Manchester Christmas meeting 2006: The ILC interaction region and beyond

1
Manchester Christmas meeting 2006The ILC
interaction region and beyond

• Rob Appleby

Happy New Year everyone!
2
This is my first Christmas meeting

• I spend a large fraction of my time working on
  the International Linear Collider (ILC) What
  else? Theoretical beam dynamics, LHC
• The UK is heavily involved in the beam delivery
  system, which starts from the end of the linac
  and finishes at the dumps
• A lot of work has been done on the layout of the
  beam interaction regions (IRs), where the two
  beams collide

3
ILC baseline layout
e-
e

• Baseline (supported by the GDE)
• two BDSs, 20/2mrad, 2 detectors, 2 longitudinally
  separated IR halls

4
The baseline design of the IRs

• The baseline design consists of two independent
  interaction regions, with two independent
  detectors
• BUT, there is considerable pressure to reduce
  this to a single IR layout
• Hence, the baseline specifies two alternatives
• two BDSs, 20/2mrad, 2 detectors in a single IR
  hall _at_ z0
• Single IR/BDS, collider hall long enough for two
  push-pull detectors
• The next couple of slides take a closer look at
  the IRs and extraction lines of the two baseline
  crossing angles

5
Design features of 20mrad extraction line
Key design feature Incoming and outgoing beams do
not see the same magnets
6
2mrad Extraction Line
SC QD (r ? 35mm) 215 T/m
warm QF (r 10mm) 150 T/m
9m
2 mrad
l3.51m
6-7 mrad
? optical transfer
Key design feature Incoming and outgoing beams
share the same magnets. This is a direct
consequence of the small crossing angle
to beam diagnostics
7

• SC super septum quadrupole and Panofsky septum
  quadrupole designs under study for the first
  extraction magnets where horizontal separation is
  limited.

Super Septum Quadrupole B. Parker
Warm Panofsky Quadrupole C. Spencer
8
What else could we do?

• The choice of 2mrad and 20mrad has emerged from a
  long (and ongoing) debate
• Other alternatives are
• Colliding the beams head-on (tried for the TESLA
  projectvery hard but not dead yet!)
• Pushing the 20mrad down, but still having
  separate magnetsgives you 14mrad (this is under
  study and favoured by our US colleagues)
• 7mrad, 25mrad.all have some advantages
• Finally, if we drop to 1 IRwhat do we choose?

9
Once the beam has been extracted, the show is not
quite over1!
1 This is not generally appreciated, even among
accelerator physicists!
10
How do you dump a 20MW particle beam?
A water dump was used at the SLC. It was rated to
2MW but only ever used to 800kW. This jump to
20MW is considerable
11
(No Transcript)
12
Summary

• The ILC IR baseline has taken a long time to
  reach the current point, and there is a long way
  to go.
• Currently the configuration is 2mrad and 20mrad,
  but the number of IRs and the choice of crossing
  angle may chance, and is a very contentious point
• Finally, we also need to worry about dumping the
  charged particle beam the UK is now taking a
  strong lead in this aspect of the ILC