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The nature of Cosmic Rays which are everywhere in the vacuum of space, are mostly converted to particle showers at ground level. The comparison of high altitude radiation to the radiation emitted from a reactor is valid only to the extent that a Gray is a measure of radiation absorbed by flesh. Counts (scintillation counter) don't tell us much about the energy of the individual particles or how they transfer energy to flesh.

This explains the "50 mSv" claim. It's actually not quite what is represented by the industry.

https://hps.org/publicinformat...

https://hps.org/publicinformat...

That study has results within the margin of error. Multiple studies are needed to corroborate results in these cases. Other studies don't show the same results. A real challenge in getting the needed data is the fact that most people who are getting multiple CT scans, and therefore higher dose, are already in a higher risk group.

http://hps.org/documents/risk_...

"There is substantial and convincing scientific evidence for health risks following high dose exposures. However, below 50 - 100 mSv (which includes occupational and environmental exposures), risks of health effects are either too small to be observed or are nonexistent."

For Fukushima you're talking about a far smaller dose.

That's not the case. The total radiation released by Fukushima Daiichi is far smaller than Mayak or Chernobyl, but there are concentrations of radiation (from Cs-137 and Cs-134) as high as 30M Bq/m2 in the several kilometers of land Northwest of Fukushima Daiichi. This is equivalent 0.8 millicuries which puts it into the ballpark of the Urals EURT areas of 1.8-3.4 millicuries that were studied by the Soviets; high enough to measurably effect the life cycle of saprophage.

Only one problem, during the terrorist attack the entire building was destroyed by a volcano.

The land around Fukushima Daiichi does not fit your terrorist+volcano analogy. The land and around the plant is foothills and the water did not get far inland. The plant itself was build only after the site had been graded to within ~10m of sea level (which is probably the single biggest mistake implicated in the whole event.) So the surface fallout may be studied just fine.

The sea around Fukushima Daiichi may also be meaningfully studied despite the tsunami. One need only establish control areas that are similar to the Fukushima Daiichi area but well away; kilometers or tens of kilometers north and south of the plant and relatively free of radioactive contaminants. Post tsunami recovery of organisms may then be studied and comparisons between Fukushima Daiichi and these control areas can be made.

FYI: this work has been started and is ongoing. Unlike the Soviet case we won't have to wait decades for the cover-up to finally fail and the results to appear, either. Japanese and Western researchers are eager to publish about Fukushima Daiichi.

Totally wrong on the puddle, not bothering with the rest.

http://hps.org/publicinformation/ate/faqs/commercialflights.html

Nutshell:

"The corresponding annual effective dose, based on 700 hours of flight for subsonic aircraft and 300 hours for the Concorde, can be estimated at between 200 mrem for the least exposed routes and 500 mrem for the more exposed routes."

500 mrem is equal to 5 millisievert. So 100 msv is equal to 20 years of commercial airline employee exposure. In one hour.

Only about as toxic as lead according to the second google hit. I guess uranium hexafluoride is more toxic, but I couldn't find any comparisons that I understood.

For the moment, I'm more worried about mercury being dumped in the river by companies than the government driving uranium around, crashing, and poisoning me.

Space Micro doesn't list the prices of their components or systems, nor can I find any from anyone else. Honeywell don't list their prices either. Atmel seem to have dropped out of the field. Linear don't list the prices for their space-hardened stuff. Don't see any for BAE either, or Intersil. Empire Magnetics require a lot of personal data before they give you access to even the price classification information. Not the prices, just how they're classified.

You've got to allow for a year's worth of traveling outside of an atmosphere and then operating on Mars for the duration of the mission. This analysis of radiation for manned missions suggests you're looking at 3.5 mSv per day, then 20 rems per year in most of the places of interest.

