bluuebunny/crossref_metadata_2025 huggingface dataset:
Asymmetric tunneling of Bose–Einstein condensates
Authors: Lindberg Dusty R , Gaaloul Naceur , Kaplan Lev , Williams Jason R , Schlippert Dennis , Boegel Patrick , Rasel Ernst-Maria , Bondar Denys I
Published: December 2022

In his celebrated textbook, Quantum Mechanics: Nonrelativistic Theory, Landau argued that, for single particle systems in 1D, tunneling probability remains the same for a particle incident from the left or the right of a barrier. This left–right symmetry of tunneling probability holds regardless of the shape of the potential barrier. However, there are a variety of known cases that break this symmetry, e.g. when observing composite particles. We computationally (and analytically, in the simplest case) show this breaking of the left–right tunneling symmetry for Bose–Einstein condensates (BECs) in 1D, modeled by the Gross–Pitaevskii equation. By varying g, the parameter of inter-particle interaction in the BEC, we demonstrate that the transition from symmetric (g = 0) to asymmetric tunneling is a threshold phenomenon. Our computations employ experimentally feasible parameters such that these results may be experimentally demonstrated in the near future. We conclude by suggesting applications of the phenomena to design atomtronic diodes, synthetic gauge fields, Maxwell’s demons, and black-hole analogues.
Study of a deep learning-based method for improving the spectral resolution of the spectral scanning hyperspectral imaging system via synthetic spectral image data
Authors: Kim Suhyun , Jung Sera , Yoon Jonghee
Published: December 2022

Hyperspectral imaging (HSI) techniques, measuring spatial and spectral information, have shown the ability to identify targets based on their spectral features. Among many HSI methods, a spectral scanning HSI method implemented using a tunable filter has been widely used in various applications due to wide-area HSI capability and cost-effectiveness. However, the limitation of the spectral scanning method is poor spectral resolution compared to other spectral imaging methods using dispersive materials. To overcome this limitation, we exploited a recently developed deep-learning model that retrieves multispectral information from an red, green, and blue image. Moreover, this study proposed that a color chart consisting of 18 colors could be a standard target for training the deep-learning model under various spectral scanning HSI conditions. The simulation work was performed to demonstrate the feasibility of the proposed method using synthetic hyperspectral images. Realistic synthetic data was prepared using spectral data obtained via a spectrometer (ground-truth data) and artificial filters emulating a liquid-crystal tunable filter. We found that the deep-learning model trained via a supervised learning approach using synthetic hyperspectral images successfully retrieved high-resolution spectral data. In addition, the trained deep-learning model retrieved robust spectral profiles of random colors which were not used in the training process. Collectively, the deep learning-based spectral scanning method could improve the spectral resolution of the imaging system, and the color chart would be a good and practical standard training target for the deep learning model.
Mild air oxidation of boron nitride nanotubes. Application as nanofillers for thermally conductive polycarbonate nanocomposites
Authors: Bodin Antoine , Pietri Thomas , Simonato Jean-Pierre
Published: December 2022

Boron nitride nanotubes (BNNTs) have experienced considerable growth in recent years due to their unique intrinsic properties, in particular for the fabrication of polymer nanocomposites. Dispersion of pure BNNTs in nanocomposites is often difficult due to their poor compatibility with most polymer matrices. An approach involving the creation of hydroxyl groups on their surface could improve their dispersion. While some harsh oxidation processes have been reported so far, a mild oxidation of BNNTs using air as the oxidant is reported here. This new catalytic reaction leads to slightly oxidized BNNTs, which were characterized by scanning electron microscope, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. Polycarbonate nanocomposites were then fabricated using pristine and oxidized BNNTs as nanofillers. The measured thermal conductivity increased linearly with the mildly oxidized BNNTs content. It reached a five-fold increase up to 1.19 W m.K−1 at 15% vol. content which is significantly improved over nanocomposites fabricated with severely oxidized BNNTs, while the electrically insulating character remained unchanged.
Embedding thermocouples in SS316 with laser powder bed fusion*
Authors: Hyer Holden C , Carver Keith , List III Fred A , Petrie Christian M
Published: December 2022

Recent advances in manufacturing technologies have enabled the fabrication of complex geometries for a wide range of applications, including the energy, aerospace, and civil sectors. The ability to integrate sensors at critical locations within these complex components during the manufacturing process could benefit process monitoring and control by reducing reliance on models to relate surface measurements to internal phenomena. This study investigated embedding thermocouples in a SS316 matrix using laser powder bed fusion. Under optimal processing conditions, embedded thermocouples were characterized post-building, finding good bonding to the matrix with no melt pool penetration to the sensing elements. Moreover, the embedded thermocouple performed similarly to an identical non-embedded thermocouple during thermal testing to 500 °C with only a slight difference in response time, which was attributed to the differences in mass and the associated thermal time constants.
Computational study on the discharge dynamics of atmospheric pressure He plasma driven by high frequency AC voltage
Authors: Wang Lijun , Liu Jie , Zhao Huan , Lin Xin , Lian Zhuoxi
Published: December 2022

