# Presentation: 239030

## The LARP Collimation Program

- 13 June 2006
- LARP DOE Review - Fermilab
- Tom Markiewicz/SLAC

*BNL - FNAL- LBNL - SLAC*

_**US LHC Accelerator Research Program**_

## LHC Collimation Requirements

- LHC Beam Parameters for nominal *L*=1E34cm-2s-1:
- 2808 bunches, 1.15E11 p/bunch, 7 TeV  350 MJ
-  t=25ns,  ~200m (collisions)
- System Design Requirement: Protect against quenches as beam is lost
- Design shielding for expected <>~30hr or 3E9 p/s or 3.4kW
- Design collimator cooling for = 1 hour or 8E10 p/s or 90kW
- Plan for occasional bursts of = 12 min or 4E11 p/s or 450kW
- abort if lasts > 10 sec
- Collimation system inefficiency:
-  Inefficiency ∙ Max Loss Rate < Quench Loss Rate
- dQ/dV ~ 1.5mW/gm in SC coil causes quench
- Estimate inefficiency of collimation system via SIXTRACK program
- Determine minimum required inefficiency via FLUKA/MARS
- 8E6 p/s on TC will quench Q3 in triplet  2E-5 inefficiency @ 4E11 p/s loss

## Betatron Collimation in IR7
3 short (60cm) “Primary” collimators (H,V,S) at 6
11 long (1m) “Secondary” Collimators (various angles) at 7
Momentum Collimation in IR3
4 long (1m) “Secondary” collimators
Other
1m H&V Copper Tertiary Collimators at Experimental IRs at 8.4
1m Cu or W Absorbers at 10
Warm Magnets, tunnel and shielding absorb remainder of lost beam energy

Non-Accident Engineering Challenge
The first long secondary collimator downstream of the primary system must absorb much more energy than any other secondary in the system since 80-85% of list particles interact inelastically in the 6 primaries
The deformation specification of the collimator jaw is set at 25m in order to maintain system efficiency

- 3 short (60cm) “Primary” collimators (H,V,S) at 6
- 11 long (1m) “Secondary” Collimators (various angles) at 7
- Momentum Collimation in IR3
- 4 long (1m) “Secondary” collimators
- Other
- 1m H&V Copper Tertiary Collimators at Experimental IRs at 8.4
- 1m Cu or W Absorbers at 10
- Warm Magnets, tunnel and shielding absorb remainder of lost beam energy
- Non-Accident Engineering Challenge
- The first long secondary collimator downstream of the primary system must absorb much more energy than any other secondary in the system since 80-85% of list particles interact inelastically in the 6 primaries
- The deformation specification of the collimator jaw is set at 25m in order to maintain system efficiency

**The LHC Collimation System**

**Accident Scenario**
-  When beam abort system fires asynchronously with respect to abort gap (armed HV trips accidentally) **8 full intensity bunches 1 MJ** will impact collimator jaws

## Phase I and Phase II Collimation

- Phase I: Use Carbon-Carbon composite as jaw material
- 60cm/1m Carbon undamaged in Asynchronous Beam Abort
- Low energy absorption of secondary debris eases cooling & tolerances
- 6-7 kW in first 1m C secondary behind of primaries when dE/dt=90 kW
- 10 sec 450 kW load handled as a transient
- Low, but adequate collimation efficiency to protect against quenches at lower *L *expected at startup
- High, but adequate machine impedance for stable operation at low *L *expected at startup
- Phase II: Metal collimators into vacant slots behind each Phase I secondary
- Good impedance and efficiency allowing LHC to reach design L= 1E34
- After stable store open Carbon jaws and close Metal jaws
- Jaw will be damaged: what to do?
- More energy from primaries will be absorbed: cooling & deformation
- only pertains to one unlucky collimator per beam!

