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Design and performance of a soft X-ray double crystal monochromator at HSRC
Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 723–726
Design and performance of a soft X-ray double crystal monochromator at HSRC S. Yagia,*, G. Kutluka, T. Matsuia, A. Matanob, A. Hirayab, E. Hashimotoa, M. Taniguchia,b a
Hiroshima Synchrotron Radiation Center, Hiroshima University, Kagamiyama 2-313, Higashi-Hiroshima 739-8526, Japan b Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, Japan
Abstract A new soft X-ray beamline has been constructed at the Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University. This beamline has a unique mechanism of an exchange system for a monochromator crystal. A double crystal monochromator of a Golovchenko-type is equipped with a crystal bank. The beamline delivers photons with energies from 800 to 5000 eV. Users can obtain the effective X-ray absorption fine structure spectra for Si, P, S, Cl, Ar and K K-edge on this beamline. # 2001 Elsevier Science B.V. All rights reserved. Keywords: HiSOR; DCM; XAFS; Inch-worm
1. Introduction The HSRC was established in 1996 as a common facility for both research and education in the field of synchrotron science [1]. The storage ring is named HiSOR (Hiroshima Synchrotron Orbital Radiation) and operated at 700 MeV with 200 mA at present [2]. A heat load power of the HiSOR is smaller than that of the high energy storage ring, for example KEK-PF (2.5 GeV). The HiSOR is of a racetrack type with 16 ports for the beamlines, which include a linear undulator and a
*Corresponding author. Present address: Department of Crystalline Materials Engineering, Faculty of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. Tel.: +81-52-789-3789; fax: +81-52-789-5155. E-mail address: [email protected] (S. Yagi).
helical undulator beamline. Two double crystal monochromator (DCM) beamlines (BL-3 and 11) have been installed at the bending magnet port. In this paper, we describe the design and the performance of BL-3 and 11.
2. Design of the DCM beamline The BL-3 and 11 are soft X-ray beamlines for XAFS (X-ray Absorption Fine Structure) measurements in HSRC. Fig. 1 shows a schematic side view of the beamline. These beamlines are equipped with a diaphragm (with Be window), a double wire monitor for beam position measurement, a focusing pre-mirror (FM) and a double crystal monochromator (DCM). A white synchrotron beam is reflected by bent-cylindrical focusing pre-mirror. The grazing incidence angles of the
0168-9002/01/$ - see front matter # 2001 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 9 0 0 2 ( 0 1 ) 0 0 4 7 8 - 8
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S. Yagi et al. / Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 723–726
Fig. 1. Optical layout of the DCM beamline.
Fig. 3. Transmission curve with use of the InSb (1 1 1) crystals on BL-3. Fig. 2. Inside of the DCM chamber.
two beamlines are 1.28 and 28, respectively. These beamlines are designed to deliver photons with energies from 800 to 5000 eV by using monochromator crystals as Beryl (1 0 1 0), InSb (1 1 1) and Si (1 1 1). The DCM used in these beamlines are a Golovchenko-type [3,4]. Two inch-worms, which are made by Burleigh Instruments, Inc., are equipped to the first crystal holder for adjustment in pitch and roll rotations, respectively. These inch-worms can be baked at 1208C in an UHV condition. The base pressure of the DCM chamber is less than 2 10 9 Torr before leading the synchrotron radiation. The scanning angle of the monochromator is from 708 to 208. The DCM chamber is equipped with a crystal bank system which has six banks and can store three kinds of monochromator crystals, as shown in Fig. 2. The monochromator crystal can be easily moved with a
magnetic transfer rod, which is equipped at the top of the DCM chamber, when a user wants to change an energy region. Therefore, the monochromator crystal can be exchanged without breaking the vacuum and these beamlines can cover a wide energy region. The focused beam size is about 2 2 mm2 (H V) at the sample position.
