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At least 1,189 records · Page 66
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Producing EGS4 Shower Displays with the Unified Graphics System

The EGS4 Code System has been coupled with the SLAC Unified Graphics System in such a manner as to provide a means for displaying showers on UGS77-supported devices. This is most easily accomplished by attaching an auxiliary subprogram package (SHOWGRAF) t o existing EGS4 User Codes and making use of a graphics display or a post-processor code called EGS4PL. SHOWGRAF shower displays directly on interactive ing three-dimensional rotations, translations, may be used to create IBM 5080 color display devices, support- and zoom features, and providing illustration of particle types and energies by color and/or intensity. Alternatively, SHOWGRAF may be used to record a two-dimensional projection of the shower in a device-independent graphics file. The EGS4PL post-processor may then be used to convert this file into device-dependent graphics code for any UGS77-supported device. Options exist within EGS4PL that allow for two-dimensional translations and zoom, for creating line structure to indicate particle types and energies, and for optional display of particles by type. All of this is facilitated by means of the command processor EGS4PL EXEC together with new options (5080 and PDEV) with the standard EGS4IN EXEC routine for running EGS4 interactively under VM/SP.

Cowan, R.↗
DOE OSTI2019

US Contribution to the High Luminosity LHC Upgrade: Focusing Quadrupoles and Crab Cavities

In the early 2000's, the US High Energy Physics community contributing to the Large Hadron Collider (LHC) launched the LHC Accelerator R&D Program (LARP), a long-vision focused R&D program, intended contribute to a quick LHC commissioning and to bring the Nb3Sn and other technologies to a maturity level that would allow applications in HEP machines [1,2]. Around 2015, the technologies developed by LARP, CERN and other institutions were mature enough to allow the spin-off of a major upgrade project to the LHC complex, the High Luminosity LHC (HL-LHC) [3]. This paper will focus on the US contribution to HL-LHC, namely the large-aperture low-β focusing Nb3Sn quadrupoles and the Radio Frequency Dipole (RFD) Crab Cavities, located in close proximity to the ATLAS and CMS experiments. This contribution, called the HL-LHC Accelerator Upgrade Project (HL-LHC AUP), focuses on production of these quadrupoles and cavities by sharing the work among a consortium of US Laboratories (FNAL, LBNL, BNL and SLAC) and Universities and in close connection with the CERN-led HL-LHC Collaboration. The collaboration achieved commonality of specifications and uniformity of performance. Final development of design, construction and first results from the prototypes are described to indicate the status of these critical components for HL-LHC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Opportunities in Machine Learning for Particle Accelerators

Machine learning (ML) is a subfield of artificial intelligence. The term applies broadly to a collection of computational algorithms and techniques that train systems from raw data rather than a priori models. ML techniques are now technologically mature enough to be applied to particle accelerators, and we expect that ML will become an increasingly valuable tool to meet new demands for beam energy, brightness, and stability. The intent of this white paper is to provide a high-level introduction to problems in accelerator science and operation where incorporating ML-based approaches may provide significant benefit. We review ML techniques currently being investigated at particle accelerator facilities, and we place specific emphasis on active research efforts and promising exploratory results. We also identify new applications and discuss their feasibility, along with the required data and infrastructure strategies. We conclude with a set of guidelines and recommendations for laboratory managers and administrators, emphasizing the logistical and technological requirements for successfully adopting this technology. This white paper also serves as a summary of the discussion from a recent workshop held at SLAC on ML for particle accelerators.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

A plan for the development of superconducting Undulator prototypes for LCLS-II and future FELs

Copyright © 2014 CC-BY-3.0 and by the respective authors. Undulators serve as the primary source of radiation for modern storage rings, and more recently for the advent of Free-Electron Lasers (FELs). The performance of future FELs can be greatly enhanced using the much higher magnetic fields of superconducting undulators (SCU) [1]. For example, the LCLS-II hard x-ray undulator can be shortened by up to 70 m using an SCU in place of a PMU (permanent magnet undulator), or its spectral performance can be critically improved when using a similar length. In addition, SCUs are expected to be orders of magnitude less sensitive to radiation dose; a major issue at LCLS-II with its 1-MHz electron bunch rate. We present a funded R&D collaboration between SLAC, ANL, and LBNL, which aims to demonstrate the viability of superconducting undulators for FELs by building, testing, measuring, and tuning two 1.5-m long planar SCU prototypes using two different technologies: NbTi at ANL and Nb3Sn at LBNL. Our goal is to review and reassess the LCLS-II HXR baseline plans (PMU) in July of 2015, after the development and evaluation of both prototypes, possibly in favor of an SCU for LCLS-II.

