SLAC Phase II Secondary Collimators 6 October 2005 LARP Collaboration Meeting-St. Charles, IL Tom...

SLAC Phase II Secondary Collimators

6 October 2005

LARP Collaboration Meeting-St. Charles, IL

Tom MarkiewiczSLAC

BNL - FNAL- LBNL - SLAC

US LHC Accelerator Research Program

LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 2 / 47

Task#1: Studies of a Rotatable Metallic Collimator for Possible Use in LHC Phase II

Collimation System

If we ALLOW (rare) ASYNCH. BEAM ABORTS to DAMAGE METAL JAWS, is it possible to build a ROTATING COLLIMATOR

– that we can cool to ~<10kW, keeping T<TFRACTURE and PH2O<1 atm.

– that has reasonable collimation system efficiency– that satisfies mechanical space & accuracy requirements

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 & MARS)– Engineering studies for cooling & deformation– Construct 2 prototypes with eventual beam test at LHC in 2008– After technical choice by CERN, engineering support– Commissioning support after installation by CERN


Task#1: Timescale & Manpower

FY 2004: Introduction to projectFY 2005: Phase II CDR and set up of a collimator lab at SLACFY 2006: Design, construction & testing of RC1FY 2007: Design, construction & no-beam testing of RC2FY 2008: Ship, Install, Beam Tests of RC2 in LHC May-Oct 2008 runFY 2009: Final drawing package for CERNFY 2010: Await production & installation by CERNFY 2011: Commissioning supportRC1=Mechanical Prototype; RC2: Beam Test Prototype

Engineer#2

Postdoc#1

Active Manpower:Eric Doyle-EngineeringLew Keller-FLUKAYunhai Cai-TrackingTom Markiewicz- Integration

Meeting/advice:Tor RaubenheimerAndrei SeryiJoe Frisch

Planned hires:Mech. Engineer#2Postdoc#1

Future Effort:Controls EngineerDesigner


2005-06-01 DOE Review of Collimation Program: A+

"The activity in collimation is impressive, with the work being approached in a very professional manner. It is a critical problem, and solving it will have great impact on the ability of the LHC to reach design luminosity. Even the task sheets for this project were done very professionally, lending confidence in a well-managed and well-focused activity. (The synergy with the ILC is clearly evident here.)"


Status of Phase II Collimator Conceptual Designat 2005-06-01 DOE Review

Adequate software in place and MANY studies have been done but …

We do NOT yet have a conceptual design for the 1st of the 11 collimators needed (per beam) in IR7– 28 of 30 Phase II collimators will not have a heating problem

• No magic design or material which could simultaneously provide good efficiency with combination of energy absorption, thermal conductivity, & thermal expansion to maintain 25 um flatness tolerance over length of jaw during 1hr/12min (90/450kW) beam lifetime transients for nominal jaw length (1m) and gap setting (7)

• Focus on – 150mm O.D. 25mm wall Cu jaws with helical cooling tubes– 150mm O.D. “solid” Cu jaws cooled with axial flow over 36° of arc


Copper

Similar result was obtained by Ralph Amann

Yunhai Cai

Study of Material for Secondary Collimators

• High Z materials improve system efficiency •Copper being considered because its high thermal conductivity

• Available length is about 1 meter

• Achievable efficiency is about 3.5x10-4 at 10

•As Sixtrack program adds absorbers/tertiary collimator we expect ~x10 improvement


Energy Deposition in Metal Phase II Secondary Collimators w/ Carbon Phase I

Collimators Open Calculated in FLUKA using CERN-provided input file

Beam 1

Beam 2

Primary collimators

First group ofsecondarycollimators

40 m

dipoles

IR-7

Z (cm)

X (

cm)


Power absorbed in one TCSH1 jaw at 10 when 80% (5%) of 450kW of primary beam interacts

in TCPV (TCSH1)

kW Deposited in TCSH1 upper right jaw vs. length

0.01

0.10

1.00

10.00

100.00

0 20 40 60 80 100 120

Z (cm)

kW

/5 c

m

Al

W

Cu-H2O

Cu, 7 sig

Ti

Cu

Be

CuBe


Limited cooling arc: free wheeling distributor – orientation controlled by gravity – directs flow to beam-side axial channels.

