International Linear Collider (Accelerator Physics)
Illustration of ILC main linac tunnel (courtesy KEK).
There is broad international agreement that the next major project for accelerator-based high energy physics should be a TeV-scale electron-positron linear collider. This project, dubbed the International Linear Collider
, is proposed for construction and operation in the next decade.
At Cornell, the accelerator and HEP groups intend to play major
roles in the design, construction, and operation of the International
Linear Collider. The specific areas where Cornell's expertise has
already played and will continue to play a major role in the linear
collider are damping rings, tracking simulation, RF cavities,
detectors, and accelerator operation.
Damping Ring Studies
CESR-c superferric wiggler design (left) and installed in cryostat (right).
CESR is currently the only wiggler-dominated storage ring in the
world, and operates at energies very close to those of LC damping
rings (a few GeV). Those facts put Cornell in a unique position to
perform experimental studies of the dynamics expected in LC damping
rings. Some projects include
- dynamic aperture studies
- superferric wiggler design optimization
- simulating space charge forces
- CESR Test Accelerator
Low-Emittance Transport Tracking Simulations
Schematic of the entire ILC machine.
Working with Cornell HEP faculty, the group aims to simulate the
tracking of the beam through the entire ILC lattice from the electron
source to the interaction point, including the damping rings, bunch
compressors, main linac, and beam delivery system. These simulations
will study low emittance preservation and beam alignment techniques
under various real-world machine configurations, including: stray
fields, Earth's magnetic field, beam jitter, and static and dynamic
Development of a Helical Undulator for the ILC Positron Source
Undulator cold mass for ILC polarized-positron source.
The polarized-positron source for the ILC includes the undulator, photon
target, collection optics and collimation system. Present work at LEPP
is concentrated on developing an undulator which satisfies the requirements of
the Baseline Configuration Design (BCD)
with the far-term goal of a fully-designed undulator-based positron source.
The goal of our current proposal is to design and manufacture a fully
operational 0.3m long cold mass. All parameters (other than the shorter
length), such as 10 and 12 mm period, 8 mm aperture, and magnetic field values
will be identical to the full version of the undulator. This device will be
tested in liquid helium, and fields will be measured and compared with
This device will be ready for further implementation in 4 m long module,
which we also propose to design. (The BCD suggests that a ~100 m long undulator
will be built in 4 m long sections.)
RF Cavity Technology
In order to reduce the number of rf cavities (and the overall
length of the accelerator) while maintaining the design collision
energy, each cavity must provide a proportionally larger accelerating
gradient. The SRF group is designing new cavity shapes which lower the surface
magnetic field and raise the maximum theoretical accelerating field.
Such cavities have been constructed and have achieved record-setting
accelerating gradients and Q values.