Foto del docente

Eugenio Scapparone

Adjunct Professor

Department of Physics and Astronomy

Curriculum vitae

Eugenio Scapparone Curriculum vitae

 

Education

 

1990: degree in Physics, summa cum laude, at Universita' degli Studi di Bologna;

1995: Ph. D. in Physics at Universita' degli Studi di Bologna.

 

Fellowship

 

1989: wins the competition for a INFN fellowship at LNGS for undergraduate students

          (1st classified);

1991: wins the competition for the Ph. D. admission, both at Firenze University

          (1st classified) and at Bologna University, choosing the last one;

1993: wins the competition for a permanent staff researcher position at INFN - LNGS

          (1st classified).

2010: wins the competition for a permanent “Primo Ricercatore” staff researcher position at

          INFN - Bologna

 

Experiment and Laboratory Responsibility

 

1995-1997: Coordinator of the “Data Storing Group” of the MACRO experiment;

1997-1998: Run Coordinator of the MACRO experiment;

1997-1999: LNGS responsible of the NOE-TEST R&D (SciFi calorimeter);

1995-2001: Responsible of the LNGS GPS clock;

2008-2011: ALICE Deputy Commissioning Coordinator;

2010-2011: ALICE Ultra Peripheral Collision PAG (Physics Analysis Group) co- 

                    Coordinator (with J. Nystrand, Bergen University);

Since 2012: Co-convenor of the ALICE PWG-UD (PWG= PhysicsWorking Group,  

                    UD= Ultra peripheral and Diffractive Physics) with J.P. Revol(CERN).

Since 2012: Member of the ALICE Physics Board.

 

Committee

 

1998-2001: Member of the INFN Computing Committee;

2001: In the EU 5th Framework is Scientific coordinator of the TARI project

          (Transnational Access to Research Infrastructure);

2004-2007: In the EU 6th Framework is nominated member of the User Selection

          Panel of ILIAS (Integrated Large Infrastructure for Astroparticle Physics),  

          whose members are the Directors of the four European underground  

          Laboratories and four selected members; 

1999-2007: referee for the journals Astroparticle Physics and European Physics   

           Journal C

Since 2009: member of the INFN 3rd Scientific National Committee.

 

Teaching experience

 

Although the INFN staff researchers are not required to teach, ES was:

1999: Contract Professor at  Università degli Studi dell'Aquila :

          “Experimental methods in elementary particle physics“, 20 lectures.

2000: Contract Professor at Università degli Studi di Bologna, at Ph.D courses:

          “Physics at LNGS”, 4 lectures.

2001:     Contract Professor at Università degli Studi dell'Aquila:

             “Principles of particle physics detectors and accelerators”, 20 lectures.

2007-2011: Contract Professor at Universita' degli Studi di Bologna:   

                  “Advanced experimental methods in particle and astroparticle physics”,

                  20 lectures;

2010-2011: “Quark gluon plasm physics” at at Universita' degli Studi di Bologna,

                   dottorato di ricerca” , 4 lectures.

          • 150 published papers;

          • 30 talks at International Conferences (6 by invitation);

 

                                                                                                                                                           

Research activity

 

 The research activity of Eugenio Scapparone (ES) included three lines:

 

1)     Heavy ion physics with the ALICE experiment  (2002-2007);

2)     Neutrino oscillation physics at LNGS (1995-2001);

3)     Cosmic ray physics with the MACRO experiment (1990-1995).

 

 

1) HEAVY ION PHYSICS WITH THE ALICE EXPERIMENT

 

 

  In 2002 ES moved from LNGS to Sezione INFN di Bologna, where he joined the ALICE – TOF collaboration, aiming to construct a detector, based on RPC multigap (MRPC), with a time resolution  s < 100 ps, on a ~150 m2  area, segmented in about 160,000 pads. Such precision, folded with the high segmentation, will allow the identification of the charged particles with 0.5 GeV/c < p < 2.5 GeV/c, produced in the interaction.

 

The personal contribution of the candidate spans three different activities:

a)     Responsibility of the  “trigger” system based on the TOF;

b)     Responsibility of the TOF High Voltage system;

c)     Study of the gas mixture to optimize the detector performances.

 

 

a)  The L0/L1 trigger based on ALICE-TOF

 

 

ES has the full responsibility of the TOF trigger system, aiming to select events originated by Pb-Pb and p-p interactions, and cosmic muons. This trigger provides L0/L1 signals to the ALICE CTP (Central Trigger Processor) for p-p minimum bias, Pb- Pb high multiplicity and Ultra Peripheral Collision, and cosmic events.

