X ray tubes types and advancements

1. BRAINWARE
UNIVERSITY
Name- Anwesa Sardar
Student code- BWU/BRI/20/012
Semester- 3rd
Subject Name- Contrast and special radiography
procedures
Subject code- BMRIT 304
Topic name- X-ray tubes their types and advancements

2. CONTENTS
Introduction
Crookes tube and Coolidge Tube
Stationary anode X-ray tube and Rotating anode X-ray tube
Grid controlled X-ray tube and metal ceramic X-ray tube

3. INTRODUCTION
X-ray tube is a tube which is air evacuated and produce X- rays.
It mainly produce and attract electrons.
It’s basic principle is High voltage across anode and cathode, emitted electrons and interact
and produce X-rays.
Types: According to cathode: a) Cold cathode tubes(Crookes tube)
b)Hot cathode tubes (all other types)
According to anode: a) Stationary anode X-ray tube
b) Rotating anode X-ray tube
c)Grid controlled X-ray tube
d)Metal ceramic X-ray tube

4. CROOKES TUBE: Invented by William Crookes;
Used till 1920.
 Operation: High speed electron strike anode;
100 kv DC voltage between across cathode and
anode.
 Anode and cathode made up of Al.
 Disadvantages: 1.Unreliable
2. Over-heating problem
COOLIDGE TUBE: Improved by William
Coolidge;
 Characteristics: 1.High vacuum
2. Thermionic emission
 Tube envelope: 1.Made of Borosilicate(Pyrex)
2.Internal pressure 10^-8
mmHg
 Anode and cathode made up of Tungsten.
 Operation : X-ray produced by Bremsstrahlung
and characteristics method
 Advantages: Stability

5. ROTATING ANODE X-RAY TUBE: This is an
improvement of Coolidge Tube.
 Highly evacuated; Internal pressure 10^-8 mmHg
 Anode stem- Molybdenum; high melting point (2620°C)
 Rotor- copper and iron (Rotates 3000-9000 rpm)
 Focusing cup- effectiveness depend upon Shape, size etc.
 Filament – Dual; 90%tungsten & 10% thorium
 Advantage: Larger in size.
STATIONARY ANODE X-RAY TUBE: Anode and
cathode are kept in a evacuated glass envelope.
 The cathode consist of a tungsten filament; when it
hitted to white light, it emits electron.
 The anode is made up of copper block.
 Anode angle is usually 15-20 degree.

6. GRID CONTROLLED X-RAY TUBE: It has three
electrodes – Anode, cathode and focusing cup.
 The grid is electrically negative
 Since the cup and filament are close together, the
voltage necessary to cut off the tube current is not very
large.
METAL CERAMIC X-RAY TUBE: It is a high performance X
ray tube introduced by Philips Medical System.
 Tube has a metal casing and ceramic insulators.
 Aluminum oxide is a commonly used ceramic insulator.
 Three ceramic insulator are used.
Advantages: 1.Longer tube life
2.Lesser off-focus radiation.