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Journal articles on the topic 'Neutrons Polarization'

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Published: 10 December 2022
Last updated: 29 January 2023

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1

WEN, H., L. S. KISSLINGER, WALTER GREINER, and G. MAO. "NEUTRON SPIN POLARIZATION IN STRONG MAGNETIC FIELDS." International Journal of Modern Physics E 14, no. 08 (November 2005): 1197–204. http://dx.doi.org/10.1142/s021830130500379x.

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The effects of strong magnetic fields on the inner crust of neutron stars are investigated after taking into account the anomalous magnetic moments of nucleons. The energy spectra and wave functions for protons and neutrons in a uniform magnetic field are provided. The particle spin polarizations and the yields of protons and neutrons are calculated in a free Fermi gas model. Obvious spin polarizations occur when B≥1014 G for protons and B≥1017 G for neutrons, respectively. It is shown that the neutron spin polarization depends solely on the magnetic field strength.
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2

Kakurai, K., M. Steiner, and R. Pynn. "MAGNETIC EXCITATIONS AND POLARIZATION ANALYSIS METHOD." International Journal of Modern Physics B 07, no. 16n17 (July 30, 1993): 3095–111. http://dx.doi.org/10.1142/s0217979293003176.

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With the recent advances of efficient polarizing and flipping devices and with the increase of the absolute flux at modern neutron sources, polarized neutron inelastic scattering experiments using cold and thermal neutrons have become more commonplace. In this review paper we present experiments recently performed where this technique has been applied to obtain more detailed informations on magnetic excitations thus contributing to a deeper understanding of the spin dynamics in magnetic materials.
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3

Didelez, J. P., and C. Deutsch. "Persistence of the Polarization in a Fusion Process." Laser and Particle Beams 29, no. 2 (March 22, 2011): 169–74. http://dx.doi.org/10.1017/s0263034611000139.

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AbstractWe propose an experiment to test the persistence of the polarization in a fusion process, using a terawatt laser hitting a polarized high density (HD) target. The polarized protons and deuterons heated in the plasma induced by the laser have a significant probability to fuse producing a3He and a γ-ray or a neutron in the final state. The angular distribution of the radiated γ-rays and the change in the corresponding total cross-section are related to the polarization persistence, but the resulting signal turns out to be weak. By comparison, the neutrons are produced hadronically with a larger cross-section and it is much easier to detect them. A significant reduction of the cross-section by parallel polarization of the deuterons as well as a structured angular distribution of the emitted neutrons is reliably predicted by the theory. Therefore, it is expected that the corresponding signal on the neutron counting rate could be seen experimentally. Magnetic fields, relaxation times and possibilities of local investigations are discussed.
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4

Berikov, D., G. Ahmadov, Yu Kopatch, and V. Novitsky. "Magnetic system for controlling the spin of polarized neutrons." Journal of Instrumentation 17, no. 08 (August 1, 2022): P08030. http://dx.doi.org/10.1088/1748-0221/17/08/p08030.

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Abstract A spin control magnetic system was developed and assembled at the JINR Laboratory of Neutron Physics (Dubna, Russia) and was tested with a beam of polarized neutrons at the POLI instrument of the FRM II reactor in Garching (Germany). This paper presents the principle of operation and a method for compensating the influence of external magnetic fields on polarization using this device. The system consists of three precession coils in a magnetic screen. The first coil allows, by changing the current in it, to ensure the rotation of the neutron spin by an arbitrary angle relative to the magnetic field inside the coil. The remaining two coils are designed to compensate for the effect of scattered magnetic fields on the beam polarization, and to preserve the polarization vector direction.
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5

Frandsen, Benjamin A., Raju Baral, Barry Winn, and V. Ovidiu Garlea. "Magnetic pair distribution function data using polarized neutrons and ad hoc corrections." Journal of Applied Physics 132, no. 22 (December 14, 2022): 223909. http://dx.doi.org/10.1063/5.0130400.

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We report the first example of magnetic pair distribution function (mPDF) data obtained through the use of neutron polarization analysis. Using the antiferromagnetic semiconductor MnTe as a test case, we present high-quality mPDF data collected on the HYSPEC instrument at the Spallation Neutron Source using longitudinal polarization analysis to isolate the magnetic scattering cross section. Clean mPDF patterns are obtained for MnTe in both the magnetically ordered state and the correlated paramagnet state, where only short-range magnetic order is present. We also demonstrate significant improvement in the quality of high-resolution mPDF data through the application of ad hoc corrections that require only minimal human input, minimizing potential sources of error in the data processing procedure. We briefly discuss the current limitations and future outlook of mPDF analysis using polarized neutrons. Overall, this work provides a useful benchmark for mPDF analysis using polarized neutrons and provides an encouraging picture of the potential for routine collection of high-quality mPDF data.
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6

Gezerlis, Alexandros. "Polarization in low-density neutrons." Journal of Physics: Conference Series 426 (March 27, 2013): 012011. http://dx.doi.org/10.1088/1742-6596/426/1/012011.

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7

Kushoro, Matteo Hakeem, Marica Rebai, Marco Tardocchi, Carmen Altana, Carlo Cazzaniga, Eliana De Marchi, Francesco La Via, et al. "Detector Response to D-D Neutrons and Stability Measurements with 4H Silicon Carbide Detectors." Materials 14, no. 3 (January 26, 2021): 568. http://dx.doi.org/10.3390/ma14030568.

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The use of wide-band-gap solid-state neutron detectors is expanding in environments where a compact size and high radiation hardness are needed, such as spallation neutron sources and next-generation fusion machines. Silicon carbide is a very promising material for use as a neutron detector in these fields because of its high resistance to radiation, fast response time, stability and good energy resolution. In this paper, measurements were performed with neutrons from the ISIS spallation source with two different silicon carbide detectors together with stability measurements performed in a laboratory under alpha-particle irradiation for one week. Some consideration to the impact of the casing of the detector on the detector’s counting rate is given. In addition, the detector response to Deuterium-Deuterium (D-D) fusion neutrons is described by comparing neutron measurements at the Frascati Neutron Generator with a GEANT4 simulation. The good stability measurements and the assessment of the detector response function indicate that such a detector can be used as both a neutron counter and spectrometer for 2–4 MeV neutrons. Furthermore, the absence of polarization effects during neutron and alpha irradiation makes silicon carbide an interesting alternative to diamond detectors for fast neutron detection.
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8

Knop, W., M. Hirai, H. J. Schink, H. B. Stuhrmann, R. Wagner, J. Zhao, O. Schärpf, et al. "A new polarized target for neutron scattering studies on biomolecules: first results from apoferritin and the deuterated 50S subunit of ribosomes." Journal of Applied Crystallography 25, no. 2 (April 1, 1992): 155–65. http://dx.doi.org/10.1107/s0021889891011093.

