Can Radiation Be Seen When Contaminated?

[Morbius]

Apparently there likely was a glow, from Čerenkov radiation, the same that glows off fuel bundles under water in the IF bays.

In this case as Morbius says, I guess the scintilation medium is water, or moisture in the air.

Homer,

You need a pretty intense radiation field to see Cherenkov radiation - as in the radiation from an
operating reactor core, or a critical assembly, or some spent fuel that was fairly recently taken out
of the reactor.

Or in the case of the accidental criticality accident; such as those that occurred at Los Alamos with
bomb cores - you get an ionization flash - the radiation intensity is enough to ionize the air.

Dr. Gregory Greenman
Physicist

 

[334dave]

334dave,

Radioactive sources don't really glow in the dark - except on TV.

You need some type of scintillation medium around to get the glow.

The Mexico story is somewhat true - a hospital in Mexico disposed of a radiotherapy
machine used for radiation treatment of cancers - the radioactive material was ultimately
"recycled" into consumer products like table legs. The reason it was discovered was
because a truchk carrying the material passed through the monitors at Los Alamos National Laboratory:

http://www.window.state.tx.us/border/ch09/cobalto.html

Dr. Gregory Greenman
Physicist

OK you got me, i only finished hs..
in a watchmakers bench i bought there is a vile of radium, from way before my time, for to put on watch hands to glow in the dark..it is labeled as such..
so why would that glow? why would other sources NOT glow..
i under stand my tritium (H3 ?) watch has a gas that glows ..
i would hazard a guess that it is possible to have some thing around or mixed in that would glow from the ionizing radiation.. on the order of say..
like propane and natural gas have no order .. it is added..

on a side note..
i am surprised no one has informed then casual readers that the purity deep blue glow from reactor cores is from the partials exceeding the speed of light..

 

[mgb_phys]

The glow from tritium or radium is not the radiation. The glass is coated with phosphors which emit light when excited by the beta emission from tritium.
It's exactly the same as a TV, electrons from the CRT hit phosphors on the screen to give you the picture.

 

[Homer Simpson]

You need a pretty intense radiation field to see Cherenkov radiation -

Just for interest sake, that IAEA report says in the house where the Brazilian fellow dismantled the tube of Cs-137, just due to some small amounts on the ground, measured about 6 Gray per hour at 1 meter distance, (600 Rem/h I think?) which to me seems really unbelievably high. You'ld receive your allowable yearly dose as a nuclear energy worker in about 30 seconds standing in that house.

No getting that level of contamination past a rad detector.

(I'm certainly not trying to say that level is comparable to radiation levels off a spent bundle, nor do I have any clue what level would cause Cherenkov radiation)

 

[Mentallic]

Mentallic,

Are you looking for scientific accuracy in the MOVIES?

If the contamination were due to Pu-237; as per the movie's title; Pu-237 is indeed unstable; but it
converts to Neptunium-237 via electron capture. There is a VERY SMALL possibility; with a branching
ration of 0.0042% that the Pu-237 will decay by alpha to U-233. However, NEITHER of these decay
modes would be threatening to the family

Dr. Gregory Greenman
Physicist

While title Plutonium is for another matter in that movie. The source of radiation is unspecified if I remember correctly but it was because of a heavy gas leak in a nuclear power plant. Now if the movie were to have any credit for producing *some* scientific accuracy, the producers could argue that the leakage that irradiated this man was from another substance entirely (could there be any elements/isotopes that, if matter were exposed to its radiation, would too become radioactive?)

The Pu in the movie is a metaphor. The movie is not about radiation.

I don't want to get into great detail about the movie, since the only highlight of it all was when

Spoiler

The thugs mistaked the plutonium powder for drugs and began sniffing it

. But yes, the plot of the story is based mainly upon human psychology.

The Simpsons seems an accurate depiction of any large plant operation.

Especially when the gas is vented way out in the country - where no one cares - on the farm crops. How about when Homer's instinctive reaction to meltdowns, as being a veteran safety inspector, is to destroy the control console by throwing water over it
Homer always seems to solve his problems without any effort at all. My role model!

