AOH :: TEVATRON.TXT|
The Tevatron particle collider
Title-> The Tevatron. (the world's first superconducting
synchrotron at the Fermi National Accelerator Laboratory)
Authors-> Lederman, Leon M.
On July 3, 1983, my colleagues and I at Fermi National Accelerator
Laboratory (Fermilab) near Chicago started the countdown for the
inaugural run of the world's first superconducting synchrotron, the
Tevatron. It would send a trillion protons on a speed-of-light
journey, ending in a collision unlike any that has occurred since very
shortly after the birth of the universe. The Tevatron would also
launch physicists on an unrivaled adventure in understanding the
nature of matter and the discipline of building and operating colossal
To begin the test, we activated the Main Ring, Fermilab's older
synchrotron, to energize the positively charged protons to a mere 120
billion electron volts (GeV). In a nerve-racking instant the protons
were injected into the Tevatron, where more than 1,000 superconducting
magnets literally took charge. The magnets efficiently produced a
powerful field to guide the protons around a 6.3-kilometer circular
path no more than a few millimeters wide. In the control room,
technicians supervised the computer program that ramped the magnets up
in precise synchrony with the increasing energy of the protons: 200,
300, 400 GeV... When the magnetic field reached test-level strength,
the protons were smashed into a target at a world record 512 GeV.
The feat capped a 10-year effort to master the technology of
superconducting magnets in accelerators, and it marked the beginning
of an era in the physics of matter, energy, space and time. The new
"atom smasher" was heralded in newspaper across the U.S. and was
praised in messages that poured in from many institutions, including,
in particular, the U.S. Department of Energy (DOE), which had
allocated the funding.
During the past eight years, Fermilab has taken many steps to ensure
that the Tevatron will remain a preeminent facility for particle
physics. Fermilab has improved the superconducting magnet system,
developed an antiproton source and constructed a particle detector.
The Tevatron can now collide 900-GeV protons with 900-GeV antiprotons
to generate an unmatched 1.8 trillion electron volts (TeV).
With each burst of energy, the Tevatron creates a host of exotic
particles, producing data of unprecedented quality. The Tevatron has
confirmed many predictions of the Standard Model, the central theory
of elementary particles. It has also allowed investigators to explore
a domain where "no human eyeball has ever set foot," according to a
student with a penchant for mixing metaphors.
The Standard Model proposes that matter is composed of six kinds of
quarks and six leptons, and so far all these particles have appeared
in experiments except for the sixth quark, known as top. As the
Tevatron evolves during the next five years, it will generate, by most
physicists' reckoning, enough collisions to produce the top quark. If
it does not emerge, the Standard Model will face a major crisis.
The elusiveness of the top quark is connected to the most seminal
issues confronting particle physics. Why do all quarks and leptons
have different masses? Does an undiscovered force of nature bestow
mass on a particle? Are quarks and leptons composed of even smaller
particles? What do the interactions between quarks and leptons
suggest about the high-energy environment of the early universe?
Theorists have devised many explanations, which have exotic names such
as supersymmetry, technicolor, constituent models and superstrings.
The Tevatron seeks to illuminate the speculative jungle.
The Tevatron program began more than 15 years ago in anticipation of
the needs of the particle physicist today. During the 1970s,
elementary particle physics progressed as two kinds of accelerators
propelled particles to ever higher energies. Synchrotons at Fermilab
and the European laboratory for particle physics (CERN) near Geneva
smashed protons into fixed targets, and accelerators at Stanford
University, Cornell University and the Deutsches Elektronen-Synchroton
(DESY) in Hamburg collided electrons with their antimatter twins,
Although the proton synchrotons could accelerate particles to much
higher energies than the electron-positron colliders, they were in the
final analysis no more powerful than the colliders. When a protron
boosted to, say, 1,000 GeV is smashed into a target, most of its
energy is expended to accelerate the particles produced in the
collisions. Only 42 GeV is available to produce new particles. Here
the colliders have an advantage. When particles collide head-on,
their combined energy is available for creating particles or exploring
a new energy regime. Hence, a 1,000-GeV proton that smashes head-on
with a 1,000-GeV antiproton releases 2,000 GeV.
