Saturday, June 14, 2008

Hafnium-178=isomer bomb

Buck Rogers' "ray gun"? The story below is the stuff for a science fiction story. What a story: Science on a shoestring budget, Cold War science of the nuclear arms race, military investments, a subtle way of skirting nuclear arms treaties by developing a new type of nuclear weapon. Read the following story by Sharon Weinberger and meet the "isomer bomb".

"Scary Things Come in Small Packages"

The Pentagon says what Carl Collins is cooking up in his lab could power the most devastating bomb this side of a nuke. A long list of heavyweight physicists calls that dangerous bunk.


Sharon Weinberger

March 28th, 2004

Washington Post

It came from Los Alamos, express delivery. Refined, processed and sealed in plastic, it looked more like the grime that clings to the car after a hard winter than something that might cost as much as $28 billion an ounce.

In a barnlike lab at the University of Texas at Dallas, among massive accelerators, old pieces of cannibalized metal, layers of dust, broken knobs, bits of wire and discarded electronics, the precious material was placed atop an upside-down Styrofoam coffee cup.

A dental X-ray machine -- the kind used in hundreds of strip malls around the country -- focused on the cup. A man with a radiation tag on his shirt flipped a switch. A few days passed. To the naked eye, nothing happened. But during that time an invisible X-ray beam, modulated by a commercial audio amplifier, slammed into the minute amount of material on the Styrofoam platform. Protected behind cinder blocks, a flickering computer screen registered jagged graphs.

And just like that, physicist Carl Collins either proved he was on the way to the next Manhattan Project, or perhaps proved nothing at all.

That was 1998. Six years later, a scientific dogfight rages over Collins's result. Was it really the beginning of a new super-bomb, or the biggest fizzle since cold fusion?

But the Pentagon hasn't waited for the dust to settle. Despite increasingly outraged protests by some of the country's most respected nuclear physicists, the Department of Defense has sunk millions into something that sounds to some like science fiction: Collins's efforts to get near-nuclear-level energy from a rare radioactive element without splitting any atoms.

As the debate has raged, a defense official has been promoting Collins's work with a picture of a "nuclear hand grenade," some agencies have promised an entirely new class of "isomer weapons," and the Central Intelligence Agency and the military have raised fears that the Russians might get there first.

The Big Pop

Although he didn't know it at the time, Carl Collins began his pursuit of isomer weapons in Romania. It was 1978, the height of the Cold War. While the nuclear physicists of the world's leading laboratories and universities attended meetings in Paris and London, Collins spent the better part of a decade in Bucharest working with scientists behind the Iron Curtain.

He ended up marrying a Romanian and, with his East European colleagues, began trying to tap a possibly immense source of energy from an atom with a hopped-up nucleus called an isomer.

In the simplest conception, imagine the nucleus of an atom as a deflated balloon. Blow up the balloon and tie it at the end, and you have a nuclear isomer -- the same balloon, but now filled with the stored energy of the enclosed air. Under ordinary circumstances, the filled balloon will gradually lose air, and pressure, from slow leakage.

The energy that isomers "leak" is in the form of gamma rays. Gamma rays are the most energetic wavelength on the electromagnetic spectrum. In extremely high doses, they could act like ray bombs in low-budget films, vaporizing living tissue and heating materials until they explode.

And theoretically that's what would happen if you could find a way to release all of an isomer's energy in an instant, like popping the balloon with a pin.

This, very crudely, was what Collins and his colleagues were attempting -- they wanted to use a small amount of energy to release a large amount of energy; they were looking for the pin that could pop the balloon. The potential was immense: Instead of the approximately one electron volt of energy stored in a single molecule of dynamite, each atom of the isomer Collins's group would eventually use could store 2.5 million electron volts.

Collins called the process "isomer triggering." His first attempts involved tantalum-180 -- the only naturally occurring nuclear isomer. The idea, roughly, was that he could use a beam of energy to act like a spark igniting dynamite. He eventually concluded that you could release energy from tantalum -- something that most physicists concede is possible -- but it required far more energy to "trigger" tantalum than the isomer released. In other words, there was no gain in energy, and thus there were no applications.

But Collins looked at his tantalum experiment as proving that triggering could work, and the issue was just a matter of finding a different, better isomer.

His belief in the potential of the right isomer was persuasive enough that, in the 1980s, when President Ronald Reagan announced his Strategic Defense Initiative (what became known as the Star Wars program), Collins's project got substantial Pentagon funding in the hopes that isomer triggering would become the energy source for a powerful gamma-ray laser, a weapon that might vaporize incoming missiles in outer space. But when the space-based Star Wars fell by the wayside in the 1990s -- too expensive and technologically uncertain -- Collins was left to carry on in obscurity.

