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ISTITUTO NAZIONALE DI FISICA NUCLEARE

ELENCO PROGRAMMI PER BORSE DI STUDIO TRIMESTRALI PER LAUREANDI,

NEOLAUREATI MAGISTRALI IN FISICA DELLE PARTICELLE

O ISCRITTI AL PRIMO ANNO DEL DOTTORATO

IN FISICA DELLE PARTICELLE (Bando n. 18188 del 8 giugno 2016)

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Hosting Laboratory Available starting date Contact person(s)

CERN September 2016 Pernegger Heinz (CERN) Andreazza Attilio (INFN)

Scientific program Daily activity, skills required and to be acquired

"Studies of HV-‐CMOS sensors for the ATLAS upgrade": The High Luminosity LHC upgrade requires that the experiments will manage an interaction rate and radiation damage one order of magnitude larger than designed. In view of this upgrade the ATLAS Collaboration is exploring the use of innovative silicon pixel detectors based on HV-‐CMOS sensors, to be located close to the interaction region. The student will participate in the characterization of the first prototypes of these new detectors in testbeams, laboratory tests, transition current (TCT) measurements, as well as in the comparison of prototype performance after irradiation up to a fluence of 1016 particle/cm2. A simulation study of the impact on tracking performance can be an addition to the main characterization program.

Prerequisites for the candidate are a basic knowledge of general purpose laboratory instrumentation, interaction of radiation with matter and basic programming skills. Daily activity will be held in the ATLAS Pixel laboratory at CERN, where the student will learn advanced techniques for the characterization of silicon detectors, testing their behaviour with electrical measurements, response to laser pulses and charged particles. She or he will practice with C++ programming for the analysis of the acquired data and for the simulation of the new detector performance.

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CERN August-‐October 2016 Ancu Lucian (Univ. of Geneva-‐CERN) Volpi Guido, Alberto Annovi (INFN)


The student will join the team presently commissioning the Fast-‐Tracker (FTK) trigger processor at CERN. FTK is one of the ATLAS trigger upgrade. It will reconstruct all the inner detector tracks with transverse momentum larger than 1 GeV at the input rate of the High level trigger greatly increasing the trigger power for b-‐jet and tau-‐lepton signatures. Moreover it will allows multiple vertex reconstruction at trigger level reinforcing pile-‐up suppression strategies. FTK is based on custom electronic boards, associative memories and intensive use of FPGA. All boards are completing production. The commissioning phase in the ATLAS Control Room is in its intensive phase. We believe this is a very formative moment for a student to join the project and participate to the system commissioning. The candidate will be involved in the operation of the electronics cards, in the development of the monitoring software and the debugging of the Associative Memory board. He will study the FTK performances on the first real data and compare his results with those obtained on simulated samples. The balance of activity between operation and analysis will depend on the candidate skills and the commissioning status at the moment the student will join the project.

Month 1: participation to the commissioning and learning of basic system operations in the ATLAS online environment. Root simple plots learning the FTK format. Month 2-‐3: Monitoring software writing to control the operations of the system. Plots on the first tracks from FTK. Running of the FTK simulation to verify correct operations. If possible production of performance plots. All activities will be conducted with the supervision of experts at CERN. The required skills are: basic knowledge of C++ programming language, ROOT program and use of linux system. Basic knowledge of python programming and bash scripting language would be a plus.

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CERN August-‐November 2016 Hollar Jonathan J. (CERN) Arneodo Michele (INFN)


The CMS-‐TOTEM Precision Proton Spectrometer (CT-‐PPS) aims at studying central exclusive production (CEP) at LHC, pp-‐-‐> pXp, a process in which the protons lose a small fraction of their momentum and are measured in Roman Pot stations along the LHC beam-‐line. The reaction gives access e.g. to the so-‐called anomalous quartic gauge couplings, to the proton structure and to QCD in conditions so far unexplored. It is also possible to characterize unambiguously any resonance produced centrally and exclusively: only J^PC=0^++ or 2^++ states are possible. CT-‐PPS is currently being commissioned, a year earlier than planned, precisely in order to be able to characterize the 750 GeV resonance possibly observed in the di-‐photon invariant mass spectra by ATLAS and CMS in 2015. The fellowship recipient will take part in the commissioning and data taking of CT-‐PPS. He/she will also participate to the analysis of the data, first in order to understand the behaviour of the spectrometer, and then, if he/she so desires, to join the search for the 750 GeV state -‐-‐ or another physics analysis.

The main activities will be: participation to the CT-‐PPS work in the CMS control room; data analysis to understand the behaviour of CT-‐PPS (e.g. track multiplicities, backgrounds, correlations between the tracking and timing detectors); participation to an analysis based on the data collected with CT-‐PPS or with the data jointly collected by CMS and TOTEM in 2015. Requirements: knowledge of C++; knowledge of the CMS software environment welcome. Acquired competences: experience with near-‐beam detectors, familiarity with the physics of CEP and accelerator physics; fluency in the ROOT analysis package; most importantly, understanding of a newly installed detector and extraction of physics from its first data.

