ALCW15 Mike Harrison AD&I and Change Request status.

ALCW15Mike Harrison

Mike Harrison

AD&I and Change Request status

Design Considerations

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At present we have the site specific design and SRF technology development as the two broad program goals.

Design changes that have CFS ramifications are given priority

We are trying to implement design changes that improve the machine and result in cost reductions or cost neutral at worst

Not much value engineering, no DR work, no electrons

No new cost estimate on the horizon

Overall schedule uncertain

ALCW15Mike Harrison

• TDR baseline is under change management control

ILC Accelerator Design: Post-TDR Updates

Propose(Creator)

Review Decide Implement

CR-001 Add return “Dogleg” to target by-pass

2014/08/27 (K.Yokoya)

done Rejected

CR-002 Adapt equal L* for both detectors 2014/09/02 (G. White)

done Differed to Review Panel

L* to be settled to ~ 4.1 m

CR-003 Detector hall with vertical shaft access

2014/09/16 (K. Buesser)

done Accepted

CR-004 Collision point timing adjustment & tunnel extension

2014/12/18 (N. Walker)

In progress

Pipeline Cryogenic layout, tunnel X-section

Proposal Expert review Decision Documentation update

ALCW15Mike Harrison

Change requests

ALCW15Mike Harrison

CR-004: Collision point timing

The Charge…..Your charge is essentially to look at all aspects of the problem (including tolerances) and

propose a practical solution which can then be integrated into the baseline design. The key aspects are : Proposing a realistic scheme which maintains the overall IP collision timing constraint Explore any possible constraints on the allowed bunch patterns in the damping ring (flexibility) Understanding the tolerances for the required path length adjustment(s):

static - a ‘one time’ correction concept for an survey (installation) error for the path length

dynamic - dealing with ‘drifts’ (both ‘slow’ long term as well as any relatively fast corrections required)

ALCW15Mike Harrison

CR-004: The numerical condition

Length (DR ejection -> IP) – length (target -> IP) + length (target -> DR injection) = n * DR circumference

For a given DR circumference: ML length is quantized by ½ DR circumference (~1.5km)

ALCW15Mike Harrison

CR-004 proposed change

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It is proposed to extend both the electron and positron main linac tunnels by approximately 1.5 km (total machine length approximately 3 km). For the baseline the additional tunnel length will be filled with simple passive beam transport lines.

The additional tunnel length will be used to: • adjust the total beamline path length on the positron side by 2946.x

metres in order to fulfill the timing constraint imposed by the baseline method of positron production;

• Allowing for a possible increase in the length of the linacs allows some additional margin in both achievable average accelerating gradient and top-end energy reach of the machine, and significantly reduces the risk of not achieving 500 GeV cm.

The path length adjustment (i) is consistent with the existing TDR damping ring design (circumference) and bunch patterns, and while potentially not the cheapest solution, when taken together with (ii) appears to be the more straightforward approach.

ALCW15Mike Harrison

CR-004 proposed change

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The main issues with respect to CR-4 are: • Increased Tunnel Length - Increase in cost (€80M)• Additional beam transfer line w/magnets - Increase in cost

(€20M)• Relocation of horizontal access tunnels - initial review indicates a

cost neutral solution• Cryogenic system - currently unchanged from TRD design - cost

neutral• Additional access point - unlikely

ALCW15Mike Harrison

Change Request Register

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Creator Primary WGs Title Description StateN. Walker BDS / MDI Alternative FF scheme removing

strong sextupoles from FDConsider alternative FF schemes which would remove the strong sextupole magnets from the FD.

Under consideration

B. Parker BDS / MDI / CFS Reduce IR crossing angle Develop hilghly-compact SC FD to allow for smaller crossing angle.

Removed

  BDS Adopt Kamaboko-style solution for BDS / central region

Replace separate service tunnel with Kamaboko-style solution

Under consideration

N. Walker MDI Integrate laser wire(s) into IR region (detectors)

Incorporate one or more laser wire system in into the detectors ± some distance from the IP to facilitate accelerator tuning.

