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Article

A Concept of an Educational Multi-Technique Beamline for Crystalline Matter Studies at Synchrotron Radiation Facility SKIF

by
Alexander Selyutin
1,
Denis Mishchenko
1,*,
Zakhar Vinokurov
1,
Olga Bulavchenko
1,
Andrey Saraev
1,
Sergey Tsybulya
2 and
Yan Zubavichus
1
1
Synchrotron Radiation Facility SKIF, 630559 Koltsovo, Russia
2
Department of Physics, Novosibirsk State University, 630090 Novosibirsk, Russia
*
Author to whom correspondence should be addressed.
Crystals 2024, 14(12), 1056; https://doi.org/10.3390/cryst14121056
Submission received: 19 November 2024 / Revised: 2 December 2024 / Accepted: 3 December 2024 / Published: 5 December 2024
(This article belongs to the Section Inorganic Crystalline Materials)
Browse Figures
Versions Notes

Abstract

A concept of a high throughput, user-friendly, versatile bending magnet beamline at the fourth-generation synchrotron radiation facility SKIF, currently being constructed in Koltsovo (a science town near Novosibirsk, Russia), is proposed. The beamline is designed to implement the conventional and most demanded synchrotron techniques: XAS (X-ray absorption spectroscopy); XRD (X-ray diffraction), both powder and single-crystal, including the in situ mode; and XRF (X-ray fluorescence analysis). The beamline is conceived to be as simple as possible, but it is multifunctional, being a base beamline for the education and training of students, future synchrotron users, and beamline scientists. A number of potential beamline optical layouts are modeled in the XRT (XRayTracer) program package. The resulting beam characteristics at the sample position are discussed. A monochromator model is proposed. Surface distortions and their influence on the rocking curve of the Si111 crystal due to incoming heat loads are realistically modeled. The optimum design of the station is defined. The range of crystalline objects that are possible to be studied at the proposed station is emphasized, and future perspectives are outlined.

Graphical Abstract

1. Introduction

1.1. Storage Ring and Synchrotron Radiation Source

The emergence of the fourth-generation synchrotron radiation facilities based on so-called diffraction-limited storage rings (DLSRs) employing multibend-achromat (MBA) magnetic lattices [1] and providing an ultra-low emittance has enabled new research opportunities [2]. Following the beginning of the operation of the first few fourth-generation facilities, namely 3 GeV Max IV in 2016 (horizontal emittance εx = 200–330 pm.rad [3]); 3 GeV Sirius in 2020 (εx = 250 pm.rad [4]); 6 GeV HEPS in 2024 (εx = 34 pm.rad [5]) and 6 GeV ESRF-EBS upgrade in 2020 (εx = 133 pm.rad [6]), 6 GeV APS upgrade in 2024 (εx = 68 pm.rad [7]), various projects of similar facilities have emerged. One of these projects, the 3 GeV fourth-generation synchrotron source, having a low natural emittance εx = 75 pm.rad [8], is a synchrotron facility named SKIF (an acronym of: Siberian Circular Source of Photons in Russian). Currently, as of 2024, SKIF is at the late stages of construction in the science town Koltsovo near Novosibirsk, Russia.
The magnetic lattice of SKIF allows one to utilize a bending magnet (BM) radiation. There are two types of BMs at SKIF. The X-ray radiation source for this particular beamline is chosen to be a hard dipole magnet, with characteristics as presented in Table 1.
The design of the beamline’s front end defines a cone of radiation available for experimental use. The front end contains Be windows with a total thickness of 600 μm. The photon spectrum expected in the optical hutch is presented in Figure 1 (obtained in the program package SPECTRA [9] based on the bending magnet characteristics presented in Table 1). A critical energy of around 12 keV ensures suitable flux for the techniques planned to be implemented at this beamline.
Based on the available flux after the front end, the beamline is planned to be used in the energy range of 3–35 keV.

1.2. The Concept of the Beamline

The upcoming commissioning of the first fourth-generation synchrotron source in Russia unveils new research opportunities. Although there is already an established synchrotron community in Russia [10,11,12,13,14,15], the full capacity of SKIF would include 30 beamlines, each of them possibly having several end stations (branches) served by diamond beamsplitters; thus, the existing synchrotron user community should grow and mature for the facility to be exploited to the fullest extent [16]. So, it is important to train new synchrotron users as well as future beamline scientists rapidly and efficiently. The beamline under consideration is intended for providing a “hands on” experience for novice synchrotron scientists and is paramount for the future growth and development of the SKIF project. Another educational function is to conduct studies for university students, including workshops and laboratory work and research projects of graduate and postgraduate students. It is planned that the beamline will become the basis for additional education programs, such as schools, advanced training courses, and thematic conferences; research remains for solving educational tasks using the beamline facilities [17].
This beamline is planned to become the first in operation at SRF SKIF that dictates the choice of synchrotron radiation generation source and downstream optical devices of the beamline. Therefore, the concept of the beamline described in this paper is optimized according to this purpose.
In summary, this beamline could be commissioned as soon as the storage ring magnet lattice is commissioned. The beamline will implement essential synchrotron techniques for crystalline matter investigation, namely, XAS, XRD (both powder and single-crystal, including the in situ mode), and XRF. This set of techniques requires a wide energy spectrum with a stable flux, which a bending magnet can provide. The main focus of the beamline is to get novice beamline users acquainted with a routine operation of a beamline. Every beamline scientist and user should be familiar with essential optical elements, main synchrotron investigation techniques, and typical beamline equipment (operation of optics and experimental instrumentations). To satisfy the “educational” scope of the beamline, the optical layout is intended to be as simple as possible and is equipped with easily replaceable elements. That is another reason for a bending magnet being the best choice, because of lower requirements for thermal management. Despite the intentional simplicity, high brilliance of the fourth-generation synchrotron source, and versatile end station equipment, the setup still allows numerous scientific investigations of high quality to be performed at this beamline. Also, it is important to have a routinely operated station at the synchrotron source, which covers the demand for mundane scientific research of crystalline matter but at a high quality, which a fourth-generation facility can provide.

1.3. Bending Magnet Beamlines: World-Wide Experience

1.3.1. Beamline Optics Considerations

To reach the best compromise between simplicity and functionality of the beamline, it is necessary to take into account world-wide experience regarding the design of bending magnet beamlines with similar techniques implemented.
Because the radiation from a bending magnet is characterized by a large divergence along with a much lower flux compared with wigglers and undulators, it is important to collect and focus as much of the synchrotron radiation produced as possible. By using large mirrors (>1 m long) to collimate the beam before a crystal monochromator and then focus the beam onto an experimental end station, it is possible to obtain beam parameters comparable with unfocused light from an undulator in terms of spectral flux density and energy resolution [18]. Based on these considerations, a popular bending magnet beamline optical design [19,20,21,22,23] consists of a fixed-exit double-crystal monochromator (often based on Si111 crystals) with a flat bendable collimating mirror before the monochromator in order to reduce the divergence and reach an optimum energy resolution defined only by the Darwin width (i.e., FWHM of the crystal rocking curve) of the monochromator crystals. The second monochromator crystal is usually sagittally bent to focus the beam horizontally; further downstream, a second flat mirror is placed, which can be meridionally bent to focus the beam vertically to the sample position. Sometimes, a pair of small Kirkpatrick–Baez (K–B) mirrors are used for the final focusing of the beam down to the μm (or even nm) range. Mirrors are also used for higher monochromator harmonics rejection by adjusting the type of reflecting surface coating and the angle of radiation incidence. Such an optical scheme ensures the maximum brilliance of the beam obtainable from a bending magnet and deliverable to the fixed sample position, regardless of the photon energy.
Despite the popularity of the aforementioned scheme, collimating and focusing mirror systems of a high quality are notoriously difficult in terms of manufacturing, adjustment, operation, and maintenance [24,25,26], not to mention incurring high cost. Therefore, in some cases, the use of such systems is either minimized or avoided altogether [27].

