scholarly journals Light yield of cold undoped CsI crystal down to 13 keV and the application of such crystals in neutrino detection

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Keyu Ding ◽  
Dmitry Chernyak ◽  
Jing Liu
Keyword(s):  
Energy Range ◽  
Neutron Source ◽  
National Laboratory ◽  
Light Yield ◽  
Radioactive Source ◽  
Experimental Result ◽  
Spallation Neutron Source ◽  
Oak Ridge ◽  
Neutrino Detection ◽  
Electron Equivalent

AbstractThe light yield of an undoped CsI crystal at about 77 Kelvin was measured to be $$33.5 \, \pm \, 0.7$$ 33.5 ± 0.7  photo-electrons (PE) per keV electron-equivalent (keVee) in the energy range of [13, 60] keVee using X and $$\gamma $$ γ -rays from an $$^{241}$$ 241 Am radioactive source. Based on this experimental result, the performance of 10 kg cryogenic inorganic scintillating crystals coupled to SiPM arrays to probe non-standard neutrino interactions through the detection of coherent elastic neutrino-nucleus scatterings at the spallation neutron source, Oak Ridge National Laboratory, was examined in detail.

scholarly journals The Macromolecular Neutron Diffractometer MaNDi at the Spallation Neutron Source

2015 ◽  
Vol 48 (4) ◽  
pp. 1302-1306 ◽  
Author(s):  
Leighton Coates ◽  
Matthew J. Cuneo ◽  
Matthew J. Frost ◽  
Junhong He ◽  
Kevin L. Weiss ◽  
...  
Keyword(s):  
Data Collection ◽  
Single Crystals ◽  
Neutron Source ◽  
Diffraction Data ◽  
National Laboratory ◽  
Spallation Neutron Source ◽  
Oak Ridge ◽  
Neutron Diffractometer ◽  
Macromolecular Systems ◽  
Neutron Time

The Macromolecular Neutron Diffractometer (MaNDi) is located on beamline 11B of the Spallation Neutron Source at Oak Ridge National Laboratory. The instrument is a neutron time-of-flight wavelength-resolved Laue diffractometer optimized to collect diffraction data from single crystals. The instrument has been designed to provide flexibility in several instrumental parameters, such as beam divergence and wavelength bandwidth, to allow data collection from a range of macromolecular systems.

scholarly journals High-resolution neutron time-of-flight measurements for light water at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory

2020 ◽  
Vol 239 ◽  
pp. 14005
Author(s):  
Luiz Leal ◽  
Vaibhav Jaiswal ◽  
Alexander I. Kolesnikov
Keyword(s):  
Experimental Data ◽  
Neutron Source ◽  
National Laboratory ◽  
Operating Conditions ◽  
Spallation Neutron Source ◽  
Light Water ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory ◽  
Thermal Scattering ◽  
Reactor Operating

Series of light water inelastic neutron scattering experiments have been made at the Oak Ridge National Laboratory (ORNL), Spallation Neutron Source (SNS) covering temperatures ranging from 295 K to 600 K and pressures of 1 bar and 150 bar. The temperatures and pressures ranges correspond to that of pressurized light water reactors. The inelastic scattering measurements will help the development of light water thermal scattering kernels, also known as S (α,β) thermal scattering law (TSL), in a consistent fashion given the amount and the quality of the measured data. Light water thermal scattering evaluations available in existing nuclear data libraries have certain limitations and pitfalls. This paper introduces the state of the art of the light water thermal scattering cross-section data not only for room temperature but as well as for reactor operating temperatures, i.e. 550 - 600 K. During the past few years there has been a renewed interest in re-investigating the existing TSL models and utilize the recent experimental data or perform molecular dynamics simulations. It should be pointed out that no single TSL evaluation is based entirely on experimental data and one has to rely on TSL models or a combination of both. New TOF measurement of light water at the SNS, with a detailed description of the experimental setup, measurement conditions, and the associated foreseen results is presented in this paper. The analysis of the experimental data would help in validating the existing approach based on old experimental data or based on molecular dynamic simulations using classical water models, knowledge of which is very important to generate TSL libraries at reactor operating conditions.

