"On the other hand," Sharp continued, "the gamma-ray laser, or Graser, presented a very attractive alternative of unbelievable potential. That's because the Graser device causes the nucleus, not the electrons, of the atom to oscillate and generate the energy pulse. If you gentlemen recall your basic college physics course, you know that a proton or neutron in the nucleus of an atom has over eighteen hundred times the mass of an electron. Suppose, for example, an electron had the mass of a baseball. If your son threw that baseball at your neighbor's home, it would break a window. If he threw the equivalent weight of one proton, it would be like throwing the family car, and it would probably level the house. That gives you an idea of the difference in scale between the raw material of a laser and that of a Graser. It does not, however, give you an indication of the scale of the energy released."
Sharp paused and took a sip of water. "With the Graser, the nuclei of a rubidium isotope are stimulated by X rays. These nuclei then oscillate into a 'lase' pulse, and the funneled energy is released in the form of gamma rays. The wavelength of these gamma rays is incredibly short — less than an angstrom — and they are released in an energy beam approximately four kilometers wide. This beam width is amply wide enough for targeting purposes. Indeed, it can strike down several missiles or warheads in a single pulse. And the power requirements to operate the device are minor, relative to the laser."
Sharp paused again to collect his thoughts, then continued, "The final issue I wish to point out is that the energy released in the Graser pulse is approximately twenty trillion watts. Quite enough to obliterate any missile."
Again, the Treasury Secretary broke in. "Did you say twenty trillion watts?"
"Yes, sir," replied Sharp.
The Secretary's walruslike mustache twitched as he puffed on his cigar and mentally tried to get a handle on the number. "That sounds like a lot," he said finally.
"Yes, sir. To give you some idea, the power output of all electric power plants worldwide, nuclear and conventional, is about two point three trillion watts."
It took a few seconds for the numbers to sink in on the Secretary. When they ultimately registered he exclaimed, "Good God!"
The President bored in on his new money man. "You keep your mouth shut about what you hear in here, Milton. Understand?"
The Secretary gulped. "Yes, yes, of course, Mr. President. But, my God, the power. I had no idea. How on earth does this contraption work?"
Sharp didn't flicker. He might have been describing how an electric train worked. "Conceptually the process is surprisingly simple. As I said, the nuclei of a rubidium isotope are stimulated by X rays, then 'lase' into a pulse at the isotope's own wavelength and are released in the form of focused gamma rays, which are out of the visible light spectrum. I know, Mr. Secretary, that the amount of energy we're talking about is beyond comprehension, but that is the kind of power locked inside the atom. Nuclear fission, even fusion, is relatively inefficient compared to the Graser. In fact, when we make comparisons to fusion energy in our lab work we have to use a logarithmic scale. However, you have to keep in mind we're talking about a nanosecond pulse, not a constant. Even so, the scale is overwhelming. For example, if I had a glass" — Sharp held up his drinking glass—"full of the rubidium isotope, the power output generated by a gamma-ray laser pulse could be equal to a hundredth of one percent of the energy of the sun."
The Secretary's hands were shaking. "A glassful7"
"Yes, Mr. Secretary."
"That means if you had a… a swimming pool full of this, this iso-whatever-you-call-it, you could generate the power of the sunT'
Sharp looked at the ceiling, running through some equations in his head. "No. I don't think you would need an entire swimming pool."
The Secretary's mustache was quivering now as he nervously fingered his gold watch chain. "How much of this ruby stuff does it take to make this Graser space gizmo work?"
"Approximately half a thimbleful," Sharp relied flatly.
"Haifa thimbleful?" The money man felt weak. He longed for the frenetic stock-trading floor at his old firm. It seemed a much safer place to be right now.
"Yes, Mr. Secretary," explained Sharp. "And that was the major problem in developing the Graser. You see, fourteen common chemical elements make up ninety-nine percent of the earth's mass, and the bulk of the one thousand, eight hundred and eighty-seven isotopes that exist come from the remaining one percent of the earth's matter. The biggest hurdle in developing the Graser was finding the right isotope with a natural wavelength that could be used for funneling the stimulated nuclei. I mean, laboratories all over the world searched for years trying to find the right isomer substance for the Graser. It was a difficult process, but we found that an extremely rare isotope of rubidium worked best. "
"What the hell is that? I never heard of it before," complained the old financier.
"Rubidium. I guess I should point out that it is not to be confused with ruby crystals, which are commonly used in lasers," explained Sharp. "It just has a similar name. Rubidium is the sixteenth most common element found on earth. It's a soft, silvery-white metal, and for many years it was thought to possess only seventeen isomer forms… An isotope, by the way, has the same chemical properties as a given element, but possesses a different atomic structure.
"Anyway, a few years ago the National Laboratory at Oak Ridge, Tbnnessee, discovered that there was an eighteenth isotope to rubidium, and much to our surprise at Livermore, we found it had excellent qualities for the Graser. This isotope was rubidium-98, or Rb-98, for short. Unfortunately, however, rubidium-98 is an extremely rare isotope. It is radioactive and has a half-life of approximately fourteen months. We obtained it through a long and arduous laser diffusion process at Oak Ridge, and it took us eleven months just to produce that half thimbleful. With a half-life of fourteen months, you can understand the production problem."
The Secretary was still aghast. "I just can't believe it. You produce twenty trillion watts with a half thimbleful of this ruby stuff?"
"Yes, Mr. Secretary," responded Sharp without emotion.
In a gesture he had not made since he was an altar boy, the Secretary made the Sign of the Cross, and he didn't care who saw it. "With something like this, you could wipe out an entire city with a single blast, couldn't you?"
Sharp shook his head. "No, sir. The Graser only works in a vacuum. The gamma rays rapidly disperse when they hit the atmosphere. It can only be used against missiles when they are in the exoatmospheric phase — or, in simpler terms, when they are in the vacuum of space."
The Secretary sagged with relief. "Thank God for that." Compared to the Graser, a little thermonuclear warhead seemed like a toy.
The President was rubbing his temples. "I have to ask you, Dr. Sharp. What part of the Graser system was aboard the Intrepid!"
Sharp took off his glasses. "As you know, Mr. President, we designed the Graser in components so it could be easily installed and deployed on the platform. The structure of the device is like a hub and spokes. The Rb-98 isotope is housed in the hub, and the X-ray channel rods of the SDI platform are arranged around the hub like the spokes of a bicycle wheel. The six channel rods feed their X rays into the isotope, then the gamma rays are pulsed out from the hub."