Artur Lobanov

The High Luminosity phase of the Large Hadron Collider will deliver 10 times more integrated luminosity than the existing collider, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry. As part of its upgrade program, the Compact Muon Solenoid collaboration is designing a high-granularity calorimeter (HGCAL) to replace the existing endcap calorimeters. It will feature unprecedented transverse and longitudinal readout and triggering segmentation for both electromagnetic and hadronic sections. The electromagnetic section and a large fraction of the hadronic section will be based on hexagonal silicon sensors of 0.5–1 cm2 cell size, with the remainder of the hadronic section being based on highly-segmented scintillators with silicon photomultiplier readout. The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection. First hexagonal silicon modules, using the existing Skiroc2 front-end ASIC developed for CALICE, have been tested in beams at Fermilab and CERN in 2016. We present results from these tests, in terms of system stability, calibration with minimum-ionizing particles and resolution (energy, position and timing) for electrons, and the comparisons of these quantities with GEANT4-based simulation.

We present measurements of the reduction of light output by plastic scintillators irradiated in the CMS detector during the 8 TeV run of the Large Hadron Collider and show that they indicate a strong dose rate effect. The damage for a given dose is larger for lower dose rate exposures. The results agree with previous measurements of dose rate effects, but are stronger due to the very low dose rates probed. We show that the scaling with dose rate is consistent with that expected from diffusion effects.

We study various machine learning based algorithms for performing accurate jet flavor classification on field-programmable gate arrays and demonstrate how latency and resource consumption scale with the input size and choice of algorithm. These architectures provide an initial design for models that could be used for tagging at the CERN LHC during its high-luminosity phase. The high-luminosity upgrade will lead to a five-fold increase in its instantaneous luminosity for proton-proton collisions and, in turn, higher data volume and complexity, such as the availability of jet constituents. Through quantization-aware training and efficient hardware implementations, we show that O(100) ns inference of complex architectures such as deep sets and interaction networks is feasible at a low computational resource cost.

The technological prototype of the CALICE highly granular silicon–tungsten electromagnetic calorimeter (SiW-ECAL) was tested in a beam at DESY in 2017. The setup comprised seven layers of silicon sensors. Each layer comprised four sensors, with each sensor containing an array of 256 5.5×5.5 mm2 silicon PIN diodes. The four sensors covered a total area of 18 × 18 cm and comprised a total of 1024 channels. The readout was split into a trigger line and a charge signal line. Key performance results for signal over noise for the two output lines are presented, together with a study of the uniformity of the detector response. Measurements of the response to electrons for the tungsten loaded version of the detector are also presented.

The existing CMS endcap calorimeters will be replaced with a High Granularity Calorimeter (HGCAL) for operation at the High Luminosity (HL) LHC . Radiation hardness and excellent physics performance will be achieved by utilising silicon pad sensors and SiPM-on-scintillator tiles with high longitudinal and transverse segmentation. One of the major challenges of the HL-LHC will be the high pileup environment, with interaction vertices spread not only in position, but also in time. In order to efficiently reject particles originating from pileup, precision timing information of the order of 30 ps will be of great benefit. In order to meet such performance goals, the HGCAL will provide timing measurements for individual hits with signals above 12 fC (equivalent to 3–10 MIPs), such that clusters resulting from particles with pT > 5 GeV should have a timing resolution better than 30 ps. Given the complexity and size of the system, this poses a particular challenge to the readout electronics as well as to the calibration and reconstruction procedures. We present the challenges for the front-end electronics design, results from prototype tests in laboratory and beam environments, as well as anticipated timing performance from simulation.

The High Granularity Calorimeter (HGCAL), presently being designed by the CMS collaboration to replace the CMS endcap calorimeters for the High Luminosity phase of LHC, will feature six million channels distributed over 52 longitudinal layers. The requirements for the front-end electronics are extremely challenging, including high dynamic range (0.2 fC–10 pC), low noise (∼2000 e− to be able to calibrate on single minimum ionising particles throughout the detector lifetime) and low power consumption (∼20 mW/channel), as well as the need to select and transmit trigger information with a high granularity. Exploiting the intrinsic precision-timing capabilities of silicon sensors also requires careful design of the front-end electronics as well as the whole system, particularly clock distribution. The harsh radiation environment and requirement to keep the whole detector as dense as possible will require novel solutions to the on-detector electronics layout. Processing the data from the HGCAL imposes equally large challenges on the off-detector electronics, both for the hardware and incorporated algorithms. We present an overview of the complete electronics architecture, as well as the performance of prototype components and algorithms.

