Dissertation presented in ful lment of the requirements for the degree of: Master of Science in Physics 2016 / The Phase-II upgrade of the Large Hadron Collider at CERN in the early 2020s will enable an order of magnitude increase in the data produced, unlocking the potential for new physics discoveries. In the ATLAS detector, the upgraded Hadronic Tile Calorimeter (TileCal) Phase-II front end read out system is currently being prototyped to handle a total data throughput of 5.1 TB/s, from the current 20.4 GB/s. The FPGA based Super Read Out Driver (sROD) prototype must perform an energy reconstruction algorithm on 2.88 GB/s raw data, or 275 million events per second. Due to the very high level of pro ciency required and time consuming nature of FPGA rmware development, it may be more e ective to implement certain complex energy reconstruction and monitoring algorithms on a general purpose, CPU based sROD co-processor. Hence, the feasibility of a general purpose ARM System on Chip based co-processing unit (PU) for the sROD is determined in this work. A PCI-Express test platform was designed and constructed to link two ARM Cortex-A9 SoCs via their PCI-Express Gen-2 x1 interfaces. Test results indicate that the latency of the PCI-Express interface is su ciently low and the data throughput is superior to that of alternative interfaces such as Ethernet, for use as an interconnect for the SoCs to the sROD. CPU performance benchmarks were performed on ve ARM development platforms to determine the CPU integer, oating point and memory system performance as well as energy e ciency. To complement the benchmarks, Fast Fourier Transform and Optimal Filtering (OF) applications were also tested. Based on the test results, in order for the PU to process 275 million events per second with OF, within the 6 s timing budget of the ATLAS triggering system, a cluster of three Tegra-K1, Cortex-A15 SoCs connected to the sROD via a Gen-2 x8 PCI-Express interface would be suitable. A high level design for the PU is proposed which surpasses the requirements for the sROD co-processor and can also be used in a general purpose, high data throughput system, with 80 Gb/s Ethernet and 15 GB/s PCI-Express throughput, using four X-Gene SoCs.

Nuclear reactors have played an essential role in developing our current understanding of neutrinos. The precision measurement of these high-flux, pure-flavor and controllable artificial neutrino sources shed lights on a wide range of fundamental questions in physics. Specifically, the Reactor Antineutrino Anomaly hints that there may exist a novel eV-scale sterile neutrino, which requires new physics beyond the Standard Model. Performing reactor neutrino spectrum measurements at very-short baseline will improve our imperfect understanding of antineutrino emission from fissile material. CHANDLER is a new-generation neutrino experiment aiming for reactor antineutrino spectrum measurements, to test the eV-scale sterile neutrino oscillation hypothesis unambiguously. The second prototype detector, MiniCHANDLER, was deployed 25 meters from a $2.9~GW_{th}$ commercial nuclear reactor in North Anna, Virginia. To fight against the overwhelming background arising from its surface-level deployment, CHANDLER detectors adopt a novel design using lithium-6 ($^6$Li) loaded zinc sulfide (ZnS) scintillator to tag neutron capture events, which significantly improves the IBD detection efficiency. The use of the Raghavan optical lattice brings enormous enhancement of light collection towards high energy resolution, which unlocks reconstruction of event topology to further suppress backgrounds. The ability of measuring reactor antineutrino spectra enables the potential application of CHANDLER technology in nuclear nonproliferation. This thesis features the prototype detectors instrumentation, data analysis development and Monte Carlo study for the CHANDLER experiment during 2016 to 2020. The detector calibration and energy reconstruction with vertical muon forms a core piece of this thesis. We report our observation of IBD spectrum with 5.5$sigma$ significance with a four month deployment of the minimal shielded MiniCHANDLER prototype at North Anna. The application of separation cuts and topological selections in the analysis are instrumental for a segmented plastic scintillator detector. We also present our results from the proton scintillation quenching measurement at Triangle Universities Nuclear Laboratory, with the deployment of the first prototype detector, MicroCHANDLER, at a neutron beam. / Doctor of Philosophy / The sterile neutrino is a hypothetical particle yet to be observed, whose existence is suggested by a number of physics experiments with strong theoretical motivation. Due to the low chance of a neutrino interacting with matter, most neutrino detectors use a special process called inverse beta decay (IBD) to detect them. The CHANDLER experiment set out to measure antineutrinos produced by a reactor in the vicinity of its core. We found a significant signal of antineutrinos from our four-month deployment. This thesis details the technology and analysis that enables neutrino detection and improves detection efficiency. We also shows how we squeeze out the maximum information available to us from raw data, through the process called reconstruction. Other research topics related to the CHANDLER detector RandD are also included in this thesis.

Diese Arbeit beschreibt die Entwicklung einer Methode zur Energierekonstruktion von Myonen in Unterwasserteleskopen unter Verwendung der Amplituden und Trefferwahrscheinlichkeiten der Photomultiplier. Die Methode wird auf die Daten des Myon- und Neutrinoteleskopes NT-96 angewandt. / This thesis describes the development of a method for energy reconstruction of muons which are detected in underwater elescopes using the amplitudes and hit patterns of the photo multipliers. The method is applied to the data of the Baikal NT-96 muon and neutrino telescope.