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CERN August-‐October 2016 Rovere Marco, Pantaleo Felice (CERN) Silvestris Lucia, Pompili Alex (INFN)


During Run 3, the increased luminosity with the consequent increased pile-‐up will pose significant new challenges for the CMS detector, in particular for the reconstruction of tracks that will be heavily affected by the increased track density. The quest of significantly reducing the 40 MHz data rate delivered by proton-‐proton collisions to the detectors, together with the retention of physics signal potentially interesting for searches of new physics phenomena led to the evaluation of modern multi-‐cores and many-‐cores architectures for the enhancement of the existing High-‐Level Trigger (HLT). The primary goal of the HLT is to apply a specific set of physics selection algorithms on the events read out and accept the events with the most interesting physics content. By its very nature of being a computing system, the HLT relies on technologies that have evolved extremely rapidly but that cannot rely anymore on an exponential growth of frequency guaranteed by the manufacturers. Graphics Processing Units (GPUs) are massively parallel architectures that can be programmed using extensions to the standard C and C++ languages. In a synchronous system GPUs are proved to be highly reliable and show a deterministic time response even in branch divergences. These two features allow GPUs to be perfectly suited to run pattern recognition algorithms on detector data in a trigger environment. From the physics perspective, such an enhancement of the trigger capabilities would allow inclusion of new tracking triggers and the selection of events that are currently not recorded efficiently.

The project is aimed at the development and evaluation of parallel algorithms for track seeding on GPUs. This would allow the student to learn how to program a GPU using CUDA and how to evaluate the performance of a heterogeneous computing system.

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CERN August-‐October 2016 Vai Ilaria, Maggi Marcello (CERN-‐INFN) Verwilligen Piet (INFN)


"Development and test of new Micropattern Gaseous Detectors for the muon system of the CMS experiment": The full exploitation of the LHC is the highest priority for CERN and requires a major upgrade for the LHC around 2020 (High Luminosity LHC, HL-‐LHC). In order to reconstruct precisely the proton-‐proton (pp) collisions provided by the HL-‐LHC, and maintain the high level of performance achieved during Run 1 also in the new challenging environment, the experiments have to perform a major upgrade as well. Ultra-‐fast timing detectors can identify the vertex of the pp-‐collision, thereby reducing the background from neighbouring collisions of a factor up to 200. For the upgrade of the muon system, the most promising technology are micropattern gaseous detectors (MPGD). To use timing to identify the correct pp-‐collision, detectors with sub-‐nanosecond time resolution are required. A new type of micropattern gaseous detector (MPGD) has been proposed and currently new prototypes are being produced at CERN. In the next months the activity will be focused on the analysis of the performances of these detectors, through tests in laboratory, tests beam and irradiations at facilities, in order to understand the feasibility of their installation in the CMS muon system.

The student will be involved in the activities of the CMS-‐MPGD lab at CERN. She/He will take part in the design and assembly of the new prototypes, and will characterize these detectors in the lab. The student will study the signals and detector gain with an X-‐ray gun, while a cosmic stand is available to measure the detection efficiency and the timing resolution. The student will take part in the preparation and running of detector at the test beam facilities and Gamma Irradiation Facility. Basic knowledge of radiation detection techniques for particle physics and of gaseous detectors principles is required.

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CERN September-‐October 2016 Magini Nicolò, Pierini Maurizio, Piparo Danilo (CERN) Bonacorsi Daniele (INFN)


The CMS experiment at the LHC accelerator at CERN designed and implemented a Computing model that allowed successful Computing operations in Run-‐1 and gave a crucial contribution to the discovery of the Higgs boson by the ATLAS and CMS experiments. Activities continue in Run-‐2, and an ambitious program is ahead of us, towards HL-‐LHC (2026+). Among the non-‐collisions metadata about the performances of the computing operations some well fit to deeper investigation with Big Data Analytics (BDA) approaches. Exploratory projects to extract value from this dataset, e.g. by investigating predictability of crucial metrics, as well as seeking for far-‐from-‐obvious patterns and correlations, can get a big value out of this dataset. One aspect of particular interest in this context is the CMS data access pattern in distributed analysis (modelled as the “data popularity” metric): this is the basis to design more intelligent and fully automated dynamic data placement systems, and achieve large optimisation in the storage usage at all Tiers levels. CMS experts designed and developed a prototype infrastructure based on supervised machine learning, and ad-‐hoc hardware resources are being acquired for the task. We propose to exploit such resources to apply supervised ML techniques on monitoring data extracted from CMS databases and prepared for the task, and to study the data popularity of CMS data in the past in order to predict the data popularity of new data.

The student will be introduced to the challenging topic and to the existing prototype, and will work on completing the implementation and on performing the tests towards an actual predictability of popularity based on past data. The project requires familiarity with the Linux OS and environment, interest in computing technologies and (if possible) some pre-‐existing knowledge about python and Machine Learning.

