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We developed a software program to imitate the color of an object within the range of sRGB on a PC display. The obtained colors were converted from the picture information taken under a white light source, such as D65. Other, arbitrary light sources such as natural sunlight or standard illuminants, could be used in addition to the test illumination. Judging from the sample of the converted pictures, the software functions quite well.

Here, we propose a color barrier-free illumination consisting of white, red, and blue LEDs for people with deuteranopia-type defects in color perception. Color perceptions of 20 volunteers with normal vision and four examinees of deuteranopia were evaluated by both the Ishihara test for color blindness and the Farnsworth Panel D-15 test under color barrier-free illumination. The illumination was comparably effective, not only for discriminating between red and green but also for discrimination of the hues on a color chip continuously. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 218–223, 2015

本稿では、私たちが日常生活で目にする印刷物や標識の見え方が、カラーユニバーサルデザインに配慮したデザインが大事だといわれている今日、実態はどのように配慮されているかについて検討している。急速に進展する国際化社会では、視覚表示は文字よりピクトグラムの方が情報を得やすい。また、これらを着色すると人目を引くとの考えから、多くの見る対象が着色されている。 一方、色覚に障害を有する人は日本人の男性では5%弱が先天性赤緑色覚異常で、白人男性の場合は約8%の人が色覚に障害を持つといわれている。更に、我が国は急激な高齢者社会を迎え、文字の細部の識別が困難であるばかりでなく、色彩の識別に問題を抱える人々が増加している社会環境にある。色覚障害についての研究は、個人の色覚判別用の石原式色覚検査表は広く知られている。また、実用を考えた色覚異常による色の見え方についての報告、公共施設の色彩計画について、色覚に関する色覚障害者の見え方への配慮等についての研究は、精力的に発表されている。 色覚に関する基礎研究が大きな成果をあげている中で、これらの成果が実際にはどのように反映されているのか、色覚に障害のある人と色覚に障害のない人が、実際にどのように着色した物を見ているかについて検討したので報告する。

We have been fabricated the multilayer Fresnel zone plate (FZP) for hard X-ray focusing. The multilayer FZP consists of a series of concentric multilayer of low-Z (Al) zone and high-Z (Cu) zone, alternatively. The spatial resolution of the multilayer FZP is related with the outermost zone width and the smoothness of the multilayer. In case of the concentric multilayer FZP, the undulations were often observed. The smoothness of the multilayer is strongly related with he optical resolution. In this study we reported the microscopic structure of the multilayer FZP with a scanning transmission electron microscope (STEM) observation and discussed the seed of the undulation.

We have developed a multilevel-type multilayer X-ray lens (Fresnel zone plate, FZP) using sputter deposition. Such a multilevel-type FZP can attain high diffraction efficiency which results in the reduction of radiation damage to biological specimens and the simplification of the X-ray optical system because unwanted diffraction orders are considerably suppressed. Previously, we have reported the effectiveness (i.e., realizing high diffraction efficiency) of a multilevel multilayer FZP with 4-step structure. This paper presents two experimental results on the FZP: (1) the focusing test of a multilayer FZP with 6-step structure in order to realize higher efficiency and (2) the change over time of the focusing characteristic of the FZP with 4-step structure. For (1), the diffraction efficiency of the 1st order focus and the focused beam size measured by knife-edge scanning were found to be more than 50% and 0.8 μm, respectively, at 41.3 keV, and superior to the previous results. For (2), no significant differences have been observed: it can be said that the multilevel FZP is stable at least for 9 months.

Fluorine-containing indium tin oxide (F-ITO) sputtering targets were prepared using spark-plasma-sintering (SPS) process. The initial powder, which was prepared by reacting ITO with HF, was sintered to the 10 cm-disks with nearly 90% of the theoretical density by the SPS process. The resulting disks were consisted of ITO and InOF, and the fluorine content was about 4 at.%. Using the F-ITO disks as sputtering target, thin films were deposited on the glass substrates. The electrical conductivity and optical transmission of the deposited films were comparable to those of the conventional ITO films, while the surface roughness of the films was much improved.

