A prototype energy spectrometer for the ILC at end station a in SLAC
The main physics program of the International Linear Collider requires a measurement of the beam energy with a relative precision of the order 10-4 or better. A magnetic spectrometer using high resolution beam position monitors (BPMs) has been proposed to achieve this goal. A prototype spectrometer chicane employing four dipole magnets is currently under development at the End Station A in SLAC, intending to demonstrate the required resolution and stability of this method and investigate possible systematic effects and operational issues. This contribution reports on the successful commissioning of the beam position monitor system and the resolution and stability achieved. Also, the initial results from a run with a full spectrometer chicane are presented.
Analysis of an asymmetric resonant cavity as a beam monitor
We analyze the excitation of an arbitrary, externally coupled resonant structure by a charged particle beam, providing a rigorous formulation of the effect of spurious modes and intrinsic mode nonlinearity on inferred beam coordinates. Results are illustrated for a two-cavity system employed for beam-position monitoring with an idealized front-end signal processor.
Proposal to Increase the LEP Energy with Horizontal Orbit Correctors
In an e + e − collider the beam energy depends only on the bending field integral Bd s while the synchrotron radiation power scales with B 2 ds and is sensitive to the details of the field distribution. With fixed RF acceleration voltage it is thus possible to attain higher energies by increasing the effective bending magnet length. We propose to use the horizontal orbit correctors to exploit this effect. To control the orbit perturbations, 79 unconnected correctors in the regular arcs and 14 un-connected correctors in the dispersion suppressors will have to be powered. An energy increase of approximatively 0.18 GeV per beam might be obtained.