UniTO - PROPOSAL PhD programme in_physics HR-MPGD-4-NG-HEP

Transcription

1 UniTO - PROPOSAL PhD programme in_physics HR-MPGD-4-NG-HEP Scientific Project Proposal The PhD Doctoral School in Physics of the University of Turin can host a three-year doctoral programme aimed to develop and optimize an Hybrid Readout of Micro-Pattern Gas Detectors (MPGD) for Next Generation High Energy Physics (HR-MPGD-4-NG-HEP). The BESIIICGEM project, funded by the European Commission, is building within the BESIII Collaboration a new Inner Tracker (CGEM-IT) [1-2] to be installed in 2018 in the BESIII Spectrometer [3]. The new CGEM-IT will benefit of Cylindrical-GEM technology and of a full custom ASIC designed in order to allow its Front End Electronics to implement an innovative analogue hybrid readout, exploiting to reconstruct hits' clusters the usual centroid approach but also the time information in a micro-tpc like approach [4]. The first primary goal of the proposed programme is the implementation and optimization of such an innovative hybrid readout during the test beams expected in 2018 first, and later once the Inner Tracker will have been installed, during data acquisition of the upgraded BESIII Spectrometer. The expected performances of the hybrid readout of the CGEM-IT coupled with the expected upgrade [5] of the BEPCII, the accelerator hosting the BESIII Spectrometer in Beijing, will allow for a new phase in the BESIII Λ c programme [5], to which the candidate is expected to contribute. A next generation accelerator, CEPC, has been recently proposed in P.R.C. [6]. The tremendous challenges introduced by such an experimental scenario can exploit the innovation of the hybrid readout described above. In particular the hybrid readout of MPGD's could be implemented for a new generation of muon detectors, and for the hybrid modules proposed [7] for the TPC of the CEPC detector. This, the technological transfer to the CEPC scenario of the hybrid readout developed for BESIII, represents the second main goal of the prosed doctoral programme. The candidate will be part of the BESIIICGEM Consortium, composed of researchers from Italy, Germany and Sweden, cooperating with IHEP. When involved in the CEPC related activities, he/she will interact with the Center for Excellence in Particle Physics as well (where the Center includes: Tshinghua University, Beijing University, University of Science and Technology, Nankai University, Shangdong University, Xiangtan University, Shanghai Jiaotong University). These research activities received significant funding from the European Commission and INFN. [1] A. Amoroso et al., doi: /j.nima [2] A. Amoroso et al., NCC 39 (2016) 261 [3] M. Ablikim et al., BESIII Collaboration, NIMA 598 (2009) 7 [4] R. Farinelli, MPGD 2016, 13_RD51_aveiro.pdf [5] H. Peng, 2016 JAEA/ASRC Reimei Workshop, Peng.pdf [6] M. Ahmad et al., IHEP-CEPC-DR , via Bogino Torino (Italy) tel fax phdprogrammes@unito.it Page 1/6

