Updside/Downside to Plastic Inner Layer?

[Mike S]

I've seen some shield designs that use plastic inner layers either intentionally to absorb low energy x-rays, or as mechanical components of the shield design. I've got a few questions about the practice, since I'm using a plastic core for my current shield and wondering which direction to go for future shield designs and improvements. I'm using an interim "test shield" at the moment that has a 3D printed 3mm thick PETG core.

1. Has anyone noticed a practical improvement by adding a plastic liner? It seems like anything blocked would be too low energy to be detected by the detectors we are using.

2. Has anyone noticed a downside due to increased backscattering when plastic was added? I haven't done any experiments to check this specifically, but I think I'm seeing some increased backscatter when I add plastic near the detector (my design has some 3D printed parts to support the detector and hold the sample).

Thanks for any input!

Mike S.

[cicastol]

I've seen some shield designs that use plastic inner layers either intentionally to absorb low energy x-rays, or as mechanical components of the shield design. I've got a few questions about the practice, since I'm using a plastic core for my current shield and wondering which direction to go for future shield designs and improvements. I'm using an interim "test shield" at the moment that has a 3D printed 3mm thick PETG core.

1. Has anyone noticed a practical improvement by adding a plastic liner? It seems like anything blocked would be too low energy to be detected by the detectors we are using.

2. Has anyone noticed a downside due to increased backscattering when plastic was added? I haven't done any experiments to check this specifically, but I think I'm seeing some increased backscatter when I add plastic near the detector (my design has some 3D printed parts to support the detector and hold the sample).

Thanks for any input!

Mike S.

So nice, great idea , a lead sheet sprocket !!

No practical improvement here, with plastic only there is just a little bit more backscattering, but nothing to worry about , with a complete z grade shield (pewter/tin and copper) backscatter is much more intrusive especially if the shield walls are near detector (little gap, like our amateurs shields).
Plastic near walls and detector may be especially useful for strong beta emitter to lower Bremsstrahlung continuum, absorbing beta particles hitting walls.

[Mike S]

So nice, great idea , a lead sheet sprocket !!

No practical improvement here, with plastic only there is just a little bit more backscattering, but nothing to worry about , with a complete z grade shield (pewter/tin and copper) backscatter is much more intrusive especially if the shield walls are near detector (little gap, like our amateurs shields).
Plastic near walls and detector may be especially useful for strong beta emitter to lower Bremsstrahlung continuum, absorbing beta particles hitting walls.

Thanks!

I had forgotten about the betas; I can see that as a benefit to having plastic walls.

--Mike