Search

The demand to improve the efficiency of precious metal trade has been increasing of late. Due to its non-destructive nature, energy-dispersive X-ray fluorescence has the potential to supplant the fire assay procedure. Improved accuracy in the measurement of gold purity can be achieved by optimizing the X-ray fluorescent signal by selecting a suitable collimator beam size. Four homogenous materials with different alloy matrix of gold-certified reference were investigated. The effects of collimator beam sizes on the accuracy of gold purity evaluation were observed. The findings can be treated as the foundation to improve the accuracy of gold purity measurement with X-ray fluorescence.

Fragmentation and the subsequent heat transfer from solvated gold nanoparticles with sizes 50, 100, 150, and 250 nm to water are studied by time-resolved shadowgraph photography. The measured fragm...

Fiber-reinforced concrete (FRC) is a concrete restrain fibrous material which increases its structural integrity. There are various types of fiber available like natural fiber, artificial fiber. The real contribution of the fiber is to increase the hardness of the concrete under any type of loading. Fiber-reinforced concrete is most familiar in India, but structural applications are very much limited. The FRC used for heavy-duty industrial floors. The fiber reinforced concrete is used in tunneling projects and for slope stabilization in India. To analyze the physical and mechanical properties of fiber mixed concrete by a lab test. In this project, the M30 concrete mix is used and the beam size used 1400 mm * 200 mm in size.

In order to overcome space limitations, a novel method is introduced to measure the focal point size of a sagittally bent Laue crystal monochromator by using a multi-hole array. Combined with ray-tracing measurements, the focal length and focused beam size were determined. Theoretical simulations and experiments were performed to demonstrate the feasibility of this method. The experimental results show that this method can provide a fast way of measuring the focusing characteristics of a sagittally bent Laue crystal monochromator.

ALFABURST has been searching for Fast Radio Bursts (FRBs) commensally with other projects using the Arecibo L-band Feed Array (ALFA) receiver at the Arecibo Observatory since July 2015. We describe the observing system and report on the non-detection of any FRBs from that time until August 2017 for a total observing time of 518 hours. With current FRB rate models, along with measurements of telescope sensitivity and beam size, we estimate that this survey probed redshifts out to about 3.4 with an effective survey volume of around 600,000 Mpc$^3$. Based on this, we would expect, at the 99% confidence level, to see at most two FRBs. We discuss the implications of this non-detection in the context of results from other telescopes and the limitation of our search pipeline. During the survey, single pulses from 17 known pulsars were detected. We also report the discovery of a Galactic radio transient with a pulse width of 3 ms and dispersion measure of 281 pc cm$^{-3}$, which was detected while the telescope was slewing between fields., 11 pages, 11 figures, accepted to MNRAS

We report initial observations of coherent optical transition radiation interferometry (COTRI) patterns generated by microbunched electrons from laser-driven plasma accelerators (LPAs). These are revealed in the angular distribution patterns obtained by a CCD camera with the optics focused at infinity, or the far-field, viewing a Wartski two-foil interferometer. The beam divergences deduced by comparison to results from an analytical model are sub-mrad, and they are smaller than the ensemble vertical beam divergences measured at the downstream screen of the electron spectrometer. The transverse sizes of the beamlet images were obtained with focus at the object, or near field, and were in the few-micron regime as reported by LaBerge et al. The enhancements in intensity are significant relative to incoherent optical transition radiation (OTR) enabling multiple cameras to view each shot. We present two-foil interferometry effects coherently enhanced in both the 100-TW LPA at 215 MeV energy at Helmholtz-Zentrum Dresden-Rossendorf and the PW LPA at 1.0-GeV energy at the University of Texas-Austin. A transverse emittance estimate is reported for a microbunched beamlet example generated within the plasma bubble., 5 pp

A two-lens optical system entails two beams: a crossover beam and a Kohler illumination beam. We observed that upon varying the excitation corresponding to the first lens from large to small values, the crossover beam changed to a Kohler illumination beam with increased brightness. We derived new calculation formulas for the Kohler illumination beam. Brightness B and beam current Ib can be expressed as B = Bco (ϕco/ϕ)2 and Ib = Bco (παϕco)2/4, where Bco, ϕco, ϕ, and α denote the crossover beam brightness, crossover beam size, Kohler illumination beam size, and beam semi-angle, respectively; additionally, ϕco and ϕ are obtained at the same first lens excitation. These two equations were experimentally validated. We obtained a brightness of 2.05 × 108 A/cm2 sr using a beam energy and an emission current of 20 keV and 54 µA, respectively. Notably, this value surpasses the Langmuir limit of 4.11 × 105 A/cm2 sr by 499 times.