   The candidate designed and constructed a system based on two layers. The first one is made of 72 VME boards, called LTM (Local Trigger Module), inserted in the VME crates placed in the neighbourhood of the detector. Each LTM receives from the front end cards (FEAC) 48 LVDS (Low Voltage Differential Signaling) signals, each obtained by the OR of 48 pads. The LTM synchronizes these signals making use of PDL (Programmable Delay Line) chips and handles the 48 signals with a logic, implemented in the Altera Cyclone FPGA (Field Programmable Gate Array). Besides the trigger, each LTM acts also as slow control board for the TOF front end card (FEAC), monitoring the low voltage and the temperature, and supplying the voltage threshold.

In 2004 ES projected and realized a first prototype of a LTM (6 channels), including all the functionality. During the summer 2004 the LTM was connected to two MRPC exposed to the CERN PS-T10 beam. The results showed a good performance of the board both for the trigger and for the slow control part. As an example the trigger obtained using the FPGA logic, showed an efficiency identical to the beam line trigger, based on the coincidence of four scintillators. These results were presented by ES at ALICE Technical Board (Dec 2004) and later at the conference LECC 2005 in Heidelberg.

 The signals coming from the 72 LTMs are sent to the second trigger layer, called CTTM (Cosmic and Topology Trigger Module), connected to the LTMs through 72 cables, 60 m long. This module is a large area VME board, receiving 1728 bits from the TOF and taking the final trigger decision. It is equipped with three piggy-back cards, each mounting an ALTERA Stratix II FPGA.

The firmware implemented in the 72 LTM Cyclone I and in the 3 Stratix II FPGAs of the CTTM boards, has been written personally by ES, using the VHDL language (Very High Speed Integrated Hardware Description Language). Moreover the candidate wrote the CTTM control software, based on DIM and PVSS standards.

   According with the Monte Carlo simulation, the TOF is expected to accumulate during the 10 years of data taking a dose of 1.2 Gy, while in the Pb-Pb interaction it will be crossed by a particle flux of 100 Hz/cm2.  ES performed two irradiation tests at PSI in Zurich in December 2004 and in November 2006, where the 6 PDLs of the LTM prototype were irradiated with 60 MeV protons, with a fluence 3.2x1011 p/cm2. The PDLs absorbed 440 Gy: no Single Event Upset (SEU) was detected, allowing to place an upper limit on the cross section of sSEU/bit < 3.6 x 10-13 cm-2 (90 % C. L.). These results were presented by ES at 9th ICATTP Conference.

 

 

 b) The TOF HV system

  

 

   ES has the responsibility of the design, the construction and the commissioning of the high voltage system of the ALICE TOF detector. He elaborated the sketch for the distribution of the high voltage to the MRPC, selecting the cables, the connectors and the HV distributors. To accomplish both the mechanical and the safety issues, ES developed, in cooperation with the CAEN company, HV single slot modules, supplying ±8 kV, equipped with tripolar connectors. A long R&D allowed the selection of tripolar connectors matching the tripolar cables mechanic features and satisfying the CERN safety rules. ES selected the HV resin (Sylgard 176), and the heat shrinkable tubes and their mounting steps, required to compensate the mechanical rigidity of the tripolar cable used (Kerpen SY-3x AWG26). The candidate designed the HV distributor box: the HV is supplied by a tripolar connector and is distributed to five unipolar connectors, giving the HV to each MRPC supermodule, through 48 cables. These distributors, placed in the neighbourhood of the VME crate, must have a high reliability while following strictly the safety rules, and maintaining at the same time a small occupancy. High voltage resistors were used, while the distributor was filled with a HV resin. The candidate followed step by step the commissioning of the HV system, making a full test of the 180 tripolar cables, the 180 HV distribution boxes and the 864 unipolar cables.

 

 

c) Study of the gas mixture to optimize the detector performance

 

 

   ES studied the variation of the MRPC performance as a function of the gas mixture used. With respect to the standard mixture (C2F4H2(90 %) + iso-C4H10(5%) + SF6 (5%)), both the relative fraction of the components and the chemical composition were varied. Different types of Freon (i.e. C2F5H) and alternative quenching gas (i.e. CO2) were used. This study showed that the SF6 is a key element of the mixture and cannot be replaced by any gas to get a time resolution as good as 70 ps, while the iso-C4H10 can be eliminated by the gas mixture without spoiling the MRPC performance, if the fraction of SF6 is increased to 7 %. The results of this study were presented by ES at the Conference RPC2003, and published on Nucl.Instrum.Meth.A532 (2004) 562.

