Multiple-stage tapered neutron guide as a broad band focusing system

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)22_Publication in policy or professional journal

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Original languageEnglish
Article number9
Pages (from-to)86-96
Journal / PublicationProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2004
Externally publishedYes


TitleAdvances in Computational Methods for X-Ray and Neutron Optics
PlaceUnited States
CityDenver, CO
Period3 - 5 August 2004


Neutron guides are widely used for improving the angular aperture of neutron scattering instruments in a broad band of wavelength. However, the usual guides are not effective enough in the short wavelength range. This is especially critical for time-of-flight instruments, which cannot take advantage of focusing techniques designed for steady-state monochromatic instruments. We discuss alternative ways to shape the reflecting surfaces in order to obtain a maximum angular aperture at the sample position at the expense of beam cross-section reduction. An optimal piecewise solution is proposed and Monte Carlo simulations with the IDEAS package are presented. Simulations for General Purpose Powder Diffractometer (GPPD) at Argonne National Laboratory are presented and the impact of a vertically focusing multiple-stage tapered guide is discussed. The results obtained by simulating the guide system options of engineering diffractometer VULCAN at the Spallation Neutron Source (SNS) are also presented, including vertically and horizontally tapered guide sections. The optimal multi-stage tapered guide design is discussed in terms of instrument figure of merit corresponding to different experimental needs ranging from high Q resolution to high intensity and/or high spatial resolution.

Research Area(s)

  • Focusing, Monte Carlo simulations, Neutron optics, Neutron scattering instruments, Tapered guide