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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Low energy highly charged ion beam facility at Inter University Accelerator Centre: Measurement of the plasma potential and ion energy distributions

A deceleration lens coupled to one of the beam lines of the electron cyclotron resonance based low energy beam facility at Inter University Accelerator Centre is reported. This system is capable of delivering low energy (2.5 eV/q–1 keV/q) highly charged ion beams. The presence of plasma potential hinders the measurements of low energies (<50 eV), therefore, plasma potential measurements have been undertaken using a retarding plate analyzer in unison with the deceleration assembly. The distributions of the ion energies have been obtained and the effect of different source parameters on these distributions is studied.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Performance and physics measurements at protoDUNE-SP

The protoDUNE Single Phase (protoDUNE-SP) TPC is a prototype for the DUNE far detector and it is currently under construction at CERN. It will not only serve as a test-bed for the engineering design and construction techniques but will also provide a set of key measurements for the future DUNE far detector.The new extension of the H4 beam-line at CERN will provide electron, muon and hadron beams with energies in the range of sub-GeV to a few GeV. The data collected during the test beams will be analysed to assess the performance of a state-of-the-art LAr TPC. For such detectors the event reconstruction is challenging and test beam data will allow the performance of the different reconstruction algorithms, which also involve machine-learning techniques, to be benchmarked and improved. Furthermore, important physics measurements are foreseen with protoDUNE-SP. For example, the study of pion interactions in argon using test beams is fundamental to understand some of the processes that will be seen as part of the primary neutrino interactions and which would modify the event signature in the DUNE detectors. ProtoDUNE-SP will provide new measurements of the pion-Ar cross-section, for both positive and negative charges, which will make a vital contribution to improve the current, very limited knowledge of such interactions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Emittance and Phase Space Tomography for the Fermilab Linac

The Fermilab Linac delivers a variable intensity, 400-MeV beam to the MuCool Test Area experimental hall via a beam line specifically designed to facilitate measurements of the Linac beam emittance and properties. A 10 m, dispersion-free and magnet-free straight utilizes an upstream quadrupole focusing triplet in combination with the necessary in-straight beam diagnostics to fully characterize the transverse beam properties. Since the Linac does not produce a strictly elliptical phase space, tomography must be performed on the profile data to retrieve the actual particle distribution in phase space. This is achieved by rotating the phase space distribution using different waist focusing conditions of the upstream triplet and performing a deconvolution of the profile data. Preliminary measurements using this diagnostic section are reported here. These data represent a first-pass measurement of the Linac emittance based on various techniques. It is clear that the most accurate representation of the emittance is given by the 3-profile approach. Future work will entail minimizing the beam spot size on MW5 to test and possibly improve the accuracy of the 2-profile approach. The 95% emittance is {approx} 18{pi} in the vertical and {approx} 13{pi} in the horizontal, which is especially larger than anticipated - 8-10{pi} was expected. One possible explanation is that the entire Linac pulse is extracted into the MTA beamline and during the first few microseconds, the feed forward and RF regulation are not stable. This may result in a larger net emittance observed versus beam injected into Booster, where the leading part of the Linac beam pulse is chopped. Future studies will clearly entail a measurement of the emittance vs. pulse length. One additional concern is that the Linac phase space is most likely aperture-defined and non-elliptical in nature. A non-elliptical phase-space determination would require a more elaborate analysis and provide another explanation of the large emittance measured.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Customized Bayesian optimization for efficient beam tuning at the facility for rare isotope beams

Bayesian optimization (BO) has recently emerged as a powerful approach for on-line beam tuning, and it is rapidly gaining adoption across accelerator facilities due to its flexibility and efficiency in handling complex optimization tasks. At the Facility for Rare Isotope Beams, rapid and reliable tuning is essential to support the delivery of diverse ion species. To improve the practicality of BO in this setting, we implemented several enhancements, including scalarized composite objective construction for multicriteria optimization, asynchronous evaluation for better resource utilization, prior-mean-assisted optimization to accelerate convergence, and a local search strategy for rapid completion of the task. We present the details of these methods, discuss challenges-encountered, and share our experience applying them to specific beam-tuning tasks.

