The LHCb RICH PMTs Readout Electronics and the Monitoring of the HPDs Quantum Efficiency

LHCb is one of the four main experiments under construction on the Large Hadron Collider at CERN. Its purpose is to study CP violation in B mesons and to look for new physics effects in rare decays of b-hadrons. Particle identification will be essential to enhance the signal/background ratio in the selection of physics channels. For this reason, the Ring Imaging Cherenkov technique has been implemented: two RICH detectors (RICH1 and RICH2) have been designed to cover the wide momentum range 1-150 GeV/c. The produced Cherenkov photons will be focused on two planes of Hybrid PhotoDetectors (HPDs), which are sensitive to external magnetic fields and then need to be shielded. Despite the shielding, however, there will be some fringe field inside the HPDs volume and so it is necessary to experimentally check what is the behaviour of each photodetector when the LHCb dipole magnet is on and the HPDs are illuminated by test patterns. In RICH2, two LED projectors based on the Digital Light Processing technology are exploited to generate the test patterns, which have to be precisely aligned on the two HPD planes. The matching procedure is carried out using six PMTs permanently placed inside the HPD matrices. The work described in this thesis concerns the design, realization and test of the PMTs readout system, both on the HW and SW level. In the last chapter, I will also try to evaluate the possibility to periodically monitor the HPDs Q.E. using the same beamer selected for the magnetic distortion tests. Chapter 1 is an introduction to CERN and the LHCb experiment. Paragraph 1.2 focuses on the two RICH sub-systems, while in 1.3 the HPD working principle is described. In paragraph 2.1 I describe the PMTs installed in the RICH2, while the rest of the chapter is dedicated to the DLP projectors to be used during the magnetic distortion tests. In particular, 2.2 illustrates the DLP technology, while 2.4 and 2.5 are about the beamers tests. Chapter 3 is dedicated to the PMTs readout electronics design, realization and test. After a theoretical study carried out in paragraph 3.1, in 3.2 I describe the realized shaper amplifier prototype. In 3.3 the choice of the digitiser to be installed in cascade to the shaper is discussed and the DAQ software program is described, while 3.4 summarizes the results obtained testing the prototype with the real signals. In 3.5 the final six-channel shaper amplifier + ADC is presented and tested, while 3.6 describes the installation of this module in the pit environment. Finally, in chapter 4 I estimate the sensitivity of the HPD Q.E. monitoring based on the magnetic distortion test apparatus

On the Boomerang Uniformity of some Permutation Polynomials

The boomerang attack, introduced by Wagner in 1999, is a cryptanalysis technique against block ciphers based on differential cryptanalysis. In particular it takes into consideration two differentials, one for the upper part of the cipher and one for the lower part, and it exploits the dependency of these two differentials. At Eurocrypt’18, Cid et al. introduced a new tool, called the Boomerang Connectivity Table (BCT), that permits to simplify this analysis. Next, Boura and Canteaut introduced an important parameter for cryptographic S-boxes called boomerang uniformity, that is the maximum value in the BCT. Very recently, the boomerang uniformity of some classes of permutations (in particular quadratic functions) have been studied by Li, Qu, Sun and Li, and by Mesnager, Tang and Xiong. In this paper we further study the boomerang uniformity of some non-quadratic differentially 4-uniform functions. In particular, we consider the case of the Bracken-Leander cubic function and three classes of 4-uniform functions constructed by Li, Wang and Yu, obtained from modifying the inverse functions.publishedVersio

Anomalous Weak Values and the Violation of a Multiple-measurement Leggett-Garg Inequality

Quantum mechanics presents peculiar properties that, on the one hand, have been the subject of several theoretical and experimental studies about its very foundations and, on the other hand, provide tools for developing new technologies, the so-called quantum technologies. The nonclassicality pointed out by Leggett-Garg inequalities has represented, with Bell inequalities, one of the most investigated subject. In this letter we study the connection of Leggett-Garg inequalities with a new emerging field of quantum measurement, the weak values. In particular, we perform an experimental study of the four-time correlators Legget-Garg test, by exploiting single and sequential weak measurements performed on heralded single photons. We show violation of a four-parameters Leggett-Garg inequality in different experimental conditions, demonstrating an interesting connection between Leggett-Garg inequality violation and anomalous weak values

A comparison of eight metamodeling techniques for the simulation of N2O fluxes and N leaching from corn crops

