the collected data. For the scanner the required lateral measurement tolerance is ± 5 µm. We calibrated a high aspect ratio optical scanning system (OSS) to allow ensuring the quality of large GEM foils. For the calibration we microfabricated transfer standards, which were imaged with the OSS and which were compared to corresponding scanning electron microscopy (SEM) images. The calibration fulfilled the ISO/IEC 17025 and UKAS M3003 requirements: the calibration factor was 1.01  ±  0.01, determined at 95% confidence level across a 950  ×  950 mm2 area. The proposed large-scale scanning technique can potentially be valuable in other microfabricated products too.

Measurement of TLD Albedo response on various calibration phantoms

International Nuclear Information System (INIS)

Momose, T.; Tsujimura, N.; Shinohara, K.; Ishiguro, H.; Nakamura, T.

1996-01-01

The International Commission on Radiation Units and Measurements (ICRU) has recommended that individual dosemeter should be calibrated on a suitable phantom and has pointed out that the calibration factor of a neutron dosemeter is strongly influenced by the the exact size and shape of the body and the phantom to which the dosemeter is attached. As the principle of an albedo type thermoluminescent personal dosemeter (albedo TLD) is essentially based on a detection of scattered and moderated neutron from a human body, the sensitivity of albedo TLD is strongly influenced by the incident neutron energy and the calibration phantom. (1) Therefore for albedo type thermoluminescent personal dosemeter (albedo TLD), the information of neutron albedo response on the calibration phantom is important for appropriate dose estimation. In order to investigate the effect of phantom type on the reading of the albedo TLD, measurement of the TLD energy response and angular response on some typical calibration phantoms was performed using dynamitron accelerator and 252 Cf neutron source. (author)

ISO radiation protection standards

International Nuclear Information System (INIS)

Becker, K.; West, N.

1981-01-01

After a brief description of the International Organization for Standardization (ISO) and its Technical Committee (TC) 85 ''Nuclear Energy'', the work of its Sub-Committee (SC) 2 ''Radiation Protection'' is described in some detail. Several international standards on subjects closely related to radiation protection have already been published, for example ISO-361 (Basic radiation protection symbol), ISO-1757 (Photographic dosimeters), ISO-1758 and 1759 (Direct and indirect-reading pocket exposure meters), ISO-2889 (Sampling of airborne radioactive materials), ISO-4037 (X and gamma reference radiations for calibration) and ISO-4071 (Testing of exposure meters and dosimeters). TC 85/SC 2 has currently eight active Working Groups (WG) dealing with 14 standards projects, mostly in advanced stages, in such fields as neutron and beta reference radiations, and X and gamma radiations of high and low dose-rates and high energies for calibration purposes, reference radiations for surface contamination apparatus, ejection systems for gamma radiography apparatus, industrial and laboratory irradiators, lead shielding units, protective clothing, thermoluminescence dosemeters, radioelement gauges, and surface contamination and decontamination. (author)

Regulación neuroendocrina del sistema inmune

OpenAIRE

Caballero Hernández, Diana; Tamez Guerra, Reyes S.; Rodríguez Padilla, Cristina; Tamez Guerra, Patricia; Weber, Richard J.; Gómez Flores, Ricardo

2001-01-01

El sistema inmune recibe señales del sistema nervioso central (cerebro) vía el sistema nervioso autónomo y el sistema endocrino. El sistema inmune, a su vez, envía información al cerebro vía citocinas. Este sistema de retroalimentación es vital para el funcionamiento adecuado del organismo en situaciones normales, y en aquellas en las que la homeostasis se ve perturbada, como en casos de estrés, consumo de drogas (terapéuticas o de abuso), enfermedades infecciosas y...

Effective radiation attenuation calibration for breast density: compression thickness influences and correction

OpenAIRE

Thomas Jerry A; Cao Ke; Heine John J

2010-01-01

Abstract Background Calibrating mammograms to produce a standardized breast density measurement for breast cancer risk analysis requires an accurate spatial measure of the compressed breast thickness. Thickness inaccuracies due to the nominal system readout value and compression paddle orientation induce unacceptable errors in the calibration. Method A thickness correction was developed and evaluated using a fully specified two-component surrogate breast model. A previously developed calibrat...

Safety enhancement through calibration and maintenance

International Nuclear Information System (INIS)

Mohammad Ali Khalid; Taiman Kadni

2000-01-01

Although radiation causes an alarming effect to living organism, it has been accepted for diagnostic and therapy in medicine as well as quality control and test method in industry. Due to the benefit gained, public at large is willing to accept the risk on condition that proper protection and safety standard is implemented and practised. Instrument plays a very important role not only in generation radiation but also measuring it. Therefore to ensure safety it is fair to say that all instrument must be calibrated to a certain standard and maintained to operate to its design specifications from time to time. (author)

Novel calibration system with sparse wires for CMB polarization receivers

Energy Technology Data Exchange (ETDEWEB)

Tajima, O.; /KEK, Tsukuba /Chicago U., KICP; Nguyen, H.; /Fermilab; Bischoff, C.; /Chicago U., KICP /Harvard-Smithsonian Ctr. Astrophys.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP

2011-07-01

B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature ({approx}10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

Sistemas de gestión ambiental normalizados

OpenAIRE

Fronti de García, Luisa; Pahlen, Ricardo José María; D’Onofrio, Paula Alejandra

2004-01-01

La contabilidad ambiental presupone la existencia de un sistema de gestión ambiental. Dentro del sistema integral de la organización, el sistema de gestión ambiental permite la obtención de información oportuna y segura. Podríamos definir el sistema de gestión ambiental de un ente como el conjunto de medidas destinadas a prevenir el impacto negativo de las actividades del ente sobre el medio ambiente. El sistema de gestión ambiental (SGA) es aquella parte del sistema de gestión total que incl...

Exercise of laboratory comparison for contamination monitor calibration between LNMRI/IRD and LCR/UERJ - 2016

International Nuclear Information System (INIS)

Cabral, T.S.; David, M.

2016-01-01

This work was motivated by the need to decide on the best methodology to be applied in the next contamination monitor calibration comparisons with the Brazilian network of calibration radiation monitors. The calibration factor was chosen as a response calibration performed in the four monitors used in this comparison because it does not require the detector area or probe thereby reducing an important variable. It was observed that the variation of the positioning system may have an influence up to 10% in calibration. The results obtained for the calibration factor showed a difference of up to 31.2%. (author)

Advisory Committee for the calibration standards of ionizing radiation measurement

International Nuclear Information System (INIS)

1979-01-01

The meeting consisted exceptionally of two sessions (in May and December 1977). The members discussed the comparisons of absorbed dose standards and exposure standards which had taken place since 1975 and suggested improvements for future comparisons. A recommendation was made concerning the humidity correction factor to be applied when using cavity chambers and free-air chambers. Further studies were requested concerning the effective point of measurement of ionization chambers. No method was recommended for the statement of uncertainty in calibration certificates. The exposure standards and calibrations in terms of exposure were maintained but it was agreed that other possibilities should be explored. Finally, progress reports of the national laboratories and a description of the recent work carried out at BIPM were presented and appear as appendices to the report [fr

Development of radio frequency (RF) and microwave (MW) calibration facility using GTEM cell

International Nuclear Information System (INIS)

Rozaimah Abd Rahim; Mohd Yusof Mohd Ali; Mohd Anuar Abd Majid

2005-01-01

Recent studies indicate that non ionizing radiation (NIR) can cause health effect on human beings. Usage of equipment/machine/system in industrial sector, medical fields, surveillance, telecommunication, broadcast, weather forecast and some consumer product that can produced NIR attract public concern about the potential hazard cause by this radiation. It increases public demands on the use of suitable equipment/survey meters for measuring NIR radiation from such sources. This equipment/survey meters need to be calibrated to insure that the equipment/survey meters give correct, accurate and precise reading. One of the systems that can be used to do the calibration work is GTEM cell. GTEM cell can also be used to perform tests involving electromagnetic fields such as electromagnetic compatibility test (EMC), electromagnetic immunity or susceptibility test (EMS) and electromagnetic interference test (EMI). This paper highlights some of the work that had been carried out to map out the field strengths within the GTEM cell and test results of some of the calibration work performed on RF measuring instrument. (Author)

Traceability of radiation measurements: musings of a user

International Nuclear Information System (INIS)

Kathren, R.L.

1980-04-01

Although users of radiation desire measurement traceability for a number of reasons, including legal, regulatory, contractual, and quality assurance requirements, there exists no real definition of the term in the technical literature. Definitions are proposed for both traceability and traceability to the National Bureau of Standards. The hierarchy of radiation standards is discussed and allowable uncertainties are given for each level. Areas of need with respect to radiation standards are identified, and a system of secondary radiation calibration laboratories is proposed as a means of providing quality calibrations and traceability on a routine basis

Traceability of radiation measurements: musings of a user

Energy Technology Data Exchange (ETDEWEB)

Kathren, R.L.

1980-04-01

Although users of radiation desire measurement traceability for a number of reasons, including legal, regulatory, contractual, and quality assurance requirements, there exists no real definition of the term in the technical literature. Definitions are proposed for both traceability and traceability to the National Bureau of Standards. The hierarchy of radiation standards is discussed and allowable uncertainties are given for each level. Areas of need with respect to radiation standards are identified, and a system of secondary radiation calibration laboratories is proposed as a means of providing quality calibrations and traceability on a routine basis.

Improving integrity of on-line grammage measurement with traceable basic calibration.

Science.gov (United States)

Kangasrääsiö, Juha

2010-07-01

The automatic control of grammage (basis weight) in paper and board production is based upon on-line grammage measurement. Furthermore, the automatic control of other quality variables such as moisture, ash content and coat weight, may rely on the grammage measurement. The integrity of Kr-85 based on-line grammage measurement systems was studied, by performing basic calibrations with traceably calibrated plastic reference standards. The calibrations were performed according to the EN ISO/IEC 17025 standard, which is a requirement for calibration laboratories. The observed relative measurement errors were 3.3% in the first time calibrations at the 95% confidence level. With the traceable basic calibration method, however, these errors can be reduced to under 0.5%, thus improving the integrity of on-line grammage measurements. Also a standardised algorithm, based on the experience from the performed calibrations, is proposed to ease the adjustment of the different grammage measurement systems. The calibration technique can basically be applied to all beta-radiation based grammage measurements. 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Calibration Uncertainties in the Droplet Measurement Technologies Cloud Condensation Nuclei Counter

Science.gov (United States)

Hibert, Kurt James

Cloud condensation nuclei (CCN) serve as the nucleation sites for the condensation of water vapor in Earth's atmosphere and are important for their effect on climate and weather. The influence of CCN on cloud radiative properties (aerosol indirect effect) is the most uncertain of quantified radiative forcing changes that have occurred since pre-industrial times. CCN influence the weather because intrinsic and extrinsic aerosol properties affect cloud formation and precipitation development. To quantify these effects, it is necessary to accurately measure CCN, which requires accurate calibrations using a consistent methodology. Furthermore, the calibration uncertainties are required to compare measurements from different field projects. CCN uncertainties also aid the integration of CCN measurements with atmospheric models. The commercially available Droplet Measurement Technologies (DMT) CCN Counter is used by many research groups, so it is important to quantify its calibration uncertainty. Uncertainties in the calibration of the DMT CCN counter exist in the flow rate and supersaturation values. The concentration depends on the accuracy of the flow rate calibration, which does not have a large (4.3 %) uncertainty. The supersaturation depends on chamber pressure, temperature, and flow rate. The supersaturation calibration is a complex process since the chamber's supersaturation must be inferred from a temperature difference measurement. Additionally, calibration errors can result from the Kohler theory assumptions, fitting methods utilized, the influence of multiply-charged particles, and calibration points used. In order to determine the calibration uncertainties and the pressure dependence of the supersaturation calibration, three calibrations are done at each pressure level: 700, 840, and 980 hPa. Typically 700 hPa is the pressure used for aircraft measurements in the boundary layer, 840 hPa is the calibration pressure at DMT in Boulder, CO, and 980 hPa is the

Calibration of the degree of linear polarization measurements of the polarized Sun-sky radiometer based on the POLBOX system.