The macromolecular neutron diffractometer (MaNDi) at the Spallation Neutron Source, Oak Ridge: enhanced optics design, high-resolution neutron detectors and simulated diffraction

2010 ◽  
Vol 43 (3) ◽  
pp. 570-577 ◽  
Author(s):  
L. Coates ◽  
A. D. Stoica ◽  
C. Hoffmann ◽  
J. Richards ◽  
R. Cooper
Keyword(s):  
High Resolution ◽  
Neutron Source ◽  
National Laboratory ◽  
High Energy ◽  
Neutron Guide ◽  
Spallation Neutron Source ◽  
Neutron Detectors ◽  
Spectral Window ◽  
Oak Ridge ◽  
Neutron Diffractometer

The macromolecular neutron diffractometer MaNDi is currently under construction at the first target station of the Spallation Neutron Source at Oak Ridge National Laboratory. This instrument will collect neutron diffraction data from small single crystals (0.1–1 mm3) with lattice constants between 100 and 300 Å, as well as data from less well ordered systems such as fibers. A focusing neutron guide has been designed to filter the high-energy neutron component of the spectrum and to provide a narrow beam with a wide spectral window and angular divergence almost insensitive to neutron wavelength. The system includes a final interchangeable section of neutron guide and two slits, which enable tuning of the horizontal and vertical beam divergence between 0.12 and 0.80° (full width at half-maximum) at the sample position. This allows the trading of intensity for resolution, depending on the scientific requirements. Efforts to enhance and develop suitable high-resolution neutron detectors at an affordable price are also discussed. Finally, the parameters of the neutron guide and detectors were used to simulate diffraction from a large unit cell.

scholarly journals Atomic pair distribution function analysis from the ARCS chopper spectrometer at the Spallation Neutron Source

2009 ◽  
Vol 42 (4) ◽  
pp. 724-725 ◽  
Author(s):  
E. S. Božin ◽  
P. Juhás ◽  
W. Zhou ◽  
M. B. Stone ◽  
D. L. Abernathy ◽  
...  
Keyword(s):  
Neutron Source ◽  
Powder Diffraction ◽  
Function Analysis ◽  
National Laboratory ◽  
Distribution Functions ◽  
Spallation Neutron Source ◽  
Los Alamos National Laboratory ◽  
Oak Ridge ◽  
Atomic Pair Distribution Function ◽  
Atomic Pair

Neutron powder-diffraction-based atomic pair distribution functions (PDFs) are reported from the new wide-angular-range chopper spectrometer ARCS at the Spallation Neutron Source at Oak Ridge National Laboratory. The spectrometer was run in white-beam mode with no Fermi chopper. The PDF patterns of Ni and Al2O3were refined using the PDFfit method and the results compared with data collected at the NPDF diffractometer at Los Alamos National Laboratory. The resulting fits are of high quality, demonstrating that quantitatively reliable powder diffraction data can be obtained from ARCS when operated in this configuration.

scholarly journals Event-based processing of neutron scattering data at the Spallation Neutron Source

2018 ◽  
Vol 51 (3) ◽  
pp. 616-629 ◽  
Author(s):  
Garrett E. Granroth ◽  
Ke An ◽  
Hillary L. Smith ◽  
Pamela Whitfield ◽  
Joerg C. Neuefeind ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Neutron Source ◽  
National Laboratory ◽  
Scattering Data ◽  
Spallation Neutron Source ◽  
Pump Probe ◽  
New Era ◽  
Oak Ridge ◽  
Battery Degradation ◽  
Event Based

The Spallation Neutron Source at Oak Ridge National Laboratory, USA, ushered in a new era of neutron scattering experiments through the use of event-based data. Tagging each neutron event allows pump–probe experiments, measurements with a parameter asynchronous to the source, measurements with continuously varying parameters and novel ways of testing instrument components. This contribution will focus on a few examples. A pulsed magnet has been used to study diffraction under extreme fields. Continuous ramping of temperature is becoming standard on the POWGEN diffractometer. Battery degradation and phase transformations under heat and stress are often studied on the VULCAN diffractometer. Supercooled Al2O3 was studied on NOMAD. A study of a metallic glass through its glass transition was performed on the ARCS spectrometer, and the effect of source variation on chopper stability was studied for the SEQUOIA spectrometer. Besides a summary of these examples, an overview is provided of the hardware and software advances to enable these and many other event-based measurements.