## IR7 Collimator Layout 11 Carbon Phase I and 11 Metal Phase II Secondary Collimators per beam in IR7

## Impedance Limits LuminosityCarbon Collimators Dominate Impedance

**Impedance Limits Luminosity****Carbon Collimators Dominate Impedance**

**Stable**

**Unstable**

## Study of Material for Secondary Collimators

- Copper

- Similar result was obtained by Ralph Amann

- Yunhai Cai

**Study of Material for Secondary Collimators**

-      High Z materials improve system efficiency
- Copper being considered because its high thermal conductivity
-      Available length for jaws is about 1 meter
-      Achievable efficiency is about 3.5x10-4 at 10 
- As Sixtrack program adds absorbers/tertiary collimator we expect ~x10 improvement

- Carbon

## Four LARP Collimation Program Tasks:Address Efficiency, Reliability and Design of Phase I & Propose a possible solution for Phase II

- Use RHIC data to benchmark the code used to predict the cleaning efficiency of the LHC collimation system and develop and test algorithms for setting collimator gaps that can be applied at the LHC
- Responsible: Angelika Drees, BNL [Task #2]
- Understand and improve the design of the tertiary collimation system that protects the LHC final focusing magnets and experiments
- Responsible: Nikolai Mokhov, FNAL [Task #3]
- Study, design, prototype and test collimators that can be dropped into 32 reserved lattice locations as a part of the “Phase II Collimation Upgrade” required if the LHC is to reach its nominal 1E34 luminosity
- Responsible: Tom Markiewicz, SLAC [Task #1]
- Use the facilities and expertise available at BNL and FNAL to irradiate and then  measure the properties of the materials that will be used for phase 1 and phase 2 collimator jaws [proposed new work package]
- Responsable: Nick Simos, BNL [Task #4]

## Task 2: Use RHIC Data to Benchmark LHC Tracking Codes

- Scope:
- Install SixTrackwColl particle tracking code at BNL and configure it to simulate RHIC performance for both ions and protons.
- Take systematic proton and ion data and compare observed beam loss with predictions
- Test (and perhaps help to develop) algorithms proposed for the automatic set up of a large number of collimators
- Resources Required:
- 50% postdoc/student + supervision + travel
- Timescale:
- Now until LHC beam commissioning
- Comments
- Preliminary data taken; comparison programs being improved
- Postdoc search ongoing

## Task 2: Progress Since June 2005 DOE Review

- State of affairs June 2005: Ion loss maps in RHIC agree with tracking results, protons do not.
- Since then, no progress : analysis of proton loss data awaiting manpower
- hope is that CERN student who set up Sixtrack with BNL lattice will take BNL postdoc job
- New work on Collimator efficiency & set up
- Heavy Ions and protons very different
- positioning procedure for p is slow and tedious and not reproducible
- For protons, the effectiveness of the individual collimators changes from store to store and between the IRs
- Other LARP (not collimation) activities:
- LBL luminosity monitor  installed in RHIC IR10 between existing luminosity detectors for calibration later this year
- E-cloud studies with LHC style electron detectors installed in IR10

- Electron Detector in RHIC

## RHIC Tracking Results

- Ions Agree
- With
- “ICOSIM”

- Protons Data does not agree

## Task 3: Model tertiary collimators at the LHC experimental insertions

- Scope:
- CERN FLUKA team occupied with collimation system performance throughout ring and need help understanding beam loss & backgrounds at the EXPERIMENTAL AREAS
- MARS team at Fermilab experienced & well equipped
- Resources Required:
- 25% postdoc + supervision + travel
- Timescale:
- Now until LHC beam commissioning
- Status
- Initial results promising; More detailed simulations planned
- Determine Efficiency of TCT and Relative performance of W vs. Cu
- Engineering Studies, Accident Studies, More realistic Halo, Sensitivity studies
- Once 3 more files of input data become available, task can be completed within 6 months and closed down

## June 2005 StatusModeling tertiary collimators in IP5 and CMS

**1m Cu TCTV and TCTH @ z~150m****25mm x 80mm jaws @ 8.4******

**1mW/gm @ 10****6**** p/s**

**150m**

## TCT-Induced Energy Deposition in Triplet Quads and Backgrounds entering CMS/ATLAS

- Peak Energy deposition of 0.35mW/g in Q3 SC coils at MAX @ z~50m @ 106 p/s** **and design spec of Q<0.53mW/gm  max loss rate at TCT ~ 2 x 106 p/s

- ~1000 photons/cm2/s @ 106 p/s scraped ~ physics backgrounds

**Photon Flux**

## Example of New MARS15 RESULTSafter upgrades to Mars code and updates to layout

- Outgoing beam: TCTs are pretty radioactive (especially if made of tungsten) and interfere with the TOTEM first station XRP1 at 146 m.
- Incoming beam: preliminary results for beam-gas are encouraging.

