The accurate measurement of the transverse position of a beam is crucial in particle accelerators, as it plays a key role in determining the beam parameters. Existing methods for beam position measurement rely on the detection of image currents induced on electrodes or the narrow-band wake field excited by the beam passing through a cavity-type structure. These methods have some limitations. Indirectly measuring the multiple pa rameters is computationally complex and requires external calibration to determine the system parameters in advance, and the utilization of the beam signal information is incomplete. In this work, a novel method that measures the absolute electron beam transverse positionis proposed. By utilizing the geometric relationship between the center position of the measured electron beam and multiple detection electrodes, as well as analyzing the differences in the arrival times of the beam signals detected by these electrodes, the absolute transverse position of the electron beam crossing the electrode plane can be calculated. This method has features such as absolute position measurement, position sensitivity coefficient independent of the vacuum chamber aperture, and no requirement for symmetrical detector electrode layout. The feasibility of this method is validated through numerical simulation and beam experiments.

The Shanghai high repetition rate XFEL and extreme light facility (SHINE) under construction is designed as one of the most advanced FEL facilities in the world, which will produce coherent x-rays with wavelengths from 0.05 to 3 nm and maximum repetition rate of 1MHz. To achieve precise beam trajectory measurement and stable alignment of the electron and photo beams in the undulator, the cavity beam position monitors (CBPM) including beam diameters of 35mm in LINAC and Bunch distribution section and 8mm in undulator have been designed and developed for the SHINE. The requirement of the transverse position resolution is better than 1μm and 200 nm for a single bunch of 100 pC, respectively. In this paper, we present the design of the cavity BPM system and the processing of the key equipment. The beam test bench has been established at the Shanghai Soft X-ray FEL facility (SXFEL), and preliminary beam experiments indicate that, with the bunch charge about 100pC, the position resolution of CBPM-35mm and CBPM-8mm is better than 330 nm and 70 nm, respectively.

The construction of China Accelerator Facility for Superheavy Elements(CAFe2) is advancing based on Chinese ADS Front-end Demo Linac(CAFe). However, the original Beam Position Monitor(BPM) read-out electronics of CAFe could not meet the requirements of the CAFe2 BPM probes in terms of quantity and the measurement demands of low-intensity heavy ion beams. In response to this challenge, a high-speed RF switch array supporting multi-channel multiplexing, adjustable gain and filtering was developed. This array served as the RF signal conditioning front-end, together with the RF front-end and digital signal processing platform, to constitute a complete BPM read-out electronics. Laboratory testing validated the feasibility of the high-speed RF switch array and the entire read-out electronics. Compared with traditional read-out electronics, the read-out electronics equipped with the high-speed RF switch array enables the measurement of 32 signals from 8 BPM probes. This approach significantly improves the system's integration and reusability, while offers an efficient solution for implementing multi-channel time-division multiplexing measurement under different beam intensities and operating frequencies. Additionally, by simultaneously accessing signals from multiple BPM probes, this system better supports differential measurement. Overall, the high-speed RF switch array not only meets the requirements of CAFe2 but is also applicable for other accelerators with multiple BPM probes.

The Iranian Light Source Facility Storage Ring is under design with a 528 m circumference and will store the electron bunches with 3 GeV energy to produce high-flux radiation that ranges from infrared to hard X-rays. Two Striplines are planned to be installed in the ILSF storage ring for beam tune measurement. The first one will be used for exciting the beam and the other for horizontal and vertical beam position measurements. In this paper, the design of the striplines for the ILSF storage ring is investigated. Each stripline is matched with 50Ω and has 4 strips (electrodes) that are placed at 45 degrees to the beam axis, the best geometry is achieved and optimized by CST Microwave Studio simulation.

The Iranian Light Source Facility Booster is under design with a 504 m circumference and will accelerate the electron bunches from 150 MeV to 3 GeV. the 50 button-type beam position monitors (BPMs) are considered the non-destructive tools to measure the beam position in the ILSF booster. In this paper, the design of the BPM for the ILSF booster is studied. The BPM blocks have 4 buttons (electrodes) that are placed at 45 degrees to the beam axis. to choose the best geometry, The BPMs with different button diameters and gaps are simulated by the CST Microwave Studio and BpmLab.

This paper presents a prototype of BPM electronics for experimental installation of free electron laser and high magnetic field (FEL-HMF). FEL-HMF integrates mid-long Infrared free electron laser, high magnetic field and cryogenic, which is a critical apparatus for new advanced materials especially for low-power electronic materials. The BPM electronics consists of two ADC chips and one FPGA SoC. The ADC has two channels, and sampling rate is 240Msps. The FPGA SoC implements high speed digital signal and data process. The logic part of FPGA SoC is running signal process. The processor part of FPGA SoC runs Linux operating system and EPICS-based user application program. This BPM electrons has been tested and analyzed in lab. Its X and Y position is ~1.4um (RMS).

Hefei Advanced Light Facility (HALF) is a fourth-generation vacuum ultraviolet and X-ray diffraction limit synchrotron radiation (DLSR) light source under construction. It is expected to have an ultra-low emittance and an extremely small beam size, which requires high-precision orbit detection and fast feedback control. The processor is the key component of the digital beam position monitor (DBPM) and control system, which is required to provide a submicrometer resolution in beam position measurement with a processing latency of lower than 90 μs. This paper presents the design and testing of a high-precision low-latency DBPM processor. In order to reduce the latency and ensure the high position resolution, a specific higher sampling frequency is chosen to reduce the quantization noise platform of the analog to digital convertor and an optimized low-order filter is adopted. Specialized efforts are devoted to the low jitter sampling clock generation and low noise analog circuit design. Furthermore, a dual-pilot tone structure was employed to compensate the gain variations across the four channels of the beam monitor sensor. The laboratory test results show that the DBPM has a position resolution of better than 400 nm for turn-by-turn acquisition, better than 90 nm for fast acquisition at 20 kHz rate, and better than 20 nm for slow acquisition at 10 Hz rate, with a total latency of less than 80 μs.

