SPring-8 — 大型放射光施設

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

参考文献:
Y. Inubushi et. al., Appl. Sci. 10, 2224 (2020).

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).