PEP-II IR2 LER BPM Button PEP-II IR2 LER BPM Button Pulling Mechanism Pulling Mechanism PEP-II IR2 LER BPM Button PEP-II IR2 LER BPM Button Pulling Mechanism Pulling Mechanism

October 25, 2006October 25, 2006

Nadine Kurita, Michael Kosovsky, and Nick ReeckNadine Kurita, Michael Kosovsky, and Nick Reeck

October 25, 2006October 25, 2006

Nadine Kurita, Michael Kosovsky, and Nick ReeckNadine Kurita, Michael Kosovsky, and Nick Reeck

PEP-II Vacuum p2

MotivationMotivation

Low Energy Ring (LER) Beam Position Monitor Low Energy Ring (LER) Beam Position Monitor (BPM) feedthroughs are experiencing button (BPM) feedthroughs are experiencing button heatingheating

Button

PEP-II Vacuum p3

Motivation, Cont’dMotivation, Cont’d

BPM feedthroughs cannot BPM feedthroughs cannot easily be replaced, as they easily be replaced, as they are welded into the are welded into the chamberschambers

To replace, every chamber would need to be removed. Then each feedthrough would need to be:

Ground off the chamber

Replaced with a new BPM feedthrough

Electron beam welded into chamber

CostCost and and timetime prohibitive; prohibitive; need an alternate solutionneed an alternate solution

Weld

PEP-II Vacuum p4

PurposePurpose The purpose of the button puller is to remove the The purpose of the button puller is to remove the

BPM buttons from the existing vacuum chambers BPM buttons from the existing vacuum chambers without removing the chambers (in situ).without removing the chambers (in situ).

Remaining 2.4 mm pin functions as new “button”

BPM

CHAMBER

PEP-II Vacuum p5

AccessAccess

Nearly every BPM Nearly every BPM chamber has a chamber has a bellows on at least bellows on at least one end of the one end of the chamber.chamber.

The bellows can be The bellows can be removed to give removed to give chamber access.chamber access.

Bellows

BPM Location

PEP-II Vacuum p6

AccessAccess

There is There is approximately 4” approximately 4” (101.6 mm) between (101.6 mm) between the chambers the chambers available for the available for the mechanism to be mechanism to be inserted into the inserted into the chamber when the chamber when the bellows is removed. bellows is removed.

~4” Gap

PEP-II Vacuum p7

Assembly SequenceAssembly Sequence

Locking Screw

Shafts

Collet

Anchor

BorescopeHandles

PEP-II Vacuum p8

How It WorksHow It Works

The The colletcollet is carefully positioned below the button is carefully positioned below the button The borescope is used to guide the collet into position

Collet

Button

PEP-II Vacuum p9

How It Works, Cont’dHow It Works, Cont’d

With the With the colletcollet in position, the cam shaft is activated by rotating the in position, the cam shaft is activated by rotating the cam handlecam handle..

Cam Handle

How It Works, Cont’dHow It Works, Cont’d

Cam Shaft

The The cam shaftcam shaft transforms the rotational motion into translational transforms the rotational motion into translational motion.motion.

The cam shaft consists of two cams that are lagging 90 deg to each other. The inner cam operates the Collet; the outer cam operates the Outer Plunger, PF-343-650-14.

Outer Plunger

Collet

Collet CamOuter Plunger Cam

PEP-II Vacuum p11

Lab TestingLab Testing Prior to use in the tunnel, we verified operation in Prior to use in the tunnel, we verified operation in

the lab.the lab. Worked exactly as intended Did not break a single pin in 10+ button pulls

Inserting puller into the chamber Borescope Image

PEP-II Vacuum p12

In the TunnelIn the Tunnel

BPM distance from the end of the chamber varies BPM distance from the end of the chamber varies from 3” to 72”.from 3” to 72”.

Alignment with button tricky, often time-Alignment with button tricky, often time-consumingconsuming

CHAMBER

BPM

3” to 72”

PEP-II Vacuum p13

Pin BreakagePin Breakage On average, one pin in every 4 feedthroughs is broken. On average, one pin in every 4 feedthroughs is broken.

