Synchrotron Utilization Section

Soft X-ray Applications Lab (SXAL)                                                                              Publications

The SXAL is looking after two beamlines of soft x-ray reflectivity techniques installed on Indus-1 (BL-04) and Indus-2 (BL-03). The lab provides support to the users of soft x-ray reflectivity experiments for reflectivity, absorption and transmission measurements in the photon energy range of 10-300 eV and 100- 1500 eV. Besides that the lab is engaged in development of in-house technology for refurbishing x-ray optical components by removing carbon contamination layer from the optics surface. In synchrotron environment a carbon contamination layer grows on optical surfaces which deteriorates the optics performances, resultantly the optics needs to be refurbished. The lab is involved in various research activities also pertaining to soft x-ray reflectivity, and soft x-ray absorption properties of various materials.

Major Activities
  • Support beamline users on Indus-1 and Indus-2 soft x-ray reflectivity beamlines.
  • Design and development of synchrotron optics refurbishing technology.
  • Studies on plasma/laser/ and UV interaction with different allotropes of carbon in perspective of synchrotron optics cleaning.
  • Studies on soft x-ray optical behavior of various oxides, carbides and compound materials. Role of core hole and core exciton in soft x-ray optical properties of various materials.
  • Soft x-ray resonant reflectivity for nondestructive structural and compositional analysis.
Synchrotron optic cleaning activity

Deposition of carbon layer on x-ray optical elements in beamline environment is a serious problems as it deteriorates the optics performance. In order to remove the contamination layer from optics surface an optics cleaning facility is developed. Depending on the types of contamination and optics size three differ techniques can be used.

For medium size mirrors a radio frequency based plasma system is in-house developed. The system equipped with optical emission spectrometer for online recording of optical emission lines, mass flow controllers and dynamic pumping system. Carbon from different sample of Pt/C, Mo/C, W/C and Au/C sample are removed successfully without damaging the optical coating. Pre mirror of reflectivity beam line of Indus-1 was cleaned using this system. Presently the system can accommodate 340 mm ×100 mm size mirrors. For large size optics an RF plasma bases system is under development.

Au mirror of reflectivity beamline, Indus-1 before and after cleaning.
Au mirror of reflectivity beamline, Indus-1 before and after cleaning.

Photograph and schematic view of In-house developed RF (13.56 MHz) plasma cleaning system. Ar and O2 are used as feed stock gases for plasma generation.
Photograph and schematic view of In-house developed RF (13.56 MHz) plasma cleaning system. Ar and O2 are used as feed stock gases for plasma generation.
Photograph and schematic view of In-house developed RF (13.56 MHz) plasma cleaning system. Ar and O2 are used as feed stock gases for plasma generation.

Xenon and Hg UV lamp of 172 nm and 185 to 254 nm wave length respectively are available for removing the carbon contamination. The optics is irradiated by UV light at optimum distance from source and time. A toroidal mirror of dimension about 150 mm x 30 mm of AIPES beamline is uniformly cleaned by irradiating it for 9 hrs.

Pt mirror of AIPES beamline, Indus-1 before and after cleaning by UV light irradiation.
Pt mirror of AIPES beamline, Indus-1 before and after cleaning by UV light irradiation.

Yb doped fiber laser of 1064 nm wavelength is installed in SXAL. The laser can be used for large size optics cleaning. The laser head can scan 150 mm × 150 mm area. The laser has provision of varying scan speed, repetition frequency, focus point and power. The optimum power of laser is 30 watts.

Fiber laser system for carbon removal experiments.
Fiber laser system for carbon removal experiments.

Synchrotron optics cleaning recent work

Photograph of Au coated spherical mirror of soft x-ray reflectivity beamline BL-03, Indus-2 before (left) and after (right) RF plasma cleaning.
Photograph of Au coated spherical mirror of soft x-ray reflectivity beamline BL-03, Indus-2 before (left) and after (right) RF plasma cleaning.
Photograph of Au coated spherical mirror of soft x-ray reflectivity beamline BL-03, Indus-2 before (left) and after (right) RF plasma cleaning.
Photographs of spherical grating of Photophysics beamline BL-05, Indus-1 taken (left) Before and (right) After UV cleaning experiments
Photographs of spherical grating of Photophysics beamline BL-05, Indus-1 taken (left) Before and (right) After UV cleaning experiments




Team Members
  1. Dr. Mohammed H. Modi, SO/H
  2. Shri Praveen Kumar Yadav, SO/F
  3. Shri Rajkumar Gupta, SO/D
  4. Shri Pushkardeep, SA/C
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