Optimization Objectives

Top Level Questions

• 10 MeV – Incorporate studies on operability, cost etc.• 50 MeV – More stringent beam specs

Þ Optimize 50 MeV design including beam specs & all other performance/cost metrics

Þ Solution should work for 10 MeV beam requirementsÞ What about June?

Some Prerequisites:

• Realistic and Optimal components (Standardized?)• Firm up beam specs out of Gun (as much as possible)• Outstanding benchmarking issues• Optimizer driving Track• Beam from photocathode?

Current state

• Prototypes exist in various design codes at 10 MeV (Target: March 20)

• Optimization driver extension (multiple-modules) in progress (New task)

Next

• Finalize on objectives (Target: March 20) • Take care of prerequisites (Some old, some new)• 50 MeV prototypes? (New task, partly existing)

Extended optimizer will be used to

• Refine prototypes• Look for global optimum

Structuree of the Optimization Program

Currently:

Optimizer

Instructions Config.

Astra

Needed:

Optimizer

Config.

Instructions

Astra

Module

Module

Module Module

Implementation is reasonably straightforward

Optimal Set

Optimization Objective

Beam propertiesLow bunch charge scenario High bunch charge scenario

Bunch charge 16 pc 100 pc

Rep rate 650 MHz <100 MHz

Energy 10 MeV 50 MeV

Emittance 50 m (4 RMS Norm.) 10 m (RMS Norm.)

Beam size (95%) 5 mm on target ??

Bunch length 1ps

Momentum spread 10-3

Max. beam envelope x<5 mm for E>2 MeV?

Halo/Particle loss ??

Optimization ObjectiveBeam properties

• Emittance, size, E/E, correlation, phase space parameters• Halo, particle loss Use 95% envelope etc. (Other measure for halo?)• Parameter at strategic locations / Global limits (x<5 mm for E>2 MeV?)

Transport properties Operability• 6D response matrix to determine diagnostic/tuning effectiveness

Geometry – Mainly through constraints

Components• Strength within operable range (constraint?)• Reality check• Different “species” of elements

Cost• Construction• Operation

Robustness• Error sensitivity

Need to distinguish between objective and constraint

Need other “Evaluators”

Components • Reasonable operating range of identified components• Necessary for standardized components

Geometry – Mainly through constraints

Cost - Need to formulate

Robustness - Separate study

High rightness option motivated hardware decisions (gun, 7-cell, ...) Continuation with standardized elements Realistic layout with diagnostic/control - to be translated to

quantitative design specsScope of PAC paper and how far we are from it.

High rightness option motivated hardware decisions

• Gun 200 keV•May be necessary given current optimization results• Does not impact 16 pC configuration (so far)

• 7-Cell Cavity •More efficient HOM damping• Only relevant for high brightness•Will change 16 pC configuration

• Decision is preferable before launching into next level of design detail to avoid retrofit.• Same with all other components (time to freeze into standard

ones)• Still keep several prototypes, but with specs spelled out to the

best of known optimum

Understanding operation/tuning requirements in detail Requirement on design parameters (Mij’s, ’s, ……) Requirement on physical dimensions

These are most likely the driving factors of the photo-fission design

What/Where Measure Control

BaselineBeam current Energy at 10 MeVEnergy at 50 MeVPhase at buncherPhase at SRF cavitiesOrbit (Everywhere)Phase SpaceLongitudinal phase space after buncher z:

dP/P:z:dP/P:

Longitudinal phase space at 10 MeV z:dP/P:

z:dP/P:

Transverse phase space after buncher <Xi Xj> <Xi Xj>

Transverse phase space after cpatures <Xi Xj> <Xi Xj>

Transverse phase space at 10 MeV <Xi Xj> <Xi Xj>Transverse phase space at 50 MeV <Xi Xj> <Xi Xj>TransportTransport properties – Longitudinal(<1 MeV)

Mij Mij

Transport properties – Transverse(Everywhere)

Mij Mij Cylindrical symmetry all the way?

Transport properties / Operability What to measure? What to control? Where? To What accuracy?

Operation/Tuning Scheme for the first 10 MeV

Physical Dimension?

5 FEET

Again, maybe time to incorporate such considerations into the basic layout before launching into next level detail• Avoid inoperable final design• Avoid having to redesign from scratch due to dimension

changes

What are the dimensional constraints?

Optimization Objective

• Beam propertiesLow bunch charge scenario

High bunch charge scenario

Bunch charge 16 pc 100 pcRep rate 650 MHz <100 MHz

Final Energy 10 MeV 50 MeVEmittance 30 m in 50 m out

at 10 MeV1 m in 10 m out at 50 MeV

Beam size (95%) 5 mm on targetBunch length 20 deg. 650 MHz

in20 ps in, 1ps out

Momentum spread

0.5 keV in 1E-3 at 50 MeV

Cost? Not now

Intermediate

Injection E 100 keV

• 10 MeV beam parameter specs not a challenge for the optimizer• 50 MeV specs may have to drive the design, plus other concerns