Today's radiation graph. All normal. |
Last 7 day's radiation graph. The high peak was caused by an hardware error (faulty connector) |
Personal Geiger counter, radiation measurements in the city of Goes, The Netherlands. Note: I'm not using officially calibrated equipment, so don't draw any conclusions. Just use the graphs for comparing variations over time.
Browsing the internet, I found some relatively cheap ex-army radiation detectors at an army-dump shop. One of them appeared to be suitable to even detect the (usually low) background radiation levels: A Frieseke & Hoepfner FH40T Geiger counter (fitted with a FHZ76V energy-compensated geiger-mueller tube), sensitive to γ (gamma) radiation and β (beta) radiation over 0.25MeV.The FHZ76V tube actually contains a Valvo 18550 tube, which is equivalent to Centronics ZP1320, Mullard Mx164 and LND-713 (found in this Probe Selection Guide and here)
The specs of the ZP1320 tube claim a sensitivity of 9cps/mR/h for Cs-137 (540cpm/mR/h). For 'normal' background (0.025-0.045mR/h) this results in a counting rate of approx.10-20cpm.. Where I live, I measure values varying between 4cpm up to 25cpm. This variation is caused by the randomness of the decay of radioactive elements.
Note:
Today's radiation graph. All normal. |
Last 7 day's radiation graph. The high peak was caused by an hardware error (faulty connector) |
Leuk dat hier meer mensen mee bezig zijn, ik zag deze pagina door referrals in de statistieken van mijn site :)
ReplyDeleteEen kleine tip, nanosievert wordt niet zoveel gebruikt, eerder een stapje omhoog, microsievert.
bedankt voor je reaktie, Johan. Leuk dat je het zag vanuit de statistieken van je eigen site.
ReplyDeleteIk heb je tip gebruikt. de y-as van de grafieken is nu in µSv/h. In de legend gegenereerd door rrdgraph blijft het helaas nano, daar heb ik geen invloed op.