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SPring‐8‐II is a major upgrade project of SPring‐8 that was inaugurated in October 1997 as a third‐generation synchrotron radiation light source. This upgrade project aims to achieve three goals simultaneously: achievement of excellent light source performance, refurbishment of aged systems, and significant reduction in power consumption for the entire facility. A small emittance of 50 pm rad will be achieved by (1) replacing the existing double‐bend lattice structure with a five‐bend achromat one, (2) lowering the stored beam energy from 8 to 6 GeV, (3) increasing the horizontal damping partition number from 1 to 1.3, and (4) enhancing horizontal radiation damping by installing damping wigglers in long straight sections. The use of short‐period in‐vacuum undulators allows ultrabrilliant X‐rays to be provided while keeping a high‐energy spectral range even at the reduced electron‐beam energy of 6 GeV. To reduce power consumption, the dedicated, aged injector system has been shut down and the high‐performance linear accelerator of SACLA, a compact X‐ray free‐electron laser (XFEL) facility, is used as the injector of the ring in a time‐shared manner. This allows the simultaneous operation of XFEL experiments at SACLA and full/top‐up injection of the electron beam into the ring. This paper overviews the concept of the SPring‐8‐II project, the system design of the light source and the details of the accelerator component design. [ABSTRACT FROM AUTHOR]

Organic compounds can solve many problems that lithium ion batteries currently face, such as the unsustainability and limited capacity of inorganic electrodes, due to their abundance, renewability and designability. As a kind of electroactive porous polymer, covalent triazine-based frameworks (CTFs) have shown good potential in energy storage. However, their synthesis usually requires high reaction temperature and a long reaction time or employs toxic organic reagents, resulting in uncontrollable structures, high synthesis cost and negative environmental impact. Herein, an AlCl3–NaCl–KCl ternary molten salt system with a low eutectic point (∼93 °C) was used for the first time for the synthesis of CTFs, and products with good crystallinity and an AB stacking structure were prepared even at 180 °C, the lowest temperature reported for the synthesis of CTFs in molten salt. Electrochemical tests further indicated that AB-stacked CTFs exhibited better electrochemical performance than the AA-stacked one and could behave as both the cathode and anode of Li-ion batteries. As a consequence, a rocking-chair full cell composed of the CTFs@Li3PO4 cathode and a CTF-based anode had been assembled with an initial discharge specific capacity of 101.2 mA h g−1 at 0.2 A g−1. Ex situ FTIR and XPS tests revealed the reversible Li+ insertion/extraction at C＝N of triazine rings and C＝C of cyclohexadiene rings for the anode and the synergistic lithium storage of triazine rings and Li3PO4 based on in situ p-type doping/dedoping of CTFs in the cathode. The concept of a biphase coupled cathode (BPCC) that combines p-type organic molecules and lithium salts for designing a rocking-chair all-organic lithium ion battery will inspire the study of high-energy organic lithium ion batteries beyond dual-ion batteries and open a new avenue for organic energy storage. [ABSTRACT FROM AUTHOR]

The Hefei Advanced Light Facility (HALF) injector comprises 40 S-band 3-m traveling wave accelerating structures, capable of delivering electrons with a full energy of 2.2 GeV into the storage ring. To mitigate emittance degradation caused by field asymmetry in the coupler cavity, the coupler design incorporates a racetrack and a short-circuit waveguide. This paper introduces the microwave design and provides the parameters of the HALF accelerating structure. Two design methods for couplers were compared, and the effectiveness of using the undercoupling (for which the coupling coefficient β calculated by Kyhl's method is less than 1) to match the output coupler was experimentally demonstrated. The nodal-shift method and bead-pull method were used to test and tune the structures of different output coupler designs during the cold test, demonstrating the tuning results under actual conditions. Experiments were conducted under different load conditions to calculate the local reflection coefficient of the output coupler. The results show that both the accelerating structure design and the tuning results meet the HALF requirements. [ABSTRACT FROM AUTHOR]

An organic cathode material for zinc-ion batteries shows a reliable proton transport mechanism. It uses a pyrazine ring as the energy storage unit and H+ as the shuttle ion, enabling high functionality utilization with rapid redox kinetics. [ABSTRACT FROM AUTHOR]

Multiple harmonic generation is a key issue for coherence radiation generated by an electron beam modulated by the seeding laser. A new multiple harmonic generation scheme by combining the angular dispersion-induced microbunching (ADM) with the transverse echo effect, which can be easily generated by using pulsed dipoles, a pulsed quadrupole and a pulsed multipole, is investigated in a multi-bend achromatic storage ring. Simulation results demonstrate a triple of harmonic number compared to the case of pure ADM, making it possible to generate coherent extreme ultraviolet radiation in storage rings. [ABSTRACT FROM AUTHOR]

