スライド 1

AccLab BmSci ICR
KyotoUniversity
VCN-SANS EXPERIMENTS WITH
MAGNETIC LENS FOR PULSED
NEUTRONS
27. 09. 2009 Japan Physics Society conference 2009 Sep. in Kumamoto Univ.
1
Introduction
■Magnetic Lens for Pulsed Neurton beam
・The spallation neutron sources based on the accelerator
- SNS(ORNL), ISIS(RAL), J-PARC ・The magnetic lens which is applicable to pulsed white neutron
beam
>>> deveropment of
rotating-Permanent Magnet Sextupole; rot-PMSx
■VCN(Very Cold Neutorns) - compared with Thermal neutrons
・longer wavelength（~40Å）-> large scale structure,
high spacial resotuion
・lower energy (~50µeV) -> less excitation
・easier to focuse (~0.5m for 40Å)
High Resolution
2
27th Sep. 2009
JPS09. at Kumamoto Univ.
VCN-SANS
presented by Kyoto Univ. ICR. M. Yamada
VCN - Very Cold Neutrons -
3
Thermal … 25meV, 2200m/s, 1.8Å
VCN … 1~100µeV, 10~100m/s, 20~200Å
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Introduction
■Magnetic Lens for Pulsed Neurton beam
・The spallation neutron sources based on the accelerator
- SNS(ORNL), ISIS(RAL), J-PARC ・The magnetic lens which is applicable to pulsed white neutron beam
>>> deveropment of
rotating-Permanent Magnet Sextupole; rot-PMSx
■VCN(Very Cold Neutorns) - compared with Thermal neutrons
・longer wavelength （~40Å）
-> large scale structure,
high resolution
・lower energy (~50µeV) -> less excitation
・shorter focal length (~0.5m for 40Å)
High Resolution
4
27th Sep. 2009
VCN-SANS
JPS09. at Kumamoto Univ.
inILL
presented by Kyoto Univ. ICR. M. Yamada
Contents
‣about rot-PMSx
‣Focusing Test of rot-PMSx
‣VCN-SANS Demonstration Experiments
‣Conclusion and Future Prospects
5
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
rot-PMSx
- magnetic lens for neurton -
6
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
7
About rot-PMSx
・Sextupole Magnet Composed of Permanent Magnets
・modulation by rotating double ring array structure
(<->spin flipper in J-SANS-J at JAEA)
・bore ; ø15mm,
magnet length ; 66mm,
frequency of modulation ; ≤ 25Hz
・filed gradient ; 1.5x104 ≤ g’ ≤ 5.9x104T-2/m
27th Sep. 2009
JPS09. at Kumamoto Univ.
Sinusoidal modulation
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Institute Laue-Langevin (France)
reactor
53~57MW
Level D
VCN
UCN
turbine
PF2
8
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
Focusing VCN Measurements with
rot-PMSx
Season 1
ILL(Grenoble, France)
PF2-VCN -BUNYIP
Jun. ~ Aug. 2009
9
27th Sep. 2009
JPS09. at Kumamoto Univ.
Dr. N. Yamada (KEK)
presented by Kyoto Univ. ICR. M. Yamada
10
Synchronization between rot-PMSx and pulsed VCN
ToF method
7.0
6.0
G' [T/m 2] zf=2.2 @2.6m
38Å
28Å
5.0
4.0
3.0
y = 2.2*c os ((m0/30-m1)*pi)+3...
íl
ÉGÉâÅ[
m1 0.18399 0.048212
ÉJÉCÇQèÊ 0.19101
NA
R 0.98274
NA
2.0
48Å
60ms
67-113 m/s
28-48Å
1.0
0
27th Sep. 2009
10
1Å step
20
30
Time [ms]
JPS09. at Kumamoto Univ.
40
50
60
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Focusing tests
setup overview
11
season 1
(
a+b=325mm
c=d=2275mm
2Zf = 2275mm
■tof length : 4875mm
■optics : ø3mm - ø14mm
■frequency : 16.7Hz(60ms) ■opening angle : 1ms
■polarized by magnetic super mirror (by K. Andersen)
■spin transport field : > 50Gauss
■band width : 30 <λ< 48Å
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Beam Profile of PF2-VCN@ detector position
12
30~48Å(200~50m
35Å
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Focusing Test results 1
27th Sep. 2009
JPS09. at Kumamoto Univ.
2D Gauss fit
presented by Kyoto Univ. ICR. M. Yamada
13
AccLab BmSci ICR
KyotoUniversity
Focusing Test results 2
14
2D Gauss fit
The optimum delay
=
14ms
by detailed
measurements.
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Focusing Test results 3
In Focus (14ms)
27th Sep. 2009
JPS09. at Kumamoto Univ.
