文档介绍：绪论
Chapter 3. X-Ray Diffractometry
第三章 X射线衍射分析
Reference:
1. R. Jenkins, . Snyder.
X-Ray Powder Diffractometry.
2. 王培铭、许乾慰。材料研究方法
Prof. J. Lin
Discovery of X-Ray
X-ray was discovered in 1895 by Wilhelm Roentgen, a
German physicist.
The discovery was owing to an experiment by using a
cathode ray tube, which is a glass bulb with electrodes,
evacuated of air, displays a fluorescent glow when a high
voltage current is passed though.
When he shielded the tube with heavy black cardboard,
he found that a greenish fluorescent light could be seen
from a screen 9 feet away.
The rays can pass through most substances, including
the soft tissues of the body, but left the bones and most
metals visible. One of the earliest photo about X-ray was
a film of Roentgen’s wife, Bertha's left hand with a ring,
produced in November 8, 1895.
Roentgen submitted munication one month later.
He called it X-radiation to denote its unknown nature.
Today, X-ray is known as a kind of ic
radiation.
1
绪论
ic Radiation
ic Radiation
Cu-kα Blue Radio
X-Rays Light Waves
Wave Å 400nm 1m
length (10-10m) (10-7 m)
Frequency 1018 Hz 1015 Hz MHz
(108 Hz)
Energy 10-16 J 10-19 J 10-27 J
(103 eV) (1 eV) 10-8 eV
•X-Rays: Short wavelength, High frequency,
High energy
2
绪论
X-Ray time line
X-ray properties
X-rays are high energy ic rays
–Ionizing radiation: interact with materials
and core electrons are ejected.
-Capable of exposing negative film.
X-rays can damage human tissue
–Undetectable by human senses
–Personnel monitoring used to detect exposure
X-Ray Detector
3
绪论
X-Ray in the Nature
The radiation dose and the effects on human
4
绪论
Production of X-Rays
X-ray is produced by suddenly decelerated of high-speed electron
beam or other high-energy beams such as γ-ray, X-ray and protons.
X-Ray
X-Ray
X-Ray
X-Ray
Accelerating voltages: 5-50