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Sample records for 3he neutron spin

  1. 3He Spin Filter for Neutrons

    PubMed Central

    Batz, M.; Baeßler, S.; Heil, W.; Otten, E. W.; Rudersdorf, D.; Schmiedeskamp, J.; Sobolev, Y.; Wolf, M.

    2005-01-01

    The strongly spin-dependent absorption of neutrons in nuclear spin-polarized 3He opens up the possibility of polarizing neutrons from reactors and spallation sources over the full kinematical range of cold, thermal and hot neutrons. This paper gives a report on the neutron spin filter (NSF) development program at Mainz. The polarization technique is based on direct optical pumping of metastable 3He atoms combined with a polarization preserving mechanical compression of the gas up to a pressure of several bar, necessary to run a NSF. The concept of a remote type of operation using detachable NSF cells is presented which requires long nuclear spin relaxation times of order 100 hours. A short survey of their use under experimental conditions, e.g. large solid-angle polarization analysis, is given. In neutron particle physics NSFs are used in precision measurements to test fundamental symmetry concepts. PMID:27308139

  2. Spin Duality on the Neutron (^3He)

    SciTech Connect

    Solvignon, Patricia

    2007-02-01

    Thomas Jefferson National Accelerator Facility experiment E01-012 measured the 3He spin structure functions and virtual photon asymmetries in the resonance region in the momentum transfer range 1.0 < Q2 < 4.0 (GeV/c)2. Our date, when compared with existing deep inelastic scattering data, can be used to test quark-hadron duality in g1 and A1 for 3He and the neutron. Preliminary results for A{sub 1}{sup {sup 3}He} are presented, as well as some details about the experiment.

  3. Polarized 3He Spin Filters for Slow Neutron Physics

    PubMed Central

    Gentile, T. R.; Chen, W. C.; Jones, G. L.; Babcock, E.; Walker, T. G.

    2005-01-01

    Polarized 3He spin filters are needed for a variety of experiments with slow neutrons. Their demonstrated utility for highly accurate determination of neutron polarization are critical to the next generation of betadecay correlation coefficient measurements. In addition, they are broadband devices that can polarize large area and high divergence neutron beams with little gamma-ray background, and allow for an additional spin-flip for systematic tests. These attributes are relevant to all neutron sources, but are particularly well-matched to time of flight analysis at spallation sources. There are several issues in the practical use of 3He spin filters for slow neutron physics. Besides the essential goal of maximizing the 3He polarization, we also seek to decrease the constraints on cell lifetimes and magnetic field homogeneity. In addition, cells with highly uniform gas thickness are required to produce the spatially uniform neutron polarization needed for beta-decay correlation coefficient experiments. We are currently employing spin-exchange (SE) and metastability-exchange (ME) optical pumping to polarize 3He, but will focus on SE. We will discuss the recent demonstration of 75 % 3He polarization, temperature-dependent relaxation mechanism of unknown origin, cell development, spectrally narrowed lasers, and hybrid spin-exchange optical pumping. PMID:27308140

  4. Quark-Hadron Duality in Neutron (3He) Spin Structure

    SciTech Connect

    Solvignon, Patricia; Liyanage, Nilanga; Chen, Jian-Ping; Choi, Seonho; Aniol, Konrad; Averett, Todd; Boeglin, Werner; Camsonne, Alexandre; Cates, Gordon; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chudakov, Eugene; Craver, Brandon; Cusanno, Francesco; Deur, Alexandre; Dutta, Dipangkar; Ent, Rolf; Feuerbach, Robert; Frullani, Salvatore; Gao, Haiyan; Garibaldi, Franco; Gilman, Ronald; Glashausser, Charles; Gorbenko, Viktor; Hansen, Jens-Ole; Higinbotham, Douglas; Ibrahim, Hassan; Jiang, Xiaodong; Jones, Mark; Kelleher, Aidan; Kelly, J.; Keppel, Cynthia; Kim, Wooyoung; Korsch, Wolfgang; Kramer, Kevin; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Ma, Bin; Margaziotis, Demetrius; Markowitz, Pete; McCormick, Kathy; Meziani, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Monaghan, Peter; Munoz-Camacho, Carlos; Paschke, Kent; Reitz, Bodo; Saha, Arunava; Sheyor, Ran; Singh, Jaideep; Slifer, Karl; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Tobias, William; Urciuoli, Guido; Wang, Kebin; Wijesooriya, Krishni; Wojtsekhowski, Bogdan; Woo, Seungtae; Yang, Jae-Choon; Zheng, Xiaochao; Zhu, Lingyan

    2008-10-01

    We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_1 of the neutron and $^3$He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c)^2. Global duality is observed for the spin-structure function g_1 down to at least Q^2 = 1.8 (GeV/c)^2 in both targets. We have also formed the photon-nucleon asymmetry A_1 in the resonance region for 3He and found no strong Q^2-dependence above 2.2 (GeV/c)^2.

  5. Optimised adiabatic fast passage spin flipping for 3He neutron spin filters

    NASA Astrophysics Data System (ADS)

    McKetterick, T. J.; Boag, S.; Stewart, J. R.; Frost, C. D.; Skoda, M. W. A.; Parnell, S. R.; Babcock, E.

    2011-06-01

    We describe here a method of performing adiabatic fast passage (AFP) spin flipping of polarized 3He used as a neutron spin filter (NSF) to polarize neutron beams. By reversing the spin states of the 3He nuclei the polarization of a neutron beam can be efficiently reversed allowing for the transmission of a neutron beam polarized in either spin state. Using an amplitude modulated frequency sweep lasting 500 ms we can spin flip a polarized 3He neutron spin filter with only 1.8×10-5 loss in 3He polarization. The small magnetic fields (10-15 G) used to house neutron spin filters mean the 3He resonant frequencies are low enough to be generated using a computer with a digital I/O card. The versatility of this systems allows AFP to be performed on any beamline or in any laboratory using 3He neutron spin filters and polarization losses can be minimised by adjusting sweep parameters.

  6. Spin echo small angle neutron scattering using a continuously pumped {sup 3}He neutron polarisation analyser

    SciTech Connect

    Parnell, S. R.; Li, K.; Yan, H.; Stonaha, P.; Li, F.; Wang, T.; Baxter, D. V.; Snow, W. M.; Washington, A. L.; Walsh, A.; Chen, W. C.; Parnell, A. J.; Fairclough, J. P. A.; Pynn, R.

    2015-02-15

    We present a new instrument for spin echo small angle neutron scattering (SESANS) developed at the Low Energy Neutron Source at Indiana University. A description of the various instrument components is given along with the performance of these components. At the heart of the instrument are a series of resistive coils to encode the neutron trajectory into the neutron polarisation. These are shown to work well over a broad range of neutron wavelengths. Neutron polarisation analysis is accomplished using a continuously operating neutron spin filter polarised by Rb spin-exchange optical pumping of {sup 3}He. We describe the performance of the analyser along with a study of the {sup 3}He polarisation stability and its implications for SESANS measurements. Scattering from silica Stöber particles is investigated and agrees with samples run on similar instruments.

  7. Highlights of JLab Neutron (3He) Spin Program

    SciTech Connect

    Jian-ping Chen

    2009-07-01

    Nucleon spin structure has been an active, exciting and intriguing subject of interest for the last three decades. Recent precision spin-structure data from Jefferson Lab have significantly advanced our knowledge of nucleon structure at low Q2. In particular, it has improved our understanding of spin sum rules and higher-twist effects. First, results of neutron spin sum rules and polarizabilities in the low to intermediate Q2 region are presented. Comparison with theoretical calculations, in particular with Chiral Perturbation Theory (ChPT) calculations, are discussed. Surprising disagreements of ChPT calculations with experimental results on the generalized spin polarizability, deltaLTn, were found. Results of precision measurements of the g2 structure function to study higher-twist effects are presented. The data indicate a significant higher-twist (twist-3 or higher) effect. The second moment of the spin structure functions and the twist-3 matrix element d2 results were extracted. The high Q2 result was compared with a Lattice QCD calculation. Finally, other neutron spin structure results, such as the resonance data for quark-hadron duality study and a precision measurement of the neutron spin asymmetry in the valence quark (high-x) region are briefly discussed.

  8. Recent advances in polarized 3 He based neutron spin filter development

    NASA Astrophysics Data System (ADS)

    Chen, Wangchun; Gentile, Thomas; Erwin, Ross; Watson, Shannon; Krycka, Kathryn; Ye, Qiang; NCNR NIST Team; University of Maryland Team

    2015-04-01

    Polarized 3 He neutron spin filters (NSFs) are based on the strong spin-dependence of the neutron absorption cross section by 3 He. NSFs can polarize large area, widely divergent, and broadband neutron beams effectively and allow for combining a neutron polarizer and a spin flipper into a single polarizing device. The last capability utilizes 3 He spin inversion based on the adiabatic fast passage (AFP) nuclear magnetic resonance technique. Polarized 3 He NSFs are significantly expanding the polarized neutron measurement capabilities at the NIST Center for Neutron Research (NCNR). Here we present an overview of 3 He NSF applications to small-angle neutron scattering, thermal triple axis spectrometry, and wide-angle polarization analysis. We discuss a recent upgrade of our spin-exchange optical pumping (SEOP) systems that utilize chirped volume holographic gratings for spectral narrowing. The new capability allows us to polarize rubidium/potassium hybrid SEOP cells over a liter in volume within a day, with 3 He polarizations up to 88%, Finally we discuss how we can achieve nearly lossless 3 He polarization inversion with AFP.

  9. A compact SEOP 3He neutron spin filter with AFP NMR

    NASA Astrophysics Data System (ADS)

    Ino, Takashi; Arimoto, Yasushi; Shimizu, Hirohiko M.; Sakaguchi, Yoshifumi; Sakai, Kenji; Kira, Hiroshi; Shinohara, Takenao; Oku, Takayuki; Suzuki, Jun-ichi; Kakurai, Kazuhisa; Chang, Lieh-Jeng

    2012-02-01

    We developed AFP NMR in an aluminum container for polarized noble gas nuclei. The radio frequency magnetic field inside the aluminum container was designed from computer simulations. The polarization loss by the AFP spin flip of 3He was measured to be as low as 3.8×10-4. With this technique, a compact in-situ polarizing 3He neutron spin filter with AFP NMR is demonstrated.

  10. A New Method for Precision Cold Neutron Polarimetry Using a 3He Spin Filter

    PubMed Central

    Wietfeldt, F. E.; Gentile, T. R.

    2005-01-01

    We present a new method for precision measurement of the capture flux polarization of a polychromatic (white), continuous cold neutron beam, polarized by a 3He spin filter. This method allows an in situ measurement and does not require knowledge of the neutron beam wavelength distribution. We show that a polarimetry precision of 0.1 % is possible.

  11. The Neutron and 3He Spin Structure Functions at Low Q^2

    SciTech Connect

    Vincent Sulkosky

    2009-08-01

    Experiment E97-110 was performed at the Thomas Jefferson National Accelerator Facility in Hall A to provide a precise measurement of the moments of the neutron and $^{3}$He spin structure functions. A longitudinally-polarized electron beam was scattered from a longitudinally or transversely polarized $^{3}$He target. The extended Gerasimov-Drell-Hearn integral and other moments of the neutron and $^{3}$He spin structure functions were extracted at very low momentum transfers (0.02 $< Q^{2} <$ 0.3 [GeV$/c$]$^{2}$). These data allow us to make a benchmark check of Chiral Perturbation Theory calculations in a region where they are expected to be valid. In these proceedings, the experimental details are discussed and preliminary results on the moments of the spin structure functions are presented.

  12. SEOP polarized 3He Neutron Spin Filters for the JCNS user program

    NASA Astrophysics Data System (ADS)

    Babcock, Earl; Salhi, Zahir; Theisselmann, Tobias; Starostin, Denis; Schmeissner, Johann; Feoktystov, Artem; Mattauch, Stefan; Pistel, Patrick; Radulescu, Aurel; Ioffe, Alexander

    2016-04-01

    Over the past several years the JCNS has been developing in-house applications for neutron polarization analysis (PA). These methods include PA for separation of incoherent from coherent scattering in soft matter studies (SANS), and online polarization for analysis for neutron reflectometry, SANS, GISANS and eventually spectroscopy. This paper will present an overview of the user activities at the JCNS at the MLZ and gives an overview of the polarization 3He methods and devices used. Additionally we will summarise current projects which will further support the user activities using polarised 3He spin filters.

  13. Conceptual design of a polarized 3He neutron spin filter for polarized neutron spectrometer POLANO at J-PARC

    NASA Astrophysics Data System (ADS)

    Ino, T.; Ohoyama, K.; Yokoo, T.; Itoh, S.; Ohkawara, M.; Kira, H.; Hayashida, H.; Sakai, K.; Hiroi, K.; Oku, T.; Kakurai, K.; Chang, L. J.

    2016-04-01

    A 3He neutron spin filter (NSF) has been designed for a new polarized neutron chopper spectrometer called the Polarization Analysis Neutron Spectrometer with Correlation Method (POLANO) at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. It is designed to fit in a limited space on the spectrometer as an initial neutron beam polarizer and is polarized in situ by spin exchange optical pumping. This will be the first generation 3He NSF on POLANO, and a polarized neutron beam up to 100 meV with a diameter of 50 mm will be available for research on magnetism, hydrogen materials, and strongly correlated electron systems.

  14. ^3He Spin Pump

    NASA Astrophysics Data System (ADS)

    Yamaguchi, A.; Ishimoto, H.; Kojima, H.

    2009-03-01

    The superfluid component of ^3He A1 phase is spin-polarized. The process of forcing the superfluid component through a spin filtering structure, in a manner of mechano-magnetic effect, can be used to increase the spin polarization beyond the equilibrium under a given applied magnetic field. We have constructed a test cell in which a glass capillary array acts as the spin (and entropy) filter and an electrostatically actuated diaphragm forces the superfluid flow through it. Preliminary results show that a maximum relative increase of polarization by 50 % could be achieved. The maximum increase in polarization appears to be limited by the critical superfluid flow through the channels in the glass capillary array. The dependence of the observed effects on temperature, pressure and magnetic field will be presented.

  15. Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

    NASA Astrophysics Data System (ADS)

    Hayashida, H.; Oku, T.; Kira, H.; Sakai, K.; Hiroi, K.; Ino, T.; Shinohara, T.; Imagawa, T.; Ohkawara, M.; Ohoyama, K.; Kakurai, K.; Takeda, M.; Yamazaki, D.; Oikawa, K.; Harada, M.; Miyata, N.; Akutsu, K.; Mizusawa, M.; Parker, J. D.; Matsumoto, Y.; Zhang, S.; Suzuki, J.; Soyama, K.; Aizawa, K.; Arai, M.

    2016-04-01

    We have been developing a 3He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3He polarization reached 70% and was stable over one week. A demonstration of the 3He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively.

  16. End-compensated magnetostatic cavity for polarized 3He neutron spin filters.

    PubMed

    McIver, J W; Erwin, R; Chen, W C; Gentile, T R

    2009-06-01

    We have expanded upon the "Magic Box" concept, a coil driven magnetic parallel plate capacitor constructed out of mu-metal, by introducing compensation sections at the ends of the box that are tuned to limit end-effects similar to those of short solenoids. This ability has reduced the length of the magic box design without sacrificing any loss in field homogeneity, making the device far more applicable to the often space limited neutron beam line. The appeal of the design beyond affording longer polarized 3He lifetimes is that it provides a vertical guide field, which facilitates neutron spin transport for typical polarized beam experiments. We have constructed two end-compensated magic boxes of dimensions 28.4 x 40 x 15 cm3 (length x width x height) with measured, normalized volume-averaged transverse field gradients ranging from 3.3 x 10(-4) to 6.3 x 10(-4) cm(-1) for cell sizes ranging from 8.1 x 6.0 to 12.0 x 7.9 cm2 (diameter x length), respectively. PMID:19566213

  17. Study of neutron spin structure functions at low Q{sup 2} with polarized {sup 3}He

    SciTech Connect

    Seonho Choi

    2000-12-12

    The recently completed experiment E94-010 at Jefferson Lab studies the neutron spin structure functions at low momentum transfer (Q{sup 2}) values. Using a polarized {sup 3} He target and polarized electron beam, we have measured the asymmetries and cross sections for {sup 3}He(e,e') from the elastic to the deep inelastic region. The covered Q{sup 2} ranges from 0.03 to 1.1 GeV{sup 2}. From the data, the Q{sup 2} evolution of the spin structure functions for {sup 3}He and neutron, and of the Gerasimov-Drell-Hearn (GDH) sum rule has been studied, and the preliminary results are presented.

  18. Spin exchange optical pumping based polarized {sup 3}He filling station for the Hybrid Spectrometer at the Spallation Neutron Source

    SciTech Connect

    Jiang, C. Y.; Tong, X.; Brown, D. R.; Culbertson, H.; Kadron, B.; Robertson, J. L.; Graves-Brook, M. K.; Hagen, M. E.; Lee, W. T.; Winn, B.

    2013-06-15

    The Hybrid Spectrometer (HYSPEC) is a new direct geometry spectrometer at the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is equipped with polarization analysis capability with 60 Degree-Sign horizontal and 15 Degree-Sign vertical detector coverages. In order to provide wide angle polarization analysis for this instrument, we have designed and built a novel polarized {sup 3}He filling station based on the spin exchange optical pumping method. It is designed to supply polarized {sup 3}He gas to HYSPEC as a neutron polarization analyzer. In addition, the station can optimize the {sup 3}He pressure with respect to the scattered neutron energies. The depolarized {sup 3}He gas in the analyzer can be transferred back to the station to be repolarized. We have constructed the prototype filling station. Preliminary tests have been carried out demonstrating the feasibility of the filling station. Here, we report on the design, construction, and the preliminary results of the prototype filling station.

  19. Neutron spin filters (NSF) obtained by metastability-exchange optical pumping (MEOP) and mechanical compressing of 3He gas

    NASA Astrophysics Data System (ADS)

    Hutanu, V.; Habicht, Klaus; Rupp, A.

    2004-10-01

    NSF using gaseous polarized 3He became a popular tool for many polarized neutron scattering applications due to the number of advantages that this technique presents, but also due to significant increasing of technical performancies demonstrated in that field in the last years. The realization of flexible and reliable devices for neutron beam polarization is a focal point in the instrumental development program at the Hahn-Meitner Institute Berlin (HMI). The technique applied in our case to obtain nuclear-spin-polarized 3He is metastability-exchange optical pumping (MEOP) using a cw Nd:LNA laser with 5.8 W output power and 2.5 GHz bandwidth. The general aspects regarding optical pumping in optical polarizing cells are described. The construction of the optical pumping volume is presented, the last results regarding optical pumping cells (OPC) and filter cells preparation are discussed. The status and perspectives of the project are presented.

  20. The Spin Structure of 3He and the Neutron at Low Q^2: A Measurement of the Generalized GDH Integrand

    SciTech Connect

    Sulkosky, Vincent

    2007-08-01

    Since the 1980's, the study of nucleon (proton or neutron) spin structure has been an active field both experimentally and theoretically. One of the primary goals of this work is to test our understanding of Quantum Chromodynamics (QCD), the fundamental theory of the strong interaction. In the high energy region of asymptotically free quarks, QCD has been verified. However, verifiable predictions in the low energy region are harder to obtain due to the complex interactions between the nucleon's constituents: quarks and gluons. In the non-pertubative regime, low-energy effective field theories such as chiral perturbation theory provide predictions for the spin structure functions in the form of sum rules. Spin-dependent sum rules such as the Gerasimov-Drell-Hearn (GDH) sum rule are important tools available to study nucleon spin structure. Originally derived for real photon absorption, the Gerasimov-Drell-Hearn (GDH) sum rule was first extended for virtual photon absorption in 1989. The extension of the sum rule provides a unique relation, valid at any momentum transfer ($Q^{2}$), that can be used to study the nucleon spin structure and make comparisons between theoretical predictions and experimental data. Experiment E97-110 was performed at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) to examine the spin structure of the neutron and $^{3}$He. The Jefferson Lab longitudinally-polarized electron beam with incident energies between 1.1 and 4.4 GeV was scattered from a longitudinally or transversely polarized $^{3}$He gas target in the Hall A end station. Asymmetries and polarized cross-section differences were measured in the quasielastic and resonance regions to extract the spin structure functions $g_{1}(x,Q^{2})$ and $g_{2}(x,Q^{2})$ at low momentum transfers (0.02 $< Q^{2} <$ 0.3 GeV$^{2}$). The goal of the experiment was to perform a precise measurement of the $Q^{2}$ dependence of the extended GDH integral and of the moments of the neutron

  1. Neutron Polarizers Based on Polarized 3He

    SciTech Connect

    William M. Snow

    2005-05-01

    The goal of this work, which is a collaborative effort between Indiana University, NIST, and Hamilton College, is to extend the technique of polarized neutron scattering into new domains by the development and application of polarized 3He-based neutron spin filters. After the IPNS experiment which measured Zeeman sp[litting in surface scattered neutrons using a polarized 3He cell as a polarization analyzer transporterd by car from Bloomington to Chicago, the Indiana work focused on technical developments to improve the 3He polarization of the Indiana compression system. The compression system was rebuilt with a new valve system which allows gas trapped in the dead volume of the compressors at the end of the piston stroke to be exhausted and conducted back to the optical pumping cell where it can be repolarized. We also incorporated a new intermediate storage volume made at NIST from 1720 glass which will reduce polarization losses between the compressors. Furthermore, we improved the stability of the 1083 nm laser by cooling the LMA rod. We achieved 60% 3he polarization in the optical pumping cell and 87% preservation of the polarization during compression. In parallel we built a magnetically-shielded transport solenoid for use on neutron scattering instruments such as POSY which achieves a fractional field uniformity of better than 10-3 per cm. The field was mapped using an automated 3D field mapping system for in-situ measurement of magnetic field gradients Diluted magnetic semiconductors offer many exciting opportunities for investigation of spintronic effects in solids and are certain to be one of the most active areas of condensed matter physics over then next several years. These materials can act as efficient spin injectors for devices that make use of spin-dependent transport phenomena. We just (late July 2002) finished a neutron reflectivity experiment at NIST on a GaMnAs trilayer film. This material is a ferromagnetic semiconductor which is of interest

  2. Neutron polarizers based on polarized ^3He

    NASA Astrophysics Data System (ADS)

    Gentile, T. R.; Jones, G. L.; Thompson, A. K.; Fei, X.; Keith, C. D.; Rich, D.; Snow, W. M.; Penttila, S.

    1997-10-01

    Research is underway at NIST, Indiana Univ., and LANL to develop neutron polarizers and analyzers based on polarized ^3He. Such devices, which rely on the strong spin dependence of the neutron capture cross section by polarized ^3He, have applications in weak interaction physics and materials science. In addition, the technology for polarized ^3He production is directly applicable to polarized gas MRI of lungs, and polarized targets. Our program, which includes both the spin-exchange and metastability-exchange optical pumping methods, will be reviewed. Spin-exchange has been used to analyze a polarized cold neutron beam at NIST, and also for lung imaging in collaboration with the Univ. of Pennsylvania. In the metastable method, the ^3He is polarized at low pressure, and must be substantially compressed. A piston compressor has been designed for this goal at Indiana Univ. and is under construction. At NIST we have compressed polarized gas using an apparatus that is based on a modified commercial diaphragm pump.

  3. In-situ compact 3He neutron spin polarizer based on a magneto-static cavity with built-in NMR coils

    NASA Astrophysics Data System (ADS)

    Lee, S.; Moon, M. K.; Kim, J.; Cho, S. J.; Lee, J. H.; Lee, C.-H.; Lee, S. W.; Ino, T.

    2016-04-01

    A polarized 3He neutron polarizer for in-situ neutron beam line operation was developed based on a compact magneto-static cavity with a dimension of 280×270×300 mm3 and a fiber-coupled VBG (Volume Bragg Grating) diode laser with a narrow spectral bandwidth of 25 GHz. Built-in NMR coils of the neutron spin polarizer designed for NMR signal measurements were described in detail and their performances were tested for monitoring the progress of in-situ 3He polarization.

  4. Limit on Lorentz-Invariance- and CPT-Violating Neutron Spin Interactions Using a 3He-129Xe Comagnetometer

    NASA Astrophysics Data System (ADS)

    Allmendinger, F.; Schmidt, U.; Heil, W.; Karpuk, S.; Sobolev, Yu.; Tullney, K.

    2016-02-01

    We performed a search for a Lorentz-invariance- and CPT-violating coupling of the 3He and 129Xe nuclear spins to posited background fields. Our experimental approach is to measure the free precession of nuclear spin polarized 3He and 129Xe atoms using SQUIDs as detectors. As the laboratory reference frame rotates with respect to distant stars, we look for a sidereal modulation of the Larmor frequencies of the co-located spin samples. As a result we obtain an upper limit on the equatorial component of the background field b˜⊥n < 8.4 ṡ 10‑34 GeV (68% C.L.). This experiment is currently the most precise test of spin anisotropy due to the excellent long spin-coherence time.

  5. Applications of {sup 3}He neutron detectors

    SciTech Connect

    Testov, D. A.; Briancon, Ch.; Dmitriev, S. N.; Yeremin, A. V.; Penionzhkevich, Yu. E.; Pyatkov, Yu. V.; Sokol, E. A.

    2009-01-15

    Neutron detectors with {sup 3}He-filled proportional counters are described. The use of these detectors in measuring the probability of neutron emission (in particular, multiparticle neutron emission) after the {beta} decay of neutron-rich nuclei and in studying rare events of spontaneous fission of superheavy nuclei is considered.

  6. Measurement of the Neutron (3He) Spin Structure at Low Q2 and the Extended Gerasimov-Drell-Hearn Sum Rule

    SciTech Connect

    Kominis, Ioannis

    2001-01-31

    This thesis presents the results of E-94010, an experiment at Thomas Jefferson National Accelerator Facility (TJNAF) designed to study the spin structure of the neutron at low momentum transfer, and to test the “extended” Gerasimov-Drell-Hearn (GDH) sum rule. The first experiment of its kind, it was performed in experimental Hall-A of TJNAF using a new polarized 3He facility. It has recently been shown that the GDH sum rule and the Bjorken sum rule are both special examples of a more general sum rule that applies to polarized electron scattering off nucleons. This generalized sum rule, due to Ji and Osborne, reduces to the GDH sum rule at Q2 = 0 and to the Bjorken sum rule at Q2 >> 1 GeV2. By studying the Q2 evolution of the extended GDH sum, one learns about the transition from quark-like behavior to hadronic-like behavior. We measured inclusive polarized cross sections by scattering high energy polarized electrons off the new TJNAF polarized 3He target with both longitudinal and transverse target orientations. The high density 3He target, based on optical pumping and spin exchange, was used as an effective neutron target. The target maintained a polarization of about 35% at beam currents as high as 151tA. We describe the precision 3He polarimetry leading to a systematic uncertainty of the target polarization of 4% (relative). A strained GaAs photocathode was utilized in the polarized electron gun, which provided an electron beam with a polarization of about 70%, known to 3% (relative). By using six different beam energies (between 0.86 and 5.06 GeV) and a fixed scattering angle of 15.5°, a wide kinematic coverage was achieved, with 0.02 GeV2< Q2 <1 GcV2 and 0.5 GeV< W < 2.5 GeV for the squared momentum transfer and invariant mass, respectively. From the measured cross sections we extract the 3He spin structure functions He and g1e Finally, we determine the extended GDH sum for the range 0.1 GeV2< Q2 <1 GeV2 for 3He and the neutron.

  7. Measurement of the 3He Spin Structure Functions in the Resonance Region: A Test of Quark-Hadron Duality on the Neutron

    SciTech Connect

    Solvignon, Patricia

    2006-08-31

    One of the biggest challenges in the study of the nucleon structure is the understanding of the transition from partonic degrees of freedom to hadronic degrees of freedom. In 1970, Bloom and Gilman noticed that structure function data taken at SLAC in the resonance region average to the scaling curve of deep inelastic scattering (DIS). Early theoretical interpretations suggested that these two very different regimes can be linked under the condition that the quark-gluon and quark-quark interactions are suppressed. Substantial efforts are ongoing to investigate this phenomenon both experimentally and theoretically. Quark-hadron duality has been confirmed for the unpolarized structure function F{sub 2} of the proton and the deuteron using data from the experimental Hall C at Jefferson Lab (JLab). Indications of duality have been seen for the proton polarized structure function g{sub 1} and the virtual photon asymmetry A{sub 1} at JLab Hall B and HERMES. Because of the different resonance behavior, it is expected that the onset of duality for the neutron will happen at lower momentum transfer than for the proton. Now that precise spin structure data in the DIS region are available at large x, data in the resonance region are greatly needed in order to test duality in spin-dependent structure functions. The goal of experiment E01-012 was to provide such data on the neutron ({sup 3}He) in the moderate momentum transfer (Q{sup 2}) region, 1.0 < Q{sup 2} < 4.0 (GeV/c{sup 2}), where duality is expected to hold. The experiment ran successfully in early 2003 at Jefferson Lab in Hall B. It was an inclusive measurement of longitudinally polarized electrons scattering from a longitudinally or transversely polarized {sup 3}He target. Asymmetries and cross section differences were measured in order to extract the {sup 3}He spin structure function g{sub 1} and virtual photon asymmetry A{sub 1} in the resonance region. A test of quark-hadron duality has then been performed for the

  8. High Efficiency Spin Flipper for the n3He Experiment

    NASA Astrophysics Data System (ADS)

    Hayes, Christopher; n3He Collaboration

    2015-10-01

    The n3He experiment, constructed on the Fundamental Neutron Physics Beamline (FnPB) at the Spallation Neutron Source, is designed to measure the parity violating (PV) proton asymmetry Ap in the capture reaction n +3 He -->3 H + p + 765 keV The asymmetry has an estimated value Ap ~ - 1 ×10-7 and is directly related to the weak isospin conserved couplings hρ0 and ωρ0 which are of fundamental interest in the verification of the meson exchange model of low energy NN intereactions. Data production for the n3He experiment began in February 2015 and is scheduled to continue thru December 2015 - reaching a statistical sensitivity δAp ~10-8 or better. I will discuss the spin flipper which is designed using the theory of double cosine-theta coils, and capable of flipping neutron spins with an efficiency approaching its maximum value ɛsf = 1 . I will also discuss the theory of Spin Magnetic Resonance (SMR) and how it is employed by the spin flipper to flip 60 Hz pulses of cold neutrons over a range of wavelengths.

  9. Neutron Detection Alternatives to 3He for National Security Applications

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.; Erikson, Luke E.; Kernan, Warnick J.; Lintereur, Azaree T.; Siciliano, Edward R.; Stephens, Daniel L.; Stromswold, David C.; Van Ginhoven, Renee M.; Woodring, Mitchell L.

    2010-11-21

    One of the main uses for 3He is in gas proportional counters for neutron detection. Large radiation detection systems deployed for homeland security and proliferation detection applications use such systems. Due to the large increase in use of 3He for homeland security and basic research, the supply has dwindled, and can no longer meet the demand. This has led to the search for an alternative technology to replace the use of 3He-based neutron detectors. In this paper, we review the testing of currently commercially available alternative technologies for neutron detection in large systems used in various national security applications.

  10. Neutron Multiplicity Measurements With 3He Alternative: Straw Neutron Detectors

    DOE PAGESBeta

    Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Meade, John A.; Detweiler, Ryan; Maurer, Richard J.; Mitchell, Stephen E.; Guss, Paul P.; Lacy, Jeffrey L.; Sun, Liang; Athanasiades, Athanasios

    2015-01-27

    Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as “ship effect”) and to the complicated nature of the neutron scattering in that environment. In this study, a prototype neutron detector was built using 10B as the converter in a special form factor called “straws” that would address the above problems by looking into the details of multiplicity distributions ofmore » neutrons originating from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of 3He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used 10B (in the form of enriched boron carbide: 10B4C) for neutron detection instead of 3He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and developed a data acquisition (DAQ) system to collect

  11. Neutron multiplicity ,easurements With 3He alternative: Straw neutron detectors

    DOE PAGESBeta

    Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Meade, John A.; Detweiler, Ryan; Maurer, Richard J.; Mitchell, Stephen E.; Guss, Paul P.; Lacy, Jeffrey L.; Sun, Liang; Athanasiades, Athanasios

    2015-01-27

    Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as “ship effect”) and to the complicated nature of the neutron scattering in that environment. In this study, a prototype neutron detector was built using 10B as the converter in a special form factor called “straws” that would address the above problems by looking into the details of multiplicity distributions ofmore » neutrons originating from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of 3He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used 10B (in the form of enriched boron carbide: 10B4C) for neutron detection instead of 3He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and developed a data acquisition (DAQ) system to collect

  12. Dressed spin of polarized 3He in a cell

    NASA Astrophysics Data System (ADS)

    Chu, P.-H.; Esler, A. M.; Peng, J. C.; Beck, D. H.; Chandler, D. E.; Clayton, S.; Hu, B.-Z.; Ngan, S. Y.; Sham, C. H.; So, L. H.; Williamson, S.; Yoder, J.

    2011-08-01

    We report a measurement of the modification of the effective precession frequency of polarized 3He atoms in response to a dressing field in a room-temperature cell. The 3He atoms were polarized using the metastability spin-exchange method. An oscillating dressing field was then applied perpendicular to the constant magnetic field. Modification of the 3He effective precession frequency was observed over a broad range of the amplitude and frequency of the dressing field. The observed effects are compared with calculations based on quantum optics formalism.

  13. Dressed spin of polarized {sup 3}He in a cell

    SciTech Connect

    Chu, P.-H.; Esler, A. M.; Peng, J. C.; Beck, D. H.; Chandler, D. E.; Clayton, S.; Williamson, S.; Yoder, J.; Hu, B.-Z.; Ngan, S. Y.; Sham, C. H.; So, L. H.

    2011-08-15

    We report a measurement of the modification of the effective precession frequency of polarized {sup 3}He atoms in response to a dressing field in a room-temperature cell. The {sup 3}He atoms were polarized using the metastability spin-exchange method. An oscillating dressing field was then applied perpendicular to the constant magnetic field. Modification of the {sup 3}He effective precession frequency was observed over a broad range of the amplitude and frequency of the dressing field. The observed effects are compared with calculations based on quantum optics formalism.

  14. Thermal Conductivity of Spin-Polarized Liquid {sup 3}He

    SciTech Connect

    Sawkey, D.; Puech, L.; Wolf, P.E.

    2006-06-02

    We present the first measurements of the thermal conductivity of spin-polarized normal liquid {sup 3}He. Using the rapid melting technique to produce nuclear polarizations up to 0.7, and a vibrating wire both as a heater and a thermometer, we show that, unlike the viscosity, the conductivity increases much less than predicted for s-wave scattering. We suggest that this might be due to a small probability for head-on collisions between quasiparticles.

