HEPS is a fourth generation light source which has horizontal emittance around 34pm.rad and high brilliance photon beam, this ultra-low emittance brings many engineering challenges for beam instrumentation. Self-developed digital BPM electronics and scintillate BLMs contributed more in first turn and day one commissioning. The gird designed by combining carbon fiber and invar alloy have effectively suppress the long drift of the BPM system. Additionally, synchrotron radiation measurement system based on KB mirror has successfully captured the first synchrotron light and provided real-time beam size measurements. This talk will present an overview of beam instrumentation of HEPS.

The vertical beam size measurement was carried out at BEPCII using a phase grating and an absorption grating based on the Talbot effect. Due to the partial coherence of the source, coherence length can be calculated by measuring the visibility decay of interferograms recorded at different distances behind gratings. The vertical beam size of 68.19±2μm was obtained based on the relationship between coherence length and source size. A comparison of the vertical emittance derived from grating Talbot method and synchrotron radiation visible light interferometer method was presented to evaluate the method. The vertical emittances from two methods are 1.41nm·rad and 1.40nm·rad respectively. The 0.1% difference indicates the grating Talbot method for beam size measurement is reliable. This technique has great potential in small beam size measurement in the fourth-generation synchrotron radiation light source, considering its small diffraction limitation and simple experimental setups.

High Energy Photon Source (HEPS) is a 6 GeV dif-fraction limited storage ring light source. An ultralow emittance of ~34 pm·rad is designed with a multiple-bend achromat lattice at storage ring. The transverse beam sizes at the dipoles will be less than 10 µm. In order to measure such small beam sizes in both directions, an X-ray beam diagnostic beamline is designed with bend-ing magnet as source point. X-ray pinhole imaging and KB mirror imaging are used compatibly and comparably to capture beam image. A visible light beam diagnostic beamline is designed to measure bunch length with streak camera. During the first phase storage ring commissioning time, both diagnostic beamlines captured the first light.