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Topic: Antiproton

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  Antiproton Cell Experiment: Antimatter is a Better Killer - Medgadget - www.medgadget.com
Researchers sent a beam of protons or antiprotons with a range of 2 cm depth into one end of the tube, and evaluated the fraction of surviving cells after irradiation along the path of the beam.
When comparing a beam of antiprotons with a beam of protons that cause identical damage at the entrance to the target, the experiment found the damage to cells inflicted at the end of the beam path to be four times higher for antiprotons than for protons.
Antiprotons are antimatter; they have to be produced in small amounts in a laboratory with the help of a particle accelerator.
www.medgadget.com /archives/2006/11/antiproton_cell.html   (581 words)

  Antiproton - Memory Alpha, the Star Trek Wiki
An antiproton is the antimatter counterpart of a proton.
On Earth, the antiproton's existence was theorized in the 1930s, and the particle itself was discovered in 1955, a Nobel prize-winning achievement.
The Delta Rana warship used jacketed beams of antiprotons and positrons as its main weapon and fired beams with a firepower of forty megawatts and later four hundred gigawatts at the USS Enterprise-D.
memory-alpha.org /en/wiki/Antiproton   (258 words)

 Origins: CERN: Tools: Antiproton Decelerator
The antiprotons arrive at the AD like a blast from a garden hose, scattered in various directions and moving at different speeds.
This is done with the help of a method called "stochastic cooling." With stochastic cooling, measurements of the beam are taken on one side of the ring, and sent across the middle of the ring in time to make adjustments to the AD before the beam comes around the bend from the other side.
First, the antiprotons are slowed from 3.57 GeV/c to 2 GeV/c by using radio frequency electric fields.
www.exploratorium.edu /origins/cern/tools/ad.html   (573 words)

 Unique Atomic Spectroscopy aims at answering a universal question. (Atomic). - HighBeam Encyclopedia
Protons and antiprotons are used as probes to investigate the structure of matter and antimatter, which is one reason that particle accelerators such as Fermilab (Argonne, IL) and CERN create high-energy particle beams and observe the products of their collision with various targets.
The antiproton total magnetic moment is a function of both angular momentum quantum number and spin quantum number, where the angular momentum depends on orbital characteristics, while spin refers to the intrinsic magnetic moment of the respective particles.
The first laser pulse, triggered by the arrival of a packet of antiprotons into the helium target chamber, is tuned to excite a transition from a specific SHFS pair of a metastable level to a short-lived level.
www.encyclopedia.com /doc/1G1-97114802.html   (2260 words)

 FermiNews - August 20, 1999
The antiproton is the cue ball, losing its energy; the electrons are the other billiard balls, absorbing bits of energy with each collision.
The antiproton beam is densest in the center, but has thin tails extending from it.
The antiproton beam also passes through only a small segment of the bending magnet and barely feels the effects of the weak magnetic field used to inject and extract the electron beam.
www.fnal.gov /pub/ferminews/ferminews99-08-20/p4_direct.html   (944 words)

 Antiproton beam - Memory Alpha, the Star Trek Wiki
An antiproton beam is a confined beam of antiprotons.
However, Thomas Riker, commanding the captured vessel, was able to negate the beam by adjusting the resonance frequency of the cloaking device.
In an alternate timeline, Doctor Phlox used a focused antiproton beam to eliminate interspatial parasites in the brain of Jonathan Archer.
www.memory-alpha.org /en/wiki/Antiproton_beam   (159 words)

 The Antimatter Factory - What is the AD?
The Antiproton Decelerator is a very special machine compared to what already exists at CERN and other laboratories around the world.
Its task was to produce and accumulate high energy antiprotons to feed into the SPS in order to transform it into a "proton-antiproton collider".
Antiprotons accumulated in the AA were extracted, decelerated in the PS and then injected into LEAR for further deceleration.
livefromcern.web.cern.ch /livefromcern/antimatter/factory/AM-factory01.html   (243 words)

 Accelerator Details: the Antiproton Source
The antiprotons have velocity very close to the velocity of light independent of their energy.
The RF decelerates the recently injected pulses of antiprotons from the injection energy to the edge of the "stack tail." The stack tail momentum cooling system sweeps the beam deposited by the RF away from the edge of the tail and decelerates it towards the dense portion of the stack, known as the core.
The opposite of the “error” signal is applied to the antiproton at the kicker.
www-bd.fnal.gov /public/antiproton.html   (971 words)

 Owen Chamberlain, 85, Dies; Discovered Antiproton - New York Times
The antiproton, discovered in 1955 by a team led by Dr. Chamberlain and another Berkeley physicist, Emilio Segrรจ, was the second bit of antimatter that physicists had created in what were then referred to as atom smashers.
The antiproton also became a workhorse of experimental particle physics, as scientists later spent decades smashing it into protons in racetrack-shaped accelerators and measuring the sprays of weird new particles that emerged, producing what seemed to be an endless stream of Nobel Prizes.
Steven Weinberg, a physics Nobelist at the University of Texas, said that while the existence of the antiproton had been predicted decades before the Berkeley experiments, the laboratory discovery of the particle was still highly anticipated.
www.nytimes.com /2006/03/02/science/02chamberlain.html?ex=1298955600&en=7851361dda75ca58&ei=5088&partner=rssnyt&emc=rss   (836 words)

