Development Of Ultra-high-speed And High-precision Waveform Digitization Circuit Based On DRS

Many experiments at large gas pedals such as the Heavy Ion Research Facility at Lanzhou(HIRFL)and the High Intensity heavy-ion Accelerator Facility(HIAF)require the use of plastic scintillator detectors(PSDs).Plastic Scintillator Detector(PSD)is mainly used for heavy ion research,particle identification,low background counting,inverse compliance and dosimetry experiments.Since the output of most PSDs is a narrow pulse charge signal with a pulse width of only a few tens of nanoseconds,high speed extraction and data processing of these output narrow pulse charge signals is essential to meet the requirements of high resolution and multiparameter measurements of PSDs.The waveform digitization technology based on Switched Capacitor Array(SCA)is an important development direction for the extraction and processing of electrical signals output from detectors in modern gas pedal devices.In this paper,we design an ultra-high-speed waveform digitization data acquisition circuit based on the DRS4(Domino Ring Sampler 4)chip of SCA,where the narrow pulse charge signal from the PSD is extracted by an analog conditioning circuit and converted from singleended signal to differential signal,then the differential signal is sampled at high speed,stored and read out at low speed by the DRS4,and then passed through an analog-todigital converter(Analog-to-Digital Converter).The digital signal is processed by the Field-Programmable Gate Array(FPGA)after the Analog-to-Digital Converter(ADC),and the Digital-to-Analog Converter(DAC)provides the bias.In addition,the DAC provides the bias voltage and the threshold voltage of the voltage comparator of the trigger circuit,and the trigger circuit generates the trigger signal by comparing the input signal and the threshold voltage of the voltage comparator provided by the DAC to control the readout of the valid signal.The operating mode of the readout board can be configured online by the upper computer(IPC)through the USB(Universal Serial Bus)interface,and an optical module interface is reserved for high-speed information transmission.This circuit is able to reconstruct and restore the detector output signal waveform from the acquired data,and display the amplitude and time information of the detector obtained waveform visually.The main function of this design is to sample multiple high-speed input signals from 700 MHz to 5GHz with adjustable sampling frequency,store them through switched-capacitor arrays,and then output the stored voltage signals to ADC for analog-to-digital conversion at low speed.The circuit not only solves the problem of difficult extraction of high-speed signals,but also solves the problem of analog-to-digital conversion of high-speed signals using low-speed highprecision ADCs.Moreover,the host computer can control the sampling frequency and sampling depth of DRS4 by sending commands to the FPGA via USB,so that the combination of sampling frequency and sampling depth can be adjusted more flexibly,which greatly meets the processing needs of input signals with different pulse widths and enables it to adapt to a variety of application scenarios.Performance tests show that the circuit’s sampling rate is adjustable from 700 MHz to 5GHz,the distortion error is less than 0.7d B in the analog input bandwidth from 0 to 200 MHz,the noise of the channel is less than 0.5m V,and the Integral Non-Linearity(INL)is better than 1%.The data acquisition circuit has certain versatility and is suitable for detector readout in many types of physical experimental devices.