Which Collins and his colleagues did, performing thousands of experiments over the span of a decade to find the best candidate for isomer triggering. In 1995, at a NATO workshop on isomers attended by Ukrainian and Russian scientists who had been conducting gamma-ray research during the Cold War, a consensus emerged that the isomer should be hafnium-178. A small supply had been found in minute quantities as an unintended byproduct of a Los Alamos accelerator. One ounce of hafnium-178 stores enough energy to boil 120 tons of water. One tankful of it could fuel a car on a trip around Earth 520 times. And, most to the point, one gram of the material would have up to 50,000 times the explosive power of a gram of TNT.

A Bomb And A Prayer

Collins's lab -- at the far edge of the University of Texas at Dallas campus -- gives no hint of its dramatic mission. Its entrance is marked only with the Greek letter g, the scientific symbol for gamma rays, and outside there's a sign made from a discarded highway marker.

It was here, in the summer of 1998, that Collins and his group hooked up the dental X-ray machine and fired it at the hafnium sample. Today, the head of a similar X-ray machine, still attached to its swivel arm, sits discarded on the floor. The original audio amplifier, which Collins describes as the "type used in rock concerts," remains encased in concrete below the test bed, its final burying place.

Back in the office, behind a glass case, is the original Styrofoam cup, marked "Dr. C's memorial target holder," and next to it sits a second, identical cup ironically labeled "A cheap imitation."

The jury-rigged equipment is a testament to the resourcefulness of Collins's graduate students, the kind that only the command economies of communist Eastern Europe could have produced. A few of Collins's students picked up the X-ray machine from a dental-salvage business with a little sweet-talking and $1,500. Another student came up with the idea of using the 5-kilowatt amp to modulate the energy output.

The X-ray machine was left beaming on the hafnium for several weeks through a series of tests. There was no flash and bang -- even if hafnium proved to be everything Collins hoped it was, the microscopic sample's energy would be visible only to the most sensitive instruments. Instead, there was the painstaking recording and analysis of gamma-ray levels. Hafnium-178 has a half-life of 31 years, which means it gives off half of its stored energy over three decades. What Collins was looking for was clear evidence that his X-rays were accelerating that process, even a little bit.

Nothing about making the measurements or analyzing them was easy. It involved probability and margins of error, and required careful scientific rigor. But in a subsequent 1999 article in the respected scientific journal Physical Review Letters, Collins wrote that the experiment had been successful. The results were unambiguous, he claimed. He had been able to "trigger" the release of energy.

Among nuclear physicists, those results were met with some curiosity, some doubt and a great deal of ridicule. The results Collins claimed were absurdly out of whack with what conventional physics would allow for hafnium.

Critics also challenged his statistical accuracy, the high margin of error he reported and the overall significance of his results. Collins responded that the history of experimental physics was filled with examples of naysaying theoreticians being proved wrong. He dismissed the criticism as "judgmental opinion" and "logical fallacy."

But as the scientists fought out isomer triggering in the pages of Physical Review Letters, a number of dedicated isomer believers set out to show that Collins's results could be harnessed as a weapon. The isomer bomb began its roller-coaster ride from a controversial experiment in a relatively unknown science center to the inner sanctum of the military -- the E-Ring of the Pentagon. All it took was five years, an administration preoccupied with the war on terror, a new wellspring of support for nuclear and nuclear-type weapons, and an agency willing to ignore its own advisers.

Do You Believe In Isomers?

Based on Collins's reported success in the 1998 triggering, the Air Force moved in to support his work. Meanwhile, Pat McDaniel, an Air Force researcher who collaborated on the dental X-ray experiment, used his personal contacts to build interest at Sandia National Laboratories in New Mexico.

Sandia, along with Lawrence Livermore National Laboratory in California and Los Alamos National Laboratory in New Mexico, is operated by the Department of Energy. The labs make up the three legs of the U.S. nuclear weapons lab system. (As the "Z Division" of the Manhattan Project -- the super-secret World War II program to develop the atomic bomb -- Sandia was assigned the engineering task of designing and building the weapons, while Livermore and Los Alamos were at the heart of physics work.)

McDaniel found a receptive hearing from his friend and Sandia program manager Nancy Ries. Shortly after the 1998 experiment, Ries and McDaniel started handing out campaign-style buttons that read, "I believe in isomers," according to Peter Zimmerman, then a senior arms control official in the Clinton administration. Ries, McDaniel and intelligence officials began giving briefings touting isomer research as "the best thing for weapons research since sliced bread," Zimmerman said. Hafnium could be used to build a more powerful bomb or, more to the point of what the military was looking for, a small bomb with a huge bang, the believers argued. And even better, building a weapon using hafnium wouldn't violate internationally negotiated restrictions on testing nuclear weapons or congressional limits on developing new nuclear weapons. Because it wouldn't involve splitting atoms, a hafnium bomb would be a totally new class of weapon.

