| 摘要 |
A radiation sensor comprising a chamber (110) for containing a gas, the chamber having a first opening (108a) and a second opening (108b) such that a radiation beam can enter the chamber through the first opening, propagate through the chamber and exit the chamber through the second opening, a gas supply mechanism (112, 114, 116, 118) configured to supply hydrogen or helium into the chamber, a first electrode (121) situated in the chamber, a second electrode (122) situated in the chamber, a voltage source (141) configured to maintain a potential difference between the first electrode and the second electrode, an electrical sensor (143a, 145a, 143b, 145b) configured to measure an electrical current flowing through at least one of the first electrode and the second electrode, the electrical current resulting from ionization of the hydrogen or helium in the chamber caused by a radiation beam propagating through the chamber and a processor operable to determine, from the measured electrical current, at least one of a power and a position of a radiation beam propagating through the chamber. |