A two dimensional self-consistent fluid model has been established to investigate the discharge dynamics of double-ring electrode He atmospheric pressure plasma jet (APPJ) driven by high frequency AC voltage. The difference of the internal stream and external jet and the influence of the change of applied voltage polarity on plasma discharge characteristics has been discussed. It has been discovered that the capacitive breakdown characteristic of the double ring electrode significantly enhances the intensity of the APPJ. The discharge intensity of the external jet is stronger than that of the internal stream and the propagation speed of the external jet is faster than that of the internal stream due to the ionization and Penning ionization of N2and O2. Therefore, the density of reactive species in the external jet is greater than that in the internal stream. When the negative voltage is applied to the downstream electrode, the propagation direction of the internal stream changes to the downstream electrode. The ionization of the external jet is also concentrated near the downstream electrode and in the streamer head. The radial propagation distance of the external jet on the dielectric surface continues to increase and the peak value of the radial electric field is concentrated at the streamer head. When the applied voltage changes from negative to positive, the propagation direction of the internal stream turns to the upstream electrode and the upstream jet is formed above the electrode. At the beginning of the positive cycle, the radial propagation distance of the external jet is shortened due to the effects of the electron attachment of O2and the radial electric field. With the increase of applied voltage, the ionization in the streamer head gradually increases, which promoted the radial propagation of external jet.
Tunable Bloch surface wave constructed by two-dimensional lithium niobate grating for biosensor
Authors: Ge Daohan , Wang Huashuai , Shi Jiakang , Zhou Yujie , Zhang Liqiang
Published: December 2022

In this study, a Bloch surface wave (BSW) biosensor coupled with a two-dimensional lithium niobate grating was designed. The influence of the nonlinear characteristics of lithium niobate on the BSW sensor was theoretically investigated, and the tunability of the BSW was studied using the excitation schemes of n
e and n
o. To confine the energy on the surface of the solution in contact with the sensor, we introduce a distributed Bragg reflector mirror (DBR) consisting of four pairs of 76% and 42% porosity porous silicon films. A layer of lithium niobate grating is deposited on top of DBR to excite Bloch surface waves(BSW) and introduce the concept of azimuth detection in the study of the tunable properties of lithium niobate. Then, the azimuth angle of the resonance peaks excited along the n
e and n
o directions of lithium niobate varied by approximately 5°.
First-principles prediction of 1H-Na2Se monolayer: effects of external strain and point defects associated with constituent atoms
Authors: Vu Tuan V , Nguyen Duy Khanh , Guerrero-Sanchez J , Hoat D M
Published: December 2022

In this work, a new Na2Se monolayer in 1H-phase, with interesting properties similar to transition metal dichalcogenides (TMDs), has been predicted using first-principles calculations. Results reveal good stability and wide direct gap semiconductor nature, with an energy gap of 0.82(1.45) eV as determined by standard PBE(hybrid HSE06) functional. This two-dimensional (2D) material exhibits poor stability under compressive strain due to the sensitive ZA acoustic phonon mode. In contrast, it only becomes unstable with tensile strain from 9% due to the elongation of chemical bonds reflected in the optical E” phonon mode. Under effects of lattice tension, the direct gap character is preserved and the band gap increases nearly linearly according to increase the strain strength. In addition, the effects of point defects associated with Na and Se atoms, including vacancies, antisites, and atom adsorption are also examined. Results indicate significant magnetization induced by Na single vacancy, Se
Na
antisite (one Na atom substituted by one Se atom), and Na adsorption on-top of hollow (T
H
) site. In these cases, feature-rich magneto-electronic properties as half-metallic and magnetic semiconductor natures are obtained. In contrast, the formation of 2Na+1Se combined vacancies as well as other defects related to Se atoms leads to an effective band gap modification, even metallization in some cases. Results introduces new promising 2D material for optoelectronic applications and proposes point defect engineering to create artificially novel features for spintronic applications.
Large magnetocaloric effect near room-temperature by tuning the magneto-structural transition in (Mn, Fe)(Ni, Fe)Si alloy
Authors: Panda Shantanu Kumar , Mallick Jyotirekha , Datta Subhadeep , Biswal Sambit Kumar , Guha Shampa , Kar Manoranjan
Published: December 2022

The observation of near room-temperature coupling of both magnetic and structural transitions in Fe substituted Mn-Ni-Si alloy leads to an interesting magneto-structural transition (MST) phenomenon which intensifies the required magnetocaloric parameters for magnetic cooling applications. The crystal structure analysis reveals that temperature as well as Fe substitution work as the driving forces for deforming the orthorhombic unit cell and to stabilize the hexagonal phase. The correlation between the unit cell parameters of both phases confirms that a large change in unit cell volume (∼2.9%) is mainly responsible for the structural transition. The simultaneous substitution of Fe across Ni and Mn sites helps to tune the MST temperature. Both magnetization and calorimetric studies confirm the existence of first-order type structural transition across MST. The [Mn0.64 Ni0.64 Fe0.72 Si] alloy exhibits a large isothermal magnetic entropy change (ΔS

M
) of −19.2

±

0.4 J kg−1 K−1 accompanied by a large value of effective refrigerant capacity (RC

effe
) of 181.8

±

3.7 J kg−1 due to a magnetic field change of 0–30 kOe. The estimated total entropy change associated with the complete structural transition from the calorimetric studies sets an upper limit for the entropy change of the system. The low cost and non-toxic nature of constituent elements, composition-dependent tunability of the transition temperature, and near room-temperature large magnetocaloric parameters make this alloy potentially suitable to be used as a refrigerant in solid-state magnetic cooling technology.
Electron drift velocity in acetylene and carbon dioxide determined from rf breakdown curves
Authors: Lisovskiy V A , Dudin S V , Platonov P P , Yegorenkov V D
Published: December 2022