 

 

2) NEUTRINO OSCILLATION PHYSICS AT LNGS

 

The study of neutrino oscillation physics at LNGS included two activities:

a) Study of the atmospheric neutrinos with the MACRO experiment;

b) R&D for detectors at the beam from CERN at LNGS (CNGS).

 

 

a)     Study of atmospheric neutrinos with the MACRO experiment

 

 

The most important contribution of the candidate was an original analysis, concerning the upwardthroughgoing muons, produced by the interaction of a muon neutrino in the rock below MACRO. The neutrino oscillation probability depends on the ratio Ln/En, where Ln is the distance between the creation and the interaction point, while En is the neutrino energy. The measurement of the residual upgoing muon energy is appealing, since Monte Carlo simulations show that a tight correlation exists between the upgoing muon residual energy and the parent neutrino energy. Such measurement, never addressed before by an underground detector, has several experimental difficulties since neutrino underground detectors do not make use of magnetic field.

The candidate idea was to use the multiple scattering experienced by the muons, while crossing the detector, to estimate their energy. Given the complexity of such measurement, a MACRO group was constitued, made of five researchers, led by ES.To reach this goal ES made use of a peculiar MACRO electronics (built to search for slow monopoles) to operate the streamer tube system in drift mode. As a result the space resolution was improved from s =1 cm to s =3 mm. To calibrate the method, ES reproduced a slice of the MACRO detector, equipped with the same electronics, and exposed it to the CERN PS-T9 and SPS – X7 beams. These tests showed a good capability of the method in reconstructing the muon energy. These results where published in Nucl. Instr. Meth. A492(2002) 376. The MACRO upgoing muon data sample where reanalyzed making use of a neural network, whose inputs are several parameters connected to the multiple coulomb scattering, giving in output a variable representing the muon energy, calibrated with the test beam data. The analysis, using the full statistics of the MACRO upgoing muons, allowed to separate the sample in 4 energy intervals and to estimate the ratio Ln/En, where the calibration between En  and Em  was obtained by Monte Carlo. The results show that the deficit and the angular distribution distortion of the upgoing muons measured by MACRO, with respect to the flux and to the angular distribution expected in the no oscillation hypothesis, is energy dependent. The deviation is stronger at low energy, while it disappears by increasing the energy, according with the oscillation hypothesis with parameters Dm2 ~ 10-3 eV2 , sin22q ~1. To quantify the effect, the ratio R between the number of events with reconstructed energy En<30 GeV and the number of events with En>130 GeV was chosen. The results obtained give Rexp = (0.85 ± 0.16(stat)) to be compared with an expected ratio R = (1.5 ± 0.25(sys+theo)) for the no oscillation hypothesis. The probability P that a fluctuation is the explanation of the R measured value is                        P = 7.5x10-3; when R is combined with the angular distribution, this probability is

P = 1.3x10-6( both measuremenst are absolute flux independent). In both cases a good agreement with the oscillation hypothesis with parameters (Dm2 ,sin22q), compatible with those indicated by Superkamiokande, is found. ES was corresponding author of the paper published on Phys. Lett. B566(2003) 35. The analysis was also quoted on the Long Base Line News (August 2002) and was presented by ES at:

- invited talk at  NATO Advanced Workshop Cosmic radiation: from astronomy to

  particle physics, Ojuda (Morocco);

- talk at the Conference EPS HEP2001, Budapest (Hungary);

- talk at the Conference TAUP2001, LNGS (Italy);

- talk at the 39th Erice International School of Subnuclear Physics, Erice (Italy);

- talk at the Conference PANIC02, Osaka (Japan).

