What is the smallest scale of effective composting experiment in laboratory?

Well it is very easy to work out the amount of the first radioisotope in a simple decay chain such as P-32 decaying to S-32

For the a unstable daughter such as in Mo-99 to Tc-99m to Tc-99, it is quite easy to work out the Tc-99m activity.

For the second radioactive daughter such as Tc-99 it is quite hard (big equation) to work out the activity at a given time.

What about for a third radioactive daughter such as U-234 in the following chain, where we start with pure U-238.

U-238 to Th-234 to Pa-234 to U-234

To measure:

Radon

Uranium

Radium

Thorium 

I need a reliable procedure to dissolve bitumen nuclear waste samples in order to perform radiological characterization of hard to detect radionuclides (pure beta emitters).

We have been using HPGe detectors for evaluating the level of natural and artificial radionuclides in different kinds of environmental samples. Parallelly, we also provide radioactivity testing services to ensure that there are no consequences triggered due to the consumption of highly radioactive food materials. We usually use certified reference material (CRM) collected from IAEA for calibration, performance evaluation (PE), method validation (MV), and QC. We are planning to collect a CRM of milk powder spiked with Cs-137...but could not find it anywhere? Could anyone of you please help me find it? It is urgent for us as we are working on getting ISO17025 accreditation by this year.

I did some analyis by gamma-spectrometry (following the NF ISO 18589-3)  and I had my results.

In view to calculate an index activity of my material, I need Th232 activity. Is that an average of the values obtained for Ac228 and Pb212? Thank you

Decay schemes

radioactive materials

radionuclides

software