Objectives During the late 1980‟s and early 1990‟s, tremendous improvements were made in the fabrication of neutron mirrors. These new coatings allow the building of guide systems which can increase neutron flux by a factor 3 to 4. More recently these improved supermirrors have been implemented in a range of optical devices such as trumpet guides, ballistic guides and polarizing benders, and have permitted major improvements to existing spectrometers. Our challenge is now to go even further and increase the luminosity of neutron spectrometers even more. We believe that the neutron optics technology and components that are presently available will enable the design of new spectrometers which can be at least 10 times brighter than the existing ones. The principles that will be demonstrated could easily be implemented at other facilities. The outcome will be a more efficient use of the existing neutron sources. This would be of direct benefit to neutron users in the short term. We propose to focus on 2 main objectives: (i) High flux reflectometry, (ii) Focussing optics. Each thematic task gathers instrument scientists who are experts in their fields (reflectometry, SANS, diffraction or imaging) and who have a direct interest in improving their spectrometers. Most of the proposed developments will be implemented on existing spectrometers in the short term. The achieve these innovative technical solutions will require technical developments which will in general be of benefit to several tasks. Most of the optics developments require advanced numerical simulations. Monte-Carlo simulation programs will be upgraded or rewritten to include new advanced components and optimization tools. This will also be of benefit to a wide community. Tasks More info on the Task section Click to enlarge the pictures Task 17.2: High flux reflectometry and energy analysis New concepts for neutron reflectometers. To maximize the use of the neutrons available in the guide by performing reflectivity measurements in parallel for all wavelengths. Sub-Task 17.2.1: Compact Energy Analyzer Design of an energy analyzing device based on reflective optics. Sub-Task 17.2.2:Refraction-encoded reflectometry We propose to use neutron prisms with a very good flatness, using the contrast in scattering length density between air and the prism material to build an energy analysis device. Sub-Task 17.2.3: Wavelength-encoding by Bragg diffraction To place many diffracting crystals in the reflected beam, diffracting the different wavelengths in different directions onto a position-sensitive detector, such that the wavelength is encoded in the position on the detector. Task 17.3: Advanced Focusing Techniques Sub-Task 17.3.1: Multichannel focusing guide To use the Monte-Carlo simulation tools McStas and/or VITESS, which currently do not support multi-channel tapered focusing guides. Sub-Task 17.3.2: Adaptive Optics for extreme EnvironmentsUse of elliptic focusing guides at regular neutron beam lines. Resolving problems by means of focusing guides with adaptive optics. Sub-Task 17.3.3: High resolution imaging using reflective optics - To demonstrate by means of Monte-Carlo calculations that elliptic neutron guides only lead to minor distortions of the phase space and can thus be efficiently implemented for neutron radiography and tomography. - To develop focusing devices using a nested Wolter-type mirror system and advanced supermirror technology. Sub-Task 17.3.4: Focusing SANS To propose flexible optics to optimize SANS spectrometers by using focusing optics Task 17.4: Monte-Carlo simulations of complex optics Sub-Task 17.4.1: Modelling of interacting optical elements. Monte-Carlo simulations tools . To develop a high-level structure in McStas which allows subparts to interact with each other in a non sequential way. Sub-Task 17.4.2 : Optical simulation work bench To coordinate the many simulation efforts, to avoid duplicated work, to assist in testing and documenting new features, and to organize “component development” workshops.

Coordinator: Ott Frédéric Forum: WP17 Neutron Optics FORUM (restricted access to the W17 neutron Optics JRA Partners) Link to the JRA Neutron Optics under FP6 2004 - 2008