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Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator Research Program

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Page 1: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

Summary of Accelerator Systems Collimation Parallel Session

19 October 2007

LARP CM#9 - SLAC

Tom Markiewicz/SLAC

BNL - FNAL- LBNL - SLAC

US LHC Accelerator Research Program

Page 2: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 2 / 8

CRYSTAL COLLIMATION EXPERIMENTAT THE TEVATRON

Nikolai MokhovFermilab

Mission Statement

We propose an experiment at Fermilab’s Tevatron to measure the predicted improvement in collimation efficiency that could be obtained by replacing amorphous primary collimators with bent crystals.

Considering the unique possibility provided by the Tevatron Collider, and having already established fruitful collaborative efforts on crystal characterization, tests and use for collimation, we propose to test and confirm models of multi-turn dynamics with crystals by exploiting channeling and newly understood phenomena such as volume reflection as well as to further study collimation.

Page 3: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 3 / 8

2005 Tevatron Experiment

(Analysis by V. Shiltsev)(Analysis by V. Shiltsev)

Channeled beam“peak” width is22±4 rad (rms)

With E03H out,LE033C BLM isproportional tonuclear interact.rate in crystal

Page 4: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 4 / 8

2006 Installation of Shorter Crystal with Smaller Bend and 2007 Run/Analysis

Original installation had misaligned crystal

Angular reproducibility for a horizontal translation of the table terrible– 1 mil horizontal translation can produce an angle error of 100urad

Building a new goniometer with new specifications for motion tolerance and vacuum is needed

2 urad scan of channel May 26,2007

700

800

900

1000

1100

1200

1300

-2100 -2000 -1900 -1800 -1700 -1600 -1500 -1400 -1300 -1200

laser angle (urad)

loss

(h

z/vo

lts)

t:le033c t:le0pin 50 per. Mov. Avg. (t:le0pin) 24 per. Mov. Avg. (t:le033c)

150urad

320 urad

channelInto the beam

Angularmotion

Page 5: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 5 / 8

Other Issues with 2007 Run

Noisy Losses on Detectors:Noisy losses produced on the PIN and BLM monitors look like channeling

signatures. These are real effects caused by motion of the beam, effects of abort gap

cleaning, etc.Solutions to these are refining operational procedures and attempting to build

better orbit stabilization software around the area of the bent crystal.

Improving Beam Diagnostic Capabilities– Current beam diagnostics used to detect channeled and VR beam is a PIN

diode system and a Tevatron ionization style BLM. (picture in next slide)– The PIN diode is reasonable for detecting the rate of nuclear interactions

at the crystal.– In order to view the channeled and VR beam downstream of the crystal

better diagnostics are needed. Roman Pot style detectors have been considered and offered.

Noise on BLM signals

Page 6: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 6 / 8

How to Meet Mission Goals?

Demonstrate high efficiency volume reflection seen in RD22 extraction line experiment in collider environment using EDGE of crystal

Page 7: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 7 / 8

Plans for FY 2008: 3 Choices

Beam Studies: Nothing new, keep playing aroundContinue to use the installed crystal assembly and strip crystal to

demonstrate main goals.This may require more study time due to increased setup now that problems

with goniometer have been characterized.Would like to have 2 to 3 of End of Store study periods as early as Dec. 2007

to demonstrate well characterized channeling from the strip crystal now that more is understood about the goniometer motion.

New Goniometer(s): No new diagnostics, but replace goniometerStart specifications and engineering for new horizontal goniometer that would

replace current assembly.Currently have identified a FNAL engineer to work on this.If full 2 plane crystal collimation is going to be demonstrated that would

require an additional vertical goniometer to be built.A full simulation would be required for best placement of the vertical

goniometer as well locations of channeled and volume reflected beams.Beam Diagnostics: The whole enchilada: Raison d’etre for

collaborationStart specifications and assessing new or additional beam diagnostics that will

be needed.

Page 8: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 8 / 8

Tevatron Warm Space for New Hardware

antiprotons

E0

target

IR

proton s

D0

A0

collimator

IR

B0

C0

F0

Proton Set 1D49 Tar, E03 & F172 2nd Proton Set 2D171Tar, D173 & A0 Pbar Set 1F49 Tar, F48 & D172Pbar Set 2F173 Tar, F171 & E02

F171 collimator

E01 collimator E02 collimator

All these devices will have to be removedto accommodate space for new hardware

These locations have additional warm space but may not be optimal.

