Modifying ROI in Visualizer

How does one change the channels used in a Region of Interest (ROI)?

I’m looking for natural radioisotopes and the detector (H100) produced a very nice Bi-214 peak at 609 KeV. Although the “Natural” custom library I created has Bi-214 in it, Visualizer Marks the peak as an Unknown at 608 KeV.

I’d like to adjust the ROI so it is centered better, hoping that Visualizer would then ID the peak correctly. That, or I’d like to manually ID the 609 KeV peak as Bi-214. Btw, I have tried using the “Isotopes near…” method several times, but it doesn’t seem to “take”.

Please advise.

I’m a engineer at H3D. Can you send the .n42 file to me at dgoodman (at)

Our most recent isotope ID logic, which I don’t know if you instrument has, reports unknowns if the isotope isn’t detected. Is Bi-214 detected in your case? It may require multiple lines, other than the 609, to be sure and report the detection. However, in general 1 keV of shift on photopeak centroids should be handled by our algorithms.

David… .n42 file sent to your email.