Category Archives: Radiation

North Korea tests a bomb

Obviously, I can’t say anything about what NK did. You can get as much on the news as I can. However, we should talk about how a Nuclear weapon and atomic bomb are done.

It isn’t as simple as stealing a bunch of “radioactive” materials and … boom! That is the good, ole fashioned, dirty bomb.


Frankly, nails do more damage. We can argue, but I’d win. I don’t feel like it today. Any bomb is bad, a “Dirty bomb” isn’t as bad as blowing people’s limbs off.

The reasonable fear we have is from Fission and Fusion bombs. Fission being the simpler, or Atomic Bomb. One simply holds two near-critical masses of Uranium close together and the critical mass generates heat. Hold it close enough, long enough, you have a bomb. (the techniques are well established, but very difficult to master.)


The United States, of course, has mastered them.

NK is claiming it produced a Thermo-Nuclear event. This means it heated Tritium, or Deuterium Tritium mix, to fusion temperatures. A Fusion bomb can be much larger than a fission bomb. Thousands of times larger. Or, they found a cool word in the dictionary, that they thought was a synonym for Atomic Bomb, and decided to use it.

Look ignorance is on both sides. We (US, SK, and China reported numbers) measure nuclear events with a seismic detector. An American reporter announced this reported event as an earthquake detected near the test site… I’m sure he can do traffic and weather together every hour, so he’s better than 90% of the public, but most people are ignorant of nuclear matters.


I’m not sure the NK “reporter” is much better.

Sure, a bomb in the hands of a crazy person is scary. NK is a scary place. Still, this wasn’t anything new or particularly interesting. Imperious Leader just figured that he had been out of the news too long. He needed to break the ISIS ISIS ISIS refrain. Heck, he didn’t know that Obama had already pivoted back to Gun Control. I doubt he’ll get as much time on the 6 pm news as Terry McAuliffe, my anti-gun governor.


Maybe you should focus on Knife control.–and-seaport/2016/01/04/f062e9ca-b2ea-11e5-9388-466021d971de_story.html



NASA views

I guess the good news is that NASA is still funding JPL missions to the outer planets. I’m a bit disappointed in their engine selection, some of their mission choices, but overall, it looks like decent return on investment.

This is a view of Pluto. Nothing too exciting, really. There is a certain uniformity in the ice flows that looks artificial, or at least weirdly large-scale crystal formations. Maybe it is just a feature of liquid flow in a very consistent environment. Maybe if we were closer, could get better resolution, we’d see the same pattern going down, showing natural fractal-ization.

So, any point to all this? yes. Choices matter. We do have information on Pluto because NASA has a budget and some will to use it. Most of the money is trapped in bureaucracy, much of the rest goes to Goddard for Earth exploration, but a little goes to JPL for its regular “big mission.”


Getting a nuclear reactor off the ground is still impossible, due to the Greens. A political choice to demonize nuclear power as a way of reducing the spread of nuclear weapons. Weapons are made in laboratories, not reactors. I keep hoping we’ll get sense in the US, but I don’t see much sign of that happening. Without 1) better launch technology or 2) refueling options. There isn’t much hope of a chemical rocket getting good results in the outer system. Too much Delta V to overcome. I’m still betting on a good nuclear reactor and ion drive for future deep-space missions. I guess I shouldn’t hold my breath.

The Future of Space Flight – Nuclear Propulsion

Nuclear propulsion is the simplest thing in the world. Obviously, the word NUCLEAR is scary. Apparently, the presence of this world has destroyed more projects than the Congressional Budget Office. But still, Nuclear Thermal Propulsion, to be specific, is easy peasy lemon squeezy.

nuclear thermal propulsion

Figure 1. The simple view of a Nuclear Thermal Rocket.

To start with, you get a tank of water. Then you boil it. Then you squirt it behind you. Yeah, that’s about it. You can use Helium, Hydrogen, Water, Liquid just about anything will work. The boiling process is run by a hot nuclear fission reactor.