Recently much attention has been paid to microbeam and minibeam irradiations, present interest focusing on their use in study of the behaviour of single cells, groups of cells, also their application in spatially fractionated radiotherapy. Synchrotrons are the most common source for microbeam radiotherapy (MRT), albeit limited in access and typically offering photon energies very much lower than familiar in the practice of conventional radiotherapy. In this study of feasibility, the design has been investigated of a collimator coupled to a conventional 60Co gamma-irradiator sample chamber to produce a minibeam. MCNPX code Monte Carlo simulations were used to model a Gammacell 220 60Co irradiator with lead and tungsten collimators. The dose profile was evaluated in the absence and presence of the collimator, seeking to optimize collimator design. The results pertain to specific shapes of lead and tungsten collimators producing narrow (millimeter dimension) beams, sufficient in thickness but yet still fitting within the sample chamber, with a peak-to-valley dose ratio (PVDR) greater than 15. The beam size can be tailored with modification in the size of the perforated part, the collimator optimized to minimize the dose-rate at points away from the collimator centre. However the dose-rate at the centre is reduced to between 2 to 20% of that in the absence of collimator. The findings of this study encourage the development of minibeam collimator for gamma irradiators, useful for preclinical minibeam radiotherapy research in centres with little or no access to other appropriate sources.

A 50-m/40-Gb/s 680-nm vertical-cavity surface-emitting laser (VCSEL)-based free-space optical (FSO) communication employing three-stage injection-locked technique and the afocal scheme is proposed and experimentally demonstrated. The three-stage injection-locked technique, which can significantly increase the resonant frequency of the VCSEL, is expected to provide higher transmission rate in FSO communication. The afocal scheme, which can reduce the beam size of laser beam, is expected to provide longer free-space link in FSO communication. As far as we know, it is the first time that a three-stage injection-locked 680-nm VCSEL transmitter and afocal scheme that will successfully build up a 50-m/40-Gb/s FSO communication has been employed. Such a 50-m/40-Gb/s FSO communication provides the advantages of optical wireless links for longer transmission distance and higher transmission rate, which is thoroughly useful for high-speed light-based WiFi (LiFi) applications.

Robotic stereotactic radioablation (RSR) therapy for breast tumors has been shown to be an effective treatment strategy when applied concomitantly with chemotherapy, with the purpose of reducing the tumor volume thus making it more amenable for breast conserving surgery. In this paper we used Monte Carlo simulation within a realistic patient model to determine the influence that the variation in beam collimation radius has on the resultant absorbed dose distributions for this type of treatment. Separate optimized plans were obtained for treatments using 300 circular beams with radii of 0.5 cm, 0.75 cm, 1.0 cm and 1.5 cm. Cumulative dose volume histograms were obtained for the gross, clinical and planning target volumes as well as for eight organs and structures at risk. Target coverage improves as the collimator size is increased, at the expense of increasing the volume of healthy tissue receiving mid-level absorbed doses. Interestingly, it is found that the maximum dose imparted to the skin is highly dependent on collimator size, while the dosimetry of other structures, such as both the ipsilateral and contralateral lung tissue are basically unaffected by a change in beam size.

We report on the progress of the thermal noise further reduced method via enlarging the equivalent beam size without increasing the cavity length in cavity-stabilized lasers at 1555 nm, which are built as the frequency source for a photonic microwave generation system. In addition, we perform an experiment to evaluate the effect of thermal noise reduced method via estimating the frequency instability of a synthesized new ultrastable laser. The relative frequency instability reaches 5∗10−16 at 1 s averaging time via reducing the thermal noise of the cavity.

