Double - crystal monochromator with ultra-sonically adjustable reflectivity.

• Grant number: 96/03343-9
• Support Opportunities: Regular Research Grants
• Start date: November 01, 1996
• End date: November 30, 1998
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Igor Polikarpov
• Grantee: Igor Polikarpov
• Host Institution: Associação Brasileira de Tecnologia de Luz Síncrotron (ABTLuS). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil

Abstract

A new type of double crystal X-ray monochromator system is suggested that provides significantly higher flux than standard perfect double crystal monochromators at a given bandwidth, and in addition permits dynamical adjustment of the energy resolution. The new monochromator system is based on excitation of perfect crystals by ultrasonic waves (USW), the reflected intensity of which increases continuously with increasing USW amplitude. This monochromator system is of potential interest for applications which require highest possible flux and variable energy resolution, e.g., in anomalous absorption, anomalous diffraction studies, scattering or diffraction experiments using synchrotron radiation. Preliminary experimental and theoretical investigations of USW influence on the diffraction of X-rays in a double-crystal arrangement have been performed. Results of the experiments show that it is possible to increase several times the over-all reflectivity of such a system as compared with the monochromator without USW excitation (Polikarpov, Panov & Bartunik, 1994). Here, we suggest to investigate experimentally the possibility of creating a double crystal monochromator system for synchrotron radiation, which uses USW excitation for dynamical adjustment of the over-all reflectivity and energy resolution over a wide range. (AU)