The power of an accelerator is not measured by its energy alone,
however. An accelerator must generate enough high-energy collisions
to produce statistically significant results. Collision rates are
generally lower for colliders than for fixed-target machines because
particles in a diffuse beam are much more likely to collide with a
dense, fixed target than with particles from another diffuse beam.
Overall, the colliders sacrifice a high collision rate for greater
During the 1970s, the two proton synchrotrons--the Super Proton
Synchrotron at CERN and the Main Ring at Fermilab--were competing
fiercely. Both laboratories were pushed to improve their machines to
study the Standard model and the fundamental interactions of
nature--the weak, electromagnetic and strong forces.
In 1977 CERN went all out to convert its machine from a proton
synchrotron to a proton-antiproton collider because it sought to
confirm or refute the existence of the so-called intermediate vector
bosons (the W[+], W[-] and Z). These massive particles are
responsible for the weak force. From 1977 to 1981 CERN developed a
device that collected and stored antiprotons. The device then
squeezed the antiprotons into small bunches using a technique called
stochastic cooling. The antiprotons were then injected into the CERN
Super Proton Synchrotoron, where they eventually smashed head-on into
In 1983 and 1984 CERN discovered the W and Z particles. For this
accomplishment, Carlo Rubbia, the leader of one of the experimental
groups, and Simon van der Meer, the inventor of stochastic cooling,
won the 1984 Nobel Price [see "The Search for Intermediate Vector
Bosons," by David B. Cline, Carlo Rubbia and Simon van der Meer;
SCIENTIFIC AMERICAN, March 1982].
Fermilab chose a different route to advance the field of high-energy
physics. The increasing power of the Super Proton Synchrotron was a
major concern to Robert R. Wilson, Fermilab's visionary first
director. He realized that if Fermilab develop a superconducting
magnet system, it could ultimately build an accelerator more powerful
than CERN's. The proposed Fermilab machine could boost charged
particles to higher energies because superconducting magnets can
produce a much stronger field than can conventional systems. In 1973,
therefore, Wilson started a program for a new superconducting magnets
for a new accelerator. Later Alvin V. Tollestrup, who came to
Fermilab in 1975 from the California Institute of Technology, became
the intellectual leader in developing these magnets.
As director-designate of Fermilab in the fall of 1978, I reviewed
various proposals to build an accelerator that would use
superconducting magnets. We concluded that such magnets not only
could sustain a more powerful accelerator but could also reduce
consumption of electricity. (From 1972 to 1978 Fermilab had nearly
doubled its power consumption, while its electricity costs increased
sixfold.). Because superconducting components do not resist the flow
of electricity at all, a superconducting magnet system would consume
considerably less power than a conventional one would. How best to
use the new technology was not at all clear. I therefore consulted
with an outside group of accelerator geniuses dubbed the three wise
men: Boyce D. McDaniel of Cornell University, Burton Richter of
Stanford University and Matthew Sands of the University of California
at Santa Cruz.
On November 11, 1978 I held a staff meeting to discuss the long-range
plans of the laboratory. It was Armistice Day, an appropriate time to
call a truce among several groups who had opposing ideas about how to
use the superconductor technology. After 18 continuous hours of
passionate debate, a clear consensus emerged--at least it seemed clear
to me and my advisers. We came up with two major initiatives. First,
we would build an accelerator based on a superconducting magnet system
and install it in the 6.3-kilometer tunnel occupied by the Main Ring.
This machine would smash protons into fixed targets as before but at
an energy level more than two times higher. Second, like CERN, we
would construct an intense source of antiprotons, inject them into the
accelerator and collide them with protons. The goal was to accelerate
protons and antiprotons to 1 teV and produce about 50,000 collisions
per second at a total energy of 2 TeV.