In this paper, the far-field diffraction pattern of a CGH under a reconstruction beam with a beam area smaller than device area of CGH is investigated. A series of beam size is simulated. It is found that the contrast of diffraction pattern will be increased as an increasing area of the reconstruction beam.

A new method to measure the Twiss parameters in a beam transport line is presented. Usually these parameters are obtained based on the measured beam sizes. In the new method, in contrast, we determine them by finding quadrupole strengths that result in minimum beam sizes at a downstream measurement location. Therefore, systematic errors related to beam-size monitors do not propagate to the measured Twiss parameters. We describe the method together with a detailed estimation of statistical and systematic errors. It was examined with beam at the SwissFEL injector test facility at PSI, and these results are also presented.

An analytical approach describing properties of focused partially coherent X-ray beams is presented., An analytical approach describing properties of focused partially coherent X-ray beams is presented. The method is based on the results of statistical optics and gives both the beam size and transverse coherence length at any distance behind an optical element. In particular, here Gaussian Schell-model beams and thin optical elements are considered. Limiting cases of incoherent and fully coherent illumination of the focusing element are discussed. The effect of the beam-defining aperture, typically used in combination with focusing elements at synchrotron sources to improve transverse coherence, is also analyzed in detail. As an example, the coherence properties in the focal region of compound refractive lenses at the PETRA III synchrotron source are analyzed.

We demonstrate a novel nonlinear optical super-oscillatory lens, i.e. a periodically poled LiTaO 3 nonlinear photonic crystal, to create an optical needle with a sub-diffraction beam size of 0.43λ SH and an ultra-long length of 40λ SH .

We have developed Yb:YAG thin-disk multi-pass amplification system adopting image relay to keep the beam size on the thin-disk constant. By this system pulse energy amplification to > 20 mJ was demonstrated.

The Diamond Light Source synchrotron uses active bimorph mirrors to vary X-ray beam size from

The Accelerator Test Facility 2 (ATF2) is an extension of the ATF beamline extraction featuring an ILC-type final focus system. Among the project's major purposes are establishment of hardware and beam handling technologies aimed at transverse focusing of ATF's electron beam to below 40 nm in the vertical. A laser-interferometer type high resolution beam size monitor named the “Shintake Monitor” is installed at ATF2's virtual interaction point, and plays a crucial role in achieving this aim. A laser interference fringe is formed by crossing two coherent laser rays. This functions as an interaction target for probing the electron beam. Beam size sensitivity of the monitor depends on the pitch of the interference fringe, and maximizes at about one fifth of the pitch. The Shintake Monitor at ATF2 is designed to be capable of measuring beam sizes ranging from 6 μm down to 20 nm in the vertical. A vertical beam size of approximately 300 nm has been measured during the run of May 2010. For this running period, ATF2 operated under a special optics configuration with ten times the nominal IP beta function. For the most recent run, due to switching beam optics back to nominal, BG levels rose about 10 times from May. Shintake Monitor had been proven in May to fulfill expectations provided BG is low. However with high BG, its accuracy decreased, which makes low S/N a major concern. In this paper, we describe the design and current status of the Shintake Monitor.

Using a waveguide-type sideband-separating receiver (2SB receiver) on the Tokyo-NRO 60-cm telescope (renamed the AMANOGAWA telescope), we carried out simultaneous observations in the 12CO(J = 2-1) and 13CO(J = 2-1) lines over the Galactic plane l = 10-245 deg along b = 0 deg with a 3.75 arcmin grid. Using the 12CO(J = 1-0) data of Dame et al. (2001), who used a beam size almost the same as ours, we show 12CO(J = 2-1)/12CO(J = 1-0) and 13CO(J = 2-1)/12CO(J = 2-1) intensity ratios on the l-v map and the intensity correlations among the three lines. As a result, a linear correlation between 12CO(J = 1-0) and 12CO(J = 2-1) and a curve correlation between 12CO(J = 2-1) and 13CO(J = 2-1), as produced by most of the data, are found. We investigate these correlations with simple radiative transfer equations to ascertain a number of restrictions on the physical quantities of molecular gas on a galactic scale., 22 pages, 13 figures, accepted for publication in PASJ

