Operational Aspects of a Serial CAMAC Control System

The NAL accelerator achieved design energy of 200 GeV on March 1, 1972. Since that time, the main accelerator has operated as high as 400 GeV and regularly operates at 300 GeV. The highest intensity to date has been 1.8 × 1012 protons per pulse at 300 GeV. This beam has been extracted from the accelerator using a half-integral resonance system to give a slow spill over approximately 250 ms. The extracted beam is presently being split and sent into three different experimental areas. In addition, a target area in the main accelerator enclosure allows experiments to be done on the internal, circulating beam.

Operating Results from NAL

The main accelerator abort system is designed to dump the unwanted beam only around the abort system and to reduce the residual radioactivity around the accelerator. The system consists of a 9-ft long aluminum target, a pair of 20-ft long steel collimators, and a pair of fast bump magnets. The beam is aborted within a few milliseconds after the arrival of a trigger signal.

Main Accelerator Abort System

Introduction The execution of a data transfer on this link is initiated by a command function on the standard data link. The MDC receiver, upon receipt of a 16 bit data word, will send a service request to the MDC which idles the CPU between instructions, initiates a read cycle, and stores the word in mIemory. The operating program automatically resumes execution after each request is serviced. Upon receipt of the prescribed number of data words in memory, the computer is automatically interrupted to process the data. This link allows data to be transferred from devices into memory at a 40 KHz word rate independent of programmed instructions, thus allowing the normal operating program and serial data link to function uninterrupted. Figure 1 is a block diagram of the 8 GeV/Switchyard Control System. The diversification and physical remoteness of components constituting the NAL proton beam switchyard and site-wide fire detection systems necessitated the use of mini-computers to centralize monitoring and control. Devices are interfaced to the computers by series connected local controllers. The local controllers utilize a standard CAMAC crate with a simplified dataway to achieve economic modular construction. Serial data transfers are used between controllers for reliable operation in a high noise environment. Bulk data transfers to the Switchyard System Computer are implemented on a special high speed serial link which operates independent of, but initiated by, the local controllers. A special Minicontroller module with an emergency back-up power source is used to monitor NAL fire detection

W. H. DeLuca

Papers

Main Accelerator Abort System

A Modular Control System Utilizing CAMAC Hardware for Interfacing Remote Components at NAL