At the High Energy Photon Source (HEPS), a high orbital stability of typically 10 % of the beam size and angular divergence must be achieved, which implies that the beam orbit must be stabilized to the sub-micrometer level. A button and stripline beam position monitor (BPM) were designed based on the analytical formulas and CST simulations results. The results of electromagnetic field simulations revealed how various mechanical errors, such as button size and location accuracy, as well as the related button capacitance, exert different influences on the beam position measurement. The performance of an actual BPM pickup was measured, along with an assessment of the error on the beam position measurement. Additionally, a wakefield analysis, including an investigation of trapped resonant modes and related thermal deformation, was conducted. The characteristic impedances of the stripline were designed to be 50 Ω and confirmed by measurements. The position sensitivity, position resolution, capacitance and the electro-mechanical offsets were measured using the Lambertson method, and the calibration coefficients were measured using a stretched wire.Various problems that arise during the processing and installation process will also be introduced.

The injection kicker design exploiting strip-lines and linear taper connections of the strip-lines to the feedthroughs was proposed and has been successfully used in the DAFNE electron-positron collider [1]. Such a design has helped to reduce the device beam coupling impedance, to improve the uniformity of the deflecting electromagnetic fields and to provide better matching with the feedthroughs. In this paper we propose using nonlinear taper connections in order to decrease further the beam coupling impedance. We have performed numerical simulations and analytical studies of several nonlinear tapers demonstrating that the coupling impedance can be substantially reduced while keeping or even improving the transfer (signal) impedance of the strip-line kickers (or BPM). The effect of the nonlinear tapering is particularly important for short strip-line devices when the taper length is limited due to lack of available space and/or when the strip-lines are moved closer to the beam in order to increase the device shunt (signal) impedance.

Wuhan Photon Source (WHPS), as a fourth-generation synchronous light source, imposes stringent requirements on the resolution and longitudinal coupling impedance of the Beam Position Monitor (BPM). To address the need for beam current monitoring in its 1.5 GeV diffraction-limited storage ring, an optimized design scheme for button BPM is proposed. Additionally, the structure of the BPM feedthrough is enhanced, and a detailed investiga-tion into the impact of various materials on the longitudi-nal coupling impedance of the BPM is conducted. These findings serve as a valuable reference for the future de-sign of similar BPM systems.

RF direct sampling and processing of beam signals has always been the goal pursued in beam diagnostic systems. Now it’s time to make it happen. For the first time, a high-sensitivity RF direct sampling processor has been developed for C-band cavity pickups in SHINE/SXFEL. It redefines the beam diagnostic system. There is no longer a need for complex analog down-conversion modules in traditional cavity BPM/BAM systems. In addition, the processor can simultaneously meet the signal processing needs of different cavities with a center frequency below 6 GHz. Obviously, the RF direct sampling processor greatly reduces the complexity and costs of the system, shows great versatility. Meanwhile, compared to the down-conversion electronics, this processor demonstrates much higher sensitivity (twice) due to a significant reduction in analog components. The processor also has a huge advantage in other beam diagnostics because of its wide bandwidth and high sampling rate, such as bunch-by-bunch measurement and feedback system on synchrotron radiation facility. Now it's time to massively apply the RF direct sampling processor to promote the development of beam diagnostic technology.

The beam position monitor (BPM) is a crucial instrumentation system for the commissioning and operation of the accelerator. Its accuracy and robustness are essential for ensuring the stability of the accelerator. Currently, the beam position is calculated by fitting a polynomial to the four voltage signals obtained from the BPM electrodes in BEPCII and HEPS. To improve the system’s robustness, a formula is provided that expresses the relationship between the three voltage signals and the position. The average fitting error is 40 𝜇m, but the error of the three-electrode calculation is not high. Therefore, we propose using neural networks for beam position calculation to improve the system’s robustness while guaranteeing its accuracy. This will ensure that the beam position can be provided stably, even in the case of one single electrode error. In our experiments, we use BPM calibration data from HEPS. The trained neural network’s performance on the test set meets the accuracy requirements, with an error of less than 15 𝜇m in both four-electrode and three-electrode predictions, and an average value of fitting error is 1 𝜇m. Furthermore, we validate the neural network’s generalization ability by using data measured by BPM on HEPS.

We are developing a BPM system for the 6 GeV fourth-generation light source, SPring-8-II, which is a renewal of the third-generation light source, SPring-8. The new storage ring will be equipped with 340 button-type BPMs. BPM heads with molybdenum button electrodes have been designed to achieve the position sensitivity coefficients required for SPring-8-II as well as minimal beam impedance and heat dissipation. The BPM heads for the vacuum chambers of the prototype cell are currently being fabricated to validate the mechanical design. As for radiation-resistant signal cables, PEEK-insulated semi-rigid cables will be used for connection to the BPM head, and polyethylene-insulated corrugated cables relay from the girder side to the readout electronics. High-precision and stable readout electronics consist of RF front-end boards and high-speed digitizer boards based on the MTCA.4 standard. The initial batch of electronics has already been installed to replace the obsolete single-pass BPM system of the current SPring-8, and the performance evaluation is in progress. In this presentation, we will report the overview and the development status of the SPring-8-II BPM system.

The Cavity Beam Position Monitor (CBPM) system at Accelerator Test Facil- ity 2 (ATF2, KEK, Japan) operates with attenuation at a reduced 200 nm (vs measured 20-30 nm) resolution to cope with CBPM to magnet misalignment. In addition, CBPMs need regular calibrations to maintain their performance. To address these limitations, a pulse injection system is under development. This system aims to compensate for static offsets by injecting an anti-phase replica of the average beam signal directly into the sensor cavities. The same signal can provide a calibration tone for the whole processing chain and eliminate lengthy beam-based calibrations. Proof of principle tests for such a system have been conducted in December 2023. In this paper, we report on the results of the first beam test, discuss the technical challenges and provide a preliminary hardware specification for future experiments.

The CSNS accelerator complex is upgrading the injection area to improve the beam-loss control during beam injection and acceleration in the Rapid Cycling Synchrotron. At CSNS, the linac beam energy will be increased from 80MeV to 300MeV employing a new superconducting accelerating section, and the beam power at the spallation target will be 500kW. To accomplish these requirements, a stripline-type BPM has been designed with a large aperture and 50 Ω stripline electrodes. This BPM has an inner diameter of 52 mm and is used to detect the beam with a current of 10-30 mA and a pulse width of 100-500us. Several geometrical and electrical parameters have been optimized with numerical simulation. This paper will describe the design and optimization of the stripline-type BPM in detail, and simulation results are discussed.

