ProceωingsProceeding s ofof Ibe the Fi Fift自h Inlemalional International SympSymposiu叩 umm on onon Advanced Advanced NuNucleacJ .ar r Energy Energy RResearc田曲目h
-NEUTRONS—NEUTRON S ASA S MICROSCOPIC PROBES- PROBES— P-602P-60 2 NEUTRONNEUTRO N SPINSPI N ECHOECH O SPECTROMETERSPECTROMETE R ATAT JRR-3MJRR-3 M
Takayoshi Takayoshi Takayoshi TAKEDA ,， Shigehiro Shigehir o KOMURA ，, Hideki Hidek i SETO ，, Michihiro Michihir o NAGAI,， Hideki Hideki Hideki KOBAKOBAYASHI Y ASHI ,， Eiji Eij i YOKOI ，, *Tooru *Toor u EBISAEBISAW WA A andand 本*SeijSeiji i TASAKT ASAKI I
Faculty Faculty Faculty of o f Integrated Integrated Arts Arts andand Sciences ，, Hiroshima Hiroshim a University University 1-7-1 1-7-1 1-7-1 Kagarniyama Kagamiyama,， Higashi-hiroshima-shi ,， 72472 4 Japan Japan *Research *Research Research Reactor Reactor Institute ，, KyotoKyot o University University Noda ，, Kumatori-cho Kumalori-cho ,， Sen-n Sen-nan-gun 加 -gun ,， Osaka-fu ,， 590590-0 ・04 4 JapaJapan n
ABSTRACTABSTRAC T
WeW e havehave designed designed andand havehave been bee cons n constructin凶 cting g at at C 2.・22 cold cold neutron neutron guide guide port port oof f JRRJRR-3M・3M ，, JAERI ，, a neutron neutron spin spin echoecho spectrometer(NSE) spectrometer(NSE) whichwhich is is equipped equipped witwith h twotw o optimized optimized magnetsmagnet s for for neutron neutron spin spin precession ,， a position position sensitive sensitive detector(PSD) ,， a converging convergin g polarizer polarizer andand .a a widewide arl are伺叩a analyzeralyzer. . 百Thle e dynamicdynamic range range of of o f scattering scatterin g 'vector vector Q eovers covers fromfrom O.OlAO.OlA-・1' to to 0.3A.l 0.3A-" andan d that that ofof energy energy E fromfrom 30neV30ne V to to O.lmeV.0. 1 meV. This This spectrometer spectrometer makesmake s it i t possible possible to to study study aa mesoscopic mesoscopic spatial spatial spatial sstructurlrU cture e ofof the die order order of of トl~100nl00nm m combinedcombine d with with a nanosecond nanosecond temporal temporal structure structure structure of of the the order order of of 0.1-100ns 0.1 ~100ns COcorrespondinl1・ esponding g to to dynamical dynamical behavior behavior of of large large molecules molecules molecules suchsuch as as polymer. polymer. A test test experiment experiment showsshow s that that the the homogeneity homogeneity condition condition condition ofof the th e precession precession magnetmagne t is is loosened loosened byby meansmean s of of PSDPSD. .
