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Ionel Lazanu

Publications and source records attributed to Ionel Lazanu.

30 records · Page 2Linked to original sources
arXiv2006

Correlation between radiation processes in silicon and long-time degradation of detectors for high energy physics experiments

In this contribution, the correlation between fundamental interaction processes induced by radiation in silicon and observable effects which limit the use of silicon detectors in high energy physics experiments is investigated in the frame of a phenomenological model which includes: generation of primary defects at irradiation starting from elementary interactions in silicon; kinetics of defects, effects at the p-n junction detector level. The effects due to irradiating particles (pions, protons, neutrons), to their flux, to the anisotropy of the threshold energy in silicon, to the impurity concentrations and resistivity of the starting material are investigated as time, fluence and temperature dependences of detector characteristics. The expected degradation of the electrical parameters of detectors in the complex hadron background fields at LHC & SLHC are predicted.

physics.ins-det↗
arXiv2006

Silicon detectors: damage, modelling and expected long-time behaviour in physics experiments at ultra high energy

In this contribution, the structural modifications of the material and the degradation of devices is modelled and compared with experimental data for more resistivities, temperatures, crystal orientations and oxygen concentrations, considering the existence of the new primary fourfold coordinated defect, besides the vacancy and the interstitial. Some estimations of the behaviour of detectors in concrete environments at the next generations of high energy physics experiments as LHC, SLHC, VLHC, or ULHC are done.

physics.ins-det↗
arXiv2006

Time dependence of the behaviour of silicon detectors in intense radiation fields and the role of primary point defects

The bulk displacement damage in the detector, produces effects at the device level that limits the long time utilisation of detectors as position sensitive devices and thus the lifetime of detector systems. So, the prediction of time behaviour of detectors in hostile radiation environments represents a very useful tool. In this contribution we predict the time degradation of silicon detectors in the radiation environments expected in the LHC machine upgrade in luminosity and energy as SLHC, for detectors fabricated from silicon crystals obtained by different growth technologies, in the frame of the model developed by the authors, and which takes into account the contribution of primary defects.

physics.ins-det↗
arXiv2006

An Analysis of the Expected Degradation of Silicon Detectors in the Future Ultra High Energy Facilities

In this contribution we discuss how to prepare some possible detectors - only silicon option being considered, for the new era of HEP challenges because the bulk displacement damage in the detector, consequence of irradiation, produces effects at the device level that limit their long time utilisation, increasing the leakage current and the depletion potential, eventually up to breakdown, and thus affecting the lifetime of detector systems. Physical phenomena that conduce to the degradation of the detector are analysed both at the material and device levels, and some predictions of the time degradation of silicon detectors in the radiation environments expected in the LHC machine upgrade in luminosity and energy as SLHC or VLHC, or at ULHC are given. Possible effects at the detector level after high energy cosmic proton bombardment are investigated as well. Time dependences of these device parameters are studied in conditions of continuous irradiation and the technological options for detector materials are discussed, to obtain devices harder to radiation.

physics.ins-det↗
arXiv2004

Scenarios about the long-time damage of silicon as material and detectors operating beyond LHC collider conditions

For the new hadron collider LHC and some of its updates in luminosity and energy, as SLHC and VLHC, the silicon detectors could represent an important option, especially for the tracking system and calorimetry. The main goal of this paper is to analyse the expected long-time degradation in the bulk of the silicon as material and for silicon detectors, in continuous radiation field, in these hostile conditions. The behaviour of silicon in relation to various scenarios for upgrade in energy and luminosity is discussed in the frame a phenomenological model developed previously by the authors. Different silicon material parameters resulting from different technologies are considered to evaluate what materials are harder to radiation and consequently could minimise the degradation of device parameters in conditions of continuous long time operation.

hep-ph↗
arXiv2003

Systematic study related to the role of initial impurities and irradiation rates in the formation and evolution of complex defects in silicon for detectors in HEP experiments

The influence of oxygen and carbon impurities on the concentrations of defects in silicon for detector uses, in complex fields of radiation, characteristic to high energy physics experiments, is investigated in the frame of the quantitative phenomenological model developed previously by the authors and extended in the present paper. Continuous irradiation conditions are considered, simulating realistically the environments for these experiments. The generation rate of primary defects is calculated starting from the projectile - silicon interaction and from the recoil energy redistribution in the lattice. The mechanisms of formation of complex defects are explicitly analysed. Vacancy-interstitial annihilation, interstitial and vacancy migration to sinks, divacancy, vacancy- and interstitial-impurity complex formation and decomposition are considered. Oxygen and carbon impurities present in silicon could monitor the concentration of all stable defects, due to their interaction with vacancies and interstitials. Their role in the mechanisms of formation and decomposition of the following stable defects: V_2, VO, V_2O, C_i, C_iO_i, C_iC_s and VP, is studied. The model predictions cover a generation primary rate of defects between 10^2 pairs/cm3/s and 10^{11} pairs/cm3/s, and could be a useful clue in obtaining harder materials for detectors for space missions, at the new generation of accelerators, as, e.g. LHC, Super-LHC and Eloisatron, or for industrial applications.