Feedthroughs have been used for different accelerator detectors, such as BPM, BAM, CBPM, ACCT, and the RF cavities etc. that are used to test the beam properties and RF cavity signals. For this purpose, large bandwidth with low transfer loss is required. The long-life and high-stability are also needed. The SMA-type and N-type feedthroughs are developed. The bandwidth of the SMA-type is up to 20 GHz, and that of the N-type up to 13 GHz with low transfer loss. Those feedthroughs have used in the strip-BPM, button-BPM, and CBPM etc..

The High Intensity Proton Accelerator (HIPA) at PSI presently has an RF beam position monitor (BPM) system based on 20 year old Xilinx Virtex-2 Pro Systems-on-Chip (SoC), using application-specific integrated circuits (ASICS) for direct digital downconverters. For the planned upgrade of the electronics as well as for new HIPA projects, we started the development of a new HIPA BPM electronics, using a generic electronics platform called "DBPM3" that is already being used for SwissFEL and SLS 2.0 electron BPM systems. In this contribution, first test results of a DBPM3-based HIPA BPM electronics prototype are presented, including a comparison with the present electronics.

The AWAKE facility uses novel proton beam-driven plasma wakefields to accelerate electron bunches over 10m of Rubidium plasma. Precise monitoring of 2 diverse beam types necessitates an electron beam position monitor (BPM) working in a frequency regime of tens of GHz. A high frequency conical button-style BPM with a working regime of up to 40 GHz has been investigated as a way to discriminate the electromagnetic fields of 19 MeV, 4 ps electron bunches propagating spatially and temporally together with a 400 GeV, 170 ps proton bunch in the AWAKE common beamline. The sensitivity of the HF BPM to the electron beam position is determined under various beam conditions, with both electrons and protons, and integration with a TRIUMF front-end is discussed.

The on-line calibration of beam synchronous phase (SP) is crucial for enhancing the operational efficiency of accelerators. Recently, we developed an artificial intelligence (AI)-based beam information measure model that uses transient beam loading information as input while simultaneously predicting beam current and SP. This method employs Long Short-Term Memory (LSTM) to extract multi-dimensional radio frequency (RF) time-series features and incorporates an attention mechanism to evaluate the weights of RF waveforms at different times. The method can work in complex operating conditions such as open-loop, closed-loop, and with or without cavity detuning, and has higher precision and stronger generalization capabilities compared to other online calibration method of SP (such as those based on cavity differential equations or RF beam vector). We validated the consistency of the algorithm results with BPM and BCM measurements on the Buncher of European Spallation Source. Our method achieves an mean absolute error of 0.28° for predicting SP and 0.47 mA for predicting beam current, showing very promising results.

Beam position monitor(BPM) is used to measure the horizontal and vertical positions of the beam in the vacuum pip.　Before online installation,　it usually needs to be calibration.　High Intensity Heavy-ion Accelerator Facility(HIAF) and China initiative Accelerator Driven System(CiADS) will need a large number of BPM,　so it is a great challenge for BPM calibration work. In order to complete this work efficiently and accurately,　this research designs and develops an automatic BPM calibration system. The hardware of this BPM calibration system consists of 4 major sections,　they are calibration platform equipment, precise motion control device,　signal processing electronics and industrial computer. The control software was programmed by C to realize automatic calibration functions based on EPICS. A high-order fitting algorithm programmed by python used to solve the problem of smaller linear range of the capacitive BPM. It significantly improves the accuracy of position measurement after calibration.

High Energy Photon Source (HEPS) is a proposed new generation light source with a beam energy of 6 GeV, high brightness, and ultra-low beam emittance. An RF BPM has been designed at IHEP as part of an R&D program to meet the requirements of both the injection system and storage ring. The RF BPM architecture consists of an Analog Front-End (AFE) board and a Digital Front-End board (DFE) based on a custom platform. In this paper, we present the overall architecture of the RF BPM electronics system and the performance evaluation of the BPM processor, including beam current, filling pattern, and position measurement resolution as a function of the beam current.

As part of the CSNS-II upgrade, the H- LINAC beam energy will be increased from 80 MeV to 300 MeV using superconducting cavities. To accurately measure beam position, phase, and energy, stripline-type Beam Position Monitors (BPM) are essential. The shorted-type stripline BPM was chosen for this upgrade due to its excellent S/N ratio and rigid structure. As space is limited in the LINAC's SC section, the BPMs must be embedded in the quadrupole magnet. Two prototypes, with inner diameters of 50 mm and 96 mm, were designed using numerical simulation codes and manufactured for beam testing. This paper will detail the simulation, design, and beam test results of the prototype BPMs for CSNS-II.

The first phase of the China Spallation Neutron Source (CSNS) project aims to accelerate negative hydrogen ions to 80 MeV using a linear accelerator. Subsequently, these negative hydrogen ions are converted into protons after stripping, and then injected into a rapid cycling proton synchrotron. The proton beam is further accelerated to an energy of 1.6 GeV and guided through a beam transport line to a tungsten target, where spallation reactions gen-erate neutrons. With the initiation of the Phase II project of the China Spallation Neutron Source (CSNS II), the target power is anticipated to increase significantly to 500 kW in the future. Upgrading the existing 32 sets of BPM electronics on the Rapid Cycling Synchrotron (RCS) ring is essential to accommodate the enhanced beam power and fulfill the new requirements of the beam measurement. This paper focuses on the novel design and validation of the BPM electronics, as well as the execu-tion of tests during beam operation.

A BPM signal processor has been developed for SSRF since 2009. It composed of Virtex5 FPGA, ARM board, and 4 125MSPS sampling rate ADCs. Since then, electronic technology has made significant progress. Such as Zynq UltraScale+ MPSoC FPGA contains both hard-core ARM and high-performance FPGA, and ADCs with a sampling rate of 1GSPS have been applied in mass production. A new BPM processor with Zynq UltraScale+ MPSoC FPGA and 1GSPS ADCs is under development at SSRF. Due to the application of new technologies, the processor performance will be significantly improved. The new processor can also meet the needs of ultra-low emittance measurement for the new generation of light sources. This paper will introduce the design of the processor and the relative tests.