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A new polarized target for neutron scattering has been designed by CERN and tested successfully using the reactor FRG-1 at the GKSS Research Centre. The nuclear spins are aligned with respect to the external field – parallel or antiparallel – by dynamic nuclear polarization (DNP). To avoid absorption of neutrons by 3He, the frozen solutions of biomolecules are immersed in liquid 4He which in turn is thermally coupled to the cooling mixture of 3He/4He of the dilution refrigerator. Compared with earlier experiments where the sample had been cooled directly by 3He, the rate of detectable neutrons increased by a factor of 30. Another factor of 30 is due to the installation of the cold source and the beryllium reflector in FRG-1. Polarized neutron scattering from apoferritin in deuterated solvent shows that the proton spin polarization is homogeneous in apoferritin molecules. After saturation of proton nuclear magnetic resonance (NMR), polarized neutron scattering is dominated by deuteron spin contrast. With the deuterated large subunit of E. coli ribosomes, three different basic scattering functions are derived from spin-contrast variation, reflecting the known scattering-length-density distribution of the architecture of rRNA and ribosomal proteins. The planned in situ structure determination of a mRNA fragment is discussed in the light of the present results.
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9

Harmon, J. F., D. P. Wells, and A. W. Hunt. "Neutrons and Photons in Nondestructive Detection." Reviews of Accelerator Science and Technology 04, no. 01 (January 2011): 83–101. http://dx.doi.org/10.1142/s1793626811000495.

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Active, nondestructive interrogation with neutrons and photons has seen a renaissance in recent years, owing to a broad spectrum of important applications in security, nuclear nonproliferation, contraband detection and materials analysis. Active methods are of high interest for such applications because they provide at least an order of magnitude greater sensitivity than passive methods. Accelerator-based neutron and photon active methods exploit two important factors to attain greater sensitivity: these are (i) the control of interrogating beam properties such as directionality, energy, intensity, polarization and the temporal distribution of radiation; (ii) well-founded, low energy nuclear physics that yields distinct "signatures" for elemental and isotopic content. This review addresses accelerator-based neutron and photon nondestructive testing methods and issues when applied to modern and emerging wide-ranging challenges in nondestructive detection.
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10

Ghosal, Debdeep. "Measurement of π0π+/− photoproduction off the deuteron and dbutanol targets." EPJ Web of Conferences 199 (2019): 02010. http://dx.doi.org/10.1051/epjconf/201919902010.

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Recent experiments using the Crystal Ball/TAPS setup at the MAMI accelerator in Mainz, Germany continue to study the properties and the excitation spectrum of the nucleon with meson photoproduction. Electromagnetic excitations of the proton and neutron are essential for understanding their isospin decomposition. The electromagnetic coupling of photons to protons is different than that of neutrons in certain states. Cross-section data alone is not sufficient for separating resonances, whereas polarization observables play a crucial role being essential in disentangling the contributing resonant and non-resonant amplitudes. Preliminary results of the polarization observable E of double π production off an unpolarized (LD2) and polarized (dButanol) target are shown with comparison to predictions of recent analyses.
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11

Ghosal, Debdeep. "Measurement of π0π+/- photoproduction off the deuteron and dbutanol targets." EPJ Web of Conferences 241 (2020): 01006. http://dx.doi.org/10.1051/epjconf/202024101006.

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Recent experiments using the Crystal Ball/TAPS setup at the MAMI accelerator in Mainz, Germany continue to study the properties and the excitation spectrum of the nucleon with meson photoproduction. Elec tromagnetic excitations of the proton and neutron are essential for understanding their isospin decomposition. The electromagnetic coupling of photons to protons is different than that of neutrons in certain states. Cross section data alone is not sufficient for separating resonances, whereas polarization observables play a crucial role being essential in disentangling the contributing resonant and non-resonant amplitudes. Preliminary results of the polarization observable E of double π production measured with a polarized solid deuterated Butanol target are shown with comparison to predictions of recent analyses.
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12

Ashkar, Rana, P. Stonaha, A. L. Washington, V. R. Shah, M. R. Fitzsimmons, B. Maranville, C. F. Majkrzak, W. T. Lee, W. L. Schaich, and Roger Pynn. "Dynamical theory calculations of spin-echo resolved grazing-incidence scattering from a diffraction grating." Journal of Applied Crystallography 43, no. 3 (April 30, 2010): 455–65. http://dx.doi.org/10.1107/s0021889810010642.

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Neutrons scattered or reflected from a diffraction grating are subject to a periodic potential analogous to the potential experienced by electrons within a crystal. Hence, the wavefunction of the neutrons can be expanded in terms of Bloch waves and a dynamical theory can be applied to interpret the scattering phenomenon. In this paper, a dynamical theory is used to calculate the results of neutron spin-echo resolved grazing-incidence scattering (SERGIS) from a silicon diffraction grating with a rectangular profile. The calculations are compared with SERGIS measurements made on the same grating at two neutron sources: a pulsed source and a continuous wave source. In both cases, the spin-echo polarization, studied as a function of the spin-echo length, peaks at integer multiples of the grating period but there are some differences between the two sets of data. The dynamical theory explains the differences and gives a good account of both sets of results.
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13

Vignaud, Guillaume, and Alain Gibaud. "REFLEX: a program for the analysis of specular X-ray and neutron reflectivity data." Journal of Applied Crystallography 52, no. 1 (February 1, 2019): 201–13. http://dx.doi.org/10.1107/s1600576718018186.

