Analysis of Iodine-131 Sample

I recently received a sample of the isotope I-131.
At the time of my initial tests, the sample had an activity of approximately 450 kBq.
The sample consists of four disk-like pellets of pure carbon, infused with the isotope. These disks are enclosed in a plastic vial.

Beta flux measure

Gamma emission measure at point blank

The gamma emission due to the decay of I-131 to Xe-131 is approximately 10 µSv/h when in contact with my energy-compensated x-ray gamma probe.
The polyethylene vial attenuates the beta emission from 450 particles/cm²·s at 1 cm distance from my beta flux meter to 27 particles/cm²·s.

Beta flux measure at 10mm distance

For my tests, I used a calibrated MKS-01E radiometer to measure beta flux and gamma emission.
Subsequently, I traced the gamma emission spectrum using my spectroscopy system composed of NIM modules and a NaI(Tl) detector, 40mm in diameter and 50mm in length with a central well.
The detector is installed in a lead shield 25mm thick in all directions.

I extracted the data using EPICS+mca and AmericiuMCA software and performed the final analysis with Interspec (which, however, recognized an acquisition time of 920 seconds instead of the actual 92 seconds).

Gamma spectrum of I131

I131 this is the spectrum in “.csv” format if you wish to play with it.