Identification of nuclear material with hand-held and portable gamma and neutron measuring devices

Performing fast measurements in the field at places where suspicious objects were found is essential in the context of nuclear terrorism. Especially if nuclear material is involved, it is necessary to identify small amounts of plutonium or uranium and to gain information concerning isotopic composition. Therefore, measurements at different uranium and plutonium samples were carried out. Samples with different isotopic compositions have been used for the present work. For gamma measurements hand-held and portable devices using different detector materials were investigated. The nuclide identification results of implemented automatic identification routines were compared for the different devices and to the given source information. As hand-held device with germanium detector (Ge) the ORTEC Micro Detective with electrical cooling was used. The identiFINDER from ICx was used as an example for an hand-held device and gamma-ray spectrometer with the most common detector material sodium iodide (NaI). Another investigated detection system was the InSpector 1000 from Canberra which contains a lanthanum bromide (LaBr3) crystal. A fourth type of detector material is used by the INTERCEPTOR from Thermo which is equipped with two cadmium-zinc-telluride (CZT) crystals. Some of the measurement devices also have neutron detectors but with very small volume and therefore low efficiency. A portable neutron detector with an implemented analysis routine for the discrimination between industrial and nuclear neutron sources is the Fission Meter from ORTEC. The paper presents results obtained with the different measurement systems. The quality of the outcome of the automatic identification routines of the different detection systems varied significantly. These results depended not only on the different detector materials but also on the type of nuclear material. In general identification of uranium was considerably better than the identification of plutonium

Spectroradiometry in PV: how inter-laboratory comparison may improve measurement accuracy

Spectroradiometry is a key metrological discipline for accurate testing of photovoltaic (PV) devices, particularly relevant both for indoor testing on solar simulators and for outdoor testing, where differences between the available thermal energy and the energy usable by PV modules are relevant. In fact, as to indoor testing, the uncertainty in the spectral mismatch between the testing light source and the reference spectral irradiance may give rise to deviations up to 1-3% when measuring the maximum power even on a Class A solar simulator. Experimental uncertainty is expected to increase even further after the publication of the new revision of IEC 60904-9 (“Solar simulator performance requirements”), which is due by 2018. As to outdoor testing, accurate knowledge of solar spectral irradiance is important also for energy rating purposes, in view of the publication of IEC 61853 part 3 (“Energy rating of PV modules”) and part 4 (“Standard reference climatic profiles”). The relevance of accurate measurements of solar spectral irradiance has led the most renowned accredited European solar PV test centres to take part to a series of International Spetroradiometer Intercomparisons that has taken place every year so far since 2011 in various localities in the Mediterranean Basin. The ever-growing number of participating laboratories is both a consequence and a key of success of the whole exercise: ISO 17025 accredited laboratories are willing to receive confirmation of the stability and accuracy of their spectroradiometers and that can be done only when a conspicuous number of testing centres is involved. This paper summarizes the outcomes of the last intercomparisons, trying to highlight whether improvements in measurement reproducibility can be inferred from those partners that have participated since the earliest editions. The work gives new insights into spectroradiometry for both outdoor and indoor testing applications.JRC.C.2-Energy Efficiency and Renewable