The Zero Hour (50 page)

Simply put, they did not know whether the bomb was set to detonate if anyone came near it. The fusing mechanism had been intensively examined in a Department of Energy laboratory to determine how much energy it would take to set off the detector, whether there was a sensitivity switch or a variable resistor. Dr. Payne had himself plotted the RF (radio frequency) emanation relative to the position of gain control. He knew how much motion would set the thing off. He knew that it was designed not to respond to motion beyond twenty-five feet.

But he didn’t know whether the sensor had been dialed up, extending the safe line to forty or fifty feet or more. And it was possible the sensor wasn’t even on.

He had no idea.

This much he knew for sure: his men had not set off the bomb. Wherever the safe line was, they hadn’t stepped over it.

But it might be located at the doorjamb, and they would have to assume that it was.

If there was indeed a proximity detector in force, Payne thought, most likely it affected the area on the other side of the door. Microwaves, for all practical purposes, do not go through steel.

But to be safe, they could not risk encroaching even an inch beyond where the closest man—Dr. Payne—was standing. All of their tests had to be conducted from their present positions, and no closer.

The first order of business for the team was to rule out the presence of a nuclear weapon. To do that, they had to test for radioactivity. Not knowing what was in the nuke, or even if it was a nuke at all, they had no way of knowing whether to test for alpha or beta particles, or gamma waves, or for neutron emission. Each is detected by means of a separate procedure. They could test either for whatever radioactive substance was in the bomb or for the “degradation material,” the substance the bomb material would degrade into.

Dr. Payne knew they were not close enough to test for alpha or beta emissions. That left neutrons and gamma. If their detectors “smelled” a large quantity of gamma waves and a small quantity of neutrons, they were probably dealing with uranium; if they “smelled” the opposite, it was probably plutonium.

Their tests told them that the bomb inside the steel door was not nuclear.

That was a relief, though it lasted only a few seconds.

*   *   *

In a darkened room on the building’s fifth floor, Baumann was working with a soldering iron and a pair of wire cutters. Jared, his arms and legs bound, wriggled on the floor a few feet away, thumping his duct-taped feet against the floor in an ineffectual attempt to summon someone, anyone. But the floor was tile over concrete, and the thumping made barely a sound, and in any case, the top floors of the building were by now evacuated. There was no one on the floor to hear him.

Baumann continued to work, his concentration undisturbed.

CHAPTER NINETY-FOUR

The next order of business for the NEST men was to determine whether the microwave detector had indeed been turned on. If not, they could force open the steel door and safely approach the bomb to render it safe.

If it was …

Well, the first thing was to determine whether it was on or not. To do that, they used a device known as a microwave sniffer, which looks for emanations in the microwave wavelength, above ten gigahertz. A version of this same device is used to test kitchen microwave ovens for leaks.

A junior member of the team, an Army sergeant named Grant who was trained in explosives detection, took the microwave sniffer’s long, flexible antenna and pointed it at the steel door as Payne directed him to do.

“Dr. Payne,” he said, “we’re just not going to get anything. This door here is steel, and microwaves are pretty much blocked by steel, sir. It’s going to mask the microwave emanations.”

“That’s right,” Payne said. “But keep at it, please.”

Sergeant Grant had served in the Army long enough to know how to take orders with grace, so he continued, though with a trace of reluctance. The microwave sniffer was silent.

“You want me to sort of snake this antenna under the door?”

“
No
, Grant. That’s a huge risk. Bad idea.”

“Sir,” Grant said, “Like I said, this here door—” But he was interrupted by a rapid, high-pitched beeping. The sniffer had gone into alarm mode.

The antenna, which Grant had pointed at the crack between the bottom of the steel door and the concrete floor, was being bombarded by microwaves exceeding its preset threshold.

“Oh, shit—” Grant cried out.

The microwave detector was not just in force on the other side of the door. Microwaves were leaking under the door. If anyone moved even a few inches closer to the door, there was a risk the bomb would be set off.