In this work, we measured the breakdown curves of radio-frequency (13.56 MHz) capacitive discharge in acetylene and in carbon dioxide. The electron drift velocity values were determined in the reduced electric field range 319 Td ≤ E/N ≤ 3409 Td (1 Townsend = 10−17 Vcm2) in acetylene and 272 Td ≤ E/N ≤ 6240 Td in carbon dioxide from turning points on the measured breakdown curves. Treating the electron motion equations and the gas breakdown criterion in the rf electric field we have demonstrated that the method of electron drift velocity determination we employed is universal for arbitrary gasses, and a possible dependence of the electron mobility and diffusion on the reduced electric field strength E/N does not affect the drift velocity values obtained with it. We have demonstrated that in the range of E/N values we have studied the ionization rate exceeds the attachment rate considerably therefore one may neglect the effect the attachment of free electrons to gas molecules plays on electron drift velocity. We have explained the reason why the values of the electron drift velocity we have obtained differ from those obtained by other authors.
Hybrid perovskites thin films morphology identification by adapting multiscale-SinGAN architecture, heat transfer search optimized feature selection and machine learning algorithms
Authors: Vakharia Vinay , Shah Milind , Suthar Venish , Patel Vivek K. , Solanki Ankur
Published: December 2022

The automation in image analysis while dealing with enormous images generated is imperative to deliver defect-free surfaces in the optoelectronic area. Five distinct morphological images of hybrid perovskites are investigated in this study to analyse and predict the surface properties using machine learning algorithms. Here, we propose a new framework called Multi-Scale-SinGAN to generate multiple morphological images from a single-image. Ten different quality parameters are identified and extracted from each image to select the best features. The heat transfer search is adopted to select the optimized features and compare them with the results obtained using the cuckoo search algorithm. A comparison study with four machine learning algorithms has been evaluated and the results confirms that the features selected through heat transfer search algorithm are effective in identifying thin film morphological images with machine learning models. In particular, ANN-HTS outperforms other combinations : Tree-HTS, KNN-HTS and SVM-HTS, in terms of accuracy,precision, recall and F1-score.
Combined electromagnetohydrodynamic flow in microchannels with consideration of the surface charge-dependent slip
Authors: Xing Jingnan , Liu Yongbo
Published: December 2022

In microscale systems, hydrodynamic slip is considered to significantly influence the fluid flow field. Existing theories of electromagnetohydrodynamic flow in hydrophobic microchannels have postulated a constant slip length and ignored the effect of the surface charge on slip. In this study, we extended prior models by considering a combined pressure-driven and electromagnetohydrodynamic flow in microchannels with consideration of surface charge-dependent slip. An analytical solution for this simple model was derived. After a detailed discussion of the obtained results, we demonstrate that the more realistic surface-charge-dependent case has smaller velocities and flow rates than the surface-charge-independent slip case. Considering the effect of the surface charge on slip, the flow rate can be reduced by up to 7% in the currently selected parameter range. Our results are useful for optimizing electromagnetohydrodynamic flow models in microchannels.
On the role of mode resonances in regulating zonal-flow-moderated plasma microturbulence
Authors: Li P.-Y. , Pueschel M.J. , Terry P.W. , Whelan G.G.
Published: December 2022

The onset of turbulent heat transport at a higher temperature gradient than the critical gradient of linear instability, known as the Dimits shift, is a recurring feature of nonlinear simulations for magnetically confined fusion plasmas. Resonance in the nonlinear coupling between the modes that dominate energy transfer can lead to suppression of turbulence and transport above the linear critical gradient. As an expression of this resonance, gyrokinetic simulations show a quasi-coherent interaction between streamers and sidebands coupled through the zonal flow within the Dimits regime. This mechanism is further confirmed by use of artificial complex frequencies which break the resonance. By incorporating corresponding saturation physics, the standard quasilinear model for rapid head flux prediction is improved, which can now predict reduced heat flux in the Dimits regime. In particular, the triplet correlation time, the lifetime of the nonlinear interaction, is shown to be well-approximated by combinations of linear eigenvalues, and yields good representations of the heat flux variation both in and above the Dimits regime. Thus, a reduced but predictive model for transport near the critical gradient of zonal-flow saturated turbulence now exists.
PETRA III Operation with High Availability
Authors: Bieler M. , Keil J. , Kumar Sahoo G. , Schaumann M. , Wanzenberg R.
Published: December 2022

The Synchrotron Light Source PETRA III at DESY is one of the most brilliant storage-ring based X-ray sources for high-energy photons worldwide, which offers scientists unique X-ray experiments in a wide range of fields since 2009. The light source is operated mainly in two operation modes with 480 and 40 bunches at a beam energy of 6 GeV with a maximum beam current of up to 120 mA. High reliability is one of the key requirements for a synchrotron radiation facility. The key performance indicators, availability and mean time between failures (MTBF), could be significantly improved during the operation periods of the last years. As the final milestones of the extension project that started in 2014, a new undulator was installed for the beamline P62 in the Paul P. Ewald hall in 2020, and a new dipole beamline (P66) have been installed in the North East section of PETRA III in 2021.
Commissioning and First Results of the SSRF Phase-II Beamline Project
Authors: Tai Renzhong , Zhao Zhentang
Published: December 2022