The knowledge of the light fluence rate distribution inside a biological tissue irradiated by a Laser (or LED) is fundamental to achieve medical treatments. In this paper, we present a semi-analytical model based on the 2-D Fourier Transform of the diffusion equation. This method can be applied to any irradiation source (cylindrically symmetric or not) at the surface of the tissue. Two particular beam shapes are studied: planar irradiation and flat beam with finite radius. The total fluence rate along the depth in tissues was computed by adding the collimated and the diffuse components. The analytical solution was also used to study the effect of the beam radius on the light attenuation. Measurements were performed using a tank filled with a liquid-simulating medium (Milk), illuminated with a LED array (660 nm, 100mm×100mm). Several circular diaphragms were used to obtain uniform circular beams with well defined radii. An optical fibre (with an isotropic tip) was used to measure the fluence rate inside the medium. Preliminary experimental results are in agreement with theoretical predictions.; International audience; The knowledge of the light fluence rate distribution inside a biological tissue irradiated by a Laser (or LED) is fundamental to achieve medical treatments. In this paper, we present a semi-analytical model based on the 2-D Fourier Transform of the diffusion equation. This method can be applied to any irradiation source (cylindrically symmetric or not) at the surface of the tissue. Two particular beam shapes are studied: planar irradiation and flat beam with finite radius. The total fluence rate along the depth in tissues was computed by adding the collimated and the diffuse components. The analytical solution was also used to study the effect of the beam radius on the light attenuation. Measurements were performed using a tank filled with a liquid-simulating medium (Milk), illuminated with a LED array (660 nm, 100mm×100mm). Several circular diaphragms were used to obtain uniform circular beams with well defined radii. An optical fibre (with an isotropic tip) was used to measure the fluence rate inside the medium. Preliminary experimental results are in agreement with theoretical predictions.

Synchrotron radiation-induced X-ray emission is now a proven analytical method for the determination of trace elements. Better insight of the role of trace elements in tissue samples can be gained by acquiring complete distribution maps of these elements. Our approach is based on the acquisition of digital maps. In this contribution we present two difierent methods for obtaining normalization matrix: flrst | based on argon intensity in the single spectrum and second | based on changes of beam current intensity. The region for the scan was carefully chosen according to the histological view of the sample. A total area was scanned with a step size of 15 „m in each direction and measuring time of 30 s per pixel. The thickness of the samples was 15 „m. A polycapillary was used for beam focusing. At the energy of 18 keV the beam size on the sample was approximately 15 „m which is of the order of a cell diameter.

A planar x-ray waveguide (WG) consisting of a diamond-like carbon layer sandwiched between two Ni layers is used to demonstrate for the first time the possibility of using WGs as optical elements with standard laboratory sources. The exit beam profile for the first two guided modes has been measured and analysed to demonstrate the high degree of beam coherence. The exit divergence and the beam size are reported and compared with theoretical predictions. Other relevant parameters, such as efficiency and gain, have been measured. This opens up interesting perspectives for the production of nanometre-sized x-ray beams with table-top laboratory sources.

The new generation of the intense X-rays sources based on low energy electron storage ring and Compton scattering (CS) of laser beam allows to produce X-rays with intensity up to 10 14 phot/s. There are two basic problems in laser-electron storage rings (LESR) design. The first one is associated with strong effect of the intrabeam scattering at low electron beam energy. Because of this effect the beam size grows quickly and CS intensity decreases. The second problem is associated with large electron beam energy spread because of fluctuation of Compton generation. The value of the energy spread may run up to few percents and one needs to keep electron beam during long term in order to achieve the high Compton beam intensity. The paper is devoted to the description of lattice of NSC KIPT Compact Intense X-ray generator NESTOR and the main principles are background for the LESR lattice design.

It is well known that the electron beam emittance can be lowered by keeping positive dispersion in the insertion straight section of an otherwise double bend achromat lattice. But the fact that the beam size at the straight section is not simply determined by the emittance any more has made the scheme suspicious. There was even a claim that the minimum electron beam size in the straight section remains unchanged regardless of the dispersion. It is shown in this article that the electron beam size can really be decreased by the positive dispersion of the straight section. It is also shown that the minimum of σ 2 / β of the dispersive straight section is 0.64 of that of the minimum double bend achromat lattice.