1.3.2. Experimental Techniques

A wide bending magnet spectrum makes it natural to implement basic XAS techniques as it is relatively easy to scan absorption edges using a simple channel-cut monochromator. To implement the same techniques at undulator-based beamlines, sophisticated equipment and operations are required, including the use of a cryocooled double-crystal monochromator (DCM) packed with sophisticated mechanics for the concerted monochromator crystal movements operated in a feedback loop with a change in the magnetic field of an undulator. Because the basic XAS experiment requires a simple setup (only intensity monitors and/or fluorescence detectors), it is possible to combine it together with XRD (both powder and single-crystal, including simple in situ setups) [22,28,29,30,31] and XRF [32,33,34] on the same end station. The usage of a fixed-exit DCM monochromator allows one to use the same sample position, both when switching between XAS and XRD (XRF) and when switching between different absorption edges. In the case of a simpler channel-cut monochromator system using a large unfocused beam, it is possible to keep the sample at the same position by using close energies for XAS and XRD (XRF). The other option is to vertically (in the case of a vertically reflecting monochromator) adjust the sample position to ensure that the same part of the sample is illuminated when changing the photon energy. But this is difficult as it requires a movement of the whole experimental setup. By combining this set of techniques for a sample in a continuous experiment, it is possible to obtain comprehensive information concerning the state of the sample, including local and long-range order structural information as well as qualitative and quantitative elemental composition.
Taking into account the available energy spectrum (3–35 keV), this will allow access to K absorption edges [35] for elements from K (3.6074 keV) to I (33.1694 keV) and L edges from Pd (L-I: 3.6043 keV), which will address most of the scientific tasks in the fields of catalysis and materials science.

2. Materials and Methods

2.1. The XRT Software Package

Ray tracing simulations, which allowed us to obtain full characteristics of the beam (beam profile, flux, energy resolution, thermal load at optical elements) at any point in the optical train, were performed using the XRT (XRayTracer v. 1.6.0) package [36,37,38]. The XRT package allows one to build almost any beamline based on standardized elements starting from an X-ray source. The XRT package provides a user-friendly GUI that allows one to “build” a beamline and generate a Python script for specialized package codes to perform calculations. Furthermore, the XrtGlow module included to XRT package allows for a 3D visualization of a modeled beamline, which provides an easy way to identify and correct possible mistakes.
The results of simulations using the XRT package have been validated by experimental measurements [39].

2.2. Three-Dimensional Models of Optical Layouts and a Channel-Cut Monochromator

Three-dimensional models were built in FreeCad (v. 1.0.0) software [40]. Renders of 3D models were performed using Blender software (v. 3.6) [41].

2.3. Thermal Calculations

The finite element analysis thermal calculations were performed using FreeCad software with the FreeFem++ solver [42].
All data provided by the software were used as received. The figures presented based on the data obtained via the software were constructed by the authors of this manuscript in such a manner to highlight the important aspects of the calculations.

3. Results

3.1. Optical Layouts (Schemes)

In this work, we have considered several optical assemblies of the beamline to assess the full range of the beamline capabilities, i.e., what (in terms of flux and beam size at the sample position) could be theoretically achieved using different optical arrangements. In order to directly compare optical assemblies between each other, we used the same length of the full optical train (source—sample position distance 49.5 m). The main optical elements (the monochromator, mirrors) were taken with the same characteristics (physical dimensions of optical surfaces). Details will be provided below.
We have considered the following optical schemes (Table 2): Scheme 1 is aimed at using the full advantages of the fourth-generation source (i.e., high brilliance) and constitutes two consecutive mirrors before a channel-cut crystal (Si111) monochromator: one meridionally bent flat mirror for the beam collimation in the vertical direction; and a flat mirror for the rejection of higher monochromator harmonics. Both mirrors are 1 m long. Final focusing of the beam is obtained using two small short-focus elliptical Pt-coated mirrors in the K–B (Kirkpatrick–Baez) geometry.
Scheme 2 is similar to Scheme 1 except that the focusing is performed by means of Be 2D CRLs (compound refractive lenses) positioned at around 1.5 m upstream from the sample.
Scheme 3 is similar to Scheme 2 except for a focusing device. The final beam profile is formed by slits before the sample position.
Scheme 4 reproduces a popular optical arrangement described in Section 1.3.1. (the one with a sagittal focusing monochromator) without the use of K–B mirrors.
Scheme 5 explores the possibility of using a minimum number of optical elements—only a channel-cut monochromator and slits, which is optimal for an educational beamline.
In summary, the idea was to directly compare the beam characteristics that could be theoretically obtained using the chosen synchrotron radiation generation source employing different optical layouts. In order to accomplish that, we kept the full length of an optical train and a monochromator the same (position and design) for each Scheme (except for Scheme 4, in which we have to use a DCM). Over the course of the calculations, we started with the most sophisticated layout, which uses two mirror systems (pair of long mirrors before a crystal monochromator and a K–B mirror system before the sample); after that, we explored the possibility of simplifying the focusing device (by replacing the K–B system by a CRL system, and then by beam-defining slits). Then we compared it with the most efficient and popular layout (Scheme 4, Section 1.3.1). Finally, we compared the actual layout planned to be implemented at the beamline (Scheme 5), which uses only a monochromator and beam-defining slits.

3.2. Characteristics of Main Optical Elements

3.2.1. Collimation and Higher-Harmonics Rejection Mirror System

Schemes 1–4 use a meridionally bent mirror for a white-beam collimation before a monochromator to limit the divergence and improve the energy resolution. The mirror is chosen to be 1 m long, which is a reasonable length in terms of manufacturing, and it is placed at a distance of 22 m from the source. The mirror consists of three optical stripes used for different energy ranges: a 300 Å Pt coating on a Si substrate, a 300 Å Rh coating on a Si substrate, and uncoated Si. The optical surfaces are 20 mm wide to accept the entire incoming beam in the horizontal direction defined by the fixed mask in the front end (horizontal acceptance 0.8 mrad). Surface roughness is taken as 5 Å RMS, which is achievable by a high-end chemical mechanical polishing [43]. The estimated minimum curvature radius required for collimation is 10 km (Table 3).
After the collimating mirror, a higher-harmonics rejecting flat mirror of the same size and optical surfaces is placed at a distance of 24 m from the source right before the monochromator (Schemes 1–3). The angles of incidence on both mirrors are chosen to be the same to keep the beam path straight with only the vertical offset. The use of two mirrors also increases the higher-harmonics rejection capacity. Angles of incidence, radii of curvature for the collimating mirror, and the type of optical surfaces for used energies during calculations are summarized in Table 3 and are chosen based upon squared reflectivity curves for the optical surfaces (Figure 2).
The choice of optimum optical surfaces and angles of incidence are the result of the compromise between the beam acceptance of the mirrors defined by the angle of incidence, value of squared reflectivity, and the requirements to suppress higher harmonics of the monochromator (Si333). The best compromise, providing the maximum flux and allowing a sufficient higher-harmonics suppression, is presented in Figure 2 (black line). In the energy range of 3–8 keV, it is preferable to use the Si optical surface with a glancing angle of incidence ranging from 4.5 mrad to 3.5 mrad. The energy range from 8 to 21 keV is most suited for the Rh coating at glancing angles 3.5–3.0 mrad. It is also viable to avoid the use of the Rh coating by covering the 8–15 keV range with the Si coating (glancing angles 3.0–2.0 mrad) and the 15–21 keV range with the Pt coating (glancing angles 2.5–2.0 mrad). This negatively affects the photon flux in the mid-energy range but makes the mirror setup more cost-effective and simpler to produce.