The SSRF Phase-II Beamline Project started November 20, 2016 with a 6-year construction period. This project is mainly to construct 18 new beamlines and more than 30 end-stations, as well as the corresponding storage ring upgrades, the user auxiliary laboratories, the beamline technology support laboratories, and the infrastructures. Till now, 11 beamlines have passed the technical acceptance test and been in running. The remaining seven beamlines will be finishing their technical acceptance test soon. The commissioning of the upgraded accelerator is successful including the lattice modification, the new 3rd harmonic superconducting cavity installation and the 650 W helium cryogenic system construction.
Analysis of the error budget for a superconducting undulator SASE line at European XFEL
Authors: Marchetti B. , Casalbuoni S. , Grattoni V. , Serkez S.
Published: December 2022

European XFEL is investing in the development of superconducting undulators (SCUs) for future upgrade of its beamlines. SCUs made of NbTi, working at 2 K, with a period length of 15 mm and a vacuum gap of 5 mm allow covering a range between 54 keV and 100 keV. The effect of mechanical errors in the distribution of the undulator parameter K along the undulators is more relevant for working points at lower photon energy, which are obtained using a higher magnetic field in the undulator. In this article we investigate the effect of error distribution in the K-parameter for a working point at 50 keV photon energy obtained injecting an electron beam with 16.5 GeV energy from the XFEL linear accelerator in a undulator line composed by SCUs with 1.6 T peak magnetic field.
Design, construction, and magnetic field characterization of a Segmented Adaptive-Gap In-Vacuum Undulator prototype for NSLS-II
Authors: Musardo M. , Chubar O. , Tanabe T. , Rank J. , Banerjee A. , Corwin T. , Harder D. , Eng C. , Kitegi C.
Published: December 2022

Segmented Adaptive-Gap in-Vacuum Undulator (SAGU) prototype with different period lengths and gaps in segments for production of high flux and brightness hard X-rays is under development at NSLS-II. According to radiation flux and brightness calculation results, SAGU promises a significant spectral performance gain compared to a conventional in-vacuum undulator, especially in hard X-ray range. In order to reduce the cost of the project, three existing mechanical carriages of Mini-Gap Undulators from the former NSLS X-ray ring were partially de-assembled, redesigned and optimized in order to meet the required mechanical performance of the device. The magnetic module assembly of the first segment has been carried out using a sorting technique which progressively optimizes the magnetic field quality of the device. Additional magnetic tuning, using small dipole kick magnets and virtual shimming, is planned to further improve the electron trajectory straightness, in particular to compensate the angular kicks experienced by the electron beam at segment junctions as it travels through the device. This paper will describe the magnetic and mechanical design as well as the field measurement results, and the magnetic adjustment implemented to properly tune the field strength and minimize the total field integral produced by the segments.
Goubau-Line Set Up for Bench Testing Impedance of IVU32 Components
Authors: Volz Paul , Meseck Atoosa
Published: December 2022

The worldwide first in-vacuum elliptical undulator, IVUE32, is being developed at Helmholtz-Zentrum Berlin. The 2.5 m long device with a period length of 3.2 cm and a minimum gap of about 7 mm is to be installed in the BESSY II storage ring. It will deliver radiation in the soft X-ray range to several beamlines. The proximity of the undulator structure to the electron beam makes the device susceptible to wakefield effects which can influence beam stability. A complete understanding of its impedance characteristics is required prior to installation and operation, as unforeseen heating of components could have catastrophic consequences. To understand and measure the IVU’s impedance characteristics a Goubau-line test stand is being designed. A Goubau-line is a single wire transmission line for high frequency surface waves with a transverse electric field resembling that of a charged particle beam out to a certain radial distance. A concept optimized for bench testing IVUE32-components will be discussed, microwave simulations will be presented, and progress towards a test bench prototype will be shown.
Possibilities at the Polar beamline with APS-U
Authors: Strempfer J , Kearney S , Khan A , Capatina D , Reininger R , Shu D , Wolford C , Golebiowski M , Rebuffi L , Shi X , Kołodziej T , Huang X , Shvyd’ko Y , Choi Y , Fabbris G , Kesgin I , Ivanyushenkov Y , Gluskin E , Haskel D
Published: December 2022

The Polar beamline will make use of the small emittance of the new APS-U storage ring and will offer extremely brilliant and coherent beam of variable polarization in the hard x-ray range. Tailored optics and experimental equipment will enable high spatial resolution dichroic spectroscopy, reflectivity and diffraction in combination with extreme pressures, low temperatures and high magnetic fields. Dichroic direct and ptychographic imaging of magnetic structures is being developed and will make use of the largely enhanced coherence of the low emittance source. We present an overview of the planned instrumentation and the upcoming new exciting possibilities.
Tools for rapid and reliable change of optical configuration at LIX
Authors: Chodankar S. , Yang Lin
Published: December 2022

