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Author Topic:   New Dating Technique: ATTA (Atomic Trap Trace Analysis)
46&2
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Posts: 24
From: Kailua-Kona
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Message 1 of 15 (760547)
06-22-2015 1:53 PM


I was reading a bit about this technique on another forum, but it's a bit over my head. I was wondering if anybody is familiar with it, what it's advantages and disadvantages are, and is it our best/most accurate technique, yet?

And from the YEC crowd, what are your objections to it?

Here are a few links dealing with it:

http://indigo.uic.edu/...3/1-s2.0-S0016703712003067-main.pdf
http://arxiv.org/ftp/arxiv/papers/1101/1101.2933.pdf
http://www.phy.anl.gov/atomic/PUBS/pub2000-07.pdf

From what I can tell, it's an improvement over AMS measurements, measuring instead with lasers, used (I think exclusively, so far) on the isotopes of inert gases, specifically Ar39, Kr81, and Kr85. The primary improvement being eliminating some contamination issues. It seems to be a much "cleaner; less noise" measurement. Though I would imagine there would still have to be some background noise.

The relatively short half lives of these isotopes (particularly Kr85) makes it useful for geologically recent events. I would think that it would also be useful as another crosscheck for carbon dating.

It lists quite a few possible applications, not all of which concern dating. It mentioned using for testing water and ice, but don't get how that would work, unless it was for non-age-testing purposes.

It seems to me that it will be particularly useful for more accurate dating of very recent events (last couple hundred years). And of course, it's always good to have another test available when the geology creates limitations with other methods.

So, if anybody with a little more science training than I have would be interested in checking it out, and maybe putting it layman's terms for us, it would be much appreciated.

Edited by 46&2, : No reason given.

Edited by 46&2, : No reason given.


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Admin
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Message 2 of 15 (760548)
06-22-2015 3:37 PM
Reply to: Message 1 by 46&2
06-22-2015 1:53 PM


Would you mind adding your own brief description of this dating technique to your opening message? I know you say "it's a bit over my head," but you need only provide enough to give people a rough idea.

--Percy
EvC Forum Director

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46&2
Junior Member (Idle past 506 days)
Posts: 24
From: Kailua-Kona
Joined: 04-10-2014


Message 3 of 15 (760549)
06-22-2015 3:58 PM
Reply to: Message 2 by Admin
06-22-2015 3:37 PM


Sure, I'll review the sources and see what kind of summary I can come up with in the next 24 hours or so.
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46&2
Junior Member (Idle past 506 days)
Posts: 24
From: Kailua-Kona
Joined: 04-10-2014


Message 4 of 15 (760550)
06-23-2015 3:50 AM
Reply to: Message 2 by Admin
06-22-2015 3:37 PM


I've entered a brief summary of what I can glean from the papers. Let me know if there is something further you'd like me to address, and I'd be happy to do so.
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Admin
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Message 5 of 15 (760552)
06-23-2015 7:44 AM


Thread Copied from Proposed New Topics Forum
Thread copied here from the New Dating Technique: ATTA (Atomic Trap Trace Analysis) thread in the Proposed New Topics forum.
    
JonF
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Message 6 of 15 (760561)
06-23-2015 8:49 AM


I'm mostly interested in the dating portion.

The first paper you cited listed 85Kr dating as applying to 100,000 to 1,000,000 years, and noted this is beyond the range of 14C. That lower limit seems pretty high to me. But it isn't going to work for hundreds of years. I think that the last few hundred years stuff is for tracing movement of materials, not dating 'em.

Water and ice that have been isolated from the atmosphere certainly can be "dated"; the date would be the date of isolation from the atmosphere, not the date of the water molecules. Maybe not widely applicable. However, ice core dating does relay somewhat on 14C dating (that's why ice cores aren't used in the 14C calibration curves) , and this could be an independent way of calibrating them. The samples would be awfully small, far from 16 tons!

The 85Kr dating is fascinating and has obvious parallels to 14C dating. 85Kr is continuously being created. Presumably it's evenly distributed in the atmosphere and dtaeale artifacts are in equilibrium with the atmosphere. When they are isolated form the atmosphere, usually by burial, the 85Kr is no longer replenished and the amount decreases in the usual manner for radioactive decay while the non-radiogenic Kr isotopes just sit there. Measuring the ratio of radiogenic Kr to non-radiogenic Kr in a sample and comparing it to the atmospheric ratio tells you how long it's been isolated from the atmosphere.

It's comparable to Libby's earliest work on 14C. Has the atmospheric ratio been constant over those milennia? Wads the sample really in equilibrium with the atmosphere? What contamination possibilities are there in the ground in in the procurement and measurement processes? There probably are ways to calibrate it against geological dating methods as 14C is calibrated against other dating methods.

It seems to me that the laser is mostly a way of trapping and cooling the atoms. I didn't study the instrumentation description closely yet. But the overall breakthrough in instrumentation is measuring incredibly small ratios of radiogenic to non-radogenic isotopes of the same element.