The advent of diffraction‐limited storage rings (DLSRs) has boosted the brilliance or coherent flux by one to two orders of magnitude with respect to the previous generation. One consequence of this brilliance enhancement is an increase in the flux density or number of photons per unit of area and time, which opens new possibilities for the spatiotemporal resolution of X‐ray imaging techniques. This paper studies the time‐resolved microscopy capabilities of such facilities by benchmarking the ForMAX beamline at the MAX IV storage ring. It is demonstrated that this enhanced flux density using a single harmonic of the source allows micrometre‐resolution time‐resolved imaging at 2000 tomograms per second and 1.1 MHz 2D acquisition rates using the full dynamic range of the detector system. [ABSTRACT FROM AUTHOR]

The advent of diffraction-limited storage rings (DLSRs) has boosted the brilliance or coherent flux by one to two orders of magnitude with respect to the previous generation. One consequence of this brilliance enhancement is an increase in the flux density or number of photons per unit of area and time, which opens new possibilities for the spatiotemporal resolution of X-ray imaging techniques. This paper studies the time-resolved microscopy capabilities of such facilities by benchmarking the ForMAX beamline at the MAX IV storage ring. It is demonstrated that this enhanced flux density using a single harmonic of the source allows micrometre-resolution time-resolved imaging at 2000 tomograms per second and 1.1 MHz 2D acquisition rates using the full dynamic range of the detector system.

While the dissociative recombination (DR) of ground-state molecular ions with low-energy free electrons is generally known to be exothermic, it has been predicted to be endothermic for a class of transition-metal oxide ions. To understand this unusual case, the electron recombination of titanium oxide ions (TiO+) with electrons has been experimentally investigated using the Cryogenic Storage Ring. In its low radiation field, the TiO+ ions relax internally to low rotational excitation (≲100 K). Under controlled collision energies down to ∼ 2 meV within the merged electron and ion beam configuration, fragment imaging has been applied to determine the kinetic energy released to Ti and O neutral reaction products. Detailed analysis of the fragment imaging data considering the reactant and product excitation channels reveals an endothermicity for the TiO+ dissociative electron recombination of (+4 ± 10) meV. This result improves the accuracy of the energy balance by a factor of 7 compared to that found indirectly from hitherto known molecular properties. Conversely, the present endothermicity yields improved dissociation energy values for D0(TiO) = (6.824 ± 0.010) eV and D0(TiO+) = (6.832 ± 0.010) eV. All thermochemistry values were compared to new coupled-cluster calculations and found to be in good agreement. Moreover, absolute rate coefficients for the electron recombination of rotationally relaxed ions have been measured, yielding an upper limit of 1 × 10−7 cm3 s−1 for typical conditions of cold astrophysical media. Strong variation of the DR rate with the TiO+ internal excitation is predicted. Furthermore, potential energy curves for TiO+ and TiO have been calculated using a multi-reference configuration interaction method to constrain quantum-dynamical paths driving the observed TiO+ electron recombination. [ABSTRACT FROM AUTHOR]

A measurement of the spin observables in external target and storage ring experiments requires a comparison of interactions of oppositely polarized beams. The ideal way to reduce systematic effects is to store bunches of opposite polarization in the same fill. Here we discuss how such bunches can be organized based on the extended pilot-bunch principle. [ABSTRACT FROM AUTHOR]

To search for proton Electric Dipole Moments (EDM) using proton storage ring with purely electrostatic elements, the concept of frozen spin method has been proposed by Brookhaven National Laboratory. This method is based on two facts: in the equation of spin precession, the magnetic field dependence is entirely eliminated, and at the "magic" energy, the spin precession frequency coincides with the precession frequency of the particle momentum. In case of deuteron, we have to use the electrical and magnetic field simultaneously, keeping the frozen spin direction along the momentum as in the pure electrostatic ring. Later, Yu. Senichev proposed the concept of quasi-frozen spin, in which the spin oscillates around the direction of the pulse within half the value of the advanced phase of rotation in magnetic arcs, each time returning back in deflectors with an electrostatic field. Due to the low value of the anomalous magnetic moment of deuteron, an effective contribution to the expected EDM effect is reduced only by a few percent compared with frozen spin method. In this work, we consider the adapted structure of the NICA and Nuclotron synchrotrons, in which the "quasi-frozen spin" option can be implemented. The advantage of the "quasi-frozen spin" concept is the possibility of using synchrotrons already existing in the world that are not focused on studying EDM, which makes this method the only one possible for the accelerators of the NICA complex. [ABSTRACT FROM AUTHOR]

