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Author Topic:   Does radio-carbon dating disprove evolution?
ChrisS
Junior Member (Idle past 5631 days)
Posts: 5
From: Melbourne, Victoria, Australia
Joined: 08-17-2006


Message 151 of 308 (341809)
08-20-2006 9:49 PM
Reply to: Message 144 by PurpleYouko
08-18-2006 1:07 PM


Re: An emerging pattern maybe?
There has been some early (1980's) theoretical and field work done on the production of (i) neutrons and (ii) Carbon 14 in "soils" which may be of some help. These papers are probably not available in the 'net but should be available in a good university library.
  1. Y.Feige et al "Production Rates of Neutrons in Soils Due to Natural Radioactivity", Journal of Geophysical Research 73,3135(1968)
  2. Mark W. Kuhn et al "Measurements of Thermal Neutrons in the Subsurface" Geophysical Research Letters 11,607(1984)
  3. Richard Zito et al "Possible Subsurface Production of Carbon-14" Geophysical Research Letters" 7,235(1980)
  4. W. Kutschera et al "Spontaneous Carbon-14 Emission from Ra-223" Physical Review C 32,2036(1985)
  5. D. Barker "Excess Carbon-14 Abundances in Uranium Ores: Possible Evidence for Emission from Uranium Series Isotopes" Geophysical Research Letters" 12,737(1985)
  6. A.J.T.Jull et al "On the Carbon-14 Content in Radioactive Ores" Chemical Geology(Isotope Geoscience Section) 66,35(1987)
If you can't access them I would be happy to discuss their content here.
Chris

This message is a reply to:
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AdminJar
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Message 152 of 308 (341810)
08-20-2006 9:55 PM
Reply to: Message 151 by ChrisS
08-20-2006 9:49 PM


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  • This message is a reply to:
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    PurpleYouko
    Member
    Posts: 714
    From: Columbia Missouri
    Joined: 11-11-2004


    Message 153 of 308 (341885)
    08-21-2006 10:25 AM
    Reply to: Message 147 by johnfolton
    08-19-2006 4:34 PM


    Is natural Berylium a neutron source?
    Beryllium is purified from minerals within the earth so in this purified state its said to beable to liberate 30 neutrons for every million hits from an alpha particle
    Same numbers that I came up with. You've been doing your research haven't you
    It forms various molecular compounds that due to the coloumb barrier no reason or evidence in the natural its releasing neutrons. Is there any evidence that beryllium molecular chemical compounds (not beryllium) that are found within the earth are violating the coloumb barrier?
    I really can't say if there is any evidence of it happening with naturally occurring beryllium or not at the moment. That is a very good question. If refined elemental Beryllium exhibits a different magnitude coulomb barrier than it would were it bonded to another element then this would indeed pose a possible problem for the hypothesis.
    I will see what i can dig up on the subject. I strongly suspect though , that Be compound will not exhibit any differences due to the usually ionic nature of bonds formed by alkali earth metals such as Be or Li.
    While searching for research on the subject I came across this reference.
    quote:
    Leo Szilard, and T.A. Chalmers, ”Detection of neutrons liberated from beryllium by gamma-rays: a
    new technique for inducing radioactivity,“ Nature, 134, 494-95 (1934), on 495.
    It would appear that Gamma rays can also induce neutrons when they impact Be atoms. I will attempt to pursue this line of investigation a little later.

    This message is a reply to:
     Message 147 by johnfolton, posted 08-19-2006 4:34 PM johnfolton has not replied

      
    PurpleYouko
    Member
    Posts: 714
    From: Columbia Missouri
    Joined: 11-11-2004


    Message 154 of 308 (341886)
    08-21-2006 10:26 AM
    Reply to: Message 151 by ChrisS
    08-20-2006 9:49 PM


    Re: An emerging pattern maybe?
    Thanks ChrisS. I will look into your references and see if I can get them from my local University library

    This message is a reply to:
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    PurpleYouko
    Member
    Posts: 714
    From: Columbia Missouri
    Joined: 11-11-2004


