[en] In this paper we give the main characteristics of a great dynamic fission chamber (11 decades)

[en] This invention refers to a detector of particles that enables accurate determinations to be effected at high temperature, irrespective of the particle flux to which it is subjected (for example, a neutron flux in the core of a reactor) and preferentially is of elongated shape and particularly reduced radial section. According to the invention, the specifications of this detector include a body in a single piece, made of a ceramic material, in which are embedded and sealed two concentric tubular electrodes forming between them an annular chamber filled with a gas under pressure and electric wires connecting the electrodes to the outside of the body

[en] Multiplate fission chambers were used in experiments at TRIUMF to measure the absolute muon induced fission yield. To determine the yield, the fission chamber detection efficiencies must be known. In this paper, the methods of efficiency calibration have been discussed. (author)

[en] Published in summary form only

[en] A prototype fission chamber has been extensively tested and several chambers assembled in preparation for the Fast Flux Test Facility - Reactor Characterization Program (FFTF - RCP). The major portion of our report concerns the chamber design and performance characteristics. The absolute efficiency of the device will not be explicitly discussed. In ruggedizing the chamber, great care has been taken not to significantly alter the absolute efficiency as compared to the more conventional NBS configuration. This configuration and the measurement of absolute fission rates have already been rigorously discussed in an earlier report. The FFTF characterization effort will be reported in a future paper after the measurements have been completed

[en] The neutron detector consists of a fission chamber and a compensated ionisation chamber for neutron flux between 1 and 10¹⁰/cm²/sec. The maximum flux for neutron detectors in impulse counting operation is limited by the saturation and the minimum which is detectable due to DCα signal noise. The detector contains a small quantity of UO₂ which is deposited on an electrode. Part of the detector is in the form of a compensation chamber. It contains Ra²²⁶. The α signal noise is suppressed by the reduction of the U 234 content in UO₂ to less than 100 ppm. The γ compensation signal can be produced by an external circuit. (DG) 891 HP

[en] The main causes of residual activation currents in dc mean current ionisation chambers are briefly discussed. Theoretical and experimental aspects of fission product and wall activation effects are considered and performance data for a typical chamber derived. The likely ways in which this performance can be changed by modifications to the design are stated. (author)

No abstract available

No abstract available

[en] Fission Chambers are gas-filled type detectors that operate in the ionization chamber regime, which is without electron multiplication. As the fill-gas is not directly ionized by neutrons, fission chambers are lined with fissile material that through interaction with neutrons fission products are produced, are highly ionizing particles. Pulse type operation of these detectors are used for neutron flux measurements during start up and shut-down reactor conditions in which pulses of high amplitude produced by fission products can be easily discriminated from those produced by alpha radiation from uranium and also from the external gamma field. With current or current fluctuation mode operation (Campbell) the use of these detectors can be extended for the whole range of reactor operation. In this work, it is presented the development and construction of a fission chamber at IPEN-CNEN/SP. Furthermore, the material and techniques used and also the operational characteristics obtained with the first prototype are given. (author)