Mechanical Engineering Design Review BL ARPES Endstation Derek Yegian, Jonathan Denlinger, Keith Franck 4/18/2008

Beamline 3D Layout M302 Entrance slit Monochromator M303G301G302 G302 (temp) Exit slit M321/M331 M332M333 M322M323 RIXS ARPES TOF Gas Cell

Endstation Layout M332M333 M322M323 RIXS ARPES TOF (2-bunch only) 44”

ARPES – Phase 1 (Sept. Installation) Fixed Spool Sample rotation 2-part rotary Analyzer Fixed, horizontal Turntable Locked in place Beam

Support Structures (a) Two independent supports –A) Vertical load (~2000 lbs) of chamber/analyzer carried through SKF spherical plain bearing on base plate

Support Structures (b) Two independent supports –B) Horizontal load and moments carried through six-strut assembly »Minor vertical load of tabletop and ancillary structure

Chamber Assembly (a) Vertical rotation Alignment Goal: Top chamber flange to rotate with 20 micron sphere of confusion (1) Turntable on top plate -- turntable rests on angled surface of cam bearings (2) Align bottom bushing to turntable rotation axis using dial indicator

Chamber Assembly (b) Vertical rotation Alignment (3) Install pumping base and top chamber through the turntable (4) Align top flange of chamber to rotation axis for position and perpendicularity - use dial indicator - adjustment screws for tilt, radial Access hole for vertical pusher screw Lateral pusher screw Align this flange to rotation axis

Chamber Assembly (c) Vertical rotation Alignment (5) Tighten bolts on bottom alignment plate (6) Raise lower support bearing (still allows chamber rotation) -- swivel self-aligning bearing; 30,000 lb. capacity -- leveling pad vertical adjustment -- plan for 1 mm vertical rise (chamber fiducialization) -- takes weight off cam bearings / six strut support assembly (7) Phase I: Clamp chamber to base plate (no rotation) -- keep lifted off cam bearings Tighten bolts Raise feet by 1mm

Chamber Port Accuracy CMM report Goal: Top chamber flange to rotate with <10 micron axis of confusion (1) Top port alignment to bottom flange -- center offset: dx=0.0067” dy=0.0142”, dr=0.0157” -- parallelism: dz = ” dA = 0.6 millirad (2) Intersection of analyzer flange to vertical axis: dz = ” (from design value of 9.0” below top flange) -- not crucial: align beam to analyzer + sample to beam dy = ” (crucial for polar rotation) analyzer

Seismic Parameters Center of gravity Wgt = 3350 lbs. Height = 25.5” Base Floor Bolting Pattern 60” (1)Floor survey 3 existing 1/2” HILTI (type HDI) shells do not affect new anchor locations No grade beam conflicts (2)Add four new 1/2” HILTI (type HDI) expansion anchors on 48”x44”. (3)Factor of safety ~1.4 (w/o vacuum load) ~1.3 (vacuum load) Weldment: ” Analyzer ” Off-axis 32” est. IP: ” Off-axis 20” Manipulator/Centiax ” Rotary Seal ” 47” ” Struts: ” Pumping Tree: ” Chamber: ” 48” 52” X

Seismic Safety Center of Gravity 3700 lbs at 28.6” from floor (2.38” towards analyzer) Floor Anchoring —use new ½” HILTI HDI on 48” x 44” Allowable loads: Tension: 2,374 lbs. / Shear: 1,798 lbs. — min. lever distance from bolt to edge = 46” Horizontal inertial load in earthquake as high as 0.7 g acceleration x 3700 lbs. = 2580 lbs. Tension load due to overturning: worst case leverage ratio = 25” / 21.8” =.62 pull-out load on two anchors = 2580x.62 = 1600 lbs. pull-out load (tension) per anchor = 1600 / 2 = 800 lbs. Shear load due to sliding: shear load per anchor = 2580 / 4 = 640 lbs. Safety Factor = 1/( (800/2374) + (640/1798) ) = 1.4 If 500 lbs of vacuum load added (equiv. 450 lbs towards analyzer, 210 lbs perp. analyzer) Safety Factor = 1 / ( (3030*.57/2/2374) + (3030/4/1798)) = 1.3 (Following Engineering note AL0015)

Top Rotary Seal (Phase I) Standard 2-part face seal (have in hand) -- APX design --> LBNL --> DV Manufacturing (fab) H=1.81” -- double-sided flange on bottom for clearance of top ports standard: H=0.87” -- double-sided flange on top to match Phase II height custom: H=1.8535” (or 2 x 0.87” = 1.74”?) Sum = 4.53” (Phase II) -- Custom 3-part radial seal: H = ” -- bottom connects to rotatable chamber (analyzer polar angle) -- middle connects to fixed stand -- top connects to rotatable manipulator (sample polar angle) Phase I vs Phase II

Analyzer Rotation (Phase I) -- rigid nipple -- analyzer in horizontal geometry (vertical slit) -- support bracket off of base plate -- increase rigidity to stand (Phase II) -- Custom high load 2-part radial seal -- Rotation for selection two orientations (not scanning) -- Slow rotation speed (factor for safety) -- Sliding contact of analyzer lens mu-metal with chamber mu-metal (?) Phase I vs Phase II

Summary Phase 1 (Sept. install): Fixed chamber and analyzer Turntable installed but locked down Assembly will require extensive alignment Vertical load taken by spherical bearing Phase 2 Need robotics safety review/plan for motions Vacuum load preloads cam bearings Seismic loading has a factor of safety of 1.27 min. Redesign of analyzer mu-metal liner may be needed