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The coherence properties of the beam provided at the CoSAXS beamline at the MAX IV Laboratory are determined experimentally using multi-mode ptychography. The coherent fraction of the beam is then used for a proof-of-concept XPCS measurement, illustrating the beamline’s capabilities., The CoSAXS beamline at the MAX IV Laboratory is a modern multi-purpose (coherent) small-angle X-ray scattering (CoSAXS) instrument, designed to provide intense and optionally coherent illumination at the sample position, enabling coherent imaging and speckle contrast techniques. X-ray tracing simulations used to design the beamline optics have predicted a total photon flux of 1012–1013 photons s−1 and a degree of coherence of up to 10% at 7.1 keV. The normalized degree of coherence and the coherent flux of this instrument were experimentally determined using the separability of a ptychographic reconstruction into multiple mutually incoherent modes and thus the Coherence in the name CoSAXS was verified. How the beamline can be used both for coherent imaging and XPCS measurements, which both heavily rely on the degree of coherence of the beam, was demonstrated. These results are the first experimental quantification of coherence properties in a SAXS instrument at a fourth-generation synchrotron light source.

On 25 August 2020, the ESRF succeeded in opening its new Extremely Brilliant Source (EBS), a first-of-its-kind, new generation of high-energy synchrotron light source, to the international scientif...

Ptychographic X-ray computed tomography is a quantitative three-dimensional imaging technique offered to users of multiple synchrotron radiation sources. Its dependence on the coherent fraction of the available X-ray beam makes it perfectly suited to diffraction-limited storage rings. Although MAX IV is the first, and so far only, operating fourth-generation synchrotron light source, none of its experimental stations is currently set up to offer this technique to its users. The first ptychographic X-ray computed tomography experiment has therefore been performed on the NanoMAX beamline. From the results, information was gained about the current limitations of the experimental setup and where attention should be focused for improvement. The extracted parameters in terms of scanning speed, size of the imaged volume and achieved resolutions should provide a baseline for future users designing nano-tomography experiments on the NanoMAX beamline.

We study magnetic lattice and optimize parameters for the fourth generation light source SKIF (Russian acronym of Siberian Circular Photon Source) to be built in Novosibirsk. We consider several lattice cells to achieve both low emittance and large dynamic aperture. The resulting lattice provides the natural emittance of the electron beam of 75 pm for the beam energy of 3 GeV and the orbit circumference of 476 m. Only two families of chromatic sextupoles give the dynamic aperture and energy bandwidth enough for both good beam lifetime and simple effective injection.

Radiation-induced color centers locally produced in lithium fluoride (LiF) are successfully used for radiation detectors. LiF detectors for extreme ultraviolet radiation, soft and hard X-rays, based on photoluminescence from aggregate electronic defects, are currently under development for imaging applications with laboratory radiation sources, as well as large-scale facilities. Among the peculiarities of LiF-based detectors, noteworthy ones are their very high intrinsic spatial resolution across a large field of view, wide dynamic range, and versatility. LiF crystals irradiated with a monochromatic 8 keV X-ray beam at KIT synchrotron light source (Karlsruhe, Germany) and with the broadband white beam spectrum of the synchrotron bending magnet have been investigated by optical spectroscopy, laser scanning confocal microscopy in fluorescence mode, and confocal Raman micro-spectroscopy. The 3D reconstruction of the distributions of the color centers induced by the X-rays has been performed with both confocal techniques. The combination of the LiF crystal capability to register volumetric X-ray mapping with the optical sectioning operations of the confocal techniques has allowed performing 3D reconstructions of the X-ray colored volumes and it could provide advanced tools for 3D X-ray detection.

The capability of providing full-charge bunches has become an important requirement for quite a few boosters used in ultralow-emittance storage rings based synchrotron light sources. The transverse single-bunch instabilities may limit the single-bunch charge in these type of boosters. The relatively weak synchrotron radiation damping makes the bunch more unstable at the injection energy than at the extraction energy. Therefore, studies of the transverse single-bunch instabilities are carried out first at the injection energy, with the chromaticity varied, to understand how the threshold changes accordingly. Our studies show that the single-bunch threshold current tends to drop when the chromaticity becomes nonzero at the injection energy of the used booster lattice. The corresponding simulation results are presented and analyzed. Furthermore, the transverse single-bunch instabilities during the energy ramping process are also studied.

Detectors made from sub-micron-sized bridges of the high- ${T}_{c}$ superconductor Y–Ba–Cu–O have unique properties useful for the detection of THz radiation, namely evidence of a detector response with an additional sensitivity to the direction of the electric field of short THz pulses when used without a transport current in the so-called “zero-bias” regime. In order to examine the influence of the antenna design on the detector response, we have conducted electromagnetic simulations and performed experiments at a synchrotron light source and with a photomixing setup as sources for short THz pulses. In this paper, we evaluate a narrow-band double-slot antenna as well as a broadband log-spiral antenna design.

