Scientific news from Division 6

For the first time, two international comparisons are performed in radiation protection dosimetry. Both EUROMET comparisons are organized by PTB. In photon dosimetry, realization of the depth personal dose H_p(10) is compared, and realization of the superficial personal dose H_p(0.07) in the comparison with beta radiation. For both comparisons, new measuring instruments, which have so far...

The determination of chromosome aberrations is a sensitive, biological procedure to estimate the dose of ionizing radiation which has been received by an individual. For the systematic investigation of specific influence factors on the validity and reliability of the dose estimation of a radiation exposure, blood samples were irradiated, among others, in the intensive, collimated neutron field at...

The Virtual European Radionuclide Metrology Institute (VERMI) is an initiative of European metrology institutes aimed at maintaining the high quality in radionuclide metrology which is endangered by staff reductions. The PTB, which has helped to bring VERMI into being, actively participates in the configuration of workshops which, as intensive qualifying measures, also benefit its own junior...

In the last few years, PTB has participated in two large comparison measurements in the field of environmental radioactivity, whose results now led to the determination of reference values for the activity of alpha-, beta- and gamma-ray emitting radionuclides in the two materials (fish flesh and seaweed). The reference materials can be obtained from IAEA or NIST.

In the last few...

Within the scope of quality assurance in radon metrology, PTB was in charge of an international intercomparison performed as Euromet Project. Under project number Euromet 657 or BIPM supplementary comparison EUROMET.RI(II)-S1 "Comparison of calibration facilities for the radon activity concentration", this project is registered with Euromet and BIPM with a total of 12 participants. Information...

In the period under report, Working Group 6.11 has participated in a comparison for activity determination on a ³²P solution and sent activity standards of the nuclides ⁵⁷Co, ¹⁰⁹Cd, ¹¹¹In and ²⁰¹Tl to the international reference system SIR at the BIPM. In addition, an activity standard of the radioactive inert gas ²²²Rn and a solution of the short-lived radionuclide ¹⁸F were forwarded for...

The EU project EVIDOS was successfully completed.


As part of the EVIDOS research project (“Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields") supported by the European Commission, workplace neutron fields were characterized at several facilities, and the readings of a wide range of neutron dosimeters were determined and analyzed after major...

The stability of the dose rate and radiation quality in high-energy photon and electron reference radiation fields on the PTB’s linear accelerator could be clearly improved by different modifications of the accelerator.

PTB has a linear accelerator of type Philips SL 75/20 at its disposal which generates reference radiation fields of high-energy photon and electron radiation....

Since the beginning of the year, PTB has offered calibrations of well-type ionization chambers and therapy chambers in the Krieger phantom to indicate the characteristic dose rate or the reference air kerma rate.

Before radiation sources are used for the first time on a patient, the reference air kerma rate of the sources used for intracavitary and interstitial brachytherapy must be...

With the aid of a water-tight pinpoint ionization chamber developed at PTB, a complete 3d-distribution of the water absorbed dose rate has for the first time been measured directly in the water phantom in the near field of ¹⁹²Ir and ⁶⁰Co brachytherapy sources.

In addition to ¹⁹²Ir high-dose rate sources (HDR sources), ⁶⁰Co HDR brachytherapy sources have later also been used for the...

A water calorimeter allows the water absorbed dose to be measured by definition. Due to its compact construction (outer dimensions approx. 65 cm × 60 cm × 65 cm [L×W×H]), the newly constructed calorimeter can also be used as transfer calorimeter for therapeutic radiation fields and is ready for on-site operation within approx. 18 h. At PTB, this water calorimeter is used to determine the...

The secondary standard measuring facility for the absorbed dose to water in high-energy radiation fields on the basis of Alanin/ESR could be improved by a new probes positioning device. At 5 Gy, the relative reproducibility standard deviation now amounts to 0.4%, and at 25 Gy, a deviation of 0.2% is achieved.

