A Replacement Cold Neutron Guide System for HFIR (Conceptual Design Report)

Ray-Tracing Simulations Characterising the Performance of the Proposed 2024 HFIR HB4 Main Shutter

“…The baseline geometry and reflectivity for the Main Shutter guide channels can be determined via the Wavelength and Divergence requirements for each instrument [1]…”

“…The optical requirements within the shutter are determined by what the source can provide through the primary collimator and what the instruments need to meet their science goals. Those needs are dictated by the minimum neutron wavelength and maximum beam divergence on the sample, as noted in [1]. A summary of these requirements is seen in Table 2.…”

“…Table 2. The baseline geometry and reflectivity for the Main Shutter guide channels can be determined via the Wavelength and Divergence requirements for each instrument [1]. Based on these requirements, combined with the location of the Main Shutter and the phase space permitted by the beamtube collimator, one can layout a geometry that will meet almost all of the instrument requirements seen in Table 2.…”

“…Based on these requirements, combined with the location of the Main Shutter and the phase space permitted by the beamtube collimator, one can layout a geometry that will meet almost all of the instrument requirements seen in Table 2. The assignments of each instrument to a certain channel was based on layout in the guide hall and sensitivity to guide curvature disruptions; details regarding this feature of the instrument layout are documented in [1]. One can see the collimator exit flux distribution and source to shutter distance in Figure 5, which dictates the permitted range of guide channels and allowed angular acceptance.…”