GEM-based fission chamber

Abstract

The invention discloses a GEM-based fission chamber, comprising a GEM detector, wherein the GEM detector is provided with a metal shell, a drift electrode, a GEM film and a collecting electrode; the drift electrode, the GEM film and the collecting electrode are arranged in the metal shell; the GEM film is arranged between the drift electrode and the collecting electrode; the drift electrode, a GEMfilm upper-surface layer electrode and a GEM film lower-surface layer electrode are externally applied with negative voltages which are gradually reduced in absolute values; the collecting electrodeis grounded and is electrically connected with a pulse signal acquisition circuit; a drift region is formed between the GEM film and the drift electrode, and a collection region is formed between theGEM film and the collection electrode; a gas chamber is defined by the metal shell, the drift electrode and the collecting electrode, and flowing ionized gas is arranged in the gas chamber; and a uranium-235 layer is arranged on the drift electrode. The GEM-based fission chamber is high in sensitivity and high in counting rate range, and the requirement for wide-range monitoring of the neutron flux density of the reactor is met in a single-pulse mode.

Description

technical field [0001] The invention belongs to the field of fission chambers, in particular to a GEM-based fission chamber. Background technique [0002] From startup to full power operation of the reactor, the range of neutron flux density can reach 11 orders of magnitude (10 0 ~10 11 n.cm -2 .s -1 ), the monitoring methods are mainly multi-detector combined relay measurement and fission chamber multi-mode combined relay measurement. The advantages of the multi-mode combined relay measurement in the fission chamber are fewer detectors and strong n / γ discrimination, but there are also some shortcomings, such as: thermal neutron detection sensitivity is not high (10 -1 ~10 0 cps / nv), count rate dynamic range is small (neutron fluence rate pulse mode measurement upper limit 10 5 ~10 6 n.cm -2 .s -1 ), monitoring mode switching is cumbersome, etc. SUMMARY OF THE INVENTION [0003] The object of the present invention is to provide a GEM-based monitoring method for t...

AI Technical Summary

Problems solved by technology

[0003] The object of the present invention is to provide a GEM-based monitoring method for the current monitoring of the reactor from start-up to full power using the fission chamber multi-mode combined relay measurement method, which has low sensitivity, small dynamic range of counting rate, and cumbersome switching of monitoring modes. The fission chamber has high sensitivity and high count rate range, in order to meet the wide range monitoring requirements of reactor neutron flux density in single pulse mode

Images