Generation Synchrotron Light Source Research Articles

New event based timing system for the Taiwan Light Source

The Taiwan Light Source (TLS) is a third generation synchrotron light source that has been in operation since 1993. However, the legacy timing system is obsolete and needs to be upgraded to an event based timing system. This upgrade is intended to replace obsolete components and improve functionality. The new timing system must coordinate the operation of the linac, the White circuit based booster synchrotron, and the storage ring for beam generation, injection, extraction, and accumulation, while also supporting top up operation of the storage ring. To achieve this, a cPCI (CompactPCI) based EPICS IOC (Input Output Controller) and expandable fanless embedded computers have been adopted for the new TLS timing system, replacing the existing VME-based ILC (Intelligent Local Controller) to provide an easy to maintain control environment. However, the resonant excitation of the booster magnets with the event system requires special attention in the design and implementation phases. This paper summarizes the design ideas and implementation process for addressing this issue.

Obtaining picosecond x-ray pulses from fourth generation synchrotron light sources

Obtaining picosecond x-ray pulses from fourth generation synchrotron light sources

High performance platinum contacts on high-flux CdZnTe detectors

The need for direct X-ray detection under high photon flux with moderate or high energies (30–100 keV range) has strongly increased with the rise of the 4th Generation Synchrotron Light Sources, characterised by extremely brilliant beamlines, and of other applications such as spectral computed tomography in medicine and non-destructive tests for industry. The novel Cadmium Zinc Telluride (CZT) developed by Redlen Technologies can be considered the reference material for high-flux applications (HF-CZT). The enhanced charge transport properties of the holes allow the mitigation of the effects of radiation induced polarization phenomena, typically observed in standard CZT materials (LF-CZT) under high photon flux. However, standard LF-CZT electrical contacts led to inacceptable high dark leakage currents on HF-CZT devices. In this work, a detailed study on the characteristics of new optimized sputtered platinum electrical contacts on HF-CZT detectors is reported. The results from electrical and spectroscopic investigations, showed the best performances on HF-CZT detectors with platinum anode, coupled with both platinum or gold cathode. The morphology, structure, and composition of Pt/CZT contact have been analysed by means of Transmission Electron Microscopy (TEM) on microscopic lamellas obtained by Focused Ion Beam (FIB), highlighting the presence of CdTeO3 oxide at the metal semiconductor interface.

Characterization of Pharmaceutical Tablets by X-ray Tomography.

Solid dosage forms such as tablets are extensively used in drug administration for their simplicity and large-scale manufacturing capabilities. High-resolution X-ray tomography is one of the most valuable non-destructive techniques to investigate the internal structure of the tablets for drug product development as well as for a cost effective production process. In this work, we review the recent developments in high-resolution X-ray microtomography and its application towards different tablet characterizations. The increased availability of powerful laboratory instrumentation, as well as the advent of high brilliance and coherent 3rd generation synchrotron light sources, combined with advanced data processing techniques, are driving the application of X-ray microtomography forward as an indispensable tool in the pharmaceutical industry.

Twin-pulse seeding enables pump-probe capabilities in the EUV to soft X-ray spectrum at synchrotron light sources

Having previously reported that separating the two stages of echo-enabled harmonic generation (EEHG) with one or more bending magnet (BM) sections allows the BMs to serve as the desired source of momentum compaction, here we demonstrate that this arrangement can greatly reduce the total energy modulation required by any 4th generation synchrotron light source, leading to higher repetition rates as well as stronger coherent radiation output power, with significant benefits. Since the EEHG beamline performance is mainly determined by the momentum compaction, beam emittances and beta functions of a storage ring lattice, allowing for different separations between the two stages is a straightforward way to increase the momentum compaction of chicane 1. This also enables pump-probe capabilities in a novel context, where twin-pulse seeding on the same electron bunch would allow two distinct radiation pulses with an adjustable delay in the range of 0.1 to 10 ps. In the twin-pulse seeding scheme, the same electron bunch could undergo modulation from two distinct laser pulses. Later stages would produce independent harmonics in subsequent straight sections. There are two variations of this twin-pulse seeding scheme, supporting different scientific applications. With a common modulation in stage 1, the first option allows simultaneously two independent radiation sources, with a full coverage of the EUV (2.5 to 50 nm) to soft X-ray (1.25 to 2.5 nm) spectrum; for the second option, the same stage 2 undulator could generate two coherent pulses both fitting within the FEL bandwidth, or at distinct harmonics. We present particle tracking simulation studies based on the APS-U lattice, including quantum excitation and radiation damping. These simulations indicate that there is no degradation of the modulated longitudinal phase space even when the two stages are separated by as many as 10 BM sections.