Converting everything to rads, it's 0.1 rads per mSv and 1 rad per rem, so that's 12.75 rads to get to Mars if you assume a year-long trip, plus 20 rads for the mission, so anything with a rating of less than 32.75 rads is pretty much guaranteed to fail. However, over the course of a two years, the odds of there being a solar flare are not insignificant. To be safe, you want resistance to a further 400 rad. 432.75 rad is within the tolerance of most of the space-hardened components (some components can be taken up to 1000 rad, others up to 10,000). However, the cheapest space components would NOT survive. You're talking high-end on the space scale.

I'm going to figure that the top-line components will cost 100x that of their conventional counterparts, due to the higher-level of precision and QA that are required. It might well be a good deal more. In Russia, you've also got to pay for smuggling decent-grade hardware out of the US, as all of this stuff will be under massive amounts of regulation.

My guess is that the cuts would have saved enough that those doing the cost-cutting could buy second homes in Switzerland.

The article is filled with speculation and disinformation. Here are the research links on both backscatter and millimeter wave technologies, provided by TSA:
http://www.tsa.gov/research/reading/index.shtm

You can see in the John's Hopkins August 2010 assessment that passengers get less than 2 microrem from a scan. You get about 238 microrem per hour of flight, two orders of magnitude larger (per hour!):
http://www.hps.org/publicinformation/ate/faqs/commercialflights.html

Stick to the science. 6 to 100 cancers per year is pure speculation, and impossible to verify. I don't believe it at all.

The article talked about the laws of physics and chemistry, but failed to mention biology. And the truth is that the amount of radiation an astronaut absorbs each day in interplanetary space probably far exceeds the amount of radiation that anyone has received from the "catastrophic" Fukushima reactor leak. When your DNA is getting fried like that, you don't want to hear about year-long detours. Outside of the Earth magnetic field, the radiation dose is in the tens of Sieverts per hour. With shielding you can get that dose down to a fraction of a Sievert, but that's still not good. (source)

Think about it this way: Fukushima emergency workers are required to stay away from reactors for the rest of the year if they absorb a quarter of a Sievert. In outer space, you get that every hour. In the US, the annual limit for radiation workers in non-emergency situations is a tenth of a Sievert.

Might help http://www.hps.org/publicinformation/ate/faqs/radiation.html
"The SI system uses the unit of becquerel (Bq) as its unit of radioactivity. One curie is 37 billion Bq. Since the Bq represents such a small amount, one is likely to see a prefix noting a large multiplier used with the Bq as follows .." see web page for more
Then think about
http://www.zerohedge.com/article/summary-key-health-threats-fukushima-radioactive-substances

If you're so against protecting yourself, at least do it for your children, or the people around you, don't be so self-fish.
 

http://hps.org/documents/kifactsheetbrief.pdf

Eh, I still would find it concerning if I were a grunt in the area of a recent armor battle (or, say, an A-10 Gatling CAS strike). It also seems that chelation therapy isn't as effective for uranium as it is for other heavy metals. I also imagine there is less treatment data about acute uranium toxicity than there is for, say, lead. Again, I admit that my expertise in heavy metal toxicity is vanishingly small.

Please understand I am not a breathless radiation paranoiac. In fact, I disclaim my positions as opinion when appropriate and I didn't edit that WHO quote that indicated only a 1% marginal risk from spent-fuel sourced DU.

I am an advocate of nuclear technology. I live within 15 miles of a nuclear power plant and feel perfectly safe (with the exception of reports of how inept the machinegun-armed guards are). I would feel safe even if the plant were immediately adjacent to my home. This is just very different in my mind than exposure (pulmonary especially) to aerosolized, potentially spent-fuel sourced DU dust. More so than lead.

Perhaps we can civilly agree to disagree.

Beat me to it :)

But on a more serious note: a dental x-ray can vary between 5 and 170 micro Sievert (source: http://hps.org/hpspublications/articles/dentaldoses.html),
so this could be between 500 and 17000 Sievert. A rather large uncertainty in such a statement. Not that it wouldn't be lethal, since anything over 6 Sievert (acute dosis) is considered lethal (and even 1 Sievert acute will get you radiation poisoning - see Wikipedia).

