Mu-Metal.

[James Luck]

Hello everyone.

This us a question probably better suited for Steven or Luuk.
What's the most common thickness of Mu Metal used with scintillation detectors? Does the thickness change the overall characteristics of the alloy.
I know why it's used, but I'm yet to hear anyone ( or read ) if its thickness matters, such as any form of radiation I'd imagine the thicker the better.

-james

[Sesselmann]

James,

Good question..

Frankly I have never read any studies on the effect of magnetic shielding. I have pulled apart many detectors and some have thicker 0.6-1.0 mm shielding and others have a thinner 0.1 mm.
I use Ultraperm 80 by 3M in my detectors, it's around 0.004" and wrap it around the PMT.

I suppose the shielding requirement will depend on the environment, remember some detectors might be used in laboratories with cyclotrons and huge magnetic fields, others might sit inside a 4" lead shield.

Steven

[James Luck]

James,

Good question..

Frankly I have never read any studies on the effect of magnetic shielding. I have pulled apart many detectors and some have thicker 0.6-1.0 mm shielding and others have a thinner 0.1 mm.
I use Ultraperm 80 by 3M in my detectors, it's around 0.004" and wrap it around the PMT.

I suppose the shielding requirement will depend on the environment, remember some detectors might be used in laboratories with cyclotrons and huge magnetic fields, others might sit inside a 4" lead shield.

Steven

Thank you Steven.
I figured what you said would be the case, I'll just wait for Luuk to answer when ever before I further my design for a scint.
Of course most of my work never enters much higher than industrial electronic pumps.

[luuk]

Hi James,
Like Steven wrote most solid mu-shields are around 0.8mm, and the real thick ones are 1mm, I don’t think I have seen much thicker than around 1mm.
For standard use I would suggest 0.5-0.8mm that should be sufficient for a detector that is not used at a fixed place but you can “walk” around with it.
If you have a detector in a fixed position just some thin mu-foil direct wrapped around the pmt will do the trick.
Remember that around the cathode so the first few cm from cathode to the back of the pmt the most sensitive part is so there you must be a good shielding, at the end of the pmt the shielding is less important unless you work with a high magnetic field around the detector.
Luuk

[James Luck]

Hi James,
Like Steven wrote most solid mu-shields are around 0.8mm, and the real thick ones are 1mm, I don’t think I have seen much thicker than around 1mm.
For standard use I would suggest 0.5-0.8mm that should be sufficient for a detector that is not used at a fixed place but you can “walk” around with it.
If you have a detector in a fixed position just some thin mu-foil direct wrapped around the pmt will do the trick.
Remember that around the cathode so the first few cm from cathode to the back of the pmt the most sensitive part is so there you must be a good shielding, at the end of the pmt the shielding is less important unless you work with a high magnetic field around the detector.
Luuk

Thank you for the reply, Luuk.

Both you and steven was a great help on the question at hand.

[luuk]

James,
if you need mu-metal I always have some used shield for a hobby price, if you are interested send me a pm with your needs.
Than I can look if I have something for you.
Luuk

[James Luck]

James,
if you need mu-metal I always have some used shield for a hobby price, if you are interested send me a pm with your needs.
Than I can look if I have something for you.
Luuk

Thank you Luuk, once I get time to sit down I'll see the size I'll need for the probe I'm thinking of building.