PHYS291 Project Documentation

This is the documentation for a project in PHYS291. PHYS291 is an UiB-course aimed at giving an introduction to computer science and using IT-resources for master thesis. The course requirement is a project in which C++ should be used in Linux environment with the CERN-developed data analysis framework ROOT.

Project description - Results - git log - Code

By Ola S Grøttvik

Project description

Radon gas in basements and other closed spaces is a serious radiation source and is often the biggest contribution to the yearly radiation dose. It is therefore neccessary to make measurements and find which areas that are most affected and which houses the radiation reach dangerous levels. The activity can be measured by placing coal boxes in the areas where the radiation is predicted to be significant. The boxes contain activated carbon which have small, low-volume pores that increase the surface area availeble for adsorption or chemical reactions. This means that the carbon can adsorb quite a portion of radon. The boxes should be open in about 72 hours, and then be analysed within a day or so. The radon levels can then be measured by detecting the gamma radiation.

To find the amount of radiation we need the amount of counts minus the counts resulting from the background:

Ntot = Nbox - Nbackground

r c1.png c2.png

The radiation in Bq/m3 is calculated from the formulas above. R is the radon concentration, N the amount of counts, while C1 and C2 are correction factors. They are based on how much time that has passed since the box were closed before it was measured, and how long the box have been opened. Lambda is the deintegration constant for Rn-222 and therefore is ln2/91,68.

The initial project goals

  • Create a simple script that creates a spectrum which resembles significant radon concentration + a background spectrum. Save the spectrum to a textfile
  • Create a simple script that reads the created files and analyzes the spectrums to get concentration and dose levels.
  • Write a larger program which creates multiple spectra with varying degrees of radon. The spectra will be assosciated with an address.
  • Write a larger program which on the basis on user inputs handles all the spectra and can present data in a nice and readable text file. Alerts the user of alarmingly high dose levels.
In other words, create a program that will simplify the analysis of a large set of recorded radiation measurements. The finished program makes the following assumptions:
  • The relationship between energy level and channels are known. The calibration constant is hardcoded into the source code.
  • 100 Bq/m3 gives a radiation dose of ca. 2 mSv per year.
  • 4 pCi/l is over acceptable radiation levels - this equals 148 Bq/m3. This is the number set by US Environmental Protection Agency.