The CMS Outer Hadron Calorimeter (HO) is the first large scale hadron collider detector to use SiPMs. By late January 2014 the installation of 1656 of 2376 channels was completed. The HO readout system provides for active temperature stabilization of the SiPMs to less than 0.1°C using Peltier coolers, temperature measurement, and software feedback. Each channel has independently controlled bias voltage with a resolution of 25 mV. Each SiPM is read out by 40 MHz QIE ADCs. We report on the system design, schedule and progress. The next phase for the detector is commissioning during 2014 before the 2015 LHC run. We report on the status of commissioning and plans for operation. We discuss the calibration strategy with local cosmic ray runs using the HO's self trigger ability. We discuss the plans for a global CMS operations run in November 2014.

Безградиентные методы оптимизации, или методы нулевого порядка, широко применяются в обучении нейронных сетей, обучении с подкреплением, а также в промышленных задачах, где доступны лишь значения функции в точке (работа с неаналитическими функциями).В частности, метод обратного распространения ошибки в PyTorch работает именно по этому принципу.Существует общеизвестный факт, что при компьютерных вычислениях используется эвристика чисел с плавающей точкой, и из-за этого возникает проблема конечности мантиссы.В этой работе мы, во-первых, сделали обзор наиболее популярных методов аппроксимации градиента: конечная прямая/центральная разность (FFD/FCD), покомпонентная прямая/центральная разность (FWC/CWC), прямая/центральная рандомизация на l 2 сфере (FSSG2/CFFG2); во-вторых, мы описали текущие теоретические представления шума, вносимого неточностью вычисления функции в точке: враждебный шум, случайный шум; в-третьих, мы провели серию экспериментов на часто встречающихся классах задач, таких как квадратичная задача, логистическая регрессия, SVM, чтобы попытаться определить, соответствует ли реальная природа машинного шума существующей теории.Оказалось, что в реальности (по крайней мере на тех классах задач, которые были рассмотрены в данной работе) машинный шум оказался чем-то средним между враждебным шумом и случайным, в связи с чем текущая теория о влиянии конечности мантиссы на

The relevance An analysis of scientific and technical literature in the field of development and research of aircraft engine ignition systems shows that the manifestations of resonant processes in nonlinear discharge circuits of capacitive ignition systems in the presence of two energy storage devices - a storage capacitor and an inductor coil have not been studied with the issuance of recommendations for matching the parameters of energy storage devices. This problem is of significant practical interest from the point of view of optimizing the parameters of the discharge circuits, increasing the energy efficiency and igniting ability of ignition systems. Aim of research Revealing the possibilities of increasing the efficiency of capacitive ignition systems based on the use of the manifestation of resonant processes in nonlinear discharge circuits containing two energy storage devices. Research methods Studies have been carried out involving a theoretical description of the processes during the discharge of the former charged capacitor to the R-L circuit, followed by experimental confirmation of the assumptions of the alleged states, described with the alleged resonance of occurrence in the discharge circuit using a similar falling current-voltage characteristic. Results The manifestations of resonant phenomena in a capacitive ignition system during the discharge of a capacitor on a non-linear circuit R-L are investigated. It is theoretically substantiated and experimentally proved that the dependences of the voltage in the spark discharge, the current and the energy of the discharges on the capacitance of the storage capacitor at a fixed inductance of the discharge circuit are uneven with inflection points corresponding to the equality of the inductive and capacitive resistances. It is shown that the energy efficiency of the discharge circuit can remain practically unchanged with a more than 1.5-fold decrease in the capacitance of the storage capacitor in the region of manifestation of resonant processes. The results obtained make it possible to coordinate the parameters of capacitive ignition systems, to determine the optimal values of the inductance of the discharge circuits for a given value of the capacitance of storage capacitors to ensure maximum energy efficiency and igniting capacity.

