1. LCWS2015 : Beam Dynamics / M. Woodley
Lattice Design Update
for RTML, ML, and BDS
Tuesday, November 3, 2015, 11:35 AM, 25 minutes
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

2. LCWS2015 : Beam Dynamics / M. Woodley
Overview
the most recent “official” release of ILC lattice description files (MAD8 Extended Standard Input Format files), corresponding to the TDR, was made at ALCWS-2015 in April and designated “ILC2015a”
goals of present work:
implement Change Request #2 (CR02) … single 4.1 m L* for both detectors
merge ILC2015a FF design with T. Okugi design … FF length increased by m
include separate low and high energy COL and FF definition files
ilc661.pcolle.xsif, ilc671.pffle.xsif (ECM < 600 GeV)
ilc661.pcolhe.xsif, ilc671.pffhe.xsif (ECM > 600 GeV)
includes Change Request #6 (CR06) … IP BPM
see discussion at BDS/MDI session on Thursday
fix error in laser wire chicane length in BSYs … maintain identical e- and e+ systems
BSY length decreased by m
photon path length (undulator exit to target) decreased by m
implement Change Request #4 (CR04) … extension of Main Linac tunnels to correct global e-/e+ timing
pLET system (pDR → IP) length increased by m (after changes mentioned above)
part of length increase in pLTL, part between pBC2 and pML, the rest at the end of pML (before pMPSCOL)
path length difference (e-/e+) set to 10 x CDR
FF offset got mm bigger (old: m; new: m)
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

3. LCWS2015 : Beam Dynamics / M. Woodley
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

4. LCWS2015 : Beam Dynamics / M. Woodley
LTL to
turnaround
match
LTL
FODO
cells
DR extraction
turnaround
BC2 to
Main Linac
match
Return Line
Main Linac
Main Linac
extension IP
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

5. LCWS2015 : Beam Dynamics / M. Woodley
e+ system changes for CR04
pLTL
add 20 “RETURNCELLC” FODO cells after MARKer “M_8_cell_end”
did NOT change FODO cell length (still m cell length)
add m to “RTMATCH” beamline just upstream of turnaround
rematch return line to turnaround
pBC2
add 88.5 m to “BC2_ML_2” beamline (matching between pBC2 and pML)
rematch pBC2 to pML
pML
inserted space for an additional complete 12-string (36 ML unit) cryo unit … details to follow
pBSY
shorten laserwire chicane from 76.9 m to 42.6 m
shorten center drift from 11.5 m to 5.0 m
replace eight (8) quadrupoles used to match to FF through polarimeter chicane
old: length = 3 m, bore = 80 mm
new: length = 2 m, bore = 12 mm
rematch BSY to FF through polarimeter
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

6. LCWS2015 : Beam Dynamics / M. Woodley
LTL
turnaround
LTL FODO cells
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

7. LCWS2015 : Beam Dynamics / M. Woodley
LTL
turnaround
RTMATCH
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

8. LCWS2015 : Beam Dynamics / M. Woodley
kickers
BC2
Main Linac
BC2_ML_2
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

9. LCWS2015 : Beam Dynamics / M. Woodley
BC2_ML_2
BC2 e+
Main Linac LW
chicane
BC2
dump
line
septa
kickers
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

10. LCWS2015 : Beam Dynamics / M. Woodley
Main Linac
BSY
DUNIT1
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

11. LCWS2015 : Beam Dynamics / M. Woodley
positron Main Linac extended at downstream end (before MPS collimation)
inserted space for an additional complete 12-string (36 ML unit) cryo unit
include space for end boxes, service boxes, and warm drifts
same quadrupole center-to-center spacing as Main Linac
same cryo unit-to-unit spacing as Main Linac
replace cryogenic quadrupoles with BDS “Q75L2000” magnets
core length = 2 m, bore = 75 mm
maintain Main Linac optics (β-functions)
no additional cryomodules included (drifts, quads, BPMs, XCORs, and YCORs only)
if populated with cryomodules, would provide an additional ~30 GeV of acceleration
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

