year 11 physics ionising radiation & nuclear reactions topic test, dosimetry & nuclear medicine E&A validation review | errors
part 1
question 1
b) how does the completed equation demonstrate that this isotope would be suitable for instigating a chain reaction
because it can undergo nuclear fission -1
more than one neutron is released as a result of the fission of the nuclide
c)
calculator error, equation F.T was correct, somehow misread a 9 as an 8 :( -1
question 3
- revise nuclear reactor parts - moderator / control rods -2
- moderator
- u235 absorbs neutrons more efficiently when their speed is slower
- the purpose of a moderator is to slow down the speed of the neutrons released by fission reactions
question 5
- use nuclear atomic mass values to find atomic mass (????) -1
part 2
question 2
- briefly explain how ionising radiation kills cancer cells. -3
- ionising radiation ionises atoms by removing electrons (1). This affects the composition of the compound in the cell which affects cellular processes (1). cancer cells are unable to repair themselves and hence they die (1)
question 3
- briefly outline the structure and function of a gamma camera with specific reference to the collimator, scintillation crystal and photomultiplier tubes. -3
- a radionuclide is administered to the patient and emits gamma rays
- the collimator limits absorption of emitted rays to those travelling parallel to the collimator plates (thus improving resolution of the image)
- the scintillation crystal detects the gamma rays and produces flashes of (visible light)
- the light flashes are detected by the photo multiplier tubes and converted into an electrical signal
- the electrical signals are used to construct an image based on the distribution of the radionuclide in the patient’s body
question 4
- needed 1 more point on difference between neutron therapy and ionising radiation therapy. -1
question 5
- explain the term dose equivalent
- need to explain what properties affects the dose equivalent’s quality factor (i think its ionisation level?) -1
question 6
- a) need units for absorbed dose -1
question 7
- cyclotron (1)
- need 1 more: -1
- synchrotron
- nuclear reactor
- proton accelerators