Mechanical Engineering Design Review

BL 4.0.3 ARPES Endstation

Derek Yegian, Jonathan Denlinger, Keith Franck4/18/2008

Beamline 3D Layout

M302

Entrance slit

Monochromator

M303 G301 G302

G302 (temp)

Exit slit

M321/M331

M332 M333

M322 M323

RIXS

ARPESTOF

Gas Cell

Endstation Layout

M332 M333

M322 M323

RIXS

ARPES

TOF (2-bunch only)

44”

ARPES – Phase 1 (Sept. Installation)

Fixed Spool

Sample rotation2-part rotary

AnalyzerFixed, horizontal

TurntableLocked 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 AccuracyCMM 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 = 24.375” dA = 0.6 millirad

(2) Intersection of analyzer flange to vertical axis: dz = -0.0185” (from design value of 9.0” below top flange)

-- not crucial: align beam to analyzer + sample to beamdy = -0.0076” (crucial for polar rotation)

analyzer

analyzer

Seismic Parameters

• Center of gravity

Wgt = 3350 lbs. Height = 25.5”

• Base Floor Bolting Pattern

60”

(1) Floor survey3 existing 1/2” HILTI (type HDI) shells do

not affect new anchor locationsNo 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: 1350 lbs @ 6.35”

Analyzer325 lbs @ 58”Off-axis 32” est.

IP: 250 lbs @ 17.1”Off-axis 20”

Manipulator/Centiax75 lbs @ 83.8”

Rotary Seal40 lbs @ 71.9”

47”

450 lbs @ 36.5”

Struts: 150 lbs @ 26”Pumping Tree: 450 lbs @ 27”

Chamber: 400 lbs @ 51.3”

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 = 4.53375”-- 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 2Need 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