INTRODUCTIONINTRODUCTIO N TheTh e neutron neutron spin spin echoecho (NSE)(NSE ) methodmetho d proposed proposed byb y MezeiMeze i provides provides anan extremely extremely highigh h energy energy energ y resolution resolution in in analyzing analyzing small small energy energy changes changes ono n scattering scattering as as a phase phase shift shift in in the the LarmorLarmo r precession precession of of each each neutron neutron spin spin in in a magnetic magnetic field. "l) TheTh e wavewav e veclor vector Q and and Fourier Fourier time time time t dependent dependen t correlation correlation function function I(QI(Q,t) ，t) of of an aninvestigated investigated system system is is observed observe d directly directly in in the the the NSENS E experimenexperiment t. . ThenThe n S(QS(Q,o))， ω~ can can be b ecalculated calculated from from /(Q I(Q,t) ，t) by bymeans means of o fFourier Fourier transformation. transformation. 百Thle e Fourier Fourier time time t is is given given 払as,
't=( = (2|7nN»i„司%担Nm~/h3)2//j3);iλ 3£3D> or or or in in unit unit of of s,，
F--tA、，， t[s] t[s] r[s] = 1. 1.8638635 5 xx 10 10・10λ10X,，3[A]D[Tm] 3[A]D[Tm] ，, (1、) whereλiswher e X is the the neutron neutron wavelength wavelength in in unit unit of of A andand D the the magnetic magneti c fieLd fiel d integral integral in in unit unit o of f Tm.Tm . Th e magnetic magneti c field fiel d integral integral D along along the the neutron neutron path path is is given given by.， PEE--1'aaaa， 今 崎，‘ D 岡戸」，，ιB勺& B4内 B4AV- AU = U + + m D = I |B|d/ =一- I [B?ア匂 + E}r + B]\ dl , (2) (2) J，
-959- 円 where wherewhere B: Bt,， B n andand B;B+ are are the th e axial axial z z,， radial radia l rr and and azimuthal azimutha l It
varied varied varied byb y the the magnetic magnetic field fiel d strength. strength. TheTh e maximummaximu m Fourier Fourier time time tm tm or or maximummaximu m field field
integral integraintegral l DDm m determines determines the the achievablachievable e spectraspectral l resolution resolution AE=TiAcod. E=h d. ωof o fthe th espectroscopy. spectroscopy.The The spectral spectral spectra l resolution resolution d. AEE is is defined defined by ,，
d.E d.E AE=hAo)= n d. ω= = O.050.05h/tñ/tm. • (3) (3) OnO n the the other other hand ,， the th e energy energ y resolution resolution oE6£,， whichwhic h is is determined determined byb y the the inhomogeneity inhomogeneity ofof DD,， in i n contrast contrast to to d.E AE is is given given by ，,
5E=28E = 2守A&E,E ， (4) (4) wherewher e d.DAD is is inhomogeneity inhomogeneity of of D andan d E is is the the energy energy ofof the th e incidint incidin t neutrons. neutrons. WeW e havehave designed designed an an NSENS E spectromc spectromete町r in in order order to to study study a mesoscopic mesoscopi c spatial spatia l structure structure of ofof the the order order ofof トl~100nl∞nmm combinedcombine d with with a nanosecond nanosecond temporal tempora l structure structure ofof the the order order ofof O.l-lOOns O.l-lOOns 0.1~ 100ns corresponding corresponding to to dynamical dynamical behavior behavior ofof large large assemblies assemblies mademad e ofof medium-sized medium-sized molecules molecules molecules andan d ass.:mblies assemblies ofof large large mo1ecules molecules andan d a1so also to to dynamica1 dynamica l critical critical behavior behavior ofof 2 2) 紅白 2 ・ condensed condensed condensed maUers. matters. ' TheTh e NSENS E spectrometer spectrometer sh shares the the C 22・.2 cold cold guide guide port port ofof JRRJRR-3M3M ,， lhe the monochromatemonochromater丸山, the neutron neutron guide ,， the th e sample sample table table andand 恥the dancing dancing floor floor commonlycommonl y with with the the the neutron neutro n spectral spectral modu1ation modulatio n spectrometer(NSM).3) spectrometer(NSM).3> TheTh e par part lS s whichwhich are are shared shared with with the the NSMNS M spectrome spectromete句r andand the the tables tables for for the the polarizer ,， precession precessio n coil ,， ana1yzer analyze r andan d detecto l" r have have beenbeen constructed. constructed. OtherOther parts parts are are being being constructed. constructed. TheTh e precession precession coil coil will bebe constructed constructed constructed byb y the the enden d of of MarchMarc h 19931993. . WeW e havehav e c-arried carried out out a test test experiment experiment of of NSENS E using using the the parLS part s constructed constructed andand the the parts parts ofof anoanothe出er r NSENS E spectrometer spectrometer whichwhich wew e hadha d constructed constructed at at KUKUR. R. 4) 4' In In In this this papaper.，e r,， wew e give give tthb.; ; design design of of the the NSENS E spectrometer spectrometer andand 出thaat t ofof the the precession precession coil coil in in in detei deteil l. . Finally ,， wew e demonstrate demonstrate in in 出the test test experimint experiminl of of NSENS E that that the the homogeneityhomogeneity condition condition condition ofof the the precession precession magnetmagne t is is loosened loosened byb y meansmean s ofof the the position position sensitive sensitive detector(PSD). detector(PSD). detector(PSD).
