Comportamiento térmico del Zr02 nanoestructurado después de su irradiación con iones pesados

Diferentes probetas nanocristalinas de ZrO2 se prepararon mediante la tecnología de condensación de gas inerte y sinterizadas a altas temperaturas. Las probetas se irradiaron posteriormente con iones, de Kr+ (Kript6n) con energía de 4 MeV y dosis de 2* 1015 iones/cm2 hasta 2*1016 iones/cm2. Se pudo observar, en dependencia de la dosis de irradiación, una transformación de la fase monoclínica a la tetragonal, utilizando la tecnología de Difracción de Rayos X. Las muestras se calentaron seguidamente hasta temperaturas de 1300oC, para lo cual , las muestras irradiadas con dosis de hasta 1*1016 iones/cm2 y más, presentaron una estructura tetragonal estable hasta 900°C, lo que está en concordancia con la temperatura de sinterización. A temperaturas mayores se pudo observar un contenido residual de la fase tetragonal menor que 5%. Un crecimiento del grano de ambas fases después de la irradiación no se pudo  observar

Ein Mühlstein als Abdeckung einer frühmittelalterlichen Grube aus Neunkirchen, NiederösterreichŽrmlje kot pokrov zgodnjesrednjeveške jame iz Neunkirchna, Niederösterreich

/A Quern as a Cover of an Early Mediaeval Pit from Neunkirchen, Lower Austria/On the outskirts of the cremation graves cemetery from Early Imperial period, many pits with pottery and animal bones were found, which could be the remains of funeral rites of that time. A real surprise was the discovery of an early mediaeval pit with pottery and animal bones that were covered with a useless quern. The complex of this pit cannot be linked with the original purpose of the quern stone. As similar examples from Lower Austria, Bohemia and Moravia show, the secondary position of the stone can be explained by Slavic mythology. Carefully made pottery and animal bones can indicate such use

Die Höhlenkirche im Burgberg von Pitten, NiederösterreichJamska cerkev v grajskem hribu v Pittnu, Spodnja Avstrija

Since approximately 1050, the cave church in the castle hill of Pitten had been used as a Christian parish church. Evidence supporting an old surmise that the cave had been used as a site for cultic ceremonies since prehistoric times has been discovered quite recently and the surmise can be corroborated at least for the periods of Hallstatt and Late Antiquity. In antiquity, the cave probably served as a Mitra temple, and in the High Middle Ages definitely functioned as a parish church. Containing frescoes painted in the Byzantine style, one of which depicts the birth of Christ, the church seems to be predestined for this very purpose

Comportamiento térmico del Zr02 nanoestructurado después de su irradiación con iones pesados

Diferentes probetas nanocristalinas de ZrO2 se prepararon mediante la tecnología de condensación de gas inerte y sinterizadas a altas temperaturas. Las probetas se irradiaron posteriormente con iones, de Kr+ (Kript6n) con energía de 4 MeV y dosis de 2* 1015 iones/cm2 hasta 2*1016 iones/cm2. Se pudo observar, en dependencia de la dosis de irradiación, una transformación de la fase monoclínica a la tetragonal, utilizando la tecnología de Difracción de Rayos X. Las muestras se calentaron seguidamente hasta temperaturas de 1300oC, para lo cual , las muestras irradiadas con dosis de hasta 1*1016 iones/cm2 y más, presentaron una estructura tetragonal estable hasta 900°C, lo que está en concordancia con la temperatura de sinterización. A temperaturas mayores se pudo observar un contenido residual de la fase tetragonal menor que 5%. Un crecimiento del grano de ambas fases después de la irradiación no se pudo  observar

Enhanced search methods for finding and identifying radioactive material for on-site inspection deployment

The CTBTO verification system comprises an On-Site Inspection (OSI) to verify the suspicion of a banned nuclear test. An OSI comprises different methods of verification, one of them being the radiological survey of the inspection area. The radiological survey is done by airborne survey, carborne survey, and environmental sampling, thereby narrowing the inspected area with each step. Our institute operates a measurement car DeGeN (German acronym for Detection of Gamma and Neutrons) with highly sensitive neutron and gamma detection systems. In the present study we investigated the influence of the human factor by investigating measurement results obtained by a larger group of test persons operating our measurement car DeGeN

Study of neutron detection technologies using ⁶Li as a replacement of ³He: Paper presented at INMM 2017, 58th Annual Meeting Institute of Nuclear Materials Management, July 2017, Indian Wells

Within the past decade a significant shortage of ³He has occurred. Since this material is widely used in neutron detection applications, e.g. by first responders, during on-site inspections, and in safeguard applications where nuclear and radioactive material has to be localized and possibly identified, replacement materials need to be considered, selected, implemented in a corresponding detector, and thoroughly tested. One of these promising materials is ⁶Li which is utilized in detector applications such as ⁶LiF/ZnS, CLYC (Cs₂LiYCl₆:Ce), and CLLB (Cs₂LiLaBr₆:Ce). The latter two detector types even offer the possibility of measuring gamma radiation simultaneously with good discrimination capability between neutrons and gammas. Within the detection materials neutrons are captured by ⁶Li, triggering the nuclear reaction ⁶Li(n,t)α. The secondary particles then create light pulses in the scintillation crystal which ultimately serve as detection signals. Due to the large Q-value of the reaction of 4.78 MeV, the signals are of the same order of magnitude as those of high energetic gamma photons. The discrimination of neutron and gamma radiation can be realized by pulse shape analysis. Measurements with all detector types mentioned above have been performed. We have verified these detectors’ capabilities with measurements of several neutron sources, also compared to a detector filled with ³He. The possibility of detecting such a (hidden and/or shielded) source which creates a radiation field only slightly above the background radiation level is of particular interest. Other figures of interest were the FWHM (full width at half maximum) of the CLYC and CLLB gamma spectra and the detectors’ efficiencies, especially with regard to a detector with ³He tubes. The results of these verification tests will serve as supportive information for first responders and other experts who work in the field of nuclear safety and security regarding suitable neutron detection materials without the rare ³He

