O. Napoly ILC Small Angle IR Workshop 19/10/2006 1

Design Challenges of the 2 mrad Scheme

Olivier NapolyCEA/DAPNIA/SACM

Workshop on ILC Small Angle Interaction Region19-20 October 2006

O. Napoly ILC Small Angle IR Workshop 19/10/2006 2

Outline

•Luminosity at 2 mrad Crossing

•Orbit and Dispersion matching in 4 T Field

•Final Doublet Magnets

•Extraction Optics– Dipoles and Quadrupoles– Beam losses handling– Tunnel Length– Costs

•Post IP diagnostics

O. Napoly ILC Small Angle IR Workshop 19/10/2006 3

Luminosity at 2 mrad crossing-angle

Nominal Large Y Low P High L TESLA Med Q P

x nm 626.5 495 452 452 554 443

z m 300 500 200 150 300 200

L/L0 % 0.90 0.70 0.91 0.95 0.88 0.91

0

• Beam-beam effect usually increases the luminosity loss • Crab-crossing via dispersion matching will depend on E vs. z linear correlation

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Orbit and Dispersion matching in 4 T solenoid

LDC SiD GLD

S T 4 5 3

LS m 7 5.54 9

y* µm 29.4 23.0 36.5

y nm 5.7 8.1 3.8

I hope I am wrong ; 14 mrad is 7 times more !!

Single beam y* = (Dy)* = ½ (LS/2)2 (BS /2) / (B

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Final Doublet Magnets

type

SC

SC

NC

NC

NC

cf. Robert and Gian Luca ‘s discussion

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Final Quadrupole QD0 from LHC IR

QUESTIONS:• Is there an Iron yoke and do we need it ?• Field margin in LDC, SiD, and GLC solenoid (0.9 T in 2.7 T)?• Mechanical support and stability in 1 mrad angle w.r.t. B0 axis ?• Is Nb3Sn the way to go ?

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Final Sextupole SD0

QUESTIONS (same):• Is there an Iron yoke and do we need it ?• Field margin in LDC, SiD, and GLC solenoid (0.9 T in 2.7 T)?• Mechanical support and stability in 1 mrad angle w.r.t. B0 axis ?• Is Nb3Sn the way to go ?

O. Napoly ILC Small Angle IR Workshop 19/10/2006 8

Final Quadrupole QF1 and Sextupole SF1

• Assuming warm magnets, can one design them with horizontal clearance apertures, i.e. no yoke in the x > 0 half-plane ?

QF1

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Extraction diagnostics dipolesPresent design assumes 49 dipoles, 400 mm full gap, 2 m long, 0.42 T @ 250 GeV beam energy, per beam line

•18 BX dipoles for horizontal extraction , with vertical gap• 32 BY dipoles for the vertical chicanes, with horizontal gaps

300 kW per dipole at 1 TeV c.m. 30 MW total both sides.

QUESTION #1:• Do we need the large aperture all along ?The magnet power scales like the aperture and energy squared

O. Napoly ILC Small Angle IR Workshop 19/10/2006 10

Diagnostics chicane dipoles

QUESTION #2:• Do we need that many magnets ? 12 + 12 + 8 BY dipoles for the vertical chicanes with horizontal gaps0 + 8 + 4 BY dipoles are used in the 20 mrad scheme

O. Napoly ILC Small Angle IR Workshop 19/10/2006 11

Diagnostics chicanes dipoles

QUESTION #2 bis:• Do we need the extra quadripoles QEX3,QEX4,QHEX5 and dipoles BHEX2, BHEX3 ?

2 mrad post-IP diagnostics

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Extraction dipolesQUESTION #3:• Do we need BHEX5 + QEX6, QEX7 doublet ?

roughly saves 150 m tunnel

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Extraction quadripoles“the unfeasible magnets” ?

Challenges:• three useful apertures• large aperture for extracted beam• power consumption ~1 MW @ 1 TeV cm

QEX4