Starting with theremino -Newbie Question

[sgt_bear]

Hello

I just finished my homemade detector-driver (basically the theremino version, but with an onboard sound-card chip to avoid modifying a sound-stick)

I plugged it in and it seems to work pretty good. But i have a question. See my spectrum attached

Clealy the Am-241 i used is the big peak there, so at least the detector and driver put out some kind of a valid, usable signal. So i trimmed to the Am-241 peak, and then placed a Lu-176 piece in front of the detector. As you can see, the Peaks for Lu176 are there, but off the line, if i trim to the lu the americum becomes off.

How can this be fixed?
Is it a configuration problem?
Can it be a hardware-problem?

[lodovico]

Hello,
you have to trim with the equalizer, did you try it ?
Lodovico

[Sebastien_billard]

Just use the energy linearizer to move the peaks as you wish.

[pilgrim]

As Luuk explained here https://www.gammaspectacular.com/phpBB3 ... f=14&t=475, NaI(Tl) loses linearity under 100KeV, so if you calibrate under this energy peaks at at higher energies will be "out from their places".