Page 9: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 9 / 8

Time

Timing for Installing New Hardware:

Should be stressed that any new hardware installed into the Tevatron for use in 2009 will have to be ready for the Summer 2008 shutdown.

Ferrara needs 6 months minimum to fabricate goniometers and will not spend $/effort without FIRM COMMITMENT to run the experiment

Page 10: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 10 / 8

COLLABORATION, LOI AND MEETING ON DEC. 6-7

Very encouraging support from• LARP management• Fermilab management• CERN management• INFN management• August Accelerator Advisory Committee at

Fermilab

It was proposed that we prepare a Letter-of-Intent (LOI), “Crystal Collimation Experiment at the Tevatron” and form an official collaboration.

Page 11: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 11 / 8

Immediate Requirement

Need full realistic multi-turn simulations – for the current lattice and crystal/collimator configuration to confirm 1999-2003 results, justify a choice of a short crystal and identify locations for comprehensive beam diagnostics (single particle tracking capability?) and second (vertical) crystal/goniometer

Can this happen in time for Dec 6-7 Collaboration Meeting in sufficient detail to motivate invasive hardware installation, diagnostic construction and formation of a 50-100 member international collaboration?

1) Nikolai & Sasha Drozhdin committed

2) Known to be needed in April 2007, but zero produced

Page 12: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 12 / 8

Rotatable CollimatorsJeff Smith

beambeam

Page 13: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 13 / 8

Design of Jaw-Shaft-Mandrel

Cu coolant supply tubes twist to allow jaw rotation

Hub area

Glidcop Cu Mo

Cantilever Mo shaft @ both ends

Helical cooling channels

25mm below surface

20 facets

Page 14: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 14 / 8

Design of Jaw Support and Rotation Mechanism

Triple CogGeneva DriveWheel required for 512 clicks per facet

U-Joint Flexes forShaft “sag” and “Slewing”

Water Cooling Inlet and outlet

Page 15: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 15 / 8

Design Complete Except for RF Features

Jaw

Geneva Mechanism

Support Bearings

Worm GearShaft

Water CoolingChannel

U-Joint Axle

1-2mm Gap

Diaphragm

Page 16: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 16 / 8

Current Vision of RF Transitions

Spiral style backing springs reside inside“Sheath” (sheath not shown)

Thin sheet metal RF “Curtain”

Round to Square TransitionTransition “Socket”

Spherical profile “Fingers”

Page 17: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 17 / 8

Up Beam end detail view away from beam side

Spring flexes to maintain contact force on “Fingers” for longitudinal and lateral displacements of the Jaw ends

2 cam buttons (not shown) lift “Socket” off “Fingers” during Jaw rotation and rest in detents during collimation

Jaw cooling return line

Page 18: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 18 / 8

Page 19: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 19 / 8

Braze Test#2 Delivered 19 Dec 2006

Page 20: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 20 / 8

Vacuum Bake of Braze Test#2 Results: 4/1/07~3x over LHC Spec

1st Jaw Braze Test Assembly has been vacuum baked at 300 degrees C for 32 hours.

•LHC Requirement = 1E-7 Pa = 7.5E-10 Torr•Baseline pressure of Vacuum Test Chamber:

4.3E-7 Pa (3.2E-9 Torr)•Pressure w/ 200mm Jaw Assy. in Test Chamber: 4.9E-7 Pa (3.7E-9 Torr)•Presumed pressure of 200mm lg. Jaw Assy.:

6.0E-8 Pa (4.5E-10 Torr)•Note: above readings were from gauges in the foreline, closer to the pump than to the Test Chamber. Pressures at the part could be higher.

Outcome:SLAC vacuum group has suggested longitudinal grooves be incorporated into the inner length of jaws; incorporated into next prototype

Page 21: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 21 / 8

6/25/07-7/2/07 Slice & Dice Braze Test#2

∙ Evidence of fracturing along grain boundaries presumed due to too-rapid cooldown after braze - areas near ends and OD look better∙ Braze of jaws to hub GOOD∙ 3 of 4 jaw-jaw brazes GOOD

Interior slice: polished & etched

∙ Same fracturing patterns as in other slice∙ Braze of cooling coils to jaw ID good∙ Braze of cooling coil bottom to mandrel so-so

Longitudinal slice

Page 22: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 22 / 8

Braze Test #3: Vacuum tests

•3rd Jaw Braze Test Assembly has been vacuum baked at 300 degrees C for 32 hours. Results in slightly lower pressure.•Inclusion of longitudinal grooves in the inner length of jaws for better outgasing•Test Chamber setup similar to previous test.

