Hi guys,
I did a test with a NaI(Tl) and a LaBr3 crystals to show what happened when they get wet.
Interested ? please read the pdf.
Luuk
High resolution crystals are extreme sensitivity for humidity!
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luuk
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High resolution crystals are extreme sensitivity for humidity!
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GigaBecquerel
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Re: High resolution crystals are extreme sensitivity for humidity!
Although it was already dying it still felt terrible watching it fall into pieces...
Thank you for the interesting report!
Thank you for the interesting report!
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iRad
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Re: High resolution crystals are extreme sensitivity for humidity!
WOW... Thanks Luuk for the heads-up on this potentially big problem with hi-res crystals.
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GigaBecquerel
- Posts: 172
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Re: High resolution crystals are extreme sensitivity for humidity!
Oh, I just realized something!
There's currently a 1.5" LaBr3 on ebay for a pretty good price (cheapest price for the crystal itself is about 1k more than what the whole assembly costs), and thanks to your pdf I think I know now, why it is so cheap.
This is the spectrum shown in the offer...
There's currently a 1.5" LaBr3 on ebay for a pretty good price (cheapest price for the crystal itself is about 1k more than what the whole assembly costs), and thanks to your pdf I think I know now, why it is so cheap.
This is the spectrum shown in the offer...
You do not have the required permissions to view the files attached to this post.
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luuk
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Re: High resolution crystals are extreme sensitivity for humidity!
Hi Lukas,
Yes that is right I saw that too it is for sale for some time now but did not want to put in in my post.
I know who is selling it so it is not so nice to give a negative review also not my job to do that!
His fit (3.7%)is so incorrect that I think the real resolution is more around >4.5%.
Luuk
Yes that is right I saw that too it is for sale for some time now but did not want to put in in my post.
I know who is selling it so it is not so nice to give a negative review also not my job to do that!
His fit (3.7%)is so incorrect that I think the real resolution is more around >4.5%.
Luuk
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GigaBecquerel
- Posts: 172
- Joined: 04 Jul 2020, 07:34
Re: High resolution crystals are extreme sensitivity for humidity!
Hi Luuk,
I figured as much, which is why I didn't post the link. I think there's a good chance he's even in this forum. What makes you think the fit is incorrect?
It looks like it could use some more data, but the fit itself looks correct in my opinion.
Lukas
I figured as much, which is why I didn't post the link. I think there's a good chance he's even in this forum. What makes you think the fit is incorrect?
It looks like it could use some more data, but the fit itself looks correct in my opinion.
Lukas
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luuk
- Posts: 313
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Re: High resolution crystals are extreme sensitivity for humidity!
Hi Lukas,
In my opinion you cannot simply cut of the part that you don't like from a non symmetrical or wide peak, it is a nice way to make a good looking resolution but If I do it like at my work that I think I will get fired right away.
You can (have to)subtract the background but in this spectrum there is almost no background to see left of the peak, but the left fit line should be more to the left and that will give a worse resolution, also the amount of count is way to low for a honest resolution calculation.
And you have to use a reliable algorithm to calculate the resolution but there are many mca's software programs that are giving a to optimistic resolution.
I use to work with professional equipment and the result we get are more realistic than most cheaper software, so some customers are very happy that they get a much better resolution then we give on the test-sheet but it is nice to have happy customers :-)
Luuk
In my opinion you cannot simply cut of the part that you don't like from a non symmetrical or wide peak, it is a nice way to make a good looking resolution but If I do it like at my work that I think I will get fired right away.
You can (have to)subtract the background but in this spectrum there is almost no background to see left of the peak, but the left fit line should be more to the left and that will give a worse resolution, also the amount of count is way to low for a honest resolution calculation.
And you have to use a reliable algorithm to calculate the resolution but there are many mca's software programs that are giving a to optimistic resolution.
I use to work with professional equipment and the result we get are more realistic than most cheaper software, so some customers are very happy that they get a much better resolution then we give on the test-sheet but it is nice to have happy customers :-)
Luuk