Relevance The development of new designs of electromechanical vibration transducers (EMVT) is an urgent task and is caused by the need to create devices that meet to one degree or another many, often contradictory requirements for accuracy and measurement limits, frequency range, sensitivity, overall dimensions, weight, cost, performance characteristics, etc. An important prerequisite for solving the set tasks is the study and development of new promising structural elements of electromechanical converters, materials, components, special production processes. The rapid development of science and technology causes a great variety and complexity of automatic control systems. Invariant, self-adjusting and other complex information-measuring and control systems are created, to which increased requirements are imposed. The modern development of automated monitoring and control systems for various technological and physical processes is characterized by the widespread use of primary means of collecting and processing information. At the same time, electromechanical vibration transducers EMVPsensors of vibration parameters are a link in any information-visual or control system and practically determine its metrological characteristics. Losses in the accuracy and reliability of the final result associated with unsuccessful use of the sensor cannot be restored by the most advanced information conversion system. The range of industrially produced vibration sensors is limited, and their effective operation and evaluation of experimental results is very difficult. The lack of clear recommendations for choosing one type of sensor or another, sound methods of engineering calculations and experimental studies, and analysis of limiting operational and technological capabilities has led to the fact that many types and designs of sensors turned out to be unviable. A large number of publications related to the design of new designs of vibration sensors for various purposes and the improvement of already known ones allows us to judge the continued interest of developers in this class of devices, especially with the development of technical robots and flexible modules. The lack of fundamental theory and engineering methods for calculating the static characteristics of electric motors in the mode of both a sensor and a motor with a spiral electrically conductive element limits the possibility of their rational design for information-measuring and control systems. Therefore, the tasks of researching and creating highly efficient EMVPs with a spiral secondary element that most fully satisfy the special requirements of control systems are relevant. Aim of research To investigate a vibration transducer (EMVT) with a closed spiral secondary element in the mode of generating low-frequency vibrations and improving mechanical data due to the execution of longitudinal slits with a bevel in a spiral electrically conductive spring. Research methods Literary review and patent study, methods of mathematical modeling and experimental studies of vibration oscillations. Results For the first time, a method and methodology have been developed for the design of electromechanical vibration converters with a spiral secondary element with theoretical and experimental confirmation of the main obtained positions. A full-scale sample with theoretical provisions was developed, a patent of the Russian Federation was obtained, the possibility of using a structural solution in household devices (tablets, laptops, electronic watches, nanorabototechnics, vascular medicine and cardiology, information transmission as GPS u GSM elements, etc.) was shown.

Представлены результаты численного моделирования ускорения пучка протонов при сверхинтенсивном пикосекундном лазерном воздействии на алюминиевую мишень, дающие хорошее совпадение основных параметров пучка с экспериментальными данными в широком диапазоне интенсивностей падающего излучения от $I=10^{18}$ Вт/см ${}^{2}$ до $I=10^{19}$ Вт/см ${}^{2}$ при постоянной длительности лазерного импульса. Полученные параметры пучков протонов далее были использованы для расчета полного выхода $\alpha$ -частиц и нейтронов в результате протекания ядерных реакций ${}^{11}$ B( $p,3\alpha$ ) и ${}^{11}$ B( $p,n$ ) ${}^{11}$ C при воздействии пучков протонов на борсодержащие мишени. Показано, что количество $\alpha$ -частиц, покидающих мишень из бора и способных достичь трековых детекторов, составляет не более 5 $\%$ от полного выхода $\alpha$ -частиц, поскольку бóльшая их часть задерживается в толще мишени из-за ионизационных потерь. При этом сравнение полученных расчетных значений выхода $\alpha$ -частиц, попадающих на детекторы, с экспериментальными данными показывает их достаточно хорошее соответствие. Рассчитан полный выход нейтронов в реакции ${}^{11}$ B( $p,n$ ) ${}^{11}$ C и показано, что при интенсивности $I=10^{19}$ Вт/см ${}^{2}$ пикосекундного лазерного импульса он достигает величины $N_{n}=1.4\times 10^{8}$ , что составляет около 3 $\%$ от полного выхода $\alpha$ -частиц.

We study the light output, light collection efficiency and signal timing of a variety of organic scintillators that are being considered for the upgrade of the hadronic calorimeter of the CMS detector. The experimental data are collected at the H2 test-beam area at CERN, using a 150 GeV muon beam. In particular, we investigate the usage of over-doped and green-emitting plastic scintillators, two solutions that have not been extensively considered. We present a study of the energy distribution in plastic-scintillator tiles, the hit efficiency as a function of the hit position, and a study of the signal timing for blue and green scintillators.

In this article we describe the commissioning and a first analysis of the the beam test performance of a small prototype of a highly granular silicon tungsten calorimeter. The prototype features detector elements with a channel number similar to that envisaged for e.g. the ILD Detector of the International Linear Collider (ILC). The analysis demonstrates the capability of the detector to record signals as low as 0.5 MIP. Further, no loss of performance has been observed when operating the detector in a high magnetic field.

