Why don't we use positrons from beta plus radiation as a source of anti-electrons for energy?
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Why can't we use the positrons (let off by beta plus radiation) as a source of anti-matter, such that we can collide it with an electron for 100% efficient mass to energy conversion?
particle-physics energy-conservation radiation antimatter
asked Nov 6 at 14:40
Harvey Stanfield
434
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up vote
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Why can't we use the positrons (let off by beta plus radiation) as a source of anti-matter, such that we can collide it with an electron for 100% efficient mass to energy conversion?
particle-physics energy-conservation radiation antimatter
asked Nov 6 at 14:40
Harvey Stanfield
434
3
Well, when the positron and electron recombine, you get some high energy photons out that are generally speaking hard to convert to human-usable energy forms.
– Jon Custer
Nov 6 at 15:01
add a comment |
up vote
6
down vote
favorite
up vote
6
down vote
favorite
Why can't we use the positrons (let off by beta plus radiation) as a source of anti-matter, such that we can collide it with an electron for 100% efficient mass to energy conversion?
particle-physics energy-conservation radiation antimatter
asked Nov 6 at 14:40
Harvey Stanfield
434
Why can't we use the positrons (let off by beta plus radiation) as a source of anti-matter, such that we can collide it with an electron for 100% efficient mass to energy conversion?
particle-physics energy-conservation radiation antimatter
particle-physics energy-conservation radiation antimatter
asked Nov 6 at 14:40
Harvey Stanfield
434
asked Nov 6 at 14:40
Harvey Stanfield
434
asked Nov 6 at 14:40
Harvey Stanfield
434
asked Nov 6 at 14:40
Harvey Stanfield
434
asked Nov 6 at 14:40
Harvey Stanfield
434
434
3
Well, when the positron and electron recombine, you get some high energy photons out that are generally speaking hard to convert to human-usable energy forms.
– Jon Custer
Nov 6 at 15:01
add a comment |
3
Well, when the positron and electron recombine, you get some high energy photons out that are generally speaking hard to convert to human-usable energy forms.
– Jon Custer
Nov 6 at 15:01
3
3
Well, when the positron and electron recombine, you get some high energy photons out that are generally speaking hard to convert to human-usable energy forms.
– Jon Custer
Nov 6 at 15:01
Well, when the positron and electron recombine, you get some high energy photons out that are generally speaking hard to convert to human-usable energy forms.
– Jon Custer
Nov 6 at 15:01
add a comment |
3 Answers
3
active
oldest
votes
up vote
15
down vote
accepted
The important number is not the efficiency of the conversion of mass to energy. Instead, what you should be looking at is the efficiency of the conversion of the resulting gamma radiation to electric current. This conversion has never been particularly efficient, since generating a usable electric current typically involves giving a large number of electrons each a little bit of energy, while radiation (especially ionizing radiation like gamma rays) tends to give a small number of electrons each a lot of energy. Of course, the latter can lead to the former, but only once the few energetic electrons collide with many other electrons. This may produce a current, with the right setup, but it will also produce heat, as the energy absorbed by the initial electrons is dissipated in the random motion of the electrons around them. The production of heat means that the conversion process is not perfectly efficient.
answered Nov 6 at 15:02
probably_someone
15.2k12554
add a comment |
up vote
6
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Beta plus decay is one of the possible decays in radioactive materials. To get just positrons would mean one would have to produce materials that decay into positrons,i.e. spend energy in doing that.
Positron decay is given by various isotopes , which are not found in great reserves so as to be useful in producing energy by the gamma rays given off the annihilation of the positrons on electrons.
Radioactivity has been harnessed in radioisotope thermoelectric generators :
A radioisotope thermoelectric generator, or RTG, uses the fact that radioactive materials (such as plutonium) generate heat as they decay into non-radioactive materials. The heat used is converted into electricity by an array of thermocouples which then power the spacecraft.
answered Nov 6 at 16:42
anna v
154k7148442
2
FWIW, most of the isotopes in that list have short half-lives, so when they're used for PET they are made on-site. Obviously, that would be impractical if you want to use them for energy storage. ;) Al-26 has a relatively long half-life (717,000 years), but (as usual) the long half-life is correlated with low energy of the emitted particle, so it tends to decay via electron capture rather than positron emission, and K-40 is even worse in that regard, with its longer half-life, plus extra decay modes.
