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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Detection efficiency of microchannel plates for e{sup −} and π{sup −} in the momentum range from 17.5 to 345 MeV/c

High-energy e{sup –} and π{sup –} were measured by the multichannel plate (MCP) detector at the PiM1 beam line of the High Intensity Proton Accelerator Facilities located at the Paul Scherrer Institute, Villigen, Switzerland. The measurements provide the absolute detection efficiencies for these particles: 5.8% ± 0.5% for electrons in the beam momenta range 17.5–300 MeV/c and 6.0% ± 1.3% for pions in the beam momenta range 172–345 MeV/c. The pulse height distribution determined from the measurements is close to an exponential function with negative exponent, indicating that the particles penetrated the MCP material before producing the signal somewhere inside the channel. Low charge extraction and nominal gains of the MCP detector observed in this study are consistent with the proposed mechanism of the signal formation by penetrating radiation. A very similar MCP ion detector will be used in the Neutral Ion Mass (NIM) spectrometer designed for the JUICE mission of European Space Agency (ESA) to the Jupiter system, to perform measurements of the chemical composition of the Galilean moon exospheres. The detection efficiency for penetrating radiation determined in the present studies is important for the optimisation of the radiation shielding of the NIM detector against the high-rate and high-energy electrons trapped in Jupiter’s magnetic field. Furthermore, the current studies indicate that MCP detectors can be useful to measure high-energy particle beams at high temporal resolution.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Estimating Beam-Target Heating

At Los Alamos National Laboratory, two high-current linear induction accelerators (LIAs) are used to produce bremsstrahlung source spots for flash radiography of high-explosive driven hydrodynamic experiments at the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility. Measurements of the electron-beam current density profile are valuable for understanding the beam dynamics in order to improve the quality of the radiography source spot. A technique commonly used at DARHT is to image the profile in Cerenkov or Optical Transition Radiation (OTR) light created by the beam striking a thin target inserted into the beam line. Target materials include aluminized dielectrics and titanium foils for OTR, and fused silica wafers for Cerenkov radiation. A practical complication with this technique is heating of the target by the electron beam. If the beam density is too great, the target can be destroyed. Moreover, even if the beam density is kept low enough to be nondestructive, the beam can heat the target to a high enough temperature to desorb gas from the surface. In that case, direct impact ionization of the gas by beam electrons can partially neutralize the beam, causing it to over-focus, thereby spoiling the data, if not destroying the target. The purpose of this note is to review some of the fundamental physics of electron beam heating in order to provide some elementary guidance for design of these imaging experiments to avoid overheating the target. Some specific examples for materials that we often use for imaging targets and beam-target experiments are provided.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Study of the Variation of Transverse Voltage in the 4 Rod Crab Cavity for LHC

The planned high luminosity upgrade to LHC will utilise crab cavities to rotate the beam in order to increase the luminosity in the presence of a finite crossing angle. A compact design is required in order for the cavities to fit between opposing beam-lines. In this paper we discuss we discuss one option for the LHC crab cavity based on a 4 rod TEM deflecting cavity. Due to the large transverse size of the LHC beam the cavity is required to have a large aperture while maintaining a constant transverse voltage across the aperture. The cavity has been optimised to minimise the variation of the transverse voltage while keeping the peak surface electric and magnetic fields low for a given kick. This is achieved while fitting within the strict design space of the LHC. The variation of deflecting voltage across the aperture has been studied numerically and compared with numerical and analytical estimates of other deflecting cavity types. Performance measurements an aluminium prototype of this cavity are presented and compared to the simulated design.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Baby MIND Experiment Construction Status

Baby MIND is a magnetized iron neutrino detector, with novel design features, and is planned to serve as a downstream magnetized muon spectrometer for the WAGASCI experiment on the T2K neutrino beam line in Japan. One of the main goals of this experiment is to reduce systematic uncertainties relevant to CP-violation searches, by measuring the neutrino contamination in the anti-neutrino beam mode of T2K. Baby MIND is currently being constructed at CERN, and is planned to be operational in Japan in October 2017.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

SU-E-J-142: Prompt Gamma Emission Measurements From a Passively Scattered Proton Beam On Targets Containing 16O, 12C and 14N

