1,730,692 research outputs found
SLAC Cosmic Ray Telescope Facility
No full textSLAC does not have a test beam for the HEP detector development at present. We have therefore created a cosmic ray telescope (CRT) facility, which is presently being used to test the FDIRC prototype. We have used it in the past to debug this prototype with the original SLAC electronics before going to the ESA test beam. Presently, it is used to test a new waveform digitizing electronics developed by the University of Hawaii, and we are also planning to incorporate the new Orsay TDC/ADC electronics. As a next step, we plan to put in a full size DIRC bar box with a new focusing optics, and test it together with a final SuberB electronics. The CRT is located in building 121 at SLAC. We anticipate more users to join in the future. This purpose of this note is to provide an introductory manual for newcomers
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S-Band Loads for SLAC Linac
No full textThe S-Band loads on the current SLAC linac RF system were designed, in some cases, 40+ years ago to terminate 2-3 MW peak power into a thin layer of coated Kanthal material as the high power absorber [1]. The technology of the load design was based on a flame-sprayed Kanthal wire method onto a base material. During SLAC linac upgrades, the 24 MW peak klystrons were replaced by 5045 klystrons with 65+ MW peak output power. Additionally, SLED cavities were introduced and as a result, the peak power in the current RF setup has increased up to 240 MW peak. The problem of reliable RF peak power termination and RF load lifetime required a careful study and adequate solution. Results of our studies and three designs of S-Band RF load for the present SLAC RF linac system is discussed. These designs are based on the use of low conductivity materials
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Development of Modulator Pulse Stability Measurement Device and Test Results at SLAC
No full textIn this paper, the development of a pulse stability measurement device is presented. The measurement accuracy is better than 250uV, about 4.2ppm of a typical 60V input pulse. Pulse signals up to +/- 80V peak can be measured. The device works together with an oscilloscope. The primary function of the measurement device is to provide a precision offset, such that variations in the flattop of the modulator voltage pulse can be accurately resolved. The oscilloscope records the difference between the pulse flattop and the reference for a series of waveforms. The scope math functions are utilized to calculate the rms variations over the series. The frequency response of the device is characterized by the measured cutoff frequency of about 6.5MHz. In addition to detailing the design and calibration of the precision pulse stability device, measurements of SLAC line-type linac modulators and recently developed induction modulators will be presented. Factors affecting pulse stability will be discussed
Physicists Thriving with Paperless Publishing
No full textThe Stanford Linear Accelerator Center (SLAC) and Deutsches Elektronen Synchrotron (DESY) libraries have been comprehensively cataloguing the High Energy Particle Physics (HEP) literature online since 1974. The core database, SPIRES-HEP, now indexes over 400,000 research articles, with almost 50% linked to fulltext electronic versions (this site now has over 15 000 search hits per day). This database motivated the creation of the first site in the United States for the World-Wide Web at SLAC. With this database and the invention of the Los Alamos E-print archives in 1991, the HEP community pioneered the trend to "paperless publishing" and the trend to paperless access; in other words, the "virtual library." We examine the impact this has had both on the way scientists research and on paper-based publishing. The standard of work archived at Los Alamos is very high. 70% of papers are eventually published in journals and another 20% are in conference proceedings. As a service to authors, the SPIRES-HEP collaboration has been ensuring that as much information as possible is included with each bibliographic entry for a paper. Such metadata can include tables of the experimental data that researchers can easily use to perform their own analyses as well as detailed descriptions of the experiment, citation tracking, and links to full-text documents
HISTORIANS AT WORK IN THE SLAC ARCHIVES: An Archivist’s Perspective
No full textActive collecting of the archives of the SLAC National Accelerator Laboratory – as well as of other US national laboratories – began in earnest in the late twentieth century as a result of the interest and agitation by both Historians of Science and Archivists. This paper examines the use and dissemination of knowledge of the histories of the US science laboratories as exemplified by the SLAC Archives and History Office (AHO) experience. We find that the development of the SLAC AHO program has been and continues to be propelled by ongoing exchanges between the two disciplines, shaped by their sometimes limited understanding of each other’s goals, methodologies, and constraints, and by the two disciplines ’ relationships to the records-creating scientists
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A New Control Room for SLAC Accelerators
No full textWe are planning to construct a new control room at SLAC to unify and improve the operation of the LCLS, SPEAR3, and FACET accelerator facilities, and to provide the space and flexibility needed to support the LCLS-II and proposed new test beam facilities. The existing control rooms for the linac and SPEAR3 have been upgraded in various ways over the last decade, but their basic features have remained unchanged. We propose to build a larger modern Accelerator Control Room (ACR) in the new Research Support Building (RSB) which is currently under construction at SLAC. Shifting the center of control for the accelerator facilities entails both technical and administrative challenges. In this paper, we describe the history, concept, and status of this project
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SLAC Next-Generation High Availability Power Supply
No full textSLAC recently commissioned forty high availability (HA) magnet power supplies for Japan's ATF2 project. SLAC is now developing a next-generation N+1 modular power supply with even better availability and versatility. The goal is to have unipolar and bipolar output capability. It has novel topology and components to achieve very low output voltage to drive superconducting magnets. A redundant, embedded, digital controller in each module provides increased bandwidth for use in beam-based alignment, and orbit correction systems. The controllers have independent inputs for connection to two external control nodes. Under fault conditions, they sense failures and isolate the modules. Power supply speed mitigates the effects of fault transients and obviates subsequent magnet standardization. Hot swap capability promises higher availability and other exciting benefits for future, more complex, accelerators, and eventually the International Linear Collider project
Facet: The new user facility at SLAC
No full textFACET (Facility for Advanced Accelerator and Experimental Tests) is a new User Facility at SLAC National Accelerator Laboratory. Its high power electron and positron beams make it a unique facility, ideal for beam-driven Plasma Wakefield Acceleration studies. The first 2 km of the SLAC linac produce 23 GeV, 3.2 nC electron and positron beams with short bunch lengths of 20 μm. A final focusing system can produce beam spots 10 μm wide. User-aided Commissioning took place in summer 2011 and FACET will formally come online in early 2012. We present the User Facility, the current features, planned upgrades and the opportunities for further experiments. Copyright © 2011 by IPAC'11/EPS-AG
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LLRF System Upgrade for the SLAC Linac
No full textThe Linac Coherent Light Source (LCLS) at SLAC is in full user operation and has met the stability goals for stable lasing. The 250pC bunch can be compressed to below 100fS before passing through an undulator. In a new mode of operation a 20pC bunch is compressed to about 10fS. Experimenters are regularly using this shorter X-ray pulse and getting pristine data. The 10fS bunch has timing jitter on the order of 100fS. Physicists are requesting that the RF system achieve better stability to reduce timing jitter. Drifts in the RF system require longitudinal feedbacks to work over large ranges and errors result in reduced performance of the LCLS. A new RF system is being designed to help diagnose and reduce jitter and drift in the SLAC linac
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SLAC Linac Preparations for FACET
No full textThe SLAC 3km linear electron accelerator has been cut at the two-thirds point to provide beams to two independent programs. The last third provides the electron beam for the Linac Coherent Light Source (LCLS), leaving the first two-thirds available for FACET, the new experimental facility for accelerator science and test beams. In this paper, we describe this separation and projects to prepare the linac for the FACET experimental program
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