In situ SEOP polarised 3He neutron spin filter for incident beam polarisation and polarisation analysis on neutron scattering instruments

Boag, S.; Babcock, Earl; Andersen, K.H.; Becker, M.; Charlton, Timothy; Chen, Wangchun; Dalgliesh, R. M.; Elmore, S.; Frost, C. D.; Gentile, Thomas R.; Antón, Ricardo López; Parnell, Steven R.; Petoukhov, A.; Skoda, Maximilian W. A.; Söldner, T.

doi:10.1016/j.physb.2009.06.039

Cited by 36 publications

(9 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was narrowed using a holographic grating (2400 lines/mm) (Edmund optics, USA). In addition, a beam splitter was placed in the cavity to limit the emission to the grating; this design is similar to that used to achieve high polarisation of 3 He [26,28].…”

Section: Methodsmentioning

confidence: 99%

Enhancement of X129e polarization by off-resonant spin exchange optical pumping

Parnell

Deppe

Parra‐Robles

et al. 2010

Journal of Applied Physics

View full text Add to dashboard Cite

A high power narrow line width (38W, 0.09nm FWHM) external cavity diode laser is investigated for rubidium spin exchange optical pumping of 129 Xe. This tunable photon source has a constant line width, independent of operating power or wavelength within a 1 nm tuning range. When using this laser, an increase in the 129 Xe nuclear polarisation is observed when optically pumping at a lower wavelength than the measured Rb electron D 1 absorption. The exact detuning from D 1 for the highest polarisation is dependent upon the gas density. Furthermore, at high power and/or high Rb density, a reduction of the polarisation occurs at the optimum wavelength as previously reported in SEOP studies of 3 He which is consistent with high absorption close to the cell front face. These results are encouraging for moderate high throughput polarisation of 129 Xe in the mid pressure range of (0.5-2.0 amg). * Electronic address: S.R.Parnell@Sheffield.ac.uk † Electronic address: J.M. Wild@Sheffield.ac.uk

show abstract

Section: Methodsmentioning

confidence: 99%

Enhancement of X129e polarization by off-resonant spin exchange optical pumping

Parnell

Deppe

Parra‐Robles

et al. 2010

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The change of 3 He polarisation in turn effects the performance of the beamline as a whole, as the device has a time dependent analysing power. This can be overcome by continuously pumping during measurements [24][25][26]. Finally, the scattered beam is detected using an array of 1/2" diameter 1-D position sensitive 3 He detector tubes.…”

Section: Instrument Descriptionmentioning

confidence: 99%

“…The flat windows are intended to reduce any lensing and birefringent effects which can occur in cells from re-blown glass. This is critical in our application as the cell cannot be side pumped as in similar online pumping experiments [25]. The windows are 8 mm thick and the cell body is 80 mm long with an inner diameter of 60 mm.…”

Section: He Analysermentioning

confidence: 99%

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

Parnell

Washington

et al. 2015

Review of Scientific Instruments

View full text Add to dashboard Cite

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.

show abstract

“…1) to control the feedback to the laser. 31 The main beam was reflected by the beamsplitter cube while a weaker beam was transmitted to the diffraction grating. The optic axis of the half-wave plate was typically adjusted to rotate the linear polarization of the laser light by between 258 and 308 relative to the minimum feedback condition.…”

Section: Apparatusmentioning

confidence: 99%

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

Chen

Gentile

et al. 2014

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

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 P He . We also report a comparable improvement in P 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 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 He is increased alkali-metal polarization. We have observed P He of between 0.80 and 0.85 in several large cells, which marks a new precedent for the polarization achievable by SEOP. V C 2014 AIP Publishing LLC. [http://dx.

show abstract

In situ SEOP polarised 3He neutron spin filter for incident beam polarisation and polarisation analysis on neutron scattering instruments

Cited by 36 publications

References 18 publications

Enhancement of X129e polarization by off-resonant spin exchange optical pumping

Enhancement of X129e polarization by off-resonant spin exchange optical pumping

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

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

Contact Info

Product

Resources

About