The machine protection system guarantees the safe operation of the HIAF (High Intensity heavy-ion Accelerator Facility) in different operating modes and also prevents damage to the online equipment in the event of a failure. Beam current data such as beam current position and phase is an important basis for analysing and diagnosing accelerator faults. In this paper, the authors designed the beam position and phase interlock monitoring system. The system is based on circular buffer and AXI4 protocol to realize the interaction of interlock data and locking of interlock status. At the same time, the system uses memory mapping to save the interlock beam data. Laboratory tests show that the system could save the beam position, beam phase, SUM signals and amplitude of sensed signal per probe path during interlocking before and after 8ms and latch the interlock status of 25 channels. The system was deployed at the CAFe-LINAC gas pedal in March 2024 to complete online measurements.

This study conducted offline calibration tests on the stripline Beam Position Monitor (BPM) designed for the Hefei Advanced Light Facility (HALF) injector. The Lambertson method was used to measure the off-set between the electrical center and the mechanical center of the BPM, with results showing horizontal and vertical offsets of 0.1154 mm and 0.1661 mm, respec-tively. Additionally, the wire-scan method was em-ployed to construct the BPM mapping, and polynomial fitting was applied to effectively reduce the BPM’s nonlinearity and system errors. The experimental re-sults provide essential data support for the optimiza-tion and practical application of the BPM in the HALF injector.

The Korean 4GSR project is currently under construction in Ochang, South Korea, with the aim of achieving first beam commissioning in 2027. Designed to achieve an emittance approximately 100 times smaller than that of third-generation synchrotron radiation storage rings, the project requires the development of several high-precision beam diagnostic devices. In particular, the beam position monitor (BPM) is aimed at reducing longitudinal wake impedance to suppress heating and beam instability. For this purpose, two types of 4GSR BPM pick-up antennas have been developed. The first utilizes a SiO2 glass insulator, while the second is designed in a cone shape using Al2O3. The differences and advantages of the two designs are explained, and the performance obtained through actual beam tests will be described. This presentation will provide an overview of the current development status of the beam position monitor developed for the 4GSR project, including details on the approximate configuration of the 4GSR BPM system.

This paper presents the first experiences acquired with the new eBPM system based on pilot tone compensation, developed for Elettra 2.0. After the successful delivery of seven complete systems, belonging to a pre-series production within the signed partnership with Instrumentation Technologies, we started their integration in the current machine, in order to gain experience and develop all the functionalities required for the future commissioning of the new accelerator, scheduled for 2026. To do so, an entire section of Elettra storage ring has been equipped with the new systems: eight Libera Electron units have been replaced by eight Pilot Tone Front End (PTFE) and four digital platforms (DAQ10SX). Tests were carried out during dedicated machine shifts, focusing on integration with the new global orbit feedback at different data rates (10 kHz, 100 kHz and turn-by-turn), with and without pilot tone compensation. Nevertheless, triggered acquisitions were made in order to test first turn capability of the system. Another unit has been attached to a pair of spare pick-ups (low-gap BPMs), in order to continue the development of new features and to provide different types of data (raw ADC data, turn-by-turn calculated positions, etc.) for machine physics studies, even during user-dedicated shifts.

This paper will show beam position studies performed using a Cherenkov Diffraction Radiation (ChDR) based Beam Position Monitor (BPM) at Diamond Light Source (DLS). Displaying the characterisation of the BPM using the 3 GeV electron beam at DLS and comparing the effectiveness of this prototype to an existing Inductive Beam Position Monitor (IBPM) in use in the DLS Booster To Storage (BTS) transfer line. The functionality of the BPM is explored, utilising both wideband and narrowband ChDR emission with the application of filters to the ChDR detection system.

This article introduces the intermediate stage amplifier electronics for the HIAF Ring beam diagnostic system, it has intermediate stage amplifier, high-impedance preamplifier gain switching control, self-check, fiber communication, and enthernet communication functions. The intermediate stage amplifier has 4 channels, each channel has three gain states: 20dB, 0dB, -20dB, combining with preamplifier which has 2 gain states (30dB and 0 dB), 6 gain states can be got to make the signal magnitude input to BPM electronics falls in optimal range for ADC sampling as possible. According to simulation result, the maximum voltage of BPM induction signal could exceed 40V with 50Ω impedance, so a low reflection low-pass filter is placed before amplifier to avoid the devices damage and signal reflection, the filter bandwidth is 10MHz and it can attenuate the peak voltage by half at shortest beam signal while S11＜-25dB. Electronics integrates two 8-pole LEMO connectors as control outputs to control the preamplifier gain state. The self-check signal is generated by an active crystal oscillator, and injected into 4 channels by 4 drivers. Optoelectronic converter, electro-optic converter and ethernet module are integrated to achieve remote communication. All control logic and communication is realized by an Actel FPGA chip.

In this paper we are presenting the status of the partnership between Instrumentation Technologies and Elettra Sincrotrone Trieste for the realization of 200 BPM electronics for ELETTRA 2.0. Last year, 200 Pilot Tone Front-End (PTFE) units were successfully developed and produced. During the present year, 100 Digital Acquisition platforms, each one used to digitize and process the signals from two BPM pickups, are in production after the successful pre-series tests. Elettra Sincrotrone Trieste was more involved in concept design, prototype development, and firmware programming, while Instrumentation Technologies was focused on design for manufacturing, implemented rigorous testing procedures, and handled the production. During the project, it was also necessary to overcome a period of material shortages, particularly for the chips used in the digital part. Testing during the pre-series and series production phases ensured that each unit met the desired performance criteria necessary for stabilizing long-term measurement drifts in BPM systems. Additional units were produced to account for potential failures and performance variations, ensuring that all units delivered performed to specification.

MYRRHA (Multi-Purpose Hybrid Research Reactor for High-Tech Applications) aims to demonstrate the feasibility of high-level nuclear waste transmutation at industrial scale. MYRRHA Facility aims to accelerate 4 mA proton beam up to 600 MeV. Beam Position monitors are key elements in many accelerators. for instance, once BPMs are installed along a linear accelerator or a storage ring, they remain inaccessible for any validation of updated or rejuvenated electronics. this paper addresses this issue with the realisation of an electronic test bench simulating the outputs signals of BPM electrodes for a given beam energy, phase and position. the bench is realized for MYRRHA BPMs and it offers simulated beams with a position precision down to 50μm and phase precision down to 0.5° on a wide range.

