Status of the LEP Spectrometer Project

by John Matheson (CERN)

Tuesday 30 Nov 1999, 16:00 → 16:15 Europe/Zurich

SL Auditorium (CERN)

At LEP I, measurement of the beam energy was performed with high accuracy by resonant depolarisation. At physics energies for LEP II, polarisation of the beams is not achievable and measurements of the total bending field are used, calibrated against resonant depolarisation over the range 41-60 GeV/beam. Uncertainties arise from regions of the field which are not sampled adequately. The LEP Spectrometer was proposed to give a determination of beam energy for LEP II. The instrument consists of a steel dipole flanked by beam position monitors (BPMs) which allow measurement of changes in the bend angle. The aim is to achieve a relative precision of 1E-4 on the energy, which requires knowledge of the integral magnetic field to 3E-5 and 1 micron resolution from the BPMs. The commissioning of the Spectrometer has been ongoing through 1999. The talk will outline energy measurement at LEP, the Spectrometer hardware and the characterisation of the individual subsystems. The current status of the data analysis from the 1999 running will be reviewed.

Organiser(s): Werner Herr, SL Division * PLEASE NOTE UNUSUAL DAY ! **Tea and coffee will be served at 15:30 in front of the Auditorium.

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