1. ILC-CR-0004 Main Linac extension: Implementation status
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
includes Change Request #6 (CR06) … IP BPM
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
~372 m to ~360 m
40 m drift space in e- system (d/s dogleg) to bypass target infrastructure
implement Change Request #4 (CR04) … extension of Main Linac tunnels
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)
includes Change Request #10 (CR10) … BC1 and BC2 part of Main Linac
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
Main Linac
BSY
DUNIT1
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

10. 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

11. 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

12. LCWS2015 : Beam Dynamics / M. Woodley
MPS collimation FF
kickers
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LCWS2015 : Beam Dynamics / M. Woodley

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

14. 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

15. From “SB2009 Proposal Document”
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LCWS2015 : Beam Dynamics / M. Woodley

16. LCWS2015 : Beam Dynamics / M. Woodley
Continuing Work
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!
investigate using MAD-X instead of MAD8
fix path length between kickers and septa in DR (127 μm + 32 μm = 159 μm error)
make identical modifications to electron systems
DR injection/extraction model
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 (same location relative to booster linac)
assume ±230 mm range (as specified in CR04) … set initially to +230 mm and readjust path lengths
don’t move booster linac or include new energy compressor yet (Change Request)
verify BSY laserwire chicane offset large enough for laserwire photon detection
old (polarimeter) chicane offset was 20 mm … offset now is 8 mm
don’t change eBSY fast abort line (requires further study)
shift all Treaty Point coordinates to restore IP to origin (0,0,0)
earth’s curvature following and vertical dispersion only if time permits
release ILC2015b in 2015 (!)
11/3/2015
LCWS2015 : Beam Dynamics / M. Woodley

17. LCWS2015 : Beam Dynamics / M. Woodley
Conclusions and Outlook
implementation of CR-0004 is about 50% complete
need to apply positron system modifications to electron systems
need to add positron path length correction chicane
need to shift coordinate system / Treaty Points to restore IP at origin (0,0,0)
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

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