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Together with the ongoing works on preparations of High-Luminosity LHC, there is a need to enhance the performance of various experiments on the collider as well. This is also the case of the experiment ATLAS and its subdetectors such as Inner Detector which will be completely replaced by new all-silicon Inner Tracker (ITk). This thesis deals with computer simulations of silicon strip detec- tors for ATLAS Upgrade ITk. For this purpose, we are using framework AllPix2 . It enables to simulate everything from the interaction of the particle with silicon, charge propagation in electric and magnetic fields, charge collection, up to signal digitization. We focused mostly on three aspects in the simulations. The first is a precise characterization of used detectors, the second is a simulation of a test beam measurements and the third one is a simulation of test measurements with a radioactive beta source. We also discussed the possibility of simulation of test measurements with a laser. These simulations are important not only because they help us to better understand processes happening inside the detector, but they are also used as a validation of testing measurements. As a result of this, we are able to point out the effects of the experimental setup (or detector itself) which have an impact on measured...

The ATLAS experiment is currently undergoing a modernization, called the ATLAS Upgrade. Nowadays, simulations are an important part of planning new detectors and their modernization. They help us optimize their design before production and later verify the results obtained from the experiment. This work is focused on the simulation of edge eects on a silicon strip detector using a framework Allpix2 . In the beginning, we had no information, that any edge eects or even any irregular eects, is possible to simulate in Allpix2 . We rst veried that in the case of a simple irregular electric eld. We had at our disposal measurements performed at the Institute of Particle and Nuclear Physics, with which we compared the simulation. The signal obtained from the edge strip has dierent behaviour and is wider than the other strips. Therefore, we extended the electric eld of the edge strip in the simulation and modied it in various ways. 1

Beta Source Tests of Semiconductor Detectors ITk for ATLAS Upgrade Abstract: The ATLAS experiment is due to undergo a major upgrade for the High Luminosity phase of the LHC operation. In particular, the current tracking system (ID) will be replaced by full-silicon ITk. IPNP laboratories are involved in R&D of SCT detector modules for ITk. Low-temperature β-source tests of the R0 FR 5 module prototype were the main focus of this thesis. After testing the cooling cycle, 11 threshold scans were performed on two ABC130 chips, yielding the median collected charge ranging between 2.9 ± 0.2 fC and 3.1 ± 0.2 fC for chip #6 at SNR from 16.0 ± 1.0 at 24 ◦ C to 22.7 ± 1.5 at −15 ◦ C. No trend with temperature was observed outside the error bars. The results are in accordance with previous similar measurements. Question of fitting the median collected charge in various units was adressed and equivalence of the fits was determined. The ability of IPNP laboratories to perform low-temperature β-source tests was proven.

Neste trabalho descreve-se o estudo do estabelecimento de uma técnica para o crescimento e preparo de cristais de HgI2, com o intuito de utilizá-los como detectores semicondutores de radiação que operam a temperatura ambiente. Três métodos de crescimento de cristais foram estudados no desenvolvimento deste trabalho: (1) Transporte Físico de Vapor (Physical Vapor Transport PVT), (2) Solução Saturada de HgI2 empregando dois solventes distintos; Dimetil Sulfóxido (DMSO) (a) e acetona (b) e (3) método de Bridgman. A fim de avaliar os cristais de HgI2 desenvolvidos pelos três métodos, medidas sistemáticas foram realizadas para determinar a estrutura, o plano de orientação, a estequiometria, a morfologia da superfície e as impurezas do cristal. A influência destas propriedades físico-químicas sobre os cristais desenvolvidos foi avaliada em termos de desempenho como detector de radiação. Os difratogramas indicaram que os cristais estão orientados preferencialmente planos (001) e (101) com estrutura tetragonal para todos os cristais desenvolvidos. No entanto, a morfologia com menor nível de deformação foi observada para o cristal obtido pela técnica de PVT. Uma uniformidade na camada de superfície do cristal de PVT foi observada, enquanto na superfície do cristal de DMSO podem ser nitidamente encontradas incrustações de elementos distintos ao cristal. A melhor resposta de radiação foi encontrada para os cristais crescidos pela PVT. Significativa melhora no desempenho do detector de radiação de HgI2 foi encontrada, purificando o cristal por meio de dois crescimentos sucessivos, pela técnica de PVT. / In this work, the establishment of a technique for HgI growth and preparation of crystals, for use as room temperature radiation semiconductor detectors is described. Three methods of crystal growth were studied while developing this work: (1) Physical Vapor Transport (PVT); (2) Saturated Solution of HgI2, using two different solvents; (a) dimethyl sulfoxide (DMSO) and (b) acetone, and (3) the Bridgman method. In order to evaluate the obtained crystals by the three methods, systematic measurements were carried out for determining the stoichiometry, structure, orientation, surface morphology and impurity of the crystal. The influence of these physical chemical properties on the crystals development was studied, evaluating their performance as radiation detectors. The X-ray diffractograms indicated that the crystals were, preferentially, oriented in the (001) e (101) directions with tetragonal structure for all crystals. Nevertheless, morphology with a smaller deformation level was observed for the crystal obtained by the PVT technique, comparing to other methods. Uniformity on the surface layer of the PVT crystal was detected, while clear incrustations of elements distinct from the crystal could be viewed on the DMSO crystal surface. The best results as to radiation response were found for the crystal grown by physical vapor transport. Significant improvement in the HgIz2 radiation detector performance was achieved for purer crystals, growing the crystal twice by PVT technique.