## Task#1: Phase II Metal Collimators

- Design a **COLLIMATOR with ROTATABLE METAL JAWS**
- that we can **cool** to ~<**12kW/jaw**, keeping **T<T****FRACTURE** and** ****P****H2O****<~1 atm**.
- that has reasonable **collimation** system **efficiency** & **good** **impedance**
- that satisfies **mechanical** space & accuracy **requirements**
- that, when **damaged** by a (rare) ASYNCH. BEAM ABORT, can still **rotate** **(max. 360****°)** to present a **clean surface** to the beam

- Scope:
- Tracking studies to understand efficiency and loss maps of any proposed configuration (SixTrack)
- Energy deposition studies to understand heat load under defined “normal” conditions & damage extent in accident (FLUKA)
- Engineering studies for cooling & deformation (ANSYS)
- Construct 2 prototypes with eventual beam test at LHC in 2008
- After technical choice by CERN, engineering support
- Commissioning support after installation by CERN

## SLAC NLC “Consumable Spoiler” as Prototype for Phase II LHC Secondary Collimator

**Differences LC / LHC:**
**Jaw length**
**10cm********100cm**
**Maximum gap &**
**2mm ****** **4.5cm **
**Power deposited**
**10W************12 / 60kW/jaw**

- E. Doyle J. Frisch

## Task Status SummaryTrying to Move from Design Mode to Build Mode

- Original Plan (FY06 Task sheet)
- FY 2004:	Introduction to project
- FY 2005:	Phase II CDR and set up of a collimator lab at SLAC
- FY 2006:	Design, construction & testing of **RC1**
- FY 2007:	Design, construction & no-beam testing of **RC2**
- FY 2008:	Ship, Install, Beam Tests of RC2 in LHC May-Oct 2008 run
- FY 2009:	Final drawing package for CERN
- FY 2010:	Await production & installation by CERN
- FY 2011:	Commissioning support
**RC1=Mechanical Prototype;**** ****RC2: Beam Test Prototype**
- Deliverables listed 10/6/2005
- Final version of RC1 Conceptual Design Report (CDR)
- External review of RC1 CDR
- Thermal tests of single collimator jaw
- Construct and mechanically test RC1
- Performance report on RC1 tests

## FLUKA Energy Deposition StudiesMaterial Study & Input to ANSYS

- Lew Keller

- Use CERN-provided hit maps from tracking program to calculate energy deposited in metal Phase II Secondary Collimators at opened to 7 sigma

## ANSYS 3D Time Dependent Thermal Distortion Studies

- Material & Water temperature and jaw deflection used to specify
- Study materials and material combinations (Copper)
- Axial or Helical cooling schemes (Helical)
- Jaw support schemes (see detailed discussion later)
- Design for beam=1 hour (12kW/jaw for Cu) continuous load with beam=12 min (60kW/jaw for Cu)  transient for 10 seconds

**beam**

**beam**

- Eric Doyle

- 86C

_**Steady State operation**_

## Material thermal performance  (Hollow Cylinder Model)- O.D = 150 mm, I.D. = 100 mm, L = 1.2 m- NLC-type edge supports

## Cu chosen as best balance between collimation efficiency, thermal distortion & manufacturability

**Cu chosen as best balance between collimation efficiency, thermal distortion & manufacturability**

## Adapted to LHC Phase II Requirements

**136mm diameter x 950 mm long jaws (750 mm effective length due to taper).  **
**Vacuum tank, jaw support mechanism and support base derived from CERN Phase I.**

## Helical cooling passages chosen for manufacturability & beamline vacuum safety

**Helical cooling passages chosen for ****manufacturability & beamline vacuum safety**
**Per CERN’s Phase I design – no water-vacuum weld or braze**

**EXTERNAL COIL PERMITS 1 REV OF JAW**

**CERN PHASE I JAW POSITIONING MECHANISM – USE IF POSSIBLE**

**Note: baseline case has hollow core**

##  Baseline Jaw Performance

- Exceeds 200 Max Cu temp

- Possible boiling

- Exceeds 42 max water return temp

- Exceeds Allowed Deflections

- All temperature simulations based on 20C supply.  For CERN 27C supply add 7 to all temperature results.  CERN max water return temp 42C

**Exceeds spec, or other possible problem as noted**

** ****Baseline Jaw Performance**

**Baseline: hollow Cu, 25mm wall, helical cooling - 5cm pitch**

## IR7 secondary collimators heat generation, deflection and effective length

**Deflection and effective length based on ANSYS simulations for TCSM.A6L7.  Power scaled from TCSM.A6L7 according to the distribution on secondary collimators provided by CERN.  Note: first collimator in the series absorbs the bulk of the energy.**** **

