| Paper | Title | Other Keywords | Page | ||
|---|---|---|---|---|---|
| MOPAN076 | Remote Inspection, Measurement and Handling for LHC | controls, radiation, monitoring, alignment | 332 | ||
|
Personnel access to the LHC tunnel will be restricted to varying extents during the life of the machine due to radiation, cryogenic and pressure hazards. The ability to carry out visual inspection, measurement and handling activities remotely during periods when the LHC tunnel is potentially hazardous offers advantages in terms of safety, accelerator down time, and costs. The first applications identified were remote measurement of radiation levels at the start of shut-down, remote geometrical survey measurements in the collimation regions, and remote visual inspection during pressure testing and initial machine cool-down. In addition, for remote handling operations, it will be necessary to be able to transmit several real-time video images from the tunnel to the control room. The paper describes the design, development and use of a remotely controlled vehicle to demonstrate the feasibility of meeting the above requirements in the LHC tunnel. Design choices are explained along with operating experience to-date and future development plans.
|
|
|
||
| MOPAN081 | The LHC Collimator Controls Architecture - Design and Beam Tests | controls, collimation, beam-losses, injection | 344 | ||
|
The LHC collimation system will require simultaneous management by the LHC control system of more than 500 jaw positioning mechanisms in order to ensure the required beam cleaning and machine protection performance in all machine phases, from injection at 450~GeV to collision at 7~TeV. Each jaw position is a critical parameter for the machine safety which could cause a beam dump. In this paper, the architecture of the LHC collimator controls is presented. The basic design to face the accurate and real-time control of the LHC collimators and the interfaces to the other components of LHC Software Application and control infrastructures are described. The full controls architecture has been tested off-line in dedicated test benches, and in the real accelerator environment in the CERN SPS during beam tests with a full scale collimator prototype. The results and the lessons learned are presented.
|
|
|
||
| TUPAN059 | The Precise Survey and the Alignment Results of the J-PARC Linac | linac, alignment, beam-transport, laser | 1520 | ||
|
J-PARC linear accelerator components have been installed and the beam commissioning has been started in Nov. 2006. A total length is more than 400 m including the beam transport line to the 3GeV RCS(Rapid Cycling Synchrotron). Precise alignment of the accelerator components is essential for high quality beam acceleration. After the completion of the linac building, floor elevation was surveyed periodically for more than one year to adjust the beam height from the ion source to the RCS. Before the beam commissioning, a metrological survey has been done. The reference points on the tunnel wall were set up to form a survey network to reduce the survey error less than 1mm in the entire linac. Based on the survey results, the linac components were re-aligned finely to satisfy the requirement. In this paper, the results of the floor elevation and the final alignment are described.
|
|
|
||
| TUPAN060 | The DTL/SDTL Alignment of the J-PARC Linac | alignment, linac, laser, target | 1523 | ||
|
J-PARC linear accelerator components have been installed and the beam commissioning has been started in Nov. 2006. The length of the linear section is about 300 m which consists of the ion source, the radio frequency quadropole linac(RFQ), the drift tube linac(DTL), separated type DTL(SDTL), and the beam transport line. Precise alignment of the accelerator components is essential for high quality beam acceleration. The required alignment error in the J-PARC linac is 0.1mm in transverse direction. In the DTL/SDTL section, the fine alignment was carried out by using an optical alignment telescope along with the cavity installation. The relay targets were placed at short intervals for smooth connection between neighboring components. After the installation, the DTL/SDTL positions were confirmed by measuring the reference base by using a laser tracker. In this paper, the alignment procedure for the DTL/SDTL section and the results by the laser tracker measurements are described.
|
|
|
||
| WEPMS011 | Comparative Surface Studies on Fine-grain and Single Crystal Niobium Using XPS, AES, EBSD and Profilometry | superconductivity, electron, synchrotron-radiation | 2349 | ||
|
Funding: Supported by NSF |
As the surface magnetic field in niobium cavities approaches the theoretical critical field, rf losses begin to grow sensitive to increasingly subtle features of the material and the surface. A striking example is the familiar occurrence of the high-field Q-slope, where rf losses increase exponentially with field above an onset field. A surprising feature of the high-field Q slope is its positive response to mild baking at 120 C. But the Q-slope returns after the first 20 nm of the niobium metal surface is converted to loss-less pentoxide via anodization, a key feature. The latter result suggests that the cause of the fast growing losses resides in the first 20 nm of the rf surface. Although there are several propositions, the exact mechanism for the high-field Q-slope is not yet fully understood and demands further research. We are conducting surface analytic studies with XPS, SIMS, and Auger to shed light on the mechanism of the high-field Q-slope. We are comparing the behavior of fine-grain samples with single crystal samples, BCP treatments with EP treatments and properties before and after 120 C bake. We also study the effect of baking at temperatures up to 400 C. |
|
||
| THPMS056 | Emittance Preservation in the International Linear Collider Ring to Main Linac Transfer Line | emittance, coupling, simulation, betatron | 3118 | ||
|
Funding: Work supported by the US Department of Energy, contract DE-AC02-76SF00515. |
The very small vertical beam emittance in the International Linear Collider (ILC) can be degraded by dispersion, xy coupling, transverse wakefields, and time-varying transverse fields introduced by elements with misalignments, strength errors, xy rotation errors, or yz rotation errors in the Ring to Main Linac (RTML) transfer line. We present a plan for emittance preservation in this beamline which uses local, quasi-local, and global correction schemes. Results of simulations of the emittance preservation algorithm are also presented and discussed. |
|
||
| THPAN070 | Advances in MAD-X using PTC | lattice, controls, linac | 3381 | ||
|
For the last few years the MAD-X program makes use of the Polymorphic Tracking Code (PTC) to perform calculations related to beam dynamics in the nonlinear regime. An important new feature is the extension of the matching module to allow fitting of non-linear parameters to any order. Moreover, calculations can now be performed with parameter dependence defined in the MAD-X input. In addition, the user can access the PTC routines for the placement of a magnet with arbitrary position and orientation. This facilitates the design of non-standard lattices, in particular since a 3D visualization of a lattice is now available. For the LHC studies during commissioning it is of special interest that one has access to within the thick PTC elements which allows e.g. to find PTC Twiss parameters at any point in the ring. Lastly, the beam-beam element has been added to PTC to complete the set of elements available in MAD-X proper.
|
|
|