– PM 2Ring
Nov 6 at 17:53
add a comment |
up vote
2
down vote
We do. Systems that do this are called betavoltaics.
answered Nov 6 at 22:31
Big Mike Cavendish
271
1
Betavoltaics use electrons, they do not use positrons, so they aren't relevant to this question.
– PM 2Ring
Nov 6 at 23:31
thanks for the link. I remembered the plutonium but not this.
– anna v
Nov 7 at 6:41
add a comment |
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
15
down vote
accepted
The important number is not the efficiency of the conversion of mass to energy. Instead, what you should be looking at is the efficiency of the conversion of the resulting gamma radiation to electric current. This conversion has never been particularly efficient, since generating a usable electric current typically involves giving a large number of electrons each a little bit of energy, while radiation (especially ionizing radiation like gamma rays) tends to give a small number of electrons each a lot of energy. Of course, the latter can lead to the former, but only once the few energetic electrons collide with many other electrons. This may produce a current, with the right setup, but it will also produce heat, as the energy absorbed by the initial electrons is dissipated in the random motion of the electrons around them. The production of heat means that the conversion process is not perfectly efficient.
answered Nov 6 at 15:02
probably_someone
15.2k12554
add a comment |
up vote
15
down vote
accepted
The important number is not the efficiency of the conversion of mass to energy. Instead, what you should be looking at is the efficiency of the conversion of the resulting gamma radiation to electric current. This conversion has never been particularly efficient, since generating a usable electric current typically involves giving a large number of electrons each a little bit of energy, while radiation (especially ionizing radiation like gamma rays) tends to give a small number of electrons each a lot of energy. Of course, the latter can lead to the former, but only once the few energetic electrons collide with many other electrons. This may produce a current, with the right setup, but it will also produce heat, as the energy absorbed by the initial electrons is dissipated in the random motion of the electrons around them. The production of heat means that the conversion process is not perfectly efficient.
answered Nov 6 at 15:02
probably_someone
15.2k12554
add a comment |
up vote
15
down vote
accepted
up vote
15
down vote
accepted
The important number is not the efficiency of the conversion of mass to energy. Instead, what you should be looking at is the efficiency of the conversion of the resulting gamma radiation to electric current. This conversion has never been particularly efficient, since generating a usable electric current typically involves giving a large number of electrons each a little bit of energy, while radiation (especially ionizing radiation like gamma rays) tends to give a small number of electrons each a lot of energy. Of course, the latter can lead to the former, but only once the few energetic electrons collide with many other electrons. This may produce a current, with the right setup, but it will also produce heat, as the energy absorbed by the initial electrons is dissipated in the random motion of the electrons around them. The production of heat means that the conversion process is not perfectly efficient.
answered Nov 6 at 15:02
probably_someone
15.2k12554
The important number is not the efficiency of the conversion of mass to energy. Instead, what you should be looking at is the efficiency of the conversion of the resulting gamma radiation to electric current. This conversion has never been particularly efficient, since generating a usable electric current typically involves giving a large number of electrons each a little bit of energy, while radiation (especially ionizing radiation like gamma rays) tends to give a small number of electrons each a lot of energy. Of course, the latter can lead to the former, but only once the few energetic electrons collide with many other electrons. This may produce a current, with the right setup, but it will also produce heat, as the energy absorbed by the initial electrons is dissipated in the random motion of the electrons around them. The production of heat means that the conversion process is not perfectly efficient.
answered Nov 6 at 15:02
probably_someone
15.2k12554
answered Nov 6 at 15:02
probably_someone
15.2k12554
answered Nov 6 at 15:02
probably_someone
15.2k12554
answered Nov 6 at 15:02
probably_someone
15.2k12554
15.2k12554
add a comment |
add a comment |
up vote
6
down vote
Beta plus decay is one of the possible decays in radioactive materials. To get just positrons would mean one would have to produce materials that decay into positrons,i.e. spend energy in doing that.
