Most people already know a few basic facts about radiation. They know, for example, that radiation can be passed through a human body to produce a photographic print that allows physicians to observe the presence of internal injury. They know that nuclear devices, for war or for peace, produce dangerous quantities of radiation. They know that our planet’s own sun emits radiation and that the earth shields us from the worst of it with its natural magnetic field. They know that a sufficient dose of radiation can be harmful, producing burns in the short term, cancer or other genetic mutations over time. Sunburns are your skin’s way of telling you to reduce your exposure to harmful solar radiation. Fewer people know that entire electromagnetic spectrum, from soup to nuts, is radiation. My suspicion is that sometime during the atomic era of the 1950s, American media figures muttered conflations around the stem of a tightly-clenched pipe. Perhaps adding “ionizing” to modify “radiation” for the sort found in the heart of Eisenhower-era nuclear devices was too much of a mouthful for prime-time television. Perhaps the distinction was unimportant when weighed against the urgency of the blossoming arms race. Whatever the case, the notion of high-energy radiation was sufficiently impenetrable that by the time it became a plot device for dimestore fiction, it ended up transforming mild-mannered research physicists into raging emerald smash-monsters. For those rare few who know the difference between ionizing and non-ionizing radiation, fewer still know that the line dividing them is neither bright nor clear. To understand why, please bear with me as I digress a bit into a little introductory nuclear physics.
You already know what an atom is: the smallest piece of matter that still retains elemental properties. Once you cut an atom of gold in half, it is no longer gold. It becomes something else. You also know that there are three main subatomic particles: protons, neutrons, and electrons. You almost certainly know that big honkin’ atom smashers can reveal the even smaller bits that these three are made of, but quarks and suchlike are more useful for astrophysics than for power generation or warfare. You know that protons define the element, and that neutrons define the isotope. You know that if the number of protons and electrons don’t match, what you’ve got is an ion. What you may not know is what any of that has to do with radiation. For that, we shall have to digress from our digression.
Ionizing radiation is the byproduct of hot-and-heavy, high-energy interaction between atoms. Cosmic radiation, for example, comes from stars dying or being born. Some of it is even from the Big Bang itself. There’s also radiation produced at the event horizon of black holes. All of these are pretty substantial high-energy events. But even the mundane fusion that happens in modest little yellow stars like our own is powerful enough to crap out highly energetic photons capable of causing ionization in any atoms unfortunate enough to be hit. If it helps, you can think of a photon as a teeny tiny little packet stuffed with energy. The more energy it carries, the greater the disruption at its destination. The same is generally true for other forms of ionizing radiation: a beta particle is just an electron when relieved of its energy, a placid alpha particle is a hydrogen nucleus, a chill neutron is… well, neutrons are different. Let’s return to neutrons later. Point is, from the point of view of an atom, the arrival of a bundle of energy could well be a pretty big deal. There are a few different reactions an atom might have, ranging from moving its outer electrons up a level or two for a little while, to heating up, to ejecting a new photon, to up and splitting the atom into pieces. It’s this last outcome that make neutrons so ornery.
You see, neutrons have no electrical charge. Alpha and beta particles tend to interact with electron shells, the bouncers of the subatomic world. They get turned away at the door. But neutrons and photons have a all-access backstage passes straight to the nucleus. And since neutrons are big and bad enough dudes to change the isotope of the atom they call home, they can destabilize a heavy nucleus even without being particularly energetic. In uranium, for example, the propensity an atom splits when struck with a neutron depends on two factors: the isotope, and the energy level of the free neutron. The relatively light U-235 is what’s known as a fissile, or a thermal fuel: it tends to split into fission daughters after it absorbs slow-moving, low-energy neutrons around 0.025 eV (eV is short for “electron volt”, the standard unit of energy used for particles). U-238 is a fast, also known as a fertile fuel. It tends to split when struck by a high-energy neutron in the 1 MeV (that is, about 40 million times more energetic than a thermal neutron) range. When a thermal neutron saunters up to a U-238 nucleus, it’ll usually just absorb it, becoming U-239. U-239 quickly decays into Plutonium-239, which you may recognize is commonly used as warhead fuel for nuclear weaponry.
Aha, you note: 40 million is a pretty big factor. What happens there in the middle? Well, at 1 MeV, a free fast neutron is pretty clearly in the “ionizing” category, while at 0.025, the thermal neutron is non-ionizing. In between is something called the “resonance zone.” Here’s where it gets a little funny. The resonance zone is a characteristic not of the neutron, but rather of the target isotope. Every isotope has a cross-section (the units for nuclear cross-section is “barn” as in “you can’t hit the broad side of a barn.” Clever, huh?) corresponding to the probability its nucleus will absorb (rather than simply eject) a free neutron. When you plot the probabilities (vertical axis) against the free neutron energy (horizontal axis), you almost always end up with a very wiggly region in the middle, where the probability of capture is extremely sensitive to neutron energy. You might even call it unpredictable. The folks who discovered this property dubbed this section of the plot the “resonance zone.” The existence of the resonance zone and its inconsistency across target isotopes implies that there is no clear boundary between ionizing and non-ionizing radiation. The practical upshot? When in doubt, wear sunscreen.
I caught the glint of the choppy sea reflected in Dave’s sunglasses. “I assume you do have sunscreen somewhere on this tub?”
“Tub? I’ll have you know I brought this little beauty back from little more than a keel and some deck plating with my own two hands. Check under the scullery.” Dave was adept at the fine and ancient art of bullshit, and I suspect it was a skill he’d been developing for some time.
He was right though. A hardly-used tube of vintage SPF 30 sat unmolested between a rusting air horn and a small stack of Ms magazines. “You want some of this?”