A multilayer (sputtered-sliced) Fresnel zone plate (FZP) is one of the promising focusing optics with high spatial resolution for the high-energy X-ray region. This is because a large “aspect ratio” can be realized easily. In addition, it is important that the kinoform FZP (theoretical diffraction efficiency=100%) can be fabricated by the sputtered-sliced method. This paper presents the experimental results of two new approaches for fabrication of a multilayer FZP for X-rays. (1) To achieve higher diffraction efficiency, a multilevel-type (4-step: quasi-kinoform type) FZP was fabricated. This FZP was composed of concentric multilayers of alternating high-Z, low-Z, and composite materials. The composite material layer was deposited by co-sputtering of high-Z and low-Z materials. (2) To achieve smoother zones (multilayer interfaces) at the conventional-type FZP, each target of a sputtering apparatus with two DC-sputtering guns was surrounded by a cover with an aperture, and Ar gas was supplied inside the cover, which led to the deposition at lower Ar gas pressure. As a result, for the former, the efficiency was improved markedly as compared with conventional FZP, and for the latter, the zone roughness was reduced, which has resulted in the improvement of the spatial resolution of the FZP.

Three new types of optical elements for the synchrotron radiation (SR) high-brilliance X-ray beamlines have been developed: (1) a spatial resolution test pattern for X-ray computed tomography (CT), (2) a spatial resolution test pattern for X-ray scanning microscopy, and (3) a condenser device for X-ray imaging microscopy. These optical elements are composed of concentric multilayers of alternating high-Z and low-Z material deposited on a wire substrate. The characteristics of these elements have been tested at the SR facilities of Super Photon ring-8 GeV.Optical element (1) yielded a pattern of alternating opaque and transparent concentric rings with a film thickness of 1 μm. For (2), the test pattern was shown to work well in the high-energy X-ray region at 28 keV.Use of the condenser device with optical element (3) produced an absorption contrast image of a test pattern without modulation by the coherence of the source. These optical elements may play important roles in the future development of various analytical areas with high spatial resolution in the high-energy X-ray region at the SR high-brilliance X-ray beamlines.

Microfocusing of 100 keV x ray with a sputtered-sliced Fresnel zone plate (ss-FZP) has been performed at the 250-m-long beamline (20XU) of SPring-8. The ss-FZP with an outermost zone width 0.16 μm which is composed of 70 layers of alternating Cu and Al layers and having thickness ∼180 μm was fabricated and characterized. The minimum focal spot size attained for the first order focal beam was 0.5 μm with a focal distance 900 mm at a photon energy 100 keV. The total flux of the microprobe was ∼2×106 photons s−1 μm−2.

Development of microfocusing optics for scanning microscopy and image forming optics for imaging microscopy are now in progress in SPring-8 by using varieties of optical devices: refractive lens, total reflection mirrors. Fresnel zone plates, and sputtered-sliced Fresnel zone plates. Spatial resolution of 100 nm has been achieved in scanning microscopy using highly coherent X-ray beam at a 248 m-long beamline 20XU and F2P' focusing optics. Recent results on development of optical systems are described.

We are planning to develop a kinoform zone plate (ZP) for hard X-ray using a sputtered-sliced (SS) method with two materials (Cu/Al). The SS kinoform ZP is composed of a Cu/Al multilayer that is based on radial modulation of the refractive indices of deposition materials. The X-ray through the zones interferes constructively at the focal point. The kinoform ZP, therefore, has an advantage of high focusing efficiency. According to the our theoretical calculation, the focusing efficiency of the Cu/Al kinoform PZP is up to 86% in the 0-30 keV X-ray energy region, while one of the conventional Cu/Al multilayer Fresnel zone plate is up to 38%.

Concentric multilayers of alternate high-Z material and low-Z one, deposited on the wire substrate, can be applied to various optical elements for synchrotron radiation (SR) high-brilliance X-ray beamlines. We present new application of the concentric multilayer to optical elements for the SR high-brilliance X-ray beamlines at SPring-8. Three types of Cu/ Al concentric multilayer samples have been fabricated and applied to (1) a spatial resolution test pattern for X-ray computed tomography (CT), (2) a spatial resolution test pattern for the X-ray equipment and (3) a condenser device in the X-ray imaging microscopy. These characteristics have been tested. For the (1), alternate opaque and transparent concentric ring pattern with 2 micron film thickness has been clearly resolved. For the (2), the test pattern can work well in the high energy X-ray region. For the (3), absorption contrast image of a test pattern without modulation by the coherence of the source has been obtained by using the condenser device.

