The Mission:

1
The Mission In order to produce luminosities
appropriate for Run II levels, a better
understanding of the Tevatrons orbit would be
required. To do that, it was necessary to create
a network of survey control points and measure
the positions of all components of the Tevatron.
A 3D Cartesian system, with a precision of lt
2.5-mm (one sigma) across the ring, was
specified. With measured positions of all
components in this system, a precise definition
of the machine is possible. This effort is known
as TeVnet.
The Approach Using techniques similar to those
used in the alignment of the Main Injector,
establish a network of survey points in the
tunnel and on the surface, prepare a pre-analysis
of survey observations to achieve the objectives,
perform the necessary measurements during the
Fall shutdown, and perform a least-squares
adjustment of the data.

• Equipment/Task List
• Two LaserTrackers
• Seven GPS receivers
• Gyro-azimuth theodolite
• Geodimeter Autolock robotic total station
• Digital levels
• Mekometer laser EDM
• Nadir telescopes
• Create observation points in vent shafts
• Install 12 observing towers
• Install a network of 35 DRM
• Tie in principal monuments of Main Injector,
  P-bar, and NuMI
• Tie network to NGS-HARN
• Perform network adjustment
• Determine magnet positions

• Network elements
• 482 LaserTracker stations
• 69658 LaserTracker observations
• 25498 LaserTracker chords
• 612 GPS baselines
• 141 Mekometer distances
• 24 Gyro azimuths
• 82 Autolock angles
• 14 vertical drops
• 893 Tunnel elev. differences
• 86 Surface elev. difference
• 1824 network control points
• 7 months of planning
• 200 field crew man-weeks
• 6 loaner personnel
• 3 contract personnel
• 14 staff-months of analysis

• Glossary
• DRM Deep Rod Monument lengths of aluminum
  rod, driven into the ground to refusal, approx.
  10-15 meters
• NGS-HARN National Geodetic Survey HARN High
  Accuracy Reference Network, in global coordinate
  reference frame
• LaserTracker an instrument using a laser
  interferometer, together with horizontal and
  vertical angle encoders
• GPS Global Positioning System, used in
  differential mode
• Murphy Line a system of brass plugs in the
  tunnel, established in the early 1980s, which
  represent a set of tangent offset lines wrt. the
  quad in each cell of the Main Ring. The
  relationship between any two Murphy lines was
  only loosely known prior to the TeVnet survey.
• Sight-riser A vertical penetration from the
  surface to the tunnel thereby allowing the
  transfer of control to the tunnel.

TeVnet Surveying the Big Machine Fermilab
Alignment Metrology Group
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