Milestone progress of the HEPS booster commissioning

The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in China.The HEPS injector consists of a linear accelerator(Linac)and a full energy booster.The booster captures the electron beam from the Linac and increases its energy to the value required for the storage ring.The full-energy beam could be injected to the storage ring directly or after“high-energy accumulation.”On November 17,2023,the key booster parameters successfully reached their corresponding target values.These milestone results were achieved based on numerous contributions,including nearly a decade of physical design,years of equipment development and installation,and months of beam commissioning.As measured at the extraction energy of 6 GeV,the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm rad with a single-bunch charge of 5.58 nC,compared with the corresponding target values of 6.6 mA and 35 nm rad,respectively.This paper presents the physical design,equipment development,installation,and commissioning process of the HEPS booster.

Research on magnetic centermeasurement of quadrupole and sextupole using vibrating wire alignment technique in HEPS-TF

Purpose In order to meet the extremely low emittance requirement,the magnets in the storage ring of high-energy photon source(HEPS)need to have a stable support and precise positioning.In HEPS-TF,the key and difficult technologies of HEPS should be researched and developed.Vibrating wire alignment technique is one important project of HEPS-TF.It can be used to pre-align the quadrupoles and sextupoles on one girder with high precision.A vibrating wire measurement system was set up and tested to verify the magnetic center measurement precision and the magnet adjustment error.Methods There are one sextupole and one quadrupole installed on a multipole girder.Vibrating wire is stretched through mechanical center of the magnet apertures and supported by the test benches on the two sides.A single conducting wire is stretched through themagnet aperture and electrified by alternating current.The wire will vibrate for a period of Lorentz force.By matching the current frequency to one mode of natural frequency of the wire,the vibrating amplitude will be enhanced.And by measuring the vibrating amplitude,the magnetic field at the wire position can be got.Moving the wire across the magnet aperture in the transversal or vertical direction,the distribution of magnetic field and magnetic center position can be measured.According to the magnetic center position error to adjust the magnet.Measure the magnetic center of all magnets installed on the multipole girder one by one,and adjust their magnetic center to a line.Results The magnetic center measurement precision is better than±3μm,and the magnet adjustment error is less than 6μm.Conclusion The vibrating wire system design and a series of magnetic center measurement experiments have gained good achievements.It has been proved the vibrating wire system is designed reasonable and using the vibrating wire to align the magnets installed on a multipole girder is feasible and can reach a high precision.