Synchrotrons and modern FEL light sources operate with bunch repetition rates in the MHz range. The profile of the electron beam inside the accelerator can be characterized with indirect experimental techniques where linear array detectors are employed to measure the emitted synchrotron radiation or the spectrum of a near-IR laser. To improve the performance of modern beam diagnostics we have developed KALYPSO, a detector system operating with a continuous frame rate of up to 2.7 MHz. To facilitate the integration in different experiments, a modular architecture has been adopted. Different semiconductor micro-strip sensors can be connected to front-end ASICs to optimize the quantum efficiency at different photon energies, ranging from visible light up to near-IR. The front-end electronics are integrated within an heterogeneous DAQ consisting of FPGAs and GPUs, which allows scientists to implement real-time data processing algorithms. The current version of the detector is in operation at the KARA synchrotron light source and at the European XFEL. In this contribution we present the detector architecture, the performance results and the on-going technical developments.

Cryogenically-cooled permanent-magnet-based undulators (CPMUs) have been developed and built at several places around the world in the last decade. They currently operate successfully at many synchrotron radiation facilities, and they are planned as radiators in compact light sources based on laser plasma accelerated electrons. CPMUs have become the undulators of choice at medium energy storage rings. In the past few years, the performance of CPMUs has been brought closer to the physical limit; future incremental improvements will allow the limit to be reached. Superconducting undulators (SCUs), however, despite having a longer history than CPMUs, had not attracted the same level of investment. SCU programs have only relatively recently been given significant funding priority at the Advanced Photon Source (APS). The investment at APS has resulted in the construction of the specialized SCU facility, and in the design and fabrication of several SCUs which are currently operating on the APS ring. KIT invested in the development of a cold vacuum chamber (COLDDIAG) for beam heat load studies, in a precise horizontal conduction cooled magnetic characterization facility as well as in a strong collaboration with the industrial partner Bilfinger Noell. This led to the production of two undulators successfully tested in the KIT synchrotron light source. The combination of mature CPMU technology and developing SCU technology will provide significant flexibility in the choice of advanced undulators for new and upgraded light source facilities. This review paper covers the status of operations and development of CPMUs and SCUs.

Physical review accelerators and beams 24(11), 111301 (2021). doi:10.1103/PhysRevAccelBeams.24.111301, The present state of progress in laser wakefield acceleration encourages considering it as a practical alternative to conventional particle accelerators. A promising application would be to use a laser plasma accelerator as an injector for a synchrotron light source. The injector could deliver low charge ($\sim 100$~pC) beams to top up the storage ring and reduce the load on the chain of conventional injectors. Yet, the energy spread and jitter of the laser plasma beam pose a significant difficulty for an efficient injection. In this paper we propose a design of a prototype injector to deliver 500 MeV low-intensity electron bunches to the DESY-II electron synchrotron. The design utilizes presently available conventional accelerator technology, such as a chicane and an X-band radio frequency cavity, to reduce the energy spread and jitter of the electron beam down to a sub-per-mille level., Published by American Physical Society, College Park, MD

The first synchrotron light source in Thailand was established in 1996, Siam Photon Source is operated and developed the capability of the facility to increase the energy up to 1.2 GeV by Synchrotron Light Research Institute (SLRI). Many users from both inside and outside the country come to use the synchrotron light which is increasing steadily. As a result, Siam Photon Source II at 3 GeV project is taken place in 2019. The Hard X-ray absorption spectroscopy has been planned to support which two consideration designs of the X-ray energy range are 2.4 – 40 keV at the first and 4 – 35 keV at the second. The scattering synchrotron radiation can occur from the optical components in the beamline. The radiation must be controlled to be safe for the utilization of synchrotron radiation in which the radiation shielding design is taken into account. This work aimed to compare the first and second HXAS beamline shielding designs to evaluate the dose distribution to prevent the radiation scattering. The dose calculation was performed by STAC 8 program, therefore, estimate the radiation dose level at the surface outside of the beamline both optic hutch and experimental hutch. The results of the two design indicated that dose distributions with the scattering angle were below the design criteria at 0.1 µSv/h. The optic hutch shielding wall for the first design is below the second design while the experimental hutch shielding wall for the first design is higher than the second design.

Generation of extremely bright, coherent synchrotron radiation in a short wavelength range is of remarkable interest in the synchrotron light source community. In this paper, a novel technique is adopted to produce coherent radiation, which uses an angular dispersion mechanism to enhance the microbunching of electrons by introducing a slight energy modulation in the long straight section of the storage ring. For this purpose, a lattice design of an extreme low emittance storage ring with 3.5 GeV energy is presented in this paper, which employs a higher-order achromat concept. We show the design results of the multibend achromat lattice with an emittance of 20 pm rad and a circumference of 900 m. Numerical simulation results demonstrate that this angular dispersion-induced microbunching scheme can be used to generate coherent radiation near the soft x-ray region, the repetition rate can reach 10 kHz, and the spectral brightness can reach $2.3\ifmmode\times\else\texttimes\fi{}{10}^{24}\text{ }\text{ }\mathrm{photons}\text{ }{\mathrm{s}}^{\ensuremath{-}1}\text{ }{\mathrm{mm}}^{\ensuremath{-}2}\text{ }{\mathrm{mrad}}^{\ensuremath{-}2}$ ${(0.1%\text{ }\text{ }\mathrm{bandwidth})}^{\ensuremath{-}1}$.

