Collider Quadrupole Magnet (CQM) Optical Alignment Window Heat Leak Prediction

Abstract

The additional static heat leak to the cryogenic refrigeration systems of an SSC Collider Quadrupole Magnet (CQM) due to the Optical Alignment Window apparatus was calculated for three configurations: (1) panes in the 20K shield, 80K shield, and vacuum vessel, (2) empty aperture in the 20K shield and panes in the 80K shield and vacuum vessel, and (3) empty apertures in both the 20K and 80K shields and a pane in the vacuum vessel only. In addition, two cases for pane infrared optical coating configuration were simulated: (1) coating on both sides of a pane and (2) coating on the top side of a pane only. For a four windows per magnet design, the results of the analysis show that the 4K and the 20K total static heat leak budgets will be exceeded only for the empty apertures in both of the shields configuration. This result applies for a single side or double sided coated pane. The existing baseline configuration (no 20K shield pane, pane in 80K shield, pane top side coated) is sufficient to meet the CQM total static heat leak budget.