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16 Cards in this Set

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What is the most important electron shell?

The k-shell. The removal of electrons from the k-shell is one way in which x-rays are created.

How are electron shells labeled?

K through Q with k closest to the nucleus, the smallest, the least electrons, and the highest binding energy.

Ionization

The process of a neutral atom gaining or losing an electron. X-rays cause ionization in the atoms of the human body which causes the negative effects of radiation.

Ionizing radiation

Radiation with wavelengths shorter than 1nm which has sufficient energy to remove an electron from its atomic orbit.

Photon

Smallest possible unit of electromagnetic energy

Sine wave velocity

Wavelength x frequency = velocity, all electromagnetic radiation travels at 186,000 miles/sec.

Current

The quantity of electrons flowing in a circuit. Measured in Amperes, A, these units measure the rate, volume, or current flow in the circuit.

Potential Difference

The force or speed of the electron flow in the current. Measured in volts, V.

Household circuits

Operate at around 120V and 15 to 30 Amps

X-ray Tube Circuits

Operate at 40,000 to 125,000 volts (much higher than household) and 0.025 to 0.5 amps (much lower than household use) so we use mA (milliamps) and kVp (kilovoltpeak) instead.

Direct Current

Current flows in one direction from negative cathode to the positive anode.

Alternating Current

Changes directions (polarity) at a particular frequency measured in Hertz. In the US and Canada it is generally 60 Hz or 60 cycles per second. An impulse is half of a cycle, so at 60 Hz there would be 120 impulses.

Rectification

Changing alternating Current so that it flows in one direction only. Rectified DC is pulsating rather than constant like a battery.

Step up Transformer

Has more windings on the secondary (output) side than on the primary (input) side. Multiply the input voltage by the transformer ratio. Ex: 200V in and 500 secondary turns for each primary turn = 500:1 ratio, 200x500=100,000V or 100kVp.

Step Down Transformer

Fewer windings on the secondary (output side) than on the primary (input side) used in xrays to reduce amperage down to milliamps.

Relationship between kVp and mA in a transformer

Inverse relationship