From 1979 to 1987 the program was implemented as envisioned in the
1978 plan, at a cost of about $250 million. The DOE supervised and
funded the program, but not without Sturm and Drang. The saving grace
was Andrew E. Mravca, a DOE official who believed in the program and
knew how to negotiate skillfully with a bureaucracy.
The story of the Tevatron is a very human one, dominated by a
collection of heroic figures. Physicists, professional engineers and
a corps of gifted amateurs devoted themselves to making the Tevatron
the world's most powerful accelerator. If a single factor accounts
for the success of this enterprise, it was the happy justaposition of
physicists and engineers.
When Fermilab set out to design the Tevatron in 1979, we knew it would
be significantly more complex than any previous accelerator. The
Tevatron would require a huge cryogenic system to cool the magnets
below the temperature at which they become superconductors
would need an intricate vacuum system to provide both thermal
insulation and a clear space in which to accelrate particles. It
would demand an elaborate safety network to protect the apparatus and
workers from the energy stored in the particle beams and the magnet
system. It would involve high-speed computers to monitor and control
such parameters as the temperature, pressure, field strength,
radiation level and beam positiom. Finally, the Tevatron would entail
sophisticated particle detectors to measure the energies and
trajectories of particles formed in collisions between protons and
antiprotons. Each of these systems took years to design and build.
J. Richie Orr wasin charge of the Tevatron project. Helen T. Edwards
became Orr's deputy and technical manager. Machine guru Thomas L.
Collins was principal designer of the accelerator system. Tollestrup
and Wilson, with help from Richard A. Lundy, were responsible for the
assembly line to produceM test and modify magnets.
The superconducting accelerator magnets posed major technical
challenges. The magnets must confine particles within a
one-centimeter region in the center of the vacuum tube as they steer
the particles around a 6.3-kilometer orbit, 50,000 times a second.
The accelerator amgnets generate a field as electric currents flow
through superconducting wires. The quality of the field depends on
the prescision with which the superconducting wires are placed around
the vacuum tube.
To guide particles, the magnets have to generate a nearly perfect
dipole field--one described by a north pole above the orbit and a
south pole below. beacuse it is practically impossible to do so, such
magnets as quadrupoles and octopoles were needed to correct for errors
in the dipole field.
Accomplishing this task presents several formidable engineering
problems. Huge forces push on the wires when they carry the electric
currents that create the required magnetic field. The stainless steel
clamps that hold the wires must withstand tons of force without
yielding more than a thousandth of a centimeter over the 6.4-meter
length of each dipole magnet.
PErhaps the most obstinate problem occurs during the acceleration of
particles, when the currents change rapidly and increase to 4,000
amperes in about 30 seconds. Changing fields tend to shake and twist
wires, creating friction and heat, which are anathema to the
superconducting state. The solution these problems evolved over a
decade of researh in laboratories around the world, but Fermilab's
physicists and engineers were the first to achieve success in the
period from 1973 to 1979.
Fabrication of the superconducting wire was still an exotic technology
in 1979. The alloy of niobium and titanium, after elaborate
metallurgical treatment, was packed into hollow copper tubes. A set
of 2,000 rods was then bundled together in a copper shell 250
millimeters wide. The assembly was heated in an oven, extruded
through a press and drawn through dies to make strands 0.6 millimeter
in diameter and 50 kilometers long. The niobium-titanium rods became
fine filaments 10 microns in diameter separated from one another by a
sheath of copper, which acts as an insulator at superconducting
temperatures (below five kelvins). When 23 strands are woven together
to form a cable, they can carry 5,000 amperes at superconducting
A mass-production assembly line for the superconducting magnets was
supervised by Lundy. His group built about 100 small models and
several hundred prototypes before they could get the magnets to
perform satisfactorily. They then fabricated about 900 dipoles, 250
quadrupoles and hundreds of other types of magnets used to correct
imperfections in the fields of the dipoles and quadrupoles. The total
included a reasonable number of spares to replace magnets that might
fail in operation.
