公开(公告)号：US3717766A

公开(公告)日：1973-02-20

申请号：US3717766D

申请日：1970-10-22

Applicant: COMMISSARIAT ENERGIE ATOMIQUE

Inventor： ALLARD G ,  LANSIART A

IPC: H01J47/14 ,  A61B6/00 ,  G01T5/12 ,  H01J47/10 ,  G01T1/18

CPC classification number: H01J47/10 ,  A61B6/4258

Abstract: A DEVICE FOR DETECTING AND VISUALIZING THE SPATIAL DISTRIBUTION OF RADIATION COMPRISES THREE PARALLEL ELECTRODES DISPOSED WITHIN AN ENCLOSURE WHICH CONTAINS AN IONIZABLE GAS MIXTURE AND CONSISTING OF A GRID BETWEEN A CATHODE WHICH IS TRANSPARENT TO SAID RADIATION AND AN ANODE. THE GRID DEFINES WITH THE CATHODE A DETECTION SPACE IN WHICH THE INCIDENT RADIATION CAUSES IONIZATION OF THE GAS MIXTURE AND DEFINES WITH THE ANODE A SPACE FOR THE MULTIPLICATION OF ELECTRONS WHICH ARE PRODUCED IN THE DETECTION SPACE AND PASS THROUGH THE GRID, THEREBY INITIATING THE PRODUCTION OF SPARKS. THE DETECTING DEVICE FURTHER COMPRISES AN EXTERNAL CIRCUIT WHICH PROVIDES A CONNECTION BETWEEN THE ANODE AND THE GRID AND INCLUDES MEANS WHICH ARE TRIGGERED BY THE SPARKS PRODUCED WITHIN THE MULTIPLICATION SPACE IN ORDER TO SHORT-CIRCUIT SAID MULTIPLICATION SPACE TEMPORARILY AT THE TIME OF APPEARANCE OF EACH SPARK. THE ANODE IS ESSENTIALLY PROVIDED WITH TWO CONDUCTIVE COATINGS WHICH ARE ELECTRICALLY CONNECTED TO EACH OTHER RESPECTIVELY ON THE TWO FACES OF AN OPTICALLY TRANSPARENT SUPPORT PLATE. ONE OF THE TWO COATINGS HAS HIGH SURFACE RESISTANCE AND LIMITS THE ELECTRON MULTIPLICATION SPACE WHILST THE OTHER COATING HAS LOW SURFACE RESISTANCE.

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