Under consideration

N. Solyak SRF / ML Implement cost-effective PDS Update current PDS design to a cheaper simpler alternative

Under consideration

A. Yamamoto CRYO / ML Relocate cryo components to surface

Move compressors and helium storage to surface sites (requires long transfer line).

Under consideration

M. Kuriki PS / CFS / PHYS 300-Hz e-driven source Adopt 300-Hz e-driven positron source as baseline Under consideration

? CFS Reduce the width of Kamaboko shield wall

Reduce the width of the ML tunnel shield wall in accordance with defined radiation safety protocols

Under consideration

LCB ML / CFS Implement design for energy staging.

Effectively develop lattice / CFS design for first-stage 250 GeV cm operations.

Removed

G. White BDS / MDI Move FFBK kicker downstream of QD0

Locate intra-beam FFBK downstream of QD0 (inside detector), to effectively increase FD vibration tolerance correction range.

Removed

G. White BDS / MDI Add BPM downstream of QD0 Add a BPMs immediately downstream of the QD0s to facilitate beam capture and construction of a "virtual IP BPM".

Under consideration

ALCW15Mike Harrison

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H. Hayano SRF Adopt Saclay-like tuner as baseline Adopt LCLS-2 tuner and associated helium tank and flange solution.

Under consideration

E. Paterson PS Add timing adjustment chicance system

Implement a timing adjustment chicane in the positron injection system to allow for fine path-length adjusment.

Under consideration

G. White BDS / CFS Length adjustment of BDS lattice Release of new lattice after review and subsequent development.

Under consideration

G. White BDS / CFS Include beta matching section Add a dedicated beta matching lattice section to aid tuning (similar to ATF2)

Under consideration

E. Paterson DR Modify circumference of DR Adjust circumference of damping ring to accommodate global timing constraint

Removed

N. Walker DR Add RF and wiggler for high current 10Hz operation

Configure DR designs to accommodate 100ms dampng time with 2625 bunches to allow for 10-Hz collisions after the luminosity upgrade.

Under consideration

N. Walker ML Increase bandwidth of extraction lines in BC

Review operational requirements of fast extraction lines and dumps and re-design appropriately.

Under consideration

N. Walker ML / CFS Change in average gradient specification in ML

Adjustment of baseline average accelerating gradient in the main linacs.

Under consideration

N. Walker ML Modify lattice for staged implementation

Lattice design for the first-stage 250 GeV machine. Removed

H. Yamamoto ML / CFS Extend max. energy reach Extend maximum energy range of the machine to 550 GeV centre of mass.

Under consideration

Wei Gai PS Extend undulator length to 230m as baseline

Remove need for 10-Hz production mode at 250 GeV centre-of-mass energy

Under consideration

Wei Gai PS Alternative target design Adopt alternative photon target design Under consideration

H. Hayano SRF Magnetic shield inside helium tank Place magnetic shielding inside helium tank to simplify string / cryomodule assembly.

Removed

D. Rubin DR Reduce number of BPMs Reduce the compliment of BPMs in the DR lattice Under considerationD. Rubin DR Loosen multipole tolerance specs. Update magnet specifications to reflect allowable

looser tolerances on magnet multipoles.Under consideration

ALCW15Mike Harrison

Change Request Register

CR – ?? Cryogenic Concept

From Nakai et alALCW15Mike Harrison

CR-xx Cryogenic Concept

From Nakai et alALCW15Mike Harrison

CR - ?? Tunnel X-section

From Enomoto et al

3.5 m baseline shielding wall arose from the requirement of personnel access during beam-on operations. This arose from reliability arguments including those related to the HLRF

More on Tuesday

ALCW15Mike Harrison

CR – ?? Beam Delivery System single tunnel

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SW3.5m%

PAC Paris April 2015Mike Harrison

15

Positron production remains an issue

The R&D program was suspended when the US effort was terminated post-GDE.

We had not shown a working target due to failures of the ferro-fluidic vacuum seal

ALCW15Mike Harrison

Sliding Contact Cooling Heat Transfer Demonstration – Argonne Lab proposal

Sliding Contact Cooling

2x Infrared Thermometer

250 watt halogen lamp

ALCW15Mike Harrison