In 1980 Fermilab built a large facility to test each magnet for
mechanical, cryogenic and magnetic properties. The vital statistics
of each magnet were logged into a computer program that later served
to advise where in the ring the magnet should be placed to cancel
residual field errors.
To provide enough coolant for all the superconducting magnets,
physicist William B. Fowler and engineer Claus H. Rode directed the
construction of the cryogenic system. A major component was a
liquid-helium plant that for a time was the world's largest. The
facility can now produce simultaneously 4,500 liters of liquid helium
per hour and a comparable amount of liquid nitrogen. Liquid nitrogen
had previously been delivered by commercial trailers, one arriving
every four hours.
In addition to meeting the specifications of the Tevatron, designers
of the magnet and cryogenic systems devised safety measures to manage
three awesome sources of stored energy that could destroy the machine.
First, the Tevatron's magnets store as much as 400 million joules of
energy, equivalent to about 1,000 sticks of dynamite. Second, the
beam accelerated by the Tevatron to 1 TeV is equivalent to more than
10 million joules, enough to drill a hole through the surrounding
magnet. Third, the magnets require 25,000 liters of liquid helium,
which could rapidly expand to 50 million liters of gas, enough to fill
a blimp as long as a football field and five stories high. Each of
these energy sources raises a host of terrifying engineering problems.
For instance, if a tiny fraction of the particle beam hit several
superconducting wires, the particles could heat the wires enough to
cause them to cease superconducting, a process known as quenching.
The wires would then resist the flow of electricity, dissipate power
and consequently heat themselves and adjacent wires to even higher
temperatures. Hence, the enormous energy stored in the magnetic field
could be released, heating the helium and expanding it in pipes at
explosive rates. To protect against such a disaster, Fermilab
designed an automatic shutdown procedure, which would in rapid
sequence extract the beam from the machine, drain the currents from
the magnets and vent the evaporating helium into a large pipe.
In June of 1982 Fermilab suspended operation of the Main Ring, and
Peter J. Limon, C. Thornton Murphy and Laurence D. Sauer began
supervising the orchestrated chaos involved in assembling the
Tevatron. At the peak of activity, some 200 technicians, welders,
electricians, engineers and physicists occupied the tunnel. All the
resources of Fermilab were focused on fabricating the 1,200
superconducting devices as well as the associated power supplies,
utility components, refrigerators and cryogenic conections.
After workers assembled all the parts, made all the connections and
sealed all the leaks, they cooled the magnets to an operating
temperature of 4.7 kelvins. In June of 1983 Fermilab injected the
first bunch of protons from the Main Ring into the Tevatron.
As the Tevatron began demonstrating its power, Fermilab focused its
attention on the antiproton source and the detector for the
proton-antiproton collider. John People, jr., managed the antiproton
source project along with his systems chiefs, John D. McCarthy, Gerald
Dugan, Stephen Holmes and Ernest Malamud. Their ambitious goal was to
build a facility that would produce, collect and store at least 10
billion antiprotons per hour so that the antiprotons could be injected
into the accelerator in a series of bunches.
Tollestrup and Roy F. Schwitters of Harvard University supervised the
development of the Collider Detector at Fermilab (CDF) until 1988,
when Schwitters left to direct the Superconducting Supercollider
Laboratory in Dallas and was replaced by Melvyn J. shochet of the
University of Chicago. More than 200 scientists--including workers
from 10 universities, national laboratories and institutions in Japan
and Italy--helped to build the detector.
CDF could be characterized as a 5,000-ton Swiss watch. It represents
a state-of-the-art device for examining more than 100,000 collisions
per second. The energies of the resulting particles are measured by
numerous heat sensors; the particles' trajectories are recorded by a
wire mesh that carries the electric pulses produced when charged
particles pass nearby. For each of the 30 or more particles produced
in a typical collision, CDF produces more than 10,000 bits of
information about its trajectory and energy. In more than 100 billion
collisions it examined, CDF selected for detailed analysis about five
million events that were of "more than routine interest."