Science.gov (United States)

Li, Zhengqiang; Li, Kaitao; Li, Li; Xu, Hua; Xie, Yisong; Ma, Yan; Li, Donghui; Goloub, Philippe; Yuan, Yinlin; Zheng, Xiaobing

2018-02-10

Polarization observation of sky radiation is the frontier approach to improve the remote sensing of atmospheric components, e.g., aerosol and clouds. The polarization calibration of the ground-based Sun-sky radiometer is the basis for obtaining accurate degree of linear polarization (DOLP) measurement. In this paper, a DOLP calibration method based on a laboratory polarized light source (POLBOX) is introduced in detail. Combined with the CE318-DP Sun-sky polarized radiometer, a calibration scheme for DOLP measurement is established for the spectral range of 440-1640 nm. Based on the calibration results of the Sun-sky radiometer observation network, the polarization calibration coefficient and the DOLP calibration residual are analyzed statistically. The results show that the DOLP residual of the calibration scheme is about 0.0012, and thus it can be estimated that the final DOLP calibration accuracy of this method is about 0.005. Finally, it is verified that the accuracy of the calibration results is in accordance with the expected results by comparing the simulated DOLP with the vector radiative transfer calculations.

Control console of the gamma calibration room; Consola de control de la Sala de Calibracion Gamma

Energy Technology Data Exchange (ETDEWEB)

Vilchis P, A.E.; Romero G, M. [Instituto Nacional de Investigaciones Nucleares, Ingenieria Electronica, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

1999-07-01

The Nuclear Centre of Mexico has a Ionizing Radiation Metrology Center (CMRI). This is in charge of the calibration in Mexico and Latin America of equipment dedicated to radiation measurement as industrial, medical as other fields. The importance to ensure that the equipment stay justly calibrated, it is imposed the necessity of automating the different rooms which the CMRI has. in this case it will be exposed the Calibration room for gamma radiation type. The operation of this application was carried out with the LabVIEW development platform and also in C language. The hardware associated is: personal computer with two cards using the 8255 device, 16 channels with optical isolation to manage input/output TTL type, 16 channels with optical isolation to management of charges to 127 V a.c., and 2 channels for 90V d.c. motors. (Author)

Studies on dosimetric tests applying source irradiation force of Cs-137 for using in chambers for calibration and TLD type dosimeters

International Nuclear Information System (INIS)

Ribeiro, Laila Lorena X.; Barbosa, Rugles Cesar; Correa, Rosangela S.

2011-01-01

The West Central region of Brazil does not have a basic infrastructure for research, development, training programs, and personnel dosimetry education. All of them applied to environmental, industrial and medical uses. Service deployment for irradiance of TLD, via 137 Cs irradiator J. L. SHEPHERD model 28-8A (444 activity GBq) in CRCN-CO, it is necessary to introduce procedures for calibration of the radiator and other procedures related to dosimetry and calibration. Such procedures should be repeated periodically, as necessary to introduce techniques that make the service of the CRCN-CO a template, and that meet all standards requirements for radioprotection and operation of dosimetry and calibration. The objective of this work was to evaluate the radiation field of Cs-137, and the automatic system which systematizes the calibration procedures attached to a system control target for the radiator/calibration of monitors, and portable dosimeters. (author)

A first in-flight absolute calibration of the Chilean Earth Observation Satellite

Science.gov (United States)

Mattar, C.; Hernández, J.; Santamaría-Artigas, A.; Durán-Alarcón, C.; Olivera-Guerra, L.; Inzunza, M.; Tapia, D.; Escobar-lavín, E.

2014-06-01

This work describes the first in-flight absolute calibration of the "Sistema Satelital para la Observación de la Tierra" (SSOT or Fasat-C). It was performed on January 29th 2013 at Antumapu site located in the southern area of Santiago, Chile. A description of the procedure is presented which includes both ground measurement and atmospheric characterization. The Chilean satellite for Earth observation carries on board a "New AstroSat Optical Modular Instrument" (NAOMI) high-resolution pushbroom imager which provides a 1.45 m ground sampling distance in the panchromatic (0.455-0.744 μm) channel and a 5.8 m ground sampling distance for the green (0.455-0.52 μm), blue (0.528-0.588 μm), red (0.625-0.695 μm) and near-infrared (0.758-0.881 μm) channels from a 620 km orbit. Radiometric calibration was carried out in order to estimate the land leaving radiance and bidirectional reflectance at the top of the atmosphere. To correct the reflectance data for atmospheric effects, the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) code was used. Aerosol Optical Depth (AOD), water vapor and ozone content were obtained from MOD04, MOD05 and MOD07 products respectively, which are derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) data. Statistical results such as BIAS, SIGMA and RMSE were calculated for the comparison between surface reflectance values and in situ measurements. Results show that the overall accuracy of the atmospherically corrected surface reflectance calculated from Fasat-C imagery can be estimated to around ±5%, with a R2 coefficient of 0.939 between atmospherically corrected reflectance values and in situ measurements. The atmospheric correction applied in this work by combining MODIS data and the 6S radiative transfer code could be used for further calibration of the Fasat-C images, although in situ atmospheric irradiance measurements are necessary to estimate reliable values of surface reflectance. Future

Calibration curves for biological dosimetry; Curvas de calibracion para dosimetria biologica

Energy Technology Data Exchange (ETDEWEB)

Guerrero C, C.; Brena V, M. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)]. E-mail cgc@nuclear.inin.mx

2004-07-01

The generated information by the investigations in different laboratories of the world, included the ININ, in which settles down that certain class of chromosomal leisure it increases in function of the dose and radiation type, has given by result the obtaining of calibrated curves that are applied in the well-known technique as biological dosimetry. In this work is presented a summary of the work made in the laboratory that includes the calibrated curves for gamma radiation of {sup 60} Cobalt and X rays of 250 k Vp, examples of presumed exposure to ionizing radiation, resolved by means of aberration analysis and the corresponding dose estimate through the equations of the respective curves and finally a comparison among the dose calculations in those people affected by the accident of Ciudad Juarez, carried out by the group of Oak Ridge, USA and those obtained in this laboratory. (Author)

Noninvasive method for the calibration of the peak voltage (kVp) meters

International Nuclear Information System (INIS)

Macedo, E.M.; Navarro, M.V.T.; Pereira, L.; Garcia, I.F.M.; Navarro, V.C.C.

2015-01-01

Quality control in diagnostic radiology is one of the mechanisms that minimize radiation exposure, and the measurement of tube voltage is one of the main test in these procedures. So, the calibration of non-invasive tube voltage meters is essential to maintain the metrological reliability of quality control tests. Thus, this work describes the implementation of the calibration methodology of the quantity tube peak voltage by the substitution method, using non-invasive standard meter, at LABPROSAUD-IFBA. The results showed great performance and when compared with calibrations by invasive methods, showed maximum difference of 4%, contemplated in the uncertainty ranges of the calibrations. (author)

Method for calibration of an axial tomographic scanner

International Nuclear Information System (INIS)

Sparks, R.A.

1977-01-01

The method of calibrating an axial tomographic scanner including frame means having an opening therein in which an object to be examined is to be placed, source and detector means mounted on the frame means for directing one or more beams of penetrating radiation through the object from the source to the detector means, and means to rotate the scanner including the source and detector means about the object whereby a plurality of sets of data corresponding to the transmission or absorption by the object of a plurality of beams of penetrating radiation are collected; the calibration method comprising mounting calibration means supporting an adjustable centering member onto the frame means, positioning the adjustable centering member at approximately the center of rotation of the scanner, placing position-sensitive indicator means adjacent the approximately centered member, rotating the scanner and the calibration means mounted thereon at least one time and, if necessary, adjusting the positioning of the centering member until the centering member is coincident with the center of rotation of the scanner as determined by minimum deflection of the position-sensitive indicator means, rotating and translating the source and detector means and determining for each angular orientation of the frame means supporting the source and detector means the central position of each translational scan relative to the centered member and/or if a plurality of detectors are utilized with the detector means for each planar slice of the object being examined, the central position of each translational scan for each detector relative to the centered member

Exercise for laboratory comparison of calibration coefficient in {sup 137}Cs beam, radiation protection - 2013/2014; Exercicio de comparacao laboratorial do coeficiente de calibracao em feixe de Cesio-137, radioprotecao - 2013/2014

Energy Technology Data Exchange (ETDEWEB)

Cabral, T.S. [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Potiens, M.P.A., E-mail: tschirn@ird.gov.br [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Soares, C.M.A. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Silveira, R.R. [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Khoury, H. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Fernandes, E. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Laboratorio de Ciencias Radiologicas; Cardoso, W.F. [Eletrobras Termonuclear S.A. (Eletronuclear), Rio de Janeiro, RJ (Brazil); Borges, J.C. [MRA Comercio de Instrumentos Eletronicos Ltda., Ribeirao Preto, SP (Brazil)

2015-07-01

This work deals with the preliminary results of the second exercise of comparing the radiation monitors calibration laboratories in Brazil. The exercise involved eight laboratories and the measured quantity is the air kerma in a beam of {sup 137}Cs for radioprotection. The exercise was conducted by the LNMRI/IRD, in a star shaped arrangement from October 2013 to July 2015. The largest deviation was 2% of the calibration coefficient that is acceptable for applications in radioprotection. (author)

Method and apparatus for neutron radiation monitoring

International Nuclear Information System (INIS)

Schwarzmann, A.

1985-01-01

A self-calibrated neutron radiation monitor includes a flux responsive element comprised of intrinsic silicon neutron detectors and self-calibration resistors in a single structure. As the resistance of the flux responsive element increases to the value of successive calibration resistors, known increments of flux have been encountered

Calibration facilities at Hanford for gamma-ray and fission-neutron well logging

International Nuclear Information System (INIS)

Stromswold, D.C.

1994-07-01

Well-logging tools that detect gamma rays emitted from earth formations need to be calibrated in appropriate facilities to provide quantitative assessments of concentrations o radionuclides based on detected gamma rays. These facilities are typically special models having a hole to insert tools and having sufficient physical size to simulate actual earth formations containing known amounts of radionuclides. The size, generally 3 to 5 feet in diameter and 4 to 6 feet tall, is such that the source of radiation appears infinite in extent to a tool detecting the radiation inside the model. Such models exist at Hanford as concrete cylinders having a central borehole and containing known, enhanced amounts of K, U, and Th. Data collected in these models allow calibration of the logging system to measure radionuclide concentrations in formations around boreholes in the field. The accuracy of the calculated field concentrations depends on the correctness of the original calibration, the statistical precision of the data, and the similarity of the logging conditions to the calibration conditions. Possible methods for analyzing the data collected in the calibration facilities are presented for both spectral and total-count gamma-ray systems. Corrections are typically needed for the effects of steel casing in boreholes and the presence of water rather than air in the holes. Data collected in the calibration models with various steel casings and borehole fluids allow such correction factors to be determined

Implementação de um sistema SIP para o sistema operacional Linux

OpenAIRE

Davison Gonzaga da Silva

2003-01-01

Resumo: Este trabalho apresenta a implementação de um Sistema de VoIP usando o Protocolo SIP. Este Sistema SIP foi desenvolvido para o Linux, usando-se a linguagem C++ em conjunto com a biblioteca QT. O Sistema SIP é composto de três entidades básicas: o Terminal SIP, o Proxy e o Servidor de Registros. O Terminal SIP é a entidade responsável por estabelecer sessões SIP com outros Terminais SIP. Para o Terminal SIP, foi desenvolvida uma biblioteca de acesso à placa de áudio, que permite a modi...

Results of L3 BGO calorimeter calibration using an RFQ accelerator

CERN Document Server

Chaturvedi, U K; Gataullin, M; Gratta, Giorgio; Kirkby, D; Lu, W; Newman, H; Shvorob, A V; Tully, C; Zhu, R

2000-01-01

A novel calibration system based on a radiofrequency-quadrupole (RFQ) accelerator has been installed in the L3 experiment. Radiative capture of 1.85 MeV protons from the RFQ accelerator in a lithium target produces a flux of 17.6 MeV photons which are used to calibrate 11000 crystals of the L3 BGO calorimeter. In this paper we present results of the RFQ run taken in November 1997. A calibration precision of 0.6% was reached in the barrel of the L3 BGO calorimeter, and 0.7% in the BGO endcaps. (8 refs).

External dosimetry - Applications to radiation protection

International Nuclear Information System (INIS)

Faussot, Alain

2011-01-01

Dosimetry is the essential component of radiation protection. It allows to determine by calculation and measurement the absorbed dose value, i.e. the energy amounts deposited in matter by ionizing radiations. It deals also with the irradiation effects on living organisms and with their biological consequences. This reference book gathers all the necessary information to understand and master the external dosimetry and the metrology of ionizing radiations, from the effects of radiations to the calibration of radiation protection devices. The first part is devoted to physical dosimetry and allows to obtain in a rigorous manner the mathematical formalisms leading to the absorbed dose for different ionizing radiation fields. The second part presents the biological effects of ionizing radiations on living matter and the determination of a set of specific radiation protection concepts and data to express the 'risk' to develop a radio-induced cancer. The third part deals with the metrology of ionizing radiations through the standardized study of the methods used for the calibration of radiation protection equipments. Some practical exercises with their corrections are proposed at the end of each chapter

Traceability of radiation protection instruments

Science.gov (United States)

Hino, Y.; Kurosawa, T.