  15. 3He Spin-Dependent Cross Sections and Sum Rules

    SciTech Connect

    Slifer, Karl; Amaryan, Moscov; Amaryan, Moskov; Auerbach, Leonard; Averett, Todd; Berthot, J.; Bertin, Pierre; Bertozzi, William; Black, Tim; Brash, Edward; Brown, D.; Burtin, Etienne; Calarco, John; Cates, Gordon; Chai, Zhengwei; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Ciofi, Claudio; Cisbani, Evaristo; De Jager, Cornelis; Deur, Alexandre; DiSalvo, R.; Dieterich, Sonja; Djawotho, Pibero; Finn, John; Fissum, Kevin; Fonvieille, Helene; Frullani, Salvatore; Gao, Haiyan; Gao, Juncai; Garibaldi, Franco; Gasparian, Ashot; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Glashausser, Charles; Glockle, W.; Golak, J.; Goldberg, Emma; Gomez, Javier; Gorbenko, Viktor; Hansen, Jens-Ole; Hersman, F.; Holmes, Richard; Huber, Garth; Hughes, Emlyn; Humensky, Thomas; Incerti, Sebastien; Iodice, Mauro; Jensen, S.; Jiang, Xiaodong; Jones, C.; Jones, G.; Jones, Mark; Jutier, Christophe; Kamada, H.; Ketikyan, Armen; Kominis, Ioannis; Korsch, Wolfgang; Kramer, Kevin; Kumar, Krishna; Kumbartzki, Gerfried; Kuss, Michael; Lakuriqi, Enkeleida; Laveissiere, Geraud; LeRose, John; Liang, Meihua; Liyanage, Nilanga; Lolos, George; Malov, Sergey; Marroncle, Jacques; McCormick, Kathy; McKeown, Robert; Meziani, Zein-Eddine; Michaels, Robert; Mitchell, Joseph; Nogga, Andreas; Pace, Emanuele; Papandreou, Zisis; Pavlin, Tina; Petratos, Gerassimos; Pripstein, David; Prout, David; Ransome, Ronald; Roblin, Yves; Rowntree, David; Rvachev, Marat; Sabatie, Franck; Saha, Arunava; Salme, Giovanni; SCOPETTA, S.; Skibinski, R.; Souder, Paul; Saito, Teijiro; Strauch, Steffen; Suleiman, Riad; Takahashi, Kazunori; Todor, Luminita; Tsubota, Hiroaki; Ueno, Hiroaki; Urciuoli, Guido; van der Meer, Rob; Vernin, Pascal; Voskanyan, Hakob; Witala, Henryk; Wojtsekhowski, Bogdan; Xiong, Feng; Xu, Wang; Yang, Jae-Choon; Zhang, Bin; Zolnierczuk, Piotr

    2008-07-01

    We present a measurement of the spin-dependent cross sections for the \\vec{^3He}(\\vec{e},e')X} reaction in the quasielastic and resonance regions at four-momentum transfer 0.1 < Q^2< 0.9 GeV^2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt--Cottingham and extended GDH sum rules for the first time. Impulse approximation and exact three-body Faddeev calculations are also compared to the data in the quasielastic region.

  16. In situ polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source.

    PubMed

    Tong, X; Jiang, C Y; Lauter, V; Ambaye, H; Brown, D; Crow, L; Gentile, T R; Goyette, R; Lee, W T; Parizzi, A; Robertson, J L

    2012-07-01

    We report on the in situ polarized (3)He neutron polarization analyzer developed for the time-of-flight Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. Using the spin exchange optical pumping method, we achieved a (3)He polarization of 76% ± 1% and maintained it for the entire three-day duration of the test experiment. Based on transmission measurements with unpolarized neutrons, we show that the average analyzing efficiency of the (3)He system is 98% for the neutron wavelength band of 2-5 Å. Using a highly polarized incident neutron beam produced by a supermirror bender polarizer, we obtained a flipping ratio of >100 with a transmission of 25% for polarized neutrons, averaged over the wavelength band of 2-5 Å. After the cell was depolarized for transmission measurements, it was reproducibly polarized and this performance was maintained for three weeks. A high quality polarization analysis experiment was performed on a reference sample of Fe/Cr multilayer with strong spin-flip off-specular scattering. Using a combination of the position sensitive detector, time-of-flight method, and the excellent parameters of the (3)He cell, the polarization analysis of the two-dimensional maps of reflected, refracted, and off-specular scattered intensity above and below the horizon were obtained, simultaneously. PMID:22852718

  17. Precision neutron interferometric measurement of the n- 3He coherent neutron scattering length

    NASA Astrophysics Data System (ADS)

    Huffman, P. R.; Jacobson, D. L.; Schoen, K.; Arif, M.; Black, T. C.; Snow, W. M.; Werner, S. A.

    2004-07-01

    A measurement of the n- 3He coherent scattering length using neutron interferometry is reported. The result, bc =(5.8572±0.0072) fm , improves the measured precision of any single measurement of bc by a factor of eight; the previous world average, bc =(5.74±0.04) fm , now becomes bc =(5.853±0.007) fm . Measurements of the n-p , n-d , and n- 3He coherent scattering lengths have now been performed using the same technique, thus allowing one to extract the scattering length ratios: parameters that minimize systematic errors. We obtain values of bn 3He / bnp =(-1.5668±0.0021) and bnd / bnp =(-1.7828±0.0014) . Using the new world average value of bc and recent high-precision spin-dependent scattering length data also determined by neutron optical techniques, we extract new values for the bound singlet and triple scattering lengths of b0 =(9.949±0.027) fm and b1 =(4.488±0.017) fm for the n- 3He system. The free nuclear singlet and triplet scattering lengths are a0 =(7.456±0.020) fm and a1 =(3.363±0.013) fm . The coherent scattering cross section is σc =(4.305±0.007) b and the total scattering cross section is σs =(5.837±0.014) b . Comparisons of a0 and a1 to the only existing high-precision theoretical predictions for the n- 3He system, calculated using a resonating group technique with nucleon-nucleon potentials incorporating three-nucleon forces, have been performed. Neutron scattering length measurements in few-body systems are now sensitive enough to probe small effects not yet adequately treated in present theoretical models.

  18. Uranium Neutron Coincidence Collar Model Utilizing 3He

    SciTech Connect

    Siciliano, Edward R.; Rogers, Jeremy L.; Schweppe, John E.; Lintereur, Azaree T.; Kouzes, Richard T.

    2012-07-30

    The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube based alternative system in a configuration typically used for 3He-based coincidence counter applications. The specific application selected for boron-lined tube replacement in this project was one of the Uranium Neutron Coincidence Collar (UNCL) designs. This report, providing results for model development of a UNCL, is a deliverable under Task 2 of the project. The current UNCL instruments utilize 3He tubes. As the first step in developing and optimizing a boron-lined proportional counter based version of the UNCL, models of eight different 3He-based UNCL detectors currently in use were developed and evaluated. A comparison was made between the simulated results and measured efficiencies for those systems with values reported in the literature. The reported experimental measurements for efficiencies and die-away times agree to within 10%.

  19. Compressing Spin-Polarized 3He With a Modified Diaphragm Pump

    PubMed Central

    Gentile, T. R.; Rich, D. R.; Thompson, A. K.; Snow, W. M.; Jones, G. L.

    2001-01-01

    Nuclear spin-polarized 3He gas at pressures on the order of 100 kPa (1 bar) are required for several applications, such as neutron spin filters and magnetic resonance imaging. The metastability-exchange optical pumping (MEOP) method for polarizing 3He gas can rapidly produce highly polarized gas, but the best results are obtained at much lower pressure (~0.1 kPa). We describe a compact compression apparatus for polarized gas that is based on a modified commercial diaphragm pump. The gas is polarized by MEOP at a typical pressure of 0.25 kPa (2.5 mbar), and compressed into a storage cell at a typical pressure of 100 kPa. In the storage cell, we have obtained 20 % to 35 % 3He polarization using pure 3He gas and 35 % to 50 % 3He polarization using 3He-4He mixtures. By maintaining the storage cell at liquid nitrogen temperature during compression, the density has been increased by a factor of four. PMID:27500044

  20. High-pressure /sup 3/He gas scintillation neutron spectrometer

    SciTech Connect

    Derzon, M.S.; Slaughter, D.R.; Prussin, S.G.

    1985-10-01

    A high-pressure, /sup 3/He-Xe gas scintillation spectrometer has been developed for neutron spectroscopy on D-D fusion plasmas. The spectrometer exhibits an energy resolution of (121 +- 20 keV) keV (FWHM) at 2.5 MeV and an efficiency of (1.9 +- 0.4) x 10/sup -3/ (n/cm/sup 2/)/sup -1/. The contribution to the resolution (FWHM) from counting statistics is only (22 +- 3 keV) and the remainder is due predominantly to the variation of light collection efficiency with location of neutron events within the active volume of the detector.

  1. Polarized 3He as an effective neutron target for deep inelastic scattering

    NASA Astrophysics Data System (ADS)

    Johnston, Kyle

    In undergraduate physics courses, we are all taught that a proton and a neutron both have a quantity called 'spin' which has a simple value of 1/2 in units of h. It was first naively understood that this value comes from the addition of the spins of the basic constituents, quarks and gluons. However, experiments revealed that it is not enough. The value of 1/2 has yet to be reconciled with the addition of not only the spins of the constituents but also their orbital motion. Clearly, the spin structure in terms of the basic constituents needs more investigation. This thesis aims to describe the polarization and calibration of a polarized 3He target, which can be used for probing the spin structure of the neutron in terms of its constituents, quarks and gluons.

  2. Pulsed NMR in the nuclear spin ordered phases of solid 3He in a silver sinter

    NASA Astrophysics Data System (ADS)

    Millan-Chacartegui, Carmen; Schuberth, Erwin A.; Deppe, Frank; Schöttl, Stephan

    2003-05-01

    To obtain the exact spin structure of the nuclear magnetically ordered phases of solid 3He, in the BCC lattice called U2D2 and high field phase, both occurring below about 1 mK, we started a project of neutron scattering from the solid at the Hahn-Meitner Institut, Berlin. This experiment faces three main difficulties: to cool the solid to temperatures below 1 mK (or even much lower in the case of the HCP lattice), to keep it there under neutron flux, and to grow a single crystal within the sintered material needed for this purpose. As a first step we have performed pulsed NMR measurements in the ordered phases of solid 3He in a silver sinter of 700 Å particle size down to temperatures of 600 μK at various molar volumes. The samples remained in the ordered state for as long as 110 h.

  3. Measurement of the Coherent Neutron Scattering Length of 3He

    PubMed Central

    Ketter, W.; Heil, W.; Badurek, G.; Baron, M.; Loidl, R.; Rauch, H.

    2005-01-01

    By means of neutron interferometry the s-wave neutron scattering length of the 3He nucleus was re-measured at the Institut Laue-Langevin (ILL). Using a skew symmetrical perfect crystal Si-interferometer and a linear twin chamber cell, false phase shifts due to sample misalignment were reduced to a negligible level. Simulation calculations suggest an asymmetrically alternating measuring sequence in order to compensate for systematic errors caused by thermal phase drifts. There is evidence in the experiment’s data that this procedure is indeed effective. The neutron refractive index in terms of Sears’ exact expression for the scattering amplitude has been analyzed in order to evaluate the measured phase shifts. The result of our measurement, b′c = (6.000 ± 0.009) fm, shows a deviation towards a greater value compared to the presently accepted value of b′c = (5.74 ± 0.07) fm, confirming the observation of the partner experiment at NIST. On the other hand, the results of both precision measurements at NIST and ILL exhibit a serious 12σ (12 standard uncertainties) deviation, the reason for which is not clear yet.

  4. Polarization of 3He by Spin Exchange with Optically Pumped Rb and K Vapors

    NASA Astrophysics Data System (ADS)

    Ben-Amar Baranga, A.; Appelt, S.; Romalis, M. V.; Erickson, C. J.; Young, A. R.; Cates, G. D.; Happer, W.

    1998-03-01

    We report on extensive experimental measurements of the key rates that determine the efficiency for polarizing the nuclei of 3He by spin exchange with optically pumped Rb vapor. In agreement with recent theoretical predictions, we find a strong temperature dependence of the electron-spin loss rates due to 3HeRb collisions. We also find that the maximum possible efficiency for spin-exchange polarization of 3He by K is 10 times greater than for Rb.

  5. SPECIAL ISSUE DEVOTED TO THE 80TH ANNIVERSARY OF ACADEMICIAN N G BASOV'S BIRTH: An optically polarised dense 3He target as a spin filter for slow-neutron beams

    NASA Astrophysics Data System (ADS)

    Kolachevsky, Nikolai N.; Prokof'ichev, Yu V.; Skoi, V. R.; Sobel'man, Igor I.; Sorokin, Vadim N.

    2003-01-01

    The possibility of polarising 3He and preserving the polarisation in an external magnetic field of 0.05 Oe is demonstrated experimentally. A neutron filter with an extremely weak guiding field is fabricated for obtaining polarised neutron beams. The degree of polarisation equal to 25% was obtained for 0.025-eV neutrons. Some fields of application of other polarised noble gases are considered. The cross section for cross-relaxation of nuclear polarisation in the 129Xe — 131Xe mixture is estimated.

  6. The First Measurement of Neutron Transversity on a Transversely Polarized 3He Target

    SciTech Connect

    Yi Qiang

    2009-12-01

    We recently measured the neutron target single spin asymmetry in the semi-inclusive deep inelastic 3He (e,e',pi+/-)X reactions with a transversely polarized 3He target. The experiment was performed in Hall A at Jefferson Lab from October 2008 to February 2009. Pions were detected in the high-resolution spectrometer in coincidence with scattered electrons detected by the BigBite spectrometer. The kinematic coverage focuses on the valence quark region, x = 0.1 - 0.4, at Q2 = 1-3 (GeV/c)2. With good particle identifications using a RICH detector and an aerogel Cherenkov counter, data on kaons were obtained at the same time. The data from this experiment, when combined with the world data, will provide constraints on the Transversity and Sivers distributions on both u-quark and d-quark in the valence quark region.

  7. Nuclear spin heat capacity of 3He adsorbed on graphite

    NASA Astrophysics Data System (ADS)

    Greywall, Dennis S.

    1989-10-01

    The heat capacity of 3He adsorbed on graphite has been measured for films between one and five atomic layers and for temperatures between 2 and 200 mK. These results are compared with recent magnetization data which also show several anomalies in this coverage regime. Prior to third layer promotion the second layer is found to solidify into a registered structure with unusual propertis. This contradicts the model proposed to explain the NMR measurements.

  8. Neutron dosimetry at commercial nuclear plants. Final report of Subtask C: /sup 3/He neutron spectrometer

    SciTech Connect

    Brackenbush, L.W.; Reece, W.D.; Tanner, J.E.

    1984-09-01

    In commercial nuclear power plants, personnel routinely enter containment for maintenance and inspections while the reactor is operating and can be exposed to intense neutron fields. The low-energy neutron fields found in reactor containment cause problems in proper interpretation of TLD-albedo dosimeters and survey instrument readings. This report describes a technique that can aid plant health physicists to improve the accuracy of personnel neutron dosimetry programs. A /sup 3/He neutron spectrometer can be used to measure neutron energy spectra and determine dose equivalent rates at work locations inside containment. Energy correction factors for TLD-albedo dosimeters can be determined from the measured spectra if the dosimeter energy response is known, or from direct measurements with dosimeters placed on phantoms at locations where the dose equivalent rate has been measured. This report describes how to assemble a spectrometer system using only commercially available components, how to use it for reactor energy spectrum measurements, and how to analyze the data and interpret the results. Both /sup 3/He and multisphere spectrometers were used to measure neutron energy spectra and dose equivalent at three PWRs and one BWR. In general, the /sup 3/He spectrometer measures higher dose equivalent rates than the multisphere spectrometer. In the energy range from 10 keV to 1 MeV, the dose equivalents measured by the /sup 3/He spectrometer and multisphere spectrometer agree within about 35% for the spectra measured.

  9. On the limits of spin-exchange optical pumping of {sup 3}He

    SciTech Connect

    Chen, W. C. Ye, Q.; Gentile, T. R.; Walker, T. G.; Babcock, E.

    2014-07-07

    We have obtained improvement in the {sup 3}He polarization achievable by spin-exchange optical pumping (SEOP). These results were primarily obtained in large neutron spin filter cells using diode bar lasers spectrally narrowed with chirped volume holographic gratings. As compared to our past results with lasers narrowed with diffraction gratings, we have observed between 5% and 11% fractional increase in the {sup 3}He polarization P{sub He}. We also report a comparable improvement in P{sub He} for two small cells, for which we would not have expected an increase from improved laser performance. In particular, prior extensive studies had indicated that the alkali-metal polarization was within 3% of unity in one of these cells. These results have impact on understanding the maximum P{sub He} achievable by SEOP, whether the origin of the improvement is from increased alkali-metal polarization or decreased temperature-dependent relaxation. We conclude that the most likely explanation for the improvement in P{sub He} is increased alkali-metal polarization. We have observed P{sub He} of between 0.80 and 0.85 in several large cells, which marks a new precedent for the polarization achievable by SEOP.

  10. On the limits of spin-exchange optical pumping of 3 He

    NASA Astrophysics Data System (ADS)

    Gentile, T. R.; Chen, W. C.; Ye, Q.; Walker, T. G.; Babcock, E.

    2015-04-01

    We have obtained improvement in the 3 He polarization achievable by spin-exchange optical pumping (SEOP). These results were primarily obtained in large neutron spin filter cells using diode bar lasers spectrally narrowed with chirped volume holographic gratings. As compared to our past results with lasers narrowed with diffraction gratings, we have observed between 5% and 11% fractional increase in the 3 He polarization PHe. We also report a comparable improvement in PHe for two small cells, for which we would not have expected an increase from improved laser performance. In particular, prior extensive studies had indicated that the alkali-metal polarization was within 3% of unity in one of these cells. These results have impact on understanding the maximum PHe achievable by SEOP, whether the origin of the improvement is from increased alkali-metal polarization or decreased temperature-dependent relaxation. We have observed PHe of between 0.80 and 0.85 in several large cells, which marks a new precedent for the polarization achievable by SEOP. Recently we have obtained PHe as high as 0.88 with increased laser power. We will discuss these results and tests performed to understand their origin.

  11. Magnetization studies of the nuclear spin ordered phases of solid 3He in silver sinters

    NASA Astrophysics Data System (ADS)

    Schuberth, E. A.; Kath, M.; Tassini, L.; Millan-Chacartegui, C.

    2005-08-01

    Solid 3He, in the bcc lattice between 34 and 100 bar, exhibits two nuclear magnetic ordered phases in the sub-mK temperature range, the so called U2D2 low (magnetic) field phase and the “high field phase” above 0.4 T. To determine the exact spin structure of these phases we started a project of neutron scattering from the ordered solid in collaboration with the Hahn-Meitner Institute, Berlin, and other European and US groups. For this experiment it is crucial to grow a single crystal within the sinter needed for cooling the solid to temperatures of the order of 500 μK (or even twenty times lower in the case of the hcp lattice which is formed above 100 bar) and to keep it there long enough to measure a magnetic neutron reflection. We studied the growth of crystals in Ag sinters of different pore size and with different growth speeds to find an optimal way to obtain single crystalline samples. As a first diagnostic step we performed pulsed NMR measurements in the ordered phases of solid 3He in a sinter of 2700 Å particle size down to temperatures of 450 μK at various molar volumes. We could keep the samples in the ordered state for as long as 140 h. The second method we used was SQUID magnetometry. For the low field phase TN was indicated by a drop of the intensity, both in the NMR signal and in the dc magnetization, whereas in the high field phase an increase of about 30% was observed below the ordering temperature. For the fabrication of the sinters a packing fraction of 50% and subsequent annealing proved to be very favorable to obtain cold ordered solid. Furthermore, we find that a paramagnetic surface contribution from a few monolayers of 3He exists down to 500 μK in addition to the bulk magnetization.

  12. Spin Correlation Parameter Cyy of p + 3He Elastic Backward Scattering at Intermediate Energy

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Hatanaka, K.; Adachi, T.; Itoh, K. F. K.; Kawabata, T.; Kudoh, T.; Ohira, H. M. H.; Okamura, H.; Sagara, K.; Sasamoto, Y. S. Y.; Yoshida, Y. S. H. P.; Suda, K.; Tomiyama, Y. T. A. T. M.; Uesaka, M. U. T.; Wakasa, T.; Wakui, T.

    2005-08-01

    It is possible to use nucleon-nucleus scattering as a probe of the spin structure of nuclei, since target related observables are extremely sensitive to small spin-dependent parts of the target wave function. In addition, one can gain information about the nucleon-nucleus reaction mechanism, the spin dependence of the nucleon-nucleon interaction in the nuclear medium, and off-shell behavior of the nucleon-nucleon amplitudes. For 3He(p,3He)p elastic backward scattering (EBS), only a small amount of data exists for the differential cross-section and none exists for spin-dependent observables. We have developed a spin-exchange polarised 3He target and measured the spin correlation parameter Cyy at 200, 300, and 400 MeV.

  13. Spin Correlation Parameter Cyy of p + 3He Elastic Backward Scattering at Intermediate Energy

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Hatanaka, K.; Kobushkin, A. P.; Adachi, T.; Fujita, K.; Itoh, K.; Kawabata, T.; Kudoh, T.; Matsubara, H.; Ohira, H.; Okamura, H.; Sagara, K.; Sakemi, Y.; Sasamoto, Y.; Shimbara, Y.; Yoshida, H. P.; Suda, K.; Tameshige, Y.; Tamii, A.; Tomiyama, M.; Uchida, M.; Uesaka, T.; Wakasa, T.; Wakui, T.

    2007-01-01

    It is possible to use nucleon-nucleus scattering as a probe of the spin structure of the nuclei since target related observables are extremely sensitive to spin dependent parts of the target wave function. In addition, one can gain information about the nucleon-nucleus reaction mechanism, the spin dependent nucleon-nucleon interaction in the nuclear medium, and off-shell behavior of the nucleon-nucleon amplitudes. For 3He(p,3He)p elastic backward scattering, only small amount of data points exist for the differential cross section and no data exist for spin dependent observables. We developed a spin exchange type polarized 3He target and measured the spin correlation parameter Cyy at 200, 300, and 400 MeV.

  14. Progress Towards the Detection of Faraday Rotation on Spin Polarized 3He

    NASA Astrophysics Data System (ADS)

    Abney, Josh; Broering, Mark; Korsch, Wolfgang

    2016-03-01

    Off-resonance Faraday rotation can offer a new method to monitor the nuclear spin polarization of a dense 3He target and gain access to new information about the magnetic polarizability of the 3He nucleus. The interaction of the polarization state of light with the nuclear spin of the helium atom is very weak and has never been detected. A sensitive triple modulation technique has been developed which can detect the expected rotation angle on the order of 100 nrad. Once a Faraday rotation signal is observed, the next step is to separate the magnetic and electric contributions to the rotation by utilizing their different frequency dependencies. Recent studies involved optimizing several parameters which impact 3He target polarization. Progress towards detecting nuclear spin optical rotation on 3He will be reported. This research is supported by DOE Grant DE-FG02-99ER41101.

  15. 3He and BF 3 neutron detector pressure effect and model comparison

    NASA Astrophysics Data System (ADS)

    Lintereur, Azaree; Conlin, Kenneth; Ely, James; Erikson, Luke; Kouzes, Richard; Siciliano, Edward; Stromswold, David; Woodring, Mitchell

    2011-10-01

    Radiation detection systems for homeland security applications must possess the capability of detecting both gamma rays and neutrons. The radiation portal monitor systems that are currently deployed use a plastic scintillator for detecting gamma rays and 3He gas-filled proportional counters for detecting neutrons. Proportional counters filled with 3He are the preferred neutron detectors for use in radiation portal monitor systems because 3He has a large neutron cross-section, is relatively insensitive to gamma-rays, is neither toxic nor corrosive, can withstand extreme environments, and can be operated at a lower voltage than some of the alternative proportional counters. The amount of 3He required for homeland security and science applications has depleted the world supply and there is no longer enough available to fill the demand. Thus, alternative neutron detectors are being explored. Two possible temporary solutions that could be utilized while a more permanent solution is being identified are reducing the 3He pressure in the proportional counters and using boron trifluoride gas-filled proportional counters. Reducing the amount of 3He required in each of the proportional counters would decrease the rate at which 3He is being used; not enough to solve the shortage, but perhaps enough to increase the amount of time available to find a working replacement. Boron trifluoride is not appropriate for all situations as these detectors are less sensitive than 3He, boron trifluoride gas is corrosive, and a much higher voltage is required than what is used with 3He detectors. Measurements of the neutron detection efficiency of 3He and boron trifluoride as a function of tube pressure were made. The experimental results were also used to validate models of the radiation portal monitor systems.

  16. Packed Powder as Superleak for Spin Pump Experiments in Superfluid 3He A1

    NASA Astrophysics Data System (ADS)

    Kamada, N.; Yamaguchi, A.; Motoyama, G.; Sumiyama, A.; Aoki, Y.; Okuda, Y.; Kojima, H.

    2014-04-01

    Experimental exploration of highly spin-polarized states of liquid 3He by applying external magnetic field is limited by the availability of static magnetic field. In the "ferromagnetic" superfluid A1 phase of liquid 3He there is an alternate method for boosting spin-polarization by the process of spin pumping without requiring such high magnetic field. The spin pumping in the A1 phase takes advantage of a superleak (SL) acting simultaneously as a filter for both entropy and spin. The spin pump technique that uses the SL-spin filter and a mechanical actuator enables us to directly boost polarization of 3He. The amount of enhancement of spin polarization has been limited so far. We are now developing a new type of SL filter made of packed aluminum oxide powder (referred as PAP-SL), in order to achieve greater enhancement of spin polarization. Several kinds of the PAP-SL filter were constructed by pressing aluminum oxide powders into a cylinder holder. The packed structures were carefully characterized by a flow-rate-measurement, X-ray tomography, and mercury intrusion porosimetry. The preliminary result shows that the PAP-SL works as SL filter for the superfluid 3He.

  17. Recent Spin Pump Experiments on Superfluid 3He-A1

    NASA Astrophysics Data System (ADS)

    Yamaguchi, A.; Kamada, N.; Motoyama, G.; Sumiyama, A.; Aoki, Y.; Okuda, Y.; Kubota, M.; Kojima, H.

    2013-05-01

    The superfluid 3He A1 phase, containing a spin-polarized condensate allows us to explore the dynamics of superfluid spin current. In the mechano-spin effect (MSE), a mechanically applied pressure gradient and a superleak-spin filter enable one to directly boost spin polarization of 3He in a small chamber. We are developing new apparatus for achieving greater enhancement of spin density. A development of a new-type 3He-hydraulic actuator has been already reported. We present here the construction of new-type of superleak-spin-filter made of packed powder aluminum oxide (referred as PAP-SL). The PAP-SL is popular in the study of superfluid 4He, but has not been established for that of the superfluid 3He. The attempt to construct the PAP-SL for the spin pump experiment was made by using aluminum oxide powder with nominal 1 μm powder diameter and with packing fraction of 40 %. Before executing the experiment, the nuclear demagnetization cryostat of ISSP, Univ. Tokyo which has been used for this experimental activity, was heavily damaged by the 2011 Great East Japan (Higashi Nihon) Earthquake. The repair work and earthquake damage protection strengthening has just been accomplished.

  18. Magnetization and spin diffusion of liquid {sup 3}He in aerogel

    SciTech Connect

    Sauls, J. A.; Bunkov, Yu.M.; Collin, E.; Godfrin, H.; Sharma, P.

    2005-07-01

    We report theoretical calculations and experimental measurements of the normal-state spin diffusion coefficient of {sup 3}He in aerogel, including both elastic and inelastic scattering of {sup 3}He quasiparticles, and compare these results with data for {sup 3}He in 98% porous silica aerogel. This analysis provides a determination of the elastic mean free path within the aerogel. Measurements of the magnetization of the superfluid phase in the same aerogel samples provide a test of the theory of pairbreaking and magnetic response of low-energy excitations in the 'dirty' B phase of {sup 3}He in aerogel. A consistent interpretation of the data for the spin-diffusion coefficient, magnetization, and superfluid transition temperature is obtained by including correlation effects in the aerogel density.

  19. A compact spin-exchange optical pumping system for 3He polarization based on a solenoid coil, a VBG laser diode, and a cosine theta RF coil

    NASA Astrophysics Data System (ADS)

    Lee, Sungman; Kim, Jongyul; Moon, Myung Kook; Lee, Kye Hong; Lee, Seung Wook; Ino, Takashi; Skoy, Vadim R.; Lee, Manwoo; Kim, Guinyun

    2013-02-01

    For use as a neutron spin polarizer or analyzer in the neutron beam lines of the HANARO (High-flux Advanced Neutron Application ReactOr) nuclear research reactor, a 3He polarizer was designed based on both a compact solenoid coil and a VBG (volume Bragg grating) diode laser with a narrow spectral linewidth of 25 GHz. The nuclear magnetic resonance (NMR) signal was measured and analyzed using both a built-in cosine radio-frequency (RF) coil and a pick-up coil. Using a neutron transmission measurement, we estimated the polarization ratio of the 3He cell as 18% for an optical pumping time of 8 hours.

  20. Progress Towards the Detection of Faraday Rotation on Spin Polarized 3He

    NASA Astrophysics Data System (ADS)

    Abney, Joshua; Broering, Mark; Korsch, Wolfgang

    2016-05-01

    Off-resonance Faraday rotation can offer a method to measure the nuclear spin optical rotation of the 3 He nucleus and gain access to new information about the atomic polarizability of the Helium atom. The interaction of the polarization state of light with the nuclear spin of the helium atom is very weak and has never been detected. A sensitive triple modulation technique has been developed which can detect the expected rotation angle on the order of 100 nrad. Once a Faraday rotation signal is observed, the next step is to separate the magnetic and electric contributions to the rotation by utilizing their different frequency dependencies. Recent studies involved optimizing several parameters which impact 3 He target polarization. Progress towards detecting nuclear spin optical rotation on 3 He will be reported. This research is supported by DOE Grant DE-FG02-99ER41101.

  1. [sup 3]He neutron detector performance in mixed neutron gamma environments

    SciTech Connect

    Johnson, N. H.; Beddingfield, D. H.

    2002-01-01

    A test program of the performance of 3He neutron proportional detectors with varying gas pressures, and their response to lligh level gamma-ray exposure in a mixed neutrodgamma environment, ha$ been performed Our intent was to identie the optimal gas pressure to reduce the gamma-ray sensitivity of these detectors. These detectors were manufxtured using materials to minimize their gamma response. Earlier work focused on 3He fill pressures of four atmospheres and above, whereas the present work focuses on a wider range of pressures. Tests have shown that reducing the .filling pressure will M e r increase the gamma-ray dose range in which the detectors can be operated.

  2. Low-temperature instability of uniform spin precession in the B phase of pure {sup 3}He and {sup 3}He in an aerogel

    SciTech Connect

    Surovtsev, E. V. Fomin, I. A.

    2010-08-15

    The magnetic-field dependences of the threshold temperature of the low-temperature instability of uniform spin precession in pure {sup 3}He-B and {sup 3}He-B in an aerogel have been determined for the bulk mechanism. These dependences appear to be different. The theoretical dependence of the threshold temperature for the pure case has been compared with the experimental dependence. The threshold temperature of the instability for {sup 3}He in the aerogel has been estimated for typical experimental conditions.

  3. Polarized 3He Gas Circulating Technologies for Neutron Analyzers

    SciTech Connect

    Watt, David; Hersman, Bill

    2014-12-10

    We describe the development of an integrated system for quasi-continuous operation of a large volume neutron analyzer. The system consists of a non-magnetic diaphragm compressor, a prototype large volume helium polarizer, a surrogate neutron analyzer, a non-depolarizing gas storage reservoir, a non-ferrous valve manifold for handling gas distribution, a custom rubidium-vapor gas return purifier, and wire-wound transfer lines, all of which are immersed in a two-meter external magnetic field. Over the Phase II period we focused on three major tasks required for the successful deployment of these types of systems: 1) design and implementation of gas handling hardware, 2) automation for long-term operation, and 3) improvements in polarizer performance, specifically fabrication of aluminosilicate optical pumping cells. In this report we describe the design, implementation, and testing of the gas handling hardware. We describe improved polarizer performance resulting from improved cell materials and fabrication methods. These improvements yielded valved 8.5 liter cells with relaxation times greater than 12 hours. Pumping this cell with 1500W laser power with 1.25nm linewidth yielded peak polarizations of 60%, measured both inside and outside the polarizer. Fully narrowing this laser to 0.25nm, demonstrated separately on one stack of the four, would have allowed 70% polarization with this cell. We demonstrated the removal of 5 liters of polarized helium from the polarizer with no measured loss of polarization. We circulated the gas through a titanium-clad compressor with polarization loss below 3% per pass. We also prepared for the next phase of development by refining the design of the polarizer so that it can be engineer-certified for pressurized operation. The performance of our system far exceeds comparable efforts elsewhere.

  4. Spin Diffusion Coefficient of A1-PHASE of Superfluid 3He at Low Temperatures

    NASA Astrophysics Data System (ADS)

    Afzali, R.; Pashaee, F.

    The spin diffusion coefficient tensor of the A1-phase of superfluid 3He at low temperatures and melting pressure is calculated using the Boltzmann equation approach and Pfitzner procedure. Then considering Bogoliubov-normal interaction, we show that the total spin diffusion is proportional to 1/T2, the spin diffusion coefficient of superfluid component D\\uparrowxzxz is proportional to T-2, and the spin diffusion coefficient of super-fluid component D\\uparrowxxxx (=D\\uarrowxyxy) is independent of temperature. Furthermore, it is seen that superfluid components play an important role in spin diffusion of the A1-phase.

  5. Gas cells for 3He hyperpolarized via spin-exchange optical pumping

    NASA Astrophysics Data System (ADS)

    Kim, W.; Stepanyan, S. S.; Kim, A.; Tan, J. A.; Woo, S.

    2016-01-01

    We present a device for the production of hyperpolarized 3He, which is widely used in spinrelated nuclear physics research. Spin-exchange optical pumping (SEOP) is employed to polarize 3He enclosed in a circular borosilicate glass cell suitable not only for the production of polarized gas but also for its storage. The portable glass cell can, thus, be transported to any other research facility. The glass cell can be refilled several times. Special attention is given to the preparation and the filling of the cell to minimize the impurities on its walls and in the gas. We employ glass tubes with shorter lengths and larger diameters in the gas-filling system to achieve the improvement in the air flow necessary to obtain purer polarized 3He samples. The cell is prepared, and after it has been filled with rubidium (Rb) and 3He-N2 mixture, it is sealed under high vacuum conditions. The cell containing the mixture is exposed to circularly-polarized laser light with a wavelength of 795 nm at temperatures of 180 - 220 °C for SEOP. The polarization of 3He is measured via nuclear magnetic resonance (NMR). We obtained 40% polarized 3He in less than 15 hours and 50% in about 25 hours. The longitudinal relaxation time T 1 of the polarized 3He we measured was about 58 hours.

