Informatics

radiation detection with Arduino: cumulative counter (2)

After modifying the arduino program for measure radiation with cooking-hacks.com’s radiation board in a previous post, I realized that it wasn’t still perfect for background radiation measures:

Background radiation measures are typically of very low values and given the stochastic nature of radiation (see graph on previous post), it takes some minutes to achieve a correct cumulative medium value, so a clock counter is needed.

I slightly modified the program to add an incremental clock on the lower right of the LCD: the clock shows up for the first 2 minutes and a half, which is the minimum time for a measure. From there on to five minutes, the clock alternates every ten seconds with the corresponding accumulated uSv/h value for the CPM (counts per minute). From 5 minutes on the clock is not showed anymore, just the accumulated uSv/h value, and a vertical bar appears on the middle of the second LCD line to indicate that the five minutes mark has been passed.

Here is the complete code: radiation_shield_buffer.ino

Also as git repository here.

Also, the different units for radiation measure are very confusing and some of then, now deprecated, are found on textbooks and articles… So I stuck a little table to my carton box, with fast conversion factors.

CPM to μSv/h:     0.00812    (with this detector)

Human exposure to natural background radiation,
global average:
2.4   mSv/a    = 0.27     μSv/h avg

0.081 μSv/h = 0.72     mSv/a ~ 10 CMP
0.154 μSv/h = 1.36     mSv/a ~ 19 CMP
0.162 μSv/h = 1.44     mSv/a ~ 20 CMP
0.244 μSv/h = 2.17    mSv/a ~ 30 CMP
0.27  μSv/h = 2.4     mSv/a ~ 33.2 CMP <—-
0.325 μSv/h = 2.88    mSv/a ~ 40 CMP
0.406 μSv/h = 3.61    mSv/a ~ 50 CMP
114.1 μSv/h = 1      Sv/a
1000  μSv/h = 8.766     Sv/a

1 Gy = 1 Sv
(for X, beta and gamma rays)

1 Sv = 100 rem
1 Gy = 100 rad

One roentgen ~ 1 rad = 0.01 Gy ~= 0.01 Sv
(in soft tissue)

Oh, and added a power switch, so now the detector is almost perfetc.

arduino radiation portable detector in a small box

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