Diagnostic Method for Beam Position Monitor Based on Clustering by Fast Search and Find of Density Peaks

Beam position monitors(BPMs)are important to monitor the beam moving steadily.Keeping the beam's normal motion is an important mission for Shanghai Synchrotron Radiation Facility.Effective diagnostic analysis is an important way to accomplish this task.This paper develops a new method based on clustering analysis to diagnose the healthy of BPMs with basic running data,i.e.,the β oscillation of X and Y directions and noise data.The analysis results showed that all beam position monitors(140 BPMs)can be classified into three groups:normal group,worse performance group,and fault group,respectively.In addition,the abnormal BPMs(including worse performance)could be marked.The new method showed its ability to handle faulty BPMs and it could instruct daily maintenance.On the other hand,it will be a useful supplement for data analysis in accelerator physics.

Electro-mechanical offset measurements of beam position monitors

Purpose The absolute beam position measurement in the booster and storage ring of the high energy photon source(HEPS)requires the offset between the electrical and mechanical centers of the beam position monitor(BPM).Method Traditionally,an RF signal is sent to an antenna or stretched wire aligned with the vacuum chamber,and the signal at each electrode is measured.Conversely,a replacement method using a vector network analyzer,which was proposed by Lambertson,does not involve mechanical alignment and can be used for electrical offset determination.Results and conclusions The electro-mechanical offsets of booster BPMs of the HEPS were measured using the Lambertson method.The result shows good agreement with the stretched wire method within a 30μm error.

Design and simulation of a wire position monitor for cryogenic systems in an ADS linac

This paper introduces the design and simulation of a Wire Position Monitor （WPM） used in the cryogenic system of an Accelerator Driven System （ADS）. The WPM is designed to monitor the contraction of cold masses during the cooling-down operation. In this paper, POISSON-2D electrostatic field software is used to calculate the best characteristic impedance for the WPM. Furthermore, the time domain signal of different end structures is theoretically analyzed and simulated. The coupling of electrodes and the influence of signal carrier size, which may influence the induced signal, are also discussed. Finally, the linearity of the induced voltage and the sensitivity of the WPM are analyzed. The time domain simulation results are consistent with the theoretical analysis. The influences of the coupling and carrier size are very small, and the linearity of the normalized voltage is good within r/2.

Capacitive beam position monitors for the low-β beam of the Chinese ADS proton linac

Beam Position Monitors（BPMs） for the low-β beam of the Chinese Accelerator Driven Subcritical system（CADS） Proton linac are of the capacitive pick-up type.They provide higher output signals than that of the inductive type.This paper will describe the design and tests of the capacitive BPM system for the low-β proton linac,including the pick-ups,the test bench and the read-out electronics.The tests done with an actual proton beam show a good agreement between the measurements and the simulations in the time domain.

Design and simulation of a beam position monitor for the high current proton linac

In this paper, the 2-D electrostatic field software, POISSON, is used to calculate the characteristic impedance of a BPM （beam position monitor） for a high current proton linac. Furthermore, the time-domain 3-D module of MAFIA with a beam microbunch at a varying offset from the axis is used to compute the induced voltage on the electrodes as a function of time. Finally, the effect of low β beams on the induced voltage, the sensitivity and the signal dynamic range of the BPM are discussed.

A new measurement method for electrode gain in an orthogonally symmetric beam position monitor

The new beam position monitor（BPM） system of the injector at the upgrade project of the Hefei Light Source（HLS II） has 19 stripline beam position monitors. Most consist of four orthogonally symmetric stripline electrodes. Differences in electronic gain and mismachining tolerance can cause changes in the beam response of the BPM electrodes. This variation will couple the two measured horizontal positions, resulting in measuring error. To alleviate this effect, a new technique to measure the relative response of the four electrodes has been developed. It is independent of the beam charge, and the related coefficient can be calculated theoretically. The effect of electrode coupling on this technique is analyzed. The calibration data is used to fit the gain for all 19 injector beam position monitors. The results show the standard deviation of the distribution of measured gains is about 5%.

