The Readout Electronic Of Gas Detector Based On TDC-Chip

Time is one of basic physical quantity in the experiment of the nuclear physics and particle physics. Time measurement is most important in measurement of the nuclear electronic, too. When incident particles come across the detector, they loss energy, interact with matter and produce ionization, inspire, photoelectric conversion, the nuclear reaction, etc. Under the electric field, the charged ions drift to the collection, and give the signals which will be processed by the front-end electronics. We can get the information of the particles by measuring time, and analyze the incident particles’ charge, quantity, type, quality and momentum from energy spectrum analysis system that measures the change and time analysis system that measures the time. This provides a basic for analyzing characteristics, internal structure of particles, and discriminating the particle. The high precision time measurement plays an important role in getting physical information and reflecting the laws of material movement correctly.Gas detector is widely used in high energy physics, nuclear physics, medicine physics, and other detection field. It always measure the track of particle and loss of energy. We use the ASIC-SFE16 which is based on TOT technology to discriminate a certain width of pulse level signal. With the charge sensitive preamplifier, pole zero cancellation forming circuit and filter circuit, the input signal is deal with the time to digital converter that is high resolution and precision. Thus, we can use less device to design the system by using the TDC. Absolutely, it makes the system much easier to maintain.In the article, we analyze kinds of the technology of time measurement and choose TDC chip which is low cost, simple circuit structure and widely applied to complete the measurement of time. By using TDC chip produced by ACAM Company, we design 32 channels charged and time of flight measurement system. The test results show that this TDC system achieves a time resolution of 55 ps and a good linearity. The system which has the high performance electronics module circuit, low cost, portable and has large measuring range, is applicable to a variety of gas detectors. At last, we introduce work on realizing precise time to digital converter by using the dedicate carry chain of FPGA. The TDC designed by FPGA is low cost and can be used by Wave-Union to achieve high resolution.