The Th232 Gamma Spectrum, has seveal peaks stretching out to 2.6 MeV, and it can be tricky to identify the correct peaks. Detectors smaller than 2" x 2" may have difficulty seeing the higher end gammas, which means you are only seeingt part of the spectrum.
The following spectrum was recorded with a Ludlum 44-10 2" detector with GS-1100A2 and PRA, the data was exported to a spreadsheet and graphed. The height of the fine red lines indicate the intensity of the main Gamma peaks. This spectrum was recorded without shielding, and therefore shows a prominent K40 peak at 1460 Kev.
Special thanks to Marek Dolleiser, for helping me with this spectrum, and providing the gamma peak data.
The following table contains the main gamma peaks present in the Thorium spectrum. Gamma peaks with intensity less than 1% have been omitted.
The following spectrum was submitted by Tom at anti-proton.com