TRIUMF injection line nonintercepting beam energy monitoring through phase measurement

A nonintercepting beam velocity monitoring system has been installed in the 300 keV injection line of the TRIUMF cyclotron to reproduce the injection energy for different ion source beams and monitor any beam energy fluctuations. The monitor is tuned to resonate at 46 MHz and is 3.25 m downstream from the first 23 MHz buncher. The phase difference between the first buncher and the pickup is related to the average beam velocity, i.e., beam energy. The energy sensitivity of the measurement is 1×10−4. The dynamic range of the monitor with beam current is 60 dB, and the measured instantaneous beam intensity can go down to 100 nA. The theory behind the device and the results of beam tests will be described.