Positron decay dynamics for radioactive Carbon-11 as predicted by the Brightsen Model
From the following web site (www.amersham.com) the process of "beta decay" is explained:
"Type of radioactive decay in which a nucleus ejects a beta particle, either an electron or a positron. In a beta (-) decay a neutron gets converted into a proton and an electron. Hence, the atomic number of the nucleus increases by one, the number of nucleons stays constant and the electron leaves the nucleus as a beta (-) particle. In a beta (+) or positron decay a proton is converted into a neutron and a positron or beta (+) particle, which leaves the nucleus. The atomic number of the nucleus thus decreases by one, while the number of nucleons stays constant. Beta (-) decays are favored in small radioactive nuclei when atoms have an excess of neutrons relative to protons, while beta (+) decays are favored when the "mother" nuclide has an excess of protons relative to neutrons."
It is well known that beta (+) or positron decay is a property of the radioactive isotope Carbon-11. A common use of 11C6 in medical research is in Positron Emission Tomography (PET). Because 11C6 has 6 protons and 5 neutrons, beta (+) decay is favored over beta (-) decay. PET is based on a simple principle that the positron (beta +) emitted from carbon-11 joins with a electron (-) from human tissue to yield gamma rays which are detected by the PET scanner (see this link: http://science.howstuffworks.com/nuclear-medicine2.htm)
In his 1995 letter to Fusion Facts (see Publications) Mr. Brightsen provides one isodyne structure for 11C6 that accurately predicts its observed beta (+) decay dynamics due to excess protons in the form of an unstable di-proton cluster [P-P] as follows:
Cluster Structure of Carbon-11 as Predicted by the Brightsen Model:
A = 2 Clusters A=3 Clusters
NN NP PP NPN PNP Core structure
0 0 1 2 1 9Be4
From the above nucleon cluster structure it is clear that the positron decay observed in radioactive 11C6 can result from the unstable [P-P] cluster undergoing beta (+) decay to form a very stable [N-P] cluster + the emission of the positron (beta +) used in PET medical research. The outcome of this decay process is the formation of the stable isotope 11B5
Mr. Brightsen also indicates in his paper that a bound core 9Be4structure of { [N-P-N] + {P-N-P] + [N-P-N] } exists within 11C6. Because 9Be4 is known to be a stable structure, it cannot be the source of the positron decay observed in radioactive 11C6.
The above isodyne structure for 11C6 predicted by the Brightsen Model also accurately predicts the known I=3/2 spin for 11C6 as the summation of I = 3/2 spin for the stable 9Be4 core, plus I = 0 spin for coupled [P-P] cluster (see this Link)
Note: As explained by the two links below, the "dynamics" of positron (beta +) decay is not identicle to "electron capture", although both processes can result in identicle daughter nuclides from a parent and the transformation of a "proton" into a "neutron".
For dynamics of "electron capture" see this link: http://www.courses.vcu.edu/PHYS320/pdf/8Nuclear041.ppt#19
For dynamics of "beta + positron decay" see this link: http://www.courses.vcu.edu/PHYS320/pdf/8Nuclear041.ppt#18