hep-ph↗
arXiv2003

Role of Oxygen and Carbon Impurities in the Radiation Resistance of Silicon Detectors

The influence of oxygen and carbon impurities on the concentrations of defects in silicon for detector uses, in complex fields of radiation (proton cosmic field at low orbits around the Earth, at Large Hadron Collider and at the next generation of accelerators as Super-LHC) is investigated in the frame of the quantitative model developed previously by the authors. The generation rate of primary defects is calculated starting from the projectile - silicon interaction and from recoil energy redistribution in the lattice. The mechanisms of formation of complex defects are explicitly analysed. Vacancy-interstitial annihilation, interstitial and vacancy migration to sinks, divacancy, vacancy and interstitial impurity complex formation and decomposition are considered. Oxygen and carbon impurities present in silicon could monitor the concentration of all stable defects, due to their interaction with vacancies and interstitials. Their role in the mechanisms of formation and decomposition of the following stable defects: VP, VO, V_2, V_2O, C_i, C_iO_i and C_iC_s is studied. The model predictions could be a useful clue in obtaining harder materials for detectors at the new generation of accelerators, for space missions or for industrial applications.

physics.ins-det↗
arXiv2002

The influence of initial impurities and irradiation conditions on defect production and annealing in silicon for particle detectors

Silicon detectors in particle physics experiments at the new accelerators or in space missions for physics goals will be exposed to extreme radiation conditions. The principal obstacles to long-term operation in these environments are the changes in detector parameters, consequence of the modifications in material properties after irradiation. The phenomenological model developed in the present paper is able to explain quantitatively, without free parameters, the production of primary defects in silicon after particle irradiation and their evolution toward equilibrium, for a large range of generation rates of primary defects. Vacancy-interstitial annihilation, interstitial migration to sinks, divacancy and vacancy-impurity complex (VP, VO, V2O, CiOi and CiCs) formation are taken into account. The effects of different initial impurity concentrations of phosphorus, oxygen and carbon, as well as of irradiation conditions are systematically studied. The correlation between the rate of defect production, the temperature and the time evolution of defect concentrations is also investigated.

physics.ins-det↗
arXiv2002

Radiation defects in silicon due to hadrons and leptons, their annealing and influence on detector performance

A phenomenological model was developed to explain quantitatively, without free parameters, the production of primary defects in silicon after particle irradiation, the kinetics of their evolution toward equilibrium and their influence on detector parameters. The type of the projectile particle and its energy is considered in the evaluation of the concentration of primary defects. Vacancy-interstitial annihilation, interstitial migration to sinks, vacancy - impurity complexes (VP, VO, V2O), and divacancy (V2) formation are taken into account in different irradiation conditions, for different concentrations of impurities in the semiconductor material, for 20 and 0 degrees C. The model can be extended to include other vacancy and interstitial complexes. The density of the reverse current in the detector after irradiation is estimated. Comparison with experimental measurements is performed. A special application considered in the paper is the modelled case of the behaviour of silicon detectors operating in the pion field estimated for the LHC accelerator, under continuum generation and annealing.

hep-ph↗
arXiv2001

Annealing of radiation induced defects in silicon in a simplified phenomenological model

The concentration of primary radiation induced defects has been previously estimated considering both the explicit mechanisms of the primary interaction between the incoming particle and the nuclei of the semiconductor lattice, and the recoil energy partition between ionisation and displacements, in the frame of the Lindhard theory. The primary displacement defects are vacancies and interstitials, that are essentially unstable in silicon. They interact via migration, recombination, annihilation or produce other defects. In the present work, the time evolution of the concentration of defects induced by pions in medium and high resistivity silicon for detectors is modelled, after irradiation. In some approximations, the differential equations representing the time evolution processes could be decoupled. The theoretical equations so obtained are solved analytically in some particular cases, with one free parameter, for a wide range of particle fluences and/or for a wide energy range of the incident particles, for different temperatures; the corresponding stationary solutions are also presented.

physics.ins-det↗
arXiv2000

Predictions about the behaviour of diamond, silicon, SiC and some AIIIBV semiconductor materials in hadron fields

The utilisation of crystalline semiconductor materials as detectors and devices operating in high radiation environments, at the future particle colliders, in space applications, in medicine and industry, makes necessary to obtain radiation harder materials. Diamond, SiC and different AIIIBV compounds (GaAs, GaP, InP, InAs, InSb) are possible competitors for silicon to different electronic devices for the up-mentioned applications. The main goal of this paper is to give theoretical predictions about the behaviour of these semiconductors in hadron fields (pions, protons). The effects of the interaction between the incident particle and the semiconductor are characterised in the present paper both from the point of view of the projectile, the relevant quantity being the energy loss by nuclear interactions, and of the target, using the concentration of primary radiation induced defects on unit particle fluence. Some predictions about the damage induced by hadrons in these materials in possible applications in particle physics and space experiments are done.

physics.ins-det↗