From: King Of All Crackpots         Sent: 04-27-94 15:35
   To: All                           Rcvd: -NO-
   Re: Nonequilibrium Radiocarbo   Status: Public
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I got the following info from an article by Robert L. Whitelaw. [1]

                             Definitions

SPR: Specific Production Rate of C-14 atoms in the earth's 
atmosphere by cosmic radiation in atoms per min. per gram of 
total carbon in the earth's active carbon inventory.  This 
total inventory is defined as all carbon in the cycle from 
atmospheric CO^2 to living things and back again.


SDR: Specific Decay Rate of C-14 atoms in any specimin of a 
living or once living thing in atoms per min. per gram of total 
carbon in the specimin. For living things on earth today, this 
is approximately equal to 16 disintigrations per min per gram 
of total carbon which corresponds roughly to 1.4 atoms of C-14 
per trillion atoms of total C.

                     The Radiocarbon Dating Method

1) Cosmic radiation bombards the atmosphere with energetic particles of
   1 to 2 BeV.
2) Neutrons of 5 to 10 MeV are generated
3) Two reactions take place after the neutrons are slowed down
    14        14   1
   N  + n => C  + H    98% of reactions of neutrons of 0.4-1.6 MeV
    14        12   3
   N  + n => C  + H    Remaining reactions
4) C-14 oxidizes to form CO  and diffuses to produce a fairly uniform
                           2
 14  12
C  /C    oxide ratio                        2
5) The average neutron intensity is 2.6 n/cm -sec
                                    2
6) The know carbon inventory in g/cm  (7.25 in ocean carbonates, 0.59 in
   dissolved ocean organics. 0.33 in the biosphere, 0.12 in the atmosphere)
   yeilds a value for SPR of (2.6)(60)/8.3=18.8 atoms/g-min
7) SDR is 16.1 + 0.5 dis/g-min based on the 1950 half-life of 5568 yrs
               -
   (Libby's original paper appeared in 1952).  If the world was billions of
years old, the SDR should have long since come into equilibrium with the
SPR
8) Libby assumed the two numbers equal.  He later corrected the 16.1 figure
   to account for the C-13/C-12 ratio.  The new value was 15.3

In the noneqilibrium method od radiocarbon dating, it is not assumed that
the SPR and SDR are equal.  It, instead, assumes an exponential buildup for
SDR
starting from zero at creation.

Robert H. Brown has derived a formula for converting "radiocarbon time"
to real time [2].

                        -2.211(5.35 - T)  -1
R = T + 8.3 [ln(1-0.989e                 )  ]

where R is the radiocarbon date in thousands of years and T is the real
time before present (present = 1950) in thousands of years.  Unfortunately
he doesn't give a complete derivation of the formula.  He gives an equation
that must be calibrated to the Bible.  But there's no explanation for where
this equation came from.

Some examples of the conversion follow:

        T        R
        0        0
     3100     3160
     3700     3920
     4300     5150
     4900     8680
     5250    18320
     5350    42780


This method is apparently specific to the C-14 dating method so 
it would have no direct effect on geologic dating.  And, of 
course, if you don't accept the Bible [as factual], then you 
don't accept the calibration.

                             References

CRSQ-Creation Research Society Quarterly

[1] Robert L Whitelaw CRSQ March 1993 pg 170-183.  Note: This article
is really just an overview of various creationist papers on radiocarbon
dating.

[2] Robert H Brown CRSQ June 1992 pg 45-47.
--
Ray Cote