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# Definition of orientation angles, Tilt, Slope, and Rotate.

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A user interface (either NISP_Win as shown, or MC_Web) writes an Instrument Geometry File with all Surfaces, Regions, and Parameters. The Monte Carlo engine MC_Run performs the simulation, using algorithms from the subroutine library MCLIB. ABSTRACT The Neutron Instrument Simulation Package (NISP) performs complete source-to-detector simulations of...

## Context in source publication

Context 1
... from McStas. This is the first element in NISP that is not axially symmetric, so it was necessary finally to define the third Euler angle as an extrinsic parameter. We define orientation as 1) Tilt, rotation about the Y-axis; 2) Slope, rotation about the tilted X-axis; 3) Rotate, rotation about the tilted and sloped Z-axis. This is illustrated in Fig. ...

## Citations

... One notoriously known limiting factor for reconciling and interpreting neutron scattering data from different instruments is the fact that the energy resolution function of a given instrument depends not only on the instrument parameters but also on the imparted momentum Q and energy E to the sample. Therefore, while qualitative interpretation of the raw INS data is generally possible (peak positions, dispersive nature of the excitations etc.), any rigorous quantitative analysis of INS data (excitation lifetimes, BEC fraction etc.) requires an accurate knowledge of the resolution function R i (Q, E) [9,10,11,8]. ...
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