（Project use）

Experimental Report
Project No.
2014P0803
Title of experiment
Development and application of on-beam SEOP based 3He spin
filter at BL15
Name of principal investigator
Takayuki OKU
Affiliation
J-PARC Center

1. Outline of experimental method and results.

Date of Approval 2016/1/18
Approver Jun-ichi Suzuki
Date of Report 2016/1/18
Name of instrument scientist
Jun-ichi Suzuki
Name of Instrument/（BL No.）
TAIKAN / BL15
Date(s) of experiment(s)2014/05/21-2014/05/23(Experimental method and results should be reported including

sample information such as composition, physical and/or chemical characteristics.)
We performed polarized small-angle neutron
scattering demonstration experiments on silver
behenate (C22H43AgO2). In this study, we aim
to separate coherent and incoherent neutron
scattering components from silver behenate byusing polarized 3He gas as a neutron spin
analyzer.
experiments

Schematicisshowndrawingof

thein1.

TheFig.

polarization analysis set up consists of asupermirror based neutron spin polarizer, aneutron spin flipper, a sample area, a polarized
3He gas analyzer with a magnetic environment

device and 2D detector bank. The size of the3He cell was 35 mm in diameter and 55 mm inlength. The pressure length-product of the cellwas 11 amg・cm. The distance between thesample and the polarized 3He cell was almost
10 mm. So the 3He cell analyzer had aFig.1 Schematic drawing of experimental setup.

coverage angle of 26 degree.Considering thepresent geometry, the small angle detectorbank must be fully covered by the3Heanalyzer.
The 3He gas was polarized by using spin-exchange optical pumping (SEOP) station and then brought into thebeamline. The nuclei polarization of the gaseous 3He at the start of the experiment was 59.5% and the observed
relaxation time at BL15 was 96.6 hours. The magnetic environment device for polarized 3He cell included theadiabatic fast passage (AFP) NMR, which was a technique to measure the polarization of the 3He nuclei andreverse the direction of the 3He nuclear spin with respect to a static magnetic field. So we could detect a spin

1. Experimental method and results (continued)
Figure 2 shows the two dimensional SANS patterns on theI(+,+)
IobsSFon

small angle detector bank measured with neutrons of =3.0+)
II(-,obsSFoffÅ . It took two hours to collect each pattern. Thepolarization of the 3He nuclei was decreased to 54 % at theend of the experiments. During these measurements, we did
not change the polarity of the 3He nuclear spin. Three
Debye-Scherrer rings from silver behenate were observed in
the non-spin-flip (+, +) scattering pattern and relatively
higher background was observed in the spin-flip (-, +)scattering pattern. It was confirmed that all the small angle
detector banks were covered by the polarized 3He gas

Fig.2 2D SANS intensities measured withthe spin flipper on and off.
0.15

Intensity (Arb.Units)

analyzer.
Figure 3 shows the one dimensional SANS profile.
Because of the imperfect polarizing performance of thesupermirror polarizer and the polarized 3He spin analyzer,
these observed intensities include four components written
as follows:
IobsSFon = N+ I(++) T++ + N+ I(-+) T-+ + N- I(-+) T++ + N- I(++) T-+,
IobsSFoff = N- I(++) T-+ + N- I(-+) T++ + N+ I(++) T++ + N+ I(-+) T-+,2014.05.22 J-PARC BL15PolSANS, PHe=54%
Silver Behenate

0.10

IobsSFon
I(+,+)
IobsSFoff
I(-,+)

0.05

0.00
00.05

0.1

0.15

0.2

0.25

0.3

0.35

q (Å-1)

Fig.3 1D SANS intensities with the spin
flipper on and off.

where IobsSFon and IobsSFoff are the observed intensities with the spin flipper on and off, I(+, +) and I(-, +) are theintensity of the spin non-flip and spin flip components, N+ and N- are injected neutron with up and down spin,T++ and T-+ are transmission of the polarized 3He analyzer of the neutron with spin being parallel and antiparallel

where Icoh and Iinc are the coherent and incoherent scattering
components of the silver behenate, respectively. Figure 4
shows the I(+, +) and I(-, +) components calculated accordingwith these equation. We succeeded in separating thecoherent and incoherent scattering components by using the3polarized He gas as a spin analyzer.

Intensity (Arb.Units)

to the 3He nuclear spin. The I(+, +) and the I(-, +) can be written by

2014.05.22 J-PARC BL15PolSANS, PHe=54%
Silver Behenate

0.5
0.4

Icoh
Iinc

0.3
0.2
0.1
0.0
00.05

0.1

0.15

0.2

0.25

0.3

0.35

q (Å-1)

In conclusion, we performed polarized small-angle neutron Fig.4 Choherent and incoherent scattering
components of silver behenate.
scattering demonstration experiments on silver behenate
with using the polarized 3He gas as a spin analyzer andsucceeded in separating the coherent and incoherent scattering components. It was confirmed that the relaxation
time of the polarized 3He gas at BL15 was long enough. Because the beam time of the BL15 is very tight andmost of the experiments performed within a few days, the offline SEOP based polarized 3He analyzer is effective
and realistic option for BL15.

Please use A4-size paper for further reporting, if necessary.