Part of the upgrade of the KLOE detector at the DAΦNE Φ-factory consists of the insertion of a tracking device around the interaction region, composed of four tracking layers with radii from 130 mm to 205 mm and an active length of 700 mm. Each layer was realized as a cylindrical triple-GEM (CGEM) kapton-based detector, a solution that allows us to keep the total material budget below 2% of X0, of utmost importance to limit the multiple scattering of low-momentum tracks at KLOE-2, and to minimize dead spaces. The peculiar readout pattern with XV strips provides a spatial resolution of about 200 μm on both views, while a dedicated readout system has been developed by the KLOE-2 collaboration. It is composed of a digital readout front-end card based on the GASTONE ASIC and a General Interface Board with a configurable FPGA architecture and Gigabit Ethernet. The construction of the four CGEM layers has been completed and the detectors have been tested with a beta source and cosmic-ray muons. The insertion inside the KLOE apparatus was performed in July 2013. The construction procedure and the results of the validation tests will be reported.

The cylindrical GEM detector for the KLOE-2 Inner Tracker

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 Concentrator, builds the trigger selected event packets containing the data and stores them via the main BESIII data acquisition system. The design of the electronics chain, including the power and signal distribution, will be presented together with its performance.

The CGEM-IT readout chain

The BESIII experiment has been collecting data since 2009 at the e+e− collider BEPCII in Beijing, a charm-τ factory characterized by high statistics and high precision. The discovery of exotic charmonium-like states and the still open questions in low-energy QCD led to an extension of the experimental program, with several upgrades. This review focuses on the CGEM-IT, the innovative solution proposed to replace the current inner tracker, which is aging. It consists of three, co-axial, cylindrical triple-GEM detectors and will be the first cylindrical GEM operating inside a 1 T magnetic field with analogue readout. For this purpose, a dedicated mixed-signal ASIC for the readout of CGEM-IT signals and FPGA-based electronics for data processing have been developed. The simultaneous measurement of both ionization charge and time distribution enables three reconstruction algorithms, to cope with the asymmetry of the electron avalanche in the magnetic field and with non-orthogonal incident tracks. The CGEM-IT will not only restore the design efficiency but also improve the secondary vertex reconstruction and the radiation tolerance. The gas mixture and gain settings were chosen to optimize the position resolution to ∼130 µm in the transverse plane and better than 350 µm along the beam direction. This paper addresses the innovative aspects in terms of construction, readout, and software, employed to achieve the design goals as well as the experimental measurements performed during the development and commissioning of the CGEM-IT.

https://www.mdpi.com/2073-8994/14/5/905/pdf?version=1651203161

The CGEM-IT: An Upgrade for the BESIII Experiment

The KLOE-2 experiment started its data taking campaign in November 2014 with an upgraded tracking system at the DAΦNE electron-positron collider at the Frascati National Laboratory of INFN. The new tracking device, the Inner Tracker, operated together with the KLOE-2 Drift Chamber, has been installed to improve track and vertex reconstruction capabilities of the experimental apparatus. The Inner Tracker is a cylindrical GEM detector composed of four cylindrical triple-GEM detectors, each provided with an X-V strips-pads stereo readout. Although GEM detectors are already used in high energy physics experiments, this device is considered a frontier detector due to its fully-cylindrical geometry: KLOE-2 is the first experiment benefiting of this novel detector technology. Alignment and calibration of this detector will be presented together with its operating performance and reconstruction capabilities.

The cylindrical GEM detector of the KLOE-2 experiment

A new front-end data acquisition (DAQ) system has been conceived for the data collection of the new detectors which will be installed by the KLOE2 collaboration. This system consists of a general purpose FPGA based DAQ module and a VME board hosting up to 16 optical links. The DAQ module has been built around a Virtex-4 FPGA and it is able to acquire up to 1024 different channels distributed over 16 front-end slave cards. Each module is a general interface board (GIB) which performs also first level data concentration tasks. The GIB has an optical interface, a RS-232, an USB and a Gigabit Ethernet Interface. The optical interface will be used for DAQ purposes while the Gigabit Ethernet interface for monitoring tasks and debug. Two new detectors exploit this strategy to collect data. Optical links are used to deliver data to the VME board which performs data concentration tasks. The return optical link from the board to the GIB is used to initialize the front-end cards. The VME interface of the module implements the VME 2eSST protocol in order to sustain a peak data rate of up to 320 MB/s. At the moment the system is working at the Frascati National Laboratory (LNF).

http://iopscience.iop.org/article/10.1088/1748-0221/8/04/T04004/pdf

Front-end DAQ strategy and implementation for the KLOE-2 experiment

The KLOE2 experiment has been approved Its data taking is going to start early next year In order to pursue its physics program the KLOE2 collaboration has built two new detectors: the Inner Tracker (IT) and the QCALT Their inclusion in the experiment has triggered the need to upgrade the data acquisition system (daq), initially conceived for the KLOE experiment In this paper we describe the main characteristics of the new data acquisition system

A. D'Uffizi

Papers

Front-end DAQ strategy and implementation for the KLOE-2 experiment

A mew DAQ system strategy and its implementation for the KLOE-2 experiment