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Scientific news from division 6

News 2006

Together with other partners of the Collaboration of European Low-level Underground Laboratories (CELLAR), PTB has participated for the first time in the measurement of activated metal samples from experiments at the Joint European Torus (JET). The measurement of the activation products is aimed at getting information about the spectrum of the neutrons and charged particles in the plasma.

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Within the scope of the Euromet 909 Project, an ionization chamber of the Bulgarian national metrology institute NCM is calibrated with activity standards of PTB. The project, which covers the setting up of an automated data acquisition system, calibration and establishment of procedures for evaluation and quality control, will enable the NCM to offer calibration services for activity measurements...

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By measurements of the Pb-210 and Po-210 content performed on more than 50 lead samples of an industrial company, PTB participated in decisions on the selection of the correct lead with a total mass of 2000 t for a neutrino experiment. By measurements on glass raw materials and final products, PTB supports a large German company in the compliance with the quality requirements for an extremely low...

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The Federal States committee ‘X-ray Ordinance’ within the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety decided in March 2001 that the requirements for the safety devices of high-protection- and full protection devices have to fulfil high technical requirements. These requirements, on the one hand and details of the type tests performed by PTB on the other hand, are...

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Experimental determination of the differential 0° neutron emission cross section for the 13C(p,n)13N reaction as a function of the proton energy Ep, for the quantitative determination of the neutron contamination in the high energy photon reference fields according to ISO 4037. New mixed photon/neutron field for the calibration of e.g. TEPCs.

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PTB has been calibrating 192Ir-sources for brachytherapy for nearly 15 years and recently also 60Co-sources in terms of Reference Air Kerma Rate (RAKR). The trend towards the use of increasingly strong sources for therapy made it necessary, for reasons of radiation protection, to set up a new calibration facility for these highly radioactive radiation sources which is remotely controlled.

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This intercomparison takes place between autumn 2005 and autumn 2007. The ten participating institutions come from Germany, Switzerland and Austria. During the first measuring period, a total of 188 dosemeters was exposed at three different PTB measuring sites. 57 dosemeters were additionally irradiated in PTB photon fields. First results were obtained concerning the distribution of the measured...

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In cooperation with the company QSA Global GmbH, Braunschweig, PTB has organized a national comparison for activity determination of Tc-99m in hospitals and nuclear-medical practices. The data reported by the participants and later evaluated at PTB showed - compared to similar projects carried out at an earlier date - a slight improvement of the quality. The evaluation, however, also showed the...

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Scientists from the University of Kiel (Germany) developed a sophisticated system of particle detector telescopes for NASA’s STEREO mission. These SEPT modules (Solar Electron and Proton Telescope) detect and distinguish energetic protons and electrons from the Sun. The energy calibration and detection efficiency of the particle telescopes for protons and alpha particles with energies from 0.07...

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At present, a thoron progeny chamber is being established for the measurement of thoron progenies within the scope of a project promoted by the Federal Ministry of Environment, Nature Protection and Reactor Safety. This chamber is composed of an accessible air-conditioned testing chamber in which the environmental parameters temperature, air humidity and aerosol content can be adjusted and...

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The uncertainty budget for the secondary standard measurement system for the dose to water based on alanine/ESR was established. The relative standard measurement uncertainty is 0.15% for 25 Gy, 0.53% for 5 Gy and 1.5% for 2 Gy, respectively.

The given uncertainties are valid for irradiations in 60Co, excluding the uncertainty of the primary standard.

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In the context of the project "Determination of the Relative Biological Effectiveness for high-energy, quasi-monoenergetic photon radiation" which is funded by the "Bundesamt für Strahlenschutz", the quasi-monoenergetic photon beam available at the PTB (photon energies 6...7 MeV) was calibrated in terms of the absorbed dose to water. Five samples of human blood were irradiated in this beam with...

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The electronic personal neutron dosemeter DOS-2002, developed at the PTB, has been successfully transferred to industry. Based on this device, a new prototype dosemeter was developed which shows an improved response to high energy neutrons and which is thus suited for neutron monitoring at high-energy accelerators.

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With the aid of a water calorimeter, it was possible to determine the radiation quality correction factors kQ for 8 MV and 16 MV photon radiation for different ionization chambers of the types NE2571 and NE2561. The standard measurement uncertainty of the experimentally determined kQ factors is approx. 0.3% for an individual ionization chamber. Hence, it would be possible to reduce the ...

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When the attenuation properties of protective X-ray clothing are measured, the scattered and fluorescence radiation generated by the protective material itself must also be completely determined in the attenuated beam. For this purpose, PTB has developed a new measurement method which - compared to the methods so far applied - is much easier to realize, gets along with smaller material samples and...

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For the determination of absorbed dose to water under reference conditions at the point of measurement in a water phantom, a large transmission ionization chamber, mounted in front of the water phantom, is frequently used in the photon radiation field of a linear accelerator in order to monitor the radiation. The usual correction of the air density dependence of the response of this monitor...

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Among other devices, new digital mammography facilities, whose X-ray spectra considerably differ from those of conventional facilities, are used for "mammography screening". However, the dose response of modern diagnostic dosimeters with semiconductors depends rather sensitively on the spectral shape of the X-radiation. PTB has, therefore, established new X-radiation qualities for mammography and...

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Together with other partners of the Collaboration of European Low-level Underground Laboratories (CELLAR), PTB has participated for the first time in the measurement of activated metal samples from experiments at the Joint European Torus (JET). The measurement of the activation products is aimed at getting information about the spectrum of the neutrons and charged particles in the plasma.

[ more ]

Within the scope of the Euromet 909 Project, an ionization chamber of the Bulgarian national metrology institute NCM is calibrated with activity standards of PTB. The project, which covers the setting up of an automated data acquisition system, calibration and establishment of procedures for evaluation and quality control, will enable the NCM to offer calibration services for activity measurements...

[ more ]

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