Emma, P↗
DOE OSTI2014

The MOLLER Experiment: An Ultra-Precise Measurement of the Weak Mixing Angle Using Møller Scattering

The physics case and an experimental overview of the MOLLER (Measurement Of a Lepton Lepton Electroweak Reaction) experiment at the 12 GeV upgraded Jefferson Lab are presented. A highlight of the Fundamental Symmetries subfield of the 2007 NSAC Long Range Plan was the SLAC E158 measurement of the parity-violating asymmetry $A_{PV}$ in polarized electron-electron (M{\o}ller) scattering. The proposed MOLLER experiment will improve on this result by a factor of five, yielding the most precise measurement of the weak mixing angle at low or high energy anticipated over the next decade. This new result would be sensitive to the interference of the electromagnetic amplitude with new neutral current amplitudes as weak as $\sim 10^{-3}\cdot G_F$ from as yet undiscovered dynamics beyond the Standard Model. The resulting discovery reach is unmatched by any proposed experiment measuring a flavor- and CP-conserving process over the next decade, and yields a unique window to new physics at MeV and multi-TeV scales, complementary to direct searches at high energy colliders such as the Large Hadron Collider (LHC). The experiment takes advantage of the unique opportunity provided by the upgraded electron beam energy, luminosity, and stability at Jefferson Laboratory and the extensive experience accumulated in the community after a round of recent successfully completed parity-violating electron scattering experiments

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Status of LCLS - II QA Systems Collaboration for Cyromodule Construction at TJNAF and FNAL

At the Thomas Jefferson National Accelerator Facility (JLab), we are supporting the LCLS-II Project at SLAC. The plan is to build thirty-five 1.3 GHz continuous wave cryomodules, production to be split between JLab and FNAL (Fermilab). This has required a close collaboration between the partner labs, including enhancing our existing quality systems to include this collaboration. This over view describes the current status of the Quality System development as of August 2015, when the partner labs start the assembly of the prototype cryomodules.

McEwen, E. Anne↗
DOE OSTI2015

LCLS-II SRF Cavity Processing Protocol Development and Baseline Cavity Performance Demonstration

The ”Linac Coherent Light Source-II” Project will construct a 4 GeV CW superconducting RF linac in the first kilometer of the existing SLAC linac tunnel. The baseline design calls for 280 1.3 GHz nine-cell cavities with an average intrinsic quality factor Q0 of 2.7·1010 at 2K and 16 MV/m accelerating gradient. The LCLS-II high Q0 cavity treatment protocol utilizes the reduction in BCS surface resistance by nitrogen doping of the RF surface layer, which was discovered originally at FNAL. Cornell University, FNAL, and TJNAF conducted a joint high Q0 R&D program with the goal of (a) exploring the robustness of the N-doping technique and establishing the LCLS-II cavity high Q0 processing protocol suitable for production use, and (b) demonstrating that this process can reliably achieve LCLS-II cavity specification in a production acceptance testing setting. In this paper we describe the LCLS-II cavity protocol and analyze combined cavity performance data from both vertical and horizontal testing at the three partner labs, which clearly shows that LCLS-II specifications were met, and thus demonstrates readiness for LCLS-II cavity production.

