nb-ti options for lhc ir upgrade

Nb-Ti Options for LHC IR Upgrade

PAF meeting; April 2007 1

Nb-Ti options for an LHC IR upgrade have been studied since 2004:- main motivation was to introduce operation margins for the nominal / ultimate LHC operation- provide an alternative solutions for the US Nb3Sn proposal (technology / feasibility)

* = 0.25m & ultimate intensities could provide L = 4 1034cm-2sec-1

Main challenges for a Nb-Ti solution:

-radiation protection: Nb-Ti lifetime = 700 fb-1

L = 4 1034cm-2sec-1 350 fb-1 / year 2 year operation only?-Heat deposition and magnet cooling in long triplet assemblymagnetic TAS option discussed since WAMDO 2002-limited peak field

New CNI proposal provides official mandate for Nb-Ti studies at CERN

Phased LHC IR Upgrade Plan


Phase I:

Increase operation margins for the LHC as fast as possible in order to achieve nominal performance in an efficient operation mode: Provide more aperture margins in the LHC triplet magnets. Use the existing LHC magnet cables and tooling where possible. Prepare a solution that can be installed in a relatively short

shutdown by 2011. Natural evolution of the LUMI’05 and LUMI’06 discussions The Phase I upgrade aims at a peak luminosity of

L = 1-4 1034cm-2sec-1

It does not replace the previously discussed ‘ambitious’ upgrade for

a peak luminosity increase of one order of magnitude!



Phase I:

Main milestones (Lyn Evans): Develop short Nb-Ti magnet prototype by middle 2009. Full length prototype by 2010. Requires that detailed optics and layout designs are finished

by 2007. Requires that detailed Dynamic Aperture, field quality specification

and corrector package definition heat deposition studies are finished

by 2008.



Phase II

Identify new IR layouts and magnet technologies that allow a ten fold increase in the nominal LHC luminosity:

Prepare a solution that can withstand the radiation for operation with L = 1035 cm-2 sec-1

The Phase II upgrade should be implemented once the Phase I solution reaches the end of the magnet lifetime (700 fb-1 for Nb-Ti) after 2 to 3 years of the Phase I upgrade operation assuming the upgrade operation reaches L = 3 1034cm-2sec-1

earliest installation by 2015

Nominal LHC IR LayoutIR consists of DS, MS, D1-D2, Triplet:

Oliver Brüning 5PAF meeting, April 2007

D1 Q3 Q2 Q1 Q1 Q2 Q3 D1IP

2 x 23 m35 m 35 m

13 long range interactionsca. 10 long range interactions ca. 10 long range interactions

24 m 24 m

Phase 1 Upgrade Options


There are currently 4 proposals for a Nb-Ti based IR upgrade, eachbased on a different driving design criteria:

‘Compact Low Gradient’ IR design:

optimized for compactness and maximum aperture margin

‘Modular Low Gradient’ IR design:

optimized for simple spare magnet policy and magnet production

(1 magnet type only)

‘Minimum -max’:

optimized for minimum peak -function inside the final focus system

(minimization of the chromatic aberrations)

Scaled Nb-Ti solution:

Parameter choice based on optics and magnet scaling laws

‘Compact Low Gradient’ IR Design4 functional magnet elements:

Oliver Brüning 7

provide 2 parameters for -max control and 2 for controlling -functions in Matching Section

controlling -function in MS facilitates dispersion matching longer triplet section increases number of long range collisions

PAF meeting, April 2007

D1 QX3 QX2b QX2a QX1 QX1 QX2a QX2b QX3 D1 IP

2 x 23 m68 m

nominal LHC layout value ca. 25 long range interactions

68 m

max = 17.2km = 2.94mm 23 margin

PAF meeting, April 2007 Oliver Brüning 8

-choice of specialized magnet modules QX1: 12.24m, 91.5T/m 86.5mm min aperture; QX2a: 14.2m, 68.3T/m 111mm min aperture;

QX2b: 11m, 68.3T/m 111mm min aperture;QX3: 14.75m, 68.3T/m 111mm min aperture;

-implement standard inter module space

1m for inter-connect and corrector elements total ‘Triplet’ length = 60 m (31m)

‘Compact Low Gradient’ IR Design

‘Compact Low Gradient’ IR Design


Main benefits provides potential aperture margins of 23 for 6.5T peak field at coil

what is the maximum attainable peak field for Nb-Ti?

what is the maximum attainable coil diameter for Nb-Ti?

future studies require the following additional studies:

-specification of field quality tolerances and required corrector packages

-calculation of the heat and radiation deposition and identification of

potential locations for dedicated absorber masks

-specification of the maximum acceptable chromatic aberration

Main drawbacks

it requires specialized magnet types and features large chromatic aberrations

‘Modular Low Gradient’ IR Design4 functional magnet elements:


D1 QX4 QX3 QX2 QX1 QX1 QX2 QX3 QX4 D1IP

2 x 23 m75 m (35)

ca. 27 long range interactions ca. 27 long range interactions

75 m (35)

nominal LHC layout value

provide 2 parameters for -max control and 2 for controlling -functions in Matching Section

controlling -function in MS facilitates dispersion matching longer triplet section increases number of long range collisions

max = 14.4km = 2.69mm 13 / (1 margin


-2 magnet modules: 4.8m long with 2 gradients: QX1: 2 modules, 116T/m 82mm min aperture; QX2a: 4 modules, 88.5T/m 110mm min aperture;

