Abstracts Brochure - CERN

MOPLS004
MOPLS005
MOPLS006
MOPLS007
26-Jun-06 16:00 - 18:00 MOPLS — Poster Session
Estimation and Analysis of the Machine-induced Background at the TOTEM Roman Pot
Detectors in the IR5 of the LHC
V. Talanov (IHEP Protvino) V. Avati (Helsinki University, Department
of Physics) M. Deile, D. Macina (CERN)
108
The problem of background generation in
the experimental insertion IR5 of the LHC
during machine operation in the dedicated
TOTEM mode with low intensity beams and
the specially designed beta* = 1540 m optics is discussed. The sources of the machine-induced background in the
IR5 forward physics areas are identified and their relative importance is evaluated. The results of the background
simulation in the IR5 are presented, based on the most recent estimates of the residual gas density for TOTEM beam
conditions. The methods for background analysis and rejection are explained.
A Staged Approach to LHC Commissioning
R. Bailey, O.S. Brüning, P. Collier, M. Lamont, R.J. Lauckner, R.
Schmidt (CERN)
After a brief reminder of the performance
goals of the LHC, the overall strategy proposed
for commissioning the machine with
protons is presented. A thorough commis-
sioning of the LHC hardware systems, presently ongoing, will lead into a staged approach for the first two years of
operation with the beam, allowing both the complexity of the machine operation and the destructive power of the
high intensity beams to be introduced in a controlled, incremental manner. The demands on the annual machine
schedule are discussed, including the need to incorporate dedicated running for ions and proton-proton total cross
section measurements. An important pre-commissioning milestone is the injection of the beam into a sector of the
partially completed LHC; the motivation and tests planned are briefly summarised.
Adaptive RF Transient Reduction for High Intensity Beams with Gaps
When a high-intensity beam with bunch-
J. Tuckmantel, P. Baudrenghien (CERN)
trains and gaps passes a cavity with a highgain
vector feedback enforcing a constant
voltage, large transients appear, stressing the RF high power hardware and increasing the trip rate. By modulating
the cavity voltage with a varying periodic waveform (set-function), the RF power can be made constant while
still preserving the high feedback gain. The average cavity voltage is conserved but bunches have to settle at slightly
shifted positions. A method is derived to obtain this set-function in practice while making no assumptions or measurements
of the beam or RF parameters. Adiabatic iterations are made, including the whole machine as an analog
computing device, using all parameters as they are. A computer simulation shows the success of the method.
Monitoring Heavy-ion Beam Losses in the LHC
The LHC beam loss monitor (BLM) system,
R. Bruce, G. Bellodi, H.-H. Braun, S.S. Gilardoni, J.M. Jowett (CERN) primarily designed for proton operation, will
survey particle losses and dump the beam if
the loss rate exceeds a threshold expected to induce magnet quenches. Simulations of beam losses in the full magnet
geometry allow us to compare the response of the BLMs to ion and proton losses and establish preliminary loss