Richard Castle - Wild Storm

“Okay, Alida,” Storm said, smiling. “Let’s start with: why promethium?”

For the first time since they met, Alida smiled. “Do you like science fiction, Mr. Storm?”

“What red-blooded American boy raised on Ray Bradbury and Rod Serling doesn’t?”

“In that case, I think you and Billy are kindred spirits. One of the reasons he wanted to pursue it was simply for the name. I mean, a promethium laser beam. It just sounds cool.”

“It does.”

“But there’s also a scientific utility to it as well. How much do you know about solid-state lasers?”

“Perhaps I should have also mentioned Star Trek creator Gene Roddenberry? But that’s about as far as it goes.”

She smiled again. “Okay. I’ll give you the non–science fiction primer. I’ll try not to bore you with the details, but one of the big distinctions in the laser world is three-stage versus four-stage. There are only a small handful of elements that make four-stage lasers.”

“What’s the difference?”

“Four-stage is a hundred times more powerful than three-stage.”

“Big difference,” Storm said.

“Probably ninety percent of the solid-state lasers out there are made with neodymium, which happens to be next to promethium on the periodic table. They’re both elements that are known as lanthanides, which are…I’m losing you, aren’t I?”

“A little. I slept a lot in Mr. Menousek’s chemistry class, which I regret. Most of the chemistry I know about deals with how to make and defuse bombs.”

She let that pass without comment. “Lanthanides are better known as rare earth metals. They have all kinds of practical uses, especially in high-tech gadgetry. They’re mined all over the world, from Sweden to South Africa to Australia to China. Anyhow, where was I?”

“Neodymium.”

“Right. Most of the lasers are made with neodymium. But Bill had always had his eye on promethium. Every element has a different wavelength when you make a laser out of it. Remember ROY G BIV from science class? That’s the color spectrum as it appears in nature. The lower wavelengths are red. The higher wavelengths are violet. Still with me?”

“Definitely.”

“Okay, so promethium checks in at nine-hundred-thirty-three nanometers, which is not in the visible spectrum. But when you put a cesium filter on it, it radiates at four-hundred-fifty-nine nanometers, which is a very pure blue, the best blue you can get from a four-stage element.”

“Are you sure you weren’t the lead researcher on that paper?” Storm teased. “Your recall of those numbers is amazing.”

“Have you ever published a scientific paper? You end up writing it and rewriting it and editing it so many times to please some idiotic review committee, you feel like you have the thing memorized by the end. Anyhow, four-hundred-fifty-nine nanometers is significant, because it turns out to be the perfect wavelength for slicing through the Earth’s atmosphere, which is also very blue in the middle of the day. There’s almost no loss of power.”

“So if you were designing a high-energy laser beam that you wanted to use to, say, shoot down airplanes, this would be the stuff?”

“Bill always said that a high-energy promethium laser beam would be an incredible weapon,” she confirmed.

Storm tapped his finger on the countertop. Sometimes he hated being right. She poured him an iced tea refill from a glass pitcher lightly beaded with sweat. Storm started posing his next question as she topped off his glass.

“Well, now, let me ask you this: if promethium is such dynamite stuff, why didn’t he do more with it while he was at Lawrence Livermore? Why wasn’t he trying to develop this for the military? Why wait until he retired?”

“Oh. Right. Promethium was…it was more of a hobby for Bill, I guess. For one thing, it’s mildly radioactive, so it’s a little difficult to deal with. It’s easy enough to shield, so it’s not like I worried much about it. They actually used promethium to power the batteries in some of the first pacemakers. But when lithium batteries came along, they were a lot lighter and smaller, so out goes promethium. But the biggest reason promethium had limitations was, well, remember how I mentioned promethium is a rare earth?”

“Yes.”

“It’s probably the rarest of the rare earths. Bill said there was no more than twelve pounds of the stuff spread out over the entire Earth’s crust. No one has ever found a large deposit of promethium. Bill worked with very small amounts of it. I saw it when they shipped it to him, before he put it in crystal form. It was just this white powder in this little clear plastic bag, almost like it was a drug or something. Except it wasn’t as fine. It was more granular.”

“And someone had, what, found it in a mine somewhere?”

“Oh, no. It had been fabricated in a nuclear reactor. Promethium isn’t found naturally. At least that’s what Bill said. That’s why all this stuff you’re saying about a high-energy promethium laser is a little out there. High-energy laser beams require very large crystals — the larger the crystal, the more powerful the laser. Billy was the one who did the math, so I couldn’t give you the exact number. But I do know you would need several hundred pounds of promethium to make a crystal big enough for a high-energy laser capable of doing the kind of damage you’ve described.”

Storm looked at his iced tea, studying a lemon seed floating within the light brown liquid.

“Could someone with access to a nuclear reactor fabricate that much promethium?” he asked.

“I don’t think so. You make it by splitting plutonium atoms, and it’s not like that’s easy to come by. It’s also a pretty slow process. The promethium Bill used came from the Oak Ridge Laboratory in Tennessee. Even at their peak, when they were making promethium for those batteries, they didn’t make more than about fifteen pounds a year. By the time you made a few hundred pounds’ worth, the older stuff would have decayed. Even the most stable promethium has a half-life of less than three years.”

“So how would someone get enough promethium to do this?”

Alida shook her head. “I don’t know. The only good news is that whatever supply they have will only last so long. As the promethium degrades, it causes impurities in the crystal. The one Bill made for that paper he wrote eventually stopped working.”

“How long did that take?”

“A few months.”

“Meaning whoever has this weapon will be able to keep using it with impunity for the immediate future?”

“I’m afraid so.”

“It would stop working after a few months. But then, if they had more promethium, they could make another weapon.”

“That’s right.”

Storm took a sip from his tea. “In the most perverse way, that’s good news for you.”

“How so?”

“Because it means whoever has grabbed your husband will have to keep him alive. And if he’s alive, I’ll find him.”

“You…you will? In your capacity as…a contractor for the government?”

“No. In my capacity as a human being.”

Alida did not reply. She had placed a hand over her mouth. Storm noticed tears were pooling in the corners of her eyes.

JUST DOWN THE STREET, behind a partially drawn curtain, in an empty house with a FOR SALE sign out front, a man spoke into a Bluetooth device that was planted in his ear.

“Yeah, he’s still there,” he said in an accent that came from somewhere south of the Mason-Dixon Line.

The man had short-cropped hair, a nose that had been broken several times, and a jaw that was twice the size it needed to be. A loaded Bushmaster Carbon-15 with a Trijicon ACOG 4X32 scope leaned against the wall next to him. He wore a Colt .45 in a shoulder holster. And he kept a Buck knife in an ankle sheath.