The NLC 2001 Beam Delivery Configuration
The IR Systems
Requirements:
The interaction region halls must house the chosen detectors, allow for their assembly and maintenance, and provide a quiet, stable platform so that high luminosity collisions are maintained.
Technical description:
Overall Layout
The Interaction Halls have been sized assuming that one would house the NLC “Large” Detector and that one would house the “Small” Detector. See the table below for the list of driving parameters. An “SLD” detector model, where the barrel is a complete cylinder and where the endcaps are doors that move along the cylinder axis, has been assumed. The hall length (transverse to the beam) is large enough to allow assembly of the detector while a concrete wall shields the interaction point. The wall would also serve as radiation shielding if the detector is not deemed to be “self-shielded.” If the detector were built-in-place, on the beam line, and could be self shielded, the length could be reduced by roughly a factor of three. The hall width (length parallel to the beamline) is set by the constraint that the doors open just enough to allow servicing of the inner detectors.
NLC Small Detector in the Floorplan
NLC Small Detector in the Pit
NLC Large Detector Floorplan
NLC Large Detector in the Pit
Parameter table
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Detector / Pit Parameters |
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Modified 10-20-99 |
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Small Detector |
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Large Detector |
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Detector footprint |
12 X 11.0 |
m |
20 X 20 |
m |
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| Pit Length |
40 |
m |
62 |
m | |||
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Pit Width |
20 |
m |
30 |
m |
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Pit depth below beamline |
5 |
m |
7 |
m |
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Max hook height above apron |
11 |
m |
14 |
m |
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Door Height |
10 |
m |
13 |
m |
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Door width |
10 |
m |
13 |
m |
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Crane overlap of apron |
14 |
m |
14 |
m |
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Welding outlet spacing (on pit walls) |
5 |
m |
5 |
m |
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Barrel weight |
2000 |
MT |
7300 |
MT |
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1 Door weight |
500 |
MT |
1900 |
MT |
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Total Weight |
3100 |
MT |
11100 |
MT |
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Pointers to subsystem docs
http://www-sldnt.slac.stanford.edu/nlc/engineering/Facilities_needs_for_NLC_Beam_Delivery_Rev1-6.doc
Pointers to optics decks
There are no optics decks for this subsystem. See the decks for the final focus and the extraction lines.
Open issues
The baseline design assumes that the two IR halls are physically separated so that activities and mechanical equipment operating in one hall are seismically isolated from the other hall. For example, the LIGO experiment has used 100m as a minimum separation for rotating machinery and sensitive detectors. While the means to actively detect and compensate for culturally induced ground vibration is a key element of the NLC R&D program, passive compliance with vibration criteria is the ideal. In principle each of the IR halls could be designed to accommodate two detectors that share the beamline in a push-pull manner, thus increasing experimental opportunities, or the overall NLC layout could be changed to support one push-pull IR only at a considerable cost savings. In any push-pull scheme, major installation activities might need to be curtailed if they introduced uncompensated vibration of the final magnets producing data for the detector currently on the beam line.
Discussion of configuration choices:
The new configuration is subject to review by the physics community.
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Last modified 01/14/04
Tom Markiewicz