A hard X-ray microbeam is a key technology for third-generation high-brilliance synchrotron radiation sources such as SPring-8. A Fresnel zone plate (FZP) is one of the promising focusing elements for X-rays. A multilayer (sputtered–sliced) FZP is suitable for use in hard X-ray region, because large thickness can be available. Zone (multilayer interface) roughness is inevitable to the multilayer FZP, which results in the inferior-focusing characteristic. Some Cu/Al concentric multilayers were fabricated by DC sputtering deposition. In order to reduce the oblique incidence of sputtered atoms on the wire substrate, a cylindrical slit was placed between the target and the wire substrate. As a result, the interface roughness was improved with very good repeatability.

A zone plate for hard X-rays with outermost zone width as small as 30 nm and thickness ∼14 μm fabricated by sputtered-sliced technology was evaluated. With the brilliant X-ray beam from the undulator at the SPring-8 the minimum focal spot size attained was ∼0.8 μm at the energy of 18.6 keV. The intrinsic diffraction efficiency was determined to be ∼12%.

X-ray imaging microscopy with a sputtered-sliced Fresnel zone plate (SS-FZP) has been developed at an X-ray energy of 25keV. Objects were imaged in transmission with the SS-FZP as an objective with a magnification of 10.2 times, and detected with a X-ray image sensor. The performance of the imaging microscope has been tested with a gold mesh and a resolution test pattern at an undulator beamline 47XU of SPring-8. The resolution test patterns up to 0.5mm line-and-space structures have been resolved. # 2001 Elsevier Science B.V. All rights reserved.

X線集光素子の1つである多層膜フレネルゾーンプレート (FZP) の作製方法, 開発したFZPを利用した集光実験の成果および関連分野の世界の研究動向を紹介した.大型放射光施設SPring-8における集光実験ではトップレベルのデータが得られ, 多層膜FZPは特に高エネルギー領域 (>25keV) の集光にも有効であることがわかった.FZPは連続100時間以上の使用の間, 放射線損傷は観察されなかった.このことから, 高輝度放射光を利用した硬X線顕微鏡の実用化に大きく前進したと言える.測定された性能値を理論値に限りなく近づけるためには, 成膜工程を中心に一層の工夫が必要である.今後, ゾーン (多層膜界面) の平滑性を改善するために成膜条件の検討, 成膜装置の改良を引き続き行うと共に, 多層膜FZPの結像特性の理論的考察も行いたい.また, マイクロビームを利用して微小領域の元素マッピング, 化学状態のイメージングなどを行う予定である.本報告で紹介した以外にも注目すべき新しい硬X線領域用の集光素子が最近相次いで発表され, 今後の進展が期待される.集光テストを行ったSPring-8での利用研究課題の課題番号は, 1999A0091-NM-np, 1999B0080-CM-np, 1999B0103-NM-np, 2000AO160-NM-npである.

The Fresnel zone plate (FZP) is a type of lens for focusing X-rays. We have fabricated a kinoform style FZP with a 30-step structure composed of concentric multilayer of alternating Cu layer, Al layer, and 28 composite material (Cu, Al) layers. The multilayer was deposited using a magnetron sputtering apparatus with two DC-sputtering guns. The focusing characteristics were evaluated at the synchrotron radiation beamline of SPring-8, and the focused beam size measured by knife-edge scanning was 0.8 μm at 40 keV. The peak diffraction efficiencies measured using ion chambers for 1st- and 2nd-order diffraction were 42% and 12% at 40 keV and 20 keV, respectively. High-order X-ray diffraction was also examined using the data obtained from a CCD camera.

A hard X-ray microbeam with submicrometer spot size from third-generation high brilliance synchrotron radiation (SR) sources is expected to be a powerful tool for various fields of research. A Fresnel zone plate (FZP) is one of the promising, focusing elements for X-rays. Focusing efficiency is one of the important features of the FZP. In order to fabricate an FZP with a high focusing efficiency, it is necessary to investigate the relation between the experimental values of the focusing efficiency and the theoretical ones. We have fabricated Ag/C and Cu/Al multilayer (sputtered-sliced) FZPs for use in hard X-ray region, and have compared the measured focusing efficiency data with the calculated ones. The experimental data have been in good agreement with the theoretical values.