What's with scaring people about dental X-rays, though? While I appreciate the need for an analogy, couldn't they have come up with a better analogy for this one? Like "equivalent to standing inside Chernobyl starting on the first day of the accident, for 15 months in a row"? (*)

That'd make the picture much clearer, I'd say.

(*) using 20 Sv for Chernobyl first day exposure (max value) and the average value for the potential exposure with the 100 million dental x-rays, which gives 8750 Sievert total exposure.

"The UV band in general is absolutely considered to be ionizing."

No, it is not "in general".

See http://www.hps.org/publicinformation/ate/q2111.html.

and http://ehs.uky.edu/biosafety/uv_radiation.html

and http://yarchive.net/env/ultraviolet_dna_damage.html

and http://www.osha.gov/SLTC/radiation_nonionizing/index.html#ultraviolet

and http://www.icnirp.de/PubOptical.htm

Again, vacuum ultraviolet is something people will never come into contact with since you'd literally have to be in a vacuum to do so.
So in terms of the UV that anyone cares about from a health standpoint, it is not ionizing.

You do realize the radioactive danger of any given substance is inversely proportional to it's half-life right? something with a half-life of a billion years is generally not all that dangerous. U-238 has a half life of about 4.47 billion years and is far less dangerous than U-235 or U-234. I would be perfectly content to have a brick of depeleted uranium as a paperweight on my desk. Enriched uranium on the other hand...

Also... uranium is no more chemically toxic than any other heavy metal, such as lead. If inhaled as dust, it becomes more of a problem as it bypasses the skin and accumulates rather than clearing out of your system. Alpha particles are easily avoided, but damaging.

According to the Health Physics Society, there is no concern for radioactivity and diet, including potassium-40.

http://www.hps.org/publicinformation/ate/q5944.html

http://www.hps.org/publicinformation/ate/q6254.html

According to the Health Physics Society, there is no concern for radioactivity and diet, including potassium-40.

http://www.hps.org/publicinformation/ate/q5944.html

http://www.hps.org/publicinformation/ate/q6254.html

Excuse me, Sir? With all due respect, you're full of crap. Not a single point in your post is correct. Conventional explosives are NOT sufficient to aresolise nuclear materials, conventional explosives are NOT sufficient to disperse the materials over a wide area, Uranium is NOT highly radioactive, some forms of Plutonium ARE reasonably radioactive but primarily degrade as Alpha radiation (effectively harmless since aresolising Pu-238 is difficult and ineffective), being near Uranium or Plutonium does NOT pose a significant health hazard, millions of people will not die, and you sir have become a pawn of terrorism. Just as the media has. There is no real-world basis for the claims you are making about dirty bombs.

If you want to save lives from radiation dispersion, stop coal plants from dispersing radioactive materials in their smoke. Stop people from smoking cigarettes. Stop the use of oil and natural gas. Stop foreign nations from performing nuclear tests. (The US and Russia already contaminated the world back in the 50s and 60s.) Because those are the REAL sources of contamination. Coal burning alone outweighs the effects of a dirty bomb by several orders of magnitude.

So with all due respect, please educate yourself before propagating misinformation.

It's easy to find information on astronomy, chemistry, physics, mathematics, radio, electricity, etc, etc, etc. But radioactivity? Not a chance. How close to I have to be to an exposed nuclear rod before I am "at risk"? 10 meters? 100 meters? A kilometer? In orbit? Give me graphs. Give me numbers. Help me understand.

The study of protecting individuals and the public from the potentially harmful effects of radiation is known as Health Physics. Every industry that uses radiation sources -- hospitals, nuclear power plants, materials engineering facilities, etc. -- employs health physicists.