Preface

The 13th International Particle Accelerator Conference, IPAC’22, took place at IMPACT Exhibition and Convention Center, Bangkok, Thailand from Sunday, June 12 to Friday, June 17, 2022. IPAC’22 was organized as the first in-person IPAC since the emergence of COVID-19 as a global pandemic and was attended by 742 delegates from 37 countries on all continents. The total includes 118 industry and exhibitor delegates. Hosted by Synchrotron Light Research Institute (Public Organization) - SLRI. SLRI was established in 1996 (originally as National Synchrotron Research Center - NSRC) and is the national synchrotron research institute which also known as “Thai Synchrotron National Lab”, situated in Nakhon Ratchasima, Thailand. SLRI performs its main duties on development, operation, and management of synchrotron light source “Siam Photon Source (SPS)” in order to achieve one of its main goals in production of synchrotron light and provide it for user application on research. The Local Organizing Committee (LOC) consisted of 66 staff from SLRI.There were 169 young scientists or students from all over the world attending the conference. Student grants were offered to 60 of these students thanks to the sponsorship of societies, institutes and laboratories worldwide. The Americas region grants were sponsored by APS-DB, ODU, CLS, SLAC, FRIB, and Jefferson Lab. The Europe region sponsors are EPS-AG, GSI, CNRS/IN2P3, INFN/LNL, CERN, DESY, PSI, CEA Saclay, ELETTRA, CELLS/ALBA, HZB, ESS, Cockcroft Institute, KIT, SOLEIL, ESRF, STFC/DL/ASTeC, MAX IV, and FZJ. The Asian region was sponsored by IPAC’22, SLRI, IPAC’19, ANSTO, SUT, GIT, LION, NSF, iRCT, Ti, Prime Street Advisory, NXPO, PUDITEC, and SPECS. The organizers of IPAC’22 are grateful to all sponsors for their valued support of students.Welcome remarks were made by Prapong Klysubun (SLRI), Chair of the Organizing Committee (OC). Yoshihiro Funakoshi (KEK), Enrica Chiadroni (INFN/LNF), and David Tarazona (Cornell University) opened the scientific program with presentations, respectively, on “The SuperKEKB Has Broken the World Record of the Luminosity”, “Progress Towards Demonstration of a Plasma Based FEL”, and “The Accelerator and Beam Physics of the g-2 Experiment”. The conference opening ceremony was on Monday afternoon and presided over by H.R.H. Princess Maha Chakri Sirindhorn featuring Special Plenary Talks from Chris Polly (Fermilab) on “Growing Expectations for New Physics” and Prapaiwan Sunwong (SLRI) on “SPS-II: A 4th Generation Synchrotron Light Source in Southeast Asia”.The program was closed with illuminating presentations by Mike Seidel (PSI) on “Towards Efficient Particle Accelerators - a Review”; Manjit Dosanjh (CERN/Oxford University) on “Accelerating the Future: Designing a Robust and Affordable Radiation Therapy Treatment System for Challenging Environments”; and Tomoki Nakamura (Tohoku University) on “Synchrotron Light Illuminates the Origin of the Solar System”.There were 36 invited and 52 contributed oral presentations of very high quality presented during the week. The regional distribution of talks was 16.7 % from Asia, 59.1 % from Europe, and 24.2 % from the Americas. The gender ratio for oral presentations was 71.6 % male and 28.4 % female. The oral presentations were 79.5 % onsite talks and 20.5 % remote talks.

Toward fully coherent soft x-ray free-electron laser via echo-enabled harmonic generation in fourth generation synchrotron light sources.