3. Performance of the DCM beamlines The transmission curve of the BL-3, obtained with the InSb (1 1 1) crystals, is shown in Fig. 3. The cathode current of a photo diode detector (IRD [International Radiation Detectors Inc.] AXUV-100) was 180 nA, the photon flux was estimated to be 4.5 109 photons s 1 with 100 mA using a quantum efficiency of 950 at 2500 eV. Fig. 4 shows a Si K-edge XAFS spectrum of the Si (0 0 1) wafer on BL-3. A splitting of the first peak (1s3p) [5], which is marked a, can be clearly
S. Yagi et al. / Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 723–726
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Fig. 4. Si K-edge XAFS spectrum of a Si (0 0 1) wafer on BL-3. The inset shows the detailed NEXAFS spectrum.
Fig. 5. An Ar K-edge NEXAFS spectrum and a result of a curve fitting on BL-11.
observed in the inset NEXAFS spectrum. Since the splitting separation is smaller than 0.9 eV, it seems that the energy resolution power (E=DE) is more than 2000 [6–8]. We have measured an Ar K-edge NEXAFS spectrum using a Si (1 1 1) crystals and a gas chamber [9] on BL-11. The spectrum is shown in Fig. 5. The Ar pressure was 0.5 Torr in a gas cell,
the length of which was 615 mm. The NEXAFS signal was obtained with the photo diode detector. Since the cathode current was 200 nA, the photon flux was estimated to be 5 109 photons s 1 with 100 mA using a quantum efficiency of 1000 at 3200 eV. It is found that the XAFS spectra for Si, P, S, Cl, Ar and K K-edge can be measured at these beamline stations. The energy resolution
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S. Yagi et al. / Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 723–726
of the BL-11 system was checked by a curve fitting of the Ar K-edge NEXAFS spectrum. Fig. 5 also shows a result of the curve fitting by a Voigt function. The natural width of the first resonance (1s4p) was 0.46 eV [10]. The measured FWHM of the 1s4p resonance was 1.34 eV. Therefore, the resolution power (E=DE) is estimated to be 2400 at around 3200 eV. These results satisfy the design specifications. Acknowledgements The authors would like to thank Dr. S. Shibuya and Dr. S. Masui (Sumitomo Heavy Industry Co. Ltd., Japan) for their valuable suggestions. The authors are grateful for financial support for a part of this work by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, Japan (No. 12650684), a Grant-inAid on Research for the Future ‘‘Photoscience’’ (JSPS-RFTF-98P-01202) from Japan Society for the Promotion of Science (JSPS) and an Electric Technology Research Foundation of Chugoku.
References [1] M. Taniguchi, J. Ghijsen, J. Synchrotron Radiat. 5 (1998) 1176. [2] K. Yoshida, T. Takayama, T. Hori, J. Synchrotron Radiat. 5 (1998) 345. [3] J.A. Golovchenko, R.A. Levesque, P.L. Cowan, Rev. Sci. Instrum. 52 (1981) 509. [4] T. Murata, T. Matsukawa, M. Mori, M. Obashi, S. Nao"e, H. Terauchi, Y. Nishihata, O. Matsudo, J.I. Yamazaki, J. Phys. C8 (Suppl. 12) (1986) 135. [5] N. Nagashima, A. Nakano, K. Ogata, M. Tamura, K. Sugawara, K. Hayamawa, Phys. Rev. B 48 (1993) 18257. [6] B.X. Yang, F.H. Middleton, B.G. Olsson, G.M. Bancroft, J.M. Chen, T.K. Sham, K. Tan, D.J. Wallace, Nucl. Instr. and Meth. A 316 (1992) 422. [7] Y. Kitajima, Rev. Sci. Instrum. 66 (1995) 1413. [8] T.E. Dann, S.C. Chun, L.J. Huang, J.M. Juang, C.L. Chen, K.L. Tsang, J. Synchrotron Radiat. 5 (1998) 664. [9] The gas chamber was designed by T. Matsui, G. Kutluk, H. Yoshida. The design and details are reported in T. Matsui, K. Gekko, N. Ojima, K. Sakai, K. Matsuo, S. Nakamura, HSRC Activity Report 1998–1999. [10] V. Gotte, A. Rogalev, C. Goulon-Ginet, J. Goulon, C. Comte, R. Guilard, P. Cocolios, ESRF Activity Report, 1997.
