Du Penetrator ID?


I received the attached photos with a request to identify this DU penetrator? The weight is 3.65 Kg… Length is about 6.25 inches, and diameter about 1.75 inches. There appears to be no markings on it. Interestingly, though not necessarily germane to its identification, is an image with a meter up-close showing around 11 Micro Sieverts. At about 18 inches the meter drops to one quarter (3.1 mSv) and at 10 feet it is almost nothing.!

Chris P.


I wonder if this really is a DU penetrator.


In Keith Lampear’s 2009 SLICS display, he showed a D.U. penetrator that was reading 1.82 millirads per hr on a digital counter that he had set up next to it. Not sure what that means as compared to lead, steel or whatever, but maybe this is what D.U. typically reads out as? 1.82 millirads is basically equivalent to 18 microsieverts.


We were using the same kind of projectiles in Switzerland for the Centurion 10.5 cm canon. Tungsten penetrator subcaliber. Of british origin???
The one I have are without painting.


This is why I am having my doubts.


What is this a cut-a-way of?


It is of a 105mm APDS-T as the British or the US made them for L7 tank guns.
There is also a second variant of the core but I do not know who used which version.
Also the US had 2 models of these and could have been using both core designs maybe.



The detector in the picture uses a Sodium Iodide crystal for detection, so it doesn’t detect alpha particles and most (lower energy) Betas. Those types compose the majority of radiation emitted by Depleted Uranium. There are also some measurable gamma energies, but the amount emitted is very low.

I would suggest you do a background count for at least 5 minutes well away from the object to establish what the natural occurring radiation levels are before measuring the activity of the object.

Then measure the activity of the object for the same amount of time and finally subtract the background value from that result This will give you a better idea of the “true” activity of the object.

FYI, since DU is 19.1 gm/cm3 a cylinder of such with dimensions of 6.25 in (15.875cm) and a dia of 1.75in (4.445cm) would have a volume of (pii x radius squared x height) or approx 246 cm3.
246 cm3 x 19.1= 4705 gm or 4.7 kg That shape obviously has less mass than a cylinder but it might be in the range for DU.

Just some thoughts.



Thanks Guys and particularly Pat.

I appreciate the info though I am a little confused.

Pat: I understand what you’re saying about the meter the guy used and I will pass that on to him. I will also get more accurate measurements from him and calculate the volume of alloy used to determine if that supports his thought that it is DU penetrator.

My confusion comes from suggestions that it is the tungsten penetrator used in various 105mm projectiles. Does the reading on meter the guy has used support the idea that it is tungsten or would it have to be a tungsten alloy which contains some form of radioactive element (perhaps thorium) ?? And, would thoriated tungsten be used in 105mm penetrators anyway?

Clearly, I haven’t a clue what I’m talking about !!

Chris P.



The additional measurements would be to determine whether the meter is measuring just natural background and/or how much activity the object actually contributes. The object appears to be on a lead sheet. if so, I would remove that before counting just to eliminate the possibility that the sheet is providing some of the activity (due to contamination). These activity levels are very low and difficult to measure accurately even with professionally shielded equipment.

As to thoriated tungsten, I do not believe so as the decay chain of Thorium is primarily alpha emission. The trace isotopes of thorium which decay by beta emission have half-lives measured in days. Again, this instrument is not capable of measuring alpha decay.

One more longshot thought would be to check the paint and see if it glows in the dark. If so, it may contain radium. Again a alpha emitter but it does also have a weak gamma ray which could possibly be measured by the device. Remote possibility.



Super Interesting!

I was not aware of any DU cored APDS 105mm or 120mm projectiles used by the US or UK? Most that I am familiar with all use tungsten?



Thanks again Pat - I appreciate your help and patience!
Chris P.