For personnel working in radiation areas, Direct Reading Dosimeters provide an accurate and instantaneous indication of accumulated exposure. Accurate to 10% of True Dose for Cs-137 or Co-60 gamma. Less than 0.5% leakage of full scale in 24 hours at 50° C. Hermetically sealed. Resembling fountain pens in size and appearance, they contain a quartz fiber electrometer and compound microscope. The fiber is set at zero with a battery operated charger. As X- or gamma rays strike the charged Dosimeter, the fiber moves up scale in proportion to the radiation exposure.