The cooling channel for a muon collider or neutrino source may utilize thin beryllium windows situated between cells of RF cavities.  The windows for an 800 MHz design are composed of 16 cm diameter circular foils of 127 micron thickness.  These windows undergo significant ohmic heating from RF power, and displace out of plane.  This displacement causes the cavities to detune, and must be controlled.  In order to evaluate different window designs, an FEA model was created in ANSYS, and this model was correlated to windows tested in the laboratory.  The models discussed in this paper are an extension of previous work [3], now incorporating pre-stress effects which are induced in the foil during cool down from brazing.  Using empirically validated models, several other window designs are analyzed, including windows of different thicknesses, non-constant thickness windows ("stepped" designs), windows with surface ribbing, and windows of diameters much larger than 16 cm (up to 42 cm diameter).  These alternative designs are also subjected to expected RF power loads, and their prospects for operating within strict mechanical tolerances are judged.


Posted muc0180.pdf to WWW
URL http://www-mucool.fnal.gov/mcnotes/muc0180.pdf
Posted by Hartman