Accelerators & storage rings↗
DOE OSTI2017

Design and simulation study of ultra-fast beam bunches split for three orthogonal planes high-energy electron dynamic radiography

Here a compact three orthogonal planes high-energy electron radiography system was proposed. One of the critical technologies, the ultra-fast beam bunches split from the bunch train are studied. The separated bunches could be transported to the three orthogonal planes of the target for dynamic radiography diagnostics. The key elements of the ultra-fast bunches split system are transverse deflecting cavity (TDC) and the twin septum magnet (TSM). The principle of TDC and TSM are briefly introduced. An example of the beam bunches split system for test experiment (40 MeV electron beam) with TDC and TSM is designed and studied by particle-tracking simulation and it confirms this method is valid and feasible. Especially with TSM, a compact three orthogonal planes radiography system can be realized. The evolution of the beam parameters along the beam line from simulation are investigated. The detailed design of the beam split system and beam dynamics simulation study are presented in this paper.

Zhao, Q. T.↗
DOE OSTI2019

HIGH CURRENT HIGH CHARGE MAGNETIZED AND BUNCHED ELEC-TRON BEAM FROM A DC PHOTOGUN FOR JLEIC COOLER

A high current, high charge magnetized electron beam-line was developed for fast and efficient cooling of ion beams for the proposed Jefferson Lab Electron Ion Col-lider (JLEIC). In this paper, we describe recent achieve-ments that include the generation of picosecond-bunch magnetized beams at average currents up to 28 mA with exceptionally long photocathode lifetime, and independent demonstrations of magnetized beam with high bunch charge up to 700 pC at 10s of kHz repetition rates. In addition, a detailed description of an extremely stable and reliable fiber-based drive laser system that employs a gain-switched master oscillator is presented. These ac-complishments mark important steps toward demonstrat-ing the feasibility of a technically challenging JLEIC cooler design using magnetized beams

Adderley, P.↗
DOE OSTI2012

Beam Position and Phase Monitor - Wire Mapping System

The Los Alamos Neutron Science Center (LANSCE) deploys many cylindrical beam position and phase monitors (BPPM) throughout the linac to measure the beam central position, phase and bunched-beam current. Each monitor is calibrated and qualified prior to installation to insure it meets LANSCE requirements. The BPPM wire mapping system is used to map the BPPM electrode offset, sensitivity and higher order coefficients. This system uses a three-axis motion table to position the wire antenna structure within the cavity, simulating the beam excitation of a BPPM at a fundamental frequency of 201.25 MHz. RF signal strength is measured and recorded for the four electrodes as the antenna position is updated. An effort is underway to extend the systems service to the LANSCE facility by replacing obsolete electronic hardware and taking advantage of software enhancements. This paper describes the upgraded wire positioning system's new hardware and software capabilities including its revised antenna structure, motion control interface, RF measurement equipment and Labview software upgrades. The main purpose of the wire mapping system at LANSCE is to characterize the amplitude response versus beam central position of BPPMs before they are installed in the beam line. The wire mapping system is able to simulate a beam using a thin wire and measure the signal response as the wire position is varied within the BPPM aperture.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Absolute calibration of the DANCE thermal neutron beam using sodium activation

The calculation of the neutron capture cross section as a function of energy in the thermal range requires a precise knowledge of the absolute neutron flux. In this paper a method of calibrating a thermal neutron beam using the controlled activation of sodium is described. Here, the method is applied to the FP-14 Time Of Flight neutron beam line at the Los Alamos Neutron Science Center to calibrate the beam to an uncertainty level of ±5 %.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Application of 3D Code IBSimu for Designing an H{sup -}/D{sup -} Extraction System for the Texas A and M Facility Upgrade

