Present position: Hardware Engineer
|Thesis title:||Development of instrumentation for material analysis by means of X-ray analytical techniques|
|Research area:||Sensors and Instrumentation|
This dissertation concerns the development of advanced instrumentation for non-destructive material analysis based on the spectroscopic analysis of the X-ray radiation emitted from properly excited samples. In particular the instrumentation is optimized for “elemental mapping” measurements. The instrumentation is based on SDD (Silicon Drift Detector). Depending on application the instrumentation can be coupled with single SDD or with innovative topologies of array of SDD’s. For applications demanding high spatial resolution suitable optics for the primary or secondary X-ray radiation focalization is used.
The activity carried out concerns the study and the characterization of the detector and the development of the main components of the spectroscopy system, like: automatic polarization system for the detectors, very low noise preamplifier based on the pulsed-reset technique, analogue shaping filter and the data acquisition system for the signals coming from a single or matrix of the detectors. The system to control all the measuring process and data analysis is also provided.
Provided spectroscopy instrumentation can be considered as a unique spectroscope, however each particular component of the system can be used separately depending on the requirements. The spectroscopy instrumentation is characterized with high energy resolution, stable energy resolution over a wide range of incoming radiation rates, very low peak shift with respect to incoming radiation rates, high spatial resolution (typically few tens of micrometers or less), and high data acquisition throughput.
The major part of activity was carried out in the framework of experiments of INFN (Istituto Nazionale di Fisica Nucleare) to which I was associated since the beginning of my PhD activity. In particular the first year work has been carried out under the FELIX (Fast ELement Imaging with X-ray spectroscopy) experiment that is now concluded. Starting from 2006 I participated to a new experiment DRUIDNORMA (DRUgs delivery Image Detection with NOn-Radioactive Markers) that derives from FELIX. The experiment took place at ELETTRA TRIESTE synchrotron at the SYRMEP and TWINMIC beamlines. A set of X-ray measurements concerning elemental mapping of biologic samples using the synchrotron light has been performed in the frame of the cooperation with SYRMEP beamline group. In particular, the study of the drugs distribution and diagnostic agents in organs like liver and spleen by means of XRF (X-ray fluorescence) detected with SDD took place. At the TWINMIC beamline (X-ray microscope) the development of XRF spectrometer is being carried out with the aim to perform elemental mapping at the level of biological cells. The foreseen instrumentation will be able to perform sample scanning with submicrometer spatial resolution. The preliminary tests and measurements have been performed providing promising results.
Another field of activity was participation to a new INFN experiment DANTE (Development of Analitycal Nuclear TEchniques) mainly intended to apply novel developments in the detection systems and electronics to material analysis. The activity concerned development of a fully operative detection system, based on Silicon Drift Detectors, to be used in a Particle-induced X-ray emission (PIXE) setup at the LABEC (Laboratorio di Tecniche Nucleari per i Beni Culturali) in Firenze.
Since the beginning, my PhD activity was intended to investigate different fields with the aim of exploiting the potential of XRF and PIXE techniques and testing the possibility of innovative developments of the high performance spectroscopy instrumentation. As a matter of fact this has been tested and used in mentioned science experiments providing good results. In general the developed spectroscopy system can be further used in the field of elemental analysis by interested science and industry units.
This work reports the most significant results of all my activity during the last three years. In Chapter 1, the main features of elemental analysis techniques and general overview of the spectroscopy instrumentation are briefly recalled. Chapter 2 introduces the development of the front-end electronics part of the system, while in Chapter 3 the development of the back-end part is reported. In Chapter 4 the applications of the developed instrumentation are reported.