    Message 155 of 308 (341893)
    08-21-2006 10:39 AM


    Evidence for neutrons in soils and sands
    From the first reference given by ChrisS i was able to pull up the abstract pretty easily.
    quote:
    Production rates of neutrons in soils due to natural radioactivity. Feige, Yehuda; Oltman, B. G.; Kastner, Jacob. Argonne Nat. Lab., Argonne, IL, USA. Journal of Geophysical Research (1968), 73(10), 3135-42. CODEN: JGREA2 ISSN: 0148-0227. Journal written in English. CAN 68:116473 AN 1968:116473 CAPLUS
    Abstract
    The relative neutron (n) yield of several targets of light elements exposed to monoenergetic ionized He beams from the Argonne tandem accelerator was detd. for a-energies ranging 4.8-8.8 Mev. The ratio of the neutron yields for 5.3 Mev. are in agreement with published data on thick target yields obtained with 210Po a-particles. The av. (a, n) yield per a-particle of the natural radioactive series for some elements and for different soil compns. was calcd. from the results by assuming an (a, n) yield of 75 neutrons/108 a-particles of 2 10Po a for Al. If 3 ppm. 238U and 11 ppm. 232Th are assumed as representative of the earth's upper crust, a production rate of 6.7 0.7 n/g./yr. in sand and 13.5 1.3 n/g./yr. in granite is obtained. Addnl. 1.4 n/g./yr. will be generated because of the spontaneous fission of 238U. As the production rate of neutrons through interactions of cosmic rays with the earth's surface at sea level is of the order of 800 n/g./yr., these (a, n) reactions cannot be of any significance to exposure rates of human populations. They may be of some interest to geologists, however, and may be the main contributors to neutron fluxes in tunnels, deep caves, or mines, where cosmic-ray background is very low.
    Indexing -- Section 53 (Mineralogical and Geological Chemistry)
    Unfortunately I cannot access an electronic version of the full paper. (I work 3 miles off campus so actually going to the library is difficult)
    From one of the other papers, I got this.
    quote:
    Excess carbon-14 abundances in uranium ores: possible evidence for emission from uranium-series isotopes. Barker, D.; Jull, A. J. T.; Donahue, D. J. NSF Accel. Facil. Radioisot. Anal., Univ. Arizona, Tucson, AZ, USA. Geophysical Research Letters (1985), 12(10), 737-40. CODEN: GPRLAJ ISSN: 0094-8276. Journal written in English. CAN 103:218445 AN 1985:618445 CAPLUS
    Abstract
    The U, B, total C, and 14C contents were detd. in various U ores, including uraninite, pitchblende, carnotite, uranophane, etc. The 14C concn. was detd. using the tandem accelerator mass spectrometer and ranged (0.8-8.2) ’ 106 atoms/g. The amt. of 14C detected in a U mineral is proportional to the concn. of U in that mineral, with an av. of (2.2 0.5) ’ 10-5 14C atoms/1 U atom. These data are consistent with the assumption of direct 14C emission for 1 nuclei in the 238U decay chain with a branching ratio of (1.0-2.0) ’ 10-9 relative to a-decay. The uncertainty results from the possible prodn. of 14C from 11B(a,p)14C.
    Indexing -- Section 53-2 (Mineralogical and Geological Chemistry)
    This would appear to bear out the previously asserted point that C14 concentration in uranium rich soils is proportional to the Uranium concentration.

      
    PurpleYouko
    Member
    Posts: 714
    From: Columbia Missouri
    Joined: 11-11-2004