Within the beamlines of diffraction-limited storage rings, the liquid-metal-bath cooling scheme is a prevalent choice for the cooling of high-heat load mirrors. This study employs the finite element analysis method to evaluate the thermal deformations of liquid-metal-bath horizontally deflecting mirrors in the Hefei Advanced Light Facility. In particular, we introduce a novel optimization strategy to obtain the optimal thermal deformation scenario, which also satisfies mechanical design requirements. Moreover, a concurrent optimization approach across multiple structural parameters of mirrors is adopted to attain globally optimal thermal deformation. Following the optimization of the mirror's structural parameters, the curvature radius increases to 227 km, while the residual slope error decreases to 36.3 nrad at 6 eV in the meridian direction. The ray tracing analysis of the beam demonstrates a considerable reduction in the influence of thermal deformation on the beam's focal point. This work proposes an optimization method for designing cooling schemes under mechanical constraints. [ABSTRACT FROM AUTHOR]

One of the fundamental processes in nuclear physics is nuclear excitation by electron capture (NEEC). Having been proposed theoretically for almost 50 years, the experimental confirmation of NEEC is still missing, making it imperative to validate this process. In this paper, we propose a new experimental method based on the anti-coincidence principle to search for the long-anticipated NEEC phenomenon, which involve heavy-ion storage rings. Our calculations indicate that the proposed experimental setup, storage ring, have the potential to surmount background noise, particularly Radiative Recombination (RR) and Coulomb Excitation (CE), and offer a high likelihood of discovering the long- awaited NEEC process. [ABSTRACT FROM AUTHOR]

A multi‐objective genetic algorithm (MOGA) is a powerful global optimization tool, but its results are considerably affected by the crossover parameter ηc. Finding an appropriate ηc demands too much computing time because MOGA needs be run several times in order to find a good ηc. In this paper, a self‐adaptive crossover parameter is introduced in a strategy to adopt a new ηc for every generation while running MOGA. This new scheme has also been adopted for a multi‐generation Gaussian process optimization (MGGPO) when producing trial solutions. Compared with the existing MGGPO and MOGA, the MGGPO and MOGA with the new strategy show better performance in nonlinear optimization for the design of low‐emittance storage rings. [ABSTRACT FROM AUTHOR]

In the scope of the latest upgrade of the Swiss Light Source, five hard X‐ray beamlines will be constructed or rebuilt. To use synergies between these beamline projects, a concept is developed here for hard X‐ray beamlines that is tailored to the new storage ring. Herein, this concept is described from the source, via the front end, to the beamline optics. The latter will be outlined in detail, including a new and modular concept for hard X‐ray monochromators, focusing optics and heat‐load management. With a simple, easy‐to‐operate and robust beamline design, the new beamlines will greatly profit from the increased brilliance of the new storage ring. The performance increase is up to four orders of magnitude, while the beamline concept allows for the broad application of experimental techniques, from propagation‐based methods, such as phase‐contrast tomography, to imaging techniques with nanometre resolution. At the same time, spectroscopy experiments are possible as well as high‐performance serial X‐ray crystallography. [ABSTRACT FROM AUTHOR]

Heavy-ion storage rings allow for storing secondary ion beams for extended periods of time. Sophisticated beam manipulation techniques, detection capabilities and thin targets provide unique conditions for a broad range of physics experiments. In this work, the investigations related to nuclear isomeric states are reviewed. [ABSTRACT FROM AUTHOR]

Steady-State Microbunching (SSMB) has been proposed as a concept to generate coherent synchrotron radiation at an electron storage ring. SSMB promises to supply kilowatt level average power radiation in the extreme ultraviolet regime, meeting the power level demands for lithography applications that presently cannot be fulfilled by established accelerator technologies. SSMB is under theoretical and experimental study, building on a proof-of-principle (PoP) experiment at the Metrology Light Source which previously showed the viability of the idea. Here we report experimental findings from systematic studies in the ongoing SSMB PoP experiment, where microbunching is generated from an energy modulation imposed by a laser of wavelength 1064 nm. The results confirm the expected dependence of the microbunching process on modulation amplitude and show that the influence of transverse-longitudinal coupling dynamics is as predicted. This confirmation of key parts of the SSMB theory establishes a solid footing for continuing the proof-of-principle efforts towards the goal of constructing a prototype SSMB light source facility. Steady-State Microbunching (SSMB) is emerging as a new concept for accelerator-based light sources to meet demands for high average power radiation at short wavelengths. The authors present findings from a proof-of-principle experiment that agree with theoretical expectations in multiple aspects, laying the foundation for the future realization of SSMB. [ABSTRACT FROM AUTHOR]