3.2.2. Monochromator System: Thermal Management

A channel-cut crystal monochromator was chosen as the most appropriate one for this beamline. As this beamline is, first of all, an XAS one, it is important to be able to provide a wide-range energy scanning in a stable and reliable way. A fixed-exit DCM would be a more convenient choice (due to the fixed exit), but such a system would be much more complex and less suited for educational purposes. Strictly speaking, the use of a channel-cut monochromator for XAS in the whole energy range is possible when working with a large beam, i.e., in Schemes 3 and 5. The use of a channel-cut monochromator in the case of submicron focusing will lead to the drift of a beam across the sample during the energy scan, which is highly undesirable. For a vertical channel-cut monochromator with a gap of 8 mm (monochromator–sample distance 23.5 m), a vertical drift of the beam during a typical 1 keV scan is in the range of 1–2 mm at energies below 5 keV, about 50 μm at around 12 keV, and 1–2 μm at energies close to 35 keV (Figure 3). Hence, it is possible to work with micron-sized beams using a channel-cut monochromator at higher energies. Another option is to perform a synchronized movement of the sample during the scan to always illuminate the same area, although it is not easy to implement. Regardless, our calculations also will be applicable in the case of a fixed-exit double-crystal monochromator, provided that its crystals collect the same-sized (as a channel-cut one) incoming beam in the whole energy range.
For maximizing the total flux at the sample position and overall convenience, we chose to use the Si111 crystal for the whole energy range. We considered using the Si311 crystal above 15 keV to improve the energy resolution (Figure 4), but overall flux loss would be unacceptable, and the energy resolution obtainable with Si 111 crystal (Darwin width Δ E E ≈   10−4) is sufficient for basic XAS techniques provided that the mechanics of the monochromator allow for a sufficient energy scanning step, which at energies > 20 keV should be in the range of 2.42–0.97 μrad.
To gather the whole beam in the energy range of 3–35 keV (Bragg angles of 42–3°, rounded) limited by the acceptance of the first mirror, the first channel-cut monochromator crystal needs to be 32 mm long and the second one needs to be 160 mm long. This takes into account the monochromator–source distance of 26 m and the gap between the crystals of 8 mm. Unfortunately, in this case, at 3 keV, the beam will touch the edge of the first crystal after reflection from the second one; therefore, there is a need to cut the first crystal to 30 mm (2 mm from the touched edge), in which case it decreases flux at 35 keV by ~5%, which is tolerable.
Figure 5 shows the 3D model of the channel-cut monochromator visualizing the beam path for the photon energies of 3 keV and 35 keV.
Thermal management is a big concern for optics at the third- and fourth-generation synchrotron radiation facilities. In the case of a BM beamline, it is not as essential compared with the case of undulator- and wiggler-based ones. Regardless, thermal loads at each optical element should be thoroughly estimated to determine the best cooling system for a particular element.
In the case of Scheme 5, which we actually are planning to implement, in order to provide the maximum flux, it would be beneficial to collect as much of the beam as reasonably possible at the monochromator. That means a substantial thermal load at the first monochromator crystal. The thermal load would be ≈50 W at a minimal footprint with a size of 21 × 15 mm2 (across × along beam direction, for the photon energy of 3 keV and Bragg angle of ≈41.24°). Typically, such a high power density (0.16 W/mm2) requires a water-cooled system for the first crystal, although it is quite possible that a passive cooling system might be sufficient.
In order to estimate the thermal impact in the aforementioned case, we considered a uniform irradiation of the corresponding area with the integral power of 50 W. The thickness of a silicon wafer was taken as 10 mm. The silicon wafer was put in a 10 mm thick copper case. Two copper braid wires on each side were placed with a total cross-section area of about 50 × 4 mm2 (48 × 20 × 3/0.15 strands × wire number per strand × layers/single wire diameter, mm), with a length of 160 mm being connected to the surfaces of a vacuum chamber having a constant temperature of 22 °C.
The resulting surface deformation in the case of 50 W of heat load is presented in Figure 6.
The temperature of the irradiated spot rose up to 100 °C, leading to a vertical displacement of the crystal surface by on average +20 μm with some spatial variations (less than 1 μm), presented in Figure 6. Such variations are going to worsen the energy resolution by increasing the rocking curve width of the Si111 crystal as specific parts of the crystal experiencing different displacements will diffract at slightly different angles. The theoretically predicted rocking curves for 3 keV corresponding to an ideal undeformed crystal and in the case of a 50 W thermal load are compared in Figure 7.
A heat load of 50 W would cause close to a 50% increase in the effective rocking curve width of the Si111 crystal, which is a tolerable amount. It should be noted that in the real case, the increase will certainly be larger, as the irradiating beam is not uniform i.e., it possesses a spatial energy distribution plus other various parameters, which were either not accounted for or not accounted for properly during the calculations. Regardless, it is possible to utilize a passive cooling system without crucial flux and energy resolution loss, although water cooling would certainly be a better option. In the future, we are going to switch to Scheme 4, which uses a 1 m long mirror before a monochromator. This will alleviate all thermal load concerns as, according to our calculations, the maximum heat load onto the first monochromator crystal would be less than 14 W.

3.2.3. Focusing and Beam Defining at Sample Position

A final beam-shaping optical element plays an important role in the quality of the beam at the sample position both by influencing the beam profile and total flux. The full details for each particular scheme will be provided in the corresponding sections.
Now, we briefly describe the main characteristics of the considered beam-defining elements.
Scheme 1 relies on a K–B pair of small (active length 100 mm) Pt-coated elliptical mirrors with a surface roughness of 5 Å (RMS). We considered the two glancing angles of incidence in order to maximize the flux (Figure 2)—3.5 mrad for photons up to 20 keV and 2.0 mrad for photons above 20 keV.
Scheme 2 uses a stack of short-focus 2D paraboloid lenses with a web thickness of 30 μm and a radius of curvature of 0.2 or 0.05 mm as the focusing element (values are based on the available commercial offers). Table 4 lists the exact location, characteristics, and number of lenses used in calculations at different photon energies to obtain the focus at the sample position (49.5 m).
The simplest approach to define the final beam profile is to use monochromatic slits before the sample. In the case of Scheme 3, the role of monochromatic slits is only to define the shape and size of the collimated beam at the sample position, as after the monochromator, we obtain a beam with an energy spectrum close to the Si111 crystal rocking curve of the monochromator crystal. In the case of Scheme 5, which does not assume collimation of the beam, the energy spectrum after the monochromator is defined by the convolution of the Si111 crystal rocking curve and the vertical divergence of the incoming beam. In this case, photons of different energy will form a spatial distribution at the sample position. Therefore, by decreasing the vertical size of the monochromatic slits, it would be possible to improve the energy resolution at the expense of photon flux. Further sections will discuss how exactly this simple arrangement compares with the other more sophisticated optical schemes.

3.3. Results of Calculations

3.3.1. Scheme 1

The optical layout of Scheme 1 is presented in Figure 8.
From the general design of this particular layout, we cannot expect a high level of flux at the sample position due to moderately sized mirrors used, but, keeping in mind small source size, we could expect focusing of the beam down to the submicron range. This will open possibilities for the implementation of investigation techniques in the μ-mapping mode (μXAS, μXRD, μXRF).
Regardless of photon energy, we obtained a beam at the sample position with the size of around 100 × 300 nm2 (h × v). Figure 9 shows beam profiles for the photon energies of 9 keV and 25 keV.
Figure 10 shows the efficiency of higher-harmonic rejection in Scheme 1 and the final beam parameters in terms of flux and energy bandwidth.
The flux for each calculated energy point is above 108 ph/s, except for 3 keV. At this energy, the monochromator, in addition to the main first harmonic, lets through a substantial flux of the third harmonic (Si333, 9 keV). Because in the available BM spectrum the amount of 9 keV photons is substantially higher than 3 keV photons (Figure 1), the harmonic rejection mirror has an insufficient rejection factor (≈10−2). In general, using energies lower than 5 keV for this beamline in any configuration is difficult. But it is still possible if the experimental conditions can tolerate either high flux of higher monochromator harmonic or low flux at the main harmonic (employing additional detuning of the second monochromator crystal to increase the rejection factor at the cost of the main harmonic flux). Calculations for other energy points show a tolerable flux with a good higher harmonic rejection level (rejection factor ≈10−3–10−6, 5–27 keV). The energy resolution is slightly lower than calculated from rocking curve widths for Si111 crystal due to non-ideal collimation of the beam before monochromator, but it is still in the order of 10−4 (in terms of Δ E E ), which is the target value for basic XAS techniques.

