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High Energy Photon Source (HEPS) is a 6 GeV ul-tralow-emittance storage ring light source to be built in Beijing, China. With a multiple-bend achromat lattice design, the storage ring is expected to achieve an ul-tralow emittance of 34 pm.rad. The horizontal and verti-cal beam sizes will be in the sub-10 μm level. Beam emit-tance will be measured with x-ray diagnostic beamline at a low dispersion bending magnet source point. A visible light beamline will be designed to measure the bunch length and purity. In this paper, we will introduce the x-ray beamline, which combine with different techniques to resolve beam sizes and emittance., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Model Independent Analysis (MIA) is a beam analysis method applied for Turn-by-Turn (TBT) Beam Position Monitor (BPM) data. To develop the commissioning method of the HEPS storage ring, we simulate application of MIA on HEPS storage error model to measure and cor-rect the optics parameters. Difficulties and limitations of the MIA method are also discussed., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

The 4th generation ring-based light sources, HEPS (High Energy Photon Source) 7BA lattice has been de-veloped at IHEP. This is 6Gev, 200mA machine which has horizontal emittance Ɛh around 60pm.rad to gain the high brilliance photon beam. this compact lattice design bring so many engineering challenges for accelerator magnets, vacuum components, beam diagnotice, etc. This paper will present the noval lattice design and subsystem design progress., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Beam profile determination at high intensity hadron accelerators implies the usage of non-invasive methods. The transverse profile of the beam is monitored via detecting the ionization products produced by the collision of proton with residual gas in the vacuum pipe. High voltage electrodes are used for producing guide electrical field and MCP for amplify the signal. The screen and CCD system are used for position detection. An ionization profile monitor is designed and manufactured. It has been installed on the ADS injector I. The signal intensity of ionization products matches the theory's expectation. Experiments result shows that it is a useful tool to measure the profile of proton beam., Proceedings of the 6th Int. Beam Instrumentation Conf., IBIC2017, Grand Rapids, MI, USA

The injector I of China Accelerator Driven Subcritical system (C-ADS), which is composed of an ECR ion source, a low energy beam transport line (LEBT), a radio frequency quadrupole accelerator (RFQ), a medium energy beam transport line (MEBT) and cryomodules with SRF cavities to boost the beam energy up to 10 MeV. The injector linac is equipped with beam diagnostics. Cold beam position monitor(BPM) is one of instrumentations of the injector. This paper describes the design and fabrication of the cold BPM pick-ups, and also the application of the BPM in commissioning of SRF cavities. Discussion of the promotion and other aspect will also be presented., Proceedings of the 6th Int. Beam Instrumentation Conf., IBIC2017, Grand Rapids, MI, USA

This paper introduces the necessary design parameters of transverse feedback system. Meanwhile, it mainly contains the design of stripline as feedback system kicker. The transverse kicker has 4 striplines, so that it can work in vertical and horizontal area. In the experiment, the shunt impedance is 1500 Ω which is simulated by HFSS and the system only need 120W to suppress the coupled beam bunch instabilities. According to the results of parameter S (1, 1) and S (2, 1), power loss and reflection is convenient. Recently, the prototype is calibrated., Proceedings of the 6th Int. Beam Instrumentation Conf., IBIC2017, Grand Rapids, MI, USA

Non-uniform bunch fill patterns in storage rings, driven by the need to provide gaps for beam aborting and ion clearing cause a large beam loading change in the RF cavities. The induced turn-periodic transient in the cavity voltage modulates longitudinal beam properties along the train, such as synchronous position and bunch length. In the EIC design, due to the asymmetric bunch train structure between the electron and the ion beam, such modulation results in shifting collision point and leads to reduced luminosity. We have carried out the beam based experiments at BEPC-II and ALS using bunch-by-bunch diagnostic capabilities of the coupled-bunch feedback systems to study this transient effect. A modulated bunch filling pattern with higher charge density around the gap has been demonstrated to be effective in partially compensating this transient modulation. Details of the experimental setups and the data analysis will be presented to this conference., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Synchrotron radiation facilities are indispensable in numerous forefront areas. Until now, the electron energies of all photon sources in China have been in the medium- and low-energy regions. However, research related to national security and industrial innovation has demonstrated the urgent need for high-performance sources with high electron energy. For this purpose, a complex for advanced photon sciences in northern China has been planned since 2009 [1]. The complex is planned in three phases. In the first phase, a storage-ring-based, high-energy photon source (HEPS) with a beam energy of 5 GeV and emittance less than 1.0 nm•rad will be constructed, which can provide high-brilliance hard X-rays to several tens of experimental stations. In the second phase, a superconducting linac will be constructed to drive an X-ray free electron laser (XFEL), serving as an extension and compliment to the HEPS. In the third phase, as one possible performance upgrade scheme, the ring and the superconducting linac will...

