Abstract

A flat-field extreme ultraviolet (EUV) spectrometer with a nominal 2400grooves/mm aberration-corrected ruled grating has been developed to analyze the emission spectrum in the wavelength range of 10 to 130  Å from large helical device (LHD) plasmas. Spectral properties such as resolution, sensitivity, contribution of higher-order light, and background stray light have been studied using emission spectra mainly from intrinsic impurities, e.g., C and Fe. It is found that the spectrometer well resolves closely existing spectral lines of highly ionized medium- and high-Z impurities even in a very short wavelength range such as 10 to 20  Å. As a result, it allows one to study the charge state distribution of elements in high-temperature fusion plasma. The ruled grating was then replaced by a laminar type holographic grating for the comparative study. The spectral resolution for the ruled grating (Δλ0.08  Å at 33.73  Å) is clearly better than the holographic grating (Δλ0.13  Å at 33.73  Å). Both gratings well suppress the higher-order light, e.g., the second-order light is only less than 11% of the first-order light for C vi (33.73  Å). Relative sensitivity calibration with the wavelength has been done using bremsstrahlung continuum from the LHD plasmas. Absolute intensity calibration has been done by comparing the spectral intensities directly with the absolutely calibrated 1200grooves/mm EUV spectrometer in the overlapping range of 90120  Å due to the absence of a good branching pair in 10130  Å. As a typical result on the present spectrometer well-resolved n=23 full transition arrays from Ne- to Li-like ions are measured for Fe and Ti and wavelengths of the spectral array are tabulated for each charge state. Spectroscopic comparison is also made between the 1200grooves/mm and 2400grooves/mm gratings in a range of 50130  Å.

