Title :
Wire scanners at LEP
Author :
Bouchet, B. ; Bovet, C. ; Burns, A. ; Camas, J. ; Ferioli, G. ; Fischer, C. ; Jung, R. ; King, Q. ; Kissler, K.H. ; Koopman, J. ; Mann, J. ; Michel, H. ; Schmidt, R. ; Vos, L.
Author_Institution :
CERN, Geneva, Switzerland
Abstract :
Two sets of wire scanners, each for measuring the horizontal and vertical profile, are installed in LEP in a straight section where the dispersion in both planes is zero. The authors present the design and discuss some limitations of the instrument. A carbon fiber with a diameter of 36 mu m moves through the beam with a speed of about 0.5 m/s. The bremsstrahlung photons generated by the passage of the wire through the beam are detected in scintillators located 80-m downstream. During the first months of LEP operation, the fibers were destroyed occasionally. The various causes, tests and remedies are discussed. At injection energy a significant blowup of the beam results from the wire scan and has to be taken into account for the estimation of the genuine emittance. A model of this blowup is proposed, where the effect is renormalized on the actual measured data. This provides an effective data treatment to obtain the unperturbed beam size.<>
Keywords :
electron accelerators; particle beam diagnostics; storage rings; synchrotrons; LEP; beam monitoring; bremsstrahlung photons; emittance; particle beam diagnostics; scintillators; wire scanners; Carbon dioxide; Dispersion; Magnets; Optical feedback; Particle beams; Photomultipliers; Position measurement; Pulse measurements; Synchrotron radiation; Wire;
Conference_Titel :
Particle Accelerator Conference, 1991. Accelerator Science and Technology., Conference Record of the 1991 IEEE
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-7803-0135-8
DOI :
10.1109/PAC.1991.164575