A three dimensional ion optical code IBSimu is being developed at the University of Jyvaeskylae. So far the plasma modelling of the code has been restricted to positive ion extraction systems, but now a negative ion plasma extraction model has been added. The plasma model has been successfully validated with simulations of the Spallation Neutron Source (SNS) ion source extraction both in cylindrical symmetry and in full 3D, also modelling electron beam dumping and ion beam tilt. A filament-driven multicusp ion source has been installed at the Texas A and M University Cyclotron Institute for production of H{sup -} and D{sup -} beams as a part of the facility upgrade. The light ion beams, produced by the ion source, are accelerated with the K150 cyclotron for production and reacceleration of rare isotopes. The extraction system for the ion source was designed with IBSimu. The extraction features a water-cooled puller electrode with a permanent magnet dipole field for dumping the co-extracted electrons and a decelerating Einzel lens for adjusting the beam focusing for further beam transport. The ion source and the puller electrode are tilted at 4 degree angle with respect to the beam line. The extraction system can handle H{sup -} and D{sup -} beams with final beam energies from 5 keV to 15 keV using the same geometry, only adjusting the electrode voltages. So far, 24 {mu}A of H{sup -} and 15 {mu}A of D{sup -} have been extracted from the cyclotron.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

The Naples University 3 MV tandem accelerator

The 3 MV tandem accelerator of the Naples University is used for research activities and applications in many fields. At the beginning of operation (1977) the main utilization was in the field of nuclear physics. Later, the realization of new beam lines allowed the development of applied activities as radiocarbon dating, ion beam analysis, biophysics, ion implantation etc. At present, the availability of different ion sources and many improvements on the accelerator allow to run experiments in a wide range of subjects. An overview of the characteristics and major activities of the laboratory is presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

The very forward CASTOR calorimeter of the CMS experiment

The physics motivation, detector design, triggers, calibration, alignment, simulation, and overall performance of the very forward CASTOR calorimeter of the CMS experiment are reviewed. The CASTOR Cherenkov sampling calorimeter is located very close to the LHC beam line, at a radial distance of about 1 cm from the beam pipe, and at 14.4 m from the CMS interaction point, covering the pseudorapidity range of $-$6.6 $\lt\eta\lt$ $-$5.2. It was designed to withstand high ambient radiation and strong magnetic fields. The performance of the detector in measurements of forward energy density, jets, and processes characterized by rapidity gaps, is reviewed using data collected in proton and nuclear collisions at the LHC.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Experience With Machine Protection Systems At PIP2IT

The PIP-II Injector Test 1 PIP2IT facility accelerator was assembled in multiple stages in 2014 $-$ 2021 to test concepts and components of the future PIPII linac that is being constructed at Fermilab. In its final configuration, PIP2IT accelerated a 0.55 ms x 20 Hz x 2 mA H$-$ beam to 16 MeV. To protect elements of the beam line, a Machine Protection System MPS was implemented and commissioned. The beam was interrupted faster than 10$\mu$s when excessive beam loss was detected. The paper describes the MPS architecture, methods of the loss detection, procedure of the beam interruption, and operational experience at PIP2IT.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Optimizing the front end test stand high performance H{sup -} ion source at RAL

The aim of the front end test stand project is to demonstrate that chopped low energy H{sup -} beams of high quality can be produced. The beam line currently consists of the ion source, a 3 solenoid low energy beam transport and a suite of diagnostics. A brief status report of the radio frequency quadrupole is given. This paper details the work to optimize the ion source performance. A new high power pulsed discharge power supply with greater reliability has been developed to allow long term, stable operation at 50 Hz with a 60 A, 2.2 ms discharge pulse and up to 100 A at 1.2 ms. The existing extraction power supply has been modified to operate up to 22 kV. Results from optical spectroscopy measurements and their application to source optimization are summarized. Source emittances and beam currents of 60 mA are reported.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

The SIRAD irradiation facility at LNL

SIRAD is the irradiation facility at the Tandem XTU accelerator of the INFN National Laboratory of Legnaro (Padova, Italy) dedicated to study radiation effects, both comulative and Single Event, on silicon detectors and microelectronic devices and systems. SIRAD is routinely used by various research groups involved in the development of semiconductor detectors and electronics to be used in radiation hostile environments as experiments at high-energy/high luminosity accelerators or in space, or interested to study the basic radiation damage mechanisms. Single Events Effects (SEE) studies with micrometric resolution can be performed at SIRAD thanks to an Ion Electron Emission Microscope (IEEM) inserted at the end of the beam line. Here we describe the SIRAD facility including the available and future beam characteristics, and the IEEM performances as well as the scientific and technological solutions which have been implemented for its construction.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Mo layer thickness requirement on the ion source back plate for the HNB and DNB ion sources in ITER