**      ****Steady State**

**         ****Transient**

## Adjustable central aperture-defining stop

**Adjustable central aperture-defining stop**

**Stop in/out position controls aperture, actuator external, works through bellows.**

**Leaf springs allow jaw end motion up to 1mm away from beam**

## RF Contact Scheme Blessed by CERN Impedance Police

## Agreement with CERN Team @ 15-June-2005 Meeting despite Known RC1 Unresolved Engineering Issues

- Jaw positioning
- Design concept for central stop: gap adjust, 5 central position float,..
- Bearings & springs attaching jaws to vertical movers
- Load capacity of steppers
- Jaw alignment perpendicular to collimation direction
- Jaw rotation
- Specification of mechanism on crowded jaw
- Force required to rotate jaws against cooling coil
- Misc
- Spring arrangement for H, V, S orientations
- Springs to ensure that device fails open
- Damage assessment mechanism (?)
- Motors, cables, temperature sensors, position probes, ...
- Vacuum requirements of 7.5E-10 torr
- Interference between RF shield and other components

## Progress of Phase II Rotating Collimator Project in first half of FY06

- RC1 Prototype Conceptual Design Report
- reviewed and accepted by CERN and suggestions incorporated
- rf shielding concept approved
- current version 12-12-2005
- http://www-project.slac.stanford.edu/ilc/larp/
- Independent review of project and CDR 12/15/05
- Lou Bertolini-LLNL, Alex Makarov-FNAL, Bill Turner (LBL)
- Charge:
- Is the design presented mature enough that the project can proceed to construct the first prototype?
- Major Findings: http://www-project.slac.stanford.edu/ilc/larp/ReviewersReportFINAL.pdf
- Do not ‘cut metal’ until jaw support, stop and rotation scheme developed
- In progress:  New ideas result in better performance & simplifications
- Check thin-Cu over Stainless for performance √ No improvement
- Increase engineering effort

## Advances since RC1 Baseline

## New Idea to Eliminate Central Stop

- Hub located, in Z, near peak temperature location, which lowers peak temperature, reducing gradient and bending.
- Both ends of jaw deflect away from beam.
- Total deflection reduced if the shaft deflection can be minimized
- Cooling coils embedded in I.D. of outer cylinder.

## Evolution of jaw-hub-shaft25mm deep cooling tubes

- SS 1hr beam

- Transient 10sec @12min beam

- RC1 – not a practical support scheme

- More              realistic

- Note reduced shaft end deflection – a positive result if stop is used

- Next for jaw-hub-shaft:
- Alternative materials to reduce shaft deflection

## NLC Jaw Indexing Mechanism

- Reciprocating linear motion advances jaw by one or more ratchet pitches.  **LHC system will require opposing ratchet to hold jaw position against cooling tube deformation torque.  Mechanism probably will be designed to actuate only when jaw fully retracted.**

## Personnel Issues

- Full time engineer (Steve Lundgren) and full time designer hired 3 April
- Several post doc and fixed term candidates interviewed
- Spending in SLAC shops has begun for thermal tests

- Active Manpower:
- Eric Doyle-Engineering (0.25)
- Lew Keller-FLUKA (0.25)
- Steve Lundgren-Engineering (1.0)
- Tom Markiewicz- Integration (0.20)
- Designer (1.0)

- Meeting/advice:
- Tor Raubenheimer
- Andrei Seryi
- Joe Frisch
- Yunhai Cai-Tracking

- Planned hires:
- Postdoc#1

- Future Effort:
- Controls Engineer

## Current Experimental Activities Consistent with Review Committee Dictum to Delay Construction Until Mechanical Design Complete

**Current Experimental Activities Consistent with Review Committee Dictum to Delay Construction Until Mechanical Design Complete**

- Braze tests of cooling coils in progress: procedures defined
- Prep for full cooling & deformation tests: parts & lab defined
- Acquisition of Phase I support & mover assemblies: quote “in the mail”
- Remodeling of CERN parts for interface to US parts: designer

- Note faceted face: Vertical Alignment & “Drip Edge”