Pro: Far side not cooled, reducing T and thermal distortion.

Con: peak temperature higher; no positive control over flow distributor (could jam); difficult fabrication.

360o cooling by means of helical (or axial) channels.

Pro: Lowers peak temperatures.

Con: by cooling back side of jaw, increases net T through the jaw, and therefore thermal distortion; axial flow wastes cooling capacity on back side of jaw.

water

beam

Helical and axial cooling channels


ANSYS thermal and structural results for full ID cooling and limited cooling arc showing 64% less

distortion with limited cooling

61C

x=221 m

Spec: 25msupport

support

89C

x=79 m

Note more swelling than bending

Note transverse gradient causes bending

Note axial gradient

64% less distortion

360° cooling

of I.D.

36° cooling

arc


material

cooling arc (deg)

power (kW) per jaw

Tmax ( C)

defl (um) Tmax water side( C)

max flux (W/m^2)

power (kW)

Tmax ( C)

defl (um) Tmax water side( C)

max flux (W/m^2)

BeCu (94:6) 360 0.85 24 20 4.3 41 95Cu 360 10.4 61 221 43 2.7E+05 52 195 829 117 1.2E+06Cu - 5mm 360 4.5 42 117 39 2.3E+05 22.4 129 586 117 1.2E+06Cu/Be (5mm/20mm) 360 5.3 53 161Super Invar 360 10.8 866 152 60Inconel 718 360 10.8 790 1039 66 54 1520 1509 85Titanium 360 7.4 214 591 42 36.8 534 1197 77Tungsten 360 14.9 183 95 79 74.5 700 335 240 2.6E+06Al 360 3.7 33 143 18.5 73 5272219 Al 360 4.6 34 149 26 7.1E+04 23 79 559 46 3.1E+05C R4550 360 0.6 25 5 3.0 41 20

BeCu (94:6) 90 0.85 25 8 4.3 41 86

BeCu (94:6) 36 0.85 27 2 4.3 46 101Cu 36 10.4 89 79 67 5.6E+05 52 228 739 139 1.4E+06Cu - solid 36 10.4 85 60 65 5.3E+05 52 213 5422219 Al 36 4.6 43 31 23 89 492Al - solid 36 3.7 40.8 31 18.5 80 357

10, primary debris + 5% direct hits

SS @ 1 hour beam life transient 10 sec @ 12 min beam

Material Comparison SS & Transient Thermal Deflection ANSYS simulation results for 150mm

OD x 100mm ID x 1.2m L

Notes:1. BeCu is a made-up alloy with 6% Cu. We believe it could be made if warranted2. 2219 Al is an alloy containing 6% Cu3. Cu/Be is a bimetallic jaw consisting of a 5mm Cu outer layer and a 20mm Be inner layer4. Cu – 5 mm is a thin walled Cu jaw5. Super Invar loses its low CTE above 200C, so the 152um deflection is not valid6. Heat flux to water of 10^6W/m^2 or greater is in regime of possible film boiling


Material evaluations compared to Cu based on 150mm x 1200mm x25mm wall model

Material Reasons for rejection in favor of Copper

BeCu (6% Cu-loaded Be)

Beryllium is forbidden by CERN management, low cleaning efficiency due to few particles absorbed; fabrication difficulty

Super Invar Poor thermal conductivity high temperature (866°C), desirable properties (low thermal expansion coefficient) disappear at 200°C

Inconel 718 Poor thermal conductivity high temperature (Tmp = 1400°C < 1520°C transient peak) & very high deflection (1039um SS, 1509um transient)