“Freeze!” Payne shouted. “
Everybody freeze!
”

The beeping continued.

“All right,” Dr. Payne said in a quiet, steady voice. “The thing hasn’t exploded. That tells us something. But any further motion might set it off.”

“Jesus!” Grant whined. He was frozen in an awkward position, partially bent toward the floor, his extended right hand gripping the microwave sniffer’s antenna. It was pointed at the gap between floor and door, which was no bigger than a quarter of an inch. The antenna was approximately six inches from the floor. He shifted slightly.

“Don’t move a fucking
muscle
,” Payne hissed. “We’re picking up the microwaves that are coming through from under the door. The door is sealed tight against the doorframe everywhere except against the floor.”

“I can’t stay this way,” Sergeant Grant moaned.

“Goddammit,” Payne said, “don’t move a muscle or you might just kill us all.” He felt his body flood with panic.

Grant’s eyes widened. Except for the rapid beeping, the entire stairwell was silent. Thirty men were standing almost completely still. From a distance there were faint shouts, distant sirens; but here the only sound was the papery whisk of their windbreakers as the men shifted stance ever so slightly, and the mechanical beeping.

“Now, listen,” Payne said. “Everyone, look down at your feet.”

Obediently, everyone on the team did.

“Memorize that position. Keep your feet in
exactly
that position. Even a reflection of a body might be picked up through that gap. I don’t know why we haven’t set it off yet—maybe the sensor just switched on. But if you move your feet, you may cause it to detonate.”

“Oh, please, God,” someone said.

“If you have to move, move parallel to the door. You’re less likely to set it off that way. But if I were you, I wouldn’t move a fucking muscle.”

“I—can’t—” Grant gasped. A tiny, liquid noise came from near the sergeant’s feet, which Payne quickly realized was a trickle of urine. A long stain darkened his left pant leg. Payne, though as frightened as any man here, felt acutely embarrassed for Grant. No doubt Grant knew that this would be his last assignment with NEST.

Yet Payne could not help thinking, morbidly, that this might be his own last assignment as well.

One of the men—the one who had just said, “Oh, please, God”—was, in shrink jargon, decompensating. He was a scientist from DOE headquarters, a young man, in his early thirties, and he had begun to babble.

Payne ignored him, praying only that the young man wouldn’t move. If he did, at least he was one of the farthest from the door. Although he had broken out in a cold sweat, he knew he could not afford to divert his attention to this man, or to Sergeant Grant, who, despite his accident, at least had the self-control to remain frozen in position. Important decisions had to be made.

There is a concept you often hear among bomb-squad technicians: the bomb’s
wa
. A bomb’s
wa
is its overall state of being.

In order not to disturb a bomb’s
wa
, you have to understand and appreciate its
wa
, and Payne had not yet done that. He only knew that opening the steel door would likely disturb the
wa
.

Payne could feel his anal sphincter squeeze tight as his body grew increasingly tense. This was a phenomenon well known to bomb techs—“asshole-puckering,” they called it. The detector was beeping furiously, telling them that the wrong move would detonate the bomb. Yet you couldn’t see anything, couldn’t smell anything. What did the beep signify? How sensitive was the microwave field?

“Grant,” he said gently, “can you listen to me?”

“Sir,” Grant croaked.

“Grant, I want you to move that antenna upward by a few inches. Do you understand me? Slowly and steadily. Upward.”

“Yes, sir,” Grant said. With a trembling hand he inched the antenna up. As he did, it shook up and down.

“Steady, Grant.”

“Doing my best, sir.”

The beeping stopped.

Sergeant Grant had moved the antenna less than six inches up from the floor, and apparently it was now out of range of the microwave sensor. “That’s the safe line,” Payne whispered, more to himself than to the others. “The microwaves are not moving through the steel door.”

