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Davkov V.I.,Joint Institute for Nuclear Research | Gregor I.,German Electron Synchrotron | Haas D.,University Of Genve | Mouraviev S.V.,Pn Lebedev Institute Of Physics | And 9 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

A small prototype detector based on high pressure thin-walled tubes (straws) has been developed and its parameters have been studied on a bench at JINR, Dubna, and SPS at CERN. The inner diameter of the straws is 9.53 mm. The pressure of the active gas mixture Ar/CO2 (80/20) was varied from 1 to 5 bar. The best spatial resolution achieved in this pressure range is ∼40 μm. Both the high efficiency and high rate capability are retained. © 2011 Published by Elsevier B.V. Source

Amiot M.N.,CEA Saclay Nuclear Research Center | Chiste V.,CEA Saclay Nuclear Research Center | Fitzgerald R.,U.S. National Institute of Standards and Technology | Juget F.,Institute of Radiation Physics | And 4 more authors.

Pressurized re-entrant (or 4π) ionization chambers (ICs) connected to current-measuring electronics are used for activity measurements of photon emitting radionuclides and some beta emitters in the fields of metrology and nuclear medicine. As a secondary method, these instruments need to be calibrated with appropriate activity standards from primary or direct standardization. The use of these instruments over 50 years has been well described in numerous publications, such as the Monographie BIPM-4 and the special issue of Metrologia on radionuclide metrology (Ratel 2007 Metrologia 44 S7-16, Schrader1997 Activity Measurements With Ionization Chambers (Monographie BIPM-4) Schrader 2007 Metrologia 44 S53-66, Cox et al 2007 Measurement Modelling of the International Reference System (SIR) for Gamma-Emitting Radionuclides (Monographie BIPM-7)). The present work describes the principles of activity measurements, calibrations, and impurity corrections using pressurized ionization chambers in the first part and the uncertainty analysis illustrated with example uncertainty budgets from routine source-calibration as well as from an international reference system (SIR) measurement in the second part. © 2015 BIPM & IOP Publishing Ltd. Source

Fitzgerald R.,U.S. National Institute of Standards and Technology | Bailat C.,Institute of Radiation Physics | Bobin C.,CEA Saclay Nuclear Research Center | Keightley J.D.,National Physical Laboratory United Kingdom

The 4πβ-γ coincidence counting method and its close relatives are widely used for the primary standardization of radioactivity. Both the general formalism and specific implementation of these methods have been well-documented. In particular, previous papers contain the extrapolation equations used for various decay schemes, methods for determining model parameters and, in some cases, tabulated uncertainty budgets. Two things often lacking from experimental reports are both the rationale for estimating uncertainties in a specific way and the details of exactly how a specific component of uncertainty was estimated. Furthermore, correlations among the components of uncertainty are rarely mentioned. To fill in these gaps, the present article shares the best-practices from a few practitioners of this craft. We explain and demonstrate with examples of how these approaches can be used to estimate the uncertainty of the reported massic activity. We describe uncertainties due to measurement variability, extrapolation functions, dead-time and resolving-time effects, gravimetric links, and nuclear and atomic data. Most importantly, a thorough understanding of the measurement system and its response to the decay under study can be used to derive a robust estimate of the measurement uncertainty. © 2015 BIPM & IOP Publishing Ltd. Source

Juget F.,Institute of Radiation Physics | Bailat C.,Institute of Radiation Physics | Bochud F.,Institute of Radiation Physics
Applied Radiation and Isotopes

We report the performances of a double focusing magnetic beta spectrometer. The energy resolution was measured using conversion peaks of Cs-137 and Ba-133 at 0.73% for 624. keV, and 1.33% for 124. keV. The counting efficiency as a function of the energy was estimated using a P-32 source and was used to correct the measured spectra of Cs-137. The result was compared with the theoretical spectrum and we found a good agreement. © 2013 Elsevier Ltd. Source

Bailat C.,Institute of Radiation Physics | Bochud F.,Institute of Radiation Physics | Juget F.,Institute of Radiation Physics | Buchillier T.,Institute of Radiation Physics
Applied Radiation and Isotopes

We developed a method of sample preparation using epoxy compound, which was validated in two steps. First, we studied the homogeneity within samples by scanning tubes filled with radioactive epoxy. We found within-sample homogeneity better than 2%. Then, we studied the homogeneity between samples during a 4.5. h dispensing time. The homogeneity between samples was found to be better than 2%. This study demonstrates that we have a validated method, which assures the traceability of epoxy samples. © 2013 Elsevier Ltd. Source

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