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.
![](https://www.madexp.it/wp-content/uploads/2024/07/i131_lead-castle-e1720102241602-1024x443.jpg)
Beta flux measure
![](https://www.madexp.it/wp-content/uploads/2024/07/gamma_i131-576x1024.jpg)
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.
![](https://www.madexp.it/wp-content/uploads/2024/07/beta_i131-e1720102401362-847x1024.jpg)
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).
![](https://www.madexp.it/wp-content/uploads/2024/07/interspec-1024x461.jpg)
Gamma spectrum of I131
I131 this is the spectrum in “.csv” format if you wish to play with it.