To calibrating a cosmic-ray detector, a low beam current accelerator has been built to generate ultra low intensity electron beams at Institute of High Energy Physics (IHEP). The minimum beam charge obtained was estimated to be about one electron/pulse. Beam commissioning has been carried out. The key technologies for achieving such low intensity electron beams are to control the beam using 8 movable slits and to measure the intensity of the beam using 9 movable current monitors based on scintillator. In this paper, principal of operation, instrumentation and programming of the movable slits and movable current monitors are discussed. Some results of beam commissioning are also presented., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

For some detectors' calibration, a very weak electron current provided by accelerator is necessary. In order to control the beam current to the detector, 8 movable slits in which the position resolution of the stoppers is better than 5μm are installed along the accelerator. For the weak current measurement, 9 movable current monitors based on scintillator are installed along the beam line. These monitors can measure the very weak current, even to several electrons. The monitors can be pulled away the beam axis when the electron beam goes to the downstream., Proceedings of the 5th Int. Beam Instrumentation Conf., IBIC2016, Barcelona, Spain

A Solid State Amplifier (SSA) has been developed for testing beam feedback system of the BEPCII of the Institute of High Energy Physics (IHEP), CAS. The output power of the SSA is 100 W with a CW frequency range from 1000 MHz to 1250 MHz. After three generations development, the SSA has become a professional power source. The paper has introduced the development of the SSA and the skills used in the SSA., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

For the third-generation light sources, the vertical emit-tance of a few pico-meter-radians which can be achieved with good coupling correction close to 0.1%, will lead to very small beam size. Several microns vertical beam sizes measurement has presented challenges for diagnostic capability in this region. A few techniques have been developed to make a precise measurement, such as visible light interferometer, x-ray imaging using Fresnel zone plates, compound refractive lenses or pinhole camera. In this paper, an x-ray reflective optics method based on the Kirkpatrick'Baez mirrors will be emphasis on discussed. The K-B mirror system will be installed and tested in SSRF to obtain the vertical beam size close to 20 microns, which is expected to be used for several microns vertical beam size measurement in the future light source named HEPS (High Energy Photon Source) in China., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

For proton linac, phase and energy measurement is very important. Beam phase always can be measured by quadrature sampling, energy can be measured by the method of time of flight (TOF), in this way we need to know the beam phase of two points whose distance is given. C-ADS injector I is a 10MeV proton linac with 10mA continuous current. It consists of an ECR (Electron Cyclotron Resonance) ion source, a LEBT (Low Energy Beam Transport), a 3MeV RFQ (Radio-frequency Quadruple) and a superconductivity linac accelerator with 3~10MeV. In the initial phase, the beam energy is about 3MeV. In this paper, phase and beam energy system of C-ADS Injector I have been introduced and some preliminary results have been shown., Proceedings of the 4th International Beam Instrumentation Conference, IBIC2015, Melbourne, Australia

The China Accelerator Driven Subcritical system (C-ADS) linac, which is composed of an ECR ion source, a low energy beam transport line (LEBT), a radio frequency quadrupole accelerator (RFQ), a medium energy beam transport line (MEBT) and cryomodules with SRF cavities to boost the energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam phase as well as beam current and beam losses. Though many are conventional design, They can provide efficient operation of drive linac. This paper gives an overview and detail in beam commissioning of C-ADS linac beam instrumentation., Proceedings of the 57th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams, HB2016, Malmö, Sweden

Electron Cloud Instability has been studied in the operation of BEPC. The BEPC II began the commissioning in November 2006 and the positron beam current has reached 500 mA. Because of such a high beam current, some instabilities such as ECI, bunch lengthening et al, have appeared during the operation. The experimental investigation on ECI during the commissioning of BEPC II will be reported in this paper.

