Abstract:
A gas-filled proportional counter camera that images photon emitting sources has been provided. A two-dimensional, positionsensitive proportional multiwire counter is provided as the detector. The counter consists of a high voltage anode screen sandwiched between orthogonally disposed planar arrays of multiple parallel strung, resistively coupled cathode wires. Two terminals from each of the cathode arrays are connected to separate timing circuitry to obtain separate X and Y coordinate signal values from pulse shape measurements to define the position of an event within the counter arrays which may be recorded by various means for data display. The counter is further provided with a linear drift field which effectively enlarges the active gas volume of the counter and constrains the recoil electrons produced from ionizing radiation entering the counter to drift perpendicularly toward the planar detection arrays. A collimator is interposed between a subject to be imaged and the counter to transmit only the radiation from the subject which has a perpendicular trajectory with respect to the planar cathode arrays of the detector.
Abstract:
AN IMPROVED DIGITAL RADIATION DOSIMETER OF THE OSCILLATING IONIZATION CHAMBER TYPE INCLUDING A GAS DIODE CONNECTED IN SERIES WITH THE CHAMBER ANODE HAS BEEN PROVIDED WITH IMPROVED OPERATION AND MINIATURIZATION OF THE DETECTOR CHAMBER. THIS IS MADE POSSIBLE BY A CIRCUIT THAT ADDS STROBE PULSES TO THE NORMAL DC CHAMBER BIAS VOLTAGE SO AS TO ALLOW THE GAS DIODE TO DISCHARGE EVEN THOUGH THE ACTIVE CHAMBER VOLUME IS NOT LARGE ENOUGH TO PRODUCE SUFFICIENT DIODE BIAS CURRENT AT LOW RADIATION EXPOSURE RATES.
Abstract:
An alarm dosimeter has been provided which features an improved integrating pulse ionization chamber of the type containing an hermetically sealed gas diode. Improved operation and miniaturization of the chamber are made possible by a ringing choke converter high voltage supply having a ripple-type output that insures discharge of the gas diode.