Optical vortices have the main features of helical wavefronts and spiral phase structures, and carry orbital angular momentum. This special structure of visible light has been produced and studied for various applications. These notable characteristics of photons were also tested in the extreme-ultraviolet and X-ray regimes. In this article, we simulate the use of a simple afterburner configuration by directly adding helical undulators after the SASE undulators with the Shanghai Soft X-ray FEL to generate high intensity X-ray vortices with wavelengths $$\sim 1\,{\hbox {nm}}$$ . Compared to other methods, this approach is easier to implement, cost-effective, and more efficient.

We report the observation of quantum interference between electron wave packets launched from the inner-shell $4d$ orbital of the Xe atom. Using pairs of femtosecond radiation wave packets from a synchrotron light source, we obtain time-domain interferograms for the inner-shell excitations. This approach enables the experimental verification and control of the quantum interference between the electron wave packets. Furthermore, the femtosecond Auger decay of the inner-shell excited state is tracked. To the best of our knowledge, this is the first observation of wave packet interference in an atomic inner-shell process, and also the first time-resolved experiment on few-femtosecond Auger decay using a synchrotron light source.

We present a lattice design and beam dynamics analysis for a 4 GeV low-emittance, high-brilliance synchrotron light source. The lattice consisted of 26 six-bend achromats with 26 long and 26 short straight sections. We present the design results for a hybrid multi-bend achromat (HMBA) lattice with a natural emittance of 168 pm and circumference of 729.3 m. Each cell had 4 longitudinal gradient bendings, 2 combined bendings, 14 quadrupoles, and 2 families of sextupoles. The lattice was designed to be flexible to provide both nonzero and zero dispersion functions in the long straight section. The two straight sections in each cell had lengths of 5.6 and 1.2 m. To ensure sufficient injection, we optimized the design lattice and dynamic aperture. We investigated the dynamic aperture in the lattice with machine errors, and the results showed that the lattice design provides sufficient dynamic aperture after COD correction for beam injection. We present the results of an injection scheme that demonstrates the space in the injection section and the particle motions of the injected beam. We also present the results of beam tracking after the beam injection to examine the characteristics of the beam injection. The designed HMBA lattice was well optimized in terms of the beam parameters and brilliance as an intermediate light source at 4 GeV and a circumference of 729.3 m.

This paper outlines the results of investigations into the effects of radiation damage in the mini-MALTA depleted monolithic pixel sensor prototype. Measurements were carried out at Diamond Light Source using a micro-focus X-ray beam, which scanned across the surface of the device in 2 μ m steps. This allowed the in-pixel photon response to be measured directly with high statistics. Three pixel design variations were considered: one with the standard continuous n − layer layout and front-end, and extra deep p-well and n − gap designs with a modified front-end. Five chips were measured: one unirradiated, one neutron irradiated, and three proton irradiated. The standard design showed a decrease of 12% in pixel response after irradiation to 1e15 n eq ∕ cm 2 . For the two new designs the pixel response did not decrease significantly after irradiation. A decrease of pixel response at high biasing voltages was observed. The charge sharing in the chip was quantified and found to be in agreement with expectations.

Detector prototypes are commonly characterised in testbeams, either using charged particles or X-rays. Charged particles are used to quantify detector performance in terms of absolute efficiency, while X-rays can provide additional information about the detector structure. This paper presents an alternative approach to calculating charged particle efficiencies, using the results of an X-ray testbeam of the mini-MALTA CMOS prototype at Diamond Light Source, and additional laboratory measurements. Results are presented for an unirradiated and an irradiated sample and compared to the results of charged particle testbeams at SPS and ELSA. The extrapolated efficiencies are in agreement with the measured values. Additionally, the extrapolated efficiency maps provide more insight about the location of the pixel inefficiencies, due to the better spatial resolution of the X-ray testbeam.

Alba is a 3 GeV, 3 nm emittance synchrotron light source located near Barcelona (www.cells.es). Eight beamlines are in operation and three more are being built. In what follows, we will describe four examples of recent scientific results involving imaging in real space. Mistral is a soft X-ray microscope installed downstream from a bending magnet source devoted to cryo-tomography, and also to material science and magnetism. Circular polarized radiation is obtained by extracting the beam above or below the orbit plane with ancillary slits. Circe is a photoemission beamline with two end stations, one of them a PEEM/LEEM microscope specializing in magnetic imaging, and Miras is an infrared beamline equipped with a microscope for biosciences and material science.