I would recommend looking at the Health Physics Society web page and possibly contacting them. They are a professional organization made up of people in the field -- people whose jobs are to detect & measure radiation; inspect facilities; and write, understand & enforce various regulations.

http://www.hps.org/publicinformation/ate/q4856.html

I'm rather more concerned with the fact that the FCC started asking about wiring and suddenly all the airlines are inspecting like mad

Well, that's the FAA and airline safety is their job. They are supposed to be looking at real and potential problems and mitigating them.

I'm also rather more concerned with the fact that I cannot get a reasonable quote on the radiation exposure to passengers on international flights. The difficulty in getting that number makes me think that for some long-haul flights, air crew and possibly passengers are exceeding safe limits.

Have you accepted Google as your personal search engine? You should consider this and be at peace with yourself.

I'm also rather more concerned with "air rage", where passengers - usually drunk from the duty free - go berserk.

So the idea of a drunken madman either trying to negotiate his cell phone or trying to turn off Chatty Cathy's strikes you as a good idea?

With the increased restrictions on movement on aircraft, I imagine the death rate from deep vein thrombosis has also risen.

Your imagination exceeds your critical thinking skills by a large margin. Your Search Engine of Choice can bring you back to something resembling reality.

There have also been reports in the press about passengers being able to gain access to aircraft control wiring in some cases. Aircraft systems operate on ARINC busses, which are just very expensive RS-232 links with a published protocol.

"Sir, sir - I say, yes - you with the breakout box, oscilloscope and wire cutters - would you mind putting all that stuff back inside the fuselage panel and returning to your seat?"

Thanks, but I'll reserve my imaginative moments to trying to figure out how to smuggle some shigawire on board. "No mamm. I don't know what happened. On moment she was jabbering on her phone and the next time I looked up her hand was on the carpet."

Here you are. It's old, and unfortunately if you want to read the paper you'll have to go look up a paper copy: http://www.iop.org/EJ/abstract/0031-9155/19/2/089/.

Searching for radiation beneficial also gives a bunch of hits, though most of them are pretty shady. Radiation homeisis is another good search term (that turns up a lot of shady stuff). There have been some stories on Slashdot too, if you search here.

Here's an ask the expert type thing that puts it well: http://hps.org/publicinformation/ate/q5871.html.

The effects from low level radiation are so subtle (in either direction) that the studies are always right around the limit of statistical significance, and you tend to get conflicting results. So really there's evidence both ways. It's definitely not accurate to say that all radiation is definitely bad for you.

The expected hazard curve would be high while it's particulate, lower when it's settled, and the radiation from Enriched uranium isn't that dangerous. not good for you but not letha or sickness inducing.

Pretty much the same as DU, Lead, or any heavy metal. With a bit higher toxicity when in the air and a bit more dangerous once settled. But not drastically more so.

I think there are multiple techniques used to control X-ray production. Leaded glass might be one of them.

What's interesting to note is that although you generally think about the picture tube being the source of problematic X-rays, in reality it was some of the other tubes -- particularly rectifier tubes -- back in the guts of older TVs that really had issues. Since modern televisions usually don't contain any tubes besides the one you look at, we don't think about the others very often, but they were at one point a major concern.

This Q&A from the Health Physics Society describes the issue: "The three major sources of x rays from these sets were the picture tube, the vacuum tube rectifier, and the shunt regulator tube. The latter (designations 6EF4 and 6LC6) were a particular problem. Over a third of the 6EF4 tubes tested produced exposure rates above 50 mR/hr at a distance of nine inches, and exposure rates up to 8 R/hr were observed at seven inches with one defective tube!" Just to put that in perspective, 8 R/hr is like ~150 chest X-rays per hour, or like getting a whole-body CAT scan once an hour. Granted, you probably don't usually sit seven inches away from your TVs power supply, but it's still unhealthy. (And a lot of people's cats do...)

So really, sitting next to the side of that old (1965-70) TV could be a lot more hazardous than sitting in front of it.

The Health Physics Society has produced a fact sheet (PDF-format) for Po-210. The information is fairly basic, but it's a starting point if you want to explain about the nuclide to someone who isn't very familiar with nuclear science.

