RE: [asa] LHC, TOE, and the limits of knowledge

From: Dehler, Bernie <>
Date: Tue Sep 16 2008 - 17:07:06 EDT

"I don't see how we can ever get anything in the neighborhood of the LHC energy on a tabletop."

That's because you are using current understanding with current knowledge. You don't yet know of the new inventions, new knowledge, and new technology. It is like the people with Eniac not knowing about transistors and binary computing as we do today to accomplish what we do today.

"Where a computer like the ENIAC is equipped with 18,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and weigh only 1 1/2 tons."
Popular Mechanics, March 1949

From: [] On Behalf Of Kirk Bertsche
Sent: Tuesday, September 16, 2008 1:14 PM
Cc: ASA Affiliation; Randy Isaac
Subject: Re: [asa] LHC, TOE, and the limits of knowledge

interestingly, there IS an exponential "law" in accelerator physics called the Livingston Curve. But unlike Moore's law, it only plots the equivalent collision energy on a fixed target, not the physical size of the devices. And it looks like the Livingston curve may be starting to plateau with the LHC (

In order to accelerate particles to a high energy in a small physical size, one of two things is needed:
1) a recirculating ("circular") acceleration scheme with extremely strong bend magnets
2) a linear acceleration with an extremely high accelerating gradient

Bend magnet strength is limited by fundamental physics. (Superconductors lose their superconductivity if the field is too high. Normal electromagnets would require prohibitively high power. Permanent magnets would require a very tiny beam aperture for higher fields.) I don't see much room to reduce the size of circular machines; maybe a factor of 2 or so with lots of good ideas and hard work.

Linear acceleration may be a bit more promising. Some interesting high-gradient linear acceleration schemes are being investigated, such as using the electric fields in an intense laser pulse to accelerate electrons. ( But even with all of this, getting to higher energies than the LHC would require a very long accelerator.

I agree with Don's and Randy's pessimism; I don't see how we can ever get anything in the neighborhood of the LHC energy on a tabletop.

Kirk Bertsche
(accelerator physicist)

On Sep 16, 2008, at 11:02 AM, Randy Isaac wrote:

Those of us who have grown up with the electronics industry have practically come to believe that the scaling law is a universal entitlement; we merely wait for the right invention. In fact, the transistor and the magnetic storage cell are two rather unique examples with surprisingly few additional examples. Does anyone know of another? Will there be unforeseen inventions which will trigger new ways of doing things. Absolutely. Can we predict what they will be? No. But we can have some guesses. Getting a tabletop TEV accelerator is not one where I would recommend putting all your life's savings. Maybe not even a dime of it. At least until Burgy has his rocket that will take us to Betelgeuse and back in one lifetime.



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Received on Tue Sep 16 17:08:11 2008

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