Anti matter and matter cannot be kept together
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From: Tom Roberts on 4 Jul 2010 18:51 Jeroen Belleman wrote: > Keeping positrons or antiprotons in electromagnetic traps works fine. > Google "Penning trap" to get some idea of how this works. The real > trouble is anti-atoms: Once you have neutral atoms, the fields of > the trap can no longer hold them. That is true of a Penning trap, which relies on a combination of a uniform magnetic field and an electrostatic potential to trap charged particles; neutral atoms are not trapped at all. But an Ioffe trap can trap neutral atoms that have a magnetic moment. It does this with non-uniform magnetic fields specifically designed to hold neutral atoms. A major problem is the different acceptances of the two traps: the Penning trap typically traps charged particles with kinetic energies up yo ~15 keV. For antiprotons that is well above room temperature. The Ioffe trap, on the other hand, can only trap atoms with temperatures below a few Kelvin. So the challenge in making anti-hydrogen is to cool the antiprotons sufficiently well that after combining them with cold positrons, a reasonable fraction of the antihydrogen atoms will remain in the Ioffe trap. Both the ATRAP and ALPHA experiments at the CERN antiproton decelerator are working on this. I believe both have observed trapped anti-hydrogen atoms, at rather low levels, and that both are planning to observe the gravitational attraction between the earth and the anti-hydrogen, but not for several years. AEGIS is starting up specifically for the measurement of anti-hydrogen in gravity. Tom Roberts
From: BURT on 4 Jul 2010 19:43 On Jul 4, 3:51 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Jeroen Belleman wrote: > > Keeping positrons or antiprotons in electromagnetic traps works fine. > > Google "Penning trap" to get some idea of how this works. The real > > trouble is anti-atoms: Once you have neutral atoms, the fields of > > the trap can no longer hold them. > > That is true of a Penning trap, which relies on a combination of a uniform > magnetic field and an electrostatic potential to trap charged particles; neutral > atoms are not trapped at all. > > But an Ioffe trap can trap neutral atoms that have a magnetic moment. It does > this with non-uniform magnetic fields specifically designed to hold neutral atoms. > > A major problem is the different acceptances of the two traps: the Penning trap > typically traps charged particles with kinetic energies up yo ~15 keV. For > antiprotons that is well above room temperature. The Ioffe trap, on the other > hand, can only trap atoms with temperatures below a few Kelvin. > > So the challenge in making anti-hydrogen is to cool the antiprotons sufficiently > well that after combining them with cold positrons, a reasonable fraction of the > antihydrogen atoms will remain in the Ioffe trap. > > Both the ATRAP and ALPHA experiments at the CERN antiproton decelerator are > working on this. I believe both have observed trapped anti-hydrogen atoms, at > rather low levels, and that both are planning to observe the gravitational > attraction between the earth and the anti-hydrogen, but not for several years. > AEGIS is starting up specifically for the measurement of anti-hydrogen in gravity. > > Tom Roberts How does the anti matter get into the trap without interacting with the matter making up the trap? And how does it get through the atmosphere to be collected? If matter and anti matter are attracted I don't think we are dealing with real anti matter because it would anihilate after coming together by their mutual attraction. No. Anti matter is not real. It is just a hole in Dirac's equation. Mitch Raemsch
From: Tom Roberts on 4 Jul 2010 21:19 BURT wrote: > On Jul 4, 3:51 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: >> Jeroen Belleman wrote: >>> Keeping positrons or antiprotons in electromagnetic traps works fine. >>> Google "Penning trap" to get some idea of how this works. The real >>> trouble is anti-atoms: Once you have neutral atoms, the fields of >>> the trap can no longer hold them. >> That is true of a Penning trap, which relies on a combination of a uniform >> magnetic field and an electrostatic potential to trap charged particles; neutral >> atoms are not trapped at all. >> >> But an Ioffe trap can trap neutral atoms that have a magnetic moment. It does >> this with non-uniform magnetic fields specifically designed to hold neutral atoms. >> >> A major problem is the different acceptances of the two traps: the Penning trap >> typically traps charged particles with kinetic energies up yo ~15 keV. For >> antiprotons that is well above room temperature. The Ioffe trap, on the other >> hand, can only trap atoms with temperatures below a few Kelvin. >> >> So the challenge in making anti-hydrogen is to cool the antiprotons sufficiently >> well that after combining them with cold positrons, a reasonable fraction of the >> antihydrogen atoms will remain in the Ioffe trap. >> >> Both the ATRAP and ALPHA experiments at the CERN antiproton decelerator are >> working on this. I believe both have observed trapped anti-hydrogen atoms, at >> rather low levels, and that both are planning to observe the gravitational >> attraction between the earth and the anti-hydrogen, but not for several years. >> AEGIS is starting up specifically for the measurement of anti-hydrogen in gravity. >> >> Tom Roberts > > How does the anti matter get into the trap without interacting with > the matter making up the trap? The antiprotons are created in high vacuum, and traverse only the production target, the residual beam gas, and a total of a few microns of carbon before being trapped. The design of the trap keeps them from hitting its walls, and there is very little residual gas in the trap (~10^-11 torr). They are also cooled using electrons, but antiprotons don't interact very much at all with electrons, except electromagnetically (which is how they are cooled). In total, once they get out of the target, the probability of a given antiproton of being annihilated with all that matter is less than 1%, mostly because most of the matter (beam gas) is traversed at high energy. Note, however, than >99% are lost to other mechanisms (defocusing, hitting apertures, too high KE for the trap to hold them, etc.). The beam gas is ~10^-9 torr, but the antiprotons traverse billions of kilometers of it (v > 0.99 c, for 120 seconds) before reaching the carbon foil and the trap. Contrary to your naive notions, antiprotons can traverse a considerable amount of matter before annihilating, as