Zimmerman had long heard talk about isomers as a potent energy source for weapons, but had never taken it very seriously. He was well versed in the scientific issues -- with a PhD in nuclear physics. His 30-year career spanned the overlapping worlds of science and national security. The "I believe in isomers" campaign hit him just as he prepared to take over his new job in Foggy Bottom as chief scientist of the Arms Control and Disarmament Agency, whose mission was to both promote arms control and be on the lookout for new developments in weapons. As chief scientist, Zimmerman was responsible for preventing "technological surprise" in the weapons field. Though the science of an isomer bomb seemed to him to be questionable and the promises vastly unrealistic, he couldn't stop thinking about the 1939 decision by the Navy's research laboratory to ignore an Italian-born physicist, Enrico Fermi, who tried to convince the U.S. military that the fascists were working on a new weapon based on nuclear fission. The military thought he was talking science fiction.

Now, with talk of an isomer weapon, Zimmerman said recently, "I had the science fiction reaction, and a rather bad science fiction at that. But what I wanted to know was that if I discouraged DOD from funding it, I wouldn't be like the admiral who turned down Enrico Fermi in 1939."

Zimmerman had somewhere to turn: an elite, secretive group of senior scientists called the Jasons. Thought to be named after the Greek mythical hero Jason, the group of approximately 55 advisers has been around since 1959, most of the time as part of the Defense Advanced Research Proj-ects Agency (DARPA) -- the Pentagon's primary R&D arm. Operating mostly under the radar screen of public view, the Jasons pick their own members from among the nation's top scientists. Often called upon to evaluate controversies beyond the scientific understanding of government officials, the Jasons have weighed in on items ranging from obscure technology to weighty policy issues, and their influence over the years has been enormous. A 1966 report by the Jasons cast doubt on the use of strategic bombing to cut the Viet Cong's supply lines during the Vietnam War. In another report, the Jasons concluded that low-yield nuclear testing wasn't necessary for the United States to maintain a robust stockpile of nuclear weapons, a recommendation that figured prominently in the Clinton administration's support for a moratorium on nuclear testing.

Most important to Zimmerman with regard to the hafnium-triggering experiment, the Jasons had the scientific clout that would allow them to say whether a given scientific pursuit was outright harebrained. Zimmerman asked the Jasons to look at four principal questions: Did Collins indeed demonstrate that an "enhanced decay rate," or triggering, really took place? What is the physical mechanism that would allow the triggering to take place? Could enough hafnium be produced feasibly in the next 20 years to make it useful? Could a triggering mechanism be produced in the next 20 years?

The Jasons' conclusions, reached in July 1999, were damning on all four fronts. In essence, the Jasons concluded that the whole thing didn't pass the "snicker test," according to Zimmerman.

But there was a problem with the Jasons' study. Carl Collins, the man whose science was in question, never spoke to the group.

Even so, the study wasn't just about Collins's work. "Even if you trigger it, you couldn't use it as a weapon," said Steve Koonin, the provost of the California Institute of Technology, who led the Jasons' study. Hafnium-178 emits radiation like crazy; the amount required to fuel a bomb would require so much shielding to protect whoever is around the material that it would defeat the idea of having a small bomb. With the shielding, it wouldn't be such a useful bomb anymore, Koonin said. Finally, even if you could trigger hafnium in a bomb, it would be impossible to "burn" all the hafnium isomer. The resulting explosion, he said, would simply disperse a large amount of highly radioactive material. He paused for a second, and then said, "It sure would make a great dirty bomb."

A hafnium bomb, even if it didn't leave radioactive fallout, still wouldn't be like an ordinary bomb because, along with an explosive force, it would emit intense, penetrating gamma rays. According to Hill Roberts, a scientist at SRS Technologies in Huntsville, Ala., a gamma-ray bomb is appealing to some because gamma rays can pass through solid material and penetrate living tissue. Theoretically, an energetic gamma-ray burst could penetrate bunkers, killing whatever was inside -- be it humans or anthrax stockpiles. Putting it more bluntly, he said, "Tissue turns to goo."

But none of that would matter if an isomer bomb was flat-out impossible. Which was exactly what the Jasons concluded. Zimmerman thought he'd closed the book on the matter, and so did the Jasons.

In fact, the isomer bomb was just getting started.