The article considers two constructions of modern magnet cores - plate cores made of electrical steel and twisted cores made of amorphous steel. The production technologies of magnet cores with straight plate joints, oblique joints (at an angle of 45°) and on the “Step-lap” configuration are considered. The production process of a magnetic core without upper yoke is detailed. The features of the amorphous steel magnetic core assembly are given.

A group of Early-Career Researchers (ECRs) has been given a mandate from the European Committee for Future Accelerators (ECFA) to debate the topics of the current European Strategy Update (ESU) for Particle Physics and to summarise the outcome in a brief document [1]. A full-day debate with 180 delegates was held at CERN, followed by a survey collecting quantitative input. During the debate, the ECRs discussed future colliders in terms of the physics prospects, their implications for accelerator and detector technology as well as computing and software. The discussion was organised into several topic areas. From these areas two common themes were particularly highlighted by the ECRs: sociological and human aspects; and issues of the environmental impact and sustainability of our research.

For the High Luminosity LHC, the CMS collaboration made the ambitious choice of a high granularity design to replace the existing endcap calorimeters. Thousands of particles coming from the multiple interactions create showers in the calorimeters, depositing energy simultaneously in adjacent cells. The data are similar to 3D gray-scale image that should be properly reconstructed. In this paper, we investigate how to localize and identify the thousands of showers in such events with a Deep Neural Network model. This problem is well-known in the “Vision” domain, it belongs to the challenging class: “Object Detection”. Our project shares a lot of similarities with the ones treated in Industry but faces several technological challenges like the 3D treatment. We present the Mask R-CNN model which has already proven its efficiency in Industry (for 2D images). We also present the first results and our plans to extend it to tackle 3D HGCAL data.

A lot of different semiconductor converters are used in systems of generation and allocation: stations of back-to-back links and high voltage direct current transmissions (HVDC), active filters, different power sources, the grate variety of support equipment etc. All converters are treated by various effects from external circuits. It may be an over voltage at outcome due to the lightning on the HV lines or by a similar effect, it can be over current because of a short circuit mode in the load. At the other hand the converters have many internal problems depended on semiconductor devices fault or the whole shoulder breakdown. To be a converter reliable it is necessary for it to have a set of protective blocks. At this paper we give the list and a brief operating description those of them, which is considered obligatory.

В рамках представлений о пероксиде водорода как источнике фотосинтетического кислорода (водорода) рассмотрены координационные и фотохимические свойства хлорофилла и его агрегатов. С помощью квантово-химических расчетов оценены энергии связи Н 2О и Н 2О 2 с хлорофиллом и хлорофиллидом в зависимости от формы пигмента (мономеры, димеры и тримеры). Показано, что с повышением степени агрегирования пигмента энергия связи с Н 2О 2 превосходит энергию связи с Н 2О. Проведен анализ экспериментальных результатов по фотохимическому разложению пероксида водорода хлорофиллом. Сопоставлены полученные оценки термодинамических параметров (D G ° и D Н °) реакций образования органических соединений из СО 2 с водой и пероксидом водорода. Для всех рассмотренных случаев взаимодействие СО 2 с Н 2О 2 требует значительно меньших энергетических затрат, чем с водой. Методами хромато-масс-спектрометрии, Фурье-ИК-спектроскопии и химического анализа зарегистрировано образование органических продуктов (формальдегида, спиртов, карбоксил- и карбонилсодержащих соединений) с одновременным выделением О 2 под действием видимого света в системах неорганический углерод-пероксид водорода-хлорофилл (фталоцианин).

The results of development of a universal experimental stand for testing of plasma spark plugs, to investigate the stability of electric processes in the plasma spark in conditions close to the real run in different modes of current and future gas turbine engines.

The results of experimental studies of discharge processes in models of low-voltage and high-voltage capacitive ignition systems unipolar and oscillatory discharge by shooting semiconductor plugs.

Possible schemes meters of dynamic and static breakdown voltage of the plasma plug. The results of development of digital measuring the dynamic breakdown voltage meter and a combined dynamic and static breakdown voltage. Results of tests of the combined meter in conditions simulating high-altitude start gas turbine engines.