In order to attain high diffraction efficiency in high-energy X-ray region, we have developed multilevel-type (6-step) multilayer FZPs with the diameter of 70 μm, which composed of concentric multilayers of alternating high-Z (Cu), low-Z (Al), and four types of composite materials (Cu, Al) layers. Such a multilevel-type FZP with high diffraction efficiency contributes the reduction of the radiation damage to biological specimens, the simplification of the X-ray optical system. Some FZPs are fabricated and their diffraction efficiencies were evaluated at the beamline of SPring-8. For one FZP, the peak efficiency for the 1st-order diffraction of 51% has been obtained at 70 keV. The efficiencies higher than 40% have been achieved in the wide energy range of 70–90 keV. That for the 2nd-order diffraction of 46% has been obtained at 37.5 keV. For another FZP, the peak efficiency for the 1st-order diffraction of 52% has been obtained at 41.3 keV. The efficiencies higher than 45% have been achieved in the wide energy range of 33–49.5 keV.

We investigated a kinoform-style Fresnel zone plate (FZP) that is a high-efficient optical element for hard X-ray focusing. The Cu/Al kinoform-style FZPs were fabricated with a sputtered–sliced method. The FZP was composed of 450 layers (30 layers, 15 pairs) of Al, Cu/Al composite, and Cu. The microstructure of the Cu/Al composite layer was observed by scanning ion microscopy based on a focused ion beam (FIB). In the Cu/Al composite layer, the SIM images obtained by grain orientation contrast observation indicated that the Cu grains were grown gradually with increasing Cu concentration.

We report on the optical humidity sensitivity of nickel oxide (NiO) films prepared by plasma oxidation of nickel–carbon composite films. The plasma-oxidized NiO films showed humidity-sensitive absorbance change at room temperature. The optical absorbance change was strongest at wavelengths around 560 nm. The reversible absorbance change over a wide humidity range of 0–90% RH and the response time within several minutes were obtained with the plasma-oxidized NiO films which is a potential candidate for optical humidity detection.

The tin oxide (SnO2) films are thermally and chemically stable, and have been applied to various fields. The SnO2 (non-doped) films were prepared by a photochemical vapour deposition (photo-CVD) process. TMT (Sn (CH3) 4) and O2 (containing 4 mol.% O3) were used as the source materials, and a low-pressure mercury lamp was used as the light source. By the combination of a linearly focused low-pressure mercury lamp through a semi-cylindrical suprasil window and a reciprocation of the substrate, a good uniformity along the 8 cm ×10 cm area was realised at a substrate temperature of 200 and 250°C. The SnOO2 films prepared at lower temperature had better uniformity. The minimum resistivity of 6.8 × 10-3Ω·cm was obtained at a substrate temperature of 250°C.

A hard X-ray microbeam with zone-plate optics has been tested at the MR-BW-TL beamline on the Tristan main ring of the KEK, and preliminary experiments on scanning microscopy have also been performed. A sputtered-sliced Fresnel zone plate with an Au core and Ag/C multilayer is used as an X-ray focusing device. The outermost zone width of the zone plate is 0.25 microm. A focused spot size of approximately 0.5 mum has been achieved at an X-ray energy of 8.54 keV. In a scanning X-ray microscopy experiment, test patterns with submicrometer fine structure have been clearly resolved.

A hard x-ray imaging microscope system of high spatial resolution and large field of view (FOV) has been developed at the beamline 37 XU of SPring-8. By utilizing the 30 m-long experimental station, large magnification can be attained with a large diameter Fresnel zone plate (FZP) objective. Some configurations of microscope systems were tested. In a typical condition, a magnification of 133 and a FOV of 123 μm are attained using a FZP with a diameter of 310 μm and an outermost zone width of 100 nm, and the spatial resolution evaluated by observing resolution test chart is 160 nm in full pitch of periodic object with an exposure time of 1 s. When a FZP with an outermost zone width of 50 nm is used, a spatial resolution better than 100 nm is achieved. Phase-contrast imaging by Zernike’s method was also tested, and three dimensional measurement by computer tomography (CT) method was also carried out.

Electrochromic (EC) nickel oxide (NiO) films were prepared either by plasma oxidation of vacuum-deposited nickel-carbon (Ni–C) composite films or by thermal oxidation of those films. EC properties of the NiO films were measured by cyclic voltammetry in 1 M KOH. The degree of electrochromism in the NiO films depended not only on the Ni-to-C (Ni/C) ratio in the Ni–C films but also on the oxidation conditions of the Ni–C films. The NiO film with a Ni/C ratio of ∼0.6 showed the longest cycling ability among the films with three different Ni/C ratios (∼0.3, ∼0.6 and ∼1.2). The NiO film thermally oxidized at 500° C showed smaller transmission modulation and passed charge density than the plasma oxidized film, but could be electrochemically switched for more than 5000 cycles without serious residual coloration.

