Search results for " X-ray spectroscopy"
showing 10 items of 42 documents
Hard X-Ray Response of Pixellated CdZnTe Detectors
2009
In recent years, the development of cadmium zinc telluride (CdZnTe) detectors for x-ray and gamma ray spectrometry has grown rapidly. The good room temperature performance and the high spatial resolution of pixellated CdZnTe detectors make them very attractive in space-borne x-ray astronomy, mainly as focal plane detectors for the new generation of hard x-ray focusing telescopes. In this work, we investigated on the spectroscopic performance of two pixellated CdZnTe detectors coupled with a custom low noise and low power readout application specific integrated circuit (ASIC). The detectors (10x10x1 and 10x10x2 mm3 single crystals) have an anode layout based on an array of 256 pixels with a …
Synthesis and thermoelectric characterisation of bismuth nanoparticles
2009
An effective method of preparation of bismuth nanopowders by thermal decomposition of bismuth dodecyl-mercaptide Bi(SC12H25)3 and preliminary results on their thermoelectric properties are reported. The thermolysis process leads to Bi nanoparticles due to the efficient capping agent effect of the dodecyl-disulfide by-product, which strongly bonds the surface of the Bi clusters, preventing their aggregation and significantly reducing their growth rate. The structure and morphology of the thermolysis products were investigated by differential scanning calorimetry, thermogravimetry, X-ray diffractometry, 1H nuclear magnetic resonance spectroscopy, scanning electron microscopy, and energy dispe…
Microwave-induced electromigration in multicomponent metallic alloys
2010
The crystallization of amorphous FeCoCuZrAlSiB alloy ribbons during microwave heating was investigated in situ using time-resolved X-ray powder diffraction. The formation of the nanocrystalline α-(Fe,Co)(SiAl) phase during the primary crystallization stage is followed by the crystallization of the residual glassy matrix. Scanning electron microscopy analysis after microwave exposure reveals the formation of nanosized hillocks evenly distributed over the ribbon surfaces. Local chemical composition analysis by energy-dispersive spectroscopy shows that the surface clusters are enriched in Cu and Al. The occurrence of this typical electromigration effect imposes a strong restriction on the dura…
Characterization of Iranian Moarraque glazes by light microscopy, SEM-EDX and voltammetry of microparticles
2008
Abstract Glazed ceramics have been traditionally used in Iran for decorating mosques and some civil historical buildings. In particular, Moarraque glazes have been extensively used in the indoor and outdoor decoration of mosques in Iran since the middle 14th century. The pieces have a complex elaboration based on a main glazed piece corresponding to the skeleton structure of the Shah Abbasi flower, which contains a number of holes, where are placed, mosaic-like, smaller glazed pieces forming a compact and single tile. The present work describes the analytical study performed on the glazes of several pieces of Moarraque tiles from the Ali Ebn Abi Taleb Mosque (Esfahan, Iran), which date back…
Performance of a digital CdTe X-ray spectrometer in low and high counting rate environment
2010
Abstract The high performances of CdTe detectors for X-ray and gamma ray spectroscopy are already well known. Among the traditional semiconductor spectrometers, CdTe detectors show high detection efficiency and good room temperature performance and are well suited for the development of compact detection systems. In this work, we investigated the performance of a CdTe detector coupled with a custom digital pulse processing (DPP) system for X-ray spectroscopy. The DPP method, implemented on a PC platform, performs a pile-up inspection and a pulse height analysis of the preamplifier output pulses, digitized by a 14-bit, 100 MHz ADC. The spectroscopic results point out the excellent performanc…
Characterization of prehispanic cosmetics found in a burial of the ancient city of Teotihuacan (Mexico)
2012
The present paper reports the chemical data obtained on samples of pigmenting materials contained in 31 miniature vessels found in a burial found in Teopancazco, a multiethnic neighborhood center located in the southeastern sector of the archaeological site of Teotihuacan (Central Mexico) and the analytical protocol established for the complete characterization of these archaeological materials. For this purpose a multi-technique approach based on the combination of several non destructive and micro-destructive instrumental techniques, namely, light microscopy (LM), scanning electron microscopy-X-ray micro-analysis (SEMe EDX), transmission electron microscopy (TEM), voltammetry of micropart…
The Athena X-ray Integral Field Unit (X-IFU)
2016
Event: SPIE Astronomical Telescopes + Instrumentation, 2016, Edinburgh, United Kingdom.
Citocentrifugación como un método adicional para estudiar celomitos de equinodermos: un enfoque comparativo que combina células vivas, preparaciones …
2021
Abstract Introduction: Echinoderm coelomocytes have traditionally been investigated through a morphological approach using light microscopy, which relies on the idea of constant cell shape as a stable character. However, this can be affected by biotic or abiotic conditions. Objective: To analyze if the consistency in cell morphology offered by the cytocentrifugation method, might be used as a convenient tool to study echinoderm coelomocytes. Methods: Cells of Echinaster (Othilia) brasiliensis (Asteroidea), Holothuria (Holothuria) tubulosa (Holothuroidea), Eucidaris tribuloides, Arbacia lixula, Lytechinus variegatus, and Echinometra lucunter (Echinoidea) were spread on microscope slides by c…
Micromorphological approach to the systematics of Mediterranean Isoëtes species (Isoëtaceae, Lycopodiophyta): analysis of the megaspore surface
2012
Megaspore ornamentation is one of the few morphological characters used in the taxonomy of the genus Isoëtes. In the present work, we test the application of this character for distinguishing some Isoëtes species occurring in the Mediterranean: Isoëtes sicula, which according to some authors should be included as a variety in I. histrix, and the recently described I. todaroana, whose affinity with other taxa is currently unknown. Two additional species (I. duriei, I. velata) were also included in the analysis. The megaspores were studied using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and chemical treatment. In all species, the megaspore surface is cove…
Direct laser welding of pure titanium to austenitic stainless steel
2018
Abstract Direct butt joining of pure titanium to 316L stainless steel with continuous Yb:YAG laser was performed with variation of the beam offset from joint line. Mechanical properties of samples were evaluated by tensile tests and three-point flexural tests. The fractured surfaces and cross sections of welds were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Tensile properties of welds were strongly determined by the beam offset from joint line and are well described by Weibull statistics. Ultimate tensile strength of 174 ± 69 MPa and ultimate flexural strength of 297 ± 48 MPa were obtained. Brittle fracture took place in…