Slashdot Mirror
NC State Creates Most Powerful Positron Beam Ever
eldavojohn writes "A fairly large breakthrough took place earlier this month with the most powerful man-made antimatter electron beam ever being created at North Carolina State University. Professor Hawari who worked on the project explains its benefits: 'The idea here is that if we create this intense beam of antimatter electrons — the complete opposite of the electron, basically — we can then use them in investigating and understanding the new types of materials being used in many applications.'"
Whatever you do, don't cross the streams...
My
So, will it make my Ironman watch run backwards? OR block out all neural activity?
Professor Hawari who worked on the project explains its benefits: 'The idea here is that if we create this intense beam of antimatter electrons -- the complete opposite of the electron, basically -- we can then use them in investigating and understanding the new types of materials being used in many applications.'"
He added: " We are not quite sure how long it will take to miniaturize the technology for shark mounted applications, but we expect this to be investigated thoroughly in the future"
Currently, there are approximately 25 universities across the United States with active nuclear reactors on campus
You know, when you've read as many science fiction books as I have, this shit is a liiiitle creepy.
"No freeman shall ever be debarred the use of arms." -- Thomas Jefferson
In seemingly unrelated news, Duke University ceases to exist, somehow evaporated by a wave of unknown positron emission energy. But little seem to care, since Duke sucks anyways!
http://positrons.physics.lsa.umich.edu/nanopos/Publications/Reprints/Annual%20Rev%20Materials%20Research%20PAS%202006.pdf Used mostly for characterizing porus materials. Fun read if you find materials or nuclear science interesting, however perhaps too boring to put forth as informations in TFA.
Electron microscopes can already image at the atomic level, but a positron microscope has advantages because it can give complimentary information (e.g. about the positions of atomic vacancies). You can also use positron beams for PALS (Positron Annihilation Lifetime Spectroscopy), which is a powerful tool for determining the distribution of sizes in (nano-scale) voids in materials (difficult to measure by any other technique). It's also worth remembering that PET scans used in medicine involves a positron-emitting chemical injected into the patient.
There are probably a whole bunch of other experiments that positrons would be great for performing, but intense positron sources are not readily available. The development of more intense positron sources will certainly be welcomed by the scientific community, as it may allow previously unimagined types of measurements.
I've seen Scotty create beams of antimatter with two phasers and a tricorder, big whoop.
So basically, -1 troll/offtopic is really slashdots way of saying "I hate that you thought of something before me."
So if you shot a powerful positron beam at something and also shot a powerful electron beam at it also, would you have a continuous antimatter explosion at the crossover point?
Kinda. It's more like a gamma-ray (and neutrino) light source. The electron-positron annihilation releases a tad over a MeV mainly as two photons that fly off in opposite directions - plus a neutrino, so the photons are somewhat under half the energy each.
Think of it as an x-ray tube - without the vacuum tube - but with the power supply, instead of being in the kilovolt range, cranked up to whatever the beam voltage is plus an extra half-million volts or so.
Also, if you have a target you don't really need the electron beam. Just ground it well enough that it doesn't accumulate enough positive voltage to deflect the positron beam to somewhere else.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
I won't be impressed until scientists are able to create an inverted tachyon pulse that solves any problems caused by spatial anomalies.
You want to know who isn't running Firefox 2.x? They spell it "definately" and "rediculous".
...We'll cross the streams. No, don't. The pee goes everywhere.Kwisatz Haderach
Sell the spice to CHOAM
This Mahdi took Shaddam's Throne
I took a class that involved going to the University of Texas' learning reactor. To get in the front door, one had to get buzzed in by someone behind a desk. To get to the controls or the reactor, one had to get past several security measures and some very solid metal doors. The first time the prof took us back there, he warned us that the door could only be open for 3 minutes. I asked him what happened if that time was exceeded, and he said that a SWAT team would be there within five.
The Stanford Linear Accelerator Center, or SLAC, generates and accelerates electron and positron beams (and when needed, polarized or spin oriented beams) for colliding beam and fixed target experiments. SLAC has literally hundreds of dipole, quadrapole, and sextupole electromagnets placed along their accelerator, beam lines, and storage rings, all for focusing and directing their charged particle beams. If the center of mass of colliding electron and positron beams is high enough (at a collision energy called a "resonance") new particles will be created from the combined beam energies. During the 1990's, SLAC accelerated electrons and positrons to approximately 49 Giga Electron Volts (or GeV) each with their accelerator. After the two beams drifted in evacuated beam lines away from the accelerator, they were directed such that the electron beam and the positron beam approached an interaction point in the center of a large particle detector called SLD, from opposite sides. In the detector, the two beams would collide, creating new chargeless particles called Z-Zero or Z-Naught particles, with a collision energy of about 95.5 GeV. The Z-Zero, before it decays, is about one half as heavy as a silver atom, but quickly decays into a lot of smaller fragments, some charged and others not charged. The mass of that Z-Zero particle represents the direct conversion of the accelerator's energy into matter.
