1. MICE Meeting at Columbia University Absorber windows design comparisons E.L.Black/IIT June/2003

2. Consideration for selecting the window design for the liquid hydrogen absorber and enveloping vacuum chamber Non Welded 1.Allows the use of dissimilar material 2.May need enlargement of the focusing magnet bore 3.Will require larger Absorber vacuum window 4.Require extra test at cryo temperatures 5.Handling of delicate windows considerations, offer the possibility of changing windows only. 6.Windows will be reusable in a short time 7.Repeatable or modifiable absorber length 8.Facilitate hydrogen leak early detection Welded 1.Require R&D for welding dissimilar materials 2.Current Focusing magnet bore can be use 3.Absorber vacuum and hydrogen windows can be of same size 4.Welds qualification and cryo tests (micro cracking considerations) 5.Handling welded assemblies require extra precautions 6.Windows & absorber bodies may not be reusable 7. If windows are reused, hydrogen length will change depending on design 8. Fabrication, measurement and testing of thin windows for welding are relative expensive

4. NON WELDED 1. Current effort on the design of windows with other than aluminum is in progress - The material preferred for the absorber body with best heat transfer characteristics is aluminum 6061-T6 2. The preliminary lay out on the previous slide indicate changes are required on the geometry of the focusing coils farther studies are needed for final conclusions 3. To remove the absorber window, after removing the vacuum window, we need the vacuum window ID to be larger than the OD of the absorber window 4. The functional performance of the absorber seal shall be tested at cryo temperatures 5. Extra precautions will be required to handle the absorber and vacuum assembled with delicate windows 7. There will be no material removed, from the windows or the absorber chambers that would change the hydrogen length 8. The intended double seal arrangement will allow an early hydrogen leak detection for immediate shot down.

6. WELDED 1. Welding of thin windows of equal or dissimilar materials will require R&D 2. Layouts to verify no changes on current focusing magnet geometry are in progress 3. Absorber and vacuum windows of the same size (if possible) would facilitate production 4. Windows for welding require fixturing for handling from fabrication to welding, testing, installation and for changing if not disposed 5. Tests of the assembled welded windows shall extend beyond the codes with thermo cycling to assure quality of welds 6. To reuse welded absorber assemblies a complete test as if it would be new shall be perform 7. The design of welded windows with the intension of reusing, shall include the removal of material affected by the previous weld 8. Cost of this window is affected by the set up for machining, measurement, testing and welding