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, 24 th September 2007, Liverpool
Jan 06, 2016
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