The Tevatron, the antiproton source and CDF were baptized in a series
of experiments that began in January of 1987. These systems required
the most sophisticated choreography of accelerator rings ever
attempted. The procedure for accelerating particles in the Tevatron
is reminiscent of a NASA launch. Control room technicians review an
elaborate checklist before they initiate the process that ends in
In the first step, negative hydrogen ions composed of two electrons
and one proton are released in a device called a Cockroft-Walton
accelerator, which produces an electromagnetic field to propel the
ions to an energy of 750,000 electron volts. The ions then enter a
150-meter-long linear accelerator. By inducing an oscillating
electric field between a series of electrodes, the linear accelerator
boosts ions to an energy of 200 million electron volts. The ions then
pass through a carbon foil, extracting the protons from the ions.
In the second step, the protons are guided into the Booster, a
synchrotron 500 meters in circumference, where the energy is raised to
8 GeV. The protons are then injected into the Main Ring. Here more
than 1,000 conventional, copper-coiled magnets continuously guide and
In the third step, protons are focused into short bunches at 120 GeV.
They are then extracted from the Main Ring and strike a copper target,
producing antiprotons. About 20 million antiprotons can be collected
from each pulse. The antiprotons are then focused by a lithium
lens--a cylinder of liquid lithium that transforms a current pulse of
600,000 amperes into a focusing magnetic field.
In the fourth step, the lithium lens directs the antiprotons to the
first antiproton storage ring, known as the Debuncher, which is about
520 meters in circumference. The Debuncher is designed to squeeze the
antiprotons into as compact a "space" as possible. One can begin to
understand how the Debuncher works if one can imagine sitting on an
antiproton in the middle of a bunch. From this interesting but
precarious vantage point, one can see other antiprotons--some racing
faster, some moving slower and some oscillating from side to side.
All in all, the antiprotons take up a great deal of space, making it
difficult to manipulate the assembly and add more antiprotons.
To increase the density of antiprotons, the Debuncher uses two cooling
processes. The first, called debunching, is a Fermilab innovation.
As a bunch of antiprotons circulates around the ring, a complex,
computer-coded radiofrequency voltage speeds up slower particles and
slows down faster ones, thereby decreasing the energy distribution of
the stored beam. The other process, stochastic cooling, decreases the
side-ways motion of antiprotons. In this method, particles whose
orbits are far from ideal are identified by sensors, which then send
correction signals to kicker electrodes that adjust the paths of the
After the Debuncher squeezes the beam in energy and size, the fifth
step begins: it sends about 20 billion antiprotons per hour to a
concentric ring called the Accumulator. Several independent systems
in the Accumulator cool the beam of antiprotons further, ultimately
increasing the density of antiprotons by a factor of one million.
After four hours, the accumulator ring contains some 200 billion
antiprotons, enough for a "shot" to the Main Ring.
Meanwhile, during the fourth and fifth steps, the Main Ring
accelerates 500 billion protons to 150 GeV. The protons are then
transferred to the Tevatron ring where they await the antiprotons.
In the sixth step, a portion of the stored antiproton beam is
transferred to the Main Ring. The antiprotons are boosted to 150 GeV
in the Main Ring and then injected into the Tevatron ring where
protons have patiently been circulating. Because the protons are
positively charged and the antiprotons are negatively charged, the
protons circulate in a direction counter to that of the antiprotons.
The antiproton bunches pass through the proton bunches many times, but
at this stage the bunches are much too diffuse for significant
collisions to take place.
During the first 60 seconds of the final step, both bunches of
particles are accelerated to full energy. Strong quadrupole magnets
in the Tevatron's ring then squeeze the particles together. During
this stage the delicate stability of the circulating bunches can
easily be disrupted, scattering particles everywhere. If all goes
well, the beams are focused down to a diameter of about 0.1
millimeter, comparable to the diameter of a human hair. The focusing
greatly increases the density of each bunch. Each time the bunches
cross, there is now a 50 percent chance that a single proton will
collide with a single antiproton. According to the original design,
more than 50,000 collisions per second should take place in the center
of the particle detector.
