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A Design Library of Magnet Support - a Proposal -

Description: Although the ideal and universal support system has not been invented yet, there are many implementations which fulfill most of alignment's requirements. However, inventing a new support system seems to represent the last design challenge, why would we otherwise witness so many new attempts. Already Plato reminded his scholars that one should learn from the past. Unfortunately, learning from previous designs and implementations doesn't seem to carry much attraction. Or it is that we, the customers, are not doing our job by letting the design engineer know what we would like to see done, what we think works, and what is already there. This contribution is an initiative to create a reference for support systems which exist in our laboratories and we know do work. Such an undertaking will require everybody's active support and feedback. I already have to thank my peers at many laboratories who helped me put together this first draft. Only if a more or less complete library of existing designs can be compiled with easy access to drawings can we then hope that the support system design competition looses its challenge. As alignment tolerances get ever tighter, the interplay of alignment with mechanical engineering becomes ever more important. In fact, accelerator alignment has advanced so far that mechanical uncertainties now exceed observational uncertainties. Of the mechanical issues bearing upon alignment, one of the most crucial is the magnet supports; these must provide both stability and a fineness of motion substantially exceeding the final alignment tolerances. Magnet supports are the interface that allows mechanical mounting of components and their subsequent alignment to a nominal position in three-dimensional space. Supports thus provide two functions: that of a spacer to bring the component close to its ideal position, and that of a fine motion system to enable the surveyor ...
Date: August 16, 2005
Creator: Ruland, Robert E.
Partner: UNT Libraries Government Documents Department

The Chesapeake Laser Tracker in Industrial Metrology

Description: In the summer of 1992, the survey and alignment team at the Stanford Linear Accelerator Center acquired a CMS3000 laser tracker manufactured by Chesapeake Laser Systems in Lanham, Maryland. This paper gives a description of the principles of operation and calibration of the tracker. Several applications are explained and the results shared.
Date: August 16, 2005
Creator: Ruland, Robert E.
Partner: UNT Libraries Government Documents Department

Laser Tracker Calibration - Testing the Angle Measurement System -

Description: Physics experiments at the SLAC National Accelerator Laboratory (SLAC) usually require high accuracy positioning, e. g. 100 {micro}m over a distance of 150 m or 25 {micro}m in a 10 x 10 x 3 meter volume. Laser tracker measurement systems have become one of the most important tools for achieving these accuracies when mapping components. The accuracy of these measurements is related to the manufacturing tolerances of various individual components, the resolutions of measurement systems, the overall precision of the assembly, and how well imperfections can be modeled. As with theodolites and total stations, one can remove the effects of most assembly and calibration errors by measuring targets in both direct and reverse positions and computing the mean to obtain the result. However, this approach does not compensate for errors originating from the encoder system. In order to improve and gain a better understanding of laser tracker angle measurement tolerances we extended our laboratory's capabilities with the addition of a horizontal angle calibration test stand. This setup is based on the use of a high precision rotary table providing an angular accuracy of better than 0.2 arcsec. Presently, our setup permits only tests of the horizontal angle measurement system. A test stand for vertical angle calibration is under construction. Distance measurements (LECOCQ & FUSS, 2000) are compared to an interferometer bench for distances of up to 32 m. Together both tests provide a better understanding of the instrument and how it should be operated. The observations also provide a reasonable estimate of covariance information of the measurements according to their actual performance for network adjustments.
Date: December 5, 2008
Creator: Gassner, Georg & Ruland, Robert
Partner: UNT Libraries Government Documents Department

Alignment of the VISA Undulator

Description: The Visible-Infrared SASE Amplifier (VISA) undulator consists of four 99cm long segments. Each undulator segment is set up on a pulsed-wire bench, to characterize the magnetic properties and to locate the magnetic axis of the FODO array. Subsequently, the location of the magnetic axis, as defined by the wire, is referenced to tooling balls on each magnet segment by means of a straightness interferometer. After installation in the vacuum chamber, the four magnet segments are aligned with respect to themselves and globally to the beam line reference laser. A specially designed alignment fixture is used to mount one straightness interferometer each in the horizontal and vertical plane of the beam. The goal of these procedures is to keep the combined rms trajectory error, due to magnetic and alignment errors, to 50{micro}m.
Date: April 15, 1999
Creator: Ruland, Robert
Partner: UNT Libraries Government Documents Department

- GEONET - A Realization of an Automated Data Flow for Data Collecting, Processing, Storing, and Retrieving

Description: GEONET is a database system developed at the Stanford Linear Accelerator Center for the alignment of the Stanford Linear Collider. It features an automated data flow, ranging from data collection using HP110 handheld computers to processing, storing and retrieving data and finally to adjusted coordinates. This paper gives a brief introduction to the SLC project and the applied survey methods. It emphasizes the hardware and software implementation of GEONET using a network of IBM PC/XT's.
Date: August 12, 2005
Creator: Friedsam, Horst; Pushor, Robert; Ruland, Robert & /SLAC
Partner: UNT Libraries Government Documents Department