Automatic test system development for digital beam position monitor of HEPS and BEPCII

Purpose Hundreds of digital beam position monitor processors(DBPM)are required to be produced during the construction of projects such as High Energy Photon Source(HEPS)and the upgrade project of the Beijing Electron Positron Collider(BEPCII),which brings great challenges to the test work.In order to achieve accurate,fast,and complete mass production tests of DBPMs,an automatic test system(ATS)has been developed in this article.Methods According to the test items of DBPM,the standardized testing softwareflow is designed based on virtual instru-ment program control technology and experimental physics and industrial control system(EPICS),which realize automatic adjustment of test parameters and automatic acquisition of test result data.Results and conclusions The ATS can realize one-button testing of channel coefficients,channel linearity,attenuator linearity,beam current dependence(BCD)and sampling signal-to-noise ratio(SNR),and generate test reports.The total test time is less than 3 minutes,which is significantly more efficient compared to manual testing.More than 90 BEPCII DBPMs has been tested by this ATS in the lab.The test results proved that such a system could automatically recognize defective products and satisfy the requirements of mass testing.

Application of Lightning Monitoring and Positioning Data in Investigation and Identification of Lightning Disaster in Inner Mongolia

The lightning current magnitude and other characteristics are important basic data of the lightning disaster investigation and identification. The characteristics of lightning monitoring and positioning system in Inner Mongolia were introduced and studied in the lightning accident analysis based on the lightning monitoring and positioning data of the lightning stroke accidents. The positioning error of lightning monitoring and positioning system was analyzed. The results showed that lightning current intensity and the position precision were very important data in the lightning disaster investigation. Finally, a variety of meteorological data should be applied in the lightning disaster investigation and identification.

基于超声波传感技术的气泄漏在线监测智能阀门定位器的设计

提出了基于超声波传感技术的阀门填料函处气体泄漏在线监测方法。利用传感器识别气体泄漏产生的气泡并输出低电平的原理,创新性的将超声波传感器与传统的智能阀门定位器控制功能进行了集成,实现对阀门填料气泄漏的实时在线监测,确保阀门安全、稳定运行,最大程度降低阀门泄漏监测成本,也填补了我国在阀门外泄露在线监测领域的一大技术空白,为石油、化工、电力等领域气体泄漏防治提供了解决方案。

Land deformation monitoring in mining area with PPP-AR

The mining area deformation monitoring theory and method using precise point positioning （PPP） ambi- guity resolution （AR） were studied, and an ambiguity fixing model with satellite and receiver combina- tion phase delay （CPD） was proposed for zero-differenced PPP ambiguity fixing and its corresponding formula derivation was given. The data processing results for I h at six IGS stations in China show that 93% of ambiguities can be fixed within 10 min and all ambiguities can be fixed within 15 min. After ambi- guity fixing, the positioning accuracy is improved by more than 85% in the E and N directions, with abso- lute positioning accuracy reaching millimeter level, and it was improved by 70% in the U direction, reaching centimeter level; the proposed zero-differenced ambiguity fixing model can effectively improve the convergence rate and positioning accuracy in PPP. Data monitoring continuously conducted for half a year at four COPS stations of Shanxi China Coal Pingshuo Group validated the feasibility of using PPP in mining area deformation monitoring.

Hydraulic Installation for Water Aeration

This paper presents some problems related to water quality and the condition of lakes in Romania, as well as methods for improving the quantity of oxygen dissolved in water. A method for water aeration and the installation used to implement it are described and the associated advantages regarding the reduction in the level of eutrophication are highlighted. The hydraulic installation for improving the quality of water from lakes, basins, reservoirs or slow flowing rivers was designed and tested in our hydraulics laboratory during a research project. It is floatable, environmentally friendly, and energetically autonomous, being powered by photovoltaic panels, which together with rechargeable batteries can assure a continuous operation. This installation could also be used in early stages of wastewater treatment. Experimental results regarding the performance curves of the hydraulic installation are also presented.