Neste trabalho descreve-se o estudo do estabelecimento de uma técnica para o crescimento e preparo de cristais de HgI2, com o intuito de utilizá-los como detectores semicondutores de radiação que operam a temperatura ambiente. Três métodos de crescimento de cristais foram estudados no desenvolvimento deste trabalho: (1) Transporte Físico de Vapor (Physical Vapor Transport PVT), (2) Solução Saturada de HgI2 empregando dois solventes distintos; Dimetil Sulfóxido (DMSO) (a) e acetona (b) e (3) método de Bridgman. A fim de avaliar os cristais de HgI2 desenvolvidos pelos três métodos, medidas sistemáticas foram realizadas para determinar a estrutura, o plano de orientação, a estequiometria, a morfologia da superfície e as impurezas do cristal. A influência destas propriedades físico-químicas sobre os cristais desenvolvidos foi avaliada em termos de desempenho como detector de radiação. Os difratogramas indicaram que os cristais estão orientados preferencialmente planos (001) e (101) com estrutura tetragonal para todos os cristais desenvolvidos. No entanto, a morfologia com menor nível de deformação foi observada para o cristal obtido pela técnica de PVT. Uma uniformidade na camada de superfície do cristal de PVT foi observada, enquanto na superfície do cristal de DMSO podem ser nitidamente encontradas incrustações de elementos distintos ao cristal. A melhor resposta de radiação foi encontrada para os cristais crescidos pela PVT. Significativa melhora no desempenho do detector de radiação de HgI2 foi encontrada, purificando o cristal por meio de dois crescimentos sucessivos, pela técnica de PVT. / In this work, the establishment of a technique for HgI growth and preparation of crystals, for use as room temperature radiation semiconductor detectors is described. Three methods of crystal growth were studied while developing this work: (1) Physical Vapor Transport (PVT); (2) Saturated Solution of HgI2, using two different solvents; (a) dimethyl sulfoxide (DMSO) and (b) acetone, and (3) the Bridgman method. In order to evaluate the obtained crystals by the three methods, systematic measurements were carried out for determining the stoichiometry, structure, orientation, surface morphology and impurity of the crystal. The influence of these physical chemical properties on the crystals development was studied, evaluating their performance as radiation detectors. The X-ray diffractograms indicated that the crystals were, preferentially, oriented in the (001) e (101) directions with tetragonal structure for all crystals. Nevertheless, morphology with a smaller deformation level was observed for the crystal obtained by the PVT technique, comparing to other methods. Uniformity on the surface layer of the PVT crystal was detected, while clear incrustations of elements distinct from the crystal could be viewed on the DMSO crystal surface. The best results as to radiation response were found for the crystal grown by physical vapor transport. Significant improvement in the HgIz2 radiation detector performance was achieved for purer crystals, growing the crystal twice by PVT technique.

