Page 1 of 2
Nickel-coated lead
Posted: 27 Jun 2016, 06:44
by MartinM
Hi,
I'm building my shielding - a 65mm copper tube covered with tin sheets. The inner part:

- IMG_6925.JPG (826.53 KiB) Viewed 28123 times

- IMG_6927.JPG (1.11 MiB) Viewed 28123 times
Outer part is a 125mm PVC tube.
I found a supply of 2.5mm lead granules that are Nickel coated. What do you think about using this for shielding? Would the Nickel coating provide even better Beta-shielding, or could it have additional adverse effects like generating more XRF ?
Re: Nickel-coated lead
Posted: 27 Jun 2016, 18:08
by Sesselmann
Nickel should be okay, most of the x-Ray's are under 10 Kev.
http://nucleardata.nuclear.lu.se/toi/xr ... list&el=Ni
Steven
Re: Nickel-coated lead
Posted: 31 Jul 2016, 20:14
by MartinM
I have finally finished my shielding.
Height: 47 cm, outer diameter 12.5 cm, total weight ~24 kg. Filled with ~3 cm of Pb.
The plug is a 60mm tube also filled with lead granules and Sn + Cu plates.
Thinking about some kind of upper plug, perhaps just some thick (~3 cm) Cu cube placed on the top to avoid extensive machining.

- IMG_7210.JPG (1.03 MiB) Viewed 28047 times

- IMG_7211.JPG (420.16 KiB) Viewed 28047 times

- IMG_7212.JPG (1.41 MiB) Viewed 28047 times
Will follow up with some measurements shortly.
Re: Nickel-coated lead
Posted: 31 Jul 2016, 20:29
by MartinM
Background count reduced from 100-120 cps to 10-15 cps.

- shield.png (5.71 KiB) Viewed 28047 times
Re: Nickel-coated lead
Posted: 31 Jul 2016, 21:17
by MartinM
Here a rather short test of Cs137 calibration source.

- Cs137.png (7.46 KiB) Viewed 28047 times
No significant Pb XRF seen. Note the unexpectedly low resolution of 6.3%
Re: Nickel-coated lead
Posted: 01 Aug 2016, 07:32
by Sesselmann
Excellent build, well thought out and nice result. The Pb x-ray is not even visible in the spectrum.
Note: Great resolution, but you need to select a bit wider region of interest to see the true resolution. Just a few more bins each side where it flares out,
Re: Nickel-coated lead
Posted: 23 Sep 2016, 02:57
by Stanford
How about copper coated lead shot for the same reason?
Re: Nickel-coated lead
Posted: 23 Sep 2016, 03:56
by MartinM
Stanford wrote:How about copper coated lead shot for the same reason?
Similar as Cu - below 10 keV.
Re: Nickel-coated lead
Posted: 23 Sep 2016, 14:16
by Stanford
Super thank you...
I just read that "commercially available lead often contains a significant fraction of antimony, as that helps its material properties (the antimony makes it harder, easier to cast in molds, etc.). But antimony is one of the last materials you'd want in a radiation shield, as it is highly vulnerable to induced radioactivity; that is, being bombarded by gamma rays transmutes the antimony into other radioactive isotopes. Some amount of induced radioactivity is inevitable, but you certainly don't want to have more than the absolute minimum, so lead for shielding has to be very pure.
Is this right? And is antimony free lead shot available?
MartinM wrote:
Similar as Cu - below 10 keV.
Re: Nickel-coated lead
Posted: 23 Sep 2016, 16:11
by MartinM
I don't think that such induced radioactivity can occur in common conditions. It would require high-energy gamma rays which are usually only artificially produced (accelerators, etc.), or other particles like alpha or neutrons that are unlikely to reach the material or occur in sufficient quantity.
But perhaps someone else can better comment on this.