The kidney is apparently relatively resistant to the potential toxic effects of uranium, and relatively high intakes are required before any signs of chemical toxicity occur. Indeed, before the discovery and availability of insulin, uranium was used therapeutically for the treatment of diabetes; relatively high doses were administered by mouth to patients, but there were no reports of kidney toxicity.

Finally, it bears mention that uranium is only poorly absorbed from the gut, so even if a large dose is swallowed, only about 1% or so will be absorbed--sort of a natural protective mechanism against potential toxic effects on the kidney.

http://www.hps.org/publicinformation/ate/q1906.htm l

"Has been shown"? You are referring to the linear-no-threshold model, which is not agreed upon universally by any means. Radiation hormesis seems to have a decent amount of high statistical quality evidence backing it up, though the mechanism for a causal relationship is not fully understood.

Exposure seems to behave linearly over a certain range of dosage levels, true, but not necessarily for all dosage levels.

"One nice feature that it does have is a small, exempt-quantity uranium check source on the side of the case to verify function." - from The Health Physics Society

One 700 I've got measures 30 mr/hr from the test source at 2 inches (.3 on the x100 setting) and the other pegs the meter on x100. Both read the same. One originated at Seabrook Nuclear power plant, which I acquired in 1996 or so and the last calibration date on it is sometime in the late 80s, and the other was calibrated for the radiological department of a (somewhat) local hospital in 2002 (IIRC).

They have been used primarily on natural samples of minerals collected in the White Mountains. My point wasn't that the source is very strong, just that even a little bit of radioactive dust is something to avoid if you can help it!

Wiki says Marie died of leukemia, age 67 - not as old as I'd remembered.
It was probably caused by radiation:
http://hps.org/publicinformation/ate/q535.html
http://www.diplomatie.gouv.fr/label_france/ENGLISH /SCIENCES/CURIE/marie.html
http://www.lucidcafe.com/library/95nov/curie.html

As I recall, the original magazine article never claimed he'd built a working reactor. But evidently, his house is now a Superfund site:

http://hps.org/publicinformation/ate/q3501.html

I've read that Hiroshima and Nagasaki still experience cancer rates well above normal levels, and it's been 60 years since the bombing.

I'd be curious to see where you read that, as it doesn't seem to be true. The only increased cancer rates I've heard of are those of people who were actually there in 1945.

http://hps.org/publicinformation/ate/q3645.html

Q: Are there any current health concerns for people if they were to move and live in Hiroshima/Nagasaki for an extended period of time?

A: Literally millions of people have lived in and around Hiroshima and Nagasaki since the 1945 bombings. No adverse effects from the radiation have been identified, except in those who were present at the time of the bombings. There is no reason for concern about moving to or living in these areas now or in the future.

S. Julian, DDS, PhD

And, indeed, many people today don't know about those same properties.

Oh! Forgot this one:

I have a feeling they won't give you a consumer product with radioisotopes to play with at home...

Did you know that gun scopes, watches, and fun little keychains? Oh, and doctors inject you with radioactive materials for diagnostic purposes. And false teeth used to be lined with Uranium. (Gives it that shine.)

More radioactive products here. If you use Google, you should find a plethora of wonderful products!

There's a modest demand for tritium. It's needed to recharge H-bombs. Fusion researchers need sizable quantities of it. It's used for night lights in exit signs, watches, and gunsights. Tritium has a half life of about 12 years, so you lose 5.5% every year as it decays to helium-3. So a new product that requires tritium faces a major supply problem.

