1. X-ray production
Unit 20 strand 1 (P2)
Describe the production of x-rays and ultrasound

2. X-rays were first discovered in 1895 by the German
physicist William Roentgen, when using a Crookes
tube
He called them ‘x’ rays, ‘x’ for ‘unknown’.

3. The first x-ray
photograph:
Roentgen’s wife
Bertha’s hand

5. X-rays are electromagnetic radiation of high frequencies
(1017-1020 Hz). They penetrate soft tissue but are blocked by
bone etc.

6. X-rays are produced when high-speed electrons hit a
metal target. In medical x-rays this is usually tungsten.
Tungsten target
Electrons (anode)
x-rays

7. Electrons are produced by thermionic emission.
They are accelerated across the vacuum tube towards
the positive (anode) target.
The electrons strike the target and lose about 99% of
their energy in low-energy collisions with the target atoms
– this heats up the target. The remainder of the energy
reappears as x-ray radiation.
Overheating is prevented by using a rotating anode and
circulating oil. Copper is used for the anode mountings.

9. Overheating is prevented by using a rotating anode and
circulating oil. Copper is used for the anode mountings.

10. The energy exchange in x-ray production