© 2008 Optical Society of America

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References

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  1. C. De Michelis and M. Mattioli, "Spectroscopy and impurity behavior in fusion plasmas," Rep. Prog. Phys. 47, 1233-1346 (1984).
    [CrossRef]
  2. H. Nozato, S. Morita, M. Goto, A. Ejiri, and Y. Takase, "Acceleration characteristics of spherical and nonspherical pellets by the LHD impurity pellet injector," Rev. Sci. Instrum. 74, 2032-2035 (2003).
    [CrossRef]
  3. R. Katai, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Development of double-structure heavy-elements impurity pellet for active spectroscopy of high-temperature plasmas," Jpn. J. Appl. Phys. , Part 1 46, 3667-3669 (2007).
    [CrossRef]
  4. S. Morita, M. Goto, S. Masuzaki, H. Suzuki, K. Tanaka, H. Nozato, Y. Takeiri, J. Miyazawa, and LHD experimental group, "Effect of Ne glow discharge on ion density control in LHD," Plasma Sci. Tech. 6, 2440-2444 (2004).
    [CrossRef]
  5. S. Morita, M. Goto, Y. Takeiri, J. Miyazawa, S. Murakami, K. Narihara, M. Osakabe, K. Yamazaki, T. Akiyama, N. Ashikawa, M. Emoto, M. Fujiwara, H. Funaba, P. Goncharov, Y. Hamada, K. Ida, H. Idei, T. Ido, K. Ikeda, S. Inagaki, M. Isobe, K. Itoh, O. Kaneko, K. Kawahata, H. Kawazome, K. Khlopenkov, T. Kobuchi, A. Komori, A. Kostrioukov, S. Kubo, R. Kumazawa, Y. Liang, S. Masuzaki, K. Matsuoka, T. Minami, T. Morisaki, O. Motojima, S. Muto, T. Mutoh, Y. Nagayama, Y. Nakamura, H. Nakanishi, Y. Narushima, K. Nishimura, A. Nishizawa, N. Noda, T. Notake, H. Nozato, S. Ohdachi, K. Ohkubo, N. Ohyabu, Y. Oka, T. Ozaki, B. J. Peterson, A. Sagara, T. Saida, K. Saito, S. Sakakibara, R. Sakamoto, M. Sasao, K. Sato, M. Sato, T. Satow, T. Seki, T. Shimozuma, M. Shoji, S. Sudo, H. Suzuki, N. Takeuchi, N. Tamura, K. Tanaka, K. Toi, T. Tokuzawa, Y. Torii, K. Tsumori, T. Uda, K. Y. Watanabe, T. Watari, Y. Xu, H. Yamada, I. Yamada, S. Yamamoto, T. Yamamoto, M. Yokoyama, Y. Yoshimura, and M. Yoshinuma, "Experimental study on ion temperature behaviors in ECH, ICRF and NBI H2, He and Ne discharges of the large helical device," Nucl. Fusion 43, 899-909 (2003).
    [CrossRef]
  6. R. Katai, S. Morita, and M. Goto, "Identification and intensity analysis on forbidden magnetic dipole emission lines of highly charged Al, Ar, Ti and Fe ions in LHD," J. Quant. Spectrosc. Radiat. Transfer 107, 120-140 (2007).
    [CrossRef]
  7. R. Katai, S. Morita, and M. Goto, "Observation of visible and near-UV M1 transitions from highly charged Kr, Mo and Xe ions in LHD and its prospect to impurity spectroscopy for D-T burning plasmas," Plasma Fusion Res. 2, 1-4 (2007).
    [CrossRef]
  8. M. B. Chowdhuri, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Line analysis of EUV spectra from molybdenum and tungsten injected with impurity pellets in LHD," Plasma Fusion Res. 2, S1060 (2007).
    [CrossRef]
  9. M. Koike, T. Yamazaki, and Y. Harada, "Design of holographic gratings recorded with aspheric wave-front recording optics for soft x-ray flat-field spectrographs," J. Electron Spectrosc. Relat. Phenom. 101-103, 913-918 (1999).
    [CrossRef]
  10. N. Nakano, H. Kurada, T. Kita, and T. Harada, "Development of a flat-field grazing-incidence XUV spectrometer and its application in picosecond XUV spectroscopy," Appl. Opt. 23, 2386-2392 (1984).
    [CrossRef] [PubMed]
  11. M. B. Chowdhuri, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Spectroscopic comparison between 1200 grooves/mm ruled and holographic gratings of a flat-field spectrometer and its absolute sensitivity calibration using bremsstrahlung continuum," Rev. Sci. Instrum. 78, 023501 (2007).
    [CrossRef] [PubMed]
  12. M. Koike, K. Sano, E. Gullikson, Y. Harada, and H. Kumata, "Performance of laminar-type holographic grating for a soft x-ray flat-field spectrograph in the 0.7-6 nm region," Rev. Sci. Instrum. 74, 1156-1158 (2003).
    [CrossRef]
  13. W. L. Hodge, B. C. Stratton, and H. W. Moos, "Grazing incidence time-resolved spectrograph for magnetic fusion plasma diagnostics," Rev. Sci , Instrum. 55, 16-24 (1984).
    [CrossRef]
  14. M. May, J. Lepson, P. Beiersdorfer, D. Thorn, H. Chen, D. Hey, and A. Smith, "Photometric calibration of an EUV flat field spectrometer at the advanced light source," Rev. Sci. Instrum. 74, 2011-2013 (2003).
    [CrossRef]
  15. A. M. Daltrini and M. Machida, "Modified branching ratio method for absolute intensity calibration in VUV spectroscopy," IEEE Trans. Plasma Sci. 33, 1961-1967 (2005).
    [CrossRef]
  16. J. H. Parkinson, "New observations of Fe xvii in the solar x-ray spectrum," Astron. Astrophys. 24, 215-218 (1973).
  17. K. J. H. Phillips, R. Mewe, L. K. Harra-Murnion, J. S. Kaastra, P. Beiersdorfer, G. V. Brown, and D. A. Liedahl, "Benchmarking the MEKAL spectral code with solar x-ray spectra," Astron. Astrophys. , Suppl. Ser. 138, 381-393 (1999).
  18. G. V. Brown, P. Beiersdorfer, D. A. Liedahl, K. Widmann, and S. M. Kahn, "Laboratory measurements and modeling of the Fe xvii x-ray spectrum," Astrophys. J. 502, 1015-1026 (1998).
    [CrossRef]
  19. G. V. Brown, P. Beiersdorfer, D. A. Liedahl, K. Widmann, S. M. Kahn, and E. J. Clothiaux, "Laboratory measurements and identification of the Fe xviii-xxivL-shell x-ray line emission," Astrophys. J. , Suppl. Ser. 140, 589-607 (2002).
    [CrossRef]
  20. P. Beiersdorfer, S. von Goeler, M. Bitter, and D. B. Thorn, "Measurements of the 3d --> 2p resonance to intercombination line-intensity ratio in neon-like Fe xvii, Ge xxiii, and Se xxv," Phys. Rev. A 64, 032705 (2001).
    [CrossRef]
  21. K. J. H. Phillips, C. J. Greer, A. K. Bhatia, I. H. Coffey, R. Barnsley, and F. P. Keenan, "Fe xvii x-ray lines in solar coronal and laboratory plasmas," Astron Astrophys. 324, 381-394 (1997).
  22. S. B. Utter, G. B. Brown, P. Beiersdorfer, E. J. Clothiaux, and N. K. Podder, "Grazing-incidence measurements of L-shell line emission from highly charged Fe in the soft x-ray region," Rev. Sci. Instrum. 70, 284-287 (1999).
    [CrossRef]
  23. Yu. Ralchenko, F.-C. Jou, D. E. Kelleher, A. E. Kramida, A. Musgrove, J. Reader, W. L. Wiese, and K. Olsen, "NIST atomic spectra database," version 3.1.1 (2007), http://physics.nist.gov/PhysRefData/ASD/lineslowbarform.html.
  24. R. L. Kelly, "Atomic and ionic spectrum lines below 2000 angstroms: hydrogen through krypton," J. Phys. Chem. Ref. Data 16, 1-1678 (1987).