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The use of X-ray and neutron reflectivity has been generalized worldwide for scientists who want to determine specific physical properties (such as electron-density profile, scattering-length density, roughness and thickness) of films less than 200 nm thick deposited on a substrate. This paper describes a freeware program named REFLEX, which is a standalone program dedicated to the simulation and analysis of X-ray and neutron reflectivity from multilayers. This program was first written two decades ago and has been constantly improved since, but never published until now. The latest version of REFLEX covers generalized types of calculation of reflectivity curves including both neutron and X-ray reflectivity. In the case of X-rays, the program can deal with both s and p polarization, which is quite important in the soft X-ray region where the two polarizations can yield different results. Neutron reflectivity is calculated within the framework of non-spin-polarized neutrons. REFLEX has also been designed to include any type of fluid (such as supercritical CO2) on top of the analysed film and includes corrections of the footprint effect for analysis on an absolute scale.
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14

Ковалев, А. В. "Интерференция нейтронных волн при малоугловом рассеянии на ферромагнитных сплавах." Физика твердого тела 60, no. 10 (2018): 1924. http://dx.doi.org/10.21883/ftt.2018.10.46519.026.

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AbstractThe detection conditions and features of direct and scattered neutron wave interference are studied on magnetized Co_67Fe_31V_2 alloy slabs. The angular intensity distributions of neutrons passed through a sample are measured for the opposite polarization directions of the initial neutron beam. The sought-for effect that is induced by the magnetic scattering on crystal structure irregularities in specimens manifest itself by different areas of peaks “without neutron spin flip.” The ratio of these areas depends on the thermal treatment mode, sample thickness and strength of the magnetic field applied to the sample. The peaks “with neutron spin flip” are due to the mechanism of neutron wave passage through magnetononcollinear boundaries. The methods for experimental data acquisition and processing are reported as well.
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15

Thoma, Henrik, Wolfgang Luberstetter, Jürgen Peters, and Vladimir Hutanu. "Polarized neutron diffraction using a novel high-Tcsuperconducting magnet on the single-crystal diffractometer POLI at MLZ." Journal of Applied Crystallography 51, no. 1 (February 1, 2018): 17–26. http://dx.doi.org/10.1107/s160057671800078x.

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The polarized single-crystal diffractometer POLI is the first neutron scattering instrument routinely using3He spin filters both to produce and to analyse neutron polarization. The instrument, with a non-magnetic goniometer, was designed to perform two types of polarized neutron diffraction experiment: spherical neutron polarimetry, also known as full three-dimensional polarization analysis in zero magnetic field, and classical polarized neutron diffraction, also called the flipping-ratio (FR) method, in high applied magnetic fields. Reported here is the implementation of the FR setup for short-wavelength neutrons on POLI using a new high-Tcsuperconducting magnet with a maximal field of 2.2 T. The complete setup consists of a3He polarizer, a nutator, a Mezei-type flipper, guide fields and dedicated pole pieces, together with the magnet. Each component, as well as the whole setup, was numerically simulated, optimized, built and finally successfully tested under real experimental conditions on POLI. The measured polarized neutron spin transport efficiency is about 99% at different wavelengths,e.g.as short as 0.7 Å, and up to the maximal available field of the magnet. No further depolarization of the3He cells due to stray fields of the magnet occurs. The additional use of the available3He analyser allows uniaxial polarization analysis experiments in fields up to 1.2 T. The results of the first experiment on the field-dependent distribution of the trigonal antiferromagnetic domains in haematite (α-Fe2O3) are presented and compared with the literature data.
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16

Golub, R., and R. Gähler. "Neutrons with 〈σz〉 > 100 and “polarization amplification”." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 284, no. 1 (November 1989): 188–89. http://dx.doi.org/10.1016/0168-9002(89)90278-7.

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17

Garusov, E. A., E. P. Lifshits, and Yu V. Petrov. "Polarization of fast neutrons in VVR-M reactor." Soviet Atomic Energy 61, no. 5 (November 1986): 881–84. http://dx.doi.org/10.1007/bf01122265.

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18

Zimmer, Oliver, Thierry Bigault, Skyler Degenkolb, Christoph Herb, Thomas Neulinger, Nicola Rizzi, Valentina Santoro, Alan Takibayev, Richard Wagner, and Luca Zanini. "In-beam superfluid-helium ultracold neutron source for the ESS." Journal of Neutron Research 24, no. 2 (January 5, 2023): 95–110. http://dx.doi.org/10.3233/jnr-220045.

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This paper discusses design principles and possible performances of an “in-beam” ultracold neutron (UCN) source for the European Spallation Source (ESS). The key components of the proposed neutron delivery system are nested-mirror optics (NMO), which image the bright neutron emission surface of the large liquid-deuterium moderator, studied within the HighNESS project, onto a remotely located superfluid-helium converter. Bandpass supermirrors, with optional polarization capability, enable the selective transport of those neutrons that are most effective for UCN production, exploiting the single-phonon conversion process that is possible for neutrons having wavelengths within a narrow range centered on 8.9 A ˚. NMO are capable of extracting and refocusing neutrons with small transport losses under the large solid angle available at the ESS Large Beam Port (LBP), allowing the converter to be placed far away from the high-radiation area in the ESS shielding bunker, where the source stays accessible for trouble-shooting while facilitating a low-background environment for nearby UCN experiments. Various configurations of the beam and converter are possible, including a large-volume converter – with or without a magnetic reflector – for a large total UCN production rate, or a beam focused onto a small converter for highest possible UCN density. The source performances estimated by first simulations of a baseline version presented in this paper, including a saturated UCN density on the order of 10 5 cm − 3 , motivate further study and the development of NMO beyond the first prototypes that have been recently investigated experimentally.
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19

Okudaira, Takuya, Yuki Ueda, Kosuke Hiroi, Ryuhei Motokawa, Yasuhiro Inamura, Shin-ichi Takata, Takayuki Oku, et al. "Polarization analysis for small-angle neutron scattering with a 3He spin filter at a pulsed neutron source." Journal of Applied Crystallography 54, no. 2 (March 25, 2021): 548–56. http://dx.doi.org/10.1107/s1600576721001643.