The Argonne Group

Even if hafnium wasn't going to be a weapon, Collins's claims challenged conventional physics. Which raised a pressing question among government physicists: Could the results of the dental X-ray experiment be reproduced? In fact, the Jasons themselves, while arguing that hafnium couldn't be a weapon, suggested that another triggering experiment be done at a proper X-ray facility.

"When the results of that first paper came out, it seemed strange, and many nuclear physicists said it just couldn't be right," said John Schiffer, a senior scientist at the Argonne National Laboratory's Physics Division in Illinois. "There were some comments published, criticizing the paper, but most people just talked about it as something not to be taken seriously."

But in 2001, two years after Collins's results were published, John Becker, a physicist at the Livermore Lab, decided to do just that. He eventually put together a group of scientists that included Schiffer and 13 other researchers from three of the nation's leading Department of Energy labs: Argonne, Livermore and Los Alamos. The Becker group repeated the experiment using the powerful X-ray source at Argonne, which is the size of a football field and more than 100,000 times more intense than Collins's dental X-ray. According to the scientists who participated, if Collins's results were correct, then their team should have seen a much bigger signal than Collins had reported. But when the Argonne scientists turned on the X-ray, they saw nothing.

Collins's response: The Argonne group had set its X-ray at the wrong energy level. In his first article, Collins didn't specify the exact energy level that triggered the hafnium, he said, because his group learned what it was only after repeating the experiment at an advanced X-ray source in Japan. The scientists led by Becker did a second experiment a year later to attempt the level Collins described. Again, they found nothing.

This time Collins said the failure was the result of other differences in the design of the Argonne experiment. One of the most significant differences, he said, was that the radiation detectors were "blind" to precisely the energy level of gamma-ray emissions present when the isomer was triggered. In a recent interview, he described the members of the Argonne group as "failures," who were unfamiliar with the literature on triggering, inexperienced in the field and ill-equipped to repeat his experiments.

Becker and his colleagues responded by saying that the experimental differences were either irrelevant or untrue. Opinion in the scientific journals favored the Argonne group. In fact, Collins suddenly was no longer able to get published in Physical Review journals. He eventually published in Europhysics Letters, a lesser known journal. In April 2002, Don Gemmell, a physicist from Argonne, wrote to the editor of Europhysics Letters, warning that the journal was in danger of promoting a new "cold fusion" -- the infamous 1980s claim by two University of Utah researchers that they had discovered how to produce almost limitless energy by running electric current through a bottle of heavy water. After a series of e-mail exchanges, Europhysics Letters published the Argonne response and later declined to publish any more of Collins's papers.

Unable to publish in mainstream journals, Collins had to resort to Laser Physics, a Russian journal of lesser stature. Traditional physics seemed to have won the public battle. Becker's group had produced what it considered to be a textbook experiment that debunked hafnium triggering. The critics thought that, with Argonne's results in print, the 1998 Collins experiment was destined for the scientific dustbin.

Wrong again.

How To Build A Better Bomb

Even as Collins's work was being kicked around by the mainstream scientific community, it was being embraced by the CIA, according to several sources.

Mort Weiss, a retired nuclear physicist who once led Livermore Laboratory's isomer research, recently recalled that a CIA official named Fred Ambrose approached him in the 1980s to discuss CIA concerns about foreign countries developing isomer weapons. Then, after Collins's 1998 experiment, Weiss said, Ambrose became convinced that hafnium could be weaponized and that other countries, primarily Russia, were working actively on such a project. Weiss said he tried to explain that the physics wouldn't work, but Ambrose was convinced it would. "Fred is a true believer," Weiss said.

Ambrose did not respond to a request for an interview, and the CIA declined to comment.

The fears about hafnium technology falling into the wrong hands, and the Pentagon's desire for a weapon that could radiate through hardened bunkers and wipe out biological weapons, could only have multiplied after September 11, 2001. It had been three years since the Jasons' report, and George Ullrich, a senior Pentagon official in charge of weapons research, decided it was an opportune time to reassess the isomer debate. This go-round, the task was assigned to the Institute for Defense Analyses, a federally funded research arm of the Pentagon. Unlike the Jasons, whose 1999 review of the subject lasted just one day, IDA exhaustively researched hundreds of papers on the subject, including those by Collins.

While the IDA report concluded that research on isomers should go forward, it was critical of the focus on weapons. "Don't force it into trying to be practical before the relevant background work is done and it becomes ready for 'prime time,'" the authors wrote. In a personal blow to Collins, the authors also concluded his Physical Review Letters paper was "flawed and should not have passed peer review."

Ullrich's office accepted the judgment and decided that isomers were best left to universities engaged in basic physics research. But soon the nuclear hand grenade would once again explode back from the brink of oblivion.