Although high-quality SnO 2 films have been prepared above 400°C, we prepared highly-conductive transparent F-doped SnO 2 films below about 350°C and at high growth rates, using a new raw material system of Sn(CH 3 ) 4 , O 2 containing 5 mol.% O 3 , and HF-acid. At a substrate temperature of 350°C, the films, which had properties such as sheet resistances of 1.6 and 4.5 Ω /□, resistivities of 3.4 and 4.5 × 10 −4 Ω cm, and transmittances including substrates of 70% and 80% at 550 nm, were prepared by thermal-CVD and photo-CVD (chemical vapour deposition), respectively. Several optical and electrical properties of the films prepared by both CVD methods were compared.

We report on a novel dry process for preparing NiO films by plasma oxidation of NiC composite films, which have been deposited by co-evaporation of Ni and C from two different sources. After being hydrated in KOH electrolyte, the NiO films show fast response and good cycling ability.

A synchrotron radiation hard X-ray microbeam (SR) will be a new powerful tool for SR photo-excited material fabrication processes. A multilayer zone plate (ZP) fabricated by a sputtered-sliced technique is expected to be a hopeful optical element to form a hard X-ray microbeam. Four types of concentric multilayers (W /C, Cr/C, Ag/C and Cu/C) were fabricated in order to find usable materials for the multilayer ZP, because the roughness of the multilayer interface reduces the focusing performance of the ZP. The Ag/C multilayer was the most suitable ZP material because of less interface roughness and a smooth surface configuration.

Composite materials are widely utilized in a number of fields, such as materials science, metallurgy, polymer science, interface science, mechanical engineering and aerospace engineering. In this chapter, as an application of a composite material layer (thin film) produced by co-sputtering to the hard X-ray focusing optical technique, a multilayer Fresnel zone plate (ML-FZP) with high diffraction efficiency is described. X-rays in the energy region of 100 – 2,000 eV (2 keV) are called soft X-rays (Snigirev & Snigireva, 2008), while those with higher energy are called hard X-rays. Soft X-rays, especially in the “water window” region (Spiller, 1994), are mainly used in the field of biotechnology. On the other hand, hard X-rays are used in various research fields, including materials science, environmental science and medical science. High brilliant hard X-ray beams with submicronor nanometre-scale spot sizes generated by third-generation synchrotron radiation (SR) facilities such as the APS (USA), ESRF (France) or SPring-8 (Japan), especially for use in the high-energy region, have great potential for use in various fields of research. They are remarkably powerful tools. Recently, higher energy (shorter wavelength) X-ray beams above 20 keV have been utilised in a number of applications, including residual stress measurement in metal matrix composites at 40 keV (Korsunsky & Wells, 2000), local strain measurement within bulk materials at 52 and 90 keV (Lienert et al., 2000), a novel experimental scheme for high-resolution X-ray analysis of deeply buried interfaces at 71.3 keV (Reichert et al., 2003), study of the ice–SiO2 model interface, using X-ray transmission–reflection scheme at 71.3 keV (Engemann et al., 2004), mapping of Sr in (Ba,Sr)TiO3 dielectric ceramics using Ka fluorescence X-rays at 25 keV (Takeuchi et al., 2005), micro-XRF (X-ray fluorescence) analysis of heavy metals in the cells of hyperaccumulator plants at 37 and 75 keV (Terada et al., 2004; Terada et al., 2005), non-destructive imaging of integrated circuits (ICs) at 25 keV, and imaging of Au mesh by three types of X-ray microscopy at 82 keV (Awaji et al., 2003; Suzuki et al., 2006). In addition, microscopic imaging of Au mesh at 200 keV has also been reported (Kamijo et al., 2009). Many types of focusing optics have been developed for hard X-rays and their focusing abilities have been improved over the past two decades. Especially within the last several years, there have been dramatic changes in the performances of focusing optics. The main types of focusing optics and their performances are shown in Fig. 1.

