THEFOLD SPEED ACCELERATOR FOR RESISTIVE ANODE IMAGING AND OPTICAL ANODE ALTERNTIVE

FOR IMAGING OR POSITION-SENSITIVE DETECTION (PARTICLE COUNTING) OF LOW-INTENSITY ELECTRON, ION, OR PHOTON BEAMS, A COMMON APPROACH IS TO USE A MICROCHANNEL PLATE (MCP) INTENSIFIER FOLLOWED BY A POSITION-SENSITIVE ANODE. THE RESISTIVE ANODE ENCODER (RAE) IS AN ANODE DESIGN THAT IS PROVEN TO BE RUGGED, INEXPENSIVE, AND USEFUL, PARTICULARLY WHEN TIMING OF INDIVIDUAL PARTICLE ARRIVALS IS IMPORTANT. LIMITATIONS OF THE DEVICE INCLUDE LIMITED MAXIMUM COUNTING RATE DUE TO RC DELAYS AND ELECTRONIC PROCESING TIMES, AND THE NEED TO USE HIGH VOLTAGE VACUUM FEEDTHROUGHS AND BREAKDOWN-PRONE STANDOFF CAPACITORS ON THE SIGNAL LEADS FOR IN-SITU VACUUM APPLICATIONS WHERE THE ANODE MUST BE BIASED TO HIGH VOLTAGES. RESEARCHERS ARE DEVELOPING A FAST NEW GENERATION OF RAE-TYPE DETECTOS. PULSE PROCESSING ELECTRONICS, APPLICABLE TO EXISTING RAE DEVICES, INCREASE THE SIGNAL RATE OVER THAT OF CURRENT DETECTORS BY A FACTOR OF TEN. THE NEW DTECTOR REPLACES THE RESITIVE ANODE WITH ITS OPTICAL ANALOG, USING A SCINTILLATING LIGHTGUIDE TO CONVERT AN ELECTRON BURST INTO OPTICAL PULSES, WHICH CAN BE TRANSMITTED OVER OPTICAL FIBER SIGNAL LEADS. THE ADVANTAGES INCLUDE INHERENT HIGH-SPEED, NOISE IMMUNITY, AND NON-CONDUCTING SIGNAL LEADS THAT ALLOW THE DETECTOR TO FLOAT AT HIGH VOLTAGE.