Martin Stickley arrived at DARPA as a program manager in 2002. Stickley, who had managed research programs for the Air Force in London, had supported research by some of Collins's Eastern bloc colleagues. According to two of the participants in Collins's dental X-ray experiment, Stickley was a believer. The European work, according to McDaniel, "really sparked Martin's interest" in starting a triggering program at DARPA.

Stickley did not respond to requests for comment, and requests to DARPA to interview him were declined.

For Stickley, a promoter of isomer research, the timing was fortunate. The Jasons, who had panned isomer triggering three years earlier, had since been relocated out of DARPA, and it didn't hurt that the 2002 Nuclear Posture Review, unveiled by Secretary of Defense Donald Rumsfeld, emphasized that the United States needed new nuclear as well as non-nuclear bombs to destroy difficult targets, such as buried bunkers that could hide terrorists or weapons of mass destruction.

Last May, Stickley gave a PowerPoint briefing to a review panel in which he promoted the hafnium program as the next revolution in warfare. Hafnium bombs could be loaded in artillery shells, according to a copy of the briefing slides, or they could be used in the Pentagon's missile defense systems to knock incoming ballistic missiles out of the air. He encapsulated his vision of the program in a startling PowerPoint slide: a small hafnium hand grenade with a pullout ring and a caption that read, "Miniature bomb. Explosive yield, 2 KT [kilotons]. Size, 5-inch diameter." That would be an explosion about one-seventh the power of the bomb that obliterated Hiroshima in 1945.

In other words, hafnium, if it worked, would be just what the secretary had ordered.

Under the direction of Stickley, DARPA began to hand out a number of contracts, totaling about $7 million, to national labs and research institutes, most of them associated with participants in the 1998 experiment. According to the Air Force, which administers the contracts, and a DARPA document, McDaniel, Collins and a former student of Collins's, James Carroll, were funded to conduct triggering experiments. The agency planned to spend $10 million in 2004, and then $20 million in 2005, according to a description of the hafnium program that DARPA gave to the State Department.

But Stickley needed to solve a fundamental problem. To make hafnium into a weapon, he would need to produce enough hafnium-178 to conduct a bomb experiment. The micrograms that had been used by Collins and others to test the physics of triggering were nowhere near the amount needed for a bomb. In early 2003, DARPA assembled a 12-member Hafnium Isomer Production Panel (HIPP) to make recommendations on the best way to produce the elusive isomer. Paul Robinson, the head of Sandia, co-chaired the panel along with Ehsan Khan, a Department of Energy official assigned to DARPA's isomer project.

Initial estimates were not encouraging. The Pentagon at first pegged production costs at more than $1 billion a gram, according to Robinson. While McDaniel claims that the production cost estimates have come down by "three orders of magnitude" to about $1 million a gram, the capital costs, according to some members of HIPP, would include $30 billion to $50 billion to build the specialized facilities needed to produce hafnium.

But as it turned out, production was only one of HIPP's concerns.

Among the experts appointed to the panel was Bill Herrmannsfeldt, who had worked for 40 years at the Stanford Linear Accelerator Center. Herrmannsfeldt, by his account, began his research by typing the word "hafnium" into the Google search engine. One of the hits concerned the Argonne experiment, which led him to the Jasons' study, and then the IDA study, all questioning the original Collins experiment. He saw the ominous shadow of cold fusion creeping in through the crack of a Pentagon door. It was all there for him: the incredible claims, the immediate doubt and, most important, the inability of independent researchers to successfully repeat the original experiment.

His doubts became stronger when HIPP members met to discuss the production issues. Collins made a presentation to the panel, criticizing the Argonne experiment, and yet no members of that experiment had been invited to the meeting. Herrmannsfeldt said he tried to discuss his doubts about the science with Stickley and Khan, but to little avail. "I begged Khan to invite the critics, maybe I even threatened him, because this was really dangerous, even worse than I thought it would be," he said.

Frustrated by the lack of response from DARPA, Herr-mannsfeldt spearheaded a campaign to undermine the very project he was supposed to help move forward. His anger peaked with an August 13, 2003, letter written directly to Stickley at DARPA and Khan at the Department of Energy. Signed by five members of the HIPP panel and 10 experts in the field, Herrmannsfeldt's letter urged another review of hafnium triggering.

In Washington this January for another HIPP meeting, Herrmannsfeldt spoke calmly and softly about his concerns. He jotted down equations to show how DARPA would never get any useful energy out of hafnium. He talked about the reviews and competing experiments. He acknowledged his political concerns about the program -- he calls hafnium "the mother of all dirty bombs" that would entice other countries to build nuclear weapons -- but he based his argument on science. "I complained about the lack of respect for scientific advice, major reviews such as the Jasons and IDA," he said after the latest meeting. "Martin [Stickley] then came back and not very politely told me DARPA was above such things, and 'could ignore any publicity' around the program."