15
Beam size
Out of Focus (0ms)
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Comparison with v.s without lens
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
16
AccLab BmSci ICR
KyotoUniversity
VCN-SANS with rot-PMSx
Season 2
ILL(Grenoble, France)
PF2-VCN -BUNYIPAug. ~ Sep. 2009
Dr. S. J. Kennedy
(ANSTO)
M. Yamada(Kyoto Univ.) and
17
VCN cabin 27th Sep. 2009
Dr. P. Geltenbolt(ILL)
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
VCN-SANS
setup overview
(
a+b=250mm
c=2265mm
18
season 2
(
d=2265/2565mm
e=100/452mm
■tof length : 4780/5030mm
■optics : ø5mm - ø14mm
■frequency : 16.7Hz(60ms)
■opening angle : 3ms
■polarized by magnetic super mirror (by K. Andersen)
■spin transport field : > 50Gauss
■band width : 30 <λ< 48Å
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
VCN-SANS
19
samples
・Pluronic (PEO-PPO-PEO) F-127 in D2O
; temperature = 4, 29, 51, 70℃
・Haemoglobin (biological sample)
・Zinc Ferrite ZnFe2O4 (nano crystal)
; particle size = 9, 15, 21, 90nm
・Polyethylene -Shish Kebab
Pluronic in Quartz Cuvette
(has emormous mechanical strength due to
plastic deformation)
ZnFe2O4
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
20
About Pluronic in D2O
T<15℃
unimer
T1~30℃
PEO
PPO
polymer solution
of triblocks
PEO
T1 < T2
T~20℃
T2
formation of spherical micelle
loss of long range ordr
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
21
VCN-SANS results of Pluronic 2
courtesy of Shane J. Kennedy (ANSTO)
100
10
T=60℃
10
T=50℃
1
T=30℃
1
T=70℃
T=51℃
T=20℃
T=29℃
T=14℃
T=13℃
0.1
0.1
0.01
0.001
1
0.01
0.01
0.1
-1
Q(Å )
Pre. Meas. at SAND(IPNS)
27th Sep. 2009
JPS09. at Kumamoto Univ.
0.001
1
0.01
0.1
Q(Å-1)
VCN-SANS
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
22
VCN-SANS v.s SAND@IPNS
T~30℃
SAND @ IPNS
100
I(Q)(arb. units)
10
VCN-SANS 465mm
VCN-SANS 100mm
1
0.1
0.01
0.001
1
0.01
0.1
Q(Å-1)
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Conclusion
■We are developing the rot-PMSx for the purpose of focusing of white
pulsed neutron beam without significant chromatic aberration.
; the bore diameter = φ15mm、magnet length = 66mm、sexutupole field
gradient 1.5x10 4 ≤ g’ ≤ 5.9x104 Tm-2
■We confirmed the beam size was kept constant for over of
wavelength range of 30~48Å with focal length of ~ 2.3 metres, using the
PF2 (VCN) beam line at ILL.
■We utilized the beam for VCN-SANS with four samples.
23
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
Future Prospect
A. Up grade of rot-PMSx
・The optimum focusing power for VCN (bore radium,
magnet length, etc）
・The stable rotation system
B.Upgrade the VCN-SANS beam line
・the detector (optimize for the VCN)
・the optical table and fine tuning
・the vacuum system all over the beam line
・decrease the back ground
・the spin guide field to keep the polarization
High Resolution
24
27th Sep. 2009
JPS09. at Kumamoto Univ.
VCN-SANS
presented by Kyoto Univ. ICR. M. Yamada
25
Appendix
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
26
Modulation by rotating double ring structure
Sinusoidal modulation
27th Sep. 2009
JPS09. at Kumamoto Univ.
angle
B[T]
g’[T/m2]
0
1.65
5.88E+04
60
0.41
1.48E+04
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
rot-PMSx
27
の製作と改良
磁石配置
永久磁石：大掛かりなシステムが必要なく、コンパクトなサイズで
大きな磁束密度をボアに発生させられる
磁石配置
：Extended-Halbach type（拡張ハルバッハ型）
内輪
外輪
直径
15/36mm
40/80mm
磁石
NEOMAX
-32AH
NEOMAX
-48H
ピース
12
+6(pole)
12
Normal
…容易化軸
…磁力線
Extended
Permendur
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
中性子ビーム集束の原理
28
- Sextupole と中性子の磁気能率
六極磁場中の中性子の運動方程式
;
中性子ビーム集束の図
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
29
VCN集束実験セットアップ 3. rot-PMSxの磁場分布
■ボア内部の磁場強度
：DTM-151（１軸ホール素子のデジタルテスラメータ、 GROUP3社製）
angle
B[T]
g’[T/m2]
0
1.65
5.88E+04
60
0.41
1.48E+04
27th Sep. 2009
JPS09. at Kumamoto Univ.
変調の振幅が計算値より約２割小さい。
・磁極補強のために用いた鉄製のネジの
分、飽和磁化が低下した。
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
30
The prototype of rot-PMSx
inner array
outer array and rubber belt
27th Sep. 2009
JPS09. at Kumamoto Univ.
運転中のrot-PMSx
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
31
The effect and application
If neutrons are focused....
