The 2-7GeV high intensity electron-positron accelerator (HIEPA), as one of the options for the new generation of particle physics test facility in China, is currently under pre-research stage. High energy resolution electromagnetic calorimeter (EMC) for measuring the energy and direction of photons and electrons is one of the important components in an accelerator. This abstract presents a front-end readout ASIC with high counting rate, and high dynamic range, which is designed for EMC. The ASIC is fabricated using TSMC 0.18-μm CMOS technology, and used for APD detector whose parasitic capacitance is 270pF. The readout channel is comprised of a charge sensitive amplifier (CSA), two CR-RC2 shapers, two peak-detect-and-hold (PDH) circuits, a gain select circuit, a fast shaper, a discriminator and a readout buffer. The input range of the ASIC is from 0.4fC to 1000fC, reflecting to the energy level from 1 MeV to 2500 MeV. For this large input range, the readout channel has two branches after the charge-sensitive amplifier (CSA), high gain branch and low gain branch, and using the gain select circuit to choose which one is output. In the simulation, the readout channel counting rate is 200KHz with the peaking time can be adjusted from 0.5us to 1.5us. The readout channel is optimized for 270pF of input capacitance, and the verified result of signal to noise ratio (SNR) achieved 4 at 0.4fC input charge. The linear error is less than 3%, and the power dissipation is about 10mW/channel.
|Submission declaration||Original and unpublished|