He had received his Ph.D. in nuclear physics at CalTech and was well versed in the strengths and weaknesses of the microwave sniffer. For instance, they now knew how strong the emissions were—that was on the receiver’s readout—but without opening the door to the basement they could not know how far they were from the bomb. That meant they couldn’t map the microwave field, couldn’t learn how close they could safely get to the bomb before it would detonate.

Was there a dead zone? They couldn’t even tell that. Typically, a microwave sensor employs a Doppler shift, which means that the signal creates a constant pattern of microwave energy. The sensor looks for any change in the reflected pattern of that energy. A change occurs when an object within the sensor’s field moves. If you are standing absolutely still in the field, nothing will happen.

Of course,
some
motion had to be tolerable: what if the air-conditioning caused a curtain near the bomb to ripple? So the detector calculated the amplitude of change over time. Any change that was strong—or long in duration—would set it off, the exact definition of “strong” or “long” having been preset in the detector.

Also, as Payne knew, you could beat a microwave sensor if you knew how. There were ways. If you approached the sensor
very
slowly, you might not set it off.

But if you allowed your arms to swing at your sides even slightly, you’d probably get nailed, because your arms would be moving toward and away from the sensor at a greater rate of speed, a greater rate of change, than the rest of your body.

That wasn’t even a possibility now, however. Without seeing the bomb and being able to estimate its distance from where they were standing, they certainly could not risk approaching it.

And here was the bitch of it. How could you kill a bomb when you didn’t even know where it was?

CHAPTER NINETY-FIVE

Within fifteen minutes, the line of evacuees from the Network building dwindled and then stopped. Another announcement was made over the PA system, but ten minutes later no one had emerged.

None of the workers who had filed out of the building bore a remote resemblance to Baumann.

*   *   *

Inside the building, Sarah made her way up the stairwell. She had searched the first four floors, but no Baumann. And no Jared.

On the fifth floor, she walked silently down the empty corridor, checking office after office.

*   *   *

Dr. Payne made a swift calculation.

They were detecting microwave energy, but did that really mean they couldn’t move? He knew that the range of detection is always greater than the range of function—that is, they could “see” the microwave emitter, but the emitter couldn’t necessarily see them. There’s always a threshold of acceptable leakage, just as a microwave oven might leak microwaves, but people don’t necessarily get cooked standing in front of it.

Payne had examined the fusing system. He knew now how much energy it needed to set off the bomb. The more he repeated his mental calculations, the more sure he was that the amount of microwave energy leaking under the steel door was not enough, if reflected backward, to trigger the detector.

They were safe where they were. They could move.

*   *   *

“All right,” Dr. Payne said. “The safe line is on the other side of the door. There’s some stray microwave leakage, but we’re safe as long as we stay on this side. Everyone, back off from the door. You, Grant, and you, O’Hara”—he pointed at the DOE scientist who had lost it—“get out of here. I don’t want to see you again.”

On this side of the door, on this side of the safe line, they could move. The microwave sensor, he now realized, would detect motion on the other side of the door only.

This was good. This gave them considerably more room to maneuver.

This also meant they could remotely “look” at the bomb using a technology that remains to this day highly classified by the U.S. government. They used a device called a neutron backscatter, which emits a stream of neutrons at a very specific energy level. The stream is fired at the target, and then the backscatter measures the rate at which the neutrons come back at it—that is, the extent to which the neutrons are absorbed.

The neutron backscatter has the ability to penetrate metal liners and walls, so the steel door was not an obstacle. Using the same physical principle employed in an HED—a hydrogenous explosives detector—it looks for hydrogen. The neutron backscatter they were using was unusually powerful. Payne flipped the switch, checked the readout.

“Well, there’s explosive material there,” Dr. Payne muttered to Suarez. “A shitload of it, from what I can tell.”

“Now what do we do?” Suarez asked.

Dr. Payne did not reply; the truth was, he had no idea. He was winging it; in times like this you always had to wing it and trust your instincts.

“All right,” he said at last. “I want the generator moved out here.”

“You want to do
what
?” asked Suarez.

“Like I said,” Dr. Payne said. “The generator.”