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 Cryogenic Current Comparator (CCC) is a superconducting SQUID-based device, which measures extremely low electrical currents via their azimuthal magnetic field. Triggered by the need for nA current measurement of slow extracted beams and weak beams of exotic ions in the storage rings at FAIR and CERN, the idea of the CCC as a diagnostics instrument has been revitalized during the last ten years. The work of a collaboration of institutes specialized on the various subtopics resulted in a large variety of CCC types with respect to field-pickup, magnetic shielding, SQUID types and SQUID coupling. Many of them have been tested under laboratory and under beamline conditions, which formed a detailed picture of the application possibilities for CCCs in accelerators. In parallel to CCC detector development the cryogenic support system has steadily been optimized, to fulfil the requirement of a standalone liquid helium cryostat, which is nonmagnetic, fit for UHV application, vibration damped, compact and accessible for maintenance and repair. We present the major development steps of the CCC for FAIR. The latest beamtime results are shown as well as recent tests with the cryogenic system. The most promising CCC type for FAIR is the so called Dual-Core CCC (DCCC), which runs two pickups in parallel with independent electronics for noise reduction. The magnetic shielding has an axial meander geometry, which provides superior attenuation of external magnetic noise.

Accurately measuring the beam phase is critical when determining the ideal RF cavity parameters for beam acceleration. In the past, only Fast Current Transformers (FCTs) were used to measure the beam phase. However, with the upcoming upgrade of the MEBT section for the CSNS-II project, shorted stripline-type BPMs will now be utilized to measure beam position, phase, and energy. LIBERA singlepass electronics are employed to measure the beam position and phase from the BPMs. Pairs of BPMs were used to measure beam phase shift, which can also be used to calculate beam energy. This paper compares beam phase measurement systematically by BPMs and FCT.

A bunch-by-bunch beam monitor electronics for High Energy Photon Source (HEPS) was designed. The hardware of electronics consists of analog signal acquisition board and digital signal processing board. The software consists of underlying firmware and application software. The sampling frequencyis 500 MHz, and the bandwidth is 1 GHz. The electronics digitizes four analog signals from BPM probe, and ZYNQ chip was used to process the beam data and calculate the charge of each bunch. This system has been used in HEPS booster and will be used in HEPS storage ring.

In this work, we analyze the movement of the electrons and ions inside a Faraday cup with different biasing of the collector cup, drift tube and suppressor ring. The possible error due to wrong biasing is also investigated. The particle pass is tracked in different biasing configurations. Also, the effect of stray electrons and ions, which are generated due to gas ionization along the beam pass, is studied. Through the analysis, we found the best biasing for the proposed configurations of the Faraday cup.

High Energy Photon Source (HEPS) is the fourth-generation light source under construction in China. The electron gun system is the origin of beam acceleration. This article introduces the wide range and high precision grid-cathode modulation of beam current for the HEPS electron gun system. Its grid-bias voltage adjustment is as fine as 0.01V. Cathode filament current and voltage ripple＜0.1%. Its grid-bias voltage adjustment accuracy reaches 0.01V. The cathode filament current and voltage ripple <0.1%. The beam test results show that the beam current amplitude stabilization of 2.37% (small current)，0.13% (high current), beam current time jitter 12.459ps. Meets physical requirements for a wide range of injector from 2.8nC to 7nC.

CERN H- Linac 4 (L4) and ion Linac 3 (L3) operate with millisecond beam pulses, which pose a challenge for beam current measurements based on Fast Beam Current Transformers (FBCTs). In the past the low cut-off frequencies of the FBCTs were actively lowered using a combination of transimpedance (TI) amplifiers and integrating amplifiers. Unfortunately, in many locations such amplifiers were sensitive to interference from neighbouring power systems. The situation was particularly difficult in L3, where in addition to long beam pulses, the challenge was also small beam currents. The interference problems had been addressed for years with limited success and finally it was decided that the whole FBCT front-end electronics should be renovated, with the main objective being to improve the immunity to interference. This paper describes the evolution of the FBCT front-end electronics and installations, which has finally allowed reliable beam current measurements, whose examples are provided. The key improvement was the use of small TI amplifiers directly connected to the FBCTs, which in addition simplified installations in both linacs. The TI amplifiers provide an active low impedance load to the FBCTs, extending their time constants by some two orders of magnitude, as compared to operation with a 50 Ohm load. Challenges of the TI amplifier implementation are described, along with particularities of their beam commissioning.

