The Pentagon's pursuit of a new kind of nonnuclear super-weapon has sparked a behind-the-scenes revolt among its elite scientific advisers, some of whom reject the scheme as pseudoscience.
The military's goal is to develop a bomb that might be far more powerful than existing conventional weapons of the same size. Precisely targeted, such a weapon could take out targets -- such as underground caverns that conceal weapons of mass destruction -- without posing the severe political risks of using nuclear bombs.
The key to the concept is a little known element called hafnium. By figuring out how to unleash the abundant energy from a hafnium isotope, called hafnium-178, the military hopes to develop a new generation of weapons. According to a Defense Department Web site, such a weapon might "revolutionize all aspects of warfare."
The Pentagon is now quietly investigating ways to mass produce the isotope. Late last year, it created the 12-member Hafnium Isomer Production Panel (HIPP). Its purpose: to assess ways to mass-produce the isotope for military uses ranging from bombs to advanced forms of propulsion.
Yet some of the nation's most distinguished scientists and military advisers say that such futuristic dreams of tomorrow's battlefields are premature at best and nonsense at worst.
For four years, working largely behind the scenes, they have advised the Pentagon that claims by hafnium-178 enthusiasts -- led by physicist Carl Collins of the University of Texas -- defy sound physical theory and have not been reproduced in lab experiments by other researchers. For the first time, some of these skeptics are going public with their concerns.
Last month, in a memorandum to Pentagon and Energy Department officials obtained by The Chronicle, five of the 12 members of the military's own advisory panel on mass producing hafnium-178 and other top experts warned against prematurely proceeding to develop weapons "applications that may not make physical sense."
"In my opinion, this matter is worse than cold fusion," said panel member Bill Herrmannsfeldt, referring to unconfirmed claims by scientists in the 1980s that they had generated nuclear fusion energy at low temperatures. Herrmannsfeldt, a physicist at the Stanford Linear Accelerator Center, is leading a revolt against hafnium-178 weapons work within HIPP itself.
Although Herrmannsfeldt regards claims for hafnium-178's super-energy powers as nonsense, he fears that other nations will take them seriously, triggering a new arms race. Recently, he successfully urged numerous top scientists to co-sign a letter to Washington officials citing experts' reservations about the scientific credibility of hafnium-178 claims and asking for a review of those claims by independent experts.
HIGHLY RESPECTED SKEPTICS
Among the signatories to the Aug. 13 letter to officials at the Defense Advanced Research Projects Agency (DARPA) and the U.S. Energy Department are Stanford's Wolfgang Panofsky and Sidney Drell, both grand old men of the American weapons advisory establishment.
The letter urges the federal government to create an independent panel to resolve the scientific community's dispute over claims made for the hafnium-178 "nuclear isomer," as it's called. The government should do so, they stress, before spending any more money to develop weapons "applications that may not make physical sense."
Jan Walker, a spokeswoman for DARPA at its Arlington, Va., headquarters, said the agency is reviewing the letter but declined to discuss the issue.
Walker noted that in conducting advanced research and technology development for the Defense Department, DARPA has been involved in producing the technical underpinnings of the Internet, the stealth fighter and bomber, and unmanned air vehicles such as Global Hawk and Predator.
Some isotopes can experience high-energy, or "nuclear isomer," states in which they retain abnormal amounts of energy. One of these isotopes is hafnium-178; its nuclear-isomer state is technically known as hafnium-178m2.
Normally, this nuclear isomer has a half-life of 31 years, meaning half of it decays away in 31 years. That's way too slow to heat and ignite a firecracker, much less a super-bomb.
Hafnium is a bright, natural metal. For weapons purposes, the Pentagon would need large quantities of the particular type called hafnium-178. The known amount of hafnium-178 nuclear isomer in the world is so small that the Pentagon would have to mass produce it. No one has a good idea how. The Pentagon appointed the HIPP panel to try to find out.
One possible way would involve bombarding elements in a giant particle accelerator, then developing a tedious process for extracting the hafnium-178 nuclear isomer. Some scientists are skeptical that such a technique could be developed cost effectively -- even if hafnium-178 nuclear isomer proves to be an exotic energy source as Collins and his colleagues have speculated.
In January 1999, an international team led by Collins claimed it had unleashed startling amounts of energy -- far more than theoretically expected -- from the hafnium-178 isomer. They did so, they reported in the journal Physical Review Letters, by bombarding the isotope with X-rays from an ordinary dental X-ray machine.
Besides Collins, the article's 13 co-authors included scientists at the U.S. Air Force Research Laboratory in Albuquerque; Russia's Joint Institute for Nuclear Research; and Sandia National Laboratories, a nuclear weapons lab in New Mexico. Collins himself has a weighty reputation. A decade earlier, the Texas Academy of Sciences had named him "Distinguished Texas Scientist" of the year for his research on high-energy lasers.
Elsewhere, other scientists tried to replicate Collins' work by bombarding the isotope with radiation from large particle accelerators, which are far more powerful than the Collins team's dental X-ray machine. Results: negative.
One of Collins' original collaborators on the 1999 paper, nuclear physicist James Carroll of Youngstown State University, has since been unable to replicate the Collins experiment on his own. He suspects the energy-unleashing process "is more complex than (Collins) originally thought and needs further study," Carroll said in an interview.
Furthermore, scientists from Lawrence Livermore National Laboratory, Los Alamos National Laboratory and Argonne National Laboratory found "no evidence" of unusual energy emissions from hafnium-178 exposed to X-rays at Argonne's hefty Advanced Photon Source accelerator, they reported in Physical Review Letters in 2001.
The hafnium-178 controversy was also investigated by the members of "Jason," which has functioned for decades as a kind of supreme advisory council of military science. Mostly distinguished physical scientists based at universities and private companies, these scholars -- often collectively known as "the Jasons" -- use their expertise to critique the Pentagon's more ambitious schemes for expensive, futuristic weapons.
Claims that hafnium-178 can unleash intense energy are based on experiments that are "poorly characterized and ill-described," Jason member Steve Koonin wrote in 1999, summarizing the group's findings in a letter to the U.S. Arms Control and Disarmament Agency. The claims are "a priori implausible -- extraordinary claims demand extraordinary proof," but that's lacking so far, added Koonin, a nuclear physicist and provost of the California Institute of Technology.
"It is extraordinarily unlikely that there is something here" that portends a new generation of futuristic weapons, Koonin said in a phone interview. However, he noted that Collins and others have reported new results since 1999, and that he'd support a new Jason analysis if the Pentagon or Energy Department requested it.
Collins has stuck to his guns. In a number of e-mail responses to a Chronicle inquiry, he compared the critics to early 20th century naysayers who denied the feasibility of atomic energy.
Collins insists his findings have "been confirmed at about all of the world's third-generation (most advanced) synchrotron radiation sources, except the DOE facility at Argonne. . . . Naturally, that causes controversy, but it is a strength of the scientific method that continued study and measurement will resolve the controversy."
One reason some critics have been unable to verify his original claim, Collins said, is that their instrument was "blind" to one of the spectral lines, the so-called 130 line, that he used in measuring energy from hafnium-178. Hence, "they could not possibly have seen the results" even "if they had succeeded in doing it."