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Neutron polarization analysis (NPA) for small-angle neutron scattering (SANS) experiments using a pulsed neutron source was successfully achieved by applying a 3He spin filter as a spin analyzer for the neutrons scattered from the sample. The cell of the 3He spin filter gives a weak small-angle scattering intensity (background) and covers a sufficient solid angle for performing SANS experiments. The relaxation time of the 3He polarization is sufficient for continuous use for approximately 2 days, thus reaching the typical duration required for a complete set of SANS experiments. Although accurate evaluation of the incoherent neutron scattering, which is predominantly attributable to the extremely large incoherent scattering cross section of hydrogen atoms in samples, is difficult using calculations based on the sample elemental composition, the developed NPA approach with consideration of the influence of multiple neutron scattering enabled reliable decomposition of the SANS intensity distribution into the coherent and incoherent scattering components. To date, NPA has not been well established as a standard technique for SANS experiments at pulsed neutron sources such as the Japan Proton Accelerator Research Complex (J-PARC) and the US Spallation Neutron Source. It is anticipated that this work will contribute significantly to the accurate determination of the coherent neutron scattering component for scatterers in various types of organic sample systems in SANS experiments at J-PARC, particularly for systems involving competition between the coherent and incoherent scattering intensity.
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20

Quan, Yifan, Jakob Steiner, Victor Ukleev, Joachim Kohlbrecher, Alexei Vorobiev, and Patrick Hautle. "Impact of the neutron-depolarization effect on polarized neutron scattering in ferromagnets." IUCrJ 8, no. 3 (April 13, 2021): 455–61. http://dx.doi.org/10.1107/s2052252521003249.

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It has been known for decades that a ferromagnetic sample can depolarize a transmitted neutron beam. This effect was used and developed into the neutron-depolarization technique to investigate the magnetic structure of ferromagnetic materials. Since the polarization evolves continuously as the neutrons move through the sample, the initial spin states on scattering will be different at different depths within the sample. This leads to a contamination of the measured spin-dependent neutron-scattering intensities by the other spin-dependent cross sections. The effect has rarely been considered in polarized neutron-scattering experiments even though it has a crucial impact on the observable signal. A model is proposed to describe the depolarization of a neutron beam traversing a ferromagnetic sample, provide the procedure for data correction and give guidelines to choose the optimum sample thickness. It is experimentally verified for a small-angle neutron-scattering geometry with samples of the nanocristalline soft-magnet Vitroperm (Fe73Si16B7Nb3Cu1). The model is general enough to be adapted to other types of neutron-diffraction experiments and sample geometries.
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21

Tanaka, Ichiro, Naoya Komatsuzaki, Wen-Xue Yue, Toshiyuki Chatake, Katsuhiro Kusaka, Nobuo Niimura, Daisuke Miura, et al. "Cryoprotectant-free high-pressure cooling and dynamic nuclear polarization for more sensitive detection of hydrogen in neutron protein crystallography." Acta Crystallographica Section D Structural Biology 74, no. 8 (July 17, 2018): 787–91. http://dx.doi.org/10.1107/s2059798318005028.

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To improve the sensitivity of hydrogen detection using neutrons, a proton-polarization technique together with a high-pressure cooling method is necessary. The highest pressure (200 MPa) used in the experiment described here enabled relatively large protein crystals to be cooled without any cryoprotectants while retaining the protein structure, and it was confirmed that high-pressure-cooled crystals diffracted to nearly the same resolution as flash-cooled small crystals soaked with cryoprotectants. Dynamic nuclear polarization was used as a proton-polarization technique for protein crystals, and ∼300 mg polycrystalline protein doped with TEMPOL gave a maximum proton polarization of 22.3% at a temperature of 0.5 K in a 2.5 T magnetic field.
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22

Sales, Morten, Jeroen Plomp, Klaus Habicht, and Markus Strobl. "Investigating time-of-flight spin-echo modulation for small-angle neutron scattering through experiments and simulation." Journal of Applied Crystallography 48, no. 1 (January 30, 2015): 92–96. http://dx.doi.org/10.1107/s1600576714025916.

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A spin-echo-modulated small-angle neutron scattering (SEMSANS) instrument in a time-of-flight (TOF) mode will be able to excel at pulsed neutron sources such as the European Spallation Source (ESS), currently under construction. This work compares experimental data from a TOF SEMSANS setup, where a spatial beam modulation of a white beam is obtained using triangular field coils, with Monte Carlo ray-tracing simulations. The experiments and simulations in accordance demonstrate that a good contrast can be achieved when using a constant field in the triangular coils. In the reported setup only neutrons with certain wavelengths rotate by a Larmor precession angle that spatially modulates their polarization to coincide with the period of a grating installed at the detector position. This is shown by measuring with a broad wavelength range while scanning the echo condition.
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23

Pynn, Roger, M. R. Fitzsimmons, W. T. Lee, V. R. Shah, A. L. Washington, P. Stonaha, and Ken Littrell. "Spin echo scattering angle measurement at a pulsed neutron source." Journal of Applied Crystallography 41, no. 5 (August 16, 2008): 897–905. http://dx.doi.org/10.1107/s0021889808020402.

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Two experiments were performed to adapt spin echo scattering angle measurement (SESAME) to pulsed neutron sources. SESAME is an interferometric method that provides enhanced resolution of neutron scattering angles without the loss of neutron intensity that results when collimation is used to improve angular resolution. The method uses the neutron equivalent of optical wave plates to produce a phase difference between the two neutron spin components of a polarized neutron beam. Because the wave plate is inclined to the neutron beam, this phase difference depends sensitively on the trajectory of the neutron. In the absence of a sample, a second wave plate, which is parallel to the first, undoes the phase difference introduced by the first wave plate, producing a polarization identical to that of the incident neutron beam. When a scattering sample is placed between the two neutron wave plates, the cancellation of the phase difference between the neutron spin states is not perfect and the resulting neutron-beam polarization is a measure of the distribution of scattering angles. In the first experiment, thin (30 and 60 µm-thick) magnetized Permalloy films were used as neutron wave plates. In a second experiment, current-carrying solenoids with triangular cross sections were used as birefringent prisms for neutrons. The arrangement of these prisms was such that they mimicked the effect of the neutron wave plates in the first experiment. In both experiments, correlation lengths in the scattering sample of about 1000 Å were probed using very simple and inexpensive equipment. These experiments brought to light a number of advantages and disadvantages of implementing SESAME at pulsed neutron sources and provided insights into the relative merits of SESAME and traditional small-angle neutron scattering.
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24

Berezhnoy, Yu A., and V. A. Slipko. "Polarization Phenomena in Inclusive Nucleon Transfer Reactions." International Journal of Modern Physics E 07, no. 06 (December 1998): 723–46. http://dx.doi.org/10.1142/s0218301398000415.

