Spin echo small angle neutron scattering using a continuously pumped 3He neutron polarisation analyser

Abstract

We present a new instrument for spin echo small angle neutron scattering (SESANS) developed at the Low Energy Neutron Source (LENS) 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 wavelength range of neutron wavelengths. Neutron polarisation analysis is accomplished using a continuously-operating neutron spin filter polarised by Rb-spin exchange optical pumping of 3 He. We describe the performance of the analyser along with a study of the 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.

Different agglomeration properties of PC61BM and PC71BM in photovoltaic inks – a spin-echo SANS study

“…For each SESANS measurement, we plot the 'normalised SESANS signal'. 70,71 Qualitatively this can be interpreted as a correlation function G(z) related to a Debye type correlation function. At long spin-echo lengths G(z / N) the value of this normalised spin-echo signal is given by S t and this can be converted directly to a volume fraction when scattering is observed.…”

Optically polarizedHe3

“…An in-situ NSF has been operated routinely on the Magnetism Reflectometer at the SNS 21 (Tong et al , 2012) and smaller in-situ systems have been developed for the HB3 triple-axis spectrometer and the hybrid spectrometer (HYSPEC) at the SNS (Jiang et al , 2014). At LENS 22 , a continuously pumped analyzer has been demonstrated for spin echo small angle neutron scattering (SESANS) (Parnell et al , 2015). Compact NSFs with low loss AFP NMR for on-beam operation have been developed at KEK 23 (Ino et al , 2012, 2005).…”

Compact spherical neutron polarimeter using high-Tc YBCO films

“…The SESAME beamline 33 provides a pulsed, polarized neutron beam with wavelengths in the range from 2 to 10 Å and polarization up to 92%. The neutrons are polarized using a supermirror bender 32 and the polarization is analysed using a continuously pumped 3 He filter.…”