WP4 : Beam Line Design

Deepa Angal-Kalinin

ASTeC, Daresbury Laboratory

On behalf of WP1.1+ WP1.2 (LC-ABD1) + WP4.1 (LC-ABD2) team

LC-ABD2 Plenary Meeting, 24th September 2007, Liverpool

LC-ABD2WP4 : Beam Line Design

4.1 BDS Lattice Design and Simulations (distribution of simulations)

4.2 BDS Collimator design

LC-ABD1WP1.1 +WP1.2 + WP5.3

1.1 Lattice Design & Beam Simulations

1.2 BDS beam transport simulations (lattice design, laser wire, feedback, beam halo, collimator wakefields and electromagnetic backgrounds)

5.3 Collimation

Luis

BDS Lattice Design• Pre-technology decision

– Efforts concentrated on TESLA BDS Design• Final focus• Collimation and diagnostics• Difficulties to extract the disrupted beam at 800 GeV CM

• Post-technology decision– NLC BDS design dominated– ILC with two IRs was the baseline, no design for small IR– NLC lattice adapted for survivable collimators

• Efforts mainly concentrated on developing the small crossing angle IR and extraction line design

• Lattice optimisation study for collimation performance• Evaluation of BDS collimation depths with evolving machine

configurations and machine parameters• Development of beam diagnostics optics for laser wire• Optics support for beam tests at ESA

BDS configuration changes : First ILC workshop(Nov’04) till July’06

BDS layout configuration till July 2006

RDR BDS configuration with 1 IR 14 mrad

BDS Collimation Optics Design

• Lattice optimisation demonstrates significant improvement in collimation efficiency

• Collimation depths for different detector concepts, different L* covering all the parameter ranges of the ILC

Collimated halo before optimisation

Collimated halo after optimisation

Collimation depths : ILC reference design report

F. Jackson

Emittance Tuning Simulations• Developed a robust integrated simulation environment for analysis of

various methods of beam tuning simulations.

• Simulation structure works for both ILC and ATF2 with minimal changes.

• Investigated traditional and more novel methods of beam tuning on ILC and ATF2.

• Analysis shows viable methods can be created to remove the emittance dilution effects as seen at the IP, using only the final 5 sextupole magnets.

• Performed further investigations into the linearity of such tuning knobs, and the limits with position and field errors on the tuning magnets.

• Performed tolerance studies on both the ILC and ATF2 including the effects of trajectory correction.

J. Jones, A. Scarfe

BDSIM Development• Beamlines are built of modular accelerator components• Full simulation of EM showers• All secondaries are tracked• BDSIM was used extensively for the ILC BDS simulations. • Benchmarking tests were performed for particle tracking, electromagnetic and hadronic physics processes •The BDSIM distribution was deployed on the GRID to increase the performance Screenshot of an IR Design

in BDSIM

Full IR Geometry modelled in BDSIM

Includes a full Solenoid Field Map

I. Agapov, J. Carter, S.Malton

100W/m hands-on limit

Losses are mostly due to SR. Beam loss is very small

100W/m

Losses are due to SR and beam loss

20mrad

2mrad

Losses in ILC extraction linecalculated with

BDSIM250GeV Nominal, 0nm offset

45.8kW integr. loss

J. Carter

ATF2 extraction line ILC polarimeter chicane

LW photon

dipoles

quadrupoles

positron

electron

BPMs

LW photonLW exit port

quadrupolesdipole

beam pipewindow

BDSIM Development

Also developing an interface to PLACET, for collimator wake-field studies

Being used for background calculations, also for laser-wire signal extraction:

S.Malton, L. Deacon

Recreate ILC-like background hits on BPM

BPM1 s.e. Q = -2297

BPM2 s.e. Q = -2057

BPM3 s.e. Q = -2848

BPM4 s.e. Q = -1908

Incident beam spot

A. Hartin

• Developed a simulation of the noise on the IP feedback BPM striplines caused by secondary Electromagnetic shower products that result from beam-beam primaries striking the material inside of the inner IR region. Significant GEANT modelling.

• Simulated expected noise at ESA T488 experiment, which attempted to mimic the EM environment at ILC Christine Clarke’s talk in WP7

Laser wire : Measurement precision

NOTE: Rapid improvementwith better σy resolution

Reconstructed emittanceof one train using 5% error on σy

Assumes a 4d diagnostics sectionWith 50% random mismatch of initial optical functions

The true emittance is 0.079 m rad

The Goal: Beam Matrix Reconstruction

I. Agapov, G.Blair, M.Woodely

0 100 200 300 400 500 6000

1

2

3x 10

34

Bunch #

Lu

min

os

ity

/ c

m-2s-1

IP position FB

position scanangle scan

using luminositysignal

position (or angle) scansgain additional luminosity

IP intra-train FB performance

IP position FB

position scanangle scan

using luminositysignal

marginal luminosity gain from scans (?)