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The theory of the polarization phenomena in the inclusive one- and two-nucleon transfer reactions (d,n) and (3 H ,n) at intermediate energies is developed on the basis of the S-matrix approach. Since the parameters of the S-matrix are found from fitting the experimental data for the elastic scattering of protons by the nuclei, the calculated polarization observables of the neutrons released in reactions 40 Ca (d,n), 208 Pb (d,n), 40 Ca (3 H ,n) and 208 Pb (3 H ,n) in the wide energy region do not have any free parameters.
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25

Sarsour, M., J. Amadio, E. Anderson, L. Barrón-Palos, B. Crawford, C. Crawford, D. Esposito, et al. "Neutron spin rotation measurements." EPJ Web of Conferences 219 (2019): 06002. http://dx.doi.org/10.1051/epjconf/201921906002.

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The neutron spin rotation (NSR) collaboration used parity-violating spin rotation of transversely polarized neutrons transmitted through a 0.5 m liquid helium target to constrain weak coupling constants between nucleons. While consistent with theoretical expectation, the upper limit set by this measurement on the rotation angle is limited by statistical uncertainties. The NSR collaboration is preparing a new measurement to improve this statistically-limited result by about an order of magnitude. In addition to using the new high-flux NG-C beam at the NIST Center for Neutron Research, the apparatus was upgraded to take advantage of the larger-area and more divergent NG-C beam. Significant improvements are also being made to the cryogenic design. Details of these improvements and readiness of the upgraded apparatus are presented. We also comment on how recent theoretical work combining effective field theory techniques with the 1/Nc expansion of QCD along with previous NN weak measurements can be used to make a prediction for dϕ/dz in 4He. An experiment using the same apparatus with a room-temperature target was carried out at LANSCE to place limits on parity-conserving rotations from possible fifth-force interactions to complement previous studies. We sought this interaction using a slow neutron polarimeter that passed transversely polarized slow neutrons by unpolarized slabs of material arranged so that this interaction would tilt the plane of polarization and develop a component along the neutron momentum. The results of this measurement and its impact on the neutron-matter coupling gA2 from such an interaction are presented. The NSR collaboration is also preparing a new measurement that uses an upgraded version of the room-temperature target to be run on the NG-C beamline; and it is expected to constrain gA2 by at least two additional orders of magnitude for λc between 1 cm and 1 μm.
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26

Vlasova, M. O., N. D. Galanina, V. S. Demidov, A. A. Nedosekin, A. Ya Ostapchuk, V. A. Sadykov, N. A. Khaldeeva, et al. "Polarization of leading Λ hyperons produced by neutrons on target nuclei." Journal of Experimental and Theoretical Physics Letters 64, no. 4 (August 1996): 258–62. http://dx.doi.org/10.1134/1.567195.

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27

Fleming, Nina C., and Ayman I. Hawari. "Structure-Dependent Doppler Broadening Using a Generalized Thermal Scattering Law." Journal of Nuclear Engineering 2, no. 2 (April 8, 2021): 124–31. http://dx.doi.org/10.3390/jne2020013.

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The thermal scattering law (TSL), i.e., S(α,β), represents the momentum and energy exchange phase space for a material. The incoherent and coherent components of the TSL correlate an atom’s trajectory with itself and/or with other atoms in the lattice structure. This structural information is especially important for low energies where the wavelength of neutrons is on the order of the lattice interatomic spacing. Both thermal neutron scattering as well as low energy resonance broadening involve processes where incoming neutron responses are lattice dependent. Traditionally, Doppler broadening for absorption resonances approximates these interactions by assuming a Maxwell–Boltzmann distribution for the neutron velocity. For high energies and high temperatures, this approximation is reasonable. However, for low temperatures or low energies, the lattice structure binding effects will influence the velocity distribution. Using the TSL to determine the Doppler broadening directly introduces the material structure into the calculation to most accurately capture the momentum and energy space. Typically, the TSL is derived assuming cubic lattice symmetry. This approximation collapses the directional lattice information, including the polarization vectors and associated energies, into an energy-dependent function called the density of states. The cubic approximation, while valid for highly symmetric and uniformly bonded materials, is insufficient to capture the true structure. In this work, generalized formulation for the exact, lattice-dependent TSL is implemented within the Full Law Analysis Scattering System Hub (FLASSH) using polarization vectors and associated energies as fundamental input. These capabilities are utilized to perform the generalized structure Doppler broadening analysis for UO2.
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28

Wood, Kathleen, Jitendra P. Mata, Christopher J. Garvey, Chun-Ming Wu, William A. Hamilton, Peter Abbeywick, Daniel Bartlett, et al. "QUOKKA, the pinhole small-angle neutron scattering instrument at the OPAL Research Reactor, Australia: design, performance, operation and scientific highlights." Journal of Applied Crystallography 51, no. 2 (March 20, 2018): 294–314. http://dx.doi.org/10.1107/s1600576718002534.

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QUOKKA is a 40 m pinhole small-angle neutron scattering instrument in routine user operation at the OPAL research reactor at the Australian Nuclear Science and Technology Organisation. Operating with a neutron velocity selector enabling variable wavelength, QUOKKA has an adjustable collimation system providing source–sample distances of up to 20 m. Following the large-area sample position, a two-dimensional 1 m2position-sensitive detector measures neutrons scattered from the sample over a secondary flight path of up to 20 m. Also offering incident beam polarization and analysis capability as well as lens focusing optics, QUOKKA has been designed as a general purpose SANS instrument to conduct research across a broad range of scientific disciplines, from structural biology to magnetism. As it has recently generated its first 100 publications through serving the needs of the domestic and international user communities, it is timely to detail a description of its as-built design, performance and operation as well as its scientific highlights. Scientific examples presented here reflect the Australian context, as do the industrial applications, many combined with innovative and unique sample environments.
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29

GOULD, C. R., D. G. HAASE, N. R. ROBERSON, H. POSTMA, and J. D. BOWMAN. "PARITY AND TIME REVERSAL VIOLATION IN RESONANCE NEUTRON TOTAL CROSS SECTIONS WITH POLARIZED TARGETS." International Journal of Modern Physics A 05, no. 11 (June 10, 1990): 2181–94. http://dx.doi.org/10.1142/s0217751x90001008.

