Can they find tungsten blocks buried inside a gold brick? As others said xrf only goes so deep. Or can the xrf detect the presence of foreign material buried in the middle?
I’m sure bank of Taiwan is trustworthy as they’re government bank.
I used to do electron microprobe which is like xrf, it reads out the elemental composition of a given material. But the sample must be prepared in specific way.
XRF will penetrate up to 20mm. A kg gold bar is less than 10mm thick.
So that other poster saying it will only work up to a few mm for exceptionally high end machine is wrong?
Actually I guess I can check bank of Taiwan again but I didn’t recall them selling gram bars, only seen 1 ounce of more.
Where are you getting that from? For the XRF instruments that dealers actually use? That’s far deeper than anything coming up online for gold. (Though it doesn’t seem like something prominently advertised by the companies making them.)
TL, can’t you look who you’re responding to? I said that. And why are you asking me? I literally said “I’m not sure” and “as far as I can tell from a quick look”.
The gold dealer I use demonstrated several sample pieces up to 10mm thick when I first met him which had a variety of known compositions – most gold-plated fakes, some lesser karat gold – and had no apparent trouble analyzing them. He said that’s how he’d been trained a couple of years earlier by ThermoFisher. He has long experience using other methods for assaying gold and is convinced XRF of 10mm thick gold bars – his bread and butter – is the most accurate. The machine he uses costs $10,000 US.
Thanks for clarifying.
Eh. I’m not sure. I’ve looked some more, and 20 mm doesn’t appear to be a claim that the manufacturer actually makes anywhere in its material.
There doesn’t seem to be much information available about actual limits, at least that I could find, and I can’t be bothered trying to figure out to calculate the X-ray penetration depth for gold. I did come across this line in one of the manufacturer’s presentations about the system:
The AuDIT algorithm determines whether or not a surface is plated. AuDIT can detect plating as thick as 8mm. Since most plating is in the 2-3mm range, this can usually detect plated objects. Heavily plated objects with a plating greater than 8mm thick will read as Gold Plate Not Detected.
So it looks like plated 10 mm bars might usually be detected as you said, especially if assayed from both sides and/or at multiple points, but I’m skeptical of the 20 mm depth. It feels too high for what’s primarily a surface analysis technique, and if the manufacturer of this particular system is claiming that it’s not obvious.
I may have misunderstood him about the max 20mm range because I have some trouble understanding Taiwan Guoyu but I’ll never be carrying around bars of gold that big so it’s not a practical issue for me. 10mm is my max.
If anyone is buying bars 20mm thick, they probably have enough money to have it melted and re-cast. Retail buyers aren’t buying gold bars thicker than 10mm.
Realistically anyone doing this will scam about a couple of ounces at most with 10mm thick bars, but that’s a pretty significant amount of money. If they stuck say 3mm tungsten rods in there it could escape xrf.
That’s fine, but it’s not really the point in a conversation about the technical limitations of the technique.
I think if I’m rich enough to buy 10mm thick gold bars, I’d want it X rayed, not just XRF, you know long exposure X ray that can go through lead panels? If someone’s hiding tungsten inside the X ray will tell you. That in addition to XRF should satisfy anyone.
Considering tungsten is really cheap compared to gold. A pack of 10 3mm tungsten electrode for TIG welding is like 500nt if you buy it from Taobao.
How awesome would it be if banks started installing x-rays.
I would consider using the same gold shops that the overseas foreign workers OFWs use.
OFWs only look for the best value and those shops must give the best value.
Like outside Zhongli train station.
Sure. Speculation works well until one is caught…