The reproducibility standard deviation of the secondary standard measuring...

As a result of a solar eruption on January 20, the earth was hit by so many high-energy particles that radiation exposure at flight altitudes temporarily increased. The additional radiation exposure at flight altitudes was estimated by PTB and other European partners to be less than 0.2 mSv. This corresponds to approx. 1 % of the annual limiting value permitted for persons occupationally exposed...

To measure the radiation exposure at flight altitudes by cosmic radiation, PTB has developed a measuring system in a handy suitcase ("flight case"). In the very complex radiation fields of natural cosmic radiation, it furnishes reliable measurements of the existing ambient dose equivalent. The flight case travelled several months on board of an airbus, and a calculation program was...

Within the scope of a research project which will be funded until the end of 2006 by the Federal Office for Radiation Protection with a total amount of 305000,- EUR, a reference field for thoron decay products will be established at PTB.

As an extension to a research project concluded in 2003 (“Manufacture and investigation of defined thoron decay product reference fields for...

The evaluation procedures of radiobiological experiments performed on the microbeam were extended and refined so that the radiation effect can now be made visible and quantified for each individual cell. Within the scope of an EU project, the module serves to investigate the so-called bystander effect which characterizes the occurrence of a radiation effect in non-irradiated cells when...

A new building which will accommodate the electron accelerator facility is being established on the PTB premises in Braunschweig. It will bear the name "Glocker Building".

The design phase of the new electron accelerator facility for dosimetry of high-energy photon and electron radiation has been completed. The facility consists of two clinical accelerators of type ELEKTA-Precise and a...

For a large number of flat chambers of types Roos, Markus and Advanced Markus, the perturbation correction factors p_Co were determined. As the result of these investigations, the new version of standard DIN 6800-2 states type-specific p_Co-values for these flat chamber types.

Modern dosimetry protocols as, for example, DIN 6800-2 or IAEA TRS-398, recommend the use of flat chambers to...

For the first time, two international comparisons are performed in radiation protection dosimetry. Both EUROMET comparisons are organized by PTB. In photon dosimetry, realization of the depth personal dose H_p(10) is compared, and realization of the superficial personal dose H_p(0.07) in the comparison with beta radiation. For both comparisons, new measuring instruments, which have so far...

The determination of chromosome aberrations is a sensitive, biological procedure to estimate the dose of ionizing radiation which has been received by an individual. For the systematic investigation of specific influence factors on the validity and reliability of the dose estimation of a radiation exposure, blood samples were irradiated, among others, in the intensive, collimated neutron field at...

The Virtual European Radionuclide Metrology Institute (VERMI) is an initiative of European metrology institutes aimed at maintaining the high quality in radionuclide metrology which is endangered by staff reductions. The PTB, which has helped to bring VERMI into being, actively participates in the configuration of workshops which, as intensive qualifying measures, also benefit its own junior...

In the last few years, PTB has participated in two large comparison measurements in the field of environmental radioactivity, whose results now led to the determination of reference values for the activity of alpha-, beta- and gamma-ray emitting radionuclides in the two materials (fish flesh and seaweed). The reference materials can be obtained from IAEA or NIST.

In the last few...

Within the scope of quality assurance in radon metrology, PTB was in charge of an international intercomparison performed as Euromet Project. Under project number Euromet 657 or BIPM supplementary comparison EUROMET.RI(II)-S1 "Comparison of calibration facilities for the radon activity concentration", this project is registered with Euromet and BIPM with a total of 12 participants. Information...

In the period under report, Working Group 6.11 has participated in a comparison for activity determination on a ³²P solution and sent activity standards of the nuclides ⁵⁷Co, ¹⁰⁹Cd, ¹¹¹In and ²⁰¹Tl to the international reference system SIR at the BIPM. In addition, an activity standard of the radioactive inert gas ²²²Rn and a solution of the short-lived radionuclide ¹⁸F were forwarded for...