## Brazing Tests

## Concept to Eliminate 4-Loop Coils at Ends

**Concept to Eliminate 4-Loop Coils at Ends**

## Reinvigorated Focus on Extent of Damaged Region in the case of the Accident

**2000um 500 kW 20 GeV e- beam hitting a 30cm Cu block a few mm from edge for 1.3 sec  (0.65 MJ) **

**FNAL Collimator with .5 MJ**

## Keller, Doyle

**Cross Section at Shower Maximum Showing ****Copper**** ****Melting**** and Possible ****Fracture**** Regions in a Mis-steering Accident**

**Copper**
**Jaw**

**Melting zone (grey),**
**radius = 3.3 mm**

**Fracture zone, ****(200 C)**
**radius = 7 mm**

**2.5 cm**

- ~1MJ

## Inter-Lab Collaboration

- Good will & cooperation unfortunately limited only by busy work loads
- CERN review of SLAC draft CDR
- CERN participation in RC1 CDR review
- Monthly video meetings
- Drawing of support structures for H, V Skew transferred
- Many technical exchanges via email
- Discussions on how to improve communication delays in progress
- Acquisition of parts will be crucial to delivering prototypes on time
- French vendor of collimator jaw assembly has been contacted to negotiate price/delivery for shipment to SLAC: reply immanent
- CERN feels that a spare support (Bulgarian company(?)) can be sent without much trouble
- Plans for damage tests before final delivery date may need to be made
- Participation in Fall 2006 Phase I testing under discussion

## Phase II Project at CERN

- CERN Phase II program is beginning
- CERN will concentrate on alternative metal designs
- A decision on which course to pursue will be taken after operational experience with Phase I system, LHC performance, and beam tests of several prototype designs are considered
- In all cases, knowledge from SLAC Phase II prototype is deemed valuable input and regardless of final technology choice for Phase II, SLAC will participate in Phase I & Phase II commissioning.
- Review committee concerned that
- Specifications, deliverables, agreements be codified in writing
- When design complete, will enter into CERN EDMS (eg. Ratti et al)
- SLAC will always lose to CERN in a technology down-select
- Hermann Schmickler promotes effort to a “LARP Hard Deliverable”

## Phase II Task Summary

- Project has slipped 6 months in 6 months due to
- Reality of hard deliverables as opposed to softer “design” milestones
- Staffing delays: failed job offers, safety mandates, personal issues ...
- Understandable design requests by review committee
- Nothing we didn’t know about
- Budget “slipped” 6 months or $430k as well
- After taking this hit we believe we are on-track to deliver on new schedule
- Nervous now about accident condition: begin to discuss beam tests
- Believe various steady state requirements are attack-able on an “as good as can be engineered” basis
- Excellent recent ideas simplify design and increase performance x5
-  Expect thermal tests and completely tested RC1 device by end of FY06 and mid-FY07, respectively
- Need to get full Phase I mechanism from CERN vendor if we are to make RC2 deliver schedule. If SLAC can concentrate on jaws and have rest of infrastructure provided RC2 can meet LHC schedule.
- Slippage hopefully consistent with CERN’s newest schedule

## Task #4: Irradiation Damage Assessment of LHC collimator materials

_**Scope: **_
**Irradiate 2-D weave carbon-carbon and exact graphite used in Phase I jaws plus materials considered viable for Phase II jaws**
- BNL AGS/BLIP (70 A of 117 & 200 MeV protons)
**Measure material p****roperties: thermal expansion, mechanical properties, thermal conductivity/diffusivity and thermal shock**
- BNL “Hot Cell” Sample Measurement Facility
_**Resource Requirements:**_
- BLIP Irradiation charges & hot cell measurement facility use fees
- Sample acquisition and preparation
- Measurement apparatus improvement
- Personnel costs
_**Timescale:**_
- 2005,2006 proton runs + analysis into FY2007

## BNL Irradiation (BLIP) and Post-Irradiation Testing Facilities and Set-Up

**Layout of multi-material irradiation matrix at BNL BLIP**

**Test Specimen Assembly**

**Remotely-operated tensile **
**testing system in Hot Cell #2**

**Dilatometer Set-up**
**In Hot Cell #1**

## Task #4 Status

_**Completed:**_
**Phase I Carbon-Carbon irradiation**
**Sample activation measurements (mCi, dpa)**
**Thermal Expansion of C-C specimens**
**Preparation of Phase II material samples**
_**In Progress:**_
**Set up of existing tensile test apparatus & test of irradiated C-C**
**Set up of new thermal conductivity apparatus**
**2006 Run if Phase II materials in BLIP begun May 4, 2006**
**Thermal Expansion on Phase II materials that have not been irradiated**

- Specimens highly degraded under dose>> LHC collimator jaws will see.

