BDS civil layouts and upgrade path from single IR to two IRs

1
BDS civil layouts and upgrade path from single IR
to two IRs

• Andrei Seryi
• SLAC
• October 19, 2005

2
Two IRs baseline and alternatives

• Baseline has two Beam Delivery Systems, two
  collider halls separated in z by 130m, for two
  independent experiments
• The paradigm of two BDS, two IRs, two collider
  halls and detector is challenged and likely will
  be changed
• The considered alternative is single IR, single
  or two push-pull detectors, at least at the start
  of ILC
• The intermediate crossing angle alternative has a
  lot of advantages to be a candidate for single IR
• Plan of upgrade to two IRs need to be worked out

3
Single IR baseline and upgrade

• Assume baseline is single IR with 14mrad
• Can have single or two push-pull detectors
• Tunnel stubs included which allow upgrade to have
  two detectors in a single IR that can be chosen
  much later
• The 14mrad angle may still be OK for multi-TeV
  (Daniel Schulte)
• Keep same collider hall for upgrades
• building other collider hall not optimal if the
  first collider hall already has two detectors,
  since moving one of them to another independent
  collider hall is difficult
• Upgrades
• A) 14mrad and small angle, min separation between
  detector, no room for shielding
• B) 14mrad and small angle, larger separation
  between detectors, shielding OK, but adds 1km or
  more to the BDS length
• C) 14mrad and 20mrad (or more), gg, large
  separation between detectors

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Single IR with 14mrad
Tunnel stubs for beam dump
Tunnel stubs for future upgrades. At first stage
can be used as alcoves for diagnostics
electronics, lasers for laser wires, etc.
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Upgrade to two detectors, Version A

• 14mrad and 0-2mrad
• Min separation (1m) between detector (assume
  their Ø15m), no room for shielding
• Detector cannot be serviced independently
• For disassembly, detectors first need to be moved
  out
• But this version saves 1-2km of the BDS length
  (30-60GeV CM higher energy reach)

6
Upgrade A 14mrad small xing
Detectors are placed with min separation, no
shielding in between
The middle tunnel stub was used to continue
tunnel to 2nd IR
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Upgrade to two detectors, Version B

• 14mrad and 0-2mrad
• Large separation between detector, sufficient
  room for shielding
• Detector can be serviced independently
• For disassembly, detectors may stay on place
• But this version adds 1-2km to the BDS length
  (30-60GeV CM lower energy reach)

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Upgrade B 14mrad small xing
Detectors are placed with larger separation,
sufficient to have shielding in between
The first tunnel stub was used to continue tunnel
to 2nd IR
BDS is lengthened by 1-2 km
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Upgrade to two detectors, Version C

• 14mrad and 20mrad (or more)
• Large separation between detector, sufficient
  room for shielding
• Detector can be serviced, constructed, assembled
  independently, on place
• Gamma-gamma compatible

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Upgrade C 14mrad and larger xing
The middle tunnel stub was used to continue
tunnel to 2nd IR
Detectors have large separation, sufficient for
shielding and to construct the gg detector on
place
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CF models

• CF groups are developing 3D models which will
  help to understand construction plan and issues
  and also estimate the cost
• Example on the right isfor baseline with 20
  and2mrad IRs
• Started to create similar models for the single
  IRand its upgrades (next slides)

Fred Asiri et al.
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CF models
Fred Asiri et al.

• Upgrade version A with two detectors close
  together
• Assumed small (SiD) and large detector (LDC or
  GLD)

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CF models
Fred Asiri et al.

• Upgrade version B with two detectors separated by
  5m
• Assumed small (SiD) and large detector (LDC or
  GLD)
• the needed increase of BDS length is less than
  for two 15m detectors

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Conclusion

• The assumed single IR baseline with 14mrad can be
  upgraded to
• A) 14mrad and small angle, min separation between
  detector
• B) 14mrad and small angle, larger separation
  between detectors
• C) 14mrad and 20mrad (or more) large separation
  between detectors, OK for gg
• Other upgrade scenarios may be possible
• Started to discuss possible civil construction
  issues and build models for construction and cost
  estimations