  6. The Effect Of Neutron Attenuation On Power Deposition In Nuclear Pumped 3He-Lasers

    NASA Astrophysics Data System (ADS)

    Çetin, Füsun

    2007-04-01

    Nuclear-pumped lasers (NPLs) are driven by the products of nuclear reactions and directly convert the nuclear energy to directed optical energy. Pumping gas lasers by nuclear reaction products has the advantage of depositing large energies per reaction. The need for high laser power output implies high operating pressure. In the case of volumetric excitation by 3He(n, p)3H reactions, however, operation at high pressure (more than a few atm) causes excessive neutron attenuation in the 3He gas. This fact adversely effects on energy deposition and, hence, laser output power and beam quality. Here, spatial and temporal variations of neutron flux inside a closed 3He -filled cylindrical laser tube have been numerically calculated for various tube radii and operating pressures by using a previously reported dynamic model for energy deposition. Calculations are made by using ITU TRIGA Mark II Reactor as the neutron source. The effects of neutron attenuation on power deposition are examined.

  7. The Effect Of Neutron Attenuation On Power Deposition In Nuclear Pumped 3He-Lasers

    SciTech Connect

    Cetin, Fuesun

    2007-04-23

    Nuclear-pumped lasers (NPLs) are driven by the products of nuclear reactions and directly convert the nuclear energy to directed optical energy. Pumping gas lasers by nuclear reaction products has the advantage of depositing large energies per reaction. The need for high laser power output implies high operating pressure. In the case of volumetric excitation by 3He(n, p)3H reactions, however, operation at high pressure (more than a few atm) causes excessive neutron attenuation in the 3He gas. This fact adversely effects on energy deposition and, hence, laser output power and beam quality. Here, spatial and temporal variations of neutron flux inside a closed 3He -filled cylindrical laser tube have been numerically calculated for various tube radii and operating pressures by using a previously reported dynamic model for energy deposition. Calculations are made by using ITU TRIGA Mark II Reactor as the neutron source. The effects of neutron attenuation on power deposition are examined.

  8. Polarization Induced Spin Wave Damping in Spin Polarized Liquid 3He 4He

    NASA Astrophysics Data System (ADS)

    Perisanu, Sorin; Vermeulen, Gerard

    2007-08-01

    We have measured the temperature and polarization dependence of Silin spin wave spectra in a saturated 3He 4He mixture with a concentration of 9.4% at a pressure of 8 bars. The mixture has been cooled and polarized by a Leiden dilution refrigerator to temperatures in the range 10 15 mK and polarizations as high as 9.2% corresponding to 3.4 times the equilibrium polarization of 2.7% in the external magnetic field of 11.36 T. The analysis takes into account the dipolar interactions and results in the relaxation time τ ⊥ and spin diffusion constant D ⊥ . We find that τ ⊥ and D ⊥ are proportional to 1/(T2+mathcal{A}2T_{a0}2) where T is the temperature, mathcal{A} is the polarization enhancement factor and T a0 is the anisotropy temperature for the mixture at equilibrium in the external field. Our result T a0=3.66±0.14 mK is 30% higher than the theoretical prediction for very dilute mixtures and is evidence for the existence of polarization induced relaxation of transverse spin currents.

  9. SQUID measurements of remanent magnetisation in refillable 3He spin-filter cells (SFC)

    NASA Astrophysics Data System (ADS)

    Hutanu, V.; Rupp, A.; Sander-Thömmes, T.

    2007-07-01

    A strong influence of external magnetic fields on the relaxation time constant T1 of glass cells serving as reservoirs for polarised 3He, observed for various alkali metal-coated cells made of different glass types, was initially associated with the presence of a large number of ferromagnetic clusters on the glass surface. Later experiments showed the presence of the so-called “ T1 hysteresis” phenomenon with a similar distinctiveness also in uncoated cells made of pure synthetic quartz glass. It suggests that the origin of such a relaxation is a macroscopic magnetisation in the bulk of the cell. We present the results of a multi-SQUID system investigation on magnetised and non-magnetised quartz glass cells, Cs coated as well as bare wall, to be used as neutron spin filters at HMI Berlin. The presence of a macroscopic remanent magnetic moment in the cells after their exposition to external magnetic fields has been experimentally shown. More than 80% of the remanent magnetic moment of the magnetised cells was found to be concentrated in the region of the glass valves. SQUID measurements reveal the existence of some remanent magnetisation in all valve parts and also in the vacuum grease, but most magnetic are the plastic parts and the O-ring. Different valve and sealing types have been compared in order to find the less magnetisable one.

  10. High-sensitivity measurement of 3He-4He isotopic ratios for ultracold neutron experiments

    NASA Astrophysics Data System (ADS)

    Mumm, H. P.; Huber, M. G.; Bauder, W.; Abrams, N.; Deibel, C. M.; Huffer, C. R.; Huffman, P. R.; Schelhammer, K. W.; Janssens, R.; Jiang, C. L.; Scott, R. H.; Pardo, R. C.; Rehm, K. E.; Vondrasek, R.; Swank, C. M.; O'Shaughnessy, C. M.; Paul, M.; Yang, L.

    2016-06-01

    Research efforts ranging from studies of solid helium to searches for a neutron electric dipole moment require isotopically purified helium with a ratio of 3He to 4He at levels below that which can be measured using traditional mass spectroscopy techniques. We demonstrate an approach to such a measurement using accelerator mass spectroscopy, reaching the 10-14 level of sensitivity, several orders of magnitude more sensitive than other techniques. Measurements of 3He/4He in samples relevant to the measurement of the neutron lifetime indicate the need for substantial corrections. We also argue that there is a clear path forward to sensitivity increases of at least another order of magnitude.

  11. Theory of spin-exchange optical pumping of 3He and 129Xe

    NASA Astrophysics Data System (ADS)

    Appelt, S.; Baranga, A. Ben-Amar; Erickson, C. J.; Romalis, M. V.; Young, A. R.; Happer, W.

    1998-08-01

    We present a comprehensive theory of nuclear spin polarization of 3He and 129Xe gases by spin-exchange collisions with optically pumped alkali-metal vapors. The most important physical processes considered are (1) spin-conserving spin-exchange collisions between like or unlike alkali-metal atoms; (2) spin-destroying collisions of the alkali-metal atoms with each other and with buffer-gas atoms; (3) electron-nuclear spin-exchange collisions between alkali-metal atoms and 3He or 129Xe atoms; (4) spin interactions in van der Waals molecules consisting of a Xe atom bound to an alkali-metal atom; (5) optical pumping by laser photons; (6) spatial diffusion. The static magnetic field is assumed to be small enough that the nuclear spin of the alkali-metal atom is well coupled to the electron spin and the total spin is very nearly a good quantum number. Conditions appropriate for the production of large quantities of spin-polarized 3He or 129Xe gas are assumed, namely, atmospheres of gas pressure and nearly complete quenching of the optically excited alkali-metal atoms by collisions with N2 or H2 gas. Some of the more important results of this work are as follows: (1) Most of the pumping and relaxation processes are sudden with respect to the nuclear polarization. Consequently, the steady-state population distribution of alkali-metal atoms is well described by a spin temperature, whether the rate of spin-exchange collisions between alkali-metal atoms is large or small compared to the optical pumping rate or the collisional spin-relaxation rates. (2) The population distributions that characterize the response to sudden changes in the intensity of the pumping light are not described by a spin temperature, except in the limit of very rapid spin exchange. (3) Expressions given for the radio-frequency (rf) resonance linewidths and areas can be used to make reliable estimates of the local spin polarization of the alkali-metal atoms. (4) Diffusion effects for these high

  12. Boron-coated straws as a replacement for 3He-based neutron detectors

    NASA Astrophysics Data System (ADS)

    Lacy, Jeffrey L.; Athanasiades, Athanasios; Sun, Liang; Martin, Christopher S.; Lyons, Tom D.; Foss, Michael A.; Haygood, Hal B.

    2011-10-01

    US and international government efforts to equip major seaports with large area neutron detectors, aimed to intercept the smuggling of nuclear materials, have precipitated a critical shortage of 3He gas. It is estimated that the annual demand of 3He for US security applications alone is more than the worldwide supply. This is strongly limiting the prospects of neutron science, safeguards, and other applications that rely heavily on 3He-based detectors. Clearly, alternate neutron detection technologies that can support large sensitive areas, and have low gamma sensitivity and low cost must be developed. We propose a low-cost technology based on long copper tubes (straws), coated on the inside with a thin layer of 10B-enriched boron carbide ( 10B 4C). In addition to the high abundance of boron on Earth and low cost of 10B enrichment, the boron-coated straw (BCS) detector offers distinct advantages over conventional 3He-based detectors, and alternate technologies such as 10BF 3 tubes and 10B-coated rigid tubes. These include better distribution inside moderator assemblies, many-times faster electronic signals, no pressurization, improved gamma-ray rejection, no toxic or flammable gases, and ease of serviceability. We present the performance of BCS detectors dispersed in a solid plastic moderator to address the need for portal monitoring. The design adopts the outer dimensions of currently deployed 3He-based monitors, but takes advantage of the small BCS diameter to achieve a more uniform distribution of neutron converter throughout the moderating material. We show that approximately 63 BCS detectors, each 205 cm long, distributed inside the moderator, can match or exceed the detection efficiency of typical monitors fitted with a 5 cm diameter 3He tube, 187 cm long, pressurized to 3 atm.

  13. Effect of temperature on performance of {sup 3}He filled neutron proportional counters

    SciTech Connect

    Desai, Shraddha S.

    2014-04-24

    Neutron detectors used for cosmic neutron monitoring and various other applications are mounted in hostile environment. It is essential for detectors to sustain extreme climatic conditions, such as extreme temperature and humidity. Effort is made to evaluate the performance of detectors in extreme temperature in terms of pulse height distribution and avalanche formation. Neutron detectors filled with {sup 3}He incorporate an additive gas with quantity optimized for a particular application. Measurements are performed on neutron detectors filled with {sup 3}He and stopping gases Kr and CF{sub 4}. Detector performance for these fill gas combinations in terms of pulse height distribution is evaluated. Gas gain and Diethorn gas constants measured and analyzed for the microscopic effect on pulse formation. Results from these investigations are presented.

  14. Fast-Neutron Spectrometry Using a 3He Ionization Chamber and Digital Pulse Shape Analysis

    SciTech Connect

    D. L. Chichester; J. T. Johnson; E. H. Seabury

    2010-05-01

    Digital pulse shape analysis (dPSA) has been used with a Cuttler-Shalev type 3He proportional counter to measure the fast neutron spectra of bare 252Cf and 241AmBe neutron sources. Measurements have also been made to determine the attenuated fast neutron spectra of 252Cf shielded by several materials including water, graphite, liquid nitrogen, magnesium, and tungsten. Rise-time dPSA has been employed using the common rise-time approach for analyzing n +3He ? 1H + 3H ionization events and a new approach has been developed to improve the fidelity of these measurements. Simulations have been performed for the different experimental arrangements and are compared, demonstrating general agreement between the dPSA processed fast neutron spectra and predictions.

  15. Search for Spin-Dependent Short-Range Interaction with an 3He/129Xe Clock Comparison Experiment

    NASA Astrophysics Data System (ADS)

    Tullney, Kathlynne; Heil, Werner; Karpuk, Sergei; Sobolev, Yuri; Allmendinger, Fabian; Schmidt, Ulrich

    2016-02-01

    We performed an experiment to search for a new spin-dependent P- and T-violating nucleon-nucleon interaction σ→ ṡr̂ which is mediated by light pseudoscalar bosons such as axions or axionlike particles. This interaction causes a shift Δν in the precession frequency of nuclear spin polarized gases in the presence of an unpolarized mass. In order to measure this frequency shift a 3He/129Xe comagnetometer was used which is based on the detection of free precession of 3He and 129Xe nuclear spins using SQUIDs as detectors. For the upper limit of Δνsp we obtained 7.1nHz. With this value, an upper limit of the scalar-pseudoscalar coupling of the axion to the spin of a bound neutron could be deduced within the axion mass window. For axion masses between 2 and 500μeV, the laboratory upper bounds were improved by up to 4 orders of magnitude.

  16. Precision measurement of the neutron magnetic form factor from {sup 3}He(e, e')

    SciTech Connect

    Dipangkar Dutta

    2000-12-12

    A precision measurement of the inclusive quasielastic transverse asymmetry A{sub T'} from {sup 3}He(e, e') was completed recently at Hall A at Jefferson Lab (E95-001). The preliminary results on the neutron magnetic form factor at low Q{sup 2} are presented here.

  17. Optical Pumping Spin Exchange {sup 3}He Gas Cells for Magnetic Resonance Imaging

    SciTech Connect

    Kim, W.; Stepanyan, S. S.; Kim, A.; Jung, Y.; Woo, S.; Yurov, M.; Jang, J.

    2009-08-04

    We present a device for spin-exchange optical pumping system to produce large quantities of polarized noble gases for Magnetic Resonance Imaging (MRI). A method and design of apparatus for pumping the polarization of noble gases is described. The method and apparatus enable production, storage and usage of hyperpolarized noble gases for different purposes, including Magnetic Resonance Imaging of human and animal subjects. Magnetic imaging agents breathed into lungs can be observed by the radio waves of the MRI scanner and report back physical and functional information about lung's health and desease. The technique known as spin exchange optical pumping is used. Nuclear magnetic resonance is implemented to measure the polarization of hyperpolarized gas. The cells prepared and sealed under high vacuum after handling Alkali metals into the cell and filling with the {sup 3}He-N{sub 2} mixture. The cells could be refilled. The {sup 3}He reaches around 50% polarization in 5-15 hours.

  18. Lithium glass scintillator neutron detector as an improved alternative to the standard 3 he proportional counter

    SciTech Connect

    Vladimir Popov, Pavel Degtiarenko

    2011-06-01

    Lithium glass scintillator made from 6Li-enriched substrate is a well known for its neutron detection capability. In spite of neutron interaction, cross section of 6Li happens to be lower than that of 3He. However, the neutron detection efficiency could be higher due to higher volume content of 6Li nuclear in the solid scintillator vs. gas filled proportional counter. At the same time, as lithium glass is sensitive to gamma and charge particle radiation, non-neutron radiation discrimination is required. Our detector is composed of two equal-size cylindrical Li(Ce) glass scintillators. The first one is high-sensitive to thermal neutrons GS-20 (6Li doped), the second one is GS-30 (7Li doped) type Scint-Gobain made lithium glass scintillator. Each of scintillators is coupled with R7400U Hamamatsu subminiature photomultiplier tube, and all assembly is fitted into NP100H 3He tube size. 6Li absorbs thermal neutrons releasing alpha particles and triton with 4.8 MeV total energy deposit inside the scintillator (equivalent to about ~1.3 MeV gamma energy depositions). Because 7Li isotope does not absorb thermal neutrons, and the physical properties of the two scintillators are virtually identical, the difference between these two scintillators could be used to provide neutron dose rate information. Results of study of neutron detector assembled of two Li(Ce) scintillators and NP100H moderator are presented

  19. Status Summary of 3He and Neutron Detection Alternatives for Homeland Security

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.

    2010-04-28

    This is a short summary whitepaper on results of our alternatives work: Neutron detection is an important aspect of interdiction of radiological threats for homeland security purposes since plutonium, a material used for nuclear weapons, is a significant source of fission neutrons [Kouzes 2005]. Because of the imminent shortage of 3He, which is used in the most commonly deployed neutron detectors, a replacement technology for neutron detection is required for most detection systems in the very near future [Kouzes 2009a]. For homeland security applications, neutron false alarms from a detector can result in significant impact. This puts a strong requirement on any neutron detection technology not to generate false neutron counts in the presence of a large gamma ray-only source [Kouzes et al. 2008].

  20. 3He comagnetometer readout using SQUIDs in the neutron electric dipole moment (nEDM) experiment at SNS

    NASA Astrophysics Data System (ADS)

    Clayton, Steven; Kim, Young; nEDM Collaboration

    2013-04-01

    The nEDM collaboration is developing a new experiment to measure the neutron's electric dipole moment to ~10-28 e-cm. A non-zero neutron EDM would be the first observation of CP violation in a baryon containing only light quarks, while a null result would be inconsistent with predictions from most variants of supersymmetry. The experiment will measure the difference in spin precession, of polarized ultracold neutrons (UCN) produced and stored in a superfluid-helium-filled cell, when the magnetic and electric fields are parallel and antiparallel. A key feature of the experimental method is the use of polarized 3He atoms within the cell acting as both spin analyzer and comagnetometer to the UCN. In one mode of running, the 3He precession signal is detected by SQUID gradiometers adjacent to the cell. This talk will cover recent experimental studies of a prototype SQUID gradiometer suitable for the nEDM experiment. This work was supported by DOE Office Of Science, Nuclear Physics.

  1. {sup 3}He Spin-Dependent Cross Sections and Sum Rules

    SciTech Connect

    Slifer, K.; Auerbach, L.; Choi, Seonho; Incerti, S.; Lakuriqi, E.; Meziani, Z.-E.; Amarian, M.; Ketikyan, A.; Voskanian, H.; Averett, T.; Berthot, J.; Bertin, P.; DiSalvo, R.; Fonvieille, H.; Laveissiere, G.; Roblin, Y.

    2008-07-11

    We present a measurement of the spin-dependent cross sections for the {sup 3}He-vector (e-vector,e{sup '})X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1{<=}Q{sup 2}{<=}0.9 GeV{sup 2}. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.

  2. Heavy-baryon chiral perturbation theory approach to thermal neutron capture on {sup 3}He

    SciTech Connect

    Lazauskas, Rimantas; Park, Tae-Sun

    2011-03-15

    The cross section for radiative thermal neutron capture on {sup 3}He ({sup 3}He+n{yields}{sup 4}He+{gamma}; known as the hen reaction) is calculated based on heavy-baryon chiral perturbation theory. The relevant M1 operators are derived up to next-to-next-to-next-to-leading order (N{sup 3}LO). The initial and final nuclear wave functions are obtained from the rigorous Faddeev-Yakubovski equations for five sets of realistic nuclear interactions. Up to N{sup 3}LO, the M1 operators contain two low-energy constants, which appear as the coefficients of nonderivative two-nucleon contact terms. After determining these two constants using the experimental values of the magnetic moments of the triton and {sup 3}He, we carry out a parameter-free calculation of the hen cross section. The results are in good agreement with the data.

  3. Double spin asymmetries of inclusive hadron electroproduction from a transversely polarized 3He target

    NASA Astrophysics Data System (ADS)

    Zhao, Y. X.; Allada, K.; Aniol, K.; Annand, J. R. M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M.; Deconinck, W.; de Jager, C. W.; De Leo, R.; Deng, X.; Deur, A.; Ding, H.; Dolph, P. A. M.; Dutta, C.; Dutta, D.; El Fassi, L.; Frullani, S.; Gao, H.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Guo, L.; Hamilton, D.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, J.; Huang, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; Katich, J.; Kelleher, A.; Kim, W.; Kolarkar, A.; Korsch, W.; LeRose, J. J.; Li, X.; Li, Y.; Lindgren, R.; Liyanage, N.; Long, E.; Lu, H.-J.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; McNulty, D.; Meziani, Z.-E.; Michaels, R.; Moffit, B.; Muñoz Camacho, C.; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J.-C.; Phillips, S. K.; Posik, M.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Rakhman, A.; Ransome, R.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Širca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, W. A.; Urciuoli, G. M.; Vilardi, I.; Wang, K.; Wojtsekhowski, B.; Wang, Y.; Yan, X.; Yao, H.; Ye, Y.; Ye, Z.; Yuan, L.; Zhan, X.; Zhang, Y.; Zhang, Y.-W.; Zhao, B.; Zheng, X.; Zhu, L.; Zhu, X.; Zong, X.; Jefferson Lab Hall A Collaboration

    2015-07-01

    We report the measurement of beam-target double spin asymmetries (ALT) in the inclusive production of identified hadrons, e ⃗ + 3He↑→h+X, using a longitudinally polarized 5.9-GeV electron beam and a transversely polarized 3He target. Hadrons (π ±,K±, and proton) were detected at 16° with an average momentum =2.35 GeV/c and a transverse momentum (pT) coverage from 0.60 to 0.68 GeV/c. Asymmetries from the 3He target were observed to be nonzero for π± production when the target was polarized transversely in the horizontal plane. The π+ and π- asymmetries have opposite signs, analogous to the behavior of ALT in semi-inclusive deep-inelastic scattering.

  4. Neutron radiography of a static density gradient of 3He gas at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Wichmann, G.; Antognini, A.; Eggenberger, A.; Kirch, K.; Piegsa, F. M.; Soler, U.; Stahn, J.; Taqqu, D.

    2016-04-01

    We demonstrate a stationary helium gas density gradient which is needed for a proposed novel low-energy μ+ beam line. In a closed system with constant pressure the corresponding density gradient is only a function of the temperature. In a neutron radiography experiment two gas cells with different geometries were filled with 3He gas at constant pressures of about 10 mbar. Temperatures in the range from 6 K to 40 K were applied and density distributions with a maximum to minimum density ratio of larger than 3 were realized. The distribution was investigated employing the strongly neutron absorbing isotope 3He. A simple one-dimensional approach derived from Fourier's law describes the obtained gas density with a deviation < 2 %.

  5. Hybrid K-Rb Spin Exchange Optical Pumping Cells for the Polarization of ^3He

    NASA Astrophysics Data System (ADS)

    Couture, Alex; Daniels, Tim; Arnold, Charles; Clegg, Tom

    2006-11-01

    We are transitioning from polarizing ^3He using optical pumping cells charged with pure Rb to using a mixture of Rb and K, lean in Rb. The reason for this is the spin exchange efficiency between K and ^3He is an order of magnitude greater than that of Rb and ^3He. Also the spin exchange cross section between Rb and K is very large, which leads to a very fast rate of polarization transfer from Rb to K. Thus by optically pumping using a standard 795 nm Rb laser on a hybrid K-Rb cell, we can obtain significant improvements in spin-up time as well as improvements in overall polarization.[1] We produce hybrid pumping cells at TUNL using a filling station consisting of an oven and a turbo pumping station to bake out and pump away any impurities in the cells. The alkali metals are introduced into the pumping cells from a Y-shaped manifold with a separate retort for each alkali. We are able to determine the ratio of K to Rb in the vapor using white light absorption spectroscopy. Light from a halogen light bulb is incident upon the heated cell and enters a spectrometer beyond. We examine the relative sizes of the D1 and D2 absorption lines for the two alkali metals. We will have data comparing hybrid cells to pure Rb cells, GE-180 cells to Pyrex, and are working to obtain comparative performance data for spectrally unnarrowed and narrowed lasers. Our latest results will be reported. [1] E. Babcock, et al. (2003) Phys. Rev. Letter Vol. 91, Num.12, 123003

  6. Supersymmetric dark matter search via spin-dependent interaction with 3He

    NASA Astrophysics Data System (ADS)

    Moulin, E.; Mayet, F.; Santos, D.

    2005-05-01

    The potentialities of MIMAC-He3, a MIcro-tpc MAtrix of Chambers of Helium-3, for supersymmetric dark matter search are discussed within the framework of effective MSSM models without gaugino mass unification at the GUT scale. A phenomenological study has been done to investigate the sensitivity of the MIMAC-He3 detector to neutralinos (M≳6GeV/c) via spin-dependent interaction with 3He as well as its complementarity to direct and indirect detection experiments. Comparison with other direct dark matter searches will be presented in a WIMP model-independent framework.

  7. Distorted spin dependent spectral function of {sup 3}He and semi-inclusive deep inelastic scattering processes

    SciTech Connect

    Kaptari, Leonya P.; Del Dotto, Alessio; Pace, Emanuele; Salme, Giovanni; Scopetta, Sergio

    2014-03-01

    The spin dependent spectral function, relevant to describe polarized electron scattering off polarized {sup 3}He, is studied, within the Plane Wave Impulse Approximation and taking into account final state interaction effects (FSI). In particular, the case of semi-inclusive deep inelastic scattering (SiDIS) is considered, evaluating the FSI of the hadronizing quark with the nuclear remnants. It is shown that particular kinematical regions can be selected to minimize the latter effects, so that parton distributions in the neutron can be accessed. On the other side, in the regions where FSI dominates, the considered reactions can elucidate the mechanism of hadronization of quarks during the propagation in the nuclear medium. It is shown that the obtained spin dependent spectral function can be directly applied to investigate the SiDIS reaction e-vector + {sup 3}He-vector to h+X, where the hadron h originates from the current fragmentation. Experiments of this type are being performed at JLab to extract neutron transverse momentum dependent parton distributions. As a case study, a different SiDIS process, with detection of slow (A-1) systems in the final state, is considered in more details, in order to establish when nuclear structure effects and FSI can be distinguished from elementary reactions on quasi-free nucleons. It is argued that, by a proper choice of kinematics, the origin of nuclear effects in polarized DIS phenomena and the details of the interaction between the hadronizing quark and the nuclear medium can be investigated at a level which is not reachable in inclusive deep inelastic scattering.

  8. 3He neutron detector design for active detection of cargo containers

    NASA Astrophysics Data System (ADS)

    McDevitt, Daniel B.; Eberhard, J. W.; Zelakiewicz, Scott; Maschinot, Aaron

    2008-04-01

    We report on the design of a neutron detector using industry standard 3He tubes to count delayed neutrons during the interrogation of cargo containers for the presence of Special Nuclear Material (SNM). Simulations of the detector design were run for delayed neutron spectra for a variety of cargos containing SNM using the Monte Carlo computer code COG. The simulations identified parameters crucial to optimize the detector design. These choices include moderating material type and thickness, tube spacing, tube pressure and number of tubes. An experimental prototype was also constructed based on the simulated design specifications. This paper discusses the parameters that lead up to the optimized detector design. It also compares the performance of the Monte Carlo simulated design and the experimental detector when exposed to a 239Pu-Be source.

  9. A Metastability-Exchange Optical Pumping and Compression System using Polarized 3 He for a Proposed Laboratory Search for Neutron Monopole-Dipole Interactions

    NASA Astrophysics Data System (ADS)

    Smith, Erick; Ariadne Collaboration

    2015-04-01

    3 He nuclei polarized using the metastability-exchange optical pumping (MEOP) method have been used for scientific applications such as magnetometry in space, neutron polarization and analysis, and medical imaging. In this talk we explain how this technique is also well-suited for a proposed experiment to search for possible monopole-dipole interactions of polarized 3 He nuclei with matter. The P-odd and T-odd monopole-dipole potential proposed by Moody and Wilczek is proportional to s-> . r-> where s-> is the 3 He spin and r-> is the separation between the particles. It can be induced by axions, and ARIADNE proposes to perform NMR on a polarized 3 He ensemble at 4K with a radially-slotted tungsten disk spinning at a multiple of the 3 He Larmour frequency to induce a resonant monopole-dipole perturbation. The radial slot length variations are chosen to maximize sensitivity to a monopole-dipole interaction range corresponding to the axion window. We describe the advantages that MEOP presents for this experiment and describe the MEOP-based polarized 3 He gas compression system at Indiana University.

  10. Safety analysis of high pressure 3He-filled micro-channels for thermal neutron detection.

    SciTech Connect

    Ferko, Scott M.; Galambos, Paul C.; Derzon, Mark Steven; Renzi, Ronald F.

    2008-11-01

    This document is a safety analysis of a novel neutron detection technology developed by Sandia National Laboratories. This technology is comprised of devices with tiny channels containing high pressure {sup 3}He. These devices are further integrated into large scale neutron sensors. Modeling and preliminary device testing indicates that the time required to detect the presence of special nuclear materials may be reduced under optimal conditions by several orders of magnitude using this approach. Also, these devices make efficient use of our {sup 3}He supply by making individual devices more efficient and/or extending the our limited {sup 3}He supply. The safety of these high pressure devices has been a primary concern. We address these safety concerns for a flat panel configuration intended for thermal neutron detection. Ballistic impact tests using 3 g projectiles were performed on devices made from FR4, Silicon, and Parmax materials. In addition to impact testing, operational limits were determined by pressurizing the devices either to failure or until they unacceptably leaked. We found that (1) sympathetic or parasitic failure does not occur in pressurized FR4 devices (2) the Si devices exhibited benign brittle failure (sympathetic failure under pressure was not tested) and (3) the Parmax devices failed unacceptably. FR4 devices were filled to pressures up to 4000 + 100 psig, and the impacts were captured using a high speed camera. The brittle Si devices shattered, but were completely contained when wrapped in thin tape, while the ductile FR4 devices deformed only. Even at 4000 psi the energy density of the compressed gas appears to be insignificant compared to the impact caused by the incoming projectile. In conclusion, the current FR4 device design pressurized up to 4000 psi does not show evidence of sympathetic failure, and these devices are intrinsically safe.

  11. Single spin asymmetries of inclusive hadrons produced in electron scattering from a transversely polarized 3He target

    NASA Astrophysics Data System (ADS)

    Allada, K.; Zhao, Y. X.; Aniol, K.; Annand, J. R. M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M.; Deconinck, W.; de Jager, C. W.; De Leo, R.; Deng, X.; Deur, A.; Ding, H.; Dolph, P. A. M.; Dutta, C.; Dutta, D.; Fassi, L. El; Frullani, S.; Gao, H.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Guo, L.; Hamilton, D.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, J.; Huang, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; Katich, J.; Kelleher, A.; Kim, W.; Kolarkar, A.; Korsch, W.; LeRose, J. J.; Li, X.; Li, Y.; Lindgren, R.; Liyanage, N.; Long, E.; Lu, H.-J.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; McNulty, D.; Meziani, Z.-E.; Michaels, R.; Moffit, B.; Camacho, C. Muñoz; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J.-C.; Phillips, S. K.; Posik, M.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Rakhman, A.; Ransome, R.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Širca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, A.; Urciuoli, G. M.; Vilardi, I.; Wang, K.; Wang, Y.; Wojtsekhowski, B.; Yan, X.; Yao, H.; Ye, Y.; Ye, Z.; Yuan, L.; Zhan, X.; Zhang, Y.; Zhang, Y.-W.; Zhao, B.; Zheng, X.; Zhu, L.; Zhu, X.; Zong, X.; Jefferson Lab Hall A Collaboration

    2014-04-01

    We report the first measurement of target single spin asymmetries (AN) in the inclusive hadron production reaction, e +3He↑→h+X, using a transversely polarized 3He target. The experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Three types of hadrons (π±, K±, and proton) were detected in the transverse hadron momentum range 0.54 3He target and extracted for neutrons are opposite in sign with a small increase observed as a function of pT.

  12. Single spin asymmetries of inclusive hadrons produced in electron scattering from a transversely polarized 3 He target

    DOE PAGESBeta

    Allada, K.; Zhao, Y. X.; Aniol, K.; Annand, J. R. M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; et al

    2014-04-07

    We report the first measurement of target single-spin asymmetries (AN) in the inclusive hadron production reaction, e + 3He↑→h+X, using a transversely polarized 3 He target. This experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Three types of hadrons (π±, K± and proton) were detected in the transverse hadron momentum range 0.54 < pT < 0.74 GeV/c. The range of xF for pions was -0.29 < xF< -0.23 and for kaons -0.25 < xF<-0.18. The observed asymmetry strongly depends on the type of hadron. A positive asymmetry is observed for π+ and K+. Amore » negative asymmetry is observed for π–. The magnitudes of the asymmetries follow |Aπ –|<|Aπ +|<|AK +|. The K– and proton asymmetries are consistent with zero within the experimental uncertainties. The π+ and π– asymmetries measured for the 3He target and extracted for neutrons are opposite in sign with a small increase observed as a function of pT.« less

  13. Precision Measurement of the Spin-dependent Asymmetry in the Threshold Region of Quasielastic 3He

    SciTech Connect

    Feng Xiong

    2002-09-01

    The first precision measurement of the spin-dependent asymmetry in the threshold region of polarized {sup 3}He(polarized e, e') was carried out in Hall A at the Jefferson Laboratory, using a longitudinally polarized continuous electron beam incident on a high-pressure polarized {sup 3}He gas target. The polarized electron beam was generated by illuminating a strained GaAs cathode with high intensity circularly polarized laser light, and an average beam polarization of about 70% was achieved. The {sup 3}He target was polarized based on the principle of spin-exchange optical pumpint and the average target polarization was about 30%. The scattered electrons were detected in the two Hall A high resolution spectrometers, HRSe and HRSh. The data from HRSh were used for this analysis and covered both the elastic peak and the threshold region. Two kinematic points were measured in the threshold region, one with a central Q{sup 2}-value of 0.1 (GeV/c){sup 2} at an incident beam energy E{sub 0} = 0.778 GeV and the other with a central Q{sup 2}-value of 0.2 (GeV/c){sup 2} at E-0 = 1.727 GeV. The average beam current was 10 mu-A, which was mainly due to the limitation of the polarized {sup 3}He target. The measured asymmetry was compared with both plane wave impulse approximation (PWIA) calculations and non-relativistic full Faddeev calculations which include both final-state interactions (FSIs) and meson-exchange currents (MECs) effects. The poor description of the data by PWIA calculations at both Q{sup 2}-values suggests the existence of strong FSI and MEC effects in the threshold region of polarized {sup 3}He (polarized e, e'). Indeed, the agreement between the data and full calculations is very good at Q{sup 2} = 0.1 (GeV/c){sup 2}. On the other hand, a small discrepancy at Q{sup 2} = 0.2 (GeV/c){sup 2} is observed, which might be due to some Q{sup 2} -dependent effects such as relativity and three-nucleon forces (3NFs), which are not included in the framework of non

  14. Detecting the Majorana fermion surface state of ^3He-B through spin relaxation

    NASA Astrophysics Data System (ADS)

    Chung, Suk Bum; Zhang, Shoucheng

    2010-03-01

    The concept of the Majorana fermion has been postulated more than eighty years ago; however, this elusive particle has never been observed in nature. The non-local character of the Majorana fermion can be useful for topological quantum computation. Recently, it has been shown that the 3He-B phase is a time-reversal invariant topological superfluid, with a single component of gapless Majorana fermion state localized on the surface. Such a Majorana surface state contains half the degrees of freedom of the single Dirac surface state recently observed in topological insulators. We show here that the Majorana surface state can be detected through an electron spin relaxation experiment. The Majorana nature of the surface state can be revealed though the striking angular dependence of the relaxation time on the magnetic field direction, 1/T1sin^2 θ where θ is the angle between the magnetic field and the surface normal. The temperature dependence of the spin relaxation rate can reveal the gapless linear dispersion of the Majorana surface state. We propose a spin relaxation experiment setup where we inject an electron inside a nano- sized bubble below the helium liquid surface.

