In 1895, the discovery of X-rays by German physicist Wilm Conrad R?ntgen led to the emergence of a new diagnostic tool used by doctors. A few months after his discovery of X-rays, Russell Reynolds made this X-ray machine. It's one of the world's oldest X-ray machines, and it allowed humans to view the inside of the human body without making an incision.
Scope of medical application of X-ray machine
X-ray interventional diagnosis, chest fluoroscopy, film, gastrointestinal barium meal fluoroscopy, gas barium double contrast, examination of gastrointestinal diseases, examination of colorectal diseases, examination of urological diseases, biliary "T" tube contrast, examination of liver and gallbladder conditions.
X-ray generator principle X-ray generator composition
I. X-ray source
II. X-ray control system
III. Power supply
I. X-ray source consists of high voltage multiplier, X-ray tube
High voltage multiplier provides the X-ray tube filament power supply and high voltage
The X-ray tube is a high-vacuum diode with a cup-shaped cathode containing the filament; the anode consists of a beveled tungsten target and an accessory heat sink.
Cooling method using sealed oil-cooled circulating cooling
II. X-ray control circuit to open the signal to achieve the required voltage and filament signals provided to the ray source, and monitor the X-ray source work status.
Three. Ray source generator power supply from the grid 220V to provide, X-ray generator using the grid requirements are less than +/-10% fluctuations (except for voltage regulation requirements)
X-ray is a very short wavelength electromagnetic waves. Wavelength range of 0.0006 ~ 50nm. X-ray security commonly used in the X-ray wavelength range of 0.008 ~ 0.031nm (equivalent to 40 ~ 150kV). In the electromagnetic radiation spectrum, living between γ rays and ultraviolet light, much shorter than the wavelength of visible light, invisible to the naked eye.
Ray imaging mainly use the ray penetration, fluorescence effect and photographic effect
X-ray and object interaction
1. photoelectric effect
2. Compton scattering (incoherent scattering)
3. Rayleigh scattering (coherent scattering)
4. electron dipole effect
The procedure of X-ray generation is First the power supply is turned on and passes through a step-down transformer for heating of the X-ray tube filament, which produces free electrons and clouds them near the cathode. When the step-up transformer to the X-ray tube poles to provide high-voltage electricity, cathode and anode potential difference between the steep increase in the active state of the free electrons, by the strong attraction, so that the bunch of electrons, at high speed from the cathode to the anode line, impact on the atomic structure of the tungsten anode target. At this time the energy conversion occurs, of which about 1% of the energy below the formation of X-rays, the remaining 99% or more is converted to heat. The former is mainly emitted by the window of the X-ray tube, the latter by the heat dissipation facilities
(140KV American Spellman ray source used by the company as an example) generator principle
X-rays are generated by the filament tube, when the filament of the tube on the electricity, the two poles of the tube were added +/-70V voltage, there will be X-rays emitted.
XRAY provides the corresponding feedback signal for closed-loop control with pulse width modulation technology, the operating frequency of about 30KHZ. Voltage and current are adjusted in a closed loop and protected against over-voltage and over-current.
Working Principle
X-ray safety inspection equipment is the use of conveyor belts will be checked baggage into the tracked channel to complete. When the baggage enters the channel, it will block the light barrier signal, and the detection signal is sent to the control unit, which triggers the ray source to emit the X-ray beam. A very narrow fan-shaped X-ray beam after the collimator through the luggage on the conveyor belt fell on the dual-energy detector, high-efficiency semiconductor detector to the received X-rays into electrical signals, these very weak current signals are directly quantized, through the general-purpose serial bus transmission to the industrial control computer for further processing, after complex arithmetic and imaging processing to obtain high-quality images.
Applications
The X-ray machine is widely used for security checks at train stations and airports.