J.C. Sheppard, SLAC

Americas Region

ILC Positron TDR and R&D Meeting 1: Oxford

ILC GDE Activities Updateand

Undulator Scheme Status

J. C. Sheppard

SLAC

September 27, 2006

J.C. Sheppard, SLAC

Americas Region

December, 2005: Undulator Baseline Documentation – BCD

March, 2006: RDR Configuration: the undulator scheme

April, 2006: RDR Parts Inventory to Technical Systems for Costing July, 2006: RDR Preliminary Costing Results (the Big Secret)

August-September, 2006: Cost comparisons between undulator and conventional schemes; central Injector layouts and initial costing activities.

September, 2006 GDE Decision: Undulator Scheme and Central Injector

Undulator Scheme

ILC GDE Activities Update, to date

J.C. Sheppard, SLAC

Americas Region

September, 2006: RDR Text Outlines (N. Phinney editor)

November, 2006: Valencia Meeting: RDR Text and Costs (???? rumors of short delay with appropriate rescoping of RDR deliverables….)15 pages for undulator scheme; not clear how alternatives are being handled

Undulator Scheme

ILC GDE Activities Update, thru end of calendar 2006

J.C. Sheppard, SLAC

Americas Region

Layout of ILC Positron Source: December, 2005

e- sourcee-

DR

e- Dump Photon Dump

e+

DRAuxiliary e- Source

Photon Collimators

Optical Matching

Device

e+ pre-accelerator ~5GeV

150 GeV 100 GeV

HelicalUndulatorIn By-Pass

Line

PhotonTarget

250 GeV

Positron Linac

IP

Beam Delivery System

e- Target

Optical Matching

Device

e- Dump

Photon production at 150 GeV electron energyK=1, =1 cm, 100 m long helical undulatorTwo e+ production stations (1 as backup) + KASPulsed OMD (shielded target)Keep alive auxiliary source is e+ sideTiming Insert and Trombone in PML Extension

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Positron System Site Layout: July 2006

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Positron System Site Layout Discussions: September, 2006

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Positron System Site Layout Discussions: September, 2006Central Injector Discussions:

Electron dr and a single positron dr in a single tunnel located at the center of the ILC site

Two 14 mrad crossing angle IPs at a different elevation (~10-20 m) from dr’s

Positron production still at 150 GeV point in electron main linac

e+ transport line reduced from 18.7 km to about 5 km

Removal of timing insert (still need to do correct timing) and 2nd IP trombone

Looking at feasibility to use e- source to make 500 MeV KAS drive electron beam

Cost reductions thru hardware reduction

~30 km of low emittance, damped beam added to RTML systems

Ongoing discussions that have lives of their own

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Positron System Site Layout Discussions: September, 2006

Impact to ongoing work for ILC Undulator Scheme:

No real changes to the technical challenges

No parameter changes

Reduction of transport lines

Rework of injection/extraction schemes

Still have same technical challenges and cost drivers

Work continues

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Abstract:Detailed positron systems designs and documentation are required for the ILC TDR by the end of FY09. The goal of the research and development for the ILC positron systems is to learn enough about the component and subsystem technical requirements such that the scope of the resource requests in the TDR are adequate and not excessive. Included in the R&D list are key enabling technologies. Detailed systems integration, design, and engineering for manufacture are not considered herein. Fabrication of production prototypes is to be done as part of the construction phase of the project.

Undulator Scheme

ILC Positron System Design and R&D Goals in Support of the TDR

J.C. Sheppard, SLAC

Americas Region

R&D Tasks:UndulatorOMD/Flux ConcentratorTarget StationRemote HandlingPhoton Collimation and StopsPositron StabilizationCapture RF SystemsFast Ion Instabilities

Documentation:TDR

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: Undulator

Demonstration of undulator performance with a standard module:

Up to 200 m of helical undulator with K=1, = 1 cm, and inner diameter > 6 mm is required. The undulator is a superconducting magnet design and is made from modules which are 2-4 m in length. The goal is this task is to select a technology (Nb-Ti or Nb-Sn), specify the performance characteristics (K value, aperture, length, tolerance), build and measure the performance of a prototype magnet. A beam test may not be required.

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: OMD/Flux Concentrator

A viable OMD: pulsed/shielded and or dc/immersed:

A strong (~7T), axial magnetic field at the exit of the conversion target is required for efficient capture of positrons. The device is called the optical matching device (OMD) and serves essentially as a point to parallel focusing element. Two candidate technologies are presently under consideration: a pulsed flux concentrator and a superconducting coil. In the former case, the magnet filed rises rapidly (~5mm) from zero to full strength immediately downstream of the target. In the latter case, the coil sits upstream of the target and the field penetrates the target. It is likely that a pulsed device can be based on previous designs which need to be improved for reliability. If the issues associated with spinning the conversion target in a strong magnet field can be successfully handled, the immersion of the target in the field offers an improvement in positron capture efficiency by as much as 40% over that possible with the field profile of the flux concentrator. Because of the uncertainties in both candidates, it is recommended that both technologies be studies and developed.