MYRRHA (Multi-Purpose Hybrid Research Reactor for High-Tech Applications) aims to demonstrate the feasibility of high-level nuclear waste transmutation at industrial scale. MYRRHA Facility aims to accelerate 4 mA proton beam up to 600 MeV. The accurate tuning of LINAC is essential for the operation of MYRRHA and requires measurement of the beam transverse position and shape, the phase of the beam with respect to the radiofrequency voltage with the help of Beam Position Monitor (BPM) system. MYRRHA is divided in two phases, the first phase, called MINERVA, includes several sections allowing beam acceleration up to 100 MeV. the second phase includes a High Energy Beam Transport (HEBT) line up to 600MeV. A BPM prototype was realized for the HEBT line. This paper addresses the design, realization, and calibration of this BPMs and its associated electronics. The characterization of the beam shape is performed by means of a test bench allowing a position mapping with a resolution of 0.02 mm.

Beam Position Monitors (BPMs) are essential in parti-cle accelerators for the precise measurement of beam trajectories. Considering the inherent inaccuracies in manufacturing and assembly, rigorous offline calibration processes are essential to guarantee the precision of beam position measurements. The predominant calibration technique, specifically the wire test method, is tailored for relativistic beams and is inappropriate for low-β beams. This manuscript introduces an innovative ap-proach employing a helical slow-wave structure to emu-late the electromagnetic fields of low-energy beams, thus facilitating the calibration of BPMs for low-β scenarios. Employing a helix-based calibration platform, we con-ducted the calibration of the nonlinear response of BPMs at the Xi'an Proton Application Facility for a 7 MeV pro-ton beam, with results aligning with the simulation. This advancement expands the precision and range of beam position measurements, substantially enhancing the op-eration and optimization of particle accelerators.

Measuring the absolute position of the beam in the intensifier and storage ring of a high energy photon source (HEPS) requires measuring the offset between the electrical and mechanical centers of the beam position monitor (BPM). In the HEPS project, a four-electrode BPM is used, and the signals from each of the four electrodes of the BPM probe are led out by a cable. During the operation of the intensifier and storage ring, the influence of ambient temperature and humidity on the BPM cable and the difference between the four channels will directly lead to changes in the BPM measurement results. In this paper, vector network analyzer (VNA) is used to test the data of signal amplitude change of two BPM cables within ten hours when temperature and humidity change. The conclusion is that the influence of temperature on the signal is about 0.01 dB/℃, the influence of humidity on the signal is about 0.05 dB/10%, and the relative change between channels is about 5%.

The PETRA IV project is set to enhance the current PETRA III synchrotron into an ultra-low-emittance source. The reduced emittance will impose stringent requirements on machine stability and operation. In order to cope with these requirements, bunch-by-bunch information is required from most of the monitor systems. For precise monitoring of beam position and charge, the Libera Digit 500 instrument was tested as a readout electronics for BPMs at the existing machine PETRA III. This system features four channels with a 500 MHz sampling rate, synchronized with the accelerator's RF, enabling observation of beam properties with a bunch-by-bunch resolution, thus facilitating a more comprehensive understanding of beam behavior. This contribution provides an overview of the latest beam measurements at the single bunch level, allowing observation of beam oscillations and injection dynamics.

SOLEIL II is the low emittance upgrade project for Synchrotron SOLEIL, targeting an emittance of ~80 pm.rad. The new lattice includes 180 Beam Position Monitors (BPM). Due to the different constraints on the magnet yokes, beam stay clear and synchrotron radiation, 3 different types of BPM will be installed on the storage ring with inner diameter distributed between 16 and 24 mm. Electromagnetic and thermal simulations have been conducted to validate the designs. Manufacturing the feedthroughs is a challenge due to the conical shape of the button and the small (200 µm) thickness of the gap with the BPM body. Prototypes of the button have been made by two different manufacturers, and possibilities for improvement identified. These prototypes will test in the current machine to validate the simulation results. This paper presents the designs, summarizes the results of the simulations, and describes the metrology process and results of the two batches of feedthroughs.

Beam Position Monitors (BPM) are the non-destructive monitors used most frequently at nearly all linacs, cyclotrons, and synchrotrons. The most basic function of BPM is to provide the accurate position of the centre of mass of the beam for closed orbit feedback and other demands. However, due to the error of actual processing, the k value and the actual electric center will be different with the ideal k value and electric center of BPM, which requires us to accurately measure the k value and offset value of each set of BPM offline. There are 72 sets of BPMs in HIAF BRing & SRing, with 10 specifications and plate radius ranging from 180mm to 330mm, but the shape and size of the front and back pipes connected to bpms are variety during actual installation. Based on theoretical analysis, the k value and offset value of the BPM which electrode plates are too close to the flange are greatly affected by the pipes connected to bpm at both ends, and the measurement error can even reach 9mm. Therefore, this paper takes HIAF BRing and SRing BPM calibration as examples to explain how to accurately calibrate BPM.

Accurate monitoring and control of charged particle beams at the HL-LHC demands the development of new beam diagnostics tools. This poster provides an overview of the electro-optic beam position monitor (EO-BPM), currently taking measurements at CERN's SPS. This device uses the Pockels effect to monitor the transverse position and instabilities in the particle beam. Comprising of a laser source, electro-optic crystal, optical system, and a fast photodetector, the EO-BPM operates by generating a modulated optical signal directly linked to the propagating electric field of the beam. The EO-BPM is designed as a self containing button with fibre-coupled laser connected to the crystal inside and a fibre coupled Mach-Zehnder interferometer yielding sum and difference signals on the outside. A segment of the SPS beam pipe is fitted with a mount to connect the button, allowing the electric field induced by the particle beam to be captured and transferred to the electro-optic crystal. The goal is to gain insight into the transverse position along the bunch and the identification of intra-bunch instabilities, contributing to precision in beam monitoring and control.