We have studied the stability of C59 anions as a function of time, from their formation on femtosecond timescales to their stabilization on second timescales and beyond, using a combination of theory and experiments. The C 59 − fragments were produced in collisions between C60 fullerene anions and neutral helium gas at a velocity of 90 km s−1 (corresponding to a collision energy of 166 eV in the center-of-mass frame). The fragments were then stored in a cryogenic ion beam storage ring at the DESIREE facility, where they were followed for up to 1 minute. Classical molecular dynamics simulations were used to determine the reaction cross section and the excitation energy distributions of the products formed in these collisions. We find that about 15% of the C 59 − ions initially stored in the ring are intact after about 100 ms and that this population then remains intact indefinitely. This means that C60 fullerenes exposed to energetic atoms and ions, such as stellar winds and shock waves, will produce stable, highly reactive products, like C59, that are fed into interstellar chemical reaction networks. [ABSTRACT FROM AUTHOR]

This paper addresses the design of beam position monitor (BPM) devices suitable for fourth-generation diffraction-limited X-ray storage rings. Detailed investigations of the electromagnetic (EM) phenomena occurring inside the component under various working conditions are carried out by considering different BPM EM models defined by their geometry and materials. Moving from a theoretical characterization of the common round geometry, rhomboidal structures are studied through a careful numerical analysis relying on advanced computer-aided tools. Several critical elements, such as wakefields, pick-up signal extraction, and trapped and propagating modes, are explored from the simulation point of view and from the experimental one, by deploying a manufactured microwave test bench, which is employed to measure the radio frequency behavior of a BPM prototype built at Elettra Sincrotrone Trieste. The aim of the proposed study is to identify a satisfactory tradeoff between achievable performance and practical realizability for BPM devices operating in last-generation light sources. [ABSTRACT FROM AUTHOR]

The infrared beamline at BESSY II storage ring was upgraded recently to extend the capabilities of infrared microscopy. The endstations available at the beamline are now facilitating improved characterization of molecules and materials at different length scales and time resolutions. Here, the current outline of the beamline is reported and an overview of the endstations available is given. In particular, the first results obtained by using a new microscope for nano-spectroscopy that was implemented are presented. The capabilities of the scattering-type near-field optical microscope (s-SNOM) are demonstrated by investigating cellulose microfibrils, representing nanoscopic objects of a hierarchical structure. It is shown that the s-SNOM coupled to the beamline allows imaging to be performed with a spatial resolution of less than 30 nm and infrared spectra to be collected from an effective volume of less than 30 nm x 30 nm x 12 nm. Potential steps for further optimization of the beamline performance are discussed. [ABSTRACT FROM AUTHOR]

Fourth-generation synchrotron storage rings represent a significant milestone in synchrotron technology, offering outstandingly bright and tightly focused X-ray beams for a wide range of scientific applications. However, due to their inherently tight magnetic lattices, these storage rings have posed critical challenges for accessing lower-energy radiation, such as infrared (IR) and THz. Here the first-ever IR beamline to be installed and to operate at a fourth-generation synchrotron storage ring is introduced. This work encompasses several notable advancements, including a thorough examination of the new IR source at Sirius, a detailed description of the radiation extraction scheme, and the successful validation of our optical concept through both measurements and simulations. This optimal optical setup has enabled us to achieve an exceptionally wide frequency range for our nanospectroscopy experiments. Through the utilization of synchrotron IR nanospectroscopy on biological and hard matter samples, the practicality and effectiveness of this beamline has been successfully demonstrated. The advantages of fourth-generation synchrotron IR sources, which can now operate with unparalleled stability as a result of the stringent requirements for producing low-emittance X-rays, are emphasized. [ABSTRACT FROM AUTHOR]

In the last decade nuclear reaction measurements using heavy ion storage rings became an important tool for nuclear astrophysics studies. The new CRYRING Array for Reaction MEasurements (CARME), recently commissioned at the low energy CRYRING@ESR storage ring (GSI/FAIR), is designed to take this novel approach one step further and perform direct nuclear reaction measurements at stellar energies, as well as indirect studies of nuclear properties of interest for nuclear astrophysics. CRYRING is unique worldwide in being able to store high quality, isotopically pure, radioactive beams produced in-flight at the low energies required for nuclear astrophysics. This paper describes the first in-beam reaction measurement with CARME at CRYRING, the first beam on (conventional) target measurement for FAIR Phase-0, and the data analysis approach required by this unprecedented, unique experimental approach. [ABSTRACT FROM AUTHOR]