2007-08-01

Radiation protection instruments are used in daily measurement of dose and activities in workplaces and environments for safety management. The requirements for calibration certificates with traceability are increasing for these instruments to ensure the consistency and reliabilities of the measurement results. The present traceability scheme of radiation protection instruments for dose and activity measurements is described with related IEC/ISO requirements. Some examples of desirable future calibration systems with recent new technologies are also discussed to establish the traceability with reasonable costs and reliabilities.

Comparison between calibration methods of ionization chamber type pencil in greatness P_K_L

International Nuclear Information System (INIS)

Macedo, E.M.; Pereira, L.C.S.; Ferreira, M.J.; Navarro, V.C.C.; Garcia, I.F.M.; Pires, E.J.; Navarro, M.V.T.

2016-01-01

Calibration of radiation meters is indispensable on Quality Assurance Program in Radiodiagnostic procedures, mainly Computed Tomography. Thus, this study aims evaluate two calibration methods of pencil ionization chambers in terms of Kerma-length Product (P_K_L) (a direct substitution method and an indirect one, through Kerma and length measurements). The results showed a good equivalence, with minimal concordance of 98,5% between calibration factors. About uncertainties, both showed similar results (substitution 2.2% and indirect 2.3%), indicating that the last one is better, due the costs reduction to implant this calibration procedure. (author)

El sistema deportivo. Amenazas y oportunidades

Directory of Open Access Journals (Sweden)

Javier Olivera Betrán

2006-06-01

Full Text Available Aplicando la teoría de sistemas de Ludwig von Bertalanffy, el deporte es un sistema. En un sistema se da un conjunto de unidades interrelacionadas de tal manera que el comportamiento de cada parte depende del estado de todas las otras, pues todas se encuentran en una estructura que las interconecta. En el enfoque sistémico, el concepto tradicional de energía es reemplazado por el de información, y el de causa-efecto por el de estructura y realimentación. El deporte es una realidad social total, por lo que participa de manera implícita y/o explícita en los procesos humanos más diversos a través de los distintos procedimientos que corresponden a nuestra organización sociocultural. El deporte se configura en estructuras de alta complejidad, las cuales están constituidas por sistemas de sistemas cuya comprensión y estudio representan un formidable reto. El estudio del deporte como sistema debe efectuarse desde la lógica estructural y sistémica a través de la cual nos permita indagar con éxito su configuración esencial, sus elementos fundamentales y el proceso de interactuación con los subsistemas que pertenecen al sistema deporte y con los otros del sistema sociocultural dominante. El deporte es un sistema dinámico que interactúa continuamente mediante un doble proceso, intrínseco a través de una constante metamorfosis entre los distintos subsistemas que lo integran y extrínseco por medio de un ajuste permanente con el contexto social, cultural y medioambiental.

Calibration of RB reactor power

International Nuclear Information System (INIS)

Sotic, O.; Markovic, H.; Ninkovic, M.; Strugar, P.; Dimitrijevic, Z.; Takac, S.; Stefanovic, D.; Kocic, A.; Vranic, S.

1976-09-01

The first and only calibration of RB reactor power was done in 1962, and the obtained calibration ratio was used irrespective of the lattice pitch and core configuration. Since the RB reactor is being prepared for operation at higher power levels it was indispensable to reexamine the calibration ratio, estimate its dependence on the lattice pitch, critical level of heavy water and thickness of the side reflector. It was necessary to verify the reliability of control and dosimetry instruments, and establish neutron and gamma dose dependence on reactor power. Two series of experiments were done in June 1976. First series was devoted to tests of control and dosimetry instrumentation and measurements of radiation in the RB reactor building dependent on reactor power. Second series covered measurement of thermal and epithermal neuron fluxes in the reactor core and calculation of reactor power. Four different reactor cores were chosen for these experiments. Reactor pitches were 8, 8√2, and 16 cm with 40, 52 and 82 fuel channels containing 2% enriched fuel. Obtained results and analysis of these results are presented in this document with conclusions related to reactor safe operation

PLEIADES ABSOLUTE CALIBRATION : INFLIGHT CALIBRATION SITES AND METHODOLOGY

Directory of Open Access Journals (Sweden)

S. Lachérade

2012-07-01

Full Text Available In-flight calibration of space sensors once in orbit is a decisive step to be able to fulfil the mission objectives. This article presents the methods of the in-flight absolute calibration processed during the commissioning phase. Four In-flight calibration methods are used: absolute calibration, cross-calibration with reference sensors such as PARASOL or MERIS, multi-temporal monitoring and inter-bands calibration. These algorithms are based on acquisitions over natural targets such as African deserts, Antarctic sites, La Crau (Automatic calibration station and Oceans (Calibration over molecular scattering or also new extra-terrestrial sites such as the Moon and selected stars. After an overview of the instrument and a description of the calibration sites, it is pointed out how each method is able to address one or several aspects of the calibration. We focus on how these methods complete each other in their operational use, and how they help building a coherent set of information that addresses all aspects of in-orbit calibration. Finally, we present the perspectives that the high level of agility of PLEIADES offers for the improvement of its calibration and a better characterization of the calibration sites.

The absolute radiometric calibration of the advanced very high resolution radiometer

Science.gov (United States)

Slater, P. N.; Teillet, P. M.; Ding, Y.

1988-01-01

An increasing number of remote sensing investigations require radiometrically calibrated imagery from NOAA Advanced Very High Resolution Radiation (AVHRR) sensors. Although a prelaunch calibration is done for these sensors, there is no capability for monitoring any changes in the in-flight absolute calibration for the visible and near infrared spectral channels. Hence, the possibility of using the reflectance-based method developed at White Sands for in-orbit calibration of LANDSAT Thematic Mapper (TM) and SPOT Haute Resolution Visible (HVR) data to calibrate the AVHRR sensor was investigated. Three diffrent approaches were considered: Method 1 - ground and atmospheric measurements and reference to another calibrated satellite sensor; Method 2 - ground and atmospheric measurements with no reference to another sensor; and Method 3 - no ground and atmospheric measurements but reference to another satellite sensor. The purpose is to describe an investigation on the use of Method 2 to calibrate NOAA-9 AVHRR channels 1 and 2 with the help of ground and atmospheric measurements at Rogers (dry) Lake, Edwards Air Force Base (EAFB) in the Mojave desert of California.

The absolute radiometric calibration of the advanced very high resolution radiometer

Science.gov (United States)

Slater, P. N.; Teillet, P. M.; Ding, Y.

1988-10-01

An increasing number of remote sensing investigations require radiometrically calibrated imagery from NOAA Advanced Very High Resolution Radiation (AVHRR) sensors. Although a prelaunch calibration is done for these sensors, there is no capability for monitoring any changes in the in-flight absolute calibration for the visible and near infrared spectral channels. Hence, the possibility of using the reflectance-based method developed at White Sands for in-orbit calibration of LANDSAT Thematic Mapper (TM) and SPOT Haute Resolution Visible (HVR) data to calibrate the AVHRR sensor was investigated. Three diffrent approaches were considered: Method 1 - ground and atmospheric measurements and reference to another calibrated satellite sensor; Method 2 - ground and atmospheric measurements with no reference to another sensor; and Method 3 - no ground and atmospheric measurements but reference to another satellite sensor. The purpose is to describe an investigation on the use of Method 2 to calibrate NOAA-9 AVHRR channels 1 and 2 with the help of ground and atmospheric measurements at Rogers (dry) Lake, Edwards Air Force Base (EAFB) in the Mojave desert of California.

Direct megavoltage photon calibration service in Australia

International Nuclear Information System (INIS)

Butler, D.J.; Ramanthan, G.; Oliver, C.; Cole, A.; Harty, P.D.; Wright, T.; Webb, D.V.; Lye, J.; Followill, D.S.

2014-01-01

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) maintains the Australian primary standard of absorbed dose. Until recently, the standard was used to calibrate ionisation chambers only in 60 Co gamma rays. These chambers are then used by radiotherapy clinics to determine linac output, using a correction factor (k Q ) to take into account the different spectra of 60 Co and the linac. Over the period 2010–2013, ARPANSA adapted the primary standard to work in megavoltage linac beams, and has developed a calibration service at three photon beams (6, 10 and 18 MV) from an Elekta Synergy linac. We describe the details of the new calibration service, the method validation and the use of the new calibration factors with the International Atomic Energy Agency’s TRS-398 dosimetry Code of Practice. The expected changes in absorbed dose measurements in the clinic when shifting from 60 Co to the direct calibration are determined. For a Farmer chamber (model 2571), the measured chamber calibration coefficient is expected to be reduced by 0.4, 1.0 and 1.1 % respectively for these three beams when compared to the factor derived from 60 Co. These results are in overall agreement with international absorbed dose standards and calculations by Muir and Rogers in 2010 of k Q factors using Monte Carlo techniques. The reasons for and against moving to the new service are discussed in the light of the requirements of clinical dosimetry.

Metrological reliability of the calibration procedure in terms of air kerma using the ionization chamber NE2575

International Nuclear Information System (INIS)

Guimaraes, Margarete Cristina; Silva, Teogenes Augusto da; Rosado, Paulo H.G.

2016-01-01

Metrology laboratories are expected to provide X radiation beams that were established by international standardization organizations to perform calibration and testing of dosimeters. Reliable and traceable standard dosimeters should be used in the calibration procedure. The aim of this work was to study the reliability of the NE 2575 ionization chamber used as standard dosimeter for the air kerma calibration procedure adopted in the CDTN Calibration Laboratory. (author)

Calibration setting numbers for dose calibrators for the PET isotopes "5"2Mn, "6"4Cu, "7"6Br, "8"6Y, "8"9Zr, "1"2"4I

International Nuclear Information System (INIS)

Wooten, A. Lake; Lewis, Benjamin C.; Szatkowski, Daniel J.; Sultan, Deborah H.; Abdin, Kinda I.; Voller, Thomas F.; Liu, Yongjian; Lapi, Suzanne E.

2016-01-01

For PET radionuclides, the radioactivity of a sample can be conveniently measured by a dose calibrator. These devices depend on a “calibration setting number”, but many recommended settings from manuals were interpolated based on standard sources of other radionuclide(s). We conducted HPGe gamma-ray spectroscopy, resulting in a reference for determining settings in two types of vessels containing one of several PET radionuclides. Our results reiterate the notion that in-house, experimental calibrations are recommended for different radionuclides and vessels. - Highlights: • Dose calibrators measure radioactivity by ionization of gas from emitted radiation. • Accuracy of dose calibrators depends on “calibration setting numbers” for isotopes. • Many manufacturer settings are interpolated from emissions of other radionuclides. • As a high-precision reference, HPGe gamma-ray spectroscopy was conducted. • New calibrations were found for PET isotopes "5"2Mn, "6"4Cu, "7"6Br, "8"6Y, "8"9Zr, and "1"2"4I.

Sistemas de serviços de saúde: principais tipologias e suas relações com os sistema de saúde brasileiro

OpenAIRE

José Patrício Bispo Júnior; Kelly Leite Maia de Messias

2005-01-01

O presente artigo discute as principais características dos Sistemas de Serviços de Saúde e relaciona o Sistema de Saúde Brasileiro com os três principais tipos de Sistemas de Serviços de Saúde. Conceitua e diferencia Sistema de Saúde de Sistemas de Serviços de Saúde. Apresenta a conformação, objetivos, componentes, características e funções dos Sistemas de Serviços de Saúde. Apresenta e discute os três principais tipos de Sistemas de Serviços de Saúde: Sistema de Saúde de Dominância de Me...

Investigation of ground-based microwave radiometer calibration techniques at 530 hPa

Directory of Open Access Journals (Sweden)

G. Maschwitz

2013-10-01

Full Text Available Ground-based microwave radiometers (MWR are becoming more and more common for remotely sensing the atmospheric temperature and humidity profile as well as path-integrated cloud liquid water content. The calibration accuracy of the state-of-the-art MWR HATPRO-G2 (Humidity And Temperature Profiler – Generation 2 was investigated during the second phase of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II in northern Chile (5320 m above mean sea level, 530 hPa conducted by the Atmospheric Radiation Measurement (ARM program conducted between August and October 2009. This study assesses the quality of the two frequently used liquid nitrogen and tipping curve calibrations by performing a detailed error propagation study, which exploits the unique atmospheric conditions of RHUBC-II. Both methods are known to have open issues concerning systematic offsets and calibration repeatability. For the tipping curve calibration an uncertainty of ±0.1 to ±0.2 K (K-band and ±0.6 to ±0.7 K (V-band is found. The uncertainty in the tipping curve calibration is mainly due to atmospheric inhomogeneities and the assumed air mass correction for the Earth curvature. For the liquid nitrogen calibration the estimated uncertainty of ±0.3 to ±1.6 K is dominated by the uncertainty of the reflectivity of the liquid nitrogen target. A direct comparison between the two calibration techniques shows that for six of the nine channels that can be calibrated with both methods, they agree within the assessed uncertainties. For the other three channels the unexplained discrepancy is below 0.5 K. Systematic offsets, which may cause the disagreement of both methods within their estimated uncertainties, are discussed.

