WHY LEIR

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WHY LEIR?
But also HOW!

• Michel CHANEL

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LHC NEEDS

• LEAD ions
• At 2.7 TeV/n, L1027 cm-2s-1 limited by central
  detector and by magnet quenches (note stot437
  barns-e.m.d.,e-capt., hadronic-, shadronic8
  barns !!!)
• Luminosity is obtained by about 600 bunches, 7
  107 ions/bunch, e1.5mm and b0.5m
• ALICE
• ATLAS
• CMS
• http//documents.cern.ch/AGE/current/fullAgenda.ph
  p?idaa021004

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(No Transcript)
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GENERAL SCHEME
LHC.LEAD.new.PUB
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BEAM PARAMETERS

• Overall efficiency 30
• LHC et1.5mm, el1eVs/Q
• SPS extraction et1.2mm, el0.39 eVs/n
• SPS injection after stripping (4 pairs of
  bunchlets) et1.0mm, el0.025 eVs/n/bunchlet
• PS injection(2 bunches) et0.7 mm, el0.05
  eVs/n/bunch

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LINAC3
Charles Hill, Detlef Kuchler

• ECR source improved from 100mA to 200mA (Lead
  27, pulse length 450ms where LEIR uses 200ms)
  by increased RF from 14GHz to 18GHz and mag.
  field accordingly as current is prop. to f2
• LINAC3 (rfq 3 IH Tank) 4.2 MeV/n, b0.094, up to
  5Hz

Collaboration Catania, Grenobles, Cern, GSI
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LINAC3
Mauricio Vretenar, Hans Broere

• Stripping, use of Lead54,
• Quads and correction dipoles pulsing at 5Hz,
• Momentum ramping for LEIR injection (0.4 in
  60ms min., 100MHz, 130kV, 2.5kW)

Energy ramping cavity
tank3
debuncher
stripper
Filter line
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M. Vretenar
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TRANSFER LINE
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TRANSFER LINE
C.Carli, J.Y. Hemery

• All laminated magnets needed have been found at
  CERN, except one(core)economy
• Quad power supplies not changing polarity between
  inj./eject. ..economy

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LEIR

• Combined H/V/P multiturn injection inclined
  septum momentum increase of incoming beam such
  the injection orbit (D dp/pdecreasing bump)
  remains the same during injection. 50 injection
  efficiency reachable(75 on paper). Recuperate
  magnetic septum, bumpers.
• Cool and stack the freshly injected beam by
  electron cooling in 400 ms max.
• 4 injection-cooling-stacking cycles should be
  enough (timelt1.6s).
• Acceleration and ejection (h2) at T72MeV/n
  energy choice is a compromise between the limit
  of incoherent tune shift in PS, the time between
  bunches for the ejection kicker, the min RF
  frequency in PS and the stacking time in SPS/LHC.

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INJECTION
D.Möhl, S.Maury, C.Carli, M.Chanel

• Combined injection gives lower et (better cooling
  time) compared to normal multiturn but increases
  mom. spread (good long. cool.).
• Combined injection implies large D and D/??h
  5m1/2 (D10, bh3).

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Injection septa
Jan Borburgh, Mike Hourican
existing
http//carli.home.cern.ch/carli/PILandLEIR/Min_02_
11_15/Septa_Inj_02_11_15.pdf
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INJECTION BUMPERS
Tony Fowler
existing
http//carli.home.cern.ch/carli/PILandLEIR/Min_02_
11_15/LEIR_Bumpers_02_11_15.pdf
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Cooling and Stacking

• Electron cooling theory gives

• where q is the relative difference in angle
  between the ions and electrons qi?(?/?)
• the parameter hecool Lcooler/Lmachine
• and Ie is the electron current.
• A and Q atom mass and charge state

• Large b desirable but ion beam size should remain
  smaller then e-beam size and mind the effect of
  the e-beam space charge. optimum around b5m
• With D0, stack and injected beam are in the
  centre of the e-beam, but this is not the best
  value for cooling.