All the inner surfaces of the ion sources and the upstream surface of the plasma grid of the ITER neutral beam ion sources are proposed to be coated with molybdenum. This is done to avoid sputtering of the base material (Cu or CuCrZr) by the ions in the source plasma (D{sup +}, D{sub 2}{sup +}, D{sub 3}{sup +} or H{sup +}, H{sub 2}{sup +}, H{sub 3}{sup +}). The sputtering of Mo by the ions in the source plasma is low compared to that from Cu, and the threshold energy for sputtering ∼80 eV) is high compared to the energy of the ions in the source. However the D{sub 2}{sup +}, H{sub 2}{sup +} and D{sup +}, H{sup +} ions backstreaming from the accelerators will have energies that substantially exceed that threshold and it is important that the Mo layer is not eroded such that the base material is exposed to the source plasma. In the case of the HNB, the backstreaming ion power is calculated to be in the order of ∼1 MW, and the average energy of the backstreaming ions is calculated to be ∼300 keV. The ion sources in the HNB beam lines, 40 A 1 MeV D and 46 A 870 keV H beams, are supposed to operate for a period of 2 x 10{sup 7} s. For the DNB, 60 A 100 keV H beams, the corresponding number is 1.4 × 10{sup 6} s considering a beam duty cycle of 3s ON/20s OFF with 5 Hz modulation. The Mo layer on the ion source back plate should be thick enough to survive this operational time. Thickness estimation has been carried out taking into account the sputtering yields (atoms/ion), the energy spectrum of the backstreaming ions and the estimated profiles on the ion source back plate.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Design and Testing of Subsystems for Mo-99 Production

Argonne National Laboratory, in cooperation with Los Alamos National Laboratory, is developing technology with NorthStar Medical Technologies to produce 99 Mo from the γ,n reaction on a 100 Mo target in an electron accelerator. During production runs and thermal testing of the helium-cooled target, it became obvious that a production-scale beam-line configuration would need a collimator to protect the target from accidental beam misplacement or a beam-profile change. A prototype high-power collimator and beam stop were designed and fabricated. Testing indicated that they will be able to operate at full power in the production-scale accelerator.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

The MARS Code System User’s Guide Version 15(2016)

This paper is a user’s guide to the current version of the MARS15 Monte Carlo code. MARS allows inclusive and, in many cases, exclusive simulations of three-dimensional hadronic and electromagnetic cascades and modeling of heavy ion, muon and low energy neutron-photon transport in accelerator, detector, spacecraft and shielding components. Particles can have energies from a fraction of an electronvolt up to about 100 TeV. The code has undergone substantial improvements since the last documented version MARS13(95) and since previous releases of MARS15; all these as well as other specific features of the MARS code system are explained in detail. Descriptions of general input and output with commentary and recommendations are given. Examples are given for running the program with distributed sources, complex compounds, arbitrary geometries, and magnetic fields. A built-in graphical-user interface allows the visualization and detailed analysis of the geometry description. Enhanced options are described for the MARS code being coupled with: the DPMJET hadron event generator, the MCNP code for low-energy neutron transport, the ANSYS system for thermal and stress analysis, physics analysis and graphics packages, the MAD accelerator lattice description via a universal MAD-MARS beam line builder, the STRUCT program for tracking particles in accelerator lattices with beam loss recording, the DETRA code for nuclide decay and transmutation calculations, the EGS5 code for precise modeling of low-energy electromagnetic showers, and the ROOT system for description and visualization of arbitrary geometries. Use of the code in a multistage mode, coupled with event generators (DPMJET), with the STRUCT program for tracking particles in accelerator lattices with beam loss recording, and with physics analysis and graphics packages is demonstrated with typical input and output examples.

43 PARTICLE ACCELERATORS↗