  15. A capture-gated neutron calorimeter using plastic scintillators and 3He drift tubes

    SciTech Connect

    Wang, Zhehui; Morris, Christopher L; Spaulding, Randy J; Bacon, Jeffrey D; Borozdin, Konstantin N; Chung, Kiwhan; Clark, Deborah J; Green, Jesse A; Greene, Steven J; Hogan, Gary E; Jason, Andrew; Lisowski, Paul W; Makela, Mark F; Mariam, Fessaha G; Miyadera, Haruo; Murray, Matthew M; Saunders, Alexander; Wysocki, Frederick J; Gray, Frederick E

    2010-01-01

    A segmented neutron calorimeter using nine 4-inch x 4-inch x 48-inch plastic scintillators and sixteen 2-inch-diameter 48-inch-long 200-mbar-{sup 3}He drift tubes is described. The correlated scintillator and neutron-capture events provide a means for n/{gamma} discrimination, critical to the neutron calorimetry when the {gamma} background is substantial and the {gamma} signals are comparable in amplitude to the neutron signals. A single-cell prototype was constructed and tested. It can distinguish between a {sup 17}N source and a {sup 252}Cf source when the {gamma} and the thermal neutron background are sufficiently small. The design and construction of the nine-cell segmented detector assembly follow the same principle. By recording the signals from individual scintillators, additional {gamma}-subtraction schemes, such as through the time-of-flight between two scintillators, may also be used. The variations of the light outputs from different parts of a scintillator bar are less than 10%.

  16. Neutron electric dipole moment and dressed spin

    NASA Astrophysics Data System (ADS)

    Chu, Ping-Han

    The neutron electric dipole moment (EDM) experiment has played a unique role in examining the violation of fundamental symmetries and understanding the nature of electroweak and strong interaction. A non-zero neutron EDM is one of direct evidence for CP and T violation and has the potential to reveal the origin of CP violation and to explore physics beyond the Standard Model. A new neutron EDM experiment will be built to improve a factor of 100 by using a novel technique of ultra-cold neutrons(UCN) in superfluid 4He at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL). In the experiment, 3He in the measurement cell will be used as a neutron spin analyzer and a comagnetometer. The absorption between UCN and 3He atoms will emit scintillation light in the superfluid 4He depending on the angle between nuclear spins of two particles. Consequently, the neutron precession frequency can be derived by the scintillation light amplitude. Furthermore, the 3He precession frequency can be measured by the superconducting quantum interference device (SQUID). A dressed-spin technique will also be applied to measure the small precession frequency change due to a non-zero neutron EDM. The dressed-spin technique is used to modify the effective precession frequencies of neutrons and 3He atoms to make them equal by applying an oscillatory field (dressing field) that is perpendicular to the static magnetic field. The phenomenon of the dressed spin for 3He in a cell should be demonstrated before the proposed neutron EDM experiment. A successful measurement over a broad range of the amplitude and frequency of the dressing field was done at the University of Illinois. The observed effects can be explained by using quantum optics formalism. The formalism is diagonalized to solve the solution and confirms the data. In addition, the application of the dressed-spin technique was investigated. The modulation and the feedback loop technique should be considered with

  17. Measurement of the Target-Normal Single-Spin Asymmetry in Quasielastic Scattering from the Reaction (3)He(↑)(e,e').

    PubMed

    Zhang, Y-W; Long, E; Mihovilovič, M; Jin, G; Allada, K; Anderson, B; Annand, J R M; Averett, T; Ayerbe-Gayoso, C; Boeglin, W; Bradshaw, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J P; Chudakov, E; De Leo, R; Deng, X; Deur, A; Dutta, C; El Fassi, L; Flay, D; Frullani, S; Garibaldi, F; Gao, H; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Gomez, J; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, J; Ibrahim, H; de Jager, C W; Jensen, E; Jiang, X; St John, J; Jones, M; Kang, H; Katich, J; Khanal, H P; King, P; Korsch, W; LeRose, J; Lindgren, R; Lu, H-J; Luo, W; Markowitz, P; Meziane, M; Michaels, R; Moffit, B; Monaghan, P; Muangma, N; Nanda, S; Norum, B E; Pan, K; Parno, D; Piasetzky, E; Posik, M; Punjabi, V; Puckett, A J R; Qian, X; Qiang, Y; Qiu, X; Riordan, S; Ron, G; Saha, A; Sawatzky, B; Schiavilla, R; Schoenrock, B; Shabestari, M; Shahinyan, A; Širca, S; Subedi, R; Sulkosky, V; Tobias, W A; Tireman, W; Urciuoli, G M; Wang, D; Wang, K; Wang, Y; Watson, J; Wojtsekhowski, B; Ye, Z; Zhan, X; Zhang, Y; Zheng, X; Zhao, B; Zhu, L

    2015-10-23

    We report the first measurement of the target single-spin asymmetry, A(y), in quasielastic scattering from the inclusive reaction (3)He(↑)(e,e') on a (3)He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A(y) can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q(2)=0.13, 0.46, and 0.97  GeV(2). These measurements demonstrate, for the first time, that the (3)He asymmetry is clearly nonzero and negative at the 4σ-9σ level. Using measured proton-to-(3)He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q(2) is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q(2)=0.97  GeV(2) agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions. PMID:26551107

  18. Measurement of the Target-Normal Single-Spin Asymmetry in Quasielastic Scattering from the Reaction 3He ↑(e ,e' )

    NASA Astrophysics Data System (ADS)

    Zhang, Y.-W.; Long, E.; Mihovilovič, M.; Jin, G.; Allada, K.; Anderson, B.; Annand, J. R. M.; Averett, T.; Ayerbe-Gayoso, C.; Boeglin, W.; Bradshaw, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J. P.; Chudakov, E.; De Leo, R.; Deng, X.; Deur, A.; Dutta, C.; El Fassi, L.; Flay, D.; Frullani, S.; Garibaldi, F.; Gao, H.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Gomez, J.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, J.; Ibrahim, H.; de Jager, C. W.; Jensen, E.; Jiang, X.; John, J. St.; Jones, M.; Kang, H.; Katich, J.; Khanal, H. P.; King, P.; Korsch, W.; LeRose, J.; Lindgren, R.; Lu, H.-J.; Luo, W.; Markowitz, P.; Meziane, M.; Michaels, R.; Moffit, B.; Monaghan, P.; Muangma, N.; Nanda, S.; Norum, B. E.; Pan, K.; Parno, D.; Piasetzky, E.; Posik, M.; Punjabi, V.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Qiu, X.; Riordan, S.; Ron, G.; Saha, A.; Sawatzky, B.; Schiavilla, R.; Schoenrock, B.; Shabestari, M.; Shahinyan, A.; Širca, S.; Subedi, R.; Sulkosky, V.; Tobias, W. A.; Tireman, W.; Urciuoli, G. M.; Wang, D.; Wang, K.; Wang, Y.; Watson, J.; Wojtsekhowski, B.; Ye, Z.; Zhan, X.; Zhang, Y.; Zheng, X.; Zhao, B.; Zhu, L.; Jefferson Lab Hall A Collaboration

    2015-10-01

    We report the first measurement of the target single-spin asymmetry, Ay, in quasielastic scattering from the inclusive reaction 3He ↑(e ,e' ) on a 3He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero Ay can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q2=0.13 , 0.46, and 0.97 GeV2 . These measurements demonstrate, for the first time, that the 3He asymmetry is clearly nonzero and negative at the 4 σ - 9 σ level. Using measured proton-to-3He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1 - 3 )% were obtained. The neutron asymmetry at high Q2 is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q2=0.97 GeV2 agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions.

  19. Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4

    PubMed

    Huang, J; Allada, K; Dutta, C; Katich, J; Qian, X; Wang, Y; Zhang, Y; Aniol, K; Annand, J R M; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J-P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P A M; Dutta, D; El Fassi, L; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; Lerose, J J; Li, X; Li, Y; Lindgren, R; Liyanage, N; Long, E; Lu, H-J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z-E; Michaels, R; Moffit, B; Muñoz Camacho, C; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J C; Phillips, S K; Posik, M; Puckett, A J R; Qiang, Y; Rakhman, A; Ransome, R D; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Sirca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L-G; Tobias, A; Urciuoli, G M; Vilardi, I; Wang, K; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y-W; Zhao, B; Zheng, X; Zhu, L; Zhu, X; Zong, X

    2012-02-01

    We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16neutron A{LT} asymmetries were extracted from the measured {3}He asymmetries and proton over {3}He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g{1T}{q} and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π{-} production on {3}He and the neutron, while our π{+} asymmetries are consistent with zero. PMID:22400926

  20. Measurement of the sup 3 He( n ,. gamma. ) sup 4 He cross section at thermal neutron energies

    SciTech Connect

    Wolfs, F.L.H.; Freedman, S.J.; Nelson, J.E. ); Dewey, M.S.; Greene, G.L. )

    1989-12-18

    We have measured the cross section for radiative capture of thermal neutrons on {sup 3}He. The measured cross section of 54{plus minus}6 {mu}b is used to estimate the astrophysical {ital S} factor for the reaction {sup 3}He({ital p},{ital e}{sup +}{nu}){sup 4}He which gives rise to high-energy neutrinos from the Sun.

  1. Meaurement of the target single-spin asymmetry in quasi-elastic region from the reaction {sup 3}He{up_arrow}(e,e')

    SciTech Connect

    Zhang, Yawei

    2013-10-01

    A measurement of the inclusive target single-spin asymmetry has been performed using the quasi-elastic {sup 3}He{up_arrow}(e,e') reaction with a vertically polarized {sup 3}He target at Q{sup 2} values of 0.13, 0.46 and 0.97 GeV{sup 2}. This asymmetry vanishes under the one photon exchange assumption. But the interference between two-photon exchange and one-photon exchange gives rise to an imaginary amplitude, so that a non-zero A{sub y} is allowed. The experiment, conducted in Hall A of Jefferson Laboratory in 2009, used two independent spectrometers to simultaneously measure the target single-spin asymmetry. Using the effective polarization approximation, the neutron single-spin asymmetries were extracted from the measured {sup 3}He asymmetries. The measurement is to establish a non-vanishing A{sub y}. Non-zero asymmetries were observed at all Q{sup 2} points, and the overall precision is an order of magnitude improved over the existing proton data. The data provide new constraints on Generalized Parton Distribution (GPD) models and new information on the dynamics of the two-photon exchange process.

  2. Measurement of the Target-Normal Single-Spin Asymmetry in Deep-Inelastic Scattering from the Reaction 3He{uparrow}(e,e')X

    SciTech Connect

    Katich, Joseph; Qian, Xin; Zhao, Yuxiang; Allada, Kalyan; Aniol, Konrad; Annand, John; Averett, Todd; Benmokhtar, Fatiha; Bertozzi, William; Bradshaw, Elliott; Bosted, Peter; Camsonne, Alexandre; Canan, Mustafa; Cates, Gordon; Chen, Chunhua; Chen, Jian-Ping; Chen, Wei; Chirapatpimol, Khem; Chudakov, Eugene; Cisbani, Evaristo; Cornejo, Juan; Cusanno, Francesco; Dalton, Mark; Deconinck, Wouter; De Jager, Cornelis; De Leo, Raffaele; Deng, Xiaoyan; Deur, Alexandre; Ding, Huaibo; Dolph, Peter; Dutta, Chiranjib; Dutta, Dipangkar; El Fassi, Lamiaa; Frullani, Salvatore; Gao, Haiyan; Garibaldi, Franco; Gaskell, David; Gilad, Gilad; Gilman, Ronald; Glamazdin, Oleksandr; Golge, Serkan; Guo, Lei; Hamilton, David; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Huang, Jijun; Huang, Min; Ibrahim Abdalla, Hassan; Iodice, Mauro; Jin, Ge; Jones, Mark; Kelleher, Aidan; Kim, Wooyoung; Kolarkar, Ameya; Korsch, Wolfgang; LeRose, John; Li, Xiaomei; Li, Y; Lindgren, Richard; Liyanage, Nilanga; Long, Elena; Lu, Hai-jiang; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; McNulty, Dustin; Meziani, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Munoz Camacho, Carlos; Nanda, Sirish; Narayan, Amrendra; Nelyubin, Vladimir; Norum, Blaine; Oh, Yoomin; Osipenko, Mikhail; Parno, Diana; Peng, Jen-chieh; Phillips, Sarah; Posik, Matthew; Puckett, Andrew; Qiang, Yi; Rakhman, Abdurahim; Ransome, Ronald; Riordan, Seamus; Saha, Arunava; Sawatzky, Bradley; Schulte, Elaine; Shahinyan, Albert; Hashemi Shabestari, Mitra; Sirca, Simon; Stepanyan, Stepan; Subedi, Ramesh; Sulkosky, Vincent; Tang, Liguang; Tobias, William; Urciuoli, Guido; Vilardi, Ignazio; Wang, Kebin; Wang, Y; Wojtsekhowski, Bogdan; Yan, X; Yao, Huan; Ye, Yunxiu; Ye, Z; Yuan, Lulin; Zhan, Xiaohui; Zhang, Yi; Zhang, Y -W; Zhao, Bo; Zheng, Xiaochao; Zhu, Lingyan; Zhu, Xiaofeng; Zong, Xing

    2014-07-01

    We report the first measurement of the target single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3He{uparrow}(e,e')X on a 3He gas target polarized normal to the lepton plane. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-3He cross section ratios. The measured neutron asymmetries are negative with an average value of (−1.04+/-0.38)×10−2 for invariant mass W>2 GeV, which is non-zero at the 2.75sigma level. Theoretical calculations, which assume two-photon exchange with quasi-free quarks, predict a neutron asymmetry of O(10−4) when both photons couple to one quark, and O(10−2) for the photons coupling to different quarks. Our measured asymmetry agrees both in sign and magnitude with the prediction that uses input based on the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.

  3. Empirical formula on (n,(3)He) reaction cross sections at 14.6MeV neutrons.

    PubMed

    Yiğit, Mustafa

    2015-11-01

    The systematic behavior of the cross sections of (n,(3)He) nuclear reactions has been studied by various researches at neutron energy of 14.6MeV. A new empirical formula based on the Q-value dependence of the cross sections of the investigated reaction has been proposed. The cross sections obtained from the new formula are compared with the other proposed formulae results and the experimental data. It seems that the present formula based on the Q-value dependence provides the good description for cross sections of neutron-induced (n,(3)He) nuclear reactions at 14.6MeV. PMID:26218596

  4. Spin assignments to excited states in 22Na through a 24Mg(p,3He)22Na reaction measurement

    SciTech Connect

    Chae, K. Y.; Bardayan, Daniel W; Blackmon, Jeff C; Chipps, K.; Hatarik, Robert; Jones, K. L.; Kozub, R. L.; Liang, J Felix; Matei, Catalin; Moazen, Brian; Nesaraja, Caroline D; O'Malley, Patrick; Pain, S. D.; Pittman, S. T.; Smith, Michael Scott

    2010-10-01

    The level structure of 22Na has been studied at the Holifield Radioactive Ion Beam Facility in Oak Ridge National Laboratory using the 24Mg(p,3He)22Na reaction. 41 and 41.5 MeV proton beams were generated by 25 MV tandem accelerator and bombarded isotopically enriched 24Mg targets. Angular distributions of recoiling 3He particles were extracted by using a segmented annular silicon strip detector array. Spins and parities for ten levels were constrained through a distorted wave Born approximation analysis of angular distributions including three above the proton threshold at 6.739 MeV.

  5. Theoretical Analysis of Neutron and X-ray Scattering Data on 3He

    NASA Astrophysics Data System (ADS)

    Krotscheck, E.; Panholzer, M.

    2011-04-01

    X-ray scattering experiments on bulk liquid 3He (Albergamo et al. in Phys. Rev. Lett. 99:205301, 2007; Schmets and Montfrooij in Phys. Rev. Lett. 100:239601, 2008; Albergamo et al. in Phys. Rev. Lett. 100:239602, 2008) have indicated the possibility of the existence of a sharp collective mode at large momentum transfers. We address this issue within a manifestly microscopic theory of excitations in a Fermi fluid that can be understood as proper generalization of the time-honored theory of Jackson, Feenberg, and Campbell (Jackson in Phys. Rev. A 8:1529, 1973; Feenberg in Theory of Quantum Fluids, 1969; Chang and Campbell in Phys. Rev. B 13:3779, 1976) of excitations in 4He. We show that both neutron and X-ray data can be well explained within a theory where the high momentum excitations lie in fact inside the particle-hole continuum. "Pair fluctuations" contribute a sharpening of the mode compared to the random phase approximation (RPA). When the theoretical results are convoluted with the experimental resolution, the agreement between theory and X-ray data is quite good.

  6. Relaxation time of 3He

    NASA Astrophysics Data System (ADS)

    Gao, Hayian

    2004-10-01

    The next generation of searches for the neutron electric dipole moment using ultra cold neutrons will use polarized ^3He as a co-magnetometer. The first such experiment has been proposed, with a goal of improving the current limit on the neutron EDM by two orders of magnitude. This experiment requires a systematic study of the properties of polarized ^3He at cryogenic temperatures under actual experimental conditions. These experimental conditions include polarized ^3He mixed in a bath of superfluid ^4He in low magnetic field and held in an acrylic cell which is coated with deuterated TetraphenylButadiene . Parts of these systematic studies will be done at Duke University using a newly built, novel refillable double cell ^3 He polarizer based on spin exchange optical pumping with Rubidium vapor. The polarimetry for this apparatus is done with a NMR polarimeter using the adiabatic fast passage method. An alternate polarimeter using free induction decay method is also being built. This apparatus is being used to study the relaxation time and other critical properties of polarized ^3He at temperatures ranging from 2.3 - 4.2 K, under simulated experimental conditions. We will present details about this novel polarizer and show preliminary results of our measurements.

  7. Measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the reaction (3)He(↑)(e,e')X.

    PubMed

    Katich, J; Qian, X; Zhao, Y X; Allada, K; Aniol, K; Annand, J R M; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J-P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P A M; Dutta, C; Dutta, D; El Fassi, L; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, J; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; LeRose, J J; Li, X; Li, Y; Lindgren, R; Liyanage, N; Long, E; Lu, H-J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z-E; Michaels, R; Moffit, B; Muñoz Camacho, C; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J C; Phillips, S K; Posik, M; Puckett, A J R; Qiang, Y; Rakhman, A; Ransome, R D; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Širca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L-G; Tobias, A; Urciuoli, G M; Vilardi, I; Wang, K; Wang, Y; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y; Zhang, Y-W; Zhao, B; Zheng, X; Zhu, L; Zhu, X; Zong, X

    2014-07-11

    We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3)He(↑)(e,e')X on a polarized (3)He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-(3)He cross-section ratios. The measured neutron asymmetries are negative with an average value of (-1.09±0.38)×10(-2) for invariant mass W>2  GeV, which is nonzero at the 2.89σ level. Our measured asymmetry agrees both in sign and magnitude with a two-photon-exchange model prediction that uses input from the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering. PMID:25062169

  8. Investigation and optimisation of mobile NaI(Tl) and 3He-based neutron detectors for finding point sources

    NASA Astrophysics Data System (ADS)

    Nilsson, Jonas M. C.; Finck, Robert R.; Rääf, Christopher

    2015-06-01

    Neutron radiation produces high-energy gamma radiation through (n,γ) reactions in matter. This can be used to detect neutron sources indirectly using gamma spectrometers. The sensitivity of a gamma spectrometer to neutrons can be amplified by surrounding it with polyvinyl chloride (PVC). The hydrogen in the PVC acts as a moderator and the chlorine emits prompt gammas when a neutron is captured. A 4.7-l 3He-based mobile neutron detector was compared to a 4-l NaI(Tl)-detector covered with PVC using this principle. Methods were also developed to optimise the measurement parameters of the systems. The detector systems were compared with regard to their ability to find 241AmBe, 252Cf and 238Pu-13C neutron sources. Results from stationary measurements were used to calculate optimal integration times as well as minimum detectable neutron emission rates. It was found that the 3He-based detector was more sensitive to 252Cf sources whereas the NaI(Tl) detector was more sensitive to 241AmBe and 238Pu-13C sources. The results also indicated that the sensitivity of the detectors to sources at known distances could theoretically be improved by 60% by changing from fixed integration times to list mode in mobile surveys.

  9. Single Spin Asymmetries in Charged Pion Production from Semi-Inclusive Deep Inelastic Scattering on a Transversely Polarized $^3$He Target

    SciTech Connect

    Qian, X; Allada, K; Huang, J; Katich, J; Wang, Y; Zhang, Y; Aniol, K; Annand, J.R.M.; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J -P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P.A.M.; Dutta, D; El Fassi, L; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; LeRose, J J; Li, X; Li, Y; Lindgren, R; Liyanage, N; Long, E; Lu, H -J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z -E; Michaels, R; Moffit, B; Munoz Camacho, C; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J C; Phillips, S K; Posik, M; Puckett, A.J.R.; Qiang, Y; Rakhman, A; Ransome, R D; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Sirca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L -G; Tobias, A; Urciuoli, G M; Vilardi, I; Wang, K; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y -W; Zhao, B; Zheng, X; Zhu, L; Zhu, X; Zong, X

    2011-08-01

    We report the first measurement of target single spin asymmetries in the semi-inclusive $^3{He}(e,e'\\pi^\\pm)X$ reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.14 $< x <$ 0.34 with 1.3 $3$He are consistent with zero, except for the $\\pi^+$ moment at $x=0.34$, which deviates from zero by 2.3$\\sigma$. While the $\\pi^-$ Sivers moments are consistent with zero, the $\\pi^+$ Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and the measured cross section ratio of proton to $^3$He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.

  10. Design and development of a 3He replacement safeguards neutron counter based on 10B-lined proportional detector technology

    SciTech Connect

    Henzlova, Daniela; Evans, Louise; Menlove, Howard O.; Swinhoe, Martyn T.; Rael, Carlos D.; Martinez, Isaac P.; Marlow, Johnna B.

    2012-07-16

    This presentation represents an overview of the experimental evaluation of a boron-lined proportional technology performed within an NA-241 sponsored project on testing of boron-lined proportional counters for the purpose of replacement of {sup 3}He technologies. The presented boron-lined technology will be utilized in a design of a full scale safeguards neutron coincidence counter. The design considerations and the Monte Carlo performance predictions for the counter are also presented.

  11. Neutron spin structure results from JLab Hall A

    SciTech Connect

    Zein-Eddine Meziani

    2004-02-01

    My presentation will focus on some of the latest results of the neutron spin physics program at Jefferson Laboratory in Hall A using a polarized 3He target. This program includes several completed experiments in which the spin structure functions of 3He were measured. The covered kinematic regions were these measurements were performed include the low Q2 resonance and inelastic regions and the high Q2 deep inelastic region. These experiments offer a ground for testing our understanding of the strong regime of quantum chromodynamics (QCD) through the determination of the neutron spin-dependent structure functions and their moments.

  12. Recent Advances of Polarized 3He Target at Jefferson Lab

    SciTech Connect

    Yi Qiang

    2011-10-01

    Polarized {sup 3}He target has been widely used in nuclear and particle experiments to study the neutron structure in the spin degree of freedom, as most of the {sup 3}He spin is carried by the unpaired neutron. Spin-Exchange Optical Pumping (SEOP) process is used in Jefferson Lab Hall A to polarize its {sup 3}He target. Through developments in recent years, both the performance and corresponding polarimetry of such a target were greatly improved. Several experiments recently carried out in Hall A benefited remarkably from this target for the record highest figure of merit.

  13. Calibration experiments of 3He neutron detectors for analyzing neutron emissivity in the hot-ion mode on the GAMMA 10 tandem mirror

    NASA Astrophysics Data System (ADS)

    Kohagura, J.; Cho, T.; Hirata, M.; Watanabe, H.; Minami, R.; Numakura, T.; Yoshida, M.; Ito, H.; Tatematsu, Y.; Yatsu, K.; Miyoshi, S.; Ogura, K.; Kondoh, T.; Nishitani, T.; Kwon, M.; England, A. C.

    2003-03-01

    Under the international fusion cooperating research, 3He neutron detectors in the GAMMA 10 tandem mirror are calibrated by the use of a 252Cf spontaneous fission neutron source (8.96×104 n/s). The calibration experiments are carried out with a "rail system" placed along the magnetic axis of the GAMMA 10 central-cell region, where hot ions in the plasma experiments with the bulk temperatures of ˜10 keV are produced. As compared to a previous neutron monitoring system with a BF3 detector in GAMMA 10, the present 3He systems are designed with about two orders-of-magnitude higher neutron-counting efficiency for analyzing a neutron emissivity from the plasmas in a single plasma discharge alone. Two 3He systems are installed near the middle and the end of the central cell so as to identify the central-cell hot-ion axial profile. The filling pressure of 3He, the effective length, and the diameter of the detector are designed as 5 bar, 300 mm, and 50 mm, respectively. The detector output spectra are carefully analyzed by the use of a preamplifier, a shaping amplifier, as well as a multichannel analyzer for each 3He detector. In the present article, the neutron-counting data from the two 3He detectors due to the on-axis 252Cf scan are interpreted in terms of the d-2 intensity dependence (d being the distance between the detector and the neutron source) as well as the effects of the central-cell magnetic coils and the other machine structural components.

  14. Precision Measurement of the Spin Dependent Asymmetry in the Threshold Region of {sup 3}He(e,e{prime})

    SciTech Connect

    F. Xiong; Dipangkar Dutta; W. Xu; Bryon Anderson; L. Auberbach; Todd Averett; William Bertozzi; Timothy Black; John Calarco; Larry Cardman; Gorden Cates; Zhengwei Chai; Jian-ping Chen; Seonho Choi; Eugene Chudakov; Steve Churchwell; G.S. Corrado; C. Crawford; Dan Dale; Alexandre Deur; Pibaro Djawotho; Bradley Filippone; Mike Finn; Haiyan Gao; Ron Gilman; Alexander Glamazdin; Charles Glashausser; W. Glockle; J. Golak; Javier Gomez; Victor Gorbenko; Jens-Ole Hansen; F. William Hersman; Douglas W. Higinbotham; Richard Holmes; C.R. Howell; E. Hughes; B. Humensky; Sebastian Incerti; Kees de Jager; J.Steffen Jensen; Xiangdong Jiang; C.E. Jones; Mark Jones; R. Kahl; H. Kamada; A. Kievsky; Ioannis Kominis; Wolfgang Korsch; Kevin Kramer; Gerfried Kumbartzki; Michael Kuss; E. Lakuriqi; Meme Liang; Nilanga Liyanage; John LeRose; Sergey Malov; Dimitri Margaziotis; Jeffrey Martin; Kathy McCormick; Robert McKeown; K. McIlhany; Zein-Eddine Meziani; Robert Michaels; G.W. Miller; E. Pace; T. Pavlin; Gerassimos G. Petratos; R.I. Pomatsalyuk; D. Pripstein; David Prout; Ronald Ransome; Yves Roblin; Marat Rvachev; Arun Saha; G. Salme; M. Schnee; Taeksu Shin; Karl Slifer; Paul Souder; Steffen Strauch; Riad Suleiman; M. Sutter; Bryan Tipton; Luminita Todor; M. Viviani; B. Vlahovic; J. Watson; C.F. Williamson; H. Witala; Bogdan B. Wojtsekhowski; J. Yeh; P. Zolnierczuk

    2001-12-10

    We present the first precision measurement of the spin-dependent asymmetry in the threshold region of {sup 3}He(e,e{prime}) at Q{sup 2}-values of 0.1 and 0.2 (GeV/c){sup 2}. The agreement between the data and non-relativistic Faddeev calculations which include both final-state interactions (FSI) and meson-exchange currents (MEC) effects is very good at Q{sup 2} = 0.1 (GeV/c){sup 2}, while a small discrepancy at Q{sup 2} = 0.2 (GeV/c){sup 2} is observed.

  15. The Q^2 Evolution of the GDH sum Rule (on 3He and the Neutron)

    SciTech Connect

    Gordon Cates

    2002-06-01

    We discuss the extention of the Gerasimov-Drell-Hearn (GDH) sum rule, which pertains to real photons, to include scattering due to virtual photons. We present data from Jefferson Laboratory experiment E94-010 which measured the inclusive scattering of polarized electrons from a polarized 3He target over the quasielastic and resonance regions. From these data we exctract the transverse-transverse interference cross section {sigma}{prime}_TT', and compute the Q^2 depenent extended GDH integral.

  16. Neutron phase spin echo

    NASA Astrophysics Data System (ADS)

    Piegsa, Florian M.; Hautle, Patrick; Schanzer, Christian

    2016-04-01

    A novel neutron spin resonance technique is presented based on the well-known neutron spin echo method. In a first proof-of-principle measurement using a monochromatic neutron beam, it is demonstrated that relative velocity changes of down to a precision of 4 ×10-7 can be resolved, corresponding to an energy resolution of better than 3 neV. Currently, the sensitivity is only limited by counting statistics and not by systematic effects. An improvement by another two orders of magnitude can be achieved with a dedicated setup, allowing energy resolutions in the 10 peV regime. The new technique is ideally suited for investigations in the field of precision fundamental neutron physics, but will also be beneficial in scattering applications.

  17. A new 3He-free thermal neutrons detector concept based on the GEM technology

    NASA Astrophysics Data System (ADS)

    Pietropaolo, A.; Murtas, F.; Claps, G.; Quintieri, L.; Raspino, D.; Celentano, G.; Vannozzi, A.; Frasciello, O.

    2013-11-01

    A thermal neutron detector based on the Gas Electron Multiplier technology is presented. It is configured to let a neutron beam interact with a series of borated glass layers placed in sequence along the neutron path inside the device. The detector has been tested on beam both at the ISIS (UK) spallation neutron source and at the TRIGA reactor of ENEA, at the Casaccia Research Center, near Rome in Italy. For a complete characterization and description of the physical mechanism underlying the detector operation, several Monte Carlo simulations were performed using both Fluka and Geant4 code. These simulations are intended to help in seeking the optimal geometrical set-up and material thickness (converter layer, gas gap, sheet substrate) to improve the final detector design in terms of achieving the best detector efficiency possible.

  18. {sup 3}He alternative technologies: 1. Application of neutron image plate detector for powder diffractometry

    SciTech Connect

    Shaikh, A. M.; Krishna, P. S. R.; Shinde, A. B.

    2012-06-05

    Neutron image plate was used for recording powder diffraction pattern from a polycrystalline Fe rod, mounted on the High Q Diffractometer at Dhruva reactor and using neutron beam of {lambda}= 0.783 A and {Phi}= 3 x 10{sup 5} n/cm{sup 2}/sec. The Bragg peaks were sharp and well resolved. The overall resolution ({Delta}2{theta}/2{theta}) value was found be {approx}0.025.

  19. 3He alternative technologies: 1. Application of neutron image plate detector for powder diffractometry

    NASA Astrophysics Data System (ADS)

    Shaikh, A. M.; Krishna, P. S. R.; Shinde, A. B.

    2012-06-01

    Neutron image plate was used for recording powder diffraction pattern from a polycrystalline Fe rod, mounted on the High Q Diffractometer at Dhruva reactor and using neutron beam of λ = 0.783 Å and Φ = 3 × 105 n/cm2/sec. The Bragg peaks were sharp and well resolved. The overall resolution (Δ2θ/2θ) value was found be ˜0.025.

  20. Vortices in rotating superfluid 3He.

    PubMed

    Lounasmaa, O V; Thuneberg, E

    1999-07-01

    In this review we first present an introduction to 3He and to the ROTA collaboration under which most of the knowledge on vortices in superfluid 3He has been obtained. In the physics part, we start from the exceptional properties of helium at millikelvin temperatures. The dilemma of rotating superfluids is presented. In 4He and in 3He-B the problem is solved by nucleating an array of singular vortex lines. Their experimental detection in 3He by NMR is described next. The vortex cores in 3He-B have two different structures, both of which have spontaneously broken symmetry. A spin-mass vortex has been identified as well. This object is characterized by a flow of spins around the vortex line, in addition to the usual mass current. A great variety of vortices exist in the A phase of 3He; they are either singular or continuous, and their structure can be a line or a sheet or fill the whole liquid. Altogether seven different types of vortices have been detected in 3He by NMR. We also describe briefly other experimental methods that have been used by ROTA scientists in studying vortices in 3He and some important results thus obtained. Finally, we discuss the possible applications of experiments and theory of 3He to particle physics and cosmology. In particular, we report on experiments where superfluid 3He-B was heated locally by absorption of single neutrons. The resulting events can be used to test theoretical models of the Big Bang at the beginning of our universe. PMID:10393895

  1. Vortices in rotating superfluid 3He

    PubMed Central

    Lounasmaa, Olli V.; Thuneberg, Erkki

    1999-01-01

    In this review we first present an introduction to 3He and to the ROTA collaboration under which most of the knowledge on vortices in superfluid 3He has been obtained. In the physics part, we start from the exceptional properties of helium at millikelvin temperatures. The dilemma of rotating superfluids is presented. In 4He and in 3He-B the problem is solved by nucleating an array of singular vortex lines. Their experimental detection in 3He by NMR is described next. The vortex cores in 3He-B have two different structures, both of which have spontaneously broken symmetry. A spin-mass vortex has been identified as well. This object is characterized by a flow of spins around the vortex line, in addition to the usual mass current. A great variety of vortices exist in the A phase of 3He; they are either singular or continuous, and their structure can be a line or a sheet or fill the whole liquid. Altogether seven different types of vortices have been detected in 3He by NMR. We also describe briefly other experimental methods that have been used by ROTA scientists in studying vortices in 3He and some important results thus obtained. Finally, we discuss the possible applications of experiments and theory of 3He to particle physics and cosmology. In particular, we report on experiments where superfluid 3He-B was heated locally by absorption of single neutrons. The resulting events can be used to test theoretical models of the Big Bang at the beginning of our universe. PMID:10393895

  2. Online SEOP polarization of Large Area Neutron Spin Filters

    NASA Astrophysics Data System (ADS)

    Babcock, Earl; Salhi, Zahir; Ioffe, Alexander

    2015-04-01

    The Juelich Center for neutron Science has a program to use SEOP polarized 3He Neutron Spin Filters (3He NSF) on many neutron scattering instruments. The main applications are for polarization analysis of the scattered beam. As such, the devices must operate in close proximity to the neutron sample and sample environment which can include complicated cryostats, humidity and pressure cells, and high field magnets. Thus we have developed novel magnetic cavities to house the 3He NSF cells which allow for simultaneous optical pumping on the instruments. Further we continually develop and redevelop the laser sources which must be relatively narrow band and have long term (i.e. months) stability and robust operation. The first fully operational polarizer has been used continuously for over 2, 60-day reactor cycles at the FRM2. This device uses a 12.5 cm I.D. 3He cell, and has a 3He storage lifetime, including the cells lifetime, in excess of 200 hours with the cell about 60 cm from the sample position inside a 1.2 T electromagnet, and has achieved over 75% 3He polarisation when fully optimized. This talk will describe the magnetic cavities, and laser sources as well as provide a description of the completed 3He polarizer devices.

