We report on a simple method to perform an absolute calibration of the magnetic beam analyser of the reaccelerator ReA3 at the National Superconducting Cyclotron Laboratory. The method is based on the time of flight between two beam stoppers 7.65 m apart. Based on two independent time-of-flight measurements at three different beam energies, the beam analyser magnet is calibrated with an accuracy of 0.12 %, corresponding to a beam energy accuracy of 0.24 %.

New projects of high-energy hadron colliders could be improved significantly using electron cooling technique. But the source of high-current relativistic electron beam appears to be a technical challenge. Indeed, intrinsic energy limitations of high-voltage DC accelerators lead to necessity to use not static, but vortex, electrical field for acceleration. Induction and radiofrequency (RF) accelerators just use such field. Moreover, to keep small enough damping times at high energies, it needs to increase electron peak current to tens of amperes. The feasibility of RF energy recovery linac (ERL) for electron cooling is discussed. The ERL of the Novosibirsk free electron laser facility is used as a reliable prototype.

The European Spallation Source (ESS) will be a 5 MW pulsed neutron source, relying on a 2 GeV linac delivering 2.86 ms long pulses with 14 Hz repetition rate. During the commissioning and the tuning phases of the ESS linac, four Faraday Cups (FC) serve as beam dumps and provide an absolute measurement of the proton beam current. This contribution summarizes the challenges in the design and production of all the FCs mainly requiring: - Thermo-mechanical analysis to keep heat load and mechanical stress below the mechanical limits; - Inclusion of an electron repeller to prevent the escape of secondary charged particles from the cup that would limit the accuracy of the current measurements; - Monte Carlo simulations to compute material activation, dose at contact and corresponding necessary shielding; - Design of high-resolution detection circuits for low current to fulfill the requirements on bandwidth, gain and noise. In addition, the performance of the LEBT FC during the commissioning of the ion source and LEBT is reported. The LEBT FC system is under continuous improvement and serves as benchmark for the protection from unwanted operation, and in case of actuator or cooling faults.

The free-electron laser facilities driven by a superconducting radio-frequency (SRF) linac provide high-repetition-rate electron beam, which makes it feasible to feed multiple undulator lines at the same time. In this paper, we study a method of controlling the beam energy of multiple electron bunches by off-frequency detuning of the SRF linac. Based on the theoretical analysis, we present the optimal solutions of the method and the strategy to allocate linac energy for each possible off-frequency detune. The initial acceleration phases before detuning of the SRF linac can be optimized to reduce the necessary SRF linac energy overhead. We adopt the LCLS-II-HE configuration as an example to discuss possible schemes for two undulator lines.

Heavy ions of outer space are the major threat to the correct operation of modern spacecraft electronic components due to single event effects (SEE), which can result in a failure of spacecraft system equipment. For modeling heavy-ion space environment in testing laboratories, ion-accelerator-based test facilities are used. ISDE in cooperation with JINR have created and currently operates one of the few in the world and unique in Russia test facilities on the basis of U-400 and U-400M accelerators that provide all types of SEE radiation tests of electronic components of any functional class. The test facilities allow to irradiate devices under test in the following test environments: range of ions from С to Bi; initial energy from 3 to 60 (for light ions) MeV/A; LETs (Si) from 1 to 100 MeV×cm²/mg; ranges (Si) from 0.03 to 2 mm (depending on the energy); adjustable fluxes from 10 to 10⁺⁵ particles/(cm² × s); irradiation area up to 200×200mm; beam nonuniformity less than 10 %. The paper presents a detailed description of the test facilities, techniques for obtaining large irradiation area, beam energy characteristics determination, fluence and nonuniformity estimation.

Novel light-matter interaction experiments conducted in free-electron lasers, ultrafast electron diffraction instruments and extreme light infrastructures require synchronous operation of microwave sources with femtosecond pulsed lasers [1]. In particular, Ti:sapphire lasers have become the most common near-infrared light source used in these facilities due to their wide-range tunability and their ability to generate ultrashort pulses at around 800-nm optical wavelength [2]. Therefore, a highly sensitive optical-to-microwave phase detector operating at 800 nm is an indispensable tool to synchronize these ubiquitous lasers to the microwave clocks of these facilities. Electro-optic sampling is one approach that has proven to be the most precise in extracting the relative phase noise between microwaves and optical pulse trains. However, their implementation at 800-nm wavelength has been so far limited [3]. Here, we show a balanced optical-microwave phase detector designed for 800-nm operation based on electro-optic sampling. The detector has a timing resolution of 0.01 fs RMS for offset frequencies above 100 Hz and a total noise floor of less than 10 fs RMS integrated from 1 Hz to 1 MHz.

At present the Facility for Antiproton and Ion Research (FAIR) is under construction at the GSI site. As part of the FAIR project the beamlines of the High Energy Beam Transport (HEBT) section interconnect the synchrotrons, storage rings and experimental caves. The large range of beam energies (MeV to GeV) and beam intensities up to 10¹² particles per pulse for uranium, or up to 2·10¹³ particles per pulse for protons, demand in many cases for purpose-built beam diagnostic devices. Presently, the main diagnostic components are being manufactured by international in-kind partners in close collaboration with GSI. This contribution presents an overview of the beam instrumentation layout of the FAIR HEBT and summa-rizes the present status of developments for HEBT beam diagnostics. We focus on the status of the foreseen beam current transformers, particle detectors, scintillating screens and profile grids.

HIAF (High Intensity heavy ion Accelerator Facility) is a project proposed by IMP (Institute of Modern Physics, Chinese Academy of Sciences). This paper designs a digital controller for Bring in HIAF dipole power supplies system, which is several circuit boards consist of high precision ADC, optical fiber module, DDR3 SDRAM, Gigabit Ethernet module. It uses Cyclone V SX SoC FPGA, which integrated with dual-core ARM Cortex-A9 MP Core processor. This paper explains the hardware and software architecture of the controller and how can it improve power supplies performances. The FPGA finishes the PI regulating and PWM modulation. The ARM is responsible for data pre-setting, web service, database, and power supplies detection and protection management. At the end, this paper gives the output measurements when the controller is used in the prototype, which verifies the rationality and reliability of the design.

We outline the fundamental processes of coherent radiation emission from a bunched charged particles beam [1]. In contrast to spontaneous emission of radiation from a random electron beam that is proportional to the number of particles N, a pre-bunched electron beam emits spontaneously coherent radiation proportional to N² through the process of (spontaneous) superradiance (SP-SR) (in the sense of Dicke’s [2]). The SP-SR emission of a bunched electron beam can be even further enhanced by a process of stimulated-superradiance (ST-SR) in the presence of a seed injected radiation field. These coherent radiation emission processes are presented in term of a radiation mode expansion model, applied to general free electron radiation schemes: Optical-Klystron, HGHG, EEHG, and coherent THz sources based on synchrotron radiation, undulator radiation or Smith-Purcell radiation. The general model of coherent spontaneous emission is also extended to the nonlinear regime - Tapering Enhanced Stimulated Superradiance (TESSA) [3], and related to the tapered wiggler section of seed-injected FELs. In X-Ray FELs these processes are convoluted with other effects, but they are guidelines for strategies of wiggler tapering efficiency enhancement.

The NICA accelerator complex contains two electron coolers, one sits at booster and another at NICA collider. They have requirements for the vacuum of 10⁻¹¹ mbar. Despite the coolers have different design the problems of getting vacuum are similar, lack of space along vacuum chambers, presence of the electron beam and oxide cathode usage. The solutions for achieving such a strict requirements are discussed in the article.