 A. Gray's Web Page: Proton - AntiProton Collisions
Antiprotons are generated in the "Antiproton Source," a stationary target accelerator.
Antiprotons are collected from the collision, focused, and sent to the Antiproton Accumulator (storage) Ring.
The Main Injector is a synchrotron accelerator with a circumference of 3319.419 m [4] that replaced the Main Ring in 1998.
students.washington.edu /graya/HCollisions.html   (831 words)

 Science@Berkeley Lab:The Golden Anniversary of the Antiproton
The time to cull the antiproton from the surrounding herd would be brief: within about a 10 millionth of a second after it appears, an antiproton comes into contact with a proton and both particles are annihilated.
To measure velocity, which was used to separate antiprotons from negative pions, the Berkeley researchers deployed a combination of scintillation counters and a pair of Cerenkov detectors.
If a suspect particle was truly an antiproton, the Berkeley researchers expected to see the signature star image of an annihilation event, in which both the antiproton and a proton or neutron from an ordinary nucleus (presumably that of a silver or bromine atom in the photographic emulsion) died simultaneously.
www.lbl.gov /Science-Articles/Archive/sabl/2005/October/01-antiproton.html   (1800 words)

 Cancer Research Testing Antimatter ; Antiprotons Found To Be Effective - Science - RedOrbit
Michael Holzscheiter and a team of researchers found that beams of antiprotons -- a form of antimatter -- are four times more effective in destroying tumor cells than existing treatments using proton beams.
The proton beam releases energy near the end of its flight path, not along it, so when doctors calibrate the proton beams to end their journey at a tumor, cell- destroying energy hits the cancer, not healthy tissue.
That means antiproton therapy could have an even more significant impact on cancer survival rates, especially when tumors are in sensitive areas like the brain and near the spinal cord.
www.redorbit.com /news/science/720936/cancer_research_testing_antimatter__antiprotons_found_to_be_effective/index.html?source=r_science   (826 words)

The rate at which the circulating antiproton completes an orbit around the trap, known as the cyclotron frequency, is equal to the product of magnetic field strength and its electrical charge divided by its mass.
In separate measurements of a single proton in their trap, they confirmed that the cyclotron frequency of antiprotons and protons is identical to one part in a billion--a factor of 40 improvement over their previous measurements involving many trapped particles and 45,000 times more precise than earlier measurements with hot antiprotons.
As the antiproton dissipated this energy in the trap, the researchers observed an increase in cyclotron frequency, signalling a decrease in the mass.
www.aip.org /pnu/1995/split/pnu218-1.htm   (257 words)

 Macroparticle simulations of antiproton lifetime at 150 GeV in the te vatron
In this paper we report on a systematic study of antiproton lifetime at the injection energy of 150 GeV in the Tevatron.
Initial results show that the antiproton lifetime as a function of the proton intensity from the simulation is in good agreement with that from the experimental measurements.
The antiproton lifetime can be significantly improved by increasing the beam separation and by reducing the antiproton emittance.
repositories.cdlib.org /lbnl/LBNL-51808   (234 words)

 Antiprotons 4 times more effective than protons for cell irradiation
Started in 2003, ACE (Antiproton Cell Experiment) is the first investigation of the biological effects of antiprotons.
Further tests are planned to fully assess the effectiveness and suitability of antiprotons for cancer therapy, and to assure that less damage is caused to healthy tissues compared to other methods.
Antiproton 1984: Proceedings of the VII European Symposium on Antiproton Interactions held in Durham, 9-13 July 1984 (Institute of Physics conference series)
www.brightsurf.com /news/headlines/27234/Antiprotons_4_times_more_effective_than_protons_for_cell_irradiation.html   (1134 words)

 CERN Courier - ASACUSA measures antiproton - IOP Publishing - article
In the ASACUSA experiment, samples of antiprotonic helium - an atom with an antiproton and an electron orbiting a normal helium nucleus - were produced using CERN's Antiproton Decelerator facility, and irradiated with a tunable laser beam, the frequency of which could be measured very precisely with the Hall-Hänsch frequency-comb technique.
The laser beam could be tuned to one of several characteristic frequencies of the antiprotonic atoms, each frequency corresponding to an atomic transition of the antiproton.
Since these frequencies were determined by the properties of the antiproton, the ratio of the antiproton mass to the electron mass could then be calculated from the measured values.
www.cerncourier.com /main/article/46/6/6   (317 words)

 TRAP Collaboration
Antiprotons are slowed, cooled and eventually stored in thermal equilibrium at 4.2 K, an average energy more than ten billion (10,000,000,000) times lower than the energy of previously available antiprotons.
Torr, and nondestructive detection of the radio signal from a single trapped antiproton, made it possible to show that the charge-to-mass ratios of the antiproton and proton differ in magnitude by less than 9 parts in 100 billion (100,000,000,000).
All the initial cold antiproton experiments were carried out at the CERN Laboratory with antiprotons coming from its Low Energy Antiproton Ring (LEAR), a unique facility that then closed.
hussle.harvard.edu /~atrap/Background/Trap/TRAP.html   (347 words)