## CTE Measurements of Irradiated C-C

- Strong (fiber plane) direction

**Irradiation Damage** **Self Anneals through thermal cycling in both strong and weak directions**

- 7.50 mCi

- Weak (┴fiber plane) direction

## Materials for May 2006 BLIP Run are Ready

**Primary Phase II Materials:**** **
- Annealed Copper
- Glidcop (0.15% Al – balance Cu)
**Other Potential Phase II Materials:**
- Super Invar
- Gum Metal
**Other Materials to be (re)tested**
- 2D Carbon-Carbon
- 3D Carbon-Carbon

## New Measurement Equipment

- Thermal Conductivity Measurements Using the Laser Flash Method
- Laser already in the Hot Lab
- Experimental Safety Review is taking place at BNL
- Grad Student from SUNY/SB joined the team
- Tests are planned for summer and fall FY06

## Jaw Damage Studies(an increase in scope)

**Simulations of Extreme Energy Deposition **
**(jaw damage case) Using LS-DYNA**

**Measurements of laser induced ablation of Cu and comparison with LS-DYNA**

## Conclusion

- The four LARP Collimation program tasks
- Provide R&D results to a key LHC subsystem that will need to perform well from the beginning
- Strong support for all tasks from LHC Collimation group
- Play to the unique strengths of the US Labs
- RHIC as a testbed
- BNL irradiation test facilities
- Fermilab’s simulation strength
- SLAC’s Linear Collider collimator engineering program
- Concerns
- Manpower at BNL for tracking or else nothing will happen
- Timeliness of FNAL simulations for input to Phase I design choices
- Adequate funds for BNL irradiations studies
- Aggressive schedule for a demanding “hard deliverable” prototype Phase II metal collimator
- Currently far from kind of results you have seen from Instrumentation & Magnet groups

## Bonus Slides

## IR7 Collimator Layout11 Carbon Phase I and 11 Metal Phase II Secondary Collimators per beam in IR7

## LHC Beam Dump Abort System

- R. Schmidt
- HALO ‘03

## # Bunches on Collimators   Delay in Retriggering Dump Kicker

- J.-B. Jeanneret
- HALO ‘03

- t now < ~0.7 s      8 bunches on colls

**Carbon-Carbon Jaws Chosen for Phase I as they will survive hit by 8 bunches**

## LHC Phase I 25x80mm2 Carbon/Carbon Secondary Collimators cooled for 7kW DC

## LHC Phase I 25x80mm2 Carbon/Carbon  Secondary Collimators w/ 7kW cooling Prototypes Made & TestedFull Order Placed

## Jaw Positioning Forces – Phase I => Phase II

**Jaw Positioning Forces – Phase I => Phase II**

**Jaw end springs will be sized as com-promise  1) bending-generated force applied to nut   2) static deflection due to jaw weight**

**Pull-in headroom expressed as force at nut**

**Upper jaw - shown**

**Lower jaw**

**Jaw deflection = 400 um for 1 hr beam lifetime case, 1200 um for 10 sec transient @12 minute lifetime power level**

## Bimetallic jaw (SST/Cu): no benefitSolid Cu beneficial

**Bimetallic jaw (SST/Cu): no benefit****Solid Cu beneficial**

**SST/Cu**

**Baseline Hollow Cu**

**SolidCu**

**No benefit from SST core – same CTE as Cu, poor conductivity – temperature distribution unchanged.  Cu core => alt heat path to opposite side, reduces ********T therefore bending.**

## Alternative Shaft MaterialsShaft supported case - No Major Improvement

**Alternative Shaft Materials****Shaft supported case -**** ****No Major Improvement**

- Deflection is combo of bending & swelling

## Alternative Shaft MaterialsCentral stop-supported case - No Improvement

**Alternative Shaft Materials****Central stop-supported case - No Improvement**

## Crystal Collimation Proposal

- Stages:
- Stage 1: feasibility study itself
- Stage 2: design of the LHC Phase II Collimation system
- Goal: deliver a report (of a mini-review?) by next LARP collaboration meeting (~ April 2007), be in position to decide whether to proceed to Stage 2
- Plan:
- Prepare and perform bent crystal experiments at Tevatron in Fall 2006
- Prepare and perform crystal characterization experiment at SPS H8 line in Sep’06
- Data processing and analysis
- Theory work and code development for the LHC