  3. Analysis of ultratrace lithium and boron by neutron activation and mass-spectrometric measurement of 3He and 4He.

    PubMed

    Clarke, W B; Koekebakker, M; Barr, R D; Downing, R G; Fleming, R F

    1987-01-01

    A new technique for analysis of lithium and boron at ultratrace concentrations (less than 10(-8)g g-1) is described. The method consists of mass-spectrometric assay of 3He from decay of tritium produced by thermal-neutron reaction on 6Li, and 4He produced by thermal-neutron reaction on 10B. Two neutron-irradiation facilities were used: the McMaster reactor, which is 235U-enriched and light-water moderated; and a graphite-moderated thermal column attached to the 235U-enriched, heavy-water-moderated core at the National Bureau of Standards (NBS) reactor. In the McMaster irradiations, fast neutrons (greater than 0.2 MeV) induce the reactions 14N(n, 3H)12C, 12C(n, alpha)9Be, 16O(n, alpha)13C, and 14N(n, alpha)11B. These reactions become serious sources of error in samples such as human blood which have very low concentrations of lithium and boron, and high concentrations of nitrogen, carbon and oxygen. In the NBS thermal column, fast-neutron reactions are virtually absent, and only corrections for thermal-neutron capture by deuterium, and thermal-neutron (n, alpha) reactions on oxygen, sulfur, chlorine, potassium, and calcium need to be taken into account. Results are presented for various actual samples including human blood and its components, and some standard biological reference materials, to provide a realistic base for other workers to judge the reliability of the method. PMID:2822629

  4. Non-spin-flip ( 3He, t) charge-exchange and isobaric analog states of actinide nuclei studied at θ = 0°, E( 3He) = 76 MeV and 200 MeV

    NASA Astrophysics Data System (ADS)

    Jänecke, J.; Becchetti, F. D.; van den Berg, A. M.; Berg, G. P. A.; Brouwer, G.; Greenfield, M. B.; Harakeh, M. N.; Hofstee, M. A.; Nadasen, A.; Roberts, D. A.; Sawafta, R.; Schippers, J. M.; Stephenson, E. J.; Stewart, D. P.; van der Werf, S. Y.

    1991-04-01

    The ( 3He, t) charge-exchange reaction has been studied at θ = 0° and bombarding energies of E( 3He) = 76.5 MeV and 200 MeV. Spectra were measured using magnetic analysis for target nuclei of 12, 13C, 16O, 19F, 28, 29, 30Si, 90Zr, 117, 120Sn, natTa, natW, 197Au, 208Pb, 230, 232Th, 234, 236, 238U and 244Pu. The measurements at 76.5 MeV concentrated on the isobaric analog states of several actinide nuclei, particularly on their widths and the branching ratios for proton decay. Cross sections, Q-values and total widths were determined for the transitions to the isobaric analog states. Coulomb displacement energies derived from the measured Q-values display the influence of deformed nuclear shapes. Escape widths Γ ↑ and spreading widths Γ ↓ of the isobaric analog states in five actinide nuclei were deduced from the measured proton-decay branching ratios. They were found to be in agreement with predictions which postulate isospin mixing via the Coulomb force with the ( T0-1)-component of the isovector giant monopole resonance. The measurements at 200 MeV were concerned with transitions to isobaric analog states in both light and heavy nuclei, including several actinide nuclei, but Gamow-Teller resonances and transitions to numerous other states were also observed. The measured cross sections for several transitions to isobaric analog states from 30Si to 208Pb were used to extract the effective interaction Vτ for non-spin-flip ( 3He, t) charge exchange at E( 3He) ≈ 200 MeV. The interaction strength Vτ decreases by a factor 0.6 when compared to previously measured values for the energy range E( 3He) = 65 to 90 MeV. An angular distribution from θτ = 0° to 16° for the transition to the isobaric analog state in 120Sb measured at E( 3He) = 200 MeV was found to be in very good agreement with microscopic calculations.

  5. The n3He Experiment: Current Status

    NASA Astrophysics Data System (ADS)

    McCrea, Mark; n3He Collaboration

    2014-09-01

    The n3He experiment aims to make a high precision measurement of the hadronic weak interaction in the reaction n-> +3 He --> p + T by measuring the parity violating asymmetry in the direction of proton emission relative to the neutron polarization direction. As the weak interaction is the only interaction to violate parity this allows us to extract the much smaller weak interaction effects from the larger strong interaction effects. The range of the asymmetry is estimated to be (- 9 . 5 --> 2 . 5) ×10-8 . The goal is to measure this asymmetry with an accuracy of 2 ×10-8 to provide a benchmark for modern effective field theory calculations. n3He will run at the SNS Fundamental Neutron Physics Beamline. The combined target and detector is a multiwire 3He ionization chamber. A super mirror polarizer will be used to polarize the incoming cold neutron beam, and a spin flipper will reverse the spin in a sequence to control for systematic effects.

  6. Spin-polarized /sup 3/He nuclear targets and metastable /sup 4/He atoms by optical pumping with a tunable, Nd:YAP laser

    SciTech Connect

    Bohler, C.L.; Schearer, L.D.; Leduc, M.; Nacher, P.J.; Zachorowski, L.; Milner, R.G.; McKeown, R.D.; Woodward, C.E.

    1988-04-15

    Several Nd:YAP lasers were constructed which could be broadly tuned in the 1083-nm region which includes the helium 2/sup 3/S-2/sup 3/P transition, using a Lyot filter and thin, uncoated etalons within the laser cavity. 1 W of power could be extracted at 1083 nm through a 1% transmitting output coupler. This laser beam was used to optically pump metastable /sup 4/He and /sup 3/He 2/sup 3/S helium atoms in a weak discharge cell, spin polarizing the metastable ensemble. In a /sup 3/He cell the polarization is transferred to the nuclear spin system. A /sup 3/He target cell at 0.3 Torr was polarized to 52% in a few minutes. We describe the application of this system to the design of polarized targets for experiments in nuclear physics.

  7. Development of a Polarized 3He Ion Source for RHIC

    SciTech Connect

    Milner, Richard G.

    2013-01-15

    The goal of the project was to design and construct a source of polarized 3He atoms for injection into EBIS. This is the initial step in producing polarized 3He beams in RHIC in collaboration with physicists from Columbia University and Brookhaven National Laboratory. These beams can be used to probe the spin structure of the neutron in the existing RHIC complex as well as to measure precisely the Bjorken Sum Rule at a future eRHIC electron-ion collider.

  8. Novel and efficient 10B lined tubelet detector as a replacement for 3He neutron proportional counters

    NASA Astrophysics Data System (ADS)

    Tsorbatzoglou, Kyriakos; McKeag, Robert D.

    2011-10-01

    This paper presents a novel and robust proportional detector which addresses the well publicized shortage of 3He gas by using a 10B lining applied to a tubelet configuration. The advantage of the tubelet structure is that it yields a detector maintaining the form factor of a conventional 3He tube whilst achieving a sensitivity of up to 75% of a 3 atm 3He device. The design and fabrication of the tubelet detector is presented and discussed with test data comparing the new detector to existing 3He and BF 3 tubes. The application of the tubelet design to security and industrial applications including retro-fitting to existing portals and suitability for high integrity oil and gas installations is addressed.

  9. Polarized {sup 3}He gas compression system using metastability-exchange optical pumping

    SciTech Connect

    Hussey, D.S.; Rich, D.R.; Belov, A.S.; Tong, X.; Yang, H.; Bailey, C.; Keith, C.D.; Hartfield, J.; Hall, G.D.R.; Black, T.C.; Snow, W.M.; Gentile, T.R.; Chen, W.C.; Jones, G.L.; Wildman, E.

    2005-05-15

    Dense samples (10-100 bar cm) of nuclear spin polarized {sup 3}He are utilized in high energy physics, neutron scattering, atomic physics, and magnetic resonance imaging. Metastability exchange optical pumping can rapidly produce high {sup 3}He polarizations ({approx_equal}80%) at low pressures (few mbar). We describe a polarized {sup 3}He gas compressor system which accepts 0.26 bar l h{sup -1} of {sup 3}He gas polarized to 70% by a 4 W neodymium doped lanthanum magnesium hexaluminate (Nd:LMA) laser and compresses it into a 5 bar cm target with final polarization of 55%. The spin relaxation rates of the system's components have been measured using nuclear magnetic resonance and a model of the {sup 3}He polarization loss based on the measured relaxation rates and the gas flow is in agreement with a {sup 3}He polarization measurement using neutron transmission.

  10. Production of neutron-rich nuclides in the heavy-element region via /sup 3/He-induced reactions

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1982-01-01

    We have measured the production cross sections for /sup 233/Th and /sup 231/Th from the bombardment of /sup 238/U with /sup 3/He ions at 46-, 53-, and 60-MeV at the Brookhaven 60-in. isochronous cyclotron. We have also attempted to observe the decay of /sup 233/Ac produced via /sup 238/U(/sup 3/He,/sup 8/B) or equivalent reactions using 61 MeV /sup 3/He ions by first separating thorium from actinium and then performing chemical purifications on the second thorium sample into which the actinium has decayed. In the four experiments we performed, three gave results consistent with the ..beta.. half-life of /sup 233/Ac somewhat longer than 120 s and the production cross section from this target-projectile combination in the order of 1 to 2 ..mu..b.

  11. The 3He Supply Problem

    SciTech Connect

    Kouzes, Richard T.

    2009-05-01

    One of the main uses for 3He is in gas proportional counters for neutron detection. Radiation portal monitors deployed for homeland security and non-proliferation use such detectors. Other uses of 3He are for research detectors, commercial instruments, well logging detectors, dilution refrigerators, for targets or cooling in nuclear research, and for basic research in condensed matter physics. The US supply of 3He comes almost entirely from the decay of tritium used in nuclear weapons by the US and Russia. A few other countries contribute a small amount to the world’s 3He supply. Due to the large increase in use of 3He for homeland security, the supply has dwindled, and can no longer meet the demand. This white paper reviews the problems of supply, utilization, and alternatives.

  12. Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2.

    PubMed

    Qian, X; Allada, K; Dutta, C; Huang, J; Katich, J; Wang, Y; Zhang, Y; Aniol, K; Annand, J R M; Averett, T; Benmokhtar, F; Bertozzi, W; Bradshaw, P C; Bosted, P; Camsonne, A; Canan, M; Cates, G D; Chen, C; Chen, J-P; Chen, W; Chirapatpimol, K; Chudakov, E; Cisbani, E; Cornejo, J C; Cusanno, F; Dalton, M M; Deconinck, W; de Jager, C W; De Leo, R; Deng, X; Deur, A; Ding, H; Dolph, P A M; Dutta, D; El Fassi, L; Frullani, S; Gao, H; Garibaldi, F; Gaskell, D; Gilad, S; Gilman, R; Glamazdin, O; Golge, S; Guo, L; Hamilton, D; Hansen, O; Higinbotham, D W; Holmstrom, T; Huang, M; Ibrahim, H F; Iodice, M; Jiang, X; Jin, G; Jones, M K; Kelleher, A; Kim, W; Kolarkar, A; Korsch, W; LeRose, J J; Li, X; Li, Y; Lindgren, R; Liyanage, N; Long, E; Lu, H-J; Margaziotis, D J; Markowitz, P; Marrone, S; McNulty, D; Meziani, Z-E; Michaels, R; Moffit, B; Camacho, C Muñoz; Nanda, S; Narayan, A; Nelyubin, V; Norum, B; Oh, Y; Osipenko, M; Parno, D; Peng, J C; Phillips, S K; Posik, M; Puckett, A J R; Qiang, Y; Rakhman, A; Ransome, R D; Riordan, S; Saha, A; Sawatzky, B; Schulte, E; Shahinyan, A; Shabestari, M H; Sirca, S; Stepanyan, S; Subedi, R; Sulkosky, V; Tang, L-G; Tobias, A; Urciuoli, G M; Vilardi, I; Wang, K; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yuan, L; Zhan, X; Zhang, Y-W; Zhao, B; Zheng, X; Zhu, L; Zhu, X; Zong, X

    2011-08-12

    We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations. PMID:21902386

  13. A new ^3He-^129Xe Co-magnetometer using a Ramsey measurement sequence and Rb-K magnetometer for spin detection

    NASA Astrophysics Data System (ADS)

    Kabcenell, Aaron; Kominis, Iannis; Romalis, Michael

    2012-06-01

    Noble gas co-magnetometers have been used for many precision measurements, but their sensitivity is still very far from fundamental limits. We are exploring a new approach for operation of a ^3He-^129Xe co-magnetometer that uses a sensitive Rb-K magnetometer as a spin detector. By placing the noble gas atoms inside the magnetometer cell we can increase their magnetic signal using the Fermi-contact interaction, representing a gain of nearly 500 for ^129Xe, and achieve nearly quantum-noise limited detection of nuclear spins. In order to take advantage of the long coherence times of ^3He and^129Xe, the precession measurement is based on the Ramsey method of separated oscillatory fields and will be performed in an alkali-metal-free volume. The gas is then transported to the spin detector using techniques developed for remote NMR detection. The sensitivity of this approach is estimated to be on the order of 10-13 Hz/day^1/2, making it several orders of magnitude more sensitive than the best existing co-magnetometers. We are currently performing tests of the Ramsey measurement method and the sensitivity of the spin detector.

  14. Inclusive scattering of polarized electrons on polarized {sup 3}He: Effects of final state interaction and the magnetic form factor of the neutron

    SciTech Connect

    Ishikawa, S.; Golak, J.; Witala, H.; Kamada, H.; Gloeckle, W.; Hueber, D.

    1998-01-01

    Effects of final state interaction on asymmetries in inclusive scattering of polarized electrons on polarized {sup 3}He are investigated using a consistent {sup 3}He bound state wave function and 3N continuum scattering states. Significant effects are found, which influence the extraction of the magnetic neutron form factor from A{sub T{sup {prime}}}. The enhancement found experimentally for A{sub TL{sup {prime}}} near the 3N breakup threshold, which could not be explained in calculations carried through in plane wave impulse approximation up to now, occurs now also in theory if the full final state interaction is included. {copyright} {ital 1998} {ital The American Physical Society}

  15. Topological Septet Pairing with Spin-3/2 Fermions: High-Partial-Wave Channel Counterpart of the 3He -B Phase

    NASA Astrophysics Data System (ADS)

    Yang, Wang; Li, Yi; Wu, Congjun

    2016-08-01

    We systematically generalize the exotic 3He -B phase, which not only exhibits unconventional symmetry but is also isotropic and topologically nontrivial, to arbitrary partial-wave channels with multicomponent fermions. The concrete example with four-component fermions is illustrated including the isotropic f -, p -, and d -wave pairings in the spin septet, triplet, and quintet channels, respectively. The odd partial-wave channel pairings are topologically nontrivial, while pairings in even partial-wave channels are topologically trivial. The topological index reaches the largest value of N2 in the p -wave channel (N is half of the fermion component number). The surface spectra exhibit multiple linear and even high order Dirac cones. Applications to multiorbital condensed matter systems and multicomponent ultracold large spin fermion systems are discussed.

  16. Topological Septet Pairing with Spin-3/2 Fermions: High-Partial-Wave Channel Counterpart of the ^{3}He-B Phase.

    PubMed

    Yang, Wang; Li, Yi; Wu, Congjun

    2016-08-12

    We systematically generalize the exotic ^{3}He-B phase, which not only exhibits unconventional symmetry but is also isotropic and topologically nontrivial, to arbitrary partial-wave channels with multicomponent fermions. The concrete example with four-component fermions is illustrated including the isotropic f-, p-, and d-wave pairings in the spin septet, triplet, and quintet channels, respectively. The odd partial-wave channel pairings are topologically nontrivial, while pairings in even partial-wave channels are topologically trivial. The topological index reaches the largest value of N^{2} in the p-wave channel (N is half of the fermion component number). The surface spectra exhibit multiple linear and even high order Dirac cones. Applications to multiorbital condensed matter systems and multicomponent ultracold large spin fermion systems are discussed. PMID:27563972

  17. Spin-exchange optically pumped polarized 3He target for low-energy charged particle scattering experiments

    NASA Astrophysics Data System (ADS)

    Katabuchi, T.; Buscemi, S.; Cesaratto, J. M.; Clegg, T. B.; Daniels, T. V.; Fassler, M.; Neufeld, R. B.; Kadlecek, S.

    2005-03-01

    We have constructed, tested, and calibrated a polarized He3 target system which facilitates p-He3 elastic scattering at proton energies as low as 2MeV. This system consists of a target cell placed in a uniform B field inside a scattering chamber and an external optical pumping station utilizing Rb spin exchange. Computer-controlled valves allow polarized He3 gas to be transferred quickly between the optical pumping station and the spherical Pyrex target cell, which has Kapton film covering apertures for the passing beam and the scattering particles. The magnetic field required to maintain He3 polarization in the target cell is created with a compact, shielded sine-theta coil. Target gas polarimetry is accomplished using nuclear magnetic resonance and calibrated using the known analyzing power of α-He3 scattering.

  18. IEC-^3He Breeder for D-^3He Satellite Systems.

    NASA Astrophysics Data System (ADS)

    Chacon, L.; Miley, G. H.

    1996-11-01

    D-^3He fusion minimizes neutrons and maximizes charged fusion products, enabling increased energy recovery efficiency by direct conversion. However, scarce ^3He terrestrial resources have deterred R&D on this alternative. Here, we explore ^3He production through Inertial Electrostatic Confinement^1 (IEC) D-breeders, which supply ^3He to FRC D-^3He satellite reactors.^2 Favorable features for the IEC breeder include simplicity, low cost, easy extraction of fusion products, and compatibility with direct conversion. The breeder-satellite system energy balance is analyzed taking the net energy gain of the overall system, Q_N, as the figure of merit. Breeding is applicable for systems where the satellite Q-value, Q_S, > the breeder Q-value, Q_B. For improved performance, i.e., for high Q_N, QS >= QB >> 1 is needed; however, lower QB values (typical of the IEC) are permissible and still offer sufficient Q_N. An economic study determined breeding produces ^3He at a cost comparable to lunar ^3He, already shown to lead to competitive power.^3 The cost of electricity (COE) for the breeder-satellite complex was compared with the ARTEMIS COE,^4 using lunar ^3He fuel: assuming one satellite (1000 MWe)/breeder (170 MWe), the ratio of the breeding system COE to the lunar mining base COE is ~ 1.2. However, economic breeding is driven by large IEC breeder powers, i.e., increased ^3He breeding rates. Thus, the COE ratio approaches unity with two or three satellites/breeder, requiring increased breeder size and power (340 MWe for 2 satellites, 510 MWe for 3 satellites). Such systems potentially provide a ``bridge'' to a future lunar ^3He economy. 1. G.H. Miley et al., Dense Z-pinches, AIP Conf. 299, AIP Press, 675-689 (1994). 2. G.H. Miley, Nucl. Instrum. Methods, A271, 197-202 (1988). 3. L.J. Wittenberg et al., Fusion Technol., 10, 167-178 (1986). 4. H. Momota et al., Fusion Technol., 21, 2307-2323 (1992).

  19. Single spin asymmetries in charged kaon production from semi-inclusive deep inelastic scattering on a transversely polarized 3He target

    NASA Astrophysics Data System (ADS)

    Zhao, Y. X.; Wang, Y.; Allada, K.; Aniol, K.; Annand, J. R. M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M. M.; Deconinck, W.; de Jager, C. W.; De Leo, R.; Deng, X.; Deur, A.; Ding, H.; Dolph, P. A. M.; Dutta, C.; Dutta, D.; El Fassi, L.; Frullani, S.; Gao, H.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Guo, L.; Hamilton, D.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, J.; Huang, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; Katich, J.; Kelleher, A.; Kim, W.; Kolarkar, A.; Korsch, W.; LeRose, J. J.; Li, X.; Li, Y.; Lindgren, R.; Liyanage, N.; Long, E.; Lu, H.-J.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; McNulty, D.; Meziani, Z.-E.; Michaels, R.; Moffit, B.; Muñoz Camacho, C.; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J.-C.; Phillips, S. K.; Posik, M.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Rakhman, A.; Ransome, R.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Širca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, A.; Urciuoli, G. M.; Vilardi, I.; Wang, K.; Wojtsekhowski, B.; Yan, X.; Yao, H.; Ye, Y.; Ye, Z.; Yuan, L.; Zhan, X.; Zhang, Y.; Zhang, Y.-W.; Zhao, B.; Zheng, X.; Zhu, L.; Zhu, X.; Zong, X.; Jefferson Lab Hall A Collaboration

    2014-11-01

    We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1

  20. The Art of Neutron Spin Flipping

    NASA Astrophysics Data System (ADS)

    Lieffers, Justin; Holley, Adam; Snow, W. M.

    2014-09-01

    Low energy precision measurements complement high energy collider results in the search for physics beyond the Standard Model. Neutron spin rotation is a sensitive technique to search for possible exotic velocity and spin-dependent interactions involving the neutron from the exchange of light (~ meV) spin 1 bosons. We plan to conduct such searches using beams of cold neutrons at the Los Alamos Neutron Science Center (LANSCE) and the National Institute of Standards and Technology (NIST). To change the spin state of the neutrons in the apparatus we have developed an Adiabatic Fast Passage (AFP) neutron spin flipper. I will present the mechanical design, static and RF magnetic field modeling and measurements, and spin flip efficiency optimization of the constructed device. I would like to acknowledge the NSF REU program (NSF-REU grant PHY-1156540) and the Indiana University nuclear physics group (NSF grant PHY-1306942) for this opportunity.

  1. PREFACE: JCNS Workshop on Modern Trends in Production and Applications of Polarized 3He

    NASA Astrophysics Data System (ADS)

    Ioffe, Alexander; Babcock, Earl; Gutberlet, Thomas

    2011-03-01

    Polarized neutron scattering techniques are an indispensable and highly requested tool for studying magnetic phenomena in condensed matter. The different coherent and incoherent scattering of isotopes such as protons and deuterons also allows applications of polarized neutrons in soft matter and biological studies of molecular and macromolecular dynamics. One method to polarize neutrons is to use polarized 3He gas which absorbs, or filters, one spin state of the neutron beam as it passes through it. Only about ten years ago, early polarized neutron scattering experiments using such 3He neutron spin filters (3He NSF) were being conducted using starting 3He polarizations of 55%. Currently there are two different commonly used methods to polarize high quantities of 3He. These methods both collisionally transfer spin polarization to ground state 3He nucleuses; one method uses optical pumping of an excited metastable state of 3He atoms, and the other uses optical pumping of the ground state of an alkali-metal vapour. Within the last decade immense progress in both methods has resulted in 3He polarizations of up to 80% being reported in atmosphere-pressure 3He cells by the world's leading labs. This progress in optical pumped 3He promises to give rise to much more efficient and novel polarized neutron scattering experiments as and also impacts other areas of science. Polarized 3He is additionally applied in research fields such as particle physics, fundamental studies and medicine. Thus not only the techniques and methods of polarization, but the research groups themselves exploring polarized 3He, have a large breadth and diversity spanning different fields of science and locations in the world. Given this diversity, it is rare for this community to meet as a group at any one meeting or conference. Because it is crucial to discuss new developments in 3He polarization in a multi-disciplinary international setting, an international workshop on "Modern Trends in Production

  2. {sup 3}He polarization via optical pumping in a birefringent cell

    SciTech Connect

    Masuda, Y.; Ino, T.; Skoy, V.R.; Jones, G.L.

    2005-08-01

    A sapphire cell was used to obtain a high {sup 3}He nuclear polarization by means of spin-exchange optical pumping. The phase-shift difference between ordinary and extraordinary rays is well controlled using the thickness of the birefringent sapphire window so that a high circular polarization is obtained in the cell. Neutron transmission through the polarized {sup 3}He gas was measured as a function of neutron energy. A large {sup 3}He polarization of 63{+-}1% was obtained at a {sup 3}He pressure of 3.1 atm. Neutron polarizations of 97 and 90 % were obtained with transmission rates of 15 and 22 % at 10 and 20 meV, respectively.

  3. Investigation of the {sup 3}He wave function by quasifree scattering

    SciTech Connect

    Jones, C.E.; Hansen, J.O.; Bloch, C.

    1995-08-01

    The analysis of the data from the CE25 experiment at IUCF, which measured the target and beam analyzing powers and the spin correlation parameter in {sup 3}He(p,2p) and {sup 3}He(p,pn) quasielastic scattering, is nearing completion. At low missing momentum, the extracted polarization of the neutron and proton in {sup 3}He are consistent with Faddeev calculations. Two papers, one reporting the physics results and one describing the experiment, were published. The data from this experiment indicates that for q {>=} 500 MeV/c the plane wave impulse approximation is valid.

  4. A white beam neutron spin splitter

    SciTech Connect

    Krist, T.; Klose, F.; Felcher, G.P.

    1997-07-23

    The polarization of a narrow, highly collimated polychromatic neutron beam is tested by a neutron spin splitter that permits the simultaneous measurement of both spin states. The device consists of a Si-Co{sub 0.11} Fe{sub 0.89} supermirror, which totally reflects one spin state up to a momentum transfer q=0.04 {angstrom}{sup -1}, whilst transmits neutrons of the opposite spin state. The supermirror is sandwitched between two thick silicon wafers and is magnetically saturated by a magnetic field of 400 Oe parallel to its surface. The neutron beam enters through the edge of one of the two silicon wavers, its spin components are split by the supermirror and exit from the opposite edges of the two silicon wafers and are recorded at different channels of a position-sensitive detector. The device is shown to have excellent efficiency over a broad range of wavelengths.

  5. Burst Oscillations: Watching Neutron Stars Spin

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod

    2010-01-01

    It is now almost 15 years since the first detection of rotationally modulated emission from X-ray bursting neutron stars, "burst oscillations," This phenomenon enables us to see neutron stars spin, as the X-ray burst flux asymmetrically lights up the surface. It has enabled a new way to probe the neutron star spin frequency distribution, as well as to elucidate the multidimensional nature of nuclear burning on neutron stars. I will review our current observational understanding of the phenomenon, with an eye toward highlighting some of the interesting remaining puzzles, of which there is no shortage.

  6. A Search for Exotic Spin-Dependent Interactions of the Neutron using Neutron Spin Rotation

    NASA Astrophysics Data System (ADS)

    Haddock, Chris; Nsr Collaboration

    2016-03-01

    Many theories beyond the Standard Model lead at low energy to spin-dependent, weakly-coupled interactions of mesoscopic range. Laboratory constraints on such interactions are quite poor. We describe an experiment in progress at the LANSCE spallation neutron source at Los Alamos to search for exotic axial couplings of neutrons to matter from light vector boson exchange. The experiment makes use of a slow neutron polarimeter and a target with an oscillating mass density. Neutron Spin Rotation.

  7. Development of polarized 3He ion source

    NASA Astrophysics Data System (ADS)

    Tanaka, M.; Takahashi, Y.; Shimoda, T.; Yasui, S.; Yosoi, M.; Takahisa, K.; Shimakura, N.

    2007-02-01

    A long history on the polarized 3He ion source developed at RCNP is presented. We started with an "OPPIS" (Optical Pumping Polarized Ion Source) and later found the fundamental difficulties in the OPPIS. To overcome them an "EPPIS" (Electron Pumping Polarized Ion Source) was proposed and its validity was experimentally proven. However, a serious technical disadvantage was also found in the EPPIS. To avoid this disadvantage we proposed a new concept, "SEPIS" (Spin Exchange Polarized Ion Source), which uses an enhanced spin-exchange cross section theoretically expected at low 3He+ incident energies for the 3He+ + Rb system. Next, we describe the present status of the SEPIS development; construction of a bench test device allowing the measurements of not only the spin-exchange cross sections σse but also the electron capture cross sections σec for the 3He+ + Rb system. The latest experimental data on σec are presented and compared with other previous experimental data and the theoretical calculations. A design study of the SEPIS for practical use in nuclear (cyclotron) and particle physics (synchrotron) is shortly mentioned. Finally, we mention possibility to polarize ions heavier than 3He as an application of SEPIS. The theoretical calculation showed that σse comparable to that for the 3He+ + Rb is expected for the Li2+ + Rb system, which suggests that the SEPIS will hopefully be a general tool to polarize any heavy ions.

  8. A Precision Measurement of the Transverse Asymmetry A{sub T} from Quasi-elastic {sup 3}He(e,e') process, and the Neutron Magnetic Form Factor GNM at low Q{sup 2}

    SciTech Connect

    Wang Xu

    2002-06-01

    Electromagnetic form factors are fundamental quantities in describing the underlying electromagnetic structure of nucleons. While proton electromagnetic form factors have been determined with good precision, neutron form factors are known poorly, largely due to the lack of free neutron targets. Jefferson Lab Hall A experiment E95-001, a ''precise measurement of the transverse asymmetry A{sub T}' from the quasielastic {sup 3}He(e, e') process,'' was therefore designed to determine precisely the neutron magnetic form factor, G{sub M}{sup n} at low momentum transfer values and was successfully completed in Spring 1999. High precision A{sub T}'data in the quasi-elastic region at Q{sup 2} values of 0.1 to 0.6 (GeV/c){sup 2} were obtained using a high-pressure spin-exchange optically-pumped polarized {sup 3}He gas target with an average polarization of 30%, a longitudinally polarized e{sup -} beam, and two High Resolution Spectrometers: HRSe and HRSh. HRSe was employed to detect scattered electrons from the quasi-elastic kinematic region, and HRSh was employed as a elastic polarimetry to monitor the product of the beam and target polarizations. The extraction of form factors is usually model-dependent. Significant constraints on theoretical calculations are provided bu additional high precision quasi-elastic asymmetry data at Q{sup 2} values of 0.1 and 0.2 (GeV/c){sup 2} in {sup 3}He breakup region, where effects of final state interactions (FSI) and meson exchange currents (MEC) are expected to be large [71]. G{sub M}{sup n} is extracted from a non-relativistic Faddeev calculation which includes both FSI and MEC at Q{sup 2} values of 0.1 and 0.2 (GeV/c){sup 2}. The uncertainties of G{sub M}{sup n} at these Q{sup 2} values are comparable to those of recent experiments with deuterium targets [58]. At the higher Q{sup 2} values from this experiment, G{sub M}{sup n} is extracted from Plane-Wave Impulsive Approximation (PWIA) calculations with a relatively large theoretical

  9. Theory of (3He,(alpha)) surrogate reactions for deformed uranium nuclei

    SciTech Connect

    Thompson, I; Escher, J E

    2006-11-08

    We present the one-step theory of neutron-pickup transfer reactions with {sup 3}He projectiles on {sup 235}U and {sup 238}U. We find all the neutron eigenstates in a deformed potential, and use those in a given energy range for ({sup 3}He, {alpha}) DWBA pickup calculations to find the spin and parity distributions of the residual target nuclei. A simple smoothing convolution is used to take into account the spreading width of the single-neutron hole states into the more complicated compound nuclear states. We assume that the initial target is an even-even rotor, but can take into account spectator neutrons outside such a rotor by recombining their spin and parity at the end of the calculations.

  10. Neutron spin echo scattering angle measurement (SESAME)

    SciTech Connect

    Pynn, R.; Fitzsimmons, M.R.; Fritzsche, H.; Gierlings, M.; Major, J.; Jason, A.

    2005-05-15

    We describe experiments in which the neutron spin echo technique is used to measure neutron scattering angles. We have implemented the technique, dubbed spin echo scattering angle measurement (SESAME), using thin films of Permalloy electrodeposited on silicon wafers as sources of the magnetic fields within which neutron spins precess. With 30-{mu}m-thick films we resolve neutron scattering angles to about 0.02 deg. with neutrons of 4.66 A wavelength. This allows us to probe correlation lengths up to 200 nm in an application to small angle neutron scattering. We also demonstrate that SESAME can be used to separate specular and diffuse neutron reflection from surfaces at grazing incidence. In both of these cases, SESAME can make measurements at higher neutron intensity than is available with conventional methods because the angular resolution achieved is independent of the divergence of the neutron beam. Finally, we discuss the conditions under which SESAME might be used to probe in-plane structure in thin films and show that the method has advantages for incident neutron angles close to the critical angle because multiple scattering is automatically accounted for.

  11. Measurement of the neutron electric to magnetic form factor ratio at Q2=1.58  GeV2 using the reaction 3He[over →](e[over →],e'n)pp.

    PubMed

    Schlimme, B S; Achenbach, P; Ayerbe Gayoso, C A; Bernauer, J C; Böhm, R; Bosnar, D; Challand, Th; Distler, M O; Doria, L; Fellenberger, F; Fonvieille, H; Gómez Rodríguez, M; Grabmayr, P; Hehl, T; Heil, W; Kiselev, D; Krimmer, J; Makek, M; Merkel, H; Middleton, D G; Müller, U; Nungesser, L; Ott, B A; Pochodzalla, J; Potokar, M; Sánchez Majos, S; Sargsian, M M; Sick, I; Sirca, S; Weinriefer, M; Wendel, M; Yoon, C J

    2013-09-27

    A measurement of beam helicity asymmetries in the reaction 3He[over →](e[over →],e'n)pp is performed at the Mainz Microtron in quasielastic kinematics to determine the electric to magnetic form factor ratio of the neutron GEn/GMn at a four-momentum transfer Q2=1.58  GeV2. Longitudinally polarized electrons are scattered on a highly polarized 3He gas target. The scattered electrons are detected with a high-resolution magnetic spectrometer, and the ejected neutrons are detected with a dedicated neutron detector composed of scintillator bars. To reduce systematic errors, data are taken for four different target polarization orientations allowing the determination of GEn/GMn from a double ratio. We find μnGEn/GMn=0.250±0.058(stat)±0.017(syst). PMID:24116774

  12. Studies of 3He polarization losses during NMR and EPR measurment and Polarized 3He target cell lifetime

    NASA Astrophysics Data System (ADS)

    An, Peibo

    2014-09-01

    The 3He target cell polarized by spin-exchange optical pumping(SEOP) is used as a neutron substitute to study the inner structure of the neutron. In our lab, nuclear-magnetic-resonance(NMR) is used to measure the relative polarization and electron-paramagnetic-resonance(EPR) is used to measure the spin exchange EPR frequency shift parameter of potassium and rubidium in our target cell presented in magnetic fields. The alkali in the cell is used to facilitate the polarization of 3He. The first part of my work presents the study of the polarization losses of the cell during both NMR and EPR. With the help of improved RF coils, we keep the background noise received by pickup coils reasonably low, but three other kinds of losses are inevitable: losses during Adiabatic Fast Passage (AFP) sweep, losses due to flux change caused by different cell orientation with respect to RF fields and physical losses. Fortunately there is only flux change in NMR measurements. The second part of my work presents the study of cell lifetime improvement. The polarization decreases in a process called relaxation exponentially. The lifetime of a cell is how long it can keep its polarization. The typical lifetime of cells produced in our lab is about 22 hours. With a newly designed vacuum system. The 3He target cell polarized by spin-exchange optical pumping(SEOP) is used as a neutron substitute to study the inner structure of the neutron. In our lab, nuclear-magnetic-resonance(NMR) is used to measure the relative polarization and electron-paramagnetic-resonance(EPR) is used to measure the spin exchange EPR frequency shift parameter of potassium and rubidium in our target cell presented in magnetic fields. The alkali in the cell is used to facilitate the polarization of 3He. The first part of my work presents the study of the polarization losses of the cell during both NMR and EPR. With the help of improved RF coils, we keep the background noise received by pickup coils reasonably low, but

  13. Results on Double-polarization Asymmetries in Quasielastic Scattering from Polarized 3He

    NASA Astrophysics Data System (ADS)

    Sulkosky, Vincent A.

