Multi-Channel Data Acquisition And Control System For The Study Of Cluster Characteristic

The Nuclear Data Acquisition and Control System are the important tools in both basic and applied researches, such as High Energy Physics, Nuclear Physics, Atom-molecule Physics, Nuclear Astronomy Physics and Application of Nuclear Technology. The constituent mode and performance of this system not only effect the precision and results of the experiment directly, but also determine the time and outlay of this experiment. In recent years, with the rapid development of the study in the field of Atom-molecule Physics, the experimental equipments turned into larger and larger, the number of the parameters needed to be detected increased, the precision of measurements was improved, the measuring and controlling distance was expanded. As the results, more and more serious requirements were raised to the nuclear data acquisition and control system. In order to meet these requirements and to support the advanced study of the interaction between clusters and materials, a key project supported by China National Science Foundation, we have done the study of the data acquisition and control system for the clusters characteristic in detail, and employed single-chip microcomputers and PC computers to compose a large scale data acquisition and control system. The composition mode of this kind of system and the distribution of tasks, the acquisition and control circuit units based on single-chip microcomputers, the real-time communication methods and the software composition under the Windows 98 were also discussed in detail.This distributed system was consisted of three layers. The first layer is data acquisition and control circuit units which are primarily composed of single-chipmicrocomputers, CPLDs and designed according to the standards of NIM modules so as to attain the acquisition and control of the data of multi-parameters and to make this kind of NIM to be able to communicate directly with upper PC computers. The second one is PC computers which are used to respond and control the multi units of data acquisition and control. The first and second layers consist of a independent sub-station to perform the acquisition and processing of the data of multi-parameters. Many sub stations can be further connected together through a LAN and constitute the third layer. This system can acquire and process a lot of different data from wide ranges.As single-chip microcomputers, CPLDs and PCs are connected into groups and run in parallel mode in this distributed system, it avoid the limitation of functions caused by their single run and acquires/process data in cooperation and high rate. This Distributed Nuclear Data Acquisition and Control System (DNDACS) with three layers gives the data acquisition and processing ability as strong as the system based on the giant or middle computers. This system has put into operation in the device of Atom-molecule Collision at Sichuan University stably and satisfactorily. It provides the ordinary laboratories with simple and economical way to build their own powerful DNDACS.