DeGeN - Measurement vehicle for radioactive and nuclear material: Poster presented at 4th European IRPA Congress 2014, June 23rd to June 27th 2014, Geneva, Switzerland

The measurement system DeGeN comprises gamma and neutron detectors with high sensitivity suitable for detecting radioactive and nuclear (RN) material. Because of the high sensitivity, even minor changes of the natural background radiation can be registered which is tremendously important for the discrimination between the presence of actual RN material and mere modifications of the natural background. Knowledge about such a discrimination is absolutely necessary in order to be able to evaluate the measurement results correctly. Questionable results which could lead to wrong response measures are more likely to be prevented then

Radiation detection for OSI - A study of non-He-3 neutron detectors: Poster presented at CTBT: Science and Technology 2019 Conference, 24 to 28 June 2019, Vienna, Austria

Within the past decade a significant shortage of He-3 and consequently an enormous increase in cost has occurred. Detectors equipped with He-3 are widely used in neutron detection applications, e.g. by first responders, during on-site inspections, and in other applications where nuclear and radioactive material has to be detected, localized and possibly identified. Therefore replacement materials need to be considered, selected, implemented in corresponding detectors, and thoroughly tested. Another development in the field of hand-held radiation detection devices focuses on simultaneous neutron and gamma ray detection with a single scintillator. These may lead to a new type of small and efficient hand-held devices, utilizing non-He-3 neutron detection. The outcome of a study of the scintillators CLYC and CLLB which allow a simultaneous measurement of gamma and neutron radiation will be presented in this contribution. Additionally, results with a neutron detector implemented in a wearable Radiation Isotope Identifier Device (RIID), the D3S from Kromek, will be shown. Differences in the detection of neutron radiation will be explored and analyzed regarding their potential use in on-site inspections

CLYC scintillators: a possible enhancement for handheld OSI detectors

Many detection systems detect either gamma or neutron radiation or combine the detection of both nuclear radiation types byintegrating two detectors in one system. For hand-held systems a very small 3He-tube is often combined with a scintillation crystal of e.g. NaI or LaBr3. The recently developed detector material CLYC promises to detect gammas and neutrons simultaneously with good resolution and efficiency for fast and reliable isotope identification and efficient neutron counting. In the paper we report on tests with a CLYC detector. The scintillation material of CLYC-detectors (Cs2LiYCl6:Ce) contains enriched 6Li. Via the nuclear reaction 6Li(n,α)t alpha particles and high energetic tritons are generated by neutron radiation. The ions generate a light pulse while travelling through the crystal. Gamma radiation excites electrons in the scintillator. Neutron and gamma radiation have a unique pulse shape, enabling the distinct discrimination of induced pulses. New detector materials like CLYC, which are able to detect gammas and neutrons simultaneously, may lead to a new type of small and efficient hand-held devices. These detectors have the potential to improve the detection of nuclear and radioactive material and may be used successfully in OSI

Air-bound measurements of radioactive material with swarm-behaved UAVs - the ANCHORS project

In the project ANCHORS (UAV-Assisted Ad Hoc Networks for Crisis Management and Hostile Environment Sensing), a German-French consortium designs a system of UAVs (Unmanned Aerial Vehicles) which are partly equipped with sensors for detecting radioactive material and communicate by means of a self-sustained relay system. The UAVs are meant to operate in crisis areas inaccessible to human operators. Possible scenarios such an application would be suitable for are characterized by a considerably high level of danger for first responders, a limited access to a critical infrastructure because of a high degree of destruction, and limited communication options due to destroyed hardware. Such scenarios could be both man-made hazards such as an accident in a nuclear power plant and natural disasters. The system aims at fast and reliable exploration of a crisis scene including the localization and identification of potentially deposited radioactive material, thus leading to an appropriate crisis management. The project commenced in May 2012 and is scheduled to run for three years. It is funded by the Federal Ministry of Education and Research of Germany (BMBF) and the French National Research Agency (ANR). The Fraunhofer INT’s part of the consortium work includes support of the sensor development, measurements of the radiation hardness and electromagnetic compatibility (EMC) of the UAVs and the sensors as well as planning and realization of demonstration exercises of sensor measurements and the application of the entire system. A status report will be given, including first results of sensor measurements, radiation hardness measurements, and EMC measurements, all performed at Fraunhofer INT. The system components’ radiation hardness and EMC must be tested in order to assure that the system is operational under conditions which may come along with a crisis scenario, such as a high level of radioactivity. Moreover, a possible crisis scenario may require the system to work under the influence of an elevated electromagnetic field strength, and the sensors need to work reliably under these conditions. The sensor measurements will make use of the irradiation facilities at Fraunhofer INT, namely a Co-60 source emitting gamma radiation. A scenario where radioactive material is deployed can be recreated this way, thus proving the practicability of the measurement system for detecting such material at this point of the project