2 [7] Y. Gao, IAS HEP 2016, 2(a) State-of-the-art and objectives Gas detectors revolutionised the detection of charged particles, first in nuclear and sub-nuclear experimental Physics, later allowing HEP experiments to exploit high space and time resolution over large instrumented surfaces and volumes, yet with very low material budget, moderate sensitivity to magnetic fields and cost-effectiveness. Latest generations of Micro-Pattern Gas Detectors (MPGDs), exploiting photolithographic technology on flexible and standard PCB supports, such as GEM [1], THGEM [2] and Micromegas (MMs) [3], exhibit good spatial and time resolutions, high rate capability, large sensitive area, flexible geometry, good operational stability and radiation hardness. Planar MPGDs have boosted detection performances in vastly different experimental scenarios: COMPASS, LHCb, TOTEM among the others. Recently Cylindrical-GEM (CGEM) detectors have been or are being developed as Inner Trackers of KLOE2 and BESIII [4]. A further evolution lead to the ATLAS New-Small-Wheel (NSW) [5] and the CMS GE1/1 [6] upgrades with large area MMs and GEMs respectively, thanks also to the MPGD oriented worldwide RD51 Technological Collaboration. Avalanches in MPGDs produce signals readout by induction onto an anode plane segmented in strips or pads; the readout may be digital or analogue. The latter, coupled with the default charge centroid clusterization approach, provides the best spatial resolution for a position obtained as the mean of the strip positions weighted by the charge collected on the strips. A resolution of microns, depending on the chamber geometry, gas diffusion and operating parameters, can be achieved for tracks perpendicular to the MPGD and with no or low magnetic field. The resolution significantly worsen for larger tracks' incident angles or intense magnetic fields, the avalanche distribution being no more optimal (not gaussian) for the charge centroid method. A new readout approach developed by ATLAS for MMs allows, combined with the charge centroid, for stable performance both as function of the incident track angle and of the magnetic field [7]. As in a Time Projection Chamber, the new micro-tpc readout technique exploits time information to evaluate the coordinate perpendicular to readout plane for each fired strip. Measuring the drift time of electrons produced in the drift region by ionization processes, and knowing the drift velocity, a local track segment can be reconstructed within each detector, significantly improving the spatial resolution. Before BESIII such a technique have been applied only to MMs and to GEM detectors not in a sizeable magnetic field. Such a goal can be achieved exploiting dedicated ASICs for GEM detectors, a significant step forward w.r.t. the first era in which MPGDs are usually readout by using the same front-end electronics (FEE) employed for silicon strip sensors (e.g. the APV chip, originally developed for the CMS silicon tracker). Depending on the application, different types of architectures have been used, from pure binary to more sophisticated ASIC embedding on board also the analog to digital conversion. The Turin group of the BESIIICGEM Consortium have designed and developed an ASIC dedicated to the readout of the new Inner Tracker of the BESIII Collaboration. The BESIII Collaboration plans to upgrade its Inner Tracker with a Cylindrical-GEM Inner Tracker. (CGEM-IT) [8-9] The CGEM-IT will be readout by an innovative hybrid readout, combining the information from the classic centroid approach but also exploiting the time information as if the via Bogino Torino (Italy) tel fax phdprogrammes@unito.it Page 2/6

3 CGEM chambers themselves were micro TPCs (micro-tpc readout) [10]. The CGEM-IT with its hybrid readout is a completely beyond the state of the art detector, leading the way for future MPGD-based applications. The candidate is expected to join the development and optimisation of hybrid readout algorithms, to be implemented first, within the BESIII Collaboration, on the readout of its CGEM-IT, and later, within the Circular Electron Positron Collider (CEPC) joint effort [11], for the feasibility studies involving next generation MPGDs. [1] F.Sauli, NIMA 386 (1997) 531 [2] L.Periale et al., NIMA 478 (2002) 377 [3] I.Giomataris et al., NIMA 376 (1996) 29 [4] A. Amoroso et al., NIMA 824 (2016) 515 [5] J. Manjarres et al., JINST 7 (2012) C03040 [6] CERN-LHCC CMS-TDR-013 (2015) [7] M. Trovatelli, Il Nuovo Cimento 37C (2014) 1 [8] D. Bettoni et al., PoS 292 (TIPP2014) [9] A. Amoroso et al., NCC 39 (2016) 261 [10] R. Farinelli, MPGD 2016, 13_RD51_aveiro.pdf [11] M. Ahmad et al., IHEP-CEPC-DR , 2(b) Methodology, work plan, team organisation The proposed programme aims to two main goals: - a first one related to the BESIII experimental scenario; - a second one related to the Circular Electron Positron Collider (CEPC) experimental scenario. The first main goal of the programme is leading to a mature and optimized stage the dedicated SW algorithms for space performance optimization in the readout of large GEM and CGEM detectors exposed to sizeable magnetic fields. Such task is currently being performed within the BESIIICGEM project, an H2020 project funded within the call H2020-MSCARISE-2014, whose Coordinator, Prof. Marco Maggiora, is the proponent of the current proposal. The project aims to the installation of a new CGEM Inner Tracker (CGEM-IT) in the BESIII Spectrometer, currently settled on the BEPCII at IHEP, Beijing [1-2]. In more details, one of the two main goals of the programme is providing a stable space resolution in the range um, for non orthogonal tracks and/or in presence of a high magnetic field (up to 1T), by combining charge-centroid and TPC mode on a hybrid readout [3]. GEM technology is well understood, the know-how available to perform extensive R&D. Data from cosmic runs and from tests with muon beams in a magnetic field up to 1T can be analysed in the SW framework developed for the data analysis of the BESIII GEM prototypes: a very versatile and powerful reconstruction suite easily adaptable to different detector configuration, readout electronics and experimental setups, for online and offline use. Online version allows for the monitoring of detector performance during tests; offline release exploits charge centroid method to via Bogino Torino (Italy) tel fax phdprogrammes@unito.it Page 3/6

