NLC - The Next Linear Collider Project

NLC IP LayoutWhat’s New?

Tom Markiewicz

LC’99, Frascati, Italy

October 1999

Tom Markiewicz

NLC - The Next Linear Collider Project

Detector Reference Modelsfrom US Linear Collider Detector Collaboration

2m2m

Small detector with 6 T Solenoid Large detector with 3T Solenoid

6m6m

1.2 cm2.5 cm

4T

1.2 cm

Tom Markiewicz

NLC - The Next Linear Collider Project

IR Layout Design Philosophy

20 mrad crossing angle and L*(incoming) = 2 m

Maximize transverse space available for incoming and extraction beam optics

Maximize separation between IP and point where debris can scatter

Compact Low Mass Q1 Magnet

Extract beam outside of Q1

Deal with vibration tolerance (x/y = 235 nm/3.9 nm) without dictating detector design

Support Q1 on piezoelectric mover to adjust position

Leave space for active sensor: interferometer or inertial

L*(outgoing) = 6 m

Leave space for incoming beam optics

Conical Mask (M1): Protect detector from backscattered e+e- beam-beam pairs and SR

Minimum Angle set by Detector Solenoid Field choice

M1 tip location and thickness a detector dependent detail

Beam Pipe: r = 1 cm for 1.2 cm VXD inner layer but move away from beam ASAP

Tom Markiewicz

NLC - The Next Linear Collider Project

Small Detector IR DesignKnut Skarpaas VIII and Andy Ringwall

Detector solenoid coil relatively short, so BQ1 BIP

•OK for optics (ask PT for details)

•OK for Q1 Rare Earth Cobalt

Q2 magnets sit on extension of tunnel floor

Extraction line sits on extension of tunnel floor

Q1_SC and Q1_REC sit in cantilevered support tube

•PT trying to design away need for Q1_SC to be superconducting

•Q1_SC is OUTSIDE the detector when doors are closed

•Engineered design of Q1_REC done

•Q1_REC support scheme developed

Tom Markiewicz

NLC - The Next Linear Collider Project

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LCD Small Detector with L* =2m CD1 OpticsPlan View

M1

M2Q1 Q1-SC Q2

Q1-EXT

10 mrad

Support Tube

Lum

RF Shield-10 mrad

Tunnel Wall

Beam Pipe

Tom Markiewicz

NLC - The Next Linear Collider Project

IR Layout Details

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Q1

Extraction Beampipe

Maximum Radius of Pair Background

x-y Distribution of Pair e-,e+ at z = 2 m1 TeV, 6 Tesla Field Map

Pairs deposit ~ ½ Watt DC 109 rad/year

Plan View - 6 Tesla Detector

Pair Energy Monitor

Collar

Tom Markiewicz

NLC - The Next Linear Collider Project

Q1: Rare Earth Cobalt (REC) Sm2Co17 or Sm1Co5 Permanent Magnet•Smaller mass works better with active vibration stabilization•Compact: Not much transverse space available, want to send spent beam outside Q1•No fluids•BUT: can REC survive B|| (reduces max. pole tip field) and B (demagnetizes over time)?

•Looks OK: For small detector Bz(2m) < 3 T and Br(2m) < 500 G•Materials study planned•If a SC Shield magnet is needed, would need to rethink entire layout

Q1 SC: SuperConducting•Energy tune-ability, aperture @ 500 GeV•Self-shielded (second coil) (if IN detector)

to not affect the out-going beam•Can we engineer this SC magnet away?

Q2A & Q2B: Iron •Energy tune-ability•Outside detector•Needs to fit in transverse space allowed by crossing angle and extraction line

Q1-EXT: REC Permanent Magnet to minimize space required

Final Doublet Magnet Technology Choices

Q1

SC Solenoid Shield

Reduction in Pole Tip Field ofSm2Co17 in an External FieldFrom To Field1.1% 2.7% 1.5 Tesla8% 21% 4 Tesla20% 62% 6 Tesla

Tom Markiewicz

NLC - The Next Linear Collider Project

LC Small Detector Field Map

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versus z, NLC IR Solenoid 1

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z, m

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Br vs z along beam path, NLC IR Solenoid 1

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z, m

Br, T

L* L*

Uniform Current Density 6 Tesla Coil

Tom Markiewicz

NLC - The Next Linear Collider Project

Accommodation for •piezo actuators•sensor systems

•lines of sight for interferometric sensors•space for inertial sensors

•fast feedback electrodes and kickers•beam monitoring and physics detectors•crab cavity•vacuum flanges

Detector access issues:•Doors that open in z

•Is a clam shell geometry (open detector in x or y) possible?•Detector readout electronics and cable plant

Support for weight of masks

Assembly/De-assembly plan

Efficacy of possible support tube spanning the IP

Magnet Space Conflicts

IR Hall Conventional Facilities

Operating modes: e.g. Push-Pull detectors sharing a hall

Engineering Detailing in Progress