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CERN August-‐October 2016 Iengo Paolo, Sekhniaidze Givi (CERN), Alviggi M.Grazia (INFN)


The ATLAS collaboration is presently involved in the detector upgrade for LHC phase 1. Part of the Italian ATLAS-‐muon community (Cosenza, Lecce, Napoli, LNF, Pavia, Roma1, Roma3) is taking care of building one (SM1) of the four types (SM1,SM2,LM1,LM2) of MicroMegas modules needed for the New Small Wheels of the muon spectrometer. Other ATLAS institutions (CERN, Dubna, Thessaloniki, Germany, Saclay) will take care of the remaining three module types. The first module, named Module 0 in the following, has recently been built from the Italian community, and other three, one for each type, will come from the other involved institutions in the next few months. These Modules 0 will be right after brought to CERN, in order to be tested with both cosmics and charged particles beams before starting the full production. These tests will be aimed at studying the Modules 0 performance with particular attention to the track reconstruction capability, that is the micromegas main task in ATLAS. After the 'testbeam' periods, we also plan to bring at least one of the Modules 0 to the Gamma Irradiation Facility (GIF++, CERN) in order to study its high rate performance and ageing.

Depending on the starting date of the fellowship, she/he would be involved in one (or two) of the foreseen activities, 'cosmics and test beam' or 'GIF++', participating to the setting up of the needed instrumentation, to the data taking and to the data analysis. Knowledge of C++ and Root would be an advantage but not mandatory. The student will have the opportunity to acquire hands-‐on experience on: • micromegas detectors, • readout electronics and acquisition packages, • particle physics data analysis tools, • 'handling' of a small scale experiment.

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CERN September 2016 Petyt David A. (RAL), Di Marco Emanuele (CERN), Rahatlou Shahram (INFN)


The electromagnetic calorimeter (ECAL) of the Compact Muon Solenoid (CMS) Experiment is crucial for achieving high resolution measurements of electrons and photons. Maintaining and possibly improving the excellent performance achieved in Run I is vital in searches for new heavy resonances. In particular, the optimal ECAL energy resolution is of paramount importance and a necessary ingredient to verify the modest excess in the di-‐photon invariant mass at 750 GeV, observed by both ATLAS and CMS collaborations, with the data to be collected in 2016. The project is focused on the calibration of the ECAL with pi0 and eta mesons decaying into a pair of photons, which is the most precise technique to achieve the ECAL energy crystal-‐to-‐crystal calibration with the first data collected at 13 TeV center-‐of-‐mass energy in 2016. The method has to be optimised for the LHC bunch spacing of 25 ns, and for the instantaneous luminosity that during 2016 is expected to exceed the levels previously attained. The average number of concurrent proton-‐proton collisions per bunch-‐crossing is expected to reach up to 40 interactions, thus challenging the calibration with low pT photons from pi0/eta decays. The student will need first to optimise the rates of the CMS High Level Trigger (HLT) π0/η stream. The HLT is responsible for selecting interesting events to be recorded and is based on different dedicated streams used for physics analyses or calibrations. Then the student will perform the calibration with data.

This requires technical skills in C++, python, and a preliminary knowledge of the CMS software (CMSSW). For the calibration part of the project, the student will be provided with ROOT trees from the dedicated calibration streams, and will need to perform efficiently a large number of fits on large datasets. This requires skills with python, C++, ROOT and RooFit. The student will learn basic concepts of calorimetry, in-‐situ calibrations of an extremely precise detector, basic concepts of data analysis and also computing.

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CERN August-‐October 2016 Arcidiacono Roberta (CERN/INFN) Nicolò Cartiglia (INFN)


We propose a stage of 3 months at the silicon lab. of dott. M.Moll at CERN. Moll's lab. is at the forefront in the research of new type of silicon sensors, and it has an extremely advanced array of measuring set-‐up. Making a stage in this lab. is a very important step in the education of a student interested in the development of new detectors. In Moll's lab. they measure key features of silicon sensors such as the IV and CV curves, and the test with laser sources, to reproduce the signals generated by minimum ionizing and alpha particles. They are currently also very engaged in the study of radiation damage of silicon sensors in view of the productions on the silicon detectors for HL-‐LHC. Finally, they use full simulation packages for particle detectors such as TCAD Synopsis, offering the prospect student the possibility to learn such advanced tool. An added benefit to a stage in Moll's lab. is the wide range of scientific contacts, as this is the centre of the CERN RD50 collaboration whose goal is the development of silicon detectors for future experiments.

The student will learn how to program instruments (Labview, mathlab) and perform accurate testing of semiconductor sensors in a laboratory. He/she will also participate in beam test activities, and the subsequent data analysis (root, C++). He/she will learn the basic principles of TCAD simulation and at the end of the stage will be able to compare the behavior of silicon sensors with the predictions from simulation (Synopsis).

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CERN August 22, 2016 Lamanna Gianluca, Spadaro Tommaso (CERN/INFN)


"Photon-‐based new-‐physics searches at NA62": The scientific activity will be performed within NA62, a ultra-‐high-‐intensity kaon-‐beam experiment operating at the CERN SPS. It will focus on the high-‐efficiency large-‐angle veto calorimeter (LAV) build by the NA62 Frascati group. In particular, advanced methods for efficiency assessment will be developed, based on unbinned maximum-‐likelihood kinematic fits and/or machine-‐learning techniques for selection of high-‐purity control samples. A thorough knowledge of the calorimeter efficiency to photons will allow exploitation of high-‐intensity kaon and pi0 tagged beams for high-‐sensitivity searches of new physics beyond the Standard Model, based on real data acquired in 2016. We propose a search for K+ decays producing final states with a single charged pion and a single photon, which can reach unprecedented sensitivity on certain dark-‐matter candidates known as dark photons.

