Performance Of Beamline Research Articles

Redifining RADEN’s high-resolution neutron imaging capabilities

This study presents a significant development in the Energy-Resolved Neutron Imaging System RADEN, in the Japan Proton Accelerator Research Complex, Japan. Through a systematic study, the collimation power of the facility was reevaluated. What was initially considered to be values of 230, 420, and 760 have been proven to be much higher. To perform the calculation of the L/D factor of the beam, a state-of-the-art method has been used, along with a standard reference sample to measure the resolution of neutron images. To add robustness to the results, the study compares five different scintillators of different composition and thickness [6LiF:ZnS(Ag) of 50, 100, 200, and 300 μm and Gd2O2S of 50 μm]. The calculated collimating power of the beam ranges between 470 and 1520. These results place a spotlight on an existing discrepancy between the geometrically calculated L/D and the actual measurable quantity, as well as highlight the superior performance of the RADEN beamline.

Assessment of imaging performance for metal alloys of the first Italian neutron imaging beamline NICHE (Pavia, Italy)

In this paper, the imaging capabilities and performance of the new neutron imaging beamline developed at the LENA facility of Pavia (Italy) in the framework of the NICHE project (Neutron Imaging in Cultural HEritage) are presented. For this purpose, the estimation of bronze and brass alloys attenuation coefficient has been obtained through imaging analysis of a set of Cu-based alloy reference samples produced ad-hoc with chemical composition similar to ancient artefacts. In addition, some samples were realised using a different cooling ramp in order to test the influence of the alloy production procedures in neutron attenuation. Moreover, the tomographic capabilities of the beamline were tested for different metallic and plastic materials.

Ray Tracing of the New Multi-Modal X-ray Imaging Beamline PolyX at SOLARIS National Synchrotron Radiation Centre

The aim of the presented research is to evaluate the potential performance of a new bending magnet X-ray beamline—PolyX, designed for microimaging and microspectroscopy at the National Synchrotron Radiation Centre SOLARIS in Krakow. Due to the short beamline length (<15 m), PolyX uses compact polycapillary and single-bounce monocapillary optics for X-ray focusing in the 4–15 keV energy range. Polycapillary optics require a dedicated approach for an efficient simulation of X-ray propagation in multiple capillary channels. Therefore, the PolyX beamline was ray traced by combining XRT (XRayTracer) and polycap libraries. In addition, to estimate the X-ray fluorescence spectra excited by focused beams, Monte Carlo simulations were conducted using XMI-MSIM. All simulations were aimed to estimate the crucial X-ray beam properties, i.e., the flux, the spot size, and the energy spectrum, for monochromatic and polychromatic X-ray beams.

GIWAXS experimental methods at the NFPS-BL17B beamline at Shanghai Synchrotron Radiation Facility.

The BL17B beamline at the Shanghai Synchrotron Radiation Facility was first designed as a versatile high-throughput protein crystallography beamline and one of five beamlines affiliated to the National Facility for Protein Science in Shanghai. It was officially opened to users in July 2015. As a bending magnet beamline, BL17B has the advantages of high photon flux, brightness, energy resolution and continuous adjustable energy between 5 and 23 keV. The experimental station excels in crystal screening and structure determination, providing cost-effective routine experimental services to numerous users. Given the interdisciplinary and green energy research demands, BL17B beamline has undergone optimization, expanded its range of experimental methods and enhanced sample environments for a more user-friendly testing mode. Thesemethods include single-crystal X-ray diffraction, powder crystal X-ray diffraction, wide-angle X-ray scattering, grazing-incidence wide-angle X-ray scattering (GIWAXS), and fully scattered atom pair distribution function analysis, covering structure detection from crystalline to amorphous states. This paper primarily presents the performance of the BL17B beamline and the application of the GIWAXS methodology at the beamline in the field of perovskite materials.

Incident beamline design for a modern cold triple axis spectrometer at the High Flux Isotope Reactor

A modern cold triple axis spectrometer is being planned for the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. Here, we describe the design of an incident beamline that will put a flux of ∼108ncm2s on a sample with an area of 2 cm × 2 cm. It takes current physical constraints at HFIR into account and it can accommodate both single and multiplexed analyzer-detector secondary spectrometers and large superconducting magnets. The proposed incident beamline includes a multi-channel guide with horizontal focusing, a neutron velocity selector, components to facilitate an incident beam polarization option, and a double-focusing pyrolytic graphite monochromator. This work describes the process of optimizing the guide system and monochromator and summarizes the expected performance of the incident beamline for non-polarized operation.