2007 (6)

R. Katai, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Development of double-structure heavy-elements impurity pellet for active spectroscopy of high-temperature plasmas," Jpn. J. Appl. Phys. , Part 1 46, 3667-3669 (2007).
[CrossRef]

R. Katai, S. Morita, and M. Goto, "Identification and intensity analysis on forbidden magnetic dipole emission lines of highly charged Al, Ar, Ti and Fe ions in LHD," J. Quant. Spectrosc. Radiat. Transfer 107, 120-140 (2007).
[CrossRef]

R. Katai, S. Morita, and M. Goto, "Observation of visible and near-UV M1 transitions from highly charged Kr, Mo and Xe ions in LHD and its prospect to impurity spectroscopy for D-T burning plasmas," Plasma Fusion Res. 2, 1-4 (2007).
[CrossRef]

M. B. Chowdhuri, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Line analysis of EUV spectra from molybdenum and tungsten injected with impurity pellets in LHD," Plasma Fusion Res. 2, S1060 (2007).
[CrossRef]

M. B. Chowdhuri, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Spectroscopic comparison between 1200 grooves/mm ruled and holographic gratings of a flat-field spectrometer and its absolute sensitivity calibration using bremsstrahlung continuum," Rev. Sci. Instrum. 78, 023501 (2007).
[CrossRef] [PubMed]

Yu. Ralchenko, F.-C. Jou, D. E. Kelleher, A. E. Kramida, A. Musgrove, J. Reader, W. L. Wiese, and K. Olsen, "NIST atomic spectra database," version 3.1.1 (2007), http://physics.nist.gov/PhysRefData/ASD/lineslowbarform.html.