12. From “TDR lattice (2015a) review and status” (ALCW-2015)
Recreating the TDR CFS geometry
subsystems
comments
EBSY1 / EBSY2
PBSY1 / PBSY2
Redefinition errors discovered during “deck integration”:
polarimeter chicanes were copied from *BSY2 to *BSY1 as separate laserwire detection chicanes
names of elements (bends and drifts) were not changed
names of parameters that defined bend and drift lengths were not changed
values of parameters that defined bend and drift lengths were changed in *BSY1 files
when *BSY1 file is loaded, LW chicane is 45.1 m long
when *BSY2 file is loaded, LW chicane is redefined to be 76.9 m long (ΔL = 31.8 m)
TDR CFS coordinates include BSY LW chicanes that are each 31.8 m too long
PBDS was 0.95 m shorter than EBDS due to rematching between PBSY and PFFS, so:
shorten PMPSCOL by 0.95 m and rematch
modify PBSY2 such that EBDS and PBDS are now identical
redefine TDR CFS coordinates for TPML2BDS Treaty Point (e+) to be symmetric w.r.t. IP with TPS2EBDS treaty point (e-)
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

13. LCWS2015 : Beam Dynamics / M. Woodley
MPS collimation FF
kickers
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

14. From “Report of Global Timing Working Group”
EDMS number: D
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

15. From T. Okugi’s presentation at POSIPOL2015
ΔS = ±340 mm
From T. Okugi’s presentation at POSIPOL2015
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

16. From “SB2009 Proposal Document”
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

17. LCWS2015 : Beam Dynamics / M. Woodley
Ongoing Work / Issues
MAD8 SURVEY tape-file output precision (10 digit) is too small for total LET (length > 32 km) … need to use sum(Li) for μ-level precision!
path length between kickers and septa in DR (127 μm + 32 μm = 159 μm error)
still need to make identical modifications to electron systems
space for 12-string (36 ML unit) cryo unit in eML
FODO cells in eLTL
add path length adjustment chicane in e+ source system?
Okugi-san’s chicane after booster linac (smaller emittance … easier magnets)
move e+ booster linac? new e+ energy compressor? warm spin rotator solenoids?
BSY laserwire chicane offset large enough for laserwire photon detection?
present design “inherited” (post-SB2009)
old (polarimeter) chicane offset was 20 mm … offset now is 8 mm
should we change pBSY dump line to simple DC tuneup line (with reduced bandwidth)?
need to fix earth’s curvature following and vertical dispersion compensation after changes
coordinate system
IP no longer at origin of coordinate system (X = mm) … shift coordinates?
is our Cartesian system appropriate for a machine that follows the earth’s curvature?
finalize ILC2015b release
merge repository into EDMS and document
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

18. LCWS2015 : Beam Dynamics / M. Woodley
Conclusions and Outlook
unfortunately, ILC2015b MAD deck release is not ready yet
need to apply positron system modifications to electron systems
BSY issues/questions
positron path length correction chicane
coordinate system / Treaty Points
still hoping to finish in 2015!
e+/e- path lengths now differ by exactly 10 x CDR (within 1 μm)
there are sub-millimeter path length errors in DR Injection/Extraction layout to fix
all changes (such as they are) will be available from the Lattice Repository (from the “dev” branch)
ILC2015b to be next release
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

19. LCWS2015 : Beam Dynamics / M. Woodley
End
Thanks!
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

20. LCWS2015 : Beam Dynamics / M. Woodley
ILC2015b:
e+ Treaty Points
Actual MAD8 SURVEY output:
UPT (undulator end to e+ production target)
pSource (e + production target to DR injection septa)
pLET (DR extraction septa to post-IP dump)
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