Nanodiamond Foils for H- Stripping to Support the Spallation Neutron Source (SNS) and Related Applications

2014 ◽  
Vol 1634 ◽  
Author(s):  
RD Vispute ◽  
Henry K. Ermer ◽  
Phillip Sinsky ◽  
Andrew Seiser ◽  
Robert W. Shaw ◽  
...  
Keyword(s):  
Neutron Source ◽  
Thermal Stresses ◽  
Ion Beam ◽  
National Laboratory ◽  
Chemical Vapor ◽  
Particle Accelerator ◽  
Spallation Neutron Source ◽  
Free Standing ◽  
Oak Ridge ◽  
Process Gas

ABSTRACTThin diamond foils are needed in many particle accelerator experiments regarding nuclear and atomic physics, as well as in some interdisciplinary research. Particularly, nanodiamond texture is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness; therefore, it is a potential material for energetic ion beam stripper foils. At the ORNL Spallation Neutron Source (SNS), the installed set of foils must be able to survive a nominal five-month operation period, without the need for unscheduled costly shutdowns and repairs. Thus, a single nanodiamond foil about the size of a postage stamp is critical to the entire operation of SNS and similar sources in U.S. laboratories and around the world. We are investigating nanocrystalline, polycrystalline and their admixture films fabricated using a hot filament chemical vapor deposition (HFCVD) system for H- stripping to support the SNS at Oak Ridge National Laboratory. Here we discuss optimization of process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, substrate to filament distance, filament temperature, carburization conditions, and filament geometry to achieve high purity diamond foils on patterned silicon substrates with manageable intrinsic and thermal stresses so that they can be released as free standing foils without curling. An in situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of the diamond thin film materials. The optimization process has yielded free standing foils with no pinholes. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging of the foils. The integrated LRI and HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control over film thickness. The results are discussed in the light of development of nanodiamond foils that will be able to withstand a few MW proton beam and hopefully will be able to be used after possible future upgrades to the SNS to greater than a 3MW beam.

scholarly journals Neutronics analyses for the conceptual design of the SNS Second Target Station

2020 ◽  
Vol 22 (2-3) ◽  
pp. 265-273
Author(s):  
Igor Remec ◽  
Franz X. Gallmeier
Keyword(s):  
Proton Beam ◽  
Conceptual Design ◽  
Neutron Source ◽  
Cross Sections ◽  
Energy Deposition ◽  
National Laboratory ◽  
Spallation Neutron Source ◽  
Target Station ◽  
Oak Ridge ◽  
Residual Heat

The Spallation Neutron Source, in operation at the Oak Ridge National Laboratory since 2006, was designed to allow the addition of a second target station and an upgrade of the accelerator proton power. Both upgrades are now underway. This paper describes the evolution of the design of the target of the second target station with the emphasis on the effects of the proton beam footprint on the energy deposition in the target, stresses induced by the pulsed operation, and the importance of the residual heat. The moderator configurations and their optimization are discussed. With the utilization of pure parahydrogen moderators, small neutron beam cross-sections, and the specific optimization, neutron beams of the second target station will achieve exceptionally high peak brightness and time-averaged brightness.

First data acquired on the extendedQ-range small-angle neutron scattering (EQ-SANS) diffractometer at the Spallation Neutron Source

2011 ◽  
Vol 44 (5) ◽  
pp. 1120-1122 ◽  
Author(s):  
Dazhi Liu ◽  
Kunlun Hong ◽  
Carrie Y. Gao ◽  
Yuri Melnichenko ◽  
Ken Littrell ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Neutron Source ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
National Laboratory ◽  
Model Fitting ◽  
Scattering Data ◽  
Radius Of Gyration ◽  
Spallation Neutron Source ◽  
Oak Ridge

Initial experimental results are reported from the extendedQ-range small-angle neutron scattering (EQ-SANS) diffractometer at the Spallation Neutron Source at Oak Ridge National Laboratory (ORNL). A generation-8 polyamidoamine dendrimer was measured and the conformation parameters (radius of gyration, thickness of the soft shelletc.) extracted by model fitting to the scattering data. The results are compared with data collected at the general-purpose small-angle neutron scattering (GP-SANS) beamline at the High-Flux Isotopic Reactor at ORNL and show that EQ-SANS is ready for scientific studies for the small-angle neutron scattering community.

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