1,721,209 research outputs found
RADIOCARBON DATING: La spettrometria di massa con acceleratore al CEDAD
No full textIl DVD descrive il metodo del radiocarbonio e la spettrometria di massa con acceleratore sviluppatasi negli anni '80. Viene descritta la produzione del radiocarbonio mediante l'interazione dei raggi cosmici con l'atmosfera e il suo assorbimento negli organismi viventi. Vengono illustrate le variazion nella produzione di radiocarbonio per effetto dei fenumeni naturali(Variazione del campo magnetico terrestre, variazione dell'inetnsità dei raggi cosmici, ecc) e per gli effetti antropogenici (Bomb Peak e efftto Suess). Descrive i meccanismi fisici e chimici che poratno alla separazione e alla misura diretta degli isotopi del carbonio in acceleratori di tipo tandem
LASER INDUCED PHASE TRANSITIONS IN Si AND Ge IMPLANTED Si SUBSTRATES, phys. stat. sol. (a) 151, 23, (1995).
No full textE/Q and ME/Q2 contributions to machine background in sequential injection radiocarbon AMS
No full textEfficiency and instabilities of financial markets
Full text link[Excerpt from the abstract]: In this thesis, we consider two topics in the field of high frequency financial econometrics. The first one is the measurement of market efficiency from high frequency data, within an information theory framework. The study of this topic is performed with an analytical and empirical combined approach.
The second topic is that of financial market systemic instabilities at high frequency level and is analysed mainly with an empirical and modelling approach. [...
DEFECTS IN ION-IMPLANTED CRYSTALLINE SILICON PROBED BY FEMTOSECOND LASER SPECTROSCOPY, Il Nuovo Cimento 18, 1 (1997).
No full text
Radiocarbon dating by accelerator mass spectrometry: fundamentals and applications to archaeology
No full textHigh resolution radiocarbon dating of prehistoric sites in southern Italy
No full textA new facility for accelerator mass spectrometry radiocarbon
dating has been put in operation at the University of
Lecce in southern Italy. The general features of the facility are
described, showing how by the use of electrostatic andmagnetic
analyzers the radiocarbon content in several kinds of sample
materials can be measured. The performances of the system are
also given in terms of precision, accuracy and background. The
results of the radiocarbon dating of two prehistoric sites are also
reported
Studies of industrial emissions by accelerator-based techniques: a review of applications at CEDAD
No full textDifferent research activities are in progress at the Centre for Dating
and Diagnostics (CEDAD), University of Salento, in the field of
environmental monitoring by exploiting the potentialities given by the
different experimental beam lines implemented on the 3 MV Tandetron
accelerator and dedicated to AMS (Accelerator Mass Spectrometry)
radiocarbon dating and IBA (Ion Beam Analysis). An overview of
these activities is presented by showing how accelerator-based analytical
techniques can be a powerful tool for monitoring the anthropogenic
carbon dioxide emissions from industrial sources and for the assessment
of the biogenic content in SRF (Solid Recovered Fuel) burned in WTE
(Waste to Energy) plants
The influence of injection parameters on mass fractionation phenomena in radiocarbon analysis
No full textThree different possible sources of mass fractionation have been investigated in an accelerator mass spectrometer
system using sequential injection, namely: the influence of the accelerating/decelerating gaps in front of- and after the
bouncing magnet, the influence of changes in the ion trajectories for the three carbon isotopes during bouncing and
finally the influence of beam intensity. Measurements have indicated that the first two of these sources on the isotopic
ratios measurements can be neglected. On the other hand, it was demonstrated that increasing beam intensity influences
the 14C/12C ratio and to a lesser extent the 14C/13C ratio. This is probably related to space charge effects
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