The candidate is expected to be familiar with basic concepts of kinematics of particle decays and the observables provided by a modern high-‐energy-‐physics detector: the momentum measurement from a magnetic spectrometer; the energy deposit, the position and time of impact from electromagnetic and hadronic calorimeters, the particle-‐identification provided by ring-‐imaging and differential Cherenkov counters. Basic code development capabilities in C++ and ROOT are mandatory. Under the day-‐by-‐day guidance of the reference researchers, he/she will develop and follow a programme to: i) precisely assess the calorimeter efficiency to be applied for a new-‐physics search comparing selected control samples on data and Monte Carlo; ii) evaluate the efficiency of a simple algorithm for selection of new-‐physics decays with a dark photon in the final state; iii) evaluate the expected background from data side-‐bands and Monte Carlo. After a three-‐month experience, he/she will have gained familiarity with modern methods for efficiency evaluation, systematic error assessment and background evaluation.

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CERN September-‐October 2016 Borghi Silvia (CERN) Grillo Lucia, Marta Calvi (INFN)


The LHCb experiment performs precision measurements in beauty and charm meson sectors, potentially sensitive to physics beyond the Standard Model. The new scheme for the LHCb software trigger in Run-‐II allows to perform alignment and calibration in real-‐time. This novel strategy is a key ingredient to allow the offline-‐quality event reconstruction to be performed in the trigger, where tighter requirements are applied increasing the selection efficiency and purity of the samples. This concept leads to considerable gains in physics performances, but there is still room for further improvements. The alignment of the tracking system could be improved exploiting additional constraints and a better selection of the tracks and particles used in the procedure. For example the residual information defined as spatial or time distance between the measured hit position and the predicted one by the track extrapolation, could be further exploited to discriminate tracks of real particles from fakes. The new selection criteria need to be studied, tuned verifying the results of the alignment quality, and implemented in the trigger selection. Depending on the signal efficiency and background rejection achieved, the selection could have additional use cases. The student will develop these procedures collaborating with tracking, alignment and trigger experts.

The student should be able to understand and modify the indicated part of code (mainly C++ and python), and have some physics knowledge/understanding. It is desirable some knowledge of the ROOT framework and multivariate analysis tools. This project allows the student to familiarize with detector alignment and calibration procedures and the trigger system, which are the fundamental key ingredients of any experiment in High Energy physics, and to gain/increase experience in data analysis and computational algorithm development.

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CERN October 2016 Alessio Federico (CERN) Baldini Wander (CERN/INFN)


"The upgrade of the LHCb MUON Detector Control System": During the Long Shutdown 2 (LS2) the LHCb detector will be upgraded to allow the efficient operation of the experiment at an instantaneous luminosity five times higher with respect to the current conditions. Both the upgraded detector readout, the readout control system and ECS (Experiment Control System) will use custom FPGA-‐based PCIe boards allowing bidirectional optical-‐link communication with the front-‐end electronics, with specific subdetector's firmware developed on top of a common framework. For what concerns the ECS this new architecture will allow having a much increased bandwidth compared to the current one, allowing a faster detector configuration and much improved monitoring capabilities. This will be done through the use of a common developed firmware, which satisfies all the sub-‐detector's specific requirements and a common software framework, based on WinCCOA. The boards used for the ECS are called SOL40 and allow both a fast control (timing) and slow control (detector configuration and monitoring) capabilities.

The three months project we are presenting here will be dedicated to the development of the muon detector specific part of the new ECS. The successful candidate will initially work, in collaboration with the LHCb CERN experts on the development of the general software/firmware infrastructure with the goal of allowing the write (detector configuration) and read (detector monitoring) operations on the MUON detector front-‐end electronics. This first part will entail acquiring the necessary knowledge of the software/firmware framework currently in use within the upgrade, the development of a first test project and the development of the MUON specific requirements to be integrated within the global framework. In the second part of this project the candidate will work on the development of the muon-‐specific part of the ECS that will allow, at the conclusion of the project, the first readout and control tests of the new muon readout (nODE) and detector control (nSB) boards which are currently in preparation.

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CERN August-‐September 2016 Micheli Francesco (CERN) Cavallari Francesca (CERN/INFN)


"Beam test for the upgrade of the electromagnetic calorimeter of the CMS experiment at CERN": The Large Hadron Collider at CERN is the world's largest and most powerful particle collider. To extend its discovery potential, the LHC will need a major upgrade, after 2022, to increase its luminosity (rate of collisions) by a factor of 10 beyond the original design value (from 300 to 3000 fb-‐1). This new high-‐luminosity phase of LHC (HL-‐LHC) will pose stringent requirements on detector characteristics given the high pile-‐up, the high rates of radiation and energetic particle fluence. In particular, the identification and momentum measurement of high-‐energy photons and electrons will be particularly challenging for the actual calorimetric systems of LHC experiments. Since these particles are crucial for measuring Higgs boson properties and to discover new particle beyond Standard Model predictions, the CMS experiment is planning an upgrade of its Electromagnetic calorimeter (ECAL) to improve its performance in such adverse experimental conditions. This upgrade effort will focus on the development of new technologies and solutions to mitigate the effects of the increased pile-‐up. In this context, several beam tests will take place at CERN SPS beam line. New components and new possible crystal-‐based technologies will be thoroughly studied looking at their response to a beam of high-‐energy electrons up to 200 GeV. The selected student will take part to the preparation of the experimental setups, to data acquisition at the SPS beam line and the data analysis of the collected data.