0 1-2
IE IE 12m
11m > Fi Figg.l . 1 百Thle e whole whole view view of of the the neu neutro位on n spin spin echo ech o spectrometer spectromete r at at JRRJRR-3M・3M.C2 . C2-2・2: : C2C2-・22co1d cold neutrong neutron guid凶de e port ，, M :: monochromamonochromater閣r,， G:G : nneutro側紅ong n guide凶de ，, P: P: polarizer polarizer，, PF: PF : pre precessio偲 ssion n ∞coilil ，, S: : sample sample，, AA :阻: analyzeal 戸er r and andD D: :detector detector DESIGNDESIG N OFOF THETH E SPECTROMETERSPECTROMETE R
-960--960 — WeW e havehav e designedesigned d aan n NSENS E spectrometer spectrometer at at 山theCe C2.-2 colcold d neutroneutron n guid巴e porportof t of JRR-3JRR ・3MasM as shownshow n in in Fig. Fig . 1. 1. TheTh e dynamicdynami c range range ofo f scattering scattering veevectoi" or r Q covers covers fromfro m O.OlA-1 0.01 A-1 to to 0.3 0.3AA- 1 and and that that that ofof energyenergy E fromfro m 30neV30ne V to to O.lmeV.O.lmeV . SomeSom e of of the the design design parameters parameters ofof the the spectrometer spectrometer are are are Ii liste sted d in in Table Table 1. 1. TheTh e reflected reflected neutrons neutrons byb y a multi-layer multi-layer monochromatermonochromate r al at the the C 2--22 port port pass pass through a 9m neutron guide and reach a polarizer. The monochromater has a pass through a 9m neutron guide and reach a polarizer. Theo monochromater has a wavelength wavelengthwavelength resolution resolution ofof about about 10%10 % in in the the wavelengthwavelength range range 55~8A向 8λ. . TheTh e distance distance betweenbetwee n the the the monochromatermonochromate r andan d polarizer polarizer is is aboutabout 12m.12m. TheTh e polarizer ,， the th e precession precession coil ,， the th e analyzer analyzer analyzer andan d the the detector detector table table movemov e freely freely ono n the the dancingdancing floor floor andan d the the reflecting reflecting andan d scattering scattering scattering angles angles at at the the monochromater ,， the th e polarizer ,， the th e ssampl創nple e and and the the analyzer analyzer are are set set byb y a computercompute r contro controll.百 . Theslese e tables tables havehav e beenbee n constructed. constructed. TheTh e distance distance between between the the polarizer polarizer andan d the the samplesampl e table table is is aboutabout 33.5m.5 m , ， that tha t betweenbetween the the ssampl創 nple e table table andan d the the analyzer analyzer 3.5-3.9rn 3.5~3.9rn，, andan d that that betweenbetwee n the the analyzer analyzer andan d the the detector detector 3-33~3.5m.5 m. . Fig. Fig. 2 showsshow s the the set set upu p ofof the the NSENS E spectrometer spectrometer spectrometer in in detai detail l. . It I t consists consists ofof the the following following parts: parts: A:A : polarizer ,， B:B : magnetic magnetic guide ，, C:C :
Table Table 1 DesigDesign n parameters parameters oof f the the neutron neutron spispin n echecho o spec spectromete甘ometer r dynamicdynami c range range Q 0.01 0.01 A- l1- ~ 0.3 0.3 A-»l E 3030neV~100ne neV -1 ∞μeVV
path path path length length in in precession precession field field L 2.6m2. 6 m maximummaximu m field field integral integral 0.22 0.22 TmTm relative relative relative inhomogeneityinhomogeneity ofo f field field integral integral ηTf=MJ = AD/D/D< <2 2x x 10 10-・6 6
N λ=5AA = 5 A λ=8AA = 8 A maximummaximu m spin spin turn turn numbernumbe r N刷必相 jhw' 8109810 9 129751297 5 maximummaximu m Fourier Fourier time time f(ns) 5.0 21 Jnm 5.0 21 spectral spectral spectra l resolution resolution AE(neV) 66..4 4 1. 6 川、 energy energyenergy resolution resolution 5£(neV川) 13.13.1 1 5.5.1 1
