Accelerator Technologies Laboratory
2013-04-22 10:04 UTC |
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The Accelerator Technologies Laboratory is unusual among CERN
facilities in that it is open to the general public. You don't
need to arrange a tour—just show up during business hours,
walk in, and stay out of areas marked forbidden to visitors. This
is where the heavy metal of the LHC was developed and tested,
and continues to qualify components and develop upgrades. If
you don't have a knowledgeable guide or haven't read up in advance
on the components of the LHC, many of these amazing machines may
be a mystery to you, but even so it's inspiring to know that
humans have invented and built them in the quest to understand
nature at its most fundamental level.
This is a big facility; note the bicycles for getting around.
I believe this is a segment of
Linac4,
being developed to replace the current
Linac 2,
which performs the initial acceleration of protons bound for the LHC.
When it goes into service, it will allow increasing the luminosity
(collision rate) of the LHC.
This also appears be a component of Linac4.
Just sayin'.
A section of the LHC tube reveals its inner structure. Note
how the magnet encloses the two beam pipes at the centre,
assuring that protons travelling in opposite directions
are uniformly deflected.
A face-on view of the tube shows the symmetrical magnet structure
enclosing the beam pipes.
In addition to the main magnets, which steer the beam around the LHC ring,
a variety of magnets, shown here, form the beams so they arrive precisely
at the interaction points with maximum density.
High-temperature superconductor current feeds, chilled with liquid
nitrogen, supply current to the ring. This is a cross-section of
a 13,000 ampere feed. Are superconductors cool, or what?
This is an end view of an LHC ring segment. This is a fully functional
spare which could be installed should a segment fail. In the centre
are the two beam tubes. Cooling and electrical feeds occupy the
periphery.
An oblique view shows the scale of this tube. There are a total of
1232 of these 15 metre dipole magnets in the LHC ring. along with
392 5–7 metre long quadrupole magnets which focus the
beam.
This cut-away view shows the junction between two sections of
LHC tube. These connections must accommodate the transition between
room temperature and the 1.9°K operating temperature of the
accelerator, and hence incorporate intricate expansion joints.
This model illustrates one of the notorious splices which
led to the September 19th, 2008
quench
incident, which vented six tonnes of liquid helium into the tunnel
and damaged over 50 superconducting magnets. It was more than a year
before the LHC was repaired and could resume operations. In engineering
on this scale, and at such extremes of energy and temperature, attention
to even the most mundane of details is essential.
The eight sectors of the LHC are separated by isolation valves like this
one. They allow taking a sector offline, storing its liquid helium
coolant in
dewars outside
the accelerator, and bringing the beam tube up
to ambient temperature and atmospheric pressure for maintenance while
maintaining the vacuum and cryogenic temperature of adjacent sectors.
This valve is a wonder to watch operate—words fail to describe it.
These bays allow component testing of sections of the beam pipe and
magnets. Each section in the accelerator was tested here before
being installed in the tunnel.
This document is in the public domain.