Conveners
Polarized Neutrons
- Fankang Li (Oak Ridge National Lab)
Polarized Neutrons
- Fankang Li (Oak Ridge National Lab)
Polarized Neutrons
- Chenyang Jiang (ORNL)
Spherical Neutron Polarimetry (SNP) analyzes complex magnetic structures through distinguishing contributions from nuclear-magnetic interference and chiral structure in addition to nuclear magnetic scattering separation. This analysis is achieved through determining all components in the polarization transfer process. Currently, wide-angle SNP is being realized at Oak Ridge National Laboratory...
Spherical neutron polarimetry (SNP) is a powerful neutron scattering technique that can unambiguously determine complex types of magnetic order in materials such as chiral antiferromagnets, multiferroics, superconductors, and magnetoelectrics. Currently, four polarimeter designs exist worldwide and several instruments operate year round that utilize them. Of the three existing SNP designs, two...
Polarized neutron experiment probes magnetic structures and distinguish contribution from incoherent scattering, nuclear scattering and magnetic scattering1. While polarized neutron measurement are widely used among current neutron beamlines, the applications are usually limited to depolarization measurement among a single direction. More complexed polarimetry technique such as xyz...
The aCORN experiment measured the electron-antineutrino angular correlation coefficient (the ‘a’ coefficient) in free neutron decay on the NG-C neutron beam at the National Institute of Standards and Technology (NIST). Though the NIST neutron beams are expected to be unpolarized, an earlier run of the experiment found a small polarization on the NG-6 beamline. The aCORN measurement is quite...
Understanding the interactions leading to magnetic quantum phenomena in a wide range of quantum materials is important for development of new quantum materials and future technologies. Quantifying these interactions and the resultant magnetic matter in quantum materials that exhibit exotic matter such as quantum spin liquids, topological insulators, and Weyl semimetals, is currently being...
Nuclear spin-polarized 3He is widely used in many scientific areas. One of the applications is used as a neutron spin filter to polarize neutrons. Among all the neutron polarizing techniques, nuclear-spin-polarized 3He neutron spin filters have shown great flexibility and versatility because of its highly spin-dependent neutron absorption cross section, large neutron acceptance angle and...
3He has a strong spin-dependent neutron absorption cross section and polarized 3He gas by optical pumping can be employed to effectively polarize and spin-analyze large area, widely divergent, and broadband neutron beams. The adiabatic fast passage (AFP) nuclear magnetic resonance (NMR) technique allows to invert the 3He nuclear polarization, hence the neutron polarization. These unique...
As a neutron scatters from a target nucleus, there is a small but measurable effect caused by the interaction of the neutron's magnetic dipole moment with that of the partially screened electric field of the nucleus. This spin-orbit interaction is typically referred to as Schwinger scattering [1] and induces a small rotation of the neutron's spin on the order of 10$^{-4}$ rad for Bragg...
Despite the challenges, neutron resonance spin echo (NRSE) still holds the promise to improve upon neutron spin echo (NSE) for measurement of slow dynamics in materials. In particular, the modulated intensity with zero effort (MIEZE) configuration allows for the measurement of depolarizing samples and is naturally suited for combination with small angle neutron scattering (SANS) as a result of...
Polarized neutron scattering is a powerful tool to study from materials to fundamental physics,and polarized $^3$He gas is now playing an important role at high flux neutron sources as neutron spin filters (NSF). At the spallation neutron source in J-PARC (Japan Proton Accelerator Research Complex), a polarized inelastic neutron spectrometer, POLANO, is now under commissioning, and an...
Polarized neutron techniques have been widely developed and integrated into many instruments at major neutron sources around the world. At the China Spallation Neutron Source (CSNS), the polarized neutron and sample environment groups are developing a complete system to support the ongoing beamline design and construction efforts. In this presentation, we will introduce the current development...
In-situ polarization can provide the highest performance over time for polarized $^3$He over time where $^3$He polarizations in excess of 80% can be maintained. The polarization rates and magnitude achieved are aided by using high performance $^3$He cells produced all in house and techniques such as hybrid spin-exchange optical pumping and chipped volume Bragg grating narrowed laser diode...
The Neutron OPtics Time Reversal Experiment (NOPTREX) collaboration is working towards a sensitive search for time reversal violation in polarized neutron transmission through polarized heavy nuclei. The experiment requires an intense, stable polarized neutron beam at the resonance energies of interest near 1 eV. We have recently constructed a $^3$He neutron spin filter at Indiana University...
