“No, I don’t,” he grumbled as he immediately tossed the cigarette and got out.
He looked around, and the sight of him hitching up his pants and inspecting his car because he could not help himself was too much. Lucy and I both laughed, and then he tried not to smile. In truth, he secretly enjoyed it when we teased. We bantered a little bit more, and then Lucy left as a late-model gold Lexus with tinted glass drove past. It was the same one we had seen earlier on the road, the driver obliterated by glare.
“This is beginning to get on my nerves.” Marino’s eyes followed the car.
“Maybe you should run the plate number,” I stated the obvious.
“Oh, I already done that.” He started the car and began backing out. -DMV’s down.”
DMV was the Department of Motor Vehicles computer, and it was down a lot, it seemed. We headed back up to the reactor facility, and when we got there, Marino again refused to go inside. So I left him in the parking lot, and this time the young man in the control room behind glass told me I could enter unescorted.
“He’s down in the basement,” he said with eyes on his computer screen.
I found Matthews in the low background counting room again, sitting before a computer screen displaying a spectrum in black and white.
“Oh, hello,” he said, when he realized I was beside him.
“Looks like you’ve had some luck,” I said. “Although I’m not sure what I’m seeing. And I might be too early.”
“No, no, you’re not too early. These vertical lines here indicate the energies of the significant gamma rays detected. One line equals one energy. But most of the lines we’re seeing here are for background radiation.” He showed me on the screen. “You know, even the lead bricks don’t get rid of all of that.”
I sat next to him.
“I guess what I’m trying to show you, Dr. Scarpetta, is that the sample you brought in isn’t giving off high-energy gamma rays when it decays. If you look here on this energy spectrum–he was staring at the screen–it looks like this characteristic gamma ray on the spectrum is for uranium two-thirty-five.” He tapped a spike on the glass.
“Okay,” I said. “And what does that mean?”
“That’s the good stuff.” He looked over at me.
“Such as is used in nuclear reactors,” I said.
“Exactly. That’s what we use to make fuel pellets or rods. But as you probably know, only point three percent of uranium is two-thirty-five. The rest is depleted.”
“Right. The rest is uranium two-thirty-eight,” I said.
“And that’s what we’ve got here.”
“If it isn’t giving off high-energy gamma rays,” I said.
How can you tell that from this energy spectrum?”
“Because what the germanium crystal is detecting is uranium two-thirty-five. And since the percentage of it is so low, this indicates that the sample we’re dealing with must be depleted uranium.”
“It couldn’t be spent fuel from a reactor,” I thought out loud.
“No, it couldn’t,” he said. “There’s no fission material mixed in with your sample. No strontium, cesium, iodine, barium. You would have already seen those with SEM.”
“No isotopes like that came up,” I agreed. “Only uranium and other nonessential elements that you might expect with soil tracked in on the bottom of someone’s shoes.”
I looked at peaks and valleys of what could have been a scary cardiogram while Matthews made notes.
“Would you like printouts of all of this?” he asked.
“Please. What is depleted uranium used for?”
“Generally, it’s worthless.” He hit several keys.
“if it didn’t come from a nuclear power plant, then from where?”
“Most likely a facility that does isotopic separation.”
“Such as Oak Ridge, Tennessee,” I suggested.
“Well, they don’t do that anymore. But they certainly did for decades, and they must have warehouses of uranium metal. Now there also are plants in Portsmouth, Ohio, and Paducah, Kentucky.”
“Dr. Matthews,” I said. “It appears someone had depleted uranium metal on the bottom of his shoes and tracked it into a car. Can you give me any logical explanation as to how or why?”