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In 1993, the U.S. Congress canceled the Superconducting Super-Collider
Project (SSC), the Department of Energy’s $8 billion high-energy proton-proton
collider synchrotron that was then under construction in Waxahachie,
Texas. About $2 billion had been spent,
the ring tunnel was 2/5 complete, the first prototype superconducting magnets
had shown excellent performance, and the project was moving forward at a rapid
pace, when Congress shot it down. The
SSC was to have been the next great leap forward for particle physics in the
United States, the project that was to take us into the 21st century
with leadership in this forefront area of physics. Instead, the plug was pulled, producing a disaster for all of
particle physics. A fictionalized
account of the events leading up to the project’s cancellation can be found in
my hard SF novel Einstein’s Bridge.
In the aftermath of the SSC cancellation, the rival European project, the CERN
Laboratory’s Large Hadronic Collider (LHC) was delayed
after the SSC’s competitive pressure had been removed, and its target date of
first operation was pushed back from 2000 to about 2008. Many particle physicists-refugees from the
SSC collapse managed to reach some accommodation with CERN and have joined the
LHC construction effort or one of the three LHC detector groups (ATLAS, CMS,
and ALICE). Many others, particularly
the younger SSC physicists, have had to abandon their careers in physics
altogether and now work as bankers, software developers, Wall-Street brokers,
etc. Some attribute the recent
instability of the stock market to the influx of former-SSC physicists with new
schemes for market manipulation.
Accelerator physicists in this country, that sub-group of physicists who specialize in the
design and construction of large accelerators, have suffered the devastating
impact of two successive cancellations of major high-energy physics collider
facilities by the U.S. Government, ISABELLE in 1985 and the SSC in 1993. Nevertheless, they are pushing forward again
with the design for a new multi-billion dollar collider facility, which they
call the Next Linear Collider (NLC). In this effort they are in direct
competition with a design group at the DESY laboratory in Hamburg Germany that
is proposing the Tera Electron Volt Energy Superconducting
Linear Accelerator (TESLA) facility, and a design group at the
KEK laboratory in Japan that is promoting the Japan Linear Collider
(JLC). All of the proposed machines are
“linear”, using a long straight line of accelerating structures as opposed to
the circular magnet-ring design of the SSC and LHC. This is because high-energy electrons lose energy rapidly due to
synchrotron radiation when bent in a curved path, with the energy loss rising
as the 4th power of the particle energy. Above some critical energy on the order of 100 GeV, electrons and
positrons must be accelerated in a straight line.
At the recent high-energy physics gathering at Snowmass, Colorado, with the theme
“The Future of Particle Physics”, there were detailed presentations from all
three of these rival projects. The
projects are very similar in many ways. All would collide electrons and positrons at an energy of 0.5 to 1 TeV
(1012 electron volts) in the center of mass of the collision, with a
luminosity (rate of collisions in a given area) of about 1034
collisions per cm2 per second. Each facility would be constructed in a tunnel about 30 km (19 miles)
long containing two linear accelerators, each 15 km long, aimed at a collision
point and detector complex at its center. Each would accelerate the electrons and positrons in several tens of
thousands of superconducting cavity resonators that develop average accelerating
electric fields of about 50 million volts per meter of cavity length. Each would require 6 to 8 years to
construct, once funding was secured. And each would have a large cost. At this stage the cost is not well specified, but informed guesses range
between 2 and 6 billion dollars, (or roughly this year’s cost overrun for
NASA’s International Space Station Project).
In the present design studies, the two non-US facilities would be located in
places that would exploit existing accelerator complexes in Japan and
Germany. In one JLC design study, the
collider would be centered at the KEK laboratory near Tokyo, with the linac
arms extending away in oppositely-directed tunneled under suburban
neighborhoods. Another JLC study,
however, envisions using highway construction techniques to blast the accelerator
tunnel from the stone under a mountain range near Tokyo, saving about a factor
of 10 in tunnel construction costs but requiring more equipment construction
because the existing KEK infrastructure could not be used. The JLC facility would also use the
high-energy electron beams of the facility to create an x-ray laser. The free-electron laser formed by the
ultra-low emittance electron beam would produce both incoherent and coherent
beams of hard x-rays for applications in condensed matter physics and in
molecular biology.
The design study for the TESLA facility would use the DESY laboratory in Hamburg as
one injection station of the facility, with the village of Westerhorn 30 km
away as the other injection station. The collision point and detector complex would be located at the village
of Ellerhoop half way between Hamburg and Westerhorn. The tunnel would be bored under urban and suburban neighborhoods
and farmland in the vicinity of Hamburg. The Germans anticipate no not-in-my-back-yard (NIMBY) problems
with local residents in doing this, because the DESY facility has been
constructed in the same way, in tunnels deep under the city of Hamburg.
No site in the United States has been specified for the NLC design study done
here. However, if the project goes
forward one can envision extensive site-selection hearings and site proposals
similar to those that preceded the selection of the SSC site. The site-selection process for the SSC was
very interesting to watch, because it brought the united interests of basic
science, pork-barrel politics, and regional boosterism into direct conflict
with the NIMBY concerns of the nearby residents and with the sizable fraction
of the population that has a deep-seated superstitious fear of anything
nuclear. The culmination of the site
selection process, with the selection of Waxahachie, Texas, ultimately based on
the geology of the Austin Chalk beneath the site, was controversial, with many
of the losers accusing the powerful Texas Congressional delegation of stacking
the deck. If the NLC ultimately goes
forward, the site selection should be a three-ring circus.
