SLAC RC Status Report US LHC Accelerator Research Program BNL - FNAL- LBNL - SLAC SLAC RC Status Report 20 September 2010 LHC Collimation Working Group Meeting Tom Markiewicz/SLAC

Reminder: Last Slide from 30-August-2010 With 4 of 7 rolled pins replaced with solid stainless pins, the clamp, thrust bearings, stainless bearings Pawl fails at 150 inch-pounds torque Rolled pin holding first bevel gear shears at 204 inch-pounds Immediate plan: improve L drive unit Replace rolled pins on ratchet axle with solid stainless Replace pawl with a more classic design where a radial spring causes a “dog” to engage ratchet tooth Test unit to ~400 inch-pounds Then implement these changes on R unit and test it Then final assembly & welding & testing & alignment in clean-room using ion-deposited W-S2 parts . Then bake out & ship. LHC CWG - 20 September 2010 RC Status - T. Markiewicz

01-September: Geneva Drive Axle Breaks at ~300 inch-pounds of torque LHC CWG - 20 September 2010 RC Status - T. Markiewicz

Drive Rebuilt: tested 16 Sept → >440 inch-pounds Add Large Thrust Bearing at end of Axle to prevent bending Exchange Geneva Drive for Pair of 1:1 Gears (load reduced x3) 5mm Moly shaft (& two bearing sets) -> 6mm Steel (& larger bearing sets) LHC CWG - 20 September 2010 RC Status - T. Markiewicz

RC Status - T. Markiewicz Safety Factor 30 in-# to bend each ~1m tube 360 degrees 40 in-# to rotate jaw on moly split ring 1mm ceramic ball support 100 in-# total in this configuration LHC CWG - 20 September 2010 RC Status - T. Markiewicz

RC Status - T. Markiewicz Next Steps Switch out primary support bearing for 20mm/42mm Steel Anticipate friction torque will go to ~ zero and increase safety factor Mount new “pawl” Decide on Geneva vs. gear Decide on Steel vs. Ceramic main bearing Assemble, weld, test & ship LHC CWG - 20 September 2010 RC Status - T. Markiewicz