Now, a couple of points:

  1. It doesn’t turn off and on like your stove. It takes hours to heat up and days to cool off.
  2. The waste is slightly radioactive.
  3. The thing could melt if run too hot without propellant. So, accidents could happen.
  4. You get a lot of thrust per pound of fuel.
  5. It is very efficient. ISP around 1000, twice as good as a chemical engine.
  6. It can last for tens of years, used carefully.

Well, looking at those points, what is the engineering argument? You probably shouldn’t light one off on the ground. They save literally tons of fuel, but with a high thrust, so you can use them in a gravity well. (Super high efficiency engines often have almost no thrust, gravity and atmospheric drag can defeat their efforts.)

The best locations for nuclear rockets are planetary orbits, possibly the occasional moon landing or Mars launch. Good bang for the buck.

So, when it comes time to move Man from low earth orbit (LEO) to geosynchronous earth orbit (GEO), or even the Moon. Nuclear Rockets are the best engineering choice.

Again, we first need to develop a solid method of delivering payload and fuel to a LEO space station. Then, we need to develop a strong work horse to deliver these payloads where they need to go. A deep-space dock at a location like L2 (shown below) might be the best choice. But satellites have lots of locations to go to, a good delivery service is worth hundreds of millions each year.


Figure 2. Lagrange (L) points on a map. The closest to Earth are L1 and L2. The others could simply be called “co-orbit with Earth.”

So, when you are looking at the future of space flight. It starts with delivery to LEO, but that is too close for real space work. To get human projects out of the gravity well, we need a workhorse. I recommend a nuclear rocket for near-space travel.

Mars Radiation on the Space Track


So, I have to thank Rain (boss of the Space Track.) She knows I’ll join in on anybody’s panel and make it more fun. BUT, I really want to talk about radiation. The Martian is “hot” right now, so Mars is a hot topic. (Obviously, Mars is only hot metaphorically or figuratively, because literally it is colder than ice.)

Is radiation important for a Martian Colony? Absolutely. Oddly enough, at NASA we were asked this question many years ago. I wrote the Design Specifications for Natural Environment (pronounced Disney) for some of these missions. I’d love to go over this in great detail…but we’ll wait till Sunday morning. See ya at Dragon Con.

Physics is Hard – or you don’t know what you think you know.

I got pinged on three interesting Physics Today articles this week.

1)   Focus: Electrons Not the Cause of Charged Grains
2)   Synopsis: Unexpected Impact from Medium-Sized Solar Flare
3)   Synopsis: Asymmetric Reconnections

There are actually interesting connections between these three papers, which only shows how weird my brain works.

1) We don’t actually know why rubbing a balloon on your head makes it charge up. SERIOUSLY. I’d assumed, as most people did, that it was something to do with electrons being pushed around… somehow. Ok, I gave it some serious thought some years ago when I was working lightning and found the theory lacking, but never had a good reason to push back. Raindrops do gather electricity, there are some good experiments to generate a charge.

The Kelvin Water dropper will generate a spark gap  – Wikipedia
 Drawing of a typical setup for the Kelvin Water Dropper

But water itself responds to positive and negative charge.

Seriously, the real effect in a thunderstorm isn’t a bunch of electrons jumping from raindrop to raindrop, but large electric fields generated by alignment of water molecules. So, in general, when talking about climate and 100 year models – people didn’t even have a good model for lightning.

2) Since we’re on the subject of Global Warming. The Human-Caused folks haven’t really dealt with how much influence the sun’s cycles have on the atmosphere. Major increases in ionization from even a relatively small event. I was expecting – around the auroral oval – that we’d see higher levels of heating and ionizing, but this paper seems to indicate strong charging as far south as England (I’d like better numbers here) as well as a significant influence in cloud formation. (At 20 km?) Well, I’ll take their word for it until I see their data.

Source – – gallery of images

3) What it the connection between the two papers? Electron Dynamics

The real problem with electrons is that they interact with everything, so they’re a buggar to study. One long-standing problem is assuming that they are tiny. Electrons are as large as their interaction width, which (according the the scientist at TRIUMF) he’s gotten to a mile wide in a superconductor.