21. LCWS2015 : Beam Dynamics / M. Woodley
e+ Treaty Point Coordinates
Treaty Point
Description S X Y Z
Yaw m
rad
TEUND2PTGT
end of e- undulator
TPTGT
e+ production target
TPTGT2CAP
start of e+ capture
TPCAP2PPA
start of e+ pre-acceleration
TPPA2TRANL
start of e+ low energy transport
TPTRANL2BSTR
start of e+ booster linac
TPBSTR2TRANH
start of e+ high energy transport
TPTRANH2LTR
start of e+ LTR
TPS2DR
pSource/pDR interface
TPDRISEPT
end of pDR injection septa
TPDRINJ
end of pDR injection kicker chain
TPDR
center of pDR Inj/Ext straight
TPDREXT
start of pDR extraction kicker chain
TPDRXSEPT
start of pDR extraction septa
TPDR2RTML
pDR/pRTML interface
TPRTL2LTL
start of e+ getaway
TPLTL2TURN
start of e+ turnaround
TPTURN2SPIN
start of e+ spin rotation
TPSPIN2BC1
start of e+ bunch compressor #1
TPBC12BC2
start of e+ bunch compressor #2
TPRTML2ML
start of e+ Main Linac
TPML2MPSCOL
start of e+ MPS collimation
TPML2BDS
pML/pBDS interface
TPBDS2FF
end of e+ BSY; start of e+ FF
TPIP
Interaction Point
NOT CORRECT
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

22. LCWS2015 : Beam Dynamics / M. Woodley
e+ Treaty Point Twiss parameters
Treaty Point
Description X Y β α η η’ m
TEUND2PTGT
end of e- undulator
TPTGT2CAP
start of e+ capture
TPCAP2PPA
start of e+ pre-acceleration
TPPA2TRANL
start of e+ low energy transport
TPTRANL2BSTR
start of e+ booster linac
TPBSTR2TRANH
start of e+ high energy transport
TPTRANH2LTR
start of e+ LTR
TPS2DR
pSource/pDR interface
TPDRISEPT
start of pDR injection septa
TPDRINJ
end of pDR injection kicker chain
TPDR
center of pDR Inj/Ext straight
TPDREXT
start of pDR extraction kicker chain
TPDRXSEPT
end of pDR extraction septa
TPDR2RTML
pDR/pRTML interface
TPRTL2LTL
start of e+ “getaway”
TPLTL2TURN
start of e+ turnaround
TPTURN2SPIN
start of e+ spin rotation
TPSPIN2BC1
start of e+ bunch compressor #1
TPBC12BC2
start of e+ bunch compressor #2
TPRTML2ML
start of e+ Main Linac
TPML2MPSCOL
start of e+ MPS collimation
TPML2BDS
pML/pBDS interface
TPBDS2FF
start of e+ Final Focus
TPIP
Interaction Point
NOT UPDATED
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

23. LCWS2015 : Beam Dynamics / M. Woodley
ILC2015b:
Lattice Repository
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

24. LCWS2015 : Beam Dynamics / M. Woodley
downloads
no account (user ID, password) required to download
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

25. LCWS2015 : Beam Dynamics / M. Woodley
download the
main branch
(complete set of
ILC MAD input files)
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

26. LCWS2015 : Beam Dynamics / M. Woodley
Software Management of ILC Lattice Repository
Repository (GIT) branches with access control and actions governed by branch type. Master repository hosted at Bitbucket site, with documentation etc. on co-hosted wiki. User base and privileges managed by master repository web site.
Master branch
World read access
Write access by “repository manager” only
Should correspond to currently accepted ILC “baseline” designs
Only merge-able with “release candidate” or “hotfix” branches
Hotfix & Release Candidate Branches
Read/write access only by “core development team” or users designated by these
Apply fixes or prepare releases, including applying unit test procedures to ensure e.g. Twiss parameters correct and representative beams track to give conditions specified in interface documents.
Final merge done with master branch by “repository manager” and tagged with a release code and changes fully documented and checked with EDMS document procedures etc.
Development branch
read/write by “core development team” and invited users (including CR branch managers)
Change Request Branch
Generated by “repository manager” for approved change requests and control handed over to required users as designated by the ILC CR process.
Merges in to development branch upon completion and sign-off of CR process.
Feature Addition Branch
As above, but generated and controlled for management purposes by “core development team”.
R2015a
R2015b
R2016a
CR-i
CR-j
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley