X線集光特性
超高ピーク輝度をもつXFELパルスは、集光することでその性能を更に高めることができます。SACLAでは、主にKBミラー（Kirkpatrick-Baez mirror）や複合屈折レンズ（CRLs: Compound refractive lenses）による集光XFELを利用することができます。本ページでは、SACLAにおけるX線集光特性について紹介します。
BL1におけるX線集光システム
| Experimental Hutch |
Focusing System | Typical Spot Size |
| EH4a | KBミラー | ~5 µm FWHM |
| EH4a | KB+回転楕円体ミラー （基盤開発プログラムで開発中） |
~500 nm FWHM |
EH4a@BL1 汎用集光システムの詳細
EH4aの常設KBミラー集光システムは、軟X線XFELを利用した実験に汎用的に利用されます。また、このKBミラーと回転楕円体ミラーを組み合わせた500 nm集光システムの開発が、SACLA基盤開発プログラムを通じて行われています。
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Carbon | Carbon |
| Substrate size | 600 × 50 × 50 mm | 600 × 50 × 50 mm |
| Glancing angle | 1.5 deg | 1.5 deg |
| Focal length | 2.00 m | 2.65 m |
| Distance from source | 85 m | 85 m |
| Spatial acceptance | 15.1 mm | 15.1 mm |
| Typical focal size @100eV | ~5 µm FWHM | ~5 µm FWHM |
参考文献:
S. Owada et al., J. Synchrotron Rad., 25, 282 (2018).
BL2におけるX線集光システム
| Experimental Hutch |
Focusing System | Typical Spot Size |
| EH3 | KBミラー | ~1 µm FWHM |
| EH4b | 多層膜KBミラー（MAXIC-S） | ~100 nm FWHM |
| EH6 | CRLs | > 3 µm FWHM |
EH3@BL2 汎用集光システムの詳細
EH3のKBミラー集光システムは、SFXやCDIを始め、様々な実験に汎用的に利用されます。光子エネルギーによって、斜入射角2 mrad系および4 mrad系の2種類のKBミラーを使い分けることが可能です。
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Rhodium | Rhodium |
| Substrate size | 600 × 50 × 50 mm | 600 × 50 × 50 mm |
| Glancing angle (2 mrad/4 mrad)* | 2.1/3.8 mrad | 2.0/3.7 mrad |
| Focal length | 1.95 m | 1.30 m |
| Distance from source | 140.00 m | 140.65 m |
| Spatial acceptance (2 mrad/4 mrad)* | >1.2/>2.2 mm | >1.1/>2.1 mm |
| Divergent angle (2 mrad/4 mrad)* | ~0.65/~1.2 mrad | ~1.0/~1.7 mrad |
| Typical focal size @ 10 keV | ~1 µm FWHM | ~1 µm FWHM |
*高エネルギー領域では2 mrad系、低エネルギー領域では4 mrad系を利用する。
EH4b@BL2 MAXIC-S用集光システムの詳細
EH4bに常設されているCDI実験の共用装置である MAXIC-S用の多層膜KBミラー集光システムです。光子エネルギー4 keVのXFELを約55%の効率で集光可能で、高強度X線ビームを用いた実験に利用されます。
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Cr/C 30 layers | Cr/C 30 layers |
| Substrate size | 80 × 50 × 30 mm | 80 × 50 × 30 mm |
| Glancing angle | 25 mrad | 25 mrad |
| Focal length | 100 mm | 190 mm |
| Spatial acceptance | ~2 mm | ~2 mm |
| Divergent angle | ~22 mrad | ~11 mrad |
| Typical focal size @4 keV | ~70 nm FWHM | ~120 nm FWHM |
参考文献:
T. Koyama et al., Microsc. Microanal. 24 (S2), 294 (2018).
EH6@BL2 500TWレーザー利用実験用集光システムの詳細
EH6の500TWレーザー利用実験用のCRLs集光システムです。試料位置を固定したまま、所望するビーム径のXFELを利用して実験を行うことが可能です。
| Optical parameters (CRLs) | |
| Material | Beryllium |
| Shape of lenses | Paraboloid |
| Radii of curvatures (R) | 500, 1000, 1500, 2000 µm |
| Maximum number of lenses | 63 with R = 500 µm 3 with R = 1000 µm 3 with R = 1500 µm 3 with R = 2000 µm |
| Focal length | 3 m |
| Spatial acceptance | > 1.3 mm |
| Divergent angle | > 0.2 mrad* |
| Typical focal size @10 keV | ~3 µm FWHM* |
*使用するレンズの数や波長に依存します。
参考文献：
T. Yabuuchi et al., J. Synchrotron Rad. 26, 585 (2019).
BL3におけるX線集光システム
| Experimental Hutch |
Focusing System | Typical Spot Size |
| EH2 | CRLs | > 1 µm FWHM |
| EH4c | KBミラー | ~1 µm FWHM |
| EH5 | ナノ集光用KBミラー | 100-200 nm FWHM |
| EH5 | 100Jレーザー実験用KBミラー | ~500 nm FWHM |
EH2@BL3 汎用集光システムの詳細
EH2のCRLs集光システムは、SFXやX線回折、X線分光を始めとした各種実験に汎用的に利用されます。
| Optical parameters (CRLs) | |
| Material | Beryllium |
| Shape of lenses | Paraboloid |
| Radii of curvatures (R) | 200, 500 µm |
| Maximum number of lenses | 31 with R = 200 µm 15 with R = 500 µm |
| Focal length | 2.5 m |
| Spatial acceptance | > 0.9 mm |
| Divergent angle | > 0.1 mrad* |
| Typical focal size @10 keV | 1-2 µm FWHM* |
*使用するレンズの数や波長に依存します。
参考文献:
T. Katayama et al., J. Synchrotron Rad. 26, 333 (2019).
EH4c@BL3 汎用集光システムの詳細
EH4cのKBミラー集光システムは、X線回折を始め、様々な実験に汎用的に利用されます。光子エネルギーによって、斜入射角2 mrad系および4 mrad系の2種類のKBミラーを使い分けることが可能です。
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Rhodium | Rhodium |
| Substrate size | 600 × 50 × 50 mm | 600 × 50 × 50 mm |
| Glancing angle (2 mrad/4 mrad)* | 2.1/3.8 mrad | 2.0/3.7 mrad |
| Focal length | 1.95 m | 1.30 m |
| Distance from source | 140.00 m | 140.65 m |
| Spatial acceptance (2 mrad/4 mrad)* | > 1.2/> 2.2 mm | > 1.1/> 2.1 mm |
| Divergent angle (2 mrad/4 mrad)* | ~0.65/1.2 mrad | ~1.0/~1.7 mrad |
| Typical focal size @10 keV | ~1 µm FWHM | ~1 µm FWHM |
*高エネルギー領域では2 mrad系、低エネルギー領域では4 mrad系を利用する。
EH5@BL3 ナノ集光システムの詳細
EH5のKBミラーナノ集光システムは、ピーク強度が1020 W/cm2に到達するような超高強度X線ナノビームを活用する実験に利用されます。光子エネルギー12 keV以下の領域で、色収差なく高効率にXFELを集光することが可能です。
| Optical parameters (KB Mirrors) | Vertical | Horizontal |
| Surface coating | Rhodium | Rhodium |
| Substrate size | 250 × 50 × 50 mm | 250 × 50 × 50 mm |
| Glancing angle | 4.0 mrad | 3.8 mrad |
| Focal length | 500 mm | 240 mm |
| Distance from source | 220 m | 220.26 m |
| Effective mirror length |
242 mm | 242 mm |
| Spatial acceptance | 970 μm | 920 μm |
| Divergent angle | ~2 mrad | ~4.5 mrad |
| Typical focal size @10keV | ~200 nm FWHM | ~120 nm FWHM |
参考文献:
H. Yumoto et al., Appl. Sci. 10, 2611 (2020).
EH5@BL3 100Jレーザー利用実験用集光システムの詳細
EH5の100Jレーザー利用実験用のKBミラー集光システムです。典型的な実験で用いられるX線回折測定の分解能を担保するために、回折方向（縦方向）の発散角が1 mrad程度以下となるよう光学設計されています。
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Rhodium | Rhodium |
| Substrate size | 300 × 50 × 50 mm | 400 × 50 × 50 mm |
| Glancing angle | 4.0 mrad | 3.7 mrad |
| Focal length | 1200 mm | 800 mm |
| Distance from source | ~260 m | ~260 m |
| Spatial acceptance | > 1.2 mm | > 1.4 mm |
| Divergent angle | ~1 mrad | ~2 mrad |
| Typical focal size @10keV | ~430 nm FWHM | ~480 nm FWHM |
Special Characteristics of X-Ray Focusing
XFEL pulses with ultra high-peak brightness can further improve the quality of focused light. SACLA typically uses focused XFEL with KB mirrors (Kirkpatrick-Baez mirrors) and CRL (Compound Refractive Lenses). This page will introduce the X-ray focusing characteristics at SACLA.
