K. Zheng

Bunch-by-bunch measurement and feedback system of HLS

In this paper, HLS (Hefei light Source) bunch-by-bunch measurement and feedback system will be introduced. This system is integrated with longitudinal oscillation measurement system, fast vector control, fiber notch filter and bunch current detection system. The detail of the two fronts will be shown. Some experimental results by this system are also present in this paper, as phase-space tracing, mode dumping rate, and feedback experiments.

Bunch Tracing by Bunch by Bunch Measurement System in HLS

In this paper, we introduce a bunch tracing system which is based on a bunch-by-bunch (BxB) measurement system in Hefei Light Source (HLS), and present the analysis of the experiment results. Using an in-phase gate signal and a double balance mixer to control an external trigger of ADC, we test the reliability of the BxB system. By this system, we can trace all marked bunches in a set time slot or in manual burst mode. We can record all bunches’ data during the injection, ramping, wiggler excitation and normal operation, and provide a powerful facility for machine study.

Development of Measurement and Transverse Feedback System at HLS

In order to cure and damp coupled bunch (CB) instabilities caused by the high order modes (HOMs) of the RF cavity and the resistive wall impedance of the Ring vacuum chamber. HOMs are ineluctable during the operation of the accelerator. An observer system characterized by bunch by bunch measurement of transverse β oscillation and longitudinal synchrotron phase oscillation has been constructed and commissioned at Hefei Light Source (HLS) [1, 2]. A transverse bunch-by-bunch feedback system is under construction. The design and development of the observe systems, as well as diagnostics results of machine instabilities are presented in this paper.

Optical-fiber notch filter for storage ring transverse feedback system

An optical-fiber two-tap FIR (Notch) filter has been developed for storage ring transverse feedback system of Hefei light source. The optical notch filter has advantages of low loss, which is not related to the size of the storage ring, high-frequency response, and compact in size. Measurements have been done with storage ring beam signals. The paper presents the principle and the experimental results.

Development of transverse feedback system and instabilities suppress at HLS

In order to cure and damp coupled bunch instabilities (CBI), a bunch-by-bunch (BxB) measurement and transverse feedback system is under commission at Hefei light source (HLS). In this paper we introduce the overview of the measurement and analogy transverse BxB feedback system in emphases. The measurement system is dedicated to observe the beam instability and works as a part of the analogy and digital transverse BxB feedback system. The development of several characterized components and stripline feedback kicker as well as the experiment result of the feedback system in HLS ring is also presented in this paper.

Development of digital transverse bunch-by-bunch feedback system of HLS

Hefei light source (HLS) operates at high beam current with many bunches. Multi-bunch instabilities degrade beam quality. An FPGA based digital transverse bunch-by-bunch feedback system was under development in HLS to suppress beam instabilities. The design of the digital feedback system and primary experiment results are presented in this paper. Further improving of the feedback system and investigating of the characteristics of the feedback loop are the future work.

The Measurement of Tune and Phase Space at HLS

Tune and phase space online monitor at the electronic storage ring of Hefei Light Source (HLS) has been implemented by using Turn-by-turn Beam Position Monitor System (TBT System). In this paper, we compare a number of methods employed to compute tune and deals with choosing the best fitting method for our online tune computing. We can compute and display tune online, at the same time, record beam tracks on the transverse phase space by using turn-by-turn beam position data at two differently-located beam-position-monitor electrodes. With these instruments we can precisely and attractive study machine instabilities.

Beam instabilities measurement and cures at HLS

In Hefei light source (HLS), coupled-bunch instabilities are major limiting factors in achieving higher beam intensity while maintaining good beam quality. To Measure and suppress beam instabilities, turn-by-turn (TBT) measurement and bunch-by-bunch(BxB) measurement & feedback system are under commission [1][2]. The design of the two systems and primary experiment results is presented. Measurement and detail analysing results in injection status will also be shown.

Development and Application of Bunch-By-Bunch Measurement System of HLS

This paper is intended to present the newly implemented wideband (100MHz) bunch oscillation measurement system, which is in nature a different method from the narrow-band (< 5MHz) facilities employed before. Basic formalism and implementation details of the system is introduced to illustrate the function of observing coupled bunch instabilities in time and frequency domain. The designed function includes detecting of transverse oscillation, synchrotron phase oscillation, as well as bunch filling pattern. Some diagnostics results of machine instabilities and application of this system are also discussed.

HLS Turn-by-Turn System and its Application

Measurement principles and analysis of Turn-by-Turn beam position monitor system at Hefei Light Source (HLS) are presented in this paper. In emphases, several typical applications are presented here, which include the commissioning of upgraded injection system on HLS storage, monitoring of transientν transientν transientν transientν transientν transientν transientν transientν transientν transientν and damping time of storage ring, beam instability in injection, as well as experiments of low frequency feedback system. Precise analyses of experimental results offer some conclusions, which are consistent with theoretical expectations. The system plays an important role in study of beam instability and improvement of machine performance.