Titanium Poor thermal conductivity deflection 2.7 x Cu (591um, SS)

Aluminum Relatively poor cleaning efficiency, water channel fabrication difficulty

Tungsten High temperature on water side (240°C - 30bar to suppress boiling); high power density - can't transfer without boiling


Directions under investigation & negotiation at time of 2005-06-01 DOE Review

• Redefine secondary hybrid system to treat 1st collimator as special – Break 1st secondary into two (unequal?) lengths of perhaps different

materials– Grooved “expansion slots” to limit deformation– Adjust gaps of the first carbon & metal secondary to reduce heat load

while maintaining efficiency with remainder of secondary system– Keep 1st C-C secondary collimator’s jaws at 7 and leave out 1st metal

secondary collimator– Relax deformation tolerance relaxed to if jaws expand AWAY from beam

• Begin to deal with LHC infrastructure & operational constraints– 45mm jaw gap at injection incompatible with NLC inspired

circumferentially mounted gap adjustor• Look into adopting Phase I adjustment mechanism

– Spatial constraints of LHC beam pipes & tunnel a challenge• Jaw dimensions, tank dimension


IR7 Collimator Layout

Beam Direction

Primary Collimators

Hard Hit Secondary Collimators


Possible Path to Immediate RC1 Prototype: Leave TCS#1 Carbon-Carbon, Remainder Cu

Relative Energy Deposition in C-C Secondary Collimators in IR7 [P(1)=23kW at 4E11 p/s]

0

0.2

0.4

0.6

0.8

1

1.2

0 5 10 15 20 25

Collimator Number

P/P

(1)

Beam 1

Beam 2

Inefficiency 1C-10Cu All Cu

Horizontal 2.84x10-4 3.72x10-4

Vertical 3.63x10-4 4.36x10-4

Skew 4.57x10-4 3.85x10-4


Concentrating E_dep in Front Part of Jaw

COPPERkW Deposited in TCSH1 upper right jaw vs. length

-1.00

1.00

3.00

5.00

7.00

9.00

11.00

0 20 40 60 80 100 120

Z (cm)

kW/5

cm

77% on TCPV, 6.7% on TCSH1, 77 kW

77% 0n TCPH, 1.5% on TCSH1, 58 kW

77% on TCPS, 6.0% on TCSH1, 92 kW

77% on TCPV, 6.7% on TCSH1, 70 kW, Carbonpre-radiator

CARBON-TUNGSTENkW Deposited in TCSH1 upper right jaw vs. length

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

0 4 8 12 16 20 24 28 32 36 40 44 48

Z (cm)

kW

/2 c

m

on TCPV, 6.7% on TCSH1, 61 kW 77%


De

flectio

ns re

ferre

d to

sha

ft

Notes:

“Solid” jaws – 150mm OD x ~24mm ID. Basic jaw 120cm L

Aperture transition from 10 to 77cases based on CERN ray files for interactions in TCPV

pre-radiator not used – Phase I carbon jaw to concentrate energy toward front of Phase II jaw.

Effect of: shortened jaws, wider gap, jaw support scheme

De

flectio

ns re

ferre

d to

ed

ge

basic jaw 120cm L


Circumferential grooves reduce bending deflection by interrupting continuity of thermal strain.

Case Tmax °C Deflection (um)Jaw edge ref axis ref

Straight 59.5 33 ~100

grooved 59.5 15 ~74

Parameters

150mm O.D., 25mm wall, 120cm long

Grooves: 10mm deep, 50mm spacing

10kW heat, evenly distributed

45 deg cooling arc


Mechanical Model 2005-06-01 Used NLC Concept of Central Strongback with mid-

collimator jaw gap adjuster

beam

beam


June 15-17 CERN/SLAC Collaboration Meeting

Attendees– CERN: Ralph Assmann (Project Leader, Tracking), Allesandro

Bertarelli (Mechanical Eng.), Markus Brugger (Radiation Issues), Mario Santana (FLUKA)