Infrared spectroscopy across scales in length and time at BESSY II.

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 × 30 nm × 12 nm. Potential steps for further optimization of the beamline performance are discussed.

A hybrid surface shape control method for optimizing thermal deformation of FEL reflection mirror

The surface shape errors induced by thermal deformation of the free electron lasers (FEL) beamline reflection mirror directly affect the quality of FEL beam. In order to reduce the thermal deformation and meet the stringent requirements of surface shape error of the FEL reflection mirror, this paper proposes a surface shape control method that combines mirror bending and active thermal control (ATC) technique, aiming to minimize surface shape errors and enhance the overall performance of the FEL beamline. A bending mechanism has been designed to achieve a bending sensitivity of 60 nrad RMS/N using only one bending actuator. It does not obstruct the FEL beam with extremely small incident angle. This mechanism can compensate for thermal deformation by eliminating the cylindrical surface component of the thermal deformation. Additionally, a novel ATC algorithm is proposed based on the Tikhonov regularization method. When combined with the bending mechanism, it proves effective in controlling the surface shape of the reflection mirror. The simulation results indicate that this surface control method can effectively reduce the surface shape errors of the reflection mirror. Taking the 3 nm wavelength FEL as an example, the RMS value of surface slope error of the reflection mirror is substantially reduced from 17.1974 μrad (with heat load) to 0.0913 μrad after bending. Based on the bending result, the ATC technique further reduces the slope error to 0.0303 μrad RMS. For 1 nm and 2 nm wavelength FELs, the mirror slope errors ultimately reach 0.0147 μrad RMS and 0.0295 μrad RMS respectively. This surface shape control method ensures that the reflection mirror slope errors meet the beamline requirement, which is 0.05 μrad RMS, thereby guaranteeing the beam quality.

Evaluation of a compact electron preinjector using a low beta (β) acceptance X-band accelerating structure

At the University of Melbourne X-LAB we are investigating the use of a low β acceptance X-band accelerating structure as part of the design of an all X-band RF electron preinjector optimised for the production of low emittance electron bunches for medical physics applications and compact light source development.In this work we will elaborate on the estimated performance, design issues, and optimisation methodology of the preinjector beamline.

Research on an active control method of double crystal monochromator with disturbance observer

The double crystal monochromator (DCM) is the core equipment of high flux and high monochromatic light on the synchrotron beamline, which directly affects the performance of the synchrotron hard X-ray beamline in terms of stability. To meet the requirements for the stability of the nano-radian magnitude of the DCM for the 4th-generation synchrotron light source, this paper presents a method to suppress the primary resonance of the system using an integral lead compensation notch filter and eliminate the higher-order positive and negative resonance peaks with a dual second-order notch filter. The bandwidth of the DCM system is enhanced to meet the system speed requirements. Meanwhile, the mechanical coupling is considered equivalent to the system's internal disturbance. The disturbance observer is designed to ensure the stability and dynamic performance of the DCM system. The simulation results show that after correction by the integral lead compensation notch filter and the dual second-order notch filter, the system bandwidth can reach 308Hz while maintaining a phase margin of approximately 25°. Furthermore, the stability of DCM can reach an RMS of 0.139 nrad, 16.610 nrad, and 1.431 nm in the Pitch, Roll, and Gap direction, respectively, with the help of a disturbance observer. The paper proposes a method to develop stable DCMs in 4th-generation synchrotron radiation facilities while improving the X-ray beamline performance.

A high-throughput big-data orchestration and processing system for the High Energy Photon Source.

High-data-throughput and multimodal-acquisition experiments will prevail in next-generation synchrotron beamlines. Orchestrating dataflow pipelines connecting the data acquisition, processing, visualization and storage ends are becoming increasingly complex and essential for enhancing beamline performance. Mamba Data Worker (MDW) has been developed to address the data challenges for the forthcoming High Energy Photon Source (HEPS). It is an important component of the Mamba experimental control and data acquisition software ecosystem, which enables fast data acquisition and transmission, dynamic configuration of data processing pipelines, data multiplex in streaming, and customized data and metadata assembly. This paper presents the architecture and development plan of MDW, outlines the essential technologies involved, and illustrates its current application at the Beijing Synchrotron Radiation Facility (BSRF).