Fast Orbit Feedback System (FOFB) can be installed in a synchrotron light source to eliminate undesired disturbances and to improve the stability of beam orbit. The design and implementation of an accurate and reliable Fast Corrector Power Supply (FCPS) is essential to realize the effectiveness and availability of the FOFB. A reliability assessment for the FCPSs in the FOFB of Taiwan Photon Source (TPS) considering MOSFETs’ temperatures is represented in this paper. The FCPS is composed of a full-bridge topology and a low-pass filter. A Hybrid Pulse Width Modulation (HPWM) requiring two MOSFETs in the full-bridge circuit to be operated at high frequency and the other two be operated at the output frequency is adopted to control the implemented FCPS. Due the characteristic of HPWM, the conduction loss and switching loss of each MOSFET in the FCPS is not same. Two of the MOSFETs in the full-bridge circuit will suffer higher temperatures and therefore the circuit reliability of FCPS is reduced. A Modified PWM Scheme (MPWMS) designed to average MOSFETs’ temperatures and to improve circuit reliability is proposed in this paper. Experimental results measure the MOSFETs’ temperatures of FCPS controlled by the HPWM and the proposed MPWMS. The reliability indices under different PWM controls are then assessed. From the experimental results, it can be observed that the reliability of FCPS using the proposed MPWMS can be improved because the MOSFETs’ temperatures are closer. Since the reliability of FCPS can be enhanced, the availability of FOFB can also be improved.

We present a detailed study using the skew quadrupoles in the Canadian Light Source storage ring lattice to control the parameters of a coupled lattice. We calculate the six-dimensional beam envelop matrix and use it to produce a variety of objective functions for optimization using the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm. MOPSO produces a number of skew quadrupole configurations that we apply to the storage ring. We use the X-ray synchrotron radiation diagnostic beamline to image the beam and we make measurements of the vertical dispersion and beam lifetime. We observe satisfactory agreement between the measurements and simulations. These methods can be used to adjust phase space coupling in a rational way and have applications to fine-tuning the vertical emittance and Touschek lifetime and measuring the gas scattering lifetime.

In this work, the preliminary design of an electron linear particle accelerator (eLINAC) capable ofdelivering a beam within an energy range of 5 to 100 MeV using the S-band acceleration frequencyis presented. At its peak energy, it can be used as an injector for a synchrotron light source,independent free electron laser, or to generate neutrons. The eLinac will be separated into threebeam lines to deliver electron beams at dierent energies permitting the possibility of industrialapplications such as food irradiation, medical use, and national security.

SESAME (Synchrotron-light for Experimental Science and Application in the Middle East) is a “third-generation” synchrotron light source. The Middle East’s first major international research centre, established as cooperative venture by the scientists and governments of the region, is situated in Jordan. On the basis of the agreement signed between INFN and SESAME, our collaboration has designed and is building a Fluorescence Detector System based on 64 SDDs, each having a 9 mm 2 non-collimated sensitive area, realized with eight monolithic arrays for a total collimated sensitive area of 499 mm 2 . The instrument will be used at the beamline dedicated to x-ray absorption spectroscopy in the energy range 3–30 keV with the capability of reaching a maximum counting rate of at least 3.2 Mcps. The energy resolution required for this application is below 150 eV FWHM @5.9 keV. We plan to have the system completely operative by July 2018. We report on the main building blocks of this system, dedicated to SESAME, and describe the experimental performances measured in the lab and on the XAFS beamline of ELETTRA Sincrotrone Trieste, Italy. In the very first tests the system was successfully operated up to 8 Mcounts/s. The energy resolution below 150 eV @5.9 keV was measured using a 1 . 6 μ s peaking time with the detector cooled to 10 °C.

In this paper, we investigate a lattice design for an ultra-low emittance storage ring with intermediate energy of 3 GeV and circumference of 576 m. We present the design results for a seven-band achromat lattice with the natural emittance of 90 pm-rad. The base line is based on 20 straight sections with the length of 6 m. The minimum distance between different magnets is 10 cm and it has been tried to keep the lattice structure as simple as possible. The brilliance of radiated synchrotron radiation from a 2.24 m In-vacuum undulator installed in the lattice is 4 × 10 21 photons ∕ s mm 2 mm 2 mrad 2 0 . 1 % BW . We will address the challenging points of designed ultra-low emittance storage ring lattice such as strong nonlinearity and collective effects. The dynamic aperture of the lattice is comparatively sufficient for off-axis injection and the lifetime is relatively large without using any harmonic cavity. Since the proposed lattice structure in some aspects is similar to MAX IV storage ring, we will make some comparison between two lattices in different sections.

The National Synchrotron Light Source (NSLS) ceased operation in September 2014 and was succeeded by NSLS-II. There were four in-vacuum undulators (IVUs) in operation at NSLS. The most recently constructed IVU for NSLS was the mini-gap undulator (MGU-X25, to be renamed IVU18 for NSLS-II), which was constructed in 2006. This device was selected to be reused for the New York Structural Biology Consortium Microdiffraction beamline at NSLS-II. At the time of construction, IVU18 was a state-of-the-art undulator designed to be operated as a cryogenic permanent-magnet undulator. Due to the more stringent field quality and impedance requirements of the NSLS-II ring, the transition region was redesigned. The control system was also updated to NSLS-II specifications. This paper reports the details of the IVU18 refurbishment activities including additional magnetic measurement and tuning.

