Development of the Soft X‐ray AGM–AGS RIXS beamline at the Taiwan Photon Source. (30th March 2021)

• Record Type: Journal Article
• Authors: Singh, A.; Huang, H. Y.; Chu, Y. Y.; Hua, C. Y.; Lin, S. W.; Fung, H. S.; Shiu, H. W.; Chang, J.; Li, J. H.; Okamoto, J.; Chiu, C. C.; Chang, C. H.; Wu, W. B.; Perng, S. Y.; Chung, S. C.; Kao, K. Y.; Yeh, S. C.; Chao, H. Y.; Chen, J. H.; Huang, D. J.; Chen, C. T.
• Is Part Of: Journal of synchrotron radiation. Volume 28:Part 3(2021)
• Page Start: 977
• Page End: 986
• Publication Date: 2021-03-30
• Subjects: soft X‐ray beamline -- soft X‐ray optics -- grating monochromator -- active grating -- resonant inelastic X‐ray scattering -- soft X‐ray spectra; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577521002897
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : The development of a high‐resolution and highly efficient beamline for soft X‐ray resonant inelastic X‐ray scattering (RIXS) located at the Taiwan Photon Source is reported. Abstract : We report on the development of a high‐resolution and highly efficient beamline for soft X‐ray resonant inelastic X‐ray scattering (RIXS) located at the Taiwan Photon Source. This beamline adopts an optical design that uses an active grating monochromator (AGM) and an active grating spectrometer (AGS) to implement the energy compensation principle of grating dispersion. Active gratings are utilized to diminish defocus, coma and higher‐order aberrations, as well as to decrease the slope errors caused by thermal deformation and optical polishing. The AGS is mounted on a rotatable granite platform to enable momentum‐resolved RIXS measurements with scattering angles over a wide range. Several high‐precision instruments developed in‐house for this beamline are described briefly. The best energy resolution obtained from this AGM–AGS beamline was 12.4 meV at 530 eV, achieving a resolving power of 4.2 × 10 4, while the bandwidth of the incident soft X‐rays was kept at 0.5 eV. To demonstrate the scientific impact of high‐resolution RIXS, we present an example of momentum‐resolved RIXS measurements on a high‐temperature superconducting cuprate, i.e. La2– x Sr x CuO4 . The measurements reveal the A1 g buckling phonons in superconducting cuprates, opening a new opportunity to investigate the coupling between these phonons and charge‐density waves.