This lets them do all kind of “spooky action at a distance” things, when we assume they can’t be in two places at once. They also generate magnetic fields, which influences group actions. Looking at electrons in space, we can start to see how they interact with magnetic fields, how groups of them interact with each other, etc. Seems easy enough, but it turns out we had it wrong all the time.

SO: In conclusion, Physics is hard. We learn a lot each year, but the hardest part is un-learning what we’re sure we knew last year.

A Dirty Bomb

Frankly you have heard about such things for years, without being told what the heck you were supposed to be afraid of. Short answer – nothing much.

Here is a prime example of a risk that made everyone in the radiation business crazy for a few days. Thieves car-jacked a transport of Co60 between the hospital and the storage facility. It has been recovered, but it was a worry for a few days. Thieves have not been found, but I hope they get medical treatment soon.

Cobalt 60 is a created material. It has a half-life of around 5 years (5.27) and decays into a perfectly normal Nickel isotope. If you have a Co60 problem, leave it alone for a couple decades and it goes away. It is created by bombarding normal cobalt metal with slow neutrons, a percentage of the Co59 gets transformed to Co60 – depending on a whole bunch of very boring variables, and a precentage turns back into Ni60. You do some math and at some point you pull the Cobalt metal out of the reactor or Californium source, or whatever, and put it into a Co60 machine – which is either in a pool of water or a lead box. Since Co60 produces a lovely spectrum of 1 MeV  (or call it 1000 keV) gamma rays, we usually call them Gamma cells. 

This is a picture of a pool with a Co60 source at the bottom. Safe as roses to be up here, but when the pulley drags the source out of the water, well, you’d get dead pretty quick. Which is kind of the problem with stealing gamma cells.

As a comparison, everybody has had a dental x-ray. They run from 20 – 100 keV. So at minimum, the gamma cell is 10 times hotter than a dental x-ray. The technicians wear lead coats to keep the exposure to a minimum, they do a couple dozen shots a day. Maybe a minute or two of exposure, total. Frankly, it was shown that x-rays will give you cancer – by Marie Curie – but she had hundreds of hours of exposure, with no shielding.

Gamma cells are hotter than x-ray machines, so don’t play with them without training. Certainly don’t put them in the back of your car and drive around for a few days. And don’t eat any of the pellets. That is all stupid-dangerous. If you are of the mind to do that, stay away from scissors and other deadly apparatus. (Eating scissors is also bad for you.)

Dirty bombs are what scare the normal folk, that some crazy would blow up a gamma cell, irradiating miles of landscape with “deadly radiation.” Yeah, pretty over rated. Mostly, radioactive materials – when blown up with simple explosive – are not much different than anything else. Yeah, it could take a few days to clean up and  you probably want to protect yourself from exposure if you are going to be handling it a lot, but not really worth “fearing.”

picture 9/11 families for a Safe & Strong America

I mean, a BOMB can kill you. If a terrorist is setting off a bomb, that is scary. So are terrorists shooting guns, or flying planes into buildings. Ok, lets set that – 9/11- as a Scale = 10. Scale = 0 is a bearded guy yelling scary Arabic words at you. Where should a dirty bomb fall? 


The bomb part could still take down a building, with people in it. An act by itself which could theoretically be an 8 or 9) SO, for arguments sake, lets let the dirty bomber blow up the mall at midnight, after the janitors leave, with a Co60 dirty bomb. The mall is ruined and it is a few months of clean up to get back to a parking lot. We’ll call that a 3 for 20 million dollars of property damage and zero casualties. What does the “dirty” add to the “bomb.” Physically? It means that the cleaners will have to wear protective gear, which multiplies time required by a factor of 4. SO, it would mean that the mall was out of action for a year. (and that you would have to endure a year’s screaming from ignorant media about the “deadly attack” even if it didn’t kill anyone) I mean, it doesn’t add a casualty, so I’d leave it pretty much a 3. In my book, the lone gunman with 1 kill is a lot scarier than 40 million in damages, but maybe somebody would say differently. 