 Success at the Antiproton Decelerator (AD)
Physicists at the AD have succeeded in slowing antiprotons down from an initial momentum of 3.5 GeV/c to their target momentum of 100 MeV/c.
A range of particles and antiparticles are formed, and the antiprotons are separated off using magnets.
The role of the Antiproton Decelerator is to decelerate and cool the beam, down to 100 MeV/c.
bulletin.cern.ch /9948/art4/Text_E.html   (980 words)

 Owen Chamberlain Summary
The antiproton was hypothesized as being a mirror image of the proton, a particle found in the nucleus of atoms.
Proving the existence of the antiproton confirmed that idea of atomic symmetry; it was also an important breakthrough for particle physicists in their study of antimatter.
Finding the short-lived antiprotons amidst the collision debris generated by the atom smashing process was the next major hurdle to be overcome.
www.bookrags.com /Owen_Chamberlain   (1122 words)

 Antiprotons Map Nuclear Surface
An antiproton collides with a neutron at the surface of a nucleus.
The team used antiprotons from the Low-Energy Antiproton Ring (LEAR) at CERN, the European particle physics center in Geneva, to probe the surfaces of over 20 heavy nuclei with two different techniques.
The identity of the particle destroyed by the antiproton determined the type of radioactive isotope left behind.
focus.aps.org /story/v8/st11   (526 words)

 Physics Today - Search and Discovery
ATRAP is designed to confine both antiprotons and positrons in the same, relatively small, trap (with a radius of 1.2 cm).
The third experimental collaboration, ASACUSA, is continuing measurements begun at LEAR of the spectral lines of helium atoms in which an antiproton has replaced an orbital electron; the group hopes to determine accurately such properties of the antiproton as its mass and magnetic moment.
They have seen evidence that the antiprotons are being cooled by collisions with the positrons stored in the same trap.
www.physicstoday.org /pt/vol-53/iss-10/p22.html   (587 words)

 ANS : Publications : Journals : Fusion Science and Technology : Volume 36 : Antiproton Fast Ignition for Inertial ...
In the second, autocatalytic scheme, the antiprotons are preemplaced at the center of the capsule prior to compression.
antiprotons are required to initiate fast ignition in a typical ICF capsule and show that incorporation of a thin, heavy metal shell is desirable to enhance energy deposition within the ignitor zone.
However, in addition to the practical difficulties of storage and manipulation of antiprotons at low energy, the other large uncertainty for the practicality of such a speculative scheme is the ultimate efficiency of antiproton production in an external, optimized facility.
www.ans.org /pubs/journals/fst/va-36-2-219-233   (328 words)

 CERN Courier - Antiproton physics takes ano - IOP Publishing - article
The latest in the Low Energy Antiproton Physics series of conferences in Bonn showed that this field of research is increasingly vibrant and exciting, as Walter Oelert describes.
Though limited to low-energy antiproton research with only a pulsed extracted beam, the AD is regarded as the successor of LEAR after it closed down at the end of 1996, together with the Antiproton Accumulator (AA) and Antiproton Collector (AC).
Probing how antiprotons interact with matter at very low energies is still a topical field for precise studies of the electromagnetic and strong forces and their interplay.
cerncourier.com /main/article/45/7/32   (1465 words)

 Physics Today - Search and Discovery
ATRAP is designed to confine both antiprotons and positrons in the same, relatively small, trap (with a radius of 1.2 cm).
The third experimental collaboration, ASACUSA, is continuing measurements begun at LEAR of the spectral lines of helium atoms in which an antiproton has replaced an orbital electron; the group hopes to determine accurately such properties of the antiproton as its mass and magnetic moment.
They have seen evidence that the antiprotons are being cooled by collisions with the positrons stored in the same trap.
www.aip.org /pt/vol-53/iss-10/p22.html   (587 words)

 Fermilab - CDF - Plain English Summaries
Such collisions are thought to be caused by the exchange of a "pomeron" between the proton and antiproton.
In our two-dimensional pattern of such collisions, the particles from proton or antiproton dissociation will cover an angular region in the forward or backward proton direction, or in both these regions if both the proton and antiproton dissociate, while the rest of the event is empty of particles.
We actually selected events with a forward (leading) antiproton, which guarantees the presence of a rapidity gap associated with it.We then argued that the presence of this gap on the antiproton side is proof that no color-parton exchanges occurred in the event, which would have filled this gap.
www-cdf.fnal.gov /PES/sdd.html   (904 words)

for the use of antiprotons as the form of the antimatter is crucial tothe use of antimatter for propulsion.
In order to use antiprotons as a propulsion fuel, it will benecessary to find a more compact method of storage than an iontrap, which is limited to relatively low ion densities.
Then a decision could be made whetherto proceed with the construction of an antiproton factory thatcould produce the hundreds of milligrams a year needed to run aspace program.
www.transorbital.net /Library/D001_S01.html   (1441 words)

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