Science and Technology Facility Council

United Kingdom

Science and Technology Facility Council

United Kingdom
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Raspino D.,Science and Technology Facility Council | Rhodes N.J.,Science and Technology Facility Council | Schooneveld E.M.,Science and Technology Facility Council
2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015 | Year: 2015

LET is a direct geometry cold neutron spectrometer at the ISIS spallation neutron source, working in the range between 0.5 and 30 meV (1.6 to 12.8 Å). The development and installation of a large area neutron detector array for LET has recently been completed. The detector array consists of 384 3He filled resistive wire tubes, 4 m long and 25.4 mm in diameter. The 3He pressure is 10 bars, to guarantee an efficiency above 90% for 1.6 Å neutrons, and 3 bars of argon are added as a stopping gas. The tubes are organized in twelve panels installed inside the LET vacuum tank that is operated at cryogenic vacuum. Here we will report about the rigorous assembly and test program of the detectors before their installation on the instrument and their performance on LET. The two main tasks in the assembly of the detectors were: aligning the support of the tubes with a precision better than 0.5 mm along the 4 m length of the tubes and guaranteeing the vacuum tightness for all the ∼2000 vacuum feeds-through. We will outline the methods used to achieve these goals and the tests performed to check these requirements before the installation of the detectors on the instrument. Regarding the operation of these detectors on LET, we will describe the digitization and processing of the signals from the tubes. In particular we will focus the attention on how the signal processing is optimized to operate these detectors at high neutron rates whilst preserving other performances like gamma rejection and position resolution. © 2015 IEEE.

Grazzi F.,National Research Council Italy | Bartoli L.,National Research Council Italy | Civita F.,Museo Stibbert | Franci R.,Museo Stibbert | And 3 more authors.
Journal of Analytical Atomic Spectrometry | Year: 2011

Japanese blades have always been considered very interesting objects, both from the stylistic point of view and their peculiar performances. It is amazing how the test and try process with a semi-empirical approach which lead to the optimization of Japanese blades, an almost ideal tool, is yet to be fully understood. In this work, we present results from a new non invasive approach to the study of these peculiar artefacts. Time of Flight Thermal Neutron Diffraction (TOF-ND) measurements were taken on two instrument INES and ENGIN-X, at the ISIS facility, RAL, UK. Two Japanese blades and eight blade fragments have been successfully characterized in terms of composition of the steel, smelting and smithing processes, and forging techniques. The differences among the production periods and forging traditions have been clearly determined. Further work is needed on standards to fully understand the production technique of a sample by comparison of the object under study with objects of known production methods. © 2011 The Royal Society of Chemistry.

Grazzi F.,National Research Council Italy | Bartoli L.,National Research Council Italy | Barzagli E.,National Research Council Italy | Civita F.,Museo Stibbert | And 3 more authors.
Metallurgia Italiana | Year: 2011

Two Japanese long blades of the Ancient Sword (Koto) age have been analysed through time of flight neutron diffraction. This technique allows the determination of several microstructural properties on different size gauge volumes. The results of the experiment provided a quantitative multiphase characterization of the steel composition of the blades and the determination of peculiar properties of the material, such as the texture, the strain level and the grain size of the crystallites.

Grazzi F.,CNR Institute for Complex Systems | Barzagli E.,CNR Institute for Complex Systems | Scherillo A.,Science and Technology Facility Council | De Francesco A.,CNR Institute of Materials | And 3 more authors.
Microchemical Journal | Year: 2016

The analysis of the micro-structural features of ancient Indian swords has been carried out by neutron diffraction as well as by metallography. The results provide a clear identification of the different materials used to produce those weapons. Only a small proportion of the large number of swords produced in India historically were made of hypereutectoid textured steel, namely wootz steel also (misleadingly) known as "Damascus steel". Diffraction analysis was applied to a group of four swords and the micro-structural and compositional characteristics were identified for all of them revealing a strongly differentiated construction method and the peculiar micro-structural features of at least one kind of wootz steel. This kind of result is a further proof of the validity of the use of neutron scattering techniques for authentication and characterization of ancient metal artefacts. © 2015 Elsevier B.V.

Pietropaolo A.,National Research Council Italy | Pietropaolo A.,ENEA | Murtas F.,National Institute of Nuclear Physics, Italy | Claps G.,National Institute of Nuclear Physics, Italy | And 6 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2013

A thermal neutron detector based on the Gas Electron Multiplier technology is presented. It is configured to let a neutron beam interact with a series of borated glass layers placed in sequence along the neutron path inside the device. The detector has been tested on beam both at the ISIS (UK) spallation neutron source and at the TRIGA reactor of ENEA, at the Casaccia Research Center, near Rome in Italy. For a complete characterization and description of the physical mechanism underlying the detector operation, several Monte Carlo simulations were performed using both Fluka and Geant4 code. These simulations are intended to help in seeking the optimal geometrical set-up and material thickness (converter layer, gas gap, sheet substrate) to improve the final detector design in terms of achieving the best detector efficiency possible. © 2013 Elsevier B.V.