– SLAC: Tom Markiewicz, Eric Doyle (ME), Lew Keller (FLUKA), Yunhai Cai (Tracking), Tor Raubenheimer• Radiation Physics Group: Alberto Fasso, Heinz Vincke

Results– Agreement on basic design of RC1 (1st rotatable prototype)– Transfer of many of CERN mechanical CAD files– Lists of

• Further studies required

• Outstanding Engineering Issues requiring more design work

• Project Milestone List & Action Items List

– Test Installation of “New FLUKA”


Conceptual Design of RC1 (1 of 2)

Mechanics must fit within CERN Phase I C-C envelope– 224mm center-to-center with 88mm OD beampipes– 1480mm longitudinal flange-to-flange– 25mm adjustment/jaw (22.5mm relative to beam w/±5mm allowed beam

center motion and use Phase I alignment and adjustment scheme

– Two 75cm Cu cylindrical jaws with 10cm tapered ends, 95cm overall length with axes connected to vertical mover shafts

– 136mm OD with 9mm taper– Each jaw end independently moved in 10um steps– Vacuum vessel sized to provide 8mm clearance to adjacent beam and

allow gross/fine 0°, 45°, 90° positionsRelaxed mechanical deformation specifications

– <25 um INTO beam guaranteed by adjustable mechanical stop(s)• Ride on groove deep enough to not be damaged in accident case• Adjustable between ±5 and ±15 sigma (2-6mm) & centered on beam

– <325 um (750um) AWAY FROM beam @ 0.8E1p/s loss (4E11p/s)• Flexible support on adjustment


Conceptual Design of RC1 (2 of 2)

Assumed worst case heat load (FLUKA)– 11.3 kW/jaw steady state, 56.5kW/jaw transient (10 sec)

Cooling boundary conditions– 200 °C maximum temperature of Cu– 27 °C input H2O temperature– 42 °C maximum allowed return H2O temperature

Two Cooling Schemes under consideration– Helical tube: more secure H2O-vacuum interface– Axial channels w/ diverter: superior thermal mechanical performance– Sufficient pressure (3 atm.) to prevent local boiling in transient– Flexible supply lines to provide 360° rotation

Other– Vacuum: <1E-7 Pa (1.3E-5 torr)– RF: shielding scheme has been proposed


Proposed layout: 136mm diameter x 950mm long jaws, vacuum tank, jaw support mechanism and

support base derived from CERN Phase I


Vacuum tank enlarged to accommodate jaw motion. Relative location of opposing beam pipe – near interference in skew orientations 10° deviation


Based on CERN’s design – no weld or braze between water & vacuum

• Tube formed as helix, slightly smaller O.D. than jaw I.D.

• O.D. of helix wrapped with braze metal shim

• Helix inserted into bore, two ends twisted wrt each other to expand, ensure contact

• Fixture (not shown) holds twist during heat cycle

Variations:

1. Pitch may vary with length to concentrate cooling

2. Two parallel helixes to double flow

3. Spacer between coils adds thermal mass, strength

4. Electroform jaw body onto coil

Helical cooling passages – fabrication concept


•Stop prevents gap closing as jaw bows inward due to heat

•Jaw ends spring-loaded to the table assemby … move outward in response to bowing

•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

Adjustable central gap-defining stop


Swelling vs. bending deflectionEffect depends on jaw support scheme


Self aligning bearing

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

Adjustable central jaw stops (not shown) define gap

Flexible bearing supports allow jaw thermal distortion away from beam

CERN’s jaw support/positioning mechanism. Vacuum tank, bellows, steppers not shown.

