Search for the decay of nature's rarest isotope 180m^{\rm {180m}}Ta

$^{\rm {180m}}$Ta is the rarest naturally occurring quasi-stable isotope and the longest lived metastable state which is known. Its possible decay via the $\beta^-$ or the electron capture channel has never been observed. This article presents a search for the decay of $^{\rm {180m}}$Ta with an ultra low background Sandwich HPGe gamma spectrometry setup in the HADES underground laboratory. No signal is observed and improved lower partial half-life limits are set with a Bayesian analysis to $5.8\cdot10^{16}$ yr for the $\beta^-$ channel and $2.0\cdot10^{17}$ yr for the electron capture channel (90% credibility). The total half-life of $^{\rm {180m}}$Ta is longer than $4.5\cdot10^{16}$ yr. This is more than a factor of two improvement compared to previous searches

Detection of 106Ru, via the decay of its daughter 106Rh, in gamma-ray spectra : Technical considerations for laboratory work

This report gives a brief overview of some key aspects to consider when searching for 106Ru in gamma-ray spectra from environmental samples and what to keep in mind when attempting to produce quantitative activity-results in the unit Bq.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

GERDA: a Germanium Detector Array to Search for Neutrinoless Double Beta Decay

The GERDA, a new experiment to search for the double beta decay of 76 Ge, is being installed at Laboratori Nazionali del Gran Sasso. The potentialities of this experiment as well as the status of the project are reviewed.JRC.D.4-Isotope measurement

Underground Measurements of Environmentala Radioactivity : European Examples

Scedule:17-18 March 2003, Vemue: Kanazawa, Japan, Kanazawa Citymonde Hotel, Project Leader : Hayakawa, Kazuichi, Symposium Secretariat: XO kamata, Naoto, Edited by:Kamata, Naoto

Quantification of uranium-238 in environmental samples using gamma-ray spectrometry

A large number of environmental samples are routinely measured world-wide using gamma-ray spectrometry some of its assets being easy sample preparation and comprehensive data for many radionu-clides in one analysis. Although other techniques can be considered more suitable for analysing 238U in environmental samples, it is also routinely done by gamma-ray spectrometry. One mainly uses γ-ray emissions following the decay of the first daughter, 234Th, for determining the 238U activity. However, the low-energy gamma-rays at 63 keV and 92.5 keV are very difficult to quantify in a robust way due to high attenuation and interferences. This paper quantifies parameters affecting the possibility of making robust quantification of 238U via 234Th using gamma-ray spectrometry. It addresses the use of correct decay data, suitable detectors, optimised sample size, enhanced spectral amplification, correction for peak interferences and control of background.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

On the Underground Production of High Purity Germanium Detectors

Detectors based on high purity germanium (HPGe) are used in numerous deep underground experiments world-wide aiming at detecting rare events like double beta decay and interactions of dark matter. These detectors require the lowest possible background. A significant part of the background is due to radionuclides produced by cosmic-ray interactions with the germanium crystal. This report gives quantitative data on this activation and discusses the possible solutions. The first solution is to optimise the logistics during the crystal and detector fabrication so that the germanium spends a minimum time above ground. The second solution is to implement one or several (up to 12) production steps underground. The report also makes estimates on the future needs for germanium produced underground and the costs involved.JRC.D.4-Isotope measurement

Radioactivity monitoring: How the JRC verifies results from monitoring within the European Union

This report provides a brief introduction to Proficiency Tests (PTs) and how they are used to make sure EU citizens are better protected from harmful levels of radioactivity, in support of Euratom Treaty Articles 35 and 36. the ten PTs organised by JRC-Geel in the past 15 years are summarized. The main conclusions from these PTs are stated and suggestions for improvements are presented.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Workshop for the participants in the 2017 EC Proficiency Test & Basic and advanced courses on gamma-ray spectrometry

Follow-up workshop and training for practitioners in gamma-ray spectrometry and laboratories that participated in the European ILC on radioactivity in maize.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard