Dissertations / Theses on the topic 'Charged particle radiation'
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Testa, Mauro. "Charged particle therapy, ion range verification, prompt radiation." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00566188.
Full textKoziel, Michal. "Development of radiation hardened pixel sensors for charged particle detection." Strasbourg, 2011. http://www.theses.fr/2011STRA6237.
Full textCMOS Pixel Sensors are being developed since a few years to equip vertex detectors for future high-energy physics experiments with the crucial advantages of a low material budget and low production costs. The features simultaneously required are a short readout time, high granularity and high tolerance to radiation. This thesis mainly focuses on the radiation tolerance studies. To achieve the targeted readout time (tens of microseconds), the sensor pixel readout was organized in parallel columns restricting in addition the readout to pixels that had collected the signal charge. The pixels became then more complex, and consequently more sensitive to radiation. Different in-pixel architectures were studied and it was concluded that the tolerance to ionizing radiation was limited to 300 krad with the 0. 35-um fabrication process currently used, while the targeted value was several Mrad. Improving this situation calls for implementation of the sensors in processes with a smaller feature size which naturally improve the radiation tolerance while simultaneously accommodate all the in-pixel microcircuitry in small pixels. Another aspect addressed in this thesis was the tolerance to non ionizing radiation, with a targeted value of >1013 neq/cm2. Different CMOS technologies featuring an enhanced signal collection were therefore investigated. It was demonstrated that this tolerance could be improved to 3•1013 neq/cm2 by the means of a high-resistivity epitaxial layer. This achievement triggered a new age of the CMOS pixel sensors and showed that their development is on a good track to meet the requirements of the particularly demanding CBM experiment
Wei, Xiaomin. "Study and improvement of radiation hard monolithic active pixel sensors of charged particle tracking." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00953382.
Full textAdkins, Raymond. "A LIQUID CRYSTAL BASEDELECTRON SHOWER DETECTOR." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1522427297703445.
Full textKundu, Ashoke. "Monte Carlo simulation of gas-filled radiation detectors." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/987/.
Full textHarvey, Shaun. "Charged particle induced soft errors in 1 Mbit and 4 Mbit DRAMs as the basis for a portable radiation detector system." Thesis, University of Surrey, 1998. http://epubs.surrey.ac.uk/843953/.
Full textSöderberg, Jonas. "Dosimetry and radiation quality in fast-neutron radiation therapy : a study of radiation quality and dosimetric properties of fast-neutrons for external beam radiotherapy and problems associated with corrections of measured charged particle cross-sections /." Linköping : Division of Radiation Physics, Department of Medicine and Care, Faculty of Health Science, Linköping University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8589.
Full textSöderberg, Jonas. "Dosimetry and radiation quality in fast-neutron radiation therapy : A study of radiation quality and basic dosimetric properties of fast-neutrons for external beam radiotherapy and problems associated with corrections of measured charged particle cross-sections." Doctoral thesis, Linköpings universitet, Medicinsk radiofysik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8589.
Full textMuggiolu, Giovanna. "Deciphering the biological effects of ionizing radiations using charged particle microbeam : from molecular mechanisms to perspectives in emerging cancer therapies." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0599/document.
Full textFew years ago, the paradigm of radiation biology was that the biological effects of ionizing radiations occurred only if cell nuclei were hit, and that cell death/dysfunction was strictly due to unrepaired/misrepaired DNA. Now, next this “DNA-centric” view several results have shown the importance of “non-DNA centered” effects. Both non-targeted effects and DNA-targeted effects induced by ionizing radiations need to be clarified for the evaluation of the associated radiation resistance phenomena and cancer risks. A complete overview on radiation induced effects requires the study of several points: (i) analyzing the contribution of different signaling and repair pathways activated in response to radiation-induced injuries; (ii) elucidating non-targeted effects to explain cellular mechanisms induced in cellular compartments different from DNA; and (iii) improving the knowledge of sensitivity/resistance molecular mechanisms to adapt, improve and optimize the radiation treatment protocols combining ionizing radiations and nanoparticles. Charged particle microbeams provide unique features to answer these challenge questions by (i) studying in vitro both targeted and non-targeted radiation responses at the cellular scale, (ii) performing dose-controlled irradiations on a cellular populations and (iii) quantifying the chemical element distribution in single cells after exposure to ionizing radiations or nanoparticles. By using this tool, I had the opportunity to (i) use an original micro-irradiation setup based on charged particles microbeam (AIFIRA) with which the delivered particles are controlled in time, amount and space to validate in vitro methodological approaches for assessing the radiation sensitivity of different biological compartments (DNA and cytoplasm); (ii) assess the radiation sensitivity of a collection of cancerous cell lines derived from patients in the context of radiation therapy; (iii) study metal oxide nanoparticles effects in cells in order to understand the potential of nanoparticles in emerging cancer therapeutic approaches
Appelt, Eric. "Measurements of Charged-Particle Transverse Momentum Spectra in PbPb Collisions at Square Root of SNN = 2|76 TeV and in pPb Collisions at Square Root of SNN = 5|02 TeV with the CMS Detector." Thesis, Vanderbilt University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3584408.
Full textWarren, Daniel Rosevear. "Proton radiotherapy uncertainties arising from computed tomography." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:ab59f596-e277-490a-a7c1-1cb81b47b9a9.
Full textMossuz, Laurence. "Etude de la production et de la désintégration semi-électronique de particules charmées dans les diffusions inélastiques de neutrinos." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10087.
Full textJung, Yun Su. "Effects of charge distribution within a particle beam on the sub-Cerenkov radiation." Thesis, Monterey, California: U.S. Naval Postgraduate School, 1987. http://hdl.handle.net/10945/22767.
Full textStrube, Jan 1978. "Analysis of radiative decays of charged B mesons to baryonic final states." Thesis, University of Oregon, 2008. http://hdl.handle.net/1794/9022.
Full textThe abundance of B mesons at B factories opens the door to the search in rare decays for physics outside of the Standard Model. Flavor-changing neutral current transitions proceed only via higher order in the Standard Model, resulting in a b [arrow right] s³y branching fraction of about 3 x 10 -4 , but hypothesized particles could alter the rate significantly. Decays of B mesons that proceed via this electroweak penguin diagram are an interesting example of flavor-changing neutral currents, due to the large number of accessible final states with observables that are sensitive to new processes. This dissertation describes the analyses of such decays B - [arrow right] p ³, B - [arrow right] £ 0 p ³, B - [arrow right] p and B - [arrow right] p using about 350 million B meson pairs recorded by the BABAR detector in the years 2001 through 2006. In addition to the decay rate, the distribution of the invariant mass of the baryon pair is presented, using a method for statistical unfolding. The analysis is the first of these decays at the BABAR experiment and lays the groundwork for future analyses of the branching fractions and angular correlations of b [arrow right] s decays containing A hyperons and other baryons at BABAR or higher luminosity B factories.
Adviser: James E. Brau
Ozturk, Fahri. "Scalar Mesons In Radiative Phi-meson Decays Into Charged K-meson States." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609614/index.pdf.
Full textMcGarry, Stephen. "Irradiated silicon particle detectors." Thesis, Lancaster University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369468.
Full textOgul, Hasan. "Studies of muon efficiencies for measurement of W charge asymmetry in inclusive pp → W (muupsilon) production at s = 7 TeV." Thesis, The University of Iowa, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1545468.
Full textThe main motivation of the Compact Muon Solenoid (CMS) experiment is to explore and to discover physics underlying electro-weak asymmetry breaking. Beside this, CMS detector provides an opportunity to do various experiments for detecting new physics signatures beyond the Standard Model (SM). Investigation of these signatures requires the identification and precise energy and moment measurement of electrons, muons, photons, and jets. The objective of this thesis is the calculation of the efficiencies for the measurement of W charge asymmetry in inclusive pp → W (&mgr;υ) production. The charge asymmetry is defined to be the difference between W + and W− bosons, normalized to the sum. This asymmetry is sensitive to the u-quark and d-quark ratios in the proton and precise measurement of the W charge asymmetry can provides new insights to the proton structure functions. Therefore, to improve understanding of SM backgrounds in search for new physics, the moun trigger, isolation, reconstruction, identification efficiencies has been studied using partial data collected by the CMS detector during pp collisions at the LHC in 2011. The dataset corresponds to an integrated luminosity of 2.31 fb−1. The efficiencies are measured as functions of the decay muon pseudo rapidity and transverse momentum based on "tag and probe" method. The efficiency measurements are compared to their estimated value from the Monte Carlo simulations so as to provide scaling factors to correct to the residual mis-modeling of the CMS muon performance. The comparison with simulations based on MC simulations opens a gate for validation of the detector simulation and optimization of selection strategies.
Mahee, Durude. "Numerical Simulation and Graphical Illustration of Ionization by Charged Particles as a Tool toward Understanding Biological Effects of Ionizing Radiation." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535381068931831.
Full textBurmistrov, Leonid. "A detector for charged particle identification in the forward region of SuperB." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00673482.
Full textFomin, Alex. "Multiple Scattering Effects on the Dynamics and Radiation of Fast Charged Particles in Crystals. Transients in the Nuclear Burning Wave Reactor." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS272/document.
Full textThe coherent effects in the high energy particle interaction with crystals open up new opportunities for accelerating and detecting techniques. The effective electromagnetic fields that arise in this case can exceed a thousand times the fields that are now attainable at experimental installations. The first part of the thesis is devoted to the theoretical study of the multiple scattering effects on the dynamics and radiation of high energy charged particles in crystals. One of the goals of this study is to find optimal conditions to carry out the measurement of the anomalous magnetic moment of the charmed Lambda Baryon at the LHC. Due to the short lifetime of this particle the only way to provide such a measurement is to use a bent crystal, which can imitate the magnetic field of order of thousand Tesla. The optimization of the parameters for an experimental setup was carried out on the basis of computer simulation of the Lamda Baryon passage through a bent crystal using the binary collisions model, taking in to account incoherent scattering on thermal vibrations of atoms at lattice nodes, and scattering on an electronic subsystem of a crystal. The results of the research conducted in the thesis give an optimistic forecast for the possibility of carrying out such an experiment at the LHC and became the basis of the corresponding proposal. The multiple scattering effects of the thesis. This study is performed in the framework of classical electrodynamics approach for describing the relativistic particle radiation and the computer simulation of fast charged particles passing through a crystal using the above-mentioned model. It is shown, that the spectral-angular distribution and the polarization characteristics of radiation essentially differ from the results of the Bethe–Heitler theory. The conditions for the experimental observation of these effects are presented. The second part of the thesis is devoted to the study of transient processes in advanced fast reactor breeder working in a self-sustained nuclear burning wave (NBW) regime. It is a new concept of nuclear fission reactors with the so-called “intrinsic safety”, in which the development of uncontrolled chain nuclear reaction is impossible due to the physical principles of reactor operation. The promising concepts of NBW reactor in the case of its implementation allows to utilize the depleted Uranium and provides the treatment of long-lived radioactive waste. This study is based on numerical solving the non-stationary non-linear diffusion equation of neutron transport together with a set of the burn-up equations for fuel components and the equations of nuclear kinetics for precursor nuclei of delayed neutrons using effective multi-group approach. The model of cylindrical homogeneous reactor with metallic fuel of U–Pu, Th–U and mixed Th–U–Pufuel cycles is considered in the framework of the buckling concept. As a result of these studies the existence of the NBW mode in the case of mixed Th–U–Pu fuel and its essential advantages are demonstrated; the detailed analysis of a special kind of the negative reactivity feedback that is inherent to the NBW regime and underlies the “intrinsic safety” of such a reactor is performed; the scenarios of a smooth start-up, forced shutdown and subsequent restart of the NBW reactor are developed
Lalucaa, Valérian. "Etude des effets singuliers produits par les particules énergétiques chargées de l’environnement radiatif spatial sur les capteurs d’images CMOS." Thesis, Toulouse, ISAE, 2013. http://www.theses.fr/2013ESAE0042/document.
Full textThis thesis studies the single event effects of space environment in CMOS image sensors (CIS). This work focuses on the effects of heavy ions on 3T standard photodiode pixels, and 4T and 5T pinned photodiode pixels. The first part describes the space radioactive environment and the sensor architecture. The most harmful events (SEL and SETs) are identified thanks to the scientific literature. The experimentally tested sensors agree with the theoretical work. SETs are compared to STARDUST simulations with a good agreement for all ions and sensors. The work explains why the SETs on 3T pixels are insensitive to the various photodiode designs, and they are decreased when an epitaxial substrate is used. A method using anti-blooming was successfully used in 4T and 5T pixels to prevent the spread of the SETs. The mechanism of latchup in 4T pixel sensors is described. All the identified mechanisms are very useful to provide hardening methods for the CISs
Haas, Benjamin. "QCD sur réseau et physique du charme." Paris 11, 2009. http://www.theses.fr/2009PA112359.
Full textLn this thesis, we present the results of the study of the charm properties on the lattice. We used unquenched configuration with Wilson-like actions, i. E. Wilson--Clover and twisted-mass quark actions. We studied the decay of the $$D"\ast$$ meson and computed the coupling hadronic coupling $$g_{D"\ast D\pi}$$,the radiative coupling $$g_{D"\ast D\gamma}$$. We then studied the leptonic and semileptonic of the $$D_{(s)}$$-mesons. We constrained the CKM matrix entries $$\vert V_{cd} \vert$$ and $$\vert V_{cs} \vert$$
Moreau, Thomas. "Etude numérique et développement de spectromètres embarquables de particules chargées." Toulouse 3, 2003. http://www.theses.fr/2003TOU30032.
Full textBhat, Siddharth. "Design and characterization in depleted CMOS technology for particle physics pixel detector." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0267.
Full textThe ATLAS experiment will start operating at the High Luminosity LHC accelerator (HL-LHC) in 2026 to increase the probability of new discoveries. Depleted CMOS monolithic pixel detector technology has been one of the options considered for the outer layer of an upgraded ATLAS pixel detector and is a high potential technology for future pixel detectors. In this thesis, several prototypes have been developed using different depleted CMOS technologies, for instance, LFoundry (LF) 150 nm, TowerJazz (TJ) 180 nm and austriamicrosystems AG (AMS) 180 nm. In a high-energy environment like HL-LHC, Single Event Upsets (SEU), which become of concern for reliable circuit operation. Several test-chips in AMS, TowerJazz and LFoundry technologies with different SEU tolerant structures have been prototyped and tested. The SEU tolerant structures were designed with appropriate electronics simulations using Computer Aided Design (CAD) tools in order to study the sensitivity of injected charge to upset a memory state. An alternative powering scheme named Serial Powering scheme is foreseen for the future Inner Tracker (ITk) detector of the ATLAS experiment. To meet the requirements ofthe ATLAS experiment to the environment of a pixelated layer in a high radiation collider environment, new developments with depleted CMOS sensors have been made in Shunt-LDO regulator and sensor biasing which are designed in modified TowerJazz 180 nm CMOS imaging technology. In the TowerJazz modified process, two different voltage levels are used for the purpose of sensor depletion. The bias voltages are generated by using a negative charge pump circuit
Na, Dong-Yeop NA. "Electromagnetic Particle-in-Cell Algorithms on Unstructured Meshes for Kinetic Plasma Simulations." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543398838970791.
Full textKeane, Aidan J. "Liouville's equation and radiative acceleration in general relativity." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301358.
Full textLe, Foulher Fabrice. "Simulations Monte Carlo et mesures de l’émission de gamma prompts appliquées au contrôle en ligne en hadronthérapie." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10180/document.
Full textDuring the treatment of a tumor with light ions, the Bragg peak location must be accurately known. A significant fraction of the incident ions undergo nuclear collisions with the target nuclei leading to the prompt emission of particles which may carry information on the ion path. This work, which focuses on prompt gamma, shows that the depth profile of these emissions is highly correlated to the ions path and the measured counting rates allow to consider a realistic imaging system, operating in real time. For that purpose, we performed experiments at GANIL and at GSI with a collimated detector placed perpendicular to the beam axis and the time of flight technique was used in order to reduce the noise induced by neutrons and charged particles. Geant4 simulations were performed for the experimental design and data interpretation. A qualitative agreement between simulations and experiment is observed for the amount of energy deposited in the detector and the shape of the time of flight spectrum. However, discrepancies appear for the prompt gamma yield and the depth distribution of gamma detected. These discrepancies are discussed, mainly in terms of nuclear physics models that must be improved. After selecting the physical models which lead to the best agreement between simulations and measurements, studies on the location of prompt gamma emission and on the influence of diffusion in the target were performed to determine the impact on the correlation with the ion path
Scielzo, Nicholas David. "Measurement of the beta-neutrino correlation in laser trapped {sup 21}Na." Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/821455-YDxgQ2/native/.
Full textPublished through the Information Bridge: DOE Scientific and Technical Information. "LBNL--54350" Scielzo, Nicholas David. USDOE Director. Office of Science. Nuclear Physics (US) 06/01/2003. Report is also available in paper and microfiche from NTIS.
Beaucourt-Jacquet, Céline. "Étude expérimentale du guidage du faisceau d’électrons dans le cadre de l’allumage rapide de cibles de fusion." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14741/document.
Full textThe work presented in this thesis is realised in the framework of the fast ignition of inertial confinement fusion for energy production. In this scheme the compression and the ignition phases are decoupled. During the second phase, the electron beam must cross over 300 µm in the dense fuel to deposit its energy in the dense core and ignite the fusion reactions.The major problem of the scheme is related to the divergence of the electron beam while it crosses the dense matter. Among the different propositions to inhibit the electron divergence we consider here the schemes without cone that are based on the effect of magnetic collimation. In particular, A.P.L. Robinson and his co-authors [Phys. Rev. Lett. 100, 025002, 2008] suggested a simple way to control the electron beam divergence by using a sequence of two laser pulses. The first one creates a magnetic background favourable for the confinement of the second electron beam resulting from the second interaction. The validation of this scheme is the major goal of this thesis.We present the results of experimental sudies and numerical modeling of the electron beam guiding with help of two consequent laser pulses. The experiment was performed on the Vulcan facility at the Rutherford Appleton Laboratory at Didcot in UK, based on the proposal submitted by an international group of scientists in the framework of the European project for inertial fusion energy HiPER. This experiment allowed us to define a combination of laser and target parameters where the electron beam guiding takes place. The analysis of experimental data and numerical modelling is realised with the hydrodynamic code CHIC coupled to the charged particules transport module M1. The interpretation of the experimental results allowed us to explain the experimental data and the physical basis of guiding and to define the magnetic conditionflavourable to the electron beam guidance
Torrens, Caldentey Gabriel. "Estudio de eventos transitorios inducidos por radiación en memorias SRAM nanométricas." Doctoral thesis, Universitat de les Illes Balears, 2012. http://hdl.handle.net/10803/97291.
Full textRadiation effects in electronic circuits are known since the beginning of the space race in the 1960s, because out of the terrestrial atmosphere, radiation exposure level is higher than on the surface. However, electronic technology scaling has led to an increase in radiation susceptibility that can result in operation errors even at ground level. This thesis deals with a radiation effect, in SRAMs (Static Random Access Memory), named transient event, which is characterized by corrupting data stored in the memory without causing any permanent damage to it. Several techniques to design more robust memories against radiation effects are studied by simulation. In addition, an SRAM prototype, including some of these techniques, has been designed and manufactured. Finally, the effectiveness of these techniques has been experimentally validated through controlled irradiation of the circuit.
Els efectes de la radiació en circuits electrònics es coneixen des dels inicis de la carrera espacial als anys 60, ja que fora de l’atmosfera terrestre s’està exposat a nivells més alts de radiació que a la superfície. No obstant això, l’escalat de la tecnologia electrònica ha comportat un augment de la susceptibilitat a la radiació, que pot desembocar en errors de funcionament fins i tot a nivell de terra. Aquesta tesi estudia un efecte de la radiació, en memòries SRAM (Static Random Access Memory), anomenat event transitori, que es caracteritza per corrompre les dades emmagatzemades a la memòria sense danyar-la permanentment. S’estudien per simulació diverses tècniques per dissenyar memòries més robustes en front a events transitoris. A més, s’ha dissenyat i fabricat un prototipus d’SRAM que incorpora alguna d’aquestes tècniques. Finalment, s’ha validat experimentalment la seva eficàcia mitjançant la irradiació controlada del circuit.
Alhakeem, Eyad Ali. "Dosimetry at extreme non-charged particle equilibrium conditions using Monte Carlo and specialized dosimeters." Thesis, 2018. https://dspace.library.uvic.ca//handle/1828/10123.