The LIX beamline (16-ID) at NSLS-II is a scattering beamline dedicated to probing structures in biological samples. The beamline supports both solution scattering and microbeam scanning structural mapping experiments. In addition to providing a stable and reliable beam, the beamline optical system must be able to quickly change configuration to support multiple modes of operation that require different beam properties such as photon energy and spot size, and with minimal effort from the experimenter. In order to do so, we have fine-tuned optical components and implemented automation. The beam stability is maintained using multiple beam position monitors and corresponding feedback on optical components. Vibrational stability of instruments is monitored and correspondingly mitigated. We describe the software and devices developed to automate configuration changes and outline the process of using these tools during operations.
Design of Tender X-ray Absorption Spectroscopy Beamline in Taiwan Photon Source
Authors: Liu D G , Lee M H , Lu Y J , Liang C C , Chang C F , Tu J L , Lee J F , Chen C L
Published: December 2022

A new tender X-ray absorption spectroscopy beamline for operating over the photon energy range from 1.7 keV to 11 keV is under construction at port 32 of the Taiwan Photon Source (TPS). The TPS 32A beamline uses two back-to-back water-cooled double crystal monochromators (DCMs), InSb(111) and Si(111), for achieving the wide energy tunability. The beamline design takes advantage of the low emittance of the TPS accelerator and a bending magnet (BM) to obtain a high-brightness focussed beam. In order to overcome the issue of poor thermal conductivity of InSb(111) crystals while facing high thermal load, we have implemented the following features : (i) we have controlled the flux and heat load by optimizing the source collection angle of 2 × 0.15 mrad2 (h × v), and (ii) we have installed water cooled double-bounce high harmonic rejection mirrors (HHRMs) with a variable incidence angle upstream of the DCM to reduce the heat load on the first InSb crystal. The DCM is followed by a 2:1 toroidal focusing mirror (TFM) which focuses the beam parallel to the floor of the experimental endstation. The simulated focus beam size is 0.9 × 0.9 mm2 (h × v, FWHM) using the InSb(111) DCM at 1.7 keV, and 0.2 × 0.45 mm2 (h × v, FWHM) using the Si(111) DCM at 4 keV, respectively. The photon flux is 1010 -1012 photons s−1 in the energy range of 1.7 to 11 keV at the sample stage after passing through the Be windows. The design parameters of photon flux and beam spot size will facilitate a tender X-ray source for carrying out high-quality X-ray absorption spectroscopy experiments.
The SXP instrument at the European XFEL
Authors: Grychtol P. , Kohlstrunk N. , Buck J. , Thiess S. , Vardanyan V. , Doblas-Jimenez D. , Ohnesorge J. , Babenkov S. , Dommach M. , La Civita D. , Vannoni M. , Rossnagel K. , Schönhense G. , Molodtsov S. , Izquierdo M.
Published: December 2022

The successful implementation of the baseline instruments at the European XFEL has triggered a second phase of instrument developments aiming to extend the portfolio of available techniques. At the soft X-ray undulator (SASE 3), the Soft X-ray Port (SXP) instrument is currently under construction. Conceived as an open port, it focuses primarily on femtosecond time-resolved X-ray photoelectron spectroscopy (TR-XPES), which has proven to be a powerful tool to understand the properties of materials and the interaction between their internal degrees of freedom. The extension of this technique to the soft X-ray energy range is only possible at MHz free electron lasers (FELs) due to space-charge effects which limit the maximum photon flux per pulse on the sample. In this contribution, the SXP instrument at the European XFEL and the implementation of TR-XPES using a momentum microscope are presented. The photon energy range available at SASE 3, 0.25 keV to 3.5 keV, and the variable polarization will allow for the simultaneous characterization of the electronic, magnetic, chemical and structural properties of materials with femtosecond time resolution. To this end, a wide range of laser excitation wavelengths, ranging from the XUV to the THz region, will be available.
Bimorph mirrors at synchrotron beamlines: from walking to flying
Authors: Sutter John P. , Alcock Simon G. , Nistea Ioana-Theodora , Signorato Riccardo , Foster Andrew , Sawhney Kawal
Published: December 2022

With brighter synchrotron sources, automated sample changers, and faster detectors, there is a strong scientific need for rapid and precise variation of the X-ray beam profile, rather than the “set and forget” operation of years past. Piezoelectric bimorph deformable mirrors already allow quick beam profile changes without the heat generation and wear of mechanical devices. Now, their early technological limitations – excessively constraining holders, progressive “junction effect” distortion, and communication bottlenecks with power supplies – are being overcome by a collaboration of scientists and engineers both in industry and at Diamond Light Source. A new generation of bimorph mirrors maintains a stable figure over extended periods of operation. Improved holders and flexible electrical connectors are greatly reducing the mechanical strain imparted to bimorphs, thereby improving their speed, accuracy, and stability. A more sophisticated high voltage power supply has on-board signal processing capacity, allowing large focusing changes within seconds and providing programmable time-varying voltage profiles to counteract piezoelectric creep. The communication between beamline systems and power supplies is being freed of bottlenecks and now runs stably up to 1 Hz. Early tests have already shown that bimorph mirrors can repeatedly switch the size of an X-ray beam in well under 10 seconds. Bimorph mirrors at synchrotron beamlines are now growing beyond the largely static operation of the past and gaining a new dynamism through development projects that are now well advanced. We report on how these endeavours will make it easier for beamlines to utilise the full potential of bimorph mirrors.
Study of Ni/AlN/Ni waveguide system for 8.05 keV incident energy
Authors: Kiranjot  , Modi M H
Published: December 2022

