The BaF2 detectors planned to be installed at the target induce an additional background in the x-ray detectors sitting below inside the target chamber.
We made test measurements with an x-ray detector for estimating the background in the region of interest for our K-REC measurements (35 to 50 keV).
For the interval [35-50 keV]:
Normal background level: 0.065 (s*keV)^-1
BaF2 in 5cm distance: 0.078 (s*keV)^-1
This is an increase by about 22%
Assuming an increase by 100% induced by 6 BaF2 in the vincinity of the Ge-detectors this seems acceptable.
However additional BaF-induced peaks are also visible at ~30 keV and ~60 keV. While these are not in the region of interest for the K-REC, we need to be aware of them!
spectra are available on the Frankfurt exp-astro Server at /home/glorius/e127/ |