The selected student will take part to the different phases of a test-‐beam: building of the experimental setup, data taking and data analysis. This will include hardware work in the lab or in the SPS beam line and the writing of software for data taking and data analysis. A basic knowledge of C++ programming and ROOT software is needed. Basic knowledge of electronic technologies commonly used in experimental physics are required. At the end of the experience the student will acquire a full expertise in setting up and testing a new R&D project, with advanced skills in both hardware and software field.

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CERN August-‐October 2016 Cavaliere Viviana (CERN) Roda Chiara (INFN)


LHC data allows a very wide search for new physics and being in an historical moment in which a clear direction on where to search is not available it is very important to exploit at best all the potentiality of the acquired data sample. Searches for resonance in massive vector bosons with hadronic decays have recently started to exploit boosted signatures reconstructing the high pT hadronically decaying boson as a single large jet (jet radius ~1) and using the large jet sub-‐structure to identify those jets consistent with a two prong decay. In this project we want to explore the possibility to use micro-‐jets (let radius ~0.2) in conjunction with track-‐jets to better exploit these signatures. The high segmentation of the electromagnetic calorimeter section, which collects about 60% of the jet energy, should allow to simplify and empower the search for these boosted objects. This study will start in a simplified scheme using truth jets to start comparing the performance of the micro-‐jet to those of the large jet. It will then evolve to include detector effects. We will use Graviton or W' decaying to WW/WZ as benchmark signals. The performance of the reconstruction will be judged based on signal efficiency, rejection power and mass resolution.

Month 1: learning data format and content of root-‐ples to be used for the analysis, reproduce simple results to understand the context of the problem. Month 2: Studies on large and micro jets at truth level (no detector effects) for signal and background processes. Month 3: Include detector effects. All activities will be conducted with the supervision of experts at CERN. The required skills are: basic knowledge of C++ programming language, use of a linux system and knowledge of the ROOT program. Basic knowledge of python programming language and bash scripting language would be a plus.

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CERN September-‐November 2016 Tosi Mia (CERN) Dall'Osso Martino, Dorigo Tommaso (INFN)


“Search for Anomalous Double Higgs Production with CMS”: The program foresees the analysis of Run 2 data collected by the CMS experiment in the search for pair production of Higgs bosons, a rare process in the SM (σ(SM, 13 TeV)=38 fb) which could however be strongly enhanced by anomalous values of five couplings whose value is at the time of writing not well constrained by direct measurement. The group searches for the HH→bbbb final state in multijet data. Due to its large branching fraction this is the most sensitive search channel. The group foresees to produce a limit to SM production in August; thereafter, with the help of the student, we will recast the search (by a full re-‐optimization of the analysis procedure) to exclude regions of the parameter space of the anomalous couplings, by considering 12 benchmarks as defined in a recent publication (A.Carvalho et al., “Higgs pair production: choosing benchmarks with cluster analysis”, J.Inst. 2016 (4) 1-‐28). The recasting will involve a tuning of the BDT classifier to account for the kinematical properties of the considered benchmarks and a study of how the extracted limits propagate to the full 5-‐dimensional space of model parameters.

The trainee will be closely followed in daily research activities by the mentor (M. Tosi). He/she will identify, for each benchmark model, the most promising kinematical variables to discriminate the signal; then train a BDT classifier and optimize it; re-‐run the fit to extract limits; and finally extrapolate results to the full model space. In this activity the trainee will cooperate tightly with the other group members. During the first two weeks he/she will be trained to train and test the classifier. In the following two months the trainee will optimize the classification for the 12 benchmarks. The last period of internship will be spent to extract limits on model parameters. The initial competences required are familiarity with C++ and root (python welcome). After the training the student will be at ease with multivariate analysis applications to high-‐energy physics problems.

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FERMILAB August-‐December 2016 Gecse Zoltan (FNAL) Meridiani Paolo (INFN)


"The CMS High Granularity Calorimeter at the High-‐Luminosity LHC": The discovery of a Higgs boson by the CMS and ATLAS Collaborations represents a defining moment in the history of science. Nevertheless there are still fascinating open questions in particle physics: what is the nature of the Dark Matter in the Universe? Are there extra dimensions of space-‐time? Why there is more matter than antimatter in the Universe? In fact the exploration of phenomena beyond the Standard Model has just started. To achieve sensitivity to rare processes, the LHC will be upgraded and operated till ~2035. The upgrade will allow the machine to achieve instantaneous luminosities ~7 times larger than the nominal one. To cope with the unprecedented collision rate with up to 200 collisions per bunch-‐crossing, the CMS end-‐cap calorimeter will be upgraded. The new detector is referred to as High Granularity Calorimeter (HGCAL) and has an innovative design using silicon sensors as active material. The HGCAL will allow reconstruction of particles with unprecedented spatial resolution. It will also provide timing information that will be used to identify the interesting physics collision among the ~200 overlapping ones. Fermilab is currently contributing to the R&D of the project and will participate in the construction of the detector during the production phase.

