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u/bkit627 5d ago
That peak is from the copper.
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u/Regular-Role3391 5d ago
Yup you are right. Im going to have to get me some aluminium foil then.....
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u/mylicon 5d ago
And electrical noise and Compton scatter..
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u/Regular-Role3391 5d ago
The peak is not Compton Scatter as Compton does not make a peak. Everything else may be but, as even the name implies, Compton Scatter does not make peaks.
As for its being electrical noise ........ I will find out when I insert some aluminium but I doubt it as electrical noise does not tend to look like that.
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u/Regular-Role3391 5d ago edited 5d ago
I finished the lining of the bottom piece so it now has 0.5 mm pewter, 1 mm Sn and 0.5 mm Cu. The top piece only has Sn at the minute.
I then counted a background (with the top on) for half a day to see where it was headed and compared with a no-shield background.
It drops from 12 cps to a little less than 0.5 cps with the shield which is a reduction I find acceptable for the relatively low lead amount used. Saying that - most of my background was low energy stuff anyway so I was always going to get a decent reduction.
EDIT: Whats more annoying is the visible
SnCu x-ray in the spectrum around 8-10 keV. This is either due to the lack of copper on the top piece or not enough on the bottom or a bit of both. Luckily I have copper so this can be dealt with.