http://www2.slac.stanford.edu/vvc/detectors/sld.html
In the diagram shown in the link above, look for the e- and e+ labels. Those represent the electron (e-) and positron (e+) beams entering the SLD detector from opposite sides. In the center of the SLD detector is a small cylindrical piece called a Vertex Detector. The center of the vertex detector (a silicon CCD device about the size of a soft drink can with several million pixels in three concentric layers) is where SLAC's electrons actually collided with positrons. The parts of the detector around the Vertex detector are like the layers of an onion. Each layer gathers a different kind of data about the collisions that took place inside the vertex detector at the interaction point. There are a lot of very sophisticated electronics in the layers of all particle detectors, but all of the electronics have one purpose, to gather information about the decay fragments coming from the electron/positron collisions so the events that took place during and immediately after the collision can be reconstructed and analyzed with very sophisticated computers.
Beginning in 1998, SLAC began an experiment called the asymmetric B-meson factory, or "B Factory" for short. In the B Factory, the electron beams run at a little over 9 GeV beam energy, while the positron beams run at only about 3 GeV. Both colliding beams run at very high currents, on the order of two amperes in the electron storage ring, and three amperes in the positron storage ring. The collision of these two high current beams produces millions of B mesons, each with a residual momentum (due to the asymmetric beam energies) that makes it possible for the particle physicists to study more effectively how those B mesons decayed.
Here is a link to more information about "Storage Rings" and their electromagnets:
http://en.wikipedia.org/wiki/Storage_ring
And here are links to three of SLAC's web pages, where you can learn more about colliding beam physics. BaBar is name of the particle detector used to study their decaying B Mesons, and PEP-II is the storage ring collider used to make those B Mesons.
The PEP-II storage ring collider is at: http://www.slac.stanford.edu/grp/ad/ADPEPII/ADPEPII.html
The BaBar detector is at: http://www-public.slac.stanford.edu/babar/
And SLAC's main web page (the first web page in t
An analog gray hair frantically clinging to the trailing edge of technology.
Thank you for your kind remarks.
I used to work at SLAC, and I got to know something about how the whole machine worked and what we (as a member of the team who made it work) were doing. You are 100% correct about beer and bubble chambers. At one time SLAC had a huge bubble chamber filled with liquid hydrogen (as I recall, I could be wrong). They also had a huge cloud chamber, and even a very large spark chamber, and giant solenoid magnets around those chambers, to make charged particles leave curved tracks. Back then, they photographed each pulse of the accelerator as seen in the bubble chamber, the cloud chamber, or the spark chamber (something like 5 to 10 pulses per second) on black and white movie film. They then had teams of people studying those films, frame by frame, looking for "interesting events". I'm sure the folks doing this visual analysis rapidly developed eye strain. I'm also sure the development of the particle detector (as represented by SLD) was a great improvement, both because the experimental machinery could run faster, and because computers could do the data analysis much faster and more accurately than people.
Although I am no longer working for SLAC, I always thought SLAC was a great place to work. There was so much history there that I could see and touch, and I sometimes got to talk with the people who were there when exciting discoveries were made. SLAC was where quarks were first observed in the form of three small (but hard) pits in the middle of a large squishy thing called a proton. They made this discovery by studying the scattering of some high speed electrons shot into a tank of liquid hydrogen. They then shot the same high speed electron beam into a tank of liquid deuterium. Deuterium has one proton and one neutron in its nucleus. To derive what the neutron looked like, they subtracted out what the scattering effect was from liquid hydrogen (which has only a proton in it's nucleus) and from that concluded that neutrons also were large squishy things with three hard pits in the middle, just like protons.
SLAC and the team that performed this high speed electron scattering experiment won a Nobel Prize for their work.
SLAC is also where the quark theory was tested in one of the first storage rings called SPEAR, earning SLAC another Nobel Prize. The Tau particle was found there, too, although the tau had been recorded but not recognized in other places. The discovery of the tau earned SLAC their third Nobel Prize.
While I worked there, my email and newsgroup signature line was, "Nobel Prizes R Us!"
An analog gray hair frantically clinging to the trailing edge of technology.