Design and performance of a soft X-ray double crystal monochromator at HSRC S. Yagia,*, G. Kutluka, T. Matsuia, A. Matanob, A. Hirayab, E. Hashimotoa, M. Taniguchia,b a
Hiroshima Synchrotron Radiation Center, Hiroshima University, Kagamiyama 2-313, Higashi-Hiroshima 739-8526, Japan b Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, Japan
Abstract A new soft X-ray beamline has been constructed at the Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University. This beamline has a unique mechanism of an exchange system for a monochromator crystal. A double crystal monochromator of a Golovchenko-type is equipped with a crystal bank. The beamline delivers photons with energies from 800 to 5000 eV. Users can obtain the effective X-ray absorption fine structure spectra for Si, P, S, Cl, Ar and K K-edge on this beamline. # 2001 Elsevier Science B.V. All rights reserved. Keywords: HiSOR; DCM; XAFS; Inch-worm
1. Introduction The HSRC was established in 1996 as a common facility for both research and education in the field of synchrotron science [1]. The storage ring is named HiSOR (Hiroshima Synchrotron Orbital Radiation) and operated at 700 MeV with 200 mA at present [2]. A heat load power of the HiSOR is smaller than that of the high energy storage ring, for example KEK-PF (2.5 GeV). The HiSOR is of a racetrack type with 16 ports for the beamlines, which include a linear undulator and a
*Corresponding author. Present address: Department of Crystalline Materials Engineering, Faculty of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. Tel.: +81-52-789-3789; fax: +81-52-789-5155. E-mail address: [email protected] (S. Yagi).
helical undulator beamline. Two double crystal monochromator (DCM) beamlines (BL-3 and 11) have been installed at the bending magnet port. In this paper, we describe the design and the performance of BL-3 and 11.
2. Design of the DCM beamline The BL-3 and 11 are soft X-ray beamlines for XAFS (X-ray Absorption Fine Structure) measurements in HSRC. Fig. 1 shows a schematic side view of the beamline. These beamlines are equipped with a diaphragm (with Be window), a double wire monitor for beam position measurement, a focusing pre-mirror (FM) and a double crystal monochromator (DCM). A white synchrotron beam is reflected by bent-cylindrical focusing pre-mirror. The grazing incidence angles of the
0168-9002/01/$ - see front matter # 2001 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 9 0 0 2 ( 0 1 ) 0 0 4 7 8 - 8
724
S. Yagi et al. / Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 723–726
Fig. 1. Optical layout of the DCM beamline.
Fig. 3. Transmission curve with use of the InSb (1 1 1) crystals on BL-3. Fig. 2. Inside of the DCM chamber.
two beamlines are 1.28 and 28, respectively. These beamlines are designed to deliver photons with energies from 800 to 5000 eV by using monochromator crystals as Beryl (1 0 1 0), InSb (1 1 1) and Si (1 1 1). The DCM used in these beamlines are a Golovchenko-type [3,4]. Two inch-worms, which are made by Burleigh Instruments, Inc., are equipped to the first crystal holder for adjustment in pitch and roll rotations, respectively. These inch-worms can be baked at 1208C in an UHV condition. The base pressure of the DCM chamber is less than 2 10 9 Torr before leading the synchrotron radiation. The scanning angle of the monochromator is from 708 to 208. The DCM chamber is equipped with a crystal bank system which has six banks and can store three kinds of monochromator crystals, as shown in Fig. 2. The monochromator crystal can be easily moved with a
magnetic transfer rod, which is equipped at the top of the DCM chamber, when a user wants to change an energy region. Therefore, the monochromator crystal can be exchanged without breaking the vacuum and these beamlines can cover a wide energy region. The focused beam size is about 2 2 mm2 (H V) at the sample position.
