The large number of electronics channels has become an issue to the further applications of micropattern gas detectors (MPGDs) and poses a big challenge for the integration, power consumption, cooling, and cost. Induced position encoding readout technique provides an attractive way to significantly reduce the number of readout channels. In this paper, we present an extensible induced position encoding readout method for MPGDs. The method is demonstrated by the Eulerian path of the graph theory. A standard encoding rule is provided, and a general formula of encoding and decoding for n channels is derived. Under the premise of such method, a 1-D induced position encoding readout prototyping board is designed on a 5 × 5 cm 2 thick gas electron multiplier, where 47 anode strips are readout by 15 encoded multiplexing channels. Verification tests are carried out on an 8-keV Cu X-ray source with 100-μm slit. The test results show a robust feasibility of the method and have a good spatial resolution and linearity in its position response. This method can dramatically reduce the number of readout channels, has potential to build large-area detectors, and can be easily adapted to other detectors like MPGDs.

The particle and astrophysical xenon experiment III (PandaX-III) is aimed to search for the Neutrinoless Double Beta Decay (NLDBD) using 200-kg radio-pure high-pressure gaseous xenon time projection chamber (TPC) with Micromegas detectors at both ends. A small-scale prototype TPC equipped with seven Microbulk Micromegas modules has been developed. Each Micromegas module has 128 anode strip signals to be processed. Highly integrated front-end electronics composed of four frontend cards (FECs) with 1024 channels are designed to read out the charge of Micromegas anode signals digitize the waveform after shaping and send compressed data to the data collection module (DCM). The cornerstone of the front-end electronics is a 64-channel application-specific integrated circuit (ASIC) named AGET, which is based on switched capacitor arrays (SCAs). According to the test results, the integral nonlinearity (INL) of the front-end electronics is less than 1%, and the noise of each readout channel with the input floating is less than 0.9 fC on the condition of 1-μs peaking time and 1-pC dynamic range. Joint tests of front-end electronics with the prototype TPC were carried out using the radioactive sources 137 Cs and 241 Am. The hit map of the Micromegas modules and the energy spectrum have been reconstructed successfully, and the results are satisfying.

The DAMPE (DArk Matter Particle Explorer) is a scientific satellite being developed in China, aimed at cosmic ray study, gamma ray astronomy, and searching for the clue of dark matter particles in the near future. The BGO (Bismuth Germanate Oxide) Calorimeter, which consists of 616 PMTs (photomultiplier tubes) and 1848 dynode signals, is a crucial part of the DAMPE payload for measuring the energy of cosmic ray particles, distinguishing interesting particles from background, and providing trigger information. An electronics system, which consists of 16 FEE (Front End Electronics) modules with a total power consumption of about 26 W, has been developed. Its main functions are based on the low power, 32-channel VA160 and VATA160 ASICs (Application Specific Integrated Circuits) for precisely measuring the charge of PMT signals and providing“hit”signals as well. To assure the long-term reliability in harsh space environment, a series of critical issues such as the radiation hardness, thermal design, components and board level quality control, etc., are taken into consideration. Test result showed that the system level ENC (equivalent noise charge) for each channel is about 10 fC in RMS (root mean square), and the timing uncertainty of the hit signals is about 300 ns, both of which satisfy the physics requirements of the detector. Experiments with 60 Co radioactive source proved that 20 krad(Si) TID (Total Ionizing Dose) level is achieved, while the heavy ion beam and laser beam tests indicated that its SEL (Single Event Latch-up) and SEU (Single Event Upset) performance in orbit will be acceptable by taking some hardness measures. All the readout modules successfully passed the board-level screening, the sub-system level and finally the satellite system level environmental tests, and behave well in the beam test at CERN (European Organisation for Nuclear Research).

A time-of-flight (TOF) readout system has been developed for a Beijing Spectrometer (BES III). This paper will present an overview of the entire TOF readout system design and its performance in the operation. In a BES III TOF detector, a total of 448 photomultiplier tubes (PMTs) have been installed in barrel and end-cap sections. The corresponding 448 channels' readout electronics aimed precisely to measure the arrival time of PMT signals from the TOF detector is mainly housed in two VME64xP crates, each crate containing 14 FEE modules, 14 FEE_rear modules, one Fast Control module (FastCtrl), one Clock module, and one Power-PC interface module. Due to the structure of the spectrometer, the two VME crates with 448 channels of readout electronics are placed in two locations; each is 18 m away from the TOF detector. In order to increase the capability of noise immunization and achieve better signal-to-noise ratio, each channel has a preamplifier equipped to PMT base. The preamplifier drives the differential signals over 18 m of shielded twisted-pair cables to the VME crates. The readout system achieved a timing resolution of 25 ps after time-walk and INL corrections. The amplitude-dependent time-walk correction is accomplished by measuring corresponding pulse height. Achieved pulse-height resolution is better than 10 mV in a dynamic range 180-5000 mV. The whole TOF readout system was installed in the spectrometer and has been in operation steadily since then, with the performance well meeting the requirements of the physics experiments.

The TOF (Time-Of-Flight) detector in BES (Beijing Spectrometer) III experiment requires a total time resolution of better than 90 ps (for the barrel part) and 110 ps (for the endcap part). With the requirement of such a high precision time measurement, it is essential to measure the amplitude or charge of the PMT (photomultiplier tube) signals, in order to correct the amplitude dependent time-walk. A method of using non-gated QTC (Charge-to-Time Converter) to measure the input signal charge was developed for BES III TOF readout electronics. The non-gated QTC with differential inputs was designed to measure the input charge covering a dynamic range of about 30–927 pC. Test results showed that the rms resolution is better than 10 bit and the relative error is less than 0.5% after quadratic fitting. The designed converter is simple, stable and suitable for multi-channel systems. A total of 448 channels of QTCs have been developed for BES III TOF readout electronics, which help the TOF system achieve the expected time resolution after the time-walk correction.