Ionising radiation and risk Flashcards
What are sources of radiation
Carbon 14- used to tell time of living
- uranium
- radon
- x-rays
- UV lamp (not ionizing)
- Nuclear powered batteries in satellites
What is alpha radiations typical speed
5% of C
What is alpha’s rest mass
6.646X10^-27KG
What is the charge on an alpha particle
2+
What is the ionizing ability of alpha
High - one d ionizes 1 atom
What is alpha absorbed by
paper
aluminium
cm air
What is the typical speed of beta
75% of c
What is the rest mass of beta
9.911x120^031 kg
What is the charge on a beta particle
-1
What is the ionizing ability of a beta particle
medium
What is beta absorbed by
thick aluminium
lead
1m air
What is the typical speed of gamma
C
3x10^8m/s
What is the rest mass of Gamma
0
What is the charge on gamma
0
What is the ionizing ability of gamma
low
What is gamma absorbed by
2m concrete
several cm of lead
How many joules are in one electron volt eV
1.6x10^-19 J
What is the charge on an electron
1.6x10^-19
What are Si units based on
Water
What is the equation for KE
KE=1/2mv^2
What is the si unit of energy
Joules
Why do we need two units of energy (joules and eV’s)
Some values are too small to see a change when in J
What are becqurels
The rate for how often the Geiger counter clicks, showing activity. Radioactivity of a source is measured in becqurels or curies.
What is the intensity of a gamma source measured in
roentgens
What is absorbed dose measured in
Rads or grays which are converted into rems and Sieverts
What is activity
No. of disintegrations per second. 1 Bq= 1 sec-1
What is absorbed dose
Energy absorbed per Kg of tissue. Measured in grays 1Gy= 1JKg-1
What is dose equivalent
Dose in grays x quality factors
Measured in Sieverts 1Sv=risk of 5%
Annual dose equivalent = 2mSv (approx.)
