larp collimator tasks summary 28 april 2006 larp collaboration meeting-lbl tom markiewicz slac bnl -...

LARP Collimator TasksSummary

28 April 2006

LARP Collaboration Meeting-LBL

Tom MarkiewiczSLAC

BNL - FNAL- LBNL - SLAC

US LHC Accelerator Research Program

LARP Collaboration Meeting. - 28 Apr. 2006 Collimator Task Summary - T. Markiewicz Slide n° 2 / 27


Take Home Points

Phase II Rotate-able Collimators– Elevated to “Hard Deliverable Status” in eyes of our CERN colleagues – Schedule slippage of ~6 months

• Manpower issues

• Review committee issues (more complete design before can start)

– 400k$ returned to LARP general fund– Now on track & better staffed– Consensus that we need more effort to understand 1 MJ beam-abort

on jaw

Communication with CERN slower than ideal (see Nikolai’s comments later)– Should we ask Ralph to appoint a “Point of Contact”?

New Task 5 proposed: Crystal Collimation– To be examined by Gang of 5+1: (4 x L2 + VS) + S

• Impact on “baseline” secondary collimator


Task 2: Progress Since October 2005 Meeting

State of affairs Oct. 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 jobNew 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 IRsOther 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

-100 -50 0 50 100 150 200 250 3000

0.5

1

1.5

2

2.5

3

3.5

4

Lo

g o

f lo

ss

es

(a

rb. u

nit

s)

distance from PHENIX (m)

Comparison ICOSIM (black) with BLM data during gap cleaning

PH

EN

IX

PH

OB

OS

12 o

'clo

ck

BR

AH

MS

4 o

'clo

ck

S

TA

R

Ions Agree

With

“ICOSIM”

Protons Data does not agree


TERTIARY COLLIMATORS- October 2005 Status

Tertiary collimators (TCT) at 8.4 around IR1/5 protect SC triplets from tertiary halo coming from particles leaking from 7 secondary collimators, upstream beam-gas and inefficiency of MPS if unsynchronized beam abort. These must not induce peak energy deposition in the triplets above the quench limit nor induce detector backgrounds.

80 x 25 x 1000mm Cu jaws at .4s 145m from IP added to MARS15

Without TCTs With TCTs


Example of New MARS15 RESULTSafter 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.


TERTIARY COLLIMATORS PROGRESS & PLANS

In October 2005, Nikolai wrote:

– File of Beam1 loss in TCT region calculated by CERN received 2005-09

• Need similar file for Beam2

• Need similar files for momentum cleaning insertion IR3

– Plan to begin updating results using these files beginning mid-October

Today Nikolai writes Need input from Ralph ASAP

- it’s not the first time – obviously a communication issue As soon as beam loss input files received ~2 mos to finish most work

on TCT If no surprises – task can be closed ~1/2 yr

6 months without requested information


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 (117 & 200 MeV protons)

Measure material properties: thermal expansion, mechanical properties, thermal conductivity/diffusivity and thermal shock• BNL Hot Cell Sample Measurement Facility

Status October 2005:– Phase I Carbon-Carbon irradiation completed– Sample activation measurements completed– Thermal Expansion of specimens started

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

Mechanical Testing Equipment (Stress vs. Strain) to be

reintroduced to the Hot Lab

+

Thermal Conductivity Measurements Using the Laser Flash MethodLaser already in the Hot LabExperimental Safety Review is taking place at BNLGrad 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


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


Status of Phase II Rotating Collimator Project at 10-06-2005 Pheasant Run LARP Mtg.

SLAC and CERN agree on an initial set of specifications for the first mechanical prototype RC1– Put a new vacuum tank with cylinder jaws that fits LHC spatial constraints on a

CERN Phase I base and use CERN Phase I scheme for jaw alignment and cooling input

– Provide 12kW cooling to each 136mm x 95cm jaw through flexible tubing– Relax 25um flatness tolerance but provide flexible jaw support and a central

stop mechanism to ensure thermal bowing is AWAY from beam• 400 um sagitta for 1 hr beam lifetime engineering steady state• 1200 um sagitta for 12min beam lifetime 10 second transient


FY06 Goals of Phase II Rotating Collimator Project and Beyond

Work Plan outlined 10/6/20061. Single jaw thermal test: one jaw with internal helical cooling

channels to be thermally loaded for testing the cooling effectiveness and measuring thermal deformations.

2. Full RC1 prototype: a working prototype for bench top testing of the jaw positioning mechanism, supported to simulate operation in all necessary orientations, but not intended for mounting on actual beamline supports with actual beamline, cooling, control and instrumentation connections.

