‘“E” is the energy released; “m” is the mass of the material used, and “c” is the numerical value of the speed of light, which is then squared. There’s no need to bother about the units involved; suffice it to say that the value of “c” squared is very high, which is why “E” is so vast.’
Hillsworth resumed his seat. ‘Now, to build a nuclear weapon, you must first of all find some suitable material. It must be fissionable, which means it must be able to be readily converted into other elements, with the consequent release of energy, which in practice means that it must be one of the very heavy radioactive materials, like uranium or plutonium. Radioactive materials, as the name suggests, emit sub-atomic particles and certain types of radiation and some, like the isotope uranium 235, have what is called a critical mass. To put that in simple terms, if you simply assemble more than a certain amount of uranium 235 in one place, it will go critical and a nuclear explosion will result. That, in a nutshell, is the theory of the atomic bomb. Simply find yourself enough uranium, smash it all together at the desired time and place, and wait for the bang.
‘The mechanics, of course, are much more complicated, which is probably just as well. The normal detonation methods utilize shaped charges, amongst other things, which enable a bomb to be produced using substantially less fissionable material than in the early days. The bombs I’ve mentioned so far are fission bombs, where a heavy element is broken down into two or more lighter elements. The hydrogen bomb, on the other hand, combines hydrogen atoms to produce heavier elements, in exactly the same way as the sun functions. Do you want me to go into that as well?’
‘Thank you, Professor. I would appreciate it.’ Richter had learnt nothing new, and nor did he expect to at that stage of the discussion, but one of the first rules of friendly interrogation – that is, interrogation of a non- hostile subject – is to ask so many questions that it is difficult for the person being questioned to discern what you are really trying to find out. As far as Richter was concerned, the more Hillsworth said the better, and he seemed to be settling nicely into his lecture routine.
‘Right,’ Hillsworth said. ‘A hydrogen bomb uses a fission trigger wrapped in hydrogenized material to initiate a fusion reaction.’ He paused as the sound of muffled ringing became audible.
Richter muttered an apology and retrieved his cellular phone from his jacket pocket. ‘Richter,’ he said.
‘This is the Delivery Section,’ the voice at Hammersmith said. ‘We’ve just received a category-four delivery for our main customer.’
On an open line – even for a call routed to a GSM digital cell phone, which was effectively scrambled by the transmitting cell – the proprieties had to be observed. ‘Main customer’ was America, and a ‘category-four delivery’ was code for DEFCON – DEFence CONdition – FOUR.
There are five stages in the DEFCON process. The normal peacetime state is DEFCON FIVE; DEFCON ONE means that the American armed forces are in a state of maximum preparedness for combat, or are actually at war. DEFCON FOUR kicks the American military machine into a significantly higher state of readiness, and is the inevitable precursor to any outbreak of hostilities.
‘Oh, shit,’ Richter replied. ‘When?’
‘About twenty minutes ago.’
‘What action?’
‘Back here as soon as you’ve finished where you are.’
Richter snapped the phone closed as Hillsworth got up and made another drink, then he cut to the chase. ‘We have heard, Professor, that the Americans are starting to experiment with a new device which will produce about the same yield as a conventional nuclear weapon, about five megatons, but emit little or no radiation. I can’t reveal the source of this information, and we have at present no idea of the way in which such a weapon could function.’
Richter couldn’t tell him the source of the information principally because no such information had been received. Hillsworth sipped his tea slowly, looking keenly at Richter over the rim of his mug, then smiled. ‘I thought the Americans were on our side?’
‘They are, Professor,’ Richter replied, ‘and that’s why we’re interested. You always know what an enemy will try to do. It’s much more difficult to tell what your friends are intending, which is why we always look very carefully at any rumours we hear.’
Hillsworth nodded. ‘Very wise, no doubt.’ He looked thoughtful. ‘It’s an interesting idea, but unfortunately impossible.’
‘Impossible?’ Richter queried.
‘Yes. The physics won’t let it work. Whenever a nuclear explosion takes place, radiation products are emitted, and there’s nothing anyone can do to stop that happening. The radiation is as much a part of the equation as the uranium or plutonium.’
Hillsworth paused and scratched the back of his neck. ‘As we’ve briefly discussed,’ he continued, ‘there are three principal types of nuclear weapon: the fission bomb, the fusion bomb and the neutron bomb, which is also a fusion device. All emit radiation of various sorts, including gamma rays, x-rays, alpha particles and neutrons. In fact, the neutron bomb is specifically designed to emit huge quantities of high-speed neutrons which are lethal to all living things, but it’s only a tactical weapon, with no strategic potential.’
‘Why is that?’ Richter asked.
‘Because in a conventional nuclear weapon the neutrons released when the weapon detonates are absorbed to increase the energy of the explosion, to increase its yield. In a neutron bomb, the neutrons are allowed to escape, which severely limits the maximum possible size of the weapon.’
‘How high a yield could a neutron bomb have?’
‘The theoretical limit is about nine megatons, but most neutron devices were designed to be fired from large-calibre artillery pieces or mounted on small battlefield-use missiles, so it’s usually down in the few kilotons range. As I said, it’s strictly tactical in its application.’
‘And what about the radiation?’
‘It’s known as an Enhanced Radiation Weapon or ERW, and was always intended to be used to defend the West against a numerically superior attacking force. The neutrons would kill the attacking troops, but the low yield of the bomb means that it would cause little structural damage, which could be important if you were fighting on your home territory. And the radiation dissipates quickly, which could also be an advantage.’
Richter was, he thought, perhaps not actually able to see the light at the end of the tunnel, but he was at least beginning to make out the tunnel walls fairly clearly.
Anton Kirov
‘Not another change of plan?’ Valeri Bondarev asked, somewhat peevishly.
Colonel Zavorin nodded. ‘I don’t like it any more than you do, Valeri,’ he said. ‘I am running to a schedule, but it is dictated by Moscow.’
‘So,’ Bondarev said. ‘Now we do not go to Tunis either.’
‘No. We have been told to head straight for Gibraltar, and to signal Moscow with our estimate as soon as possible. My signalman has already cancelled our berth at Tunis.’
‘Thank you very much,’ Bondarev replied, with patent insincerity.
‘So what’s happened to the neutron bomb?’ Richter asked.
‘Well,’ Hillsworth said, ‘it’s always been very controversial, because it’s a people-killer. It was specifically designed to decimate enemy troops, and its intended deployment by the Americans in Europe caused an uproar. The Russians apparently thought it was unfair that their vastly superior invasion forces could be defeated by a handful of troops armed with nothing more exotic than howitzers and a few rockets.
‘The fact that the weapon only had defensive potential and so would only be used to kill the Russian hordes if those same Russian hordes first swept into Europe riding main battle tanks was deemed to be irrelevant. The Americans didn’t deploy the weapon, although they did stockpile them in America to be used in the event of hostilities over here.’
‘And the Russians? Did they build any?’
Hillsworth nodded. ‘Of course they did. In the nineteen eighties they announced that they had built and tested neutron weapons. What the state of play is now I have no idea, but I strongly suspect that somewhere in Russia some new kind of neutron bomb has been tested in the fairly recent past.’