Research on the simulation environment of hard X-ray nanoprobe beamline station

In the hard X-ray nanoprobe beamline station, experiments need to be performed by adjusting the optical equipment in order to obtain good beamline performance. Due to many factors, only through the use of intelligent optimization, the beamline performance can be quickly improved. Therefore, an intelligent optimization method is proposed in this work to improve the performance of the beamline rapidly by using an adaptive algorithm to optimize the motor shaft of each device. Moreover, this paper introduces the simulation environment of the hard X-ray nanoprobe beamline equipment. In this environment, a multi-axis parallel optimization model of several optical devices is designed, and the ionization chamber feedback is replaced by Rastrigin function. Furthermore, the differential evolution algorithm is used to verify the model. The optimization tests of multiple devices in the beamline are carried out, and the automatic optimization of the devices is realized. As for the theoretical result, the designed intelligent beamline optimization program is capable of converging to the optimal value within 3-6 minutes on the simulation platform, this automated process could potentially enhance beamline adjusting efficiency by 10-20 times compared to manual beamline adjusting.

Comparison among possible design solutions for the Stray Field Shielding System of the DTT Neutral Beam Injector

Within the effort on the conceptual design of the Divertor Test Tokamak (DTT) Neutral Beam Injector (NBI), the design of the Stray Field Shielding System (SFSS) for DTT NBI is under development, to suppress the potentially harmful effects of the stray poloidal field from the tokamak on the accelerated charged beam. Various possible design solutions to solve this problem are presented and compared, with a particular focus on the stray field minimization procedure and particle tracing simulations, used during the design validation phase with the objective of maximizing beamline performances.

The Complex, Unique, and Powerful Imaging Instrument for Dynamics (CUPI2D) at the Spallation Neutron Source (invited).

The Oak Ridge National Laboratory is planning to build the Second Target Station (STS) at the Spallation Neutron Source (SNS). STS will host a suite of novel instruments that complement the First Target Station's beamline capabilities by offering an increased flux for cold neutrons and a broader wavelength bandwidth. A novel neutron imaging beamline, named the Complex, Unique, and Powerful Imaging Instrument for Dynamics (CUPI2D), is among the first eight instruments that will be commissioned at STS as part of the construction project. CUPI2D is designed for a broad range of neutron imaging scientific applications, such as energy storage and conversion (batteries and fuel cells), materials science and engineering (additive manufacturing, superalloys, and archaeometry), nuclear materials (novel cladding materials, nuclear fuel, and moderators), cementitious materials, biology/medical/dental applications (regenerative medicine and cancer), and life sciences (plant-soil interactions and nutrient dynamics). The innovation of this instrument lies in the utilization of a high flux of wavelength-separated cold neutrons to perform real time in situ neutron grating interferometry and Bragg edge imaging-with a wavelength resolution of δλ/λ ≈ 0.3%-simultaneously when required, across a broad range of length and time scales. This manuscript briefly describes the science enabled at CUPI2D based on its unique capabilities. The preliminary beamline performance, a design concept, and future development requirements are also presented.

Design and performance of a novel low energy multispecies beamline for an antihydrogen experiment

The ALPHA Collaboration, based at the CERN Antiproton Decelerator, has recently implemented a novel beamline for low energy (≲100 eV) positron and antiproton transport between cylindrical Penning traps that have strong axial magnetic fields. Here, we describe how a combination of semianalytical and numerical calculations was used to optimize the layout and design of this beamline. Using experimental measurements taken during the initial commissioning of the instrument, we evaluate its performance and validate the models used for its development. By combining data from a range of sources, we show that the beamline has a high transfer efficiency and estimate that the percentage of particles captured in the experiments from each bunch is (78±3)% for up to 105 antiprotons and (71±5)% for bunches of up to 107 positrons.8 MoreReceived 21 November 2022Accepted 8 March 2023DOI:https://doi.org/10.1103/PhysRevAccelBeams.26.040101Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBeam opticsPenning trapsPhysical SystemsLow- & intermediate-energy acceleratorsNonneutral plasmasAtomic, Molecular & OpticalAccelerators & BeamsPlasma Physics

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.