3.3.2. Scheme 2

The optical layout of Scheme 2 is presented in Figure 11.
CRLs may be a cheaper and easier to adjust, operate, and maintain alternative to a K–B mirror system if one does not require submicron focusing. Figure 12 shows the beam profile obtained for 9 and 25 keV.
Compared with a K–B mirror system, the beam footprint at the sample position for different energy points substantially differs and requires a slightly different position and number of lenses for the best focusing (Table 4). The results of the calculations of the flux and beam sizes are presented in Figure 13.
A flux above 108 ph/s is obtained in the energy range of 5–30 keV. In this energy range, both horizontal and vertical sizes are less than 10 μm. The results show that the CRL focusing system is acceptable for microfocus experiments. Overall, the flux at every energy point is lower than for Scheme 1 (K–B mirror system) due to the smaller optical aperture of the CRLs and absorption in the CRL material (Be). It is worth noting that both changing the distance of the CRL system as well as the number of lenses in the stack substantially affects the size of the focused beam; hence, the final beam size can be manipulated in a broad range, giving this setup the flexibility to handle different sample sizes.

3.3.3. Scheme 3

The optical layout of Scheme 3 is presented in Figure 14.
There are many applications that do not necessarily require a micron-size beam and may even benefit from a larger illumination area and higher photon flux (namely, powder diffraction and XAS). In this case, the use of a final beam-defining slit is sufficient for finalizing the beam parameters at the sample position. Figure 15 shows the photon flux at each chosen energy point with the final slit opening 2 × 2 mm2 and the size of a square slit at which flux will be in the range 1 × 108–5 × 108 ph/s (i.e., comparable with the flux using Scheme 2).
While employing slit 2 × 2 mm2, the photon flux is above 5 × 108 ph/s for each chosen energy point; therefore, in this particular layout, as it was mentioned earlier, it is possible to work at energies of 3–5 keV with a substantial higher-harmonics contamination (see Figure 10) or by employing the second crystal detuning.
Figure 15 also clearly shows why it is more efficient to focus the beam: comparable flux with using the K–B system (Scheme 1) and CRLs (Scheme 2), i.e., 1 × 108–5 × 108 ph/s, is achieved in the case of using slit at much larger beam spots (200–400 μm in the range 5–35 keV). Still, Scheme 3 is obviously directly compatible with Schemes 1 and 2, and one could easily transition between them according to an experimental demand.

3.3.4. Scheme 4

The optical layout of Scheme 4 is presented in Figure 16.
The most frequently employed optical layout at bending magnet beamlines (see Section 1.3.1) is an attempt to have the “best of all worlds”, i.e., an energy width close to the Darwin width of the Si111 crystal (in our case) using beam collimation before a monochromator; we can collect a maximum flux by focusing a monochromatic beam horizontally using a sagittally bent second crystal and then focus vertically using a meridionally focusing mirror placed after the monochromator.
Such an optical layout in our case allows one to obtain a focus point at the sample position 10 × 10–12 × 12 μm2 in the whole working energy range. The required curvature radius of the second crystal is between 16.4 m and 1.4 m, which is achievable by commercial systems. The bending radius for the focusing mirror is between 4 km and 10 km. The beam footprint for 35 keV is presented in Figure 17a. This scheme provides an order of magnitude better flux for each energy point compared with Scheme 3 (2 × 2 mm2 slit); see Figure 17b.
Therefore, the use of such an optical layout could ensure the maximum capabilities of the considered photon source (hard dipole bending magnet at SRF SKIF) and provide the optimum flux at micron-sized beams. Moreover, it is possible to use a pair of small K–B mirrors in this optical layout to further decrease the size the to nm range, losing the flux only at the reflection from mirror surfaces (which would be less than an order of magnitude).

3.3.5. Scheme 5

The optical layout of Scheme 5 is presented in Figure 18.
An educational station implementing basic techniques such as XRD, XAS, and XRF could, in principle, be operated using only two types of optical devices—slits and a monochromator. For a novice synchrotron user and/or scientists, it is the optical elements that they are required to master first. From this point of view, a lack of complicated mirror systems is beneficial as this allows one to concentrate on the essentials of a beamline. Of course, this comes at the expense of the quality of the beam at the sample position. It is exactly the extent of the final beam parameter degradation that we tried to predict and evaluate on the basis of the calculations.
The main obvious loss in the quality of the beam is the energy resolution due to the lack of collimation in the vertical direction of the incoming divergent beam. But, owning to the fact that photons of slightly different energies come out of a monochromator at slightly different angles, it is possible to improve on the energy resolution by cutting the part of the beam in the vertical (in the case of vertical monochromator) direction using slits. So, it is interesting to compare Scheme 3 (which employs two 1 m long mirrors before the monochromator) and Scheme 5, which employ only a monochromator and slits.
While performing calculations for Scheme 5, first of all, for each energy point, we found the vertical size of the slit that provides the best energy resolution (close to the Darwin width of the Si111 crystal), and the use of an even narrower slit does not provide any better energy resolution. Figure 19 shows a comparison of flux at the sample position between Schemes 3 and 5 at slit sizes of 2 × 2 (h × v) and 2 × max.v. (max. v.—size of the vertical slit at which the energy resolution presented in Figure 19 inset is achieved). Scheme 3 provides a higher flux at every energy point, but the difference is not huge: only by a factor of 1.5–2.0. But it is important to remember that Scheme 3 provides such a flux at an energy resolution close to the Darwin width of the Si111 crystal. Such an energy resolution, while using Scheme 5, for photon energies higher than 5 keV comes with a substantial flux loss of up to an order of magnitude for energies close to 35 keV.
As one can see from Figure 19 (inset), it is possible to obtain an energy resolution close to the Si111 crystal Darwin width for 7 keV and above. It is worth noting that, although the FWHM of energy distribution obtained that way is similar to Scheme 3, the profile of the distribution differs (Figure 20). In the case of the collimated beam, the energy distribution has the form of the rocking curve of the Si111 crystal, having a well-defined Darwin width. In the case of cutting the beam by slits, the energy distribution possesses long tails both in the direction of higher and lower energies.
Therefore, it is possible to obtain a decent beam quality at the sample position using only a monochromator and slits. This will allow us to perform routine XAS, XRD, and XRF at the beamline and not only train novice beamline users/scientists but also obtain relevant scientific results as well.