2005 (1)

A. M. Daltrini and M. Machida, "Modified branching ratio method for absolute intensity calibration in VUV spectroscopy," IEEE Trans. Plasma Sci. 33, 1961-1967 (2005).
[CrossRef]

2004 (1)

S. Morita, M. Goto, S. Masuzaki, H. Suzuki, K. Tanaka, H. Nozato, Y. Takeiri, J. Miyazawa, and LHD experimental group, "Effect of Ne glow discharge on ion density control in LHD," Plasma Sci. Tech. 6, 2440-2444 (2004).
[CrossRef]

2003 (4)

S. Morita, M. Goto, Y. Takeiri, J. Miyazawa, S. Murakami, K. Narihara, M. Osakabe, K. Yamazaki, T. Akiyama, N. Ashikawa, M. Emoto, M. Fujiwara, H. Funaba, P. Goncharov, Y. Hamada, K. Ida, H. Idei, T. Ido, K. Ikeda, S. Inagaki, M. Isobe, K. Itoh, O. Kaneko, K. Kawahata, H. Kawazome, K. Khlopenkov, T. Kobuchi, A. Komori, A. Kostrioukov, S. Kubo, R. Kumazawa, Y. Liang, S. Masuzaki, K. Matsuoka, T. Minami, T. Morisaki, O. Motojima, S. Muto, T. Mutoh, Y. Nagayama, Y. Nakamura, H. Nakanishi, Y. Narushima, K. Nishimura, A. Nishizawa, N. Noda, T. Notake, H. Nozato, S. Ohdachi, K. Ohkubo, N. Ohyabu, Y. Oka, T. Ozaki, B. J. Peterson, A. Sagara, T. Saida, K. Saito, S. Sakakibara, R. Sakamoto, M. Sasao, K. Sato, M. Sato, T. Satow, T. Seki, T. Shimozuma, M. Shoji, S. Sudo, H. Suzuki, N. Takeuchi, N. Tamura, K. Tanaka, K. Toi, T. Tokuzawa, Y. Torii, K. Tsumori, T. Uda, K. Y. Watanabe, T. Watari, Y. Xu, H. Yamada, I. Yamada, S. Yamamoto, T. Yamamoto, M. Yokoyama, Y. Yoshimura, and M. Yoshinuma, "Experimental study on ion temperature behaviors in ECH, ICRF and NBI H2, He and Ne discharges of the large helical device," Nucl. Fusion 43, 899-909 (2003).
[CrossRef]

H. Nozato, S. Morita, M. Goto, A. Ejiri, and Y. Takase, "Acceleration characteristics of spherical and nonspherical pellets by the LHD impurity pellet injector," Rev. Sci. Instrum. 74, 2032-2035 (2003).
[CrossRef]

M. Koike, K. Sano, E. Gullikson, Y. Harada, and H. Kumata, "Performance of laminar-type holographic grating for a soft x-ray flat-field spectrograph in the 0.7-6 nm region," Rev. Sci. Instrum. 74, 1156-1158 (2003).
[CrossRef]

M. May, J. Lepson, P. Beiersdorfer, D. Thorn, H. Chen, D. Hey, and A. Smith, "Photometric calibration of an EUV flat field spectrometer at the advanced light source," Rev. Sci. Instrum. 74, 2011-2013 (2003).
[CrossRef]

2002 (1)

G. V. Brown, P. Beiersdorfer, D. A. Liedahl, K. Widmann, S. M. Kahn, and E. J. Clothiaux, "Laboratory measurements and identification of the Fe xviii-xxivL-shell x-ray line emission," Astrophys. J. , Suppl. Ser. 140, 589-607 (2002).
[CrossRef]

2001 (1)

P. Beiersdorfer, S. von Goeler, M. Bitter, and D. B. Thorn, "Measurements of the 3d --> 2p resonance to intercombination line-intensity ratio in neon-like Fe xvii, Ge xxiii, and Se xxv," Phys. Rev. A 64, 032705 (2001).
[CrossRef]

1999 (3)

K. J. H. Phillips, R. Mewe, L. K. Harra-Murnion, J. S. Kaastra, P. Beiersdorfer, G. V. Brown, and D. A. Liedahl, "Benchmarking the MEKAL spectral code with solar x-ray spectra," Astron. Astrophys. , Suppl. Ser. 138, 381-393 (1999).

