Beam Detection Using Residual Gas Ionization

The nondestructive beam detector systems originated at Argonne National Laboratory allow continuous measurement of the proton beam position and beam profile in the Zero Gradient Synchrotron (ZGS) during the accelerating and targeting cycle. Nondestructive detection is accomplished by collecting the ions produced by the proton beam ionizing residual gas in the vacuum chamber. The amplitude of the electrical currents obtained by collecting these ions onto a variety of electrodes depends on the distribution of the protons in the beam. The characteristics of the electric signals make them suitable as inputs to computer systems. Both analog and digital techniques have been used to determine beam position and profile. These beam detection systems have been used for measuring the properties of the 50 MeV beam between the injector linac and the synchrotron ring; for studying the steering and the radial growth of the size of the beam during acceleration; and for measurements during the targeting sequences.