We present position-velocity strip maps of the Galactic center region in the CO J ¼ 7 ! 6a ndJ ¼ 4 ! 3 transitions observed with the Antarctic Submillimeter Telescope and Remote Observatory located at the Amundsen-Scott South Pole Station. Emission from the two rotational transitions of 12 CO was mapped at b ¼ 0 � for 3=5 > l > � 1= 5o n a1 0 grid with a FWHM beam size of 58 00 at 806 GHz and 105 00 at 461 GHz. Previous observations of CO J ¼ 4 ! 3 (C. L. Martin et al., in preparation) and of [C i] emission (Ojha et al.) from this region show that these lines are distributed in a manner similar to CO J ¼ 1 ! 0 (Stark et al.); the (CO J ¼ 4 ! 3)/(CO J ¼ 1 ! 0) line ratio map is almost featureless across the entire Galactic center region. In contrast, the CO J ¼ 7 ! 6 emission from the Galactic center is strongly peaked toward the Sgr A and Sgr B molecular complexes. A large velocity gradient analysis shows that, aside from the two special regions Sgr A and Sgr B, the photon-dominated regions within a few hundred parsecs of the Galactic center are remarkably uniform in mean density and kinetic temperature at n ¼ 2500–4000 cm � 3 and T ¼ 30–45 K. The (CO J ¼ 7 ! 6)/(CO J ¼ 4 ! 3) line temperature ratios near Sgr B are a factor of 2 higher than those observed in the nuclear region of the starburst galaxy M82 (Mao et al.), while the CO(J ¼ 7 ! 6)/ CO(J ¼ 4 ! 3) line temperature ratios around Sgr A are similar to M82. The line ratio on large scales from the Galactic center region is an order of magnitude less than that from M82. Subject headings: Galaxy: abundances — Galaxy: center — ISM: general — ISM: molecules — submillimeter

In 2007, the General Medicine and Cancer Institutes Collaborative Access Team (GM/CA CAT, Sector 23, Advanced Photon Source) began providing mini-beam collimators to its users. These collimators contained individual, 5- or 10-μm pinholes and were rapidly exchangeable, thereby allowing users to tailor the beam size to their experimental needs. The use of these collimators provided a reduction in background noise, and thus improved the signal-to-noise ratio [1] , [2] . Recent improvements in the collimator design include construction of the device from a monolithic piece of molybdenum with multiple pinholes mounted inside [3] . This allows users to select from various size options from within the beamline control software without the realignment that was previously necessary. In addition, a new, 20-μm pinhole has been added to create a “quad-collimator”, resulting in greater flexibility for the users. The mini-beam collimator is now available at multiple crystallographic beamlines and also is a part of the first Mossbauer Microscopic system at sector 3-ID.

This study investigates the total ionizing dose effect in static random access memory (SRAM)-based field programmable gate array (FPGA). In addition to gamma ray whole-chip irradiation, focused synchrotron x-ray irradiation with beam size of 20 mu m is also used. As a result, the most vulnerable inner circuit in the SRAM-based FPGA is determined directly. Circuit simulation is also executed to understand the failure phenomenon further. The simulated results are consistent with the experimental results.

We describe a direct method for monitoring the geometrical dimensions of a synchrotron beam at the target position for internal target installations. The method allows for the observation of the proton beam size as well as the position of the beam relative to the target. As a first demonstration of the technique, we present results obtained by means of the COSY-11 detection system installed at the cooler synchrotron COSY. The influence of the stochastic cooling on the COSY proton beam dimensions is also investigated., 7 pages, 8 figures, Submitted to Nucl. Inst. & Meth. A

A quasi-optical system consisting of a quasi-optical antenna and two ellipsoidal mirrors can convert the gyrotron output (TE15 mode, 354GHz) into a gaussian-like beam. The waist size of the beam produced is adjusted by moving a second ellipsoidal mirror. The second mirror with focal length of 520mm offers a tunable range from 2.0mm to 5.4mm, and those with focal lengths of 1190mm and 2390mm offer other tunable ranges from 5.1mm to 12.9mm and from 12.0mm to 25.1mm, respectively.