Fuschino F.,National institute for astrophysics | Fuschino F.,National Institute of Nuclear Physics, Italy | Gabrielli A.,National Institute of Nuclear Physics, Italy | Gabrielli A.,University of Bologna | And 8 more authors.
Journal of Instrumentation | Year: 2014

The aim of the paper is to illustrate the design and the performance of a microelectronic circuit composed of a dosimeter, an oscillator, a modulator, a transmitter and an antenna. The device was designed for specific in vivo dosimetry applications. However, the layout area of less than 1 mm2 makes it suitable for a large variety of applications, from spot radiation monitoring systems in medicine to accurate measurements of radiation level in high-energy physics experiments. Moreover, due to its extremely low-power budget, it might be also of interest for space applications. The chip embeds a re-programmable floating-gate transistor configured as a radiation sensor and a read-out circuit. Prototype chips have been fabricated and tested exploiting a commercial 180 nm, four-metal CMOS technology. Characterization tests of the performance of the Ultra-Wide Band transmission are summarized. The dosimeter prototype has an estimated sensitivity of 1 mV/rad within a total absorbed dose range up to 10 krad. The read-out circuit is powered with 3.3 V and the total power consumption is very low, i.e. about 165 μW, making it also upgradable with a remote power system. © 2014 IOP Publishing Ltd and Sissa Medialab srl.

Fedrigo A.,CNR Institute for Complex Systems | Fedrigo A.,Copenhagen University | Grazzi F.,CNR Institute for Complex Systems | Williams A.,Wallace Collection | And 2 more authors.
Journal of Analytical Atomic Spectrometry | Year: 2015

Neutron Diffraction represents the ideal technique for the characterisation of the micro-structural properties of ancient metals, allowing retrieval of information on the smelting process, and the mechanical and thermal treatments applied during the manufacture of the sample. The object under investigation is a 17th century Japanese helmet (kabuto) from the Haruta School that has already been analysed, along with other six similar examples, using a general purpose neutron diffractometer. Through this study, the quality of the steel (phase composition) was determined and information on the thermo-mechanical treatments applied was inferred, averaging over a scattering volume that affected the entire thickness of the sample. The Haruta kabuto stood out for its very high carbon content, the absence of texture and residual strain, and very big grain size. These factors and the presence of incomplete reduction of the ore sand suggest the presence of plates with a composite structure of layers of steel and iron superimposed. This paper shows the possibility of using neutron diffraction on a highly collimated instrument, such as ENGIN-X (ISIS, UK), to be able to select a very small gauge volume and, this way, to detect variations in the phase composition along the thickness of the plates. Here we present novel results from diffraction measurements by using the instrument ENGIN-X. This study completes the previous cycle of neutron measurements on this sample and sheds light on the structure of the plates. © 2015 The Royal Society of Chemistry.

Breda M.,University of Padua | Brunelli K.,University of Padua | Grazzi F.,CNR Institute for Complex Systems | Scherillo A.,Science and Technology Facility Council | Calliari I.,University of Padua
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2014

Duplex stainless steels (DSSs) are biphasic steels having a ferritic-austenitic microstructure that allows them to combine good mechanical and corrosion-resistance properties. However, these steels are sensitive to microstructural modifications, such as ferrite decomposition at high temperatures and the possibility of strain-induced martensite (SIM) formation from cold-worked austenite, which can significantly alter their interesting features. In the present work, the effects of cold rolling on the developed microstructural features in a cold-rolled SAF 2205 DSS and the onset of martensitic transformation are discussed. The material was deformed at room temperature from 3 to 85 pct thickness reduction, and several characterization techniques (scanning and transmission electron microscopy, X-ray diffraction, hardness measurements, and time-of-flight-neutron diffraction) were employed in order to fully describe the microstructural behavior of the steel. Despite the low stacking fault energy of DSS austenite, which contributed to SIM formation, the steel was found to be more stable than other stainless steel grades, such as AISI 304L. Rolling textures were similar to those pertaining to single-phase materials, but the presence of the biphasic (Duplex) microstructure imposed deformation constraints that affected the developed microstructural features, owing to phases interactions. Moreover, even if an intensification of the strain field in austenite was revealed, retarded SIM transformation kinetics and lower martensite amounts with respect to AISI 304L were observed. © 2014, The Minerals, Metals & Materials Society and ASM International.

Grazzi F.,National Research Council Italy | Bartoli L.,National Research Council Italy | Civita F.,Stibbert Museum | Paradowska A.M.,Science and Technology Facility Council | And 2 more authors.
Materials Science Forum | Year: 2010

Two Japanese long swords (katanas) belonging to the Koto Age (X-XVI century A.D.) were measured through time of flight neutron diffraction to analyze the phases, and the stress and strain distribution, in selected parts of the blades. The swords are representative of two different forging schools (Aoe and Kanesada) and one of the main aims of the measurements was to evidence possible similarities and differences. Two independent experiments were carried out at the ISIS pulsed neutron source using the INES and ENGIN-X diffractometers. The former was employed to map the average phase distribution on two selected cross sections, of each blade, distinguishing among the ridge, the core, and the edge of the blades. In this way, we were able to quantify the coarse distribution of the carbon content and, moreover, we could evidence the presence of martensite. These data were then complemented measuring detailed stress and strain distribution maps on ENGIN-X. As far as the ridge and the core are concerned, the tang data were taken as a reference. These measurements significantly improve the knowledge and understanding of the technology used to produce Japanese swords belonging to the Koto Age. © (2010) Trans Tech Publications.

Albani M.,European Space Agency | Marelli F.,European Space Agency | Giaretta D.,Alliance for Permanent Access | Shaon A.,Science and Technology Facility Council
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2012

The proper preservation of both the current and historical scientific data will underpin a multitude of ecological, economic and political decisions in the future of our society. The SCIDIP-ES project addresses the long-term persistent storage, access and management needs of scientific data by providing preservation infrastructure services. Taking exemplars from the Earth Science domain we highlight the key preservation challenges and barriers to be overcome by the SCIDIP-ES infrastructure. SCIDIP-ES augments existing science data e-infrastructures by adding specific services and toolkits, which implement core preservation concepts, thus guaranteeing the long-term access to data assets across and beyond their designated communities. © 2012 IEEE.

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