Building reliable fast orbit feedback (FOFB) systems to offer high stability of the beam orbit becomes more challenging for the diffraction-limited storage ring due to the smaller beam size. The beam position measurement and control (BPMC) processor has been developed to streamline the FOFB system architecture by integrating BPM (Beam Position Monitor) electronics and an orbit feedback controller. This paper designs a hierarchical dual-ring network topology based on BPMC processors using parameters derived from the storage ring of the Hefei Advanced Light Facility. To reduce latency and prevent data transmission collisions, we propose a multi-forwarding communication scheme and a communication controller design in a field-programmable gate array. Experimental results verify that this topology operates reliably with the multi-forwarding scheme, providing an approximate communication latency as low as 17.336 μs to support the 30 kHz orbit feedback update rate. [ABSTRACT FROM AUTHOR]

In this paper, the magnetic structure of the storage ring for an X-ray source based on the effect of Compton backscattering and designed for use in the electron beam energy range from 35 to 120 MeV is investigated. For this storage ring, the results of calculating the dynamics of the electron beam are presented, and the effects of radiation damping, quantum excitation, laser damping, and intrabeam scattering are considered. The dynamic aperture and energy acceptance of this ring are discussed. The results of calculating the magnitude of the spectral brightness of X-ray radiation and its change over time are provided. [ABSTRACT FROM AUTHOR]

Considering the demand of users to achieve minimum emittance and thus the dynamic aperture shrink, it is consistently important to find an optimal scheme for injecting the beam with the maximum current to fill the acceptance. We present an on-axis injection scheme with designed elements of the injection system such as septum and pulsed sextupole magnet (PSM) in the 3.5 GeV storage ring. The on-axis injection with the pulsed sextupole magnet will allow frequent low-charge which will further improve the stability in the storage ring. A macroparticle beam of Gaussian distribution is used for simulating the injection process by the ELEGANT code. The multiturn injection has been used in the simulations of the injection process in the storage ring. By studying the theory of particle accumulation in each turn of the injection, we calculated the number of possible injection times. A PSM with the desired strength and suitable location can kick the injected beam into limited acceptance. In this study, the reason for the superiority of pulsed sextupole magnet in the injection system over pulsed quadrupole magnet (PQM) has been proposed. The injection system supplies a top-up mode in which the beam current is maintained high by frequent injections in the storage ring. Various errors such as misalignment, space-charge and mismatch are included to obtain realistic simulations of the injection process. Also, the emittance blow-up due to the mismatch errors at the moment of the injection in phase space is expressed. [ABSTRACT FROM AUTHOR]

As a representative of the fourth-generation light sources, the High Energy Photon Source (HEPS) in Beijing, China, utilizes a multi-bend achromat lattice to obtain an approximately 100 times emittance reduction compared with thirdgeneration light sources. New technologies bring new challenges to operate the storage ring. In order to meet the beam commissioning requirements of HEPS, a new framework for the development of high-level applications (HLAs) has been created. The key part of the new framework is a dual-layer physical module to facilitate the seamless fusion of physical simulation models with the real machine, allowing for fast switching between different simulation models to accommodate the various simulation scenarios. As a framework designed for development of physical applications, all variables are based on physical quantities. This allows physicists to analytically assess measurement parameters and optimize machine parameters in a more intuitive manner. To enhance both extensibility and adaptability, a modular design strategy is utilized, partitioning the entire framework into discrete modules in alignment with the requirements of HLA development. This strategy not only facilitates the independent development of each module but also minimizes inter-module coupling, thereby simplifying the maintenance and expansion of the entire framework. To simplify the development complexity, the design of the new framework is implemented using Python and is called Python-based Accelerator Physics Application Set (Pyapas). Taking advantage of Python's flexibility and robust library support, we are able to develop and iterate quickly, while also allowing for seamless integration with other scientific computing applications. HLAs for both the HEPS linac and booster have been successfully developed. During the beam commissioning process at the linac, Pyapas's ease of use and reliability have significantly reduced the time required for the beam commissioning operators. As a development framework for HLA designed for the new-generation light sources, Pyapas has the versatility to be employed with HEPS, as well as with other comparable light sources, due to its adaptability. [ABSTRACT FROM AUTHOR]

