View
218
Download
2
Category
Tags:
Preview:
Citation preview
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 3 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 4 / 47
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.)"
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 5 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 6 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 7 / 47
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)
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 8 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 9 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 10 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 11 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 12 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 13 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 14 / 47
IR7 Collimator Layout
Beam Direction
Primary Collimators
Hard Hit Secondary Collimators
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 15 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 16 / 47
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%
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 17 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 18 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 19 / 47
Mechanical Model 2005-06-01 Used NLC Concept of Central Strongback with mid-
collimator jaw gap adjuster
beam
beam
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 20 / 47
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”
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 21 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 22 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 23 / 47
Proposed layout: 136mm diameter x 950mm long jaws, vacuum tank, jaw support mechanism and
support base derived from CERN Phase I
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 24 / 47
Vacuum tank enlarged to accommodate jaw motion. Relative location of opposing beam pipe – near interference in skew orientations 10° deviation
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 25 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 26 / 47
•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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 27 / 47
Swelling vs. bending deflectionEffect depends on jaw support scheme
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 28 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 29 / 47
Rigid round-square transition
Spring loaded fingers ground two jaws through range of motion
Jaw support & gap adjustment borrowed from CERN
RF Contact Overview
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 30 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 31 / 47
RAMP WRAPS 180o
STEP ELIMINATED
RF contact variation removes step
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 32 / 47
Clearance problems with RF contacts
Jaw Support Concept – unresolved issues interferences with RF parts
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 33 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 34 / 47
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)
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 35 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 36 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 37 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 38 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 39 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 40 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 41 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 42 / 47
FY2005 Deliverables
Collimator Assembly & Test Area (SLAC-ESB)
RC1 CDR Draft9/30/05
32 pages + figures
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 43 / 47
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.
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 44 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 45 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 46 / 47
Detailed FY2006 Work Plan
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 47 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 48 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 49 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 50 / 47
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
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 51 / 47
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.
LARP Collaboration Meeting. - 6 Oct. 2005 Phase II Secondary Collimators - T. Markiewicz Slide n° 52 / 47
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
Recommended