M. Koike, T. Yamazaki, and Y. Harada, "Design of holographic gratings recorded with aspheric wave-front recording optics for soft x-ray flat-field spectrographs," J. Electron Spectrosc. Relat. Phenom. 101-103, 913-918 (1999).
[CrossRef]

S. B. Utter, G. B. Brown, P. Beiersdorfer, E. J. Clothiaux, and N. K. Podder, "Grazing-incidence measurements of L-shell line emission from highly charged Fe in the soft x-ray region," Rev. Sci. Instrum. 70, 284-287 (1999).
[CrossRef]

1998 (1)

G. V. Brown, P. Beiersdorfer, D. A. Liedahl, K. Widmann, and S. M. Kahn, "Laboratory measurements and modeling of the Fe xvii x-ray spectrum," Astrophys. J. 502, 1015-1026 (1998).
[CrossRef]

1997 (1)

K. J. H. Phillips, C. J. Greer, A. K. Bhatia, I. H. Coffey, R. Barnsley, and F. P. Keenan, "Fe xvii x-ray lines in solar coronal and laboratory plasmas," Astron Astrophys. 324, 381-394 (1997).

1987 (1)

R. L. Kelly, "Atomic and ionic spectrum lines below 2000 angstroms: hydrogen through krypton," J. Phys. Chem. Ref. Data 16, 1-1678 (1987).

1984 (3)

N. Nakano, H. Kurada, T. Kita, and T. Harada, "Development of a flat-field grazing-incidence XUV spectrometer and its application in picosecond XUV spectroscopy," Appl. Opt. 23, 2386-2392 (1984).
[CrossRef] [PubMed]

W. L. Hodge, B. C. Stratton, and H. W. Moos, "Grazing incidence time-resolved spectrograph for magnetic fusion plasma diagnostics," Rev. Sci , Instrum. 55, 16-24 (1984).
[CrossRef]

C. De Michelis and M. Mattioli, "Spectroscopy and impurity behavior in fusion plasmas," Rep. Prog. Phys. 47, 1233-1346 (1984).
[CrossRef]

1973 (1)

J. H. Parkinson, "New observations of Fe xvii in the solar x-ray spectrum," Astron. Astrophys. 24, 215-218 (1973).

Appl. Opt. (1)

Astron Astrophys. (1)

K. J. H. Phillips, C. J. Greer, A. K. Bhatia, I. H. Coffey, R. Barnsley, and F. P. Keenan, "Fe xvii x-ray lines in solar coronal and laboratory plasmas," Astron Astrophys. 324, 381-394 (1997).

Astron. Astrophys. (2)

J. H. Parkinson, "New observations of Fe xvii in the solar x-ray spectrum," Astron. Astrophys. 24, 215-218 (1973).

K. J. H. Phillips, R. Mewe, L. K. Harra-Murnion, J. S. Kaastra, P. Beiersdorfer, G. V. Brown, and D. A. Liedahl, "Benchmarking the MEKAL spectral code with solar x-ray spectra," Astron. Astrophys. , Suppl. Ser. 138, 381-393 (1999).

Astrophys. J. (2)

G. V. Brown, P. Beiersdorfer, D. A. Liedahl, K. Widmann, and S. M. Kahn, "Laboratory measurements and modeling of the Fe xvii x-ray spectrum," Astrophys. J. 502, 1015-1026 (1998).
[CrossRef]

G. V. Brown, P. Beiersdorfer, D. A. Liedahl, K. Widmann, S. M. Kahn, and E. J. Clothiaux, "Laboratory measurements and identification of the Fe xviii-xxivL-shell x-ray line emission," Astrophys. J. , Suppl. Ser. 140, 589-607 (2002).
[CrossRef]

IEEE Trans. Plasma Sci. (1)