A nonradiographic strategy to real-time monitor the position of three-dimensional-printed medical orthopedic implants by embedding superparamagnetic Fe_(3)O_(4) particles

Monitoring the position of orthopedic implants in vivo is paramount for enhancing postoperative rehabilitation.Traditional radiographic methods,although effective,pose inconveniences to patients in terms of specialized equipment requirements and delays in rehabilitation adjustment.Here,a nonradiographic design concept for real-time and precisely monitoring the position of in vivo orthopedic implants is presented.The monitoring system encompasses an external magnetic field,a three-dimensional(3D)-printed superparamagnetic intervertebral body fusion cage(SIBFC),and a magnetometer.The SIBFC with a polyetheretherketone framework and a superparamagnetic Fe_(3)O_(4) component was integrally fabricated by the high-temperature selective laser sintering technology.Owing to the superparamagnetic component,the minor migration of SIBFC within the spine would cause the distribution change of the magnetic induction intensities,which can be monitored in real-time by the magnetometer no matter in the static states or dynamic bending motions.Besides horizontal migration,occurrences of intervertebral subsidence in the vertical plane of the vertebrae can also be effectively distinguished based on the obtained characteristic variations of magnetic induction intensities.This strategy exemplifies the potential of superparamagnetic Fe_(3)O_(4) particles in equipping 3D-printed orthopedic implants with wireless monitoring capabilities,holding promise for aiding patients'rehabilitation.

Effect of Laser Welding on Properties of Dissimilar Joint of Al-Mg-Si and Al-Mn Aluminum Alloys

This study discusses the welding properties for the components of an aluminum-alloy ultra-high vacuum chamber and beam position monitor （BPM）.The welding parameters include the modes of laser output （pulsed wave and continuous wave）,welding speed,shield gas flow,welding bead structure,and focusing distance.The results showed that the welding defect rate of the pulsed wave type was larger than that of the continuous wave type.The crack in the welding bead reduced with decreasing welding speed.The fusion penetration of the welding bead was higher when the focusing distance was long enough to deepen into the welding material.Weld morphology during the experimental process revealed the proper flow of shield gas.The adaptability design of the welding bead structure in the preceding processes had more effect on overall welding structure and morphology.

Conditioning of BPM pickup signals for operations of the Duke storage ring with a wide range of single-bunch current

The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers（FELs）, and the High Intensity Gamma-ray Source（HIGS）. It is operated with a beam current ranging from about1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and γ-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors（BPMs） are required to be able to precisely measure the electron beam orbit in a wide range of the single-bunch current. However, the high peak voltage of the BPM pickups associated with high single-bunch current degrades the performance of the BPM electronics, and can potentially damage the BPM electronics. A signal conditioning method using low pass filters is developed to reduce the peak voltage to protect the BPM electronics, and to make the BPMs capable of working with a wide range of single-bunch current. Simulations and electron beam based tests are performed. The results show that the Duke storage ring BPM system is capable of providing precise orbit measurements to ensure highly stable FEL and HIGS operations.

Preliminary application of turn-by-turn data analysis to the SSRF storage ring

There is growing interest in utilizing the beam position monitor turn-by-turn（TBT） data to debug accelerators. TBT data can be used to determine the linear optics,coupled optics and nonlinear behaviors of the storage ring lattice. This is not only a useful complement to other methods of determining the linear optics such as LOCO,but also provides a possibility to uncover more hidden phenomena. In this paper,a preliminary application of a β function measurement to the SSRF storage ring is presented.

Design and simulation of cavity BPM for BEPCII

Background In the linac of Beijing Electron Positron Collider II(BEPCII),the resolution of existing BPMs is several hundred microns.But the requirement of transverse position resolution of BPM for future top-up injection needs to be more precise.Purpose This paper is mainly concerned about the design and simulation of the cavity beam position monitor(CBPM)for BEPCII linac and free electron laser(FEL).The requirement of beam transverse position resolution for linac is several microns,even a few nanometers for FEL.Methods When the beam bunch goes through the CBPM,it can excite different electromagnetic field modes in resonator.In these modes,TM_(110) is the most sensitive to beam transverse position offset.The design of CBPM is aim to analyze the relationship between TM_(110) and beam transverse position by CST Studio and Ansys HFSS.Conclusion In this research,we design a pair of rectangular slots for position cavity to revise the direction of electromagnetic field.The simulation result of theoretical resolution is able to reach 15 nm@1nC with the operating frequency 2500 MHz.It is obviously that CBPM has more excellent resolution than all of operating BPM in BEPCII.Meanwhile,the research of CBPM improves the application of beam detection technology in BEPCII and accumulates technology for future design of HEPS and FEL.The mechanical design of the prototype is being fabricated.