 

 

 b) R&D for CNGS (Cern to LNGS neutrino beam) detector

 

 

    In the framework of the R&D for the CNGS detector, from 1995 to 1999 was member of the NOE Collaboration and coordinator of the LNGS-NOE group, made of four researchers. This R&D, supported by INFN, showed the feasibility of the hardware components, required to reach the performance of the Letter of Intent. During the 1998, a prototype of a scintillating fiber calorimeter was built and exposed to an electron and charged pion beam at CERN. The LNGS group, had the responsibility to build the calorimeter electronic boards, the tail-catcher detector made of streamer tubes, to study the hadronic shower containment, and to make the calorimeter signal cables. As far as the software is concerned, ES provided a GEANT3.21 based calorimeter simulation, with emphasis on the study of the energy resolution as a function of the fluctuation of several parameters (photoelectron statistics, gain fluctuation, Birk low parameters, etc). The simulations gave an estimate of the energy resolution s / E = 42%/Ö E(GeV) + 5 %  for charged pions  s / E = 17%/ÖE(GeV) + 1 %  for electrons. The data collected during the test beam fully confirmed the simulation. ES studied the calorimeter photomultiplier performance in the fringe magnetic field. In cooperation with the Hamamatsu company, made tests using several “m-metal” shields, optimizing the geometry and the material choice. As a result a good PMT performance up to 10 mT, was obtained.

   The results of this R&D are documented by six papers published on Nucl. Instr. Meth. A; ES presented the results obtained in NOE TEST at the conferences WIN97, TAU98 and CALOR2000.

 

 

3) COSMIC RAY PHYSICS WITH THE MACRO DETECTOR

 

 

  The candidate gave a contribution both to the hardware and to the software in the muon working group.

Hardware:

• ES participated to the construction and to the commissioning of the MACRO muon tracking system, made of limited streamer tube. He had the responsibility of mounting and commissioning the EST wall of the Supermodules 4, 5 and 6, coordinating the italian team, mounting the streamer tube system, with the USA team, mounting the scintillator system. He run these Supermodules in stand alone mode, analyzed the collected data, and developed the software tools for the data quality control, before including the Supermodules in the standard MACRO DAQ.

• In the period 1995-2000, provided a personal contribution to the experiment management and running. From May 1997 to April 1998 was Run Coordinator .

 

 

Software:

• gave a personal contribution in the study of high energy cosmic ray muons, allowing to get information on primary cosmic rays ERC >1 TeV. The interpretation of the experimental results in terms of cosmic ray composition requires an extensive use of Monte Carlo codes, describing the hadronic interaction of primary cosmic rays, the development of the shower in atmosphere, and the propagation of TeV muons through the rock. In his Ph. D thesis, ES studied the decoherence function, sensitive to the cross section of the primary cosmic rays, to the transverse momentum of the muon parent mesons, and to the multiple scattering suffered by the muons while crossing the rock. The decoherence is weakly sensitive to the Cosmic Ray (CR) chemical composition, allowing a disentangle between the features of the hadronic interaction and the CR chemical composition. ES performed this analysis taking care of the detector simulation using GEANT, putting the emphasis on the evaluation of the systematic effects. The large MACRO dimensions allowed to study the decoherence up to 70 m (corresponding to  < ptp,K  > ³ 1.5 GeV), in several angular and rock depth windows. Data were compared with Monte Carlo simulations based on different hadronic interaction models. The most important result is that only hadronic models in which the meson transverse momentum distribution follows a power law can reproduce the experimental data. The measurement accuracy allowed to find an excess of short distance muon pair, compatible with the process m + N à m + N + m+ + m-.  ES presented these results at six international conferences and was corresponding author of the paper published in Phys. Rev. D60 (1999) 032001.

 The candidate addressed the problem of interfacing the Monte Carlo event generator with the detector simulation, GEANT based. Such interface is straightforward in accelerator experiments, where the interaction point is well known, while on the contrary it's much more tricky in cosmic ray experiments. ES elaborated a new method, decreasing remarkably the CPU time required to generate the muon events, while keeping the same accuracy of the standard technique. This method, published in Astr. Phys., 7 (1997) 101, was used by several cosmic ray experiment, such as LVD and EAS-TOP (see. Phys. 9 (1998) 185).

 

 

OTHER ACTIVITIES

 

• From January 2000 to December 2001 was LNGS link person for the OPERA experiment, having the task, from the LNGS Direction, to speed up the integration of the experiment with the LNGS. ES participated to several OPERA meetings, giving a logistic contribution and supporting the tests the Collaboration was doing at LNGS.

• Responsibility of the construction of a large area ( > 5 m2 ) scintillator based external trigger for the ICARUS 10 m3 prototype, collecting data in the spring 2000 at LNGS. This trigger was designed, constructed and commissioned by ES. It allowed the data taking of the ICARUS prototype, selecting a large statistics of muon tracks. The results are published on Nucl. Instr. Meth. A 498 (2003) 292.

• LNGS seminar organizer in the period 1995 – 2000; member of the Organizing Committee of the International Conference ISVHECRI98, (LNGS, July 12-17 1998).

 

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