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collider

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IT05 Results with LHC Beam Instrumentation Prototypes instrumentation, diagnostics, LHC, storage-ring 21
 
  • C. Fischer
    CERN, Geneva, Switzerland
  The beam instrumentation foreseen to provide the necessary diagnostics in the transfer lines and in the main rings of the LHC was conceived in the past years. The requirements expected from the different systems are now being closely analyzed and specified. In a few cases, tests of prototypes have already been performed, profiting from the facilities offered by existing machines. The beam position measurement system had to be tackled first, as the pick-ups had to be integrated into the cryogenic part of the machine. Over the last two years other topics started to be experimentally investigated in order to define the best way to meet the requirements for the LHC era. Amongst these different studies are luminosity monitoring devices, various instruments for the measurement of the transverse beam distributions, the use of head-tail sampling to measure the beam chromaticity and quadrupole gradient modulation to derive the local amplitude of the lattice function. The paper discusses the results of these tests.  
 
IT11 Possible Spin-Offs from LHC Physics Experiments for Beam Instrumentation instrumentation, diagnostics, storage-ring, LHC 51
 
  • R. Jones
    CERN, Geneva, Switzerland
  This paper aims to introduce some of the new technology and materials used in the construction of the LHC physics experiments into the domain of the beam instrumentalist. The development of radiation hard fibre-optic technology, for example, can equally well be applied to beam instrumentation systems for the direct transmission of analogue or digital signals from high to low radiation environments. Many electronics techniques such as a system developed for the fast integration of photomultiplier signals could also prove very useful in the construction of new beam diagnostic instruments for bunch-to-bunch measurements. Other topics covered will include a fast beam synchronous timing system based on laser technology and a look at pixel detectors as a possible replacement for CCD cameras in imaging applications.  
 
CT11 New Development of a Radiation-Hard Polycrystalline CDTE Detector for LHC Luminosity Monitoring instrumentation, diagnostics, storage-ring, LHC, luminosity 94
 
  • E. Rossa, H. Schmickler
    CERN, Geneva, Switzerland
  • A. Brambilla, L. Verger, F. Mongellaz
    LETI, Grenoble, France
  Detectors presently considered for monitoring and control of the LHC luminosity will sample the hadronic/electromagnetic showers produced by neutrons and photons in copper absorbers designed to protect the superconducting magnets from quenching. At this location the detectors will have to withstand extreme radiation levels and their long term operation will have to be assured without requiring human intervention. For this application we have successfully tested thick poly-crystalline-CdTe detectors. The paper summarizes the results obtained on rise-times, sensitivity and resistance to neutron irradiation up to a dose of 1015/cm2.  
 
PM14 LHC Beam Loss Monitors instrumentation, diagnostics, beam-losses, LHC, simulation 198
 
  • A.A. Garcia, B. Dehning, G. Ferioli, E. Gschwendtner
    CERN, Geneva, Switzerland
  At the Large Hadron Collider (LHC) a beam loss system will be installed for a continuous surveillance of particle losses. These beam particles deposit their energy in the super-conducting coils leading to temperature increase, possible magnet quenches and damages. Detailed simulations have shown that a set of six detectors outside the cryostats of the quadrupole magnets in the regular arc cells are needed to completely diagnose the expected beam losses and hence protect the magnets. To characterize the quench levels different loss rates are identified. In order to cover all possible quench scenarios the dynamic range of the beam loss monitors has to be matched to the simulated loss rates. For that purpose different detector systems (PIN-diodes and ionization chambers) are compared.  
 
PM17 First Beam Tests for the Prototype LHC Orbit and Trajectory System in the CERN-SPS instrumentation, diagnostics, pick-up, closed-orbit, LHC, controls 207
 
  • D. Cocq, L. Jensen, R. Jones, J.J. Savioz
    CERN, Geneva, Switzerland
  • D. Bishop, B. Roberts, G. Waters
    TRIUMF, Vancouver, Canada
  The first beam tests for the prototype LHC orbit and trajectory system were performed during the year 2000 in the CERN-SPS. The system is composed of a wide-band time normaliser, which converts the analogue pick-up signals into a 10 bit position at 40MHz, and a digital acquisition board, which is used to process and store the relevant data. This paper describes the hardware involved and presents the results of the first tests with beam.  
 
PM19 The Dynamic Tracking Acquisition System for DAΦNE e+/e--Collider instrumentation, diagnostics, pick-up, closed-orbit, controls, DAPHNE 213
 
  • A. Drago, A. Stella, M. Serio
    INFN-LNF, Laboratori Nazionali di Frascati, Frascati, Italy
  The goal of this paper is to describe the dynamic tracking acquisition system implemented for the DAΦNE e+/e--collider at LNF/INFN. We have been using the system since last year and it has been possible to collect useful information to tune-up the machine. A four-button BPM is used to obtain the sum and difference signals in both the transverse planes. The signals are acquired and recorded by a LeCroy LC574A oscilloscope with the capability to sample the input waveforms using a beam synchronous external clock generated by the DaFne Timing System. The start of acquisition is synchronised to a horizontal kick given by an injection kicker. After capturing up to 5000 consecutive turns, data are sent through a GPIB interface to a PC, for processing, presentation and storage. A calibration routine permits to convert voltage data to millimeters values. The acquisition and control program first shows the decay time in number of turns. Then it draws a trajectory in the phase space (position and speed) in both the transverse planes. To do this the software builds a data vector relative to a second "virtual" monitor advanced by 90 degrees. This is done by two alternative ways: applying the Hilbert transform or using the transport matrix method. Examples of data acquired during the collider tune-up are shown.