The end result of the panel's meeting, according to Herrmannsfeldt, was that Khan and Stickley were enthusiastic that production costs could be brought down. The program would go on.

'High Risk, High Payoff'

In the early spring of 2002, DARPA's annual tech expo was held in Anaheim, Calif., at Disneyland. In his keynote speech, DARPA Director Anthony Tether explained, "I thought there was nothing more appropriate than having DARPATech at Disneyland. Disneyland is a land of dreams and fantasy becoming reality, and that is what DARPA does and does well."

In its 46-year history, DARPA has had some incredible successes -- such as ARPANET, now better known as the Internet. It also has had plenty of failures.

But, Tether reminded his audience, "there is no sin in failing at DARPA. "Why?" he asked. "Because no one remembers the failure."

"High risk, high payoff" is Tether's motto, and it is DARPA's job to fund far-out ideas. Put in that perspective, the $7 million DARPA spent on isomer research last year is barely a drop in an annual defense budget of more than $400 billion. So why worry?

"I think the critics recognize that by Department of Defense standards, it's not a lot of money," said Ivan Oelrich, a former IDA scientist now at the Federation of American Scientists. "Even if they think it's a total waste, why lose sleep over it? The Defense Department spends about $16,000 a second, so by DOD standards, it's not much to worry about. That might be part of the explanation."

But Oelrich, who is familiar with isomer research from his days at IDA, argued that money alone should not be the standard for judging the program. Though DARPA reasonably wants to err on the side of pushing things too hard, rather than being too conservative, he explained, "there have to be some standards." Triggering hafnium, in his opinion, just didn't meet any intelligent standard.

Even one of the beneficiaries of DARPA's spending on isomer research, James Carroll, Collins's former student, has some concerns about the agency's approach. From his office in Youngstown, Ohio, Carroll argued that isomer triggering is not analogous to cold fusion, but he also described his unease with the focus on weapons. DARPA's involvement in isomer research is similar to an "impedance mismatch," he said, a scientific term describing the result of joining two systems that have different conceptual bases. DARPA wants a fast track, Carroll explained, but isomer research is still at the very basic stage. "It's a mismatch between expectations and reality. That perhaps is the difficult part here."

Isomer research is extremely good basic science, he said. "Maybe you can never make anything practical out of it . . . Maybe none of it will pan out. But in the meantime, we will learn a lot about how the nucleus responds to people banging on it."

In declining to answer specific questions about DARPA's work on hafnium, Tether responded with a general written statement offering a compelling argument for pursuing the hafnium bomb. The countries of the former Soviet Union are interested in isomer weapons, he said, and "an enemy with this capability could create havoc on a scale that has never been seen before." He raised the specter of isomer car bombs and "a suicide bomber with a few pounds of isomer."

While such weapons could be devastating in the hands of an adversary, it would be useful for the United States to have it as a deterrent, Tether wrote. An isomer bomb "would give the U.S. a capability that would truly be revolutionary given our ability to deliver small munitions with incredible precision."

Isomers Hit Prime Time

The Capital Beltway is a world away from Collins's lab. Unlike the sparse landscape of the University of Texas at Dallas campus in suburban Richardson, Tex., Northern Virginia is dotted with hotels where defense contractors, scientists, researchers and "Beltway bandits" come to visit with their Washington sponsors. Common perception holds that the Pentagon itself houses the Defense Department, but in reality its offices extend along the Metro's Blue Line, from Rosslyn, where acquisition managers line Wilson Boulevard, to Crystal City, where satellite offices handle everything from foreign military sales to the management of a $200 billion fighter aircraft program.

Visiting defense contractors meet in conferences, on panels and at seminars in the Sheratons, Hiltons and Marriotts that populate Northern Virginia. While rarely five-star accommodations, they are all a convenient 10-minute drive to the Pentagon. The Hilton Towers in Ballston is definitely not for the high-end bandit. Sandwiched between a Metro station and an office building, the lobby of the hotel is the size of a typical family dining room, and the industrial carpet shows the wear of daily visitors rushing to early-morning appointments.

Sitting in the lobby one day last fall, an Army captain read the sports page, with a PowerPoint briefing at his side marked "Transformation, Now!" -- the Pentagon buzzword of the day. Rising from the opposite couch, a woman enthusiastically greeted a Russian doctor. They were off to a biological and chemical defense meeting. And here, too, was Carl Collins, all smiles and dressed as you might imagine any professor, with a golf shirt and sports jacket. Collins was in the area to brief DARPA's higher-ups on the progress in hafnium triggering, yet he seemed somehow out of place.