Technical Note: Calibration and validation of geophysical observation models

NARCIS (Netherlands)

Salama, M.S.; van der Velde, R.; van der Woerd, H.J.; Kromkamp, J.C.; Philippart, C.J.M.; Joseph, A.T.; O'Neill, P.E.; Lang, R.H.; Gish, T.; Werdell, P.J.; Su, Z.

2012-01-01

We present a method to calibrate and validate observational models that interrelate remotely sensed energy fluxes to geophysical variables of land and water surfaces. Coincident sets of remote sensing observation of visible and microwave radiations and geophysical data are assembled and subdivided

Determination of calibration factors for whole body counting of members of public

International Nuclear Information System (INIS)

Vijayagopal, P.; Joyeeta, M.; Garg, S.P.; Vidhani, J.M.; Pendharkar, K.A.

2005-01-01

A Mobile Radiological Laboratory (MRL) was recently developed by Internal Dosimetry Division in BARC. In the event of an accident involving release of radioactive substances into the environment, there will be a need to measure both the external and the internal exposure of the population. MRL has been equipped with a variety of radiation detectors, radiation survey meters and a whole body monitor for this purpose. For whole body monitoring of members of public, detector systems are required to be calibrated with the age dependent phantoms of appropriate size for both male and female subjects. In this paper we present the results of the calibration studies carried out with shielded chair whole body counter of MRL using five different age dependent male phantoms representing the age groups of 1,5,10 and 15 year old children and 20 year old adult. Calibration work has been carried out using standard sources of 137 Cs, 133 Ba and 60 Co. (author)

Secondary calibration laboratory for dosimetry in levels of therapy at the University of Santiago

International Nuclear Information System (INIS)

Gomez Rodriguez, F.; Gonzalez Castano, D. M.; Pazos Alvarez, A.

2011-01-01

A basic inherent benefits provided by the existence of a traceability chain radiation in any application, add the legal requirement for hospitals as pointed to by the RO. 1566/1998, which sets quality standards in radiotherapy. The decree attributed to hospital specialists radio physics in article 10 the responsibility for determining the acceptance and initial reference state of radiation generating equipment for therapeutic purposes, and the establishment and implementation of quality control programs associated and technical and physical aspects of radiation dosimetry. Different international organizations such as ICRU and IAEA recommendations on maintaining the accuracy of the dose delivered to patients in general, should be placed at least 5% considering the whole chain irradiation. In order to achieve this purpose it is necessary to establish programs of quality control and calibration dosimetric regular basis. The protocol of the IAEA TRS398 recommended dose calibration in water because it is a quantity of interest closest to clinical use and allows a relative uncertainty in the calibration environment reduced to 1%.. (Author)

Calibration and Performance Testing of Sodium Iodide, NaI (Tl)

African Journals Online (AJOL)

Administrator

performed by the well-established method of ... gamma-rays emitted from radionuclides in a ... 1 Radiation Protection Institute, Ghana Atomic Energy Commission, P. O. Box ... validation of the calibration showed that there were no significance ...

Spectroscopic and bolometric measurements of radiation loss in DIVA

International Nuclear Information System (INIS)

Shiho, Makoto; Odajima, Kazuo; Sugie, Tatsuo; Maeda, Hikosuke; Kasai, Satoshi

1977-11-01

Radiation loss due to low- and high-z impurities in DIVA (JFT-2a) was measured by means of a calibrated 3m grazing incidence vacuum monochromater and a calibrated pyroelectric detector. The following results were obtained: 1) Radiation loss power due to low-z impurities becomes insignificant by using clean surfaces for the vacuum wall. 2) Radiation loss power due to pseudo continuum from high-z impurities has influence on the energy balance of the confined plasma. 3) The divertor reduces the radiation loss by a factor of about 3. (auth.)

Bench calibration of INDUS-2 beam position indicators

International Nuclear Information System (INIS)

Tyagi, Y.; Banerji, Anil; Kotaiah, S.

2005-01-01

A third generation synchrotron radiation source of energy 2.5 GeV named INDUS-2 at Centre for Advanced Technology (C.A.T), Indore (M.P) is in the advanced stage of construction. Accurate determination and correction of beam closed orbit in INDUS-2 machine within 100 of microns is a very desirable goal. Bench based calibration of Beam Position Indicators (BPI) play a very important and useful role during initial commissioning of electron machines. To precisely measure transverse position of electron beam in the Indus-2 storage ring, 56 Beam Position Indicators (BPI) will be installed in INDUS-2 machine. Out of 56 Beam Position Indicators 40 are of individual type whereas 16 are integrated with dipole vacuum chamber. The Beam Position Indicators are required to be calibrated before they can be installed. The calibration is done to determine electrical offset with respect to defined mechanical centre, to determine displacement sensitivities as well as non linearity's of BPI. Ideally when beam passes through the geometrical center of BPI's, all electrodes should have same signal strength. However due to different capacitance of electrodes and offset and drift in electronics, the electrical centre (mechanical x, y where all electrodes shows same signal strength) differs from mechanical centre of BPI. A fully automatic calibration system has been developed to carry out the calibration of Beam Position Indicators. A calibration software has been developed which has necessary utilities to process and display calibration data and results. This paper describes the calibration results of Indus-2 BPM. (author)

Sistemas de tiempo real y sistemas distribuidos de tiempo real

OpenAIRE

Pesado, Patricia Mabel; Ramón, Hugo Dionisio; Boracchia, Marcos; Pasini, Ariel C.; De Vito, María Cecilia; Osella Massa, Germán Leandro; Estrebou, César Armando

2006-01-01

El proyecto de investigación y desarrollo en Sistemas de Software Distribuido, abarca aspectos que van desde los fundamentos del desarrollo (Técnicas de Ingeniería de Requerimientos, Metodologías de Gestión y Desarrollo de Proyectos, Técnicas de Planificación, Métricas, Normas de Calidad, Web-Systems) hasta la concepción de aplicaciones específicas orientadas a los procesos industriales (Sistemas de Planeamiento de Producción, Control Industrial en tiempo real), procesos de E-government (Voto...

Portable microcomputer controlled radiation counter

International Nuclear Information System (INIS)

Mason, E.W.; Weber, J.M.

1984-01-01

A portable microcomputer controlled counter for use as a radiation counter is described. The counter uses digital processing of input pulses from a radiation detector. The number of counts received by the microcomputer per unit time is used to calculate a value for display using a calibration factor obtained during physical calibration of the instrument with a radiation source or with a pulse generator. The keyboard is used to enter calibration points. The number of calibration points which may be entered depends on the degree of accuracy desired by the user. The high voltage generator which drives the detector is triggered by pulses from the microcomputer in relation to the count rate. After processing the count, the resulting count rate or dose rate is displayed on the liquid crystal display. The counter is autoranging in which the decimal point is shifted as necessary by the microcomputer. The units displayed are determined by the user by means of a multiposition switch. Low battery and an overrange condition are displayed. An interface is provided via a connector to allow parallel transmission of data to peripheral devices. Low battery power consumption is featured. The counter is capable of providing more accurate readings than currently available counters

A convenient calibrator for tritium survey meters

International Nuclear Information System (INIS)

Cutler, J.M.; Janmohamed, S.R.; Surette, R.A.; Wood, M.J.

1993-06-01

Staff in Ontario Hydro's CANDU nuclear power stations were having difficulty calibrating their tritium-in-air survey meters. Chalk River Laboratories suggested using a standard silica gel collector loaded with tritiated water vapour as a radiation source. The collector is a polyethylene tube with a length of rubber tubing attached to each end. The plastic tube is filled with dry silica gel, and cotton wool is stuffed into each end to retain the gel. To load the source with tritiated vapour, a bubbler containing tritiated water is connected to the collector until the gel is completely pink. The end tubes of the source are then connected to each other to seal the source. To use the source, the rubber tubes are connected to the intake and exhaust fittings of the survey meter to be calibrated. No tritium vapour is released during loading or calibration. This source not only verifies that the ion chamber and electrometer are working, but also checks whether the air sample is reaching the detector. It is more direct and credible than a gamma source, and is inexpensive and convenient to construct and calibrate at the power station. 5 figs

SU-E-T-749: Thorough Calibration of MOSFET Dosimeters

International Nuclear Information System (INIS)

Plenkovich, D; Thomas, J

2015-01-01

Purpose: To improve the accuracy of the MOSFET calibration procedure by performing the measurement several times and calculating the average value of the calibration factor for various photon and electron energies. Methods: The output of three photon and six electron beams of Varian Trilogy linear accelerator SN 5878 was calibrated. Five reinforced standard sensitivity MOSFET dosimeters were placed in the calibration jig and connected to the Reader Module. As the backscatter material was used 7 cm of Virtual Water. The MOSFET dosimeters were covered with 1.5 cm thick bolus for the regular and SRS 6 MV beams, 3 cm bolus for 15 MV beam, 1.5 cm bolus for 6 MeV electron beam, and 2 cm bolus for the electron energies of 9, 12, 15, 18, and 22 MeV. The dosimeters were exposed to 100 MU, and the calibration factor was determined using the mobileMOSFET software. To improve the accuracy of calibration, this procedure was repeated ten times and the calibration factors were averaged. Results: As the number of calibrations was increasing the variability of calibration factors of different dosimeters was decreasing. After ten calibrations, the calibration factors for all five dosimeters were within 1% of one another for all energies, except 6 MV SRS photons and 6 MeV electrons, for which the variability was 2%. Conclusions: The described process results in calibration factors which are almost independent of modality or energy. Once calibrated, the dosimeters may be used for in-vivo dosimetry or for daily verification of the beam output. Measurement of the radiation dose under bolus and scatter to the eye are examples of frequent use of calibrated MOSFET dosimeters. The calibration factor determined for full build-up is used under these circumstances. To the best of our knowledge, such thorough procedure for calibrating MOSFET dosimeters has not been reported previously. Best Medical Canada provided MOSFET dosimeters for this project

Sistema de radiació solar via USB

OpenAIRE

Villanueva López, José Vicente

2008-01-01

L’objectiu d’aquest projecte és implementar un sistema de mesura de la irradiació solar a la Terra basat en una placa solar fotovoltaica. S’ha dissenyat i construït un sistema de mesura de la radiació solar que pot ser útil per aquells que instal·len sistemes fotovoltaics, que pot permetre l’estudi pràctic de les variables energètiques i econòmiques que ens poden indicar quin sistema és mes rentable construir, si un sistema de pannell solar fix, un sistema de pannell solar o...

A comparison of different neutron probes calibration method for the soil surface and their radiation effect on the users

Energy Technology Data Exchange (ETDEWEB)

Arslan, A; Razzouk, A K; Al-Ain, F [Atomic Energy commission , Damascus (Syrian Arab Republic). Dept of Radiation Agriculture

1996-08-01

In situ calibration curves were installed for the soil surface using different models of depth neutron probes and different adaptors. depth beutron probe readings increased with increasing the number of teflon plastic blocks deposited on the soil surface. The intercept of the straight line regression analysis decreased with increasing of teflon plastics blocks deposited on the soil surface in all sites. The least exposure was with depth probe with surface reflectors. This study proves the possibility of measuring the moisture content of the soil surface by using a depth probe with a block laid on the surface, without a danger of receiving the thresgold of radiation dose. (author). 10 Refs., 2 Figs., 8 Tabs.