This project aims to collect high-frequency high-precision data from the weak current signals generated by the quadrant-type diamond detector used for high-precision beam position monitoring. The main approach is to design a current conversion amplification circuit based on the theory of high-resistance I-V weak current to achieve fast conversion and collection of the four-channel weak current with large dynamic range and multiple ranges at high frequency, with the highest precision reaching the pA level. The circuit uses the ADA4530-1 amplifier with extremely low input bias current budget to complete the front-end circuit setup. The circuit's bandwidth is simulated and analyzed, with the bandwidth limited to 159 Hz. The design uses a protection ring design, a three-axis BNC connection, and a custom shielded box to enhance the shielding performance of the measurement system. The output signal is converted to a 24-bit high-precision analog-to-digital signal by the AD7172-2, and further connected to the core control board for signal closed-loop control to achieve overall isolation of the analog and digital circuits. The final experimental test shows that the detection sensitivity of the circuit for pA-level weak currents is 9.7936 mV/pA, and the error of the circuit is 1.3% when the weak current is greater than 10 pA, which can meet the demand for beam position measurement in the stable beam system.

Beam Position Monitor (BPM) system is an important part of the beam measurement system, which plays a vital role in the stable operation of the accelerator. In this paper, based on the requirement of high resolution of the BPM system, the DBPM algorithm is implemented on Matlab and FPGA, firstly, the overall design of the DBPM algorithm is introduced; secondly, the implementation method of each module is elaborated in detail; and again, the existing simulation data and the beam current data are simulated in the Matlab and Modelsim environments respectively, using the quadrature demodulation and Moving Average Filter; finally,do offline testing based on this DBPM algorithm Experimental. Results show that the quadrature demodulation algorithm incorporating a sliding average filter has higher positional resolution.

The Photo Injector Test Facility at DESY in Zeuthen (PITZ) has been developing high brightness electron sources for the XUV and soft X-ray free-electron facility (FLASH) and the European X-Ray Free Electron Laser facility (EuXFEL) at Hamburg. Its research fields have expanded into applications in recent years like THz FELs, and radiation biology for cancer treatment. Since the applications require varying beam parameters(bunch charge from <10 pC up to 4 nC, momentum from 6 MeV/c up to 22 MeV/c), a robust and reliable beam trajectory recovery and correction algorithm has been developed, which allows to fast establish and/or recover a quasi-optimal performance for different experiments. One of the key functions is to make certain quadrupoles steering-free, which is critical for THz FELs and radiation experiments. It also provides a detailed beam trajectory overview by fitting the beam positions measured at beam position monitors (BPMs) using the response matrices and with the earth magnetic fields (EMF) considered, providing a deeper understanding of the intermediate beam trajectory and enabling efficient corrections. In this poster, the analytical model, the robustness test and the experimental performance of this tool will be presented.

Obtaining the complete distribution of a beam in high-dimensional phase space is crucial for predicting and controlling beam evolution. Based on the theory of maximum entropy tomography, we developed an algorithm for reconstructing the four-dimensional (4D) transverse phase space distribution. Our algorithm can take any number of 2D linear projections as constraints, and iteratively converges to the unique numerical solution which is the maximum-entropy distribution satisfying the constraints. Having verified the algorithm with simulation experiments, we plan to use it to conduct 4D phase space tomography in the MEBT and HEBT of the heavy ion linac CAFe II.

The electron accelerator S-DALINAC can be operated in conventional acceleration (CA) and energy recovery (ER) modes. In an ER mode, electrons pass the main linear accelerator (LINAC) twice as often compared to the corresponding CA mode: following the acceleration, the electrons are decelerated to return kinetic energy to the electromagnetic fields inside the cavities of the main LINAC. The recovered energy is recycled during the acceleration of subsequent electrons. However, as a result of the deceleration, the electromagnetic fields are impacted. Thus, the fields and consequently the beam properties after acceleration in ER mode differ from those in CA mode. To compare the beam properties after acceleration present in both modes, a non-destructive diagnostic system is necessary since otherwise the ER mode would be interrupted. For this reason, wire scanners were build and used to measure beam properties in the two-turn CA and the two-turn ER mode. Details on the wire scanners and the measurements are presented.

To convert weak current signals into voltage pulse signals proportionally, a 128-channel readout electronics system is developed. The front-end analogue circuits of this readout electronics system are designed based on the Charge to Frequency Converter (CFC) circuit structure, and the back-end digital board processes the voltage pulse signals. After the performance test in the laboratory and the beam test in PREF, This system can proportionally convert currents from 1 pA to 1 μA into voltage pulse signals with an input dynamic range of 120 dB. The maximum nonlinear error does not exceed ±10%, and the system’s resolution is less than 100 fA. The isolation between the adjacent channels is lower than -114 dB. The system is used not only for beam profile monitoring, but also for the flatness, symmetries and scanning uniformity measurements of slow-extraction beams. The system is of great value in the field of weak beam profile measurements.

In response to CERN's need for alternative imaging solutions of scintillating screens due to the discontinuation of radiation-hardened VIDICON tubes, the single large-core multimode fiber (MMF) has been identified as a potential medium to transmit image signals to a CMOS camera situated away from radiation-prone areas. However, significant challenges in image distortion at the fiber's output end complicate the reconstruction of the original beam distribution. To address this, a novel machine learning-based approach was introduced that utilizes a deep convolutional encoder-regressor network. It first compresses the fiber image into a latent space. Subsequently, a fully connected regression network directly estimates the beam parameters, such as centroids and widths, from the encoder output without the need to reconstruct the detailed image. This contribution will showcase an end-to-end system capable of estimating transverse beam parameters from the MMF output speckle patterns. Offering a safe, camera-preserving solution for beam imaging in high-radiation environments.

As many other light sources, ALBA is also going through an upgrade phase leading to ALBA II. In this context, new Beam Position Monitors (BPMs) have to be designed to fit the reduced vacuum chamber. The buttons and the block were designed to be as compact as possible minimizing the impedance to avoid overheat and maintaining a good signal level. Different shapes and materials were simulated and the best were selected to be produced as prototype. In this proceeding, we present the design process and the simulations that lead to the ALBA II BPM button design.

The classical double-aperture interferometry using the visible part of the synchrotron radiation has been used in accelerators for beamsize measurements since the late 90s. However, this technique provides the beam size projection only in the direction given by the two aperture centers (i.e. only the horizontal or vertical direction). To fully characterize the transverse electron beam ellipse, given by the two semi-axis of the ellipse and its tilt angle, the double-aperture system could be rotated in a process that can take few minutes. Instead, using radio-astronomy techniques, this paper shows a new interferometric method with several apertures by which a full 2d transverse beam characterization is done in real-time.