Purpose: To measure the prompt gamma emission from the important elements found in tissue ({sup 16}O,{sup 12}C and {sup 14}N) in a clinical passive-scatter treatment environment. Methods: The targets (composed of water, Perspex, graphite and liquid nitrogen) were irradiated with a 200 MeV passive-scatter proton beam and the discrete prompt gamma energy spectra was detected by a high resolution 2′ × 2′ LaBr. detector. In order to reduce the high level of radiation produced by the beam line elements, the detector was surrounded by 10 cm of lead to attenuate the scattered gamma-rays entering the detector with an extra 5 cm thick layer of lead added along the beam direction. A 10 cm thick collimator with a 5 cm × 10 cm rectangular opening was also used. Results: The prompt gamma peaks at 6.13 MeV and 4.44 MeV were clearly identified as a Result of the inelastic nuclear reaction between the protons and the 16O atoms found in the water target. The 6.13 MeV peak was 5% higher than the peak at 4.44 MeV for the water target. The 4.44 MeV peak was the only identified emission in the prompt gamma energy spectra from the graphite target ({sup 12}C). The expected 2.313 MeV peak form the{sup 14}N (liquid nitrogen target) was identified, but the other expected {sup 14}N peaks could not be resolved. Conclusion: Prompt gamma measurements with a passive-scatter proton beam are possible, but the presence of a high amount of background radiation from the patient final collimator presents a challenge at the treatment isocenter. The prominent prompt gamma peaks at 6.13 MeV and 4.44 MeV were identified from the water, Perspex and graphite targets. The prompt gammas from the liquid nitrogen target were difficult to see, but may not be significant in the in-vivo verification process.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Neutron productions in the fragmentation of relativistic heavy nuclei and formation of a beam of high-energy neutrons

The production of quasimonoenergetic high-energy neutrons at zero angle (0°) in the spallation of relativistic heavy nuclei is discussed by considering the example of the interaction of lead nuclei with light target nuclei. It is shown that this process can be used to generate a beam of high-energy neutrons at existing heavy ion accelerators. At the same time, itmay lead to the appearance of a parasitic neutron beam because of the interaction of the heavy-ion beam used with beam line and experimental setup materials.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Radiation and Thermal Analysis of Superconducting Quadrupoles in the Interaction Region of Linear Collider

Radiation heat deposition in the superconducting magnets of the Interaction Region (IR) of a linear collider can be a serious issue that limits the magnet operating margins and shortens the material lifetime. Radiation and thermal analyses of the IR quadrupoles in the incoming and extraction beam lines of the ILC are performed in order to determine the magnet limits. This paper presents an analysis of the radial, azimuthal and longitudinal distributions of heat deposition in the incoming and disrupted beam doublets. Operation margins of the magnets based on NbTi superconductor are calculated and compared. The radiation and thermal analysis of the ILC IR quadrupoles based on Rutherford type cables was performed. It was found that the peak radiation heat deposition takes place in the second extraction quadrupole QFEX2. The maximum power density in the coil is {approx}17mW/g. This is rather high, comparing to the proton machines (LHC). However, the fast radial decay of the heat deposition together with the high thermal conductivity of the Rutherford type cable limits the coil temperatures to a moderate level. It was determined that both 2-layer and 4-layer QFEX2 magnet designs have thermal margins of a factor of {approx}4 at the nominal gradient of 31.3 T/m. Because of the large margins, these magnets can easily accommodate possible changes in the IR optics and heat deposition levels.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Development of a machine protection system for the Superconducting Beam Test Facility at Fermilab

Fermilab's Superconducting RF Beam Test Facility currently under construction will produce electron beams capable of damaging the acceleration structures and the beam line vacuum chambers in the event of an aberrant accelerator pulse. The accelerator is being designed with the capability to operate with up to 3000 bunches per macro-pulse, 5Hz repetition rate and 1.5 GeV beam energy. It will be able to sustain an average beam power of 72 KW at the bunch charge of 3.2 nC. Operation at full intensity will deposit enough energy in niobium material to approach the melting point of 2500 C. In the early phase with only 3 cryomodules installed the facility will be capable of generating electron beam energies of 810 MeV and an average beam power that approaches 40 KW. In either case a robust Machine Protection System (MPS) is required to mitigate effects due to such large damage potentials. This paper will describe the MPS system being developed, the system requirements and the controls issues under consideration.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

LONGITUDINAL LASER WIRE AT SNS

This paper describes a longitudinal H- beam profile scanner that utilizes laser light to detach convoy electrons and an MCP to collect and measure these electrons. The scanner is located in MEBT with H- energy of 2.5MeV and an RF frequency 402.5MHz. The picosecond pulsed laser runs at 80.5MHz in sync with the accelerator RF. The laser beam is delivered to the beam line through a 30m optical fiber. The pulse width after the fiber transmission measures about 10ps. Scanning the laser phase effectively allows measurements to move along ion bunch longitudinal position. We are able to reliably measure production beam bunch length with this method. The biggest problem we have encountered is background signal from electrons being stripped by vacuum. Several techniques of signal detection are discussed.