Flexible end supports used in conjunction with central gap-defining mechanism


Rigid round-square transition

Spring loaded fingers ground two jaws through range of motion

Jaw support & gap adjustment borrowed from CERN

RF Contact Overview


Flexure – ramp follows jaw motion – sliding contact with jaw and top/bottom walls

Step may be detrimental to RF performance

Stationary top & bottom walls

RF contacts – cutaway view


RAMP WRAPS 180o

STEP ELIMINATED

RF contact variation removes step


Clearance problems with RF contacts

Jaw Support Concept – unresolved issues interferences with RF parts


CERN design:

Jaw supported on individually moveable shaft at each end, controlled by steppers external to tank.

Bellows allows full range of jaw motion

Continuous one-piece cooling tube brazed to jaw, exits tank at each end through shaft.

Unresolved interferences between RF parts and cooling and support parts

Jaw rotation mechanism not devised

Substantial forces to rotate jaw

Mandrel to support coil not shown

Flex cooling supply tube concept


Contiguous with helical tube inside jaw.

Formed after assembly-brazing of jaw and installation of bearing on stub-shaft

Exits through support shaft per CERN design

Material: CuNi10Fe1, 10mm O.D., 8mm I.D.

Stub-shaft (bearing not shown)

Support shaft

Detail of flex cooling supply tube

Relaxed (as shown)

# coils 4

O.D. 111mm (4.4in)

full 360° rotation # coils 5

O.D. 91mm (3.6in)

torque 9.1N-m (81in-lb)


Primary

Collimator

(source)

TCSM.B6.L7 Jaws at 7 TCSM.B6.L7

Jaws at 10

Copper Al_2219 Copper Al_2219

TCP.D6.L7

(TCPV)

73

26

51

19

TCP.C6.L7

(TCPH)

61

22

49

19

TCP.B6.L7

(TCPS)

92

28

56

20

Power Deposition on First 120cm Secondary Collimator in 12 Min. Lifetime from 20cm C primary

hit files (kW per jaw)

Notes:

1. Collimator data, ray files, and loss maps from LHC Collimator web page, Feb. 2005.2. Must add contribution from direct hits on secondary jaws.

Sensitivity to aperture

and to source of

halo: H, V, or S

56.5kW/jaw (11.3kW/jaw for 1 hr beam

lifetime) assuming 80%-5%

interaction ratio split

from 20cm primary hit maps, but

adjusting for hadron

absorption in back 40cm of C primaries

and adjusting for shorter

95cm length


Continuing evolution of ANSYS model to include realistic cooling channels and cooling water

response to heat generated by beam

beam

2x 5mm sq channels

136mm

x 950mm long

“Solid” jaw has less T across diameter and short cut for heat flow

H2O simulation – helical flow shown

Fluid pipe elements:

Water temperature responds to heat absorbed from jaw

More realistic simulation

Axial pipes can simulate axial flow

Friction can be simulated


Compact (136x950) jaw variations - performance comparison

material coo

lin

g a

rc (

deg

)

po

wer

(kW

) p

er j

aw,

no

min

al

Tm

ax (

C)

Tm

ax w

ater

sid

e (

C)

def

l (u

m)

po

wer

(kW

)

Tm

ax (

C)

Tm

ax w

ater

sid

e (

C)

def

l (u

m)

Cu - solid, 150x1200 37 10.4 85 65 60 52 213 542

Cu, solid, 150x1200, original model 36 10.4 87.6 66 49.5 52 208.4 127 494

Cu - solid, 150x1200 36 11.3 89.1 67 49.5 57 210.2 129 520

Cu-solid, 136x950 40 11.3 92 71 53 57 213 133 526

Cu-solid, 136x950 53 11.3 80 59 54 57 203 126 525

Cu solid, 136x950, 2 channels - 11.3 84 60 73 57 201 104 551

Cu solid, 136x950, 2 ch, fluid pipes - 11.3 85 55 63 57 201 86 540

Cu, 136x71x950 (18 ax chan ~helix) - 11.3 58 40 179 57 178 99 688

Cu, 136x71x950 (helical), fluid pipes - 11.3 78 281 57 205 869

10 , primary debris + 5% direct hits

original mapping scheme benchmarks

simulated beam side-only cooling

simulated all-around cooling (helical flow)