4. Discussion

Overall, our calculations clearly show the advantages and disadvantages of different optical layouts in the case of a bending magnet beamline. For recap, typical characteristics of the beam (size and photon flux) that are expected for each considered optical layout at 3, 12, and 35 keV are presented in Table 5.
The choice of a particular optical layout, first of all, should be consistent with the intended purpose of the beamline, dictated by experimental techniques that are planned to be implemented and the type of samples to be investigated. There is an argument for always striving to achieve the lowest possible beam size with highest photon flux (as in Scheme 4). Such a brilliant beam is absolutely necessary for the implementation of experimental techniques in the μ-mapping mode or for in situ/operando studies with custom-made cells or diamond anvil cell experiments. But for those advanced experiments, it is advisable to choose an undulator as the photon generation source.
In contrast, there are applications that require μm sized beams with a moderate photon flux, where the radiation damage is essential for a sample lifespan, namely, single-crystal diffraction for small organic crystals (or even macromolecular crystallography, provided that a suitable experimental setup is available). In this case, Schemes 1 and 2 (as a cheaper and more convenient option) are suitable as at undulator beamlines, the beam has to be attenuated to prevent a quick burnout of a crystal, while in the case of a bending magnet beamline, it is not obligatory. There are some techniques that benefit from large illumination areas on the sample, namely, classic powder XRD and XAS; for the implementation of these techniques, Scheme 3 would be the optimal scheme as it provides a decent flux (especially at final slit opening > 1 mm) along with an energy resolution close to the Darwin width of the monochromator crystal and a good level of higher-harmonics suppression, which are especially important for the XAS technique.
Based on the above-stated considerations, we opted for Scheme 5 for the first stage of the beamline development. Scheme 5, which uses only a monochromator and slits as optical elements, is the optical layout that we are planning to use at the beamline first commissioning. It is worth noting that such a simple setup will allow us to put the beamline into operation as soon as the first synchrotron radiation beam from the bending magnet is obtained. The use of such a layout will significantly reduce time for the commissioning stage of the beamline, and it will be ready to perform its scientific and educational purposes as the first operational beamline of SRF SKIF. This is also beneficial for obtaining the designed electron beam parameters during the first months of storage ring operation. Moreover, as other beamlines will be commissioned and the local synchrotron radiation community grows, it will require moderate efforts to upgrade the simplistic educational layout of Scheme 5 to the most efficient Scheme 4 and turn this beamline into a high-end scientific instrument serving a wide range of scientific investigations in the field of studying crystalline matter, utilizing all of the benefits of a fourth-generation synchrotron radiation source.

5. Conclusions

In conclusion, this paper outlines a concept for a bending magnet beamline at the upcoming fourth-generation synchrotron source SRF SKIF in the science town Koltsovo, Russia. This beamline is planned to become the first operational one at SRF SKIF. It is conceived to be an educational beamline for students, novice synchrotron users, and beamline scientists. At this beamline, it is planned to implement a number of basic synchrotron techniques for crystalline matter investigation, namely, XAS, XRD (powder and single-crystal), and XRF. These specific features of the beamline dictate the optical layout, which is intentionally made as simple as possible. In the future, it will be upgraded to take full advantage of the fourth-generation source. Overall, we performed ray tracing simulations using the XRT program package to compare the quality of the beam for all of the five optical configurations. The advantages and disadvantages of each optical layout were discussed in detail. The thermal load onto the first monochromator crystal and its influence on the effective energy resolution for Si111 crystal was specifically considered. The results showed that passive cooling could be sufficient and could cause only a moderate broadening of the Si111 rocking curve width. If proven to be successful, the approach of designing beamlines presented herein will be deployed for other SRF SKIF beamlines.

Author Contributions

Conceptualization, A.S. (Alexander Selyutin) and D.M.; data curation, D.M.; formal analysis, D.M.; funding acquisition, Y.Z.; investigation, A.S. (Alexander Selyutin) and D.M.; methodology, A.S. (Alexander Selyutin) and Z.V.; project administration, S.T.; resources, A.S. (Andrey Saraev) and S.T.; supervision, O.B. and A.S. (Andrey Saraev); validation, Z.V. and Y.Z.; visualization, A.S. (Alexander Selyutin) and D.M.; writing—original draft, D.M.; writing—review and editing, A.S. (Alexander Selyutin), Z.V., O.B. and Y.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the Ministry of Science and Higher Education of the Russian Federation (Agreement No. 075-15-2022-263).