The SLAC Vertical Comparator for the Calibration of Digital Levels

Description: Digital levels replaced spirit levels in most fields of precise height measurements because of the automation of the height readings. Three manufacturers offer digital levels with a single reading resolution of 10 {micro}m, and for all of them systematic effects are known. In Europe several facilities for system calibration of digital levels using vertical comparators were established within the last decade. However, there still was no system calibration facility in North America. In order to guarantee the accuracy required for the alignment of experiments at the Stanford Linear Accelerator Center (SLAC) a calibration facility for the system calibration of digital levels was built. In this paper the setup of the SLAC vertical comparator is described in detail and its standard uncertainty is derived. In order to perform traditional rod calibration of conventional line-scaled rods, a CCD camera was integrated into the SLAC comparator. The CCD camera setup is also briefly described. To demonstrate the capabilities of the comparator, results of system and rod calibration are shown.
Date: December 6, 2006
Creator: Woschitz, Helmut; U., /Graz; Gassner, Georg; Ruland, Robert & /SLAC
Partner: UNT Libraries Government Documents Department

Alignment without Magnet Fiducials

Description: Presently, the demand for high quality synchrotron radiation is increasing all over the world. One of the fascinating aspects of this novel tool is the broad range of scientific users interested in synchrotron radiation. They come from physics, chemistry, biology, and medicine, to name just a few. Third generation storage which recently became available for users will by far not be able to satisfy all the beam-time requests. In addition, it is also recognized that long-term scientific efficiency and technological success is heavily dependent on ease of access to a home based facility nearby and continuing fine-tuning of all components of a beam line. Based on the high quality user community in Switzerland and their prospective research activities, the Paul Scherrer Institute, in close collaboration with interested research groups from the Swiss universities and the Swiss Federal Institutes of Technology, has worked out a proposal to build an advanced synchrotron light source in Switzerland, which will come into operation in the year 2001. It has been named SLS as acronym for Swiss Light Source.
Date: August 17, 2005
Creator: Ruland, Robert; /SLAC; Mulhaupt, Gottfried; Rohrer, Martin; Wiegand, Peter & /PSI, Villigen
Partner: UNT Libraries Government Documents Department

LCLS Undulator Quadrupole Fiducialization Plan

Description: This note presents the fiducialization plan for the LCLS undulator quadrupoles. The note begins by summarizing the requirements for the fiducialization. A discussion of the measurement equipment is presented, followed by the methods used to perform the fiducialization and check the results. This is followed by the detailed fiducialization plan in which each step is enumerated. Finally, the measurement results and data storage formats are presented. The LCLS is made up of 33 assemblies consisting of an undulator, quadrupole, beam finder wire, and other components mounted on a girder. The components must be mounted in such a way that the beam passes down the axis of each component. In this note, we describe how the ideal beam axis is related to tooling balls on the quadrupole. This step, called fiducialization, is necessary because the ideal beam axis is determined magnetically, whereas tangible objects must be used to locate the quadrupole. The note begins with the list of fiducialization requirements. The laboratory in which the work will be performed and the relevant equipment is then briefly described. This is followed by a discussion of the methods used to perform the fiducialization and the methods used to check the results. A detailed fiducialization plan is presented in which all the steps of fiducialization are enumerated. A discussion of the resulting data files and directory structure concludes the note.
Date: November 24, 2010
Creator: Wolf, Zachary; Levashov, Michael; Lundahl, Eric; Reese, Ed; LeCocq, Catherine; Ruland, Robert et al.
Partner: UNT Libraries Government Documents Department

Control Surveys for Underground Construction of the Superconducting Super Collider

Description: Particular care had to be taken in the design and implementation of the geodetic control systems for the Superconducting Super Collider (SSC) due to stringent accuracy requirements, the demanding tunneling schedule, long duration and large size of the construction effort of the project. The surveying requirements and the design and implementation of the surface and underground control scheme for the precise location of facilities which include approximately 120 km of bored tunnel are discussed. The methodology used for the densification of the surface control networks, the technique used for the transfer of horizontal and vertical control into the underground facilities, and the control traverse scheme employed in the tunnels is described.
Date: August 16, 2005
Creator: Greening, W.J.Trevor; Robinson, Gregory L.; Inc., /Measurment Science; Robbins, Jeffrey S.; Ruland, Robert E. & /SLAC
Partner: UNT Libraries Government Documents Department

Girder Alignment Plan

Description: The girders for the LCLS undulator system contain components which must be aligned with high accuracy relative to each other. The alignment is one of the last steps before the girders go into the tunnel, so the alignment must be done efficiently, on a tight schedule. This note documents the alignment plan which includes efficiency and high accuracy. The motivation for girder alignment involves the following considerations. Using beam based alignment, the girder position will be adjusted until the beam goes through the center of the quadrupole and beam finder wire. For the machine to work properly, the undulator axis must be on this line and the center of the undulator beam pipe must be on this line. The physics reasons for the undulator axis and undulator beam pipe axis to be centered on the beam are different, but the alignment tolerance for both are similar. In addition, the beam position monitor must be centered on the beam to preserve its calibration. Thus, the undulator, undulator beam pipe, quadrupole, beam finder wire, and beam position monitor axes must all be aligned to a common line. All relative alignments are equally important, not just, for example, between quadrupole and undulator. We begin by making the common axis the nominal beam axis in the girder coordinate system. All components will be initially aligned to this axis. A more accurate alignment will then position the components relative to each other, without incorporating the girder itself.
Date: November 18, 2010
Creator: Wolf, Zackary; Ruland, Robert; LeCocq, Catherine; Lundahl, Eric; Levashov, Yurii; Reese, Ed et al.
Partner: UNT Libraries Government Documents Department