Transcript X-ray - KAIST

MS213
Crystallography and Diffraction
Soon Ho Kwon
Computational Materials Science
lab.
KAIST
[email protected]
10/16/2014
X-ray
X-Rays are part of the spectrum of electromagnetic radiation occupying the region between
the ultraviolet and gamma rays.
The wavelengths of X-radiation commonly used for x-ray diffraction lie between 0.7 and 2.3 Å.
Cu Kα is 1.54Å.
X-ray
A high voltage power source is connected across cathode and anode to
accelerate the electrons.
The X-ray spectrum depends on the anode material and the accelerating
voltage.
X-ray
Continuous X-ray
Characteristic X-ray
X-ray
Filter for characteristic X-ray
< Cu X-ray spectrum >
< (a) before and (b) after passage
though a Ni-filter >
Bragg’s law
CB+BD=dsinθ + dsinθ = 2dsinθ
nλ=2dsinθ : Bragg’s Law
Interference of Waves
Basic Features of Typical XRD Experiment
Detection of Diffracted X-rays
A Modern Automated X-ray Diffractometer
θ/2θ scan (coupled mode)
 General mode
 Angle of X-ray and sample = θ
Angle of X-ray and detector = 2 θ
diffraction only planes parallel to sample surface
 Preferred orientation
<Single crystal>
<Poly crystal>
θ fixed, 2θ scan (glancing XRD)
<θ/2θ mode>
<2θ mode>
 Angle of X-ray and sample = α fixed (constant, 2~3o),
Angle of X-ray and detector = 2 θ
increase the X-ray dose rate in sample surface
protect the detector from strong peak from substrate
 No preferred orientation
2θ fixed, θ scan (rocking curve)
Cu Kα + Cu Kβ
Cu Kα
 Angle of X-ray and sample = θ
Angle of X-ray and detector = 2θ fixed
Orientation of sample
 Crystallinity is better as FWHM(full width at half maximum) is smaller.
θ/θ scan
 Fundamentally, similar method to θ/2θ mode
 Angle of X-ray and sample = θ
Angle of X-ray and detector = θ
Applicable for powder, liquid sample
D-spacings and lattice parameters
JCPDF card
XRD Pattern of NaCl Powder
Merits of XRD measurement
Nondestructive method
Qualitative analysis
Quantitative analysis
Easily getting lattice parameter
Determination of small crystallite size
Phase, crystallinity, preferred orientation
Easy to operate
Schedule
일정
실험/실습 내용
장소
구분
1주
(9월 4일)
2주
(9월 11일)
3주
(9월 18일)
4주
(9월 25일)
5주
(10월 2일)
6주
(10월 9일)
7주
(10월 16일)
8주
(10월 23일)
9주
(10월 30일)
10주
(11월 6일)
11주
(11월 13일)
12주
(11월 20일)
13주
(11월 27일)
14주
(12월 4일)
15주
(12월 11일)
16주
(12월 18일)
실습 소개 및 조 편성
응용공학동 (W1)
2427호
단체
결정구조 모형 (BCC, FCC)
응용공학동 (W1)
2427호
단체
결정구조 모형 (HCP, Diamond Cubic)
응용공학동 (W1)
2427호
단체
결정구조의 이해 및 회절
응용공학동 (W1)
2427호
단체
결정구조의 이해 및 회절
응용공학동 (W1)
2427호
단체
예비
응용공학동 (W1)
2427호
단체
중간고사
응용공학동 (W1)
2427호
TEM의 소개 및 실습
KARA
조별 (A)
TEM의 소개 및 실습
KARA
조별 (B)
X-ray diffractometer의 소개
응용공학동 (W1)
2427호
단체
X-선 회절 분석
KARA
조별 (A)
X-선 회절 분석
KARA
조별 (B)
고분해능 / Pole-figure X-선 회절 분석
응용공학동 (W1)
2427호
단체
예비
응용공학동 (W1)
2427호
단체
기말고사
응용공학동 (W1)
2427호
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