Liepe, M.↗
DOE OSTI2020

MEASUREMENT OF Fn 2 /Fp 2 FROM DEEP INELASTIC ELECTRON SCATTERING OFF A=3 MIRROR NUCLEI AT JEFFERSON LAB

This research is part of the Je?erson Lab MARATHON experiment (MeAsurement of the Fn 2 /Fp 2 , d/u RAtios and A = 3 EMC E?ect in Deep Inelastic Electron Scattering Off the Tritium and Helium MirrOr Nuclei). MARATHON is an experiment on electron deep inelastic scattering off the 3H, 3He mirror nuclei. It has extracted, from the measured deep inelastic scattering cross section ratio o? 3H and 3He, the ratio of the neutron to proton inelastic structure functions Fn 2 /Fp 2 . The extraction has taken advantage of the isospin symmetry of the A = 3 mirror nuclei within a novel technique, which avoids the theoretical uncertainties that are present in the SLAC experiments of the 1970s, which used hydrogen and deuterium targets. The experiment was performed using the upgraded 11 GeV beam of the Jefferson Lab electron accelerator, the Hall A Experimental Facility, and a newly designed cryogenic, high-pressure gas target system containing 3H and 3He cells. Electrons scattered o? the gas targets were detected in the two superconducting, high-resolution magnetic spectrometers of Hall A. The cross section data cover the four-momentum transfer squared range 2.0 < Q2 < 14.0 (GeV/c)2, and the Bjorken x scaling variable range 0.19 < x < 0.83. The experiment also measured, for calibration purposes, electron deep inelastic scattering off hydrogen and deuterium at selected kinematics.

Su, Tong↗
DOE OSTI2021

Stochastic Look Ahead Commitment: A Computational Perspective

This presentation gives an overview of a stochastic look ahead commitment (SLAC) problem for managing transmission grid uncertainty in the near- to medium-term (15 minutes to a few hours). We discuss formulation and solution methods, as well as application to transmission system operations.

27 ARPA - Advanced Research Projects Agency-Energy↗
DOE OSTI2021

Dual Energies in the LCLS Copper Linac

For LCLS-II two undulators were installed at SLAC, one for soft and one for hard x-rays. Before the super-conducting linac gets turned on the copper linac is providing beams at 120 Hz to these two beam destinations. The 120 Hz can be split in many different ratios between soft and hard via a pulsed magnet. To get an optimized beam for the quite different photon energies the pulsed linac components like modulators and RF can provide many different beam parameters, mainly energies and bunch lengths for the two undulator lines. How this was implemented with timing setups of triggers and finally after the split the necessary matching of the transverse phase space will be discussed.

Decker, Franz-Josef↗
DOE OSTI2021

Laboratory Measurements of Instrumental Signatures of the LSST Camera Focal Plane

Electro-optical testing and characterization of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) Camera focal plane, consisting of 205 charge-coupled devices (CCDs) arranged into 21 stand-alone Raft Tower Modules (RTMs) and 4 Corner Raft Tower Modules (CRTMs), is currently being performed at the SLAC National Accelerator Laboratory. Testing of the camera sensors is performed using a set of custom-built optical projectors, designed to illuminate the full focal plane or specific regions of the focal plane with a series of light illumination patterns: the crosstalk projector, the flat illuminator projector, and the spot grid projector. In addition to measurements of crosstalk, linearity and full well, the ability to project realistically-sized sources, using the spot grid projector, makes possible unique measurements of instrumental signatures such as deferred charge distortions, astrometric shifts due to sensor effects, and the brighter-fatter effect, prior to camera first light. Here we present the optical projector designs and usage, the electro-optical measurements and how these results have been used in testing and improving the LSST Camera instrumental signature removal algorithms.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Durable Module Materials Consortium (DuraMAT) FY 2021 Annual Report: New Results and a Renewed Consortium

The Durable Module Materials Consortium (DuraMAT) is a multi-lab consortium led by the National Renewable Energy Laboratory, with Sandia National Laboratories, SLAC National Accelerator Laboratory, and Lawrence Berkeley National Laboratory as core research labs. DuraMAT's overarching goal is to discover, develop, de-risk, and enable the rapid commercialization of improved materials, designs, predictive tests, and models for photovoltaic (PV) modules that increase performance, extend lifetime, and enable new applications. Technical results are highlighted throughout this report, and the new projects awarded for FY 2022 address many of the challenges to making 50-year, high-energy-yield modules that were identified in these working groups.

backsheet↗
DOE OSTI2022

200 MV Record Voltage Of vCM And LCLS-II-HE Cryomodules Production Start At Fermilab

The Linac Coherent Light Source (LCLS) is an X-ray science facility at SLAC National Accelerator Laboratory. The LCLS-II project (an upgrade to LCLS) is in the commissioning phase; the LCLS-II-HE (High Energy) project is another upgrade to the facility, enabling higher energy operation. An electron beam is accelerated using superconducting radio frequency (SRF) cavities built into cryomodules. It is planned to build 24 1.3 GHz standard cryomodules and one 1.3 GHz single-cavity Buncher Capture Cavity (BCC) cryomodule for the LCLS-II-HE project. Fourteen of these standard cryomodules and the BCC are planned to be assembled and tested at Fermilab. Procurements for standard cryomodule components are nearing completion. The first LCLS-II-HE cryomodule, referred to as the verification cryomodule (vCM) was assembled and tested at Fermilab. Fermilab has completed the assembly of the second cryomodule. This paper presents LCLS-II-HE cryomodule production status at Fermilab, emphasizing the changes done based on the successes, challenges, mitigations, and lessons learned from LCLS-II; validation of the changes with the excellent vCM results.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