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Acknowledgments

The investigations were performed using large-scale research facilities “EXAFS spectroscopy beamline” at the Siberian synchrotron and terahertz radiation center.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Einfeld, D.; Plesko, M. A Modified QBA Optics for Low Emittance Storage Rings. Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrometers Detect. Assoc. Equip. 1993, 335, 402–416. [Google Scholar] [CrossRef]
  2. Li, P.; Allain, M.; Grünewald, T.A.; Rommel, M.; Campos, A.; Carbone, D.; Chamard, V. 4th Generation Synchrotron Source Boosts Crystalline Imaging at the Nanoscale. Light Sci. Appl. 2022, 11, 73. [Google Scholar] [CrossRef] [PubMed]
  3. Tavares, P.F.; Al-Dmour, E.; Andersson, Å.; Cullinan, F.; Jensen, B.N.; Olsson, D.; Olsson, D.K.; Sjöström, M.; Tarawneh, H.; Thorin, S.; et al. Commissioning and First-Year Operational Results of the MAX IV 3 GeV Ring. J. Synchrotron. Rad. 2018, 25, 1291–1316. [Google Scholar] [CrossRef] [PubMed]
  4. Liu, L.; Neuenschwander, R.T.; Rodrigues, A.R.D. Synchrotron Radiation Sources in Brazil. Phil. Trans. R. Soc. A 2019, 377, 20180235. [Google Scholar] [CrossRef] [PubMed]
  5. Jiao, Y.; Xu, G.; Cui, X.-H.; Duan, Z.; Guo, Y.-Y.; He, P.; Ji, D.-H.; Li, J.-Y.; Li, X.-Y.; Meng, C.; et al. The HEPS Project. J. Synchrotron. Rad. 2018, 25, 1611–1618. [Google Scholar] [CrossRef]
  6. Raimondi, P. ESRF-EBS: The Extremely Brilliant Source Project. Synchrotron Radiat. News 2016, 29, 8–15. [Google Scholar] [CrossRef]
  7. Henderson, S. Status of the APS Upgrade Project. In Proceedings of the 6th International Particle Accelerator Conference, Richmond, VA, USA, 3–8 May 2015. IPAC2015; 3p. [Google Scholar] [CrossRef]
  8. Baranov, G.; Bogomyagkov, A.; Morozov, I.; Sinyatkin, S.; Levichev, E. Lattice Optimization of a Fourth-Generation Synchrotron Radiation Light Source in Novosibirsk. Phys. Rev. Accel. Beams 2021, 24, 120704. [Google Scholar] [CrossRef]
  9. Tanaka, T. Major Upgrade of the Synchrotron Radiation Calculation Code SPECTRA. J. Synchrotron. Rad. 2021, 28, 1267–1272. [Google Scholar] [CrossRef]
  10. Piminov, P.A.; Baranov, G.N.; Bogomyagkov, A.V.; Berkaev, D.E.; Borin, V.M.; Dorokhov, V.L.; Karnaev, S.E.; Kiselev, V.A.; Levichev, E.B.; Meshkov, O.I.; et al. Synchrotron Radiation Research and Application at VEPP-4. Phys. Procedia 2016, 84, 19–26. [Google Scholar] [CrossRef]
  11. Zolotarev, K.V.; Ancharov, A.I.; Vinokurov, Z.S.; Goldenberg, B.G.; Darin, F.A.; Kriventsov, V.V.; Kulipanov, G.N.; Cooper, K.E.; Legkodymov, A.A.; Lyubas, G.A.; et al. Synchrotron Radiation Based Research at the Novosibirsk Scientific Center. Bull. Russ. Acad. Sci. Phys. 2023, 87, 541–551. [Google Scholar] [CrossRef]
  12. Anashin, V.V.; Valentinov, A.G.; Veshcherevich, V.G.; Vobly, P.D.; Gavrilov, N.G.; Gorniker, E.I.; Zubkov, N.I.; Korchuganov, V.N.; Kuzminykh, V.S.; Kulipanov, G.N.; et al. The Dedicated Synchrotron Radiation Source Siberia-2. Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrometers Detect. Assoc. Equip. 1989, 282, 369–374. [Google Scholar] [CrossRef]
  13. Chernyshov, A.A.; Veligzhanin, A.A.; Zubavichus, Y.V. Structural Materials Science End-Station at the Kurchatov Synchrotron Radiation Source: Recent Instrumentation Upgrades and Experimental Results. Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrometers Detect. Assoc. Equip. 2009, 603, 95–98. [Google Scholar] [CrossRef]
  14. Lazarenko, V.; Dorovatovskii, P.; Zubavichus, Y.; Burlov, A.; Koshchienko, Y.; Vlasenko, V.; Khrustalev, V. High-Throughput Small-Molecule Crystallography at the ‘Belok’ Beamline of the Kurchatov Synchrotron Radiation Source: Transition Metal Complexes with Azomethine Ligands as a Case Study. Crystals 2017, 7, 325. [Google Scholar] [CrossRef]
  15. Svetogorov, R.D.; Dorovatovskii, P.V.; Lazarenko, V.A. Belok/XSA Diffraction Beamline for Studying Crystalline Samples at Kurchatov Synchrotron Radiation Source. Cryst. Res. Technol. 2020, 55, 1900184. [Google Scholar] [CrossRef]
  16. Bukhtiyarov, A.V.; Bukhtiyarov, V.I.; Zhuravlev, A.N.; Zolotarev, K.V.; Zubavichus, Y.V.; Levichev, E.B.; Mezentsev, N.A.; Nikolenko, A.D.; Piminov, P.A.; Churkin, I.N. Synchrotron Radiation Facility “Siberian Circular Photon Source” (SRF SKIF). Crystallogr. Rep. 2022, 67, 690–711. [Google Scholar] [CrossRef]
  17. Bulavchenko, O.A.; Vinokurov, Z.S.; Selyutin, A.G.; Mishchenko, D.D.; Saraev, A.A.; Goldenberg, B.G.; Tsybulya, S.V.; Zubavichus, Y.V. Concept Design of the CCU Skif–NSU Experimental Station 1-7 “Basic Methods of Synchrotron Diagnostics for Educational, Research, and Innovative Activities of Students”. J. Struct. Chem. 2023, 64, 1329–1340. [Google Scholar] [CrossRef]
  18. Lang, J.C.; Srajer, G.; Wang, J.; Lee, P.L. Performance of the Advanced Photon Source 1-BM Beamline Optics. Rev. Sci. Instrum. 1999, 70, 4457–4462. [Google Scholar] [CrossRef]
  19. Karapetrova, E.; Ice, G.; Tischler, J.; Hong, H.; Zschack, P. Design and Performance of the 33-BM Beamline at the Advanced Photon Source. Nucl. Instrum. Methods Phys. Res. Sect. A Accel. Spectrometers Detect. Assoc. Equip. 2011, 649, 52–54. [Google Scholar] [CrossRef]
  20. Chahine, G.A.; Blanc, N.; Arnaud, S.; De Geuser, F.; Guinebretière, R.; Boudet, N. Advanced Non-Destructive in Situ Characterization of Metals with the French Collaborating Research Group D2AM/BM02 Beamline at the European Synchrotron Radiation Facility. Metals 2019, 9, 352. [Google Scholar] [CrossRef]
  21. Solari, P.L.; Schlutig, S.; Hermange, H.; Sitaud, B. MARS, a New Beamline for Radioactive Matter Studies at SOLEIL. J. Phys. Conf. Ser. 2009, 190, 012042. [Google Scholar] [CrossRef]
  22. Belin, S.; Briois, V.; Traverse, A.; Idir, M.; Moreno, T.; Ribbens, M. SAMBA a New Beamline at SOLEIL for XRay Absorption Spectroscopy in the 440keV Energy Range. Phys. Scr. 2005, 980. [Google Scholar] [CrossRef]
  23. Rebuffi, L.; Plaisier, J.R.; Abdellatief, M.; Lausi, A.; Scardi, P. MCX: A Synchrotron Radiation Beamline for X-ray Diffraction Line Profile Analysis. Z. Anorg Allge Chem. 2014, 640, 3100–3106. [Google Scholar] [CrossRef]
  24. Siewert, F. Metrology, Mirrors and Gratings—Advances and Challenges in Synchrotron Optics. J. Phys. Conf. Ser. 2013, 425, 152001. [Google Scholar] [CrossRef]
  25. Reyes-Herrera, J.; Celestre, R.; Cammarata, M.; Barrett, R.; Levantino, M.; Sanchez Del Rio, M. X-Ray Beam Quality after a Mirror Reflection: Experimental and Simulated Results for a Toroidal Mirror in a 4th Generation Storage-Ring Beamline. Open Res. Eur. 2023, 3, 173. [Google Scholar] [CrossRef]
  26. Yamauchi, K.; Mimura, H.; Matsuyama, S.; Yumoto, H.; Kimura, T.; Takahashi, Y.; Tamasaku, K.; Ishikawa, T. Focusing Mirror for Coherent Hard X-Rays. In Synchrotron Light Sources and Free-Electron Lasers; Jaeschke, E., Khan, S., Schneider, J.R., Hastings, J.B., Eds.; Springer International Publishing: Cham, Switzerland, 2015; pp. 1–26. ISBN 978-3-319-04507-8. [Google Scholar]
  27. Kropf, A.J.; Katsoudas, J.; Chattopadhyay, S.; Shibata, T.; Lang, E.A.; Zyryanov, V.N.; Ravel, B.; McIvor, K.; Kemner, K.M.; Scheckel, K.G.; et al. The New MRCAT (Sector 10) Bending Magnet Beamline at the Advanced Photon Source; American Institute of Physics: Melbourne, VIC, Australia, 2010; pp. 299–302. [Google Scholar]
  28. Park, C.; Popov, D.; Ikuta, D.; Lin, C.; Kenney-Benson, C.; Rod, E.; Bommannavar, A.; Shen, G. New Developments in Micro-X-Ray Diffraction and X-Ray Absorption Spectroscopy for High-Pressure Research at 16-BM-D at the Advanced Photon Source. Rev. Sci. Instrum. 2015, 86, 072205. [Google Scholar] [CrossRef]
  29. Briois, V.; La Fontaine, C.; Belin, S.; Barthe, L.; Moreno, T.; Pinty, V.; Carcy, A.; Girardot, R.; Fonda, E. ROCK: The New Quick-EXAFS Beamline at SOLEIL. J. Phys. Conf. Ser. 2016, 712, 012149. [Google Scholar] [CrossRef]
  30. Dent, A.J.; Cibin, G.; Ramos, S.; Smith, A.D.; Scott, S.M.; Varandas, L.; Pearson, M.R.; Krumpa, N.A.; Jones, C.P.; Robbins, P.E. B18: A Core XAS Spectroscopy Beamline for Diamond. J. Phys. Conf. Ser. 2009, 190, 012039. [Google Scholar] [CrossRef]