Observations of relativistic beam focusing by a passive plasma lens have demonstrated a reduction in focusing strength due to plasma return current. A 50 MeV beam was propagated through a 1--3 cm long plasma with density around ${10}^{14}{\mathrm{cm}}^{\ensuremath{-}3}$. Beam size was measured as a function of propagation distance. For a ratio of collisionless plasma skin depth to beam spot size ${k}_{p}{\ensuremath{\sigma}}_{r}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.33$, no significant reduction in focusing was observed. Reduced focusing was measured for ${k}_{p}{\ensuremath{\sigma}}_{r}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.1$, where a significant fraction of the inductively driven return current in the plasma flows within the beam. The observations are in good agreement with an envelope equation model and with particle-in-cell simulations.

A combined system of a polycapillary focusing X-ray lens (PFXRL) and a cylindrical polycapillary collimator (CCC) is proposed to obtain a quasi-parallel X-ray microbeam from an ordinary X-ray source. The orders of magnitude of the beam size, gain of power flux density, and divergence of the quasi-parallel X-ray microbeam are 10 μm, 102, and milliradian, respectively.

A multilayer (sputtered-sliced) Fresnel zone plate (FZP) is one of promising focusing optics for high-energy X-rays. In order to attain high diffraction efficiency, two types of multilevel-type multilayer FZPs have been fabricated, and these focusing characteristics have been measured at SPring-8. The FZPs composed of concentric multilayers of alternating high-Z(Cu), low-Z(Al), and several types of composite materials layers by Cu and Al. As a result, (1) no significant difference was observed both the measured beam size and the diffraction efficiency of a FZP during 9 months to the FZP with 4-step structure, (2) the diffraction efficiency of the 1st order focus and the focused beam size measured by the knife-edge scanning were more than 50% and 0.8 μm at 41.3 keV, respectively to the FZP with 6-step structure.

The lattice of the MAX-I electron storage ring has been investigated and tuned towards small momentum compaction values. By measurements of the synchrotron frequency, bunch length, horizontal beam size and beam movement, the beam has been found to behave in reasonable agreement with the predictions of the lattice model up to second order in energy deviation. Both longitudinal and horizontal emittance could be varied within a relatively large range with lattice changes and/or controlled beam energy changes.

Develops an understanding of the energy delivery system and determines how the scanning speed and part strength are affected by particular scanning parameters. Describes a high speed process workstation incorporating a variable beam spot size. Presents a more accurate sintering model which can be used to speed up the scanning process.

Electron beam welding (EBW) has been developed for many years and is being increasingly implemented in various industrial applications. Joining dissimilar metals using EBW has also been a subject of interest in recent years. Due to special features of EBW, e.g., high energy density and accurately controllable beam size and location, in many cases it has proven to be an efficient way of joining dissimilar metals. Numerous successful results have been achieved, and some of them have already been exploited in production. EBW continues to be the subject of investigations and further development, and improvements in the joining of dissimilar metals remains one of the aims. This paper reviews the state-of-the-art EBW of dissimilar metals, with special emphasis on showing the potential of the process for achieving high-quality dissimilar-metal joints. Since EBW is a fusion-welding process, metallurgical phenomena associated with fusion still exist and cause difficulties. However, these are often minor as compared to those in conventional are welding. Problems encountered and possible solutions are discussed. The survey indicates that although many studies have been performed, there is still a considerable need to further examine existing and new combinations. Therefore, future R&D trends are highlighted.

A very simple pinhole camera set-up has been built to diagnose the electron beam emittance of the ESRF. The pinhole is placed in the air next to an Al window. An image is obtained with a CCD camera imaging a fluorescent screen. The emittance is deduced from the size of the image. The relationship between the measured beam size and the electron beam emittance depends upon the lattice functions alpha, beta and eta, the screen resolution, pinhole size and photon beam divergence. The set-up is capable of measuring emittances as low as 5 pm rad and is presently routinely used as both an electron beam imaging device and an emittance diagnostic.

