The Research On Scalable Readout System For Micro-Pattern Gas Detectors

In recent two decades, with the rapid development of the electronic technology, Micro Pattern Gas Detectors (MPGDs), which are typically represented by Micromegas and Gas Electron Multiplier (GEM), have been fully developed. For the advantages of their excellent time and spatial resolutions, high radiation resistance, high rate capability, high gain capability and large active areas, they have been widely studied and applied in the fields of high energy physics (HEP) experiments, astrophysics, nuclear medical imaging, industrial detection and safety monitoring etc. The broad and different application prospects of MPGDs, have put forward different performance requirements to the corresponding readout electronics (such as channel number scale, counting rate, radiation resistance, different measurement precision, etc.). Based on the diversities of these requirements and the limitations of the discrete-component-based front-end electronics, a number of different front-end ASIC chips for MPGDs have been developed at home and abroad, and the corresponding electronics readout systems are designed.At present, in field of MPGDs, the development of gas detectors walks in front of the related electronics. The development of related electronics lags behind, which has become the bottleneck restricting the study and application of MPGDs. International R & D the electronics for MPGDs as well as the MPGD detectors, a variety of readout ASIC chips have been developed to detect different target experiments, such as APV25, VA series, AGET, VFAT2, GASTONE, MICROROC, etc. The Scalable Readout System (SRS) and the Multi-Purpose Digitizer readout system (MPD) are already developed for the purpose of adapting to different detection targets and gas detector experiments scales. China follows the international pace, has the ability to develop the high performance MPGDs, but the development of related electronics lags behind the international level. Tsinghua University, the Chinese Academy of Sciences, Institute of high energy physics and other domestic counterparts who have the ability to develop the ASIC studies, designed the ASIC readout chips, such as CASAGEM, GEMROC, and GEMPROC etc. Studying and designing the scalable readout system, which can be compatible with vigorous development of ASIC chips at home and abroad, adapt to different detector targets and different experiment scales, is an urgent problem need to be solved by the related domestic fields.Considering the prosperous application whereas the lack of study in china of the scalable and general-purpose readout electronic system used for the MPGD detectors, this dissertation studies kinds of typical electronic readout systems of gas detectors both at home and abroad, including the discrete-component-based electronic readout system of MDC (Main Drift Chamber) of BESIII, the front-end-ASIC-based MPD electronic readout system, the SRS produced by CERN and the ATCA-SRS which is the industrial scalable electronic readout system. Referencing the idea of scalable readout system raised by the RD51 Collaboration and many other general-purpose readout electronic system designs, this dissertation introduces the Scalable Readout System for MPGD detectors, which can not only be compatible with kinds of potential ASIC chips to be used in different gas detectors but also adapt to different scale to meet the needs of different experiments. The VA 140, AGET and APV25 are discussed in this dissertation to prove the compatibility and scalability of the prototype SRS system.The prototype SRS system consists of Data Acquisition Cells (DAQ Cells), and each DAQ Cell includes three kinds of modules, the Front-End ASIC Card which is the carrier of multi-channel charge measurement ASIC chips, the Adapter Card which digitizes the analog signals from Front-End ASIC Card and sends the data to the Front-End Card (FEC) using PCIe connectors and the Front-End Card which processes the data further using FPGA (Field Programmable Gate Array) on it and communicates with PC. By configuring the PCIe connectors, the FEC is able to be compatible with different Front-End ASIC Cards based on different ASIC chips and the corresponding Adapter Card, which can meet the demands of different experiments and expand the application prospects of the prototype SRS system. By using the Ethernet interface on FEC, the DAQ Cell can form different topology structures, which allows users to change the number of the DAQ Cells to meet the needs of different MPGD detectors. The VA140-SRS based on VA140 chip and the AGET-SRS based on AGET chip, which have the electronic noise (RMS) about 0.15 fC and better than 0.3 fC respectively, both integral linearities better than 1.5%, enjoy good performances and satisfy the needs of MPGD detectors. The Eurocard standard crates and the AC/DC power modules used in the prototype enable it possible to handle 17 DAQ Cells per crate, corresponding to 8704 VA140 channels and 4652 AGET channels respectively.The prototype SRS system can be used not only in the MPGD detectors, but also in many other fields of multi-channel detectors such as Silicon Micro-strip detectors. Besides, by transplanting the SRS system to ATCA crates and industrializing the SRS system, the performance of the system can be improved further and larger scale application can be achieved.