 

[Morbius]

OK you got me, i only finished hs..
in a watchmakers bench i bought there is a vile of radium, from way before my time, for to put on watch hands to glow in the dark..it is labeled as such..
so why would that glow? why would other sources NOT glow..

334dave,

Because the vial contains a mixture of radium and phosphorous. The radium emits alpha radiation
which excites the electrons in the phosphorous - and when they return to ground state - they emit
photons of light.

on a side note..
i am surprised no one has informed then casual readers that the purity deep blue glow from reactor cores is from the partials exceeding the speed of light..

In the water surrounding the reactor core, you see the blue Cherenkov radiation because electrons are
exceeding the speed of light IN THE WATER - they are NOT exceeding the speed of light in a vacuum;
that is forbidden by Einstein's Theory of Special Relativity.

Dr. Gregory Greenman
Physicist

 

[mgb_phys]

nor do I have any clue what level would cause Cherenkov radiation)

A single neutrino can cause Cherenkov radiation - there are telescopes that will detect that.
Cerenkov radiation in air is rare because air has a refractive index only slightly > 1, the particle has to be going very near light speed to beat this. It's more common in water because with n=1.3 you only need to go at 0.75c

The intensity of the Cherenkov light depends on the number of particles not their energy. Although the wavelength depends on the energy and your eye's sensitivity to light does depend on wavelength.

I wouldn;t have thought you would see Cherenkov in air from even an open reactor. A very strong source might ionise air enough to give a similair blue glow (like blue electrical sparks).

 

[Morbius]

The intensity of the Cherenkov light depends on the number of particles not their energy. Although the wavelength depends on the energy and your eye's sensitivity to light does depend on wavelength.

mgb_phys,

The wavelength of the Cherenkov radiation deos NOT depend on the energy of the particle,
except secondarily.

The photons of Cherenkov radiation are de-excitation of the transparent medium after being excited
by the charged particle. The reason that we see a blue glow in a swimming pool reactor does NOT
have to do with the energy of the high-energy particles from the reactor. The blue glow is due to
the properties of the WATER - the particular atomic transitions that are being excited.

The only requirement for the energy of the high energy particles is that they be of sufficient energy
to excite the particular atomic transitions in the water or other transparent medium.

Dr. Gregory Greenman
Physicist

 

[334dave]

mgb_phys,

The wavelength of the Cherenkov radiation deos NOT depend on the energy of the particle,
except secondarily.

The photons of Cherenkov radiation are de-excitation of the transparent medium after being excited
by the charged particle. The reason that we see a blue glow in a swimming pool reactor does NOT
have to do with the energy of the high-energy particles from the reactor. The blue glow is due to
the properties of the WATER - the particular atomic transitions that are being excited.

The only requirement for the energy of the high energy particles is that they be of sufficient energy
to excite the particular atomic transitions in the water or other transparent medium.

Dr. Gregory Greenman
Physicist

yes i knew of the changing of speed of light in water ..
the rest of your answer was most informative!
so.. leading to another wandering of mine..
as in a clear gem diamond the speed of light is even slower then in water
would we see a glow from the diamond that is different then in water under the same conditions?
i know many gems gain much enhanced changing of color and depth of color from exposure to fields..
what causes this?

 

[vanesch]

It is possible to "become" radioactive as well by neutron radiation that activates atoms in your body, but this is a minute amount (enough neutron activation in the body to be detectable would probably kill you).

In order to activate biological material enough for it to become a radiation hazard itself, I never did the calculation, but I suppose that the material must already be cooked by a neutron beam before this happens.

What would btw be the most "sensitive" activation reaction ?