AVIRIS Inflight Calibration Experiments, Analysis, and Results in 2000

Science.gov (United States)

Green, Robert O.; Pavri, Betina

2001-01-01

The NASA Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) measures spectra from 370 to 2500 nm with nominally 10-nm sampling and resolution. The spectra are acquired as images with an 11 km width and up to 800 km length from the ER-2 platform or 2.1 km width and 160 km length from the Twin Otter platform. AVIRIS measurements are used for a range of Earth science research and application objectives. The molecular absorption and particle scattering properties expressed in the calibrated AVIRIS measurements are used. For both science research and application objectives, calibration of the AVIRIS spectra is required to produce useful results. Each year prior to the flight season AVIRIS is calibrated in the laboratory. However, the temperature, pressure, vibration, and observational geometry, as well as mechanical, electrical, and operational interfaces of the laboratory are different than the environment on board the airborne platform. To validate the calibration of AVIRIS in the flight environment, an inflight calibration experiment is orchestrated at the beginning of each flight season. In most years additional inflight calibration experiments occur towards the middle and end of the flight season as well. For an inflight calibration experiment, AVIRIS acquires airborne data over a designated calibration target. In concert with the airborne data acquisition, surface and atmospheric properties at the calibration target are measured in situ. These in situ measurements are used to constrain a radiative transfer code and predict the radiance incident at the AVIRIS instrument from the calibration target. This prediction is compared with the AVIRIS-measured radiance to validate the calibration of AVIRIS in the flight environment. Additional properties (such as the AVIRIS inflight measurement precision) are determined as well. This paper presents measurements, analyses, and results from the inflight calibration experiment held on the dry lake bed surface of Rogers Dry

DOS SISTEMAS AMBIENTAIS AO SISTEMA FLUVIAL – UMA REVISÃO DE CONCEITOS

Directory of Open Access Journals (Sweden)

Jonas Otaviano Praça de Souza

2013-10-01

Full Text Available Tentando consolidar as noções de totalidade, a geografia física passa a utilizar a noção de sistemas dinâmicos, não lineares e de comportamento caótico. Deste modo, a abordagem sistêmica/complexa apresenta-se como meio de compreensão do mundo natural, assim possibilitando a previsão de mudanças, avaliação dos sistemas ambientais, distúrbios e limiares do sistema. Nota-se, assim, a importância dos estudos processuais para o gerenciamento de recursos hídricos, tornando imprescindíveis estudos sistêmicos que analisem os diversos elementos importantes para a análise dos recursos hídricos, dentre eles as questões processuais. Deste modo, a necessidade de se trabalhar o gerenciamento integrado de recursos hídricos, enquadrado na perspectiva sistêmica, solidificou a bacia hidrográfica e/ou bacia de drenagem como recorte espacial sistêmico. Delimitada a área pode-se compreender a bacia hidrográfica como um Sistema Fluvial, conceituado por Schumm (1977, que é analisado a partir da zona fonte de sedimentos, da rede de transporte e dos sítios de deposição. Esses elementos não são espacialmente excludentes, interagindo entre si, além de apresentar escalas diferenciadas. Para o estudo do sistema fluvial é necessário levar em consideração quatro conceitos: uniformidade dos processos, limiares de mudança, evolução da paisagem e respostas complexas.

Sistema Automatizado de Emailing Marketing

OpenAIRE

Martínez López, Javier

2010-01-01

Projecte final de carrera realitzat en col.laboració amb E-xpertel S.A El presente proyecto describe el diseño e implementación de un sistema de automatización de campañas de marketing a través de email hacia clientes y/o clientes potenciales. Este sistema tiene como objetivos principales adquirir nuevos clientes y conseguir la delización de los mismos. El sistema se complementa con una plataforma CRM (Customer Relationship Management) para el mantenimiento de datos de empresa...

Regulatory requirements and quality assurance of radiation monitoring instruments

International Nuclear Information System (INIS)

Narasimharao, K.L.; Sharma, Ranjit

2005-01-01

The successful utilisation of radiation sources in the fields of medicine and industry requires the accurate measurement of activity, exposure rate and dose. Many varieties of instruments are in use for measurement of these parameters and new ones are being developed. The criteria for the design of the radiation monitoring instrument include the type and intensity of the radiation, purpose of measurement and ruggedness of the instrument. Quality and reliability of radiation monitoring instruments ensure that individuals are adequately protected. Accuracy, response time and ruggedness are required to be as per the approved/ prescribed guidelines. Regulatory authorities outline the design and performance criteria for radiation monitoring instruments and prescribe the recommendations of international agencies such as IAEA, ICRU and ISO for radiological measurement assurance programme. National Standards Laboratories all over the world prescribe procedures for calibration of various radiation monitoring instruments. The instruments should be calibrated as per these guidelines and should be traceable to national standards. The calibration traceable to national/ international standards and documentation as well as limits stipulated by the competent authority ensures the expected performance of the instrument. (author)

Experimental verification of self-calibration radiometer based on spontaneous parametric downconversion

Science.gov (United States)

Gao, Dongyang; Zheng, Xiaobing; Li, Jianjun; Hu, Youbo; Xia, Maopeng; Salam, Abdul; Zhang, Peng

2018-03-01

Based on spontaneous parametric downconversion process, we propose a novel self-calibration radiometer scheme which can self-calibrate the degradation of its own response and ultimately monitor the fluctuation of a target radiation. Monitor results were independent of its degradation and not linked to the primary standard detector scale. The principle and feasibility of the proposed scheme were verified by observing bromine-tungsten lamp. A relative standard deviation of 0.39 % was obtained for stable bromine-tungsten lamp. Results show that the proposed scheme is advanced of its principle. The proposed scheme could make a significant breakthrough in the self-calibration issue on the space platform.

Ultra-portable field transfer radiometer for vicarious calibration of earth imaging sensors

Science.gov (United States)

Thome, Kurtis; Wenny, Brian; Anderson, Nikolaus; McCorkel, Joel; Czapla-Myers, Jeffrey; Biggar, Stuart

2018-06-01

A small portable transfer radiometer has been developed as part of an effort to ensure the quality of upwelling radiance from test sites used for vicarious calibration in the solar reflective. The test sites are used to predict top-of-atmosphere reflectance relying on ground-based measurements of the atmosphere and surface. The portable transfer radiometer is designed for one-person operation for on-site field calibration of instrumentation used to determine ground-leaving radiance. The current work describes the detector- and source-based radiometric calibration of the transfer radiometer highlighting the expected accuracy and SI-traceability. The results indicate differences between the detector-based and source-based results greater than the combined uncertainties of the approaches. Results from recent field deployments of the transfer radiometer using a solar radiation based calibration agree with the source-based laboratory calibration within the combined uncertainties of the methods. The detector-based results show a significant difference to the solar-based calibration. The source-based calibration is used as the basis for a radiance-based calibration of the Landsat-8 Operational Land Imager that agrees with the OLI calibration to within the uncertainties of the methods.

Radioactive contamination in monitors received for calibration

International Nuclear Information System (INIS)

Dias, Paulo S.; Santos, Gilvan C. dos; Brunelo, Maria Antonieta G.; Paula, Tiago C. de; Pires, Marina A.; Borges, Jose C.

2013-01-01

The Calibration Laboratory - LABCAL, from the Research Center for Metrology and Testing - METROBRAS, MRA Comercio de Instrumentos Eletronicos Ltda., began activities in October 2008 and, in August 2009, decided to establish a procedure for monitoring tests, external and internal, of all packages received from customers, containing instruments for calibration. The aim was to investigate possible contamination radioactive on these instruments. On July 2011, this procedure was extended to packagings of personal thermoluminescent dosemeters - TLD, received by the newly created Laboratory Laboratorio de Dosimetria Pessoal - LDP . In the monitoring procedure were used monitors with external probe, type pancake, MRA brand, models GP - 500 and MIR 7028. During the 37 months in which this investigation was conducted, were detected 42 cases of radioactive contamination, with the following characteristics: 1) just one case was personal dosimeter, TLD type; 2) just one case was not from a packing from nuclear medicine service - was from a mining company; 3) contamination occurred on packs and instruments, located and/or widespread; 4) contamination values ranged from slightly above the level of background radiation to about a thousand fold. Although METROBRAS has facilities for decontamination, in most cases, especially those of higher contamination, the procedure followed was to store the contaminated material in a room used for storage of radioactive sources. Periodically, each package and/or instrument was monitored, being released when the radiation level matched the background radiation. Every contamination detected, the client and/or owner of the instrument was informed. The Brazilian National Energy Commission - CNEN, was informed, during your public consultation for reviewing the standard for nuclear medicine services, held in mid-2012, having received from METROBRAS the statistical data available at the time. The high frequency of contamination detected and the high

Standardization of reference radiation field of beta for 85Kr using extrapolation chamber

International Nuclear Information System (INIS)

Nazaroh; Fendinugroho

2013-01-01

Standardization of reference radiation field of beta for 85 Kr in PTKMR-BATAN Laboratory has been performed at the SDD's 30 cm by using extrapolation chamber detector, coupled with Uni dose electrometer. The result was : (8.98±3 %) mGy/h, at 95 % confidence level. The aim of standardization of reference radiation field is to support radiation protection and safety program, provided by the International Atomic Energy Agency to its Member States, included BATAN-Indonesia, especially, PTKMR. The aim of radiation protection program and safety program is to promote an internationally harmonized approach for radiation measurement in protection level, besides for calibration of radiation measuring instrument, which users spread across Indonesia, with the number of about 795 firms in the year of 2012. These benefits can be felt by workers, communities and the environment, because by calibration, measurement survey meter, pocket dosimeter and TLD to be more accurate so that the radiation dose received by radiation workers is accurate and can be ascertained in a specified period, not to exceed a predetermined NBD by BAPETEN. The aim of this calibration is appropriate with the primary objective of calibration on IAEA/TRS16:2000. (author)

Test of an albedo neutron dosimetry system: TLD calibration and readout procedure, neutron calibration, dosimetry properties, routine application

International Nuclear Information System (INIS)

Piesch, E.; Burgkhardt, B.

1988-03-01

The two-component albedo dosemeter in use consists of an universal boron-loaded plastic encapsulation, the beta and albedo neutron windows of which are adopted to the corresponding TLD system of the manufacturers Alnor, Harshaw, Panasonic and Vinten. Beside the TLD detectors the capsule may contain also track etch detectors. Within a BMU project the system was investigated by four governmental measurement services in the FRG with respect to its qualification for personnel monitoring with emphasis in the readout and calibration procedures for the TLD system, the evaluation technique for the estimation of the photon and neutron dose equivalent in routine monitoring and the calibration of the personnel dosemeter in stray neutron fields. The test has shown the readiness of the system to act in the application areas of nuclear power reactors and linacs behind heavy shieldings, in the fuel element cycle, use of fissile materials, criticality, use of radionuclide sources, high energy particle accelerators. The uncertainty due to energy dependence was found to be within a factor of 2 for a single application area. In the case of irradiations from the front half space the dose equivalent H'(10) is indicated sufficiently independent of the direction of the radiation incidence. After completion of the test the albedo dosemeter became the official neutron personnel dosemeter in the FRG. It allows the separate estimation of the dose equivalent of hard beta radiation, photon radiation and neutrons. (orig./HP) [de

Synchrotron Radiation Facility

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: Studies the effects of UV radiation and X rays on solids, and calibrates X-ray optics, detectors, and instruments.DESCRIPTION: Research focuses on applying...

Intercomparison of the air kerma and absorbed dose to water therapy calibrations provided by NRPA and CPRH SSDLs

International Nuclear Information System (INIS)

Morales, J.A.; Campa, R.; Bjerke, H.; Jensen, H.

