The attached spectrum is for the 90 degree X-ray detector taken for about 3 hours with 118Te52+.
We see two peaks at ~29 keV (K-alpha) and 44 keV (K-REC).

The resolution is about 1.5 keV, and the signal-to-background ratio is also really bad.

The increase of background events at higher E might be induced by Compton scattering of a high E gamma ray from the BaF detectors, which are active and sit close by (not anymore).