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 Replies: 98 / Views: 20,836 |
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Pillar of the Community
Canada
2784 Posts |
JeffMTampa here is a 20X microscope objective. here is tripling on and American nickle. you see the 20 one will see a lot less area. I like to search with a 5X objective. here is the image. something else my relay lens is a canon 250mm. its thread at the mounting end is 52mm .75 thread pitch so jeff see with a bellows. you can work your microscope objectives at half there magnification . merely by shorting your bellows. hope this helps.  |
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Pillar of the Community
Canada
2784 Posts |
i wanted to try the 20X on the 1977 nickle. the 2 sevens are linked together very neat.  |
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Pillar of the Community
 United States
3932 Posts |
Nice pics rocky! 20x gives a tremendous amount of resolution for analyzing these small details. I have a 40x that I use the same way, though I mostly use it for phono cartridge styli since 40x is really too high for coins. 20x is about the limit for me as a mintmark fills the sensor.
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Pillar of the Community
Canada
2784 Posts |
thank you ray. Ray wanted you to know. finally found a tripod ring for that beast of a lens. I would not dare mount my camera with that hanging on there. I know it would break the face off the camera. I know have the rings and helicords. ray looking through the lens at a coin. the detail is crazy.. I have a mount coming from the USA. I know this will handle it. I will share the results as soon at I get it mounted solid. I like the 20X I can take it down to 10X very easy. have a great one
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Moderator
Canada
10438 Posts |
If you need any closer - I have access to a scanning electron microscope...   This is an image I captured for Mike Diamond and one of his error articles, on a Peace dollar with solder contamination. The white specks are fragments of almost pure lead, the grey is normal Cu-Ag alloy. Scale bar in lower left is 10 microns.  "Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy ebay store
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Pillar of the Community
Canada
2784 Posts |
spp ottawa that is stunning. have a great one
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Pillar of the Community
United States
3932 Posts |
How do you know it is lead?
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Moderator
Canada
10438 Posts |
Quote:
How do you know it is lead? Because the analytical spectrum told me so. Scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) is a widely applied elemental microanalysis method capable of identifying and quantifying all elements in the periodic table except H, He, and Li).
"Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy ebay store
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Pillar of the Community
United States
3932 Posts |
So the SEM has an EDX attached? SEMs are not EDSs. SEMS shoot electron beams, while EDX do Xrays. I can't really tell what your SEM has attached since I'm not familiar with Zeiss SEMS.
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Moderator
Canada
10438 Posts |
Quote:
So the SEM has an EDX attached? Short answer: Yes. It is a research instrument I use where I work. Long answer: Here are the gory details... Zeiss EVO 50 series Scanning Electron Microscope with Extended Pressure capability. (up to 3000 Pascals). Includes a Backscattered Electron Detector (BSD), Everhart -Thornley Secondary Electron Detector (SE), Variable Pressure Secondary Electron Detector (VPSE), and a Cathodoluminescence Detector (CL). The Oxford EDS system (energy dispersive spectrometry) includes the X-MAX 150 Silicon Drift Detector, INCA Energy 450 software and the AZtec Energy 2.2 microanalysis software. SEM operating conditions: Standard working distance is 8.5 mm. High voltage (EHT) set at 20 kV, with a probe current of 400pA to 1nA. Filament current set to 2nd peak.
"Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy ebay store
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Pillar of the Community
Canada
2784 Posts |
well I went to my juck pail an found me another 1977 american nickle. well I know one thing the 7s are not all connected. here is the image.  |
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Pillar of the Community
United States
3932 Posts |
Ahh, so that beast pointing up at 45-deg to the right is the Oxford. I should have recognized it.
How much "free time" do you get on that equipment? Reason I ask is that there is an ongoing controversy in Numismatics over the content of the so-called "shellcase" Cents minted at the end of WW2. Many Cents especially from 45-S and 46-S exhibit very unusual and colorful toning, and it is believed this is due to trace elements left over from the used shellcases, especially the primers, which are a "witches brew". I've longed to have access to an EDX or a good XRF machine, but so far have not. Would you be willing to run a spectral analysis on such a coin to see what shows up in a surface scan?
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Moderator
Canada
10438 Posts |
Not a whole lot with the SEM, but, I do have a research grade benchtop XRF in my own office, that I have access to pretty much anytime. That would be pretty easy to do.
"Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy ebay store
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Pillar of the Community
United States
3932 Posts |
Do you have any shellcase Cents? Would be good to compare a Cent from just before the war to one from just after, say a 1942P with a 1946-S. Most of the shellcase Cents (maybe all) were minted in SF. Do you need me to send you examples for the analysis? What is the smallest spot size of your XRF?
Contact me for photographic equipment or visit my home page at: http://macrocoins.com |
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Moderator
Canada
10438 Posts |
I am in Canada. So the answer to your first question is "no". Secondly, given the XRF would be in "Alloy Mode" detection limits are quite high (only two decimal places of a percent). You would get far better results using Two Cents as "sacrificial lambs" and subjecting them to a proper chemical analysis (INAA or ICP-MS by laser ablation), especially if you are trying to use trace elements to demonstrate your hypothesis. Otherwise, a simple comparative test would be easy to do. If we were not using mint state coins - I would grind one side of the cents completely flat, so that fresh, bare metal was exposed, and a flatter surface also means less attenuation of the XRF beam (again, sacrificial lambs). "Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy ebay store
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Posted 05/27/2020 12:00 pm
