632
K. Hübner et al.
final focus quadrupoles [174] against quenches due to beam losses. Quenches of
those magnets have been seen in the Phase 2 commissioning both for the stored and
injected beams.
10.5 Tevatron—HERA—LHC
Karl-Hubert Mess · Peter Schmüser
10.5.1 Three Steps in the Evolution of Superconducting
Accelerator Magnets
The first particle accelerator approaching the TeV energy range was the protonantiproton collider Tevatron at the Fermi National Accelerator Laboratory. Much
pioneering work was done at Fermilab, and many of the successful design and
construction principles of the Tevatron dipole and quadrupole magnets have been
adopted at the electron-proton collider HERA and the Large Hadron Collider
LHC (CERN). The superconducting coils used in these accelerators show great
similarities. They are wound with high precision from a multistrand cable containing
many thousand fine niobium-titanium filaments in a copper matrix. The coils have
a helium-transparent insulation and are confined by nonmagnetic clamps (often
called collars). The clamps are assembled from precision-stamped stainless-steel
or aluminum-alloy laminations and serve three purposes: they define the exact coil
geometry, they exert a large prestress on the coils to prevent conductor motion
during excitation of the magnet, and they take up the huge magnetic forces at large
fields. Interesting differences, however, have evolved in the layout of the iron yoke.
The Tevatron magnets are “warm-iron” magnets with a yoke at room temperature
while the HERA and LHC magnets feature a “cold-iron” yoke inside the liquid
helium cryostat.
In the beginning of the HERA project two different design lines were followed.
Our group at DESY constructed and built 6 m long prototype dipoles of the “warmiron” type which were basically copies of the Tevatron dipoles. These magnets
were made with tooling suitable for series production and performed very well,
the design field of 5.2 T was exceeded and excellent field quality was achieved. In
parallel, an industrial company (Brown Bovery in Mannheim) designed and built
two “cold-iron” prototype dipoles following a concept developed at Brookhaven
National Laboratory. Here the coil was surrounded with epoxy-fibreglass form
pieces and then directly mounted in an iron yoke which served as the clamping
structure. Also the BBC dipoles showed remarkable performance. They exceeded
the design field by an ample margin, however the field quality became poor for
K. Hübner et al.
final focus quadrupoles [174] against quenches due to beam losses. Quenches of
those magnets have been seen in the Phase 2 commissioning both for the stored and
injected beams.
10.5 Tevatron—HERA—LHC
Karl-Hubert Mess · Peter Schmüser
10.5.1 Three Steps in the Evolution of Superconducting
Accelerator Magnets
The first particle accelerator approaching the TeV energy range was the protonantiproton collider Tevatron at the Fermi National Accelerator Laboratory. Much
pioneering work was done at Fermilab, and many of the successful design and
construction principles of the Tevatron dipole and quadrupole magnets have been
adopted at the electron-proton collider HERA and the Large Hadron Collider
LHC (CERN). The superconducting coils used in these accelerators show great
similarities. They are wound with high precision from a multistrand cable containing
many thousand fine niobium-titanium filaments in a copper matrix. The coils have
a helium-transparent insulation and are confined by nonmagnetic clamps (often
called collars). The clamps are assembled from precision-stamped stainless-steel
or aluminum-alloy laminations and serve three purposes: they define the exact coil
geometry, they exert a large prestress on the coils to prevent conductor motion
during excitation of the magnet, and they take up the huge magnetic forces at large
fields. Interesting differences, however, have evolved in the layout of the iron yoke.
The Tevatron magnets are “warm-iron” magnets with a yoke at room temperature
while the HERA and LHC magnets feature a “cold-iron” yoke inside the liquid
helium cryostat.
In the beginning of the HERA project two different design lines were followed.
Our group at DESY constructed and built 6 m long prototype dipoles of the “warmiron” type which were basically copies of the Tevatron dipoles. These magnets
were made with tooling suitable for series production and performed very well,
the design field of 5.2 T was exceeded and excellent field quality was achieved. In
parallel, an industrial company (Brown Bovery in Mannheim) designed and built
two “cold-iron” prototype dipoles following a concept developed at Brookhaven
National Laboratory. Here the coil was surrounded with epoxy-fibreglass form
pieces and then directly mounted in an iron yoke which served as the clamping
structure. Also the BBC dipoles showed remarkable performance. They exceeded
the design field by an ample margin, however the field quality became poor for