Notes on Radioactivity videos
Title(duration) Covers Context
Science in Isotopes; nuclear notation, numbers of neutrons and protons in nucleus; unstable C-14, even mentions how C-14 turns Radio-carbon
Focus into nitrogen atom. dating of
(20 min) Cosmic rays and formation of C-14 from N-14; absorption of Co2 by plants (range of dates 50000, 200 yrs) living or Egyptian mummy
once living things; decay of C-14; good intro to T1/2; activity of C is not tested, proportion is measured using mass Treatment of
spectrometry cancer
Types of radn: nature of each; penetration in air; paper, aluminium foil, lead (shows all of gamma being stopped by
lead though)
Tracers (called technezium on the video); shows gamma camera; preparation of technetium tracer, advantages of
radioactive imaging (dynamic processes)
Cervical cancer: treatment by radiotherapy (28 sessions of LINAC X-rays, rotation of head; radioisotope treatment,
serious discussion of risks and benefits
Science bank Detection and origin: hazard symbol; Geiger Muller tube to detect (connected to counter); background count, natural Medical uses
– radioactivity background radiation (rock, tiles, watch, potassium chloride; cosmic rays); structure of atom – nucleus and electrons,
(15 min) unstable nuclei give out radiation. Becquerel’s discovery, cloud chamber showing alpha tracks; ionisation
Types and PROPERTIES: alpha, beta gamma – penetrating power beta absorbed by Al, but penetrates paper
(production of beta by neutron to proton decay); alpha stopped by few cm air, thick paper stops all – alpha 2 p 2n;
gamma – pentrates paper and Al, but reduced by lead; gamma undeflected by magnetic field
Can be used in difference ways
Half life - Hospital – tracers similar footage as sci in focus – gamma camera radiation gets out of body. Compares
kidney function. Radioactive for ever? Half life of technetium-99 – activity decreases; Ba-137 (unlabelled graph
showing half life) – leaves with Qu what will be activity of Tc-99 after 24 hrs (answer T1/2 = 6 hrs, so activity will
drop to ½ x ½ x ½ of original activity)
Short Circuit Nucleus of atom – most stable, plutonium not – alpha radn nature, prodn of beta by proton to neutron decay, gamma Police raid 1994 –
– released by rearrangement of nucleus without change. fake bank notes?
Radioactivity Background radiation – then not really explained, but goes on to alpha beta and gamma penetration ( alpha air and No – plutonium (
(20 min) paper; beta paper, Perspex(!), gamma Perspex lead reduces) needed for
Precautions gloves; luminous paint on compass; identification of radium by spectral analysis of gamma rays; nuclear bomb)
Spine curved – fracture (bone scan) - reveals detail not visible on normal X-ray – technetium generator Rower – Gavin
A- level detail of technetium cow. Radiation only strong for a few hours – slow description of T1/2. T1/2 for Tc-99 6 Hales –
hours; exposure to workers mentioned more than patients; scan 2 hrs later, gamma scan gives 3D reconstruction; 45 radioactive
min scan; increased uptake of Tc shows bone trying to heal – let fracture heal, no surgery. injection