Several experiments were done to measure the transverse beam size at the NCD ALBA beamline using the Heterodyne Near Field Speckles (HNFS) technique. Inside the FCC collaboration, it was decided to move these experiments to the ALBA Front End 21, where currently an x-ray pinhole camera is working since 2021. The goal is that the two measurement techniques can work alternatively and measure the electron beamsize of the same source point, so that a direct comparison between both techniques can be done. This paper reports the SRW simulations performed in order to investigate the feasibility of the HNFS experiments at this new location. In particular, it focuses on the effect of the dipole radiation and the design of the high energy and high bandwidth monochromator requirements.

The feasibility of X-ray Fresnel diffractometry to measure small beam sizes beyond the resolution of X-ray pinhole cameras is studied for the case of Diamond Light Source. After the Diamond-II upgrade, beam sizes as small as 4 µm are anticipated and are not resolvable by the X-ray pinhole cameras, which are the workhorse for beam size, emittance, and energy spread measurements. X-ray Fresnel diffractometry employs a single slit with an optimised width, producing a double lobe diffraction pattern. The visibility of this double lobe intensity distribution relates to the beam size and promises micron-scale beam size measurement. Numerical studies and simulations have been conducted to assess the feasibility of diffractometry for Diamond Light Source. The parameters for the experimental setup have been determined and preliminary experimental results are presented. Challenges and improvements for achieving this measurement for Diamond-II are discussed.

The Insertion Device (ID) photon beam of a synchrotron can be contaminated with radiation from upstream and downstream bending magnets, causing position measurement errors in blade-type monitors. Beamlines of the low emittance storage ring are particularly sensitive to photon beam position variations, requiring more accurate measurements. To address this, we designed an ionization profile monitor to non-destructively measure the profile and position of the white undulator beam at Korea-4GSR without contamination. Leveraging the relatively large active area of readout devices suitable for small emittance beams we have designed a 1:1 mapping field to defocus photo-ions. Given that the defocusing field can induce errors due to vertical position, we propose a calibration method and validate it using particle tracking simulation.

The Proton Radiation Effects Facility (PREF) aiming for the displacement damage effect research was proposed by XTIPC (Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences) in 2018. The facility was designed and constructed by IMP (Institute of Modern Physics, Chinese Academy of Sciences). The beam commissioning of PREF had been started since August to September of 2023. Four types of instruments, scintillation screen, Faraday cup, scintillator and ionization chamber are implemented for the proton beam profile, intensity, position, efficiency, spill structure. With the beam instruments, the machine reached nearly 95% slow extraction efficiency for all energies from 10 to 60 MeV, 5$\times10^{10}$ particle per second (ppp), 2$\times$2 cm² up to 20$\times$20 cm² scanning area.

SKIF is a synchrotron radiation facility under construction in Novosibirsk. Electron beam energy 3 GeV, beam current up to 0.4 A and extremely low horizontal beam emittance 75 pm$\cdot$rad are convenient to make a high-energy photon source at the main storage ring. Gamma-photons are obtained using Compton backscattering (inverse Compton scattering) of IR, UV and visible laser radiation. Using modern high-power lasers, Compton photons in hundreds-MeV energy range and rates up to 300 MHz can be achieved. Also, higher Compton photon energies (up to 2.6 GeV) can be generated using synchrotron radiation reflected towards the electron beam. A preferable option for photon monochromatisation is tagging photons by recoil electrons with resolution of 0.6%$\dots$0.8% (or $\sim$2 MeV), which is an advantage of ulta-low electron emittance. The discussed Compton source is mainly usable for photonuclear and photohadron processes such as photofission and production of $\pi$, $\eta$, $\Delta$ at nuclei. Also nonlinear QED, EM detectors calibration and other applications are in interest.

Over the past two decades, laser-driven proton radiotherapy devices have garnered significant attention among novel accelerator technologies, due to their high acceleration gradient. Peking University is engaged in the construction and development of CLAPA-II (the Compact LAser Plasma Accelerator II), a proton therapy facility which utilizes a laser-plasma acceleration scheme. This facility comprises two horizontal and vertical beam transmission lines, operating at a repetition rate of 1Hz, capable of delivering 10^8-10^10 protons per second. We have implemented both interceptor and non-interceptor detectors for precise measurements of proton beam. Notably, this is the first instance where an ionization chamber and cavity BPM have been integrated into a laser proton therapy accelerator. To validate the performance of our beam diagnostic system, we have established an offline test platform that simulates the laser proton beam. The results indicate that the offline test resolution of the cavity BPM has achieved 0.2μm in the range of ±3mm. Furthermore, we explored the absolute collection efficiency and particle recombination factor of ionization chamber with ultra-high dose rate proton beams, leveraging the laser-driven ultrashort electron beam generated by Peking University's CLAPA-I facility. This paper provides an overview of the beam diagnosis system's overall layout, accompanied by a detailed description of the detector design and corresponding measurement results.

The China Initiative Accelerator Driven System (CiADS), a multi-purpose facility driven by a 500 MeV superconducting RF linac, is currently under construction in Huizhou, Guangdong. In order to ensure the stable operation of the superconducting linac, we conducted optimization research on the beam quality in the front-end section of CiADS. By using the point scraping method, part of the beam halo particles are removed in advance at the entrance of the LEBT, avoiding the generation of beam halo particles. On the other hand, since the beam extracted from the ECRIS contains a portion of $H^{2+}$ and $H^{3+}$particles, impurity particles may lead to a decrease in the transmission efficiency of downstream accelerators. By separating the mixed beam, it is possible to measure the proportion and phase space distribution of the mixed beam at the exit of the ion source, thereby achieving accurate measurement of the proton beam. This paper mainly outlines the first beam commissioning of CiADS Front end. Additionally, the effectiveness of the point scraping method has been verified through transverse emittance measurement, and the proportion and phase space distribution of the mixed beam was measured. Furthermore, the stability of the ion source was tested, and the centroid shift of the ion source extracted beam was measured.

