Inventor of x-ray machine

In 1895, the discovery of X-rays by German physicist Wilhelm Konrad Roentgen led to the emergence of new diagnostic tools used by doctors. A few months after he discovered X-rays, Russell Reynolds built this X-ray machine. This is one of the oldest X-ray machines in the world, which enables human beings to look inside the human body without incision.

medical application scope of X-ray machine

X-ray interventional diagnosis, chest fluoroscopy, radiography, barium meal fluoroscopy of gastrointestinal tract, double contrast radiography of gas and barium, examination of gastrointestinal tract diseases, examination of large intestine diseases, examination of urinary system diseases, T-tube cholangiography, and examination of hepatobiliary system.

X-ray generator principle X-ray generator composition

I. X-ray source

II. X-ray control system

III. Power supply

I. X-ray source is composed of high-voltage multiplier, which provides filament power supply and high voltage for X-ray tube

X-ray tube is a high vacuum diode, and the cup-shaped cathode is built in. The anode is composed of an inclined tungsten target and an auxiliary heat sink.

The cooling method is sealed oil cooling circulation cooling

2. The X-ray control circuit turns on the signal to realize the voltage and filament signal required for the X-ray source, and monitors the working state of the X-ray source.

3. The power supply of the X-ray source generator comes from the power grid of 22V, and the fluctuation of the X-ray generator on the power grid is less than +/-1% (except for the requirement of voltage stabilization). The wavelength range is .6～5nm. The wavelength range of X-ray commonly used in X-ray security inspection is .8～.31nm (equivalent to 4 ~ 15 kV). In the electromagnetic radiation spectrum, it is between gamma rays and ultraviolet rays, which is much shorter than the wavelength of visible light and invisible to the naked eye.

X-ray imaging mainly uses the penetrability of rays, fluorescence effect and photographic effect

X-ray interacts with objects

1. Photoelectric effect

2. Compton scattering (incoherent scattering)

3. Rayleigh scattering (coherent scattering)

4. Electron couple effect

X-ray generation procedure is to first turn on the power supply and pass through a step-down transformer. When the step-up transformer provides high-voltage electricity to the two poles of the X-ray tube, the potential difference between the cathode and the anode increases sharply, and the free electrons in the active state are strongly attracted, so that the bundled electrons travel from the cathode to the anode at high speed and hit the anode tungsten target atomic structure. At this time, energy conversion took place, in which less than 1% of the energy formed X-rays, and the remaining 99% was converted into heat energy. The former is mainly emitted by the window of the X-ray tube, and the latter is emitted by the cooling facilities.

(Take the 14KV American Spearman radiation source adopted by Kejin Company as an example) Generator principle

X-rays are generated by the filament tube. When the filament of the tube is powered on and the voltage of +/-7V is applied to the two poles of the tube, X-rays will be emitted.

XRAY provides corresponding feedback signals for pulse width modulation for closed-loop control. The working frequency is about 3KHZ. The voltage and current are closed-loop adjusted, and it is equipped with over-voltage and over-current protection.

Working principle

The X-ray safety inspection equipment is completed by conveying the checked baggage into the crawler channel with the help of conveyor belt. After the luggage enters the channel, it will block the light barrier signal, and the detection signal will be sent to the control unit, triggering the X-ray source to emit X-ray beams. A very narrow fan-shaped X-ray beam passing through the collimator penetrates the luggage items on the conveyor belt and falls on the dual-energy detector. The high-efficiency semiconductor detector converts the received X-rays into electrical signals, and these weak current signals are directly quantized and transmitted to the industrial control computer for further processing through the universal serial bus, and high-quality images are obtained after complex operation and imaging processing.

Application

X-ray machines are widely used in the safety inspection of railway stations and airports.