High Energy Accelerator Research Organization (KEK [1]) is a world class accelerator-based research laboratory. The field of its scientific interests spreads widely from the study of fundamental properties of matter, particle physics, nuclear physics to materials science, life science, technical researches, and industrial applications. Research outcomes from the laboratory achieved making use of high-energy particle beams and synchrotron radiation. Two synchrotron facilities of KEK, the Photon Factory (PF) ring and the Photon Factory Advanced Ring (PF-AR) are the second biggest synchrotron light source in Japan. A very wide range of the radiated light, from visible light to X-ray, is provided for a variety of materials science, biology, and life science [2]. KEK strives to work closely with national and international research institutions, promoting collaborative research activities. Advanced research and facilities provision are key factors to be at the frontier of the accelerator science. In this review I am going to discuss KEK overall accelerator-based science, and to consider light sources research and development. The state of arts of the current projects with respect to the elementary particles physics in the external electromagnetic fields is also stressed here.

13th International Conference on Synchrotron Radiation Instrumentation, SRI2018, Taipei, Taiwan, 10 Jun 2018 - 15 Jun 2018; AIP conference proceedings 2054(1), 030002 (2019). doi:10.1063/1.5084565, At DESY the Synchrotron Light Source PETRA III offers scientists outstanding opportunities for experiments with hard X-rays of exceptionally high brilliance since 2009. Research activities have been started to upgrade PETRA III to the ultra-low emittance source PETRA IV, which will be diffraction limited up to the hard X-ray range. Therefore the future light source PETRA IV will be ideal for 3D X-ray microscopy of biological, chemical, and physical processes under realistic conditions at length scales from atomic dimensions to millimeters. The lattice design is aiming for a horizontal emittance in the range between 10 pm rad and 30 pm rad at a beam energy of 6 GeV. Presently, two different approaches are considered for the lattice design: a design based on a hybrid multibend achromat with an interleaved sextupole configuration based on the ESRF-EBS design, and a lattice with a double non-interleaved sextupole configuration. The current status of the design activities is reported including the injector and several technical aspects., Published by AIP, Melville, NY

Generation of coherent radiation pulses is of remarkable interest in the synchrotron light source community. A novel technique has been proposed to produce temporal coherent radiation in ref. [1]. In this scheme, an oblique incidence seed laser is utilized to introduce an angular modulation which is converted to microbunching by an angular dispersion section. In this paper, a specific design of the angular dispersion section is given to realize the coupling between transverse and longitudinal directions which satisfied the microbunching requirements of this technique. Numerical simulation results demonstrate that this lattice can be used to enhance the bunching factor at very high harmonics of the seed laser. The lattice structure has good flexibility, the elements of the transport matrix related to microbunching can be easily adjusted, and the beta function in the radiator can be simply optimized by adjusting the magnets of the transport line.

Transverse coupled bunch instability (TCBI) is a major concern at high beam current operations at all synchrotron light sources. Techniques for the mitigation of TCBI include higher order mode tuning of RF cavities, optimization of vacuum chamber designs, increasing the damping rate of beam oscillations, optimization of betatron tune values, and multi-bunch feedback systems. Due to uncertainties, time-variation, and disturbances, the dynamic behavior of accelerators requires further tuning of beam parameters beyond theory-based set points for minimizing the transverse coupled bunch mode (TCBM) instability. In this work, an artificial neural network (ANN) based system is developed to minimize average TCBM levels in the Indus-2 synchrotron light source at the Raja Ramanna Centre for Advanced Technology in Indore, India. The ANN is trained based on various TCBM measurements collected at the Indus-2 for various values of betatron tune and chromaticity in order to learn how to map beam measurements directly to parameters such as optimal betatron tunes and chromaticity values that are sent to a beam feedback control system. The ANN takes as input real-time beam data and is coupled to a feedback controller, thereby creating an adaptive feedback that is able to adjust in real time to variation of the accelerator and beam. We provide a detailed overview of our approach as well as experimental results in which the ANN-guided feedback approach increases the operational beam current of Indus-2 from a limit of ∼170 mA up to ∼230 mA within ∼21 min. We believe that this general method can be useful for a wide range of synchrotron sources operating at high bunch currents.

HEPS-BPIX3 is the third prototype of a single-photon counting pixel detector with 1.4 million pixels developed for applications using synchrotron light sources. It follows the previous prototypes with a pixel size of 150 μ m × 150 μ m and frame rate up to 1.2 kHz at 20-bit dynamic range. We started to upgrade it with the through silicon via (TSV) process to reduce the insensitive gap between modules. The TSV process drills vias at the pads of the readout chip, and makes connections between the front and back sides. The redistribution layer (RDL) and bump bonding are performed at the bottom of readout chip to connect the control, readout signals and power supplies to the PCB. By using this so-called three-dimensional (3D) integration techniques, the insensitive area of the module is reduced from 26.3% to 11.8%. The assembled modules have been tested with X-ray and synchrotron light source, and the results show that the readout chips work well following the TSV process without any measurable performance degradation.