7 , 77% on 60cm prim TCPV, 6.7% direct hits


Final Expected Performance of RC1 Design

Table 3. Axial cooling (36o arc) vs helical cooling: 136mm x 950mm copper jaws compared. Heat input 11.3kW (steady state) 56.5kW (transient for 10 sec). Transient results at 10 sec. Incoming water temperature 20oC. Deflection is bending and some swelling of mid-jaw relative to edge supports at jaw ends. Provisional limits on deflection (Appendix B): 325um (steady state) and 750um (transient) if constrained to deflect away from beam. Axial (36o) Helical 1

# channels 2 1 Diam (m) .006 .008 Velocity (m/s) 3 3

Cooling

Total flow (l/min) 10 9 Jaw peak 85.5 78 Cooling channel peak 65.4 62.9

SS

Water out 34.2 34.5 Jaw peak 201 205 Cooling channel peak 119 139

Temperature (oC )

transient

Water out 43 40.3 SS 63 281 Deflection (um) transient 540 869

Notes: 1. the preferred cooling channel configuratio


Outstanding RC1 Unresolved Issues

• Jaw positioning– Acceptance of estimated deflection by CERN:281/869um– 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– Motors, cables, temperature sensors, position probes, …

• Cooling– Possible local boiling in transient condition & need for P~3 atm. H2O system– More flexible yet vacuum safe water supply for helical cooling– Vacuum safe water connection/diverter for axial cooling scheme


Other Studies Planned

• Tracking Studies: Hit maps for each of 11 IR7 collimators/beam and efficiency with 60cm C-C primaries and Cylindrical 75cm jaws which includes effect of tertiary collimators and absorbers

• FLUKA energy deposition with 60cm primaries & cylindrical 75 cm jaws Complete self consistent package of tracking, FLUKA & ANSYS results to support design choices unambiguously

• Better definition of RC1 thermal tests• Remnant & Prompt Dose Rate calculations • Engineer damage assessment mechanism into design• Thermal shock studies• Studies/experiments to verify

– assumed extent of damage in accident• Where metal slag will wind up

– acceptable peak temperature of jaw


2.5 cm

Missteered beam (9E11 protons)on secondary JawCopper

Jaw

Cross section at shower max.

Copper

Fracture temp. of copper is about 200 deg C

What is the damage area in a missteering accident?

Assumed Damage threshold seems inconsistent with FNAL experience


FY2005 Deliverables

Collimator Assembly & Test Area (SLAC-ESB)

RC1 CDR Draft9/30/05

32 pages + figures


FY2006 Work PlanNon-beam Mechanical & Thermal Performance of RC1

1. Single jaw thermal test: one jaw with internal helical cooling channels to be thermally loaded for testing the cooling effectiveness and measuring thermal deformations. – Heating by commercial electric resistance heaters coupled to the jaw with

thermal grease– Operated in a tank purged with inert gas to protect the copper jaw from

oxidation.– Flexible cooling supply that won’t be intended to allow rotation of the jaw. – A FE model of the test jaw will be used as a benchmark to evaluate the

response of the test jaw to the test conditions.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. • Lidded vacuum tank for easy access. • Cooling water feed-throughs and flexible connections as realistic as possible.

• A reasonable effort will be made to test RC1 under heat loading but this will

probably prove to be impractical.


FY 2006 Deliverables

1. Final version of RC1 CDR• Nov. 1, 2005 ?

2. External review of RC1 CDR• Nov. 14-18, 2005 ?• Dec 12-17, 2005 ?

3. Performance report on RC1– Sept.30, 2006


FY2006 Staffing

• Expect continued involvement of existing collaborators at current level• Devoted engineer

– negotiations with SLAC “Klystron” shop underway– negotiations with SLAC “Research Division” ME “shop” underway– employment requirements prepared & will be sent to:

• Fermilab, CERN, etc.