    2016-03-01

    The 3He nucleus has become extremely important in the investigation of the neutron's spin structure. When polarized, 3He acts as an effective polarized neutron target and hence facilitates our understanding of the neutron's internal structure. However, to be used in this manner, our understanding of the internal structure of 3He is of extreme importance. As the precision of experiments has improved, the extraction of polarized neutron information from 3He leads to an ever larger share of the systematic uncertainty for these experiments. In these proceedings, I present a precise measurement of beam-target asymmetries in the {}^3overrightarrow {He} (e,e'd) and {}^3overrightarrow {He} (e,e'p) reactions. The former process is a uniquely sensitive probe of hadron dynamics in 3He and the structure of the underlying electromagnetic currents. The measurements have been performed around the quasi-elastic peak at Q2 = 0.25 (GeV/c)2 and 0.35 (GeV/c)2 for recoil momenta up to 270 MeV/c. The experimental apparatus, analysis and results were presented together with a comparison to state-of-the art Faddeev calculations.

  14. /sup 3/He functions in tokamak-pumped laser systems

    SciTech Connect

    Jassby, D.L.

    1986-10-01

    /sup 3/He placed in an annular cell around a tokamak fusion generator can convert moderated fusion neutrons to energetic ions by the /sup 3/He(n,p)T reaction, and thereby excite gaseous lasants mixed with the /sup 3/He while simultaneously breeding tritium. The total /sup 3/He inventory is about 4 kg for large tokamak devices. Special configurations of toroidal-field magnets, neutron moderators and beryllium reflectors are required to permit nearly uniform neutron current into the laser cell with minimal attenuation. The annular laser radiation can be combined into a single output beam at the top of the tokamak.

  15. Asymmetries in electron-induced breakup of polarized {sup 3}He

    SciTech Connect

    Sirca, Simon

    2011-10-01

    The Jefferson Lab Experiment E05-102 "Measurement of A{sub x}' and A{sub z}' asymmetries in the quasi-elastic {sup 3}He(e,e'd) reaction" was performed in Hall A in 2009. The main physics motivation of the experiment was to investigate the effects of small components of the {sup 3}He ground-state wave-function by a simultaneous measurement of double-polarization asymmetries in quasi-elastic kinematics for three exclusive channels, (e,e'd), (e,e'p), and (e,e'n), at almost identical momentum transfers, as well as for (e,e'). This experiment will help map the spin structure of the {sup 3}He nucleus onto the picture of the "free" polarized neutron. As such, it is of great relevance to the polarized-neutron programs at Jefferson Lab and beyond.

  16. Asymmetries in electron-induced breakup of polarized {sup 3}He

    SciTech Connect

    Sirca, S.

    2011-10-24

    The Jefferson Lab Experiment E05-102 'Measurement of A{sub x}{sup '} and A{sub z}{sup '} asymmetries in the quasi-elastic {sup 3}He(e,e'd) reaction' was performed in Hall A in 2009. The main physics motivation of the experiment was to investigate the effects of small components of the {sup 3}He ground-state wave-function by a simultaneous measurement of double-polarization asymmetries in quasi-elastic kinematics for three exclusive channels, (e,e'd), (e,e'p), and (e,e'n), at almost identical momentum transfers, as well as for (e,e'). This experiment will help map the spin structure of the {sup 3}He nucleus onto the picture of the ''free'' polarized neutron. As such, it is of great relevance to the polarized-neutron programs at Jefferson Lab and beyond.

  17. First measurements of spin-dependent double-differential cross sections and the Gerasimov-Drell-Hearn Integrand from 3He(γ,n)pp at incident photon energies of 12.8 and 14.7 MeV.

    PubMed

    Laskaris, G; Ye, Q; Lalremruata, B; Ye, Q J; Ahmed, M W; Averett, T; Deltuva, A; Dutta, D; Fonseca, A C; Gao, H; Golak, J; Huang, M; Karwowski, H J; Mueller, J M; Myers, L S; Peng, C; Perdue, B A; Qian, X; Sauer, P U; Skibiński, R; Stave, S; Tompkins, J R; Weller, H R; Witała, H; Wu, Y K; Zhang, Y; Zheng, W

    2013-05-17

    The first measurement of the three-body photodisintegration of longitudinally polarized (3)He with a circularly polarized γ-ray beam was carried out at the High Intensity γ-ray Source facility located at Triangle Universities Nuclear Laboratory. The spin-dependent double-differential cross sections and the contributions from the three-body photodisintegration to the (3)He Gerasimov-Drell-Hearn integrand are presented and compared with state-of-the-art three-body calculations at the incident photon energies of 12.8 and 14.7 MeV. The data reveal the importance of including the Coulomb interaction between protons in three-body calculations. PMID:25167400

  18. Effective spin-spin interaction in neutron matter

    SciTech Connect

    Zverev, M.V.; Khafizov, R.U.; Khodel, V.A.; Shaginyan, V.R.

    1995-09-01

    A set of equations for calculating the effective-interaction matrix R{sup ik}(q, {omega}) and the response function X{sup ik}(q, {omega}) is derived. These equations take into account the spin degrees of freedom of infinite neutron matter. For isotropic neutron matter with the Bethe interaction, the effective spin-spin interaction g(k) is calculated in the local approximation of the functional approach in the density range from {rho} = 0.17 to 25 fm{sup -3}. It is shown that this interaction weakly depends on the density within the range under consideration and that neither ferromagnetic nor antiferromagnetic phase transitions occur in the system. 7 refs., 2 figs.

  19. Spin distribution in neutron induced preequilibrium reactions

    SciTech Connect

    Dashdorj, D; Kawano, T; Chadwick, M; Devlin, M; Fotiades, N; Nelson, R O; Mitchell, G E; Garrett, P E; Agvaanluvsan, U; Becker, J A; Bernstein, L A; Macri, R; Younes, W

    2005-10-04

    The preequilibrium reaction mechanism makes an important contribution to neutron-induced reactions above E{sub n} {approx} 10 MeV. The preequilibrium process has been studied exclusively via the characteristic high energy neutrons produced at bombarding energies greater than 10 MeV. They are expanding the study of the preequilibrium reaction mechanism through {gamma}-ray spectroscopy. Cross-section measurements were made of prompt {gamma}-ray production as a function of incident neutron energy (E{sub n} = 1 to 250 MeV) on a {sup 48}Ti sample. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the Los Alamos Neutron Science Center facility. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed Germanium Array for Neutron Induced Excitations (GEANIE). Neutron energies were determined by the time-of-flight technique. The {gamma}-ray excitation functions were converted to partial {gamma}-ray cross sections taking into account the dead-time correction, target thickness, detector efficiency and neutron flux (monitored with an in-line fission chamber). Residual state population was predicted using the GNASH reaction code, enhanced for preequilibrium. The preequilibrium reaction spin distribution was calculated using the quantum mechanical theory of Feshback, Kerman, and Koonin (FKK). The multistep direct part of the FKK theory was calculated for a one-step process. The FKK preequilibrium spin distribution was incorporated into the GNASH calculations and the {gamma}-ray production cross sections were calculated and compared with experimental data. The difference in the partial {gamma}-ray cross sections using spin distributions with and without preequilibrium effects is significant.

  20. Equilibrium spin pulsars unite neutron star populations

    NASA Astrophysics Data System (ADS)

    Ho, Wynn; Klus, Helen; Coe, Malcolm; Andersson, Nils

    2015-08-01

    We compare the large number of recent torque measurements of accreting pulsars with a high-mass companion to the standard model for how accretion affects the pulsar spin period. We find that many long spin period (P > 100 s) pulsars must possess either extremely weak (B < 10^10 G) or extremely strong (B > 10^14 G) magnetic fields. We argue that the strong-field solution is more compelling, in which case these pulsars are near spin equilibrium. Our results provide evidence for a fundamental link between pulsars with the slowest spin periods and strong magnetic fields around high-mass companions and pulsars with the fastest spin periods and weak fields around low-mass companions. The strong magnetic fields also connect our pulsars to magnetars and strong-field isolated radio/X-ray pulsars. The strong field and old age of our sources suggests their magnetic field penetrates into the superconducting core of the neutron star.

  1. Single-particle strength in neutron-rich 69Cu from the 70Zn(d ,3He)69Cu proton pick-up reaction

    NASA Astrophysics Data System (ADS)

    Morfouace, P.; Franchoo, S.; Sieja, K.; Stefan, I.; de Séréville, N.; Hammache, F.; Assié, M.; Azaiez, F.; Borcea, C.; Borcea, R.; Grassi, L.; Guillot, J.; Le Crom, B.; Lefebvre, L.; Matea, I.; Mengoni, D.; Napoli, D.; Petrone, C.; Stanoiu, M.; Suzuki, D.; Testov, D.

    2016-06-01

    We have performed the 70Zn(d ,3He)69Cu proton pick-up reaction in direct kinematics using a deuteron beam at 27 MeV. The outgoing 3He particles were detected at the focal-plane detection system of an Enge split-pole spectrometer. The excitation-energy spectrum was reconstructed up to 7 MeV and spectroscopic factors were obtained after analysis of the angular distributions in the finite-range distorted-wave Born approximation. The results show three new angular distributions for which the π f7 /2 strength was measured and a lower limit of the centroid is established. State-of-the-art shell-model calculations are performed and predict a π f7 /2 strength that lies too high in energy in comparison to our experimental results.

  2. Precision measurement of the neutron spin dependent structure functions

    SciTech Connect

    Kolomensky, Y.G.

    1997-02-01

    In experiment E154 at the Stanford Linear Accelerator Center the spin dependent structure function g{sub 1}{sup n} (x, Q{sup 2}) of the neutron was measured by scattering longitudinally polarized 48.3 GeV electrons off a longitudinally polarized {sup 3}He target. The high beam energy allowed the author to extend the kinematic coverage compared to the previous SLAC experiments to 0.014 {le} x {le} 0.7 with an average Q{sup 2} of 5 GeV{sup 2}. The author reports the integral of the spin dependent structure function in the measured range to be {integral}{sub 0.014}{sup 0.7} dx g{sub 1}{sup n}(x, 5 GeV{sup 2}) = {minus}0.036 {+-} 0.004(stat.) {+-} 0.005(syst.). The author observes relatively large values of g{sub 1}{sup n} at low x that call into question the reliability of data extrapolation to x {r_arrow} 0. Such divergent behavior disagrees with predictions of the conventional Regge theory, but is qualitatively explained by perturbative QCD. The author performs a Next-to-Leading Order perturbative QCD analysis of the world data on the nucleon spin dependent structure functions g{sub 1}{sup p} and g{sub 1}{sup n} paying careful attention to the experimental and theoretical uncertainties. Using the parameterizations of the helicity-dependent parton distributions obtained in the analysis, the author evolves the data to Q{sup 2} = 5 GeV{sup 2}, determines the first moments of the polarized structure functions of the proton and neutron, and finds agreement with the Bjorken sum rule.

  3. Spin-orbit splitting in neutron drops

    SciTech Connect

    Pieper, S.C.; Pandharipande, V.R.; Ravenhall, D.G.

    1995-08-01

    Hartree-Fock calculations of very neutron-rich nuclei are an essential source of input for calculations of the properties of neutron-star crusts. The Hartree-Fock calculations often use Skyrme models whose parameters are determined by fits to known (hence not neutron-rich) nuclei and extrapolations to the N >> Z case. The Vautherin and Brink (VB) prescription for the isospin dependence of the spin-orbit potential, V{sub so}, is usually used; this is based on the assumption that most of V{sub so} comes from a short-range L{center_dot}S nucleon-nucleon interaction. In 1993 we showed that more than half of the spin-orbit splitting in {sup 15}N comes from long-range three-nucleon potentials and correlations, which violate the VB assumption. To investigate the isospin dependence of the spin-orbit splitting, we made calculations of the type described in Sec. B.d for systems of 7 (p-wave splitting) and 19 (d-wave) neutrons. The neutrons were confined in external potentials that were adjusted to give physically reasonable densities. We find that the spin-orbit splitting of these drops is less than half the {sup 15}N value. These values can be used to determine an isospin dependence of V{sub so} that is very different from that of VB. Hartree-Fock calculations of known spin-orbit splittings in nuclei with N significantly different from Z are now being made with this new prescription.

  4. Investigation of Neutron Emissions from D(d,n)3He and T(d,n)4He Reactions in a 10 TW Picosecond Laser Facility SOKOL-P

    SciTech Connect

    Andriyash, A. V.; Andryushin, V. V.; Chefonov, O. V.; Chizhkov, M. N.; Dmitrov, D. A.; Kakshin, A. G.; Kapustin, I. A.; Levin, A. V.; Loboda, E. A.; Lykov, V. A.; Pronin, V. A.; Pokrovskiy, V. G.; Potapov, A. V.; Sanzhin, V. N.; Saprykin, V. N.; Ugodenko, A. A.; Vihklyaev, D. A.; Zapysov, A. L.; Zuev, Yu. N.

    2006-08-03

    Experimental results on fast neutron generation in D(d,n)3He and T(d,n)4He reactions in the SOKOL-P laser facility are presented. Solid targets were irradiated by 1.054 {mu}m, s- or p-polarized laser pulses of energy 5-8 J on target and duration 0.85-2 ps. The peak laser intensity was 0.5-2{center_dot}1018 W/cm2. Flat deuterated plastic (CD2)n targets and TiD0.5T0.5 targets were used in experiments. Some experiments were carried out with additional targets placed in front of and behind the laser target. The used time-of-flight technique helped identify neutrons from D(d,n)3He and T(d,n)4He reactions. Yields up to 106 DD-neutrons and 107 DT-neutrons were measured. Interaction of the fast ion beam with the target can explain the observed yield.

  5. Nuclear Ordered Phases of Solid 3He in Silver Sinters

    NASA Astrophysics Data System (ADS)

    Schuberth, Erwin A.; Kath, Matthias; Bago, Simone

    2006-09-01

    To determine the exact spin structure of the nuclear magnetic ordered phases of solid 3He, the U2D2 low field and the high field phases above 0.4 T, a European Research and Training Network for neutron scattering from the ordered solid was established which consisted of a collaboration with the Hahn Meitner Institute, Berlin, and other European and US groups. For this experiment it is crucial to grow a single crystal within the sinter needed for cooling the solid to temperatures of the order of 500 μK and to keep it cold long enough to measure a magnetic neutron diffraction. The sinter is also necessary to absorb the major part (> 90%) of the heat generated by the neutron capture and decay reaction of the 3He nucleus. In this work we studied the growth of crystals in Ag sinters of different pore sizes and with different growth speeds to find an optimal way to obtain single crystalline samples, or at least samples with only a few grains. We used SQUID magnetometry and NMR to measure the magnetization in the ordered phases. They were indicated by the known drop of the intensity, both in the NMR signal and in the dc magnetization, for the U2D2 phase, and by an increase of about 30% for the high field phase. The best results for cooling were obtained with sinters made from 700 Å "Japanese powder" with a packing fraction of 50% which were annealed at 130 °C after sintering and then had a calculated particle size of about 4200 Å. In the dc magnetization we found a paramagnetic surface contribution from a few monolayers of 3He down to 500 μK in addition to the bulk magnetization.

  6. Nuclear electric dipole moment of 3He

    SciTech Connect

    Stetcu, Ionel; Friar, J L; Hayes, A C; Liu, C P; Navratil, P

    2008-01-01

    In the no-core shell model (NCSM) framework, we calculate the {sup 3}He electric dipole moment (EDM) generated by parity- and time-reversal violation in the nucleon-nucleon interaction. While the results are somehow sensitive to the interaction model chosen for the strong two- and three-body interactions, we demonstrate the pion-exchange dominance to the EDM of {sup 3}He, if the coupling constants for {pi}, {rho} and {omega}-exchanges are of comparable magnitude, as expected. Finally, our results suggest that a measurement of {sup 3}He EDM would be complementary to the currently planned neutron and deuteron experiments, and would constitute a powerful constraint to the models of the pion P- and T-violating interactions.

  7. Dislocation motion in solid hcp 3He

    NASA Astrophysics Data System (ADS)

    Beamish, John; Cheng, Zhi Gang

    At temperatures above about 100 mK, dislocations reduce the shear modulus of hcp 4He by as much as 90 %. This occurs when dislocations thermally unbind from the 3He impurities that pin them, becoming extraordinarily mobile. The elastic softening is accompanied by a thermally activated dissipation peak due to the 3He impurities. At higher temperatures the dissipation has an ωT4 dependence caused by scattering of thermal phonons from moving dislocations. Previous measurements on the fermi solid, hcp 3He, showed a similar dislocation softening, but the corresponding dissipation was not measured. We have extended these measurements by measuring the temperature, amplitude and frequency dependence of both the shear modulus and the dissipation in hcp 3He. The dissipation behavior is very different from that of hcp 4He. Neither the impurity unbinding peak associated with the elastic softening, nor the high temperature phonon scattering dissipation, were observed. Instead, there is a large and non-thermally activated dissipation which is largest at low frequencies. We believe that this unexpected dissipation is associated with a new dislocation damping mechanism in 3He, perhaps associated with spin rearrangements caused by moving dislocations. This work was supported by a grant from NSERC Canada.

  8. Attenuation of ambient dose equivalent from neutrons by thick concrete, cast iron and composite shields for high energy proton, 3He, 48Ca and 238U ions on Cu targets for shielding design

    NASA Astrophysics Data System (ADS)

    Iwamoto, Yosuke; Ronningen, R. M.

    2011-02-01

    Data on neutron dose attenuation by thick concrete, cast iron, and cast iron plus concrete composite shields for heavy ions and protons having high energies (200-1000 MeV/u) are necessary for shielding designs of high-powered heavy ion accelerator facilities. Neutron production source terms, shield material attenuation lengths, and neutron dose rate reduction effectiveness of the bulk shielding in the angular range from 0° to 125° were determined by the Particle and Heavy Ion Transport Code (PHITS) for beams of 300 and 550 MeV/u 48Ca ions, 200 and 400 MeV/u 238U ions, 800 MeV/u 3He and 1 GeV protons. Calculated results of interaction lengths of concrete and cast iron were also compared with similar work performed by Agosteo et al., and to experimental and other calculated data on interaction lengths. The agreement can be regarded as acceptable.

  9. Isospin-spin excitations in the A=58 mass region: The {sup 58}Ni({sup 3}He,t){sup 58}Cu reaction

    SciTech Connect

    Bes, D. R.; Civitarese, O.

    2008-07-15

    The experimental information on isospin-spin excitations around {sup 58}Ni is analyzed by using isoscalar and isovector pairing vibrations, Gamow-Teller (GT) modes, and their couplings. It is found that the proposed coupling scheme accounts for a sizable amount of the strength associated with isospin-spin excitations, which include transitions to both one- and two-phonon states. The calculations are performed within the framework of perturbation theory, accounting for the renormalization of the charge by the collective GT excitations.

  10. Development of high-performance alkali-hybrid polarized 3He targets for electron scattering

    NASA Astrophysics Data System (ADS)

    Singh, Jaideep T.; Dolph, P. A. M.; Tobias, W. A.; Averett, T. D.; Kelleher, A.; Mooney, K. E.; Nelyubin, V. V.; Wang, Yunxiao; Zheng, Yuan; Cates, G. D.

    2015-05-01

    Background: Polarized 3He targets have been used as effective polarized neutron targets for electron scattering experiments for over twenty years. Over the last ten years, the effective luminosity of polarized 3He targets based on spin-exchange optical pumping has increased by over an order of magnitude. This has come about because of improvements in commercially-available lasers and an improved understanding of the physics behind the polarization process. Purpose: We present the development of high-performance polarized 3He targets for use in electron scattering experiments. Improvements in the performance of polarized 3He targets, target properties, and operating parameters are documented. Methods: We utilize the technique of alkali-hybrid spin-exchange optical pumping to polarize the 3He targets. Spectrally narrowed diode lasers used for the optical pumping greatly improved the performance. A simulation of the alkali-hybrid spin-exchange optical pumping process was developed to provide guidance in the design of the targets. Data was collected during the characterization of 24 separate glass target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. Results: From the data obtained we made determinations of the so-called X -factors that quantify a temperature-dependent and as-yet poorly understood spin-relaxation mechanism that limits the maximum achievable 3He polarization to well under 100%. The presence of the X -factor spin-relaxation mechanism was clearly evident in our data. Good agreement between the simulation and the actual target performance was obtained by including details such as off-resonant optical pumping. Included in our results is a measurement of the K -3He spin-exchange rate coefficient kseK=(7.46 ±0.62 ) ×10-20cm3/s over the temperature range 503 K to 563 K. Conclusions: In order to achieve high performance under the operating conditions described in this paper

  11. Equilibrium spin pulsars unite neutron star populations

    NASA Astrophysics Data System (ADS)

    Ho, Wynn C. G.; Klus, H.; Coe, M. J.; Andersson, Nils

    2014-02-01

    Many pulsars are formed with a binary companion from which they can accrete matter. Torque exerted by accreting matter can cause the pulsar spin to increase or decrease, and over long times, an equilibrium spin rate is achieved. Application of accretion theory to these systems provides a probe of the pulsar magnetic field. We compare the large number of recent torque measurements of accreting pulsars with a high-mass companion to the standard model for how accretion affects the pulsar spin period. We find that many long spin period (P ≳ 100 s) pulsars must possess either extremely weak (B < 1010 G) or extremely strong (B > 1014 G) magnetic fields. We argue that the strong-field solution is more compelling, in which case these pulsars are near spin equilibrium. Our results provide evidence for a fundamental link between pulsars with the slowest spin periods and strong magnetic fields around high-mass companions and pulsars with the fastest spin periods and weak fields around low-mass companions. The strong magnetic fields also connect our pulsars to magnetars and strong-field isolated radio/X-ray pulsars. The strong field and old age of our sources suggest their magnetic field penetrates into the superconducting core of the neutron star.

  12. Measurement of "pretzelosity" asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized 3He target

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Qian, X.; Allada, K.; Dutta, C.; Huang, J.; Katich, J.; Wang, Y.; Aniol, K.; Annand, J. R. M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M. M.; Deconinck, W.; de Jager, C. W.; De Leo, R.; Deng, X.; Deur, A.; Ding, H.; Dolph, P. A. M.; Dutta, D.; El Fassi, L.; Frullani, S.; Gao, H.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Guo, L.; Hamilton, D.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; Kelleher, A.; Kim, W.; Kolarkar, A.; Korsch, W.; LeRose, J. J.; Li, X.; Li, Y.; Lindgren, R.; Liyanage, N.; Long, E.; Lu, H.-J.; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; McNulty, D.; Meziani, Z.-E.; Michaels, R.; Moffit, B.; Muñoz Camacho, C.; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J. C.; Phillips, S. K.; Posik, M.; Puckett, A. J. R.; Qiang, Y.; Rakhman, A.; Ransome, R. D.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Širca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L.-G.; Tobias, W. A.; Urciuoli, G. M.; Vilardi, I.; Wang, K.; Wojtsekhowski, B.; Yan, X.; Yao, H.; Ye, Y.; Ye, Z.; Yuan, L.; Zhan, X.; Zhang, Y.-W.; Zhao, B.; Zheng, X.; Zhu, L.; Zhu, X.; Zong, X.; Jefferson Lab Hall A Collaboration

    2014-11-01

    An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized 3He target was performed at Jefferson Laboratory in the kinematic region of 0.16 3He, which are expressed as the convolution of the h1T ⊥ transverse-momentum-dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Under the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured 3He asymmetries and cross-section ratios between the proton and 3He. Our results show that both π± on 3He and on neutron pretzelosity asymmetries are consistent with zero within experimental uncertainties.

  13. A New 3He-Target Design for Compton Scattering Experiment

    NASA Astrophysics Data System (ADS)

    Mahalchick, S.; Gao, H.; Laskaris, G.; Weir, W.; Ye, Q.; Ye, Q. J.

    2011-10-01

    The neutron spin polarizabilities describe the stiffness of the neutron spin to external electric and magnetic fields. A double-polarized elastic Compton Scattering experiment will try to determine the neutron spin polarizabilities using a new polarized 3He target and the circularly polarized γ-beam of HI γS facility at the Duke Free Electron Laser Laboratory (DFELL). To polarize the 3He target, a newly constructed solenoid is being used which can provide a very uniform magnetic field around the target area and allows to place High Intensity Gamma Source NaI Detector Arrays (HINDA) closer to the target. The ideal target polarization is 40-60% and will be measured using the nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) techniques. A prototype of the polarized 3He target is being constructed in the Medium Energy Physics Group laboratories at Duke and is currently being tested. The experiment is expected to take place in 2013 after the DFELL upgrade. I will be presenting details of the construction process, including design specifications and data from the magnetic field mapping, as well as preliminary target polarization results. This work is supported by the US Department of Energy, under contract number DE-FG02-03ER41231, and by the National Science Foundation, grant number NSF-PHY-08-51813.

  14. Spin-orbit states of neutron wave packets

    NASA Astrophysics Data System (ADS)

    Nsofini, Joachim; Sarenac, Dusan; Wood, Christopher J.; Cory, David G.; Arif, Muhammad; Clark, Charles W.; Huber, Michael G.; Pushin, Dmitry A.

    2016-07-01

    We propose a method to prepare an entangled spin-orbit state between the spin and the orbital angular momenta of a neutron wave packet. This spin-orbit state is created by passing neutrons through the center of a quadrupole magnetic field, which provides a coupling between the spin and orbital degrees of freedom. A Ramsey-fringe-type measurement is suggested as a means of verifying the spin-orbit correlations.

  15. Comparative study of nuclear effects in polarized electron scattering from 3 He

    DOE PAGESBeta

    Ethier, J. J.; Melnitchouk, W.

    2013-11-01

    We present a detailed analysis of nuclear effects in inclusive electron scattering from polarized 3He nuclei for polarization asymmetries, structure functions and their moments, both in the nucleon resonance and deep-inelastic regions. We compare the results of calculations within the weak binding approximation at finite Q2 with the effective polarization ansatz often used in experimental data analyses, and explore the impact of Δ components in the nuclear wave function and nucleon off-shell corrections on extractions of the free neutron structure. Using the same framework we also make predictions for the Q2 dependence of quasielastic scattering from polarized 3He, data onmore » which can be used to constrain the spin-dependent nuclear smearing functions in 3He.« less

  16. Comparative study of nuclear effects in polarized electron scattering from 3He

    DOE PAGESBeta

    Ethier, Jacob James; Melnitchouk, Wally

    2013-11-04

    We present a detailed analysis of nuclear effects in inclusive electron scattering from polarized 3He nuclei for polarization asymmetries, structure functions and their moments, both in the nucleon resonance and deep-inelastic regions. We compare the results of calculations within the weak binding approximation at finite Q2 with the effective polarization ansatz often used in experimental data analyses, and explore the impact of Δ components in the nuclear wave function and nucleon off-shell corrections on extractions of the free neutron structure. Using the same framework we also make predictions for the Q2 dependence of quasielastic scattering from polarized 3He, data onmore » which can be used to constrain the spin-dependent nuclear smearing functions in 3He.« less

  17. Measurements of the electric form factor of the neutron up to Q2=3.4 GeV2 using the reaction 3He(e,e'n)pp.

    PubMed

    Riordan, S; Abrahamyan, S; Craver, B; Kelleher, A; Kolarkar, A; Miller, J; Cates, G D; Liyanage, N; Wojtsekhowski, B; Acha, A; Allada, K; Anderson, B; Aniol, K A; Annand, J R M; Arrington, J; Averett, T; Beck, A; Bellis, M; Boeglin, W; Breuer, H; Calarco, J R; Camsonne, A; Chen, J P; Chudakov, E; Coman, L; Crowe, B; Cusanno, F; Day, D; Degtyarenko, P; Dolph, P A M; Dutta, C; Ferdi, C; Fernández-Ramírez, C; Feuerbach, R; Fraile, L M; Franklin, G; Frullani, S; Fuchs, S; Garibaldi, F; Gevorgyan, N; Gilman, R; Glamazdin, A; Gomez, J; Grimm, K; Hansen, J-O; Herraiz, J L; Higinbotham, D W; Holmes, R; Holmstrom, T; Howell, D; de Jager, C W; Jiang, X; Jones, M K; Katich, J; Kaufman, L J; Khandaker, M; Kelly, J J; Kiselev, D; Korsch, W; LeRose, J; Lindgren, R; Markowitz, P; Margaziotis, D J; Beck, S May-Tal; Mayilyan, S; McCormick, K; Meziani, Z-E; Michaels, R; Moffit, B; Nanda, S; Nelyubin, V; Ngo, T; Nikolenko, D M; Norum, B; Pentchev, L; Perdrisat, C F; Piasetzky, E; Pomatsalyuk, R; Protopopescu, D; Puckett, A J R; Punjabi, V A; Qian, X; Qiang, Y; Quinn, B; Rachek, I; Ransome, R D; Reimer, P E; Reitz, B; Roche, J; Ron, G; Rondon, O; Rosner, G; Saha, A; Sargsian, M M; Sawatzky, B; Segal, J; Shabestari, M; Shahinyan, A; Shestakov, Yu; Singh, J; Sirca, S; Souder, P; Stepanyan, S; Stibunov, V; Sulkosky, V; Tajima, S; Tobias, W A; Udias, J M; Urciuoli, G M; Vlahovic, B; Voskanyan, H; Wang, K; Wesselmann, F R; Vignote, J R; Wood, S A; Wright, J; Yao, H; Zhu, X

    2010-12-31

    The electric form factor of the neutron was determined from studies of the reaction 3He(e,e'n)pp in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2 range over which it is known, we find G(E)(n)=0.0236±0.0017(stat)±0.0026(syst), 0.0208±0.0024±0.0019, and 0.0147±0.0020±0.0014 for Q(2)=1.72, 2.48, and 3.41 GeV2, respectively. PMID:21231649

  18. The overview and early measurements from the n 3He experiment

    NASA Astrophysics Data System (ADS)

    Garishvili, Garishvili; n3 HE Collaboration

    2015-04-01

    The main goal of the n 3He experiment at the Spallation Neutron Source (SNS) at ORNL is to perform a precise measurement of the parity violating (PV) weak amplitude of the reaction n->+3 He --> T + p + 765 KeV. In particular, the goal is to measure the spatial asymmetry of emitted protons with respect to the neutron spin direction. This asymmetry is expected to be very small (<10-7) since the NN interaction is dominated by the parity conserving (PC) strong amplitude. The final goal is to measure the asymmetry in the n 3He experiment with an accuracy of ~ 2 ×10-8 to isolate the I=0 components of the hadronic weak interaction, which is vital for constraining weak coupling constants predicted by theory. The n 3He detector was installed and commissioned in December 2014 on the Fundamental Neutron Physics Beamline at the SNS. Production data taking is expected to start by the end of January 2015 and planned to run until the end of 2015. The status of the experiment will be presented, including early data.

  19. A Study of 3He detectors for Active Interrogation

    SciTech Connect

    E.H. Seabury; D.L. Chichester

    2009-10-01

    3He proportional counters have long been used as neutron detectors for both passive and active detection of Special Nuclear Material (SNM). The optimal configuration of these detectors as far as gas pressure, amount of moderating material, and size are concerned is highly dependent on what neutron signatures are being used to detect and identify SNM. We present here a parametric study of the neutron capture response of 3He detectors, based on Monte Carlo simulations using the MCNPX radiation transport code. The neutron capture response of the detectors has been modeled as a function of time after an incident neutron pulse.

  20. Polarimetries for the Polarized 3 He Target at JLab

    NASA Astrophysics Data System (ADS)

    Ton, Nguyen; Jefferson Lab Polarized 3 He Target Collaboration

    2015-04-01

    At Jefferson Lab, a Polarized 3 He Target has been used as an effective polarized neutron target for studying nucleon spin structure. For the 12 GeV program at JLab, the first stage upgrade of the target aim to increase luminosity by a factor of 2 (to luminosity ~ 2 ×1036 cm-2s-1) while keep maximum in-beam polarization at 60 % with 30 μA beam current and reach a systematic uncertainty of polarimetry below 3 %. During the 6 GeV era, the target polarization was measured by two polarimetries: adiabatic fast passage-nuclear magnetic resonance (AFP-NMR) and electron paramagnetic resonance (EPR). With the upgrade, a new polarimetry, Pulse-NMR, is being studied in the lab for the up-coming metal coated target. In this talk, we will discuss the detail study of AFP-NMR, EPR, Pulsed-NMR measurements and their corresponding uncertainties.

  1. A Light-Front Approach to the 3He Spectral Function

    NASA Astrophysics Data System (ADS)

    Scopetta, Sergio; Del Dotto, Alessio; Kaptari, Leonid; Pace, Emanuele; Rinaldi, Matteo; Salmè, Giovanni

    2015-09-01

    The analysis of semi-inclusive deep inelastic electron scattering off polarized 3He at finite momentum transfers, aimed at the extraction of the quark transverse-momentum distributions in the neutron, requires the use of a distorted spin-dependent spectral function for 3He, which takes care of the final state interaction effects. This quantity is introduced in the non-relativistic case, and its generalization in a Poincaré covariant framework, in plane wave impulse approximation for the moment being, is outlined. Studying the light-front spin-dependent spectral function for a J = 1/2 system, such as the nucleon, it is found that, within the light-front dynamics with a fixed number of constituents and in the valence approximation, only three of the six leading twist T-even transverse-momentum distributions are independent.

  2. Lattice Waves, Spin Waves, and Neutron Scattering

    DOE R&D Accomplishments Database

    Brockhouse, Bertram N.

    1962-03-01

    Use of neutron inelastic scattering to study the forces between atoms in solids is treated. One-phonon processes and lattice vibrations are discussed, and experiments that verified the existence of the quantum of lattice vibrations, the phonon, are reviewed. Dispersion curves, phonon frequencies and absorption, and models for dispersion calculations are discussed. Experiments on the crystal dynamics of metals are examined. Dispersion curves are presented and analyzed; theory of lattice dynamics is considered; effects of Fermi surfaces on dispersion curves; electron-phonon interactions, electronic structure influence on lattice vibrations, and phonon lifetimes are explored. The dispersion relation of spin waves in crystals and experiments in which dispersion curves for spin waves in Co-Fe alloy and magnons in magnetite were obtained and the reality of the magnon was demonstrated are discussed. (D.C.W)

  3. Neutron-sensitive ZnS/10B2O3 ceramic scintillator detector as an alternative to a 3He-gas-based detector for a plutonium canister assay system

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Ohzu, A.; Toh, K.; Sakasai, K.; Suzuki, H.; Honda, K.; Birumachi, A.; Ebine, M.; Yamagishi, H.; Takase, M.; Haruyama, M.; Kureta, M.; Soyama, K.; Nakamura, H.; Seya, M.