wavelength wavelengthwavelength λA 55~8町 8AA wavelength wavelengthwavelength resolution resolution AAAA/ノAλ 10%10 %
beambea m cross cross section section at at mOi1ochromater mOi1ochromater monochromater 20 Ww x50x 50bh mmmm polarizer polarizer polarizer 20 Ww x 550>()h » mmmm samplesampl e 22040' ,mmmm 44t出h πJC/12 2 coil coil 120 中* mmmm analyzer analyzer analyzer 60 ww Xx 150 bh mmmm detector detector detector 120 Ww x3 3(Xfi∞b mmmm distance distance distance betweenbetwee n monochromater-polarizer monochromater-polarizer ー~1212m m polarizer-sample polarizer-sample polarizer-sample -3.5m~3.5 m 組sample-analyzemple- 叩叫yzer r 33..4- 4 - 3.9m3.9 m analyzer-detector analyzer-detector analyzer-detector 3.0-3.0-3.53.5m m
-961--961 - A-Z O-i U-Z-l Q.J •!•'
斗り住 N ・2 rr 一一一一I! ~
11 -3.5m -3.5m 帯 3.4-3.9m ム 3.5m
cc cc Q) N Fig.2 Fig. 2 百Thle e set-up set-up of of the th e neutron neutron spin spin echo echo 叩spectrometeectrometer r at at JRRJRR-3・3MM
AA:po : polarize加担er r FF: : 1s1st t precessioprecession n coico i1 l table table KK:4 : 4t出h rc/2π/2 coil coil A-l A-A-l l : popolarize 加 iz ぽr G: : samplsample e table table K-l:K/2coiK-l :7tI2 coil l AA-2・2: : magnet magnet G-G-l l : goniometer goniometer K-2K-2: : correctiocorrection n coicoil l AA-・33: : polariz polarize釘r table table GG-2・2: : stage stage LL: : magnetimagnelic c guidguide e (vacuu(vacuum m tubelube) ) B: : magnetic magnetic guide(vacuum guide(vacuum tube) tube) G-3 :: coilcoils s (x-y-z) (x-y-z) MM: : analyzeanalyzer r C :1: 1s st t Jt/1CI2 2 cocoi i1 l G-4G -4: : sample sample M-l :: analyzeanalyzer r C-l C-l:jt/2coiC-l :7tl 2 co i1 l H: : 2nd 2n d precession precessio n coil coi l table table MM-2・2: : magnemagnel t C-2 C-2 :: correctiocorrection n coil coil 11: : 3r3rdπ d JT/fl. 2 coil coil MM-3・ 3:: goniometegoniomeler r oD: : 11s st t precession precessio n coil coil 1-1: 7tl til 2 coil coil NN: : detectodeleclor r 0-1 D-l0-1 :: precessioprecession n coil coil 1-21-2: : correctiocorr 配 tion n coil coil NN-l ・1:: positioposition n sensitivsensitive e deleclors detectors ・ DD-22: : spiral spira l coils coils JJ: : 2nd 2nd (町民俗precessiosion n coil coil NN-2・2: : vacuuvacuum m tub削除e 0-3: 0-3:D-3: vacuuvacuum m tubes tubes J-l:: precessioJ 賞α:essi on n cocoii1 l O0: : slitsli lS s EE: : 2n21 凶7tld Jt/2 coico i1 l oor r πcolln coil 1J-2・2: : spiraspiralω l coili1 s P: : beabeam m stopperSlOppers s E-l E-l:: TC/7tl 22 co coii1 l orπcoor n coii1 l J-33・3: : vacuuva 叩 umωilm coil Q: : monitomonilor r detectodeleclor r E-2 E-2 :: correctiocorrection n coico i1 l J-4J -4: : symmetrs戸nmetry y coicoil l R: : beabeam m shuttesbuuer r 1t nil /2 andan d correction correction coil ,， D:D : precession precession coil coil with with spiral spira l correction correction coils ,， E:π/2E : JC/2 (or (or π)JI ) andan d correction correction correction coil ,， F: F : pr precessio，回目sion n coil coil table ，, G:G : samplesample table table with with correction correction coils ,， H: H : precession precession
coil coil coil table ，, 1: I: 1tI JC/22 飢an d correction correction coil ,， J: J : precession precession coil coil with wit h spiral spira l correction correction coils ，, K:K : 1tI Jt/2 coil coil and and correction correction coil ,， L: L : magnetic magnetic guide ,， M:M : analyzer ,， N: N : detector ,， 0: O : sli18 slits，, P: P : beambea m stoppers. stoppers. 百Thle e polarizer polarizer (or (or the the analyzer) analyzer) is is a Soller Solle r slit slit type type assembly assembly ofof magnetic magnetic supermirrors supermirrors whichwhic h are are are composedcompose d "， of shsheet回 18 s ofo f silicon silicon wafers wafers with with altemating alternating layers layers ofof Co-FeCo-F e alloy alloy andan d V metal metal w h 2 w 2 ono n them. them. TheTh e cross cross section section ofof the the incident incident beambea m at at the the polarizer polarizer is is 20 x50x50hmm .