    Message 156 of 308 (341914)
    08-21-2006 11:52 AM


    Jackpot
    I think I hit the jackpot this time.
    This is by far the most informative information that I have come across so far.
    In This Article we see tables of low Z elements that will release a neutron via collision with alpha particles. There are actually a lot more of them than I had previously thought.
    Sorry for leaving this as a bare link. The darn thing is a pdf and doesn't easily lend itself to conversion to text.(Try loooking at the html version for a laugh)
    Here are a couple of google's html translations that i felt particularly amusing.
    The alpha decay process leads to the emission of gamma rays tlom unstable &ughters
    (see Chapter 1). Also, the alpha @rticles can ”prpduce neutrons through (%n) reactions
    with certain elements. This source of neuons ean be comparable in intensity to
    spontaneous fission if isotopes W@ high alpha decay rates such as 233U,2MU,238Fu,or
    241Amare pnt:
    This section describes thep@wtion
    of neutrons by (n) reactions
    and provides wrne guidelines for&kxdating@,expeeted neutron yield.
    Folloiving km two extiples ofn) Aactioni that occur in many nuclear fiel cycle
    And especially this one.
    When the alpha piirticle’dives at ahoter nucleus, the probabili@ of a reaction
    depends on the C@lue,e threshold enew, and the height of the Coulomb barrier.
    The Qdue
    is the ,diffiwim in bindingergh% between the two initial nuclei and the
    two final reaktion ”products! A!tisitive
    So now we know. It's all down to "the diffiwin in bindingergh% between the two initial nuclei".
    Bet you are all really relieved to hear that.
    As to the issue of there being a difference between the chance of a Be atom accepting an Alpha particle, depending on its chemical form... Consider the following.
    From table 11.4, the coulomb barrier of Be9 is 2.9 MeV
    From table 11.3, the average energy of an alpha emitted by the decay of U238 is 4.19 MeV.
    From this we can see that there is far more energy than is needed to overcome the coulomb barrier.
    If we compare MeV to the typical bond strengths of covalent bonds, we find that the bond strength is utterly insignificant in comparrison.
    For example, the strongest covalent bond known is the Nitrogen Nitrogen triple bond. It's strength is 945 Kj/mol.
    However we are looking at the strength of 1 bond, not a mol of them.
    945/6.022 E23 (Avogadro's number) comes to 1.66 E-22 Joules of energy required to break a single (triple)N-N bond.
    1 megaelectron volt (MeV) = 1.60217646 E-13 joules
    That means that one of our alpha particles (4MeV) has about 4,000,000,000 times the amount of energy needed to cleeve that covalent bond. Berylium bonds are a whole lot weaker than N-N so I think you get the picture.

    Replies to this message:
     Message 180 by JonF, posted 08-24-2006 1:28 PM PurpleYouko has replied

      
    johnfolton 
    Suspended Member (Idle past 5591 days)
    Posts: 2024
    Joined: 12-04-2005


    Message 157 of 308 (342211)
    08-22-2006 12:22 AM


    The earth shields the beryllium within the earth
    The earth has sediments and are they not shielding the beryllium from the alpha particle? In the air the alpha particle can travel a couple of centimenters before its energy has expired, yet within the earth is not the problem that "the alpha particle is immediately absorbed by the sediments"?
    The molecular compounds, nitrogen oxides (n14) would not produce neutrons and if beryllium did by chance get hit directly by an alpha particle. Would it not take 1,000,000 direct hits before 30 neutrons could be generated?
    Would not those direct alpha hits on the beryllium in an beryllium compound need to be not shielded by the surrounding sediments so the alpha particles energy would not be depleted in anyway below the coloumb barriers strength?
    Why would not the sediments that are not beryllium not immediately absorb the alpha particles energy depleting its ability to overcome the coloumb barrier?
    The sediments that are shielding the beryllium within the earth could explain why an alpha particle would not overcome the coloumb barrier?
    Edited by johnfolton, : No reason given.

    Replies to this message:
     Message 158 by NosyNed, posted 08-22-2006 12:53 AM johnfolton has replied
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    NosyNed
    Member
    Posts: 8996
    From: Canada
    Joined: 04-04-2003


    Message 158 of 308 (342220)
    08-22-2006 12:53 AM
    Reply to: Message 157 by johnfolton
    08-22-2006 12:22 AM


    Re: The earth shields the beryllium within the earth
    You keep bringing up reasons (that you more or less make up) why there can be no very low level of C14 produced by natural radioactivity.
    If it can't happen then why does the amount of residual C14 correlate with the radioactivity of the surroundings?
    In what way does this explain the high degree of correlations between C14 and other methods when the dates are in a range that C14 is appropriate for?
    Why is there only a problem when we reach the dates that we expect there to be very, very little C14?
    Do you think the earth is made up of solid lumps of one kind of mineral and then another? Do you see a big lump of uranium there and then a lump of berylium?
    The soil is a mixture of very small amount of all sorts of things. This way the low atomic weight elements are, in some cases, very close to the sources of alpha particles. And so is the C12 close to the neutron sources.
    There are very, very large numbers of atoms in a very, very small amount of soil and we only need to produce very low numbers of C14 atoms to give a residual reading.
    The sediments that are shielding the beryllium within the earth could explain why an alpha particle would not overcome the coloumb barrier?
    This shows that you have, at best, a most tenuous grasp of what is going on. The shielding by other elements in the soil would stop the alpha particle from reaching an appropriate target. The coloumb barrier is only an issue when the alpha particle actually reaches a target.
    It has already been shown the the coulomb barrier is then no problem.
    Do not ignore what has already been answered.

