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Where does the positron produced during positron emission come from?
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What is a positron?
A positron is a positively charged electron. It's an antielectron - antimatter! The positron has a charge of +1 (just the opposite of the -1 of the electron), and a spin of 1/2 as an electron does. The mass of this elementary particle is about 9.103826 x 10-31 kg. The actual charge on this particle is about +1.602 x 10-19 coulombs. We write it as β+ or e+ in nuclear equations. It was Paul Dirac who first theorized that it may exist back in 1928, and in 1932, Carl D. Anderson discovered and named the positron. How was it done? By allowing cosmic rays to pass through a cloud chamber shielded with lead and set up in a magnetic field, the electron-positron pairs that were sometimes created could be observed. Once created, the particles moved (curved) in opposite directions within the magnetic field. Simple and clever! It should be noted that Caltech graduate student Chung-Yao Chao is credited with detecting the positron in 1930, but he was unable to explain it. We should also note that the positron is emitted (positron emission) in beta plus decay, which is a form of radioactive decay. Pair production, the "conversion" of electromagnetic energy into a positron and an electron, is also a source of positrons. Regardless of the source, the positron will always seek to "combine" with any nearby electron with the mass of both particles being converted into electromagnetic energy (a pair of gamma rays). A more detailed description and some of the other characteristics of the positron can be found in the Wikipedia article on that subject. A link is provided below to that post and also to some Related questions that will aid in understanding this critter.
Why are positrons produced from some nuclei but alpha or beta radiation come from other nuclei?
Positrons are a type of beta radiation (along with electons). Let's check things out to figure out why some nuclei are positron emitters. Positron emission (beta + decay) follows after the conversion of a neutron in an atomic nucleus into a proton. In atomic nuclei that have an excess number of neutrons to be stable, this is a common form of decay. It directly assists an unstable nucleus in getting closer to the "line of stability" of the N-Z plot. As beta + decay has a higher probablity for nuclei with excessive numbers of neutrons, beta - decay has a higher probability for nuclei with shortages of neutrons. In general, alpha decay is reserved for the heaviest radionuclides. We see radium, uranium, plutonium and a number of other elements from the upper end of the periodic table as having alpha decay as a possibility among their methods of decay. Links can be found below.
What is pair production?
Pair production is the transformation of electromagnetic energy into matter, into a particle and its antiparticle, usually an electron and a positron. Let's have a look at this situation. When a high energy gamma ray with a minimum energy of 1.022 MeV passes close to an atomic nucleus, a phenomenon called pair production can occur. In this event, the energy of the gamma ray is converted into mass. It's a play right out of Albert Einstein's quantum mechanical playbook. The electron and positron are opposites of each other, and the appearance of an elementary particle and its antiparticle must obey conservation laws. That's where the "assistance" of a nearby atomic nucleus comes in. The electron and positron will appear and come away from the event with some given kinetic energy, and will scatter and slow down as they move off. The positron, of course, will end up combining with an electron in a mutual annihilation event where the two particles have their mass entirely converted into energy. This will result in a pair of electromagnetic rays, or photons, leaving the annihilation event and moving in opposite directions.
Are beta particles are electrons detached from the nucleus?
During nuclear decay when a beta- particle (a high energy electron coming from the decay event) leaves the nucleus, the action is the result of the transformation of a neutron into a proton and an electron (the beta- particle). Got links if you want them. They are to related articles posted by our friends at Wikipedia, where knowledge is free. Note: there is a bit more to beta decay than was mentioned here, but enough was presented to answer the question. Certainly it is hoped that the links will extend knowledge about as far as the average reader may wish to go.
Where does the particle photon come from?
A photon may be both a particle and a wave (light). Photons are normally emitted when an electron loses energy either by bending its path or by falling from a higher orbital state to a lower orbital state. Very high energy photons called gamma ray can also be formed from a positron and and electron merging.
Why is the positron emitter more than beta emitter in medium nuclei?
Electrons being negatively charged will be attracted by the protons within the nucleus and so they come after spending energy against the force of attraction. But positron being positively charged will be repelled by positively charged portons. Hence the energy difference between electron and positron emission in case of beta decay
Does atomic emission come from the sun?
there is no atomic emission from the sun.
Is a cat scan nuclear fusion or nuclear fission?
Neither, a CAT scan is one where computers are used to synthesise an image, but the radiation used is usually X-rays, though positron emission can be used, in this case it will be using appropriate radiation sources. Fusion and fission don't come into it.
What is a positron?
A positron is a positively charged electron. It's an antielectron - antimatter! The positron has a charge of +1 (just the opposite of the -1 of the electron), and a spin of 1/2 as an electron does. The mass of this elementary particle is about 9.103826 x 10-31 kg. The actual charge on this particle is about +1.602 x 10-19 coulombs. We write it as β+ or e+ in nuclear equations. It was Paul Dirac who first theorized that it may exist back in 1928, and in 1932, Carl D. Anderson discovered and named the positron. How was it done? By allowing cosmic rays to pass through a cloud chamber shielded with lead and set up in a magnetic field, the electron-positron pairs that were sometimes created could be observed. Once created, the particles moved (curved) in opposite directions within the magnetic field. Simple and clever! It should be noted that Caltech graduate student Chung-Yao Chao is credited with detecting the positron in 1930, but he was unable to explain it. We should also note that the positron is emitted (positron emission) in beta plus decay, which is a form of radioactive decay. Pair production, the "conversion" of electromagnetic energy into a positron and an electron, is also a source of positrons. Regardless of the source, the positron will always seek to "combine" with any nearby electron with the mass of both particles being converted into electromagnetic energy (a pair of gamma rays). A more detailed description and some of the other characteristics of the positron can be found in the Wikipedia article on that subject. A link is provided below to that post and also to some Related questions that will aid in understanding this critter.
Where do the oxigens atoms in the O2 produced during photosynthesis come from?
It is produced from water. Water is broken down by photolysis to get electrons.
Why does the emission light come on in a car?
Have vehicle scanned to determine the problem
What is the difference between effluents and emission?
Effluents are liquid waste that come out of industrial pipeline while emission the act or process of letting something out or giving something out
What is the difference between a positron and an electron?
An electron is the carrier of the negative electrostatic force, and it has a charge of -1. Also, the electron, along with the proton and neutron, are the "basic building blocks" of atoms, and they make up the matter all around us. The positron, on the other hand, is an anti-electron - it's antimatter! And it is the antiparticle of the electron. It has a charge of +1, which is just the opposite of the electron's. The fact that the electron and positron are matter and anti-matter, and that they have a charge of -1 and +1 respectively are the major differences. A positron is an electron's anti-particle, and when the electron and positron come in contact with each other to combine, they annihilate each other in a process called electron-positron annihilation. There is a link below to that related question and to a couple of others.
How do you repair the manufacturer auxiliary emission control system in a 2001 Chevy Malibu?
Begin by removing the wiring harness. Remove the retaining screws. The emission control will come off. Reverse the process to install your new emission control.
What gives Swiss cheese wholes?
The wholes in Swiss Cheese come from gases produced by bacteria during the production of the cheese.
Can a female urinate during intercourse?
yes but the urine will not come out through the vagina. Some fetishii are produced upon this fact
Where did positrons come from?
Where did they come from? They weren't invented they've always been around the positron is a fundamental part of this universe, it is the antiparticle to the electron and is found in many reactions throughout the universe. If you mean how are they created? they can be created in many ways but a common method is a nuclear reaction called a 'Beta Positive Decay' where a Proton decays into a Neutron Positron and neutrino P --> n + e(+) + v