Functional optimization for a Beam Driven Plasma Neutralizer in DEMO Neutral Beam Injector

The Beam Driven Plasma Neutralizer (BDPN) has been proposed as a more efficient alternative to the gas neutralizer for negative-ion based Neutral Beam Injection (NNBI). In this paper we model the performance of an entire NNBI beamline with a BDPN. We simultaneously consider all the relevant physics and engineering aspects, the most important being the plasma density and degree of ionization inside the BDPN as a function of its geometry and feed gas flow, the geometrical transmission of the beamline, the dependence of the neutral gas distribution in the beamline on the geometry of the beamline components and gas flows, and the species evolution of the extracted D− beam through this neutral and charged particle distribution. Furthermore, we calculate the heat loads expected on the BDPN parts and on the NBI components located downstream of it and study the effect of the magnetic cusp field across the BDPN entrance on beamline transmission. While our results constitute an optimization only under the applied boundary conditions, we find that the beamline with a BDPN increases the system’s wall plug efficiency by about 13% to 0.34 from the 0.30 estimated for a gas neutralizer.

The beam transport system for the Small Quantum Systems instrument at the European XFEL: optical layout and first commissioning results.

The Small Quantum Systems instrument is one of the six operating instruments of the European XFEL, dedicated to the atomic, molecular and cluster physics communities. The instrument started its user operation at the end of 2018 after a commissioning phase. The design and characterization of the beam transport system are described here. The X-ray optical components of the beamline are detailed, and the beamline performances, transmission and focusing capabilities are reported. It is shown that the X-ray beam can be effectively focused as predicted by ray-tracing simulations. The impact of non-ideal X-ray source conditions on the focusing performances is discussed.

Application of adaptive filtering algorithm to the stability problem for double crystal monochromator. Part I: Typical filtering algorithms

The double crystal monochromator (DCM) is one of the critical beamline devices in synchrotron radiation facilities. With the continuous improvement of the performance of the X-ray beamline of synchrotron radiation sources and the constant application of fourth-generation synchrotron radiation sources, higher requirements for the stability of the DCM have been introduced. Based on previous engineering experience, the LN2 cooling system is the most critical factor affecting DCM’s stability. In this paper, the vibration suppression performance of FxLMS (filter-x Least Mean Square), FxNLMS(filter-x Normalized Least Mean Square), FxSDLMS(filter-x Sign-Data Least Mean Square), FxSELMS(filter-x Sign-Error Least Mean Square) and FxSSLMS(filter-x Sign-Sign Least Mean Square) are verified under Bragg@12.66 KeV and Bragg@9 KeV operating conditions for the measured vibration signals of DCM at SSRF(Shanghai Synchrotron Radiation Facility). The results show that the FxNLMS algorithm has higher convergence accuracy, excellent vibration suppression performance, and the ability to counter unknown disturbances compared with other typical filtering algorithms.

Strategies to minimize beam and sample vibration-induced instabilities at the microfocus MX XAIRA beamline at ALBA

The performance of microfocus beamlines, and ultimately the quality of the diffraction data, is very sensitive to vibrations affecting the optical elements and the sample stages and holder. We report here the strategies applied in the design of the microfocus MX XAIRA beamline at ALBA synchrotron to mitigate the effects of two relevant sources of vibrations: circulation of LN2 flow to evacuate the thermal load on the monochromator and cryocooling gas stream being blown on the sample. The internal shape and size of the two cooling pads that clamp the monochromator optics have been designed to minimize the turbulences in the liquid nitrogen flow while maximizing heat transfer. Computational Fluid Dynamics (CFD) simulations and some preliminary metrology tests are presented. Besides, in the end-station, the cryo-cooler is blowing typically a 5-10 L/min flow of nitrogen or helium gas at 100K on the sample, inducing vibrations in the micron range. The optimal geometrical configuration between the sample holder and the cryocooler has been assessed by means of CDF simulations and metrology tests.

Development of monochromators for HEPS

Monochromator plays a key role in the performance of a synchrotron beamline, it determines a beamline’s energy range, bandwidth, flux, focal sizes, coherence, etc., and it has been the limiting optic in a beamline for a long time. Many efforts have been made in order to improve the performance of the monochromators around the world. The HEPS project will need a batch of monochromators and some of them are built in house, many technical problems needed to be solved. A double crystal monochromator prototype has been developed, tested, then modified by improving the mechanical stability, switching to mechanism based on flexures to drive the second crystal. A quick EXAFS Channel-Cut crystal monochromator was designed for the HEPS XAFS beamline, driven by torque motor and closed loop controller. The design aspects and some test results of both monochromators will be introduced. Results show that the design is feasible and meet the requirements of both beamlines.