Fractures may occur due to:Fractures may occur due to: Pre-existing cracks in the pin (brittle fracture) Slight misalignment of button puller “Cold welding” of the button to the pin

In every case, fracture occurs at diameter change in pin (the In every case, fracture occurs at diameter change in pin (the logical fracture site)logical fracture site)

Pin Fracture Site

PEP-II Vacuum p14

ProgressProgress

GREENGREEN = Completed location = Completed location REDRED = Yet to be pulled = Yet to be pulled As of Monday, October 23:As of Monday, October 23:

97 out of 117 buttons pulled (83%) 26 out of 97 buttons pulled broke the pin (27%)

LER

IP

Arc 3 Arc 1

11

62

20

22

20

32

20

52

20

82

20

62

20

56

20

92

21

12

21

22

21

42

21

52

21

64

21

72

21

82

21

85

30

62

30

41

30

42

30

52

30

72

30

82

31

02

31

12

31

32

31

42

31

49

31

62

31

72

31

82

31

84

PEP-II Vacuum p15

PEP-II LER Arc BPM PEP-II LER Arc BPM ReplacementReplacementPEP-II LER Arc BPM PEP-II LER Arc BPM ReplacementReplacement

PEP-II BPM Retrofit UpdatePEP-II BPM Retrofit UpdateOctober 25, 2006October 25, 2006

Nick Reeck & Nadine KuritaNick Reeck & Nadine Kurita

PEP-II BPM Retrofit UpdatePEP-II BPM Retrofit UpdateOctober 25, 2006October 25, 2006

Nick Reeck & Nadine KuritaNick Reeck & Nadine Kurita

PEP-II Vacuum p16

Existing LER Arc BPM FeedthroughExisting LER Arc BPM Feedthrough

Pin

15mm Button

Ceramic Disc(or “Glass”)

Housing

SMA Jack

Cross section of existing BPM (SA-342-601-26) with parts labeled

PEP-II Vacuum p17

Option 1: Pull Button, Leave PinOption 1: Pull Button, Leave Pin

Pull off 15mm button, leave the pin as a 1.4mm Pull off 15mm button, leave the pin as a 1.4mm “button”“button”

Pros:Pros: Simple

Cheap

Cons:Cons: May lose some

resolution, especially in single bunch, single pass

PEP-II Vacuum p18

Option 2: Press FitOption 2: Press Fit Pull off 15mm button, press on a 7mm buttonPull off 15mm button, press on a 7mm button

Pros:Pros: “On Site” modification

(slight radioactivity a concern)

Good electrical contact

More robust that old buttons

Cons:Cons: Button press largely “trial

and error”, have to measure buttons and pins to .0001”

Lots of SLAC labor

PEP-II Vacuum p19

New BPM FeedthroughNew BPM Feedthrough

Remove old BPM feedthrough, install new BPM Remove old BPM feedthrough, install new BPM feedthroughfeedthrough

Pros:Pros: Better thermal

conductivity (Boron Nitride disc)

Very robust

Excellent electrical contact

Less SLAC labor

Cons:Cons: More expensive

PEP-II Vacuum p20

New BPM DesignNew BPM Design

One-Piece Button and Pin

Laser Welds

Borosilicate Glass

Boron Nitride Disc

PEP-II Vacuum p21

Photos of New DesignPhotos of New Design

PEP-II Vacuum p22

Electropolishing the MolyElectropolishing the Moly Purpose: Smooth surface cracks to reduce stress Purpose: Smooth surface cracks to reduce stress

concentration pointsconcentration points We wish to reduce or eliminate the failure mode seen in IR-2 BPM

feedthroughs As can be seen in these photos, electropolishing is effective

Before 1 Minute 3 Minutes

PEP-II Vacuum p23

Electropolish FixtureElectropolish Fixture

Made a fixture to hold the parts during Made a fixture to hold the parts during electropolish (~700 parts electropolished to date).electropolish (~700 parts electropolished to date).

Prevents pins from being electropolished; rough surface likely helps glass adhesion during firing

Molybdenum Button / Pins

Electropolish Fixture

PEP-II Vacuum p24

BakeoutBakeout

First 44 BPM feedthroughs were placed in a can First 44 BPM feedthroughs were placed in a can for bakeout for bakeout

Vac shop could not get the can to pump down

XPS Results – marginally clean parts, but high vapor pressure contaminants

Magnesium, sodium, calcium, sillicate, carbon

Add up to 36 atomic percent of surface composition

BPM feedthroughs were cleaned at SLAC BPM feedthroughs were cleaned at SLAC (degreased), put back in can for bakeout on (degreased), put back in can for bakeout on Thursday, October 19Thursday, October 19

Still somewhat dirty, having trouble pumping down

As of Monday, October 23 we do not have RGA data

PEP-II Vacuum p25

Installation Schedule (estimate)Installation Schedule (estimate)

IP

Arc 1

11/3 – 11/10

Arc 3

11/10 – 11/17

Arc 5

11/17 – 11/24

Arc 7

11/24 – 12/1

Arc 9

12/1 – 12/7

Arc 11

12/7 – 12/14

(Assumes 2 crews, 2 weeks to complete each arc)

PEP-II Vacuum p26

Questions?Questions?

