BESIII is a multipurpose spectrometer optimized for physics in the tau-charm energy region. Both detector and accelerator are undergoing an upgrade program, that will allow BESIII to run until 2029. A major upgrade is the replacement of the inner drift chamber with a new detector based on Cylindrical Gas Electron Multipliers to improve both the secondary vertex reconstruction and the radiation tolerance. The CGEM-IT will be composed of three coaxial layers of cylindrical triple GEMs, operating in an Ar$\,$+$\,$iC$_4$H$_{10}$ (90:10) gas mixture with field and gain optimized to maximize the spatial resolution. The new detector is readout with innovative TIGER electronics produced in 110$\,$nm CMOS technology. The front end is a custom designed 64$\,$channel ASIC featuring a fully digital output and operated in trigger-less mode. It can provide analog charge and time measurements with a TDC time resolution better than 100$\,$ps, that will allow to operate in $μ$TPC mode. Before the installation inside BESIII, foreseen in 2021, a long standalone data taking is ongoing at the Institute of High Energy Physics in Beijing; currently, the first two cylindrical chambers are available for the test, and are used to complete the integration between the detector and the electronics and to assess the required performance. In this proceeding a description of the CGEM-IT project, the TIGER features and performance, and the results of the analysis of first cosmic ray data taking will be presented. Focus will be given on the strip analysis, from which it is possible to measure the basic properties of the detector, and the cluster analysis. The first preliminary results on efficiency and spatial resolution will be also presented.
The Beijing Spectrometer (BESIII) is an experimental setup located at the Beijing Electron Positron Collider (BEPCII). The recently approved ten-year extension of data acquisition for BESIII prompted an upgrade program for both the BEPCII collider that houses the experiment and some of the sub-detectors that make up the spectrometer. The current inner drift chamber is suffering from aging and it has been proposed to replace it with a detector based on the Cylindrical Gas Electron Multiplier (CGEM) technology. The CGEM Inner Tracker (CGEM-IT) consists of three coaxial layers of triple GEM. The …
We present the design and characterization of TIGER (Turin Integrated Gem Electronics for Readout), a 64-channel ASIC developed for the readout of the CGEM (Cylindrical Gas Electron Multiplier) detector, the proposed inner tracker for the 2018 upgrade of the BESIII experiment, carried out at BEPCII in Beijing. Each ASIC channel features a charge sensitive amplifier coupled to a dual-branch shaper stage, optimized for timing and charge measurement, followed by a mixed-mode back-end that extracts and digitizes the timestamp and charge of the input signals. The time-of-arrival is provided by a se…
This thesis reports the various phases of the life cycle of a cylindrical GEM detector, developed within the context of the CGEM-IT project. This represents the Italian proposal for the upgrade of the BESIII inner tracker, which has been suffering from aging phenomena due to the high luminosity. The construction of the detector at Frascati National Laboratories and the early phases of its commissioning at IHEP are described in detail. In the last two chapters, noise studies on data collected using a CGEM detector with a full readout chain near the BEPC-II interaction point will be presented, s…
A cylindrical GEM tracker is under construction in order to replace and improve the inner tracking system of the BESIII experiment. Tests with planar chamber prototypes were carried out on the H4 beam line of SPS (CERN) with muons of 150 GeV/c momentum, to evaluate the efficiency and resolution under different working conditions. The obtained efficiency was in the 96 - 98% range. Two complementary algorithms for the position determination were developed: the charge centroid and the micro-TPC methods. With the former, resolutions <100 micron and <200 micron were achieved without and with magnet…
A cylindrical GEM detector is under development, to serve as an upgraded inner tracker at the BESIII spectrometer. It will consist of three layers of cylindrically-shaped triple GEMs surrounding the interaction point. The experiment is taking data at the e+e- collider BEPCII in Beijing (China) and the GEM tracker will be installed in 2018. Tests on the performances of triple GEMs in strong magnetic field have been run by means of the muon beam available in the H4 line of SPS (CERN) with both planar chambers and the first cylindrical prototype. Efficiencies and resolutions have been evaluated u…
Gas detector are very light instrument used in high energy physics to measure the particle properties: position and momentum. Through high electric field is possible to use the Gas Electron Multiplier (GEM) technology to detect the particles and to exploit the its properties to construct a large area detector, such as the new IT for BESIII. The state of the art in the GEM production allow to create very large area GEM foils (up to 50x100 cm2) and thanks to the small thickness of these foil is it possible to shape it to the desired form: a Cylindrical Gas Electron Multiplier (CGEM) is then prop…
The Beijing Electron Spectrometer III (BESIII) is a multipurpose detector that collects data provided by the collision in the Beijing Electron Positron Collider II (BEPCII), hosted at the Institute of High Energy Physics of Beijing. Since the beginning of its operation, BESIII has collected the world largest sample of J/ψ and ψ(2s). Due to the increase of the luminosity up to its nominal value of 10^33 cm-2 s-1 and aging effect, the MDC decreases its efficiency in the first layers up to 35% with respect to the value in 2014. Since BESIII has to take data up to 2022 with the chance to continue …
The third generation of the Beijing Electron Spectrometer, BESIII, is an apparatus for high energy physics research. The hunting of new particles and the measurement of their properties or the research of rare processes are sought to understand if the measurements confirm the Standard Model and to look for physics beyond it. The detectors ensure the reconstruction of events belonging to the sub-atomic domain. The operation and the efficiency of the BESIII inner tracker is compromised due to the the radiation level of the apparatus. A new detector is needed to guarantee better performance and t…
The Cylindrical GEM-Inner Tracker (CGEM-IT) is the upgrade of the internal tracking system of the BESIII experiment. It consists of three layers of cylindrically-shaped triple GEMs, with important innovations with respect to the existing GEM detectors, in order to achieve the best performance with the lowest material budget. It will be the first cylindrical GEM running with analog readout inside a 1T magnetic field. The simultaneous measurement of both the deposited charge and the signal time will permit to use a combination of two algorithms to evaluate the spatial position of the charged tra…