The X-ray focusing system at BL1
| Experimental Hutch |
Focusing System | Typical Spot Size |
| EH4a | KB mirror | ~5 µm FWHM |
| EH4a | KB + Spheroid Mirror （Under development by the Basic Development Program） |
~500 nm FWHM |
Details of the general-purpose focusing system at EH4a@BL1
The permanent KB mirror focusing system at EH4a is commonly used for experiments using the soft X-ray XFEL. In addition, the development of the 500 nm focusing system that combines the KB mirror and a spheroid mirror is being conducted through the SACLA Basic Development Program.
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Carbon | Carbon |
| Substrate size | 600 × 50 × 50 mm | 600 × 50 × 50 mm |
| Glancing angle | 1.5 deg | 1.5 deg |
| Focal length | 2.00 m | 2.65 m |
| Distance from source | 85 m | 85 m |
| Spatial acceptance | 15.1 mm | 15.1 mm |
| Typical focal size @100eV | ~5 µm FWHM | ~5 µm FWHM |
References:
S. Owada et al., J. Synchrotron Rad., 25, 282 (2018).
X-ray focusing system at BL2
| Experimental Hutch |
Focusing System | Typical Spot Size |
| EH3 | KB mirror | ~1 µm FWHM |
| EH4b | Multilayer Film KB Mirror（MAXIC-S） | ~100 nm FWHM |
| EH6 | CRLs | > 3 µm FWHM |
Details on the general-purpose focusing system at EH3@BL2
The KB mirror focusing system at EH3 is widely used for various experiments including SFX and CDI. Depending on the photon energy, it is possible to use two types of KB mirrors with an oblique angle of incidence of 2 mrad and 4 mrad.
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Rhodium | Rhodium |
| Substrate size | 600 × 50 × 50 mm | 600 × 50 × 50 mm |
| Glancing angle (2 mrad/4 mrad)* | 2.1/3.8 mrad | 2.0/3.7 mrad |
| Focal length | 1.95 m | 1.30 m |
| Distance from source | 140.00 m | 140.65 m |
| Spatial acceptance (2 mrad/4 mrad)* | >1.2/>2.2 mm | >1.1/>2.1 mm |
| Divergent angle (2 mrad/4 mrad)* | ~0.65/~1.2 mrad | ~1.0/~1.7 mrad |
| Typical focal size @ 10 keV | ~1 µm FWHM | ~1 µm FWHM |
*The 2 mrad system is used in the high-energy region, and the 4 mrad system is used in the low-energy region.
Details on the MAXIC-S focusing system at EH4b@BL2
This is a multilayer film KB mirror focusing system used for MAXIC-S permanently installed in EH4b, and is a shared device for CDI experiments . XFEL with a photon energy of 4 keV can be focused with an efficiency of approximately 55%, enabling experiments using high-intensity X-ray beams.
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Cr/C 30 layers | Cr/C 30 layers |
| Substrate size | 80 × 50 × 30 mm | 80 × 50 × 30 mm |
| Glancing angle | 25 mrad | 25 mrad |
| Focal length | 100 mm | 190 mm |
| Spatial acceptance | ~2 mm | ~2 mm |
| Divergent angle | ~22 mrad | ~11 mrad |
| Typical focal size @4 keV | ~70 nm FWHM | ~120 nm FWHM |
References:
T. Koyama et al., Microsc. Microanal. 24 (S2), 294 (2018).
Details on the 500TW laser experimental focusing system at EH6@BL2
The CRL focusing system is used at EH6 for 500TW laser experiments. Experiments can be performed using XFEL with the desired beam diameter while the sample position remains fixed.
| Optical parameters (CRLs) | |
| Material | Beryllium |
| Shape of lenses | Paraboloid |
| Radii of curvatures (R) | 500, 1000, 1500, 2000 µm |
| Maximum number of lenses | 63 with R = 500 µm 3 with R = 1000 µm 3 with R = 1500 µm 3 with R = 2000 µm |
| Focal length | 3 m |
| Spatial acceptance | > 1.3 mm |
| Divergent angle | > 0.2 mrad* |
| Typical focal size @10 keV | ~3 µm FWHM* |
*Depends on the wavelength and number of lenses used.