PEP-II Vacuum p27

Phases of OperationPhases of Operation Once the collet is in position, there are four phases during one Once the collet is in position, there are four phases during one

shaft handle rotation.shaft handle rotation. One complete shaft rotation is necessary to pull the buttonOne complete shaft rotation is necessary to pull the button

PEP-II Vacuum p28

Phase 1Phase 1 0-90 degrees: The Collet is being inserted into the .04” radial gap and

engaged with the BPM button. The Outer Plunger is dwelling.

Collet

Outer Plunger

PEP-II Vacuum p29

Phase 2Phase 2 90-180 degrees: The Collet is dwelling in the inserted position. The Outer Plunger

is moving upward to force the collet fingers tightly around the button.

PEP-II Vacuum p30

Phase 3Phase 3

180-225 degrees: The Collet, with the engaged BPM Button, travels a half stroke (4mm) downward. Hence, the BPM button is being removed (pulled from the BPM pin). The Outer Plunger is dwelling in the upward position, preventing the Collet from disengaging from the BPM button.

PEP-II Vacuum p31

Phase 3, cont’dPhase 3, cont’d

225-270 degrees: The Collet, with the engaged BPM Button, travels the rest of the stroke (4mm) toward chamber center plane. The Outer Plunger is dwelling in the inserted position.

PEP-II Vacuum p32

Phase 4Phase 4

270-360 degrees: The Collet, with the removed BPM Button, is dwelling in the lower position. The Outer Plunger is moving towards the chamber center plane to its lower position.

So, one 360 degree rotation of the shaft handle removes one BPM button.

PEP-II Vacuum p33

The mechanism is then disassembled. The BPM The mechanism is then disassembled. The BPM button and the mechanism are removed from the button and the mechanism are removed from the chamber.chamber.

DisassemblyDisassembly

PEP-II Vacuum p34

To remove the next BPM Button the cycle is repeated. To remove the next BPM Button the cycle is repeated. The mechanism is rotated 180 degrees about the vertical axis to

remove the right versus the left BPM buttons

The mechanism is rotated 180 degrees about the horizontal axis to remove the top versus the bottom BPM buttons.

Mechanical Design (cont.)Mechanical Design (cont.)

Top Left Top Right

Bottom Left Bottom Right

(Looking Into Chamber)

PEP-II Vacuum p35

BPM Pull StatusBPM Pull StatusLeak checked

23-Oct-06 14:00 PulledStarted or triedNot started

IR2 BPM status 31 Total units24 Done

7 To doNeeds

No. No. No. Modifedunit buttons pulled broken broken where color puller comments1162 2 no wait until arc 1 vents2022 4 4 1 top wall blue top aisle splayed2032 4 4 2 top, bot aisle red, green bot wall dark2052 3 3 1 top aisle red, green2056 3 3 3 not top wall all but blue2062 1 1 02082 4 4 1 bot aisle green2092 4 4 02112 4 4 02122 4 4 2 bot wall, bot aisle yellow, green2142 4 4 02152 4 4 1 top wall blue2164 4 2 yes 8 mm mask in the way2172 4 4 2 top wall, top aisle blue, red2182 4 yes 3 mm bot mask in the way2185 4 4 1 top wall blue2203

IPIP30243041 4 2 1 top aisle red yes 15 mm msk nearby on bot3042 4 4 0 3052 4 2 1 bottom wall yellow yes 11 mm mask close by3062 4 4 1 top wall blue3072 4 4 1 bottom wall yellow broken pin has splayed prongs3082 4 4 2 top wall, bot aisle blue, green3102 4 yes Bottom screen problem3112 4 4 0 next to 3 mm mask3132 4 4 1 bot aisle green3142 4 yes Vertical bend stops puller3149 4 4 03162 4 4 0 3172 4 4 2 top wall, top aisle blue, red next to 3 mm mask3182 4 4 1 bottom wall yellow 3184 4 4 2 top wall, bot wall blue, yellow 3192?

PEP-II Vacuum p36

Installation ScheduleInstallation Schedule

DeliveredDelivered October 11 – 45 units

October 20 – 150 units (195 total)

To Be DeliveredTo Be Delivered October 27 – 150 units (345 total)

November 8 – 150 units (495 total)

November 15 – 150 units (645 total)

November 22 – 150 units (795 total)

November 29 – 105 units (900 total)

PEP-II Vacuum p37

XPS ResultsXPS Results