Aleksandrov, Alexander V↗
DOE OSTI2011

Conceptual Design of the Project-X 1.3 GHz, 3-8 GeV Pulsed Linac

The Project-X, a multi-MW proton source, is under development at Fermilab. It enables a Long Baseline Neutrino Experiment via a new beam line pointed to DUSEL in Lead, South Dakota, and a broad suite of rare decay experiments. The facility co ntains 3-GeV 1-mA CW superconducting linac. In the second stage of about 5% of the H- beam is accelerated up to 8 GeV in a 1.3 GHz SRF pulse linac to Recycler/Main Injector. In order to mitigate the problem with the stripping foil heating during injection to the Main Injector, the pulses with higher current are accelerated in CW linac together with 1 mA beam for further acceleration in the pulse linac. The optimal current in the pulse linac is discussed as well as limitations that determine it's selection . A concept design of the pulse linac is described. The lattice design is presented as well as RF stability analysis. The necessity of the HOM couplers is discussed also.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

SU-F-T-207: Does the Greater Flexibility of Pencil Beam Scanning Reduce the Need for a Proton Gantry?

Purpose: Gantry-less proton treatment facility could lower the capital cost of proton therapy. This study investigates the dosimetric feasibility of using only coplanar pencil beam scanning (PBS) beams for those patients who had beam angles that would not have been deliverable without the gantry. Those coplanar beams are implemented on gantry-less horizontal beam-line with patients in sitting or standing positions. Methods: We have selected ten patients (seven head-and-neck, one thoracic, one abdominal and one pelvic case) with clinically delivered double scattering (DS) or PBS treatment plans with beam angles that were challenging to achieve without a gantry. After removing these beams angles, PBS plans were optimized for gantry-less intensity modulated proton therapy (IMPT) or single field optimization (SFO) with multi-criteria optimization (MCO). For head-and-neck patients who were treated by DS, we generated PBS plans with non-coplanar beams for comparison. Dose-volume-histograms (DVHs), target homogeneity index (HI), mean dose, D-2 and D-98 were reported. Robustness analysis was performed with ±2.5 mm setup errors and ±3.5% range uncertainties for three head-and-neck patients. Results: PBS-gantry-less plans provided more homogenous target coverage and significant improvements on organs-at-risk (OARs) sparing, compared to passive scattering treatments with a gantry. The PBS gantry-less treatments reduced the HI for target coverage by 1.3% to 47.2%, except for a suprasellar patient and a liver patient. The PBS-gantry-less plans reduced the D-mean of OARs by 3.6% to 67.4%. The PBS-gantry plans had similar target coverage and only marginal improvements on OAR sparing as compared to the PBS-gantry-less plans. These two PBS plans also had similar robustness relative to range uncertainties and setup errors. Conclusion: The gantry-less plans have with less mean dose to OARs and more homogeneous target coverage. Although the PBS-gantry plans have slightly improved target coverage and OARs sparing, the overall benefit of having a gantry to provide non-coplanar beams is debatable.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Effects of Electron Irradiation on Candidate Materials for Target Window in Accelerator-Driven Molybdenum-99 Production

NorthStar Medical technologies is planning to produce Mo-99 through the photo-nuclear reaction Mo-100 (γ,n) Mo-99 utilizing multiple high-power electron accelerators. In this approach, the production target consists of multiple thin disks of metal Mo-100 cooled by helium gas at high (300–400 psi) pressure [4]. The cost of enriched Mo-100 is on the order of $500 - 1,000 per gram, which makes a smaller target desirable and requires achieving the highest possible electron flux on the target. The heat deposition in the entrance window limits the maximum flux because the window separates the vacuum in the accelerator beam line from the high-pressure helium in the target and is only cooled on one side by the helium flow. Because the window is continuously under stress from the helium pressure and the heat from the electron beam, it is desirable to estimate a lifetime for the window and develop a replacement schedule for the target holder. Such an estimate requires the ability to predict changes in the window material properties under electron irradiation. Candidate materials for the Mo-99 production target window are Inconel 718, 250 maraging steel, and beryllium. These materials encompass a wide range of thermal conductivity, thermal expansion coefficients, Young’s modulus, tensile strength and tensile ductility. The Mo-99 target window is subjected to internal pressure from the helium coolant and thermal stresses. The operating conditions and relative advantages of each material have been described previously [1]. The current work investigates the effects of electron irradiation on the tensile properties of these materials. Axial tensile tests were conducted with electron-irradiated samples and results were compared to baseline results generated for as-fabricated materials.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Resistive Wall Simulations with LAMDA

The prospect for a new downstream transport (DST) beam line for multipulse target testing (MPTL) has raised questions about the resistive-wall instability, which has been theoretically shown to couple between the multiple pulses in a pulse train. Recent upgrades to computer operating systems and the LAMDA beam dynamics code mandate that the code be revalidated before using to explore MPTL parameters. This note is a brief account of the revalidation of LAMDA for resistive wall problems.