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The formalism for evaluating parity and time reversal violating terms in total cross sections of polarized targets and low energy resonance neutrons is reviewed. A complete set of symmetry violating terms (P-odd, T-even; P-odd, T-odd; and P-even, T-odd) is obtained by analyzing the dependence of the cross section on the statistical tensors describing the beam and target. Results are tabulated in numerical and closed analytic form, using the j-spin representation. P-odd, T-even experiments are classified, with emphasis on experiments with an unpolarized beam and a polarized target where the effect of induced polarization is found to be small. Different combinations of partial neutron widths are shown to enter when P-odd, T-odd effects are compared to P-odd, T-even effects. The results for P-even, T-odd experiments for single level and two level mixing are summarized.
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30

Carlson, B. V., and M. S. Hussein. "Spin polarization and rotation of polarized epithermal neutrons scattered off heavy nuclei." Physical Review C 56, no. 1 (July 1, 1997): 292–95. http://dx.doi.org/10.1103/physrevc.56.292.

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31

Abdukadyrova, I. Kh. "Influence of neutrons on the rotation of the polarization plane of quartz." Soviet Atomic Energy 59, no. 5 (November 1985): 950–51. http://dx.doi.org/10.1007/bf01133099.

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32

Bazhenov, A. N., L. A. Grigor'eva, V. V. Ivanov, E. A. Kolomensky, V. M. Lobashev, V. A. Nazarenko, A. N. Pirozhkov, and Yu V. Sobolev. "Circular polarization of γ-quanta in np→dγ reactions with polarized neutrons." Physics Letters B 289, no. 1-2 (September 1992): 17–21. http://dx.doi.org/10.1016/0370-2693(92)91355-d.

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33

Burichenko, A. P., and I. B. Khriplovich. "Circular polarization of γ-quanta in the reaction np → dγ with polarized neutrons." Nuclear Physics A 515, no. 1 (August 1990): 139–46. http://dx.doi.org/10.1016/0375-9474(90)90327-i.

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34

MYO, TAKAYUKI, KIYOSHI KATŌ, HIROSHI TOKI, and KIYOMI IKEDA. "EXTENDED THREE-BODY ANALYSIS OF 11LI WITH TENSOR AND PAIRING CORRELATIONS." Modern Physics Letters A 21, no. 31n33 (October 30, 2006): 2491–98. http://dx.doi.org/10.1142/s0217732306022158.

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We investigate the tensor and pairing correlations in 11 Li based on the 9 Li +n+n model. For 9 Li , we perform the configuration mixing with the shell model type wave function to introduce the core polarization caused by the tensor and pairing correlations. For 11 Li , we perform the coupled 9 Li +n+n calculation, in which the couplings between the correlations in 9 Li and the motion of the last two neutrons emerge Pauli-blocking for the p2 configuration of 11 Li and increases the s2 component to develop the halo structure.
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35

Aulenbacher, Kurt, Eugene Chudakov, David Gaskell, Joseph Grames, and Kent D. Paschke. "Precision electron beam polarimetry for next generation nuclear physics experiments." International Journal of Modern Physics E 27, no. 07 (July 2018): 1830004. http://dx.doi.org/10.1142/s0218301318300047.

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Polarized electron beams have played an important role in scattering experiments at moderate to high beam energies. Historically, these experiments have been primarily targeted at studying hadronic structure — from the quark contribution to the spin structure of protons and neutrons, to nucleon elastic form factors, as well as contributions to these elastic form factors from (strange) sea quarks. Other experiments have aimed to place constraints on new physics beyond the Standard Model. For most experiments, knowledge of the magnitude of the electron beam polarization has not been a limiting systematic uncertainty, with only moderately precise beam polarimetry requirements. However, a new generation of experiments will require extremely precise measurements of the beam polarization, significantly better than 1%. This paper will review standard electron beam polarimetry techniques and possible future technologies, with an emphasis on the ever-improving precision that is being driven by the requirements of electron scattering experiments.
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36

Hilmer, F., A. Schirmer, H. Ackermann, P. Heitjans, and H. J. Stöckmann. "β-Radiation Detected NMR in Solid and Liquid Neon." Zeitschrift für Naturforschung A 49, no. 1-2 (February 1, 1994): 27–30. http://dx.doi.org/10.1515/zna-1994-1-207.

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Abstract Spin-polarized β-active 23Ne (T1/2 = 37.2s) nuclei were created by capture of polarized cold neutrons in solid and liquid neon. The angular asymmetry of the β-radiation was used to monitor the nuclear polarization. From nuclear magnetic resonance curves the value for the dipole moment |μ(23Ne)| = 1.079(1) n.m. (uncorrected) was obtained which is more precise than the literature value. Comparing the measured spin-lattice relaxation rates with those of stable 21Ne the nuclear quadru­pole moment of 23N e was determined. It agrees with a shell model calculation. The feasibility of 23Ne-β-NMR for investigations in condensed rare gases in demonstrated.
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37

Abele, H., A. Boucher, P. Geltenbort, M. Klein, U. Schmidt, and C. Stellmach. "Radio frequency-induced polarization of ultra-cold neutrons or how to pump a two-level system." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 440, no. 3 (February 2000): 760–63. http://dx.doi.org/10.1016/s0168-9002(99)01078-5.

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38

Manie, N. S. "Quadrupole moment of 14B exotic nucleus." Iraqi Journal of Physics (IJP) 12, no. 23 (February 18, 2019): 44–50. http://dx.doi.org/10.30723/ijp.v12i23.337.

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The quadrupole moment of 14B exotic nucleus has been calculated using configuration mixing shell model with limiting number of orbital's in the model space. The core- polarization effects, are included through a microscopic theory which considers a particle-hole excitations from the core and the model space orbits into the higher orbits with 6ħω excitations using M3Y interaction. The simple harmonic oscillator potential is used to generate the single particle wave functions. Large basis no-core shell model with (0+2)ћω truncation is used for 14B nucleus. The effective charges for the protons and neutrons were calculated successfully and the theoretical quadrupole moment was compared with the experimental data, which was found to be in a good agreement.
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39

Garlea, V. Ovidiu, Stuart Calder, Thomas Huegle, Jiao Y. Y. Lin, Fahima Islam, Alexandru Stoica, Van B. Graves, Benjamin Frandsen, and Stephen D. Wilson. "VERDI: VERsatile DIffractometer with wide-angle polarization analysis for magnetic structure studies in powders and single crystals." Review of Scientific Instruments 93, no. 6 (June 1, 2022): 065103. http://dx.doi.org/10.1063/5.0090919.