References:
T. Yabuuchi et al., J. Synchrotron Rad. 26, 585 (2019).
X-ray focusing system at BL3
| Experimental Hutch |
Focusing System | Typical Spot Size |
| EH2 | CRLs | > 1 µm FWHM |
| EH4c | KB mirror | ~1 µm FWHM |
| EH5 | Nano focusing KB mirror | 100-200 nm FWHM |
| EH5 | 100J laser experimental KB mirror | ~500 nm FWHM |
Details on the general-purpose focusing systems at EH2@BL3
The CRL focusing system at EH2 is widely used for various experiments, such as SFX, X-ray diffraction, and X-ray spectroscopy.
| Optical parameters (CRLs) | |
| Material | Beryllium |
| Shape of lenses | Paraboloid |
| Radii of curvatures (R) | 200, 500 µm |
| Maximum number of lenses | 31 with R = 200 µm 15 with R = 500 µm |
| Focal length | 2.5 m |
| Spatial acceptance | > 0.9 mm |
| Divergent angle | > 0.1 mrad* |
| Typical focal size @10 keV | 1-2 µm FWHM* |
*Depends on the wavelength and number of lenses used.
References:
T. Katayama et al., J. Synchrotron Rad. 26, 333 (2019).
Details on the general-purpose focusing systems at EH4c@BL3
The KB mirror focusing system at EH4c is widely used for various experiments including X-ray diffraction. Depending on the photon energy, it is possible to use two types of KB mirrors with an oblique angle of incidence of 2 mrad and 4 mrad.
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Rhodium | Rhodium |
| Substrate size | 600 × 50 × 50 mm | 600 × 50 × 50 mm |
| Glancing angle (2 mrad/4 mrad)* | 2.1/3.8 mrad | 2.0/3.7 mrad |
| Focal length | 1.95 m | 1.30 m |
| Distance from source | 140.00 m | 140.65 m |
| Spatial acceptance (2 mrad/4 mrad)* | > 1.2/> 2.2 mm | > 1.1/> 2.1 mm |
| Divergent angle (2 mrad/4 mrad)* | ~0.65/1.2 mrad | ~1.0/~1.7 mrad |
| Typical focal size @10 keV | ~1 µm FWHM | ~1 µm FWHM |
*The 2 mrad system is used in the high-energy region, and the 4 mrad system is used in the low-energy region.
Details on the nano focusing system at EH5@BL3
The KB mirror nano focusing system at EH5 has peak intensity 1020 W/cm2 and is used in experiments that require ultra high-intensity X-ray nanobeams. It is possible to collect XFEL with high-efficiency without chromatic aberration in the region where the photon energy is 12 keV or less.
| Optical parameters (KB Mirrors) | Vertical | Horizontal |
| Surface coating | Rhodium | Rhodium |
| Substrate size | 250 × 50 × 50 mm | 250 × 50 × 50 mm |
| Glancing angle | 4.0 mrad | 3.8 mrad |
| Focal length | 500 mm | 240 mm |
| Distance from source | 220 m | 220.26 m |
| Effective mirror length |
242 mm | 242 mm |
| Spatial acceptance | 970 μm | 920 μm |
| Divergent angle | ~2 mrad | ~4.5 mrad |
| Typical focal size @10keV | ~200 nm FWHM | ~120 nm FWHM |
References:
H. Yumoto et al., Appl. Sci. 10, 2611 (2020).
Details on the 100J laser experimental focusing system at EH5@BL3
This KB mirror focusing system at EH5 is used for 100J laser experiments. In order to ensure the resolution of the X-ray diffraction measurements during a typical experiment, the optical design is such that the divergence angle in the diffraction direction (vertical) is approximately 1 mrad or less.
| Optical parameters (KB mirrors) | Vertical | Horizontal |
| Surface coating | Rhodium | Rhodium |
| Substrate size | 300 × 50 × 50 mm | 400 × 50 × 50 mm |
| Glancing angle | 4.0 mrad | 3.7 mrad |
| Focal length | 1200 mm | 800 mm |
| Distance from source | ~260 m | ~260 m |
| Spatial acceptance | > 1.2 mm | > 1.4 mm |
| Divergent angle | ~1 mrad | ~2 mrad |
| Typical focal size @10keV | ~430 nm FWHM | ~480 nm FWHM |
References:
Y. Inubushi et. al., Appl. Sci. 10, 2224 (2020).