Spontaneous and photo-induced decay processes of HfF5− and WF5− molecular anions were investigated in the Double ElectroStatic Ion Ring ExpEriment (DESIREE). The observation of these reactions over long time scales (several tens of ms) was possible due to the cryogenic temperatures (13 K) and the extremely low residual gas pressure (∼10−14 mbar) of DESIREE. For photo-induced reactions, laser wavelengths in the range 240 to 450 nm were employed. Both anion species were found to undergo spontaneous decay via electron detachment or fragmentation. After some ms, radiative cooling processes were observed to lower the probability for further decay through these processes. Photo-induced reactions indicate the existence of an energy threshold for WF5− anions at about 3.5 eV, above which the neutralization yield increases strongly. By contrast, HfF5− ions exhibit essentially no enhanced production of neutrals upon photon interaction, even for the highest photon energy used in this experiment (∼5.2 eV). This suppression will be highly beneficial for the efficient detection, in accelerator mass spectrometry, of the extremely rare isotope 182Hf using the 182HfF5− anion while effectively reducing the interfering stable isobar 182W in the analyte ion 182WF5−. The radionuclide 182Hf is of great relevance in astrophysical environments as it constitutes a potential candidate to study the events of nucleosynthesis that may have taken place in the vicinity of the solar system several million years ago. [ABSTRACT FROM AUTHOR]

The unimolecular dissociation and infrared radiative cooling rates of cationic 1-hydroxypyrene (OHPyr+, C16H10O+) and 1-bromopyrene (BrPyr+, C16H9Br+) are measured using a cryogenic electrostatic ion beam storage ring. A novel numerical approach is developed to analyze the time dependence of the dissociation rate and to determine the absolute scaling of the radiative cooling rate coefficient. The model results show that radiative cooling competes with dissociation below the critical total vibrational energies Ec = 5.39(1) eV for OHPyr+ and 5.90(1) eV for BrPyr+. These critical energies and implications for radiative cooling dynamics are important for astrochemical models concerned with energy dissipation and molecular lifecycles. The methods presented extend the utility of storage ring experiments on astrophysically relevant ions. [ABSTRACT FROM AUTHOR]

Cross-sections and rate coefficients for rovibronic excitation of the CH+ ion by electron impact and dissociative recombination of CH+ with electrons are evaluated using a theoretical approach combining an R-matrix method and molecular quantum defect theory. The method has been developed and tested, comparing the theoretical results with the data from the recent Cryogenic Storage Ring experiment. The obtained cross-sections and rate coefficients evaluated for temperatures from 1 to 10 000 K could be used for plasma modelling in the interpretation of astrophysical observations and also in the technological applications where the molecular hydrocarbon plasma is present. [ABSTRACT FROM AUTHOR]

The past, current and planned future developments of X-ray imagers in the Photon-Science Detector Group at DESY-Hamburg is presented. the X-ray imagers are custom developed and tailored to the different X-ray sources in Hamburg, including the storage ring PETRA III/IV; the VUV-soft X-ray free electron laser FLASH, and the European Free-Electron Laser. Each source puts different requirements on the X-ray detectors, which is described in detail, together with the technical solutions implemented. [ABSTRACT FROM AUTHOR]

Young's double-slit interference experiments with undulator vortex radiation were conducted, focusing on photon-counting regime. To isolate the second harmonic radiation in the ultraviolet range emitted from the helical undulator and achieve successful counting measurements, an ultranarrow bandpass filter was utilized under an extremely low-current mode of the electron storage ring. It was observed that the photon spots on the detector, after passing through the double slits, appeared to be randomly distributed. However, upon integrating these photon spots, it was confirmed that interference fringes with characteristic features of optical vortices, such as dark and broken/distorted stripes in the center, were formed. The reproducibility of these interference fringes was confirmed by calculating the optical path difference for the optical vortex reaching the double slits, as well as the optical path difference resulting from normal double-slit interference. Consequently, these findings indicate that even in the state of a single photon, the radiation emitted spontaneously by a high-energy electron in spiral motion possesses the nature of an optical vortex, characterized by a spiral wavefront. [ABSTRACT FROM AUTHOR]

Experiments with polarized beams for electric dipole moment search in the NICA accelerator complex implies the design of additional bypass channels. Such alternative channels will make it possible to use NICA as a storage ring and collect enough statistical data. [ABSTRACT FROM AUTHOR]

The structure of a compact X-ray source based on inverse Compton scattering and the beam dynamics in the linac and the storage ring is considered. The features of collective effects in the storage rings of such installations are studied in compaаrison with fourth-generation SR sources. The thresholds of longitudinal microwave instability and transverse instability of coupled modes are calculated. [ABSTRACT FROM AUTHOR]