2001-01-01

The primary goal of any calibration laboratory is to routinely provide calibration services of the highest accuracy. To this end, the laboratory should be equipped with measuring standards of the highest metrological quality traceable to the international measuring system, should establish the appropriate calibration conditions and implement good measuring and working practices. In the case of the Secondary Standard Dosimetry Laboratory (SSDL) members of the IAEA/WHO Network of SSDLs, a great deal of the service quality relies on the appropriate laboratory design and implementation of the recommended calibration practices. Different approaches have been used by SSDLs to guarantee the traceability of the reference standard to the international measurement system. These include calibration of their standards at the IAEA Dosimetry Laboratory, direct calibration at a primary standards laboratory or at a national calibration laboratory. The stability of reference and working standards is usually checked by means of radioactive check source measurements. The most comprehensive way that a laboratory could test its overall measurement competence is by taking part in comparisons with other laboratories of the same or higher metrological level. Regular efforts have been done at the regional scale by organizing such intercomparison exercises where the evaluation of the accuracy of secondary standards or the validation of new calibration methods has been the main objectives. Perhaps, the most important contribution to the assessment of SSDLs quality has been the periodical external measurement audit provided by the IAEA during the last years. Mos of these efforts have, however, only been focused on in-air and recently in-water calibration at the 60 Co radiation quality. An intercomparison of the therapy calibration services available at the SSDLs of the Norwegian Radiation Protection Authority (NRPA) and of the Center for Radiation Protection and Hygiene (CPHR) was organized

Reference neutron radiations. Part 1: Characteristics and methods of production

International Nuclear Information System (INIS)

2001-01-01

ISO 8529 consists of the following parts, under the general title Reference neutron radiations: Part 1: Characteristics and methods of production; Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field; Part 3: Calibration of area and personal dosimeters and determination of response as a function of energy and angle of incidence. This Part 1. of ISO 8529 specifies the reference neutron radiations, in the energy range from thermal up to 20 MeV, for calibrating neutron-measuring devices used for radiation protection purposes and for determining their response as a function of neutron energy. Reference radiations are given for neutron fluence rates of up to 1x10 9 m 2 s-1 , corresponding, at a neutron energy of 1 MeV, to dose-equivalent rates of up to 100 mSv h -1 . This part of ISO 8529 is concerned only with the methods of producing and characterizing the neutron reference radiations. The procedures for applying these radiations for calibrations are described in ISO 8529-2 and ISO 8529-3. The reference radiations specified are the following: neutrons from radionuclide sources, including neutrons from sources in a moderator; neutrons produced by nuclear reactions with charged particles from accelerators; neutrons from reactors. In view of the methods of production and use of them, these reference radiations are divided, for the purposes of this part of ISO 8529, into the following two separate sections. In clause 4, radionuclide neutron sources with wide spectra are specified for the calibration of neutron measuring devices. These sources should be used by laboratories engaged in the routine calibration of neutron-measuring devices, the particular design of which has already been type tested. In clause 5, accelerator-produced monoenergetic neutrons and reactor-produced neutrons with wide or quasi monoenergetic spectra are specified for determining the response of neutron-measuring devices

CP-50 calibration well facility: radiological safety assessment document

International Nuclear Information System (INIS)

Orcutt, J.A.; Hill, R.L.

1984-03-01

Design features, systems controls, and procedures used in the opeation of the calibration well facility are presented. Site and facility characteristics, as well as routine and nonroutine operations are discussed. Hypothetical incidents and accidents, source control systems, and radiation monitoring considerations are described. 8 references, 35 figures

Practical reference - radiation standards in Canada

International Nuclear Information System (INIS)

1983-07-01

In developing a policy that will require licensees to calibrate their radiation dose measuring devices and trace such calibrations to approved reference standards, the AECB has consulted recognized experts. This document presents the experts' reports and recommendations which will be considered in finalizing the policy

Establishment of standard low energy x-ray, radioprotection levels, for calibration of instruments

International Nuclear Information System (INIS)

Oliveira, Eliane Carmo

1995-01-01

Seven standard low energy X-rays fields were established, radioprotection level, at the Calibration Laboratory of IPEN. Five of the standard calibration qualities used at the National Physical Laboratory, England, with energies between 16 and 38 keV, and two recommended by the International Standard Organization, with energies of 33 and 48 keV, were reproduced. The calibration conditions, radiotherapy level, from 14 to 21 keV, were also verified. Different portable radiation monitors as ionization chambers and Geiger-Mueller detectors were studied in relation to their energy dependence. (author)

Estimation of uncertainty in TLD calibration

International Nuclear Information System (INIS)

Hasabelrasoul, H. A.

2013-07-01

In this study thermoluminescence dosimeter TLD was use of individual control devices to make sure the quality assurance and quality control in individual monitoring. The uncertainty measured in reader calibration coefficients for tow reader and uncertainty in radiation dose after irradiate in SSDL laboratory. Fifty sample was selected for the study was placed in the oven at a temperature of 400 for an hour to get zero or background and took zero count by or background and took zero count by reader (1) and reader (2) and then irradiate in SSDL by cesium-137 at a dose of 5 mGy and laid back in the oven at degrees 100 and degrees 10 minutes, to 10 chips for calibration and readout count by reader one and reader two. The RCF was found for each reader above 1.47 and 1.11, respectively, and found the uncertainty RCF was found for each reader above 1.47 and 1.11, respectively, and found the uncertainly RCF 0.430629 and 0.431973. Radiation dose was measured for fifty samples irradiate to dose of 5 mGy and read the count by reader 1 and reader 2 the uncertainty was found for each reader 0.490446 and 0.587602.(Author)

Study of the behavior of radiation detectors for mammography in standard beams using a clinical system; Estudo do comportamento de detectores de radiacao para mamografia em feixes padroes utilizando um sistema clinico

Energy Technology Data Exchange (ETDEWEB)

Barreira, Jacqueline Sales

2014-07-01

A mammogram is the x-ray of the breast that allows early detection of cancer, by being able to show lesions in very small early stage. But to get an early and reliable diagnosis is necessary that the mammography unit is calibrated and working properly, otherwise there may be a loss in image produced, may lead to a false diagnosis, and possible harm to the patient. So it is important to control these devices, especially in relation to the radiation produced by them. In this project, we propose a study of the behavior of ionization chambers for mammography calibrated beam patterns in a clinical system (Philips-VMI mammography, Graph Mammo AF, which operates a range of 20 to 35 kV) from Instruments Calibration Laboratory at IPEN-CNEN/SP, with the aim of determining parameters correction approaching conditions calibration conditions for clinical use. Measurements of the parameters of the beams set in mammography using simulators acrylic specially developed for these measurements were performed in order to establish a new protocol for calibration of the ionization chambers in a clinical system rather than the industrial system, or as a complement to this. (author)

Importancia del manual de los sistemas contables en el sistema de control interno.

Directory of Open Access Journals (Sweden)

Nicolás Valdés Rodríguez

2007-01-01

Full Text Available La dirección administrativa del país en los últimos 3 años ha insistido en la necesidad de profundizar en los mecanismos de control económico –financiero de las entidades, el presente trabajo va dirigido a contribuir en alguna medida a lograr ese propósito. El sistema contable de una Entidad forma parte indisoluble del Sistema de Control Interno de la misma, por la vinculación tan estrecha que existe entre los mismos. El objetivo fundamental del trabajo ”Importancia del Manual de los Sistemas Contables en el Sistema de Control Interno”, es destacar la utilidad práctica, técnica y organizativa que tiene el Manual para elevar la eficiencia del trabajo contable de las Entidades y su repercusión positiva en la eficiencia el sistema de Control Interno establecido. Los beneficios que aporta el Manual radican en que crea una base normativa contable adecuada a las características de cada entidad. Como se sabe en las transformaciones económicas realizadas en el país, la existencia de dos monedas en el trabajo económico-contable de muchas entidades, la puntualización del objeto social y la cartera de productos y servicios han complejizado el trabajo contable, requiriendo una mayor adecuación a las características propias de cada entidad, lo cual se logra con la realización del Manual.

Calibration

International Nuclear Information System (INIS)

Greacen, E.L.; Correll, R.L.; Cunningham, R.B.; Johns, G.G.; Nicolls, K.D.

1981-01-01

Procedures common to different methods of calibration of neutron moisture meters are outlined and laboratory and field calibration methods compared. Gross errors which arise from faulty calibration techniques are described. The count rate can be affected by the dry bulk density of the soil, the volumetric content of constitutional hydrogen and other chemical components of the soil and soil solution. Calibration is further complicated by the fact that the neutron meter responds more strongly to the soil properties close to the detector and source. The differences in slope of calibration curves for different soils can be as much as 40%

On-line calibration of process instrumentation channels in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Hashemian, H.M.; Farmer, J.P. [Analysis and Measurement Services Corp., Knoxville, TN (United States)

1995-04-01

An on-line instrumentation monitoring system was developed and validated for use in nuclear power plants. This system continuously monitors the calibration status of instrument channels and determines whether or not they require manual calibrations. This is accomplished by comparing the output of each instrument channel to an estimate of the process it is monitoring. If the deviation of the instrument channel from the process estimate is greater than an allowable limit, then the instrument is said to be {open_quotes}out of calibration{close_quotes} and manual adjustments are made to correct the calibration. The success of the on-line monitoring system depends on the accuracy of the process estimation. The system described in this paper incorporates both simple intercomparison techniques as well as analytical approaches in the form of data-driven empirical modeling to estimate the process. On-line testing of the calibration of process instrumentation channels will reduce the number of manual calibrations currently performed, thereby reducing both costs to utilities and radiation exposure to plant personnel.

PTB’s radiometric scales for UV and VUV source calibration based on synchrotron radiation

Science.gov (United States)

Klein, Roman; Kroth, Simone; Paustian, Wolfgang; Richter, Mathias; Thornagel, Reiner

2018-06-01

The radiant intensity of synchrotron radiation can be accurately calculated with classical electrodynamics. This primary realization of the spectral radiant intensity has been used by PTB at several electron storage rings which have been optimized to be operated as primary source standards for the calibration of transfer sources in the spectral range of UV and VUV for almost 30 years. The transfer sources are compared to the primary source standard by means of suitable wavelength-dispersive transfer stations. The spectral range covered by deuterium lamps, which represent transfer sources that are easy to handle, is of particular relevance in practice. Here, we report on developments in the realization and preservation of the radiometric scales for spectral radiant intensity and spectral radiance in the wavelength region from 116 nm to 400 nm, based on a set of deuterium reference lamps, over the last few decades. An inside view and recommendations on the operation of the D2 lamps used for the realization of the radiometric scale are presented. The data has been recently compiled to illustrate the chronological behaviour at various wavelengths. Moreover, an overview of the internal and external validation measurements and intercomparisons is given.

An MLC calibration method using a detector array

International Nuclear Information System (INIS)

Simon, Thomas A.; Kahler, Darren; Simon, William E.; Fox, Christopher; Li, Jonathan; Palta, Jatinder; Liu, Chihray

2009-01-01

Purpose: The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. Methods: The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Corporation, Melbourne, FL). To calibrate the MLC bank, its backup jaw is positioned at the central axis and the opposing jaw is retracted to create a half-beam configuration. The position of the backup jaws field edge is then measured with the array to obtain what is termed the radiation defined reference line. The positions of the individual leaf ends relative to this reference line are then inferred by the detector response in the leaf end penumbra. Iteratively adjusting and remeasuring the leaf end positions to within specifications completes the calibration. Using the backup jaw as a reference for the leaf end positions is based on three assumptions: (1) The leading edge of an MLC leaf bank is parallel to its backup jaw's leading edge, (2) the backup jaw position is reproducible, and (3) the measured radiation field edge created by each leaf end is representative of that leaf's position. Data from an electronic portal imaging device (EPID) were used in a similar analysis to check the results obtained with the array. Results: The relative leaf end positions measured with the array differed from those measured with the EPID by an average of 0.11 ±0.09 mm per leaf. The maximum leaf positional change measured with the Profiler 2 over a 3 month period was 0.51 mm. A leaf positional accuracy of ±0.4 mm is easily attainable through the iterative calibration process. The method requires an average of 40 min to measure both leaf banks. Conclusions: This work demonstrates that the Profiler 2 is an effective tool for efficient and quantitative MLC quality assurance and calibration.

An MLC calibration method using a detector array

Energy Technology Data Exchange (ETDEWEB)

Simon, Thomas A.; Kahler, Darren; Simon, William E.; Fox, Christopher; Li, Jonathan; Palta, Jatinder; Liu, Chihray [Department of Nuclear and Radiological Engineering, University of Florida, 202 Nuclear Science Building, Gainesville, Florida 32611-8300 (United States); Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, Florida 32940 (United States) and Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, Florida 32940 (United States); Department of Radiation Oncology, Tulane University, 1415 Tulane Ave, HC65, New Orleans, Louisiana 70112 (United States); Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States)

2009-10-15

Purpose: The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. Methods: The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Corporation, Melbourne, FL). To calibrate the MLC bank, its backup jaw is positioned at the central axis and the opposing jaw is retracted to create a half-beam configuration. The position of the backup jaws field edge is then measured with the array to obtain what is termed the radiation defined reference line. The positions of the individual leaf ends relative to this reference line are then inferred by the detector response in the leaf end penumbra. Iteratively adjusting and remeasuring the leaf end positions to within specifications completes the calibration. Using the backup jaw as a reference for the leaf end positions is based on three assumptions: (1) The leading edge of an MLC leaf bank is parallel to its backup jaw's leading edge, (2) the backup jaw position is reproducible, and (3) the measured radiation field edge created by each leaf end is representative of that leaf's position. Data from an electronic portal imaging device (EPID) were used in a similar analysis to check the results obtained with the array. Results: The relative leaf end positions measured with the array differed from those measured with the EPID by an average of 0.11 {+-}0.09 mm per leaf. The maximum leaf positional change measured with the Profiler 2 over a 3 month period was 0.51 mm. A leaf positional accuracy of {+-}0.4 mm is easily attainable through the iterative calibration process. The method requires an average of 40 min to measure both leaf banks. Conclusions: This work demonstrates that the Profiler 2 is an effective tool for efficient and quantitative MLC quality assurance and calibration.