Hydrogen turns into deuterium, which is not active.
Carbon will indeed turn into C-14 somewhat (neutron capture on C-13, which consists of just about 1% of all carbon), so that's a potential hazard.
Nitrogen, not really. Only N-15 could activate, only 0.4% of nitrogen is N-15 and then it turns into N-16 which has a half-life of 7 seconds into stable oxygen.
Oxygen, not really. Only O-18 (0.2% of all oxygen) can activate, and becomes O-19 which decays in 27 seconds to stable fluor.
Fluor, F-19 (100% of natural fluor) activates to F-20 which decays in 11 seconds to stable Neon.
Sodium, yes. Na-23 (100% natural sodium) activates to Na-24 which takes 15 hr to decay to stable magnesium, so for a day or so, this is a potential hazard.
Magnesium, not really, only Mg-26 activates (11% of natural magnesium) to Mg-27 which decays in a few minutes to stable Aluminium.
Similar for aluminium and silicium.
Phosphorus, yes. P-31 (100% of natural phosphorus) will activate to P-32 which takes 15 days to decay to stable sulfur, so this will be a hazard for a few weeks.
Sulfur is also a problem, because S-34 (4% of natural sulfur) will activate to S-35 with a life time of 3 months to decay to stable chlorine. So this is a genuine candidate for activation.
Chlorine is a problem too, because Cl-35 (75% of natural chlorine) will activate to a long-living (300 000 years) Cl-36.
Potassium is a small problem, because K-41 activates to K-42 with a lifetime of 12 hours.
Calcium is a night mare: Ca-40 activates to Ca-41 (lifetime 100 000 years), Ca-44 activates to Ca-45 (half a year).

There are a few others of course. You can verify all this on the nuclid chart of the NNDC.

 

[Morbius]

as in a clear gem diamond the speed of light is even slower then in water
would we see a glow from the diamond that is different then in water under the same conditions?

334dave,

Yes - the electron energy levels and their spacings in a diamond are different from the electron
energy levels and spacings of water. Therefore, you are going to see a different glow from a
diamond than what you see with water.

It's just like you see a different glow from a "neon light" when the gas inside is neon, giving you
a red glow; as opposed to the gas inside being krypton, which gives a green glow.

Dr. Gregory Greenman
Physicist

 

[334dave]

thank you Morbius!
had suspected it would glow...but thought it would be blue also..
i can not but wander at what color it could be!
but to other musings..
vanesch- in this thread there are discussions as to that only under the right conditions would objects become emitters of ionizing emissions..
you bring up some materials that this could happen to most easily..

i recall much fan fair once over exposing gemstones to enhance color
i have heard tails of some persons taking stones and putting them in the field of cancer treatment fields, ct machines and neutron beams ...
along with strong claims that this would cause the stones to become "hot"
some of the materials you mention are components of gemstones that affect color ..
what are your (or any ones !) thoughts concerning this?

also in some conversation some one spoke of setting off portals from med testing..
this happen to me personally and i caused much alarm for a short while..
at a slow nutron resurch center --
i was at a last point check point frisking station..
a few days before had received 'something' for cardiac testing ..
on placing my hand near the friskier it went off..
i had much fun seeing how little of my self and how close i had to be to set it off..
health phisics come running and ...
well i was restricted in were i could go for a while to say the least..
i asked if my badge had fogging on it but was never told and was issued a new badge after testing showed i was not "hot" ..
another place was also told to loose my glow in the dark watch as it had a source in it..

NOTE: it is not fun to lay in lead box while the machine slowly moves over you..

 

[mgb_phys]

You can improve (some) gemstones by irradiation. Many coloured stones are Aluminium Oxide with traces of heavy metals to give the color, change the metals (or even just their oxidation state) and you change the color.
You probably need something a bit stronger than radiotherapy dose though http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/irradiated-gemstones.html

The alarms are really a demonstration of how sensitive you can make radiation detectors.
Imagine if an alarm went off at a hospital if a doctor entered with a single bacteria on their skin. Or a meat packing plant worker left the site with a single animal blood cell on their boots.

 

[Vanadium 50]

The reason that we see a blue glow in a swimming pool reactor does NOT have to do with the energy of the high-energy particles from the reactor. The blue glow is due to the properties of the WATER - the particular atomic transitions that are being excited.

I'm a little puzzled by this. One also gets a characteristic blue glow using glass. Why should that be?

 

[Gokul43201]

334dave,

Because the vial contains a mixture of radium and phosphorous.

Minor correction: the vial likely contained a mixture of radium and a zinc sulfide based paint/dye (not phosphorus). Zinc sulfide (when doped appropriately) is phosphorescent.