The Iranian Light Source Facility is a fourth-generation low emittance synchrotron light source under development in Iran. The design and in-house fabrication of RF cavities are key elements of this project. The choice of 100 MHz capacity loaded RF cavities offers many advantages compared to other cavity types due to a simpler geometry, ease of fabrication, and lower costs for manufacturing and RF power system development. Here we present comprehensive simulation studies of these accelerating RF cavities. This includes electromagnetic, mechanical, and thermal calculations. In addition, in the electromagnetic design section, discussions of higher-order modes, their impact on beam instabilities during machine operation and beam loading effects are addressed. Finally, thermomechanical simulation results are presented. The fabrication of a 100 MHz capacity-loaded cavity has started based on the design presented in this article.

An insertion device (ID) is a crucial component in a third-generation synchrotron light source, which produces highly brilliant, forward-directed, and quasi-monochromatic radiation over a broad energy range. The Taiwan Photon Source (TPS) project involves building another synchrotron light source with increased electron energy. In phase I of TPS, seven in-vacuum undulators with magnetic period 22 mm (IU22) were installed; commissioning is in process. The control system for IU22 is based on an EPICS framework. The main control components include motors with encoders for gap adjustment, trimming power supplies for corrector magnets, ion pumps and Bayard-Alpert gauges for vacuum systems, temperature sensors for ID baking, and an interlock system (limit switches, emergency button) for safety. The design and implementation of the IU22 control system are summarized in this report.

The 3GeV SPEAR3 synchrotron light source operates in top-up injection mode with up to 500 mA circulating in the storage ring (equivalently 392 nC). Each injection pulse contains 40–80 pC producing a contrast ratio between total stored charge and injected charge of about 6500:1. In order to study transient injected beam dynamics during user operations, it is desirable to optically image the injected pulse in the presence of the bright stored beam. In the present work this is done by imaging the visible component of the synchrotron radiation onto a digital micro-mirror-array device (DMD), which is then used as an optical mask to block out light from the bright central core of the stored beam. The physical masking, together with an asynchronously-gated, ICCD imaging camera, makes it possible to observe the weak injected beam component on a turn-by-turn basis. The DMD optical masking system works similar to a classical solar coronagraph but has some distinct practical advantages: i.e. rapid adaption to changes in the shape of the stored beam, a high extinction ratio for unwanted light and minimum scattering from the primary beam into the secondary optics. In this paper we describe the DMD masking method, features of the high dynamic range point spread function for the SPEAR3 optical beam line and measurements of the injected beam in the presence of the stored beam.

The tolerances for the alignment of the magnets in the girders of the next machine of the Brazilian Synchrotron Light Laboratory (LNLS), Sirius, are as small as 40 µm for translations and 0.2 mrad for rotations. Therefore, a novel approach to the well-known vibrating wire technique has been developed and tested for the precise fiducialization of magnets. The alignment bench consists of four commercial linear stages, a stretched wire, a commercial lock-in amplifier working with phase-locked loop (PLL), a coordinate measuring machine (CMM) and a vibration sensor for the wire. This novel sensor has been designed for a larger linear region of operation. For the mechanical metrology step of the fiducialization of quadrupoles an innovative technique, using the vision system of the CMM, is presented. While the work with pitch and yaw orientations is still ongoing with promising partial results, the system already presents an uncertainty level below 10 µm for translational alignment.

Facilities with a synchrotron light source at present utilize both vacuum-tube and solid-state RF sources to accelerate an electron beam, thanks to the rapid development of semiconductor technology. In NSRRC, a retired 500-MHz 100-kW klystron-based RF transmitter and a newly developed 80-kW solid-state RF transmitter became available for experimental study. We proposed the usage of a 3-dB waveguide hybrid coupler to combine these two heterogeneous RF sources to provide twice the RF-power of each alone. The intrinsic difference in RF properties of these two RF-power sources seen by the 3-dB hybrid coupler is compensated with an analogue low-level feedback system that locks the klystron side to the solid-state RF source side for a quasi-equal power level and a quadrature phase offset to obtain the greatest efficiency of the combination. In this manner, we demonstrated an efficiency up to 98.3% for combined RF-power 140 kW measured at the target port of a 3-dB waveguide hybrid coupler; the dummy load after the non-target port received negligible power within the full power range. The robustness to a power imbalance between these two RF-power sources was studied theoretically and experimentally; the efficiency of the RF-power combination was maintained greater than 90% for an available power ratio of these two RF sources up to 3 or phase error within ± 45°. The results demonstrate an economical power-combination scheme for heterogeneous RF-power sources with high tolerance of imbalance for a symmetric power combiner. The usage of an asymmetric power combiner is foreseen to extend the imbalance tolerance.