A. M. Daltrini and M. Machida, "Modified branching ratio method for absolute intensity calibration in VUV spectroscopy," IEEE Trans. Plasma Sci. 33, 1961-1967 (2005).
[CrossRef]

J. Electron Spectrosc. Relat. Phenom. (1)

M. Koike, T. Yamazaki, and Y. Harada, "Design of holographic gratings recorded with aspheric wave-front recording optics for soft x-ray flat-field spectrographs," J. Electron Spectrosc. Relat. Phenom. 101-103, 913-918 (1999).
[CrossRef]

J. Phys. Chem. Ref. Data (1)

R. L. Kelly, "Atomic and ionic spectrum lines below 2000 angstroms: hydrogen through krypton," J. Phys. Chem. Ref. Data 16, 1-1678 (1987).

J. Quant. Spectrosc. Radiat. Transfer (1)

R. Katai, S. Morita, and M. Goto, "Identification and intensity analysis on forbidden magnetic dipole emission lines of highly charged Al, Ar, Ti and Fe ions in LHD," J. Quant. Spectrosc. Radiat. Transfer 107, 120-140 (2007).
[CrossRef]

Jpn. J. Appl. Phys. (1)

R. Katai, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Development of double-structure heavy-elements impurity pellet for active spectroscopy of high-temperature plasmas," Jpn. J. Appl. Phys. , Part 1 46, 3667-3669 (2007).
[CrossRef]

Nucl. Fusion (1)

S. Morita, M. Goto, Y. Takeiri, J. Miyazawa, S. Murakami, K. Narihara, M. Osakabe, K. Yamazaki, T. Akiyama, N. Ashikawa, M. Emoto, M. Fujiwara, H. Funaba, P. Goncharov, Y. Hamada, K. Ida, H. Idei, T. Ido, K. Ikeda, S. Inagaki, M. Isobe, K. Itoh, O. Kaneko, K. Kawahata, H. Kawazome, K. Khlopenkov, T. Kobuchi, A. Komori, A. Kostrioukov, S. Kubo, R. Kumazawa, Y. Liang, S. Masuzaki, K. Matsuoka, T. Minami, T. Morisaki, O. Motojima, S. Muto, T. Mutoh, Y. Nagayama, Y. Nakamura, H. Nakanishi, Y. Narushima, K. Nishimura, A. Nishizawa, N. Noda, T. Notake, H. Nozato, S. Ohdachi, K. Ohkubo, N. Ohyabu, Y. Oka, T. Ozaki, B. J. Peterson, A. Sagara, T. Saida, K. Saito, S. Sakakibara, R. Sakamoto, M. Sasao, K. Sato, M. Sato, T. Satow, T. Seki, T. Shimozuma, M. Shoji, S. Sudo, H. Suzuki, N. Takeuchi, N. Tamura, K. Tanaka, K. Toi, T. Tokuzawa, Y. Torii, K. Tsumori, T. Uda, K. Y. Watanabe, T. Watari, Y. Xu, H. Yamada, I. Yamada, S. Yamamoto, T. Yamamoto, M. Yokoyama, Y. Yoshimura, and M. Yoshinuma, "Experimental study on ion temperature behaviors in ECH, ICRF and NBI H2, He and Ne discharges of the large helical device," Nucl. Fusion 43, 899-909 (2003).
[CrossRef]

Phys. Rev. A (1)

P. Beiersdorfer, S. von Goeler, M. Bitter, and D. B. Thorn, "Measurements of the 3d --> 2p resonance to intercombination line-intensity ratio in neon-like Fe xvii, Ge xxiii, and Se xxv," Phys. Rev. A 64, 032705 (2001).
[CrossRef]

Plasma Fusion Res. (2)

R. Katai, S. Morita, and M. Goto, "Observation of visible and near-UV M1 transitions from highly charged Kr, Mo and Xe ions in LHD and its prospect to impurity spectroscopy for D-T burning plasmas," Plasma Fusion Res. 2, 1-4 (2007).
[CrossRef]

