A beam test of button-type beam position monitor for the ATF damping ring

The Button-type Beam Position Monitors (BPMs) were fabricated for the ATF damping ring. The BPM was designed to achieve the position resolution less than 5 μm, and the fabrication of the first 40 BPMs was completed. For this BPM, a beam test was carried out at the 80 MeV injector part of the ATF LINAC. All of bunch signals in multi-bunch beam were clearly observed without any discharge. The calibration of BPMs was also performed to check their offset from the electrical center to the mechanical center and their position detection sensitivity. The result shows a good uniformity of position detection