G. White

J. Lopez

End Station A Optics

• Major ILC test facility• Challenges

– Varied optics demands

– Strong bends (dispersion suppression, synchrotron radiation)

• Able to achieve small horizontal and vertical beam sizes

vertical beam size 83m for collimator wakefield tests

horizontal beam size 240m for BPM studies

F. Jackson

Luminosity loss due to wake fieldsMERLIN

A. Bungau

-1 -0.75 -0.5 -0.25 0 0.25 0.5 0.75 10.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

1.20

L/L

0

Beam Offset/ y

no Collimatos Collimators

0.00 0.05 0.10 0.15 0.20 0.25 0.301E-3

0.01

0.1

1

Lu

min

osity (

*1

03

4 cm-2

s-1

)

Beam offset (mm)

Collimators

PLACET & GUINEA-PIG

A. Toader

• Snowmass 2 mrad design unsatisfactory redesign with simpler concept aiming to be as short & economical as possible

• Assumption : other ways than the present spent-beam spectrometry & polarimetry are possible to complement pre-IP measurements

New “minimal” extraction line concept

Length ~ 300 m

dump(s): 0.5 m

3 m

QF, SF warm quad & sextQD, SD NbTi (Nb3Sn) SC

FD

3 warm bends 2 “Panofsky” quads

collimators

kickers

BHEX1

BB1,2

R. Appleby et al

The number of particles inside the laser spot ±100 µm is 44% of its number at IP

y offset (600 µm) y’ offset (12 µrad).The number of particles inside the laser spot ±100 µm is 0.1% of its number at IP.

Without detector field

With detector field

14 mrad baseline extraction optics

• To compensate the detector effect and to increase the number of particles inside the laser spot size.

• Include anti-solenoid, anti-DID (for different detector concepts)

• Include magnetic and beam errors to study the diagnostics performance and effect on beam losses at collimators

D.Toprek, R. Appleby

QD0 cryostatcold bores, 2K

QF1 cryostatcold bores, 2K

~4mz=4m z=7.3m z=9.3m z=12.5m

incoming

0.2m

Be part

Legend: pump

BPM, strip-line

flangeskicker, strip-line

valve

bellows

IR vacuum design solution Tubes are TiZrV coated

Tubes are TiZrV coated

Pumps connected to the tubes close to the cone

Beam screen with holesto avoid H2 instability

O. Malyshev ; original sketch of IR region by A.Seryi

What did we achieve in last 3 years?• Strong optics and simulation core group : BDS and extraction line lattice

design and simulations • Key role in 2 mrad design

– Comparison of this design with 20 mrad has lead to currently proposed 14 mrad design with anti-DID

• Significant contributions to start-to-end simulations Feedback• Collimation depths and optics optimisation for better collimation

efficiency• Effects of collimator wake fields on beam, simulations for ESA beam

tests WP5.3 • A complete full simulation tool BDSIM and benchmarking with other

codes• Simulations for beam diagnostics optics using laser wire• Electromagnetic backgrounds simulations • Tuning algorithms and procedures for ILC/ATF2• Optics support for ESA test experiments• Significant contributions to the RDR

Ongoing and planned studies : LC-ABD2

• Performance evaluation of 14 mrad baseline• Develop BDSIM for detailed analysis of extraction line losses and

back scattering• Develop full optics simulations of skew correction and emittance

measurement section with realistic errors• Complete study of alternative extraction schemes and document • Optimisation of collimation optics, include realistic machine and

beam errors• ATF2 : simulations and beam tests • Calculate the average pressure and pressure profiles in the BDS

and the extraction lines• Decide on the choice of material for the BDS vacuum systems• Beam line integration• Optics support for ESA (or any other test facility)

The work programme fits very well into the evolving WBS for BDS EDR

• LC-ABD team has developed a skill base within UK for BDS lattice design and simulations

• Strong collaborations with LAL, CEA, SLAC, FNAL, KEK, CERN

• Much more studies, simulations and engineering design details are planned for the EDR phase.

• Look forward to implementing and testing these studies at ATF2 and other test facilities

Summary