The hazards of tritium exposure aren't high, but some precautions are required. Cleanup procedures for a broken tritium exit sign are as follows:

When an Exit Sign Containing Tritium (3H) Is Damaged (broken with the release of 3H):

1. Evacuate the area immediately.
2. Ventilate the area to the outside.
3. Isolate the area; do not allow entry.
4. Identify all individuals possibly exposed to the H-3.
5. Individuals possibly exposed should immediately:
   • Shower with soap and water (or at least wash face and hands).
   • Change clothing (retain in plastic bag).
   • Drink plenty of fluids.
   • Collect a urine sample immediately and then 24-hour cumulative samples and follow Nuclear Regulatory Commission (NRC), state, or health physics consultant advice on where to send them for analysis.
6. Call the NRC Regional Office.
7. Call the State Radiation Protection Program.
8. Call manufacturer of signs for technical information.
9. Be prepared to hire a health physics consultant to deal with initial monitoring, decontamination, and disposal of the exit sign and contaminated materials.

   The protective clothing required for cleanup usually consists of gloves and booties. The broken sign should be placed in an air-tight container by a health physics consultant. If silica gel is available it should be placed in the container with the broken sign. The silica gel will collect tritiated water. At a minimum, the broken sign and any miscellaneous pieces should be double bagged and sealed in plastic. Disposal of the broken sign should be arranged through the manufacturer or a health physics consultant.

And people screw up, even with ordinary exit signs. Here's a Nuclear Regulatory Commission report from 2004:

• UNPLANNED CONTAMINATION

  USAF personnel in the Johnston Atoll in the Pacific were attempting to remove the "batteries" from an exit sign they believed to be battery powered. During the attempt to open the case, they destroyed the sign only to discover that it was a tritium sign. All tritium modules were broken.

  Five personnel were in the room at the time and all were potentially exposed to the tritium. The Radiation Safety Officer (RSO) isolated the room and the personnel clothing, etc. Pre-cleanup surveys indicated greater than 6 times the normal background survey readings in the room. The RSO double-bagged the sign and tritium module debris. The room and work areas were decontaminated. Post-cleanup surveys indicated normal background readings. Personnel uptake and dose evaluations are currently being assessed.

So, like the nuclear batteries of the 1960s, this will be a specialized technology of very limited application.

OK, let's talk shielding: an excerpt from http://hps.org/publicinformation/ate/q1094.html

Most beta radiation from radioactive materials will require less than one-half inch of paper or plastic to stop it. Less than one-tenth of an inch of lead would be required to stop the same beta particles, although we frequently do not use lead or other materials that have high atomic numbers for routine beta shielding because of a secondary process that occurs when beta radiation interacts in the vicinity of the nuclei of atoms. This process is called bremsstrahlung radiation production and results in bremsstrahlung x rays being produced (the process is actually similar to what occurs in the production of x rays in an x-ray tube when electrons are made to bombard a high-atomic-number target material). The bremsstrahlung production process increases with increasing atomic number of the material. The x rays are more difficult to shield against than the beta particles and, as a consequence, we often choose to use lower-atomic-number materials, such as plastic, to shield beta radiation.

I was reading a simlar thing about that here.
Did you go and ask these guys first? How dare you.

More worrisome, the x-rays being emitted out the front are carefully regulated for health reasons.
Information here and here. The dosage is extremely low, which is because glass is basically opaque to low-energy x-rays. If your friend spends a couple of hours inside sitting in front of (or behind) a CRT, while you spend the same time outside in the sun, you'll incur the higher risk of cancer, due to the sun's U.V.

'I don't think the public ought to lose a lot of sleep over the issue,' says nuclear physicist Tom Cochran of the Natural Resources Defense Council.

Because if it goes off in your neighborhood there is very little you can do about it anyway.

The dose to a person in the United States from working on a CRT for a year is less than a few mrem, which is about 1/10 of the dose from a chest x ray, or about the same amount you get in one day from natural radiation.
http://www.hps.org/publicinformation/ate/q1046.htm l

It is all in your head. I really suggest you read up more on this issue (on *informed* sources, not gossip) if you are truely worried about it.

See this source for example (emphasis mine):

"The dose to a person in the United States from working on a CRT for a year is less than a few mrem, which is about 1/10 of the dose from a chest x ray, or about the same amount you get in one day from natural radiation."

http://hps.org/publicinformation/ate/q1046.html

I found a couple of links from a couple of states.
Here
Here

Please note that it mentions putting the person in a sense of danger - I believe the link occurs when a person is in a perceived sense of danger - they can react in a defensive manner. So if a police officer thinks someone is targeting him with a laser sighted weapon, they can pull and shoot.

Hope this helps
Avi

Prolly not. Most things I've read indicate that even the tamer wavelengths of UV used in black lights can still cause cataracts I would imagine that the UV LEDs would cause problems too (with enough exposure) although there is not yet an LED out there at the right wavelength to do real damage (and be useful for things like steralizing things, or say, keeping water in water cooled PCs from getting slimy... if I'm wrong about this please post a link here as there are many that would like to know) There are many fun links (like here and here) on the fun effects of the different forms of UV. Most deal with tanning beds and sun, but I'm sure if you spend enough time in blacklight, the same applies.

I'm sure in the end most Slashdotter's will opt for more enertaining ways of going blind. >;^)

Here are a few links, thou varlet! ;o)

Safety. LCDs are safer to use because they have no electromagnetic radiation.

The only potential emission from any of them that we know may be hazardous is x radiation from CRT-type monitors. It is fair to say that flat-panel LCD monitors will not emit x radiation under any operating condition whereas CRT monitors have the potential for emitting x radiation if the high voltage is raised higher than the CRT is designed to operate at. One might be able to cause a CRT monitor to emit some x radiation by failing a circuit or component, such as the hold-down safety circuit, and misadjusting user and service controls to raise the high voltage.

What's more, LCD panels draw 40 percent less power than similarly sized CRT monitors, produce less heat, and do not emit electromagnetic interference or X-rays (which CRTs do), making them somewhat safer and cheaper to use in the long run.

Not that a laser pointer is particularly safe.

A little radiation is not really a hazard. In fact, some radiation is benefical. You may not be familiar with hormesis.

I suggest you read this:

this
and this
and this.

Quickly paraphrasing this from Walker's Physics, Volume II:

The RAD (radiation absorbed dose) is the amount of energy that is absorbed by an irradiated, regardless of the type of radiation. One rad equals .01 joule per kilogram.

More information is needed to have an indication of the biological effect a certain dosage will produce. This is called the relative biological effectiveness (RBE). Some values:

Heavy ions: 20
Alpha rays: 10-20
Protons: 10
Fast neutrons: 10
Slow neutrons: 4-5
Beta rays: 1.0-1.7
Gamma rays: 1
200-keV X-rays: 1

The biologically equivalent dose for humans, the REM (radiation equivalent in man), is just the dose of radiation times the RBE. So alpha rays have at least ten times the relative biological effectiveness than X-rays.

In California it's a felony to aim a laser pointer at an aircraft.

Laser pointers can blind pilots.

I would turn them all on at once and aim them at the moon and see if you can get it to explode! Just make sure you don't hit any aircraft.

Have fun!

According to this microwave oven safety page, the legal limit of leaking radiation for a new oven is 1 mW/cm2 at 5 cm from the oven (for a used oven, it's 5 mW/cm2). For a complete oven measuring 25x40x30 cm, that would be a legal limit of 70 W if it radiates uniformly in all directions. (The page mentions that it's rather rare for an oven to exceed the limits). For a used oven, I'd guess that the door seal is the most critical place, which would correspond to about 1 W for 1 mW/cm2 at 5 cm from the seal.

Well, more or less, every time you fly you are getting X-ray'ed, and always have. Flying exposes you to a lot of Radiation in general, due to being in the upper atmosphere for prolonged bits of time. A standard Business traveler over the time of a year gets much more than the 'legal' dose of Radiation than is allowed for Medical workers working around x-ray machines. So, point being, that the majority of the Radiation you're gonna be exposed to when flying will come from riding around at 30,000 feet (and possibly from eating the airline food) and not from the security machine. A link with more info Here