By Dr: Mohamed Afifi Lecturer Radiological Science The X-ray Production By Dr: Mohamed Afifi Lecturer Radiological Science
History of Radiology November 11, 1895, Wilhelm Conrad Roentgen Roentgen the first Nobel prize in physics in 1901
How They Were Discovered Röntgen discovered the new ray while working with a cathode tube in his laboratory.
The tube was a glass bulb that had positive and negative electrodes inside. When the air was removed from the tube, and a high voltage was applied it produced florescent glow.
To further observe the rays he positioned a screen in front of the tube. He began placing various objects between the screen and the tube that was emitting the X-rays.
He discovered that the rays or “invisible light” passed right through pieces of black paper and thin sheets of aluminum and copper but that the light did not pass through blocks of lead and his bones, and instead these objects casted shadows on the screen.
Roentgen’s Wife’s Hand X-ray of a colleagues hand after presenting the“new ray” to the Physics – Medical Association 1st X-ray? Roentgen’s Wife’s Hand
X-Ray-Tube The main parts of the x-ray tube are Cathode/filament Anode/target Glass/metal envelope Accelerating voltage
X-Ray-Tube
X-RAY PRODUCTION X-rays are produced when electrons are accelerated through a potential difference strikes a metal target. Bremsstrahlung x-rays Characteristic x-rays
BREMSSTRAHLUNG Bremsstrahlung (braking) x-rays are produced when incident electrons interact with nuclear electric fields, which slow them down (brake) and change their direction.
Bremsstrahlung Radiation
BREMSSTRAHLUNG
The majority of x-rays produced in x-ray tubes are via the bremsstrahlung process. Bremsstrahlung x-ray production increases with the accelerating voltage (kV) and the atomic number (Z) of the anode.
BREMS. EMISSION-CONTINUOUS
Characteristic radiation Characteristic radiation is produced when inner-shell electrons of the anode target are ejected by the incident electrons. To eject a bound atomic electron, the incident electron must have energy greater than the binding energy.
CHARACTERISTIC X-RAY
The resultant vacancy is filled by an outer-shell electron, and the energy difference is emitted as characteristic radiation (e.g., K-shell x-rays, L-shell x-rays), as shown in Fig.
CHARACTERISTIC EMISSION- LESS POLYENERGETIC
X-RAY EMISSION SPECTRUM BREMS INTENSITY X-RAY ENERGY
X-RAY EMISSION SPECTRUM L-CHARACTERISTIC K-CHARACTERISTIC BREMS INTENSITY X-RAY ENERGY