Application of an X-ray flat panel sensor to a GeV region gamma-ray beam profile monitor

A beam profile monitor for 1-GeV region gamma-ray beams has been developed using an X-ray flat panel sensor. In order to increase its sensitivity to gamma-rays, a converter plate was placed on the input window. We tested its sensitivity to input gamma-ray photons with various types of converter plates. The output brightness of the pixels was found to be correlated to the number of electrons and positrons converted from the gamma-ray photons. A measured profile of the 1-GeV region gamma-ray beams obtained with a 1-mm thick lead plate was consistent with the beam profile measured with plastic scintillator hodoscopes. It suggested that the X-ray flat panel sensor was sufficiently applicable to the beam profile monitor for 1-GeV region gamma-ray beams.