The student will work in close collaboration with post-‐doctoral researchers and scientists at Fermilab within the CMS collaboration. The work will consist of electrical and mechanical studies of the prototype modules being built at Fermilab. For example, the student will use a dedicated station to characterize the silicon sensors, test modules, and will participate in the development of the data acquisition system. The student will learn the fundamentals of detector physics, electronics, and data-‐acquisition systems. The student will use the laboratory instrumentation including oscilloscopes, power supplies, LCRs, etc. The software to control the instruments is mainly developed using the C++ language and Labview. Experience with object-‐oriented programming and electronics would be an asset.

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FERMILAB August-‐September 2016 Uplegger Lorenzo, Rivera Ryan (FNAL) Moroni Luigi (INFN)


The aim of this project is the final set up and commissioning of the new telescope of silicon microstrip detectors for beam track reconstruction at the Fermilab Test Beam Facility. The new telescope, which will replace the old one made of CMS pixel detectors, consists of an array of 14 planes, each with 640 strips with a length of 9 cm and 60 mm pitch. This upgrade will allow for a wider acceptance, 3.84 x 3.84 cm2, and a smaller error on the track extrapolation at the detector-‐under-‐test-‐position, ≈ 5 mm. These improvements of the tracking performance will be instrumental for the characterization of the next generation of pixel detectors, which are now under development for the future High Luminosity phase of LHC.

The activity required to complete this project is well suited for an initial training of a master's student in the field of the experimental high-‐energy physics. Starting from the precise timing of the trigger, the data acquisition and the event builder should be debugged, the track reconstruction precision properly checked and finally a detector-‐under-‐test, consisting of a pixel detector, fully characterized. The basic daily activity will therefore consists of code debugging and analysis of the detector performance. Knowledge of the present generation CMS pixel detectors and some experience with them is required.

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FERMILAB October-‐December 2016 Murat Pavel (FNAL) Di Falco Stefano (INFN)


"Analysis of the Mu2e calorimeter prototype test beam and corresponding improvement of the calorimeter simulation and analysis tool": The Mu2e experiment at Fermilab aims to discover the Charged Lepton Flavor Violation (CLFV) by improving by 4 orders of magnitude the current experimental sensitivity for a muon conversion to an electron in a muonic atom. A positive signal could not been explained in the framework of the current Standard Model of particle interactions and would be a clear indication of new physics. During its 3 years of data taking, Mu2e is expected to observe less than one background event mimicking the electron coming from the muon conversion. Such level of background suppression requires a deep knowledge of the experimental apparatus: a straw tube tracker measuring the electron momentum and time, a cosmic ray veto system rejecting most of the cosmic background and a crystal calorimeter that will measure the time of arrival, the energy and the impact position of the converted electron. The current estimate of the background level is based on the Monte Carlo simulation of the experiment. In the fall 2016 a test beam of a reduced scale prototype of the calorimeter will be performed: its results will be used to validate and improve the Monte Carlo simulation and the selection algorithms based on it.

The student is required to start having a basic ability of C++ programming, an optional knowledge of ’root’ analysis program and an academic knowledge of particle detectors. During his/her stay at Fermilab he/she will learn to use the ’mu2eart’ framework used for the simulation and the analysis of the Mu2e experiment. He/she will participate to the Mu2e weekly meetings to learn about the state of the art of the experiment. He/she will contribute to improve the calorimeter simulation and analysis tools, in the light of the calorimeter test beam results, to enhance the confidence level for the candidate conversion electrons.

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FERMILAB August 2016 Ferrari Carlo (FNAL) Venanzoni Graziano (INFN)


The subject of this research program is the calibration system of the Muon g-‐2 experiment at Fermilab. The aim of the calibration system is to monitor the SiPM gain fluctuations with relative accuracy at sub-‐per mil level to achieve the goal of keeping the systematics contributions to the accuracy on the measured observables at 0.02 ppm level. This is a challenge for the design of the calibration system because the desired accuracy is at least one order of magnitude higher than that of all other existing, or adopted in the past, calibration systems for calorimetry in particle physics. The work will consist in the construction and testing of the system under the supervision of Dr. Carlo Ferrari at Fermilab. The calibration system is made of six lasers operated in pulsed mode (405 nm, 1000pj / pulse, 10 kHz rate), with source monitor double calibration (Laser and Am source) as a reference. A second monitor device will control the chain of laser pulses to the 1330 SIPM placed in the 24 calorimeters along the ring. The distribution system will be placed in a Laser Hut, close to the g-‐2 ring. The successful candidate will contribute to the installation and assembly of the whole system.