International audienceThe environmental costs of intensive farming activities are often under-estimated or not traded by the market, even though they play an important role in addressing future society's needs. The estimation of nitrogen (N) dynamics is thus an important issue which demands detailed simulation based methods and their integrated use to correctly represent complex and non-linear interactions into cropping systems. To calculate the N2O flux and N leaching from European arable lands, a modeling framework has been developed by linking the CAPRI agro-economic dataset with the DNDC-EUROPE bio-geo-chemical model. But, despite the great power of modern calculators, their use at continental scale is often too computationally costly. By comparing several statistical methods this paper aims to design a metamodel able to approximate the expensive code of the detailed modeling approach, devising the best compromise between estimation performance and simulation speed. We describe the use of two parametric (linear) models and six non-parametric approaches: two methods based on splines (ACOSSO and SDR), one method based on kriging (DACE), a neural networks method (multilayer perceptron, MLP), SVM and a bagging method (random forest, RF). This analysis shows that, as long as few data are available to train the model, splines approaches lead to best results, while when the size of training dataset increases, SVM and RF provide faster and more accurate solutions

On relations between CCZ- and EA-equivalences

In the present paper we introduce some sufficient conditions and a procedure for checking whether, for a given function, CCZ-equivalence is more general than EA-equivalence together with taking inverses of permutations. It is known from Budaghyan et al. (IEEE Trans. Inf. Theory 52.3, 1141–1152 2006; Finite Fields Appl. 15(2), 150–159 2009) that for quadratic APN functions (both monomial and polynomial cases) CCZ-equivalence is more general. We prove hereby that for non-quadratic APN functions CCZ-equivalence can be more general (by studying the only known APN function which is CCZ-inequivalent to both power functions and quadratics). On the contrary, we prove that for power non-Gold APN functions, CCZ equivalence coincides with EA-equivalence and inverse transformation for n ≤ 8. We conjecture that this is true for any n.acceptedVersio

Radioluminescence of synthetic and natural quartz

The effect of X-ray irradiation and thermal treatments on the radio-luminescence emission spectrum of both a natural pegmatitic quartz and a synthetic one was investigated. All the emission spectra could be deconvolved into the same set of five Gaussian components. Among the identified RL bands, a blue emission at 2.53 eV (480 nm) is enhanced under X-ray irradiation. A strong correlation with the sensitization of the so called "110 degrees C" TSL peak (in our measurements seen at lower temperature due to the lower heating rate) was proved, suggesting that the recombination centers associated with the 2.53 eV band are produced under X-ray irradiation and are involved in both RL and TSL luminescence mechanisms. When each irradiation was followed by heating up to 500 degrees C a strong sensitization of the RL band emitting at 3.44 eV and of the 110 degrees C TSL peak were observed. A perfect correlation between the RL and TSL emissions suggests that the recombination centers involved in the RL and TSL emissions are the sam

A comparison of three learning methods to predict N2O fluxes and N leaching

International audienceThe environmental costs of intensive farming activities are often under-estimated or not included into rural development plans, even though they play an important role in addressing future society's needs. This paper focuses on the use of statistical learning methods to predict N2O emissions and N leaching under several conservative scenarios, in order to provide an alternative approach to deterministic models on a macro-scale. To that aim, three learning methods, namely neural networks (multilayer perceptrons), SVM and random forests, are compared and provide accurate solutions

A Comparison of Three Learning Methods to Predict N2O Fluxes and N Leaching

The environmental costs of intensive farming activities are often under-estimated or not included into the rural development plans, even though they play an important role in addressing future society¿s needs. This paper focus on the use of statistical learning methods to predict the N2O emissions and N leaching under several conservative scenarios, in order to provide an alternative approach to deterministic models at macro-scale. To that aim, three learning methods, namely neural networks (multilayer perceptrons), SVM and random forests, are compared and provide accurate solutions.JRC.DDG.H.2-Climate chang

RILDOS: A Beaconing Standard for Small Satellite Identification and Situational Awareness

The increasing launch pace of small satellites and CubeSats presents a growing challenge to identify and locate newly launched satellites. This impacts mission success primarily through the inability to consistently perform rapid and accurate determination of satellite identity and orbital location after deployment. This paper proposes an approach to resolve this issue through a simple radio and message broadcast standard providing definitive identification, location, and operational state data on a low power, very low data rate subcarrier. Called RILDOS (Radio with Identity and Location Data for Operations and SSA [Space Situational Awareness]), this would be an open standard available for use in new systems. RILDOS is a repeating, unencrypted message broadcast with a unique identifier, timestamp, spacecraft derived position / velocity / acceleration, and predefined emergency flags. The spread spectrum signal is transmitted at a low power and very low data rate and can be radiated continuously or only while in contact. Centering the signal underneath the primary radio frequency for the satellite avoids the need for additional frequency deconfliction or a secondary radio. Cycling every ten seconds, a short collection gathers enough data for an orbital determination as well as top level status about the health of the satellite