1. Introduction
Since early 1966, Yale and IBM Research have been engaged in a joint study in the application of computers to nuclear-data acquisition. The main goal was the production of an integrated hardware-software system which is fully under the control of the experimenter in the sense that he can define his entire data acquisition and analysis process with a Fortran program.
The joint study may be divided into four areas: (1) Development of a suitable general and powerful data-acquisition interface and control unit (front end) with a set of compatible nuclear instrumentation modules (scalers, ADC's, and general-purpose input registers). (2) Development of a suitable display system. (3) Development of a data-acquisition language (as an extension to Fortran) and the necessary library routines to support this language. (4) Development of a general-purpose multiprogramming system for the selected computer (the IBM System/360, Model 44) into which the data-acquisition system could be incorporated.
The first three areas became operational in July 1967, within three months after delivery of the computer, using the standard batch programming system for the 360/44 as a basis. Development continues on the multiprogramming system, which has now reached a state where users inexperienced in using the system can compile and execute Fortran programs, but the data-acquisition components are not yet operational.
2. Description of the System
Nuclear data are input by means of a general-purpose nuclear-data-acquisition interface and control unit, organized around the concept of an event, an occurrence in the real world which causes the outputs of a group of instruments selected by the user to be read into computer memory. Sixteen independent events are provided for, with each of which may be associated any or all of 30 different instruments (scalers, ADC's, or general-purpose monitor registers) by means of a diode plug board matrix. The instruments themselves, also designed and built by IBM, are modular and completely interchangeable and enable the experimenter to configure his experiment in any way desired, i.e., to determine not only which instruments are to be read but also in what order. Exclusion logic is provided to prevent processing of certain events if and when other defined events occur simultaneously (Figure 7).
The cathode-ray-tube display unit provides a 1024 x 1024 point plotting oscilloscope with seven levels of intensity, character-generation hardware, a light pen, and a programmed function keyboard, by means of which the user can call in programs by pushing buttons. Such programs can perform any function from changing displays gains to curve-fitting. They may be system-supplied or user-written and may be (and usually are) written Fortran. A parallel, high-resolution photographic system permits computer assembly of publication quality illustrations.
The data-acquisition and display-programming system is composed of a group of subroutines which may be called from Fortran programs for performing the various processes in data acquisition and display. For this purpose, a considerable number of additional statements have been added to the Fortran language. These statements perform such functions as defining multidimensional pulse-height analyzers in the computer memory, performing pulse-height analysis using incoming data as channel numbers, and defining separate programs to process each of the 16 classes of input events. All the special statements that make up the new data-acquisition language are implemented by means of a preprocessor which converts them into Fortran coding, which the standard 360/44 Fortran compiler then processes.