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46&2
Junior Member (Idle past 506 days)
Posts: 24
From: Kailua-Kona
Joined: 04-10-2014


Message 7 of 15 (760577)
06-23-2015 12:21 PM
Reply to: Message 6 by JonF
06-23-2015 8:49 AM


The first paper you cited listed 85Kr dating as applying to 100,000 to 1,000,000 years, and noted this is beyond the range of 14C.

That first paper is the one I spent the least time on, but I don't think this can be right. The half-life of 85Kr is only 10.8 years.

Edited by 46&2, : No reason given.


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kbertsche
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Message 8 of 15 (760578)
06-23-2015 12:26 PM
Reply to: Message 1 by 46&2
06-22-2015 1:53 PM


This technique looks very interesting, but it is still in its early stages of development. It should allow much smaller sample sizes than at present with AMS.

A sample will still need to be chemically cleaned, processed, and put into an ion source. The process and ion source background levels should be about the same as with AMS. So this new technique probably won't allow us to date older samples than at present.

I suspect the main application of this technique will be to open up dating possibilities with new isotopes which are very difficult to measure at present.


"Science without religion is lame, religion without science is blind." Albert Einstein

I am very astonished that the scientific picture of the real world around me is very deficient. It gives us a lot of factual information, puts all of our experience in a magnificently consistent order, but it is ghastly silent about all and sundry that is really near to our heart, that really matters to us. It cannot tell us a word about red and blue, bitter and sweet, physical pain and physical delight; it knows nothing of beautiful and ugly, good or bad, God and eternity. Science sometimes pretends to answer questions in these domains, but the answers are very often so silly that we are not inclined to take them seriously. Erwin Schroedinger


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JonF
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Message 9 of 15 (760581)
06-23-2015 12:51 PM
Reply to: Message 7 by 46&2
06-23-2015 12:21 PM


My mistake; 81Kr is used for the dating, with half-life of around 229,000 years.
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NoNukes
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Message 10 of 15 (760582)
06-23-2015 12:54 PM
Reply to: Message 9 by JonF
06-23-2015 12:51 PM


My mistake; 81Kr is used for the dating

How does that change affect the comments in your previous post. Are most of them still applicable? In particular is 81Kr continuously created in the atmosphere?

Edited by NoNukes, : No reason given.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

History will have to record that the greatest tragedy of this period of social transition was not the strident clamor of the bad people, but the appalling silence of the good people. Martin Luther King

If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions? Scott Adams


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JonF
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Message 11 of 15 (760583)
06-23-2015 12:54 PM
Reply to: Message 8 by kbertsche
06-23-2015 12:26 PM


It appears to me that AMS is not involved. The atoms are cooled and trapped and then excited to fluorescence and a camera takes pictures.

{ABE} Fig. 3. Trap capture rate versus laser frequency detuning. (a) The integration time for each data point of the 81Kr peak is one hour, and 10 min for 85Kr. The atom is detected by collecting the 811 nm fluorescence on the cycling transition. Zero atom counts on both sides of peaks illustrate the immunity of ATTA to any contamination by other species. (b) For 83Kr, 878 nm fluorescence is recorded in the laser induced quenching procedure (see text for details). In isotope ratio measurements, the laser frequency is fixed to the top of the peak for each isotope in order to count atoms at the maximum rates.

Edited by JonF, : No reason given.


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JonF
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Message 12 of 15 (760584)
06-23-2015 12:55 PM
Reply to: Message 10 by NoNukes
06-23-2015 12:54 PM


They're all still applicable, just got the isotope wrong.
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46&2
Junior Member (Idle past 506 days)
Posts: 24
From: Kailua-Kona
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Message 13 of 15 (760585)
06-23-2015 1:18 PM
Reply to: Message 9 by JonF
06-23-2015 12:51 PM


It appears that even with the small ratio resolution, the measurement capability is still only good to about 6 half lives. Is this do to a low natural abundance of 81Kr?

Edited by 46&2, : No reason given.


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NoNukes
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Posts: 9341
From: Central NC USA
Joined: 08-13-2010
Member Rating: 2.5


Message 14 of 15 (760588)
06-23-2015 2:05 PM
Reply to: Message 1 by 46&2
06-22-2015 1:53 PM


And from the YEC crowd, what are your objections to it?

I imagine the YEC crowd's objection are largely independent on measuring techniques because they believe the entire idea of doing radiometric dating has the fatal flaw of assuming that decay rates are constant.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

History will have to record that the greatest tragedy of this period of social transition was not the strident clamor of the bad people, but the appalling silence of the good people. Martin Luther King

If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions? Scott Adams


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JonF
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Joined: 06-23-2003
Member Rating: 2.8


Message 15 of 15 (760590)
06-23-2015 2:16 PM
Reply to: Message 13 by 46&2
06-23-2015 1:18 PM


I'm not sure, but probably yes. It takes some pretty hotsie-totsie equipment to detect today's ratio.
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