FACET-II

FACET-II is a National User Facility at SLAC National Accelerator Laboratory providing 10 GeV electron beams with µm·rad normalised emittance and peak currents exceeding 100 kA. FACET-II operates as a National User Facility while engaging a broad User community to develop and execute experimental proposals that advance the development of plasma wakefield accelerators. FACET-II is currently commissioned and has started with first experiments. The special features of FACET-II will be shown and first results from the experiments.

Clark, Christine↗
DOE OSTI2013

Resolution Performance of HERA-B Lead-Glass Calorimeters

In preparation of upcoming 12GeV experiments at Thomas Jefferson National Accelerator Facility it is necessary to upgrade existing systems or install new detectors. As part of this effort, an array of lead-glass sampling calorimeters is need for use in the GEP-5 experiment. A sampling calorimeter can be used to determine the energy and spatial position of a high energy particle that enters it while simultaneously stopping the particle. To determine the appropriate construction to meet the needs of upcoming experiments, it was necessary to take an existing model and confirm its energy and position resolution. This model could then be confirmed as an option for the final construction, or used as a starting point to design a better detector. For our test we obtained ten lead-glass calorimeters used in HERA-B and tested them in End Station A at SLAC. I will report on our findings for the HERA-B lead-glass sampling calorimeters. I will cover the results of both the energy and position resolutions as well as the methods used to determine these quantities.

Losada, Anthony↗
DOE OSTI2024

Towards Unlocking Insights from Logbooks Using AI

Electronic logbooks contain valuable information about activities and events concerning their associated particle accelerator facilities. However, the highly technical nature of logbook entries can hinder their usability and automation. As natural language processing (NLP) continues advancing, it offers opportunities to address various challenges that logbooks present. This work explores jointly testing a tailored Retrieval Augmented Generation (RAG) model for enhancing the usability of particle accelerator logbooks at institutes like DESY, BESSY, Fermilab, BNL, SLAC, LBNL, and CERN. The RAG model uses a corpus built on logbook contributions and aims to unlock insights from these logbooks by leveraging retrieval over facility datasets, including discussion about potential multimodal sources. Our goals are to increase the FAIR-ness (findability, accessibility, interoperability, and reusability) of logbooks by exploiting their information content to streamline everyday use, enable macro-analysis for root cause analysis, and facilitate problem-solving automation.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Exclusive η Electro-Production Beam Spin Asymmetry Measurements using CLAS12 at Jefferson Lab

The exploration of nucleon structure and electromagnetic transitions from ground-state to excited-state is a cornerstone of nuclear physics research. Meson electro-production experiments have opened new avenues for investigating these phenomena, particularly in the 12 GeV era at Jefferson Lab with the CLAS12 spectrometer. The ?N final states, accessible only through isospin resonances I = 1/2, provide a unique tool for studying nucleon excitations. By simplifying the analysis and enabling a cleaner extraction of resonance properties compared to the extensively studied ?N final states, ? electroproduction offers a complementary approach to unraveling the structure of excited nucleons. This work presents the first-ever measurement of the beam spin asymmetry (BSA) in exclusive ? electroproduction, covering a previously unexplored kinematic region with 1.6 ? W ? 2.2 GeV. The BSA is extracted from the CLAS12 data using a comprehensive analysis framework that carefully considers the statistical limitations of the data set. The results are compared to predictions from theoretical models, such as the Jülich-Bonn-Washington (JBW) and MAID, as well as compared to previously published cross-section and spin observable results from CLAS and SLAC. Notably, the extracted BSA exhibits discrepancies with the model predictions, highlighting the potential for refining theoretical descriptions of nucleon resonances and their electromagnetic couplings through the incorporation of these new data. The high precision data obtained in this previously unmeasured kinematic region now serve as valuable input for theorists to refine their models.

Illari, Isabella↗