Anti matter and matter cannot be kept together
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From: Victar Shawberger on 5 Jul 2010 05:51 On Jul 5, 3:19 am, 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, 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 In spite of that, Burt has a point The magnetic field comes from the surface atoms of the chamber How is this not an interact? If an antimatter particle touch a matter particle is the same thing, they must interact by their electromagnetic field I do not understand Burt is not right here
From: Yousuf Khan on 5 Jul 2010 07:31 On 7/5/2010 4:20 AM, BURT wrote: > On Jul 4, 2:32 pm, Jeroen Belleman<jer...(a)nospam.please> wrote: >> On 07/04/2010 10:00 PM, BURT wrote: >> >> >> >>> You can't get [positrons] in a magneitc field first because that is a matterial >>> source that it would react with on the spot. >> >> Where did you get that idea? >> >> Keeping positrons or antiprotons in electromagnetic traps works fine. > > How do they get into EM traps made of matter without anihilating? You simply don't let them touch any matter, that's all. You put them into magnetic vacuum bottles. The bottles are made of matter, of course, they are simply used to keep other matter (such as air) from wandering inside them. The magnetic fields are not made of either matter or anti-matter, they are just a force field. The magnetic fields are used to direct the charged anti-matter particles away from the walls of the vacuum bottle and into the center of the bottle completely away from the walls. They stay suspended inside the vacuum bottles by the magnetic fields. Yousuf Khan
From: Jeroen Belleman on 5 Jul 2010 07:50 Victar Shawberger wrote: > In spite of that, Burt has a point > The magnetic field comes from the surface atoms of the chamber > > How is this not an interact? > > If an antimatter particle touch a matter particle is the same thing, > they must interact by their electromagnetic field You are right that this is an interaction. The origin of the field does not matter however. An electromagnetic field is the same, irrespective of whether it was created by matter or antimatter. The em-fields of the trap are carefully tailored to keep the antimatter particles away from any material part of the trap. The concept of particles 'touching' is slippery at these scales. Also, there are other forces besides electromagnetics that make particles interact. I'm not a particle physicist however, so I will not comment on the details of annihilation reactions. But I know enough to identify a bunch of antiprotons when I see one via the instruments that I make. Regards, Jeroen Belleman
From: Yousuf Khan on 5 Jul 2010 08:31 On 7/5/2010 8:07 AM, BURT wrote: >>> 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? A particle accelerator creates them during collision events. The vacuum is very complete. It's the equivalent of the vacuum of space at 1000km above the Earth, which is 10^-10 Torr (equal to 1.333x10^-8 Pa (pascals) or 1.316x10^-13 atm (atmospheres) or 1.934x10^-12 psi (pounds-force per square inch)). "Ultrahigh beam vacuum 10-10 Torr (~3 million molecules/cm3) , we want to avoid collisions with gas molecules In space the pressure decreases with the altitude from the pressure of 760 Torr at sea level. Up to 100 km altitude (troposphere and stratosphere) the pressure decreases quite regularly by a factor of 10 per 15 km altitude, which results in a pressure of 10-3 Torr at about 90 km altitude. The ionosphere (100-400 km) contains a large number of ionized atoms, and its pressure decreases only by a factor of 10 every 100-200 km. This decrease results in a pressure of about 10-10 Torr at an altitude of 1,000 km. " http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach/components/vacuum.htm > 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? They are traveling over 99% the speed of light. They will pass through at least thousands of miles of the spaces between most of the matter before the meagre electromagnetic attraction to matter even diverts it by 1%. They were created in far stronger magnetic fields to get accelerated to >0.99c, so you need equally strong reverse magnetic fields to slow them down. The reversal slows them down enough to be captured in magnetic vacuum bottles. > - Bottom line: only the antiprotons that STOP in matter will > annihilate. > > > I challenge that. Motion doesn't stop the attraction in any way. That's right, but you have far more attraction from the generated magnetic field than you will get from the natural attraction of the matter particles nearby. Yousuf Khan
From: Yousuf Khan on 5 Jul 2010 09:05
On 7/5/2010 3:51 PM, Victar Shawberger wrote: > In spite of that, Burt has a point > > The magnetic field comes from the surface atoms of the chamber Actually the magnetic field comes from several superconducting electromagnets nearby, but not from the surface of the chamber tubes. The chamber tubes have their own natural internal electromagnetic field, which is mostly neutral from a distance. But any microscopic magnetic field they may have are overwhelmingly overpowered by the superconducting electromagnets outside their walls. > How is this not an interact? The electromagnetic field is not made of either matter or anti-matter, it is just a force field. The electromagnetic field is carried by photons. Photons (i.e. particles of light) are the force carrier particle for electromagnetism. Photons are neither matter or anti-matter, they are just energy. Photons coming from anti-matter are exactly the same as photons from matter. > If an antimatter particle touch a matter particle is the same thing, > they must interact by their electromagnetic field > > I do not understand Burt is not right here I see where the confusion is here. You are thinking that because we say that anti-matter particles have the exact opposite electrical charge as their matter counterparts, that must be the reason why they annihilate? That is, a proton is positive while an anti-proton is negative. If that was the only reason why particles annihilate, then electrons would've annihilated protons billions of years ago, because they too have exactly the opposite electrical charge as each other. The opposite charges between matter and anti-matter counterparts is just one of many properties that are reversed between them. Actually it's probably the most superficial property, but it's the easiest one to remember about. The electromagnetic field might pull them close to each other through their charge attractions. The electromagnetic force works only over long distances, but it has no effect within the space of an atomic nucleus. At a far lower level, what really annihilates these two particles is when they are close enough to interact via the Strong and Weak nuclear forces. The nuclear forces only act over the distances of an atomic nucleus. It's the Strong and Weak nuclear forces that really makes the two particles interact and annihilate each other. Yousuf Khan |