The 81.25 MHz quarter-wave resonator (QWR) and 162.5 MHz half-wave resonator (HWR) are selected as the main accelerating cavities for the superconducting ion linac of the High Intensity heavy-ion Accelerator Facility (HIAF) at the Institute of Modern Physics (IMP). Six QWR007 (βopt = 0.07) cavities and eight HWR015 (βopt = 0.15) cavities have been fabricated before the mass production to verify the design and production quality control. Two cavities of the both types have been random chosen to surface processing and vertical testing for performance validating before welding helium vessel. In this paper, the development of SRF cavity for HIAF will be addressed, which including the fabrication, surface processing and vertical testing results. The achieved gradients for both cavities have exceeded 60%~100% of requiring operation gradients. The Q0 of both types cavities have met the 2 K operation requirement too. These results inspired to push the cavity production for the HIAF project forward to the mass production stage.

INR RAS linac was developed in late 1970s and build during 1980s. Its timing system is based on the fifty years old technologies and requires full upgrade due to system stability decrease, lack of spare parts, progressing hardware degradation and increase in RF jamming. Moreover, the timing system upgrade should be done without additional accelerator complex shutdowns. In this paper a project of a new timing system that fulfills all requirements is presented. Various features and production peculiarities of the new timing system hardware and software are described. Results of the implementation of new system first parts and its commissioning and plans for future upgrade are discussed.

For future continuous wave (CW) and high-duty-cycle operation of the European XFEL, research and development of the DESY L-band CW photoinjector is ongoing. The implementation of a superconducting radio frequency (SRF) gun operated at 1.3 GHz with a copper photocathode is the baseline option. The electron beam quality, in particular the slice emittance, produced by this injector is key for the successful operation of the free-electron laser. In order to study the beam quality and stability of operation, a dedicated test stand and diagnostics beamline is being developed at DESY. Here, we present an overview of the foreseen diagnostic components and methods at the SRF CW photoinjector test stand.

" Laboratory for Ultrafast Transient Facility" is organically composed of two major categories of core parts: one is a Ultrafast Transient electron microscope cluster; the other is a Ultrafast Transient synchrotron radiation device that provides ultraviolet to X-rays. The first stage of synchrotron radiation device includes a 0.5 GeV linear accelerator as full energy injector, a high-current storage ring, and a beam line. For the construction of the linear accelerator beam diagnostics system, the main focus is on the reliability and maintainability of the system. The system mainly includes beam position measurement system , bunch charge measurement system and beam profile measurement system; the article will mainly introduce the composition and design of these systems.

Shenzhen Innovation Light-source Facility (SILF) is designed to be the so-called forth generation synchrotron radiation light source operating at 3.0 GeV, 300 mA, and with the emittance less than 100 pm∙rad. With the increase in luminosity of the light, higher stability of the electron beam is required, which may also result in increased measurement diversity and accuracy. Here, an overview of the SILF beam instrumentation system is provided, along with detailed descriptions of its key technology, including the Beam Position Monitor (BPM) and electronics, transverse feedback kicker and electronics, and beam transverse size measurement. Additionally, the future development of the beam instrumentation system is discussed.

The SESRI (Space Environment Simulation and Research Infrastructure) is a large-scale space science and technology experimental research accelerator clusters, the 300MeV proton and heavy ion accelerator is the key part. It consists of an ECRIS (Electron Cyclotron Resonance Ion Source), a linac cascade injector, a compact synchrotron, and three irradiation terminals. The proton and HI with 2MeV and 5.6MeV/U can be injected, and slowy extracted from the ring with the RF-KO and Ese. The operation cycle is about 3-10s. The Scintillation Screens are used to monitor the beam profile. They are driven by motors for the different orbits. The wire scanners are used to measure the beam profile during the acceleration process, in order to obtain the beam emittance; In order to meet the requirements of large current range, the BPM system adopts a Libra adjustable gain amplifier, and uses Libra Hadron to achieve BBB and 1kHz closed orbit measurement. RF-KO provides a transverse extraction electric field.Amplitude and frrequency modulation are used for the extraction signals. At the same time, a feedback system based on excitation and fast quadrupole is adopted. Through the above methods, the uniformity of beam extraction is greatly improved.

Huazhong University of Science and Technology is building a cyclotron-based Proton Therapy Facility (HUST-PTF). The facility mainly consists of a 240MeV superconducting cyclotron, a beam transport line, a fixed treatment room and two rotational treatment rooms. HUST-PTF uses three kinds of detectors, Scintillation, Faraday cup and ionization chamber, for the beam param-eter measurements. In terms of structure, the HUST PTF beam diagnostic system is built according to the standard distributed three-layer structure, which is divided into hardware device layer, data processing layer and GUI layer. Different protocols are used to communicate be-tween the three layers, which can improve reliability and expand flexibly in each layer.

The linac of INR RAS is а high-intensity accelerator of protons and H-minus ions, which is used for a complex of neutron sources, isotope production, proton irradiation and investigations in proton flash therapy. A non-destructive beam instrumentation plays a key role in the linac tuning. The general peculiarity of this multi-component system is that all detectors are home-made devices with a wide operation range and can be used at different ion linacs with a minimum adaptation to beam parameters. Beam current transformers for standard and in-air measurements, resonance and capacitive position and phase monitors, BIF-monitor for 1D and beam cross-section monitor for 2D non-destructive profile diagnostics. Different operation features and manufacturing peculiarities are presented in this paper. Results of implementation, operation and continuous upgrade are described. Also easily scalable typical designs of some detectors are discussed.

The Nuclear Data Production System (NDPS) was constructed at Rare Isotope Accelerator complex for ON-line experiments (RAON) to produce nuclear data for neutron-induced reactions at a few tens of MeV. For the neutron time-of-flight measurement, various neutron detectors, such as gas-filled Parallel Plate Avalanche Counter (PPAC), MICRO-MEsh-GASeous (MICROMEGAS), and EJ-301 liquid scintillation detectors, were installed in the NDPS neutron beamline. The NDPS recently performed its first beam commissioning with 16 MeV/nucleon 40Ar ion beams. For the measurement of the neutron beam, EJ-301 liquid scintillation detectors and activation foils (natAl, natFe, natZr, natAu, natBi, etc) were used to measure the neutrons from the graphite target. In this presentation, we report a detailed description of the NDPS neutron detection system with its current status.