Ni/AlN/Ni waveguide system provides intensity enhancement by a factor of ~30 at 8.05 keV photon energy. In the present study, the effect of deviation of structural parameters (thickness of each layer) along with the surface-interface properties on electric field intensity (EFI) inside an ion beam sputter deposited Ni/AlN/Ni waveguide is investigated. EFI calculations are performed using structural parameters obtained from X-ray reflectivity (XRR) measurements performed using Cu-Kα source. Deposited waveguide structure provides intensity enhancement (~26) slightly lower than optimized value (~30). Furthermore, temporal stability of the structure is investigated using combined XRR and grazing incidence X-ray fluorescence (GIXRF) techniques (at 15 keV photon energy) after about 15 months. Some structural changes are observed which, however, do not lead to further decrease in intensity enhancement inside the waveguide, making it suitable for applications at 8.05 keV photon energy.
Simulations about Stability, Damage, and Heating Impacts for an X-ray Optical Delay Line at SASE3
Authors: Tavakkoly Marziyeh , Grünert Jan , Koch Andreas , La Civita Daniele , Makita Mikako , Meyer Michael , Planas Marc , Serkez Svitozar , Sinn Harald , Wohlenberg Torsten , Vannoni Maurizio
Published: December 2022

European XFEL has initiated a project to facilitate two-color pump-probe spectroscopy with X-rays at the SASE3 soft X-ray undulator. To this end, the controllable temporal delay between the two X-ray pulses is obtained by a magnetic chicane and an optical delay line (ODL) that delay the electron and X-ray beams, respectively. This article focuses on describing the alignment process of the ODL and its related specification. The distance between the experimental station and the ODL is nearly 500 m, thus if one of the mirrors in the ODL is misaligned, the focus spot experiences a noticeable shift. Moreover, a pulse train can include up to 2700 X-ray pulses with a minimum spacing of 222 ns. An increase in temperature per pulse would just add up if there was no heat removal during that time and the material could be damaged during a pulse train. The question arises whether the X-ray optics can survive the high X-ray peak power during a single pulse. Finally, the present study also investigates the damage issue.
An approach for the optical and mechanical design of an X-ray beamline: application to the plane-wave CDI station CATERETÊ/SIRIUS
Authors: Meyer B C , Luiz S A L , Geraldes R R , Volpe L M , Pinto A C , Rodrigues G L M P , Saveri Silva M , Sanfelici L , Meneau F , Polo C C , Kalile T A , Tolentino H C N , Westfahl Junior H
Published: December 2022

Experiments involving nano-focusing or coherence applications require positional stability of a few nanometers and angular stability of tens of nanoradians for all critical optical components along the beamline (in the range of 1 Hz up to 2.5 kHz). Several optical components based on high-precision mechatronics principles with optimized dynamics to cope with those stability requirements have been recently designed and developed at LNLS. An approach combining optical and mechanical design methodologies and processes was applied to new beamline projects. The process starts with optical design using ray-tracing and wave propagation simulations aiming for the specified beam parameters. In a second step, alignment tolerances and stability issues are addressed in the mechanical design of each component. If those requirements cannot be reached in the predictive models based on the available technologies, size and shape of the optics itself or the optical scheme may be redefined restarting the optical simulation. This work applies this beamline design process to the CATERETÊ beamline, which allows for plane-wave CDI experiments. Using side-bounce deflecting cylindrical mirrors and a four-crystal monochromator, a focused beam size of ~ 40 x 30 μm2 (at 9 keV) with a depth-of-focus of 12 m (plane-wave) and high degree of coherence is obtained. We review key aspects of the optical and mechanical designs. In addition, we further extend the modelling process to enable systematic commissioning support by simulating beam parameters on diagnostic elements located downstream each optical element.
Ultra high precision in-vacuum long trace profiler for real time slope determination of optical surface
Authors: Kao Kai-Yang , Fung Hok-Sum , Chao Hsuan-Yao , Yeh Shang-Ching , Chen Jih-Huang , Hua Chih-Yu , Huang Di-Jing , Chen Chien-Te
Published: December 2022

The development of an in-vacuum long trace profiler (IVLTP) which can provide ultra high precision real time measurements on the surface slope of optical elements is reported. The unique features of this instrument include a specifically designed ultra high repeatability linear slide, a pentamirror composed of two plane mirrors of ultra low slope error, and an ultra high vacuum (UHV) compatible complementary metal oxide semiconductor (CMOS) image sensor. The mechanical system is made of Invar 36 alloy to reduce the room temperature drift effect during data acquisitions. Each IVLTP scan completes in 120 seconds, covering a 168 mm of surface length and generating more than 5000 slope data points. The root mean square (RMS) of the difference between two consecutive scans was found to be 0.0081 μrad on average and 0.0045 μrad RMS at its best. The main application of this IVLTP is to provide the real time feedback signals needed for controlling the 25-actuator surface benders of the active mirrors and active gratings installed in the ultra high resolution soft X-ray beamlines at the Taiwan Photon Source (TPS).
Commissioning of a gas monitor detector for an undulator beamline in the VUV and EUV wavelength range
Authors: Kirschner Hans , Kaser Hendrik , Gottwald Alexander
Published: December 2022

