10/21/03H.J. Krebs1 LST Mechanical Design Review Brass Absorber Design H.J. Krebs October 21, 2003

10/21/03H.J. Krebs2 Brass Absorber Design - General Requirements –Provide minimum of 5.25” total radial thickness of brass absorber material Six layers.875” in thickness replacing IFR layers 5,7,9,11,13 & 15 –Brass material shall be Leaded Muntz Metal, UNS C ; Admiralty Brass (Antimonial), UNS C-44400; Admiralty Brass (Phosphorized), UNS C-44500; or Naval Brass (Uninhibited), UNS C-46400, or an equivalent alloy. –Forces induced by the brass dead load shall not inhibit the installation of the LST detectors – i.e., reduce steel gaps (see Nancy Yu’s talk) –Additional detector weight related to brass shall not compromise the detector earthquake design (see Les Dittert talk)

10/21/03H.J. Krebs3 Brass Absorber Design Brass absorber purchase split into 2 phases –Phase I Top and bottom sextants – 24.8 tons total (including spares) Needed by April 1, 2004 –Pre-installation preparation Material specification and detail drawings complete Steel gap corner conditions designed and parts detailed Purchased by DOE (SLAC) –Out for RFP on 10/9/03 –Proposal to be opened 10/29/03 –Phase II Side sextants – 47.9 tons total (including spares) Needed by January 1, 2005 –Pre-installation preparation Material specification and detail drawings complete Steel gap corner conditions still under consideration Purchased by INFN –Monies have been allocated –In INFN procurement cycle

10/21/03H.J. Krebs4 Brass Absorber Design (Phase I)

10/21/03H.J. Krebs5 Brass Absorber Design (Phase I)

10/21/03H.J. Krebs6 Brass Absorber Design (Phase I)

10/21/03H.J. Krebs7 Brass Absorber Design (Phase I) Each layer consists of 14 brass plates (84 plates per sextant) 7/8” thick and 10.5” in depth installed in the difficult direction to minimize steel plate deflection Plates are cambered such that each plate is flat to within ±.060” when simply supported at the four corners –Actual amount of camber determined by fabricator Range of possible Z misalignment: –3.4” to 8.8” depending on tolerances Aluminum wedge fillers prevent binding in gap corners Brass plate cannot turn in gap beyond 5.9° Corners radiused ¼” R to prevent the plate from binding with wedge fillers from Z angular misalignment

10/21/03H.J. Krebs8 Brass Absorber Design (Phase II) Each layer consists of 14 brass plates (84 plates per sextant) 7/8” thick and 10.5” in depth installed in the difficult direction to minimize steel plate deflection Plates shall be flat to ±.060” in the as-rolled condition assuming no effect by gravity Range of possible Z misalignment yet to be determined –Depends on steel gap corner conditions Design of remaining Phase II components complete on January 5, 2004

10/21/03H.J. Krebs9 Conclusions Brass absorber needed for 2004 is designed and is in the SLAC RFP process –Supporting hardware design is complete and fabrication is underway Brass absorber needed for 2005 is designed and proceeding through the INFN procurement process –Supporting hardware design begins Our goal is to have the absorber material in hand with all pre-installation preparation complete as early as possible to take advantage of any potential schedule advancement –PEP machine breakage