In about 2008 the new CERN LHC will bring pairs of protons into head-on collision
at 7 TeV. That collision energy is
about seven times greater than the energy of the three proposed linear
colliders that were showcased at Snowmass. Therefore, it’s fair to ask why we would need these machines at all if
they run at lower energies than the LHC. The answer is in the details.
Protons are composite particles made of three quarks pasted together with gluons. The proton has a mass of about 936 MeV, but
the quarks that form it have masses of only about 10 MeV each. The remainder of the proton’s mass is
contained in the gluons and in the “Fermi motion” of the quarks, the kinetic
energy of the quarks as they rattle around in their little box. The result of this is that when the quarks
in two protons collide, they carry into the collision only a small fraction of
the proton’s total energy. Moreover,
their collision energy is somewhat indefinite, because it is smeared by the
quark Fermi motion. Thus, a proton
collider is a shotgun, propelling multiple pellets at each other, each with a
somewhat indefinite energy.
On the other hand, the proposed electron-positron colliders are more like a
high-precision rifle. The electron and
positron in collision are “pointlike” particles. They therefore bring all of their energy to each central
collision. For this reason, a 1 TeV
electron-positron collider is roughly equivalent to t 10 TeV proton-proton
collider. Moreover, the
electron-positron collision energy is not smeared by Fermi motion. Therefore, a 1 TeV electron-positron collider
has particle production capabilities that compare very favorably with those of
the LHC collider, and it offers many advantages in experiments where precise
collision energy is important.
The problem facing contemporary particle physics is that the Standard Model, the current theory of fundamental particles and their interactions, works too well. It is in good agreement with the complete body of data collected by particle physics experiments during the past decades. However, it is not a theory that provides any deep understanding of the inner workings of the universe. It is a paste-up theory that depends on about two dozen arbitrary "constants": particle masses, force strengths, and interconnection strengths. We have no idea where these constants come from or how they are related to each other. We are sure that there must be a better, more fundamental theory behind the Standard façade, but we cannot discover it without data at higher energies. We need an accelerator with enough energy to make the Standard Model "break". We must find places where its predictions fail, so that we can learn what lies beyond. It is not clear that the LHC, with its 7 TeV proton collision energy will be able to do this job. The proposed electron-positron collider is a complementary machine, a rifle that complements the LHC shotgun approach.
One dark cloud on the e-e+ collider horizon appeared
during a panel on new facilities at the Snowmass Meeting. Michael Holland of the Bush Administration’s
Office of Management and Budget stated that in order to make the case for the
new machine, be it the NLC or U. S. participation in the other projects, the
particle physics community would have to demonstrate that the new facility was
important not only to their own area of research, but also important to
“science as a whole”. Since no one can
speak for science as a whole (except perhaps this column), this requirement
would be almost impossible to satisfy.
Another panelist, Luciano Maiani, Director-General of CERN, declared that he found such
a stringent criterion for federal support “unfriendly to science” and an
inhibition to progress in basic research. Several members of the audience asked why NASA’s Space Station and
various defense-related projects were not being held to the same standard.
One key point on which the SSC Project foundered was the lack of international participation. The Europeans were pushing their own smaller
project, the LHC, and President Bush (the Elder) failed to directly ask
Japanese Prime Minister Miyazawa for
Japanese participation in the SSC construction during his famous up-chuck visit
to Japan in January, 1992. This time
around, if there is to be a 1 TeV electron positron collider somewhere in the
world it must be an international collaboration, with the strong
American, European, and Japanese groups all working as a team to construct it
and extract the physics lessons it will provide. Deciding where it will be built will be a major problem for all
of the competitors. Persuading the
chauvinistic and mercurial U. S. Congress and the Bush Administration, which
has so far been accumulating an anti-science record, to become a major
contributor to the project will be a major problem for the particle physicists
of this country, particularly if the machine is constructed elsewhere.
Since no one else has yet had the temerity to venture into these waters, let me make
a modest proposal. I suggest building
the new electron positron collider in the Australian Outback. Then, like most U. S. National Laboratories,
it would be located in a remote and forbidding place, roughly equidistant from
all of its designers and users, and constructed on inexpensive neutral ground
where none of its promoters will have an advantage and everybody will be
equally uncomfortable.
John G. Cramer's 2016 nonfiction book (Amazon gives it 5 stars) describing his transactional interpretation of quantum mechanics, The Quantum Handshake - Entanglement, Nonlocality, and Transactions, (Springer, January-2016) is available online as a hardcover or eBook at: http://www.springer.com/gp/book/9783319246406 or https://www.amazon.com/dp/3319246402.
SF Novels by John Cramer: Printed editions of John's hard SF novels Twistor and Einstein's Bridge are available from Amazon at https://www.amazon.com/Twistor-John-Cramer/dp/048680450X and https://www.amazon.com/EINSTEINS-BRIDGE-H-John-Cramer/dp/0380975106. His new novel, Fermi's Question may be coming soon.
Alternate View Columns Online: Electronic reprints of 212 or more "The Alternate View" columns by John G. Cramer published in Analog between 1984 and the present are currently available online at: http://www.npl.washington.edu/av .
References:
Background on the cancellation of the SSC
Project:
Einstein’s Bridge, John Cramer, Avon (1997),
ISBN 0-380-78841-4; http://bookviewcafe.com/bookstore/?s=Cramer
.
See also the URL: http://faculty.washington.edu/jcramer/EBridge/EOS.html
The Japanes JLC Project:
See the URL: http://www-jlc.kek.jp
The US NLC Project:
See the URL: http://www-project.slac.stanford.edu/lc/nlc.html
The German TESLA Project:
See the URL: http://tesla.desy.de
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website.