• Mercury News, etc.

• Devoted postdoc– Advertisement prepared– People coming through for a “SLAC Postdoc” interviewed

• In-house & external shop & design work as needed


Detailed FY2006 Work Plan


Inter-Lab Collaboration

• Excellent good will & cooperation limited only by busy work loads on other systems– Exchange of mechanical drawing files– Installation of latest FLUKA at SLAC– Transfer of latest mod to SixTrack– Latest hit maps with 60cm primaries

• Invaluable 3 day visit by 4 CERN staff• Monthly video meetings mostly killed April-present due to visit, other meetings, summer,

…• Next video meeting Oct 11, 2005• CERN review of SLAC draft CDR• CERN participation in RC1 CDR review

• Exchange of detailed technical information will be crucial to delivering prototypes on time

– Drawing of support structures for H, V Skew– Ideally, CERN would send old prototype parts (i.e. everything [support structure with

steppers, motors, bellows, LVDTs,…] except for the tank & cylinder jaws) rather than have SLAC re-fab from drawings or from transcriptions of drawings


Conclusion

To meet the Jan.1, 2008 RC2 ship date requirement SLAC and CERN collaborators have agreed on an initial set of specifications for the first mechanical prototype RC1– based on extensive but incomplete studies done to date– consistent with CERN beam & mechanical constraints & which

uses Phase I design to maximum extentRC1 Prototype Conceptual Design, while not 100% complete, has been

written up and serves as a start point for construction.– report to be finalized & reviewed in FY2006

Fabrication of RC1 in two main steps in FY2006, with appropriate thermal mechanical tests, should validate most of the design issues

Design extension to RC2, a beam-test-capable prototype, will occur in parallel

Good (but of course could always be better) communication and exchange of information marks collaboration between labs

100% devoted manpower required to ensure success


Status of Phase II Efficiency Studies

Excellent understanding of the code:– Tracking simulations of 1m metal secondary collimators at 7 show

inadequate efficiency (plot shown previously)– CERN provided upgraded code with absorbers & tertiary

collimators added will hopefully show adequate performance– Continue to understand playoff between gaps, lengths and

materials and provide loss maps for use as FLUKA input for suggested modifications


Vertical & Skew Collimators

Secondary halo in normalizedphase space at the end ofcollimation system

Collimators are projected to The end of collimation system

Primarycollimator

This is an independent check of the simulation code, since the collimators are plottedaccording to the lattice functions calculated using MAD.

6 and 7 sigma contours


Tertiary Halo: Particles Escaped from the Secondary Collimators

TCSG.D4L7.B1

TCSG.E5R7.B1: last skew collimator Number of particles beyond10 is 73, which is consistentwith the efficiency calculation:73/144446 = 5x10-4.

Tertiary halo at large amplitudeis generated by the large-angleCoulomb scattering in the lastcollimator.

If we add a tertiary collimatorat 8 in the same phase asthe collimator: TCSG.D4L7.B1after the secondary collimators,the efficiency should be betterthan 1x10-4.


Status of Phase II Energy Loss Studies

FLUKA with “simple” CERN-provided input file modeling ~40m around primary collimators used for all SLAC studies

Let “pencil beam” halo interact in primary vertical carbon collimator and study energy deposition in rectangular 25x80mm jaws at 10– Assume 80% inelastic int. in primary, 2.5% in each jaw of secondary– Vary jaw material & provide energy deposition grid on jaw to ANSYS

• 2.5mm x 8mm x 5cm rectangular grid, mapped onto cylinder

– Understand secondary particle content, energy & spatial distributions Use CERN provided loss maps for H,V,Skew halo with jaws at 7 and re-

calculate energy deposition gridsStudy accident case:

– Transverse extent of damaged regionLonger term goal of upgrading to current CERN input structure with much

richer description of all devices in tunnel– For the moment, ask CERN for estimates of load on “easier”

collimators

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