ahrkron said:I think this is crackpot material.
Astronuc said:IMO, this is rather impractical since anti-matter production rates are extremely low (IIRC < pico-grams/yr) so it would take roughly >1000 years to get on the order of nano-grams - and that would have to be anti-hydrogen of some form.
IIRC, there is not satisfactory storage system for any quantity of molecular antihydrogen. This would require bringing anti-protons and positrons to rest in a magnetic container - in molecular form.
from http://gltrs.grc.nasa.gov/reports/2001/CR-2001-211116.pdf [Broken] pdf file (click on to open or save target as)The two leading facilities for antiproton production and storage are the European Laboratory for Particle Physics (formerly CERN, the Center for European Nuclear Research) in Geneva, and the Fermi National Accelerator Laboratory (FNAL) in the United States. At the CERN facility, protons are accelerated by a linear accelerator to 50 MeV (8x10-12 J), injected into a booster ring and accelerated to 800 MeV, and then sent to a proton synchrotron, where they are further accelerated to 26 GeV. The high-energy protons are then focused into a 2-mm beam and directed into a 3-mm diameter, 11-cm long copper wire target. The relativistic protons collide with the target nuclei, producing a spray of gammas, pions, kaons, and baryons, including antiprotons. On leaving the target, the antiprotons have a peak momentum of 3.5 GeV/c, corresponding to a peak energy of roughly 3 GeV. A short focal length, pulsed magnetic horn is used to capture antiprotons that have momenta within 1.5% of their peak value, at angles up to 50 mrad from the target centerline. The captured antiprotons are sent to a storage ring in bursts of about 107 antiprotons every few seconds, and around 1011 antiprotons can be accumulated before space charge effects scatter the circulating beam. The antiprotons are sent back to the proton synchrotron, which decelerates them to an energy of 200 MeV, and then to the low energy antiproton ring, where the circulating beam is further decelerated, stochastically cooled, and stored. Similar techniques are used to create antiprotons at FNAL.
from Antimatter production - Wikipedia. See also Antimatter as fuel on same webpage.Scientists in 1995 succeeded in producing anti-atoms of hydrogen, and also antideuteron nuclei, made out of an antiproton and an antineutron, but no anti-atom more complex than antideuterium has been created yet. In principle, sufficiently large quantities of antimatter could produce anti-nuclei of other elements, which would have exactly the same properties as their positive-matter counterparts. However, such a "periodic table of anti-elements" is thought to be, at best, highly unlikely, as the quantities of antimatter required would be, quite literally, astronomical.
Antiparticles are created elsewhere in the universe where there are high-energy particle collisions, such as in the center of our galaxy, but none have been detected that are residual from the Big Bang, as most normal matter is . The unequal distribution between matter and antimatter in the universe has long been a mystery. The solution likely lies in the violation of CP-symmetry by the laws of nature, see baryogenesis.
Positrons and antiprotons can individually be stored in a device called a Penning trap, which uses a combination of magnetic field and electric fields to hold charged particles in a vacuum. Two international collaborations (ATRAP and ATHENA) used these devices to store thousands of slowly moving antihydrogen atoms in 2002. It is the goal of these collaborations to probe the energy level structure of antihydrogen to compare it with that of hydrogen as a test of the CPT theorem. One way to do this is to confine the anti-atoms in an inhomogenous magnetic field (one cannot use electric fields since the anti-atom is neutral) and interrogate them with lasers. If the anti-atoms have too much kinetic energy they will be able to escape the magnetic trap, and it is therefore essential that the anti-atoms are produced with as little energy as possible. This is the key difference between the antihydrogen that ATRAP and ATHENA produced, which was made at very low temperatures, and the antihydrogen produced in 1995 which was moving at a speed close to the speed of light.
Antimatter/matter reactions have practical applications in medical imaging, see Positron emission tomography (PET). In some kinds of beta decay, a nuclide loses surplus positive charge by emitting a positron (in the same event, a proton becomes a neutron, and neutrinos are also given off). Nuclides with surplus positive charge are easily made in a cyclotron and are widely generated for medical use.
Rade said:I have a question. From the link cited above: http://gltrs.grc.nasa.gov/reports/2001/CR-2001-211116.pdf [Broken]
I read that at CERN, 26GeV "protons" (with quark structure uud) are made to collide with a copper wire (having very complex quark structure). The collision thus produces "antiprotons" (with quark structure u^u^d^, where ^ = symbol for antiquark)
My question is, from where does the (u^u^d^) come from that is observed in this collision, the "proton", the "copper", both, or neither ? That is, how can two "matter" entities form "antimatter" ? Thanks for any help you can provide.
Rade said:Thank you Spin Network -- clearly the antimatter observed is a "by-product" of "certain events"-- but this does not answer my question.
I wish to know the "dynamics" of the "certain event(s)" -- i.e., what model of nuclear physics explains how the antimatter is formed ? -- it has to be one of these logical possibilities:(1) the antimatter observed derives from the proton projectile, (2) the antimatter derives from the copper target, (3) it derives from a quark combination of both projectile + target, (4) it derives from neither projectile nor target. Are we saying that QCD and the Standard Model cannot explain the "dynamics" ? My interest in this question derives from the possibility that the "antiproton" exists as a parton quark structure within the proton projectile.