4 reconstruct detector clusters and can be used for a fine data analysis. Such SW has been extensively tested and used to analyse BESIII GEM prototype data achieving the unprecedented space resolution of ~190um in a 1T magnetic field [4]. A feasibility study confirmed the capability of GEM detectors to reconstruct clusters in TPC mode, allowed by a 12ns time resolution. Within this framework, GARFIELD simulations can feed to micro-tpc algorithms the drift velocity that, combined with the time information, allows a 2D reconstruction of the hits, once a Hough transform algorithm has cleanup spurious hits and the capacitive coupling between adjacent strips has been accounted for. The new hybrid readout can be and has been then tested on the CGEM-IT in test beams and with cosmic rays, but the real challenge will be the optimization and calibration of the hybrid readout once the CGEM-IT will be fully part of the BESIII Spectrometer in the late The effects of including the CGEM-IT in the BESIII Simulation and Reconstruction code is and will be explored by the mean of MonteCarlo simulations, considering as benchmark channels Bhabha events or final states with long living particles and hence displaced secondary vertices. In the proposed PhD programme the candidate will first join the large group focused within the BESIIICGEM Project on these tasks. The group includes PhD students, junior and senior researchers from Italy (Universities of Turin and Ferrara and INFN Sections of Turin, Ferrara and Frascati), from Germany (Mainz University and HIM) and from P.R.C. (IHEP). Since in the first PhD year the University of Turin Doctoral Programme in Physics foresees several exams to be faced, for the first year the candidate will be able to devote no more that 50% of his time to field research. It will hence take him/her the first year of the Doctoral Programme to get acquainted with the progresses performed within the BESIIICGEM project and be ready to provide a personal contribution. In the first year he/she will hence cooperate in the effort of reaching a full readiness of the above described algorithms for the commissioning of the CGEM-IT once installed at the end of In the second year of doctoral programme, in principle free from exams, the candidate is expected to contribute independently to the calibration and optimisation of the hybrid readout, making use of the benchmark channels described above and focusing on an analysis agreed with the Collaboration exploiting the significant improvements introduced by the CGEM-IT with the hybrid readout in the detection and reconstruction of complex events involving secondary vertices. In particular BESIII is nowadays performing an extensive investigation [5] of the Λ c production and properties. An upgrade of the BEPCII is expected [5] to provide, within the temporal scope of this doctoral programme, an unprecedented statistic of Λ c 's produced at threshold. The combination of the BEPCII upgrade and the availability of a much better resolution in the reconstruction of secondary vertices expected to be introduced by the CGEM-IT, will allow for and at the same time will require to perform again the analyses BESIII is currently showing in the international conferences (and that will be soon published) exploiting the larger available statistics. It will be possible to investigate the Λ c form factors at threshold as well, with a statistics large enough to hopefully shed light on the internal Λ c structure and properties. The involvement of the analysis that will be assigned to the candidate within the framework described above will gradually take over the efforts on the micro-tpc algorithms optimization for the CGEM-IT, continuing in the third year of the doctoral programme and being hopefully completed, leading to the corresponding publication, within the end of the third year. via Bogino Torino (Italy) tel fax phdprogrammes@unito.it Page 4/6