The program is a three-‐month stay at Fermilab, from August to October, consisting of three phases: August: Step 1) Laser Hut commissioning: The laser distribution system will be installed in the laser Hut; September: Phase 2) Assembly of the calorimeters: Each of the 24 calorimeter will be assembled with the front panel of the calibration system October: Step 3) Calorimeter Installation in the ring: each calorimeter with his front panel will be installed in the g-‐2 ring and connected with the laser distribution system from the Laser Hut. General confidence with particle detectors and a skill towards hardware activities is a pre-‐requisite of this research program. At the end of the program the student will have the experience of participating in the realization and commissioning of a modern elementary particles experiment

KEK-1


KEK September 2016 Gaz Alessandro, Matsuoka Kodai (KEK) Torassa Ezio, Tamponi Umberto (INFN)


"Commissioning of the TOP detector at Belle II with cosmic ray data": The TOP (time of propagation) is the Belle II detector devoted to particle identification in the barrel region. It has been fully installed in May 2016, while the main tracking device, the CDC (central drift chamber) will be installed in August 2016. In the Fall of 2016, most of Belle II sub-‐detectors will be installed and operational, and an intense phase of commissioning with cosmic ray data will begin. Precise tracking will be provided by the CDC, while trigger inputs will be provided by the ECL (electromagnetic calorimeter) and the KLM (detector of KL's and muons). All the installed TOP modules will be tested and characterized with cosmic rays and with the laser calibration system and their performance will be compared to the design expectations. Along that, a test stand will be set up to operate a spare TOP module. This will be used to monitor the long-‐term stability of the components and test and develop new firmware and data acquisition software.

The student will work, with the help of tutors, on the setup of the testing area. He/she will also acquire data, analyze them with specific software, and look at the results. The student will learn how to customize the data acquisition system and the analysis procedure, depending on the purpose of the specific test. The required skills are basic knowledge of the UNIX operating system and some familiarity with NIM hardware. Some experience with the ROOT analysis software is desirable. Program of study or thesis in experimental high energy physics is preferred.

KEK-2


KEK September 2016 Nakamura K.R. (KEK) Forti Francesco (INFN)


"Installation of the modules of the Belle-‐II Silicon Vertex Detector ": A Silicon Vertex Detector (SVD) is the central part of the tracking system of the Belle II experiment, crucial to perform a precise measurement of the position of the decay vertices, with the capability of reconstruction of low momentum tracks. The SVD is composed of four layers of 300 um-‐thick double-‐sided silicon strip detectors (DSSD), covering the polar angle from 17 to 150 degrees and radius from 39 to 135 mm. Slanted trapezoidal sensors are used in the forward region to minimize the instrumented surface while still covering the largest angle, featuring modules with a peculiar lantern shape. The ladder design, the support structures and the evaporative CO_2 cooling system have been optimized to get a very low material budget. The installation of the SVD modules on the support cones presents several challenging aspects: due to the small clearance between the layers, precise mechanical tools have been developed for safely mounting the modules by preventing any mechanical stress; the position of modules must be surveyed to be used as input for the alignment procedure; extensive tests for the electrical characterization are performed to assess that each ladder retains its high performance in its final position on the whole support structure.

The student will work, inside a team of experts and assisted by a tutor, on the setup of the mechanical tools and on the optimization of the procedures needed for ladder mounting. He/she will perform the electrical characterization of the ladders before and after mounting, by using a test-‐stand equipped with the final DAQ system of the experiment. Data will be analyzed to perform a comparison with the results obtained soon after the ladder construction. The required skills are basic knowledge of the most popular operating systems. Some experience with the ROOT analysis software is desirable. Program of study or thesis in experimental high-‐energy physics is preferred.

TRIUMF-1


TRIUMF September 2016 Hessey Nigel, Stelzer-‐Chilton Oliver (TRIUMF) Cobal Marina (INFN)


After the discovery of a Higgs boson at the LHC, a so-‐called Phase 2 upgrade has been proposed to enable the LHC to operate at instantaneous luminosities of 5-‐7E34 1/cm2/s and to provide up to 3000/fb of data by around 2035. To take advantage of the unique discovery potential of the high luminosity LHC, the current ATLAS inner tracking detector must be replaced. The conceptual design of a new all-‐silicon tracker (ITK) is based on 4 3D pixel and 5 strip barrel layers as well as 6 pixel and 7 strip disks on each side of the ATLAS interaction point.

Contribute to prototype production of ATLAS silicon strip detector modules using fully automatic wire bonder; Setup of UV curing of module assembly; ITK module QC/QA; Contribute to module placement setup with automatic gantry; Analyze and characterize detector signals of new ITK modules; Test performance, data taking in high radiation environment. Silicon detector operation and trouble shooting -‐ High performance wire bonding -‐ Knowledge of experimental challenges related to particle physics -‐ Detector readout and data acquisition systems -‐ Data analysis in experimental particle physics

TRIUMF-2


TRIUMF August-‐December 2016 Retiere Fabrice, Doria Luca (TRIUMF) Collazuol GianMaria (INFN)


Nowadays particle physics aims at unravelling the most fundamental constituents of matter. Modern experiments rely on cutting-‐edge technology for particle detection with unprecedented resolution. This project represents an excellent opportunity for dealing with advanced detector technology based on novel silicon photo-‐multipliers (SiPM). In particular, applications include accelerator-‐based experiments like NA62 at CERN (calorimeter and RICH detector upgrades) as well as astro-‐particle physics experiments such as nEXO at SNOlab. The project involves the development of novel SiPMs for particle physics applications requiring photo-‐sensitive areas larger than 10mm2. The Fondazione Bruno Kessler (FBK, Trento -‐ Italy) recently produced new 1x1cm2 SiPMs sensitive all the way down to vacuum ultra-‐violet wavelengths. These new SiPMs will be delivered to TRIUMF in June 2016. They have to be fully characterized including measuring their efficiency from 170nm to 600nm, their dark noise and correlated avalanche rates from room temperature to -‐100C. In addition, a dedicated electronics system will be required to keep the electronics noise well below one photo-‐electron equivalent.