Having previously reported on bunching via echo-enabled harmonic generation (EEHG) as an effective way to improve the longitudinal coherence in the NSLS-II storage ring [X. Yang et al., Sci. Rep. 12, 9437 (2022)], we demonstrate that this EEHG scheme can be easily adopted to any fourth generation diffraction-limited synchrotron light source with significant benefits. The advantage of the scheme is that it requires no change of the lattice and is fully compatible with other beamlines. Since the EEHG performance is mainly determined by the momentum compaction, beam emittances, and beta functions of a SR lattice, we have identified these crucial parameters and successfully built a generalized model, which can predict the performance of nearly any SLS. Regarding the fourth generation SLSs, momentum compactions are often significantly smaller; thus, to cover the x rays with a photon energy of up to 1keV, we utilize a specific design, including a 250nm seed-laser wavelength. Our model predicts that for most of the current and future fourth generation SLSs, the EEHG scheme can produce significant prebunching up to harmonic 200 and, thus, generate a few MW scale peak power at 1.25nm wavelength.

Status Report of Sirius Delta Undulator

The first Delta undulator for Sirius, a 3 GeV <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$4^\mathrm{th}$</tex-math></inline-formula> generation synchrotron light source located in Brazil, is currently being built. It will be the first undulator of this type to be used in a storage ring based light source. The undulator has a 1.2 m long pure permanent magnet structure with 21 periods of 52.5 mm, a 13.6 mm fixed gap and four magneticarrays that can be moved in the longitudinal direction to provide full polarization control. This paper presents an overview of the Delta undulator project regarding its design, construction, measurements and field correction methods.

Equilibrium of an arbitrary bunch train with cavity resonators and short range wake: Enhanced iterative solution with Anderson acceleration

This paper continues the work of two previous treatments of bunch lengthening by a passive harmonic cavity in an electron storage ring. Such cavities, intended to reduce the effect of Touschek scattering, are a feature of fourth generation synchrotron light sources. The charge densities in the equilibrium state are given by solutions of coupled Ha\"issinski equations, which are nonlinear integral equations. If the only wake fields are from cavity resonators, the unknowns can be the Fourier transforms of bunch densities at the resonator frequencies. The solution scheme based on this choice of unknowns proved to be deficient at the design current when multiple resonators were included. Here we return to the conventional formulation of Ha\"issinski equations in coordinate space, the unknowns being charge densities at mesh points on a fine grid. This system would be awkward to solve by the Newton method used previously, because the Jacobian matrix is very large. Here a new solution is described, which is both Jacobian-free and much simpler. It is based on an elementary fixed point iteration, accelerated by Anderson's method. The scheme is notably fast and robust, accommodating even the case of extreme over-stretching at current far beyond the design value. The Anderson method is promising for many problems in accelerator theory and beyond, since it is quite simple and can be used to attack all kinds of nonlinear and linear integral and differential equations. Results are presented for ALS-U, with updated design parameters. The model includes harmonic and main r.f. cavities, compensation of beam loading of the main cavity by adjustment of the generator voltage, and a realistic short range wake field (rather than the broad-band resonator wake invoked previously).

Studies on Transverse Resonance Island Buckets in third and fourth generation synchrotron light sources

A Transverse Resonance Island Bucket optics has a betatron tune close to a resonance, such that the particle motion is governed by non-linear terms in the equation of motion. This results in additional stable fixed points in transverse phase-space, which can be populated with a single RF-bunch filling pattern. Thus, these optics have the potential of providing pseudo single-bunch operation, i.e. allows some beamlines to receive light pulses at the revolutionary frequency while the remaining beamlines continue to receive pulses with a frequency set by the ring RF. By blocking either the synchrotron radiation from the standard orbit or secondary orbit each beamline can individually choose whether they want multi- or single-bunch synchrotron radiation. Transverse Resonance Island Bucket optics were achieved in both MAX IV storage rings. In particular, the optics of the 1.5 GeV ring has been characterized both theoretically and experimentally, and we show that TRIBs are achieved in a lattice without any octupolar elements. Furthermore, a feasibility study was performed which indicates that the beamlines of the 1.5 GeV ring could make use of the synchrotron radiation from the island orbit while blocking the standard orbit radiation.

