SF Chron: Air Force pursuing antimatter weapons

[Dave Farber <dave () farber net>]

From: Paul Saffo <psaffo () iftf org>
To: Dave Farber <dave () farber net>
Date: Mon, 04 Oct 2004 07:34:19 -0700
Subj: SF Chron: Air Force pursuing antimatter weapons

Posted without comment.
-p

Air Force pursuing antimatter weapons
  Program was touted publicly, then came official gag order
  - Keay Davidson, Chronicle Science Writer
  Monday, October 4, 2004


The U.S. Air Force is quietly spending millions of dollars  
investigating ways to use a radical power source -- antimatter, the  
eerie "mirror" of ordinary matter -- in future weapons.

  The most powerful potential energy source presently thought to be  
available to humanity, antimatter is a term normally heard in  
science-fiction films and TV shows, whose heroes fly  
"antimatter-powered spaceships" and do battle with "antimatter guns."

  But antimatter itself isn't fiction; it actually exists and has been  
intensively studied by physicists since the 1930s. In a sense, matter  
and antimatter are the yin and yang of reality: Every type of subatomic  
particle has its antimatter counterpart. But when matter and antimatter  
collide, they annihilate each other in an immense burst of energy.

  During the Cold War, the Air Force funded numerous scientific studies  
of the basic physics of antimatter. With the knowledge gained, some Air  
Force insiders are beginning to think seriously about potential  
military uses -- for example, antimatter bombs small enough to hold in  
one's hand, and antimatter engines for 24/7 surveillance aircraft.

  More cataclysmic possible uses include a new generation of super  
weapons -- either pure antimatter bombs or antimatter-triggered nuclear  
weapons; the former wouldn't emit radioactive fallout. Another  
possibility is antimatter- powered "electromagnetic pulse" weapons that  
could fry an enemy's electric power grid and communications networks,  
leaving him literally in the dark and unable to operate his society and  
armed forces.

  Following an initial inquiry from The Chronicle this summer, the Air  
Force forbade its employees from publicly discussing the antimatter  
research program. Still, details on the program appear in numerous Air  
Force documents distributed over the Internet prior to the ban.

  These include an outline of a March 2004 speech by an Air Force  
official who, in effect, spilled the beans about the Air Force's high  
hopes for antimatter weapons. On March 24, Kenneth Edwards, director of  
the "revolutionary munitions" team at the Munitions Directorate at  
Eglin Air Force Base in Florida was keynote speaker at the NASA  
Institute for Advanced Concepts (NIAC) conference in Arlington, Va.

  In that talk, Edwards discussed the potential uses of a type of  
antimatter called positrons.

  Physicists have known about positrons or "antielectrons" since the  
early 1930s, when Caltech scientist Carl Anderson discovered a positron  
flying through a detector in his laboratory. That discovery, and the  
later discovery of "antiprotons" by Berkeley scientists in the 1950s,  
upheld a 1920s theory of antimatter proposed by physicist Paul Dirac.

  In 1929, Dirac suggested that the building blocks of atoms --  
electrons (negatively charged particles) and protons (positively  
charged particles) -- have antimatter counterparts: antielectrons and  
antiprotons. One fundamental difference between matter and antimatter  
is that their subatomic building blocks carry opposite electric  
charges. Thus, while an ordinary electron is negatively charged, an  
antielectron is positively charged (hence the term positrons, which  
means "positive electrons"); and while an ordinary proton is positively  
charged, an antiproton is negative.

  The real excitement, though, is this: If electrons or protons collide  
with their antimatter counterparts, they annihilate each other. In so  
doing, they unleash more energy than any other known energy source,  
even thermonuclear bombs.

  The energy from colliding positrons and antielectrons "is 10 billion  
times ... that of high explosive," Edwards explained in his March  
speech. Moreover, 1 gram of antimatter, about 1/25th of an ounce, would  
equal "23 space shuttle fuel tanks of energy." Thus "positron energy  
conversion," as he called it, would be a "revolutionary energy source"  
of interest to those who wage war.

  It almost defies belief, the amount of explosive force available in a  
speck of antimatter -- even a speck that is too small to see. For  
example: One millionth of a gram of positrons contain as much energy as  
37.8 kilograms (83 pounds) of TNT, according to Edwards' March speech.  
A simple calculation, then, shows that about 50-millionths of a gram  
could generate a blast equal to the explosion (roughly 4,000 pounds of  
TNT, according to the FBI) at the Alfred P. Murrah Federal Building in  
Oklahoma City in 1995.

