P.G. Pelfer

Detection properties of LEC SI GaAs radiation detectors with the symmetrical contact configuration

Abstract I–V characteristics and detection properties (CCE, FWHM) of the semi-insulating GaAs detectors (base length 200 μm) with the Au-Au and W-W Schottky barriers and N + -N + ohmic contacts, measured at room temperature, are presented for α , β and heavier particles (up to Z ⋍ 10). The best results (average values of CCE and FWHM were 87% and 5%, respectively, for 5.48 MeV α particles from 241 Am) give detectors with the Au-Au contact configuration. Detectors with the N + contacts have worse parameters, about 30% for both, the CCE and FWHM, respectively. Nevertheless, such detectors operate at a low bias voltage, under 20 V.

GaAs detectors for hard X-ray astronomy

Particle detectors fabricated from bulk semi-insulating (SI) GaAs of 4 different suppliers are investigated. I-V, C-V characteristics, material transport parameters as well as inhomogeneities are studied and correlated with detector performances. It was observed that the charge collection efficiency and the energy resolution of detectors tested by 5.48 MeV α-particles and 122 keV X-rays is strongly affected by physical properties of the base material. It is concluded that detectors fabricated from the graded bulk SI GaAs material are suitable for application in hard X-ray astronomy.

ArchaeoGRID, a GRID for archaeology

The approach of modern archaeology to the study of the evolution of ancient human societies is based on the acquisition and analysis of many types of data. It is well known that in archaeology large use is done of digital technologies and computer applications for data acquisition, storage, analysis and visualization. The amount of information coming from remote sensing, from acquisition of 3D artifacts images by scanners laser, from GPS precise reference of geographical points and from other sciences are increasing at a large extent the amount of data that it need to be stored and made available for analysis. Such data must, however, be analyzed if they are to become valuable information and knowledge. The data analysis use advanced methods developed in mathematics, informatics, and physics and in other natural and human sciences. Moreover the use of virtual archaeology as a new approach to the narration and visualization in archaeology, is expanding rapidly, not only in the museum and archaeology professions, but also in the broadcast media, tourism and heritage industries. The inevitable result of this is an exponential increase of the amount and complexity of information that must be acquired, transferred, stored, processed and analyzed. From another side natural disasters, wars and terrorism created enormous damages to the archaeological heritage and in many case destroyed definitively all information about ancient civilizations. It is urgent a long term project for acquiring at least the archaeological information.

From WEB to GRID, a new perspective for archaeology

It is well known that in Archaeology large use is done of digital technologies and computer applications for data acquisition, storage, analysis and visualisation. In the last years the amount of information coming from remote sensing. from precise and fast acquisition of 3-D artefacts images by scanners laser, from GPS precise reference of geographical points and from other human and natural sciences are increasing at a large extent the amount of data that it need to be stored and made available for analysis. Moreover the use of Virtual Archaeology as a new approach to the narration and visualisation in Archaeology, is expanding rapidly, not only in the museum and archaeology professions, but also in the broadcast media, tourism and heritage industries. From another side recent natural and social disasters (wars) created enormous damages to the archaeological heritage and in many case destroyed definitively any information about ancient civilisations. It is urgent a longterm project for saving archaeological information for the present and next generations. The GRID technology developed by the CERN for the next experiments at LHC can be used for such project. The paper try to show what can be used by the present GRID technology and what could he modified to approach the specificity of the archaeological.

The semi-insulating GaAs-based particle detector at IEE SAS: first imaging results ☆

Abstract A particle detector made of semi-insulating GaAs is used for preliminary study of X-ray imaging. A standard technology developed in our laboratory is applied to prepare this detector. The detector works at room temperature in the photon counting mode. Results show that the quality of images taken at chosen exposure range is limited only by the photonic noise from used X-ray source 241 Am.

Semi-Insulating InP Particle Detectors For X- And γ-Ray Detection

A study of electrical properties and detection performances of the semi-insulating (SI) InP based detectors is presented. Detectors with a top P{sup +} layer and a Schottky back contact give the charge collection efficiency about 90% and an energy resolution 3.7% (FWHM) for 5.48 MeV {alpha}-particles at 250 K. Detection of X-rays (122 keV and 60 keV) photons in temperature region 220--250 K is demonstrated. Multiple peaking observed during detection of photons is discussed.

Role of physical parameters of bulk semi-insulating GaAs in detection performance of particle detectors

Study of bulk semi-insulating GaAs by the conductivity, Hall, GDMS, I-V and C-V techniques was used for material and detector characterisation. Detection performances of detectors have been tested using /sup 57/Co source of 122 keV gamma rays. Correlation between the physical properties of based material and performance of detectors is presented and discussed.

On the electrical and detection performances of particle detectors based on bulk semi-insulating InP

A study of electrical transport and detection performances of the bulk semi-insulating InP-based detectors of charged particles and /spl gamma/ rays is presented. The best detectors give a charge collection efficiency over 90% and energy resolution about 3% (FWHM) for 5.48 MeV /spl alpha/-particles and an energy resolution about 7% (FWHM) for 122 keV /spl gamma/-rays at 220 K. Detection performances versus temperature, contact systems and bias voltage polarity have been discussed.

The INFN Eloisatron Project: European Long Intersecting Storage Accelerator

Past experience, present knowledge, and a straightforward forecast in the extreme energy limits for subnuclear physics are reviewed, in order to put forward the case for a multi — TeV intersecting hadronic machine, whose basic features are described.