QX2b: 4 modules, 88.5T/m 110mm min aperture;QX3: 2 modules, 88.5T/m 110mm min aperture;


1m for inter-connect and corrector elements total ‘Triplet’ length = 75 m (31m)

‘Modular Low Gradient’ IR Design

‘Modular Low Gradient’ IR Design


Main benefits provides potential aperture margins of 13 for 6.5T peak field at coil

simplified spare magnet policy (only two magnet types and 1 length)

features slightly smaller chromatic aberrations





-specification of the maximum acceptable chromatic aberration

Main drawbacks

it requires specialized powering for each unit

it offers reduced aperture margins compared to compact design

‘Minimum -max’ & ‘Scaled’ IR Design3 functional magnet elements:


D1 QX3 QX2 QX1 QX1QX2 QX3 D1IP

2 x 24 m40 m (35)

ca. 15 long range interactions ca. 15 long range interactions

40 m (35)


-choice of standard magnet module for each unit QX1: 1 module 7.5m, 168 T/m, 76mm min aperture QX2: 3 modules 5.75m, 122T/m, 105mm min aperture QX3: 3 modules 4.9m, 122T/m, 105mm min aperture;


1m for inter-connect and corrector elements total ‘Triplet’ length = 40 m

‘Minimum -max’ & ‘Scaled’ IR Design

max = 12.2km = 2.47mm no aperture margin

‘Minimum -max’ & ‘Scaled’ IR Design


Main benefits smaller peak -functions and thus smaller chromatic aberrations





Main drawbacks

it requires specialized magnet types and powering for each unit

it no longer offers aperture margins for * = 0.25m and a peak field of 6.5T

Phase 1 Upgrade Study Needs


Summary of the available information for the Phase 1 optionsStudies / Option ‘Compact’ ‘Modular’ ‘Low -max’ ‘Scaled’

magnet parameters yes yes yes yes

Coil design no no no yes

optics Beam1 Beam1 Beam1 & Beam2 no

Q’ & Q’’ correction yes yes yes -

Tunability study no no no -

Corrector package definition no no no -

Tracking studies no no no -

Energy deposition no no no -

General Upgrade Study Needs


There are several R&D needs common to all options

TAS absorber modifications (aperture) / upgrade (efficiency).

D1 dipole magnet design (aperture and reduced distance to D2).

D2 dipole magnet design (reduced distance to D1).

Potential need / benefit for upgrading some matching section quadrupole

magnets (e.g. an additional MQM module for Q6).

Triplet orbit corrector magnets need to be specified and designed.

Triplet coupling and non-linear corrector elements need to be specified

and designed.

Cooling system for the final focus and D1 magnets.

Tertiary collimators and their impact on the machine protection and

collimation system need to be studied



Required studies that go beyond new IR design:

An efficient and reliable LHC operation above nominal beam

intensities requires additional consolidation of some key accelerator

components:

Phase 2 collimation system.

Replacement of LINAC2 (-> LINAC4) .

Replacement of the PS and its power converter (-> PS2).

Upgrade of the SPS.

All the above studies are part of the CERN ‘White Paper’. The

LINAC4 preparatory studies are part of the CARE FP6 studies and

the LHC Phase 2 collimation system is already part of USLARP



There are important upgrade options that could be beneficial for both LHC IR upgrade Phases (see LUMI’06): Long range beam-beam wire compensation.

Electron lenses for head-on beam-beam compensation.

CRAB cavities and CRAB waist operation.

Studies related to a more efficient TAS absorber and triplet

magnet protection.

Studies related to the suppression of the electron cloud effect.

Upgrade studies for the LHC injector complex.

Studies related to understanding the beam-beam effects and limits.

Studies related to understanding limits imposed by chromatic aberrations

All the above options should be studied for both upgrade Phases!

General comments on collaboration needs


(e.g. studies related to the magnetic TAS option and the optics design studies at LUMI’05 and LUMI’06)

Efficient coordination:

Meeting the ambitious milestones for the two upgrade phases requires an efficient coordination of the R&D activities and the beam dynamic and optics studies within CERN and USLARP

Past experience has shown that one or two meetings on a yearly

basis (WAMDO and LHC LUMI workshops) might not be

sufficient for the timescale of the Phase 1 upgrade!

A clear definition of work packages and their priorities and milestones would be desirable

Potential USLARP Contributions


Studies specifically beneficial for Phase 1 upgrade studies:

-all optics studies are expected to be finalized at CERN by this

summer

-USLARP contributions could include:

tracking studies and field quality specification for ‘Compact’ option

specification of the required corrector packages for the ‘Compact’

option

energy deposition studies for all options

study of the required TAS and TAN modifications

Study and design of new D1 and D2 separation dipole magnets

Potential USLARP Contributions


Studies specifically beneficial for Phase 2 upgrade studies:

-Optics studies for the 25ns option are expected to be finalized at

CERN by this summer.

-USLARP contributions could include:

slim magnet design for a D0

slim quadrupole doublet design

energy deposition studies for all options

study of the required TAS and TAN modifications

nb-ti options for lhc ir upgrade

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