Dirty bombs are only effective at making people stay out of areas. This is good for “site denial” attacks, such as shutting down an important bridge and costing people a lot of money. This is good for “Fear” tactics, so long as the media is a bunch of ignorant savages. Frankly, guns are more frightening – if you don’t own one. 


Yes, I actually went on a vacation. It was almost a mistake, but then … wham!… I was vacationing. I didn’t know what to do. The Memphis Zoo was fun. We spent about 8 hours walking around, my legs fell off, but we saw the whole thing.
The architecture was amusing, a blend of Egyptian, Log cabin, Native American Northwest, and Asian. (And a complete lack of understanding of the difference between Chinese and Japanese themes.)

I got glared at by a gorilla, charged by a grizzly, threatened by an ostrich, and generally made a pest of myself at all the local beasts. My wife will upload all the pictures, I promise there is one good for future blackmail in there…somewhere.

Of course, It would hardly be a party without radiation, right? I went and looked at the neutron generator at a facility I will let go un-named. (They have a state permit, but no need to antagonize the neighbors who probably think they are an electronics store.) They have a standing issue about radiation dose that I promised to give them a hand with. I made some measurements with their Bonner Ball neutron detector. I had some initial idea on what the results would be and I’ll publish them at a later date. They appear to be on track for meeting all their requirements on radiation. Still, it was good fun to be running around with a Ball and running MCNPx code. I’m going to try to make a pretty picture for them… not sure I can remember how. Durn these braincells, stuff I knew how to do a few years ago is slipping away. I’ll just have to spend some time playing with code. (durn)

The ball with the Geiger Counter on its back is a Bonner Ball…though there are other types of them.

I’ll tell you something. If you want to get good at a code, you have to learn to play with it. I suspect the same thing is true with golf or cards. Just using it the same way every time gets you very little advancement. Trying to do something that might be impossible…well… that teaches you a lot. (Like don’t try to divide conical sections with planes – weirdest problem I ever had.) I love to take MCNP and mimic other people’s work, do it backwards, whatever sounds like a fun problem. Then I save those pages for when someone asks me to do something crazy. Suddenly I remember how I did some dose calculations back in …. (ok, long enough ago that you might not have been born) … I look up the old methods, play with them a while, then produce a miracle. (Yes, Mr. Scott was a hero of mine.) If that is too vague a reference, I recommend you go get a dozen episodes of Star Trek – the original series – and play them. If you’ve never seen Star Trek… why are you reading my stuff?

“She cannae take much more of this Captain.”

I also received a letter requesting that I post the link to a link accumulator which has a lot of space links. I warn you off the top that it is a commercial site – obviously it sells Disneyworld tickets – but the links look good so if you are weak on REAL space history – as opposed to fake future history like Star Trek – you should check them out. (and buy me ice cream. I clearly am the loser in that bet.)

What have I left out? Silver Star where Corbin and I busted each other up with live steel. Yep, a real dang sword fight. I also worked on outrunning kids in my full armor all day. Heck of a week of vacation. I’ll get some pictures up, but we only got into town last night at 11 pm, got into bed around 12:30 am, and I was at work at 9 am. (yawn) Just an amazing vacation and the first I’ve had since… well… a long time ago.


I saw this on Sluggy Freelance, this is how my wallet feels about now.

Christmas is the one time of the year that the other people in my family get as much money spent on them as the baby does. (Only because I keep a constant count.) The Baby gets all the money…most of the time.

So, January is soon, with Cons and SCA events gallore. I’m working on rewriting B3ERS – an Event Resolution System (ERS) for a Cinematic Campaign. Should be a lot of fun. Contact me if you want to playtest, it should work fine.

What is up otherwise? Not bloody much. Dyani is the most perfect baby girl in the world, I’m a proud daddy, and it takes all my time. I get in a couple swordfights a week to stay in practice. I hit the gym once a week, to work the upper body. I don’t get a lot of sleep. 

