International Linear Collider (ILC) is an electron-positron collider with an initial collision energy of 500 GeV, upgradable to 1 TeV. It will explore the TeV energy scale, shedding light on the physics that lies there. It will complement, and build upon, the discoveries of the LHC. Cornell is developing Time Projection Chamber (TPC) technology for the ILC. We have built a prototype equipped to compare the performance of GEM, MicroMegas and traditional pad readout. Cornell is also involved in planning for a large-scale international prototype. We are also developing TPC reconstruction software. Researcher: Dan Peterson Julia Thom-Levy x-ray beam size monitor as part of the CesrTA project, with the ultimate goal of deploying such a device at the International Linear Collider.
The X-ray beam size monitor, (xBSM) is an instrument for measuring the sizes of the electron and positron beams using synchrotron radiation. The device can measure vertical beam sizes of 10–100 μm on a turn-by-turn, bunch-by-bunch basis at beam energies of ~2GeV. The xBSM images X-rays that emerge from a hard-bend magnet through a single- or multiple-slit (coded aperture) optical element onto an array of 32 InGaAs photodiodes. Beamlines and detectors are entirely in-vacuum, enabling single-shot beam size measurement down to below 0.1 mA (2.5 billion particles) per bunch and inter-bunch spacing of as little as 4 ns. A systematic precision of ~1 micron is achieved for a beam size of ~12 microns. Achieving this precision requires comprehensive alignment and calibration of the detector, optical elements, and X-ray beam. Data from the xBSM have been used to extract characteristics of beam oscillations on long and short timescales, and to make detailed studies of low-emittance tuning, intra-beam scattering, electron cloud effects, and multi-bunch instabilities. Researchers: James Alexander, Dan Peterson, Brian Heltsley
X-ray beam size monitor optics (left) and photo-diode pixel detector (right). Source to optics L~4m. Optics to detector L'~10m.