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.

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 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.

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.

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.

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.

The 60 MeV Proton Radiation Effects Facility (PREF) spent nearly 1 month at the commissioning phase, during which the multi-strip ionization chamber (MIC) at the experimental terminal offered the core parameters, beam spot, scanning area, scanning uniformity, beam flux. However, the projection distribution provided by the MIC loses some information, such as the flux and the uniformity in a selected area less than the scanning area. This paper used a method of two-dimensional reconstruction to provide a 2D uniformity of selected area. Revealing the trace of the pencil beam at a sampling rate of 10 kHz.

The embedded EPICS control system for beam measurement is implemented based on the Zynq 7z020 SoC, which enables efficient and reliable real-time data acquisition, transmission, processing, and PV publishing of embedded IOCs. The data acquisition module uses a 24-bit ADC with a sampling frequency of 10Msps, which enables continuous sampling and data processing of detector signals, and interlocking signals can be output within 10μs. Data transmission and communication from the PL to the PS is achieved through the AXI bus, and the real-time data of different BRAMs and registers is accessed by manipulating memory base addresses and offsets. The ADC raw data with a continuous data rate of 200K/s can be stored without losing points. Through long-term online testing, the beam measurement electronics system can accurately monitor beam signals, output interlocking signals in a timely manner, and the software and hardware systems work stably and reliably for a long time. It can be widely used for signal measurement of beam loss, CT, Faraday cup, integral coil, power ripple, ionization chamber, wire scanner, etc.

Providing 10 to 60 MeV proton beams, the PREF (Proton Radiation Effects Facility) is dedicated to the displacement damage effect experiments. The slow extracted beams from the synchrotron are delivered to two experimental terminals, which required the flux as constant as possible. To characterize the slow extraction parameters, scintillators and ionization chambers are equipped in the transport line and the terminals. The frequency response reveals the major influencing factor, power supply ripples. The duty factor reached over 90% shows the high slow extraction quality of the new accelerator.

The High Intensity Heavy-ion Accelerator Facility (HIAF), currently under construction, is a complex machine that couples a Continuous Wave (CW) superconducting ion Linear accelerator (iLinac) with a high-energy synchrotron to produce various stable and radioactive intense beams with high energies. The machine has a versatile operation mode which requires a high flexibility and reliability to the Machine Protection System (MPS). A customized and robust MPS is designed and developed to give the readiness of the machine for operation, to mitigate and analyze faults related to the relative damage potential. To get a high speed and have a high level of reliability, all interlock signal processing is processed on radiation-tolerant Field-Programmable Gate Arrays (FPGA) with triple or dual redundancy, as well as with a fail-safe design. By implementing a multiprocessing platform system-on-chip FPGA, the HIAF MPS can be tightly integrated with other systems to maximize availability pinpoint failures for operations, and give the postmortem analysis. This paper will describe the architecture of the interlocks linking the protection systems, the strategies to manage the complexity, the detailed components, and the interlock logic of the customized HIAF MPS, as well as the test and verification of the prototype.

Dipole magnet vacuum chambers are among the critical and costly components of rapid-cycling accelerator facilities. Alternative approaches to traditional ceramic chambers have been explored for the implementation of fast-ramping dipole-magnet vacuum chambers, including thin-wall metallic beam pipe chambers strengthened with transverse ribs. Here, we report a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber, which is designed for HIAF project to reduce manufacturing difficulty and cost, shorten the production cycle, and improve the quality. Because the beam impedance aspects are highly important for beam stability, comprehensive studies were undertaken to characterize the impedance of the 3D-printed titanium alloy cage inside thin-wall vacuum chamber. The beam-coupling impedance of the new thin-wall vacuum chamber were studied numerically. Strategies for further reducing the beam-coupling impedance were explored. In addition, impedance bench measurements using the “half wavelength” resonant method were conducted to identify the longitudinal and transverse impedance of this thin-wall vacuum chamber prototype experimentally. The simulated and measured results for the impedance were consistent. Furthermore, a campaign for resonance-check measurements on this thin-wall vacuum chamber prototype was launched. This novel thin-wall vacuum chamber structure has been ready for installation in the Booster Ring (BRing).