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| TUPMA001 | New Connection Cryostat to Insert FP420 Proton Tagging Detector in the LHC Ring | proton, cryogenics, vacuum, controls | 103 | ||
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FP420 is a R&D project to assess the feasibility of installing proton tagging detectors in the region 420m from the interaction points at the LHC. They would function as new sub-detectors at ATLAS/CMS, allowing the measurement of the spatial position and arrival time of outgoing protons emerging almost intact from the collision. Forward proton tagging in this region is expected to open a new programme of electroweak, QCD and BSM physics. At present the 420m region is enclosed in a 'connection cryostat' (maintained at 1.9K) that provides continuity for the LHC beam, cryogenic & vacuum services and electrical power circuits through superconducting bus bars. The requirement of near room temperature operation and critical position control close to the beam pipes has made inserting FP420 detectors in this region a very complex task. The currently favoured design calls for the replacement of the connection cryostats with a new ~12m long assembly that will have all the necessary features of the existing connections cryostat as well as the appropriate environment for the operation of the detectors. This paper mainly describes the cryogenic aspects of the new connection cryostat.
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| TUPMA020 | Beam Based Alignment and COD Correction for the Siam Photon Source | quadrupole, photon, controls, betatron | 130 | ||
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The first systematic Beam based Alignment (BBA) and COD correction attempt for the Siam Photon Source has been performed. Automated measurements were carried out using MATLAB OPC Toolbox, interfacing to the PLCs of the accelerator control system. Calculations of theoretical parameters were performed with Accelerator Toolbox via MATLAB interface. Since the Beam Position Monitors (BPMs) were not properly calibrated prior to installation beam based calibrations were carried out. Preliminary calibration factors for each BPM were obtained by normalizing BPM signals to modeled steering magnet responses. Measurements of offsets between BPM and quadrupole centers were performed by fitting for minima of orbit response to changes of quadrupole strengths. The resulting offsets were superimposed to the BPM readings in the PLC. COD correction was then performed.
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| WEPMA048 | Beam Position Monitor at SCSS Prototype Accelerator | undulator, acceleration, dipole, coupling | 387 | ||
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The SCSS X-ray free electron laser (XFEL) project is in progress at SPring-8. The SCSS prototype accelerator for VUV-FEL has been constructed and is in operation. The required resolution of the beam position is less than 1um for XFEL (10um for VUV-FEL). A cavity RF-BPM (Radio Frequency Beam Position Monitor) was developed for the SCSS accelerator based on the past experiment in which the position resolution of several 10nm was achieved. In the prototype accelerator, the beam-based calibration method of the RF-BPM was established. An experiment to evaluate the position resolution was also performed, and the preliminary result was obtained to be less than 5um. This result is sufficient for VUV-FEL. The RF-BPM made important contributions to the tuning of the prototype accelerator such as beam optics measurements and VUV-FEL amplification. By using RF-BPM data, for example, the envelope of the beam trajectory was visualized and the beam was straightly passed through undulators. As a result, VUV-FEL amplification was observed in the wavelength region of 40-60nm.
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| THPMA081 | Precise Positioning of Magnetic Field Centers of Quadrupole Magnets on the Girder | quadrupole, laser, synchrotron, target | 749 | ||
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Conventional alignment of quadrupole magnet on the girder is mainly based on the measurement of theodolite and fiducial. Most of the measurement errors come from human-eye resolution and fiducial precision. The resultant cumulative error could be in the order of 50~100μm. In this paper, pulsed wire method is proposed to align group of quadrupole magnets concentrically on one girder to precision about 10μm. In order to increase the alignment accuracy, sag problem in tension wire is replaced by a short wire with laser PSD system. Descriptions of the setup and test results are presented.
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| THPMA083 | The Magnet Alignment Method For The J-PARC Main Ring | target, site, quadrupole, sextupole | 752 | ||
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In the J-PARC site, the inflastructure for the whole site measurement is planned for the global alignment of the accelerator components. For the neutrino experiments, the J-PARC main ring must be directed to the SUPER-KAMIOKANDE exactly. The global measurements from the Kamioka site to the J-PARC site is carried out by using GPS system on the gound level. Several measurement holes, in order to tranport the coodinates from the ground level into the accelerator floor level directly, are prepared around the J-PARC accelerator complex. The magnet alignment method for the J-PARC main ring are reported with the present alignment status.
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| THPMA085 | Mechanical Coupling between the LHC Cryogenic Distribution Line and the Short Straight Section housing the Superconducting Quadrupole. Theoretical Analysis and Experimental Validation | vacuum, coupling, collider, hadron | 758 | ||
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The cryogenic module of the Short Straight Section (SSS) of Large Hadron Collider (LHC) is supplied with liquid & gaseous Helium through a jumper connection, which links the valve distribution box of the Cryogenic Distribution Line (QRL) & the SSS. The internal as well as external features of the jumper construction allow for sufficient flexibility to reduce the reaction forces responsible for elastic deformations when the SSS is moved for alignment. The SSS is composed of a cold mass and an external vacuum vessel equipped with fiducials for allowing the precise alignment of the machine when the cryostat is finally closed. A deformation of the structure from reaction forces induced by relative displacements of the SSS and the QRL, if unpredictable, would result in a dangerous misalignment of the quadrupole magnetic axis. A unified FE model, validated by a 40 meter long dedicated test setup at CERN, was generated at RRCAT to study the elastic behaviour of the SSS under the conditions of alignment. Transfer functions linking the action on the SSS external alignment jacks and the position of the cold mass are now available that will be used to properly align the machine in operation.
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| THPMA086 | Precise Survey and Alignment of Synchrotron Radiation Source Indus-2 | controls, survey, dipole, quadrupole | 761 | ||
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The 2.5GeV third generation synchrotron light source Indus-2 at RRCAT, which in advance stage of commissioning, demanded a high precision of survey and alignment of all its components. In particular, we had to control the transverse and azimuthal positions of all quadrupoles and dipoles within a relative accuracy of 0.1 mm and overall circumference within 2.5 mm. This required a tight control over all the sources of errors starting from fiducializations, survey of networks, final alignment and smoothing. We have successfully accomplished this task by adopting the triangulation-trilateration technique of survey and alignment along with indigenously developed software for online survey data collection, least square adjustment of redundant measurements and error analysis. The accuracy of alignment was reflected from the successful circulation and storage of electron beam in the machine with a very small closed orbit distortion. This paper, in brief, presents the methodology adopted for survey and alignment and final accuracies achieved.
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