実験報告書様式（プロジェクト利用）

MLF Experimental Report

提出日 Date of report
2013/09/03

実験課題番号 Project No.

装置責任者 Name of responsible person

2012P0801

Kenichi OIKAWA

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Development and application of on-beam SEOP based 3He spin filter at BL10NOBORU / BL10

実験責任者名 Name of principal investigator

利用期間 Dates of experiments

Takayuki OKU

2012.10.20 21:00 - 2012.10.24 9:00

所属 Affiliation

2012.11.22 21:00 - 2012.11.24 21:00

J-PARC Center2013.02.14 09:00 - 2013.02.16 21:00

１．研究成果概要（試料の名称、組成、物理的・化学的性状を明記するとともに、実験方法、利用の結果得られた主なデータ、考察、結論、図表等を記述してください。
Outline of experimental results (experimental method and results should be reported including sample
information such as composition, physical and/or chemical characteristics.
For expanding measurable neutron energy region up to epithermal neutrons in polarized neutron experiments[1], we developed the portable Polarized 3He Spin Flipper (PHSF), constructed a neutron spin analysis systemwith the developed PHSFs at the BL10, carried out its feasibility test, and attempted to visualize a magnetic field
generated by a Rectangular Coil (RC). Fig. 1 shows the experimental setup at the BL10. The portable PHSF
consisted of a cylindrical glass cell filled with 3He gas which was installed in an oven, and a Solenoid Coil (SC)of 20 cm in diameter and 30 cm long for holding the 3He polarization. They were brought into the beam line after
polarizing 3He gas sufficiently by our SEOP system. In Fig. 1, pulsed neutron beams from the spallation neutron
source transmitted along the z axis through a PHSF-1 for polarizing neutrons, a sample area, a PHSF-2 foranalyzing neutron spins, and were counted by a 2D-PSND consisting of a neutron scintillator andphotomultiplier tube. In attempting to visualize the magnetic field, the RC of 50×5×18mm3 size are placed atthe sample area so as to apply the magnetic field HR of the RC along to the x axis. The cells containing 3He gasesof 17 and 11 atmcm thicknesses were installed in the PHSF-1 and the PHSF-2. The 3He spin polarizations P1and P2 of the PHSF-1 and PHSF-2 were monitored by the NMR signal V1 and V2.

PHSF-1 (17atm cm: 3He gas)

Neutron beams

PHSF-2 (11 atm cm: 3He gas)

P1Pn

2D-PSNDSample
Area

P2z axisz axis

Rectangular Coil (RC)
(50 × 5 ×18 mm3)

Figure 1

Experimental Setup with the developed PHSFs at the BL101１．研究成果概要（つづき） Outline of experimental results (continued).

10.5(A)(B)
P1 0.45
P2

Ak

P1 0.45

Ak 
01T  TT  T

P2 0

3
5
Neutron wave length (A)Figure 21 A 
1tanh 1  k 
N 2 l 2 Pn 35
Neutron wave length (A)(A) Ak as a function of neutron wave length  without the RC.

(B) P2 deduced by substituting the Ak and P10.45 for Eq. (1)The spin analyzing ability in Fig. 1 was evaluated by measuring a neutron spin asymmetry defined asAk =(T+T) / (T++T) =Pn tanh (N2l2P2), (1)where T+ (T) denote the neutron transmittance with its spin s parallel (antiparallel) to the 3He nuclear spin I1 ofthe PHSF-1,  is a neutron absorption cross section of 3He, N2 and l2 are a number density and thickness of thePHSF-2. The Pn is the neutron polarization after passing through the PHSF-1 which can be determined by the P1.
Fig. 2 (A) represents the Ak as a function of neutron wave length  without the RC. Fig. 2 (B) represents the P2
deduced by substituting the Ak in Fig. 2 (A) and P10.45 obtained from the NMR signal V1 for Eq. (1). The P2 isalmost constant as expected, but it decreases more than >5Å by the background with decreasing neutrontransmittance. While the Ak with the RC is redefined asA‘k = (T+T) / (T++T) = Pn tanh (N2l2P2) sin (nHRt), (2)where n and t is a neutron gyromagnetic ratio and a time of the s rotation around the HR direction which isnamed a Larmor precession. Fig. 3(A) and (C) represent neutron 2D images measured around the 2.7Å and3.6Å, where the beam cross section is about 10×15mm2 and the neutron transmittance is T+. Fig. 3(B) and(D) denote the projection components of T+ in Fig. 3 (A) and (C) to the y axes. The areas enclosed by brokenlines in Fig. 3 (A) and (C) denote inner parts of the RC where the HR is applied along to the x axis. Difference
between the T+ in the inner part of the RC in Fig. 3 (B) and that in Fig. 3 (D) suggests to measure the s rotation
effects based on the A‘k . Fig. 4 (A), (B) and (C) represent the T+, T and A‘k as a function of  at the inner part ofthe RC. In Fig. 4 (A) and (B), the T+ and T are divided by the neutron transmittance without the RC. From theA‘k in Fig. 4 (C), the value of 1.8 Å/turn can be obtained as the s rotation period. Its value corresponds toHR4.2mTesla in Eq. (2), and it is consistent with the HR measured by a magnetic sensor directly.
These preliminary results suggest that our apparatus has the sufficient spin analyzing ability and can visualize
the magnetic field with the  range from 0.5 to 5 Å. The measurable  range will be expanded to both sides ofthe lower and upper by keeping the P1 and P2 highly and stable.
必要に応じて、A4 サイズの用紙に続きを記入して下さい。
Please use A4-size papers for further reporting, if necessary.

2１．研究成果概要（つづき） Outline of experimental results (continued).

2D image (15×15mm2)ﾞ

Projection of Y- position

(B)

(C)

(D)

Y position

Y position(A)

X position

Figure 3(A) Neutron 2D image around the 2.7Å, (B) Projection of the T+ to the y axis in Fig. (A),(C) Neutron 2D image around the 3.6Å, (D) Projection of the T+ to the y axis in Fig. (C).

T+(A)

T 

T CoilT No  Coil
Neutron wave length  (Å)

T(B)
T 

T CoilT No  Coil
Neutron wave length  (Å)

Ak

1.8Å/turnAk T  TT  T(C)Neutron wave length  (Å)

Figure 4(A) T+ in the RC as the function of , (B) T in the RC as the function of ,(C) A‘k in the RC as a function of [1] K. Sakai, J. Phys.: Conf. Ser. 340, 012037 (2012)
必要に応じて、A4 サイズの用紙に続きを記入して下さい。
Please use A4-size papers for further reporting, if necessary.

3