Abstract Details
| Name: Vinita Navalkar Affiliation: Tata Institute of Fundamental Research Conference ID: ASI2017_999 Title : DEVELOPMENT OF SPUTTERING SYSTEM FOR FABRICATION OF THIN FILM MULTILAYER OPTICS OF HARD X-RAY TELESCOPE. Authors and Co-Authors : K. P. Singh, H. Shah, V. Mhatre, J. G. Koyande. Tata Institute of Fundamental Research Abstract Type : Poster Abstract Category : Instrumentation and Techniques Abstract : In the visible spectrum, most materials used for reflection have the refractive index greater than 1, while for x-rays this index is slightly less than 1, for all materials. The reflectivity for highly energetic X-ray photons is negligible at normal incidence. Therefore, the imaging optics in x-rays make use of total external reflection at grazing incidence angle. Furthermore, the critical angle for the total external reflection depends on the energy of the incident X-rays. This puts a practical limit on the design of x-ray reflective optics working at high energies (E >15 keV). Solution to this problem is the development of multilayer-coated mirror surfaces. Reflectance at angles greater than the critical grazing angle can be achieved by using depth-graded multilayer coatings on the mirror surfaces. Thin film multilayer coatings of materials having high and low atomic number Z are deposited on glass substrates. These multilayered mirrors satisfy the satisfy Bragg’s equation mλ=2dsinƟ, thus increasing the reflectivity range and extending the imaging capabilities to a wide band of energies in the hard X-ray regime. Sputtering being an effective technique for deposition of thin films, RF Magnetron Sputtering System has been used to fabricate such multilayered mirrors. We present here the work done for developing such multilayered mirror systems and the characterizing the sputtering system using single layered structures. |