A focusing neutron lens using glass polycapillary fibers has been introduced successfully into a prompt gamma activation analysis (PGAA) instrument placed at the exit of a cold neutron guide. The neutron current density gain of the lens is 80, averaged over the focused beam size of 0.53 mm diameter. PGAA measurements have been made on submillimeter particles of gadolinium and cadmium. The results indicate that elemental sensitivities of measurements are increased by ∼ 60, and that particles of sizes smaller than 0.5 mm can be discerned using the focusing lens. The measured gain in prompt gamma signals for these particles is less than anticipated, probably due to alignment difficulties. Gamma ray background associated with the lens is discussed and improvements are suggested.

The latest revolution in macromolecular crystallography was incited by the development of dedicated, user friendly, micro-crystallography beamlines. Brilliant X-ray beams of diameter 20 microns or less, now available at most synchrotron sources, enable structure determination from samples that previously were inaccessible. Relative to traditional crystallography, crystals with one or more small dimensions have diffraction patterns with vastly improved signal-to-noise when recorded with an appropriately matched beam size. Structures can be solved from isolated, well diffracting regions within inhomogeneous samples. This review summarizes the technological requirements and approaches to producing micro-beams and how they continue to change the practice of crystallography.

Obtaining sub-20 nm lithography is not straightforward, even using a good tool with a sub-5 nm beam size. In this section, a brief overview of the various topics that will be covered in more depth in the rest of the chapter is given.

The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with the purpose to reach a 37nm vertical beam size at the interaction point. In the nanometer beam size regime, higher order multipoles in magnets become a crucial point for consideration. The strength and rotation angle of the ATF2 QEA magnets were reconstructed from measurements done in IHEP in the past and compared with more recent ones from KEK. Based on a sensitivity study, we report on the analysis of possible strategies to mitigate the effects of the measured multipoles. A suggestion is given which will benefit the ATF2 present commissioning to reach the nominal beam size, and also to facilitate the implementation of the reduced β optics in the future.

As-p18, an unusual fatty-acid-binding protein from a parasitic nematode, was expressed in bacteria, purified and crystallized. The use of a microfocus beamline was essential for data collection., As-p18 is a fatty-acid-binding protein from the parasitic nematode Ascaris suum. Although it exhibits sequence similarity to mammalian intracellular fatty-acid-binding proteins, it contains features that are unique to nematodes. Crystals were obtained, but initial diffraction data analysis revealed that they were composed of a number of ‘microdomains’. Interpretable data could only be collected using a microfocus beamline with a beam size of 12 × 8 µm.

Based on a massively parallel beam writing strategy (BACUS 2010) a mask writer proof-of-concept tool was realized in 2011. The eMET (electron Mask Exposure Tool) POC column is designed to provide ca. 262-thousand (512 x 512) programmable beams of 50 keV energy and 20 nm or 10 nm beam size. The total beam current through the column is up to 1 μA. The eMET POC is equipped with a laser-interferometer controlled stage for exposure of one cm2 test pattern fields on 6" mask blanks. Operating the eMET POC with a stencil plate, first exposure results are presented. The further eMET POC project plan and the roadmap for eMET Alpha, Beta and multi-generational HVM tools are outlined.

The influence of laser beam size on laser-induced damage performance, especially damage probability and laser-induced damage threshold (LIDT) is investigated. It is found that damage probability is beam size dependent when various damage precursors with different potential behaviors are involved. This causes damage probability and LIDT are different between tested under large-aperture beam and under small-aperture beam. Moreover, fluence fluctuations of large-aperture laser beam bring about hot spots moving randomly across the beam from shot to shot. Thus it leads to the most probable maximum fluence after many shots at any location across components is several times the average beam fluence. These two effects result in difference of damage performance of components in large-aperture lasers and in small-aperture lasers.

The ATF2 project is the final focus system prototype for the ILC and CLIC linear collider projects, with a purpose of reaching a 37 nm vertical beam size at the interaction point (JP). During the initial commissioning, we started with larger-than-nominal beta-functions at the IP in order to reduce the effects from higher-order optical aberrations and thereby simplifying the optical corrections needed. We report on the simulation studies at two different IP locations developed based on waist scan, dispersion, coupling and beta function multiknobs correction in the large beta optics of ATF2, in the presence of two kinds of magnet inaccuracies (quadrupole gradient and roll errors) to generate all possible linear optic distortions at the IP. A vertical beam size which is very close to the nominal beam size is obtained based on the simulation study.