    2014-11-01

    A neutron-sensitive ZnS/10B2O3 ceramic scintillator detector was developed as an alternative to a 3He-gas-based detector for use in a plutonium canister assay system. The detector has a modular structure, with a flat ZnS/10B2O3 ceramic scintillator strip that is installed diagonally inside a light-reflecting aluminium case with a square cross-section, and where the scintillation light is detected using two photomultiplier tubes attached at both ends of the case. The prototype detectors, which have a neutron-sensitive area of 30 mm×250 mm, exhibited a sensitivity of 21.7-23.4±0.1 cps/nv (mean±SD) for thermal neutrons, a 137Cs gamma-ray sensitivity of 1.1-1.9±0.2×10-7 and a count variation of less than 6% over the detector length. A trial experiment revealed a temperature coefficient of less than -0.24±0.05%/°C over the temperature range of 20-50 °C. The detector design and the experimental results are presented.

  4. Nuclear Electric Dipole Moment of 3He

    SciTech Connect

    Stetcu, I; P.Liu, C; Friar, J L; Hayes, A C; Navratil, P

    2008-04-08

    A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of {sup 3}He and the expected sensitivity of such a measurement to the underlying CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {pi}-, {rho}-, and {omega}-exchanges, we find that the pion-exchange contribution dominates. Finally, our results suggest that a measurement of the {sup 3}He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.

  5. Nuclear Electric Dipole Moment of ^{3}_He

    SciTech Connect

    Stetcu, I.; Liu, C.-P.; Friar, J. L.; Hayes, A. C.; Navratil, P.

    2008-01-01

    A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of ^{3}_He and the expected sensitivity of such a measurement to the underlyng CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {\\pi}-, {\\rho}-, and {\\omega}-exchanges, we find that the pion-exchange contribution dominates. Our results suggest that a measurement of the ^{3}_He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.

  6. Spin paramagnetic deformation of a neutron star

    NASA Astrophysics Data System (ADS)

    Suvorov, A. G.; Mastrano, A.; Melatos, A.

    2016-02-01

    Quantum mechanical corrections to the hydromagnetic force balance equation, derived from the microscopic Schrödinger-Pauli theory of quantum plasmas, modify the equilibrium structure and hence the mass quadrupole moment of a neutron star. It is shown here that the dominant effect - spin paramagnetism - is most significant in a magnetar, where one typically has μ _B|B|≳ k_B T_e, where μB is the Bohr magneton, B is the magnetic field, and Te is the electron temperature. The spin paramagnetic deformation of a non-barotropic magnetar with a linked poloidal-toroidal magnetic field is calculated to be up to ˜10 times greater than the deformation caused solely by the Lorentz force. It depends on the degree of Pauli blocking by conduction electrons and the propensity to form magnetic domains, processes which are incompletely modelled at magnetar field strengths. The star becomes more oblate, as the toroidal field component strengthens. The result implies that existing classical predictions underestimate the maximum strength of the gravitational wave signal from rapidly spinning magnetars at birth. Turning the argument around, future gravitational-wave upper limits of increasing sensitivity will place ever-stricter constraints on the physics of Pauli blocking and magnetic domain formation under magnetar conditions.

  7. Single transverse spin asymmetry of forward neutrons

    NASA Astrophysics Data System (ADS)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Iván; Soffer, J.

    2011-12-01

    We calculate the single transverse spin asymmetry AN(t), for inclusive neutron production in pp collisions at forward rapidities relative to the polarized proton in the energy range of RHIC. Absorptive corrections to the pion pole generate a relative phase between the spin-flip and nonflip amplitudes, leading to a transverse spin asymmetry which is found to be far too small to explain the magnitude of AN observed in the PHENIX experiment. A larger contribution, which does not vanish at high energies, comes from the interference of pion and a1-Reggeon exchanges. The unnatural parity of a1 guarantees a substantial phase shift, although the magnitude is strongly suppressed by the smallness of diffractive πp→a1p cross section. We replace the Regge a1 pole by the Regge cut corresponding to the πρ exchange in the 1+S state. The production of such a state, which we treat as an effective pole a, forms a narrow peak in the 3π invariant mass distribution in diffractive πp interactions. The cross section is large, so one can assume that this state saturates the spectral function of the axial current and we can determine its coupling to nucleons via the partially conserved axial-vector-current constraint Goldberger-Treiman relation and the second Weinberg sum rule. The numerical results of the parameter-free calculation of AN are in excellent agreement with the PHENIX data.

  8. Measuring Glass Thickness of a Reference Cell Used in a Polarized 3HE Experiment

    SciTech Connect

    Justis, N.; Chen, J.

    2005-01-01

    Studies of the spin structure of the neutron are often conducted using a polarized 3He target due to its close spin resemblance to that of a free neutron. Experiments are conducted by bombarding polarized 3He nuclei with high-energy electrons from a linear accelerator. The polarized 3He gas is contained in a glass tube-like cell called the target cell. In addition to the target cell, a reference cell is also used for calibration purposes. The thickness of each cell must be accurately determined for the analysis of the scattering data of the experiment. The thickness of a reference cell was determined by using a tunable infrared laser to create a thin-film interference pattern by reflecting the laser light off of the glass cell. The intensity of the pattern is known to vary sinusoidally as the wavelength of the laser changes. Such variation was recorded as an array of numbers by a LabView program at 26 different points on the cell. Each of the 26 sets of data were fit to an equation containing the thickness variable to determine the thickness of the glass. The cell side, or wall, thickness ranged from 1.42 mm to 1.65 mm, with an uncertainty of less than 5% in every case. End, or window, thickness measurements were also successfully taken, but have yet to be fitted to the derived equation.

  9. Neutron Resonance Spin Determination Using Multi-Segmented Detector DANCE

    SciTech Connect

    Baramsai, B.; Mitchell, G. E.; Chyzh, A.; Dashdorj, D.; Walker, C.; Agvaanluvsan, U.; Becvar, F.; Krticka, M.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Keksis, A. L.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.

    2011-06-01

    A sensitive method to determine the spin of neutron resonances is introduced based on the statistical pattern recognition technique. The new method was used to assign the spins of s-wave resonances in {sup 155}Gd. The experimental neutron capture data for these nuclei were measured with the DANCE (Detector for Advanced Neutron Capture Experiment) calorimeter at the Los Alamos Neutron Science Center. The highly segmented calorimeter provided detailed multiplicity distributions of the capture {gamma}-rays. Using this information, the spins of the neutron capture resonances were determined. With these new spin assignments, level spacings are determined separately for s-wave resonances with J{sup {pi}} = 1{sup -} and 2{sup -}.

  10. Early Days of Superfluid ^3He: An Experimenter's View

    NASA Astrophysics Data System (ADS)

    Lee, David

    2010-03-01

    The formulation of the BCS theory led theorists to investigate possible non-S-wave pairing in liquid ^3He. Unfortunately as time went on, estimates for the pairing temperature became unattainably low. Nevertheless, the push to lower temperatures by experimentalists continued and was facilitated by the invention of the dilution refrigerator. Nuclear adiabatic demagnetization could then be used to cool liquid ^3He to ˜1 mK as demonstrated by Goodkind. An alternate approach, suggested by Pomeranchuk, involved adiabatic compression of liquid ^3He into the solid phase. Efforts to develop this technique at the Kapitza Institute, La Jolla and Cornell achieved success in demonstrating cooling of mixtures of liquid and solid ^3He to ˜ 1 mK following dilution refrigerator pre-cooling. Although there was great pessimism regarding the possible observation of pairing in liquid ^3He, the unsettled problem of magnetic ordering in solid ^3He beckoned. Ultimately two phase transition along the melting curve were observed by Osheroff et al at Cornell. Although first associated with solid ^3He, extensive NMR studies showed them to be two new phases of liquid ^3He. A brief history of experiments at various laboratories following the discovery is given, along with early interpretations given by Anderson and Morel and Balian and Werthamer. The key role of Leggett's spin dynamics is also discussed.

  11. Precision Neutron Polarimetry

    NASA Astrophysics Data System (ADS)

    Sharma, Monisha; Barron-Palos, L.; Bowman, J. D.; Chupp, T. E.; Crawford, C.; Danagoulian, A.; Klein, A.; Penttila, S. I.; Salas-Bacci, A. F.; Wilburn, W. S.

    2008-04-01

    Proposed PANDA and abBA experiments aim to measure the correlation coefficients in the polarized neutron beta decay at the SNS. The goal of these experiments is 0.1% measurement which will require neutron polarimetry at 0.1% level. The FnPB neutron beam will be polarized either using a ^3He spin filter or a supermirror polarizer and the neutron polarization will be measured using a ^3He spin filter. Experiment to establish the accuracy to which neutron polarization can be determined using ^3He spin fliters was performed at Los Alamos National Laboratory in Summer 2007 and the analysis is in progress. The details of the experiment and the results will be presented.

  12. Burst Oscillations: A New Spin on Neutron Stars

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod

    2007-01-01

    Observations with NASA's Rossi X-ray Timing Explorer (RXTE) have shown that the X-ray flux during thermonuclear X-ray bursts fr-om accreting neutron stars is often strongly pulsed at frequencies as high as 620 Hz. We now know that these oscillations are produced by spin modulation of the thermonuclear flux from the neutron star surface. In addition to revealing the spin frequency, they provide new ways to probe the properties and physics of accreting neutron stars. I will briefly review our current observational and theoretical understanding of these oscillations and discuss what they are telling us about neutron stars.

  13. On 3He bolometer systems

    NASA Technical Reports Server (NTRS)

    Houck, J. R.

    1983-01-01

    A 3He cryostat which was constructed to cool a germanium bolometer for use as an infrared detector at submillimeter wavelength is discussed. The system had better sensitivity than any other existing system for these wavelengths; the system could be improved if better optical coupling could be achieved between the bolometer and the incoming photon stream. Considerable effort was expended to improve this coupling. Even the best results however, fell short of an ideal system by a factor of nearly 5 in coupling efficiency.

  14. A multipurpose 3He refrigerator

    NASA Astrophysics Data System (ADS)

    Pizzo, L.; Dall'Oglio, G.; Martinis, L.; Sabbatini, L.

    2006-10-01

    We introduce a mini 3He refrigerator, operating at ˜300 mK starting from 4.2 K without pumping on the main 4He bath. The innovative idea is that the present one is suitable for a very fast operation; for its use, it is sufficient a storage 4He Dewar. In this way we drastically reduce the time required to cool it down, because there is no need for a classic cryostat. This prototype is particularly aimed for all those operations in which it is necessary to test a large number of samples that do not require long duration measurements at low temperature.

  15. Ultrasensitive 3He magnetometer for measurements of high magnetic fields

    NASA Astrophysics Data System (ADS)

    Nikiel, Anna; Blümler, Peter; Heil, Werner; Hehn, Manfred; Karpuk, Sergej; Maul, Andreas; Otten, Ernst; Schreiber, Laura M.; Terekhov, Maxim

    2014-11-01

    We describe a 3He magnetometer capable to measure high magnetic fields ( B> 0.1 T) with a relative accuracy of better than 10-12. Our approach is based on the measurement of the free induction decay of gaseous, nuclear spin polarized 3He following a resonant radio frequency pulse excitation. The measurement sensitivity can be attributed to the long coherent spin precession time T2 ∗ being of order minutes which is achieved for spherical sample cells in the regime of "motional narrowing" where the disturbing influence of field inhomogeneities is strongly suppressed. The 3He gas is spin polarized in situ using a new, non-standard variant of the metastability exchange optical pumping. We show that miniaturization helps to increase T2 ∗ further and that the measurement sensitivity is not significantly affected by temporal field fluctuations of order 10-4.

  16. Binary neutron stars with arbitrary spins in numerical relativity

    NASA Astrophysics Data System (ADS)

    Tacik, Nick; Foucart, Francois; Pfeiffer, Harald P.; Haas, Roland; Ossokine, Serguei; Kaplan, Jeff; Muhlberger, Curran; Duez, Matt D.; Kidder, Lawrence E.; Scheel, Mark A.; Szilágyi, Béla

    2015-12-01

    We present a code to construct initial data for binary neutron star systems in which the stars are rotating. Our code, based on a formalism developed by Tichy, allows for arbitrary rotation axes of the neutron stars and is able to achieve rotation rates near rotational breakup. We compute the neutron star angular momentum through quasilocal angular momentum integrals. When constructing irrotational binary neutron stars, we find a very small residual dimensionless spin of ˜2 ×10-4 . Evolutions of rotating neutron star binaries show that the magnitude of the stars' angular momentum is conserved, and that the spin and orbit precession of the stars is well described by post-Newtonian approximation. We demonstrate that orbital eccentricity of the binary neutron stars can be controlled to ˜0.1 % . The neutron stars show quasinormal mode oscillations at an amplitude which increases with the rotation rate of the stars.

  17. Superconducting magnetic Wollaston prism for neutron spin encoding

    SciTech Connect

    Li, F. Parnell, S. R.; Wang, T.; Baxter, D. V.; Hamilton, W. A.; Maranville, B. B.; Semerad, R.; Cremer, J. T.; Pynn, R.

    2014-05-15

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ∼30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ∼98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

  18. Superconducting magnetic Wollaston prism for neutron spin encoding.

    PubMed

    Li, F; Parnell, S R; Hamilton, W A; Maranville, B B; Wang, T; Semerad, R; Baxter, D V; Cremer, J T; Pynn, R

    2014-05-01

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ~30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ~98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed. PMID:24880360

  19. Measurement of the spin-rotation coupling in neutron polarimetry

    NASA Astrophysics Data System (ADS)

    Demirel, Bülent; Sponar, Stephan; Hasegawa, Yuji

    2015-02-01

    The effect of spin-rotation coupling is measured for the first time with neutrons. The coupling of spin with the angular velocity of a rotating spin turner can be observed as a phase shift in a neutron polarimeter set-up. After the neutron’s spin is rotated by 2π through a rotating magnetic field, different phase shifts are induced for ‘up’ and ‘down’ spin eigenstates. This phase difference results in the rotation of the neutron’s spin-vector, which turns out to depend solely on the frequency of the rotation of the magnetic field. The experimental results agree well with the solutions acquired by the Pauli-Schrödinger equation.

  20. Hard Photodisintegration of 3He

    NASA Astrophysics Data System (ADS)

    Granados, Carlos

    2011-02-01

    Large angle photodisintegration of two nucleons from the 3He nucleus is studied within the framework of the hard rescattering model (HRM). In the HRM the incoming photon is absorbed by one nucleon's valence quark that then undergoes a hard rescattering reaction with a valence quark from the second nucleon producing two nucleons emerging at large transverse momentum . Parameter free cross sections for pp and pn break up channels are calculated through the input of experimental cross sections on pp and pn elastic scattering. The calculated cross section for pp breakup and its predicted energy dependency are in good agreement with recent experimental data. Predictions on spectator momentum distributions and helicity transfer are also presented.

  1. Measurements of the Neutron Longitudinal Spin Asymmetry A1n and Flavor Decomposition in the Valence Quark Region

    SciTech Connect

    Flay, David J.

    2014-08-01

    The current data for the nucleon-virtual photon longitudinal spin asymmetry A1 on the proton and neutron have shown that the ratio of the polarized-to-unpolarized down-quarkparton distribution functions,Dd=d, tends towards -1/2 at large x, in disagreement with the perturbative QCD prediction that Dd/d approaches 1 but more in line with constituent quark models. As a part of experiment E06-014 in Hall A of Jefferson Lab, double-spin asymmetries were measured in the scattering of a longitudinally polarized electron beam of energies 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target in the deep inelastic scattering and resonance region, allowing for the extraction of the neutron asymmetry An1 and the ratios Dd/d and Du/u. We will discuss our analysis of the data and present results for A1 and g1/F1 on both 3He and the neutron, and the resulting quark ratios for the up and down quarks in the kinematic range of 0.2

  2. Neutron nano-spin-echo spectrometer based on magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    Aksenov, V. L.; Nikitenko, Yu. V.; Osipov, A. A.

    2007-09-01

    A neutron spin-echo spectrometer based on spin precessors in the form of magnetic layered nanostructures is described. A model of a spin-echo spectrometer is developed on beam no. 9 in the IBR-2 reactor. In this model, spin precession occurs during motion of neutrons in a magnetic field and their double reflection from Al(30 nm)/Fe(15 nm)/Al(120 nm)/Cu(150 nm) magnetic layered structures. The obtained spectrometer parameters make it possible to investigate excitations in films with a wave vector oriented along the neutron beam direction in the range from 10-3 to 10-1 Å-1 and perpendicularly to the beam in the range from 10-4 to 10-5 Å-1.

  3. Measuring Neutron-Star Spins via Burst Oscillations (core Program)

    NASA Astrophysics Data System (ADS)

    Measuring the spin of neutron stars in low-mass X-ray binaries is one of the great strengths and highest priorities for RXTE. We propose targeted observations of known thermonuclear burst sources which do not have confirmed burst oscillations, as well as previously unknown sources, in order to detect new examples of burst oscillations and thus add to the sample of neutron star spins. We will target sources in states of frequent, bright bursts by triggering on the detection of bursts by INTEGRAL and/or Swift. Detection of neutron stars spinning beyond the present maximum will allow us to significantly constrain the neutron-star equation of state, presently an area of major uncertainty.

  4. Larmor labeling of neutron spin using superconducting Wollaston prisms

    NASA Astrophysics Data System (ADS)

    Li, Fankang

    Neutron spin Larmor labeling using magnetic Wollaston prisms (WP) provides a way to overcome some of the limitations arising from the nature of neutron beams: low flux and divergence. Using superconducting films and tapes, a series of strong, well-defined shaped magnetic fields can be produced due to both the zero-resistance and Meissner effect in superconductors. Using finite element simulations, the criterion to build a superconducting magnetic Wollaston prism with high encoding efficiency and low Larmor phase aberrations are presented. To achieve a high magnetic field and simplify the maintenance, we optimize the design using careful thermal analysis. The measured neutron spin flipping efficiency is measured to be independent of both the neutron wavelength and energizing current, which is a significant improvement over other devices with similar functions. A highly linear variation of the Larmor phase is measured across the device, which ensures a highly uniform encoding of scattering angles into the neutron spin Larmor phase. Using two WPs, the correlation function for a colloidal silica sample was measured by spin echo modulated small angle neutron scattering (SEMSANS) and agrees well with other techniques. Using Monte Carlo code (McStas), we further investigated the SEMSANS setup and showed the requirements to improve its performance. We have proposed a new technique to implement neutron spin echo on a triple axis neutron spectrometer to achieve high resolution measurements of the lifetime of dispersive phonon excitations. The spin echo is tuned by appropriate choice of magnetic fields instead of physically tilting the coils used in traditional methods. This new approach allows a higher energy resolution and a larger effective tilting angle and hence larger group velocity to be measured.

  5. NARROW ATOMIC FEATURES FROM RAPIDLY SPINNING NEUTRON STARS

    SciTech Connect

    Bauboeck, Michi; Psaltis, Dimitrios; Oezel, Feryal E-mail: dpsaltis@email.arizona.edu

    2013-04-01

    Neutron stars spinning at moderate rates ({approx}300-600 Hz) become oblate in shape and acquire a nonzero quadrupole moment. In this paper, we calculate the profiles of atomic features from such neutron stars using a ray-tracing algorithm in the Hartle-Thorne approximation. We show that line profiles acquire cores that are much narrower than the widths expected from pure Doppler effects for a large range of observer inclinations. As a result, the effects of both the oblateness and the quadrupole moments of neutron stars need to be taken into account when aiming to measure neutron-star radii from rotationally broadened lines. Moreover, the presence of these narrow cores substantially increases the likelihood of detecting atomic lines from rapidly spinning neutron stars.

  6. 3He Films as Model Strongly Correlated Fermion Systems

    SciTech Connect

    Neumann, Michael; Casey, Andrew; Nyeki, Jan; Cowan, Brian; Saunders, John

    2006-09-07

    Helium films on graphite are atomically layered. This allows a wide variety of studies of strong correlations in two dimensions with density as a continuously tunable parameter. Studies of a monolayer of 3He adsorbed on graphite plated by a bi-layer of HD find a divergence of effective mass with increasing density, corresponding to a Mott-Hubbard transition between a 2D Fermi liquid and a quantum spin liquid phase. While the Fermi liquid survives in 2D, non-Fermi liquid features remain at finite T, recent theories find that this correction arises from the spin component of the backscattering amplitude. In another experiment a 3He film is grown on graphite plated by a bi-layer of 3He. The first 3He layer only solidifies in the presence of an overlayer. However in the regime in which the system comprises a 3He fluid bilayer, we observe a striking maximum in the temperature dependence of both heat capacity and magnetization. This feature is driven towards T = 0 with increasing film coverage, suggestive of a quantum critical point. Well below the maximum a linear temperature dependence of the heat capacity is recovered; the coverage dependence of the effective mass identifies a (bandwidth driven) Mott-Hubbard transition at 9.8 nm-2.

  7. Progress in Polarized 3He Ion Source at RCNP

    SciTech Connect

    Tanaka, M.; Takahashi, Y.; Shimoda, T.; Yasui, S.; Yosoi, M.; Takahisa, K.; Shimakura, N.; Plis, Yu. A.; Donets, E. D.

    2007-06-13

    A long history on the polarized 3He ion source developed at RCNP is presented. We started with an 'OPPIS' (Optical Pumping Polarized Ion Source) and later found the fundamental difficulties in the OPPIS. To overcome them an 'EPPIS' (Electron Pumping Polarized Ion Source) was proposed and its validity was experimentally proven. However, a serious technical disadvantage was also found in the EPPIS. To avoid this disadvantage we proposed a new concept, 'SEPIS' (Spin Exchange Polarized Ion Source), which uses an enhanced spin-exchange cross section theoretically expected at low 3He+ incident energies in the 3He+ + Rb system. Next, we describe the present status of the SEPIS development: construction of a bench test device allowing the measurements of not only the spin-exchange cross sections {sigma}se but also the electron capture cross sections {sigma}ec for the 3He+ + Rb system. The latest experimental data on {sigma}ec are presented and compared with other previous experimental data and the theoretical calculations.Finally, a design study of the SEPIS for practical use in nuclear (cyclotron) and particle physics (synchrotron) is shortly mentioned.

  8. Proposal to measure spin-structure functions and semi-exclusive asymmetries for the proton and neutron at HERA

    SciTech Connect

    Jackson, H.E.; Hansen, J.O.; Jones, C.E.

    1995-08-01

    Nucleon spin physics will be studied in the HERMES experiment, that will use polarized internal targets of essentially pure atomic H, D, and {sup 3}He in the HERA electron storage ring at DESY. A series of measurements of spin-dependent properties of the nucleon and few-body nuclei will be made; the spin structure function g{sub 1}(x) of the proton and neutron will be measured to test the Bjorken sum rule and study the fraction of the nucleon spin carried by quarks; the spin structure function g{sub 2}W, sensitive to quark-gluon correlations, and the structure functions b{sub 1}(x), and {Delta}(x), sensitive to nuclear binding effects, will be measured; and, using the particle identification capability of the HERMES detector, pions will be detected in coincidence with the scattered electrons. The coincident hadron measurements represent the most important extension that can be made at this time to the existing measurements on the nucleon spin structure functions because they provide information about the flavor-dependence of the quark spin distribution in the nucleon. Argonne is providing the Cerenkov counter to be used for particle identification and developing the drifilm coating technique for the ultrathin target cell required for this experiment. The HERMES collaboration intends to use polarized targets with the highest available figures of merit, and the Argonne laser-driven source offers the most promise for a significant advance in present-day targets.

  9. Precise Extraction of the Neutron Magnetic Form Factor from Quasi-elastic 3He(pol)(e(pol),e') at Q^2 = 0.1-0.6 (GeV/c)^2

    SciTech Connect

    Jens-ole Hansen; Brian Anderson; Leonard Auerbach; Todd Averett; William Bertozzi; Tim Black; John Calarco; Lawrence Cardman; Gordon Cates; Zhengwei Chai; Jiang-Ping Chen; Seonho Choi; Eugene Chudakov; Steve Churchwell; G Corrado; Christopher Crawford; Daniel Dale; Alexandre Deur; Pibero Djawotho; Dipangkar Dutta; John Finn; Haiyan Gao; Ronald Gilman; Oleksandr Glamazdin; Charles Glashausser; Walter Gloeckle; Jacek Golak; Javier Gomez; Viktor Gorbenko; F. Hersman; Douglas Higinbotham; Richard Holmes; Calvin Howell; Emlyn Hughes; Thomas Humensky; Sebastien Incerti; Piotr Zolnierczuk; Cornelis De Jager; John Jensen; Xiaodong Jiang; Cathleen Jones; Mark Jones; R Kahl; H Kamada; A Kievsky; Ioannis Kominis; Wolfgang Korsch; Kevin Kramer; Gerfried Kumbartzki; Michael Kuss; Enkeleida Lakuriqi; Meihua Liang; Nilanga Liyanage; John LeRose; Sergey Malov; Demetrius Margaziotis; Jeffery Martin; Kathy McCormick; Robert McKeown; Kevin McIlhany; Zein-Eddine Meziani; Robert Michaels; Greg Miller; Joseph Mitchell; Sirish Nanda; Emanuele Pace; Tina Pavlin; Gerassimos Petratos; Roman Pomatsalyuk; David Pripstein; David Prout; Ronald Ransome; Yves Roblin; Marat Rvachev; Giovanni Salme; Michael Schnee; Charles Seely; Taeksu Shin; Karl Slifer; Paul Souder; Steffen Strauch; Riad Suleiman; Mark Sutter; Bryan Tipton; Luminita Todor; M Viviani; Branislav Vlahovic; John Watson; Claude Williamson; H Witala; Bogdan Wojtsekhowski; Feng Xiong; Wang Xu; Jen-chuan Yeh

    2006-05-05

    We have measured the transverse asymmetry A{sub T'} in the quasi-elastic {sup 3}/rvec He/(/rvec e/,e') process with high precision at Q{sup 2}-values from 0.1 to 0.6 (GeV/c){sup 2}. The neutron magnetic form factor G{sub M}{sup n} was extracted at Q{sup 2}-values of 0.1 and 0.2 (GeV/c){sup 2} using a non-relativistic Faddeev calculation which includes both final-state interactions (FSI) and meson-exchange currents (MEC). Theoretical uncertainties due to the FSI and MEC effects were constrained with a precision measurement of the spin-dependent asymmetry in the threshold region of {sup 3}/rvec He/(/rvec e/,e'). We also extracted the neutron magnetic form factor G{sub M}{sup n} at Q{sup 2}-values of 0.3 to 0.6 (GeV/c){sup 2} based on Plane Wave Impulse Approximation calculations.

  10. Birefringent neutron prisms for spin echo scattering angle measurement

    NASA Astrophysics Data System (ADS)

    Pynn, Roger; Fitzsimmons, M. R.; Lee, W. T.; Stonaha, P.; Shah, V. R.; Washington, A. L.; Kirby, B. J.; Majkrzak, C. F.; Maranville, B. B.

    2009-09-01

    In the first decade of the 19th century, an English chemist, William Wollaston, invented an arrangement of birefringent prisms that splits a beam of light into two spatially separated beams with orthogonal polarizations. We have constructed similar devices for neutrons using triangular cross-section solenoids and employed them for Spin Echo Scattering Angle Measurement (SESAME). A key difference between birefringent neutron prisms and their optical analogues is that it is hard to embed the former in a medium which has absolutely no birefringence because this implies the removal of all magnetic fields. We have overcome this problem by using the symmetry properties of the Wollaston neutron prisms and of the overall spin echo arrangement. These symmetries cause a cancellation of Larmor phase aberrations and provide robust coding of neutron scattering angles with simple equipment.

  11. GRAVITATIONAL WAVES AND THE MAXIMUM SPIN FREQUENCY OF NEUTRON STARS

    SciTech Connect

    Patruno, Alessandro; Haskell, Brynmor; D'Angelo, Caroline

    2012-02-10

    In this paper, we re-examine the idea that gravitational waves are required as a braking mechanism to explain the observed maximum spin frequency of neutron stars. We show that for millisecond X-ray pulsars, the existence of spin equilibrium as set by the disk/magnetosphere interaction is sufficient to explain the observations. We show as well that no clear correlation exists between the neutron star magnetic field B and the X-ray outburst luminosity L{sub X} when considering an enlarged sample size of millisecond X-ray pulsars.

  12. The influence of restricted geometry of diamagnetic nanoporous media on 3He relaxation

    NASA Astrophysics Data System (ADS)

    Alakshin, E. M.; Gazizulin, R. R.; Zakharov, M. Yu.; Klochkov, A. V.; Morozov, E. V.; Salikhov, T. M.; Safin, T. R.; Safiullin, K. R.; Tagirov, M. S.; Shabanova, O. B.

    2015-01-01

    This is an experimental study of the spin kinetics of 3He in contact with diamagnetic samples of inverse opals SiO2, and LaF3 nanopowder. It is demonstrated that the nuclear magnetic relaxation of the absorbed 3He occurs due to the modulation of dipole-dipole interaction by the quantum motion in the two-dimensional film. It is found that the relaxation of liquid 3He occurs through a spin diffusion to the absorption layer, and that the restricted geometry of diamagnetic nanoporous media has an influence on the 3He relaxation.

  13. Light-Front Dynamics and the {{3He}} Spectral Function

    NASA Astrophysics Data System (ADS)

    Pace, Emanuele; Del Dotto, Alessio; Kaptari, Leonid; Rinaldi, Matteo; Salmé, Giovanni; Scopetta, Sergio

    2016-07-01

    Two topics are presented. The first one is a novel approach for a Poincaré covariant description of nuclear dynamics based on light-front Hamiltonian dynamics. The key quantity is the light-front spectral function, where both normalization and momentum sum rule can be satisfied at the same time. Preliminary results are discussed for an initial analysis of the role of relativity in the EMC effect in {{3He}}. A second issue, very challenging, is considered in a non-relativistic framework, namely a distorted spin-dependent spectral function for {{3He}} in order to take care of the final state interaction between the observed pion and the remnant in semi-inclusive deep inelastic electron scattering off polarized {{3He}}. The generalization of the analysis within the light-front dynamics is outlined.

  14. Nuclear electric dipole moment of {sup 3}He

    SciTech Connect

    Stetcu, I.; Friar, J. L.; Hayes, A. C.; Liu, C.-P.; Navratil, P.

    2009-01-28

    In the no-core shell model (NCSM) framework, we calculate the {sup 3}He electric dipole moment (EDM) generated by parity- and time-reversal violation in the nucleon-nucleon interaction. While the results are somehow sensitive to the interaction model chosen for the strong two- and three-body interactions, we demonstrate the pion-exchange dominance to the EDM of {sup 3}He, if the coupling constants for {pi}, {rho} and {omega}-exchanges are of comparable magnitude, as expected. Finally, our results suggest that a measurement of {sup 3}He EDM would be complementary to the currently planned neutron and deuteron experiments, and would constitute a powerful constraint to the models of the pion P- and T-violating interactions.

  15. Precision Polarization of Neutrons

    NASA Astrophysics Data System (ADS)

    Martin, Elise; Barron-Palos, Libertad; Couture, Aaron; Crawford, Christopher; Chupp, Tim; Danagoulian, Areg; Estes, Mary; Hona, Binita; Jones, Gordon; Klein, Andi; Penttila, Seppo; Sharma, Monisha; Wilburn, Scott

    2009-05-01

    Determining polarization of a cold neutron beam to high precision is required for the next generation neutron decay correlation experiments at the SNS, such as the proposed abBA and PANDA experiments. Precision polarimetry measurements were conducted at Los Alamos National Laboratory with the goal of determining the beam polarization to the level of 10-3 or better. The cold neutrons from FP12 were polarized using optically polarized ^3He gas as a spin filter, which has a highly spin-dependent absorption cross section. A second ^ 3He spin filter was used to analyze the neutron polarization after passing through a resonant RF spin rotator. A discussion of the experiment and results will be given.

  16. Tidal Love numbers of a slowly spinning neutron star

    NASA Astrophysics Data System (ADS)

    Pani, Paolo; Gualtieri, Leonardo; Ferrari, Valeria

    2015-12-01

    By extending our recent framework to describe the tidal deformations of a spinning compact object, we compute for the first time the tidal Love numbers of a spinning neutron star to linear order in the angular momentum. The spin of the object introduces couplings between electric and magnetic distortions, and new classes of spin-induced ("rotational") tidal Love numbers emerge. We focus on stationary tidal fields, which induce axisymmetric perturbations. We present the perturbation equations for both electric-led and magnetic-led rotational Love numbers for generic multipoles and explicitly solve them for various tabulated equations of state and for a tidal field with an electric (even parity) and magnetic (odd parity) component with ℓ=2 , 3, 4. For a binary system close to the merger, various components of the tidal field become relevant. In this case we find that an octupolar magnetic tidal field can significantly modify the mass quadrupole moment of a neutron star. Preliminary estimates, assuming a spin parameter χ ≈0.05 , show modifications ≳10 % relative to the static case, at an orbital distance of five stellar radii. Furthermore, the rotational Love numbers as functions of the moment of inertia are much more sensitive to the equation of state than in the static case, where approximate universal relations at the percent level exist. For a neutron-star binary approaching the merger, we estimate that the approximate universality of the induced mass quadrupole moment deteriorates from 1% in the static case to roughly 6% when χ ≈0.05 . Our results suggest that spin-tidal couplings can introduce important corrections to the gravitational waveforms of spinning neutron-star binaries approaching the merger.

  17. Lattice Relaxation of 4He with 3He Impurities: NMR Studies

    NASA Astrophysics Data System (ADS)

    Candela, D.; Huan, C.; Kim, S. S.; Yin, L.; Xia, J. S.; Sullivan, N. S.

    2014-12-01

    Measurements of the 3He nuclear spin relaxation times of dilute 3He impurities in solid 4He have been used to explore the unusual dynamics of solid 4He at low temperatures. The 3He impurities move through the lattice by quantum mechanical exchange with neighboring 4He atoms. Because of the larger zero point motion of the 3He atoms, there is an appreciable lattice distortion that accompanies the tunneling 3 He atom and the tunneling motion depends on the elastic properties of the 4He lattice. This motion modulates the 3He-3He nuclear dipole- dipole interactions and thus determines the NMR relaxation rates. We compare the observed temperature dependence of the NMR relaxation rates with that expected from the measurements of the shear modulus by Syshchenko et al. [Phys. Rev. Lett. 104, 195301 (2009)].