3. Performance of the DCM beamlines The transmission curve of the BL-3, obtained with the InSb (1 1 1) crystals, is shown in Fig. 3. The cathode current of a photo diode detector (IRD [International Radiation Detectors Inc.] AXUV-100) was 180 nA, the photon flux was estimated to be 4.5 109 photons s 1 with 100 mA using a quantum efficiency of 950 at 2500 eV. Fig. 4 shows a Si K-edge XAFS spectrum of the Si (0 0 1) wafer on BL-3. A splitting of the first peak (1s3p) [5], which is marked a, can be clearly
S. Yagi et al. / Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 723–726
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Fig. 4. Si K-edge XAFS spectrum of a Si (0 0 1) wafer on BL-3. The inset shows the detailed NEXAFS spectrum.
Fig. 5. An Ar K-edge NEXAFS spectrum and a result of a curve fitting on BL-11.
observed in the inset NEXAFS spectrum. Since the splitting separation is smaller than 0.9 eV, it seems that the energy resolution power (E=DE) is more than 2000 [6–8]. We have measured an Ar K-edge NEXAFS spectrum using a Si (1 1 1) crystals and a gas chamber [9] on BL-11. The spectrum is shown in Fig. 5. The Ar pressure was 0.5 Torr in a gas cell,
the length of which was 615 mm. The NEXAFS signal was obtained with the photo diode detector. Since the cathode current was 200 nA, the photon flux was estimated to be 5 109 photons s 1 with 100 mA using a quantum efficiency of 1000 at 3200 eV. It is found that the XAFS spectra for Si, P, S, Cl, Ar and K K-edge can be measured at these beamline stations. The energy resolution
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S. Yagi et al. / Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 723–726
of the BL-11 system was checked by a curve fitting of the Ar K-edge NEXAFS spectrum. Fig. 5 also shows a result of the curve fitting by a Voigt function. The natural width of the first resonance (1s4p) was 0.46 eV [10]. The measured FWHM of the 1s4p resonance was 1.34 eV. Therefore, the resolution power (E=DE) is estimated to be 2400 at around 3200 eV. These results satisfy the design specifications. Acknowledgements The authors would like to thank Dr. S. Shibuya and Dr. S. Masui (Sumitomo Heavy Industry Co. Ltd., Japan) for their valuable suggestions. The authors are grateful for financial support for a part of this work by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, Japan (No. 12650684), a Grant-inAid on Research for the Future ‘‘Photoscience’’ (JSPS-RFTF-98P-01202) from Japan Society for the Promotion of Science (JSPS) and an Electric Technology Research Foundation of Chugoku.
References [1] M. Taniguchi, J. Ghijsen, J. Synchrotron Radiat. 5 (1998) 1176. [2] K. Yoshida, T. Takayama, T. Hori, J. Synchrotron Radiat. 5 (1998) 345. [3] J.A. Golovchenko, R.A. Levesque, P.L. Cowan, Rev. Sci. Instrum. 52 (1981) 509. [4] T. Murata, T. Matsukawa, M. Mori, M. Obashi, S. Nao"e, H. Terauchi, Y. Nishihata, O. Matsudo, J.I. Yamazaki, J. Phys. C8 (Suppl. 12) (1986) 135. [5] N. Nagashima, A. Nakano, K. Ogata, M. Tamura, K. Sugawara, K. Hayamawa, Phys. Rev. B 48 (1993) 18257. [6] B.X. Yang, F.H. Middleton, B.G. Olsson, G.M. Bancroft, J.M. Chen, T.K. Sham, K. Tan, D.J. Wallace, Nucl. Instr. and Meth. A 316 (1992) 422. [7] Y. Kitajima, Rev. Sci. Instrum. 66 (1995) 1413. [8] T.E. Dann, S.C. Chun, L.J. Huang, J.M. Juang, C.L. Chen, K.L. Tsang, J. Synchrotron Radiat. 5 (1998) 664. [9] The gas chamber was designed by T. Matsui, G. Kutluk, H. Yoshida. The design and details are reported in T. Matsui, K. Gekko, N. Ojima, K. Sakai, K. Matsuo, S. Nakamura, HSRC Activity Report 1998–1999. [10] V. Gotte, A. Rogalev, C. Goulon-Ginet, J. Goulon, C. Comte, R. Guilard, P. Cocolios, ESRF Activity Report, 1997.