Dosimeter charging and/or reading apparatus

Apparatus for charging a dosimeter having a capacitor connected between first and second relatively stationary electrodes, an ionization chamber exposed to at least portions of said first and second electrodes to discharge said capacitor when ionizing radiation penetrates said chamber, a movable electrode electrically connected to said first electrode which deflects varying amounts depending upon the charge present on said capacitor, a movable electrical contact shiftable between a noncharging position spaced from said first electrode and a charging position contacting said first electrode, and a first electrical insulator mounting said movable contact and said second electrode in spaced relation when said movable contact is in its charging and noncharging positions, said dosimeter charger apparatus comprising:

• a first charging electrode and a second charging electrode,
• a second electrical insulator mounting said first and second charger electrodes in fixed spaced relation to each other susceptive of contact with said movable contact and second dosimeter electrode, respectively, when it is desired to charge said dosimeter,
• a high voltage D.C. supply connected between said first and second charger electrodes for applying therebetween a charging potential when said power supply is energized,
• a first switch means connected to energize and deenergize said power supply when actuated and deactuated, respectively,
• means mounting said second insulator for movement between an inactive position in which said first switch means is deactuated to de-energize said power supply and an active position in which said first switch means is actuated to energize said power supply, and
• a solid state electronic switch connected between said first and second charger electrodes for short-circuiting said first and second charger electrodes when placed in a conductive condition by movement of said second insulator to its inactive position, said solid state electronic switch being nonconductive when said first switch means is actuated and said power supply is energized by movement of said second insulator to its active position,
• said charger apparatus being operative to charge said capacitor by first engaging said movable contact and second electrode of said dosimeter with said first and second electrodes of said charger, respectively, and thereafter when so engaged moving said first dosimeter electrode toward said first switch means to thereby sequentially (a) advance said second insulator toward said first switch means to its active position to actuate said first switch means and energize said power supply to apply a potential between said first and second charger electrodes and render nonconductive said solid state electronic switch, and (b) move said movable contact into contact with said first dosimeter electrode to charge said capacitor from said energized power supply via a first series path including said first charger electrode and said movable contact and first electrode of said dosimeter and a second series path including said second electrodes of said dosimeter and charger,
• said charger apparatus being operative upon movement of said first dosimeter electrode away from said first switch means to sequentially (a) disengage said first dosimeter electrode and movable contact while said movable contact and first charger electrode remain engaged and said second charger and dosimeter electrodes remain engaged, (b) deactuate said first switch means to de-energize said power supply and place said solid state electronic switch in its conductive state while said movable contact and first charger electrode are engaged and said second charger and dosimeter electrodes are engaged to short-circuit said movable contact and second dosimeter electrode via said first and second charger electrodes, and (c) disengage said movable contact and second dosimeter electrode from said first and second charger electrodes, respectively.