  18. Test of Lorentz Invariance with Spin Precession of Ultracold Neutrons

    SciTech Connect

    Altarev, I.; Gutsmiedl, E.; Baker, C. A.; Iaydjiev, P.; Ivanov, S. N.; Ban, G.; Lefort, T.; Naviliat-Cuncic, O.; Quemener, G.; Bodek, K.; Kistryn, S.; Zejma, J.; Daum, M.; Henneck, R.; Kirch, K.; Knecht, A.; Lauss, B.; Mtchedlishvili, A.; Petzoldt, G.

    2009-08-21

    A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and {sup 199}Hg atoms, is reported. No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field b{sub perpendicular}<2x10{sup -20} eV (95% C.L.). This is the first limit for the free neutron. This result is also interpreted as a direct limit on the gravitational dipole moment of the neutron |g{sub n}|<0.3 eV/c{sup 2} m from a spin-dependent interaction with the Sun. Analyzing the gravitational interaction with the Earth, based on previous data, yields a more stringent limit |g{sub n}|<3x10{sup -4} eV/c{sup 2} m.

  19. Anisotropic Neutron Evaporation from Spinning Fission Fragments

    NASA Astrophysics Data System (ADS)

    Stuttgé, L.; Dorvaux, O.; Gönnenwein, F.; Mutterer, M.; Kopatch, Yu.; Chernysheva, E.; Hanappe, F.; Hambsch, F.-J.

    2011-10-01

    Neutron evaporation anisotropy in the centre of mass of the rotating fission fragments in the spontaneous fission of 252Cf has been investigated within the CORA experiments. If it is well accepted that the bulk of emitted neutrons originate from an isotropic evaporation in the centre of mass of the moving fragments, discrepancies in experimental as well as in theoretical energy and angular distributions appear throughout many attempts performed by various authors. Scission neutrons most probably contribute but don't allow to explain totally the observed anisotropy. Due to its weak contribution to the total anisotropy, the centre of mass anisotropy is very difficult to be highlighted. A novel experimental approach has been developed to extract this effect and will be presented as well as some first results.

  20. DNP for polarizing liquid {sup 3}He

    SciTech Connect

    Uemtasu, H.; Iwata, T.; Kato, S.; Michigami, T.; Ohizumi, S.; Shishido, T.; Tanaka, A.; Toyama, K.; Tajima, Y.; Yoshida, H. Y.; Kuriyama, N.

    2008-02-06

    Using DNP with zeolite powders and TEMPO, we have developed a method to enhance polarization of liquid {sup 3}He. At magnetic field of 2.5 T and a temperature of around 1.5 K, we have obatined polarization enhancement of liquid {sup 3}He, 2.34 and -1.59 for positive and negative enhancements, respectively.

  1. Test of a two-dimensional neutron spin analyzer

    NASA Astrophysics Data System (ADS)

    Falus, Péter; Vorobiev, Alexei; Krist, Thomas

    2006-11-01

    The aim of this measurement was to test the new large-area spin polarization analyzer for the EVA-SERGIS beamline at Institute Laue Langevin (ILL). The spin analyzer, which was built in Berlin selects one of the two spin states of a neutron beam of wavelength 5.5 Å impinging on a horizontal sample and reflected or scattered from the sample. The spin is analyzed for all neutrons scattered into a detector with an area of 190 mm×190 mm positioned 2.7 m behind the sample, thus covering an angular interval of 4°×4°. The tests were done at the HMI V14 beamline followed by tests at the EVA beamline at ILL. The transmission for the two spin components, the flipping ratio and small angle scattering were recorded while scanning the incoming beam on the analyzer. It was clearly visible, that due to the stacked construction the intensity is blocked at regular intervals. Careful inspection shows that the transmission of the good spin component is more than 0.72 for 60% of the detector area and the corrected flipping ratio is more than 47 for 60% of the detector area. Although some small-angle scattering is visible, it is notable that this analyzer design has small scattering intensities.

  2. Spin structure functions of the neutron g{sub 1}{sup n}: SLAC E154 results

    SciTech Connect

    Meziani, Zein-Eddine

    1997-04-20

    We report on a precision measurement of the neutron spin structure function g{sub 1}{sup n} using deep inelastic scattering of polarized electrons by polarized {sup 3}He. For the kinematic range 0.014neutron integral {integral}{sub 0}{sup 1}g{sub 1}{sup n}(x)dx, needed for testing quark-parton model and QCD sum rules.

  3. First result from the magic-PASTIS using large 3He SEOP-polarized GE180 doughnut cell

    NASA Astrophysics Data System (ADS)

    Salhi, Zahir; Babcock, Earl; Gainov, Ramil; Bussmann, Klaus; Kaemmerling, Hans; Pistel, Patrick; Russina, Margarita; Ioffe, Alexander

    2016-04-01

    We report on the first results of the newly proposed and prototyped PASTIS coil set, enabling for XYZ polarization analysis on the future thermal time-of flight spectrometers. Our setup uses a wide-angle banana shaped 3He Neutron Spin Filter cell (NSF) to cover a large range of scattering solid angle. The design assures relative magnetic field gradients < 10-3 cm-1 and large solid angle areas not interrupted by either coils or supports. In the vertical direction nearly 40° are open and the blind spots in the horizontal scattering plane comprise only 3° in 180° due to the square X and Y compensation coils. We present the first results of the field mapping and relaxations time measurements using a large 3He SEOP polarized GE180 doughnut cell.

  4. Enhancement of Magnetization in Liquid 3He at Aerogel Interface

    NASA Astrophysics Data System (ADS)

    Fukui, A.; Kondo, K.; Kato, C.; Obara, K.; Yano, H.; Ishikawa, O.; Hata, T.

    2013-05-01

    A novel feature of condensate state in liquid 3He is predicted theoretically, which consists of spin triplet s-wave Cooper pairs (Higashitani et al. in J. Low. Temp. Phys. 155:83-97, 2009). Such a spin triplet s-wave state will appear inside aerogel near the surface boundary contacting with superfluid 3He-B, and the enhancement of magnetization due to s-wave state is theoretically expected (Nagato et al. in J. Phys. Soc. Jpn. 78:123603, 2009; Higashitani et al. in Phys. Rev. B 85:024524, 2012). In order to detect this proximity effect, we made the interface in columnar glass tube which coated with 2.5 layer 4He, and set a saddle shape NMR coil very near the interface. At 7 bar, we found that superfluidity in liquid 3He inside aerogel never occurred, even at considerably low temperatures. At 24 bar below T/ T c =0.392, we observed no decrease of magnetization with decreasing temperatures. This phenomenon might be due to spin triplet s-wave Cooper pairs.

  5. Eccentric Mergers of Black Holes with Spinning Neutron Stars

    NASA Astrophysics Data System (ADS)

    East, William E.; Paschalidis, Vasileios; Pretorius, Frans

    2015-07-01

    We study dynamical capture binary black hole-neutron star (BH-NS) mergers focusing on the effects of the neutron star spin. These events may arise in dense stellar regions, such as globular clusters, where the majority of neutron stars are expected to be rapidly rotating. We initialize the BH-NS systems with positions and velocities corresponding to marginally unbound Newtonian orbits, and evolve them using general-relativistic hydrodynamical simulations. We find that even moderate spins can significantly increase the amount of mass in unbound material. In some of the more extreme cases, there can be up to a third of a solar mass in unbound matter. Similarly, large amounts of tidally stripped material can remain bound and eventually accrete onto the BH—as much as a tenth of a solar mass in some cases. These simulations demonstrate that it is important to treat neutron star spin in order to make reliable predictions of the gravitational wave and electromagnetic transient signals accompanying these sources.

  6. 3 He Co-magnetometer Readout for the SNS nEDM Experiment

    NASA Astrophysics Data System (ADS)

    Kim, Young Jin; Clayton, Steven

    2014-09-01

    A search for a permanent electric dipole moment (EDM) of the neutron would provide one of the most important low energy tests of the discrete symmetries beyond the Standard Model of particle physics. A new experimental search of neutron EDM, to be conducted at the Spallation Neutron Source (SNS) at ORNL, has been proposed with a goal of 100-fold improvement in the present experimental limit of 10-26e .cm The experiment is based on the magnetic-resonance technique in which polarized neutrons precess at the Larmor frequency when placed in a static magnetic field; a non-zero EDM would be evident as a difference in precession frequency when a strong electric field is applied parallel vs. anti-parallel to the magnetic field. In addition to its role as neutron spin-analyzer via the spin-dependent n+3He nuclear capture process, polarized helium-3 (which has negligible EDM) will serve as co-magnetometer to correct for drifts in the magnetic field. The helium-3 co-magnetometer will be directly read out by superconducting gradiometers coupled to SQUIDs. We describe a proposed SQUID system suitable for the complex neutron EDM apparatus, and demonstrate that the field noise in the SQUID system, tested in an environment similar to the EDM apparatus, meets the nEDM requirement. We also present a test of the compatibility of low-noise SQUID operation with other devices, potential sources of electromagnetic interference, which are necessarily operating during the EDM measurement period and effective ambient magnetic field noise cancellation with an implementation of reference channels.

  7. Measurement of the neutrino-spin correlation parameter B neutron decay using ultracold neutrons

    SciTech Connect

    Wilburn, Wesley S

    2009-01-01

    We present a new approach to measuring the neutrino-spin correlation parameter B in neutron decay. The approach combines the technology of large-area ion-implanted silicon detectors being developed for the abBA experiment, with an ultracold neutron source to provide more precise neutron polarimetry. The technique detects both proton and electron from the neutron decay in coincidence. B is determined from an electron-energy-dependent measurement of the proton spin asymmetry. This approach will provide a statistical precision of 1 x 10-4 . The systematic precision is still being evaluated, but is expected to be below 1 x 10-3 , and could approach 1 x 10-4 . A measurement of B with this precision would place constraints on supersymmetric extensions to the Standard Model.

  8. Relativistic simulations of eccentric binary neutron star mergers: One-arm spiral instability and effects of neutron star spin

    NASA Astrophysics Data System (ADS)

    East, William E.; Paschalidis, Vasileios; Pretorius, Frans; Shapiro, Stuart L.

    2016-01-01

    We perform general-relativistic hydrodynamical simulations of dynamical capture binary neutron star mergers, emphasizing the role played by the neutron star spin. Dynamical capture mergers may take place in globular clusters, as well as other dense stellar systems, where most neutron stars have large spins. We find significant variability in the merger outcome as a function of initial neutron star spin. For cases where the spin is aligned with the orbital angular momentum, the additional centrifugal support in the remnant hypermassive neutron star can prevent the prompt collapse to a black hole, while for antialigned cases the decreased total angular momentum can facilitate the collapse to a black hole. We show that even moderate spins can significantly increase the amount of ejected material, including the amount unbound with velocities greater than half the speed of light, leading to brighter electromagnetic signatures associated with kilonovae and interaction of the ejecta with the interstellar medium. Furthermore, we find that the initial neutron star spin can strongly affect the already rich phenomenology in the postmerger gravitational wave signatures that arise from the oscillation modes of the hypermassive neutron star. In several of our simulations, the resulting hypermassive neutron star develops the one-arm (m =1 ) spiral instability, the most pronounced cases being those with small but non-negligible neutron star spins. For long-lived hypermassive neutron stars, the presence of this instability leads to improved prospects for detecting these events through gravitational waves, and thus may give information about the neutron star equation of state.

  9. Spin observables in neutron-proton elastic scattering

    SciTech Connect

    Ahmidouch, A.; Arnold, J.; van den Brandt, B.; Daum, M.; Demierre, P.; Drevenak, R.; Finger, M. |; Finger, M. Jr.; Franz, J.; Goujon, N.; Hautle, P.; Janout, Z. Jr.; Hajdas, W.; Heer, E.; Hess, R.; Koger, R.; Konter, J.A.; Lacker, H.; Lechanoine-LeLuc, C.; Lehar, F.; Mango, S.; Mascarini, C.; Rapin, D.; Roessle, E.; Schmelzbach, P.A.; Schmitt, H.; Sereni, P.; Slunecka, M.

    1995-07-15

    We describe here two experiments presently running at PSI using the NA2 polarized neutron beam. They are devoted to the measurement of 2- and 3-spin observables in {ital np} elastic scattering for kinetic energies from 230 to 590 MeV with a center of mass angular range from 60 to 180 degrees. The goal is to determine the five {ital NN} scattering amplitudes for isospin 0 in a model independent way. Preliminary results for {ital K}{sub {ital OSKO}} and {ital K}{sub {ital OSSO}} spin-transfers are presented.

  10. The contribution of the {}^3He(γ ,n)pp reaction to the GDH integrand below pion production threshold

    NASA Astrophysics Data System (ADS)

    Laskaris, G.

    2016-03-01

    The first measurements of the three-body phototdisintegration of 3He polarized parallel and anti-parallel to a circularly polarized γ-ray beam were carried out at the High Intensity γ-ray Source (HIγS) facility located at Triangle Universities Nuclear Laboratory (TUNL). A high pressure 3He target, polarized via spin-exchange optical pumping with alkali metals, was used in the experiments. The neutrons from the three-body photodisintegration were detected with sixteen 12.7 cm diameter liquid scintillator detectors. The spin-dependent cross sections and the contributions from the three-body photodisintegration to the 3He Gerasimov-Drell-Hearn sum rule integrand were extracted and compared with state-of-the-art three-body calculations at the incident photon energies of 12.8, 14.7, and 16.5 MeV. The calculations, which include the Coulomb interaction are in good agreement with the results of the measurements at 12.8 and 14.7 MeV but deviate from the results at 16.5 MeV.

  11. A new generation of 3He refrigerators

    NASA Astrophysics Data System (ADS)

    Graziani, A.; DalĺOglio, G.; Martinis, L.; Pizzo, L.; Sabbatini, L.

    2003-12-01

    The characteristics and performance of a new class of 3He refrigerators are discussed. We introduce a 3He refrigerator, which allows a temperature of 296 m K to be reached with a starting point of 4.2 K, without pumping on the main 4He bath. The operating principle is based on the single-expansion helium liquefier: gas cooling by isothermal compression and adiabatic expansion.

  12. A SQUID-based 3He Co-magnetometer Readout for the SNS nEDM Experiment

    NASA Astrophysics Data System (ADS)

    Kim, Young Jin; Clayton, Steven

    2014-03-01

    A discovery of a permanent electric dipole moment (EDM) of the neutron would provide one of the most important low energy tests of the discrete symmetries beyond the Standard Model of particle physics. A new experimental neutron EDM search, to be conducted at the Spallation Neutron Source (SNS) at ORNL, has been proposed to improve the present experimental limit of 10-26 e .cm by two orders of magnitude. The experiment is based on the magnetic-resonance technique in which polarized neutrons precess at the Larmor frequency when placed in a static magnetic field; a non-zero EDM would be evident as a difference in precession frequency when a strong electric field is applied parallel vs. anti-parallel to the magnetic field. In addition to its role as neutron spin-analyzer via the spin-dependent n+3He nuclear capture process, polarized helium-3 (which has negligible EDM) will serve as co-magnetometer to correct for drifts in the magnetic field. The helium-3 magnetization signal will be read out by superconducting gradiometers coupled to SQUIDs. We describe a proposed SQUID system suitable for the complex neutron EDM apparatus, and demonstrate that the field noise in the SQUID system, tested in an environment similar to the EDM apparatus, meets the nEDM requirement.

  13. Measurement of the helium-3 spin structure functions in the resonance region: A test of Quark-Hadron duality on the neutron

    NASA Astrophysics Data System (ADS)

    Solvignon, Patricia H.

    One of the biggest challenges in the study of the nucleon structure is the understanding of the transition from partonic degrees of freedom to hadronic degrees of freedom. In 1970, Bloom and Gilman noticed that structure function data taken at SLAG in the resonance region average to the scaling curve of deep inelastic scattering (DIS). Early theoretical interpretations suggested that these two very different regimes can be linked under the condition that the quark-gluon and quark-quark interactions are suppressed. Substantial efforts are ongoing to investigate this phenomenon both experimentally and theoretically. Quark-hadron duality has been confirmed for the unpolarized structure function F2 of the proton and the deuteron using data from the experimental Hall C at Jefferson Lab (JLab). Indications of duality have been seen for the proton polarized structure function g1 and the virtual photon asymmetry A 1 at JLab Hall B and HERMES. Because of the different resonance behavior, it is expected that the onset of duality for the neutron will happen at lower momentum transfer than for the proton. Now that precise spin structure data in the DIS region are available at large x, data in the resonance region are greatly needed in order to test duality in spin-dependent structure functions. The goal of experiment E01-012 was to provide such data on the neutron (3He) in the moderate momentum transfer (Q 2) region, 1.0 < Q2 < 4.0 (GeV/c) 2, where duality is expected to hold. The experiment ran successfully in early 2003 at Jefferson Lab in Hall A. It was an inclusive measurement of longitudinally polarized electrons scattering from a longitudinally or transversely polarized 3He target. Asymmetries and cross section differences were measured in order to extract the 3He spin structure function g1 and virtual photon asymmetry A1 in the resonance region. A test of quark-hadron duality has then been performed for the 3He and neutron structure functions. The study of spin duality

  14. Lense-Thirring precession around neutron stars with known spin

    NASA Astrophysics Data System (ADS)

    Van Doesburgh, Marieke; van der Klis, Michiel

    2016-07-01

    Quasi periodic oscillations (QPOs) between 300 and 1200 Hz in the X-ray emission from low mass X-ray binaries have been linked to Keplerian orbital motion at the inner edge of accretion disks. Lense-Thirring precession is precession of the line of nodes of inclined orbits with respect to the equatorial plane of a rotating object due to the general relativistic effect of frame dragging. The Lense-Thirring model of Stella and Vietri (1998) explains QPOs observed in neutron star low mass X-ray binaries at frequencies of a few tens of Hz by the nodal precession of the orbits at the inner disk edge at a precession frequency, ν_{LT} , identical to the Lense-Thirring precession of a test particle orbit. A quadratic relation between ν_{LT} and the Keplerian orbital frequency, and a linear dependence on spin frequency are predicted. In early work (van Straaten et al., 2003) this quadratic relation was confirmed to remarkable precision in three objects of uncertain spin. Since the initial work, many neutron star spin frequencies have been measured in X-ray sources that show QPOs at both low and high frequency. Using archival data from the Rossi X-ray Timing Explorer, we compare the Lense-Thirring prediction to the properties of quasi periodic oscillations measured in a sample of 14 low mass X-ray binaries of which the neutron star spin frequencies can be inferred from their bursting behaviour. We find that in the range predicted for the precession frequency, we can distinguish two different oscillations that often occur simultaneously. In previous works, these two oscillations have often been confused. For both frequencies, we find correlations with inferred Keplerian frequency characterized by power laws with indices that differ significantly from the prediction of 2.0 and therefore inconsistent with the Lense-Thirring model. Also, the specific moment of inertia of the neutron star required by the observed frequencies exceeds values predicted for realistic equations of

  15. Simulation of detector signals in n+3 He --> p + t

    NASA Astrophysics Data System (ADS)

    Coppola, Christopher; n3He Collaboration

    2015-10-01

    The parity violating proton directional asymmetry from the capture of polarized neutrons on 3He is being measured with a pulsed neutron beam at the Spallation Neutron Source at Oak Ridge National Laboratory. The target is an ion chamber with 3He at approximately half an atmosphere. Signal wires at different locations in the chamber have different sensitivities to the physics asymmetry, which are determined by the geometry and configuration of the experiment. These geometry factors must be determined by simulation. In addition, a simulation can estimate the statistical precision of the experiment, optimize configuration variables, and assist with error analysis. To achieve the most accurate simulation of the detector signals, a custom simulation was written in C++ using weighted variables and taking advantage of parallel execution. The inputs used to construct the simulation came from measurements of the neutron phase space, ENDF cross sections, and PSTAR ionization data. A cell model was used to combine this physics to produce an accurate simulation of the experimental data. This simulation can be used to calculate accurate and tunable geometry factors, and to produce desired quanities for use in optimization and analysis.

  16. Hexapole magnet system for thermal energy 3He atom manipulation

    NASA Astrophysics Data System (ADS)

    Jardine, A. P.; Fouquet, P.; Ellis, J.; Allison, W.

    2001-10-01

    We present design and construction details for a novel high field, small bore permanent hexapole magnet. The design is intended for focusing atomic beams of 3He at thermal energies. The magnet uses an optimized polepiece design which includes vacuum gaps to enable its use with high intensity atomic and molecular beams. The 0.3 m long, 1 mm internal radius magnet achieves a polepiece tip field of 1.1 T using NdFeB permanent magnets and Permendur 49 polepieces. The polepiece shanks are designed to saturate so that the hexapole properties are determined predominantly by the shape of the polepiece tip. The performance of the hexapole assembly is demonstrated with an 8 meV 3He beam in the beam source of the Cambridge spin echo spectrometer and the measured focused beam results show excellent agreement with theoretical predictions and negligible beam attenuation.

  17. Zircon 4He/3He thermochronometry

    NASA Astrophysics Data System (ADS)

    Tripathy-Lang, Alka; Fox, Matthew; Shuster, David L.

    2015-10-01

    Multiple thermochronometric methods are often required to constrain time-continuous rock exhumation for studying tectonic processes or development of km-scale topography at Earth's surface. Here, we explore 4He/3He thermochronometry of zircon as a method for constraining continuous time-temperature (t-T) paths of individual samples through a temperature range that is complementary to methods such as 40Ar/39Ar thermochronometry of K-feldspar and 4He/3He thermochronometry of apatite. For different cooling rates and diffusion domain size, the temperature sensitivity of zircon 4He/3He thermochronometry ranges from slightly less than 100 °C to slightly greater than 250 °C; a typical sample provides continuous thermal constraints over ∼100 °C within that range. Outside these temperatures, 4He in zircon will either be quantitatively retained or completely lost by volume diffusion. As proof-of-concept, we present stepwise release 4He/3He spectra and associated U and Th concentration maps measured by laser ablation ICP-MS analysis of individual crystal aliquots of Fish Canyon Tuff (FCT) zircon and of a more complex setting in the Sierra Nevada batholith that experienced reheating from a proximal basaltic intrusion, the Little Devil's Postpile (LDP). The FCT zircon 4He/3He release spectra are consistent with a 4He spatial distribution dominated by alpha-ejection from crystal surfaces. The spatial distributions of U and Th measured in the same crystals do not substantially influence 4He/3He release spectra that are predicted for the known thermal history, even when incorporating spatially variable diffusivity due to accumulation of radiation damage. Conversely, the LDP 4He/3He release spectra are strongly influenced by the observed parent nuclide zonation. A three-dimensional (3D) numerical model of 4He production and diffusion, which incorporates crystal geometry, U and Th zonation, and spatially variable He diffusion kinetics, substantially improves the fit between

  18. A Study of Hadronic Weak Interaction - The n3He Experiment at SNS

    NASA Astrophysics Data System (ADS)

    Kabir, Latiful

    2015-10-01

    While parity violation (PV) is well-understood at the quark and lepton level, it is much more elusive in hadronic systems, being dominated by several orders of magnitude by the strong interaction. However, studies of PV in hadronic systems offer a unique probe of nucleon structure, complementary to other probes of low-energy non-perturbative QCD. The n3He experiment at the spallation neutron source at ORNL is motivated to probe the Hadronic Weak Interaction (HWI) by measuring the parity violating spin asymmetry of the recoil proton in the reaction n + 3He --> p +T +765 KeV. This is sensitive to ΔI = 0 and 1 components of the HWI, and is expected to be extremely small (of the order of 10-7). The experiment aims to determine this PV asymmetry with the statistical sensitivity of the order of 10-8. The experiment is now in the data taking phase and will continue until the end of the year. I will describe the experiment and give its current status.

  19. Neutron Spin Structure Measurements in JLab Hall A

    SciTech Connect

    J.P. Chen

    2004-09-01

    Recent progress from Jefferson Lab has significantly improved our understanding of the nucleon spin structure in the high-x region. Results from two experiments in Hall A are presented. The first experiment is a precision measurement of the neutron spin asymmetry, A{sub 1}{sup n}, in the high-x (valence quark) region. The results show for the first time that A{sub 1}{sup n} becomes positive at large x, strongly breaking SU(6) (spin-flavor) symmetry. The data trend is in good agreement with SU(6)-breaking valence quark models and with the fits to the previous world data. Combining the A{sub 1}{sup n} results with the world A{sub 1}{sup n} data, the up and down quark spin distributions in the nucleon were extracted. The results showed that for the proton the valence down quark spin is in the opposite direction from that of the proton, in disagreement with predictions of leading-order perturbative QCD models, which neglect quark orbital angular momentum.

  20. Transport in ultradilute solutions of 3He in superfluid 4He

    NASA Astrophysics Data System (ADS)

    Baym, Gordon; Beck, D. H.; Pethick, C. J.

    2015-07-01

    We calculate the effect of a heat current on transporting 3He dissolved in superfluid 4He at ultralow concentration, as will be utilized in a proposed experimental search for the electric dipole moment of the neutron (nEDM). In this experiment, a phonon wind will be generated to drive (partly depolarized) 3He down a long pipe. In the regime of 3He concentrations ≲10-9 and temperatures ˜0.5 K, the phonons comprising the heat current are kept in a flowing local equilibrium by small angle phonon-phonon scattering, while they transfer momentum to the walls via the 4He first viscosity. On the other hand, the phonon wind drives the 3He out of local equilibrium via phonon-3He scattering. For temperatures below 0.5 K, both the phonon and 3He mean free paths can reach the centimeter scale, and we calculate the effects on the transport coefficients. We derive the relevant transport coefficients, the phonon thermal conductivity, and the 3He diffusion constants from the Boltzmann equation. We calculate the effect of scattering from the walls of the pipe and show that it may be characterized by the average distance from points inside the pipe to the walls. The temporal evolution of the spatial distribution of the 3He atoms is determined by the time dependent 3He diffusion equation, which describes the competition between advection by the phonon wind and 3He diffusion. As a consequence of the thermal diffusivity being small compared with the 3He diffusivity, the scale height of the final 3He distribution is much smaller than that of the temperature gradient. We present exact solutions of the time dependent temperature and 3He distributions in terms of a complete set of normal modes.

  1. Polarization of3He and3He-4He mixtures with the castaing-nozieres method

    NASA Astrophysics Data System (ADS)

    van Woerkens, C. M. C. M.; Remeijer, P.; Steel, S. C.; Jochemsen, R.; Frossati, G.

    1996-01-01

    We describe experiments employing a strongly improved technique to prepare highly polarized3He and3He-4He mixtures. The polarization is obtained with the rapid melting method. A novel design cell using Vespel SP-1 (a sintered form of polyimide) can reach relative volume changes of 17%, which is required to decompress a completely solid3He-4He mixture to a completely liquid state at 23 bar.

  2. Photoproduction of eta-mesic 3He.

    PubMed

    Pfeiffer, M; Ahrens, J; Annand, J R M; Beck, R; Caselotti, G; Cherepnya, S; Föhl, K; Fog, L S; Hornidge, D; Janssen, S; Kashevarov, V; Kondratiev, R; Kotulla, M; Krusche, B; McGeorge, J C; MacGregor, I J D; Mengel, K; Messchendorp, J G; Metag, V; Novotny, R; Rost, M; Sack, S; Sanderson, R; Schadmand, S; Thomas, A; Watts, D P

    2004-06-25

    The photoproduction of eta-mesic 3He has been investigated using the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI. The total inclusive cross section for the reaction gamma3He-->etaX has been measured for photon energies from threshold to 820 MeV. The total and angular differential coherent eta cross sections have been extracted up to energies of 745 MeV. A resonancelike structure just above the eta production threshold with an isotropic angular distribution suggests the existence of a resonant quasibound state. This is supported by studies of a competing decay channel of such a quasibound eta-mesic nucleus into pi(0)pX. A binding energy of (-4.4+/-4.2) MeV and a width of (25.6+/-6.1) MeV is deduced for the quasibound eta-mesic state in 3He. PMID:15244998

  3. Hyperfine structure of /sup 3/He

    SciTech Connect

    Druzbick, J.; Williams, H.T.

    1987-01-01

    Relativistic contribution to the hyperfine structure of /sup 3/He are reexamined in order to resolve inconsistencies in published values. The orbit-orbit and diamagnetic screening contributions are recomputed and are found to contribute less than one part per million (ppm), contrary to previous results. A new value (318 ppm compared to the perturbation result of 327 ppm) is obtained for the relativistic velocity correction using recently available relativistic Hartree-Fock wave functions. New values of the hyperfine-structure splitting of /sup 3/He in the 1S2S state and the /sup 3/He ion in the 1S and 2S states are presented. Comparison with experiment suggests that the relativistic velocity correction should be 323 ppm and the nuclear structure correction should be 184.2 ppm.

  4. Coherent Photoproduction of pi^+ from 3/^He

    SciTech Connect

    Rakhsha Nasseripour, Barry Berman

    2011-03-01

    We have measured the differential cross section for the $\\gamma$$^3$He$\\rightarrow \\pi^+ t$ reaction. This reaction was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall-B bremsstrahlung tagging system in the energy range from 0.50 to 1.55 GeV were incident on a cryogenic liquid $^3$He target. The differential cross sections for the $\\gamma$$^3$He$\\rightarrow \\pi^+ t$ reaction were measured as a function of photon-beam energy and pion-scattering angle. Theoretical predictions to date cannot explain the large cross sections except at backward angles, showing that additional components must be added to the model.

  5. Event identification in 3He proportional counters using risetime discrimination

    NASA Astrophysics Data System (ADS)

    Langford, T. J.; Bass, C. D.; Beise, E. J.; Breuer, H.; Erwin, D. K.; Heimbach, C. R.; Nico, J. S.

    2013-07-01

    We present a straightforward method for particle identification and background rejection in 3He proportional counters for use in neutron detection. By measuring the risetime and pulse height of the preamplifier signals, one may define a region in the risetime versus pulse height space where the events are predominately from neutron interactions. For six proportional counters surveyed in a low-background environment, we demonstrate the ability to reject alpha-particle events with an efficiency of 99%. By applying the same method, we also show an effective rejection of microdischarge noise events that, when passed through a shaping amplifier, are indistinguishable from physical events in the counters. The primary application of this method is in measurements where the signal-to-background for counting neutrons is very low, such as in underground laboratories.

  6. APT {sup 3}He target/blanket. Topical report

    SciTech Connect

    1995-03-01

    The {sup 3}He target/blanket (T/B) preconceptual design for the 3/8-Goal facility is based on a 1000-MeV, 200-mA accelerator to produce a high-intensity proton beam that is expanded and then strikes one of two T/B modules. Each module consists of a centralized neutron source made of tungsten and lead, a proton beam backstop region made of zirconium and lead, and a moderator made of D{sub 2}O. Helium-3 gas is circulated through the neutron source region and the blanket to create tritium through neutron capture. The gas is continually processed to extract the tritium with an online separation process.

  7. Measurement of the generalized forward spin polarizabilities of the neutron

    SciTech Connect

    Moskov Amarian; Leonard Auerbach; Todd Averett; J. Berthot; Pierre Bertin; William Bertozzi; Tim Black; Edward Brash; David Brown; Etienne Burtin; John Calarco; Gordon Cates; Zhengwei Chai; Jian-Ping Chen; Seonho Choi; Eugene Chudakov; Evaristo Cisbani; Cornelis de Jager; Alexandre Deur; Rachele Di Salvo; Sonja Dieterich; Pibero Djawotho; John Finn; Kevin Fissum

    2004-05-01

    The generalized forward spin polarizabilities {gamma}{sub 0} and {delta}{sub LT} of the neutron have been extracted for the first time in a Q{sup 2} range from 0.1 to 0.9 GeV{sup 2}. Since {gamma}{sub 0} is sensitive to nucleon resonances and {delta}{sub LT} is insensitive to the {Delta} resonance, it is expected that the pair of forward spin polarizabilities should provide benchmark tests of the current understanding of the chiral dynamics of QCD. The new results on {delta}{sub LT} show significant disagreement with Chiral Perturbation Theory calculations, while the data for {gamma}{sub 0} at low Q{sup 2} are in good agreement with a next-to-lead order Relativistic Baryon Chiral Perturbation theory calculation. The data show good agreement with the phenomenological MAID model.

  8. High-momentum response of liquid 3He.

    PubMed

    Mazzanti, F; Polls, A; Boronat, J; Casulleras, J

    2004-02-27

    A final-state-effects formalism suitable to analyze the high-momentum response of Fermi liquids is presented and used to study the dynamic structure function of liquid 3He. The theory, developed as a natural extension of the Gersch-Rodriguez formalism, incorporates the Fermi statistics explicitly through a new additive term which depends on the semidiagonal two-body density matrix. The use of a realistic momentum distribution, calculated using the diffusion Monte Carlo method, and the inclusion of this additive correction allows for good agreement with available deep-inelastic neutron scattering data. PMID:14995785

  9. Hard Photodisintegration of Proton Pairs in {sup 3}He

    SciTech Connect

    Piasetzky, Eli; Pomerantz, Ishay; Higinbotham, D.; Strauch, S.; Gilman, R.

    2008-10-13

    Hard deuteron photodisintegration has been investigated for 20 years, as its cross section follows the constituent counting rule and it provides insight into the interplay between hadronic and quark-gluon degrees of freedom in high-momentum transfer exclusive reactions. We have now measured for the first time hard pp-pair disintegration in the reaction {gamma}{sup 3}He{yields}pp+n, using kinematics corresponding to a spectator neutron. Cross sections were measured for 90 deg. c.m. at 8 beam energies, from 0.8 to 4.7 GeV. Preliminary results will be presented and compared to the hard deuteron photodisintegration data.

  10. Noise Studies of Polarimetry Systems for Polarized 3 He Targets

    NASA Astrophysics Data System (ADS)

    Katugampola, Sumudu K.; Matyas, Daniel J.; Nelyubin, Vladimir; Wang, Yunxiao; Cates, Gordon D.

    2015-04-01

    The NMR technique of adiabatic fast passage (AFP) plays an important role in 3 He targets polarized using spin-exchange optical pumping. Since AFP signals before amplification are generally small, identifying these signals amidst noise caused by external electromagnetic interference and micro-phonics can be challenging. When using thermally polarized water samples for absolute calibration of AFP signals, electromagnetic and micro-phonic noise can easily dominate. Although both types of interference have often been cited as the predominant sources of noise during AFP, few studies of these effects have been done under the conditions that are typical for a polarized 3 He target. This talk will describe studies of electromagnetic and micro-phonic noise using a small-scale prototype NMR system similar to those we use to study polarized 3 He targets. We will describe the effect of using aluminum metal shielding and other methods to minimize noise. We are using these studies to inform the design of a full-scale set up that will be used to test next-generation targets for use at Jefferson Lab, and measure atomic parameters relevant to polarimetry.