  31. Fabiani, S.; Ahangarianabhari, M.; Baldazzi, G.; Bellutti, P.; Bertuccio, G.; Bruschi, M.; Bufon, J.; Carrato, S.; Castoldi, A.; Cautero, G.; et al. Development and Tests of a New Prototype Detector for the XAFS Beamline at Elettra Synchrotron in Trieste. J. Phys. Conf. Ser. 2016, 689, 012017. [Google Scholar] [CrossRef]
  32. Fodje, M.; Grochulski, P.; Janzen, K.; Labiuk, S.; Gorin, J.; Berg, R. 08B1-1: An Automated Beamline for Macromolecular Crystallography Experiments at the Canadian Light Source. J. Synchrotron. Rad. 2014, 21, 633–637. [Google Scholar] [CrossRef]
  33. Feng, R.; Dolton, W.; Igarashi, R.; Wright, G.; Bradford, M.; McIntyre, S.; Garrett, R.; Gentle, I.; Nugent, K.; Wilkins, S. Commissioning of the VESPERS Beamline at the Canadian Light Source; American Institute of Physics: Melbourne, VIC, Australia, 2010; pp. 315–318. [Google Scholar]
  34. Baudelet, F.; Belkhou, R.; Briois, V.; Coati, A.; Dumas, P.; Etgens, V.H.; Flank, A.M.; Fontaine, P.; Garreau, Y.; Lyon, O.; et al. Soleil a New Powerful Tool for Materials Science. Oil Gas Sci. Technol. Rev. IFP 2005, 60, 849–874. [Google Scholar] [CrossRef]
  35. Bearden, J.A.; Burr, A.F. Reevaluation of X-Ray Atomic Energy Levels. Rev. Mod. Phys. 1967, 39, 125–142. [Google Scholar] [CrossRef]
  36. Klementiev, K.; Chernikov, R. Powerful Scriptable Ray Tracing Package Xrt.; Sanchez Del Rio, M., Chubar, O., Eds.; SPIE: San Diego, CA, USA, 5 September 2014; p. 92090A. [Google Scholar]
  37. Klementiev, K.; Chernikov, R.; Rakitin, M. Kklmn/Xrt: Release 1.6.0. 2023. Available online: https://github.com/kklmn/xrt/releases/tag/1.6.0 (accessed on 4 November 2024).
  38. Klementiev, K.; Chernikov, R. New Features of Xrt: Bent Crystals, Coherent Modes, Waves with OAM. Synchrotron Radiat. News 2023, 36, 23–27. [Google Scholar] [CrossRef]
  39. Kahnt, M.; Klementiev, K.; Haghighat, V.; Weninger, C.; Plivelic, T.S.; Terry, A.E.; Björling, A. Measurement of the Coherent Beam Properties at the CoSAXS Beamline. J. Synchrotron. Rad. 2021, 28, 1948–1953. [Google Scholar] [CrossRef] [PubMed]
  40. Hennes, C. The FreeCAD Open Source Project. Available online: https://github.com/FreeCAD/FreeCAD (accessed on 4 November 2024).
  41. The Blender 3.6 Manual by the Blender Documentation Team. Available online: https://docs.blender.org/manual/en/3.6/index.html (accessed on 4 November 2024).
  42. Frederic Hecht Freefem++ Manual (Release 4.13). Available online: https://doc.freefem.org/pdf/FreeFEM-documentation.pdf (accessed on 4 November 2024).
  43. Jiang, B.; Zhao, D.; Wang, B.; Zhao, H.; Liu, Y.; Lu, X. Flatness Maintenance and Roughness Reduction of Silicon Mirror in Chemical Mechanical Polishing Process. Sci. China Technol. Sci. 2020, 63, 166–172. [Google Scholar] [CrossRef]
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Figure 1. Photon flux in a working energy range of the beamline provided by the bending magnet. Black line—after fixed mask 0.8/0.4 mrad, no filter. Red line—same mask, but with a 600 μm Be filter.
Figure 1. Photon flux in a working energy range of the beamline provided by the bending magnet. Black line—after fixed mask 0.8/0.4 mrad, no filter. Red line—same mask, but with a 600 μm Be filter.
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Figure 2. Squared reflectivity curves for the Si (a), Rh (b), and Pt (c) optical surfaces at different glancing angles of incidence.
Figure 2. Squared reflectivity curves for the Si (a), Rh (b), and Pt (c) optical surfaces at different glancing angles of incidence.
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Figure 3. Displacement of the beam in the vertical direction caused by the channel-cut monochromator considered in this work.
Figure 3. Displacement of the beam in the vertical direction caused by the channel-cut monochromator considered in this work.
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Figure 4. Squared maximum reflectivity (R2) and Darwin width for the Si111 and Si311 crystals.
Figure 4. Squared maximum reflectivity (R2) and Darwin width for the Si111 and Si311 crystals.
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Figure 5. Beam path through the channel-cut monochromator: for the photon energy of 3 keV on the left; for the photon energy of 35 keV on the right.
Figure 5. Beam path through the channel-cut monochromator: for the photon energy of 3 keV on the left; for the photon energy of 35 keV on the right.
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Crystals 14 01056 g006
Figure 6. First monochromator crystal Si111 surface displacement under irradiation with a total power of 50 W at Bragg angle ≈ 41.24°.
Figure 6. First monochromator crystal Si111 surface displacement under irradiation with a total power of 50 W at Bragg angle ≈ 41.24°.
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Figure 7. Rocking curves for Si111 crystal under 0 and 50 W heat loads due to irradiation at 3 keV.
Figure 7. Rocking curves for Si111 crystal under 0 and 50 W heat loads due to irradiation at 3 keV.
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Figure 8. Optical layout of Scheme 1. BM—Bending magnet; FM—fixed mask with 600 μm Be windows; WS1, WS2—white beam slits; CM—collimating mirror; RM—higher-harmonics rejecting mirror; CrM—crystal monochromator; MS—monochromatic slit; K–B—Kirkpatrick–Baez mirror system.
Figure 8. Optical layout of Scheme 1. BM—Bending magnet; FM—fixed mask with 600 μm Be windows; WS1, WS2—white beam slits; CM—collimating mirror; RM—higher-harmonics rejecting mirror; CrM—crystal monochromator; MS—monochromatic slit; K–B—Kirkpatrick–Baez mirror system.
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Figure 9. Beam profiles obtained for Scheme 1 at photon energies of 9 keV on the left and 25 keV on the right.
Figure 9. Beam profiles obtained for Scheme 1 at photon energies of 9 keV on the left and 25 keV on the right.
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Figure 10. Flux of the main monochromatic beam (Si111) and third-order (Si333) harmonic for Scheme 1. Calculated Δ E E via ray tracing and theoretical Darwin width Δ E E for Si111 crystal (see Figure 4).
Figure 10. Flux of the main monochromatic beam (Si111) and third-order (Si333) harmonic for Scheme 1. Calculated Δ E E via ray tracing and theoretical Darwin width Δ E E for Si111 crystal (see Figure 4).
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Figure 11. Optical layout of Scheme 2. BM—Bending magnet; FM—fixed mask; WS1, WS2—white beam slits; CM—collimating mirror; RM—higher-harmonics rejecting mirror; CrM—crystal monochromator; MS—monochromatic slit; CRLs—compound refractive lenses.
Figure 11. Optical layout of Scheme 2. BM—Bending magnet; FM—fixed mask; WS1, WS2—white beam slits; CM—collimating mirror; RM—higher-harmonics rejecting mirror; CrM—crystal monochromator; MS—monochromatic slit; CRLs—compound refractive lenses.
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Figure 12. Beam profiles obtained for Scheme 2 at photon energies of 9 keV on the left and 25 keV on the right.
Figure 12. Beam profiles obtained for Scheme 2 at photon energies of 9 keV on the left and 25 keV on the right.
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Figure 13. The results of the calculations for Scheme 2: flux and beam size at the sample position obtained for the CRL configuration presented in Table 4.
Figure 13. The results of the calculations for Scheme 2: flux and beam size at the sample position obtained for the CRL configuration presented in Table 4.
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Figure 14. Optical layout of Scheme 3. BM—Bending magnet; FM—fixed mask; WS1, WS2—white beam slits; CM—collimating mirror; RM—higher-harmonics rejecting mirror; CrM—crystal monochromator; FS—final slit (beam defining).