  Unlike regular nuclear bombs, positron bombs wouldn't eject plumes of  
radioactive debris. When large numbers of positrons and antielectrons  
collide, the primary product is an invisible but extremely dangerous  
burst of gamma radiation. Thus, in principle, a positron bomb could be  
a step toward one of the military's dreams from the early Cold War: a  
so-called "clean" superbomb that could kill large numbers of soldiers  
without ejecting radioactive contaminants over the countryside.

  A copy of Edwards' speech onNIAC's Web site emphasizes this advantage  
of positron weapons in bright red letters: "No Nuclear Residue."

  But talk of "clean" superbombs worries critics. " 'Clean' nuclear  
weapons are more dangerous than dirty ones because they are more likely  
to be used," said an e-mail from science historian George Dyson of the  
Institute for Advanced Study in Princeton, N.J., author of "Project  
Orion," a 2002 study on a Cold War-era attempt to design a nuclear  
spaceship. Still, Dyson adds, antimatter weapons are "a long, long way  
off."

  Why so far off? One reason is that at present, there's no fast way to  
mass produce large amounts of antimatter from particle accelerators.  
With present techniques, the price tag for 100-billionths of a gram of  
antimatter would be $6 billion, according to an estimate by scientists  
at NASA's Marshall Space Flight Center and elsewhere, who hope to  
launch antimatter-fueled spaceships.

  Another problem is the terribly unruly behavior of positrons whenever  
physicists try to corral them into a special container. Inside these  
containers, known as Penning traps, magnetic fields prevent the  
antiparticles from contacting the material wall of the container --  
lest they annihilate on contact. Unfortunately, because like-charged  
particles repel each other, the positrons push each other apart and  
quickly squirt out of the trap.

  If positrons can't be stored for long periods, they're as useless to  
the military as an armored personnel carrier without a gas tank. So  
Edwards is funding investigations of ways to make positrons last longer  
in storage.

  Edwards' point man in that effort is Gerald Smith, former chairman of  
physics and Antimatter Project leader at Pennsylvania State University.  
Smith now operates a small firm, Positronics Research LLC, in Santa Fe,  
N.M. So far, the Air Force has given Smith and his colleagues $3.7  
million for positron research, Smith told The Chronicle in August.

  Smith is looking to store positrons in a quasi-stable form called  
positronium. A positronium "atom" (as physicists dub it) consists of an  
electron and antielectron, orbiting each other. Normally these two  
particles would quickly collide and self-annihilate within a fraction  
of a second -- but by manipulating electrical and magnetic fields in  
their vicinity, Smith hopes to make positronium atoms last much longer.

  Smith's storage effort is the "world's first attempt to store large  
quantities of positronium atoms in a laboratory experiment," Edwards  
noted in his March speech. "If successful, this approach will open the  
door to storing militarily significant quantities of positronium  
atoms."

  Officials at Eglin Air Force Base initially agreed enthusiastically to  
try to arrange an interview with Edwards. "We're all very excited about  
this technology," spokesman Rex Swenson at Eglin's Munitions  
Directorate told The Chronicle in late July. But Swenson backed out in  
August after he was overruled by higher officials in the Air Force and  
Pentagon.

  Reached by phone in late September, Edwards repeatedly declined to be  
interviewed. His superiors gave him "strict instructions not to give  
any interviews personally. I'm sorry about that -- this (antimatter)  
project is sort of my grandchild. ...

  "(But) I agree with them (that) we're just not at the point where we  
need to be doing any public interviews."

  Air Force spokesman Douglas Karas at the Pentagon also declined to  
comment last week.

  In the meantime, the Air Force has been investigating the possibility  
of making use of a powerful positron-generating accelerator under  
development at Washington State University in Pullman, Wash. One goal:  
to see if positrons generated by the accelerator can be stored for long  
periods inside a new type of "antimatter trap" proposed by scientists,  
including Washington State physicist Kelvin Lynn, head of the school's  
Center for Materials Research.

  A new generation of military explosives is worth developing, and  
antimatter might fill the bill, Lynn told The Chronicle: "If we spend  
another $10 billion (using ordinary chemical techniques), we're going  
to get better high explosives, but the gains are incremental because  
we're getting near the theoretical limits of chemical energy."

  Besides, Lynn is enthusiastic about antimatter because he believes it  
could propel futuristic space rockets.

  "I think," he said, "we need to get off this planet, because I'm  
afraid we're going to destroy it."

  E-mail Keay Davidson at kdavidson () sfchronicle com.

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