What type of radioactive decay is carbon dating
To perform a PET scan, a positron-emitting radioisotope is produced in a cyclotron and then attached to a substance that is used by the part of the body being investigated.This “tagged” compound, or radiotracer, is then put into the patient (injected via IV or breathed in as a gas), and how it is used by the tissue reveals how that organ or other area of the body functions. A PET scanner (a) uses radiation to provide an image of how part of a patient’s body functions.The beta particle (electron) emitted is from the atomic nucleus and is not one of the electrons surrounding the nucleus. Emission of an electron does not change the mass number of the nuclide but does increase the number of its protons and decrease the number of its neutrons.Consequently, the n:p ratio is decreased, and the daughter nuclide lies closer to the band of stability than did the parent nuclide.The scans it produces can be used to image a healthy brain (b) or can be used for diagnosing medical conditions such as Alzheimer’s disease (c).(credit a: modification of work by Jens Maus)O () and incorporated into a glucose analog called fludeoxyglucose (FDG).Electron capture has the same effect on the nucleus as does positron emission: The atomic number is decreased by one and the mass number does not change.
Beta particles, which are attracted to the positive plate and deflected a relatively large amount, must be negatively charged and relatively light.
Whether electron capture or positron emission occurs is difficult to predict.
The choice is primarily due to kinetic factors, with the one requiring the smaller activation energy being the one more likely to occur.
Gamma rays, which are unaffected by the electric field, must be uncharged. Because the loss of an α particle gives a daughter nuclide with a mass number four units smaller and an atomic number two units smaller than those of the parent nuclide, the daughter nuclide has a larger n:p ratio than the parent nuclide.
If the parent nuclide undergoing α decay lies below the band of stability (refer to Chapter 21.1 Nuclear Structure and Stability), the daughter nuclide will lie closer to the band.
Ernest Rutherford’s experiments involving the interaction of radiation with a magnetic or electric field (Figure 2) helped him determine that one type of radiation consisted of positively charged and relatively massive α particles; a second type was made up of negatively charged and much less massive β particles; and a third was uncharged electromagnetic waves, γ rays.