a radiation survey meter observed gamma radiation of 150 mR/hr. The air field ionization chamber has a volume of 580 cubic cm. If the electron generated by the radiation in the chamber are swept out by an electric field, what is the current produced?
please answer, thank you so much!
physics - Elena, Saturday, December 8, 2012 at 3:35am
The roentgen is the quantity of radiation which liberates by ionisation 1 esu of electricity per 1 cm³ of air under normal conditions of temperature and pressure
1 electrostatic unit of charge (esu) = 3.33•10⁻¹º C
150 mR/hr =150•10⁻³/3600 R/s
It gives q=(150•10⁻³/3600)•3.33•10⁻¹º = 1.4•10⁻¹⁴ C in 1cm³
and total charge in chamber
Q= 1.4•10⁻¹⁴ •580 =8.1•10⁻¹² C.
I=Q/t= 8.1•10⁻¹² A = 8.1 pA