Calibration of phase detector using IQ modulator

Miyao, Tomoaki*; Miura, Akihiko ; Kawane, Yusuke*; Ouchi, Nobuo 

The beam energy of the J-PARC Linac is calculated by TOF (Time-of-Flight) method with the flight distance and the beam phases measured at the two phase monitors. Because the accuracy of the beam energy calculation is directly depending on the errors in the phase measurement system, all beam phase monitors are calibrated annually. We have decided to use an IQ modulator circuit to realize the high accurate calibration and to reduce the calibration time. We describe the original and new procedure of the energy calculation in this paper.