• TheTh e reflected reflected reflected neutrons neutrons byb y the th e polarizer polarizer converge converge at at the the analyzer analyze r position position in in order order to to improveimprov e the the Q resolution resolution without withou t sacrificing sacrificing the th e intensity. intensity. Diverging Divergin g scattered scattered neutrons neutrons from from the the sample sample are are ar e reflected reflected byb y the the analyzer analyzer with with a beambea m section cross cross section of of 60 wwx15uhmmxl50hmm2 and and detected detected byb y the the position position positio n sensitive sensitive detector detector whichwhic h speci specifie自由s different different divergent divergent neutron neutron papaths血s. . 百Thle e detector detector is is an a assemblyn of assembly of 15 15 lDlD-PSD・PSDs s ofof 1/ 2 inch inch in in diameter. diameter. EachEac h lD1D-PS-PSD D is is set set vertic verticallya1 1y. . TheTh e long long long distance distance betweenbetwee n the the analyzer analyzer andan d the the detector detector reduces reduces the the neutron neutron noise noise without without sacrificing sacrificing sacrificing available availabl e intensity intensity using using PSDs.PSDs .
PRECESSIONPRECESSIO N COILCOI L ForFo r the the magnetmagne t that tha t facilitates facilitates the the LarmorLarmo r precession precession ofo neutron f neutron spins ，, wew e have have adopted adopted the the the optimal optima l field field shapeshape coil coil (OFS(OF S coil) coil) as as proposed proposed byb y ZeZeyenyen 5S>)，, whichwhic h -has has a sinusoidal sinusoida l field field
distribution distribution distribution BlB t(z) z) a1 alon0ng g the the axial axial coordinate coordinate z (approximately (approximately par parallea1 1el l to to the the neutron neutron path) path) over overover a length length L suchsuch 白紙，that,
2 B~(z)BzW = 品ficos 0cos2(^L),( 雫) • (5) (5) For For a long long conventional conventional simple simple solenoid ,， the relative th e relativ e field-integral field-integral inhomogeneityηisinhomogeneit y rj is given given as ,，
η= 企立向.L- (6) (6) D 2DsLs' '-£• 2DSLS
wherewher e D.D s is is the the solenoid solenoid
diameter ,， L. L s the the length length ofof the the solenoid solenoid solenoid andan d r the the radial radial TableTable 2. 2. DesignDesign parameters parameters ofof 出the precession precession coi coil l. . coordinate coordinate coordinate ofo f the the neutron neutron trajectory. trajectory. trajectory. ForFo r the the OFSOF S coil ,， magnetic magnetic length length L = 2.6m2. 6 m the the the relative relative field field integral integral numbernumbe r ofo f subcoils subcoils = 202 0 bore borebor of e of 1st 1s t subcoil subcoil = 219mm219 mm inhomogenertyηisinhomogenert y 77 is given given maximummaximu field m fiel d integral integral = 0.22Tm0.2 2 Tm as ,， inhomogeneity inhomogeneity without withou t correction correction = 2 Xx 10-10. 44 6 inhomogeneity inhomogeneity inhomogeneity with with 2 spiral spira l coils coils < 2x2 x 10-10 ・6 maxlmum current η=!(, = l(f)2泣 )2. . (7) (7) maximum current =∞= 100 A 2'L maximummaximu m field field = 0.17 0.17 TT numbernumbe r of of windings windings = 1802 1802 百Thle e spin spi n flippers flippers suchsuch 酪as Till1rI 2 hollowhollow conductor conductor wire wire = 6 x 12 12 x t4.1. 5 mmmm coil coil coil andan d πcoilit coil are ar e oper.ated operated (hollow (hollow 33x x9 9 mm)mm ) at at at z=. z=±U2土:U 2 positions positions with with ono n elec electrica凶 c叫l resistance resistance = 0.7500.7 5 Ji origin origin origin zz==O 0 defined defined at at the the cooling cooling system system = water water cooling cooling center center center of of the th coi e coil l. . Since Since r\η capacity capacity of of the th e refrigerator = 88.6 88.6 MJMJ/ Ih h
-963-— 963- does does not couple with D. does not couple with D, 0. 0.2 2 ' ' i ' ' ' ' i ' ' • < I | T""l I I | I I I I 1 T I I directly,， wwe e cacan n reducreduce e ththe e i ' ' ' ' i coico i1 l diametediameter r iin n ththe e OFOFS S 0.10.16 6 coilcoi l. . DecreasinDecreasing g ththe e diameter diametediameter r oof f ththe e coicoil l reducereduces s r-(ト 0.120.1 2 not nonot t onlonly y ththe e strastray y fielfield d bubut t ∞)N the ththe e coscost t oof f ththe e precessioprecession n CO 0.00.08 8 coilcoi l. . ThThe e inhomogeneitinhomogeneityη y r/ proportional proportionaproportional l tto o r2 iin n eqeq. . (7(7) ) 0.00.04 4 is iis s correctecorrected d b by y meanmeans s oof f a Mezei's Mezei'Mezei's s FresneFresnel l spiraspiral l coilcoi l. . 0O EveEven n fofor r a divergendivergent t neutroneutron n --22 -1 .5 ー0.5 O 0.5 1.1.5 5 2 path,， ththe e inhomogeneitinhomogeneityηis y X] is z(mz (m) ) corrected correctecorrected d welwell l bby y twtwo o spiraspiral l coils coilcoils s positionepositioned d aat t 0.000.003 3 z=i0.366z= iP .366L L iin n ththe e cascase e oof f ththe e 6 OFOFS S coil 6J. '. ThThe e OFOFS S coicoil l ofof this this spectrometer spectrometer spectrometer consists consists of of 220 0 戸て∞ coaxial coaxial coaxial subcoils subcoils havinghavin g O different different different lengthlengt h andan d CD diameters diameters diameters stacked stacked together. together. The bore bore ofof ththe e firsfirst t anand d ththe e 20th 20t20th h subcoisubcoil l is is 219m219mm m anand d 503mm,， respectively ,， anand d -0.00-0.003 3 the the the length length of of the th e first first andand ththe e ・2 -1. 5 -0.5 o 0.5 1.5 2 20th 20th 20th subcoil subcoil is is 2080mm2080m m anand d 273mm ,， respectivelyrespectively. . SomSome e z(mz (m) ) of of of the the design design parameters parameters oof f Fig. Fig. 3 Th e magnetic field distribution B.( z. r) 叩 d B，(z. r) at the the the coil coil are ar e listed listed in in Table Table 22. . Fig. 3 The magnetic field distribution Bz(z, r) and B/z, r) at r= 2cm when the c町 rent Is 1∞A.百 le sinusoidal curve Bl 乙r) 官Thle e maximummaximu m field fiel d integral integral n=2cm when the current is 100A. The sinusoidal curve Bz(z,r) = BBfiosH.nz/L)rf. os 2(1C:l/ L) is shown is show by n ab ydolt a dotte剖 line. d line. DmD m oof f ththe e coicoil l iis s O.22Tm.0.22Tm . 官官The magnetic magnetic length length L is is
2.6m. 2.6m. 百Thle e fieldfield distribution distributio n Biz.r) Bt(z,r) and and BBJz,r)，( z，りat atr=2cm ;-=2c mcalculated calculated from from the theOFS OF Scoil coi lwithout without any anyan y correction correction coils coils is is shownshow n in in Fig. Fig . 3. 3. In In the the curve curve of of BB/z,r),，( z.r) ， wiggles wiggle s appeappea訂r at at the the ends ends oof f 出the subcoils subcoils andan d they they increase increase with with increasing increasing r. ThoughThoug h the the wiggles wiggles cause cause the the neulron neutron depolarization ,， the th e depolar depolarizatio包ation n is i s negligible negligible in in this this OFSOF S coil coil for for r<4cmr<4c m whichwhic h wawas s designed designed designed in in the the following followin g condition: condition:
dtan 汁Br(z ，r，tt)IBz(z ， r， tt)} ]IB(z ，r ， tt) < 1似)()T.lm- 1 ， (8) (8) 07. where where the the sp spee田 d ofof 出the spin spi n rotation rotation in in 出the LamorLamo r preression precession is is at a t least least 20020 0 times times moremor e than than 出thaat t of of the the magnetic magneti c fiela fiel d direction direction for for a moving moving neutron neutron spin. spin. TheTh e deviation deviation ofof the th e field fiel d integral integral D fromfrom the the axial axial symrnetry symmetry (血(the tt 0 dependendependenc田e of of D) caused caused caused fromfrom wide wide conductor conductor wires ，, typically typicall y 12mm12m m widewid e andand 6mm6m m high ，, waswa s a serious serious problem. problem. problem. TheTh e inhomogeneity inhomogeneity fromfrom the th e deviation deviation cannot cannot beb e corrected corrected by by the th e spiral spiral coi coil l. . TheTh e winding winding winding of of the the conductor conductor wires wires andand the th e interconnection interconnection between between the th e subcoils subcoils were were designed designed in in in such such a waywa y as as to to compensatecompensate the the deviation deviation as as far far 部as possible. possible. Fig. Fig. 4 showsshow s the the ゆ -964-— 964- /'U2 /'U2 M 1t( r ，tt) = Ir {B(z {fi(z,r,0)-fi°(z,r)}d/，r， ゆ) -B O(Z ，r) } dl , ， (9) (9) Jo。 m where wherewhere B(B(zr,z.r， tt) 0) = {Br({B}{zr, z.r， tt) 1 , (:()〈与→ 3cm3c m Q司 2 - from fromfrom -Ll -LI22 to to Ll 1/2. 2. . The Th e total total < 2 - \ J relative relative relative inhomogeneinhomogeneitii: yyηof r\ of the the the spectrometer spectrometer for for 4*c4'cm m 2cm2c m neutron neutronneutron beambea m is is to to bbe e s reduced reducedreduced belowbelo w 2x2x10 10 ・6 bby y - 1 cmcm meansmean s ofof 出th e spiral spira l coilscoils. . O > ' 1 . 1 ' • I O 909 0 18018 0 27027 0 36036 0 。 Fi Figg，. 44 百Thee o0 dependence dependence of oftlle there relativ凶 ive einhomogeneity inhomogeneity of otlle f the fleld fleld field lntegral IntegraDl Dln in血 ethOFSe OFprecesslon S precessio ∞n II coicaused l cause合dom fro mwide wide conductor conductor conductor wires，. ③ m@ ← --4m-E4 ， ↑ PSI コ Fig.5 Fig.5 Fig. 5 官Thle eset setup up of oftlle th etest tes experiment t experimen of t oNSEf NS Ein iorder n orde to r tshow o sho tlle w thadvantage e advantag of ePSD o f PSfor D 泊施for the homogeneity homogeneity homogeneity conditio condition且. ADVANTAGEADVANTAG E OFOF USINGUSIN G THETH E POSITIONPOSITIO N SENSITIVESENSITIV E DETECTORDETECTO R FORFOTHE R THE HOMOGENEITYHOMOGENEIT Y CONDITIONCONDITIO N WeW e have have carried carried out out a 脳testt~~pe experimen出nentt of of NSENS E in in order order ωshowto sho w the the advantage advantage of of using using 曲thee PSDPS D for for lhe the homogeneityhomogeneity condition.τbecondition . The set set upu p ofof the the NSENS E experiment experimen t is is shownshow n in in Fig. Fig . 5. 5. P: P: polarizer ,， rrJ n/2 2: : rc/2rrJ 2 coil coil ，, PF: PF : pr precessio町田l sion n co coili!， , Al Al-Zn-Mg-Zn-Mg: : sample. sample. A: A:analyzer. analyzer.百 Thle efield field -965- integraI integraI integral D waswa s 0.015Tm0.015T m and and Aλ 7000 =7A.=7A . WeW e observed observed the the NSENS E signal signal of ofof neutrons neutrons scattered scattere d elasticaIIy elastically 6000 from from from temary ternary AIAl aallolI oy y with with 10%10 % ZnZ n 5000 印 and 0.1 % MgM g agedaged at at 808 0 o°Cc. . The The 同 NSE signals observed at different -E4000 NSE signals observed at different ouコ positions positions positions (A( A andand B)B) ono n the the PSDPS D are are 3000 shownshow n in in Fig. Fig . 6. 6. TheTh e phase phase of of ththe e NSENS E signaI signal at at the the -point point A iis s 2000 different different different fromfrom that that at at the the point point BB ,， 1000 since since since the the field field integraI integral along along ththe e ， ;， I ，~ neutron neutron neutron path path is is differen different t. . If If wew e had had D observed observed observed the the NSENS E signaI signal using using a 2.2 2.4 2.6 2.8 3 3.2 Iarge Iarge large detector detector whicwhich h iis s nonot t SymmetrySymmetr y coil coil currenl current (A(A) ) position-sensitive ,， the th e NSENS E signaI signal 2500250 0 wouldwoul d havehave disappeared disappeared as as a result result ⑥ of of of the the sumsu m ofof the th e different different phase phase 2000 signals. signals. signals. WeW e can can observe observe each each NSENS E signaI. signaI. that has a different phase 的 signal, that has a different phase -E1500 corresponding corresponding to 出e diffe 陀 nt field コ corresponding to the different field ou integrals ,， byb y meansmean s ofof the the PSPSD D whichwhic h specifies specifies the the different different 1000100 0 divergent divergent divergent neutron neutron paths. paths. TheTh e use use of of PSDPS D Ioosens loosens the the condition condition of of ththe e 500 homogeneity homogeneityhomogeneity of of the the field field integral integral D. Therefore ,， wew e can can use use ththe e 0 scattered scattered scattered neutrons neutrons with with Iarge large 2.2 2.4 2.4 2.6 2.6 2.8 2.6 3 3.2 3.2 angular angulaangular r divergences divergences for for ththe e NSNSE E SymmetrySymmetr y coil coil current current (A(A) ) experiment experiment experiment using using the the PSD. PSD. Fig.6 Fig. 6 百Thle eNSE NS Esignals signal sobserved observe dat adifferent t different positions positions positions A and andB B on on出 thePSDe PSDぉ ashown s show in n Fig. in Fig5 . S ACKNOWLEDGEMENTSACKNOWLEDGEMENT S WeW e are are very very muchmuc h indebted indebted to to Prof. Prof. Y. Y. Ito ，, Prof. Prof . H.H. Yoshizawa ,， Prof. Prof . Y. Y. YamadaYamada an叩 d Prof. Prof. Prof . 'L Y . Fujii Fujii at at ISSP ，, University Universit y of of Tokyo ，, Japan Japa n for fo r their their supports supports to to 恥the construction construction oof f the the the NSENS E sp spectromete民 trometer r andan d 10 to Dr. Dr. C.C. M.M . E. E. ZeZeyeyen n at at ILL ，, Grenoble ,， France Franc e andand Prof. Prof. Y Y. . YamaguchYama$~chii at at IMR ，, TohokuTohok u University ,， Sendai ，, Japan Japa n for fo r valuable valuable advices advices to to the the design design ofof the the the NSENS E spectrometer. spectrometer. REFERENCESREFERENCE S l)F. l)F. l)F. Mezei(ed Mezei(ed.)ふ, Neutron Neutron Spin Spin Echo. Echo, LecLectur lure e NOles Notes in in Physics Physics 128 12 8 (Springer-Verlag (Springer-Verlag Berlin Berlin 1980) 1980) 1980) 2)S. 2)S. 2)S. Komura ,， T. T . TakedaTaked a andand H. H. Seto ，, in in 白thi is s issue. issue. 3)Y.Iω3)Y. Ito，, A. A . 1. I. Goldman ，, C. C . S. S. MMajkrzak可krzak ,， L. L. Passe Passell lI， , M.M . A.A. Kelley Kelley andand D. D. G. G. DimmlerDimmler，, !SSP ISS P Report Report Report 2063206 3 (1988) (1988) 4)S. 4)S. 4)S. Komura.Komura , T. T. Takeda ，, T. T . Miyazaki. Miyazaki, M.M . SagaSaga andand S. S. Ueno. Ueno, NucNucl l. . Instr. Instr. andand MethodsMethod s in in Phys. Phys. Phys, Research ，, A25J.. A26 7 (1988) (1988) 425. 425. 55)C )C: . ~:..M. E. E. ZeZeyenyen ，, R. R . Hartmann Hartmann and and L. L. van van de de Kl Klundert undert. , IEEEIEE ETransactions Transactionson onMa Magnetic gnetics s VoVol l. . 24 ，, n O° i2 (1 (1988) 988). . 66)C )C. . M.M . E. E. ZeZeyenyen ，, ILLIL L In Internaternal l Report Report 92ZE14T92ZE14 T (1992)(1 992). . -966--966 —