I don't have the PDF, but I did manage to dig up Table 2 from Taylor & Southon
Use of natural diamonds to monitor 14C AMS instrument backgrounds (click to embiggenize):
Let's compare this with Baumgardner's results from
Carbon-14 Evidence for a Recent Global Flood and a Young Earth (2005), table 4 (with pMC converted to fraction MC for direct comparison with Taylor & Southon; note that these are before "subtracting background" and T&S did not subtract background so they are directly comparable):
Sample ID | Geological Setting | Country | 14C/C (fraction MC) |
Kimberley-1 | kimberlite pipe (Kimberley) | South Africa | 0.00100.0003 |
Orapa-A | kimberlite pipe (Orapa mine) | Botswana | 0.00140.0003 |
Orapa-F | kimberlite pipe (Orapa mine) | Botswana | 0.00110.0003 |
Letlhakane-1 | kimberlite pipe (Letlhakane mine) | Botswana | 0.00120.0003 |
Letlhakane-3 | kimberlite pipe (Letlhakane mine) | Botswana | 0.00150.0002 |
Kankan | alluvial deposit | Guinea | 0.00110.0003 |
Baumgardner's table 5 is similar:
Sample ID | Geological Setting | Country | 14C/C (fraction MC) |
NMBclr1 | alluvial deposit | Namibia | 0.00390.0002 |
NMBclr2 | alluvial deposit | Namibia | 0.00250.0002 |
NMBclr3 | alluvial deposit | Namibia | 0.00210.0003 |
NMByel1 | alluvial deposit | Namibia | 0.00170.0002 |
NMByel2 | alluvial deposit | Namibia | 0.00120.0002 |
NMBbrn2 | alluvial deposit | Namibia | 0.00150.0002 |
Note that T&S's results are
all at least an order of magnitude less than Baumgardner's. This is another direct proof that Baumgardner's samples were contaminated. Wonder why Baumgardner didn't mention that?
Baumgardner's table 6 (same as 4 and 5 but with "lab's standard background" {which Bertsche demonstrated is seldom used} does contain some results comparable to T&S (from which no background was subtracted), but nowhere does Baumgardner translate these results into an age. Were he to do so maybe someone would notice that the "ages" are mostly well beyond the capability of the method today and are obviously not related to the age of the sample.
At
Are the RATE Results Caused by Contamination? Baumgardner writes:
quote:
What about the RATE diamond measurements? Bertsche alludes to the fact that the RATE team also tested diamond by placing diamonds directly into the AMS sample holder. Our tests were done in 2006 after the RATE book was published in 2005. We obtained results quite similar to those reported by Taylor and Southon in 2007. Our ten diamond samples displayed 14C values between 0.008 and 0.022 pMC, with a mean value of 0.014 pMC. Certainly these 14C levels are much smaller than what we obtained for our coal samples; so, caution is obviously advisable in their interpretation. Nevertheless, unless one has a philosophical bias against such a possibility, the most plausible explanation, astonishing as it may be to some, is that natural diamond contains measurable and reproducible levels of intrinsic 14C.
So they obtained results from 0.00008 to 0.00022 fraction MC, which we can see from the standard calculation { T = -8033*ln(fraction MC) } is from 76 kYa to 68 kYa, well beyond the accepted capabilities of modern instrumentation of 55 kYa to 60 kYa.
Baumgardner claims, at your reference:
quote:
It is important to emphasize that placing the diamonds directly in holes bored in the instrument’s cathode sample holder eliminates all of the potential sources of 14C contamination listed in Table 1 of Taylor and Southon’s paper except for items (1), 14C intrinsic to the sample itself, and (7) instrument background.
Nope. It does not eliminate 4 and 6 (where's 5?):
quote:
Table 1 summarizes seven major potential sources of pseudo-14C signal in AMS-based 14C measurements...
...
(4) Transfer background. 14C introduced during graphite transfer to sample holder.
(4.1)
Target/cathode contamination: 14C introduced from sample holder.
(4.2)
Manipulation contamination: 14C introduced during physical transfer/packing of graphite into sample holder.
(6) Storage background: 14C introduced at any point in the sample processing sequence from any containment vessel.
(6.1) Particulate contamination: 14C physically introduced from carbon-containing particulates derived from storage containers.
(6.2) Atmospheric contamination: 14C introduced fromCO2 in air or from out gassing from storage container
Note also that the contamination sources listed in Table 1 are not all of the possibilities.
Baumgardner's conclusion that intrinsic carbon is the only possibility is wrong.
At your reference he also writes:
quote:
Regardless of the actual cause, the glaring fact remains that Taylor and Southon detected levels of C-14 in the diamonds they analyzed that were all well above the intrinsic sensitivity of their AMS hardware.
Baumgardner is correct in that the detected levels are above the intrinsic sensitivity of the AMS. However, he has utterly failed to demonstrate that the signal must be intrinsic carbon, and there are still plenty of reasons to doubt that conclusion. His RATE measurements are obviously from some contamination, especially by comparison to his own later measurements, and his arguments that the detected levels indicate sample age are hollow.
Edited by JonF, : No reason given.
Edited by JonF, : No reason given.
Edited by JonF, : No reason given.
Edited by JonF, : No reason given.
Edited by JonF, : No reason given.