The design of HEPS global timing system

The high energy photon source (HEPS) is a 4th generation synchrotron light source under construction by the institute of high energy physics. The accelerator complex consists of a 500-MeV Linac, a full-energy synchrotron booster, a 6-GeV synchrotron storage ring (SR), and three e-beam transport lines for injection and extraction among accelerators. A global timing system (GTS) covers the timing needs for all accelerator, beamline, and experiment systems. The GTS is designed to coordinate the injection processes and various measurements and protections. Most systems require that the RMS jitter of the GTS signal is less than 30 ps, while the trigger jitters for the electron gun and SR injection and extraction kickers are less than 10 ps. The HEPS GTS is an event-based timing system based on MicroTCA.4 hardware architecture. The MicroTCA.4 300 series products from the micro-research Finland Oy are implemented in the HEPS GTS system. The RMS jitter, integrated from 1 Hz to 10 MHz, of the 166.6 MHz event clock is 5.489 ps. The RMS jitter of TTL outputs is less than 30 ps. This paper reports the design of the HEPS GTS, which satisfies all of the HEPS physics requirements for timing with preliminary test results shown.

Equilibrium of an arbitrary bunch train in the presence of multiple resonator wakefields

A higher harmonic cavity (HHC), used to cause bunch lengthening for an increase in the Touschek lifetime, is a feature of several fourth generation synchrotron light sources. The desired bunch lengthening is complicated by the presence of required gaps in the bunch train. In a recent paper the author and Venturini studied the effect of various fill patterns by calculating the charge densities in the equilibrium state, through coupled Ha\"issinski equations. We assumed that the only collective force was from the beam loading (wake field) of the harmonic cavity in its lowest mode. The present paper improves the notation and organization of the equations so as to allow an easy inclusion of multiple resonator wake fields. This allows one to study the effects of beam loading of the main accelerating cavity, higher order modes of the cavities, and short range geometric wakes represented by low-$Q$ resonators. As an example these effects are explored for ALS-U. The compensation of the induced voltage in the main cavity, achieved in practice by a feedback system, is modeled by adjustment of the generator voltage through a new iterative scheme. Except in the case of a complete fill, the compensated main cavity beam loading has a substantial effect on the bunch profiles and the Touschek lifetimes. A $Q=6$ resonator, approximating the effect of a realistic short range wake, is also consequential for the bunch forms.

Development of a stripline kicker for the Hefei Advanced Light Facility

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.

Revealing the Elemental Distribution within Latent Fingermarks Using Synchrotron Sourced X-ray Fluorescence Microscopy.

Fingermarks are an important form of crime-scene trace evidence; however, their usefulness may be hampered by a variation in response or a lack of robustness in detection methods. Understanding the chemical composition and distribution within fingermarks may help explain variation in latent fingermark detection with existing methods and identify new strategies to increase detection capabilities. The majority of research in the literature describes investigation of organic components of fingermark residue, leaving the elemental distribution less well understood. The relative scarcity of information regarding the elemental distribution within fingermarks is in part due to previous unavailability of direct, micron resolution elemental mapping techniques. This capability is now provided at third generation synchrotron light sources, where X-ray fluorescence microscopy (XFM) provides micron or submicron spatial resolution and direct detection with sub-μM detection limits. XFM has been applied in this study to reveal the distribution of inorganic components within fingermark residue, including endogenous trace metals (Fe, Cu, Zn), diffusible ions (Cl-, K+, Ca2+), and exogeneous metals (Ni, Ti, Bi). This study incorporated a multimodal approach using XFM and infrared microspectroscopy analyses to demonstrate colocalization of endogenous metals within the hydrophilic organic components of fingermark residue. Additional experiments were then undertaken to investigate how sources of exogenous metals (e.g., coins and cosmetics) may be transferred to, and distributed within, latent fingermarks. Lastly, this study reports a preliminary assessment of how environmental factors such as exposure to aqueous environments may affect elemental distribution within fingermarks. Taken together, the results of this study advance our current understanding of fingermark composition and its spatial distribution of chemical components and may help explain detection variation observed during detection of fingermarks using standard forensic protocols.

Laser technology in Poland: 2013–2016

This paper presents the state of art of laser technologies in Poland. A list of primary laser technology development centers is included. The involvement of Polish scientists in the development of lasers and fourth generation synchrotron light sources as well as their applications is discussed. The development of laser applications in medical therapy and diagnostics, material micro- and macro-processing as well as environmental monitoring and protection, safety, and security is presented.