‣the intensity
‣the spacial resolution
rot-PMSx in SANS
experiments
(detector focus set up)
・intensity
・extended qmin
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
32
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
rot-PMSxのパルスVCN集束実験
ver.1 磁場強度半固定
ILL PF2-VCN
Jun. 2008
33
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
偏極パルスVCN集束実験 ver.1 強度半固定概要
34
施設： ILL(Grenoble,France)
装置： PF2 (VCNビームライン)
Experiment ： No. TEST-1454
■PMSxを0º, 31.7º, 50º, 60ºに固定し、
1run10000sで偏極パルスVCNビームの
集束を観測した。
強
・ø1mmを倍率３倍
で観測
・焦点距離
Zf=0.54m
中
弱
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
VCN集束実験 ver.1 セットアップ (全体図)
35
Neutron
Thin Lens 近似
・
(
a=0.72m
b=2.14m
Zf = 0.54m
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
VCN集束実験セットアップ 1. ビームのパルス化
36
■ディスクチョッパー(直径400mm，t15mm，回転周期122ms，2スリット)
1. ToF法を用いるため、原子炉からやってくる定常ビームをパルス化する。
•ビームの繰り返し周期：61ms(66Å)
•開口時間：3.1ms/61ms ⇒ 時間分解能があまりよくない
2. スリット横につけた磁石とモーター固定枠に取り付けられたピックアップコイルで検出器にDAQ
をスタートするトリガー信号を与える。
magnet
picup coil
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
VCN集束実験セットアップ 2. VCNビームプロファイル
37
Dr. Geltenbort(ILL) 提供
60Å
20~200Å
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
38
VCN集束実験セットアップ 2. VCNビームプロファイル
Dr. Geltenbort(ILL) 提供
偏極スーパーミラー
・スピンの選択
・20~100Åの波長を
ビームラインに反射
(反射率：〜80%)
60Å
20~100Å
20~200Å
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
パルスVCN集束実験 ver.1
検出器とDAQシステム
39
■二次元Position Sensitive Detector(2D-PSD)：
中性子シンチレーションスクリーン(ZnS/LiF6)＋抵抗分割型PMT
■DAQシステム：PSD2Kモジュール (KEK 佐藤節夫氏ら開発)
●spacila resolution
：~1mm
●time resolution
：1ms
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
パルス極冷中性子集束実験結果1
・統計が足りないのである時刻の前後5msのカウント数を座標ごとに足している。
・S/Nを上げるために重心の周りの各16mmに領域を区切っている。
■０°：最も強い磁場強度
■31.7°：中間の強さの磁場強度
Counts[1/11
ms]
Counts[1/11
ms]
Y[mm]
Y[mm]
vertical
vertical
x[mm]
x[mm]
holizontal
holizontal
✓重心のy座標が移動している
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
41
パルスVCN集束実験 ver.1 結果2
各時刻のスポットサイズの定量的な評価：重心からの距離の標準偏差を比較
■０°：最も強い磁場強度
■31.7°：中間の磁場強度
最大磁場強度のとき、
~40Åの中性子に対し
て0.5mの焦点距離を
持ち、最短1mで集束
できる。
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
42
パルス極冷中性子集束実験考察
■重心の移動
中性子の重心がy方向にだけ時
間的に動いているのが観測され
た。
Disk Chopper
VCNの速度が
~100m/sと非常に遅
いために重力効果が
顕著になり観測され
たと思われる。
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
偏極パルスVCN集束実験 ver.2
43
VCNビームプロファイル
ToF at 4875mm
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
Focusing VCN Measurements with
rot-PMSx
Season 1
ILL(Grenoble, France)
PF2-VCN
Jun. ~ Aug. 2009
44
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
Beam Profile of PF2-VCN@ after chopper
45
20~80Å
(200~50m/s)
40Å
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
偏極パルスVCN集束実験 ver.2
27th Sep. 2009
JPS09. at Kumamoto Univ.
46
VCNビームプロファイル
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity
VCN集束実験セットアップ 4. 検出器とDAQシステム
47
■ 2D-PSD (二次元Position Sensitive Detector)：MSGC
(Micro Strip Gas Chamber) (byG. Manzin, B. Guerard)
・High Voltage : 1600V
・Threshold : 0.5V
・He gas : 2bar
+ CF4(stopping gas) : 2.5bar
・detector area : 80 x 80mm
・ADC：256(X)x256(Y)x64ch(t)
●spacial resolution
X：3.4mm / Y :1.5mm
●time resolution：1ms
2D
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
2D-ToF
AccLab BmSci ICR
KyotoUniversity
VCN-SANS with rot-PMSx
Season 2
ILL(Grenoble, France)
PF2-VCN -BUNYIPAug. ~ Sep. 2009
48
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
VCN-SANS sample holder -Cronulla Cryostad
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
49
AccLab BmSci ICR
KyotoUniversity
VCN-SANS
detector
50
season 2
2D-PSD bidim26 (MWPC)
by B, Guerald(ILL)
detection area : 260x260mm
resolution : ~4mm
27th Sep. 2009
JPS09. at Kumamoto Univ.
presented by Kyoto Univ. ICR. M. Yamada
AccLab BmSci ICR
KyotoUniversity

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