Defense contractors call the Pentagon "the customer," and speak about program "milestones," mixing military metaphors with business euphemisms and indecipherable acronyms. Collins does not walk the walk or talk the talk of a defense contractor. He speaks about the scientific method. He says he has never had a security clearance, and doesn't want one. He prefers doing research out in the open and wants to continue working with colleagues from behind the former Iron Curtain, he says. Although not particularly bothered by the military applications that have caught the eye of DARPA, he seems genuinely uninterested in its focus on weapons. He says that he really wasn't aware of how or why the agency became involved in his research. He had a contract in place with the Air Force, and at some point he simply noticed that part of the money was coming from DARPA.

In fact, that fall day in Ballston, Collins said he was unsure that hafnium would be useful for a bomb, though he claimed not to have given it much thought. If he had given any thought to applications, he said, it was to the concept of using tiny amounts of hafnium "seeds" for cancer therapy. The isomer seed, Collins said, could be "triggered" to give out precisely the right amount of gamma rays needed to destroy a tumor. There was already some interest in this from the Mayo Clinic, he said.

Collins laughed at the mention of the infamous dental X-ray machine. "That's not the worst of it," he said. "Sometimes we used car parts." But the truth is, he said, there is nothing wrong with using a dental X-ray machine to save money. And more importantly, he said, in 2001 he and his team, working with Japanese colleagues, went on to validate his original results at the world's most advanced X-ray source, the Spring-8 facility near Osaka, Japan. Collins chose Spring-8 precisely because he needed an advanced synchrotron, which can be tuned to precise energy levels. In his mind, this was the scientific method at work, the reproduction of earlier results proving out his theory of isomer triggering.

Collins is not beyond a bit of drama: He sees himself and his challenge to traditional nuclear physics as the modern-day equivalent of the trials of Giordano Bruno, the Dominican monk who was burned to death in 1600 for claiming Earth revolved around the sun. The "expert panels" represented by the Jasons and other critics are trying the same scare tactics, according to Collins. "You start talking about expert panels, that's exactly what they did to Bruno," Collins said. "This is the same thing."

But despite Collins's view that his initial triggering results were validated at Spring-8, there has been a lot of bad news since the big flash of attention in 1998. First, James Carroll, his former student, broke with Collins's group shortly after the first experiment and went on to set up his own gamma-ray research team at Youngstown State University, taking with him prominent Russian scientist Sarkis Karamian. Worse for Collins, Carroll began to challenge Collins's contention that the 1998 experiment -- and later experiments -- was clear proof of triggering. The data were not conclusive that triggering took place, Carroll maintained, saying that the results were "intriguing" but very preliminary. Carroll and Collins both declined to speak about the break, other than to acknowledge that it has personal as well as professional dimensions.

Collins asserts that his critics don't accept his results only because they didn't come out of a large science center. The mainstream journals are dominated by a "daisy chain" of famous scientists unwilling to accept groundbreaking work from outside their clique, he contends. Yet, at the same time, he denies that mainstream physicists reject his work, and points to allies like McDaniel.

McDaniel, who now works at Sandia, is a crucial part of the isomer debate because, while a Collins collaborator, he is also the only person who claims to have independently reproduced Collins's results. Using DARPA's sponsorship, McDaniel and his colleagues conducted a series of separate experiments, including three at a high-tech X-ray source at Louisiana State University over the past year. According to McDaniel, one experiment "seemed to corroborate Carl's results very well" and with fewer errors than previous Collins work. Another experiment proved difficult to measure, he said. A third experiment has been conducted, but he hasn't yet had time to assess the data.

McDaniel, however, has never published any of those results, giving rise to criticism that his alleged confirmation is meaningless. "All the data's noisy, so we were reluctant to publish," McDaniel said of his most recent experiments. Besides, he added, "publish or perish is not a problem for government employees."

The "noisy data" that concerned McDaniel involves statistical uncertainty and, possibly, background radiation that makes it difficult to be sure the instruments are measuring emissions from the hafnium, and not from something else. Another problem is the chronic inconsistency in experimental results. Some of McDaniel's tests produced data that exceeded the 1998 results, but others failed to show anything. It is hard to explain these differences, McDaniel acknowledges, but he argues the inconsistencies are reason enough to continue the experiments.

McDaniel contends that much of the criticism of hafnium is based on political concerns over a weapon. If hafnium proves out its potential, then the government will face a political decision. "If it does work, it's the same question about the super," McDaniel said, referring to the 1950s debate over developing the hydrogen bomb. The critics are trying to fight the science in the press because they don't like the politics, he said. "The issue is, in a free society, we need to know what's possible."