Non-intrusive cavity beam diagnostic devices offer advantages such as high induced signal and sensitivity. The size of the resonant cavity is inversely related to its operating frequency, resulting in an increase in size at lower operating frequencies, thus limiting its applicability. Therefore, exploring how to modify the cavity structure to regulate its internal electromagnetic field distribution and achieve a decrease in operating frequency has become a research topic of significant importance. In current cyclotron-based proton therapy devices, challenges arise from low beam repetition rates and weak intensities. These characteristics make traditional cavity beam diagnostics ineffective, resulting in monitoring blind spots during treatment. To tackle this challenge, this paper introduces a metamaterial-loaded cavity beam current monitor (BCM). Electromagnetic simulations reveal that this approach significantly reduces the size of the cavity under low-frequency operational settings. Moreover, this technique addresses the problem of high energy loss observed in conventional dielectric-loaded cavity BCM, effectively improving sensitivity. The all-metal metamaterial structure also circumvents difficulties associated with processing. This innovative design presents a fresh avenue for exploring the development of compact cavity beam diagnostics suitable for low-frequency operational environments.

Accelerators at J-PARC, a high-intensity proton accelerator facility, consists of a 400 MeV linac, 3 GeV RCS, and 30 GeV MR. The RCS is aiming for steady operation with output beam power of 1 MW, while the MR has achieved its initial target of 750 kW by shortening its operating cycle, and further beam tunings and developments are underway to achieve the next target of 1.3 MW. At J-PARC, it is necessary to suppress beam losses to an extremely low level to suppress the activation of the accelerator devices, and thus it is essential to improve the measurement accuracy of beam loss and current monitors. Particularly in MR, with the significant improvement in beam power, there is a need to improve the measurement accuracy of the beam current monitors from 1% at the present. Accordingly, the current monitors have been calibrated regularly, but have not been carried out in a unified manner throughout the accelerators. In this presentation, we will report on the calibration methods and its accuracy.

The North Area facility (NA), built in the 1970s at CERN, hosts several secondary beam lines for a large variety of physics experiments: Neutrino Platform, Dark matter, high energy physics, R&D, detector validation etc. 400 GeV/c primary proton beams, extracted from the SPS ring, are split along the transfer lines to fire on 4 targets and serve the users with secondary particles such as e-, e+, muons, pions, hadrons, kaons... Within a typical slow extraction scheme of 4.8 s, one gets a spill intensity of about 4E13 protons heading to the splitters. Available beam intensity monitors are ageing fast and are accurate up to 10% only, which is not compatible for future high intensity physics programs and new demanding specifications for the beam instrumentation. In the wake of the NA consolidation project, it is proposed to measure the beam intensity with a Cryogenic Current Comparator (CCC). Such devices installed at FAIR (GSI) and in the Antimatter Factory (CERN) have proven to be operational and having a resolution of a few nA. This paper describes the roadmap and challenges to come for the development of the new CCC.

The energy characterization of an RF ion beam, generated by an inductively coupled plasma (ICP) RF ion source, has been conducted using a spherical electrostatic energy analyzer. The RF ion source, operating at an applied frequency of 13.56 MHz and a power level of 300 W, was assessed in both pulse and continuous modes. The ion energy spectrum of the hydrogen beam was meticulously measured under various conditions, with the extraction voltage ranging from 1 to 10 keV. The analysis revealed variations in the energy profiles under different operational conditions, providing insights into the ion source's performance and optimization. These findings contribute to a deeper understanding of RF ion beams for enhancing the design and efficiency of ion sources used in particle accelerators and related technologies. The importance of precise energy spectrum measurements in enhancing the efficiency and functionality of ion sources in advanced beam instrumentation is underscored by this research.

Beam lifetime measurements are an important tool to characterize the key storage ring and machine performance parameters. They are usually derived from the dc current transformer (DCCT) data, and their accuracy depends on DCCT noise and data duration period. However, accurate dc current and fast lifetime determination are in contradiction and have to be balanced carefully. In this contribution, a model is presented which relates the relative accuracy in lifetime determination and the DCCT noise with the acquisition time. For the PETRA IV project at DESY (Hamburg, Germany) which aims to upgrade the present PETRA III synchrotron into an ultra low-emittance source, according to this model a lifetime determination to the level of 1% should be possible within 5-6 s acquisition time.

The North Area facility (NA) receives the 400 GeV proton beam through a slow extraction process at the CERN Super Proton Synchrotron (SPS). To improve the SPS spill quality, it is crucial to monitor the spill intensity from the nA up to the µA range with a bandwidth extending from a few Hz up to several GHz along the extraction line. The most promising measurement options for this purpose are the Optical Transition Radiation-PhotoMultiplier (OTR-PMT) and the Cherenkov proton Flux Monitor (CpFM). This document presents recent improvements of both devices based on the operational experience gathered throughout the 2023 Run. It includes a detailed analysis and discussion of the present performance, comparing the capabilities of each instrument. Additionally, future ideas for multi-GHz detectors, particularly for the SHIP collaboration, are also outlined.