The dynamics of spin in external electromagnetic, gravitational, and axion fields is analyzed in the framework of the gravitoelectromagnetism approach in Einstein's general relativity theory. We consistently extend the recent studies from the flat Minkowski geometry to the curved spacetime manifolds, contributing to the discussion of the possible new role of a precessing spin as an "axion antenna" that can be used to detect the hypothetical axion-like dark matter. The formalism developed helps to clarify the subtle influence of the gravitational/inertial and axion fields in the ultra-sensitive high-energy spin experiments with charged particles and neutrons at accelerators and storage rings devoted to testing fundamental physical symmetries, including attempts to establish the nature of dark matter in the Universe. [ABSTRACT FROM AUTHOR]

In this Letter, we report on the concept and analysis of a low-emittance electron storage ring, in which the electron beams undergo an early-stage self-amplified spontaneous emission lasing process on a turn-by-turn basis. The lasing process for each pass through a long undulator in the ring is terminated when the radiated power is still negligible compared to the total synchrotron loss of each circulation, and the electron beams can be maintained in an equilibrium state that supports sustainable lasing. A self-consistent model is derived for evaluation of the properties of the electron beams, and a design with numerical modeling is presented that demonstrates the feasibility of generating short wavelength radiation at the kW power level. [ABSTRACT FROM AUTHOR]

The short wavelength operation of free-electron laser (FEL) oscillators is limited by the availability of high-reflectivity, thermally stable, and radiation-resistant FEL mirrors in the vacuum UV (VUV) wavelength. We report our recent work to extend the shortest lasing wavelength of the oscillator FEL to 168.6 nm using a storage ring FEL. This progress has been made possible by developing a new FEL configuration with substantially reduced undulator harmonic radiation on the FEL mirror, a thermally stable FEL optical cavity, and a new type of high-reflectivity fluoride-based multilayer coating with a protective capping layer. Using these fluoride-based mirrors, we have demonstrated storage ring FEL lasing from 168.6 to 179.7 nm with excellent beam stability. Employing this VUV FEL in Compton scattering, we have produced the first 120 MeV gamma rays at the High Intensity Gamma-ray Source (HIGS). Operating the HIGS in this new high-energy region will create many new opportunities for photonuclear physics research, in particular, the low-energy quantum chromodynamics research. [ABSTRACT FROM AUTHOR]

The advances in technology mainly concerning ion traps, storage rings, lasers, high-precision frequency measurements, detectors, and particle beams as well as advances in atom and ion manipulation have allowed for a considerable progress in the determination of fundamental parameters and quantities of radionuclides such as masses, electromagnetic moments, lifetimes and beta decay correlations. The main subjects covered by this topical collection are: high-precision mass measurements both with Penning traps and storage rings for neutrino physics, nuclear structure, astrophysics, and decay studies. Laser spectroscopy is applied for the determination of other ground state properties like spins, moments, and nuclear charge radii. Furthermore, results from decay studies of highly charged ions and reactions in storage rings are presented. [ABSTRACT FROM AUTHOR]

The past, current and planned future developments of X-ray imagers in the Photon-Science Detector Group at DESY-Hamburg is presented. the X-ray imagers are custom developed and tailored to the different X-ray sources in Hamburg, including the storage ring PETRA III/IV; the VUV-soft X-ray free electron laser FLASH, and the European Free-Electron Laser. Each source puts different requirements on the X-ray detectors, which is described in detail, together with the technical solutions implemented.

To steer and track electron motion in atoms, molecules, and nanostructures, light pulses with attosecond duration and high repetition rate are required. In this paper, we use the angular dispersion-induced microbunching scheme and a few-cycle laser within a straight section (a few meters) of a diffraction-limited storage ring to generate a coherent high-flux attosecond pulse in the water window region. Simulation results based on the Southern Advanced Photon Source indicate that the proposed method can generate a chirp-free Fourier transform limited pulse with a minimum duration of 50 as, a maximum repetition rate of a few MHz, and a maximum average flux of about 4.4 × 10 11 photons/s/1%Bw. [ABSTRACT FROM AUTHOR]

Coherent spin motion is a necessary condition to search for the electric dipole moment of charged particles in a storage ring. The first step to increase the spin coherence time is to turn on a radiofrequency cavity. The next step is to manipulate equilibrium energy levels associated with betatron orbit lengthening and nonlinear momentum compaction factor. Spin resonances act as additional sources of decoherence especially for a proton beam. [ABSTRACT FROM AUTHOR]