A gas detector system was implemented to monitor the absolute photon flux at the insertion device beamline of the Metrology Light Source. This system should overcome the drawbacks in the use of traceably calibrated semiconductor photodiodes, which are prone to radiation-induced degradation and not qualified for permanent real-time monitoring during the measurements at the beamline endstation. Gas monitor detectors are based on atomic photoionization. They do not suffer from radiation-induced degradation, and their transparency makes them suitable for real-time monitoring of the photon flux. We calibrated and commissioned such a monitor at the insertion device beamline in the vacuum- and extreme ultraviolet spectral range from 14 eV to 111 eV photon energy. The resulting photon flux measurement was compared to measurements made with a photodiode and shows deviations below 5 %, which agrees well with the calculated relative uncertainty of 4.7 %.
Coherence properties from speckle contrast analysis at the European XFEL
Authors: Dallari F , Lokteva I , Möller J , Jain A , Roseker W , Westermeier F , Goy C , Boesenberg U , Hallmann J , Rodriguez-Fernandez A , Scholz M , Shayduk R , Madsen A , Grübel G , Lehmkühler F
Published: December 2022

We show the results of speckle contrast analysis at the MID instrument of European XFEL in the hard X-ray regime. Speckle patterns measured from static colloidal samples are compared to results previously obtained at the SPB/SFX instrument. A high degree of coherence of 0.79 is obtained by modelling the q-dependence of the speckle contrast, that corresponds to a number of coherent modes of M = 1.7. Furthermore, the variation of contrast over many pulse trains is exceptional low, resulting in a degree of coherence with a relative standard deviation below 0.1. Our results demonstrate the high stability of coherence properties at European XFEL over many X-ray pulses and pulse trains which is a prerequisite for coherence-based techniques such as MHz X-ray photon correlation spectroscopy.
Simultaneous in-situ x-ray beam profile and intensity measurements with a minimally invasive pixelated diamond monitor
Authors: Martin BW , Fleischauer VE , Muller E
Published: December 2022

Measuring x-ray beam position, profile, and intensity at synchrotron beamlines provides valuable information for all experiments. Sydor’s transparent x-ray camera (TXC), based on technology originally developed at Brookhaven National Laboratory[1], enables these measurements in-line with experiments for live feedback. The TXC has a low beam profile that fits within a standard vacuum flange width and is composed of diamond material for > 90% transmission of > 5 keV x-rays, minimizing disruption of beamline space and the x-ray beam itself. Standard device parameters include 32 x 32, 60 µm pitch pixels, linearity over a 107 – 1016 photons/s dynamic imaging range, < 40 pA noise floor, and total flux measurement mode. Device performance has been evaluated using a pinhole mask with a benchtop silver x-ray tube and during beam focusing tests at the XFP beamline at NSLS-II and flux characterization at the FAST beamline at CHESS. This work will highlight the features of this commercial beam diagnostic, test results, and future directions and applications of the technology.
Energy-Resolving X-ray Imaging at 1 MHz Frame Rate – The HEXITECMHZ ASIC
Authors: Jones L. L. , Bell S. , Church I. , Cline B. , Gardiner T. , Hart M. , Holden J. , Nicholls T. , Nobes J. , Prydderch M. , Roberts M. , Seller P. , Veale M. , Wilson M. D.
Published: December 2022

HEXITECMHZ is an ASIC developed to deliver spectroscopic x-ray imaging at frame rates up to 1MHz for future high-flux-rate applications. Optimised for sensing electron signals from detector materials such as CdTe, CZT, GaAs, and p-type silicon detectors, the design has an array of 80×80 pixels on a pitch of 250 μm, with each pixel capable of measuring single x-ray photons up to energies of 200 keV, with a resolution of 1 keV FWHM. Further improvements in the spatial and spectroscopic resolution are possible due to the pixel’s ability to simultaneously sense positive signals up to 20 keV induced by internal weighting-potential effects from electron signals on neighbouring pixels. A count rate limit of around 106 photons s-1 mm-2 is achieved by converting the signals from all pixels every 1 μs using 12-bit time-to-digital converters – an improvement of two orders of magnitude over previous HEXITEC ASICs. To save power, each converter is shared between groups of eight pixels. Each 76.8kbit data frame is Aurora 64b/66b encoded and serialised over twenty lanes of differential CML, all operating in parallel at 4.1 Gbit/s. In this paper, we present details of the design, including preliminary test results from the ASIC.
Optimization of Solid Angle and Count Rate Capability of an X-ray Detector with Backscattering Geometry
Authors: Ticchi G. , Venturelli M. , Utica G. , Carminati M. , Borghi G. , Zorzi N. , Falkenberg G. , Fiorini C.
Published: December 2022

We study here an optimized geometry for an X-ray detector with hole in the center, as key component for ASCANIO: an innovative 16-channels SDD based spectrometer specifically designed for X-ray fluorescence microscopy (XFM) imaging in synchrotron beamlines. The detector will feature a backscattering geometry with a tilted SDD layout achieving 1 sr solid angle at 8 mm sample distance and a potential Output Count Rate higher than 20 Mcps. The 1 mm thick SDD provides 65 % absorption efficiency at 20 keV while preserving a good energy resolution better than 150 eV thanks to a dedicated cooling system and a low noise front-end electronics. In this paper, the optimization of the detector geometry, in terms of solid angle vs sample distance and maximization of the Output Count Rate introducing a tilting of the SDD units, is discussed.
Development of a direct reading system for an RFID-tagged Uni-puck in liquid nitrogen
Authors: Hiraki M , Matsugaki N , Yamada Y , Hikita M , Senda T
Published: December 2022