long as they are moving with more than ~100 keV kinetic energy. > And how does it get through the > atmosphere to be collected? There is no atmosphere in the high-vacuum beam pipe. > If matter and anti matter are attracted I > don't think we are dealing with real anti matter because it would > anihilate after coming together by their mutual attraction. That is OUTRAGEOUSLY naive. Look up the pbar-p total cross-section as a function of incident energy, and compare to the related p-p cross-section. For incident energies above a few hundred keV, they are essentially the same. Below that the pbar-s do indeed annihilate (and thus have a much larger total cross-section than protons). The "attraction" you mention is purely electromagnetic, for bare particles (not atoms), and is ineffective above kinetic energies of a few keV. Bottom line: only the antiprotons that STOP in matter will annihilate. As long as they keep moving faster than ~0.001 c, they do not annihilate. But they lose energy due to ionization energy loss, so there is a limit to how much matter than can traverse. > No. Anti matter is not real. It is just a hole in Dirac's equation. Obvously you have no relevant experience or knowledge. It appears that essentially all of modern physics is just a hole in your understanding. Those of us who have relevant experience do know that anti-matter exists. It is difficult to produce and evanescent here on earth, but it most definitely exists. Tom Roberts
From: BURT on 4 Jul 2010 22:07 On Jul 4, 6:19 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > BURT wrote: > > On Jul 4, 3:51 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > >> Jeroen Belleman wrote: > >>> Keeping positrons or antiprotons in electromagnetic traps works fine. > >>> Google "Penning trap" to get some idea of how this works. The real > >>> trouble is anti-atoms: Once you have neutral atoms, the fields of > >>> the trap can no longer hold them. > >> That is true of a Penning trap, which relies on a combination of a uniform > >> magnetic field and an electrostatic potential to trap charged particles; neutral > >> atoms are not trapped at all. > > >> But an Ioffe trap can trap neutral atoms that have a magnetic moment. It does > >> this with non-uniform magnetic fields specifically designed to hold neutral atoms. > > >> A major problem is the different acceptances of the two traps: the Penning trap > >> typically traps charged particles with kinetic energies up yo ~15 keV. For > >> antiprotons that is well above room temperature. The Ioffe trap, on the other > >> hand, can only trap atoms with temperatures below a few Kelvin. > > >> So the challenge in making anti-hydrogen is to cool the antiprotons sufficiently > >> well that after combining them with cold positrons, a reasonable fraction of the > >> antihydrogen atoms will remain in the Ioffe trap. > > >> Both the ATRAP and ALPHA experiments at the CERN antiproton decelerator are > >> working on this. I believe both have observed trapped anti-hydrogen atoms, at > >> rather low levels, and that both are planning to observe the gravitational > >> attraction between the earth and the anti-hydrogen, but not for several years. > >> AEGIS is starting up specifically for the measurement of anti-hydrogen in gravity. > > >> Tom Roberts > > > How does the anti matter get into the trap without interacting with > > the matter making up the trap? > - The antiprotons are created in high vacuum, How are they created there? How high is the vacuum? I say that they have to react to matter at the very beginning and will anihilate before we could use them. Can you prove otherwise? > and traverse only the production > target, the residual beam gas, and a total of a few microns of carbon before > being trapped. The design of the trap keeps them from hitting its walls, and > there is very little residual gas in the trap (~10^-11 torr). They are also > cooled using electrons, but antiprotons don't interact very much at all with > electrons, except electromagnetically (which is how they are cooled). In total, > once they get out of the target, the probability of a given antiproton of being > annihilated with all that matter is less than 1%, mostly because most of the > matter (beam gas) is traversed at high energy. Note, however, than >99% are lost > to other mechanisms (defocusing, hitting apertures, too high KE for the trap to > hold them, etc.). > > The beam gas is ~10^-9 torr, but the antiprotons traverse billions > of kilometers of it (v > 0.99 c, for 120 seconds) before reaching > the carbon foil and the trap. > > Contrary to your naive notions, antiprotons can traverse a considerable amount > of matter before annihilating, as long as they are moving with more than ~100 > keV kinetic energy. > > > And how does it get through the > > atmosphere to be collected? > > There is no atmosphere in the high-vacuum beam pipe. > > > If matter and anti matter are attracted I > > don't think we are dealing with real anti matter because it would > > anihilate after coming together by their mutual attraction. > > That is OUTRAGEOUSLY naive. Look up the pbar-p total cross-section as a function > of incident energy, and compare to the related p-p cross-section. For incident > energies above a few hundred keV, they are essentially the same. Below that the > pbar-s do indeed annihilate (and thus have a much larger total cross-section > than protons). The "attraction" you mention is purely electromagnetic, for bare > particles (not atoms), and is ineffective above kinetic energies of a few keV. > - Bottom line: only the antiprotons that STOP in matter will annihilate. I challenge that. Motion doesn't stop the attraction in any way. >As long > as they keep moving faster than ~0.001 c, they do not annihilate. But they lose > energy due to ionization energy loss, so there is a limit to how much matter > than can traverse. > > > No. Anti matter is not real. It is just a hole in Dirac's equation. > > Obvously you have no relevant experience or knowledge. It appears that > essentially all of modern physics is just a hole in your understanding. Those of > us who have relevant experience do know that anti-matter exists. It is difficult > to produce and evanescent here on earth, but it most definitely exists. > > Tom Roberts- Hide quoted text - > > - Show quoted text - No. Anti matter is mistaken math. Mitch Raemsch
From: Jeroen Belleman on 5 Jul 2010 03:02
BURT wrote: > > No. Anti matter is mistaken math. You'll have to explain then what it is that runs through our accelerators here at CERN, which has mass like a proton, but opposite charge... Jeroen Belleman |