We report on the characterization of pad Front End Board (pFEB) for small-strip Thin Gap Chamber (sTGC) prototype. The pFEB is based on Field Programmable Gate Array (FPGA) and Application-Specific Integrated Circuit (ASIC). It has been built to verify the capabilities of the sTGC detector for the ATLAS Phase-I New Small Wheel (NSW) upgrade. The pFEB consists of three VMM2 front-end chips, two Kintex-7 FPGAs used to buffer the VMM2 data, a Gigabit Ethernet Transceiver (GET) and all the required connectors. The VMM2, designed at BNL, is composed of 64 linear front-end channels. Each channel integrates a Charge Sensitive Amplifier (CSA), a shaper, a stable band-gap referenced baseline, several ADCs and other functions. The GET works at physical layer of the network. The mini-SAS connector accepts three external signals (40MHz clock, reset and trigger), which are used for synchronization of several pFEBs. Additionally, the pFEB can work in the case of self trigger mode and external trigger mode. The specific characteristics and implementations are described in detail. Also, the performance of this new type of sTGC detector has been studied with cosmic ray muons.

A front-end electronics prototype for the ATLAS small-strip Thin Gap Chamber (sTGC) based on gigabit Ethernet has been developed. The prototype is designed to read out signals of pads, wires, and strips of the sTGC detector. The prototype includes two VMM2 chips developed to read out the signals of the sTGC, a Xilinx Kintex-7 field-programmable gate array (FPGA) used for the VMM2 configuration and the events storage, and a gigabit Ethernet transceiver PHY chip for interfacing with a computer. The VMM2 chip is designed for the readout of the Micromegas detector and sTGC detector, which is composed of 64 linear front-end channels. Each channel integrates a charge-sensitive amplifier, a shaper, several analog-to-digital converters, and other digital functions. For a bunch-crossing interval of 25 ns, events are continuously read out by the FPGA and forwarded to the computer. The interface between the computer and the prototype has been measured to reach an error-free rate of 900 Mb/s, therefore making a very effective use of the available bandwidth. Additionally, the computer can control several prototypes of this kind simultaneously via the Ethernet interface. At present, the prototype will be used for the sTGC performance test. The features of the prototype are described in detail.

This concept of test platform is based on the test requirements of the front-end board (FEB) which is developed for the phase I upgrade of the small Thin Gap Chamber(sTGC) detector on New Small Wheel(NSW) of ATLAS. The front-end electronics system of sTGC consists of 1,536 FEBs with about 322,000 readout of strips, wires and pads in total. A test platform for FEB with up to 256 channels has been designed to keep the testing efficiency at a controllable level. We present the circuit model architecture of the platform, and its functions and implementation as well. The firmware based on Field Programmable Gate Array (FPGA) and the software based on PC have been developed, and basic test methods have been established. FEB readout measurements have been performed in analog injection from the test platform, which will provide a fast and efficient test method for the production of FEB.

Ammonia (NH₃) is the most abundant alkaline gas in the atmosphere and the cause of the majority of secondary particles in particulate matter PM2.5. The method of ultraviolet spectrum analysis is generally adopted in traditional ammonia concentration detection with a deuterium or xenon lamp, and its cost is relatively high. In this paper, white light-emitting diodes of a lower cost are used as an alternative light source. Then experimental research on ammonia concentration detection is carried out, and the results are compared with those using white light-emitting diodes, deuterium, and xenon lamps. The results show that, under the same experimental conditions, using white light-emitting diodes to measure the ammonia concentration can achieve the same accuracy as using deuterium or xenon lamps. This conclusion provides a solution for light source selection for ammonia concentration detection with low cost and guaranteed accuracy.

Ammonia(NH₃) is the most abundant alkaline gas in the atmosphere. It is the root cause of the formation of most secondary particulates in PM2.5 and the accelerator of the haze pollution formation in the atmosphere. Therefore the monitoring of the NH₃ concentration is very important to the environmental protection. In this paper, the principle of NH₃ concentration detection based on Lambert-Beer law has been introduced. A dual-channel modulated ultraviolet photoelectric signal detection circuit for NH₃ concentration has been designed and its performance index has been studied. And then a precision detection circuit is designed, which is composed of a trans-impedance amplifier and a lock-in amplifier, with which the output of the UV photoelectric detector can be amplified to a suitable voltage range, and the DC noise of the pre-stage amplifier is effectively removed by the lock-in amplifier. The designed circuit has been tested for the NH3 concentration quantitative measuring in the laboratory, with the exchange calibration method being used to ensure the consistency of the two channels. It can be drawn from the test results that the designed circuit is of high SNR, measuring accuracy and a large dynamic range. The NH₃ concentration detection limit of vehicle emissions can reach 2ppm, while the detection precision is ±19ppm.

Through analyzing the current situation and existing problems of practical teaching of photoelectric countermeasure equipment, in order to improve the ability of trainees to take up their posts, satisfy the needs of military colleges teaching mode in the new era, we carried out research on the reform of practical teaching of optoelectronic countermeasure equipment, Optimized the integrated teaching content combining theory, experiment and project, and explored the comprehensive application mode of various teaching, scientific research and equipment platforms, It has formed a practical teaching system that meets the requirements of “being able to use, support, test and repair”, It is abbreviated as “four skills”, Practice has proved that it has achieved a good teaching results.