NEW METHOD FOR VIBRATION MEASUREMENT AND CONTROL OF MOVING WIRE

On-line measurement and control method of moving wire vibration are developed. The response measurement of the wire is indirectly accomplished by 'vibration transfer method ' and active con- trol is carried out on the vibration receiving body by piezoelectric ceramics. The fundamental princi- ples of measurement and control are stated and experimental results are presented.

Analysis and experimental concepts of the vibrating wire alignment technique

The vibrating wire alignment technique is a method which, by measuring the spatial distribution of a magnetic field, can achieve very high alignment accuracy. The vibrating wire alignment technique can be applied to fiducializing magnets and the alignment of accelerator straight section components, and it is a necessary supplement to conventional alignment methods. This article gives a systematic summary of the vibrating wire alignment technique, including vibrating wire model analysis, system frequency calculation, wire sag calculation, and the relation between wire amplitude and magnetic induction intensity. On the basis of this analysis, this article outlines two existing alignment methods, one based on magnetic field measurement and the other on amplitude and phase measurements. Finally, some basic experimental issues are discussed.

Preliminary R&D of vibrating wire alignment technique for HEPS

The alignment tolerance of multipoles on a girder is better than ±30 μm in the storage ring of the High Energy Photon Source （HEPS） which will be the next project at IHEP （Institute of High Energy Physics）. It is difficult to meet the precision when only using the traditional optical survey method. In order to achieve this goal, a vibrating wire alignment technique with high precision and sensitivity is considered to be used in this project. This paper presents some preliminary research works about theory, scheme design and achievements.

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.