I propose modifying the app. so the thorium is isolated from the chamber and both a thick and thin window G-M tubes inserted in a reduced size chamber. The thick window will detect the long (~eleven hr) and the following increase of the short (~one hour). Any way, that one is nicely complicated. OTOH the counter detecting the alphas also complicated, (too lazy to think about it.) Ideally one might? make a magnetic separator, possible?, as the alphas are monoenergetic.
bc …. tried separating the betas from the gammas from his Cs source, ended up ruining his only good tube, not knowing only the front of the tube is Al the rest ferromagnetic. (higher Z to make the tube sensitive to gammas). He's conversing with LND about manufacturing an all Al tube.