Positron decay is given by various isotopes , which are not found in great reserves so as to be useful in producing energy by the gamma rays given off the annihilation of the positrons on electrons.
Radioactivity has been harnessed in radioisotope thermoelectric generators :
A radioisotope thermoelectric generator, or RTG, uses the fact that radioactive materials (such as plutonium) generate heat as they decay into non-radioactive materials. The heat used is converted into electricity by an array of thermocouples which then power the spacecraft.
answered Nov 6 at 16:42
anna v
154k7148442
2
FWIW, most of the isotopes in that list have short half-lives, so when they're used for PET they are made on-site. Obviously, that would be impractical if you want to use them for energy storage. ;) Al-26 has a relatively long half-life (717,000 years), but (as usual) the long half-life is correlated with low energy of the emitted particle, so it tends to decay via electron capture rather than positron emission, and K-40 is even worse in that regard, with its longer half-life, plus extra decay modes.
– PM 2Ring
Nov 6 at 17:53
add a comment |
up vote
6
down vote
Beta plus decay is one of the possible decays in radioactive materials. To get just positrons would mean one would have to produce materials that decay into positrons,i.e. spend energy in doing that.
Positron decay is given by various isotopes , which are not found in great reserves so as to be useful in producing energy by the gamma rays given off the annihilation of the positrons on electrons.
Radioactivity has been harnessed in radioisotope thermoelectric generators :
A radioisotope thermoelectric generator, or RTG, uses the fact that radioactive materials (such as plutonium) generate heat as they decay into non-radioactive materials. The heat used is converted into electricity by an array of thermocouples which then power the spacecraft.
answered Nov 6 at 16:42
anna v
154k7148442
2
FWIW, most of the isotopes in that list have short half-lives, so when they're used for PET they are made on-site. Obviously, that would be impractical if you want to use them for energy storage. ;) Al-26 has a relatively long half-life (717,000 years), but (as usual) the long half-life is correlated with low energy of the emitted particle, so it tends to decay via electron capture rather than positron emission, and K-40 is even worse in that regard, with its longer half-life, plus extra decay modes.
– PM 2Ring
Nov 6 at 17:53
add a comment |
up vote
6
down vote
up vote
6
down vote
Beta plus decay is one of the possible decays in radioactive materials. To get just positrons would mean one would have to produce materials that decay into positrons,i.e. spend energy in doing that.
Positron decay is given by various isotopes , which are not found in great reserves so as to be useful in producing energy by the gamma rays given off the annihilation of the positrons on electrons.
Radioactivity has been harnessed in radioisotope thermoelectric generators :
A radioisotope thermoelectric generator, or RTG, uses the fact that radioactive materials (such as plutonium) generate heat as they decay into non-radioactive materials. The heat used is converted into electricity by an array of thermocouples which then power the spacecraft.
answered Nov 6 at 16:42
anna v
154k7148442
Beta plus decay is one of the possible decays in radioactive materials. To get just positrons would mean one would have to produce materials that decay into positrons,i.e. spend energy in doing that.
Positron decay is given by various isotopes , which are not found in great reserves so as to be useful in producing energy by the gamma rays given off the annihilation of the positrons on electrons.
Radioactivity has been harnessed in radioisotope thermoelectric generators :
A radioisotope thermoelectric generator, or RTG, uses the fact that radioactive materials (such as plutonium) generate heat as they decay into non-radioactive materials. The heat used is converted into electricity by an array of thermocouples which then power the spacecraft.
answered Nov 6 at 16:42
anna v
154k7148442
answered Nov 6 at 16:42
anna v
154k7148442
answered Nov 6 at 16:42
anna v
154k7148442
answered Nov 6 at 16:42
anna v
154k7148442
154k7148442
2
FWIW, most of the isotopes in that list have short half-lives, so when they're used for PET they are made on-site. Obviously, that would be impractical if you want to use them for energy storage. ;) Al-26 has a relatively long half-life (717,000 years), but (as usual) the long half-life is correlated with low energy of the emitted particle, so it tends to decay via electron capture rather than positron emission, and K-40 is even worse in that regard, with its longer half-life, plus extra decay modes.