Figure 14. Optical layout of Scheme 3. BM—Bending magnet; FM—fixed mask; WS1, WS2—white beam slits; CM—collimating mirror; RM—higher-harmonics rejecting mirror; CrM—crystal monochromator; FS—final slit (beam defining).
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Figure 15. The results of the calculations for Scheme 3: flux for slit 2 × 2 mm2; minimal size of a square-shaped slit required to obtain flux in the range of 1 × 108–5 × 108 ph/s.
Figure 15. The results of the calculations for Scheme 3: flux for slit 2 × 2 mm2; minimal size of a square-shaped slit required to obtain flux in the range of 1 × 108–5 × 108 ph/s.
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Figure 16. Optical layout of Scheme 4. BM—Bending magnet; FM—fixed mask; WS1, WS2—white beam slits; CM—collimating mirror; SBCrM—sagittally bent monochromator crystal; VFM—vertically focusing mirror.
Figure 16. Optical layout of Scheme 4. BM—Bending magnet; FM—fixed mask; WS1, WS2—white beam slits; CM—collimating mirror; SBCrM—sagittally bent monochromator crystal; VFM—vertically focusing mirror.
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Figure 17. The results of the calculations for Scheme 4: (a) footprint of the beam at a sample position for a photon energy of 35 keV; (b) the flux (ph/s) at the sample position.
Figure 17. The results of the calculations for Scheme 4: (a) footprint of the beam at a sample position for a photon energy of 35 keV; (b) the flux (ph/s) at the sample position.
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Figure 18. Optical layout of Scheme 5. BM—Bending magnet; FM—fixed mask; WS1, WS2—white beam slits; CrM—crystal monochromator; FS—final slit (beam defining).
Figure 18. Optical layout of Scheme 5. BM—Bending magnet; FM—fixed mask; WS1, WS2—white beam slits; CrM—crystal monochromator; FS—final slit (beam defining).
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Figure 19. The results of the calculations for Scheme 5. Comparison of the photon flux between Schemes 3 and 5 employing different final slits. The inset shows the energy resolution obtainable for Scheme 3 and for Scheme 5 using a vertical slit denoted as a hollow square.
Figure 19. The results of the calculations for Scheme 5. Comparison of the photon flux between Schemes 3 and 5 employing different final slits. The inset shows the energy resolution obtainable for Scheme 3 and for Scheme 5 using a vertical slit denoted as a hollow square.
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Figure 20. Energy distribution in the case of a collimated beam (green) and the same energy resolution obtained for a non-collimated beam (blue), 12 keV.
Figure 20. Energy distribution in the case of a collimated beam (green) and the same energy resolution obtained for a non-collimated beam (blue), 12 keV.
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Table 1. Characteristics of the SKIF hard dipole magnet.
Table 1. Characteristics of the SKIF hard dipole magnet.
CharacteristicValue
Magnetic field, T2.05
Critical energy, keV11.97
Beta function βx/βy, m0.252/7.77
Size of the source h/v, μm14.14/24.14
Acceptance 1 h/v, mrad0.8/0.4
1 Defined by a fixed mask in the front end.
Table 2. List of optical elements for each considered scheme.
Table 2. List of optical elements for each considered scheme.
Collimation and Higher-Harmonics RejectionMonochromatizationFinal Beam Shaping (Focusing)
Scheme 1 A meridionally bent mirror (collimation): 1 m long, 22 m from source, 3 stripes (Si, Rh, Pt—200 mm wide)
A flat mirror (higher monochromator harmonics rejection): 1 m long, 24 m from source, 3 stripes (Si, Rh, Pt—200 mm wide). Vertically reflecting.		A channel-cut crystal (Si111) vertically reflecting monochromator: 1st crystal 30 mm long; 2nd crystal 160 mm long; gap 8 mm; 26 m from sourceA K–B mirror system: two elliptical mirrors with 100 mm active lengths. First horizontal: 49.08 m from source; 2nd vertical: 49.2 m from source
Scheme 2 A stack of 2D Be-focusing double paraboloid lenses: around 48 m from source
Scheme 3 Beam-defining slits: 48 m from source
Scheme 4 A meridionally bent mirror (collimation): 1 m long, 22 m from source, 3 stripes (Si, Rh, Pt—200 mm wide). Vertically reflecting.A fixed-exit double-crystal monochromator. Vertically reflecting.A sagittally bent 2nd crystal of the monochromator. A meridionally bent mirror: 1 m long, 40 m from source, 3 stripes (Si, Rh, Pt—200 mm wide). Vertically reflecting.
Scheme 5 -A channel-cut crystal (Si111) vertically reflecting monochromator: 1st crystal 30 mm long; 2nd crystal 160 mm long; gap 8 mm; 26 m from sourceBeam-defining slits, 48 m from source
Table 3. Types of optical surfaces, glancing angles of incidence, and radii of curvatures for the collimating mirror used in the calculations.
Table 3. Types of optical surfaces, glancing angles of incidence, and radii of curvatures for the collimating mirror used in the calculations.
Energy, keVOptical SurfaceGlancing Angle of Incidence, mradRadius of Curvature for Collimating Mirror, km
3Si4.510
5Si3.015
7Si2.519
9Si2.022
12Si2.022
15Si2.022
20Rh2.022
25Pt2.022
30Pt2.022
35Pt2.022
Table 4. Types of optical surfaces, glancing angles of incidence, and radii of curvature for the collimating mirror used in calculations.
Table 4. Types of optical surfaces, glancing angles of incidence, and radii of curvature for the collimating mirror used in calculations.
Energy, keVDistance from Source, mmNumber of LensesRadius of Curvature, mmGeometric Aperture, mm
348,16020.21
548,01350.21
748,29030.050.5
947,99640.050.5
1247,95470.050.5
1547,975110.050.5
2047,930190.050.5
2548,045320.050.5
3048,000450.050.5
3548,050650.050.5
Table 5. Characteristics of the beam at the sample position for the optical layouts at some energy points.
Table 5. Characteristics of the beam at the sample position for the optical layouts at some energy points.
Flux (ph/s)Size (h × v FWHM, μm2)
Schemes 1–3 (flux before monochromator after mirrors/after monochromator)3 keV: 1.4 × 1011/2.8 × 1010-
12 keV: 8.5 × 1011/4.5 × 1011
35 keV: 2.8 × 1011/1.5 × 1011
Scheme 1 (mirrors, K–B)3 keV: 1.8 × 1073 keV: 0.1 × 0.3
12 keV: 6.1 × 10812 keV: 0.1 × 0.3
35 keV: 8.4 × 10735 keV: 0.1 × 0.3
Scheme 2 (mirrors, CRLs)3 keV: 9.3 × 1063 keV: 2.4 × 5.0
12 keV: 3.8 × 10812 keV: 3.0 × 2.4
35 keV: 6.7 × 10735 keV: 10.4 × 18.5
Scheme 3 (mirrors, slit)3 keV: 7.6 × 1082000 × 2000
12 keV: 2.6 × 1010
35 keV: 8.8 × 109
Scheme 4 (mirrors, sag. monochromator)3 keV: 7.6 × 1093 keV: 10.0 × 10.0
12 keV: 2.4 × 101112 keV: 12.0 × 12.0
35 keV: 7.4 × 101035 keV: 10.0 × 10.0
Scheme 5 (no mirrors, slit)3 keV: 7.1 × 1083 keV: 2000 × 3000
12 keV: 4.2 × 10912 keV: 2000 × 600
35 keV: 7.1 × 10835 keV: 2000 × 250
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Selyutin, A.; Mishchenko, D.; Vinokurov, Z.; Bulavchenko, O.; Saraev, A.; Tsybulya, S.; Zubavichus, Y. A Concept of an Educational Multi-Technique Beamline for Crystalline Matter Studies at Synchrotron Radiation Facility SKIF. Crystals 2024, 14, 1056. https://doi.org/10.3390/cryst14121056

AMA Style

Selyutin A, Mishchenko D, Vinokurov Z, Bulavchenko O, Saraev A, Tsybulya S, Zubavichus Y. A Concept of an Educational Multi-Technique Beamline for Crystalline Matter Studies at Synchrotron Radiation Facility SKIF. Crystals. 2024; 14(12):1056. https://doi.org/10.3390/cryst14121056

Chicago/Turabian Style

Selyutin, Alexander, Denis Mishchenko, Zakhar Vinokurov, Olga Bulavchenko, Andrey Saraev, Sergey Tsybulya, and Yan Zubavichus. 2024. "A Concept of an Educational Multi-Technique Beamline for Crystalline Matter Studies at Synchrotron Radiation Facility SKIF" Crystals 14, no. 12: 1056. https://doi.org/10.3390/cryst14121056

APA Style

Selyutin, A., Mishchenko, D., Vinokurov, Z., Bulavchenko, O., Saraev, A., Tsybulya, S., & Zubavichus, Y. (2024). A Concept of an Educational Multi-Technique Beamline for Crystalline Matter Studies at Synchrotron Radiation Facility SKIF. Crystals, 14(12), 1056. https://doi.org/10.3390/cryst14121056

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