    This message is a reply to:
     Message 157 by johnfolton, posted 08-22-2006 12:22 AM johnfolton has replied

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    johnfolton 
    Suspended Member (Idle past 5591 days)
    Posts: 2024
    Joined: 12-04-2005


    Message 159 of 308 (342234)
    08-22-2006 1:58 AM
    Reply to: Message 158 by NosyNed
    08-22-2006 12:53 AM


    Re: The earth shields the beryllium within the earth
    There are very, very large numbers of atoms in a very, very small amount of soil
    correct
    The coloumb barrier is only an issue when the alpha particle actually reaches a target.
    incorrect
    Penetration and Shielding
    Alpha particles interact with matter primarily through coulomb forces between their positive charge and the negative charge of the atomic electrons within the absorber.
    Edited by Admin, : Shorten URL.

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    Percy
    Member
    Posts: 22391
    From: New Hampshire
    Joined: 12-23-2000
    Member Rating: 5.2


    Message 160 of 308 (342307)
    08-22-2006 8:52 AM
    Reply to: Message 157 by johnfolton
    08-22-2006 12:22 AM


    Re: The earth shields the beryllium within the earth
    johnfolton writes:
    The earth has sediments and are they not shielding the beryllium from the alpha particle? In the air the alpha particle can travel a couple of centimenters before its energy has expired, yet within the earth is not the problem that "the alpha particle is immediately absorbed by the sediments"?
    The various elements and compounds in soil and sedimentary layers are all mixed together. The alpha particle that hits a beryllium atom is not one that has completed a miraculous journey of several centimeters, but one from a very nearby atom of a radioactive element.
    The molecular compounds, nitrogen oxides (n14) would not produce neutrons and if beryllium did by chance get hit directly by an alpha particle. Would it not take 1,000,000 direct hits before 30 neutrons could be generated?
    I'll let PurpleYouko handle this one, but it seems to me that a direct hit is a direct hit, and that as long as the energy of the alpha particle is sufficient it should always result in a neutron.
    Would not those direct alpha hits on the beryllium in an beryllium compound need to be not shielded by the surrounding sediments so the alpha particles energy would not be depleted in anyway below the coloumb barriers strength?
    As explained just above, the alpha particle would come directly without any intermediate collisions from a very nearby radioactive element.
    --Percy

    This message is a reply to:
     Message 157 by johnfolton, posted 08-22-2006 12:22 AM johnfolton has not replied

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    JonF
    Member (Idle past 168 days)
    Posts: 6174
    Joined: 06-23-2003


    Message 161 of 308 (342319)
    08-22-2006 9:36 AM
    Reply to: Message 159 by johnfolton
    08-22-2006 1:58 AM


    Re: The earth shields the beryllium within the earth
    The coloumb barrier is only an issue when the alpha particle actually reaches a target.
    incorrect
    Penetration and Shielding
    Alpha particles interact with matter primarily through coulomb forces between their positive charge and the negative charge of the atomic electrons within the absorber.
    Wrong. The Coulomb force is not the Coulomb barrier. Try again.

    This message is a reply to:
     Message 159 by johnfolton, posted 08-22-2006 1:58 AM johnfolton has not replied

      
    PurpleYouko
    Member
    Posts: 714
    From: Columbia Missouri
    Joined: 11-11-2004


    Message 162 of 308 (342418)
    08-22-2006 2:19 PM
    Reply to: Message 157 by johnfolton
    08-22-2006 12:22 AM


    Re: The earth shields the beryllium within the earth
    The earth has sediments and are they not shielding the beryllium from the alpha particle? In the air the alpha particle can travel a couple of centimenters before its energy has expired, yet within the earth is not the problem that "the alpha particle is immediately absorbed by the sediments"?
    Of course the alpha is pretty much immediately absorbed by the sediment.
    The vast majority of alpha particles are going to hit something else than beryllium. It only takes a few.
    The molecular compounds, nitrogen oxides (n14) would not produce neutrons and if beryllium did by chance get hit directly by an alpha particle. Would it not take 1,000,000 direct hits before 30 neutrons could be generated?
    Sure the conversion factor of the alpha-neutron reaction is only about 30 parts per million. I just don't see whay that is a problem. There are many many billions of radioactive disintegrations in a single kilogram of soil in any given year. It only takes one or two to make a C14 atom in order to raise the background to a continuous level.
    Why would not the sediments that are not beryllium not immediately absorb the alpha particles energy depleting its ability to overcome the coloumb barrier?
    I'm sure they do in a lot of cases.
    Remember that an alpha particle from a high mass radioactive isotope has somewhere in the vicinity of 4-5 MeV of energy. Beryllium has a coulomb barrier of about 2.9 MeV. The alpha can interact with a whole bunch of stuff before it loses enough energy to prevent it overcoming beryllium's coulomb barrier.
    The sediments that are shielding the beryllium within the earth could explain why an alpha particle would not overcome the coloumb barrier?
    The sediments will certainly take away some of the energy from the alpha. The further it has to travel, the less energy is left.
    Again, though, all it takes is the odd successful transmutation to produce a continuum C14 background.