– PM 2Ring
Nov 6 at 17:53
add a comment |
2
FWIW, most of the isotopes in that list have short half-lives, so when they're used for PET they are made on-site. Obviously, that would be impractical if you want to use them for energy storage. ;) Al-26 has a relatively long half-life (717,000 years), but (as usual) the long half-life is correlated with low energy of the emitted particle, so it tends to decay via electron capture rather than positron emission, and K-40 is even worse in that regard, with its longer half-life, plus extra decay modes.
– PM 2Ring
Nov 6 at 17:53
2
2
FWIW, most of the isotopes in that list have short half-lives, so when they're used for PET they are made on-site. Obviously, that would be impractical if you want to use them for energy storage. ;) Al-26 has a relatively long half-life (717,000 years), but (as usual) the long half-life is correlated with low energy of the emitted particle, so it tends to decay via electron capture rather than positron emission, and K-40 is even worse in that regard, with its longer half-life, plus extra decay modes.
– PM 2Ring
Nov 6 at 17:53
FWIW, most of the isotopes in that list have short half-lives, so when they're used for PET they are made on-site. Obviously, that would be impractical if you want to use them for energy storage. ;) Al-26 has a relatively long half-life (717,000 years), but (as usual) the long half-life is correlated with low energy of the emitted particle, so it tends to decay via electron capture rather than positron emission, and K-40 is even worse in that regard, with its longer half-life, plus extra decay modes.
– PM 2Ring
Nov 6 at 17:53
add a comment |
up vote
2
down vote
We do. Systems that do this are called betavoltaics.
answered Nov 6 at 22:31
Big Mike Cavendish
271
1
Betavoltaics use electrons, they do not use positrons, so they aren't relevant to this question.
– PM 2Ring
Nov 6 at 23:31
thanks for the link. I remembered the plutonium but not this.
– anna v
Nov 7 at 6:41
add a comment |
up vote
2
down vote
We do. Systems that do this are called betavoltaics.
answered Nov 6 at 22:31
Big Mike Cavendish
271
1
Betavoltaics use electrons, they do not use positrons, so they aren't relevant to this question.
– PM 2Ring
Nov 6 at 23:31
thanks for the link. I remembered the plutonium but not this.
– anna v
Nov 7 at 6:41
add a comment |
up vote
2
down vote
up vote
2
down vote
We do. Systems that do this are called betavoltaics.
answered Nov 6 at 22:31
Big Mike Cavendish
271
We do. Systems that do this are called betavoltaics.
answered Nov 6 at 22:31
Big Mike Cavendish
271
answered Nov 6 at 22:31
Big Mike Cavendish
271
answered Nov 6 at 22:31
Big Mike Cavendish
271
answered Nov 6 at 22:31
Big Mike Cavendish
271
271
1
Betavoltaics use electrons, they do not use positrons, so they aren't relevant to this question.
– PM 2Ring
Nov 6 at 23:31
thanks for the link. I remembered the plutonium but not this.
– anna v
Nov 7 at 6:41
add a comment |
1
Betavoltaics use electrons, they do not use positrons, so they aren't relevant to this question.
– PM 2Ring
Nov 6 at 23:31
thanks for the link. I remembered the plutonium but not this.
– anna v
Nov 7 at 6:41
1
1
Betavoltaics use electrons, they do not use positrons, so they aren't relevant to this question.
– PM 2Ring
Nov 6 at 23:31
Betavoltaics use electrons, they do not use positrons, so they aren't relevant to this question.
– PM 2Ring
Nov 6 at 23:31
thanks for the link. I remembered the plutonium but not this.
– anna v
Nov 7 at 6:41
thanks for the link. I remembered the plutonium but not this.
– anna v
Nov 7 at 6:41
add a comment |
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Well, when the positron and electron recombine, you get some high energy photons out that are generally speaking hard to convert to human-usable energy forms.
– Jon Custer
Nov 6 at 15:01