M. B. Chowdhuri, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Line analysis of EUV spectra from molybdenum and tungsten injected with impurity pellets in LHD," Plasma Fusion Res. 2, S1060 (2007).
[CrossRef]

Plasma Sci. Tech. (1)

S. Morita, M. Goto, S. Masuzaki, H. Suzuki, K. Tanaka, H. Nozato, Y. Takeiri, J. Miyazawa, and LHD experimental group, "Effect of Ne glow discharge on ion density control in LHD," Plasma Sci. Tech. 6, 2440-2444 (2004).
[CrossRef]

Rep. Prog. Phys. (1)

C. De Michelis and M. Mattioli, "Spectroscopy and impurity behavior in fusion plasmas," Rep. Prog. Phys. 47, 1233-1346 (1984).
[CrossRef]

Rev. Sci (1)

W. L. Hodge, B. C. Stratton, and H. W. Moos, "Grazing incidence time-resolved spectrograph for magnetic fusion plasma diagnostics," Rev. Sci , Instrum. 55, 16-24 (1984).
[CrossRef]

Rev. Sci. Instrum. (5)

M. May, J. Lepson, P. Beiersdorfer, D. Thorn, H. Chen, D. Hey, and A. Smith, "Photometric calibration of an EUV flat field spectrometer at the advanced light source," Rev. Sci. Instrum. 74, 2011-2013 (2003).
[CrossRef]

H. Nozato, S. Morita, M. Goto, A. Ejiri, and Y. Takase, "Acceleration characteristics of spherical and nonspherical pellets by the LHD impurity pellet injector," Rev. Sci. Instrum. 74, 2032-2035 (2003).
[CrossRef]

M. B. Chowdhuri, S. Morita, M. Goto, H. Nishimura, K. Nagai, and S. Fujioka, "Spectroscopic comparison between 1200 grooves/mm ruled and holographic gratings of a flat-field spectrometer and its absolute sensitivity calibration using bremsstrahlung continuum," Rev. Sci. Instrum. 78, 023501 (2007).
[CrossRef] [PubMed]

M. Koike, K. Sano, E. Gullikson, Y. Harada, and H. Kumata, "Performance of laminar-type holographic grating for a soft x-ray flat-field spectrograph in the 0.7-6 nm region," Rev. Sci. Instrum. 74, 1156-1158 (2003).
[CrossRef]

S. B. Utter, G. B. Brown, P. Beiersdorfer, E. J. Clothiaux, and N. K. Podder, "Grazing-incidence measurements of L-shell line emission from highly charged Fe in the soft x-ray region," Rev. Sci. Instrum. 70, 284-287 (1999).
[CrossRef]

Other (1)

Yu. Ralchenko, F.-C. Jou, D. E. Kelleher, A. E. Kramida, A. Musgrove, J. Reader, W. L. Wiese, and K. Olsen, "NIST atomic spectra database," version 3.1.1 (2007), http://physics.nist.gov/PhysRefData/ASD/lineslowbarform.html.

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Figures (16)

Fig. 1
Fig. 1

Schematic and design specifications of 2400 grooves / mm EUV flat-field spectrometer.

Fig. 2
Fig. 2

Calculated focal curves (solid curves) of 2400 grooves / mm VLS concave grating as a parameter of angle of incidence. Focal curves denoted with each incidence angle are indicated by solid curves. Definition of vertical (X) and horizontal (Y) axes is shown in Fig. 1. Solid vertical line denoted with CCD position indicates design position of linear image focus. Dashed lines indicate the wavelength position denoted with each wavelength in Å.

Fig. 3
Fig. 3

Experimental and theoretical reciprocal linear dispersions as a function of wavelength. Experimental data plotted with solid circles are fitted with the dashed curve. Theoretical values are traced with the solid curve.