Many particle accelerators rely on maintaining low pressures to ensure efficient operation, minimize beam losses, and reduce radiation background. To ensure a beam lifetime of 1-20 hours for the Synchrotron-light for Experimental Science and Applications in the Middle East (SESAME) vacuum system, an ideal average dynamic pressure of 1×10-9 mbar was targeted. This pressure was intended to be maintained while running the accelerator at a current of 400 mA after a cumulative dose of 100 Ah. In this study, a MATLAB code was employed to develop a series of one-dimensional equations that simulate the behavior of the vacuum system within the SESAME storage ring. The proposed model was then compared with the results generated by the VACCALC software and the Particle Monte Carlo (TPMC) MOLFLOW code, establishing a comprehensive assessment framework. The collected data from the model was subsequently compared with the recorded static and dynamic pressure measurements obtained during more than 1000 Ah of beam conditioning at 2.5 GeV. In results, the projected and actual values of dynamic pressures exhibited a satisfactory degree of agreement across the investigated range of beam conditioning doses, with a consistency factor exceeding 2 after a 100 Ah dose. [ABSTRACT FROM AUTHOR]

The cool storage ring (CSR) external-target experiment (CEE) will be the first large-scale nuclear physics experiment at the Heavy Ion Research Facility in Lanzhou (HIRFL). The beam monitor, designed to measure the lateral position of each beam particle, will improve the precision of primary vertex reconstruction otherwise determined by the time projection chamber (TPC) and multi-wire drift chambers (MWDCs). The beam monitor mainly contains two gaseous ionization sub-detectors, each measuring one lateral coordinate of the beam. The design requirements include the spatial resolution of m, the two-particle separation capability of s, the rate capability of pps, and small material budget. It features novel front-end pixel chips for both charge sensing and readout functions. The first prototype, utilizing the common-purpose Topmetal-II-chips, has been developed and tested; the second one, deploying the custom-designed Topmetal-CEEv1 chips, is currently being assembled. In this paper we will present the detector specifications, design and test of the prototypes, in particular the charge sensing and readout chips. [ABSTRACT FROM AUTHOR]

The SAXSMAT beamline P62 (Small-Angle X-ray Scattering beamline for Materials Research) is a new beamline at the high-energy storage ring PETRA III at DESY. This beamline is dedicated to combined small- and wide-angle X-ray scattering (SAXS/WAXS) techniques for both soft and hard condensed matter systems. It works mainly in transmission geometry. The beamline covers an energy range from 3.5 keV to 35.0 keV, which fulfills the requirements of the user community to perform anomalous scattering experiments. Mirrors are used to reduce the intensity of higher harmonics. Furthermore, the mirrors and 2D compound refracting lenses can focus the beam down to a few micrometres at the sample position. This option with the high photon flux enables also SAXS/WAXS tensor tomography experiments to be performed at this new beamline in a relatively short time. The first SAXS/ WAXS pattern was collected in August 2021, while the first user experiment was carried out two months later. Since January 2022 the beamline has been in regular user operation mode. In this paper the beamline optics and the SAXS/ WAXS instrument are described and two examples are briefly shown. [ABSTRACT FROM AUTHOR]

It is proposed to use the photoelectric effect on inner s shells of the 229Th atom to more accurately determine the energy of its 8.3-eV isomer. The calculation has been performed using the Feinberg–Migdal shaking theory, which gives the probability of the formation of the isomer up to on the K shell. As a result, two lines separated by the energy of the isomer has been predicted in the spectrum of photoelectrons. Other applications of the method to study the properties of the isomer, including that through shaking at the formation of radioactive beams at storage rings, have also been discussed. Furthermore, the experimental detection of the effect will make it possible to determine more accurately its partial lifetime. [ABSTRACT FROM AUTHOR]

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Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Traditional off-axis injection becomes inadequate in diffraction limited storage ring (DLSR) for its small dynamic aperture (DA). On-axis injection with thin septum could solve the problem. This paper focuses on the theoretical calculation, field simulation, and measurement of thin septum magnets. The scheme of eddycurrent type thin septum magnets (the thinnest portion is with the thickness of 0.9 mm) was adopted with laminated silicon steel sheets as the magnet core. The simulation of main field, stray field along the beam trajectory, the leakage field decayed over 1 millisecond time was carried out within Opera 2D/3D. Field measurement and analysis of thin septum magnets also has been conducted comprehensively. The results meet requirements, and the work laid a foundation for injection technology of an advanced light source. [ABSTRACT FROM AUTHOR]