Old New

Baseline 3.2E-9 Torr 2.4E-9 Torr??

w/ jaw assy. 3.7E-9 Torr 3.4E-9 Torr

Presumed jaw assy. pressure

4.5E-10 Torr 10E-10 Torr??

LHC requirement

7.5E-10 Torr 7.5E-10 Torr

Page 23: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 23 / 8

Braze Test #3: Sectioning & ExaminationCu grain boundary cracking during brazing

Specimen 140mm OD x 60mm ID x 200mm L (¼ section shown)

- one braze cycle in the 900 C range- grain boundary cracks located in interior regions- believed due to excessive heating rate- Glidcop to be testedConcerns- Effect on performance- What happens in accident case?

Page 24: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 24 / 8

Glidcop Al-15 Heat sampleWhile 1st jaw used to test thermal mechanical issues is

Copper, first full 2 jaw prototype will use Glidcop

2 Heats (at Jaw brazing temperature)

No grain boundary cracking is apparent Metallographic samples are being prepared for microscopic

inspection

Page 25: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 25 / 8

Apr 6: Cu-Mo Hub Braze Test Assembly after 3 additional heat cycles (to mimic full assembly procedure) then

sectioned. Cu “finger” fractured

Small holes held braze wire

•Grain boundary issues?•Possible fracturing?

Cu-Mo joints we care about

1mm expansion gap

Samples sliced & polished and sent to Physical Electronics lab for analysis 4/23:Fractures evident

Page 26: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 26 / 8

Compression fit for Cu-Mo joint

• Another option is to use a compression fit and diffusion bonding.

Copper Jaw is constrained on the outside diameter with Carbon and when heated to ~ 900 degrees C is forced to yield so that upon cooling to ~ 500 degrees C the inner diameter begins to shrink onto the Mo Shaft resulting a substantial interference fit.

Test hub fell apart once we made a slice!

Page 27: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 27 / 8

Cu-Mo joint: Segmented Moly for expansion

• Another option is to use a segmented flexible molybdenum end to prevent fractures and prevent Co from pulling away from Moly.

Will be cutting small samples for metallurgy tests. May make slight modifications for better braze joint

Page 28: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 28 / 8

Molybdenum Half Shafts & Copper Hub Halves braze preparations

Expander PlugRetainer Ring

Page 29: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 29 / 8

21 Mar 2007: Full length Mandrel: In-House & Inspected

– Now that shaft design complete, order to bore central hole made– Will wind with in-house copper tubing

Page 30: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 30 / 8

Fixture for stacking 16 24cm-long quarter round jaws on full 960mm

cooling coil wrapped mandrel(mostly catalog parts: ordered)

Page 31: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 31 / 8

Up Beam Flex Mount Assembly showing Ratchet and Actuator

Page 32: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 32 / 8

Up Beam Flex Mount Assembly showing Ratchet and Actuator

Page 33: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 33 / 8

Agreement in Progress to Buy a damaged “TCS1” collimator and stand from CERN

Page 34: Summary of Accelerator Systems Collimation Parallel Session 19 October 2007 LARP CM#9 - SLAC Tom Markiewicz/SLAC BNL - FNAL- LBNL - SLAC US LHC Accelerator

LARP CM9 - 19 October 2007 Collimation Summary - T. MarkiewiczSlide n° 34 / 8

LARP Collimator Delivery Schedule

Done Braze test #1 (short piece) & coil winding procedures/hardware

Prep heaters, chillers, measurement sensors & fixtures, DAQ & lab

Section Braze test #2 (200mm Cu) and examine –apply lessons

Braze test #3 (200mm Cu) – apply lessons learned

Fab/braze 930mm shaft, mandrel, coil & jaw pieces

2008-01-01 1st full length jaw ready for thermal tests

Fab 4 shaft supports with bearings & rotation mechanism

Fab 2nd 930mm jaw as above with final materials (Glidcop) and equip with rf features, cooling features, motors, etc.

Modify 1st jaw or fab a 3rd jaw identical to 2nd jaw, as above

Mount 2 jaws in vacuum vessel with external alignment features

2008-09-01 2 full length jaws with full motion control in vacuum tank available for mechanical & vacuum tests in all orientations (“RC1”)

Modify RC1 as required to meet requirements

2009-01-01 Final prototype (“RC2”) fully operational with final materials, LHC control system-compatible, prototype shipped to CERN to beam test