70 research outputs found
Handling 1 MW losses with the LHC collimation system
The LHC superconducting magnets in the dispersion suppressor of IR7 are the most exposed to beam losses leaking
from the betatron collimation system and represent the main
limitation for the halo cleaning. In 2013, quench tests were
performed at 4 TeV to improve the quench limit estimates,
which determine the maximum allowed beam loss rate for
a given collimation cleaning. The main goal of the collimation quench test was to try to quench the magnets by increasing losses at the collimators. Losses of up to 1 MW over a
few seconds were generated by blowing up the beam, achieving total losses of about 5.8 MJ. These controlled losses exceeded by a factor 2 the collimation design value, and the
magnets did not quench.peer-reviewe
Quench tests at the Large Hadron Collider with collimation losses at 3.5 Z TeV
The Large Hadron Collider (LHC) has been operating
since 2010 at 3.5 TeV and 4.0 TeV without experiencing
quenches induced by losses from circulating beams. This
situation might change at 7 TeV where the quench margins in the super-conducting magnets are reduced. The
critical locations are the dispersion suppressors (DSs) at either side of the cleaning and experimental insertions, where
dispersive losses are maximum. It is therefore crucial to
understand the quench limits with beam loss distributions
alike those occurring in standard operation. In order to address this aspect, quench tests were performed by inducing
large beam losses on the primary collimators of the betatron
cleaning insertion, for proton and lead ion beams of 3.5 Z
TeV, to probe the quench limits of the DS magnets. Losses
up to 500 kW were achieved without quenches. The measurement technique and the results obtained are presented,
with observations of heat loads in the cryogenics system.peer-reviewe
Collimation for the LHC high intensity beams
The unprecedented design intensities of the LHC require several important advances in beam collimation. With its more than 100 collimators, acting on various planes and beams, the LHC collimation system is the biggest and most performing such system ever designed and constructed. The solution for LHC collimation is explained, the technical components are introduced and the initial performance is presented. Residual beam leakage from the system is analysed. Measurements and simulations are presented which show that collimation efficiencies of better than 99.97 % have been measured with the 3.5 TeV proton beams of the LHC, in excellent agreement with expectations.peer-reviewe
Measuring Coalescence Radii And Flow Using Identified Protons And Deuterons From Na44
4.44> \Deltap, is \Sigma20% of the nominal momentum setting. Tracks through the spectrometer are reconstructed with 3 wire chambers with pad and strip cathode readout (oe Ăź 200ÂŻm) and 3 hodoscopes with an average time of flight resolution of 100 ps. Two threshold Cherenkov counters are used to veto electrons and pions. This analysis compares deuterons from the 8 GeV/c momentum setting to protons from the 4 GeV/c setting at the same velocity. The rapidity range of the data is 1:9 y 2:3. The centrality trigger selects 8.7, 10.7 and 27% of the events with the highest multiplicity for S+S, S+Pb and Pb+Pb collisions, respectively. No further selection on higher centrality was performed. The beam was provided by the CERN SPS accelerator at an energy of 200 A GeV for the sulphur and 158 A GeV for the lead beam. The contamination of
Beam Diagnostic Challenges for High Energy Hadron Colliders
Two high energy hadron colliders are currently in the operational phase of their life-cycle, RHIC and LHC. A major upgrade of the LHC, HL-LHC, planned for 2023 aims at accumulating ten times the design integrated luminosity by 2035. Still further in the future, studies of SppC and FCC are investigating machines with a center-of-mass energy of up to 100 TeV and up to 100 km circumference. The existing machines pose considerable diagnostic challenges, which will become even more critical with any increase in size and energy. Cryogenic environments lead to additional difficulties for diagnostics and further limit the applicability of intercepting devices, making non-invasive profile and halo measurements essential. The sheer size of these colliders requires the use of radiation tolerant read-out electronics in the tunnel and low noise, low loss signal transmission. It also implies a very large number of beam position and loss monitors, all of which have to be highly reliable. To fully understand the machine and tackle beam instabilities bunch-by-bunch measurements become increasingly important for all diagnostic systems. This contribution discusses current developments in the field
Beam Loss Monitoring for Demanding Environments
Beam loss monitoring (BLM) is a key protection system for machines using beams with damage potential and is an essential beam diagnostic tool for any machine. All BLM systems are based on the observation of secondary particle showers originating from escaping beam particles. With ever higher beam energies and intensities, the loss of even a tiny fraction of the beam can lead to damage or, in the case of superconducting machines, quenches. Losses also lead to material ageing and activation and should therefore be well controlled and reduced to a minimum. The ideal BLM system would have full machine coverage and the capability to accurately quantify the number of lost beam particles from the measured secondary shower. Position and time resolution, dynamic range, noise levels and radiation hardness all have to be considered, while at the same time optimising the system for reliability, availability and maintainability. This contribution will focus on design choices for BLM systems operating in demanding environments, with a special emphasis on measuring particle losses in the presence of synchrotron radiation and other background sources
Figure of merit for muon cooling—an algorithm for particle counting in coupled phase planes
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