Philip Burrows

Abstract:

The design luminosity for the future linear colliders is very demanding and challenging. Beam-based feedback systems will be required to achieve the necessary beam-beam stability and steer the two beams into collision. In particular we have studied the luminosity performance improvement by intra-train beam-based feedback systems for position and angle corrections at the interaction point. We have set up a simulation model which introduces different machine imperfections and can be applied to both the International Linear Collider (ILC) and the Compact Linear Collider (CLIC).

Abstract:

Particle physics is on the threshold of major discoveries which will shed light on the origin of mass, dark matter, and possible extra spatial dimensions in nature. Future particle accelerators will recreate matter conditions not seen since the first few billionths of a second after the Big Bang. The engineering challenges are immense. 30km-long straight tunnels must be drilled to house the accelerator, and components must be aligned and stabilised to microns over distances of kilometers. High-power superconducting niobium radio-frequency cavities will drive electron and positron beams to velocities approaching the speed of light. The beams must be made a few nanometers in size, and collided head-on after traversing tens of kilometers. Feedback and control systems must keep the beams in collision on nanosecond timescales. The paper will review these extreme engineering challenges and report on the advanced R&D being done in the UK and elsewhere to get us to our physics goals. © 2008 IOP Publishing Ltd.

Abstract:

Two experimental detectors working in a push-pull mode has been considered for the Interaction Region of the International Linear Collider [1]. The push-pull mode of operation sets specific requirements and challenges for many systems of detector and machine, in particular for the IR magnets, for the cryogenics and alignment system, for beamline shielding, for detector design and overall integration, and so on. These challenges and the identified conceptual solutions discussed in the paper intend to form a draft of the Interface Document which will be developed further in the nearest future. The authors of the present paper include the organizers and conveners of working groups of the workshop on engineering design of interaction region IRENG07 [2], the leaders of the IR Integration within Global Design Effort Beam Delivery System, and the representatives from each detector concept submitting the Letters Of Intent.

Abstract:

We present the design and preliminary results of a prototype beam-based digital feedback system for the Interaction Point of the International Linear Collider. A custom analogue front-end processor, FPGA-based digital signal processing board, and kicker drive amplifier have been designed, built, and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The system was measured to have a latency of approximately 140 ns.

Abstract:

Beam-beam background impacts on the IP BPM are studied for the CLIC machine. The large number of coherent pairs (1.8 × 108 charges per BPM strip per bunch crossing) for the CLIC-G default parameter set, potentially leads to a large secondary emission in the BPM strips. Detailed GuineaPig++ and Geant studies reveal, however, that the coherent pairs travel down the extraction line without significant secondary showering. Geant studies of the CLIC incoherent pairs show a flux of secondary emission two orders of magnitude less than that expected for the ILC 1 TeV high luminosity scheme. Since previous studies showed that FONT IP BPM signal distortion for the ILC was of no concern, then it can also be neglected at CLIC.