McDaniel, for one, believes that hafnium triggering is possible, and at Sandia last year, Paul Robinson, the head of the laboratory, was beginning to believe it, too. As a graduate student back in the '60s, Robinson himself had been interested in building a gamma-ray laser, and as an experimental physicist, he liked the romantic notion of proving the theoreticians wrong. More importantly, he trusted the work of Pat McDaniel. So, why is definitive, bowl-over-the-critics proof in such short supply? This is often the way new science discoveries start out, Robinson suggested.

"I suspect you'll keep looking at the triggering until you get it firmly established that you can do it," he said last year.

Of course, by that point, he noted, hafnium research "would probably be made classified, and you wouldn't read about it."

Robinson's remarks proved prescient. Last November, DARPA's talk of a new weapon made its way to the State Department's Bureau of Nonproliferation, which wanted to know why everyone was discussing plans for a new super-bomb out in the open. The bureau sent a batch of e-mails to government scientists expressing concern that without more secrecy, isomer technology could fall into the hands of terrorists or rogue states.

Scientists who had been involved in the work at Argonne were apoplectic. The idea that the government would make a nonexistent weapon a classified secret struck them as silly, and also as dangerous if it meant that the scientific debate became shrouded in secrecy. As Don Gemmell, the Argonne physicist, responded in frustration, "Classifying the work at this stage would serve to protect this waste from public scrutiny. I would sooner see us look for ways to trigger a chain reaction in sugar. The material is readily available, is not radioactive, has an energy density greater than TNT, and is about as likely to work as 178Hf!"

At least some of the scientists' doubts may have reached DARPA. According to Herrmannsfeldt, the critic on the production panel, in late February two leading weapons scientists, both critical of the isomer program, jointly called Tether. After the conversation, DARPA's director took one step back. Rather than putting money into hafnium production immediately, according to DARPA spokeswoman Jan Walker, the agency will focus on experiments to "scientifically prove, to the satisfaction of the majority of the nuclear physics community," that isomer triggering is real. For now, rather than the $30 million originally planned for 2004 and 2005, DARPA will spend just $7 million, according to updated budget submissions.

Zimmerman, the former arms control agency chief scientist, is skeptical that even the more cautious approach will make much difference in the end. "I think that a program like this, once started, will have an enormous amount of inertia," he said. It won't be a matter of someone deciding that this is just a waste of money, it will stick around for years, and likely grow in scope, he added. Zimmerman's concerns also go well beyond the science. "Are we going to advertise that we are going to build a new nuclear-type weapon based on new physical principles?" he asked.

The isomer bomb is foolish, Zimmerman said, but it's foolish in a dangerous sort of way if it pushes other countries to build real nuclear weapons in the hope of deterring the United States from using a fanciful hafnium bomb.

Back at Carl Collins's office in Texas, a clutter of paper shrouds his desk. A portrait of a beautiful young woman -- an old photo of Collins's wife, Doina -- stands out amid the chaos. Nearby is a copy of a novel by Dallas author Payne Harrison, who has written a number of techno- thrillers. The plot of one of them, Thunder of Erebus, has it all: a fictional isomer called rubidium-86, gamma-ray lasers for Star Wars, and then DARPA's development of a new, super-conventional weapon based on isomer triggering after Star Wars is canceled. In the book, Russia decides that it must control the world's supply of rubidium-86 (which, in the novel, is in Antarctica) for fear of DARPA's secret isomer program. Ironically, the Pentagon fears the Russians will build their own isomer weapon and then invade a country in the Persian Gulf.

Some years ago, Harrison hung around the gamma-ray lab for a few months "to absorb the culture," according to Collins. The author, a former tax accountant, shadowed Collins's team, eventually drifting out of the lab as quietly as he came in.

The odd thing is, Thunder of Erebus was published in 1991 -- a full decade before DARPA says it ever funded work on an isomer bomb.

Last May, Collins appeared at a DARPA meeting and showed a slide of a man hitting a golf ball across a field, a mushroom cloud rising at the end of the ball's arc. The caption read: "A golf ball filled with the isomer would have the energy of 10 tons of explosive." Collins was visibly uncomfortable when asked about the diagram, which was displayed at a closed meeting, and said apologetically that the "sponsors," DARPA, had asked him to make an illustration to show hafnium's potential. Collins is an avid golfer.

Asked how he felt about conducting an experiment whose results, if true, could lead to the next super-bomb, Collins began to talk about the need for science in a free society, about the medical applications, and then paused. "I guess I don't feel anything. At some point, I'll retire and go play golf," he said with a smile.

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