The student will be responsible for the characterization of the 1x1cm2 SiPMs from FBK using the characterization setup at TRIUMF. The setup has already been used for testing other SiPMs. However, so far only smaller (3x3 or 6x6mm2) SiPMs have been tested and the new challenge will be in the electronics system. The student is not expected to develop the electronics but as the primary user, he/she will work on the characterization of the electronics performances possibly requesting improvements. The end goal of the project is a draft paper outlining the performances of the new FBK SiPM. The student will be encouraged to contribute in writing the paper. Summary of knowledge acquired during the project: Particle detectors and photo-‐detectors, including solid-‐state physics. Laboratory skills (operation of various instruments). Low noise analog electronics. Programming, in particular waveform processing.

TRIUMF-3


TRIUMF August-‐November 2016 Fujiwara Makoto C., Amaudruz Pierre (TRIUMF) Stracka Simone (INFN)


The ALPHA/AD-‐5 experiment (Antihydrogen Laser PHysics Apparatus) at CERN's AD is a leading experiment in the study of confined antihydrogen (atomic state of antiproton and positron). The ALPHA group in TRIUMF applies particle physics techniques to the characterization of the spectroscopic and gravitational properties of antimatter, aiming to tests of CPT and of the weak equivalence principle by means of a precise comparison with hydrogen. At present, ALPHA primarily relies on a silicon-‐strip barrel detector for imaging the main signatures in the experiment, i.e., antihydrogen annihilation events occurring in a ~30 cm long confinement region. In the near future, the confinement region will be extended considerably to allow for the systematic study of the gravitational behaviour of antihydrogen, and the silicon detector will be replaced with a 2-‐m long time projection chamber (TPC) which is currently being designed at TRIUMF. A first prototype and the associated DAQ system are being built starting in summer 2016. The student will join the TRIUMF group in Vancouver (Canada) and participate in several aspects of TPC design and prototyping work. In particular he/she will contribute to the DAQ and particle tracking software. Analysis of data collected by the ALPHA experiment is also possible.

The student collaborates in developing the prototype's DAQ system and analysis software. He/she participates in data taking with the prototype detector, and helps optimize the signal processing of raw data, to develop strategies for the full-‐size TPC. Depending on her/his interests, she/he then either characterizes the performances of event-‐reconstruction algorithms -‐exploring possible improvements in resolution,-‐ or studies applications of machine-‐learning techniques to the analysis of simulated events and real data from current apparatus. He/she can also participate in the construction of the full-‐size TPC, gaining hardware experience. Recommended skills: Unix, C++, ROOT. Acquired skills: DAQ (MIDAS), VHDL, GEANT4, data analysis.

TRIUMF-4


TRIUMF September-‐October 2016 Marchetto Marco (TRIUMF), Zotto Pierluigi (INFN)


The new ARIEL facility at TRIUMF includes a high resolution separator (HRS) for the selection of rare isotope beams (RIB). The resolving power depends, among other factors, on the quality of the magnetic field integral within the so-‐ called good field region (the area of the magnet where the beam will travel and where the field must be of the highest quality). Specifically the longitudinal field integral has to be within few parts per millions for different trajectories. A magnet that satisfies the ARIEL HRS field integral requirements has been designed and it is now in the fabrication stage. Once the magnet is built, it needs to be characterized by measuring the integral field. Current methods using a Hall or a NMR probe cannot yield the desire result. A Hall probe can only achieve a resolution of 10-‐4, while a NRM, even though capable of achieving 10-‐6, can only operate in a region of uniform field hindering from the possibility of characterizing the fringe field of the magnet. Such a measurement requires therefore the development of a dedicated apparatus and measurement technique. A proof of principle has already been established but further development is necessary to reach the desired accuracy. The goal is to define the final apparatus before the HRS magnet is delivered to TRIUMF (expected early 2017).

The candidate will be required to interact on a daily basis with the beam physics group in the accelerator division as well as the various group in the engineering division such as Control, Electronics, Mechanical and Design Office. The candidate will become familiar with the magnetic field simulation code OPERA®, the reference code in the field, and potentially with other 3D design codes such as SOLIDWORKS®. Hands on skills are expected since the candidate will have to set up the apparatus and conduct the integral field measurements. The measurement results will have to be interpreted and presented during the weekly beam physics group meeting for discussion so the candidate will have to demonstrate analysis and communication abilities. A final report is expected. The project should consolidate the candidate knowledge in experimental physics, magnetic field simulations, and data analysis.

istituto nazionale di fisica nucleare mae/elenco_25programmi_finali_csn1.pdf · istituto nazionale...

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