A New Dot on the Livingston Curve
Nov. 30th, 2009 05:51 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
beamjockeyI learned today that CERN's Large Hadron Collider has broken the energy record for particle beams, circulating a beam of protons with 1.18 trillion electron volts (TeV) energy. The previous record, 0.98 TeV, was held by Fermilab's Tevatron collider.
Both countercirculating beams of protons were accelerated to 1.18 TeV. By next year the LHC folks hope to begin taking physics data at a beam energy of 3.5 TeV. With improvements, the machine is designed to reach a beam energy of 7 TeV, which means 14 TeV available in head-on collisions.
Today is a good time to think about the Livingston Curve.
Long before Gordon Moore observed that the number of transistors per integrated circuit was doubling every 24 months, M. Stanley Livingston pointed an example of exponential growth in technology. Livingston, the physicist who had built the first cyclotron in the early 1930s, plotted the beam energy of each new particle accelerator against the year when it had first operated. "When energy is plotted on a logarithmic scale, the envelope of the points is remarkably close to a straight line, indicating an increase in energy by a factor of 10 every six years."
Livingston's own plot, from his 1962 book with J.P. Blewett, Particle Accelerators, expressed as beam energy in the "laboratory frame:"
Modern Livingston plot expressed in center-of-mass energy for accelerated particles:
(Click to see Kurt Riesselmann's writeup for Symmetry)
It's interesting that, though each accelerator technology has practical limits-- it becomes very difficult to build cyclotrons of ever-higher energies, for example-- new methods of acceleration have been developed which managed to push the energy frontier higher anyway. Betatrons, synchrotrons, and storage rings followed. In the same manner, Moore's Law is propelled by constant innovations in methods and materials for making chips.
Peak beam energy is not the only meaningful parameter in physics, of course. And older acceleration methods are not necessarily abandoned. Cyclotrons and linacs are still being built to provide beams of a few million electron volts for a variety of purposes. But there is always excitement at the energy frontier.
The Large Hadron Collider's dot will soon be much higher than 1.18 TeV. Still, it's good to see them stake their claim in new blank territory at the top of the Curve. I'm sure M. Stanley Livingston would have been proud of CERN.
Both countercirculating beams of protons were accelerated to 1.18 TeV. By next year the LHC folks hope to begin taking physics data at a beam energy of 3.5 TeV. With improvements, the machine is designed to reach a beam energy of 7 TeV, which means 14 TeV available in head-on collisions.
Today is a good time to think about the Livingston Curve.
Long before Gordon Moore observed that the number of transistors per integrated circuit was doubling every 24 months, M. Stanley Livingston pointed an example of exponential growth in technology. Livingston, the physicist who had built the first cyclotron in the early 1930s, plotted the beam energy of each new particle accelerator against the year when it had first operated. "When energy is plotted on a logarithmic scale, the envelope of the points is remarkably close to a straight line, indicating an increase in energy by a factor of 10 every six years."
(Click to see Kurt Riesselmann's writeup for Symmetry)
It's interesting that, though each accelerator technology has practical limits-- it becomes very difficult to build cyclotrons of ever-higher energies, for example-- new methods of acceleration have been developed which managed to push the energy frontier higher anyway. Betatrons, synchrotrons, and storage rings followed. In the same manner, Moore's Law is propelled by constant innovations in methods and materials for making chips.
Peak beam energy is not the only meaningful parameter in physics, of course. And older acceleration methods are not necessarily abandoned. Cyclotrons and linacs are still being built to provide beams of a few million electron volts for a variety of purposes. But there is always excitement at the energy frontier.
The Large Hadron Collider's dot will soon be much higher than 1.18 TeV. Still, it's good to see them stake their claim in new blank territory at the top of the Curve. I'm sure M. Stanley Livingston would have been proud of CERN.
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Date: 2009-12-01 08:56 pm (UTC)Is this some sort of complicated relativistic correction to do with the difference between colliding two beams and colliding a beam and a target? Is it a figure for LHC colliding beams of uranium atoms and getting a 92^2 factor from somewhere?
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Date: 2009-12-01 10:02 pm (UTC)I enjoyed it when I ran across it, but apparently it also irritated a number of people (including some of my friends).
Aha: 1989 Apr, pg 112
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Date: 2009-12-08 05:36 am (UTC)LHC is a neat machine, and I'm really glad someone somewhere is still pushing the envelope in high energy physics, but it still galls me to remember that the original design for SSC's high energy booster could have done 4 TeV proton on proton collisions. Just the booster.
20 TeV on 20 Tev in the main rings would have been glorious. Had we only had the will to continue.