The first series of collider experiments ended in May 1987, and a
second series was started in July 1988 and ran for 11 months. During
that period the Tevatron achieved a collision energy of 1.8 TeV. The
collision rate improved from a few hundred per second to 120,000 per
second, more than twice the design rate. The Tevatron produced a
total of about 100 billion collisions between protons and antiprotons.
Furthermore, it could sustain a beam of circulating particles for as
long as 20 hours, but over time the beams would slowly decrease in
size and density as they were scattered by residual gases in the
vacuum tube and by other effects that are not yet understood. The
Tevatron accomplished these feats using only 20 megawatts of power (as
compared with Fermilab's consumption of 60 megawatts in 1979).
One of the most satisfying aspects of these first experiments was to
confirm the hypothesis that proton-antiproton collisions can be
analyzed in a straight-forward manner. This hypothesis is not obvious
when one considers that the proton is a mess: it is composed of three
quarks and many force-carrying particles called gluons. The
antiproton is, similarly, an antimess. It seemed plausible that a
collision between a proton and an antiproton could have produced an
indecipherable hodgepodge in which most particles would mask the
interesting behavior of others. It turned out, however, that most
particles produced in the collision were so low in energy as to be
mere spectators of the main events. Only a few high-energy particles
emerged, indicating a clean collision between one quark in a proton
and another quark in an antiproton.
A variety of high-energy particles can be resolved by CDF. Electrons,
muons and photons are easily identified by their trajectories and
energies. The quarks appear as jets, that is, bundles of pions,
protons, neutrons and kaons. Short-lived particles such as W and Z
also decay into a recognizable spray. In many cases, neutrinos, which
are not recorded by CDF, can be located by noting "missing" momentum.
By the end of 1990, Fermilab investigators had published some 25
papers. These detailed such new insights as the size of quarks, the
nature of the weak and electromagnetic forces, the properties of
"bottom" quarks and the lower limit of the mass of the top quark.
The Standard Model assumes that quarks are truly fundamental: they
have neither structure nor spatial dimension; they are point particles
with no radius. If so, quarks should scatter off one another in
different ways than they would if they have a finite radius or any
type of structure. Investigators may be able to determine whether
quarks have structure, therefore, by studying the distribution of jets
produced in collisions between quarks. So far the results from CDF
agree with the Standard Model. If quarks do have a finite radius, it
is less than 2 X [10.sup.19] meters (that is, at least 4,000 times
smaller than the radius of a proton).
To determine crucial parameters of electromagnetic and weak forces,
Fermilab has studied the masses and decay properties of the [W.sup.+],
[W.sup.-] and [Z.sup.0] particles. Although the 1987 results from CDF
gave the most precise value for the [Z.sup.0] mass, this was very soon
superseded by the "Z" factories, Stanford's and CERN's
electron-positron colliders. On the other hand, CDF supplemented by
results from the CERN proton-antiproton collider provides the primary
data on W properties.
In the past two decades, physicists have come to recognize that the
weak and electromagnetic forces are expressions of a more profound
interaction now designated the electroweak force. Fermilab has
precisely measured a crucial parameter of the electroweak force, the
so-called weak mixing angle. This parameter essentially describes the
relative strengths of the electromagnetic and the weak forces in their
Fermilab has recently reported exciting evidence for the production of
B mesons (particles made of a bottom quark and an antidown or
antistrange quark). The run in 1989 recorded about as many B meson
events as those observed in all the electron-positron colliders
combined. The 1991 run should increase the yield by 100 times in the
Physicists generally believe that a detailed study of the decay of B
mesons will lead to a better understanding of the origin of matter.
In recent years we have learned that the origin of matter in the early
universe was derived from a tiny violation of a deep symmetry of
matter and antimatter, known as the charge-parity symmetry. Hence,
the study of this symmetry violation in B mesons will be a major focus
of Tevatron during the next decade.