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Cooling and Stacking

• Loss rate(LR) due to recombination between
  electrons and well cooled ions is
• To limit LR and also have a good cooling
• Low electron density on stack (e-beam center)
• High electron density elsewhere for large
  amplitude ions

http//carli.home.cern.ch/carli/PILandLEIR/Min_02_
06_27/CoolingPrinc_02_06_27.html
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ELECTRON COOLER
J. Bosser, G. Tranquille
http//carli.home.cern.ch/carli/PILandLEIR/Min_02_
06_27/CoolerHardWare_02_06_27.pdf
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ELECTRON COOLER
V. Parkomchukal
gun
collector
3m drift tube
toroids
H,V dipoles
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ELECTRON COOLER
V. Parkomchukal
preliminary
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ELECTRON COOLER
V. Parkomchukal
stack
Current density, A/cm2
Ec0
Injected beam
Ec100 V
Ec300 V
preliminary
http//accelconf.web.cern.ch/AccelConf/e02/PAPERS/
WEPRI049.pdf
Radius, mm
Calculation
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LEIR LATTICE
C. Carli
doublet
90 deg. bending
triplet
Injection
bhbv 5m, D0
D10m
bh3m, bv4m
Ecooler,ejection

• still 2 periods , tune(1.8,2.7) ,long.
  acceptance reduced to dp/p 1
• 5 quad families, more flexibility.

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extraction
RF
injection
Magnets and most of the Power Supplies are
recuperated
ecooler
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VACUUM
E. Mahner al

• During the tests in 1997, the static Lear vacuum
  was good (5E-12T without beam) but the lost lead
  ions (e-ion recombination..lead 54 or res. gas
  charge exchange or..) degas the chamber walls.
  One lead ion releases 105 molecules!!!!
• At end of linac3, tests of different vacuum
  chamber have been done which confirms the high
  outgassing rate and the desorption of CO, CO2,
  CH4 molecules.
• When ions are lost perpendicularly to walls,
  outgassing is decreased, Then organise the losses
  on collimators when possible.
• Beam scrubbing is effective
• More pumping speed
• The goal is to obtained an overall life time of
  15 sec (half due to vacuum only and half due to
  RR in ecool)

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Cycle for LEAD IONS
extraction
Acceleration
cooling
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LEIR RF
R. Garoby al

• 2 RF cavities using Finemet giving 4kV each,
  built in collaboration with KEK
• Large swing in frequency but high impedance, Very
  short

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EJECTION
C. Carli, M. Chanel

• Fast extraction of the two bunches (kick, bump,
  pulsed septum)

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EJECTION
K.D. Metzmacher, L. Sermeusal
I.Borburgh, M. Houricanal

• Kicker 2 modules 6mrad each(8max..80 kV) 120ns
  rise time (1..99)
• Pulsed septum 35kA, 5ms half wave,400ms flattop,
  gap 50mm

Existing kickers magnet
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Extraction line to PS
C. Carli,JY Hemery
LEIR
PS
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And all the other systems

• New active feedback system (BW 100MHZ)
• New power supplies for main bending and quads
• New controls
• most of the instrumentation hardware is
  recuperated, some electronics are new.

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PS

• Mind to the space charge at injection
  (DQinc-0.25)
• Inject (change septum-modif. Kicker pulser) and
  accelerate on h16 up to bg23.76
• h16?14?12, split 2b. to 4 bunches and finally
  h24 ?21
• h21 is chosen to have 100ns b. separation at
  flatop in LHC and it is compatible at 6.0 GeV/n
  with 200MHz RF system in SPS.
• Acceleration to 6.0 GeV/n(g7.45), cp/Q26.
  GeV/c/charge, to limit space charge and IBS at
  the injection flat bottom.
• Splitting the 4 bunches in 4 pairs of bunchlets
• Stripping in TT2. Change of TT2 line to have a
  low beta at stripper.

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PLANNING
J. Montero
LEIR
PS
SPS
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PM
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CONCLUSIONS

• Project on its way
• We enter in the phase of the detailed definition
  of hardware
• Everybody knows that economy is essential

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PHOTO OF THE LINAC3
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ANIMATED INJECTION
M Chanel

• Bump 60mm-0.6mm/turn, 70turns injected
  (efficiency. 80), 105 turns shown, dp/p from
  0.1 to 0.3, stack at 0.2

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injection

• x and y and momentum projected distributions of
  the injected beam

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E. Mahner al
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E. Mahner al
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A nice cavity in HIMAC (Japan)
C. Rossial
To the courtesy of M. Paoluzzi
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RF in PS
S. Hancok
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Transfer line to SPS(TT2)
M. Martini

• At stripper bh,v20m?5m, D-1m
• Blow-up reduced by a factor 4 compared to
  old(normal)optic.needs MD for SPS matching.
  De0.2mm after re-matching in SPS?.
• Need of 4 quads, 6 power supplies.(mostly
  recuperated)