“Nah. I’d consider it a blessing to die of something as mundane as skin cancer. I expect it’ll be pirates. It’s usually pirates.”
“The hell, you say. Pirates? For real? This is the Pacific Northwest. How are there pirates here when there were none in their ancestral home of the Caribbean?” I thought briefly before correcting myself. “Well, none that I ever saw, nohow.”
“Yeah? Well, keep your head on a swivel around here. And make sure you’ve got a round in the chamber of-” he glanced to my hip. “What is that, anyway?”
“It’s a Springfield. Nine.”
“Nine millimeter? Didn’t you say you walked clear across the country?”
I stifled my growing annoyance. “What of it?”
He shook the jitter out of the mainsail. “No offense, but I can’t imagine making it that far without a little more stopping power at my disposal.”
I took a moment to unpack the freight embedded in his remark. “I assume you don’t do a lot of travelling.” I also assumed he didn’t do a lot of sitting around campfires or taverns shooting the shit with people bold enough to leave the confines of their home parish. But I didn’t want to press my luck so early in the voyage. “Imagine my surprise to discover pirates lurking along Vancouver Island.”
“The world sure has changed.”
“You can say that again.”
“The world sure has changed.” He smirked. I grimaced. “I suppose I expected the patterns to stick around.”
“The patterns? I’m not sure I follow.”
“You know, regional habits. Stereotypes. Patterns. Local culture, if you will.”
I couldn’t help but remember the brush with death Anika and I suffered in Texas. “So you expect what, gentle manners to hide deep-seated racial animus in Georgia and a fondness for pressed ham sandwiches in Miami or something?”
“Sort of.” A few dolphins breached nearby. Damned pests. “I was thinking more fundamental than just sandwiches though, you know?”
“So racism, yes. Sandwiches, no.”
“I’m not even sure that racism is especially fundamental. If I remember right, the southern states were colonized mostly by Scots-Irish. The fundamental characteristic of Scots-Irish is clannish belligerence.” He glanced at me with a tint of worry lining the blue in his eyes. “No offense intended.”
“I’m a mutt, but even if I were fresh off the boat from Glasgow, none would be taken.”
“Does Glasgow even have a seaport?”
“Seems like it should. The River Clyde ought to be navigable. How else would they ship out all the peat?”
He returned to the topic at hand. “Contrast them with New Englanders. Yankee types have the neighborhood, the church, or the school district as the next step up from the nuclear family. They’re thrifty, some might say miserly. They’re distrustful of outsiders, and pretty cold-tempered and surly as far as Americans go.”
I was getting intrigued by his characterizations. “How about around here?”
“Here? This side of the Cascades, maybe this side of the Rockies and north of the Columbia, I think the best way to look at this place is that it’s woman’s country.”
I wondered if he meant the neo-Amazon society in Yakima. “Woman’s country?”
“Yeah, there’s something kind of gentle and nurturing about this land. There’s never been much day to day hostility here. People don’t go out of their way to be rude to each other they way they might in that whole stretch between DC and Boston. You know what I mean?”
“I guess. But it’s not like the crime rate was ever any lower around here or anything. In fact, this region is over-represented in the serial killer community.” I had to suppress a grimly ironic chuckle at the phrase “serial killer community,” as if Ted Bundy and Ed Gein ran the local PTA chapter.
“Could be that’s part of it too. Literature is full of irate women slaughtering their foes in fits of vengeance. History too. A woman burned London to the ground in the first century AD.” He raised an eyebrow and glanced at me. “She had help.”
“So you expected the fundamental patterns of culture to stick around, but not necessarily the expressions? Have I got that right?”
“Yeah, something like that. I expect Texans to be independent and suspicious of career bureaucrats. I expect Midwesterners to be honest and loyal. I expect California to favor experimentation. You know, stable sorts of stereotypes that you can go check for yourself.”
“And I take it that you’re disappointed with the results?”
“Surprised, more like. Even the incessant culture war drumbeats have fallen silent. Time was, you could always rely on someone to chant the virtues of their political team while vilifying the bad guys. I don’t see too much of that these days.”
I hadn’t thought about it too much, but he was right. The blood had been drained from partisan politics. Even in the places I’d been that kept old first-past-the-post election traditions in place, the habit of bunting-draped campaigns conducted by a professional political class had been replaced by crops of part-timers who spent the bulk of their time tending farms or whatever other civilian pursuits suited them. “That is strange, isn’t it? Why do you suppose that happened?”
“Politics is hope. Right? And hope is dead.”
“Politics is hope? Where do you get that idea?”
“It is, man. It’s great, gooey, sappy, silly, punch-drunk hope. Hope-soaked candidates spend the better part of two full years wooing moribund voters for a wildly misleading popularity contest, the outcome of which produces identical results regardless of who wins. Everyone hopes until their hope glands are squeezed of every last drop.”
“Ew.” I was glad Anika had stayed at Friday Harbor. I did not want her to start using “hope gland” in everyday conversation.
“Exactly. ‘Ew’ is exactly right. Good riddance to bad rubbish. Though I have to say it’s like killing a cockroach with a shotgun.”
“How do you mean?”
“Hope is a pretty high price to pay to be rid of political preening. I still remember what it was like. Intellectually, I mean. I can’t resurrect the feeling. It gave me drive, purpose. I had a reason to get out of bed in the morning. Hell, this same situation we’re in now? I probably would have helped you out even if there weren’t anything in it for me.”
“Well, that’s awfully nice of you.”
“Nice. Yeah, nice. It was good to be nice, wasn’t it?”
“I think so. Yeah. It was good.”
“You know what, Sam? I think I’ll have some of that sunscreen after all.”
“Here you go, Dave.”
We saw no pirates. Not that day.