A focused MeV nickel ion beam was used for making contact vias in a multilayer structure through a passivation layer. The structures had two aluminum layers isolated by a Si3N4 insulating layer. The distribution of implanted nickel ions was controlled by changing the implantation energy. After the implantation, current-voltage characteristics between the two aluminum layers were measured by a two-point probe method. When the distribution of nickel was adjusted at the Si3N1 insulating layer, electrical conduction was observed at the nickel fluence of 1 × 1017–2 × 1018 ions/cm2, and it was found that the conductivity was increased and the breakdown voltage was decreased as the fluence of nickel ions increased.

The tin oxide (SnO 2 ) films were prepared by a photo-CVD process and characterized by X-ray diffraction (XRD) and electrochemical measurements. The SnO 2 films prepared at 473 and 523 K showed amorphous-like hallow pattern, while the SnO 2 film prepared at 573 K showed a poor crystalline pattern. All the Li/SnO 2 cells showed the reversible capacity of 600 mAh/g in the voltage range of 0.1–0.8 V over 200 cycles. It was clarified that the SnO 2 film showing superior electrochemical performance was prepared at low temperature of 473 K using TMT (Sn(CH 3 ) 4 ) and O 2 (containing 4 mol.% O 3 ) as the source material.

A hard X-ray microbeam created from a sputtered-sliced Fresnel zone plate has been tested at SPring-8 undulator beamline. Focusing properties are evaluated in the X-ray wavelength regions of 0.15– 1.5 A . The measured focal beam size is about 0.6 μm at an X-ray wavelength of 1.4 A . In a scanning microscopy experiment, resolution-test-patterns with 0.2 μm structure are resolved at an X-ray wavelength of 0.45 A .

Tin oxide (non-doped) films have been prepared by a photochemical vapour deposition (photo-CVD) from Tetramethyltin (TMT) (Sn(CH3)4) and O2 (containing O3). A low-pressure mercury lamp was used as the light source. The effect of the UV light irradiation on the film thickness distribution along 5 cm×5 cm area was examined. By piling Teflon films on the surface of the suprasil window, the light intensity of 184.9 nm UV wavelength of the low-pressure mercury lamp was controlled, while that of 253.7 nm wavelength through the Teflon hardly changed. As a result, the uniformity of the film thickness distribution was improved as the light intensity (184.9 nm) increased. The UV 184.9 nm light irradiation may have improved the uniformity of the reactive species distribution in the vapour phase, which may result in the formation of the uniform thickness distribution.

Lead titanate (PbTiO3) thin films were prepared by rf magnetron sputtering using ceramic target. Perovskite phase PbTiO3 was obtained on platinum-coated glass substrate at substrate temperature of 580°C. On the contrary, crystal structure of the films on glass substrate was amorphous. After this film was annealed at 500°C in air, crystal structure was converted to perovskite one. In proportion to the rf power, deposition rate increased. When rf power and substrate temperature were 300 W and 580°C, deposition rates of the films deposited on glass substrate and platinum-coated glass were 50 and 20 nm/min, respectively.

Photochemical vapour deposition (photo-CVD) is expected to be a damage-free process at low temperature. Transparent conductive tin oxide (non-doped) films have been prepared by the photo-CVD process under various deposition conditions. TMT (Sn (CH3)4) and O2 (containing 4 mol.% O3) were used as the raw materials and a low-pressure mercury lamp was used as the light source. By the combination of linearly focused low-pressure mercury lamp light through a semi-cylindrical suprasil window and a reciprocation motion of the substrate, a good uniformity of the film thickness along an 8 × 10 cm area was realised. The growth rate was proportional to both the substrate temperature and the TMT flow rate. The minimum resistivity of ~ 7 × 10−3 Ω cm was obtained at a substrate temperature of 250 °C.

A Fresnel phase zone plate for hard x ray was fabricated by physical vapor deposition alternating transparent and opaque layers onto a fine gold wire core 47 μm in diameter. The zone plate, which is comprised of 25 pairs of alternating Ag and C layers, is designed to operate with a focal length of 124 mm for a parallel beam at 8.1 keV. The thickness of the zone plate is less than 10 μm and is capable of operating as a phase zone plate. Using the brilliant monochromatized x-ray beam from the TRISTAN Main Ring, with an undulator, the minimum focal spot size attained for the first order focal beam was 0.5 μmφ. The light collecting efficiency was determined to be near 11%.