So, I hope everyone is having a merry Christmas. I know I’ll be doing well. Tired isn’t dead. No zombie apocalypse so I hope everyone’s Mayan party went off without a hitch. Next stop, Ragnarok.

Space Weather – The Carrington Event

by Stephanie Osborn, “Interstellar Woman of Mystery,” Rocket Scientist and Novelist

In August of 1859, during historic Solar Cycle 10, something very strange began to happen. The Sun, as it neared solar max, grew unusually active. It produced prolific numbers of sunspots and flares, some of which were visible to the naked eye. This continued through the end of the month, until, just before noon on September 1, British astronomer Richard Carrington, just 33 and already acknowledged as one of England’s premier solar astronomers, observed an incredibly brilliant solar flare – a flare that was easily visible to the naked eye. In later times, this single flare became known as The Carrington Super-Flare. In his own words from his scientific records:

“…Within the area of the great north group [of sunspots]…two patches of intensely bright and white light broke out…My first impression was that by some chance a ray of light had penetrated a hole in the [projection] screen…for the brilliancy was fully equal to that of direct sun-light; but by at once interrupting the current observation, and causing the image to move by turning the R.A. [right ascension, an astronomical coordinate akin to longitude] handle, I saw I was an unprepared witness to a very different affair…The instant of the first outburst was not 15 seconds different from 11h 18m Greenwich mean time, and 11h 23m was taken for the time of disappearance [from the telescope’s view]. In this lapse of 5 minutes, the two patches of light traversed a space of about 35,000 miles…”

British amateur astronomer Richard Hodgeson also observed it; Balfour Steward at the Kew Observatory noted a “crochet” effect on the observatory’s magnetometer. (A “crochet” is also sometimes called a Sudden Ionospheric Disturbance, or SID. It is when a solar event produces an abnormally high plasma density – remember, plasma is like the stuff in your fluorescent lights – in one layer of the ionosphere. This in turn creates literal electric currents running through the ionosphere, which magnetometers pick up. It creates something of an invisible lacy pattern in the atmosphere, hence, I suppose, the term “crochet.”)

And all of the previous flares and coronal mass ejections had fairly effectively cleared the interplanetary medium between the Sun and Earth.

The enormous coronal mass ejection produced by the super-flare slammed into Earth in only 17 hours.

The resulting effects lasted several days.

What kind of effects?

Worldwide aurorae for starters. These aurorae were most noted in the Caribbean, where they had never been seen before. Colorado gold miners, awakened by the brightening skies, got up and began cooking their breakfasts, because they thought it was dawn. In Europe and the northeastern United States, newspapers could be read by the light of the aurorae.

Speaking of newspapers, the Baltimore American and Commercial Advisor spoke of the ongoing event in poetic terms. “Those who happened to be out late on Thursday night had an opportunity of witnessing another magnificent display of the auroral lights. The phenomenon was very similar to the display on Sunday night, though at times the light was, if possible, more brilliant, and the prismatic hues more varied and gorgeous. The light appeared to cover the whole firmament, apparently like a luminous cloud, through which the stars of the larger magnitude indistinctly shone. The light was greater than that of the moon at its full, but had an indescribable softness and delicacy that seemed to envelop everything upon which it rested. Between 12 and 1 o’clock, when the display was at its full brilliancy, the quiet streets of the city resting under this strange light, presented a beautiful as well as singular appearance.”

Those dealing in the business of telegraphy did not think so highly of the display. The incredibly intense event, a maximal G5 and S5 by any definition, created induced currents in telegraph wires that were simply impossible to control. Lines and pylons threw sparks, telegraph batteries were blown, telegraphers received severe shocks, and telegraph “flimsy” paper burst into flames.

And yet some telegraph systems continued to function, despite having no batteries to power them. The induced current was simply that strong.

This was the Carrington Event, the most powerful solar/geomagnetic storm ever to occur in recorded history. It was before the advent of electricity, or electronics, or integrated grids and networks, save for telegraph systems, with which it wreaked havoc. Imagine what effect it would have today.

Dibs on the story.   

-Stephanie Osborn