Results of high frequency modulated photocurrent spectroscopy (HF MPC) performed on epitaxial and polycrystalline CuGaSe2 thin films are presented. Frequency and temperature scans of MPC in the high ...frequency regime are compared, and the advantages of the second mode of measurement over the first one are demonstrated. Electronic parameters of defect levels in Cu-rich and Ga-rich stoichiometry are obtained and discussed in comparison to the literature data on defect levels derived from capacitance junction techniques. An attempt to correlate levels observed by MPC technique with material stoichiometry has been made.
Results of high frequency modulated photocurrent spectroscopy (HF MPC) performed on epitaxial and polycrystalline CuGaSe
2 thin films are presented. Frequency and temperature scans of MPC in the high ...frequency regime are compared, and the advantages of the second mode of measurement over the first one are demonstrated. Electronic parameters of defect levels in Cu-rich and Ga-rich stoichiometry are obtained and discussed in comparison to the literature data on defect levels derived from capacitance junction techniques. An attempt to correlate levels observed by MPC technique with material stoichiometry has been made.
This report summarises the final results obtained by the RD48 collaboration. The emphasis is on the more practical aspects directly relevant for LHC applications. The report is based on the ...comprehensive survey given in the 1999 status report (RD48 3rd Status Report, CERN/LHCC 2000-009, December 1999), a recent conference report (Lindström et al. (RD48), and some latest experimental results. Additional data have been reported in the last ROSE workshop (5th ROSE workshop, CERN, CERN/LEB 2000-005). A compilation of all RD48 internal reports and a full publication list can be found on the RD48 homepage (http://cern.ch/RD48/). The success of the oxygen enrichment of FZ-silicon as a highly powerful defect engineering technique and its optimisation with various commercial manufacturers are reported. The focus is on the changes of the effective doping concentration (depletion voltage). The RD48 model for the dependence of radiation effects on fluence, temperature and operational time is verified; projections to operational scenarios for main LHC experiments demonstrate vital benefits. Progress in the microscopic understanding of damage effects as well as the application of defect kinetics models and device modelling for the prediction of the macroscopic behaviour has also been achieved but will not be covered in detail.
Data taken during half a year of operation of 10 LOPES antennas (LOPES-10), triggered by EAS observed with KASCADE-Grande have been analysed. We report about the analysis of correlations of radio ...signals measured by LOPES-10 with extensive air shower events reconstructed by KASCADE-Grande, including shower cores at large distances. The efficiency of detecting radio signals induced by air showers up to distances of 700m from the shower axis has been investigated. The results are discussed with special emphasis on the effects of the reconstruction accuracy for shower core and arrival direction on the coherence of the measured radio signal. In addition, the correlations of the radio pulse amplitude with the primary cosmic ray energy and with the lateral distance from the shower core are studied.
Radiation-hard semiconductor detectors for SuperLHC Bruzzi, M.; Alfieri, G.; Assouak, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2005, Letnik:
541, Številka:
1
Journal Article
Recenzirano
An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 10
35
cm
−2
s
−1 has been envisaged to extend the physics reach of the machine. An efficient tracking down to a ...few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the interaction region will receive severe doses of fast hadron irradiation and the inner tracker detectors will need to survive fast hadron fluences of up to above 10
16
cm
−2. The CERN-RD50 project “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” has been established in 2002 to explore detector materials and technologies that will allow to operate devices up to, or beyond, this limit.
The strategies followed by RD50 to enhance the radiation tolerance include the development of new or defect engineered detector materials (SiC, GaN, Czochralski and epitaxial silicon, oxygen enriched Float Zone silicon), the improvement of present detector designs and the understanding of the microscopic defects causing the degradation of the irradiated detectors. The latest advancements within the RD50 collaboration on radiation hard semiconductor detectors will be reviewed and discussed in this work.
The envisaged upgrade of the Large Hadron Collider (LHC) at CERN towards the Super-LHC (SLHC) with a 10 times increased luminosity of 10
35
cm
−2
s
−1 will present severe challenges for the tracking ...detectors of the SLHC experiments. Unprecedented high radiation levels and track densities and a reduced bunch crossing time in the order of 10
ns as well as the need for cost effective detectors have called for an intensive R&D program. The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” is working on the development of semiconductor sensors matching the requirements of the SLHC. Sensors based on defect engineered silicon like Czochralski, epitaxial and oxygen enriched silicon have been developed. With 3D, Semi-3D and thin detectors new detector concepts have been evaluated and a study on the use of standard and oxygen enriched p-type silicon detectors revealed a promising approach for radiation tolerant cost effective devices. These and other most recent advancements of the RD50 collaboration are presented.
The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN will demand the innermost layers of the vertex detectors to sustain fluences of about 10
16 hadrons/cm
2. Due to the high ...multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field new detector concepts and semiconductor materials have to be explored for a possible solution of this challenge. The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” has started in 2002 an R&D program for the development of detector technologies that will fulfill the requirements of the S-LHC. Different strategies are followed by RD50 to improve the radiation tolerance. These include the development of defect engineered silicon like Czochralski, epitaxial and oxygen-enriched silicon and of other semiconductor materials like SiC and GaN as well as extensive studies of the microscopic defects responsible for the degradation of irradiated sensors. Further, with 3D, Semi-3D and thin devices new detector concepts have been evaluated. These and other recent advancements of the RD50 collaboration are presented and discussed.
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