Simplified models have become a widely used and important tool to cover the more diverse phenomenology beyond constrained SUSY models. However, they come with a substantial number of caveats themselves, and great care needs to be taken when drawing conclusions from limits based on the simplified approach. To illustrate this issue with a concrete example, we examine the applicability of simplified model results to a series of full SUSY model points which all feature a small stau-LSP mass difference, and are compatible with electroweak and flavor precision observables as well as current LHC results. Various channels have been studied using the Snowmass Combined LHC detector implementation in the Delphes simulation package, as well as the Letter of Intent or Technical Design Report simulations of the ILD detector concept at the ILC. We investigated both the LHC and ILC capabilities for discovery, separation and identification of all parts of the spectrum. While parts of the spectrum would be discovered at the LHC, there is substantial room for further discoveries and property determination at the ILC.

4th Large Hadron Collider Physics Conference, LHCP2016, Lund, Sweden, 13 Jun 2016 - 18 Jun 2016 ; Proceedings of Science (LHCP2016), 149(2016).

The Phase I upgrade of the CMS Hadron Endcap Calorimeters consists of new photodetectors (Silicon Photomultipliers in place of Hybrid Photo-Diodes) and front-end electronics. The upgrade will eliminate the noise and the calibration drift of the Hybrid Photo-Diodes and enable the mitigation of the radiation damage of the scintillators and the wavelength shifting fibers with a larger spectral acceptance of the Silicon Photomultipliers. The upgrade also includes increased longitudinal segmentation of the calorimeter readout, which allows pile-up mitigation and recalibration due to depth-dependent radiation damage. As a realistic operational test, the responses of the Hadron Endcap Calorimeter wedges were calibrated with a 60Co radioactive source with upgrade electronics. The test successfully established the procedure for future source calibrations of the Hadron Endcap Calorimeters. Here we describe the instrumentation details and the operational experiences related to the sourcing test.

The second run of the LHC at the increased centre-of-mass energy of 13 TeV significantly extends the sensitivity to possible models of supersymmetry; the largest increase in cross section is expected for heavy gluino and squark pair production. Leptonic final states provide a complementary method to all-hadronic inclusive searches, while also allowing to explore more complicated SUSY scenarios. Several searches performed at the CMS experiment using the 2015 data with an integrated luminosity of 2.3 fb−1 are presented. The results are interpreted within the framework of simplified models, and allow to impose limits on a large variety of signal scenarios.

Latest results of CMS searches for a Higgs boson produced in association with top quarks in final states with tau leptons are reported.This contribution will specifically focus on technical aspects related to the Matrix Element Method implementation and on its impact on the sensitivity of the analysis.The analysis presented here uses proton-proton collision data collected at center-ofmass energies of 13 TeV during the Run II of the LHC collected by the CMS experiment in 2016.An excess has been observed with respect to the background-only hypothesis in the multilepton final states: 3.2σ observed significance (2.8σ expected).

The High Luminosity LHC (HL-LHC) will integrate 10 times more luminosity than the LHC, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry, and hallmarks the issue for future colliders.As part of its HL-LHC upgrade program, the CMS collaboration is designing a High Granularity Calorimeter to replace the existing endcap calorimeters.It features unprecedented transverse and longitudinal segmentation for both electromagnetic (ECAL) and hadronic (HCAL) compartments.This will facilitate particleflow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution.The ECAL and a large fraction of HCAL will be based on hexagonal silicon sensors of 0.5 -1 cm 2 cell size, with the remainder of the HCAL based on highly-segmented scintillators with SiPM readout.The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection.An overview of the HGCAL project will be presented, covering motivation, engineering design, readout and trigger concepts, and performance (simulated and from beam tests).

The present electromagnetic and hadronic calorimeters of the CMS experiment will be upgraded to cope with the harsh radiation environment and pileup conditions posed by the high luminosity operations of the LHC (HL-LHC) expected to start in 2027. The CMS collaboration has opted for a sampling calorimeter in the endcap sections of the detector, based on silicon and scintillator technologies, with unprecedented transverse and longitudinal segmentation to facilitate particle identification, particle-flow reconstruction and pileup rejection. As part of the ongoing development and testing phase of this High Granularity Calorimeter (HGCAL), prototypes of both the silicon and scintillator based calorimeter sections have been tested in 2018 in beams at CERN. We report on the performance of the prototype detectors in terms of stability of noise and pedestals, calibration with minimum-ionizing-particles (MIPs), and energy linearity and resolution for electrons and pions. We compare the measurements with a detailed GEANT4-based simulation.