X-rays and Medical Physics

What are x-rays generally used for medically?

• Imaging bone

• Imaging soft tissue

• Imaging organs

This is an x-ray tube that produces x-rays.

Why is it surrounded by a lead casing?

• To prevent electrons from escaping

• To keep it as a vacuum

• To prevent x-rays leaving the tube and harming the user

• To prevent it over heating

This is an x-ray tube that produces x-rays.

We don't want the electrons losing kinetic energy and slowing down - what do we do so this doesn't happen?

• Heat it all up

• Keep it as a vacuum

• Increase the current

• Slow down the electrons

This is an x-ray tube that produces x-rays.

What happens at the anode?

• Electrons hit the tungsten target

• The target is rotated to cool it down

• Electrons are emitted via thermionic emission

• Protons are emitted

This is an x-ray tube that produces x-rays.

What happens at the cathode?

• Electrons hit the tungsten target and release photons

• Protons hit the target and release photons

• Electrons are emitted via thermionic emission

• Protons are emitted

This is an x-ray tube that produces x-rays.

Why is the target continually rotated?

• To heat it up

• To emit more electrons

• To release more photons

• To prevent it from overheating

This is an x-ray tube that produces x-rays.

What element is the target at the cathode usually made from?

• Tungsten

• Uranium

• Thalium

• Thorium

This is an x-ray tube that produces x-rays.

Why do the electrons accelerate across the tube?

• They are repelled by the cathode

• They are attracted to the anode

• They are free to move

• There is a pd across the tube

This is an x-ray tube that produces x-rays.

Why do the electrons accelerate across the tube?

• They are repelled by the cathode

• They are attracted to the anode

• They are free to move

• There is a pd across the tube

This is an x-ray tube that produces x-rays.

Which of these is true?

• The thermal energy of the electron is converted into photon energy

• The kinetic energy of the electron is wasted

• The kinetic energy of the electron is converted into photon energy