Deliverables listed 10/6/20051. Final version of RC1 CDR: Awaiting support/stopper design

2. External review of RC1 CDR: √

3. Construction & Performance report on RC1: Xmid FY07• Progress delayed ~6 months due to reviews & manpower issues


Jaw/Cooling Tube Joint Development

Purpose: determine appropriate joint configuration & fabrication methods

In process.. target completion date •Square hollow magnet conductor for first test ~ 9 mm x 9 mm

•Copper jaw and mandrel

•Cu-Au braze

•After first braze, machine coil o.d. for correct fit to jaw i.d.

•After second braze, section assy to inspect coverage

•Round tubing with grooved (?) mandrel is next

May 9th

Cooling Tube

Jaw Center Mandrel

~100 mm

~70 mmdia

~100 mm dia


Single Jaw Thermal Test setup

Reference bar, water cooled to maintain straightness (radiation shield ?)

Standoffs fix jaw distance to reference bar at center

Capacitive proximity sensors at ends

Flexible end mounts

2 x 5 kW heaters, coupled with thermal grease

Orientation: may be rotated 90o, or 180o or on end

Thermocouples measure temperature distribution

Water cooling


Single Jaw Test Thermocouple Locations

•Thermocouples recessed into Jaw slightly below the surface

•Spaced along Heater length and around Jaw circumference

•Should yield the Jaw heating profile predicted by the FE analysis

12 x Thermocouples

2 x 5kW Heaters


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.

No. name Power (kW)

Defl (um)

Eff. Lngth (cm)

Power (kW)

Defl (um)

Eff. Lngth (cm)

note

1 TCSM.A6L7 11.7 394 43 58.5 1216 24 simulated 2 TCSM.B5L7 2.7 137 75 13.5 422 46 scaled 3 TCSM.A5L7 .69 35 75 3.44 108 75 scaled 4 TCSM.D4L7 .18 9 75 .92 29 75 scaled 5 TCSM.B4L7 .20 10 75 1.01 31 75 scaled 6 TCSM.A4L7 .19 10 75 .96 30 75 scaled 7 TCSM.A4R7 .16 8 75 .81 25 75 scaled 8 TCSM.B5R7 .22 11 75 1.10 34 75 scaled 9 TCSM.D5R7 .19 9 75 .93 29 75 scaled 10 TCSM.E5R7 .13 6 75 .62 19 75 scaled 11 TCSM.6R7 .25 12 75 1.23 26 75 scaled

Steady State Transient


Unresolved Jaw Support Issues

Support needs to:

•hold ~100kg jaw to 5-10um accuracy

•not sag under gravity for vertical and skew orientations

•permit ~1200 um flex for 10 second bursts of 60kW energy deposition

•work with torque of Phase I stepping motors


Jaw Positioning Forces – Phase I => Phase II

Pull-in force

0

500

1000

1500

2000

2500

3000

3500

4000

0 20 40

x (mm)

F (

N) Fin

Fres

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 force

0

500

1000

1500

2000

2500

3000

3500

4000

0 20 40

x (mm)

F (

N) Fin

Fres

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


Unresolved Central Stop Issues

Interplay between alignment scheme

•independent motion of each end of each jaw

and stop

•must be on beam centerline

•this can vary ±5mm/ store

Reproducibility of alignment on successive stores

May use two stops to control tilt

Slot deep enough to avoid damage in accident

Stop far enough from beam to never be damaged & is out of way at injection


Unresolved Issues with Jaw Rotation

Torque required to rotate 360 understood and is substantial;Coil “creep” may alleviate.

Details of actuator not yet worked out

Interference with RF parts and gross jaw adjustment during injection not studied


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.


2.5 cm

Missteered beam (9E11 protons)on secondary Jaw

CopperJaw

Cross section at shower max.

Copper

Fracture temp. of copper is about 200 deg C

What is the damage area in a missteering accident?

FNAL Coll

with .5 MJ

~1MJ


Phase II Task Summary

Project has slipped 6 months in 6 months due– Reality of hard deliverables as opposed to softer “design” milestones– Difficulty/cost of acquiring manpower– Understandable design requests by review committee

• Nothing we didn’t know about

Budget “slipped” 6 months as wellAfter taking this hit we believe we are on-track to deliver on new schedule

– Most 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

Expect thermal tests and complete design 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.

larp collimator tasks summary 28 april 2006 larp collaboration meeting-lbl tom markiewicz slac bnl -...

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