A method of operating a radiation-detecting device includes charging a first charge storage region of a charge storage structure to place a first charge value at the first charge storage region, and charging a second charge storage region of the charge storage structure to place a second charge value at the second charge storage region. The method further includes conducting a first read operation to determine a change in the first charge value at the first charge storage region at a first time after charging the first charge storage region, and determining a first radiation flux value for an environment containing the charge storage structure based on the change in the first charge value at the first time.