BL-2A Undulator Soft X-Ray Double-Crystal Monochromator Station

Spokesperson :Yoshinori KITAJIMA

1. Outline

BL-2A provides soft X rays in the energy range between 1.8 keV and 5.0 keV with a double-crystal monochromator from an undulator U#02 source (l = 6 cm, 60 periods, K = 2.24 - 0.18). As a benefit of the prominent characteristics of high brilliance of the undulator source, high flux beams in a small spot with a high resolving power are easily obtainable. Users can tune the undulator gap at any time during their experiments where the photon energy of the first harmonics varies between 290 eV and 973 eV during 2.5-GeV operation. The 3rd or higher harmonics can be used at BL-2A. There is another station BL-11B for a similar energy region but at a bending-magnet source, which is suitable EXAFS measurements on Si, P, S, and Cl.

Layout of BL-2A
Fig. 1: Optics of BL-2A.

2. Performance

OpticsDouble-Crystal Monochromator [Si(111) or InSb(111)]/Focusing Mirrors
Energy Range2082 eV - 5000 eV [Si(111)] or 1745 eV - 3700 eV [InSb(111)]
Resolving PowerE/dE = 5000 - 8000 [Si(111)] or ca. 2000 [InSb(111)]
Spot Sizeca. 1 mm (H) x 1 mm (V)
Photon Fluxmaximum ca.2 x 1011 photons/s

Spectrum of BL-2A
Fig. 2: Example spectral distribution form the Si(111) monochromator.

Spectrum of [S<sub>2</sub>O<sub>3</sub>]<sup>2-</sup>
Fig. 3: Sulfur K-edge total electron yield apectra of [S2O3]2-. Energy resolution is much higher than BL-11B.

3. Equipments

4. Remarks

Spectrum under previous and present emittance
Fig. 4: Change in undulator spectrum by the emittance reduction of the PF ring in 1998. The peak intensity of the 5th harmonics becomes ca. 2.4 times as before with a small aperture. It is ca. 1.5 times higher when a larger aperture is used.

5. References

  1. H. Maezawa et al., Rev. Sci. Instrum., 60, 1889 (1989).
  2. Y. Kitajima et al., Rev. Sci. Instrum., 63, 886 (1992).
  3. Y. Kitajima, J. Elec. Spectrosc. Relat. Phenom., 80, 405 (1996).
  4. Y. Kitajima, J. Synchrotron Rad., 6, 167 (1999).

6. Publications

List of publications those registered to PF publication database is available.

Last modified: March 28, 2005.