1904.pdf

(1)

2

for constructive interference: 2k s r ⋅ = r k r

k

_i

k

_f

d

2 sin n λ = d θ

elastic scattering: k

_i

= k

_f

(2)

Scattering pattern of nanocrystal

(3)

(4)

(5)

X-ray Scattering:

-Conventional

-Synchrotron Radiation Source

(6)

X-ray Scattering:

-Conventional Source

-Synchrotron Radiation Source

(7)

Source for conventional x-ray instrument

a sealed x-ray tube

(8)

x-rays of Mo spectrum

(9)

(10)

(11)

(12)

(13)

(14)

X-ray Scattering:

-Conventional

-Synchrotron Radiation Source

(15)

Synchrotron Radiation Facility

(16)

Storage ring at PLS

Pohang Light Source

(17)

vacuum: 10^-10~10^-11 torr

radio freq. cavity: restoring the E of e- injection system

bending magnet

focusing magnet

(18)

(19)

LINAC Storage ring

just before front-end

(20)

Monochomatization for x-ray scattering Bragg law:

n λ = 2 sin d θ

(21)

x-ray scattering

reflectivity or GIS

(22)

Reflectivity or Glancing Angle Scattering

k_x k_y

k_z

(23)

Neutron Scattering:

-Continuous source (Reactor)

-Pulsed Spallation Source

(24)

Neutron Scattering:

-Continuous Source (Reactor)

-Pulsed Spallation Source

(25)

(26)

Neutron Reactor: NIST (USA)

(27)

Guide hall

(28)

(29)

(30)

Monochomatization for Neutron Scattering (1)

(31)

Monochomatization for Neutron Scattering (2)

(32)

Velocity selector

(33)

Sample stage

(34)

Sample stage

(35)

Detector chamber

(36)

Detector chamber (1)

(37)

(38)

(39)

Beam Stop

(40)

Detector

(41)

Neutron Scattering:

- Continuous source (Reactor)

- Pulsed Spallation Source

(42)

What is the difference between x-ray and neutron?

Question:

(43)

(44)

(45)

Pulsed Spallation Source

-electron linear accelerator source:

e- > gamma-ray > photoneutron (~100 MeV, low efficiency)

-proton spallation source:

proton > neutron

(~800 MeV, high efficiency)

cooling is a serious problem

(46)

(47)

Spallation Source: IPNS (Argonne National Lab, USA)

(48)

(49)

(50)

(51)

(52)

Tips for “Data” Acquisition

(53)

Optimal sample thickness (1)

(54)

Optimal sample thickness (2)

(55)

Examples of sample thickness

(56)

Wavelength dependence of transmission

(57)

Calculation of Scattering Length Density

(58)

Coherent and incoherent scattering

(59)

Sample Scattering

(60)

(61)

Data correction and absolute scaling

(62)

Multiple Scattering

(63)

beam center diffracted spot L₂

1/L₁

this axis is normal to L1, and the length is inverse of L1

1/L₂

L₁

real lattice

unit cell from a certain angle