This paper discusses improvements made to the fast orbit feedback (FOFB) system at NSLS-II in 2019. We first characterized the system by measuring the transfer function and the closed-loop gain of the system. We also constructed a model to predict the performance, which was based on physical behaviors. After finding and fixing the sources of the latency, we improved the closed-loop gain’s bandwidth from 250 Hz to 400 Hz in the horizontal plane and 250 Hz to 300 Hz in the vertical plane. The orbit beam instability improved by 30% and 10% in the horizontal and vertical planes, respectively.

A fast kicker is a significant component for on-axis injection of the new generation synchrotron light source with ultralow emittance. The Hefei Advanced Light Facility (HALF) plans to be a fourth-generation diffraction limited storage ring in the future. The preliminary research work is proceeding smoothly. On-axis longitudinal injection scheme is under consideration for the beam accumulation and has not yet been decided. This paper mainly introduces the development of a stripline kicker optimized for this injection scheme. The kicker, combined with a high-voltage pulse generator, can provide a deflection field for the injected bunch and making it completely transparent to circulating bunches without disturbing them. The structure was simulated by CST. The design results were judged by S-parameters and TDR. The S-parameters of the kicker were measured by a network analyzer, and the reliability of the simulation results was verified by comparing the measured and simulated results. The prototype was tested with a high-voltage pulse generator, and the change of the pulse in the prototype was obtained.

A low-frequency quarter-wave superconducting β = 1 structure has been proposed as a main accelerating cavity for the newly planned storage ring light source with ultra-low emittance. In the development of High Energy Photon Source, a 6 GeV diffraction-limited light source at the Institute of High Energy Physics, a compact 166.6 MHz proof-of-principle cavity was designed. By optimizing its geometry, the cavity’s mechanical properties have been significantly improved with a focus on stress, pressure sensitivity, Lorentz-force detuning, microphonics and tuning capabilities. The cavity was later fabricated, post-processed and tested in a vertical manner at cryogenic temperatures. High peak electromagnetic fields have been achieved with an excellent cryogenic performance, largely exceeding the design goal and project specifications. In addition, the measured mechanical parameters are in good accordance with simulation results. Small Lorentz coefficients and low pressure sensitivities were measured during the tests. This constitutes the first demonstration of a solid low-frequency β = 1 superconducting cavity design with compact geometry and favorable mechanical properties.

At many storage rings for synchrotron light production there is demand for serving both high-flux and timing users simultaneously. Today this is most commonly achieved by operating inhomogeneous fill patterns, but this is not preferable for rings that employ passive harmonic cavities to damp instabilities and increase Touschek lifetime. For these rings, inhomogeneous fill patterns could severely reduce the effect of the harmonic cavities. It is therefore of interest to develop methods to serve high-flux and timing users simultaneously without requiring gaps in the fill pattern. One such method is pseudo-single-bunch (PSB), where one bunch in the bunch train is kicked onto another orbit by a fast stripline kicker. The light emitted from the kicked bunch can then be separated by an aperture in the beamline. Due to recent developments in fast kicker design, PSB operation in multibunch mode is within reach for rings that operate with a 100 MHz RF system, such as the MAX IV and Solaris storage rings. This paper describes machine requirements and resulting performance for such a mode at the MAX IV 1.5 GeV storage ring. A solution for serving all beamlines is discussed as well as the consequences of beamline design and operation in the soft X-ray energy range.

In the field of the high injection rate X-ray meterage, currently there are no national standards in China, which are urgently needed in areas such as inertial confinement fusion diagnosis and aerospace observation. Globally, many metrology laboratories have developed their own meterage standards based on Cryogenic radiometers. And one soft X-ray cryogenic radiometer has been installed at 4B7B experiment station on Beijing Synchrotron Radiation Facility to measure the X-ray power from 50 nW to 1 $$\upmu \hbox {W}$$ . The purpose is to verify the accuracy of the X-ray power measurement and the performance of the cryogenic radiometer. The spectral responsivity of a Si photodiode detector calibrated in the Physikalisch-Technische Bundesanstalt of Germany is calibrated at 750 eV again with the cryogenic radiometer based on synchrotron light source. Some important performance parameters (e.g., time constant, responsivity, and nonequivalence error) of the cryogenic radiometer were measured and were in agreement with the design indexes. Calibration results show that total relative uncertainties of X-ray power measurement were below 1% ( $$k=1)$$ , and that good consistency was received compared with the calibrations done by the PTB. The cryogenic radiometer built at 4B7B is reliable and accurate for soft X-ray power measurement. And the performance of the cryogenic radiometer is also very good.

The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. Specifications for the electromagnetic field pulses require that the modulators generate pulses of up to 900 ns flattop duration, +/−12.5 kV and 305 A, with ripple and droop of not more than 200 ppm (+/−2.5 V) with respect to a reference waveform. Inducti ve adder topology has been chosen for the pulse modulators: the output waveform can be adjusted by applying analogue modulation methods. Two full-scale, 12.5 kV, 20-layer, prototype inductive adder have been designed and built at CERN and testing has commenced. The prototypes are planned to be tested with a prototype stripline kicker, installed in a beamline, at ALBA Synchrotron Light Source in Spain. The results of laboratory tests to generate a 10.3 kV flat-top pulse and a controlled decay waveform are presented.

