An automated dose mapping system for the TRIUMF biomedical pion beam.

The dosimeter used in a transmission ionisation chamber and as the measurement is by charge integration, the sensitivity is limited only by the total leakage current of the detector, signal cable and electrometer. A minicomputer is used for on-line control of and data acquisition from the dosimetry system. Computer control also makes possible changes in the beam tune during dose mapping as is required in dynamic control of the momentum. Continuous monitoring of all the beam line elements by the same minicomputer can result in terminated or rejected dosimetry in the case of component failure. Direct computer storage of the dose maps facilitates software manipulation of the data.