43 PARTICLE ACCELERATORS↗
NASA NTRS2008

Synchrotron X-Ray Diffraction Studies of Olivine from Comet Wild 2

We have analyzed a collection of the Comet Wild 2 coma grains returned by the NASA Stardust Mission, using micro-area Laue diffraction equipment. The purpose of the diffraction experiment is to permit the structure refinement of olivine including site occupancies. In addition to the intrinsic importance of the olivine structures for revealing the thermal history of Wild 2 materials, we wish to test reports that olivine recovered after hypervelocity capture in silica aerogel has undergone a basic structural change due to capture heating [1]. The diffraction equipment placed at beam line BL- 4B1 of PF, KEK was developed with a micropinhole and an imaging plate (Fuji Co. Ltd.) using the Laue method combined with polychromatic X-ray of synchrotron radiation operated at energy of 2.5 GeV. The incident beam is limited to 1.6 m in diameter by a micropinhole set just upstream of the sample [2, 3]. It is essential to apply a microbeam to obtain diffracted intensities with high signal to noise ratios. This equipment has been successfully applied to various extraterrestrial materials, including meteorites and interplanetary dust particles [4]. The Laue pattern of the sample C2067,1,111,4 (Fig. 1) was successfully taken on an imaging plate after a 120 minute exposure (Fig. 2).

Source record↗
DOE OSTI2024

Measurement and modeling of beam transport in the FODO line of the Spallation Neutron Source Beam Test Facility

Ongoing studies at the Spallation Neutron Source (SNS) Beam Test Facility (BTF) seek to understand and model bunch dynamics in a high-power LINAC front-end. The BTF has recently been upgraded with a reconfiguration from a U-shaped line to a Straight line. We report the current state of model benchmarking, with a focus on RMS beam sizes within the FODO line. The beam measurement is obtained via three camera/screen pairs in the FODO line. This presentation discusses the methodology and results of this measurement.

Thompson, Trent↗
DOE OSTI2015

The ArgoNeuT Experiment

The ArgoNeuT (Argon Neutrino Test) Experiment ran on the NuMI beam line at the Fermi National Accelerator Laboratory, from Sep 2009 to Feb 2010. It is the first stage of the US R and D effort on using Liquid Argon Time Projection Chambers (LArTPCs) as neutrino detectors. ArgoNeuT has collected thousands of beam neutrino events in the 0.1 -10 GeV energy range during its run and, apart from fulfilling its R and D goals, is now publishing physics results, including the first measurement of the inclusive muon neutrino charged current differential cross sections on argon. These proceedings will present these results, together with the perspectives for ongoing and future analyses, as well as ideas for running the detector in a test beam of charged particles.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

First Calorimetric Energy Reconstruction of Beam Events with ARAPUCA Light Detector in ProtoDUNE-SP

ProtoDUNE Single Phase at CERN is the large scale prototype for the far detector of the future DUNE experiment. ProtoDUNE is in stable operation since Oct. 2018 at the CERN Neutrino Platform. Test beam data in the energy range of sub-GeV to a few GeV were collected in fall 2018 providing a set of key measurements. Particles (electrons, protons, pions, muons and kaons) are identified combining information from a set of beam-line detectors (Time of Flight, Cherenkov) and TPC reconstruction. Three different technologies are implemented in the protoDUNE photon detector system (PDS). Results from the ARAPUCA response, one of the PDS components, are presented providing first calorimetric energy measurements and particle ID of beam events from LAr scintillation light signals.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurement of K + production cross section by 8 GeV protons using high energy neutrino interactions in the SciBooNE detector

The SciBooNE Collaboration reports K + production cross section and rate measurements using high energy daughter muon neutrino scattering data off the SciBar polystyrene (C 8 H 8 ) target in the SciBooNE detector. The K + mesons are produced by 8 GeV protons striking a beryllium target in Fermilab Booster Neutrino Beam line (BNB). Using observed neutrino and antineutrino events in SciBooNE, we measure d 2 σ/dpdΩ = (5.34 ±0.76) mb/(GeV/c x sr) for p + Be =K + + X at mean K + energy of 3.9 GeV and angle (with respect to the proton beam direction) of 3.7 degrees, corresponding to the selected K + sample. Compared to Monte Carlo predictions using previous higher energy K + production measurements, this measurement, which uses the NUANCE neutrino interaction generator, is consistent with a normalization factor of 0.85 ± 0.12. This agreement is evidence that the extrapolation of the higher energy K + measurements to an 8 GeV beam energy using Feynman scaling is valid. This measurement reduces the error on the K + production cross section from 40% to 14%.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