Calibration of the indicators of the product KERMa-AREA in radiodiagnostic equipment

International Nuclear Information System (INIS)

Ginjaume, M.; Jarvinen, H.; Turak, O.

2013-01-01

Currently the IAEA proposes two procedures for the calibration of the determination of the PKA systems integrated in the x-ray equipment. The traditional method is to measure air kerma at a certain distance from the focus through an ionization chamber reference and then the area of the field of radiation in that position. The alternative method is based on measuring directly the product kerma-area using equipment calibrated in this magnitude. In both cases the calibration procedure takes into account the position of the tube on the stretcher of the patient. The objective of this study was to compare the practical application of both calibration procedures as well as assess the accuracy of indication of the PKA in the consoles of the radiology equipment. (Author)

Sistema de inferencia difusa basado en relaciones Booleanas

Directory of Open Access Journals (Sweden)

Helbert Eduardo Espitia Cuchango

2010-09-01

Full Text Available Este documento describe la estructura de un sistema de inferencia difusa basado en relaciones booleanas. La teoría relacionada con lógica y conjuntos booleanos es una buena herramienta para el diseño de automatismos y sistemas digitales. Una variación con la cual se busca mejorar los sistemas basados en automatismos consiste en emplear conjuntos difusos en lugar de booleanos. Lo anterior se realiza con el objetivo de tener una acción continua en el actuador del automatismo. Al realizar esta variación y al aplicar la metodología de diseño de los sistemas de automatismos, aparecen los sistemas de inferencia difusa basados en relaciones booleanas.Aunque inicialmente esta propuesta se realizó considerando sistemas de automatismos, se observa que es posible extenderla a sistemas de inferencia difusa.

An auto-calibration procedure for empirical solar radiation models

NARCIS (Netherlands)

Bojanowski, J.S.; Donatelli, Marcello; Skidmore, A.K.; Vrieling, A.

2013-01-01

Solar radiation data are an important input for estimating evapotranspiration and modelling crop growth. Direct measurement of solar radiation is now carried out in most European countries, but the network of measuring stations is too sparse for reliable interpolation of measured values. Instead of

SU-F-E-19: A Novel Method for TrueBeam Jaw Calibration

Energy Technology Data Exchange (ETDEWEB)

Corns, R; Zhao, Y; Huang, V [Fraser Valley Cancer Centre - BC Cancer Agency, Surrey, BC (United Kingdom)

2016-06-15

Purpose: A simple jaw calibration method is proposed for Varian TrueBeam using an EPID-Encoder combination that gives accurate fields sizes and a homogeneous junction dose. This benefits clinical applications such as mono-isocentric half-beam block breast cancer or head and neck cancer treatment with junction/field matching. Methods: We use EPID imager with pixel size 0.392 mm × 0.392 mm to determine the radiation jaw position as measured from radio-opaque markers aligned with the crosshair. We acquire two images with different symmetric field sizes and record each individual jaw encoder values. A linear relationship between each jaw’s position and its encoder value is established, from which we predict the encoder values that produce the jaw positions required by TrueBeam’s calibration procedure. During TrueBeam’s jaw calibration procedure, we move the jaw with the pendant to set the jaw into position using the predicted encoder value. The overall accuracy is under 0.1 mm. Results: Our in-house software analyses images and provides sub-pixel accuracy to determine field centre and radiation edges (50% dose of the profile). We verified the TrueBeam encoder provides a reliable linear relationship for each individual jaw position (R{sup 2}>0.9999) from which the encoder values necessary to set jaw calibration points (1 cm and 19 cm) are predicted. Junction matching dose inhomogeneities were improved from >±20% to <±6% using this new calibration protocol. However, one technical challenge exists for junction matching, if the collimator walkout is large. Conclusion: Our new TrueBeam jaw calibration method can systematically calibrate the jaws to crosshair within sub-pixel accuracy and provides both good junction doses and field sizes. This method does not compensate for a larger collimator walkout, but can be used as the underlying foundation for addressing the walkout issue.

Calibration of a plastic detector PVT of large dimensions for the detection gamma radiation

International Nuclear Information System (INIS)

Armenteros Carmona, J. C.; Suarez navarro, M. J.; Gonzalez-gonzalez, J. A.; Pujol, L.

2011-01-01

This article describes the development work on the porch Rad Sentry Canberra brand that uses 2 plastic scintillation detectors PVT large (172 x 32 x 4 cm). In this paper we present the different calibration necessary for the proper functioning of equipment: channel-energy calibration, energy resolution, and efficiency-energy.

Invited Article: Deep Impact instrument calibration.

Science.gov (United States)

Klaasen, Kenneth P; A'Hearn, Michael F; Baca, Michael; Delamere, Alan; Desnoyer, Mark; Farnham, Tony; Groussin, Olivier; Hampton, Donald; Ipatov, Sergei; Li, Jianyang; Lisse, Carey; Mastrodemos, Nickolaos; McLaughlin, Stephanie; Sunshine, Jessica; Thomas, Peter; Wellnitz, Dennis

2008-09-01

Calibration of NASA's Deep Impact spacecraft instruments allows reliable scientific interpretation of the images and spectra returned from comet Tempel 1. Calibrations of the four onboard remote sensing imaging instruments have been performed in the areas of geometric calibration, spatial resolution, spectral resolution, and radiometric response. Error sources such as noise (random, coherent, encoding, data compression), detector readout artifacts, scattered light, and radiation interactions have been quantified. The point spread functions (PSFs) of the medium resolution instrument and its twin impactor targeting sensor are near the theoretical minimum [ approximately 1.7 pixels full width at half maximum (FWHM)]. However, the high resolution instrument camera was found to be out of focus with a PSF FWHM of approximately 9 pixels. The charge coupled device (CCD) read noise is approximately 1 DN. Electrical cross-talk between the CCD detector quadrants is correctable to <2 DN. The IR spectrometer response nonlinearity is correctable to approximately 1%. Spectrometer read noise is approximately 2 DN. The variation in zero-exposure signal level with time and spectrometer temperature is not fully characterized; currently corrections are good to approximately 10 DN at best. Wavelength mapping onto the detector is known within 1 pixel; spectral lines have a FWHM of approximately 2 pixels. About 1% of the IR detector pixels behave badly and remain uncalibrated. The spectrometer exhibits a faint ghost image from reflection off a beamsplitter. Instrument absolute radiometric calibration accuracies were determined generally to <10% using star imaging. Flat-field calibration reduces pixel-to-pixel response differences to approximately 0.5% for the cameras and <2% for the spectrometer. A standard calibration image processing pipeline is used to produce archival image files for analysis by researchers.

Invited Article: Deep Impact instrument calibration

International Nuclear Information System (INIS)

Klaasen, Kenneth P.; Mastrodemos, Nickolaos; A'Hearn, Michael F.; Farnham, Tony; Groussin, Olivier; Ipatov, Sergei; Li Jianyang; McLaughlin, Stephanie; Sunshine, Jessica; Wellnitz, Dennis; Baca, Michael; Delamere, Alan; Desnoyer, Mark; Thomas, Peter; Hampton, Donald; Lisse, Carey

2008-01-01

Calibration of NASA's Deep Impact spacecraft instruments allows reliable scientific interpretation of the images and spectra returned from comet Tempel 1. Calibrations of the four onboard remote sensing imaging instruments have been performed in the areas of geometric calibration, spatial resolution, spectral resolution, and radiometric response. Error sources such as noise (random, coherent, encoding, data compression), detector readout artifacts, scattered light, and radiation interactions have been quantified. The point spread functions (PSFs) of the medium resolution instrument and its twin impactor targeting sensor are near the theoretical minimum [∼1.7 pixels full width at half maximum (FWHM)]. However, the high resolution instrument camera was found to be out of focus with a PSF FWHM of ∼9 pixels. The charge coupled device (CCD) read noise is ∼1 DN. Electrical cross-talk between the CCD detector quadrants is correctable to <2 DN. The IR spectrometer response nonlinearity is correctable to ∼1%. Spectrometer read noise is ∼2 DN. The variation in zero-exposure signal level with time and spectrometer temperature is not fully characterized; currently corrections are good to ∼10 DN at best. Wavelength mapping onto the detector is known within 1 pixel; spectral lines have a FWHM of ∼2 pixels. About 1% of the IR detector pixels behave badly and remain uncalibrated. The spectrometer exhibits a faint ghost image from reflection off a beamsplitter. Instrument absolute radiometric calibration accuracies were determined generally to <10% using star imaging. Flat-field calibration reduces pixel-to-pixel response differences to ∼0.5% for the cameras and <2% for the spectrometer. A standard calibration image processing pipeline is used to produce archival image files for analysis by researchers.

Self-calibration of Cosmic Microwave Background Polarization Experiments

Science.gov (United States)

Keating, Brian G.; Shimon, Meir; Yadav, Amit P. S.

2013-01-01

Precision measurements of the polarization of the cosmic microwave background (CMB) radiation, especially experiments seeking to detect the odd-parity "B-modes," have far-reaching implications for cosmology. To detect the B-modes generated during inflation, the flux response and polarization angle of these experiments must be calibrated to exquisite precision. While suitable flux calibration sources abound, polarization angle calibrators are deficient in many respects. Man-made polarized sources are often not located in the antenna's far-field, have spectral properties that are radically different from the CMB's, are cumbersome to implement, and may be inherently unstable over the (long) duration these searches require to detect the faint signature of the inflationary epoch. Astrophysical sources suffer from time, frequency, and spatial variability, are not visible from all CMB observatories, and none are understood with sufficient accuracy to calibrate future CMB polarimeters seeking to probe inflationary energy scales of 1015 GeV. Both man-made and astrophysical sources require dedicated observations which detract from the amount of integration time usable for detection of the inflationary B-modes. CMB TB and EB modes, expected to identically vanish in the standard cosmological model, can be used to calibrate CMB polarimeters. By enforcing the observed EB and TB power spectra to be consistent with zero, CMB polarimeters can be calibrated to levels not possible with man-made or astrophysical sources. All of this can be accomplished for any polarimeter without any loss of observing time using a calibration source which is spectrally identical to the CMB B-modes.

Fast film dosimetry calibration method for IMRT treatment plan verification

International Nuclear Information System (INIS)

Schwob, N.; Wygoda, A.

2004-01-01

Intensity-Modulated Radiation Therapy (IMRT) treatments are delivered dynamically and as so, require routinely performed verification measurements [1]. Radiographic film dosimetry is a well-adapted method for integral measurements of dynamic treatments fields, with some drawbacks related to the known problems of dose calibration of films. Classically, several films are exposed to increasing doses, and a Net Optical Density (N.O.D) vs. dose sensitometric curve (S.C.) is generated. In order to speed up the process, some authors have developed a method based on the irradiation of a single film with a non-uniform pattern of O.D., delivered with a dynamic MLC. However, this curve still needs to be calibrated to dose by the means of measurements in a water phantom. It is recommended to make a new calibration for every series of measurements, in order to avoid the processing quality dependence of the film response. These frequent measurements are very time consuming. We developed a simple method for quick dose calibration of films, including a check of the accuracy of the calibration curve obtained

Investigation of Workplace-like Calibration Fields via a Deuterium-Tritium (D-T) Neutron Generator.

Science.gov (United States)

Mozhayev, Andrey V; Piper, Roman K; Rathbone, Bruce A; McDonald, Joseph C

2017-04-01

Radiation survey meters and personal dosimeters are typically calibrated in reference neutron fields based on conventional radionuclide sources, such as americium-beryllium (Am-Be) or californium-252 (Cf), either unmodified or heavy-water moderated. However, these calibration neutron fields differ significantly from the workplace fields in which most of these survey meters and dosimeters are being used. Although some detectors are designed to yield an approximately dose-equivalent response over a particular neutron energy range, the response of other detectors is highly dependent upon neutron energy. This, in turn, can result in significant over- or underestimation of the intensity of neutron radiation and/or personal dose equivalent determined in the work environment. The use of simulated workplace neutron calibration fields that more closely match those present at the workplace could improve the accuracy of worker, and workplace, neutron dose assessment. This work provides an overview of the neutron fields found around nuclear power reactors and interim spent fuel storage installations based on available data. The feasibility of producing workplace-like calibration fields in an existing calibration facility has been investigated via Monte Carlo simulations. Several moderating assembly configurations, paired with a neutron generator using the deuterium tritium (D-T) fusion reaction, were explored.