 

[Morbius]

I'm a little puzzled by this. One also gets a characteristic blue glow using glass. Why should that be?

Vanadium,

It has to do with what excited states of the medium are. It's NOT the high speed particle that is
radiating - it is the medium. The medium is being excited by the high speed particle and de-exciting
by emitting a photon. What is special about Cherenkov radiation is that all the photons from a given
high energy particle can interfere constructively. You get the constructive interference only because
the particle is faster than the photons in the medium.

But what color the glow is is due to the electron energy levels being excited in the transparent medium.

Just as in my example with "neon tubes" - neon glows red, krypton glows green, xenon glows blue,
mercury vapor glows blue...

Dr. Gregory Greenman
Physicist

 

[mgb_phys]

So do you ever see other colors in cerenkov or is that the particle energies needed to achieve the speed are high enough that they produce high energy uv-blue excitation states ?
Could they also give x-rays, if they excited a k electron?

 

[Morbius]

So do you ever see other colors in cerenkov or is that the particle energies needed to achieve the speed are high enough that they produce high energy uv-blue excitation states ?
Could they also give x-rays, if they excited a k electron?

mgb_phys,

Sure - you can get Cherenkov X-rays if you excite energy levels high enough:

http://www.iop.org/EJ/article/1063-7818/37/9/A18/QEL_37_9_A18.pdf?request-id=e43a04b0-bfc6-44b1-8141-3c249bea2d09

http://www.iop.org/EJ/article/1063-7818/37/9/A18/QEL_37_9_A18.pdf?request-id=e43a04b0-bfc6-44b1-8141-3c249bea2d09

http://www.spiegel.de/international/0,1518,367260,00.html

In fact, the shorter wavelengths are more prevalent:

http://en.wikipedia.org/wiki/Cherenkov_radiation

Unlike fluorescence or emission spectra that have characteristic spectral peaks, Čerenkov radiation is continuous. Around the visible spectrum, the relative intensity of one frequency is approximately proportional to the frequency. That is, higher frequencies (shorter wavelengths) are more intense in Čerenkov radiation. This is why visible Čerenkov radiation is observed to be brilliant blue. In fact, most Čerenkov radiation is in the ultraviolet spectrum - it is only with sufficiently accelerated charges that it even becomes visible; the sensitivity of the human eye peaks at green, and is very low in the violet portion of the spectrum.

There is a cut-off frequency for which the equation above cannot be satisfied. Since the refractive index is a function of frequency (and hence wavelength), the intensity doesn't continue increasing at ever shorter wavelengths even for ultra-relativistic particles (where v/c approaches 1). At X-ray frequencies, the refractive index becomes less than unity (note that in media the phase velocity may exceed c without violating relativity) and hence no X-ray emission (or shorter wavelength emissions such as gamma rays) would be observed. However, X-rays can be generated at special energies corresponding to core electronic transitions in a material, as the index of refraction is often greater than 1 at these energies.

Dr. Gregory Greenman
Physicist

 

[signerror]

Don't remember the isotope, but it was some type of radioactive vitamin (B3 maybe).

B12 (cobalamin) has a cobalt atom, and both http://www.nndc.bnl.gov/chart/reCenter.jsp?z=27&n=30 and http://www.nndc.bnl.gov/chart/reCenter.jsp?z=27&n=33 are used in radiology, so maybe it was an isotopically labeled B12, cobalamin-57Co or cobalamin-60Co?

http://en.wikipedia.org/wiki/Vitamin_B12

http://en.wikipedia.org/wiki/Cobalt#Cobalt_radioisotopes_in_medicine

Cobalt-57 (Co-57 or 57Co) is a radioactive metal that is used in medical tests; it is used as a radiolabel for vitamin B12 uptake. It is useful for the Schilling test.[2]

These isotopes' half-lives are many months, not "a few days". BUT... B12 is a water-soluble vitamin, and in general these are, rather than being stored in fatty tissues, regularly excreted with biological half-lives on the order of a few days... so maybe that's what the radiologist meant?

Just a guess. The other B-complex vitamins are all C,N,O,H,S, which doesn't have obvious radiology potential.