One of the goals of the LHC is to test the existence of the Higgs Boson. This thesis presents a study of the potential to discover the Standard Model Higgs boson in the vector boson fusion (VBF) channel for the Higgs mass range 120-200 GeV/c2. The decay of Higgs bosons into WW* final state with both W-bosons decaying leptonically is considered. The main backgrounds are tt_+j and W+W-jj. This study, based on a full simulation of the CMS detector at the LHC, shows that a 5(Sigma) discovery can be done with an integrated luminosity of 12-72 fb-1 for 130-200 GeV/c2 Higgs bosons. Due to the uncertainties in the backgrounds, it is important to measure the backgrounds from data. This study shows that the major background can be measured directly to 7% with 30 fb-1. After discovering the Higgs boson mass using transverse mass template distributions is investigated in the VBF channel. The performance of the combined CMS electromagnetic and hadronic calorimeters (EB+HB) was measured at the H2 test beam at the CERN SPS during 2006 with various partivles in a large momentum range, 1-350 GeV/c. Another major contribution of this thesis is developing the method to optimize the energy reconstruction for the combined EB+HB system with which the corrected responses become 100% with 6% fluctuation and the stochastic resolution is improved from 111% to 94%.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-25T14:05:10Z No. of bitstreams: 1 joaopaulobittencourtdasilveiraduarte.pdf: 8307204 bytes, checksum: a026db8104dd8767f6e5b0fc71d452e9 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-25T15:27:51Z (GMT) No. of bitstreams: 1 joaopaulobittencourtdasilveiraduarte.pdf: 8307204 bytes, checksum: a026db8104dd8767f6e5b0fc71d452e9 (MD5) / Made available in DSpace on 2017-04-25T15:27:51Z (GMT). No. of bitstreams: 1 joaopaulobittencourtdasilveiraduarte.pdf: 8307204 bytes, checksum: a026db8104dd8767f6e5b0fc71d452e9 (MD5) Previous issue date: 2015-08-27 / Este trabalho apresenta um estudo sobre técnicas de deconvolução de sinais para a reconstrução online de energia no primeiro nível de trigger do calorímetro hadrônico (TileCal) do ATLAS. O ambiente de alta luminosidade, previsto para ocorrer nos próximos anos no colisionador de partículas LHC, aumenta a probabilidade de ocorrência de colisões adjacentes, promovendo o efeito de empilhamento de sinais. O algoritmo atualmente utilizado para a reconstrução de energia não é robusto a este efeito. Neste trabalho, o TileCal é interpretado como um canal de comunicação, cuja a resposta ao impulso deve ser compensada a fim de remover o efeito de empilhamento e recuperar a informação de energia depositada em cada colisão. Os métodos desenvolvidos requisitam uma implementação online. As FPGAs, por serem dispositivos reconfiguráveis e de alta velocidade, foram escolhidas para implementação destes algoritmos. Assim, neste trabalho avaliou-se dois tipos de técnicas de deconvolução, uma direta baseada em filtros FIR e outra baseada em métodos iterativos. O segundo tipo de técnica, permite uma melhora de desempenho na reconstrução pela possibilidade de se utilizar um conhecimento especialista de que a energia reconstruída deve ser sempre positiva. Os resultados da avaliação mostram que os métodos propostos apresentam maior desempenho, em alta luminosidade, do que o método atualmente implementado. Como esperado, os métodos iterativos reconstroem a energia com menor erro quando comparados às técnicas baseadas em filtros FIR. Porém, com relação a implementação, as técnicas iterativas são de maior complexidade e utilizam mais recursos de hardware. / This work presents a study of deconvolution techniques to be used in the online energy reconstruction for the ATLAS hadronic calorimeter (TileCal) first level trigger system. The high-luminosity environment, foreseen for the next years of operation of the LHC particle collider, increases the probability of observe adjacent collisions, promoting the signal superposition effect. The current algorithm for energy reconstruction is not robust against this pile-up effect. In this work, the TileCal is considered as a communication channel whose impulse response must be compensated in order to remove the pile-up effect and to recover the deposited energy information at each collision. The developed methods require an online implementation. Since FPGAs are suitable for high-speed applications, they are chosen to be used in the ATLAS trigger system. Therefore, in this work two different online deconvolution techniques were tested, a direct FIR filter implementation and techniques based on iterative processes. The later outperforms the former due to the possibility of imposing a constraint for reconstructing only positive energies, which is know to reflect the reality. The results have shown that the proposed methods present better reconstruction performance than the current employed method when the environment presents superposition effect (high luminosity). As expected, the iterative methods present smaller errors than the direct FIR methods. However, regarding the FPGA implementation, the iterative techniques have a higher computational cost and uses more hardware resources.