The Structural Biology Research Centre in KEK has operated macromolecular crystallography beamlines at the Photon Factory. We have developed the sample exchange system PAM and implemented it on the beamlines for high-throughput, remote, and automated experiments. To prevent sample mix-ups by human error, we identify the Uni-pucks using a commercially available cryo-pin with a two-dimensional (2D) code. However, reading the 2D code sometimes fails because of frost growth when the cold cryo-pin is transferred from liquid nitrogen into the air. To achieve reliable identification, we are developing a sample identification system that uses radio-frequency identification (RFID) tags. We successfully read an RFID tag on a Uni-puck placed in a puck-adapter directly immersed in liquid nitrogen.
Overcoming the data processing challenges of unifying tomography techniques at ESRF
Authors: Payno H , Paleo P , Nemoz C , Cloetens P , di Michiel M , Rack A , Tafforeau P , Solé V A , Viganò N R
Published: December 2022

The ESRF tomography software is undergoing a major re-write, targeted at unifying the tomography user experience, data acquisition, data format, and processing tools. To cope with the inherent large complexity of handling data coming from multiple beamlines, techniques and facilities, we are developing an open source software called NXtomomill. It is named after the NXtomo application class of the NeXus data format, and it will offer advanced data conversion, manipulation and reduction functions. This includes azimuthal integration for X-ray Diffraction CT, and elemental fitting for X-ray Fluorescence CT.

This work will have a remarkable impact on resource management, software robustness, and data storage. With the addition of the new functionality of the ESRF data portal, it will also unlock unimagined opportunities with respect to the automation of artificial intelligence techniques on large and heterogeneous collections of datasets.
Beamline-implemented stretching devices for in situ X-ray scattering experiments
Authors: Euchler E , Sambale A K , Schneider K , Uhlig K , Boldt R , Stommel M , Stribeck A , Schwartzkopf M , Rothkirch A , Roth S V
Published: December 2022

Two recently developed experimental devices for investigating soft matter deformation are presented. Both devices exploit the capabilities of a modern synchrotron beamline to enable advanced and highly precise materials-science experiments in which X-ray scattering is registered. The devices can be operated both in monotonic as well as cyclic mode and are implemented into a beamline at DESY, Hamburg (Germany). Hence, relevant experimental parameters, such as displacement, force and temperature, are recorded synchronously with the individual X-ray scattering patterns. In addition, spatial variation of materials deformation can be monitored and recorded with optical microscopy. This unique sample environment enables in situ X-ray experiments in transmission, i.e. small- or wide-angle X-ray scattering (SAXS or WAXS), and in grazing-incidence geometry, i.e. grazing-incidence (GI-) SAXS or WAXS. One device with stepper motors is designed for studies of slow, (quasi-) static deformation and the other one with pneumatic actuators can be used for fast, impact deformation. Both devices are available to external beamline users, too.
Millisecond-Order Temporal-Resolution Synchrotron X-ray Tomography without Sample Rotation
Authors: Yashiro Wataru , Liang Xiaoyu , Voegeli Wolfgang , Arakawa Etsuo , Shirasawa Tetsuroh , Kajiwara Kentaro , Fujii Katsuya , Hashimoto Koh , Kudo Hiroyuki
Published: December 2022

A multi-beam optics consisting of curved crystals with blades for a white synchrotron X-ray beam from a bending magnet was developed, and millisecond-order temporal-resolution X-ray tomography with a voxel size of 20 μm was successfully realized without sample rotation. The multi-beam optics opens the spatio-temporal frontier of X-ray tomography for unrepeatable and nonequilibrium systems and is expected to be applied to various fields in materials and life sciences.
MOGNO, the nano and microtomography beamline at Sirius, the Brazilian synchrotron light source
Authors: Archilha N L , Costa GS R , Ferreira G R B , Moreno G B Z L , Rocha A S , Meyer B C , Pinto A C , Miqueles E X S , Cardoso M B , Westfahl Jr H
Published: December 2022

The MOGNO beamline is a high-energy imaging beamline dedicated to in situ and operando experiments in heterogeneous and hierarchical samples, and one of the beamlines of the first phase of SIRIUS, the 4th generation storage ring at the LNLS. The beamline is currently under commissioning and will operate at energies of 21.5, 39.0 and 67.7 keV, using as primary source a 3.2T permanent magnet dipole, with critical energy of 19.15 keV. The beam is demagnified down to a nanometric focal spot (≈120 nm) using a set of three elliptical mirrors, which introduces a divergence and, hence, the beamline operates in a cone beam geometry with variable field-of-view (FoV between 150 µm to 85 mm) and spatial resolution (≈120 nm to 55 |am). These conditions are reached with two end-stations, the nanotomography and the microtomography stations. A high-Z photon counting detector, with detection area of ≈85 x 85 mm2, will serve for both the nano and micro-station, but the beamline will also count on an indirect detection system based on a sCMOS camera and a macroscope.