Radiation practices and radiation measurements

International Nuclear Information System (INIS)

2008-03-01

The guide presents the principal requirements on accuracy of radiation measurements and on the approval, calibration and operating condition inspections of radiation meters, together with requirements for dosimetric services measuring the individual radiation doses of workers engaged in radiation work (approved dosimetric services). The Guide also sets out the definitions of quantities and units used in radiation measurements. The radiation protection quantities used for assessing the harmful effects of radiation and for expressing the maximum values for radiation exposure (equivalent dose and effective dose) are set out in Guide ST 7.2. This Guide concerns measurements of ionizing radiation involved in radiation practices, the results of which are used for determining the radiation exposure of workers engaged in radiation work and members of the public, and of patients subject to the use of radiation in health services, or upon the basis of which compliance with safety requirements of appliances currently in use and of their premises of use or of the workplaces of workers is ensured. The Guide also concerns measurements of the radon concentration of inhaled air in both workplaces and dwellings. The Guide does not apply to determining the radiation exposure of aircrews, determination of exposure caused by internal radiation, or measurements made to protect the public in the event of, or in preparation for abnormal radiation conditions

Sistemas híbrido de produção de energia para sistema de comunicações rádio

OpenAIRE

Carreiras, José Manuel Patrício

2014-01-01

Mestrado em Sistemas de Energias Renováveis na Escola Superior de Tecnologia e Gestão do Instituto Politécnico de Viana do Castelo Este trabalho de projeto incidiu sobre o dimensionamento de cinco sistemas Autónomos de produção de energia para alimentação de Pontos repetidores do sistema de comunicação e sua implementação. O presente trabalho iniciou-se em 2006 quando por motivos profissionais foi necessário construir um sistema de comunicação de suporte ao sistema de telegestã...

Um modelo de enfermagem como sistema complexo adaptativo

Directory of Open Access Journals (Sweden)

Mariana Vieira

2009-01-01

Full Text Available El surgimiento y el uso de los sistemas complejos adaptativos suplieron la necesidad de contar con una nueva alternativa, recurriendo a los paradigmas existentes. En cuanto al sistema de salud y de enfermería, ambos pueden verse como sistemas complejos adaptativos al aplicar un modelo visual que debe ser explorado para potenciar la complejidad de la ciencia de enfermería y de cuidados de salud. Desde esta perspectiva, el/la enfermero/a es un sistema complejo adaptativo, dinámico que interactúa, pero también es agente de un sistema complejo adaptativo en una unidad de enfermería, que a la vez es un sistema complejo adaptativo en una organización de la salud. Hoy en día la/el profesional de enfermería busca actualizarse y cualificarse en diversas especialidades, que van desde enfermería neonatal hasta cuidados geriátricos, para ejecutar sus actividades y visualizar su ambiente laboral desde la perspectiva de un sistema complejo. En consecuencia, la organización del sistema de cuidados permite, mediante los sistemas complejos, apoyarse en el saber compartido de los diversos profesionales y en el trabajo en equipo para disfrutar la complicidad de la cadena cliente-usuario-profesionales.

Del Actual Sistema de Enfermedad a un verdadero Sistema de Salud

Directory of Open Access Journals (Sweden)

Lidice Alvarez-Miño

2018-01-01

Full Text Available Esta editorial tiene como objetivo generar una reflexión y abrir el debate sobre el sistema actual de salud que se refleja en prácticas naturalizadas  que se contradicen con la esencia del significado de la salud. Se trata de la costumbre de acudir al sistema de salud únicamente cuando se considera que se está enfermo, o peor aún, la equivalencia reduccionista y casi automática del concepto de salud como sinónimo de medicina.

Overview of individual monitoring and calibration of radiation monitors in the country; Panorama da monitoração individual e calibração de monitores de radiação no país

Energy Technology Data Exchange (ETDEWEB)

Alencar, M.A.V.; Patrão, K.C.S.; Ferreira, P.R.R.; Matta, L.E.S.C.; Peres, S.S.; Silva, F.C.A. da, E-mail: vallim@ird.gov.br [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

Since 1995, the Institute of Radioprotection and Dosimetry (IRD/CNEN-RJ) has been responsible for the certification of instrument calibration laboratories and monitoring of occupationally exposed individuals (IOE), as well as monitoring and auditing the activities of eleven individual monitoring services (SMIE) and six instrument calibration laboratories (LCI) in the country. The work presents an overview of the number of IOE monitored and calibrated radiation monitors, from 2008 to 2016. The data were obtained through a census with the SMIE and LCI. The results show that in this period there was an increase of around 47% in the total number of IOE monitored and approximately 40% in the number of instrument calibrations. It was also observed the reduction of dosimetric film use and the beginning of OSLD monitoring.

Dosimetric methodology and reference system for diagnostic level X radiation

International Nuclear Information System (INIS)

Potiens, Maria da Penha Albuquerque

1999-01-01

Several methodologies for the calibration of diagnostic radiology instruments were developed and established at the Calibration Laboratory of IPEN. These established radiation qualities are recommended by international standards. The methods may be used in the calibration procedures of survey meters used in radiation protection measurements (scattered radiation), instruments used in direct beams (attenuated and non attenuated beams) and quality control instruments. A reference system was proposed using two identical ionization chambers developed at IPEN. They differ only by the collecting electrode material, one of aluminium and the other of graphite. The different energetic dependence of the chamber's response provided a ratio related to the tube potential. The variation of only 0.28%, from 14.3 to 111 keV, on the energetic dependence of the graphite electrode chamber, provided the possibility of air kerma rate determination in the studied radiation beams. (author)

In-flight calibration of the ISGRI camera

International Nuclear Information System (INIS)

Terrier, R.; Lebrun, F.; Belanger, G.; Blondel, C.; David, P.; Goldoni, P.; Goldwurm, A.; Gros, A.; Laurent, P.; Malaguti, G.; Sauvageon, A.; Bazzano, A.; Ubertini, P.; Segreto, A.; Malaguti, G.; Bird, A.J.

2003-01-01

ISGRI, the IBIS low energy camera (15 keV-1 MeV) on board INTEGRAL, is the first large CdTe gamma-ray imager in orbit. We present here an overview of the ISGRI in-flight calibrations performed during the first months after launch. We discuss the stability of the camera as well as the CdTe pixels response under cosmic radiation. The energy calibrations were done using lead and tungsten fluorescence lines and the 22 Na calibration unit. Thermal effects and charge correction algorithm are discussed, and the resulting energy resolution is presented. The ISGRI background spatial and spectral non-uniformity is also described, and some image correction results are presented. ISGRI, despite a few unexpected features like zero rise time events, performs well with only 4,5% noisy or disabled pixels. Thermal effects are at the origin of the largest difference between ground and in-flight data. Correcting for these effects yields good spectral performances close to the expectations with 8.4% at 59.3 keV and 4.9% at 511 keV. The resolution in the high energy band is broader than before launch because of residual rise time gains uncertainties. Handling of these errors requires a larger amount of calibration data than what is available today

Solar radiation modeling and measurements for renewable energy applications: data and model quality

International Nuclear Information System (INIS)

Myers, Daryl R.

2005-01-01

Measurement and modeling of broadband and spectral terrestrial solar radiation is important for the evaluation and deployment of solar renewable energy systems. We discuss recent developments in the calibration of broadband solar radiometric instrumentation and improving broadband solar radiation measurement accuracy. An improved diffuse sky reference and radiometer calibration and characterization software for outdoor pyranometer calibrations are outlined. Several broadband solar radiation model approaches, including some developed at the National Renewable Energy Laboratory, for estimating direct beam, total hemispherical and diffuse sky radiation are briefly reviewed. The latter include the Bird clear sky model for global, direct beam, and diffuse terrestrial solar radiation; the Direct Insolation Simulation Code (DISC) for estimating direct beam radiation from global measurements; and the METSTAT (Meteorological and Statistical) and Climatological Solar Radiation (CSR) models that estimate solar radiation from meteorological data. We conclude that currently the best model uncertainties are representative of the uncertainty in measured data

Solar radiation modeling and measurements for renewable energy applications: data and model quality

Energy Technology Data Exchange (ETDEWEB)

Myers, D.R. [National Renewable Energy Laboratory, Golden, CO (United States)

2005-07-01

Measurement and modeling of broadband and spectral terrestrial solar radiation is important for the evaluation and deployment of solar renewable energy systems. We discuss recent developments in the calibration of broadband solar radiometric instrumentation and improving broadband solar radiation measurement accuracy. An improved diffuse sky reference and radiometer calibration and characterization software for outdoor pyranometer calibrations are outlined. Several broadband solar radiation model approaches, including some developed at the National Renewable Energy Laboratory, for estimating direct beam, total hemispherical and diffuse sky radiation are briefly reviewed. The latter include the Bird clear sky model for global, direct beam, and diffuse terrestrial solar radiation; the Direct Insolation Simulation Code (DISC) for estimating direct beam radiation from global measurements; and the METSTAT (Meteorological and Statistical) and Climatological Solar Radiation (CSR) models that estimate solar radiation from meteorological data. We conclude that currently the best model uncertainties are representative of the uncertainty in measured data. (author)

Note: Calibration of EBT3 radiochromic film for measuring solar ultraviolet radiation

Energy Technology Data Exchange (ETDEWEB)

Chun, S. L. [Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong (Hong Kong); Yu, P. K. N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong (Hong Kong); State Key Laboratory in Marine Pollution, City University of Hong Kong, Kowloon Tong (Hong Kong)

2014-10-01

Solar (UVA + UVB) exposure was assessed using the Gafchromic EBT3 film. The coloration change was represented by the net reflective optical density (Net ROD). Through calibrations against a UV-tube lamp, operational relationships were obtained between Net ROD and the (UVA + UVB) exposures (in J cm⁻²p or J m⁻²). The useful range was from ~0.2 to ~30 J cm⁻². The uniformity of UV irradiation was crucial for an accurate calibration. For solar exposures ranging from 2 to 11 J cm⁻², the predicted Net ROD agreed with the recorded values within 9%, while the predicted exposures agreed with the recorded values within 15%.

System for calibration of instruments of x-ray measurement (CIR-X) applying the PGCS; Sistema para calibracion de instrumentos de medicion de rayos X (CIR-X) aplicando el PGCS

Energy Technology Data Exchange (ETDEWEB)

Gaytan G, E.; Rivero G, T.; Cruz E, P.; Tovar M, V.M.; Vergara M, F.J. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: egg@nuclear.inin.mx

2007-07-01

The Department of Metrology of Ionizing Radiations of the ININ carries out calibration of instruments for X-ray measurement that determine the operation parameters in X-ray diagnostic machines of the health and private sectors. To facilitate this task, the Department of Automation and Instrumentation developed a system for acquisition and signals processing coming from a reference voltage divider with traceability at NIST that is connected directly to the X-rays tube. The system is integrated by the X-ray unit, the X-ray measurement equipment Dynalizer IIIU of RADCAL, a data acquisition card, a personal computer and the acquisition software and signals processing. (Author)

O sistema social da saúde: conceito, limites e possibilidades

Directory of Open Access Journals (Sweden)

Sandra Regina Martini Vial

2014-06-01

Full Text Available Discutem-se as possibilidades de definir o sistema da saúde como um sistema social, diferenciado funcionalmente, a partir da ótica da Teoria dos Sistemas Sociais, utilizando os pressupostos gerais da Teoria e a estrutura apresentada por Niklas Luhmann sobre o sistema médico. Apresentam-se alguns “desassossegos” provocados pela Teoria; as possíveis relações entre o sistema da saúde e o que Luhmann chamou de sistema médico e como esse sistema, atualmente, pode ser considerado sistema da saúde; e, por fim, a nossa concepção do sistema da saúde na atualidade.

Radiation detectors

International Nuclear Information System (INIS)

2013-01-01

This sixth chapter presents the operational principles of the radiation detectors; detection using photographic emulsions; thermoluminescent detectors; gas detectors; scintillation detectors; liquid scintillation detectors; detectors using semiconductor materials; calibration of detectors; Bragg-Gray theory; measurement chain and uncertainties associated to measurements

Absolute calibration of in vivo measurement systems using magnetic resonance imaging and Monte Carlo computations

International Nuclear Information System (INIS)

Mallett, M.W.

1991-01-01

Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. This method uses magnetic resonance imaging (MRI) to determine the anatomical makeup of an individual. A new MRI technique is also employed that is capable of resolving the fat and water content of the human tissue. This anatomical and biochemical information is used to model a mathematical phantom. Monte Carlo methods are then used to simulate the transport of radiation throughout the phantom. By modeling the detection equipment of the in vivo measurement system into the code, calibration factors are generated that are specific to the individual. Furthermore, this method eliminates the need for surrogate human structures in the calibration process. A demonstration of the proposed method is being performed using a fat/water matrix