The driver linac of the China Accelerator Driven Subcritical system (C-ADS), which is composed of an ECR ion source, a low energy beam transport line (LEBT), a radio frequency quadrupole accelerator (RFQ), a medium energy beam transport line (MEBT) and cryomodules with SRF cavities to boost the energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam phase as well as beam current and beam losses. Though many are conventional design, They can provide efficient operation of drive linac. This paper gives an overview of C-ADS linac beam instrumentation., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

R&D project has been initiated for a proposed ultralow emittance (~50pm.rad) synchrotron light source built in Beijing. The R&D includes the development of high repetition rate laser pump/X-ray probe for ultrafast dynamics detection in future source. In a typical laser pump/X-ray probe measurement, the X-ray pulse follows a laser pulse in adjustable delay. We are interested in the difference between laser on and laser off at different delay, which will snapshot dynamic process. To capture this trivial difference, it requires the acquisition system to single out the signal from this special X-ray pulse at adequate S/N ratio. For the R&D of high repetition rate pump-probe, we have set up a prototype counting acquisition system based on NIM modular electronics, which was tested in Beijing Synchrotron Radiation Facility (BSRF). The laser will be synchronized with a camshaft bunch at 124 kHz, a tenth of the revolution frequency. Avalanche Photo Diode (APD) was used to detect the X-ray pulse from this camshaft bunch due to its nanosecond response. Before the laser is delivered, we mimic the 124 kHz laser- on signal. The signals from APD are separated by power dividers into two Constant Fraction Discriminator (CFD) input channels. The signal in laser-on/off channel is gated out at 1.24MHz using the 1.24MHz timing signal divided from 499.8 MHz RF signal, while the mimic laser-on signal gated out at 124 kHz. Multiplied by ten times, the mimic laser-on signal counts should be consistent with the laser-on+off counts, if our counting modular works well. We carried out this test at 1W1B wiggler beam line to measure the Fe fluorescence signal. The performance of our system is demonstrated in the good consistency between mimic laser on and laser on+off signals., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA

Two non-invasive beam profile measurement methods were developed for China high intensity proton beams projects, including CSNS and ADS. The first consists in an IPM (ionization beam profile monitor) system which detect the ionized products from a collision of the beam particle with residual gas atoms or molecules present in the vacuum pipe. The second is an electron beam scanner which using a low energy electron beam instead of a metal wire to sweep through the beam. The deflection of electron beam by the collective field of the high intensity beam is measured. The charge density in the high intensity beam can be restored under certain conditions or estimated by various mathematical techniques. Here we present the design parameters of the IPM system, the signal intensity of ionization products, optimization of the electric field, machine designs of electrode, tracking of the ionization products and so on. The principle of the electron beam scanner and the test results which is based on a commercial electron gun from Kimball Physics are also introduced in details., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

A new bunch-by-bunch beam position measurement prototype system has been designed and built to monitor and analysis beam trip in the BEPCⅡ(Beijing Electron-Positron ColliderⅡ) machine. The fast ADC and programmable FPGA can obtain the beam information bunch-by-bunch, so we can analyze base on both time domain and frequency domain. In this paper we will presentation the system architecture and discuss some beam trip analysis result, such as beam instability, tune drifting, RF breakdown, and so on., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

BEPCII has two rings each with an injection system. The injection system of each ring consists of two kicker magnets and a septum magnet. The injection layout of two rings is the same. Both two kickers would kick the beam in horizontal plane. The betatron phase advance in the horizontal plane between two kickers is designed exactly 180° in order to reduce the perturbation to the circulating beams during injection. In fact, the residual orbit oscillation will originate because of the existence of a variety of errors. The Librea Electron BPM processor is used to acquire the beam position data in turn-by-turn mode and to analyze the residual orbit oscillation. According to the measurement results, minimization of the residual orbit oscillation can be done by adjusting the peak field strength and trigger timing delay of two kickers. With very small residual orbit oscillation the two beams can keep collision condition during the injection.