DANB Radiation Health and Safety (RHS) Practice Exam

Xrays originate when electrons are propelled at high speeds toward which component of the tube?

1. Cathode

2. Electrode

3. Focusing cup

4. Tungsten target

The correct answer is: Tungsten target

X-rays are generated when high-speed electrons collide with a specific component of the x-ray tube known as the tungsten target. This target is made of tungsten because of its high atomic number, which is crucial for efficient x-ray production. When the electrons, which are emitted from the cathode, are accelerated across the tube and hit the tungsten target, their kinetic energy is transformed into x-ray photons. The interaction of the high-energy electrons with the tungsten atoms results in the emission of x-rays through two primary processes: characteristic radiation and Bremsstrahlung radiation. Characteristic radiation occurs when an electron dislodges an inner-shell electron from a tungsten atom, and the resultant vacancy is filled by an outer-shell electron, releasing energy in the form of an x-ray. Bremsstrahlung occurs when the electrons are deflected by the attractive force of the tungsten nucleus, resulting in energy loss manifested as x-rays. The other components do play roles in the functioning of the x-ray tube, but they do not directly participate in the production of x-rays. For example, the cathode is responsible for emitting the electrons, the focusing cup helps direct the electrons towards the target, and the electrode serves as a terminal for electric current, but it is the