Zeff first measurements in EAST with a multi-channel visible bremsstrahlung new system

• In this paper, we mainly introduced the bremsstrahlung measurement system for Zeff in EAST.
• Some correction and new calibration method were applied in the measurement in order to improve the measurement accuracy.
• Preliminary experimental results prove the system is valid and reliable.

A multi-channel visible bremsstrahlung measurement system was developed to measure the ion effective charge (Zeff) in EAST tokamak. The system has a temporal resolution of 0.05 ms and spatial resolution of 3 cm. The measurement principle and the design of the 8-channel fiber-photomultiplier tubes (PMTs) coupled system are described, including the calibration process of the measurement system with an integrating sphere. Preliminary experimental results of line integrated bremsstrahlung profile and Zeff derived from the system are reported.