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The VERsatile DIffractometer will set a new standard for a world-class magnetic diffractometer with versatility for both powder and single crystal samples and capability for wide-angle polarization analysis. The instrument will utilize a large single-frame bandwidth and will offer high-resolution at low momentum transfers and excellent signal-to-noise ratio. A horizontal elliptical mirror concept with interchangeable guide pieces will provide high flexibility in beam divergence to allow for a high-resolution powder mode, a high-intensity single crystal mode, and a polarized beam option. A major science focus will be quantum materials that exhibit emergent properties arising from collective effects in condensed matter. The unique use of polarized neutrons to isolate the magnetic signature will provide optimal experimental input to state-of-the-art modeling approaches to access detailed insight into local magnetic ordering.
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40

Wada, N., T. Shinohara, H. Sato, H. Hasemi, T. Kamiyama, and Y. Kiyanagi. "Evaluation of Magnetic Field Vector by Polarization Analysis Using Pulsed Neutrons at HUNS for Magnetic Field Imaging." Physics Procedia 69 (2015): 427–35. http://dx.doi.org/10.1016/j.phpro.2015.07.060.

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41

Arnold, J., B. van den Brandt, M. Daum, M. Finger, M. Finger, J. Franz, N. Goujon-Naef, et al. "Kinetic energy spectrum and polarization of neutrons from the reaction 12C(p,n)X at 590 MeV." European Physical Journal A 2, no. 4 (August 1998): 411–15. http://dx.doi.org/10.1007/s100500050138.

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42

Khudayer, Firas Y. "Inelastic longitudinal electron scattering C42 form factors in42Ti nucleus." Iraqi Journal of Physics (IJP) 14, no. 30 (January 13, 2019): 1–8. http://dx.doi.org/10.30723/ijp.v14i30.189.

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Inelastic longitudinal electron scattering form factors for secondexcited state C42 in 42Ti nucleus have been calculated using shellmodel theory. Fp shell model space with configuration (1f7/2 2p3/21f5/2 2p1/2) has been adopted in order to distribute the valenceparticles (protons and neutrons) outside an inert core 40Ca. Modernmodel space effective interactions like FPD6 and GXPF1 have beenused to generate model space vectors and harmonic oscillator wavefunction as a single particle wave function. Discarder space (coreorbits + higher orbits) has been included in (core polarization effect)as a first order correction in microscopic theory to measure theinterested multipole form factors via the model space.Gogny and Michigan sum of three-range Yukawapotential (M3Y-p2) have been utilized as a residual interaction tocouple the (particle-hole) pair across the model space active particlesand the excitation energy of the pair is (2ħω) and four options for theused effective and residual interactions were determined for thetransitions from (+0) to (+01,2,3), (+21,2,3) and (+41,2,3).
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43

Anker, A., P. Baldi, S. W. Barwick, J. Beise, D. Z. Besson, S. Bouma, M. Cataldo, et al. "Measuring the polarization reconstruction resolution of the ARIANNA neutrino detector with cosmic rays." Journal of Cosmology and Astroparticle Physics 2022, no. 04 (April 1, 2022): 022. http://dx.doi.org/10.1088/1475-7516/2022/04/022.

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Abstract The ARIANNA detector is designed to detect neutrinos with energies above 1017 eV. Due to the similarities in generated radio signals, cosmic rays are often used as test beams for neutrino detectors. Some ARIANNA detector stations are equipped with antennas capable of detecting air showers. Since the radio emission properties of air showers are well understood, and the polarization of the radio signal can be predicted from the arrival direction, cosmic rays can be used as a proxy to assess the reconstruction capabilities of the ARIANNA neutrino detector. We report on dedicated efforts of reconstructing the polarization of cosmic-ray radio pulses. After correcting for difference in hardware, the two stations used in this study showed similar performance in terms of event rate and agreed with simulation. Subselecting high quality cosmic rays, the polarizations of these cosmic rays were reconstructed with a resolution of 2.5° (68% containment), which agrees with the expected value obtained from simulation. A large fraction of this resolution originates from uncertainties in the predicted polarization because of the contribution of the subdominant Askaryan effect in addition to the dominant geomagnetic emission. Subselecting events with a zenith angle greater than 70° removes most influence of the Askaryan emission, and, with limited statistics, we found the polarization uncertainty is reduced to 1.3° (68% containment).
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44

Noda, Yohei, Tomoki Maeda, Takayuki Oku, Satoshi Koizumi, Tomomi Masui, and Hiroyuki Kishimoto. "First Experiment of Spin Contrast Variation Small-Angle Neutron Scattering on the iMATERIA Instrument at J-PARC." Quantum Beam Science 4, no. 4 (September 25, 2020): 33. http://dx.doi.org/10.3390/qubs4040033.

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Recently, we have developed a novel dynamic nuclear polarization (DNP) apparatus with a magnetic field of 7 T and a sample temperature of 1 K. High proton spin polarizations from −84% to 76%, for TEMPO doped polystyrene samples, have been demonstrated. This DNP apparatus satisfies the simultaneous requirement for quick and easy sample exchange and high DNP performance. On the iMATERIA (BL20) instrument at J-PARC, the first beam experiment using this DNP apparatus has been performed. For this experiment, the beamline was equipped with a supermirror polarizer. The stray magnetic field due to the superconducting magnet for DNP was also evaluated. The stray magnetic field plays an important role for in maintaining the neutron polarization during the transportation from the polarizer to the sample. The small-angle neutron scattering (SANS) profiles of silica-filled rubber under dynamically polarized conditions are presented. By applying our new analytical approach for SANS coherent scattering intensity, neutron polarization (PN) as a function of neutron wavelength was determined. Consequently, for the neutron wavelength, range from 4 Å to 10 Å, |PN| was sufficient for DNP-SANS studies.
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45

Sato, Taku, Yusuke Nambu, Tao Hong, Masaaki Matsuda, Huibo Cao, Masataka Kinoshita, Shinichiro Seki, Shintaro Ishiwata, and Yoshinori Tokura. "Magnetic structure of the chiral triangular magnet MnSb2O6." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C387. http://dx.doi.org/10.1107/s2053273314096120.

