• Molybdenum(Mo); Alloy of tungsten and rhenium (Re)
Release Heat
• Rotational Anode • Cool system for
larger power X-ray tube
热负荷：
X-Tube 的容量
特殊X-ray Tube
X - ray
A kind of electromagnetic wave, radiate with higher energy than those of visible light. Their wavelengths are from 0.01 Angstrom to 100 Angstrom.
Structure of Cathode
• 圆焦点型 • 线焦点型 • 双焦点型 • 凹面阴极
电子聚焦阴极与二次电子(阳极过热发出)
The Choice of material of Anode
Target: Tungsten, Main body: Copper Cu
• High melting point and high thermal conductivity • Relatively High efficiency to emit X-ray
Conditions of Generating X-ray
• Electrons with high speed • Object used to block(stop) electrons stream
——Target
电子（带电粒子）与物质的相互作用：
碰撞损失
电离与激发
辐射损失
散射和轫致辐射
Equipment of Generating X ray
X射线的转化效率，同样速度和数目的电子轰击原子序数Z不同 的各种物质做成的靶，产生X射线光子的总数和光子总能量与Z2成 正比。
• Because only 0.2 percent of the kinetic energy of electrons is converted into X-rays ,while the remaining 99.8 percent is changed into heat. For conduct and release the heat, Cu is a suitable material.
• Triode X-ray Tube：高速X射线摄影 • 软X射线管： 钼靶，低管电压，主要用
于乳腺等软组织检查
Focus
Actual Focus(Actual focal spot): The area on anode that is struck by electrons is actual focus. Effective Focus: The projected area of actual focus is effective focus. Target angle: the angle of the target relative to the electrons stream.
• X-ray Tube • Low Voltage Power Supply • High Voltage Power Supply • Control circuit: variable resistor
Tube current Tube voltage
sketch map
Structure of X-ray Tube
filament, which is made from material tungsten (W).
3.Anode: it is also a target, whose surface is bombarded by these
electrons from the cathode.
About glass shell and cathode
1.Glass Shell:It compose a highly vacuum glass envethe Cathode and the anode.
Vacuum: P < 10-4 Pa
2.Cathode:Cathode is a source of electrons, actually it is also a
Discover of X-ray
In 1895, a German physicist Roentgen discovered a unknown rays which have high energy and can not be seen by eyes but can transmit some nontransparent matters. Because people in that time didn't’t understand the properties of that ray, so named it x-rays, also is Roentgen rays. Before long xray photography was developed which is a revolutionary tool in medical diagnosis. He won a 1901 Nobel Prize.
• Why X-ray tube need a condition of high vacuum oxidation, disturb electrons stream
• Filament of cathode a small coil of tungsten wire when it is heated to incandescence electrons are released from the surface of the filament. the higher the temperature of the filament, the greater the rate of electron emission.