Full textGraduate
2019-08-30
Schwab, John H. "Prolonged alterations of cardiomyocyte gene expression following low dose high charge and energy particle radiation--implications for future deep space travel." Thesis, 2015. https://hdl.handle.net/2144/16289.
Full textBouchami, Jihène. "Mesure des champs de radiation dans le détecteur ATLAS et sa caverne avec les détecteurs au silicium à pixels ATLAS-MPX." Thèse, 2013. http://hdl.handle.net/1866/9704.
Full textThe LHC proton-proton collisions create a hard radiation environment in the ATLAS detector. In order to quantify the effects of this environment on the detector performance and human safety, several Monte Carlo simulations have been performed. However, direct measurement is indispensable to monitor radiation levels in ATLAS and also to verify the simulation predictions. For this purpose, sixteen ATLAS-MPX devices have been installed at various positions in the ATLAS experimental and technical areas. They are composed of a pixelated silicon detector called MPX whose active surface is partially covered with converter layers for the detection of thermal, slow and fast neutrons. The ATLAS-MPX devices perform real-time measurement of radiation fields by recording the detected particle tracks as raster images. The analysis of the acquired images allows the identification of the detected particle types by the shapes of their tracks. For this aim, a pattern recognition software called MAFalda has been conceived. Since the tracks of strongly ionizing particles are influenced by charge sharing between adjacent pixels, a semi-empirical model describing this effect has been developed. Using this model, the energy of strongly ionizing particles can be estimated from the size of their tracks. The converter layers covering each ATLAS-MPX device form six different regions. The efficiency of each region to detect thermal, slow and fast neutrons has been determined by calibration measurements with known sources. The study of the ATLAS-MPX devices response to the radiation produced by proton-proton collisions at a center of mass energy of 7TeV has demonstrated that the number of recorded tracks is proportional to the LHC luminosity. This result allows the ATLAS-MPX devices to be employed as luminosity monitors. To perform an absolute luminosity measurement and calibration with these devices, the van der Meer method based on the LHC beam parameters has been proposed. Since the ATLAS-MPX devices response and the luminosity are correlated, the results of measuring radiation levels are expressed in terms of particle fluences per unit integrated luminosity. A significant deviation has been obtained when comparing these fluences with those predicted by GCALOR, which is one of the ATLAS detector simulations. In addition, radiation measurements performed at the end of proton-proton collisions have demonstrated that the decay of radionuclides produced during collisions can be observed with the ATLAS-MPX devices. The residual activation of ATLAS components can be measured with these devices by means of ambient dose equivalent calibration.
Gutierrez, Andrea. "Étude de la réponse du détecteur ATLAS-MPX aux neutrons rapides." Thèse, 2009. http://hdl.handle.net/1866/3785.
Full textATLAS-MPX detectors are Medipix2-USB detectors covered with lithium fluoride and polyethylene converters in order to increase the detection efficiency of slow neutrons and fast neutrons respectively. A network of fifteen ATLAS-MPX detectors has been put in operation in the ATLAS detector at CERN-LHC. Two reference detectors ATLAS-MPX were exposed to two fast neutrons sources 252 Cf and 241 AmBe as well as fast neutrons produced by the reaction 7 Li( p, xn) for the study of the detector response to those neutrons. Fast neutrons are primarily detected by recoil protons from elastic collisions between neutrons and hydrogen in the polyethylene. In addition, α -particles are produced by nuclear reactions between neutrons and silicon. A study of the efficiency of proton and alpha particle track recognition of Medipix2-USB was done as a function of the initial kinetic energy and incidence angle. The detection efficiency of fast neutrons was evaluated for two energy thresholds (8 keV and 230 keV) of ATLAS-MPX detector. The fast neutron detection efficiency of the detector region covered in polyethylene increases with neutron energy: (0.0346 ± 0.0004) %, (0.0862 ± 0.0018) % and (0.1044 ± 0.0026) % for fast neutrons of 2.13 MeV, 4.08 MeV and 27 MeV respectively. The method for the measurement of neutron energy allows an estimate of the neutron flux when the ATLAS MPX detector is in an unknown radiation field as it is the case in the ATLAS detector at LHC.