Activity standardisation of Si at IRA-METAS.

This work explores the primary activity standardisation of Si as part of the SINCHRON project that aims at filling the geochronological dating gap by making a new precise measurement of the half-life of this nuclide. The stability of some of the radioactive test solutions, providing Si as hexafluorosilicic acid (HSiF), was monitored over long periods, pointing to the adequate sample composition and vial type to ensure stability. These solutions were standardised using liquid scintillation counting with the triple to double coincidence ratio (TDCR) technique and the CIEMAT-NIST efficiency tracing (CNET) method.

Activity standardisation of Lu.

Lu decays through low-energy β- and γ-emissions in addition to conversion and Auger electrons. To support the use of this radiopharmaceutical in Switzerland, a Lu solution was standardised using the β-γ coincidence technique, as well as the TDCR method. The solution had no Lu impurity.

Activity Measurement of Sc and Calibration of Activity Measurement Instruments on Production Sites and Clinics.

Sc is a promising radionuclide for positron emission tomography (PET) in nuclear medicine. As a part of the implementation of a production site for Sc, precise knowledge of the activity of the product is necessary. At the Paul Scherrer Institute (PSI) and the University of Bern (UniBE), Sc is produced by enriched CaO-target irradiation with a cyclotron.

Half-life measurement of Sc and Sc.

The half-lives of Sc and Sc were measured by following their decay rate using several measurement systems: two ionization chambers and three γ-spectrometry detectors with digital and/or analogue electronics. For Sc, the result was the combination of seven half-life values giving a result of 4.042(7) h, which agrees with the last reported value of 4.

Synthesis of a Zinc Hydroxystannate/Sepiolite Hybrid Additive to Avoid Fire Propagation and Reduce Smoke Emission of EPDM Rubber Nanocomposites.

A zinc hydroxystannate/sepiolite (SEPZHS) hybrid additive was successfully prepared following a facile wet chemical route synthesis where zinc hydroxystannate (ZHS) nanoparticles were grown on the sepiolite's surface. SEPZHS particles have a fibrillar structure with ZHS nanoparticles homogeneously dispersed and with significantly smaller particle sizes than the synthesized ZHS nanoparticles alone. Sepiolite and SEPZHS were organically modified and introduced in a basic ethylene propylene diene monomer rubber (EPDM) formulation for cable to evaluate the nanocomposite behavior under direct fire sources.

Precise activity measurements of medical radionuclides using an ionization chamber: a case study with Terbium-161.

Background: Tb draws an increasing interest in nuclear medicine for therapeutic applications. More than 99% of the emitted gamma and X-rays of Tb have an energy below 100 keV. Consequently, precise activity measurement of Tb becomes inaccurate with radionuclide dose calibrators when using inappropriate containers or calibration factors to account for the attenuation of this low energy radiation.

Ytterbium-175 half-life determination.

Yb is a radionuclide that can be generated by neutron capture on Yb and whose decay properties make it useful for developing therapeutic radiopharmaceuticals. As it happens with many of the emerging radionuclides for medical uses in recent years, its nuclear data were determined decades ago and are not thoroughly documented nor accurate enough for metrological purposes. The last documented reference for the Yb half-life value is 4.

Determination of the gamma and X-ray emission intensities of erbium-169.

The gamma and X-ray emission intensities of Er were determined using radionuclidically pure Er. The activity of the Er source was standardized by the triple-to-double-coincidence ratio technique. Three independent measurements were performed to measure the emission intensities using calibrated high-purity germanium spectrometers.

Determination of the gamma and X-ray emission intensities of terbium-161.

In this study, the gamma and X-ray emission intensities of Tb were determined using a high-purity germanium spectrometer. The samples used were previously standardised by coincidence counting and Triple to Double Coincidence Ratio (TDCR) methods. A total of 28 gamma-rays and 4 X-rays were measured and compared with previous measurements performed more than 30 years ago.

Activity standardisation of Tb.

Tb, which emits low-energy β- and γ-particles in addition to conversion and Auger electrons, has aroused increased interest for medical imaging and therapy. To support the use of this radionuclide, aTb solution was standardised using the β-γ coincidence technique, as well as the TDCR method. The solution had 4.

Environmental impact of nano-functionalized construction materials: leaching of titanium and nitrates from photocatalytic pavements under outdoor conditions.

There is a growing use of nano-functionalized construction materials, which contain nanoparticles embedded in their bulk or deposited on their surfaces. In the case of photocatalytic materials, nano-TiO is usually added to provide it's functionality. One concern about these materials, in addition to release of nanoparticles as airborne, is that they can be leached into the aquatic environment.

Evaluation of digital pulse processing techniques for a β-γ coincidence counting system.

Signal processing is a core part of any electronic chain for radioactivity measurement systems and can influence measurement results drastically. A thorough study of the different alternatives for this treatment is especially worthwhile when developing a new digital system. This article describes an evaluation performed to optimize the digital pulse processing stage of the β-γ coincidence counting system at the Institute of Radiation Physics (IRA) designated laboratory for the activity unit.

Determination of Tb half-life by three measurement methods.

The radiolanthanide Tb is being studied as an alternative to Lu for targeted radionuclide tumor therapy. Both β-particle emitters show similar chemical behavior and decay characteristics, but Tb delivers additional conversion and Auger electron emissions that may enhance the therapeutic efficacy. In this study, the half-life of Tb was determined by a combination of three independent measurement systems: reference ionization chamber (CIR, chambre d'ionization de référence), portable ionization chamber (TCIR) and a CeBr γ-emission detector with digital electronics.

A portable precision ionization chamber: The transfer ionization reference chamber.

A portable instrument was developed at the Institute of Radiation Physics (IRA) for on-site radionuclides measurements. It will enable the measurement of short-lived radionuclides in nuclear medicine departments or isotope production centres. The system involves an ionization chamber read directly by an electrometer and it was optimized to ensure a good reproducibility through the selection of an appropriate vial, filling volume and source position in the well chamber, as well as monitoring the external background and performing a detailed uncertainty estimation.

Fast digital 4πβ-4πγ coincidence counting with offline analysis at IRA.

IRA recently launched a project to digitize all the data acquisition systems it uses for primary radionuclide standardizations. It is well-known that the digital approach presents numerous advantages over the traditional analog electronics such as information losslessness, scalability, online and/or offline data processing, and it is also a solution to the growing difficulties to repair or renew ageing modules. As a first step in this wider program, our institute set-up a 4πβ-4πγ digital coincidence counting system, with FPGA (Field Programmable Gate Array)-based commercial boards from National Instruments (NI), to perform data acquisition and offline data analysis.

On the influence of the vacancy distribution on the structure and ionic conductivity of A-site-deficient Li(x)Sr(x)La(2/3-x)TiO3 perovskites.

The crystal structure and dielectric properties of slowly cooled A-site-deficient perovskites Li(x)Sr(x)La(2/3-x)□(1/3-x)TiO(3) (0.04 ≤ x ≤ 0.33) have been investigated by powder X-ray diffraction (XRD), impedance spectroscopy, and (7)Li NMR techniques.