Fig. 4
Fig. 4

Experimentally obtained spectral resolution Δ λ o (full width at spectral foot position) at three wavelengths of 18   Å (open circles + dotted curve), 33   Å (open squares + solid curve), and 67   Å (open triangles + dashed curve) for holographic grating as a function of distance from designed linear focal position. Value of Δ Y = 0 ( Y = 235   mm ) means detector surface is set just on the designed linear focal position (also see Fig. 1).

Fig. 5
Fig. 5

Typical EUV spectra with (a) ruled and (b) holographic 2400 grooves / mm gratings from NBI-heated LHD plasmas.

Fig. 6
Fig. 6

Experimentally obtained spectral resolution Δ λ o for ruled and holographic gratings as a function of wavelength.

Fig. 7
Fig. 7

Examples of Gaussian fitted line profile (solid curve) of C vi ( 33.73   Å ) show spectral resolution (FWHM: full width at half-maximum) Δ λ for (a) ruled and (b) holographic gratings (solid circles: experimental data). Determined spectral resolution at FWHM, Δ λ , is expressed in units of channel and angstroms.

Fig. 8
Fig. 8

EUV spectra from LHD discharges obtained for (a) ruled and (b) holographic gratings representing higher order C vi emissions. All the data are normalized to the first-order light of C vi at 33.73   Å .

Fig. 9
Fig. 9

Calculated (solid curve) and experimental (solid circles fitted with dashed curve) EUV bremsstrahlung continuum as a function of wavelength for (a) ruled and (b) holographic gratings.

Fig. 10
Fig. 10

Variation of relative sensitivities against wavelength for ruled (dashed curve) and holographic (solid curve) gratings. Both data are normalized at 93.92   Å . It should be noted that absolute sensitivity is much different between ruled and holographic gratings.

Fig. 11
Fig. 11

Absolute sensitivity of 2400 grooves / mm EUV spectrometer with ruled (dashed curve) and holographic (solid curve) grating as a function of wavelength. Data points (solid circles) with error bars are obtained from absolutely calibrated 1200 grooves / mm EUV spectrometer. Please note that spectrometer sensitivity is the inverse of calibration factor.

Fig. 12
Fig. 12

Fe xviixxiv EUV spectrum of n = 2 3 transitions from L-shell partially ionized Fe in LHD plasma ( n e = 9 × 10 13 cm 3 , T e = 0.7   keV ). Symbols denoted with * indicate blended lines as discussed in text. Ne EUV spectrum in (b) is shown as a marker of wavelength.

Fig. 13
Fig. 13

Ti xiiixx EUV spectrum of n = 2 3 transitions from L-shell partially ionized titanium in LHD plasma with Ti impurity pellet injection ( n e = 1.8 × 10 13 cm 3 , T e = 2.3   keV ). Symbols denoted with * indicate blended lines as discussed in text.

Fig. 14
Fig. 14

EUV spectrum in 20 65   Å of H- and He-like ions from low-Z impurities in LHD with boron–nitride impurity pellet injection.

Fig. 15
Fig. 15

Comparison between EUV spectra in 5 0 1 3 0   Å simultaneously recorded from two flat-field spectrometers of (a) EUV_Short ( 2400 grooves / mm for 1 0 1 3 0   Å measurement) and (b) EUV_Long ( 1200 grooves / mm for 5 0 5 0 0   Å measurement).

Fig. 16
Fig. 16

Comparison of (a) spectral resolution (FWHM) and (b) absolute sensitivity between two EUV spectrometers: EUV_Short ( 2400 grooves / mm for 1 0 1 3 0   Å measurement) and EUV_Long ( 1200 grooves / mm for 5 0 5 0 0   Å measurement). (a) Solid (open) circles and (b) solid (dashed) curve represent data from EUV_Short (EUV_Long).

Tables (2)

Tables Icon

Table 1 Observed n = 2–3 Transitions of L -Shell Partially Ionized Fe Ions in 10–20 Å a

Tables Icon

Table 2 Observed n = 2–3 Transitions of L -Shell Partially Ionized Ti Ions in 10–30 Å a

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