Two year operational experience with the TPS vacuum system

The Taiwan Photon Source (TPS), a 3-GeV third generation synchrotron light source, was commissioned in 2014 December and is now currently operated in top-up mode at 300mA for users. During the past two years, the machine was completed to meet design goals with among others the installation of superconducting cavities (SRF), the installation of insertion devices (ID) and the correction of vacuum chamber structure downstream from the IDs. The design goal of 500mA beam current was achieved with a total accumulated beam dose of more than 1000Ah, resulting in three orders of magnitude reduction of out-gassing. As the beam current was increased, a few vacuum problems were encountered, including vacuum leaks, unexpected pressure bursts, etc. Vacuum related issues including high pressure events, lessons learned and operational experience will be presented and discussed in this paper.

MHz frame rate hard X-ray phase-contrast imaging using synchrotron radiation.

Third generation synchrotron light sources offer high photon flux, partial spatial coherence, and ~10-10 s pulse widths. These enable hard X-ray phase-contrast imaging (XPCI) with single-bunch temporal resolutions. In this work, we exploited the MHz repetition rates of synchrotron X-ray pulses combined with indirect X-ray detection to demonstrate the potential of XPCI with millions of frames per second multiple-frame recording. This allows for the visualization of aperiodic or stochastic transient processes which are impossible to be realized using single-shot or stroboscopic XPCI. We present observations of various phenomena, such as crack tip propagation in glass, shock wave propagation in water and explosion during electric arc ignition, which evolve in the order of km/s (µm/ns).

Rigorous mathematical modelling for a Fast Corrector Power Supply in TPS

To enhance the stability of beam orbit, a Fast Orbit Feedback System (FOFB) eliminating undesired disturbances was installed and tested in the 3rd generation synchrotron light source of Taiwan Photon Source (TPS) of National Synchrotron Radiation Research Center (NSRRC). The effectiveness of the FOFB greatly depends on the output performance of Fast Corrector Power Supply (FCPS); therefore, the design and implementation of an accurate FCPS is essential. A rigorous mathematical modelling is very useful to shorten design time and improve design performance of a FCPS. A rigorous mathematical modelling derived by the state-space averaging method for a FCPS in the FOFB of TPS composed of a full-bridge topology is therefore proposed in this paper. The MATLAB/SIMULINK software is used to construct the proposed mathematical modelling and to conduct the simulations of the FCPS. Simulations for the effects of the different resolutions of ADC on the output accuracy of the FCPS are investigated. A FCPS prototype is realized to demonstrate the effectiveness of the proposed rigorous mathematical modelling for the FCPS. Simulation and experimental results show that the proposed mathematical modelling is helpful for selecting the appropriate components to meet the accuracy requirements of a FCPS.

New experimental perspectives for soft x-ray absorption spectroscopies at ultra-low temperatures below 50 mK and in high magnetic fields up to 7 T.

A new ultra-low temperature experiment including a superconducting vector magnet has been developed for soft x-ray absorption spectroscopy experiments at third generation synchrotron light sources. The sample is cooled below 50 mK by a cryogen free (3)He-(4)He dilution refrigerator. At the same time, magnetic fields of up to ±7 T in the horizontal direction and ±0.5 T in the vertical direction can be applied by a superconducting vector magnet. The setup allows to study ex situ and in situ prepared samples, offered by an attached UHV preparation chamber with load lock. The transfer of the prepared samples between the preparation section and the dilution refrigerator is carried out under cryogenic temperatures. First commissioning studies have been carried out at the Variable Polarization XUV Beamline P04 at PETRA III and the influence of the incident photon beam to the sample temperature has been studied.

ASAP3 - New Data Taking and Analysis Infrastructure for PETRA III

Data taking and analysis infrastructures in HEP (High Energy Physics) have evolved during many years to a well known problem domain. In contrast to HEP, third generation synchrotron light sources, existing and upcoming free electron lasers are confronted with an explosion in data rates driven primarily by recent developments in 2D pixel array detectors. The next generation of detectors will produce data in the region upwards of 50 Gbytes per second. At synchrotrons, data was traditionally taken away by users following data taking using portable media. This will clearly not scale at all.We present first experiences of our new architecture and underlying services based on results taken from the resumption of data taking in April 2015. Technology choices were undertaking over a period of twelve month. The work involved a close collaboration between central IT, beamline controls, and beamline support staff. In addition a cooperation was established between DESY IT and IBM to include industrial research and development experience and skills.Our approach integrates HPC technologies for storage systems and protocols. In particular, our solution uses a single file-system instance with a multiple protocol access, while operating within a single namespace.