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: Target Station

Rotating target assembly compatible with OMD choice: The positron conversion target is a 1 m diameter annulus which spins at

about 2000 rpm. Approximately 30 kW of average power deposited by the beam and perhaps a similar amount of power due to eddy currents from the OMD must be removed. The goal of this project is to develop a prototype water cooled, spinning target and to test the performance of the system along with a functioning OMD as chosen in task 2.

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: Remote Handling

Remote handling strategy and task descriptions:

The beam power in the ILC positron vault is in the range of 350 kW. The target and much of the downstream accelerator components and ancillary infrastructure will become activated. To facilitate maintenance and repair, it is necessary to develop remote handling techniques and systems for this area. It is likely that much of what is required can be adapted from facilities which have similar issues, such as the SNS, ISIS, various hot cell facilities, and perhaps reactor installations. It is recommended that existing remote handling facilities and techniques be studied for application and unique needs for the ILC positron vault be identified. A strategy for remote handling must be developed and a design for this capability needs to be developed and fully integrated into the positron system. A simulation of component and vault dose and activation is required.

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: Photon Stops and Collimation

Photon stops and photon collimation:

Positron polarization can be enhanced by collimating the incident gamma beam. Some designs call for cutting as much as 50% of the incident photons which corresponds to an average power of up to 175 kW. As a separate issue, it is necessary to collimate large angle gammas along the length of the undulator to prevent unwanted energy deposition along the undulator. While the power levels are reduced from that of the main photon collimator, the spectrum of the photons is similar to those absorbed by the main collimator. The goal of this research is to develop the photon collimator and photon stops, prototyping and testing as necessary.

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: Positron Stabilization

Stabilization schemes: intensity control, fault recovery:

Positron intensity fluctuations arise from variations in the drive electron beam intensity as well as due to drift and jitter in the positron system itself. The goal of this task is to identify all potential sources of intensity jitter, invent solutions and work arounds, and to develop hardware as necessary.

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: NC RF

Normal conducting structure demonstration of achievable gradient and power handling capability:

(separate presentation if time permits or will add to meeting notes)

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: Fast Ion Instability

Fast ion instability mitigation in undulator, as required:

(Expect this to be resolved in FY07; presently have a vacuum specification of 100 nTorr which is under discussion)

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Tasks: TDR Development

Positron System Design and Optimization:

Positron accelerator system design and optimization studies. The goal of this task is to produce the positron system documentation required for the ILC TDR. This goal includes complete specifications for all aspects of the positron system and full integration with the ILC.

Undulator Scheme

J.C. Sheppard, SLAC

Americas Region

Challenge:

The foregoing need better definition in terms of work packages; need to do what is required for the TDR, need to push off what can not be accomplished into construction.

Need to avoid duplication if possible

Need to run in parallel as needed

Important to develop and implement a global entrerprise

Undulator Scheme

J.C. Sheppard, SLAC

Americas RegionUndulator Scheme

FY07 FY08 Comments

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Undulator Assume K=1,=1 cm, helical

Specifications • • • • Explore parameter space

Short Sam ple • • • develop short sample

Prototype • • • • • • • • develop full length engineered module

OMD/Flux Contentrator Baseline pulsed device

Im m ersed Target Des ign • • • • • • • • • • • • eddy current simulations and test

Pulsed Flux Concentrator • • • • identify engineering issues

Prototype • • • • • • • • • demonstrate performance

Target Station 1 m dia TiAlV w heel@2000 rpm w / OMD

Engineering Des ign • • • • identify engineering issues

Target Prototype • • • • • • • • build and test

Target Tes ting • • • • • • test w / OMD w /o beam

Remote Handling Scheduled maintenance 3 m/yr

Specification • • • determine requirements

Straw Des ign • • • • develop candiate solutions

Review • • cost and ref ine

Photon Collimator and Stops Polarization enhancement, undulator vacuum

Specification • • • • decide on requirements and benef its

Des ign • • • • identify issues

Prototype as necessary • • • • as required by engineering uncertainty

FY09

J.C. Sheppard, SLAC

Americas RegionUndulator Scheme

FY07 FY08 Comments

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Positron Stabilization Improve ILC operational stability

Specification • • • • delimit problem and solutions

Develop and test as necessary • • • • modeling, simulations, component definition

Laser Compton Needs to show viability

Accelerator System Definition • • • • delimit problem and solutions

Develop and test as necessary • • • • • • • • laser and optical cavity development

Technical Design Report Due end of Q2 FY09

TDR development • • • • • • • • • • • • Q2 FY09

Start to end simulations • • • • • • • • • • • • full TDR scope, component specs, perf simu

Civil • • • • • • • • • • • • specify and review

Sys. Engr. And Design • • • • • • • • • • • • 30% Design for TDR

Coordination • • • • • • • • • • • • Overall integration

FY09