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Incommensurate helical (or cycloidal) magnetic structure may have left- and right-wound states (helicity), which are in principle equally populated in a magnet with inversion symmetry. In addition, for a Heisenberg triangular antiferromagnet, clockwise and counter-clockwise rotations of the 120 degree spin structure provide another intriguing degree of freedom. Hence, a triangular magnet that has incommensurate helical ordering along the stacking direction will show intriguing interplay of the helicity (of the helical structure) and chirality (in the triangular plane). Such phenomenon is, however, rarely studied in the past since only one example, the Ba3NbFe3Si2O14 langathite, has been known to date [1]. In this work, we study MnSb2O6, which consists of distorted triangular lattice stacking along the c-axis [2,3]. MnSb2O6 belongs to the space group P321, and hence lacks inversion symmetry. Due to this fact, unique selection of the helicity and chirality may be expected. However, the earlier studies were carried out using unpolarized neutron diffraction with mostly the powder sample, and thus helicity and chirality selection cannot be concluded. Here, we have performed single-crystal diffraction experiment using polarized neutrons in addition to the unpolarized ones, and have succeeded in determination of the magnetic structure of MnSb2O6. The resulting magnetic structure is nearly cycloidal with the magnetic modulation vector q = (0, 0, 0.182) (see figure below). The spin rotation plane is, however, inclined from the ac-plane toward the b-axis for approximately 30 degrees. Polarization analysis indicates that both the helicity of the (nearly-) cycloidal structure and chirality of the in-plane 120 degree structure are uniquely selected. The 30 degree inclination from the ac-plane is a key finding of this work, allowing new kind of multiferroicity in this material.
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46

Ghosh, Sutapa, Soma Mandal, and Somenath Chakrabarty. "Impossibility of Spin Polarized States for Neutron Star/Proto-Neutron Star Matter in β-Equilibrium Condition." Modern Physics Letters A 18, no. 19 (June 21, 2003): 1297–302. http://dx.doi.org/10.1142/s0217732303008867.

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It is shown explicitly that a ferromagnetic transition of neutron star (NS)/proto-neutron star (PNS) matter in the β-equilibrium condition with σ-ω-ρ exchange type of mean field approximation can actually occur if and only if the neutrinos remain trapped within the system, and perhaps it is also necessary for the neutrinos/anti-neutrinos to carry some finite nonzero mass. It is further shown that the electrons also play a significant role in this transition process. It is therefore, very much unlikely that such a transition of spin polarization can really take place in old neutron stars of very low temperature, whereas, the possibility of spontaneous ferromagnetic transition cannot be ruled out in a newly born PNS.
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47

Mdekil, Abdullah S. "The effect of short range correlation on the inelastic C2 and C4 form factors of 18O nucleus." Iraqi Journal of Physics (IJP) 14, no. 31 (January 13, 2019): 37–50. http://dx.doi.org/10.30723/ijp.v14i31.170.

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The effect of short range correlations on the inelastic Coulomb form factors for excited +2 states (1.982, 3.919, 5.250 and 8.210MeV) and +4 states (3.553, 7.114, 8.960 and 10.310 MeV) in O18 is analyzed. This effect (which depends on the correlation parameterβ) is inserted into the ground state charge density distribution through the Jastrow type correlation function. The single particle harmonic oscillator wave function is used with an oscillator size parameter .b The parameters β and b are adjusted for each excited state separately so as to reproduce the experimental root mean square charge radius of .18O The nucleusO18 is considered as an inert core of C12 with two protons and four neutrons distributed over 212521211sdp−− active orbits. The total transition charge density comes from both the model space and core polarization transition charge densities. The realistic effective interaction of Reehal–Wildenthal (REWIL) is used for this model space. It is found that the introduction of the effect of short range correlations is necessary for obtaining a remarkable improvement for the calculated inelastic Coulomb form factors and considered as an essential for explanation the data amazingly throughout the whole range of considered momentum transfer.
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48

Abdullaeva, Umsalimat, Vadim Shakhov, Alexander Studenikin, and Alexander Tsvirov. "Dirac and Majorana neutrino oscillations in magnetized moving and polarized matter." Journal of Physics: Conference Series 2156, no. 1 (December 1, 2021): 012229. http://dx.doi.org/10.1088/1742-6596/2156/1/012229.

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Abstract In the present paper we develop the quantum theory of neutrino spin and spin-flavour oscillations in moving magnetized matter with a special focus on the effects of matter polarization. We derive an effective neutrino evolution Hamiltonian and corresponding expressions for the neutrino oscillation probabilities. Both the case of Dirac and Majorana neutrinos are considered. From the comparison of the neutrino spin oscillation probabilities in the transversally moving matter for the Dirac and Majorana neutrinos it follows that the oscillation patterns is different for theses two cases. In particular, the conditions for the resonances in these two cases are realized at different densities of matter.
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49

Jullien, David, Alexandre Petoukhov, Mechthild Enderle, Nicolas Thiery, Pascal Mouveau, Ursula Bengaard Hansen, Philippe Chevalier, and Pierre Courtois. "New design of a magnetic device for wide-angle XYZ polarization analysis PASTIS-3, from the concept to first tests with thermal neutrons." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 1010 (September 2021): 165558. http://dx.doi.org/10.1016/j.nima.2021.165558.

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50

Paret, Daryel Manreza, A. Perez Martinez, Alejandro Ayala, G. Piccinelli, and A. Sanchez. "Neutron stars velocities and magnetic fields." EPJ Web of Conferences 172 (2018): 07002. http://dx.doi.org/10.1051/epjconf/201817207002.

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We study a model that explain neutron stars velocities due to the anisotropic emission of neutrinos. Strong magnetic fields present in neutron stars are the source of the anisotropy in the system. To compute the velocity of the neutron star we model its core as composed by strange quark matter and analice the properties of a magnetized quark gas at finite temperature and density. Specifically we have obtained the electron polarization and the specific heat of magnetized fermions as a functions of the temperature, chemical potential and magnetic field which allow us to study the velocity of the neutron star as a function of these parameters.
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