One of Fermilab's highest priorities has been to search for events
that would suggest the production and decay of a top quark. So far
CDF has observed only one dubious event. Applying theoretical
predictions for the number of events that should have been observed in
the CDF data for any assumed mass of the top quark, CDF concluded that
the mass of the top quark is greater than 90 GeV.
Why is the top quark so much heavier than its closest relative, the
5-GeV bottom quark? The answer is connected to the most interesting
issue in particle physics--the nature of mass and the mechanisms by
which the particles of matter acquire mass. The most elegant theories
predict that the quarks should have small or vanishing mass. Is the
top quark just an anomalously heavy spectator, or is it the key to the
internal structure of the Standard Model? The Tevatron is now the
only accelerator in the world that can address this issue. In the
next decade CDF is planning to increase its sensitivity gradually to
find the top quark.
During the past six years, while Fermilab developed and used the
Tevatron collider, it continued to produce important results with the
fixed-target program. Here the power of the Tevatron was used to
create beams of muons, neutrinos, pions and other particles. The
Tevatron's high energy and superior time structure have yielded data
of unequaled precision for more than 20 experiments.
One of the most interesting examples is the research on the properties
of particles carrying the "charm" quark. In a 1987 run, this
experiment amassed more fully analyzed charm events than had
previously been collected by all the world's facilities since the
charm quark was discovered in 1975. The result was a bonanza of data
on lifetimes, new states and modes of decay.
The Tevatron entered final phase of its program in July 1989, when I
retired as director of Fermilab and was succeeded by John Peoples, Jr.
The program, called Fermi III, includes, notably, a more powerful
linear accelerator and a new Main Ring to inject particles into the
Tevatron. Fermi III should improve the collision rate of the Tevatron
from 120,000 per second to more than six million per second. Because
of these improvements, by 1996 the Tevatron should be sensitive to a
top quark with a mass as high as 250 GeV.
Fermi III also plans to complete a second detector called DZERO for
experiments to begin in 1992. DZERO incorporates a great deal of the
experience acquired by CERN in its pioneering proton-antiproton
research. Paul D. Grannis of the State University of New York at
Stony Brook and H. Eugene Fisk of Fermilab led the DZERO project and
enjoyed assistance from some 17 U.S. and foreign institutions. As the
detectors are gradually improved to match the machine's performance,
the Tevatron will seek again to peer inside the quark and the
electron, and it will subject the Standard Model to tests of great
Fermilab's pioneering efforts in superconducting magnet technology
will strongly influence the future of accelerators. Several machines
will soon use superconducting magnet tehcnologies, including, this
year, the 800-GeV proton ring at the DESY laboratory and, in 1995, a
3-TeV proton accelerator at the Soviet accelerator laboratory at
Serpukhov. The most dramatic occurrence, however--certainly from the
perspective of the U.S.--is the decision to build the Superconducting
Supercollider. It will use 10,000 superconducting magnets in a pair
of 20-TeV proton rings.
As the Tevatron program enters its second decade, it maintains an
approach consistent with Fermilab's founding philosophy: the
laboratory exists to serve the university science community. It is
important to point out that they typical university group that
collaborates at Fermilab is about the same size as those that do
experimental science anywhere in the university. Fermilab and other
"big science" projects should be judged on the scientific value of
their work and the opportunities they provide to both experienced
professors and young investigators. Oceanographers, astronomers,
genome biologists and particle physicists have been wrestling with the
problem of managing large, shared facilities for some time. We must
learn to cope with the human problems, particularly the preservation
of creativity and initiative, if we are to continue to probe nature's
LEON M. LEDERMAN is former director of the Fermi National Accelerator
Laboratory (Fermilab) and holds the Frank E. Sulzberger Professorship
at the University of Chicago. In 1951 he received his Ph.D. from
Columbia University. He managed Columbia's Nevis Laboratories from
1962 until 1979, when he took up his post at Fermilab. He shared the
1988 Nobel Prize in Physics for the discovery of the muon neutrino.
He is one of the founders of the Academy for Mathematics and Science
Teachers, an institutions for improving education in kindergarten
through 12th grade.
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