Some Proposals for ILC Beam Test Facilities at FNAL

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Some Proposals for ILC Beam Test Facilities at
FNAL

• Mike Church
• ILC RD Meeting
• 4/19/06

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Where Did This Come From? -- Agenda and Attendees
for Initial Discussions on Beam Facilities
3/14/06
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5 Tiered Proposals
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Beam Test Facilities and What Can Be Learned from
Them
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Flat Beams from Photoinjector
  A0 photoinjector A0 photoinjector - comment ILC
bunch charge (nC) up to 16 3.2
bunch spacing (nsec) 1000 330
RF pulse length (ms) up to .6 new gun design required to prevent overheating and breakdown 1
pulse repetition rate (Hz) 1 requires RF upgrade to increase rep. rate 5
normalized horizontal emittance (mm-mrad) 40 (_at_ 0.5nC) 8 (DR extraction) 10 (IP)
normalized vertical emittance (mm-mrad) .4 (_at_ 0.5 nC) .02 (DR extraction) .04 (IP)
emittance ratio 100 (_at_ 0.5nC) 400 (DR extraction) 250 (IP)
RMS bunch length after bunch compression (mm) .5 (_at_1 nC)   .3
RMS momentum spread after compression () 4 (_at_1 nC) 1.1
polarized? no RD in progress -- vacuum issues may be difficult yes
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ILCTA _at_ New Muon Lab
round to flat beam transformation
(will be 3)
P. Piot
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Emittance Evolution in the ILC Main Linac

• Lattice is BCD with 1 Quadrupole per 4 Cryo
  Modules. Length of a FODO cell is 86 m. Number of
  cells is 114
• Initial Beam Energy is 15 GeV, final 250 GeV
• Initial Vertical Normalized Emittance is 20
  nmrad
• The plot shows that large emittance growth occurs
  in the first 10 FODO cells (1 km length), even
  with all steering algorithms applied (both 1-1
  steering and Dispersion Free steering applied).

Projected vertical emittance, using MATLIAR
A. Valishev
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Emittance Evolution in a Model Test Facility Linac
Projected vertical emittance, using MATLIAR

• Simple model of a Test Linac 10 FODO cells of
  ILC (1 km)
• Initial Beam Energy is 100 MeV, final energy 23
  GeV
• Initial Vertical Normalized Emittance is 20
  nmrad
• With nominal element misalignments and no
  steering applied the emittance growth of 2 orders
  of magnitude is observed

A. Valishev
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Civil Construction Issues (5 GeV linac)

• A 5 GeV linac should duplicate as much of the ILC
  infrastructure as possible
• 2 tunnel design
• identical RF and cryo distribution systems
• 1 cryoplant/service building
• large access shaft plus emergency egress paths
• vertical curvature

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Possible Location of 500m Linac Inside Tevatron
Ring
500m linac
C0 collision hall
approximate site of PD
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A Survey of e- Rings
e- Ring Energy (GeV) Circ. (m) Bunch Int. (E10) Bunches Beam Current (A)
ILC 5.0 6000 2 2820 0.451
CESR-C 5 768 1.2 40 0.03
KEKB (HER) 8 3016 6 1388 1.35
PEP-II (HER) 9 2200 4.6 1230 1.23
HERA 30 6336 3 189 0.043
VEPP-4M 6.0 366 15 2 0.04
BEPC 2.2 240 20 1 0.04
ATF 1.3 138 1 20 0.07
ALS 1.9 197 .5 320 0.390
APS 7 1104 .7 324 0.099
2 new DR proposals in progress - HERA
competing with XFEL - CESRTF conversion
starting in 2008 1.5 5.5 GeV e and e- low
emittance (3nm) up to .36A(??) competing with
CHESS
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Cross Section of HERA Magnet in Tevatron Tunnel
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HERA Tunnel and Magnets
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Possible Scheme for Positron Production and
Acceleration

• Conventional positron target
• Return beamline to front end of linac
• Two options for acceleration
• Accelerate positron bunches between electron
  bunches spaced at 308 nsec
• Use widely spaced bunches so that interleaved
  positrons/electrons is not an issue
• The point is to fill the positron ring for beam
  stability/emittance studies
• Two options for DR configuration
• Reverse polarity of magnets and circulate
  positrons in same direction as electrons
• Keep polarity the same and have duplicate
  feedback, collimators, masks, aborts, etc

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This is a Work in Progress with Many Questions
Unanswered

• Could any of these facilities be (or evolve to)
  the final thing?
• Should any of these facilities by deep
  underground? Differences in ground motion,
  temperature/humidity control, etc?
• Can (an upgraded) photoinjector satisfy
  emittance, intensity, and pulse train length
  requirements for linac and DR tests?
• cost? timeline?
• Can competing facilities do better? (CESRTF and
  HERA DR)
• Can any of these facilities have dual use --
  ie, besides ILC beam physics/technology?