basis hfr ibr-2 user policy collaboration

5th workshop on scientific collaboration/JINR/Dubna 17-19.01.05 HJL

Basis HFR IBR-2 user policy collaboration

Project REMUR: Investigation of the structure of nano-objects in films of magnetic and nonmagnetic materials including new Larmor precession devices

Project Spin-Echo: Feasibility study of time-of-flight spin echospectrometer at IBR-2.

Project EPSILON/SKAT: Investigation of strain/stress and texture on geological samples

Project YuMO: Investigation of nano - and mesostructures via small-angle neutron scattering

Neutrons at IBR-2

User meeting, June 2004, at FLNP/JINRProjet leader meeting, October 2004, at Uni Goettingen


Project DN-12: Neutron studies of microsamples under high pressure

Project FSD: Internal stresses in functional materials studied by the high resolution Fourier neutron diffraction technique

Project: DAQ and CI - Development of Data Acquisition Systems and Computing Infrastructure for the IBR-2 spectrometer complex.

Project: Gas Neutron detectors


Advanced Reflectometry with Larmor Precession

Nanoscience Biology Horizontal Reflectometer Angular and Energy Encoding


stripe arrays

Nano-structures: needs for nano-characterization

imbedded nanoparticlesin polymer matrix

magnetic multilayer films

MONITORING of theINTERNAlL STRUCTURE

in VARIOUS NANOSYSTEMS

multilamellar vesicles for biochemical applications

buried quantum dots

Nanowires in mesoporous silica


Nano-structures “as seen” by neutrons

MONITORING of theINTERNAlL STRUCTURE

in VARIOUS NANOSYSTEMS

multilamellar vesiclesfor biochemical applicationsstripe arrays

imbedded nanoparticlesin polymer matrix

magnetic multilayer films

buried quantum dots

Information about the transverse and lateral structure (magnetic and non-magnetic) is encoded in the 2D scattered intensity -> comprehensive data analysis is needed

Nanowires in mesoporous silica


Sample

Precession magnetic fields (solenoids)

Polarizer(supermirror,

Heusler)

Polarization analyzer

Detector

1B

2B

,S Q

0P

2L1L

1v

2v

outP

11 1 1

1L

Lt B

v

The principle of Neutron Spin Echo

22 2 2

2L

Lt B

v

1 1 2 21 2

1 2NSE

B L B L

v v

1B

P L LB

2B


1L

The principle of Neutron Spin Echo1P

2L1

Sample

,S Q

1

1

1

v

v


Larmor precession angle

LlH/vn

L=2.916 kHz/Oe

Larmor precession for encodingLarmor precession for encoding and and

vn

Sample position outside (s1) or inside (s2) LP-device

n

polarizedneutrons

S1S2

Magnetic field H

l

Current sheetsDetector Analyzer

(s1) sensitive to and and (s2) H perpendicular to P; scattering f(M)(s3) divergent incoming beam for GISANS

Pulsed white beam


Reflected

Direct

Det. Analyzer Sample LP-device Res. spin flipper

Reflected beam

Direct beam

H

Encoding of Encoding of with with LPLP-device-device

Top view

Polymerfilm sample


*direct and reflected beams in phase*Spin-asymmetry SA = (I+-I-)/(I++I-)

H = 20Oel = 0.473m


spin up

Det. Analyzer Sample(after LP) LP-device Res. spin flipper

Reflected beam

Direct beam

H

H=18.8 Oederived from oscillations

Polymerfilm sample




Reflected beam

Direct beam

H

H=18.8 Oe H=17.5 Oe

Polymerfilm sample


SA for H=17.5 Oe SA for H=17.5 Oe and H=18.8 Oe

SA (H=17.5 Oe) - SA(H=18.8 Oe)

Encoding of Encoding of as a function of H as a function of H

Polymerfilm sample


Reflected

Direct


Reflected beam

Direct beam

H

Encoding of Encoding of with with LPLP-device--gain in intensity-device--gain in intensity

Top view

Polymerfilm sample

Incoming converging beamOverlapping but encoded signal


Reflectometry with Larmor precessionReflectometry with Larmor precession

Det. Analyzer LP-device Res. spin flipper

Reflected beam

Direct beam

HSample

Fe-Cr sample - “AF” ordered -near remanent field

Fe-Cr multilayer sample inside LP-device


Out-of-plane (and in-plane) Larmor precessionOut-of-plane (and in-plane) Larmor precession

M1

M2

Simultaneous measurement with in-plane and out-of-plane spin directionAccess to out-of plane magnetisation and full depth profile of in-plane magnetisation

Determination of the total magnetic moment and its directionDetermination of the layer-by-layer magnetization

magnetization

spin rotation axis



Angular and Energy Encoding for Nanoscience REMUR equipment including neutron guide and cold moderator Reflex equipment (cold moderator) Biology-Horizontal Reflectometer

Note:Study for investigation of 3rd co-ordinate (GISANS)



V.Lauter-Pasyuk TU MünchenW.Petry TU MünchenM.Jernenkov ILL GrenobleH.J.Lauter ILL Grenoble

A.Ioffe FZ JülichT.Brückel FZ Jülich

P.Schmiedel Uni Halle

K.Jernenkov FLNP DubnaV.Bodnarchuk FLNP DubnaA.Petrenko FLNP DubnaV.Aksenov FLNP DubnaA.Belushkin FLNP Dubna


Top view of IN3 with spin echo option ZETA

B

Heusler analyzer

sample area

3He detector

Heusler monochrom.

double RF-flippers(bootstrap coils)

mumetal shield

monitor counter

PG-filter

couplingcoils

1 m

Residual internal field ~ 5 mG.

„Precession“ length - 55 cm

Frequency range 50 – 750 KHz corresponds to effective fields 35 G – 1 KG


Three axis spectrometer IN3 with spin echo option ZETA.The magnetic shields are opened to show the two flipper coils in each arm

double RF-flippers(bootstrap coils)


, coscos( ) ,outNSEzP dQ R QQd S

What does Neutron Spin Echo measure?

( , ) is probability of a neutron being scattered with energy change and momentum transfer S Q Q

cosine FT of ( , ) with respect of .outzP S Q

L. Van Hove, Phys. Rev. 95, 249, (1954)

, ,Re Reoutz NSE

NSEi iQRP d S Q dR G Re e

3( , ) ( , ) ( , ) iQRNSE NSEI Q d R r t r R t e

, , , density-density correlation function NSE NSEG R r t r R t

0 12

outd z

II P

Re ( , )outz NSEP I Q

22

0

For example:

( , ) ; ( )outz NSE NSE NSE

NSES Q P LBe

basis hfr ibr-2 user policy collaboration

Documents

larmor precession angular

plane spin directionaccess

oesa h

larmor precession v

neutron guide

khzoelarmor precession

investigation of nano

jernenkov flnp dubnav