PEP-II IR2 LER BPM PEP-II IR2 LER BPM Button Pulling Mechanism Button Pulling Mechanism October 25, 2006 October 25, 2006 Nadine Kurita, Michael Kosovsky, and Nick Nadine Kurita, Michael Kosovsky, and Nick Reeck Reeck
Jan 01, 2016
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