Master of Science / Department of Mechanical and Nuclear Engineering / J. Kenneth Shultis / Perforated neutron detectors suffer the unfortunate effect that their efficiency is a strong function of the direction of neutron incidence. It is found, by Monte Carlo simulation of many perforation shapes, that sinusoidal-type perforations greatly reduce the variation of detector efficiency. Detectors with rod-type perforations are modeled using a hybrid transport method linking the MCNP transport code and a specialized ion-transport code to calculate the probability that a neutron is detected. Channel, chevron, and sinusoidal perforations are modeled using other customized transport codes. Detector efficiency calculations are performed for neutrons incident at various polar and azimuthal angles. It is discovered that the efficiency losses of the detectors result from the decreasing solid angle subtended by the detector from the source and streaming through the detector at specific azimuthal angles. Detectors achieving an efficiency in excess of 10% and having a relatively flat ± 1% angular dependence in all azimuthal angles and polar angles between 0 and 60 degrees are predicted. Efficiencies up to 25% are achievable at the loss of directional independence. In addition to minimizing the directional dependence of the perforated detectors, the feasibility of developing a neutron detector for deployment in cargo containers to locate nuclear weapon pits is investigated using the MCNP transport code. The detector considered is a 7-mm diameter, 6LiF, rod-perforated detector surrounded in a cylinder of polyethylene. The optimum thicknesses of surrounding polyethylene, to maximize the response of the detector, is determined to be 10 cm of radial, 5 cm of front, and 5 cm of back polyethylene for end-on neutron incidence. Such a detector is predicted to produce a count rate between 12 and 15 cpm from a nuclear-weapon pit composed of 90% 239Pu and 10% 240Pu at a distance of 3 m. Side incidence is also considered, and the optimum moderator dimensions are 8 cm of radial, 10 cm of front, and 10 cm of back polyethylene that produce approximately the same count rate.

A basic requirement for all therapeutic applications of ionizing radiation is the high accuracy of delivery of the prescribed dose to the target volume of tissue healing. Each radiotherapy department must have in the quality assurance program developed methodology for testing the operational stability, which are reviewed and approved by The State Office for Nuclear Safety (SÚJB). A part of testing the operational stability of linear accelerators is also a regular assessment and measurement of parameters of radiation field, which is done by measuring the dose profiles. The thesis presents the results of measurement and evaluation of photon beam dose profiles of a linear accelerator, measured using the line-semiconductor detector (LDA-99SC company IBA) in the automatic water phantom under the reference conditions and their comparison with results obtained from measurement with the ionization chamber under the same terms of reference. The advantage of using a linear detector is a semiconductor that consists of 99 individual detectors in one line at a distance of 5 mm from each other and is able to measure the radiation dose profile field in a much shorter time than using an ionization chamber, where only one detector output can measure dose point after point. Usage of any other independent system for...

The high-radiation environment in space can lead to anomalies in normal satellite operation. A major cause of concern to spacecraft-designers is the single event upset (SEU). SEUs can result in deviations from expected component behavior and are capable of causing irreversible damage to hardware. In particular, Field Programmable Gate Arrays (FPGAs) are known to be highly susceptible to SEUs. Radiation-hardened versions of such devices are associated with an increase in power consumption and cost in addition to being technologically inferior when compared to contemporary commercial-off-the-shelf (COTS) parts. This thesis consequently aims at exploring the option of using COTS FPGAs in satellite payloads. A framework is developed, allowing the SEU susceptibility of such a device to be studied. SEU testing is carried out in a software-simulated fault environment using a set of Java classes called JBits. A radiation detector module, to measure the radiation backdrop of the device, is also envisioned as part of the final design implementation.

This thesis is focused on beta source tests of prototypes of ITk Strip modules at IPNP in Prague in the framework of the ATLAS Upgrade project. New expe- rimental apparatus will allow comparison of beta source test results with other testing methods including laser or test beam. I participated in the assembly of the whole apparatus, script development for a number of automated measurements using specialized ITSDAQ software and ROOT. Finally, summary of obtained properties of tested end-cap R0 DAQload with mini sensor is provided based on beta source tests and characterization of the readout chip. The resulting collec- ted charge value corresponds to 3.1 fC and together with often referred quantity signal-to-noise ratio, which equals 35, it is one of the most important results of the thesis. The experimental arrangement including overall analysis of results will be usable for the future production phase of the project. 1