Dosimeter for photometric applications
First Claim
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1. A temperature independent dosimeter for measuring an amount of irradiation, which comprises:
- a photodiode, operating in its photovoltaic mode, which produces a signal that is amplitude-proportional to the amplitude of the sensed irradiation and is substantially free of temperature effects;
means coupled to the output of the photodiode for converting the signal to a plurality of pulses that are proportional in frequency to the amplitude of the signal;
said converting means comprising a pair of operational amplifiers, with the inverting input of one of said operational amplifiers being responsive to the output of the photodiode;
means coupling the output of said one operational amplifier to the inverting input of the other operational amplifier;
feedback means from the output of said other operational amplifier to the inverting input of said one operational amplifier;
means for counting said pulses; and
means for terminating the irradiation when the count reaches a predetermined amount.
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Abstract
A temperature independent dosimeter is provided for measuring an amount of irradiation of a predetermined frequency. A photodiode (24) operating in its photovoltaic mode is irradiated with the irradiation to produce a signal that is amplitude-proportional to the amplitude of the irradiation. The signal is converted by a pair of operational amplifiers (89, 96) to a plurality of pulses that are proportional in frequency to the amplitude of the signal. The plurality of pulses is counted by a counter (20) and the irradiation is terminated when the count reaches a predetermined amount.
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Citations
4 Claims
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1. A temperature independent dosimeter for measuring an amount of irradiation, which comprises:
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a photodiode, operating in its photovoltaic mode, which produces a signal that is amplitude-proportional to the amplitude of the sensed irradiation and is substantially free of temperature effects; means coupled to the output of the photodiode for converting the signal to a plurality of pulses that are proportional in frequency to the amplitude of the signal; said converting means comprising a pair of operational amplifiers, with the inverting input of one of said operational amplifiers being responsive to the output of the photodiode; means coupling the output of said one operational amplifier to the inverting input of the other operational amplifier; feedback means from the output of said other operational amplifier to the inverting input of said one operational amplifier; means for counting said pulses; and means for terminating the irradiation when the count reaches a predetermined amount. - View Dependent Claims (2, 3, 4)
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Specification