5 The second main goal of the doctoral programme must be contextualised within the CEPC experimental scenario [6]. MPGDs, due to their excellent spatial and time resolution, high rate capability and scalability to large size detectors, are excellent candidates for muon detection systems of future experiments at forthcoming particle accelerators. In particular CEPC may be an experimental scenario at energy and intensity frontiers requiring very large area muon detection systems of unprecedented complexity and precision. The feasibility of using MPGD detectors exploiting an hybrid readout to realize such muon detection systems can be investigated making use of MonteCarlo simulations. The candidate will join in this effort a large group that is building up nowadays in Italy, involving detector and simulation experts from many different INFN sites. Such a team aims to explore the possibility to adopt innovative detectors in the next generation large accelerators. This will constitute the second goal of the doctoral program for the candidate. Several researchers from the team participated in Sep to the CEPC-SppC Study Group Meeting held in the Beihang University, Beijing. Exploiting the knowledge and experience the candidate will have built up in the first two years of his/her doctoral programme, he/she is expected to contribute to these feasibility studies the innovation introduced by the hybrid readout. The candidate will also interact with the already existing groups in P.R.C. that plans to instrument the main tracker of the CEPC detector, a TPC, with hybrid MPGD detector modules formed of both GEM and MMs detectors [8]. Such modules would be the ideal application for the hybrid readout techniques developed for the CGEM-IT. The candidate and the INFN groups can offer to the groups developing the hybrid modules for the CPEC detector in P.R.C., the know-how and the experience needed to integrate in the project an hybrid readout exploiting the time information as well for the hits' cluster reconstruction. Such tasks related to the CPEC experimental scenario will be performed in parallel with the BESIII related physical analysis described above during the third year of the doctoral programme. CEPC is a huge project, involving dozens of Universities and Institutions within P.R.C. While the Italian BESIIICGEM groups within INFN experience already since 2009 a long lasting and fruitful collaboration with IHEP, the candidate will probably come and will certainly cooperate, besides IHEP, with the Center for Excellence in Particle Physics, that includes these Universities: Tshinghua University, Beijing University, University of Science and Technology, Nankai University, Shangdong University, Xiangtan University, Shanghai Jiaotong University. The candidate, while attending his/her doctoral programme, will be associated to the INFN Section of Turin. Being an INFN Scientific Associate means to access the specific funding INFN is providing both for the BESIII and the detector R&D's related sets of tasks. The BESIIICGEM project is funded by the European Commission within the H2020-MSCARISE call with 1.5M in the years INFN funds the BESIII and BESIIICGEM activities with around 3M in the years INFN will fund the R&D activities on detectors for next generation accelerators starting from Jan [1] M. Ablikim et al., BESIII Collaboration, NIMA 598 (2009) 7 via Bogino Torino (Italy) tel fax phdprogrammes@unito.it Page 5/6

6 [2] NIMA 614 (2010) 345 [3] R. Farinelli, MPGD 2016, 13_RD51_aveiro.pdf [4] G. Cibinetto et al., MPGD 2015, [5] H. Peng, 2016 JAEA/ASRC Reimei Workshop, Peng.pdf [6] M. Ahmad et al., IHEP-CEPC-DR , [7] [8] Y. Gao, IAS HEP 2016, Contact: Prof. Marco MAGGIORA Department of Physics, University of Turin and INFN, Turin Via P. Giuria Turin ITALY marco.maggiora@unito.it via Bogino Torino (Italy) tel fax phdprogrammes@unito.it Page 6/6