Photoelectron emission from solid surfaces induced by attosecond pulse trains into the electric field of delayed phase-coherent infrared (IR) pulses allows the surface-specific observation of energy-resolved electronic phase accumulations and photoemission delays. We quantum-mechanically modeled interferometric photoemission spectra from the (111) surfaces of Au and Ag, including background contributions from secondary electrons and direct emission by the IR pulse, and adjusted parameters of our model to energy-resolved photoelectron spectra recently measured at a synchrotron light source by Roth et al. [J. Electron Spectrosc. 224, 84 (2018)]. Our calculated spectra and photoelectron phase shifts are in fair agreement with the experimental data of Locher et al. [Optica 2, 405 (2015)]. Our model's not reproducing the measured energy-dependent oscillations of the Ag(111) photoemission phases may be interpreted as evidence for subtle band-structure effects on the final-state photoelectron-surface interaction not accounted for in our simulation.

We present results from beam commissioning of the MAX IV 3 GeV storage ring as well as a summary of the beam dynamics studies that have so for been carried out. We report on injection and accumulation using a single dipole kicker, top-up injection, slow orbit feedback, restoring the linear optics to design, effects of in-vacuum undulators with closed gaps, and adjusting nonlinear optics to achieve design chromaticity correction as well as dynamic aperture sufficient for high injection efficiency and good Touschek lifetime., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The Photon-Ion Spectrometer at PETRA III - in short, PIPE - is a permanently installed user facility at the "Variable Polarization XUV Beamline" P04 of the synchrotron light source PETRA III operated by DESY in Hamburg, Germany. The careful design of the PIPE ion-optics in combination with the record-high photon flux at P04 has lead to a breakthrough in experimental studies of photon interactions with ionized small quantum systems. This short review provides an overview over the published scientific results from photon-ion merged-beams experiments at PIPE that were obtained since the start of P04 operations in 2013. The topics covered comprise photoionization of ions of astrophysical relevance, quantitative studies of multi-electron processes upon inner-shell photoexcitation and photoionization of negative and positive atomic ions, precision spectroscopy of photoionization resonances, photoionization and photofragmentation of molecular ions and of endohedral fullerene ions., Comment: 10 pages, 9 figures

It is shown that two radio frequency deflecting cavities with slightly different frequencies can be used to produce time-dependent orbit deflection to a few special electron bunches circulating in a synchrotron without affecting the majority of the electron bunches. These special bunches produce an x-ray pulse in which transverse position or angle, or both, are correlated with time. The x-ray pulse is then shortened, either with an asymmetrically cut crystal that acts as a pulse compressor, or with an angular aperture such as a narrow slit positioned downstream. The implementation of this technique creates a highly flexible environment for synchrotrons in which users of most beamlines will be able to easily select between the x-rays originated by the standard electron bunches and the short x-ray pulses originated by the special electron bunches carrying a time-dependent transverse correlation.

OCELOT is a novel multiphysics simulation toolkit, which has been in development at European XFEL in collaboration with NRC Kurchatov Institute and DESY since 2011. In this paper we describe its architecture, implementation, and applications in the area of synchrotron light sources and FELs.

We report on the production of an array of active edge silicon sensors as a prototype of a large array. Four Medipix3RX.1 chips were bump bonded to four single chip sized Advacam active edge n-on-n sensors. These detectors were then mounted into a 2 by 2 array and tested on B16 at Diamond Light Source with an x-ray beam spot of 2um. The results from these tests, compared with optical metrology give confidence that these sensors are sensitive to the physical edge of the sensor, with only a modest loss of efficiency in the final two rows of pixels. We present the efficiency maps recorded with the microfocus beam and a sample powder diffraction measurement. These results give confidence that this sensor technology can be used in much larger arrays of detectors at synchrotron light sources., 11 pages, 12 figures

The Cornell Electron-positron Storage Ring (CESR) has been converted from a High Energy Physics electron-positron collider to operate as a dedicated synchrotron light source for the Cornell High Energy Synchrotron Source (CHESS) and to conduct accelerator physics research as a test accelerator, capable of studying topics relevant to future damping rings, colliders and light sources. Some of the specific topics that were targeted for the initial phase of operation of the storage ring in this mode, labeled CESRTA (CESR as a Test Accelerator), included 1) tuning techniques to produce low emittance beams, 2) the study of electron cloud development in a storage ring and 3) intra-beam scattering effects. The complete conversion of CESR to CESRTA occurred over a several year period and is described elsewhere. As a part of this conversion the CESR beam position monitoring (CBPM) system was completely upgraded to provide the needed instrumental capabilities for these studies. This paper describes the new CBPM system hardware, its function and representative measurements performed by the upgraded system.