#### Control System Specification for a Cyclotron and
Neutron Therapy Facility

Jonathan Jacky, Ruedi Risler, Ira Kalet, Peter Wootton,

Alexandra Barke, Stan Brossard, and Ralph Jackson

May, 1991

**Abstract**

It is usually considered an essential element of good practice in engineering
to produce a specification for a system before building it. However, it has
been found to be quite difficult to produce useful specifications of large
software systems. We have nearly completed a comprehensive specification for
the computer control system of a cyclotron and treatment facility that provides
particle beams for cancer treatments with fast neutrons, production of medical
isotopes, and physics experiments. We describe the control system as
thoroughly as is practical using standard technical English, supplemented by
tables, diagrams, and some algebraic equations. This specification comprises
over 300 single-spaced pages. A more precise and compact specification might
be achieved by making greater use of formal mathematical notations instead of
English. We have begun work on a formal specification of our system, using the
Z and Petri net notations.