LHCI Injector Accelerator for the LHC Motivation

1
LHCI Injector Accelerator for the LHC Motivation

• Inject 1.5 TeV proton beams to LHC instead of
  the current
• 0.45 TeV beams from the SPS
• At this new energy the field harmonics 1 of
  the LHC magnets are
• satisfactory enough to prevent luminosity
  losses expected with the
• lower energy of the SPS beams
• In a long term, the LHCI accelerator would
  greatly facilitate the
• implementation of the doubling of the LHC
  energy (LHC2)
• The proposed new LHC injection scheme is
  motivated by desire to
• advance goals and extend frontiers of
  high-energy particle physics
• 1 LHC Design Report Vol 1, O.Brunning et
  al., CERN-2004-003, Section 4.7 Dynamic aperture
  

2
LHCI Proposal Brief History

• Lucio Rossi of CERN proposed (9/05) to
  consider an Injector Accelerator (LHCI) based on
  the VLHC low field magnets to boost the initial
  energy of the proton beam in LHC
• HP with help from Gijs de Rijk (CERN)
  investigated feasibility of the LHCI ring in the
  LHC tunnel during 3 weeks stay at CERN in 10/05,
  and produced a report indicating that the LHCI
  magnet ring can be installed in the LHC tunnel
  but the beam injection from the LHCI to LHC is a
  very difficult problem
• John Johnstone and Tanaji Sen (11/05) begun
  investigating the
• LHCI lattice and the design of the transfer
  lines
• From 11/05 HP is discussing with Vl.
  Kashikhin options for fast kicker magnets, and
  with Steve Hays matching power supplies

3
Elected Boundaries for LHCI Injector Accelerator
Design

• - LHCI will fit inside the LHC tunnel without
  major modifications
• - LHCI magnet ring will be installed using
  regular LHC shutdowns
• - The current SPS-LHC injection scheme will
  remain intact, and
• it will be used to inject beams to the LHCI
• - A reversal to the standard SPS-LHC injection
  scheme will be possible at any time after
  implementation of the LHCI
• - The LHCI accelerator components will be
  designed using
• primarily known technologies, so only the
  prototyping will
• be necessary thus allowing to proceed with
  LHCI design now

4
Proposed LHCI LHC Injection Scheme
The new injection scheme shows only the path
from SPS to LHCI to LHC
5
VLHC Low Field Magnet for the LHCI
VLHC - 233 km accelerator
ring - 3200 main arc dipoles
- 466 km continued length of
transmission line
superconductor LHCI - 27 km
accelerator ring - 1232 main arc
dipoles - 54 km continued length
of transmission line
superconductor
6
Base Magnet of the LHCI Accelerator
We propose that LHCI is based on the VLHC Low
Field magnet

• Magnet cross-section area
• 26 cm (height) x 24 cm (width)
• 1.8 Tesla field (nominal operation)
• 0.6 Tesla (beam injection)
• 20 mm magnet pole gap
• Energized by 100 kA, single turn
• transmission line superconductor
• Coolant supercritical helium
• (4.2 K, 4 bar, 60 g/s)
• Warm beam pipe vacuum system
• (ante-chambers required)
• Alternating gradient 16 m

7
LHCI Magnet Location in the LHC Tunnel

• It fits easily in the space above the
• LHC magnet
• Minimum vertical distance between
• LHC and LHCI beams 1100 mm
• The holding brackets and the magnets
• can be installed without disturbing the
• LHC operations
• The LHe can be tapped at convenient
• locations from the QRL line (1600 g/s)

8
LHCI Arc Dipole Magnet in LHC Tunnel
Normal tunnel area
Area with cryogenic feed tower
9
VLHC Low Field Magnet Tests

• Test gradient dipole magnet -
• 1.5 m long
• Transmission line
• superconductor 16 m long
• Current leads 100 kA (RT-gtLHe)
• Power supply 100 kA dc
• Quench detection
• protection system standard
• Magnetic measurements
• - Tangential coil
• 0.7 m long, 15 mm diameter
• - 102 element Hall Array
• Supporting cryogenics
• - Two phase LHe at 5 K
• - Three independent flows of
• 6 g/s each

10
100 kA dc Power Supply

• Steven Hays MOA04P001
• 1.5 V _at_ 100 kA Switcher Power
• Supply was used as both
• - Ramping supply, and
• - Holding supply
• It consists of
• - Bulk 400 V, 240 kW filtered
• and regulated supply
• - 10 switcher cells connected
• in parallel at the input to the
• magnet current leads
• Operated as constant power device
• No regulation was available for using the load
  current, or magnetic field

11
100 kA dc Current Leads

• Yuenian Huang WEA03PO04
• Lead 202 Cu rods, 1650 mm long,
• 6.35 mm dia.
• Est. heat transfer 200 W/m2_K
• Temperature profiles
• Blue dots no current
• Purple square 90 kA, stable
• Red triangles 100 kA, 5.6 g/s,
• stable for 15

12
Magnet and B-field Measuring Instrumentation
Magnet view (Hall station side)

• Magnet view (tangential coil side)

13
Magnetic Measurements
Gueorgui Velev, TUA07PO02
Probe 15.2 mm dia. x 754.1 mm long Vespel
(polyimide) used to form the probe (winding
support) and bearings. Field Harmonics measured
to order 10 at 1.966 Tesla (collisions), and
order 6 at 0.1 Tesla (injection)
14
Magnetic Measurements

• Quadrupole component is as designed -415
  units, both at
• injection and full field 1.966 T.
• 102 element Hall Probe confirms
• the /- 4 gradient.
• Sextupole component very small
• few units, and no change from
• injection to the full field 1.966 T.
• The b4 b10, and the a4 a10
• also ltlt 4 units, or ltlt 0.04.

15
VLHC Low Field Magnet Team
Members of the VLHC Low Field Magnet Group Ruben
Carcagno, Brad Claypool, George W. Foster, Steven
Hays, Yuenian Huang, Vladimir Kashikhin, Ernest
Malamud, Peter Mazur, Roger Nehring, Andrew
Oleck, Henryk Piekarz, Roger Rabehl, Phil
Schlabach, Cosmore Sylvester, George Velev, James
Volk (FNAL) and Masayoshi Wake (KEK)
Five papers published at
MT-19, Genoa, Italy, 2005
16
Principle of the LHCI-LHC Beam Transfer

• After the LHCI ring filling is complete, the
  kicker magnets are turned
• off as soon as the last proton bunch passed
  through them.

17
LHCI-LHC Transfer Line Boundaries

• LHC-LHCI vertical separation 1100 mm
• LHC beams separation 194 mm ( LHCI 150 mm)
• Total length of ½ of straight section 260 m
• Total available free space between D1 and Q7
  176.5 m

18
LHCI Beam Pipe Inside the LHC Magnets

• LHCI beam pipes can be inside
• the LHC magnet cryostat. This
• allows to minimize to 170 mm
• the required LHCI beam
• deflection in the Kickers
• The fringe B-field outside the
• yoke is very small , and so is
• the heat load of the LHCI pipe
• Modification of LHC magnets
• can be done using the spares,
• and then swapping them with
• those in the tunnel

19
Fast Kicker Magnets
A
B

• A conceptual view of the fast kicker magnet
  arrangements
• - LHCI and LHC beam share the beam pipe
• - LHCI and LHC beams are separated

20
Fast Kicker Magnet Power Supply

• Magnet gap 6 cm gt 4 T, 90 kA, 30 KV _at_ 3
  usec 1 uHenry

21
Schedule Cost

• Construction 5 6 years, and 150 M of total
  cost