    This message is a reply to:
     Message 157 by johnfolton, posted 08-22-2006 12:22 AM johnfolton has not replied

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    PurpleYouko
    Member
    Posts: 714
    From: Columbia Missouri
    Joined: 11-11-2004


    Message 163 of 308 (342422)
    08-22-2006 2:26 PM
    Reply to: Message 160 by Percy
    08-22-2006 8:52 AM


    Re: The earth shields the beryllium within the earth
    I'll let PurpleYouko handle this one, but it seems to me that a direct hit is a direct hit, and that as long as the energy of the alpha particle is sufficient it should always result in a neutron.
    Not quite percy, although it might appear that it should.
    Almost all nuclear interactions like this are able to proceed along various different pathways. A specific pathway has a specific yield percentage.
    JohnFolton is correct that for ever million Alpha-Beryllium impacts, only 30 neutrons producing reactions occur.
    However these neutrons often impact other heavier nuclei resulting in "Induced fission" in some cases. Since fission often produces 3 or more neutrons, it becomes possible that a single Alpha-Be fusion can set off a cascade of 10 or more neutrons.

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    NosyNed
    Member
    Posts: 8996
    From: Canada
    Joined: 04-04-2003


    Message 164 of 308 (342429)
    08-22-2006 2:59 PM
    Reply to: Message 162 by PurpleYouko
    08-22-2006 2:19 PM


    Decay rates in soil
    There are many many billions of radioactive disintegrations in a single kilogram of soil in any given year.
    This feels very high to me. I'd have guessed at 1,000 to a million times lower. Is it right?
    Edited by NosyNed, : fix dbcodes

    This message is a reply to:
     Message 162 by PurpleYouko, posted 08-22-2006 2:19 PM PurpleYouko has replied

    Replies to this message:
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    PurpleYouko
    Member
    Posts: 714
    From: Columbia Missouri
    Joined: 11-11-2004


    Message 165 of 308 (342444)
    08-22-2006 4:10 PM
    Reply to: Message 164 by NosyNed
    08-22-2006 2:59 PM


    Re: Decay rates in soil
    This feels very high to me. I'd have guessed at 1,000 to a million times lower. Is it right?
    Dunno really. it was a "off-the-top-of-my-head" estimate due to limited time to do the actual math.
    Tell you what, i will do it noe and find out for sure.
    From my earlier post Message 100
    That means that for every kilogram of soil, there are 10 miligrams of Uranium.
    1 mol of Uranium (238g) = 6.02E23 atoms (Avagadros number)
    Therefore 10 miligrams of soil would contain 2.52E19 atoms of Uranium (sounds a lot doesn't it?)
    The half life of U238 is 4.47E9 (4.47 billion) years
    That means that half of the U238 present in soil right now will be gone in 4.47 billion years so a quick estimate (if it were linear rather than exponential) would be just a case of dividing the number of atoms lost in that time by the time itself.
    2.52E19 / 4.47E9 / 2 = 2.82E9
    That makes an average of 2.82 billion disintigrations per year from Uranium alone. The real number is much higher for right now since the real fit is exponential. Nearer to 10 billion.
    Now take into account the disintigrations from U235, Thorium, Radium, Radon and all of the other semi and meta-stable isotopes in the Uranium decay chain
    I'm not going to bother doing all the math for every one of them but I think you must get the picture by now.
    I think many many billions of disitigrations per year per Kg of natural soil is actually quite a conservative estimate.
    Scary isn't it?

    This message is a reply to:
     Message 164 by NosyNed, posted 08-22-2006 2:59 PM NosyNed has replied

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