Gas Electron Multipliers (GEMs) can be produced in large foils and molded in different shapes. The possibility to create cylindrical layers has opened the opportunity to use such detector as internal tracker at collider experiments. One crucial item is to have low material budget in the active area, so the supporting structure of anode and cathode must be light. KLOE2 collaboration has built the first Cylindrical GEM detector with honeycomb material with carbon fiber skins produced at high temperature. BESIII is developing an innovative CGEM detector with charge and time readout. Among several…
BESIII is a particle physics experiment located at the Institute of High-Energy Physics (BEPC-II) e+e- collider at IHEP in Beijing. The Italian collaboration is leading the effort for the development of a cylindrical GEM (CGEM) detector with analog readout to upgrade the current inner drift chamber that is suffering early ageing due to the increase of the machine luminosity. Within the CGEM project, this work aims to perform full detector simulation for the optimisation of the tracker geometry and its operational parameters. The goal is achieved by means of three different, but well connected,…
Gas detector are very light instrument used in high energy physics to measure the particle properties: position and momentum. Through high electric field is possible to use the Gas Electron Multiplier (GEM) technology to detect the charged particles and to exploit their properties to construct a large area detector, such as the new IT for BESIII. The state of the art in the GEM production allows to create very large area GEM foils (up to 50x100 $\mathrm{cm}^2$) and thanks to the small thickness of these foils is it possible to shape it to the desired form: a Cylindrical Gas Electron Multiplier…
In the framework of detector development, Monte Carlo simulations play a key role in the evaluation of the expected performance and the full understanding of the behavior in beam conditions. In particular, a software which simulates the response of the detector to the particle passage is mandatory to test different setups and solutions, such as geometries, fields, voltages etc. and to understand the test beam data. For gas trackers, existing softwares, such as GARFIELD, perform a very detailed simulation of the physical processes but are also CPU time consuming. For the new cylindrical GEM tra…
The extension of data acquisition for the BEijing Spectrometer (BESIII) experiment until at least 2030 has resulted in upgrades to both the accelerator and the detector. An innovative Cylindrical Gas Electron Multiplier (CGEM) is under construction to upgrade the inner tracker, which is suffering from aging. The CGEM Inner Tracker (CGEM -IT) was designed to restore efficiency and enhance the reconstruction of the secondary vertexes position. Reconstruction in the magnetic field of 1 T requires an analog readout and an electronic contribution to the time resolution better than 5 ns. The entire …
An innovative Cylindrical Gas Electron Multiplier (CGEM) detector is under construction for the upgrade of the inner tracker of the BESIII experiment. A novel system has been worked out for the readout of the CGEM detector, including a new ASIC, dubbed TIGER -Torino Integrated GEM Electronics for Readout, designed for the amplification and digitization of the CGEM output signals. The data output by TIGER are collected and processed by a first FPGA-based module, GEM Read Out Card, in charge of configuration and control of the front-end ASICs. A second FPGA-based module, named GEM Data Concentra…
This paper will discuss the design and construction of BESIII, which is designed to study physics in the tau-charm energy region utilizing the new high luminosity BEPCII double ring e+e- collider. The expected performance will be given based on Monte Carlo simulations and results of cosmic ray and beam tests. In BESIII, tracking and momentum measurements for charged particles are made by a cylindrical multilayer drift chamber in a 1 T superconducting solenoid. Charged particles are identified with a time-of-flight system based on plastic scintillators in conjunction with dE/dx (energy loss per…
For the upgrade of the inner tracker of the BESIII spectrometer, planned for 2018, a lightweight tracker based on an innovative Cylindrical Gas Electron Multiplier (CGEM) detector is now under development. The analogue readout of the CGEM enables the use of a charge centroid algorithm to improve the spatial resolution to better than 130 um while loosening the pitch strip to 650 um, which allows to reduce the total number of channels to about 10 000. The channels are readout by 160 dedicated integrated 64-channel front-end ASICs, providing a time and charge measurement and featuring a fully-dig…
The status of the R&D on the Cylindrical-GEM (CGEM) detector foreseen as Inner Tracker for KLOE-2, the upgrade of the KLOE experiment at the DAFNE phi-factory, will be presented. The R&D includes several activities: i) the construction and complete characterization of the full-size CGEM prototype, equipped with 650 microns pitch 1-D longitudinal strips; ii) the study of the 2-D readout with XV patterned strips and operation in magnetic field (up to 1.5T), performed with small planar prototypes in a dedicated test at the H4-SPS beam facility; iii) the characterization of the single-mask GEM tec…
The reconstruction of charged particle trajectories in tracking detectors is a key problem in the analysis of experimental data for high-energy and nuclear physics. The amount of data in modern experiments is so large that classical tracking methods, such as the Kalman filter, cannot process them fast enough. To solve this problem, we developed two neural network algorithms based on deep learning architectures for track recognition in pixel and strip-based particle detectors. These are TrackNETv3 for local (track by track) and RDGraphNet for global (all tracks in an event) tracking. These algo…
A recently approved ten-year extension of the BESIII experiment (IHEP, Beijing) motivated an upgrade program for both the accelerator and the detector. In particular, the current inner drift chamber is suffering from aging and the proposal is to replace it with a detector based on the cylindrical GEM technology. The CGEM inner tracker (CGEM-IT) consists of three coaxial layers of triple GEM. The tracker is expected to restore efficiency, improve z-determination and secondary vertex position reconstruction with a spatial resolution of 130 μ m in the xy-plane and better than 300 μ m along the be…
