DOUBLE-SECTION GAS-FILLED IONIZATION CHAMBER Russian patent published in 1998 - IPC

FIELD: neutron detectors, in particular, measuring neutron flows in current channels of reactor control systems, critical assemblies and other neutron sources. SUBSTANCE: device has housing 1 which contains two electrode systems 2 and 3 which provide two sensitive chambers V1 4 and V2 5 which heights are L1 and L2, respectively. First chamber is filled with gas mix or gas under pressure P1. Said gas mix or gas emits ions in reaction with neutrons. Second chamber V2 is filled with gas mix or gas under pressure of P2. Said gas mix or gas does not emit ions in reaction with neutrons. Absolute value of nominal electric power supply of second sensitive chamber provides complete current compensation for γ radiation and is not greater than , absolute value of nominal power supply voltage of first sensitive chamber. Another claim of invention describes device design in which pressure P2 belongs to another given interval. In this case absolute value of nominal power supply voltage of second sensitive chamber, which provides complete current compensation for γ radiation, is not greater than , absolute value of nominal power supply voltage of first sensitive chamber up to absolute value of electric strength of insulation or maximal permissible power supply voltage . All electrodes are insulated from housing by means of support insulators 6. One electrode 7 in first and second sections is insulated from other electrodes; it is high-voltage electrode used for connection through electric terminals 8 and electric line 9 to external nominal voltage power supply 10. Two other signal electrodes are electrically closed and are designed for connection to electric current meter 11. Design of chamber provides possibility to make samples which are compensated for γ radiation current; their thermal neutron detection sensitivity is greater than that of chambers with solid boron-containing radiator by factor of 4-8. They may be used in current channels for measuring thermal neutron flow in range of 2•10²-1•10⁹s^-1•cm^-2 in conditions of background γ radiation. EFFECT: increased sensitivity. 2 cl, 3 tbl, 6 dwg